Deformation of styrene—divinylbenzene copolymers and hypercrosslinked polystyrenes during solvent adsorption and desorption

An automated procedure was developed for monitoring fast changes in the size of spherical samples of polymers during their contact with a solvent or drying. The kinetics of bulk deformation in these processes was studied for a series of cross-linked polymers, viz., gel-type and porous styrene—divinylbenzene copolymers and poly(divinylbenzenes), and hypercrosslinked polystyrenes. Gel, macroporous, and hypercrosslinked polystyrenes are substantially different in the rate, mechanism, and degree of swelling, which is associated with the principal differences in their physical structures. An unusual effect of a sharp decrease followed by a temporary increase in the volume of porous polystyrene and poly(divinylbenzene) materials were observed during desorption (evaporation) of organic solvents. Water desorption is accompanied by an excessive bulk compression of porous granules giving rise to negative deformations, which gradually relax to the state equilibrium for the dry polymer. The results of dynamic desorption porometry (for water desorption) are indicative of a bimodal size distribution of micropores in hypercrosslinked polystyrene. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 467–476, March, 2007.     

萃取色谱法富集原子吸收法测定环境水中超痕量金属元素──两种萃取剂的比较

本文研究并比较了分别以８－羟基喹啉和巯基苯骈噻唑为萃取剂，以活性硅胶为载体的柱式萃取色谱法对环境水中Ｚｎ、Ｃｕ、Ｐｂ、Ｃｄ、Ｆｅ、Ｃｏ、Ｎｉ和Ｍｎ的最佳富集和洗脱条件。实验证明，后者明显优于前者。以巯基苯骈噻唑为萃取剂的色谱柱对金属元素的吸附具有快速、完全、寿命长和重现性好等特点。在ｐＨ＝７～８之间回收率可达９８％以上，富集倍数为２００倍。     

Electron-stimulated desorption of D (H) from condensed D2O (H2O) films

The electron-stimulated desorption (ESD) of D⁻ and H⁻ ions from condensed D₂O and H₂O films is investigated. Three low-energy peaks are observed in the ESD anion yield, which are identified as arising from excitation of ²B₁, ²A₁ and ²B₂ dissociative electron attachment (DEA) resonances. Additional structure is observed between 18 and 32 eV, which may be due to ion pair formation or to DEA resonances involving the 2a₁ orbital. The ion yield resulting from excitation of the ²B₁ resonance increases as the film is heated. We attribute the increase in the ion yield to thermally induced hydrogen bond breaking near the surface, which enhances the lifetimes of the excited states that lead to desorption.     

三角帆蚌对水体Cr,Pb和Cd的净化与吸收

三角帆蚌（Hyriopsis cumingii Lea）对水体Cr,Pb,Cd污染有明显的净化能力，持续处理12d，能使水体Cr,Pb,Cd含量分别下降83％，77．6％和72％。蚌体的斧足、鳃、外磁膜、体表粘液、肝脏、肠道和生殖腺等组织对3种污染物的吸收和富集作用不尽相同，其中分别以体表粘液、鳃和肝脏最为显著。3种污染物进入蚌体的速度很快，其组织吸收量一般在第3天即可达到较高水平。进入蚌体的污染物，可在组织转移和重新分布。研究结果为生物治理Cr,Pb,Cd等重金属污染积累了资料。     

石墨-六角氮化硼微晶混合物与水高压反应产物分析

 利用球磨法制备石墨-六角氮化硼微晶混合物，并在6.1 GPa、800~1 500 ℃条件下与水进行高压反应，以便研究用水作触媒合成B-C-N三元化合物的可能性。通过对反应产物的XRD、XPS谱分析发现：高压下随着温度的升高，反应产物中出现再结晶石墨，其晶化程度逐渐提高；但没有出现再结晶六角氮化硼，也未出现立方氮化硼。在球磨不充分条件下，石墨-六角氮化硼混合物的XRD谱没有完全弥散，它们与水高压反应时，能观察到石墨与立方氮化硼分别结晶的现象，但都没有形成B-C-N晶化结构。     

几种旱生植物水分生理特性的比较研究

本文对梭梭(Halorylon ammodendron)等几种典型荒漠旱生植物在干旱环境下体内含水量、相对合水量、水分饱和亏缺、自由水、束缚水、水势、离体枝叶吸水速率等的变化及其与植物抗旱的关系进行了比较研究。     

中高温工质在蒸发器中的换热模拟分析

本文采用分布参数的方法,建立了水源热泵中普遍采用的壳管式蒸发器稳态数学模型.通过中高温水源热泵试验台的实验数据同模拟计算结果的对比,验证了数学模型的准确性。应用此数学模型对中高温工质HTR01、HTR02及R134a在蒸发器典型制热运行工况,进行了模拟计算。得出了三种工质制冷剂侧换热系数沿管长的变化关系并对三种工质的换热性能进行了对比分析,为采用中高温工质的水源热泵换热器设计提供了参考依据.