Hom-tensor关系式中的两个逆同构

模范畴中有两个重要的Hom—tensor关系式,通常是利用一般的范畴和函子理论来证明的,这种证法没有给出其中的自然同构的逆同构。本文利用投射模的对偶基,给出了它们的逆同构。     

正交各向异性矩形层合悬臂板振动问题的近似解及实测

本文利用能量法(瑞利法)近似计算悬臂支承正交各向异性层合板振动的固有频率,并对碳/环氧[90/0](?)正交层合板进行实测。##原图像不清晰     

4种天然气基汽车燃料的生命周期3E评价

以天然气基汽车代用燃料系统为研究对象,运用生命周期评价方法,评估用天然气生产压缩天然气、甲醇、二甲醚、柴油四种代用燃料系统的生命周期指标,从能源、环境和经济(3E)三方面评价天然气基汽车代用燃料系统;为推广能耗少,对生态环境友好,经济上可接受的能源及能源政策的制定提供依据.     

The Mechanism of Negative-ion Generation of Natural Fiber Fabrics

Generally there are three kinds of substances used as negative-ion generator in textiles, natural silicate minerals （ceramic/tourmaline）, natural rare-earth minerals and natural sediment with ultra-fine pores. Based on different additive, the mechanism of negative-ion generation is largely divided into three kinds, the piezoelectricity and pyroelectricity of tourmaline crystal, air ionization caused by low-level radiation and breaking up of the clusters of moisture in air when going through the ultra-free pores of natural sediment. In this paper, the negative-ion generating properties of natural fiber fabrics-cctton, wool, silk and linen were first proposed. By some kind of physical stimulation, rubbing or vibrating, natural fiber fabrics without any additive could also emit negative ions. Considering that the piezoelectric effect was observed in wool fibers, silk fibers and cellulose fibers, the piezoelectricity was studied as a mechanism of negative-ion generation of natural fiber fabrics. Another possible mechanism was the tribeelectricity produced by the sense of ntbbtng or vibrating and tip discharge of hairiness. The Final experiment results verified that the latter would be the main reason, and the electrolytic dissociation of moisture was also contributing to negative-ion generation.     

天然气转换后热水器使用过程中毒事故分析

烟台市人工煤气转换成天然气后,曾发生过用户在使用改造后的热水器洗澡时的中毒事故。本文就燃气具在天然气转换中的适应性分析了事故的原因,并提出合理化建议。     

磁电式速度传感器动态特性分析

本文介绍了磁电式绝对速度传感器频率响应函数的实验确定方法和实验系统。根据试验数据，分析了传感器的动态特性，此外，给出了传感器可使用的频率范围。     

用SAP5程序分析纺纱锭子的振动

随着计算机技术的发展和各种新型测试手段的出现,工程设计进入了一个新的阶段,即由早先的静态设计进入到动态设计,进一步采用了计算机辅助设计.本文应用大型通用结构程序SAP5计算了国产D3203精纺锭子的临界速度及振型,分析了锭子结构各种因素对其临界速度及振型的影响,初步选择了适当的锭子参数,以保证锭子的临界速度远离工作速度,提高锭子的运动稳定性,降低噪声,节约功耗.文章还给出了各刚度的参考值,为锭子的改进设计提供了方向.     

Cytotoxicity of human peripheral blood T-lymphocyte clones activated by hepatitis B virus surface antigen

Summary The present studies examined the cytotoxic activities of peripheral blood lymphocytes (PBL) from volunteers with (sero-positive) and without (sero-negative) circulating antibodies to hepatitis B virus surface antigen before and 30 days after vaccination with hepatitis B virus surface antigen (HBsAg). Long-term culture of monospecific hepatitis B surface (HBsAg)-responsive T-lymphocytes were isolated and grown in large numbers. The mechanism of T-cell mediated cytolysis, and the identification of the carbohydrate determinants on the surface of these effector cells responsible for the killing effect, are being examined.     

中国保险公司风险收益水平实证分析

社会各界非常关注保险公司经营的安全性与收益性.文章通过对资产收益率的讨论,实证分析中国保险公司的风险收益水平,认为中国保险市场初步呈现了"寡头垄断"市场的特点,并提出了相关建议.