学习《建筑物防雷设计规范》GB50057-94局部修订条文的几点心得

国家标准<建筑物防雷设计规范>GB50057-94局部修订条文自2000年10月1日起施行,原规范中相应条文同时废止.广大防雷工作者需要及时了解并应用于实际工作中,此文是笔者结合防雷工作的几点心得.     

台站短波(五则)

1月 2 1日 ,呼盟气象局召开局务会议传达贯彻全区气象局长工作会议精神 ,盟局各科 (室 )的主要负责同志参加了会议。 (薛德友 )巴盟气象局上政务信息网 ,用以宣传扩大自我形象 ,加强与外界的电子信息沟通 ,拓展气象科技服务和产业服务领域。 (群　力 )日前 ,东苏气象局召开了站     

费县地下水分布规律及其水质特征浅析

本文阐述了县内第四系孔隙水富水区、灰岩岩溶水富水区、变质岩贫水区、碎屑岩贫水区的水文地质构造、地下水分布状况及单井出水量的大小。采用模糊数学法对水质现状及趋势进行了分析评价，总体上水于恶化趋势。认为加强地下水保护已成当务之急。     

试验性开采抽水试验在新疆库车县兵团大化肥项目水源地勘探中的应用

试验性开采抽水试验的应用，保证了水源地允许开采量的计算精度，为水源地建设设计了可靠的依据。     

南水北调中线河北供水区各市区工业用水综合分析评价

本文通过对河北供水区七个市的工业取水量 ,用相对基准的方法调到同一水平 ,通过建立数学模型—比差率 ,再结合各市工业结构现状分析比较 ,得出各市的工业用水节水现状及差距并进行了综合评价     

Reconstruction of the climate in the Tianmu Mountain area, Zhejiang Province, in the last 160 years by ? 13C sequence of tree ring α-cellulose

Based on cross-dating tree rings from the Tianmu Mountain, Zhejiang Province, the tree rings α-cellulose δ 13C time series was measured. By spectrum analysis, the variation of tree-ring δ13C sequence shows a quasi periodicity of 4.4 years, which is coincident with the standard cycle of El Nino. After removing the long-term decrease trend of the δ13C variation related to atmospheric CO2 concentration, the response of the δ13C to climate elements was analyzed using meteorology data from a nearby weather station. The results suggest that there is a distinct relativity between high-frequency variation of tree ring δ 13C series and seasonal climate parameters, e.g. Temperature and precipitation, with a significant time-lag effect. In addition, the high frequency also reflects the strength change of the East Asian Monsoon. The multiple regression method was employed to reconstruct the historical climate, and to analyze the climate change and trend in the last 160 years in the northern Zhejiang Province.     

Reconstruction of the diagenesis of the fluvial-lacustrine- deltaic sandstones and its influence on the reservoir quality evolution-- Evidence from Jurassic and Triassic sandstones, Yanchang Oil Field, Ordos Basin

The reservoir quality of Jurassic and Triassic fluvial and lacustrine-deltaic sandstones of the Yanchang Oil Field in the Ordos Basin is strongly influenced by the burial history and facies-related diagenetic events. The fluvial sandstones have a higher average porosity (14.8%) and a higher permeability (12.7×10?3 ?m2) than those of the deltaic sandstones (9.8% and 5.8 ×10?3 ?m2, respectively). The burial compaction, which resulted in 15% and 20% porosity loss for Jurassic and Triassic sandstones, respectively, is the main factor causing the loss of porosity both for the Jurassic and Triassic sandstones. Among the cements, carbonate is the main one that reduced the reservoir quality of the sandstones. The organic acidic fluid derived from organic matter in the source rocks, the inorganic fluid from rock-water reaction during the late diagenesis, and meteoric waters during the epidiagenesis resulted in the formation of dissolution porosity, which is the main reason for the enhancement of reservoir-quality.     

Evapotranspiration from citrus trees growing in sandy soilunder drip irrigation with saline water

An experiment on evapotranspiration from citrus trees under irrigation with saline waterwas carried out for 4 months. Two lysimeters planted with a citrus tree in the green house wereused. One lysimeter was irrigated with saline water (NaCl and CaCl2 of 2000 mg/L equivalence,EC = 3.8 dS/m, SAR = 5.9) and the other was irrigated with freshwater using drip irrigation. Theapplied irrigation water was 1.2 times that of the evapotranspiration on the previous day.Evapotranspiration was calculated as the change in lysimeter weight recorded every 30 minutes.The lysimeters were filled with soil with 95.8% sand. The results of the experiment were as follows.(i) The evapotranspiration from citrus tree was reduced after irrigation with saline water. Theevapotranspiration returns to normal after leaching. However it takes months to exhaust the saltfrom the tree. ( ii ) To estimate the impact of irrigation with saline water on the evapotranspirationfrom citrus trees, the reduction coefficient due to salt stress (Ks) was used in this experiment.Evapotranspiration under irrigation with saline water (ETs) can be calculated from evapotranspira-tion under irrigation with freshwater (ET) by the equation ETs = Ks× ET. Ks can be expressed as afunction of ECsw. (iii) The critical soil-water electrical conductivity (ECsw) is 9.5 dS/m, beyondwhich adverse effects on evapotranspiration begin to appear. If ECsw can be controlled at below9.5 dS/m, saline water can be safely used for irrigation.     

Impact of oasis establishment on underground environment in salinized sandy lands

The salinized sandy lands are the important reclaimable reserve wastelands in thesouth area of the Xinjiang Uygur Autonomous Region of China. But it is necessary that the eco-logical environment of the area is not destroyed by action of oasis development. The main factor tohinder oasis development is land salinization. Rational oasis establishment rebuilds wastelandswith lower productivity and utilization efficiency for the growth of agriculture, forestry, and stock raising. The results of surveying sub-soil environment of Aimugaike. Awati oasis in Hotian County ofthe Xinjiang Uygur Autonomous Region show that the underground water and soil environment arenot deteriorated under the rational management and administration, which could be coordinatedfor obtaining economic and environmental benefit. During the oasis establishment period from1997 to 1999, the plowland area has reached 166.7 hm2, and the seed cotton yield per unit areahas reached 2250 kg @ hm-2, the area of timber forest and active sand break forest has reached 20hm2, the area of fruit trees is 71.5 hm2; and the soil moisture has decreased from 22.07% to18.12%. In the first year of oasis establishment, the soil type has changed salt soil into light saltsoil, in the second year the soil has been out of salt harm; and the content of soil organic matter intopsoil has increased obviously.