The mass production and quality control of RPCs for the Daya Bay experiment

Resistive plate chambers will be used in the Daya Bay reactor neutrino experiment to help veto backgrounds created by cosmic-ray muons. The mass production of RPCs began in 2008 and by the end of 2009, 1600 RPCs (3500 m²) had been produced and tested. This paper describes the production and quality control procedures, and quality assurance using cosmic-ray testing.     

Thermal Radiation Calorimeter for Measuring the Specific Heat Capacity of Liquid Samples

A new thermal radiation calorimeter for measuring the specific heat capacity of liquid samples continuously in the temperature range from 280 to 360 K is described. The heat input to the sample cell from the heater by thermal radiation is estimated using the effective emissivity, which is the apparatus constant. The heat capacity of a sample can be calculated from the temperatures of the sample and the heater, and the temperature change rate of the sample. The present sample cell was made of Pyrex glass; therefore most liquid samples do not react with the sample cell, and blackening of the surface of the sample cell is not necessary in the present temperature range. The specific heat capacities for ethanol, ethylene glycol, n-heptane, n-valeric acid, and water+ethanol mixtures were measured to confirm the reliability of the present calorimeter.     

Hadron energy reconstruction for the ATLAS calorimetry in the framework of the non-parametrical method ATLAS

This paper discusses hadron energy reconstruction for the ATLAS barrel prototype combined calorimeter (consisting of a lead-liquid argon electromagnetic part and an iron-scintillator hadronic part) in the framework of the non-parametrical method. The non-parametrical method utilizes only the known e/h ratios and the electron calibration constants and does not require the determination of any parameters by a minimization technique. Thus, this technique lends itself to an easy use in a first level trigger. The reconstructed mean values of the hadron energies are within ±1% of the true values and the fractional energy resolution is

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. The value of the e/h ratio obtained for the electromagnetic compartment of the combined calorimeter is 1.74±0.04 and agrees with the prediction that e/h>1.66 for this electromagnetic calorimeter. Results of a study of the longitudinal hadronic shower development are also presented. The data have been taken in the H8 beam line of the CERN SPS using pions of energies from 10 to 300 GeV.     

GERG Project: Development and Setup of a New Combustion Reference Calorimeter for Natural Gases

Natural gas plays an important role for worldwide energy supply. For billing purposes precise metering of volume and superior calorific value are very important. At present, only a few institutions worldwide are able to determine the superior calorific value (SCV) of gases and their mixtures with an uncertainty of less than 0.2%. Calculations of SCV’s of natural gases using the data of ISO 6976 provides a similar uncertainty as experimental approaches. For this reason a GERG (Groupe Européen de Recherches Gazières) project was initiated to develop a new reference calorimeter for determining the SCV of flammable gases (natural gases), based on the principle of Rossini for a combustion calorimeter. The purpose of such a reference calorimeter is to determine the SCV of pure gases and gas mixtures with an uncertainty of less than 0.05%. The overall uncertainty budget for the SCV is mainly influenced by the mass determination and temperature measurement. An automated weighing and calibration device is used to measure the mass of the combusted gas with an experimental uncertainty of approx. 0.015%. In addition to the experiment, the flow and temperature field in the calorimeter were simulated. These simulations help to reduce each of the combined uncertainties for the combustion and calibration experiment resulting from the temperature measurement. The determination of the adiabatic temperature rise is performed analytically. The assumptions made by early investigators were carefully reconsidered for the first time. The analysis of the temperature–time curves considers (a) the method of evaluation, (b) the interval length of the main period, (c) the location of the heat release during the calibration experiment, and (d) the temperature sensor location.     

A Modernized Calorimeter for Measuring the Isobaric Heat Capacity of Hydrocarbons by a Continuous-Flow Method in the Critical Region

A method is described for the precision measurements of the isobaric heat capacity C_p of hydrocarbons of the normal series in a wide neighborhood of the critical point, characterized by anomalously high values of C_p, the presence of maxima and high temperatures, for which thermal decomposition of the products investigated is possible. Modernization of the method was undertaken in order to increase the accuracy of measurements of the absolute temperatures (the reference temperatures) and small differences in temperature (ΔT < 0.1 K) with original “ignoble” thermocouples. In order to minimize heat loss in the calorimeter and to increase the reliability of the experimental equipment, a new construction of the heat meter was developed and a metrological estimate of it was carried out. __________ Translated from Izmeritel'naya Tekhnika, No. 8, pp. 43–48, August, 2005.     

数字调制质量参数的校准和量值溯源

在数字移动通信中，描述数字调制质量的参数是一组新出现的重要参数。用实验数据证明国外仪器制造厂商给出的数字调制质量参数校准方法存在的缺陷，并研究出了新的校准方法；提出了数字调制质量参数量值溯源方案。     

数字心电图机计量发展及数字心电图标准波形评定方法

随着心电检测设备的发展,原有的计量标准已经不能全面评定其计量性能,波形一致性、波形失真度等参数正在成为新的计量检定规程和工作标准中主要考虑的内容.通过回顾数字心电图机计量法规和标准的发展,探讨了数字心电图标准波形的评定方法.结果表明,波形总失真度能够作为评定数字心电标准波形的有效参数.     

动态数字视频实时记录

:介绍一种基于计算机的数字视频实时记录系统。它可将每秒 2 5帧 ,格式为 51 2× 51 2× 8bit的图象实时地记录在 SCSI硬盘上 ,并且无信息损失 ,为事后的分析判断提供了良好的基础。     

数字化家庭图像监控系统

根据家庭安全防范的需要,设计实现了经济实用的数字化家庭图像监控系统。该系统以Windows、Java2为开发平台,以廉价的USB摄像头为图像采集设备。针对USB摄像头采集图像效果差,提出了一种快速有效的运动对象检测和分类算法,并能在异常发生时快速报警。同时利用媒体的流化技术和RTP／RTCP协议,实现了视频流的实时播放、传输和存储。     

一种数字测图中的自动曝光控制技术

数字测图可提供高质量的数字图象 ,控制好测量系统中数字相机的曝光量是获取最佳数字图象的重要因素之一。论述了如何利用自动曝光控制技术控制曝光时间获取较为理想的数字图象     

序列图象目标的一种特殊数字跟踪方法

介绍了在数,模检测相结合的电视跟踪器的一项关键技术－指寅区域的位置和大小的序列图象的实时捕获和处理,并以ＡＤＳＰ２１８１为核心实现了一实际的系统,分析了其中的关键硬件技术介绍了可编程器件ＥＰＬＤ在其中的应用,给出了实时采集处理的结果。     

一种科氏流量计的数字信号处理与驱动方法研究

数字信号处理和数字驱动是科里奥利质量流量计的发展趋势。研究了基于同步调制的数字信号处理方法，进行公式推导、性能分析和计算机仿真。研究数字驱动方法并利用数字控制方法提高流量管的起振性能，给出了数字驱动方案。     

改善数字随动系统过渡过程方法

对控制系统阶跃响应的过渡过程进行研究,提出在计算机控制系统中改善过渡过程的新方 法,把过渡过程分成不同的阶段,各个阶段的传递函数不变而初始条件变化。从仿真结果看出,利用新方法可使控制系统获得快速无纹波无超调的过渡特性。     

光纤准白光干涉信号数字化处理方法

提出一种光纤准白光干涉信号数字化处理方法。该方法采用干涉条纹脉冲实现干涉包络信 号同步采集,克服了导轨移动速度不均匀造成的影响;通过高斯函数曲线拟合方法高精度确定干涉信号零光程差点;大大提高了准白光干涉信号定位精度。为消除包络信号采样边界点不确定性带来的误差,采用外插法进行补偿。实验表明,采用该方法对光纤准白光干涉信号零光程差位置的定位精度优于0.5个干涉条纹。     

数字视频系统开发测试平台及其实现

报告了自主研制的基于ＰＣ计算机ＰＣＩ总线的数字视频产品的开发测试平台。该系统以其功能强、通用性好、便于扩充、使用方便等伏良性能已成功地应用在高清晰度电视（ＨＤＴＶ）信源解码器的演示、视频编码器和复用器的研制以及标准清晰度数字电视（ＳＤＴＶ）的开发过程中,具有广阔的应用前景。     

基于数字相关原理的相位差测量新方法

提出了一种基于数字相关原理的相位差测量新方法,该方法直接对两被测信号作互相关运算,并利用相关和正弦函数的一些性质,使部分噪声分量被有效地与有用信号相分离,从而提高了抗随机干扰能力和测量的准确度。理论分析和数字仿真结果表明：该方法具有不必预先知识正弦信号频率、抗随机干扰能力强等特点;其测量准确度和信号的信噪比和数据采集卡的位数有关,可通过调节总采样样本点数减小它们的影响。     

数字影像证据的防伪技术研究及相关系统的建立

本文研究数字影像证据的防伪技术,提出了一种基于Lab色彩空间模板的盲水印算法,并建立了相关的数字影像防伪系统,为维护数字影像证据的公信力提供了一种有效的技术方案,并在司法实践中得到了成功应用。     

非ARMA随机信号谱估计的数字滤波算法及性能分析

为克服传统的周期图谱估计方法存在的分辨率低及非一致估计等缺点而迅速发展的各种近代谱估计法只能适用于ＡＲＭＡ（Ａｕｔｏｒｅｇｒｅｓｓｉｖｅ－ｍｏｖｉｎｇａｖｅｒａｇｅ）信号的谱估计。为解决存在于各种物理过程中的非ＡＲＭＡ随机过程（包括１／ｆ过程）的谱估计，本文提出了一种对非ＡＲＭＡ随机信号的非递归数字滤波算法，重点研究了算法主要参数（滤波器长度、数据长度）的选择原则及对谱估计准确度和精度的影响。理论分析及实际测量证明，此方法具有分辨率高、谱估计精确较好及一致估计等优点，特别适用于对非ＡＲＭＡ信号的某些特征频率点的谱估计。     

射线数字成像检测仪的光电系统设计

设计了射线数字成像检测仪的光电系统,包括转换屏、光路、CCD相机以及计算机处理电 路等。采用CsI(Tl)单晶闪烁体将X射线图像转换为可见光图像,用科学级CCD将光图像转换为电信号,利用计算机并行口对图像进行采集. 实验结果证明图像质量优于像增强器组成的成像系统,适用于要求高质量成像检测的场合。     

非线性系统响应计算的一种数字模拟方法

目前,对单自由度非线性振子受随机激励的响应计算已经发展到了多种方法。本文从白噪音与泊松过程的联系出发,把系统受白噪音或调制白噪音激励的响应计算转换为对泊松随机脉冲激励的响应计算,从而发展了一种数字模拟方法。此法与其它模拟计算方法所得结果有良好的一致性,并具有较高的计算效率。