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241.
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ABSTRACT: A spatial linear program that strategically arranges and schedules forest treatments so as to meet peak stormflow objectives is formulated and demonstrated. The approach uses simulated spatial routing of stormflows nested as short‐term time schedules within longer‐term forest planning time periods. A simple case example is used to demonstrate the formulation and explore its spatial sensitivity. 相似文献
243.
Richard L. Skaggs Larry W. Mays Lance W. Vail 《Journal of the American Water Resources Association》2001,37(4):853-866
ABSTRACT: Review of recent literature indicates an emergence in the use of combinatorial methods such as simulated annealing in ground water management during the past nine to ten years. While previous studies demonstrated the feasibility of using these methods, a general finding was that computational processing requirements were inordinately high relative to gradient‐based methods. An enhanced annealing algorithm was developed and used to demonstrate the potential for greatly improving the computational efficiency of simulated annealing as an optimization method for ground water management applications. The algorithm incorporates “directional search” and “memory” capabilities. Selecting search directions based on better understanding of the current neighborhood of the configuration space was shown to improve algorithm performance. Also, “memory” concepts derived from the Tabu Search Method show particular promise for improving the rate and quality of convergence. Performance of the enhanced annealing method was evaluated and the resultant management method was demonstrated using an example from the literature. 相似文献
244.
可持续发展与产业结构优化 总被引:20,自引:0,他引:20
可持续发展要求产业结构合理化、高度化、形成能够发挥资源禀赋比较优势的产业结构和发展环保产业,但是我国目前存在产业结构不合理、重复建设严重、地区产业结构趋同、产业技术水平低、第三产业发展不足、高新技术产业和环保产业发展滞后等情况,极不利于社会经济的可持续发展。为了真正的实现可持续发展,必须努力调整产业结构,淘汰落后过剩的生产能力,促进产业结构升级,大力发展第三产业、环保产业和高新技术产业。 相似文献
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246.
采用模糊集的贴近度计算对齿轮表面探伤方法进行了优化选择,表明旋转磁场探伤是齿轮表面探伤的最佳方法,在实用中检测出大量的正在延伸扩展的表面疲劳裂纹. 相似文献
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248.
Spalinger SM von Braun MC Petrosyan V von Lindern IH 《Environmental monitoring and assessment》2007,130(1-3):57-72
House dust has been identified as a major exposure medium for lead (Pb) in children. High levels of Pb in soil and house dust
have been recorded at the Bunker Hill Superfund Site (BHSS) in northern Idaho, an historic mining and smelting district. Soil
and dust remediation at the site was required; however, regional background soil and dust Pb levels had not been well characterized.
The objective of this survey was to determine background house dust Pb levels and to compare those levels with concentrations,
and dust and Pb loading rates measured at the BHSS. Soil and house dust samples were collected in five towns demographically
similar to the BHSS but unaffected by the mining industry. The background concentrations and loading rates were significantly
lower than those observed at the site. House age was a significant factor affecting background soil and house dust Pb concentrations
and loading rates. 相似文献
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250.
目前对造纸废水的监测通常采取随机取样,很少考虑污染物在废水中的分布情况,所以取得的样品很难反映污染物的实际排放情况。为此,通过对某造纸厂排废废水中化学需氧量分布夫妻及采样点位的优化研究。 相似文献