一种快速脉冲充电器的研究

目前蓄电池的快速充电器大多采用脉冲充电方式,充电周期中包括正脉冲充电时间、停止充电时间以及负脉冲放电时间。本文中充电器由反激变换电路和充放电电路构成,反激变换电路提供输出电压,实现电气隔离,充电回路是可控的双向buck／boost电路,可以工作在正脉冲充电和负脉冲放电模式。并且在反激电路后加PFC控制芯片,采用平均电流法控制,从而提高系统的功率因素。     

基于模糊控制的镍氢电池充电器

文中设计了一款智能快速充电器。采用模糊控制原理进行蓄电池的充电控制,确定了模糊控制器的结构和算法,进行了双输入单输出模糊控制器的设计。该充电器以单片机为核心,运用开关电源技术,采用恒流脉冲充电与模糊控制相结合的充电方法,在保证蓄电池循环寿命不受损害的前提下,大大提高了充电速度。     

镍镉电池脉冲充电适配器

脉冲充电法又称往复式充电法,它是对镍镉电池充电一段时间后,使其短时间进行一次大电流放电,接着再充电一段时间后又进行短时间大电流放电,如此循环往复直到电池充满。这种充电法可以消除镍镉电池在充电过程中产生的极化效应,使其能够较快充满,但需要使用专门设计的脉冲充电器。本适配器可以使不具备脉冲充电功能的一般充电器对镍镉电池进行脉冲充电,只要充电器具有足够的容量即可。 如图所示,双基极三极管T1与其周边元件组成弛张振荡器,在R3两端产生宽度约40ms、间隔约1s的脉冲串。改变R2、C1的数值可以改变脉     

DS2770 Li+电池脉冲充电器与线性充电器的性能比较

脉冲充电器具有许多与线性充电器相同的优点,如:简单、廉价、小尺寸、外部元件少等。与线性充电器相比,脉冲充电器还具有一些独特的优势,它的热量主要耗散在墙上适配器、而不是充电器本身,由此,设计中不需要考虑散热问题。当然,它也存在某些缺陷,按照传统的观点,Li+电池脉冲充电器可能导致电池过早地老化,这一结论是以恒流充电过程和脉冲充电过程采用了相同的充电电流为前提的。利用DS2770构成的脉冲充电器进行一系列测试后,所得数据与传统观点并不相符。本文对线性充电器(CC/CV)和DS2770电池监视与脉冲充电器的测试数据进行了比较,主要…     

用于可充电电池的低成本CCR充电方案

电池充电功能的关键考虑因素充电器必须完成基本的电池充电功能,优化充电进度相关的充电速率(因而使每次充电所需时长不会为用户带来不便),进而终止充电过程(因而不损伤电池,不影响其长期工作)。通过应用简单的控制器机制,有可能及时地终止充电过程。充电器类型充电器可以采用恒定直流或脉冲直流功率途径。就各种途径而言,输     

可单体充电的镍氢／镍镉快速充电器

随着各种可携式电子产品的普及化,镍氢、镍镉电池用快速充电器成为生活中的必需品,然而大部分的充电器都无法作单数电池充电,因此接着要介绍可作单数电池充电快速充电器。     

间歇式脉冲三段式充电器的设计

介绍了一种用于电动车高性能铅酸蓄电池的间歇式脉冲三段式充电器的设计方法,该充电器不仅对铅酸蓄电池有良好的充电效果,而且还对电池的充电损耗有修复功能,故可大大提高铅酸蓄电池的使用寿命。     

基于PIC16C73B的电动自行车充电器的设计

随着电动自行车的日益普及,电动自行车充电器的性能有待完善和发展。所研究的充电器为专用36 V电动自行车铅酸蓄电池智能脉冲充电器,他主要由高频开关充电电源和单片机2部分组成。整个充电过程中的5个状态预充电、快充电、补充充电、涓流充电和停充是由单片机PIC16C73B控制而自动实现转换的,并且设置了温度补偿控制,避免了电池出现过充和充电不足现象。     

点击手机充电器

手机充电器的主要类型目前移动电话充电器主要有旅行充电器、座式充电器等。旅行充电器由于其携带方便,对于经常出外旅行的人来说比较合适,它一般是快速充电方式,充电时间为２－３小时。座式充电器一般设计成双槽,让使用者除了给手机上正在用的电池充电外,还可以再充一节电池。所以,座充一次能充两节电池。座式充电器一般是采取涓流充电方式为电池充电,充电时间较旅行充电器长２－３小时,大约为４－５小时。除了上述两种充电器外,另外还有车载充电器,可以方便用户在汽车上为手机充电。车载充电器的一端插入点烟器,另一端连接手机…     

智能手机锂离子电池充电器

<正> 手机作为一种方便的现代化通信工具已逐渐被大量使用,因而手机的配件充电电池和快速充电器的需求量日益增加。目前,锂离子充电电池已逐渐成为手机电池的主流;而市场上大多数手机充电器仍采用IC控制的恒C率快速充电方式,其充电时间虽然满足了用户的要求,但充电效果不佳。 本文介绍一种智能手机充电器,它采用模糊控制技术,令充电器按照最佳的充电曲线对锂离子手机充电电池充电,可获得最佳的充电效果。下面将对锂离子充电电池的结构原理和充电特性、智能充电器的模糊控制方法、电路结构和控制软件作详细介绍。     

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.     

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.     

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.