Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor devices.PS fiber-like structures have wide applications ...Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor devices.PS fiber-like structures have wide applications in multi-functional semiconductor devices.In this paper,a one-dimensional(1D)theoretical model is established to describe the piezotronic responses of a PS fiber under gradient temperature changes.The theoretical model aims to explain the mechanism behind the resistance change caused by such gradient temperature changes.Numerical results demonstrate that a gradient temperature change significantly affects the physical fields within the PS fiber,and can induce changes in its surface resistance.It provides important theoretical guidance on the development of piezotronic devices that are sensitive to temperature effects.展开更多
New estimations of radiative forcing due to CO2 were calculated using updated concentration data of CO2 and a high-resolution radiative transfer model. The stratospheric adjusted radiative forcing (ARF) due to CO2 f...New estimations of radiative forcing due to CO2 were calculated using updated concentration data of CO2 and a high-resolution radiative transfer model. The stratospheric adjusted radiative forcing (ARF) due to CO2 from the year 1750 to the updated year of 2010 was found to have increased to 1.95 W m-2, which was 17% larger than that of the IPCC's 4th Assessment Report because of the rapid increase in CO2 concentrations since 2005. A new formula is proposed to accurately describe the relationship between the ARF of CO2 and its concentration. Furthermore, according to the relationship between the ARF and surface temperature change, possible changes in equilibrium surface temperature were estimated under the scenarios that the concentration of CO2 increases to 1.5, 2, 2.5, 3, 3.5 and 4 times that of the concentration in the year 2008. The result was values of +2.2℃, +3.8℃, +5.1℃, +6.2℃, +7.1℃ and +8.0℃ respectively, based on a middle-level climate sensitivity parameter of 0.8 K (W m 3)-1. Non-equilibrium surface temperature changes over the next 500 years were also calculated under two kinds of emission scenarios (pulsed and sustained emissions) as a comparison, according to the Absolute Global Temperature change Potential (AGTP) of CO2. Results showed that CO2 will likely continue to contribute to global warming if no emission controls are imposed, and the effect on the Earth-atmosphere system will be difficult to restore to its original level.展开更多
Using a detailed, fully coupled chemistry climate model (CCM), the effect of increasing stratospheric H20 on ozone and temperature is investigated. Different CCM time-slice runs have been performed to investigate th...Using a detailed, fully coupled chemistry climate model (CCM), the effect of increasing stratospheric H20 on ozone and temperature is investigated. Different CCM time-slice runs have been performed to investigate the chemical and radiative impacts of an assumed 2 ppmv increase in H20. The chemical effects of this H20 increase lead to an overall decrease of the total column ozone (TCO) by ~1% in the tropics and by a maximum of 12% at southern high latitudes. At northern high latitudes, the TCO is increased by only up to 5% due to stronger transport in the Arctic. A 2-ppmv H2O increase in the model's radiation scheme causes a cooling of the tropical stratosphere of no more than 2 K, but a cooling of more than 4 K at high latitudes. Consequently, the TCO is increased by about 2%-6%. Increasing stratospheric H2O, therefore, cools the stratosphere both directly and indirectly, except in the polar regions where the temperature responds differently due to feedbacks between ozone and H2O changes. The combined chemical and radiative effects of increasing H2O may give rise to more cooling in the tropics and middle latitudes but less cooling in the polar stratosphere. The combined effects of H2O increases on ozone tend to offset each other, except in the Arctic stratosphere where both the radiative and chemical impacts give rise to increased ozone. The chemical and radiative effects of increasing H2O cause dynamical responses in the stratosphere with an evident hemispheric asymmetry. In terms of ozone recovery, increasing the stratospheric H2O is likely to accelerate the recovery in the northern high latitudes and delay it in the southern high latitudes. The modeled ozone recovery is more significant between 2000 ~2050 than between 2050~2100, driven mainly by the larger relative change in chlorine in the earlier period.展开更多
This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation ...This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation in China has exhibited significant 50–70-yr, 100–120-yr, and 200–250-yr cycles. Results also show that the amplitudes of decadal and centennial temperature variation were 1.3℃ and 0.7℃, respectively, with the latter significantly correlated with long-term changes in solar radiation, especially cold periods, which correspond approximately to sunspot minima. The most rapid warming in China occurred over AD 1870–2000, at a rate of 0.56°± 0.42℃(100 yr)^(-1); however, temperatures recorded in the 20 th century may not be unprecedented for the last 2000 years, as data show records for the periods AD 981–1100 and AD1201–70 are comparable to the present. The ensemble means of dryness/wetness spatial patterns in eastern China across all centennial warm periods illustrate a tripole pattern: dry south of 25°N, wet from 25°–30°N, and dry to the north of 30°N. However, for all centennial cold periods, this spatial pattern also exhibits a meridional distribution. The increase in precipitation over the monsoonal regions of China associated with the 20 th century warming can primarily be attributed to a mega El Nino–Southern Oscillation and the Atlantic Multidecadal Oscillation. In addition, a significant association between increasing numbers of locusts and dry/cold conditions is found in eastern China. Plague intensity also generally increases in concert with wetness in northern China, while more precipitation is likely to have a negative effect in southern China.展开更多
A series of alloys (Gd1-xHox)5Si4(x=0, 0.05, 0.15, 0.25) have been prepared. Adiabatic temperature changes of(Gd1-xHox)5Si4 alloys is exactly investigated by a control and analysis system for ΔH=1.4 T, and the measur...A series of alloys (Gd1-xHox)5Si4(x=0, 0.05, 0.15, 0.25) have been prepared. Adiabatic temperature changes of(Gd1-xHox)5Si4 alloys is exactly investigated by a control and analysis system for ΔH=1.4 T, and the measurement results are trustworthy. Curie temperatures of these alloys are tunable in a wide temperature region, and decrease almost linearly with the increasing of Ho content. Magnetic entropy changes in the (Gd1-xHox)Si4 compounds are about 2.35 J/(kg·K) when magnetic field change are 0~1.4 T. The adiabatic temperatures of these alloys at Curie Points are larger than 1 K about 40% of that of Gd in a field change 0~1.4 T, and the curves of ΔTad are as wide as that of Gd. The relative cooling power RCP(S) or RCP(T) of these alloys are about 0.5~0.7 J·cm-3 and 42~50 K2 on the field 0~1.4 T, about 58% and 55% of that of Gd respectively. These alloys are potential magnetic refrigerants working in a refrigerator at room temperatures.展开更多
Solvent-free nanofluids hold promise for many technologically significant applications.The liquid-like behavior,a typical rheological property of solvent-free nanofluids,has aroused considerable interests.However,ther...Solvent-free nanofluids hold promise for many technologically significant applications.The liquid-like behavior,a typical rheological property of solvent-free nanofluids,has aroused considerable interests.However,there has been still lack of efficient methods to predict and control the liquid-like behavior of solvent-free nanofluids.In this paper,we propose a semi-discrete dynamic system with stochastic excitation describing the temperature change effects on the rheological property of multiwall carbon nanotubes(MWCNTs)modified by grafting sulfonic acid terminated organosilanes as corona and tertiary amine as canopy,which is a typical covalent-type solvent-free nanofluid system.The vibration of the grafting branches is simulated by employing a structure-preserving approach,and the shear force of grafting branches at the fixed end is computed subsequently.By taking the shear forces as an excitation acting on the MWCNTs,the axial motion of the MWCNTs is solved with the 7-point Gauss-Kronrod quadrature rule.The critical temperature associated with the appearance of the liquid-like behavior as well as the upper bound of the moving speed of the modified MWCNTs is determined,which can be used to predict and control the liquid-like behavior of the modified MWCNTs in engineering applications.展开更多
Abstract: In 1876 Blytt proposed a post-glacial climatic classification, maintaining that the then temperature fluctuated 1–2°C higher or lower than that today. Lamb (1969) held that in Europe “the axis of the ...Abstract: In 1876 Blytt proposed a post-glacial climatic classification, maintaining that the then temperature fluctuated 1–2°C higher or lower than that today. Lamb (1969) held that in Europe “the axis of the subtropical high pressure belt was generally displaced north by about 10° latitudes” during the Hypsithermal and that the temperature was three to six times higher than that in the postglacial period.展开更多
[Objective] The study aimed to discuss the effects of coal mining subsided water area on temperature change in Huaibei coal mine. [Method] Based on the data of monthly temperature from 1957 to 2007 recorded by Suixi ...[Objective] The study aimed to discuss the effects of coal mining subsided water area on temperature change in Huaibei coal mine. [Method] Based on the data of monthly temperature from 1957 to 2007 recorded by Suixi (coal mining subsided water area) and Fuyang stations (control), the effects of coal mining subsided water area on temperature change in Huaibei coal mine were discussed using linear trend estimation and comparative analysis methods. [Result] Spring, autumn, winter and annual average temperatures of coal mining subsided water area (Suixi) were increased in the last 51 years, and the increase of winter temperature was mostly significant with a tendency rate of 0.49 ℃/10 a. Meanwhile, annual temperature range of coal mining subsided water area was decreased from 1957 to 2007. Temperatures of Suixi in four seasons were lower than those of Fuyang from the 1960s to 1990s, and temperatures of coal mining subsided water area (Suixi) were higher than those of Fuyang in spring, autumn and winter but lower than those of Fuyang in summer from 2000 to 2007. [ Result] Coal mining subsided water area had certain effects on temperature change of Huaibei coal mine.展开更多
The spatial and temporal variation characteristics of temperature were analyzed by using climate tendency coefficient, climatic inclination rate and Mann-Kendall catastrophe test,based on the annual and seasonal avera...The spatial and temporal variation characteristics of temperature were analyzed by using climate tendency coefficient, climatic inclination rate and Mann-Kendall catastrophe test,based on the annual and seasonal average temperatures of 28 meteorological stations in Guangxi from 1971 to 2013. Under the global warming,the annual and seasonal average temperatures in typical karst area of Guangxi had an increasing trend. The cli- mate inclination rate of annual average temperature reached a significant level, which was about 0.17 ℃/10 a, and the year of abrupt changes ap- peared in 1996. About seasonal temperature's trend, average temperatures of all the four seasons had an increase trend in the past 43 years, and the significant increase was happened in autumn with the temperature increase rate of 0.28 ℃/10 a, followed by increase rate of average tempera- ture in winter with 0.25 ℃/10 a. A long-term warming tendency was observed by seasonal average temperature from 1971 to 2013, especially dur- ing 2002 - 2013.展开更多
Respiratory disease and cardio-cerebral vascular disease frequently occur in Anyang City. In this paper, by comparing incidence num- bers of respiratory disease and cardio-cerebral vascular disease in Anyang People's...Respiratory disease and cardio-cerebral vascular disease frequently occur in Anyang City. In this paper, by comparing incidence num- bers of respiratory disease and cardio-cerebral vascular disease in Anyang People's Hospital during 2010 -2012 with seasonal change of local tem- perature,it is found that they have obvious relationship, which has very important significance for preventing respiratory disease and cardio-cerebral vascular disease in the future.展开更多
[Objective] The aim was to study air temperature changes and urbanization contribution ration in Kunming City in recent 50 years. [ Method] The observation data of air temperature series from Kunming station and other...[Objective] The aim was to study air temperature changes and urbanization contribution ration in Kunming City in recent 50 years. [ Method] The observation data of air temperature series from Kunming station and other four surrounding meteorological stations were used to in- vestigate air temperature variation in Kunming station affected by urbanization during 1960 -2009. [ Result] The trend slope of mean annual temper- ature was 0.402 ~(3/10 a in Kunming station and 0. 103 ~C/10 a in other four surrounding meteorological stations, and the increasing magnitude of air temperature in Kunming station was more than 3 times that of average global warming in the past 50 year. The effect of urbanization on mean an- nual temperature in Kunming station started from 1990. During 1990 -1994, the increasing contribution rate of urbanization to air temperature in Kunming station was less than 40%. From 1995 to 2009, the contribution ratio was more than 50%, up to about 60% in all seasons. Urban heat is- land effect in Kunming station was intensified with the development of urbanization. In addition, the warming rate caused by urban heat island effect in Kunming station was the greatest in dry season, followed by mean annual temperature, and it was the weakest in rainy season. [ Conclusion] The study provided theoretical foundation for future research.展开更多
The short-term temperature fluctuation caused by global climate change is one of the risk factors affecting public health.Exploring the association between temperature fluctuation and diseases,which has received relat...The short-term temperature fluctuation caused by global climate change is one of the risk factors affecting public health.Exploring the association between temperature fluctuation and diseases,which has received relatively limited research attention,can contribute to enhancing awareness of health risks and taking timely measures for health risk alert and management.Therefore,this study aims to investigate the relationship between temperature change between neighboring days(TCN)and hospitalizations,identify diseases sensitive to extreme TCN,and evaluate the related disease burden.We collected meteorological and hospitalization data from 2014 to 2019 in 23 sites of China to explore the impact of TCN on hospitalizations.We first quantified site-specific associations between TCN and hospitalizations and then conducted meta-analysis to pool the results,to assess the relative risk of extreme TCN for susceptible diseases,and to estimate the related disease burden attributed to TCN.Stratified analyses were undertaken by age,sex,and disease type.Results showed that all-cause hospital admission was significantly linked to TCN.A negative TCN(below-1.9℃)in the cool season and a positive TCN(above 1.0℃)in the warm season increased the risk of hospitalization.People aged 15-64 years,men,and patients with musculoskeletal system or connective tissue diseases were more sensitive to extremely negative TCN during the cool season.People aged over 65 years,men,and patients with respiratory diseases were more sensitive to extremely positive TCN during the warm season.The attributable fraction to all-cause hospitalization from negative TCN in the cool season was 2.05%(95%CI:-0.90%,4.53%)and from positive TCN in the warm season was 5.79%(95%CI:2.98%,8.31%).Circulatory diseases in the cool season and respiratory diseases in the warm season had the highest disease burden.Our findings indicate that awareness of TCN and its health risks should be promoted and evidence-informed policies are needed to reduce the risk of TCN.展开更多
The discovery of biological activities of natural products plays a vital part in drug development.The mechanism by which organisms respond to temperature changes via biosynthesis of natural products remained largely c...The discovery of biological activities of natural products plays a vital part in drug development.The mechanism by which organisms respond to temperature changes via biosynthesis of natural products remained largely cryptic.A thermophilic fungus under cold stress turned black and accumulated a polyketide metabolite 1 and lipid mass.Deficiency in 1 caused melanin loss and accumulated extra lipid mass,unexpectedly leading to seriously damaged mitochondria diagnostic for ferroptosis.Further analysis revealed that lipid mass induced by cold stress intensively increased ferroptosis risk and 1 functioned as cell wall reinforcer against mass lipid accumulation and as reactive oxygen species scavenger against lipid peroxidation.We also found that melanin in mice lowered lipid level but enhanced animal resistance to cold stress.Treatment with melanin precursors significantly increased mouse cell survival rate under cold stress.Our results unveiled a metabolite-lipid-ferroptosis-cold relationship,which provided mechanistic insights into the functions of most common metabolites and into diseases related to cold stress.These findings opened a perspective for developing anti-cold and anti-ferroptosis therapeutics and agents.展开更多
Studying the abrupt change of winter temperature(ACWT)over the Mongolian Plateau(MP,including Inner Mongolia Autonomous Region and State of Mongolia)is of great significance for understanding the spatiotemporal distri...Studying the abrupt change of winter temperature(ACWT)over the Mongolian Plateau(MP,including Inner Mongolia Autonomous Region and State of Mongolia)is of great significance for understanding the spatiotemporal distribution of temperature and the mechanism of global climate change.Monthly temperature data during 1961–2017was collected,and the abrupt change point was determined by the Mann–Kendall test and sliding ttest,to analyze the characteristics and causes of ACWT.The results showed that(a)The winter temperature has rapidly increased with a trend of 0.41℃/10a,which was significantly higher than that of the rest area of Chinese mainland,indicating that climate change in the MP was more sensitive to global warming.(b)The abrupt change point occurred in 1988,with temperature of-15.5℃and-14.1℃before and after abrupt change,respectively.The ACWT in 50°N was 1–3 years later than that in 40°N,and the isotherms of different temperatures moved northward by 10–200 km,especially-16℃isotherms moved approximately 200 km northward after 1988.(c)The Arctic Oscillation(AO)and Mongolian High(MH)anomaly affects winter temperature over the MP.When the AO is unusually strong,the MH and East Asian winter monsoon are weak,and southerly winds prevail in most regions,which is not conducive to the cold air developing southward,leading to higher winter temperature in the MP.Overwise,abnormally northerly winds prevail and temperature is low.Meanwhile,the abrupt change time of AO occurred in 1987 before winter temperature.It shows that the AO indirectly causes winter temperatures to rise by influencing the MH and is also the main driving factor of ACWT.展开更多
Using radiosonde and satellite observations, we investigated the trends of air temperature changes over the Tibetan Plateau (TP) in comparison with those over other regions in the same latitudes from 1979 to 2002. I...Using radiosonde and satellite observations, we investigated the trends of air temperature changes over the Tibetan Plateau (TP) in comparison with those over other regions in the same latitudes from 1979 to 2002. It is shown that Over the TP, the trends of air temperature changes in the upper troposphere to lower stratosphere were out of phase with those in the lower to middle troposphere. Air temperature decreased and a decreasing trend appeared in the upper troposphere to lower stratosphere. The amplitude of the annual or seasonal mean temperature decreases over the TP was larger than that over the whole globe. In the lower to middle troposphere over the TP, temperature increased, and the increasing trend was stronger than that over the non-plateau regions in the same latitudes in the eastern part of China. Meanwhile, an analysis of the satellite observed ozone data in the same period of 1979-2002 shows that over the TP, the total ozone amount declined in all seasons, and the ozone depleted the most compared with the situations in other regions in the same latitudes. It is proposed that the difference between the ozone depletion over the TP and that over other regions in the same latitudes may lead to the difference in air temperature changes. Because of the aggravated depletion of ozone over the TP, less (more) ultraviolet radiation was absorbed in the upper troposphere to lower stratosphere (lower to middle troposphere) over the TP, which favored a stronger cooling in the upper troposphere to lower stratosphere, and an intenser heating in the lower to middle troposphere over the TP. Therefore, the comparatively more depletion of ozone over the TP is possibly a reason for the difference between the air temperature changes over the TP and those over other regions in the same latitudes.展开更多
The temperature variability over multidecadal and longer timescales(e.g., the cold epochs in the late 15 th, 17 th, and early 19 th centuries) is significant and dominant in the millennium-long, large-scale reconstruc...The temperature variability over multidecadal and longer timescales(e.g., the cold epochs in the late 15 th, 17 th, and early 19 th centuries) is significant and dominant in the millennium-long, large-scale reconstructions and model simulations;however, their temporal patterns in the reconstructed and simulated temperature series are not well understood and require a detailed assessment and comparison. Here, we compare the reconstructed and simulated temperature series for the Northern Hemisphere(NH) at multidecadal and longer-term timescales(>30 years) by evaluating their covariance, climate sensitivity and amplitude of temperature changes. We found that covariances between different reconstructions or between reconstructions and simulations are generally high for the whole period of 850–1999 CE, due to their similar long-term temporal patterns. However,covariances between different reconstructions or between reconstructions and simulations steadily decline as time series extends further back in time, becoming particularly small during Medieval times. This is related to the large uncetainties in the reconstructions caused by the decreased number of proxy records and sample duplication during the pre-instrumental periods.Reconstructions based solely on tree-ring data show higher skill than multiproxy reconstructions in capturing the amplitude of volcanic cooling simulated by models. Meanwhile, climate models have a shorter recovery(i.e., lag) in response to the cooling caused by volcanic eruptions and solar activity minima, implying the lack of some important feedback mechanisms between external forcing and internal climate processes in climate models. Amplitudes of temperature variations in the latest published tree-ring reconstructions are comparable to those of the multiproxy reconstructions. We found that the temperature difference between the Medieval Climate Anomaly(950–1250 CE) and the Little Ice Age(1450–1850 CE) is generally larger in proxybased reconstructions than in model simulations, but the reason is unclear.展开更多
The U75V 60 kg/m heavy rail samples were heated to 900 ℃ in a resistance furnace for a fixed duration of 50 min. Under this condition, the samples were austenitized totally. Then, the samples were dragged out of furn...The U75V 60 kg/m heavy rail samples were heated to 900 ℃ in a resistance furnace for a fixed duration of 50 min. Under this condition, the samples were austenitized totally. Then, the samples were dragged out of furnace and cooled for 25 s in the open air. After that, the samples entered into the air spraying channel, and were cooled from the top and both sides by compressed air. During this period, main technical parameters were changed such as the distance between spray nozzles and surface of rail head, air pressure, air spraying time and air temperature. So under laboratory condition, optimal heat-treating parameters of U75V 60 kg/m heavy rail were determined as the distance between spray nozzles and surface of rail head of 15 mm, air pressure of 0.26 MPa, cooling time of 80 s, and air temperature of 28 ℃. The surface temperature at different positions of heavy rail was measured before and after heat treatment, and the temperature changing law was determined. The self tempering occurred on the surface of rail head after heat treatment, and the tempering temperature became the largest (about 3 min) after heat treatment, separately 528, 524 and 536 ℃ at the center, top fillet and bottom fillet of rail head. The heavy rail was cooled in open air after heat treatment; during this period, the temperature gap on the surface of heavy rail became smaller and smaller, and was reduced to zero when being cooled for 20 min.展开更多
The wavelet analysis method is used to analyze the annual and winter temperature data of 98 observation stations in China in eight climate zones during the last 50 years (1961-2009). The periodicities of temperature...The wavelet analysis method is used to analyze the annual and winter temperature data of 98 observation stations in China in eight climate zones during the last 50 years (1961-2009). The periodicities of temperature changes are investigated, and the possible temperature change trends in China in the next 20 years (2012-2029) are also predicted. Our results show that in the inter-annual temperature variability there are pervasive quasi-3- to quasi-4-year cycles, and these cycle changes are relatively steady. The periodic characteristics of the annual temperature changes are clearly different between northern and southern China, and our period superimposition extrapolation shows that both annual and winter temperatures in China will continue to increase in the next 20 years, more so in northern China and in the Qinghai-Xizang Plateau (QXP) than in the southern region, except in the southwest. If temperatures follow historic increasing linear trends, the overall temper- ature is expected to increase by 1℃ between 2010 and 2029.展开更多
Using the NCEP/NCAR reanalysis data (Version 1.0) and the observation data of China from January 1951 to February 2007, a new index of East Asian winter monsoon circulation (I EAWM) was defined based on the compar...Using the NCEP/NCAR reanalysis data (Version 1.0) and the observation data of China from January 1951 to February 2007, a new index of East Asian winter monsoon circulation (I EAWM) was defined based on the comparison of previous different winter monsoon indices and circulation factors influencing the winter climate over China. Its relationships with winter temperature over China and large-scale circulation were analyzed. Results show that IEAWM can successfully describe the variation of China's mainland winter temperature and the East Asian winter monsoon (EAWM) system. This index reflects the integrated effect of the circulations over high and low latitudes and the thermal difference between the continent and the ocean. While in the previous studies, most monsoon indices only describe the single monsoon member. The IEAWM is a good indicator of the intensity of the EAWM. Positive values of/EAWM correspond to the strong EAWM, the stronger Siberian high and East Asian trough than normal , and the strengthening of the meridional shear of 500-hPa zonal wind between high and low latitudes over East Asia, and therefore, the southward cold advection becomes stronger and leads to the decrease in surface temperature over China; and vice versa. The IEAWM inter decadal change is obviously positive before the mid-1980s, but negative since the mid-1980s, in good agreement with the fact of the winter warming in China after 1985.展开更多
基金Project supported by the National Natural Science Foundation of China (Nos.12172326 and 11972319)the National Key Research and Development Program of China (No.2020YFA0711700)the Natural Science Foundation of Zhejiang Province of China (No.LR21A020002)。
文摘Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor devices.PS fiber-like structures have wide applications in multi-functional semiconductor devices.In this paper,a one-dimensional(1D)theoretical model is established to describe the piezotronic responses of a PS fiber under gradient temperature changes.The theoretical model aims to explain the mechanism behind the resistance change caused by such gradient temperature changes.Numerical results demonstrate that a gradient temperature change significantly affects the physical fields within the PS fiber,and can induce changes in its surface resistance.It provides important theoretical guidance on the development of piezotronic devices that are sensitive to temperature effects.
基金supported by the National Basic Research Program of China (Grant Nos. 2010CB955703 and 2011CB403405)the Public Meteorology Special Foundation of MOST (Grant No. GYHY200906020)
文摘New estimations of radiative forcing due to CO2 were calculated using updated concentration data of CO2 and a high-resolution radiative transfer model. The stratospheric adjusted radiative forcing (ARF) due to CO2 from the year 1750 to the updated year of 2010 was found to have increased to 1.95 W m-2, which was 17% larger than that of the IPCC's 4th Assessment Report because of the rapid increase in CO2 concentrations since 2005. A new formula is proposed to accurately describe the relationship between the ARF of CO2 and its concentration. Furthermore, according to the relationship between the ARF and surface temperature change, possible changes in equilibrium surface temperature were estimated under the scenarios that the concentration of CO2 increases to 1.5, 2, 2.5, 3, 3.5 and 4 times that of the concentration in the year 2008. The result was values of +2.2℃, +3.8℃, +5.1℃, +6.2℃, +7.1℃ and +8.0℃ respectively, based on a middle-level climate sensitivity parameter of 0.8 K (W m 3)-1. Non-equilibrium surface temperature changes over the next 500 years were also calculated under two kinds of emission scenarios (pulsed and sustained emissions) as a comparison, according to the Absolute Global Temperature change Potential (AGTP) of CO2. Results showed that CO2 will likely continue to contribute to global warming if no emission controls are imposed, and the effect on the Earth-atmosphere system will be difficult to restore to its original level.
基金supported by National Natural Science Foundation of China (Grant Nos. 40575019, 40730949)the U.K. Natural Environ-ment Research Council (NERC)
文摘Using a detailed, fully coupled chemistry climate model (CCM), the effect of increasing stratospheric H20 on ozone and temperature is investigated. Different CCM time-slice runs have been performed to investigate the chemical and radiative impacts of an assumed 2 ppmv increase in H20. The chemical effects of this H20 increase lead to an overall decrease of the total column ozone (TCO) by ~1% in the tropics and by a maximum of 12% at southern high latitudes. At northern high latitudes, the TCO is increased by only up to 5% due to stronger transport in the Arctic. A 2-ppmv H2O increase in the model's radiation scheme causes a cooling of the tropical stratosphere of no more than 2 K, but a cooling of more than 4 K at high latitudes. Consequently, the TCO is increased by about 2%-6%. Increasing stratospheric H2O, therefore, cools the stratosphere both directly and indirectly, except in the polar regions where the temperature responds differently due to feedbacks between ozone and H2O changes. The combined chemical and radiative effects of increasing H2O may give rise to more cooling in the tropics and middle latitudes but less cooling in the polar stratosphere. The combined effects of H2O increases on ozone tend to offset each other, except in the Arctic stratosphere where both the radiative and chemical impacts give rise to increased ozone. The chemical and radiative effects of increasing H2O cause dynamical responses in the stratosphere with an evident hemispheric asymmetry. In terms of ozone recovery, increasing the stratospheric H2O is likely to accelerate the recovery in the northern high latitudes and delay it in the southern high latitudes. The modeled ozone recovery is more significant between 2000 ~2050 than between 2050~2100, driven mainly by the larger relative change in chlorine in the earlier period.
基金the National Natural Science Foundation of China (Grant No.30070606) and Graduate Cultivation Foundation of Beijing Forestry University(Grant No.304)
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA050800)the Key Program of the Chinese Academy of Sciences (Grant No. KJZD-EW-TZ-G10)the National Natural Science Foundation of China (Grant No.41671201 and 91525101)
文摘This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation in China has exhibited significant 50–70-yr, 100–120-yr, and 200–250-yr cycles. Results also show that the amplitudes of decadal and centennial temperature variation were 1.3℃ and 0.7℃, respectively, with the latter significantly correlated with long-term changes in solar radiation, especially cold periods, which correspond approximately to sunspot minima. The most rapid warming in China occurred over AD 1870–2000, at a rate of 0.56°± 0.42℃(100 yr)^(-1); however, temperatures recorded in the 20 th century may not be unprecedented for the last 2000 years, as data show records for the periods AD 981–1100 and AD1201–70 are comparable to the present. The ensemble means of dryness/wetness spatial patterns in eastern China across all centennial warm periods illustrate a tripole pattern: dry south of 25°N, wet from 25°–30°N, and dry to the north of 30°N. However, for all centennial cold periods, this spatial pattern also exhibits a meridional distribution. The increase in precipitation over the monsoonal regions of China associated with the 20 th century warming can primarily be attributed to a mega El Nino–Southern Oscillation and the Atlantic Multidecadal Oscillation. In addition, a significant association between increasing numbers of locusts and dry/cold conditions is found in eastern China. Plague intensity also generally increases in concert with wetness in northern China, while more precipitation is likely to have a negative effect in southern China.
文摘A series of alloys (Gd1-xHox)5Si4(x=0, 0.05, 0.15, 0.25) have been prepared. Adiabatic temperature changes of(Gd1-xHox)5Si4 alloys is exactly investigated by a control and analysis system for ΔH=1.4 T, and the measurement results are trustworthy. Curie temperatures of these alloys are tunable in a wide temperature region, and decrease almost linearly with the increasing of Ho content. Magnetic entropy changes in the (Gd1-xHox)Si4 compounds are about 2.35 J/(kg·K) when magnetic field change are 0~1.4 T. The adiabatic temperatures of these alloys at Curie Points are larger than 1 K about 40% of that of Gd in a field change 0~1.4 T, and the curves of ΔTad are as wide as that of Gd. The relative cooling power RCP(S) or RCP(T) of these alloys are about 0.5~0.7 J·cm-3 and 42~50 K2 on the field 0~1.4 T, about 58% and 55% of that of Gd respectively. These alloys are potential magnetic refrigerants working in a refrigerator at room temperatures.
基金supported by the National Natural Science Foundation of China(Nos.12172281 and 11972284)the Distinguished Young Scholars of Shaanxi Province of China(No.2019JC-29)+2 种基金the Foundation Strengthening Programme Technical Area Fund of Shaanxi Province of China(No.2021-JCJQ-JJ-0565)the Science and Technology Innovation Team of Shaanxi Province of China(No.2022TD-61)the Youth Innovation Team of Shaanxi Universities and Doctoral Dissertation Innovation Fund of Xi’an University of Technology of China(Nos.252072016 and 252072115)。
文摘Solvent-free nanofluids hold promise for many technologically significant applications.The liquid-like behavior,a typical rheological property of solvent-free nanofluids,has aroused considerable interests.However,there has been still lack of efficient methods to predict and control the liquid-like behavior of solvent-free nanofluids.In this paper,we propose a semi-discrete dynamic system with stochastic excitation describing the temperature change effects on the rheological property of multiwall carbon nanotubes(MWCNTs)modified by grafting sulfonic acid terminated organosilanes as corona and tertiary amine as canopy,which is a typical covalent-type solvent-free nanofluid system.The vibration of the grafting branches is simulated by employing a structure-preserving approach,and the shear force of grafting branches at the fixed end is computed subsequently.By taking the shear forces as an excitation acting on the MWCNTs,the axial motion of the MWCNTs is solved with the 7-point Gauss-Kronrod quadrature rule.The critical temperature associated with the appearance of the liquid-like behavior as well as the upper bound of the moving speed of the modified MWCNTs is determined,which can be used to predict and control the liquid-like behavior of the modified MWCNTs in engineering applications.
文摘Abstract: In 1876 Blytt proposed a post-glacial climatic classification, maintaining that the then temperature fluctuated 1–2°C higher or lower than that today. Lamb (1969) held that in Europe “the axis of the subtropical high pressure belt was generally displaced north by about 10° latitudes” during the Hypsithermal and that the temperature was three to six times higher than that in the postglacial period.
基金Supported by the Key Project of Provincial Natural Science Research for Colleges and Universities in Anhui Province, China ( KJ2013A244)
文摘[Objective] The study aimed to discuss the effects of coal mining subsided water area on temperature change in Huaibei coal mine. [Method] Based on the data of monthly temperature from 1957 to 2007 recorded by Suixi (coal mining subsided water area) and Fuyang stations (control), the effects of coal mining subsided water area on temperature change in Huaibei coal mine were discussed using linear trend estimation and comparative analysis methods. [Result] Spring, autumn, winter and annual average temperatures of coal mining subsided water area (Suixi) were increased in the last 51 years, and the increase of winter temperature was mostly significant with a tendency rate of 0.49 ℃/10 a. Meanwhile, annual temperature range of coal mining subsided water area was decreased from 1957 to 2007. Temperatures of Suixi in four seasons were lower than those of Fuyang from the 1960s to 1990s, and temperatures of coal mining subsided water area (Suixi) were higher than those of Fuyang in spring, autumn and winter but lower than those of Fuyang in summer from 2000 to 2007. [ Result] Coal mining subsided water area had certain effects on temperature change of Huaibei coal mine.
基金Supported by Guangxi Natural Science Foundation ProjectChina(2013GXNSFAA019283)
文摘The spatial and temporal variation characteristics of temperature were analyzed by using climate tendency coefficient, climatic inclination rate and Mann-Kendall catastrophe test,based on the annual and seasonal average temperatures of 28 meteorological stations in Guangxi from 1971 to 2013. Under the global warming,the annual and seasonal average temperatures in typical karst area of Guangxi had an increasing trend. The cli- mate inclination rate of annual average temperature reached a significant level, which was about 0.17 ℃/10 a, and the year of abrupt changes ap- peared in 1996. About seasonal temperature's trend, average temperatures of all the four seasons had an increase trend in the past 43 years, and the significant increase was happened in autumn with the temperature increase rate of 0.28 ℃/10 a, followed by increase rate of average tempera- ture in winter with 0.25 ℃/10 a. A long-term warming tendency was observed by seasonal average temperature from 1971 to 2013, especially dur- ing 2002 - 2013.
文摘Respiratory disease and cardio-cerebral vascular disease frequently occur in Anyang City. In this paper, by comparing incidence num- bers of respiratory disease and cardio-cerebral vascular disease in Anyang People's Hospital during 2010 -2012 with seasonal change of local tem- perature,it is found that they have obvious relationship, which has very important significance for preventing respiratory disease and cardio-cerebral vascular disease in the future.
基金Supported by National Natural Science Foundation of Yunnan Province (2011FB009)
文摘[Objective] The aim was to study air temperature changes and urbanization contribution ration in Kunming City in recent 50 years. [ Method] The observation data of air temperature series from Kunming station and other four surrounding meteorological stations were used to in- vestigate air temperature variation in Kunming station affected by urbanization during 1960 -2009. [ Result] The trend slope of mean annual temper- ature was 0.402 ~(3/10 a in Kunming station and 0. 103 ~C/10 a in other four surrounding meteorological stations, and the increasing magnitude of air temperature in Kunming station was more than 3 times that of average global warming in the past 50 year. The effect of urbanization on mean an- nual temperature in Kunming station started from 1990. During 1990 -1994, the increasing contribution rate of urbanization to air temperature in Kunming station was less than 40%. From 1995 to 2009, the contribution ratio was more than 50%, up to about 60% in all seasons. Urban heat is- land effect in Kunming station was intensified with the development of urbanization. In addition, the warming rate caused by urban heat island effect in Kunming station was the greatest in dry season, followed by mean annual temperature, and it was the weakest in rainy season. [ Conclusion] The study provided theoretical foundation for future research.
基金supported by the Science and Technology Fundamental Resources Investigation Program of China (2017FY101201).
文摘The short-term temperature fluctuation caused by global climate change is one of the risk factors affecting public health.Exploring the association between temperature fluctuation and diseases,which has received relatively limited research attention,can contribute to enhancing awareness of health risks and taking timely measures for health risk alert and management.Therefore,this study aims to investigate the relationship between temperature change between neighboring days(TCN)and hospitalizations,identify diseases sensitive to extreme TCN,and evaluate the related disease burden.We collected meteorological and hospitalization data from 2014 to 2019 in 23 sites of China to explore the impact of TCN on hospitalizations.We first quantified site-specific associations between TCN and hospitalizations and then conducted meta-analysis to pool the results,to assess the relative risk of extreme TCN for susceptible diseases,and to estimate the related disease burden attributed to TCN.Stratified analyses were undertaken by age,sex,and disease type.Results showed that all-cause hospital admission was significantly linked to TCN.A negative TCN(below-1.9℃)in the cool season and a positive TCN(above 1.0℃)in the warm season increased the risk of hospitalization.People aged 15-64 years,men,and patients with musculoskeletal system or connective tissue diseases were more sensitive to extremely negative TCN during the cool season.People aged over 65 years,men,and patients with respiratory diseases were more sensitive to extremely positive TCN during the warm season.The attributable fraction to all-cause hospitalization from negative TCN in the cool season was 2.05%(95%CI:-0.90%,4.53%)and from positive TCN in the warm season was 5.79%(95%CI:2.98%,8.31%).Circulatory diseases in the cool season and respiratory diseases in the warm season had the highest disease burden.Our findings indicate that awareness of TCN and its health risks should be promoted and evidence-informed policies are needed to reduce the risk of TCN.
基金supported by the National Natural Science Foundation of China(21977086,82260691,and 21867018)“Double tops”from Yunnan Province and Yunnan University(202201BF070001-012)the Yunnan Innovative Research Team for Discovery and Biosynthesis of Bioactive Natural Products(2018HC012)。
文摘The discovery of biological activities of natural products plays a vital part in drug development.The mechanism by which organisms respond to temperature changes via biosynthesis of natural products remained largely cryptic.A thermophilic fungus under cold stress turned black and accumulated a polyketide metabolite 1 and lipid mass.Deficiency in 1 caused melanin loss and accumulated extra lipid mass,unexpectedly leading to seriously damaged mitochondria diagnostic for ferroptosis.Further analysis revealed that lipid mass induced by cold stress intensively increased ferroptosis risk and 1 functioned as cell wall reinforcer against mass lipid accumulation and as reactive oxygen species scavenger against lipid peroxidation.We also found that melanin in mice lowered lipid level but enhanced animal resistance to cold stress.Treatment with melanin precursors significantly increased mouse cell survival rate under cold stress.Our results unveiled a metabolite-lipid-ferroptosis-cold relationship,which provided mechanistic insights into the functions of most common metabolites and into diseases related to cold stress.These findings opened a perspective for developing anti-cold and anti-ferroptosis therapeutics and agents.
基金financially sponsored by the National Natural Science Foundation of China(41967052)the Graduate Students’Research&Innovation Fund of Inner Mongolia Normal University(CXJJS20117)the Graduate Education Innovation Program Funded Project of Inner Mongolia Autonomous Region(SZ2020119)。
文摘Studying the abrupt change of winter temperature(ACWT)over the Mongolian Plateau(MP,including Inner Mongolia Autonomous Region and State of Mongolia)is of great significance for understanding the spatiotemporal distribution of temperature and the mechanism of global climate change.Monthly temperature data during 1961–2017was collected,and the abrupt change point was determined by the Mann–Kendall test and sliding ttest,to analyze the characteristics and causes of ACWT.The results showed that(a)The winter temperature has rapidly increased with a trend of 0.41℃/10a,which was significantly higher than that of the rest area of Chinese mainland,indicating that climate change in the MP was more sensitive to global warming.(b)The abrupt change point occurred in 1988,with temperature of-15.5℃and-14.1℃before and after abrupt change,respectively.The ACWT in 50°N was 1–3 years later than that in 40°N,and the isotherms of different temperatures moved northward by 10–200 km,especially-16℃isotherms moved approximately 200 km northward after 1988.(c)The Arctic Oscillation(AO)and Mongolian High(MH)anomaly affects winter temperature over the MP.When the AO is unusually strong,the MH and East Asian winter monsoon are weak,and southerly winds prevail in most regions,which is not conducive to the cold air developing southward,leading to higher winter temperature in the MP.Overwise,abnormally northerly winds prevail and temperature is low.Meanwhile,the abrupt change time of AO occurred in 1987 before winter temperature.It shows that the AO indirectly causes winter temperatures to rise by influencing the MH and is also the main driving factor of ACWT.
基金Supported by the National Science Foundation of China under Grant No. 40675058Open Laboratory of Chengdu Institute of Plateau Meteorology, China Meteorological Administration under Grant No. LPM2008007
文摘Using radiosonde and satellite observations, we investigated the trends of air temperature changes over the Tibetan Plateau (TP) in comparison with those over other regions in the same latitudes from 1979 to 2002. It is shown that Over the TP, the trends of air temperature changes in the upper troposphere to lower stratosphere were out of phase with those in the lower to middle troposphere. Air temperature decreased and a decreasing trend appeared in the upper troposphere to lower stratosphere. The amplitude of the annual or seasonal mean temperature decreases over the TP was larger than that over the whole globe. In the lower to middle troposphere over the TP, temperature increased, and the increasing trend was stronger than that over the non-plateau regions in the same latitudes in the eastern part of China. Meanwhile, an analysis of the satellite observed ozone data in the same period of 1979-2002 shows that over the TP, the total ozone amount declined in all seasons, and the ozone depleted the most compared with the situations in other regions in the same latitudes. It is proposed that the difference between the ozone depletion over the TP and that over other regions in the same latitudes may lead to the difference in air temperature changes. Because of the aggravated depletion of ozone over the TP, less (more) ultraviolet radiation was absorbed in the upper troposphere to lower stratosphere (lower to middle troposphere) over the TP, which favored a stronger cooling in the upper troposphere to lower stratosphere, and an intenser heating in the lower to middle troposphere over the TP. Therefore, the comparatively more depletion of ozone over the TP is possibly a reason for the difference between the air temperature changes over the TP and those over other regions in the same latitudes.
基金supported by the National Key R&D Program of China (Grant No. 2017YFA0603302)supported by the National Natural Science Foundation of China (Grant Nos. 41888101 & 41602192 & 41977383)+4 种基金the Belmont Forum and JPI-Climate, Collaborative Research Action “INTEGRATE” (Grant No. 41661144008)support by the Youth Innovation Promotion Association Foundation of the Chinese Academy of Sciences (Grant No. 2018471)supported by the National Natural Science Foundation (Grant No. 41901095)supported by the National Natural Science Foundation (Grant No. 41877440)supported by Opening Fund of Key Laboratory of Desert and Desertification, Chinese Academy of Sciences (Grant No. KLDD-2019-04)。
文摘The temperature variability over multidecadal and longer timescales(e.g., the cold epochs in the late 15 th, 17 th, and early 19 th centuries) is significant and dominant in the millennium-long, large-scale reconstructions and model simulations;however, their temporal patterns in the reconstructed and simulated temperature series are not well understood and require a detailed assessment and comparison. Here, we compare the reconstructed and simulated temperature series for the Northern Hemisphere(NH) at multidecadal and longer-term timescales(>30 years) by evaluating their covariance, climate sensitivity and amplitude of temperature changes. We found that covariances between different reconstructions or between reconstructions and simulations are generally high for the whole period of 850–1999 CE, due to their similar long-term temporal patterns. However,covariances between different reconstructions or between reconstructions and simulations steadily decline as time series extends further back in time, becoming particularly small during Medieval times. This is related to the large uncetainties in the reconstructions caused by the decreased number of proxy records and sample duplication during the pre-instrumental periods.Reconstructions based solely on tree-ring data show higher skill than multiproxy reconstructions in capturing the amplitude of volcanic cooling simulated by models. Meanwhile, climate models have a shorter recovery(i.e., lag) in response to the cooling caused by volcanic eruptions and solar activity minima, implying the lack of some important feedback mechanisms between external forcing and internal climate processes in climate models. Amplitudes of temperature variations in the latest published tree-ring reconstructions are comparable to those of the multiproxy reconstructions. We found that the temperature difference between the Medieval Climate Anomaly(950–1250 CE) and the Little Ice Age(1450–1850 CE) is generally larger in proxybased reconstructions than in model simulations, but the reason is unclear.
文摘The U75V 60 kg/m heavy rail samples were heated to 900 ℃ in a resistance furnace for a fixed duration of 50 min. Under this condition, the samples were austenitized totally. Then, the samples were dragged out of furnace and cooled for 25 s in the open air. After that, the samples entered into the air spraying channel, and were cooled from the top and both sides by compressed air. During this period, main technical parameters were changed such as the distance between spray nozzles and surface of rail head, air pressure, air spraying time and air temperature. So under laboratory condition, optimal heat-treating parameters of U75V 60 kg/m heavy rail were determined as the distance between spray nozzles and surface of rail head of 15 mm, air pressure of 0.26 MPa, cooling time of 80 s, and air temperature of 28 ℃. The surface temperature at different positions of heavy rail was measured before and after heat treatment, and the temperature changing law was determined. The self tempering occurred on the surface of rail head after heat treatment, and the tempering temperature became the largest (about 3 min) after heat treatment, separately 528, 524 and 536 ℃ at the center, top fillet and bottom fillet of rail head. The heavy rail was cooled in open air after heat treatment; during this period, the temperature gap on the surface of heavy rail became smaller and smaller, and was reduced to zero when being cooled for 20 min.
基金supported by the National Natural Sci-ence Foundation of China(NSFC)(Grant Nos.41071028,41275061)the Public Benefit(Meteorology)Re-search Foundation of China(Grant No.GYHY201006035)
文摘The wavelet analysis method is used to analyze the annual and winter temperature data of 98 observation stations in China in eight climate zones during the last 50 years (1961-2009). The periodicities of temperature changes are investigated, and the possible temperature change trends in China in the next 20 years (2012-2029) are also predicted. Our results show that in the inter-annual temperature variability there are pervasive quasi-3- to quasi-4-year cycles, and these cycle changes are relatively steady. The periodic characteristics of the annual temperature changes are clearly different between northern and southern China, and our period superimposition extrapolation shows that both annual and winter temperatures in China will continue to increase in the next 20 years, more so in northern China and in the Qinghai-Xizang Plateau (QXP) than in the southern region, except in the southwest. If temperatures follow historic increasing linear trends, the overall temper- ature is expected to increase by 1℃ between 2010 and 2029.
基金Supported jointly by the National Natural Science Foundation of China (40505014)China Meteorological Administration (CMATG2005M04) and GYHY 200706010.
文摘Using the NCEP/NCAR reanalysis data (Version 1.0) and the observation data of China from January 1951 to February 2007, a new index of East Asian winter monsoon circulation (I EAWM) was defined based on the comparison of previous different winter monsoon indices and circulation factors influencing the winter climate over China. Its relationships with winter temperature over China and large-scale circulation were analyzed. Results show that IEAWM can successfully describe the variation of China's mainland winter temperature and the East Asian winter monsoon (EAWM) system. This index reflects the integrated effect of the circulations over high and low latitudes and the thermal difference between the continent and the ocean. While in the previous studies, most monsoon indices only describe the single monsoon member. The IEAWM is a good indicator of the intensity of the EAWM. Positive values of/EAWM correspond to the strong EAWM, the stronger Siberian high and East Asian trough than normal , and the strengthening of the meridional shear of 500-hPa zonal wind between high and low latitudes over East Asia, and therefore, the southward cold advection becomes stronger and leads to the decrease in surface temperature over China; and vice versa. The IEAWM inter decadal change is obviously positive before the mid-1980s, but negative since the mid-1980s, in good agreement with the fact of the winter warming in China after 1985.