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Character of Convective Systems Producing Short-Term Heavy Precipitation in Central China Revealed by Kilometer and Minute Interval Observations

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Journal of Meteorological Research 2024年第3期38卷 530-541页

作者： zitong chen Yunying LI Zhiwei ZHANG Jing SUN chengzhi YE Anyuan XIONG College of Meteorology and Oceanography National University of Defense Technology High Impact Weather Key Laboratory of China Meteorological Administration Unit No.92192 of Chinese People's Liberation Army Hubei Key Research Laboratory for Heavy Rain Monitoring and Warning Institute of Heavy RainChina Meteorological Administration Institute of Meteorological Sciences of Hunan Province Hunan Meteorological Bureau National Meteorological Information Centre China Meteorological Administration

Accurate forecasting of heavy precipitation in central China is still a challenge, within which a key issue is our still incomplete understanding of the convective systems（CSs） responsible for such events. In this study, through use of an iterative rain-cell tracking algorithm, the macroscale characteristics（scale, intensity, duration, etc.） of the CSs that produced 595 short-term heavy precipitation events in Hunan Province, central China, are quantitatively analyzed,based on radar reflectivity, echo top, and rainfall observations at 1-km and 6-min intervals in April–September of2016–2018. The results show that CSs present significant seasonal and diurnal features. Spring CSs usually cover a larger echo area with stronger convective cores and thus generate more precipitation than summer CSs, though summer CSs develop more vigorously and frequently. CSs initiated at 1400–1600 local time are characterized by the strongest convection and a smaller spatiotemporal scale, causing violent and transient showers with typical areal precipitation of 0.5–1mm km-2, but less total precipitation. Further analyses of the relationships among the scale, intensity, duration, and total precipitation of CSs reveal that the convective intensity is linearly correlated to the spatiotemporal scale of CSs, with the duration increasing on average by 0.0372 h dBZ-1; the echo area is significantly correlated to the total precipitation, and the duration and rainfall amount are connected with the area expansion rate（AER）of CSs: when the AER exceeds 50%, CSs expand rapidly with increasing total precipitation, but the duration is shorter.These findings provide a helpful reference for the forecasting of short-term heavy precipitation induced by CSs in central China.

关键词： convective system radar reflectivity factor total precipitation iterative rain-cell tracking

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Effects of forsythin extract in Forsythia leaves on intestinal microbiota and short-chain fatty acids in rats fed a high-fat diet

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Food Science and Human Wellness 2024年第2期13卷 659-667页

作者： Lanlan Gui Shaokang Wang Jing Wang Wang Liao zitong chen Da Pan Hui Xia Guiju Sun Su Tian Department of Nutrition and Food Hygiene School of Public HealthSoutheast UniversityNanjing 210009China Nanjing Municipal Center for Disease Control and Prevention Nanjing 210003China Department of Nutrition and Food Hygiene School of Public HealthHebei Medical UniversityShijiazhuang 050017China

Forsythia suspensa,belonging to the deciduous shrubs of the Luteaceae family,a traditional Chinese medicine,has effects of alleviating swelling,clearing heat,detoxification and promoting blood circulation.The leaves of F.suspensa contain multiple chemical components and have a long history of use in folk medicines and health foods.The purpose of this study was to explore the effects of forsythin extract from F.suspensa leaves on intestinal microbiota and short-chain fatty acid(SCFA)content in rats with obesity induced by a high-fat diet.Forsythin extract in F.suspensa leaves increased the abundance of the intestinal microbiota,ameliorated intestinal microbiota disorders and inhibited the increase in total SCFA content in the intestinal tract in rats with obesity induced by a high-fat diet.These results suggested that forsythin extract in F.suspensa leaves may slow the development of obesity induced by a high-fat diet;thus,its active components and efficacy are worthy of further study.

关键词： Forsythin High-fat diet Intestinal microbiota Short-chain fatty acid(SCFA)

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Preliminary Model Study for Forecasting a Hot Weather Process in Guangdong Province Using CMA-TRAMS

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Atmospheric and Climate Sciences 2024年第1期14卷 101-117页

作者： Wenfan Wang Jiemin Zhan Dehui chen zitong chen Yanxia Zhang Qing Fan Guangfeng Dai Yingying Luo Aifen Ye Department of Applied Mechanics and Engineering Shenzhen Campus of Sun Yat-sen University Shenzhen Guangdong China Guangzhou Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction CMA Guangzhou China

In this paper, the CMA-TRAMS tropical high-resolution system was used to forecast a typical hot weather process in Guangdong, China with different horizontal resolutions and surface coverage. The results of resolutions of 0.02° and 0.06° were presented with the same surface coverage of the GlobeLand30 V2020, companies with the results of resolution 0.02° with the USGS global surface coverage. The results showed that, on the overall assessment the 2 km model performed better in forecasting 2 m temperature, while the 6 km model was more accurate in predicting 10 m wind speed. In the evaluation of representative stations, the 2 km model performed better in forecasting 2 m temperature and 2 m relative humidity at the coastal stations, and the 2 km model was also better in forecasting 2 m pressure at the representative stations. However, the 6 km model performed better in forecasting 10 m wind speed at the representative stations. Furthermore, the 2 km model, owing to its higher horizontal resolution, presented a more detailed stratification of various meteorological field maps, allowing for a more pronounced simulation of local meteorological element variations. And the use of the surface coverage data of the GlobeLand30 V2020 improved the forecasting of 2 m temperature, and 10 m wind speed compared to the USGS surface coverage data.

关键词： High-Resolution Numerical Model CMA-TRAMS Model Test Evaluation Surface Coverage Numerical Simulation

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Decompositions of the Kadomtsev-Petviashvili equation and their symmetry reductions

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Chinese Physics B 2024年第3期33卷 150-159页

作者：陈孜童贾曼郝夏芝楼森岳 School of Mathematics and Statistics Ningbo UniversityNingbo 315211China School of Physical Science and Technology Ningbo UniversityNingbo 315211China College of Science Zhejiang University of TechnologyHangzhou 310014China

Starting with a decomposition conjecture,we carefully explain the basic decompositions for the Kadomtsev-Petviashvili(KP)equation as well as the necessary calculation procedures,and it is shown that the KP equation allows the Burgers-STO(BSTO)decomposition,two types of reducible coupled BSTO decompositions and the BSTO-KdV decomposition.Furthermore,we concentrate ourselves on pointing out the main idea and result of Bäcklund transformation of the KP equation based on a special superposition principle in the particular context of the BSTO decompositions.Using the framework of standard Lie point symmetry theory,these decompositions are studied and the problem of computing the corresponding symmetry constraints is treated.

关键词： Kadomtsev-Petviashvili(KP)equation decomposition Bäcklund transformation symmetry reduction

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Regioselectivity of Pd-catalyzed o-carboranearylation: a theoretical view

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Organic Chemistry Frontiers 2022年第6期9卷 1686-1695页

作者： Jiying Liu Dongmin Fu zitong chen Tiantian Li Ling-Bo Qu Shi-Jun Li Wenjing Zhang Yu Lan Green Catalysis Center and College of ChemistryZhengzhou UniversityZhengzhouHenan 450001China School of Chemistry and Chemical Engineering and Chongqing Key Laboratory of Theoretical and Computational ChemistryChongqing UniversityChongqing 400030China

The mechanism and the regioselectivity of Pd-catalyzed B(4)–H arylation and B(4,5)–H diarylation foro-carborane with bidentate directing groups were investigated. The complete catalytic cycle involves Pdmediated concerted metalation–deprotonation, oxidative addition, counterion exchange, and reductiveelimination, where counterion exchange is critical. The reductive elimination is the rate- and regioselectivity-determining step for the whole catalytic cycle. B(3)-Arylation is unfavorable because the stericrepulsion between the substituent group on C(2) and the metal moiety would lead to significant distortionof o-carborane and would result in a higher activation energy for reductive elimination. The distortion ofo-carborane can be clearly observed from the change of its aromaticity in the corresponding transitionstates by the calculation of nucleus-independent chemical shifts. Moreover, counterion exchange withcarboxylate before reductive elimination significantly increases the positive charge of palladium, whichleads to a lower activation free energy for the sequential step.

关键词： elimination catalyzed reductive

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Novel travelling wave structures:few-cyclepulse solitons and soliton molecules

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Communications in Theoretical Physics 2021年第2期73卷 23-29页

作者： zitong chen Man Jia School of Physical Science and Technology Ningbo UniversityNingbo 315211China

We discuss a fifth order KdV(FOKdV)equation via a novel travelling wave method by introducing a background term.Results show that the background term plays an essential role in finding new abundant travelling wave structures,such as the soliton induced by negative background,the periodic travelling wave excited by the positive background,the few-cycle-pulse(FCP)solitons with and without background,the soliton molecules excited by the background.The FCP solitons are first obuained for the FOKdV equation.

关键词： New travelling method a fifth order KdV equation solitons induced by background few-cycle-pulse solitons soliton molecules

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Evaluating and Improving Wind Forecasts over South China: The Role of Orographic Parameterization in the GRAPES Model

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Advances in Atmospheric Sciences 2018年第6期35卷 713-722页

作者： Shuixin ZHONG zitong chen Daosheng XU Yanxia ZHANG Guangdong Province Key Laboratory of Regional Numerical Weather Prediction Institute of Tropical and Marine MeteorologyChina Meteorological Administration

Unresolved small-scale orographic（SSO） drags are parameterized in a regional model based on the Global/Regional Assimilation and Prediction System for the Tropical Mesoscale Model（GRAPES TMM）. The SSO drags are represented by adding a sink term in the momentum equations. The maximum height of the mountain within the grid box is adopted in the SSO parameterization（SSOP） scheme as compensation for the drag. The effects of the unresolved topography are parameterized as the feedbacks to the momentum tendencies on the first model level in planetary boundary layer（PBL）parameterization. The SSOP scheme has been implemented and coupled with the PBL parameterization scheme within the model physics package. A monthly simulation is designed to examine the performance of the SSOP scheme over the complex terrain areas located in the southwest of Guangdong. The verification results show that the surface wind speed bias has been much alleviated by adopting the SSOP scheme, in addition to reduction of the wind bias in the lower troposphere. The target verification over Xinyi shows that the simulations with the SSOP scheme provide improved wind estimation over the complex regions in the southwest of Guangdong.

关键词： small-scale orographic drag GRAPES_TMM PBL parameterization wind bias

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Optimal location query based on k nearest neighbours

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Frontiers of Computer Science 2021年第2期15卷 105-117页

作者： Yubao LIU zitong chen Ada Wai-Chee FU Raymond Chi-Wing WONG Genan DAI School of Data and Computer Science Sun Yat-Sen UniversityGuangzhou510006China Guangdong Key Laboratory of Big Data Analysis and Processing Guangzhou510006China Department of Computer Science and Engineering Chinese University of Hong KongHong Kong999077China Department of Computer Science and Engineering The Hong Kong University of Science and TechnologyHong Kong999077China

Optimal location query in road networks is a basic operation in the location intelligence applications.Given a set of clients and servers on a road network,the purpose of optimal location query is to obtain a location for a new server,so that a certain objective function calculated based on the locations of clients and servers is optimal.Existing works assume no labels for servers and that a client only visits the nearest server.These assumptions are not realistic and it renders the existing work not useful in many cases.In this paper,we relax these assumptions and consider the k nearest neighbours(KNN)of clients.We introduce the problem of KNN-based optimal location query(KOLQ)which considers the k nearest servers of clients and labeled servers.We also introduce a variant problem called relocation KOLQ(RKOLQ)which aims at relocating an existing server to an optimal location.Two main analysis algorithms are proposed for these problems.Extensive experiments on the real road networks illustrate the efficiency of our proposed solutions.

关键词： optimal location query k nearest neighbours road network

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南海台风模式对台风利奇马快速增强预报能力研究

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气象 2024年第5期50卷 532-546页

作者：黄燕燕陈子通冯业荣张艳霞徐道生郑彬靳卫卫中国气象局广州热带海洋气象研究所/区域数值天气预报重点实验室广州510640 中海油能源发展股份有限公司安全环保分公司天津300452

针对台风利奇马(1909),分析中国气象局南海台风模式(CMA-TRAMS)和欧洲中期天气预报中心高分辨率模式(HRES)对台风快速增强的业务预报情况,并基于CMA-TRAMS,从水平分辨率、初始场和边界条件、物理参数化方案等角度设计并开展数值敏感性... 详细信息

针对台风利奇马(1909),分析中国气象局南海台风模式(CMA-TRAMS)和欧洲中期天气预报中心高分辨率模式(HRES)对台风快速增强的业务预报情况,并基于CMA-TRAMS,从水平分辨率、初始场和边界条件、物理参数化方案等角度设计并开展数值敏感性试验。CMA-TRAMS和HRES对“利奇马”增强具有一定预报能力,但对快速增强的速度预报明显低于实况,均不能满足24 h和12 h快速增强标准,可达到6 h快速增强标准。CMA-TRAMS采用3 km分辨率对“利奇马”移动路径和强度变化的预报效果优于9 km分辨率,但未改进快速增强预报效果;采用3 km嵌套9 km的方案,模式对台风快速增强的预报效果明显提升。采用MRF边界层参数化方案对台风路径、强度、快速增强的预报效果总体优于YSU方案。海温参数化结合32层垂直分辨率的初始场和边界条件的方案明显提高了快速增强预报效果,预报快速增强的频次、增强的最大速度更接近实况。分析表明,海温参数化方案使海气温差增大,在短时间内对大气、海洋之间的热量输送和交换有明显影响,海洋向大气输送的感热通量和台风内核区的潜热通量加强使内核更暖湿、气压负倾向增大,是预报效果改进的主要原因。

关键词：台风快速增强可预报性 CMA-TRAMS 数值模拟海温参数化方案

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基于高职院校畜牧兽医类专业岗位实习管理模式的实践与思考

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畜牧兽医杂志 2024年第3期43卷 82-84,87页

作者：李玩生宋世斌孙甲川陈姿彤马瑜甘肃农业职业技术学院甘肃兰州730020

基于高职院校畜牧兽医类专业岗位实习管理模式的实践,本文从岗位实习的组织、实习咨询及问题处理、安全保障、监督与抽查、管理中的突出问题及成因分析与优化途径方面进行了梳理与总结,并据此提出了加强信息共享,积极推进信息化管理;基... 详细信息

基于高职院校畜牧兽医类专业岗位实习管理模式的实践,本文从岗位实习的组织、实习咨询及问题处理、安全保障、监督与抽查、管理中的突出问题及成因分析与优化途径方面进行了梳理与总结,并据此提出了加强信息共享,积极推进信息化管理;基于“三全育人”理念,引导学生树立正确实习观念;持续推进规范化管理,建立长效机制的实施路径,以期为我国高职院校畜牧兽医类专业岗位实习管理模式提供借鉴。

关键词：畜牧兽医岗位实习三全育人管理模式

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