期刊文献+
共找到42,745篇文章
< 1 2 250 >
每页显示 20 50 100
[(n-C_4H_9)_3SnO_2C(CH_2)_2CO_2Sn(C_4H_9-n)_3]: A Novel Three-dimensional Framework Structure of Organotin Complex 被引量:2
1
作者 尹汉东 王传华 +2 位作者 马春林 王勇 房海霞 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2003年第4期387-390,共4页
The bis(tributyltin) ester of succinic acid was synthesized by the reaction of disodium salt of succinic acid with tributyltin chloride in a molar ratio of 1:2. The crystal structure was determined by X-ray single-cry... The bis(tributyltin) ester of succinic acid was synthesized by the reaction of disodium salt of succinic acid with tributyltin chloride in a molar ratio of 1:2. The crystal structure was determined by X-ray single-crystal diffraction. It belongs to orthorhombic with space group Pccn, a = 20.949(3), b = 17.470(3), c = 20.345(3) Angstrom, V = 7446(2) Angstrom(3), Z = 8, D-c = 1.242 g/cm(3), mu = 1.365 mm(-1), F(000) = 2864, R = 0.0544 and wR = 0.1417. The tin atom is of five-coordination in a trigonal bipyramidal structure by bridging two carboxylate groups in different directions and the resulting structure which contains straight twist large ring channels along the axes of a, b and c is a three-dimensional framework polymer containing two different tin atoms. 展开更多
关键词 TRIBUTYLTIN glutaric acid crystal structure three-dimensional framework structure
在线阅读 下载PDF
Exploring the Three-dimensional Framework of Knowledge Service in the field of Library and Information Science(LIS)
2
作者 WANG Yuefen ZHANG Beibei WU Tingting 《Chinese Journal of Library and Information Science》 2010年第2期31-47,共17页
The evolution of the society and economy has stimulated the development of Knowledge Service(KS), making it an indispensable solution to address future challenges facing libraries and information institutions. However... The evolution of the society and economy has stimulated the development of Knowledge Service(KS), making it an indispensable solution to address future challenges facing libraries and information institutions. However at present, academic research on knowledge service is falling short and its definition is far from clear and complete. As such,this article proposes the Three-dimensional Framework Knowledge Service(TdFKS) for libraries and information institutions based on the knowledge value chain model. By making reliability analysis and mean value analysis of a questionnaire survey result, the article clarifies the structure of the three-dimensional framework and verifies the rationality of the TdFKS. 展开更多
关键词 Libraries and information institutions Knowledge service three-dimensional framework Reliability analysis Mean value analysis
原文传递
Analysis on Discourse Construction of HK Riots between HK Protesters and China's Mainland Media Based on Fairclough’s Three-dimensional Framework of Critical Discourse Analysis
3
作者 Jie Li 《教育研究前沿(中英文版)》 2020年第3期159-166,共8页
The Critical Discourse Analysis(CDA)is an interdisciplinary tool in various conditions,which aims to provide a better understanding of sociocultural aspects of texts and accounts of the production of internal structur... The Critical Discourse Analysis(CDA)is an interdisciplinary tool in various conditions,which aims to provide a better understanding of sociocultural aspects of texts and accounts of the production of internal structure,and overall organization of texts as well as to provide a critical dimension in its theoretical and descriptive accounts of texts.Since June last year,HK protests or HK violence have been frequently reported by worldwide media.In this paper,the author aims to find out how the HK protesters and the Mainland media describe the same event based on the three-dimensional framework of CDA.At last,the author concludes that the mainland media generally describe the event as violence and riot while the HK protesters define themselves as warriors striving for more freedom,justice and democracy.Besides,on this event,the Mainland media mainly accuses some western countries of interference into HK affairs,which is undoubtedly of China’s internal affairs,and the media give full support to the HK police in safeguarding the peace and stability of Hong Kong.But from the perspective of HK protesters,they firmly believe that they are using their actions to protect all the people of HK,and they are defending their values such as freedom,democracy and justice.These are two totally different systems of language,and the author also gives its potential reasons in the paper so as to offer some viewpoints in this aspect in combination with the CDA theory. 展开更多
关键词 The Critical Discourse Analysis The three-dimensional framework The HK Protest The Discourse Construction The HK Riot
在线阅读 下载PDF
A Dicyanamido-bridged Zinc(Ⅱ) Complex Based on the Bis(4-pyridyl)ethane with a Three-dimensional Framework 被引量:3
4
作者 冯勋 王利亚 +2 位作者 师新阁 赵建社 孙倩 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2010年第10期1567-1573,共7页
A novel dicyanamido-bridged 3D polymeric complex {[Zn2(bpa)2(dca)]dca}n (1) (dca = dicyanamide anion,bpa = 1,2-bis(4-pyridyl)ethane) has been synthesized by reacting 1,2-bis(4-pyridyl)ethane with zinc salt... A novel dicyanamido-bridged 3D polymeric complex {[Zn2(bpa)2(dca)]dca}n (1) (dca = dicyanamide anion,bpa = 1,2-bis(4-pyridyl)ethane) has been synthesized by reacting 1,2-bis(4-pyridyl)ethane with zinc salt in the presence of sodium dicyanamide,and characterized by elemental analysis,IR spectra and X-ray diffraction. It crystallizes in the monoclinic system,space group C2/c with a = 18.587(3),b = 20.070(3),c = 8.7957(13) ,β = 100.611(2)o,V = 3225.0(8) 3,Mr = 539.92,μ = 0.789 mm-1,F(000) = 1116,Z = 4,ρ = 1.112 (g/cm3),R = 0.0582 and wR = 0.1762. Complex 1 forms a 3D porous framework through the bpa and dca ligands,and gives 1-D coordination channels encapsulated by the vip dca molecules. Complex 1 also displays strong photo-luminescent properties in the solid state at room temperature. 展开更多
关键词 metal-organic frameworks dieyanamido-bridge interpenetrating luminescence
在线阅读 下载PDF
Unique electromagnetic wave absorber for three-dimensional framework engineering with copious heterostructures 被引量:8
5
作者 Liyuan Yu Qianqian Zhu +3 位作者 Zhiqiang Guo Yuhang Cheng Zirui Jia Guanglei Wu 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2024年第3期129-139,共11页
In order to obtain high-performance electromagnetic wave absorbers,the adjustment of structure and components is essential.Based on the above requirements,this system forms a three-dimensional frame structure consisti... In order to obtain high-performance electromagnetic wave absorbers,the adjustment of structure and components is essential.Based on the above requirements,this system forms a three-dimensional frame structure consisting of MXene and transition metal oxides(TMOs)through efficient electrostatic self-assembly.This three-dimensional network structure has rich heterojunction structures,which can cause a large amount of interface polarization and conduction losses in incident electromagnetic waves.Hollow structures cause multiple reflections and scattering of electromagnetic waves,which is also an important reason for further increasing electromagnetic wave losses.When the doping ratio is 1:1,the system has the best impedance matching,the maximum effective absorption bandwidth(EAB max)can reach 5.12 GHz at 1.7 mm,and the minimum reflection loss(RL_(min))is-50.30 dB at 1.8 mm.This provides a reference for the subsequent formation of 2D-MXene materials into 3D materials. 展开更多
关键词 MXene three-dimensional frame Heterojunction structure Conduction loss Electromagnetic wave absorption
原文传递
Synthesis, Crystal Structure and Gas Adsorption of a Two-fold Interpenetrated Three-dimensional Framework {[Cd(2-NO_2-BDC)(4,4?-DPA)]·(DMF)}_n 被引量:1
6
作者 刘瑛 王玉玲 +2 位作者 陈岭 刘庆燕 姚阳 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2016年第6期921-928,共8页
The reaction of Cd(NO_3)_2·4H_2O with 4,4?-dipyridylacetylene(4,4?-DPA) and 2-nitroterephthalic acid(2-NO_2-H_2BDC) in DMF/H_2O mixed solvent has afforded a compound {[Cd(2-NO_2-BDC)(4,4?-DPA)]·... The reaction of Cd(NO_3)_2·4H_2O with 4,4?-dipyridylacetylene(4,4?-DPA) and 2-nitroterephthalic acid(2-NO_2-H_2BDC) in DMF/H_2O mixed solvent has afforded a compound {[Cd(2-NO_2-BDC)(4,4?-DPA)]·(DMF)}_n(1). Compound 1 has been characterized by single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetry analysis, and IR spectrum. Compound 1 crystallizes in the monoclinic system, space group P21/n, with a = 12.1488(3), b = 14.6689(3), c = 13.1615(3) ?, β = 111.809(3)o, V = 2177.63(9) ?~3, Z = 4, C_(23)H_(18)N_4O_7 Cd, M_r = 574.81, D_c = 1.753 g/cm^3, μ = 8.523 mm^(-1), F(000) = 1152, the final R = 0.0411 and wR = 0.1064 for 3589 observed reflections with I 〉 2s(I). In compound 1, the Cd(Ⅱ) ions are linked by the carboxylate groups of 2-NO_2-BDC ligands to give a two-dimensional layered structure based on the centrosymmetric dinuclear Cd_2(COO)_2 units, which are further connected by the 4,4?-DPA ligands to produce a three-dimensional framework with pcu topology. Careful examination revealed that compound 1 is a 2-fold interpenetrating framework. Furthermore, the gas adsorption properties of 1 for N_2 and CO_2 have also been investigated. 展开更多
关键词 synthesis 2-fold interpenetrating framework crystal structure gas adsorption
在线阅读 下载PDF
Synthesis and Structural Characterization of One New Polyoxotungstate Connected via Potassium Cations with aThree-dimensional Framework: H_6Na_2K_4(H_2W_(12)O_(42))Cl_2·14H_2O
7
作者 刘颖 窦建民 +4 位作者 王大齐 张宪玺 李大成 周雷 徐峰 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2007年第6期721-726,共6页
One new polyoxotungstate complex H6Na2K4(H2W12O42)Cl2·14H2O 1 has been prepared in the beaker solution and characterized by elemental analysis and IR spectroscopy. Crystal data: H36Cl2K4W12Na2O56, Mr = 3411.77... One new polyoxotungstate complex H6Na2K4(H2W12O42)Cl2·14H2O 1 has been prepared in the beaker solution and characterized by elemental analysis and IR spectroscopy. Crystal data: H36Cl2K4W12Na2O56, Mr = 3411.77, monoclinic, space group P21/c, a = 11.5734(16), b = 14.3136(19), c = 15.459(2)A, β = 105.601(2)°, V = 2466.5(6)A^3, Z = 2, Dc = 4.594 g/cm^3, F(000) = 3008, μ = 28.447 mm^-1, R = 0.0574 and wR = 0.1239 (Ⅰ〉 2σ(Ⅰ)). Single-crystal X-ray diffraction analysis results reveal that a three-dimensional architecture in the title compound is constructed from the H2W12O42^10- units linked by potassium. 展开更多
关键词 POLYOXOTUNGSTATE POTASSIUM X-ray analysis three-dimensional architecture
在线阅读 下载PDF
Antimony nanoparticles encapsulated in three-dimensional porous carbon frameworks for high-performance rechargeable batteries
8
作者 An-Qi Chen Si-Guang Guo +5 位作者 Yu Liu Ling Long Zhuo Li Biao Gao Paul K.Chu Kai-Fu Huo 《Rare Metals》 2025年第5期3026-3036,共11页
Antimony(Sb)is regarded as a potential candidate for next-generation anode materials for rechargeable batteries because it has a high theoretical specific capacity,excellent conductivity and appropriate reaction poten... Antimony(Sb)is regarded as a potential candidate for next-generation anode materials for rechargeable batteries because it has a high theoretical specific capacity,excellent conductivity and appropriate reaction potential.However,Sb-based anodes suffer from severe volume expansion of>135%during the lithiation-delithiation process.Hence,we construct a novel Sb@C composite encapsulating the Sb nanoparticles into highly conductive three-dimensional porous carbon frameworks via the one-step magnesiothermic reduction(MR).The porous carbon provides buffer spaces to accommodate the volume expansion of Sb.Meanwhile,the three-dimensional(3D)interconnected carbon frameworks shorten the ion/electron transport pathway and inhibit the overgrowth of unstable solid-electrolyte interfaces(SEIs).Consequently,the 3D Sb@C composite displays remarkable electrochemical performance,including a high average Coulombic efficiency(CE)of>99%,high initial capability of 989 mAh·g^(-1),excellent cycling stability for over 1000 cycles at a high current density of 5 A·g^(-1).Furthermore,employing a similar approach,this 3D Sb@C design paradigm holds promise for broader applications across fast-charging and ultralong-life battery systems beyond Li+.This work aims to advance practical applications for Sb-based anodes in next-generation batteries. 展开更多
关键词 Rechargeable battery Antimony anode Porous carbon framework Magnesiothermic reduction Cycle life
原文传递
Three-dimensional covalent organic framework photocatalyst with asymmetrically coordinated single-atom cobalt for highly efficient CO_(2)reduction reactions
9
作者 Wuqing Luo Jia Chen +8 位作者 Zhuozhuo Tang Baopeng Yang Guoxin Chen Shengyao Wang Gen Chen Min Liu Hong Xu Jinhua Ye Ning Zhang 《Journal of Energy Chemistry》 2025年第9期400-409,I0011,共11页
Three-dimensional(3D)covalent organic frameworks(COFs)have attracted extensive attention as photocatalysts for CO_(2)reduction reactions.Introducing metal atoms is essential for enhancing activity,but previous metal s... Three-dimensional(3D)covalent organic frameworks(COFs)have attracted extensive attention as photocatalysts for CO_(2)reduction reactions.Introducing metal atoms is essential for enhancing activity,but previous metal sites in 3D COFs predominantly exhibit symmetrical coordination,making them unsuitable for CO_(2)activation.Here,we design a 3D COF with 2,2'-pyridine linked around tetra-(4-anilyl)methane(TCM-Bpy-COF),where Co^(2+)is asymmetrically coordinated by bipyridine and acetates(TCMBpy-COF-CoAc).The TCM-Bpy-COF-CoAc exhibits outstanding photocatalytic CO_(2)reduction performance under weak visible light,achieving a CO evolution rate of 26,650μmol g^(-1)h^(-1)under 5 W of lightemitting-diode(LED)lamp and high apparent quantum efficiency.The performance far exceeds that of symmetrically coordinated bipyridine-Co-bipyridine TCM-Bpy-COF and surpasses most reported COF-based photocatalysts.In-situ spectral characterizations and theoretical calculations show that asymmetric N,O-coordination around the Co^(2+)center polarizes electron density and lowers reaction energy barriers of^(*)COOH intermediates,enhancing the conversion of CO_(2)to CO.This work inspires the design of 3D COF-based photocatalysts with highly catalytic efficiency. 展开更多
关键词 Covalent organic frameworks Photocatalysis CO_(2)reduction reaction Singe atom catalyst
在线阅读 下载PDF
Ligand-directed construction of cobalt-oxo cluster-based organic frameworks:Structural modulation,semiconductor,and antiferromagnetic properties
10
作者 SHI Jinlian LIU Xiaoru XU Zhongxuan 《无机化学学报》 北大核心 2026年第1期45-54,共10页
Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully construct... Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully constructed by coordinatively assembling the semi-rigid multidentate ligand 5-(1-carboxyethoxy)isophthalic acid(H₃CIA)with the Nheterocyclic ligands 1,4-di(4H-1,2,4-triazol-4-yl)benzene(1,4-dtb)and 1,4-di(1H-imidazol-1-yl)benzene(1,4-dib),respectively,around Co^(2+)ions.Single-crystal X-ray diffraction analysis revealed that in both complexes HU23 and HU24,the CIA^(3-)anions adopt aκ^(7)-coordination mode,bridging six Co^(2+)ions via their five carboxylate oxygen atoms and one ether oxygen atom.This linkage forms tetranuclear[Co4(μ3-OH)2]^(6+)units.These Co-oxo cluster units were interconnected by CIA^(3-)anions to assemble into 2D kgd-type structures featuring a 3,6-connected topology.The 2D layers were further connected by 1,4-dtb and 1,4-dib,resulting in 3D pillar-layered frameworks for HU23 and HU24.Notably,despite the similar configurations of 1,4-dtb and 1,4-dib,differences in their coordination spatial orientations lead to topological divergence in the 3D frameworks of HU23 and HU24.Topological analysis indicates that the frameworks of HU23 and HU24 can be simplified into a 3,10-connected net(point symbol:(4^(10).6^(3).8^(2))(4^(3))_(2))and a 3,8-connected tfz-d net(point symbol:(4^(3))_(2)((4^(6).6^(18).8^(4)))),respectively.This structural differentiation confirms the precise regulatory role of ligands on the topology of metal-organic frameworks.Moreover,the ultraviolet-visible absorption spectra confirmed that HU23 and HU24 have strong absorption capabilities for ultraviolet and visible light.According to the Kubelka-Munk method,their bandwidths were 2.15 and 2.08 eV,respectively,which are consistent with those of typical semiconductor materials.Variable-temperature magnetic susceptibility measurements(2-300 K)revealed significant antiferromagnetic coupling in both complexes,with their effective magnetic moments decreasing markedly as the temperature lowered.CCDC:2457554,HU23;2457553,HU24. 展开更多
关键词 semi-rigid carboxylic acid ligands three-dimensional framework tetranuclear cobalt-oxo cluster semiconductor material antiferromagnetic magnetism
在线阅读 下载PDF
A New Heteropolyoxotungstate with a Three-dimensional All-inorganic Framework [(C_2H_4N_2)_4(P_4Co_3W_4O_(28)H_6)(H_2C_2O_4)]_n
11
作者 孙军 孙宇 +1 位作者 陈亚光 孟凡霞 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2010年第6期962-966,共5页
A new heteropolyoxotungstate [(C2H4N2)4(P4Co3W4O28H6)(H2C2O4)]n with a three-dimensional framework was hydrothermally synthesized.The compound crystallizes in a tetragonal system,space group I41/a with a = 17.1... A new heteropolyoxotungstate [(C2H4N2)4(P4Co3W4O28H6)(H2C2O4)]n with a three-dimensional framework was hydrothermally synthesized.The compound crystallizes in a tetragonal system,space group I41/a with a = 17.1006(17),b = 17.1006(7),c = 10.7525(5),V = 3144.2(2)3,Z = 4,Dc = 3.795 g·cm-3,F(000) = 3300,MoKα(λ = 0.71073 ),μ = 16.460 mm-1,the final R = 0.0335 and wR = 0.0776.In the heteropolyoxotungstate,tungsten-oxygen octahedra are linked by sharing two cis-vertexes into an infinite helical chain extending along the c axis.Cobalt atoms in the octahedral geometry act as the linkers of these chains,forming a three-dimensional framework.The cobalt and phosphorus atoms in the tetrahedral geometry play a role in stabilizing the three-dimensional framework.Ethylenediamine molecules are polymerized into organic chains which locate in the interspaces of the framework in the way of interwinding with the W-O chains. 展开更多
关键词 hydrothermal synthesis POLYOXOTUNGSTATE three-dimensional framework W-O chains organic ammine
在线阅读 下载PDF
Three-dimensional Covalent Organic Frameworks as Host Materials for Lithium-Sulfur Batteries 被引量:3
12
作者 Zhen Li Hang-Yu Zhou +4 位作者 Fu-Lai Zhao Tian-Xiong Wang Xuesong Ding Bao-Hang Han Wei Feng 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2020年第5期550-557,I0008,共9页
Two reported three-dimensional covalent organic frameworks(3D-COFs),COF-300 and COF-301,which have hierarchical porous structures and large pore volumes,were synthesized and employed as host materials for lithium-sulf... Two reported three-dimensional covalent organic frameworks(3D-COFs),COF-300 and COF-301,which have hierarchical porous structures and large pore volumes,were synthesized and employed as host materials for lithium-sulfur batteries.Owing to possessing excellent porosities as well as abundant hydroxyl groups in the pore walls,COF-301 can not only trap lithium polysulfides(PSs)via physical adsorption inside the pores,but also capture PSs by chemical interactions to relieve the shuttle effect.Interestingly,it is the first time that 3D-COFs were utilized as host materials for lithium-sulfur batteries as well as hydroxyl groups were introduced into COFs for improving the battery performance.As a result,COF-301@S as cathode material could reserve the capacity of 411.6 mA·h·g^-1 after 500 cycles with only 0.081%fading per cycle at 0.5 C,exhibiting better battery performance compared with COF-300@S.This study not only expands the applications of 3D-COFs but also provides a new route for designing lithium-sulfur batteries. 展开更多
关键词 three-dimensional covalent organic framework Flost material Lithium-sulfur battery Flydroxyl group Chemical interaction
原文传递
Three-dimensional paper-like graphene framework with highly orientated laminar structure as binder-free supercapacitor electrode 被引量:5
13
作者 Yidan Gao Yaoyao Zhang +7 位作者 Yong Zhang Lijing Xie Xiaoming Li Fangyuan Su Xianxian Wei Zhiwei Xu Chengmeng Chen Rong Cai 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2016年第1期49-54,共6页
A free-standing paper-like three-dimensional graphene framework(3DGF) with orientated laminar structure and interconnected macropores, was obtained by the hard template-directed ordered assembly. As the sacrificial ... A free-standing paper-like three-dimensional graphene framework(3DGF) with orientated laminar structure and interconnected macropores, was obtained by the hard template-directed ordered assembly. As the sacrificial templates, polystyrene(PS) latex spheres were assembled with graphene oxide(GO) to build up a sandwich type composite film, followed by heat removal of which with a simultaneous reduction of GO. The 3DGF exhibited high specific surface area of 402.5 m2/g, controllable pores and mechanical flexibility, which was employed as the binder-free supercapacitor electrode and shows high specific gravimetric capacitance of 95 F/g at 0.5 A/g, with enhanced rate capability in 3 electrode KOH system. 展开更多
关键词 3D graphene framework Polystyrene Sacrificial template Supercapacitor
在线阅读 下载PDF
Global Mapping of Three-Dimensional Urban Structures Reveals Escalating Utilization in the Vertical Dimension and Pronounced Building Space Inequality 被引量:1
14
作者 Xiaoping Liu Xinxin Wu +6 位作者 Xuecao Li Xiaocong Xu Weilin Liao Limin Jiao Zhenzhong Zeng Guangzhao Chen Xia Li 《Engineering》 2025年第4期86-99,共14页
Three-dimensional(3D)urban structures play a critical role in informing climate mitigation strategies aimed at the built environment and facilitating sustainable urban development.Regrettably,there exists a significan... Three-dimensional(3D)urban structures play a critical role in informing climate mitigation strategies aimed at the built environment and facilitating sustainable urban development.Regrettably,there exists a significant gap in detailed and consistent data on 3D building space structures with global coverage due to the challenges inherent in the data collection and model calibration processes.In this study,we constructed a global urban structure(GUS-3D)dataset,including building volume,height,and footprint information,at a 500 m spatial resolution using extensive satellite observation products and numerous reference building samples.Our analysis indicated that the total volume of buildings worldwide in2015 exceeded 1×10^(12)m^(3).Over the 1985 to 2015 period,we observed a slight increase in the magnitude of 3D building volume growth(i.e.,it increased from 166.02 km3 during the 1985–2000 period to 175.08km3 during the 2000–2015 period),while the expansion magnitudes of the two-dimensional(2D)building footprint(22.51×10^(3) vs 13.29×10^(3)km^(2))and urban extent(157×10^(3) vs 133.8×10^(3)km^(2))notably decreased.This trend highlights the significant increase in intensive vertical utilization of urban land.Furthermore,we identified significant heterogeneity in building space provision and inequality across cities worldwide.This inequality is particularly pronounced in many populous Asian cities,which has been overlooked in previous studies on economic inequality.The GUS-3D dataset shows great potential to deepen our understanding of the urban environment and creates new horizons for numerous 3D urban studies. 展开更多
关键词 three-dimensional Global mapping Building volume Building height Building space inequality
在线阅读 下载PDF
A Three-dimensional Porous Metal-organic Framework Based on Cyano Unit and 1,4-Bis(1,2,4-triazol-1-yl)butane(btb):{[Cu_8(btb)_2(CN)_8].3H_2O}_n 被引量:3
15
作者 周馨慧 李洪辉 黄维 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2012年第1期33-38,共6页
The title coordination polymer 1,{[Cu8(btb)2(CN)8].3H2O}n(btb = 1,4-bis(1,2,4-triazol-1-yl)butane),has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction.Complex... The title coordination polymer 1,{[Cu8(btb)2(CN)8].3H2O}n(btb = 1,4-bis(1,2,4-triazol-1-yl)butane),has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction.Complex 1 crystallizes in monoclinic,space group C2/c with a = 1.2938(3),b = 1.9422(5),c = 0.9406(2) nm,β = 121.891(4)°,V = 2.0066(9) nm3,C24H30Cu8N20O3,Mr = 1155.00,Dc = 1.912 g/cm3,μ(MoKα) = 4.209 mm?1,F(000) = 1140,GOF = 1.184,Z = 2,the final R = 0.0634 and wR = 0.1503 for I 2σ(I).In complex 1,one-dimensional CuCN zigzag chains are linked by triazolyl groups of btb ligands to form two-dimensional networks,which are further bridged by 1,4-butyl moieties of btb ligands to fabricate a three-dimensional order framework,in which one-dimensional ellipsoid-like channels are observed. 展开更多
关键词 CYANO 1 4-bis(1 2 4-triazol-1-yl)butane metal-organic framework(MOF) complex Cu+
在线阅读 下载PDF
Three-dimensional line-of-sight-angle-constrained leader-following cooperative interception guidance law with prespecified impact time 被引量:2
16
作者 Hao YOU Xinlong CHANG Jiufen ZHAO 《Chinese Journal of Aeronautics》 2025年第1期491-506,共16页
To address the problem of multi-missile cooperative interception against maneuvering targets at a prespecified impact time and desired Line-of-Sight(LOS)angles in ThreeDimensional(3D)space,this paper proposes a 3D lea... To address the problem of multi-missile cooperative interception against maneuvering targets at a prespecified impact time and desired Line-of-Sight(LOS)angles in ThreeDimensional(3D)space,this paper proposes a 3D leader-following cooperative interception guidance law.First,in the LOS direction of the leader,an impact time-controlled guidance law is derived based on the fixed-time stability theory,which enables the leader to complete the interception task at a prespecified impact time.Next,in the LOS direction of the followers,by introducing a time consensus tracking error function,a fixed-time consensus tracking guidance law is investigated to guarantee the consensus tracking convergence of the time-to-go.Then,in the direction normal to the LOS,by combining the designed global integral sliding mode surface and the second-order Sliding Mode Control(SMC)theory,an innovative 3D LOS-angle-constrained interception guidance law is developed,which eliminates the reaching phase in the traditional sliding mode guidance laws and effectively saves energy consumption.Moreover,it effectively suppresses the chattering phenomenon while avoiding the singularity issue,and compensates for unknown interference caused by target maneuvering online,making it convenient for practical engineering applications.Finally,theoretical proof analysis and multiple sets of numerical simulation results verify the effectiveness,superiority,and robustness of the investigated guidance law. 展开更多
关键词 three-dimensional cooperative interception Leader-following missiles Prespecified impact time LOS-angle-constrained Fixed-time stability Global integral sliding mode
原文传递
Developing an Approach for a Three-Dimensional Hydrogeologic Framework to Find Water in Northern Ghana 被引量:2
17
作者 Shannon Holt Alexandra Lutz +3 位作者 Bansaga Saga David L. Berger James M. Thomas Braimah Apambire 《Open Journal of Modern Hydrology》 2015年第4期105-120,共16页
The purpose of this study was to develop an approach for constructing a three-dimensional hydrogeologic framework using borehole driller logs. The ultimate goal is to increase drilling success rates via a better under... The purpose of this study was to develop an approach for constructing a three-dimensional hydrogeologic framework using borehole driller logs. The ultimate goal is to increase drilling success rates via a better understanding of the regional hydrogeologic framework in northern Ghana. Groundwater development has increased in northern Ghana, but drilling successful boreholes is difficult due to complex geology and limited aquifer characteristic information. An approach was developed to construct a three-dimensional hydrogeologic framework of the basin using 900 borehole logs from World Vision International’s Ghana Integrated Water, Sanitation, and Hygiene Project, located in northern Ghana. The study’s approach consists of: evaluating potential software programs;collecting borehole drilling logs;data QA/QC;data standardization and normalization;analysis for trends and correlations;and creation of a three-dimensional hydrogeologic framework and two-dimensional cross sections. This approach can be used and adapted by others working to provide groundwater in developing countries. 展开更多
关键词 GROUNDWATER Management HYDROGEOLOGY GROUNDWATER RESOURCES Hydrogeologic framework Ghana
暂未订购
Three-dimensional carbon framework as high-proportion sulfur host for high-performance lithium-sulfur batteries 被引量:6
18
作者 Xianbin Liu Zechen Xiao +6 位作者 Changgan Lai Shuai Zou Ming Zhang Kaixi Liu Yanhong Yin Tongxiang Liang Ziping Wu 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2020年第13期84-91,共8页
Lithium-sulfur(Li-S)batteries are anticipated as one of the most promising candidates for the highenergy-density storage systems.However,the insulating nature and shuttling effect of sulfur severely limits their perfo... Lithium-sulfur(Li-S)batteries are anticipated as one of the most promising candidates for the highenergy-density storage systems.However,the insulating nature and shuttling effect of sulfur severely limits their performance.The incorporation of sulfur with carbon materials has been deemed as one of the most powerful strategies to improve electrical conductivity and suppress soluble polysulfide shuttling.Herein,a novel three-dimensional carbon framework(3DCF)is prepared and employed as a sulfur host(3DCF@S)for Li-S batteries.The 3DCF not only supplies abundant paths for lithium ion diffusion and electron transport,but also strengthens polysulfide immobilization during the lithium/sulfur conversion reactions.As a result,the 3DCF@S with high sulfur content of 90%exhibits a high capacity of 1366 mA h/g at 0.1 C and excellent cycling stability with a satisfactory capacity of 601 mA h/g after 600 cycles at 2.0 C.The resultant Li-S button battery based 3DCF@S electrode could power a light-emitting diode for 2 h.The acquired 3DCF@S is expected to be widely used in Li-S batteries and this study will promote developments of carbon/sulfur composites for Li-S batteries. 展开更多
关键词 3D carbon framework High sulfur proportion Lithium-sulfur battery High capacity Outstanding cycling stability
原文传递
Quasi-Three-Dimensional Cyclotriphosphazene-Based Covalent Organic Framework Nanosheet for Efficient Oxygen Reduction 被引量:2
19
作者 Jianhong Chang Cuiyan Li +8 位作者 Xiaoxia Wang Daohao Li Jie Zhang Xiaoming Yu Hui Li Xiangdong Yao Valentin Valtchev Shilun Qiu Qianrong Fang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第9期550-561,共12页
Metal-free carbon-based materials are considered as promising oxygen reduction reaction(ORR)electrocatalysts for clean energy conversion,and their highly dense and exposed carbon active sites are crucial for efficient... Metal-free carbon-based materials are considered as promising oxygen reduction reaction(ORR)electrocatalysts for clean energy conversion,and their highly dense and exposed carbon active sites are crucial for efficient ORR.In this work,two unique quasi-three-dimensional cyclotriphosphazene-based covalent organic frameworks(Q3CTP-COFs)and their nanosheets were successfully synthesized and applied as ORR electrocatalysts.The abundant electrophilic structure in Q3CTP-COFs induces a high density of carbon active sites,and the unique bilayer stacking of[6+3]imine-linked backbone facilitates the exposure of active carbon sites and accelerates mass diffusion during ORR.In particular,bulk Q3CTP-COFs can be easily exfoliated into thin COF nanosheets(NSs)due to the weak interlayerπ-πinteractions.Q3CTP-COF NSs exhibit highly efficient ORR catalytic activity(half-wave potential of 0.72 V vs.RHE in alkaline electrolyte),which is one of the best COF-based ORR electrocatalysts reported so far.Furthermore,Q3CTP-COF NSs can serve as a promising cathode for Zn-air batteries(delivered power density of 156 mW cm-2 at 300 mA cm^(-2)).This judicious design and accurate synthesis of such COFs with highly dense and exposed active sites and their nanosheets will promote the development of metal-free carbon-based electrocatalysts. 展开更多
关键词 Covalent organic framework Quasi-three-dimensional structures Oxygen reduction reaction Metal-free electrocatalyst
在线阅读 下载PDF
Three-dimensional models:from cell culture to Patient-Derived Organoid and its application to future liposarcoma research
20
作者 SAYUMI TAHARA SYDNEY RENTSCH +4 位作者 FERNANDA COSTAS CASAL DE FARIA PATRICIA SARCHET ROMA KARNA FEDERICA CALORE RAPHAEL E.POLLOCK 《Oncology Research》 SCIE 2025年第1期1-13,共13页
Liposarcoma is one of the most common soft tissue sarcomas,however,its occurrence rate is still rare compared to other cancers.Due to its rarity,in vitro experiments are an essential approach to elucidate liposarcoma ... Liposarcoma is one of the most common soft tissue sarcomas,however,its occurrence rate is still rare compared to other cancers.Due to its rarity,in vitro experiments are an essential approach to elucidate liposarcoma pathobiology.Conventional cell culture-based research(2D cell culture)is still playing a pivotal role,while several shortcomings have been recently under discussion.In vivo,mouse models are usually adopted for pre-clinical analyses with expectations to overcome the issues of 2D cell culture.However,they do not fully recapitulate human dedifferentiated liposarcoma(DDLPS)characteristics.Therefore,three-dimensional(3D)culture systems have been the recent research focus in the cell biology field with the expectation to overcome at the same time the disadvantages of 2D cell culture and in vivo animal models and fill in the gap between them.Given the liposarcoma rarity,we believe that 3D cell culture techniques,including 3D cell cultures/co-cultures,and Patient-Derived tumor Organoids(PDOs),represent a promising approach to facilitate liposarcoma investigation and elucidate its molecular mechanisms and effective therapy development.In this review,we first provide a general overview of 3D cell cultures compared to 2D cell cultures.We then focus on one of the recent 3D cell culture applications,Patient-Derived Organoids(PDOs),summarizing and discussing several PDO methodologies.Finally,we discuss the current and future applications of PDOs to sarcoma,particularly in the field of liposarcoma. 展开更多
关键词 Cell culture LIPOSARCOMA Patient-Derived Organoid(PDO) SPHEROID three-dimensional(3D)cell culture
暂未订购
上一页 1 2 250 下一页 到第
使用帮助 返回顶部