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JEM-1400透射电子显微镜在纳米材料测试中的应用
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作者 韩沐昕 李冬梅 赵晟锌 《中国现代教育装备》 2024年第3期26-28,32,共4页
以JEM-1400透射电子显微镜为例,介绍了透射电镜的基本结构、工作方式、电子光学成像原理及分辨率、放大倍率等基本概念,探讨了影响纳米材料样品高质量成像的因素及对策。从灯丝高度及束流强度调试方面讨论了提高材料样品分辨率的可行性... 以JEM-1400透射电子显微镜为例,介绍了透射电镜的基本结构、工作方式、电子光学成像原理及分辨率、放大倍率等基本概念,探讨了影响纳米材料样品高质量成像的因素及对策。从灯丝高度及束流强度调试方面讨论了提高材料样品分辨率的可行性:基于灯丝像,通过调节灯丝饱和度和偏压,使灯丝发射量达到15μA;在保证灯丝寿命的前提下,分辨率从过去的200 nm提高到10 nm以下。 展开更多
关键词 透射电子显微镜 jem-1400 纳米材料 灯丝饱和度 灯丝发射量
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JEM-2100透射电镜像散调整经验总结
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作者 陈大兴 《分析仪器》 CAS 2024年第1期72-75,共4页
JEM-2100透射电镜拍摄清晰的照片需要对像散认真调整,像散是由光束经透镜折射后,光束不能聚焦于一点而形成的。由于像散是难以消除的,只能尽量减少,而且像散调节需要按照一定的步骤和要求进行,本文对像散调节的基本方法和要求进行了总结。
关键词 jem-2100透射电镜 像散调节
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Numerical modeling of deep-seated landslides interacting with man-made structures 被引量:3
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作者 Giovanni Barla 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2018年第6期1020-1036,共17页
This paper describes the interaction between deep-seated landslides and man-made structures such as dams, penstocks, viaducts, and tunnels. Selected case studies are reported first with the intent to gain insights int... This paper describes the interaction between deep-seated landslides and man-made structures such as dams, penstocks, viaducts, and tunnels. Selected case studies are reported first with the intent to gain insights into the complexities associated with the interaction of these structures with deep-seated landslides(generally referred to as deep-seated gravity slope deformations, DSGSDs). The main features, which characterize these landslides, are mentioned together with the interaction problems encountered in each case. Given the main objective of this paper, the numerical modeling methods adopted are outlined as means for increase in the understanding of the interaction problems being investigated. With the above in mind, the attention moves to an important and unique case history dealing with the interaction of a large-size twin-tunnel excavated with an earth pressure balance(EPB)tunnel boring machine(TBM) and a deep-seated landslide, which was reactivated due to the stress changes induced by tunnel excavation in landslide shear zone. The geological and geotechnical conditions are described together with the available monitoring data on the landslide movements, based on the advanced and conventional monitoring tools used. Numerical modeling is illustrated as an aid to back-analyze the monitored surface and subsurface deformations and to assist in finding the appropriate engineering solution for putting the tunnel into service and as a follow-up means for future understanding and control of the interaction problems. The simulation is based on a novel time-dependent model representing the landslide behavior. 展开更多
关键词 Deep-seated landslides man-made structures Landslide-structure interaction Monitoring of landslide movement Numerical modeling
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Considering and comparing regeneration in natural and man-made stands in northern Iran
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作者 Mir Mozaffar FALLAHCHAI 《Forestry Studies in China》 CAS 2012年第2期131-136,共6页
In this study the regeneration diversity of Syahkal forests afforestated and natural stands in north of Iran was studied and compared from the point of view of evenness and diversity index. In order to accomplish this... In this study the regeneration diversity of Syahkal forests afforestated and natural stands in north of Iran was studied and compared from the point of view of evenness and diversity index. In order to accomplish this study two natural and man-made stands that almost are located in the same height above the sea level were chosen. The area of each stand was 30 ha and the inventory was done by the random-systematic method with a 5R land measurement (500 m2) selected. Also, in order to study the regeneration in the center of each sample piece 125 square meters micro plots were formed. The results show that regeneration diversity index in natural stands is more than that in man-made stands which in this case Mc-Arthur index with 2.41 has the most amount while Simpson index with 0.543 has the least amount. But the evenness indexes in man-made stands are more than that in natural stand which the main reason is the purity of the man-made stand. 展开更多
关键词 diversity EVENNESS man-made stands Iran's forests
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Ecology and Fish Biodiversity of Man-Made Lakes of Southern Benin (West Africa): Implications for Species Conservation and Fisheries Management
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作者 Houehanou M. A. G. Gbaguidi Alphonse Adite Edmond Sossoukpe 《Journal of Environmental Protection》 2016年第6期874-894,共21页
Man-made lakes are alternative and potential habitats for biodiversity conservation, fisheries and extensive aquaculture. We investigated the ecology and the fish community structure of two (2) sand-dragged man-made l... Man-made lakes are alternative and potential habitats for biodiversity conservation, fisheries and extensive aquaculture. We investigated the ecology and the fish community structure of two (2) sand-dragged man-made lakes, Lake Ahozon and Lake Bewacodji of Southern Benin, with implications for species conservation, fisheries management and aquaculture valorization. From August 2014 to July 2015, habitats conditions were evaluated and fishes were sampled monthly with seine, cast net, experimental gill net and hooks in the open water and aquatic vegetation habitats of both lakes. Overall, the water quality of Lake Ahozon was globally favorable for the growth and the survival of the fish resources whereas Lake Bewacodji exhibited a poor water quality indicated mainly by an acid pH (mean: 6.32 ± 0.58) and low dissolved oxygen concentrations (mean: 3.52 ± 1.25 mg/l) caused by dense floating plants, Nymphea sp mainly and huge daily dumping of domestic wastes. The study revealed low species richness, d = 5.89 and d = 3.87, and low species diversity, H’ = 0.76 and H’ = 0.48 for Lakes Ahozon and Bewacodji, respectively, with Lake Ahozon more diverse than Lake Bewacodji. The fish community of Lake Ahozon comprised six (6) species, 3 cichlids Sarotherodon galilaeus, Oreochromis niloticus and Tilapia guineensis, the silver catfish, Chrysichthys nigrodigitatus (Claroteidae), the African bonytongue, Heterotis niloticus (Osteoglossidae), and the African catfish, Clarias gariepinus (Clariidae). Numerically, S. galilaeus dominated Lake Ahozon and made 85.21% of the sample. In Lake Bewacodji, the fish composition comprised four (4) species, Sarotherodon galilaeus multifasciatus, the dominant species making numerically 91.58% of the total sample, T. guineensis, C. gariepinus and C. nigrodigitatus. With regard to trophic structure, the fish assemblages of both lakes were numerically dominated by planktinovores/ detritivores, mainly S. galilaeus, O. niloticus, T. guineensis and C. nigrodigitatus making together 99.46% of Lake Ahozon fish community, and S. galilaeus multifasciatus, T. guineensis and C. nigrodigitatus accounting together for about 98.59% of Lake Bewacodji. In Lake Ahozon, standard length (SL) frequencies histograms showed an unimodal size distribution for H. niloticus, the nile tilapia O. niloticus and C. gariepinus whereas the two cichlids, S. galilaeus and T. guineensis exhibited a bimodal size distribution. In Lake Bewacodji, S. galilaeus multifasciatus, C. nigrodigitatus and C. gariepinus exhibited an unimodal size distribution. A sustainable exploitation of both man-made lakes requires the implementation of an integrated management scheme which should include habitat restoration and protection plan, fisheries/aquacultural valorization, ecological sound agriculture/ecotourism and environmental monitoring.   展开更多
关键词 Conservation Diversity Domestic Wastes FISHERIES Habitat Degradation MANAGEMENT man-made Lakes Sand-Dragging Sarotherodon galilaeus
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The 25th CIMFC(Bengbu 2019):Exploring the future of the man-made fibers
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《China Textile》 2019年第10期38-43,共6页
The 25th China International Man-made Fiber Conference (Bengbu 2019)(hereinafter referred to as CIMFC 2019), themed on “Opening and Integaration for Interactive Development — Coordinated Progress of Global Man-Made ... The 25th China International Man-made Fiber Conference (Bengbu 2019)(hereinafter referred to as CIMFC 2019), themed on “Opening and Integaration for Interactive Development — Coordinated Progress of Global Man-Made Fiber Industry”, was convened in Bengbu City, Anhui Province. CIMFC 2019 was sponcored by China National Textile and Apparel Council (CNTAC), organized by China Chemical Fibers Association, Chi-na Textile International Exchange Center, and China BBCA Group Corp., supported by Bengbu Municipal People’s Goverment, and co-organized by Bengbu Investment Promotion and Foreign cooperation Center, Bengbu Municipal Bureau of Commerce and Foreign Affairs, and Oerlikon Man-made Fiber. 展开更多
关键词 CIMFC Bengbu man-made fibers
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MAN-MADE
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作者 崔东豪(台湾)(绘画) 《世界儿童(漫画版)》 2010年第2期8-11,共4页
前情提要 似水与流年根据博士日记上面的提示一路找到太阳遗迹,终于见到了博士,博士向两人说明了一切,原来,流年竟是人造人……
关键词 初等教育 漫画 课外阅读 man-made
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MAN-MADE
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《世界儿童(漫画版)》 2010年第9期8-11,共4页
名月背叛了虎帝大人,他要所有的新型M-M战士听命于他。于是,被博士利用变身药丸救出的流年他们决定要阻止名月。
关键词 初等教育 漫画 课外阅读 man-made
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Man-made fiber industry enjoys optimistic transformation and upgrading
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《China Textile》 2017年第12期18-19,共2页
As an important fundamental industry of the national economy,the man-made fiber industrial chain is integrated into the era development and it assumes the responsibility of advancing.Each link of the industrial chain ... As an important fundamental industry of the national economy,the man-made fiber industrial chain is integrated into the era development and it assumes the responsibility of advancing.Each link of the industrial chain is connected with each other.After the development and accumulation of several decades,the new produced polyester,PTA and other plants keep 展开更多
关键词 man-made fiber industry enjoys optimistic transformation and upgrading PTA
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THE CAS AND CHINA'S FIRST MAN-MADE EARTH SATELLITE Lu Shouguan(Chinese Academy of Sciences)
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作者 Lu Shouguan Chinese Academy of Sciences Director of the former Task Office for Satellite Develop-ment under the CAS and former director of the CAS Bureau of Planning 《Bulletin of the Chinese Academy of Sciences》 2000年第1期52-62,共11页
In the festivedays whencelebrating the50th anniversa-ry of the found-ing of the Peo-ple’s Republic,and the 50th an-niversary of thefounding of theChinese Acad-emy of Scienc-es (CAS), it isnatural for thepeople to thi... In the festivedays whencelebrating the50th anniversa-ry of the found-ing of the Peo-ple’s Republic,and the 50th an-niversary of thefounding of theChinese Acad-emy of Scienc-es (CAS), it isnatural for thepeople to thinkwith pride ofChina’s 展开更多
关键词 Chinese Academy of Sciences THE CAS AND CHINA’S FIRST man-made EARTH SATELLITE Lu Shouguan CAS
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Notable effects on comprehensive techniques of man-made biosphere in rice fields
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作者 Feng Yilen,CNRRI 《Chinese Rice Research Newsletter》 1996年第4期12-12,共1页
Studied by Mr. LIU Zhongzhu, ex Chairman of Fujian Academy of Agri Sciences, a combined technique of man—made biosphere in rice fields deserves notice. The research indicated that using man—made biosphere in rice fi... Studied by Mr. LIU Zhongzhu, ex Chairman of Fujian Academy of Agri Sciences, a combined technique of man—made biosphere in rice fields deserves notice. The research indicated that using man—made biosphere in rice fields can enrich soil, reduce the infects of diseases, insects and weeds, economize the use of pesticide and herbicide, decrease green house effect, and improve atmosphere. As tested, the yield for rice is usually 10500—12000 kg/ha, for fish is usually 2250—3250 kg/ha. Again, about 50%—60% fertilizer and 30%—50% pesticide can be saved. The net income increased $ 1,080—1,800 per ha. 展开更多
关键词 Notable effects on comprehensive techniques of man-made biosphere in rice fields
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常规雷达JEM特征分析与目标分类的研究 被引量:13
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作者 丁建江 张贤达 《电子与信息学报》 EI CSCD 北大核心 2003年第7期956-962,共7页
该文研究了常规雷达回波中喷气发动机调制(JEM)特征产生机理、提取方法及用于目标分类的效能,先从理论上分析了常规雷达飞机回波中JEM特征的产生机理,并比较了直升机、螺旋桨飞机和涡扇喷气机回波中JEM周期特征的差别。再讨论了实际回... 该文研究了常规雷达回波中喷气发动机调制(JEM)特征产生机理、提取方法及用于目标分类的效能,先从理论上分析了常规雷达飞机回波中JEM特征的产生机理,并比较了直升机、螺旋桨飞机和涡扇喷气机回波中JEM周期特征的差别。再讨论了实际回波中时域、频域、时频域方法分析和提取JEM周期特征的优劣,最后用AR双谱切片技术提取的JEM周期特征进行了目标分类和辨识实验,结果表明;JEM周期特征用于常规防空雷达飞机的分类是有效的,但又是有限的。 展开更多
关键词 雷达 jem 目标分类 喷气发动机调制 提取方法 目标识别
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基于JEM效应的一种雷达目标识别方法
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作者 张善文 甄蜀春 赵兴录 《电光与控制》 北大核心 2000年第4期1-4,共4页
根据JEM(喷气发动机调制)效应和雷达目标回波谱经特点,本文提出了一种雷达目标识别方法。此方法是利用小波变换,得到雷达目标回波信号的频率调频指数,对信号进行相位补偿,然后滤掉信号中的机身频谱和多普勒频谱,再进行相位补... 根据JEM(喷气发动机调制)效应和雷达目标回波谱经特点,本文提出了一种雷达目标识别方法。此方法是利用小波变换,得到雷达目标回波信号的频率调频指数,对信号进行相位补偿,然后滤掉信号中的机身频谱和多普勒频谱,再进行相位补偿,用FFT(快速傅立叶变换)就可以得到目标的调制谱,由此实现目标识别。由实测数据进行分机处理,证明利用目标的调制谱识别目标,认识效果很好。 展开更多
关键词 喷气发动机调制效应 防空雷达目标识别 jem效应
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Impacts of artificial dams on terrestrial water storage changes and the Earth's elastic load response during 1950-2016: A case study of medium and large reservoirs in Chinese mainland
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作者 Linsong Wang Mingtao Zhu +2 位作者 Yulong Zhong Jianwei Sun Zhenran Peng 《Geodesy and Geodynamics》 EI CSCD 2024年第3期252-263,共12页
The construction of dams for intercepting and storing water has altered surface water distributions, landsea water exchanges, and the load response of the solid Earth. The lack of accurate estimation of reservoir prop... The construction of dams for intercepting and storing water has altered surface water distributions, landsea water exchanges, and the load response of the solid Earth. The lack of accurate estimation of reservoir properties through the land surface and hydrological models can lead to water storage simulation and extraction errors. This impact is particularly evident in many artificial reservoirs in China. The study aims to comprehensively assess the spatiotemporal distribution and trends of water storage in medium and large reservoirs(MLRs) in Chinese mainland during 1950-2016, and to investigate the gravity,displacement, and strain effects induced by the reservoir mass concentration using the load elasticity theory. In addition, the impoundment contributions of MLRs to the relative sea level changes were assessed using a sea-level equation. The results show impoundment increases in the MLRs during1950-2016, particularly in the Yangtze River(Changjiang) and southern basins, causing significant elastic load effects in the surrounding areas of the reservoirs and increasing the relative sea level in China's offshore. However, long-term groundwater estimation trends are overestimated and underestimated in the Yangtze River and southwestern basins, respectively, due to the neglect of the MLRs impacts or the uncertainty of the hydrological model's output(e.g., soil moisture, etc.). The construction of MLRs may reduce the water mass input from land to the ocean, thus slowing global sea level rise. The results of the impact of human activities on the regional water cycle provide important references and data support for improving the integration of hydrological models, evaluating Earth's viscoelastic responses under longterm reservoir storage, enhancing in-situ and satellite geodetic measurements, and identifying the main factors driving sea level changes. 展开更多
关键词 man-made dams Terrestrial water storage Elastic load response Sea level changes Chinese mainland
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JEMS软件在《材料现代研究方法》实践教学中的应用
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作者 侯小虎 赵学平 +2 位作者 刘飞 白朴存 张静 《内蒙古工业大学学报(自然科学版)》 2022年第5期424-428,共5页
《材料现代研究方法》作为理论教学与实践教学相结合的课程,在材料科学与工程课程中占有重要的位置。其中透射电子显微学部分学习难度较大,应用到科研实践时往往教学和实践有一定差距。为了解决该问题,将JEMS软件应用到《材料现代研究... 《材料现代研究方法》作为理论教学与实践教学相结合的课程,在材料科学与工程课程中占有重要的位置。其中透射电子显微学部分学习难度较大,应用到科研实践时往往教学和实践有一定差距。为了解决该问题,将JEMS软件应用到《材料现代研究方法》教学中,利用该软件对7000系铝合金中η′(MgZn_(2))相进行了选区电子衍射模拟和高分辨像模拟。结果表明:JEMS软件可以将《材料现代研究方法》教学中难点进行可视化处理,让学生更容易理解透射电子显微学,为以后科研工作打下基础。 展开更多
关键词 《材料现代研究方法》 jemS软件 选区电子衍射 高分辨像
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基于时频图像处理的JEM分类识别方法 被引量:4
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作者 雷志勇 黄忠平 +2 位作者 汪文英 吴刚 张良 《中国电子科学研究院学报》 北大核心 2021年第1期39-45,共7页
机载雷达探测飞机目标时,可通过提取JEM特征进行直升飞机、螺旋桨飞机、喷气式飞机分类识别,虽然其理论基础已相对成熟,但在机载杂波背景下对低SNR调制信号的检测与分类识别有待进一步提升,以改进工程化过程中分类识别的稳健性。文中在... 机载雷达探测飞机目标时,可通过提取JEM特征进行直升飞机、螺旋桨飞机、喷气式飞机分类识别,虽然其理论基础已相对成熟,但在机载杂波背景下对低SNR调制信号的检测与分类识别有待进一步提升,以改进工程化过程中分类识别的稳健性。文中在回顾JEM理论分析的基础上,分析了观测角度、叶片螺距、转子交调、RCS闪烁、雷达工作波形等因素对JEM回波的影响,提出了基于超分辨时频图像的融合检测方法,综合预处理、时频分析、时频图像融合检测、JEM特征判决等策略,解决杂波背景下低SNR调制回波的检测与识别难题,并用机载雷达实测民航飞机的回波数据进行了验证,具备较高的工程应用价值。 展开更多
关键词 机载雷达 jem特征 分类识别 时频图像 超分辨处理
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JEM—100CXⅡ电子显微镜全自动真空系统及其故障排除
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作者 杨文庆 《中国医学物理学杂志》 CSCD 1991年第Z1期55-55,共1页
电子显微镜真空系统的作用是使镜筒内获得高真空。如镜筒内真空度差,则象的反差降低、电子束发射不稳定、灯丝寿命缩短,而且残余气体会污染样品。JEM—100CXⅡ电镜用二级扩散泵串联,镜筒内真空度优于3×10<sup>-5</sup>... 电子显微镜真空系统的作用是使镜筒内获得高真空。如镜筒内真空度差,则象的反差降低、电子束发射不稳定、灯丝寿命缩短,而且残余气体会污染样品。JEM—100CXⅡ电镜用二级扩散泵串联,镜筒内真空度优于3×10<sup>-5</sup>托(实际可以1×10<sup>-6</sup>托)。本文拟对该电镜全自动真空系统:一、真空检测:用皮喇尼规和集成开关元件作控制电路, 展开更多
关键词 真空系统 真空度降低 jem 开关元件 镜筒 故障排除 控制电路 残余气体 高真空 程序开关
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基于JEM的雷达窄带目标识别方法研究
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作者 刘婧逸 张靖 姚诚 《信息化研究》 2018年第3期18-21,共4页
文章针对实测数据进行基于喷气发动机调制(JEM)的雷达窄带目标识别技术研究。在提取JEM特征的基础上,从目标回波中提取目标运动特征、归一化方差、主旁瓣比、环境熵等特征进行特征融合,提出一种采用支持向量机(SVM)算法的基于JEM的多特... 文章针对实测数据进行基于喷气发动机调制(JEM)的雷达窄带目标识别技术研究。在提取JEM特征的基础上,从目标回波中提取目标运动特征、归一化方差、主旁瓣比、环境熵等特征进行特征融合,提出一种采用支持向量机(SVM)算法的基于JEM的多特征融合雷达窄带目标分类技术。仿真计算结果显示,使用该算法对实测窄带雷达回波数据进行分类,可以很好地对民航和直升机、无人机与汽车进行分类识别。 展开更多
关键词 窄带目标识别 喷气发动机调制 SVM 特征融合
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浅析JEOLJEM-2100F场发射透射电子显微镜的使用
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作者 滕颖丽 《现代科学仪器》 2015年第6期140-143,共4页
JEOLJEM-21OOF场发射透射电子显微镜是由日本电子株式会社制造的大型精密仪器。随着计算机技术和微电子技术的应用,使其控制变得简单,自动化程度大大提高,整体性能得到进一步提升。该仪器的主要特点是亮度高,柬斑小,分辨率高,新... JEOLJEM-21OOF场发射透射电子显微镜是由日本电子株式会社制造的大型精密仪器。随着计算机技术和微电子技术的应用,使其控制变得简单,自动化程度大大提高,整体性能得到进一步提升。该仪器的主要特点是亮度高,柬斑小,分辨率高,新式侧插测角台更容易倾转、旋转等等。JEM-21OOF场发射透射电子显微镜广泛应用于材料科学、生命科学、医学等领域,以及半导体、纳米材料等行业。本文介绍JEOLJEM-21OOF场发射透射电子显微镜的使用方法,通过系统分析,对透射电镜的维护保养工作提出了一些建议。 展开更多
关键词 jem-21 OOF场发射透射电镜 使用 维护
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多普勒频谱及JEM效应在空中目标识别中的应用分析 被引量:5
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作者 刘志成 何佳洲 《指挥控制与仿真》 2009年第1期38-41,45,共5页
为了获取进行空中目标识别的有效特征量,分析了多普勒频谱结构识别、调制谱识别和JEM周期特征识别等方法。采用将相位和幅度综合的方法,获得了更接近理论值的JEM周期平均值特征量,仿真结果说明综合特征量具有较小的估计标准差。最后,指... 为了获取进行空中目标识别的有效特征量,分析了多普勒频谱结构识别、调制谱识别和JEM周期特征识别等方法。采用将相位和幅度综合的方法,获得了更接近理论值的JEM周期平均值特征量,仿真结果说明综合特征量具有较小的估计标准差。最后,指出了该领域可能的研究方向。 展开更多
关键词 目标综合识别 多普勒频谱结构 jem效应
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