Simulation and experimental study of chaos generation in microwave band using Colpitts circuit

Chaotic Colpitts circuits with fundamental frequency f^＊ beyond 1GHz are studied by both circuit simulation and experiment using Philips＇ broadband transistor with threshold frequency of 25GHz. For the basic configuration of Colpitts circuit with f^＊ of about 1,6GHz, broadband continuous power spectra could be obtained from both circuit simulations and experiments. The harmonics of the observed signal from Agilent PSA/ESA spectrum analyzer are as noticeable as far as 12GHz. A modified Colpitts circuit structure employing the parasitic inductance of BJT （Bipolar Junction Transistor） is also proposed and investigated. By circuit simulation, chaotic attractor and broadband continuous power spectra could be obtained from the modified Colpitts circuit with f^＊ of about 3.5GHz. Because the parasitic effects of the prototype board, the experiment result of the modified Colpitts circuit does not agree well with the simulation result. The gap between the simulation and experimental result could be bridged by replacing the lumped circuit elements with distributed ones.     

离差偏好法在舰载直升机保障能力评估中的应用

考虑到目前我国舰载直升机保障能力评估方面存在数据不完整、评估中需要考虑决策者偏好的问题,研究了基于离差偏好法的舰载直升机保障能力评估模型。在通过调研并考虑舰载直升机保障实际情况的基础上,构建了保障能力评估指标体系,并根据决策者的偏好建立了评估对象的互反判断矩阵;在保障能力评估中运用了离差偏好法,从对评估对象进行排序的角度对各个指标的权重进行了重新定义,建立了量值与偏好矩阵的偏差函数,通过实例分析表明该模型实用性较强,过程简单,适合现阶段舰载直升机保障能力评估问题的研究,具有一定的应用价值。     

An Intrinsically Nonflammable Electrolyte for Prominent-Safety Lithium Metal Batteries with High Energy Density and Cycling Stability

Nex-generation high-energy-density storage battery, assembled with lithium (Li)-metal anode and nickel-rich cathode, puts forward urgent demand for advanced electrolytes that simultaneously possess high security, wide electrochemical window, and good compatibility with electrode materials. Herein an intrinsically nonflammable electrolyte is designed by using 1 M lithium difluoro(oxalato)borate (LiDFOB) in triethyl phosphate (TEP) and N-methyl-N-propyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide [Pyr₁₃][TFSI] ionic liquid (IL) solvents. The introduction of IL can bring plentiful organic cations and anions, which provides a cation shielding effect and regulates the Li⁺ solvation structure with plentiful Li⁺-DFOB⁻ and Li⁺-TFSI⁻ complexes. The unique Li⁺ solvation structure can induce stable anion-derived electrolyte/electrode interphases, which effectively inhibit Li dendrite growth and suppress side reactions between TEP and electrodes. Therefore, the LiNi_0.9Co_0.05Mn_0.05O₂ (NCM90)/Li coin cell with this electrolyte can deliver stable cycling even under 4.5 V and 60 °C. Moreover, a Li-metal battery with thick NCM90 cathode (≈ 15 mg cm⁻²) and thin Li-metal anode (≈ 50 µm) (N/P ≈ 3), also reveals stable cycling performance under 4.4 V. And a 2.2 Ah NCM90/Li pouch cell can simultaneously possess prominent safety with stably passing the nail penetration test, and high gravimetric energy density of 470 Wh kg⁻¹ at 4.4 V.     

基于PCI总线的高速多路数据传输卡设计

介绍了一套基于外部设备互连(PCI)总线的高速多路数据传输卡的设计,采用基于PCI内核与PCI用户逻辑相结合的新型设计方案,在顶层通过仿真来验证PCI接口以及用户逻辑设计正确与否.降低了设计的复杂程度,提高了电路的集成度和系统的性能,并根据PCI卡对外部设备驱动能力较弱的特点,在传输卡中加入了长线驱动功能,采用低电压差分信号(LVDS)技术,既降低了系统功耗,又实现长距离的计算机双向通信.     

PCI接口控制器CY7C09449及其应用

CY7C89449是Cypress公司开发的PCI协议主/从模式接口控制器.介绍了其功能特点及应用,并说明了引脚功能及配置注意事项.给出了一个机械手控制卡电路实例,旨在介绍如何利用CY7C09449实现PCI与TMS320C6711之间的数据传输.     

Experiment demonstration of micro-Doppler detection of rotor blades with passive coherent location based on digital video broadcast

We propose a realtime passive coherent location (PCL) system based on digital video broadcast (DVB) for the detection of the micro-Doppler (m-D) signature induced by the blades of a helicopter. In this paper, the detailed demonstration of the hardware system, signal processing and field experiment is presented. The m-D parameters of the model helicopter in the experiment are accurately estimated by means of cross ambiguity function (CAF). This paper contributes additional experimental m-D data and analysis, and the effectiveness of micro-motion detection by PCL system is well proved. The attractive merits of DVB based PCL make it more feasible to be widely deployed in urban environment for homeland security purpose. The present work is the first reported realtime system of DVB based PCL for the m-D detecting purpose.     

一种内容中心网络传输内容冗余的消除方法

为了减少互联网中传输数据包的大量冗余信息,减少网络流量,提高网络带宽利用效率,研究利用内容中心网络特殊的通信方式及路由器的内容缓存能力,提出一种内容中心网络(CCN)中网络级的传输内容冗余消除方法,在CCN中实现网络级的传输内容冗余消除。并通过仿真分析,验证了该方法可以有效地减少CCN网络中的流量。     

云参数和可降水总量的同步物理反演方法试验

利用改进的同步物理反演方法计算东亚地区的云参数和可降水总量,并用气象卫星短、长波窗区通道亮度温度差对反演结果进行真实性检验.结果表明:该反演算法的效果是好的.     

ATM网络异种复用业务信元丢失率快速估计的新算法

ＡＴＭ网络信元丢失率（ＣＬＲ）的估计是呼叫接入和流量控制的关键技术,基于信元丢失机制的分析,本文了一种改进的简单业务模型,并进而得到一种新的算法,能够对异种混合业务复用的ＡＴＭ网络进行快速的ＣＬＲ估计,该算法处理速度快,能够做到呼叫的实时响应,模型采用国际规范的标准参数构造,可以直接应用于实际操作,仿真结果表明,算法的精度,运算复杂度和算法鲁棒性都比较理想,具有较高的实用价值。     

基于热释电红外传感器的火灾探测系统设计

介绍了热释电红外传感器的结构、工作原理及特点;设计了一个基于此类传感器的红外火灾探测系统;运用BP神经网络分析了火灾识别算法;促进了消防技术的发展.