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采购方式的选择是确定采购策略的重要内容,更是影响采购效益的关键环节。本文根据河南油田近年来在选择采购方式上存在的不足,提出了选择合理采购方式的对策措施。 相似文献
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通过选择合适的曝气设施可以控制曝气方式,曝气方式的选择影响着堆肥发酵的整个过程;文章讨论了正负压的曝气方式的优缺点,同时也论述了不同曝气结构,通过以上的讨论为污泥好氧发酵曝气方式选择及运行成本控制提供一定的参考价值。 相似文献
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通过选择合适的曝气设施可以控制曝气方式,曝气方式的选择影响着堆肥发酵的整个过程;文章讨论了正负压的曝气方式的优缺点,同时也论述了不同曝气结构,通过以上的讨论为污泥好氧发酵曝气方式选择及运行成本控制提供一定的参考价值。 相似文献
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简述了某化工企业新建工业循环水系统电机启动方式选择设计过程,通过对比软启动与变频启动方式优缺点,选择最优的组合启动方式,提出合理的设计配置方案。 相似文献
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《硫磷设计与粉体工程》2017,(5)
随着化工企业运输量日益增大,如何有效的控制运输成本,选择适合的运输方式成为物流园需要面临的选择。介绍了运输方式的选择根据,如货物品种、运输量、前期投资成本、日常运输成本等,并对各种运输方式进行比较和分析,最终确定运输方式或其组合。 相似文献
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张林 《中国石油和化工标准与质量》2022,(6):48-50
为使得射线检测技术可以在在役石油化工承压设备检测中得到更好应用,需要相关工作人员能够意识到工艺优化选择工作的重要作用.通过合理选择射线源与能量、合理选择透照方式、合理选择焦距、合理选择胶片系统等不同方式,使射线检测工艺能够充分发挥自身作用,为设备正常运行打下良好基础. 相似文献
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在世界经济一体化迅猛发展的今天,建立战略供应商关系是目前国内外大企业降低采购成本的共同选择。框架协议招标将招标采购方式与战略供应商的选择进行了有机结合,通过充分发挥集团公司的整体优势,实现战略供应商的合理合法选择,是战略供应商选择过程中值得探索的新方式。 相似文献
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<正>露天矿开拓运输系统是矿山生产的中心环节,开拓方式与运输方式密切联系,露天矿开拓方式分类主要依据运输方式确定。1影响开拓方案选择的因素1.1根据矿山特定地形、地貌、地质和矿体赋存条件选择对矿体赋存条件较浅、平面尺寸较大的矿体,可采 相似文献
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本文采用限元工具建立实际水平井眼弹塑性模型,结合有效塑性应变准则,在某气田原地地应力及岩石强度参数的基础之上,研究了酸化前后井壁稳定性的变化情况,地层压力衰竭后井壁稳定性情况及它们对完井方式选择的影响,研究表明酸化措施对完井方式的选择有较大影响,酸化前可采用裸眼完井,在酸化后需采用支撑井壁类的完井方式,地层压力衰竭也对完井方式选择有一定影响。 相似文献
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本文详尽的介绍了在Ansys软件平台下裸眼完井和射孔完井有限元三维模型的建立及网格划分方法。用热流场模拟渗流场,用无限大导热材料模拟井筒和孔眼,可以很好的模拟射孔完井渗流场。利用所建模型分析了裸眼完井和射孔完井的渗流场速度分布,分别得出了其出口处的面流量,然后计算了产率比。另外编写了APDL语言,可以方便的修改射孔完井参数和地层参数,以更快捷的方式来预测产率比。 相似文献
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The anodically first formed oxide on gold (oxide I) reaches two complete monolayers, ie 1.5 mC cm?2 oxide charge, before a second type of oxide (oxide II) starts to form. Electrochemical redox reactions with redox couples such as the tris(o-phenantroline) ferrous/ferric ion couple and others which are well known to behave reversibly on bare gold are inhibited completely by gold covered with this critical coverage of two monolayers of oxide I. Up to nearly completion of this two monolayer coverage, the redox reactions behave reversibly. In the transition to the completion of two monolayers the reaction appears to be increasingly irreversible. This behaviour is explained on the basis of diffusion layer thickness, heterogeneous rate constants and the size and distribution of the active bare gold sites as well as of the inhibiting oxide covered sites on the surface. The inhibition by two complete monolayers of gold oxide seems to be of general character for redox couples independent of pH and electrolyte. 相似文献
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"5.12"汶川地震期间,普光气田膏盐地层蠕变导致多数气井发生套管变形,其中部分井变形严重,已经不能下入酸压生产一体化完井投产管柱,无法进行正常的投产作业。气田投产建设面临十分严峻的形势。针对这种情况,提出了"分类投产"的投产思路,按照套变程度,将套变井分成轻度、中度和严重套变三种类型,分别设计出不同的完井投产管柱,特别针对严重套变井,创造性地提出"遇油膨胀封隔器+永久式封隔器"的管柱结构,满足了酸压作业与长期生产的需要。各种投产工艺在现场得到了较好的应用,为普光气田产能建设提供了技术保证。 相似文献
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《Computers & Chemical Engineering》1987,11(4):345-356
The approximate two step strategy of Part I is extended to multiunit systems operating under the makespan criterion. The completion time calculation requires multiple readjustments of unit assignments for each product; involves a more complex storage feasiblity test than that in the two unit case; and is a suboptimal polynomial order procedure. Numerical test results show that the performance of the completion time algorithm is inversely dependent on the number of assigned storage vessels: problems with fewer vessels are progressively more difficult than those with more vessels. The sequence selection subproblem is solved using existing approximate algorithms for the UIS problem. The approximate strategy is compared on the basis of average case performance to schedules generated using a branch and bound method. The approximate algorithm yields a makespan within less than 6% on average of the branch and bound makespan when applied to a test set of 280 randomly generated problems. 相似文献
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Lili Wang Xiaolei Xu Mingming Teng Guimin Zhao Anmin Lei 《International journal of molecular sciences》2020,21(23)
As a common injury almost all cells face, DNA damage in oocytes—especially double-strand breaks (DSBs), which occur naturally during the first meiosis phase (meiosis I) due to synaptic complex separation—affects the fertilization ability of oocytes, instead of causing cancer (as in somatic cells). The mechanism of oocytes to effectively repair DSB damage has not yet been clearly studied, especially considering medically induced DSBs superimposed on naturally occurring DSBs in meiosis I. It was found that maturation rates decreased or increased, respectively corresponding with overexpression or interference of p21 in bovine oocytes. At the same time, the maturation rate of bovine oocytes decreased with a gradual increase in Zeocin dose, and the p21 expression in those immature oocytes changed significantly with the gradual increase in Zeocin dose (same as increased DSB intensity). Same as p21, the variation trend of ATM expression was consistent with the gradual increase in Zeocin dose. Furthermore, the oocytes demonstrated tolerance to DSBs during meiosis I, while the maturation rates decreased when the damage exceeded a certain threshold; according to which, it may be that ATM regulates the p53–p21 pathway to affect the completion of meiosis. In addition, nonhomologous recombination and cumulus cells are potentially involved in the process by which oocytes respond to DSB damage. 相似文献
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针对电力负控管理系统的客户端连接数量多、数据接收和发送频繁的现状,提出一种基于I/O完成端口(IOCP:I/O completion port)机制的大规模负控管理系统体系结构。研究了引入IOCP机制的通信模块的基本原理、实现方案和关键问题解决方法。进一步提出了负控管理系统上层软件的架构。最后通过模拟测试和实际项目证明:基于IOCP机制的负控管理系统开销性低、准确性高。 相似文献
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黄88支平1井是江苏油田第一口水平分支井,本文通过调研和理论研究,预测了该井的完井产能,优选了该井的完井方式、完井管柱以及完井配套工具,对今后江苏油田水平分支井的完井工艺具有一定的指导意义。 相似文献