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Search Results: 1 - 10 of 24484 matches for " Jiang Zhihong "
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Theoretical Relationship between SSA and MESA with Both Application
Ding Yuguo,Jiang Zhihong,
Ding Yuguo
,Jiang Zhihong

大气科学进展 , 1998,
Abstract: I.INTRODUCTIONSingularspectralanalysis(SSA),asanewdiagnosticmethod,hasbenextensivelyappliedinclimaticdiagnosesandpredictionwi...
Association of North Atlantic Oscillations with Aksu River runoff in China

LI Hongjun,JIANG Zhihong,YANG Qing,

地理学报 , 2009,
Abstract: The relationship between North Atlantic Oscillations (NAO) and Aksu River Runoff (ARR) was investigated by using the wavelet transform (WT), cross wavelet transform (CWT), correlation and linear trend analyses, and abrupt change test. The main results are as follows: the interannual/decadal variation and period analyses of ARR and NAO reveal that the both were close correlated each other; the CWT indicates that the correlation was good between ARR and NAO at all periods in the 1990s, because the significant correlation areas mainly concentrated in the 1990s; the variations in the trend strength of ARR and NAO were consistent; the abrupt change of NAO was also temporally consistent with that of ARR, which exerted impact on the Aksu River Basin (ARB) climate and then the ARR through atmospheric circulation variation.
Univalent harmonic mappings and lift to the minimal surfaces
YuePing Jiang,ZhiHong Liu,Saminathan Ponnusamy
Mathematics , 2015,
Abstract: We construct sense-preserving univalent harmonic mappings which map the unit disk onto a domain which is convex in the horizontal direction, but with varying dilatation. Also, we obtain minimal surfaces associated with such harmonic mappings. This solves also a recent problem of Dorff and Muir (Abstr. Appl. Anal. (2014)). In several of the cases, we illustrate mappings together with their minimal surfaces pictorially with the help of \texttt{Mathematica} software.
A Newly-Discovered GPD-GEV Relationship Together with Comparing Their Models of Extreme Precipitation in Summer
DING Yuguo,CHENG Bingyan,JIANG Zhihong,
DING Yuguo
,CHENG Bingyan,JIANG Zhihong

大气科学进展 , 2008,
Abstract: It has been theoretically proven that at a high threshold an approximate expression for a quantile of GEV (Generalized Extreme Values) distribution can be derived from GPD (Generalized Pareto Distribu-tion). Afterwards, a quantile of extreme rainfall events in a certain return period is found using L-moment estimation and extreme rainfall events simulated by GPD and GEV, with all aspects of their results com-pared. Numerical simulations show that POT (Peaks Over Threshold)-based GPD is advantageous in its simple operation and subjected to practically no effect of the sample size of the primitive series, producing steady high-precision fittings in the whole field of values (including the high-end heavy tailed). In compari-son, BM (Block Maximum)-based GEV is limited, to some extent, to the probability and quantile simulation, thereby showing that GPD is an extension of GEV, the former being of greater utility and higher significance to climate research compared to the latter.
Research on the Influence of Political Correlation of Private Listed Companies on Corporate Social Responsibility Behavior  [PDF]
Zhihong Fu
American Journal of Industrial and Business Management (AJIBM) , 2019, DOI: 10.4236/ajibm.2019.93040
Based on the perspective of legitimacy, this paper uses the Logistic and OLS regression methods to analyze the relationship between the release of CSR reports issued by private companies from 2010 to 2016 and the relationship between report quality and executive political connections. The analysis shows that executive political relations can significantly affect the quality of private companies in the CSR report release and publication possibility of CSR report. According to the analysis results, the paper finally proposes how to promote corporate social responsibility by exerting the political correlation role of executives. Through theoretical and empirical research, it analyzes the influence of executive political association on corporate financial performance and social responsibility, and analyzes and verifies the role of regional marketization development process in private social responsibility behavior and political association formation motivation, thus making private enterprise politics rational use of related resources, standardizing and guiding the commitment of civil society’s social responsibility, and providing corresponding policy recommendations for promoting healthy and sustainable economic development. Secondly, this study analyzes the influence of executive political connections on corporate social responsibility behavior from a multi-theoretical perspective, and provides more analytical perspectives for future related research.
Large-scale atmospheric singularities and summer long-cycle droughts-floods abrupt alternation in the middle and lower reaches of the Yangtze River
Zhiwei Wu,Jianping Li,Jinhai He,Zhihong Jiang
Chinese Science Bulletin , 2006, DOI: 10.1007/s11434-006-2060-x
Abstract: The daily precipitation data at 720 stations over China for the 1957–2003 period during summer (May–August) are used to investigate the summer subseasonal long-cycle droughts-floods abrupt alternation (LDFA) phenomenon and a long-cycle droughts-floods abrupt alternation index (LDFAI) in the middle and lower reaches of the Yangtze River (MLYRV) is defined to quantify this phenomenon. The large-scale atmospheric circulation features in the anomalous LDFA years are examined statistically. Results demonstrate that the summer droughts-to-floods (DTF) in the MLYRV usually accompany with the more southward western Pacific subtropical high (WPSH), negative vorticity, strong divergence, descending movements developing and the weak moisture transport in the low level, the more southward position of the South Asia high (SAH) and the westerly jets in the high level during May–June, but during July–August it is in the other way, northward shift of the WPSH, positive vorticity, strong convergence, ascending movements and strong moisture transport in the low level, and the northward shift of the SAH and the westerly jets in the high level. While for the summer floods-to-droughts (FTD) in the MLYRV it often goes with the active cold air mass from the high latitude, positive vorticity, strong convergence, ascending movement developing and the strong moisture transport in the low level, and the SAH over the Tibetan Plateau in the high level, but during July–August it is often connected with the negative vorticity, strong divergence, descending movements developing and the weak moisture transport in the low level, the remarkable northward shift of the WPSH, the SAH extending northeastward to North China and the easterly jets prevailing in the high level over the MLYRV. In addition, the summer LDFA in the MLYRV is of significant relationship with the Southern Hemisphere annual mode and the Northern Hemisphere annual mode in the preceding February, which offers some predictive signals for the summer LDFA forecasting in the MLYRV.
“Climate effect” of the northeast cold vortex and its influences on Meiyu
JinHai He,ZhiWei Wu,ZhiHong Jiang,ChunSheng Miao,GuiRong Han
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0053-z
Abstract: The Northeast Cold Vortex (NECV) is an important weather system in the middle and high latitudes in East Asia. Its time scale is synoptic, yet the frequent activities of NECV have significant “climate effect” which influences not only the monthly temperature in the lower troposphere in Northeast China but also the Meiyu rainfall in East Asia. On the basis of ERA-40 reanalysis data provided by ECMWF, the “climate effect” of NECV and its relationship with Meiyu in East Asia are studied. It is shown that there is significant correlation between NECV during the Meiyu period and rainfall amount: strong NECV corresponds to more Meiyu rainfall and weak NECV corresponds to less rainfall. In strong NECV years, the dry and cold air from the north is led to the south by NECV, converges with the lower-level warm and wet southwesterly on the north verge of Meiyu region, thus forms an unstable stratification of “upper dryness and lower wetness”. Triggered by ascending motion, the Meiyu rainfall amount is more than usual. It is on the contrary in weak NECV years. The anomalous SST in north Pacific in the previous year may be a factor that results in the anomalous NECV at Meiyu period. The land-sea thermal contrast in summer facilitates NECV, while that in winter inhibits NECV. All of the above provide a meaningful result for the short-term climate prediction of NECV and Meiyu.
An Improved, Downscaled, Fine Model for Simulation of Daily Weather States

JIANG Zhihong,DING Yuguo,ZHENG Chunyu,CHEN Weilin,

大气科学进展 , 2011,
Abstract: In this study, changes in daily weather states were treated as a complex Markov chain process, based on a continuous-time watershed model (soil water assessment tool, SWAT) developed by the Agricultural Research Service at the U.S. Department of Agriculture (USDA-ARS). A finer classification using total cloud amount for dry states was adopted, and dry days were classified into three states: clear, cloudy, and overcast (rain free). Multistate transition models for dry- and wet-day series were constructed to comprehensively downscale the simulation of regional daily climatic states. The results show that the finer, improved, downscaled model overcame the oversimplified treatment of a two-weather state model and is free of the shortcomings of a multistate model that neglects finer classification of dry days (i.e., finer classification was applied only to wet days). As a result, overall simulation of weather states based on the SWAT greatly improved, and the improvement in simulating daily temperature and radiation was especially significant.
Crystal Structures of E. coli Native MenH and Two Active Site Mutants
Jodie M. Johnston, Ming Jiang, Zhihong Guo, Edward N. Baker
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061325
Abstract: Recent revision of the biosynthetic pathway for menaquinone has led to the discovery of a previously unrecognized enzyme 2-succinyl-6-hydroxy-2,4-cyclohexadiene-?1-carboxylatesynthase, also known as MenH. This enzyme has an α/β hydrolase fold with a catalytic triad comprising Ser86, His232, and Asp210. Mutational studies identified a number of conserved residues of importance to activity, and modeling further implicated the side chains of Tyr85 and Trp147 in formation of a non-standard oxyanion hole. We have solved the structure of E. coli MenH (EcMenH) at 2.75 ? resolution, together with the structures of the active site mutant proteins Tyr85Phe and Arg124Ala, both at 2.5 ? resolution. EcMenH has the predicted α/β hydrolase fold with its core α/β domain capped by a helical lid. The active site, a long groove beneath the cap, contains a number of conserved basic residues and is found to bind exogeneous anions, modeled as sulfate and chloride, in all three crystal structures. Docking studies with the MenH substrate and a transition state model indicate that the bound anions mark the binding sites for anionic groups on the substrate. The docking studies, and careful consideration of the active site geometry, further suggest that the oxyanion hole is of a conventional nature, involving peptide NH groups, rather than the proposed site involving Tyr85 and Trp147. This is in accord with conclusions from the structure of S. aureus MenH. Comparisons with the latter do, however, indicate differences in the periphery of the active site that could be of relevance to selective inhibition of MenH enzymes.
Dynamic Robertson's Platoon Dispersion Model in Connected Vehicle Environment

姚志洪, 蒋阳升
YAO Zhihong
, JIANG Yangsheng

- , 2018, DOI: 10.3969/j.issn.0258-2724.2018.02.023
Abstract: 传统Robertson车队离散模型参数估计是基于历史数据,不能很好地反映交通流的动态变化特征,为解决这一问题,构建了车联网环境下的动态Robertson车队离散模型.考虑到车联网环境下车辆的行程时间数据易于获得,基于此可对Robertson模型的相关参数进行实时动态估计建立动态Robertson车队流量离散模型.通过实际调查数据,分析了上游交叉口车辆离去流率与下游交叉口车辆到达流率的关系,并将文中模型与静态Robertson模型、实际观测数据进行了比较分析.结果表明,文中动态模型更能反映交通流的车队离散规律,与静态Robertson模型相比,平均预测均方误差减少了30.68%.
:The parameters of the traditional Robertson's platoon dispersion model are based on historical data, and thus, it cannot provide a good reflection of the dynamic characteristics of traffic flow. In order to solve this problem, a connected vehicle environment is considered, and the travel time of the vehicles is easily obtained. The relevant parameters of the Robertson's model can be estimated in real time based on this. Then, a dynamic Robertson's platoon dispersion model was proposed. Later, the relationship between the arrival flow rate of the downstream intersection and the departing flow rate of the upstream intersection was analysed using the proposed model with field collected data, and compared with those obtained using the traditional Robertson's model and actual data. The results show that the proposed model can better describe the law of dispersion in traffic flow, and the mean squared error of prediction is reduced by approximately 30.68%, compared with the traditional Robertson's model
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