聚合物纳米复合材料微孔发泡研究进展

综述了几种聚合物纳米复合材料微孔发泡方法和研究进展．分析了纳米材料对聚合物微孔发泡的影响，讨论了纳米粒子在聚合物微孔发泡中的作用机理，并对聚合物纳米微孔发泡材料的研究及应用前景进行了展望。     

马氏体相变形核机制的研究

应用JEM-2100电镜、QUANTA-400环扫电镜对钢中马氏体相变的形核进行了观察,发现马氏体不仅可在奥氏体晶内形核,而且可在晶界、相界面等处形核。认为马氏体是在缺陷处依靠结构涨落、能量涨落形核,是晶格重构的过程,不是切变过程。研究计算了马氏体晶核的临界尺寸和形核功。     

Study on the Crystallization Mechanism of Spectinomycin Dihydrochloride

Dilutionisonekindofcrystallizationsthatiswidelyusedintheproductionofpharmaceuticals ,especiallyantibi otics.Dilutionhasmanyadvantagessuchashigherthrough putsbypreparingveryconcentratedinitialsolutions,loweroperatingtemperatureforheat labilesubstancesandbetterpu rificationasthemotherliquorretainsundesiredimpurities[1] .Oneofthecharacteristicsofdilutionisthatthesolventcom positionvarysastheprocessproceeds.Thesolventcomposi tionhasinfluenceonnotonlythenucleationratebutalsotherelativegrowthrateofe…     

Metastable state of clindamycin phosphate in cooling crystallization

The metastable state and nucleation kinetics of clindamycin phosphate （CP） in cooling crystallization were studied by metastable zone width （MZW） method and induction time method. By correlating the MZW experi- mental results with temperature, agitation rate and cooling rate, it is found that the correlation result shows good agreement with the change trend of MZW. The critical nucleation parameters were evaluated based on the classical theory of nucleation; both the interfacial tension and the radius of critical nucleus increased with the decrease of rela- tive supersaturation. The effect of supersaturation on the nucleation rate was analyzed. It is indicated that the new phase formation of CP is governed by mononuclear mechanism.     

核态沸腾中汽化核心密度的分形分布

本文首先回顾了在核态沸腾传热中影响汽化核心密度分布的几个关键因素,然后运用分形理论讨论了加热壁面微结构和汽化核心密度之间的关系并分析了两个核态沸腾实验中汽化核心密度的数据。一个实验是考察加热壁面在老化过程中汽化核心密度的变化,另一个实验是考察两个不同材料制成的加热壁面上汽化核心密度的差异。实验数据分析结果表明汽化核心密度与最小成核半径之间呈分形关系。不同加热壁面对应不同的分形维数,分形维数是一个定量描述加热壁面状况的参数。     

核态沸腾中汽化核心密度的分形分布

本文首先回顾了在核态沸腾传热中影响汽化核心密度分布的几个关键因素，然后运用分形理论讨论了加热壁面微结构和汽化核心密度之间的关系并分析了两个核态沸腾实验中汽化核心密度的数据。一个实验是考察加热壁面在老化过程中汽化核心密度的变化，另一个实验是考察两个不同材料制成的加热壁面上汽化核心密度的差异。实验数据分析结果表明汽化核心密度与最小成核半径之间呈分形关系。不同加热壁面对应不同的分形维数，分形维数是一个定量描述加热壁面状况的参数。     

在金属表面络合网格状高分子膜实现滴状冷凝的MD模拟研究

提出了在铜表面络合上一种网格状高分子膜来实现水蒸汽滴状冷凝的新模型。预计这种单分子层的高分子膜可以被大片的配位键牢牢地粘附在金属表面上,并具有可自修复的特性,因而可望获得超长使用寿命和较高传热效率的滴状冷凝表面。根据相关的成膜或成滴的判据,用分子动力学模拟方法计算了水分子的内聚能和表面的吸附能。结果表明,在这种网格状高分子膜的表面上可以实现滴状冷凝。并且,通过观察粒子的平衡位型分布,可以看到网格状高分子中的大环结构可能起到核化中心位的作用。     

圆锥形收敛流道中流体动能的理论解析：

根据塑料发泡中复杂流场流体动能气泡成核理论,对圆锥形收敛流道中的流体动能进行了理论解析。通过圆锥形收敛流道的流场分析,经过大量推导,得出了该种流道中流体剪切能、流体延伸能及流体总动能的理论解析。可以进一步用来定量分析圆锥形收敛流道中塑料熔体的气泡成核。     

Investigation of Fogging on Glass Display Cases at the Royal Ontario Museum

ABSTRACT

Shortly after a major renovation at the Royal Ontario Museum, it was noticed that the glass panels in many of the new display cases exhibited fogging or hazing on the surface, sometimes in very specific patterns. Cleaning removed the fogging temporarily, but it began to reappear within 12 months. An investigation of fogged glass panels in display cases was undertaken to understand the source of the fogging and to develop an appropriate cleaning method. This included the analysis of residues from glass panels in several galleries, and surface imaging and compositional analysis of glass panels. The fogging residues on the glass panels consist mainly of sodium salts of organic acids and inorganic anions. Sources of the sodium in the residues include air particulate matter and the glass itself. The organic acids and inorganic anions that form salts with the sodium cations likely originate from volatile organic compounds (VOCs) and particulate matter in the air. Examination of the fogging patterns on the glass panels revealed that the sodium salts grow on marks made during cleaning attempts and the manufacturing process. These cleaning and manufacturing marks contain greasy residues that encourage crystal growth. Because of the variation in surface cleanliness, panels with more cleaning and manufacturing residues appear to be heavily fogged while those with less may appear to be unfogged in the museum display cases. A cleaning protocol was tested on two of the glass panels, and was found to remove all traces of grease and fogging residue.     

基于三垂面上形核的润湿角

对三垂面基体上非自发形核进行了研究. 根据非自发形核的条件,对临界形核半径和临界形核功进行了推导,得到了临界形核功与润湿角的数学表达式.结果表明,临界形核功仅与润湿角有关,说明润湿角在非自发形核中起非常重要的作用.对形核润湿角进行的讨论表明了,与自发形核相比,非自发形核具有更小的临界形核功.