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111.
112.
输气干线分输站站址规划设计合理与否,直接影响到分输站至各城市门站之间输气管线总投资和未来管网系统的发展。为此,着重讨论并建立了以分输站站址、各城市门站与分输站之间管道直径、壁厚、分输站压力为设计变量,以各城市门站与分输站之间管道投资最小为目标函数的分输站站址优化数学模型。根据模型特点,采用混合离散变量复合形法与数据库技术相结合来求解分输站站址。以此站址为参考点,结合现场勘察,在参考点附近沿输气干线预选多个分输站站址,并对影响分输站建设和管理的环境因素用多目标模糊评价方法进行综合评价,以评价效果好的站址为最优分输站站址。用算例说明了分输站站址优化结果不仅与工艺参数变化有关,且与分输站所处环境因素有关。提出还应深入研究输气干线中具有多个分输站的站址优化问题。 相似文献
113.
为了客观、准确地对招投标的规范化进行评判,依据《中华人民共和国招标投标法》选取公开、公平、公正和诚实信用四大指标为招投标规范化的评判特征因子。在此基础上,引入可拓学理论,建立了招投标规范化评判物元模型,给出了基于关联函数的可拓评判方法。并结合某招投标活动,实际评判了其规范化综合水平。 相似文献
114.
微波干燥原理及其应用 总被引:31,自引:1,他引:30
介绍了微波干燥的原理和主要特点及其应用的现状,并且给出了微波干燥经济核算的计算方法。 相似文献
115.
关于建立纺织用染化料生态安全性评价体系的设想 总被引:2,自引:1,他引:1
从可持续发展战略和“绿色”、环保、生态等方面的需要提出关于建立纺织用染化料生态安全性评价体系的意义,并建议了列入安全性评价体系的项目及实施办法,同时也提出了需要解决的问题。 相似文献
116.
Jong Min Kim Donghee Lee Sang Lyul Min Chong Sang Kim 《Information Processing Letters》2003,85(2):93-97
A new dynamic buffer allocation strategy based on the notion of marginal gains is presented for the buffer cache that is used by the operating system to store frequently accessed disk blocks in main memory, and the performance of the proposed strategy is compared with those of previous allocation strategies. In the proposed strategy, marginal gain values are predicted by exploiting functions that approximate the expected number of buffer hits per unit time. Experimental results from both trace-driven simulation and an actual implementation in the FreeBSD operating system show that the proposed strategy accurately predicts the marginal gain values for various workloads resulting in significantly improved buffer hit ratios. 相似文献
117.
液体酚型抗氧剂的制备及性能评定 总被引:1,自引:0,他引:1
以2,6-二叔丁基苯酚和丙烯酸酯为主要原料制备出一种液体酚型抗氧剂新产品羟基苯基丙酸酯化合物(LA0)。对制备的LAO的结构、组成及理化性能特别是抗氧化性能进行了分析评定。结果表明:LAO具有油溶性好、使用方便、特别是高温抗氧化能力强等优点,质量达到国外同类优质产品水平,并具有良好的环保性。 相似文献
118.
Cunningham William A.; Johnson Marcia K.; Gatenby J. Chris; Gore John C.; Banaji Mahzarin R. 《Canadian Metallurgical Quarterly》2003,85(4):639
Evaluative responses appear to involve 2 seemingly distinct sets of processes: those that are automatically activated and others that are more consciously controlled. Using functional magnetic resonance imaging, the authors investigated the brain systems associated with automatic and controlled evaluative processing. Participants made either evaluative (good-bad) or nonevaluative (past-present) judgments about famous names. Greater amygdala activity was observed for names rated as "bad" relative to those rated as "good," regardless of whether the task directly involved an evaluative judgment (good-bad) or not (past-present). Good-bad judgments resulted in greater medial and ventrolateral prefrontal cortex (PFC) activity than past-present judgments. Furthermore, there was greater ventrolateral PFC activity in good-bad judgments marked by greater ambivalence. Together, these findings indicate a neural distinction between processes engaged for automatic and controlled evaluation. Whereas automatic processes are sensitive to simple valence, controlled processes are sensitive to attitudinal complexity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
119.
Binoy Ravindran Peng Li Tamir Hegazy 《Journal of Parallel and Distributed Computing》2003,63(12):1219-1242
We present two proactive resource allocation algorithms, RBA*-FT and OBA-FT, for fault-tolerant asynchronous real-time distributed systems. The algorithms consider an application model where task timeliness is specified by Jensen's benefit functions and the anticipated application workload during future time intervals is described by adaptation functions. In addition, we assume that reliability functions of processors are available a priori. Given these models, our objective is to maximize aggregate task benefit and minimize aggregate missed deadline ratio in the presence of processor failures. Since determining the optimal solution is computationally intractable, the algorithms heuristically compute sub-optimal resource allocations, but in polynomial time. Experimental results reveal that RBA*-FT and OBA-FT outperform their non-fault-tolerant counterparts in the presence of processor failures. Furthermore, RBA*-FT performs better than OBA-FT, although OBA-FT incurs better worst-case and amortized computational costs. Finally, we observe that both algorithms robustly withstand errors in the estimation of anticipated failures. 相似文献
120.
On irrigation schemes with rotational irrigation systems in semiarid tropics, the existing rules for water allocation are based on applying a fixed depth of water with every irrigation irrespective of the crops, their growth stages, and soils on which these crops are grown. However, when water resources are scarce, it is necessary to allocate water optimally to different crops grown in the irrigation scheme taking account of different soils in the command area. Allocating water optimally may lead to applying less water to crops than is needed to obtain the maximum yield. In this paper, a three stage approach is proposed for allocating water from a reservoir optimally based on a deficit irrigation approach, using a simulation-optimization model. The allocation results with a deficit irrigation approach are compared for a single crop (wheat) in an irrigation scheme in India, first with full irrigation (irrigation to fill the root zone to field capacity) and second with the existing rule. The full irrigation with a small irrigation interval was equivalent to adequate irrigation (no stress to the crop). It is found that practicing deficit irrigation enables the irrigated area and the total crop production in the irrigation scheme used for the case study to be increased by about 30–45% and 20–40%, respectively, over the existing rule and by 50 and 45%, respectively, over the adequate irrigation. Allocation of resources also varied with soil types. 相似文献