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Influence of vapor pressure deficit on vegetation growth in China
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作者 LI Chuanhua ZHANG Liang +3 位作者 WANG Hongjie PENG Lixiao YIN Peng MIAO Peidong 《Journal of Arid Land》 SCIE CSCD 2024年第6期779-797,共19页
Vapor pressure deficit(VPD)plays a crucial role in determining plant physiological functions and exerts a substantial influence on vegetation,second only to carbon dioxide(CO_(2)).As a robust indicator of atmospheric ... Vapor pressure deficit(VPD)plays a crucial role in determining plant physiological functions and exerts a substantial influence on vegetation,second only to carbon dioxide(CO_(2)).As a robust indicator of atmospheric water demand,VPD has implications for global water resources,and its significance extends to the structure and functioning of ecosystems.However,the influence of VPD on vegetation growth under climate change remains unclear in China.This study employed empirical equations to estimate the VPD in China from 2000 to 2020 based on meteorological reanalysis data of the Climatic Research Unit(CRU)Time-Series version 4.06(TS4.06)and European Centre for Medium-Range Weather Forecasts(ECMWF)Reanalysis 5(ERA-5).Vegetation growth status was characterized using three vegetation indices,namely gross primary productivity(GPP),leaf area index(LAI),and near-infrared reflectance of vegetation(NIRv).The spatiotemporal dynamics of VPD and vegetation indices were analyzed using the Theil-Sen median trend analysis and Mann-Kendall test.Furthermore,the influence of VPD on vegetation growth and its relative contribution were assessed using a multiple linear regression model.The results indicated an overall negative correlation between VPD and vegetation indices.Three VPD intervals for the correlations between VPD and vegetation indices were identified:a significant positive correlation at VPD below 4.820 hPa,a significant negative correlation at VPD within 4.820–9.000 hPa,and a notable weakening of negative correlation at VPD above 9.000 hPa.VPD exhibited a pronounced negative impact on vegetation growth,surpassing those of temperature,precipitation,and solar radiation in absolute magnitude.CO_(2) contributed most positively to vegetation growth,with VPD offsetting approximately 30.00%of the positive effect of CO_(2).As the rise of VPD decelerated,its relative contribution to vegetation growth diminished.Additionally,the intensification of spatial variations in temperature and precipitation accentuated the spatial heterogeneity in the impact of VPD on vegetation growth in China.This research provides a theoretical foundation for addressing climate change in China,especially regarding the challenges posed by increasing VPD. 展开更多
关键词 vapor pressure deficit(VPD) near-infrared reflectance of vegetation(NIRv) leaf area index(LAI) gross primary productivity(GPP) Climatic Research Unit(CRU)Time-Series version 4.06(TS4.06) European Centre for Medium-Range Weather Forecasts(ECMWF)Reanalysis 5(ERA-5) climate change
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Correlation between blood pressure changes and AMS, sleeping quality and exercise upon high-altitude exposure in young Chinese men 被引量:6
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作者 Yang Liu Ji-Hang Zhang +6 位作者 Xu-Bin Gao Xiao-Jing Wu Jie Yu Jian-Fei Chen Shi-Zhu Bian Xiao-Han Ding Lan Huang 《Journal of Medical Colleges of PLA(China)》 CAS 2014年第2期89-97,共9页
Background: Excessive elevation of arterial blood pressure(BP) at high altitude can be detrimental to our health due to acute mountain sickness(AMS) or some AMS symptoms. This prospective and observational study aimed... Background: Excessive elevation of arterial blood pressure(BP) at high altitude can be detrimental to our health due to acute mountain sickness(AMS) or some AMS symptoms. This prospective and observational study aimed to elucidate blood pressure changes induced by exposure to high-altitude hypoxia and the relationships of these changes with AMS prevalence, AMS severity, sleep quality and exercise condition in healthy young men.Methods: A prospective observational study was performed in 931 male young adults exposed to high altitude at 3,700 m(Lhasa) from low altitude(LA, 500 m). Blood pressure measurement and AMS symptom questionnaires were performed at LA and on day 1, 3, 5, and 7 of exposure to high altitude. Lake Louise criteria were used to diagnose AMS. Likewise, the Athens Insomnia Scale(AIS) and the Epworth Sleepiness Scale(ESS) were filled out at LA and on day 1, 3, and 7 of exposure to high altitude.Results: After acute exposure to 3,700 m, diastolic blood pressure(DBP) and mean arterial blood pressure(MABP) rose gradually and continually(P<0.05). Analysis showed a relationship with AMS for only MABP(P<0.05) but not for SBP and DBP(P>0.05). Poor sleeping quality was generally associated with higher SBP or DBP at high altitude, although inconsistent results were obtained at different time(P<0.05). SBP and Pulse BP increased noticeably after high-altitude exercise(P<0.05).Conclusions: Our data demonstrate notable blood pressure changes under exposure to different high-altitude conditions: 1) BP increased over time. 2) Higher BP generally accompanied poor sleeping quality and higher incidence of AMS. 3) SBP and Pulse BP were higher after high-altitude exercise. Therefore, we should put more effort into monitoring BP after exposure to high altitude in order to guard against excessive increases in BP. 展开更多
关键词 ARTERIAL blood pressure changes high ALTITUDE acut
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Associations of soybean products intake with blood pressure changes and hypertension incidence: the China-PAR project 被引量:3
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作者 Jia-Liu WEI Xin-Yan WANG +9 位作者 Fang-Chao LIU Ji-Chun CHEN Jie CAO Jian-Xin LI Dong-Sheng HU Chong SHEN Fang-Hong LU Ying-Xin ZHAO Jian-Feng HUANG Xiang-Feng LU 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2020年第7期384-392,共9页
Background The relationships between dietary intake of soybean products and incident hypertension were still uncertain.This study aimed to illustrate the associations between intake of soybean products with risks of i... Background The relationships between dietary intake of soybean products and incident hypertension were still uncertain.This study aimed to illustrate the associations between intake of soybean products with risks of incident hypertension and longitudinal changes of blood pressure in a prospective cohort study.Methods We included 67,499 general Chinese adults from the Project of Prediction for Atherosclerosis Cardiovascular Disease Risk in China(China-PAR).Information about soybean products consumption was collected by standardized questionnaires,and study participants were categorized into the ideal(≥125 g/day)or non-ideal(<125 g/day)group.Hazard ratios(HRs)and corresponding 95%confidence intervals(95%CIs)for incident hypertension were calculated using Cox proportional hazard models.Among participants with repeated measures of blood pressure,generalized linear models were used to examine the relationships between soybean products consumption and blood pressure changes.Results During a median follow-up of 7.4 years,compared with participants who consumed<125 g of soybean products per day,multivariable adjusted HR for those in the ideal group was 0.73(0.67-0.80).This inverse association remained robust across most subgroups while significant interactions were tested between soybean products intake and age,sex,urbanization and geographic region(P values for interaction<0.05).The mean systolic and diastolic blood pressure levels were 1.05(0.71-1.39)mmHg and 0.44(0.22-0.66)mmHg lower among participants in the ideal group than those in the non-ideal group.Conclusions Our study showed that intake of soybean products might reduce the long-term blood pressure levels and hypertension incidence among Chinese population,which has important public health implications for primary prevention of hypertension. 展开更多
关键词 Blood pressure changes Chinese population Cohort study HYPERTENSION Soybean products
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Application of Negative Pressure Manual Dressing Change Combined with Mupirocin Ointment in the Treatment of a Case of a Patient with Cirrhosis Complicated with Deep Thigh Abscess 被引量:1
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作者 Yingying Meng Wali Lukman Ahmed Jian Luo 《Journal of Biosciences and Medicines》 2020年第5期113-121,共9页
Objective: To explore the treatment and nursing characteristics for pressure injury on the inside of the thigh caused by forced posture in patients with cirrhosis and diabetes mellitus. Methods: A patient with cirrhos... Objective: To explore the treatment and nursing characteristics for pressure injury on the inside of the thigh caused by forced posture in patients with cirrhosis and diabetes mellitus. Methods: A patient with cirrhosis and diabetes mellitus complicated with abscess of right inner thigh pressure injury was selected as the study object, who was admitted to Xuzhou Medical University Hospital on June 29, 2019. The analysis of the clinical diagnosis, treatment and nursing process were applied to explore the prognosis of the patient with cirrhosis and diabetes mellitus complicated with deep abscess of the thigh. Results: The traditional treatment including incision and drainage was not allowed, as the general treatment was not effective for the patients with cirrhosis and diabetes mellitus complicated with deep abscess in the inner thigh. After 8 days of negative pressure manual dressing change combined with mupirocin ointment treatment, the local skin condition returned to normal. Conclusion: After literature search, it was found that the above-mentioned cirrhosis combined with diabetes and deep abscess cases in the inner thigh were rare clinically. When the traditional treatment of incision and drainage is limited, negative pressure manual dressing change combined with antibiotics is an effective method, which is worthy of clinical application and promotion. 展开更多
关键词 CIRRHOSIS Diabetes Mellitus pressure Injury DEEP Tissue ABSCESS Negative pressure DRESSING change
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Effect of change in large and fast solar wind dynamic pressure on geosynchronous magnetic field 被引量:1
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作者 Borodkova 刘静波 +3 位作者 黄朝晖 Zastenker G N 王赤 Eiges P E 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第10期2458-2464,共7页
We present a comparison of changes in large and sharp solar wind dynamic pressure, observed by several spacecraft, with fast disturbances in the magnetospheric magnetic field, measured by the geosynchronous satellites... We present a comparison of changes in large and sharp solar wind dynamic pressure, observed by several spacecraft, with fast disturbances in the magnetospheric magnetic field, measured by the geosynchronous satellites. More than 260 changes in solar wind pressure during the period 1996-2003 are selected for this study. Large statistics show that an increase (a decrease) in dynamic pressure always results in an increase (a decrease) in the magnitude of geosynchronous magnetic field. The amplitude of response to the geomagnetic field strongly depends on the location of observer relative to the noon meridian, the value of pressure before disturbance, and the change in amplitude of pressure. 展开更多
关键词 solar wind dynamic pressure changes geosynchronous magnetic field
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Mechanical effects of circular liquid inclusions inside soft matrix:role of internal pressure change and surface tension 被引量:1
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作者 Lei ZHANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2021年第4期501-510,共10页
The mechanical effects of dilute liquid inclusions on the solid-liquid composite are explored,based on an analytical circular inclusion model incorporating the internal pressure change of the liquid and the surface te... The mechanical effects of dilute liquid inclusions on the solid-liquid composite are explored,based on an analytical circular inclusion model incorporating the internal pressure change of the liquid and the surface tension of the interface.Several simple explicit dependences of the stress field and effective stiffness on the bulk modulus and the size of the liquid,the surface tension,and Poisson’s ratio of the matrix are derived.The results show that the stresses in the matrix are reduced,and the stiffness of the solid-liquid composite is enhanced with the consideration of either the surface tension or the internal pressure change.Particularly,the effective Young’s modulus predicted by the present model for either soft or stiff matrices agrees well with the known experimental data.In addition,according to the theoretical results,it is possible to stiffen a soft solid by pressured gas with the presence of the surface tension of the solid-gas interface. 展开更多
关键词 liquid inclusion stress field effective stiffness surface tension internal pressure change
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Modeling the Pressure Distribution and the Changes of Water Level around the Offshore Platforms Exposed to Waves, Using the Numerical Model of Flow 3D 被引量:1
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作者 Milad Rashidinasab Mehdi Behdarvandi Askar 《Computational Water, Energy, and Environmental Engineering》 2017年第1期97-106,共10页
The humans’ need to use the oceans for exploration and extraction of oil has led to the development of engineering science in the field of offshore structures. Since it’s important to examine the offshore structures... The humans’ need to use the oceans for exploration and extraction of oil has led to the development of engineering science in the field of offshore structures. Since it’s important to examine the offshore structures from different aspects and perspectives, we would have to evaluate many different parameters about them. So categorizing these parameters can help to perform their related analysis with more accuracy and more details. Due to the efficient force it exerts on the structure, the pressure distribution around every marine or hydraulic structure has a significant importance, and it even accounts for one of the dominant issues in designing and building of such structures. In the present study, an oil platform located in Phase 15 of South Pars oil fields, located in the Persian Gulf waters, has been analyzed using the FLOW 3D software. The outputs indicate that the pressure of water is distributed almost hydrostatically with the depth, and its maximum reaches 0.6 MPa at the bottom. 展开更多
关键词 pressure Distribution OFFSHORE PLATFORMS changeS of Water Level MODELING
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Visualizing Relationships between Drivers of Environmental Change and Pressures on Land-Based Ecosystems 被引量:1
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作者 Jason Jabbour Carol Hunsberger 《Natural Resources》 2014年第4期146-160,共15页
The pursuit of human needs and demands is placing more pressure on land resources than ever before. The challenge of feeding 7 billion people is increasingly competing with rising demands for materials and biofuels. D... The pursuit of human needs and demands is placing more pressure on land resources than ever before. The challenge of feeding 7 billion people is increasingly competing with rising demands for materials and biofuels. Deforestation and land degradation are among the pressing outcomes of these trends. Drivers of environmental change—including population growth, economic activity, consumption, urbanization, trade, conflict, and governance—clearly play a role in aggravating or mitigating these pressures on land. Despite advances in understanding causality in complex systems, navigating the interactions between these drivers remains a major challenge. This paper analyzes and visualizes the relationships between multiple, interacting drivers of environmental change and specific pressures on land-based ecosystems. Drawing on experience from the development of the Drivers and Land chapters of the UN Environment Programme’s Fifth Global Environment Outlook report (GEO-5), we use a series of Kiviat diagrams to illustrate the relative influence of key drivers on selected pressures on land. When individual diagrams are overlaid, patterns of influence emerge that can provide insight into where policy responses might best be targeted. We propose that, subject to some limitations, the Kiviat exercise can provide an accessible and potentially valuable “knowledge-intermediary” tool to help link science-based information to policy action. 展开更多
关键词 DRIVERS ENVIRONMENTAL pressure LAND Use change Integrated Assessment Science-Policy
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Disadvantage Pressure Changes on the Decline of Water Quality in Water Distribution Systems 被引量:1
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作者 Hossein Shamsaei Othman Jaafar Noor Ezlin Ahmad Basri 《Engineering(科研)》 2013年第1期97-105,共9页
Systems that have big transmission line may have problem on changes of pressure in the distribution system. Because pressure rate changes have been too much between water treatment plant and dead ends in distribution ... Systems that have big transmission line may have problem on changes of pressure in the distribution system. Because pressure rate changes have been too much between water treatment plant and dead ends in distribution system. This study is to analyze the effects pressure changes on the water quality in water distribution systems. It is located in south west of Ahwaz in IRAN. Ahwaz has five water treatment plants. In Ahwaz, two methods will be utilized. In the first method, samples will be taken from different locations in other to examine the quality of water in the distribution systems and the other method involves the use of simulation of models EPANET. Based on the EPANET model analysis of the water distribution system of Ahwaz as shown in result above the systems has large transmission line and exten- sive networks. So, the distance travelled and residence times have been causing to increase bacterial growth (HPC), chlorine consumption and hydraulic change (pressure) in water distribution system in Ahwaz. Pressure has a reversed relationship with bacterial growth (HPC) and Pressure has a direct relationship with residual chlorine. Pressure change has been causing to increase chlorine consumption more. So, Kw hasn’t any relationship with pressure and bacterial growth (HPC). The result of pressure changes among others can decrease in chlorine content and hydraulic factors, because the systems may be extensive and thus possess complex networks and hangs in quantity cause pressure of flow. Hence hydraulic changes (pressure) could affect of water quality in the water distribution system. 展开更多
关键词 Residual CHLORINE Bacterial Growth (HPC) pressure changeS WATER Quality Kw and WATER Distribution System
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Granular pressure–temperature relation during regime change in a simple shear state
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作者 Hayley Shen 《Theoretical & Applied Mechanics Letters》 CAS 2013年第2期21-24,共4页
In a recent study, a regime chart was established for sheared granular systems. For a soft particle system under simple shear, the internal stress showed a range of rate dependency. As the particle concentration incre... In a recent study, a regime chart was established for sheared granular systems. For a soft particle system under simple shear, the internal stress showed a range of rate dependency. As the particle concentration increased, the system transitioned from a kinetic gas to a plastic solid. This transition was gradual for low stiffness systems but became more abrupt as the stiffness increased. In this study, the relationship between the granular temperature and pressure is investigated for the same system of particles. The granular temperature is defined as the average kinetic energy per unit volume and the pressure is defined as the trace of the stress tensor. It is found that this pressure-temperature (P-T) curve depicts a sharp turn when the system moves away from the kinetic gas regime. However, no signature is found in the P-T relationship in other regimes. 展开更多
关键词 granular materials regime change pressure TEMPERATURE
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Noncontact Monitoring of Relative Changes in Blood Pressure Using Microwave Radar Sensors
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作者 Satoshi Suzuki Guanghao Sun +2 位作者 Masaaki Hoshiga Kentaro Kotani Takafumi Asao 《Journal of Biomedical Science and Engineering》 2022年第1期51-65,共15页
This study aims to confirm whether noncontact monitoring of relative changes in blood pressure can be estimated using microwave radar sensors. First, an equation to estimate blood pressure was derived, after which, th... This study aims to confirm whether noncontact monitoring of relative changes in blood pressure can be estimated using microwave radar sensors. First, an equation to estimate blood pressure was derived, after which, the effectiveness of the estimation equation was confirmed using data obtained by a noncontact method while inducing variations in blood pressure. We considered that the Bramwell-Hill equation, which contains some parameters that directly indicate changes in blood pressure, would be an appropriate reference to construct an estimation equation for the noncontact method, because measurements using microwave radar sensors can measure minute scale motion on the skin surface induced by the pulsation of blood vessels. In order to estimate relative changes in blood pressure, we considered a simple equation including the pulse transit time (PTT), amplitude of signals and body dimensions as parameters. To verify the effectiveness of the equation for estimating changes in blood pressure, two experiments were conducted: a cycling task using an ergometer, which induces blood pressure fluctuations because of changes in cardiac output, and a task using the Valsalva maneuver, which induces blood pressure fluctuations because of changes in vascular resistance. The results obtained from the two experiments suggested that the proposed equation using microwave radar sensors can accurately estimate relative changes of blood pressure. In particular, relatively favorable results were obtained for the changes in blood pressure induced by the changes in cardiac volume. Although many issues remain, this method could be expected to contribute to the continuous evaluation of cardiac function while reducing the burden on patients. 展开更多
关键词 Microwave Radar Noncontact Monitoring Blood pressure Relative change Continuous Monitor
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Local and Time Changes over a 66-Year Period and Annual Relocation of Saudi Arabian Subtropical High Pressure
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作者 Hasan Lashkari Ali Akbar Matkan Zainab Mohammadi 《Open Journal of Geology》 2016年第9期1080-1095,共16页
Saudi Arabian subtropical high pressure is a major system affecting general circulation of the atmosphere of west Asia. Its annual relocation affects the relocation of other systems in the area, such as Mediterranean ... Saudi Arabian subtropical high pressure is a major system affecting general circulation of the atmosphere of west Asia. Its annual relocation affects the relocation of other systems in the area, such as Mediterranean cyclones, Sudanese low pressure areas, and west wind waves. This system is known to relocate to the south and north in response to outward solar relocation, but the reasons behind its eastern and western relocation have not been studied thoroughly. The present study examined 1000 and 850 HPa levels over the course of 66 years (1948-2015) to determine a pattern of latitudinal and longitudinal relocation of the system using synoptic maps. The research showed that, after 2008, high pressure latitudinal and longitudinal swings were larger than in previous years and the annual high pressure relocation was not in concord with the apparent motion of the sun. At the onset of autumnal moderation, the high pressure core was positioned to the north of Saudi Arabia (22° - 30° north latitude and 42° - 50° south longitude). Southern movement continued until the end of March, when the core again relocated to the north. These relocations first occurred slowly, but the northern relocation occurred very quickly from May to June, such that the core moved northward 22° to 30°. After June, the core did not relocate much until the end of September. After September, it relocated strongly south in all time periods. It was noted that high pressure over Saudi Arabia had two cores from June to September in some years;in others the high pressure core was in southwestern Iran and Iraq. In still others, a southwest to northeast high pressure tab entered Iran from the southwest (Khuzestan) and continued northward with a core forming in the northern Caspian Sea. 展开更多
关键词 Analysis Time and Local change Subtropical High pressure Saudi Arabia
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THE CURATIVE EFFECT OF HIGH EFFICIENCY HEMODIALYSIS AND THE GRADIENT CHANGE OF PLASMA OSMOTIC PRESSURE(Report of 27 Cases)
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《Chinese Journal of Biomedical Engineering(English Edition)》 1996年第1期25-29,共5页
THECURATIVEEFFECTOFHIGHEFFICIENCYHEMODIALYSISANDTHEGRADIENTCHANGEOFPLASMAOSMOTICPRESSURE(Reportof27Cases)Che... THECURATIVEEFFECTOFHIGHEFFICIENCYHEMODIALYSISANDTHEGRADIENTCHANGEOFPLASMAOSMOTICPRESSURE(Reportof27Cases)ChenHuaji(CentralHos... 展开更多
关键词 Report of 27 Cases THE CURATIVE EFFECT OF HIGH EFFICIENCY HEMODIALYSIS AND THE GRADIENT change OF PLASMA OSMOTIC pressure
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Hydraulic and volume change behaviors of compacted highly expansive soil under cyclic wetting and drying 被引量:3
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作者 Mohamed Farid Abbas Abdullah Ali Shaker Mosleh A.Al-Shamrani 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第2期486-499,共14页
The wide engineered application of compacted expansive soils necessitates understanding their behavior under field conditions.The results of this study demonstrate how seasonal climatic variation and stress and bounda... The wide engineered application of compacted expansive soils necessitates understanding their behavior under field conditions.The results of this study demonstrate how seasonal climatic variation and stress and boundary conditions individually or collectively influence the hydraulic and volume change behavior of compacted highly expansive soils.The cyclic wetting and drying(CWD)process was applied for two boundary conditions,i.e.constant stress(CS)and constant volume(CV),and for a wide range of axial stress states.The adopted CWD process affected the hydraulic and volume change behaviors of expansive soils,with the first cycle of wetting and drying being the most effective.The CWD process under CS conditions resulted in shrinkage accumulation and reduction in saturated hydraulic conductivity(k sat).On the other hand,CWD under CV conditions caused a reduction of swell pressure while has almost no impact on k sat.An elastic response to CWD was achieved after the third cycle for saturated hydraulic conductivity(k sat),the third to fourth cycle for the volume change potential under the CV conditions,and the fourth to fifth cycle for the volume change potential under the CS conditions.Finally,both swell pressure(s s)and saturated hydraulic conductivity(k sat)are not fundamental parameters of the expansive soil but rather depend on stress,boundary and wetting conditions. 展开更多
关键词 Expansive soils Hydraulic conductivity Volume change potential Cyclic wetting and drying(CWD) Swell pressure
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Space-time analysis of the changing patterns of population pressure on the ecological environment in China 被引量:1
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作者 Dongqi Sun Jinliang Jiang +2 位作者 Jianbin Xu Liang Zhou Yi Hu 《Chinese Journal of Population,Resources and Environment》 2015年第4期341-348,共8页
This paper examines the temporal change and spatial variation of population pressure on the ecological environment in China.We have collected sufficient data from the statistical yearbooks of 31 provincial administrat... This paper examines the temporal change and spatial variation of population pressure on the ecological environment in China.We have collected sufficient data from the statistical yearbooks of 31 provincial administrative areas in 1990,1995,2000,2005,and 2010.Using a geographic information system(GIS) and relevant models,we analyzed the trend of the population pressure on ecological environment and the change of the gravity center of ecological environment quality.We conclude that:(1) generally,population pressure on the ecological environment in China was becoming higher during1990-2010,especially in some areas where the population and environment were in serious imbalance and the ecological environment experienced severe pollution;(2) during a certain period,population pressure on the ecological environment was becoming lower in some areas,but the ecological environment was getting worse;(3) the areas with super-high population pressure on the ecological environment were Beijing,Tianjin,and Shanghai;(4) the gravity center of population pressure on the ecological environment and the center of ecological environment quality move differently during the study time period,but the general trend was similar- both of them were moving from west to east.Based on the analysis,this paper also provides some policy suggestions on the control of ecological environment quality. 展开更多
关键词 Chinese POPULATION ECO-ENVIRONMENT ECO-ENVIRONMENTAL pressure changING TREND SPACE-TIME analysis
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Climate change during the last glacial period on the southeast margin of Badain Jaran Desert, Northwest China 被引量:3
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作者 FAN Xiao-lu ZHANG Xin-yi TIAN Ming-zhong 《Journal of Mountain Science》 SCIE CSCD 2019年第10期2379-2388,共10页
Reconstruction of the desert paleoclimate is important to understand the mechanisms that triggered and/or enhanced climate change.Through optically stimulated luminescence(OSL)dating,grain size,magnetic susceptibility... Reconstruction of the desert paleoclimate is important to understand the mechanisms that triggered and/or enhanced climate change.Through optically stimulated luminescence(OSL)dating,grain size,magnetic susceptibility,X-ray powder diffraction(XRD)and geochemical indicators,we provide a welldated record of a sedimentary outcrop on the southeast margin of the Bardain Jaran Desert,Northwest China,during the last glacial period.Four Qz-OSL ages are obtained,41.0±3.4 ka,54.7±4.4 ka,59.5±5.0 ka and 66.8±5.8 ka,corresponding to the depths of 35 cm,70 cm,150 cm and 200 cm respectively.Indicators like grain size,clay content,magnetic susceptibility,XRD and geochemical index(e.g.Sr,Ba,Sr/Ca)jointly indicate abrupt climate changes at the depth of 35 cm(age,ca.41.0 ka)and200 cm(age,ca.67 ka).Namely,the 280 cm sedimentary outcrop perfectly records a warm wet climate stage,corresponding to the late Marine Isotope Stages(MIS)4 to the early MIS 3.Besides,there is a trend of grain size increase after around 40ka BP,which is most likely a signal of wind strength change.Our research supports that enhancing Siberian High pressure system during the late MIS 3played a key role in NW East Asia climate evolution. 展开更多
关键词 LAST GLACIAL period Bardain Jaran DESERT Climate change Siberian High pressure system XRD
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In vivo imaging of structural,metabolic and functional brain changes in glaucoma 被引量:3
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作者 Anisha Kasi Muneeb A.Faiq Kevin C.Chan 《Neural Regeneration Research》 SCIE CAS CSCD 2019年第3期446-449,共4页
Glaucoma, the world's leading cause of irreversible blindness, is a condition for which elevated intraocular pressure is currently the only modifiable risk factor. However, the disorder can continue to progress ev... Glaucoma, the world's leading cause of irreversible blindness, is a condition for which elevated intraocular pressure is currently the only modifiable risk factor. However, the disorder can continue to progress even at reduced intraocular pressure. This indicates additional key factors that contribute to the etiopathogenesis. There has been a growing amount of literature suggesting glaucoma as a neurodegenerative disease of the visual system. However, it remains debatable whether the observed pathophysiological conditions are causes or consequences. This review summarizes recent in vivo imaging studies that helped advance the understanding of early glaucoma involvements and disease progression in the brains of humans and experimental animal models. In particular, we focused on the non-invasive detection of early structural and functional brain changes before substantial clinical visual field loss in glaucoma patients; the eye-brain interactions across disease severity; the metabolic changes occurring in the brain's visual system in glaucoma; and, the widespread brain involvements beyond the visual pathway as well as the potential behavioral relevance. If the mechanisms of glaucomatous brain changes are reliably identified, novel neurotherapeutics that target parameters beyond intraocular pressure lowering can be the promise of the near future, which would lead to reduced prevalence of this irreversible but preventable disease. 展开更多
关键词 GLAUCOMA INTRAOCULAR pressure eye-brain-behavior relationship irreversible BLINDNESS magnetic resonance imaging METABOLIC BRAIN changeS sensitivity disease progression
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Land Use and Land Cover Change Analysis in Ajei Upland Watershed Community Forest, North West Region, Cameroon 被引量:1
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作者 Lucie Félicité Temgoua Gordon Ajonina Hans Berinyuy Woyu 《Journal of Geoscience and Environment Protection》 2018年第9期83-99,共17页
This study was carried out in Ajei upland watershed community forest in the North West Region of Cameroon with the aim to analyze spatial and temporal dynamics of land cover and land use from 1988 to 2018 and to ident... This study was carried out in Ajei upland watershed community forest in the North West Region of Cameroon with the aim to analyze spatial and temporal dynamics of land cover and land use from 1988 to 2018 and to identify and characterize the agents, drivers and pressures of this change. The databases used were made up of 3 Lands at satellite images (5 TM of 1988, 7ETM+ of 2003 and 8OLI of 2018). Field survey, interview and focus group discussion methods were used to identify the activities carried out by the local population and to determine agents, drivers and pressures of land use and land cover change. The Ajei community forest is consisted of four main land cover namely;dense vegetation, sparse or degraded vegetation, savanna and bare soil. Between 1988 and 2018, the proportions of dense vegetation and savanna decreased and that of bare soil and sparse vegetation increased. Analysis showed ongoing deforestation with forest cover loss of about 240 ha in 30 years. For the considered time periods 1988-2003 and 2003-2018, deforestation rates were 1.83% per year and 1.49% per year respectively, signifying on average 8 hectares of forest cover undergoing conversion each year. This lost results from the actions of farmers, cattle grazers and wood extractors who through farming, grazing and lumbering activities pressurize and convert the dense forest cover. Economic motives notably the need to increase household income from a frequent demand for farm and wood products in nearby markets represent the drivers of forest cover change. Controlling grazing activities notably in the dry season to check out the use of fires, community sensitization especially among cattle headmen on the importance of the community forest, reforestation activities through natural regeneration or tree planting are needed in the forest. 展开更多
关键词 LAND Use LAND COVER change Agents DRIVERS pressures
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Vapor pressure and thermochemical properties of ZrCl4 for ZrC coating of coated fuel particles 被引量:2
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作者 刘超 刘兵 +2 位作者 邵友林 李自强 唐春和 《中国有色金属学会会刊:英文版》 EI CSCD 2008年第3期728-732,共5页
Vapor pressure of zirconium tetrachloride(ZrCl4) under vacuum and an argon pressure of 1×105 Pa was measured. The thermochemical changes of ZrCl4 during evaporation were studied by thermogravimetry-differential t... Vapor pressure of zirconium tetrachloride(ZrCl4) under vacuum and an argon pressure of 1×105 Pa was measured. The thermochemical changes of ZrCl4 during evaporation were studied by thermogravimetry-differential thermal analysis(TG-DTA), X-ray diffractometry(XRD), scanning electron microscopy(SEM) and energy-dispersive X-ray(EDX) analysis. At the same temperature, vapor pressures of ZrCl4 under vacuum and an argon pressure of 1×105 Pa are approximately the same. The vapor pressure exceeds 1×105 Pa at 340 ℃, which is high enough for ZrC coating of coated fuel particles. ZrCl4 sample is hydrolyzed to some extent to give ZrO2 and HCl, which however, has little influence on vapor pressure of ZrCl4 at high temperature. No ZrCl3 and Cl2 are produced by decomposition of ZrCl4 during evaporation, which is confirmed by thermodynamic calculation. 展开更多
关键词 汽压 热化学转变 ZrC敷料 燃烧颗粒
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Fusion curves and thermodynamic properties of carbon tetrachloride,chloroform,bromoform and silicon tetrachloride at pressure up to 3500 MPa
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作者 朱荣娇 徐伟 +1 位作者 田宜灵 郝纪双 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第3期1088-1093,共6页
The fusion temperature as a function of pressure for carbon tetrachloride, chloroform, bromoform and silicon tetrachloride at pressures up to 3500MPa has been determined. The experimental data were fitted by the equat... The fusion temperature as a function of pressure for carbon tetrachloride, chloroform, bromoform and silicon tetrachloride at pressures up to 3500MPa has been determined. The experimental data were fitted by the equation Tfus=T0(1 + Δp/a1)^a2 exp(-a3Δp) and the changes of the maolar enthalpy and molar internal energy on fusion were calculated using the parameters of the fitted equation. Comparisons with the data from the literature show that the experimental data, parameters of fitted equations, changes of the molar enthalpy and molar internal energy are reliable. 展开更多
关键词 fusion curve molar entropy change molar internal energy change high pressure
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