特征结构提取的高阶Hopfield神经网络实现

本文首先建立了特征结构提取问题的罚函数表示，通过对罚函数求极小可以求得原始协方差矩阵的主特征向量及其对应的特征值。为了求得其他特征结构，特构造了一个协方差矩阵序列。如果将罚函数展开并进行整理，高阶Ｈｏｐｆｉｅｌｄ神经网络可被引入到特征结构提取中。这种方法比较直观，它将网络稳定时的输出与所求协方差矩阵的主特征向量的各个分量相对应，而网络稳定时的能量则对应于协方差矩阵的迹与所求特征值之差，计算机仿真结果验证了这种方法的正确性。     

炭黑／结晶性含氟树脂合金在自控温加热电缆中应用

选择了结晶性含氟树脂添加改性剂为树脂基体，与炭黑制居复合导电体系。通过这个对体系不同条件下ＰＴＣ特性的研究，对其配方与加工工艺进行优化。并利用扫描电镜，Ｘ射线衍射，ＤＳＣ等分析测试手段，对体系的各种开矿结构进行了研究，阐明了该导电复合体系的形态结构与性能的关系。     

灰铸铁的应力屈服曲面及其三维热弹塑性应力解析

对原有的灰铸铁件应力屈服曲面进行了合理的简化,使其在理论上合理,工程应用上更为方便。建立了灰铸铁件三维非稳态热弹塑性应力场的有限元方法。以灰铸铁哑铃件为对象,用新屈服曲面对其应力发展过程进行了模拟,且比较了用新旧屈服面计算得到的结果。     

Choroidal and iris angioarchitecture of the newt: A scanning electron-microscopic study of vascular corrosion casts

The corrosion cast technique provided for the first time an excellent three-dimensional visualization of the vascular pattern of the choroid and iris in the newt eye. The results show the presence of a single arterial afference to the choroidal and iris capillaries: the ophthalmic artery is the origin fo both ciliary arteries and the long posterior ciliary artery. Slightly behind the equatorial circumference of the eyeball the venous drainage consists of a single vessel on the dorsal side and two distinct vessels on the ventral one. It receives blood from both iris and choroid. The surface of the plastic endocasts shows some details of fine luminal structures of the endothelial cells. Shallow depressions may be regarded as imprints of endothelial cell nuclei, and they are distinctly different for arteries and capillaries. The angioarchitecture of the newt eye differs from that of brain in that hairpin-shaped capillary loops are not observed at all.     

非线性系统两变量控制下的分枝特性

采用分枝理论推导非线性系统两变量P和PI控制下的分枝特性,所导得的几个定理阐明了简单分枝点和Hopf分枝点的位置和性质。一个简化精馏塔模型用于演示这一过程,展示出精馏塔系统在闭环时,可能出现多态和极限环。     

Phenological studies of selected savanna mosses of south-western Nigeria

It was established that there is little diversity of bryophytes in the derived savanna. Mosses were found in the sampling sites, whereas liverworts were rarely observed. The reproductive methods of four dominant sexually reproducing savanna mosses —Archidium ohioense, Bryum coronatum, Fissidens minutifolius andTrachycarpidium tisserantii were monitored over two consecutive rainy seasons. Protonemal and gametophyte production were noticed in the field in March/April, and capsule dehiscence and spore dispersal occurred in September/October. The sequential stages of development, starting with gametangial production and ending with the falling of the dehisced capsules, occurred within the rainy season. However,A. ohioense andT. tisserantii did not discharge their spores easily (cleistocarpous), unlike the stegocarpous speciesB. coronatum andF. minutifolius. Water availability and possibly high humidity may have contributed to growth. The short period between sex organ formation and dehiscence of capsule seen in these studies, compared with the longer period in some temperate mosses, may be an advantage for bryophytes in a savanna environment.     

提高大型仪器设备利用率的新途径

大型仪器设备是高校开展教学、科研的物质保证,是高校实验室的主要技术装备,衡量一所高校办学实力和水平的重要指标之一.……     

企业文化定位的影响因素分析

通过讨论企业性质、企业能动要素价值的变迁以及企业的素质和外部环境状况对企业文化定位的影响,认为不同的企业都有其独特的个性,因而企业文化必须根据企业的素质和外部环境的状况以及所处的生命周期阶段来定位,确立其实际的内容.     

分次环的Brown-McCoy根

研究了分次环的Brown-McCoy根,用新的方法证明并推广了文献[1]中的主要结果,证明在比自由群更广泛的群类上分次环的Brown-McCoy根是分次的.