Discrete Integrators Based on Superionic Conductors: Perspective for Measuring the Amount of Electric Energy

The possibilities of using discrete integrators based on superionic conductors in a device for measuring the electric energy consumption in local networks are considered. The device is easily assembled at the working place. The system can also be used for measuring both the spent charge (ampere-hours) and the amount of consumed energy. When measuring, recording, and storing the information, the system needs no power supply and does not have to be connected to a live line by breaking it.     

Determination of Kinetic Parameters of Phase Transition on the Basis of DTA Measurements

A simple method of determination of kinetic parameters by analysis of DTA(t) function was developed for the case of systems undergoing transitions without mass change and when kinetic equation describing transition rate is known. The presented method also permits the determination of transition rate dα/dt (or α(t )) when the kinetic equation of transition is unknown. The developed method was tested using DTA data of crystallization of 2CaO×Al₂ O₃ ×1.95SiO₂ glass pure and doped with Cr³⁺ and Nd³⁺ . This revised version was published online in July 2006 with corrections to the Cover Date.     

Structures and Transport Properties of New Molecular Conductors Based on TMEO-ST-TTP

Several radical cation salts based on TMEO-ST-TTP (2-[4,5-bis(methylthio)-1,3-diselenol-2-ylidene]-5-(4,5-ethylendioxy-1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene) have been prepared. X-ray structure analyses of (TMEO-ST-TTP)₂X (X=PF₆, AsF₆, TaF₆) reveal that they have the so-called β-type array of donors with dimerized stacks. A tight-binding band calculation suggests that the present salts have a quasi-one-dimensional Fermi surface. On the other hand (TMEO-ST-TTP)Au(CN)₂ has strongly dimerized one-dimensional electronic structure. (TMEO-ST-TTP)₂X (X=PF₆, AsF₆, TaF₆) exhibit a high conductivity of σ_rt=10⁰-10¹S cm⁻¹, and retain metallic conductivity down to 4.2K, while the tetrahedral (ReO₄⁻) and linear (I₃⁻ and Au(CN)₂⁻) anions give semiconductors. Thermoelectric power of (TMEO-ST-TTP)₂PF₆ shows T-linear temperature dependence characteristic of a metal.     

Description of the Boiling Curve on the Basis of State Parameters of a Single Point

It is shown for the example of 40 substances that the normal boiling point can be used for approximately describing the entire boiling curve from the triple to critical point.     

Determination of the Kinetic Parameters of Chemical Reactions on the Basis of Non-Isothermal Measurements A critical review

A detailed analysis is presented of the applicability of several dependences commonly used for the determination of activation energies from non-isothermal measurements. Reactions proceeding according to different kinetic equations are simulated and the validity of the activation energy values obtained is discussed. The general conclusion is drawn that none of the examined dependences should be used to determine the activation energy. For a rough estimation of activation energy, the Kissinger equation can be applied according to Ockham's razor. This revised version was published online in August 2006 with corrections to the Cover Date.     

基于分布链修正的磁流变弹性体的物理模型

On the basis of distributed chains, the model of MR elastomer was revised. After the potential energy of a chain was analyzed using the local field method, a special function was used to describe the distribution of chains. Then the MR effect of distributed chains as well as the overall MR effect were studied. Concurrently, the effects of the curing magnetic field and the matrix were incorporated into the model of MR elastomer.     

Physicochemical Basis for the Creation of Liquid-Phase Sensor Materials Based on Tetraaryldithiaporphyrins

Russian Journal of General Chemistry - Basic properties of 5,10,15,20-tetraaryl-21-thia- and 5,10,15,20-tetraaryl-21,23-dithiaporphyrins in acetonitrile were examined spectrophotometrically. The...     

Molecular Lipophilicity Calculations of Chemically Heterogeneous Chemicals and Drugs on the Basis of Structural Similarity and Physicochemical Parameters

Abstract

QSARs based on molecular polarizability (α) and H-bond acceptor factors (∑C_a) as independent variables provided good predictability of octanol/water partition coefficients (P) for chemicals and drugs. However, for some molecules containing few functional groups, the calculated values deviated significantly from those observed. This approach gave good results when applied to a set of 138 chemicals and drugs previously studied by Mannhold and Dross who compared other methods to calculate log P values.

At the same time, three variations on a molecular similarity approach were pursued. In this study, a large training set with experimentally determined octanol/water partition coefficients (P) was searched for structures closely related to the compound-of-interest. The most successful of these variations took the mean log P value of few most closely related compounds after each was adjusted for differences between their and the compound-of-interest's polarizabilities (α) and H-bond acceptor capacities (∑C_a).     

Determination of High-Frequency Conductivity of NaCl and KCl Solutions on the Basis of Their Heating Rate by Electric Field with the Frequency of 27 MHz

Russian Journal of Electrochemistry - A method of determination of high-frequency conductivity in aqueous electrolyte solutions is suggested. It is based on measurement of the rate of simultaneous...     

利用溶解度参数选择有机溶剂提取土壤中多种有机氯农药

采用基团贡献法计算了提取溶剂（正己烷、二氯甲烷、正己烷—甲醇（体积比4：1)、正己烷—丙酮（体积比1：1)、正己烷—二氯甲烷(体积比1：1))和有机氯农药（o,p′—DDT,o．p′—DDE,o,p′—DDD,α—endosubn,endrin,HCB)的色散溶解度参数(δd)、极性溶解度参数(δp)和氢键溶解度参数(δh),运用溶解度参数的理论筛选有机溶剂提取江西红壤中多种有机氯农药：研究表明正己烷—甲醇（体积比4：1)和正己烷—丙酮（体积比1：1)是提取江西红壤中o,p′—DDT,o,p′—DDE,o,p′—DDD多种有机氯农药的最佳提取溶剂（回收率大于82％),对α—endosulfan,endrin,HCB的提取也能满足检测需要（回收率大于75％)。超声波提取的结果验证了溶解度参数预测的合理性。     

Rapid Estimation of Basis Set Error and Correlation Energy Based on Mulliken Charges and Mulliken Matrix with the Small 6-31g* Basis Set

Good, density functional quality (B3LYP/6-31G*) ground state total electronic energies have been approximated using single point Hartree–Fock-self consistent field (HF-SCF/6-31G*) total energies and Mulliken partial charges versus. Mulliken matrix (electrons assigned to atoms and atoms pairs from Mulliken population analysis). This is a development of our rapid estimation of basis set error and correlation energy from partial charges (REBECEP) method, published earlier (see references [21,22,30]. The development is as follows: (1) A larger set of atoms (H, C, N, O, F, Si, P and S) are considered as building blocks for closed shell, neutral, ground state molecules at their equlibrium geometry; (2) geometries near equilibrium geometry are also considered; (3) A larger set, containing 115 molecules, was used to fit REBECEP parameters; (4) most importantly, electrons belonging to chemical bonds (between atom pairs) are also considered (Mulliken matrix) in addition to the atoms (Mulliken charges), using more REBECEP parameters to fit and yielding a more flexible algorithm. With these parameters a rather accurate closed shell ground state electronic total energy can be obtained from a small basis set HF-SCF calculation in the vicinity of optimal geometry. The 3.3 kcal/mol root mean square deviation of REBECEP improves to 1.5 kcal/mol when using Mulliken matrix instead of Mulliken charges.     

Prediction of Solubility Parameters Based on the Explicit Expression of Statistical Thermodynamics

A robust and efficient procedure is presented for calculating the solubility parameter. An analytical equation for internal pressure is proposed. Through a simple relation reported by Verdier and Andersen (fluid phase equilibrium 231: 125–137, 2005), one can easily find the solubility parameter via our analytical equation for the internal pressure. Also, the radial distribution function (RDF) of a Lennard–Jones LJ (12, 6) fluid, proposed by Xu and Hu (fluid phase equilibrium 30: 221–228, 1986), has been employed to calculate the internal pressure of normal alkanes from methane to decane. Their solubility parameters were evaluated according to the calculated values of the internal pressure. A comparison between the experimental and the estimated values demonstrated a very good agreement between them.     

The Influence of Fluctuations on the Efficiency of Aerosol Particle Collection with Fibrous Filters

The influence of fluctuations on the filtration efficiency was studied. In the case of arbitrary random macroscopic inhomogeneities in the packing density and fluctuations in the filter surface form, the expressions were derived for the pressure drop and the penetration of aerosol particle, expressed via the correlation functions of fluctuating parameters. For the high degrees of cleaning, the probabilistic approach was developed, which takes into account the discreteness of the number of aerosol particles deposited on filter fibers.     

基于COSMO-SAC模型计算聚合物的溶解度参数

基于COSMO-SAC模型计算了几类聚合物膜材料与不同溶剂间的Flory-Huggins相互作用参数,利用溶解度参数与相互作用参数间的关系,分别通过线性拟合和最小二乘法获得了Hildebrand溶解度参数和Hansen溶解度参数。与文献值比较,Hildebrand溶解度参数计算结果的相对偏差区间为2.44%~17.31%,平均相对偏差为10.13%。当校正因子α=0.6时得到的Hansen溶解度参数相对偏差较小(6.64%),偏差区间为1.66%~13.60%;而α=1时得到的Hansen溶解度参数相对偏差较大(12.62%),偏差区间为5.56%~19.77%;α=0.6时得到的色散分量和偶极分量相对偏差较小,但氢键分量相对偏差较大。     

Tetrafluoroborate Selective Electrodes on the Basis of Cations with Delocalized Charge

Screening of active substances based on styryl and trimethine cyanine dyes was carried out to prepare tetrafluoroborate ion‐selective electrodes. Correlations between the nature of the organic cation (pK_a) and working pH ranges of the sensors were studied. New tetrafluoroborate‐selective PVC membrane electrodes based on an active substance formed by the ion pair of 2‐(n‐ethylcarbazol‐3)‐ethenyl‐1,3,3‐trimethyl‐3H‐indolium and 2‐[3‐(5,6‐dimethyl‐3‐nonyl‐1,3‐benzothiazol‐2(3H)‐ylidene)propenyl]‐5,6‐dimethyl‐3‐nonyl‐1,3‐benzothiazolium with tetrafluoroborate ion were developed. The electrodes are non‐sensitive to pH in the range of 2–8 and can be used for boron determination in acidic media of 6–7 mol L^?1 H₂SO₄. The developed sensor was successfully applied for the determination of B₂O₃ in CdS(Se) nanocrystal‐doped glasses.     

溶解性可调节的酶载体制备和固定化酶的研究

本文利用自由基沉淀聚合反应,合成了甲基丙烯酸-丙烯酰胺-顺丁烯二酸酐三元共聚物,测定了这些共聚物形成水不溶性的大分子氢键复合物的临界pH值.利用共聚物上的酸酐基团,直接进行了木瓜蛋白酶的固定化,得到了具有液相酶与固相酶两者优点的新型修饰酶。     

Determination of Spectrum-Structure Correlations Based on Integral Parameters of Mass Spectra

A general approach is proposed for the determination of spectrum-structure correlations and the investigation of relationships between the structure and reactivity of molecules in the gas phase using integral structural and mass spectral parameters (indices). These indices are generated taking into account all the observable parameters of a mass spectrum.     

High-Temperature Proton Conductors Based on Strontium and Barium Cerates: The Content, Interphase Exchange, and Diffusion of Hydrogen

The hydrogen content and hydrogen exchange kinetics of doped cerates of strontium and barium are studied in a reducing environment by the isotope balance and isotope exchange techniques. The measurements are performed at 500-840°C and hydrogen pressures of 2.7-16 gPa. The interphase exchange of hydrogen is found to occur at high speed via dissociative mechanisms. The effective activation energy for the hydrogen heteroexchange is determined. The diffusion coefficient for hydrogen in BaCe_0.95Nd_0.05O_3- is computed. The hydrogen content per formula unit appears to equal 0.48 ± 0.05 in SrCe_0.95Y_0.05O_3- and 0.60 ± 0.05 in BaCe_0.95Nd_0.05O_3- at 550 and 720°C, respectively, and a hydrogen pressure of 6.7 gPa. This is much greater than in an oxidizing environment, where the hydrogen content in an oxide is approximately proportional to the doping level of sublattice B. A possible explanation is connected with the presence of Ce³⁺ ions in the oxides or the dissolution hydrogen in a neutral form.     

The Effect of van der Waals' Forces on Aerosol Filtration with Fibrous Filters

The collection of aerosol particles with a fibrous filter under the effect of van der Waals' forces was considered with allowance for an electromagnetic retardation and a curvature of a fiber surface. To estimate van der Waals' forces, the method of pair summation of power potentials was used. The capture coefficient of inertialess particles of definite size was calculated. It was shown that as the interception parameter and the flow velocity decrease, the account for van der Waals' forces sharply increases the capture coefficient.