A new technique for boosting efficiency of silicon solar cells

A new type of photovoltaic system with higher generation power density has been studied in detail. The feature of the system is a V-shaped module (VSM) with two tilted monocrystalline solar cells. Compared to solar cells in a flat orientation, the VSM enhances external quantum efficiency and leads to an increase of 31% in power conversion efficiency. Due to the VSM technique, short-circuit current density was raised from 24.94 to 33.7 mA/cm², but both fill factor and open-circuit voltage were approximately unchanged. For the VSM similar results (about 30% increase) were obtained for solar cells fabricated by using mono-crystalline silicon wafers with only conventional background impurities.     

圆柱阵二维波束图综合方法研究

圆柱阵通常等效成均匀圆阵进行一维波束图综合,深度方向波束固定且旁瓣级较高。多途效应导致接收基阵处声线弯曲入射,阵增益降低。为了修正圆柱阵的阵增益损失以及提高深度方向的抗干扰性能,在凹槽噪声法的基础上讨论了两种圆柱阵的二维波束图综合方法,即整体二维波束图综合方法和分步二维波束图综合方法。计算机仿真结果表明了两种方法的可行性。     

基于YIG单晶薄膜的陷波器设计

针对基于环球耦合谐振的钇铁石榴石(YIG)小球陷波器装配调试工艺复杂、不利于多通道集成的问题,提出了一种采用静磁波技术来实现YIG单晶薄膜陷波器结构与设计方法.该文通过对单晶薄膜陷波器工作原理的分析,静磁反向体波的角频率与波数(ω-k)色散特性与微带激励谐振换能器的静磁波激励特性的数值计算及器件仿真优化,设计了调谐工作...     

罗兰C接收机中窄带干扰的抑制技术

针对目前的罗兰C接收机在抑制窄带干扰方面的缺陷,将基于LMS算法(最小均方准则)的自适应陷波器应用于罗兰C窄带干扰的抑制,通过仿真,将其与固定频率点的陷波器进行了比较,自适应陷波具有较好的抑制窄带干扰能力。     

Cascode Monolithic DC-DC Converter for Reliable Operation at High Input Voltages

A CMOS OTA-C low-pass notch filter for EEG application is described. The pass-band covers four bands of brain wave and provides more than 65 dB attenuation for the 50 Hz power line interference. The OTA works in the weak inversion region and a low transconductance of 3 nA/V is achieved. The low transconductance enables using small capacitors in the OTA-C filter so that the filter is suitable for the multi-channel EEG integrated circuits. The measured results show the good performance of the filter for filtering the noise in acquired EEG signals. Xinbo Qian received the B.Sc. degree from Beijing Institute of Technology, P.R. China, in 1991 and M.Sc. degree from Institute of Physics, Chinese Academy of Sciences, in 1996. From 1996 to 1999, she was a research engineer in the Institute of Acoustics, Chinese Academy of Sciences, worked on the sonar signal receiving and processing systems. Since 1999, she has been pursuing the Ph.D. degree in Electrical and Computer Engineering department, National University of Singapore, with research direction on on-chip readout circuits for microbolometer focal plane arrays. Now she is employed by Department of Mechanical Engineering and Division of Bioengineering, National University of Singapore as a research fellow. Her research interest is low-noise integrated circuits design and bio-medical sensor electronics, including electroencephalography IC, magnetocardiography IC, low-noise amplifier, filter and data converters etc. Yong Ping Xu graduated from Nanjing University, P.R. China in 1977. He received his Ph.D. from University of New South Wales (UNSW) Australia, in 1994. From 1978 to 1987, he was with Qingdao Semiconductor Research Institute, P.R. China, initially as an IC design engineer, and later the deputy R&D manager and the Director. From 1989 to 1992, he was working on silicon diode based infrared detectors towards his Ph.D. at School of Electrical Engineering, UNSW Australia. From 1993 to 1995, he worked on an industry collaboration project with GEC Marconi, Sydney, Australia, at the same university, involved in design of sigma-delta ADCs. He was a lecturer at University of South Australia, Adelaide, Australia from 1996 to 1998. He has been with the Department of Electrical and Computer Engineering, National University of Singapore since June 1998 and is now an Associate Professor. His general research interests are in the areas of mixed-signal and RF integrated circuits, and integrated MEMS and sensing systems. His current focuses are high-speed wideband ADC, UWB front-end circuits and low-power low-voltage integrated circuits for biomedical applications. He is a Senior Member of IEEE. Xiaoping Li received his Ph.D. degree from Department of Mechanical and Manufacturing Engineering, University of New South Wales, Australia in 1991, and joined the National University of Singapore in 1992, where he is currently an Associate Professor with the Department of Mechanical Engineering and Division of Bioengineering. He was a visiting professor of Tokyo Institute of Technology, Japan in 2000, and visiting professor of Georgia Institute of Technology, USA in 2001. He is a member of American Society of Mechanical Engineers (ASME), a senior member of Society of Manufacturing Engineering (SME) and a senior member of North American Manufacturing Research Institute/SME, and is currently the Chairman of SME Singapore Chapter. His current research interests include neurosensors and nanomachining. He is a guest editor of International Journal of Computer Applications in Technology, USA. He is a regular reviewer of the ASME Journal of Manufacturing Engineering, USA, Transactions of NAMRI/SME, USA, Journal of materials processing technology, UK, International Journal of Machine Tools and Manufacture, UK, and IMechE Journal of Engineering Manufacture, UK.     

声表面波陷波器与纵向耦合结构相结合

为了消除声表面波纵向耦合谐振式滤波器高端带外邻近通带处的肩膀,该文提出将纵向耦合谐振式滤波器与声表面波陷波器相结合,用来改善其近阻带抑制。文中给出了理论模拟及实验结果。实验结果与理论模拟基本一致,验证了方案的可行性。     

多杂波背景下用于低速弱目标检测的滤波器优化设计

该文提出了一种用于多杂波背景下的低速弱目标检测的脉间参差滤波器优化设计,该算法采用脉间滑动脉冲的方式进行参差MTI滤波器设计,并利用与梯度结合的遗传算法搜索最优的脉冲重复周期排布组合,使滤波器第一零点尽可能浅,可在有效抑制杂波和同频干扰的同时避免陷入其中的弱目标丢失,同时该滤波器可形成多个凹口以滤去多种杂波,并将盲速推到三倍音速以外。采用梯度遗传算法对脉冲重复周期进行搜索,由于该算法所需初始种群规模小,与标准遗传算法相比复杂度大大降低。仿真结果和性能分析验证了算法的可行性和有效性。     

LD泵浦的绿激光器偏振特性研究

从导致LD泵浦的直腔Nd:YVO4/KTP绿激光器偏振比差的主要原因出发,提出了采用V型谐振腔结构和Ⅰ类临界位相匹配LBO腔内倍频的方案,实验得到了高于2000：1的偏振比。     

一种基于梯度免疫算法的参差MTI滤波器设计

为了解决动目标检测过程中的盲速问题,通常采用参差周期法设计参差滤波器组来达到同时抑制杂波和推远盲速的效果。提出了一种基于梯度免疫算法的参差MTI滤波器优化设计。该算法利用免疫算法搜索最优参差码,有效地避免了传统遗传算法中的早熟问题。针对传统的遗传算法运算量较大的问题,引入了梯度算子缩小初始种群规模,使运算量大大减少。仿真结果验证了算法的可行性和有效性。     

Adaptive notch filter design under multiple identical bandwidths

Digital notch filters are applied to remove or suppress the narrow-band interferences in digital signals, while preserving other components unchanged. Under the condition of the identical notch bandwidths, a novel design method is put forward in this paper to realize the adaptive notch filter with infinite-impulse response (IIR). Firstly, a specially simplified all-pass filter is introduced to construct an IIR non-adaptive notch filter, which serves as the core part in the adaptive one. Secondly, the criterion of least-mean-square (LMS) is applied to design the desired adaptive notch filter (ANF). The designed ANF can track and suppress multiple non-harmonic interference components simultaneously. Finally, the effectiveness and practicability of the proposed design method are verified by a set of experimental results.