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This article described the three directions (before, left, right) ultrasonic ranging system is to understand the front of the robot, left and right environment to provide a movement away from the (Similar to GPS Positioning System) A principle of ultrasonic distance measurement 1, the principle of piezoelectric ultrasonic generator Piezoelectric ultrasonic generator is the use of piezoelectric crystal resonators to Ultrasonic generator, the internal structure as shown in Figure 1, it has two piezoelectric chip and a resonance When it's two plus pulse signal, the frequency equal to the intrinsic piezoelectric oscillation frequency chip, the chip will happen piezoelectric resonance, and promote the development of plate vibration resonance, ultrasound is Conversely, if the two are not inter-electrode voltage, when the board received ultrasonic resonance, it will be for vibration suppression of piezoelectric chip, the mechanical energy is converted to electrical signals, then it becomes the ultrasonic 2, the principle of ultrasonic distance measurement Ultrasonic transmitter in a direction to launch ultrasound, in the moment to launch the beginning of time at the same time, the spread of ultrasound in the air, obstacles on his way to return immediately, the ultrasonic reflected wave received by the receiver immediately stop the Ultrasound in the air as the propagation velocity of 340m / s, according to the timer records the time t, we can calculate the distance between the launch distance barrier (s), that is: s = 340t / 2 Ultrasonic Ranging System for the Second Circuit Design System is characterized by single-chip microcomputer to control the use of ultrasonic transmitter and ultrasonic receiver since the launch from time to time, single-chip selection of 8751, economic-to-use, and the chip has 4K of ROM, to facilitate Circuit schematic diagram shown in Figure Draw only the front range of the circuit wiring diagram, left and right in front of Ranging Ranging circuits and the same circuit, it is 1,40 kHz ultrasonic pulse generated with the launch Ranging system using the ultrasonic sensor of piezoelectric ceramic sensors UCM40, its operating voltage of the pulse signal is 40kHz, which by the single-chip implementation of the following procedures to puzel: mov 14h, # 12h; ultrasonic firing continued 200ms here: cpl 0; output 40kHz square wave nop; nop; nop; djnz 14h, here; ret Ranging in front of single-chip termination circuit P0 input port, single chip implementation of the above procedure, the P0 port in a 40kHz pulse output signal, after amplification transistor T, the drive to launch the first ultrasonic UCM40T, issued 40kHz ultrasonic pulse, and the continued launch of Ranging the right and the left side of the circuit, respectively, then input port P1 and P2, the working principle and circuit in front of the same 2, reception and processing of ultrasonic Used to receive the first launch of the first pair UCM40R, the ultrasonic pulse modulation signal into an alternating voltage, the op-amp amplification IC1A and after polarization IC1B to IC IC2 is locked loop with audio decoder chip LM567, internal voltage-controlled oscillator center frequency of f0 = 1/1R8C3, capacitor C4 determine their target R8-conditioning in the launch of the carrier frequency on the LM567 input signal is greater than 25mV, the output from the high jump 8 feet into a low-level, as interrupt request signals to the single-chip Ranging in front of single-chip termination circuit output port INT0 interrupt the highest priority, right or left location of the output circuit with output gate IC3A access INT1 port single-chip, while single-chip P3 and P 4 received input IC3A, interrupted by the process to identify the source of inquiry to deal with, interrupt priority level for the first left right Part of the source code is as follows: receive1: push psw push acc clr ex1; related external interrupt 1 jnb 1, right; P1 pin to 0, ranging from right to interrupt service routine circuit jnb 2, left; P2 pin to 0, to the left ranging circuit interrupt service routine return: SETB EX1; open external interrupt 1 pop? acc pop? psw reti right: ?; right location entrance circuit interrupt service routine ? Ajmp? Return left: ; left Ranging entrance circuit interrupt service routine ? Ajmp? Return 4, the calculation of ultrasonic propagation time When you start firing at the same time start the single-chip circuitry within the timer T0, the use of timer counting function records the time and the launch of ultrasonic reflected wave received When you receive the ultrasonic reflected wave, the receiver circuit outputs a negative jump in the end of INT0 or INT1 interrupt request generates a signal, single-chip microcomputer in response to external interrupt request, the implementation of the external interrupt service subroutine, read the time difference, calculating the distance Some of its source code is as follows: RECEIVE0: PUSH PSW PUSH ACC CLR EX0; related external interrupt 0 ? MOV R7, TH0; read the time value MOV R6, TL0? CLR C MOV A, R6 SUBB A, # 0BBH; calculate the time difference MOV 31H, A; storage results MOV A, R7 SUBB A, # 3CH MOV 30H, A? SETB EX0; open external interrupt 0 POP ACC? POP PSW RETI Fourth, the ultrasonic ranging system software design Software is divided into two parts, the main program and interrupt service routine, shown in Figure 3 (a) (b) (c) Completion of the work of the main program is initialized, each sequence of ultrasonic transmitting and receiving Interrupt service routines from time to time to complete three of the rotation direction of ultrasonic launch, the main external interrupt service subroutine to read the value of completion time, distance calculation, the results of the output and so V CONCLUSIONS Required measuring range of 30cm ~ 200cm objects inside the plane to do a number of measurements found that the maximum error is 5cm, and good Single-chip design can be seen on the ultrasonic ranging system has a hardware structure is simple, reliable, small features such as measurement Therefore, it can be used not only for mobile robot can be used in other detection Thoughts: As for why the receiver do not have the transistor amplifier circuit, because the magnification well, CX20106 integrated amplifier, but also with automatic gain control level, magnification to 76dB, the center frequency is 38k to 40k, is exactly resonant ultrasonic sensors frequency
呵呵？这是你提的问？
Based on the communication network Direct3D visual simulation engine design and implementationtheVisual Simulation (Visual Simulation) is used to realize 3 d space information visualization technology, it has a realistic Simulation effect and convenient operation method, can well satisfy the new plane avionics system design This paper designs and realizes an Direct3D based on the communication network visual simulation First, in this paper the characteristics of the visual simulation and the programming essentials Direct3D brief analysis of selection, and expounds the main reason for the Direct3D Secondly, put forward the visual simulation software, the total design project of the simulation software program and the software module partition the working process of the analysis of the various modules, explore the main functions and the relations among And then, based on the communication network of Direct3D visual simulation is the key technology of engine are analyzed and the study, introduces solutions discrete event simulation, Direct3D resource management and animation optimization and the mouse control technology, the key technology of the Finally, this essay discusses the Direct3D based on the communication network visual simulation software realization method, and in a more complex switched communication network as an example, the visual simulation, and the performance of the program was tested
需要将题目与摘要以及关键字翻译成英文。。
电子商务专业毕业论文参考选题 电子商务环境下供应链的构建研究 客户关系管理系统与电子政务 企业采用电子交易市场研究 中国电子政务应用市场现状及需求趋势分析 电子商务时代的竞争结构分析（课题） 我国电子商务的发展及其走向 美国电子商务发展态势及政府相关政策基点 缩小数字鸿沟的国际经验及我国的政策建议 电子政务以及国外的发展情况 我国电子政务的现状与问题 网上银行安全问题与解决对策研究 我国电子商务发展存在的问题及其对策 电子商务环境下的现代物流研究 论信息技术革命条件下的网络经济 电子商务的发展及其对现代商务的促进作用 基于电子商务的信用保障措施研究 电子商务环境下消费者规避网络购物欺诈风险 互联网与战略 电子商务领域网络犯罪的对策研究 电子商务管理中的法律政策研究 论信息技术革命条件下的网络经济 基于B2B的在线交易系统的设计与实现研究 我国网络产业的制度建设探讨 网络化经济规律的新思考 透过Web站点看中美两国企业的营销理念 如何看待网络产业和网络股 物流企业如何进军电子商务 关于发展我国电子商务的对策研究 WTO条件下我国发展电子商务的对策 现代物流与电子商务中信息技术应用研究 中国电子商务的发展研究 信息时代如何增强中国企业竞争力 基于消费者信息行为的电子商务营销策略的研究 我国外贸企业电子商务发展状况及政策建议 网络审计的结构和应用中的问题 试论我国电子商务发展现状及其所面临的若干政策问题 基于Web服务的电子商务平台的研究与实现 电子商务对中国对外贸易影响问题研究 防止网络新经济时代IT人才流失的策略研究 电子商务发展特征与我国的对策取向 电子商务对未来商业的影响 电子商务合同立法研究 网上证券交易发展的主要趋势及其对我国证券市场的影响 电子商店经营模式之研究 我国电子金融业务发展现况及建议 跨国企业电子商务的策略研究 网络银行安全分析和方案设计 电子商务的交易成本分析 网络时代的企业经营与管理 企业电子商务的风险分类及其管理策略 企业采用Intranet(企业网络)之成功关键因素研究 电子商务业者之资源优势、策略优势与绩效优势关系之研究 B2B电子商务：中国企业应对策略 C2C电子商务的营销组合策略研究 基于身份的数字签名及签密技术研究 传统企业与电子商务 打造我国电子商务基础服务产业 电子商务与企业业务流程再造 电子商务企业综合评价体系研究 B2B趋势分析 资本与技术二重奏－透析B2B领先模式 新农村电子政务建设模式研究 电子商务环境下信用证收汇风险研究 基于C2C的第三方协同支付研究 基于电子商务供应链的伙伴关系管理研究 电子商务盈利模式研究 论电子商务环境下的品牌战略 基于电子商务的物流策略研究 EDI+因特网：企业电子商务的助推器 中国企业B2B的障碍 企业采用Intranet(企业网络)之成功关键因素研究 B2C企业与第三方物流企业的战略联盟
我认为楼主可以选择一些贴近生活实际的选题。这样可以联合实际，来增加论文的现实意义。比如说电子商务发展现状分析，可以分析现状，找出不足，提出对策！再比如说电子商务对提高我国金融业的价值可以写我国金融业发展现状，电子商务的概述与兴起，以及应用价值。望采纳。电子+商我务详论谈文不有会偿写服务怎么办？
多看书，多上网查！
我晕 5姐怎么还学习了？？ 家庭智能化系统, 报警主机使用说明 , 微机灯光控制系统, IC卡片介绍 ADSL 路由功能的配置
1．电子与通信工程 无线网络 光通信 多媒体通信2．网络 软件技术在通信工程 微波工程 信息通信工程3．人工智能 生物信息学 软件工程 信号处理4．嵌入式系统 编码 音频/语音信号处理 图像/视频处理和编码5．医学成像和图像分析 应用电子生物医学电子 工业电子和自动化 机器人6．电子设备在通信 电子工程 神经网络的应用 工业自动化与控制7．设备建模与仿真 VLSI设计与测试 微加工、微传感器和MEMS 光电子和光子技术8．工艺技术 纳米技术 信息技术 通信和车辆技术9．电力系统和电子 控制系统 生物医学工程 生物医学成像 10．图像处理和可视化 生物医学信号处理和分析 医疗数据存储和压缩技术 生物医学建模11．生物信息学 计算机和信息科学嵌入系统 信息工程和应用 电气工程与应用 12．控制工程和应用 通信技术与应用 服务科学 工程和应用13．生物信息学和应用 能源和交通方面的智能方法Ø 出版社：SPIE(The International Society for Optics and Photonics)光学学会Ø 检索核心：EI SCIØ 发表方法：在线投稿或EASYCHAIRØ 缩写：ICEIE2017Ø 周期：投稿后在2-3周内会有审稿结果，在会议结束后3-6个月完成论文的出版和检索Ø 合作单位：山东大学(威海)Ø 时间：2017年09月16-17日Ø 发表流程u 投稿→审稿→审核结果通过→录用通知→论文注册→注册成功→参加会议→会议完成→论文出版→论文检索→完成参考内容来源：《ICEIE2017电子与信息工程》
这个你搜下一大堆，但是不建议直接采用别人给你提供的题目，你最好是集合自己所学的内容来定题目，电子商务本身范围也是比较广的，每个学校的这个专业学习具体内容都是有差别的。如果本科毕业论文，这个你自己可以先不定题目，先写写正文，最后根据正文来定题目，你最好百度搜下：普刊学术中心，上面有很多关于论文的写作资料，多学习下，你写论文才顺利。如果是研究生的话，肯定要结合自己做的课题或者项目来写毕业论文才是正确之道
你把提问写清楚
不用写了，电子信息毕业就失业。不像人家修鞋的，还能一个月赚到1500块钱。