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三维雷暴云电耦合数值模式中空间电位的求解

高原气象 2008年第3期27卷 648-656页

作者：郭凤霞张义军言穆弘中国科学院寒区旱区环境与工程研究所西部气候环境与灾害实验室甘肃兰州730000 中国气象科学研究院雷电物理与防护工程实验室北京100081

将电路分析方法引入三维雷暴云动力—电耦合数值模式中,考虑了带电水成物粒子对电导率的影响,直接用模式计算求解与雷暴云中流动的带电粒子有关的电流密度。比较分析了雷暴云内首次放电出现之前电路分析法和泊松方程得到的电位和电场。... 详细信息

将电路分析方法引入三维雷暴云动力—电耦合数值模式中,考虑了带电水成物粒子对电导率的影响,直接用模式计算求解与雷暴云中流动的带电粒子有关的电流密度。比较分析了雷暴云内首次放电出现之前电路分析法和泊松方程得到的电位和电场。结果表明,雷暴云内电导率普遍大于晴天大气,峰值位于各极性电荷区中心。与雷暴云中流动的带电粒子有关的电流密度的正、负最大值分别对应正、负电荷区中心,当电荷密度的绝对值不超过0.7nC.m-3时,其最大值的量级为10-9A.m-2,传导电流和位移电流最大值的量级均为10-8A.m-2,都为负,均在中部负电荷区中心。电路分析法得到的电位的垂直廓线与电荷结构的相互关系更明显,垂直电场的正、负最大值分别处于电荷密度最大的中部负电荷中心的上边缘和下边缘,与以往的观测结果更接近。

关键词：雷暴云数值模拟电导率空间电位空间电场

闪电产生氮氧化物(LNO_X)及其输送过程的模式计算

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高原气象 2006年第2期25卷 229-235页

作者：郭凤霞言穆弘张义军中国科学院寒区旱区环境与工程研究所甘肃兰州730000

利用三维强风暴动力电耦合模式,模拟分析了一次雷暴过程中放电活动特征及平流和湍流对LNOX的输送特征。结果表明,在中部负电荷区域的上边缘,对应上升气流区外围、水平流场中心部位的区域,因为放电传输距离较长,所以强放电区主要落在这... 详细信息

利用三维强风暴动力电耦合模式,模拟分析了一次雷暴过程中放电活动特征及平流和湍流对LNOX的输送特征。结果表明,在中部负电荷区域的上边缘,对应上升气流区外围、水平流场中心部位的区域,因为放电传输距离较长,所以强放电区主要落在这些部位,且向上传输。在负电荷中心区也有少数放电点,但传输距离较短。闪电产生的氮氧化物逸出闪道后,被云中平流和湍流输送,最后在弱流场区域内形成LNOX浓度中心,峰值达9×10-9。LNOX的输送主要以平流为主,但在云底层及雷暴消散阶段,湍流输送也起重要作用。在雷暴云消亡期,LNOX的峰值为2.7×10-9,比晴天值大1个量级。

关键词：数值模式放电 LNOx 时空分布输送

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暴雨内涝下城市路网抗涝韧性评估

交通运输系统工程与信息 2024年第5期24卷 226-236页

作者：金溪穆延武汉理工大学土木工程与建筑学院武汉430070

极端降雨给城市路网的正常运行带来了极大挑战,为了评估在应对极端降雨时路网的抗涝韧性,本文采用场景模拟方法分析暴雨内涝灾害对路网的影响;以道路水深是否超过水深阈值为标准,判断道路的连通性,构建以节点强度和不同水深下道路速度... 详细信息

极端降雨给城市路网的正常运行带来了极大挑战,为了评估在应对极端降雨时路网的抗涝韧性,本文采用场景模拟方法分析暴雨内涝灾害对路网的影响;以道路水深是否超过水深阈值为标准,判断道路的连通性,构建以节点强度和不同水深下道路速度的衰减函数为计算指标的综合评价框架;基于降雨—积水过程下道路系统的性能变化曲线和4R特征理论,分析4种暴雨重现期下路网的抗涝韧性;提出通过改造易涝交通枢纽提高路网抗涝韧性的提升策略。结果表明:降雨对路网服务性能的影响要大于对路网结构性能的影响,路网的抗涝韧性随着降雨重现期的增大而减小,道路的淹没程度与道路等级和降雨强度两个方面有关;易涝交通枢纽对路网抗涝韧性有较大影响,降雨重现期越小,影响越大。在实施提升策略后,可以显著提升路网的鲁棒性和快速性,增强路网的抗涝韧性。

关键词：城市交通抗涝韧性洪涝模拟道路网络城市内涝

Navigating Epstein–Barr virus autoimmunity:role of NK cells and T cells in multiple sclerosis

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Signal Transduction and Targeted Therapy 2024年第3期9卷 833-835页

作者： Chu Xie Cong Sun mu-Sheng Zeng State Key Laboratory of Oncology in South China Guangdong Provincial Clinical Research Center for CancerGuangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and TherapySun Yat-sen University Cancer CenterGuangzhouP.R.China

In a recent study published in Cell,Vietzen and colleagues discovered the novel role of natural killer(NK)cells and EBVspecific CD8+T cell response in controlling EBV-inducing autoimmune response and collectively def... 详细信息

关键词： Epstein sclerosis killer

Minimalistic approach to left atrial appendage occlusion guided by cardiac computed tomography angiography

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Journal of Geriatric Cardiology 2024年第4期21卷 431-442页

作者： Xian-Sai MENG Qing-Song WANG Xin-yan WANG Xu LU yang mu Jing WANG Ting-Ting SONG Yun-Dai CHEN Tao CHEN Jun GUO Graduate School of Chinese PLA Medical College BeijingChina Senior Department of Cardiology the Sixth Med-ical CenterChinese PLA General HospitalBeijingChina

OBJECTIVE To assess the feasibility and safety of the minimalistic approach to left atrial appendage occlusion(LAAO) guided by cardiac computed tomography angiography(CCTA).METHODS Ninety consecutive patients who underwent LAAO, with or without CCTA-guided, were matched(1:2). Each step of the LAAO procedure in the computed tomography(CT) guidance group(CT group) was directed by preprocedural CT planning. In the control group, LAAO was performed using the standard method. All patients were followed up for 12 months, and device surveillance was conducted using *** A total of 90 patients were included in the analysis, with 30 patients in the CT group and 60 matched patients in the control group. All patients were successfully implanted with Watchman devices. The mean ages for the CT group and the control group were 70.0 ± 9.4 years and 68.4 ± 11.9 years(P = 0.52), respectively. The procedure duration(45.6 ± 10.7 min vs. 58.8 ± 13.0 min,P < 0.001) and hospital stay(7.5 ± 2.4 day vs. 9.6 ± 2.8 day, P = 0.001) in the CT group was significantly shorter compared to the control group. However, the total radiation dose was higher in the CT group compared to the control group(904.9 ± 348.0 m Gy vs.711.9 ± 211.2 m Gy, P = 0.002). There were no significant differences in periprocedural pericardial effusion(3.3% vs. 6.3%, P = 0.8) between the two groups. The rate of postprocedural adverse events(13.3% vs. 18.3%, P = 0.55) were comparable between both groups at 12 months *** CCTA is capable of detailed LAAO procedure planning. Minimalistic LAAO with preprocedural CCTA planning was feasible and safe, with shortened procedure time and acceptable increased radiation and contras consumption. For patients with contraindications to general anesthesia and/or transesophageal echocardiography, this promising method may be an alternative to conventional LAAO.

关键词： anesthesia matched approach

Existence of Positive Solutions to a Fractional-Kirchhoff System

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 225-240页

作者： Peng-fei Li Jun-hui Xie Dan mu School of Mathematics and Statistics Hubei Minzu UniversityEnshi445000China

LetΩbe a bounded smooth domain in RN(N≥3).Assuming that 00 are constants,we consider the existence results for positive solutions of a class of fractional elliptic system below,{(a+b[u]^(2)_(s))(-Δ)^(s)u=vp+h_(1)(x,u,v,▽u,▽v),x∈Ω,(-Δ)^(s)v=u^(q)+h_(2)(x,u,▽,▽u,▽v),x∈Q,u,v>0,x∈Ω,u=v=0,x∈RN\Ω.Under some assumptions of hi(x,u,v,▽u,▽v)(i=1,2),we get a priori bounds of the positive solutions to the problem(1.1)by the blow-up methods and rescaling *** on these estimates and degree theory,we establish the existence of positive solutions to problem(1.1).

关键词： fractional-Kirchhoff system a priori bounds degree theory positive solution

Hybrid electromechanical properties of hetero-doped and homogeneously bonded dual-mode pressure sensor for indoor body area network node

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Science China(Information Sciences) 2024年第1期67卷 240-253页

作者： Junbin YU Shuai XIAN Jinbiao mu Min WANG Yin WANG Xiaojuan HOU Le ZHANG Jian HE Jiliang mu Xiujian CHOU Science and Technology on Electronic Test and Measurement Laboratory North University of China Sichuan Aerospace Fenghuo Servo Control Technology Corporation

Pressure sensors are considerably important for continuous monitoring of human movement and the surrounding environment to construct a caregiving system for the elderly living *** challenge for pressure sensors that still remains is combining self-driven,comfort,and ***,an all-in-one conformal pressure sensor(ACPS) based on a homogeneous integrated triboelectric-piezoelectric hybrid sensor is *** ACPS has dual-mode sensing properties due to coupling triboelectrification and piezoelectric effect ensuring a stable response to various external ***-coated glass microspheres and polyacrylonitrile were uniformly filleted into the silicone rubber substrate using a hetero-doping method to create a stretchable electrode layer with flexible conformal characteristics and a piezoelectric layer with excellent piezoelectric properties,***,the triboelectric layer was fabricated using the same silicone rubber,allowing ACPS to be homogeneously bonded into an all-in-one structure with reliable *** allowed various functional layers to have outstanding interface characteristics and thus improve the electrical transmission *** developed ACPS had outstanding sensitivity(1.04 V/104Pa),high linearity(about 0.984),a wide measurement range(10–700 k Pa),and can accurately and continuously distinguish multiple ***,using a homemade signal processing circuit,ACPSs can be deployed in the human body and the room as indoor body area network *** successfully applied to the remote tracking of daily dynamic home life and the remote operation of small electrical equipment,these ACPSs can achieve real-time caregiving for the elderly living *** an application area desperately needed by society,this study envisions a caregiving system for the elderly living alone without violating personal privacy.

关键词： dual-mode pressure sensor homogeneous bonding all-in-onestructure indoor body area network node elderly caregiving microsystem

Spatial correlations in time and frequency domains between chlorophyll-a concentration and environmental factors in the Bohai Sea

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Journal of Oceanology and Limnology 2024年第4期42卷 1143-1156页

作者： Wan XU Di mu Zhenteng yanG Dekui YUAN Department of Mechanics Tianjin UniversityTianjin 300350China Engineering Research Center of Seawater Utilization of Ministry of Education School of Chemical Engineering and TechnologyHebei University of TechnologyTianjin 300130China State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

Based on the reconstructed MODIS data and ECMWF reanalysis data from 2003 to 2021,spatial correlations between chlorophyll a(Chl a)and sea surface temperature(SST),photosynthetically available radiation(PAR),aerosol optical thickness(AOT),and wind speed(WS)in the Bohai Sea were analyzed from the perspective of time domain and frequency *** indicate that the frequency domain analysis was more conducive to revealing the correlations between Chl a and environmental *** spatial pattern of time-domain correlations was similar to the isobaths of the Bohai Sea,which was positive in shallow waters and negative in deep waters for SST,PAR,and AOT,and was reversed for ***-domain correlations were obtained by performing Fourier Transform and were higher than correlations in time *** spatial distributions indicated that the effects of SST and PAR on Chl a were greater than AOT and WS in the Bohai ***,cross-spectrum analysis was applied to explore the response relationships.A depth-dependent pattern was shown in correlations and time lags,indicating that the influential mechanism of environmental factors on Chl-a concentration is related to seawater depth.

关键词： chlorophyll a(Chl a) frequency domain spatial correlation Bohai Sea

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播撒金属丝对雷暴云电结构影响模拟研究

高原气象 2000年第1期19卷 32-42页

作者：孙安平言穆弘张鸿发张义军中国科学院寒区旱区环境与工程研究所甘肃省兰州市730000

利用积云动力—起电二维轴对称模式 ,模拟分析了雷暴不同发展阶段在云中上升气流速度最大区播撒金属丝对雷暴云电结构的总体影响。通过与未播撒模拟结果相比较 ,发现各种降水粒子的荷电率及电场强度都有所减小 ,这种减小在雷暴发展的成... 详细信息

利用积云动力—起电二维轴对称模式 ,模拟分析了雷暴不同发展阶段在云中上升气流速度最大区播撒金属丝对雷暴云电结构的总体影响。通过与未播撒模拟结果相比较 ,发现各种降水粒子的荷电率及电场强度都有所减小 ,这种减小在雷暴发展的成熟阶段尤为明显 ,雷暴云内的扩散、电导和感应起电机制作用减弱。通过不同播撒位置和播撒率的敏感性试验得到 ,在云中强上升气流区播撒对垂直电场的抑制效果比在云底和云顶更好 ,不同的播撒率引起的电场强度减小幅度不同 ,播撒率存在一阈值。

关键词：雷暴云电结构金属丝影响模拟雷暴