双像双视场红外光学系统

介绍了一种双像双视场红外光学系统,对其设计方法、分光原理和分光元件进行了深入讨论.由于使用了孔径分光、光楔对双视场图像进行空间分离、二向色性分束镜进行光谱细分,两光路合一,使卡塞格林光学系统的潜力得到了充分发挥,实现了共窗口、共探测器的双像双视场成像光学系统.系统能提供一幅场景的两幅图像,两视场之间无需切换,两视场具有不同的光谱波段.通过电子系统的波段比处理技术,能提高整机系统的抗干扰能力,提高整机系统的探测精度和识别概率.     

基于MOCCCII的双模式二阶通用滤波器

提出了一种基于多输出端口电流控制电流传输器(MOCCCII,multiple outputs current controlled conveyor)的双模式二阶通用滤波器,该滤波器结构简单,仅由5个有源器件、2个接地电容构成, 无须外接电阻.该电路在不改变内部电路结构的情况下能实现电压模式和电流模式滤波器,且每一种工作模式都能实现高通、低通、带通等多种滤波功能,因此该电路具有通用性.面向实际电路完成了PSPICE仿真,结果表明提出的电路正确有效.     

Flexible Transparent Reduced Graphene Oxide Sensor Coupled with Organic Dye Molecules for Rapid Dual‐Mode Ammonia Gas Detection

Flexible chemical sensors utilizing chemically sensitive nanomaterials are of great interest for wearable sensing applications. However, obtaining high performance flexible chemical sensors with high sensitivity, fast response, transparency, stability, and workability at ambient conditions is still challenging. Herein, a newly designed flexible and transparent chemical sensor of reduced graphene oxide (R‐GO) coupled with organic dye molecules (bromophenol blue) is introduced. This device has promising properties such as high mechanical flexibility (>5000 bending cycles with a bending radius of 0.95 cm) and optical transparency (>60% in the visible region). Furthermore, stacking the water‐trapping dye layer on R‐GO enables a higher response as well as workability in a large relative humidity range (up to 80%), and dual‐mode detection capabilities of colorimetric and electrical sensing for NH₃ gas (5–40 ppm). These advantageous attributes of the flexible and transparent R‐GO sensor coupled with organic dye molecules provide great potential for real‐time monitoring of toxic gas/vapor in future practical chemical sensing at room conditions in wearable electronics.     

受控源“电阻性”和“有源性”的研究

首先对受控源的电阻性和有源性进行了分析,然后比较完整系统地讨论了受控源的双重特性在线性时不变含受控源网络中的作用,并通过实例说明了受控源的双重特性在电路等效变换以及叠加定理中的具体的应用。     

A study of gridless method with dynamic clouds of points for solving unsteady CFD problems in aerodynamics

When solving unsteady computational fluid dynamics problems in aerodynamics with a gridless method, a cloud of points is usually required to be regenerated due to its accommodation to moving boundaries. In order to handle this problem conveniently, a fast dynamic cloud method based on Delaunay graph mapping strategy is proposed in this paper. A dynamic cloud method makes use of algebraic mapping principles and therefore points can be accurately redistributed in the flow field without any iteration. In this way, the structure of the gridless clouds is not necessarily changed so that the clouds regeneration can be avoided successfully. The spatial derivatives of the mathematical modeling of the flow are directly determined by using weighted least‐squares method in each cloud of points, and then numerical fluxes can be obtained. A dual time‐stepping method is further implemented to advance the two‐dimensional Euler equations in arbitrary Lagarangian–Eulerian formulation in time. Finally, unsteady transonic flows over two different oscillating airfoils are simulated with the above method and results obtained are in good agreement with the experimental data. Copyright © 2009 John Wiley & Sons, Ltd.     

无线双模数字对讲机的设计与实现

传统模拟对讲机由于频谱利用率低、抗干扰性能差、频道开放、不具有保密性等原因已经很难满足需求。文章介绍的无线双模对讲机用于改善传统模拟对讲机抗干扰及保密性差的缺点,所提双模对讲机设计方案综合了集群和无中心两种工作模式功能,具有灵活设置与抗干扰性强的优点。文中重点设计了对讲机的软硬件结构,还对音频编解码进行了讨论分析。     

Operators on the orthogonal complement of the Dirichlet space(Ⅱ)

In this paper we first prove that a dual Hankel operator R φ on the orthogonal complement of the Dirichlet space is compact for φ∈ W 1,∞(D),and then that a semicommutator of two Toeplitz operators on the Dirichlet space or two dual Toeplitz operators on the orthogonal complement of the Dirichlet space in Sobolev space is compact.We also prove that a dual Hankel operator R φ with φ∈ W 1,∞(D) is of finite rank if and only if B φ is orthogonal to the Dirichlet space for some finite Blaschke product B,and give ...