To reveal the affecting mechanism of cooling rate on lamellarαprecipitation,the precipitation behaviors of lamellarαphase in IMI834 titanium alloy during isothermal and non-isothermal heat treatments were quantitati...To reveal the affecting mechanism of cooling rate on lamellarαprecipitation,the precipitation behaviors of lamellarαphase in IMI834 titanium alloy during isothermal and non-isothermal heat treatments were quantitatively characterized using experimental analysis.Critical precipitation temperatures at various cooling rates were obtained using thermal dilatation testing.Using metallographic microscopy,electron microprobe analysis,and data fitting methods,the quantitative evolution models of average width,volume fraction,and solute concentration in theαandβphases were built for different temperatures or cooling rates.A comparison between the two precipitation behaviors showed that the average width and volume fraction of lamellarαphase under non-isothermal conditions were smaller than those under isothermal conditions.With increasing cooling rate,the average width and volume fraction were decreased significantly,and the critical precipitation temperatures were reduced.This phenomenon is mainly attributed to the decreased diffusion velocity of solutes Al,Mo,and Nb with increasing cooling rate.展开更多
Reanalysis data from NCEP/NCAR are used to systematically study preceding signals of monthly precipitation anomalies in the early raining season of Guangdong province, from the viewpoints of 500-hPa geopotential heigh...Reanalysis data from NCEP/NCAR are used to systematically study preceding signals of monthly precipitation anomalies in the early raining season of Guangdong province, from the viewpoints of 500-hPa geopotential height field, outgoing longwave radiation (OLR) field, sea surface temperature (SST) and fourteen indexes of general circulation depicting atmosphere activity at high, middle and low latitutes. Being multiple tools of information, a number of conceptual models are formulated that are useful for prediction of the magnitude of monthly precipitation (drought, flood and normal conditionss).展开更多
The ozone occurs naturally in the atmosphere and presents a filter of protection, absorbing the radiations wavelengths lower than 310 nm. The industrial generation of ozone is the classical application of the non-equi...The ozone occurs naturally in the atmosphere and presents a filter of protection, absorbing the radiations wavelengths lower than 310 nm. The industrial generation of ozone is the classical application of the non-equilibrium air plasmas at the atmospheric pressure. A low temperature is needed because the ozone quickly decays at the high temperature. This study is based on a temporal kinetic model for the production of ozone. The chemical kinetics take into account 96 reactions with 19 species atomic and molecular created in the discharge. In this work, the model allows to calculate the temporal evolution of neutral, ionized and excited species concentrations in plasma. The results show the influence of the kinetic on the ozone production yield and on the gas heating by Joule effect.展开更多
Experiments were performed on the crystallization of a CuSO4 solution upon the action of the temperature gradient with the forming of mono crystals three wedges crystal system （prisms）. We found that the fractal dim...Experiments were performed on the crystallization of a CuSO4 solution upon the action of the temperature gradient with the forming of mono crystals three wedges crystal system （prisms）. We found that the fractal dimension of crystals equals 2.45, which is consistent with the literature data. Crystal growth is represented as the N-rd translation of each side of the crystal lattice with its own speed and with relation to the formation of similar structures--fractals. A mathematical model of ultrasonic crystallization of a CuSO4 solution was proposed. The model is based on the combined use of differential transport equations of momentum, mass, energy and sound waves and a method of similarity and dimensional analysis. The calculated formulas for the concentration of Ccr, the equivalent diameter of the formed crystals dcr and the intensity of internal energy source Ф, associated with the interaction of crystals with the hydro mechanical, heat and sound fields were obtained. Fractal interpretation of ultrasonic crystallization of the CuSO4 solution was made. It was found that on the growth of crystal size d^r directly affects translation N, i.e., an increase in the number of sets of crystals of infinitely small size e, correspond to the size of the crystal lattice. In turn, translation of crystals depends on the geometry of the crystallizer and the physical parameters of external force fields, acting on the CuSO4 solution. A connection of results of the mathematical modeling with the results of fractal analysis of the ultrasonic crystallization of solutions was established.展开更多
Coronaviruses (CoVs) are generally associated with respiratory and enteric infections and have long been recognized as important pathogens of livestock and companion animals. Mouse hepatitis virus (MHV) is a widely st...Coronaviruses (CoVs) are generally associated with respiratory and enteric infections and have long been recognized as important pathogens of livestock and companion animals. Mouse hepatitis virus (MHV) is a widely studied model system for Coronavirus replication and pathogenesis. In this study,we created a MHV-A59 temperature sensitive (ts) mutant Wu"-ts18(cd) using the recombinant vaccinia reverse genetics system. Virus replication assay in 17C1-1 cells showed the plaque phenotype and replication characterization of constructed Wu"-ts18(cd) were indistinguishable from the reported ts mutant Wu"-ts18. Then we cultured the ts mutant Wu"-ts18(cd) at non-permissive temperature 39.5°C,which "forced" the ts recombinant virus to use second-site mutation to revert from a ts to a non-ts phenotype. Sequence analysis showed most of the revertants had the same single amino acid mutation at Nsp16 position 43. The single amino acid mutation at Nsp16 position 76 or position 130 could also revert the ts mutant Wu"-ts18 (cd) to non-ts phenotype,an additional independent mutation in Nsp13 position 115 played an important role on plaque size. The results provided us with genetic information on the functional determinants of Nsp16. This allowed us to build up a more reasonable model of CoVs replication-transcription complex.展开更多
Standard treatments of thermodynamic equilibrium are incomplete. They do not take account of all factors determining equilibrium, cannot explain why many systems do not reach equilibrium and do not discuss the questio...Standard treatments of thermodynamic equilibrium are incomplete. They do not take account of all factors determining equilibrium, cannot explain why many systems do not reach equilibrium and do not discuss the questions of reaching and maintaining equilibrium. The arguments presented here provide a single physical definition of thermodynamic equilibrium that accounts for all factors determining thermodynamic equilibrium for mixtures of combustible gases and air. Based on the standard delrmition of thermodynamic equilibrium, the MBD （Maxwell Boltzmann distribution） and a simple molecular model lead to three possible types of equilibrium. The regions of temperature pressure and composition for each type of equilibrium are defined by the measured values of ignition temperatures and the explosive and flammability limits. How this definition of thermodynamic equilibrium can be extended to all molecular systems is discussed in the following papers.展开更多
Temperature as an indicator of tissue response is widely used in clinical applications. In view of above a problem of temperature distribution in peripheral regions of extended spherical organs of a human body like, h...Temperature as an indicator of tissue response is widely used in clinical applications. In view of above a problem of temperature distribution in peripheral regions of extended spherical organs of a human body like, human breast involving uniformly perfused tumor is investigated in this paper. The human breast is assumed to be spherical in shape with upper hemisphere projecting out from the trunk of the body and lower hemisphere is considered to be a part of the body core. The outer surface of the breast is assumed to be exposed to the environment from where the heat loss takes place by conduction, convection, radiation and evaporation. The heat transfer from core to the surface takes place by thermal conduction and blood perfusion. Also metabolic activity takes place at different rates in different layers of the breast. An elliptical-shaped tumor is assumed to be present in the dermis region of human breast. A finite element model is developed for a two-dimensional steady state case incorporating the important parameters like blood flow, metabolic activity and thermal conductivity. The triangular ring elements are employed to discretize the region. Appropriate boundary conditions are framed using biophysical conditions. The numerical results are used to study the effect of tumor on temperature distribution in the region.展开更多
基金financial supports from the National Natural Science Foundation of China(No.51675433)the Natural Science Foundation for Distinguished Young Scholars of Shaanxi Province,China(No.2019JC-09)。
文摘To reveal the affecting mechanism of cooling rate on lamellarαprecipitation,the precipitation behaviors of lamellarαphase in IMI834 titanium alloy during isothermal and non-isothermal heat treatments were quantitatively characterized using experimental analysis.Critical precipitation temperatures at various cooling rates were obtained using thermal dilatation testing.Using metallographic microscopy,electron microprobe analysis,and data fitting methods,the quantitative evolution models of average width,volume fraction,and solute concentration in theαandβphases were built for different temperatures or cooling rates.A comparison between the two precipitation behaviors showed that the average width and volume fraction of lamellarαphase under non-isothermal conditions were smaller than those under isothermal conditions.With increasing cooling rate,the average width and volume fraction were decreased significantly,and the critical precipitation temperatures were reduced.This phenomenon is mainly attributed to the decreased diffusion velocity of solutes Al,Mo,and Nb with increasing cooling rate.
基金Short-term Climate Prediction Study for Guangdong Province a key project of Guangdong Science and Technology Committee in the national 9th five-year economic development plan Research on Long-term Tendency Prediction System for Floods/Drought and Typh
文摘Reanalysis data from NCEP/NCAR are used to systematically study preceding signals of monthly precipitation anomalies in the early raining season of Guangdong province, from the viewpoints of 500-hPa geopotential height field, outgoing longwave radiation (OLR) field, sea surface temperature (SST) and fourteen indexes of general circulation depicting atmosphere activity at high, middle and low latitutes. Being multiple tools of information, a number of conceptual models are formulated that are useful for prediction of the magnitude of monthly precipitation (drought, flood and normal conditionss).
文摘The ozone occurs naturally in the atmosphere and presents a filter of protection, absorbing the radiations wavelengths lower than 310 nm. The industrial generation of ozone is the classical application of the non-equilibrium air plasmas at the atmospheric pressure. A low temperature is needed because the ozone quickly decays at the high temperature. This study is based on a temporal kinetic model for the production of ozone. The chemical kinetics take into account 96 reactions with 19 species atomic and molecular created in the discharge. In this work, the model allows to calculate the temporal evolution of neutral, ionized and excited species concentrations in plasma. The results show the influence of the kinetic on the ozone production yield and on the gas heating by Joule effect.
文摘Experiments were performed on the crystallization of a CuSO4 solution upon the action of the temperature gradient with the forming of mono crystals three wedges crystal system （prisms）. We found that the fractal dimension of crystals equals 2.45, which is consistent with the literature data. Crystal growth is represented as the N-rd translation of each side of the crystal lattice with its own speed and with relation to the formation of similar structures--fractals. A mathematical model of ultrasonic crystallization of a CuSO4 solution was proposed. The model is based on the combined use of differential transport equations of momentum, mass, energy and sound waves and a method of similarity and dimensional analysis. The calculated formulas for the concentration of Ccr, the equivalent diameter of the formed crystals dcr and the intensity of internal energy source Ф, associated with the interaction of crystals with the hydro mechanical, heat and sound fields were obtained. Fractal interpretation of ultrasonic crystallization of the CuSO4 solution was made. It was found that on the growth of crystal size d^r directly affects translation N, i.e., an increase in the number of sets of crystals of infinitely small size e, correspond to the size of the crystal lattice. In turn, translation of crystals depends on the geometry of the crystallizer and the physical parameters of external force fields, acting on the CuSO4 solution. A connection of results of the mathematical modeling with the results of fractal analysis of the ultrasonic crystallization of solutions was established.
基金Research Grants from State Key Laboratory of Pathogen and Biosecurity (SKLPBS0918)
文摘Coronaviruses (CoVs) are generally associated with respiratory and enteric infections and have long been recognized as important pathogens of livestock and companion animals. Mouse hepatitis virus (MHV) is a widely studied model system for Coronavirus replication and pathogenesis. In this study,we created a MHV-A59 temperature sensitive (ts) mutant Wu"-ts18(cd) using the recombinant vaccinia reverse genetics system. Virus replication assay in 17C1-1 cells showed the plaque phenotype and replication characterization of constructed Wu"-ts18(cd) were indistinguishable from the reported ts mutant Wu"-ts18. Then we cultured the ts mutant Wu"-ts18(cd) at non-permissive temperature 39.5°C,which "forced" the ts recombinant virus to use second-site mutation to revert from a ts to a non-ts phenotype. Sequence analysis showed most of the revertants had the same single amino acid mutation at Nsp16 position 43. The single amino acid mutation at Nsp16 position 76 or position 130 could also revert the ts mutant Wu"-ts18 (cd) to non-ts phenotype,an additional independent mutation in Nsp13 position 115 played an important role on plaque size. The results provided us with genetic information on the functional determinants of Nsp16. This allowed us to build up a more reasonable model of CoVs replication-transcription complex.
文摘Standard treatments of thermodynamic equilibrium are incomplete. They do not take account of all factors determining equilibrium, cannot explain why many systems do not reach equilibrium and do not discuss the questions of reaching and maintaining equilibrium. The arguments presented here provide a single physical definition of thermodynamic equilibrium that accounts for all factors determining thermodynamic equilibrium for mixtures of combustible gases and air. Based on the standard delrmition of thermodynamic equilibrium, the MBD （Maxwell Boltzmann distribution） and a simple molecular model lead to three possible types of equilibrium. The regions of temperature pressure and composition for each type of equilibrium are defined by the measured values of ignition temperatures and the explosive and flammability limits. How this definition of thermodynamic equilibrium can be extended to all molecular systems is discussed in the following papers.
文摘Temperature as an indicator of tissue response is widely used in clinical applications. In view of above a problem of temperature distribution in peripheral regions of extended spherical organs of a human body like, human breast involving uniformly perfused tumor is investigated in this paper. The human breast is assumed to be spherical in shape with upper hemisphere projecting out from the trunk of the body and lower hemisphere is considered to be a part of the body core. The outer surface of the breast is assumed to be exposed to the environment from where the heat loss takes place by conduction, convection, radiation and evaporation. The heat transfer from core to the surface takes place by thermal conduction and blood perfusion. Also metabolic activity takes place at different rates in different layers of the breast. An elliptical-shaped tumor is assumed to be present in the dermis region of human breast. A finite element model is developed for a two-dimensional steady state case incorporating the important parameters like blood flow, metabolic activity and thermal conductivity. The triangular ring elements are employed to discretize the region. Appropriate boundary conditions are framed using biophysical conditions. The numerical results are used to study the effect of tumor on temperature distribution in the region.
