GCr15钢轴承套圈的磨削开裂失效分析

通过金相分析及断口观察，对GCr15钢轴承套圈的磨削开裂进行了系统分析。结果表明．淬火裂纹是套圈失效的根本原因，而原材料中Cr的带状偏析、套圈表面的应力集中、淬火加热时的氧化脱碳以及不当的磨削工序则共同加剧了淬火裂纹的萌生和扩展。     

可聚合表面活性剂的应用研究

可聚合表面活性剂含有聚合活性基团,在无皂乳液聚合、纳米材料制备等新兴领域得到应用.主要综述了可聚合表面活性剂在溶液中可形成的微观有序组合体结构类型,分别论述了它们的应用性能,并对其研究趋势进行了展望.     

响应面优化褶皱假丝酵母脂肪酶催化合成木质甾醇油酸酯

以木质甾醇转化率为指标,考察了10种常见商业化脂肪酶催化合成木质甾醇油酸酯的效果,确定褶皱假丝酵母脂肪酶(CRL)为优选生物催化剂,进一步筛选出正己烷为优选反应介质.在脂肪酶用量、油酸和木质甾醇的物质的量比、反应温度和反应时间这4个单因素考察基础上,通过响应面分析法对酶催化木质甾醇油酸酯合成工艺条件进行优化,并对优化条件进行验证和放大实验.CRL催化合成木质甾醇油酸酯的优化工艺参数为:CRL添加量为木质甾醇质量的10％,油酸与木质甾醇的物质的量比为3.8:1,反应温度为46℃,反应时间为28 h,木质甾醇的转化率为91.56％±0.25％.     

单宁改性酚醛树脂的研制

介绍了用橡碗单宁制备改性酚醛树脂的合成工作，并以水为溶剂进行了改性酚醛树脂的粘接性能研究，讨论了固化温度，固化时间对粘接强度的影响。     

耐高温的多层包装薄膜及其制品

<正> 西德专利3339836介绍了一种多层耐高温包装膜及其制品的制造方法。该包装材料耐热,抗压,耐磨损性好。可在温度为70—120℃的容器内处理10分钟至15小时,因此最适宜用于食品包装,可作成食品包装袋等制品.这种多层包装材料外层所用的异分子聚胺,可用至少两种不同的聚酰胺单体进行异分子聚合制成,其熔点为120℃—240℃,     

Inhibitory effect of Cr（Ⅵ） on activities of soil enzymes

To evaluate the influence of various Cr(VI) concentrations (0.05, 0.25, 0.50, 1.00 and 2.00 g/kg) on the activity of soil enzymes, the activities of catalase, polyphenol oxidase, dehydrogenase, alkaline phosphatase in soils were investigated in the incubation experiment with a period of 35 d. The results indicate that all the tested Cr(VI) concentrations significantly inhibit dehydrogenase activity by over 70% after 35 d. The activity of alkaline phosphatase is slightly inhibited during the whole experiment except for on the day 7. Cr(VI) has no obvious effect on the activity of catalase in soil. On the contrary, Cr(VI) stimulates the activity of polyphenol oxidase. The results suggest that dehydrogenase activity can be used as an indicator for assessing the severity of chromium pollution. Foundation item: Projects(2006AA06Z374, 2007AA021304) supported by the National High-Tech Research and Development Program of China; Project(2008SK2007) supported by the Key Program of Science and Technology of Hunan Province, China     

基于溶剂沥青的冷再生沥青混合料性能评价

传统的沥青混合料冷再生技术有乳化沥青和泡沫沥青冷再生,本研究尝试采用所开发的溶剂沥青作为结合料对废旧沥青混合料进行冷再生,提出了试件的成型和养生方法,进行了配合比组成设计并采用热拌沥青混合料的标准对溶剂沥青冷再生混合料的性能进行评价.试验结果表明,溶剂沥青冷再生混合料的水稳定性能、高温稳定性能均满足我国热拌改性沥青混合料规范的性能要求,低温性能虽然不满足改性沥青混合料的要求,但能满足普通沥青混合料规范的性能要求.     

具周期边界的神经传播型方程的初边值问题解的存在唯一性

神经传播型方程的研究是非线性科学和神经科学交叉的前沿课题,既有实际应用背景,又有重要的理论意义.讨论了具周期边界的神经传播和非线性波动混合型方程的初边值问题,利用Galerkin方法及Sobolev空间理论证明了问题整体解的存在唯一性.     

浅议招标代理服务费收取的不合理性及处理建议

随着《中华人民共和国招标投标法》、《中华人民共和国招标投标法实施条例》颁布实施,招投标活动已成为当下一种平常的商品交易行为。而招标代理机构通过帮助不具有编制招标文件和组织评标能力的招标人选定合格的投标人,进而取得招标代理服务费已成为行业内的共识。但笔者在从事的招标代理活动中发现许多不合理之处:如在实际操作中出现招标人与招标代理机构签订招标代理合同,向     

Behavior,distribution and environmental influence of arsenic in a typical lead smelter

A field study was conducted to determine the behavior and distribution of arsenic during the pyrometallurgy process in a typical SKS(Shuikoushan) lead smelter in Hunan province, China. Environmental influences of arsenic in selected samples were evaluated. Arsenic contents in all input and output samples vary from 0.11% in raw lead to 6.66% in collected dust-2. More arsenic is volatilized in blast furnace and fuming furnace(73.02% of arsenic input) than bottom blowing furnace(10.29% of arsenic input).There are 78.97%, 13.69%, 7.31% of total arsenic distributed in intermediate materials, stockpiled materials and unorganized emissions, respectively. Matte slag-2, collected dust-1 and secondary zinc oxide are hazardous based on the arsenic concentrations of toxicity characteristic leaching procedure. According to risk assessment code(RAC) guideline, arsenic in collected dust-1 poses a very serious risk to the surrounding environment, arsenic in speiss, matte slag-2, water-quenched slag and secondary zinc oxide show low risk, while arsenic in matte slag-1, collected dust-2 and post dust has no risk to the environment.