Landfill leachate treatment by MBR： Performance and molecular weight distribution of organic contaminant

A membrane bioreactor (MBR) with an air-lift bioreactor and gravity flow is applied to treating landfill leachate. More than 99% of BOD5 (biochemical oxygen demand for five days) removal effi-ciency is achieved with less than 35 mg/L of BOD_5 in the effluent at less than 1.71 kg BOD5/m~3·d of BOD_5 loading rate. When DO (dissolved oxygen) is maintained at the range of 2.3―2.8 mg/L and the loading rate of NH_4~ -N (ammonium nitrogen) is kept at 0.16― 0.24 kg NH_4~ -N/m~3·d, the NH_4~ -N in the effluent is less than 15 mg/L. However, compared with high removal rates of BOD_5 and NH_4~ -N, the removal effi-ciency of soluble chemical oxygen demand (SCOD) varies between 70% and 96%. The investigation of molecular weight (MW) distribution has been carried out by the gel permeation chromatography (GPC) so as to understand the fate of organic matters in the MBR treating of landfill leachate. Results indicate that organic matters of the landfill leachate are composed of a high MW fraction (MW of the peak, MWp = 11480―13182 Da) and a low MW fraction (MWp = 158―275 Da). The high MW fraction is not biode-gradable, but can be decreased with microfiltration membrane. The most of the low MW fraction is bio-degradable, but the residue of the low MW fraction is able to permeate through the membrane, thus re-sulting in high SCOD in the effluent of the MBR.     

PMO与两可亲核试剂的双重反应性——微扰理论在有机化学中的应用研究Ⅷ

本文介绍了用于分析电子授-受反应过程的普通微扰方程,通过考查反应过程的电荷控制和轨道控制,从而半定量地解释和预测了具有双重反应性的两可亲核试剂的反应选择性。 我们曾用分子轨道微扰理论的普通方程(GP方程)半定量地解释了某些环加成反应的反应性、周边选择性、次级效应以及烯烃和苯环的亲电反应性,本文试用类似的考虑方法,分析电子授-受过程的电荷控制和轨道控制,从而解释和预测具有双重反应性的两可亲核试剂的反应选择性。     

高分子量PAN聚合体溶解工艺条件

用不同的溶解方法对高分子量PAN聚合体进行了溶解实验，结果表明：采用高速剪切乳化机进行溶解的方法能够显缩短溶解时间，搅拌的助溶作用也很明显．溶解温度、时间、浓度等工艺参数对溶液的性能也有影响．     

Micro-Mechanical Behavior of HOPG in Nano-Indentation

The mechanical behavior of highly oriented pyrolyti c graphite (HOPG) has been investigated in this paper, by simulating a machining p rocess in a nano-indent test with the method of molecular dynamics (MD) and by doing an experiment directly using the probe tip of atomic force microscope (AFM ) as tool. The characteristics and properties of graphite crystal lattice are di scussed firstly, then, three potentials are selected for different interaction b etween graphite atoms according to the graphite prope...     

一类一般线性聚亚苯基图Q_h的Wiener拓扑指标

文章给出了一类一般线性聚亚苯基图hQ的Wiener拓扑指标的线性递推公式,通过求解差分方程而得到了它的Wiener拓扑指标的精确表达式。     

高转动态对Franck—Condon因子的影响

在核运动的波动方程中,计入了分子的转动因素时,得出与转动量子数有关的波函数表达式。从而可计算含转动自由度时具有重要意义的Franck-Condon因子。     

药物分子剖面特性的计算机图形表达

将理论化学与计算机图形学相结合，分析药物分子剖面的势场分布特性。将理论化学计算所得数据，形成空间分布，经过投影，坐标计算，投影点追踪，系统的搜索，在计算机上绘出其势场特性分布图形，并用ＰＡＳＣＡＬ语言形成一实用性强，功能完善的软件。     

微波辐照对减压渣油化学组成的影响

用频率为2450MHz的微波对胜利、孤岛减压渣油进行了辐照。辐照时，样品的体温底低于80℃，实验结果表明辐照过程中样品发展了化学变化。减压渣油和正庚烷沥青质的VPO平均相对分子质量都减小了。减压渣油及其正庚烷沥青质的FT－IR中波数为1380cm^-1，1460cm^-1和1600cm^-1的吸收峰的峰高和峰面积都发生了相对变化。对辐照前后的减压渣油进行了六组分分析。结果表明六组分中重组分减少，轻组分增加。最后，分析了减压渣油及沥青质在微波辐照下发生化学变化的作用机理。     

Y型分子筛吸附分离果葡糖浆研究

果葡糖是一种新糖源.第一代果葡糖浆含糖量为70%,其中果糖占糖成份的42%,它的甜度相当于蔗糖,是目前应用较广的糖浆.但是由于果糖的含量较低,糖浆容易出现结晶,贮运和使用都不方便。70年代美国UOP公司应用分子筛从第一代果葡糖浆分