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A Group Oriented Cryptosystem for the Vector Space Access Structure
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作者 许春香 马华 +1 位作者 周军会 肖国铮 《Journal of Shanghai Jiaotong university(Science)》 EI 2006年第2期184-187,共4页
A group oriented cryptosystem for the vector space access structure was proposed. This cryptosystem adopts self-certified public keys. It allows the participants of an authorized subset to cooperatively access an encr... A group oriented cryptosystem for the vector space access structure was proposed. This cryptosystem adopts self-certified public keys. It allows the participants of an authorized subset to cooperatively access an encrypted message. All data delivered in the cryptosystem are public. Therefore it does not need a partial decrypting results combiner and any secure communication channel. The security of the group oriented cryptosystem is based on the intractability of the discrete log problem and difficulty of factoring large integers. The suspected attacks can not break it. 展开更多
关键词 group oriented cryptosystems sell-certified public keys vector space access structure
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Strong convergence theorems for nonexpansive semi-groups in Banach spaces 被引量:2
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作者 张石生 杨莉 柳京爱 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2007年第10期1287-1297,共11页
Some strong convergence theorems of explicit composite iteration scheme for nonexpansive semi-groups in the framework of Banach spaces are established. Results presented in the paper not only extend and improve the co... Some strong convergence theorems of explicit composite iteration scheme for nonexpansive semi-groups in the framework of Banach spaces are established. Results presented in the paper not only extend and improve the corresponding results of ShiojiTakahashi, Suzuki, Xu and Aleyner-Reich, but also give a partially affirmative answer to the open questions raised by Suzuki and Xu. 展开更多
关键词 nonexpansive semi-group demi-closed principle common fixed point uni-formly smooth Banach space weakly continuous normalized duality mapping
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3D Braided Material Based on Space Group <i>R</i>3 Symmetry
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作者 Wensuo Ma Dongdong Yin 《Materials Sciences and Applications》 2013年第12期773-779,共7页
A unit cell geometrical structure was found with the use of symmetry operations corresponding to the point group C3. Based on the symmetry of space group R3, a 3D braided geometrical structure was obtained by transfor... A unit cell geometrical structure was found with the use of symmetry operations corresponding to the point group C3. Based on the symmetry of space group R3, a 3D braided geometrical structure was obtained by transforming the unit-cell. The features corresponding to this braided structure were studied. The fiber volume percentage and variational tendencies of the material were predicted by establishing a geometric model. 展开更多
关键词 Point group C3 space group R3 3D Braided GEOMETRICAL structure
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Endpoints of Multi-Valued Weak Contractions on the Metric Space of Partially Ordered Groups
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作者 Congdian Cheng 《Advances in Pure Mathematics》 2022年第11期638-651,共14页
The present work considers the endpoint in the abstract metric space. It firstly introduces the metric space of partially ordered groups and the metric space of partially ordered modules, respectively;and defines the ... The present work considers the endpoint in the abstract metric space. It firstly introduces the metric space of partially ordered groups and the metric space of partially ordered modules, respectively;and defines the convergence of sequences and the multi-valued weak contractions, etc., on the introduced space. And then, with the methods of functional analysis and abstract algebra, it successively establishes an endpoint theorem for the metric space of partially ordered groups and an endpoint theorem for the metric space of partially ordered modules. The contributions of this article extend the theory of cone metric space constructed by Huang and Zhang (2007) and some recent results on the fixed point and endpoint theory, such as the endpoint theorem given by Amini-Harandi (2010). 展开更多
关键词 Fixed Point Endpoint Metric space Valued in Partially Ordered group Topological structure Weak Contraction
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ON THE RELATIONSHIP BETWEEN THE TYPES OF SPACE GROUPS OF HIGH-TEMPERATURE PHASE AND LOW-TEMPERATURE PHASE AND THE NATURE OF DOMAIN STRUCTURE FOR PHASE TRANSITIONAL MINERAL
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作者 徐洪武 杨南如 薛纪越 《Chinese Science Bulletin》 SCIE EI CAS 1992年第4期321-324,共4页
Recently, with the increasing use of TEM technique in mineralogy, more and more space groups of high-temperature phases and low-temperature phases and the domain structures of phase transitional minerals have been det... Recently, with the increasing use of TEM technique in mineralogy, more and more space groups of high-temperature phases and low-temperature phases and the domain structures of phase transitional minerals have been determined. Therefore, on the basis of summarizing the numerous results of individual minerals, it is necessary to discuss the relationship between the types of space groups of two phases and the nature of 展开更多
关键词 MINERAL CRYSTAL phase TRANSITION the type of space group DOMAIN structure
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Overgroups in GL (nr, F) of TU (n, K, h) or Ω (n, K Q)
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作者 李尚志 《Chinese Science Bulletin》 SCIE EI CAS 1994年第3期182-185,共4页
Let K, F be division rings, with KF,and dim_F K=r【∞ when we regard K asa left F-space. An n-dimensional left K-space V(n, K) can be regarded as annr-dimensional left space V= V(nr,F) over F,and thus GL (n, K) acting... Let K, F be division rings, with KF,and dim_F K=r【∞ when we regard K asa left F-space. An n-dimensional left K-space V(n, K) can be regarded as annr-dimensional left space V= V(nr,F) over F,and thus GL (n, K) acting on V(n, K)is embedded in GL (nr, F) acting on V (nr, F). In Ref. [1] we determined theovergroups of SL (n, K) and Sp (n, K) in GL(nr,F), Which are precisely the lineargroups or symplectic groups acting on the vector spaces structure V (nd, E) 展开更多
关键词 classical groupS OVER DIVISION RINGS groupS OVER DIVISION extension RINGS overgroups vector space structures OVER intermediate DIVISION RINGS maximal subgroups.
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Group theory analysis of braided geometry structures 被引量:1
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作者 FENG Wei MA Wensuo 《Chinese Science Bulletin》 SCIE EI CAS 2005年第21期2529-2533,共5页
The braided geometry structures are analyzed with point groups and space groups for which the continuous yarn of the braided preforms is segmented and expressed in some special symbols. All structures of braided mater... The braided geometry structures are analyzed with point groups and space groups for which the continuous yarn of the braided preforms is segmented and expressed in some special symbols. All structures of braided material are described and classified with group theory, and new braiding methods are found. The group theory analysis lays the theo-retical foundation for optimizing material performance. 展开更多
关键词 几何结构 群理论 空间群 半群
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碳族单质超导性的第一性原理研究
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作者 韩沛辰 林永熠 +3 位作者 郑磊 刘其军 刘正堂 高娟 《原子与分子物理学报》 CAS 北大核心 2025年第4期87-92,共6页
同为第四主族的元素,碳、硅、锗、锡、铅具有相似的价电子排布,但超导性却并不相同.锡和铅在常压下即可实现超导,硅和锗则需要在高压下才具有超导性,而碳的常规晶体结构在常压和高压下均尚未发现其超导性.压力在很大程度上是通过改变晶... 同为第四主族的元素,碳、硅、锗、锡、铅具有相似的价电子排布,但超导性却并不相同.锡和铅在常压下即可实现超导,硅和锗则需要在高压下才具有超导性,而碳的常规晶体结构在常压和高压下均尚未发现其超导性.压力在很大程度上是通过改变晶体结构和原子之间的位置进而影响其超导性,本论文基于密度泛函理论的第一性原理计算,对碳、硅、锗、锡、铅五种第四主族元素的单质的晶体结构、电子结构、声子性质以及超导性质进行系统地对比分析.计算结果表明费米能级附近的电子态密度越高,金属体系实现超导所需的压力越小.在具有金属性的体系中价带靠近费米能级处带隙的存在会使电子更容易局域在费米能级附近,从而增大费米能级附近电子态的数目并提高体系的超导性.此研究为探究超导机制并提高材料的超导性提供思路. 展开更多
关键词 超导性 第一性原理计算 碳族元素 电子结构
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Crystal Structure of Natural Non-metamict Ti- and Fe^(2+)-rich Chevkinite-(Ce) 被引量:1
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作者 LIGuowu YANGGuangming +4 位作者 MAZhengsheng SHINicheng XIONGMing FANHaifu SHENGGanfu 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2005年第3期325-331,共7页
The crystal structure of non-metamict Ti- and Fe2+-rich chevkinite-(Ce) has been redetermined with the single -crystal sample collected from Bayan Obo, Inner Mongolia, China. The chemical formula of the sample is Ce4F... The crystal structure of non-metamict Ti- and Fe2+-rich chevkinite-(Ce) has been redetermined with the single -crystal sample collected from Bayan Obo, Inner Mongolia, China. The chemical formula of the sample is Ce4Fe2Ti3Si4O22. The crystals are monoclinic with the unit cell parameters a = 13.4656(15) ?, b = 5.7356(6) ?, c = 11.0977(12) ?, β= 100.636(2)o, V = 842.39 (16) ?3 and Z = 2. The structures of Ti- and Fe2+-rich chevkinite-(Ce) were refined with space groups P21/a and C2/m. Least-squares refinement results show that both structural models of Ti- and Fe2+-rich chevkinite-(Ce) are very good, R[F2>2σ(F2)] =0.027 with P21/a and R[F2>2σ(F2)] =0.021 with C2/m. In order to illustrate the relationship between the two space groups P21/a and C2/m, the distribution of diffraction intensities was inspected. Pseudo extinction was found, i.e., reflections with h+k=2n are systematically strong, while those with h+k=2n+1 are weak. By neglecting the systematically weak (h+k=2n+1) reflections the space group becomes C2/m. There is a mirror plane in the C2/m perpendicular to the b axis. However, oxygen atoms in the P21/a model are of a symmetrical relationship with the corresponding pseudo mirror plane. It is concluded that the crystal structure of non-metamict Ti- and Fe2+-rich chevkinite-(Ce) is a superstructure with the space group of P21/a, which is of pseudo symmetry corresponding to the space group C2/m. 展开更多
关键词 non-metamict Ti- and Fe2+-rich chevkinite-(Ce) crystal structure space group superstructure
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A New Version of Unified Field Theory—Stochastic Quantum Space Theory on Particle Physics and Cosmology 被引量:3
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作者 Zhi-Yuan Shen 《Journal of Modern Physics》 2013年第10期1213-1380,共168页
Stochastic Quantum Space (SQS) theory is a new version of unified field theory based on three fundamental postulations: Gaussian Probability Postulation, Prime Numbers Postulation, Vacuon Postulation. It build a frame... Stochastic Quantum Space (SQS) theory is a new version of unified field theory based on three fundamental postulations: Gaussian Probability Postulation, Prime Numbers Postulation, Vacuon Postulation. It build a framework with theoretical results agree with many experimental data well. For more information, please refer to the PDF. 展开更多
关键词 Unified Field THEORY space structure Elementary Particles Gaussian Probability Prime Numbers SPORADIC groups GUT DARK Matter DARK Energy Cosmos INFLATON MULTIVERSE Anthropic principle General Relativity Primary Basic Equations
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扩底桩竖向承载特性及群桩效应研究 被引量:2
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作者 邓友生 吴阿龙 +3 位作者 陈茁 庄子颖 肇慧玲 董晨辉 《铁道建筑》 北大核心 2024年第2期107-111,共5页
为探明扩底群桩竖向承载特性,采用扩底桩筏结构,开展单桩(扩径比分别为1.5、2.0、2.5、3.0)和桩筏(扩径比为2)基础静载模型试验,分析其荷载传递规律,并建立桩间距为3.75、4.00、4.50、5.00倍桩直径时扩底桩筏基础有限元模型,研究桩间距... 为探明扩底群桩竖向承载特性,采用扩底桩筏结构,开展单桩(扩径比分别为1.5、2.0、2.5、3.0)和桩筏(扩径比为2)基础静载模型试验,分析其荷载传递规律,并建立桩间距为3.75、4.00、4.50、5.00倍桩直径时扩底桩筏基础有限元模型,研究桩间距对群桩效应影响。结果表明:扩底单桩和扩底桩筏结构荷载沉降曲线均为缓变型;扩底桩极限承载力随扩径比增大而逐渐增大,扩径比2.5~3.0时极限承载力增幅变缓,建议扩底桩扩径比取2.5~3.0;由于桩土共同沉降,桩间土压缩,桩土作用更充分,扩底桩筏基础中心桩侧摩阻力荷载分担比比扩底单桩增大了17.71%;群桩效应系数随桩间距增大而逐渐增大,桩间距为4.5~5.0倍桩直径时群桩效应系数增幅较小,群桩效应较弱,建议扩底桩筏基础桩间距取值不小于4.5倍桩直径。 展开更多
关键词 扩底桩筏结构 模型试验 承载特性 群桩效应 扩径比 桩间距
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“钢结构设计原理”课程教学新模式的探索与实践
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作者 余志祥 陈景鑫 张明 《教育教学论坛》 2024年第15期81-84,共4页
为响应《关于深化本科教育教学改革全面提高人才培养质量的意见》,提高本科教学质量,教学课题组探索了“钢结构设计原理”课程教学的新模式,即以线下教学为主,结合线上直播授课、网络教学平台以及QQ交流群内讨论答疑的方式开展课程教学... 为响应《关于深化本科教育教学改革全面提高人才培养质量的意见》,提高本科教学质量,教学课题组探索了“钢结构设计原理”课程教学的新模式,即以线下教学为主,结合线上直播授课、网络教学平台以及QQ交流群内讨论答疑的方式开展课程教学,在尽可能给予学生最好的课堂学习体验的同时,也为他们提供优质的课后学习资料。线上与线下并行、理论与实践结合是该新模式探索的关键。此外,引入钢结构工程中蕴含的丰富的思政元素,综合提升学生的专业知识与思想品德素养。 展开更多
关键词 本科教学新模式 钢结构设计原理 线上与线下并行教学 网络教学平台 QQ交流群
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二维MXene材料CrVCF_(2)的电子性质和磁性的第一性原理研究
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作者 刘晓莹 黄海深 +2 位作者 孙丽 潘孟美 尚真真 《人工晶体学报》 CAS 北大核心 2024年第8期1386-1393,共8页
采用基于密度泛函理论的第一性原理研究了—F官能团对Janus型MXene二维材料CrVC的结构、电子性质和磁性的影响。计算结果表明,—F官能团改变了CrVC的电子性质和磁性,CrVCF_(2)的9种可能结构的基态是铁磁态,其中CrVCF_(2)-33结构的能量最... 采用基于密度泛函理论的第一性原理研究了—F官能团对Janus型MXene二维材料CrVC的结构、电子性质和磁性的影响。计算结果表明,—F官能团改变了CrVC的电子性质和磁性,CrVCF_(2)的9种可能结构的基态是铁磁态,其中CrVCF_(2)-33结构的能量最低,是最为稳定的基态结构,其磁矩为5.01μ_(B),带隙为0.099 eV,具有半导体特性。在施加-4%~+4%的双轴拉伸与压缩应变时,CrVCF_(2)-33的总磁矩保持不变;能量随着压缩或拉伸应变的增大而变大,但变化的幅度低于0.2 eV;带隙在应变的作用下会发生改变,当拉伸应变为2.4%时,带隙减小到0.005 eV,接近于零,可看作是自旋零带隙半导体。由此可知,适度的应变可调节CrVCF_(2)材料的电子能带结构,甚至可形成自旋零带隙半导体,这在自旋电子学领域具有潜在的应用价值。 展开更多
关键词 第一性原理 MXene材料 —F官能团 电子结构 磁性 应变
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VI族元素修饰对二维AlN电子性质影响的第一性原理研究
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作者 莫秋燕 欧满琳 +2 位作者 张颂 荆涛 吴家隐 《人工晶体学报》 CAS 北大核心 2024年第9期1620-1628,共9页
采用密度泛函理论的第一性原理计算方法,研究了VI族元素(O、S、Se、Te)修饰对二维AlN电子性质的影响。计算结果表明,O修饰后,二维AlN体系的能带发生劈裂,从而转变为磁性材料;S、Se和Te修饰后,二维AlN电子态密度曲线自旋向上和自旋向下... 采用密度泛函理论的第一性原理计算方法,研究了VI族元素(O、S、Se、Te)修饰对二维AlN电子性质的影响。计算结果表明,O修饰后,二维AlN体系的能带发生劈裂,从而转变为磁性材料;S、Se和Te修饰后,二维AlN电子态密度曲线自旋向上和自旋向下完全对称,形成了非磁性结构。从态密度图可以看出,费米能级附近的态密度主要由修饰原子的p态电子和N原子的p态电子贡献,导带底部逐渐向低能区移动,导致二维AlN的吸收波长阈值从紫外线区域向可见光移动。因此,修饰的二维AlN光催化效率提高,并有应用于可见光响应的光电子和自旋电子器件的可能。 展开更多
关键词 二维AlN VI族元素 修饰 第一性原理 电子结构 磁性
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配位聚合物{[Zn(CF_3COO)_2(C_5H_5ON)·]H_2O}_n的合成、晶体结构及表征 被引量:8
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作者 马卫兴 高健 +5 位作者 钱保华 许兴友 陆路德 杨绪杰 汪信 宋海斌 《无机化学学报》 SCIE CAS CSCD 北大核心 2005年第5期749-752,共4页
new coordination polymer {[Zn(CF3COO)2(C5H5ON)]·H2O}n was synthesized based on the reaction of zinc(Ⅱ) trifluoroacetate and 3-hydroxypyridine(C5H5ON) in methanol medium for the first time. The structure of the c... new coordination polymer {[Zn(CF3COO)2(C5H5ON)]·H2O}n was synthesized based on the reaction of zinc(Ⅱ) trifluoroacetate and 3-hydroxypyridine(C5H5ON) in methanol medium for the first time. The structure of the coordination polymer was confirmed by IR, 1H NMR, elemental analysis and thermal analysis. The crystal structure of the coordination polymer was also determined by X-ray single crystal diffraction. The crystal belongs to monoclinic system with space group P21/m, and crystallographic data of the coordination polymer are: a= 0.863 1(4) nm, b=0.717 7(3) nm, c=1.116 4(5) nm, α=γ=90°, β=107.542(6)°, V=0.659 4(5) nm3; Dc=2.037 g·cm-3; Z=2; F(000)=400; μ=1.969 mm-1. Zinc(Ⅱ) atom lies at the center of an octahedron formed by the coordination of zinc atom and six O atoms which come from four different trifluoroacetate ions and two different 3-hydroxypyridine molecules where each trifluoroacetate ion and 3-hydroxypyridine are coordinated to two different zinc ions to form coordination polymer. CCDC: 253909. 展开更多
关键词 配位聚合物 晶体结构 crystal analysis 合成 表征 ZINC system center ATOM the and first space group WHERE was The with data ZINC form poly are new ^1H NMR ion IR
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草酸根桥联的双核铜髤配合物[Cu_2(phen)_2(H_2O)_2(μ_2-C_2O_4)](NO_3)_2的合成及晶体结构 被引量:7
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作者 卢文贯 潘育方 彭翠红 《无机化学学报》 SCIE CAS CSCD 北大核心 2005年第5期709-712,共4页
A new binuclear copper(Ⅱ) complex, [Cu2(phen)2(H2O)2( μ2-C2O4)](NO3)2, has been synthesized and characterized by elemental analysis, IR and UV-Vis spectrum. Its crystal structure was determined by single crystal X-r... A new binuclear copper(Ⅱ) complex, [Cu2(phen)2(H2O)2( μ2-C2O4)](NO3)2, has been synthesized and characterized by elemental analysis, IR and UV-Vis spectrum. Its crystal structure was determined by single crystal X-ray diffraction techniques. Crystal data: monoclinic, space group P21/c, a=0.712 21(8) nm, b=1.170 93(14) nm, c=1.783 7(2) nm, β=111.828(2)°, and V=1.380 8(3) nm3, Dc=1.769 Mg·m-3, Z=2, F(000)=744, R1=0.025 4, wR2=0.069 5, Gof=1.077, Δρ=328^-455 e·nm-3. The complex is packed by one centrosymmetry binuclear copper(Ⅱ) unit, oxalate dianion and NO3- anion. In the molecule structure of the title complex, two Cu(Ⅱ) ions are bridged by oxalate dianion and each Cu(Ⅱ) ions coordinates with two nitrogen atoms from 1,10-phenanthroline ligand and one oxygen atom from water to form a five-coordinate distorted square-pyramidal configuration. The hydrogen bonds are observed between coordinated water molecules and NO3- anions. The analysis of the crystal structure indicates that the complex has a two-dimensional stacking network structure, which is formed by intramolecular hydrogen bonds, intermolecular hydrogen bonds and stacking effect of aromatic ring. CCDC: 255345. 展开更多
关键词 双核铜(Ⅱ)配合物 草酸根桥联 晶体结构 complex analysis CRYSTAL CRYSTAL network NO3^- Cu(Ⅱ) 合成 UV-VIS and spect space group the The data unit with ATOM form one are new Its was ani IR
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弱桥联二聚体丙酮酸异烟酰腙合锡(Ⅳ)配合物[(p-CNC_6H_4CH_2)_2Sn(C_9H_7N_3O_3)(H_2O)]_2的合成、表征和晶体结构 被引量:2
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作者 尹汉东 洪敏 +1 位作者 薛绳才 王大奇 《无机化学学报》 SCIE CAS CSCD 北大核心 2005年第7期1073-1076,共4页
Diorganotin(Ⅳ) compound [(p-CNC6H4CH2)2Sn(C9H7N3O3)(H2O)]2 was synthesized by the reaction of tri-p-cyanobenzyltin chloride with Schiff base ligand pyruvic acid isonicotinyl hydrazone. The compound was characterized ... Diorganotin(Ⅳ) compound [(p-CNC6H4CH2)2Sn(C9H7N3O3)(H2O)]2 was synthesized by the reaction of tri-p-cyanobenzyltin chloride with Schiff base ligand pyruvic acid isonicotinyl hydrazone. The compound was characterized by elemental analysis, IR, 1H NMR. The crystal structure was determined by X-ray single crystal diffraction. The crystal belongs to monoclinic space group C2/c, with a=3.143 1(3) nm, b=0.989 99(10) nm, c=1.785 68(18) nm, β=114.908 0(13)°, V=5.039 6(9) nm3, Z=4, μ=1.054 mm-1, Dc=1.513 Mg·m-3, F(000)=2 304, R=0.042 8, wR=0.090 3, GOF=0.997. In this compound, the Sn atom exists in a distorted octahedral coordination environment in which one water molecule, one tridentate pyruvic acid isonicotinyl hydrazone ligand, and two trans p-cyanobenzyl groups coordinate to each Sn center, the angle of the axial C10-Sn1-C18 is 166.1(2)°. Two molecules form a weak-bridged dimmer with weak interactions of Sn...O bonding and hydrogen bonds. CCDC: 270796. 展开更多
关键词 锡(Ⅳ) 异烟酰腙 晶体结构 crystal 配合物 丙酮酸 二聚体 analysis bonding 合成 桥联 表征 with center acid space group the was The atom form one and ^1H Sn IR
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紧致齐性空间G/T上复结构的若干性质
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作者 杜材煜 王瑜 《兰州理工大学学报》 CAS 北大核心 2024年第3期167-172,共6页
设G为连通单连通s阶实幂零李群,且其上有左不变可积近复结构J,T为李群G的最大秩的格;考虑紧致齐性空间G/T上是否有幂零复结构;运用归纳法证明了复结构J可诱导出紧致齐性空间G/T的可积复结构J且是幂零的.
关键词 连通单连通幂零李群 左不变可积近复结构 幂零复结构 紧致齐性空间
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米仓山西段地质研究新进展 被引量:12
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作者 刘登忠 魏显贵 +1 位作者 杜思清 徐新煌 《矿物岩石》 CAS CSCD 北大核心 1997年第S1期4-11,共8页
通过米仓山西段1∶5万区域地质调查研究,从元古界火地垭群中解体出后河岩群,属太古-早元古代。认为前震旦纪变质基底以穹盆构造、叠加褶皱、多期面理置换、韧性剪切带为特色,确立了光雾山推覆构造,提出盖层变形以层滑褶皱为主。... 通过米仓山西段1∶5万区域地质调查研究,从元古界火地垭群中解体出后河岩群,属太古-早元古代。认为前震旦纪变质基底以穹盆构造、叠加褶皱、多期面理置换、韧性剪切带为特色,确立了光雾山推覆构造,提出盖层变形以层滑褶皱为主。对岩浆杂岩成功地进行了解体,认为侵入岩具多种成因类型并具多旋回演化特点,指出地台边缘的层序地层有别于陆棚边缘经典模式。 展开更多
关键词 米仓山 变质基底 后河岩群 构造样式 岩浆杂岩 层序地~层
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新矿物丁道衡矿的晶体结构 被引量:5
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作者 李国武 杨光明 +4 位作者 马喆生 施倪承 熊明 沈敢富 范海福 《矿物学报》 CAS CSCD 北大核心 2005年第4期313-320,共8页
对产于内蒙白云鄂博晶态富Ti和Fe2+的硅钛铈矿族新矿物丁道衡矿Ce4Fe2+(Ti,Fe2+)2Ti2Si4O22进行了晶体结构的精测,求得晶胞参数:a=1.34656(15)nm,b=0.57356(6)nm,c=1.10977(12)nm,β=100.636(2)°,晶胞体积V=0.84239(16)nm3。单位... 对产于内蒙白云鄂博晶态富Ti和Fe2+的硅钛铈矿族新矿物丁道衡矿Ce4Fe2+(Ti,Fe2+)2Ti2Si4O22进行了晶体结构的精测,求得晶胞参数:a=1.34656(15)nm,b=0.57356(6)nm,c=1.10977(12)nm,β=100.636(2)°,晶胞体积V=0.84239(16)nm3。单位晶胞中的分子数Z=2。晶体结构测定中分别用P21/a和C2/m空间群来进行晶体结构解析,解析表明,两种结构模型最终得到的R因子分别为0.026和0.021。两种结构精修后的原子坐标、键长键角都完全合理。根据结构分析及衍射数据消光规律统计认为,丁道衡矿的空间群应该为P21/a,而C2/m为赝对称空间群,结构属于具有C2/m赝对称的P21/a超结构,是一种超结构的新类型。 展开更多
关键词 新矿物 丁道衡矿 空间群 晶体结构 超结构
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