Zinc-air batteries(ZABs)are promising energy storage systems because of high theoretical energy density,safety,low cost,and abundance of zinc.However,the slow multi-step reaction of oxygen and heavy reliance on noble-...Zinc-air batteries(ZABs)are promising energy storage systems because of high theoretical energy density,safety,low cost,and abundance of zinc.However,the slow multi-step reaction of oxygen and heavy reliance on noble-metal catalysts hinder the practical applications of ZABs.Therefore,feasible and advanced non-noble-metal elec-trocatalysts for air cathodes need to be identified to promote the oxygen catalytic reaction.In this review,we initially introduced the advancement of ZABs in the past two decades and provided an overview of key developments in this field.Then,we discussed the work-ing mechanism and the design of bifunctional electrocatalysts from the perspective of morphology design,crystal structure tuning,interface strategy,and atomic engineering.We also included theoretical studies,machine learning,and advanced characterization technologies to provide a comprehensive understanding of the structure-performance relationship of electrocatalysts and the reaction pathways of the oxygen redox reactions.Finally,we discussed the challenges and prospects related to designing advanced non-noble-metal bifunctional electrocatalysts for ZABs.展开更多
For a general normed vector space,a special optimal value function called a maximal time function is considered.This covers the farthest distance function as a special case,and has a close relationship with the smalle...For a general normed vector space,a special optimal value function called a maximal time function is considered.This covers the farthest distance function as a special case,and has a close relationship with the smallest enclosing ball problem.Some properties of the maximal time function are proven,including the convexity,the lower semicontinuity,and the exact characterizations of its subdifferential formulas.展开更多
BACKGROUND:We aimed to observe the dynamic changes in glucose metabolic reprogrammingrelated parameters and their ability to predict neurological prognosis and all-cause mortality in cardiac arrest patients after the ...BACKGROUND:We aimed to observe the dynamic changes in glucose metabolic reprogrammingrelated parameters and their ability to predict neurological prognosis and all-cause mortality in cardiac arrest patients after the restoration of spontaneous circulation(ROSC).METHODS:Adult cardiac arrest patients after ROSC who were admitted to the emergency or cardiac intensive care unit of the First Aflliated Hospital of Dalian Medical University from August 1,2017,to May 30,2021,were enrolled.According to 28-day survival,the patients were divided into a non-survival group(n=82) and a survival group(n=38).Healthy adult volunteers(n=40) of similar ages and sexes were selected as controls.The serum levels of glucose metabolic reprogrammingrelated parameters(lactate dehydrogenase [LDH],lactate and pyruvate),neuron-specific enolase(NSE) and interleukin 6(IL-6) were measured on days 1,3,and 7 after ROSC.The Acute Physiology and Chronic Health Evaluation II(APACHE II) score and Sequential Organ Failure Assessment(SOFA) score were calculated.The Cerebral Performance Category(CPC) score was recorded on day 28 after ROSC.RESULTS:Following ROSC,the serum LDH(607.0 U/L vs.286.5 U/L),lactate(5.0 mmol/L vs.2.0 mmol/L),pyruvate(178.0 μmol/L vs.70.9 μmol/L),and lactate/pyruvate ratio(34.1 vs.22.1) significantly increased and were higher in the non-survivors than in the survivors on admission(all P<0.05).Moreover,the serum LDH,pyruvate,IL-6,APACHE II score,and SOFA score on days 1,3 and 7 after ROSC were significantly associated with 28-day poor neurological prognosis and 28-day all-cause mortality(all P<0.05).The serum LDH concentration on day 1 after ROSC had an area under the receiver operating characteristic curve(AUC) of 0.904 [95% confidence interval [95% CI]:0.851–0.957]) with 96.8% specificity for predicting 28-day neurological prognosis and an AUC of 0.950(95% CI:0.911–0.989) with 94.7% specificity for predicting 28-day all-cause mortality,which was the highest among the glucose metabolic reprogramming-related parameters tested.CONCLUSION:Serum parameters related to glucose metabolic reprogramming were significantly increased after ROSC.Increased serum LDH and pyruvate levels,and lactate/pyruvate ratio may be associated with 28-day poor neurological prognosis and all-cause mortality after ROSC,and the predictive eflcacy of LDH during the first week was superior to others.展开更多
Anti-glomerular basement membrane(anti-GBM)disease is a rare small vessel vasculitis representing the most aggressive form of autoimmune glomerulonephritis.[1,2]Its overall incidence ranges from 0.60 to 1.79 per milli...Anti-glomerular basement membrane(anti-GBM)disease is a rare small vessel vasculitis representing the most aggressive form of autoimmune glomerulonephritis.[1,2]Its overall incidence ranges from 0.60 to 1.79 per million population annually.[1]Anti-GBM disease is mediated by abnormal anti-GBM antibody production,which mainly targets GBM and thus contributes to rapid progressive glomerulonephritis with a distinctive pattern of diffuse crescentic formation in the glomeruli.展开更多
目的:对比分析双眼三焦点IOL(AT LISA tri 839MP IOL)植入与一眼植入AT LISA tri 839MP IOL而另一眼植入非球面单焦点IOL患者术后视觉相关生活质量。方法:前瞻性临床研究。收集2018-05/2019-08在我院行白内障超声乳化联合三焦点AT LISA ...目的:对比分析双眼三焦点IOL(AT LISA tri 839MP IOL)植入与一眼植入AT LISA tri 839MP IOL而另一眼植入非球面单焦点IOL患者术后视觉相关生活质量。方法:前瞻性临床研究。收集2018-05/2019-08在我院行白内障超声乳化联合三焦点AT LISA tri 839MP IOL植入的患者45例,按是否双眼植入AT LISA tri 839MP IOL分为两组,双眼植入者24例纳入双眼三焦点组;一眼植入AT LISA tri 839MP IOL而另一眼植入非球面单焦点IOL者21例纳入单眼三焦点组。术后3mo,检测两组患者裸眼视力及等效球镜度,并通过中国版视功能指数量表(VF-14-CN)评价视觉相关生活质量,评估日常生活脱镜率及满意度。结果:术后3mo,双眼三焦点组和单眼三焦点组患者双眼裸眼远、中、近视力均无明显差异(P>0.05),两组患者VF-14-CN问卷得分(96.2±0.50、92.43±1.32分)、日常生活脱镜率(96%、90%)及患者主观满意度(96%、95%)均无差异(P>0.05)。结论:双眼植入AT LISA tri 839MP IOL和一眼植入AT LISA tri 839MP IOL而另一眼植入非球面单焦点IOL的患者术后均具有良好的双眼裸眼远、中、近视力,术后视觉相关生活质量、脱镜率、满意度无明显差异。对一眼不适合植入三焦点IOL或既往一眼已植入非球面单焦点IOL的患者,可考虑另一眼行三焦点IOL植入以满足患者双眼全程视力的要求。展开更多
Soil microbial biomass is an important indicator to measure the dynamic changes of soil carbon pool.It is of great signifi cance to understand the dynamics of soil microbial biomass in plantation for rational manageme...Soil microbial biomass is an important indicator to measure the dynamic changes of soil carbon pool.It is of great signifi cance to understand the dynamics of soil microbial biomass in plantation for rational management and cultivation of plantation.In order to explore the temporal dynamics and infl uencing factors of soil microbial biomass of Keteleeria fortunei var.cyclolepis at diff erent stand ages,the plantation of diff erent ages(young forest,5 years;middle-aged forest,22 years;mature forest,40 years)at the Guangxi Daguishan forest station of China were studied to examine the seasonal variation of their microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN)by chloroform fumigation extraction method.It was found that among the forests of diff erent age,MBC and MBN diff ered signifi cantly in the 0–10 cm soil layer,and MBN diff ered signifi cantly in the 10–20 cm soil layer,but there was no signifi cant diff erence in MBC for the 10–20 cm soil layer or in either MBC or MBN for the 20–40 cm soil layer.With increasing maturity of the forest,MBC gradually decreased in the 0–10 cm soil layer and increased fi rstly and then decreased in the 10–20 cm and 20–40 cm soil layers,and MBN increased fi rstly and then decreased in all three soil layers.As the soil depth increased,both MBC and MBN gradually decreased for all three forests.The MBC and MBN basically had the same seasonal variation in all three soil layers of all three forests,i.e.,high in the summer and low in the winter.Correlation analysis showed that MBC was signifi cantly positively correlated with soil organic matter,total nitrogen,and soil moisture,whereas MBN was signifi cantly positively correlated with soil total nitrogen.It showed that soil moisture content was the main factor determining the variation of soil microbial biomass by Redundancy analysis.The results showed that the soil properties changed continuously as the young forest grew into the middle-aged forest,which increased soil microbial biomass and enriched the soil nutrients.However,the soil microbial biomass declined as the middle-age forest continued to grow,and the soil nutrients were reduced in the mature forest.展开更多
A dual-frequency(105/140 GHz)MW-level continuous-wave gyrotron was developed for fusion application at Institute of Applied Electronics,China Academy of Engineering Physics.This gyrotron employs a cylindrical cavity w...A dual-frequency(105/140 GHz)MW-level continuous-wave gyrotron was developed for fusion application at Institute of Applied Electronics,China Academy of Engineering Physics.This gyrotron employs a cylindrical cavity working in the TE18,7 mode at 105 GHz and the TE24,9 mode at 140 GHz.A triode magnetron injection gun and a built-in quasi-optical mode converter were designed to operate at these two frequencies.For the proof-test phase,the gyrotron was equipped with a single-disk boron nitride window to achieve radio frequency output with a power of~500 k W for a short-pulse duration.In the preliminary short-pulse proof-test in the first quarter of2021,the dual-frequency gyrotron achieved output powers of 300 k W at 105 GHz and 540 k W at140 GHz,respectively,under 5 Hz 1 ms continuous pulse-burst operations.Power upgrade and pulse-width extension were hampered by the limitation of the high-voltage power supply and output window.This gyrotron design was preliminarily validated.展开更多
Liquidambar formosana Hance is an attractive landscape tree species because its leaves gradually change from green to red,purple or orange in autumn.In this study,the red variety of L.formosana was used to establish a...Liquidambar formosana Hance is an attractive landscape tree species because its leaves gradually change from green to red,purple or orange in autumn.In this study,the red variety of L.formosana was used to establish a quantitative model of leaf color.Physiological changes in leaf color,pigment levels,enzyme activity,photosynthetic fluorescence characteristics and chloroplast ultrastructure were monitored.The relationship between leaf color and physiological structure indices was quantitatively analyzed to systematically explore the mechanisms behind leaf color.Our data showed that with a decrease in external temperatures,chloroplast numbers and sizes gradually decreased,thylakoid membranes became distorted,and chlorophyll synthesis was blocked and gradually decreased.As a result,chloroplast membranes could not be biosynthesized normally;net photosynthesis,maximum and actual photochemical efficiency,and rate of electron transfer decreased rapidly.Excess light energy caused leaf photoinhibition.With intensification of photoinhibition,leaves protected themselves using two mechanisms.In the first,anthocyanin synthesis was promoted by increasing chalcone isomerase and flavonoid glycosyltransferase activities and soluble sugar content so as to increase anthocyanin to filter light and eliminate reactive oxygen species to reduce photoinhibition.In the second,excessive light energy was consumed in the form of heat energy by increasing the non-photochemical quenching coefficient.These processes tuned the leaves red.展开更多
The widespread use of gastrointestinal bleeding prophylaxis in critically ill patients was one of the most controversial issues. Since few studies reported the incidence of gastrointestinal bleeding in mechanically ve...The widespread use of gastrointestinal bleeding prophylaxis in critically ill patients was one of the most controversial issues. Since few studies reported the incidence of gastrointestinal bleeding in mechanically ventilated patients, this study aimed to identify the incidence and risk factors related to gastrointestinal bleeding in patients undergoing mechanical ventilation for more than 48 hours. A total of 283 IOU patients who had received mechanical ventilation for longer than 48 hours at a provincial hospital affiliated to Shandong University from January 1,2007 to December 31, 2009 were analyzed retrospectively. Those were excluded from the study if they had a history of gastrointestinal bleeding or ulceration, recent gastrointestinal surgery, brain death and active bleeding from the nose or throat. Demographic data of the patients included patient age, diagnosis on admission, duration of ICU stay, duration of ventilation, patterns and parameters of ventilation, ICU mortality, APACHE II score, multiple organ dysfunction, and indexes of biochemistry, kidney function, liver function and coagulation function. Risk factors of gastrointestinal bleeding were analyzed by univariate analysis and multiple logistic regression analysis. In the 242 patients who were given mechanical ventilation longer than 48 hours, the incidence of gastrointestinal bleeding was 46.7%. The bleeding in 3.3% of the patients was clinically significant. Significant risk factors were peak inspiratory pressure 〉30cmH2O, renal failure, liver failure, PLT count〈50xl09/L and prolonged APTT. Enteral nutrition had a beneficial effect on gastrointestinal bleeding. However, the multiple logistic regression analysis revealed that the independent risk factors of gastrointestinal bleeding were as follows： high pressure ventilator setting 〉 30cmH2O（RR=3.478, 95%CI=2.208-10.733）, renal failure（RR=1 .687, 95%CI=1.098-3.482）, PLT count〈50×10^9/L （RR=3.762, 95%CI=2.346-14.685）, and prolonged APTT（RR=5.368, 95%CI=2.487-11.266）. Enteral nutrition（RR=0.436, 95%CI= 0.346-0.764） was the independent protective factor. The incidence of gastrointestinal bleeding was high in the patients who received mechanical ventilation, and bleeding usually occurred within the first 48 hours. High pressure ventilator setting, renal failure, decreased PLT count and prolonged APTT were the significant risk factors of gastrointestinal bleeding. However, enteral nutrition was the independent protective factor.展开更多
Topological materials have novel properties both in their bulk and boundaries,thereby attracting a wide interest in the theoretical and experimental communities.The recent development of the topological quantum chemis...Topological materials have novel properties both in their bulk and boundaries,thereby attracting a wide interest in the theoretical and experimental communities.The recent development of the topological quantum chemistry and symmetrybased indicator theory in this field has significantly simplified the procedure for determining the topological properties of nonmagnetic crystalline materials.Accordingly,a large number of new topological materials have been found by scanning large crystal databases.This study provides details on the algorithm used in the Catalogue of Topological Electronic Materials.Moreover,based on the algorithm,we develop an automatic package named SymTopo,which calculates the symmetry representations of any given nonmagnetic crystalline material and predicts its topological properties.This package may facilitate the discovery of more topological materials in the future.展开更多
In the paper, we illustrate the importance of the concept of mobile network computer from a technological perspective. Because of the usefulness of mobile network computers, with the growth of the Internet of things, ...In the paper, we illustrate the importance of the concept of mobile network computer from a technological perspective. Because of the usefulness of mobile network computers, with the growth of the Internet of things, mobile network computers may include not only TV box audio-visual equipment, wireless household appliances, and mobile communication equipment, but may also include devices such as intelligent foot rings, smart watches, smart glasses, smart shoes and smart coats. Considering the different types of networks, e.g. IP multimedia Subsystem(IMS), we explain why some network elements are inaccurate and misleading from a technological perspective. We aim to popularize the concept of mobile network computers for its accuracy and importance, which better define modern mobile terminals and reflects the nature of multiple mobile terminals based on the structure of their integrated computers and the capabilities of processing multimedia. In the computer and Internet age, network computers and mobile network computers are the main terminals of fixed and mobile networks, respectively. Therefore, based on the concept of mobile network computers, we discuss the future of information society.展开更多
The layered pavements usually exhibit complicated mechanical properties with the effect of complex material properties under external environment.In some cases,such as launching missiles or rockets,layered pavements a...The layered pavements usually exhibit complicated mechanical properties with the effect of complex material properties under external environment.In some cases,such as launching missiles or rockets,layered pavements are required to bear large impulse load.However,traditional methods cannot non-destructively and quickly detect the internal structural of pavements.Thus,accurate and fast prediction of the mechanical properties of layered pavements is of great importance and necessity.In recent years,machine learning has shown great superiority in solving nonlinear problems.In this work,we present a method of predicting the maximum deflection and damage factor of layered pavements under instantaneous large impact based on random forest regression with the deflection basin parameters obtained from falling weight deflection testing.The regression coefficient R^(2)of testing datasets are above 0.94 in the process of predicting the elastic moduli of structural layers and mechanical responses,which indicates that the prediction results have great consistency with finite element simulation results.This paper provides a novel method for fast and accurate prediction of pavement mechanical responses under instantaneous large impact load using partial structural parameters of pavements,and has application potential in non-destructive evaluation of pavement structure.展开更多
基金the Natural Science Foundation of China(Grant No:22309180)Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No:XDB0600000,XDB0600400)+3 种基金Liaoning Binhai Laboratory,(Grant No:LILBLB-2023-04)Dalian Revitalization Talents Program(Grant No:2022RG01)Youth Science and Technology Foundation of Dalian(Grant No:2023RQ015)the University of Waterloo.
文摘Zinc-air batteries(ZABs)are promising energy storage systems because of high theoretical energy density,safety,low cost,and abundance of zinc.However,the slow multi-step reaction of oxygen and heavy reliance on noble-metal catalysts hinder the practical applications of ZABs.Therefore,feasible and advanced non-noble-metal elec-trocatalysts for air cathodes need to be identified to promote the oxygen catalytic reaction.In this review,we initially introduced the advancement of ZABs in the past two decades and provided an overview of key developments in this field.Then,we discussed the work-ing mechanism and the design of bifunctional electrocatalysts from the perspective of morphology design,crystal structure tuning,interface strategy,and atomic engineering.We also included theoretical studies,machine learning,and advanced characterization technologies to provide a comprehensive understanding of the structure-performance relationship of electrocatalysts and the reaction pathways of the oxygen redox reactions.Finally,we discussed the challenges and prospects related to designing advanced non-noble-metal bifunctional electrocatalysts for ZABs.
基金supported by the National Natural Science Foundation of China(11201324)the Fok Ying Tuny Education Foundation(141114)the Sichuan Technology Program(2022ZYD0011,2022NFSC1852).
文摘For a general normed vector space,a special optimal value function called a maximal time function is considered.This covers the farthest distance function as a special case,and has a close relationship with the smallest enclosing ball problem.Some properties of the maximal time function are proven,including the convexity,the lower semicontinuity,and the exact characterizations of its subdifferential formulas.
基金funded by the Shenzhen Science and Technology Program (JCYJ20230807112007014)Shenzhen Key Medical Discipline Construction Fund (SZXK046)。
文摘BACKGROUND:We aimed to observe the dynamic changes in glucose metabolic reprogrammingrelated parameters and their ability to predict neurological prognosis and all-cause mortality in cardiac arrest patients after the restoration of spontaneous circulation(ROSC).METHODS:Adult cardiac arrest patients after ROSC who were admitted to the emergency or cardiac intensive care unit of the First Aflliated Hospital of Dalian Medical University from August 1,2017,to May 30,2021,were enrolled.According to 28-day survival,the patients were divided into a non-survival group(n=82) and a survival group(n=38).Healthy adult volunteers(n=40) of similar ages and sexes were selected as controls.The serum levels of glucose metabolic reprogrammingrelated parameters(lactate dehydrogenase [LDH],lactate and pyruvate),neuron-specific enolase(NSE) and interleukin 6(IL-6) were measured on days 1,3,and 7 after ROSC.The Acute Physiology and Chronic Health Evaluation II(APACHE II) score and Sequential Organ Failure Assessment(SOFA) score were calculated.The Cerebral Performance Category(CPC) score was recorded on day 28 after ROSC.RESULTS:Following ROSC,the serum LDH(607.0 U/L vs.286.5 U/L),lactate(5.0 mmol/L vs.2.0 mmol/L),pyruvate(178.0 μmol/L vs.70.9 μmol/L),and lactate/pyruvate ratio(34.1 vs.22.1) significantly increased and were higher in the non-survivors than in the survivors on admission(all P<0.05).Moreover,the serum LDH,pyruvate,IL-6,APACHE II score,and SOFA score on days 1,3 and 7 after ROSC were significantly associated with 28-day poor neurological prognosis and 28-day all-cause mortality(all P<0.05).The serum LDH concentration on day 1 after ROSC had an area under the receiver operating characteristic curve(AUC) of 0.904 [95% confidence interval [95% CI]:0.851–0.957]) with 96.8% specificity for predicting 28-day neurological prognosis and an AUC of 0.950(95% CI:0.911–0.989) with 94.7% specificity for predicting 28-day all-cause mortality,which was the highest among the glucose metabolic reprogramming-related parameters tested.CONCLUSION:Serum parameters related to glucose metabolic reprogramming were significantly increased after ROSC.Increased serum LDH and pyruvate levels,and lactate/pyruvate ratio may be associated with 28-day poor neurological prognosis and all-cause mortality after ROSC,and the predictive eflcacy of LDH during the first week was superior to others.
基金Shenzhen Science and Technology Program(JCYJ20230807112007014,to PG)Shenzhen Key Medical Discipline Construction Fund(SZXK046,to PG).
文摘Anti-glomerular basement membrane(anti-GBM)disease is a rare small vessel vasculitis representing the most aggressive form of autoimmune glomerulonephritis.[1,2]Its overall incidence ranges from 0.60 to 1.79 per million population annually.[1]Anti-GBM disease is mediated by abnormal anti-GBM antibody production,which mainly targets GBM and thus contributes to rapid progressive glomerulonephritis with a distinctive pattern of diffuse crescentic formation in the glomeruli.
文摘目的:对比分析双眼三焦点IOL(AT LISA tri 839MP IOL)植入与一眼植入AT LISA tri 839MP IOL而另一眼植入非球面单焦点IOL患者术后视觉相关生活质量。方法:前瞻性临床研究。收集2018-05/2019-08在我院行白内障超声乳化联合三焦点AT LISA tri 839MP IOL植入的患者45例,按是否双眼植入AT LISA tri 839MP IOL分为两组,双眼植入者24例纳入双眼三焦点组;一眼植入AT LISA tri 839MP IOL而另一眼植入非球面单焦点IOL者21例纳入单眼三焦点组。术后3mo,检测两组患者裸眼视力及等效球镜度,并通过中国版视功能指数量表(VF-14-CN)评价视觉相关生活质量,评估日常生活脱镜率及满意度。结果:术后3mo,双眼三焦点组和单眼三焦点组患者双眼裸眼远、中、近视力均无明显差异(P>0.05),两组患者VF-14-CN问卷得分(96.2±0.50、92.43±1.32分)、日常生活脱镜率(96%、90%)及患者主观满意度(96%、95%)均无差异(P>0.05)。结论:双眼植入AT LISA tri 839MP IOL和一眼植入AT LISA tri 839MP IOL而另一眼植入非球面单焦点IOL的患者术后均具有良好的双眼裸眼远、中、近视力,术后视觉相关生活质量、脱镜率、满意度无明显差异。对一眼不适合植入三焦点IOL或既往一眼已植入非球面单焦点IOL的患者,可考虑另一眼行三焦点IOL植入以满足患者双眼全程视力的要求。
文摘Soil microbial biomass is an important indicator to measure the dynamic changes of soil carbon pool.It is of great signifi cance to understand the dynamics of soil microbial biomass in plantation for rational management and cultivation of plantation.In order to explore the temporal dynamics and infl uencing factors of soil microbial biomass of Keteleeria fortunei var.cyclolepis at diff erent stand ages,the plantation of diff erent ages(young forest,5 years;middle-aged forest,22 years;mature forest,40 years)at the Guangxi Daguishan forest station of China were studied to examine the seasonal variation of their microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN)by chloroform fumigation extraction method.It was found that among the forests of diff erent age,MBC and MBN diff ered signifi cantly in the 0–10 cm soil layer,and MBN diff ered signifi cantly in the 10–20 cm soil layer,but there was no signifi cant diff erence in MBC for the 10–20 cm soil layer or in either MBC or MBN for the 20–40 cm soil layer.With increasing maturity of the forest,MBC gradually decreased in the 0–10 cm soil layer and increased fi rstly and then decreased in the 10–20 cm and 20–40 cm soil layers,and MBN increased fi rstly and then decreased in all three soil layers.As the soil depth increased,both MBC and MBN gradually decreased for all three forests.The MBC and MBN basically had the same seasonal variation in all three soil layers of all three forests,i.e.,high in the summer and low in the winter.Correlation analysis showed that MBC was signifi cantly positively correlated with soil organic matter,total nitrogen,and soil moisture,whereas MBN was signifi cantly positively correlated with soil total nitrogen.It showed that soil moisture content was the main factor determining the variation of soil microbial biomass by Redundancy analysis.The results showed that the soil properties changed continuously as the young forest grew into the middle-aged forest,which increased soil microbial biomass and enriched the soil nutrients.However,the soil microbial biomass declined as the middle-age forest continued to grow,and the soil nutrients were reduced in the mature forest.
基金supported in part by NSAF(No.U1830201)in part by the State Administration of Science,Technology and Industry for Nation Defense of China,Technology Foundation Project(No.JSJL2019212B006)+1 种基金in part by the Academy Innovation Funder(No.CX2020038)in part by the National Defense Basic Scientific Research Program(No.2018212C015)。
文摘A dual-frequency(105/140 GHz)MW-level continuous-wave gyrotron was developed for fusion application at Institute of Applied Electronics,China Academy of Engineering Physics.This gyrotron employs a cylindrical cavity working in the TE18,7 mode at 105 GHz and the TE24,9 mode at 140 GHz.A triode magnetron injection gun and a built-in quasi-optical mode converter were designed to operate at these two frequencies.For the proof-test phase,the gyrotron was equipped with a single-disk boron nitride window to achieve radio frequency output with a power of~500 k W for a short-pulse duration.In the preliminary short-pulse proof-test in the first quarter of2021,the dual-frequency gyrotron achieved output powers of 300 k W at 105 GHz and 540 k W at140 GHz,respectively,under 5 Hz 1 ms continuous pulse-burst operations.Power upgrade and pulse-width extension were hampered by the limitation of the high-voltage power supply and output window.This gyrotron design was preliminarily validated.
基金This work was supported by the Fundamental Research Funds for Guangxi Zhuang Autonomous Region Forestry Research Institute(No.Linke 201809)Guangxi Forestry Science and Technology Promotion Demonstration Project(No.26 Guilin Research 2021).
文摘Liquidambar formosana Hance is an attractive landscape tree species because its leaves gradually change from green to red,purple or orange in autumn.In this study,the red variety of L.formosana was used to establish a quantitative model of leaf color.Physiological changes in leaf color,pigment levels,enzyme activity,photosynthetic fluorescence characteristics and chloroplast ultrastructure were monitored.The relationship between leaf color and physiological structure indices was quantitatively analyzed to systematically explore the mechanisms behind leaf color.Our data showed that with a decrease in external temperatures,chloroplast numbers and sizes gradually decreased,thylakoid membranes became distorted,and chlorophyll synthesis was blocked and gradually decreased.As a result,chloroplast membranes could not be biosynthesized normally;net photosynthesis,maximum and actual photochemical efficiency,and rate of electron transfer decreased rapidly.Excess light energy caused leaf photoinhibition.With intensification of photoinhibition,leaves protected themselves using two mechanisms.In the first,anthocyanin synthesis was promoted by increasing chalcone isomerase and flavonoid glycosyltransferase activities and soluble sugar content so as to increase anthocyanin to filter light and eliminate reactive oxygen species to reduce photoinhibition.In the second,excessive light energy was consumed in the form of heat energy by increasing the non-photochemical quenching coefficient.These processes tuned the leaves red.
文摘The widespread use of gastrointestinal bleeding prophylaxis in critically ill patients was one of the most controversial issues. Since few studies reported the incidence of gastrointestinal bleeding in mechanically ventilated patients, this study aimed to identify the incidence and risk factors related to gastrointestinal bleeding in patients undergoing mechanical ventilation for more than 48 hours. A total of 283 IOU patients who had received mechanical ventilation for longer than 48 hours at a provincial hospital affiliated to Shandong University from January 1,2007 to December 31, 2009 were analyzed retrospectively. Those were excluded from the study if they had a history of gastrointestinal bleeding or ulceration, recent gastrointestinal surgery, brain death and active bleeding from the nose or throat. Demographic data of the patients included patient age, diagnosis on admission, duration of ICU stay, duration of ventilation, patterns and parameters of ventilation, ICU mortality, APACHE II score, multiple organ dysfunction, and indexes of biochemistry, kidney function, liver function and coagulation function. Risk factors of gastrointestinal bleeding were analyzed by univariate analysis and multiple logistic regression analysis. In the 242 patients who were given mechanical ventilation longer than 48 hours, the incidence of gastrointestinal bleeding was 46.7%. The bleeding in 3.3% of the patients was clinically significant. Significant risk factors were peak inspiratory pressure 〉30cmH2O, renal failure, liver failure, PLT count〈50xl09/L and prolonged APTT. Enteral nutrition had a beneficial effect on gastrointestinal bleeding. However, the multiple logistic regression analysis revealed that the independent risk factors of gastrointestinal bleeding were as follows： high pressure ventilator setting 〉 30cmH2O（RR=3.478, 95%CI=2.208-10.733）, renal failure（RR=1 .687, 95%CI=1.098-3.482）, PLT count〈50×10^9/L （RR=3.762, 95%CI=2.346-14.685）, and prolonged APTT（RR=5.368, 95%CI=2.487-11.266）. Enteral nutrition（RR=0.436, 95%CI= 0.346-0.764） was the independent protective factor. The incidence of gastrointestinal bleeding was high in the patients who received mechanical ventilation, and bleeding usually occurred within the first 48 hours. High pressure ventilator setting, renal failure, decreased PLT count and prolonged APTT were the significant risk factors of gastrointestinal bleeding. However, enteral nutrition was the independent protective factor.
基金Project supported by the Information Program of the Chinese Academy of Sciences(Grant No.XXH13506-202)
文摘Topological materials have novel properties both in their bulk and boundaries,thereby attracting a wide interest in the theoretical and experimental communities.The recent development of the topological quantum chemistry and symmetrybased indicator theory in this field has significantly simplified the procedure for determining the topological properties of nonmagnetic crystalline materials.Accordingly,a large number of new topological materials have been found by scanning large crystal databases.This study provides details on the algorithm used in the Catalogue of Topological Electronic Materials.Moreover,based on the algorithm,we develop an automatic package named SymTopo,which calculates the symmetry representations of any given nonmagnetic crystalline material and predicts its topological properties.This package may facilitate the discovery of more topological materials in the future.
文摘In the paper, we illustrate the importance of the concept of mobile network computer from a technological perspective. Because of the usefulness of mobile network computers, with the growth of the Internet of things, mobile network computers may include not only TV box audio-visual equipment, wireless household appliances, and mobile communication equipment, but may also include devices such as intelligent foot rings, smart watches, smart glasses, smart shoes and smart coats. Considering the different types of networks, e.g. IP multimedia Subsystem(IMS), we explain why some network elements are inaccurate and misleading from a technological perspective. We aim to popularize the concept of mobile network computers for its accuracy and importance, which better define modern mobile terminals and reflects the nature of multiple mobile terminals based on the structure of their integrated computers and the capabilities of processing multimedia. In the computer and Internet age, network computers and mobile network computers are the main terminals of fixed and mobile networks, respectively. Therefore, based on the concept of mobile network computers, we discuss the future of information society.
基金Project supported in part by the National Natural Science Foundation of China(Grant No.12075168)the Fund from the Science and Technology Commission of Shanghai Municipality(Grant No.21JC1405600)。
文摘The layered pavements usually exhibit complicated mechanical properties with the effect of complex material properties under external environment.In some cases,such as launching missiles or rockets,layered pavements are required to bear large impulse load.However,traditional methods cannot non-destructively and quickly detect the internal structural of pavements.Thus,accurate and fast prediction of the mechanical properties of layered pavements is of great importance and necessity.In recent years,machine learning has shown great superiority in solving nonlinear problems.In this work,we present a method of predicting the maximum deflection and damage factor of layered pavements under instantaneous large impact based on random forest regression with the deflection basin parameters obtained from falling weight deflection testing.The regression coefficient R^(2)of testing datasets are above 0.94 in the process of predicting the elastic moduli of structural layers and mechanical responses,which indicates that the prediction results have great consistency with finite element simulation results.This paper provides a novel method for fast and accurate prediction of pavement mechanical responses under instantaneous large impact load using partial structural parameters of pavements,and has application potential in non-destructive evaluation of pavement structure.
