缔合溶液热力学性质与谱学性质的关联

缔合溶液具有与理想溶液显著不同的热力学和谱学性质,对于热力学和谱学的研究,有助于我们理解缔合溶液的特殊行为.谱学技术中核磁共振(NMR)、红外(IR)和拉曼(Raman)光谱是研究分子间相互作用和溶液结构等微观性质的有效方法,谱学已成为分子热力学研究体系"四面体结构"中的第四个顶点.本文对缔合溶液中热力学(汽液平衡和焓)和谱学(NMR,IR和Raman)联系的最新研究进展进行了综述,着重介绍相关的模型,如化学缔合模型、局部组成(LC)、格子流体氢键(LFHB)理论以及统计缔合流体理论(SAFT).     

纳米晶体材料研究进展

综述了目前纳米晶体材料合成、结构、性质和应用的研究和发展现状。通过惰性气体凝结、机械合金、等离子体技术和其他许多方法可以制得纳米晶体材料。尽管早期的研究者认为纳米晶体材料的晶粒边界结构不同于常规材料, 但目前有关纳米晶体材料结构的研究表明其具有与常规晶体材料相同的晶粒边界结构。纳米晶体材料所具有的诸如扩散和烧结、力学、陶瓷和金属间化合物的延展性、电学、热膨胀、光学、磁学、催化和腐蚀行为等性质优于常规多晶材料, 这些性质具有巨大的潜在应用价值。     

Changes in the standard transformed thermodynamic properties of enzyme-catalyzed reactions with ionic strength

The ionic strength has significant effects on the thermodynamic properties of ionic species and on the transformed thermodynamic properties of biochemical reactants at specified pH values. These effects are discussed for species, reactants, and enzyme-catalyzed reactions. This has led to three new thermodynamic properties: (z(j)(2) - NH(j)), (z(2) - N(H))(i), and Delta(r)(z((2)-N(H)), which are referred to as ionic strength coefficients. The first of these is a property of a species, the second is a property of a reactant, and the third is the property of an enzyme-catalyzed reaction. The effects of ionic strength on standard thermodynamic properties of species, standard transformed thermodynamic properties of reactants, and standard transformed thermodynamic properties of enzyme-catalyzed reactions are proportional to these new thermodynamic properties.     

Studies on Phosphorus-Containing Polymers. VI. Synthesis of Derivatives of Linear Phosphonitrile Chloride and Their Stability

The synthesis of LPNC and its derivatives and the hydrolysis and heat resistance properties of these materials are discussed. Lack of stability to water and depolymerization are adverse properties of many inorganic polymers. In the case of LPNC, it was found that these properties were probably due to the terminal ionic structure, and when the ionic part is removed from LPNC, the properties could be somewhat improved.     

Electrochemical Properties of Vanadium Oxide Aerogels and Aerogel Nanocomposites

The electrochemical properties of high surface area transition metal oxide aerogels are extremely interesting because aerogels serve to amplify surface effects. As a result, the electrochemical properties are dominated by surfaces rather than by bulk behavior. In the case of vanadium oxide aerogels this leads to extraordinary electrochemical properties, including an extremely high capacity for lithium and electrochemical responses that are both battery-like and capacitor-like. By exploiting sol-gel synthesis, it is possible to synthesize nanocomposite electrodes in which aerogels are in intimate contact with carbon nanotubes. The resulting nanocomposites exhibit superior electrochemical properties, especially at high discharge.     

Towards universal substituent constants: Parameterizing bond critical point properties with electronegativity descriptors

The properties of substituents have long been quantified by their effect elsewhere in a molecule. Ideally, intrinsic properties detailing the true properties of a substituent would be used. These properties are ideally transferable between molecules, to be robust and applied in different situations. Through a study on the bond critical point (BCP) properties of 117 substituents and 17 substrates we find that BCP properties from the quantum theory of atoms in molecules are not transferable between different bonded atoms. However, a substituent's changing electronegativity between substrates help quantify the observed variation. The relationship between changing electronegativities and critical point properties enables development of a relationship to predict critical point properties between a substituent and a new substrate, using only the electronegativity of a substituent attached to hydrogen, and the critical point property between the substituent and H.     

Melting properties of molten salts and ionic liquids. Chemical homology,correlation, and prediction

The application of the concept of chemical homology to describe melting properties of molten salts and ionic liquids (ILs) is analyzed. This concept was used several years ago to correlate and predict properties of solids and more recently to correlate melting temperatures of ILs. To analyze the characteristics of the extended method, this is first applied to melting properties of organic substances for which abundant data are available. The method is extended to analyze its applicability for properties of molten salts and ILs such as glass transition temperature, heat of melting, and entropy of melting. The foundation of the chemical homology concept is revised, and the difficulties for extending the method to correlate and predict melting properties of ILs are presented. Despite the difficulties, the homology concept can still be used with some conditions and limitations that are analyzed in this article. Several correlations are proposed.     

Vibrational energies,bonding nature,electronic properties,spectroscopic investigations and analysis of 3-bromo-4-Chlorobenzophenone

In this present study, we investigated pharmaceutically active of 3-Bromo-4-chlorobenzophenone. Structural, electronic properties (HOMO-LUMO, MEP) are investigated using DFT tool. Vibrational spectral analysis for FT-IR and FT-Raman are made of headline molecule. Electronic transition properties are discussed with the help of UV–Vis spectral analysis. Biologically active sites are found from MEP analysis. Electron delocalization properties are studied explored from HOMO-LUMO band gap energy. Moreover, intra molecular interactions are explained from NBO method. Molecular docking studies are performed to find the interactions various pathologies. The topological properties of the electron density have been analyzed.     

Viscoelastic properties of dendrimers in the melt from nonequlibrium molecular dynamics

The viscoelastic properties of dendrimers of generation 1-4 are studied using nonequilibrium molecular dynamics. Flow properties of dendrimer melts under shear are compared to systems composed of linear chain polymers of the same molecular weight, and the influence of molecular architecture is discussed. Rheological material properties, such as the shear viscosity and normal stress coefficients, are calculated and compared for both systems. We also calculate and compare the microscopic properties of both linear chain and dendrimer molecules, such as their molecular alignment, order parameters and rotational velocities. We find that the highly symmetric shape of dendrimers and their highly constrained geometry allows for substantial differences in their material properties compared to traditional linear polymers of equivalent molecular weight.     

Tensile strength of Iβ crystalline cellulose predicted by molecular dynamics simulation

The mechanical properties of Iβ crystalline cellulose are studied using molecular dynamics simulation. A model Iβ crystal is deformed in the three orthogonal directions at three different strain rates. The stress–strain behaviors for each case are analyzed and then used to calculate mechanical properties. The results show that the elastic modulus, Poisson’s ratio, yield stress and strain, and ultimate stress and strain are highly anisotropic. In addition, while the properties that describe the elastic behavior of the material are independent of strain rate, the yield and ultimate properties increase with increasing strain rate. The deformation and failure modes associated with these properties and the relationships between the material’s response to tension and the evolution of the crystal structure are analyzed.     

ePTFE functionalization for medical applications

Polytetrafluoroethylene (PTFE) is a ubiquitous material used in implants and medical devices in general due to its high biocompatibility and inertness; blood vessels, heart, jawbone, nose, eyes, or abdominal wall can benefit from its properties in the case of disease or injury. Its expanded version, ePTFE, is an improved version of PTFE with better mechanical properties, which extend its medical applications. However, ePTFE implants often lack improvement in properties such as antibacterial, antistenosis, or tissue integration properties. Improvements in these properties by several strategies of functionalization for medical purposes are discussed in this review. Covalent and non-covalent bonding are reviewed, including more specifically chemical impregnation, chemical surface modification, autologous vascularization, and cell seeding, which are strategies mainly used for improving the properties of ePTFE and are described in this review.     

Non-steady effective thermal properties of semi-infinite unidirectional fiber-reinforced composites using thermal wave method

Photothermal techniques and effective medium method combining with image method are applied to investigate the non-steady effective thermal properties of semi-infinite unidirectional fiber-reinforced composites, and the effect of the semi-infinite surface on the non-steady effective thermal properties is considered. The dispersion relation for the effective wave number in the semi-infinite random composites is derived. The image method is used to satisfy the adiabatic boundary condition at the semi-infinite surface. The numerical solutions of the non-steady effective thermal properties are obtained by using an iterative scheme. Analyses show that the variation of the non-steady effective thermal properties near the semi-infinite surface is significantly different from those of the infinite composite structure. The effects of the circular frequency of thermal waves, the volume fraction of fibers, and the properties contrast ratio on the maximum non-steady effective properties near the surface are examined. Comparison with the steady case is also given.     

Aqueous two-phase systems in biochemical recovery

The design and application of aqueous two-phase systems for recovery of proteins is reviewed. Reference is made to the properties of polymers and salt forming the systems and their influence on phase separation and partition. The properties of systems important for the design of purification strategies are discussed in relation to the surface properties of proteins. Strategies for the modification of systems for bioaffinity partition are considered including the choice of carrier in terms of molecular type and properties, or by particulate addition. Finally, the scaleup of partition is considered, and the reasons for currently limited adoption at larger scales are elucidated.     

Thiophene,Selenophene, and Tellurophene‐based Three‐Dimensional Organic Frameworks

3D frameworks are important because of their potential to combine the advantageous properties of porous materials with those associated with polymers. A series of novel 3D aromatic frameworks are presented that incorporate the heterocycles thiophene, selenophene, and tellurophene. The specific surface area and pore width of frameworks depends on the element that is used to build the framework. Optoelectronic properties are element‐dependent, with heavy atoms red‐shifting the optical properties and decreasing the energy gap of the solid. The metalloid nature of tellurophene allows the properties of this material to be tuned based on its oxidation state, even as an insoluble solid. The incorporation of the optoelectronic active thiophene, selenophene, and tellurophene units and the effect that they have on properties was studied. A supercapcitor device was fabricated using these frameworks, showing that these 3D frameworks are promising for optoelectronic uses.     

A corresponding states treatment of the liquid–vapor saturation line

In this work we analyze correlations for the maxima of products of some liquid–vapor saturation properties. These points define new characteristic properties of each fluid that are shown to exhibit linear correlations with the critical properties. We also demonstrate that some of these properties are well correlated with the acentric factor. An application is made to predict the properties of two new low global warming potential (GWP) refrigerants.     

Thiophene,Selenophene, and Tellurophene‐based Three‐Dimensional Organic Frameworks

3D frameworks are important because of their potential to combine the advantageous properties of porous materials with those associated with polymers. A series of novel 3D aromatic frameworks are presented that incorporate the heterocycles thiophene, selenophene, and tellurophene. The specific surface area and pore width of frameworks depends on the element that is used to build the framework. Optoelectronic properties are element‐dependent, with heavy atoms red‐shifting the optical properties and decreasing the energy gap of the solid. The metalloid nature of tellurophene allows the properties of this material to be tuned based on its oxidation state, even as an insoluble solid. The incorporation of the optoelectronic active thiophene, selenophene, and tellurophene units and the effect that they have on properties was studied. A supercapcitor device was fabricated using these frameworks, showing that these 3D frameworks are promising for optoelectronic uses.     

直链烷烃结构型和凝聚型性质的递变规律研究

用图示法和非线性规划的方法对直链烷烃同系物最高成键分子轨道能级、最低成键分子轨道能级,电离电位、氧化半波电位、正常沸点、正常熔点、临界压力、临界温度、密度、折光率、表面张力和粘度等12种结构型性质和凝聚型性质的变化规律进行研究,结果发现直链烷烃结构型性质和凝聚型性质一般能遵守同系对数递变规律,各种结构型性能和凝聚型性能均与对数递变函数呈优良的相关性,相关系数均大于0.99．用同系对数递变规律对直链烷烃各种性能进行预测的结果表明,除少数同系列起始化合物的偏差较大外,大多数预测值与实验值非常吻合,实验散点几乎与对数递变函数曲线相重合．     

A comprehensive investigation in determination of nanofluids thermophysical properties

In recent years, research on heat transfer and related equipment has been one of the topics of interest in many different industries. The use of conventional fluids in heat transfer due to their low thermal properties has created problems in this area, so the use of nanofluids in many cases has been a solution to overcome this problem. The parameters affecting the thermophysical and thermal properties of nanofluids are temperature, concentration, size, shape, pH, surfactant and ultrasonic time, among which temperature and concentration have the greatest effect. Existing models and studies in the field of nanofluids are limited to the type of nanoparticles and base fluids and their operating range, and there is no comprehensive model for predicting thermal properties. In the present study, models and theories regarding the determination of thermal conductivity of nanofluids and other thermophysical properties have been comprehensively compiled and the mechanisms for increasing the thermal properties as well as the effective parameters and the effect of each of them on improving the properties are presented. In general, the results showed that thermal properties improve with increasing concentration and temperature. Finally, the role of nanofluids effect on thermal performance in the heat exchangers is studied and the results are summarized.     

Physicochemical control of foam properties

This article summarizes our recent understanding on how various essential foam properties could be controlled (viz. modified in a desired way) using appropriate surfactants, polymers, particles and their mixtures as foaming agents. In particular, we consider the effects of these agents on the foaminess of solutions and suspensions (foam volume and bubble size after foaming); foam stability to liquid drainage, bubble coalescence and bubble Ostwald ripening; foam rheological properties and bubble size in sheared foams. We discuss multiple, often non-trivial links between these foam properties and, on this basis, we summarize the mechanisms that allow one to use appropriate foaming agents for controlling these properties. The specific roles of the surface adsorption layers and of the bulk properties of the foaming solutions are clearly separated. Multiple examples are given, and some open questions are discussed. Where appropriate, similarities with the emulsions are noticed.