Dynamics of large-scale fluctuations in native proteins. Analysis based on harmonic inter-residue potentials and random external noise

The fluctuations of residues of proteins about their equilibrium configurations are analyzed by the Langevin equation. Residue pairs that are covalently bonded and those that are within a given cutoff distance of each other are assumed to be connected by linear springs. The actions of the solvent and intramolecular interactions on each residue are treated as random noise. The correlations of fluctuations resulting from the solution of the Langevin equation are observed to be identical to those obtained by the Gaussian Network Model based on equilibrium statistical mechanics. The time-delayed correlations of fluctuations, and the response of the protein to a given frequency and to a window of frequencies are determined. The fluctuations of the residues resulting from a given fixed externally applied frequency are evaluated for different modes of the system. Synchronous and asynchronous components of correlations for different modes are formulated. The findings of the present paper are applied to the 241 residue protein S. marcescens endonuclease (1QL0).     

膨胀石墨与活性炭对工业油吸附性的对比研究

选用膨胀体积为150、250、350 mL/g的膨胀石墨和活性炭为吸附剂,以汽油、煤油、柴油、真空泵油和汽机油为吸附质,采用重量法测定了吸附剂对吸附质的吸附性能,实验结果表明：膨胀体积为350 mL/g的膨胀石墨对吸附质的吸附量分别为40、47、52、64、70 g,活性炭的吸附量分别为3.02、3.04、3.08、3.1、3.4 g;膨胀石墨的滞留吸附量分别减少至8、10、17、24、30 g,活性炭的滞留吸附量变化不大.对比了不同膨胀体积的膨胀石墨和活性炭对吸附质的吸附性能,膨胀体积越大,吸附量越大.用SEM和TEM对膨胀石墨的形貌进行了表征,探讨了吸附和滞留吸附的机理.     

有机电致发光功能色素材料的研究

介绍了有机电致发光材料的发展过程，阐述了空穴、电子传输材料。详细叙述了发光材料尤其是悬挂体系有机电致发光材料。提出了研究新材料的意义。     

止汗除臭剂研究进展

根据文献 ,对大汗腺和小汗腺所分泌的汗液组成进行了对比 ,并探讨了汗臭形成的机理。对止汗除臭剂的活性物质、作用机理、使用方式等方面的研究进展进行了综述。介绍了止汗除臭剂功效评价方法的原理、特点和研究进展。并对我国止汗除臭剂市场前景进行了分析。     

数控机床防腐涂装技术的研究

详细阐述了金属腐蚀的危害机理,分析了影响数控机床腐蚀的因素,介绍了防腐涂料及防腐技术在数控机床上的应用现状,提出了数控机床整机防腐的对策及防锈措施。     

甲基二氯硅烷-甲基三氯硅烷-甲苯三元体系等压汽液平衡

In this paper, the boiling points of methyldichlorosilane-methyltrichlorosilane-toluene system and of the three binary systems are determined at 101.3 kPa with a new type of magnetic pump-ebulliometer.The VLE data of the three binary systems, respectively,are correlated with the Margules, van Laar, Wilson, and NRTL equations. The equilibrium composition of the vapor phase of three binary systems are calculated from TPX by indirect method. Activity coefficients are calculated after accounting for the nonideality of the vapor phase. The model parameters of liquid activity coefficient are correlated by the least square method. The vapor pressure of the pure components are obtained by using Antoine constants from the literature. The VLE data of ternary system are predicted by the Wilson equation. The calculated boiling points show good agreement with the experimental data.     

世界洗涤剂醇的市场现状及发展趋势

介绍了世界洗涤剂醇的生产能力和供需情况，对洗涤剂醇的市场状况及消费现状进行了分析。指出国内洗涤剂醇的一些应用领域，对今后洗涤剂醇的发展提出了建设性的建议，并对洗涤剂醇的未来趋势进行了预测。     

分光光度法测定天然多酚类化合物含量的研究进展

介绍了近年来分光光度法在测定天然多酚类化合物方面的研究进展。综述了测定天然多酚类化合物方法的应用范围,对测定方法按化学反应进行分类,如络合反应、氧化还原反应、亲核加成反应和重氮化-偶合反应等,并探讨了测定方法的反应原理及测定方法中存在的问题,对今后的研究方向作了展望。     

纳米铁的改性及其去除氯代有机物研究进展

回顾了氯代有机物的污染现状及其传统治理技术,简要介绍了纳米铁的制备方法,重点总结了采用物理辅助法、化学添加剂法以及载体固定法对纳米铁改性的新进展,分析了改性纳米铁的脱氯效果及其影响因素,提出了纳米铁环境修复技术尚存在的问题以及该技术的应用前景。     

羊毛角蛋白-聚乙烯醇再生纤维的结构性能表征

从废旧毛涤混纺面料中提取出羊毛角蛋白,配制角蛋白含量不同的3种纺丝液,通过静电纺丝方法得到羊毛角蛋白-聚乙烯醇(PVA)再生纤维。用扫描电镜观察、红外光谱分析及热学性能分析发现:3种羊毛角蛋白-PVA再生纤维膜中的纤维分布均匀、相互交叉,直径在230~260 nm左右;3种再生纤维的红外光谱都具有明显的角蛋白与PVA的特征;3种再生纤维膜的热稳定性差异不大。     

第二代生物柴油的研究现状与展望

分析了制备第二代生物柴油的反应机理,叙述了第二代生物柴油三种主要生产工艺,即油脂直接加氢脱氧工艺、加氢脱氧临氢再异构工艺和柴油掺炼工艺,归纳了3种工艺的优缺点,指出了第二代生物柴油发展面临的问题及解决方向,并对第三代生物柴油的发展现状与前景进行了综述与讨论。     

Preparation of Silver Nanopowder by Freeze-Drying Procedure

A freeze-drying procedure is developed for manufacturing silver nanopowder with regular shape and uniform diameter. The procedure includes four steps: preparing the precursor solution, freezing the solution, drying the congelation, and calcining the drying product. The starting substances are silver nitrate and caustic soda and the precursor is diammine silver solution. Three freezing styles including direct freezing, vacuum evaporation freezing, and spray freezing are adopted to freeze the precursor solution. In the drying stage, two heating styles for the frozen solution are compared. X-ray diffraction (XRD) and energy disperse spectroscopy (EDS) spectrograms show that the products of freeze drying are pure amorphous silver nanopowder without hard agglomerations. Silver cubic nanocrystals are subsequently obtained by calcination. The chemical fundamentals and the drying curves of freeze drying are given. The processes of preparing silver nanopowder are described in detail. The effect of freezing and heating on characteristics of the powder are discussed. The mechanism of grain forming and growing up is analyzed according to the observation results. The characteristics of powder freeze drying and its feasibility for volume production are presented.     

甲基三氯硅烷、甲基乙烯基二氯硅烷、甲苯的二元及三元体系等压汽液平衡

引　言甲基乙烯基二氯硅烷是重要的有机硅单体和硅烷偶联剂 ,在硅橡胶、涂料、印染、化妆品等领域有着广泛的应用 .在合成甲基乙烯基二氯硅烷的过程中 ,甲苯作为均相催化剂的载体以及反应的媒介体循环使用 ,甲基三氯硅烷是副产物 ,在分离过程的设计中需要有关甲基三氯硅烷、甲基乙烯基二氯硅烷、甲苯体系的汽液平衡数据 ,此前文献尚未见报道 .为了满足过程开发与工程设计的需要 ,本研究测定了甲基三氯硅烷、甲基乙烯基二氯硅烷和甲苯三元体系及其 3个二元体系的相平衡数据 ,并进行了热力学关联 .1　实验部分1 1　试　剂甲基三氯硅烷 :江西蓝…     

回收NMP-CS2混合溶剂萃取原煤基本性状研究

以平顶山煤和徐州煤为原料,利用回收NMP与CS_2混合溶剂和反萃取剂将两种煤全组分分离成萃余煤组分、沥青质组分、精煤组分和轻质组分四大族组分,主要对比原煤及各族组分的真密度、工业分析与元素分析。结果表明,萃余煤组分真密度最大,分别为1.59和1.45,精煤组分与沥青质组分真密度低于原煤。轻质组分具有较多非共价键成键点,易与水分子形成氢键,水分含量最高,分别为6.09%和5.77%,而萃余煤组分水分含量最低,分别为0.96%和0.63%。沥青质组分接近无灰。挥发分含量以轻质组分沥青质组分精煤组分原煤萃余煤组分顺序降低。C元素含量以精煤组分与沥青质组分相对较高,萃余煤组分C元素含量较两者偏低,分别为80.91%和80.65%。轻质组分中N、O和S元素含量较高,C元素含量最低。     

Verification of numerical simulation of the self-assembly of polymer-polymer-solvent ternary blends on a heterogeneously functionalized substrate

The directed self-assembly of polymer-polymer-solvent ternary blends on heterogeneously functionalized substrate is investigated with a three dimensional numerical model. The numerical simulation results are quantitatively verified by the experimental results. The phase separation of PS-PMMA-DMF blends are spin coated on a substrate functionalized by ODT/₂NH on Au surface. While many simulation parameters are set to the experimental conditions, other unmeasurable material constitutive model parameters are estimated from the real experiment observations. The effects of the spin speed, pattern periodicity, PS/PAA composition ratio, and the PAA molecular weight are investigated in both the experiments and numerical simulation. The simulation results are verified by comparison to the experimental results. During the verification process, numerical optimization methods are employed to determine the unmeasurable physical parameters. Quantitative methods are introduced for assessment of the results.     

聚合物挤出加工中温度分布的计算、测量与控制

介绍了聚合物挤出加工中关于温度分布研究的进展,对温度分布计算方法进行了分析对比,说明了各种方法的适用范围,同时对各种温度测量方法作了简要介绍,说明了测量方法特性,最后对温度控制方法进行了分析,介绍了各种方法的应用。系统分析表明,采用数值模拟方法是温度分布计算的发展方向。     

Metal–Oxide Interactions on Copper-Segregated and Copper-Deposited TiO2 Rutile (001) Surfaces

Scanning tunneling microscopy and spectroscopy are used to study local electronic variations across a surface containing one monolayer of copper on TiO₂ rutile (001). The interactions that occur at the metal–oxide interface when the sources of the copper are segregation from the bulk and ultra-high-vacuum deposition are compared by characterizing the associated surface morphologies and electronic properties. The morphologies of these surfaces are similar in that the copper forms clusters; they are dissimilar in that copper features exist on two size scales on the segregated surface, whereas the deposited copper clusters are uniform in size and are aggregated. The electronic properties of the two surfaces also are found to differ: the copper-segregated surface is insulating, whereas the copper-deposited surface is conductive. The electronic properties are discussed in terms of the effects of surface-charge and ionic-charge concentration gradients.     

氢气锅炉点火控制分析

介绍了氢气锅炉的基本组成,深入阐述了锅炉点火控制系统各部分原理,并根据该装置在实际运行中暴露出来的问题进行了设计缺陷分析,提出了相应的解决方法。     

用于液体除湿的椭圆中空纤维膜管束管间传递现象

研究了用于液体除湿的椭圆中空纤维膜管束管间纵向动量与热量传递现象。选择了四边形和三角形排列这两种规则排列管束中的两根纤维管和管间流体为研究对象,建立控制管间纵向流体流动与传热过程的偏微分方程,并采用贴体坐标转换法对控制方程进行有限容积离散与求解,获得了计算单元内的阻力系数和Nusselt数,分析了流道内局部Nusselt数的变化特征以及纤维管排布（三角形和四边形排列）、管径比、椭圆半轴比以及壁面边界条件（等壁温或等热通量边界）的影响。研究结果可为用于液体除湿的椭圆中空纤维膜管束的结构设计和性能评价提供基本理论及数据基础。     

催化裂化装置模拟研究与进展

分析和介绍了国内外催化裂化装置建模和稳态模拟方面的研究和进展。对催化裂化反应集总方法及相应的反应网络进行归纳,并讨论其优缺点;推导了动力学模型方程并着重探讨方程求解算法以及模型中动力学参数、催化剂失活因子和装置因素的估计方法。