Research of Micro-mass Measurement System Based on Vibrating Cylinder Sensor

近几年来国内对高精度的微质量测量仪器需求逐渐增加，它广泛用于化学、生物、表面处理等诸多领域，既可用于科研院所和企业的研究工作，也可用于学校科学的工作，设计的领域进行各类研究的工作 而其两类产品---电子天平和谐振式微质量传感器---都被被国外产品垄断，价格高昂。电子天平系列精度不够高，而且不能测量物体粘弹性；谐振式（QCM）精度高，但价格昂贵，而其关键技术都受到专利保护，国内研究较少。基于以上因素，课题组另辟蹊径，将国内已经研究得较深入的谐振筒传感器引入，用于测量微质量领域。本论文主要做了一下内容： 收集有关振筒传感器的资料，进行进一步的分析。 设计了一块基于CPLD的双通道同步高速高位...Recently, the demand for high precision micro-mass instruments measurement is increasing gradually. They are widely used in fields like chemistry, biology and facial disposal. There are two kinds of products in micro-mass measurement fields—the electronic scale and resonant micro-mass measurement instrument and they practically dominate the whole market. The precision of electronic scale is not ...学位：工学硕士院系专业：物理与机电工程学院机电工程系_测试计量技术及仪器学号：1992006115187

Research on pipeline control method based on VHDL

本文将乒乓操作的控制方法应用于双通道频率/数字的数据采集中,介绍了这种逻辑结构的设计。重点论述了在VHDL中,如何通过脉冲信号边沿(上升沿或下降沿)的脉冲化,信号延迟分析和初始值保持等方法来实现这种由双沿信号产生的逻辑控制信号的方法。这样就解决了在VHDL一个PROCESS过程语句中不能实现双沿判断的缺点。这种控制方法延时小,整个过程的动作衔接紧密,自动化程度较高。同时,可以通过提高采集时钟CLK的频率来进一步减小延时。本方法在QUARTERSⅱ5.1软件中通过时序仿真,并下载到cycloneⅱ芯片中验证,完全能满足设计的要求。This paper discusses a kind of method that how to applies the pipeline technology to data acquisition in double channel Frequency /Data conversion.The design of this logic structure is described.Moreover,emphases are put on the details that how the signal for control is generated by means of converting either edge of the pulse into a pulse,analyzing the delay of the signal and holding the original value.So,the defect that the double edge can't be sprung together in a PROCESS in VHDL could be solved,and the delay of this control method can be limited to a very small value.With this kind of logic control,the behavior goes smoothly without stop.This design has been successfully simulated in QUARTERSⅱ 5.1 and tested in cycloneⅱchip.福建省重大专项前期研究计划资助项目(2005HZ1022

Windowed narrow band signal processing system in optical fiber current sensor

针对光纤电流传感器由于环境因素的变化，从而导致传感器输出信号噪声较大的问题，提出了一个基于频域窄带加窗理论的信号处理系统。文中详细描述了频域窄带加窗算法的特性，并对其进行了Ｆｏｕｒｉｅｒ分析。该系统能实现１Ｈｚ的窄带滤波，实验中对普通光纤电流传感器的采集数据进行了窄带加窗信号处理，结果表明该系统能够有效地提高光纤电流传感器的输出信噪比。The output of optical fiber current sensor may be suffered from variation of ambient perturbations. A novel signal processing system based on the theory of windowed narrow band function is proposed in this paper for current detection. Both the function's property and analysis based on Fourier transform are discussed in details. The system can achieve 1Hz bandwidth. Results of experience show that the system can enhance the signal-to-noise ratio of OFCS efficiently

Experimental investigation in isolation degree polarization sensitivity of optical fiber isolator

采用了 1 80°输入测量的新方法研究了光纤隔离器隔离度随着输入线偏振光偏振方向变化。并对其进行了详细的讨论与分析。研究的结果对于该类光纤隔离器的设计和测试具有一定的参考价值A new method for omnidirectional inputs′ measurement of isolation degree of optical fiber isolator is presented.The results of experiment show that isolation degree changed according to the variation of polarization direction of input linear polarization light.The rationale is analyzed in details.The results are valuable for design and measurement of this type optical fiber isolators

Remote Current Detection System Employing Polarization-Maintaining Fiber Current Sensor

针对传统光纤电流传感器不能进行远程检测缺点 ,提出一种基于保偏光纤的电流传感器远程检测系统 ,并对其设计原理进行了详细的分析和讨论。实验表明 ,该套系统能从根本上解决光纤电流传感器的远程检测应用问题 ,能够准确有效地进行高强电流的远程实时检测The traditional optical fiber current sensor can not take remote current detection. A novel remote current measurement system employing polarization maintaining fiber current sensor is proposed and demonstrated in this paper. The working principles and features of this system are analyzed in details. Experimental results show that this system works accurately in detection. The problem that optical fiber current sensor cannot be using for remote detection is resolved successfully

Analysis and design of optical fiber current sensor based on DSP

在传统光纤电流传感基础上提出了一种新型基于DSP(digitalsignalprocessor)的光纤电流传感器设计方式 ,并对其工作原理及特性进行了详细的分析和讨论。这种基于DSP的光纤电流传感器为高强电流的测量提供一种新的途径A novel optical fiber current sensor based on DSP is described. This technique is based on traditional optical fiber current sensor rationale. The working principles and features at this sensor are analyzed in details. It provides a new approach for large current measurement

on the policy and algorithm to block instant messaging

本文根据即时通讯（IM）的协议模型，在TCP层和即时通讯协议层分析了阻断即时通讯的可能性，分别提出了基于TCP层和即时通讯协议层的协议分析的阻断策略．在TCP层，通过插入FIN报文或RST报文，以关闭TCP连接（特别是与登录服务器的连接）；在即时通讯协议层，通过对相应字段的值进行设置，使客户端进入不活动状态．为使阻断策略能够有效地实施，本文也提出了一个消息驱动的实现算法．通过对Yahoo! Messenger的阻断实验，证明了本文提出的方法能够高效地完成阻断任务（平均数据包量不超过2．5个）．用统计分析的方法对它们的性能进行比较，结果表明各种方法的效率在不同的背景流量下没有显著的差异，通过消息驱动算法实现的基于协议分析的阻断策略，其工作效率不受背景流量的影响．另外，即时通讯数据的触发方式，使得发送的阻断包的数量与背景流量无关，也不对网络负载造成明显的影响．本文的工作为实施即时通讯的阻断提供了有效的解决方案

Experimental Investigation in Isolation Degree Polarization Sensitivity of Fiber Optic Isolator

本文采用了 180°输入测量的新方法研究了光纤隔离器隔离度随着输入线偏振光偏振方向变化。并对其进行了详细的讨论与分析。研究的结果对于该类光纤隔离器的设计和测试具有一定的参考价值。A new method for omnidirectional inputs’ measurement of isolation degree of fiber optic isolator is presented. The results of experiment show that isolation degree changed according to the variation of polarization direction of input linear polarization light. The rationale is analyzed in details. The results are valuable for the design and measurement of this type of fiber optic isolators

Experimental Investigation in Isolation Degree Polarization Sensitivity of Fiber Optic Isolator

本文采用了 1 80°输入测量的新方法研究了光纤隔离器隔离度随着输入线偏振光偏振方向变化。并对其进行了详细的讨论与分析。研究的结果对于该类光纤隔离器的设计和测试具有一定的参考价值A new method for monidirectional inputs′ measurement of isolation degree of fiber optic isolator is presented. The results of experiment show that isolation degree changed according to the variation of polarization direction of input linear polarization light. The rationale is analyzed in details. The results are valuable for design and measurement of this type fiber optic isolators