The characteristics of tropical cyclone(TC) extreme rainfall events over Hainan Island from 1969 to 2014 are analyzed from the viewpoint of the TC maximum daily rainfall(TMDR) using daily station precipitation dat...The characteristics of tropical cyclone(TC) extreme rainfall events over Hainan Island from 1969 to 2014 are analyzed from the viewpoint of the TC maximum daily rainfall(TMDR) using daily station precipitation data from the Meteorological Information Center of the China Meteorological Administration, TC best-track data from the Shanghai Typhoon Institute,and NCEP/NCAR reanalysis data. The frequencies of the TMDR reaching 50, 100 and 250 mm show a decreasing trend[-0.7(10 yr)^(-1)], a weak decreasing trend [-0.2(10 yr)^(-1)] and a weak increasing trend [0.1(10 yr)^(-1)], respectively. For seasonal variations, the TMDR of all intensity grades mainly occurs from July to October, with the frequencies of TMDR 50 mm and 100 mm peaking in September and the frequency of TMDR 250 mm [TC extreme rainstorm(TCER) events]peaking in August and September. The western region(Changjiang) of the Island is always the rainfall center, independent of the intensity or frequencies of different intensity grades. The causes of TCERs are also explored and the results show that topography plays a key role in the characteristics of the rainfall events. TCERs are easily induced on the windward slopes of Wuzhi Mountain, with the coordination of TC tracks and TC wind structure. A slower speed of movement, a stronger TC intensity and a farther westward track are all conducive to extreme rainfall events. A weaker northwestern Pacific subtropical high is likely to make the 500-h Pa steering flow weaker and results in slower TC movement, whereas a stronger South China Sea summer monsoon can carry a higher moisture flux. These two environmental factors are both favorable for TCERs.展开更多
[ Objective] This study aimed to characterize the structure of soybean glycinin affected by limited enzymatic hydrolysis. [ Method ] The glycinin was limitedly hydrolyzed by alkaline protease; then the SDS-polyacrylam...[ Objective] This study aimed to characterize the structure of soybean glycinin affected by limited enzymatic hydrolysis. [ Method ] The glycinin was limitedly hydrolyzed by alkaline protease; then the SDS-polyacrylamide gel electrophoresis (SDS-PAGE), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (fTIR) and other means were performed to characterize the glyeinin structure changing during the hydrolysis process. [ Result] SDS-PAGE analysis showed that the subunit contem of glycinin significantly decreased after hydrolysis, and acidic subunits were more susceptible to hydrolysis than alkaline subunits. The scanning electron microscopy revealed that the structure of glycinin powder changed greatly after hydrolysis. The I^TIR results showed that the propor- tions of all conformations of glycinin changed greatly during hydrolysis process. In addition, the protein hydrophobicity and sulfhydryl content were also significantly influenced by hydrolysis. [ Conclusion] The enzymatic hydrolysis greatly changed the conformations of glyeinin, and the change was dependent on the degree of hy- drolysis.展开更多
Defining the structure characteristics of amorphous materials is one of the fundamental problems that need to be solved urgently in complex materials because of their complex structure and long-range disorder.In this ...Defining the structure characteristics of amorphous materials is one of the fundamental problems that need to be solved urgently in complex materials because of their complex structure and long-range disorder.In this study,we develop an interpretable deep learning model capable of accurately classifying amorphous configurations and characterizing their structural properties.The results demonstrate that the multi-dimensional hybrid convolutional neural network can classify the two-dimensional(2D)liquids and amorphous solids of molecular dynamics simulation.The classification process does not make a priori assumptions on the amorphous particle environment,and the accuracy is 92.75%,which is better than other convolutional neural networks.Moreover,our model utilizes the gradient-weighted activation-like mapping method,which generates activation-like heat maps that can precisely identify important structures in the amorphous configuration maps.We obtain an order parameter from the heatmap and conduct finite scale analysis of this parameter.Our findings demonstrate that the order parameter effectively captures the amorphous phase transition process across various systems.These results hold significant scientific implications for the study of amorphous structural characteristics via deep learning.展开更多
Hemodynamics plays a crucial role in the development and progression of coronary atherosclerosis,which is prone to occur in branch bifurcation.A n individual aortic-coronary artery model and three changed bifurcation ...Hemodynamics plays a crucial role in the development and progression of coronary atherosclerosis,which is prone to occur in branch bifurcation.A n individual aortic-coronary artery model and three changed bifurcation angle models are constructed by Mimics and Freeform based on computed tomography angiography.The influence of different coronary bifurcation angles between left main(LM),left anterior descending(LAD),and left circumflex(LCX)on the blood flow field and related hemodynamic parameters are studied.It is shown that a wider bifurcation angle between LAD and LCX can cause a wider low-wall shear stress area,leading to atherosclerosis.Similarly,a decreased angle between LM and LAD is predisposed to prevent atherosclerosis.The results help to better understand the hemodynamic causes of atherosclerosis with various bifurcation angles in coronary arteries and to provide guidance for clinical assessment and prevention.展开更多
Traditional monopulse radar cannot resolve two targets present in one range and Doppler cell by means of the monopulse ratio. A novel algorithm is proposed to estimate the directions of two steady targets with two pul...Traditional monopulse radar cannot resolve two targets present in one range and Doppler cell by means of the monopulse ratio. A novel algorithm is proposed to estimate the directions of two steady targets with two pulses. The algorithm has a closedform expression and its variance is derived at high signal-to-noise ratios(SNRs). Furthermore, the pulse pair selection criterion and the estimation method with multiple pulses are given. Finally, some numerical results are shown to validate the proposed algorithm and the effect of slight target fluctuations is tested.展开更多
Background HIRFL is a heavy ion accelerator built by the Institute of Modern Physics,Chinese Academy of Sciences,which constitutes a total length of over 900 m by the SFC,SSC,CSRm,CSRe and so on.It bears a lot of rese...Background HIRFL is a heavy ion accelerator built by the Institute of Modern Physics,Chinese Academy of Sciences,which constitutes a total length of over 900 m by the SFC,SSC,CSRm,CSRe and so on.It bears a lot of research task of the country,so to ensure its safe operation is very important.Purpose Cool-water system is a key part in HIRFL,and the parameters of the cool-water system need to be monitored before an accident occurs.Methods This article describes three aspects of the system,from the water leakage detection,pressure monitoring,to the water-level monitoring.A complete monitor system was designed and constructed,including the hardware structure;the data transfer mode,as well as specific control program.C++,FLASH and SCADA are used in the monitoring system.Results Fault alarm was performed timely and accurately by the monitoring system,and many accidents were avoided.Conclusion Water system monitoring is an important part of the accelerator control system.It will also play a major role in the construction of large-scale scientific device named HIAF in the further.展开更多
由于资源储量丰富,钠离子电池已经成为下一代储能电池的有力候选方案之一.过渡金属硒化物由于具有易于制备、导电性能较好等优点而引起广泛关注.本文使用溶剂热方法成功地制备出六方相CuSe纳米片,并将其作为钠离子电池负极材料,结合多...由于资源储量丰富,钠离子电池已经成为下一代储能电池的有力候选方案之一.过渡金属硒化物由于具有易于制备、导电性能较好等优点而引起广泛关注.本文使用溶剂热方法成功地制备出六方相CuSe纳米片,并将其作为钠离子电池负极材料,结合多种测试及表征手段对其储钠性能与电化学反应机理进行了研究.电化学测试表明CuSe具有优异的电化学性能.在5 A g^(-1)电流密度下的可逆容量为183.5 mAh g^(-1),容量保持率为70.7%(相对0.1 A g^(-1)电流密度下的可逆容量而言).在2 A g^(-1)循环800圈后,容量保持率高达97.4%.非原位X射线粉末衍射和选区电子衍射测试结果表明,CuSe在储钠过程中会发生不可逆的转化反应生成Cu_(2-x)Se,后续的循环实际上是Cu_(2-x)Se进行钠离子的转化反应.展开更多
Maltose is a natural α-(1,4)-linked disaccharide with wide applications in food industries and microbial fermentation. However,maltose has scarcely been used for in vitro biosynthesis, possibly because its phosphoryl...Maltose is a natural α-(1,4)-linked disaccharide with wide applications in food industries and microbial fermentation. However,maltose has scarcely been used for in vitro biosynthesis, possibly because its phosphorylation by maltose phosphorylase (MP)yields β-glucose 1-phosphate (β-G1P) that cannot be utilized by α-phosphoglucomutase (α-PGM) commonly found in in vitrosynthetic enzymatic biosystems previously constructed by our group. Herein, we designed an in vitro synthetic enzymaticreaction module comprised of MP, β-phosphoglucomutase (β-PGM), and polyphosphate glucokinase (PPGK) for thestoichiometric conversion of each maltose molecule to two glucose 6-phosphate (G6P) molecules. Based on this syntheticmodule, we further constructed two in vitro synthetic biosystems to produce bioelectricity and fructose 1,6-diphosphate (FDP),respectively. The 14-enzyme biobattery achieved a Faraday efficiency of 96.4% and a maximal power density of 0.6mW/cm^(2),whereas the 5-enzyme in vitro FDP-producing biosystem yielded 187.0mM FDP from 50 g/L (139mM) maltose by adopting afed-batch substrate feeding strategy. Our study not only suggests new application scenarios for maltose but also provides novelstrategies for the high-efficient production of bioelectricity and value-added biochemicals.展开更多
The composite-drought index (CI), improved weighted average of precipitation index (IWAP), and the objective identification technique for regional extreme events (OITREE) were employed to detect China's regiona...The composite-drought index (CI), improved weighted average of precipitation index (IWAP), and the objective identification technique for regional extreme events (OITREE) were employed to detect China's regional meteorolo- gical drought events (CRMDEs) during 1961-2010. Compared with existing references, CI and IWAP both showed strong ability in identifying CRMDEs. Generally, the results of CI and IWAP were consistent, especially for extreme and severe CRMDEs. During 1961-2010, although the frequencies of extreme and severe CRMDEs based on C! and IWAP both showed weak decreasing trends, the two mean-integrated indices both showed increasing but not signifi- cant trends. However, the results of IWAP were more reasonable than CI's in two aspects. Firstly, the monthly fre- quency of extreme and severe CRMDEs based on IWAP showed a clear seasonal variation, which coincided with the seasonal variation of the East Asian monsoon over central-eastern China, whereas the frequency based on CI presen- ted a much weaker seasonal variation. Secondly, the two sets of results were sometimes inconsistent with respect to the start and end times of a CRMDE, and CRMDEs based on CI generally showed two unreasonable phenomena: (1) under non-drought conditions, a severe drought stage could suddenly occur in a large area; and (2) during the follow- ing period, drought could alleviate gradually in cases of non-precipitation. Comparative analysis suggested that the IWAP drought index possesses obvious advantages in detecting and monitoring regional drought events.展开更多
Introduction In this paper,we detail the architecture,design,and testing of an accurate and usable electronic cooler control system for the cooling storage main ring at the Heavy Ion Research Facility,Lanzhou,China(HI...Introduction In this paper,we detail the architecture,design,and testing of an accurate and usable electronic cooler control system for the cooling storage main ring at the Heavy Ion Research Facility,Lanzhou,China(HIRFL-CSRm),and present the results of its use.Purpose A control system must manage devices with a high degree of accuracy to satisfy various physical requirements,and to ensure the accuracy of the data acquisition and control characteristics.Methods and materials The software for the system,based on the C++,was developed following the model-view-controller architecture pattern.On the hardware side,an I-7017R module was adopted for analog-to-digital conversion and an I-7065D module for electronic delay.The communication protocol was analyzed,discussed,and implemented.Results The control system was then tested with the 12C3+carbon beam at HIRFL-CSRm.The fast reaction time and high-precision data processing exhibited during beam tuning verified the stability and maintainability of the proposed control system.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.41375056),the National Natural Science Foundation of China (Grant No.41675042)the National Science-Technology Support Plan Project (Grant No.2013BAK05B03)+1 种基金the Hainan Meteorological Service Research Project (Grant No.HNQXQN201402)the China Meteorological Administration Forecaster Special Project (Grant No.CMAYBY2015-058)
文摘The characteristics of tropical cyclone(TC) extreme rainfall events over Hainan Island from 1969 to 2014 are analyzed from the viewpoint of the TC maximum daily rainfall(TMDR) using daily station precipitation data from the Meteorological Information Center of the China Meteorological Administration, TC best-track data from the Shanghai Typhoon Institute,and NCEP/NCAR reanalysis data. The frequencies of the TMDR reaching 50, 100 and 250 mm show a decreasing trend[-0.7(10 yr)^(-1)], a weak decreasing trend [-0.2(10 yr)^(-1)] and a weak increasing trend [0.1(10 yr)^(-1)], respectively. For seasonal variations, the TMDR of all intensity grades mainly occurs from July to October, with the frequencies of TMDR 50 mm and 100 mm peaking in September and the frequency of TMDR 250 mm [TC extreme rainstorm(TCER) events]peaking in August and September. The western region(Changjiang) of the Island is always the rainfall center, independent of the intensity or frequencies of different intensity grades. The causes of TCERs are also explored and the results show that topography plays a key role in the characteristics of the rainfall events. TCERs are easily induced on the windward slopes of Wuzhi Mountain, with the coordination of TC tracks and TC wind structure. A slower speed of movement, a stronger TC intensity and a farther westward track are all conducive to extreme rainfall events. A weaker northwestern Pacific subtropical high is likely to make the 500-h Pa steering flow weaker and results in slower TC movement, whereas a stronger South China Sea summer monsoon can carry a higher moisture flux. These two environmental factors are both favorable for TCERs.
基金Supported by 863 Program(2006AA10Z330)New Century High-level Talent Project in Hubei Province[(2003)31]
文摘[ Objective] This study aimed to characterize the structure of soybean glycinin affected by limited enzymatic hydrolysis. [ Method ] The glycinin was limitedly hydrolyzed by alkaline protease; then the SDS-polyacrylamide gel electrophoresis (SDS-PAGE), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (fTIR) and other means were performed to characterize the glyeinin structure changing during the hydrolysis process. [ Result] SDS-PAGE analysis showed that the subunit contem of glycinin significantly decreased after hydrolysis, and acidic subunits were more susceptible to hydrolysis than alkaline subunits. The scanning electron microscopy revealed that the structure of glycinin powder changed greatly after hydrolysis. The I^TIR results showed that the propor- tions of all conformations of glycinin changed greatly during hydrolysis process. In addition, the protein hydrophobicity and sulfhydryl content were also significantly influenced by hydrolysis. [ Conclusion] The enzymatic hydrolysis greatly changed the conformations of glyeinin, and the change was dependent on the degree of hy- drolysis.
基金National Natural Science Foundation of China(Grant No.11702289)the Key Core Technology and Generic Technology Research and Development Project of Shanxi Province,China(Grant No.2020XXX013)the National Key Research and Development Project of China。
文摘Defining the structure characteristics of amorphous materials is one of the fundamental problems that need to be solved urgently in complex materials because of their complex structure and long-range disorder.In this study,we develop an interpretable deep learning model capable of accurately classifying amorphous configurations and characterizing their structural properties.The results demonstrate that the multi-dimensional hybrid convolutional neural network can classify the two-dimensional(2D)liquids and amorphous solids of molecular dynamics simulation.The classification process does not make a priori assumptions on the amorphous particle environment,and the accuracy is 92.75%,which is better than other convolutional neural networks.Moreover,our model utilizes the gradient-weighted activation-like mapping method,which generates activation-like heat maps that can precisely identify important structures in the amorphous configuration maps.We obtain an order parameter from the heatmap and conduct finite scale analysis of this parameter.Our findings demonstrate that the order parameter effectively captures the amorphous phase transition process across various systems.These results hold significant scientific implications for the study of amorphous structural characteristics via deep learning.
基金The authors are grateful for the support of the Specialized Research Fund for the Doctoral Program of Higher Education(Grant 20131103110025)the Key Program of Science and Technology Plan of Beijing Municipal Education Commission(Grant KZ201710005006)the National Natural Science Foundation of China(Grant 81601557).
文摘Hemodynamics plays a crucial role in the development and progression of coronary atherosclerosis,which is prone to occur in branch bifurcation.A n individual aortic-coronary artery model and three changed bifurcation angle models are constructed by Mimics and Freeform based on computed tomography angiography.The influence of different coronary bifurcation angles between left main(LM),left anterior descending(LAD),and left circumflex(LCX)on the blood flow field and related hemodynamic parameters are studied.It is shown that a wider bifurcation angle between LAD and LCX can cause a wider low-wall shear stress area,leading to atherosclerosis.Similarly,a decreased angle between LM and LAD is predisposed to prevent atherosclerosis.The results help to better understand the hemodynamic causes of atherosclerosis with various bifurcation angles in coronary arteries and to provide guidance for clinical assessment and prevention.
文摘Traditional monopulse radar cannot resolve two targets present in one range and Doppler cell by means of the monopulse ratio. A novel algorithm is proposed to estimate the directions of two steady targets with two pulses. The algorithm has a closedform expression and its variance is derived at high signal-to-noise ratios(SNRs). Furthermore, the pulse pair selection criterion and the estimation method with multiple pulses are given. Finally, some numerical results are shown to validate the proposed algorithm and the effect of slight target fluctuations is tested.
文摘Background HIRFL is a heavy ion accelerator built by the Institute of Modern Physics,Chinese Academy of Sciences,which constitutes a total length of over 900 m by the SFC,SSC,CSRm,CSRe and so on.It bears a lot of research task of the country,so to ensure its safe operation is very important.Purpose Cool-water system is a key part in HIRFL,and the parameters of the cool-water system need to be monitored before an accident occurs.Methods This article describes three aspects of the system,from the water leakage detection,pressure monitoring,to the water-level monitoring.A complete monitor system was designed and constructed,including the hardware structure;the data transfer mode,as well as specific control program.C++,FLASH and SCADA are used in the monitoring system.Results Fault alarm was performed timely and accurately by the monitoring system,and many accidents were avoided.Conclusion Water system monitoring is an important part of the accelerator control system.It will also play a major role in the construction of large-scale scientific device named HIAF in the further.
文摘由于资源储量丰富,钠离子电池已经成为下一代储能电池的有力候选方案之一.过渡金属硒化物由于具有易于制备、导电性能较好等优点而引起广泛关注.本文使用溶剂热方法成功地制备出六方相CuSe纳米片,并将其作为钠离子电池负极材料,结合多种测试及表征手段对其储钠性能与电化学反应机理进行了研究.电化学测试表明CuSe具有优异的电化学性能.在5 A g^(-1)电流密度下的可逆容量为183.5 mAh g^(-1),容量保持率为70.7%(相对0.1 A g^(-1)电流密度下的可逆容量而言).在2 A g^(-1)循环800圈后,容量保持率高达97.4%.非原位X射线粉末衍射和选区电子衍射测试结果表明,CuSe在储钠过程中会发生不可逆的转化反应生成Cu_(2-x)Se,后续的循环实际上是Cu_(2-x)Se进行钠离子的转化反应.
基金the National Key Research and Development Program of China(Grant number 2021YFA0910601)the National Natural Science Foundation of China(Grant numbers 32022044 and 32001027).
文摘Maltose is a natural α-(1,4)-linked disaccharide with wide applications in food industries and microbial fermentation. However,maltose has scarcely been used for in vitro biosynthesis, possibly because its phosphorylation by maltose phosphorylase (MP)yields β-glucose 1-phosphate (β-G1P) that cannot be utilized by α-phosphoglucomutase (α-PGM) commonly found in in vitrosynthetic enzymatic biosystems previously constructed by our group. Herein, we designed an in vitro synthetic enzymaticreaction module comprised of MP, β-phosphoglucomutase (β-PGM), and polyphosphate glucokinase (PPGK) for thestoichiometric conversion of each maltose molecule to two glucose 6-phosphate (G6P) molecules. Based on this syntheticmodule, we further constructed two in vitro synthetic biosystems to produce bioelectricity and fructose 1,6-diphosphate (FDP),respectively. The 14-enzyme biobattery achieved a Faraday efficiency of 96.4% and a maximal power density of 0.6mW/cm^(2),whereas the 5-enzyme in vitro FDP-producing biosystem yielded 187.0mM FDP from 50 g/L (139mM) maltose by adopting afed-batch substrate feeding strategy. Our study not only suggests new application scenarios for maltose but also provides novelstrategies for the high-efficient production of bioelectricity and value-added biochemicals.
基金Supported by the National Natural Science Foundation of China(41175075 and 91224004)China Meteorological Administration Special Foundation on Climate Change(CCSF201333)
文摘The composite-drought index (CI), improved weighted average of precipitation index (IWAP), and the objective identification technique for regional extreme events (OITREE) were employed to detect China's regional meteorolo- gical drought events (CRMDEs) during 1961-2010. Compared with existing references, CI and IWAP both showed strong ability in identifying CRMDEs. Generally, the results of CI and IWAP were consistent, especially for extreme and severe CRMDEs. During 1961-2010, although the frequencies of extreme and severe CRMDEs based on C! and IWAP both showed weak decreasing trends, the two mean-integrated indices both showed increasing but not signifi- cant trends. However, the results of IWAP were more reasonable than CI's in two aspects. Firstly, the monthly fre- quency of extreme and severe CRMDEs based on IWAP showed a clear seasonal variation, which coincided with the seasonal variation of the East Asian monsoon over central-eastern China, whereas the frequency based on CI presen- ted a much weaker seasonal variation. Secondly, the two sets of results were sometimes inconsistent with respect to the start and end times of a CRMDE, and CRMDEs based on CI generally showed two unreasonable phenomena: (1) under non-drought conditions, a severe drought stage could suddenly occur in a large area; and (2) during the follow- ing period, drought could alleviate gradually in cases of non-precipitation. Comparative analysis suggested that the IWAP drought index possesses obvious advantages in detecting and monitoring regional drought events.
基金This study is supported by the National Natural Science Foundation of China(u1232123).
文摘Introduction In this paper,we detail the architecture,design,and testing of an accurate and usable electronic cooler control system for the cooling storage main ring at the Heavy Ion Research Facility,Lanzhou,China(HIRFL-CSRm),and present the results of its use.Purpose A control system must manage devices with a high degree of accuracy to satisfy various physical requirements,and to ensure the accuracy of the data acquisition and control characteristics.Methods and materials The software for the system,based on the C++,was developed following the model-view-controller architecture pattern.On the hardware side,an I-7017R module was adopted for analog-to-digital conversion and an I-7065D module for electronic delay.The communication protocol was analyzed,discussed,and implemented.Results The control system was then tested with the 12C3+carbon beam at HIRFL-CSRm.The fast reaction time and high-precision data processing exhibited during beam tuning verified the stability and maintainability of the proposed control system.