Short-time vibrational dynamics of acetylene versus its isotopic variants

The short-time intramolecular dynamics of highly vibrationally excited HCCD and DCCD, as determined by classical trajectories, have qualitative features distinct from HCCH and from one another. The possible differences are also considered from the point of view of the symmetries of the normal modes. The short-time evolution will be reflected in the coarse-grained frequency spectrum and could be detectable via stimulation emission pumping.     

对甲苯磺酰谷氨酸桥联的一维双链锰配合物的合成、表征与晶体结构

A one-dimensional double-chain coordination polymer [Mn(phen)(tsgluo)] was synthesized in a mixed solution and its crystal structure was determined by X-ray diffraction method. It crystallizes in orthorhombic system with space group P2₁2₁2₁. The crystal data are: a=0.530 78(17) nm, b=1.723 9(5) nm, c=2.456 9(8) nm, Z=4, μ=0.729 mm^-1, D_c=1.579 g·cm^-3, V=2.248 1(12) nm³, R₁=0.033 1, ωR₂=0.078 9. In the title complex, each Mn(Ⅱ) ion presents a octahedral geometry with the coordination of two nitrogen atoms from 1,10-phenanthroline and four oxygen atoms from three different tsgluo^2- ligands. The γ-carboxyl coordinates to Mn(Ⅱ) in the mode of bidentate chelate, while the α-carboxyl coordinates in a bidentate bridging mode. CCDC: 253910.     

晶态氮化碳薄膜的低温合成

The synthesis of carbon nitride films at low temperature has been investigated using pulsed arc discharge from methanol solution with nitrogen atmosphere. Raman spectra and X-ray diffraction (XRD) analysis suggest that crystalline carbon nitride films may be prepared at low substrate temperature (220 ℃). At same time, the substrate temperature has a significantly effect on the nitrogen content and structure of the films. Increasing substrate temperature (300 ℃) would decrease the content of nitrogen in the films and result in a formation of carbon films.     

亲水性交联聚合物载体的合成表征及其固定化α-淀粉酶

选用丙烯酰胺(AM)、N-羟基琥珀酰亚胺为单体(NHS),以N,N/-亚甲基双丙烯酰胺(MBAA)为交联剂,以乙醇水溶液为制孔剂条件下进行反相悬浮聚合,得到珠状共聚物载体,该载体是一种新的酶载体形式,在国内外的相关文献中均未见报道.用红外光谱、扫描电子显微镜测定其结构和表观活性.结果表明,在固定单体配比[W(AM)/W(NHS)=10∶1]和致孔剂用量的情况下,测得交联剂用量为4%时,交联聚合物载体的溶胀性最好(287.5%);交联剂用量为5%时,交联聚合物载体固定化α-淀粉酶表现出高的表观活性(522.53U/g).测得固定化酶载体表现出良好的操作稳定性.比较固定化酶和游离态酶的最适反应温度发现,固定化酶的最适反应温度(70℃)比游离态酶高20℃;固定化酶的最适反应pH值范围较游离态酶广.     

二氯亚甲基环己烷的卤化反应和2-取代二氯亚甲基环己烷的构象

多卤代烃在有机反应机理和结构研究中有着重要意义,作为一个有用的合成中间体,其制备也受到人们重视。我们在此报道二氯亚甲基环已烷(1)与氯及溴的反应和其它有关反应的实验结果。 1 于氯作用,主要得到加成产物1—氯—1—     

双环[2，2，1]庚-5-烯-2-甲酰基芳香醛腙的合成和生物活性

合成了七个未见文献报道的双环[2，2，1]庚-5-烯-2-甲酰基芳香醛腙席夫碱 类化合物。用核磁共振氢谱、红外光谱和元素分析对新化合物进行了表征，考察了 它们的生物活性。结果表明某些化合物具有除草作用、抗菌作用和植物生长调节作 用。     

批量离子交换层析和凝胶过滤层析在类人胶原蛋白I纯化中的应用

研究了利用批量离子交换层析与凝胶过滤层析相结合的方法纯化类人胶原蛋白I的最佳条件。分别考察了不同离子交换树脂、缓冲溶液pH、离子强度、进料蛋白浓度对批量离子交换的影响,以及不同凝胶过滤介质对凝胶过滤层析的影响。结果表明,采用阴离子交换树脂DEAE52吸附杂蛋白,缓冲液pH为7.0,NaCl浓度为0.2mol/L,进料蛋白浓度为40mg/mL,并采用凝胶过滤介质SephadexG-100进一步纯化后,类人胶原蛋白I的纯度可达到98.2%,总纯化倍数为3.1,总回收率为80.6%。SDS-PAGE分子量分析和N末端氨基酸序列分析均表明纯化后的类人胶原蛋白I与基因设计一致。     

相转移催化应用于催化裂化汽油氧化脱硫的研究

随着人们环境保护意识的增强及原油硫含量的增大, 生产满足环境保护要求的清洁燃料是全球炼油工业的发展趋势, 燃料油脱硫显得越来越重要. 在众多的脱硫方法中, 选择性氧化脱硫技术以其工艺条件温和, 脱硫效果明显等特点, 受到了炼油行业的极大关注[1~3], 但脱硫率偏低(30％), 其关键是水相氧化剂与含硫化合物的有效混合. 本文将相转移催化应用于催化裂化(FCC)汽油的氧化脱硫中, 并对脱硫的工艺和机理进行了研究.     

Ab initio excited-state dynamics of the photoactive yellow protein chromophore

The photoisomerization mechanism of the neutral form of the photoactive yellow protein (PYP) chromophore is investigated using ab initio quantum chemistry and first-principles nonadiabatic molecular dynamics (ab initio multiple spawning or AIMS). We identify the nature of the two lowest-lying excited states, characterize the short-time behavior of molecules excited directly to S2, and explain the origin of the experimentally observed wavelength-dependent photoisomerization quantum yield.     

The dependence of the branching ratio in the F+HD reaction on the initial rotational state of HD

Both classical trajectory and quantal scattering calculations indicate that the branching ratio in the F+HD reaction varies considerably with the initial rotational state of HD. Information theory argues that this variation must be reflected in the distribution of the reaction products. Hence, given the (normalized) product distribution for each reaction path one should be able to predict the dependence of the branching ratio on the state of the reagents. The trajectory computations of Muckerman are used to illustrate the procedure. First the dynamic constraint is identified and then the reaction probability matrix is constructed. The determination (“synthesis”) of the matrix, in terms of the given constraint invokes information theory and, in particular, the procedure of maximising the entropy. The branching ratio is readily computed from the elements of the probability matrix. Very good agreement is obtained between the trajectory-computed and the synthetic branching ratio for all initial rotational states of HD.The F+HD reaction has three possible final arrangement channels (one nonreactive and two reactive ones) and is used to illustrate the structure of the reaction probability matrix and the associated entropy measures.