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A comparative study on 3-D solar wind structure observed by Ulysses and MHD simulation

Science Bulletin 2005年第7期50卷 672-678页

作者： FENG Xueshang, XIANG Changqing, ZHONG Dingkun & FAN Quanlin SIGMA Weather Group, key Laboratory of Space Weather key Labo- ratory of Geospace Environment and Geodesy, Ministry of Education, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080, China SIGMA Weather Group Key Laboratory of Space Weather Beijing China key Labo-ratory of Geospace Environment and Geodesy Ministry of Education Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China

During Ulysses’ first rapid pole-to-pole transit from September 1994 to june 1995, its observations showed that middle- or high-speed solar winds covered all latitudes except those between ?20° and +20° near the ecliptic plane, where the velocity was 300―450 km/s. At poleward 40°, however, only fast solar winds at the speed of 700―870 km/s were observed. In addition, the transitions from low-speed wind to high-speed wind or vice versa were abrupt. In this paper, the large-scale structure of solar wind observed by Ulysses near solar minimum is simulated by using the three-dimensional numerical MHD model. The model com- bines TVD Lax-Friedrich scheme and MacCormack II scheme and decomposes the calculation region into two re- gions: one from 1 to 22 Rs and the other from 18 Rs to 1 AU. Based on the observations of the solar photospheric magnetic field and an addition of the volumetric heating to MHD equations, the large-scale solar wind structure mentioned above is reproduced by using the three-dimensional MHD model and the numerical results are roughly consistent with Ulysses’ observations. Our simulation shows that the initial magnetic field topology and the addition of volume heating may govern the bimodal structure of solar wind observed by Ulysses and also demonstrates that the three-dimensional MHD numerical model used here is efficient in modeling the large-scale solar wind structure.

关键词： Ulysses observation solar wind structure numerical simulation.

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Seasonal patterns of spatial differentiation of landcover change in China

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Chinese Science Bulletin 1999年第4期44卷 362-364页

作者： CHEN YufengState key Laboratory of Resource and Environment Information System , Institute of Geography, Chinese Academy of Sciences, Beijing 100101, China State key Laboratory of Resource and Environment Information System Institute of Geography Chinese Academy of Sciences Beijing China

Using the 1°×1° NOAA AVHRR NDVI data set in China, an index on the spatial different gradient of landcover is created. Then based on the index and supported by the geographical information system, it is revealed through principal component and factor analyses methods that there exist four types of seasonal patterns of spatial differentiation of landcover change in China, i.e. November to next March type, june to September type, May or October type and April type.

关键词： landcover spatial differentiation seasonal pattern.

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高校图书馆基于学科映射的数据资源增值服务

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大学图书馆学报 2023年第3期41卷 19-27,18页

作者：张俊娥陈建龙北京大学图书馆北京100871

介绍了对图书馆文献分类与高校学科体系映射关系的研究及其应用服务实践,提出了以高校各学科的“培养目标、专业范围和知识体系/课程”的文本内容为基础,析出其所涉及的主题词,利用图书馆按主题分类的编目专业优势,由专业编目人员通过... 详细信息

介绍了对图书馆文献分类与高校学科体系映射关系的研究及其应用服务实践,提出了以高校各学科的“培养目标、专业范围和知识体系/课程”的文本内容为基础,析出其所涉及的主题词,利用图书馆按主题分类的编目专业优势,由专业编目人员通过主题词分配《中国图书馆分类法》分类号,把高校学科体系与《中国图书馆分类法》体系关联起来,进而建立了分层分级的分类文献资源与高校学科的映射关系模型,并提出了高校图书馆基于学科映射更好地服务于学科专业建设的数据服务路线。

关键词：文献分类学科专业学科映射数据增值服务高校图书馆

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A Detection Method of WLAN Security Mechanisms Based on MAC Frame Resolution

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Wuhan University Journal of Natural Sciences 2017年第2期22卷 93-102页

作者： LI june YUAN Kai ZHOU Liang HAN Lifang LI Ling WANG Zhihao LIU Yinbin HUANG Wenbin key Laboratory of Aerospace Information Security and Trusted Computing of Ministry of Education Wuhan 430072HubeiChina School of Computer Wuhan UniversityWuhan 430072HubeiChina School of Electrical Engineering Wuhan UniversityWuhan 430072HubeiChina China Electric Power Research Institute Beijing 100192China

Security mechanism detection is not only an important content of vulnerabilities evaluation but also the foundation of key strength test for wireless local area network （WLAN）. This paper analyzes the specifications of WLAN security mechanisms and points out the defects in design of security mechanisms detection algorithm based on the standards. By capturing and analyzing a large number of Beacon frames from different vendor＇s access points （APs）, we summarize the relevant fields and information elements in a Beacon frame, and present their values or status when an AP is set to every specific security mechanism. A detection algorithm of WLAN security mechanisms is proposed based on the experimental study result and the pseudo code of a reference implementation for the algorithm is designed. The validity of the algorithm is illustrated by examples, which shows it can detect every WLAN security mechanism accurately.

关键词： IEEE 802.11 security mechanism detection algorithm MAC frame resolution vulnerabilities evaluation

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Partial Oxidation of Methane to Formaldehyde over Superfine Mo/ZrO2 Catalysts

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Journal of Energy Chemistry 2002年第Z1期 15-17页

作者： Xin Zhang,Dehua He,Qijian Zhang,Qing Ye,Qiming ZhuState key Laboratory of C1 Chemistry and Technology, Department of Chemistry, Tsinghua University, Beijing 100084, China[Manuscript received May 22, 2002 revised june 15, 2002]

Superfine Mo/ZrOcatalysts were prepared for partial oxidation of methane to HCHO and characterized by BET, XRD, LRS, H2-TPR and XPS. Mo existed mainly in the form of Zr（MoO4）2, and the catalytic performance and phys... 详细信息

关键词： methane partial oxidation formaldehyde Mo/ZrO2 catalysts Zr(MoO4)2

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基于模糊测试的GOOSE协议解析漏洞挖掘方法

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中国电力 2022年第4期55卷 33-43页

作者：刘林彬苗泉强李俊娥空天信息安全与可信计算教育部重点实验室(武汉大学国家网络安全学院) 湖北武汉430072 光电对抗测试评估技术重点实验室河南洛阳471000

现有工控协议模糊测试方法未考虑嵌入式终端系统特点,且对未采用传输控制协议/网际协议(TCP/IP)的工控协议研究较少。基于模糊测试提出一种通用面向对象变电站事件(GOOSE)协议解析漏洞挖掘方法。使用变异方式构造测试用例,给出基于GOOS... 详细信息

现有工控协议模糊测试方法未考虑嵌入式终端系统特点,且对未采用传输控制协议/网际协议(TCP/IP)的工控协议研究较少。基于模糊测试提出一种通用面向对象变电站事件(GOOSE)协议解析漏洞挖掘方法。使用变异方式构造测试用例,给出基于GOOSE报文字段类型、抽象语法标记1(ASN.1)编码方式和比特翻转的3类变异策略;提出基于心跳报文和系统运行信息的终端异常监测方法。设计所提方法的实施系统架构和测试流程,在智能变电站实验室环境中,对某厂家嵌入式终端进行测试,发现2个未公开的GOOSE协议解析漏洞,验证所提方法的有效性,提出防范基于此类漏洞的畸形报文攻击的建议。

关键词：模糊测试 GOOSE协议电网嵌入式终端漏洞挖掘畸形报文攻击

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纳米Si/C/N复相粉体的微波介电特性

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物理学报 2001年第12期50卷 2471-2476页

作者：赵东林周万城万伟西北工业大学凝固技术国家重点实验室

研究了纳米Si C N复相粉体在 8.2— 18GHz的微波介电特性 ,采用双反应室激光气相合成纳米粉体装置 ,以六甲基二硅胺烷 ((Me3Si) 2 NH) (Me∶CH3)为原料 ,用激光诱导气相反应法合成纳米Si C N复相粉体 ,复相粉体的粒径为 2 0— 30nm .纳... 详细信息

研究了纳米Si C N复相粉体在 8.2— 18GHz的微波介电特性 ,采用双反应室激光气相合成纳米粉体装置 ,以六甲基二硅胺烷 ((Me3Si) 2 NH) (Me∶CH3)为原料 ,用激光诱导气相反应法合成纳米Si C N复相粉体 ,复相粉体的粒径为 2 0— 30nm .纳米Si C N复相粉体与石蜡复合体的介电常量的实部 (ε′)和虚部 (ε″)以及介电损耗角正切 (tanδ =ε″ ε′)随纳米粉体含量的增加而增大 ,ε′和ε″与纳米粉体体积分数 (v)之间符合二次函数关系 (ε′ ,ε″ =Av2 +Bv +C) ,纳米Si C N复相粉体的ε′和ε″在 8.2— 18GHz随频率的增大而逐渐减小 .纳米Si C N复相粉体中的SiC微晶固溶了大量的N原子 ,在纳米Si C N复相粉体中形成大量的带电缺陷 ,在电磁场作用下形成极化耗散电流 ,极化弛豫是损耗电磁波的主要原因 ,纳米Si C N复相粉体的介电损耗较大。

关键词：纳米Si/C/N复相粉体微波介电常量微观结构纳米材料硅碳氮复相粉体微波介电特性

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Study on Bifunctionality of Mo/HZSM-5 Catalysts for Methane Dehydro-Aromatization under Non-oxidative Condition

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Journal of Energy Chemistry 2002年第Z1期 18-27页

作者： Lingling Su,Yide Xu,Xinhe BaoState key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, P. O. Box 110, Dalian, 116023, China[Manuscript received june 10, 2002 revised July 20, 2002]

The optimum Mo/[H] ratio per unit cell of the active precursors in Mo/HZSM-5 catalysts for methane dehydro-aromatization, measured by 1H MAS NMR, was found to be about 1 when adjusting the acid sites by altering either the SiO2/Al2O3 ratios or the Mo loading. This implies that a concerted interaction between the Mo species and the Bronsted acid sites probably features the bifunctionality of the Mo/HZSM-5 catalyst. On the other hand, it was found that the driving force for Mo species to move into the HSZM-5 zeolite channels and the interaction between the Mo species and the Bronsted acid sites are closely and proportionably related with the amount of Bronsted acid sites per unit cell.

关键词： methane dehydro-aromatization Mo/HZSM-5 SiO2/Al2O3 ratio bifunctionality

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Overseas immigration of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), invading Korea and Japan in 2019

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Insect Science 2022年第2期29卷 505-520页

作者： Ming-Fei Wu Guo-Jun Qi Hui Chen Jian Ma Jie Liu Yu-Ying Jiang Gwan-Seok lee Akira Otuka Gao Hu College of Plant Protection Nanjing Agricultural UniversityNanjing210095 China Guangdong Provincial key Laboratory of High Technology for Plant Protection/Plant Protection Research Institute Guangdong Academy of Agricultural SciencesGuangzhou510640 China Division of Pest Forecasting China National Agro-Tech Extension and Service CenterBeijing100026 China Department of Agro-food Safety and Crop Protection National Institute of Agricultural SciencesWanju55365 Korea Institute of Agricultural Machinery National Agriculture and Food Research OrganizationTsukuba3058517 Japan

The fall armyworm(FAW),Spodoptera frugiperda(***),spread rapidly in Africa and Asia recently,causing huge economic losses in crop *** armyworm caterpillars were first detected in South Korea and Japan in june ***,the migration timing and path for FAW into the countries were estimated by a trajectory simulation approach implementing the insect's flight *** result showed that FAWs found in both South Korea and Japan were estimated to have come from eastern China by crossing the Yellow Sea or the East China Sea in 10–36 h in three series of *** the first series,FAW moths that arrived on Jeju Island during 22–24 May were estimated to be from Zhejiang,Anhui and Fujian Provinces after 1–2 nights’*** the second series,it was estimated that FAW moths landed in southern Korea and Kyushu region of Japan simultaneously or successively during 5–9 june,and these moths mostly came from Guangdong and Fujian *** FAW moths in the third series were estimated to have immigrated from Taiwan Province onto Okinawa Islands during 19–24 *** these migrations,southwesterly low-level jets extending from eastern China to southern Korea and/or Japan were observed in the northwestern periphery of the western Pacific Subtropical *** results,for the first time,suggested that the overseas FAW immigrants invading Korea and Japan came from eastern and southern *** study is helpful for future monitoring,early warning and the source control of this pest in the two countries.

关键词： Asian migration arena atmospheric circulation Spodoptera frugiperda trajectory analysis windbome insect migration

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从技术中心主义到人本主义:智慧城市研究进展与展望

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地理科学进展 2022年第3期41卷 488-498页

作者：郭杰王珺姜璐张虹鸥黄耿志广东省科学院广州地理研究所/广东省遥感与地理信息系统应用重点实验室广州510070 柏林自由大学中国研究中心德国柏林10115 香港城市大学公共政策学院中国香港999077 中山大学地理科学与规划学院广州510275 南方海洋科学与工程广东省实验室(珠海) 广东珠海519082

随着5G网络、物联网、云计算、大数据分析、地理信息系统等新技术的兴起,探索更具包容性和创新潜力的参与式治理,引导高效的技术研发与运用,实现城市“以地方现实为基础、以社会需求为导向”的智慧化转型,已成为国内外城市地理学的重要... 详细信息

随着5G网络、物联网、云计算、大数据分析、地理信息系统等新技术的兴起,探索更具包容性和创新潜力的参与式治理,引导高效的技术研发与运用,实现城市“以地方现实为基础、以社会需求为导向”的智慧化转型,已成为国内外城市地理学的重要与前沿议题。人本主义视角下的智慧城市研究,为地理学者介入这一领域提供了理论工具。不同于技术中心主义将智慧城市视作由数字技术构成的物理空间集合,人本主义强调特定情境下的技术、社会(人文治理)与空间的互动。该视角呼吁对多方行动者参与技术研发、基础设施建设与治理决策的合作互动开展微观研究,以揭示智慧城市的共建过程与地方性驱动机制。论文梳理了国内外人本主义研究的最新进展,认为该视角下的研究仍然沿袭“技术中心”或采用与之对立的“知识中心”立场,而缺少技术—社会互动的视角来理解城市智慧化转型。论文提出未来值得深入探讨的议题,即技术与社会(治理)的共生性、围绕技术研发的社会关系互动复杂性、技术研发与关系互动的语境化分析。探讨以上议题有助于理解智慧城市如何作为一个复杂地域系统,在人与技术的持续互动中发生转型,也可为未来中国相关研究提供理论借鉴。

关键词：智慧城市城市治理技术中心主义人本主义技术—社会协同

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