C频段宽带低杂散频率合成器的设计与实现

在此介绍了小数分频锁相频率合成器的相关理论。设计一个带宽为580 MHz、杂散抑制度≤-60 d Bc、相位噪声≤-85 d Bc/Hz@10 k Hz的C频段宽带低杂散频率合成器。利用双环锁相频率合成技术和小数分频锁相技术,实现了宽带、低杂散的锁相频率合成器的设计。最后经过测试近端杂散指标≤-60 d Bc,远端杂散指标≤-70 d Bc,偏移10 k Hz的相位噪声为-89.95 d Bc/Hz,技术指标都优于设计要求。     

基于MSRCR理论的算法实现

色彩恢复多尺度Retinex算法(MSRCR)是在单尺度Retinex算法(SSR)和多尺度Retinex算法(MSR)的基础上进行的改进和增强,其能明显改进上述2种算法的图像偏色效果并扩大图像的动态范围,使图像的明、暗区域细节都能得到很好的体现.给出一种改进的基于MSRCR理论的算法实现,实验表明,该算法实用性强,在图像对比度和细节增强方面都有很好的效果.     

A High Energy Density Asymmetric Supercapacitor from Nano‐architectured Ni(OH)2/Carbon Nanotube Electrodes

The demand for advanced energy storage devices such as supercapacitors and lithium‐ion batteries has been increasing to meet the application requirements of hybrid vehicles and renewable energy systems. A major limitation of state‐of‐art supercapacitors lies in their relatively low energy density compared with lithium batteries although they have superior power density and cycle life. Here, we report an additive‐free, nano‐architectured nickel hydroxide/carbon nanotube (Ni(OH)₂/CNT) electrode for high energy density supercapacitors prepared by a facile two‐step fabrication method. This Ni(OH)₂/CNT electrode consists of a thick layer of conformable Ni(OH)₂ nano‐flakes on CNT bundles directly grown on Ni foams (NFs) with a very high areal mass loading of 4.85 mg cm^?2 for Ni(OH)₂. Our Ni(OH)₂/CNT/NF electrode demonstrates the highest specific capacitance of 3300 F g^?1 and highest areal capacitance of 16 F cm^?2, to the best of our knowledge. An asymmetric supercapacitor using the Ni(OH)₂/CNT/NF electrode as the anode assembled with an activated carbon (AC) cathode can achieve a high cell voltage of 1.8 V and an energy density up to 50.6 Wh/kg, over 10 times higher than that of traditional electrochemical double‐layer capacitors (EDLCs).     

国外基于电动技术的机械负载模拟的现状

简要叙述了研究电动机械负载模拟系统的必要性,介绍了国外目前在电动机械负载模拟系统方面的一些情况及该系统的一些典型控制策略,并分析了它们的优缺点,最后进行了总结.     

虚拟样机技术在航空发动机设计中的应用

虚拟样机技术的应用为航空发动机设计提供了一种方便、有效的途径.论述将虚拟样机技术应用到航空发动机设计中的意义,通过具体实例探讨虚拟样机技术在某型号无人机发动机设计中的应用.     

机电产品绿色再制造综合评价模型及应用

为有效评估废旧机电产品的可再制造度,支撑废旧机电产品绿色再设计和再制造方案的形成,结合绿色制造技术、质量、经济、资源、环境(TQCRE)五大决策属性,通过对影响废旧机电产品再制造的技术、经济、质量、资源、环境和时间等因素进行分析,建立了废旧机电产品绿色再制造综合评价指标体系及其框架流程.通过定性和定量相结合、模糊综合评价等方法,建立了绿色再制造综合评价模型,并通过一个实例验证该模型的可行性和实用性.     

氟烃基改性硅油的合成及其消泡性能

以丙烯酸(AA)和1H,1H,2H,2H-全氟癸醇(PFD)为原料合成了丙烯酸氟醇酯(AAFDE),用AAFDE与含氢硅油(HPS)硅氢加成得到氟硅油(FPS),确定了合成的较佳工艺条件,同时测定了FPS的表面张力和对柴油体系的消抑泡性能。结果表明,合成AAFDE较佳的工艺条件为:在浓硫酸(SA)催化下,甲苯为溶剂,n(AA)∶n(PFD)∶n(SA)=1.2∶1∶0.3,反应6 h,产率69%。合成FPS较佳的工艺条件为:无溶剂存在条件下,m(AAFDE)∶m(HPS)=1.1∶1,催化剂H2PtC l6的用量为8μg/g(以Pt计),110-120℃反应1 h,产率90%。用红外光谱(IR)对AAFDE和FPS进行了分析。25℃下,FPS的表面张力为21.4 mN/m,明显低于HPS(22.6 mN/m)。在柴油中,通过摇瓶法测得合成的FPS比HPS和烷基硅油(APS)具有更好的消抑泡性能。     

A combined low power SAR capacitance-to-digital analog-to-digital converter for multisensory system

A combined successive approximation (SAR) capacitance-to-digital converter (CDC)/analog-to-digital converter (ADC) for biomedical multisensory system is presented in this paper. The two converters have same circuit blocks and can be exchanged by four switches. Capacitance or voltage from different sensing elements can be measured and converted to digital output directly. This single chip takes place of separated CDC and ADC so that the power consumption of the multisensory system is reduced. The asynchronous SAR circuit has low power and small area. A dynamic comparator with zero-static power is adopted. Switches are carefully designed to reduce the non-idealities of the converter. Several techniques, such as bootstrapped switches, bottom-plate sampling, dummy switches are used to improve the performance of the circuit. The CDC/ADC is fabricated in 0.18 μm CMOS process. Measurement results show that the ENOB of this 11 bits converter is 10.15 bits and its FOM is 45 fJ/conversion-step under 200 kHz sampling. The power consumption is 9.4 μW with 1.4 V power supply voltage and the core area is 0.1764 mm².     

B~+注入隔离在宽禁带半导体中的应用

利用B~+离子注入实现宽禁带半导体的有源层隔离。通过Monte Carlo软件TRIM模拟,优化离子注入能量和剂量。在SiC MESFET中测量两组不同条件的样品及在GaN HEMT测量了三组同种条件的样品都得到了纳安级电流,表现了很好的隔离效果;通过测试表明离子注入隔离的器件相比台面隔离器件的击穿电压有一定程度提高。     

一种点对多点无线数据传输系统的设计

介绍了一种点对多点无线数据传输系统的设计,提出了一种基于时分多址的"随机延时"防通信碰撞协议,并给出了该防碰撞协议和相关CRC编码的软件实现方法。该系统可用于智能交通监管,也可用于其它实时性要求较高、但数据量不大的应用。