Y形与Δ形电路等效变换式的简明导出方法

Y 形电路与△形电路等效变换在电路分析中能起到简化电路的作用,但由于变换式比较繁杂,记忆起来有一定的难度,这也给该变换的应用带来很大的不便。故有人曾提出过一些能简便地导出该变换式的方法。本文介绍笔者在教学中试用过的一种能比较快捷、简明地导出该变换式的方法。若附图所示出的 Y 形电路和△形电路等效,则当它们对应端子间有相同的电压时,流入对应端子的电流必须分别相等。在特殊情况下,该等效条件会以较简单的形式出现,这就是所谓的特例。我们正是利用 Y 形和△形电路的两个特例来分别导出两组变换式的,并称之为'开路法'和'短路法'。

A Fully Integrated CMOS Readout Circuit for Particle Detectors

Novel schemes for a charge sensitive amplifier （CSA） and a CR-（RC）, semi-Gaussian shaper in a fully integrated CMOS readout circuit for particle detectors are presented. The CSA is designed with poly-resistors as feedback components to reduce noise. Compared with conventional CSA, the input referred equivalent noise charge（ENC） is simulated to be reduced from 5036e to 2381e with a large detector capacitance of 150pF at the cost of 0.5V output swing loss. The CR-（RC）,semi-Gaussian shaper uses MOS transistors in the triode region in series with poly-resistors to compensate process variation without much linearity reduction.

A Radial Stub Test Circuit for Microwave Power Devices

With the principles of microwave circuits and semiconductor device physics, two microwave power device test circuits combined with a test fixture are designed and simulated, whose properties are evaluated by a parameter network analyzer within the frequency range from 3 to 8GHz. The simulation and experimental results verify that the test circuit with a radial stub is better than that without. As an example, a C-band AlGaN/GaN HEMT microwave power device is tested with the designed circuit and fixture. With a 5.4GHz microwave input signal,the maximum gain is 8.75dB,and the maximum output power is 33.2dBm.

Electro-Discharge Fine Truing of Metal-Bonded Fine-Grain Diamond Wheel Based on Real-Time Monitoring

A data acquisition system based on LabVIEW is designed and implemented, and electro-discharge(ED) fine truing of metal-bonded fine-grain diamond wheel based on real-time monitoring is researched. Real-time monitoring not only makes efficient impulse specification of ED truing easily obtained, but also is good for timely identifying no-load, avoiding short circuit and arc discharge phenomena and then for obtaining normal machining state. ED fine truing of the fine-grain wheel includes two steps: rough truing for high efficiency and fine truing for high precision. Final ED truing precision and efficiency not only depend on electric process specification, but also is concerned with electrode shape, insulated performance of operating fluid and vertical feed quantity value and frequency. Experiments indicate that ED fine truing based on real-time monitoring can improve the truing precision and efficiency. Average machining efficiency of W10 wheel is about 0.95 μm/min; the final run-out by ED truing is less than 2 μm.

Characteristic test of analog integrated circuit frequency

This paper presents an analog circuit built-in-test （BIT） structure based on boundary scan and realizes the BI＇I. It predigests the test process and improves the test precision by taking the rectangular pulse as stimulator and analog switch as auxiliary bridge. The experiment of uA741 shows that the design is feasible. Compared with the traditional test method, it is better regarding reliability and measurability of the analog circuit system.

A novel wide-range precision instrument for measuring three-dimensional surface topography

We developed a measuring instrument that had wide range, high precision, small measuring touch force. The instrument for three-dimensional (3D) surface topography measurement was composed of a high precision displacement sensor based on the Michelson interference principle, a 3D platform based on vertical scanning, a measuring and control circuit, and an industrial control computer. It was a closed loop control system, which changed the traditional moving stylus scanning style into a moving platform scanning style. When the workpiece was measured, the lever of the displacement sensor returned to the balanced position in every sample interval according to the zero offset of the displacement sensor. The non-linear error caused by the rotation of the lever was, therefore, very small even if the measuring range was wide. The instrument can measure the roughness and the profile size of a curved surface.

Visual positioning of rectangular lead components based on Harris corners and Zernike moments

With the increasing necessities for reliable printed circuit board(PCB) product, there has been a considerable demand for high speed and high precision vision positioning system. To locate a rectangular lead component with high accuracy and reliability, a new visual positioning method was introduced. Considering the limitations of Ghosal sub-pixel edge detection algorithm, an improved algorithm was proposed, in which Harris corner features were used to coarsely detect the edge points and Zernike moments were adopted to accurately detect the edge points. Besides, two formulas were developed to determine the edge intersections whose sub-pixel coordinates were calculated with bilinear interpolation and conjugate gradient method. The last experimental results show that the proposed method can detect the deflection and offset, and the detection errors are less than 0.04° and 0.02 pixels.

CFD-DEM simulation of fluid-solid flow of a tapered column separation bed

Research on recycling waste Printed Circuit Boards(PCB) is at the forefront of preventing environmental pollution and finding ways to recycle resources.The Tapered Column Separation Bed(TCSB) is invented aiming at disposing the problem that fine particles of waste printed circuit boards cannot be separated efficiently so as to obtain further insight about the underlying mechanisms and demonstrate the separation feasibility in the tapered column separation bed.In this work,a Computational Fluid Dynamics(CFD) coupled with Discrete Element Method(DEM) model for two-phase flow has been extended to simulate the fluid-solid flow in the tapered column separation bed.Its validity is demonstrated by its successful capturing the key features of particles' flow pattern,velocity,the pressure distribution,the axial position with time and axial force for particles with different densities.Simulation results show that the plastic particles and resin particles become overflow,while copper particles,iron particles and aluminum particles successively become underflow,with a discharge water flow rate of 1 m^3/h,an obliquity of 30°.The simulated results agree reasonably well with the experimental observation.Using this equipment to separate waste PCBs is feasible,theoretically.

Research on Multi Level Dynamic Voltage Compensator based on MMC

The modular multilevel converter （MMC） is a highly modular, easy to expand; the output voltage waveform is good, especially suitable for application in high voltage power system. This article first introduces the circuit topology and principle of MMC, and the main technical characteristics of MMC. And according to the relationship between the drop power voltage and the load power factor, proposed three working modes of the minimum energy compensation strategy. It is shown that MMC has good application prospect in future medium or high- voltage high power applications, especially be one of candidates for HVDC system application.

Power Supply and Programmable Controller for Multishot Pellet Injector

MPI（multishot pellet injector） was imported from Russia about ten years ago. During the year＇s operation in HL-1M, most electrical equipments were repaired. Since the components are non-standard, so it is difficult to maintain. To fueling experiment meet the requirement of in HL-2A. The power supplies of fast valve and a programmable controller for shooting pellets were developed.

Deterritorializing the Nation： Deleuzian Time, Space and Narrative in the Video Art of Lia Lapithi Shukuroglou

The purpose of this paper is to engage with Gilles Deleuze＇s work on time and space in cinema as a theoretical trajectory for exploring the video art of Lia Lapithi Shukuroglou. In Cinema 2： The Time-Image （1989）, Deleuze argues that post-Second World War cinema has been shaped by a historical transformation compelling it to create new signs and images. Centering on the post-war landscape of Cyprus in 1974, the moment of ＂historical transformation＂ in Deleuze is transposed to this national context; examining Lapithi＇s response to the crisis of historical time in its relation to physical spaces. It negotiates a contextualized reading of three videos and argues that they manifest Deleuzian ＂time-images＂. These texts react to the territorialization of real spaces by deterritorializing official national history. Using Martin Jones＇ study, Deleuze, cinema and national identity： Narrative time in national contexts （2006） Lapithi＇s time-images are interpreted as ＂unruly＂ as they resist a linear narrative and destabilize public time. Contrary to Martin Jones＇s view that time-images constitute a temporary deviation from flowing national time, the author argues that Lapithi excavates alternative temporalities in perpetuity; whilst proposing that in the context of Cyprus the deterritorialization of space by time postpones the nation＇s identity.

IC Reporting in Traditional Sectors of Malaysian Public Listed Firms

One of the significant effects of the knowledge economy is the introduction of new business models with resulting creation of intangible resources represented by intellectual assets. In spite of its clear contribution to a firm＇s sustainability of performance, recognition of these intellectual assets in the financial statements do not correspond with their significance as they have to rigid criteria set by conventional accounting standards. This study seeks to assess the level of intellectual capital （IC） resources reported in Malaysian companies in the traditional sectors of the economy and examine their reporting trends in the annual reports of these companies from years 2003 and 2008 Data was collected from companies listed in the main board of Malaysia Stock Exchange （or Bursa Malaysia） and content analysis was applied. Results show that the extent of IC reporting in the annual accounts of listed companies in traditional sectors is slightly above average.

Reducing Numerical Oscillations through Modified Circuits for Inclusion of Frequency Influence in Transmission Line Representation

In this article, a transmission line is represented by a cascade of n circuits using a single phase. It is analyzed what is the reasonable number of n circuits and the number of blocks composed by parallel resistor and inductor in parallel for reduction of numerical oscillations. It is simulated the numerical routine with and without the effectof frequency in the longitudinal parameters. Initially, it is used to state variables and 7t circuits representing the transmission line composing a linear system which is solved by numerical routines based on the trapezoidal rule. The effect of frequency on the line is synthesized by resistors and inductors in parallel and this representation is analyzed in details. It is described as transmission lines and the frequency influence in these lines through the state variables.

Research on the Natural Image Classification and Segmentation Algorithm based on GPU and Neural Network

In this paper, we conduct research on the natural image classification and segmentation algorithm based on GPU and neural network. The application of image segmentation is very broad, almost appeared in all areas related to image processing, and involved in various types. With the fast development of computing technology and integrated circuit technology, the renewal speed of graphics hardware. Our method combines the GPU with network to optimize the traditional image segmentation and classification methods which will be meaningful. In the future, we will focus our attention on the hardware deployment of the GPU to modify the current approach.

Preliminary Research of the Propagation of Annular IREBS in Coaxial Permanent Magnet Halbach Circuit

The magnetic field of coaxial permanent magnet Halbach circuit is calculated first using the finite element method SUPERFISH and the approximate expression of the magnet circuit is obtained.The forces acting on IREB's electron in such magnetic field are analyzed by the use of fluid model and the radial force equation in modified Mathieu function form is drawn then.At last a 2.5-D particle in-cell(PIC)simulation code is used to investigate the physical process of the IREB's propagation.In the PIC simulation,the electron beam current,thickness,magnet field amplitude and the beam's initial incident angle related to the stable propagation are mainly discussed.The conclusion is made that several kilo-amperes intense annular electron beam could propagate stably,meanwhile the focusing form of such magnet geometry provides action mechanism for the interaction between beam electrons and microwave in the ubitron.

Substrate concentration effect on gene expression in genetic circuits with additional positive feedback

In gene regulatory networks, gene regulation loops often occur with multiple positive feedback, multiple negative feedback and coupled positive and negative feedback forms. In above gene regulation loops, auto-activation loops are ubiquitous regulatory motifs. This paper aims to investigate a two-component dual-positive feedback genetic circuit, which consists of a double negative feedback circuit and an additional positive feedback loop(APFL). We study effect of substrate concentration on gene expression in the single and the networked systems with APFLs, respectively. We find that substrate concentration can tune stochastic switch behavior in the signal system and then we explore relationship of substrate concentration with positive feedback strength in aspect of stochastic switch behavior. Furthermore, we also discuss gene expression and stochastic switch behavior in the networked systems with APFLs. Based on analysis in the networked systems, we discover that genes express in some specific cells and do not express in the other cells when the expression achieves its steady state. These results can be used to well explain the character of regionalization in the expression of genes and the phenomenon of gene differentiation.

Hybrid memristor-CMOS neurons for in-situ learning in fully hardware memristive spiking neural networks

Spiking neural network,inspired by the human brain,consisting of spiking neurons and plastic synapses,is a promising solution for highly efficient data processing in neuromorphic computing.Recently,memristor-based neurons and synapses are becoming intriguing candidates to build spiking neural networks in hardware,owing to the close resemblance between their device dynamics and the biological counterparts.However,the functionalities of memristor-based neurons are currently very limited,and a hardware demonstration of fully memristor-based spiking neural networks supporting in-situ learning is very challenging.Here,a hybrid spiking neuron combining a memristor with simple digital circuits is designed and implemented in hardware to enhance neuron functions.The hybrid neuron with memristive dynamics not only realizes the basic leaky integrate-and-fire neuron function but also enables the in-situ tuning of the connected synaptic weights.Finally,a fully hardware spiking neural network with the hybrid neurons and memristive synapses is experimentally demonstrated for the first time,and in-situ Hebbian learning is achieved with this network.This work opens up a way towards the implementation of spiking neurons,supporting in-situ learning for future neuromorphic computing systems.