Piezo-Catalytic Effect on the Enhancement of the Ultra-High Degradation Activity in the Dark by Single- and Few-Layers MoS2 Nanoflowers

Single- and few-layer MoS2 nanoflowers are first discovered to have a piezo-catalyst effect, exhibiting an ultra-high degradation activity in the dark by introducing external mechanical strains. The degradation ratio of the Rhodamine-B dye solution reaches 93% within 60 s under ultrasonic-wave assistance in the dark.

ZnO quantum dots-decorated ZnO nanowires for the enhancement of antibacterial and photocatalytic performances

We demonstrate highly antibacterial activities for killing off Staphylococcus aureus and Escherichia coli using ZnO nanowires decorated with ZnO quantum dots (so-called ZnO QDs/NWs) under visible-light irradiation and dark conditions. The average size of the ZnO QDs is in the range of 3-5 nm; these were uniformly dispersed on the ZnO nanowires' surface to form the ZnO QDs/NWs. A significant blue-shift effect was observed using photoluminescence (PL) spectra. The size of the ZnO QDs is strongly dependent on the material's synthesis time. The ZnO QDs/NWs exhibited an excellent photocatalytic activity under visible-light irradiation. The ZnO QDs' active sites (i.e. the O-H bond and Zn(2+)) accelerate the photogenerated-carrier migration from the QDs to the NWs. As a consequence, the electrons reacted with the dissolved oxygen to form oxygen ions and produced hydroperoxyl radicals to enhance photocatalytic activity. The antibacterial activities (as indicated by R-factor-inhibiting activity) of the ZnO QDs/NWs for killing off Staphylococcus aureus and Escherichia coli is around 4.9 and 5.5 under visible-light irradiation and dark conditions, respectively. The hydroxyl radicals served as an efficient oxidized agent for decomposing the organic dye and microorganism species. The antibacterial activities of the ZnO QDs/NWs in the dark may be attributed to the Zn(2+) ions that were released from the ZnO QDs and infused into the microbial solution against the growth of bacteria thus disrupting the microorganism. The highly antibacterial and photocatalytic activity of the ZnO QDs/NWs can be well implanted on a screen window, thus offering a promising solution to inhibit the spread of germs under visible-light and dark conditions.

The surface plasmon resonance effect on the enhancement of photodegradation activity by Au/ZnSn(OH)6 nanocubes

This is the first report on the photocatalytic activity with a combination of the surface plasmon resonance effect through Au/ZnSn(OH)₆ nanocubes. The nanocubes have been used for preparing hybrid coating screens, which exhibited excellent mechanical desirable durability and extended their feasible application in our daily lives.

[Establishment of a FVB/N mouse model of cardiac hypertrophy by isoprenaline]

OBJECTIVE

To investigate the condition of isoprenaline (ISO)-induced cardiac hypertrophy in the FVB/N mouse.

METHODS

ISO (30 mg/kg/d) was administered either by daily subcutaneous injection, or by continuous infusion via an implanted osmotic minipump. The mice in each mode of administration were randomly divided into two groups. For subcutaneous injection: the mice received ISO or saline through daily subcutaneous injection for 2 weeks. The mice for minipump: the mice received continuous infusion of ISO via an implanted osmotic minipump for 2 weeks, or received sham operation as the control to mimipump. The ratio of heart weight to tibia length (HW/TI), the diastolic left ventricular posterior wall thickness (dLVPW) were used to indicate cardiac hypertrophy. Interstitial fibrosis was examined with picrosirius red staining.

RESULTS

ISO (30 mg/kg/d) administered by daily subcutaneous injection did not lead to cardiac hypertrophy or fibrosis in the FVB/N mice, and 50% of the mice died before the end point. The mice receiving ISO via minipumps showed significant increase in HW/TI [(10.60±0.40 ) mg/mm vs. (7.93±0.19) mg/mm,P<0.001] and dLVPW [(0.87±0.03) mm vs. (0.68±0.06)mm,P=0.0116]. ISO administered via minipumps did not induce cardiac fibrosis. All the mice in this group survived to the end point.

CONCLUSION

ISO (30 mg/kg/d) administered by continuous infusion via a minipump for 2 weeks can lead to significant cardiac hypertrophy.

Thermally pressure-induced partial structural phase transitions in core-shell InSb-SiO2 nanoballs/microballs: characterization, size and interface effect

Core-shell InSb-SiO(2) nanoballs/microballs were synthesized on a Si substrate by carbonthermal reactions at a temperature of 900 °C. High-resolution transmission microscopy (HRTEM) images revealed that the surfaces of the InSb nanoballs/microballs were covered by amorphous SiO(2) layers. On the basis of our theoretical calculation, the thermal expansion coefficient (TEC) of the InSb crystals is ten times higher than that of the SiO(2) shell. Therefore, the SiO(2) serves as a constraining shell for the InSb core so that the compressive stress of ∼-94 MPa can accumulate in the InSb core while a tensile stress of 196 MPa forms in the SiO(2) shell. The thermal excitation accumulated compressive stress in the InSb core, causing a partial structural phase transition from a cubic zinc-blende structure to a hexagonal wurtzite structure. Many lattice defects, such as stacking faults and Moiré fringes, have been observed on the surface of the InSb core. In situ temperature-dependent XRD patterns showed that a reversible InSb hexagonal (002) peak appeared and disappeared as the temperature increased and decreased at a transit point of 200 °C, respectively. As the temperature increased, the XRD diffraction peaks of the InSb wurtzite phase shifted significantly to lower angles because of the formation of compressive stress in the InSb nanoballs. The pressure-induced partial structural phase transitions of the nanostructured InSb occurred at -94 MPa of the compressive stress. This is the first report of this value, which is the lowest value in the pressure-induced phase transition of the nanostructure InSb from the cubic zinc-blende structure to the hexagonal wurtzite structure.

Stretta radiofrequency for gastroesophageal reflux disease-related respiratory symptoms: a prospective 5-year study

AIM

The aim of the present study was to prospectively evaluate the Stretta radiofrequency (RF) treatment for gastroesophageal reflux disease (GERD) -related respiratory symptoms over a 5-years follow-up period.

METHODS

A total of 132 patients underwent the Stretta procedure between April 2007 and February 2009; 122 of the patients (92.4%) completed the 5-year follow-up. Symptom scores and PPI usage were evaluated at baseline, 6 months, 1 year, 3 years and 5 years after treatment.

RESULTS

A total of 122 patients (age, 51.7 ± 13.0 years, M:F, 52: 70) were followed up for 5 years and their outcomes were analyzed. At 5 years after treatment, the symptom scores were significantly reduced (heartburn score, from 5.67 ± 1.52 to 2.41 ± 1.13; regurgitation score, from 5.43 ± 1.66 to 2.27 ± 1.33; chest pain score, from 4.45 ± 1.47 to 2.40 ± 0.88; cough score, from 6.62 ± 1.73 to 3.14 ± 1.43; and asthma score, from 6.83 ± 1.46 to 3.26 ± 1.53, P<0.001). Moreover, 56.6% of the patients were completely off PPIs.

CONCLUSION

Stretta RF significantly improves the symptoms and reduces PPI usage at 5 years. Therefore, it is a viable, effective, and minimally invasive endoluminal procedure for patients with GERD-related respiratory symptoms.

Ultrahigh responsivity and external quantum efficiency of an ultraviolet-light photodetector based on a single VO₂ microwire

We demonstrated a single microwire photodetector first made using a VO2 microwire that exhibted high responsivity (Rλ) and external quantum efficiency (EQE) under varying light intensities. The VO2 nanowires/microwires were grown and attached on the surface of the SiO2/Si(100) substrate. The SiO2 layer can produce extremely low densities of long VO2 microwires. An individual VO2 microwire was bonded onto the ends using silver paste to fabricate a photodetector. The high-resolution transmission electron microscopy image indicates that the nanowires grew along the [100] axis as a single crystal. The critical parameters, such as Rλ, EQE, and detectivity, are extremely high, 7069 A W(-1), 2.4 × 10(10)%, and 1.5 × 10(14) Jones, respectively, under a bias of 4 V and an illumination intensity of 1 μW cm(-2). The asymmetry in the I-V curves results from the unequal barrier heights at the two contacts. The photodetector has a linear I-V curve with a low dark current while a nonlinear curves was observed under varing light intensities. The highly efficient hole-trapping effect contributed to the high responsivity and external quantum efficiency in the metal-oxide nanomaterial photodetector. The responsivity of VO2 photodetector is 6 and 4 orders higher than that of graphene (or MoS2) and GaS, respectively. The findings demonstrate that VO2 nanowire/microwire is highly suitable for realizing a high-performance photodetector on a SiO2/Si substrate.

Laparoscopic Nissen fundoplication is more effective in treating patients with GERD-related chronic cough than Stretta radiofrequency

AIM

Chronic cough is the most common extra-esophageal manifestation of gastroesophageal reflux disease (GERD). This study aimed to retrospectively analyze outcomes in patients with GERD-related cough following laparoscopic Nissen fundoplication (LNF) and Stretta radiofrequency (RF) respectively.

METHODS

Medical charts of 83 patients with GERD-related cough that underwent LNF or Stretta RF between 2007 and 2012 were retrieved. Symptom scores (heartburn, regurgitation and cough) and proton pump inhibitors (PPIs) usages were evaluated.

RESULTS

A total of 83 patients with GERD-related cough underwent LNF (N.=35) and Stretta RF (N.=48), and were followed up 36.78 ± 16.12 months (range 13-55 months). During the follow-up, the post-treatment scores were statistically lower as compared with the pre-treatment scores in both groups, while the cough improvement after Stretta was significantly lower than that after LNF (P<0.001). Besides, 27 (77.1%) patients achieved complete PPI therapy independence after LNF, comparing with 27 (65.1%) after Stretta (P<0.05). No significant differences in post-treatment complications were observed except for the abdominal distention.

CONCLUSION

Even though laparoscopic Nissen fundoplication and Stretta are capable of controlling GERD-related cough effectively and safely in selected patients, laparoscopic Nissen fundoplication could improve more in symptoms and PPI elimination.

Prevalence and genetic characterization of Toxoplasma gondii infection in bats in southern China

Toxoplasma gondii can infect a wide variety of warm-blooded animals, including bats. Limited information on T. gondii infection in bats is available in China. The objective of the present study was to determine prevalence and genetic diversity of T. gondii infection in bats in southern China. A total of 608 bats representing 12 species, including 120 Aselliscus stoliczkanus, 59 Myotis chinensis, 11 Miniopterus schreibersii, 53 Rhinolophus affinis, 32 Rhinolophus pusillus, 81 Hipposideros armiger, 28 Hipposideros fulvus, 32 Cynopterus brachyotis, 14 Cynopterus sphinx, 45 Eonycteris spelaea, 109 Hipposideros larvatus, and 24 Taphozous melanopogon, were collected from Yunnan and Guangxi provinces, southern China. They were examined for the presence of T. gondii DNA by amplification of the B1 gene using a nested PCR, and the positive samples were genotyped at 11 genetic loci (SAG1, 5'- and 3'-SAG2, alternative SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico) using multilocus polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology. Fifty-nine (9.7%) of these bats were detected positive by PCR but only five of these positive DNA samples were completely typed at all loci; of which 4 samples, 2 from A. stoliczkanus, and 2 from H. larvatus, belonged to ToxoDB Genotype #10, and the other one from H. larvatus was identified as ToxoDB Genotype #9 (http://toxodb.org/toxo/). To our knowledge, this is the first report of molecular detection and genetic characterization of T. gondii infection in bats in China. The results show that these bats are potential reservoirs for T. gondii transmission, which may pose a threat to human health.

Ultrafine ZnO nanoparticles/nanowires synthesized on a flexible and transparent substrate: formation, water molecules, and surface defect effects

The ultrafine ZnO nanoparticles/nanowires were successfully synthesized on a flexible and transparent substrate by an ultraviolet-light decomposition process. We demonstrate that water molecules can affect the morphology of ZnO nanostructures. An ultraviolet lamp (λ ~ 380 nm, 75 mW cm(-2)) can be used to irradiate Zn(AcAc)2 and Zn(AcAc)2·H2O precursors, which rapidly synthesize ZnO nanoparticles and nanowires, respectively. High-resolution transmission electron microscopy (HRTEM) images and a selected-area electron diffraction pattern revealed that the single-crystal nanoparticles were comprised of wurtzite structure ZnO. The nanowires consisted of ultrafine nanoparticles. On the basis of the Debye-Scherrer formula, the particle size of ZnO was calculated as ~6-9 nm. The more water molecules the precursor had, the more OH(-) and Zn[(OH)4](2-) it put out. Moreover, due to the Zn[(OH)4](2-) and Zn(OH)2 species formed on the surface of the ZnO nanocrystals, they facilitated the one-dimensional nanowires during the crystal growth process. On the basis of our investigations, oxygen vacancies, hydroxyl, and zinc hydroxide all acted as key components in the formation processes that determined photoresponsive properties.

Self-powered pendulum and micro-force active sensors based on a ZnS nanogenerator

A pendulum and micro-force active sensors have been first made from zinc sulfur nanowires based nanogenerator. The ZnS nanogenerator can be self-powered to trace a simple harmonic motion of a pendulum that released from different angle. A various momentums from 0.077 N s to 0.177 N s were able to detect owing to the output voltage and current of the ZnS nanogenerator were proportional to the momentum.

BaTiO3 Nanotubes-Based Flexible and Transparent Nanogenerators

We have developed a simple, cost-effective, and scalable approach to fabricate a piezoelectric nanogenerator (NG) with stretchable and flexible characteristics using BaTiO3 nanotubes, which were synthesized by the hydrothermal method. The NG was fabricated by making a composite of the nanotubes with polymer poly(dimethylsiloxane) (PDMS). The peak open-circuit voltage and short-circuit current of the NG reached a high level of 5.5 V and 350 nA (current density of 350 nA/cm(2)), respectively. It was used to directly drive a commercial liquid crystal display. The BaTiO3 nanotubes/PDMS composite is highly transparent and useful for a large-scale (11 × 11 cm) fabrication of lead-free piezoelectric NG.

Flexible and transparent nanogenerators based on a composite of lead-free ZnSnO3 triangular-belts

A flexible and transparent lead-free triangular-belt ZnSnO(3) nanogenerator is demonstrated. When a mechanical deformation of ≈0.1% is applied to the triangular-belt ZnSnO(3) nanogenerator, the output voltage and current reached 5.3 V and 0.13 μA, respectively, which indicated a maximum output power density of ≈11 μW·cm(-3). This is the highest output power that has been demonstrated by lead-free ZnSnO(3) triangular-belts.

Dynamic QTL analysis for fruit lycopene content and total soluble solid content in a Solanum lycopersicum x S. pimpinellifolium cross

Fruit lycopene content and total soluble solid content are important factors determining fruit quality of tomatoes; however, the dynamic quantitative trait loci (QTL) controlling lycopene and soluble solid content have not been well studied. We mapped the chromosomal regions controlling these traits in different periods in F(2:3) families derived from a cross between the domestic and wild tomato species Solanum lycopersicum and S. pimpinellifolium. Fifteen QTLs for lycopene and soluble solid content and other related traits analyzed at three different fruit ripening stages were detected with a composite interval mapping method. These QTLs explained 7-33% of the individual phenotypic variation. QTLs detected in the color-changing period were different from those detected in the other two periods. On chromosome 1, the soluble solid content QTL was located in the same region during the color-changing and full-ripe periods. On chromosome 4, the same QTL for lycopene content was found during the color-changing and full-ripe periods. The QTL for lycopene content on chromosome 4 co-located with the QTL for soluble solid content during the full-ripe period. Co-location of lycopene content QTL and soluble solid content QTLs may be due to pleiotropic effects of a single gene or a cluster of genes via physiological relationships among traits. On chromosome 9, the same two QTLs for lycopene content at two different fruit ripening periods may reflect genes controlling lycopene content that are always expressed in tomato fruit development.

Single micro/nanowire pyroelectric nanogenerators as self-powered temperature sensors

We demonstrated the first application of a pyroelectric nanogenerator as a self-powered sensor (or active sensor) for detecting a change in temperature. The device consists of a single lead zirconate titanate (PZT) micro/nanowire that is placed on a thin glass substrate and bonded at its two ends, and it is packaged by polydimethylsiloxane (PDMS). By using the device to touch a heat source, the output voltage linearly increases with an increasing rate of change in temperature. The response time and reset time of the fabricated sensor are about 0.9 and 3 s, respectively. The minimum detecting limit of the change in temperature is about 0.4 K at room temperature. The sensor can be used to detect the temperature of a finger tip. The electricity generated under a large change in temperature can light up a liquid crystal display (LCD).

Thermoelectric nanogenerators based on single Sb-doped ZnO micro/nanobelts

We demonstrate a thermoelectric nanogenerator (NG) made from a single Sb-doped ZnO micro/nanobelt that generates an output power of about 1.94 nW under a temperature difference of 30 K between the two electrodes. A single Sb-doped ZnO microbelt was bonded at its ends on a glass substrate as a NG, which can give an output voltage of 10 mV and an output current of 194 nA. The single Sb-doped ZnO microbelt shows a Seebeck coefficient of about -350 μV/K and a high power factor of about 3.2 × 10(-4) W/mK(2). The fabricated NG demonstrated its potential to work as a self-powered temperature sensor with a reset time of about 9 s.

Bacterial Stripe of Hog Millet Caused by Acidovorax avenae subsp. avenae, a New Disease in Korea

In July 2011, bacterial stripe was observed on a commercial field of hog millet (Panicum miliaceum L.) in Chuncheon, Korea, with a disease incidence of 37% in the field. Symptoms on leaves included reddish-brown, long, narrow stripes that varied in length and were sharply delineated by uninfected adjacent vascular bundles. Eleven bacterial isolates (BC3107, BC3214 to BC3223) were recovered on trypticase soy agar from lesions surface sterilized in 70% ethanol for 1 min. The isolates, all obtained from different plants, were gram negative, oxidase positive, aerobic rods with two to four flagella. The isolates produced circular, cream-colored, nonfluorescent, butyrous colonies with entire margins on King's B medium. Using the Biolog Microbial Identification System, Version 4.2 (Biolog Inc., Hayward, CA), the isolates were identified as Acidovorax avenae subsp. avenae with Biolog similarity indices ranging from 0.52 to 0.72 after 24 hr. Characters for differentiating between Acidovorax spp. were tested according to Schaad et al. (2). The isolates were positive for gelatin liquefaction, nitrate reduction, lipase production, utilization of D-mannitol, sodium citrate, and alkaline in litmus milk. The isolates were negative for utilization of D-arabitol and did not amplify with PCR primer sets Aaaf5, Aaaf3/Aaar2, and Aacf2/Aacr2. Colonies were V^-, V⁺, and V⁺ for utilization of D-fucose, maltose, and ethanol, respectively. Regions of the 16S rRNA (rrs) and the IGS were sequenced to aid in the identification of the isolates using reported PCR primer sets (1,4). A 1,426 bp fragment of the rrs region shared 100% similarity with all strains of A. avenae available in GenBank. Pathogenicity tests were separately performed for the 11 isolates in different greenhouses located in Suwon (National Academy of Agricultural Science), and Chuncheon (Gangwondo Agricultural Research and Extension Services) in Korea. Pathogenicity was confirmed by clip inoculation with sterilized scissors dipped into cell suspensions containing 10⁵ CFU/ml on three 8-day-old leaves of hog millet (two plants per isolate), rice (Oryza sativa L. cv. Hopyeong), and sweet corn (Zea mays L. cv. Daehak) in a greenhouse maintained at 28 to 32°C and 90% relative humidity. The isolates induced similar symptoms as those originally observed on hog millet 5 days after inoculation. No symptoms were observed on the control plants (hog millet, rice, and sweet corn), which were clipped with scissors dipped in sterilized distilled water. The identity of bacteria reisolated from the stripes on inoculated leaves was confirmed by analyzing sequences of the 16S-23S rRNA intergenic spacer region (IGS) (1). On the basis of physiological, pathological, and sequence data, the isolates were identified as A. avenae subsp. avenae. To our knowledge, this is the first report of bacterial stripe of hog millet caused by A. avenae subsp. avenae in Korea. The spread of the bacterial disease is expected to have a significant economic impact on hog millet culture in the fields of Gangwon Province in Korea. Nucleotide sequence data reported are available under accession numbers JQ743877 to JQ743887 for rrs of BC 3207 and BC3214 to BC3223, and JQ743877 to JQ743887 for IGS of BC3207 and BC3214 to BC3223. References: (1) T. Barry et al. The PCR Methods Appl. 1:51, 1991. (2) N. W. Schaad et al. Syst, Appl. Microbiol. 31: 434, 2008. (3) K. Tamura et al. Mol. Biol. Evol. 28:2731, 2011. (4) W. G. Weisburg et al. J. Bacteriol. 173: 697, 1991.

Bacterial Leaf Spot of Zinnia Caused by Xanthomonas campestris pv. zinniae, a New Disease in Korea

In September 2011, bacterial leaf spot was observed on zinnia plants (Zinnia elegans L.) grown in a garden in Suwon, Korea. Leaf symptoms included angular lesions that were yellow or brown-to-reddish brown in the center. Bacterial isolates (BC3293 to BC3299) were recovered on trypticase soy agar from lesions surface-sterilized in 70% ethyl alcohol for 1 min. Pathogenicity of the isolates was confirmed by spray inoculation with a bacterial suspension (10⁶ CFU/ml) prepared in sterile distilled water and applied to zinnia plants at the four- to five-leaf growth stage (two plants per isolate). Sterile distilled water was used as the negative control. The inoculated plants were incubated in a greenhouse at 26 to 30°C and 95% relative humidity. Characteristic leaf spot symptoms developed on inoculated zinnia plants 5 days after inoculation. No symptoms were observed on the negative control plants. The bacterium reisolated from the inoculated leaves was confirmed through gyrB gene sequence analysis (3). All isolates were gram-negative, aerobic rods, each with a single flagellum. Isolates were positive for catalase and negative for oxidase. The biochemical and physiological tests for differentiation of Xanthomonas were performed using methods described by Shaad et al. (2). The isolates were positive for mucoid growth on yeast extract-dextrose-calcium carbonate agar, growth at 35°C, hydrolysis of starch and esculin, protein digestion, acid production from arabitol, and utilization of glycerol and melibiose. Colonies were negative for ice nucleation, and alkaline in litmus milk. The gyrB gene (870 bp) and the 16S-23S rRNA internal transcribed spacer (ITS) regions (884 bp) were sequenced to aid in identification of the original field isolates using published PCR primer sets Xgyr1BF/Xgyr1BR (3) and A1/B1 (1), respectively. Sequence of the gyrB gene (GenBank Accession Nos. JQ665732 to JQ665738) from the zinnia field isolates shared 100% sequence identity with the reference strain of Xanthomonas campestris pv. zinniae (GenBank Accession No. EU285210), and the ITS sequences (GenBank Accession Nos. JQ665725 to JQ665731) had 99.9% sequence identity with X. campestris pv. zinnia XCZ-1 (GenBank Accession No. EF514223). On the basis of the pathogenicity assays, biochemical and physiological tests, and sequence analyses, the isolates were identified as X. campestris pv. zinniae. To our knowledge, this is the first report of bacterial leaf spot of zinnia caused by X. campestris pv. zinniae in Korea. The disease is expected to result in economic and aesthetic losses to plants in Korean landscapes. Thus, seed treatment with bactericides will be required to control the bacterial leaf spot of zinnia before planting. References: (1) T. Barry et al. The PCR Methods Appl. 1:51, 1991. (2) N. W. Schaad et al. Page 189 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. N. W. Schaad et al., eds. The American Phytopathological Society, St. Paul, MN, 2001. (3) J. M. Young et al. Syst. Appl. Microbiol. 31:366, 2008.

Lead-free nanogenerator made from single ZnSnO3 microbelt

We demonstrated a single-microbelt nanogenerator first made using a ZnSnO(3) microbelt that generated an output power of ∼3 nW under a compressive and releasing strain of 0.8-1%. The ZnSnO(3) nanobelts/microbelts were synthesized using a vapor transfer process at 1173 K. The X-ray diffraction pattern shows that the microbelts belong to ZnSnO(3) with rhombohedral structure. An individual ZnSnO(3) microbelt was bonded at its ends on a flexible polystyrene substrate as a nanogenerator, which gives an output voltage and current of 100 mV and 30 nA, respectively, corresponding to an energy conversion efficiency of 4.2-6.6% (based on 0.8-1% strain). Our results show that ZnSnO(3) microbelts are one of the highly promising materials for lead-free piezoelectric energy harvesting.

Ultrahigh sensitive piezotronic strain sensors based on a ZnSnO3 nanowire/microwire

We demonstrated a flexible strain sensor based on ZnSnO(3) nanowires/microwires for the first time. High-resolution transmission electron microscopy indicates that the ZnSnO(3) belongs to a rhombohedral structure with an R3c space group and is grown along the [001] axis. On the basis of our experimental observation and theoretical calculation, the characteristic I-V curves of ZnSnO(3) revealed that our strain sensors had ultrahigh sensitivity, which is attributed to the piezopotential-modulated change in Schottky barrier height (SBH), that is, the piezotronic effect. The on/off ratio of our device is ∼587, and a gauge factor of 3740 has been demonstrated, which is 19 times higher than that of Si and three times higher than those of carbon nanotubes and ZnO nanowires.

Tin-doped rutile titanium dioxide nanowires: luminescence, gas sensor, and field emission properties

Sn-doped rutile TiO2 nanowires were synthesized by a thermal reactive evaporation route. Field emission scanning electron microscopy (FESEM) imaging reveals that the Sn-doped TiO2 nanowires exhibited diameters of 80-150 nm and 2-3 microns in length. High-resolution transmission electron microscopy (HRTEM) imaging makes it possible to observe that Sn-doped TiO2 nanowires show a certain lattices fringe of approximately 0.32 nm, which demonstrates that the nanowires are single crystalline with rutile structure and grow along the [110] axis. Cathodoluminescence (CL) reflected that on the surface of Sn-doped TiO2 nanowires, many oxygen vacancies and defect states were formed during the crystal growth. These defect states raised a broad emission peak around the red-orange band. The ethanol sensing properties of Sn-doped rutile TiO2 nanowires at a temperature of 190 degrees C for the ethanol concentrations of 50, 100, 150, 200, 400, 500, and 600 ppm, correspond to the sensor' sensitivity of 7, 12, 18, 19, 23, and 26%, respectively. The sensitivity increased with an increase in the ethanol concentration. As-synthesized TiO2 nanowires revealed a turn-on field, approximately 5.1 V/microm, at a current density of 1 microAcm(-2).

Effects of Os inserted layers on the microstructures and magnetic properties of the FePt films

The microstructure and magnetic properties of multilayer [Os(t)/FePt(x)]n films on a glass substrate with a 10 nm Os buffer layer by ion beam sputtering have been studied as a function of the annealing temperatures between 300 and 800 degrees C. Here, t = 0.2, 1 or 5 nm and x varied from 10, 20, 25, 50, to 100 nm with its associated n value of 10, 5, 4, 2, and 1, respectively. No diffusion evidence was found in samples with a thin Os layer and t > or = 1 nm. The average grain size of the multilayer films can be well controlled by both annealing temperature and thickness of the FePt layer by a very thin Os space layer with t > or = 1 nm. The enhancement of H(c) can be understood from the fact that for a FePt film with an Os spacer layers, the increasing number of Os layer will inhibit the grain growth of FePt grains and enriches the grain boundary. We have experimentally demonstrated that even with a very thin 1 nm Os spacer layers, the [Os(t)/FePt(x)]n multilayer films can exhibit good hard magnetic properties and are attractive candidates for ultrahigh density magnetic recording media.