Influence of eutectic addition on the electrical conductivity of Li2O:B2O3 system

Addition of three eutectics, Li₂SO₄:Li₂CO₃, 3Li₂O·Nb₂O₅:LiNbO₃ and AgI:Ag₂SO₄ has been tried in the Li₂O:B₂O₃ glass system. The electrical conductivity increases with the addition of eutectic. The amount of lithium fraction and the melting point of the eutectic govern the conductivity.     

Tensile deformation behavior and mechanical properties of a bulk cast Al_(0.9) CoFeNi_2 eutectic high-entropy alloy

In this study,a new Al0.9CoFeNi2 eutectic high entropy alloy(EHEA) was designed,and the microstructures as well as the deformation behavior were investigated.The bulk cast Al0.9CoFeNi2 EHEA exhibited an order face-centered cubic FCC(L12) and an order body-centered cubic(B2) dual-phase lamellar eutectic microstructure.The volume fractions of FCC(L12) and B2 phases are measured to be 60 % and 40 %,respectively.The combination of the soft and ductile FCC(L12) phase together with the hard B2 phase resulted in superior strength of 1005 MPa and ductility as high as 6.2 % in tension at room temperature.The Al0.9CoFeNi2 EHEA exhibited obvious three-stage work hardening characteristics and high workhardening ability.The evolving dislocation substructure s during uniaxial tensile deformation found that planar slip dominates in both FCC(L12) and B2 phases,and the FCC(L12) phase is easier to deform than the B2 phase.The post-deformation transmission electron microscopy revealed that the sub-structural evolution of the FCC(L12) phase is from planar dislocations to bending dislocations,high-density dislocations,dislocation network,and then to dislocation walls,and Taylor lattices,while the sub-structural evolution of the B2 phase is from a very small number of short dislocations to a number of planar dislocations.Moreover,obvious ductile fracture in the FCC(L12) phase and a brittle-like fracture in the B2 phase were observed on the fracture surface of the Al0.9CoFeNi2 EHEA.The re search results provide some insight into the microstructure-property relationship.     

Effect of energy nonequipartition on the transport properties in a granular mixture

The Boltzmann kinetic theory is used to analyze the effect of energy nonequipartition on the pressure and the shear viscosity of a granular binary mixture under simple shear flow. Theory and Monte Carlo simulations show that both quantities exhibit a non–monotonic behaviour with the mass ratio in contrast to the predictions made from previous theories based on the equipartition assumption. Our results agree qualitatively well with recent molecular dynamics simulations performed by Alam and Luding [Granular Matter 4, 139 (2002)]. The authors acknowledge partial support from the MCYT (Spain) through Grants No. BFM2001-0718 and ESP2003-02859.     

Phase diagram and thermochemical properties of organic eutectic in a monotectic system

The phase diagram of a binary organic system involving diphenyl and succinonitrile shows the formation of a eutectic (0·968 mole fraction of succinonitrile) and a monotectic (0·074 mole fraction of succinonitrile) with a large miscibility gap in the system, the upper consolute temperature being 53·5°C above the monotectic horizontal. From the enthalpy of fusion of the pure components, the eutectic and the monotectic, determined by the DSC method, the enthalpy of mixing, Jackson’s roughness parameter, interfacial energy, size of the critical nucleus and excess thermodynamic functions were calculated.     

一种新型三元体系磷酸钙骨水泥的制备与性能优化

制备了一种新型磷酸氢钙-部分结晶磷酸钙-磷酸四钙三元体系骨水泥,采用正交试验优化骨水泥组分以提高材料的性能。通过力学性能测试、X射线衍射分析、扫描电镜观察以及反应过程水化放热测定,对比研究了所制备的三元体系骨水泥材料的水化过程和物相组成。结果表明所添加活性磷酸四钙参与水化反应较慢,延长了骨水泥的凝结时间,拓展了后期水化效应,使得反应后期水化进程得以延续,硬化体更加密实,孔隙率降低,抗压强度增加50%;同时反应放热峰值显著降低40%,水化过程总放热量基本不变,有利于骨水泥在临床应用。     

消能伸臂体系减震性能的参数变异性影响分析

为研究结构参数变异性对消能伸臂体系减震性能的影响,推导了该体系的有限元振动方程,同时提出地震响应简化分析的"Maxwell型阻尼器计算法",并结合Gauss-Hermite降维算法分析了确定性激励、随机地震激励作用的参数变异影响情况.结果表明:Gauss-Hermite降维算法既能保证精度又能提高计算效率;确定性激励时...     

The nature of the ordering of atoms in a melt and the surface properties of simple eutectic systems

Using the models reconstructed from the experimental structure factor curves by the reverse Monte-Carlo and Voronoy-Delaunay methods the local atomic structures of the Sn-Ge, Ag-Ge, and Ni-C simple eutectic systems has been analyzed. It has been found that the nature of the atom ordering in melts is responsible not only for the melt bulk properties, but for its surface properties (surface tension, wetting) as well. Clusters that form from atoms of the same sort in melts and whose binding energy inside the clusters exceeds the binding energy between the atoms of a solvent and a cluster, exhibit the surface activity in the melt, which explains the extremes in isotherms of the density and surface tension of the melts. Clusters with a chemical ordering of atoms patterned after the Me₃C electronic compound revealed in the Ni-C and Ag-Ge systems indicate that the equilibrium phase diagrams of these systems at high pressures transform from diagrams of a simple eutectic type to diagrams with a compound, i.e. an increase in pressure contributes to the metallization of bonds in a melt.     

The Influence of Drug Solubility and Particle Size on the Pellet Formulation in a Rotoprocessor

ABSTRACT

Pellets containing drugs of different properties were prepared in a Rotoprocessor in order to study changes in the formulation process and resulting pellet characteristics. Diltiazem hydrochloride, diclofenac sodium, and theophylline were chosen as model drugs. Pellet size distribution, sphericity, density, hardness, friability, and repose angle were determined using standard methods. The amount of water as a wetting agent necessary for successful pellet formulation was observed for each sample and changed depending on drug solubility, concentration, and particle size. The pelletization of freely soluble diltiazem hydrochloride required 24.8–23.1% of the wetting agent and its amount decreased as the drug concentration increased. The demand for water in the formulation of theophylline pellets was 31.0–34.4% and it increased with increasing drug concentration. The pellet samples containing both drugs were easy to prepare. However, the cohesion of micronized diclofenac sodium particles negatively influenced both the pellet size distribution and the formulation process itself. When the drug concentration exceeded 40%, it was not possible to produce pellets of an appropriate size and the process was not reproducible.     

主链含柔性亚甲基苯并二噁唑类聚合物的合成及性能研究

设计并合成了一系列含有苯并噁唑环和不同CH2链长的刚、柔间隔聚亚甲基苯并二噁唑（PBOCx）聚合物，并对它们进行了结构表征，同时对聚合物的溶解性能和热性能进行了探讨．研究表明，在主链上引入亚甲基结构可以在一定程度上提高聚合物的溶解性，其中PBOC4显示了良好的溶解性能，但随着亚甲基数目的增加，聚合物的溶解性能有下降趋势；虽然有柔性链段的引入，分解温度降低，但是PBOCx仍具有很高的热分解温度，在450℃以下表现出良好的热稳定性．     

Drug solubility in phospholipid carrier as a predictive parameter for drug recovery in microparticles produced by the aerosol solvent extraction system (ASES) process

The solubility of various drugs in a constant ratio of phosphatidylcholine-cholesterol carrier were studied to investigate their influence on drug recovery in drug-lipid microparticles produced by the aerosol solvent extraction system (ASES) process. Solubility of the drugs in such lipid carrier were determined by using differential scanning calorimetry and confirmed by X-ray powder diffraction study. The results showed that drug possessing relatively high solubility in the lipid carrier used could lead to a higher amount of drug recovered in the drug-lipid microparticles produced. However, too high amount of dissolved drug imposed an adverse effect on the solidification of the lipid carrier during ASES processing, which led to partial film formation in the production column and hence a lower yield of microparticles. Such adverse effect was not the case for the drugs with low solubility in the carrier but there was an incomplete recovery of drug in the produced microparticles due to the partial extraction by the supercritical gas instead. The maximum amount of drug recovered in the ASES-prepared microparticles was found to correlate to the solubility of drug in the lipid carrier so that it might be utilized as a predictive parameter for determining the amount of drug to be incorporated into the microparticles.     

Influence of the heat flux in mixture boiling: experiments and correlations

Heat transfer at nucleate pool boiling of the binary and ternary refrigerant mixtures R404A, R407C and R507 at the outside of a horizontal tube with emery ground surface has been investigated in a wide range of pressures and heat fluxes. Together with experimental data of Bednar and Bier for wide boiling ethane/n-butane mixtures, the results of these comparatively narrow boiling mixtures are used to investigate the influence of heat flux q on the heat transfer coefficient as predicted by various correlations for nucleate boiling of mixtures. At comparatively high saturation pressures with experimental -values markedly smaller than the molar average of the pure components, the ,q-relationships predicted differ significantly from the experimental, particularly for wide boiling mixtures.     

Influence of fly ash as a cement addition on the hardened properties of recycled aggregate concrete

The effects of the use of Class F fly ash as a cement addition on the hardened properties of recycled aggregate concrete were determined. In this study, four series of concrete mixtures were prepared with water-to-cement (w/c) ratios of 0.55, 0.50, 0.45 and 0.40. The recycled aggregate was used as 0%, 20%, 50% and 100% replacements of coarse natural aggregate. Furthermore, fly ash was employed as 0% and 25% addition of cement. Although the use of recycled aggregate had a negative effect on the mechanical properties of concrete, it was found that the addition of fly ash was able to mitigate this detrimental effect. Also, the addition of fly ash reduced the drying shrinkage and enhanced the resistance to chloride ion penetration of concrete prepared with recycled aggregate. Moreover, it was found that the drying shrinkage and chloride ion penetration decreased as the compressive strength increased. Compared with the results of our previous study, the present study has quantified the advantages of using fly ash as an additional cementitious material in recycled aggregate concrete over the use of fly use as a replacement of cement.     

聚醚砜四元制膜液体系的相图计算

以Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ理论为基础，对ＰＥＳ－ＰＧ－ＮＭＰ＿Ｈ２Ｏ＿）聚醚砜丙二醇－Ｎ－甲基－２－哟咯烷酮水）四元制液体系的相图进行了计算，利用三元相图考察Ｈ２Ｏ和ＰＧ对液－液相分离的影响，在三元的理论的基础上提出了低分子量添加剂的卤元改性Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ理论，并提出了一种获得四元相图的方法，利用四元相图能较争地描述四元体系，利用改性的四元理论，能了地理解该种体系的液－液相分离行为。     

Study and improvement of interfacial properties in a MIS structure based on p-type InP

Indium phosphide is one of the most promising candidates among the available III-V semiconducting compounds for the development of MIS technology. This is based on the availability of InP substrates and the relatively large band gap. Before the deposition of the insulator, the InP surface must be treated and well passivated (Surf Interface Anal 20 (1993) 803; J Appl Phys 67 (1990) 4173). We have shown that a InSb buffer layer can reduce the phosphorus atom migration and the concentration of defects at the interface. We have studied and characterized electrically two series of substrates using p-type InP, the first one with thin and the second with thick insulator films. The results obtained show clearly the reduction of the defects in the thicker structures protected by the InSb buffer layer.     

水流开关在空调系统中的应用及改进

水流开关在冷水机组和空调工程的水系统中应用广泛,它能保证空调系统安全、高效地运行。通常水流开关在应用时只能定性地保证空调系统的安全和高效运行,而不能定量、准确地设定水流开关闭合和断开时的流量值。本文根据空调系统制冷量的不同,设计与之相匹配的水流开关,并利用简易水流量测定系统,对水流开关的闭合和断开流量值进行测定,实现对水流开关应用的改进。     

Influence of potassium and fluorine on the formation and properties of the high-temperature 2223 phase in a (Bi, Pb)-Sr-Ca-Cu-O system

An investigation was made of how the partial replacement of oxygen with fluorine and of strontium with potassium influences the formation and properties of the superconducting phases in a (Bi,Pb)-Sr-Ca-Cu-O system. It was established that simultaneous anion-cation substitutions have a positive influence, speeding up the formation of the 2223 high-temperature phase. Pis’ma Zh. Tekh. Fiz. 24, 8–15 (May 26, 1998     

Enhanced structural and optical properties of ZnO nanopowder with tailored visible luminescence as a function of sodium hydroxide to zinc sulfate mass ratio

ZnO nanopowders of tailored particle sizes were synthesized using a simple wet chemical method, by controlling the mass ratio of the precursors. The physical properties were investigated as a function of OH^?/Zn²⁺ mass ratio (x). The structural properties of the synthesized nanoparticles (NPs) are studied using X-ray diffraction (XRD). XRD patterns show pure wurtzite structure. Microstructural parameters dependence on x ratio was studied based on Williamson-Hall model. We notice an increase in crystallite size (17–24?nm) and a decrease in strain values when the x ratio increases (0.5–1.4). The best crystallinity corresponds to the higher mass ratio. Indeed, for x?=?1.4 we obtain the largest crystallite size, the lowest strain and stacking faults. The TEM images support the XRD results. Raman spectra confirm the purity of the synthesized ZnO powder. Furthermore, the optical properties were examined by UV–vis and Photoluminescence as a function of precursor’s ratio. Absorption data show a band gap red-shift of the ZnO-NPs with increase in particle’s size. Moreover, we found that the ZnO-NPs luminescence in the visible range can be engineered by changes of x ratio. This constitutes an advantage for the use of ZnO-NPs in different wavelength areas in optoelectronic applications covering UV-Blue-Green domain for the LED design, sensors…