982 resultados para 312.432
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Computer modelling approaches have significant potential to enable decision-making about various aspects of responsive manufacturing. In order to understand the system prior to the selection of any responsiveness strategy, multiple process segments of organisations need to be modelled. The article presents a novel systematic approach for creating coherent sets of unified enterprise, simulation and other supporting models that collectively facilitate responsiveness. In this approach, enterprise models are used to explicitly define relatively enduring relationships between (i) production planning and control (PPC) processes, that implement a particular strategy and (ii) process-oriented elements of production systems, that are work loaded by the PPC processes. Coherent simulation models, can in part be derived from the enterprise models, so that they computer execute production system behaviours. In this way, time-based performance outcomes can be simulated; so that the impacts of alternative PPC strategies on the planning and controlling historical or forecasted patterns of workflow, through (current and possible future) production system models, can be analysed. The article describes the unified modelling approach conceived and its application in a furniture industry case study small and medium enterprise (SME). Copyright © 2010 Inderscience Enterprises Ltd.
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酸性矿山废水中低的pH和高浓度的重金属对水生态系统影响巨大。依据"参照(Control)-受损(Impaired)-恢复(Recovery)"的设计方法,对高岚河受酸性矿山废水影响的河段、不受影响的河段及恢复河段进行对比分析。结果表明底栖藻类密度、叶绿素a浓度、无灰干重及自养指数等受酸性矿山废水影响明显,且枯水期酸性矿山废水的影响更显著。相关分析表明自养指数与各金属显著正相关而与pH值显著负相关,可以很好地指示矿山酸性废水对底栖藻类的影响。
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采用复合垂直流人工湿地系统,研究了人工湿地处理养殖废水过程中,湿地基质空隙中TSS(Total Suspended Solids)的动态变化及去除规律。中试实验结果表明,系统对TSS有良好的净化效果,平均去除率达到70%。循环养殖废水在复合垂直流人工湿地流动时,TSS的去除主要发生在下行池单元上层区域,沿水流方向,随着距离的延长,TSS的降解速率呈现先快后慢的趋势,同时根据动态变化曲线形式,建立了该实验条件下TSS在湿地床内沿程动态变化模型:CL=C0exp(2.967×10-4L2-0.04316L),
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报道了土壤样品中痕量六溴环十二烷(HBCDS)的超高效液相气谱/质谱联用分析方法(UPLC/MS)。结果表明,该方法在9 min内即可完成α-HBCD、β-HBCD和γ-HBCD3种同分异构体的分离,回收率为79.3%~109.9%,在2.5~150 ng/mL范围内具有较好的线性,R2为0.991~0.998;α-HBCD、β-HBCD、γ-HBCD的检出限分别为20 pg、45 pg和15 pg。
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为探讨利用太阳光降解水中异味化合物的可行性,对2-甲基异莰醇(MIB)、β-柠檬醛(β-Cyclocitral)和β-紫罗兰酮(β-Ionone)等3种异味化合物在紫外光和太阳光下的光降解及光催化降解效果进行了研究。结果表明,单波长紫外光——UVC(254 nm)和UVB(312 nm)及太阳光均能有效降解纯水中的β-Cyclocitral和β-Ionone,但不能降解MIB。加入纳米TiO2后,在UVC(254 nm)、UVB(312 nm)和太阳光照射下,MIB、β-Cyclocitral和β-Ion
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分析了分布于青藏高原及其邻近地区23个种和亚种36个群体高度特化等级裂腹鱼类的线粒体DNA细胞色素b序列,重建了系统发育关系.并采用地质隔离事件校正分支时间,估计了主要分支发生时间.结果发现,高度特化等级裂腹鱼类不是单系群,裸鲤属和裸裂尻属也不是单系群.全裸重唇鱼可能是特化类群向高度特化类群演化的过渡类型.高度特化等级裂腹鱼类的系统发育关系总体上反映了水系之间和地质历史的联系,即来自相同和相邻水系的物种通常具有更近的亲缘关系.估计的主要分支发生事件与青藏高原近晚地质时期强烈隆起有很好的一致性,表明高度特化
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Surface temperature measurements from two discs of a gas turbine compressor rig are used as boundary conditions for the transient conduction solution (inverse heat transfer analysis). The disc geometry is complex, and so the finite element method is used. There are often large radial temperature gradients on the discs, and the equations are therefore solved taking into account the dependence of thermal conductivity on temperature. The solution technique also makes use of a multigrid algorithm to reduce the solution time. This is particularly important since a large amount of data must be analyzed to obtain correlations of the heat transfer. The finite element grid is also used for a network analysis to calculate the radiant heat transfer in the cavity formed between the two compressor discs. The work discussed here proved particularly challenging as the disc temperatures were only measured at four different radial locations. Four methods of surface temperature interpolation are examined, together with their effect on the local heat fluxes. It is found that the choice of interpolation method depends on the available number of data points. Bessel interpolation gives the best results for four data points, whereas cubic splines are preferred when there are considerably more data points. The results from the analysis of the compressor rig data show that the heat transfer near the disc inner radius appears to be influenced by the central throughflow. However, for larger radii, the heat transfer from the discs and peripheral shroud is found to be consistent with that of a buoyancy-induced flow.
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研究了四种常见优势底栖螺类的饥饿代谢(R,mgO2/ind.d)与温度(T,℃)、体重(Wd,mg dry-wt或Ww,mg wet-wt)的关系,并计算出三者间的复合关系,分别是:铜锈环棱螺,R=0.044Wd0.537e0.061T;长角涵螺,R=0.0004Ww0.9405·e0.0735T;纹沼螺,R=0.004Wd1.072e0.091T;短沟蜷,R=0.023Wd0.777e0.042T。
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采用随机扩增多态性DNA(RAPD)方法对青海湖裸鲤的3个洄游繁殖群体-黑马河(HM)、布哈河(BH)及沙柳河(SL)群体各30个个体的DNA多态性进行了分析。用13个引物在三个群体中共检测出85个位点,其中多态性位点68个。青海湖裸鲤群体总的DNA多态位点百分率为80.0%。数据分析结果显示:青海湖裸鲤3个群体总的Nei基因多样性为0.3395,Shannon遗传多样性信息指数为0.4861,存在着较为丰富的遗传多样性。青海湖裸鲤3个群体间平均遗传距离为0.0788,基因分化系数Gst为0.1070,表
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人工湿地污水处理系统具有净化效果显著、建设和运行费用低廉、管理简便等优点.近年来越来越受到人们的重视.人工湿地生态系统受环境影响较大,研究人工湿地在不同季节的净化功能对于充分发挥其作用具有重要意义.对不同季节的芦苇(Phragmite saus-tralis)、茭白(Zizania caduciflora)和香蒲(Typha latifolia)等湿地系统植物根区、无植物对照基质微生物分布状况以及净化效果进行了研究,结果显示:(1)种植不同植物的湿地系统根区微生物数量不同,其湿地净化效果也不同;(2)季节
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Healthcare systems worldwide face a wide range of challenges, including demographic change, rising drug and medical technology costs, and persistent and widening health inequalities both within and between countries. Simultaneously, issues such as professional silos, static medical curricula, and perceptions of "information overload" have made it difficult for medical training and continued professional development (CPD) to adapt to the changing needs of healthcare professionals in increasingly patient-centered, collaborative, and/or remote delivery contexts. In response to these challenges, increasing numbers of medical education and CPD programs have adopted e-learning approaches, which have been shown to provide flexible, low-cost, user-centered, and easily updated learning. The effectiveness of e-learning varies from context to context, however, and has also been shown to make considerable demands on users' motivation and "digital literacy" and on providing institutions. Consequently, there is a need to evaluate the effectiveness of e-learning in healthcare as part of ongoing quality improvement efforts. This article outlines the key issues for developing successful models for analyzing e-health learning.
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198 9~ 1999年 ,在长江八里江江段对江豚进行了 2 8次往返观察和 8次定点观察。结果表明 ,近 10年八里江江段江豚种群数量逐年呈明显递减趋势 ,平均每年以 7.3%速率递减 ;1996年后 ,枯水季节江豚不再进行江—湖迁移 ,其活动范围仅限于 2 0km的长江八里江江段 ,较 1993年以前缩短了约 40km。江豚在八里江江段的行为多种多样 ,通过对江豚种群在八里江江段的集群、摄食、逃避、发情与交配、抚幼、歇息和玩耍行为的描述、比较和分析 ,认为长江八里江江段是江豚典型的摄食和抚幼场所 ,同
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通过对红鲤、红鲫、镜鲤、鲤鲫杂种二倍体一代 ,二代 ,鲤鲫杂种三倍体 ,鲤鲫复合三倍体 ,鲤鲫杂种四倍体一代 ,二代的同工酶及蛋白电泳谱型和扫描数据分析表明 :在鲤鲫人工多倍体谱系中 ,亲代的等位基因在杂交子代中共有四种表达模式 :( 1 )两亲本基因在子代中共同表达 ,即共显表达 ;( 2 )父本的基因表达受到部分或完全的抑制 ,即母本的基因优先得到表达 ;( 3)母本的基因表达受到抑制 ,父本的基因得到表达 ;( 4 )双亲本的基因表达均受到一定程度的抑制或都不表达。其中第一种表达模式是主要的模式。根