In this study,the characteristics of azimuthally asymmetric equivalent potential temperature(θ_(e))distributions in the outer core of tropical cyclones(TCs)encountering weak and strong vertical wind shear are examine...In this study,the characteristics of azimuthally asymmetric equivalent potential temperature(θ_(e))distributions in the outer core of tropical cyclones(TCs)encountering weak and strong vertical wind shear are examined using a Lagrangian trajectory method.Evaporatively forced downdrafts in the outer rainbands can transport low-entropy air downward,resulting in the lowestθ_(e)in the downshear-left boundary layer.Quantitative estimations ofθ_(e)recovery indicate that air parcels,especially those originating from the downshear-left outer core,can gradually revive from a low entropy state through surface enthalpy fluxes as the parcels move cyclonically.As a result,the maximumθ_(e)is observed in the downshear-right quadrant of a highly sheared TC.The trajectory analyses also indicate that parcels that move upward in the outer rainbands and those that travel through the inner core due to shear make a dominant contribution to the midlevel enhancement ofθ_(e)in the downshear-left outer core.In particular,the former plays a leading role in suchθ_(e)enhancements,while the latter plays a secondary role.As a result,moist potential stability occurs in the middle-to-lower troposphere in the downshear-left outer core.展开更多
We have applied strong coupling unitary transformation method combined with Bose–Einstein statistical law to investigate magnetopolaron energy level temperature effects in halogen ion crystal quantum wells.The obtain...We have applied strong coupling unitary transformation method combined with Bose–Einstein statistical law to investigate magnetopolaron energy level temperature effects in halogen ion crystal quantum wells.The obtained results showed that under magnetic field effect,magnetopolaron quasiparticle was formed through the interaction of electrons and surrounding phonons.At the same time,magnetopolaron was influenced by phonon temperature statistical law and important energy level shifts down and binding energy increases.This revealed that lattice temperature and magnetic field could easily affect magnetopolaron and the above results could play key roles in exploring thermoelectric conversion and conductivity of crystal materials.展开更多
A novel emissive probe consisting of an oxide cathode coating is developed to achieve a low operating temperature and long service life.The properties of the novel emissive probe are investigated in detail,in comparis...A novel emissive probe consisting of an oxide cathode coating is developed to achieve a low operating temperature and long service life.The properties of the novel emissive probe are investigated in detail,in comparison with a traditional tungsten emissive probe,including the operating temperature,the electron emission capability and the plasma potential measurement.Studies of the operating temperature and electron emission capability show that the tungsten emissive probe usually works at a temperature of 1800 K-2200 K while the oxide cathode emissive probe can function at about 1200 K-1400 K.In addition,plasma potential measurements using the oxide cathode emissive probe with different techniques have been accomplished in microwave electron cyclotron resonance plasmas with different discharge powers.It is found that a reliable plasma potential can be obtained using the improved inflection point method and the hot probe with zero emission limit method,while the floating point method is invalid for the oxide cathode emissive probe.展开更多
In the Northwest Pacific Ocean, the squid jigging fisheries from China, Japan and other countries and regions have targeted the west winter-spring cohort of neon flying squid(Ommastrephes bartramii) from August to N...In the Northwest Pacific Ocean, the squid jigging fisheries from China, Japan and other countries and regions have targeted the west winter-spring cohort of neon flying squid(Ommastrephes bartramii) from August to November since the 1970 s. This squid is a short-lived ecological opportunist with a life-span of about one year,and its population is labile and recruitment variability is driven by the environment or climate change. This variability provides a challenge for ones to forecast the key habitats affected by climate change. The catch data of O. bartramii from Chinese squid jigging fishery and the satellite-derived sea surface temperature(SST) data are used in the Northwest Pacific Ocean from August to November of 1998 to 2004, the SST preferences of O.bartramii corresponding to high values of catch per fishing day(CPUE) are determined and monthly potential habitats are predicted using a histogram analysis of the SST data. The possible changes in the potential habitats of O. bartramii in the Northwest Pacific Ocean are estimated under four climate change scenarios based on the Fourth Assessment Report(AR4) of the Intergovernmental Panel on Climate Change, i.e., 0.5, 1, 2 and 4°C increases in the SST because of the climate change. The results reveal an obvious poleward shift of the potential habitats of O. bartramii in the Northwest Pacific Ocean.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
Compared to potential temperature (θ) in the dry atmosphere and equivalent potential temperature (θc) in the saturated atmosphere, generalized potential tem- perature (θ") has already proven a better thermod...Compared to potential temperature (θ) in the dry atmosphere and equivalent potential temperature (θc) in the saturated atmosphere, generalized potential tem- perature (θ") has already proven a better thermodynamic parameter in describing the non-uniformly saturated real atmosphere. To add otherwise absent graphic explanations, this paper first presents the physical definition of θ through a tephigram. Then, the utility of the measurement in identifying and forecasting the locations of precipita- tion maxima and heat wave areas with diagnostic com- parison studies and traditionally used thermodynamic parameters is shown.展开更多
A regional potential vorticity(PV)intrusion(PVI)(RPVI)index,defined as the sum of the numbers of grids containing PVI within a certain area for each day,is used to reflect the day-to-day PVI variability over northeast...A regional potential vorticity(PV)intrusion(PVI)(RPVI)index,defined as the sum of the numbers of grids containing PVI within a certain area for each day,is used to reflect the day-to-day PVI variability over northeastern China during winter from 1979 to 2016.The synoptic-scale PVI variations and resultant surface air temperature(SAT)anomalies are identified by comparing the high and low RPVI index cases.In high(low)RPVI cases,significantly strong positive(negative)PV anomalies are found in the stratospheric midlatitudes,which intrude downward mostly within 90°–110°E into the upper troposphere to reach around 300 hPa and extend eastward to the east of 120°E,forcing an anomalous cyclonic(anticyclonic)circulation in the middle and lower troposphere over East Asia,with the anomalous northerlies(southerlies)of the forced lower-tropospheric cyclone(anticyclone)leading to significant negative(positive)SAT anomalies of less(greater)than-0.9°C(0.9°C),especially over northeastern China.In the stratosphere,the positive(negative)midlatitude PV anomalies over northern China are actually associated with a weakening(strengthening)of the polar vortex over the Eurasian continent for the high(low)RPVI cases,resulting mostly from positive(negative)barotropic vorticity anomalies associated with static stability due to the meridional shear of anomalous zonal winds on the southern side of the anomalous Eurasian anticyclone(cyclone).展开更多
The energy budgets of the ocean play a crucial role in the analysis of climate change. Potential temperature is traditionally used as a conservative quantity to express variations associated with “heat” in oceanogra...The energy budgets of the ocean play a crucial role in the analysis of climate change. Potential temperature is traditionally used as a conservative quantity to express variations associated with “heat” in oceanography, such as the heat content and heat transport. However, potential temperature is usually not conserved during turbulent mixing, so the use of conservative temperature is more accurate. Based on climatological simulations under the modern and Last Glacial Maximum (LGM;~21 ka;ka=thousand years ago), as well as a transient climate simulation of the past 22 000 years, we quantify the errors induced by the neglect of the non-conservation of potential temperature in paleo-climate research for the first time. The temperature error reaches 0.9℃ near the coasts aff ected by river discharges but is much smaller in the open oceans, typically 0.03°C above the main thermocline and less than 0.01℃ elsewhere. The error of the ocean heat content (OHC) is roughly 3×10^22 J and is relatively steady over the past 22 000 years. However, the OHC increases to six times the original value during the last glacial termination from 20 ka to 7 ka. As a result, the relative OHC error decreases from 1.2% in the LGM climate to 0.14% in the modern climate. The error of the ocean meridional heat transport (OMHT) is generally smaller than 0.005 PW (1 PW=10 15 W), with very small temporal variations (typically 0.000 4 PW), and induces a relative OMHT error of typically 0.3% over the past 22 000 years. Therefore, the neglect of the non-conservation of potential temperature induces a relative error of generally less than 1% in the analyses of basin-scale climate variations.展开更多
Generally speaking, the quark propagator is dependent on the quark chemical potential in the dense quantum chromodynamics (QCD). By means of the generating functional method, we prove that the quark propagator actua...Generally speaking, the quark propagator is dependent on the quark chemical potential in the dense quantum chromodynamics (QCD). By means of the generating functional method, we prove that the quark propagator actually depends on p4 + iμ from the first principle of QCD. The relation between quark number density and quark condensate is discussed by analyzing their singularities. It is concluded that the quark number density has some singularities at certain # when T = 0, and the variations of the quark number density as well as the quark condensate are located at the same point. In other words, at a certain # the quark number density turns to nonzero, while the quark condensate begins to decrease from its vacuum value.展开更多
Enhancing the piezoelectricity of CaBi_(4)Ti_(4)O_(15)(CBT)ceramics is crucial for improving their application potential in high-temperature piezoelectric devices.Here,we propose a strategy involving the introduction ...Enhancing the piezoelectricity of CaBi_(4)Ti_(4)O_(15)(CBT)ceramics is crucial for improving their application potential in high-temperature piezoelectric devices.Here,we propose a strategy involving the introduction of larger Na/Bi ions at the A-site,effectively inhibiting the tilt of oxygen octahedra and flattening the potential energy profile.This flattening enhances the variation in polarization under external fields.Concurrently,substituting Nb/Mn at the B-site increases the deviation between positive and negative ionic centers,leading to stronger spontaneous polarization,while the induced defect dipoles restrict oxygen vacancy migration and increase the direct current resistivity(ρ_(dc)).The flattened potential energy profile and increased spontaneous polarization significantly enhance the overall performance of cBT ceramics,with the piezoelectric constant(d_(33))reaching 25 pC/N when the Curie temperature(Tc)=752℃.Piezoresponse force microscopy(PFM)and transmission electron microscopy(TEM)revealed submicron-long rectangular domains and nanoscale domains in the modified composition,indicating a high density of domain walls.This study presents an effective approach for enhancing the piezoelectric properties of bismuth layered-structured ferroelectrics(BLSFs),thereby improving the application potential of BLSFsathightemperatures.展开更多
The key zones of returning farmland to forestland and grassland in Ningxia were studied. By using the "stepwise revised method",the climate productive potential,light and temperature productive potential in the zone...The key zones of returning farmland to forestland and grassland in Ningxia were studied. By using the "stepwise revised method",the climate productive potential,light and temperature productive potential in the zone in recent 50 years were counted. The light and temperature productive potential of corn in Ningxia irrigated area,the central arid zone and the southern mountain area presented the linear increase trend. But when considered the climate productive potentials of light,temperature and water,the numerical value was very low because of the scarce rainfall,and no agriculture without the irrigation. The light and temperature productive potential,climate productive potential of winter wheat in the central arid zone had no significant trend,but the variation range of climate productive potential was very big. The light and temperature productive potential of winter wheat in the southern mountain area had no significant variation trend,and the climate productive potential presented the weak decline trend. It illustrated that the productive of winter wheat was greatly restricted by the water content. By using the meteorological factor data which were simulated by RegCM3-WOFOST/LINGRA coupled model,the future climate productive potentials of winter wheat in the central south of Ningxia was counted. They both presented the weak increase trend. It illustrated that the climate in Ningxia was favorable to improve the yield of winter wheat after returning farmland to forestland.展开更多
A suitable carburized microstructure with fine granular dispersed carbides in hypereutectoid zone,ultra fine martensite in matrix and recrystallized austenite to be refined to the grain size of 12~14 has been obtaine...A suitable carburized microstructure with fine granular dispersed carbides in hypereutectoid zone,ultra fine martensite in matrix and recrystallized austenite to be refined to the grain size of 12~14 has been obtained by a new process,which is a high carbon concentration carburizing with rare earth element at low temperature(860~880℃)in a discontinuous gas carburization furnace.There was not much difference for the microstructure in eutectic zone between this and conventional process.Forming mechanism of granular carbides has been also studied in this paper.展开更多
The effects of marine environmental factors-temperature (T), dissolved oxygen (DO), salinity (S) and pH--on the oxidation-reduction potential (ORP) of natural seawater were studied in laboratory. The results s...The effects of marine environmental factors-temperature (T), dissolved oxygen (DO), salinity (S) and pH--on the oxidation-reduction potential (ORP) of natural seawater were studied in laboratory. The results show an indistinct relationship between these four factors and the ORE but they did impact the ORP. Common mathematical methods were not applicable for describing the relationship. Therefore, a grey relational analysis (GRA) method was developed. The degrees of correlation were calculated according to GILA and the values of T, pH, DO and S were 0.744, 0.710, 0.692 and 0.690, respectively. From these values, the relations of these factors to the ORP could be described and evaluated, and those of T and pH were relatively major. In general, ORP is influenced by the synergic effect of T, DO, pH and S, with no single factor having an outstanding role.展开更多
The uniformity principle of temperature difference field is very useful in heat exchanger analyses and optimizations.In this paper, we analyze some other heat transfer optimization problems in the thermal management s...The uniformity principle of temperature difference field is very useful in heat exchanger analyses and optimizations.In this paper, we analyze some other heat transfer optimization problems in the thermal management system of spacecrafts,including the cooling of thermal components, the one-stream series-wound heat exchanger network, the volume-to-point heat conduction problem, and the radiative heat transfer optimization problem, and have found that the uniformity principle of temperature difference field also holds. When the design objectives under the given constraints are achieved, the distributions of the temperature difference fields are uniform. The principle reflects the characteristic of the distribution of potential in the heat transfer optimization problems. It is also shown that the principle is consistent with the entransy theory. Therefore, although the principle is intuitive and phenomenological, the entransy theory can be the physical basis of the principle.展开更多
The China R/V Xuelong went on the first Arctic scientific cruise, and we obtained 271 hydro-chemical samples from 22 deep-sea stations in the Bering Basin in late July, 1999. Here we describe vertical properties of si...The China R/V Xuelong went on the first Arctic scientific cruise, and we obtained 271 hydro-chemical samples from 22 deep-sea stations in the Bering Basin in late July, 1999. Here we describe vertical properties of silicate [Si] , dissolved inorganic nitrogen [DIN] or [N] (nitrate plus ammonium plus nitrite) , phosphate [P] and oxygen [ O2 ] in seawater under potential temperature-salinity structure. The seasonal stratification in the summer and the water exchanges of the North Pacific Ocean over the Bering Basin resulted in that the four layers of vertical structure with two thermoclines may be found. Vertical [Si] and [N] and [P] profiles show that the nutrients are consumed mainly in ≤50 m and the order of deficient nutrients is [Si] the first, [N] the second and [P] the third. The [N] and [P] increase with depth downward to about 500 m and then both decrease, but the [Si] increases from 150 m to 2000 m or the bottom. In ≥ 150 m the [ O2 ] decreases, which is related with both [P] and [N] increasing closely. Seawater [N] :[P] ratios are 6 - 12 in =≤50 m, 10.5 - 14.3 in 100 - 150 m and 11.7 - 15.8 from 300 m to the bottom.展开更多
It has been challenging to project the tropical cyclone (TC) intensity, structure and destructive potential changes in a warming climate. Here, we compare the sensitivities of TC intensity, size and destructive pote...It has been challenging to project the tropical cyclone (TC) intensity, structure and destructive potential changes in a warming climate. Here, we compare the sensitivities of TC intensity, size and destructive potential to sea surface warming with and without a pre-storm atmospheric adjustment to an idealized state of Radiative-Convective Equilibrium (RCE). Without RCE, we find large responses of TC intensity, size and destructive potential to sea surface temperature (SST) changes, which is in line with some previous studies. However, in an environment under RCE, the TC size is almost insensitive to SST changes, and the sensitivity of intensity is also much reduced to 3% ~C-1-4% ~C-1. Without the pre-storm RCE adjustment, the mean destructive potential measured by the integrated power dissipation increases by about 25% ~C-1 during the mature stage. However, in an environment under RCE, the sensitivity of destructive potential to sea surface warming does not change significantly. Further analyses show that the reduced response of TC intensity and size to sea surface warming under RCE can be explained by the reduced thermodynamic disequilibrium between the air boundary layer and the sea surface due to the RCE adjustment. When conducting regional-scale sea surface warming experiments for TC case studies, without any RCE adjustment the TC response is likely to be unrealistically exaggerated. The TC intensity-temperature sensitivity under RCE is very similar to those found in coupled climate model simulations. This suggests global mean intensity projections under climate change can be understood in terms of a thermodynamic response to temperature with only a minor contribution from any changes in large-scale dynamics.展开更多
The spatial prediction of geothermal sites along the southeast side of Taihang Mountain in the Tangyin rift is a critical goal in the development of renewable energy resources in cities such as Hebi in Henan province,...The spatial prediction of geothermal sites along the southeast side of Taihang Mountain in the Tangyin rift is a critical goal in the development of renewable energy resources in cities such as Hebi in Henan province,which has significant potential for geothermal energy production due to the existence of deep faults and Cenozoic volcano.The study aimed to delineate areas with high geothermal manifestations for detailed geothermal exploration and well-test drilling.To define favorable zones for geothermal potentiality,multi-source datasets were chosen to generate evidence thematic layers that demonstrate the distribution of geothermal anomalies such as geologic maps,structural maps,Land Surface Temperature maps(LST),and hydrothermal mineral alterations maps.The remote sensing and Geographical Information System(GIS)approaches were integrated to map fossil geothermal manifestations and appraise the promising geothermal zones from Landsat 8 OLI/TIRS and Advanced Spaceborne Thermal Emission and Reflection Radiometer-Digital Elevation Model(ASTER-DEM)dataset using the Analytic Hierarchy Process(AHP),which is one of the Mult-criteria Decision Making methods.Results show LST values ranging from 22.6℃ to 45.4℃,with the highest values found along the faults and volcanic areas.The hydrothermal alteration minerals discriminated from band ratios of 4/2,6/5,and 6/7 for iron oxide,ferrous minerals,and clays reveal the presence of high amount of montmorillonite and illite minerals along the faults and volcanoes which are related to hot fluid circulation from subsurface.Structural analysis shows that the major structural trend follows the NNE Tangdong and Tangxi faults,with high density on the west side of the Tangxi fault where there is good exposure of outcrop but less fault density on the east side due to sedimentation in a low land which may conceal geological structures.Lastly,all the thematic layers of geothermal factors were reclassified,ranked,and integrated by the weight overlay logic model based on the influence of geothermal suitability to map potential areas for geothermal resources whereby 5 zones were obtained ranging from very poor to very good.The promising potential sites are mostly found along the highly deep structures of the major Tangxi fault crosscutting the permeable lithology of carbonate rocks and around the Hebi volcanoes.The distribution of hot springs and geothermal wells of the Hebi field were correlated and verified against the potential geothermal anomalies map.The overall integrated method proposes an advanced technique for designing the Tangyin rift’s exploration plan and development actions for geothermal resources utilization,which can be used for exploration of any unveiling geothermal potential sites.展开更多
In order to further understand the characteristics of the floating potential of low earth orbit spacecraft,the effects of the electron current collection area,background electron temperature,photocurrent emission,spac...In order to further understand the characteristics of the floating potential of low earth orbit spacecraft,the effects of the electron current collection area,background electron temperature,photocurrent emission,spacecraft wake,and the shape of spacecraft on spacecraft floating potential were studied here by particle-in-cell simulation in the low earth orbit.The simulation results show that the electron current collection area and background electron temperature impact on the floating potential by changing the electron current collection of spacecraft.By increasing the electron current collection area or background electron temperature,the spacecraft will float at a lower electric potential with respect to the surrounding plasma.However,the spacecraft wake affects the floating potential by increasing the ion current collected by spacecraft.The emission of the photocurrent from the spacecraft surface,which compensates for the electrons collected from background plasma,causes the floating potential to increase.The shape of the spacecraft is also an important factor influencing the floating potential.展开更多
In this paper, we modify the convective vorticity vector (CVV) defined as a cross product of absolute vorticity and gradient of equivalent potential temperature to moist potential vorticity vector (MPVV) defined as a ...In this paper, we modify the convective vorticity vector (CVV) defined as a cross product of absolute vorticity and gradient of equivalent potential temperature to moist potential vorticity vector (MPVV) defined as a cross product of absolute vorticity () and the gradient of the moist-air entropy potential temperature (). The patterns of (MPVV) are compared with the patterns of heavy rainfall events that occurred over different regions in Tanzania on 20<sup>th</sup> to 22<sup>nd</sup> December, 2011 and on 5<sup>th</sup> to 8<sup>th</sup> May, 2015. Moreover, the article aimed at assessing the relative contributions of the magnitude, horizontal and vertical components of (MPVV) detecting on the observed patterns of rainfall events. Dynamic and thermodynamic variables: wind speed, temperature, atmospheric pressure and relative humidity from numerical output generated by the Weather Research and Forecasting (WRF) model running at Tanzania Meteorological Agency (TMA) were used to compute MPVV. It is found that MPVV provide accurate tracking of locations received heavy rainfall, suggesting its potential use as a dynamic tracer for heavy rainfall events in Tanzania. Finally it is found that the first and second components of MPVV contribute almost equally in tracing locations received heavy rainfall events. The magnitude of MPVV described the locations received heavy rainfall events better than the components.展开更多
Thermodynamic concepts required for the thermodynamic calculation of the potentials of electrodes for high temperature applications are briefly reviewed. A thermodynamic approach to the calculation of half cell potent...Thermodynamic concepts required for the thermodynamic calculation of the potentials of electrodes for high temperature applications are briefly reviewed. A thermodynamic approach to the calculation of half cell potentials and the standard chemical potential of an electron at high temperatures which are related to the Standard Hydrogen Electrode(SHE) is discussed. As examples, an external Ag/AgCl reference electrode and a YSZ(Ag|O_2) pH sensor for high temperature applications are analyzed by using the thermodynamic approach to derive a high temperature pH measurement equation. The two electrodes are employed to measure high temperature pH and the measured pH was compared with the calculated pH by using a solution chemistry method. Concepts and principles for electrode kinetics are also briefly introduced and a modification to the Tafel equations is suggested.展开更多
基金jointly supported by the National Key Research and Development Program of China under Grant No. 2017YFC1501601the National Natural Science Foundation of China under Grant Nos. 42175005 and 41875054
文摘In this study,the characteristics of azimuthally asymmetric equivalent potential temperature(θ_(e))distributions in the outer core of tropical cyclones(TCs)encountering weak and strong vertical wind shear are examined using a Lagrangian trajectory method.Evaporatively forced downdrafts in the outer rainbands can transport low-entropy air downward,resulting in the lowestθ_(e)in the downshear-left boundary layer.Quantitative estimations ofθ_(e)recovery indicate that air parcels,especially those originating from the downshear-left outer core,can gradually revive from a low entropy state through surface enthalpy fluxes as the parcels move cyclonically.As a result,the maximumθ_(e)is observed in the downshear-right quadrant of a highly sheared TC.The trajectory analyses also indicate that parcels that move upward in the outer rainbands and those that travel through the inner core due to shear make a dominant contribution to the midlevel enhancement ofθ_(e)in the downshear-left outer core.In particular,the former plays a leading role in suchθ_(e)enhancements,while the latter plays a secondary role.As a result,moist potential stability occurs in the middle-to-lower troposphere in the downshear-left outer core.
基金the National Natural Science Foundation of China(Grant Nos.12164032,11964026,and 12364010)the Natural Science Foundation of Inner Mongolia Autonomous Region,China(Grant Nos.2019MS01010,2022MS01014,and 2020BS01009)+1 种基金the Doctor Research Start-up Fund of Inner Mongolia Minzu University(Grant Nos.BS625 and BS439)the Basic Research Funds for Universities Directly under the Inner Mongolia Autonomous Region,China(Grant No.GXKY23Z029).
文摘We have applied strong coupling unitary transformation method combined with Bose–Einstein statistical law to investigate magnetopolaron energy level temperature effects in halogen ion crystal quantum wells.The obtained results showed that under magnetic field effect,magnetopolaron quasiparticle was formed through the interaction of electrons and surrounding phonons.At the same time,magnetopolaron was influenced by phonon temperature statistical law and important energy level shifts down and binding energy increases.This revealed that lattice temperature and magnetic field could easily affect magnetopolaron and the above results could play key roles in exploring thermoelectric conversion and conductivity of crystal materials.
基金Project supported by the National Natural Science Foundation of China (Grant No.11905076)S&T Program of Hebei (Grant No.SZX2020034)。
文摘A novel emissive probe consisting of an oxide cathode coating is developed to achieve a low operating temperature and long service life.The properties of the novel emissive probe are investigated in detail,in comparison with a traditional tungsten emissive probe,including the operating temperature,the electron emission capability and the plasma potential measurement.Studies of the operating temperature and electron emission capability show that the tungsten emissive probe usually works at a temperature of 1800 K-2200 K while the oxide cathode emissive probe can function at about 1200 K-1400 K.In addition,plasma potential measurements using the oxide cathode emissive probe with different techniques have been accomplished in microwave electron cyclotron resonance plasmas with different discharge powers.It is found that a reliable plasma potential can be obtained using the improved inflection point method and the hot probe with zero emission limit method,while the floating point method is invalid for the oxide cathode emissive probe.
基金The National Key Technologies Research and Development Program of China under contract No.2013BAD13B00the Public Science and Technology Research Funds Project of Ocean under contract No.20155014the Shanghai Universities First-class Disciplines Project(Fisheries)
文摘In the Northwest Pacific Ocean, the squid jigging fisheries from China, Japan and other countries and regions have targeted the west winter-spring cohort of neon flying squid(Ommastrephes bartramii) from August to November since the 1970 s. This squid is a short-lived ecological opportunist with a life-span of about one year,and its population is labile and recruitment variability is driven by the environment or climate change. This variability provides a challenge for ones to forecast the key habitats affected by climate change. The catch data of O. bartramii from Chinese squid jigging fishery and the satellite-derived sea surface temperature(SST) data are used in the Northwest Pacific Ocean from August to November of 1998 to 2004, the SST preferences of O.bartramii corresponding to high values of catch per fishing day(CPUE) are determined and monthly potential habitats are predicted using a histogram analysis of the SST data. The possible changes in the potential habitats of O. bartramii in the Northwest Pacific Ocean are estimated under four climate change scenarios based on the Fourth Assessment Report(AR4) of the Intergovernmental Panel on Climate Change, i.e., 0.5, 1, 2 and 4°C increases in the SST because of the climate change. The results reveal an obvious poleward shift of the potential habitats of O. bartramii in the Northwest Pacific Ocean.
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supported by the National Basic Research Program of China (2009CB421505)the National Natural Science Foundation of China (41075044 and 41075079)
文摘Compared to potential temperature (θ) in the dry atmosphere and equivalent potential temperature (θc) in the saturated atmosphere, generalized potential tem- perature (θ") has already proven a better thermodynamic parameter in describing the non-uniformly saturated real atmosphere. To add otherwise absent graphic explanations, this paper first presents the physical definition of θ through a tephigram. Then, the utility of the measurement in identifying and forecasting the locations of precipita- tion maxima and heat wave areas with diagnostic com- parison studies and traditionally used thermodynamic parameters is shown.
基金supported by the National Natural Science Foundation of China [grant numbers 41730963 and41876020]the SOA Program on Global Change and Air–Sea Interactions [grant number GASI-IPOVAI-03]the Priority Research Program of the Chinese Academy of Sciences [grant number QYZDY-SSW-DQC018]
文摘A regional potential vorticity(PV)intrusion(PVI)(RPVI)index,defined as the sum of the numbers of grids containing PVI within a certain area for each day,is used to reflect the day-to-day PVI variability over northeastern China during winter from 1979 to 2016.The synoptic-scale PVI variations and resultant surface air temperature(SAT)anomalies are identified by comparing the high and low RPVI index cases.In high(low)RPVI cases,significantly strong positive(negative)PV anomalies are found in the stratospheric midlatitudes,which intrude downward mostly within 90°–110°E into the upper troposphere to reach around 300 hPa and extend eastward to the east of 120°E,forcing an anomalous cyclonic(anticyclonic)circulation in the middle and lower troposphere over East Asia,with the anomalous northerlies(southerlies)of the forced lower-tropospheric cyclone(anticyclone)leading to significant negative(positive)SAT anomalies of less(greater)than-0.9°C(0.9°C),especially over northeastern China.In the stratosphere,the positive(negative)midlatitude PV anomalies over northern China are actually associated with a weakening(strengthening)of the polar vortex over the Eurasian continent for the high(low)RPVI cases,resulting mostly from positive(negative)barotropic vorticity anomalies associated with static stability due to the meridional shear of anomalous zonal winds on the southern side of the anomalous Eurasian anticyclone(cyclone).
基金Supported by the China’s National Key Research and Development Projects(No.2016YFA0601803)the National Natural Science Foundation of China(Nos.41490641,41521091,U1606402)the Qingdao National Laboratory for Marine Science and Technology(No.2017ASKJ01)
文摘The energy budgets of the ocean play a crucial role in the analysis of climate change. Potential temperature is traditionally used as a conservative quantity to express variations associated with “heat” in oceanography, such as the heat content and heat transport. However, potential temperature is usually not conserved during turbulent mixing, so the use of conservative temperature is more accurate. Based on climatological simulations under the modern and Last Glacial Maximum (LGM;~21 ka;ka=thousand years ago), as well as a transient climate simulation of the past 22 000 years, we quantify the errors induced by the neglect of the non-conservation of potential temperature in paleo-climate research for the first time. The temperature error reaches 0.9℃ near the coasts aff ected by river discharges but is much smaller in the open oceans, typically 0.03°C above the main thermocline and less than 0.01℃ elsewhere. The error of the ocean heat content (OHC) is roughly 3×10^22 J and is relatively steady over the past 22 000 years. However, the OHC increases to six times the original value during the last glacial termination from 20 ka to 7 ka. As a result, the relative OHC error decreases from 1.2% in the LGM climate to 0.14% in the modern climate. The error of the ocean meridional heat transport (OMHT) is generally smaller than 0.005 PW (1 PW=10 15 W), with very small temporal variations (typically 0.000 4 PW), and induces a relative OMHT error of typically 0.3% over the past 22 000 years. Therefore, the neglect of the non-conservation of potential temperature induces a relative error of generally less than 1% in the analyses of basin-scale climate variations.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11275097,11475085,11105122,and 11535005the Jiangsu Planned Projects for Postdoctoral Research Funds under Grant No 1402006C
文摘Generally speaking, the quark propagator is dependent on the quark chemical potential in the dense quantum chromodynamics (QCD). By means of the generating functional method, we prove that the quark propagator actually depends on p4 + iμ from the first principle of QCD. The relation between quark number density and quark condensate is discussed by analyzing their singularities. It is concluded that the quark number density has some singularities at certain # when T = 0, and the variations of the quark number density as well as the quark condensate are located at the same point. In other words, at a certain # the quark number density turns to nonzero, while the quark condensate begins to decrease from its vacuum value.
基金This work was supported by the National Natural Science Foundation of China(No.51932010)the Sichuan Science and Technology Program(No.2023YFG0042).
文摘Enhancing the piezoelectricity of CaBi_(4)Ti_(4)O_(15)(CBT)ceramics is crucial for improving their application potential in high-temperature piezoelectric devices.Here,we propose a strategy involving the introduction of larger Na/Bi ions at the A-site,effectively inhibiting the tilt of oxygen octahedra and flattening the potential energy profile.This flattening enhances the variation in polarization under external fields.Concurrently,substituting Nb/Mn at the B-site increases the deviation between positive and negative ionic centers,leading to stronger spontaneous polarization,while the induced defect dipoles restrict oxygen vacancy migration and increase the direct current resistivity(ρ_(dc)).The flattened potential energy profile and increased spontaneous polarization significantly enhance the overall performance of cBT ceramics,with the piezoelectric constant(d_(33))reaching 25 pC/N when the Curie temperature(Tc)=752℃.Piezoresponse force microscopy(PFM)and transmission electron microscopy(TEM)revealed submicron-long rectangular domains and nanoscale domains in the modified composition,indicating a high density of domain walls.This study presents an effective approach for enhancing the piezoelectric properties of bismuth layered-structured ferroelectrics(BLSFs),thereby improving the application potential of BLSFsathightemperatures.
基金Supported by the National Natural Science Fund Item (40675071)~~
文摘The key zones of returning farmland to forestland and grassland in Ningxia were studied. By using the "stepwise revised method",the climate productive potential,light and temperature productive potential in the zone in recent 50 years were counted. The light and temperature productive potential of corn in Ningxia irrigated area,the central arid zone and the southern mountain area presented the linear increase trend. But when considered the climate productive potentials of light,temperature and water,the numerical value was very low because of the scarce rainfall,and no agriculture without the irrigation. The light and temperature productive potential,climate productive potential of winter wheat in the central arid zone had no significant trend,but the variation range of climate productive potential was very big. The light and temperature productive potential of winter wheat in the southern mountain area had no significant variation trend,and the climate productive potential presented the weak decline trend. It illustrated that the productive of winter wheat was greatly restricted by the water content. By using the meteorological factor data which were simulated by RegCM3-WOFOST/LINGRA coupled model,the future climate productive potentials of winter wheat in the central south of Ningxia was counted. They both presented the weak increase trend. It illustrated that the climate in Ningxia was favorable to improve the yield of winter wheat after returning farmland to forestland.
文摘A suitable carburized microstructure with fine granular dispersed carbides in hypereutectoid zone,ultra fine martensite in matrix and recrystallized austenite to be refined to the grain size of 12~14 has been obtained by a new process,which is a high carbon concentration carburizing with rare earth element at low temperature(860~880℃)in a discontinuous gas carburization furnace.There was not much difference for the microstructure in eutectic zone between this and conventional process.Forming mechanism of granular carbides has been also studied in this paper.
基金Supporte by the Knowledge Innovation Project of the Chinese Academy of Sciences (No KZCX2-YW-210)National Key Technology Research and Development Program (No2007BAB27B04)the High Technology Research and Development Program of China (No 2001AA635080)
文摘The effects of marine environmental factors-temperature (T), dissolved oxygen (DO), salinity (S) and pH--on the oxidation-reduction potential (ORP) of natural seawater were studied in laboratory. The results show an indistinct relationship between these four factors and the ORE but they did impact the ORP. Common mathematical methods were not applicable for describing the relationship. Therefore, a grey relational analysis (GRA) method was developed. The degrees of correlation were calculated according to GILA and the values of T, pH, DO and S were 0.744, 0.710, 0.692 and 0.690, respectively. From these values, the relations of these factors to the ORP could be described and evaluated, and those of T and pH were relatively major. In general, ORP is influenced by the synergic effect of T, DO, pH and S, with no single factor having an outstanding role.
基金Project supported by the Science Fund for Creative Research Groups of National Natural Science Foundation of China(Grant No.51621062)
文摘The uniformity principle of temperature difference field is very useful in heat exchanger analyses and optimizations.In this paper, we analyze some other heat transfer optimization problems in the thermal management system of spacecrafts,including the cooling of thermal components, the one-stream series-wound heat exchanger network, the volume-to-point heat conduction problem, and the radiative heat transfer optimization problem, and have found that the uniformity principle of temperature difference field also holds. When the design objectives under the given constraints are achieved, the distributions of the temperature difference fields are uniform. The principle reflects the characteristic of the distribution of potential in the heat transfer optimization problems. It is also shown that the principle is consistent with the entransy theory. Therefore, although the principle is intuitive and phenomenological, the entransy theory can be the physical basis of the principle.
基金This work was supported by the 1999 China First Arctic Scientific Investigation,and by the ecological 973 Program of China(G1999043704).
文摘The China R/V Xuelong went on the first Arctic scientific cruise, and we obtained 271 hydro-chemical samples from 22 deep-sea stations in the Bering Basin in late July, 1999. Here we describe vertical properties of silicate [Si] , dissolved inorganic nitrogen [DIN] or [N] (nitrate plus ammonium plus nitrite) , phosphate [P] and oxygen [ O2 ] in seawater under potential temperature-salinity structure. The seasonal stratification in the summer and the water exchanges of the North Pacific Ocean over the Bering Basin resulted in that the four layers of vertical structure with two thermoclines may be found. Vertical [Si] and [N] and [P] profiles show that the nutrients are consumed mainly in ≤50 m and the order of deficient nutrients is [Si] the first, [N] the second and [P] the third. The [N] and [P] increase with depth downward to about 500 m and then both decrease, but the [Si] increases from 150 m to 2000 m or the bottom. In ≥ 150 m the [ O2 ] decreases, which is related with both [P] and [N] increasing closely. Seawater [N] :[P] ratios are 6 - 12 in =≤50 m, 10.5 - 14.3 in 100 - 150 m and 11.7 - 15.8 from 300 m to the bottom.
基金supported by the UK-China Research & Innovation Partnership Fund through the Met Office Climate Science for Service Partnership China as part of the Newton Fundsupported by the National Natural Science Foundation of China(Grant No.41706007)+1 种基金China Postdoctoral Science Foundation(Grant No.2017M611960)the National Programme on Global Change and Air-Sea Interaction(Grant No.GASI-IPOVAI-04)
文摘It has been challenging to project the tropical cyclone (TC) intensity, structure and destructive potential changes in a warming climate. Here, we compare the sensitivities of TC intensity, size and destructive potential to sea surface warming with and without a pre-storm atmospheric adjustment to an idealized state of Radiative-Convective Equilibrium (RCE). Without RCE, we find large responses of TC intensity, size and destructive potential to sea surface temperature (SST) changes, which is in line with some previous studies. However, in an environment under RCE, the TC size is almost insensitive to SST changes, and the sensitivity of intensity is also much reduced to 3% ~C-1-4% ~C-1. Without the pre-storm RCE adjustment, the mean destructive potential measured by the integrated power dissipation increases by about 25% ~C-1 during the mature stage. However, in an environment under RCE, the sensitivity of destructive potential to sea surface warming does not change significantly. Further analyses show that the reduced response of TC intensity and size to sea surface warming under RCE can be explained by the reduced thermodynamic disequilibrium between the air boundary layer and the sea surface due to the RCE adjustment. When conducting regional-scale sea surface warming experiments for TC case studies, without any RCE adjustment the TC response is likely to be unrealistically exaggerated. The TC intensity-temperature sensitivity under RCE is very similar to those found in coupled climate model simulations. This suggests global mean intensity projections under climate change can be understood in terms of a thermodynamic response to temperature with only a minor contribution from any changes in large-scale dynamics.
基金the National Natural Science Foundation of China-Henan Talent Training Joint Foundation,which funded this study(Grant No.U1504404)。
文摘The spatial prediction of geothermal sites along the southeast side of Taihang Mountain in the Tangyin rift is a critical goal in the development of renewable energy resources in cities such as Hebi in Henan province,which has significant potential for geothermal energy production due to the existence of deep faults and Cenozoic volcano.The study aimed to delineate areas with high geothermal manifestations for detailed geothermal exploration and well-test drilling.To define favorable zones for geothermal potentiality,multi-source datasets were chosen to generate evidence thematic layers that demonstrate the distribution of geothermal anomalies such as geologic maps,structural maps,Land Surface Temperature maps(LST),and hydrothermal mineral alterations maps.The remote sensing and Geographical Information System(GIS)approaches were integrated to map fossil geothermal manifestations and appraise the promising geothermal zones from Landsat 8 OLI/TIRS and Advanced Spaceborne Thermal Emission and Reflection Radiometer-Digital Elevation Model(ASTER-DEM)dataset using the Analytic Hierarchy Process(AHP),which is one of the Mult-criteria Decision Making methods.Results show LST values ranging from 22.6℃ to 45.4℃,with the highest values found along the faults and volcanic areas.The hydrothermal alteration minerals discriminated from band ratios of 4/2,6/5,and 6/7 for iron oxide,ferrous minerals,and clays reveal the presence of high amount of montmorillonite and illite minerals along the faults and volcanoes which are related to hot fluid circulation from subsurface.Structural analysis shows that the major structural trend follows the NNE Tangdong and Tangxi faults,with high density on the west side of the Tangxi fault where there is good exposure of outcrop but less fault density on the east side due to sedimentation in a low land which may conceal geological structures.Lastly,all the thematic layers of geothermal factors were reclassified,ranked,and integrated by the weight overlay logic model based on the influence of geothermal suitability to map potential areas for geothermal resources whereby 5 zones were obtained ranging from very poor to very good.The promising potential sites are mostly found along the highly deep structures of the major Tangxi fault crosscutting the permeable lithology of carbonate rocks and around the Hebi volcanoes.The distribution of hot springs and geothermal wells of the Hebi field were correlated and verified against the potential geothermal anomalies map.The overall integrated method proposes an advanced technique for designing the Tangyin rift’s exploration plan and development actions for geothermal resources utilization,which can be used for exploration of any unveiling geothermal potential sites.
基金supported by National Natural Science Foundation of China(No.11105063)
文摘In order to further understand the characteristics of the floating potential of low earth orbit spacecraft,the effects of the electron current collection area,background electron temperature,photocurrent emission,spacecraft wake,and the shape of spacecraft on spacecraft floating potential were studied here by particle-in-cell simulation in the low earth orbit.The simulation results show that the electron current collection area and background electron temperature impact on the floating potential by changing the electron current collection of spacecraft.By increasing the electron current collection area or background electron temperature,the spacecraft will float at a lower electric potential with respect to the surrounding plasma.However,the spacecraft wake affects the floating potential by increasing the ion current collected by spacecraft.The emission of the photocurrent from the spacecraft surface,which compensates for the electrons collected from background plasma,causes the floating potential to increase.The shape of the spacecraft is also an important factor influencing the floating potential.
文摘In this paper, we modify the convective vorticity vector (CVV) defined as a cross product of absolute vorticity and gradient of equivalent potential temperature to moist potential vorticity vector (MPVV) defined as a cross product of absolute vorticity () and the gradient of the moist-air entropy potential temperature (). The patterns of (MPVV) are compared with the patterns of heavy rainfall events that occurred over different regions in Tanzania on 20<sup>th</sup> to 22<sup>nd</sup> December, 2011 and on 5<sup>th</sup> to 8<sup>th</sup> May, 2015. Moreover, the article aimed at assessing the relative contributions of the magnitude, horizontal and vertical components of (MPVV) detecting on the observed patterns of rainfall events. Dynamic and thermodynamic variables: wind speed, temperature, atmospheric pressure and relative humidity from numerical output generated by the Weather Research and Forecasting (WRF) model running at Tanzania Meteorological Agency (TMA) were used to compute MPVV. It is found that MPVV provide accurate tracking of locations received heavy rainfall, suggesting its potential use as a dynamic tracer for heavy rainfall events in Tanzania. Finally it is found that the first and second components of MPVV contribute almost equally in tracing locations received heavy rainfall events. The magnitude of MPVV described the locations received heavy rainfall events better than the components.
文摘Thermodynamic concepts required for the thermodynamic calculation of the potentials of electrodes for high temperature applications are briefly reviewed. A thermodynamic approach to the calculation of half cell potentials and the standard chemical potential of an electron at high temperatures which are related to the Standard Hydrogen Electrode(SHE) is discussed. As examples, an external Ag/AgCl reference electrode and a YSZ(Ag|O_2) pH sensor for high temperature applications are analyzed by using the thermodynamic approach to derive a high temperature pH measurement equation. The two electrodes are employed to measure high temperature pH and the measured pH was compared with the calculated pH by using a solution chemistry method. Concepts and principles for electrode kinetics are also briefly introduced and a modification to the Tafel equations is suggested.