Critical-point drying versus freeze drying for scanning electron microscopy: a quantitative and qualitative study on isolated hepatocytes

Critical-point drying and freeze drying were compared both quantitatively and qualitatively as preparative procedures for scanning electron microscopy. Isolated hepatocytes were used as model cells. Nomarski differential interference contrast microscopy was used for light microscopic measurements of the hepatocytes in the unfixed, the glutaraldehyde fixed, the glutaraldehyde + OsO₄ fixed, the critical-point dried and the freeze dried states. Critical-point dried hepatocytes were found to shrink to 38% of glutaraldehyde + OsO₄ fixed volume, whereas optimal freeze dried hepatocytes (frozen in water saturated with chloroform and freeze dried at 183 K for 84 h) were found to shrink to 51% of glutaraldehyde + OsO₄ fixed volume. Transmission and scanning electron micrographs of the critical-point dried cells showed well-preserved ultrastructure and surface structure. Micrographs of the freeze dried cells showed ultrastructure destroyed by internal ice crystals and surface structure destroyed by external ice crystals. Double-fixed isolated hepatocytes were shown to swell during storage in buffer and to shrink during storage after critical-point drying. For low magnification scanning electron microscopy (up to about 3000 times) both critical-point drying and freeze drying can be used. However, for high magnification scanning electron microscopy, critical-point drying is superior to freeze drying.     

地地战术导弹飞行可靠性指标评定方法

在小子样情况下 ,利用系统和分系统试验数据对导弹的飞行可靠性指标进行评定 ,从数学上说是系统可靠性综合问题 .运用MML SR方法对新型号地地战术导弹的飞行可靠性指标进行评定 ,避免了MML方法在遇到无失败单元时不适用的缺陷 ,在利用地面试验信息方面有其明显优势 ;运用Bayes方法对改进型导弹的飞行可靠性指标进行评定 ,将不同试验阶段的多源试验信息作为验前信息 ,扩大了信息量 .最后 ,对两种方法在工程应用上遇到的问题进行了讨论 ,并给出了解决方法 .     

中厚板表面质量分析

在对济钢中厚板各种表面缺陷产生原因和几率进行综合分析的基础上 ,将缺陷分为 3类 :A类(折叠、麻点、划伤等 )、B类 (夹杂、结疤、分层 )、C类 (裂纹 ) ,重点对裂纹缺陷进行探讨 ,并提出了相应的改进措施。     

绿色食品与绿色包装

介绍了食品绿色包装与环境保护的关系，探讨了食品绿色包装材料的选择及应用，食品绿色包装设计及市场价值等方面的内容。     

高雷诺数下双圆柱绕流的数值模拟

本文使用表面涡法研究高雷诺数下不同排列方式双圆柱绕流的流动状态，计算了双圆柱在并列、串列及级列的情况下的各种流动结构，涡街的变化及作用在圆柱上的受力情况。本文结果清楚地描述了双圆柱绕流复杂的流动状况，计算结果与实验显示的流动状况十分相似，斯特罗哈数和阻力系数与实验结果符合得很好。     

构造作用对油气生成和运聚的影响

有机质从埋藏开始，就处于极其复杂的地球物理化学场中，环境提的能量，一是热量，二是机械能，机械能，主要是通过机械力作用传递给系统的，另外还以机械波的形式赋予系统一定的机械能。当发生断褶构造运动时，机械力对油气运移的影响尤为突出，它经能量的迁移转化，促成了包括机械力降解和地应力驱动等一系列的连锁反应，制造了一次次高效的成油（生运）事件，本文以突变论为着眼点，按照改造控制建造的思路，大胆提出构造运动制造生排烃事件，成就含油气系统的假说。     

论科学化包装

从包装的基本功能以及我国食品(商品)包装的现状和存在问题出发,论证了科学化包装势在必行,并提出了科学化包装的具体方法。     

医用聚氯乙烯材料的表面光接枝改性

研究了在不排氧氛围下 ,紫外光照射 ,以二苯甲酮 (BP)为光引发剂 ,甲基丙烯酸缩水甘油酯(GMA)在医用聚氯乙烯 (PVC)薄膜表面的气相接枝聚合。探讨了反应条件对接枝结果的影响 ,并用正交法指出了影响因素的显著性。用傅立叶红外 (FT- IR)、水接触角作为接枝改性结果的表征。FT- IR谱图表明 GMA已接枝到 PVC膜表面。水接触角由接枝前的 78°下降到 5 4°     

The effect of doubly tapered strut morphology on the plastic yield surface of cellular materials

Although the literature on the mechanics of cellular materials is vast, there is no theoretical model to account for the effects of axial yielding of struts aligned to the applied loading direction on the plastic yield surface under multiaxial loading conditions. An anisotropic hexagonal model having tapered strut morphology is developed to show these effects on the plastic yield surface under multiaxial tensile loading condition. This model covers several types of cellular structure such as two-dimensional (2D) hexagonal and square cellular materials, and three-dimensional (3D) hexagonal and rhombic cellular materials of rod-like columnar structure. A tetrahedral element with tapered strut morphology is also used for a foam model to illustrate these effects on the yield surface under axisymmetric loading condition. Plastic collapse due to bending moment in the inclined struts is a dominant mode. However, under multiaxial tensile loading, the collapse due to axial yielding of struts parallel to the loading direction is found to be an important mode. The shape of plastic yield surface was found to depend not only on relative density but also on the strut morphology.     

十二酰胺丙基二甲基羟乙基氯化铵与十二烷基硫酸钠水溶液的表面吸附和胶束形成

利用十二酰胺丙基二甲胺和氯乙醇反应 ,合成了十二酰胺丙基二甲基羟乙基氯化铵 (DDHA)阳离子表面活性剂 ,将其与十二烷基硫酸钠 (SDS)以不同摩尔比进行混合 ,测定了混合系统的表面张力 ,计算了单一系统和混合系统的饱和吸附量、分子最小截面积 ,表面层和胶束中 DDHA的摩尔分率及分子间相互作用参数 ,目视观察了混合系统的浑浊情况。结果表明 :在降低γcmc和 cmc方面 ,DDHA SDS混合系统有协同效应 ,表面层和胶束的组成与二组分配比有关 ,但是非对称的 ,等物质的量混合物中 ,DDHA在胶束和表面层中具有较大的摩尔分数。DDHA与 SDS在实验测定的各混合系统中都不出现混浊