聚氧化乙烯(PEO)/聚双酚A羟基醚(PBHE)共混体系的非等温结晶动力学

本文联系Avrami方程和Ozawa方程,得出一个适合于非等温结晶动力学过程的新的基本方程,由这个方程可获得描述非等温结晶动力学过程的某些参数,并用DSC方法,对PEO/PBHE共混体系的非等温结晶动力学进行了研究,对实验结果进行了讨论.     

毗邻沙漠地区微分博弈模型与宏观环境治理策略研究

工业化发展导致了脆弱的土地进一步沙漠化,沙漠地区政府应综合考虑经济发展与土地沙漠化导致的生态质量降低。通过构建两个沙漠化地区微分博弈模型,研究了两个地区的沙漠治理问题。研究结果表明,提高工业生产排放技术或沙漠治理技术均能够提高均衡经济产出水平,在工业生产收益系数较高的情况下也能够提高沙漠治理投入水平,并且两种技术提高存在交互效应;只有对生产排放技术水平和沙漠治理技术水平较高的地区,延长地方政府领导任期有利于沙漠治理;实现沙漠完全治理情况下控制土地再沙化的治理投入低于控制沙漠稳定在一定规模的治理投入。     

Gowers norms and pseudorandom measures of subsets

Let $A \subset {{\Bbb Z}_N}$, and ${f_A}(s) = \left\{ {\begin{array}{*{20}{l}}{1 - \frac{{|A|}}{N},}&{{\rm{for}}\;s \in A,}\\{ - \frac{{|A|}}{N},}&{{\rm{for}}\;s \notin A.}\end{array}} \right.$ We define the pseudorandom measure of order k of the subset A as follows, P_k(A, N) = $\begin{array}{*{20}{c}}{\max }\\D\end{array}$|$\mathop \Sigma \limits_{n \in {\mathbb{Z}_N}}$f_A(n + c₁)f_A(n + c₂) … f_A(n + c_k)|, where the maximum is taken over all D = (c₁, c₂, . . . , c_k) ∈ ${\mathbb{Z}^k}$ with 0 ≤ c₁ < c₂ < … < c_k ≤ N - 1. The subset A ⊂ ${{\mathbb{Z}_N}}$ is considered as a pseudorandom subset of degree k if P_k(A, N) is “small” in terms of N. We establish a link between the Gowers norm and our pseudorandom measure, and show that “good” pseudorandom subsets must have “small” Gowers norm. We give an example to suggest that subsets with “small” Gowers norm may have large pseudorandom measure. Finally, we prove that the pseudorandom subset of degree L(k) contains an arithmetic progression of length k, where L(k) = 2·lcm(2, 4, . . . , 2|$\frac{k}{2}$|), for k ≥ 4, and lcm(a₁, a₂, . . . , a_l) denotes the least common multiple of a₁, a₂, . . . , a_l.     

电化学氢化物发生-原子吸收光谱法测定不同价态的无机砷

不同价态的无机砷在玻碳电极上具有较高的电化学氢化物发生效率,同时又存在较为明显的差异。通过选择不同的电流条件,采用电化学氢化物发生与原子吸收光谱联用技术有效地实现了无机砷的形态分析。对试验参数和干扰情况进行了研究。As(Ⅲ)和As(Ⅴ)检出限分别为0.2μg.L-1和0.4μg.L-1;对砷量为20μg.L-1的条件下作了方法的精密度试验,测定结果的相对标准偏差(n=6)对As(Ⅲ)为1.9%和对As(Ⅴ)为3.1%。应用此方法分析了人发标准物质(GBW 09101),测得总砷量与证书值相符。     

γ—Mo2N合成过程中的热变化及中间产物的研究

采用ＤＴＡ技术，通过改变升温速率研究了γ－Ｍｏ２Ｎ合成过程中的热变化，并经ＸＲＤ，ＢＥＴ及ＩＲ测试，对ＤＴＡ曲线中的谱峰进行归属，考察了中间产物，ＤＴＡ结果表明，在ＭｏＯ３和ＮＨ３程序升温反应过程中有放热峰及吸热峰出现，且随升温速率的长高，放热峰面积与吸热峰面积之比逐渐减小，结合ＸＲＤ及ＩＲ结果可知，ＤＴＡ曲线听放热峰可归属为由ＭｏＯ３变化为ＭｏＯ２的还原峰，吸热峰则归属为由ＭｏＯ２变化为Ｍｏ２Ｎ     

DFT study of the conductance of molecular wire:The effect of coupling geometry and intermolecular interaction on the transport properties

The density functional theory (DFT) combining with the non-equilibrium Green functions (NEGF) method is applied to the study of the electronic transport properties for a Di-thiol-benzene (DTB) molecule coupled to two Au(111) surfaces. The dependence of the transport properties on the bias, the coupling geometry of the molecule-electrode interface, and the intermolecular interaction are examined in detail. The results show that the existence of the hydrogen atom at the end of the DTB molecule would significantly decrease the transmission coefficients, and then the differential conductance (dI/dV). By changing the position of the DTB molecule located between two electrodes a maximum value of calculated current is observed. It is also found that the intermolecular interaction will strongly influence the transport properties of the system studied.     

Preparation of Europium Induced Conformation—specific anti—calmodulin Monoclonal Antibody

Monoclonal antibody technique was employed to detect the conformational difference of CaM induced by metal ions. A trivalent europium ion induced conformation-specific anti-calmodulin monoclonal antibody was successfully prepared with europium-saturated calmodulin as antigen.     

PHBV/HA骨修复材料的研究

利用硝酸钙与磷酸钠的水溶液制备羟基磷灰石(HA)，同时在HA生成过程中与聚羟基丁酸一戊酸酯(PHBV)复合，探索了HA增强PHBV使之适于作为骨修复材料的一种新途径。结果表明，HA的均匀分散增进了复合材料中两相问的相互结合，能明显地提高复合材料的力学性能。     

5-氨基-1H-1，2，4-三氮唑-3-硫代-2′-丙酸乙酯类Schiff碱的合成与表征

用氨基三氮唑硫代丙酸乙酯与取代苯甲醛反应，合成了6个新型的5-氨基-1H-1，2，4-三氮唑-3-硫代-2′-丙酸乙酯类Schiff碱，其结构经^1H NMR，IR，MS和元素分析表征。     

聚酯在超临界甲醇中的降解特性

研究在间歇高压反应器中聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)及聚碳酸酯(PC)在超临界甲醇中的降解反应;通过建立聚酯在超临界甲醇中的降解反应模型,探讨了聚酯在甲醇中降解的机理。结果表明:PET、PBT和PC在甲醇溶液中的降解具有共性,均可分为超临界区、非临界区和中间过渡区三个区域。在超临界区聚酯完全溶于甲醇并降解为原料单体,且对苯二甲酸二甲酯(DMT)和碳酸二甲酯(DMC)的收率均大于90%;聚酯的降解是在聚合物分子链的无规断裂和聚酯进行酯交换反应的双重作用下发生的。