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Fe3O4/ chitosan magnetic microspheres of 50 to 80 滋m were prepared using the inverse phase emulsion dispersion and chemical crosslinking technology, and then modified with ethylenediamine for use in the adsorption of heavy metal ions. The adsorption properties of the modified Fe3O4/chitosan toward Cu2+, Cd2+ and Ni2+ were investigated. It was found that the adsorption capacities of Cu2+ and Ni2+ increased with pH, and a maximum adsorption for Cd2+ occurred at pH=3. The saturated adsorption capacities calculated by Langmuir isotherms were 54.3 mg·g-1 for Cu2+, 20.4 mg·g-1 for Cd2+, and 12.4 mg·g-1 for Ni2+, respectively. The adsorption kinetics were well described by pseudo-second-order equation models. The experimental results showed that the Fe3O4/chitosan modified with ethylenediamine presented higher adsorption selectivity for Cu2+ than for Cd2+ and Ni2+ in all studied pH ranges. 相似文献
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A relationship between the X-H (X = N, O, C, and so on) equilibrium bond length in a Morse oscillator and the X-H stretching overtone frequency shifts is obtained theoretically. We use the equation to discuss the empirical linear relationships that have been proposed for heterocyclics, alkanes and fluorinated benzenes. On the other hand, a unified relationship between the X-H bond angles and the experimental quantities (ω(?) and the coupling strength λ) is also presented for XH2, XH, and XH4 molecules or molecular fragments. Calculations of X-H bond angles for a number of molecules show that the results from our equations are in excellent agreement with the experimental values. Also we can extract the information of relative magnitude of bond coupling force field. 相似文献
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铜在氨水介质铁氰化钾抛光液中CMP的电化学行为研究 总被引:3,自引:1,他引:2
应用电化学测试技术研究了介质浓度(包括pH值)和成膜剂浓度对铜表面成膜及铜抛光过程的影响,探讨了成膜厚度及其致密性与抛光压力、抛光转速的关系,考察了压力及转速对抛光过程的作用,找出影响抛光过程及抛光速率的电化学变量。用腐蚀电位及腐蚀电流密度的变化解释了抛光过程的电化学机理,通过成膜速率及除膜速率的对比得出抛光过程的控制条件。证明了在氨水溶液介质中、以铁氰化钾为成膜剂、纳米γ-Al2O3为磨粒的抛光液配方是可行的,其抛光控制条件为压力10psi、转速300r/min。 相似文献
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Cooper考虑一对电子在一个安稳的费米球面上相互作用着,指出这种相互作用是由声子和屏蔽库仑场导致的,在电子间存在一种净的吸引作用,结果这对电子能够形成一个束缚态.我们给出的是对于元素之中有化学键的形成,甚至电了发生了转移,电负性高的元素得到了电子,电负性低的元素失去了电子时退化费米气体中的束缚电子对的描述. 相似文献
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研究了混合芳酰氯与双酚A界面共缩聚反应的规律性。结果表明:反应条件相同,合成聚酚酯需要比聚碳酸酯长得多的时间才能达到分子量最高值;收率与时间的关系,则与合成聚碳酸酯相同(反应数分钟后,就可以接近收率的最高值,但此时分子量颇低)。 从反应时限、收率、分子量三者的变化关系,发现了反应过程中聚合物的界面降解现象。界面降解的特点是失重虽多,而分子量下降极微,甚至没有下降。 酰氯-双酚配合比对分子量、收率影响的曲线图形与前报合成聚碳酸酯所得结果相仿,但分子量曲线的最大值转移至双酚过量之侧。而且,最大值的位置,在一定范围内随碱用量增高而向双酚过量愈甚处偏移。 反应物料乳液经稀释及导电试验证明系水/油型。 观察了有机相酰氯浓度对链增长速度及最终分子量的影响。结果表明,酰氯浓度愈大,短时间(≤1小时)产物的分子量愈高,而且分子量达到最高值所需的时间也愈短。每种浓度所能达到的最高分子量与酰氯浓度间的关系曲线,在0.4 克分子/升左右出现最大值。 碱用量、碱浓度及双酚浓度对分子量的效应和前报关于聚碳酸酯合成时所呈现的现象完全相似。 用红外光谱测定了各种反应条件下所得共缩聚物的对-与间-苯二甲酸的组成比例。 相似文献