Decorative near-infrared transmission filters featuring high-efficiency and angular-insensitivity employing 1D photonic crystals

We present a new scheme for visibly-opaque but near-infrared-transmitting filters involving 7 layers based on one-dimensional ternary photonic crystals, with capabilities in reaching nearly 100% transmission efficiency in the near-infrared region. Different decorative reflection colors can be created by adding additional three layers while maintaining the near-infrared transmission performance. In addition, our proposed structural colors show great angular insensitivity up to ±60° for both transverse electric and transverse magnetic polarizations, which are highly desired in various fields. The facile strategy described here involves a simple deposition method for the fabrication, thereby having great potential in diverse applications such as image sensors, anti-counterfeit tag, and optical measurement systems.

     

复合材料压缩破坏模式的缺陷敏感性

本文基于弹塑性分叉理论研究单向纤维增强复合材料的压缩破坏模式和压缩强度对缺陷的敏感性问题。对于常见复合材料,所得结论是:无缺陷或者小缺陷情况的破坏模式为倾斜破坏带;大缺陷情况的破坏模式为水平破坏带;形成水平破坏带的压力值小于形成倾斜破坏带的压力。     

圆坯连铸机高效化实践

通过对圆坯连铸机工艺措施的优化,以及新材料、新技术的应用,包钢圆坯连铸机的连浇炉数大幅度提高,实现了连铸机的高效化生产.     

一种改进的量子蚁群算法及其应用

将量子群进化算法（QEA）与蚁群系统（ACS）进行融合,提出一种新的量子蚁群算法（QACA）。该算法的核心是在蚁群系统（ACS）中引入量子算法中的量子的态矢量和量子旋转门来分别表示和更新信息素,从而在全局寻优能力和种群多样性方面比蚁群算法有所改进。结合旅行商问题（TSP）,对算法进行了测试,得到了与现有文献结果相同或更好的解,表明该算法具有较强的问题求解能力。     

PKMvl协议研究

IEEE 802.16的安全子层采用了认证客户端/服务器密钥管理协议,在该协议中基站(即服务器)能够对分发给客户端SS的密钥进行控制.IEEE 802.16系列标准的安全主要基于PKM协议.在初始授权密钥交换期间,BS使用基于数字证书的ss认证.来对客户端ss进行认证.PKM协议使用公钥密码技术来建立SS与BS之间的共享密钥,SS也使用PKM协议来支持周期性重认证和密钥更新.本文首先分析了PKMvl中安全子层的协议栈,然后给出了WiMAX安全关联的种类与内容,研究了WiMAX安全流程以及安全认证、密钥交换和数据加密等方案.最后,对PKMvl可能存在的安全威胁进行了详细的介绍.     

Fracture Characteristics and Damage Evolution of Coating Systems Under Four‐Point Bending

The fracture and damage behaviors of ceramic coating/alloy substrate systems under four‐point bending were investigated using a scanning electron microscope to observe in situ tests. Both the thin and thick coatings fractured by tensile instability at the pure bending sections, and multiple transverse cracks that were vertical to the interface occurred in the coatings. The average crack spacing was greater for the thick coatings than for the thin ones. A catastrophic failure model was developed to explain the damage evolution behavior of the coatings. The damage was found to increase sharply near the failure point.     

进给速率对 AlSi/PHB 封严涂层可磨耗性的影响

可磨耗封严涂层是应用在航空发动机中从而提升其效率的一种材料。本文采用模拟工况法,利用自主研制的BGRIMM-ATR型高温超高速可磨耗试验机对AlSi/PHB封严涂层进行了不同进给速率下的可磨耗实验,研究进给速率变化对AlSi/PHB封严涂层可磨耗性的影响,利用体式显微镜、扫描电子显微镜(SEM)分析涂层的宏观和微观形貌,并利用多种表征方式进行可磨耗性的综合评价。结果表明:在常温下,线速度350 m/s,进给深度500μm的情况下,进给速率由低到高增长时,AlSi/PHB涂层的可磨耗性呈现一个先增高后降低的趋势,进给速率的改变对AlSi/PHB的相对可磨耗性影响明显。在中等进给速率时可磨耗性优秀,主要表现为切削机制;在低进给速率和高进给速率时,涂层可磨耗性有所降低,主要表现为涂层深犁沟、裂痕、碎屑,主要机制为犁削、熔融和碰撞撕裂等。     

Surface Deformation Measurement by Phase-Shift Holographic Interferometry

In this paper, the principle of phase-shift interferometry is first briefly introduced. Then it is used as an illustration to measure small surface deformation, and the measurement accuracy of 0.02μis obtained. This demonstrates that the technology has great significance for strain analysis in experimental mechanics.     

青塔住宅区规划的创作体会

青塔住宅区是北京西站拆迁小区,面积较大(约60公顷),属市重点工程。作者对该区的规划设计,经市规委优选定为实施方案。本文对青塔住宅区规划的环境设计、道路网络、住宅布局,绿化美化等方面的构思和体会做了全面阐述,可供有关专业人员借签参考。     

一种宽带贴片天线的设计与仿真

介绍了微带贴片天线的特点、原理和设计方法，针对孔径耦合的馈电方式，运用以有限元法为原理的软件对设计的贴片天线进行仿真，并对天线参数进行优化，结果表明孔径耦合微带贴片天线结构简单，可以达到21％的相对带宽（VSWR〈2），和较高的增益。同时对影响天线性能的主要参数进行仿真对比，得出了实用性的结论，对方便有效地改进电子对抗装备性能有一定的意义。