动态法测定耐硫甲烷化催化剂的有效导热系数

本文采用动态法原理，用单丝直径为０．２ｍｍ的铜－录铜热偶作为测温元件，在３１３－５３３Ｋ温度区间，测定了耐硫甲烷化催化剂的有地热系数。用石蜡和锡作为参比物，对所用仪器及实验方法进行了可靠性检验。实验表明，动态法是测定多孔硫化物催化剂导热系数的有效方法。其精度符合工程要求，亦能用于其它材料导热系数的测定。对所测数据用单纯形方法优化拟合，得到大于３５３Ｋ范围内的有效导热系数的经验公式。     

Enzymatic reaction of the immobilized enzyme on porous silicon studied by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry

Desorption/ionization on silicon mass spectrometry (DIOS-MS) is a matrix-free technique that allows for the direct desorption/ionization of low-molecular-weight compounds with little or no fragmentation of analytes. This technique has a relatively high tolerance for contaminants commonly found in biological samples. DIOS-MS has been applied to determine the activity of immobilized enzymes on the porous silicon surface. Enzyme activities were also monitored with the addition of a competitive inhibitor in the substrate solution. It is demonstrated that this method can be applied to the screening of enzyme inhibitors. Furthermore, a method for peptide mapping analysis by in situ digestion of proteins on the porous silicon surface modified by trypsin, combined with matrix-assisted laser desorption/ionization-time of flight-MS has been developed.     

4-乙烯基吡啶-镍(钴)及丙烯酰胺-镍(钴)的制备、结构、聚合及聚合物的催化性能

制备了4-乙烯基吡啶-镍(钴)和丙烯酰胺-镍(钴)络合物并研究了它们的结构。在自由基引发剂的作用下,4-乙烯基吡啶-镍可进行溶液聚合,也可与苯乙烯共聚合,测定了单体的竞聚率。所得的聚(4-乙烯基吡啶-镍)及聚(4-乙烯基吡啶-钴)以NaBH_4还原后可作为一些有机化合物的加氢催化剂。由IR及XPS分析说明在丙烯酰胺-镍络合物中,与镍离子发生了络合作用的是羧基上的氧原子。     

铈、镨二乙基磷酸盐的晶体结构

合成了Ce[PO_2(OC_2H_5)_2]_3和Pr[PO_2(OC_2H_5)_2]_3(简称Ce(DEP)_3和Pr(Pr(DEP)_3)。用四圆衍射仪测定了其晶体结构。它们均属三斜晶系,空间群P1。晶胞参数,对Ce(DEP)_3:α=10.324(4)A,b=12.861(4)A,c=13.998(5)A,x=106.49(3)°,β=112.83(4)° γ=115.61(3)°,V=1296(1)A~3,Z=2;对Pr(DEP)_3:α=10.27(1)A,b=11.81(1)A,c=12.51(1)A,x=109.93(9)°,β=111.9(9)°,γ=93.0(1)°,V=1293(3)A~3,Z=2。用Patterson法并经分块全矩阵最小二乘法修正,最后的R值,Ce的为0.1071,Pr的为0.1066。结构分析指出,两种配合物结构类似,Ce和Pr原子均由二乙基磷酸根的六个氧原子配位形成八面体构型。     

Stimulated emissions in aligned CdS nanowires at room temperature

Aligned CdS nanowires (NWs) were obtained through a simple thermal evaporation process with highly active CdS nanoparticles as the evaporation source. These NWs show prominent optical waveguides behavior under a continuous-wave (CW) laser excitation. Excitation intensity-dependent photoluminescence (PL) measurements show that these NWs exhibited both broad and supernarrow stimulated emission (lasing) under intense pulse optical excitation at room temperature. Raman scattering and time-resolved PL measurements were used to investigate the optical properties. The results indicated that the stimulated emission in these NWs involves the electron-hole plasma (EHP) and Farby-Perot (F-P) optical resonant processes at room temperature.     

An ab initio study on luminescent properties and aurophilic attraction of binuclear gold(I) complexes with phosphinothioether ligands

Electronic structures and spectroscopic properties of the binuclear head-to-tail [Au(2)(PH(2)CH(2)SH)(2)](2+) (1) complex were investigated by ab initio calculations. The solvent effect of the complex in the acetonitrile solution was taken into account by the weakly solvated [Au(2)(PH(2)CH(2)SH)(2)](2+).(MeCN)(2) (2) moiety in the calculations. The ground-state geometries of 1 and 2 were fully optimized by the MP2 method, while their excited-state structures were optimized by the CIS method. Aurophilic attraction apparently exists between the two Au(I) atoms in the ground state and is strongly enhanced in the excited state. A high-energy phosphorescent emission was calculated at 337 nm for 1 in the absence of the interactions with solvent molecules and/or counteranion in solid state; however the lowest-energy emission of 2 was obtained at 614 nm with the nature of (3)A(u)(s(sigma)) --> (1)A(g)(d(sigma)) (metal-centered, MC) transition. The coordination of acetonitrile to the gold atom in solution results in a dramatic red shift of emission wavelength. The investigations on the head-to-tail [Au(2)(PH(2)CH(2)SCH(3))(2)](2+) (5) and [Au(2)(PH(2)CH(2)SCH(3))(2)](2+).(MeCN)(2) (6) moieties indicate that the CH(3) substituent on the S atom causes blue shifts of emission wavelength for 5 and 6 with respect to 1 and 2. By comparison between Au(I) thioether 1 and head-to-tail Au(I) thiolate [Au(2)(PH(2)CH(2)S)(2)] (7), it is concluded that the S-->Au dative bonding results in evidently different transition characteristics from the S-Au covalent bonding in the Au(I) thioether/thiolate complexes.     

2020 Roadmap on two-dimensional nanomaterials for environmental catalysis

This roadmap demonstrates a series of two-dimensional nanomaterials, such as graphene, black phosphorus, oxides, layered double hydroxides, chalcogenides, bismuth-based layered compounds, MXenes, metal organic frameworks, covalent organic frameworks, and others, for environmental catalysis.     

Determination of minor conformational changes of a doxorubicin-peptide conjugate under chromatographic conditions

Thermodynamic analysis of the reversed-phase retention behavior of a doxorubicin-peptide conjugate demonstrated that the degree of non-linearity observed in Van't Hoff plots was impacted by mobile phase acetonitrile content over the 25-38% acetonitrile (v/v) range tested. Small decreases in the non-polar surface area of the doxorubicin-peptide conjugate as a function of temperature were estimated from these data using linear solvent strength relationships, suggesting that the retention behavior may be the result of minor analyte conformational changes during the chromatographic experiment. This hypothesis was supported via circular dichroism (CD), Raman and 1H NMR spectroscopic studies of the doxorubicin-peptide conjugate in selected chromatographic mobile phase compositions. The CD and Raman data indicated small changes to the apparent analyte microenvironment as a function of temperature and bulk solvent environment, while 1H NMR studies specifically demonstrated the environmental sensitivity of protons on three non-polar peptide residues and the proximal aromatic region of the analyte. Together, these data suggest that minor changes to the conformational order of the essentially random structure of the doxorubicin-peptide conjugate are sufficient to impact chromatographic performance.     

高分子-AlCuCl4膜及其气体透过行为探讨

把对一氧化碳具有选择吸附功能的液体吸附剂(AlCuCl_4-甲苯溶液和AlCuCl_4-Pst-甲苯溶液)引入到高分子(EC、Pst、ABS、CA)膜材料中,制成固体膜,考察了膜的气体透过性能,同时初步得出结果认为,膜中的AlCuCl_4以电荷转移配合物形式与高分子配位结合.     

Influence of inorganic mobile phase additives on the retention, efficiency and peak symmetry of protonated basic compounds in reversed-phase liquid chromatography

Inorganic eluent additives affect the retention of protonated basic analytes in reversed-phase HPLC. This influence is attributed to the disruption of the analyte solvation-desolvation equilibria in the mobile phase, also known as "chaotropic effect". With an increase of counteranion concentration analyte retention increases with concomitant decrease in the tailing factor. Different inorganic counteranions at equimolar concentrations affect protonated basic analyte retention and peak symmetry to varying degrees. The effect of the concentrations of four different inorganic mobile phase additives (KPF6, NaClO4, NaBF4, NaH2PO4) on the analyte retention, peak symmetry, and efficiency on a C8-bonded silica column has been studied. The analytes used in this study included phenols, toluene, benzyl amines, beta-blockers and ophthalmic drugs. The following trend in increase of basic analyte retention factor and decrease of tailing factor was found: PF6- > ClO4- approximately BF4- > H2PO4-. With the increase of the counteranion concentration greater analyte loading could be achieved and consequently an increase in the apparent efficiency was observed until the maximum plate number for the column was achieved. At the highest concentration of counteranions, the peak efficiency for most of the basic compounds studied was similar to that of the neutral markers. In contrast, the neutral markers, such as phenols, showed no significant changes in retention, efficiency or loading capacity as counteranion concentration was increased.