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云上异构数据库管理技术(dms)研究

移动信息 2024年第4期46卷 335-338页

作者：刘旭武梦娟冯义磊井长军李嘉怡北京中电普华信息技术有限公司北京100192

为了解决企业中因国产数据库及国外数据库等异构数据库增多而带来的管理难度增加、运维成本高涨等问题,文中基于云服务的异构数据库管理(dms),采用了Web模式。其提供了异构数据库对象研究、异构数据库SQL脚本兼容、异构数据库SQL执行分... 详细信息

为了解决企业中因国产数据库及国外数据库等异构数据库增多而带来的管理难度增加、运维成本高涨等问题,文中基于云服务的异构数据库管理(dms),采用了Web模式。其提供了异构数据库对象研究、异构数据库SQL脚本兼容、异构数据库SQL执行分析、异构数据库SQL结果展示及审计等能力,解决了当前数据库管理工具良莠不齐,存在费用高、安装困难、部署耗时、难上手的问题,致力于帮助企业高效、安全的挖掘数据价值,助力企业数字化转型。

关键词： dms 异构数据库 AST 解析树数据可视化

First-principles prediction of the magnetism of 4f rare-earth-metal-doped wurtzite zinc oxide

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Journal of Rare Earths 2014年第8期32卷 715-721页

作者： A.G.El Hachimi H.Zaari A.Benyoussef M.El Yadari A.El Kenz Laboratoire de Magnétisme et Physique des Hautes Energies LMPHE (URAC 12) Département de Physique B.P.1014 Faculté des SciencesUniversité Mohammed V-Agdal Institut of Nanomaterials and Nanotechnology Hassan II Academy of Science and Technology Department of Science Moulay Ismail University Faculté Polydisciplinaire

Electronic structure and magnetic properties of wurtzite ZnO semiconductor doped with rare earth （RE=La, Ce, Pr, Pm, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb） atoms were studied using spin-polarized density functional theory based on the full-potential linear augmented plane wave （FP-LAPW） method as implemented in the Wien2k code. In this approach the generalized gradient approximation （GGA） was used for the exchange-correlation （XC） potential. Our results showed that the substitution of RE ions in ZnO induced spins polarized localized states in the band gap. Moreover, the studied dmss compounds retained half metallicity at dopant concentration x=0.625%for most of the studied elements, with 100%spin polarization at the Fermi level （EF）. The total magnetic moments of these compounds existed due to RE 4f states present at EF, while small induced magnetic moments existed on other non-magnetic atoms as well. Finally, the energy difference between far and near configurations was investigated. It was found that the room temperature ferromagnetism was possible for RE-doped ZnO at near configuration. Since the RE-RE separation was long enough （far configuration） for magnetic coupling, the system became paramagnetic or antiferromagnetic ground state.

关键词： ZnO rare earths ferromagnetism dms electronic structure magnetic properties half-metallic RE-doped ZnO FP-LAPW method density functional theory

海洋细菌粪产碱菌J481中dms趋化受体的鉴定

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微生物学报 2022年第12期62卷 5029-5042页

作者：赵丽君谢珂杨江科雷磊武汉轻工大学生命科学与技术学院湖北武汉430023

【目的】β-二甲基巯基丙酸(β-dimethylsufoniopropionate,dmsP)是海洋环境中重要的含硫有机化合物,会被海洋中的微生物裂解并释放出挥发性气体二甲基硫醚(dimethylsulfide,dms)。该反应的生物学意义尚不明确,前人曾有少量研究表明dms... 详细信息

【目的】β-二甲基巯基丙酸(β-dimethylsufoniopropionate,dmsP)是海洋环境中重要的含硫有机化合物,会被海洋中的微生物裂解并释放出挥发性气体二甲基硫醚(dimethylsulfide,dms)。该反应的生物学意义尚不明确,前人曾有少量研究表明dmsP可能是趋化效应物。本研究旨在鉴定dmsP趋化作用中的信号分子以及该过程中的趋化受体基因。【方法】挖掘出基因组中含有甲基趋化受体蛋白结构域(methyl-accepting chemotaxis protein,MCP)的全部基因,并预测趋化受体蛋白的结构特征及功能。通过同源重组构建所有趋化受体的缺失突变株,并通过软琼脂平板实验观察趋化表型确定dms的趋化受体。【结果】对不同化合物dmsP、dms、丙烯酸进行鉴别后,明确趋化信号分子为dms。从粪产碱菌(Alcaligenes faecalis)J481基因组中一共挖掘到8个潜在编码趋化受体蛋白的基因,分别构建对应的缺失突变株,并通过实验筛选出D6I95_17420基因为编码识别dms的趋化受体蛋白基因。【结论】D6I95_17420基因为编码dms的趋化受体蛋白的基因,为之后进一步阐明dms作为信号分子在细胞内的调控作用奠定了基础。

关键词：粪产碱菌J481 基因组挖掘 dms 趋化作用信号转导

First Principle Study of Ferromagnetism in Cr-Doped In_2O_3

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Chinese Journal of Structural Chemistry 2008年第8期27卷 907-914页

作者：谢知程文旦吴东升黄淑萍胡建明张浩胡慧 State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter The Chinese Academy of SciencesFuzhou Fujian 350002 China

We present a first principle study of Cr-doped In2O3 system using density functional theory. The obtained results show that the Cr ion prefers the cation site of the center of trigonally distorted octahedron and converges to high spin-polarized configuration in the ground state. The hybridization between d-states and the donor states is strong, and the spin-split donor impurity-band model is found to be the most favorable mechanism for the ferromagnetism in this system. The good ferromagnetic property of high Curie temperature is discussed in view of the electronic structure analyses.

关键词： dms ferromagnetism Curie temperature In2O3 first-principle DFT

Microstructural properties of over-doped GaN-based diluted magnetic semiconductors grown by MOCVD

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Journal of Semiconductors 2012年第7期33卷 16-19页

作者：陶志阔张荣修向前崔旭高李丽李鑫谢自力郑有炓郑荣坤 Simon P Ringer Key Laboratory of Advanced Photonic and Electronic Materials School of Electronic Science and EngineeringNanjing University College of Electronic Science and Engineering Nanjing University of Posts and Telecommunications Australia Key Center for Microscopy and Microanalysis University of Sydney

We have grown transition metal （Fe, Mn） doped GaN thin films on c-oriented sapphire by metal-organic chemical vapor deposition. By varying the flow of the metal precursor, a series of samples with different ion con- centrations are synthesized. Microstructural properties are characterized by using a high-resolution transmission electron microscope. For Fe over-doped GaN samples, hexagonal Fe3N clusters are observed with Fe3N （0002） parallel to GaN （0002） while for Mn over-doped GaN, hexagonal Mn6N2.58 phases are observed with Mn6N2.58（0002） parallel to GaN （0002）. In addition, with higher concentration ions doping into the lattice matrix, the partial lattice orientation is distorted, leading to the tilt orGaN （0002） planes. The magnetization of the Fe over-doped GaN sam- ple is increased, which is ascribed to the participation of ferromagnetic iron and Fe3N. The Mn over-doped sample displays very weak ferromagnetic behavior, which probably originates from the Mn6N2.58.

关键词： MOCVD dms high-resolution TEM

Resource allocation in downlink OFDMA distributed multipoint systems with incoherent and coherent transmitters

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The Journal of China Universities of Posts and Telecommunications 2011年第3期18卷 62-68页

作者： WANG Tan WANG Ying ZHANG Ping Wireless Technology Innovation Institute Key Laboratory of Universal Wireless Communication Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

Distributed multipoint systems （dms） are important and timely for the move to future broadband wireless communication systems. Traditional studies on dms have mainly focused on the issues with the spatial division multiple access such as precoding techniques, which only consider a narrowband case. This paper addresses the downlink radio resource management of the orthogonal frequency division multiple access dms （OFDMA-dms）, including power allocation between users or subcarriers, and distributed antenna selection. Signal models with incoherent and coherent transmitters are built. To maximize the system throughput, for the incoherent transmitter case, a strategy based on the iterative water-filling power allocation is proposed to approach the optimality. As for the coherent case, where coherent additions of the signal could occur at the users, the problem is transformed into an integer programming which is solvable. Numerical results show that the gain from the coherent transmitter is promising. And to achieve a near-optimal solution, only part of the DA ports will be used, which have better channel conditions.

关键词： dms orthogonal frequency division multiple access （OFDMA） power allocation antenna port selection

Distribution management system framework based on security region for future low carbon distribution systems

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Journal of Modern Power Systems and Clean Energy 2015年第4期3卷 544-555页

作者： Jun XIAO Qibo HE Guoqiang ZU Key Laboratory of Smart Grid of Ministry of Education Tianjin UniversityTianjinChina

In this paper,a new Distribution Management System(dms)framework based on security region is proposed.First,the concept of Distribution System Security Region(DSSR)is introduced.DSSR is capable to describe the N-1 security boundary of the whole distribution network,including the secure output range of DGs.This new theoretic tool provides a chance for the implementation of real-time security analysis and active controls in dms.Second,this paper proposes and describes five security states for distribution system.Third,an upgraded dms enhanced with DSSR is proposed,which consists of advanced security functions such as preventive and predictive control of the trajectory of operating points.Finally,a practical case is presented to simulate the proposed DSSR-enhanced dms,in which both the security region of network and the output range of DGs are calculated.Typical security functions are also demonstrated.In conclusion,the new dms framework aims to help operate the system closed to its security boundary in order to improve the efficiency significantly within same security standard.This work is beneficial for future low carbon distribution systems with high penetration rate of DGs.

关键词： dms Security region N-1 security Distributed generation Preventive control Low carbon

First-principle Calculations of V/Fe Doped Anatase TiO_2

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Chinese Journal of Aeronautics 2006年第B12期19卷 162-166页

作者： CAO Hong-hong CHEN Qiang WANG Tian-min School of Science Beijing University of Aeronautics and Astronautics Beijing 100083 China

The electronic structures of the titanium dioxide（TiO2） doped with V and Fe were analyzed by using first-principle calculations based on the density functional theory（DFT） with the full potential linearized augmented plane wave method （FP-LAPW）. The fully optimized structure and the relaxation introduced by impurity were obtained by minimizing the total energy and atomic forces. The unit cell of the V-doped anatase TiO2 is smaller than that of the non-doped one, but for the Fe-doped one, the case is just the opposite. It is found that the apical Ti-O and impurity-O bond lengths of the V/Fe-doped anatase TiO2 are greater than those of the non-doped structure, but smaller for the equatorial bond length. Through the band structures and the density of states, the V-doped TiO2 is shown to be a kind of half-metal, while the Fe-doped TiO2 a kind of metal. The magnetic moments of the V/Fe-doped system are mainly generated by the dopants. The results may be helpful for us to understand the experimental outcome of this system.

关键词： first-principle FP-LAPW dms anatase electronic properties

MSA in Beijing aerosol

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Chinese Science Bulletin 2004年第10期49卷 1020-1025页

作者： YUANHui WANGYing ZHUANGGuoshun TheCenterforAtmosphericEnvironmentalStudy.BeijingNormalUniversity Beijing100875China LAPC TheInstituteofAtmosphericPhysics.ChineseAcademyofSciences.Beijing100029China

Methane sulphonate (MSA) and sulfate (SO4^2-),the main oxidation products of dirnethyl sulfide (dms), arethe target of atmospheric chemistry study, as sulfate aerosolwould have important impact on the global climate change. It is widely believed that dms is rnainly emitted from phyto-plankton production in marine boundary layer (MBL), andmsA is usually used as the tracer of non-sea-salt sulfate (nss-SO4^2-) in marine and coastal areas/MSA/SO4^2- = 1/18) Manyobservations of MSA were in marine and coastal aerosols. Toour surprise, MSA was frequently (＞60%) deteeted in BeijingTSP. PM10, and PM2.5 aerosols, even in the samples collectedduring the dust storm period. The concentrations of MSAwere higher than those measured in marine aerosols. Factoranalysis, correlation analysis and meteorology analysis indi-cated that there was no obvious marine influence on Beljiagaerosols. dms from terrestrial emissions and dimethyl sulphoxide (dmsO) from industrial wastes could be the twopossible precursors of MSA. Warm and low-pressure airmasses and long time radiation were beneficial to the forma-tion of MSA. Anthropogenlc pollution from regional andlocal sources might be the dominant contributor to MSA inBeijing aerosol. This was the first report of MSA in aerosolscollected in an inland site in China. This new finding wouldlead to the further study on the balance af sulfur in inlandcities and its global bingcoehemical cycle.

关键词： MSA 磺酸甲烷 dms 二甲基硫醚二甲基亚砜硫酸盐气溶胶北京大气化学