基于小波分解系数的贝叶斯人脸识别方法

本文给出了贝叶斯人脸识别方法中匹配准则的多个近似表达式及一种实用的快速计算方法,在此基础上,利用反对称双正交小波变换的微分算子功能,提出了一种利用两幅人脸图像的小波变换系数差作为模式矢量的贝叶斯人脸识别方法,并利用AR人脸图象库进行了实验,实验结果表明本文方法与基于图像灰度的类似方法相比,识别率提高8％左右,此外本文方法也提供了一条在图像压缩数据域中实现人脸识别的可能途径。     

强激光辐照下柱壳温度场的数值模拟

 用有限元方法数值模拟强激光辐照下柱壳上温度场的变化和分布情况，并对热性能参数随温度变化对温度场造成的影响进行了研究。     

第一讲中子散射与散裂中子源

中子散射是研究物质微观结构和动态的理想工具之一,广泛地应用于凝聚态物质研究和应用的众多学科领域.散裂中子源能是新一代的加速器基脉冲中子源,能为中子散射提供高通量的脉冲中子.文章简明地介绍了中子散射的特点和它作为物质结构和动态探针的优越性,以及散裂中子源的基本原理、发展状况和多学科的应用优势.我国计划建设的散裂中子源CSNS中,靶站将由多片钨靶、铍/铁反射体和铁/重混凝土生物屏蔽体组成.质子束功率100kW下,脉冲中子通量约为2.4×1016n/cm2/s.第一期将设计建造高通量粉末衍射仪、高分辨粉末衍射仪、小角散射仪、多功能反射仪和直接几何非弹性散射仪等五台典型的中子散射谱仪,以覆盖大部分的中子散射研究领域.     

新型电感储能脉冲功率驱动源

提出了将传统单个储能电感利用传输线分隔成两部分的新型电感储能脉冲功率驱动源技术方案。理论分析表明,利用传输线电容的耦合延时作用,可有效对调制器输出脉冲波形进行整形,并且可以进一步提高能量转换效率,从而克服传统电感储能脉冲功率源输出波形质量差(类三角波波形)的缺点。基于该思想开展了实验研究,获得了电压约300 kV,电流约20 kA的电子束,并成功驱动S波段磁绝缘线振荡器获得了百MW量级的微波输出。     

A Compact Magnetically Insulated Line Oscillator with New-Type Beam Dump

We present a compact improved model of the magnetically insulated line oscillator with new-type beam dump and other novel features. In the experiments, high-power microwave of the TM01 mode is generated from the device with a frequency range of 1.73-1.78 GHz and a peak power level of above 2 GW, when the diode voltage is taken in the range 520-540kV, and the diode current is in the range 58-62kA. This confirms the simulation results.     

Volt-ampere characteristics of a nitrogen DC plasma arc with anode melting

The characteristics of a nitrogen arc using a graphite cathode and a melting anode in a pilot-scale plasma furnace are investigated. The voltage is examined as a function of current and apparent plasma length. The voltage increases non-linearly with the increase of apparent plasma length, with the current fixed. The experimental data so obtained are compared with the predictions of the Bowman model for the electric arc, and with numerical simulations as well. The level of agreement between the experimental data at the melting anode and the numerical predictions confirms the suitability of the proposed the Bowman model. These characteristics are relevant to the engineering design and evaluation of a DC plasma furnace and reactor for the treatment of hazardous fly ash waste.     

一类具有Markov性质的混沌系统的构造

本文构造了一类具有Markov性质的分段扩张线性映射, 计算表明其具有正的李雅普诺夫指数. 通过理论分析, 证明了其极限分布是均匀分布, 并给出了其最小周期的计算公式. 通过分析符号熵测度应用于此系统时的具体涵义, 指出该系统的复杂度与系统的最小周期之间存在着矛盾关系, 说明了此系统具有可控的复杂度并给出了其复杂度随系统参数变化时的理论极限公式. 通过统计测试和复杂度测试表明, 此系统产生的混沌序列服从均匀分布, 而通过参数的调整该系统的符号熵可以接近其理论极限, 而与Logistic映射和斜帐篷映射的基于近似熵和符号熵的对比实验可知, 本文所提系统具有更高的复杂度, 并有更长的最小周期. 这表明此系统比较适合用于构造保密通信系统. 关键词： 混沌 Markov性质 复杂度 均匀分布     

生物材料冻存中低温保护剂的作用机理及实验研究

生物材料在冻存过程中保存液内加载低温保护剂可以减轻降温和复温时对细胞的损伤。介绍了低温保护剂的种类及其特点,分析了低温保护剂的作用机理。实验结果表明,选择合适的低温保护剂及其浓度,可以大大提高生物细胞的存活率。     

旋转独轮车

<正>准备材料和工具胶带圈、彩纸、白纸、棉签、吸管、双面胶、热熔胶、手工刀、剪刀、彩笔制作步骤1准备一个胶带圈,在胶带圈上贴一圈双面胶并揭开。2裁一张1.2 cm×15 cm的长方形彩纸,将彩纸贴在双面胶上。3去掉棉签上的棉花,将棉签切成两段,每段长约2.5cm。     

Guided transmission of oxygen ions through Al2O3 nanocapillaries

The transmissions of oxygen ions through Al2O3 nanocapillaries each 50 nm in diameter and 10 μm in length at a series of different tilt angles are measured,where the ions with energies ranging from 10 to 60 keV and charge states from 1 up to 6 are involved.The angular distribution and the transmission yields of transported ions are investigated.Our results indicate both the existence of a guiding effect when ions pass through the capillary and a significant dependence of the ion transmission on the energy and the charge state of the ions.The guiding effects are observed to be enhanced at lower projectile energies and higher charge states.Meanwhile,the results also exhibit that the transmission yields increase as the tilt angle decreases at a given energy and charge state.