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Influence of sea-land breeze on the formation and dissipation of severe dense fog and its burst reinforcement in the Yellow Sea coastal area,China

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Science China Earth Sciences 2024年第2期67卷 432-449页

作者： Ya GAO Duanyang LIU Shuqi YAN Wenjun ZHOU Hongbin WANG fan zu Qin MEI Chuanxiang YI Ye SHENG Key Laboratory of Transportation Meteorology of China Meteorological Administration Nanjing210041China Yancheng Meteorological Bureau Yancheng224000China Nanjing Joint Institute for Atmospheric Sciences Nanjing210041China Key Laboratory of Disaster Weather Chinese Academy of Meteorological SciencesBeijing100086China

Based on the global reanalysis data of the National Centers for Environmental Prediction(NCEP)/National Center for Atmospheric Research,the surface meteorological observation data,sounding data and satellite observation data,this paper comprehensively analyzes the evolution process and formation mechanism of a persistent severe dense fog process occurred on February 15–17,2015 in Yancheng,eastern *** the numerical simulation experiment of Weather Research and Forecast(WRF)model,we further analyze the impact of sea-land breeze on the formation and burst reinforcement of *** show that the precipitation caused by the southwesterly airflow in front of the upper-level trough and the low-pressure inverted trough are conducive to the formation of early rain fog,while the nighttime clear radiance under the control of surface cold high and the infiltration of weak cold advection are conducive to the formation and development of later radiation-advection *** WRF model simulates the fog evolution process,which is basically consistent with the actual fog area,and the simulation results are credible to a certain *** simulation results show that the establishment of sea breeze has an advection cooling effect on the near surface layer,which is conducive to the formation and development of the inversion layer on the near surface,providing stable stratification conditions for the formation and burst reinforcement of *** one hand,the strengthening of sea breeze circulation can continuously transport water vapor to the study *** the other,the occurrence of ultra-low level jet is favorable for the accumulation of low-level water *** the same time,the inversion intensity further strengthens,which is in favor of the burst reinforcement and long-term maintenance of fog.

关键词： Radiation-advection fog Sea-land breeze Atmospheric boundary layer Fog burst reinforcement WRF model

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不平衡电网电压下MMC-UPQC的无源超螺旋二阶滑模控制策略

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控制与决策 2024年第5期39卷 1487-1497页

作者：黄祖繁周建萍茅大钧齐国庆从帆平上海电力大学自动化工程学院上海200090

基于模块化多电平换流器(modular multilevel converter, MMC)的统一电能质量调节器(unified power quality conditioner, UPQC)在电网电压不平衡时,采用传统控制方法存在补偿效率和精确性较低的问题.针对这一情况,提出一种无源超螺旋... 详细信息

基于模块化多电平换流器(modular multilevel converter, MMC)的统一电能质量调节器(unified power quality conditioner, UPQC)在电网电压不平衡时,采用传统控制方法存在补偿效率和精确性较低的问题.针对这一情况,提出一种无源超螺旋二阶滑模控制策略.首先,基于MMC-UPQC的数学模型和无源控制理论,设计不平衡电网电压下基于欧拉-拉格朗日模型的正负序无源控制器;然后,加入超螺旋二阶滑模控制对无源控制器进行改善,抑制常规滑模存在的抖振,并解决无源控制对系统精度要求高的问题,提高系统的响应速度、补偿精度和抗干扰能力,提升系统的整体性能;最后,在Matlab/Simulink平台上进行仿真,并与PI控制和单独的无源控制对比,仿真结果验证了所提无源超螺旋二阶滑模控制策略的有效性和优越性.

关键词：模块化多电平换流器统一电能质量调节器电网电压不平衡无源超螺旋二阶滑模控制欧拉-拉格朗日模型

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接受背内侧丘脑投射的前额叶皮层锥体神经元的电生理学和形态学特性

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生理学报 2024年第2期76卷 233-246页

作者：范祖权陶晓冬魏亚茹张雪寒复旦大学脑科学研究院医学神经生物学国家重点实验室教育部脑科学前沿中心上海200032

脑高级功能对生物体的生存至关重要。内侧前额叶皮层(medial prefrontal cortex,mPFC)和背内侧丘脑(mediodorsal thalamus,MD)之间存在的密集交互投射在多种认知功能和执行功能的调控中发挥重要作用。根据神经元的形态学和电生理学特性,... 详细信息

脑高级功能对生物体的生存至关重要。内侧前额叶皮层(medial prefrontal cortex,mPFC)和背内侧丘脑(mediodorsal thalamus,MD)之间存在的密集交互投射在多种认知功能和执行功能的调控中发挥重要作用。根据神经元的形态学和电生理学特性,mPFC的锥体神经元已被分成多种亚类,但是特定神经环路的mPFC神经元的形态学和电生理学特性尚不清楚。本文旨在研究mPFC中接受MD投射的锥体神经元的形态学和电生理学特性。在过去,研究神经元的形态学和电生理学特性主要依赖大量的神经元电生理记录和其形态重构,但是在研究特定神经环路的神经元电生理和形态学特性时,这种方法效率较低。针对这一不足,本研究将传统形态学和电生理学方法与聚类分析等机器学习的方法相结合,建立mPFC锥体神经元形态学和电生理特性的分类模型。采用神经环路跨突触示踪策略标记mPFC中接受MD投射的锥体神经元,应用全细胞膜片钳记录和神经元重构技术获取mPFC中接受MD投射的锥体神经元的形态学特征。结果显示,本研究所建立的分类模型能够通过锥体神经元的形态预测其电生理特征。与mPFC中的非MD神经支配神经元相比,MD神经支配的mPFC锥体神经元表现出更大的基底树突长度,但顶端树突的复杂性更低。MD支配的mPFC锥体神经元的两种亚型(ET-1和ET-2)的形态特征不同,ET-1神经元的顶端树突比ET-2神经元更长、更复杂。本研究结果表明接受MD投射的mPFC锥体神经元的电生理特性与其形态学特征相关,提示接受MD投射的mPFC锥体神经元的两个电生理亚类在PFC局部回路以及PFC与其他皮层或皮层下脑区的环路中的作用不同。

关键词：锥体神经元前额叶皮层背内侧丘脑聚类分析神经元重构

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基于LSTM和先验知识的高速公路路面温度预报

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应用气象学报 2024年第1期35卷 68-79页

作者：熊国玉祖繁包云轩王可心南京信息工程大学气象灾害预报预警和评估协同创新中心南京210044 中国气象局交通气象重点开放实验室/南京气象科技创新研究院南京210009 无锡学院江苏省物联网设备超融合应用与安全工程研究中心无锡214105

为了精准预报高速公路路面温度,为车辆安全行驶提供气象保障,采用2019—2022年南京市绕城高速公路上9个交通气象站及ERA5-land再分析数据,通过构建时间序列特征工程、引入物理机制相关数据两类方法结合先验知识,运用长短期记忆神经网络... 详细信息

为了精准预报高速公路路面温度,为车辆安全行驶提供气象保障,采用2019—2022年南京市绕城高速公路上9个交通气象站及ERA5-land再分析数据,通过构建时间序列特征工程、引入物理机制相关数据两类方法结合先验知识,运用长短期记忆神经网络模型建立研究区域内4个交通气象站未来3 h逐10 min路面温度多步预报模型并进行验证;在此基础上,将已建立的模型应用于其他交通气象站,探究模型的适用性。结果表明:结合先验知识后,模型预报性能明显提高,准确率在85%以上,且随着预报时效的延长,性能提升更为明显,准确率最高提升36%;模型能较为准确地预报路面极端低温发生的时间和极值,且在预报时效较短时对路面极端高温的预报也具有一定参考价值;利用已建立的模型对其他交通气象站的路面温度进行预报时,准确率在62%以上,在预报时效较短时效果较好,准确率在80%以上,且交通气象站所处的下垫面背景类型对模型的选择起关键作用。

关键词：高速公路路面温度长短期记忆神经网络先验知识多步预报模型

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Joint transmit beamforming and power control in multi-user MIMO downlink using a game theoretic approach

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The Journal of China Universities of Posts and Telecommunications 2007年第2期14卷 14-18页

作者： ZENG Yi ZHANG zu-fan Special Research Center for Optical Intemet and Wireless Information Networks Chongqing University of Posts and Telecommunications Chongqing 400065 China

This study addresses the problem of jointly optimizing the transmit beamformers and power control in multi-user multiple-input multiple-output （MIMO） downlink. The objective is minimizing the total transmission power while satisfying the signal-to-noise plus interference ratio （SINR） requirement of each user. Before power control, it uses the maximum ratio transmission （MRT） scheme to determine the beamformers due to its attractive properties and the simplicity of handling. For power control it introduces a supermodular game approach and proposes an iterated strict dominance elimination algorithm. The algorithm is proved to converge to the Nash equilibrium. Simulation results indicate that this joint optimization method assures the improvement of performance.

关键词： multi-user MIMO power control transmit beamforming MRT supermodular game

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Particle size distribution and characteristics of polycyclic aromatic hydrocarbons during a heavy haze episode in Nanjing,China

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Particuology 2015年第1期13卷 127-134页

作者： Qingzi Meng Shuxian fan Jiabao He Jian Zhang Yu Sun Yue Zhang fan zu Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science and Technology Department of Atmospheric Physics Nanjing University of Information Science and Technology Jiangsu Institute of Meteorological Sciences

A heavy haze episode caused by agricultural burning occurred in Nanjing from November 7 to November 8, 2009. PM10 samples were collected on normal and hazy days from November I to November 14, 2009 at both city and suburban sites of Nanjing. Sixteen PAHs were measured during the day and at night. The results show that the concentrations of the particles were as high as 579.55 and 573.43 μg/m^3 during the haze episode at the city and suburban sites, respectively, 3-4 times higher than those on a normal day. The proportions of fine particles during the haze episode were also higher than those on a normal day. The changes in the concentrations of PAHs were in accordance with the concentrations of the particles. High- molecular-weight PAHs composed approximately 80% of the total PAHs on normal days and during the haze episode. The concentration of PAHs in fine fractions significantly increased during the haze episode, and this increase was most obvious at night at the city site, The proportion of total carcinogenic PAHs in fine particles was relatively high during the haze episode at both sampling sites, particularly at night at the city site.

关键词： Polycyclic aromatic hydrocarbons Agricultural burning Haze episode Particle size distribution Meteorological conditions Nanjing

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Analytical general results for handoff dwell time distribution in wireless networks

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The Journal of China Universities of Posts and Telecommunications 2006年第4期13卷 29-33页

作者： ZHANG zu-fan DU Hui-ping JIANG Ze University of Posts and Telecommunications Chongqing 400065 China University of Electronic Science and Technology of China Chengdu 610065 China

This article presents a general evaluation of handoff dwell time distribution based on geometric analysis methods. Considering the geometric characteristic of the deployed sector pattern, and the distribution of the users＇ position and the moving direction in the given sector, the general formulas of the probability density function of sector handoff dwell time are derived. Some numerical results are also presented for illustration.

关键词： wireless networks handoff dwell time probability density function

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High isolation dual-element modified PIFA array for MIMO application

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The Journal of China Universities of Posts and Telecommunications 2012年第3期19卷 1-6页

作者： LOU Si-yan LI Xiao-lin ZHANG zu-fan School of Communication and Information Engineering Chongqing University of Posts and Telecommunications Chongqing 400065 China Chongqing Information Technology Designing CO. LTD. Chongqing 400065 China

In this paper, we focus on antenna array design for mobile phone with finite volume and propose a novel antenna element structure by capacitive feeding and capacitive loading method based on the planar inverted F antenna （PIFA）. State-of-the-art development on this issue is reviewed. Then, a novel capacitively fed and capacitively loaded PIFA structure is proposed and studied. The results of the experiments showed that our structure can reduce the coupling of antenna elements from - 13.4 dB to -24.5 dB. Finally, a design with a bandwidth of 100 MHz centered at 2.35 GHz and envelopment correlation coefficient of 0.01 2 is provided and the diversity performance of the dual-element modified PIFA array is evaluated in both simulation and measurement. In a word, our novel design reaches broadband, miniaturization, high isolation and offers excellent diversity performance.

关键词： MIMO PIFA isolation capacitive feed capacitive load

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Residual energy based multi-relay selection and power allocation scheme in two-way relay network

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The Journal of China Universities of Posts and Telecommunications 2013年第4期20卷 39-45页

作者： DAI Cui-qin LI Fu-jia ZHANG zu-fan Chongqing Key Lab of Mobile Communication Technology Chongqing University of Posts and Telecommunications

In this paper, we have proposed a multi-relay selection and power allocation scheme for two-way relay network which aims to maximize the sum-rate of two-way relay system. First, to prolong network lifetime, a multi-relay selection strategy is proposed in which both channel state information （CSI） and remaining energy （RE） are considered. Next, a multi-relay power allocation algorithm based on convex optimization （MRPA-CO） is presented. To reduce the computational complexity, it can be divided into two steps： terminal nodes power allocation （TNPA） and relay nodes power allocation （RNPA）. Simulation results indicate that the proposed relay selection strategy can significantly prolong network lifetime compared to other relay selection strategies which consider CSI only, and the MRPA-CO algorithm has great advantage over equal power allocation （EPA） on sum-rate in two-way relay network.

关键词： two-way relay remaining energy multi-relay selection power allocation sum-rate

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Joint power allocation and subcarrier pairing in OFDM-based cooperative relaying system

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The Journal of China Universities of Posts and Telecommunications 2012年第1期19卷 24-30页

作者： DAI Cui-qin ZHAO Xiao-yu ZHANG zu-fan Chongqing Key Lab of Mobile Communication Technology Chongqing University of Posts and TelecommunicationsChongqing 400065China

This paper proposes rate-maximized （MR） joint subcarrier pairing （SP） and power allocation （PA）（MR-SP＆PA）, a novel scheme for maximizing the weighted sum rate of the orthogonal-frequency-division multiplexing （OFDM） relaying system with a decode-and-forward （DF） relay. MR-SP＆PA is based on the joint optimization of both SP and power allocation with total power constraint, and formulated as a mixed integer programming problem in the paper. The programming problem is then transformed to a convex optimization problem by using continuous relaxation, and solved in the Lagrangian dual domain. Simulation results show that MR-SP＆PA can maximize the weighted sum rate under total power constraint and outperform equal power allocation （EPA） and proportion power allocation （PCG）.

关键词： OFDM DF relaying power allocation SP MR-SP&PA

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