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Local Structure Determination of Mn^(2+)-Doped Fluoride Crystals by Superhyperfine Splitting Measurements

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Chinese Physics Letters 1998年第1期15卷 43-45页

作者：赵敏光 Institute of Solid State Physics Sichuan Normal UniversityChengdu 610068

A procedure is presented for the calculation of the Mn^(2+)-F^(-) bond length from the superhyperfine constants measured by magnetic resonance experiments.With the present technique it is possible to detect the variation of the bond length,ΔR,down to 0.01Å.The technique is sensitive enough to determine the bond length R and its variationΔR experienced when pressure or temperature changes.

关键词： hyperfine constants bond

Hand-holding and releasing between the anion and cation to change their macroscopic behavior in water

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Green Energy & Environment 2019年第2期4卷 127-130页

作者： Kosuke Kuroda Yumiko Shimada Kenji Takahashi Faculty of Biological Science and Technology Institute of Science and Engineering Kanazawa University

Despite the similarity of ionic liquid and zwitterion, their some properties such as conductivity and hydrophobicity are different. Here we developed a novel phosphonium salt having a dynamic covalent bond between anion and cation, enabling reversible structural shift between free ion pair and zwitterion. With the phosphonium salt, control of the macroscopic phase behavior in aqueous solution, i.e. forming mono-or biphasic systems, upon exposure to an acid or base was reversibly achieved, based on the structural shift of the phosphonium salt. CO_2/N_2 bubbling reversibly changed the phase behavior as well as acid/base, leading to green separation systems.

关键词： Ionic liquid Zwitterion Phase separation Dynamic covalent bond

Size of Defect Clusters in Lithium Niobate Single Crystals

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Journal of Rare Earths 2006年第Z1期24卷 253-256页

作者： He Xiangke Xue Dongfeng State Key Laboratory of Fine Chemicals Department of Materials Science and Chemical Engineering School of Chemical Engineering Dalian University of Technology Dalian 116012 China Key Laboratory for Micro/Nano Technology and System of Liaoning Province Dalian University of Technology Dalian 116023 China State Key Laboratory of Fine Chemicals Department of Materials Science and Chemical Engineering Key Laboratory for Micro/Nano Technology and System of Liaoning Province Dalian University of Technology Dalian 116023 China

On the basis of the Li-site vacancy model, the non-stoichiometric defects in LN crystals, i.e., anti-site defects NbLi and corresponding lithium vacancy defects VLi, were investigated by the bond valence model. According to the valence sum rule, 4 VLi sites must emerge in the nearest lattices of NbLi, and thus form a neutral cluster with the center, NbLi(VLi)4Nb5O15. The bond graph of the defect cluster was given, which reveals the ideal chemical bonding characteristics of defect clusters. Combining the possible configuration of defect clusters and the ideal bond lengths in the bond graph, the size of defect clusters in the LN crystallographic frame is estimated as 0.9～1.2 nm in diameter.

关键词： lithium niobate defect cluster defect size bond valence model

bond valence parameters linearly dependent on the molybdenum oxidation states

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Chinese Science Bulletin 2002年第12期47卷 978-981页

作者： Mingdan Chen Zhaohui Zhou Shengzhi Hu Xiamen Univ Dept Chem Inst Chem Phys State Key Lab Phys Chem Solid Surfaces Xiamen 361005 Peoples R China

Based on the available crystal data, a linear correlation between R0, the bond valence parameter for a Mo-containing chemical bond, and the Mo oxidation state n was developed for the first time. Using the 'universal' value of the parameter B = 0.037 nm, the linear equations of R0-n for Mo-X (X: O, S, N, Cl and F) bonds were established. The oxidation-state independent Mo-O bond valence parameters, R0 = 0.18788 nm and B = 0.03046 nm, published recently have been shown to be a special case of the linearly correlated functions. Some bond valence sum calculations in compounds containing only Mo-O bonds using these parameters are presented.

关键词： bond valence parameter Mo-O bond oxidation state valence sum rule.

Strong dual-crosslinked hydrogels for ultrasound-triggered drug delivery

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Nano Research 2019年第1期12卷 115-119页

作者： Wenxu Sun Heting Jiang Xin Wu Zhengyu Xu Chen Yao Juan Wang Meng Qin Qing Jiang Wei Wang Dongquan Shi Yi Cao Collaborative Innovation Center of Advanced Microstructures National Laboratory of Solid State Microstructureand Department of PhysicsNanjing UniversityNanjing 210093China Department of Sports Medicine and Adult Reconstructive surgery Drum Tower HospitalMedical SchoolState Key Laboratory of Analytical Chemistry for Life ScienceNanjing UniversityNanjing 210008China Joint Research Center far Bone and Joint Disease Model Animal Research Center(MARC)School of Chemistry and Chemical Engineeringand State Key Laboratory of Analytical Chemistry far Life ScienceNanjing UniversityNanjing 210093China

Hydrogels that can respond to dynamic forces either from endogenous biological activities or from external mechanical stimuli show great promise as novel drug delivery systems (DDS).However,it remains challenging to engineer hydrogels that specifically respond to externally applied mechanical forces with minimal basel drug leakage under normal stressful physiological conditions.Here we present an ultrasound responsive hydrogel-based DDS with special dual-crosslinked nanoscale network architecture.The covalent crosslinks endow the hydrogel high mechanical stability and greatly suppress deformation-triggered drug release.Meanwhile,the dynamic covalent boronate ester linkages between hydrogel backbone and the anti-inflammation compound,tannic acid (TA),allow effective ultrasound-triggered pulsetile release of TA.As such,the hydrogel shows distinct drug release profiles under compression and ultrasound.A proof-of-principle demonstration of the suppression of inflammation activation of macrophage upon ultrasound-triggered release of TA was also illustrated.We anticipate that this novel hydrogel-based drug delivery system can be used for the treatment of inflammatory diseases on load-bearing tissues,such as muscle and cartilage.

关键词： hydrogel dynamic covalent bond mechanical force drug release

INTERFACIAL REACTIONS OF THE EXPLOSIVELY WELDED TITANIUM-STEEL COMPOSITE DURING HEAT TREATMENT

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中国有色金属学会会刊：英文版 1997年第2期7卷 83-86页

作者： Xia, Changqing Jin, Zhanpeng Central South Univ of Technology Changsha China

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关键词： titanium steel bond interface microstructure diffusion path

Aggregation and assembly of crescent foldamers

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Science China Chemistry 2010年第1期53卷 45-51页

作者： GONG Bing Department of Chemistry,University at Buffalo,The State University of New York,Buffalo,New York 14260,USA Department of Chemistry University at Buffalo The State University of New York Buffalo USA

Recent studies have started to provide initial insights into the aggregation and assembly of two classes of back-rigidified foldamers with flat,curved backbones consisting of aromatic residues.With their persistent shape that presents large,well-defined aromatic surface areas,these crescent foldamers were found to undergo size-dependent aggregation in solution and pack into 1D assemblies in the solid state.Crescent aromatic oligoamides undergo stacking interactions not only in polar solvents but also in nonpolar ones,a unique property that is not associated with many other molecules that associate via π-π stacking interaction.The stacking of oligo(m-phenylene ethynylenes) is similar to aromatic hydrocarbons,being promoted in polar solvents such as methanol while being discouraged in nonpolar solvents such as halohydrocarbons.The ready synthetic availability of crescent foldamers makes it possible to directly control the intermolecular interaction by tuning surface areas.Besides,the columnar assembly of these cavity-containing molecules provides a new strategy for constructing supramolecular nanotubular structures.

关键词： foldamer folding hydrogen bond π-π stacking aggregation assembly

Dopant Occupancy in MgO-Codoped Lithium Niobate Crystals

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Journal of Rare Earths 2006年第Z1期24卷 276-280页

作者： He Xiangke Xue Dongfeng State Key Laboratory of Fine Chemicals Department of Materials Science and Chemical Engineering School of Chemical Engineering Dalian University of Technology Dalian 116012 China Key Laboratory for Micro/Nano Technology and System of Liaoning Province Dalian University of Technology Dalian 116023 China State Key Laboratory of Fine Chemicals Department of Materials Science and Chemical Engineering School of Chemical Engineering Dalian University of Technology Dalian 116012 China Key Laboratory for Micro/Nano Technology and System of Liaoning Province Dalian University of Technology Dalian 116023 China

On the basis of the bond valence model, the preferential occupancy of various dopant such as Mn2+, Eu3+, Er3+, Nd3+, Lu3+, Yb3+, In3+, Cr3+, Fe3+ and Ti4+ in the ideal stoichiometric lithium niobate (SLN) crystallographic frame was investigated in a viewpoint of chemical bonds. Theoretical analysis indicates that the dopant occupancy is significantly influenced by the anti-site Nb4+Li. Our work also shows that Mg-like ions (Mg2+, Zn2+, In3+, Sc3+) have a repulsive effect on Nb4+Li ions. When removing Nb4+Li ion by codoping Mg-like ions, the dopant occupancy in the LN crystallographic frame is determined by the natural characteristics of dopant, which is consistent well with the result in the ideal SLN crystals.

关键词： lithium niobate bond valence model codoping dopant occupancy

The open-close mechanism of M2 channel protein in influenza A virus:A computational study on the hydrogen bonds and cation-π interactions among His37 and Trp41

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Science China Chemistry 2008年第8期51卷 768-775页

作者： CHENG JiaGao ZHU WeiLiang WANG YanLi YAN XiuHua LI Zhong TANG Yun JIANG HuaLiang School of Pharmacy East China University of Science and TechnologyShanghai 200237China Drug Discovery and Design Center Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China School of Sciences East China University of Science and TechnologyShanghai 200237China

The M2 protein from influenza A virus is a tetrameric ion channel. It was reported that the permeation of the ion channel is correlated with the hydrogen bond network among His37 residues and the cation-π interactions between His37 and Trp41. In the present study,the hydrogen bonding network of 4-methyl-imidazoles was built to mimic the hydrogen bonds between His37 residues,and the cation-π interactions between 4-methyl-imidazolium and indole systems were selected to represent the interac-tions between His37 and Trp41. Then,quantum chemistry calculations at the MP2/6-311G level were carried out to explore the properties of the hydrogen bonds and the cation-π interactions. The calcula-tion results indicate that the binding strength of the N-H···N hydrogen bond between imidazole rings is up to -6.22 kcal·mol-1,and the binding strength of the strongest cation-π interaction is up to -18.8 kcal·mol-1(T-shaped interaction) or -12.3 kcal·mol-1(parallel stacking interaction). Thus,the calcu-lated binding energies indicate that it is possible to control the permeation of the M2 ion channel through the hydrogen bond network and the cation-π interactions by altering the pH values.

关键词： cation-π interaction hydrogen bond noncovalent interaction ab initio calculation M2 protein