The influence of the fabrication process on the buckling of thin-walled steel box sections

Steel box sections are usually fabricated from flat plates which are welded at the corners. The welding process can introduce residual stresses and geometric imperfections into the sections which can influence their strength. For some thin-walled sections, large periodic geometric imperfections have been observed in manufactured sections. Subsequent investigations have indicated that the imperfections are in fact buckling deformations i.e. the box section has buckled due to welding residual stresses prior to any application of external load. The welding procedure and the behaviour of the box sections under load has been modelled using a finite element analysis that accounts for both geometric and material non-linearities. Tests have been carried out on box sections with a range of width to thickness ratios for the plate elements. Modelling has been shown to give good correlation with the test results. The conditions for buckling to take place as a result of the welding process have been established. A design method has been proposed.     

Trypsin Inhibitor Activity In Vitro Digestibility and Sensory Quality of Meat-Like Yuba Products as Affected by Processing

ABSTRACT: :
Soybeans ( Glycine max ) were soaked and ground to obtain soymilk. The soymilk was cooked in an open tank and held at 85 to 90 deg;C. Yuba films were picked up in 20 min intervals and dried for 20 min. Yuba films were soaked in chicken-flavor solutions (25% and 35%), and baking soda (BS) solutions (0%, 1%, 2%, and 3% BS), and cooked at 100 °C for 30 min, 60 min, and 90 min. TIA decreased (p < 0.05) with the increase of heating time and BS concentration. In vitro protein digestibility (IVPD) decreased with heating time and BS concentration (p < 0.05). Sensory characteristics were affected by flavor concentration. By using 0% BS, 25% of the chicken flavor concentration, and a short heating time method, meat-like products with low TIA, high IVPD, and good sensory characteristics were obtained.     

应用德国PAR88挤出机生产PVC异型材的工艺研究

从控制PVC异型材挤出机的工艺参数的角度，分析并论述了挤出机工艺参数对PVC异型材低温落锤性能的影响。     

用快切装置替代备自投装置提高厂用电安全可靠性

指出目前厂用电切换装置存在的不足，分析了快切装置的基本原理以及厂用电事故下的成功快切对电厂安全生产的意义，说明了在厂用电切换中尽快应用快切装置的必要性。     

8Li次级束的产生

在北京串列加速器次级束流线上通过2 H(7Li,8Li) 1H逆运动学反应产生了用于核天体物理研究的8Li次级束。准直后的次级束纯度达到 80 %以上 ,对于 44MeV的7Li强度约为 3 0s- 1·pnA- 1,可以用来进行逆几何转移反应的实验测量。     

大功率UPS的并联控制技术

提出了一种新的N 1三相大功率UPS的并联控制方案，并且在4台40KVA三相在线式UPS上进行了实验研究，实际运行结果证明采用此方法可以获得良好的静态与动态特性。     

环形截面大偏心受压构件截面延性系数计算

延性是混凝土构件的一项重要特性 ,延性系数是构件延性的度量 ,由于沿周边均匀配筋环形截面偏心受压构件受力计算的特殊性 ,至今没有一个较精确的计算公式。本文根据沿周边均匀配筋环形截面偏心受压构件的工作特点 ,采用常用应力应变关系和基本假设 ,提出了其延性系数的计算方法。     

复合乳化沥青的粘附性试验方法研究

鉴于目前使用的阳离子乳化沥青粘附性试验方法难以有效评价复合乳化沥青粘附性，通过试验研究并综合考虑乳化沥青施工和路用实际情况，提出了乳化沥青水煮法试验方法和采用该方法检验复合乳化沥青粘附性时的评定标准。     

联产供冷与电力供冷能耗比较分析

文中将两种供冷能耗比较分解成用电煤耗差、用热煤耗量、增加产汽用电煤耗量三部分进行分析，按照热量法得出在目前一般情况下联产供冷比电力供冷通常费能和定性定量结论，为全面研究比较热电冷联产与分产的能耗奠定一个基础。     

葡萄栽培品种花芽高节位分化观察研究

在管理良好、植株健壮的条件下，葡萄花芽高节位分化是一个普遍的现象。一年生枝从低节位到高节位均可形成正常的花芽，并能正常开花结果，而且高节位分化花芽对当年的果实品质及次年的花芽分化无不良的影响。合理利用这一特性对促进葡萄幼树早丰产有重要的指导意义。