一种强力钻地弹侵彻混凝土靶研究

设计了一种更为强力的钻地弹-钨镇重钻地弹,以提高钻地弹对硬介质目标的侵彻能力。将特殊设计的钨合金结构作为镇重体填加至钻地弹的壳体内部,以提高钻地弹的整体密度,增大面质量,从而提高了钻地弹的侵彻能力。设计了实验用靶、可分离弹托和尾翼,成功进行钨镇重钻地弹缩比弹侵彻混凝土靶的实验室实验和外场实验,并进行了相同条件下普通钻地弹缩比弹对比侵彻实验。实验结果表明:相对于普通钻地弹,钨镇重钻地弹的侵彻能力有了较大幅度的提高;钨镇重钻地弹的弹体结构强度设计满足侵彻需要,弹体在侵彻过程中能有效生存。采用实验的方法研究了缩比率对钻地弹侵彻深度的影响,对钻地弹侵彻深度相似律进行了修正。根据相似律的研究结果,钻地弹的侵彻深度与缩比率成正比关系,但是,该结论忽略了侵彻过程中靶介质动态强度应变率效应的影响。进行了大量的不同缩比率的实验,并收集了相关的实验数据,分析认为,钻地弹的侵彻深度与缩比率呈1.15次方关系。该结论有助于通过缩比实验结果较为准确的预估原型弹的侵彻能力。     

A thin and compact compound-eye imaging system incorporated with an image restoration considering color shift, brightness variation, and defocus

A compact system of the thin observation module by bound optics (TOMBO) imager based on compound-eye imaging has been constructed to demonstrate its advantages over single-eye imaging systems such as thinner hardware. To reconstruct a high-resolution image from low resolution images captured by the compound-eye optics, we propose an image restoration scheme based on the iterative back-projection algorithm with depth map estimated from the disparities on the captured image. The scheme includes suppression of unit-by-unit color shift caused by the offset microlenses and the color filters on the commercial image sensors and deblurring of defocus by geometrical optics using the depth map. In the experiment, three-dimensional objects were captured by the TOMBO imager and reconstructed with the scheme. After the processing, the power spectrum of the captured image was improved by up to 19 dB, and the power spectrum of the effect of the color shift was reduced by 7 dB.     

On a robust and efficient maximum depth estimator

The best breakdown point robustness is one of the most outstanding features of the univariate median. For this robustness property, the median, however, has to pay the price of a low efficiency at normal and other light-tailed models. Affine equivariant multivariate analogues of the univariate median with high breakdown points were constructed in the past two decades. For the high breakdown robustness, most of them also have to sacrifice their efficiency at normal and other models, nevertheless. The affine equivariant maximum depth estimator proposed and studied in this paper turns out to be an exception. Like the univariate median, it also possesses a highest breakdown point among all its multivariate competitors. Unlike the univariate median, it is also highly efficient relative to the sample mean at normal and various other distributions, overcoming the vital low-efficiency shortcoming of the univariate and other multivariate generalized medians. The paper also studies the asymptotics of the estimator and establishes its limit distribution without symmetry and other strong assumptions that are typically imposed on the underlying distribution. This work was supported by Natural Science Foundation of USA (Grant Nos. DMS-0071976, DMS-0234078) and by the Southwestern University of Finance and Economics Third Period Construction Item Funds of the 211 Project (Grant No. 211D3T06)     

On a robust and effcient maximum depth estimator

The best breakdown point robustness is one of the most outstanding features of the univariate median.For this robustness property,the median,however,has to pay the price of a low effciency at normal and other light-tailed models.Affine equivariant multivariate analogues of the univariate median with high breakdown points were constructed in the past two decades.For the high breakdown robustness,most of them also have to sacrifice their effciency at normal and other models,nevertheless.The affine equivariant...     

Report on the 47th IUVSTA Workshop ‘Angle‐Resolved XPS: the current status and future prospects for angle‐resolved XPS of nano and subnano films’

A summary of the workshop entitled ‘Angle‐Resolved XPS: The Current Status and Future Prospects for Angle‐resolved XPS of Nano and Subnano Films’ is given, which was held at the Riviera Maya, Mexico, 26–30 March 2007, under the main sponsorship of the International Union for Vacuum Science, Technique and Applications (IUVSTA). Angle‐resolved X‐ray photoelectron spectroscopy (ARXPS) can provide detailed chemical as well as depth profile information about the near‐surface composition of materials and thin films. This workshop was held to review the present status and level of understanding of Angle‐resolved XPS, and to stimulate discussions leading to a deeper understanding of current problems and new solutions. The main goal of the workshop was to find better ways to perform experiments and, very importantly, better ways to extract information from the experimental data. This report contains summaries of presentations and discussions that were held in sessions entitled ‘Basics and Present Limits of ARXPS’, the Analysis of ARXPS Data, Applications of ARXPS, Equipment for ARXPS, and Future Developments in ARXPS'. There were 33 participants at the workshop. Copyright © 2009 John Wiley & Sons, Ltd.     

Estimating error bounds for quaternary subdivision schemes

This paper deals with the error estimation techniques of quaternary subdivision schemes. The estimation is expressed in terms of initial control point sequences and constants. It is independent of subdivision process and parametrization therefore its evaluation is straightforward.     

一种斜视FMCW SAR的等效正侧视处理方法

本文分析了斜视调频连续波SAR中载机连续运动的影响——产生多普勒频移,以及其对图像聚焦的影响,建立了斜视调频连续波SAR信号模型,在分析了现有频率变标算法在斜视角较大情况下失效根源的基础上,提出了一种斜视数据等效正侧视处理方法,通过对斜视数据的预处理,将斜视数据按正侧视的方法来处理;针对预处理带来的方位聚焦深度的制约,采用方位非线性调频变标处理克服方位聚焦深度的限制.最后通过点目标仿真数据处理验证所提算法的有效性.     

基于距离向量深度的多约束路径选择算法

 为各种应用提供不同的服务质量(Quality of Service,QoS)保证是下一代高速网络面临的一个重要难题,而服务质量路由(Quality of Service routing,QoSR)则是其中的一项核心技术.本文针对不精确状态信息下的多约束QoSR问题,建立了一种用于求解此类多约束QoSR问题的临界点模型,提出了一种基于距离向量深度的多约束QoS路径选择算法(MCPSA),该算法以已有的QoS路由预计算算法为基础,设法选择一条能够最大程度适应不精确网络状态信息的路径,理论分析表明该算法具有一定的优势.最后,结合已有的路由预计算算法进行了大量的仿真试验,结果表明MCPSA具有很强的问题求解能力,能够有效克服路由状态信息的不确定性.     

300 mm硅片表面延性磨削机理研究

根据脆性材料实现延性磨削时存在临界深度的理论,通过设定磨削参数,使之满足硅片的延性磨削条件.利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)对磨削硅片表面和截面进行分析研究.研究结果表明:硅片表面形成规律的磨削印痕,且磨削印痕微弱,在硅片表面留下的磨削沟槽保留延性磨削特征,硅片表面无微细裂纹和因脆性崩裂产生的凹坑;硅片截面明显地分为非晶层、次表面损伤层、单晶硅层,非晶层厚度约为50～100 nm,表面微细裂纹完全消失,次表面损伤层厚度约为50～150 nm,次表面损伤层存在微细裂纹.     

采用图像修复的基于深度图像复制

在传统的基于深度图像复制(DIBR)的基础上提出一种基于图像修复的DIBR方法,将预处理深度图像和图像修复算法相结合来填补三维图像映射后的空洞。与传统方法相比更加灵活,本文方法仅需传输一路参考图像序列,从而有效降低DIBR系统的传输带宽。实验结果证明,本文所提出方法是有效的。