A total of 80 weathering pits （gnammas）, located on granite surfaces of Qing Mountain （青山）, Hexigten （克什克腾） Global Geopark, Inner Mongolia, were identified and measured in terms of dimensional and orientat...A total of 80 weathering pits （gnammas）, located on granite surfaces of Qing Mountain （青山）, Hexigten （克什克腾） Global Geopark, Inner Mongolia, were identified and measured in terms of dimensional and orientational features. This article attempts to extract characteristics of the weathering pits by descriptive statistics and orientation rose diagrams, investigate the multi-phase evolution by the modified gnamma morphological analysis （GMA） method, and shed new light on the possible genesis and the influencing factors. Following the modified GMA method, weathering pits in Qing Mountain have been divided into six groups and compared with analogous sites to deduce their approximate age, which might be no older than 30 ka B.P., and explore the possibility that the multi-phase evolution of weathering pits may arise from responses to climate change. In consequence, we suggest that the combination of weathering, especially salt weathering, and wind erosion, both of which are closely related to climatic variation, take the main responsibility for the formation and development of weathering pits in Qing Mountain.展开更多
Thermodynamic and chemical properties of liquid carbon dioxide and nitrogen（CO_（2~–）N_2） mixture under the conditions of extremely high densities and temperatures are studied by using quantum molecular dynamic（...Thermodynamic and chemical properties of liquid carbon dioxide and nitrogen（CO_（2~–）N_2） mixture under the conditions of extremely high densities and temperatures are studied by using quantum molecular dynamic（QMD） simulations based on density functional theory including dispersion corrections（DFT-D）. We present equilibrium properties of liquid mixture for 112 separate density and temperature points, by selecting densities ranging from ρ = 1.80 g/cm^3 to 3.40 g/cm^3 and temperatures from T = 500 K to 8000 K. In the range of our study, the liquid CO_（2~–）N_2 mixture undergoes a continuous transition from molecular to atomic fluid state and liquid polymerization inferred from pair correlation functions（PCFs）and the distribution of various molecular components. The insulator–metal transition is demonstrated by means of the electronic density of states（DOS）.展开更多
Objectives To assess the effect of delayed opening the infarct - related artery (IRA) by percutanous coronary intervention (PCI) on the late phase left ventricular function after acute ante- rior myocardial infarction...Objectives To assess the effect of delayed opening the infarct - related artery (IRA) by percutanous coronary intervention (PCI) on the late phase left ventricular function after acute ante- rior myocardial infarction. Methods 64 patients with initial Q - wave anterior myocardial infarction and the infarct - related arteries were total occluded conformed by angiogram at 2 to 14 days after onset were divided into successful PCI group and control group ( not re- ceiving PCI or the IRA not re - opened). 2 - DE was performed at early phase ( about 3 weeks) , 2 and 6 months after onset of AMI respectively to detect the left ventricular function and left ventricular wall motion ab- normality (VWMA). The total congestive heart failure events were recorded during 6 months follow-up. Re- sults VWMA scores, left ventricular ejection frac- tion (LVEF) , left ventricular end - diastolic and end - systolic volume indices ( LVEDVI and LVDSVI) were similar in 2 groups at early phase and 2 months. There were no differences between early phase and 2 months in each group too. VWMA scores and LVEF did not changed at 6 months in each group compared with the early phase and 2 months ( P > 0. 05 ). But LVEDVI and LVESVI were significantly smaller in the successful PCI group than in the control group (P < 0.01, P < 0. 05). The congestive heart failure events were taken place in 19% of patients in control group com- pared with 2% in successful PCI group ( P > 0. 05 ). Conclusions Although the infarct size does not changed, delayed opening the IRA has beneficial effect to the late phase left ventricular dilatation after acuteanterior myocardial infarction.展开更多
Over the past decades evidence has been accumulating that intestinal barrier integrity loss plays a key role in the development and perpetuation of a variety of disease states including inflammatory bowel disease and ...Over the past decades evidence has been accumulating that intestinal barrier integrity loss plays a key role in the development and perpetuation of a variety of disease states including inflammatory bowel disease and celiac disease,and is a key player in the onset of sepsis and multiple organ failure in situations of intestinal hypoperfusion,including trauma and major surgery.Insight into gut barrier integrity and function loss is important to improve our knowledge on disease etiology and pathophysiology and contributes to early detection and/or secondary prevention of disease.A variety of tests have been developed to assess intestinal epithelial cell damage,intestinal tight junction status and consequences of intestinal barrier integrity loss,i.e.increased intestinal permeability.This review discusses currently available methods for evaluating loss of human intestinal barrier integrity and function.展开更多
The precursor of ammonium aluminum carbonate hydroxide was synthesized by using aluminum sulfate（Al2（SO4）3） and ammonium carbonate（（NH4）2CO3）. The effects of α-Al2O3 seeds and mixture composed of α-Al2O3 and...The precursor of ammonium aluminum carbonate hydroxide was synthesized by using aluminum sulfate（Al2（SO4）3） and ammonium carbonate（（NH4）2CO3）. The effects of α-Al2O3 seeds and mixture composed of α-Al2O3 and ammonium nitrate, as well as multiplex catalysts （AT） on phase transformation of alumina in sintering process were investigated respectively. The results show that the α-Al2O3 seeds and the mixture of α-Al2O3 and ammonium nitrate can lower the phase transformation temperature of α-Al2O3 to different extents while the particles obtained agglomerate heavily. AT has great potential synergistic effects on the phase transformation of alumina and reduces the phase transformation temperature of α-Al2O3 and the trends of necking-formation between particles. Therefore the dispersion of powder particles is improved significantly.展开更多
Theinitialstageofagingtransformationin Al 2 27% Li 2 68 % Cu 0 11% Zr 0 13% Ceal loy at100℃wasstudied by meansof x ray diffraction.It wasconcludedthatordering of Liatom happens whenthealloyissolution treated andquenc...Theinitialstageofagingtransformationin Al 2 27% Li 2 68 % Cu 0 11% Zr 0 13% Ceal loy at100℃wasstudied by meansof x ray diffraction.It wasconcludedthatordering of Liatom happens whenthealloyissolution treated andquenched, and beforetheformationofδ’ phasethereexitscontinuous phasetransformation processes, namely ordering ,spinodal de composition and both coexistence. Gunier Preston zone was not found in the aging process ofthestudied alloy.展开更多
This paper presents a new methodology for coarse-grained atomistic simulation of inelastic material behavior including phase transformations in ceramics and dislocation mediated plasticity in metals. The methodology c...This paper presents a new methodology for coarse-grained atomistic simulation of inelastic material behavior including phase transformations in ceramics and dislocation mediated plasticity in metals. The methodology combines an atomistic formulation of balance equations and a modified finite element method. With significantly fewer degrees of freedom than those of a fully atomistic model and without additional constitutive rules but the interatomic force field, the new coarse-grained （CG） method is shown to be feasible in predicting the nonlinear constitutive re- sponses of materials and also reproducing atomic-scale phenomena such as phase transformations （diamond --, 13-Sn） in silicon and dislocation nucleation and migration, formation of dislocation loops and stacking faults ribbons in single crystal nickel. Direct comparisons between CG and the corresponding full molecular dynamics （MD） simulations show that the present methodology is efficient and promising in modeling and simulation of inelastic material behavior without losing the essential atomistic features. The potential applications and the limitations of the CG method are also discussed.展开更多
The incubation period of proeutectoid ferrite transformation for Si-Mn transformation induced plasticity (TRIP) steel has been calculated by the Aaronson's incubation period model for transformation.The influences...The incubation period of proeutectoid ferrite transformation for Si-Mn transformation induced plasticity (TRIP) steel has been calculated by the Aaronson's incubation period model for transformation.The influences of chemical compositions and hot deformation of austenite on the incubation period have been taken into consideration in the calculation,and some parameters have been proposed and validated with the measured time temperature transformation (TTT) curves from dilation tests.The calculation results show that it is essential to take into account of the effect of solute atoms on the interfacial energy in the austenite grain boundaries.For hypoeutectoid steel,the incubation period of ferrite transformation increases with the increase of C and Mn contents,and C has a greater impact than that of Mn,while the incubation period of ferrite transformation decreases with the increase of Si content.Hot deformation shortens the incubation time and promotes austenite to ferrite transformation.展开更多
This paper is a continuation of one published in this journal nine months ago. The two papers present a model of cavitational luminescence (CL), multi-bubble sonoluminescence (MBSL), one-bubble sonoluminescence (OBSL)...This paper is a continuation of one published in this journal nine months ago. The two papers present a model of cavitational luminescence (CL), multi-bubble sonoluminescence (MBSL), one-bubble sonoluminescence (OBSL), and laser-induced bubble luminescence (LIBL). The basis of this model is the PeTa (Perel’man-Tatartchenko) effect, a nonequilibrium characteristic radiation under first-order phase transitions, especially vapour condensation. In this model, the main role is given to the liquid, where the evaporation, condensation, flash, and subsequent collapse of bubbles occur. The instantaneous vapour condensation inside the bubble is a reason for the CL/MBSL/OBSL/LIBL. Apparently, the dissolved gases and other impurities in the liquid are responsible for peaks that appear at the background of the main spectrum. They are most likely excited by a shock wave occurred during the collapse. This paper, in contrast to the previous one, presents a slightly expanded model that explains additional experimental data concerning especially the LIBL spectrum. As a result, today we are not aware of any experimental data that would contradict the PeTa model, and we continue to assert that there is no mystery to the CL/MBSL/OBSL/LIBL phenomena, as well as no reason to hope that they can be used for high-temperature chemical reactions, and even more so for a thermonuclear ones.展开更多
提出了一种基于射频调制-解调的光纤环干涉仪传感技术,用于双参量高精度无串扰传感。在低调制频率下光纤环干涉仪(Fiber Optic Ring Interferometer,FORI)对温度变化不敏感,而对损耗变化表现出灵活的可调谐灵敏度,其线性透射率灵敏度为0...提出了一种基于射频调制-解调的光纤环干涉仪传感技术,用于双参量高精度无串扰传感。在低调制频率下光纤环干涉仪(Fiber Optic Ring Interferometer,FORI)对温度变化不敏感,而对损耗变化表现出灵活的可调谐灵敏度,其线性透射率灵敏度为0.282 rad。通过选择特定的调制频率,可实现损耗的线性传感或最大灵敏度传感。在高调制频率下,利用温度引起的频移累积效应,通过追踪零相移点频率实现温度解调,灵敏度达-17.47 kHz/℃。实验结果表明,所提方法成功实现了透射率和温度的双参量无串扰同时测量。这种基于射频调制-解调的FORI传感技术展现了在多参量传感领域的应用潜力,为高精度、多功能光纤传感系统的发展提供了新的思路。展开更多
基金supported by China Geological Survey(No.11212011120118)the Fundamental Research Projects of China University of Geosciences,Beijing,China(No.2011YYL016)
文摘A total of 80 weathering pits （gnammas）, located on granite surfaces of Qing Mountain （青山）, Hexigten （克什克腾） Global Geopark, Inner Mongolia, were identified and measured in terms of dimensional and orientational features. This article attempts to extract characteristics of the weathering pits by descriptive statistics and orientation rose diagrams, investigate the multi-phase evolution by the modified gnamma morphological analysis （GMA） method, and shed new light on the possible genesis and the influencing factors. Following the modified GMA method, weathering pits in Qing Mountain have been divided into six groups and compared with analogous sites to deduce their approximate age, which might be no older than 30 ka B.P., and explore the possibility that the multi-phase evolution of weathering pits may arise from responses to climate change. In consequence, we suggest that the combination of weathering, especially salt weathering, and wind erosion, both of which are closely related to climatic variation, take the main responsibility for the formation and development of weathering pits in Qing Mountain.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11374217,11135012,and 11375262)the Joint Fund of the National Natural Science Foundation of Chinathe China Academy of Engineering Physics(Grant No.11176020)
文摘Thermodynamic and chemical properties of liquid carbon dioxide and nitrogen（CO_（2~–）N_2） mixture under the conditions of extremely high densities and temperatures are studied by using quantum molecular dynamic（QMD） simulations based on density functional theory including dispersion corrections（DFT-D）. We present equilibrium properties of liquid mixture for 112 separate density and temperature points, by selecting densities ranging from ρ = 1.80 g/cm^3 to 3.40 g/cm^3 and temperatures from T = 500 K to 8000 K. In the range of our study, the liquid CO_（2~–）N_2 mixture undergoes a continuous transition from molecular to atomic fluid state and liquid polymerization inferred from pair correlation functions（PCFs）and the distribution of various molecular components. The insulator–metal transition is demonstrated by means of the electronic density of states（DOS）.
文摘Objectives To assess the effect of delayed opening the infarct - related artery (IRA) by percutanous coronary intervention (PCI) on the late phase left ventricular function after acute ante- rior myocardial infarction. Methods 64 patients with initial Q - wave anterior myocardial infarction and the infarct - related arteries were total occluded conformed by angiogram at 2 to 14 days after onset were divided into successful PCI group and control group ( not re- ceiving PCI or the IRA not re - opened). 2 - DE was performed at early phase ( about 3 weeks) , 2 and 6 months after onset of AMI respectively to detect the left ventricular function and left ventricular wall motion ab- normality (VWMA). The total congestive heart failure events were recorded during 6 months follow-up. Re- sults VWMA scores, left ventricular ejection frac- tion (LVEF) , left ventricular end - diastolic and end - systolic volume indices ( LVEDVI and LVDSVI) were similar in 2 groups at early phase and 2 months. There were no differences between early phase and 2 months in each group too. VWMA scores and LVEF did not changed at 6 months in each group compared with the early phase and 2 months ( P > 0. 05 ). But LVEDVI and LVESVI were significantly smaller in the successful PCI group than in the control group (P < 0.01, P < 0. 05). The congestive heart failure events were taken place in 19% of patients in control group com- pared with 2% in successful PCI group ( P > 0. 05 ). Conclusions Although the infarct size does not changed, delayed opening the IRA has beneficial effect to the late phase left ventricular dilatation after acuteanterior myocardial infarction.
基金Supported by the Construction Fund for National Feature Specialty(TS11496)he Anhui Natural Science Fund for Institutions of Higher Education(KJ2010B431)he Natural Science Fund of Inner Mongolia University for the Nationalities(NMD1227)
文摘Over the past decades evidence has been accumulating that intestinal barrier integrity loss plays a key role in the development and perpetuation of a variety of disease states including inflammatory bowel disease and celiac disease,and is a key player in the onset of sepsis and multiple organ failure in situations of intestinal hypoperfusion,including trauma and major surgery.Insight into gut barrier integrity and function loss is important to improve our knowledge on disease etiology and pathophysiology and contributes to early detection and/or secondary prevention of disease.A variety of tests have been developed to assess intestinal epithelial cell damage,intestinal tight junction status and consequences of intestinal barrier integrity loss,i.e.increased intestinal permeability.This review discusses currently available methods for evaluating loss of human intestinal barrier integrity and function.
文摘The precursor of ammonium aluminum carbonate hydroxide was synthesized by using aluminum sulfate（Al2（SO4）3） and ammonium carbonate（（NH4）2CO3）. The effects of α-Al2O3 seeds and mixture composed of α-Al2O3 and ammonium nitrate, as well as multiplex catalysts （AT） on phase transformation of alumina in sintering process were investigated respectively. The results show that the α-Al2O3 seeds and the mixture of α-Al2O3 and ammonium nitrate can lower the phase transformation temperature of α-Al2O3 to different extents while the particles obtained agglomerate heavily. AT has great potential synergistic effects on the phase transformation of alumina and reduces the phase transformation temperature of α-Al2O3 and the trends of necking-formation between particles. Therefore the dispersion of powder particles is improved significantly.
文摘Theinitialstageofagingtransformationin Al 2 27% Li 2 68 % Cu 0 11% Zr 0 13% Ceal loy at100℃wasstudied by meansof x ray diffraction.It wasconcludedthatordering of Liatom happens whenthealloyissolution treated andquenched, and beforetheformationofδ’ phasethereexitscontinuous phasetransformation processes, namely ordering ,spinodal de composition and both coexistence. Gunier Preston zone was not found in the aging process ofthestudied alloy.
基金supported by the National Science Foundation under award numbers CMMI-0855795 and 1129976DARPA under award number N66001-10-1-4018+1 种基金Department of Energy under award number DOE/DE-SC0006539supported in part by the National Science Foundation through Teragrid resources provided by TACC
文摘This paper presents a new methodology for coarse-grained atomistic simulation of inelastic material behavior including phase transformations in ceramics and dislocation mediated plasticity in metals. The methodology combines an atomistic formulation of balance equations and a modified finite element method. With significantly fewer degrees of freedom than those of a fully atomistic model and without additional constitutive rules but the interatomic force field, the new coarse-grained （CG） method is shown to be feasible in predicting the nonlinear constitutive re- sponses of materials and also reproducing atomic-scale phenomena such as phase transformations （diamond --, 13-Sn） in silicon and dislocation nucleation and migration, formation of dislocation loops and stacking faults ribbons in single crystal nickel. Direct comparisons between CG and the corresponding full molecular dynamics （MD） simulations show that the present methodology is efficient and promising in modeling and simulation of inelastic material behavior without losing the essential atomistic features. The potential applications and the limitations of the CG method are also discussed.
基金the Scientific and Technical Supporting Program of China during the 11th Five-Year Plan(No.2006BAE03A08)
文摘The incubation period of proeutectoid ferrite transformation for Si-Mn transformation induced plasticity (TRIP) steel has been calculated by the Aaronson's incubation period model for transformation.The influences of chemical compositions and hot deformation of austenite on the incubation period have been taken into consideration in the calculation,and some parameters have been proposed and validated with the measured time temperature transformation (TTT) curves from dilation tests.The calculation results show that it is essential to take into account of the effect of solute atoms on the interfacial energy in the austenite grain boundaries.For hypoeutectoid steel,the incubation period of ferrite transformation increases with the increase of C and Mn contents,and C has a greater impact than that of Mn,while the incubation period of ferrite transformation decreases with the increase of Si content.Hot deformation shortens the incubation time and promotes austenite to ferrite transformation.
文摘This paper is a continuation of one published in this journal nine months ago. The two papers present a model of cavitational luminescence (CL), multi-bubble sonoluminescence (MBSL), one-bubble sonoluminescence (OBSL), and laser-induced bubble luminescence (LIBL). The basis of this model is the PeTa (Perel’man-Tatartchenko) effect, a nonequilibrium characteristic radiation under first-order phase transitions, especially vapour condensation. In this model, the main role is given to the liquid, where the evaporation, condensation, flash, and subsequent collapse of bubbles occur. The instantaneous vapour condensation inside the bubble is a reason for the CL/MBSL/OBSL/LIBL. Apparently, the dissolved gases and other impurities in the liquid are responsible for peaks that appear at the background of the main spectrum. They are most likely excited by a shock wave occurred during the collapse. This paper, in contrast to the previous one, presents a slightly expanded model that explains additional experimental data concerning especially the LIBL spectrum. As a result, today we are not aware of any experimental data that would contradict the PeTa model, and we continue to assert that there is no mystery to the CL/MBSL/OBSL/LIBL phenomena, as well as no reason to hope that they can be used for high-temperature chemical reactions, and even more so for a thermonuclear ones.
