透镜球差对拉盖尔-高斯涡旋光束聚焦特性的影响及改善方法

涡旋光场调控对涡旋光在激光通信、生物操控等领域的应用研究具有重要意义。为了揭示透镜球差对拉盖尔-高斯(Laguerre-Gaussian,LG)涡旋光束传输特性的影响,本文基于菲涅尔衍射理论,模拟研究了不同透镜球差系数下的LG光束聚焦场的强度、相位以及螺旋谱分布。结果表明:光学系统初级球差系数的增大恶化了LG光束聚焦场的强度分布和螺旋相位,弥散了轨道角动量(orbital angular momentum,OAM) 。由此,本文提出了一种光阑补偿方案,通过在透镜前添加大小合适的圆孔光阑,以消除透镜像差。光阑补偿后的LG光束聚焦场由星芒状空心分布恢复为空心圆环分布,OAM态保持单一稳定。本研究工作为改善透镜像差对涡旋光的传输影响提供了解决方案。     

六面顶金刚石压机自动控制系统

本文针对六面顶金刚石压机的复杂工艺流程特点,设计研发了一套六面顶金刚石压机计算机自动控制系统。该系统主要包括硬件结构设计和软件设计两部分。软件部分主要解决了压机的定位控制与同步调整问题,并给出了工艺曲线设定方法、控制算法及其主要运行结果。该控制装置与某超硬材料公司六面顶金刚石压机及相关液压系统配套组成金刚石全自动生产装置,实现了全视窗界面、触摸屏操作,控制算法新颖,图形界面良好,控制精度高,保证了合成金刚石的品级。     

MODELING METHOD OF 4D INFORMATION MODEL FOR COOPERATIVE DESIGN OF MECHANICAL PRODUCTS

The continuous developing features in the design of mechanical product and based on 3D entity model is aimed at, and the extension of the 4-dimensional model with the process of designing, the knowledge described model on the level of semantic understanding and summarizing the designing process and the way of discovering knowledge from multi-information model are studied. On the basis of designing the broad sensed collaborative system, through discussion of the relationship between the implicit knowledge of the users and the designing knowledge as well as commanding all the designing links, taking advantage of the way of concluding and deducting in the concept of the designers, the synthetic knowledge unit formed in the dynamic process from the conception design to the last design is schemed out, and the knowledge discovered principle in the dynamic designing process of the mechanical products and the key technology in its implementation under the milieu of network is brought forward.     

Ob ject-Based Classification Metho d for PolSAR Images with Improved Scattering Powers and Contextual Features

This paper proposes a new object-based classification method for Polarimetric synthetic aperture radar (PolSAR) images, which considers scattering powers from an improved model-based polarimetric decomposition approach, as well as the spatial and textural features. With the decomposition, the scattering ambiguities between ori-ented buildings and vegetation are reduced. Furthermore, various contextual features are extracted from the ob ject and incorporated into the K-nearest neighbors (k-NN) based classification. To reduce the feature redundancy, a new Supervised locally linear embedding (S-LLE) dimen-sionality reduction method is introduced to map the high dimensional polarimetric signatures into the most compact low-dimensional structure for classification. Experimental results with Airborne synthetic aperture rada (AIRSAR) C-band PolSAR image demonstrate the superior perfor-mance to other methods.     

星载-机载混合双站SAR回波信号的仿真

对于星载-机载双站合成孔径雷达（SA-BiSAR）系统,回波模拟的关键是计算出卫星、飞机和目标这三者之间的距离。在考虑地球自转的情况下,提出了用坐标变换的方法,解决了近地空间与外太空之间距离的计算问题,实现了任意几何模型下更为精确的SA-BiSAR回波模拟。同时,利用此方法也可获得直达波信号。点目标的仿真展示了SAR回波信号的特征,该方法得到了验证。     

合成射流激励影响扩散燃烧NOx生成的实验研究

对合成射流激励助燃风影响NOx生成进行了实验研究,主要考察了合成射流频率、幅值对燃烧器内掺混区时均速度、NOx含量、温度等参数分布的影响。实验结果表明,加入适当频率的合成射流激励助燃风,能够增强径向、周向速度幅值,改善天然气与助燃风的掺混,降低“热点”温度和NOx生成量（较无激励时最多降低约14％）,这有益于降低天然气燃烧造成的大气污染。     

Smaller,Stronger, More Stable: Peptide Variants of a SARS-CoV-2 Neutralizing Miniprotein

Based on the structure of a de novo designed miniprotein (LCB1) in complex with the receptor binding domain (RBD) of the SARS-CoV-2 spike protein, we have generated and characterized truncated peptide variants of LCB1, which present only two of the three LCB1 helices, and which fully retained the virus neutralizing potency against different SARS-CoV-2 variants of concern (VOC). This antiviral activity was even 10-fold stronger for a cyclic variant of the two-helix peptides, as compared to the full-length peptide. Furthermore, the proteolytic stability of the cyclic peptide was substantially improved, rendering it a better potential candidate for SARS-CoV-2 therapy. In a more mechanistic approach, the peptides also served as tools to dissect the role of individual mutations in the RBD for the susceptibility of the resulting virus variants to neutralization by the peptides. As the peptides reported here were generated through chemical synthesis, rather than recombinant protein expression, they are amenable to further chemical modification, including the incorporation of a wide range of non-proteinogenic amino acids, with the aim to further stabilize the peptides against proteolytic degradation, as well as to improve the strength, as well the breadth, of their virus neutralizing capacity.     

边际油田群的综合开发

本文回顾了国内外海上边际油田群的开发状况,从减少开发投资和提高油田群开发的经济性出发,提出了适合边际油田综合开发的技术和开发策略,简要介绍了边际油田群综合开发的最新研究动态。     

某型导弹发控盒电路板综合测试系统的设计

介绍了某型导弹发控盒电路板综合测试系统的硬件和软件设计,该系统以PC计算机为平台,采用总线式设计思想,实现了对电路板检测的自动化、快速化和智能化.     

一种快速直接的长码捕获方法

传统的PMF-FFT算法用于直接长码捕获时,每次只能搜索一个码片相位,FFT的运算次数较多,捕获时间长,大步进PMF-FFT算法每次可以搜索多个码片相位,减小FFT的运算次数,从而加快了捕获速度.实验结果表明,该算法在长码捕获过程中能取得良好的捕获性能,具有广阔的应用前景.