检索结果-南通市图书馆

Heteroepitaxial growth of Au@Pd core–shell nanocrystals with intrinsic chiral surfaces for enantiomeric recognition

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第1期43卷 225-235页

作者： feng-Xia Wu feng-Hua Li Xia-Li Lv Qi-Xian Zhang Guo-Bao xu Wen-Xin niu State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Shaoxing Institute of Technology Shanghai UniversityShaoxing 312000China University of Science and Technology of China Hefei 230026China School of Materials Science and Engineering Shanghai UniversityShanghai 200436China Zhejiang Institute of Advanced Materials Shanghai UniversityJiashan 314113China University of Chinese Academy of Sciences Beijing 100039China

Noble metal surfaces with intrinsic chirality serve as an ideal candidate for investigating enantioselective chemistry due to their superior chemical durability and high catalytic ***,significant advance has been made in synthesizing metal nanocrystals with intrinsic ***,the majority reports are limited to ***,through a heteroepitaxial growth strategy,the synthesis of metal nanocrystals with intrinsic chirality to palladium was extended for the first time and their application in enantioselective recognition was *** heteroepitaxial growth strategy allows for transferring the chirality of homochiral Au nanocrystals to Au@Pd core–shell *** employing the chiral Au@Pd nanocrystals as enantiomeric recognizing elements,a series of electrochemical sensors for chiral discrimination were *** optimal conditions,the peak potential between D-dihydroxyphenylalanine(D-DOPA)and L-dihydroxyphenylalanine(L-DOPA)is about 80 m V,and the peak current of D-DOPA is 2 times as much as that of L-DOPA,which enables the determination of the enantiomeric excess(EE,%)of ***,this report not only introduces a heteroepitaxial growth strategy to synthesize metal nanocrystals with intrinsic chirality,but also demonstrates the superior capability of integrating intrinsic chirality and catalytic properties into metal nanocrystals for chiral recognition.

关键词： Core–shell nanostructures Chirality transfer Electrochemical sensors Chiral recognition Chiroplasmonics

Jackson-type inequalities on high-dimensional spheres

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2024年第11期67卷 2571-2586页

作者： Yeli niu feng Dai Department of Mathematics Shanghai Normal University Department of Mathematical and Statistical Sciences University of Alberta

We study Jackson's inequality on high-dimensional spheres with respect to the modulus of smoothness defined via the rotation *** obtain a version of Jackson's inequality with a dimensionfree constant,extending Newman and Shapiro's well-known results in 1964 from the case of r = 1 and p = ∞ to more general *** results partially overcome the curse of *** also establish similar results on the equivalence of the K-functional and modulus of smoothness.

关键词： modulus of smoothness $K$-functional Jackson's inequality high-dimensional approximation

Design and Verification of Parallel Hip Exoskeleton Considering Output Torque Anisotropy

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2024年第3期21卷 1305-1320页

作者： Jilong xu Yunzhan niu Fucai Liu Engineering Research Center of the Ministry of Education for Intelligent Control System and Intelligent Equipment Yanshan UniversityQinhuangdao066004China Key Laboratory of Industrial Computer Control Engineering of Heibei Province Yanshan UniversityQinhuangdao066004China College of Mechanical Engineering Yanshan UniversityQinhuangdao066004China

In rehabilitation training,it is crucial to consider the compatibility between exoskeletons and human legs in ***,most exoskeletons today adopt an anthropomorphic serial structure,which results in rotational centers that are not precisely aligned with the center of the hip *** address this issue,we introduce a novel exoskeleton called the Parallel Hip Exoskeleton(PH-Exo)in this ***-Exo is meticulously designed based on the anisotropic law of output *** the friction of the drive components,a dynamic model of the human-machine complex is *** analysis demonstrates that PH-Exo not only exhibits outstanding torque performance but also achieves high controllability in both flexion/extension and adduction/abduction ***,a robust controller is designed to address model uncertainty,friction,and external *** experiments indicate that under the control of the robust controller,each motor achieves excellent tracking performance.

关键词： Hip exoskeleton Parallel mechanism Misalignment Anisotropy Output torque

Vascularization ability of glioma stem cells in different three-dimensional microenvironments

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Regenerative Biomaterials 2024年第1期3卷 34-43页

作者： xuanzhi Wang Tao xu Chaoshi niu Department of Neurosurgery The First Affliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiAnhui230036China Department of Neurosurgery Sichuan Provincial People's HospitalUniversity of Electronic Science and Technology of ChinaChengdu 610072People's Republic of China Center for Bio-intelligent Manufacturing and Living Matter Bioprinting Research Institute of Tsinghua University in ShenzhenTsinghua UniversityShenzhen 518057People's Republicof China

Glioblastoma(GBM)is among the most common and aggressive adult central nervous system *** prominent charac-teristic of GBM is the presence of abnormal microvessels.A significant correlation between angiogenesis and prognosis has been *** reconstructing this neovascula-rization and tumor microenvironment through personalized in vitro disease models presents a significant ***,it is crucial to develop new anti-angiogenic therapies for *** this study,3D bioprinted glioma stem cell(GSC)-laden hydrogel scaffolds,hybrid Gsc hydrogels and ceil-free hydrogel scaffolds were manufactured to investigate the vas-cularization ability of GsCs in varying 3D microenvironments.

关键词： 3D bioprinting xenograft tumors GSC-laden hydrogel scaffold glioblastoma angiogenesis

Precise phase adjustment and antibacterial property of copper sulfide particles in confined mesoporous silica nanoreactor

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第2期85卷 113-121页

作者： Shiyu xu Jinyong Wu Zhongzhen Ren Dechao niu Low Dimensional Materials Chemistry Laboratory Key Laboratory for Ultrafine Materials of Ministry of EducationFrontier Science Center of the Materials Biology and Dynamic ChemistryShanghai Engineering Research Center of Hierarchical NanomaterialsSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai200237China

Bacteria-caused wound infection greatly threatens human health,thus developing an efficient and safe antibacterial agent without drug resistance is still a great ***,a confined vulcanization strategy is proposed to construct copper sulfides-loaded dual-mesoporous silica nanospheres(Cux-Sy@DMSNs)with various crystal phases for reactive oxygen species(ROS)-mediated and photothermal antibacterial *** the pore confinement of DMSNs,the crystal phases of copper sulfides including CuS,Cu_(9)S_(5)and Cui.96S can be easily controlled by changing the vulcanization *** relationships between the crystal phases and photothermal properties as well as peroxidase-like activity of copper sulfides were systematically *** show that the obtained CuS@DMSNs exhibited higher photothermal ability with remarkable photothermal conversion efficiency of 36.86%in the second near-infrared region(NIR-II)and better peroxidase-like activity,compared to those of Cu_(9)S_(5)@DMSNs and Cu_(1.96)S@*** a result,the in vitro experiments showed the good antibacterial effect against both gram-negative *** and gram-positive *** under 1064 nm laser irradiation and the presence of H_(2)O_(2).Besides,the CCK-8 assay indicated that CuS@p-DMSNs have minimal cytotoxicity against normal human umbilical vein endothelial cells at the ranged ***,the resultant CuS@p-DMSNs could act as a promising antibacterial agent for deep wound bacterial infection treatment.

关键词： Copper sulfides Mesoporous silica Photothermal Reactive oxygen species Antibacterial agent

An active high-static-low-dynamic-stiffness vibration isolator with adjustable buckling beams:theory and experiment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 425-440页

作者： Kefan xu Muqing niu Yewei ZHANG Liqun CHEN School of Science Harbin Institute of TechnologyShenzhen 518055Guangdong ProvinceChina College of Aerospace Engineering Shenyang Aerospace UniversityShenyang 110136China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechanoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China Shanghai Institute of Aircraft Mechanics and Control Shanghai 200092China

High-static-low-dynamic-stiffness(HSLDS)vibration isolators with buckling beams have been widely used to isolate external *** active adjustable device composed of proportion integration(PI)active controllers and piezoelectric actuators is proposed for improving the negative stiffness stroke of buckling beams.A nonlinear output frequency response function is used to analyze the effect of the vibration *** prototype of the active HSLDS device is built,and the verification experiment is *** results show that compared with the traditional HSLDS vibration isolator,the active HSLDS device can broaden the isolation frequency bandwidth,and effectively reduce the resonant amplitude by adjusting the active control *** maximum vibration reduction rate of the active HSLDS vibration isolator can attain 89.9%,and the resonant frequency can be reduced from 31.08 Hz to 13.28 ***,this paper devotes to providing a new design scheme for enhanced HSLDS vibration isolators.

关键词： active control high-static-low-dynamic-stiffness(HSLDS) vibration isola-tor dynamic analysis

Enhanced corrosion resistance of epoxy resin coating via addition of CeO_(2) and benzotriazole

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第3期67卷 89-96页

作者： xu Han Ruijie Guo Baolong niu Hong Yan College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China

The use of fillers to enhance the corrosion protection of epoxy resins has been widely *** this work,cerium dioxide(CeO_(2))and benzotriazole(BTA)were introduced into an epoxy resin to enhance the corrosion resistance of Q235 carbon *** electron microscopy results indicated that the CeO_(2) grains were rod-like and ellipsoidal in shape,and the distribution pattern of BTA was analyzed by energy dispersive *** dynamic potential polarization curve proved the excellent corrosion resistance of the composite epoxy resin with CeO_(2) and BTA co-addition,and electrochemical impedance spectroscopy test analysis indicated the significantly enhanced long-term corrosion protection performance of the composite *** the optimal protective performance was provided by the coating containing 0.3%(mass)CeO_(2) and 20%(mass)BTA,which was attributed to the barrier performance of CeO_(2) particles and the chemical barrier effect of *** formation of corrosion products was analyzed using X-ray *** addition,the corrosion resistance mechanism of the coating was also discussed in detail.

关键词： Benzotriazole Cerium dioxide Corrosion resistance Carbon steel Epoxy resin coating Preparation

Nonlinear constitutive models of rock structural plane and their applications

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 790-806页

作者： Wenlin feng Shuangjian niu Chunsheng Qiao Dujian Zou School of Civil and Environmental Engineering Harbin Institute of TechnologyShenzhenChina Shenzhen Municipal Engineering Corporation Shenzhen518000China School of Civil Engineering Beijing Jiaotong UniversityBeijing100044China

Structural planes play an important role in controlling the stability of rock engineering,and the influence of structural planes should be considered in the design and construction process of rock *** this paper,mechanical properties,constitutive theory,and numerical application of structural plane are studied by a combination method of laboratory tests,theoretical derivation,and program *** test results reveal the change laws of various mechanical parameters under different roughness and normal *** the pre-peak stage,a non-stationary model of shear stiffness is established,and threedimensional empirical prediction models for initial shear stiffness and residual stage roughness are *** nonlinear constitutive models are established based on elasto-plastic mechanics,and the algorithms of the models are developed based on the return mapping *** to a large number of statistical analysis results,empirical prediction models are proposed for model parameters expressed by structural plane characteristic ***,the discrete element method(DEM)is chosen to embed the constitutive models for practical *** running programs of the constitutive models have been compiled into the discrete element model *** comparison results between the proposed model and the Mohr-Coulomb slip model show that the proposed model can better describe nonlinear changes at different stages,and the predicted shear strength,peak strain and shear stiffness are closer to the test *** research results of the paper are conducive to the accurate evaluation of structural plane in rock engineering.

关键词： Structural plane Engineering stability Roughness Normal stress Elasto-plastic constitutive model Discrete element method

Effects of surface energy and substrate on modulus determination of biological films by conical indentation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第6期67卷 1757-1764页

作者： DING Yue LI Cheng-Ya niu XinRui WANG Gang-feng Department of Engineering Mechanics SVLXi’an Jiaotong UniversityXi’an710049China Department of Mechanical Engineering City University of Hong KongHong Kong SAR999077China

Micro-/nano-indentation has become prevalent in evaluating the mechanical characteristics of biological samples,such as cells and ***,the existing contact models describing conical indentation ignore the joint effects of surface energy and substrate,and consequently cannot accurately extract the Young's modulus of biological samples deposited on *** finite element methods,we examine the conical indentation of biological films on substrates while taking surface energy into *** on the dimensional analysis,the explicit relationship between load and indentation depth is achieved for films with their moduli varying from 0.001 to 100 times that of the *** the classical Sneddon's model was employed to analyze the load-depth data,the measured modulus could reach 18 times the real modulus for films on harder substrates,but only 4%of the real modulus for films on softer ***,in micro-/nano-indentations,neglecting the contribution of surface energy would result in an overestimation of the Young's modulus of films depending on the contact *** analytical expression provided here can be utilized to precisely deduce the mechanical characteristics of biological films deposited on substrate from the load and indentation depth data of a conical indentation.

关键词： biological film surface effect substrate effect indentation