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Penetration characteristics of VLF wave from atmosphere into lower ionosphere

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Earthquake Science 2010年第3期23卷 275-281页

作者： Shufan Zhao Xuhui Shen Weiyan Pan xuemin zhang Li Liao Institute of Earthquake Science China Earthquake Administration Beijing 100036 China Qingdao Branch China Research Institute of Radiowave Propagation Qingdao 266107 China Institute of Geophysics China Earthquake Administration Beijing 100081 China

The factors affecting the reflection and transmission coefficient of the ionosphere have been *** factors include wave frequency,incident angle,geomagnetic inclination,electron density and collision frequency in the *** ionosphere refractive index is also *** ionosphere above 70 km is considered to be homogeneous and anisotropic,and the reflection and transmission coefficient matrix is calculated using matrix *** the Booker quartic equation is solved to get the refractive index in the *** results show that when the wave frequency is higher,it is easier to penetrate into the ionosphere from its bottom boundary and the propagation attenuation in the ionosphere is ***（traverse electric） wave and TM（traverse magnetic） wave can both penetrate into the ionosphere with a small incident angle,while TE wave can hardly transmit into the ionosphere when the incident angle is *** transmission coefficient decreases as the geomagnetic inclination *** and TM wave cannot penetrate into the ionosphere at magnetic *** the electron collision frequency is higher,it is easier for VLF wave to penetrate into the ionosphere and the attenuation of ordinary wave is weaker,which may be caused by the energy transportation between the waves and the *** ordinary（O） wave experiences severer attenuation than extraordinary（X） wave,and X wave is a penetration mode whereas O wave is a non-penetration mode in the *** the results indicate that VLF wave with higher frequency is easier to penetrate into the ionosphere and to be recorded by the satellites at high *** is hard for ULF and the lower frequency VLF wave to transmit into the ionosphere directly for the severe reflection and *** may transmit into the ionosphere with a small incident angle due to the nonlinear effect,for example,the interaction between the waves and the particles or cross modulation,and then propagate

关键词： VLF wave low ionosphere reflection coefficient transmission coefficient refractive index

Genome-wide identification of WRKY gene family and expression analysis under abiotic stresses in Andrographis paniculata

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BIOCELL 2021年第4期45卷 1107-1119页

作者： QICHAO WANG WUJING ZENG BASHARAT ALI xuemin zhang LING XU ZONGSUO LIANG Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation College of Life Sciences and MedicineZhejiang Sci-Tech UniversityHangzhou310018China Department of Agronomy University of AgricultureFaisalabad38040Pakistan Tianjin Tasly Modern TCM Resources Co. Ltd.Tianjin300410China

Andrographis paniculata(***)is a Chinese herbal medicine that clears away heat,reduces inflammation,protects the liver,and promotes *** WRKYs of *** are still not well characterized,although many WRKYs have been identified in various plant *** the present study,59 *** WRKY(ApWRKY)genes were identified and renamed on the basis of their respective chromosome *** ApWRKYs were divided into three groups via phylogenetic analysis according to their WRKY domains and combined with WRKY of *** 59 identified ApWRKY transcription factors were nonuniformity distributed on 23 chromosomes of *** the structural analysis of the conserved motifs,different ApWRKYs structures showed different biological functions,and the ApWRKY transcription factor had certain species-specificity in the evolutionary *** expression patterns of the 41 ApWRKYs were examined through quantitative real-time PCR(qRT-PCR)in various tissues and under abiotic stresses(salt).The results showed that most of the ApWRKY had different reactions to salt *** addition,the content of the four main secondary metabolites in *** leaves was determined under salt *** results show that under a low concentration of salt treatment,the synthesis of andrographolide can be improved.

关键词： A.paniculata ApWRKY Secondary metabolites Diterpene lactones Andrographolide Abiotic stress

肺磨玻璃结节确诊早期浸润性腺癌的危险因素及预测模型构建

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现代肿瘤医学 2024年第6期32卷 1070-1074页

作者：宋晏张高潮张学敏陈正福付伟汉中三二〇一医院核医学科陕西汉中723000

目的:探讨肺磨玻璃结节(ground glass nodules,GGN)确诊早期浸润性腺癌危险因素并构建预测模型,旨在为浸润性肺腺癌早期鉴别诊断及治疗方案制定提供更多参考。方法:回顾性分析2017年01月至2023年01月于我院诊治肺GGN患者共171例194个结... 详细信息

目的:探讨肺磨玻璃结节(ground glass nodules,GGN)确诊早期浸润性腺癌危险因素并构建预测模型,旨在为浸润性肺腺癌早期鉴别诊断及治疗方案制定提供更多参考。方法:回顾性分析2017年01月至2023年01月于我院诊治肺GGN患者共171例194个结节临床资料,根据术后病理组织学检查是否为浸润性肺腺癌分为浸润组(158个)和非浸润组(36个);比较两组临床病理及影像学特征资料;采用单因素和多因素法评估肺GGN确诊早期浸润性腺癌独立危险因素,肺GGN确诊早期浸润性腺癌风险预测模型构建及效能分析。结果:171例194个结节经术后病理组织学检查确诊为浸润性肺腺癌结节共158个,占比为81.44%。两组合并胸膜凹陷征比例、结节实性成分比例、SUV指数比较差异有统计学意义(P0.05)。多因素分析结果显示,合并胸膜凹陷征、结节实性成分比例及SUV指数均是肺GGN确诊早期浸润性腺癌独立危险因素(P<0.05)。利用回归模型的独立影响因素以及P值预测概率对患者肺GGN确诊早期浸润性腺癌风险进行预测,约登指数分别为52.55%、94.13%、70.72%、96.66%。结论:肺GGN患者是否属于浸润性腺癌与是否合并胸膜凹陷征、结节实性成分比例及SUV指数关系密切;而基于上述指标构建预测模型能够准确指导浸润性肺腺癌早期鉴别诊断。

关键词：磨玻璃结节肺腺癌浸润性癌 PET/CT 模型

西兰花选择性采收作业平台识别切割装置设计与试验

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农业工程学报 2024年第1期40卷 68-79页

作者：宋昊张学敏谢鹏飞陈相安刘思瑶中国农业大学工学院北京100083 现代农业装备优化设计北京市重点实验室北京100083

针对当前人工采收西兰花存在季节性劳动力需求强、劳动强度大以及成本高等问题,该研究基于西兰花的农艺特性与形态特征设计了一种西兰花选择性采收作业平台,旨在能够实现对西兰花的自主识别切割作业。首先,该平台采用“识别-采收”一体... 详细信息

针对当前人工采收西兰花存在季节性劳动力需求强、劳动强度大以及成本高等问题,该研究基于西兰花的农艺特性与形态特征设计了一种西兰花选择性采收作业平台,旨在能够实现对西兰花的自主识别切割作业。首先,该平台采用“识别-采收”一体化作业模式,通过对采收作业平台的关键部件进行设计与选型,建立了西兰花的视觉识别系统和定心切割机构。其次,根据西兰花茎秆与割刀之间的相互作用关系,采用对数螺线作为切割曲线设计了一种等滑切角割刀,确定了割刀滑切角40°、切割半径135 mm、割刀长度260 mm等关键切割参数。根据西兰花茎秆的材料属性参数,基于ANSYS Workbench/LS-DYNA软件对茎秆切割过程进行显式动力学仿真分析,以割刀刃角和转速为控制因子,以最大切割力为试验指标,利用正交试验优化设计,确定了茎秆切割过程的最优参数组合为割刀刃角20°、转速1 rad/s,在此参数下最大切割力为725.82 N,切割质量较优。最后,对采收作业平台进行性能试验,结果表明视觉系统能够有效识别自然环境下的成熟西兰花植株,检测效果良好;定心切割机构可快速平稳的切入并切断西兰花茎秆,切断表面平整光滑;采收作业平台整体漏收率在10%以下、检测准确率为90%、切茎合格率为88.9%,可满足西兰花选择性采收的作业需求。该研究可为西兰花选择性采收作业装备的设计开发提供理论参考和实际借鉴。

关键词：收获农业机械机器视觉西兰花切割装置显式动力学

Multi-level multi-area hybrid automatic voltage control system and its trial operation in Northeast China Grid

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Science China(Technological Sciences) 2011年第9期54卷 2501-2505页

作者： zhang xuemin MEI ShengWei SU XinYi WANG Gang JIA Wei SHAO GuangHui XU XingWei State Key Lab of Power Systems Dept. of Electrical Engineering Tsinghua University Beijing 100084 China Northeast China Grid Company Limited Shenyang 110181 China

In order to coordinate automatic voltage control （AVC） systems of a large interconnected system, a multi-level multi-area hybrid automatic voltage control （MLMA-HAVC） system was constructed. This system began its trial operation in the Northeast China Grid in January 2010, and for the first time in China and abroad it realized automatic close-loop control of multi-area and multi-level interconnected power grid and multi-objective self-approaching optimization in aspects of security, high quality and economic operation. This system has three breakthroughs in theory and engineering application： l） Established the MLMA-HAVC theory to solve multi-objective optimization of large-scale system; 2） proposed reactive power/voltage coordination control method to inhibit or further eliminate regional oscillations; 3） presented advanced state estimation algorithm to guarantee acquisition of high reliability data. This paper summarizes the basic principle of MLMA-HAVC, and reports engineering realization of MI ,MA-HAVC system in tha Northeast China Grid.

关键词： hybrid automatic voltage control coordinated control advanced state estimation

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百合花期调控研究进展

分子植物育种 2024年第12期22卷 3954-3960页

作者：康圣楠陈曦张雪敏张铭芳潘文强程兆伦杨凤萍吴健张秀海于晓南杜运鹏北京林业大学园林学院国家花卉工程技术研究中心观赏植物种质创新与分子育种北京市重点实验室城乡生态环境北京市实验室北京100083 北京市农林科学院北京市功能花卉工程技术研究中心北京100097 中国农业大学观赏园艺与园林学院北京市观赏作物开发与质量控制重点实验室北京100193 蒙阴县住房和城乡建设局山东276200

百合是世界著名花卉,具有较高的观赏价值及经济价值。开花时间是影响花卉观赏的重要性状,花期调控对生产和应用有着极其重要的意义。百合的花期调控分子研究主要涉及的调控途径有光周期途径,春化途径,赤霉素途径,年龄途径,自主途径。本... 详细信息

百合是世界著名花卉,具有较高的观赏价值及经济价值。开花时间是影响花卉观赏的重要性状,花期调控对生产和应用有着极其重要的意义。百合的花期调控分子研究主要涉及的调控途径有光周期途径,春化途径,赤霉素途径,年龄途径,自主途径。本研究概述了百合的花期调控分子机制的最新研究进展,以期对百合成花的分子调控机理研究提供参考。

关键词：百合开花时间基因调控途径光周期春化作用

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海上L区稀疏井网沉积微相刻画研究

石油化工应用 2024年第7期43卷 75-80页

作者：张学敏郝明慧杨发荣朱建英海洋油气勘探国家工程研究中心北京100028 中海油能源发展股份有限公司提高采收率重点实验室天津300452 中海油能源发展股份有限公司工程技术分公司天津300452

海上L区井网稀疏井数少、目标储层地震分辨率差、制约储层沉积微相刻画精度,为解决小层沉积微相刻画难的问题,建立了以沉积模式为指导、单井微相作约束、多地震属性综合对比的沉积微相刻画方法,完成稀疏井网小层沉积微相识别刻画研究,... 详细信息

海上L区井网稀疏井数少、目标储层地震分辨率差、制约储层沉积微相刻画精度,为解决小层沉积微相刻画难的问题,建立了以沉积模式为指导、单井微相作约束、多地震属性综合对比的沉积微相刻画方法,完成稀疏井网小层沉积微相识别刻画研究,明确工区微相展布特征,相演化模式验证结果可靠。形成的稀疏井网沉积微相刻画方法,为海上稀疏井网储层沉积微相刻画提供参考和借鉴意义。

关键词：海上L区稀疏井网沉积微相刻画研究

Preface to the special issue on electromagnetic phenomena related to seismic and volcanic activities from EMSEV in 2016

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Earthquake Science 2017年第4期30卷 165-166页

作者： xuemin zhang Katsumi Hattori Valerio Tramutoli Institute of Earthquake Forecasting China Earthquake AdministrationBeijing 100036China Graduate School of Science Chiba University1-33YayoiInageChiba 263-8522Japan Engineering School(SI) University of Bailicata-Via Dell'Ateneo Lucano10-85100 PotenzaItaly

EMSEV, Electromagnetic Studies of Earthquake and Volcanoes, set up in 2002, is a joint academic organization by multi-associations in IUGG （International Union of Geodesy and Geophysics）, including IAGA （International Association of Geomagnetism and Aeronomy）, IASPEI （International Association of Seismology and Physics of the Earth＇s Interior）, IAVCEI （International Association of Volcanology and Chemistry of the Earth＇s Interior）.

关键词： In Preface to the special issue on electromagnetic phenomena related to seismic and volcanic activities from EMSEV in 2016

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海上L区低渗储层分类评价及有利区优选

复杂油气藏 2024年第1期17卷 44-49页

作者：张学敏但玲玲魏莉许靖康朱建英中海油能源发展股份有限公司工程技术分公司天津300452 延边大学工学院吉林延吉133002

海上L区目标层属于海上特低渗储层,为准确进行储层分类评价、指导储层有利区的优选,在统计借鉴已有低渗储层分类评价成果基础上,结合目标区低渗储层特征,厘定低渗储层分类评价参数,采用综合分类系数法完成低渗储层分类评价及有利区优选... 详细信息

海上L区目标层属于海上特低渗储层,为准确进行储层分类评价、指导储层有利区的优选,在统计借鉴已有低渗储层分类评价成果基础上,结合目标区低渗储层特征,厘定低渗储层分类评价参数,采用综合分类系数法完成低渗储层分类评价及有利区优选。研究认为L区目标层主要发育Ⅲ类储层,其次是Ⅳ和Ⅴ类储层,Ⅰ、Ⅱ类储层不发育,Ⅲ类储层连片分布的区域为储层有利区。研究结果可以较好地指导储层开发有利区的优选。

关键词：低渗储层储层分类分类评价方法有利区优选