An Approach for the Aggregation of Aerodynamic Surface Parameters in Calculating the Turbulent Fluxes over Heterogeneous Surfaces in Atmospheric Models

Experimental evidence indicates that there is a significant departure of the wind profile above the underlying surface consisting of patches of solid and liquid parts, and plant communities with different morphological from that predicted by the logarithmic relationship, which gives the values larger than those observed. This situation can seriously affect the transfer of momentum, heat and water vapor from the surface fluxes into the atmosphere.The object of this paper is to generalize the calculation of the exchange of momentum between the atmosphere and a very heterogeneous surface, find a general equation for the wind speed profile in a roughness sublayer under neutral conditions, and, then, derive aggregated roughness length and displacement height over the grid cell. The suggested expression for the wind profile is compared with some earlier approaches, using a common parameterization of aerodynamic parameters over the grid cell, and the observations obtained at an experimental site in Philadelphia, PA.     

Geochemical and Geophysical Monitoring of Salinewater Intrusion in Korean Paddy Fields

The saline water intruded zone in paddy fields near the seashore can be diagnosed accurately by joint exploration with geophysical and geochemical methods. Using the electromagnetic (EM) sounding technique, the weakly consolidated zone which introduces saline water into such an area of near seashore paddy fields in Korea was detected from the variation of electrical conductivity distribution following field irrigation. Vertical electrical sounding (VES) with Schlumberger array and chemical analysis of top soils, and groundwater in the study area verified the intruded zone near the surface. The VES results showed that the intrusion of seawater occurred in the form of a channel down to 30 m below sea level. Geochemical analysis of the top soil samples for the six major elements found in seawater indicated that the region showing high concentrations is concordant with the weakly consolidated zone near the surface. The degree of contamination in the study area was investigated by comparing the soil data with those from a nearby old reclamation field. If remediation work is not done for this intrusion zone, the sodicity degree in the paddy soil is expected to increase compared with the reference site data.     

移动通讯发射基站功率密度对辐射环境影响分析

采用理论预测和实际测量的方法,对辽宁省移动通信有限公司的发射基站的电磁辐射对周边环境的影响做出预测并实际测量了场强,测算出污染半径及范围,为环境管理提供了技术支持。     

雨水口径流流量计量方法的研究及应用

针对雨水口及其他跌落水流的流量测量问题,提出一种基于动量变化率而测定来流冲击力的计量流量的方法。具体步骤是通过力传感装置和称重变送器将下落水流冲击力转化为电压信号,依据率定实验过程中电压值的变化,最终换算成雨水口径流流量。结果表明,应用该计量方法进行雨水口流量测量,其获得的流量精度较高,适应雨水口的流量变化,是一种计量雨水口流量的有效方法。     

苍山5.2级地震前电磁辐射异常

利用枣庄电磁信息台ＤＰＪ Ⅲ、ＵＬＦ Ⅲ及ＪＤ ０３型电磁辐射仪观测到的资料，分析了山东苍山５．２级地震前多数台站记录到的异常信息及其特征。     

电磁辐射对环境的污染及防护措施

电磁辐射对环境的污染已引起人们的重视 ,早在 196 9就被联合国人类环境会议列为必须严格控制的现代公害之一。论述了电磁辐射的来源、危害及减少电磁辐射是对环境污染的防护措施。对全面了解电磁辐射对环境造成的污染及危害 ,提高自我防护意识具有参考价值     

Electromagnetic Action of Heavy-Current Equipment Operating With Power Frequency

The paper presents an analysis of the effect of magnetic fields of power frequency generated by heavy-current electric equipment on the environment. The results of computation and measurements of the magnetic field in the vicinity of power busducts are included. Possible hazards are considered that result from the effects of the magnetic field on workers present in the vicinity of busducts as well as secondary hazards caused by the degrading effect of the magnetic field on ferromagnetic structural materials (in reinforced concrete structures). Attention is given to an ergonomic aspect of interaction of the magnetic field with cathode ray tube computer monitors (annoying oscillation of the image).     

Health Risk Assessment of Occupational Exposure to a Magnetic Field From Magnetic Resonance Imaging Devices

Health care staff who operate magnetic resonance imaging (MRI) devices are exposed to a static magnetic field of significant spatial heterogenity always produced by MRI magnets during the whole shift. They can also be exposed to pulses of a time-varying magnetic field (gradient field) present only during patients’ examinations. The level of the workers’ exposure depends both on the type of the magnet and on the ergonomic design of each MRI device.

The paper presents methods used for measuring and assessing workers’ exposure. It also discusses the results of inspection measurements carried out next to approximately 20 MRI devices of approximately 0.2–2.0 T. The presented characteristic and overview of the variability of workers’ exposure to a variety of MRI devices supports the need for data on monitoring occupational exposure to MRI. International exposure assessment standards and guidelines (International Commission on Non-Ionizing Radiation Protection [ICNIRP], Institute of Electrical and Electronics Engineers [IEEE], American Conference of Governmental and Industrial Hygienists [ACGIH], European Commission directive), and those established in Poland are also compared.     

电磁脉冲作用下单极子天线的超宽带响应

目的提出求解短波单极子天线在外界电磁脉冲作用下宽带响应的数值算法——基于利用矩量法的时域积分方法。方法为展开未知电流的时域系数,采用拉盖儿多项式作为整个时域空间中的展开基函数,对单极子天线的瞬态响应进行数值模拟,并和试验数据进行对比验证。结果文中提出的方法与试验数据匹配良好。结论试验结果验证了该方法的有效性,该分析方法可为天线或系统对外界有意电磁干扰的响应及防护研究提供输入条件。     

高压输变电工程电磁场对环境的影响及．防治

通过对高压输变电工程电磁场的研究，讨论了高压输变电工程产生的电磁场对环境及人体健康的影响，提出了降低高压输变电工程电磁场影响的相关对策和建议。