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Effect of Low Temperature on Hydration Performance of the Complex Binder of Silica Fume-Portland Cement

Journal of Wuhan University of Technology(Materials Science) 2014年第1期29卷 75-81页

作者：刘军 LI Yao YANG Yuanquan CUI Yunpeng Institute of Civil Engineering Dalian University of Technology School of Material Science and Engineering Shenyang Jianzhu University School of Material Science and Engineering Shenyang Ligong University

By analyzing the mechanical properties, composition of hydrates, content of Ca（OH）： and microstructure of the complex binder of silica fume-Portland cement, which cured at constant low temperatures（＋5--10 ℃）, the effect of different low temperatures on hydration performance of the complex binder at the age of 3, 7 days and 14 days was researched. Experimental results show that hydration processes of the complex binder can be restricted by low temperature. Reducing the curing temperature could cause compressive strength and flexural strength of the complex binder to decrease significantly. The gradient difference between strength diminishes, content of Ca（OH）2 in hydrates reduces, and compactness of the microstructure weakens. Therefore mixing with silica fume can modify various performance indicators of the complex blinder, but reducing the curing temperature restricts the pozzolanic activity of silicon fume.

关键词： low temperature strength content of Ca(OH)2 xrd analysis SEM

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Crystallization Kinetics of Lithium Aluminum Germanium Phosphate Glass by DSC Technique

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Journal of Wuhan University of Technology(Materials Science) 2012年第1期27卷 63-66页

作者：何坤 WANG Yanhang 祖成奎 LIU Yonghua ZHAO Huifeng HAN Bin CHENG Jiang Quartz and Special Glasses Institute China Building Materials AcademyBeijing 100024China

Abstract： The crystallization kinetics of Li20-A12O3-GeO2-P205 （LAGP） glass fabricated via the conventional melt-quenching method was studied by differential scanning calorimetry （DSC） under non- isothermal condition at different heating rates. The activation energy of glass transition Eg is 634.4 kJ/mol, indicating that LAGP glass is easy to crystallize at an elevated temperature. The activation energy of crystallization Eo and Avrami index n obtained from Matusita＇s model are 442.01 kJ/mol and 1.7, respectively. The value of n reveals that bulk crystallization predominates slightly over surface crystallization during crystallization process. LAGP glass-ceramics after different heat treatments have the same crystalline phases determined as major phase LiGe2（PO4）3, with A1PO4 and GeO2 as their impurity phases.

关键词： phosphate glass crystallization kinetics thermal stability xrd analysis

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Experiments on the effect of the pressure on the mineral transformation of coal ash under the different reaction atmosphere

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Frontiers of Chemical Science and Engineering 2010年第4期4卷 394-399页

作者： Nijie JING Qinhui WANG Zhongyang LUO Tao JIE Xiaomin LI Kefa CEN State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou 310027China

This paper investigated the effect of the pressures,reaction atmospheres and coal ash species on the ash fusibility with high-pressure thermogravimetric analysis(PTGA)apparatus and X-ray diffraction(xrd)*** specimen analyzed by xrd was observed for the mineral conversion and formation of new minerals with the pressures under different *** results indicate that the pressure restrains the transformation and decomposition of *** low-temperature minerals are still present under the elevated *** different reaction atmospheres have different effects on the formation of coal ash *** the N_(2)atmosphere,the present microcline may decrease the melting temperature of coal *** later,it transforms into sanidine at high pressure;thus,the melting temperature of coal ash may *** the CO_(2)atmosphere,the minerals such as microcline,lomonitite,geothite and illite are still present with the increase in pressure;this may reduce the melting *** under the H_(2)O atmosphere,there are magnetite and anorthoclase,which may produce the low-temperature eutectics decreasing the melting *** coal ash abundance in basic oxides or higher SiO_(2),Fe_(2)O_(3),K_(2)O and Na_(2)O has lower melting *** the ash sample with more SiO_(2)and Al_(2)O_(3)and less Fe_(2)O_(3)and basic oxides may lead to higher melting temperature.

关键词： ash fusibility xrd analysis PTGA lowtemperature eutectic

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xrd Doping Control of Light-Emitting cBN with a Large Size Mismatch between the Dopant and Intrinsic Atoms

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World Journal of Engineering and Technology 2016年第3期4卷 174-185页

作者： E. M. Shishonok V. G. Luhin J. W. Steeds Belarusian State University of Technology Minsk Republic of Belarus School of Physics University of Bristol Bristol UK

Cubic boron nitride (cBN) as the outstanding representative of the family of semiconducting wide bandgap nitrides and the closest analogue of diamond, is produced and investigated. xrd as method for doping control of cBN with impurities of large atomic sizes, is suggested. The larger an atomic size mismatch between doping and intrinsic atoms of a semiconductor’s crystal lattice, the stronger its response through own strains and distortions. The distortions are expected to be notable in the case of the smallest intrinsic atoms of cBN and diamond. The light-emitting cBN doped with various rare-earth elements (RE) in different concentrations under high pressure conditions is synthesized in form of the cBN: RE single phase micropowders. The micro-powders showed the discrete photoluminescence spectra in IR-, red and green spectral ranges which were attributed to the intra-electronic transitions of RE3+ ions located in cBN crystal lattice. The locations of the RE3+ ions in cBN crystal lattice are discussed. The data of xrd (CuKα) analysis of the cBN:RE micropowders are repre- sented. Extra-splits (as the additional ones to the α1-α2-splits on CuKα) of the cBN parent peaks in xrd patterns of the cBN: RE, are discovered and analyzed using appropriate computer programs. As established, crystal lattice of cBN due to the incorporation of RE3+ ions, represents a disordered solid solutions which are nonuniformly distorted in dependence on the ions’ size and their concentrations in cBN. Results of the present work can be useful to manufacture cBN with predictable functional properties, as well as for in situ doping control of cBN and diamond.

关键词： Cubic Boron Nitride High Pressure Rare Earth Element ?on Concentration Photoluminescence xrd analysis Crystalline Distortion

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