Preparation and properties of polyurethane networks based on α,ω-difunctional poly(hexafluoropropylene oxide)

Poly(hexafluoropropylene oxide), poly(HFPO), networks were prepared from functional polymers by end linking via urethane groups. The prepolymers were characterized by NMR spectroscopy and GPC. The networks were characterized by determination of the number of network chains from the shear modulus, and were snown to contain both trifunctional crosslinks and difunctional links. The properties of the networks were investigated by a range of techniques. Compared with fully-fluorinated networks formed via triazine cross-links, investigated previously, the urethane-linked networks were more readily prepared but were poorer elastomers, were less thermally stable, and were less resistant to swelling by common polar solvents. © 1995 John Wiley & Sons, Inc.     

Synthesis,Luminescence and Intramolecular Energy Transfer of Binary and Ternary Rare Earth Complexes with Aromatic Carboxylic Acids and 1, 10-Phenanthroline

A series of binary and ternary rare earth complexes with para-substitued benzoic acids and 1,10-phenanthroline were synthesized. The phosphorescence spectra were measured and the lowest triplet state energies of ligands were determined, the phosphorescence lifetimes were obtained and intramolecular energy transfer mechanism between ligands was studied. The luminescence properties were also measured and were in agreement with the prediction. The energy match and intramolecular energy transfer process in these binary and ternary complexes were discussed in detail.     

Reversed-phase high-performance liquid chromatographic, gel electrophoretic and size exclusion chromatographic studies of subunit structure of arachin and its molecular species

Arachin and its molecular species (arachin I and arachin II) were separated and isolated. The number and kind of subunits of arachin, arachin I and arachin II were determined. Studies were carried out under different experimental conditions using slab gel electrophoresis, size-exclusion chromatography and reversed-phase high-performance liquid chromatography. Gel electrophoresis was done under varying concentrations of resolving gel. Tube gel as well as slab gel electrophoresis were used and continuous as well as discontinuous buffer systems were used for both types of electrophoresis. In addition, the subunits were separated by reversed-phase HPLC using a gradient program. Arachin and arachin II were found to have 12 subunits each while arachin I showed six subunits. The subunits of arachin I were allowed to reconstitute by removing SDS. Eight combinations were tried for studying the reconstitution pattern. Molecular weight and weight ratio in each case were also determined.     

Product analyses of ozone mediated nitration of benzimidazole derivatives with nitrogen dioxide: formation of 1-nitrobenzimidazoles and conversion to benzotriazoles

Several benzimidazole derivatives having electron-withdrawing or -donating substituent(s) at the benzene moiety were used as models of the imidazole moiety of purine bases and their nitration with nitrogen dioxide and ozone (so-called Kyodai nitration) were examined. Products were extracted from the reaction mixture with AcOEt and their structures were analyzed. 1-Nitrobenzimidazole derivatives and unexpected 1-nitrobenzotriazole derivatives were identified. Although the yields of 1-nitrobenzimidazole derivatives were quite low, these were all new compounds that could be obtained only by Kyodai nitration. It was speculated that benzotriazoles were formed via 1-nitrobenzimidazoles and subsequent nitration toward benzotriazoles resulted in the formation of 1-nitrobenzotriazoles.     

南瓜籽烘烤前后化学成分的分析

对烘烤前后南瓜籽中的化学成分进行分析并对比。采用同时蒸馏萃取装置萃取南瓜籽中的挥发性成分,采取超临界CO2萃取技术萃取南瓜籽油脂,并将其分为酸、碱、中性三个部分,用气相色谱-质谱联用方法分析其中化学成分并进行对比。结果表明,南瓜籽挥发性成分中含有多种醛类和酯类化合物,烘烤后产生了大量的烷基吡嗪,其在碱性部分中的相对含量比烘烤前提高14倍多,不饱和醛类化合物含量也有明显提高。南瓜籽油脂中的主要化学成分是油酸、亚油酸及其酯类。还含有生物活性功能成分如植物甾醇、角鲨烯和维生素E等。烘烤后除角鲨烯含量有所降低,维生素E、植物甾醇、亚麻酸等均有提高。     

Conformational studies of tertiary oligo-m-benzanilides and oligo-p-benzanilides in solution

A series of oligo-m- and p-benzanilides were made and their conformations in solution were studied by NMR. In most cases, conformational mixtures were observed as soon as three or more monomers were incorporated into the oligomer. Some crystal structures were obtained, which indicated that helical conformations were adopted in the solid state.     

Vibrational spectroscopic study on 2-[2-(4-dipropylamino-phenyl)-vinyl]-1,3,3-trimethyl-3H-indolium chloride

A new styryl dye were prepared, 2-[2-(4-dipropylamino-phenyl)-vinyl]-1,3,3-trimethyl-3H-indolium chloride (DPPTVI) chloride. Its infrared and Raman were measured. Quantum chemical calculations were computed for both the isolated and the solute cation. Optimized geometry, atomic net charges were calculated. The calculated vibrational frequencies were scaled to the experimental ones. Only 12 scale factors were used for the scaling of 174 vibrational modes. Based on these results, normal coordinate analysis were carried out for both the isolated and the solute cations. Infrared and Raman spectra were simulated. The results for the isolated and the solute cations were compared.     

Clinical effects of monocomponent insulin and commercial insulin preparations on insulin requiring diabetics (author's transl)

Diurnal variation of blood sugar, C-peptide immunoreactivity (CPR), free insulin and total insulin were measured in 10 insulin requiring diabetics after obtaining adequate control of diabetes with commercial lente insulin treatment. Following these tests, insulin treatment were changed to monocomponent insulin (MC-insulin) from commercial lente insulin treatment in all subjects and the same tests were performed at 7th day of MC-insulin treatment. Diurnal variations of blood sugar in both groups were not changed significantly. Also changes in CPR of both groups were nearly same magnitude and endogenous insulin secretion in these insulin treated diabetics were suggested except a case of juvenile diabetic subject. However personal variation were great in diabetics with high antibody titer, diurnal variations of total extractable insulin in both groups were quite comparable. And mean diurnal changes in free insulin were resemble to that of CPR. All of these data suggested that clinical effects of MC-insulin and commercial insulin treatment on insulin requiring diabetics were comparable except insulin antibody or proinsulinspecific antibody production.     

云南菊科中草药中铅含量特征分析

论述了云南２７种菊科中草药及其水提取物中铅含量的特征。菊科植物及水提物中铅含量的频数分布为正偏态,两者的相关系数ｒ＝０．０９,未呈现显著的线性相关。提取率较高的山紫苑、佩兰、木香铅实际含量低;铅含量高的叶下花、狭叶兔耳风、臭灵丹提取率又较低,减少了人体对Ｐｂ的过量摄入。     

膜催化研究II. 多孔无要膜的制备与表征及其反应器对甲醇脱氢反应的促进作用

采用溶胶-凝胶法制备了多孔氧化铝膜, 并通过DSC、TGA、SEM、N~2吸附和气体透过率测定等手段, 对膜的性能进行了表征。结果表明, 用这种方法制备的多孔氧化铝膜是一种均匀无裂痕和具有较窄孔径分布(约4nm)的膜材料。将此多孔氧化铝膜制成膜反应器后, 用于甲醇催化脱氢制甲醛的反应, 发现甲醇转化率比常规反应器有较大幅度的提高。同时首次尝试采用溶胶-凝胶法将催化活性组分直接负载到多孔氧化铝膜上, 从而得到了一种具有催化活性的多孔膜, 并考察了它的反应活性。文中对由这两种多孔膜及钯/陶瓷复合膜制成的反应器的特点进行了比较。     

Detection of chemical agents in the atmosphere by open-path FT-IR spectroscopy under conditions of background interference: I. High-frequency flashes

Open-path FT-IR spectra were measured while fireworks were emitting smoke and incandescent particles into the infrared beam. These conditions were designed to simulate the appearance of smoke and explosions in a battlefield. Diethyl ether was used to simulate the vapor-phase spectra of G agents such as sarin. The measured interferograms were corrected by a high-pass filter and were rejected when interfering features were of such high frequency that they could not be removed by application of this filter. The concentration of diethyl ether was calculated correctly by partial least squares regression in the absence of fireworks but significant errors were encountered when the spectra of the oxide particles were not included in the calibration set. Target factor analysis allowed the presence of the analyte to be detected even when the incandescent particles were present in the beam.     

IClO2异构化反应机理及电子密度拓扑研究

利用密度泛函理论方法研究了IClO2异构化反应机理. 优化得到了七种异构体, 其中OIClO和IClOO还未见报道, 对各异构体的热力学稳定性进行了比较. 找到了异构化过程的过渡态, 并通过内禀反应坐标(IRC)计算确认了各个异构体之间的相互转化关系. 从量子拓扑学的角度, 对典型异构化反应通道IRC途径上的各点进行了电子密度拓扑分析, 讨论了反应过程中化学键的断裂、生成以及化学键的变化规律, 找到了反应途径上的能量过渡态(ETS)和结构过渡态(STS).     

From Amino Acids to High‐Energy Dense Oxidizers: Polynitro Materials Derived from β‐Alanine and L‐Aspartic Acid

New oxygen‐rich compounds starting from the amino acids β‐alanine and L ‐aspartic acid were synthesized and comprehensively analyzed including multinuclear NMR spectroscopy and vibrational spectroscopy. Thermal stabilities were measured and the behavior towards external stimuli like friction or impact were determined. Detonation and combustion parameters were predicted by using the EXPLO5 V6.02 code and were compared with common explosives. In addition, crystal structures were obtained for two compounds.     

PET导电纤维的制取及研究

以过氧化二苯甲酰为引发剂,使丙烯睛在涤沦(PET)纤维上接枝共聚。接枝纤维在含铜化合物,含硫还原剂溶液中反应,制备PET导电纤维。讨论了影响接枝共聚的各种因素,选择出最佳聚合条件。对该纤维的导电成份和结构以及性能进行了研究。     

Determination of Petroleum Products in Water by Measuring Integral Intensities of νCH Absorption Bands with a Fourier-Transform IR Spectrophotometric Complex

A new method was proposed on the basis of computer-assisted IR spectrometry for the separate determination of aliphatic (Alk) and aromatic (Ar) petroleum products in water samples. The integral intensities of absorption bands were measured with a Fourier-transform IR spectrophotometric complex. A series of individual hydrocarbons and their mixtures was studied, and real water samples were analyzed. The conditions for recording and computer processing of IR spectra were selected. Based on the published data and experimental data obtained using reference samples, optimal regions for recording IR spectra were characterized, and integration intervals were found for characteristic band areas of aromatic and aliphatic hydrocarbons. Regression equations were derived on an assumption that the system is binary. Working coefficients in the Bouguer–Lambert–Beer's law were found. Interval estimates of errors in the proposed method were calculated. Practical recommendations were given.     

Structural features of benzylic carbanions. A theoretical study

Benzylic anions were studied with the semiempirical MNDO molecular orbital method. Structural changes were analyzed as metal counterions and solvents were allowed to interact with the benzylic carbon. Generally, benzylic carbanions were found to be trigonal planar but became pyramidal or bent when metals were included in the calculation.     

某些内-双环[2.2.2]辛烯(或辛烷)基-2-甲醛缩醛的合成及香气

某些缩醛的香气比其母体醛优雅,且性质稳定,成为近年来调香中使用的一类新化合物。因此,我们继合成了一系列双环[2.2.2]辛     

Analysis of endosulfan isomers and endosulfan sulfate in air and tomato leaves by gas chromatography with electron-capture detection and confirmation by gas chromatography-mass spectrometry

Rapid analytical methods for the determination of endosulfan isomers and endosulfan-sulfate in air and plant samples were developed. The insecticides were trapped from air using a column containing Florisil and extracted with a low volume of ethyl acetate, assisted by sonication. Pesticide residues were determined by gas chromatography with electron-capture detection using a nonpolar capillary column. Residue identities were confirmed by gas chromatography coupled with mass spectrometry. Recoveries of these compounds from air samples were always higher than 78% with an RSD lower than 11% and the detection limits obtained were at least 0.3 ng/l air. Leaf samples were homogenised with ethyl acetate and extracts cleaned-up on an aluminium oxide column. Pesticides were eluted with a hexane-ethyl acetate (80:20, v/v) mixture. Recoveries obtained from plant samples were higher than 78% with an RSD lower than 14% and detection limits in leaves were 0.02 microg/g for each pesticide. These methods were applied to study the volatilisation of endosulfan from tomato leaves under laboratory conditions. A volatilisation rate near 1% of the initial amount of endosulfan per hour was obtained during the first 24 h at room temperature.     

Manipulation of protein fingerprints during on-column fluorescent labeling: protein fingerprinting of six Staphylococcus species by capillary electrophoresis

Bacterial proteomes were analyzed by use of electrophoretically mediated microanalysis (EMMA) and field-enhanced stacking. A water-soluble protein fraction was injected onto a capillary. Next, a fluorogenic reagent was injected and allowed to react with the protein mixture, producing fluorescent products that were separated by submicellar capillary electrophoresis and detected by laser-induced fluorescence. By use of a low-ionic strength sample buffer and a brief electrophoretic step, slow moving anionic proteins were stacked at the reagent-sample interface and were preferentially labeled. By reversing the order of sample injection and labeling reagent, fast moving cationic proteins were preferentially labeled. By adjustment of the sample buffer pH, proteins with different isoelectric points were selectively labeled. Electrophoresis fingerprints were generated for the water-soluble protein fraction from six Staphylococcus species. The protein patterns produced were species-specific and were used to construct a phylogenetic tree.     

Effect of Alkyl Chain Length of N-Alkyl-N′-(2-benzylphenyl)ureas on Gelation

Urea derivatives that were substituted with a 2-benzylphenyl group and an alkyl group functioned as low molecular weight gelators for various organic solvents and ionic liquids. Urea derivatives with long alkyl chains were effective for the gelation of polar solvents. However, they were not suitable for the gelation of non-polar solvents, whereas urea derivatives with short alkyl chains were effective. Ionic liquids were similar to polar solvents in that urea derivatives with long alkyl chains were the most effective gelators. The physical properties of the formed supramolecular gels were analyzed by dynamic viscoelasticity measurements using a rheometer.