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An R(x)-orthonormal theory for the vibration performance of a non-smooth symmetric composite beam with complex interface

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Acta Mechanica Sinica 2019年第1期35卷 228-241,I0007页

作者： Chein-Shan Liu Bo-Tong Li College of Mechanics and Materials Hohai UniversityNanjing 210098China Center of Excellence for Ocean Engineering Department of Mechanical and Mechatronic EngineeringTaiwan Ocean UniversityKeelung 202-24China School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China

A composite beam is symmetric if both the material property and support are symmetric with respect to the middle point. In order to study the free vibration performance of the symmetric composite beams with different complex nonsmooth/discontinuous interfaces, we develop an R(x)-orthonormal theory, where R(x) is an integrable flexural rigidity function. The R(x)-orthonormal bases in the linear space of boundary functions are constructed, of which the second-order derivatives of the boundary functions are asked to be orthonormal with respect to the weight function R(x). When the vibration modes of the symmetric composite beam are expressed in terms of the R(x)-orthonormal bases we can derive an eigenvalue problem endowed with a special structure of the coefficient matrix A :=[aij ],aij= 0 if i + j is odd. Based on the special structure we can prove two new theorems, which indicate that the characteristic equation of A can be decomposed into the product of the characteristic equations of two sub-matrices with dimensions half lower. Hence, we can sequentially solve the natural frequencies in closed-form owing to the specialty of A. We use this powerful new theory to analyze the free vibration performance and the vibration modes of symmetric composite beams with three different interfaces.

关键词： Symmetric composite beams R(x)-orthogonality of second-order derivatives of boundary functions R(x)-orthonormal theory Non-smooth/discontinuous interface Sequentially closed-from natural frequencies

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supported carbon dots decorated with metallothionein for selective cadmium adsorption and removal

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Chinese Chemical Letters 2015年第12期26卷 1496-1501页

作者： Ting Yang Yi-Kun Li Ming-Li Chen Jian-Hua Wang research Center for Analytical Sciences College of Sciences Northeastern University

Carbon dots are prepared and immobilized onto spherical SiO_2 through a one-step thermal oxidation and then decorated with metallothionein（MT）, a protein with high affinity towards thiophilic metals. The MT-carbon dots composites are characterized by means of FT-IR, SEM and TGA, giving rise to a MT loading amount of 823 μg g^（-1）. The adsorption of cadmium by the composites is a fast process and follows Langmuir model. In comparison with native SiO_2, a 2- and 2.4-folds improvement on the static and dynamic adsorption capacity of the composites for cadmium are obtained, respectively. Moreover,the adsorption efficiency is not affected by the presence of other metals. Finally, the composites are successfully applied for the removal of cadmium in a series of environmental water samples.

关键词： cadmium adsorbent spherical kinetics isotherms sorption breakthrough effluent alkaline sequential

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Recent advances in chemical fixation of CO_(2)based on flow chemistry

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Chinese Chemical Letters 2023年第5期34卷 16-24页

作者： Hui Luo Jing Ren Ying Sun Yunlin Liu Feng Zhou Guoyue Shi Jian Zhou School of Chemistry and Molecular Engineering East China Normal UniversityShanghai 200062China School of Chemistry and Chemical Engineering Guangzhou UniversityGuangzhou 510006China Institute of Eco-Chongming Shanghai 202162China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

Carbon dioxide(CO_(2))is an attractive C1 building block in chemical synthesis due to its abundance,availability and ***,the low reactivity and high stability generally limits its transformations under mild conditions to value added *** advances in flow chemistry provide effective means for the chemical transformation of CO_(2),and many new methods and techniques that fully utilized the advantages of continuous flow platforms for the chemical fixation of CO_(2)have been *** view of the rapid development and the urgent need for continuous transformation of CO_(2),herein we wish to present an update of the recent advances in this research area.

关键词： CO_(2)fixation C1 synthon Flow chemistry Cyclic carbonate Carboxylic acid

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Design and analysis of partially decoupled translational parallel mechanisms with single-loop structures

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Frontiers of Mechanical Engineering 2022年第3期17卷 143-157页

作者： Lin WANG Yuefa FANG Dan ZHANG Luquan LI Department of Mechanical Engineering Beijing Jiaotong UniversityBeijing100044China Department of Mechanical Engineering Lassonde School of EngineeringYork UniversityTorontoONM3J 1P3Canada

This study presents a family of novel translational parallel mechanisms(TPMs)with single-loop topological *** proposed mechanism consists of only revolute and prismatic *** novel TPMs are simpler in structure and have fewer joints and components than the well-known Delta *** types of 2-degree of freedom driving systems are applied to different limb structures to avoid the moving actuator that causes the problem of increased moving *** sample TPMs are constructed using the synthesized limbs,and one of them is investigated in terms of kinematic ***,a position analysis is performed and validated through numerical simulation to reveal the characteristics of partially decoupled motion,which improves the controllability of ***,singular configurations are identified,and the resulting singularity curve is ***,the workspace of TPM is analyzed,and the relationship between the singular configurations and the reachable workspace is *** workspace of the 3-CRR(C denotes the cylindrical joint and R denotes the revolute joint)translational mechanism is also presented to prove that the proposed TPM has a fairly large workspace.

关键词： translational parallel mechanism single loop multiple driving system workspace analysis singularity

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Direct C5-Functionalization of Thiazole/Oxazole via C-H Bond Activation and Applications in Structural Modification of Marine Natural Products

Direct C5-Functionalization of Thiazole/Oxazole via C-H Bond...

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中国化学会第十一届全国天然有机化学学术会议

作者： Xiaojiao Wang Yao Li Bowen Lei Yi Zhao Ying Zhu Xia Wu Lifang Ma Ziyuan Li Department of Pharmaceutical and Biological Engineering School of Chemical Engineering Sichuan University

＜正＞Thaizole and oxazole are prevalent scaffolds found in a variety of marine natural products with attractive bioactivities（Fig.1）,many of which do not possess any substitution on C5-positions of their thiazole/oxazole moieties due to limitation of the biosynthesis of these *** the contrary,miscellaneous functional groups on the same positions of artificial molecules provide these compounds with potent and

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Oxygen vacancy promising highly reversible phase transition in layered cathodes for sodium-ion batteries

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Nano research 2021年第11期14卷 4100-4106页

作者： Kezhu Jiang Shaohua Guo Wei Kong Pang Xueping Zhang Tiancheng Fang Shao-fei Wang Fangwei Wang Xiaoyu Zhang Ping He Haoshen Zhou Center of Energy Storage Materials&Technology College of Engineering and Applied SciencesNational Laboratory of Solid State MicrostructuresCollaborative Innovation Center of Advanced MicrostructuresJiangsu Key Laboratory of Artificial Functional MaterialsNanjing UniversityNanjing210093China Institute for Superconducting&Electronic Materials School of MechanicalMaterials and Mechatronics EngineeringUniversity of WollongongWollongongNSW2522Australia China Spallatoin Neutron Source Institute of High Energy PhysicsChinese Academy of SciencesDongguan523808China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing101408China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of SciencesBeijing100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing101408China Songshan Lake Materials Laboratory Dongguan523808China School of materials science and engineering Jiangsu UniversityZhenjiang212013China Energy Technology research Institute National Institute of Advanced Industrial Science and Technology(AIST)Umezono 1-1-1Tsukuba305-8568Japan

Phase transition is common during (de)-intercalating layered sodium oxides, which directly affects the structural stability and electrochemical performance. However, the artificial control of phase transition to achieve advanced sodium-ion batteries is lacking, since the remarkably little is known about the influencing factor relative to the sliding process of transition-metal slabs upon sodium release and uptake of layered oxides. Herein, we for the first time demonstrate the manipulation of oxygen vacancy concentrations in multinary metallic oxides has a significant impact on the reversibility of phase transition, thereby determining the sodium storage performance of cathode materials. Results show that abundant oxygen vacancies intrigue the return of the already slide transition-metal slabs between O_(3) and P_(3) phase transition, in contrast to the few oxygen vacancies and resulted irreversibility. Additionally, the abundant oxygen vacancies enhance the electronic and ionic conductivity of the Na0.9Ni0.3Co0.15Mn0.05Ti0.5O2 electrode, delivering the high initial Coulombic efficiency of 97.1%, large reversible capacity of 112.7 mAh·g−1, superior rate capability upon 100 C and splendid cycling performance over 1,000 cycles. Our findings open up new horizons for artificially manipulating the structural evolution and electrochemical process of layered cathodes, and pave a way in designing advanced sodium-ion batteries.

关键词： sodium-ion battery layered oxide O_(3)phase oxygen vacancy reversible phase transition

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Performance of Recycled Aggregate Concrete-Filled Steel Tubular Members under Various Loadings

Performance of Recycled Aggregate Concrete-Filled Steel Tubu...

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2nd International Conference on Waste Engineering and Management

作者： Youfu YANG(1) (1) State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology P.R.China

＜正＞The technology of re-using waste concrete resources and replacing natural aggregates with recycled aggregate concrete（RAC）,can effectively make use of the waste concrete resources as new building aggregates,save the natural coarse and fine aggregates,and protect the ***-filled steel tube（RACFST） can protect RAC with the confinement of the outer steel tube,and the interaction between the steel tube and core RAC *** is propitious for improving the mechanical performance of *** this paper,the results of experimental and theoretical studies of circular and square RAC-filled steel tubular（RACFST） members under various loadings are presented,and the members are subjected to short-term loadings,long-term sustained loads and cyclic flexural *** numerical methods, including fibre model method（FMM） and finite element method（FEM）,are established to investigate the performance of RACFST members under various *** results in this paper may be taken as reference in related research.

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Advances in Fe(II)/2-ketoglutarate-dependent dioxygenase-mediated C-H bond oxidation for regioselective and stereoselective hydroxyl amino acid synthesis:from structural insights into practical applications

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Systems Microbiology and Biomanufacturing 2021年第3期1卷 275-290页

作者： Xiaoran Jing Huan Liu Yao Nie Yan Xu School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education Jiangnan University1800 Lihu RoadWuxi 214122China State Key Laboratory of Food Science and Technology Jiangnan University1800 Lihu RoadWuxi 214122China Suqian Industrial Technology research Institute of Jiangnan University Suqian 223814China

The asymmetric hydroxylation of inactive carbon atoms in organic compounds remains an important reaction in the industrial synthesis of valuable chiral ***(II)and 2-ketoglutarate-dependent dioxygenases(Fe/2-kg DOs)are the largest known subgroups of mononuclear nonheme-Fe(II)-dependent oxygenases,catalyzing various oxidation reactions of C-H *** developments in Fe/2-kg DO-related researches have coupled concepts from bioinformatics,synthetic biology,and computational biology to establish effective biotransformation *** most well-studied and characterized activ-ity of the Fe/2-kg DOs is substrate hydroxylation,with regard to which mechanistic studies involving the Fe center assist in engineering the protein frameworks of these enzymes to obtain the desired catalytic *** acids are typical substrates of Fe/2-kg DOs and are usually converted into hydroxyl amino acids,which are widely used as intermediates in pharmaceutical and fine chemical ***,we have reviewed prior structural and mechanistic studies on Fe/2-kg DOs,as well as studies on the Fe/2-kg DO-mediated selective C-H oxidation process for selective hydroxyl amino acid synthesis,which will further our journey along the promising path of building complexity via C-H bond ***,new bioinformatics techniques should be adopted with structure-based protein rational design to mine sequence databases and shrink mutant libraries to produce a diverse panel of functional Fe/2-kg DOs capable of catalyzing targeted reactions.

关键词： Fe(II)and 2-ketoglutarate dependent dioxygenases Hydroxylation Hydroxyl amino acids Mechanistic studies Biotransformation

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