聚乳酸组织工程支架表面涂覆钙磷盐的工艺研究

提出了以聚乳酸／钙磷盐／胶原的骨组织工程支架快速成形制造的材料系统，对比了两种在聚乳酸(PLA)表面涂覆钙磷盐的工艺．一种是将聚乳酸组织工程支架浸泡在模拟体液中采用平衡反应法沉积钙磷盐；另一种是在聚乳酸薄膜上采用非平衡反应法沉积钙磷盐；系统地研究了沉积时间和沉积量、钙磷摩尔比和相结构演变的关系；通过控制反应时间和调整反应物配比获得磷酸四钙(TetCP)-PLA和无定形磷酸钙(ACP)—PLA等材料组合；并对所获得的复合材料进行生物相容性试验．对比试验证明细胞在材料表面生长良好，采用两种方法涂覆钙磷盐均改进了聚乳酸的生物相容性．     

承德低品位钙基膨润土制备高效活性白土的工艺研究

以河北承德产低品位钙基膨润土为原料 ,直接用于制备活性白土 ,成功地制备了脱色率大于 99% ,活性度为 2 18,过滤速度达 2 7 3ml/min的高效活性白土 ,并对影响活性白土质量的条件进行了探讨。     

The experimental investigation of concrete carbonation depth

Phenolphthalein indicator has traditionally been used to determine the depth of carbonation in concrete. This investigation uses the thermalgravimetric analysis (TGA) method, which tests the concentration distribution of Ca(OH)₂ and CaCO₃, while the X-ray diffraction analysis (XRDA) tests the intensity distribution of Ca(OH)₂ and CaCO₃. The Fourier transformation infrared spectroscopy (FTIR) test method detects the presence of C-O in concrete samples as a basis for determining the presence of CaCO₃. Concrete specimens were prepared and subjected to accelerated carbonation under conditions of 23 °C temperature, 70% RH and 20% concentration of CO₂. The test results of TGA and XRDA indicate that there exist a sharp carbonation front. Three zones of carbonation were identified according to the degree of carbonation and pH in the pore solutions. The TGA, XRDA and FTIR results showed the depth of carbonation front is twice of that determined from phenolphthalein indicator.     

Multiple,distinct actions of metal ions on cellular signaling processes

From a neurotoxicological perspective, we have investigated effects of Pb²⁺ and other divalent metal ions on membrane signaling by voltage‐, Ca²⁺‐ and ligand‐gated ion channels using voltage clamp and patch clamp techniques. The results from our and other studies of the effects of metal ions reported in the literature are summarized here and demonstrate that metal ions cause multiple, distinct effects on a variety of membrane signaling processes. A situation similar to that with membrane ion channels applies to the effects of metal ions on intracellular signaling. Effects on exocytosis, a resultant of highly integrated and complex intracellular signaling, indicate that Pb²⁺ is a substitute for intracellular Ca²⁺ in the triggering the fusion and release of exocytotic vesicles. Despite the relatively detailed knowledge of metal effects at the molecular level, few specific cellular targets associated with specific toxic effects of metals have been identified. Such knowledge is essential for the understanding of metal toxicity.     

Thermodynamic calculation of Sn (Ⅳ)-NH4+-Cl--H2O system

According to the principles of simultaneous equilibrium and electronic charge neutrality, the thermodynamics of Sn(Ⅳ)-NH4 -Cl- -H2O system under normal condition was calculated. Relation between all sorts of complex of Sn4 and pH was plotted. Based on thermodynamics analysis and calculation, some experiments were done to validate the relation between the total concentration of tin ion and pH in this system. The results suggest that the total concentration of ammonium and pH are the most important factors which determine whether (NH4)2SnCl6 or Sn(OH)4 exists in this system. Results further suggest when contnet of HCl is more than 6 mol/L, Sn4 in this system will be also precipitated in the form of (NH4)2SnCl6. These results lay the solid theory foundation to preindium tin oxide(ITO), from the tinny material.     

万家寨引黄工程国际Ⅰ标土建工程爆破施工中导爆管起爆网路设计方法

本文根据引黄国际Ⅰ标工程的具体情况，合理地选用导爆管起爆法，对影响导爆管起爆的因素进行了分析，得出了起爆网路雷管段别的最佳选配方案。     

小鼠精子附睾成熟过程中Ca^2＋及Ca^2＋—ATPase的研究

利用焦锑酸钾方法和电镜酶组织化学定位方法，研究了小鼠精子在附睾成熟过程中的Ｃａ＾２＋及Ｃａ＾２＋－ＡＴＰａｓｅ变化。结果发现：附睾头中的精子内元Ｃａ＾２＋或极低，而Ｃａ＾２＋－ＡＴＰａｓｅ活性极强，可能是由于Ｃａ＾２＋－ＡＴＰａｓｅ的作用将Ｃａ＾２＋从精子内排出了精子外；在附睾体中，精子Ｃａ＾２＋－ＡＴＰａｓｅ活性降低，而Ｃａ＾２＋浓度迅速上升，并且发现Ｃａ＾２＋来自于附睾管细胞；到了附睾尾部，精     

Under bump metallurgy study for Pb-free bumping

The demand for Pb-free and high-density interconnection technology is rapidly growing. The electroplating-bumping method is a good approach to meet finepitch requirements, especially for high-volume production, because to volume change of patterned-solder bumps during reflow is not so large compared with the stencil-printing method. This paper proposes a Sn/3.5 Ag Pb-free electroplating-bumping process for high-density Pb-free interconnects. It was found that a plated Sn/Ag bump becomes Sn/Ag/Cu by reflowing when Cu containing under bump metallurgy (UBM) is used. Another important issue for future flip-chip interconnects is to optimize the UBM system for high-density and Pb-free solder bumps. In this work, four UBM systems, sputtered TiW 0.2 μm/Cu 0.3 μm/electroplated Cu 5 μm, sputtered Cr 0.15 μm/Cr-Cu 0.3 μm/Cu 0.8 μm, sputtered NiV 0.2 μm/Cu 0.8 μm, and sputtered TiW 0.2 μm/NiV 0.8 μm, were investigated for interfacial reaction with electroplated Pb/63Sn and Sn/3.5Ag solder bumps. Both Cu-Sn and Ni-Sn intermetallic compound (IMC) growth were observed to spall-off from the UBM/solder interface when the solder-wettable layer is consumed during a liquid-state “reflow” process. This IMC-spalling mechanism differed depending on the barrier layer material.     

氢化物发生一原子荧光光谱法测定精锡中的微量铋

采用HCl＋HBr挥发除锡，以HG—AFS法测定精锡产品中微量铋，效果良好。     

去除稀土工业废水中Ca2+、Mg2+的研究

反渗透法作为稀土工业废水处理领域的一种高新技术应用日益广泛,如何防止稀土废水中的钙、镁污染和堵塞膜元件,是当前反渗透技术应用中的一个难点.本文研究用碳酸钠和氢氧化钠沉淀废水中的钙、镁离子,取得了一定的效果,并研究了絮凝剂的加入对沉淀快速沉降的影响.