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Dendrimer-induced synthesis of porous organosilica capsules for enzyme encapsulation

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Frontiers of Chemical Science and Engineering 2024年第4期18卷 41-48页

作者： Ziyi Chu Boyu zhang Zhenhua Wu jiaxu zhang Yiran Cheng Xueying Wang Jiafu Shi Zhongyi Jiang School of Environmental Science&Engineering Tianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072China State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

Organic matter-induced mineralization is a green and versatile method for synthesizing hybrid nanostructured materials,where the material properties are mainly influenced by the species of natural biomolecules,linear synthetic polymer,or small molecules,limiting their diversity.Herein,we adopted dendrimer poly(amidoamine)(PAMAM)as the inducer to synthesize organosilica-PAMAM network(OSPN)capsules for mannose isomerase(MIase)encapsulation based on a hard-templating method.The structure of OSPN capsules can be precisely regulated by adjusting the molecular weight and concentration of PAMAM,thereby demonstrating a substantial impact on the kinetic behavior of the MIase@OSPN system.The MIase@OSPN system was used for catalytic production of mannose from Dfructose.A mannose yield of 22.24% was obtained,which is higher than that of MIase in organosilica network capsules and similar to that of the free enzyme.The overall catalytic efficiency(kcat/Km)of the MIase@OSPN system for the substrate D-fructose was up to 0.556 s^(-1)·mmol^(-1)·L.Meanwhile,the MIase@OSPN system showed excellent stability and recyclability,maintaining more than 50% of the yield even after 12 cycles.

关键词： enzyme immobilization enzyme catalysis organosilica networks capsules sugar biosynthesis

A novel long persistent luminescent material CaGeO3:Tb3+ with photo-stimulation properties

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Journal of Rare Earths 2024年第7期42卷 1233-1239页

作者： Wei Meng Xiaoyan Fu Tongyan Lin Zewen Liu Naihui Chen jiaxu zhang Runyao Liu Rujun Yang Long Chen Hongwu zhang School of Chemistry and Material Sciences Ludong University College of Materials Science and Engineering Xiamen University of Technology College of Materials Xiamen University

A novel green long afterglow material CaGeO3:Tb3+was synthesized by high temperature solid phase method.According to the experimental results,CaGeO3:Tb3+is a green long persistent luminescent（LPL）material with excellent performance.CaGeO3:Tb3+shows LPL emission peak at 442,490.9,548.7,588.5and 623.8 nm,corresponding to5D3to7F4and5D4to7FJ（J=6,5,4,3） transitions of Tb3+,Its CIE coordinates are（0.27,0.50）,indicating that the afterglow emission is close to the light of green region.In addition,after the excitation source is turned off,the afterglow time is longer than 90 min.After an interval of 7 h,the photo-stimulation luminescence（PSL） can be observed by using 980 nm laser cyclic excitation.The thermoluminescence（ThL） results show that there are three types of traps in the material and their depths are 0.666,0.774 and 0.892 eV respectively,which are caused by the doping of Tb3+.All the results show that CaGeO3:Tb3+is an excellent long afterglow luminescent material.

关键词： CaGeO3:Tb3+ Long persistent luminescence Photo-stimulation Rare earths Trap

A Trade-off between Solvation and Collision Activation in Steering Competing E2 and S_(N)2 Dynamics

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Precision Chemistry

Precision Chemistry 2024年第1期2卷 40-48页

作者： Hongyi Wang Xu Liu Siwei Zhao Gang Fu Wenqing Zhen Li Yang jiaxu zhang State Key Laboratory of Urban Water Resource and Environment MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and StorageSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001P.R.China College of Chemistry Liaoning UniversityShenyang 110036P.R.China

The prototypical E2 elimination and SN2 sub-stitution reactions between microsolvated fluoride and ethyl bromide show unexpected dynamic behaviors in mechanistic evolution driven by solvation and collision activation.Considering the steric effects,the gas-phase selectivity favors an E2 pathway barely dependent on collision energies.Remarkably,base solvation steers the reaction in an effective way toward substitution at a near-thermal energy,whereas the governing high-energy events retain elimination.Chemical dynamics simulations reproduce exper-imental findings and uncover a crucial solute-solvent coupling in determining such competing processes.Interestingly,collision activation can tune the underlying atomistic dynamics essentially in the reactant entrance channel and cause a mechanism shift.These features for the ubiquitous competing E2/SN2 dynamics remain quite unknown,providing unique insight into reaction selectivity for complex chemical networks.

关键词： E2/S_(N)2 Competition Atomistic Dynamics Reaction Mechanisms Microsolvation Collision Activation

Unified method for typical gear failure modeling and stiffness calculation based on the matrix equation

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Frontiers of Mechanical Engineering 2024年第3期19卷 93-114页

作者： Fanshan MENG Xin zhang Heng XIA jiaxu WANG School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Mechanical Transmissions for Advanced Equipment Chongqing UniversityChongqing 400044China

The failure types in gear systems vary,with typical ones mainly including pitting,cracking,wear,and broken teeth.Different modeling and stiffness calculation methods have been developed for various gear failure types.A unified method for typical gear failure modeling and stiffness calculation is introduced in this study by considering the deviations in the time-varying meshing stiffness(TVMS)of faulty gears resulting from the use of different methods.Specifically,a gear tooth is discretized into a large number of microelements expressed with a matrix,and unified models of typical gear failures are built by adjusting the values of the matrix microelements.The values and positions of the microelements in the tooth failure model matrix have the same physical meaning as the parameter variables in the potential energy method(PEM),so the matrix-based failure model can be perfectly matched with PEM.Afterward,a unified method for TVMS is established.Modeling of healthy and faulty gears with pitting,wear,crack,and broken tooth is performed with the matrix equation,and the corresponding TVMS values are calculated by incorporating the matrix models with PEM.On the basis of the results,the mechanism of typical fault types that affect TVMS is analyzed,and the conclusions are verified through the finite element method.The developed unified method is a promising technique for studying the dynamic response characteristics of gear systems with different failure types because of its superiority in eliminating stiffness deviations.

关键词： gears matrix equation failure modeling TVMS calculation unified method

Atomically precise metal chalcogenide supertetrahedral clusters:frameworks to molecules,and structure to function

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National Science Review 2022年第1期9卷 128-143页

作者： jiaxu zhang Pingyun Feng Xianhui Bu Tao Wu College of Chemistry Chemical Engineering and Material Science Soochow University Department of Chemistry University of California College of Chemistry and Materials Science Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications Jinan University Department of Chemistry and Biochemistry California State University

Metal chalcogenide supertetrahedral clusters(MCSCs) are of significance for developing crystalline porous framework materials and atomically precise cluster chemistry.Early research interest focused on the synthetic and structural chemistry of MCSC-based porous semiconductor materials with different cluster sizes/compositions and their applications in adsorption-based separation and optoelectronics.More recently,focus has shifted to the cluster chemistry of MCSCs to establish atomically precise structure-composition-property relationships,which are critical for regulating the properties and expanding the applications of MCSCs.Importantly,MCSCs are similar to Ⅱ-Ⅵ or Ⅰ-Ⅲ-Ⅵ semiconductor nanocrystals(also called quantum dots,QDs) but avoid their inherent size polydispersity and structural ambiguity.Thus,discrete MCSCs,especially those that are solution-processable,could provide models for understanding various issues that cannot be easily clarified using QDs.This review covers three decades of efforts on MCSCs,including advancements in MCSC-based open frameworks(reticular chemistry),the precise structure-property relationships of MCSCs(cluster chemistry),and the functionalization and applications of MCSC-based micro crystals.An outlook on remaining problems to be solved and future trends is also presented.

关键词： metal chalcogenide nanocluster open framework semiconductor reticular chemistry atomically precise nanochemistry

Triaxial mechanical properties and precursors of instability damage in rocks with different laminar dip angles

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Journal of Mountain Science 2024年第2期21卷 648-661页

作者： SUN Xiaoming SHI Fukun DING jiaxu TAO Zhigang HE Linsen YANG Liu zhang Yong MIAO Chengyu Inner Mongolia Research Institute China University of Mining and Technology(Beijing)Beijing 100083China State Key Laboratory for Tunnel Engineering China University of Mining and Technology(Beijing)Beijing 100083China

To investigate the mechanical failure characteristics of volcanic breccia with different bedding dip angles in deep layers,triaxial compression experiments were conducted on specimens taken from volcanic rock layers in the Junggar Basin,Xinjiang.By changing the confining pressure,we compared the mechanical properties,acoustic emission characteristics,and fractal features of the acoustic emission sequence for volcanic breccia with different bedding dip angles.The research results indicate that as the bedding dip angle increases,peak strength,internal friction angle,and cohesion exhibit a“U-shaped”variation pattern.The correlation dimension of the acoustic emission amplitude was calculated using the G-P algorithm,revealing that volcanic breccia exhibits fractal characteristics.Furthermore,a positive correlation between the correlation dimension and the bedding dip angle was observed.When the stress of the test specimen reaches 0.8σ_(c),there is a significant decrease in the fractal dimension,serving as a criterion for predicting the failure of the specimen.By analyzing the changes in fractal dimension at different stress levels,the slope of the fractal dimension△D<-0.5 can be used as a precursor to failure for test specimens with a bedding dip angle of 15°≤β≤45°.Similarly,when the bedding dip angle of the specimen is 0°≤β<15°or 45°<β≤90°,△D<0 can be considered as a precursor to specimen failure.This study provides theoretical references for understanding the failure patterns of volcanic rock.

关键词： Volcanic breccia Bedding dip Acoustic emission Fractal dimension Harbinger of destruction

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Slippery Surface with Petal-like Structure for Protecting Al Alloy: Anti-corrosion, Anti-fouling and Anti-icing

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Journal of Bionic Engineering 2022年第1期19卷 83-91页

作者： Junfei Huang Jiajie Kang jiaxu zhang Jinxia Huang Zhiguang Guo School of Engineering and Technology China University of GeosciencesBeijing100083China Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials Hubei UniversityWuhan430062China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China Zhengzhou Institute China University of Geosciences(Beijing)Zhengzhou451283China

The harsh working environment affects the performance and usage life of Al and its alloys,thus limiting their application.In recent years,Slippery Liquid-infused Porous Surface(SLIPS)has attracted much attention due to excellent anti-corrosion,anti-fouling and anti-icing properties.This may be an effective way to improve the properties of Al and its alloys.Here,the SLIPS with petal-like structure was constructed on the Al alloy via simple hydrothermal reaction,Stearic Acid(STA)modification and lubricant injection.A variety of droplets(including oil-in-water emulsions)can slide on the SLIPS at a low angle,even the Sliding Angle(SA)of the water droplet is only 3°.Furthermore,the SLIPS exhibits outstanding mechanical and chemical properties.It can maintain fine oil-locking ability under high shearing force and keep slippery stability after immersion in acid/alkaline solutions.In addition,the SLIPS possesses excellent anti-corrosion,anti-fouling and anti-icing properties,which provides a new way to promote the application of Al and its alloys.Therefore,the SLIPS is expected to be an effective way to improve the properties of Al and its alloys,as well as play a role in anti-fouling and self-cleaning in construction,shipbuilding and automotive manufacturing industries,thereby expanding the practical application of Al and its alloys.

关键词： Slippery surface Al alloy Anti-corrosion Anti-fouling Anti-icing

A spatial attentive and temporal dilated(SATD)GCN for skeleton-based action recognition

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CAAI Transactions on Intelligence Technology 2022年第1期7卷 46-55页

作者： jiaxu zhang Gaoxiang Ye Zhigang Tu Yongtao Qin Qianqing Qin Jinlu zhang Jun Liu State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanChina State Grid Wuhan Power Supply Company WuhanChina Shenzhen Infinova Ltd.Company ShenzhenChina Information Systems Technology and Design Pillar Singapore University of Technology and DesignSingapore

Current studies have shown that the spatial-temporal graph convolutional network(STGCN)is effective for skeleton-based action recognition.However,for the existing STGCN-based methods,their temporal kernel size is usually fixed over all layers,which makes them cannot fully exploit the temporal dependency between discontinuous frames and different sequence lengths.Besides,most of these methods use average pooling to obtain global graph feature from vertex features,resulting in losing much fine-grained information for action classification.To address these issues,in this work,the authors propose a novel spatial attentive and temporal dilated graph convolutional network(SATD-GCN).It contains two important components,that is,a spatial attention pooling module(SAP)and a temporal dilated graph convolution module(TDGC).Specifically,the SAP module can select the human body joints which are beneficial for action recognition by a self-attention mechanism and alleviates the influence of data redundancy and noise.The TDGC module can effectively extract the temporal features at different time scales,which is useful to improve the temporal perception field and enhance the robustness of the model to different motion speed and sequence length.Importantly,both the SAP module and the TDGC module can be easily integrated into the ST-GCN-based models,and significantly improve their performance.Extensive experiments on two large-scale benchmark datasets,that is,NTU-RGB+D and Kinetics-Skeleton,demonstrate that the authors’method achieves the state-of-the-art performance for skeleton-based action recognition.

关键词： classification. skeleton action

Transformation of Undesired Li_(2)CO_(3)into Lithiophilic Layer Via Double Replacement Reaction for Garnet Electrolyte Engineering

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Energy & Environmental Materials 2022年第3期5卷 962-968页

作者： jiaxu zhang Ruohan Yu Jun Li Huiyu Zhai Gangjian Tan Xinfeng Tang State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China International School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

Garnet-type solid-state electrolytes(SSEs)are a remarkable Li-ion electrolyte for the realization of next-generation all-solid-state lithium batteries due to their excellent stability against Li metal as well as high ionic conductivities at room temperature.However,garnet electrolytes always contain undesired and hardly removable Li_(2)CO_(3) contaminations that have persistently large resistance and unstable interface contact with Li metal.This is a critical bottleneck for the practical application of garnet electrolytes.Here,we design a novel strategy to completely root out Li_(2)CO_(3) both inside and on the surface of garnet.This is achieved by a so-called double replacement reaction between Li_(2)CO_(3) and SiO_(2) during one-step hot press process for garnet electrolyte densification.It leads to in-situ transformation of LixSiOy(LSO)mostly locating around the grain boundaries of garnet.Due to the higher ion conductivity and better electrochemistry stability of LSO than Li_(2)CO_(3),the modified garnet electrolyte shows much improved electrochemical performance.Moreover,the wettability between modified garnet electrolyte and lithium metals was significantly enhanced in the absence of surface Li_(2)CO_(3).As a proof of concept,an assembled Li symmetric cell with modified garnet electrolyte displays a high critical current density(CCD)of 0.7 mA cm^(-2)and a low interfacial impedance(5Ωcm^(2))at 25℃.These results indicate that the upcycling of Li_(2)CO_(3)is a promising strategy to well-address the degradation and interfacial issue associated with garnet electrolytes.

关键词： double replacement reaction garnet electrolytes lithiophilic layer solid-state lithium batteries

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