Preparation and characterization of poly(ethylene/tetramethylene terephthalate) copolyesters

Random copolyesters were prepared from dimethyl terephthalate (DMT), ethylene glycol (EG) and butane 1,4-diol (BD) by melt-polycondensation techniques, using varying amounts of EG and BD. Compositions have been established by ¹H n.m.r. spectroscopy. Intrinsic viscosity and number average molecular weight ($\text{M}\text{?}{}_{\mathrm{n}}$) were measured. Thermal properties have been studied by differential thermal analysis. Melting and crystallization temperatures and thermodynamic parameters are discussed in terms of structural differences, particularly the effect of composition and chain flexibility. The degree of crystallinity from differential thermal analysis, i.r. and wide angle X-ray scattering (WAXS) are discussed.     

Quaternary Structure and Hetero-Oligomerization of Recombinant Human Small Heat Shock Protein HspB7 (cvHsp)

In this study, a reliable and simple method of untagged recombinant human HspB7 preparation was developed. Recombinant HspB7 is presented in two oligomeric forms with an apparent molecular weight of 36 kDa (probably dimers) and oligomers with an apparent molecular weight of more than 600 kDa. By using hydrophobic and size-exclusion chromatography, we succeeded in preparation of HspB7 dimers. Mild oxidation promoted the formation of large oligomers, whereas the modification of Cys 126 by iodoacetamide prevented it. The deletion of the first 13 residues or deletion of the polySer motif (residues 17–29) also prevented the formation of large oligomers of HspB7. Cys-mutants of HspB6 and HspB8 containing a single-Cys residue in the central part of the β7 strand in a position homologous to that of Cys137 in HspB1 can be crosslinked to the wild-type HspB7 through a disulfide bond. Immobilized on monoclonal antibodies, the wild-type HspB6 interacted with the wild-type HspB7. We suppose that formation of heterodimers of HspB7 with HspB6 and HspB8 may be important for the functional activity of these small heat shock proteins.     

运用韦柏函数分析发动机燃烧过程时若干问题的探讨

探讨了韦柏函数的内涵及其在实际应用中的若干问题；应用双韦柏函数对涡流室式柴油机的燃烧过程进行分析，加深了对分隔室式发动机燃烧过程的认识．     

汽轮机叶片用1Cr12Mo钢成分与热处理工艺对冲击韧度的影响

1Cr12Mo钢属于马氏体不锈钢,被广泛用于汽轮机亚临界机组的低压叶片。该钢在生产过程中由于冶炼方法的不同其化学成分会在一定范围内变化。对大量生产和试验数据进行分析的结果表明,成分的波动和热处理工艺参数的变化对钢的冲击韧度都有重要的影响。     

Cu(TO)2Cl2的制备和热力学研究（英）

根据制备过程,提出了配合物Cu(TO)2Cl2在混合溶液中的晶体生长的动力学模型。通过这个动力学模型,测定了一系列的动力学参数Ea=45.37kJ·mol-1,ln(A/s-1)=14.65,Δ≠Gm=82.11kJ·mol-1,Δ≠Hm=42.85kJ·mol-1,Δ≠Sm=131.58J·mol-1·K-1。另外,用RD496-Ⅲ型微量热计测定了该化合物在298.15K时的比热容,并计算了[Cu(TO)2]2 (aq)和Cu(TO)2Cl2(s)的标准生成焓。     

空调铜翅片冲压模工艺分析与设计

从企业生产实际出发，在进行冲压成形理论探讨和各种冲压工序变形特性分析的基础上，采用子模分立结构的设计思想，设计了一副适用于铜翅片冲压的专用模具。     

深井泵的研究现状与发展趋势

简要回顾了深井泵的发展历史.针对深井泵的研究情况,分别从其结构演变、水力设计方法、轴向力平衡方法等方面进行了较为详细的介绍.通过分析国内外深井泵的研究现状,指出了格兰富公司生产的冲压不锈钢井泵是具有广阔发展前途的产品,而采用专利技术"一种叶轮自身平衡轴向力的多级离心泵"生产的新型井泵代表了深井泵一个更新换代的优秀品种.同时指出利用数值模拟来进行平衡轴向力研究是一种有效的方法.     

大型纸机油站油温高的解决措施

北方大型纸机的油站热交换器因结垢、灰尘和菌泥沉积等原因造成热交换效率低,当油站油温高时可能引起纸机意外停机,成为影响纸机效率的主要因素之一。通过对油站冷却水系统的工艺优化（加过滤器和过滤网、使用抑垢剂、使用去离子水、使用杀菌防腐剂和定期清洗等措施）,基本解决了上述问题。     

Effect of a mixture of steam-flaked corn and soybeans on health, growth, and selected blood metabolism of Holstein calves

The objective of the experiment was to evaluate the effects of steam-flaked corn grains and soybeans on calf health, growth, and selected blood parameters. Holstein bull calves (n = 30, approximately 7 ± 3 d of age) were purchased from local dairy farms and offered milk, starter diets, and hay, and were then assigned to the experiment at 21 ± 3 d of age. Calves were blocked into 3 treatments by birth date and body weight and randomly assigned to receive fresh milk and a commercial pelleted starter containing extruded corn and soybeans (ECS), steam-flaked corn and soybeans (SFCS), or ground corn and soybeans (GCS). The experiment was conducted with calves from 3 to 13 wk of age. Body weight, calf starter intake, milk intake, total dry matter intake, and body structural growth were not significantly influenced by corn and soybean processing during the study; however, feed efficiency was significantly improved by the SFCS treatment. Average daily gain generally decreased during the weaning week for all treatments, but did not differ significantly among treatments. Health incidences for calves fed the SFCS starter were lower than those fed the other 2 treatments. The blood hematocrit was higher for calves fed the SFCS starter than for those fed the GCS and ECS starters during wk 6 to 11. The concentration of plasma β-hydroxybutyrate was higher for the calves fed the GCS and SFCS treatments than for those fed the ECS treatment during wk 6 to 13, but lower during wk 4 and 5. Plasma glucose concentrations decreased remarkably with increasing calf age but were not affected by corn and soybean processing. Plasma nonesterified fatty acids were influenced by calf age, and higher NEFA concentration was observed in the SFCS treatment than in the other 2 treatments during wk 5 to 9. Calves consuming the SFCS starter had similar average daily gain, milk intake, starter intake, total dry matter intake, and body structure, but had improved feed efficiency when compared with animals consuming the GCS and ECS starters. The SFCS starter decreased incidence of diarrhea during the postweaning period and required less veterinary treatment. These data suggest that the steam-flaking of corn and soybeans can influence the growth performance and the selected blood parameters of calves and that, in this study, the extrusion of corn and soybeans had no beneficial effect on the growth performance of calves.