Invasive macroalgae are recognized as one of the greatest threats to local marine ecology and economy.Chaetomorpha valida is an invasive species in China,originally found in Dalian City,Liaoning Province,and has now i...Invasive macroalgae are recognized as one of the greatest threats to local marine ecology and economy.Chaetomorpha valida is an invasive species in China,originally found in Dalian City,Liaoning Province,and has now invaded southward to seas such as Rongcheng City,Shandong Province.Its overgrowth has seriously damaged the local mariculture industry.Based on two strains of C.valida isolated in our previous study,this study explores the effects of temperature and irradiance on their growth and reproduction under laboratory conditions.The results show that the suitable temperature ranges are primarily 21−29℃.The optimal temperature is 25℃for gametophytic growth and sporophytic asexual reproduction,and 29℃for sporophytic growth and gametophytic sexual reproduction.And there is no significant effect of irradiance on their growth and reproduction.Meanwhile,the suitable temperature ranges and optimum irradiance for the growth and reproduction of both strains are largely similar,with only slight differences in the suitable ones for sporophytic asexual reproduction and gametophytic growth.Accordingly,the effect of temperature on the isomorphic generation alternation in C.valida was analyzed,as well as the dynamics of its generation alternation and invasive potential for its environmental adaptation in the northern and southern seas of China.This will help to understand its dynamic pattern spreading from the north to south in China,and also be an important reference for understanding the generation alternation characteristics,invasions and prevention of the outbreaks of other green tidal algae.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
For Ti-doped hematite photoanodes, high temperature annealing drastically increases the water oxidation plateau photocurrent, but also induces an anodic shift of onset potential by about 100 m V, thus hindering the pe...For Ti-doped hematite photoanodes, high temperature annealing drastically increases the water oxidation plateau photocurrent, but also induces an anodic shift of onset potential by about 100 m V, thus hindering the performance under low applied bias. To the best of our knowledge, the effects of high temperature annealing on the onset potential have been rarely studied. Herein, both X-ray photoelectron spectroscopy（XPS） measurements and theoretical calculations indicated that the increase of surface Ti/Fe atomic ratio after high temperature annealing decreased the adsorption capacity of hydroxide ions on the hematite surface. Subsequently, the flatband potential（i.e., the theoretical onset potential） of Ti doped hematite photoanodes positively shifted, which was supported by the Mott-Schottky measurements.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
By a combination method of Lee-Low-Pines unitary transformation method and Pekar-type variational method,the ground state energy(GSE)of the bound polaron is studied in the asymmetrical Gaussian potential quantum well ...By a combination method of Lee-Low-Pines unitary transformation method and Pekar-type variational method,the ground state energy(GSE)of the bound polaron is studied in the asymmetrical Gaussian potential quantum well considering the temperature and electromagneticfield.The impacts of the temperature and asymmetrical Gaussian potential,electromagnetic field and phonon-electron coupling upon the GSE are obtained.The results show that the GSE of the bound polaron not only oscillates as the temperature changes regardless of the electromagneticfield and asymmetrical Gaussian potential and Coulomb impurity potential(CIP)and electron-phonon coupling but also has different rules with the electromagnetic field and asymmetrical Gaussian potential and CIP and electron-phonon coupling at different temperature zones.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
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
Dealing with both elemental and high-Tc superconductors (SCs) - Sn, Nb and Pb belonging to the former category, and MgB2 and different samples of YBCO to the latter - we show that the difference in the values of their...Dealing with both elemental and high-Tc superconductors (SCs) - Sn, Nb and Pb belonging to the former category, and MgB2 and different samples of YBCO to the latter - we show that the difference in the values of their critical magnetic field Hc1,c2 and the penetration depth λL(0) is, remarkably, attributable predominantly to the difference in the values of a single parameter, viz., the chemical potential (μ) close to their critical temperatures (Tcs). Based directly on the dynamics of pairing in a magnetic field and the corresponding number equation, our approach relates Hc1,c2 of an SC with the following set of its properties: S1 = {μ, Tc, Debye temperature, effective mass of the electron, magnetic interaction parameter, Landau index}. Hence, it provides an alternative to the approach followed by Talantsev [Mod. Phys. Lett. B 33, 1950195 (2019)] who has shown by ingeniously combining the results of various well-established theories that Hc2 of an SC can be calculated via four different equations, each of which invokes two or more properties from its sample-specific set S2 = {Tc, gap, coherence length, λL(0), jump in sp. ht.}, which is radically different from S1.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
Geothermal energy is a renewable and environmentally sustainable resource of increasing importance.However,areas with geothermal potential are not easily detected by traditional field investigations,requiring the deve...Geothermal energy is a renewable and environmentally sustainable resource of increasing importance.However,areas with geothermal potential are not easily detected by traditional field investigations,requiring the development of new,robust,and reliable models for detection.In this study,remote sensing data and ground-based variables were used to detect and analyze geothermal resource potential areas.General Land Surface Temperature(GLST)was integrated using 5 years of remote sensing data.Landsat 8 daytime GLST(Landsat-GLST),Moderate Resolution Imaging Spectroradiometer(MODIS)daytime GLST(MODIS-DLST),and MODIS nighttime GLST(MODIS-NLST)data were integrated with Landsat Nighttime Land Surface Temperature(Night-LST),which not only filled the gap of Landsat Night-LST but also improved the spatial resolution of MODIS nighttime temperatures.Specifically,three independent variables(Night-LST,Distance From Known Geothermal Resource Points[DFGP],and Distance From Geological Faults[DFF])were used to develop a weighted model to form a Geothermal Detection Index(GDI)based on Principal Component Analysis(PCA).Along with field verification,the GDI was successfully used to identify three geothermal activity areas in Tengchong City,Yunnan Province.Overall,this work provides a novel method for detecting geothermal potential to support the successful exploitation of geothermal resources.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
According to the meteorological observation data of 72 stations from 1960 to 2010 in the Huanghe （Yellow） River Watershed, China, the long-term variations of potential evapotranspiration, calculated in the modified ...According to the meteorological observation data of 72 stations from 1960 to 2010 in the Huanghe （Yellow） River Watershed, China, the long-term variations of potential evapotranspiration, calculated in the modified Penman-Monteith model of Food and Agricul- ture Organization of the United Nations, were presented, as well as the meteorological causes for the decrease of potential evapotranspiration were discussed. Since 1960, temperature has risen significantly and potential evapotranspiration a decreasing trend, which indicated the existence of ＂Evaporation paradox＂ in the Huanghe River Watershed. This phenomenon was not consistent spatially or temporally with the increase of temperature, potential evapotranspiration decreased in spring, summer and winter, mainly over most parts of Shanxi and Henan, and some parts of Gansu, Ningxia, Inner Mongolia, and Shaanxi. During the recent half century, the trends of temperature and potential evapotranspiration were negatively correlated at most of the stations, while precipitation and potential evapotranspiration exhibited a contrary trend. Calculated in multiple regressions, the contribution to potential evapotranspiration change of related meteorological factors was discussed, including mean pressure, maximum and minimum temperature, sunshine hours, relative humidity and average wind speed. The decrease of wind speed in the Huanghe River Watershed may be the dominating factor causing potential evapotranspiration decreasing.展开更多
The multi-piped freezing method is usually applied in artificial ground freezing （AGF） projects to fulfill special construction requirements, such as two-, three-, or four-piped freezing. Based on potential superpos...The multi-piped freezing method is usually applied in artificial ground freezing （AGF） projects to fulfill special construction requirements, such as two-, three-, or four-piped freezing. Based on potential superposition theory, this paper gives analytical solutions to steady-state frozen temperature for two, three, and four freezing pipes with different temperatures and arranged at random. Specific solutions are derived for some particular arrangements, such as three freezing pipes in a linear arrangement with equal or unequal spacing, right and isosceles triangle arrangements, four freezing pipes in a linear arrangement with equal spacing, and rhombus and rectangle arrangements. A comparison between the analytical solutions and numerical thermal analysis shows that the analytical solutions are sufficiently precise. As a part of the theory of AGF, the analytical solutions of temperature fields for multi-piped freezing with arbitrary layouts and different temperatures of freezing pipes are approached for the first time.展开更多
The existing analytical formulas to calculate the temperature field distribution of artificial frozen soil walls are all based on the conditions that the surface temperatures of all freezing pipes are equivalent. In t...The existing analytical formulas to calculate the temperature field distribution of artificial frozen soil walls are all based on the conditions that the surface temperatures of all freezing pipes are equivalent. In this paper, analytical solution of steady state temperature field of two freezing pipes with diferent temperatures is deduced based on thermal potential superposition method. The correctness of the analytical formulas is verified by comparing the temperature field distributions of the analytical formulas and those of the numerical simulations in the same conditions. And discussions are made to analyze the influence of some parameters on temperature field distribution of this condition.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
基金The National Natural Science Foundation of China under contract Nos 32270219 and 31970216.
文摘Invasive macroalgae are recognized as one of the greatest threats to local marine ecology and economy.Chaetomorpha valida is an invasive species in China,originally found in Dalian City,Liaoning Province,and has now invaded southward to seas such as Rongcheng City,Shandong Province.Its overgrowth has seriously damaged the local mariculture industry.Based on two strains of C.valida isolated in our previous study,this study explores the effects of temperature and irradiance on their growth and reproduction under laboratory conditions.The results show that the suitable temperature ranges are primarily 21−29℃.The optimal temperature is 25℃for gametophytic growth and sporophytic asexual reproduction,and 29℃for sporophytic growth and gametophytic sexual reproduction.And there is no significant effect of irradiance on their growth and reproduction.Meanwhile,the suitable temperature ranges and optimum irradiance for the growth and reproduction of both strains are largely similar,with only slight differences in the suitable ones for sporophytic asexual reproduction and gametophytic growth.Accordingly,the effect of temperature on the isomorphic generation alternation in C.valida was analyzed,as well as the dynamics of its generation alternation and invasive potential for its environmental adaptation in the northern and southern seas of China.This will help to understand its dynamic pattern spreading from the north to south in China,and also be an important reference for understanding the generation alternation characteristics,invasions and prevention of the outbreaks of other green tidal algae.
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 the National Natural Science Foundation of China (Nos. 21473090, U1663228)
文摘For Ti-doped hematite photoanodes, high temperature annealing drastically increases the water oxidation plateau photocurrent, but also induces an anodic shift of onset potential by about 100 m V, thus hindering the performance under low applied bias. To the best of our knowledge, the effects of high temperature annealing on the onset potential have been rarely studied. Herein, both X-ray photoelectron spectroscopy（XPS） measurements and theoretical calculations indicated that the increase of surface Ti/Fe atomic ratio after high temperature annealing decreased the adsorption capacity of hydroxide ions on the hematite surface. Subsequently, the flatband potential（i.e., the theoretical onset potential） of Ti doped hematite photoanodes positively shifted, which was supported by the Mott-Schottky measurements.
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 National Natural Science Foundation of China under Grant No.11975011。
文摘By a combination method of Lee-Low-Pines unitary transformation method and Pekar-type variational method,the ground state energy(GSE)of the bound polaron is studied in the asymmetrical Gaussian potential quantum well considering the temperature and electromagneticfield.The impacts of the temperature and asymmetrical Gaussian potential,electromagnetic field and phonon-electron coupling upon the GSE are obtained.The results show that the GSE of the bound polaron not only oscillates as the temperature changes regardless of the electromagneticfield and asymmetrical Gaussian potential and Coulomb impurity potential(CIP)and electron-phonon coupling but also has different rules with the electromagnetic field and asymmetrical Gaussian potential and CIP and electron-phonon coupling at different temperature zones.
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.
文摘Dealing with both elemental and high-Tc superconductors (SCs) - Sn, Nb and Pb belonging to the former category, and MgB2 and different samples of YBCO to the latter - we show that the difference in the values of their critical magnetic field Hc1,c2 and the penetration depth λL(0) is, remarkably, attributable predominantly to the difference in the values of a single parameter, viz., the chemical potential (μ) close to their critical temperatures (Tcs). Based directly on the dynamics of pairing in a magnetic field and the corresponding number equation, our approach relates Hc1,c2 of an SC with the following set of its properties: S1 = {μ, Tc, Debye temperature, effective mass of the electron, magnetic interaction parameter, Landau index}. Hence, it provides an alternative to the approach followed by Talantsev [Mod. Phys. Lett. B 33, 1950195 (2019)] who has shown by ingeniously combining the results of various well-established theories that Hc2 of an SC can be calculated via four different equations, each of which invokes two or more properties from its sample-specific set S2 = {Tc, gap, coherence length, λL(0), jump in sp. ht.}, which is radically different from S1.
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supported by the National Natural Science Foundation of China[Grant No.41961064]Yunnan Fundamental Research Projects[Grant No.202001BB050030]+2 种基金the Plateau Mountain Ecology and Earth’s Environment Discipline Construction Project[Grant No.C1762101030017]Joint Foundation Project between Yunnan Science and Technology Department and Yunnan University[Grant No.C176240210019]Joint Foundation Project between Yunnan Science and Technology Department and Yunnan University[Grant No.2018FY-019].
文摘Geothermal energy is a renewable and environmentally sustainable resource of increasing importance.However,areas with geothermal potential are not easily detected by traditional field investigations,requiring the development of new,robust,and reliable models for detection.In this study,remote sensing data and ground-based variables were used to detect and analyze geothermal resource potential areas.General Land Surface Temperature(GLST)was integrated using 5 years of remote sensing data.Landsat 8 daytime GLST(Landsat-GLST),Moderate Resolution Imaging Spectroradiometer(MODIS)daytime GLST(MODIS-DLST),and MODIS nighttime GLST(MODIS-NLST)data were integrated with Landsat Nighttime Land Surface Temperature(Night-LST),which not only filled the gap of Landsat Night-LST but also improved the spatial resolution of MODIS nighttime temperatures.Specifically,three independent variables(Night-LST,Distance From Known Geothermal Resource Points[DFGP],and Distance From Geological Faults[DFF])were used to develop a weighted model to form a Geothermal Detection Index(GDI)based on Principal Component Analysis(PCA).Along with field verification,the GDI was successfully used to identify three geothermal activity areas in Tengchong City,Yunnan Province.Overall,this work provides a novel method for detecting geothermal potential to support the successful exploitation of geothermal resources.
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National Natural Science Foundation of China, No.41161012Program for New Century Excellent Talents in University by the Ministry of Education of China, No.NCET-10-0019Basic Scientific Research Foundation in University of Gansu Province
文摘According to the meteorological observation data of 72 stations from 1960 to 2010 in the Huanghe （Yellow） River Watershed, China, the long-term variations of potential evapotranspiration, calculated in the modified Penman-Monteith model of Food and Agricul- ture Organization of the United Nations, were presented, as well as the meteorological causes for the decrease of potential evapotranspiration were discussed. Since 1960, temperature has risen significantly and potential evapotranspiration a decreasing trend, which indicated the existence of ＂Evaporation paradox＂ in the Huanghe River Watershed. This phenomenon was not consistent spatially or temporally with the increase of temperature, potential evapotranspiration decreased in spring, summer and winter, mainly over most parts of Shanxi and Henan, and some parts of Gansu, Ningxia, Inner Mongolia, and Shaanxi. During the recent half century, the trends of temperature and potential evapotranspiration were negatively correlated at most of the stations, while precipitation and potential evapotranspiration exhibited a contrary trend. Calculated in multiple regressions, the contribution to potential evapotranspiration change of related meteorological factors was discussed, including mean pressure, maximum and minimum temperature, sunshine hours, relative humidity and average wind speed. The decrease of wind speed in the Huanghe River Watershed may be the dominating factor causing potential evapotranspiration decreasing.
基金Project supported by the National Natural Science Foundation of China （Nos. 51178336 and 51478340）, the Natural Science Foundation of Zhejiang Province, China （No. LZ13E080002）, and the China Ministry of Communications Construction Science ＆ Technology Projects （No. 2013318R11300）
文摘The multi-piped freezing method is usually applied in artificial ground freezing （AGF） projects to fulfill special construction requirements, such as two-, three-, or four-piped freezing. Based on potential superposition theory, this paper gives analytical solutions to steady-state frozen temperature for two, three, and four freezing pipes with different temperatures and arranged at random. Specific solutions are derived for some particular arrangements, such as three freezing pipes in a linear arrangement with equal or unequal spacing, right and isosceles triangle arrangements, four freezing pipes in a linear arrangement with equal spacing, and rhombus and rectangle arrangements. A comparison between the analytical solutions and numerical thermal analysis shows that the analytical solutions are sufficiently precise. As a part of the theory of AGF, the analytical solutions of temperature fields for multi-piped freezing with arbitrary layouts and different temperatures of freezing pipes are approached for the first time.
基金the National Natural Science Foundation of China(Nos.50578120 and 51178336)the Science and Technology Project of the Zhejiang Department of Transportation(No.2010H02)
文摘The existing analytical formulas to calculate the temperature field distribution of artificial frozen soil walls are all based on the conditions that the surface temperatures of all freezing pipes are equivalent. In this paper, analytical solution of steady state temperature field of two freezing pipes with diferent temperatures is deduced based on thermal potential superposition method. The correctness of the analytical formulas is verified by comparing the temperature field distributions of the analytical formulas and those of the numerical simulations in the same conditions. And discussions are made to analyze the influence of some parameters on temperature field distribution of this condition.
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.
