在电路教学中培养学生的电磁学应用能力

电路理论中的许多基本概念和基本规律都源于电磁场原理。本文以电路理论中的若干基本概念和基本定律,包括电流、电压、KCL、KVL和集中参数等,介绍了这些概念和定律的电磁场原理,试图尝试在教学或教材建设中适当加强学生的电磁学应用能力,强化课程之间的内在联系,从而使学生具备坚实的电路理论基础。     

浅谈二极管反向特性的演示教学

二极管具有正向导通,反向截止的特性,即在二极管的阳极接正电压,阴极接负电压,就能使电路导通,反之则截止。在电子理论教学中,我们经常会在电路中用灯泡的亮和灭来演示电路的导通和截止。在二极管反向截止状态,还是会有少量的电流通过,称之为漏电流。当给二极管反向加上大电压时,会使它击穿,那这个电压需多大,是不是跟书上的理论值一致?作为一个中职学生,动手制作电路的电能是培养的关键,所以这节课采用演示教学法,使学生对二极管的方向特性有一个直观的了解。     

“电路理论”课堂教学探讨

本文结合具体实例对电路理论课堂教学过程中的几个重点问题,即电压和电流关联与非关联参考方向、等效的概念及等效变换、受控电源的处理及正弦稳态电路的相量分析等问题做了详细的分析,并总结了便于学生学习和理解的教学思路,为电路理论的教学提供了有益的建议。     

关于Howland电流泵电路的分析与讨论

Howland 电流泵电路是一种适用于接地负载的电压-电流转换电路。本文指出了该电路分析过程可能出现的错误,并给出了三种不同的分析与证明方法。从教学的角度看,这三种方法各有不同的侧重点,对学生已掌握的电路理论知识有不同的要求。上述分析结果可供讲授电路课程和开设电路实验的教师参考。     

预设控制量法求含受控源一端口网络的输入电阻

在电路理论中,除了独立电源外,还引进了“受控源”。受控源的源电压或源电流的值受电路中其它支路或元件上电压或电流的控制,本身不独立地起“激励”作用。在分析具有晶体管元件的电路时,受控源的概念是很有用的,并且经常遇到的是只含有一个受控源和线性电阻的电路模型。 在电路分析中,求不含独立源,仅含线性电阻和一个受控源的一端口网络的输入电阻,是一个比较常见的问题。一般可采用在欲求端口外接电压(电流)源,求端口的响应电流(电压),从而得出输入电阻。本文在这一方法的基础上,介绍一个比较简单而又实用的方法,即预设控量法。     

电子设计实践课程的教学与管理

实践动手能力对电子信息专业的毕业生就业尤为重要。电路设计实践课是提高学生电子制作和设计能力的重要课程。针对社会、学校和学情现状,将教学内容分为从简到难的不同模块,课程进行过程中,教师将分析和设计电路的方法逐步教给学生,让学生逐步学会设计电路的方法。完成项目后及时总结和引申,达到举一反三的效果。通过过程考核在教学整个过程中不断检验学生的学习效果收到了很好的效果。     

对《电路》教材中一习题解答的商榷

本文对邱关源主编《电路》（第三版）教材上册中一习题的答案，作一探讨和商榷。该书上册第58页第2－2题如下：电路如图（困1）所示，其中电阻电压源和电流源场已给定，求（1）求电压U。和电流7。；（2）若电阻尼增大，问对那些元件的电压、电流有影响？影响如何？该书中此题答案为（2）只有电阻民和电流源两端电压增大。笔者认为答案（l）是正确的，答案（2）有问题。答案的概念模糊，因为电路中的电流和电压在确定的参考方向下，均为代数值，那么电压增大是指电压的绝对值还是代数值增大？不明确；其次，当电阻尼增大时，对见和电流源两…     

基于Every Circuit软件创新的电子技术课程教学研究

参加中职技能大赛有利于激发学生学习兴趣、提高学生学习水平,但任何一场中职技能比赛都离不开《电子技术基础》课程的学习、应用。然而《电子技术基础》内容庞杂、概念抽象、电路结构复杂,再加上中职学生的学习基础普遍不扎实、学习自觉性普遍较差,对这门课程的学习愈加困难。文章利用Every Circuit对复杂电路进行仿真,使原本庞杂的内容更加清晰、抽象的概念更易理解、复杂的电路结构更加明了。学生在学习中还能直观的观察到动态电压和电流的动画,更好地激发学生学习的兴趣,调动学生学习的积极性。     

电路品质因数的计算

在电路课程教学中,电路的品质因数Q是一个十分重要的概念,它有助于对电路特性的描述。本文对品质因数的定义、各种定义间的相互关系以及品质因数的计算方法等进行了讨论,并对品质因数的教学给出了教学建议。本文的讨论对电路课程的教学具有一定的参考价值。     

电流模式与电压模式电路探析

电流模式电路在现代电子电路中应用十分广泛.电流模式与电压模式电路的识别和分析是教学难点之所在.本文从阻抗的观点出发,应用比较法分析两种模式电路的本质和工作原理、并给出了两者的区别和联系.这种分析方法可以帮助学生深刻掌握两种电路的特点,对学会应用电路和独立设计电路均有一定的指导作用.     

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.