基于CWT自相似特性的飞机目标HRRP分类法

为了解决高分辨率距离像 (HRRP)分类的姿态敏感和距离像对齐问题 ,基于连续小波变换 (CWT)的自相似特性 ,构造了能量尺度分形维数。分别在 3个极化测量通道和两个尺度区间上 ,从 HRRP的 CWT能量随尺度的演化过程中提取了原始特征集。采用 Fisher可分性准则作判据 ,进一步确定了 3维最佳特征向量。并从理论和实验上证明了 ,能量尺度分形维数特征较不敏感于噪声和目标方位角的变化 ,同时不受目标径向位移和距离像平移的影响 ,是性能良好的飞机目标分类特征     

数字递推滤波器的分析与应用

通过对数字滤波器的分析与实验研究,提出了数字滤波器不仅能处理低频信号,而且还能够对高频信号实现滤波,并在实践中取得了较好的效果,这将有益于扩大计算机的应用领域。     

球磨中B_2型FeAl的嵌镶碎化和长程有序度

研究了Ｂ２型金属间化合物 ＦｅＡｌ在机械球磨过程中的嵌镶碎块尺寸与长程有序度之间的关系。发现随球磨时间的增长，嵌镶碎块尺寸和长程有序度同时减小。由于嵌镶碎化主要由位错亚晶粒造成，应用Ｃｏｔｔｒｅｌｌ气团模型可建立嵌镶碎块尺寸与长程有序度之间的关系式。所得的这个关系式表明，长程有序度的降低主要是由位错与点阵原子的相互作用引起的。     

关于点列上射影变换的一点注记

讨论点列上射影变换的Steiner定义与Von Staudt定义的差别。主要结论如下:这两个定义在实点列上是等价的。但在夏点列上并不等价;就有限域GF(p~n)上的点列而言,当素数p≠2,n=1时,这两个定义是等价的,当素数p≠2,自然数n≠1时,这两个定义并不等价。     

对影响铅球投掷远度因素的探讨

本文用抛体运动规律,对影响铅球投掷远度的诸因素,采用改变因素对投掷远度变化率的分析,指出影响铅球投掷远度的主要因素是出手速度。其次是出手高度,第三是出手角度,进一步阐述了如何提高出手速度采用最佳出手角度和适宜的出手高度的方法。     

nm级制造用三维微定位的扫描探针显微镜

介绍一种用于ｎｍ级制造具有ｘｙｚ三维微定位能力的扫描探针显微镜（ＳＰＭ）．采用电磁足周期性地夹紧与松开，结合压电陶管的轴向伸缩变形的微位移爬行器构成三维微定位机构．扫描范围可达２０μｍ×２０μｍ，且探针可在样品表面ｘ和ｙ方向上１０ｍｍ×１０ｍｍ范围内实行ｎｍ级的定位．探针在ｚ方向接近样品表面也可自动进行．给出了微定位器的运动分辨率、速度与工作频率，以及在扫描道显微（ＳＴＭ）方法下测得的高定向石墨表面原子图像     

浅论按数量标志分组时的组数和组距

阐述了统计分组法的意义,探讨了对总体按数量标志分组时确定组数应遵循的四项原则,即质别原则;特征原则;大量原则;便利原则。并结合集合与区间的概念对组距进行了新的解释,给出了计算组距的新公式。     

纵向岭谷三江并流区河谷地貌特征分析

西南纵向岭谷地貌区北部的三江并流区是我国高山深谷发育的典型区域。金沙江、怒江、澜沧江、独龙江自北向南奔流，形成了较为典型的以峡谷为主的河谷地貌。其河谷地貌的主要特征有：突出的纵向岭谷地貌，构成了少有的三江并流奇观；地貌相对高差大，河谷深切；河谷地貌形成演化发育明显受地质构造控制；流域范围内地貌类型和地貌组合多样化特征突出；地质地貌环境具有较强烈的生态脆弱性；河谷支流水源多发源于高山湖泊，两岸支流河谷分布不均衡。形成了独具特色的“三江并流”河谷地貌。     

Phylogenetic relationships of native and introduced Bemisia tabaci (Homoptera:Aleyrodidae) from China and India based on mtCOI DNA sequencing and host plant comparisons

Phylogenetic relationships for Bemisia tabaci were reconstructed by analysis of a ～780 bp fragment of the mitochondrial cytochrome oxidase I (mtCOI) gene with an emphasis on geographic range and distribution among eight eudicot plant families that are common hosts of B. tabaci worldwide to elucidate key phylogeographic linkages between populations extant in China (n=31) and India (n=34). Bootstrap values for the Maximum Parsimony tree were highly robust for all major nodes involving the major Asian clade, subgroups, and sister groups within, at 92%—100%. Between-clade distances for the Southeast Asia and three other major clades, e.g. from sub-Sahara Africa, North Africa-Mediterranean, and the Americas, were approximately >16% divergent. Two major Asian subgroups (I, II) were resolved, which represented populations indigenous to the region, comprising two (I a, I b) and five (II a—e) sister groups, respectively, which diverged by 11%. Two distinct populations from sunflower in Hyderabad grouped separately within the two Asian subgroups. All other populations grouped uniquely within Asian subgroup II or I. The “B” biotype was identified in 23 collections from China at 97.3%—99.5% nucleotide identity with “B” biotype reference sequences; it was not identified in collections from India. The majority of haplotypes were associated with 3—4 plant families, with one exception that for sister group IId (sesame, India), it might be monophagous. Thus, B. tabaci from the southeastern and near eastern regions of the Asian continent comprise of a large number of ancestral, richly divergent, mostly polyphagous populations. This region is therefore hypothesized to constitute an important Old World center of diversification for the B. tabaci complex, together with sub-Saharan Africa.