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The 4-canonical Maps of 3-folds of General Type
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作者 董佳琦 《Northeastern Mathematical Journal》 CSCD 2006年第1期119-126,共8页
The aim of this paper is to show that the 4-canonical maps of 3-folds of general type is birational when pg≥7 under some given conditions.
关键词 4-canonical map 3-fold general type birational equivalence
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Some birationality criteria on 3-folds with p_g>1 Dedicated to the memory of Professor XIAO Gang 被引量:2
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作者 CHEN Meng 《Science China Mathematics》 SCIE 2014年第11期2215-2234,共20页
We give some birationality criteria for m(m = 4,5,6,7) on general type 3-folds with pg 2 by means of an intensive classification. In particular,we show that 7 is not birational if and only if pg(X) = 2and X admits a g... We give some birationality criteria for m(m = 4,5,6,7) on general type 3-folds with pg 2 by means of an intensive classification. In particular,we show that 7 is not birational if and only if pg(X) = 2and X admits a genus 2 curve family of canonical degree23. When the canonical volume is large,we also characterize the birationality of 4,5 and 6. 展开更多
关键词 birationality criteria 3-folds of general type intensive classification
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On anti-pluricanonical systems of Q-Fano 3-folds
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作者 CHEN Meng 《Science China Mathematics》 SCIE 2011年第8期1547-1560,共14页
We investigate birationality of the anti-pluricanonical map Φ-m,the rational map defined by the anti-pluricanonical system |-mKX|,on weak Q-Fano 3-folds.
关键词 Q-Fano 3-folds anti-pluricanonical systems anti-volume birationality
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Some lower bounds for the canonical volume of 3-folds of general type
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作者 WANG MingZhi 《Science China Mathematics》 SCIE 2014年第12期2529-2538,共10页
Let V be a smooth projective 3-fold of general type. We show that the canonical volume K3 of V has a lower bound 1/10 provided q(V) 〉 0 and Ka ≥ 3 provided P4(V) ≥ 5. We also give some clean and better form for... Let V be a smooth projective 3-fold of general type. We show that the canonical volume K3 of V has a lower bound 1/10 provided q(V) 〉 0 and Ka ≥ 3 provided P4(V) ≥ 5. We also give some clean and better form for Noether inequalities for minimal 3-folds of general type. 展开更多
关键词 canonical volume Noether inequality 3-folds of general type
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6-CANONICAL MAPS OFNONSINGULAR MINIMAL 3-FOLDS
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作者 CHEN MENG 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 1995年第2期163-170,共8页
The aim of this paper is to study 6-canonical system of a nonsingular minimal 3-fold X. If|2Kx|is not composed of pencils, it is shown that is birational with possible exceptionsfor:
关键词 Canonical map Nonsingular minimal 3-fold Birational map.1991 MR Subject Classification 14E05 14J30.
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3-fold Morse序列的因子复杂度以及与其相似的一个排列(英文)
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作者 刘秋霞 牛敏 《应用数学》 CSCD 北大核心 2014年第4期899-905,共7页
我们证明3-fold Morse序列的一些性质,并且给出它的子词复杂度公式.此外,通过迭代一个映射产生一个实数序列,我们研究它的一些性质.最终证明这个实数序列与3-fold Morse产生相同的无穷排列.
关键词 3-fold Morse序列 无穷排列 因子复杂度
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Helical Coordination Polymer with a 3-Fold Interpenetration Structure Based on 5-(Hydroxymethyl)isophthalic Acid 被引量:9
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作者 徐中轩 马钰璐 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2017年第7期1193-1198,共6页
5-(Hydroxymethyl) isophthalic acid (H2HIA) as a novel organic ligand was prepared from 3,5-bis(methoxycarbonyl)benzoic acid by a two-step method. And then, a 3D helical coor- dination polymer with a 3-fold inter... 5-(Hydroxymethyl) isophthalic acid (H2HIA) as a novel organic ligand was prepared from 3,5-bis(methoxycarbonyl)benzoic acid by a two-step method. And then, a 3D helical coor- dination polymer with a 3-fold interpenetration structure, namely [Zn1/2(HIA)1/2(DPEE)1/2]n (1), was hydrothermally synthesized at 160 ℃, using H2HIA ligands to assemble with DPEE ligands and Zn2+ ions. Complex 1 crystalizes in orthorhombic system, space group Pnna, with a = 8.2118(5), b = 17.1698(7), c =14.9922(7) ?, V = 2113.82(18) ?3, μ = 1.194 mm-1, Z = 4 and S = 0.967. Moreover, some physical characteristics of complex 1, such as powder X-ray diffraction (PXRD), thermogravimetry analyses (TGA) and photoluminescent properties, were also investigated. 展开更多
关键词 5-(hydroxymethyl) isophthalic acid helical coordination polymer 3-fold interpenetration structure
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A 3-fold Interpenetrated lvt Cd(Ⅱ) Network Constructed from 4-[(3-pyridyl)methylamino]benzoate Acid
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作者 王庆伟 陈琳 +2 位作者 齐晓飞 王亚男 刘博 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2014年第5期757-763,共7页
A new three-dimensional(3D) coordination polymer, [Cd(L)2H2O]n·5nH2O 1 with 4-[(3-pyridyl)methylamino]benzoate acid(HL), has been synthesized by slow evaporation solvent at room temperature, and structura... A new three-dimensional(3D) coordination polymer, [Cd(L)2H2O]n·5nH2O 1 with 4-[(3-pyridyl)methylamino]benzoate acid(HL), has been synthesized by slow evaporation solvent at room temperature, and structurally characterized by elemental analysis, IR spectrum, thermal analysis, fluorescence spectrum and single-crystal X-ray diffraction. Compound 1 crystallizes in the tetragonal system, space group I-4, with a = 20.7937(16), c = 13.515(2), V = 5843.5(11) 3, C26H34CdN4O10, Mr = 674.97, Dc = 1.534 g/cm3, μ(MoKα) = 0.808 mm-1, F(000) = 2768, Z = 8, the final R = 0.0276 and wR = 0.0691 for 5323 observed reflections(I 〉 2σ(I)). The result of thermal analysis shows that 1 is stable under 290 ℃. Moreover, it exhibits blue photoluminescence at room temperature. 展开更多
关键词 4-[(3-pyridyl)methylamino]benzoate acid lvt topology 3-fold interpenetrated luminescent property
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The Production of CNT Flower-Like Structures with 3-Fold and 4-Fold Symmetries on a Pt/Si Substrate
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作者 Madjid Arab Marjorie David +1 位作者 Jean-Christophe Valmalette Christophe Ramseyer 《Advances in Chemical Engineering and Science》 2013年第1期78-81,共4页
Carbon nanotubes flower (CNTs-F) films were prepared by catalytic chemical vapor deposition (CVD) on a platinum (Pt) thin layer, supported on a silicon wafer. The products were synthesized from an aerosol composed of ... Carbon nanotubes flower (CNTs-F) films were prepared by catalytic chemical vapor deposition (CVD) on a platinum (Pt) thin layer, supported on a silicon wafer. The products were synthesized from an aerosol composed of ferrocene and toluene, as catalyst and carbon precursor respectively, at 820. The high synthesis temperature induces a modification of a Pt thin layer to a nano-structured island giving rise to the formation of CNTs-F during the following films growth step by CVD process. The suggested mechanism involves the selective diffusion of the catalyst and carbon atoms through the Pt grain boundaries. This results in the appearance of flower-like structures with 3-and 4-fold symmetries. 展开更多
关键词 Carbon Nanotube Aerosol-CVD 3-fold and 4-fold Symmetries Flower Shape
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Compact Solvmanifolds with a Closed G<sub>2</sub>-Structure
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作者 Marisa Fernández Jonatan Sanchez Jose A. Santisteban 《Advances in Pure Mathematics》 2018年第11期813-829,共17页
We consider a parametrized family of compact G2-calibrated solvmanifolds, and construct associative (so volume-minimizing submanifolds) 3-tori with respect to the closed G2-structure. We also study the Laplacian flow ... We consider a parametrized family of compact G2-calibrated solvmanifolds, and construct associative (so volume-minimizing submanifolds) 3-tori with respect to the closed G2-structure. We also study the Laplacian flow of this closed G2 form on the solvable Lie group underlying to each of these solvmanifolds, and show long time existence of the solution. 展开更多
关键词 G2-Structure Laplacian Flow ASSOCIATIVE 3-folds
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Two Interpenetrated and Polycatenated Zn(Ⅱ)Coordination Polymers:Syntheses,Structures and Luminescent Properties 被引量:1
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作者 吕丛 陈琳 +1 位作者 刘博 周实 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2018年第11期1786-1794,共9页
Two fascinating Zn(II)entangled coordination polymers,[Zn(eoba)(bbi)];·nH;O(1)and[Zn(boba)(bbi);];(2),(bbi=1,1?-(1,4-butanediyl)-bis(imidazole),H;eoba=4,4?-(ethane-1,2-diyldioxy)-dibenzoic acid,H;... Two fascinating Zn(II)entangled coordination polymers,[Zn(eoba)(bbi)];·nH;O(1)and[Zn(boba)(bbi);];(2),(bbi=1,1?-(1,4-butanediyl)-bis(imidazole),H;eoba=4,4?-(ethane-1,2-diyldioxy)-dibenzoic acid,H;boba=4,4?-(butane-1,4-diyldioxy)-dibenzoic acid),were obtained by hydrothermal technology and characterized by elemental analysis,infrared spectrum,thermogravimetric analysis and single-crystal X-ray diffraction.1 is a rare 2D→3D example with a 3-fold parallel interpenetration and polycatenaned architecture.2 features a scarce2D→2D example with a 3-fold parallel interpenetrating network which possesses polyrotaxane and polycatenane characters.Moreover,the luminescent properties of 1 and 2 have been discussed. 展开更多
关键词 3-fold interpenetration luminescent property crystal structure
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Syntheses, Crystal Structures, and Fluorescence Properties of Two 2D→2D Coordination Polymers Based on the Flexible 4-Substituted Bis(1,2,4-triazole) Ligand
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作者 PENG Yanfen LIU Tianbao WU Qiuyan 《Wuhan University Journal of Natural Sciences》 CAS CSCD 2019年第1期8-14,共7页
Two new 2 D → 2 D zinc(II) coordination polymers, [Zn(btre)0.5(nbdc)(H2 O)]n(1) and {[Zn(btre)0.5(Me Oip)(H2 O)2]·H2 O}n(2)(btre = 1,2-bis(1,2,4-triazol-4-yl)ethane, nbdc=3-nitro-1, 2-benzenedicarboxylate, Me Oi... Two new 2 D → 2 D zinc(II) coordination polymers, [Zn(btre)0.5(nbdc)(H2 O)]n(1) and {[Zn(btre)0.5(Me Oip)(H2 O)2]·H2 O}n(2)(btre = 1,2-bis(1,2,4-triazol-4-yl)ethane, nbdc=3-nitro-1, 2-benzenedicarboxylate, Me Oip=4-methoxybenzene-1, 3-dicarboxylate) were synthesized at room temperature condition and characterized by IR spectra, elemental analyses, single-crystal and powder X-ray diffractions. Three sets of equivalent 2 D(6, 3) networks parallel polycatenated with each other to give a 2 D → 2 D network in 1 and 2. There are strong π-π interactions and hydrogen bonding interactions between adjacent parallel polycatenated 2 D(6, 3) network in 1. Only hydrogen bonding interactions exist in 2. Thermal stabilities and luminescence of 1 and 2 were investigated. 展开更多
关键词 3-fold INTERPENETRATION 1 2-bis(1 2 4-triazol-4-yl)ethane 2D(6 3)network luminescence
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