The development of efficient and clean heating technologies is crucial for reducing carbon emissions in regions with severe cold regions.This research designs a novel two-stage phase change heat storage coupled solar-...The development of efficient and clean heating technologies is crucial for reducing carbon emissions in regions with severe cold regions.This research designs a novel two-stage phase change heat storage coupled solar-air source heat pump heating system structure that is specifically designed for such regions.The two-stage heat storage device in this heating system expands the storage temperature range of solar heat.The utilization of the two-stage heat storage device not onlymakes up for the instability of the solar heating system,but can also directlymeet the building heating temperature,and can reduce the influence of low-temperature outdoor environments in severe cold regions on the heating performance of the air source heat pump by using solar energy.Therefore,the two-stage phase change heat storage coupled to the solar energy-air source heat pump heating system effectively improves the utilization rate of solar energy.A numerical model of the system components and their integration was developed using TRNSYS software in this study,and various performance aspects of the system were simulated and analyzed.The simulation results demonstrated that the two-stage heat storage device can effectively store solar energy,enabling its hierarchical utilization.The low-temperature solar energy stored by the two-stage phase change heat storage device enhances the coefficient of performance of the air source heat pump by 11.1%in severe cold conditions.Using the Hooke-Jeeves optimization method,the annual cost and carbon emissions are taken as optimization objectives,with the optimized solar heat supply accounting for 52.5%.This study offers valuable insights into operational strategies and site selection for engineering applications,providing a solid theoretical foundation for the widespread implementation of this system in severe cold regions.展开更多
[Objective] The aim of the study was to find out the cold/warm change characteristics in crop growing season and their relationship with food production in Heilongjiang Province.[Method] The temporal and spatial varia...[Objective] The aim of the study was to find out the cold/warm change characteristics in crop growing season and their relationship with food production in Heilongjiang Province.[Method] The temporal and spatial variation on the accumulated temperature steadily above 10 ℃ and its lasting days,the beginning date,the ending dates were investigated,and the relationship between food production and cold/warm climate in Heilongjiang Province during 1961-2009 was further analyzed.[Result] The results showed that the provincial average accumulated temperature steadily above 10 ℃ has increased by 355.4 ℃,the lasting days of accumulated temperature steadily above 10 ℃ has extended by 13d,and the beginning date has advanced by 8 d,while the ending date has delayed by 5 d in Heilongjiang Province during 49 years.Climate warming began from the 1980s,and the most significant period of climate warming was after the 1990s.The food production is closely related to cold/warm climate in Heilongjiang Province.[Conclusion] The climate warming was significant in crop growing season of Heilongjiang Province in the past 49 years,providing more favorable climatic conditions for the agricultural production.展开更多
A cold rolled dual phase （DP） steel with the C-Si-Mn alloy system was trial-produced in the laboratory, utilizing a Gleeble-3800 thermal simulator. The effects of continuous annealing parameters on the mechanical pr...A cold rolled dual phase （DP） steel with the C-Si-Mn alloy system was trial-produced in the laboratory, utilizing a Gleeble-3800 thermal simulator. The effects of continuous annealing parameters on the mechanical properties and microstructures of the DP steel were investigated by mechanical testing and microstructure observation. The results show that soaking between 760 and 820℃ for more than 80 s, rapid cooling at the rate of more than 30℃/s from the quenching temperature between 620 and 680℃, and overaging lower than 300℃ are beneficial for the mechanical properties of DP steels. An appropriate proportion of the two phases is one of the key factors for the favorable properties of DP steels. If the volume fraction of martensite and, thereby, free dislocations are deficient, the tensile strength and n value of DP steels will decrease, whereas, the yield strength will increase. But if the volume fraction of martensite is excessive to make it become a dominant phase, the yield and tensile strength will increase, whereas, the elongation will decrease obviously. When rapid cooling rate is not fast enough, pearlite or cementite will appear, which will degrade the mechanical properties. Even though martensite is sufficient, if it is decomposed in high temperature tempering, the properties will he unsatisfied.展开更多
INTRODUCTIONAlthough liver transplantation for irreversible liverdiseases is increasingly prevalent worldwide,patientdie while waiting for donors because of organshortages.One important problem commonlyencountered is ...INTRODUCTIONAlthough liver transplantation for irreversible liverdiseases is increasingly prevalent worldwide,patientdie while waiting for donors because of organshortages.One important problem commonlyencountered is that fatty livers often affect theoutcome of liver transplantation.It is reported thatthe incidence of abnormal fatty livers in autopsiesafter accidental death ranged from 15% to 24%.Since fatty livers may result in a primarynonfunction (PNF)liver graft,which contributes展开更多
In the first half of winter 2020/21,China has experienced an extremely cold period across both northern and southern regions,with record-breaking low temperatures set in many stations of China.Meanwhile,a moderate La ...In the first half of winter 2020/21,China has experienced an extremely cold period across both northern and southern regions,with record-breaking low temperatures set in many stations of China.Meanwhile,a moderate La Niña event which exceeded both oceanic and atmospheric thresholds began in August 2020 and in a few months developed into its mature phase,just prior to the 2020/21 winter.In this report,the mid−high-latitude large-scale atmospheric circulation anomalies in the Northern Hemisphere,which were forced by the negative phase of Arctic Oscillation,a strengthened Siberian High,an intensified Ural High and a deepened East Asian Trough,are considered to be the direct reason for the frequent cold surges in winter 2020/21.At the same time,the synergistic effect of the warm Arctic and the cold tropical Pacific(La Niña)provided an indispensable background,at a hemispheric scale,to intensify the atmospheric circulation anomalies in middle-to-high latitudes.In the end,a most recent La Niña prediction is provided and the on-coming evolution of climate is discussed for the remaining part of the 2020/21 winter for the purpose of future decision-making and early warning.展开更多
Cold rolling and heat-treatment were used for the grain refinement of GH4169 superalloy plate.The effects of cold rolling reduction ratio and heat-treatment time on the precipitatedδphase,and the effects ofδ-phase c...Cold rolling and heat-treatment were used for the grain refinement of GH4169 superalloy plate.The effects of cold rolling reduction ratio and heat-treatment time on the precipitatedδphase,and the effects ofδ-phase content and morphology on the mechanical properties of the GH4169 alloy plates,are studied.The results demonstrate that coldrolling can promote the precipitation of theδphase and its transformation from theδ-Ni3Nb phase to theδ-NbNi4 phase.The comprehensive properties of the alloy are better when the heat treatment time is 1 h,with 132 MPa increase in the tensile strength and only 2.9%decrease in the elongation relative to those of the original material.The mechanical properties of the alloy are shown to change greatly with the change in theδ-phase morphology.展开更多
An unprecedented cold wave intruded into East Asia in early January 2021 and led to record-breaking or historical extreme low temperatures over vast regions.This study shows that a major stratospheric sudden warming(S...An unprecedented cold wave intruded into East Asia in early January 2021 and led to record-breaking or historical extreme low temperatures over vast regions.This study shows that a major stratospheric sudden warming(SSW)event at the beginning of January 2021 exerted an important influence on this cold wave.The major SSW event occurred on 2 January 2021 and subsequently led to the displacement of the stratospheric polar vortex to the East Asian side.Moreover,the SSW event induced the stratospheric warming signal to propagate downward to the mid-to-lower troposphere,which not only enhanced the blocking in the Urals-Siberia region and the negative phase of the Arctic Oscillation,but also shifted the tropospheric polar vortex off the pole.The displaced tropospheric polar vortex,Ural blocking,and another downstream blocking ridge over western North America formed a distinct inverted omega-shaped circulation pattern(IOCP)in the East Asia-North Pacific sector.This IOCP was the most direct and impactful atmospheric pattern causing the cold wave in East Asia.The IOCP triggered a meridional cell with an upward branch in East Asia and a downward branch in Siberia.The meridional cell intensified the Siberian high and low-level northerly winds,which also favored the invasion of the cold wave into East Asia.Hence,the SSW event and tropospheric circulations such as the IOCP,negative phase of Arctic Oscillation,Ural blocking,enhanced Siberian high,and eastward propagation of Rossby wave eventually induced the outbreak of an unprecedented cold wave in East Asia in early January 2021.展开更多
The expanding curves of two kinds of 1000 MPa ultra-high strength cold rolled dual phase steels,which were C-Si-Mn-Cr and C-Si-Mn-Cr-Mo steel respectively,were detected on Gleeble-1500 thermal-mechanical simulator at ...The expanding curves of two kinds of 1000 MPa ultra-high strength cold rolled dual phase steels,which were C-Si-Mn-Cr and C-Si-Mn-Cr-Mo steel respectively,were detected on Gleeble-1500 thermal-mechanical simulator at different cooling rates.Combined with metallographic and hardness methods,the continuous cooling transformation curves (CCT) of the two steels were obtained.The results showed that Mo could raise the A r3 temperature,and strongly restrain the pearlite and bainite transformation.The reason for this was the interaction that the addition of Mo could increase the chemical driving force of ferrite transformation and the activation energy for the diffusion of carbon in austenite,which could decelerate the ferrite transformation.The hardness of the two steels was similar in the cooling rates range of this experiment and got higher with the increase of the cooling rates.When the cooling rates were above 7 ℃/s,the hardness almost kept constant because the most part of the microstructure was martensite.展开更多
On the basis of NOAA/CPC data of sea surface temperature anomaly in the Nifio regions during Jan. 1950 - Dec. 2003, the wavelet power spectrum of SST were studied with significance and confidence testing at different ...On the basis of NOAA/CPC data of sea surface temperature anomaly in the Nifio regions during Jan. 1950 - Dec. 2003, the wavelet power spectrum of SST were studied with significance and confidence testing at different scales in this paper. It shows that the SST are provided with multi-time scales structure nested one another, and vary on scales of 2 - 7 years, 8 - 20 years and 〉30 years. The most significant variation of the warm and cold episodes is in the 4-year band of period. The power, frequency structure and confidence of the same episode are different in different Nino regions. The intensity of oscillations is increasing at low frequency bands and decreasing at high frequency bands from east to west in the Nino regions, especially after 1970.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
Due to the improvement in fatigue strength of cold-rolled blades,the static recrystallization behavior of cold-rolled Inconel 718 alloy in the solid solution treatment was investigated with the methods of optical micr...Due to the improvement in fatigue strength of cold-rolled blades,the static recrystallization behavior of cold-rolled Inconel 718 alloy in the solid solution treatment was investigated with the methods of optical microscopy and electron backscattered diffraction.The effect ofδphase precipitation on the static recrystallization process was also analyzed.The results show thatδphase preferentially precipitates comparing to static recrystallization.Affecting by theδphase preferential precipitation process,sub-grain migration is the main nucleation mechanism in the static recrystallization of coldrolled Inconel 718 alloy at 980°C.Meanwhile,strain-induced boundary migration also exists as an aided nucleation mechanism when the rolling reduction is less than 30%.展开更多
A winter onshore warm tongue extending from the Yellow Sea Warm Current to the southern Jiangsu coast, and an of fshore cold tongue extending from the southern Jiangsu coast to the southwest of Jeju Island(South Korea...A winter onshore warm tongue extending from the Yellow Sea Warm Current to the southern Jiangsu coast, and an of fshore cold tongue extending from the southern Jiangsu coast to the southwest of Jeju Island(South Korea), are newly identified based on the sea-surface temperature from satellite remote sensing, and further confirmed by the distribution of suspended sediments. In addition, there are two obvious thermal fronts associated with the onshore warm tongue and off shore cold tongue. The narrow gap between the two thermal fronts is supposed to be the pathway for the off shore transport of cold coastal water and suspended sediments. The concurrence of onshore warm and of fshore cold tongues suggests the concurrence of onshore and off shore currents in the western Yellow Sea in winter, which seems to be inconsistent with the previously accepted view that, in winter, the Yellow Sea Coastal Current flows from the Old Huanghe Delta to the southwest of Jeju Island. This distinctive phenomenon helps establish an updated view of the circulation in the western Yellow Sea in winter.展开更多
The purpose of this study was to investigate the effects of a traditional Japanese medicine Goshajinkigan (TJ-107) and Tokishigyakukagoshuyushokyoto (TJ-38) on warm sense threshold, cold sense threshold and the periph...The purpose of this study was to investigate the effects of a traditional Japanese medicine Goshajinkigan (TJ-107) and Tokishigyakukagoshuyushokyoto (TJ-38) on warm sense threshold, cold sense threshold and the peripheral blood flow. 31 healthy volunteers (control group: 9people, TJ-107 group: 12 people, TJ-38group:10 people) were examined. Drugs administered 2.5 g a dose. Analysis was before and after 1 hour dosage. The warm and cold sense threshold in the thenar of the non-handedness site of these subjects was measured using a thermostimulator (Intercross-200, Intercross Co., Tokyo, Japan). The peripheral blood flow in the finger of the non-handedness site of these subjects was measured using a full-field laser perfusion imager (FLPI, Moor Instruments Ltd., England). Control: The vehicle had no significant effect on the warm sense threshold, cold sense threshold and the peripheral blood flow. TJ-107: The warm sense threshold and cold sense threshold were significantly decreased, and the reaction latency of cold sense was significantly shortening. The peripheral blood flow was significantly increased second and third finger at 115.6%, 119.3%, respectively. TJ-38: The cold sense threshold and the reaction latency of cold sense were significantly increased. The peripheral blood flow was significantly increased second and third finger with 114.3%, 112.8%, respectively. These results suggest that TJ-107 and TJ-38 have effects on the changed warm sense threshold, cold sense threshold and increased peripheral blood flow.展开更多
A series of single phase,warm white light emitting phosphors,Gd(P_(x)V_(1−x))O_(4):y at%Sm^(3+),with 1 at%Bi^(3+) doping concentration were synthesized by high temperature solid state method in this work.The experimen...A series of single phase,warm white light emitting phosphors,Gd(P_(x)V_(1−x))O_(4):y at%Sm^(3+),with 1 at%Bi^(3+) doping concentration were synthesized by high temperature solid state method in this work.The experimental results indicate broadband cyan emission of Bi^(3+)and characteristic orange-red emission of Sm^(3+)can be effectively tuned by changing the ratios of PO^(3−)_(4)/VO^(3−)_(4) in Gd(P_(x)V_(1−x))O_(4):1 at%Sm^(3+),1 at%Bi^(3+),and the energy transfer process among VO^(3−)_(4),Sm^(3+),Bi^(3+) also can be adjusted.Based on this,warm white light emitting can be realized by further optimizing the doping concentration of Sm^(3+) in the phosphors.At 423 K,the PL intensity of Gd(P_(0.7)V_(0.3))O_(4):2 at%Sm^(3+),1 at%Bi^(3+) remains~84.3%of the initial value at 293 K,while the measured quantum efficiency is 67.8%.EL spectrum analysis results of the fabricated white light emitting diode(wLED)based on a 310 nm UV-chip and Gd(P_(0.7)V_(0.3))O4:2 at%Sm^(3+),1 at%Bi^(3+)phosphors imply low correlated color temperature(3132 K)and appropriate color-rending index(R_(a)=82.7).These results demonstrate that Gd(P_(0.7)V_(0.3))O4:2 at%Sm^(3+),1 at%Bi^(3+)is a good candidate for manufacturing UV-activated warm white light emitting diodes.展开更多
Influence of severe cold deformation of titanium alloy Ti-1.5%A1-6.8%Mo-4.5%Fe in metastable β condition on the evolution of phase composition, microstructure, and tensile properties during continuous rapid heating w...Influence of severe cold deformation of titanium alloy Ti-1.5%A1-6.8%Mo-4.5%Fe in metastable β condition on the evolution of phase composition, microstructure, and tensile properties during continuous rapid heating was studied. As-deformed alloy was characterized by quasi-amorphous single-phase β condition with an abnormal temperature dependence of electric resistance that was normalized after 48 h exposure at room temperature as a result of isothermal ω phase precipitation. Subsequent rapid heating with a rate of 5 ℃/s caused recovery and recrystallization. Tensile properties of the alloy after different treatments were determined and discussed.展开更多
The rate of warming of Arctic surface temperature is about 2–3 times faster than the global mean surface warming. Increases of ice albedo feedback and water vapor as well as moisture intrusion from outside the Arctic...The rate of warming of Arctic surface temperature is about 2–3 times faster than the global mean surface warming. Increases of ice albedo feedback and water vapor as well as moisture intrusion from outside the Arctic all have major roles in this phenomenon. In contrast to this rapid Arctic warming, in recent decades, stronger cold air outbreaks have occurred more frequently during winter in East Asia than were recorded in the 1990s, resulting in severe socioeconomic impacts. A number of related studies have claimed the increased frequency of these stronger cold air outbreaks is linked to the amplified warming in the Arctic through complicated mechanisms. As there are time lags between the observed Arctic warming and East Asian cold weather response at various scales, understanding the entire chain of processes from the Arctic to East Asia has importance for forecasting winter weather in East Asia. There are two pathways linking Arctic warming with East Asian cold weather events. One is the synoptic-scale pathway in the lower troposphere via strengthening of the Siberian High initiated by Ural blocking. The other is the planetary-scale path through the stratosphere via activation of planetary waves and downward propagation, which weakens the polar vortex. This study briefly reviews the current understanding of the linkage mechanisms between Arctic warming and East Asian winter cold weather.展开更多
Under recent Arctic warming,boreal winters have witnessed severe cold surges over both Eurasia and North America,bringing about serious social and economic impacts.Here,we investigated the changes in daily surface air...Under recent Arctic warming,boreal winters have witnessed severe cold surges over both Eurasia and North America,bringing about serious social and economic impacts.Here,we investigated the changes in daily surface air temperature(SAT)variability during the rapid Arctic warming period of 1988/89–2015/16,and found the daily SAT variance,mainly contributed by the sub-seasonal component,shows an increasing and decreasing trend over eastern Eurasia and North America,respectively.Increasing cold extremes(defined as days with daily SAT anomalies below 1.5 standard deviations)dominated the increase of the daily SAT variability over eastern Eurasia,while decreasing cold extremes dominated the decrease of the daily SAT variability over North America.The circulation regime of cold extremes over eastern Eurasia(North America)is characterized by an enhanced high-pressure ridge over the Urals(Alaska)and surface Siberian(Canadian)high.The data analyses and model simulations show the recent strengthening of the high-pressure ridge over the Urals was associated with warming of the Barents–Kara seas in the Arctic region,while the high-pressure ridge over Alaska was influenced by the offset effect of Arctic warming over the East Siberian–Chukchi seas and the Pacific decadal oscillation(PDO)–like sea surface temperature(SST)anomalies over the North Pacific.The transition of the PDO-like SST anomalies from a positive to negative phase cancelled the impact of Arctic warming,reduced the occurrence of extreme cold days,and possibly resulted in the decreasing trend of daily SAT variability in North America.The multi-ensemble simulations of climate models confirmed the regional Arctic warming as the driver of the increasing SAT variance over eastern Eurasia and North America and the overwhelming effect of SST forcing on the decreasing SAT variance over North America.Therefore,the regional response of winter cold extremes at midlatitudes to the Arctic warming could be different due to the distinct impact of decadal SST anomalies.展开更多
Due to the important role ofδphase's quantity and morphology in the mechanical and fatigue properties of Inconel 718 alloy and its components,it is necessary to renew insights into the effect of cold deformation ...Due to the important role ofδphase's quantity and morphology in the mechanical and fatigue properties of Inconel 718 alloy and its components,it is necessary to renew insights into the effect of cold deformation on theδphase precipitation,especially on the morphology evolution.Therefore,the nucleation and growth behavior ofδphase in cold-rolled Inconel 718 alloy during aging were investigated.The results show that the precipitation rate and volume fraction ofδphase increase with increasing the cold rolling reduction from 10%to 50%.The volume fraction ofδphase reaches equilibrium after 5 h,remaining at 5.98%,6.52%,and 6.79%under different rolling reductions(10%,30%,and 50%),respectively.The nucleation ofδphase mainly occurs on different sites(grain boundaries,new twin boundaries and old twin boundaries)under 10%rolling reduction,whileδphase mainly nucleates on the new grain boundaries of static recrystallization due to 50%rolling reduction.And the growth ofδphase undergoes a process of alternate orientation growth from spherical(nucleation)→short rod(longitudinal orientation growth)→short rod(radial orientation growth)→dynamic equilib-rium.Under 10%rolling reduction,δphase tends to grow into the matrix,while under 50%rolling reduction,the orientation grows faster and is easily affected by the grain boundary curvature.展开更多
A new method for analysis of trace mercury in water samples was developed, based on the combination of preconcentration/separation using dithizone-modified nanometer titanium dioxide （TiO2） as a solid phase extracta...A new method for analysis of trace mercury in water samples was developed, based on the combination of preconcentration/separation using dithizone-modified nanometer titanium dioxide （TiO2） as a solid phase extractant and determination by cold vapor atomic adsorption spectrometry （CVAAS）. Dithizone was dissolved with alcohol and loaded on the surface of nano-sized TiO2 powders by stirring. The static adsorption behavior of Hg^2＋on the dithizone-modified nanoparficles was investigated in detail. It was found that excellent adsorption ratio for Hg^2＋ could be obtained in the pH range of 7-8 with an oscillation time of 15 rain, and a 5 mL of 3.5 mol·L^-1 HCI solution could quantitatively elute Hg^2＋ from nanometer TiO2 powder. Common coexisting ions caused no obvious influence on the determination of mercury. The mechanisms for the adsorption and desorption were discussed. The detection limit （30） for Hg^2＋ was calculated to be 5 ng·L^-1. The proposed method was applied to the determination of Hg^2＋ in a mineral water sample and a Zhujiang River water sample. By the standard addition method, the average recoveries were found to be 94.4%-108.3% with RSD （n = 5） of 2.9%-3.5%.展开更多
基金This work was supported by the project of the Research on Energy Consumption of Office Space in Colleges and Universities under the“Dual Carbon Target”(No.CJ202301006).
文摘The development of efficient and clean heating technologies is crucial for reducing carbon emissions in regions with severe cold regions.This research designs a novel two-stage phase change heat storage coupled solar-air source heat pump heating system structure that is specifically designed for such regions.The two-stage heat storage device in this heating system expands the storage temperature range of solar heat.The utilization of the two-stage heat storage device not onlymakes up for the instability of the solar heating system,but can also directlymeet the building heating temperature,and can reduce the influence of low-temperature outdoor environments in severe cold regions on the heating performance of the air source heat pump by using solar energy.Therefore,the two-stage phase change heat storage coupled to the solar energy-air source heat pump heating system effectively improves the utilization rate of solar energy.A numerical model of the system components and their integration was developed using TRNSYS software in this study,and various performance aspects of the system were simulated and analyzed.The simulation results demonstrated that the two-stage heat storage device can effectively store solar energy,enabling its hierarchical utilization.The low-temperature solar energy stored by the two-stage phase change heat storage device enhances the coefficient of performance of the air source heat pump by 11.1%in severe cold conditions.Using the Hooke-Jeeves optimization method,the annual cost and carbon emissions are taken as optimization objectives,with the optimized solar heat supply accounting for 52.5%.This study offers valuable insights into operational strategies and site selection for engineering applications,providing a solid theoretical foundation for the widespread implementation of this system in severe cold regions.
基金Supported by Program for Science and Technology Development in Heilongjiang Province(GC06C103-05)~~
文摘[Objective] The aim of the study was to find out the cold/warm change characteristics in crop growing season and their relationship with food production in Heilongjiang Province.[Method] The temporal and spatial variation on the accumulated temperature steadily above 10 ℃ and its lasting days,the beginning date,the ending dates were investigated,and the relationship between food production and cold/warm climate in Heilongjiang Province during 1961-2009 was further analyzed.[Result] The results showed that the provincial average accumulated temperature steadily above 10 ℃ has increased by 355.4 ℃,the lasting days of accumulated temperature steadily above 10 ℃ has extended by 13d,and the beginning date has advanced by 8 d,while the ending date has delayed by 5 d in Heilongjiang Province during 49 years.Climate warming began from the 1980s,and the most significant period of climate warming was after the 1990s.The food production is closely related to cold/warm climate in Heilongjiang Province.[Conclusion] The climate warming was significant in crop growing season of Heilongjiang Province in the past 49 years,providing more favorable climatic conditions for the agricultural production.
文摘A cold rolled dual phase （DP） steel with the C-Si-Mn alloy system was trial-produced in the laboratory, utilizing a Gleeble-3800 thermal simulator. The effects of continuous annealing parameters on the mechanical properties and microstructures of the DP steel were investigated by mechanical testing and microstructure observation. The results show that soaking between 760 and 820℃ for more than 80 s, rapid cooling at the rate of more than 30℃/s from the quenching temperature between 620 and 680℃, and overaging lower than 300℃ are beneficial for the mechanical properties of DP steels. An appropriate proportion of the two phases is one of the key factors for the favorable properties of DP steels. If the volume fraction of martensite and, thereby, free dislocations are deficient, the tensile strength and n value of DP steels will decrease, whereas, the yield strength will increase. But if the volume fraction of martensite is excessive to make it become a dominant phase, the yield and tensile strength will increase, whereas, the elongation will decrease obviously. When rapid cooling rate is not fast enough, pearlite or cementite will appear, which will degrade the mechanical properties. Even though martensite is sufficient, if it is decomposed in high temperature tempering, the properties will he unsatisfied.
基金the National Natural Science Foundation of China,No.39470682
文摘INTRODUCTIONAlthough liver transplantation for irreversible liverdiseases is increasingly prevalent worldwide,patientdie while waiting for donors because of organshortages.One important problem commonlyencountered is that fatty livers often affect theoutcome of liver transplantation.It is reported thatthe incidence of abnormal fatty livers in autopsiesafter accidental death ranged from 15% to 24%.Since fatty livers may result in a primarynonfunction (PNF)liver graft,which contributes
基金supported by the national key R&D Program of China(Grant No 2018YFC1505603)the Key Research Program of Frontier Sciences,CAS(Grant No.ZDBS-LY-DQC010)the National Natural Science Foundation of China(Grant Nos.41876012,41861144015).
文摘In the first half of winter 2020/21,China has experienced an extremely cold period across both northern and southern regions,with record-breaking low temperatures set in many stations of China.Meanwhile,a moderate La Niña event which exceeded both oceanic and atmospheric thresholds began in August 2020 and in a few months developed into its mature phase,just prior to the 2020/21 winter.In this report,the mid−high-latitude large-scale atmospheric circulation anomalies in the Northern Hemisphere,which were forced by the negative phase of Arctic Oscillation,a strengthened Siberian High,an intensified Ural High and a deepened East Asian Trough,are considered to be the direct reason for the frequent cold surges in winter 2020/21.At the same time,the synergistic effect of the warm Arctic and the cold tropical Pacific(La Niña)provided an indispensable background,at a hemispheric scale,to intensify the atmospheric circulation anomalies in middle-to-high latitudes.In the end,a most recent La Niña prediction is provided and the on-coming evolution of climate is discussed for the remaining part of the 2020/21 winter for the purpose of future decision-making and early warning.
基金Project(E2019203005)supported by the Natural Science Foundation of Hebei Province,China。
文摘Cold rolling and heat-treatment were used for the grain refinement of GH4169 superalloy plate.The effects of cold rolling reduction ratio and heat-treatment time on the precipitatedδphase,and the effects ofδ-phase content and morphology on the mechanical properties of the GH4169 alloy plates,are studied.The results demonstrate that coldrolling can promote the precipitation of theδphase and its transformation from theδ-Ni3Nb phase to theδ-NbNi4 phase.The comprehensive properties of the alloy are better when the heat treatment time is 1 h,with 132 MPa increase in the tensile strength and only 2.9%decrease in the elongation relative to those of the original material.The mechanical properties of the alloy are shown to change greatly with the change in theδ-phase morphology.
基金jointly supported by the National Natural Science Foundation of China (Grant Nos.41790471, 41991284, and 41875104)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDA20100304).
文摘An unprecedented cold wave intruded into East Asia in early January 2021 and led to record-breaking or historical extreme low temperatures over vast regions.This study shows that a major stratospheric sudden warming(SSW)event at the beginning of January 2021 exerted an important influence on this cold wave.The major SSW event occurred on 2 January 2021 and subsequently led to the displacement of the stratospheric polar vortex to the East Asian side.Moreover,the SSW event induced the stratospheric warming signal to propagate downward to the mid-to-lower troposphere,which not only enhanced the blocking in the Urals-Siberia region and the negative phase of the Arctic Oscillation,but also shifted the tropospheric polar vortex off the pole.The displaced tropospheric polar vortex,Ural blocking,and another downstream blocking ridge over western North America formed a distinct inverted omega-shaped circulation pattern(IOCP)in the East Asia-North Pacific sector.This IOCP was the most direct and impactful atmospheric pattern causing the cold wave in East Asia.The IOCP triggered a meridional cell with an upward branch in East Asia and a downward branch in Siberia.The meridional cell intensified the Siberian high and low-level northerly winds,which also favored the invasion of the cold wave into East Asia.Hence,the SSW event and tropospheric circulations such as the IOCP,negative phase of Arctic Oscillation,Ural blocking,enhanced Siberian high,and eastward propagation of Rossby wave eventually induced the outbreak of an unprecedented cold wave in East Asia in early January 2021.
基金financially supported by the National High-tech Research and Development Program 863 (No.2009AA03Z518)
文摘The expanding curves of two kinds of 1000 MPa ultra-high strength cold rolled dual phase steels,which were C-Si-Mn-Cr and C-Si-Mn-Cr-Mo steel respectively,were detected on Gleeble-1500 thermal-mechanical simulator at different cooling rates.Combined with metallographic and hardness methods,the continuous cooling transformation curves (CCT) of the two steels were obtained.The results showed that Mo could raise the A r3 temperature,and strongly restrain the pearlite and bainite transformation.The reason for this was the interaction that the addition of Mo could increase the chemical driving force of ferrite transformation and the activation energy for the diffusion of carbon in austenite,which could decelerate the ferrite transformation.The hardness of the two steels was similar in the cooling rates range of this experiment and got higher with the increase of the cooling rates.When the cooling rates were above 7 ℃/s,the hardness almost kept constant because the most part of the microstructure was martensite.
文摘On the basis of NOAA/CPC data of sea surface temperature anomaly in the Nifio regions during Jan. 1950 - Dec. 2003, the wavelet power spectrum of SST were studied with significance and confidence testing at different scales in this paper. It shows that the SST are provided with multi-time scales structure nested one another, and vary on scales of 2 - 7 years, 8 - 20 years and 〉30 years. The most significant variation of the warm and cold episodes is in the 4-year band of period. The power, frequency structure and confidence of the same episode are different in different Nino regions. The intensity of oscillations is increasing at low frequency bands and decreasing at high frequency bands from east to west in the Nino regions, especially after 1970.
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.
基金National Natural Science Foundation of China(Grant No.51505240)Natural Science Foundation of Zhejiang(Grant No.LQ19E050004)+1 种基金Special Inventive Fund of Science and Technology in Shenyang(Grant No.Fl5-172-6-00)the State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals.Lanzhou University of Technology(Grant No.SKLAB02014001).
文摘Due to the improvement in fatigue strength of cold-rolled blades,the static recrystallization behavior of cold-rolled Inconel 718 alloy in the solid solution treatment was investigated with the methods of optical microscopy and electron backscattered diffraction.The effect ofδphase precipitation on the static recrystallization process was also analyzed.The results show thatδphase preferentially precipitates comparing to static recrystallization.Affecting by theδphase preferential precipitation process,sub-grain migration is the main nucleation mechanism in the static recrystallization of coldrolled Inconel 718 alloy at 980°C.Meanwhile,strain-induced boundary migration also exists as an aided nucleation mechanism when the rolling reduction is less than 30%.
基金Supported by the Strategy Program of Chinese Academy of Sciences(Nos.XDA10020104,XDA10020305)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.41421005)+2 种基金the National Natural Science Foundation of China(Nos.41476019,41606040)the NSFC-Shandong Joint Fund for Marine Science Research Centers(No.U1406401)the High Performance Computing Center,Institute of Oceanology,Chinese Academy of Sciences in Qingdao
文摘A winter onshore warm tongue extending from the Yellow Sea Warm Current to the southern Jiangsu coast, and an of fshore cold tongue extending from the southern Jiangsu coast to the southwest of Jeju Island(South Korea), are newly identified based on the sea-surface temperature from satellite remote sensing, and further confirmed by the distribution of suspended sediments. In addition, there are two obvious thermal fronts associated with the onshore warm tongue and off shore cold tongue. The narrow gap between the two thermal fronts is supposed to be the pathway for the off shore transport of cold coastal water and suspended sediments. The concurrence of onshore warm and of fshore cold tongues suggests the concurrence of onshore and off shore currents in the western Yellow Sea in winter, which seems to be inconsistent with the previously accepted view that, in winter, the Yellow Sea Coastal Current flows from the Old Huanghe Delta to the southwest of Jeju Island. This distinctive phenomenon helps establish an updated view of the circulation in the western Yellow Sea in winter.
文摘The purpose of this study was to investigate the effects of a traditional Japanese medicine Goshajinkigan (TJ-107) and Tokishigyakukagoshuyushokyoto (TJ-38) on warm sense threshold, cold sense threshold and the peripheral blood flow. 31 healthy volunteers (control group: 9people, TJ-107 group: 12 people, TJ-38group:10 people) were examined. Drugs administered 2.5 g a dose. Analysis was before and after 1 hour dosage. The warm and cold sense threshold in the thenar of the non-handedness site of these subjects was measured using a thermostimulator (Intercross-200, Intercross Co., Tokyo, Japan). The peripheral blood flow in the finger of the non-handedness site of these subjects was measured using a full-field laser perfusion imager (FLPI, Moor Instruments Ltd., England). Control: The vehicle had no significant effect on the warm sense threshold, cold sense threshold and the peripheral blood flow. TJ-107: The warm sense threshold and cold sense threshold were significantly decreased, and the reaction latency of cold sense was significantly shortening. The peripheral blood flow was significantly increased second and third finger at 115.6%, 119.3%, respectively. TJ-38: The cold sense threshold and the reaction latency of cold sense were significantly increased. The peripheral blood flow was significantly increased second and third finger with 114.3%, 112.8%, respectively. These results suggest that TJ-107 and TJ-38 have effects on the changed warm sense threshold, cold sense threshold and increased peripheral blood flow.
基金Project supported by the National Natural Science Foundation of China(51972181,61705231)Major Basic Research Projects of Shandong Natural Science Foundation(ZR2018ZB0650)+2 种基金China Postdoctoral Science Foundation(2015M580573)High Quality Course Construction Project of Graduate Education in Shandong Province(SDYKC18051)Postgraduate Tutor Ability Improvement Project of Shandong Province(SDYY17179)。
文摘A series of single phase,warm white light emitting phosphors,Gd(P_(x)V_(1−x))O_(4):y at%Sm^(3+),with 1 at%Bi^(3+) doping concentration were synthesized by high temperature solid state method in this work.The experimental results indicate broadband cyan emission of Bi^(3+)and characteristic orange-red emission of Sm^(3+)can be effectively tuned by changing the ratios of PO^(3−)_(4)/VO^(3−)_(4) in Gd(P_(x)V_(1−x))O_(4):1 at%Sm^(3+),1 at%Bi^(3+),and the energy transfer process among VO^(3−)_(4),Sm^(3+),Bi^(3+) also can be adjusted.Based on this,warm white light emitting can be realized by further optimizing the doping concentration of Sm^(3+) in the phosphors.At 423 K,the PL intensity of Gd(P_(0.7)V_(0.3))O_(4):2 at%Sm^(3+),1 at%Bi^(3+) remains~84.3%of the initial value at 293 K,while the measured quantum efficiency is 67.8%.EL spectrum analysis results of the fabricated white light emitting diode(wLED)based on a 310 nm UV-chip and Gd(P_(0.7)V_(0.3))O4:2 at%Sm^(3+),1 at%Bi^(3+)phosphors imply low correlated color temperature(3132 K)and appropriate color-rending index(R_(a)=82.7).These results demonstrate that Gd(P_(0.7)V_(0.3))O4:2 at%Sm^(3+),1 at%Bi^(3+)is a good candidate for manufacturing UV-activated warm white light emitting diodes.
文摘Influence of severe cold deformation of titanium alloy Ti-1.5%A1-6.8%Mo-4.5%Fe in metastable β condition on the evolution of phase composition, microstructure, and tensile properties during continuous rapid heating was studied. As-deformed alloy was characterized by quasi-amorphous single-phase β condition with an abnormal temperature dependence of electric resistance that was normalized after 48 h exposure at room temperature as a result of isothermal ω phase precipitation. Subsequent rapid heating with a rate of 5 ℃/s caused recovery and recrystallization. Tensile properties of the alloy after different treatments were determined and discussed.
基金supported by the project of Korea Polar Research Institute (Grant no. PE18130)
文摘The rate of warming of Arctic surface temperature is about 2–3 times faster than the global mean surface warming. Increases of ice albedo feedback and water vapor as well as moisture intrusion from outside the Arctic all have major roles in this phenomenon. In contrast to this rapid Arctic warming, in recent decades, stronger cold air outbreaks have occurred more frequently during winter in East Asia than were recorded in the 1990s, resulting in severe socioeconomic impacts. A number of related studies have claimed the increased frequency of these stronger cold air outbreaks is linked to the amplified warming in the Arctic through complicated mechanisms. As there are time lags between the observed Arctic warming and East Asian cold weather response at various scales, understanding the entire chain of processes from the Arctic to East Asia has importance for forecasting winter weather in East Asia. There are two pathways linking Arctic warming with East Asian cold weather events. One is the synoptic-scale pathway in the lower troposphere via strengthening of the Siberian High initiated by Ural blocking. The other is the planetary-scale path through the stratosphere via activation of planetary waves and downward propagation, which weakens the polar vortex. This study briefly reviews the current understanding of the linkage mechanisms between Arctic warming and East Asian winter cold weather.
基金This study was jointly supported by the National Key R&D Program(Grant No.2018YFC1505904)the National Natural Science Foundation of China(Grant Nos.41830969 and 41705052)the Basic Scientific Research and Operation Foundation of CAMS(Grant No.2018Z006).
文摘Under recent Arctic warming,boreal winters have witnessed severe cold surges over both Eurasia and North America,bringing about serious social and economic impacts.Here,we investigated the changes in daily surface air temperature(SAT)variability during the rapid Arctic warming period of 1988/89–2015/16,and found the daily SAT variance,mainly contributed by the sub-seasonal component,shows an increasing and decreasing trend over eastern Eurasia and North America,respectively.Increasing cold extremes(defined as days with daily SAT anomalies below 1.5 standard deviations)dominated the increase of the daily SAT variability over eastern Eurasia,while decreasing cold extremes dominated the decrease of the daily SAT variability over North America.The circulation regime of cold extremes over eastern Eurasia(North America)is characterized by an enhanced high-pressure ridge over the Urals(Alaska)and surface Siberian(Canadian)high.The data analyses and model simulations show the recent strengthening of the high-pressure ridge over the Urals was associated with warming of the Barents–Kara seas in the Arctic region,while the high-pressure ridge over Alaska was influenced by the offset effect of Arctic warming over the East Siberian–Chukchi seas and the Pacific decadal oscillation(PDO)–like sea surface temperature(SST)anomalies over the North Pacific.The transition of the PDO-like SST anomalies from a positive to negative phase cancelled the impact of Arctic warming,reduced the occurrence of extreme cold days,and possibly resulted in the decreasing trend of daily SAT variability in North America.The multi-ensemble simulations of climate models confirmed the regional Arctic warming as the driver of the increasing SAT variance over eastern Eurasia and North America and the overwhelming effect of SST forcing on the decreasing SAT variance over North America.Therefore,the regional response of winter cold extremes at midlatitudes to the Arctic warming could be different due to the distinct impact of decadal SST anomalies.
基金The authors are grateful to the Province Natural Science Foundation of Zhejiang(Grant No.LQ19E050004)for financial support.The authors also graciously thank China Airlines Shenyang Liming Aeroengine Co.,Ltd.for aiding in providing the experimental Inconel 718 alloys.
文摘Due to the important role ofδphase's quantity and morphology in the mechanical and fatigue properties of Inconel 718 alloy and its components,it is necessary to renew insights into the effect of cold deformation on theδphase precipitation,especially on the morphology evolution.Therefore,the nucleation and growth behavior ofδphase in cold-rolled Inconel 718 alloy during aging were investigated.The results show that the precipitation rate and volume fraction ofδphase increase with increasing the cold rolling reduction from 10%to 50%.The volume fraction ofδphase reaches equilibrium after 5 h,remaining at 5.98%,6.52%,and 6.79%under different rolling reductions(10%,30%,and 50%),respectively.The nucleation ofδphase mainly occurs on different sites(grain boundaries,new twin boundaries and old twin boundaries)under 10%rolling reduction,whileδphase mainly nucleates on the new grain boundaries of static recrystallization due to 50%rolling reduction.And the growth ofδphase undergoes a process of alternate orientation growth from spherical(nucleation)→short rod(longitudinal orientation growth)→short rod(radial orientation growth)→dynamic equilib-rium.Under 10%rolling reduction,δphase tends to grow into the matrix,while under 50%rolling reduction,the orientation grows faster and is easily affected by the grain boundary curvature.
基金the Natural Science Foundation of the Department of Education, Guangdong Province, China (No. 02025).
文摘A new method for analysis of trace mercury in water samples was developed, based on the combination of preconcentration/separation using dithizone-modified nanometer titanium dioxide （TiO2） as a solid phase extractant and determination by cold vapor atomic adsorption spectrometry （CVAAS）. Dithizone was dissolved with alcohol and loaded on the surface of nano-sized TiO2 powders by stirring. The static adsorption behavior of Hg^2＋on the dithizone-modified nanoparficles was investigated in detail. It was found that excellent adsorption ratio for Hg^2＋ could be obtained in the pH range of 7-8 with an oscillation time of 15 rain, and a 5 mL of 3.5 mol·L^-1 HCI solution could quantitatively elute Hg^2＋ from nanometer TiO2 powder. Common coexisting ions caused no obvious influence on the determination of mercury. The mechanisms for the adsorption and desorption were discussed. The detection limit （30） for Hg^2＋ was calculated to be 5 ng·L^-1. The proposed method was applied to the determination of Hg^2＋ in a mineral water sample and a Zhujiang River water sample. By the standard addition method, the average recoveries were found to be 94.4%-108.3% with RSD （n = 5） of 2.9%-3.5%.
