亚麻的化学组成和微观结构对染色性能的影响

本文通过X衍射法、纤维化学成分分析法测试了亚麻纤维的微观结构、化学成分，通过对亚麻进行液氨整理改变其结晶度和取向度，从而测得亚麻的结晶度和取向度对染色性能的影响，利用碱煮、H2O2和NaOCl漂白处理降低了亚麻中木质素和半纤维素的含量，从而测量得木质素和半纤维素含量对亚麻上染率的影响。结果表明亚麻的上染率随着结晶度的降低呈线性上升，随着取向度的降低而上升；随着木质素和半纤维素含量的降低而呈上升趋势。     

Impact of the physical and topographical characteristics of adsorbent solid-phases upon the fluidised bed recovery of plasmid DNA from Escherichia coli lysates

A comparison is made of the performance of two types of adsorbent solid phases (commercially sourced Streamline composites and custom-assembled Zirblast pelliculates), derivatised with similar anion exchange chemistries and applied to the recovery of plasmid DNA from Escherichia coli extracts prepared by chemical lysis and coarse filtration. Streamline and Zirblast adsorbents were characterised by average particle diameters of 200 and 95 microm, densities of 1.16 and 3.85 g/m2, and small ion capacities of 170 and 8 micromol/ml settled adsorbent, respectively. Detailed analysis of products and impurities in a full operational cycle of adsorption, washing, pre-elution, elution and regeneration processes was enabled by the harnessing of a battery of analyses for nucleic acid and organic solute content of feedstocks and bed effluents exploiting ultra-violet spectrophotometry, agarose gel electrophoresis and specific reactions with the fluorescent probe PicoGreen. In comparative tests operated under near identical conditions, Streamline and Zirblast adsorbents exhibited plasmid recoveries of 76 and 90% of bound product characterised by purity ratios (relative PicoGreen and A254 estimates of mass) of 9 and 32, respectively. Conclusions are drawn regarding the specific impact of the physical and topographical characteristics of solid-phase geometry upon product throughput, achievable product purity, process time-scales and operational economics for the manufacture of plasmid DNA.     

色质联用仪生物标志物数据库的建立与扩展

随着我国石油工业的发展和色质联用仪广泛应用，生物标志化合物的鉴定与研究越来越重要。由于目前缺少完整的和系统的生物标志物数据资料．研究人员往往要花费大量的时间寻查文献，许多化合物无法鉴定，本谱库针对有机地球化学家们鉴定生物标志物的迫切需要以及弥补现有商业质谱数据库的不足，作者长期积累和广泛收集各类生物标志物的质谱数据文献，建立了有机地球化学研究工作中各类生物标志物的质谱库。该库提供化合物名称、分子式、分子峰、基峰、质谱强度等。     

能量色散X射线荧光光谱法分析金元时代的钧窑瓷器

应用能量色散X射线荧光光谱法测定了16个金元时期钧窑瓷器胎、釉样品的化学组成。由结果可知:金元钧瓷胎具有低硅高铝的北方瓷器特点,釉则多为钙碱釉。金元时期样品与北宋时期钧窑瓷器胎釉化学组成比较,金元时期钧窑样品的化学组成变化较大,从因子分析散点图可见,北宋钧官窑样品化学组成变化不大;金元钧窑与北宋钧民窑样品制作工艺上存在继承和发展的关系,但金元时期对原料选择和配方的控制已不如北宋时期严格,反映出金元时期的钧窑已处于衰落阶段。     

Relevance of analytical pyrolysis studies to biomass conversion

The principles and methods of soft ionization mass spectrometry in combination with pyrolysis of macromolecules are outlined. Essential features of the newly developed techniques are the extension of the recorded mass range and the almost exclusive formation of molecular ions of the pyrolyzates. Using field ionization and field desorption mass spectrometry at low and high mass resolution, with electrical and photographic detection, pyrolysis products of biomass were analyzed for the first time. The results of flash pyrolysis by Curie-point heating and thermally programmed degradation of biopolymers are compared.The main topic is the evaluation of the methodology for time- and temperature-resolved pyrolysis. The thermograms and pyrolysis mass spectra obtained enable the study of pyrolysis reactions and the chemical fingerprinting of complex biological matter. The kinetics for the devolatilization of individual chemical species or classes of compounds can be monitored. Curie-point pyrolysis of biopolymers such as kappa-carrageenan and time-programmed degradation of cellulose and lignin are reported. Furthermore, preliminary investigations of pine wood and coal illustrate the potential of the introduced methods.     

Electrical processes upon the evaporation and condensation of water and ice

A mathematical model of electrical processes that take place upon the evaporation of water and sublimation of ice, as well as the condensation growth of water and ice phases from vapor, is proposed. The transfer of the main charge carriers, such as (i) protons and hydroxide ions (in ice, water, and vapor and (ii) orientational defects (in ice and water) is taken into account. Upon the evaporation of water and the sublimation of ice, the first carriers are accumulated before the phase front and cause positive charges in the surface of the water and ice, while the second carriers are depleted (their concentration becomes lower than the thermodynamic value) and impart a negative charge to water and ice. The contribution of protons and hydroxide ions dominates at a low rate of evaporation. In the condensation of vapor and relevant growth of water and ice phases, the polarity of surface charge is opposite to that observed upon evaporation. The values of interfacial current and signs of phase charges upon sublimation, evaporation, and condensation that are predicted in the model comply with experimental data.     

Herkunft und Authentizität von Lebensmitteln: Stabilisotopenanalytik

The correlations between isotope ratios in water, organic mass, and trace elements of food and beverages, and the circumstances and sites of their origin and production are outlined, and the methods of mass spectrometric isotope ratio determination and the positional ²H analysis by quantitative NMR measurement are explained. In context with the application of these methods for origin and authenticity investigations of food, examples are given for the proof of watering or sugar addition to wine and fruit juices and methods for the identification of nondeclared additions of L‐malic and Lascorbic acids are described. The possibilities of multielement isotope ratio analysis for the identification of origin of animal products (eggs, milk products, meat) and methods for the discriminations between natural and nature identical aroma compounds are outlined. Finally, the possibilities of isotope ratio measurements for the discrimination between plant and animal food from conventional and organic production are discussed.     

Effect of reaction medium on the radical polymerization and copolymerization of potassium and sodium p-styrenesulphonate

The kinetics of the homogeneous free radical polymerization of potassium p-styrenesulphonate and sodium p-styrenesulphonate (SSS) in water-salt, water-dioxane, water-dimethyl sulphoxide (DMSO), DMSO—dioxane mixtures and copolymerization of SSS with acrylamide in water-salt and water-DMSO mixtures have been investigated. The overall rate of the process, the kinetic orders with respect to monomer and initiator, overall activation energy and also the properties of the resulting polymers (molecular weight, copolymer composition and compositional inhomogeneity) depend on the nature of the reaction medium. It is mainly connected with the influence of ionic strength (due to varying ionogenic monomer concentration, addition of salts and also the change of the conversion degree) and with the influence of the polarity of solvent on the rate constants for propagation and termination. The chemical and physical characteristic of the reaction mainly influence parameters of the electrostatic interactions in the system “macroradical-counterions-anions of monomer”. This leads to conformational variation of polymer chains and influences the reactivities of growing macroradicals and ionogenic monomers in polymerization and copolymerization. Data on conductivity and viscometric measurements confirmed the dependence of the conformation of polymer and copolymer macromolecules upon the composition of the medium.     

宝日希勒褐煤在合成气与复合溶剂系统下的液化性能研究

在合成气（CO+H₂）与复合溶剂（水+有机溶剂）液化系统下研究了气氛、温度、催化剂类型对宝日希勒褐煤转化率、油气水产率和CO转化率等液化特征的影响,从而探讨其液化性能。结果表明,在高含水复合溶剂系统中,合成气气氛、反应温度430-450℃适宜宝日希勒褐煤液化转化,转化率可达到81.15%,油气水产率达到71.53%。该液化系统下,含铁、碱和硫复合型催化剂能有效地提高液化转化率和油气水产率,在430℃催化液化下褐煤转化率达92.27%,油气水产率达79.39%。该催化剂有效促进了煤中大分子的裂解和系统中水煤气变换反应进程,沥青质减少,油含量增多。液化油中多环芳烃衍生物在催化液化过程中向单环芳烃衍生物和烷烯烃转化,分子量降低,提高了油品质量。     

基于非接触式拉曼光谱分析人血与犬血的PCA-LDA鉴别方法

将拉曼光谱分析法与数理统计方法有机结合,构建人血与犬血种属判别模型,实现了不同种属血液样本的高效无损鉴别.采用拉曼光谱的无损测试模式对血液样本进行测试,考察了抗凝管管材、聚焦位置及曝光时间等对血液样本拉曼光谱的影响,在激发波长为632.8 nm,光谱扫描范围为200~1800 cm-1,功率衰减率50%,曝光时间5 s及累加次数为2次的优化条件下,获得了无损检测条件下的血液样本拉曼光谱图.针对血液样本组分复杂、拉曼光谱信号基底背景高等问题,提出了基于小波变换去噪,进行分段多项式基线校正的预处理方法,有效解决了血液样本拉曼光谱谱图的高噪音和基线漂移问题.实验选择30例正常人血和33例比格犬血为样本训练集,5例正常人血和5例比格犬血为测试集,基于主成分分析法(PCA)联合线性判别法(LDA)模型,训练集分类正确率达到95.23%,盲测集分类正确率达90.00%.这种基于非接触式血液样本拉曼光谱和PCA-LDA判断模型的测试方法在进出口检验检疫等涉及血液无损鉴别的领域具有广泛的应用价值和前景.     

双定性双定量相似度法评价银杏达莫注射液的高效液相色谱指纹图谱

建立了色谱指纹图谱的双定性双定量相似度评价法,并应用于银杏达莫注射液的高效液相色谱（HPLC）指纹图谱的评价。采用反相HPLC,以芦丁为参照物峰,确定了41个共有峰,建立了银杏达莫注射液的对照指纹图谱。以双定性相似度S和S′、双定量相似度C和P评价银杏达莫注射液的HPLC指纹图谱,分别考察在大峰缺失和小峰缺失两种情况下,4个相似度指标的变化特征。S能反映化学成分的分布比例,受大峰影响严重,无法反映小峰的丢失; S′对所有指纹峰等权,反映小峰缺失灵敏,二者构成双定性相似度。C能反映样品共有峰的总体含量,但受大峰影响严重,无法反映小峰的缺失; P对所有峰积分值等权,能较好地反映小峰的变动,二者构成双定量相似度。因此,由S与S′、C与P构成的双定性双定量相似度法能同时监测大峰和小峰的变动与缺失,能准确地解决色谱指纹图谱的宏观定性和定量评价问题。同时还提出了方向余弦作为对照指纹图谱的特征指纹的概念和分解相似度的概念,以此考察了各指纹峰对相似度贡献的大小及其在不同程度缺失时4种相似度的变化情况。所建立的HPLC对照指纹图谱可用于银杏达莫注射液的质量控制。     

Permanent iridium modifier deposited on tungsten and zirconium-treated platforms in electrothermal atomic absorption spectrometry: vaporization of bismuth,silver and tellurium

The stabilizing role of permanent iridium modifier deposited on tungsten-treated (WTP) and zirconium-treated (ZrTP) platforms of transversely heated graphite atomizer (THGA) was studied in detail by electrothermal atomic absorption spectrometry (ETAAS) and different surface techniques in model experiments for Ag, Bi and Te. The comparison of the stabilizing efficiency of permanent Ir modifier on WTP and ZrTP and each of the single components, reveals the better effect of Ir on WTP and Ir itself. The extent of analyte losses during pre-atomization and the strength of analyte association with the modifier were estimated by the plotting of `differential vaporization curves'. The existence of double peaks of Ag, Bi and Te in WTP and Ir on WTP was confirmed and possible reasons for their formation were discussed. The absorbance profiles presented as differential curves reveal an existence of at least two different types of precursors determining processes of atom generation. The observed differences in the behavior of Ir permanent modifier on WTP and ZrTP, respectively, were explained by the different extent of iridium–tungsten and iridium–zirconium interaction and surface distribution. XRF, ESCA and SEM studies reveal non-uniform distribution of the modifier on the graphite substrate and the presence of oxide containing species on the surface.     

生血宁片中Fe元素的形态分析方法研究

为对生血宁片中Fe元素的形态进行分析,采用了溶剂法、树脂法制备相应供试品溶液,通过微波消解与ICP-MS法测定了生血宁片中Fe元素的含量,并进行了形态研究。结果表明,生血宁片中Fe元素主要以稳定态形式存在,既以有机态又以无机态形式存在,且主要以Fe2+的稳定结合态的形式存在。通过离子树脂筛选出不同价态的铁元素,为价态的分离提供一新方法,且进一步证明了Fe元素的起效形式,同时为中药材或中成药的质量控制及药理研究提供理论参考。     

Structure of crystalline polymers with unbranched long side chains

The structure and thermodynamic properties of atactic and isotactic acrylic and methacrylic polymers containing 16–18 carbon atoms in the n-aliphatic side chains, and of copolymers of hexadecyl acrylate with isopropyl acrylate were studied by means of x-ray and differential thermal analysis. The crystallization of branched acrylic and methacrylic polymers and of acrylic copolymers proceeds in the form of a hexagonal crystal, regardless of the configuration of the backbone chain. Methods of ordering branched macromolecules are proposed, and the melting points, heats and entropies of fusion determined. The role of flexibility of the backbone chains in ordering and the crystallization processes was determined. In the case of poly(n-alkyl acrylates) the backbone chain is involved in the crystalline lattice; this is not the case in methacrylates and copolymers of hexadecyl acrylate with isopropyl acrylate. Some similarity was assumed between the structure of biopolymers and synthetic branched polymers.     

Solid phase extraction of uranium and thorium on octadecyl bonded silica modified with Cyanex 302 from aqueous solutions

A simple and reliable method for rapid extraction and determination of uranium and thorium using octadecyl-bonded silica modified with Cyanex 302 is presented. Extraction efficiency and the influence of various parameters such as aqueous phase pH, flow rate of sample solution and amount of extractant has been investigated. The study showed that the extraction of uranium and thorium increase with increasing pH value and was found to be quantitative at pH 6; and the retention of ions was not affected significantly by the flow rate of sample solution. The extraction percent were found to be 89.55 and 86.27 % for uranium and thorium, respectively. The maximal capacity of the cartridges modified by 30 mg of Cyanex 302 was found to be 20 mg of uranium and thorium. The method was successfully applied to the extraction and determination of uranium and thorium in aqueous solutions. The percentage recovery of uranium and thorium in a number of natural as well as seawater samples of Iran were also investigated and found to be in the range of 85–95 %.     

Carbenes and Nitrenes: Recent Developments in Fundamental Chemistry

Carbenes and nitrenes can exist in both singlet and triplet states, sometimes equally stable and interconverting either thermally or photochemically. Many carbene and nitrene reactions proceed via tunneling at low temperatures. Numerous singlet and triplet states have been characterized spectroscopically, and a detailed understanding of the chemical and physical properties of carbenes and nitrenes is emerging. There has been significant progress in the direct observation of carbenes, nitrenes, and many other reactive intermediates in recent years through the application of matrix photolysis and flash vacuum pyrolysis linked with matrix isolation at cryogenic temperatures. Our understanding of singlet and triplet states has improved through the interplay of spectroscopy and computations. Bistable carbenes and nitrenes as well as many examples of tunneling have been discovered and numerous rearrangements and fragmentations have been documented. The correlation of the zero‐field splitting parameter D with calculated spin densities on nitrenes and carbenes is discussed. This Minireview gives an overview of some of these developments.     

Excited state properties of novel p- and n-type organic semiconductors with an anthracene unit

Photoinduced dynamics of novel p- and n-type organic semiconductors with an anthracene unit are theoretically investigated with quantum chemistry methods. The calculated vertical absorption and fluorescence frequencies of them are consistent with the experimental data. The changing tendencies of the dihedral angles between anthracene unit and trifluoromethylphenyl (or thiophene) in the photoinduced dynamics processes (vertical absorption and vertical fluorescence) are examined from the geometries of optimized ground and excited states. To study the influence of the individual units of the derivatives to the excited state properties of the derivatives, the energies and densities of frontier orbital HOMOs and LUMOs of the individual unit and the derivatives are studied in the processes of vertical absorption and fluorescence. The excited state properties of the two derivatives in the processes of vertical absorption and fluorescence are studied with 2D and 3D real space analysis methods, which are employed to study the electron–hole coherence and the excitation delocalization (with transition density matrix method), and charge and energy transfer (with transition and charge difference density method). Overall, the computed results remain in good agreement with the relevant experimental data, and the theoretical results promote deeper understanding to the optical and electronic properties of the semiconductor in the process of photoinduced dynamics.     

Enzyme Mimics: Advances and Applications

Enzyme mimics or artificial enzymes are a class of catalysts that have been actively pursued for decades and have heralded much interest as potentially viable alternatives to natural enzymes. Aside from having catalytic activities similar to their natural counterparts, enzyme mimics have the desired advantages of tunable structures and catalytic efficiencies, excellent tolerance to experimental conditions, lower cost, and purely synthetic routes to their preparation. Although still in the midst of development, impressive advances have already been made. Enzyme mimics have shown immense potential in the catalysis of a wide range of chemical and biological reactions, the development of chemical and biological sensing and anti‐biofouling systems, and the production of pharmaceuticals and clean fuels. This Review concerns the development of various types of enzyme mimics, namely polymeric and dendrimeric, supramolecular, nanoparticulate and proteinic enzyme mimics, with an emphasis on their synthesis, catalytic properties and technical applications. It provides an introduction to enzyme mimics and a comprehensive summary of the advances and current standings of their applications, and seeks to inspire researchers to perfect the design and synthesis of enzyme mimics and to tailor their functionality for a much wider range of applications.