期刊文献+
共找到3,068篇文章
< 1 2 154 >
每页显示 20 50 100
Quantitatively characterizing sandy soil structure altered by MICP using multi-level thresholding segmentation algorithm 被引量:1
1
作者 Jianjun Zi Tao Liu +3 位作者 Wei Zhang Xiaohua Pan Hu Ji Honghu Zhu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第10期4285-4299,共15页
The influences of biological,chemical,and flow processes on soil structure through microbially induced carbonate precipitation(MICP)are not yet fully understood.In this study,we use a multi-level thresholding segmenta... The influences of biological,chemical,and flow processes on soil structure through microbially induced carbonate precipitation(MICP)are not yet fully understood.In this study,we use a multi-level thresholding segmentation algorithm,genetic algorithm(GA)enhanced Kapur entropy(KE)(GAE-KE),to accomplish quantitative characterization of sandy soil structure altered by MICP cementation.A sandy soil sample was treated using MICP method and scanned by the synchrotron radiation(SR)micro-CT with a resolution of 6.5 mm.After validation,tri-level thresholding segmentation using GAE-KE successfully separated the precipitated calcium carbonate crystals from sand particles and pores.The spatial distributions of porosity,pore structure parameters,and flow characteristics were calculated for quantitative characterization.The results offer pore-scale insights into the MICP treatment effect,and the quantitative understanding confirms the feasibility of the GAE-KE multi-level thresholding segmentation algorithm. 展开更多
关键词 Soil structure MICRO-CT multi-level thresholding MICP Genetic algorithm(GA)
下载PDF
Non-flammable long chain phosphate ester based electrolyte via competitive solventized structures for high-performance lithium metal batteries
2
作者 Li Liao Zhiqiang Han +16 位作者 Xuanjie Feng Pan Luo Jialin Song Yin Shen Xiaoshuang Luo Xinpeng Li Xuanzhong Wen Bo Yu Junchen Chen Bingshu Guo Mingshan Wang Yun Huang Hongmei Zhang Mengmeng Yin Jiangtao Liu Yuanhua Lin Xing Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第10期156-165,I0004,共11页
Safety remains a persistent challenge for high-energy-density lithium metal batteries(LMBs).The development of safe and non-flammable electrolytes is especially important in harsh conditions such as high temperatures.... Safety remains a persistent challenge for high-energy-density lithium metal batteries(LMBs).The development of safe and non-flammable electrolytes is especially important in harsh conditions such as high temperatures.Herein,a flame-retardant,low-cost and thermally stable long chain phosphate ester based(tributyl phosphate,TBP)electrolyte is reported,which can effectively enhance the cycling stability of highly loaded high-nickel LMBs with high safety through co-solvation strategy.The interfacial compatibility between TBP and electrode is effectively improved using a short-chain ether(glycol dimethyl ether,DME),and a specially competitive solvation structure is further constructed using lithium borate difluorooxalate(LiDFOB)to form the stable and inorganic-rich electrode interphases.Benefiting from the presence of the cathode electrolyte interphase(CEI)and solid electrolyte interphase(SEI)enriched with LiF and Li_(x)PO_(y)F_(z),the electrolyte demonstrates excellent cycling stability assembled using a 50μm lithium foil anode in combination with a high loading NMC811(15.4 mg cm^(-2))cathode,with 88%capacity retention after 120 cycles.Furthermore,the electrolyte exhibits excellent high-temperature characteristics when used in a 1-Ah pouch cell(N/P=0.26),and higher thermal runaway temperature(238℃)in the ARC(accelerating rate calorimeter)demonstrating high safety.This novel electrolyte adopts long-chain phosphate as the main solvent for the first time,and would provide a new idea for the development of extremely high safety and high-temperature electrolytes. 展开更多
关键词 Non-flammable electrolyte Long chain phosphate ester Solvation structure Lithium metal batteries Battery safety
下载PDF
Molecular Modeling of the Chain Structures of Polybenzoxazines 被引量:3
3
作者 LIU Xin GU Yi 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2002年第3期367-369,共3页
The structures and properties of benzoxazines were investigated by virtue of molecular modeling at a molecular level. By means of Cerius software(version 4.0) supplied by Molecular Simulations Inc., the molecular mech... The structures and properties of benzoxazines were investigated by virtue of molecular modeling at a molecular level. By means of Cerius software(version 4.0) supplied by Molecular Simulations Inc., the molecular mechanics and the molecular dynamics were performed under a PCFF force field. Five kinds of the polymeric chains of benzoxazines were created by using polymer builder and energy minimization. The relaxation process was conducted with both energy minimization and molecular dynamics. 展开更多
关键词 POLYBENZOXAZINES chain structure Molecular mechanics Molecular dynamics Quantum dynamics
下载PDF
A Multi-level Approach for Complex Fault Isolation Based on Structured Residuals 被引量:4
4
作者 叶鲁彬 石向荣 梁军 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2011年第3期462-472,共11页
In industrial processes,there exist faults that have complex effect on process variables.Complex and simple faults are defined according to their effect dimensions.The conventional approaches based on structured resid... In industrial processes,there exist faults that have complex effect on process variables.Complex and simple faults are defined according to their effect dimensions.The conventional approaches based on structured residuals cannot isolate complex faults.This paper presents a multi-level strategy for complex fault isolation.An extraction procedure is employed to reduce the complex faults to simple ones and assign them to several levels.On each level,faults are isolated by their different responses in the structured residuals.Each residual is obtained insensitive to one fault but more sensitive to others.The faults on different levels are verified to have different residual responses and will not be confused.An entire incidence matrix containing residual response characteristics of all faults is obtained,based on which faults can be isolated.The proposed method is applied in the Tennessee Eastman process example,and the effectiveness and advantage are demonstrated. 展开更多
关键词 multi-level structured residuals principal component analysis complex fault isolation Tennessee Eastman process
下载PDF
Effect of salt solutions on chain structure of partially hydrolyzed polyacrylamide 被引量:2
5
作者 张青 周吉生 +2 位作者 翟永爱 刘凤岐 高歌 《Journal of Central South University》 SCIE EI CAS 2008年第S1期80-83,共4页
The effect of salt solutions(NaCl,Na2SO4 and CaCl2) on the conformational properties of partially hydrolyzed polyacrylamide(HPAM) was investigated by using static laser light scattering(SLLS).The special interaction b... The effect of salt solutions(NaCl,Na2SO4 and CaCl2) on the conformational properties of partially hydrolyzed polyacrylamide(HPAM) was investigated by using static laser light scattering(SLLS).The special interaction between CaCl2 solution and HPAM was also researched.Experimental results show that the chain structure of HPAM is interrelated with the charge density,the kind and the concentration of salt solutions.The mean-square radius of gyration(Rz) and the second virial coefficient(A2) of HPAM decrease with increasing concentration of salt solutions,and the salt effect tends towards the maximum when the concentration of salt solution is increased to some amount. 展开更多
关键词 PARTIALLY hydrolyzed polyacrylamide(HPAM) SALT EFFECT chain structure static laser light scattering(SLLS)
下载PDF
Structures of Textile-apparel Supply Chain: Concepts and Cases 被引量:3
6
作者 曹宁 张志明 +1 位作者 Kin Man To Chester Keng Po Ng Roger 《Journal of Donghua University(English Edition)》 EI CAS 2005年第2期130-134,共5页
In recent years, supply chain management (SCM) has been in popularity as a new management philosophy for all industries, including textile and apparel industries. The textile-apparel supply chain is relatively compl... In recent years, supply chain management (SCM) has been in popularity as a new management philosophy for all industries, including textile and apparel industries. The textile-apparel supply chain is relatively complex because it encompasses many participants such as yarn manufacturers, fabric manufacturers, garment manufacturers and retailers. Although many scholars are engaged in researching SCM in textile and apparel industries, a systematic classification of textile-apparel chain does not exist. The paper proposes three types of textile-apparel chain, nominated vertical integration chain, traditional sourcing chain and 3P-hub (third party as the hub) chain. Different coordinators exist in different types of chain. Three Hong Kong headquartered companies, Esquel Group, TAL Apparel Ltd., and Li & Fang (Trading) Ltd. are used as cases responding to each type of the structures respectively. 展开更多
关键词 supply chain textile-apparel chain COORDINATOR structure
下载PDF
Synthesis and Crystal Structure of 1D Chloride Bridged Cadmium(Ⅱ) Chain
7
作者 欧光川 《湖南科技学院学报》 2005年第5期113-115,共3页
Hydrothermal reaction of 1,10-phenanthroline with CdCl2·2.5H2O in aqueous solution leads to the complex of [Cd(μ-Cl)2(phen)]n (phen = 1-10-phenanthroline). The crystal structure has been determined by X-ray anal... Hydrothermal reaction of 1,10-phenanthroline with CdCl2·2.5H2O in aqueous solution leads to the complex of [Cd(μ-Cl)2(phen)]n (phen = 1-10-phenanthroline). The crystal structure has been determined by X-ray analysis. It crystallizes in monoclinic with space group C2/c, a = 16.947(3), b = 10.529(2), c = 7.235(1) , β = 110.795(3)°, V = 1208.8(3) 3, Z = 4, Dc = 1.997 g.cm-3, μ= 2.22 mm-1, F(000) = 704, R = 0.0231, Rw = 0.0626 for 1194 reflections with I > 2σ (I). In the crystal structure, the [Cd(phen)]2+ units are bridged by chloride ions to form 1D chain. The 1D chains combine through π……π interactions of phen groups to form 2D infinite molecular zipper. 展开更多
关键词 合成反应 晶体结构 氯化镉 钱恩
下载PDF
Structural Stabilities and Electronic Structures of Ga Atomic Chains 被引量:2
8
作者 Shun-qing Wu Guo-zhen Chen Zi-zhong Zhu 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2006年第3期219-222,共4页
The structural stabilities and electronic structures of Ga atomic chains are studied by the first-principles plane wave pseudopotential method based on the density functional theory. The present calculations show that... The structural stabilities and electronic structures of Ga atomic chains are studied by the first-principles plane wave pseudopotential method based on the density functional theory. The present calculations show that gallium can form planar chains in linear-, zigzag- and ladder-form one-dimensional structures. The most stable one among the studied structures is the zigzag chain with a unit cell rather close to equilateral triangles with four nearest neighbors, and all the other structures are metastable. The relative structural stability, the energy bands and the charge densities are discussed based on the ab initio calculations and the Jahn-Teller effect. 展开更多
关键词 Ga atomic chains structural stability Electronic structures ab initio
下载PDF
Effects of Irradiation on the Structure-activity Relationship of Konjac Glucomannan Molecular Chain Membrane 被引量:1
9
作者 吴春华 彭述辉 +6 位作者 温成荣 王丽霞 熊波 刘雅楠 范琳琳 姚闽娜 庞杰 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2012年第6期857-866,共10页
To know the effects of irradiation on the konjac glucomannan (KGM) molecular chain membrane, KGM membrane solution was treated with the irradiation dose of 0-20 kGy in this study, and the structure and properties of... To know the effects of irradiation on the konjac glucomannan (KGM) molecular chain membrane, KGM membrane solution was treated with the irradiation dose of 0-20 kGy in this study, and the structure and properties of KGM membrane were analyzed with Infrared spectrum, Raman spectrum, X-ray, SEM scanning and so on. The results revealed that the effects of different irradiation doses on the KGM molecular chain structure were different. Higher irradiation dose (20 kGy) resulted in partial damage against KGM membrane crystal structure, and there was no obvious change for the amorphous structure; with membrane property test, the tensile strength of KGM membrane gradually increased with the increase of irradiation dose and its elongation at break reduced, but these changes were not significant, WVP value reduced; with SEM, the membrane surface treated with irradiation was smoother even than the membrane without treatment. In addition, when increasing the irradiation dose, membrane surface became more even, and arrangement was more orderly and compact. KGM membrane nrooerties, and it is an ideal Irradiation modification could effectively improve the modification method. 展开更多
关键词 KGM molecular chain irradiation modification membrane structure MECHANICALPROPERTY
下载PDF
Design,Synthesis and Crystal Structure of Two One-dimensional Zigzag Chain-like Compounds 被引量:1
10
作者 秦政涛 盛天录 +5 位作者 胡胜民 项生昌 傅瑞标 王欣 沈超君 吴新涛 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2008年第8期1013-1019,共7页
Two one-dimensional chain-like cyanide-bridged compounds, [Fe(Phen)2(CN)2Ni(Cyclam)](ClO4)2·DMF-2H2O 1 (Cyclam = 1,4,8,11-tetraaza-cyclotetradecane, Phen = 1,10-phenanthroline, and DMF = N,N-dimethylform... Two one-dimensional chain-like cyanide-bridged compounds, [Fe(Phen)2(CN)2Ni(Cyclam)](ClO4)2·DMF-2H2O 1 (Cyclam = 1,4,8,11-tetraaza-cyclotetradecane, Phen = 1,10-phenanthroline, and DMF = N,N-dimethylformamide) and [Fe(Phen)2(CN)2Zn(Cyclam)](PF6)2·CH3CN 2, were prepared by the reaction of [Fe(Phen)2(CN)2]·2H2O with M(Cyclam)^2+ (M = Ni, Zn). In complexes 1 and 2, the metal atoms are connected alternatively with CN groups. X-ray structure and IR analyses for 1 and 2 were performed. Structure analysis revealed that both complexes are centrosymmetric and the geometry around each metal atom is an octahedron. The two complexes crystallize in triclinic with space group of P^1-. For 1, a = 10.439(4), b = 14.976(7), c = 15.914(8)A,α = 83.168(15), β = 74.338(15), γ = 78.023(15)°, V = 2338.3(18)A^3, Z = 2, Mr = 1035.37, Dc = 1.471 g/cm^3, F(000) = 1076,μ = 0.895 mm^-1, the final R = 0.0616 and wR = 0.1414 for 5849 observed reflections (1 〉 2σ(I)). For 2, a = 9.656(6), b = 15.404(9), c = 15.822(10)A, α = 78.68(2), β= 78.917(19), γ = 77.15(2)°, V = 2223(2)A^3, Z = 2, Mr = 1064.87, Dc = 1.587 g/cm^3, F(000) = 1078,μ = 1.032 mm^-1, the final R = 0.0672 and wR = 0.1595 for 6819 observed reflections (I 〉 2σ(I)). 展开更多
关键词 CN bridge iron crystal structure zigzag chain π-π stacking
下载PDF
SYNTHESIS AND CHARACTERIZATION OF AMPHIPHILIC GRAFT COPOLYMER CONTAINING MICROPHASE SEPARATED AND LONG POLY(ETHYLENE OXIDE) SIDE CHAIN STRUCTURES 被引量:4
11
作者 邱永兴 俞小洁 +1 位作者 封麟先 杨士林 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1993年第1期67-75,共9页
Acryloyl terminated Poly (ethyleneoxide)macromonomers (PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (e... Acryloyl terminated Poly (ethyleneoxide)macromonomers (PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (ethylene oxide)graft copolymer containing both microphase separated and PEO side chain structures has been synthesized from radical copolymerization of PEO-A macromonomer with styrene. After careful purification by a newly-developed method called 'selective dissolution', the well-defined structure of the purified copolymers was confirmed by IR, ~1H-NMR and GPC. Various experimental parameters controlling the copolymerization were studied in detail. The results indicated that the feed ratio of styrene to macromonomer(S/M) was the most important determining factor for the composition of the copolymers. A detailed 'comb- model' was proposed to describe the molecular structure of the graft copolymers. Finally, this amphiphilic graft copolymers may readily form microphase separated structures as clearly indicated by transmission electron microscopy. 展开更多
关键词 PEO AIBN SIDE chain structureS SYNTHESIS AND CHARACTERIZATION OF AMPHIPHILIC GRAFT COPOLYMER CONTAINING MICROPHASE SEPARATED AND LONG POLY ETHYLENE OXIDE PS
下载PDF
Analysis on the Structure of Influencing Factors of Sustainable Supply Chain Implementation of Water Diversion Project 被引量:3
12
作者 Meng Liu Liwei Yang Tongsheng Liu 《Journal of Geoscience and Environment Protection》 2021年第8期140-150,共11页
The systematic analysis of the hierarchical relationship among the factors affecting the sustainable supply chain implementation of water diversion projects has theoretical value and practical significance for the sus... The systematic analysis of the hierarchical relationship among the factors affecting the sustainable supply chain implementation of water diversion projects has theoretical value and practical significance for the sustainable development of large-scale water diversion projects. Through the investigation of relevant literature, books, web pages, materials, and discussions with relevant experts and scholars, a total of 23 factors influencing the sustainable supply chain implementation of water diversion projects were identified. Then using ISM (Interpretative Structural Modeling Method) to analyze the causality of each factor, a multi-level hierarchical structure model was obtained. The results showed that: 1) The surface-level influencing factors of the sustaina<span>ble supply chain implementation of the water diversion project mainly i</span>ncluded 8 factors such as water-saving awareness and water-saving intensity in the diversion area, water quality, water pollution and other disasters, effective incentive mechanisms, etc., and surface-level influencing factors were directly related to the sustainable supply chain implementation of water diversio<span>n projects. 2) The indirect influencing factors of the sustainable supply chai</span>n of water diversion projects included 12 factors such as the water quality and quantity guarantee rate of the supply chain, the government’s enforcement of laws and regulations, water distribution, ecological compensation, and compensatio<span>n mechanisms for residents in the water source area. Indirect influencing</span> factor scan acts directly on the direct influencing factors, and int<span>ervening in the factors that can be controlled by humans is one of the important ways to improve the sustainable operation of water diversion proj</span><span>e</span><span>cts. 3) T</span><span>he fundamental influencing factors for the sustainable supply chain implementation of water diversion projects included three f</span>actors: Resettlement policy, government financial support, and sound laws and regulations. Deep influencing factors had multi-channel influence and controllability, and intervening in them was the main means to improve the sustainable operation of water diversion projects. 展开更多
关键词 Water Diversion Project Sustainable Supply chain Interpretative structural Modelling Method Hierarchical structure Model
下载PDF
Improved Fibroblast Adhesion and Proliferation by Controlling Multi-level Structure of Polycaprolactone Microfiber 被引量:1
13
作者 JIAO Yongjie LI Chaojing +3 位作者 LI Qiwei LIU Laijun WANG Fujun WANG Lu 《Journal of Donghua University(English Edition)》 EI CAS 2020年第4期280-285,共6页
Improving wound healing efficiency is a key issue for high performance dressings.The surface topology of fibers in wound dressings plays an important role in regulating cell behaviors during the regeneration.Herein,a ... Improving wound healing efficiency is a key issue for high performance dressings.The surface topology of fibers in wound dressings plays an important role in regulating cell behaviors during the regeneration.Herein,a polycaprolactone(PCL)scaffold with a shish-kebab structure was prepared by electrospinning and solution-induced crystallization.L929 cells were used to investigate the behavior of fibroblasts on the multi-level microfiber.The results showed that the shish-kebab fiber-based scaffold enhanced the cell proliferation when compared with the normal fiber and the fiber with a porous structure.Protein absorption,cell adhesive force,and cell modulus also increased by the shish-kebab fiber.The shish-kebab fiber-based scaffold with improved fibroblast-regulation ability can be applied in rapid wound healing. 展开更多
关键词 cell-regulation multi-level microfiber shish-kebab structure electrospinning surface
下载PDF
Synthesis and Crystal Structure of 1-D Chain Copper(Ⅱ) Complex: [Cu(L)Cl_2]_n (L=2,5-Di-2-pyridyl-1,3,4-oxodiazole) 被引量:1
14
作者 李建荣 郭国聪 +1 位作者 卜显和 黄锦顺 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2004年第2期141-144,共4页
The title complex, [Cu(L)Cl2]n (L = 2,5-di-2-pyridyl-1,3,4-oxodiazole) 1, has been obtained from the reaction of 3,6-di-2-pyridyl-1,2,4,5-tetrazine (bptz) and CuCl2?H2O in a mixture solvent of CH3CN and CH2Cl2 (L is g... The title complex, [Cu(L)Cl2]n (L = 2,5-di-2-pyridyl-1,3,4-oxodiazole) 1, has been obtained from the reaction of 3,6-di-2-pyridyl-1,2,4,5-tetrazine (bptz) and CuCl2?H2O in a mixture solvent of CH3CN and CH2Cl2 (L is generated from the metal-assisted hydrolysis reaction of bptz) and structurally characterized. It crystallizes in space group C2/c of monoclinic system with cell parameters: a = 9.812(2), b = 12.679(3), c = 11.111(2) ? b = 103.92(3)? V = 1341.6(5) 3, Z = 4, Dc = 1.776 g/cm3, Mr = 358.66, F(000) = 716, ?= 2.024 mm1 and S = 1.004. The final R = 0.0346 and wR = 0.0938 for 1011 observed reflections with I > 2(I). The Cu(Ⅱ) ion is six-coordinated by four N atoms of two L ligands and two Cl ions in a distorted octahedral geometry. The ligand L acts as a bis-bidentate ligand to bridge the Cu(Ⅱ) ions, resulting in an infinite chain structure. 展开更多
关键词 copper(Ⅱ) complex synthesis crystal structure 1-D chain
下载PDF
MORPHOLOGY EVOLUTION IN PTFE AS A FUNCTION OF MELT TIME AND TEMPERATURE——Ⅱ.LOW MOLECULAR WEIGHT FOLDED CHAIN SINGLE CRYSTALS AND BAND STRUCTURES
15
作者 J.YangandP.H.Geil T.C.LongandP.Xu 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2005年第2期137-145,共9页
The effect of sintering dispersed and bulk,low molecular weight(M_n=50,000 Da),nano-emulsionpolytetrafluoroethylene(PTFE)particles near their melting point is described.With the nascent particles consisting of ca.75 n... The effect of sintering dispersed and bulk,low molecular weight(M_n=50,000 Da),nano-emulsionpolytetrafluoroethylene(PTFE)particles near their melting point is described.With the nascent particles consisting of ca.75 nm diameter,hexagonal,single crystals,sintering at,e.g.,350℃,results,initially,in merger of neighboring particles,followed by individual molecular motion on the substrate and the formation of folded chain,lamellar single crystals andspherulites,and on-edge ribbons.It is suggested these structures develop,with time,in the mesomorphic“melt”.Sintering ofthe bulk resin yields extended chain,band structures,as well as folded chain lamellae;end-surface to end-surface merger,possibly by end-to-end polymerization,occurs with increasing time. 展开更多
关键词 Polytetrafluoroethylene NANO-EMULSION Single crystals SPHERULITES Banded structures Extended chain crystals Sintering.
下载PDF
Energetics and electronic structure of a single copper atomic chain wrapped in a carbon nanotube:a first-principles study
16
作者 张建民 杜秀娟 +1 位作者 王素芳 徐可为 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第12期5468-5473,共6页
In the generalized gradient approximation, the energy and electronic structure are investigated for a single copper atomic chain wrapped in (4, 4), (5, 5) and (6, 6) armchair carbon nanotubes by using the first-... In the generalized gradient approximation, the energy and electronic structure are investigated for a single copper atomic chain wrapped in (4, 4), (5, 5) and (6, 6) armchair carbon nanotubes by using the first-principles projector-augmented wave potential within the framework of density functional theory. The results show that the (4, 4) and (5, 5) tubes are too narrow to wrap a Cu chain, but the (6, 6) tube is nearly ideal to wrap a Cu chain on its centre axis. Wider tubes are anticipated to wrap more than one Cu chain spontaneously with forces amounting to a fraction of a nanonewton. Although the tube-chain interaction decreases with the increase of the tube diameter of (4, 4), (5, 5) and (6, 6) successively, the charge density of the Cu@(6, 6) combined system still does not show complete superposition of that of the pristine (6, 6) tube and Cu chain. Successively reducing the restrictions of (4, 4), (5, 5) and (6, 6) tubes on the Cu chain leads to a reduction in shift of the highest peak of the Cu chain towards lower energies, that is from -0.5177 eV of the isolated Cu chain to -1.36785 eV, -0.668 eV and -0.588 eV for the Cu@(4, 4), Cu@(5, 5) and Cu@(6, 6) systems, respectively. In reverse, the strong metallic character of the Cu chain also enhances the metallic character of the combined systems so that the broader pseudogaps of the pristine carbon nanotubes around the Fermi level change into the narrow pseudogaps of the combined systems. 展开更多
关键词 copper atomic chain carbon nanotube electronic structures FIRST-PRINCIPLE
下载PDF
Structures and magnetic properties of Fe and Ni monoatomic chains encapsulated by an Au nanotube
17
作者 韩志东 李秀燕 +3 位作者 杨致 刘瑞萍 刘绍鼎 张莹 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第11期495-499,共5页
Structures and magnetic properties of transition metal (TM) Fe or Ni monoatomic chains (MACs) encapsulated by a Au (5, 5) nanotube (Fe@Au and Ni@Au) are investigated using the density functional theory (DFT)... Structures and magnetic properties of transition metal (TM) Fe or Ni monoatomic chains (MACs) encapsulated by a Au (5, 5) nanotube (Fe@Au and Ni@Au) are investigated using the density functional theory (DFT). The calculated results show that both Fe@Au and Ni@Au prefer to adopt ferromagnetic (FM) orders as ground states. In particular, the Fe@Au keeps the magnetic properties of free-standing Fe MAC, indicating that this system may be viewed as a new candidate in electromagnetic devices. 展开更多
关键词 transition metal monoatomic chains Au nanotube structure magnetic property
下载PDF
Synthesis and Crystal Structure of One-dimensional Chain Complexes [K(18-C-6)]_2[M(mnt)_2](M=Zn,Hg)
18
作者 WANGDa-qi HEGuo-fang +1 位作者 QIULin-lin DOUJian-min 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2003年第3期263-268,共6页
The reactions of 18 crown 6 with each of K 2(M=Zn, Hg; mnt=1,2 dicyanoethene 1,2 dithiolate, C 2S 2(CN) 2- 2) were studied and novel complexes [K(18 C 6)] 2[Zn(mnt) 2](1) and [K(18 C 6)] 2[Hg(mnt)... The reactions of 18 crown 6 with each of K 2(M=Zn, Hg; mnt=1,2 dicyanoethene 1,2 dithiolate, C 2S 2(CN) 2- 2) were studied and novel complexes [K(18 C 6)] 2[Zn(mnt) 2](1) and [K(18 C 6)] 2[Hg(mnt) 2](2) were characterized by elemental analysis, IR spectrum and X ray diffraction analysis. Complex 1 displays a one dimensional chain of [K(18 C 6)] 2[Zn(mnt) 2] bridged by K O interactions between adjacent [K(18 C 6)] + units. Complex 2 is also a one dimensional chain of [K(18 C 6)] 2[Hg(mnt) 2] bridged by K...S weak interactions between adjacent [K(18 C 6)] + and [Hg(mnt) 2] 2- . 展开更多
关键词 One dimensional chain Crown ether mnt complex 18 Crown 6 Crystal structure
下载PDF
Differences in Starch Chain Length Distribution and Structure Characteristics of Early-Indica Rice Under Different Temperature Treatments During Grain-Filling
19
作者 ZHONGLian-jin CHENGFang-min +1 位作者 ZHANGGuo-ping SUNZong-xiu 《Agricultural Sciences in China》 CAS CSCD 2005年第1期21-25,共5页
Effects of temperature during grain-filling on chain length distribution and structure characteristics of 4 early-seasonindica rice cultivars were investigated under the environment-controlled conditions. The plants a... Effects of temperature during grain-filling on chain length distribution and structure characteristics of 4 early-seasonindica rice cultivars were investigated under the environment-controlled conditions. The plants at flowering stage weresubjected to two temperature treatments until maturity (the mean dairy air temperature, 22 and 32C for optimum temperaturetreatment and high temperature treatment, respectively). The result showed that high temperature during grain-fillingsignificantly decreased the long B-chain content and increased the intermediate B-chain content. But the effect of hightemperature on other starch chains appeared to be cultivar-dependant. The crystalline characteristics of rice starch werealso affected by temperature during grain-filling. The intensity at 18 2q of X-ray diffraction pattern of rice samples underhigh temperature was higher than those under optimum temperature, though all rice starches performed A-crystallinetype. Moreover, the intensity at 18 2q was positive correlation with intermediate B-chain content and negative correlationwith long B-chain content. 展开更多
关键词 Rice (Oryza sativa L.) Temperature STARCH chain length distribution Crystalline structure
下载PDF
Multi-level Flocculation Structures of Fresh Cement Paste by Confocal Laser Scanning Microscope
20
作者 张力冉 王栋民 ZHANG Weili 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第2期302-308,共7页
Under saturation dosage of all kinds of SP, the free water amount was examined by centrifuge. The distribution of solution and flocculation microstructures in fresh cement paste was observed in three- dimensional spac... Under saturation dosage of all kinds of SP, the free water amount was examined by centrifuge. The distribution of solution and flocculation microstructures in fresh cement paste was observed in three- dimensional space by confocal laser scanning microscope(CLSM). Results indicate that SP can increase the free water amount by destroying the flocculated cement particle structure and different free water amount is released by different kinds of SP. The changes of the size of flocculation structures and the dispersion of solution were obviously detected with confocal laser scanning microscope: the size of flocculation structures was smaller and more dispersed in fresh cement paste with polycarboxylate superplasticizer, but the size of flocculation structures was bigger and cannot be dispersed uniformly in fresh cement paste with others SP. The multi- level flocculation structures theoretical model of fresh cement paste was then set up. The theory indicates that different kinds of SP with different dispersion strength will open the flocculation structures at different levels, which in turn present different water reducing rate. 展开更多
关键词 multi-level flocculation structure CLSM SP free water amount
下载PDF
上一页 1 2 154 下一页 到第
使用帮助 返回顶部