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991.
根据不同河段的水域功能将污染严重的福田河自上而下划分为三个水污染控制单元,针对每个单元的不同环境目标和污染负荷预测得到相应的污染净化率,依此建立资源优化配置模型,由该模型获得优化决策,以期合理利用环境容量,确定最小净化费用,兴修必要的治理设施,从而保证在经济高速发展的同时,有效地控制福田河的污染问题。  相似文献   
992.
P Rodriguez  S L Mannan 《Sadhana》1995,20(1):123-164
Fatigue at high temperature is a complex phenomenon as it is influenced by a number of time-dependent processes which become important at elevated temperatures. These processes include creep, oxidation, phase instabilities and dynamic strain ageing (DSA), acting either independently or synergistically influence fatigue behaviour, often lowering the fatigue life. Current design approaches employ linear summation of fatigue and creep damage with suitable factors on permissible damage to take care of uncertainties in interaction between cyclic and time-dependent processes. It is, therefore, important to develop a deeper understanding of the processes that occur during high temperature fatigue so that realistic life predictions could be made. Results on the high temperature fatigue behaviour of austenitic stainless steels, ferritic steels and nickel base alloys are presented here. The important mechanisms of interaction of high temperature time-dependent processes with fatigue under various conditions are discussed in detail. Emphasis is placed on cyclic stress response, fatigue life, deformation substructure and fracture behaviour. This is followed by a review of important life prediction techniques under combined creep-fatigue loading conditions. Life prediction techniques considered here include linear damage summation, strain range partitioning, ductility exhaustion approach, frequency modified and frequency separation methods, techniques based on hysteresis energy and damage rate models, and methods based on crack-cavitation interation models.  相似文献   
993.
三维地震资料连片的一致性处理技术   总被引:7,自引:1,他引:6  
三维地震资料连片处理是一套复杂而精细的数字处理工作。根据各区块三维地震资料的频率、相位、时差、信噪比等的特殊性和差异性,采用叠前能量一致性、相位一致性和振幅一致性处理方法,对能量、振幅、相位等有效地进行一致性补偿和校正,使各区块资料在保持原有品质的前提下,既提高了信噪比和分辨率,又保证了资料整体拼接的一致性。应用该方法处理胜利桩海地区23块共1500km^2三维资料,取得了良好的效果。  相似文献   
994.
钢铁企业成本管理模式的比较分析   总被引:1,自引:0,他引:1  
张建斌 《河北冶金》2006,(3):118-122
对宝钢、武钢、邯钢的成本管理模式进行了比较分析,认为应该将标准成本、目标成本和责任成本有机地结合起来,构建更先进、合理、科学的企业成本管理模式.  相似文献   
995.
Potential for large-scale physical transport processes to affect recruitment of Lake Michigan yellow perch (Perca flavescens) was studied by examining the variation in larval distribution, growth rate, and settlement during June–August 1998–2003 using a 3D particle transport model linked with an individual-based bioenergetics growth model. In all years, virtual larvae were released nearshore in southwestern Lake Michigan, a known and important spawning region for yellow perch. For any given year, the same circulation pattern and water temperature either promoted or reduced yellow perch settlement depending on the consumption rates and settlement size chosen in the growth model. Increased consumption increased the number of settled larvae and expanded the total area where larvae settled, whereas increased settlement size reduced the number of settled larvae and reduced the overall settlement area. Interannual variability in circulation patterns and water temperature also resulted in contrasting larval settlement rates, settlement locations, and size of settlement areas between years. Model predictions were most consistent with field observations of age-0 yellow perch from Illinois and Michigan waters when settlement was assumed to occur at 50 mm. Moreover, our model suggests that larvae originating from southwestern Lake Michigan can recruit anywhere within the southern basin and even in the northern basin. Future model improvement will require information on the relative contribution of various sectors to the larval pool, their distribution with reference to the hydrodynamic landscape, the feeding and growth of yellow perch during their pelagic phase, and the size at transition to demersal stage.  相似文献   
996.
An integrated model is established to simulate both hydrological processes and accompanied pollutant transfer processes in the Yellow River Basin. The model couples distributed hydrological model WEP-L (Water and Energy transfer Processes in Large river basins) and a newly developed water quality module which includes simulation functions of soil erosion and sediment transport, and non-point and point sources transfer to rivers. To overcome the defects of traditional water quality assessment, two aspects of improvement are conducted. One is the improvement of the traditional characteristic channel length approach, i.e., the product of multiplying channel length by lateral section area is selected as a new assessment criterion to reflect the different contributions of small channels and big ones, thus making the assessment results more objective. The other is the suggestion of integrated assessment approach for both water at channel lateral sections and water generated in sub-basins. The assessment results in the Yellow River Basin illustrate: (1) the improved characteristic channel length approach shows rivers of water quality worse than Class III account for 75% whilst the traditional approach give a result of 45%, implying that the actual status of water quality is worse than the traditional understanding; (2) the quality of water generated in sub-basins is much better than the quality of water at channel lateral sections. The assessment results describe the status of water resources quantity and quality from different points of view and thus provide valuable information for the water resources development and management in the basin.  相似文献   
997.
简要介绍了水电厂资产管理系统的构成,从中引出了以设备为中心、以工作单为主线的资产管理模型,并说明了该模型在水电厂资产管理系统中的应用效果。  相似文献   
998.
通过二维物理模型试验,探讨了暗基床上空心块体在规则波作用下的失稳模式。通过试验观察发现,当空心块体内有一定高度的填料时,波浪正向作用下空心块体首先倾覆失稳。本试验测量了作用在空心块体上的波浪力,并与同尺寸沉箱所受的波浪力进行对比,结果显示在波峰时空心块体所受的总水平波浪力比相同波浪作用下的沉箱所受力小而波谷作用下空心块体所受的总水平波浪力却比相同波浪作用下的沉箱所受波浪力大。鉴于上述实验观察结果,空心块体的主要失稳模式分析方法应作进一步研究。  相似文献   
999.
对螺杆泵举升性能的影响因素进行了综合分析,建立了螺杆泵举升性能综合评价的指标体系,并利用模糊数学方法确立了该系统的综合评价模型,将该模型应用于2台GLB500—12型螺杆泵,其评价结果与在实际工作中的产液量和寿命的综合指标基本吻合,从而验证了该方法的正确性,为螺杆泵举升性能的综合评价提供了一种有效方法。  相似文献   
1000.
割缝防砂筛管抗挤强度有限元计算模型   总被引:3,自引:1,他引:2  
针对割缝防砂筛管周围或缝内部堵塞,造成井眼压力增加,可能会导致筛管被挤毁的问题,采用有限元方法,通过大型有限元程序,建立了其抗挤强度的有限元计算模型。根据弹塑性理论,对割缝防砂筛管进行分析,得出其抗挤强度。结果与国外的实验数据进行对比,数值模拟结果比实验值略大,但两者相差较小,证明了该模型的正确性。为其他尺寸割缝筛管的抗挤强度设计提供了一种数值计算方法。  相似文献   
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