合成甲醇的催化剂Rh-ZnO/MWNTs的研究

研究新型的由多壁碳纳米管(MWNTs)负载的， ZnO助催的铑基甲醇合成催化剂. 当铑含量达到4％(w)时，催化剂具有较高的比表面积(99.6 m2•g－1), 催化剂的反应活化能为68.8 kJ•mol－1.在563 K, 1 MPa下，催化剂的最高催化活性和甲醇选择性分别为411.4 mg/gcat.•h和96.7％. TEM、TPR和TPD等表征结果显示，碳纳米管能增加Rh在催化剂表面的分散度，提高催化剂的还原温度并能增加氢物种的吸附量，这些结果将有助于更好地了解催化剂中各组分间的协同作用和催化活性中心本质.     

Pharmacokinetic detection of penicillin excreted in urine using a totally internally reflected resonance light scattering technique with cetyltrimethylammonium bromide

A quantitative analysis method for penicillins including ampicillin (AmP), benzyl penicillin (BP), oxacillin (OA) and amoxycillin (AmO) is proposed that makes use of the totally internally reflected resonance light scattering (TIR-RLS) signal from the penicillin at the H₂O/CCl₄ interface in the presence of cetyltrimethylammonium bromide (CTMAB), and enables the pharmacokinetics of penicillin taken orally and excreted through urine to be monitored. Penicillin is coadsorbed with CTMAB at the H₂O/CCl₄ interface in neutral solution, resulting in the formation of ion associates that display greatly enhanced TIR-RLS signals (maximum at 368–372 nm). This enhanced TIR-RLS intensity was found to be proportional to the penicillin concentration over the range 0.2×10^–6 to 2.2×10^–6 mol L^–1, with limits of determination (3) of 5.0×10^–8 to 7.0×10^–8 mol L^–1. Pharmacokinetics studies performed using the present method show that the excretion of orally-taken ampicillin through urine has a half-time of 1.05 h and an excremental quantum over 8 h of 49.3%, respectively.     

在Mo-Bi-Ce/SiO2催化剂上甲醇氧化制甲醛的Redox机理及其动力学

用外循环无梯度反应器研究了甲醇氧化制甲醛的动力学。动力学实验结果用二步骤Redox模型描述。动力学方程中的参数用线性最小二乘法估计。甲醇的反应级数m和氧的反应级数n与温度有关, m与n的和接近于1, 反应级数的变化可用Redox机理动力学解释。不同处理催化剂的XPS分析结果证实, 反应按Redox机理进行。     

Steroidal saponins from rhizomes of Tupistra wattii Hook. f

Chemical examination of the fresh rhizomes of Tupistra wattii HOOK. f. led to the isolation of three new steroidal saponins, wattoside G (1), H (2), and I (3), together with one known steroidal saponin, (25S)-1beta,3beta,4beta-trihydroxyspirotan-5beta-yl-O-beta-D-glucopyranoside (4). The structures of 1-3 were established to be (25R)-1beta,2beta,3beta,5beta-tetrahydroxyspirostan-4beta-yl-O-beta-D-xylopyranoside (1), (24S,25S)-24-[(beta-D-glucopyranosyl)oxy]-1beta,2beta,3beta,4beta,5beta,7beta-hexahydroxyspirostan-6-one (2), and (24S,25S)-1beta,3beta-dihydroxy-5beta-spirostan-24-yl-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (3) on the basis of detailed analyses of physical, chemical, and spectral data. The isolated compounds were evaluated for cytotoxic activity against the cancer cell line K562 in vitro.     

部份互溶体系4-甲基-2-戊醇和水的过量焓研究

使用LKB-2107型流动式微量量热计测定了4-甲基-2-戊醇和水这一部份互溶体系在293.15 K、298.15 K和303.15 K的常压过量焓。测量结果用Redlich-Kister方程作了关联。另外,还用该体系富醇区的过量焓数据拟合NRTL模型的参数与温度关系,推算较高温度下该体系的常压汽液平衡(VLE)组成及泡点。推算值与文献值是接近的。实验试剂4-甲基-2-戊醇由粗品经三次蒸馏提纯,沸点为404.95 K,折光率n_D~(20)1.4113,密度d~(20)0.8067 g cm~(-3),与文献值一致。无水乙醇、尿素均为分析纯。液体试剂在使用前均     

Simultaneous determination of pantoprazole and its two metabolites in dog plasma by HPLC

A simple and sensitive high-performance liquid chromatography (HPLC) method is developed and validated for simultaneous determination of pantoprazole and its two metabolites (pantoprazole sulfone and pantoprazole thioether) in dog plasma and applied to a pharmacokinetic study in Beagle dogs. Following a protein precipitation procedure, the samples are separated using reversed-phase HPLC (C18) by a gradient of acetonitrile and ammonium acetate (pH 6.0) at a flow rate of 1.0 mL/min and quantitated using UV detection at 290 nm. Omeprazole is selected as the internal standard. The method has a lower limit of quantitation of 0.025 microg/mL for pantoprazole and its two metabolites, using 0.1-mL aliquots of plasma. The linear calibration curves are obtained in the concentration range of 0.025-10.0 microg/mL for three analytes. The intra- and interrun precision (relative standard deviation), calculated from quality control (QC) samples, is less than 13% for three analytes. The accuracy determined from QC samples is between -6.4% and 12%.     

Fluorescence observations on complex formation between linear and hyperbranched polyelectrolytes in dilute aqueous solutions

The complexation between poly(ethylene imine) (PEI) and poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) or AMPS copolymers was investigated with the relative excimer emission intensity I_E/I_M of a cationic probe 1-pyrenemethylamine hydrochloride (PyMeA · HCl), fluorescence nonradiative energy transfer (NRET) I_Py/I_Np of naphthalene to pyrene labels, the fluorescence anisotropy r and I_E/I_M of pyrene labels. PEI was a hyperbranched weak polycation in acid solution, which formed complex with anionic polyelectrolytes due to the electrostatic attraction. The I_E/I_M of PyMeA · HCl probe decreased to zero, the intra-, intermolecular NRET I_Py/I_Np and I_E/I_M of pyrene labels on the AMPS copolymers reached their maxima when χ was increased from 0 to 2.4, which was defined as the mole ratio of the amino group in PEI to the AMPS group in the polyanion. These facts indicated the formation of nonstoichiometric complex of the oppositely charged polyelectrolytes when χ = 2.4 at the concentration much lower than their overlap concentrations. The intermolecular aggregate appeared as indicated by an increase in the intermolecular I_Py/I_Np and r with χ up to 2.4 due to neutralizing and hydrophobizing the polyelectrolytes and the bridging effect of the PEI chain bound on different polyanion chains. At high pH, PEI became a neutral polymer and did not bind with the AMPS anion to form the complex as illustrated by the constant value of r for the pyrene labels attached to the AMPS polyanion as that without addition of PEI. The amino group in PEI quenched pyrene and naphthalene emission, resulting a decrease in both I_Np and I_Py.     

高能闪光照相中影响光程确定的几个因素

 利用闪光照相基本原理和成像原理，在直接记录法和转换屏记录法的情况下，研究了闪光照相中影响X射线在材料中光程确定的主要因素。结果表明，影响光程确定的几个因素是：散射效应、光源角分布效应、立体角效应和能谱效应。对于高能闪光照相，散射效应是影响光程确定的最主要因素，散射的存在使光程的测量值比实际值降低20%～40%。因此必须在做CT之前，对散射的影响进行修正。     

FTO客体3m闪光照相的Monte Carlo研究

 研究了客体模型FTO的闪光照相系统X光输运过程，给出了直穿照射量、散射照射量、直散比、直穿照射量能谱、散射照射量能谱、直穿X光通量能谱和散射X光通量能谱在记录平面的空间分布。结果表明：后锥是照射量散射成分的主要来源，后锥照射量占总散射量97%；后锥也是造成散射的空间分布不均匀的主要器件，这一不均匀性高达58%。照相系统的最小直散比非常小，表明锥造成的散射已经严重地淹没了直穿（轫致辐射）信号。计算中使用高空间分辨率记录法进行分点，合成图像对吸收系数的复原结果与国外报道的结果相符。     

神光-Ⅱ装置三倍频实验中靶场单元技术的改进

 主要介绍为了满足神光-Ⅱ高功率激光装置三倍频光（351nm，3ω）的物理实验要求，靶场三倍频模拟光源和瞄准监视系统两个主要单元技术的改进，即三倍频模拟光源由基频光（1 053nm，3ω）通过腔外的KTP+BBO晶体倍频获得，再经八路分光系统和主激光耦合；瞄准监视系统由透射式光学系统改进为反射式光学系统，避免原系统存在较大的色差，提高瞄准精度。