Theoretical studies on the influence of metallic cations on ring opening of propylene oxide catalyzed by metal-salen complexes

We studied the ring opening of propylene oxide (PO) by salen-M coordinated OH⁻ group [M = Al(III), Sc(III), Cr(III), Mn(III), Fe(III), Co(II), Co(III), Ni(II), Cu(II), Zn(II), Ru(III) and Rh(III)]. The results show that the ring-opening energy barriers for M(II) complexes are much lower than those with M(III) complexes in the gas phase, and the barriers correlate linearly with the negative charges on the OH⁻ group and the Fukui function condensed on the OH⁻ group. The nucleophilicity ordering in the gas phase can be rationalized by the ratio of formal positive charges/radius of M cations. Solvent effect greatly increases the barriers of M(II) complexes but slightly changes the results of M(III) ones, making the barriers similar. Analysis indicates that the reaction heats are linearly proportional to the reverse reaction barriers. The relationships established here can be used to estimate the ring-opening barriers and to screen epoxide ring-opening catalysts.     

Quantum Cosmology in CGBD Theory

We apply the theory developed in quantum cosmology to a model of charged generalized Brans–Dicke gravity. This is a quantum model of gravitation interacting with a charged Brans–Dicke type scalar field which is considered in the Pauli frame. The Wheeler–DeWitt equation describing the evolution of the quantum Universe is solved in the semiclassical approximation by applying the WKB approximation. The wave function of the Universe is also obtained by applying both the Vilenkin-like and the Hartle–Hawking-like boundary conditions. We then make predictions from the wave functions and infer that the Vilenkin's boundary condition is more reasonable in the Brans–Dicke gravity models leading a large vacuum energy density at the beginning of the inflation.     

Unlabeled Fluoroimmunoassay with a Europium Chelate

Unlabeled fluoroimmunoassay with a europium chelate is described. The recommended method is simple because the complicated labeling process is omitted. The recovery of some samples ranges from 91 to 111%. The relative standard deviation of the method is less than 10%. The detection limit is about 10⁻¹⁰mol liter⁻¹antigen.     

Mechanistic Simulation Studies on Viscous-Elastic Polymer Flooding in Petroleum Reservoirs

Based on the theory and application developments of polymer flooding on enhancing oil recovery, an improved mathematical model has been developed to simulate the mechanism of viscous-elastic polymer flooding. IMPES method has been presented to solve the polymer flooding model considering the viscosifying effect of elasticity, the effect of decreasing residual oil and the degradation of polymer molecules. The validation of the model is approved by an experiment. A simulation example was carried out using the developed numerical simulator. The enhanced oil recovery mechanism was discussed for viscous-elastic polymer flooding, and corresponding influencing factors were also studied.     

在线质谱仪检测植物排放的挥发性有机物

利用在线检测质谱仪(SPIMS-1000)分别对高温烘烤、长时间密封保存、机械损伤等处理过的松科松属马尾松(Pinus Massoniana L.)样品排放的挥发性有机物(VOCs)与新鲜样品进行对比检测。SPIMS-1000在线检测质谱仪能够检测出植物排放的异戊二烯(m/z 68)和单萜(m/z 136),及其它一些特异性组分,如(Z)-3-己烯醛(m/z 98)等。利用在线检测质谱仪实现敞开环境中原位植物排放气体的检测。实验表明,在线检测质谱仪被广泛应用于环境中VOCs的实时、在线、定性快速检测。     

5,3'''',5''''-三磺酸基-2,3,4,4''''-四羟基脱氧安息香三钠盐的合成、晶体结构及性质研究

合成了水溶性很好的5,3',5'-三磺酸基-2,3,4,4'-四羟基脱氧安息香三钠盐(TTDB), 采用IR、 UV、 1H NMR和元素分析对其结构进行了表征, 并利用X射线单晶衍射仪测定了该化合物的晶体结构. 使用荧光光谱法检测了化合物对羟基自由基的清除作用. 用循环伏安法探讨了化合物的电化学性质. 实验结果表明, 5,3',5'-三磺酸基-2,3,4,4'-四羟基脱氧安息香三钠盐[C14H17Na3O18S3]属于单斜晶系, 空间群C2/c, a=1.422 3(4) nm, b=2.432 7(8) nm, c=1.359 6(4) nm, α=90°, β=113.044(5)°, γ=90°, Z=8, V=4.329(2) nm3, Dc=1.925 Mg/m3, F(000)=2 568, Mr=627.43, R1=0.095 0, wR2=0.264 8. TTDB的抗羟基自由基的氧化作用优于其相应的脱氧安息香THDB, 前者清除羟基自由基的半数有效浓度(EC50)为47.3 μmol/L, 而后者的EC50则为53.1 μmol/L. 电化学研究结果表明, THDB和TTDB的氧化还原过程有所差异, 前者负扫时在-1.016和-1.228 V处出现两个还原峰, 正扫时在0.219 V处出现一个氧化峰, 但后者负扫时仅在-0.999 V出现一个还原峰, 正扫时在0.193 V出现一个氧化峰.     

巯基卟啉自组装膜的制备及应用研究进展

详细介绍了巯基卟啉自组装膜的几种制备方法,评述了不同制备方法的优缺点;对卟啉自组装膜在电荷转移、分子氧电催化、分子光电器件等领域的研究进展进行了评述,引用文献54篇。     

K3PO4 promoted dipolar [3+3] cyclization: Direct synthesis of pyrazino[2,1-a]isoquinoline derivatives

A K₃PO₄ promoted dipolar [3+3] cyclization of dihydroisoquinoline imines and arylacyl bromides has been developed. This process realized the direct synthesis of pyrazino[2,1-a]isoquinoline derivatives in 44–69% yields. A head to tail dimerization was proposed as key step for this procedure.     

非高斯噪声驱动下一维双稳系统的逻辑操作

本文以成功率作为逻辑随机共振的测度, 主要研究了非高斯噪声激励下一维双稳系统的逻辑随机共振现象, 并用平均首次通过时间的方法对此现象的机理进行了解释. 研究结果表明: 只有在适当的噪声强度带或关联时间带上, 成功率才会达到共振峰值. 通过对系统参数进行优化, 提高了系统实现逻辑操作的可靠性. 关键词： 逻辑随机共振 一维双稳系统 非高斯噪声 平均首次通过时间     

B-N共掺杂改善p型ZnO的理论分析

采用基于密度泛函理论的第一性原理赝势法对B缺陷在ZnO中的存在形式进行了理论分析,对B-N共掺杂ZnO体系的晶格结构、杂质形成能、杂质态密度及电子结构进行了系统的研究.研究表明,B缺陷在掺杂体系中主要以BZn的形式存在,这种结构会引起相应的晶格收缩;研究发现与以往的N掺杂相比,共掺结构具有更低的杂质形成能和更高的化学稳定性,因此更加适合掺杂.此外,共掺能够形成更低的受主能级,因而减小了受主的杂质电离能,提高了受主态密度;研究显示共掺结构下的杂质N原子与体相Zn原子之间的键合能力提高,受主原子得电子的能力增强,因此B-N共掺有望成为一种更为有效的p型掺杂手段.