Short communication:Extreme glacier mass loss triggered by high temperature and drought during hydrological year 2022/2023 in Qilian Mountains

In the hydrological year 2022/2023,the glaciers in the Qilian Mountains experienced unprecedented mass loss.The glacier-wide mass balance was-1,188 mm w.e.,in contrast to-350 mm of average mass balance since 1990 over the Bailanghe Glacier No.12 in the middle of Qilian Mountains.The temperature during 2022–2023 reached the highest value ever recorded,second only to 2022,while at the same time the precipitation amount was less compared to other year since 2000,which together led to the strongest glacier mass loss during 2022–2023.The atmospheric circulation analysis shows that the high temperature in the Qilian Mountains in 2023 was jointly caused by the Arctic air mass and East Asian monsoon.

Temporal and Spatial Variation of Summer Extreme High Temperature in Guizhou Province from 1970 to 2020

Based on the daily maximum temperature data of 31 meteorological observation stations and some statistical methods, the temporal and spatial characteristics of summer extreme high temperature in Guizhou province from 1970 to 2020 are analyzed. The results indicate that: 1) The threshold of extreme high temperature (EHT) in summer in Guizhou province had a large spatial difference, with decreasing characteristics from the northeast to the southwest, it was negatively correlated with the altitude. 2) In most parts of Guizhou province, the extreme high temperature days (EHTD) in summer can reach about 4.2 d, the lowest EHTD occurred in the southernmost part. From June to August, the EHTD gradually increased, especially in Central and eastern parts of Guizhou province. However, the extreme high temperature intensity (EHTI) displayed similar distribution characteristics in summer, June, July and August, with larger value in the northeast part and lower value in the southwest part of Guizhou. 3) EHTD had a rising trend in almost stations, except for the PZ station, the increased range and intensity gradually increased from June to August. But the EHTI had a larger spatial difference, especially in June, it declined in most parts of Guizhou, the declined scope and intensity gradually decreased in July, and completely increased in August, this made EHTI show an increasing trend in summer in most parts the Guizhou province. 4) The averaged EHTD increased by 0.62 d/10a (p 0.1), the significant increase also occurred in August, but it increased insignificantly in June and July. The averaged EHTI had insignificant increase in summer and the three months. In general, the EHTD and EHTI increased in most parts of Guizhou province during the period of 1970-2020, this may be related to the changes of them in August.

Highly efficient H-bonding charge-transfer complex for microsupercapacitors under extreme conditions of low temperatures

Owing to sluggish ionic mobility at low temperatures, supercapacitors, as well as other energy-storage devices, always suffer from severe capacity decay and even failure under extreme low-temperature circumstances. Solar-thermal-enabled self-heating promises an attractive approach to overcome this issue.Here, we report a unique H-bonding charge-transfer complex with a high photothermal conversion efficiency of 79.5% at 405 nm based on chloranilic acid and albendazole. Integrated with a microsupercapacitor, the chloranilic acid-albendazole complex(CAC) film prompts an apparent temperature increase of 22.7 °C under 1 sun illumination at-32.6 °C, effectively elevating the working temperature of devices.As a result, the rate capability of the microsupercapacitor has been significantly improved with a 17-fold increase in capacitance at a current density of 60 μA cm^(-2), leading to outstanding low-temperature performances. Importantly, the integrated device is capable of working at a low temperature of-30 °C in the open air, which demonstrates the potential of CAC in practical applications for low-temperature ultracapacitive energy-storage devices.

Analysis on the Climatic Characteristics of High and Low Temperature in the East of Hexi Corridor in Recent 50 Years

[Objective] The research aimed to provide the certain theory basis for the accurate forecast and early warning of high and low temperature in the east of Hexi Corridor.[Method] Based on the high(the daily highest temperature ≥35 ℃) and low(the daily lowest temperature ≤-20 ℃) temperature data in five observatories in the east of Hexi Corridor during 1960-2009,the temporal and spatial distribution,intensity,continuity and circulation situation of high and low temperature were analyzed in detail by using the statistical method.[Result] The high temperature weather in the east of Hexi Corridor mainly happened in the edge of northeast desert,and the low temperature mainly happened in the mountain zone where the altitude was higher and the edge of north desert.As the climate became warm,the high temperature days showed the weak increase trend,and the intensity strengthened.The low temperature days showed the obvious decrease trend,and the intensity weakened.The high temperature weather mainly occurred in June,August,and the low temperature mainly occurred in January,February,December.The high and low temperature weather had the durative characteristic.The strong high and low temperature mainly occurred in the durative time of high and low temperature.The high temperature weather appeared in the zone where was controlled and affected by the subtropical high.The low temperature weather appeared in the zone where the strong cold air accumulated and invaded.[Conclusion] The research had the extremely important significance on servicing for the agriculture,preventing and reducing the natural disasters,promoting the local economic development.

An Abrupt Increase in the Summer High Temperature Extreme Days across China in the mid-1990s

Based on the daily maximum surface air temperature records from an updated homogenized temperature dataset for 549 Chinese stations during 1960-2008,we reveal that there is an abrupt increase in the number of days with high temperature extremes （HTEs,an HTE day is defined when the maximum temperature exceeds the 95th percentile of the daily maximum temperature distributions） across China in the mid-1990s.Before this regime shift,the average number of HTE days is about 2.9 d yr 1 during the period from the 1970s to the early 1990s,while it rocketed to about 7.2 d yr 1 after the mid-1990s.We show that the significant HTE day increase occurs uniformly across the whole of China after the regime shift.The observational evidence raises the possibility that this change in HTE days is associated with global-scale warming as well as circulation adjustment.Possible causes for the abrupt change in the HTE days are discussed,and the circulation adjustment is suggested to play a crucial role in the increase in HTE days in this region.

The Impact of Indian Ocean Variability on High Temperature Extremes across the Southern Yangtze River Valley in Late Summer

In this study, the teleconnection between Indian Ocean sea surface temperature anomalies （SSTAs） and the frequency of high temperature extremes （HTEs） across the southern Yangtze River valley （YRV） was investigated. The results indicate that the frequency of HTEs across the southern YRV in August is remotely influenced by the Indian Ocean basin mode （IOBM） SSTAs. Corresponding to June-July-August （JJA） IOBM warming condition, the number of HTEs was above normal, and corresponding to IOBM cooling conditions, the number of HTEs was below normal across the southern YRV in August. The results of this study indicate that the tropical IOBM warming triggered low-level anomalous anticyclonic circulation in the subtropical northwestern Pacific Ocean and southern China by emanating a warm Kelvin wave in August. In the southern YRV, the reduced rainfall and downward vertical motion associated with the anomalous low-level anticyclonic circulation led to the increase of HTE frequency in August.

Effect of microstructure on the low temperature toughness of high strength pipeline steels

Microstructure observations and drop-weight tear test were performed to study the microstructures and mechanical properties of two kinds of industrial X70 and two kinds of industrial X80 grade pipeline steels. The effective grain size and the fraction of high angle grain boundaries in the pipeline steels were investigated by electron backscatter diffraction analysis. It is found that the low temperature toughness of the pipeline steels depends not only on the effective grain size, but also on other microstructural factors such as martensite-austenite （MA） constituents and precipitates. The morphology and size of MA constituents significantly affect the mechanical properties of the pipeline steels. Nubby MA constituents with large size have significant negative effects on the toughness, while smaller granular MA constituents have less harmful effects. Similarly, larger Ti-rich nitrides with sharp corners have a strongly negative effect on the toughness, while fine, spherical Nb-rich carbides have a less deleterious effect. The low temperature toughness of the steels is independent of the fraction of high angle grain boundaries.

Microstructure of Surface Layer Formed at Low Temperature and High Carbon Concentration Carburizing with Rare Earth Element

A suitable carburized microstructure with fine granular dispersed carbides in hypereutectoid zone,ultra fine martensite in matrix and recrystallized austenite to be refined to the grain size of 12～14 has been obtained by a new process,which is a high carbon concentration carburizing with rare earth element at low temperature(860～880℃)in a discontinuous gas carburization furnace.There was not much difference for the microstructure in eutectic zone between this and conventional process.Forming mechanism of granular carbides has been also studied in this paper.

Future Changes in Extreme High Temperature over China at 1.5℃-5℃ Global Warming Based on CMIP6 Simulations

Extreme high temperature(EHT)events are among the most impact-related consequences related to climate change,especially for China,a nation with a large population that is vulnerable to the climate warming.Based on the latest Coupled Model Intercomparison Project Phase 6(CMIP6),this study assesses future EHT changes across China at five specific global warming thresholds(1.5℃-5℃).The results indicate that global mean temperature will increase by 1.5℃/2℃ before 2030/2050 relative to pre-industrial levels(1861-1900)under three future scenarios(SSP1-2.6,SSP2-4.5,and SSP5-8.5),and warming will occur faster under SSP5-8.5 compared to SSP1-2.6 and SSP2-4.5.Under SSP5-8.5,global warming will eventually exceed 5℃ by 2100,while under SSP1-2.6,it will stabilize around 2℃ after 2050.In China,most of the areas where warming exceeds global average levels will be located in Tibet and northern China(Northwest China,North China and Northeast China),covering 50%-70%of the country.Furthermore,about 0.19-0.44 billion people(accounting for 16%-41%of the national population)will experience warming above the global average.Compared to present-day(1995-2014),the warmest day(TXx)will increase most notably in northern China,while the number of warm days(TX90p)and warm spell duration indicator(WSDI)will increase most profoundly in southern China.For example,relative to the present-day,TXx will increase by 1℃-5℃ in northern China,and TX90p(WSDI)will increase by 25-150(10-80)days in southern China at 1.5℃-5℃ global warming.Compared to 2℃-5℃,limiting global warming to 1.5℃ will help avoid about 36%-87%of the EHT increases in China.

ISOCHRONOUS STRESS-STRAIN CURVES OF LOW ALLOY STEEL CROSS-WELD-SPECIMEN AT HIGH TEMPERATURE

In this work, a parametric approach is presented and utilized to determine the creep properties of weldments; then the model of creep strain for cross weld specimen is given. On the basis of the experimental results, attempt has been made to establish equations of the isochronous stress-strain for weld joint that can predict the function of loading and service time in use of the creep data of base metal and weld metal.

An effective'salt in dimethyl sulfoxide/water'electrolyte enables high-voltage supercapacitor operated at-50℃

Compared with organic electrolytes,aqueous electrolytes exhibit significantly higher ionic conductivity and possess inherent safety features,showcasing unique advantages in supercapacitors.However,challenges remain for low-salt aqueous electrolytes operating at high voltage and low temperature.Herein,we report a low-salt(0.87 m,m means mol kg^(-1))'salt in dimethyl sulfoxide/water'hybrid electrolyte with non-flammability via hybridizing aqueous electrolyte with an organic co-solvent of dimethyl sulfoxide(hydrogen bond acceptor).As a result,the 0.87 m hybrid electrolyte exhibits enhanced electrochemical stability,a freezing temperature below-50℃,and an outstanding ionic conductivity of 0.52mS cm~(-1)at-50℃.Dimethyl sulfoxide can anchor water molecules through intermolecular hydrogen bond interaction,effectively reinforcing the stability of water in the hybrid electrolyte.Furthermore,the interaction between dimethyl sulfoxide and water molecules diminishes the involvement of water in the generation of ordered ice crystals,finally facilitating the low-temperature performance of the hybrid electrolyte.When paired with the 0.87 m'salt in dimethyl sulfoxide/water'hybrid electrolyte,the symmetric supercapacitor presents a 2.0 V high operating voltage at 25℃,and can operate stably at-50℃.Importantly,the suppressed electrochemical reaction of water at-50℃further leads to the symmetric supercapacitor operated at a higher voltage of 2.6 V.This modification strategy opens an effective avenue to develop low-salt electrolytes for high-voltage and low-temperature aqueous supercapacitors.

Climatology and Trends of High Temperature Extremes across China in Summer

Based on the daily maximum air temperature data from 300 stations in China from 1958 to 2008, the climatological distribution of the number of days with high temperature extremes （HTEs, maximum temperatures higher than 35℃） are studied with a focus on the long-term trends. Although the number of HTE days display well-defined sandwich spatial structures with significant decreasing trends in central China and increasing trends in northern China and southern China, the authors show that the decrease of HTE days in central China occurs mainly in the early period before the 1980s, and a significant increase of HTE days dominates most of the stations after the 1980s. The authors also reveal that there is a jump-like acceleration in the number of HTE days at most stations across China since the mid 1990s, especially in South China, East China, North China, and northwest China.

Trends in extreme high temperature at different altitudes of Southwest China during 1961–2014

This study analyzed the trends in extreme high temperature in Southwest China based on the observed daily maximum temperature and average temperature data from 410 Chinese stations recently released by the China Meteorological Administration.The authors found that the trends in extreme high temperature at different altitudes of Southwest China exhibit staged variations during a recent 50-year period(1961–2014).The trends in mean temperature and maximum temperature also exhibit phase variation.All temperature-related variables increase gently during the period 1975–94,whereas they increase dramatically during the recent period of 1995–2014,with a rate that is approximately two to ten times more than that during 1975–94.In addition,the trends in mean temperature,maximum temperature,and the frequency of extreme high temperature in the low altitudes transit from negative to positive in the two periods,while they increase dramatically in the mid-and high-altitude areas during 1995–2014,the well-known global warming hiatus period.In particular,the maximum temperature increases much faster than that of average temperature.This result implies that the regional temperature trend could be apparently different from the global mean temperature change.

Comparative Analysis of Extreme High Temperature Weather in the Summers of 2013 and 2003

The characteristics of regional high temperature(HT) weather in 2013 and 2003 and their causes were studied using daily maximum temperature data, National Center for Environmental Prediction(NCEP) reanalysis data, and outgoing longwave radiation(OLR) data. For these two years of HT weather, there were many similar characteristics, such as their long duration, wide range, high intensity, and severe influence. However, there were also three obvious differences: firstly, in 2013, the major area where HT weather occurred was farther north than in 2003; secondly, the HT weather in South China and the southeast area of Jiangnan in 2013 lasted fewer days than in 2003, but in other areas it lasted for more days than in 2003; thirdly, the intensity of the HT weather in 2013 was also stronger in the north and weaker in the south, similar to that of the duration. A strong and stable western Pacific subtropical high(WPSH), a continental warm high, and the distribution of the warm center in the lower troposphere played important roles in the HT weather formation. Several probable causes for the differences are that the cold air was weaker, the WPSH was farther north, and the tropical convective systems were stronger in 2013 than in 2003. Finally, a preliminary cause analysis of the WPSH anomaly was presented.

Piezoelectric properties of low loss and high Curie temperature (Bi, La)FeO_3-Pb(Ti, Mn)O_3 ceramics with Mn doping

Piezoelectric ceramics of 0.6(Bi0.9La0.1)FeO3-0.4Pb(Ti1-xMnx)O3 (BLF-PTM) for x=0, 0.01, 0.02, and 0.03 were prepared by sol-gel process combined with a solid-state reaction method. The tan? for BLF-PTM of x=0.01 is just 0.006 at 1 kHz, drastically decreasing by using Mn dopants. The TC increases to 490 ℃ for BLF-PTM of x=0.02. Furthermore, Mn modification effectively enhances the poling state and the piezoelectric properties of BLF-PTM. The kp, Qm, d33, and g33 of 0.34, 403, and 124 pC1·N-1 and 37×10-3 Vm·N-1 are achieved for BLF-PTM of x=0.01. The results indicate that Mn modified BLF-PTM is a competitive high power and high temperature piezoelectric material with excellent piezoelectric properties.

Thin Film Chip Resistors with High Resistance and Low Temperature Coefficient of Resistance

High resistance thin film chip resistors(0603 type) were studied,and the specifications are as follows:1 k? with tolerance about ±0.1% after laser trimming and temperature coefficient of resistance(TCR) less than ±15×10-6/℃.Cr-Si-Ta-Al films were prepared with Ar flow rate and sputtering power fixed at 20 standard-state cubic centimeter per minute(sccm) and 100 W,respectively.The experiment shows that the electrical properties of Cr-SiTa-Al deposition films can meet the specification requirements of 0603 ty...

Lithium-Sulfur Batteries at Extreme Temperatures:Challenges,Strategies and Prospects

High-energy-density-batteries working at a wide-temperature range are urgently required in many performance-critical areas.Lithium-sulfur batteries(LSB)are promising high-energy-density batteries that have the potential to maintain high performance at extreme temperatures.However,some problems like severe shuttling and safety issues at high temperatures or sluggish reaction kinetics and charge-transfer process at low temperatures decrease the performance and hinder their practical uses in extreme temperature conditions.Therefore,broadening the working temperature of LSB with stable electrochemical performance becomes a crucial topic.In this paper,the key stumbling blocks for high and low-temperature LSB are comprehensively discussed.The solutions from the aspects of electrolyte and electrode materials are discussed to solve the aggravating shuttle effect and thermal safety issues under high temperature and the sluggish reaction kinetics under low temperature.Moreover,some specific promising solutions to extend the operating temperature range of LSB are also proposed and highlighted,which provide potential research directions on the practical LSB application in future.

Low-temperature and high-voltage planar micro-supercapacitors based on anti-freezing hybrid gel electrolyte

Micro-supercapacitors(MSCs)are considered as highly competitive power sources for miniaturized electronics.However,narrow voltage window and poor anti-freezing properties of MSCs in conventional aqueous electrolytes lead to low energy density and limited environmental adaption.Herein,we report the construction of low-temperature and high-energy-density MSCs based on anti-freezing hybrid gel electrolytes(HGE)through introducing ethylene glycol(EG)additives into aqueous LiCl electrolyte.Since EG partially destroys hydrogen bond network among water molecules,the HGE exhibits maximum electrochemical stability window of 2.7 V and superior anti-freezing features with a glass transition temperature of-62.8℃.Further,the optimized MSCs using activated carbon microelectrodes possess impressive volumetric capacitance of 28.9 F cm^(-3)and energy density of 10.3 mWh cm^(-3)in the voltage of 1.6 V,2.6 times higher than MSCs tested in 1.2 V.Importantly,the MSCs display 68.3%capacitance retention even at-30℃ compared to the value at 25℃,and ultra-long cyclability with 85.7%of initial capacitance after 15,000 times,indicating extraordinary low-temperature performance.Besides,our devices offer favorable flexibility and modular integration.Therefore,this work provides a general strategy of realizing flexible,safe and anti-freezing microscale power sources,holding great potential towards subzero-temperature microelectronic applications.

Distribution Characteristics of Winter Continuous Extreme Low Temperature in China

[Objective] The research aimed to study the distribution characteristics of winter continuous extreme low temperature in China. [Method] Based on the daily minimum temperature data in winter during 1961-2008 in 195 observatories, the continuous extreme low temperature event (cold night) which happened in winter in China and the distribution characteristics of accumulated temperature anomaly in 48 years were analyzed by using the actual probability distribution threshold method. [Result] Besides in Northeast China, Northwest China and Qinghai-Tibet Plateau where the geographical position was northerly, and the altitude was high, the long-time (above 5 d) extreme low temperature event was also easy to happen in the south of Yangtze River, especially in Guizhou, Guangxi, Hunan and so on. The continuous extreme low temperature event in the middle and lower reaches of Yellow River was the least. Started from the metaphase of the 1980s, the frequency trend of continuous extreme low temperature event decreased. But in 1992, 2000 and 2007, the low temperature event which continued above 7 d was more than the average. The accumulated cold in January in 48 years was the strongest. The second one was in February, and the smallest was in December. The accumulated cold in Northeast China and the north of Inner Mongolia was the biggest in December and January. The accumulated cold in the north of Xinjiang was the biggest in February. In the whole winter, the accumulated cold in Qinghai-Tibet Plateau was the smallest. The chilling injury was easier to happen in Guizhou, Guangxi and Hunan than other south areas in December and February. The occurrence probability of chilling injury in most areas of Szechwan Basin, Yunnan and Qinling Mountains in central China was smaller than that in other areas. [Conclusion] The research provided the reference basis for analyzing the influence of chilling injury on the agriculture in China.

Intra-seasonal Features of an Extreme High Temperature Event in 2011 in Eastern China and Its Atmospheric Circulation

Based on the daily maximum air temperature(T_(max))data from the China Meteorological Data Network and the NCEP/DOE reanalysis data,the intra-seasonal circulation and evolution of an extreme high temperature event(EHTE)in the middle reaches of the Yangtze River(MYR)from August 9-21,2011 were explored,as well as the influence of diabatic heating on the position variation of the Western Pacific subtropical high(WPSH).Results show that the daily T_(max) in the MYR exhibits a vigorous intraseasonal oscillation(ISO)of 10-25 days in the extended summer of 1980-2018.The main factors affecting the EHTE in the summer of 2011 are the low-frequency wave train propagating southeastward in the mid-latitude of the upper troposphere and the low-frequency anticyclone moving northwestward in the lowlatitude of the mid-lower troposphere.The diagnosis of 925hPa thermodynamic equation indicates that the ISO features of the T_(max) in the core region is determined by the intra-seasonal variation of the adiabatic variation.In addition,the variations of the WPSH correspond well to the distribution of apparent heat source.In the early stage of the high temperature process,the apparent heat source in the north of the Bay of Bengal is a certain indicator for the westward extension of the WPSH.