液化气铜片腐蚀原因及解决措施

本文就引起液化石油气（LPG）铜片腐蚀不合格的原因进行了分析，对JX－1A精脱硫剂工业应用效果进行了探讨，结果表明JX－1A精脱硫剂在解决了LPG铜片腐蚀不合格方面有很好的效果。     

Complete oxidation of methane at low temperature over Pt and Pd catalysts for the abatement of lean-burn natural gas fuelled vehicles emissions: influence of water and sulphur containing compounds

The catalytic activity of fresh Pd and Pt catalysts supported on γ-alumina in the complete oxidation of CH₄ traces under lean-burn conditions was studied in the presence or the absence of water or H₂S. Steam-aged catalysts were also studied in order to simulate long-term ageing in real lean-burn natural gas fuelled vehicles (NGVs) exhaust conditions. Without water or H₂S added to the feed, Pd catalysts exhibit a superior catalytic activity in methane oxidation compared to Pt ones, whatever the catalysts were fresh or aged. The addition of 10 vol.% water vapour to the feed strongly affects the activity of the fresh Pd catalyst, thus being only slightly more efficient than the fresh Pt one. H₂S has a strong poisoning effect on the catalytic activity of Pd catalysts, while Pt catalysts are more resistant. The fresh H₂S-poisoned Pd/Al₂O₃ catalyst was studied by TPD in O₂/He. Poisoning species decompose above 873 K as SO₂ and O₂ in relative concentrations consistent with the decomposition of surface sulphate species. However, a treatment in O₂/He at temperatures as high as 923 K does not allow the complete regeneration of the catalytic activity of H₂S-poisoned Pd/Al₂O₃. A mechanism involving the poisoning of PdO by sulphate species is proposed. Different diffusion processes by which these sulphate species can migrate back and forth between PdO and the support, depending on the experimental conditions, are suggested.     

跳时序列与跳频序列的性能比较

通过对传统通信中跳频序列与超宽带无线电通信中跳时序列的分析比较,得出了两者间相关性能的关系,论述了两者之间的差异,并总结出了将跳频序列转换成为跳时序列的方法,从而为超宽带无线电通信中跳时序列的构造提供了参考。     

Crystallization and thermoelectric behavior of conductive-filler-filled poly(ε-caprolactone)/poly(vinyl butyral)/montmorillonite nanocomposites

Crystallization and thermoelectric properties of poly(ε-caprolactone) (PCL)/poly(vinyl butyral) (PVB)/montmorillonite (MMT) nanocomposites containing carbon black (CB) have been studied as a functions of a small amount of amorphous PVB content and a wide range of molecular weight of PVB. X-ray diffraction data of PCL/PVB/MMT nanocomposites indicates most of the swellable silicate layers are exfoliated and randomly dispersed into PCL/PVB system. The band spacings of PCL spherulites in PCL/PVB/MMT nanocomposites decrease with increasing PVB content, and this indicates that increasing the PVB content greatly shortens the period of lamellar twisting. The presence of 1 wt% MMT and higher molecular weight of PVB also shorten the period of PCL lamellar twisting. Nucleation and crystallization parameters, such as growth rate G and Avrami exponent n, can be determined by using POM and DSC isothermally crystallized at 41 °C. For samples with the same CB content, the intensity of positive temperature coefficient (PTC) (I_PTC, defined as the ratio of peak resistivity to resistivity at room temperature) of the nanocomposites was increased as the content and the molecular weight of PVB increases. The change of the PTC property related to the morphological difference (i.e. period of lamellar twisting) in the nanocomposites can be discussed.     

Hydrolysis of Fe(OH)SO4 in the presence of metallic iron

Hydrolysis of Fe(OH)SO₄ was carried out in the presence of metallic iron in order to prevent the formation of iron(III) oxides with strongly bonded sulphate. Under the conditions of the experiment, the products were found to be mixtures of ?-Fe₂O₃ and α-FeOOH. The occluded sulphate, if any, could be easily washed out with water. The hydrolysis reaction passes through an equilibrium state before coming to completion. The entropy with enthalpy of the hydrolysis corresponding to the equilibrium state were found to be 4 e.u. and 0·5 kJ/mol, respectively. The activation energy of the hydrolysis reaction was found to be 21 kJ/mol.     

The effects of glycol methacrylate as a dehydrating agent on the dimensional changes of liver tissue

The dimensional changes of liver sections during the course of processing with glycol methacrylate (GMA) or with ethanol are described. Tissue processing with ethanol served as a control. During prolonged processing steps (24 h each), linear shrinkage of tissue specimens dehydrated with GMA at room temperature was 13.2%. Subsequent infiltration with GMA resulted in trivial swelling, and polymerization in slight shrinkage (2.3%). In comparison, processing with cold GMA resulted in shrinkage during dehydration (about 10.8%), a slight swelling in pure GMA, followed by shrinkage during polymerization (2.2%). Short routine processing schedules resulted in similar shrinkage/swelling patterns, although precise values differed slightly. In all experiments, ethanolic dehydration resulted in smaller dimensional tissue changes than did GMA dehydration. The dimensional changes of tissue sections during stretching on water, mounting and drying compensated for the major part of the shrinkage manifested during processing.     

电力系统微机型产品的电磁兼容设计

从分析电力系统中电磁干扰的来源、传输途径入手，对应用于电力系统的微机型产品设计中的电磁兼容问题进行了较为系统的探讨，并提出了行有效的解决措施。     

膜-粉末炭反应器净化微污染源水

采用膜-粉末炭反应器处理微污染源水的试验结果表明,该工艺对水中的有机物具有较好的净化效果,在水温《10℃的条件下,处理可生化性很低的三家店水库水时对CODMn的去除率仍保持在65%左右;工艺对CODMn、UV254、UV410的去除效果依次增强.     

大豆乳清的预处理

针对“膜法回收大豆乳清中的生物活性物质”工艺中的预处理部分进行研究，发现絮凝离心处理分别可以去除乳清中65％左右的脂肪和90％左右的悬浮固体，袋式过滤和精密微孔管等精密过滤手段对乳清的预处理效果不佳，但是袋式过滤可以作为微滤之前的保安过滤方式，为了进一步去除乳清中的杂质和同时灭菌，微滤过程是必须的，包括絮凝离心和微滤在内的预处理过程可以在蛋白质损失率只有10％左右的情况下将悬浮固体全部去除，脂肪去除率高达90％以上。中试的试验结果验证了上述结论。     

长颗粒(柱状晶)Si3N4陶瓷的研究及进展

Si3N4陶瓷材料由于具有很好的高温性能及高的力学性能，而被广泛地用于结构陶瓷，如切削刀具等。然而，因为其对缺陷很敏感，故易受灾难性的失效。人们发展了多种Si3N4增韧陶瓷，其中自增韧由于一些优异的性能越来越受到人们的重视。在此文中，着重介绍了影响Si3N4陶瓷长颗粒(柱状晶)晶粒生成的因素，并介绍了国内外对长颗粒Si3N4晶的控制研究。