琼脂凝胶中形成铬酸铅周期性沉淀的机理研究

选择硝酸铅和铬酸钾作为相互扩散的反应物以形成铬酸铅在琼脂凝胶中的周期性沉淀．分别在光照和黑暗中对六种不同浓度的硝酸铅溶液进行了实验．根据实验现象对周期性沉淀的形成提出了可能的机理．认为光辐射可使铬酸铅部分电离，从而减慢了胶核成长速率，有利于汇聚成带．     

关于Liesegang环形成机理的研究

本文研究了Ｌｉｅｓｅｇａｎｇ环的形成，受到两扩散电解质溶液的浓度比、离子浓度积及光照等条件影响。侧重对成环的微观汇聚过程进行了探讨。     

加强工科院校人文素质教育的思考

加强工科院校人文素质教育势在必行，为此，必须确立专业科技教育与人文素质教育并重的教育思想，重视人文素质教育，努力探索，并构建符合本校实际的人文素质教育的模式。     

The Manufacture of Aluninium Sulfate from Dikite

本文叙述了用地开石制造纯硫酸铝的过程,对矿石煅烧、硫酸铝浸出、浓缩结晶的工艺条件进行了讨论。实验结果表明此项生产成本低、无三废,具有一定的开发利用价值。     

Transport of airborne particulate matters originating from Mentougou, Beijing, China

In this study, a coupled regional air quality modeling system is applied to investigate the time spatial variations in airborne particulate matters （PM10）, originating from Mentougou to Beijing municipal area in the period of April 1-7, 2004, and the influences of complex terrain and meteorological conditions upon boundary layer structure and PM10 concentration distributions. An intercomparison of the performance with CALPUFF against the observed data is presented and an examination of scatter plots is provided. The statistics show that the correlation coefficient and STD between the modeled and observed data are 0.86 and 0.03, respectively. Analysis of model results illustrates that the pollutants emitted from Mentougou can be transported to Beijing municipal area along certain transport pathways, and PM10 concentration distributions show heterogeneity characteristics. Contributions of the Mentougou sources to the PM10 concentrations in Beijing municipal area are up to 0.1-15 μg/m^3.     

Solid‐State Photochromic Behavior and Thermal Bleaching Kinetics of Two Novel Pyrazolone Phenylsemicarbazones

Two novel photochromic compounds, 1,3‐diphenyl‐4‐benzal‐5‐hydroxypyrazole 4‐phenylsemicarbazone ( 1 a ) and 1,3‐diphenyl‐4‐(4‐nitrobenzal)‐5‐hydroxypyrazole 4‐phenylsemicarbazone ( 2 a ), are synthesized and characterized by elemental analysis, mass spectrometry, FTIR spectroscopy, and ¹H NMR spectroscopy. Their properties, including photochromic behavior, fluorescence properties, and thermal bleaching kinetics, are investigated. The results show that the two compounds exhibit improved photochromic performance in coloration and thermal bleaching rates, excellent photostability, high fatigue resistance, and reversible fluorescence switching properties in the solid state in comparison to reported pyrazolone thiosemicarbazones. The thermal bleaching process obeys first‐order kinetics. Bleaching of powders at 130 °C is completed within 90 s for 1 b (the colored isomer of 1 a ) and 150 s for 2 b (the colored isomer of 2 a ). The activation energy for the thermal bleaching process is determined to be 69 and 95 kJ mol^?1, with frequency factors of 9.5×10⁷ and 9.4×10¹⁰ s^?1 for 1 b and 2 b , respectively.     

分段均匀弦振频率的精确计算

本文给出分段均匀弦的振动频率的准确算法。由于非均匀弦可用分段均匀弦逼近,故该法亦提供非均匀弦振动频率的一种有效的近似算法。     

9-(4-溴丁基)-9H-咔唑的相转移催化合成、表征及室温磷光性能研究——推荐一个大学化学综合实验

推荐了一个大学化学综合实验"9-(4-溴丁基)-9H-咔唑的相转移催化合成、表征及室温磷光性能研究"。实验利用相转移催化合成9-(4-溴丁基)-9H-咔唑分子,采用核磁共振、高分辨质谱和红外光谱对其分子结构进行表征,并利用紫外-可见吸收光谱、稳态/瞬态荧光光谱和密度泛函(DFT)理论计算对其室温磷光性能进行研究。本综合实验涵盖了有机化学、分析化学、物理化学、仪器分析以及理论化学的知识点,建议纳入化学专业高年级综合实验课程。