Unveil the origin of voltage oscillation for sodium-ion batteries operating at -40 °C

Voltage oscillation at subzero in sodium-ion batteries (SIBs) has been a common but overlooked scenario, almost yet to be understood. For example, the phenomenon seriously deteriorates the performance of Na3V2(PO4)3 (NVP) cathode in PC (propylene carbonate)/EC (ethylene carbonate)-based electrolyte at -20 °C. Here, the correlation between voltage oscillation, structural evolution, and electrolytes has been revealed based on theoretical calculations, in-/ex-situ techniques, and cross-experiments. It is found that the local phase transition of the Na3V2(PO4)3 (NVP) cathode in PC/EC-based electrolyte at -20 °C should be responsible for the oscillatory phenomenon. Furthermore, the low exchange current density originating from the high desolvation energy barrier in NVP-PC/EC system also aggravates the local phase transformation, resulting in severe voltage oscillation. By introducing the diglyme solvent with lower Na-solvent binding energy, the voltage oscillation of the NVP can be eliminated effectively at subzero. As a result, the high capacity retentions of 98.3% at -20 °C and 75.3% at -40 °C are achieved. The finding provides insight into the abnormal SIBs degradation and brings the voltage oscillation behavior of rechargeable batteries into the limelight.

Whole-transcriptome profiling and identification of cold tolerance-related ceRNA networks in japonica rice varieties

Introduction

Low-temperature stress negatively impacts rice yield, posing a significant risk to food security. While previous studies have explored the physiological and linear gene expression alterations in rice under low-temperature conditions, the changes in competing endogenous RNA (ceRNA) networks remain largely unexamined.

Methods

We conducted RNA sequencing on two japonica rice varieties with differing cold-tolerance capabilities to establish ceRNA networks. This enabled us to investigate the transcriptional regulatory network and molecular mechanisms that rice employs in response to low-temperature stress.

Results

We identified 364 differentially expressed circular RNAs (circRNAs), 224 differentially expressed microRNAs (miRNAs), and 12,183 differentially expressed messenger RNAs (mRNAs). WRKY family was the most prominent transcription factor family involved in cold tolerance. Based on the expression patterns and targeted relationships of these differentially expressed RNAs, we discerned five potential ceRNA networks related to low-temperature stress in rice: osa-miR166j-5p from the miR166 family was associated with cold tolerance; osa-miR528-3p and osa-miR156j-3p were linked to stress response; and osa-miR156j-3p was involved in the antioxidant system. In addition, Os03g0152000 in the antioxidant system, as well as Os12g0491800 and Os05g0381400, correlated with the corresponding stress response and circRNAs in the network. A gene sequence difference analysis and phenotypic validation of Os11g0685700 (OsWRKY61) within the WRKY family suggested its potential role in regulating cold tolerance in rice.

Discussion and conclusion

We identified Os11g0685700 (OsWRKY61) as a promising candidate gene for enhancing cold tolerance in japonica rice. The candidate miRNAs, mRNAs, and circRNAs uncovered in this study are valuable targets for researchers and breeders. Our findings will facilitate the development of cold-tolerant rice varieties from multiple angles and provide critical directions for future research into the functions of cold-tolerance-related miRNAs, mRNAs, and circRNAs in rice.

Recent Advances in Low‐Temperature Liquid Electrolyte for Supercapacitors

As one of the key components of supercapacitors, electrolyte is intensively investigated to promote the fast development of the energy supply system under extremely cold conditions. However, high freezing point and sluggish ion transport kinetics for routine electrolytes hinder the application of supercapacitors at low temperatures. Resultantly, the liquid electrolyte should be oriented to reduce the freezing point, accompanied by other superior characteristics, such as large ionic conductivity, low viscosity and outstanding chemical stability. In this review, the intrinsically physical parameters and microscopic structure of low-temperature electrolytes are discussed thoroughly, then the previously reported strategies that are used to address the associated issues are summarized subsequently from the aspects of aqueous and non-aqueous electrolytes (organic electrolyte and ionic liquid electrolyte). In addition, some advanced spectroscopy techniques and theoretical simulation to better decouple the solvation structure of electrolytes and reveal the link between the key physical parameters and microscopic structure are briefly presented. Finally, the further improvement direction is put forward to provide a reference and guidance for the follow-up research.

In Situ Polymerization of Hydrogel Electrolyte on Electrodes Enabling the Flexible All-Hydrogel Supercapacitors with Low-Temperature Adaptability

All-hydrogel supercapacitors are emerging as promising power sources for next-generation wearable electronics due to their intrinsic mechanical flexibility, eco-friendliness, and enhanced safety. However, the insufficient interfacial adhesion between the electrode and electrolyte and the frozen hydrogel matrices at subzero temperatures largely limit the practical applications of all-hydrogel supercapacitors. Here, an all-hydrogel supercapacitor is reported with robust interfacial contact and anti-freezing property, fabricated by in situ polymerizing hydrogel electrolyte onto hydrogel electrodes. The robust interfacial adhesion is developed by the synergistic effect of a tough hydrogel matrix and topological entanglements. Meanwhile, the incorporation of zinc chloride (ZnCl2 ) in the hydrogel electrolyte prevents the freezing of water solvents and endows the all-hydrogel supercapacitor with mechanical flexibility and fatigue resistance across a wide temperature range of 20 °C to -60 °C. Such all-hydrogel supercapacitor demonstrates satisfactory low-temperature electrochemical performance, delivering a high energy density of 11 mWh cm-2 and excellent cycling stability with a capacitance retention of 90% over 10000 cycles at -40 °C. Notably, the fabricated all-hydrogel supercapacitor can endure dynamic deformations and operate well under 2000 tension cycles even at -40 °C, without experiencing delamination and electrochemical failure. This work offers a promising strategy for flexible energy storage devices with low-temperature adaptability.

Insight into the Growth Mechanism of Low-Temperature Synthesis of High-Purity Lithium Slag-Based Zeolite A

The utilization of lithium slag (LS), a solid waste generated during the production of lithium carbonate, poses challenges due to its high sulfur content. This study presents a novel approach to enhancing the value of LS by employing alkali fusion and hydrothermal synthesis techniques to produce zeolite A at low temperatures. The synthesis of high-purity and crystalline lithium-slag-based zeolite A (LSZ) at 60 °C is reported for the first time in this research. The phase, morphology, particle size, and structure of LSZ were characterized by XRD, SEM, TEM, N2 adsorption, and UV Raman spectroscopy, respectively. High-purity and crystalline zeolite A was successfully obtained under hydrothermal conditions of 60 °C, an NaOH concentration of 2.0 mol/L, and a hydrothermal time of 8 h. The samples synthesized at 60 °C exhibited better controllability and almost no byproduct of sodalite occurred compared to zeolite A synthesized at room temperature or conventional temperature (approximately 90 °C). Additionally, the growth mechanism of LSZ was elucidated, challenging the traditional understanding of utilization of lithium and enabling the synthesis of various zeolites at lower temperatures.

Nitrate removal and environmental side-effects controlled by hydraulic residence time in woodchip bioreactors treating cold agricultural drainage water

Denitrifying woodchip bioreactors (WBRs) remove nitrate (NO 3 - ) from agricultural drainage water at field-scale, but their efficacy at cold temperatures remains uncertain. This study shows how hydraulic residence time (HRT) controls NO 3 - removal and environmental side-effects of WBRs at low water temperature under pilot-scale conditions with controlled operation of nine WBRs (94 dm3). Hydraulic properties were assessed by a bromide tracer test, and NO 3 - removal, emissions of nitrous oxide (N2O) and methane (CH4), and losses of dissolved organic carbon (DOC) were measured at HRTs of 5-30 h. Inlet NO 3 - concentrations were increasingly reduced at higher HRTs. The relationship between HRT and the efficiency (%) of NO 3 - removal was linear (R a d j 2  = 0.94), while the relationship between HRT and NO 3 - reduction rates (NRR) was logistic (R a d j 2  = 0.88). Gaseous emissions of N2O were equally low at HRTs of 10-30 h, but higher at 5 h (P < 0.05). Methane fluxes were small, but with consistent emissions at HRTs of 20-30 h and uptake at 5-15 h. HRT had limited effect on effluent DOC concentrations, but strong effect on mass losses that were five-fold higher (320 mg L-1) at the HRT of 5 h than at 30 h. In summary, at cold temperatures HRTs of ≤ 20 h resulted in suboptimal NRR, accelerating DOC losses, and increased risk of N2O losses at least below a threshold HRT of 5-10 h. HRTs of 20-30 h gave maximal NRR, smallest losses of DOC and N2O, but an increased risk of CH4 emissions.

Exploring the Effects of Selenium and Brassinosteroids on Photosynthesis and Protein Expression Patterns in Tomato Plants under Low Temperatures

This study aimed to assess the effects of low-temperature stress on two tomato cultivars (S-22 and PKM-1) treated with 24-epibrassinolide (EBL) and selenium (Se) by determining the changes in the proteomics profiles, growth biomarkers, biochemical parameters, and physiological functions. The growth parameters, photosynthetic traits, and activity of nitrate reductase in the S-22 and PKM-1 plants were markedly reduced by exposure to low temperatures. However, the combined application of EBL and Se under different modes significantly enhanced the aforementioned parameters under stress and non-stress conditions. Exposure to low temperatures increased the activities of the antioxidant enzymes (catalase, peroxidase, and superoxide dismutase) and the proline content of leaves, which were further enhanced by treatment with Se and EBL in both varieties. This research sheds light on the potential for employing exogenous EBL and Se as crucial biochemical tactics to assist tomato plants in surviving low-temperature stress. Moreover, the differentially expressed proteins that were involved in plant metabolism following the combined application of EBL and Se under low-temperature stress were additionally identified. Functional analysis revealed that the Q54YH4 protein plays an active role against plant stressors. The conserved regions in the protein sequences were analyzed for assessing the reliability of plant responses against the external application of EBL and Se under low temperatures.

Tailoring Oxygen Reduction Reaction Kinetics on Perovskite Oxides via Oxygen Vacancies for Low-Temperature and Knittable Zinc-Air Batteries

High kinetics oxygen reduction reaction (ORR) electrocatalysts under low temperature are critical and highly desired for temperature-tolerant energy conversion and storage devices, but remain insufficiently investigated. Herein, oxygen vacancy-rich porous perovskite oxide (CaMnO3 ) nanofibers coated with reduced graphene oxide coating (V-CMO/rGO) are developed as the air electrode catalyst for low-temperature and knittable Zn-air batteries. V-CMO/rGO exhibits top-level ORR activity among perovskite oxides and shows impressive kinetics under low temperature. Experimental and theoretical calculation results reveal that the synergistic effect between metal atoms and oxygen vacancies, as well as the accelerated kinetics and enhanced electric conductivity and mass transfer over the rGO coated nanofiber 3D network contribute to the enhanced catalytic activity. The desorption of ORR intermediate is promoted by the regulated electron filling. The V-CMO/rGO drives knittable and flexible Zn-air batteries under a low temperature of -40 °C with high peak power density of 56 mW cm-2 and long cycle life of over 80 h. This study provides insight of kinetically active catalyst and facilitates the ZABs application in harsh environment.

Turning on Lithium-Sulfur Full Batteries at -10 °C

Lithium-sulfur (Li-S) batteries using Li₂S and Li-free anodes have emerged as a potential high-energy and safe battery technology. Although the operation of Li-S full batteries based on Li₂S has been demonstrated at room temperature, their effective use at a subzero temperature has not been realized due to the low electrochemical utilization of Li₂S. Here, ammonium nitrate (NH₄NO₃) is introduced as a functional additive that allows Li-S full batteries to operate at -10 °C. The polar N-H bonds in the additive alter the activation pathway of Li₂S by inducing the dissolution of the Li₂S surface. Then, Li₂S with an amorphized surface layer undergoes the modified activation process, which consists of the disproportionation and direct conversion reaction, through which Li₂S is efficiently converted into S₈. The Li-S full battery using NH₄NO₃ delivers a reversible capacity and cycling stability over 400 cycles at -10 °C.

Structure and Wear Performance of a Titanium Alloy by Using Low-Temperature Plasma Oxy-Nitriding

To solve the problems of high nitriding temperature and long nitriding time with conventional plasma nitriding technologies, a kind of low-temperature plasma oxy-nitriding technology containing two-stage processes with different ratios of N to O was developed on a TC4 alloy in this paper. A thicker permeation coating can be obtained with this new technology compared to conventional plasma nitriding technology. The reason for this is that the oxygen introduction in the first two-hour oxy-nitriding step can break the continuous TiN layer, which facilitates the quick and deep diffusion of the solution-strengthening elements of O and N into the titanium alloy. Moreover, an inter-connected porous structure was formed under a compact compound layer, which acts as a buffer layer to absorb the external wear force. Therefore, the resultant coating showed the lowest COF values during the initial wear state, and almost no debris and cracks were detected after the wear test. For the treated samples with low hardness and no porous structure, fatigue cracks can easily form on the surface, and bulk peeling-offcan occur during the wear course.

Isocyanate Additives Improve the Low-Temperature Performance of LiNi0.8Mn0.1Co0.1O2||SiOx@Graphite Lithium-Ion Batteries

LiNi_0.8Mn_0.1Co_0.1O₂||SiOx@graphite (NCM811||SiOx@G)-based lithium-ion batteries (LIBs) exhibit high energy density and have found wide applications in various fields, including electric vehicles. Nonetheless, its low-temperature performance remains a challenge. One of the most efficacious strategies to enhance the low-temperature functionality of battery is the development of appropriate electrolytes with low-temperature suitability. Herein, p-tolyl isocyanate (PTI) and 4-fluorophenyl isocyanate (4-FI) are used as additive substances to integrate into the electrolytes to improve the low-temperature performance of the battery. Theoretical calculations and experimental results indicate that PTI and 4-FI can both preferentially generate a stable SEI on the electrode surface, which is beneficial to reduce the interfacial impedance. As a result, the additive, i.e. 4-FI, is superior to PTI in improving the low-temperature performance of the battery due to the optimization of F in the SEI membrane components. At room temperature, the cyclic stability of the NCM811/SiOx@G pouch cell increases from 92.5% (without additive) to 94.2% (with 1% 4-FI) after 200 cycles at 0.5 C. Under the operating temperature of -20 °C, the cyclic stability of the NCM811/SiOx@G pouch cell increases from 83.2% (without additive) to 88.6% (with 1% 4-FI) after 100 cycles at 0.33 C. Therefore, a rational interphase design involving the modification of the additive structure is a cost-effective way to improve the performance of LIBs.

Application of Low Temperature Processed 0-3 Composite Piezoelectric Thick Films in Flexible, Non-planar, High Frequency Ultrasonic Devices

Low-temperature, flexible, 0-3 composite piezoelectric materials can decrease the size, cost, and complexity of high-frequency acoustic devices on temperature sensitive substrates such as those in catheter based ultrasonic devices and acoustooptic sensors. In this paper, the application of low-temperature 0-3 connected composite thick films in flexible, non-planar, high frequency ultrasonic devices is reported. A flexible high-frequency ultrasound transducer and an acousto-optic radio-frequency (RF) field sensor are demonstrated utilizing PZT-based composite thick films. Flexible composite films have been fabricated with thicknesses between 20-100μm utilizing screen-printing, stencil-printing, and dip-coating techniques. Composite films' piezoelectric d33 coefficient is measured, with results between 35-43 pC/N. Ultrasonic transducers utilizing these films demonstrate broadband acoustic response. A composite transducer is fabricated on flexible polyimide and wrapped around a 3mm catheter. Pulse-echo experiments demonstrate viability of these films as both as an actuator and a sensor in flexible devices. The composite material is further dip-coated onto an optical fiber Bragg grating to form a flexible acousto-optic RF field sensor. The sensor demonstrates RF field sensing in the 20-130 MHz range. The results from these experiments indicate significant potential for future flexible, high frequency ultrasonic devices utilizing low temperature 0-3 composite piezoelectric materials on temperature sensitive substrates.

Low-Temperature Loop-Mediated Isothermal Amplification Operating at Physiological Temperature

Loop-mediated isothermal amplification (LAMP) is one of the most widely used isothermal amplification technologies in molecular diagnostics. However, LAMP operates at a high temperature of 65 °C; thus, operating LAMP at a lower temperature is desirable to maximize its usefulness for on-site diagnosis. In this study, we propose a new version of LAMP, termed low-temperature LAMP, which operates at the physiological temperature of 37 °C. Low-temperature LAMP differs from conventional LAMP operating at 65 °C in terms of the concentrations of MgSO₄ and deoxyribonucleoside triphosphates (dNTPs), as well as the lengths of DNA probes, which are crucial for the execution of low-temperature LAMP. Under the optimal conditions, the amplification efficiency of low-temperature LAMP is comparable to that of conventional LAMP. In addition, the ligation reaction at 37 °C, which is necessary to detect actual target nucleic acids, is combined without altering the temperature, enabling the identification of miR-21, a cancer-promoting oncogenic miRNA, with high sensitivity and selectivity. The method described in this paper does not require expensive DNA modifications or special additives and would facilitate the widespread application of LAMP in facility-limited or point-of-care settings, paving the way to improvements in other isothermal-amplification-based techniques.

Weakening Li+ De-solvation Barrier for Cryogenic Li-S Pouch Cells

Li-S batteries hold promise for pushing cell-level energy densities beyond 300 Wh kg^-1 while operating at low temperatures (LTs, below 0 °C). However, the capacity release of existing Li-S batteries at LTs is still barely satisfactory, and there is almost no verification of the practicability of Li-S batteries at LTs in the Ah-level pouch cell. Here, antecedent molecular dynamics (MDs) combined with density functional theory analysis are used to systematically investigate Li⁺ solvation structure in conventional Li-S batteries at LTs, which unprecedentedly reveals the positive correlation between lithium salt concentration and Li⁺ de-solvation barrier, indicating dilute electrolytes can enhance the Li⁺ de-solvation kinetics and thus improve the capacity performance of cryogenic Li-S batteries. These insights derived from theoretical simulations invested Li-S batteries with a 67.34% capacity retention at -40 °C compared to their room temperature performance. In particular, an Ah-level Li-S pouch cell using dilute electrolytes with a high sulfur loading (5.6 mg cm^-2 ) and lean electrolyte condition is fabricated, which delivers a discharge capacity of about 1000 mAh g^-1 and ultra-high energy density of 350 Wh kg^-1 at 0 °C, offering a promising route toward a practical high-energy cryogenic Li-S battery.

Low-Temperature Direct Growth of Nanocrystalline Multilayer Graphene on Silver with Long-Term Surface Passivation

A wide variety of transition metals, including copper and gold, have been successfully used as substrates for graphene growth. On the other hand, it has been challenging to grow graphene on silver, so realistic applications by combining graphene and silver for improved electrode stability and enhanced surface plasmon resonance in organic light-emitting diodes and biosensing have not been realized to date. Here, we demonstrate the surface passivation of silver through the single-step rapid growth of nanocrystalline multilayer graphene on silver via low-temperature plasma-enhanced chemical vapor deposition (PECVD). The effect of the growth time on the graphene quality and the underlying silver characteristics is investigated by Raman spectroscopy, X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy (XPS), and cross-sectional annular dark-field scanning transmission electron microscopy (ADF-STEM). These results reveal nanocrystalline graphene structures with turbostratic layer stacking. Based on the XPS and ADF-STEM results, a PECVD growth mechanism of graphene on silver is proposed. The multilayer graphene also provides excellent long-term protection of the underlying silver surface from oxidation after 5 months of air exposure. This development thus paves the way toward realizing technological applications based on graphene-protected silver surfaces and electrodes as well as hybrid graphene-silver plasmonics.

Current Progress on Methods and Technologies for Catalytic Methane Activation at Low Temperatures

Methane (CH₄ ) is an attractive energy source and important greenhouse gas. Therefore, from the economic and environmental point of view, scientists are working hard to activate and convert CH₄ into various products or less harmful gas at low-temperature. Although the inert nature of CH bonds requires high dissociation energy at high temperatures, the efforts of researchers have demonstrated the feasibility of catalysts to activate CH₄ at low temperatures. In this review, the efficient catalysts designed to reduce the CH₄ oxidation temperature and improve conversion efficiencies are described. First, noble metals and transition metal-based catalysts are summarized for activating CH₄ in temperatures ranging from 50 to 500 °C. After that, the partial oxidation of CH₄ at relatively low temperatures, including thermocatalysis in the liquid phase, photocatalysis, electrocatalysis, and nonthermal plasma technologies, is briefly discussed. Finally, the challenges and perspectives are presented to provide a systematic guideline for designing and synthesizing the highly efficient catalysts in the complete/partial oxidation of CH₄ at low temperatures.

QTL Mapping and a Transcriptome Integrative Analysis Uncover the Candidate Genes That Control the Cold Tolerance of Maize Introgression Lines at the Seedling Stage

Chilling injury owing to low temperatures severely affects the growth and development of maize (Zea mays.L) seedlings during the early and late spring seasons. The existing maize germplasm is deficient in the resources required to improve maize's ability to tolerate cold injury. Therefore, it is crucial to introduce and identify excellent gene/QTLs that confer cold tolerance to maize for sustainable crop production. Wild relatives of maize, such as Z. perennis and Tripsacum dactyloides, are strongly tolerant to cold and can be used to improve the cold tolerance of maize. In a previous study, a genetic bridge among maize that utilized Z. perennis and T. dactyloides was created and used to obtain a highly cold-tolerant maize introgression line (MIL)-IB030 by backcross breeding. In this study, two candidate genes that control relative electrical conductivity were located on MIL-IB030 by forward genetics combined with a weighted gene co-expression network analysis. The results of the phenotypic, genotypic, gene expression, and functional verification suggest that two candidate genes positively regulate cold tolerance in MIL-IB030 and could be used to improve the cold tolerance of cultivated maize. This study provides a workable route to introduce and mine excellent genes/QTLs to improve the cold tolerance of maize and also lays a theoretical and practical foundation to improve cultivated maize against low-temperature stress.

Ultralow-Temperature Aqueous Conductive Polymer-Hydrogen Gas Battery

Hydrogen gas batteries are regarded as one of the most promising rechargeable battery systems for large-scale energy storage applications due to their advantages of high rates and long-term cycle lives. However, the development of cost-effective and low-temperature-tolerant hydrogen gas batteries is highly desirable yet very challenging. Herein, we report a novel conductive polymer-hydrogen gas battery that is suitable for ultralow-temperature energy storage applications and consists of a hydrogen gas anode, a conductive polymer cathode using polyaniline (PANI) or polypyrrole as examples, and protonic acidic electrolytes. The PANI-H₂ battery using 1 M H₂SO₄ as the electrolyte exhibits a capacity of 67 mA h/g, a remarkable rate up to 15 A/g, a Coulombic efficiency around 100%, and an ultra-long life of 10,000 cycles. Using the anti-freezing 9 M H₃PO₄ electrolyte, the PANI-H₂ battery can operate well at temperatures down to -70 °C, which maintains ∼70% of the capacity at room temperature and shows an excellent cycle stability under -60 °C. Benefiting from the fast redox kinetics of both electrodes, this work demonstrates excellent rate performance and low-temperature feasibility of conductive polymer-H₂ batteries, providing a new avenue for further development of low-cost and reliable polymer-H₂ batteries for large-scale energy storage.

Effect of cold storage on development and demographic parameters of Scolothrips longicornis fed on two-spotted spider mite

Cold storage effects on the female predatory thrips Scolothrips longicornis Priesner (Thysanoptera: Thripidae) fed on Tetranychus urticae Koch eggs for different time periods (5, 10, 20 and, 30 days) at 5 or 25 °C (control) on development and life table parameters were examined. Female adult duration and female total longevity were not influenced by the period of cold storage. The minimum mean female total longevity (28.1 ± 0.32 day) was observed in the 30-day treatment. The oviposition period decreased with increasing cold storage duration. All life table parameters of S. longicornis demonstrated a significant difference across treatments. Our results demonstrated that the female adult of S. longicornis could be maintained at 5 °C for 5-days with minimal reduction in the life-history process. This would be beneficial in the storage and mass production of S. longicornis in biocontrol programs involving T. urticae.

The noble metals M (M = Pd, Ag, Au) decorated CeO2catalysts derived from solution combustion method for efficient low-temperature CO catalytic oxidation: effects of different M loading on catalytic performances

The noble metal nanoparticles have attracted attention due to their excellent catalytic performance for CO oxidation at low temperatures. M-CeO₂(M = Pd, Ag, Au) catalysts with different atomic ratios of M/Ce were deposited via solution combustion method. Among them, 3 at% Pd-CeO₂, 5 at% Ag-CeO₂and 1 at% Au-CeO₂catalysts have better catalytic performances. Especially, 5 at% Ag-CeO₂catalyst shows better low-temperature CO oxidation performance. The catalytic activity for CO oxidation follows the follows the following sequence: 5 at% Ag-CeO₂(T₅₀ = 69 °C) > 3 at% Pd-CeO₂(T₅₀ = 99 °C) >1 at% Au-CeO₂(T₅₀ = 115 °C). Meanwhile, the catalysts are characterized by means of powder x-ray diffraction, scanning electron microscope, transmission electron microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy, Brunauer-Emmett-Teller and H₂-TPR. The characterization results show that the 5 at% Ag-CeO₂catalyst has excellent catalytic activity due to the good dispersion of Ag nanoparticles, the specific surface area of the material, and the reduction catalyst between different valence ions. Moreover, the surface of the catalyst enhances the mutual synergy, effectively promotes the generation of oxygen vacancies, and increases the active oxygen content of the catalyst surface. Finally, the catalytic mechanism of M-CeO₂catalysts is summarized.

Effect of Pd-Sensitization on Poisonous Chlorine Gas Detection Ability of TiO2: Green Synthesis and Low-Temperature Operation

Ganoderma lucidum mushroom-mediated green synthesis of nanocrystalline titanium dioxide (TiO₂) is explored via a low-temperature (≤70 °C) wet chemical method. The role of Ganoderma lucidum mushroom extract in the reaction is to release the ganoderic acid molecules that tend to bind to the Ti⁴⁺ metal ions to form a titanium-ganoderic acid intermediate complex for obtaining TiO₂ nanocrystallites (NCs), which is quite novel, considering the recent advances in fabricated gas sensing materials. The X-ray powder diffraction, field emission scanning electron microscopy, Raman spectroscopy, and Brunauer–Emmett–Teller measurements etc., are used to characterize the crystal structure, surface morphology, and surface area of as-synthesized TiO₂ and Pd-TiO₂ sensors, respectively. The chlorine (Cl₂) gas sensing properties are investigated from a lower range of 5 ppm to a higher range of 400 ppm. In addition to excellent response–recovery time, good selectivity, constant repeatability, as well as chemical stability, the gas sensor efficiency of the as-synthesized Pd-TiO₂ NC sensor is better (136% response at 150 °C operating temperature) than the TiO₂ NC sensor (57% at 250 °C operating temperature) measured at 100 ppm (Cl₂) gas concentration, suggesting that the green synthesized Pd-TiO₂ sensor demonstrates efficient Cl₂ gas sensing properties at low operating temperatures over pristine ones.

Melatonin Rescues Photosynthesis and Triggers Antioxidant Defense Response in Cucumis sativus Plants Challenged by Low Temperature and High Humidity

Environmental factors such as low temperature (LT) and high humidity (HH) hinder plant growth and development in plastic tunnels and solar greenhouses in the cold season. In this study, we examined the effect of melatonin (MT) on shoot-based tolerance to LT and HH conditions in cucumber (Cucumis sativus) seedlings and explored its underlying mechanism. LT and HH stress inhibited growth and biomass accumulation, produced leaf chlorosis, led to oxidative stress, lowered chlorophyll and carotenoid contents, reduced photosynthetic and photosystem II (PSII) activities, and increased the level of intercellular carbon dioxide and the non-photochemical quenching of photosystem I (PSI) and PSII. However, foliar application of MT significantly improved the morphological indices and photosynthetic efficiency of cucumber seedlings, which entailed the elevation of electrolyte leakage, lipid peroxidation, and reactive oxygen species accumulation by boosting the antioxidant enzyme defense system under LT and HH conditions. Additionally, the measurement of nitrogen (N), magnesium (Mg), and iron (Fe) contents in roots and leaves showed that MT significantly augmented the nutrient uptake of cucumber seedlings exposed to LT and HH stresses. Furthermore, MT application increased the transcripts levels of genes encoding antioxidant enzymes under LT and HH conditions, whereas treatment with LT and HH suppressed these genes, suggesting that MT application increases the LT and HH tolerance of cucumber seedlings. Overall, our results suggest that MT application increases the tolerance of cucumber seedlings to LT and HH stress by enhancing the plant morphometric parameters, regulating PSI and PSII, and activating the antioxidant defense mechanism. Thus, the exogenous application of MT could be potentially employed as a strategy to improve the LT and HH tolerance of cucumber.

Inorganic Electrolyte for Low-Temperature Aqueous Sodium Ion Batteries

Aqueous sodium ion batteries have received widespread attention due to their great application potential and high safety. However, the serious capacity fading under low temperature dramatically restricts their practical application. Compared to flammable and toxic organic antifreezing additives, addition of common cheap inorganic inert additives to improve low-temperature performance is of interest scientifically. Herein, low-cost calcium chloride is served as antifreezing additive in 1 m NaClO₄ aqueous electrolyte due to its strong interaction with water molecules. The freezing point of the optimized electrolyte is significantly reduced to below -50 °C with an ultrahigh ionic conductivity (7.13 mS cm^-1 ) at -50 °C. All pure inorganic composition of the full battery delivers a high capacity of 74.5 mAh g^-1 under 1 C (1 C = 150 mA g^-1 ) at -30 °C. More importantly, when tested under 10 C at -30 °C, the battery can achieve an ultralong cycling stability of 6000 cycles with no obvious capacity decay, indicating fast Na⁺ transport under low temperature. Significantly, this work provides an easy-to-operate strategy by adding cheap inorganic salt to develop high-performance low-temperature aqueous batteries.

Impact of microbial inoculants combined with humic acid on the fate of estrogens during pig manure composting under low-temperature conditions

To investigate the efficiency of psychrotrophic cellulose-degrading fungal strains (PCDFSs) and estrogen-degrading bacteria (EDBs) combined with humic acid (HA) on estrone (E1) and 17-β-estradiol (E2) degradation, five compost groups (T, HA, EDB, PCDFS, and CK) were prepared and composted for 32 days at 11-14°C. The results indicated that inoculation increased the temperature to 62.2°C and promoted E1 degradation to the lowest level of 100.1 ng/kg, while E2 was undetected from day 16. Metagenomic analysis revealed that inoculation altered the microbial community structure by increasing the abundance of cellulose-degrading fungi, especially Meyerozyma (16.7%) (among PCDFSs), and of estrogen-degrading bacteria, particularly Microbacterium (13.4%) (involved in EDBs). Moreover, inoculation increased the levels (>0.500%) of Gene Ontology (GO) associated with estrogen degradation, like 3-β-hydroxy-delta 5-steroid dehydrogenase and monooxygenase. Redundancy analysis demonstrated that temperature and Microbacterium were positively correlated with estrogen degradation. Structural equation model indicated that temperature and estrogen-degrading bacterial genera exhibited positive, significant (p < 0.001) and direct impacts on estrogen degradation. This is the first study to suggest that applying microbial inoculants and HA could accelerate estrogen degradation during composting in cold regions. The research outcomes offer a practical reference for managing compost safety, thereby decreasing its potential environmental and human health impacts.

A Transcriptomic Analysis of Gonads from the Low-Temperature-Induced Masculinization of Takifugu rubripes

Simple Summary

Our study analyzed the differentiation of transcriptomes in normal and sex-reverse Takifugu rubripes, and screened out 13 differentially expressed genes related to sex differentiation. This is the first report on the gonadal transcriptome of pseudo-males in Takifugu rubripes. Our results provide an important contribution to the molecular mechanism of masculinization in a cultured fish subject to low-temperature treatment.

Abstract

The phenotypic sex of fish is usually plastic. Low-temperature treatment induces the masculinization of Takifugu rubripes, resulting in pseudo-males (PM) with the physiological sex of a male (M) and genetic sex of a female (F). For a comparison of gonadal transcriptomes, we collected gonads from three groups of T. rubripes (F, M, and PM) for high-throughput transcriptome sequencing. The results provided 467,640,218 raw reads (70.15 Gb) and a total of 436,151,088 clean reads (65.43 Gb), with an average length of 150 bp. Only 79 differentially expressed genes (DEGs) were identified between F and PM, whereas 12,041 and 11,528 DEGs were identified between F and M, and PM and M, respectively. According to the functional annotation of DEGs, 13 DEGs related to gonadal development were screened (LOC101066759, dgat1, limk1, fbxl3, col6a3, fgfr3, dusp22b, svil, abhd17b, srgap3, tmem88b, bud4, and mustn10) which might participate in formating PM. A quantitative PCR of the DEGs confirmed the reliability of the RNA-seq. Our results provide an important contribution to the genome sequence resources for T. rubripes and insight into the molecular mechanism of masculinization in a cultured fish subject to low-temperature treatment.

Sub-4 nm Nanodiamonds from Graphene-Oxide and Nitrated Polycyclic Aromatic Hydrocarbons at 423 K

Nanodiamonds are interesting materials from the point of view of their biocompatibility and their chemical, spectroscopic, and mechanical properties. Current synthetic methods for nanodiamonds involve harsh environments, which are potentially hazardous in addition to being expensive. We report a low-temperature (423 K) hydrothermal approach to form nanodiamonds by using graphene-oxide or nitrated polycyclic aromatic hydrocarbons (naphthalene, anthracene, phenanthrene, or pyrene) as a starting material. The reaction products contain single-crystalline or twinned nanodiamonds with average diameters in the 2-3 nm range. Theoretical calculations prove that, at the nanoscale, sub-4 nm nanodiamonds may adopt a structure that is more stable than graphene-oxide and nitrated polycyclic aromatic hydrocarbons. Our findings show that sp² carbon in the polycyclic aromatic precursor can be converted to sp³ carbon under unexpectedly moderate temperature conditions by using nanoscale precursors and thus offer a low-temperature approach for the synthesis of sub-4 nm nanodiamonds.

CDE4 encodes a pentatricopeptide repeat protein involved in chloroplast RNA splicing and affects chloroplast development under low-temperature conditions in rice

Pentatricopeptide repeat (PPR) proteins play important roles in the post-transcriptional modification of organellar RNAs in plants. However, the function of most PPR proteins remains unknown. Here, we characterized the rice (Oryza sativa L.) chlorophyll deficient 4 (cde4) mutant which exhibits an albino phenotype during early leaf development, with decreased chlorophyll contents and abnormal chloroplasts at low-temperature (20°C). Positional cloning revealed that CDE4 encodes a P-type PPR protein localized in chloroplasts. In the cde4 mutant, plastid-encoded polymerase (PEP)-dependent transcript levels were significantly reduced, but transcript levels of nuclear-encoded genes were increased compared to wild-type plants at 20°C. CDE4 directly binds to the transcripts of the chloroplast genes rpl2, ndhA, and ndhB. Intron splicing of these transcripts was defective in the cde4 mutant at 20°C, but was normal at 32°C. Moreover, CDE4 interacts with the guanylate kinase VIRESCENT 2 (V2); overexpression of V2 enhanced CDE4 protein stability, thereby rescuing the cde4 phenotype at 20°C. Our results suggest that CDE4 participates in plastid RNA splicing and plays an important role in rice chloroplast development under low-temperature conditions.

Low-Temperature Fabrication of IZO Thin Film for Flexible Transistors

Solution-processed thin film transistors (TFTs) used in flexible electronics require them to be fabricated under low temperature. Ultraviolet (UV) treatment is an effective method to transform the solution precursors into dense semiconductor films. In our work, high-quality indium zinc oxide (IZO) thin films were prepared from nitrate-based precursors after UV treatment at room temperature. After UV treatment, the structure of IZO thin films was gradually rearranged, resulting in good M–O–M network formation and bonds. TFTs using IZO as a channel layer were also fabricated on Si and Polyimide (PI) substrate. The field effect mobility, threshold voltage (V_th), and subthreshold swing (SS) for rigid and flexible IZO TFTs are 14.3 and 9.5 cm²/Vs, 1.1 and 1.7 V, and 0.13 and 0.15 V/dec., respectively. This low-temperature processed route will definitely contribute to flexible electronics fabrication.

All-Liquid-Phase Reaction Mechanism Enabling Cryogenic Li-S Batteries

The sluggish solid-solid conversion kinetics from Li₂S₄ to Li₂S during discharge is considered the main problem for cryogenic Li-S batteries. Herein, an all-liquid-phase reaction mechanism, where all the discharging intermediates are dissolved in the functional thioether-based electrolyte, is proposed to significantly enhance the kinetics of Li-S battery chemistry at low temperatures. A fast liquid-phase reaction pathway thus replaces the conventional slow solid-solid conversion route. Spectral investigations and molecular dynamics simulations jointly elucidate the greatly enhanced kinetics due to the highly decentralized state of solvated intermediates in the electrolyte. Overall, the battery brings an ultrahigh specific capacity of 1563 mAh g^-1_{sulfur in the cathode} at -60 °C. This work provides a strategy for developing cryogenic Li-S batteries.

MicroRNA Omics Analysis of Camellia sinesis Pollen Tubes in Response to Low-Temperature and Nitric Oxide

Nitric oxide (NO) as a momentous signal molecule participates in plant reproductive development and responds to various abiotic stresses. Here, the inhibitory effects of the NO-dominated signal network on the pollen tube growth of Camellia sinensis under low temperature (LT) were studied by microRNA (miRNA) omics analysis. The results showed that 77 and 71 differentially expressed miRNAs (DEMs) were induced by LT and NO treatment, respectively. Gene ontology (GO) analysis showed that DEM target genes related to microtubules and actin were enriched uniquely under LT treatment, while DEM target genes related to redox process were enriched uniquely under NO treatment. In addition, the target genes of miRNA co-regulated by LT and NO are only located on the cell membrane and cell wall, and most of them are enriched in metal ion binding and/or transport and cell wall organization. Furthermore, DEM and its target genes related to metal ion binding/transport, redox process, actin, cell wall organization and carbohydrate metabolism were identified and quantified by functional analysis and qRT-PCR. In conclusion, miRNA omics analysis provides a complex signal network regulated by NO-mediated miRNA, which changes cell structure and component distribution by adjusting Ca²⁺ gradient, thus affecting the polar growth of the C. sinensis pollen tube tip under LT.

Bacillus cereus Decreases NHE and CLO Exotoxin Synthesis to Maintain Appropriate Proteome Dynamics During Growth at Low Temperature

Cellular proteomes and exoproteomes are dynamic, allowing pathogens to respond to environmental conditions to sustain growth and virulence. Bacillus cereus is an important food-borne pathogen causing intoxication via emetic toxin and/or multiple protein exotoxins. Here, we compared the dynamics of the cellular proteome and exoproteome of emetic B. cereus cells grown at low (16 °C) and high (30 °C) temperature. Tandem mass spectrometry (MS/MS)-based shotgun proteomics analysis identified 2063 cellular proteins and 900 extracellular proteins. Hierarchical clustering following principal component analysis indicated that in B. cereus the abundance of a subset of these proteins—including cold-stress responders, and exotoxins non-hemolytic enterotoxin (NHE) and hemolysin I (cereolysin O (CLO))—decreased at low temperature, and that this subset governs the dynamics of the cellular proteome. NHE, and to a lesser extent CLO, also contributed significantly to exoproteome dynamics; with decreased abundances in the low-temperature exoproteome, especially in late growth stages. Our data therefore indicate that B. cereus may reduce its production of secreted protein toxins to maintain appropriate proteome dynamics, perhaps using catabolite repression to conserve energy for growth in cold-stress conditions, at the expense of virulence.

Modification of V2O5-WO3/TiO2 Catalyst by Loading of MnOx for Enhanced Low-Temperature NH3-SCR Performance

V₂O₅-WO₃/TiO₂ as a commercial selective catalytic reduction (SCR) catalyst usually used at middle-high temperatures was modified by loading of MnO_x for the purpose of enhancing its performance at lower temperatures. Manganese oxides were loaded onto V-W/Ti monolith by the methods of impregnation (I), precipitation (P), and in-situ growth (S), respectively. SCR activity of each modified catalyst was investigated at temperatures in the range of 100–340 °C. Catalysts were characterized by specific surface area and pore size determination (BET), X-ray diffraction (XRD), temperature programmed reduction (TPR), etc. Results show that the loading of MnO_x remarkably enhanced the SCR activity at a temperature lower than 280 °C. The catalyst prepared by the in-situ growth method was found to be most active for SCR.

Characterization of Weissella koreensis SK Isolated from Kimchi Fermented at Low Temperature (around 0 °C) Based on Complete Genome Sequence and Corresponding Phenotype

This study identified lactic acid bacteria (LAB) that play a major role in kimchi fermented at low temperature, and investigated the safety and functionality of the LAB via biologic and genomic analyses for its potential use as a starter culture or probiotic. Fifty LAB were isolated from 45 kimchi samples fermented at -1.5~0 °C for 2~3 months. Weissella koreensis strains were determined as the dominant LAB in all kimchi samples. One strain, W. koreensis SK, was selected and its phenotypic and genomic features characterized. The complete genome of W. koreensis SK contains one circular chromosome and plasmid. W. koreensis SK grew well under mesophilic and psychrophilic conditions. W. koreensis SK was found to ferment several carbohydrates and utilize an alternative carbon source, the amino acid arginine, to obtain energy. Supplementation with arginine improved cell growth and resulted in high production of ornithine. The arginine deiminase pathway of W. koreensis SK was encoded in a cluster of four genes (arcA-arcB-arcD-arcC). No virulence traits were identified in the genomic and phenotypic analyses. The results indicate that W. koreensis SK may be a promising starter culture for fermented vegetables or fruits at low temperature as well as a probiotic candidate.

Low-Temperature Solution Crystallization of Nanostructured Oxides and Thin Films

As an introduction to this themed issue, a critically selected overview of recent progress on the topic of solution methods for the low-temperature crystallization of nanoscale oxide materials is presented. It is focused on the low-temperature solution processing of oxide nanostructures and thin films. Benefits derived from these methods span from minimizing the environmental impact to reducing the fabrication costs. In addition, this topic is regarded as a key objective in the area because it offers a unique opportunity for the use of these materials in areas like flexible electronics, energy conversion and storage, environmental sciences, catalysis, or biomedicine.

Low-Temperature Electroluminescence Excitation Mapping of Excitons and Trions in Short-Channel Monochiral Carbon Nanotube Devices

Single-walled carbon nanotubes as emerging quantum-light sources may fill a technological gap in silicon photonics due to their potential use as near-infrared, electrically driven, classical or nonclassical emitters. Unlike in photoluminescence, where nanotubes are excited with light, electrical excitation of single tubes is challenging and heavily influenced by device fabrication, architecture, and biasing conditions. Here we present electroluminescence spectroscopy data of ultra-short-channel devices made from (9,8) carbon nanotubes emitting in the telecom band. Emissions are stable under current biasing, and no enhanced suppression is observed down to 10 nm gap size. Low-temperature electroluminescence spectroscopy data also reported exhibit cold emission and line widths down to 2 meV at 4 K. Electroluminescence excitation maps give evidence that carrier recombination is the mechanism for light generation in short channels. Excitonic and trionic emissions can be switched on and off by gate voltage, and corresponding emission efficiency maps were compiled. Insights are gained into the influence of acoustic phonons on the line width, absence of intensity saturation and exciton-exciton annihilation, environmental effects such as dielectric screening and strain on the emission wavelength, and conditions to suppress hysteresis and establish optimum operation conditions.

Low temperature selective catalytic reduction of nitric oxide with urea over activated carbon supported metal oxide catalysts

Selective catalytic reduction of nitrogen oxides (SCR) with loaded urea is a method for removing NO under oxygen-rich and low-temperature conditions, which can solve the inhibitory effect of oxygen on the catalyst and the slip of ammonia. In present study, a series of activated carbon (wo-AC, co-AC, cs-AC and nu-AC) supported metal (Mn, Fe, Co, Cu and Zn) oxide catalysts with loading urea were prepared by ultrasonic assisted impregnation. The catalysts were used for NO removal at 50-120°C and characterized by XRD, SEM, GFAAS, EDS, XPS, BET and FTIR techniques. The effects of activated carbon type, loaded active element, metal oxides loading, temperature fluctuation on catalytic activity and the catalytic stability were also studied in this paper. The results indicated that nutshell-based activated carbon was more suitable as a carrier than other activated carbons, and urea-10Mn/nu-AC catalyst yielded a higher NO conversion than other catalysts. Besides, for used activated carbons, the larger specific surface area, more micropores distribution and the larger number of hydroxyl group and cyano terminal group are beneficial to the catalytic process. Moreover, the downward trend of NO conversion with increasing temperature suggested the adsorption of reactant gases played a crucial role in the catalytic process of urea-SCR.

Grazing-angle reflectivity setup for the low-temperature infrared spectroscopy of two-dimensional systems

A new optical setup is described that allows the reflectivity at grazing incidence to be measured, including ultrathin films and two-dimensional electron systems (2DES) down to liquid-helium temperatures, by exploiting the Berreman effect and the high brilliance of infrared synchrotron radiation. This apparatus is well adapted to detect the absorption of a 2DES of nanometric thickness, namely that which forms spontaneously at the interface between a thin film of LaAlO₃ and its SrTiO₃ substrate, and to determine its Drude parameters.

Investigating the Effect of Aggregate Characteristics on the Macroscopic and Microscopic Fracture Mechanisms of Asphalt Concrete at Low-Temperature

The low-temperature crack of asphalt concrete is considered to be one of the main deteriorations in asphalt pavements. However, there have been few studies on the composite effects of the aggregate characteristics and fracturing modes on the low-temperature cracking of asphalt concrete. Hence, the edge cracked semi-circular bend tests and the discrete element modeling approaches are combined to investigate the effect of the aggregate contents, aggregate morphological features and aggregate distributions on the fracture behavior of asphalt concrete in different fracturing modes at different temperatures. The results show that the fracture toughness and the crack extended time reduce with the increasing aggregate orientation and flatness and the decreased aggregate content. The effect of aggregate flatness is nonlinear, and its reduction trend grows gradually with the increasing flatness. The total number of failed contacts is reduced with the increasing aggregate orientation and flatness, particularly at 10 °C. The number of failed contacts that occurred in the aggregate–mastic interface in Quasi-Mode II fracturing is slightly higher than that in other fracturing modes. The aggregate distribution in the crack initiation zone greatly influenced the crack resistance, particularly at 10 °C. The research is beneficial to better understand the fracture mechanisms of asphalt concrete at low-temperature.

Low-Temperature Thermally Annealed Niobium Oxide Thin Films as a Minimally Color Changing Ion Storage Layer in Solution-Processed Polymer Electrochromic Devices

The limited availability of solution-processable ion storage materials, both inorganic and organic, hinders the adoption of roll-to-roll manufacturing for polymer electrochromic devices (ECDs). The n-type transition metal oxides are known for their ion storage properties. However, the fabrication methods of their amorphous metal oxide thin films typically involve sputtering, thermal deposition, electrical deposition, or sol-gel deposition followed by high-temperature thermal annealing (>300 °C), thus making them incompatible for low-cost roll-to-roll manufacturing on flexible substrates. In this study, we report the synthesis of amorphous niobium oxide(a-Nb₂O₅) thin films from sol-gel precursors through the combination of photoactivation and low-temperature thermal annealing (150 °C). Coupled with p-type electrochromic polymers (ECPs), solution-processed a-Nb₂O₅ thin films were evaluated as a minimally color changing counter electrode (MCC-CE) material for electrochromic devices. We found that ultraviolet ozone (UVO) treated and 150 °C thermally annealed (UVO-150 °C) a-Nb₂O₅ thin films show excellent electrochemical properties and cycling stability. Notably, a-Nb₂O₅/ECP-magenta ECD has a high optical contrast of ∼70% and a fast switching time (bleaching and coloring time of 1.6 and 0.5 s for reaching 95% of optical contrast). In addition, the ECD demonstrates a high coloration efficiency of ∼849.5 mC cm^-2 and a long cycling stability without a noticeable decay up to 3000 cycles.

Bismuth Islands for Low-Temperature Sodium-Beta Alumina Batteries

Wetting of the liquid metal on the solid electrolyte of a liquid metal battery controls the operating temperature and performance of the battery. Liquid sodium electrodes are particularly attractive because of their low cost, natural abundance, and geological distribution. However, they wet poorly on a solid electrolyte near its melting temperature, limiting their widespread suitability for low-temperature batteries to be used for large-scale energy storage systems. Herein, we develop an isolated metal-island strategy that can improve sodium wetting in sodium-beta alumina batteries that allows operation at lower temperatures. Our results suggest that in situ heat treatment of a solid electrolyte followed by bismuth deposition effectively eliminates oxygen and moisture from the surface of the solid electrolyte, preventing the formation of an oxide layer on the liquid sodium, leading to enhanced wetting. We also show that employing isolated bismuth islands significantly improves cell performance, with cells retaining 94% of their charge after the initial cycle, an improvement over cells without bismuth islands. These results suggest that coating isolated metal islands is a promising and straightforward strategy for the development of low-temperature sodium-β alumina batteries.

Low-Temperature Performance and Damage Constitutive Model of Eco-Friendly Basalt Fiber⁻Diatomite-Modified Asphalt Mixture under Freeze⁻Thaw Cycles

Asphalt pavement located in seasonal frozen regions usually suffers low-temperature cracking and freeze–thaw damage. For this reason, diatomite and basalt fiber were used to modify asphalt mixtures. An indirect tensile test was used to determine the low-temperature performance of the asphalt mixture. The influences of freeze–thaw (F–T) cycles on strength, tensile failure strain, stiffness modulus, and strain energy density were analyzed. The variation of the stress–strain curve under F–T cycles was analyzed. The stress–strain curve was divided into a linear zone and nonlinear zone. The linear zone stress ratio and linear zone strain ratio were proposed as indexes to evaluate the nonlinear characteristics of the stress–strain curve. The results show that the basalt fiber–diatomite-modified asphalt mixture had better low temperature crack resistance and antifreeze–thaw cycles capacity compared to the control asphalt mixture. The F–T cycles made the nonlinear characteristics of the stress–strain relationship of the asphalt mixture remarkable, and also decreased the linear zone stress ratio and linear zone strain ratio. The damage constitutive model established in this paper can describe the stress–strain relationship after F–T damage well.

Recent Advances of Solution-Processed Metal Oxide Thin-Film Transistors

Solution-processed metal oxide thin-film transistors (TFTs) are considered as one of the most promising transistor technologies for future large-area flexible electronics. This work surveys the recent advances in solution-processed metal oxide TFTs, including n-type oxide semiconductors, oxide dielectrics, and p-type oxide semiconductors. We first deliver a review on the history and present status of metal oxide TFTs. Then, we present the recent progress in solution-processed n-type oxide semiconductors, with a special focus on low-temperature and large-area solution-based approaches as well as emerging nondisplay applications. Next, we give a detailed analysis of the state-of-the-art solution-processed oxide dielectrics for low-power electronics. We further discuss the recent advances in solution-based p-type oxide semiconductors, which will enable the highly desirable future low-cost large-area complementary circuits. Finally, we draw conclusions and outline the perspectives over the research field.

Low-Temperature Sulfidic-Ice Microbial Communities, Borup Fiord Pass, Canadian High Arctic

A sulfur-dominated supraglacial spring system found at Borup Fiord Pass (BFP), Ellesmere Island, Nunavut, Canada, is a unique sulfur-on-ice system expressed along the toe of a glacier. BFP has an intermittent flowing, subsurface-derived, glacial spring that creates a large white-yellow icing (aufeis) that extends down-valley. Over field campaigns in 2014, 2016, and 2017, numerous samples were collected and analyzed for both microbial community composition and aqueous geochemistry. Samples were collected from multiple site types: spring discharge fluid, aufeis (spring-derived ice), melt pools with sedimented cryoconite material, and mineral precipitate scrapings, to probe how microbial communities differed between site types in a dynamic freeze/thaw sulfur-rich system. Dissolved sulfate varied between 0.07 and 11.6 mM and was correlated with chloride concentrations, where the fluids were saltiest among spring fluids. The highest sulfate samples exhibited high dissolved sulfide values between 0.22 and 2.25 mM. 16S rRNA gene sequencing from melt pool and aufeis samples from the 2014 campaign were highly abundant in operational taxonomic units (OTUs) closely related to sulfur-oxidizing microorganisms (SOM; Sulfurimonas, Sulfurovum, and Sulfuricurvum). Subsequent sampling 2 weeks later had fewer SOMs and showed an increased abundance of the genus Flavobacterium. Desulfocapsa, an organism that specializes in the disproportionation of inorganic sulfur compounds was also found. Samples from 2016 and 2017 revealed that microorganisms present were highly similar in community composition to 2014 samples, primarily echoed by the continued presence of Flavobacterium sp. Results suggest that while there may be acute events where sulfur cycling organisms dominate, a basal community structure appears to dominate over time and site type. These results further enhance our knowledge of low-temperature sulfur systems on Earth, and help to guide the search for potential life on extraterrestrial worlds, such as Europa, where similar low-temperature sulfur-rich conditions may exist.

Nickel Sulfides Decorated SiC Foam for the Low Temperature Conversion of H₂S into Elemental Sulfur

The selective oxidation of H₂S to elemental sulfur was carried out on a NiS₂/SiC^foam catalyst under reaction temperatures between 40 and 80 °C using highly H₂S enriched effluents (from 0.5 to 1 vol.%). The amphiphilic properties of SiC foam provide an ideal support for the anchoring and growth of a NiS₂ active phase. The NiS₂/SiC composite was employed for the desulfurization of highly H₂S-rich effluents under discontinuous mode with almost complete H₂S conversion (nearly 100% for 0.5 and 1 vol.% of H₂S) and sulfur selectivity (from 99.6 to 96.0% at 40 and 80 °C, respectively), together with an unprecedented sulfur-storage capacity. Solid sulfur was produced in large aggregates at the outer catalyst surface and relatively high H₂S conversion was maintained until sulfur deposits reached 140 wt.% of the starting catalyst weight. Notably, the spent NiS₂/SiC^foam catalyst fully recovered its pristine performance (H₂S conversion, selectivity and sulfur-storage capacity) upon regeneration at 320 °C under He, and thus, it is destined to become a benchmark desulfurization system for operating in discontinuous mode.

All-Solution-Processed Metal-Oxide-Free Flexible Organic Solar Cells with Over 10% Efficiency

All-solution-processing at low temperatures is important and desirable for making printed photovoltaic devices and also offers the possibility of a safe and cost-effective fabrication environment for the devices. Herein, an all-solution-processed flexible organic solar cell (OSC) using poly(3,4-ethylenedioxythiophene):poly-(styrenesulfonate) electrodes is reported. The all-solution-processed flexible devices yield the highest power conversion efficiency of 10.12% with high fill factor of over 70%, which is the highest value for metal-oxide-free flexible OSCs reported so far. The enhanced performance is attributed to the newly developed gentle acid treatment at room temperature that enables a high-performance PEDOT:PSS/plastic underlying substrate with a matched work function (≈4.91 eV), and the interface engineering that endows the devices with better interface contacts and improved hole mobility. Furthermore, the flexible devices exhibit an excellent mechanical flexibility, as indicated by a high retention (≈94%) of the initial efficiency after 1000 bending cycles. This work provides a simple route to fabricate high-performance all-solution-processed flexible OSCs, which is important for the development of printing, blading, and roll-to-roll technologies.

Low Temperature-Derived 3D Hexagonal Crystalline Fe3O4 Nanoplates for Water Purification

Fe₃O₄ nanoplates were fabricated by an anodic oxidation process and a subsequent water assisted crystallization process at low temperature, which was found to be very efficient and environmentally friendly. The as-prepared Fe₃O₄ nanoplates have hexagonal outlines with a thickness of about 20 nm. Tremendous grooves were distributed on the entire surfaces of the nanoplates, making the two-dimension nanoplates have a unique 3D morphology. Transmission electron microscopy results confirmed that the single-crystalline nature of the nanoplates was well maintained. Owing to the unique structures and porous morphologies, the as-prepared 3D nanoplates show excellent ability for absorbing solar energy and absorbing organic pollutants, which can be utilized for cleaning up water. Moreover, the Fe₃O₄ nanoplates show good magnetic properties that enable them to be easily collected and recycled. We believe this study will inspire the application of Fe₃O₄ nanoplates with 3D structures in energy and environmental areas.

Contribution of low-temperature single-molecule techniques to structural issues of pigment-protein complexes from photosynthetic purple bacteria

As the electronic energies of the chromophores in a pigment-protein complex are imposed by the geometrical structure of the protein, this allows the spectral information obtained to be compared with predictions derived from structural models. Thereby, the single-molecule approach is particularly suited for the elucidation of specific, distinctive spectral features that are key for a particular model structure, and that would not be observable in ensemble-averaged spectra due to the heterogeneity of the biological objects. In this concise review, we illustrate with the example of the light-harvesting complexes from photosynthetic purple bacteria how results from low-temperature single-molecule spectroscopy can be used to discriminate between different structural models. Thereby the low-temperature approach provides two advantages: (i) owing to the negligible photobleaching, very long observation times become possible, and more importantly, (ii) at cryogenic temperatures, vibrational degrees of freedom are frozen out, leading to sharper spectral features and in turn to better resolved spectra.

Effect of Low Temperature on Charge Transport in Operational Planar and Mesoporous Perovskite Solar Cells

Low-temperature optoelectrical studies of perovskite solar cells using MAPbI₃ and mixed-perovskite absorbers implemented into planar and mesoporous architectures reveal fundamental charge transporting properties in fully assembled devices operating under light bias. Both types of devices exhibit inverse correlation of charge carrier lifetime as a function of temperature, extending carrier lifetimes upon temperature reduction, especially after exposure to high optical biases. Contribution of bimolecular channels to the overall recombination process should not be overlooked because the density of generated charge surpasses trap-filling concentration requirements. Bimolecular charge recombination coefficient in both device types is smaller than Langevin theory prediction, and its mean value is independent of the applied illumination intensity. In planar devices, charge extraction declines upon MAPbI₃ transition from a tetragonal to an orthorhombic phase, indicating a connection between the trapping/detrapping mechanism and temperature. Studies on charge extraction by linearly increasing voltage further support this assertion, as charge carrier mobility dependence on temperature follows multiple-trapping predictions for both device structures. The monotonously increasing trend following the rise in temperature opposes the behavior observed in neat perovskite films and indicates the importance of transporting layers and the effect they have on charge transport in fully assembled solar cells. Low-temperature phase transition shows no pattern of influence on thermally activated electron/hole transport.

Exciton Recombination in Formamidinium Lead Triiodide: Nanocrystals versus Thin Films

The optical properties of the newly developed near-infrared emitting formamidinium lead triiodide (FAPbI₃ ) nanocrystals (NCs) and their polycrystalline thin film counterpart are comparatively investigated by means of steady-state and time-resolved photoluminescence. The excitonic emission is dominant in NC ensemble because of the localization of electron-hole pairs. A promisingly high quantum yield above 70%, and a large absorption cross-section (5.2 × 10^-13 cm^-2 ) are measured. At high pump fluence, biexcitonic recombination is observed, featuring a slow recombination lifetime of 0.4 ns. In polycrystalline thin films, the quantum efficiency is limited by nonradiative trap-assisted recombination that turns to bimolecular at high pump fluences. From the temperature-dependent photoluminescence (PL) spectra, a phase transition is clearly observed in both NC ensemble and polycrystalline thin film. It is interesting to note that NC ensemble shows PL temperature antiquenching, in contrast to the strong PL quenching displayed by polycrystalline thin films. This difference is explained in terms of thermal activation of trapped carriers at the nanocrystal's surface, as opposed to the exciton thermal dissociation and trap-mediated recombination, which occur in thin films at higher temperatures.

A Bacteria-Based Self-Healing Cementitious Composite for Application in Low-Temperature Marine Environments

The current paper presents a bacteria-based self-healing cementitious composite for application in low-temperature marine environments. The composite was tested for its crack-healing capacity through crack water permeability measurements, and strength development through compression testing. The composite displayed an excellent crack-healing capacity, reducing the permeability of cracks 0.4 mm wide by 95%, and cracks 0.6 mm wide by 93% following 56 days of submersion in artificial seawater at 8 °C. Healing of the cracks was attributed to autogenous precipitation, autonomous bead swelling, magnesium-based mineral precipitation, and bacteria-induced calcium-based mineral precipitation in and on the surface of the bacteria-based beads. Mortar specimens incorporated with beads did, however, exhibit lower compressive strengths than plain mortar specimens. This study is the first to present a bacteria-based self-healing cementitious composite for application in low-temperature marine environments, while the formation of a bacteria-actuated organic⁻inorganic composite healing material represents an exciting avenue for self-healing concrete research.