Interfacial structures and mechanical properties of steel–Ni and steel–Ti diffusion bonds

Static and fatigue shear tests of steel–Ni bonds and steel–Ti bonds were carried out to obtain the relations between the strengths and the bonding conditions. Ultrasonic measurements were also made to examine the relations between the strengths and the size of the bonded region (the estimated diameter). At the bonding interface of the steel–Ni bonds, no intermediate phase was observed. At the bonding interface of the steel–Ti bonds, a thin layer of intermetallic compound was formed at lower bonding temperatures but, at higher bonding temperatures, the interlayer melted and the bonding interface became rough. The intensity of the ultrasonic wave reflected from the bonding interface changed, depending on the state of the bonding interface. In shear tests of the steel–Ni and steel–Ti bonds, cracks propagated along the bonding interface, and the strength was proportional to the square of the estimated diameter. In fatigue tests, cracks propagated in the thickness direction of the plate and no relation was obtained between the fatigue life and the estimated diameter. Fatigue life distributions were represented by two- and three-parameter Weibull distributions. This revised version was published online in November 2006 with corrections to the Cover Date.     

Detection of Chemiluminescence Produced during Beer Oxidation

Chemiluminescence (CL) produced in beer was detected using the single photoelectron counting system. CL production did not occur in a nitrogen atmosphere but did occur in air and was dependent on incubation temperatures. It was inhibited by the addition of ascorbic acid. CL analysis should provide useful information in the study of oxidative deterioration of beer.     

High Temperature Storage Effect on Longevity of Rice Seeds

Storage of Indica (Oryza sativa L. cv. Katakutara) and Japonica (Oryza sativa L. cv. Kusabue) rice seeds at 30° and 40°C for 2 months in the dark did not result in the loss of viability in both cultivars. Storage at 60°C, however, resulted in a complete loss of germination after 45 days in the case of Kusabue while the Katakutara rice seeds retained the germination potential well above 95%. Corresponding increases in the linoleic acid content of the free fatty acid fraction and TBA values of the extracted lipid fraction were also observed in Kusabue rice seeds. The investigation indicated that the Indica rice seeds were better protected than the Japonica rice seeds by the enclosing rice hull during the storage period.     

哺乳动物细胞中糖链结构的改造

由于蛋白质需要正确的折叠和糖基化修饰,目前生物药用蛋白质主要通过哺乳动物细胞生产。然而利用哺乳动物细胞生产医药蛋白质也面临着高成本、糖链不均一等问题。本研究中,我们构建了敲除高尔基体α-1,2-甘露糖苷酶Ⅰ的HEK293细胞株,其中MAN1A1和MAN1A2双敲除细胞株D-KO35中蛋白质上高甘露糖型N-比例增加。在这株双敲细胞中,溶酶体膜蛋白LAMP2上的糖链对糖链内切酶-H处理敏感,证明蛋白上N-糖链结构以高甘露糖型结构为主。研究结果表明,在哺乳动物细胞中敲除高尔基体α-1,2-甘露糖苷酶的细胞株,可用于生产均一化N-糖链结构的重组糖蛋白。     

Detection of Free Radicals in Beer Oxidation

Short-lived radicals produced during the incubation of beer at 60°C were detected by electron spin resonance (ESR) spectroscopic analysis using N-tert-butyl-α-phenylnitrone (PBN) as a spin trapping reagent. The hyperfine splitting (hfs) constants were 15.7 ± 0.2 G and 3.2 ± 0.2 G for α_N and a^β_H, respectively. The hfs constants of PBN adducts produced by Co⁶⁰γ irradiation were 15.6 ± 0.3 G and 3.1 ± 0.2 G for α_N and α^β_H in beer and 15.7 ± 0.3 G and 3.3 ± 0.3 G for α_N and α^β_H in double distilled water. It is proposed, therefore, that short-lived radicals produced during the incubation of beer at 60°C may be hydroxyl radicals.     

Improvement of Sensitivity of a Compact Magnetometer by Using HTS‐SQUID with Rotating Sample

We have improved a previously developed compact magnetometer using HTS‐SQUID with a rotating sample. In the previous system, attenuation of the rotational speed had resulted in deformation of the averaged waveform signal, reducing the reproducibility of measurements. In this paper, we have used a better motor in order to decrease the attenuation of the rotational speed for precise averaging of the output signal and improvement of the signal‐to‐noise ratio. To improve sensitivity, we also optimized the pickup coil and compared the signal‐to‐noise ratio of circular and elliptical pickup coils having the same number of turns, resistance, and inductance. As a result, the signal‐to‐noise ratio was improved with high accuracy and the magnetometer showed a susceptibility sensitivity of 3.8× 10^?9 emu.     

无铅焊及焊接点的可靠性试验

随着电子装置的小型化的发展,欧盟(EU．)的WEEE和RoHS提出禁止使用Sn-Pb焊 锡。这将导致一系列的工业革新,如部件体积和重量的减少,各种各样无铅产品的出现,改变现有 的焊接生产线等。参照国际标准(IEC,ISO)和日本国家标准(JIS),并根据这些标准做了一系列的试 验,通过试验对无铅焊润湿性、强度、耐久性等可靠性的评价方法进行说明。     

Free radical reactions in beer during pasteurization

Oxidative reactions during beer pasterization were studied using chemiluminescence (CL) and electron spin resonance (ESR) analyses. the CL production of beer was acclerated by pasteurization and the maximum CL intensity appeared sooner than that in non-pasteurized beer. Beers pasteurized with 15–30 pasteurization units (P.U) had the same CL producing activities as the non-pasteurized beers stored at 20°C for 6–10 days. Free radicals were produced and some of them were consumed by beer oxidation during pasteurization. It seems that free radicals were consumed by beer oxidation during pasteurization. It seems that free radical reactions occur in beer during pasteurization and that the degree of oxidation during pasteurization generally corresponded to that of non-pasteurized beer stored at room temperature for about 1 wee.