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An investigation on micro pore structures and the vapor pressure mechanism of explosive spalling of RPC exposed to high temperature

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Science China(Technological Sciences) 2013年第2期56卷 458-470页

作者： JU Yang LIU HongBin TIAN KaiPei LIU JinHui WANG Li GE ZhiShun State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology Beijing Key Laboratory of Fracture and Damage Mechanics of Rocks and Concrete China University of Mining and Technology School of Mechanics and Civil Engineering China University of Mining and Technology

Reactive powder concrete （RPC） is vulnerable to explosive spalling when exposed to high temperature. The characteristics of micro pore structure and vapor pressure of RPC are closely related to the thermal spalling. Applying mercury intrusion po- rosimetry （MIP） and scanning electron microscopy （SEM） techniques, the authors probed the characteristics of micro pore structures of plain RPC200 when heated from 20-350~C. The pore characteristics such as specific pore volume, threshold pore size and most probable pore size varying with temperatures were investigated. A vapor pressure kit was developed to measure the vapor pressure and its variation inside RPC200 at various temperatures. A thin-wall spherical pore model was proposed to ana- lyze the thermo-mechanical mechanism of spalling, by which the stresses varying with the vapor pressure q（T） and the character- istic size of wall （K） at any point of interest were determined. It is shown that the pore characteristics including specific pore volume, average pore size, threshold pore size and most probable pore size rise significantly with the increasing temperature. 200~C appears to be the threshold temperature above which the threshold pore size and the most probable pore size climb up dramatically. The increase in the specific pore volume results from the growth both in quantity and in volume of the transition pores and the capillary pores. The appearance of the explosive spalling in RPC200 is mainly attributed to being unable to form pathways in favor of releasing water steam in RPC and to thin-wall sphere domain where the vapor pressure governs the the rapid accumulation of high vapor pressures as well. The spalling is bounded through the pore model.

关键词： reactive powder concrete (RPC) high temperature spalling pore structure vapor pressure microstructures mercuryintrusion porosimetry (MIP)

vapor pressure measurement of lead and lead chlorides in FeO_T-CaO-SiO_2-Al_2O_3 system

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Transactions of Nonferrous Metals Society of China 2015年第8期25卷 2772-2780页

作者：张延玲 Eiki KASAI 北京科技大学钢铁冶金新技术国家重点实验室北京100083 Graduate School of Environmental Studies Tohoku University

vapor pressure of lead and lead chlorides from FeOT？CaO？SiO2？Al2O3 slag system was measured by using Knudsen effusion method. The results suggest that the vapor pressures of lead and lead chlorides increase with increasing temperature. For the slag systems without chlorine, the logarithm of vapor pressure （lnp） shows highly linear dependency on the reciprocal of temperature （1/T）, and higher vapor pressure is observed in the condition where more metallic lead vapor is formed. In this case, the vapor pressure of lead increases with increasing slag basicity （w（CaO）/w（SiO2））, increasing FeO content andw（Fe2＋）/w（Fe3＋） ratio. For the case of slag system with chlorine addition, the total pressures of PbCl2 and PbCl increase with decreasing basicity and FeO content of slag.

关键词：金属Pb vapor pressure Knudsen effusion method metallic Pb lead chlorides smelting process

Effects of vapor pressure and Super-Hydrophobic Nanocomposite Coating on Microelectronics Reliability

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Engineering 2015年第3期1卷 384-390页

作者： Xuejun Fan Liangbiao Chen C.P.Wong Hsing-Wei Chu G.Q.Zhang Department of Mechanical Engineering Lamar University State Key Laboratory of Solid State Lighting School of Materials Science and Engineering Georgia Tech Delft University of Technology Institute of Semiconductors Chinese Academy of Sciences

Modeling vapor pressure is crucial for studying the moisture reliability of microelectronics, as high vapor pressure can cause device failures in environments with high temperature and humidity. To minimize the impact of vapor pressure, a super-hydrophobic(SH) coating can be applied on the exterior surface of devices in order to prevent moisture penetration. The underlying mechanism of SH coating for enhancing device reliability, however, is still not fully understood. In this paper, we present several existing theories for predicting vapor pressure within microelectronic materials. In addition, we discuss the mechanism and effectiveness of SH coating in preventing water vapor from entering a device, based on experimental results. Two theoretical models, a micro-mechanics-based whole-field vapor pressure model and a convection-diffusion model, are described for predicting vapor pressure. Both methods have been successfully used to explain experimental results on uncoated samples. However, when a device was coated with an SH nanocomposite, weight gain was still observed, likely due to vapor penetration through the SH surface. This phenomenon may cast doubt on the effectiveness of SH coatings in microelectronic devices. Based on current theories and the available experimental results, we conclude that it is necessary to develop a new theory to understand how water vapor penetrates through SH coatings and impacts the materials underneath. Such a theory could greatly improve microelectronics reliability.

关键词： vapor pressure moisture semiconductor reliability microelectromechanical systems (MEMS) superhydrophobic nanocomposite coating

vapor pressure Measurement and Correlation of 2-Methyl-Butanol Acetate Containing Calcium Chloride

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Chinese Journal of Chemical Engineering 2011年第1期19卷 97-100页

作者：刘其松姚舜朱堂峰曾红宋航 School of Chemical Engineering Sichuan University Chengdu 610065 China

The CaCl2 solubility in 2-methyl-butanol acetate and the vapor pressure of 2-methyl-butanol acetate containing CaCl2 were measured in the range of 90-135°C and from very low salt concentration to *** experimental data were correlated with two equations,a modified Antoine equation with the dissolved salt taken into account and a nonrandom two liquid-electrolyte（e-NRTL）*** models are in good agreement with the experimental *** study provides essential physical data for further investigation of vapor-liquid equilibrium system containing salt.

关键词： vapor pressure 2-methyl-butanol acetate calcium chloride Antoine equation e-NRTL

vapor pressure Measurement of Water+1,3-Dimethylimidazolium Tetrafluoroborate System

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Chinese Journal of Chemical Engineering 2011年第3期19卷 473-477页

作者：武向红李静范丽华郑丹星董丽 College of Chemical Engineering Beijing University of Chemical Technology

In absorption cycles,ionic liquid(IL)1,3-dimethylimidazolium tetrafluoroborate([Dmim]BF4)may be a promising absorbent of working pair using water as *** vapor pressures of[Dmim]BF4 aqueous solution were measured with the boiling-point method in the temperature range from 312.25 to 403.60 K and in the mass concentration range of 65%to 90%of[Dmim]*** experimental data were correlated with an Antoine-type equation and the Non-Random Two-Liquid(NRTL)model,and the average absolute deviations between the experimental and calculated values were 1.06%and 1.15%,*** the[Dmim]BF4 aqueous solution,the experimental vapor pressures show negative deviations from the calculated data with Raoult's *** higher mass concentration of the IL,the deviation is more *** addition,the vapor pressures,the hydrophilicity and the solubility of[Dmim]BF4 aqueous solutions were compared with those of[Dmim]Cl aqueous solutions and [Bmim]BF4 aqueous solutions at IL-mole fraction of 0.20.

关键词： ionic liquid 1 3-dimethylimidazolium tetrafluoroborate vapor pressure absorption cycle working pair

vapor pressure measurement and correlation of acetonitrile + 1-butyl-3-methylimidazolium chloride, + 1-butyl-3-methylimidazolium tetrafluoroborate, and + 1-hexyl-3-methylimidazolium chloride

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Chinese Journal of Chemical Engineering 2015年第2期23卷 412-416页

作者：杨青陈科侠何昌春彭昌军刘洪来 State Key Laboratory of Chemical Engineering and Department of Chemistry East China University of Science and Technology

vapor pressures were measured for acetonitrile+1-butyl-3-methylimidazolium chloride([C4mim][Cl]),+1-butyl-3-methylimidazolium tetrafluoroborate([C4mim][BF4])and+1-hexyl-3-methylimidazolium chloride([C6mim][Cl])at temperatures of 313 to 353 K by a quasi-static *** experimental data for the binary systems were correlated by the non-random two liquid(NRTL)equation with an average absolute relative deviation(AARD)of within 1.84%.The results indicate that the three ionic liquids(ILs)can result in a negative deviation from the Raoult's law for the binary solutions containing acetonitrile,and the affinity between ILs and acetonitrile molecules follows the order[C4mim][BF4]+acetonitrile N[C4mim][Cl]+acetonitrile N[C6mim][Cl]+acetonitrile.

关键词： Acetonitrile Ionic liquid vapor pressure Non-random two liquid

Experimental Study on vapor pressure of HFC-134a

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Journal of Thermal Science 1992年第2期1卷 80-82页

作者： Ming－ShanZhu Yi－DongFu 等 ThermalEngineeringDepartment TsinghuaUniersityBeijing100084China ThermalEngineeringDepartment Tsing

As part of the study on thermophysical properties of HFC-134a,this paper concerns itself with vapor pressure of HFC-134a in the temperature range of 279.15K to 365.15K.A total of 43 measurement data were measured during the experiment which was conducted on a high precision PVTx test apparatus designed by the authors with slight *** of temperature was ±10mK and of pressure was ±*** of sample was either 99.95wt% or 99.98wt%.Data resulting from this experiment matched closely with the newest data published *** to our proposed equation for calculating vapor pressure of HFC-134a, the RMS deviation of experimental data was only 0.0531%,showing relatively high precision.

关键词： vapor pressure HFC-134a CFC's alternative thermophysical properties.

Measurement and Prediction of vapor pressure for H20 ＋ CHaOH] C2HsOH ＋ [BMIM][DBP] Ternary Working Fluids

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Chinese Journal of Chemical Engineering 2013年第8期21卷 886-893页

作者：张晓冬胡大鹏赵宗昌 School of Chemical Machinery Dalian University of Technology School of Chemical Engineering Dalian University of Technology

The ionic liquid, 1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][DBP]) was prepared and the vapor pressures of three set of binary solutions H2O(1)/CH3OH(1)/C2H5OH(1) + [BMIM][DBP](2) were measured at different temperature and in the ILs mole fraction range from 0.1 to 0.6 with a static equilibrium apparatus. The measured vapor pressures were correlated with Non-Random Two Liquid (NRTL) activity coefficient model and the average relative deviations (ARD) between experimental and correlated vapor pressures for these binary solutions were 3.19%, 2.42% and 2.95%, respectively. Then, the vapor pressures of two set of ternary solutions H2O(1) + CH3OH(2)/C2H5OH(2) + [BMIM][DBP](3) were measured with an inclined boiling apparatus and further predicted with NRTL activity coefficient model based on the binary interaction parameters coming from fitting the vapor pressures of the binary solutions. The results indicated that the ternary solutions containing [BMIM][DBP] were shown a strong negative deviation from Raoult's Law when the mole fraction of [BMIM][DBP] was larger than 0.2, which meant that ternary solutions could absorb the refrigerant vapors at the same or below solution temperature. Meanwhile, the average relative deviations between experimental and predicted vapor pressures for ternary solutions were 2.92% and 3.06%, respectively. Consequently, the NRTL active coefficient model used for non-electrolyte solutions was still valid for predicting vapor-liquid equilibrium of binary or ternary solutions containing ILs.

关键词： ionic liquid ternary working fluids vapor pressure NRTL model absorption refrigeration

Important Parameter:vapor pressure of Extracting Solvent in Headspace Liquid Phase Micro-extraction Technique

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Important Parameter:Vapor Pressure of Extracting Solvent in ...