Effect of aging treatment on irradiation-induced segregation of high Mn-Cr steel

To investigate the effect of aging treatment on irradiation-induced segregation of high Mn-Cr steel, specimens for electron-beam irradiation were prepared from the high Mn-Cr austenitic steel which was solution treated at 1 373 K for 1 h and aging treated at 573 K for 1 000 h, respectively. The electron-beam irradiation was performed at 573 K up to doses of 5.4 dpa in a 1 250 kV HVEM and irradiation-induced segregation analyses were carried out by an EDX in a 200 kV FE-TEM. The results show that void formation is not observed in both solution treated and aging treated ones. The amount of Cr segregation at the grain boundary decreases in the aged one; however, that of Mn is not changed in solution treated one.     

毛泡桐(原变种)内桐皮的化学成分

对玄参科(Scrophulariaceae)泡桐属(Paulownia)植物毛泡桐(原变种)(Paulownia tomentosa(Thunb.)Steud.var.tomentosa)内桐皮的化学成分进行了研究。采用Sephadex LH-20柱色谱及薄层色谱等方法进行反复纯化分离及制备,从其70%丙酮提取物乙酸乙酯萃取相中分离到5种化合物,经理化性质和波谱解析化合物分别鉴定为:对香豆酸(ρ-coumaric acid,Ⅰ)、咖啡酸(caffeic acid,Ⅱ)、毛蕊花糖苷(verbascoside,Ⅲ)、异毛蕊花糖苷(isoverbascoside,Ⅳ)和肉苁蓉甙F(cistanoside F,Ⅴ)。化合物Ⅰ和Ⅱ为酚酸类化合物,Ⅲ～Ⅴ为差向立构苯丙素苷类化合物,Ⅰ、Ⅱ和Ⅴ首次从该植物中分离得到。     

Numerical investigation on welding residual stresses in a PWR pressurizer safety/relief nozzle

This paper presents finite element simulation results of residual stresses in dissimilar metal welds of a PWR pressurizer safety/relief nozzle. The present results are believed to be significant in two aspects. The first one is to consider the effect of the presence of similar metal welds on resulting residual stresses. The second one is the mitigation effect of the overlay welding thickness on residual stresses. After dissimilar metal welding, tensile residual stresses are present both at the inner surface and at the outer surface of dissimilar metal welds. Adjacent similar metal welding, however, decreases residual stresses to compressive ones at the inner surface of dissimilar metal welds, possibly due to the bending mechanism caused radial contraction of the weld. At the outer surface of dissimilar metal welds, similar metal welding increases residual stresses. Overlay welding further decreases residual stresses at the inner surface of dissimilar and similar metal welds, but increases slightly residual stresses at the outer surface.     

基于内存的时空索引TPR*树并发控制方案

随着定位技术的发展，基于定位的服务对数据库技术的要求越来越高，需要用它记录和管理大量持续运动物体的位置。TPR*树是支持移动物体现在和将来位置查询的索引结构，面临多个事务同时访问数据的问题。该文提出了基于内存的TPR*树的并发控制方案，能满足事务的一致性要求。通过结合加锁技术和时间戳技术，使得冲突减少，提高了并发效率和处理速度。     

SHELF-LIFE DETERMINATION OF PRECOOKED FROZEN PORK MEAT PATTIES AT VARIOUS TEMPERATURES

Precooked frozen pork patties sampled from the same lot were stored at −10, −15 and −20C after vacuum packing in PE bags for the determination of shelf -life. The patties were sampled 10–13 times at 3–4 week intervals and were subjected to the determination of volatile basic nitrogen (VBN), peroxide value (POV), thiobarbituric acid reactive substances (TBA), surface color and texture after thawing at 5C for 15 h. Results from the triangle test were used to determine high quality life (HQL), and the scoring test and the quality index were used to determine practical quality life (PQL). The test results showed that VBN, TBA and POV in the samples increased as the storage period was extended. It was noted that color of samples became darker during the storage as indicated by the decrease in L value from 63.7 to 59.2. In addition, the shear force of the stored samples increased from 3.2 to 5.5 psi during the storage period. HQL of the meat patties were 147, 168 and 196 days, and the PQL 189, 224 and 252 days at −10, −15 and −20C, respectively. Statistical analysis of test results indicated that there were significant relationships between sensory scores and VBN, TBARS and POV of the stored patties (P<0.05). VBN was selected as the most reliable objective quality index for the shelf-life determination (PQL) of the precooked frozen meat patties, and PQL estimates based on VBN were close to those determined based on the sensory tests.     

对具有不确定性的移动对象数据库的模型改进*

针对带不确定性移动对象的模型在回答未来时空查询时的提问及查询计算量方面所存在的问题,提出了改进方案。该方案使移动对象数据库和用户对于信息不精确的容忍度之间得到了很好的协调。     

Transverse Flux Induction Coil for Uniform Bar Heating Excluding Edge

This work particularly focuses on compensating Joule heat in under-heated areas occurred when thin steel bar is(<20 mm)heated by transverse flux induction heater(TFIH).The under-heated areas take place in range of 50~150mm from the both edges,so Transverse Flux Induction Coil(TFIC)including a magnetic core is proposed and optimized to supplement this fault.The solutions on the electromagnetic field are obtained numerically by commercial code MAXWELL 3D software from ANSYS Corp.and then,verified experimentally by pilot-scale tests,in which the TFIH was manufactured with a nominal power of 100 kW at a fundamental frequency of 1 kHz.Ultimately,TFIC having geometrically the optimized magnetic core made the heating pattern U-shaped,so could supply a desirable temperature profile for the rolling process.