超声波—文丘里渠流量测量系统的应用

明渠液体流量测量，离不开流量测量系统。随着对工业污染源监督监测力度的加强，在线监测要求的力度也在不断提高，促成对水质监测仪器及相关自动化控制所需各种测量技术、自动化仪器仪表技术的开发应用，发展与完善了许多应用技术。工业污水处理工程的管理、操作及控制，使用可靠、坚固、维护方便的仪表监控及数据采集系统已成为在线监测采用设备的首选要求，在各项污染监测指标中，流量的测量为最基本的测量参数，其重要性在总量控制要求不断加强的今天是不言而喻的。自由排水的文丘里渠，结构简单，它易于安装无磨损可以实现免维护，并且…     

Response of CH4 emission of paddy fields to land management practices at a microcosmic cultivation scale in China

The terrestrial ecosystem may be either a source or a sink of CH4 in rice paddies, depending, to a great extent, on the change of ecosystem types and land use patterns. CH4 emission fluxes from paddy fields under 4 cultivation patterns (conventional plain culture of rice(T1), no-tillage and ridge culture of rice(T2), no-tillage and ridge culture of rice and wheat (T3), and rice-wheat rotation(T4)) were measured with the closed chamber technique in 1996 and 1998 in Chongqing, China. The results showed that differences existed in CH4 emission from paddy fields under these land management practices. In 1996 and 1998, CH4 emission was 71.48% and 78.82% (T2), 65.93% and 57.18% (T3), and 61.53% and 34.22% (T4) of that in T1 during the rice growing season. During the non-rice growing season, CH4 emission from rice fields was 76.23% in T2 and 38.69% in T]. The accumulated annual CH, emission in T2, T3 and T4 in 1996 decreased by 33.53%, 63.30% and 65.?3%, respectively, as compared with that in TI. In 1998. the accumulated annual CH4 emission in T], T2, T3 and T4 was 116.96g/m^2, 68.44g/m^2, 19.70g/ms and 11.80g/m^2, respectively. Changes in soil physical and chemical properties, in thermal and moisture conditions in the soil and in rice plant growth induced by different land use patterns were the dominant causes for the difference in CH4 emission observed. The relative contribution of various influencing factors to CH, emission from paddy fields differed significantly under different land use patterns. However, the general trend was that chlorophyll content in rice leaves, air temperature and temperature at the 5 cm soil layer play a major role in CH4 emission from paddy fields and the effects of illumination, relative humidity and water layer depth in the paddy field and CH4 concentration in the crop canopy were relatively non-significant. Such conservative land use patterns as no-tillage and ridge culture of rice with or without rotation with wheat are thought to be beneficial to reducing CH4 emission from paddy fields and are, therefore, recommended as a significant solution to the problems of global(climatic) change.     

测量不确定度分析的实践与体会

结合广州市环境监测中心站实验室认可工作，讨论了测量不确定度分析的方法及应注意的问题，并以高氯酸－硫酸酸溶法测定土壤全磷的不确定度分析为例，对测量不确定度进行了具体的分析。     

城市区域环境噪声测量中的几个问题

城市区域环境噪声测量中存在时间段、测点位置、标准执行区类不明确等问题，建议由当地政府依据地的实际情况划分确切的测量时间段和适用的区域环境噪声标准类别。     

秦皇岛港煤堆场防风网风洞试验研究

介绍了秦皇岛港煤堆场防风网模型风洞试验的目的，方法和内容，提供了试验结果分析。试验结果表明，煤堆场防风网可以有效地降低堆场部分区域内的风速和紊流度，减少环境污染。     

用电磁流量计测量工业废水排放量

<正> 工业废水排放量的测量,是环境管理和污染治理的基础工作,是环境保护规划和污染治理计划的重要依据,其测定数据的准确与否,是实现排放水污染物总量控制和实施排污许可证制度的关键.长期以来,工业废水排放最多根据工业用水总量估算、用自制     

用频谱分析仪进行电磁干扰测量

在新产品整个研制过程中,始终存在着EMI(电磁干扰)测试问题,频谱分析仪是能胜任这一工作的简单而灵活的设备,它能独立地进行EMI诊断测试;如果外加几个附件,它就具有完整的EMI接收机功能,可用于产品的兼容性测试。     

推广使用新型注水流量仪表

江汉石油管理局针对油田进入中高含水阶段,开发研制了先进实用的新型注水流量测量仪表。本文详述了仪表的结构原理、技术性能、安装标定、现场使用概况等。此仪表设计新颖、性能指标先进、使用范围广、操作管理方便,有可能取代老式的注水流量计量仪表而被纳入工程设计应用之中。