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TiAl电子态结构的ab initio计算
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作者 张树东 王传航 +4 位作者 唐伟 孙阳 孙宁泽 孙召玉 徐慧 《物理学报》 SCIE EI CAS CSCD 北大核心 2019年第24期127-135,共9页
应用完全活动基自洽场方法,结合N电子价态微扰近似(NEVPT2),对TiAl金属二聚体的基态和若干最低电子激发态的势能曲线进行了计算.完全活动空间由Al的3个价电子(3s23p1)轨道和Ti的4个价电子(3d24s2)轨道构成,计算基组选用Karlsruhe group... 应用完全活动基自洽场方法,结合N电子价态微扰近似(NEVPT2),对TiAl金属二聚体的基态和若干最低电子激发态的势能曲线进行了计算.完全活动空间由Al的3个价电子(3s23p1)轨道和Ti的4个价电子(3d24s2)轨道构成,计算基组选用Karlsruhe group的价分裂全电子基组def2-n ZVPP(n=T,Q).在确认TiAl的基态为四重态的基础上,在核间距R=0.200-0.500 nm范围内,扫描获得了TiAl基态和最低二个激发态的完整势能曲线,并对电子态进行了标识,发现在0.255 nm附近存在电子态结构的"突变".在R>0.255 nm区域,基态和两个激发态分别为X^4Δ,A^4Π和B^4Γ;在R<0.255 nm区域,基态仍为X^4Δ,但两个激发态变为A’~4Φ和B’~4Π,且存在激发态简并解除的现象.基于NEVPT2修正后的势能曲线,获得了TiAl电子态的平衡核间距、束缚能、激发能、跃迁偶极矩等特征参数,并解释了实验上观测不到TiAl电子跃迁光谱的原因.电子激发态存在"突变"的结构特征,可为分析理解TiAl合金在室温下的脆性问题提供参考. 展开更多
关键词 TIAL 激发 势能曲线 完全活动基自洽场 N电子价态微扰近似
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AI、Nb在Nd_2Fe_(14)B晶体中的价态及对其磁性的影响
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作者 吴尚才 《广东有色金属学报》 1991年第2期142-146,共5页
本文研究了Al、Nb在Nd_2Fe_(14)B晶体中的价态及对其磁性的影响。结果表明:在Nd_2Fe_(14)B晶体中,具有较大结构体积的j_2晶位Fe原子[Fe(j_2)],由于受到近邻Nd的f电子的强烈作用,其d电子可以被“诱发”为磁电子,原子磁矩达3.4μ_B,比纯铁... 本文研究了Al、Nb在Nd_2Fe_(14)B晶体中的价态及对其磁性的影响。结果表明:在Nd_2Fe_(14)B晶体中,具有较大结构体积的j_2晶位Fe原子[Fe(j_2)],由于受到近邻Nd的f电子的强烈作用,其d电子可以被“诱发”为磁电子,原子磁矩达3.4μ_B,比纯铁的2.4μ_B大得多;Nb原子在晶体中置换j_2、k_1、k_2晶位上Fe原子时,它的d电子也可能成为磁电子;Al和Nb原子在Nd_2Fe_(14)B晶体价电子结构中,以无晶格电子的价态置换有晶格电子的Fe原子价态,导致硬磁性相各向异性的增强;Nb的两个4d价电子参加晶体的键合,增强了材料的磁温度稳定性。 展开更多
关键词 永磁材料 Nd_2Fe_14B 电子价态
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Dynamic pricing by hopfield neural network
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作者 Lusajo M Minga 冯玉强 +2 位作者 李一军 路杨 Kimutai Kimeli 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2004年第3期291-294,共4页
The increase in the number of shopbots users in e-commerce has triggered flexibility of sellers in their pricing strategies. Sellers see the importance of automated price setting which provides efficient services to a... The increase in the number of shopbots users in e-commerce has triggered flexibility of sellers in their pricing strategies. Sellers see the importance of automated price setting which provides efficient services to a large number of buyers who are using shopbots. This paper studies the characteristic of decreasing energy with time in a continuous model of a Hopfield neural network that is the decreasing of errors in the network with respect to time. The characteristic shows that it is possible to use Hopfield neural network to get the main factor of dynamic pricing; the least variable cost, from production function principles. The least variable cost is obtained by reducing or increasing the input combination factors, and then making the comparison of the network output with the desired output, where the difference between the network output and desired output will be decreasing in the same manner as in the Hopfield neural network energy. Hopfield neural network will simplify the rapid change of prices in e-commerce during transaction that depends on the demand quantity for demand sensitive model of pricing. 展开更多
关键词 E-COMMERCE dynamic pricing production function Hopfield neural network
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Multiple Ionic-Covalent Couplings in Molecules and Clusters
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作者 Gwang-Hi Jeung 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2009年第2期187-190,共4页
The electronic states of molecules made of electropositive and electronegative components result from the interference between the covalent configurations and the ionic configurations. This work shows complex aspects ... The electronic states of molecules made of electropositive and electronegative components result from the interference between the covalent configurations and the ionic configurations. This work shows complex aspects of these ionic-covalent couplings in small molecules such as Li2H, Li2F, and Li4F. The extension of this type of analysis to the adsorption of the electrophilic molecules on the metal clusters or on the metal surfaces is supposed to lead to a radically new interpretation of the observed physical and chemical properties. 展开更多
关键词 Surface adsorption Electron transfer Covalent configuration Ionic configuration Electronic state
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From Steady 4D Quantization of Valence Electrons to Material Space Paradigm
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作者 Igor E. Bulyzhenkov 《Journal of Chemistry and Chemical Engineering》 2013年第4期370-373,共4页
Potential electric and gravitational fields do not change steady quantized states of electrons in chemical bonds, microscopic clusters of charges and macroscopic superconducting rings. There are no theoretical grounds... Potential electric and gravitational fields do not change steady quantized states of electrons in chemical bonds, microscopic clusters of charges and macroscopic superconducting rings. There are no theoretical grounds to create Squid-type instruments to measure electric and gravitational fields with quantum accuracy basing on the Bohr-Sommerfeld quantization of charged particles. Squid-verified spatial flatness for superfluid electrons corresponds to the material space paradigm for reality. 展开更多
关键词 Continuous electron relativistic quantization.
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Crystal facet engineering of perovskite cobaltite with optimized electronic regulation for water splitting 被引量:1
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作者 Ya-Nan Zhou Feng-Ge Wang +3 位作者 Yi-Nuo Zhen Jun Nan Bin Dong Yong-Ming Chai 《Science China Materials》 SCIE EI CAS CSCD 2022年第10期2665-2674,共10页
The correlation between crystal facets and electronic configurations of perovskite is closely related to the intrinsic activity for water splitting.Herein,we proposed a unique molten-salt method(MSM)to manipulate the ... The correlation between crystal facets and electronic configurations of perovskite is closely related to the intrinsic activity for water splitting.Herein,we proposed a unique molten-salt method(MSM)to manipulate the electronic properties of LaCoO_(3) by fine-tuning its crystal facet and atomic doping.LaCoO_(3) samples with oriented(110)(LCO(110))and(111)(LCO(111))facets were motivated by a capping agent(Sr^(2+)).Compared with the LCO(111)plane,the LCO(110)and Sr-doped LCO(111)(LSCO(111))planes possessed higher O 2p positions,stronger Co 3d-O 2p covalencies,and higher Co spin states by inducing CoO_(6) distortion,thus leading to superior oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)performances.Specifically,the overpotentials at 10 mA cm^(−2) were 299,322,and 289 mV for LCO(110),LCO(111),and LSCO(111),respectively.In addition,the(110)crystal facet and Sr substitution bestowed enhanced stability on LaCoO_(3) due to the strengthened Co-O bonding.The present work enlightens new avenues of regulating electronic properties by crystal facet engineering and atom doping and provides a valuable reference for the electron structure-electrocatalytic activity connection for OER and HER. 展开更多
关键词 electronic structure crystal facet engineering Sr doping LaCoO_(3) water splitting
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