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Near-zone Direct and Indirect Topographic Effects Based on the Rectangular Prism and Surface Element
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作者 Jian MA Ziqing WEI +2 位作者 Zhenghui YANG Xiaogang LIU Jianfeng JI 《Journal of Geodesy and Geoinformation Science》 2019年第3期8-17,共10页
Helmert’s second method of condensation is an effective method for terrain reduction in the geoid and quasi-geoid determinations. Condensing the masses outside the geoid to a surface layer on the geoid produces sever... Helmert’s second method of condensation is an effective method for terrain reduction in the geoid and quasi-geoid determinations. Condensing the masses outside the geoid to a surface layer on the geoid produces several forms of topographic effects: direct effect on gravity, secondary indirect effect on gravity and indirect effects on the (quasi-) geoid, respectively. To strike a balance between computation accuracy and numerical efficiency, the global integration region of topographic effects is usually divided into near zone and far zone. We focus on the computation of near-zone topographic effects, which are functions of actual topographic masses and condensed masses. Since there have already been mature formulas for gravitational attraction and potential of actual topographic masses using rectangular prism model, we put forward surface element model for condensed masses. Afterwards, the formulas for near-zone direct and indirect effects are obtained easily by combining the rectangular prism model and surface element model. To overcome the planar approximation errors involved with the new formulas for near-zone topographic effects, the Earth’s curvature can be taken into account. It is recommended to apply the formulas based on the rectangular prism and surface element considering the Earth’s curvature to calculate near-zone topographic effects for high-accuracy demand to determine geoid and quasi-geoid. 展开更多
关键词 helmert's second method of condensation DIRECT effect indirect effect rectangular PRISM SURFACE ELEMENT
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Indirect Radiative Forcing and Climatic Effect of the Anthropogenic Nitrate Aerosol on Regional Climate of China 被引量:14
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作者 李树 王体健 +1 位作者 庄炳亮 韩永 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2009年第3期543-552,共10页
The regional climate model (RegCM3) and a tropospheric atmosphere chemistry model (TACM) were coupled, thus a regional climate chemistry modeling system (RegCCMS) was constructed, which was applied to investigat... The regional climate model (RegCM3) and a tropospheric atmosphere chemistry model (TACM) were coupled, thus a regional climate chemistry modeling system (RegCCMS) was constructed, which was applied to investigate the spatial distribution of anthropogenic nitrate aerosols, indirect radiative forcing, as well as its climatic effect over China. TACM includes the thermodynamic equilibrium model ISORROPIA and a condensed gas-phase chemistry model. Investigations show that the concentration of nitrate aerosols is relatively high over North and East China with a maximum of 29μg m-3 in January and 8 μg m-3 in July. Due to the influence of air temperature on thermodynamic equilibrium, wet scavenging of precipitation and the monsoon climate, there are obvious seasonal differences in nitrate concentrations. The average indirect radiative forcing at the tropopause due to nitrate aerosols is -1.63 W m 2 in January and -2.65 W m 2 in July, respectively. In some areas, indirect radiative forcing reaches -10 W m-2. Sensitivity tests show that nitrate aerosols make the surface air temperature drop and the precipitation reduce on the national level. The mean changes in surface air temperature and precipitation are 0.13 K and -0.01 mm d-1 in January and -0.09 K and -0.11 mm d-1 in July, respectively, showing significant differences in different regions. 展开更多
关键词 nitrate aerosol indirect radiative forcing indirect climate effect regional climate atmosphericchemistry
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Modeling Study of Aerosol Indirect Effectson Global Climate with an AGCM 被引量:4
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作者 王志立 张华 +2 位作者 沈学顺 龚山陵 张小曳 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2010年第5期1064-1077,共14页
Aerosol indirect effects (AIEs) on global climate were quantitatively investigated by introducing aerosol–cloud interaction parameterizations for water stratus clouds into an AGCM (BCC AGCM2.0.1), which was devel... Aerosol indirect effects (AIEs) on global climate were quantitatively investigated by introducing aerosol–cloud interaction parameterizations for water stratus clouds into an AGCM (BCC AGCM2.0.1), which was developed by the National Climate Center of the China Meteorological Administration. The study yielded a global annual mean of -1.14 W m^-2 for the first indirect radiative forcing (IRF), with an obvious seasonal change. In summer, large forcing mainly occurred in mid to high latitudes of the Northern Hemisphere, whereas in winter, large values were found at 60°S. The second indirect effect led to global annual mean changes in net shortwave flux of -1.03 W m^-2 at the top of the atmosphere (TOA), which was relatively significant in mid-latitude regions of both hemispheres. The total AIE reduced the global annual means of net shortwave flux at the TOA and of surface temperature by 1.93 W m^-2 and 0.12 K, respectively. Change in surface temperature induced by the total AIE was clearly larger in the Northern Hemisphere (-0.23 K) than in the Southern Hemisphere, where changes were negligible. The interhemispheric asymmetry in surface cooling resulted in significant differences in changes of the interhemispheric annual mean precipitation rate, which could lead to a tendency for the ITCZ to broaden. The total AIE decreased the global annual mean precipitation rate by 0.055 mm df^-1. 展开更多
关键词 AEROSOL CLOUD RADIATION indirect effect
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Analytical Studies of the Cloud Droplet Spectral Dispersion Influence on the First Indirect Aerosol Effect 被引量:5
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作者 解小宁 刘晓东 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2013年第5期1313-1319,共7页
Atmospheric aerosols (acting as cloud condensation nuclei) can enhance the cloud droplet number concentration and reduce the cloud droplet size, and in turn affect the cloud optical depth, as well as the cloud albed... Atmospheric aerosols (acting as cloud condensation nuclei) can enhance the cloud droplet number concentration and reduce the cloud droplet size, and in turn affect the cloud optical depth, as well as the cloud albedo, and thereby exert a radiative influence on climate (the first indirect aerosol effect). In this paper, based on various relationships between cloud droplet spectral dispersion (c) and cloud droplet number concentration (Nc), we analytically derive the corresponding expressions of the cloud radiative forcing induced by changes in the cloud droplet number concentration. Further quantitative evaluation indicates that the cloud radiative forcing induced by aerosols for the different ^-Nc relationships varies from -29.1% to 25.2%, compared to the case without considering spectral dispersion (e = 0). Our results suggest that an accurate description of e - Nc relationships helps to reduce the uncertainty of the first indirect aerosol effect and advances our scientific understanding of aerosol-cloud-radiation interactions. 展开更多
关键词 spectral dispersion cloud radiative forcing the first indirect aerosol effect
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First Surface-based Estimation of the Aerosol Indirect Effect over a Site in Southeastern China 被引量:2
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作者 Jianjun LIU Zhanqing LI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2018年第2期169-181,共13页
The deployment of the U.S. Atmospheric Radiation Measurement mobile facility in Shouxian from May to December 2008 amassed the most comprehensive set of measurements of atmospheric, surface, aerosol, and cloud variabl... The deployment of the U.S. Atmospheric Radiation Measurement mobile facility in Shouxian from May to December 2008 amassed the most comprehensive set of measurements of atmospheric, surface, aerosol, and cloud variables in China. This deployment provided a unique opportunity to investigate the aerosol-cloud interactions, which are most challenging and, to date, have not been examined to any great degree in China. The relationship between cloud droplet effective radius (CER) and aerosol index (AI) is very weak in summer because the cloud droplet growth is least affected by the competition for water vapor. Mean cloud liquid water path (LWP) and cloud optical depth (COD) significantly increase with increasing AI in fall. The sensitivities of CER and LWP to aerosol loading increases are not significantly different under different air mass conditions. There is a significant correlation between the changes in hourly mean AI and the changes in hourly mean CER, LWP, and COD. The aerosol first indirect effect (FIE) is estimated in terms of relative changes in both CER (FIEcER) and COD (FIEcoD) with changes in AI for different seasons and air masses. FIEcoD and FIEcER are similar in magnitude and close to the typical FIE value of - 0.23, and do not change much between summer and fall or between the two different air mass conditions. Similar analyses were done using spaceborne Moderate Resolution Imaging Spectroradiometer data. The satellite-derived FIE is contrary to the FIE estimated from surface retrievals and may have large uncertainties due to some inherent limitations. 展开更多
关键词 ground-based measurements aerosol indirect effect southeastern China
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Indirect Radiative and Climatic Effects of Sulfate and Organic Carbon Aerosols over East Asia Investigated by RIEMS 被引量:3
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作者 WU Peng-Ping HAN Zhi-Wei 《Atmospheric and Oceanic Science Letters》 2011年第1期7-11,共5页
The indirect radiative and climatic effects of sulfate and organic carbon aerosols over East Asia were investigated using a Regional Integrated Environment Model System (RIEMS) with an empirical aerosol-cloud paramete... The indirect radiative and climatic effects of sulfate and organic carbon aerosols over East Asia were investigated using a Regional Integrated Environment Model System (RIEMS) with an empirical aerosol-cloud parameterization.The first indirect radiative forcing was negative and ranged from-9-0 W m-2 in the domain.The maximum cooling,up to-9 W m-2,occurred in the Chongqing District in winter,whereas the cooling areas were larger during summer than in winter.Organic carbon (OC) aerosols were more abundant in winter than in summer,whereas the sulfate concentration during summer was much higher than during winter.The concentrations of sulfate and OC were comparable in winter,and sulfate played a dominant role in determining indirect radiative forcing in summer,whereas in winter,both sulfate and OC were important.The regional mean indirect radiative forcings were-0.73 W m-2 and-0.41 W m-2 in summer and winter,respectively.The surface cooling caused by indirect effects was more obvious in winter than that in summer.The ground temperature decreased by ~1.2 K in most areas of eastern China in winter,whereas in summer,the temperature decreased (~-1.5 K) in some regions,such as the Yangtze River region,but increased (~0.9 K) in the areas between the Yellow and Yangtze Rivers.In winter,the precipitation decreased by 0-6 mm in most areas of eastern China,but in summer,alternating bands of increasing (up to 80 mm) and decreasing (~-80 mm) precipitation appeared in eastern China. 展开更多
关键词 indirect radiative forcing climatic effect SULFATE organic carbon RIEMS
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An improved recommendation algorithm via weakening indirect linkage effect 被引量:1
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作者 陈光 邱天 沈小泉 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第7期606-611,共6页
We propose an indirect-link-weakened mass diffusion method(IMD), by considering the indirect linkage and the source object heterogeneity effect in the mass diffusion(MD) recommendation method. Experimental results... We propose an indirect-link-weakened mass diffusion method(IMD), by considering the indirect linkage and the source object heterogeneity effect in the mass diffusion(MD) recommendation method. Experimental results on the MovieLens, Netflix, and RYM datasets show that, the IMD method greatly improves both the recommendation accuracy and diversity, compared with a heterogeneity-weakened MD method(HMD), which only considers the source object heterogeneity. Moreover, the recommendation accuracy of the cold objects is also better elevated in the IMD than the HMD method. It suggests that eliminating the redundancy induced by the indirect linkages could have a prominent effect on the recommendation efficiency in the MD method. 展开更多
关键词 bipartite network mass diffusion recommender system indirect linkage effect
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Modeling of the Second Indirect Effect of Anthropogenic Aerosols in East Asia 被引量:2
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作者 WU Peng-Ping HAN Zhi-Wei 《Atmospheric and Oceanic Science Letters》 2011年第6期316-323,共8页
This study investigated the second indirect climatic effect of anthropogenic aerosols,including sulfate,organic carbon(OC) ,and black carbon(BC) ,over East Asia.The seasonal variation of the climatic response to the s... This study investigated the second indirect climatic effect of anthropogenic aerosols,including sulfate,organic carbon(OC) ,and black carbon(BC) ,over East Asia.The seasonal variation of the climatic response to the second indirect effect was also characterized.The simulation period for this study was 2006.Due to a decrease in autoconversion rate from cloud water to rain as a result of aerosols,the cloud liquid water path(LWP) ,and radiative flux(RF) at the top of the atmosphere(TOA) changed dramatically,increasing by 14.3 g m-2 and decreasing by-4.1 W m-2 in terms of domain and annual average.Both LWP and RF changed most in autumn. There were strong decreases in ground temperature in Southwest China,the middle reaches of the Yangtze River in spring and autumn,while maximum cooling of up to-1.5 K occurred in the Chongqing district.The regional and annual mean change in ground temperature reached-0.2 K over eastern China.In all seasons except summer,precipitation generally decreased in most areas north of the Yangtze River,whereas precipitation changed little in South China.Precipitation changed most in summer,with alternating bands of increasing(~40 mm) and decreasing(~40 mm) precipitation appearing in eastern China.Precipitation decreased by 1.5-40 mm over large areas of Northeast China and the Huabei Plain.The domain and annual mean change in precipitation was approximately-0.3 mm over eastern China.The maximum reduction in precipitation occurred in summer,with mean absolute and relative changes of-1.2 mm and-3.8%over eastern China.This study revealed considerable climate responses to the second indirect effect of aerosols over specific regions of China. 展开更多
关键词 AEROSOLS second indirect effect autoconversion liquid water path model simulation
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Aerosol Indirect Effects on Warm Clouds in the Grid-Point Atmospheric Model of IAP LASG(GAMIL) 被引量:7
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作者 Shi Xiang-Jun Wang Bin +3 位作者 Liu Xiao-Hong Wang Ming-Huai Li Li-Juan Dong Li 《Atmospheric and Oceanic Science Letters》 2010年第4期237-241,共5页
Aerosol indirect effects on warm clouds are estimated in the Grid-point Atmospheric Model of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmosphe... Aerosol indirect effects on warm clouds are estimated in the Grid-point Atmospheric Model of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics(IAP LASG)(GAMIL) with a new two-moment cloud microphysics scheme using two different physically-based aerosol activation parameterizations:Abdul-Razzak and Ghan,and Nenes and Seinfeld.The annual global mean changes in shortwave cloud forcing from preindustrial times to present day(a measure of the aerosol indirect effects) estimated from these two parameterizations are remarkably similar:0.76 W m?2 with the Abdul-Razzak and Ghan parameterization,and 0.78 W m?2 with the Nenes and Seinfeld parameterization.Physically-based parameterizations can provide robust representations of aerosol effects on droplet nucleation,meaning that aerosol activation is no longer the most uncertain factor in modeling aerosol indirect effects. 展开更多
关键词 aerosol indirect effect droplet nucleation atmospheric model GAMIL
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Observation on the Therapeutical Effect of Adjuvant Arthritis in Rats with Medicinal Indirect Moxibustion
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作者 Zhu Baijun Wang Yuanchao +1 位作者 Dai Huiting Xu Qingyan(Institute of Acupuncture and Moxibustion China Academy of TCM, 100700) 《中国针灸》 CAS CSCD 北大核心 1995年第S2期240-241,共2页
ObservationontheTherapeuticalEffectofAdjuvantArthritisinRatswithMedicinalIndirectMoxibustion¥ZhuBaijun;WangY... ObservationontheTherapeuticalEffectofAdjuvantArthritisinRatswithMedicinalIndirectMoxibustion¥ZhuBaijun;WangYuanchao;DaiHuitin... 展开更多
关键词 OBSERVATION ARTHRITIS effect indirect MEDICINAL MOXIBUSTION ADJUVANT RATS Therapeutical in
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On the parameters for electrocaloric effect predicted by indirect method
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作者 刘宏波 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第11期486-488,共3页
The influences of specific heat capacity CP, temperature step ?T, electric field step ?E, and initial electric field E1 on predicted electrocaloric(EC) temperature ?T of monodomain Ba TiO3 are examined by combini... The influences of specific heat capacity CP, temperature step ?T, electric field step ?E, and initial electric field E1 on predicted electrocaloric(EC) temperature ?T of monodomain Ba TiO3 are examined by combining the Maxwell equation and phenomenological theory. Since the procedure is similar to indirect measurement of the EC effect, the results can serve as a reference for experiments. The results suggest that(i) it is reasonable to use zero-field CP,(ii) optimized ?T should be 2 K,(iii) it is better to keep △E 〈 EC, and(iv) E1〈 EC. Here, EC is the coercive field of material. 展开更多
关键词 electrocaloric effect indirect method BaTiO3
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Behavior of exciton in direct−indirect band gap Al_(x)Ga_(1−x)As crystal lattice quantum wells
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作者 Yong Sun Wei Zhang +10 位作者 Shuang Han Ran An Xin-Sheng Tang Xin-Lei Yu Xiu-Juan Miao Xin-Jun Ma Xianglian Pei-Fang Li Cui-Lan Zhao Zhao-Hua Ding Jing-Lin Xiao 《Journal of Semiconductors》 EI CAS CSCD 2024年第3期64-70,共7页
Excitons have significant impacts on the properties of semiconductors.They exhibit significantly different properties when a direct semiconductor turns in to an indirect one by doping.Huybrecht variational method is a... Excitons have significant impacts on the properties of semiconductors.They exhibit significantly different properties when a direct semiconductor turns in to an indirect one by doping.Huybrecht variational method is also found to influence the study of exciton ground state energy and ground state binding energy in Al_(x)Ga_(1−x)As semiconductor spherical quantum dots.The Al_(x)Ga_(1−x)As is considered to be a direct semiconductor at AI concentration below 0.45,and an indirect one at the concentration above 0.45.With regards to the former,the ground state binding energy increases and decreases with AI concentration and eigenfrequency,respectively;however,while the ground state energy increases with AI concentration,it is marginally influenced by eigenfrequency.On the other hand,considering the latter,while the ground state binding energy increases with AI concentration,it decreases with eigenfrequency;nevertheless,the ground state energy increases both with AI concentration and eigenfrequency.Hence,for the better practical performance of the semiconductors,the properties of the excitons are suggested to vary by adjusting AI concentration and eigenfrequency. 展开更多
关键词 exciton effects aluminum gallium arsenide crystal direct band gap semiconductor indirect band gap semiconductor
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Infrared laser-induced fast photovoltaic effect observed in orthorhombic tin oxide film
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作者 赵嵩卿 张际蕊 +5 位作者 施宏杰 闫坤坤 黄春 杨立敏 杨睿 赵昆 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第2期406-409,共4页
The SnO_2/SnO with an orthorhombic structure is a material known to be stable at high pressures and temperatures and expected to have new optical and electrical properties. The authors report a new finding of the infr... The SnO_2/SnO with an orthorhombic structure is a material known to be stable at high pressures and temperatures and expected to have new optical and electrical properties. The authors report a new finding of the infrared laser induced a fast photovoltaic effect arising from orthorhombic tin oxide film with an indirect band gap(~2.4 e V) which is deposited by pulsed laser deposition. The rising time of the photovoltaic signal is about 3 ns with a peak value of 4.48 mV under the pulsed laser beam with energy density 0.015 m J/mm^2. The relation between the photovoltages and laser positions along the line between two electrodes of the film is also exhibited. A possible mechanism is put forward to explain this phenomenon.All data and analyses demonstrate that the orthorhombic tin oxide with an indirect band gap could be used as a candidate for an infrared photodetector which can be operated at high pressures and temperatures. 展开更多
关键词 polycrystalline tin oxide film ORTHORHOMBIC infrared laser induced lateral photovoltaic effect (LPV) indirect band gap
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A Simple Method of Measuring Vaccine Effects on Infectiousness and Contagion
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作者 Yasutaka Chiba 《Open Journal of Statistics》 2013年第4期7-15,共9页
The vaccination of one person may prevent another from becoming infected, either because the vaccine may prevent the first person from acquiring the infection and thereby reduce the probability of transmission to the ... The vaccination of one person may prevent another from becoming infected, either because the vaccine may prevent the first person from acquiring the infection and thereby reduce the probability of transmission to the second, or because, if the first person is infected, the vaccine may impair the ability of the infectious agent to initiate new infections. The former mechanism is referred as a contagion effect and the latter is referred as an infectiousness effect. By applying a principal stratification approach, the conditional infectiousness effect has been defined, but the contagion effect is not defined using this approach. Recently, new definitions of unconditional infectiousness and contagion effects were provided by applying a mediation analysis approach. In addition, a simple relationship between conditional and unconditional infectiousness effects was found under a number of assumptions. These two infectiousness effects can be assessed by very simple estimation and sensitivity analysis methods under the assumptions. Nevertheless, such simple methods to assess the contagion effect have not been discussed. In this paper, we review the methods of assessing infectiousness effects, and apply them to the inference of the contagion effect. The methods provided here are illustrated with hypothetical vaccine trial data. 展开更多
关键词 indirect effect INTERFERENCE MEDIATION Analysis Potential OUTCOME Principal STRATIFICATION
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Model Analysis of the Anthropogenic Aerosol Effect on Clouds over East Asia
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作者 GAO Yi ZHANG Mei-Gen +1 位作者 LIU Xiao-Hong ZHAO Chun 《Atmospheric and Oceanic Science Letters》 2012年第1期1-7,共7页
A coupled meteorology and aerosol/chemistry model WRF-Chem (Weather Research and Forecast model coupled with Chemistry) was used to conduct a pair of simulations with present-day (PD) and preindustrial (P1) emis... A coupled meteorology and aerosol/chemistry model WRF-Chem (Weather Research and Forecast model coupled with Chemistry) was used to conduct a pair of simulations with present-day (PD) and preindustrial (P1) emissions over East Asia to examine the aerosol indirect effect on clouds. As a result of an increase in aerosols in January, the cloud droplet number increased by 650 cm-3 over the ocean and East China, 400 cm-3 over Central and Southwest China, and less than 200 cm-3 over North China. The cloud liquid water path (LWP) increased by 40-60 g m-2 over the ocean and Southeast China and 30 g m-2 over Central China; the LWP in- creased less than 5 g m-2 or decreased by 5 g m2 over North China. The effective radius (Re) decreased by more than 4 pm over Southwest, Central, and Southeast China and 2 pm over North China. In July, variations in cloud properties were more uniform; the cloud droplet number increased by approximately 250400 cm-3, the LWP increased by approximately 30-50 g m 2, and Re decreased by approximately 3 μm over most regions of China. In response to cloud property changes from PI to PD, shortwave (SW) cloud radiative m-2 over the ocean and 10 forcing strengthened by 30 W W m-2 over Southeast China, and it weakened slightly by approximately 2-10 W m-2 over Central and Southwest China in January. In July, SW cloud radiative forcing strengthened by 15 W m-2 over Southeast and North China and weakened by l0 W m-2 over Central China. The different responses of SW cloud radiative forcing in different regions was related to cloud feedbacks and natural variability. 展开更多
关键词 WRF-Chem aerosol indirect effect cloud properties cloud radiative forcing
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Numerical study of aerosol effect on three types of clouds and precipitation in Beijing area
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作者 ZhiGuo Yue XiaoDong Liu ShuYan Liu 《Research in Cold and Arid Regions》 2012年第4期342-350,共9页
Three types of rainfall (storm, moderate and slight rainfall) in the Beijing area were simulated by the Weather Research and Fore- cast (WRF3.2) model coupled with Milbrandt-two-moment cloud microphysics scheme, t... Three types of rainfall (storm, moderate and slight rainfall) in the Beijing area were simulated by the Weather Research and Fore- cast (WRF3.2) model coupled with Milbrandt-two-moment cloud microphysics scheme, to explore the effect of aerosols on clouds and precipitation under continental and maritime aerosol scenarios. Results indicate that an increase of aerosols has various effects on clouds and precipitation. (1) The amount of surface precipitation is obviously affected. With an increase of aerosol con- centration, the 48-hr total precipitation of storm and moderate rainfall decreased by 23% and 16.6%, respectively, and the 24-hr total precipitation of slight rainfall decreased by 14.0%. (2) The distribution of surface precipitation is also clearly affected. The average precipitation for a rain storm increases in most parts of western Beijing and decreases by more than 20 mm in most parts of eastern Beijing with increasing aerosol concentration. The average precipitation of moderate rainfall decreases by 0.1-5 mm in most parts of the Beijing area. The effect of increased aerosol concentration is weak for slight rainfall distribution in the study area. (3) With an increase of aerosol concentration, a narrower width and lower precipitation peak value are found in the storm rainfall, and its duration is prolonged for the high aerosol concentration. An earlier precipitation termination of moderate rainfall is found with increasing aerosol concentration. (4) The upper-air hydrometeors vary with aerosol concentration, For storm and moderate rainfall, significantly higher cloud water concentration and lower rain water were found under the continental aerosol scenario. 展开更多
关键词 AEROSOL Beijing area clouds and precipitation indirect effect numerical simulation
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碳排放权交易对试点地区绿色发展的影响及溢出效应——基于PSM-DID和SDID模型的实证分析 被引量:1
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作者 余谦 吴婷 +1 位作者 覃一冬 贾鹏 《工业技术经济》 CSSCI 北大核心 2024年第3期104-114,共11页
在碳中和、碳达峰背景下,本文选用2003~2021年全国273个地级市的面板数据,以碳排放权交易试点(CETP)为出发点,用生态效率测度绿色发展水平,通过PSM-DID和SDID模型实证检验了CETP对绿色发展的直接效应、间接效应和空间溢出效应。研究发现... 在碳中和、碳达峰背景下,本文选用2003~2021年全国273个地级市的面板数据,以碳排放权交易试点(CETP)为出发点,用生态效率测度绿色发展水平,通过PSM-DID和SDID模型实证检验了CETP对绿色发展的直接效应、间接效应和空间溢出效应。研究发现:(1)CETP能显著促进绿色发展,且通过了安慰剂检验和稳健性检验;(2)CETP产生的创新效应对绿色发展有推动作用,但产业结构效应不显著;(3)CETP对周边试点城市产生了显著负向的溢出效应,但对非试点城市的生态效率无明显影响。最后,结合以上研究结论,提出了政策建议。 展开更多
关键词 碳排放权交易试点 绿色发展水平 生态效率 间接效应 空间溢出效应 碳配额
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Effect of ligamentum teres uteri preservation in laparoscopic high hernia sac ligation in children with indirect inguinal hernia
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作者 Xiao-Qiang Lin Hua-Fang Li +1 位作者 Yan-Zhu Lin Wen-You Chen 《World Journal of Gastrointestinal Surgery》 2025年第1期132-138,共7页
BACKGROUND Routinely separating the ligamentum teres uteri(LTU)intraoperatively remains an unresolved issue for female children undergoing surgery for indirect inguinal hernia(IIH).AIM To identify the effect of LTU pr... BACKGROUND Routinely separating the ligamentum teres uteri(LTU)intraoperatively remains an unresolved issue for female children undergoing surgery for indirect inguinal hernia(IIH).AIM To identify the effect of LTU preservation in laparoscopic high hernia sac ligation(LHSL)in children with IIH.METHODS The participants were 100 female children with unilateral IIH admitted from April 2022 to January 2024 to the Pediatric Surgery Department of Zhangzhou Municipal Hospital of Fujian Province.They were categorized based on LTU retention into the control group(n=45 cases),which underwent LTU ligation intraoperatively,and the experimental group(55 cases),which had the LTU preserved intraoperatively.All children underwent LHSL.RESULTS This study comparatively analyzed the operation time,hospitalization time,blood loss,postoperative recurrence rate,and complications(repeated pain in the inguinal region,foreign body sensation in the inguinal region,bloody exudation at the inguinal incision,and incision infection),which were all comparable between the two groups.CONCLUSION The above results indicate that LTU preservation during LHSL exerts certain therapeutic benefits for children with IIH.LTU preservation does not increase hospitalization time,blood loss,postoperative recurrence rate,and complications,which is safe and feasible,compared with conventional LTU ligation.LHSL with LTU preservation should be performed if conditions permit,which is worth popularizing. 展开更多
关键词 indirect inguinal hernia Laparoscopic high hernia sac ligation Ligamentum teres uteri Therapeutic effect Pediatric surgery
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雷电间接效应多重脉冲组电流产生装置的设计
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作者 刘宏伟 栾崇彪 +3 位作者 袁建强 肖金水 黄宇鹏 王凌云 《强激光与粒子束》 CAS CSCD 北大核心 2024年第2期1-7,共7页
针对雷电间接效应多重脉冲组电流模拟需求,完成了雷电间接效应多重脉冲组模拟源的设计,采用20个Crowbar电路支路,通过分时放电的方式实现1个脉冲串内多脉冲输出需求,每个支路可以实现最小间隔30 ms的重复频率放电,从而实现3个脉冲串的... 针对雷电间接效应多重脉冲组电流模拟需求,完成了雷电间接效应多重脉冲组模拟源的设计,采用20个Crowbar电路支路,通过分时放电的方式实现1个脉冲串内多脉冲输出需求,每个支路可以实现最小间隔30 ms的重复频率放电,从而实现3个脉冲串的输出需求。对放电支路的参数进行了详细设计,分析了电容、波尾电路电感、波尾电路电阻参数变化对输出特性的影响。分析了采用并联大电容实现放电电容重复频率快速充电的可行性,完成了装置的初步结构设计并结合装置结构简要分析了电路模拟参数设置的合理性。该装置建成后,可为电子、电气设备等开展测试提供技术支持。 展开更多
关键词 雷电间接效应 多重脉冲组(H波) 雷电模拟源 冲击电流发生器
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基于非生物指标的鱼道效果评价模型
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作者 郭辉 娄起浩 +3 位作者 陈端 杨文俊 付国栋 金光球 《长江科学院院报》 CSCD 北大核心 2024年第12期82-90,100,共10页
目前鱼道效果评价多采用网捕、PIT跟踪等手段直接评价过鱼数量和效率,存在工作量大、周期长、诊断识别非生物工程问题困难等不足。基于我国鱼道效果已有监测数据,构建鱼道效果评价指标体系,涵盖水力条件适宜度、环境因子适应性、内部结... 目前鱼道效果评价多采用网捕、PIT跟踪等手段直接评价过鱼数量和效率,存在工作量大、周期长、诊断识别非生物工程问题困难等不足。基于我国鱼道效果已有监测数据,构建鱼道效果评价指标体系,涵盖水力条件适宜度、环境因子适应性、内部结构符合度等非生物指标和过鱼有效性等生物指标。典型相关分析表明,进口流速指数、孔缝宽度指数和池室消能指数等水力与结构指标对鱼道效果影响较大,指标权重分别为0.23、0.16和0.15;耦合模糊评价理论,构建了基于非生物指标的鱼道效果评价模型。案例分析表明,模型评价结果与直接监测结论相符,模型可靠性较好,可为我国鱼道运行管理提供技术支撑。 展开更多
关键词 鱼道效果 非生物指标 间接评价模型 典型相关分析 指标适宜度
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