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891.
The Sandhills region represents a tremendous water resource for the State of Nebraska. Small shallow lakes, marshes, and subirrigated meadows are abundant due to interactions between ground water and surface water. One theory relating ground water to lake-flow systems in the Sandhills has been termed the “flow-through” concept. Thermal-infrared remotely acquired images document the flow-through model for a test site in Western Nebraska.  相似文献   
892.
ABSTRACT: Twenty-six aspen (Populus tremuloides Michx.), 20 subalpine fir (Abies lasiocarps (Hook.) Nutt.), and 20 Engelmann spruce (Pices engelmanil (Parry) Engelm.) of various sizes were cut under water and suspended in permanent reserviors at a northern Utah site. The reservoirs were asealed so that all water loss was due to consumption by the trees. Sap velocities, as computed from heat pulse velocities, were related to conducting areas of the tree trunks. Computed transpiration volumes were then correlated with actual water losses from the reservoirs. Coefficients of determination (R2) of 0.87, 0.86, and 0.82 were obtained for the fir, aspen, and sprucs, respectively. Reservoir water loss for each species for each season was then used to adjust a plant activity index for computing transpiration within ASPCON, a model describing the hydrology of aspen to conifer succession. The plant activity index reflects the variation in the capability of a plant community to transpire water over the year. Assumptions and limitations of the heat pulse velocity technique are also outlined.  相似文献   
893.
ABSTRACT: Data from a small forested catchment were used to model peak stream flow as a function of basic hydrologic variables associated with 112 rain storms. Rainfall depth and initial stream flow rate accounted for 87.1 percent of peak flow variability. Forty expressions of rainfall intensity (describing both the temporal sequence of intensity for 20 equal storm intervals, and maximum intensity for 20 separate interval lengths) were used in an attempt to improve the predictability of basic models. None of the intensity parameters improved predictability by as much as 2 percent, apparently because the most intense rainfall bursts generally occurred near the beginning of storm periods. Mean rainfall intensity for entire storms was generally as effective as any of the shorter interval intensities, and its use helped to linearize the relationship between peak flow and rainfall depth and duration.  相似文献   
894.
895.
刘明礼 《四川环境》1993,12(3):74-76
本文从环境保护角度分析了氯化物对环境的影响。从而提出了制订“气田水中氯化物含量排放标准”的建议,讨论了气田水的处理方法。  相似文献   
896.
ABSTRACT: An evaluation of the Leadville, Colorado, precipitation records that include a reported record-breaking storm (and flood) at higher elevations in the Rocky Mountains has indicated that the use of an experimental Marvin windshield (designed to decrease the effects of wind on precipitation-gage catchment of snow during winter) resulted in substantially overregistered summer precipitation for 1919 to 1938. The July monthly precipitation for these years was over-registered by an average of 157 percent of the long-term July monthly precipitation at Leadville. The cause of the overregistration of precipitation was the almost 4-foot-top-diameter cone-shaped windshield that had the effect of “funneling” hail and rain splash into the rain gage. Other nearby precipitation gages, which did not use this Marvin windshield, did not have this trend of increased precipitation for the same period. Streamflow records from the Leadville area also do not indicate an increase in streamfiow from 1919 to 1938. The storm of July 27, 1937, considered one of the few, large, intense rainstorms at higher elevations, had a recorded precipitation of total 4.34 inches (4.26 inches in 1 hour). Streamflow-gaging-station records indicate that only 0.09 inch of storm runoff occurred. Paleoflood investigations of channels in the Leadville area and old newspaper accounts also indicate no substantial flood from this storm. This study indicates that the 1937 storm probably totaled about 1.7 inches of precipitation, much of which occurred as hail.  相似文献   
897.
为解决医疗行业废物排放量核定难的问题,通过对医疗机构废物产生量的调查、统计、分析,在确定医疗废物排放统计变量的基础上,得出相应的医疗废物排放系数,以供排污申报医疗废物排放量的核定。  相似文献   
898.
强电场电离放电脱硫研究   总被引:8,自引:0,他引:8  
窄脉冲电晕放电等离子体中电子平均能量低于3eV,没有解决SO2氧化和铵盐回收率难题,强电离放电的电子平均能量达到10eV,有效解决热化学脱硫的SO2氧化和铵盐回收率问题。铵盐回收率达到88%以上,放电能耗低于9Wh/Nm^3。为烟气脱硫提供一项低成本有效的新方法。  相似文献   
899.
本文通过对高压脉冲电晕放电产生的等离子体活性物质对发动机尾气中的NO进行活化 ,研究其净化率与电压、频率、风速以及初始浓度的关系及其相互之间的影响 ,同时研究NO的产物NO2 随电压、频率、风速以及初始浓度的生成关系 ,实验表明 ,NO的净化率能够达到 5 0 %以上 ,在风速不大的条件下 ,NO转化的主要产物为NO2  相似文献   
900.
非平衡放电等离子体治理有害气体   总被引:17,自引:0,他引:17  
重点分析了常温常压下非平衡放电等离子体产生的条件及其物理和化学性能,综合评述了放电技术的理烟气中有害气体SO2,NOx,CO2的机理和研究现状。  相似文献   
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