This paper presents the findings on thermal expansion behavior of slaked lime doped rice husk silica(RHS)refractory monitored between 25℃and 1500℃.It also reports the phase transition analysis within the temperature...This paper presents the findings on thermal expansion behavior of slaked lime doped rice husk silica(RHS)refractory monitored between 25℃and 1500℃.It also reports the phase transition analysis within the temperature range of 850-1450℃.A sudden expansion of 0.7%noticed at 220℃is due to the transformation ofα-cristobalite toβ-cristobalite.The highest expansion(0.85%)reached within the temperature range of 650-850℃,remains almost constant for the investigated temperature range,and is not high enough to cause macro cracks in the refractory.The phase transition order is similar to those reported for quartzite refractory after 600℃,though the crystallization temperature is lowered due to the presence of the dopant.Modulus of rupture,apparent porosity,bulk density,refractoriness and reheat change are reported and their results meet with the standards qualifying them for use in coke ovens.展开更多
A series of hydrogenated silicon thin films were prepared by the radio frequency plasma enhanced chemical vapor deposition method (RF-PECVD) with various si-lane concentrations. The influence of silane concentration o...A series of hydrogenated silicon thin films were prepared by the radio frequency plasma enhanced chemical vapor deposition method (RF-PECVD) with various si-lane concentrations. The influence of silane concentration on structural and elec-trical characteristics of these films was investigated to study the phase transition region from amorphous to microcrystalline phase. At the same time,optical emis-sion spectra (OES) from the plasma during the deposition process were monitored to get information about the plasma properties,Raman spectra were measured to study the structural characteristics of the deposited films. The combinatorial analysis of OES and Raman spectra results demonstrated that the OES can be used as a fast method to diagnose phase transition from amorphous to microcrystalline silicon. At last the physical mechanism,why both OES and Raman can be used to diagnose the phase transition,was analyzed theoretically.展开更多
The quasi-solid-liquid phase transition exists widely in different fields,and attracts more attention due to its instinctive mechanism.The structure of force chains is an important factor to describe the phase transit...The quasi-solid-liquid phase transition exists widely in different fields,and attracts more attention due to its instinctive mechanism.The structure of force chains is an important factor to describe the phase transition properties.In this study,the discrete element model(DEM) is adopted to simulate a simple granular shear flow with period boundary condition on micro scale.The quasi-solid-liquid phase transition is obtained under various volume fractions and shear rates.Based on the DEM results,the probability distribution functions of the inter-particle contact force are obtained in different shear flow phases.The normal,tangential and total contact forces have the same distributions.The distribution can be fitted as the exponential function for the liquid-like phase,and as the Weibull function for the solid-like phase.To describe the progressive evolution of the force distribution in phase transition,we use the Weibull function and Corwin-Ngan function,respectively.Both of them can determine the probability distributions in different phases and the Weibull function shows more reasonable results.Finally,the force distributions are discussed to explain the characteristics of the force chain in the phase transition of granular shear flow.The distribution of the contact force is an indicator to determine the flow phase of granular materials.With the discussions on the statistical properties of the force chain,the phase transition of granular matter can be well understood.展开更多
基金This work was supported in part by the Malaysian Ministry of Science,Technology&Innovation(MOSTI)E-Science Fund(Project Code 03-02-02-SF0089)and UTP graduate assistantship scheme.
文摘This paper presents the findings on thermal expansion behavior of slaked lime doped rice husk silica(RHS)refractory monitored between 25℃and 1500℃.It also reports the phase transition analysis within the temperature range of 850-1450℃.A sudden expansion of 0.7%noticed at 220℃is due to the transformation ofα-cristobalite toβ-cristobalite.The highest expansion(0.85%)reached within the temperature range of 650-850℃,remains almost constant for the investigated temperature range,and is not high enough to cause macro cracks in the refractory.The phase transition order is similar to those reported for quartzite refractory after 600℃,though the crystallization temperature is lowered due to the presence of the dopant.Modulus of rupture,apparent porosity,bulk density,refractoriness and reheat change are reported and their results meet with the standards qualifying them for use in coke ovens.
基金Supported by the National Basic Research Program of China (Grant Nos. 2006CB202602 and 2006CB202603)
文摘A series of hydrogenated silicon thin films were prepared by the radio frequency plasma enhanced chemical vapor deposition method (RF-PECVD) with various si-lane concentrations. The influence of silane concentration on structural and elec-trical characteristics of these films was investigated to study the phase transition region from amorphous to microcrystalline phase. At the same time,optical emis-sion spectra (OES) from the plasma during the deposition process were monitored to get information about the plasma properties,Raman spectra were measured to study the structural characteristics of the deposited films. The combinatorial analysis of OES and Raman spectra results demonstrated that the OES can be used as a fast method to diagnose phase transition from amorphous to microcrystalline silicon. At last the physical mechanism,why both OES and Raman can be used to diagnose the phase transition,was analyzed theoretically.
基金supported by the National Basic Research Program of China (Grant No. 2010CB731502)the Fundamental Research Funds forthe Central Universities (Grant No. DUT12YQ02)
文摘The quasi-solid-liquid phase transition exists widely in different fields,and attracts more attention due to its instinctive mechanism.The structure of force chains is an important factor to describe the phase transition properties.In this study,the discrete element model(DEM) is adopted to simulate a simple granular shear flow with period boundary condition on micro scale.The quasi-solid-liquid phase transition is obtained under various volume fractions and shear rates.Based on the DEM results,the probability distribution functions of the inter-particle contact force are obtained in different shear flow phases.The normal,tangential and total contact forces have the same distributions.The distribution can be fitted as the exponential function for the liquid-like phase,and as the Weibull function for the solid-like phase.To describe the progressive evolution of the force distribution in phase transition,we use the Weibull function and Corwin-Ngan function,respectively.Both of them can determine the probability distributions in different phases and the Weibull function shows more reasonable results.Finally,the force distributions are discussed to explain the characteristics of the force chain in the phase transition of granular shear flow.The distribution of the contact force is an indicator to determine the flow phase of granular materials.With the discussions on the statistical properties of the force chain,the phase transition of granular matter can be well understood.
