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The Effect of Foreign Direct Investment on Air Pollution in the Economic Community of West African States region: What Influence Does Tax Expenditure Have?
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作者 Symphorien Zogbassè Ahouidji Tanguy Agbokpanzo +2 位作者 Kuessi Prince Houssou Tiburce André Agbidinoukoun Alastaire Sèna Alinsato 《Journal of Environmental Protection》 2023年第11期903-918,共16页
Air pollution is one of the crucial environmental challenges facing the countries of the Economic Community of West African States (ECOWAS). The objective of this paper is to examine the effect of an attractive tax po... Air pollution is one of the crucial environmental challenges facing the countries of the Economic Community of West African States (ECOWAS). The objective of this paper is to examine the effect of an attractive tax policy on the relationship between Foreign Direct Investment (FDI) and air pollution in ECOWAS region over the period 2000 to 2019. By using the Ordinary Least Squares (OLS) method and panel data analyses (fixed effects and random effects), the results show that, in general, FDI does not have a significant effect on air pollution in the region. However, closer analysis reveals that an interaction between FDI and an attractive tax policy has a negative effect on air quality, leading to an increase in air pollution. Thus, companies attracted by tax incentives may not meet rigorous environmental standards. These results highlight the importance for policymakers to balance economic incentives with environmental protection in ECOWAS. Attractive tax policies can stimulate investment, but they must be designed in a way that encourages environmentally friendly practices, thereby helping to improve air quality in the region. 展开更多
关键词 Air Pollution Foreign direct Investment Attractive Tax Policy Ordinary Least Squares Rendom effects
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Existence and Stability of Static Solutions of the Landau-Lifshitz Equation with Multi-direct Effective Field 被引量:5
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作者 Bo Ling GUO Gan Shan YANG 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2004年第6期1135-1152,共18页
We prove the existence of solutions of the static Landau-Lifshitz equation with multi- direct effective field and with Dirichlet boundary condition,and establish the stability of the solution of Landau-Lifshitz equati... We prove the existence of solutions of the static Landau-Lifshitz equation with multi- direct effective field and with Dirichlet boundary condition,and establish the stability of the solution of Landau-Lifshitz equation with respect to time. 展开更多
关键词 Landau-Lifshitz equation Liapunov stable Multi-direct effective field
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How aerosol direct effects influence the source contributions to PM2.5 concentrations over Southern Hebei, China in severe winter haze episodes 被引量:2
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作者 Litao Wang Joshua S. Fu +4 位作者 Wei Wei Zhe Wei Chenchen Meng Simeng Ma Jiandong Wang 《Frontiers of Environmental Science & Engineering》 SCIE EI CAS CSCD 2018年第3期145-157,共13页
Beijing-Tianjin-Hebei area is the most air polluted region in China and the three neighborhood southern Hebei cities, Shijiazhuang, Xingtai, and Handan, are listed in the top ten polluted cities with severe PM2.5 poll... Beijing-Tianjin-Hebei area is the most air polluted region in China and the three neighborhood southern Hebei cities, Shijiazhuang, Xingtai, and Handan, are listed in the top ten polluted cities with severe PM2.5 pollution. The objective of this paper is to evaluate the impacts of aerosol direct effects on air aualitv over the southern Hebei cities, as well as the im0acts when considering those effects on source apportionment using three dimensional air quality models. The WRF/Chem model was applied over the East Asia and northern China at 36 and 12 km horizontal grid resolutions, respectively, for the period of January 2013, with two sets of simulations with or without aerosol-meteorology feedbacks. The source contributions of power plants, industrial, domestic, transportation, and agriculture are evaluated using the Brute-Force Method (BFM) under the two simulation configurations. Our results indicate that, although the increases in PM2.5 concentrations due to those effects over the three southern Hebei cities are only 3%-9% on monthly average they are much more significant under high PM2.5 Ioadmgs (-50 gg.m - when PM25 concentrations are higher than 400μg.m^-3). When considering the aerosol feedbacks, the contributions of industrial and domestic sources assessed using the BFM will obviously increase (e.g., from 30% 34% to 32%-37% for industrial), especiallY3under high PM2.5 loadings (e.g., from 36%-44% to 43%-47% for domestic when PM2.5〉400μg·m^-3). Our results imply that the aerosol direct effects should not be ignored during severe pollution episodes, especially in short-term source apportionment using the BFM. 展开更多
关键词 Aerosol direct effect PM2.5 Southern Hebei WRF/Chem Haze
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The Defects and Future Research Direction of the Auditof the Policy Implementation Effect 2 China 被引量:3
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作者 刘利 《石家庄经济学院学报》 2016年第3期97-99,共3页
近年来,政策执行效果审计在中国逐渐引起了关注.论文首先介绍了政策执行效果审计的内涵和研究的意义,在此基础上简要阐述了政策执行效果审计的发展现状,并指出了其缺陷,最后提出了未来的研究应重点关注建立政策执行效果审计理论框架体... 近年来,政策执行效果审计在中国逐渐引起了关注.论文首先介绍了政策执行效果审计的内涵和研究的意义,在此基础上简要阐述了政策执行效果审计的发展现状,并指出了其缺陷,最后提出了未来的研究应重点关注建立政策执行效果审计理论框架体系、完善政策执行效果审计评价指标体系、探索对政策本身的评价以及将政策执行效果审计与新兴互联网工程及信息技术结合起来等几个方面. 展开更多
关键词 政策执行效果审计 缺陷 研究方向
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Direct Climatic Effect of Dust Aerosol in the NCAR Community Atmosphere Model Version 3 (CAM3) 被引量:3
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作者 乐旭 王会军 +1 位作者 廖宏 范可 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2010年第2期230-242,共13页
Direct climate responses to dust shortwave and longwave radiative forcing (RF) are studied using the NCAR Community Atmosphere Model Version 3 (CAM3). The simulated RF at the top of the atmosphere (TOA) is-0.45 ... Direct climate responses to dust shortwave and longwave radiative forcing (RF) are studied using the NCAR Community Atmosphere Model Version 3 (CAM3). The simulated RF at the top of the atmosphere (TOA) is-0.45 W m-2 in the solar spectrum and +0.09 W m-2 in the thermal spectrum on a global average. The magnitude of surface RF is larger than the TOA forcing, with global mean shortwave forcing of-1.76 W m-2 and longwave forcing of +0.31 W m-2 . As a result, dust aerosol causes the absorption of 1.1 W m-2 in the atmosphere. The RF of dust aerosol is predicted to lead to a surface cooling of 0.5 K over the Sahara Desert and Arabian Peninsula. In the meantime, the upper troposphere is predicted to become warmer because of the absorption by dust. These changes in temperature lead to a more stable atmosphere, which results in increases in surface humidity. The upward sensible and latent heat fluxes at the surface are reduced, largely balancing the surface energy loss caused by the backscattering and absorption of dust aerosol. Precipitation is predicted to decrease moderately on a global scale. 展开更多
关键词 dust aerosol radiative forcing direct radiative effect general circulation model
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Correlation of Direct Piezoelectric Effect on EAPap under Ambient Factors 被引量:1
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作者 Li-Jie Zhao Chang-Ping Tang Peng Gong 《International Journal of Automation and computing》 EI 2010年第3期324-329,共6页
Direct piezoelectricity of electro-active papers (EAPap) is analysed in this paper. The test setups for direct effect are designed and determined. Different ambient factors impacting the piezoelectricity of EAPap, s... Direct piezoelectricity of electro-active papers (EAPap) is analysed in this paper. The test setups for direct effect are designed and determined. Different ambient factors impacting the piezoelectricity of EAPap, such as temperature, humidity, and strain rate, are applied and analyzed. Strong piezoelectricity of EAPap is found on the basis of the test results and in comparison with polyvinylidene fluoride (PVDF) and lead zirconate titanate (PZT)-5H. The maximum piezoelectric constant is achieved to be 504 pC/N. The reason of strong piezoelectricity of EAPap is discussed in this paper. The potential of EAPap as a biomimetic actuator and sensor is also investigated. 展开更多
关键词 Electro-active-polymer (EAP) electro-active papers (EAPap) biomimetic actuator PIEZOELECTRICITY direct piezoelectric effect.
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All-Sky Direct Radiative Effects of Urban Aerosols in Beijing and Shanghai, China 被引量:3
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作者 SHAO Si-Ya ZHANG Jing 《Atmospheric and Oceanic Science Letters》 CSCD 2015年第5期295-300,共6页
Aerosol particles can directly alter the radiation balance by scattering and absorbing incident solar radiation, thus decreasing the amount of light reaching the surface and increasing the fraction of diffuse radiatio... Aerosol particles can directly alter the radiation balance by scattering and absorbing incident solar radiation, thus decreasing the amount of light reaching the surface and increasing the fraction of diffuse radiation—the so-called ‘aerosol direct radiative effect'. Using the Moderate Resolution Imaging Spectroradiometer aerosol products, the aerosol direct radiative effects under all-sky conditions in Beijing and Shanghai in 2007 were explored in this study. The total shortwave radiation was calculated using the Fu-Liou radiative transfer model, with the influence of clouds taken into account through sunshine-duration data, and the diffuse radiation was calculated with radiation decomposition models. Good correlation between measured and calculated total radiation was obtained at both cities, with an R greater than 0.9, and thus this calculation method was adopted to derive aerosol direct radiative effects. The presence of aerosols caused the mean total and diffuse solar radiation reaching the surface to change by-19.9% and +27.4% in Beijing, respectively, and by-18.4% and +6.5% in Shanghai. It was also found that, despite the strong negative correlation between aerosol optical depth and total radiation change, the diffuse radiation changes were determined predominantly by clouds. The effects of such changes induced by aerosols on plant productivity should be further studied. 展开更多
关键词 AEROSOL direct RADIATIVE effect DIFFUSE radiation
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BOUNDS ON AVERAGE CONTROLLED DIRECT EFFECTS WITH AN UNOBSERVED RESPONSE VARIABLE 被引量:1
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作者 Na SHAN Jianhua GUO 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2011年第6期1154-1164,共11页
这份报纸考虑在一般水准上估计界限的问题面对在一个中间的变量和反应变量之间的未被遵守的 confounders 在一个未被遵守的反应变量上控制了一个处理变量的直接效果(ACDE ) 。当反应变量被观察时,蔡,等(2008 ) 在 ACDE 上为锋利的界... 这份报纸考虑在一般水准上估计界限的问题面对在一个中间的变量和反应变量之间的未被遵守的 confounders 在一个未被遵守的反应变量上控制了一个处理变量的直接效果(ACDE ) 。当反应变量被观察时,蔡,等(2008 ) 在 ACDE 上为锋利的界限导出公式。当反应变量是未被遵守的时,作者为选择反应变量假装在 ACDE 上为界限导出公式的变量建议一个图形的标准,它是 Kuroki (2005 ) 的结果的延期到 ACDE。结果使我们能不仅当反应变量是未被遵守的时,从图结构判定 ACDE 上的界限是否能通过观察变量被表示,而且当答案肯定时,提供他们的公式。 展开更多
关键词 平均控制 应变量 观测 边界问题 中间变量 图形结构 公式 图形化
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Direct Climatic Effect of Aerosols and Interdecadal Variations over East Asia Investigated by a Regional Coupled Climate-Chemistry/Aerosol Model 被引量:5
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作者 HAN Zhi-Wei XIONG Zhe LI Jia-Wei 《Atmospheric and Oceanic Science Letters》 2011年第6期299-303,共5页
The direct climatic effect of aerosols for the 1980-2000 period over East Asia was numerically investigated by a regional scale coupled climate-chemistry/aerosol model,which includes major anthropogenic aerosols(sulfa... The direct climatic effect of aerosols for the 1980-2000 period over East Asia was numerically investigated by a regional scale coupled climate-chemistry/aerosol model,which includes major anthropogenic aerosols(sulfate,black carbon,and organic carbon) and natural aerosols(soil dust and sea salt) .Anthropogenic emissions used in model simulation are from a global emission inventory prepared for the Intergovernmental Panel on Climate Change Fifth Assessment Report(IPCC AR5) ,whereas natural aerosols are calculated online in the model.The simulated 20-year average direct solar radiative effect due to aerosols at the surface was estimated to be in a range of-9--33 W m-2 over most areas of China,with maxima over the Gobi desert of West China,and-12 W m-2 to-24 W m-2 over the Sichuan Basin,the middle and lower reaches of the Yellow River and the Yangtze River.Aerosols caused surface cooling in most areas of East Asia,with maxima of-0.8-C to-1.6-C over the deserts of West China,the Sichuan Basin,portions of central China,and the middle reaches of the Yangtze River. Aerosols induced a precipitation decrease over almost the entire East China,with maxima of-90 mm/year to-150 mm/year over the Sichuan Basin,the middle reaches of the Yangtze River and the lower reaches of the Yellow River.Interdecadal variation of the climate response to the aerosol direct radiative effect is evident,indicating larger decrease in surface air temperature and stronger perturbation to precipitation in the 1990s than that in the 1980s,which could be due to the interdecadal variation of anthropogenic emissions. 展开更多
关键词 年代际变化 东亚气候 气溶胶 区域耦合 L模型 中国西部 长江中游 四川盆地
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Simulation of the Direct Radiative Effect of Mineral Dust and Sea Salt Aerosols in a Doubled Carbon Dioxide Climate 被引量:2
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作者 YUE Xu LIAO Hong TANG Jin-Ping 《Atmospheric and Oceanic Science Letters》 CSCD 2013年第5期343-348,共6页
The authors examine the equilibrium climatic response to the direct radiative effect(DRE)of mineral dust and sea salt aerosols in a doubled-CO2climate with two-way coupling of aerosol-climate interactions.In response ... The authors examine the equilibrium climatic response to the direct radiative effect(DRE)of mineral dust and sea salt aerosols in a doubled-CO2climate with two-way coupling of aerosol-climate interactions.In response to the drier and windier conditions,dust emissions increase by 26%in the Sahara Desert and by 18%on the global scale relative to present day.Sea salt emissions increase in high latitudes(>60°)but decrease in middle latitudes(30°–60°)of both hemispheres due to the poleward shift of westerlies,leading to a 3%decrease in global emissions.The burdens of dust and sea salt increase by 31%and 7%respectively,because reductions in rainfall over the tropical oceans increase the lifetime of particles in the warmer climate.The higher aerosol loading in the doubled-CO2climate reinforces aerosol DRE by0.2 W m 2,leading to an additional cooling of 0.1°C at the surface compared with the climatic effects of aerosols in present day.The additional cooling from changes in natural aerosols compensates for up to 15%of the regional warming induced by doubled CO2. 展开更多
关键词 矿物气溶胶 气候响应 二氧化碳 辐射效应 海盐 CO2浓度倍增 模拟 温室气体排放
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Regional Oceanic Impact on Circulation and Direct Radiative Effect of Aerosol over East Asia 被引量:1
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作者 XIONG Zhe HAN Zhi-Wei 《Atmospheric and Oceanic Science Letters》 2011年第6期324-329,共6页
The Regional Integrated Environmental Model System(RIEMS 2.0) coupled with a chemistry-aerosol model and the Princeton Ocean Model(POM) is employed to simulate regional oceanic impact on atmospheric circulation and th... The Regional Integrated Environmental Model System(RIEMS 2.0) coupled with a chemistry-aerosol model and the Princeton Ocean Model(POM) is employed to simulate regional oceanic impact on atmospheric circulation and the direct radiative effect(DRE) of aerosol over East Asia.The aerosols considered in this study include both major anthropogenic aerosols(e.g.,sulfate,black carbon,and organic carbon) and natural aerosols(e.g.,soil dust and sea salt) .The RIEMS 2.0 is driven by NCEP/NCAR reanalysis II,and the simulated period is from 1 January to 31 December 2006.The results show the following:(1) The simulated annual mean sea-level pressure by RIEMS 2.0 with POM is lower than without POM over the mainland and higher without POM over the ocean.(2) In summer,the subtropical high simulated by RIEMS 2.0 with POM is stronger and extends further westward,and the continental low is stronger than without POM in summer.(3) The aerosol optical depth(AOD) simulated by RIEMS 2.0 with POM is larger in the middle and lower reaches of the Yangtze River than without POM.(4) The direct radiative effect with POM is stronger than that without POM in the middle and lower reaches of the Yangtze River and parts of southern China. Therefore,the authors should take account of the impact of the regional ocean model on studying the direct climate effect of aerosols in long term simulation. 展开更多
关键词 气溶胶光学厚度 海洋模型 辐射效应 东亚地区 流通 区域海洋模式 模型系统 POM
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Seismic hazard assessment of Tehran,Iran with emphasis on near-fault rupture directivity effects
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作者 Ehsan Bazarchi Reza Saberi Majid Alinejad 《Earthquake Science》 CSCD 2018年第1期1-11,共11页
Many destructive earthquakes happened in Tehran, Iran in the last centuries. The existence of active faults like the North Tehran is the main cause of seismicity in this city. According to past investigations, it is e... Many destructive earthquakes happened in Tehran, Iran in the last centuries. The existence of active faults like the North Tehran is the main cause of seismicity in this city. According to past investigations, it is estimated that in the scenario of activation of the North Tehran fault, many structures in Tehran will collapse. Therefore, it is necessary to incorporate the near field rupture directivity effects of this fault into the seismic hazard assessment of important sites in Tehran. In this study, using calculations coded in MATLAB, Probabilistic Seismic Hazard Analysis (PSHA) is conducted for an important site in Tehran. Following that, deaggregation technique is performed on PSHA and the contribution of seis- mic scenarios to hazard is obtained in the range of distance and magnitude. After identifying the North Tehran fault as the most hazardous source affecting the site in 10000-year return period, rupture directivity effects of this fault is incorporated into the seismic hazard assessment using Somerville et al. (1997) model with broadband approach and Shahi and Baker (2011) model with narrowband approach. The results show that the narrowband approach caused a 27% increase in the peak of response spectrum in 10000-year return period compared with the conventional PSHA. Therefore, it is necessary to incorporate the near fault rupture directivity effects into the higher levels of seismic hazard assessment attributed to important sites. 展开更多
关键词 Probabilistic seismic hazard analysis North Tehran fault rupture directivity effect DEAGGREGATION controlling earthquake
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Direct Radiative Forcing and Climatic Effects of Aerosols over East Asia by RegCM3 被引量:2
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作者 JU Li-Xia HAN Zhi-Wei 《Atmospheric and Oceanic Science Letters》 2011年第6期363-367,共5页
The authors used a high-resolution regional climate model(RegCM3) coupled with a chemistry/aerosol module to simulate East Asian climate in 2006 and to test the climatic impacts of aerosols on regionalscale climate.Th... The authors used a high-resolution regional climate model(RegCM3) coupled with a chemistry/aerosol module to simulate East Asian climate in 2006 and to test the climatic impacts of aerosols on regionalscale climate.The direct radiative forcing and climatic effects of aerosols(dust,sulfate,black carbon,and organic carbon) were discussed.The results indicated that aerosols generally produced negative radiative forcing at the top-of-the-atmosphere(TOA) over most areas of East Asia.The radiative forcing induced by aerosols exhibited significant seasonal and regional variations,with the strongest forcing occurring in summer.The aerosol feedbacks on surface air temperature and precipitation were clear.Surface cooling dominated features over the East Asian continental areas,which varied in the approximate range of-0.5 to-2°C with the maximum up to-3-C in summer over the deserts of West China.The aerosols induced complicated variations of precipitation.Except in summer,the rainfall generally varied in the range of-1 to 1 mm d-1 over most areas of China. 展开更多
关键词 直接辐射强迫 东亚地区 气候效应 气溶胶 区域气候模式 表面冷却 中国西部 高分辨率
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Simulating Aerosol Optical Depth and Direct Radiative Effects over the Tibetan Plateau with a High-Resolution CAS FGOALS-f3 Model
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作者 Min ZHAO Tie DAI +4 位作者 Hao WANG Qing BAO Yimin LIU Hua ZHANG Guangyu SHI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2022年第12期2137-2155,I0020-I0022,共22页
Current global climate models cannot resolve the complex topography over the Tibetan Plateau(TP)due to their coarse resolution.This study investigates the impacts of horizontal resolution on simulating aerosol and its... Current global climate models cannot resolve the complex topography over the Tibetan Plateau(TP)due to their coarse resolution.This study investigates the impacts of horizontal resolution on simulating aerosol and its direct radiative effect(DRE)over the TP by applying two horizontal resolutions of about 100 km and 25 km to the Chinese Academy of Sciences Flexible Global Ocean-Atmosphere Land System(CAS FGOALS-f3)over a 10-year period.Compared to the AErosol RObotic NETwork observations,a high-resolution model(HRM)can better reproduce the spatial distribution and seasonal cycles of aerosol optical depth(AOD)compared to a low-resolution model(LRM).The HRM bias and RMSE of AOD decreased by 0.08 and 0.12,and the correlation coefficient increased by 0.22 compared to the LRM.An LRM is not sufficient to reproduce the aerosol variations associated with fine-scale topographic forcing,such as in the eastern marginal region of the TP.The difference between hydrophilic aerosols in an HRM and LRM is caused by the divergence of the simulated relative humidity(RH).More reasonable distributions and variations of RH are conducive to simulating hydrophilic aerosols.An increase of the 10-m wind speed in winter by an HRM leads to increased dust emissions.The simulated aerosol DREs at the top of the atmosphere(TOA)and at the surface by the HRM are–0.76 W m^(–2)and–8.72 W m^(–2)over the TP,respectively.Both resolution models can capture the key feature that dust TOA DRE transitions from positive in spring to negative in the other seasons. 展开更多
关键词 Tibetan Plateau high-resolution climate model aerosol optical depth aerosol direct radiative effect
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Analysis of nonlinearities and effects in direct drive electro-hydraulic position servo system 被引量:2
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作者 王洪杰 季天晶 +1 位作者 毛新涛 刘全忠 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2005年第1期6-10,共5页
The direct drive electro-hydraulic servo system is a new approach hydraulic system. It is much smaller and easier controlled than traditional systems and is a perfect energy saver. This paper will briefly introduce th... The direct drive electro-hydraulic servo system is a new approach hydraulic system. It is much smaller and easier controlled than traditional systems and is a perfect energy saver. This paper will briefly introduce the popular nonlinearities in the electro-hydraulic system and analyse the effect of nonlinearities in direct drive electro-hydraulic position servo system by means of simulation research. Some valuable conclusions are given. 展开更多
关键词 非线性特征 数学模型 直接驱动电子水压伺服系统 调节器 控制系统
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Study on the effect of ground motion direction on the response of engineering structure 被引量:1
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作者 Sun Menghan Fan Feng +1 位作者 Sun Baitao Zhi Xudong 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2016年第4期649-656,共8页
Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on... Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on a structure are studied herein. Ground motion records usually contain three vertical ground motion data, which are obtained by sensors arranged in accordance with the EW (East -West) direction, NS (South- North) direction and perpendicular to the surface (z) direction, referring to the construction standard of seismic stations. The seismic records in the EW and NS directions are converted to Cartesian coordinates in accordance with the rotation of θ = 0°-180°, and consequently, a countless group of new ground motion time histories are obtained. Then, the characteristics of the ground motion time history and response spectrum of each group were studied, resulting in the following observations: (1) the peak and phase of ground motion are changed with the rotation of direction θ, so that the direction θ of the maximum peak ground motion can be determined; (2) response spectrum values of each group of ground motions change along with the direction θ, and their peak, predominant period and declining curve are also different as the changes occur; then, the angle θ in the direction of the maximum peak value or the widest predominant period can be determined; and (3) the seismic response of structures with different directions of ground motion inputs has been analyzed under the same earthquake record, and the results show the difference. For some ground motion records, such as the Taft seismic wave, these differences are significant. Next, the Lushan middle school gymnasium structure was analyzed and the calculation was checked using the proposed method, where the internal force of the upper space truss varied from 25% to 28%. The research results presented herein can be used for reference in choosing the ground motion when checking the actual damage to structures following earthquakes and explaining the seismic damage. Meanwhile, it also provides a reference value for research into the most severe ground motion. 展开更多
关键词 direction of grotmd motion structure effect coordinate transformation response spectrum
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Nonideal effects in quantum field-effect directional coupler
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作者 谢月娥 颜晓红 陈元平 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第10期2415-2421,共7页
The nonideal effects in a quantum field-effect directional coupler where two quantum wires are coupled through a finite potential barrier are studied by adopting the lattice Green function method. The results show tha... The nonideal effects in a quantum field-effect directional coupler where two quantum wires are coupled through a finite potential barrier are studied by adopting the lattice Green function method. The results show that the electron energy distribution, asymmetric geometry and finite temperature all have obvious influence on the electron transfer of the coupler. Only for the electrons with energies in a certain region, can the complete periodic transfer between two quantum wires take place. The conductance of these electrons as a function of the barrier length and potential height exhibits a fine periodic or quasi-periodic pattern. For the electrons with energies beyond the region, however, the complete periodic transfer does not hold any more since many irregular oscillations are superimposed on the conductance profile. In addition, the finite temperature and asymmetric geometry both can reduce the electron transfer efficiency. 展开更多
关键词 nonideal effects directional coupler Green function
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Effects of Tensor Couplings on Nucleonic Direct URCA Processes in Neutron Star Matter
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作者 许妍 黄修林 +2 位作者 刘承志 特木尔巴根 刘广洲 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第9期132-135,共4页
The relativistic neutrino emissivity of the nucleonic direct URCA processes in neutron star matter is investigated within the relativistic Hartree-Fock approximation. We particularly study the influences of the tensor... The relativistic neutrino emissivity of the nucleonic direct URCA processes in neutron star matter is investigated within the relativistic Hartree-Fock approximation. We particularly study the influences of the tensor couplings of vector mesons ω and ρ on the nucleonic direct URCA processes. It is found that the inclusion of the tensor couplings of vector mesons w and p can slightly increase the maximum mass of neutron stars. In addition, the results indicate that the tensor couplings of vector mesons ω and ρ lead to obvious enhancement of the total neutrino emissivity for the nucleonic direct URCA processes, which must accelerate the cooling rate of the non- superfluid neutron star matter. However, when considering only the tensor coupling of vector meson ρ, the neutrino emissivity for the nucleonic direct URCA processes slightly declines at low densities and significantly increases at high densities. That is, the tensor coupling of vector meson ρ leads to the slow cooling rate of a low-mass neutron star and rapid cooling rate of a massive neutron star. 展开更多
关键词 of is it for effects of Tensor Couplings on Nucleonic direct URCA Processes in Neutron Star Matter in on
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ANALYSIS OF SIZE EFFECT,SHEAR DEFORMATION AND DILATION IN DIRECT SHEAR TEST BASED ON GRADIENT- DEPENDENT PLASTICITY 被引量:11
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作者 WangXuebin TangJupeng ZhangZhihui PanYishan 《岩石力学与工程学报》 EI CAS CSCD 北大核心 2004年第7期1095-1099,共5页
The paper concerns the issue of size law,localized deformation and dilation or compaction due to shear localization. It is assumed that the shear localization initiates at the peak shear stress in the form of single s... The paper concerns the issue of size law,localized deformation and dilation or compaction due to shear localization. It is assumed that the shear localization initiates at the peak shear stress in the form of single shear band,and based on gradient-dependent plasticity,an analytical solution on size effect or snap-back is obtained. The results show that the post peak response becomes steeper and even exhibits snap-back with increasing of length. For small specimen,the relative shear displacement when specimen failure occurs is lower than that of larger specimen and the shear stress-relative displacement curve becomes steeper. The theoretical solution on non-uniformity of strains in shear band is obtained and evolution of the relative shear displacement is represented. By resorting to the linear relation between local plastic shear strain and local plastic volumetric strain,the dilation and compaction within shear band are analyzed. Relation between apparent shear strain and apparent normal strain and relation between shear displacement and vertical displacement are established. 展开更多
关键词 应变梯度塑性理论 剪切试验 剪切变形 尺寸效应
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EFFECT OF HYDROGEN BONDING ON DIRECTION OF PHOTOISOMERIZATION OF RETINOIDS:THE ORIGIN OF THE SOLVENT POLARITY EFFECT.
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作者 Bao-wen ZHANG Robert S.H.LIU Department of Chemistry,2545 The Mall University of Hawaii,Honolulu,HI 96822 U.S.A. 《Chinese Chemical Letters》 SCIE CAS CSCD 1991年第1期9-12,共4页
Studies of direction of photoisomerization of retinal,retinonitrile,a- retinonitrile and a trienenitrile analog in different solvents with varying wave- lengths of excitation and reaction temperature led to the conclu... Studies of direction of photoisomerization of retinal,retinonitrile,a- retinonitrile and a trienenitrile analog in different solvents with varying wave- lengths of excitation and reaction temperature led to the conclusion that the well known solvent dependent photochemistry of retinoids is due to selective excitation of the hydrogen bonded species. 展开更多
关键词 effect OF HYDROGEN BONDING ON directION OF PHOTOISOMERIZATION OF RETINOIDS
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