Methods of calculations of the energy of chemical bonds

Mean bond energies, bond dissociation energies, and other characteristics were considered for certain classes of organic (and other) compounds. The state of numerical data was discussed, and these data were ordered in series of related molecules. A methodology for calculating bond energies was developed. Numerical calculations were performed. Certain rules were considered.     

Determination of the additive physical properties of the components of complex mixtures

Summary The density, refractive index and absorptivities at chosen wave numbers were determined for all the components of three-component mixtures. The mixtures were treated of three-component mixtures. The mixtures were treated as being of unknown qualitative and quantitative composition. The quantitative gas chromatographic analysis by means of the method of linear relationship was carried out and the values of the physical properties of complex mixtures were measured. The corresponding properties of acetone, benzene and toluene were evaluated from the set of appropriate equations.     

Kinetics of combustion of oil shale with polystyrene

The combustion kinetics of Göynük oil shale, polystyrene and several polystyrene-oil shale blends were investigated by thermogravimetric analysis in the present study. Experiments were conducted at non-isothermal conditions with a heating rate of 5, 10 and 20 K min^?1 in the 298–1173 K temperature interval under an air atmosphere. Differential thermogravimetric data were analyzed by two different models. Effects of blending ratio of oil shale and polystyrene and heating rate on the combustion kinetics were investigated. Kinetic parameters were determined and the results were discussed.     

分子三维投影法在苯酚类化合物构效关系研究中的应用

对苯酚类化合物进行三维投影得到了5个形状参数,将其与3个Am指数及8个量子化学参数相结合.由最佳变量子集回归法对变量进行了压缩与选择,运用多元回归分析和人工神经网络法分别构造了预测数学模型,得到了满意的结果.     

系列甘露糖醛酸寡糖的制备与鉴定

用酸降解法制备了系列甘露糖醛酸寡糖(聚合度2～8),并分析测定了寡糖的结构. 褐藻胶经部分酸水解,于pH=2.85处分级获得聚甘露糖醛酸. 继续用酸降解法降解聚甘露糖醛酸,经凝胶柱层析分离纯化,获得系列甘露糖醛酸寡糖. 用荧光标记糖电泳(FACE)对寡糖进行了分析,并用电喷雾离子化质谱(ESI-MS)、 核磁共振波谱(NMR)及红外光谱(FTIR)进行了结构表征. 本研究用酸降解法制备饱和甘露糖醛酸寡糖,用凝胶柱层析法分离获得系列聚合度的寡糖,为褐藻胶大分子构效关系研究和药物的筛选与发现提供了重要的基础资料.     

CO2加氢合成二甲醚的催化剂的制备

先采用均匀沉淀法制备出CuO—ZnO催化剂,然后以CuO—ZnO催化剂作为晶核采用水热合成法制备出CuO—ZnO／HZSM-5（氢型ZSM-5分子筛）复合催化剂．利用X射线衍射和氨程序升温脱附手段对复合催化剂进行表征,并应用于CO2催化加氢合成二甲醚的反应．研究结果表明,在相同的反应条件下,这种CuO—ZnO／HZSM-5复合催化剂与采用物理混合法制备出的复合催化剂相比具有更好的催化效果,不但提高了CO2的转化率、二甲醚的选择性以及二甲醚和甲醇的总选择性,同时还改善了催化剂的稳定性．     

Feasibility of ETV-ICP-OES for Characterization of Archaeological Glasses

In the present study the possibilities of electrothermal vaporization inductively coupled plasma optical emission spectrometry (ETV-ICP-OES) for characterization of archaeological glasses were investigated. The objects of our research were fragments of a colorless late antique Roman flat window glass (fifth century A.D.) and colored medieval glass bracelets (eleventh–twelfth century A.D.) excavated in the region of Pernik (West Bulgaria).

The finely ground glass samples were analyzed directly and CHF₃ was used as evaporation and transport modifier. Dried aqueous standard solutions and certified reference materials with different matrix (glass, fly ash, and stream sediment) were used as calibration standards. No matrix effects were observed by the optimized conditions. Measurements were performed using common calibration curves obtained with all appropriate calibration standards and major, minor, and trace element concentrations were determined. ETV-ICP-OES analytical data were used to establish the type of glass, the fluxing agents, the typical coloring and decoloring elements, and the recipe norm.     

二级粘度液标准物质的研制

以基础油为原料研制了二级粘度液标准物质,对其均匀性和稳定性进行了考察,用方差分析法进行了评价,用标准毛细管粘度计对其进行了定值。实验结果表明,该粘度液标准物质的均匀性良好,稳定性在1年以上,量值准确可靠,达到二级标准物质的技术指标要求。     

Properties of aqueous solutions containing blends of poly-N-vinylformamide with carboxymethyl cellulose of various degrees of ionization and of composite films of these polymers

Rheological properties of mixtures of dilute and moderately concentrated aqueous solutions of poly-N-vinylformamide and carboxymethyl cellulose of various degrees of ionization were studied. Composite film materials were prepared, and their physicomechanical properties and structural organization were studied.     

Improving Accessibility and Reactivity of Celluloses of Annual Plants for the Synthesis of Methylcellulose

Pretreatments (water-soaking, pre-mercerization, mercerization under a pressure of 15 bars and steam explosion) were used to improve the accessibilities and reactivities of celluloses of bleached flax, hemp, sisal, abaca and jute pulps for the synthesis of methylcellulose. Degrees of crystallinity were determined by X-ray Diffraction (XRD) spectra. The iodine adsorption accessibilities of pulps were low and accessible fractions ranged from 1.3 to 5.2%. Accessible fractions in amorphous cellulose were calculated in the 5–18% range. The accessibilities of these pulps were hemp pulp > flax pulp > sisal pulp > jute pulp > abaca pulp. Fourier Transform Infrared (FTIR) spectra showed that mean hydrogen bond strengths were weakened and relative crystallinity indexes were decreased by pretreatments. The accessibility and reactivity of the abaca pulp were improved by water soaking, mercerization under 15 bars pressure, steam explosion and preliminary mercerization, of which steam explosion and pre-mercerization were the best treatments. Species was the main factor for the accessibility and reactivity.     

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.     

Dependence of structure of dehydrated PVA on the crystallinity of the original PVA

Poly(vinyl alcohol) (PVA) films having different crystallinities were prepared by elongating PVA films to different degrees and heating the films with and without elongation treatment at several temperatures between 60 and 200°C. Then, they were dehydrated by heating from 80°C to 230 or 330°C in hydrogen chloride gas. Infrared spectral measurements were made on the dehydrated PVA films obtained. Absorbances of the absorption bands due to several groups seen in the infrared spectra depended only on the density of original PVA films, regardless of its degree of elongation. From these dependences, it was found that the dehydration reaction progressed more easily in the crystalline region than in the amorphous region, that the aromatic rings with four or five adjacent hydrogen atoms were formed mainly in the amorphous region and those with two adjacent hydrogen atoms in the crystalline region, and that the aromatic rings with two isolated hydrogen atoms were formed in both the amorphous and crystalline regions. Relative concentrations of the groups of which the dehydrated PVA were composed were estimated. Comparison of the numbers of carbon atoms among the composing groups indicated that the main groups were the methylene group and the aromatic ring.     

Resolution of uncertainty of a four-stage sequential extraction procedure using analysis of variance

Sequential extraction procedures are mostly applied to soils and sediments. Investigations were made for testing the applicability of a selected extraction scheme on spoil pile material. Therefore, different spoil pile samples from uranium mining were extracted into four steps (exchangeable, reducible, oxidizable, and aqua regia soluble phase) and the contents of the elements Cr, Cu, Fe, K, Ni, and Zn were analyzed. To substitute the sequential extraction by a sequence of single extractions and thus keep uncertainties of extraction on a low level, both procedures were compared regarding conformity of their results. The effects of sample handling as well as those of analysis on the measured metal contents were determined by means of analysis of variance and sources of uncertainties were discussed.     

Effects of biosurfactants on surface properties of hematite

Application of microorganisms as surface modifiers has focused our attention in recent times. The adsorption of biosurfactants can be a way for the solid surface modification. In the present investigation rhamnolipids produced by Pseudomonas aerugiosa were used to make the hematite surface modification. Experiments were carried out with pure mineral hematite. In this paper, the influence of biosurfactant addition on both the stability and the flotability of hematite suspensions has been studied in detail. The stability experiments were conducted using Turbiscan LAb apparatus, at constant pH conditions and mineral amount. The flotation experiments were carried out using Hallimond tube. The adsorption isotherms of biosurfactant onto the hematite particles were also determined. The experiments were carried out with broth and pure rhamnolipid. The results of those experiments were compared and discussed.     

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。     

Evaluation of flow properties of dry powder inhalation of salbutamol sulfate with lactose carrier

The effects of the flow and packing properties of a drug/carrier powder mixture on emission of drug adhering to the carrier from capsules and inhalation devices were investigated. Model powder mixtures were designed consisting of lactose carriers with different particle shapes were prepared by surface treatment and micronized salbutamol sulfate. These powder mixtures were aerosolized by a Spinhaler, and in vitro deposition properties of salbutamol sulfate were evaluated by a twin impinger. The flow properties of the mixed powders were evaluated by the Carr's flowability index (FI) and Hausner's ratio (HR). The packing properties of the mixed powders were determined employing the tapping method. Compared with the powder mixed with the untreated lactose carrier, the FI, HR, and the constant K in Kawakita's equation of the powder mixture prepared using the surface-treated lactose carrier were significantly different, showing that the flow and packing properties of the drug/carrier powder mixture were improved. Using this surface-treated system, the handling of the powder mixture when packing into capsules is improved, which is desirable for handling dry powder inhalants. The fraction (%) of drug emitted from capsules and devices (EM) and the FI of the powder mixture were correlated. As the flow properties improved, the outflow of the powder mixture from capsules and devices became easier, and emission of drug adhering on the carrier from capsules and devices improved. Improvement of the inhalation process, such as the drug particles emitted from the inhalation system, is valuable for increasing inhalation properties of dry powder inhalation.     

跟踪高分子学科发展前沿，建设高分子物理国家精品课程

为建设高分子物理精品课程,近年来我们关注和跟踪高分子科学发展前沿,开设了"高分子材料流变学"、"高分子凝聚态物理"等新课,编著出版新教材。这些课程和教材的一个显著特点是不失时机地将学科发展的新动态、新成果引入研究生、本科生教学,提升高分子物理课教学质量。在编著新教材中,除介绍大量新知识、新思想外,还探索性地构建起新课程的理论体系和框架。     

Investigation of the possible role of fatty acids and alcohols as precursors of normal hydrocarbons generated during vacuum pyrolysis of a young kerogen

Significant amounts of fatty acids and alcohols, in addition to straight-chain hydrocarbons, were observed in the vacuum pyrolysate of a young kerogen isolated from a fresh-water sediment. The amounts and the distribution patterns of fatty acids and alcohols were compared with those indigenous to the original kerogen, as determined by solvent extraction followed by saponification extraction. Straight-chain fatty acids in the pyrolysate were 12.7 mg/g kerogen, while those extracted from the original kerogen were 10.5 mg/g. The amounts of fatty alcohols in the pyrolysate and in the extracts were 1.31 and 1.10 mg/g. respectively. The excess amounts in the pyrolysate were explained by the release of a strictly bound form of fatty acids and alcohols, which were left in the kerogen matrix even after the saponification extraction. The results indicated that most fatty acids and alcohols were not decomposed as a result of the vacuum pyrolysis and that neither fatty acids nor fatty alcohols should be viewed as the prime precursors of the straigth-chain hydrocarbons (4.6 mg/g) simultaneously generated during vacuum pyrolysis.     

Isolation and characterization of atropisomers of seven-membered-ring benzolactams

The atropisomeric properties of seven-membered-ring benzolactams (7a-c and 8a) [1,5-benzodiazepin-2-one (a), 1,5-benzothiazepin-4-one (b), and 1-benzazepin-2-one (c)] were examined. The atropisomers were isolated as the diastereomers with an (S)-phenethylamide moiety, which were characterized by X-ray crystallography, and the barriers to their interconversion were clarified.     

碳苷研究 V: 用Grignard试剂合成取代苯酚中酚羟基的保护及脱保护

本文报道了一些取代苯酚的合成, 并探讨了用Grignard试剂合成取代苯酚中酚羟基的保护及脱保护的问题. 利用苄基和甲基作为酚羟基的保护基, 对文献报道的切断醚键脱保护方法进行了评价. 找到了两种新体系能在更温和条件下切断醚键的方法, 指出了它们的适用条件. 实验结果符合硬软酸碱理论.