Model1027连续测氡仪测量室内氡浓度若干问题的探讨

本文探讨Model 10 2 7连续测氡仪测量室内氡浓度的方法。用两台仪器对一房间内氡浓度在不同情况下进行近一个月的测量后 ,得出以下结论 :仪器操作简便 ,测量结果稳定 ;仪器处于DISABLE(数字显示关闭 )状态所测氡浓度高于ENABLE(数字显示开启 )状态测量氡浓度 ;测量结果表达方式有两类 ,即氡浓度总平均值和美国环保局推荐平均值 ,多点比较测量应采用同一类氡浓度 ;仪器连续测量时间不得少于 2 4h ,最好为 4 8h或更长 ;本次所测房间氡浓度平均值为 92 5Bq/m3,符合国家标准     

差动调频式数字测微仪

电感(包括自感和互感)式测微仪是应用较多、产量较大的测微仪,瑞士TESA 公司产的351型、成都量具刃具厂产的DYJ 型和中原量仪厂产的DGS 型测微仪。此类仪器由于电感传感器具有积分效应,其输出阻抗低,电路中采用相敏检波等,可以达到高精度和高分辨率。但它采用调幅原理,抗干扰能力低,稳定性差;电路是模拟式的,如要实现数字化还需加装A/D 变换器。另一类测微仪采用调频原理,如DWY 型电容式测微仪、WFC 型涡流测微仪,有较强的抗干扰能力,但仍是模拟电路,其鉴频电路和传感器都是单相的、非线性的,仪器的稳定性和精度受到限制。     

基于长光栅旋转测角法的水平测倾仪

理论与实验表明 ,小角度的测量可通过长光栅旋转来实现。建立在傅立叶光学理论基础上的分析与实验结果是一致的。采用本方法制成的精密水平测倾仪 ,其测量范围为± 30′,测量精度为± 1″,最小分辨率为 0 .1″,仪器具有绝对零点 ,示值稳定性为± 0 .3″,为研制高精度、大量程的水平测角仪器进行了有益的探索。     

西格玛光度测尘仪全电路分析

随着对矽肺病研究及对环境污染治理的重视与发展,国内外各种呼吸性粉尘和连续粉尘采样方法几乎同时出现,相继开发了多种方式的粉尘采样器。光学快速测尘法及仪器尤被重视,而得到快速发展。瑞士生产的测尘仪传感器采用对光灵敏度极高的光电信增管器件,每立方米大气中,即使对于10μg那样微量的粉尘量也十分敏感。因此,不论是在高或低浓度的粉尘环境中测量,都能得到正确的测量值。本文对西格玛光度测尘仪作全电路分析。     

基于MSP430F149的低功耗测树仪

为了解决目前国内树木的测量工具都依靠人工手动测量,且无法对树木的直径进行长期连续观测和自动记录的问题,设计了一种以MSP430F149芯片为核心的低功耗测树仪.对整个系统的软硬件实现进行了详细阐述,同时对系统功耗进行了估算及测试.该测树仪采用2节1.5 V电池供电,能够连续记录直径生长量,并提供了方便地数据采集接口,只要插入SD卡便可自动读取数据.研究结果表明,该测树仪具有结构简单、操作方便、数据自动记录与自动存储、低功耗、低成本等优点,具有较强的实用性.     

加工中心测头的校正

在加工中心上加工工件时,测量刀具直径、长度以及确定工件零点坐标等需占用大量辅助工时,缩短这部分辅助工时对生产效率的提高具有重要意义。为此,我厂在引进辛辛那提公司四轴加工中心的同时,选购了雷尼绍(Ｒｅｎｉｓｈａｗ)公司的ＴＳ27Ｒ型刀具测头和ＭＰ12型主轴测头。刀具测头可快速测量刀具的长度和直径,并将测量值自动输入机床控制系统的刀具表中。主轴测头可准确测量工件表面位置坐标、外角和内角点位置坐标、圆柱中心线、两平行平面的中心面位置坐标,并建立工件零点与程序零点的对应关系。这两种测头操作简便,测量准确。但因两种测…     

浅谈电子测风经纬仪使用与保养技术

GYR1型电子测风经纬仪是新型的高空测风备份仪器之一。是利用光、机、电一体化技术设计开发智能化、适用面广的数字测风经纬仪系统,相比普通70-Ⅰ型测风经纬仪,它克服了手工记录观测数据、手工录入等一系列不足,只需在高空风测量时人工跟踪测风气球,系统便会自动采集测风数据、自动计算测风结果。本文介绍了GYR1型电子测风经纬仪的结构、性能、工作原理和它的使用与保养技术。     

高性能价格比多极旋转变压器单片机测角系统

抗干扰性、抗温漂等是多极旋转变压器数字测角系统的基本要求。本文提出的多极旋转变压器单片机数字式测角系统,采用晶振和EPROM等数字化技术来提高抗温漂和抗干扰能力;采用二分频等技术对基频分量作了处理,提高了测量精度;采用相位微调技术保证了激磁电源相位的正交性。采用该原理的多极旋转变压器数字测角系统具有线路简单,直流电源电压可在较大范围内波动,抗干扰性强等特点。经鉴定专家组和用户共同测试表明:该系统在60℃下无温度漂移误差、无重复定位误差且测量精度为均方根值0.0066°。已成功地应用于工业机器人、电视卫星接收站、大型卫星通讯地球站、军舰搜索雷达稳定平台上。     

测微仪测头临界脱离频率的研究

通过对电感测微仪测头运动模型的建立,对接触式动态测量时测头与工件的临界脱离频率进行了理论分析,并通过试验数据验证了理论推导的正确性。     

YP02型叶片测量仪的理论数据处理方法

YPO2型叶片测量仪是我公司最新研制的汽轮机叶片型线专用自动测量仪。如图1所示,该测量仪采用四坐标结构,其测量原理是：被测叶片在围绕固定回转轴转动的同时,三维触发测头在不同截面内按理论型线位置触测叶片表面,计算机将实际测量出的叶片型线数据与叶片型线理论数据在同一坐标系下进行对比,从而计算出叶片型线的偏差。     

A novel algorithm for quick and continuous tracing the change of radon concentration in environment

Several measurements of the radon concentration are performed by RAD7 in the University of South China. We find that 30-40 min is needed for RAD7 for tracing the concentration of the standard radon chamber. There are two reasons. The first is that the sufficient time of air cycle is needed for the radon concentration in internal cell of RAD7 equal to that of the environment; and the second is that the sufficient decay time is needed for the (218)Po concentration in internal cell of RAD7 equal to that of the radon. We used a zeroth order approximation to describe the evolution of the environment radon concentration, and obtained a novel algorithm for quick and continuous tracing the change of radon concentration. The corrected radon concentration obtained through this method is in good agreement with the reference value. This method can be applied to develop and improve the instruments for tracing the change of radon concentration quickly.     

Continuous radon concentration monitoring

The use of ionization chambers to continuously monitor the concentration of radon dissolved in ground water is described. In one case, air is bubbled through the water sample to strip the radon into the chamber. In a second operating mode, the sample water itself is flowed through the chamber. Support electronics systems are described for remote and urban applications.     

基于LabWindows/CVI的氡室测控系统设计

针对目前氡室测控系统存在的问题,提出了基于LabWindows/CVI的氡室测控系统设计方案,运用虚拟仪器本身提供的库函数、数据库技术,实现了氡室重要参数的全程实时控制.该系统具有显示直观、反应迅速、性价比优等特点,有一定的应用前景.     

Development and application of a continuous measurement system for radon exhalation rate

A continuous measurement system, with a ventilation-type accumulation chamber, was developed for radon exhalation rate determination. A reasonable sampling flow rate for the measurement system was determined by comparing the values obtained by the system with those obtained by a grab sampling method. The sampling flow rate of passage through the scintillation cell from the accumulation chamber was varied from 0.05 to 2.0 l min(-1). The difference in pressure between the inside and outside of the accumulation chamber increased as the sampling flow rate became large, and the estimated radon exhalation rate also increased with the sampling flow rate. From these results, a reasonable sampling flow rate was estimated to be less than 0.2 l min(-1).     

Continuous measurements of bronchial exposure induced by radon decay products during inhalation

The deposition of radon decay products is not equal in each of the respiratory regions and as the presence of radon has been linked with an increase in lung cancer risk, it is important to calculate the deposition of radon decay products in each of the respiratory regions. Recently, many studies on the deposition of radon in respiratory regions have been simulated using wire screens. The systems and equipment used in those studies are not suitable for field measurements as their dimensions are relatively massive, nor can they measure continuously. We developed a continuous bronchial dosimeter (CBD) which is suitable for field measurements. It was designed with specifications that allow it to be remain compact. The CBD simulates the deposition of radon decay products in the different respiratory regions by the use of a combination of wire screens. Deposition in the simulated regions of the lung can be continuously estimated in various environments. The ratio of activities deposited in a simulated nasal cavity (N) and tracheobronchial (TB) regions was calculated from the results of simultaneous measurements using CBD-R (reference), CBD-N (nasal), and CBD-TB (tracheobronchial) measurement units. After aerosols were injected into the radon chamber, the ratio of N and TB depositions decreased. This results indicate that the CBD gave a good response to changes in the environment. It was found that the ratio of N and TB deposition also varied with time in each actual environment.     

建筑内氡气来源及其通风防治方法

主要分析了建筑内氡气的来源及影响因素，并根据已有数据提出相应的通风防治方法，这对工程设计人员有实际参考价值。     

测氡仪器概述

介绍近年来测氡仪器在找矿(放射性铀钍矿、石油)、地震预报以及环境保护特别是室内氡的测定与防治方面日益显示出重要性的现状,综合介绍了目前国内外测氡仪器的原理、分类、应用,以及近年来氡气测定仪器的发展。对几种常用的瞬时法测氡仪做了重点介绍。对国际“氡热”最为流行的SSNTD方法做了较详细的叙述。     

Monitoring of indoor radon pollution

In this work the relation among building materials, insulation systems, and indoor radon pollution is evaluated. The work is part of a larger monitoring in progress in the Calabria Region (Southern Italy).The area under investigation is San Giovanni in Fiore (CS) located in the Sila upland plain. An annual monitoring is carried out in many buildings of the Sila area, with reference to their different building materials. The relationship between age of buildings and radon concentration is also considered.Nuclear tracks detector has been used (SSNTD, Solid State Nuclear Track Detector). Obtained results underline that the buildings realized with the local granite rock have greater indoor radon concentrations.The local granitic rocks, representative of the geologic area, have been analyzed by gamma spectrometry constituted by Canberra system HPGe fixed detector cooled by liquid nitrogen high radio-emission values of standard radionuclides as ²²⁶Ra, ²³²Th and ⁴⁰K.     

Automatic radon counter for continual unattended operation

An improved portable radon sampler is described which is capable of sampling and measuring atmospheric radon concentrations at repetition rates of up to five samples per hour, with sensitivities down to 0.1 pCi m(-3). The sampler and sensor can be located remotely from the counter and readout devices. The digital output of the unit is available to a printer, a digital recorder, and a computer, and a rate-meter type output is observable in real time and recorded on a strip chart.. This instrument has operated throughout full gale conditions at sea and for up to two weeks without maintenance.