压电能量收集接口电路的设计与仿真

为了给无线传感器网络节点提供稳定、高效且长期的能量供给,该文提出了一种基于增强型同步电荷提取电路的压电能量收集接口电路(ESECE)。利用Multisim电路仿真软件对增强型同步电荷提取电路进行仿真,并与标准压电能量收集接口电路(SHE)和同步电荷提取电路(SECE)进行对比分析。实验结果表明,在相同激励条件下,ESECE比SECE的输出功率提高了近30%,最大输出功率达到190μW,同时还保证了输出功率与负载电阻的无关性。     

基于同步电荷提取的压电能量俘获电路设计

利用压电振动能量收集技术具有的力-电耦合效应高,无电磁干扰,机构简单等特点,该文提出了一种对称式自供电同步电荷提取电路(SSP-SECE),使用互补三极管实现同步开关控制,通过导向二极管与检测电容可实现峰值自检测。使用Multisim软件建模仿真测试了电路方案的合理性,实验验证了电路的有效性。实验结果表明,采用优化设计的SSP-SECE接口电路使负载电阻功率比标准能量采集电路高约4.23倍,相对于SECE电路整体提升了23.02%。     

SCEI能量回收接口电路的设计

基于压电效应的能量回收接口电路是能量回收系统的重要组成部分,经典的接口电路有标准接口、同步电荷提取电路(SECE)、并联同步开关电感电路(Parallel-SSHI)、串联同步开关电感电路(Series-SSHI)4种。提出并设计了一种新的接口电路——同步电荷提取和翻转电路(SCEI)接口电路,完成了该接口电路在恒定激振位移情况下回收功率的理论分析和计算,并利用电子仿真软件Multisim对SCEI和4种典型接口电路的回收功率进行了仿真和比较。结果表明,SCEI接口电路性能优越,其回收功率约是SECE电路的1.5倍,且与负载无关。     

DICH压电能量回收接口电路设计

设计了一种新的能量回收接口电路——双中间电容回收(DICH)接口电路,该电路由2个LC振荡电路、一个buck-boost转换器和2个中间电容组成。完成了在恒定激振位移情况下该电路的回收功率的理论分析和计算。利用Multisim仿真软件对标准电路、同步电荷提取(SECE)接口电路、并联-同步开关电感回收(SSHI)、串联-SSHI和DICH接口电路进行了仿真比较,结果表明,双中间电容回收(DICH)接口电路在最优负载时的最大回收功率仅小于并联-SSHI接口电路,约是SECE接口电路的2倍,且具有与SECE接口电路同样的特性,即回收功率与负载无关。     

多悬臂梁压电换能器电路的设计与实现

介绍了一种多悬臂梁压电换能器电路。与标准能量采集电路(SEH)相比,三悬臂梁压电换能器电路的理论最大平均采集功率提高了300%。利用Multisim软件仿真,结果表明,三悬臂梁压电换能器电路的最终输出电压为SEH电路的2.11倍;进一步搭建实际电路,其最终最大输出功率为SEH电路的3.12倍,能量转化与利用效率显著提高。     

溶胶-凝胶法制备铜掺杂氧化锌薄膜的光学特性

设计了一种新的能量回收接口电路——双中间电容回收(DICH)接口电路,该电路由2个LC振荡电路、一个buck boost转换器和2个中间电容组成。完成了在恒定激振位移情况下该电路的回收功率的理论分析和计算。利用Multisim仿真软件对标准电路、同步电荷提取(SECE)接口电路、并联 同步开关电感回收 (SSHI)、串联 SSHI和DICH接口电路进行了仿真比较,结果表明,双中间电容回收(DICH)接口电路在最优负载时的最大回收功率仅小于并联 SSHI接口电路,约是SECE接口电路的2倍,且具有与SECE接口电路同样的特性,即回收功率与负载无关。     

基于SECE振动能量收集模块的设计与实现

飞机飞行过程中存在很多振动能,如果可以高效地对振动能量进行收集给传感器供电具有重大意义。针对悬臂梁式压电收集装置的输出功率不高,且现有的电荷提取电路开关管不易达到精确控制的问题,提出了运用MSP430FE425单片机进行精确采样以及开关控制实现方案。通过单片机检测压电片最大振幅值,并控制同步电荷提取电路(SECE电路)进行电荷提取,解决了SECE电路精确开关控制问题。     

基于同步电荷提取的高效多压电能俘获电路设计

本文提出了一种基于同步电荷提取的高效多压电能俘获电路(High Efficiency Multi-piezoelectric Energy Harvesting Circuit Based on Synchronous Electric Charge Extraction,EM-SECE).所提出的电路利用改进的正负峰值检测结构,减小了压电元件(Piezoelectric Transducer,PZT)达到电压峰值处和开关动作之间的相位差,从而提高了单个压电元件的能量收集效率.并且利用单电感的时分复用,实现基于单电感的多个压电元件振动能俘获.所提出电路具有无整流桥结构,且可以实现自供电的特点.实验结果表明,相同实验条件下,单压电EM-SECE电路的俘获功率为标准能量俘获电路(SEH)最大功率的3.09倍;在仅用一个电感的情况下,双压电EM-SECE电路的俘获功率为两个单压电EM-SECE电路之和的97％.     

一种压电振动能量回收电路

为了提高压电式振动能量回收系统的能量回收能力和解决在负载变化使能量回收效率变差的问题,以悬臂梁式压电振动发电系统为例,提出了一种高效的压电振动能量收集电路设计方案,即并联型双同步开关电感接口电路,可将压电梁转换振动能量得到的电能高效地储存到电容中。实验结果表明,压电梁在频率为38.4Hz、加速度有效值为0.035m/s2振动激励下工作时,给出的并联双同步开关能量回收(P-DSSH)接口电路可释放的瞬时功率达0.25mW,是全桥整流接口电路(SEH)最优功率的5.8倍,是并联同步开关电感(P-SSHI)接口电路可释放的瞬时功率的2.2倍,是LTC3588-1电路可释放的瞬时功率的1.27倍,且其工作不受负载变化的影响。     

基于频率变换的压电俘能器接口电路设计

设计了一种可以减小匹配电感的双同步开关电感电路。建立了仿真模型,仿真结果表明该电路的能量采集的功率最大可达1.9 mW。与一般同步电荷提取电路相比,该电路可以使整体电路体积减小了2/3。将此电路应用于不同形状的压电片的振动能量俘获,发现振动频率和压电片的形状对该电路收集到的能量都有影响,当振动频率为40 Hz时,在矩形压电片上收集到的能量最多。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.