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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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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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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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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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Effect of ambient wind on pressure wave generated by high-speed train entering a tunnel 被引量:7
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作者 ZHOU Xi-sai LIU Tang-hong +2 位作者 CHEN Zheng-wei ZOU Xiang LIU Dong-run 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第6期1465-1475,共11页
Using three-dimensional, unsteady N-S equations and k-ε turbulence model, the effect of ambient wind on the pressure wave generated by a high-speed train entering a tunnel was studied via numerical simulation. Pressu... Using three-dimensional, unsteady N-S equations and k-ε turbulence model, the effect of ambient wind on the pressure wave generated by a high-speed train entering a tunnel was studied via numerical simulation. Pressure changes of the train surface and tunnel wall were obtained as well as the flow field around the train. Results show that when the train runs downwind, the pressure change is smaller than that generated when there is no wind. When the train runs upwind, the pressure change is larger. The pressure change is more sensitive in the upwind condition than in the downwind condition. Compared with no wind condition, when the wind velocity is 10 m/s and 30 m/s, the pressure amplitude on the train head is reduced by 2.8% and 10.5%, respectively. The wall pressure amplitude at 400 m away from the tunnel entrance is reduced by 2.4% and 13.5%, respectively. When the wind velocity is-10 m/s and-30 m/s, the pressure amplitude on the train head increases by 3.0% and 17.7%, respectively. The wall pressure amplitude at 400 m away from the tunnel entrance increases by 3.6% and 18.6%, respectively. The pressure waveform slightly changes under ambient wind due to the influence of ambient wind on the pressure wave propagation speed. 展开更多
关键词 HIGH-SPEED train AMBIENT WIND pressure wave TUNNEL
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Exercise training in the management of patients with resistant hypertension 被引量:6
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作者 Fernando Ribeiro Rui Costa José Mesquita-Bastos 《World Journal of Cardiology》 CAS 2015年第2期47-51,共5页
Hypertension is a very prevalent risk factor for cardiovascular disease. The prevalence of resistant hypertension, i.e., uncontrolled hypertension with 3 or more antihypertensive agents including 1 diuretic, is betwee... Hypertension is a very prevalent risk factor for cardiovascular disease. The prevalence of resistant hypertension, i.e., uncontrolled hypertension with 3 or more antihypertensive agents including 1 diuretic, is between 5% and 30% in the hypertensive population. The causes of resistant hypertension are multifactorial and include behavioral and biological factors, such as nonadherence to pharmacological treatment. All current treatment guidelines highlight the positive role of physical exercise as a non-pharmacological tool in the treatment of hypertension. This paper draws attention to the possible role of physical exercise as an adjunct non-pharmacological tool in the management of resistant hypertension. A few studies have investigated it, employing different methodologies, and taken together they have shown promising results. In summary, the available evidence suggests that aerobic physical exercise could be a valuable addition to the optimal pharmacological treatment of patients with resistant hypertension. 展开更多
关键词 EXERCISE training RESISTANT HYPERTENSION BLOOD pressure NON-PHARMACOLOGICAL CARDIOVASCULAR disease
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Pressure waves acting on wall of a tunnel and their impact on the tunnel's structural safety 被引量:5
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作者 LIU Tang-hong WANG Lei +3 位作者 LI Li YANG Fan CHEN Zheng-wei LIU Hong-kang 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第10期3223-3237,共15页
The transient pressures induced by trains passing through a tunnel and their impact on the structural safety of the tunnel lining were numerically analyzed.The results show that the pressure change increases rapidly a... The transient pressures induced by trains passing through a tunnel and their impact on the structural safety of the tunnel lining were numerically analyzed.The results show that the pressure change increases rapidly along the tunnel length,and the maximum value is observed at around 200 m from the entrance,while the maximum pressure amplitude is detected at 250 m from the entrance when two trains meeting in a double-track tunnel.The maximum peak pressure on the tunnel induced by a train passing through a 70 m^(2) single-track tunnel,100 m^(2) double-track tunnel and two trains meeting in the 100 m^(2) double-track tunnel at 350 km/h,are−4544 Pa,−3137 Pa and−5909 Pa,respectively.The aerodynamic pressure induced axial forces acting on the tunnel lining are only 8%,5%and 9%,respectively,of those generated by the earth pressure.It seems that the aerodynamic loads exert little underlying influence on the static strength safety of the tunnel lining providing that the existing cracks and defects are not considered. 展开更多
关键词 high-speed train TUNNEL pressure change tunnel lining structural safety
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Influence of enlarged section parameters on pressure transients of high-speed train passing through a tunnel 被引量:12
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作者 WANG Tian-tian LEE Chun-hian YANG Ming-zhi 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第11期2831-2840,共10页
The influence of enlarged section parameters on pressure transients of high-speed train passing through a tunnel was investigated by numerical simulation.The calculation results obtained by the structured and unstruct... The influence of enlarged section parameters on pressure transients of high-speed train passing through a tunnel was investigated by numerical simulation.The calculation results obtained by the structured and unstructured grid and the experimental results of smooth wall tunnel were verified.Numerical simulation studies were conducted on three tunnel enlarged section parameters,the enlarged section distribution along circumferential direction,the enlarged section area and the enlarged section distribution along tunnel length direction.The calculation results show that the influence of the different enlarged section distributions along tunnel circumferential direction on pressure transients in the tunnel is basically consistent.There is an optimal enlarged section area for the minimum value of the pressure variation amplitude and the average pressure variation in the tunnel.The law of the pressure variation amplitude and the average pressure variation of the enlarged section distribution along tunnel length direction are obtained. 展开更多
关键词 high-speed train enlarged section parameters TUNNEL pressure transients
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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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Comparative investigations of pressure waves induced by trains passing through a tunnel with different speed modes 被引量:5
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作者 ZHOU Miao-miao LIU Tang-hong +2 位作者 XIAYu-tao LIWen-hui CHEN Zheng-wei 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第8期2639-2653,共15页
Pressure waves induced by high-speed trains passing through a tunnel have adverse effects on train structures and passenger comfort. These adverse effects can be alleviated when the train passing through the tunnel wi... Pressure waves induced by high-speed trains passing through a tunnel have adverse effects on train structures and passenger comfort. These adverse effects can be alleviated when the train passing through the tunnel with a speed mode of deceleration. Thus, to investigate the effect of speed modes on pressure waves, three-dimensional compressible unsteady Reynolds-averaged Navier-Stokes simulations and the sliding mesh are used to simulate pressure waves on train surfaces and tunnel walls when trains passing through a tunnel with three different speed modes(a constant speed at350 km/h, a uniform deceleration from 350 to 300 km/h, and another uniform deceleration from 350 to 250 km/h).Compared with the constant speed, the peak-to-peak of the train surface pressure under the other two speed modes reaches a maximum difference of 11.0%. The maximum positive pressure difference of the tunnel wall under different speed modes is caused by the different attenuation of the friction effect when the train enters the tunnel, and the maximum difference is 12.8%. The difference of the maximum negative pressure on the tunnel wall is caused by the different speed and pressure wave intensity of the train arriving at the same measuring point in different speed modes,and the maximum difference is 15.8%. Hence, it can be concluded that a speed mode of deceleration for trains passing a tunnel can effectively alleviate the aerodynamic effect in the tunnel, especially for the pressure on the tunnel wall. 展开更多
关键词 high-speed trains tunnel aerodynamics pressure wave DECELERATION
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A Numerical Study of the Aerodynamic Characteristics of a High-Speed Train under the Effect of Crosswind and Rain 被引量:9
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作者 Haiqing Li Mengge Yu +1 位作者 Qian Zhang Heng Wen 《Fluid Dynamics & Materials Processing》 EI 2020年第1期77-90,共14页
The performances of high-speed trains in the presence of coupling effects with crosswind and rain have attracted great attention in recent years.The objective of the present paper was to investigate the aerodynamic ch... The performances of high-speed trains in the presence of coupling effects with crosswind and rain have attracted great attention in recent years.The objective of the present paper was to investigate the aerodynamic characteristics of a high-speed train under such conditions in the framework of an Eulerian-Lagrangian approach.An aerodynamic model of a high-speed train was first set up,and the side force coefficient obtained from numerical simulation was compared with that provided by wind tunnel experiments to verify the accuracy of the approach.Then,the effects of the yaw angle,the resultant wind speed,and the rainfall rate on aerodynamic coefficients were analyzed.The results indicate that the aerodynamic coefficients grow almost linearly with the rainfall rate,and increase with a decrease in the resultant wind speed.Due to the impact of raindrops on the train surface and the airflow,the pressure coefficients of windward and leeward side of the train become larger with the increase of the rainfall rate.Raindrops can accelerate the airflow and suppress the vortices detachment.Moreover,the flow velocity in regions surrounding the train increases with an increase in the rainfall rate. 展开更多
关键词 High-speed trains Eulerian-Lagrangian crosswinds and rains aerodynamic coefficients pressure coefficients velocity distribution
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Influence of vapor pressure deficit on vegetation growth in China 被引量:1
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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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Aerodynamic performances and vehicle dynamic response of high-speed trains passing each other 被引量:7
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作者 Yinghui ZHAO Jiye ZHANG +1 位作者 Tian LI Weihua ZHANG 《Journal of Modern Transportation》 2012年第1期36-43,共8页
Based on the aerodynamics and vehicle dynamics, the aerodynamic performances and vehicle dynamic characteristics of two high-speed trains passing each other on the ground, embankment and bridge are studied. Firstly, a... Based on the aerodynamics and vehicle dynamics, the aerodynamic performances and vehicle dynamic characteristics of two high-speed trains passing each other on the ground, embankment and bridge are studied. Firstly, a train aerodynamic model and a vehicle dynamic model are established. Through the simulation of the two models, the pressure waves, aerodynamic forces, and vehicle dynamic responses are obtained. Then, the pressure waves and aero- dynamic forces on different foundations are compared. The results show that the variation trends of pressure wave and aerodynamic forces of trains passing each other on different foundations are almost similar. The peak-to-peak differ- ences in pressure wave and aerodynamic force are below 4% and 3% in three cases in open air. Besides, the differences of security indexes, including coefficient of derailment, wheel unloading rate, the wheelset lateral force, and the wheel- rail vertical force, are below 2% among the three cases; the differences of comfort indexes, including the lateral acceleration and the vertical acceleration, are also below 2%. It is concluded that the dynamic performances of trains pass- ing each other are influenced little by different foundations in open air. 展开更多
关键词 trains passing each other FOUNDATIONS pressure wave AERODYNAMICS vehicle dynamics
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The approach to calculate the aerodynamic drag of maglev train in the evacuated tube 被引量:10
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作者 Jiaqing Ma Dajing Zhou +2 位作者 Lifeng Zhao Yong Zhang Yong Zhao 《Journal of Modern Transportation》 2013年第3期200-208,共9页
In order to study the relationships between the aerodynamic drag of maglev and other factors in the evacuated tube, the formula of aerodynamic drag was deduced based on the basic equations of aerodynamics and then the... In order to study the relationships between the aerodynamic drag of maglev and other factors in the evacuated tube, the formula of aerodynamic drag was deduced based on the basic equations of aerodynamics and then the calculated result was confirmed at a low speed on an experimental system developed by Superconductivity and New Energy R&D Center of South Jiaotong University. With regard to this system a high temperature superconducting magnetic levitation vehicle was motivated by a linear induction motor (LIM) fixed on the permanent magnetic guideway. When the vehicle reached an expected speed, the LIM was stopped. Then the damped speed was recorded and used to calculate the experimental drag. The two results show the approximately same relationship between the aerodynamic drag on the maglev and the other factors such as the pressure in the tube, the velocity of the maglev and the blockage ratio. Thus, the pressure, the velocity, and the blockage ratio are viewed as the three important factors that contribute to the energy loss in the evacuated tube transportation. 展开更多
关键词 Evacuated tube Maglev train Aerodynamic drag pressure in the tube
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Aerodynamic characteristics of a high-speed train crossing the wake of a bridge tower from moving model experiments 被引量:5
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作者 Jinfeng Wu Xiaozhen Li +1 位作者 C.S.Cai Dejun Liu 《Railway Engineering Science》 2022年第2期221-241,共21页
In a strong crosswind,the wake of a bridge tower will lead to an abrupt change of the aerodynamic forces acting on a vehicle passing through it,which may result in problems related to the transportation safety.This st... In a strong crosswind,the wake of a bridge tower will lead to an abrupt change of the aerodynamic forces acting on a vehicle passing through it,which may result in problems related to the transportation safety.This study investigates the transient aerodynamic characteristics of a high-speed train moving in a truss girder bridge and passing by a bridge tower in a wind tunnel.The scaled ratio of the train,bridge,and tower are 1:30.Effects of various parameters such as the incoming wind speed,train speed,and yaw angle on the aerodynamic performance of the train were considered.Then the sudden change mechanism of aerodynamic loads on the train when it crosses over the tower was further discussed.The results show that the bridge tower has an apparent shielding effect on the train passing through it,with the influencing width being larger than the width of the tower.The train speed is the main factor affecting the influencing width of aerodynamic coefficients,and the mutation amplitude is mainly related to the yaw angle obtained by changing the incoming wind speed or train speed.The vehicle movement introduces an asymmetry of loading on the train in the process of approaching and leaving the wake of the bridge tower,which should not be neglected. 展开更多
关键词 Vehicle aerodynamics Wind tunnel test Moving train Bridge tower Shielding effect Sudden change mechanism Truss bridge
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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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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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Effects of sudden change in wind loads on running performance of trains on a highway-railway one-story bridge in crosswinds 被引量:1
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作者 HAN Yan LIU Ye +2 位作者 CAI Chun-sheng HU Peng HE Xu-hui 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第8期2621-2638,共18页
To investigate the effects of sudden change in wind loads on the running performance of trains on the bridge in crosswinds,a highway-railway one-story bridge was taken as the research object.Aerodynamic coefficients o... To investigate the effects of sudden change in wind loads on the running performance of trains on the bridge in crosswinds,a highway-railway one-story bridge was taken as the research object.Aerodynamic coefficients of the train and the bridge were measured in a series of train-bridge system segment models through wind tunnel tests when two trains passed each other on the bridge and when a train entered and left the wind barrier section of the bridge.Based on the improved SIMPACK and ANSYS rigid-flexible coupling simulation method,a wind-double train-track-bridge system coupled vibration model was established.The dynamic responses of the train were analyzed under the effects of sudden change in wind loads caused by two trains passing each other and a train entering and leaving the wind barrier section of the bridge.The results show that the effects of sudden wind load change caused by the trains passing each other had less effects on the running safety of the leeward-side train than the wind shielding effect caused by the windward-side train in the wind speed range of 10−25 m/s.With the decrease in the porosity of wind barriers,the effects of the sudden wind load change played an increasingly important role in the running safety and comfort of the train.With the increase in wind speed,the lateral response of the train increased obviously because of the effects of sudden wind load change,which affects both the lateral running stability and the comfort of the train. 展开更多
关键词 wind-train-track-bridge system two trains passing each other wind barrier sudden change in wind load dynamic response
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