交联网络和浓溶液中高分子链运动的NMR研究Ⅲ.质子自旋-晶格弛豫时间与凝胶和浓溶液体系中高分子链段的运动

用自旋－晶格弛豫时间（Ｔ１）研究了溶胀的交联聚丙烯酰胺－丙烯酸网络和线型聚苯乙烯溶液中质子的弛豫行为。交联网络中，随着交联度增大，Ｔ１ＣＨ／Ｔ１ＣＨ２的值由１．１７逐渐趋近于１；而线型聚苯乙烯溶液中，Ｔ１ＣＨ／Ｔ１ＣＨ２的值由最稀浓度下的１．７过渡到１。说明在交联网络中，交联度很低时，链段的运动已经相当受约束；但交联度很大时，充分溶胀的交联网络中链段运动仍有一定自由度。而在线型高分子浓溶液中，链段的运动严重受阻，导致自旋扩散效应非常完全，彻底平均掉了各质子间Ｔ１时间的差异。     

用共振电离飞行时间质谱仪分析土壤中超痕量气态金

采用激光共振电离飞行时间质谱技术（简称ＲＩＳ－ＴＯＦ技术）对土壤中超痕量气态金的含量进行了分析研究。ＲＩＳ－ＴＯＦ谱仪具有极高的灵敏度和很强的选择性，避免了对样品的预富集过程。本文给出了该谱仪对金元素的检测限和６５个土壤中气态金样品的分析结果，以及用中子活化法随机抽样检查的结果。     

精制煤液化中油加氢裂化制取喷气燃料的研究

在实验室固定床反应装置上,选用Mo-Ni-P/Si-Al工业催化剂,对精煤液化中油进行了加氢裂化制取喷气燃料的实验。考察了反应温度、空速对芳烃加氢转化及产品馏分分布的影响。通过加氢裂化,降低了油品芳烃含量,提高了喷气燃料馏分的收率。在总压为15MPa,反应温度为350—360℃,空速为0.8—1.0h~(-1)条件下,获得了芳烃含量低于10w%的低结晶点的优质喷气燃料产品。并对煤液化中油制取的喷气燃料的组成和性质进行了分析和评价。     

富镧和富铈混合稀土贮氢电极的性能

富镧和富铈混合稀土贮氢电极的性能＊赵东江马松艳（黑龙江省绥化师专化学系绥化市１５２０６１）关键词混合稀土贮氢电极性能中图分类号Ｏ６４６．５４混合稀土贮氢合金具有良好的电化学特性和较低的价格，成为贮氢电极研究的主要对象，已经开发出许多实用的电极材料［１...     

Growth of Ni2Si by rapid thermal annealing: Kinetics and moving species

The growth kinetics is characterized and the moving species is identified for the formation of Ni₂Si by Rapid Thermal Annealing (RTA) of sequentially deposited Si and Ni films on a 100 Si substrate. The interfacial Ni₂Si layer grows as the square root of time, indicating that the suicide growth process is diffusion-limited. The activation energy is 1.25±0.2 eV in the RTA temperature range of 350–450° C. The results extend those of conventional steady-state furnace annealing quite fittingly, and a common activation energy of 1.3±0.2 eV is deduced from 225° to 450° C. The marker experiment shows that Ni is the dominant moving species during Ni₂Si formation by RTA, as is the case for furnace annealing. It is concluded that the two annealing techniques induce the same growth mechanisms in Ni₂Si formation.     

Thermal decomposition of Cd(CH3COO)2·2H2O studied by a coupled TG-DTA-MS method

The thermal decomposition of cadmium acetate dihydrate in helium and in air atmosphere has been investigated by means of a coupled TG-DTA-MS method combined with X-ray diffraction analysis. Dehydration of Cd(CH₃COO)₂·2H₂O is a two-stage process with Cd(CH₃COO)₂·H₂O as intermediate. The way of Cd(CH₃COO)₂ decomposition strongly depends on the surrounding gas atmosphere and the rate of heating. CdO, acetone and CO₂ are the primary products of decomposition in air. In helium decomposition goes by two parallel and consecutive reactions in which intermediates, Cd and CdCO₃, are formed. Metallic cadmium oxidizes and cadmium carbonate decomposes giving CdO. Some of the metallic cadmium, depending on the heating rate and the concentration of oxygen, evaporates. Acetone is partially oxidized in secondary reactions with oxygen. This revised version was published online in July 2006 with corrections to the Cover Date.     

Y2O3薄膜处理对3Cr25Ni7N合金的抗高温氧化性能的影响

采用电沉积-热解法在3Cr25Ni7N合金表面制备了Y2O3薄膜,并研究了薄膜处理对合金在1000℃空气中的抗高温氧化性能的影响。氧化动力学曲线、SEM及XRD分析结果表明,Y2O3薄膜处理使合金表面氧化膜以尖晶石结构为主,氧化膜致密,有效地抑制了Cr2O3的挥发反应,且氧化膜与基体的附着性好,因此合金在高温下的抗氧化性能得到提高,这与氧化钇薄膜在较低温度下抗高温氧化性能提高的机制是不同的。在不同温度下,Y2O3薄膜处理均可以有效提高合金的抗高温氧化性能。