The effects of impurities on ion temperature gradient(ITG)driven turbulence transport in tokamak core plasmas are investigated numerically via global simulations of microturbulence with carbon impurities and adiabatic...The effects of impurities on ion temperature gradient(ITG)driven turbulence transport in tokamak core plasmas are investigated numerically via global simulations of microturbulence with carbon impurities and adiabatic electrons.The simulations use an extended fluid code(ExFC)based on a four-field gyro-Landau-fluid(GLF)model.The multispecies form of the normalized GLF equations is presented,which guarantees the self-consistent evolution of both bulk ions and impurities.With parametric profiles of the cyclone base case,well-benchmarked ExFC is employed to perform simulations focusing on different impurity density profiles.For a fixed temperature profile,it is found that the turbulent heat diffusivity of bulk ions in a quasi-steady state is usually lower than that without impurities,which is contrary to the linear and quasilinear predictions.The evolutions of the temperature gradient and heat diffusivity exhibit a fast relaxation process,indicating that the destabilization of the outwardly peaked impurity profile is a transient state response.Furthermore,the impurity effects from different profiles can obviously influence the nonlinear critical temperature gradient,which is likely to be dominated by linear effects.These results suggest that the improvement in plasma confinement could be attributed to the impurities,most likely through adjusting both heat diffusivity and the critical temperature gradient.展开更多
Hydride precipitation in zirconium cladding materials can damage their integrity and durability.Service temperature and material defects have a significant effect on the dynamic growth of hydrides.In this study,we hav...Hydride precipitation in zirconium cladding materials can damage their integrity and durability.Service temperature and material defects have a significant effect on the dynamic growth of hydrides.In this study,we have developed a phasefield model based on the assumption of elastic behaviour within a specific temperature range(613 K-653 K).This model allows us to study the influence of temperature and interfacial effects on the morphology,stress,and average growth rate of zirconium hydride.The results suggest that changes in temperature and interfacial energy influence the length-to-thickness ratio and average growth rate of the hydride morphology.The ultimate determinant of hydride orientation is the loss of interfacial coherency,primarily induced by interfacial dislocation defects and quantifiable by the mismatch degree q.An escalation in interfacial coherency loss leads to a transition of hydride growth from horizontal to vertical,accompanied by the onset of redirection behaviour.Interestingly,redirection occurs at a critical mismatch level,denoted as qc,and remains unaffected by variations in temperature and interfacial energy.However,this redirection leads to an increase in the maximum stress,which may influence the direction of hydride crack propagation.This research highlights the importance of interfacial coherency and provides valuable insights into the morphology and growth kinetics of hydrides in zirconium alloys.展开更多
The armyworm Mythimna roseilinea(Walker) is a major pest of grain crops in South China. So far little is known about its basic biology and ecology, making prediction of population dynamics difficult. This study exam...The armyworm Mythimna roseilinea(Walker) is a major pest of grain crops in South China. So far little is known about its basic biology and ecology, making prediction of population dynamics difficult. This study examined the relationships of individual development and population growth with temperature based on an age-stage, two-sex life table of M. roseilinea reared on maize in the laboratory at 18, 21, 24, 27 and 30℃. The highest values of net reproductive rate(R_0) and fecundity were observed at 21 and 24℃, respectively. Both the intrinsic rate of increase(r) and finite rate of increase(λ) increased significantly and mean generation time(T) decreased significantly with increasing temperature. M. roseilinea was able to develop, survive and lay eggs at all temperature regimes tested. Development rates of the egg, larval, pupal, as well as the whole pre-oviposition stages had a positive linear relationship with temperature. The calculated development threshold temperatures of egg, larval, pupal, pre-oviposition and total pre-oviposition stages were 13.29, 8.39, 14.35, 7.42, and 12.24℃, respectively, and their effective accumulated temperatures were 63.59, 445.00, 211.11, 89.02, and 698.95 degree-days, respectively. These results provide insight into temperature-based phenology and population ecology of this insect pest and will allow population prediction and management available in the field.展开更多
At present, the most researches on the protected effect of shelterbelt are on the basis of the two scales of forest belts and networks. However, with the further research on the global environmental change, more atten...At present, the most researches on the protected effect of shelterbelt are on the basis of the two scales of forest belts and networks. However, with the further research on the global environmental change, more attention was paid to the regional climate effect of shelterbelt. In present study, we analyzed the temperature effect of the shelterbelt at regional scale by using the land surface temperature (LST) data from the moderate resolution imaging spectroradiometer (MODIS) at Yushu, Nong'an, Dehui, and Fuyu in Jilin Province of China from March to October in 2008. Results show that the shelterbelt can increase the soil temperature of the protected farmland as compared with no shelterbelt zone, with the increment of 0.57oC per day in fine shelterbelt and 0.38oC per day in the normal shelterbelt. Moreover, the correlation analysis of the air temperature, precipitation and the soil type and the shelterbelt effect shows that the air temperature and precipitation are negatively correlated with the shelterbelt effects, that is, the more the temperature and precipitation are, the less the effect produced. While the impact of the soil types on the shelterbelt's effect is not very obvious as a whole. This paper draws significance in terms of analyzing the effects of the shelterbelt on the soil temperature at regional scale utilizing the remotely sensed data and GIS technique.展开更多
Seasonal variation of stable isotopes in precipitation of Kathmandu Valley on the southem slope of Himalaya was carried out to understand the controlling mechanism of amount and temperature effect on the basis of one ...Seasonal variation of stable isotopes in precipitation of Kathmandu Valley on the southem slope of Himalaya was carried out to understand the controlling mechanism of amount and temperature effect on the basis of one year stable isotope data from 2010 to 2011. Highly depleted isotope values in major rainy period are obtained just after the onset of precipitation in summer, which ac- counts for "amount effect" due to saturation isotopic compositions in high moisture condition, whereas, the higher values in winter are indicative to regional vapors (temperature effect) recycling of various sources. An abrupt depletion of isotope values in mid- June, indicates the onset date of monsoon precipitation, by the replacement of winter air mass with southem monsoon. Thus, pre- cipitation isotopes are a tool revealing the onset date of summer monsoon and temporal features of variability, in local and regional monsoons precipitations. A comparison of long term monthly values of 5180, temperature, and precipitation with GNIP 6180 data shows the temporal variations of stable isotopes are mostly controlled by amount and temperature effects. During summer mon- soon, the amount effects are stronger for high values of precipitation (R=0.7) and altitude effect appears for low moisture in late rainy season, thus from December to June (winter to pre-monsoon) the controlling features of isotopes remains under the temper- ature effect. A temporal rate of temperature effect is derived as 0.04%0 per year which indicates a dry signal of atmospheric condition and a temperature relation 5180=(0.371±0.08)T+(0.156±0.05) is obtained from this analysis. The meteoric water lines of Kathmandu before and after monsoon onset of 2011, are found as 5D=(4.36±0.3)5180+(15.66±1.2) and 5D=(6.91±0.2)S180-(7.92±2.26) from lab samples result, and 5D=9.25180+11.725 and 5D=8.535180+16.65 from GNIP data, which lacks the consistency both for slopes and intercepts values for the study period. The mean lapse rate values of δ18O and δD from GNIP data are obtained as -0.002‰/m and -0.015 ‰/m, which indicate the altitudinal effects in regional precipitation of the southern slope of Himalayas. This study estimates new stable isotopes data in recent precipitation using simple methodology which can be important for regional precipitation monitoring systems, environmental change and paleo-climatic studies.展开更多
Rock is generally complex and heterogeneous,therefore the heterogeneity effects of effective stress and temperature on permeability should be taken into account.In this study,two-part Hooke’s model(TPHM) is introdu...Rock is generally complex and heterogeneous,therefore the heterogeneity effects of effective stress and temperature on permeability should be taken into account.In this study,two-part Hooke’s model(TPHM) is introduced to understand the influences of effective stress and temperature on permeability of soft and hard parts(two parts) of rock based on coupling thermo-hydro-mechanical tests.Under a fixed temperature level(25 ℃.35 ℃.50 ℃.65 ℃.80 ℃.90 ℃ and 95 ℃).the tests were carried out in a conventional triaxial system whereas the confining pressure was remained at 50 MPa.and the pore pressure was increased to the specified levels step by step.i.e.8 MPa,18 MPa.28 MPa.38 MPa.41 MPa,44 MPa.46 MPa and 48 MPa.The temperature-dependent relationships for two parts permeabilities are proposed on the basis of the initial test results.We point out that temperature of 65 ℃-90 ℃ is the threshold for the development of CO2-plume geothermal(CPC) reservoir sandstone cracking under low effective stress(2-9 MPa) based on the relationship between temperature and soft part permeability.Furthermore,we discuss the effect of temperature on the two parts in the rock.The results indicate that as the temperature increases from 25 ℃ to 65 ℃.the flow channel in the hard part has a stronger response to temperature than that in the soft part at a fixed effective stress level,which is opposite to the situation of effective stress.Considering that natural rock is generally heterogeneous with non-uniform pore structure,we suggest a physical interpretation of the phenomenon that before the thermal cracking threshold the two parts have different responses to temperature.展开更多
Temperature front (TF) is one of the important features in the Yellow Sea, which forms in spring,thrives in summer, and fades in autumn as thermocline declines. TF intensity |ST| is defined to describe the distributio...Temperature front (TF) is one of the important features in the Yellow Sea, which forms in spring,thrives in summer, and fades in autumn as thermocline declines. TF intensity |ST| is defined to describe the distribution of TF. Based on the MASNUM wave-tide-circulation coupled model, temperature distribution in the Yellow Sea was simulated with and without tidal effects. Along 36°N, distribution of TF from the simulated results are compared with the observations, and a quantitative analysis is introduced to evaluate the tidal effects on the forming and maintaining processes of the TF. Tidal mixing and the circulation structure adapting to it are the main causes of the TF.展开更多
Effects of temperature and drying and wetting alternation(DWA)on ammonium fixation in manured loessial soil were studied by means of Batch Equilibrium with Varying concentration solutions of ammonium chloride,ammonium...Effects of temperature and drying and wetting alternation(DWA)on ammonium fixation in manured loessial soil were studied by means of Batch Equilibrium with Varying concentration solutions of ammonium chloride,ammonium fixation time,and soil clay contents.The purpose of the research was to find out the pattern of ammonium fixation ted by the varying factors.The results showed a remarkable variation in ammonium fixation.Fixed ammonium increased with temperature and treatments of DWA.The ammonium fixation in manured loessial soil was characterized by the effect of temperature and DWA.展开更多
On the condition of electric-LO phonon strong coupling in a parabolic quantum dot,we obtain theeigenenergy and the eigenfunctions of the ground state and the first-excited state using the variational method ofPekar ty...On the condition of electric-LO phonon strong coupling in a parabolic quantum dot,we obtain theeigenenergy and the eigenfunctions of the ground state and the first-excited state using the variational method ofPekar type.This system in a quantum dot may be employed as a two-level quantum system-qubit.When the electronis in the superposition state of the ground state and the first-excited state,we obtain the time evolution of the electrondensity.The relations of the probability density of electron on the temperature and the electron-LO-phonon couplingconstant and the relations of the period of oscillation on the temperature,the electron-LO-phonon coupling constant,the Coulomb binding parameter and the confinement length are derived.The results show that the probability densityof electron oscillates with a period when the electron is in the superposition state of the ground and the first-excitedstate,and show that there are different laws that the probability density of electron and the period of oscillation changewith the temperature and the electron-LO-phonon coupling constant when the temperature is lower or higher.Andit is obtained that the period of oscillation decreases with increasing the Coulomb bound potential and increases withincreasing the confinement length not only at lower temperatures but also at higher temperatures.展开更多
On the basis of digital records from Tayuan well, we study coseismic effects of water temperature caused by remote earthquakes. The records show that the water temperature changes are consistently following the proces...On the basis of digital records from Tayuan well, we study coseismic effects of water temperature caused by remote earthquakes. The records show that the water temperature changes are consistently following the process of drop-rise-recovery regardless of focal mechanism or epicentral directions. The step amplitude of water temperature increases with the increase of earthquake magnitude, and decreases with the decrease of epicentral distances. They have rather well correlation. Water temperature rising after earthquake is influenced by water level variations. Fi- nally, the mechanisms of coseismic effects of water temperature have been discussed. Preliminary study shows that accelerated convection and mixing of different temperature water in virtue of seismic wave are the main causes of water temperature drops. Seismic wave accelerates water convection, which causes warm water to move up from deeper part of the well and cold water to go down from the upper part. Temperature probe will detect water temperature drops at early stage. After the occurrence of earthquake, as the fluctuation of water level gradually quiets down, water temperature near the probe begins to rise.展开更多
To study the dynamic properties of the concrete subjected to impulsive loading, stress-time curves of concrete in different velocities were measured using split Hopkinson pressure bar (SHPB).Effects of temperature and...To study the dynamic properties of the concrete subjected to impulsive loading, stress-time curves of concrete in different velocities were measured using split Hopkinson pressure bar (SHPB).Effects of temperature and strain rate on the dynamic yield strength and constitutive relation of the con-crete were analyzed. The dynamic mechanical properties of the reinforced concrete are subjected to high strain rates when it is at a relatively low temperature. But with temperature increasing, the temperature softening effect makes the strength of the concrete weaken and the impact toughness of the concrete is saliently relative to strain rate effect. So, strain rate effect, strain hardening and temperature softening work together on the dynamic mechanical capability of concrete and the relation between them is relatively complex.展开更多
The effects of sea surface temperature(SST),cloud radiative and microphysical processes,and diurnal variations on rainfall statistics are documented with grid data from the two-dimensional equilibrium cloud-resolvin...The effects of sea surface temperature(SST),cloud radiative and microphysical processes,and diurnal variations on rainfall statistics are documented with grid data from the two-dimensional equilibrium cloud-resolving model simulations.For a rain rate of higher than 3 mm.h 1,water vapor convergence prevails.The rainfall amount decreases with the decrease of SST from 29℃ to 27℃,the inclusion of diurnal variation of SST,or the exclusion of microphysical effects of ice clouds and radiative effects of water clouds,which are primarily associated with the decreases in water vapor convergence.However,the amount of rainfall increases with the increase of SST from 29℃ to 31℃,the exclusion of diurnal variation of solar zenith angle,and the exclusion of the radiative effects of ice clouds,which are primarily related to increases in water vapor convergence.For a rain rate of less than 3 mm.h 1,water vapor divergence prevails.Unlike rainfall statistics for rain rates of higher than 3 mm.h 1,the decrease of SST from 29℃ to 27℃ and the exclusion of radiative effects of water clouds in the presence of radiative effects of ice clouds increase the rainfall amount,which corresponds to the suppression in water vapor divergence.The exclusion of microphysical effects of ice clouds decreases the amount of rainfall,which corresponds to the enhancement in water vapor divergence.The amount of rainfall is less sensitive to the increase of SST from 29℃ to 31℃ and to the radiative effects of water clouds in the absence of the radiative effects of ice clouds.展开更多
Superoxide dismutase(SOD) is a crucial antioxidant enzyme playing the first defense line in antioxidant pathways against reactive oxygen species in various organisms including marine invertebrates. There exist mainl...Superoxide dismutase(SOD) is a crucial antioxidant enzyme playing the first defense line in antioxidant pathways against reactive oxygen species in various organisms including marine invertebrates. There exist mainly two specific forms, Cu/Zn-SOD(SOD1) and Mn-SOD(SOD2), in eukaryotes. SODs are known to be concurrently modulated by a variety of environmental stressors. By using central composite experimental design and response surface method, the joint effects of water temperature(18–34°C) and copper ion concentration(0.1–1.5 mg/L) on the total SOD activity in the digestive gland of Crassostrea ariakensis were studied. The results showed that the linear effect of temperature was highly significant(P〈0.01), the quadratic effect of temperature was significant(P〈0.05); the linear effect of copper ion concentration was not significant(P〉0.05), while the quadratic effect of copper ion concentration was highly significant(P〈0.01); the interactive effect of temperature and copper ion concentration was not significant(P〉0.05); the effect of temperature was greater than that of copper ion concentration. The model equation of digestive gland SOD enzyme activity towards the two factors of interest was established, with R2 and predictive R2 as high as 0.961 6 and 0.820 7, respectively, suggesting that the goodness-offit to experimental data be very satisfactory, and could be applied to prediction of digestive gland SOD activity in C. ariakensis under the conditions of the experiment. Our results would be conducive to addressing the health of aquatic animals and/or to detecting environmental problems by taking SOD as a potential bioindicator.展开更多
With hydrogen-like impurity(HLI) located in the center of Cs I quantum pseudodot(QPD) and by using the variational method of Pekar type(VMPT), we investigate the first-excited state energy(FESE), excitation en...With hydrogen-like impurity(HLI) located in the center of Cs I quantum pseudodot(QPD) and by using the variational method of Pekar type(VMPT), we investigate the first-excited state energy(FESE), excitation energy and transition frequency of the strongly-coupled bound polaron in the present paper. Temperature effects on bound polaron properties are calculated by employing the quantum statistical theory(QST). According to the present work's numerical results, the FESE, excitation energy and transition frequency decay(amplify) with raising temperature in the regime of lower(higher)temperature. They are decreasing functions of Coulomb impurity potential strength.展开更多
As important atmospheric circulation patterns in Northern Hemisphere(NH),the North Atlantic Oscillation(NAO)and the Western Pacific teleconnection(WP)affect the winter climate in Eurasia.In order to explore the combin...As important atmospheric circulation patterns in Northern Hemisphere(NH),the North Atlantic Oscillation(NAO)and the Western Pacific teleconnection(WP)affect the winter climate in Eurasia.In order to explore the combined effects of NAO and WP on East Asian(EA)temperature,the NAO and WP indices are divided into four phases from 1980−2021:the positive NAO and WP phase(NAO+/WP+),the negative NAO and WP phase(NAO−/WP−),the positive NAO and negative WP phase(NAO+/WP−),the negative NAO and positive WP phase(NAO−/WP+).In the phase of NAO+/WP+,the low geopotential height(GH)stays in north of EA at 50°−80°N;the surface air temperature anomaly(SATA)is 0.8−1℃lower than Southern Asian.In the phase of NAO−/WP−,the center of high temperature and GH locate in the northeast of EA;the cold air spreads to Southern Asia,causing the SATA decreases 1−1.5℃.In the phase of NAO+/WP−,the high GH belt is formed at 55°−80°N.Meanwhile,the center of high SATA locates in the north of Asia that increases 0.8−1.1℃.The cold airflow causes temperature dropping 0.5−1℃in the south of EA.The SATA improves 0.5−1.5℃in south of EA in the phase of NAO−/WP+.The belt of high GH is formed at 25°−50°N,and blocks the cold air which from Siberia.The NAO and WP generate two warped plate pressure structures in NH,and affect the temperature by different pressure configurations.NAO and WP form different GH,and GH acts to block and push airflow by affecting the air pressure,then causes the temperature to be different from the north and south of EA.Finally,the multiple linear regression result shows that NAO and WP are weakened by each other such as the phase of NAO+/WP+and NAO−/WP−.展开更多
In this study,we have examined the effects of exposure to high temperature, carbon inonoxideor a combination of both conditions in a model system,the rat and in industrial workers.In the rat liver, HSP70 mRNA and HSP7...In this study,we have examined the effects of exposure to high temperature, carbon inonoxideor a combination of both conditions in a model system,the rat and in industrial workers.In the rat liver, HSP70 mRNA and HSP70 synthesis were measured by dot hybridization and western blot. The results showed that after a heat stress HSP70 mRNA and its product, HSP70 increased significantly and there was a synergism in the combined effects of high temperature and carbon monoxide exposure on the induction of HSP70 mRNA and HSP70 synthesis. Heat played a major role in this induction. The presence of antibodies to human HSP27, HSP60, HSP70,HSC73, HSP89 αand β in workers exposed to heat, carbon monoxide was also measured by western blot using purified HSPs as antigens. Plasma free amino acids were measured in the saine group of workers. The incidence of antibodies to HSP27 and HSP70 Was significantly higher in the workers working in an environment with extreme heat, and high carbon monoxide ernission than in a control group. The carbon monoxide exposed group showed the highest incidence of antibodies to HSPs. Although our previous results indicated that workers had an insufficient protein intake,plasma free amino acids tended to increase, especially in methionine and tryptophan two kinds of amino acids which are absent from the main stress protein, HSP70.These results suggest that the major problems that these workers may face are how to facilitate the use of plasma free amino acids and reduce the inhibition of synthesis of normal proteins when they are exposed to occupational harmful factors.These resultsalso add new information on the measurement of HSPs as a potential biomonitor to assess whether organisms are experiencing metabolic stress within their environment.展开更多
The kinetics of denitrogenation from liquid steel was studied by using an oxygen-nitrogen analysis system(LECO TC-436) under 1600 degreesC similar to 2813 degreesC conditions. The results show that when [S]=0.005%, ni...The kinetics of denitrogenation from liquid steel was studied by using an oxygen-nitrogen analysis system(LECO TC-436) under 1600 degreesC similar to 2813 degreesC conditions. The results show that when [S]=0.005%, nitrogen removal was controlled by nitrogen transfer in liquid diffusion layer, when [S]=0.012% and 0.140%, it was controlled by both nitrogen transfer in liquid diffusion layer and the chemical reaction at the liquid-gas interface below 2250 degreesC, and by nitrogen transfer in liquid diffusion layer under 2250 degreesC similar to 2813 degreesC conditions. The activation energy E-a was 57 kJ/mol for 0.0050%[S], 95 kJ/mol for 0.012%[S], 165 kJ/mol for 0.140%[S]. The resistance of sulphur on nitrogen removal decreased with the temperature rose, and disappeared at 2630 degreesC. Based on the results obtained, it has been answered why the nitrogen in liquid steel can be decreased rapidly by carbon-oxygen reaction under very high oxygen and sulphur content conditions during the BOF, EAF, VOD and AOD steelmaking processes.展开更多
The influence of high temperature effects on the protrusion of Mach stem in strong shock reflection over a wedge was numerically investigated. A two-dimensional inviscid solver applies finite volume method and unstruc...The influence of high temperature effects on the protrusion of Mach stem in strong shock reflection over a wedge was numerically investigated. A two-dimensional inviscid solver applies finite volume method and unstructured quadrilateral grids were employed to simulate the flow. Theoretical analysis was also conducted to understand the phenomenon. Both numerical and theoretical results indicate a wall-jet penetrating forward is responsible for the occurrence of Mach stem protrusion. The protrusion degree seems to depend on the thermal energy buffer capacity of the testing gas. Approaches to increase the energy buffer capacity, such as vibrational relaxation, molecular dissociation, and increase of frozen heat caoacitv, all tend to escalate the orotrusion effect.展开更多
The temperature and the size dependences of the self-trapping energy of a polaron in a GaAs parabolic quantum dot are investigated by the second order Rayleigh-Schrodinger perturbation method using the framework of th...The temperature and the size dependences of the self-trapping energy of a polaron in a GaAs parabolic quantum dot are investigated by the second order Rayleigh-Schrodinger perturbation method using the framework of the effective mass approximation. The numerical results show that the self-trapping energies of polaron in GaAs parabolic quantum dots shrink with the enhancement of temperature and the size of the quantum dot. The results also indicate that the temperature effect becomes obvious in small quantum dots展开更多
Bi_2Te_3 thin films and GeTe/B_2Te_3 superlattices of different thicknesses are prepared on the silicon dioxide substrates by magnetron sputtering technique and thermally annealed at 573 K for 30 min. Thermoelectric...Bi_2Te_3 thin films and GeTe/B_2Te_3 superlattices of different thicknesses are prepared on the silicon dioxide substrates by magnetron sputtering technique and thermally annealed at 573 K for 30 min. Thermoelectric(TE)measurements indicate that optimal thickness and thickness ratio improve the TE performance of Bi_2Te_3 thin films and GeTe/B_2Te_3 superlattices, respectively. High TE performances with figure-of-merit(ZT) values as high as 1.32 and 1.56 are achieved at 443 K for 30 nm and 50 nm Bi_2Te_3 thin films, respectively. These ZT values are higher than those of p-type Bi_2Te_3 alloys as reported. Relatively high ZT of the GeTe/B_2Te_3 superlattices at 300-380 K were 0.62-0.76. The achieved high ZT value may be attributed to the unique nano-and microstructures of the films,which increase phonon scattering and reduce thermal conductivity. The results indicate that Bi_2Te_3-based thin films can serve as high-performance materials for applications in TE devices.展开更多
基金supported by National Natural Science Foundation of China(Nos.U1967206 and 12275071)National Key R&D Program of China(No.2017YFE0301201)。
文摘The effects of impurities on ion temperature gradient(ITG)driven turbulence transport in tokamak core plasmas are investigated numerically via global simulations of microturbulence with carbon impurities and adiabatic electrons.The simulations use an extended fluid code(ExFC)based on a four-field gyro-Landau-fluid(GLF)model.The multispecies form of the normalized GLF equations is presented,which guarantees the self-consistent evolution of both bulk ions and impurities.With parametric profiles of the cyclone base case,well-benchmarked ExFC is employed to perform simulations focusing on different impurity density profiles.For a fixed temperature profile,it is found that the turbulent heat diffusivity of bulk ions in a quasi-steady state is usually lower than that without impurities,which is contrary to the linear and quasilinear predictions.The evolutions of the temperature gradient and heat diffusivity exhibit a fast relaxation process,indicating that the destabilization of the outwardly peaked impurity profile is a transient state response.Furthermore,the impurity effects from different profiles can obviously influence the nonlinear critical temperature gradient,which is likely to be dominated by linear effects.These results suggest that the improvement in plasma confinement could be attributed to the impurities,most likely through adjusting both heat diffusivity and the critical temperature gradient.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.U2230401,U1930401,and 12004048)the National Key Research and Development Program of China (Grant No.2021YFB3501503)+1 种基金the Science Challenge Project (Grant No.TZ2018002)the Foundation of LCP。
文摘Hydride precipitation in zirconium cladding materials can damage their integrity and durability.Service temperature and material defects have a significant effect on the dynamic growth of hydrides.In this study,we have developed a phasefield model based on the assumption of elastic behaviour within a specific temperature range(613 K-653 K).This model allows us to study the influence of temperature and interfacial effects on the morphology,stress,and average growth rate of zirconium hydride.The results suggest that changes in temperature and interfacial energy influence the length-to-thickness ratio and average growth rate of the hydride morphology.The ultimate determinant of hydride orientation is the loss of interfacial coherency,primarily induced by interfacial dislocation defects and quantifiable by the mismatch degree q.An escalation in interfacial coherency loss leads to a transition of hydride growth from horizontal to vertical,accompanied by the onset of redirection behaviour.Interestingly,redirection occurs at a critical mismatch level,denoted as qc,and remains unaffected by variations in temperature and interfacial energy.However,this redirection leads to an increase in the maximum stress,which may influence the direction of hydride crack propagation.This research highlights the importance of interfacial coherency and provides valuable insights into the morphology and growth kinetics of hydrides in zirconium alloys.
基金funded by the Special Fund for Agro-scientific Research in the Public Interest of China (201403031)the China Agriculture Research System (CARS-22)+2 种基金the National Key Research and Development Program of China (2017YFD0201802, 2017YFD0201701)he National Natural Science Foundation of China (31672019, 31371947)the Beijing Natural Science Foundation, China (6172030)
文摘The armyworm Mythimna roseilinea(Walker) is a major pest of grain crops in South China. So far little is known about its basic biology and ecology, making prediction of population dynamics difficult. This study examined the relationships of individual development and population growth with temperature based on an age-stage, two-sex life table of M. roseilinea reared on maize in the laboratory at 18, 21, 24, 27 and 30℃. The highest values of net reproductive rate(R_0) and fecundity were observed at 21 and 24℃, respectively. Both the intrinsic rate of increase(r) and finite rate of increase(λ) increased significantly and mean generation time(T) decreased significantly with increasing temperature. M. roseilinea was able to develop, survive and lay eggs at all temperature regimes tested. Development rates of the egg, larval, pupal, as well as the whole pre-oviposition stages had a positive linear relationship with temperature. The calculated development threshold temperatures of egg, larval, pupal, pre-oviposition and total pre-oviposition stages were 13.29, 8.39, 14.35, 7.42, and 12.24℃, respectively, and their effective accumulated temperatures were 63.59, 445.00, 211.11, 89.02, and 698.95 degree-days, respectively. These results provide insight into temperature-based phenology and population ecology of this insect pest and will allow population prediction and management available in the field.
基金supported by the Knowledge Innovation Program of the Chinese Academy Sciences (No. KZCX1-YW-08-02-01)National High-tech Research and development Program of China(No. 2006AA10Z227)
文摘At present, the most researches on the protected effect of shelterbelt are on the basis of the two scales of forest belts and networks. However, with the further research on the global environmental change, more attention was paid to the regional climate effect of shelterbelt. In present study, we analyzed the temperature effect of the shelterbelt at regional scale by using the land surface temperature (LST) data from the moderate resolution imaging spectroradiometer (MODIS) at Yushu, Nong'an, Dehui, and Fuyu in Jilin Province of China from March to October in 2008. Results show that the shelterbelt can increase the soil temperature of the protected farmland as compared with no shelterbelt zone, with the increment of 0.57oC per day in fine shelterbelt and 0.38oC per day in the normal shelterbelt. Moreover, the correlation analysis of the air temperature, precipitation and the soil type and the shelterbelt effect shows that the air temperature and precipitation are negatively correlated with the shelterbelt effects, that is, the more the temperature and precipitation are, the less the effect produced. While the impact of the soil types on the shelterbelt's effect is not very obvious as a whole. This paper draws significance in terms of analyzing the effects of the shelterbelt on the soil temperature at regional scale utilizing the remotely sensed data and GIS technique.
基金supported by the Ph.D.program of Institute of Tibetan Plateau Research,ITPCAS
文摘Seasonal variation of stable isotopes in precipitation of Kathmandu Valley on the southem slope of Himalaya was carried out to understand the controlling mechanism of amount and temperature effect on the basis of one year stable isotope data from 2010 to 2011. Highly depleted isotope values in major rainy period are obtained just after the onset of precipitation in summer, which ac- counts for "amount effect" due to saturation isotopic compositions in high moisture condition, whereas, the higher values in winter are indicative to regional vapors (temperature effect) recycling of various sources. An abrupt depletion of isotope values in mid- June, indicates the onset date of monsoon precipitation, by the replacement of winter air mass with southem monsoon. Thus, pre- cipitation isotopes are a tool revealing the onset date of summer monsoon and temporal features of variability, in local and regional monsoons precipitations. A comparison of long term monthly values of 5180, temperature, and precipitation with GNIP 6180 data shows the temporal variations of stable isotopes are mostly controlled by amount and temperature effects. During summer mon- soon, the amount effects are stronger for high values of precipitation (R=0.7) and altitude effect appears for low moisture in late rainy season, thus from December to June (winter to pre-monsoon) the controlling features of isotopes remains under the temper- ature effect. A temporal rate of temperature effect is derived as 0.04%0 per year which indicates a dry signal of atmospheric condition and a temperature relation 5180=(0.371±0.08)T+(0.156±0.05) is obtained from this analysis. The meteoric water lines of Kathmandu before and after monsoon onset of 2011, are found as 5D=(4.36±0.3)5180+(15.66±1.2) and 5D=(6.91±0.2)S180-(7.92±2.26) from lab samples result, and 5D=9.25180+11.725 and 5D=8.535180+16.65 from GNIP data, which lacks the consistency both for slopes and intercepts values for the study period. The mean lapse rate values of δ18O and δD from GNIP data are obtained as -0.002‰/m and -0.015 ‰/m, which indicate the altitudinal effects in regional precipitation of the southern slope of Himalayas. This study estimates new stable isotopes data in recent precipitation using simple methodology which can be important for regional precipitation monitoring systems, environmental change and paleo-climatic studies.
基金financially supported by the International Science&Technology Cooperation Program of China(Grant No.2012DFA60760)
文摘Rock is generally complex and heterogeneous,therefore the heterogeneity effects of effective stress and temperature on permeability should be taken into account.In this study,two-part Hooke’s model(TPHM) is introduced to understand the influences of effective stress and temperature on permeability of soft and hard parts(two parts) of rock based on coupling thermo-hydro-mechanical tests.Under a fixed temperature level(25 ℃.35 ℃.50 ℃.65 ℃.80 ℃.90 ℃ and 95 ℃).the tests were carried out in a conventional triaxial system whereas the confining pressure was remained at 50 MPa.and the pore pressure was increased to the specified levels step by step.i.e.8 MPa,18 MPa.28 MPa.38 MPa.41 MPa,44 MPa.46 MPa and 48 MPa.The temperature-dependent relationships for two parts permeabilities are proposed on the basis of the initial test results.We point out that temperature of 65 ℃-90 ℃ is the threshold for the development of CO2-plume geothermal(CPC) reservoir sandstone cracking under low effective stress(2-9 MPa) based on the relationship between temperature and soft part permeability.Furthermore,we discuss the effect of temperature on the two parts in the rock.The results indicate that as the temperature increases from 25 ℃ to 65 ℃.the flow channel in the hard part has a stronger response to temperature than that in the soft part at a fixed effective stress level,which is opposite to the situation of effective stress.Considering that natural rock is generally heterogeneous with non-uniform pore structure,we suggest a physical interpretation of the phenomenon that before the thermal cracking threshold the two parts have different responses to temperature.
文摘Temperature front (TF) is one of the important features in the Yellow Sea, which forms in spring,thrives in summer, and fades in autumn as thermocline declines. TF intensity |ST| is defined to describe the distribution of TF. Based on the MASNUM wave-tide-circulation coupled model, temperature distribution in the Yellow Sea was simulated with and without tidal effects. Along 36°N, distribution of TF from the simulated results are compared with the observations, and a quantitative analysis is introduced to evaluate the tidal effects on the forming and maintaining processes of the TF. Tidal mixing and the circulation structure adapting to it are the main causes of the TF.
文摘Effects of temperature and drying and wetting alternation(DWA)on ammonium fixation in manured loessial soil were studied by means of Batch Equilibrium with Varying concentration solutions of ammonium chloride,ammonium fixation time,and soil clay contents.The purpose of the research was to find out the pattern of ammonium fixation ted by the varying factors.The results showed a remarkable variation in ammonium fixation.Fixed ammonium increased with temperature and treatments of DWA.The ammonium fixation in manured loessial soil was characterized by the effect of temperature and DWA.
基金Supported by National Natural Science Foundation of China under Grant No.10747002Research Funds from Qufu Normal University under Grant No.XJZ200839
文摘On the condition of electric-LO phonon strong coupling in a parabolic quantum dot,we obtain theeigenenergy and the eigenfunctions of the ground state and the first-excited state using the variational method ofPekar type.This system in a quantum dot may be employed as a two-level quantum system-qubit.When the electronis in the superposition state of the ground state and the first-excited state,we obtain the time evolution of the electrondensity.The relations of the probability density of electron on the temperature and the electron-LO-phonon couplingconstant and the relations of the period of oscillation on the temperature,the electron-LO-phonon coupling constant,the Coulomb binding parameter and the confinement length are derived.The results show that the probability densityof electron oscillates with a period when the electron is in the superposition state of the ground and the first-excitedstate,and show that there are different laws that the probability density of electron and the period of oscillation changewith the temperature and the electron-LO-phonon coupling constant when the temperature is lower or higher.Andit is obtained that the period of oscillation decreases with increasing the Coulomb bound potential and increases withincreasing the confinement length not only at lower temperatures but also at higher temperatures.
基金National Natural Science Foundation of China(40372131)the Key Projects Required by National 10th Five-year Plan(2004BA601B01-02-02).
文摘On the basis of digital records from Tayuan well, we study coseismic effects of water temperature caused by remote earthquakes. The records show that the water temperature changes are consistently following the process of drop-rise-recovery regardless of focal mechanism or epicentral directions. The step amplitude of water temperature increases with the increase of earthquake magnitude, and decreases with the decrease of epicentral distances. They have rather well correlation. Water temperature rising after earthquake is influenced by water level variations. Fi- nally, the mechanisms of coseismic effects of water temperature have been discussed. Preliminary study shows that accelerated convection and mixing of different temperature water in virtue of seismic wave are the main causes of water temperature drops. Seismic wave accelerates water convection, which causes warm water to move up from deeper part of the well and cold water to go down from the upper part. Temperature probe will detect water temperature drops at early stage. After the occurrence of earthquake, as the fluctuation of water level gradually quiets down, water temperature near the probe begins to rise.
基金Supported by National Natural Science Foundation of China(No.10602048)
文摘To study the dynamic properties of the concrete subjected to impulsive loading, stress-time curves of concrete in different velocities were measured using split Hopkinson pressure bar (SHPB).Effects of temperature and strain rate on the dynamic yield strength and constitutive relation of the con-crete were analyzed. The dynamic mechanical properties of the reinforced concrete are subjected to high strain rates when it is at a relatively low temperature. But with temperature increasing, the temperature softening effect makes the strength of the concrete weaken and the impact toughness of the concrete is saliently relative to strain rate effect. So, strain rate effect, strain hardening and temperature softening work together on the dynamic mechanical capability of concrete and the relation between them is relatively complex.
基金Project supported by the National Basic Research Program of China (Grant No. 2012CB417201)the National Natural Science Foundation of China (Grant Nos. 41075034,40930950,40975034,and 41075044)
文摘The effects of sea surface temperature(SST),cloud radiative and microphysical processes,and diurnal variations on rainfall statistics are documented with grid data from the two-dimensional equilibrium cloud-resolving model simulations.For a rain rate of higher than 3 mm.h 1,water vapor convergence prevails.The rainfall amount decreases with the decrease of SST from 29℃ to 27℃,the inclusion of diurnal variation of SST,or the exclusion of microphysical effects of ice clouds and radiative effects of water clouds,which are primarily associated with the decreases in water vapor convergence.However,the amount of rainfall increases with the increase of SST from 29℃ to 31℃,the exclusion of diurnal variation of solar zenith angle,and the exclusion of the radiative effects of ice clouds,which are primarily related to increases in water vapor convergence.For a rain rate of less than 3 mm.h 1,water vapor divergence prevails.Unlike rainfall statistics for rain rates of higher than 3 mm.h 1,the decrease of SST from 29℃ to 27℃ and the exclusion of radiative effects of water clouds in the presence of radiative effects of ice clouds increase the rainfall amount,which corresponds to the suppression in water vapor divergence.The exclusion of microphysical effects of ice clouds decreases the amount of rainfall,which corresponds to the enhancement in water vapor divergence.The amount of rainfall is less sensitive to the increase of SST from 29℃ to 31℃ and to the radiative effects of water clouds in the absence of the radiative effects of ice clouds.
基金The Guangdong Province Education Department under contract No.GCZX-A0909the Guangdong Province Ocean and Fisheries Science & Technology Extension Project under contract No.20120980+1 种基金the Guangdong Province Industry-University-Science Partnership Project under contract No.20110908the Science&Technology Project of Huaiyin Normal University under contract No.WH0031
文摘Superoxide dismutase(SOD) is a crucial antioxidant enzyme playing the first defense line in antioxidant pathways against reactive oxygen species in various organisms including marine invertebrates. There exist mainly two specific forms, Cu/Zn-SOD(SOD1) and Mn-SOD(SOD2), in eukaryotes. SODs are known to be concurrently modulated by a variety of environmental stressors. By using central composite experimental design and response surface method, the joint effects of water temperature(18–34°C) and copper ion concentration(0.1–1.5 mg/L) on the total SOD activity in the digestive gland of Crassostrea ariakensis were studied. The results showed that the linear effect of temperature was highly significant(P〈0.01), the quadratic effect of temperature was significant(P〈0.05); the linear effect of copper ion concentration was not significant(P〉0.05), while the quadratic effect of copper ion concentration was highly significant(P〈0.01); the interactive effect of temperature and copper ion concentration was not significant(P〉0.05); the effect of temperature was greater than that of copper ion concentration. The model equation of digestive gland SOD enzyme activity towards the two factors of interest was established, with R2 and predictive R2 as high as 0.961 6 and 0.820 7, respectively, suggesting that the goodness-offit to experimental data be very satisfactory, and could be applied to prediction of digestive gland SOD activity in C. ariakensis under the conditions of the experiment. Our results would be conducive to addressing the health of aquatic animals and/or to detecting environmental problems by taking SOD as a potential bioindicator.
基金Project supported by the National Natural Science Foundation of China(Grant No.11464033)
文摘With hydrogen-like impurity(HLI) located in the center of Cs I quantum pseudodot(QPD) and by using the variational method of Pekar type(VMPT), we investigate the first-excited state energy(FESE), excitation energy and transition frequency of the strongly-coupled bound polaron in the present paper. Temperature effects on bound polaron properties are calculated by employing the quantum statistical theory(QST). According to the present work's numerical results, the FESE, excitation energy and transition frequency decay(amplify) with raising temperature in the regime of lower(higher)temperature. They are decreasing functions of Coulomb impurity potential strength.
基金The National Key Research and Development Program of China under contract No.2022YFE0140500the National Natural Science Foundation of China under contract Nos 41821004 and 42130406+2 种基金the National Natural Science Foundation of China-Shandong Joint Fund under contract No.U1906215the Open Fund of Key Laboratory of Ocean Circulation and Waves,Chinese Academy of Sciences under contract No.KLOCW2003the Project of Doctoral Found of Qingdao University of Science and Technology under contract No.210010022746.
文摘As important atmospheric circulation patterns in Northern Hemisphere(NH),the North Atlantic Oscillation(NAO)and the Western Pacific teleconnection(WP)affect the winter climate in Eurasia.In order to explore the combined effects of NAO and WP on East Asian(EA)temperature,the NAO and WP indices are divided into four phases from 1980−2021:the positive NAO and WP phase(NAO+/WP+),the negative NAO and WP phase(NAO−/WP−),the positive NAO and negative WP phase(NAO+/WP−),the negative NAO and positive WP phase(NAO−/WP+).In the phase of NAO+/WP+,the low geopotential height(GH)stays in north of EA at 50°−80°N;the surface air temperature anomaly(SATA)is 0.8−1℃lower than Southern Asian.In the phase of NAO−/WP−,the center of high temperature and GH locate in the northeast of EA;the cold air spreads to Southern Asia,causing the SATA decreases 1−1.5℃.In the phase of NAO+/WP−,the high GH belt is formed at 55°−80°N.Meanwhile,the center of high SATA locates in the north of Asia that increases 0.8−1.1℃.The cold airflow causes temperature dropping 0.5−1℃in the south of EA.The SATA improves 0.5−1.5℃in south of EA in the phase of NAO−/WP+.The belt of high GH is formed at 25°−50°N,and blocks the cold air which from Siberia.The NAO and WP generate two warped plate pressure structures in NH,and affect the temperature by different pressure configurations.NAO and WP form different GH,and GH acts to block and push airflow by affecting the air pressure,then causes the temperature to be different from the north and south of EA.Finally,the multiple linear regression result shows that NAO and WP are weakened by each other such as the phase of NAO+/WP+and NAO−/WP−.
文摘In this study,we have examined the effects of exposure to high temperature, carbon inonoxideor a combination of both conditions in a model system,the rat and in industrial workers.In the rat liver, HSP70 mRNA and HSP70 synthesis were measured by dot hybridization and western blot. The results showed that after a heat stress HSP70 mRNA and its product, HSP70 increased significantly and there was a synergism in the combined effects of high temperature and carbon monoxide exposure on the induction of HSP70 mRNA and HSP70 synthesis. Heat played a major role in this induction. The presence of antibodies to human HSP27, HSP60, HSP70,HSC73, HSP89 αand β in workers exposed to heat, carbon monoxide was also measured by western blot using purified HSPs as antigens. Plasma free amino acids were measured in the saine group of workers. The incidence of antibodies to HSP27 and HSP70 Was significantly higher in the workers working in an environment with extreme heat, and high carbon monoxide ernission than in a control group. The carbon monoxide exposed group showed the highest incidence of antibodies to HSPs. Although our previous results indicated that workers had an insufficient protein intake,plasma free amino acids tended to increase, especially in methionine and tryptophan two kinds of amino acids which are absent from the main stress protein, HSP70.These results suggest that the major problems that these workers may face are how to facilitate the use of plasma free amino acids and reduce the inhibition of synthesis of normal proteins when they are exposed to occupational harmful factors.These resultsalso add new information on the measurement of HSPs as a potential biomonitor to assess whether organisms are experiencing metabolic stress within their environment.
文摘The kinetics of denitrogenation from liquid steel was studied by using an oxygen-nitrogen analysis system(LECO TC-436) under 1600 degreesC similar to 2813 degreesC conditions. The results show that when [S]=0.005%, nitrogen removal was controlled by nitrogen transfer in liquid diffusion layer, when [S]=0.012% and 0.140%, it was controlled by both nitrogen transfer in liquid diffusion layer and the chemical reaction at the liquid-gas interface below 2250 degreesC, and by nitrogen transfer in liquid diffusion layer under 2250 degreesC similar to 2813 degreesC conditions. The activation energy E-a was 57 kJ/mol for 0.0050%[S], 95 kJ/mol for 0.012%[S], 165 kJ/mol for 0.140%[S]. The resistance of sulphur on nitrogen removal decreased with the temperature rose, and disappeared at 2630 degreesC. Based on the results obtained, it has been answered why the nitrogen in liquid steel can be decreased rapidly by carbon-oxygen reaction under very high oxygen and sulphur content conditions during the BOF, EAF, VOD and AOD steelmaking processes.
文摘The influence of high temperature effects on the protrusion of Mach stem in strong shock reflection over a wedge was numerically investigated. A two-dimensional inviscid solver applies finite volume method and unstructured quadrilateral grids were employed to simulate the flow. Theoretical analysis was also conducted to understand the phenomenon. Both numerical and theoretical results indicate a wall-jet penetrating forward is responsible for the occurrence of Mach stem protrusion. The protrusion degree seems to depend on the thermal energy buffer capacity of the testing gas. Approaches to increase the energy buffer capacity, such as vibrational relaxation, molecular dissociation, and increase of frozen heat caoacitv, all tend to escalate the orotrusion effect.
文摘The temperature and the size dependences of the self-trapping energy of a polaron in a GaAs parabolic quantum dot are investigated by the second order Rayleigh-Schrodinger perturbation method using the framework of the effective mass approximation. The numerical results show that the self-trapping energies of polaron in GaAs parabolic quantum dots shrink with the enhancement of temperature and the size of the quantum dot. The results also indicate that the temperature effect becomes obvious in small quantum dots
文摘Bi_2Te_3 thin films and GeTe/B_2Te_3 superlattices of different thicknesses are prepared on the silicon dioxide substrates by magnetron sputtering technique and thermally annealed at 573 K for 30 min. Thermoelectric(TE)measurements indicate that optimal thickness and thickness ratio improve the TE performance of Bi_2Te_3 thin films and GeTe/B_2Te_3 superlattices, respectively. High TE performances with figure-of-merit(ZT) values as high as 1.32 and 1.56 are achieved at 443 K for 30 nm and 50 nm Bi_2Te_3 thin films, respectively. These ZT values are higher than those of p-type Bi_2Te_3 alloys as reported. Relatively high ZT of the GeTe/B_2Te_3 superlattices at 300-380 K were 0.62-0.76. The achieved high ZT value may be attributed to the unique nano-and microstructures of the films,which increase phonon scattering and reduce thermal conductivity. The results indicate that Bi_2Te_3-based thin films can serve as high-performance materials for applications in TE devices.