电子信息工程 毕业设计 英文翻译
电气自动化专业毕业设计英文翻译
电气自动化专业毕业设计英文翻译1 Computer structure and functionThis section introduces the internal architecture of a computer and describes how instructions are stored and interpreted and explains how the instruction execution cycle is broken down into its various components.At the most basic level, a computer simply executes binary-coded results. For a general-purpose programmable computer, four necessary elements are the memory, central processing unit (CPU, or simply processor), an external processor bus, and an input/output system as indicated in Fig.3-1 A-1.Fig. 3-1A-1 Basic elements of a computerThe memory stores instructions and data.The CPU reads and interprets the instructions, reads the data required by each instruction, executes the action required by the instruction, and stores the results back in memory. One of the actions that is required of the CPU is to read data from or write data to an external device. This is carried out using the input/output system.The external processor bus is a set of electric conductors that carries data, address and control information between the other computer elements.1-1 The memoryThe memory of a computer consists of a set of sequentially numbered locations. Each location is a register in which binary information can be stored. The “number”of a location is called its address. The lowest address is 0. The manufacturer defines a word length for the processor that is an integral number of locations long. In each word the bits can represent either data or instructions. For the Intel 8086/87 and Motorola MC6800 microprocessors, a word is 16 bits long, but each memory locationhas only 8 bits and thus two 8-bit locations must be accessed to obtain each data word. In order to use the contents of memory, the processor must fetch the contents of the right location. To carry out a fetch, the processor places (enables) the binary-coded address of the desired location onto the address lines of the external processor bus. The memory then allows the contents of the addressed memory location to be read by the processor. The process of fetching the contents of a memory location does not alter the contents of that location.Instructions in memory Instructions stored in memory are fetched by the CPU and unless program branches occur, they are executed in the sequence they appear in memory. An instruction written as a binary pattern is called a machine-language instruction. One way to achieve meaningful patterns is to divide up the bits into fields as indicated in Fig. 3-1A-2, with each field containing a code for a different type of information.0001 0101 1000 XXXX 0100 0001 1000 XXXX 0011 XXXX XXXX 0100 Fields Opcode Immediate code Operand data Branch addressSet ‘5’ in location 8 Subtract ‘1’ f rom location 8 If zero, bran ch to location 416-bit instruction words... ... XXXX : not u sed (or “don ’t care”)Fig. 3-1A-2 Arrangement of program and data in memoryEach instruction in our simple computer can be divided up into four fields of 4 bits each. Each instruction can contain operation code (or opcode, each instruction has a unique opcode), operand address, immediate operands, branch address.In a real instruction set there are many more instructions. There is also a much large number of memory locations in which to store instructions and data. In order to increase the number of memory locations, the address fields and hence theinstructions must be longer than 16 bits if we use the same approach. There are a number of ways to increase the addressing range of the microprocessor without increasing the instruction length: variable instruction field, multiword instructions, multiple addressing modes, variable instruction length. We will not discuss them in detail.Data in memory data is information that is represented in memory as a code. For efficient use of the memory space and processing time, most computers provide the capability of manipulating data of different lengths and representations in memory. The various different representations recognized by the processor are called its data types. The data types normally used are: bit, binary-coded decimal digit (4-bit nibble, BCD), byte (8 bits), word (2 bytes), double word (4 bytes).Some processors provide instructions that manipulate other data types such as single-precision floating-point data types (32bits) and double-precision floating-point data types (64 bits). There is another type of data—character data. It is also usually represented in 8 bits. Each computer terminal key and key combination (such as shift and control functions) on a standard terminal keyboard has a 7-bits code defined by the American Standard Code for Information Interchange (ASCII).Type of memory In the applications of digital control system, we also concerned with the characteristics of different memory techniques. For primary memory, we need it to be stored information temporarily and to be written and got information from successive or from widely different locations. This type memory is called random-access memory (RAM). In some case we do not want the information in memory to be lost. So we are willing to use special techniques to write into memory. If writing is accomplished only once by physically changing connections, the memory is called a read-only memory (ROM). If the interconnection pattern can be programmed to be set, the memory is called a programmable read-only memory (PROM). If rewriting can be accomplished when it is necessary, we have an erasable programmable read-only memory (EPROM). An electronically erasable PROM is abbreviated EEPROM.1-2 The CPUThe CPU’s job is to fetch instructions from memory and execute these instructions. The structure of the CPU is shown in Fig. 3-1A-3. It has four main components: an arithmetic and logical unit (ALU), a set of registers, an internal processor bus and controller.Fig.3-1A-3 Central processing unit (CPU)These and other components of the CPU and their participation in the instruction cycle are described in the following sections.Arithmetic and Logical Unit (ALU) The ALU provides a wide arithmetic operations, including add, subtract, multiply, and divide. It can also perform Boolean logic operations such as AND, OR, and COMPLEMENT on binary data. Other operations, such as word compares, are also available. The majority of computer tasks involve the ALU, but a great amount of data movement is required in order to make use of the ALU instructions.Registers A set of registers inside the CPU in used to store information.Instruction register When an instruction is fetched, it is copied into the instruction register, where it is decoded. Decoding means that the operation code is examined and used to determine the steps of the execution sequence.Programmer’s model of the CPU The collection of registers that can be examined or modified by a programmer is called the programmer’s model of the CPU.The only registers that can be manipulated by the instruction set, or are visibly affected by hardware inputs or the results of operations upon data, are the registers represented in the model.Flag register The execution sequence is determined not only by the instruction but also by the results of the previous instructions. For example, if an addition is carried out in the ALU, data on the result of the addition (whether the result is positive, negative, or zero, for example) is stored in what is known as a flag register, status register, or condition register. If the next instruction is a conditional branch instruction, the flag word is tested in that instruction to determine if a branch if a branch is required.Program counter (instruction pointer)The address of the next instruction is located in a register called the program counter.Data registers When an instruction uses the registers to store data, the reference to the register in the instruction is called register addressing. The reasons of making use of the internal registers to store data are that they can make the instructions shorter and make execution faster.Address registers The internal registers can also be used for the storage of address of data in memory data. In such a case, the instruction word contains a register number (i.e. a register address). In the register is contained the address of memory data to be used in the instruction. This form of addressing is called register indirect addressing. The contents of the register are said to point to the data in memory.Internal Processor Bus The internal processor bus moves data between internal register. A bus is a set of closely grouped electric conductors that transfers data, address, and control information between functional blocks of the CPU. Data from a source register can be passed to a destination register when both are enabled onto (connected to) the bus.Controller The controller provides the proper sequence of control signals for each instruction in a program cycle to be fetched from memory. A total program cycle comprises many instruction cycle, each instruction cycle can be divided up into itscomponent machine cycles and each machine cycle comprises a number of clock cycle.In order to fetch an instruction, for example illustrated in Fig.3-1A-4, the address in the program counter is placed on the address lines of the external bus (AB) at the onset of clock cycle C1. Simultaneously, using a code on the control lines of the bus (CB), the CPU informs all devices attached to the bus that an “opcode” fetch machine cycle is being executed by the CPU. The memory allows the memory address to select the memory location containing the instruction. At C2 the controller places a “read”command onto the control bus which allows the memory data to be placed onto the data bus. The controller then gates the data into the instruction register and removes the read command from the control bus in C3. At C4, the controller removes the address from the address bus and begins to decode the operation-code portion of the instruction to see what steps are required for execution. The decoding operation may take several more clock cycle at the end of which the “opcode fetch” machine cycle.Fig. 3-1A-4 A timing diagram for "operation-code fetch "External attention requests It is often necessary to stop the normal instruction processing sequence. One type of external attention request is the reset request. In thecase of an unrecoverable error, a computer system may be required to reset itself .This would have the effect of initializing all important registers in the system and starting instruction execution from a standard memory location-usually location 0.An input that is more commonly activated during the normal course of events is the interrupt request. An interrupt request signal from an external device can cause the CPU to immediately execute a service subroutine which carries out the necessary actions. After completing the service subroutine, the processor will continue the task from which it was originally interrupted.The third type of input is the bus request, or direct memory access(DMA) request. It is possible to have a terminal interface that stores up all the characters in a line of text until it receives a "carriage return." Then the interface requests the use of the system bus, at which time the complete line of data is transferred to memory as fast as possible. In this way the processor simply becomes inactive until the transfer is completed.1-3 BusesThe bus is the most important communication system in a computer system. Under control of the CPU, a data source device and a data destination device are "enabled" onto(equivalent to being connected to) the bus wires for a short transmission.External processor bus The internal processor bus described in Sec. is connected to the external processor bus by a set of bus buffers located on the microprocessor integrated circuit.System bus The microcomputer board can communicate with other boards by connecting its bus to an external system bus through a connector.1-4Computer Input and OutputA set of registers external to the CPU is associated with what is known as the input/output (I/O) system. The I/O system is connected to the external processor bus using control, address, and data buses through an I/O registers in an interface. There are basically two ways that are used to address I/O register.In the first method, called I/O-mapped input/output, the operation code itself hasspecial I/O instructions that address a numbered register in the interface called an I/O port.The second method of addressing I/O registers gives the I/O ports addresses that lie within the memory address range of the CPU. This is called memory-mapped I/O. Of course there must not be any memory locations at the same address as I/O locations.One of the benefits of the memory-mapped approach is that the full range of memory addressing modes is available to the addressing of I/O registers.2Fundamentals of Computer and Networks2-1 Organization of Computer SystemA computer is a fast and accurate symbol manipulating system that is organized to accept, store, and process data and produce output results under the direction of a stored program of instructions. This section explains why a computer is a system and how a computer system is organized. Key elements in a computer system include input, processing, and output devices. Let's examine each component of the system in more detail.Input Devices Computer system use many devices for input purpose. Some INPUT DEVICES allow direct human/machine communication, while some first require data to be recorded on an input medium such as a magnetizable material. Devices that read data magnetically recorded on specially coated plastic tapes or flexible or floppy plastic disks are popular. The keyboard of a workstation connected directly to (or ONLINE to) a computer is an example of a direct input device. Additional direct input devices include the mouse, input pen, touch screen, and microphone. Regardless of the type of device used, all are components for interpretation and communication between people and computer systems.Central Processing Unit The heart of any computer system is the central processing unit (CPU). There are three main sections found in the CPU of a typical personal computer system: the primary storage section, the arithmetic-logic section,and the control section. But these three sections aren't unique to personal computers. They are found in CPUs of all sizes.Output Device Like input units, output device are instruments of interpretation and communication between humans and computer system of all size. These device take output results from the CPU in machine-coded form and convert them into a form that can be used (a) by people (e.g. a printed and /or displayed report) or (b) as machine input in another processing cycle.In personal computer systems, display screen and desktop printers are popular output devices. Larger and faster printers, many on-line workstations, and magnetic tape drives commonly found in large systems.The input/output and secondary storage units are sometimes called peripheral devices (or just peripherals). This terminology refers to the fact that although these devices are not a part of the CPU, they are often located near it. Besides, a computer system also includes buses, ROM(read only memory), RAM(random access memory), parallel port and serial port, hard disk, floppies and CD(compact disk)drive, and so on.2-2 Operating SystemOperating systems have developed over the past thirty years for two main purposes. First, they provide a convenient environment for the development and execution of programs. Second, operating systems attempt to schedule computational activities to ensure good performance of the computing system.The operating system must ensure correct operation of the computer system. To prevent user programs form interfering with the proper operation of the system, the hardware was modified to create two modes: user mode and monitor mode. Various instructions (such as I/O instructions and halt instructions) are privileged and can only be executed in monitor mode. The memory in which the monitor resides must also be protected from modification by the user. A timer prevents infinite loops. Once these changes (dual mode, privileged instructions, memory protection, timer interrupt) have been made to the basic computer architecture, it is possible to write a correct operating system.As we have stated, operating systems are normally unique to their manufacturers and the hardware in which they are run. Generally, when a new computer system is installed, operational software suitable to that hardware is purchased. Users want reliable operational software that can effectively support their processing activities.Though operational software varies between manufacturers, it has similar characteristics. Modern hardware, because of its sophistication, requires that operating systems meet certain specific standards. For example, considering the present state of the field, an operating system must support some form of on-line processing. Functions normally associated with operational software are:1)Job management;2)Resource management;3)Control of I/O operations4)Error recovery;5)Memory management.2-3 NetworksCommunication between distributed communities of computers is required for many reasons. At a national level, for example, computers located in different parts of the country use public communication services to exchange electronic messages (mail) and to transfer files of information from one computer to another. Similarly, at a local level within, say, a single building, distributed communities of computer-based workstations use local communication networks to access expensive shared resources—for example, printers and disks tapes and copiers, etc.—that are also managed by computers. Clearly, as the range of computer-based products and associated public and local communication networks proliferate, computer-to-computer communication will expand rapidly and ultimately dominate the field of distributed systems.Although the physical separation of the communicating computers may vary considerably from one type of application to another, or, at the heart of any computer communication network is the data communication facility which, may be a PSDN, aprivate LAN or perhaps a number of such networks interconnected together. However, irrespective of the type of data communication facility, an amount of hardware and software is required within each attached computer to handle the appropriate network-dependent protocols. Typically, these are concerned with the establishment of a communication channel access the network and with the control of the flow of messages across this channel. The provision of such facilities is only part of the network requirements, however, since in many applications the communicating computers may be of different forms of data representation interface between user (application) programs, normally referred to as application processes or APs, and the underlying communication services may be different. For example, one computer may be a small single-user computer, while another may be a large multi-user system.3 Stepper motorStepper motor is the electric pulse signals into angular displacement or linear displacement of the open-loop stepper motor control element pieces. In the case of non-overloaded, the motor speed, stop position depends only on the pulse frequency and pulse number, regardless of load changes, when the driver receives a step pulse signal, it will drive a stepper motor to Set the direction of rotation of a fixed angle, called the "step angle", which the angle of rotation is fixed step by step operation. Number of pulses can be controlled by controlling the angular displacement, so as to achieve accurate positioning purposes; the same time by controlling the pulse frequency to control the motor rotation speed and acceleration, to achieve speed control purposes.3-1 WorkInduction motor is a stepper motor, does it work is the use of electronic circuits, the DC power supply into a time-sharing, multi-phase timing control current, this current stepper motor power supply, the stepper motor to work properly , The drive is sharing power supply for the stepper motor, the polyphase timing controller.Although the stepper motor has been widely used, but the stepper motor does notlike a normal DC motor, AC motor in the conventional use. It must be double-ring pulse signal; power driver circuit composed of the control system can be used. Therefore, it is not easy with a good stepping motor, which involves mechanical, electrical, electronics and computers, and much other specialized knowledge.As the stepper motor actuators, electromechanical integration, one of the key products, widely used in a variety of automatic control systems. With the development of microelectronics and computer technology, increasing demand for stepper motor has applications in all areas of the national economy.3-2 CategoriesNow more commonly used include the reaction of step motor stepper motor (VR), permanent magnet stepper motor (PM), hybrid stepper motors (HB) and single-phase stepper motor.3-3 Permanent magnet stepper motorPermanent magnet stepper motor is generally two-phase, torque, and smaller, usually 7.5 degree step angle or 15 degrees;Permanent magnet stepper motor output torque, dynamic performance, but a large step angle.3-4 Reaction Stepper MotorReaction is generally three-phase stepping motor can achieve high torque output, step angle of 1.5 degrees is generally, but the noise and vibration are large. Reaction by the stepper motor rotor magnetic circuit made of soft magnetic materials, a number of the stator phase excitation winding, the use of permeability changes in torque.Step Motor simple structure, low production costs, step angle is small; but the dynamic performance is poor.3-5 Hybrid Stepping MotorHybrid Step Motor combines reactive, permanent magnet stepper motors of both, it's a small step angle, contribute a large, dynamic performance, is currently the highest performance stepper motor. It is also sometimes referred to as PermanentMagnet Induction Stepping Motor. It consists of two phases and the five-phase: the general two-phase step angle of 1.8 degrees and the general five-phase step angle 0.72 degrees. The most widely used Stepper Motor. Stepper motor drive for energy saving 3-6 Three-phase stepper motor drive special features:◆180% low torque output, low frequency characteristics of a good run◆Maximum output frequency 600Hz, high-speed motor control◆full range of detection of protection (over voltage, under voltage, overload)instantaneous power failure restart◆acceleration, deceleration, such as dynamic change in the stall protection functionto prevent◆Electrical dynamic parameters of automatic recognition function to ensurestability and accuracy of the system◆quick response and high-speed shutdown◆abundant and flexible input and output interface and control, versatility◆use of SMT production and three full-mount anti-paint treatment process, productstability and high◆full range of Siemens IGBT power devices using the latest, to ensure the qualityof high-quality3-7 Basic principlesUsually for the permanent magnet rotor motor, when current flows through the stator windings, the stator windings produce a magnetic field vector. The magnetic field will lead to a rotor angle of the magnetic field makes the direction of a rotor and the stator's magnetic field direction. When the stator magnetic field vector rotating at an angle. As the rotor magnetic field is also transferred from another perspective. An electrical pulse for each input, the motor turning a point forward. It is the angular displacement of the output and input the number of pulses proportional to speed and pulse frequency is proportional to. Power to change the order of winding, the motor will reverse. Therefore, the number of available control pulse, frequency and power the motor windings of each phase in order to control the stepper motor rotation.3-8 Induction Stepping Motor3-8-1 features: Induction, compared with the traditional reactive, structural reinforced with a permanent magnet rotor, in order to provide the working point of soft magnetic materials, and the stator excitation magnetic field changes only need to provide to provide the operating point of the consumption of magnetic materials energy, so the motor efficiency, current, low heat. Due to the presence of permanent magnets, the motor has a strong EMF, the damping effect of its own good, it is relatively stable during operation, low noise, low frequency vibration. Induction can be seen as somewhat low-speed synchronous motor. A four-phase motor can be used for four-phase operation, but also can be used for two-phase operation. (Must be bipolar voltage drive), while the motor is not so reactive. For example: four phase, eight-phase operation (A-AB-B-BC-C-CD-D-DA-A) can use two-phase eight-shot run. Not difficult to find the conditions for C =, D =. a two-phase motor's internal winding consistent with the four-phase motors, small power motors are generally directly connected to the second phase, the power of larger motor, in order to facilitate the use and flexible to change the dynamic characteristics of the motor, its external connections often lead to eight (four-phase), so that when used either as a four-phase motors used, can be used for two-phase motor winding in series or parallel.3-8-2 classification：Induction motors can be divided in phases: two-phase motor, three phase motor, four-phase motor, five-phase motor. The frame size (motor diameter) can be divided into: 42BYG (BYG the Induction Stepping motor code), 57BYG, 86BYG, 110BYG, (international standard), and like 70BYG, 90BYG, 130BYG and so are the national standards.3-8-3 the stepper motor phase number of static indicators of terms: very differently on the N, S the number of magnetic field excitation coil. Common m said. Beat number: complete the necessary cyclical changes in a magnetic field pulses or conducting state with n said, or that turned a pitch angle of the motor pulses needed to four-phase motor, for example, a four-phase four-shot operation mode that AB -BC-CD-DA-AB, shot eight four-phase operation mode that A-AB-B-BC-C-CD-D-DA-A. Step angle: corresponds to a pulse signal, the angulardisplacement of the rotor turne d with θ said. θ = 360 degrees (the rotor teeth number of J * run shot), the conventional two, four-phase, the rotor teeth 50 tooth motor as an example. Four step run-time step angle θ = 360 ° / (50 * 4) = 1.8 degrees (commonly called the whole step), eight-shot running step angle θ = 360 ° / (50 * 8) = 0.9 degrees (commonly known as half step.) Location torque: the motor is not energized in the state, its locked rotor torque (as well as by the magnetic field profile of harmonics caused by mechanical error) static torque: the motor under the rated static electricity, the motor without rotation, the motor shaft locking torque. The motor torque is a measure of volume (geometry) standards, and drive voltage and drive power, etc. has nothing to do. Although the static torque is proportional to the electromagnetic magnetizing ampere turns, and fixed air gap between the rotor teeth on, but over-use of reduced air gap, increase the excitation ampere-turns to increase the static torque is not desirable, this will cause the motor heating and mechanical noise.3-9 Characteristics of the stepper motor1. The general accuracy of the stepper motor step angle of 3-5%, and not cumulative.2. Appearance of the stepper motor to allow the maximum temperature.Stepper motor causes the motor temperature is too high the first magnetic demagnetization, resulting in loss of torque down even further, so the motor surface temperature should be the maximum allowed depending on the motor demagnetization of magnetic material points; Generally speaking, the magnetic demagnetization points are above 130 degrees Celsius, and some even as high as 200 degrees Celsius, so the stepper motor surface temperature of 80-90 degrees Celsius is normal.3. Stepper motor torque will decrease with the increase of speed.When the stepper motor rotates, the motor winding inductance of each phase will form a reverse electromotive force; the higher the frequency the greater the back emf. In its role, the motor with frequency (or speed) increases with the phase current decreases, resulting in decreased torque.4. Low-speed stepper motor can operate normally, but if not higher than a certain speed to start, accompanied by howling.。
常用课程的英文翻译
文献检索 document．tion Retrieval
数据库概论 Introduction to Database
网络原理 Principles of Network
人工智能 Artificial Intelligence
Finance 财政学
Financial Accounting 财务会计
Fine Arts 美术
Functions of a Complex Variable 单复变函数
Functions of Complex Variables 复变函数
Functions of Complex Variables & Integral Transformations 复变函数与积分变
数字电子技术 Digital Electrical Technique
电磁场 Electromagnetic Field
微机原理 Principle of Microcomputer
企业管理 Business Management
专业英语 Specialized English
可编程序控制技术 Controlling Technique for Programming
Advanced Mathematics 高等数学
Advanced Numerical Analysis 高等数值分析
Algorithmic Language 算法语言
Analogical Electronics 模拟电子电路
Artificial Intelligence Programming 人工智能程序设计
电子信息工程专业课程翻译中英文对照表
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毕业设计中英文翻译
本科生毕业设计（论文）外文翻译毕业设计（论文）题目：电力系统检测与计算外文题目：The development of the single chipmicrocomputer译文题目：单片机技术的发展与应用学生姓名： XXX专业： XXX指导教师姓名： XXX评阅日期：单片机技术的发展与应用从无线电世界到单片机世界现代计算机技术的产业革命，将世界经济从资本经济带入到知识经济时代。
在电子世界领域，从 20 世纪中的无线电时代也进入到 21 世纪以计算机技术为中心的智能化现代电子系统时代。
现代电子系统的基本核心是嵌入式计算机系统(简称嵌入式系统)，而单片机是最典型、最广泛、最普及的嵌入式系统。
一、无线电世界造就了几代英才。
在 20 世纪五六十年代，最具代表的先进的电子技术就是无线电技术，包括无线电广播，收音，无线通信(电报)，业余无线电台，无线电定位，导航等遥测、遥控、遥信技术。
早期就是这些电子技术带领着许多青少年步入了奇妙的电子世界，无线电技术展示了当时科技生活美妙的前景。
电子科学开始形成了一门新兴学科。
无线电电子学，无线通信开始了电子世界的历程。
无线电技术不仅成为了当时先进科学技术的代表，而且从普及到专业的科学领域，吸引了广大青少年，并使他们从中找到了无穷的乐趣。
从床头的矿石收音机到超外差收音机；从无线电发报到业余无线电台；从电话，电铃到无线电操纵模型。
无线电技术成为当时青少年科普、科技教育最普及，最广泛的内容。
至今，许多老一辈的工程师、专家、教授当年都是无线电爱好者。
无线电技术的无穷乐趣，无线电技术的全面训练，从电子学基本原理，电子元器件基础到无线电遥控、遥测、遥信电子系统制作，培养出了几代科技英才。
二、从无线电时代到电子技术普及时代。
早期的无线电技术推动了电子技术的发展，其中最主要的是真空管电子技术向半导体电子技术的发展。
半导体电子技术使有源器件实现了微小型化和低成本，使无线电技术有了更大普及和创新，并大大地开阔了许多非无线电的控制领域。
论文中英文翻译(译文)
编号：桂林电子科技大学信息科技学院毕业设计(论文)外文翻译（译文）系别：电子工程系专业：电子信息工程学生姓名：韦骏学号：0852100329指导教师单位：桂林电子科技大学信息科技学院姓名：梁勇职称：讲师2012 年6 月5 日设计与实现基于Modbus 协议的嵌入式Linux 系统摘要：随着嵌入式计算机技术的飞速发展，新一代工业自动化数据采集和监测系统，采用核心的高性能嵌入式微处理器的，该系统很好地适应应用程序。
它符合消费等的严格要求的功能，如可靠性，成本，尺寸和功耗等。
在工业自动化应用系统，Modbus 通信协议的工业标准，广泛应用于大规模的工业设备系统，包括DCS，可编程控制器，RTU 及智能仪表等。
为了达到嵌入式数据监测的工业自动化应用软件的需求，本文设计了嵌入式数据采集监测平台下基于Modbus 协议的Linux 环境采集系统。
串行端口的Modbus 协议是实现主/从式，其中包括两种通信模式：ASCII 和RTU。
因此，各种药膏协议的设备能够满足串行的Modbus通信。
在Modbus 协议的嵌入式平台实现稳定和可靠。
它在嵌入式数据监测自动化应用系统的新收购的前景良好。
关键词：嵌入式系统，嵌入式Linux，Modbus 协议，数据采集，监测和控制。
1、绪论Modbus 是一种通讯协议，是一种由莫迪康公司推广。
它广泛应用于工业自动化，已成为实际的工业标准。
该控制装置或不同厂家的测量仪器可以链接到一个行业监控网络使用Modbus 协议。
Modbus 通信协议可以作为大量的工业设备的通讯标准，包括PLC，DCS 系统，RTU 的，聪明的智能仪表。
随着嵌入式计算机技术的飞速发展，嵌入式数据采集监测系统，使用了高性能的嵌入式微处理器为核心，是一个重要的发展方向。
在环境鉴于嵌入式Linux 的嵌入式工业自动化应用的数据，一个Modbus 主协议下的采集监测系统的设计和实现了这个文件。
因此，通信设备，各种药膏协议能够满足串行的Modbus。
电子信息工程毕业设计外文翻译
xx大学毕业设计外文翻译系别职业技术教育学院专业电子信息工程班级电子Z091 学号 x姓名 x指导教师 x2013年5月16日MM420 inverter energy-saving measures in the water supply system-Nanjing Hangda Yihang Technology Co., Ltd.Because the frequency conversion velocity modulation does not need to construct the tradition for the aqueous system for the aqueous system top digit water tank, the water tank, avoided two times polluting and reducing the construction investment, moreover designed reasonably can achieve the good energy conservation effect.In gives in the aqueous system, the constant speed pump only then in its highly effective section movement can guarantee the system normal work also does not have the energy dissipation.In the design, (this time current capacity is generally biggest by the pipe network most unfavorable situation, must lift is also biggest) takes the choice water pump unit the main basis, but when the pipe network current capacity reduces, the energy waste is inevitable, when also possibly creates the low current capacity in pipeline overpressure question.The water pump basis system current capacity real-time change realization stepless speed regulation movement, is solves above problem well, achieves one of energy conservation goal ways.The water pump velocity modulation may through the very many way realization, in which frequency conversion velocity modulation be the present ideal one kind.The frequency conversion velocity modulation is through will give on the aqueous system pipe network the pressure transmitter to carry on the sampling to the pipe network hydraulic pressure, transforms the pressure signal into the electrical signal, and delivers to the PID regulator and the user establishment value of pressure it carries on the comparison and the operation, finally will transform for the frequency control signal delivers to the frequency changer.The frequency changer basis transmits frequency control signal adjustment water pump electrical machinery supply frequency, thus realizes adjusts the water pump the rotational speed.May divide into two kinds according to the customer in actual use request frequency conversion velocity modulation for the aqueous system: The live pressure variable gives the aqueous system for the aqueous system and the constant pressure variable.The live pressure variable establishes for the aqueous system pressure transmitter in the service pipe net terminal, the PID regulator setting value the service flood peakvalue which needs for the pipe network terminal user.The system causes the pipe network terminal hydraulic pressure maintenance through the automatic control to be constant, causes the pipeline characteristic curve and system static lifting is invariable, but the water pump water outlet pressure changes along with the volume of diversion change according to the pipeline characteristic curve, therefore theoretically realized “the system to need how many, the unit provided how many”, could not because the volume of diversion reduced has unnecessary static lifting, the energy conservation effect was satisfied.But this is only one kind of ideal situation, also in the system only has the frequency conversion pump alone to work.Because the frequency conversion equipment quite is expensive, large-scale often uses the frequency conversion pump and the constant speed pump parallel operation way water supply for the aqueous system.Presently establishes a frequency conversion pump and a power frequency pump and the combined transport behavior example by the system in.When the pipe network current capacity reduces, needs to lift reduces correspondingly, the frequency conversion pump may through the deceleration movement realization.But also must reduce correspondingly for guarantee parallel unit normal work power frequency pump lifting, this only can through increase the current capacity realization, thus creates the water volume the dropout, also possibly causes the power frequency pump to leave the highly effective section work, namely has not achieved the true energy conservation the goal.Meets has above situation, may take following measure to improve its energy conservation effect:①Gives the aqueous system regarding the small scale, may only suppose a frequency conversion pump, and causes the pump the highly effective area (its highly effective scope to move the time scope compared to power frequency pump to want as far as possible many including to appear the probability big operating point in a big way).②Uses the multi-Taiwan pump velocity modulation movement, certainly, quite is expensive as a result of the frequency conversion speeder price, should overall evaluation its economic agent decide.③When choice power frequency pump, should cause the system when the most disadvantageous spot work, the power frequency pump operating point approaches left side of as far as possible its highly effective area; If the most unfavorable situation appears the probability to be small, may enable it to deviate slightly the highlyeffective area, falls in the highly effective area left flank.Thus, when system lifting reduces, the power frequency pump still may in the highly effective area work.The constant pressure variable is located in the water pump unit water outlet for the aqueous system the pressure transmitter, is for the purpose of causing the water pump water outlet pressure maintenance to be constant, general hypothesis for most disadvantageous operating mode when the water pump water outlet needs the value of pressure.Still by a frequency conversion pump and a power frequency pump and combined transport behavior example.When the pipe network current capacity reduces, the frequency conversion pump through the deceleration movement, maintenance lifting invariable reduces the water discharge.Because the outlet pressure is invariable, the power frequency pumps out the water volume not to be able to change (i.e. movement operating mode invariably), still in highly effective area work, thus achieves the energy conservation goal.Needs to point out, the system needs when the current capacity changes small, the water pump water outlet pressure (still for the most unfavorable situation in system needs pressure) to be bigger than the pressure which the pipeline this time needs, thus still could cause static lifting to a certain extent the waste.Following two measures may improve its energy conservation effect:①Enlarges the pipe network suitably the caliber, causes the pipeline characteristic curve to hasten gently, but this can increase the pipe network the disposable investment, needs and the energy conservation effect makes the comprehensive economical comparison.②When choice power frequency pump causes each pump the operating point to fall as far as possible on the highly effective area.For aqueous system when water used trough (for example at night), in the system the water consumption is very small, even achieved the zero current capacity, is called “the micro current capacity”.In this case, if depends upon at the highly effective area great current capacity scope movement water pump maintains the system pressure, not only buckle water pump life, moreover the efficiency is low, cannot achieve the energy conservation the goal.Theoretically, the frequency conversion pump current capacity may approach in the highly effective scope in the zero, but in fact the water pump rotational speed not impossible unlimited to reduce, only depends on the frequency conversion pump to be competent the micro current capacity operating mode with difficulty toward the dealings.The actual project uses generally when the system additionally builds the small current capacity power frequency auxiliary pump,small current capacity facilities and so on frequency conversion auxiliary pump, barometric pressure pot maintain the micro current capacity the system pressure.To the different system micro current capacity question should the special details concrete analysis, and carries on the overall evaluation to the disposable investment and the long-term operating cost to be able to make the reasonable solution.In the frequency conversion velocity modulation for in the aqueous system design process, should choose the pump reasonably according to the service pipe net characteristic, achieved in satisfies the operation requirements under the premise, both saves the goal which the investment and conserves energy.MM420变频器在给水系统的几点节能措施-南京航大意航科技股份有限公司由于变频调速给水系统不需要建造传统给水系统的高位水箱、水塔，避免了二次污染并减少了土建投资，而且设计得合理能达到较好的节能效果。
毕业设计(论文)外文资料翻译(学生用)
毕业设计外文资料翻译学院：信息科学与工程学院专业：软件工程姓名： XXXXX学号： XXXXXXXXX外文出处： Think In Java (用外文写)附件： 1.外文资料翻译译文；2.外文原文。
附件1：外文资料翻译译文网络编程历史上的网络编程都倾向于困难、复杂，而且极易出错。
程序员必须掌握与网络有关的大量细节，有时甚至要对硬件有深刻的认识。
一般地，我们需要理解连网协议中不同的“层”（Layer）。
而且对于每个连网库，一般都包含了数量众多的函数，分别涉及信息块的连接、打包和拆包；这些块的来回运输；以及握手等等。
这是一项令人痛苦的工作。
但是，连网本身的概念并不是很难。
我们想获得位于其他地方某台机器上的信息，并把它们移到这儿；或者相反。
这与读写文件非常相似，只是文件存在于远程机器上，而且远程机器有权决定如何处理我们请求或者发送的数据。
Java最出色的一个地方就是它的“无痛苦连网”概念。
有关连网的基层细节已被尽可能地提取出去，并隐藏在JVM以及Java的本机安装系统里进行控制。
我们使用的编程模型是一个文件的模型；事实上，网络连接（一个“套接字”）已被封装到系统对象里，所以可象对其他数据流那样采用同样的方法调用。
除此以外，在我们处理另一个连网问题——同时控制多个网络连接——的时候，Java内建的多线程机制也是十分方便的。
本章将用一系列易懂的例子解释Java的连网支持。
15.1 机器的标识当然，为了分辨来自别处的一台机器，以及为了保证自己连接的是希望的那台机器，必须有一种机制能独一无二地标识出网络内的每台机器。
早期网络只解决了如何在本地网络环境中为机器提供唯一的名字。
但Java面向的是整个因特网，这要求用一种机制对来自世界各地的机器进行标识。
为达到这个目的，我们采用了IP（互联网地址）的概念。
IP以两种形式存在着：(1) 大家最熟悉的DNS（域名服务）形式。
我自己的域名是。
所以假定我在自己的域内有一台名为Opus的计算机，它的域名就可以是。
单片机基础毕业设计外文翻译
本科生毕业设计（论文）外文翻译毕业设计题目：外文题目：Fundamentals of Single-chip Microcomputer 译文题目：单片机基础学院：信息科学与工程学院专业班级：电子信息工程0802班学生姓名：指导教师：外文原文Fundamentals of Single-chip MicrocomputerDr. Dobbs MacintoshJournalAbstractT h e s i n gl e-chi p m i c r o com pu t er i s t h e cul m i na t i on of bo t h t h e d e v el opm e nt o f t h e di gi t al c om p ut e r a nd t h e i nt e gra t e d c i r c ui t a rgu a b l y t h e t ow m o st s i gn i fi c ant i nv en t i on s of t h e 20t h ce n t u r y .T h es e t o w t yp e s o f a rc hi t e c t u r e a r e fo un d i n s i n gl e-c hi p m i c r o com pu t e r.S om e e m p l o y t h e s pl i t p ro gr a m/d at a m em o r y o f t h e H a r v a rd a r ch i t e ct u r e, s ho wn i n F i g.3-5A-1, ot h er s f o l l o w t he p hi l o so ph y,w i d e l y a d a p t ed f o r ge n e r al-pu rp os e com p ut e rs and m i c r op r oc e s s o rs,of m ak i n g n o l o gi c al di s t i nc t i on be t w ee n p ro gr a m a n d d at a m em o r y a s i n t h e P r i n c et on ar c hi t e ct u r e.In ge n e r a l t er m s a si n gl e-c hi p m i cro c om put e r i s c ha r ac t e ri z ed b y t h e i n co r po r at i o n o f al l t h e u ni t s o f a c om put e r i n t o a s i n gl e d e vi c e.Keyword: Single-chip Microcomputer ROM RAM Programming Algorithm Features• Compatible with MCS-51™ Products• 4K Bytes of In-System Reprogrammable Flash Memory– Endurance: 1,000 Write/Erase Cycles• Fully Static Operation: 0 Hz to 24 MHz• Three-level Program Memory Lock• 128 x 8-bit Internal RAM• 32 Programmable I/O Lines• Two 16-bit Timer/Counters• Six Interrupt Sources• Programmable Serial Channel• Low-power Idle and Power-down ModesDescriptionThe AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4Kbytes of Flash programmable and erasable read only memory (PEROM). The deviceis manufactured using Atmel’s high-density nonvolatile memory technology and iscompatible with the industry-standard MCS-51 instruction set and pinout. Theon-chipFlash allows the program memory to be reprogrammed in-system or by a conventionalnonvolatile memory programmer. By combining a versatile 8-bit CPU with Flashon a monolithic chip, the Atmel AT89C51 is a powerful microcomputer which providesa highly-flexible and cost-effective solution to many embedded control applications.The AT89C51 provides the following standard features: 4Kbytes of Flash, 128 bytes of RAM, 32 I/O lines, two 16-bittimer/counters, a five vector two-level interrupt architecture,a full duplex serial port, on-chip oscillator and clock circuitry.In addition, the AT89C51 is designed with static logicfor operation down to zero frequency and supports twosoftware selectable power saving modes. The Idle Modestops the CPU while allowing the RAM, timer/counters,serial port and interrupt system to continue functioning. ThePower-down Mode saves the RAM contents but freezesthe oscillator disabling all other chip functions until the nexthardware reset.Pin ConfigurationsBlock DiagramPin DescriptionVCCSupply voltage.GNDGround.Port 0Port 0 is an 8-bit open-drain bi-directional I/O port. As anoutput port, each pin can sink eight TTL inputs. When 1sare written to port 0 pins, the pins can be used as highimpedanceinputs.Port 0 may also be configured to be the multiplexed loworderaddress/data bus during accesses to external programand data memory. In this mode P0 has internalpullups.Port 0 also receives the code bytes during Flash programming,and outputs the code bytes during programverification. External pullups are required during program verification.Port 1Port 1 is an 8-bit bi-directional I/O port with internal pullups.The Port 1 output buffers can sink/source four TTL inputs.When 1s are written to Port 1 pins they are pulled high bythe internal pullups and can be used as inputs. As inputs,Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pullups.Port 1 also receives the low-order address bytes during Flash programming and verification.Port 2Port 2 is an 8-bit bi-directional I/O port with internal pullups.The Port 2 output buffers can sink/source four TTL inputs.When 1s are written to Port 2 pins they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pullups.Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses (MOVX @DPTR). In this application, it uses strong internal pullups when emitting 1s. During accesses to external data memory that use 8-bit addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register.Port 2 also receives the high-orderaddress bits and some control signals during Flash programming and verification.Port 3Port 3 is an 8-bit bi-directional I/O port with internal pullups.The Port 3 output buffers can sink/source four TTL inputs.When 1s are written to Port 3 pins they are pulled high by the internal pullups and can be used as inputs. As inputs,Port 3 pins that are externally being pulled low will source current (IIL) because of the pullups.Port 3 also serves the functions of various special features of the AT89C51 as listed below:Port 3 also receives some control signals for Flash programmingand verification.ALE/PROGAddress Latch Enable output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming.In normal operation ALE is emitted at a constant rate of 1/6the oscillator frequency, and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external Data Memory.If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode.PSENProgram Store Enable is the read strobe to external program memory.When theAT89C51 is executing code from external programmemory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory.EA/VPPExternal Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH.Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions. This pin also receives the 12-volt programming enable voltage (VPP) during Flash programming, for parts that require 12-volt VPP.XTAL1Input to the inverting oscillator amplifier and input to the internal clock operating circuit.XTAL2Output from the inverting oscillator amplifier.Oscillator CharacteristicsXTAL1 and XTAL2 are the input and output, respectively,of an inverting amplifier which can be configured for use as an on-chip oscillator, as shown in Figure 1. Either a quartz crystal or ceramic resonator may be used. To drive the device from an external clock source, XTAL2 should be left unconnected while XTAL1 is driven as shown in Figure 2. There are no requirements on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high and low time specifications must be observed.Idle ModeIn idle mode, the CPU puts itself to sleep while all the onchip peripherals remain active. The mode is invoked by software. The content of the on-chip RAM and all the special functions registers remain unchanged during this mode. The idle mode can be terminated by any enabled interrupt or by a hardware reset. It should be noted that when idle is terminated by a hard ware reset, the device normally resumes programexecution,from where it left off, up to two machine cycles before the internal reset algorithm takes control. On-chip hardware inhibits access to internal RAM in this event, but access to the port pins is not inhibited. To eliminate the possibility of an unexpected write to a port pin when Idle is terminated by reset, the instruction following the one that invokes Idle should not be one that writes to a port pin or to external memory.Figure 1. Oscillator ConnectionsFigure 2. External Clock Drive ConfigurationPower-down ModeIn the power-down mode, the oscillator is stopped, and the instruction that invokes power-down is the last instruction executed. The on-chip RAM and Special Function Registers retain their values until the power-down mode is terminated. The only exit from power-down is a hardware reset. Reset redefines the SFRs but does not change the on-chip RAM. The reset should not be activated before VCC is restored to its normal operating level and must be held active long enough to allow the oscillator to restart and stabilize.Program Memory Lock BitsOn the chip are three lock bits which can be left unprogrammed (U) or can be programmed (P) to obtain the additional features listed in the table below.When lock bit 1 is programmed, the logic level at the EA pin is sampled and latched during reset. If the device is powered up without a reset, the latch initializes to a random value, and holds that value until reset is activated. It is necessary that the latched value of EA be in agreement with the current logic level at that pin in order for the device to function properly.Programming the FlashThe AT89C51 is normally shipped with the on-chip Flash memory array in the erased state (that is, contents = FFH) and ready to be programmed. The programming interface accepts either a high-voltage (12-volt) or a low-voltage (VCC) program enable signal. The low-voltage programming mode provides a convenient way to program theAT89C51 inside the user’s system, while the high-voltage programming mode is compatible with conventional thirdparty Flash or EPROM programmers. The AT89C51 is shipped with either the high-voltage or low-voltage programming mode enabled. The respective top-side marking and device signature codes are listed in the following table.The AT89C51 code memory array is programmed byte-bybyte in either programming mode. To program any nonblank byte in the on-chip Flash Memory, the entire memory must be erased using the Chip Erase Mode.Programming Algorithm: Before programming the AT89C51, the address, data and control signals should be set up according to the Flash programming mode table and Figure 3 and Figure 4. To program the AT89C51, take the following steps.1. Input the desired memory location on the address lines.2. Input the appropriate data byte on the data lines.3. Activate the correct combination of control signals.4. Raise EA/VPP to 12V for the high-voltage programming mode.5. Pulse ALE/PROG once to program a byte in the Flash array or the lock bits. The byte-write cycle is self-timed and typically takes no more than 1.5 ms.Repeat steps 1 through 5, changing the address and data for the entire array or until the end of the object file is reached.Data Polling: The AT89C51 features Data Polling to indicate the end of a write cycle. During a write cycle, an attempted read of the last byte written will result in the complement of the written datum on PO.7. Once the write cycle has been completed, true data are valid on all outputs, and the next cycle may begin. Data Polling may begin any time after a write cycle has been initiated.Ready/Busy: The progress of byte programming can also be monitored by theRDY/BSY output signal. P3.4 is pulled low after ALE goes high during programming to indicate BUSY. P3.4 is pulled high again when programming is done to indicate READY.Program Verify: If lock bits LB1 and LB2 have not been programmed, the programmed code data can be read back via the address and data lines for verification. The lock bits cannot be verified directly. Verification of the lock bits is achieved by observing that their features are enabled.Chip Erase: The entire Flash array is erased electrically by using the proper combination of control signals and by holding ALE/PROG low for 10 ms. The code array is written with all “1”s. The chip erase operation must be executed before the code memory can be re-programmed.Reading the Signature Bytes: The signature bytes are read by the same procedure as a normal verification of locations 030H, 031H, and 032H, except that P3.6 and P3.7 must be pulled to a logic low. The values returned are as follows.(030H) = 1EH indicates manufactured by Atmel(031H) = 51H indicates 89C51(032H) = FFH indicates 12V programming(032H) = 05H indicates 5V programmingProgramming InterfaceEvery code byte in the Flash array can be written and the entire array can be erasedby using the appropriate combination of control signals. The write operation cycle is selftimed and once initiated, will automatically time itself to completion. All major programming vendors offer worldwide support for the Atmel microcontroller series. Please contact your local programming vendor for the appropriate software revision.外文资料翻译译文单片机基础摘要：单片机是电脑和集成电路发展的巅峰，有据可查的是它们也是20世纪最意义的两大发明。
计算机专业毕业设计论文外文文献中英文翻译——java对象
1 . Introduction To Objects1.1The progress of abstractionAll programming languages provide abstractions. It can be argued that the complexity of the problems you’re able to solve is directly related to the kind and quality of abstraction。
By “kind” I mean，“What is it that you are abstracting?” Assembly language is a small abstraction of the underlying machine. Many so—called “imperative” languages that followed （such as FORTRAN，BASIC, and C) were abstractions of assembly language。
These languages are big improvements over assembly language，but their primary abstraction still requires you to think in terms of the structure of the computer rather than the structure of the problem you are trying to solve。
The programmer must establish the association between the machine model (in the “solution space，” which is the place where you’re modeling that problem, such as a computer) and the model of the problem that is actually being solved (in the “problem space,” which is the place where the problem exists). The effort required to perform this mapping, and the fact that it is extrinsic to the programming language，produces programs that are difficult to write and expensive to maintain，and as a side effect created the entire “programming methods” industry.The alter native to modeling the machine is to model the problem you’re trying to solve。
电子信息毕业设计外文翻译--微型计算机控制系统(单片机控制系统)
毕业设计外文资料翻译Graduation design foreign language translation学院：电气工程与自动化学院专业班级：电子信息科学与技术三班学生姓名：学号：指导教师：外文资料：Microcomputer SystemsElectronic systems are used for handing information in the most general sense; this information may be telephone conversation, instrument read or a company‟s accounts, but in each case the same main type of operation are involved: the processing, storage and transmission of information. in conventional electronic design these operations are combined at the function level; for example a counter, whether electronic or mechanical, stores the current and increments it by one as required. A system such as an electronic clock which employs counters has its storage and processing capabilities spread throughout the system because each counter is able to store and process numbers.Present day microprocessor based systems depart from this conventional approach by separating the three functions of processing, storage, and transmission into different section of the system. This partitioning into three main functions was devised by V on Neumann during the 1940s, and was not conceived especially for microcomputers. Almost every computer ever made has been designed with this structure, and despite the enormous range in their physical forms, they have all been of essentially the same basic design.In a microprocessor based system the processing will be performed in the microprocessor itself. The storage will be by means of memory circuits and the communication of information into and out of the system will be by means of special input/output(I/O) circuits. It would be impossible to identify a particular piece of hardware which performed the counting in a microprocessor based clock because the time would be stored in the memory and incremented at regular intervals but the microprocessor. However, the software which defined the system‟s behavior would contain sections th at performed as counters. The apparently rather abstract approach to the architecture of the microprocessor and its associated circuits allows it to be very flexible in use, since the system is defined almost entirely software. The design process is largely one of software engineering, and the similar problems of construction and maintenance which occur inconventional engineering are encountered when producing software.The figure1-1 illustrates how these three sections within a microcomputer are connected in terms of the communication of information within the machine. The system is controlled by the microprocessor which supervises the transfer of information between itself and the memory and input/output sections. The external connections relate to the rest (that is, the non-computer part) of the engineering system.Fig.1-1 Three Sections of a Typical Microcomputer Although only one storage section has been shown in the diagram, in practice two distinct types of memory RAM and ROM are used. In each case, the word …memory‟ is rather inappropriate since a computers memory is more like a filing cabinet in concept; information is stored in a set of numbered …boxes‟ and it is referenced by the serial number of the …box‟ in question.Microcomputers use RAM (Random Access Memory) into which data can be written and from which data can be read again when needed. This data can be read back from the memory in any sequence desired, and not necessarily the same order in which it was written, hence the expres sion …random‟ access memory. Another type of ROM (Read Only Memory) is used to hold fixed patterns of information which cannot be affected by the microprocessor; these patterns are not lost when power is removed and are normally used to hold the program which defines the behavior of a microprocessor based system. ROMs can be read like RAMs, but unlike RAMs they cannot be used to store variable information. Some ROMs have their data patterns put in during manufacture, while others are programmable by the user by means of special equipment and are called programmable ROMs. The widely used programmable ROMs are erasable by means of special ultraviolet lamps and are referred to as EPROMs, short for Erasable Programmable Read Only Memories. Other new types of device can be erased electrically without the need for ultraviolet light, which are called Electrically Erasable Programmable Read OnlyMemories, EEPROMs.The microprocessor processes data under the control of the program, controlling the flow of information to and from memory and input/output devices. Some input/output devices are general-purpose types while others are designed for controlling special hardware such as disc drives or controlling information transmission to other computers. Most types of I/O devices are programmable to some extent, allowing different modes of operation, while some actually contain special-purpose microprocessors to permit quite complex operations to be carried out without directly involving the main microprocessor.The microprocessor processes data under the control of the program, controlling the flow of information to and from memory and input/output devices. Some input/output devices are general-purpose types while others are designed for controlling special hardware such as disc drives or controlling information transmission to other computers. Most types of I/O devices are programmable to some extent, allowing different modes of operation, while some actually contain special-purpose microprocessors to permit quite complex operations to be carried out without directly involving the main microprocessor.The microprocessor , memory and input/output circuit may all be contained on the same integrated circuit provided that the application does not require too much program or data storage . This is usually the case in low-cost application such as the controllers used in microwave ovens and automatic washing machines . The use of single package allows considerable cost savings to e made when articles are manufactured in large quantities . As technology develops , more and more powerful processors and larger and larger amounts of memory are being incorporated into single chip microcomputers with resulting saving in assembly costs in the final products . For the foreseeable future , however , it will continue to be necessary to interconnect a number of integrated circuits to make a microcomputer whenever larger amounts of storage or input/output are required.Another major engineering application of microcomputers is in process control. Here the presence of the microcomputer is usually more apparent to the user because provision is normally made for programming the microcomputer for the particular application. In process control applications the benefits lf fitting the entire system on to single chip are usually outweighed by the high design cost involved, because this sort lf equipment is produced in smaller quantities. Moreover, process controllers are usually more complicatedso that it is more difficult to make them as single integrated circuits. Two approaches are possible; the controller can be implemented as a general-purpose microcomputer rather like a more robust version lf a hobby computer, or as a …packaged‟ system, signed for replacing controllers based on older technologies such as electromagnetic relays. In the former case the system would probably be programmed in conventional programming languages such as the ones to9 be introduced later, while in the other case a special-purpose language might be used, for example one which allowed the function of the controller to be described in terms of relay interconnections, In either case programs can be stored in RAM, which allows them to be altered to suit changes in application, but this makes the overall system vulnerable to loss lf power unless batteries are used to ensure continuity of supply. Alternatively programs can be stored in ROM, in which case they virtually become part of the electronic …hardware‟ and are often referred to as firmware. More sophisticated process controllers require minicomputers for their implementation, although the use lf large scale integrated circuits …the distinction between mini and microcomputers, Products and process controllers of various kinds represent the majority of present-day micro computer applications, the exact figures depending on one‟s interpretation of the word …product‟. Virtually all engineering and scientific uses of microcomputers can be assigned to one or other of these categories. But in the system we most study Pressure and Pressure Transmitters. Pressure arises when a force is applied over an area. Provided the force is one Newton and uniformly over the area of one square meters, the pressure has been designated one Pascal. Pressure is a universal processing condition. It is also a condition of life on the planet: we live at the bottom of an atmospheric ocean that extends upward for many miles. This mass of air has weight, and this weight pressing downward causes atmospheric pressure. Water, a fundamental necessity of life, is supplied to most of us under pressure. In the typical process plant, pressure influences boiling point temperatures, condensing point temperatures, process efficiency, costs, and other important factors. The measurement and control of pressure or lack of it-vacuum-in the typical process plant is critical.The working instruments in the plant usually include simple pressure gauges, precision recorders and indicators, and pneumatic and electronic pressure transmitters. A pressure transmitter makes a pressure measurement and generates either a pneumatic orelectrical signal output that is proportional to the pressure being sensed.In the process plant, it is impractical to locate the control instruments out in the place near the process. It is also true that most measurements are not easily transmitted from some remote location. Pressure measurement is an exception, but if a high pressure of some dangerous chemical is to be indicated or recorded several hundred feet from the point of measurement, a hazard may be from the pressure or from the chemical carried.To eliminate this problem, a signal transmission system was developed. This system is usually either pneumatic or electrical. And control instruments in one location. This makes it practical for a minimum number of operators to run the plant efficiently.When a pneumatic transmission system is employed, the measurement signal is converted into pneumatic signal by the transmitter scaled from 0 to 100 percent of the measurement value. This transmitter is mounted close to the point of measurement in the process. The transmitter output-air pressure for a pneumatic transmitter-is piped to the recording or control instrument. The standard output range for a pneumatic transmitter is 20 to 100kPa, which is almost universally used.When an electronic pressure transmitter is used, the pressure is converted to electrical signal that may be current or voltage. Its standard range is from 4 to 20mA DC for current signal or from 1 to 5V DC for voltage signal. Nowadays, another type of electrical signal, which is becoming common, is the digital or discrete signal. The use of instruments and control systems based on computer or forcing increased use of this type of signal.Sometimes it is important for analysis to obtain the parameters that describe the sensor/transmitter behavior. The gain is fairly simple to obtain once the span is known. Consider an electronic pressure transmitter with a range of 0～600kPa.The gain isdefined as the change in output divided by the change in input. In this case, the output is electrical signal (4～20mA DC) and the input is process pressure (0～600kPa). Thus the gain. Beside we must measure Temperature Temperature measurement is important in industrial control, as direct indications of system or product state and as indirect indications of such factors as reaction rates, energy flow, turbine efficiency, and lubricant quality. Present temperature scales have been in use for about 200 years, the earliestkPamA kPa mA kPa kPa mA mA Kr 027.0600160600420==--=instruments were based on the thermal expansion of gases and liquids. Such filled systems are still employed, although many other types of instruments are available. Representative temperature sensors include: filled thermal systems, liquid-in-glass thermometers, thermocouples, resistance temperature detectors, thermostats, bimetallic devices, optical and radiation pyrometers and temperature-sensitive paints.Advantages of electrical systems include high accuracy and sensitivity, practicality of switching or scanning several measurements points, larger distances possible between measuring elements and controllers, replacement of components(rather than complete system), fast response, and ability to measure higher temperature. Among the electrical temperature sensors, thermocouples and resistance temperature detectors are most widely used.DescriptionThe AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel‟s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C51 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications. Function characteristicThe AT89C51 provides the following standard features: 4K bytes of Flash, 128 bytes of RAM, 32 I/O lines, two 16-bit timer/counters, a five vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator and clock circuitry. In addition, the AT89C51 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The Power-down Mode saves the RAM contents but freezes the oscillator disabling all other chip functions until the next hardware reset.Pin DescriptionVCC：Supply voltage.GND：Ground.Port 0：Port 0 is an 8-bit open-drain bi-directional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as highimpedance inputs.Port 0 may also be configured to be the multiplexed loworder address/data bus during accesses to external program and data memory. In this mode P0 has internal pullups.Port 0 also receives the code bytes during Flash programming,and outputs the code bytes during programverification. External pullups are required during programverification.Port 1Port 1 is an 8-bit bi-directional I/O port with internal pullups.The Port 1 output buffers can sink/source four TTL inputs.When 1s are written to Port 1 pins they are pulled high by the internal pullups and can be used as inputs. As inputs,Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pullups.Port 1 also receives the low-order address bytes during Flash programming and verification.Port 2Port 2 is an 8-bit bi-directional I/O port with internal pullups.The Port 2 output buffers can sink/source four TTL inputs.When 1s are written to Port 2 pins they are pulled high by the internal pullups and can be used as inputs. As inputs,Port 2 pins that are externally being pulled low will source current, because of the internal pullups.Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses. In this application, it uses strong internal pullupswhen emitting 1s. During accesses to external data memory that use 8-bit addresses, Port 2 emits the contents of the P2 Special Function Register.Port 2 also receives the high-order address bits and some control signals during Flash programming and verification.Port 3Port 3 is an 8-bit bi-directional I/O port with internal pullups.The Port 3 output buffers can sink/source four TTL inputs.When 1s are written to Port 3 pins they are pulled high by the internal pullups and can be used as inputs. As inputs,Port 3 pins that are externally being pulled low will source current (IIL) because of the pullups.Port 3 also serves the functionsof various special features of the AT89C51 as listed below:Port 3 also receives some control signals for Flash programming and verification.RSTReset input. A high on this pin for two machine cycles while the oscillator is running resets the device.ALE/PROGAddress Latch Enable output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming.In normal operation ALE is emitted at a constant rate of 1/6 the oscillator frequency, and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external Data Memory.If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode.PSENProgram Store Enable is the read strobe to external program memory.When the AT89C51 is executing code from external program memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory.EA/VPPExternal Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset.EA should be strapped to VCC for internal program executions.This pin also receives the 12-volt programming enable voltage(VPP) during Flash programming, for parts that require12-volt VPP.XTAL1Input to the inverting oscillator amplifier and input to the internal clock operating circuit. XTAL2Output from the inverting oscillator amplifier.Oscillator CharacteristicsXTAL1 and XTAL2 are the input and output, respectively,of an inverting amplifier which can be configured for use as an on-chip oscillator, as shown in Figure 1.Either a quartz crystal or ceramic resonator may be used. To drive the device from an external clock source, XTAL2 should be left unconnected while XTAL1 is driven as shown in Figure 2.There are no requirements on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high and low time specifications must be observed.中文翻译：微型计算机控制系统（单片机控制系统）广义地说，微型计算机控制系统（单片机控制系统）是用于处理信息的，这种被用于处理的信息可以是电话交谈，也可以是仪器的读数或者是一个企业的帐户，但是各种情况下都涉及到相同的主要操作：信息的处理、信息的存储和信息的传递。
码分多址通信系统、扩频通信外文翻译
中文2800字毕业设计英文翻译专业电子信息工程班级2010级学生姓名学号课题码分多址通信系统的建模、仿真和设计——初始化模块、基站接收模块指导教师2014 年06 月10 日译文原文1.1 The basic concept of spread-spectrum communicationSpread spectrum communication’s basic characteristics, is used to transmit information to the signal bandwidth(W) is far greater than practical required minimum(effective) bandwidth (F∆),as the radio of processing gain P G.=/G P∆FWAs we well know,the ordinary AM,FM,or pulse code modulation,GP value in the area more than 10 times,collectively,the “narrow-band communication”,and spread-spectrum communication GP values as hundred or even thousands of times, can be called “broadband communication”.Due to the spread-spectrum signal,it is very low power transmitters,transmission space mostly drowned in the noise,it is difficult to intercepted by the other receiver ,only spreading codes with the same (or random PN code) receiver, Gain can be dealt with ,and despreading resume the original signal.1.2 The technology superiority of spread-spectrum communication.Strong anti-interference, bit error rate is low. As noted above, the spread spectrum communication system due to the expansion of the transmitter signal spectrum, the receiver despreading reduction signal produced spreading gain, thereby greatly enhancing its interference tolerance. Under the spreading gain, or even negative in the signal-to-noise ratio conditions, can also signal from the noise drowned out Extraction, in the current business communications systems, spread spectrum communications systems, spread spectrum communication is only able to work in a negative signal-to-noise ratio under the conditions of communication .Anti-multi-path interference capability, increase the reliability of system. Spread-spectrum systems as used in the PN has a good correlation, correlation is very weak. Different paths to the transmission signal can easily be separated and may intime and re-alignment phase, formation of several superimposed signal power, thereby improving the system’s performance to receive increased reliability of the system.Easy to use the same frequency, improving the wireless spectrum utilization. Wireless spectrum is very valuable,although long-wave microwave have to be exploited, and still can not meet the needs of community. To this end, countries around the world are designed spectrum management, users can only use the frequency applications,rely on the channel to prevent the division between the channel interference.Due to the use of spread-spectrum communication related receive this high-tech,low signal output power(“a W,as a general-100mW),and will work in the channel noise and thermal noise in the background,easy to duplicate in the same area using the same frequency,can now all share the same narrow-band frequency communication resources.Spread-spectrum communication is digital communication,particularly for digital voice and data transmission with their own encryption, only in the same PN code communication between users, is good for hiding and confidential in nature, facilitating communication business. Easy to use spread-spectrum CDMA communications, voice compression and many other new technologies, more applicable to computer networks and digitization of voice,image information transmission.Communication in the most digital circuits, equipment, highly integrated, easy installation, easy maintenance, but also very compact and reliable. The average failure rate no time was very long.1.3 Spread spectrum communication systemSpread spectrum communication,namely, spread spectrum communications (Spread spectrum communication), with fiber-optic communications,satellite communications,with access to the information age as the three major high-tech communications transmission. Spread spectrum communication is to send the information to be pseudo-random data is coded(Spread spectrum sequence: spread sequence) modulation, spread spectrum and then the realization of transmission; thereceiving end is using the same modem code and related processing, the restoration of the original data. Spread spectrum communication system has three main characteristics.(1) Carrier is an unpredictable, or so-called pseudo-random broadband signal.(2) Carrier data bandwidth than the modulation bandwidth is much wilder.(3) Receiving process is generated by local broadband carrier signal and receiving a copy of the signal to the broadband signal to achieve.The main way of spread spectrum are as follows: Direct Sequence Spread Spectrum(DSSS) using high-speed pseudo-random code on to the low-speed data transmission spread spectrum modulation; Frequency-hopping system using pseudo-random code to control the carrier frequency in a wider band of the change; TH is the data transmission time slot is a pseudo-random; chirp frequency system is a linear extension of the process of change. Combination of a number of ways of hybrid systems are often applied.The most important measure pf spread-spectrum system is an indicator of spreading gain, also known as processing gain. It is precisely because of the spread spectrum system itself with its performance characteristics with a series of advantages.1.4 Code division multiple accessCode division multiple access (CDMA) is a channel access method used by various radio communication technologies. It should not be confused with the mobile phone standards called cdmaOne, CDMA2000(the 3G evolution of cdmaOne) and WCDMA (the 3Gstandard used by GSM carrier), which are often referred to as simply CDMA, and use CDMA as an underlying channel access method.One of the concepts in data communication is the idea of allowing several transmitters to send information simultaneously over a signal communication channel. This allows several users to share a band of frequencies (see bandwidth). This concept is called multiple access. CDMA employs spread-spectrum technology and a special coding scheme( where each transmitter is assigned a code) to allow multiple user to be multiplexed over the same physical channel. By contrast, time division multipleaccess (FDMA) divides it by frequency. CDMA is a form of spread-spectrum signaling, since the modulated coded signal has a much higher data bandwidth than the data being communicated.1.5 Spread-spectrum characteristic of CDMAMost modulation schemes try to minimize the bandwidth of this signal since bandwidth is a limited resource. However, spread spectrum use a transmission bandwidth that is several orders of magnitude greater than the minimum required signal bandwidth. One of the initial reasons for doing this was military applications including guidance and communication systems. These system were designed using spread spectrum because if its security and resistance to jamming. Asynchronous CDMA has some level of privacy built in because the signal is spread using a pseudo-random code; this code makes the spread spectrum signals appear random or have noise-like properties. A receiver cannot demodulate this transmission without knowledge of the pseudo-random sequence used to encode the data. CDMA also resistant to jamming. A jamming signal only has a finite amount of power available to jam the signal. The jammer can either spread its energy over the entire bandwidth of the signal or jam only part of the entire signal.CDMA can also effectively reject narrow band interference. Since narrow band interference affects only a small portion of the spread spectrum signal, it can easily be removed through notch filtering without much loss of information. Convolution encoding and interleaving can be used to assist in recovering this lost data. CDMA signal are also resistant to multipath fading. Since the spread spectrum signal occupies a large bandwidth only a small portion of this will undergo fading due to multipath at any give time. Like the narrow band interference this will result in only a small loss of data and can be overcome.Another reason CDMA is resistant to multipath interference is because the delayed versions of the transmitted pseudo-random code, and will thus appear as another user, which is ignored at the receiver. In other words, as long as the multipath channel induces at least one chip of delay, 天the multipath channel induces at least one chip of delay,the multipath signals will arrive at the receiver.in other words, as long as the multipath channel induces at least one chip of delay, the multipath signalswill arrive at the receiver such that they are shifted in time by at least one chip from the intended signal. The correlation properties of the pseudo-random codes are such that this slight delay causes the multipath to appear uncorrelated with the intended signal, and it is thus ignored.Some CDMA devices use a rake receiver, which exploits multipath delay components to improve the performance of the system. A rake receiver combines the information from several correlators, each one tuned to a different path delay, producing a stronger version of the signal than a simple receiver with a signal correlation tuned to the path delay of the strongest signal.Frequency reuse is the ability to reuse the same radio channel frequency at other cell sites within a cellular system. In the FDMA and TDMA systems frequency planning is and important consideration. The frequencies used in different cells must be planned carefully to ensure signals from different cells do not interfere with each other. In a CDMA system, the same frequency can be used in every cell, because channelization is done using the pseudo-random codes. Reusing the same frequency in every cell eliminates the need for frequency planning in a CDMA system; however, planning of the different pseudo-random sequences must be done to ensure that the received signal from one cell does not correlate with the signal from a nearby cell.Since adjacent cell use the same frequencies, CDMA systems have the ability to perform soft handoffs. Soft handoffs allow the mobile telephone to communication simultaneously with two or more cells. The best signal quality in selected until the handoff is complete. This is different from hard handoffs utilized in other cellular systems. In a hard handoff situation, as the mobile telephone approaches a handoff, signal strength may vary abruptly. In contrast, CDMA systems use the soft handoff, which is undetectable and provides a more reliable and higher quality signal.Concluding remarksspread-spectrum technology in the initial stages of development, it has become a theory and a major technological breakthrough. Later in the development process is the improvement and hardware performance improved. Development to thepresent,spread-spectrum technology and the theory has been almost perfect,mainly from the point of view of overall performance, and the other new technology applications. Therefore, the application has been driven by the development of spread-spectrum technology is a power driving force, the future wireless communication systems, such as mobile communication. Wireless LAN, global personal communications, spread-spectrum technology will certainly play an important role.译文正文1.扩频通信系统概述扩频通信，即扩展频谱通信（Spread spectrum communication)，它与光纤通信、卫星通信，一同誉为进入信息时代的三大高技术通信传输方式，扩频通信是将待传送的信息数据被伪随机码调制，实现频谱扩展后再传输；接收端则采用相同的编码进行解调及相关处理，恢复原始信息数据。
院系专业名称英语翻译
院系专业名称英语翻译各学院（原系）中英文对照生物技术学院College of Biotechnology生命科学学院College of Life Science资源环境学院College of Environment and Natural Resources资源环境学院College of Resources and Environment林学院College of Forestry经济贸易学院College of Economics and Trade经济管理学院College of Economics Management工程技术学院College of Polytechnics工程学院College of Engineering农业工程系Department of Agricultural Engineering理学院College of Sciences信息学院College of Information人文学院College of Humanities公管管理学院College of Public Management农学系Department of Agronomy园艺系Department of Horticulture蚕桑系Department of Sericulture艺术设计学院College of Art Design动物科学系Department of Animal Science动物科学学院College of Animal Science兽医学院College of Veterinary Science食品科学系Department of Food Science食品学院College of Food艺术学院College of Arts水利与土木工程学院College of Water Conservancy and Civil Engineering各学位名称对照农学士Agriculture工学士Engineering理学士Sciences哲学士Philosophy经济学士Economics管理学士Management文学士Arts各专业中英文名称对照工商管理Business Administration金融学Finance and 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and Agricultural Chemistry土地规划与利用Land Planning and Utilization农业环境保护Agricultural Environment Protection木材加工Wood Processing经济林Economic Forest农业经济与管理Agricultural Economics and Management贸易经济Trade Economics企业管理Industrial Management国际金融International Trade农业机械化Agricultural Mechanization机械设计Design and Manufacturing汽车运用工程Mobile Application中国社会主义建设Chinese Socialist Construction作物遗传育种Plant Genetics and Breeding果树Pomology动物营养与饲料加工Animal Nutrition and Feed Processing畜牧Animal Husbandry农业工程Agricultural Engineering家具设计与室内装饰Furniture Design and Room Decoration市场策划与营销Market Planning and Marketing土地经济与房地产管理Land Economics and Real Estate Management 精细化工Fine Chemistry财务管理与计算机Financial Management and Computer经贸英语Business English公共关系与秘书Public Relation茶叶加工与贸易Tea Processing And Trade花卉与庭园工程Floriculture And Gardening丝绸与贸易Silk And Trade养禽与禽病防治Poultry Raising And Disease Control微生物发酵技术与贸易Microorganism Fermentation And Trade各学院（原系）主要课程中英文对照生物技术学院(College of Biotechnology)生命科学学院(College of Life Science)化学除草原理与技术Principles and application of weed chemistry control 种子生理Seed physiology组织培养技术Technology of tissue culture果蔬保鲜原理与技术Techniques in preservation of fruit & vegetable植物学Botany酶工程Enzyme engineering植物显微技术Botanical microtechnique细胞生物学Cell biology农田杂草Farmland weed普通生态学General ecology药用植物资源利用Resources and utilization of medicinal plant生物化学研究技术Techniques in biochemistry researches分析与检测技术Technology of test and analysis动物生物化学Animal biochemistry基因工程Genetic engineering文献查阅与综述方法Document searching and reviewing植物生物化学Plant biochemistry蛋白质工程Protein engineering分子生物学Molecular biology植物生物化学实验Plant biochemistry experiment遗传（基因）工程导论Introduction to genetic engineering辐照基础与应用Basis and application of irradiation technology辐射生物学Irradiational biology免疫学Immunology同位素示踪原理及其应用技术Isotopic tracer technique reason and appliance 同位素应用技术Application of isotopes生物电子显微技术Electron microscope and preparation of biological specimen 仪器分析Instrumental analysis现代仪器分析与食品检测Modern instrumental analysis and food inspection农业与温室气体（排放）Agriculture greenhouse effect gases电镜技术Electron microscope technique植物生理学Plant physiology生物物理学Biophysics生态学Ecology核素应用技术The application of nuclide农业电子技术The electronic technology of agriculture食品科学系Department of Food Science食品学院College of Food Science普通微生物学General microbiology农业微生物学Agricultural microbiology食品微生物学Food microbiology环境微生物学Environmental microbiology微生物学实验技术Experimental technique in microbiology食品微生物学实验Microbiological test of food发酵工艺学原理Principles of fermentation technology微生物遗传育种Microbial genetics and strain improvement食品生物化学Biochemistry of food products食品添加济Additives of food products食物酶学Enzyme engineering of food食品分析Food analysis食品营养学Food nutriology食品工艺学Food technology果蔬加工学Processing of fruit and vegetable食品工厂设计The design of food factory乳品学Dairy science &technology蛋品学Egg science & technology肉品学Meat science & technology食品工程原理Principles of food engineering农产品加工学Agricultural products processing technology食品机械与设备Food machinery and equipment食品包装学Food packaging动物科学系Department of Animal Science动物科学学院College of Animal Science动物生理学Animal physiology家畜行为学Ethnology of domestic animals饲料卫生学Feed hygienic配合饲料工艺学Technology of formula feed单胃动物营养学Nutrition of unistomach animals反刍动物营养学Ruminant nutrition饲料检测技术The technique of feed checking and analysis饲料生产学Feed production饲料添加剂学Feed addition家畜饲料学附饲料分析Livestock feeding and feeds analysis饲料原料及加工贮藏Feed ingredients and processing and storage动物饲养学Animal feeding动物营养学基本原理The basal principle of animal nutrition配合饲料技术The technique of formular feed普通畜牧学Animal husbandry淡水养鱼学Culture of fresh-water fish动物学Zoology家禽学Poultry science珍禽学Science of rare birds家畜育种学Poultry breeding家禽孵化学Poultry hatching家畜环境卫生学Livestock environment hygiene牛生产学Cattle production家兔生产学Rabbit production猪生产学Swine production畜牧家畜育种学Animal breeding数量遗传学Quantitative genetics动物遗传学Animal genetics生物统计附试验设计Biological statistics养犬与养猫Canine and feline production家畜繁殖学Animal reproduction动物遗传育种Animal Genetics & Breeding动物生产学Animal production动物医学系(Department of Veterinary Medicine )兽医学院(College of Veterinary Medicine)家畜解剖学The anatomy of the domestic animals禽病学Diseases of poultry家畜病理学The pathology of the domestic animals动物组织学与胚胎学Histology and embryology of the domestic animals 家畜解剖学及组织胚胎学家禽普通病学General diseases of poultry中兽医学Traditional Chinese veterinary medicine兽医临床诊断学Clinical diagnosis of veterinarian家禽传染病学Avian infectious diseases家禽内科学Internal medicine of domestic animals家禽药理学Poultry pharmacology兽医药理学Veterinary pharmacology家畜寄生虫学Parasitology of domestic animals家禽病理学Pathology of poultry兽医产科学Veterinary breeding家畜外科学Veterinary surgery兽医应用免疫学Veterinary applied immunology动物性食品卫生学Animal food hygiene家畜传染病学Infections disease of domestic animals兽医学Veterinary medicine兽医药理学的毒理学Veterinary pharmacy toxicology理学院(College of Science)计算机关系数据库Relationship database计算机应用基础Fundamentals of computer application 计算机应用基础Computer applicationC语言程序设计Programming in C物理化学Physical chemistry有机化学Organic chemistry分析化学Analytical chemistry普通化学General chemistry化工仪表Chemical engineering and meter化学实验Experiment in general chemistry大学物理College physics应用电子技术The application of electronic technology概率论Probability theory线性代数Linear algebra高等数学Advanced mathematics必修课The required courses选修课Optional courses限选课Limited optional courses实践课Practical courses军训Military training专业劳动Work in specialty and for production教学实践Practice in the course生产实习Training for working毕业论文（设计）The thesis or designing for graduation 物化胶化Physical colloid chemistry人文科学学院(College of Humanities)法律基础Fundamentals of law社会主义人生实践The socialist practice in one’s life形势政策教育The education of situation and policy马克思主义原理The course on Marxist theories中国革命史The history of Chinese revolution中国革命的理论与实践The theory and practice of the Chinese revolution社会调查研究理论与方法Theory and method on social investigation and research 中国社会主义建设China’s socialist construction国际贸易International trade经济法学Economic law中国社会主义市场经济概论An introduction to china’s socialist market economy政治经济学Political economics西方经济学Western economics行政管理学Administration management应用写作Practical writing思想教育Ideological education自然科学方法论The methodology of natural science逻辑学Logic农业文献检索Agricultural literature indexing专业英语Special English体育Physical training毛泽东思想概论An introduction to Mao zedong thought邓小平理论概论An introduction to Deng xiaoping theory教育学Pedagogy思想道德修养Thought & moral training教学法Teaching method应用写作Practical writing农业史Agricultural history经济贸易学院(College of Economics and Trade)乡镇企业管理学院(College of Rural Enterprise Management)宏观经济学Macroeconomics微观经济学Microeconomics政治经济学Political economics发展经济学Development economics农业经济学Agricultural economics外国农业经济Foreign agricultural economics中国经济地理Economy geography in China经济法学The law of economics国际商法International commercial law管理信息系统Management information system农业会计学Agricultural accounting消费经济学Consumption economics电算化会计原理Computer accounting成本会计Cost accounting统计学原理Principle of statistics商品流通统计Accounting in commodity circulation金融统计Financial statistics会计学原理Principle of accounting商品流通企业会计Business accounting in commodity circulation财务会计学Financial accounting审计学Auditing银行会计Bank accounting农业政策学Agricultural policy管理学原理Principle management企业学原理Business management房地产经营管理Administration and management of real estate银行经营管理Administration and management of bank商业企业经营管理Business administration and management涉外企业管理Foreign business management资源经济学Resource economics农产品贸易学Agricultural products trade国际贸易International trade进出口贸易实务Practice in import-Export trade市场营销学Marketing国际市场营销学International marketing财政学Public finance国际金融International finance证券投资Investment on securities公共关系学Public relations货币银行学Economics of money and banking投资经济学Economics of investment国际结算International settlement银行信贷学Bank credit财政金融Public finance and monetary economics期货交易理论与实务Theory and practices of futures土地经济学Land economics乡镇企业经济管理The economic management of tow’s enterprise 经济计量学Economical estimate审计学audit农学系(Department of Agronomy)农学院(College of Agriculture)制茶学Manufacture of tea作物育种学（各论）Crop breeding作物育种学（总论）Crop breeding (general discourse)种子学原理Principles of seed science农业管理学Agricultural management农产品综合利用Comprehensive utilization of crop products耕作学Cultivation science经济作物学Industry crop science农业气象基础Agrometeorology遗传学Genetics茶树栽培学Tea cultivation茶叶审评与检验Tea tasting and inspection试验设计与统计分析Experimental designs and statistical analyses农业生态学Agroecology农业自然资源利用及农业区划Utilization of agricultural resources and agricultural regionalization 茶树能种学Tea plant breeding粮食作物学Food crop science茶叶生物化学Biochemistry of tea农业推广学Agricultural popularization农业环境保护Agricultural environmental protection作物栽培学与耕作学Crop cultivation & geoponics蚕桑系(Department of Sericulture)艺术设计学院(College of Art Design)蚕桑综合利用Silkworm-mulberry multipurpose utilization茧丝学Cocoon silk science养蚕学Seri cultural science蚕体解剖生理Anatomy and physiology of silkworm桑树栽培及育种学Mulberry cultivation & breeding桑树病虫害防治学蚕种学Silkworm egg production家蚕遗传育种Silkworm genetic of thremmatology遗传学Genetics蚕病学Silkworm pathology蚕桑学Sericulture园艺系(Department of Horticulture)园艺学院(College of Horticulture)插花艺术Art of floweral arrangement蔬菜育种学Vegetable breeding花卉园艺学Floriculture园艺商品学Marketing of horticultural product园艺设施栽培Horticultural facilities culture植物显微技术Plant microtechnology园艺通论General horticulture园艺昆虫学Horticultural entomology园艺植物育种学Plant breeding in horticulture果树生理学Fruit tree physiology园艺研究法Horticulture studies果树栽培学总论Pomology园艺产品贮藏保鲜学Techniques in preservation of horticultural products园艺植物病理学The pest control of horticulture plant花卉保鲜学Techniques in preservation of flowers & plants园艺植物生理学Horticulture plant pathology蔬菜栽培学Vegetable culture盆景艺术Pruning采后生理Post harvest physiology果树抗性育种专题Special topic on fruit tree resistance园艺植物的生物技术The biotechnique of horticultural plant园艺概论An outline of horticulture蔬菜学Olericulture果树学Pomology工程技术学院(College of polytechnics)工程学院(College of Engineering)建筑电工Architectural electrotechnics电工学Electrotechnics工业电子学Industrial electronics材料力学Strength of materials建筑力学（结构力学部分）Mechanics of structure理论力学Theoretical mechanics机械设计Machinery design机械原理Theory of machine and mechanism画法几何学Drawing geometry机械制图Engineering drawing工程制图Engineering drawing园林工程制图Landscape drawing建筑制图Building drawing液压技术2 Hydraulic technique 2机械工程材料Materials of mechanical engineering机床夹具设计原理Theory of jig design for machine tool冷冲工艺及冷冲模设计Punching technology and punch die design金属切削原理与刀具Principle of l cutting and cutting tool金属工艺学l technology机械制造工艺学Manufactural technology of machinery金属工艺学l technology液压技术1 Hydraulic technique 1汽车维修理论Theory of automobile service汽车运输学Transportation of automobile互换性与测量技术Interchangeability and technical measurement汽车构造Construction of automobile汽车运用工程Automobile application engineering热工基础Fundamental of thermo-technology食品干燥工艺与设备Food drying technology and equipment食品包装机械Food packaging machinery农业机械学Agricultural machinery食品工程原理Theory of food process engineering食品加工机械与设备Foot processing machinery and equipments砼与砌体结构Reinforce concrete建筑构造Structure of building建筑材料Constructional material建筑施工技术与施工组织Technology and planning of building operation单层工业厂房排架结构设计The design of single-factory building with d structure 高层建筑结构设计Design of high rise building民用建筑设计原理Design of civil architecture农业系统工程及管理工程Systems engineering and management engineering资源环境学院(College of Resources and Environment)环境监测Environmental monitoring土壤农业化学Agrochemistry analysis生产布局学原理Principle of productive distribution城镇建设用地管理Management of land urban construction城市规划原理Principle of urban planning资源经济学Resources economics经济地理Economic geography土地资源调查Land resources survey地图绘编Map establishment遥感技术基础Fundamental of remote sensing technology土地信息系统Land information system地籍管理Land management土地规划学Land planning science土地管理学Land management土地经济学Land economic房地产管理Management of real estate房地产估价Appraisement of real estate固体废物的处理与处置Treatment & disposal wastes城市污泥的农业再循环与生态环境The agricultural recycling of municipal sludge and the ecological environment 大气污染控制工程Air pollution controlling engineering环境质量评价Environmental quality assessment环境化学Environmental chemistry水体污染控制工程Water pollution controlling engineering环境生态Environmental ecology土壤污染与防治Soil pollution环境保护概论Introduction of environmental protection农业环境保护概论Introduction of agricultural environmental protection无土栽培原理与技术Theories and techniques of soilless culture农业化学总论Introduction of agrochemistry作物施肥原理Principles of crop fertilization作物营养研究法Methodology of plant nutrition土壤物理学Soil physics土壤学Pedology环境土壤学Environmental pedology土壤化学Soil chemistry土壤粘粒矿物Mineral of soil clay fration土质学基础Basis of geology土壤地理学Soil geography区域土壤学Regional pedology土壤资源调查Soil resources survey茶树病虫害(病害部分) Tea disease and pest (disease section)植物检疫学Quarantine for pests植物病毒学Plant virology果树病理学Fruit tree pathology果蔬病害Fruit and vegetable diseases植物免疫学Plant immunology普通昆虫学General entomology真菌资源及利用Fungal resources and their utilization除草剂毒理学Toxicology of herbicides植物病害生物防治学Biological prevention and control of plant diseases害虫生物防治Biological control杀菌剂毒理学Toxicology of fungicides植物病害流行学Epidemiology of plant diseases农业螨类学Agricultural acarology害虫综合防治Integrated pest management生物统计学Biometrics城市昆虫学Civil entomology作物抗虫育种原理及应用Principle and application of resistant plant breeding 植物病原细菌学Plant bacteriology植物病理学Plant pathology真菌分类学Taxonomy of fungi植物线虫学Plant nematology农业植物病理学Agricultural phytopathology普通植物病理学General phytopathology果蔬昆虫学Fruit plant & vegetable entomology果蔬贮运病害Fruit and vegetable diseases during storage食用真菌学Edible fung林学院College of Forestry数理统计Mathematical statistics遗传学Genetics树木育种学Forest tree breeding树木育苗学Tree seeds and nursery stock science自然保护区学Science of nature reserve造林学Silviculture林业技术经济学Forestry technology economics森林经营学Forest management林业经济管理学Management of forestry economics林业政策与法规Policies and laws of forestry会计学原理Fundamentals of accounting树木病理学Forest pathology测树学Forest measuration测量学Surveying森林生态学Forest ecology森林土壤学Forest soil science森林经理学Forest management森林昆虫学Forest entomology树木学Dendrology机械设计基础Fundamentals of mechanical design厂内运输Equipment of transit in factory胶合板制造学The manufacturing of plywood木材加工企业管理Forest products management胶粘剂与涂料Adhesive and paint木材学Wood science木材干燥Timber drying木制品生产工艺学Tec manufacturing of wood products纤维板制造学Fiberboard manufacturing technology刨花板制造学The manufacturing of particleboard木材切削原理与刀具The principles of wood cutting and tools木工机械Wood machinery土壤学Soil science经济林育种学Economic forest breeding经济林昆虫学Economic forest entomology经济林病理学Economic forest pathology经济林栽培学Economic forest culture园林设计Parks and gardens design造型艺术Plastic art城市绿地规划City open spaces planning园林树木栽培养护学Garden tree cultivation园林树木学Ornamental dendrology园林专业绘画课Painting of landscape architecture城市规划基础Fundamentals of city planning城市园林绿化经济管理Economic management of urban landscape gardening 风景园林设计初步Elementary landscape architecture design园林植物病理学Ornamental plant pathology园林昆虫学Ornamental plant entomology园林史History of landscape architecture园林工程Landscape architectural engineering土壤学Soil science城市生态学Urban ecology森林保护学Forest protection。
电子信息工程专业毕设 文献翻译 附英文原文
5.3. 时钟独立的显性误差
对于每一个特定的GPS时钟，在每个适用的时间从KF1相位偏差估计值减去 UECC估计值， 去估计其OEIC的相位。 在测量加工， OEIC包含在几部分纳秒内(见 图4)。图4展示了的两种情况下地面工作站时钟S1的OEIC。在蓝线的可见区间和 KF1测距处理显然有别于没有测量的传播间隔。在测量处理期间，KF1估计误差 的观察目标部分包含在几部分纳秒内。OEIC的协方差顺序计算需要每个时间点 的 KF1相位偏差估计误差和UECC估计误差的互协方差矩阵值。 我尚未能计算这
X K 1|K 1 X K 1|K K K 1[ y K 1 y( X K 1|K )]
Hale Waihona Puke （5）5. 难以观察的 GPS 时钟系统
GPS时间是由作战空军（USAF）卡尔曼滤波器处理 GPS伪距测量产生的。 GPS时间是多个GPS时钟的平均相位， 可是， 通过 GPS伪距测量， 每个运行的GPS 时钟的时钟相位是难以观察的，演示如下。GPS导航星的轨道参数是从GPS伪距 观测可观察到的。从GPS伪距测量可以得到USAF（美国空军）卡尔曼滤波器估 计轨道参数和时钟同步参数， 因此以这种方式将状态估计值分为隐式的时钟参数 子集和显式的轨道参数子集。通过应用谢尔曼有关MU函数的定理，演示了这种 分区方式。
4.3.2. 非线性函数 MU
计算 n ×1 矩阵滤波器增益 K K 1 ：
T T 1 K K 1 PK 1|K H K 1 [ H K 1 PK 1| K H K 1 R K 1 ]
（4）
滤波器测量更新 n×1 状态估计矩阵 X K 1|K 1 ，观测 yK+1 得
态估计误差协方差方阵（正特征值）
毕业设计文献翻译完美版
《毕业设计》文献翻译院系：电子电气工程学院学号：021309208姓名：吴骁奕指导教师：曾国辉完成时间：2013/2/15文献翻译021309208 吴骁奕A Flexible LED Driver for Automotive Lighting Applications: IC Design and E xperimental Characterization一个灵活的LED驱动汽车照明应用:集成电路设计和实验特征Abstract—This letter presents a smart driver for LEDs, particularly摘要：这文章提出了一个智能驱动发光二极管，for automotive lighting applications, which avoid ringing尤其是用于避免振荡和超调现象的汽车照明应用上，and overshoot phenomena. To this aim, advanced Soft Start and为了这个目的，在芯片上集成了优化软启动和电流升降控制技术。
Current Slope Control techniques are integrated on-chip. This letter这篇文章讨论了设计于集合于高电压的互补金属氧化半导体上的驱动技术，discusses the driver design integrating in high voltage CMOStechnology, the digital circuitry for programming and electronic用于编程和电子控制单元连接的数字电路以及功率元件提高到10瓦特。
control units interfacing, and the power devices up to 10W. Experimental同时也展示了不同功率等级使用的发光二极管和与不同类型的连接时的实验特征。
毕业设计机电工程系中英文翻译对照
English translationThe E- Behind EverythingElectricity and magnetism run nearly everything we plug in or turn on. Although it’s something we take for granted, it has taken hundreds of years of experimentation and research to reach the point where we flick a switch and the lights go on.People knew about electricity for a long time. Ancient Greeks noticed that if they rubbed a piece of amber, feathers would stick to it. You’ve experienced a similar thing if you’ve ever had your hair stick up straight after you combed it, or had your socks stick together when you removed them from the drier. This is called static electricity, but back then nobody knew how to explain it or what to do with it.Experiments using friction to generate static electricity led to machines that could produce large amounts of static electricity on demand. In 1660 German Otto von made the first electrostatic generator with a ball of sulfur and some cloth. The ball symbolized the earth, and he believed that this little replica of the e arth would shed part of its electric “soul” when rubbed. It worked, and now scientists could study electric shocks and sparks whenever they wanted.As scientists continued to study electricity, they began thinking of it as an invisible fluid and tried to capture and store it. One of the first to do this was Pieter van, Holland. In 1746 he wrapped a water-filled jar with metal foil and discovered that this simple device could store the energy produced by an electrostatic generator. This device became known as the jar. were very important in other people’s experiments, such as Benjamin Franklin’s famous kite experiment. Many people suspected that lightning and static electricity were the same thing, since both crackled and produced bright sparks. In 1752 Franklin attached a key to a kite and flew it in a storm-threatened sky. (NOTE that Franklin did not fly a kite in an actual storm. NEVER do that!) When a thundercloud moved by, the key sparked. This spark charged the jars and proved that lightning was really electricity. Like many experimenters and scientists Franklin used one discovery to make another. Franklin was not the only scientist inspired to conduct experiments with electricity. In the 1780s, the Italian scientist Luigi m ade a dead frog’s leg move by means of an electric current. called this “animal electricity.” He thought that the wet animal tissue generated electricity when it came in contact with metal probes. He even suggested that the soul was actually Italian Alessandro Volta was skeptical of con clusions. In 1799 he discovered that it wasn’t animal tissue alone producing the electric current at all. Volta believed that the current was actually caused by the interaction of water and chemicals in the animal tissue with the metal probes. Volta stacked metal disks separated by layers of cardboard soaked in salt water. This so-called voltaic pile produced an electric current without needing to be charged like a jar. This invention is still around today, but we call it the battery.Volta’s pile was a lot different from the batteries you put in your Discman. It was big, ugly, and messy, but it worked, making Volta the first person to generate electricity with a chemical reaction. His work was so important that the term volt—the unit of electrical tension or pr—is named in his honor. As for Galvani, although he was proven wrong, his work stimulated research on electricity and the body. That research eventually proved that nerves do carry electrical impulses, an important medical discovery. Like electricity, magnetism was baffling to the earliest researchers. Today manufactured magnets are common, but in earlier timesthe only available magnets were rare and mysterious rocks with an unexplainable attraction for bits of iron. Explanations of the way they work sound strange today. For example, in the 1600, English doctor William Gilbert published a book on magnetism. He thought that these strange substances, called “lodestones,” had a soul that accounted for the attraction of a lodestone to iron and steel. The only real use for lodestones was to make compasses, and many thought the compass needle’s movement was in response to its attraction to the earth’s “soul.” By 1800, after many years of study, scientists began wondering if these two mysterious forces—electricity and magnetism—were related. In 1820 Danish physicist Hans Oersted showed that whenever an electric current flows through a wire, it produces a magnetic field around the wire. French mathematician André-Marie used algebra to come up with a mathematical formula to describe this relationship between electricity and magnetism. He was one of the first to develop measuring techniques for electricity. The unit for current, the ampere, abbreviated as amp or as A, is named in his honor. Groundbreaking experiments in electromagnetism were conducted by British scientist Michael Faraday. He showed that when you move a loop of a wire in a magnetic field, a little bit of current flows through the loop for just a moment. This is called induction. Faraday constructed a different version of it called the induction ring. In later years, engineers would use the principle of the induction ring to build electrical transformers, which are used today in thousands of electrical and electronic devices. Faraday also invented a machine that kept a loop of wire rotating near a magnet continuously. By touching two wires to the rotating loop, he could detect the small flow electric current. This machine used induction to produce a flow of current as long as it was in motion, and so it was an electromagnetic generator. However, the amount of electricity it produced was very tiny. There was still another use for induction. Faraday also created a tiny electric motor—too small to do the work of a steam engine but still quite promising. For thousands of years electricity and magnetism were subjects of interest only to experimenters and scientists. Nobody thought of a practical way of using electricity before the 1800s and it was of little interest to most people. But by Faraday’s time invento rs and engineers were gearing up to transform scientific concepts into practical machines.Telegraphs and TelephonesOne of the most important ways that electricity and magnetism have been put to use is making communication faster and easier. In this day o f instant messaging, cell phones, and pagers, it’s hard to imagine a time when messages had to be written and might spend weeks or even months reaching their destination. They had to be carried great distances by ships, wagon, or even by horseback—you coul dn’t just call somebody up to say hello. That all changed when inventors began using electricity and magnetism to find better ways for people to talk to each other. The telegraph was first conceived of in the 1700s, but few people pursued it. By the 1830s, however, advancements in the field of electromagnetism, such as those made by Alessandro Volta and Joseph Henry, created new interest in electromagnetic communication. In 1837, English scientist Charles Wheatstone opened the first com telegraph line between London and Camden Town, a distance of 1.5 miles. Building on, Samuel Morse, an American artist and inventor, designed a line to connect Washington, DC and Baltimore, Maryland in 1844. Morse’s telegraph was a simple device that used a battery, a switch, and a small electromagnet, but it allowed people miles apart to communicate instantly. Although Morse is often credited with inventing the telegraph, his greatest contribution was actually Morse, a special language designed for the telegraph. Morse'scommercialization of the telegraph spread the technology quickly. In 1861 California was connected to the rest of the United States with the first transcontinental telegraph line. Five years later, engineers found a way of spanning the Atlantic Ocean with telegraph lines, thus connecting the United States and Europe. This was an enormous and challenging job. To do it engineers had to use a huge ship called The Great Eastern to lay the cable across the ocean. It was the only ship with enough room to store all that cable. The world was connected by wire before the nation was connected by rail—the transcontinental railroad wasn’t completed until 1869! The telegraph was the key to fast, efficient railroad service. The railroads and the telegraph expanded side-by-side, crisscrossing every continent, except Anta, in the late 1800s. In the late 19th and early 20th centuries, telegraphy became a very lucrative business for companies such as Western Union. It also provided women with new career options. As convenient as the telegraph was, people dreamt of hearing the voices of loved ones who lived far away. Pretty soon, another instrument to communicate across distances was invented. Alexander Graham Bell, a teacher and inventor, worked with the deaf and became fascinated with studying sound. In 1875, Bell discovered a way to convert sound waves to an undulating current that could be carried along wires. This helped him invent the telephone. The first phone conversation was an inadvertent one between Bell and Watson, his ass istant in the next room. After spilling some acid, Bell said “Mr. Watson, come here.I want you.” He patented his device the same year. Early phone service wasn’t as portable and convenient as today’s. At first, telephones we connected in pairs. You could call only one person, and they could only call you. The telephone exchange changed all that. The first exchange was in New Haven, Connecticut in 1878. It allowed people who subscribed to it to call one another. Operators had to connect the calls, but in 1891 an automatic exchange was invented. Some problems had to be solved, though, before long-distance telephoning could work. The main one was that the signal weakened with distance, disappearing if the telephone lines were too long. A solution was found in 1912 with a way to amplify electrical signals, and transcontinental phone calls were possible. A test took place in 1914, and the next year, Bell, who was in New York, called Watson, who was in San Francisco. He said the same thing he had said during the first phone conversation. Watson’s answer? “It will take me five days to get there now!”Plc development1.1 MotivationProgrammable Logic Controllers (PLC), a computing device invented by Richard E. Morley in 1968, have been widely used in industry including manufacturing systems, transportation systems, chemical process facilities, and many others. At that time, the PLC replaced the hardwired logic with soft-wired logic or so-called relay ladder logic (RLL), a programming language visually resembling the hardwired logic, and reduced thereby the configuration time from 6 months down to 6 days [Moody and Morley, 1999].Although PC based control has started to come into place, PLC based control will remain the technique to which the majority of industrial applications will adhere due to its higher performance, lower price, and superior reliability in harsh environments. Moreover, according to a study on the PLC market of Frost and Sullivan [1995], an increase of the annual sales volume to 15 million PLCs per year with the hardware value of more than 8 billion US dollars has been predicted, though the prices of computing hardware is steadily dropping. The inventor of the PLC, Richard E Morley, fairly considers the PLC market as a 5-billion industry at the present time.Though PLCs are widely used in industrial practice, the programming of PLC based control systems is still very much relying on trial-and-error. Alike software engineering, PLC software design is facing the software dilemma or crisis in a similar way. Morley himself emphasized this aspect most forcefully by indicating [Moody and Morley, 1999, p. 110]:`If houses were built like software projects, a single woodpecker could destroy civilization.” Particularly, practical problems in PLC programming are to eliminate software bugs and to reduce the maintenance costs of old ladder logic programs. Though the hardware costs of PLCs are dropping continuously, reducing the scan time of the ladder logic is still an issue in industry so that low-cost PLCs can be used.In general, the productivity in generating PLC is far behind compared to other domains, for instance, VLSI design, where efficient computer aided design tools are in practice. Existent software engineering methodologies are not necessarily applicable to the PLC based software design because PLC-programming requires a simultaneous consideration of hardware and software. The software design becomes, thereby, more and more the major cost driver. In many industrial design projects, more than SO0/a of the manpower allocated for the control system design and installation is scheduled for testing and debugging PLC programs [Rockwell, 1999].In addition, current PLC based control systems are not properly designed to support the growing demand for flexibility and reconfigurability of manufacturing systems. A further problem, impelling the need for a systematic design methodology, is the increasing software complexity in large-scale projects.1.2 Objective and Significance of the ThesisThe objective of this thesis is to develop a systematic software design methodology for PLC operated automation systems. The design methodology involves high-level description based on state transition models that treat automation control systems as discrete event systems, a stepwise design process, and set of design rules providing guidance and measurements to achieve a successful design. The tangible outcome of this research is to find a way to reduce the uncertainty in managing the control software development process, that is, reducing programming and debugging time and their variation, increasing flexibility of the automation systems, and enabling software reusability through modularity. The goal is to overcome shortcomings of current programming strategies that are based on the experience of the individual software developer.A systematic approach to designing PLC software can overcome deficiencies in the traditional way of programming manufacturing control systems, and can have wide ramifications in several industrial applications. Automation control systems are modeled by formal languages or, equivalently, by state machines. Formal representations provide a high-level description of the behavior of the system to be controlled. State machines can be analytically evaluated as to whether or not they meet the desired goals. Secondly, a state machine description provides a structured representation to convey the logical requirements and constraints such as detailed safety rules. Thirdly, well-defined control systems design outcomes are conducive to automatic code generation- An ability to produce control software executable on commercial distinct logic controllers can reduce programming lead-time and labor cost. In particular, the thesis is relevant with respect to the following aspects.Customer-Driven ManufacturingIn modern manufacturing, systems are characterized by product and process innovation, become customer-driven and thus have to respond quickly to changing system requirements. A majorchallenge is therefore to provide enabling technologies that can economically reconfigure automation control systems in response to changing needs and new opportunities. Design and operational knowledge can be reused in real-time, therefore, giving a significant competitive edge in industrial practice.Higher Degree of Design Automation and Software QualityStudies have shown that programming methodologies in automation systems have not been able to match rapid increase in use of computing resources. For instance, the programming of PLCs still relies on a conventional programming style with ladder logic diagrams. As a result, the delays and resources in programming are a major stumbling stone for the progress of manufacturing industry. Testing and debugging may consume over 50% of the manpower allocated for the PLC program design. Standards [IEC 60848, 1999; IEC-61131-3, 1993; IEC 61499, 1998; ISO 15745-1, 1999] have been formed to fix and disseminate state-of-the-art design methods, but they normally cannot participate in advancing the knowledge of efficient program and system design.A systematic approach will increase the level of design automation through reusing existing software components, and will provide methods to make large-scale system design manageable. Likewise, it will improve software quality and reliability and will be relevant to systems high security standards, especially those having hazardous impact on the environment such as airport control, and public railroads.System ComplexityThe software industry is regarded as a performance destructor and complexity generator. Steadily shrinking hardware prices spoils the need for software performance in terms of code optimization and efficiency. The result is that massive and less efficient software code on one hand outpaces the gains in hardware performance on the other hand. Secondly, software proliferates into complexity of unmanageable dimensions; software redesign and maintenance-essential in modern automation systems-becomes nearly impossible. Particularly, PLC programs have evolved from a couple lines of code 25 years ago to thousands of lines of code with a similar number of 1/O points. Increased safety, for instance new policies on fire protection, and the flexibility of modern automation systems add complexity to the program design process. Consequently, the life-cycle cost of software is a permanently growing fraction of the total cost. 80-90% of these costs are going into software maintenance, debugging, adaptation and expansion to meet changing needs [Simmons et al., 1998].Design Theory DevelopmentToday, the primary focus of most design research is based on mechanical or electrical products. One of the by-products of this proposed research is to enhance our fundamental understanding of design theory and methodology by extending it to the field of engineering systems design. A system design theory for large-scale and complex system is not yet fully developed. Particularly, the question of how to simplify a complicated or complex design task has not been tackled in a scientific way. Furthermore, building a bridge between design theory and the latest epistemological outcomes of formal representations in computer sciences and operations research, such as discrete event system modeling, can advance future development in engineering design. Application in Logical Hardware DesignFrom a logical perspective, PLC software design is similar to the hardware design of integrated circuits. Modern VLSI designs are extremely complex with several million parts and a product development time of 3 years [Whitney, 1996]. The design process is normally separated into acomponent design and a system design stage. At component design stage, single functions are designed and verified. At system design stage, components are aggregated and the whole system behavior and functionality is tested through simulation. In general, a complete verification is impossible. Hence, a systematic approach as exemplified for the PLC program design may impact the logical hardware design.1.3 Structure of the ThesisFigure 1.1 illustrates the outline of the following thesis. Chapter 2 clarifies the major challenges and research issues, and discourses the relevant background and terminology. It will be argued that a systematic design of PLC software can contribute to higher flexibility and reconfigurability of manufacturing systems. The important issue of how to deal with complexity in engineering design with respect to designing and operating a system will be debated. The research approach applied in this thesis is introduced starting from a discussion of design theory and methodology and what can be learnt from that field.Chapter 3 covers the state-of-the-art of control technology and the current practice in designing and programming PLC software. The influences of electrical and software engineering are revealed as well as the potentially applicable methods from computer science are discussed. Pros and cons are evaluated and will lead to the conclusion that a new methodology is required that suffices the increasing complexity of PLC software design.Chapter 4 represents the main body of the thesis and captures the essential features of the design methodology. Though design theory is regarded as being in a pre- scientific stage it has advanced in mechanical, software and system engineering with respect to a number of proposed design models and their evaluation throughout real-world examples. Based on a literature review in Chapter 2 and 3 potential applicable design concepts and approaches are selected and applied to context of PLC software design. Axiomatic design is chosen as underlying design concept since it provides guidance for the designer without restriction to a particular design context. To advance the design concept to PLC software design, a formal notation based on statechart formalism is introduced. Furthermore, a design process is developed that arranges the activities needed in a sequential order and shows the related design outcomes.In Chapter 5, a number of case studies are given to demonstrate the applicability of the developed design methodology. The examples are derived from a complex reference system, a flexible assembly system. The achieved insights are evaluated in a concluding paragraph.Chapter 6 presents the developed computerized design tool for PLC software design on a conceptual level. The software is written in Visual Basic by using ActiveX controls to provide modularity and reuse in a web-based collaborative programming environment. Main components of the PLC software are modeling editors for the structural (modular) and the behavioral design, a layout specification interface and a simulation engine that can validate the developed model. Chapter 7 is concluding this thesis. It addresses the achievements with respect to the research objectives and questions. A critical evaluation is given alongside with an outlook for future research issues.电力的故事当我们插上电源,打开旋钮,电和磁差不多在每样东西上都运行着,今天我们知道这是什么,这一些花了人们上百年时间的实验和研究来达到这一点—当我们按下按钮时,光亮已经开始，人们对电的了解已经有很长一段时间了.古希腊人注意到,摩擦一块琥珀,羽毛将能被吸住.你已经经历过相类似的事情,当你梳头时,头发将垂直竖起,当你从干燥机中拿袜子时,袜子也会粘在一起.这被称作静电.但是在以前人们不知道如何解释此类现象或如何应用这种现象，使用摩擦产生的静电来带动机器的实验可以产生大量所需要的静电.在1660年,德国人Otto von Guericke用一个硫磺球和一些布制造了第一台静电发电机.硫磺球象征大地,他深信这种小型地球复制品被摩擦时将流出电的灵魂,他成功了,现在的科学家可以在任何想要的时候来研究电击和电火花.随着科学家们持续对电的研究,他们开始认为它以一种看不见的方式流动,并试图去捕获并储存.第一次去做这项研究的是荷兰Leyden的Pieter van Musschenbroek.1746,他用一个金属箔片包一个装满水的罐子,发现这种简单的设备能储存由静电发电机产生的能量.这个设备后来著名的莱顿瓶.莱顿瓶在其他人的实验中有非常重要的作用.如Benjamin Franklin著名的风筝实验.许多人认为闪电和静电是同一种东西,由于双方碰撞产生明亮的电火花.1752年, Franklin将一把钥匙绑在风筝上,在一个暴风即将来临的天气里放飞(请记住Franklin不是在一个真正的暴风寸中放飞的,永远不要这样做),当一块雷雨云经过时,钥匙被闪电击中,闪电充满莱顿瓶,由此证明闪电实际也是一种电力.同其他实验人和科学家一样, Franklin用一个发现来做另外一个. Franklin并不是唯一的在电力实验方面灵光突现的科学家.18世纪80年代,意大利的科学家Luigi Galvani用电流让一只切断的青蛙的腿移动. Galvani称之为生物电.他认为当潮湿的动物组织同金属探测针接触时产生电能.他甚至大胆预测精神也是一种电能。
毕业设计英文 翻译(原文)
编号：毕业设计(论文)外文翻译（原文）院（系）：桂林电子科技大学专业：电子信息工程学生姓名： xx学号： xxxxxxxxxxxxx 指导教师单位：桂林电子科技大学姓名： xxxx职称： xx2014年x月xx日Timing on and off power supplyusesThe switching power supply products are widely used in industrial automation and control, military equipment, scientific equipment, LED lighting, industrial equipment,communications equipment,electrical equipment,instrumentation, medical equipment, semiconductor cooling and heating, air purifiers, electronic refrigerator, LCD monitor, LED lighting, communications equipment, audio-visual products, security, computer chassis, digital products and equipment and other fields.IntroductionWith the rapid development of power electronics technology, power electronics equipment and people's work, the relationship of life become increasingly close, and electronic equipment without reliable power, into the 1980s, computer power and the full realization of the switching power supply, the first to complete the computer Power new generation to enter the switching power supply in the 1990s have entered into a variety of electronic, electrical devices, program-controlled switchboards, communications, electronic testing equipment power control equipment, power supply, etc. have been widely used in switching power supply, but also to promote the rapid development of the switching power supply technology .Switching power supply is the use of modern power electronics technology to control the ratio of the switching transistor to turn on and off to maintain a stable output voltage power supply, switching power supply is generally controlled by pulse width modulation (PWM) ICs and switching devices (MOSFET, BJT) composition. Switching power supply and linear power compared to both the cost and growth with the increase of output power, but the two different growth rates. A power point, linear power supply costs, but higher than the switching power supply. With the development of power electronics technology and innovation, making the switching power supply technology to continue to innovate, the turning points of this cost is increasingly move to the low output power side, the switching power supply provides a broad space for development.The direction of its development is the high-frequency switching power supply, high frequency switching power supply miniaturization, and switching power supply into a wider range of application areas, especially in high-tech fields, and promote the miniaturization of high-tech products, light of. In addition, the development and application of the switching power supply in terms of energy conservation, resource conservation and environmental protection are of great significance.classificationModern switching power supply, there are two: one is the DC switching power supply; the other is the AC switching power supply. Introduces only DC switching power supply and its function is poor power quality of the original eco-power (coarse) - such as mains power or battery power, converted to meet the equipment requirements of high-quality DC voltage (Varitronix) . The core of the DC switching power supply DC / DC converter. DC switching power supply classification is dependent on the classification of DC / DC converter. In other words, the classification of the classification of the DC switching power supply and DC/DC converter is the classification of essentially the same, the DC / DC converter is basically a classification of the DC switching power supply.DC /DC converter between the input and output electrical isolation can be divided into two categories: one is isolated called isolated DC/DC converter; the other is not isolated as non-isolated DC / DC converter.Isolated DC / DC converter can also be classified by the number of active power devices. The single tube of DC / DC converter Forward (Forward), Feedback (Feedback) two. The double-barreled double-barreled DC/ DC converter Forward (Double Transistor Forward Converter), twin-tube feedback (Double Transistor Feedback Converter), Push-Pull (Push the Pull Converter) and half-bridge (Half-Bridge Converter) four. Four DC / DC converter is the full-bridge DC / DC converter (Full-Bridge Converter).Non-isolated DC / DC converter, according to the number of active power devices can be divided into single-tube, double pipe, and four three categories. Single tube to a total of six of the DC / DC converter, step-down (Buck) DC / DC converter, step-up (Boost) DC / DC converters, DC / DC converter, boost buck (Buck Boost) device of Cuk the DC / DC converter, the Zeta DC / DC converter and SEPIC, the DC / DC converter. DC / DC converters, the Buck and Boost type DC / DC converter is the basic buck-boost of Cuk, Zeta, SEPIC, type DC / DC converter is derived from a single tube in this six. The twin-tube cascaded double-barreled boost (buck-boost) DC / DC converter DC / DC converter. Four DC / DC converter is used, the full-bridge DC / DC converter (Full-Bridge Converter).Isolated DC / DC converter input and output electrical isolation is usually transformer to achieve the function of the transformer has a transformer, so conducive to the expansion of the converter output range of applications, but also easy to achieve different voltage output , or a variety of the same voltage output.Power switch voltage and current rating, the converter's output power is usually proportional to the number of switch. The more the number of switch, the greater the output power of the DC / DC converter, four type than the two output power is twice as large,single-tube output power of only four 1/4.A combination of non-isolated converters and isolated converters can be a single converter does not have their own characteristics. Energy transmission points, one-way transmission and two-way transmission of two DC / DC converter. DC / DC converter with bi-directional transmission function, either side of the transmission power from the power of lateral load power from the load-lateral side of the transmission power.DC / DC converter can be divided into self-excited and separately controlled. With the positive feedback signal converter to switch to self-sustaining periodic switching converter, called self-excited converter, such as the the Luo Yeer (Royer,) converter is a typical push-pull self-oscillating converter. Controlled DC / DC converter switching device control signal is generated by specialized external control circuit.the switching power supply.People in the field of switching power supply technology side of the development of power electronic devices, while the development of the switching inverter technology, the two promote each other to promote the switching power supply annual growth rate of more than two digits toward the light, small, thin, low-noise, high reliability, the direction of development of anti-jamming. Switching power supply can be divided into AC / DC and DC / DC two categories, AC / AC DC / AC, such as inverters, DC / DC converter is now modular design technology and production processes at home and abroad have already matured and standardization, and has been recognized by the user, but AC / DC modular, its own characteristics make the modular process, encounter more complex technology and manufacturing process. Hereinafter to illustrate the structure and characteristics of the two types of switching power supply.Self-excited: no external signal source can be self-oscillation, completely self-excited to see it as feedback oscillation circuit of a transformer.Separate excitation: entirely dependent on external sustain oscillations, excited used widely in practical applications. According to the excitation signal structure classification; can be divided into pulse-width-modulated and pulse amplitude modulated two pulse width modulated control the width of the signal is frequency, pulse amplitude modulation control signal amplitude between the same effect are the oscillation frequency to maintain within a certain range to achieve the effect of voltage stability. The winding of the transformer can generally be divided into three types, one group is involved in the oscillation of the primary winding, a group of sustained oscillations in the feedback winding, there is a group of load winding. Such as Shanghai is used in household appliances art technological production of switching power supply, 220V AC bridge rectifier, changing to about 300V DC filter added tothe collector of the switch into the transformer for high frequency oscillation, the feedback winding feedback to the base to maintain the circuit oscillating load winding induction signal, the DC voltage by the rectifier, filter, regulator to provide power to the load. Load winding to provide power at the same time, take up the ability to voltage stability, the principle is the voltage output circuit connected to a voltage sampling device to monitor the output voltage changes, and timely feedback to the oscillator circuit to adjust the oscillation frequency, so as to achieve stable voltage purposes, in order to avoid the interference of the circuit, the feedback voltage back to the oscillator circuit with optocoupler isolation.technology developmentsThe high-frequency switching power supply is the direction of its development, high-frequency switching power supply miniaturization, and switching power supply into the broader field of application, especially in high-tech fields, and promote the development and advancement of the switching power supply, an annual more than two-digit growth rate toward the light, small, thin, low noise, high reliability, the direction of the anti-jamming. Switching power supply can be divided into AC / DC and DC / DC two categories, the DC / DC converter is now modular design technology and production processes at home and abroad have already matured and standardized, and has been recognized by the user, but modular AC / DC, because of its own characteristics makes the modular process, encounter more complex technology and manufacturing process. In addition, the development and application of the switching power supply in terms of energy conservation, resource conservation and environmental protection are of great significance.The switching power supply applications in power electronic devices as diodes, IGBT and MOSFET.SCR switching power supply input rectifier circuit and soft start circuit, a small amount of applications, the GTR drive difficult, low switching frequency, gradually replace the IGBT and MOSFET.Direction of development of the switching power supply is a high-frequency, high reliability, low power, low noise, jamming and modular. Small, thin, and the key technology is the high frequency switching power supply light, so foreign major switching power supply manufacturers have committed to synchronize the development of new intelligent components, in particular, is to improve the secondary rectifier loss, and the power of iron Oxygen materials to increase scientific and technological innovation in order to improve the magnetic properties of high frequency and large magnetic flux density (Bs), and capacitor miniaturization is a key technology. SMT technology allows the switching power supply has made considerable progress, the arrangement of the components in the circuit board on bothsides, to ensure that the light of the switching power supply, a small, thin. High-frequency switching power supply is bound to the traditional PWM switching technology innovation, realization of ZVS, ZCS soft-switching technology has become the mainstream technology of the switching power supply, and a substantial increase in the efficiency of the switching power supply. Indicators for high reliability, switching power supply manufacturers in the United States by reducing the operating current, reducing the junction temperature and other measures to reduce the stress of the device, greatly improve the reliability of products.Modularity is the overall trend of switching power supply, distributed power systems can be composed of modular power supply, can be designed to N +1 redundant power system, and the parallel capacity expansion. For this shortcoming of the switching power supply running noise, separate the pursuit of high frequency noise will also increase, while the use of part of the resonant converter circuit technology to achieve high frequency, in theory, but also reduce noise, but some The practical application of the resonant converter technology, there are still technical problems, it is still a lot of work in this field, so that the technology to be practical.Power electronics technology innovation, switching power supply industry has broad prospects for development. To accelerate the pace of development of the switching power supply industry in China, it must take the road of technological innovation, out of joint production and research development path with Chinese characteristics and contribute to the rapid development of China's national economy.Developments and trends of the switching power supply1955 U.S. Royer (Roger) invented the self-oscillating push-pull transistor single-transformer DC-DC converter is the beginning of the high-frequency conversion control circuit 1957 check race Jen, Sen, invented a self-oscillating push-pull dual transformers, 1964, U.S. scientists canceled frequency transformer in series the idea of switching power supply, the power supply to the size and weight of the decline in a fundamental way. 1969 increased due to the pressure of the high-power silicon transistor, diode reverse recovery time shortened and other components to improve, and finally made a 25-kHz switching power supply.At present, the switching power supply to the small, lightweight and high efficiency characteristics are widely used in a variety of computer-oriented terminal equipment, communications equipment, etc. Almost all electronic equipment is indispensable for a rapid development of today's electronic information industry power mode. Bipolar transistor made of 100kHz, 500kHz power MOS-FET made, though already the practical switching power supply is currently available on the market, but its frequency to be further improved. Toimprove the switching frequency, it is necessary to reduce the switching losses, and to reduce the switching losses, the need for high-speed switch components. However, the switching speed will be affected by the distribution of the charge stored in the inductance and capacitance, or diode circuit to produce a surge or noise. This will not only affect the surrounding electronic equipment, but also greatly reduce the reliability of the power supply itself. Which, in order to prevent the switching Kai - closed the voltage surge, RC or LC buffers can be used, and the current surge can be caused by the diode stored charge of amorphous and other core made of magnetic buffer . However, the high frequency more than 1MHz, the resonant circuit to make the switch on the voltage or current through the switch was a sine wave, which can reduce switching losses, but also to control the occurrence of surges. This switch is called the resonant switch. Of this switching power supply is active, you can, in theory, because in this way do not need to greatly improve the switching speed of the switching losses reduced to zero, and the noise is expected to become one of the high-frequency switching power supply The main ways. At present, many countries in the world are committed to several trillion Hz converter utility.the principle of IntroductionThe switching power supply of the process is quite easy to understand, linear power supplies, power transistors operating in the linear mode and linear power, the PWM switching power supply to the power transistor turns on and off state, in both states, on the power transistor V - security product is very small (conduction, low voltage, large current; shutdown, voltage, current) V oltammetric product / power device is power semiconductor devices on the loss.Compared with the linear power supply, the PWM switching power supply more efficient process is achieved by "chopping", that is cut into the amplitude of the input DC voltage equal to the input voltage amplitude of the pulse voltage. The pulse duty cycle is adjusted by the switching power supply controller. Once the input voltage is cut into the AC square wave, its amplitude through the transformer to raise or lower. Number of groups of output voltage can be increased by increasing the number of primary and secondary windings of the transformer. After the last AC waveform after the rectifier filter the DC output voltage.The main purpose of the controller is to maintain the stability of the output voltage, the course of their work is very similar to the linear form of the controller. That is the function blocks of the controller, the voltage reference and error amplifier can be designed the same as the linear regulator. Their difference lies in the error amplifier output (error voltage) in the drive before the power tube to go through a voltage / pulse-width conversion unit.Switching power supply There are two main ways of working: Forward transformand boost transformation. Although they are all part of the layout difference is small, but the course of their work vary greatly, have advantages in specific applications.the circuit schematicThe so-called switching power supply, as the name implies, is a door, a door power through a closed power to stop by, then what is the door, the switching power supply using SCR, some switch, these two component performance is similar, are relying on the base switch control pole (SCR), coupled with the pulse signal to complete the on and off, the pulse signal is half attentive to control the pole voltage increases, the switch or transistor conduction, the filter output voltage of 300V, 220V rectifier conduction, transmitted through the switching transformer secondary through the transformer to the voltage increase or decrease for each circuit work. Oscillation pulse of negative semi-attentive to the power regulator, base, or SCR control voltage lower than the original set voltage power regulator cut-off, 300V power is off, switch the transformer secondary no voltage, then each circuit The required operating voltage, depends on this secondary road rectifier filter capacitor discharge to maintain. Repeat the process until the next pulse cycle is a half weeks when the signal arrival. This switch transformer is called the high-frequency transformer, because the operating frequency is higher than the 50HZ low frequency. Then promote the pulse of the switch or SCR, which requires the oscillator circuit, we know, the transistor has a characteristic, is the base-emitter voltage is 0.65-0.7V is the zoom state, 0.7V These are the saturated hydraulic conductivity state-0.1V-0.3V in the oscillatory state, then the operating point after a good tune, to rely on the deep negative feedback to generate a negative pressure, so that the oscillating tube onset, the frequency of the oscillating tube capacitor charging and discharging of the length of time from the base to determine the oscillation frequency of the output pulse amplitude, and vice versa on the small, which determines the size of the output voltage of the power regulator. Transformer secondary output voltage regulator, usually switching transformer, single around a set of coils, the voltage at its upper end, as the reference voltage after the rectifier filter, then through the optocoupler, this benchmark voltage return to the base of the oscillating tube pole to adjust the level of the oscillation frequency, if the transformer secondary voltage is increased, the sampling coil output voltage increases, the positive feedback voltage obtained through the optocoupler is also increased, this voltage is applied oscillating tube base, so that oscillation frequency is reduced, played a stable secondary output voltage stability, too small do not have to go into detail, nor it is necessary to understand the fine, such a high-power voltage transformer by switching transmission, separated and after the class returned by sampling the voltage from the opto-coupler pass separated after class, so before the mains voltage, and after the classseparation, which is called cold plate, it is safe, transformers before power is independent, which is called switching power supply.the DC / DC conversionDC / DC converter is a fixed DC voltage transformation into a variable DC voltage, also known as the DC chopper. There are two ways of working chopper, one Ts constant pulse width modulation mode, change the ton (General), the second is the frequency modulation, the same ton to change the Ts, (easy to produce interference). Circuit by the following categories:Buck circuit - the step-down chopper, the average output voltage U0 is less than the input voltage Ui, the same polarity.Boost Circuit - step-up chopper, the average output voltage switching power supply schematic U0 is greater than the input voltage Ui, the same polarity.Buck-Boost circuit - buck or boost chopper, the output average voltage U0 is greater than or less than the input voltage Ui, the opposite polarity, the inductance transmission.Cuk circuit - a buck or boost chopper, the output average voltage U0 is greater than or less than the input voltage Ui, the opposite polarity, capacitance transmission.The above-mentioned non-isolated circuit, the isolation circuit forward circuits, feedback circuit, the half-bridge circuit, the full bridge circuit, push-pull circuit. Today's soft-switching technology makes a qualitative leap in the DC / DC the U.S. VICOR company design and manufacture a variety of ECI soft-switching DC / DC converter, the maximum output power 300W, 600W, 800W, etc., the corresponding power density (6.2 , 10,17) W/cm3 efficiency (80-90)%. A the Japanese Nemic Lambda latest using soft-switching technology, high frequency switching power supply module RM Series, its switching frequency (200 to 300) kHz, power density has reached 27W/cm3 with synchronous rectifier (MOSFETs instead of Schottky diodes ), so that the whole circuit efficiency by up to 90%.AC / DC conversionAC / DC conversion will transform AC to DC, the power flow can be bi-directional power flow by the power flow to load known as the "rectification", referred to as "active inverter power flow returned by the load power. AC / DC converter input 50/60Hz AC due must be rectified, filtered, so the volume is relatively large filter capacitor is essential, while experiencing safety standards (such as UL, CCEE, etc.) and EMC Directive restrictions (such as IEC, FCC, CSA) in the AC input side must be added to the EMC filter and use meets the safety standards of the components, thus limiting the miniaturization of the volume of AC / DC power, In addition, due to internal frequency, high voltage, current switching, making the problem difficult to solve EMC also high demands on the internal high-density mountingcircuit design, for the same reason, the high voltage, high current switch makes power supply loss increases, limiting the AC / DC converter modular process, and therefore must be used to power system optimal design method to make it work efficiency to reach a certain level of satisfaction.AC / DC conversion circuit wiring can be divided into half-wave circuit, full-wave circuit. Press the power phase can be divided into single-phase three-phase, multiphase. Can be divided into a quadrant, two quadrant, three quadrants, four-quadrant circuit work quadrant.he selection of the switching power supplySwitching power supply input on the anti-jamming performance, compared to its circuit structure characteristics (multi-level series), the input disturbances, such as surge voltage is difficult to pass on the stability of the output voltage of the technical indicators and linear power have greater advantages, the output voltage stability up to (0.5)%. Switching power supply module as an integrated power electronic devices should be selected。
计算机专业毕业设计英文翻译7
clicking on hot spots, it can show the hot spot's specific information. One can also type into the query information based on his need, and get some relevant information. In addition, one can choose to check the three dimensional maps and satellite maps through clicking the mouse. Major functions: User information management: Check the user name and password, set level certification depending on the permissions, allow users of different permissions to login the system via the Internet. The inquiry of Location information: System can provide users with fuzzy inquires and quick location. Map management: Implement loading maps, map inquires, layer management, and other common operations such as distance measurement, and maps zoom, eagle eye, labels, printing, and more. Roam the map: Use the up and down keys to roam any area of the map, or drag-and-drop directly.
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3 Magnification-Based MagnificationThe focus of the previous chapter was to define a nonlinear magnification system using simple modular components joined together to create complex magnification effects. Although this system for nonlinear magnification transformations was successful in reducing complex magnification effects to a set of easy to understand and implement operations, there are some general limitations which the system still has in common with existing nonlinear magnification systems.The first major limitation of the existing nonlinear magnification systems could be referred to as the “tyranny of the foci". Although explicit centers of magni fication are clearly desirable in many cases, this also puts severe limitations on the types of magnification and interaction which can be produced. Interaction becomes an exercise in manipulation of discrete magnifying “lenses", and additional expressiveness of magni fication comes primarily through additional and/or complex lenses, thus increasing the computational cost of computing the overall transformation.A second difficulty encountered with existing systems involves determining the overall effect of complex transformations. A general purpose mechanism would be useful to determine the effects of complex transformations with multiple foci, so that the global effect of the transformations can be determined across the entire space of a domain, rather than just at the centers of magnification or other discrete points.Thirdly, all of the existing nonlinear magnification systems closely tie the method for specifying the magnification to the method used to produce the transformation. In most cases the magnification is only a side-effect of specifying a transformation. These interdependencies create complications for each method. A system in which the magnification values can be specified independently of the transformation mechanism would provide more direct control of the specification, as well as allowing the magnification values to be analyzed, combined and manipulated in a more systematic fashion.In this chapter we will develop further a theory of nonlinear magnification that addresses these issues. In particular, we reduce the concept of nonlinear magnification to a field of scalar magnification values. Broadly speaking, these nonlinear magnification fields provide benefits at two levels. First, they serve as a basis for analyzing the effects of existing techniques, even though their underlying mechanisms may be very different. Second, they directly define space transforming visualizations and can be manipulated in computationally efficient and conceptually effective ways, thus yielding powerful visualization tools.Defining magnification as a field of arbitrary scalar values provides a much greater expressiveness of magnification and ease of manipulation than is possible using other techniques. By removing the restrictions of discrete foci we allow uidly shifting magnifications of arbitrary complexity, and can factor out magnification complexity from the time required to compute suitable transformation functions so that computation is independent of the complexity of the magnification function. We will look at a number of novel ways in which the exibility of these nonlinear magnification fields can be used to create effective visualizations. The techniques presented range from low-level precise specification of magnification, through the creation ofexpressive user-interface techniques, to sophisticated magnification fields constructed by application programs. Many of the results described in this chapter are based on work that was initially reported in [KR97a, KR97b].This chapter has several major sections. First we will develop a formal specification for the relationship between transformation and magnification. Then we will see how the implicit magnification field for a given transformation can be computed. Following this we will investigate an iterative method for computing a transformation from a given magnification field specification, and also examine some performance aspects of that method. Finally we will look at some of the ways in which interfaces can be layered on top of these low level magnification fields.3.1 Magnification FieldsWhen describing nonlinear magnification systems, it is useful to distinguish between magnification and transformation functions, as first described for the one-dimensional case in[LA94]. The transformation function directly stretches and compresses the space, while the magnification function (which is the derivative of the transformation function) represents the magnification values which are implicit in the transformation function. This distinction is central to the work described in this chapter. Converting between magnification and transformation functions in one dimension is a relatively straightforward task, however the situation is much more complicated in two or more dimensions. In the next two sections we will examine techniques for accomplishing these conversions, after introducing some basic definitions and notation. Although this chapter presents results in 2 dimensions, the view-independent nature of the techniques presented here allows for trivial extension to 3 or more dimensions.Before exploring the mathematics for determining the local 2D magnification, it is illustrative to look at the simple 1D case, where the relationship between transformation and magnification functions was first established by Leung and Apperley in [LA94]. In particular, they identify magnification as the derivative of the transformation function. For a transformation function y = f’(x), the derivative is given as:0()()()limm in x f x x f x ra n g len g thf x x d o leng th →+-'== （3.1）Thus for the 1D case, local magnification is computed as the limit of the ratio of lengths. A diagram of this relationship is shown in Figure 3.1. We will extend this result to two dimensions, where instead of ratio of lengths, we will use the ratio of areas to define magnification.Figure 3.1 Transformation and Magnification Relation in 1DAny magnification employs a transformation function t which moves points of a rectangular domain D within a frame ((u; v) = t(x; y)). t is a vector function which can be also be expressed as:⎪⎪⎭⎫ ⎝⎛=⎪⎪⎭⎫ ⎝⎛=),(),(),(y x t y x t v u y x t v u （3.2）Since we want the magnification to be non-occluding, we require that t is at least C continuous, one-to-one and order-preserving (given (u1; v1) = t(x1; y1) and (u2; v2) =t(x2; y2), x1 < x2 implies u1 < u2, and similarly for y). For computational purposes, we deal with t only on a p_q integer grid G, with g :G ! D(g maps the regular grid G into the domain D), and represent a discrete approximation of t with a quadrilateral grid T (T = t o g, where 'o' represents composition). Given a region R in D, we represent the transformation of R via t as t(R) (also called the image of R). This transformation is illustrated in Figure 3.2.A magnification field m is a 2D scalar field of the form z = m(x; y) which gives the regional expansion caused by t around a point. As with t, m is normally represented on G by a quadrilateral mesh M (M = m o g).Informally, we would like our measure for magnification to represent the intuition that magnification in the real world is “how much bigger things get". A sing le scalar value indicating this would be readily analogous to the “power" commonly used for describing lenses. The mathematics that we use to define this magnification should serve to reect this intuitive understanding.The most obvious approach to measuri ng “how much bigger things get" is to compare the area of a region before and after the transformation has been applied and to make magnification the ratio of those areas(())()A rea t R m a g n ifica tia n A rea R = （3.3）This is a direct extension of the definition of magnification in one dimension that provides a single scalar value reecting the intuitive notion of magnification. We can formulate this area-based approach more precisely in terms of limits by creating an area-based derivative as defined below.2(())lim4h o A rea t R m a g n ifica tio n h →= （3.4）Figure 3.2: Nonlinear Transformation of a RegionBy defining magnification in this way however, we can no longer assert that magnification is the true derivative of transformation in 2D. In fact, a true derivative of a 2D transformation function would yield multiple scalar values rather than a single magnification value. Although it would nice if the derivative relationship carried over directly from the 1D case, there are two major reasons why doing so would not provide an appealing definition for magnification:■It does not match “real w orld" perception of magnification as a single scalar value.■It does not reduce complexity of magnification specification in comparison to transformation-based approaches. It will be shown throughout this chapter that having a single scalar value for magnification greatly facilitates manipulation.It should also be noted that by defining magnification as a single scalar value in this way, we lose some information about the original transformation. This means that given a transformation grid T, if we compute the magnification M and then construct a transformation grid T’ from M, we may not end up with identical T and T’. In general, there may be many possible transformations for a given magnification specification. We will see however, that despite this loss of information about the original grid, good results can be obtained by constructing a transformation having the same intrinsic magnification properties.Related to this issue, the area-based measure for magnification that we are using assumes that magnification is uniform locally and does not take into account scaling differences in the x and y directions, so that when scaling a region by d in the x direction and by 1/d in the y direction we will sometimes obtain a magnification value of 1 (depending on the specific area function being used). Although this may present some problems with the local definition of magnification, we will see in Section 3.3 that the implicit gradient of magnification values within the magnification field can provide additional information about such cases when they are part of a larger region that is non-uniformly scaled.Now that we have defined magnification as a ratio of areas, we must also define how to compute the area of a nonlinearly transformed region R in order to find that ratio. In the following section we will calculate an approximation of these areas numerically, here we present the mathematical formulation for the continuous case.We can compute the area of t(R) with the double (area) integral,[()]|()|,xy R u v A rea t R J d A x y =⎰⎰ (3.5)A theorem showing how to find this integral for a nonlinearly transformed region can be found in Chapter 11 of [PM64], where it is used to develop the Change of Variables Theorem. The formulation for the solution of this integral is:,[()]|()|,xy R u v A rea t R J d A x y =⎰⎰ （3.6）There are a number of conditions which must be met for this integral to exist: t must be one-to-one and continuously deferential over the domain D, R must be a closed bounded region in D having some area, and the Jacobian J of t must never be zero (i.e. the transformation must be invertible).Given the integral in Equation 3.6 for finding the area of a nonlinearly transformed region, we can now compute the local magnification as the ratio of the areas of the transformed and original regions:In the following section we will approximate this limit using an area-based function m c which computes the local magnification for each node in T. For computational efficiency, the area-based magnificat ion we use here actually corresponds to the square of the linear “power" sometimes used in describing lenses.3.2 Transformation Grid to Magnification Field ConversionConversion from a given transformation grid T to a magnification mesh M involves numerically approximating an area-based derivative of T. The computation begins with an area function at which, for each node in T, returns an approximation of the area defined by the neighboring nodes. One possibility for this function simply uses the bounding box of the 4-connected neighbors {T(i+1, j), T(i-1, j), T(i, j +1),T(i, j-1)}. If the distance between node T(i, j) at coordinates (x, y) and one of its 4-connected neighbors in an untransformed grid is h, then this area can be defined as (where “." represe nts the dot product):tx(x, y)=|(t(x-h, y)-t(x+h, y)) (1,0)|⨯|(t(x, y-h)-t(x, y+h)) (0, 1)| (3.8)We define Ca to be the constant area associated with any T(i,j) in the untransformed uniform sampling grid:Ca=|((x-h, y)-(x+h, y)) (1,0)|⨯|((x, y-h)-(x, y+h)) (0,1)|=42h(3.9) The approximate magnification value for a point T(i,j) is then given by M(i,j) =m c(g(i,j)) = m c(x,y) = a t(x,y)/Ca. As the mesh resolution approaches infinity, this becomes:),(yxmc =2(,)lim4tha x yh→(3.10)More accurate area calculations are possible, such as explicitly finding the area of the four surrounding cells. In practice however, this increase in accuracy does not normally change the results significantly. Coarser approximations are adequate, as long as the area function is used consistently throughout the system.Figure 3.3 shows an example of a transformation grid and its associated magnification mesh calculated with this method. This technique allows any nonlinear magnification system to create a landscape representation of its implicit magnification values. Elevation-based shading can be used to provide visual cues to the magnification level simply by mapping elevation values into a color/intensity ramp. This is in contrast to perspective based systems such as perspective wall [MRC91], where elevation and magnification do not correspond directly, but are also dependent on viewing parameters.Figure 3.4 shows another example, this time illustrating multiple bounded regions and linear magnification; the transformation grid was generated using the techniques described in [KR96d]. As a further example of how these techniques can be used to determine the implicit magnification generated by existing systems, we use the example of Perspective Wall [MRC91],which is representative of the class of nonlinear magnification systems that are based on a perspective projection of 3D surfaces (other examples include [RM93, CCF95a, MK97]). By sampling a perspective wall transformation function with a regular grid, we obtain a transformation grid which is used to generate the associated magnification mesh (see Figure 3.5).Theseexamples show how transformation and magnification functions can now be tightly coupled across entire domains even for complex transformations. This method is very general purpose in nature, and can be readily applied to any spatial nonlinear magnification system.Figure 3.3:Transformation Grid and Implicit Magnification Field Figure 3.4: Complex Magnification Field Figure 3.5: Perspective Wall MagnificationAs an example of how implicit magnification fields can be used, consider the task of rendering node sizes proportional to the magnification produced by a complex transformation. Proximity to the centers of magnification is not an effective measure on which to base node size, as it does not take into account the effects of multiple transformations and domain or smoothing parameters. By sampling the region around a node however, we can determine the local implicit magnification for that node by finding out whether that region expands or contracts. By sampling uniformly over a space, we create a magnification mesh and can then interpolate the magnification values between nodes to create a continuous magnification field. Any object can be rendered at an appropriate size or level of detail by finding its magnification value in the field. Figure 3.6 shows a simple example where the implicit magnification field is used to determine the size at which to render objects located within a complexly transformed space. Further examples of similar ways in which the implicit magnification field can be used to determine the “detail" with which to render data objects are described in Chapter 4.Figure 3.6: Node Size Proportional to Implicit Magnification3.3 Magnification Field to Transformation Grid ConversionWhile it is a relatively straightforward task to find the implicit magnification mesh M associated with a transformation grid T by computing the area-based derivative,it is a much more complex task to construct a suitable transformation grid given a magnification mesh. Simple perspective projections of these meshes from an aerial viewpoint are not effiective because they may introduce problems of occlusion.In general terms, we want to use the magnification mesh values to construct an order-preserving transformation grid having the same implicit magnification values. There are a number of issues which make this a difficult task. The most fundamental problem involves finding a meaningful way to convert a single magnification value into a two coordinate (x, y) transformation; there are usually many transformations possible for a given magnification. In general, the transformation to magnification conversion is inherently lossy, and hence the result of the magnification to transformation conversion is not uniquely defined. There exist direct methods for solving this problem, but these methods are unsuited to the specific task of generating nonlinear magnification transformations for visualization. Some of the major shortcomings observed with the direct approaches are:■bounded regions of magnification in M should produce bounded regions of transformation in T to preserve a static context■the transformation should be symmetric and centered around magnification maxima, and not constructed relative to some arbitrary boundary of the domain■solutions providing only correct area in T do not preserve desired visual properties of the magnification, such as scale and aspect ratio within regions of linear magnification3 基于放大的放大前一章的重点是定义了一种非线性放大系统。