Formation of a nanocrystalline surface layer on steels by air blast shot peening

A nanostructured surface layer was fabricated on two kinds of steels by means of air blast shot peening. The nanolayer shows a sharp boundary to the underlying work-hardened area and good thermal stability up to 873 K. It has much higher hardness than the work hardened region in both the as-treated and annealed states. When using small shot sizes, the nano area can be formed in very short treatment times, and the thickness and continuity of the nanolayer is enhanced. On the contrary, the nanocrystalline region is more difficult to synthesize when using large shot particles, even though the deformed area is much thicker. The effect of particle diameter is attributed to the different collision time and different strain rate of the treated materials.     

Growth of Fe3O4 whiskers from solid solution nanoparticles of Fe–Cu and Fe–Ag systems produced by DC plasma jet method

Fe–Cu and Fe–Ag binary systems are virtually immiscible for a whole range of composition in equilibrium. In the present study, the nanoparticles of Fe–Cu and Fe–Ag systems were produced by direct current plasma jet method. These produced nanoparticles had mean particle sizes of about 70 nm, and were a mixture of bcc and fcc phases. It was revealed by analytical high-resolution TEM observations that the nanoparticles of Fe–Cu and Fe–Ag systems were supersaturated solid solution. It has been found that numerous whiskers with a particle on their tip grow from these nanoparticles by heating above the temperature of 860 K under an Ar–O₂ atmosphere. The whiskers grow as the result of the phase separation in these solid solutions. The whiskers are composed of a Fe₃O₄ rod and a Cu₂O particle on the tip.     

Gene transfer of human prostacyclin synthase prevents neointimal formation after carotid balloon injury in rats

BACKGROUND AND PURPOSE: A disordered proliferative process in the vascular wall is thought to underlie the pathogenesis of restenosis after percutaneous transluminal angioplasty and carotid endarterectomy. A growth inhibitory property of overexpressed prostacyclin (PGI2) synthase (PGIS) was recently implicated in the pathological proliferation of vascular smooth muscle cells (VSMC) in vitro. Here, we investigated the effects of increased PGI2 synthesis on the pathological proliferation of VSMCs. METHODS: The cDNA encoding human PGIS was transfected into endothelium-denuded rat carotid arteries after arterial balloon injury with the use of hemagglutinating virus Japan (HVJ). HVJ liposome vector complex without PGIS cDNA was used for vehicle control. The level of 6-keto PGF1alpha, a stable hydrolyzed metabolite of PGI2, the histological distribution of the immunoreactivity for human PGIS and the ratio of neointimal/medial area were analyzed. RESULTS: In the analyses of 6-keto PGF1alpha, the level in the carotid arteries was significantly elevated 3 days after PGIS expression-vector transfection compared with that in the arteries after vehicle transfection. Seven days after human PGIS expression-vector transfection, the PGIS cDNA-transfected neointimal cells were strongly positive for human PGIS immunoreactivity in 81% sections examined. Fourteen days after the injury, the ratio of neointimal/medial area was 1.2+/-0.4 in the PGIS expression-vector transfected group, which was significantly smaller than that of the vehicle control group, 1.7+/-0.5; P<0.01. CONCLUSIONS: It was thus demonstrated that the gene transfer of human PGIS expression-vector into rat carotid arteries resulted in the increased production of human PGI2 in the vascular wall, the expression of human PGIS in the developing neointima and significantly inhibited the neointimal formation generated after balloon injury.     

Presumptive technique of power generation of amorphous silicon cell including various factors

This paper describes the presumptive technique of power generation of amorphous silicon module considering various factors. The influences exerted by solar spectrum, spectral response, angle of incidence and efficiency deviation are evaluated. Then, various factors are formulated. The presumptive technique of power generation including these factors is examined. As a result, the proposal technique is able to presume with a high accuracy as compared with the conventional technique.     

Measurement of the magnetic characteristics of oriented silicon steel in an arbitrary direction

The measurement method and the experimental results on the magnetic characteristics of oriented silicon steel in any direction are described in this paper. A single sheet tester of rotational loss has been used in order to simulate conditions existing in real devices. The flux of any direction is induced in the specimen by exciting from X and Y directions in the same phase. The flux density was measured by each search coil. The magnetizing force was measured by the double H-coil method. The outputs of the B-coils and the H-coils were treated by sending the outputs from the wave digitizer to the personal computer. The components of the magnetic characteristics in the X and Y directions for small values of B are the same. Only the saturation value changes, and it depends on the direction of flux.     

Insulin-stimulated GLUT4 translocation is relevant to the phosphorylation of IRS-1 and the activity of PI3-kinase

We examined the role of 185-kDa insulin receptor substrate-1 (IRS-1) and phosphatidylinositol 3-kinase (PI3-kinase) in the signaling pathway of insulin-stimulated GLUT4 translocation. We had already developed a novel cell line to detect GLUT4 on the cell surface, directly and sensitively (Kanai, F., Nishioka, Y., Hayashi, H., Kamohara, S., Todaka, M., and Ebina, Y. (1993) J. Biol. Chem. 268, 14523-14526). We stably expressed a mutant insulin receptor in which Tyr972 was replaced with phenylalanine. Insulin-stimulated tyrosyl phosphorylation of IRS-1 and GLUT4 translocation were decreased in cells expressing the mutant receptor, as compared to findings in cells expressing the normal receptor. Wortmannin, an inhibitor of PI3-kinase, inhibits the insulin-stimulated PI3-kinase activity and GLUT4 translocation at 50 nM, but not the NaF-stimulated GLUT4 translocation. These results suggest that the tyrosine phosphorylation of IRS-1 and activation of PI3-kinase may be involved in the signaling pathway of the insulin-stimulated GLUT4 translocation.     

A calculation of torque in motors considering rotor eccentricity

A new analytical approach to the finite element calculation of torque in motors including eccentric rotor, based on the Maxwell stress method, is proposed in this paper, where the effects due to eccentricity on the cogging torque and the torque characteristics with regard to the speed are confirmed. A brushless dc motor is employed as an analytical model for two kinds of eccentricity. Consequently, in the case of eccentric motors, the unbalanced radial force functions as the repulsive force against rotation which causes the reduction of average torque, and two kinds of eccentric motors have the same tendency regarding the effects on the torque. This proposed approach is applicable to any kind of motor including eccentric rotor. © 2000 Scripta Technica, Electr Eng Jpn, 132(4): 53–61, 2000     

A study of the loss characteristics of the amorphous magnetic material under nonsinusoidal wave magnetic flux

This paper presents a study on iron loss characteristics of an amorphous magnetic material under nonsinusoidal wave magnetic flux. The iron loss characteristics of the amorphous magnetic material have been compared to those of grain‐oriented magnetic steel sheets. Measurements of the iron loss have been carried out by means of an SST. It was found that the ratio of the iron loss increase of the amorphous magnetic material under the excitation by distorted waveforms and symmetric PWM waveforms is lower than that of grain‐oriented magnetic steel sheets. On the other hand, the ratio of the iron loss increase of the amorphous magnetic material under the excitation by asymmetric PWM waveforms is higher than that of grain‐oriented magnetic steel sheets. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(3): 11–18, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20004