固定式可燃气体检测报警器运行管理中存在的问题及对策

针对固定式可燃气体检测报警器运行管理中存在的问题进行了分析,并提出整治措施.     

石油化工企业有限空间中的气体检测

介绍了便携式气体检测报警仪用于石油化工企业中有限空间的气体检测时的采样方法、检测点选择、检测工作程序以及检测结果的处理.     

电导和直流安培双检测器离子色谱法测定清洁水样中的碘化物

选用配备了2种不同检测器(电导检测器和直流安培检测器)的离子色谱仪对稀释后过0.22μm滤膜的水样进行分析。配备有直流安培检测器的离子色谱仪测定水中碘化物的方法在0.100~20.0μg/L范围内线性关系良好,相关系数(r)=0.9999,方法检出限为0.030μg/L,测定下限为0.120μg/L,样品加标回收率为95.0%~104%,相对标准偏差为1.06%~1.64%;配备有电导检测器的离子色谱仪测定水中碘化物的方法在20.0~2.00×105μg/L范围内线性关系良好,相关系数(r)=0.9995,方法检出限为2.00μg/L,测定下限为8.00μg/L,样品加标回收率为99.0%~110%,相对标准偏差为0.71%~3.12%。离子色谱-直流安培检测器法测定水中碘化物的方法准确度高、灵敏度高、精密度好,检出限相对较低,适用于测定ρ(碘化物)≤20.0μg/L的清洁水样;离子色谱-电导检测器法主要适用于测定ρ(碘化物)≥20.0μg/L的水样。     

综合管廊内火灾自动报警探测器实验研究

为了能够有效提升综合管廊内火灾自动报警系统的准确性和可靠性,本文采用火灾实体试验的方法,通过对各类型火灾自动报警探测器响应时间的情况进行分析和比较,研究综合管廊电力舱内常用探测器的性能。研究结果表明:接触式缆式线型感温火灾探测器可以较早的探测到电缆温度异常变化的现象,可用于早期预警。点型感烟探测器对烟粒子浓度较为敏感,可用于综合管廊电力舱室的空间探测。分布式光纤型感温火灾探测器对明火温度的变化较为敏感,作为空间型的火灾探测器比较可靠。     

高效液相色谱-二极管阵列检测器测定邻苯二甲酸酯色谱条件优化

采用高效液相色谱-二极管阵列检测器对6种PAEs类物质进行测定,并对梯度洗脱条件、流速、检测波长等影响化合物色谱响应的关键参数进行优化。综合考虑样品测试效率、分析精度、实际样品中存在杂质干扰等因素,确定以乙腈-水为流动相进行梯度洗脱,洗脱0~11 min流动相乙腈-水梯度比例为50∶50,11 min后流动相调整为100%乙腈,各化合物均能完全分离;色谱分析流速为0.8 m L/min;PAEs的最佳吸收波长为225 nm。在优化的色谱条件下,6种PAEs的线性良好,相关系数均大于0.999 8,仪器检出限为0.08~0.12 mg/L,保留时间、峰面积的相对标准偏差分别为0.02%~0.60%、0.13%~0.86%。方法灵敏度较高,适合土壤等邻苯二甲酸酯含量较高基质样品的快速分析。     

High serum S-equol content in red clover fed ewes: the classical endocrine disruptor is a single enantiomer

An expedient high performance liquid chromatography (HPLC) method was developed for the quantitative analysis of environmental estrogenic isoflavonoids, particularly (S)-equol, in red clover fed ewes. We report here the phytoestrogen analysis of red clover silage and the serum of ewes fed with this feed. Ewes received daily 10.5 g of formononetin on average from red clover silage. In the serum samples a major part of formononetin had been metabolised to equol (average 7.7 μg ml⁻¹). According to chiral HPLC analysis, the equol present in the serum of ewes was solely of the (S)-form. We also demonstrate the presence of the metabolite O-demethylangolensin (O-DMA) in ovine serum.     

Radon Exhalation Rate of Some Building Materials Used in Egypt

Indoor radon has been recognized as one of the health hazards for mankind. Common building materials used for construction of houses, which are considered as one of the major sources of this gas in indoor environment, have been studied for exhalation rate of radon. Non-nuclear industries, such as coal fired power plants or fertilizer production facilities, generate large amounts of waste gypsum as by-products. Compared to other building materials waste gypsum from fertilizer production facilities (phosphogypsum) shows increased rates of radon exhalation. In the present, investigation solid state alpha track detectors, CR-39 plastic detectors, were used to measure the indoor radon concentration and the radon exhalation rates from some building materials used in Egypt. The indoor radon concentration and the radon exhalation rate ranges were found to be 24–55 Bq m⁻³ and 11–223 mBq m⁻² h⁻¹, respectively. The effective dose equivalent range for the indoor was found 0.6–1.4 mSv y⁻¹. The equilibrium factor between radon and its daughters increased with the increase of relative humidity.     

Molecular cytogenetic analysis of term placentae suspected of mosaicism using fluorescence in situ hybridization

In first-trimester chorionic villus sampling (CVS) for prenatal diagnosis, abnormal chromosomal findings, such as mosaicism, trisomies, or suspect abnormal karyotypes, are found more frequently than at amniocentesis. The fact that these chromosomal abnormalities do not always reflect the fetal karyotype but may be restricted to the placenta is a major problem in diagnosis and counselling. In this paper we present the results of fluorescence in situ hybridization (FISH) studies on interphase nuclei of three term placentae investigated because of false-positive findings at first-trimester CVS. The chorionic villi of the first case showed a mosaic chromosome pattern involving a trisomy 10 cell line and a normal cell line, those of the second case a total trisomy 8 cell line, while in the third case a complete monosomy X was found. Follow-up amniocentesis in each of these three cases revealed a normal karyotype. By using FISH, we were able to confirm the presence of the aberrant cell lines, which were all confined to one part of the placenta. FISH on interphase nuclei allows the investigation of large numbers of cells for the existence of numerical chromosome aberrations in a quick and reliable way.     

荧光化学传感器的制备及其在环境分析监测中的应用

随着荧光分析技术和传感技术的发展,荧光化学传感器已经成为一种重要的连续分析测量装置.它具有很高的选择性和灵敏度,可以实现对pH、溶解氧、含氮化合物、有毒害重金属离子、有机污染物进行实时和在线测定,因此在环境分析监测方面具有广泛的应用前景.简要介绍了荧光化学传感器的原理、制备及分类,综述了近年来荧光化学传感器的发展及其在环境分析监测中的最新研究成果,并探讨了荧光化学传感器在环境分析监测领域的应用前景和发展方向.     

API MODEL 100A光路系统对二氧化硫测定值的影响

通过比较二氧化硫测定值与紫外灯强度、紫外检测器调节值及光电倍增管高压值的关系，提出二氧化硫测定值与紫外灯强度、光电倍增管高压值成正比，与紫外检测调节值成反比的结论，并对仪器校准提出了有效性建议。