基于视频识别的直接作业环节安全管控

概述了石化行业现场直接作业环节的安全管控现状,分析了现场管控过程中存在的问题。考虑现场安全管理和监督监控的实际需要,设计了石化行业直接作业现场智能化管控系统,并深入研究作业现场违章行为图像识别的关键技术。现场应用表明,系统充分体现了日常管理、实时监控、智能报警、统计分析等方面的便利性和有效性,各类违章行为图像识别准确率达到80%以上,具有一定的推广价值。     

Residual risk for cytogenetic abnormalities after prenatal diagnosis by interphase fluorescence in situ hybridization (FISH)

Results from conventional cytogenetic studies on 21 609 amniotic fluid specimens were analyzed retrospectively to determine the residual risk for a cytogenetic abnormality if interphase FISH, capable of only detecting aneuploidy for chromosomes 13, 18, 21, X and Y, was performed and did not reveal an abnormality. Detection rates (the probability of detecting a cytogenetic abnormality when an abnormality is present) and residual risks (the likelihood of a cytogenetic abnormality, in view of normal interphase FISH results) were calculated for the four major clinical indications for prenatal diagnosis (advanced maternal age, abnormal maternal serum screen indicating increased risk for trisomy 18 or trisomy 21, abnormal maternal serum screen indicating increased risk for neural tube defects and ultrasound abnormality). Differences in detection rates were observed to depend on clinical indication and presence or absence of ultrasound abnormalities. The detection rate ranged from 18.2 to 82.6% depending on the clinical indication. The detection rates of abnormalities significant to the pregnancy being evaluated (i.e. abnormalities excluding familial balanced rearrangements and familial markers) were between 28.6 and 86.4%. The presence of ultrasound abnormalities increased the detection rate from 72.2 to 92.5% for advanced maternal age and from 78.6 to 91.3% for abnormal maternal serum screen, indicating increased risk for trisomy 18 or trisomy 21. With regard to residual risk, the risk for a clinically significant abnormality decreased from 0.9–10.1%, prior to the interphase FISH assay, to a residual risk of 0.6–1.5% following a normal interphase FISH result in the 4 groups studied. Providing patients with detection rates and residual risks, most relevant to their situation (clinical indication and presence or absence of ultrasound abnormality) during counseling, could help them better understand the advantages and limitations of interphase FISH in their prenatal diagnostic evaluation. Copyright © 2003 John Wiley & Sons, Ltd.     

Hunting in unfamiliar space: echolocation in the Indian false vampire bat, Megaderma lyra, when gleaning prey

The literature suggests that in familiar laboratory settings, Indian false vampire bats (Megaderma lyra, family Megadermatidae) locate terrestrial prey with and without emitting echolocation calls in the dark and cease echolocating when simulated moonlit conditions presumably allow the use of vision. More recent laboratory-based research suggests that M. lyra uses echolocation throughout attacks but at emission rates much lower than those of other gleaning bats. We present data from wild-caught bats hunting for and capturing prey in unfamiliar conditions mimicking natural situations. By varying light level and substrate complexity we demonstrated that hunting M. lyra always emit echolocation calls and that emission patterns are the same regardless of light/substrate condition and similar to those of other wild-caught gleaning bats. Therefore, echoic information appears necessary for this species when hunting in unfamiliar situations, while, in the context of past research, echolocation may be supplanted by vision, spatial memory or both in familiar spaces.Communicated by T. Czeschlik     

水环境中重金属检测方法研究进展

重金属污染是水污染的主要问题之一,严重威胁水生生物的生存和人类健康。文章对近年来水环境中重金属的检测方法进行了综述,主要介绍了原子吸收光谱法、电感藕合等离子体法、原子荧光光谱法、溶出伏安法、生物酶抑制法、免疫分析法和生物化学传感器法等。列举了不同方法的灵敏度、准确性和适用范围等,并对各自优点进行了比较。     

一种新型"Turn-on"荧光探针用于硫化氢可视化检测

硫化氢(H2S)是表征水体污染的重要参数之一,对其进行快速、有效地检测十分重要.荧光检测法由于具有不可比拟的优势得到了广泛的关注.以2-(2'-羟基苯基)苯并咪唑为荧光团,基于H2S的亲核性,设计合成了一种新型检测H2S的荧光探针.该探针与H2S作用后,荧光强度随H2S浓度的增加逐渐增强,颜色由淡黄色变成紫色,因此能够进行可视化检测,可视化检测限为3μmol·L-1.探针的最佳激发/发射波长为320/460 nm,对H2S表现出了良好的选择性和很快的响应速度(5 min),在较宽的p H(6~9)范围内,仍然表现出较好的荧光性能,荧光检测限为6μmol·L-1.该探针为H2S的检测提供了新方法.     

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.     

苯并噻吩脱硫菌株的筛选及脱硫活性研究

从孤岛油田油浸土样中筛选到1株能降解苯并噻吩(BT)的脱硫菌,经初步鉴定该菌为戈登氏菌属(Gordona sp.).实验证明:该菌能以类似于4S途径脱除BT及其衍生物中的硫,但是不能脱除二苯并噻吩(DBT)及其衍生物中的硫.GC-MS分析表明该途径的终产物为邻羟基苯乙醛或其异构体苯并呋喃.在以BT为唯一硫源的培养基中30℃培养48h,Gordona sp.C-6能降解0.15mmol/L的BT,终产物占发酵培养基中BT加入量的50%,其余BT在有氧培养过程中挥发.通过Matlab拟合曲线确定以邻羟基苯乙酸为标准品进行产物定量检测的方法.     

Pipeline leakage detection and isolation: An integrated approach of statistical and wavelet feature extraction with multi-layer perceptron neural network (MLPNN)

Leakage diagnosis of hydrocarbon pipelines can prevent environmental and financial losses. This work proposes a novel method that not only detects the occurrence of a leakage fault, but also suggests its location and severity. The OLGA software is employed to provide the pipeline inlet pressure and outlet flow rates as the training data for the Fault Detection and Isolation (FDI) system. The FDI system is comprised of a Multi-Layer Perceptron Neural Network (MLPNN) classifier with various feature extraction methods including the statistical techniques, wavelet transform, and a fusion of both methods. Once different leakage scenarios are considered and the preprocessing methods are done, the proposed FDI system is applied to a 20-km pipeline in southern Iran (Goldkari-Binak pipeline) and a promising severity and location detectability (a correct classification rate of 92%) and a low False Alarm Rate (FAR) were achieved.