一种高功率LED封装的热分析

建立了大功率发光二极管(LED)器件的一种封装结构并利用有限元分析软件对其进行了热分析,比较了采用不同材料作为LED芯片热沉的散热性能.最后分析了LED芯片采用chip-on-board技术封装在新型高热导率复合材料散热板上的散热性能.     

新型耐高温导线的研制

根据新型耐高温导线的主要性能技术要求，设计了镀镍铜线＋高硅氧玻璃纤维纱绕包＋耐高温涂覆液浸渍结构的耐高温导线。为使新型耐高温导线能在500℃的高温环境中长期使用，在绝缘绕制时涂覆耐高温材料，这改进了原有高硅氧玻璃纤维纱绕包的传统工艺。采用高硅氧玻璃纤维纱绕包和耐高温涂覆层生产的新型耐高温导线，在电性能和机械性能方面都取得令人满意的效果。     

一种基于BCD工艺的高速低功耗电平位移电路

提出了一种基于0.25 μm BCD工艺、适用于高压降压型DC-DC转换器的新型电平位移电路.该电路使用了耐压60 V的高压DMOS器件(HVNMOS、HVPMOS)、耐压5V的低压CMOS器件(LVNMOS、LVPMOS),以及耐压5V的三极管器件(BJT).分析了降压型DC-DC转换器对电平位移电路的特殊要求;基于对两种常见电平位移电路的分析,提出了一种新型的电平位移电路.电路仿真结果显示,与之前的电路相比,新型电路结构具有响应快速、功耗低、输出电平精确、可靠性高等优点.     

一种新型数字鉴频器在调频接收机的应用

为了解决模拟鉴频器中心频率和鉴频灵敏度随温度变化而发生漂移,以及在批量生产中,模拟鉴频器的生产效率低,产品一致性差等一系列问题,采用基于数字集成电路的设计方法设计了一种新型高性能数字鉴频器。通过多次实验证明,采用这种设计的鉴频器具有鉴频灵敏度高,且不随温度变化而发生显著漂移等优点,极大地提高了生产效率,并保证了产品的一致性。     

基于改善极化相似性的极化SAR目标增强新方法

针对高分辨极化SAR目标增强问题,该文提出一种基于改善极化相似性的目标增强新方法。利用Huynen分解、极化方位角提取及极化方位角归零化处理消除了扰动分量、相干斑噪声及极化取向等因素对像素点极化特性的影响,改善了极化SAR图像同类区域内部像素点的极化相似性。与已有方法相比,该方法克服了区域内部像素点极化特性不一致对高分辨极化SAR目标增强的影响,可以获得理想的目标区域整体增强效果。利用全极化SAR实测数据验证了该文方法的优良性能。     

基于高频谐振变换器的新型微波炉电源设计

文章研究了一种基于高频谐振变换器的新型微波炉电源,详细分析了该新型电源的变换器结构,核心控制芯片以及驱动电路,并对变换器的拓扑结构进行仿真。最后通过实验样机证明,该新型微波炉电源实现了零电压软开关功能,减小了开关损耗,大幅度提高了变换器的工作频率,从而提高了电源的变换效率,具有良好的应用前景。     

High-Efficiency and Low-Stress ZVT–PWM DC-to-DC Converter for Battery Charger

This work presents a novel highly efficient and low-stress battery charger with a resonant switch converter—based on resonance and zero-voltage-transition soft-switching theory—that reduces defects associated with high voltage and high current stresses caused by the resonance of traditional resonant circuits. The novel battery charger meets the requirement that all circuit components must operate with zero-voltage switching. Experimental test results indicate that the proposed battery charger reduces the temperature of an active power switch, and switching losses are less than those obtained using a traditional pulsewidth-modulation converter as a battery charger.      

一种基于串联混合型有源滤波器的仿真新方法

分析了串联混合型有源滤波器(SHAPF)的拓扑结构及其复合检测控制方法,基于瞬时无功功率理论,利用仿真软件MATLAB构建了一种新的三相系统模型。仿真的结果验证该新方法可以有效的对串联混合型有源滤波器的工作情况进行分析和参数设计,具有仿真精度高、速度快的特点。     

PSM开关变换器的大信号模型与瞬态特性

针对传统PWM调制具有轻载下效率低的缺点,论文作者提出一种新的高效调制模式——脉冲跨周调制PSM模式.本文对这种新的PSM开关变换器调制模式进行了包括大信号解析模型、离散模型和相平面模型的大信号建模工作,并借助变换器的解析解、离散模型和相平面分析法对PSM变换器开环/闭环系统的瞬态响应特性进行了分析.研究表明PSM变换器不仅较PWM调制模式轻载下效率高,而且具有响应速度更快,抗干扰性更好的特点.     

一种偏置电流可调节的高效率2.4GHz锗硅功率放大器

基于IBM0.35μm SiGe BiCMOS工艺BiCMOS5PAe实现了一种偏置电流可调节的高效率2.4GHz锗硅功率放大器。该功率放大器采用两级单端结构和一种新型偏置电路,除射频扼流电感外,其它元件均片内集成。采用的新型偏置电路用于调节功率放大器的静态偏置电流,使功率放大器工作在高功率模式状态或低功率模式状态。在3.5V电源条件下,功率放大器在低功率模式下工作时,与工作在高功率模式下相比,其功率附加效率在输出0dBm时提高了56.7%,在输出20dBm时提高了19.2%。芯片的尺寸为1.32mm×1.37mm。     

High power and high sensitivity planar lightwave circuit moduleincorporating a novel passive alignment method

A high-power, high-sensitivity planar lightwave circuit (PLC) module, comprising a laser diode (LD) and a photodiode (PD) surface mounted on a PLC platform, has been realized by a novel passive alignment technique. We used a spot-size transformed LD and a corner-illuminated PD to form a highly efficient optical coupling between the devices and a PLC waveguide. We used the unique marker alignment method to ensure accurate positioning of them. The positioning precision achieved in the lateral direction was within 1 μm for the LD's and within 10 μm for the PD's. The rotational precision was within 0.4° for both chips. We realized high power operation (>8 mW) with a high receiver sensitivity (0.3 A/W). In this paper, we describe a high power, high sensitivity PLC incorporating a novel passive optical alignment technique for LD's and PD's     

一种新型大动态范围CMOS图像传感器

提出了一种具有新型像素结构的大动态范围CMOS图像传感器,通过调整单个像素的积分时间来自适应不同的局部光照情况,从而有效提高动态范围。设计了一种低延时、低功耗、结构简单的新型pixel级电压比较器及基于可逆计数器的时间-电压编码电路。采用0.6μm DPDM标准数字CMOS工艺参数对大动态范围像素单元电路进行仿真,积分电容电压Vcint与光电流呈良好的线性关系,其动态范围可达126dB。在3.3V供电电压下,单个像元功耗为2.1μW。     

基于单电子器件的蔡氏电路实现

基于提出的单电子晶体管和MOS混合器件构成的非线性电阻电路以及CMOS构建的模拟电感,实现了一种新型蔡氏混沌电路,得到其双涡卷混沌吸引子.研究表明,该混沌电路具有结构简单、功耗较低,实现效果好、集成度高等优点,为混沌电路在理论和实践方面提供了新的硬件基础,同时,也为保密通信领域提供了又一种可行的实现方法.     

Helical‐Like 3D Ultrathin Piezoelectric Element for Complicated Ultrasonic Field

The developments of personalized medicine, ultrasound imaging, and contactless “microscopic handle” techniques are pushing ultrasonic transducers toward features of high frequency, device miniaturization, and even novel function. However, the conventional ultrasonic transducer has severely limited the development of novel ideas for applications due to its ordinary ultrasonic field. Although transducer arrays and monolithic acoustic holograms are capable of producing the complicated ultrasonic field, it is still difficult to achieve high frequency, device miniaturization, and novel function simultaneously. Here, a simple but effective approach is introduced that aims at reconstructing the complicated and high‐frequency ultrasonic field via a compact single‐element ultrasonic transducer. The 3D ultrathin piezoelectric element with a complex configuration is demonstrated theoretically and experimentally to produce the desired complicated ultrasonic field. With helical‐like configuration, the single‐element ultrasonic transducer offers efficient noncontact trapping and manipulation of suspended microparticles and biological cells. Moreover, its strong trapping capability leads to the 3D stacking of microparticles, which is a novel and interesting phenomenon achieved by a single‐element ultrasonic transducer. This work brings the possibility of a complicated ultrasonic field for achieving novel high‐frequency ultrasound applications through the design of smart structure ultrathin piezoelectric materials.     

基因表达式编程和K-Means融合的雷达信号分选

为了解决聚类算法需要较多的先验知识,不能自动进行聚类的问题,提出了基因表达式编程和K-Means融合的雷达信号分选算法。从介绍基因表达式编程和K-Means聚类算法的特点出发,针对雷达信号的实际情况,对两种算法进行了优化融合,并通过模拟雷达辐射源数据进行了仿真验证,仿真结果表明该算法在不需要任何雷达辐射源先验知识的情况下即可自动完成聚类分选,具有98.3%的聚类分选精度和较快的收敛速度,其较高的分选精度在电子情报侦察系统上有着广阔的应用前景。     

Nanocrystalline Perovskite Hybrid Photodetectors with High Performance in Almost Every Figure of Merit

Conversion of photon into electron is a phenomenon of great importance in nature. Photodetectors based on this principle have immense potential applications at the frontiers of both scientific and industrial communities, thus affecting the daily life. Herein, a novel class of high‐quality organic–inorganic trihalide perovskite nanoscale hybrid photodetectors is presented based on carbon electrode?molecule junctions working at mild conditions. Almost every figure of merit with high performance, such as highest responsivity, highest photogain, high detectivity, high linear dynamic range, and a broad spectral response, could be achieved simultaneously in a single device under different biases. These significant achievements benefit from rational choices of novel energy loss‐prevented hybrid perovskite nanocrystals as active materials and optimized carbon electrode?molecule junctions as device architectures, which leads to a hybridization mechanism of photodiodes and photoconductors. These investigations demonstrate a useful photodetector platform that might lead to many future photoelectric conversion applications in the practical way.     

新型耐高温FBG传感系统研究

为解决传统的高温传感器不能满足对电解Al槽温等高温环境的实时在线测量问题,提出了基于波长调制的光纤Bragg光栅（FBG）高温传感系统,设计了一种新型封装结构的耐高温FBG传感头,具有体积小、灵敏度高和线性度好等特点;采用了基于InGaAs图像传感器衍射解调技术对光反射波长进行解调,缩短了系统的响应时间,提高了测量精度...     

基于铁电移相器的Ka波段低成本相控阵天线研究

为解决铁电体陶瓷移相器中高相对介电常数材料间的匹配问题,研制了一种可用于Ka波段低成本相控阵天线的新型铁电体陶瓷材料移相器,并用其设计制作了一种一维电扫低成本相控阵天线。结果表明:通过利用三级阻抗匹配技术,所制新型移相器中高相对介电常数材料间的匹配问题得到了有效解决。当外加偏置电压约为11 kV时,该移相器可在损耗小于2.2 dB的情况下实现360°相移。     

基于56F803型DSP的大功率超声波电源的研究

针对大功率超声波电源高精度、高功率输出的特点,对超声波电源控制策略进行了改进.提出一种基于56F803型DSP的频率跟踪与功率调节相结合的周期分段移相控制策略,研究了基于此控制方法的超声波电源.     

Dynamic Virtual Resource Allocation in Virtualized multi-RAT Cellular Networks

The legacy wireless systems are designed to exploit static configuration and deployment, and cannot handle the discrepancies of the spatio-temporal traffic demand. Cloud RAN (C-RAN) is a novel flexible radio technology that utilizes the virtualization concepts and can efficiently address the static deployment of conventional wireless systems. The C-RAN also leverages high radio network flexibility by introducing the network function virtualization approach to wireless networks. This paper presents a novel C-RAN platform that virtualizes and operates with full GSM and LTE systems. The presented platform is solely based on open-source and off the shelf solutions, providing easy implementation, low cost and high scalability. The paper also introduces a novel dynamic resource allocation algorithm that facilitates the C-RAN’s optimal performance in dynamic scenarios. The proposed algorithm is analyzed and validated on the presented C-RAN platform. The results of the performance analysis clearly show the advantages of the proposed dynamic resource allocation algorithm. Moreover, they prove the applicability of the C-RAN platform for variety of different scenarios.