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Search Results: 1 - 10 of 334104 matches for " 王桂宝 "
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圆形极化阵列到达角和极化参数估计

- , 2016, DOI: 10.13190/j.jbupt.2016.02.014
Abstract: 摘要 为了放宽布阵条件,解决现有方法存在的相位模糊问题,采用旋转不变信号谱估计算法研究了基于均匀圆形极化阵列的信号参数估计.利用子空间理论,并根据导向矢量的特点得到相邻阵元间的相位差估计,消除了相位模糊;利用沿z轴方向放置的电偶极子阵列导向矢量和磁偶极子阵列导向矢量之间的关系,通过矩阵运算给出了信号极化和到达角估计的最小二乘解,该算法不需要搜索运算和参数配对运算,仿真实验结果验证了该算法的有效性.
In order to relax the embattle conditions and solve the phase ambiguity of existing algorithm, a signal parameter estimation algorithm based on the polarized uniform circular polarized array was studied using the estimating signal parameters via rotational invariance techniques (ESPRIT) algorithm. The phase differences between two adjacent array elements are obtained based on the performance of steering vector using the subspace theory, the phase ambiguity is resolved. Using the relationship of array manifold vector between z-axis electric dipoles and magnetic dipoles, the least squares solution to the signal polarization and direction of arrival estimations were given with matrix operations without spectral peak searching and parameter matching. Simulations verify the effectiveness of the algorithm.
由《农业机械学报》载文看我国农业机械的现状和研究方向
Current Situation and Research Directions for Agricultural Machinery from Publish Papers Analysis of Transactions of the Chinese Society for Agricultural Machinery
 [PDF]

徐瑞清, , 杨文丽,
Hans Journal of Agricultural Sciences (HJAS) , 2013, DOI: 10.12677/HJAS.2013.32009
Abstract: 本文通过对《农业机械学报》20121~9期载文进行分析,发现了我国农业机械的研究现状,对我国农机科研工作者的研究内容进行了分析。
In this paperthe authors discover the current research situation of Chinese agricultural machinery, and analyse the research content of Chinese agricultural machinery, base on the publish papers analysis of transactions of the Chinese society for agricultural machinery from No. 1-9 in2012.
Research of the Routing Techniques in Wireless Mobile Ad Hoc Networks
无线移动Ad Hoc网络的路由技术研究

,,
计算机系统应用 , 2005,
Abstract: 无线移动Ad Hoc网络(MANET)作为可移动分布式多跳无线网络,没有预先确定的网络拓扑或网络基础设施以及集中控制。为了在如此的网络中促进通信,路由技术主要用于在节点之间发现路径。Ad Hoc网络路由协议的主要目的是在网络拓扑的动态变化下任意两个节点之间建立一个使得通信总费用和带宽耗费最少的正确和有效的通信路径。在这篇论文中,论述了无线Ad Hoc网络的特性、问题和技术,并通过不同的标准对存在的一些路由协议进行分类和比较。
卫星遥感在煤炭工业中的应用实践与展望
卢中正,飞跃,
地球信息科学学报 , 2000,
Abstract: 本文简要介绍了卫星遥感在煤炭资源及煤炭伴生矿产资源调查、煤炭基地水资源调查、煤矿生产中地质灾害调查预报、煤层自燃监测和矿区环境调查监测等方面的应用实践及取得的主要成果。
电偶极子组天线幅相误差校正
,陶海红,兰美
北京邮电大学学报 , 2013, DOI: 10.13190/j.jbupt.2013.05.004
Abstract: 存在幅相误差时,基于特征值分解的子空间类算法性能急剧恶化。为了校正幅相误差,用一个线极化校正源信号,无须准确已知校正源的波达方向。在校正过程中只需将待校正电偶极子组绕x轴旋转90°,根据旋转前后到达角的关系以及对应电场分量的比值关系得到到达角的估计,进而得到幅相误差的估计,导出了到达角和幅相误差估计的闭式解。数值仿真结果证明了该方法的有效性。
光催化分解水制氢用CoO/CaTiO3催化剂——制备方法及光催化作用机理探讨
,延吉,秦娅,
化工学报 , 2005,
Abstract: 以钛酸四丁酯的水解产物TiO(OH)2和硝酸钙为原料,固态反应合成CaTiO3.研究了负载组分对CaTiO3光催化分解水制氢活性的影响,结果表明:CoO、NiO、Ag均对CaTiO3的活性有促进作用,其中CoO的作用最为明显.考察了负载钴后处理方法对CaTiO3活性的影响,并利用XRD、XPS、SEM等手段对负载催化剂进行了表征.研究显示:CaTiO3被Co(NO3)2溶液浸渍后,经加热分解,500℃氢气还原,再于200℃氧气氧化处理后,得到均匀分布于CaTiO3表面、金属钴表面覆盖CoO的负载结构,这种结构使催化剂表现出较高的活性.探讨了负载型催化剂CoO/CaTiO3的光催化作用机理.
低浓度 NaCl 对苋菜生长的影响
,姚冬琳,
北方园艺 , 2010, DOI: 10.11937/bfyy.201020022
Abstract:
设施农业科学与工程专业教材建设几个关键问题的调查与分析
Investigation and Analysis on Several Key Problems of Teaching Material Construction in Spacialty of Environment Controlled Agriculture Science and Engineering
 [PDF]

久兴,, 宋士清,, 宁永红, 杨靖
Vocational Education (VE) , 2015, DOI: 10.12677/VE.2015.42004
Abstract:
为明确设施农业科学与工程(本科)专业教材的在教学活动中的重要性,了解现行教材存在的主要问题,以便确定新教材编写的指导思想和体例,选择了关于设施农业科学与工程(本科)专业教材建设的几个关键问题,对本科院校教师、本科院校学生、中高职教师进行了问卷调查。结果表明:专业教材是影响教学质量的最重要因素。当前专业教材存在的主要问题是内容陈旧,理论性强,实践性弱。未来新教材适宜按照行动体系编写,依据工作任务划分结构,根据需要组织理论知识和专业技能等内容。在表现形式上,应增加对文字内容起辅助说明作用的照片、插图数量。这一调查结果可为国内高校设施农业科学与工程(本科)专业教材建设提供参考。
In order to make clear the importance of professional textbooks of environment controlled agri-culture science and engineering (undergraduate) spacialty in teaching activities, and understand the problem existing in the current textbooks, so as to determine the guiding ideology and style of writing, an investigation on several key problems of teaching material construction in spacialty of environment controlled agriculture science and engineering was carried out. Respondents included medium occupation school teachers, higher occupation school teachers, undergraduate college students, and university teachers. The investigation result indicated that, the professional teaching material is the most important factor to influence the teaching quality. The main problems existing in current textbooks are that the contents are relatively old; the theory is relatively strong; and the practice is relatively weak. The new textbook should be written according to the action system, in other words; the structure should be divided according to the task; the theoretical knowledge and professional skills should be inserted according to the need. In the form of performance, photos and illustrations which play a supporting role should be added to the content. This result could provide reference for teaching material construction of environment controlled agriculture science and engineering (undergraduate) spacialty.
SL-益生素对小白鼠体重及其单核吞噬细胞功能的影响
,,,田浩
微生物学报 , 1995,
Abstract: 研究了SL-益生素(SL-P)对小白鼠体重和单核吞噬细胞功能的影响。经急性毒性实验检查,该益生素无急性毒性,无急性致病作用。灌服SL-P10d后,小鼠体重较对照组有明显提高。经过SL-P处理后,小鼠腹腔巨噬细胞(PMφ)的吞噬率和吞噬指数较对照组有显著提高。灌服SL-P10d后,小鼠单核吞噬细胞的水解酶类:血清溶菌酶(血清LSZ),腹腔巨噬细胞溶菌酶(PMφLSZ),腹腔巨噬细胞酸性磷酸酶(PMφACP)的活性均有不同程度的提高,并呈现一定的剂量依赖关系,表明SL-P对小鼠单核吞噬细胞的吞噬和杀菌功能有明显的促进作用。
自协作原理对马氏体表象理论计算的改进
,谷南驹,
自然科学进展 , 2003,
Abstract: 以Fe-31Ni为例,根据相变过程中变体之间以孪晶关系进行自协作,从而得到不畸变不转动惯习面这一原理,从马氏体相变时的位移矢量入手,计算了马氏体转变时呈孪晶关系的两个自协作变体的体积分数、惯习面指数及相变后马氏体与奥氏体之间的取向关系.由于在计算总畸变矩阵时不用考虑任何附加的转动矩阵,并应用了镜面对称操作,使计算过程简单,结果准确.
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