红外系统对飞行弹丸探测地点选取的模型方法

红外系统捕获飞行弹丸时,必须保证该系统对飞行弹丸的作用距离大于弹丸到红外系统的距离,分析了传统的红外系统作用距离计算公式,考虑了弹丸在飞行过程中与红外系统之间的距离会随着飞行时间变化,而红外辐射在大气中的衰减随着波长和传输距离不同而变化,因此红外系统接收到的弹丸辐射会在弹丸飞行过程中随着时间而变化;同时考虑到弹丸在飞行中系统接收的红外辐射受天空背景影响和弹丸截面等效面积的辐射影响,从而重新提出了红外系统的作用距离模型。在简单弹道模型的基础上,计算并分析理论飞行距离与系统作用距离相互影响的关系,获得红外系统对弹丸发射过程捕获的最佳位置,为红外系统探测飞行弹丸的地点选取提供理论依据。     

Subpicosecond Domain Switching in Discrete Regions of Pb(Zr0.35Ti0.65)O3 Thick Films

The time dependence of the domain switching current density, J_sw(t), under pulsed voltages on a ferroelectric parallel‐plate capacitor is the consequence of region‐by‐region polarization reversals across the film. As the distributive coercive voltage of domain nucleation increases from zero to the maximum applied voltage during the capacitor charging time, J_sw(t) is proportional to the domain switching speed at each time. By transforming the spatially inhomogeneous domain nucleation distribution into a temporal distribution of coercive fields (E_c), a local lnJ_sw versus E_c^?1 plot is derived for each domain, following the Merz equation. This provides insight into the independent domain switching dynamics at different nucleation sites in Pb(Zr_0.35Ti_0.65)O₃ thick films over a large current range. Although the activation field of the slope of the lnJ_sw(t) versus E_c^?1 plot varies with film area and temperature, all the plots extrapolate to a single point (J₀, E₀) from which the ultimate domain switching current density of J₀ =1.4 × 10⁸ A cm^?2 at the highest field of E₀ = 0.20‐0.25 MV cm^?1 is derived. Unexpectedly, J₀ and E₀ are independent of the film thickness and area, after correction for a small interfacial‐layer effect. This analysis provides rigorous evidence for nucleation rate‐limited domain switching with a subpicosecond nucleation time and the relative unimportance of domain forward‐growth time across film thicknesses between 0.14 and 2 μm. This work paves the way to improve the efficiency of ferroelectric thick‐film functionality in electronic and optoelectronic devices with ultrafast clock rates.     

量子器件的计算机模拟

综述了量子器件的几种输运模型及其模拟结果 ,并对量子器件物理模型及其辅助设计提出了设想。     

一种可拨打IP视频电话的电视机设计

提出了一种在电视机平台上添加视频电话模块,成为可拨打IP视频电话的电视机解决方案.该方案的电视主平台采用的是Trident WX68平台.视频电话模块采用的是TI公司的TMS320DM6446芯片平台,并通过测试证明该设计的可行性.     

A Low Loss X-Band Quasi-Elliptic Ferroelectric Tunable Filter

A compact high quality factor four-pole X-band tunable quasi-elliptic bandpass filter is presented in this letter. The filter is enabled by high-Q ferroelectric barium strontium titanate capacitors and open-loop resonators. The central frequency of 8.35 GHz and the frequency tuning range of 500 MHz (6%) are achieved with a dc bias voltage of 30 V. The selective filter has a fractional 1 dB bandwidth ranging from 5.5% up to 7.3%. The measured insertion loss and return loss are 5.7-3.5 dB and 10.2-7.9 dB, respectively, with a dc bias range of 0 to 30 V. To the best of our knowledge, this is the best analog tunable performance and selectivity in X-band.     

基于有限新息率采样理论的超宽带信道估计

提出利用有限新息率采样理论解决超宽带信道估计问题,建立了可用于超宽带信道估计的框架,此框架的抽样率低于奈奎斯特速率.通过实例展示了科用奈奎斯特速率抽样而工作在低于奈奎斯特抽样率的算法性能,减少了功耗,也降低了硬件的复杂性.     

强脉冲光短接触光动力疗法在痤疮治疗中的应用

目的:观察强脉冲光短接触光动力疗法的临床疗效及安全性.方法: 选取12例轻中度痤疮患者进行临床观察,在应用氨基乙酰丙酸30分钟后应用强脉冲光治疗,观察治疗过程中及治疗结束后的副反应及疗效.结果: 经四次治疗后患者炎性皮疹明显减少,治疗区皮脂分泌量下降,皮肤含水量无明显改变,治疗中及治疗后未发生色沉等严重副反应.结论: 强脉冲光短接触光动力疗法是一种安全有效的痤疮治疗方案.     

Printed stretchable circuit on soft elastic substrate for wearable application

In this paper,a flexible and stretchable circuit has been fabricated by the printing method based on Ag NWs/PDMS composite.The randomly oriented Ag NWs were buried in PDMS to form a conductive and stretchable electrode.Stable conductivity was achieved with a large range of tensile strain (0-50％) after the initial stretching/releasing cycle.The stable electrical response is due to the buckling of the Ag NWs/PDMS composite layer.Furthermore,printed stretchable circuits integrated with commercial ICs have been demonstrated for wearable applications.     

M4K块移位寄存器数据读进方式的逻辑分析仪设计

采用Altera公司的Cyclone系列EP1C3T144C8作为控制芯片,QuartusⅡ为软件平台,用硬件描述语言设计了一个具有变频采样时钟和16路采样通道,基于VGA显示的逻辑分析仪.该设计方案利用FPGA内部的M4K块作为移位寄存器不断地进行读进数据的方式,提高了工作速度、性能稳定性以及分析的范围和质量.该逻辑...     

一种波长共享WDM-PON系统

介绍了一种采用星型耦合器和阵列波导光栅构成的波长共享型复合WDM/TDM-PON光接入网系统,并针对该系统提出了一种防止上行信道中波长冲突的简单快速检测方法,采用硬件检测接收端光功率门限的方法,可以避免目前常用的OLT轮询ONU而导致传输信号的延迟,提高传输带宽.实验测试控制延迟在10ms内.