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21.
解顺强。转移概率流向图的概率理论基础与应用方法(Ⅵ)-中止规则对调整型抽样方案复合OC函数影响的进一步讨论。数理统计与管理。1998.17(6)本文运用转移概率流向图及其粘接方法,证明了当检查始于加严抽样方案时,不带中止规则的调整型抽样方案与带中止规则的相应的调整型抽样方案,两者的复合OC函数相同。 相似文献
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目前水平井机械找水主要通过井下开关控制逐段生产找水,随着水平井改造段数逐年增加,造成找水测试周期较长,需要将可能见水的射孔段组合进行找水.由于水平井对应注水井多、微裂缝发育造成缝网关系复杂以及超低渗透储层非均质性强,导致来水方向及井筒见水位置判识难度大.以已完成找水措施的水平井各射孔段油藏参数和改造参数为基础,采用灰色关联法对参数优选,并对优选参数进行模糊聚类分析,将聚类结果应用于新见水水平井的出水位置预判,形成一种多段压裂水平井见水层段的辅助判识方法,可将见水层段优化组合,达到缩短水平井找水周期的目的. 相似文献
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用XRD、IR和TPR等技术研究了钙钛矿型复合氧化物的晶体结构及其反应性能.整个组成范围内,LaNi_(i-x)Mn_xO_3(0.0≤x≤1.0)体系都生成单一钙钛矿相;x=0.0,0.6≤X≤1.0时为菱形晶系,0.2≤x≤0.5为立方晶系.IR和TPR研究表明,晶体结构对B—O键合作用存在较大影响.CO微反考察表明,本体系的催化活性与晶系存在密切关系,晶体对称性越高,反应活性越低.说明钙钛矿型复合氧化物的催化活性与体系活性中心的B—O键合作用能力有关. 相似文献
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季铵碱热消除反应常被认为遵循Hofmann规则,即倾向于生成最少烷基取代的乙烯。这种现象被解释为由于N的诱导,使与之结合的烷基的β-H酸性强弱有差别,β-H酸性强的烷基容易被消除。烷基是给电子诱导效应的基团,所以β-碳原子上被侧链烷基取代得越少,该碳原子上的β-H酸性越强。于是,反应的结果即主要形成最少烷基取代的乙烯。按这种理解的反应 相似文献
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Density functional theory and GGA-PW91 exchange correlation function were performed to simulate the bonding behavior of hydroxyl and epoxy groups on the graphene surface. We compared the different binding energies for two epoxy groups, as well as one hydroxyl group and one epoxy group on all possible positions within a 6-fold ring, respectively. The calculated results suggest that two oxygen-containing groups always tend to bind with the neighboring carbon atoms at the opposite sides. Moreover, two hydroxyl groups on the meta position are unstable, and one of the hydroxyl groups easily migrates to the para position. In contrast to the disperse arrangement, the aggregation of multiply hydroxyl groups largely enhances the binding energy of every hydroxyl group. It is worth noting that the binding sites and hydrogen bonds play an important role in stability. Our work further points out the number of oxygen-containing groups and the location of oxide region largely influence the electronic properties of graphene oxide. 相似文献
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Fabrication, Characterization and Electrocatalysis of an Ordered Carbon Nanotube Electrode 总被引:3,自引:0,他引:3
A method for fabrication of ordered carbon nanotube (CNT) film,which was template-synthesized within the highly ordered pores of a commercially available alumina template membrane,modified glassy carbon(CNT/GC) electrode was established.The CNT/GC electrode showed excellent electrocatalytic activity toward dopamine electrochemical reaction without introducing any electrochemically active group into CNT film or activating any electrochemically active group into CNT film or activating the electrode electrochemically.DA undergoes ideal reversible electrochemical reaction on CNT/GC electrode at low scan rate(≤20mV/s) with an excellent reproducibility and stability.The CNT/GC electrode might be used in biosensors because the highly ordered CNT may present a steric effect on more efficient redox reactions of biomolecules. 相似文献
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Inorganic crystalline solid electrolytes exhibit excep tional room-temperature ionic conductivities, giving them the potential to enable all-solid-state lithium (Li) - ion batteries. Developing new high-performance electrolytes is one of the most critical challenges to realize solid-state batteries, which requires understanding how chemistry facilitates fast ionic conduction and what the Li-ion migration mechanism is in in organic solid electrolytes. In this review, we aim to summarize recent fundamental research progress in Li-ion transport, including crystal structure, behavior of ion migration (i.e., single-ion jump and multi-ions cooperative migration), and the relationship between ion migration and microstructure. Generally, ion transport in crystalline structure can be categorized into vacancy and non-vacancy mechanism. For Li-ion conduction, the migration can be achieved through single-ion hopping and collective diffusion mechanism. For single-ion hopping mechanism, the diffusivity is determined by the depth of potential well (activation energy) and lattice dynamics;whereas in the later mechanism Li-ion moving from high potential to low potential could partially offset the energy required for Li-ion moving from low potential to high potential. By studying the collective diffusion from the perspective of local structures, it is believed that collective diffusion in fast ion conductor originates from the local 野dual Li-S/O冶 structure units, which can be characterized by the 野nearest Li-Li distance冶. Next, the paradigm of ion transport in solids is summarized. It is pointed out that most ion conductors follow Meyer-Neldel rule, where the activation energy and pre-exponential factor are mutual compensating. As a result, a balance should be adapted between these two values to achieve high Li-ion conductivity. However, for some fast ion conductors, the relationship does not follow the Meyer-Neldel rule (i.e., anti-Meyer-Neldel rule). Therefore, the physical significance of anti-Meyer-Neldel rule should be understood to develop next-generation lithium ion conductors. In the end, future perspectives and open questions are proposed to design and develop high-performance inorganic solid electrolytes. © 2021 Chinese Chemical Society. All rights reserved. 相似文献