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631.
基于流体力学中空气射流理论,建立气幕旋风排风罩流场的三维数学模型。影响气幕旋风排风罩效果的因素很多,主要包括:射流气动参数、吹吸气动参数以及流动空间的边界条件和装置结构等。针对不同送风速度、不同送风角度下两种情况进行分析,并利用FLUENT计算动力学软件对这两种情况下气幕旋风排风罩的流场进行了数值模拟,经过比较确定出最佳效果时的参数,并利用示综烟雾进行了实验。结果表明:所建立的气幕旋风排风罩流场的数学模型完全正确,所确定的最佳效果时的参数和实际情况基本一致,可用于工程实际。 相似文献
632.
作为国家应急预案体系的重要组成部分,生产经营单位应结合本单位的实际情况编制安全生产事故应急预案并形成体系,互相衔接。本文分析了应急预案相互衔接的重要性及其要求,按照常态和非常态两种模式提出了应急预案相互衔接的方式,可以供生产经营单位编制安全生产事故应急预案时参考。 相似文献
633.
地铁在面对各种灾害时,各类防灾及应急设施的准备是否充分将直接影响到救援工作的质量。通过实地考察北京、日本(东京地铁车站为主)及韩国釜山城市的地铁车站防灾应急设施,探讨东京和釜山地铁与北京地铁应急设施的异同,并结合我国关于大型现代地铁枢纽站应急预案的研究,针对我国地铁在防灾应急设施方面存在的问题提出改进建议。 相似文献
634.
Faezeh Ghanati Parviz Abdolmaleki Majid Vaezzadeh Elham Rajabbeigi Mohammad Yazdani 《The Environmentalist》2007,27(4):429-434
In the present research, the effects of static magnetic field, with or without iron on the growth, the activity of certain
enzymes (like polyphenol oxidase and phenyle alanine ammonialyase), the content of phenolic compounds and the essential oil
composition of sweet basil (Ocimum basilicum) were studied. Treatment of plants with static magnetic field with or without iron led to decrease of the growth of plants
as well as decrease in the activity of phenyle alanine ammonialyase and of phenolic compounds content. In addition in those
plants exposed to magnetic field the amount of essential oils, notably of methyl chavicol, was increased. Exposure of plants
to the magnetic field decreased the activity of polyphenol oxidase, whereas treatment of plants with iron when exposed to
magnetic field increased polyphenol oxidase activity. In this group the content of essential oil was reduced. 相似文献
635.
J. L. Bardasano J. Álvarez-Ude I. Gutiérrez M. Raposo R. Goya 《The Environmentalist》2007,27(4):519-523
Objectives This paper aims to provide evidence of an inductive electromagnetic bioeffect on the human brain, which is independent from
sound waves and produced by mobile phones, in proximal field, through correlating the EEG data obtained from electrodes placed
on both normal and cochlear deaf individuals.
Methods Two groups of subjects are placed under controlled electromagnetic conditions inside a Faraday chamber, 12 healthy and another
12 suffering from cochlear deafness). Each is sitting on a chair, fitted with additional support, and holding a cellular phone
2 cm away form the right auricular, in order to avoid a thermal effect as much as possible. All of them, relaxed and with
their eyes closed, are EEG recorded in a basal state with their mobile phones off. Then, each of them is again recorded under
the same conditions but with the mobile on and listening to the same conversation. In order to assess the observed EEG changes,
a statistical analysis by means of the FFT (Fast Fourier Transform) was carried out.
Results For both, healthy and cochlear deaf, assimilation or integration of the mobile phone signal by some electrodes is to be found.
This is due to the increase of amplitudes for alpha and theta waves, whereas the signal is not integrated in other electrodes.
By correlating the spectra of frequencies of corresponding EEG records for the same brain areas, we have not observed significative
differences for both groups.
Conclusions A possible electromagnetic direct inductive, non-thermal, bioeffect on the human brain is observed. This effect is produced
by the use of mobile phones and it bears no relation to the sound waves. 相似文献
636.
空间信息技术以及计算机技术的发展,给环境监控提供了先进、快速和科学的方法。其中,遥感技术由于能够快速、宏观地获得所监控区域的数据,近年来已逐渐成为环境监控系统中的重要技术手段。遥感信息是被控区域的电磁辐射能量及其结构特征与时空状态在遥感图像上的表现。今后,遥感技术、在线监控系统和地理信息系统等多种信息处理工具的结合将是环境信息监控系统发展的主要方向。 相似文献
637.
Mondher Chehata David Jasinski Michael C. Monteith William B. Samuels 《Journal of the American Water Resources Association》2007,43(3):813-828
Abstract: Data interpretation and visualization software tools with geostatistical capabilities were adapted, customized, and tested to assist the Chesapeake Bay Program in improving its water‐quality modeling protocols. Tools were required to interpolate, map, and visualize three‐dimensional (3D) water‐quality data, with the capability to determine estimation errors. Components of the software, originally developed for ground‐water modeling, were customized for application in estuaries. Additional software components were developed for retrieval, and for pre‐ and post‐ processing of data. The Chesapeake Bay Program uses the 3D mapped data for input to the Bay water‐quality model that projects the future health of the Bay and its tidal tributary system. In determining water‐quality attainment criteria, 3D kriging estimation errors are needed as a statistical measure of uncertainty. Furthermore, given the high cost of installing and operating new monitoring stations, geostatistical techniques can assist the Chesapeake Bay Program in the identification of suitable data collection locations. Following the evaluation, selection, and development of the software components phase, 3D ordinary kriging techniques with directional semi‐variograms to account for anisotropy were successfully demonstrated for mapping 3D fixed station water‐quality data, such as dissolved oxygen and salinity. Additionally, an improved delineation tool was implemented to simulate the upper and lower pycnocline boundary surfaces allowing the segregation of the interpolated 3D data into three separate zones for a better characterization of the pycnocline layer. 相似文献
638.
Daren M. Carlisle Michael R. Meador 《Journal of the American Water Resources Association》2007,43(5):1194-1207
Abstract: A predictive model (RIVPACS‐type) for benthic macroinvertebrates was constructed to assess the biological condition of 1,087 streams sampled throughout the eastern United States from 1993‐2003 as part of the U.S. Geological Survey’s National Water‐Quality Assessment Program. A subset of 338 sites was designated as reference quality, 28 of which were withheld from model calibration and used to independently evaluate model precision and accuracy. The ratio of observed (O) to expected (E) taxa richness was used as a continuous measure of biological condition, and sites with O/E values <0.8 were classified as biologically degraded. Spatiotemporal variability of O/E values was evaluated with repeated annual and within‐site samples at reference sites. Values of O/E were regressed on a measure of urbanization in three regions and compared among streams in different land‐use settings. The model accurately predicted the expected taxa at validation sites with high precision (SD = 0.11). Within‐site spatial variability in O/E values was much larger than annual and among‐site variation at reference sites and was likely caused by environmental differences among sampled reaches. Values of O/E were significantly correlated with basin road density in the Boston, Massachusetts (p < 0.001), Birmingham, Alabama (p = 0.002), and Green Bay, Wisconsin (p = 0.034) metropolitan areas, but the strength of the relations varied among regions. Urban streams were more depleted of taxa than streams in other land‐use settings, but larger networks of riparian forest appeared to mediate biological degradation. Taxa that occurred less frequently than predicted by the model were those known to be generally intolerant of a variety of anthropogenic stressors. 相似文献
639.
实现道路交通安全的营运车辆监控系统框架研究 总被引:1,自引:0,他引:1
当前营运车辆监管中,交通管理部门、运输企业和司乘人员3方没有直接的信息通道,导致监管不到位,影响道路交通安全。笔者探讨了营运车辆监控的信息传输通道;以GPS、无线通信技术和互联网为基础,设计了营运车辆监控的技术框架,实现了联系3方的信息传输通道;分析框架实现的关键技术,包括道路限速数据库,车辆超速、疲劳驾驶、超载等违法行为的判定模式等;以广东省营运车辆监控系统为例,验证了框架的可行性。该技术框架使司乘人员的交通违法行为被及时警告和提醒,交通管理部门可以及时制止交通违法行为,可以主动预防交通事故,提高道路交通安全水平。 相似文献
640.
Illinois has been operating an ambient water quality network of almost 600 stations for several years. In 1977 changes in program emphasis toward intensive monitoring, the need for improved procedures and quality control in monitoring operations, and the desire to create a single data base of all Illinois State monitoring data, resulted in a redesign of the ambient monitoring program.A unique cooperative program between the Illinois Environmental Protection Agency and the US Geological Survey provides for their monitoring a portion of the network. The Survey provides flow data at most network stations as well as extensive manpower training, equipment, data processing, and program quality control. Informal agreements with other agencies have permitted a great reduction in the monitoring effort required by the Illinois Environmental Protection Agency. 相似文献