Stick-Slip Motion of Machine Tool Slideway

Stick-slip motion of a moving element on an actual machine tool slideway is investigated experimentally under various sliding conditions, and the fundamental characteristics of the stick-slip motion are clarified. Based on these experimental results, the characteristics of static friction in the period of stick and kinetic friction in the period of slip are studied concretely so as to clarify the stick-slip process. It is shown experimentally that static and kinetic frictional coefficients can be expressed with simple formulas. Using these expressions, the boundary conditions for occurrence of stick-slip motion are examined, and the relation between properties of the stick-slip motion and frictional characteristics is explained quantitatively.

The viral DNA replication machinery of adenovirus 12

The viral DNA replication complex was found in the M band after fractionation. However, it did not associate with the nuclear membrane, but was found in association with types II and IV inclusions. It is suggested, therefore, that the viral DNA replication complex is the inclusions types II and IV. The analysis with Ad12 ts mutants showed the involvement of three viral genes in initiation of viral DNA replication, in formation of the viral DNA replication complex and the inclusions types II and IV. Temperature sensitivity of the gene products involved in viral DNA replication was also examined. From the data presented, the following sequence of viral DNA replication in Ad12-infected cells is suggested: (1) Synthesis of a protein (gene A product), which may be an acceptor or may modify the nuclear constituent to be an acceptor for parental viral DNA, to form the viral DNA replication complex; (2) synthesis of a protein (gene B product), which may be required for the parental viral DNA to associate with the acceptor and to form a type II inclusion-like structure (precursor of type II inclusion?); (3) synthesis of a protein (gene C product), which may be required for activation of the complex or type II inclusion and to alter type II inclusion to type IV inclusion. Further studies are necessary to substantiate the suggestion.

Stress Distribution at the Interface Between Tool and Chip in Machining

Stress distribution along a tool rake face were measured directly in the orthogonal machining of various metals. The method of measurement was based on the use of a composite tool which was divided into two parts parallel to a cutting edge in order to measure separately the force acting on one section of the tool. The stress distributions under actual cutting conditions were revealed, and the relationship between the nature of stress distribution and the mechanical properties of work material was clarified. It was ascertained that the nature of stress distribution was closely connected with the strain hardening index of work material and the frictional coefficient between tool and material.

Extravasation of angiographic contrast material in hypertensive intracerebral hemorrhage

✓ Leakage of contrast material during angiography is an uncommon phenomenon in hypertensive intracerebral hemorrhage. Intraparenchymal extravasation was demonstrated in five of 12 patients in whom serial cartoid angiography was carried out within 5 hours of hemorrhage. Extravasated material, first noted in the arterial phase, grew in size and density until the early venous phase and was still visible on the last 10-sec film. Three of the four in whom the hematoma was evacuated surgically showed clinical improvement.