The ever-increasing demands for modern energy storage applications drive the search for novel anode materials of lithium(Li)-ion batteries(LIBs) with high storage capacity and long cycle life, to outperform the conven...The ever-increasing demands for modern energy storage applications drive the search for novel anode materials of lithium(Li)-ion batteries(LIBs) with high storage capacity and long cycle life, to outperform the conventional LIBs anode materials. Hence, we report amorphous ternary phosphorus chalcogenide(aP_(4)SSe_(2)) as an anode material with high performance for LIBs. Synthesized via the mechanochemistry method, the a-P_(4)SSe_(2) compound is endowed with amorphous feature and offers excellent cycling stability(over 1500 mA h g^(-1) capacity after 425 cycles at 0.3 A g^(-1)), owing to the advantages of isotropic nature and synergistic effect of multielement forming Li-ion conductors during battery operation. Furthermore,as confirmed by ex situ X-ray diffraction(XRD) and transmission electron microscope(TEM), the a-P_(4)SSe_(2)anode material has a reversible and multistage Li-storage mechanism, which is extremely beneficial to long cycle life for batteries. Moreover, the autogenous intermediate electrochemical products with fast ionic conductivity can facilitate Li-ion diffusion effectively. Thus, the a-P_(4)SSe_(2)electrode delivers excellent rate capability(730 mA h g^(-1)capacity at 3 A g^(-1)). Through in situ electrochemical impedance spectra(EIS) measurements, it can be revealed that the resistances of charge transfer(R_(SEI)) and solid electrolyte interphase(R_(Ct)) decrease along with the formation of Li-ion conductors whilst the ohmic resistance(R_(Ω)) remains unchanged during the whole electrochemical process, thus resulting in rapid reaction kinetics and stable electrode to obtain excellent rate performance and cycling ability for LIBs. Moreover, the formation mechanism and electrochemical superiority of the a-P_(4)SSe_(2)phase, and its expansion to P_(4)S_(3-x)Se_(x)(x = 0, 1, 2, 3) family can prove its significance for LIBs.展开更多
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 th...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.展开更多
Stationary long pulse plasma of high electron temperature was produced on EAST for the first time through an integrated control of plasma shape, divertor heat flux, particle exhaust, wall conditioning, impurity manage...Stationary long pulse plasma of high electron temperature was produced on EAST for the first time through an integrated control of plasma shape, divertor heat flux, particle exhaust, wall conditioning, impurity management, and the coupling of multiple heating and current drive power. A discharge with a lower single null divertor configuration was maintained for 103 s at a plasma current of 0.4 MA, q95 ≈7.0, a peak electron temperature of 〉4.5 keV, and a central density ne（0）-2.5×10^19 m^-3. The plasma current was nearly non-inductive （Vloop 〈0.05 V, poloidal beta - 0.9） driven by a combination of 0.6 MW lower hybrid wave at 2.45 GHz, 1.4 MW lower hybrid wave at 4.6 GHz, 0.5 MW electron cyclotron heating at 140 GHz, and 0.4 MW modulated neutral deuterium beam injected at 60 kV. This progress demonstrated strong synergy of electron cyclotron and lower hybrid electron heating, current drive, and energy confinement of stationary plasma on EAST. It further introduced an example of integrated ＂hybrid＂ operating scenario of interest to ITER and CFETR.展开更多
We have observed that berberine prolonged life span and improved viability of pupae and climbing activity of imagoes of wild-type Drosophila melanogaster maintained at 23°C. As a continuation of our studies of be...We have observed that berberine prolonged life span and improved viability of pupae and climbing activity of imagoes of wild-type Drosophila melanogaster maintained at 23°C. As a continuation of our studies of berberine effect on life span, we were interested to evaluate the effect of berberine of life span in flies maintained at a higher temperature (28°C) known to accelerate aging in wild type flies. Considering that genetically or pharmacologically induced deficiency of TRP conversion into KYN prolonged life span in a Drosophila model, we compared the effects of berberine, a powerful inhibitor of kynurenine (KYN) formation from tryptophan (TRP), on life span in wild type and in Drosophila melanogaster mutants (vermilion) with deficient TRP-KYN metabolism maintained at 23°C and 28°C. High (28°C) ambient temperature decreased life span in both wild type and vermilion flies. Aging accelerating effect of high temperature was more pronounced in Oregon than in vermilion flies (-60% vs. -40% decrease of mean life span, resp). Berberine attenuated the aging-accelerating effect of high temperature. Effect of berberine was more pronounced in Oregon (+46%) than in vermilion (+22%) flies. The obtained data suggested the possible involvement of TRP-KYN metabolism in the aging-acceleration effect of the high temperature and in protective effect of berberine.展开更多
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 wit...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.展开更多
Development of gas turbine oils that can be used in higher temperature conditions remains the greatest technological challenge. Though the maximum operating temperature of conventional lubricating oils is generally se...Development of gas turbine oils that can be used in higher temperature conditions remains the greatest technological challenge. Though the maximum operating temperature of conventional lubricating oils is generally set around 100 ℃, or 140 ℃ for scavenged oils, it is predicted that the future will require oils to function at 200 ℃ or above. To find a clue to developing oils that can be used at higher temperatures, this study attempted to estimate service lives and operating temperature ranges of certain oils, including oils conforming to MIL-PRF-23699, which are deemed promising candidates for high-temperature applications, by analyzing their reaction rates of degradation and degeneration by oxidation. Among a number of methods used in the analyses of reaction rates, this study chose thermo-gravimetry （TG）, with which estimations can be made relatively easily.展开更多
Distributed temperature sensing is known to provide sharp signals which are very efficient for mapping hydraulically active fractures in wellbores. High-resolution temperature sensing has specifically demonstrated its...Distributed temperature sensing is known to provide sharp signals which are very efficient for mapping hydraulically active fractures in wellbores. High-resolution temperature sensing has specifically demonstrated its capacity to characterize very low flows in wellbores. But as sharp as they can be, temperature profiles are often difficult to decipher. The aim of the present work is to provide and to test the “Borehole Heat Budget Calculator” (BHB Calculator), which is implemented as a fast and easy to use tool for the quantitative analysis of depth-temperature profiles. The Calculator is suitable for most pumping and draining configurations, as the heat budget is generalized for modelling multidirectional flow systems within the same wellbore. The formatted worksheet allows the quick exploitation of temperature logs, and is applicable for the characterization of distributed fractures in long screened wellbores. Objectives of the heat modelling are to enhance the readability of complex depth-temperature data, as well as to quantify distribution of inflow intensities and temperatures with depth. The use of heat budget helps to clearly visualize how heat conduction and heat advection contributions are distributed along wellbores profiles. Calculations of inflow temperatures and their evolution through pumping duration is a prerequisite to infer about the nature of aquifer properties (i.e. conduits, distributed or discrete fractures, porous media), as well as to give insight information about the mapping of effective flow paths draining the aquifer. The efficiency and limitations of the BHB Calculator are being tested through high-resolution temperature logging, along with complementary flowmetering and televiewing logging in fractured aquifers located in the St-Lawrence Lowlands, Quebec, Canada.展开更多
超高温灭菌(ultra-high temperature treated,UHT)乳是一类长期储存的液态乳品,其货架期长短直接影响着产品的市场竞争力和消费者满意度。UHT乳的货架期常常受到多种因素的影响,包括但不限于:即使经过UHT却仍在乳中残留的部分生物因子...超高温灭菌(ultra-high temperature treated,UHT)乳是一类长期储存的液态乳品,其货架期长短直接影响着产品的市场竞争力和消费者满意度。UHT乳的货架期常常受到多种因素的影响,包括但不限于:即使经过UHT却仍在乳中残留的部分生物因子、货架期预测模型的合理性与准确性等。这些因素往往导致成品UHT乳在其储存货架期内发生如凝胶老化、脂肪上浮、风味改变、颜色改变等品质劣变现象。本文以近年来国内外对于影响UHT乳货架期稳定性的因素着手,分别解释了耐热芽孢、蛋白酶及脂肪酶影响UHT乳货架期寿命的机制,阐述了其引起的UHT乳货架期内的品质劣变现象;总结介绍了Arrhenius方程、多因素回归方程和BP神经网络3种货架期预测模型,在分别分析其运用环境的同时,对其优劣点进行了对比;最后在UHT乳的收奶端及生产端对延长UHT乳货架期的辅助技术进行了综述,以期从影响UHT乳货架期的相关因素入手,为今后UHT乳的生产及相关研究提供参考。展开更多
基金supported by the Regional Innovation and Development Joint Fundthe National Natural Science Foundation of China (Grant No. U20A20249)+1 种基金the Science and Technology Program of Guangdong Province of China (Grant No.2019A050510012, 2020A050515007, 2020A0505090001)the Guangzhou emerging industry development fund project of Guangzhou development and reform commission。
文摘The ever-increasing demands for modern energy storage applications drive the search for novel anode materials of lithium(Li)-ion batteries(LIBs) with high storage capacity and long cycle life, to outperform the conventional LIBs anode materials. Hence, we report amorphous ternary phosphorus chalcogenide(aP_(4)SSe_(2)) as an anode material with high performance for LIBs. Synthesized via the mechanochemistry method, the a-P_(4)SSe_(2) compound is endowed with amorphous feature and offers excellent cycling stability(over 1500 mA h g^(-1) capacity after 425 cycles at 0.3 A g^(-1)), owing to the advantages of isotropic nature and synergistic effect of multielement forming Li-ion conductors during battery operation. Furthermore,as confirmed by ex situ X-ray diffraction(XRD) and transmission electron microscope(TEM), the a-P_(4)SSe_(2)anode material has a reversible and multistage Li-storage mechanism, which is extremely beneficial to long cycle life for batteries. Moreover, the autogenous intermediate electrochemical products with fast ionic conductivity can facilitate Li-ion diffusion effectively. Thus, the a-P_(4)SSe_(2)electrode delivers excellent rate capability(730 mA h g^(-1)capacity at 3 A g^(-1)). Through in situ electrochemical impedance spectra(EIS) measurements, it can be revealed that the resistances of charge transfer(R_(SEI)) and solid electrolyte interphase(R_(Ct)) decrease along with the formation of Li-ion conductors whilst the ohmic resistance(R_(Ω)) remains unchanged during the whole electrochemical process, thus resulting in rapid reaction kinetics and stable electrode to obtain excellent rate performance and cycling ability for LIBs. Moreover, the formation mechanism and electrochemical superiority of the a-P_(4)SSe_(2)phase, and its expansion to P_(4)S_(3-x)Se_(x)(x = 0, 1, 2, 3) family can prove its significance for LIBs.
基金supported by the National Basic Research Program of China under Grant No. 2009CB421405the National Natural Science Foundation of China under Grant No. 40775035the Innovation Project of Chinese Academy of Sciences under Grant No. 076607M301
文摘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.
基金supported by the National Magnetic Confinement Fusion Science Foundation of China(Nos.2015GB102000 and 2014GB103000)
文摘Stationary long pulse plasma of high electron temperature was produced on EAST for the first time through an integrated control of plasma shape, divertor heat flux, particle exhaust, wall conditioning, impurity management, and the coupling of multiple heating and current drive power. A discharge with a lower single null divertor configuration was maintained for 103 s at a plasma current of 0.4 MA, q95 ≈7.0, a peak electron temperature of 〉4.5 keV, and a central density ne（0）-2.5×10^19 m^-3. The plasma current was nearly non-inductive （Vloop 〈0.05 V, poloidal beta - 0.9） driven by a combination of 0.6 MW lower hybrid wave at 2.45 GHz, 1.4 MW lower hybrid wave at 4.6 GHz, 0.5 MW electron cyclotron heating at 140 GHz, and 0.4 MW modulated neutral deuterium beam injected at 60 kV. This progress demonstrated strong synergy of electron cyclotron and lower hybrid electron heating, current drive, and energy confinement of stationary plasma on EAST. It further introduced an example of integrated ＂hybrid＂ operating scenario of interest to ITER and CFETR.
文摘We have observed that berberine prolonged life span and improved viability of pupae and climbing activity of imagoes of wild-type Drosophila melanogaster maintained at 23°C. As a continuation of our studies of berberine effect on life span, we were interested to evaluate the effect of berberine of life span in flies maintained at a higher temperature (28°C) known to accelerate aging in wild type flies. Considering that genetically or pharmacologically induced deficiency of TRP conversion into KYN prolonged life span in a Drosophila model, we compared the effects of berberine, a powerful inhibitor of kynurenine (KYN) formation from tryptophan (TRP), on life span in wild type and in Drosophila melanogaster mutants (vermilion) with deficient TRP-KYN metabolism maintained at 23°C and 28°C. High (28°C) ambient temperature decreased life span in both wild type and vermilion flies. Aging accelerating effect of high temperature was more pronounced in Oregon than in vermilion flies (-60% vs. -40% decrease of mean life span, resp). Berberine attenuated the aging-accelerating effect of high temperature. Effect of berberine was more pronounced in Oregon (+46%) than in vermilion (+22%) flies. The obtained data suggested the possible involvement of TRP-KYN metabolism in the aging-acceleration effect of the high temperature and in protective effect of berberine.
基金supported by National Key Technology R & D Program 2008BAK50B02National Basic Research Program of China under Grant No. 2009CB421405the National Natural Science Foundation of China under Grant Nos. 40730952 and 40805017
文摘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.
文摘Development of gas turbine oils that can be used in higher temperature conditions remains the greatest technological challenge. Though the maximum operating temperature of conventional lubricating oils is generally set around 100 ℃, or 140 ℃ for scavenged oils, it is predicted that the future will require oils to function at 200 ℃ or above. To find a clue to developing oils that can be used at higher temperatures, this study attempted to estimate service lives and operating temperature ranges of certain oils, including oils conforming to MIL-PRF-23699, which are deemed promising candidates for high-temperature applications, by analyzing their reaction rates of degradation and degeneration by oxidation. Among a number of methods used in the analyses of reaction rates, this study chose thermo-gravimetry （TG）, with which estimations can be made relatively easily.
文摘Distributed temperature sensing is known to provide sharp signals which are very efficient for mapping hydraulically active fractures in wellbores. High-resolution temperature sensing has specifically demonstrated its capacity to characterize very low flows in wellbores. But as sharp as they can be, temperature profiles are often difficult to decipher. The aim of the present work is to provide and to test the “Borehole Heat Budget Calculator” (BHB Calculator), which is implemented as a fast and easy to use tool for the quantitative analysis of depth-temperature profiles. The Calculator is suitable for most pumping and draining configurations, as the heat budget is generalized for modelling multidirectional flow systems within the same wellbore. The formatted worksheet allows the quick exploitation of temperature logs, and is applicable for the characterization of distributed fractures in long screened wellbores. Objectives of the heat modelling are to enhance the readability of complex depth-temperature data, as well as to quantify distribution of inflow intensities and temperatures with depth. The use of heat budget helps to clearly visualize how heat conduction and heat advection contributions are distributed along wellbores profiles. Calculations of inflow temperatures and their evolution through pumping duration is a prerequisite to infer about the nature of aquifer properties (i.e. conduits, distributed or discrete fractures, porous media), as well as to give insight information about the mapping of effective flow paths draining the aquifer. The efficiency and limitations of the BHB Calculator are being tested through high-resolution temperature logging, along with complementary flowmetering and televiewing logging in fractured aquifers located in the St-Lawrence Lowlands, Quebec, Canada.
文摘超高温灭菌(ultra-high temperature treated,UHT)乳是一类长期储存的液态乳品,其货架期长短直接影响着产品的市场竞争力和消费者满意度。UHT乳的货架期常常受到多种因素的影响,包括但不限于:即使经过UHT却仍在乳中残留的部分生物因子、货架期预测模型的合理性与准确性等。这些因素往往导致成品UHT乳在其储存货架期内发生如凝胶老化、脂肪上浮、风味改变、颜色改变等品质劣变现象。本文以近年来国内外对于影响UHT乳货架期稳定性的因素着手,分别解释了耐热芽孢、蛋白酶及脂肪酶影响UHT乳货架期寿命的机制,阐述了其引起的UHT乳货架期内的品质劣变现象;总结介绍了Arrhenius方程、多因素回归方程和BP神经网络3种货架期预测模型,在分别分析其运用环境的同时,对其优劣点进行了对比;最后在UHT乳的收奶端及生产端对延长UHT乳货架期的辅助技术进行了综述,以期从影响UHT乳货架期的相关因素入手,为今后UHT乳的生产及相关研究提供参考。
