层状过渡金属硫代亚磷酸盐及其夹层化合物

层状过渡金属硫代亚磷酸盐(MPS3)及其夹层物由于所表现出的特殊的固体物理化学性质而受到关注。本文将主要介绍层状过渡金属硫代亚磷酸盐及其夹层物的合成、结构及固体物理性质等方面的研究状况及进展。

Physical Properties and Electrochemical Performance of Solid K_2FeO_4 Samples Prepared by Ex-situ and in-situ Electrochemical Methods

K2FeO4 powders were synthesized by the ex-situ and in-situ electrochemical methods, respectively, and characterized by infrared spectrum （IR）, scanning electron microscopy （SEM）, X-ray powder diffraction （XRD） and BET. Their electrochemical performances were investigated by means of galvanostatic discharge and electrochemi-cal impedance spectroscopy （EIS）. The results of physical characterization showed that the two samples have simi-lar structural features, but their surface morphologies and oriented growth of the crystals are different, which results in smaller specific surface area and lower solubility of the ex-situ electrosynthesized K2FeO4 sample. The results of discharge experiments indicated that the ex-situ electrosythesized K2FeO4 electrode has much larger discharge ca-pacity and lower electrode polarization than the in-situ electrosynthesized K2FeO4 electrode. It was found from the results of EIS that lower electrochemical polarization might be responsible for the improvement on the discharge performance of the ex-situ electrosynthesized K2FeO4 electrode.

Physical properties of solid fuel briquettes from bituminous coal waste and biomass

Biomass and bituminous coal fines from four different coalfields were used to produce fuel briquettes. Two physical properties of briquettes, water resistance index and compressive strength were analyzed. The influence of type and quantity of biomass on physical properties was also studied. The results reveal that depending on the mineral content of the coal, the physical properties of the briquettes differ noticeably. The comparison of briquettes with and without biomass showed that the presence of the beet pulp increased CS in all types of coal samples. Samples containing beet pulp had better physical properties than sawdust. Mezino II coal briquettes had highest CS and WRI than the other ones. Calorific value of biomass/Mezino lI coal briquettes was lessened in comparison with raw coal, but it remained in an acceptable range.

Measurement and Correlation of Solid Drugs Solubility in Supercritical Systems

A dynamic experimental set-up was utilized to measure ibuprofen solubility in supercritical CO2 at the pressure range of 8-13 MPa and the temperatures of 308, 313 and 318 K. Mole fraction values varied from 0.015＆#215;10^-3 to 3.261＆#215;10^-3 and correlated by using seven different semi empirical equations of state （Bartle, Modi-fied Bartle, Mendez-Teja, Modified Mendez-Teja, Kumar-Johnson, Sung-shim and Gordillo） as well as seven cubic equations of state （van der Waals, Redlich-Kwong, Soave-Redlich-Kwong, Peng-Robinson, Stryjek-Vera, Patel-Teja-Valderana and Pazuki）. Single and twin-parametric van der Walls mixing rules （vdW1, vdW2） were ap-plied in order to estimate the supercritical solution properties. The physicochemical properties were also obtained using Joback, Lydersen and Ambrose methods. Absolute average relatives deviation （AARD） were calculated and compared for all the correlating systems. Results showed that among the cubic equations of state （EOSs） the Pazuki equation （AARD=19.85% using vdW1 and AARD=8.79% using vdW2） and SRK equation （AARD=19.20%using vdW1 and AARD=10.03%using vdW2） predicted the ibuprofen solubility in supercritical CO2 with the least error in comparison to the others. Among the semi-empirical EOSs the most desirable deviation （AARD〈10%） was obtained by using Modified Bartle and Modified Mendez-Teja equations in all the studied temperatures.

Characterization of semi-coke generated by coal-based direct reduction process of siderite

Solid wastes derived from metallurgical industries pose a significant threat to environment. The utilization and disposal of these solid wastes are the major concern in the world. Semi-coke generated in coal-based direct reduction process of iron ore is a by-product and its suitable utilization is not available so far. In order to handle it properly, the characteristics of this by-product were comprehensively investigated. A series of analysis methods were used to demonstrate its mineral compositions, petrography and physico-chemical properties. The results reveal that the semi-coke has poor washability. The fixed carbon content of semi-coke reaches 76.11% and the gross calorific value is 28.10 MJ/kg, both of which are similar to those of traditional sinter coke breeze. Also, semi-coke ash possesses lower content of SiO2, Al2O3, S and higher content of CaO and MgO, which could improve the strength of sinter ore when partially substituting for coke breeze in sintering. Semi-coke features well-development porous structure and higher reaction activity, which predicts that the sintering speed could be elevated to some extent when employing it as a partial replacement of coke breeze, so the studies further suggest that the potential adverse effect of the high reactivity on sintering process could be weakened by adequately coarsening the semi-coke's particle size.

Research Characterized the Physical Properties of Recycled Aggregate of Civil Construction Wastes

One of the big problems of the urban centres of the cities in Brazil is the growth of the generation of the Civil Construction Waste （CCW）. A disturbing concern for the public and private sectors is to find proper disposal of Urban Solid Waste （USW） in large cities, since suitable dumping sites for this waste are increasingly scarce due to the spread and development of large urban centres. In general, recycling is currently one of the procedures most studied by researchers for disposal of such waste. In this context and aiming a new application for recycled CCW aggregates, the research characterized the physical properties of the material to use in fill compaction piles in soil improvement. The analysis shows results from laboratorial tests executed in CCW recycled samples, which came from works in different construction stages from Recife-PE, and natural aggregate, adopted as a reference. Characterization tests were performed with samples CCW recycled CLue aggregates and samples of natural fine aggregate （stone powder）. The results of characterization tests showed similarities between the CCW samples tested and the reference samples, indicating that the civil construction wastes has potcntial use as material for consolidation piles in foundation works.

Estimation of thermophysical properties of solid propellants based on particle packing model

A method for the estimation of thermophysical properties of two-and multi-phase solid propellants is proposed in this paper.The theoretical solutions for thermal conductivity and specific heat of a homogeneous solid propellant cell in the transient thermal conductivity process are deduced on the condition that one boundary of the cell is heated while others are adiabatic.A homogenization theory and the finite element method are employed to compute the mean temperature and heat flux of a representative volume element(RVE).According to the mean results and the theoretical solutions,the effective thermal conductivity and specific heat of solid propellant can be estimated.A packing algorithm,considering the solid particles(ammonium perchlorate(AP)or aluminum)as spheres or discs,is used to match the size distribution and volume fraction of solid propellants,and some mesoscopic models of two-phase and three-phase solid propellants are established.According to the estimation theory proposed in this paper,the effective thermal conductivity and specific heat of solid propellants are predicted.The effect of AP or Al volume fraction is also discussed in this paper.

BOUNDARY CONTROL OF TWO PDE'S SEPARATED BY INTERFACE CONDITIONS

This paper discusses the null boundary controllability of two PDE's,modeling a compositesolid with different physical properties in each layer.Interface conditions are imposed.

Density-functional-theory formulation of classical and quantum Hooke's law

A fundamental property of solid materials is their stress state. Stress state of a solid or thin film material has profound effects on its thermodynamic stability and physical and chemical properties. The classical mechanical stress （σ^M） originates from lat- tice strain （e）, following Hooke＇s law： σ^M=Cε, where C is elastic constant matrix. Recently, a new concept of quantum electronic stress （o-QE） is introduced to elucidate the extrinsic electronic effects on the stress state of solids and thin films, which follows a quantum analog of classical Hooke＇s law： ~QE=E（An）, where E is the deformation potential of electronic states and An is the variation of electron density. Here, we present mathematical derivation of both the classical and quantum Hooke＇s law from density functional theory. We further discuss the physical origin of quantum electronic stress, arising purely from electronic excitation and perturbation in the absence of lattice strain （g=0）, and its relation to the degeneracy pressure of electrons in solid and their interaction with the lattice.