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Practical Structural Design Approach of Multiconfiguration Planar Single‑Loop Metamorphic Mechanism with a Single Actuator

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Chinese Journal of Mechanical Engineering 2020年第5期33卷 19-33页

作者： Qiang Yang Guangbo Hao shujun li Hongguang Wang Haiyang li College of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China Department of Electrical and Electronic Engineering University College CorkCork T12 K8AFIreland State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016China

As a type of multiconfiguration mechanism that can operate in an under-actuated state,metamorphic mechanisms were proposed more than two decades ago and attracted significant *** on structural synthesis of metamorphic mechanisms tend to focus more on metamorphic techniques and the structural synthesis of source mechanisms for metamorphic *** designing different constraint architectures of metamorphic joints,multistructures can be obtained from the same source metamorphic *** determine the constraint architectures of metamorphic joints and their different assembly combinations,a kinematic status matrix and a corresponding constraint status matrix are constructed based on the metamorphic cyclogram of a source *** to the equivalent resistance gradient model and the constraint status matrix,an equivalent resistance matrix for the metamorphic joints is proposed.A structural synthesis matrix of the metamorphic mechanism is then obtained from the equivalent resistance matrix by deducing the constraint form vectors of the metamorphic ***,a kinematic diagram synthesis of the source metamorphic mechanism of a planar single-loop metamorphic mechanism is proposed,which is based on only the 14 one-or zero-degrees-of-freedom linkage *** entire structural design method of a metamorphic mechanism is based on the structural synthesis matrix and is presented as a systematic ***,the proposed structural design approach is illustrated by two examples to verify its feasibility and *** study provides an effective method for designing a practical multi-mobility and multiconfiguration planar single-loop metamorphic mechanism with a single actuator.

关键词： Metamorphic mechanism Structural design Form of metamorphic joints Multiconfiguration Equivalent resistance Single actuator

Longitudinal Compression Behavior of Functionally Graded Ti–6Al–4V Meshes

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Journal of Materials Science & Technology 2016年第11期32卷 1098-1104页

作者： Shangzhou Zhang Cong li Wentao Hou Shuo Zhao shujun li School of Environmental and Materials Engineering Yantai University Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences

The compressive deformation behavior in the longitudinal direction of graded Ti–6Al–4V meshes fabricated by electron beam melting was investigated using experiments and finite element methods（FEM）.The results indicate that the overall strain along the longitudinal direction is the sum of the net strain carried by each uniform mesh constituent and the deformation behavior fits the Reuss model well. The layer thickness and the sectional area have no effect on the elastic modulus, whereas the strength increases with the sectional area due to the edge effect of each uniform mesh constituent. By optimizing3 D graded/gradient design, meshes with balanced superior properties, such as high strength, energy absorption and low elastic modulus, can be fabricated by electron beam melting.

关键词： Graded Ti–6Al–4V meshes Electron beam melting Reuss model Compressive deformation Edge effect

Effect of Elastic Modulus on Biomechanical Properties of Lumbar Interbody Fusion Cage

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Journal of Materials Science & Technology 2009年第3期25卷 325-328页

作者： Yue Zhu Fusheng li shujun li Yulin Hao Rui Yang Department of Orthopaedics the First Affiliated Hospital of China Medical University Shenyang 110001 China Department of Bone Tumor The Peoplers Hospital of Liaoning Province Shenyang 110016 China Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

This work focuses on the influence of elastic modulus on biomechanical properties of lumbar interbody fusion cages by selecting two titanium alloys with different elastic modulus. They were made by a new β type alloy with chemical composition of Ti-24Nb-4Zr-7.6Sn having low Young＇s modulus -50 GPa and by a conventional biomedical alloy Ti-6Al-4V having Young＇s modulus -110 GPa. The results showed that the designed cages with low modulus （LMC） and high modulus （HMC） can keep identical compression load -9.8 kN and endure fatigue cycles higher than 5× 10^6 without functional or mechanical failure under 2.0 kN axial compression. The anti-subsidence ability of both group cages were examined by axial compression of thoracic spine specimens （T9-T10） dissected freshly from the calf with averaged age of 6 months. The results showed that the LMC has better anti-subsidence ability than the HMC （p〈0.05）. The above results suggest that the cage with low elastic modulus has great potential for clinical applications.

关键词： Titanium alloy Lumbar Interbody fusion cage Biomechanics

Polyoxymethylene dimethyl ethers synthesis from methanol and formaldehyde solution over one-pot synthesized spherical mesoporous sulfated zirconia

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Chinese Journal of Chemical Engineering 2022年第6期35卷 161-172页

作者： Xiangjun li shujun li Xiaoping Wang Muhammad Asif Nawaz Dianhua liu State Key Lab of Chemical Engineering East China University of Science and TechnologyShanghai 200237China

The synthesis of polyoxymethylene dimethyl ethers as an ideal diesel fuel additive is the current hot topic of modern petrochemical industry for their expedient properties in mitigating air pollutants emission during *** this work,a series of spherical sulfated zirconia catalysts were prepared by a one-pot hydrothermal method assisted with surfactant cetyltrimethylammonium bromide(CTAB).The prepared sulfated zirconia catalysts were used to catalyze PODEn synthesis from methanol and formaldehyde *** characterization(XRD,BET,SEM,TGA,NH_(3)-TPD,FTIR,and Py-IR)were employed to elaborate the structure–activity relationship of the studied catalytic *** results demonstrated that S/Zr molar ratio in precursor solution played an effective role on catalyst morphology and acidic properties,where the weak Brønsted acid sites and strong Lewis acid sites were favorable to the conversion of methanol and formation of long-chain PODEn,*** reaction parameters such as catalyst amount,molar ratio of FA/MeOH,reaction time,temperature and pressure were *** speculated reaction pathway for PODEn synthesis was proposed based on the synergy of Brønsted and Lewis acid sites,which suggested that Brønsted and Lewis acid sites might be advantageous to the activation of polyoxymethylene hemiformals[CH_(3)(OCH_(2))_(n)OH]and methylene glycol(HOCH_(2)OH),respectively.

关键词： Polyoxymethylene dimethyl ethers Spherical sulfated zirconia Methanol Formaldehyde Reaction pathway Synergistic effect

Transition metal-mediated catalytic properties of gold nanoclusters in aerobic alcohol oxidation

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Nano Research 2018年第4期11卷 2139-2148页

作者： Chaolei Zhang Yongdong Chen Hong Wang Zhimin li Kai Zheng shujun li Gao li College of Chemistry and Chemical Engineering Southwest Petroleum University Chengdu 610500 China Gold Catalysis Research Center State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China

Heteroatom dopants can greatly modify the electronic and physical properties and catalytic performance of gold nanoclusters. In this study, we investigate the catalytic activity of [Au25-x（PET）18-xM]NH3 （PET = 2-phenylethanethiolate, and M = Cu, Co, Ni, and Zn） nanoclusters in aerobic alcohol oxidation. The [Au25-xPET）18-xM]NH3 nanoclusters are thoroughly characterized by matrix assisted laser desorption ionization （MALDI） mass spectrometry, X-ray photoelectron spectroscopy （XPS）, Fourier transform infrared spectroscopy （FT-IR）, and inductively coupled plasma-mass spectrometry （ICP-MS）. The XPS analyses suggest that the transition metals strongly interact with the gold atoms of the nanoclusters. The CeO2-supported nanoclusters show catalytic activity, based on the conversion of benzyl alcohol, in the order, [Au25-x（PET）18-xNi] 〉 [Au25-x（PET）18-xCu] 〉 [Au25-x（PET）18-xZn] 〉 [Au25-x（PET）18-xCo]. Regarding product selectivity, the [Au25-xPET）18-xZn] and [Au25-x（PET）18-xCo] catalysts preferably yield benzaldehyde, [Au25-x（PET）18-xCu] yields benzaldehyde and benzyl acid, and [Au25-x（PET）18-xNi] yields benzyl acid. The exposed metal atoms are considered as the catalytic active sites. Also, the catalytic performance （including activity and selectivity） of the [Au25-x（PET）18-xM] catalysts is greatly turned and mediated by the transition metal type.

关键词： gold nanoclusters heteroatom dopant transition metal oxidation alcohol

Fibroblast Adhesion and Proliferation on a New β Type Ti-39Nb-13Ta-4.6Zr Alloy for Biomedical Application

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Journal of Materials Science & Technology 2006年第2期22卷 205-210页

作者： Yongkang ZHAO Yang YAO Weixian liU Caiyun ZHENG shujun li The Second Affiliated Hospital China Medical University Shenyang 110004 China Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

Cell attachment and spreading on Ti-based alloy surfaces is a major parameter in implant technology. Ti-39Nb-13Ta-4.6Zr alloy is a new β type Ti alloy developed for biomedical application. This alloy has low modulus and high strength, which indicates that it can be used for medical purposes such as surgical implants. To evaluate the biocompatibility and effects of the surface morphology of Ti-39Nb-13Ta-4.6Zr on the cellular behaviour, the adhesion and proliferation of rat gingival fibroblasts were studied with substrates having different surface roughness and the results were also compared with commercial pure titanium and Ti-6Al-4V. The results indicate that fibroblast shows similar adhesion and proliferation on the smooth surfaces of commercial pure titanium （Cp Ti）, Ti-39Nb-13Ta-4.6Zr, and Ti-6Al-4V, suggesting that Ti-39Nb-13Ta-4.6Zr has similar biocompatibility to Cp Ti and Ti-6Al-4V. The fibroblast adhesion and spreading was lower on rough surfaces of Cp Ti, Ti-39Nb-13Ta-4.6Zr and Ti-6Al-4V than on smooth ones. Surface roughness appeared to be a dominant factor that determines the fibroblast adhesion and proliferation.

关键词： Biomaterials Titanium alloys Fibroblast Adhesion Proliferation Surface roughness

Finite element analysis of temperature and residual stress profiles of porous cubic Ti-6Al-4V titanium alloy by electron beam melting

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Journal of Materials Science & Technology 2020年第9期44卷 191-200页

作者： Xiaochun He Yang li Yongjie Bi Xiaomei liu Bing Zhou Shangzhou Zhang shujun li School of Nuclear Equipment and Nuclear Engineering Yantai UniversityYantai 264005China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China

The temperature and stress profiles of porous cubic Ti-6Al-4V titanium alloy grids by additive manufacturing via electron beam melting(EBM)based on finite element(FE)method were ***-dimensional FE models were developed to simulate the single-layer and five-layer girds under annular and lateral *** results showed that the molten pool temperature in five-layer girds was higher than that in single-layer grids owing to the larger mass and higher heat *** energies accumulated by the longer scanning time for annular path than lateral path led to the higher temperature and steeper temperature *** thermal stress drastically fluctuated during EBM process and the residual stress decreased with the increase of powder layer where the largest stress appeared at the first layer along the build *** stress under lateral scanning was slightly larger but relatively more homogeneous distribution than those under annular *** stress distribution showed anisotropy and the maximum Von Mises stress occurred around the central *** stress profiles were explained by the temperature fields and grids structure.

关键词： Electron beam melting Ti-6Al-4V titanium alloy Porous cubic grids Finite element analysis Temperature field Stress field

A robust adversarial attack against speech recognition with UAP

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High-Confidence Computing 2023年第1期3卷 18-22页

作者： Ziheng Qin Xianglong Zhang shujun li Shandong University School of Computer Science and TechnologyQingdao 266237China Yancheng Teachers University School of Information EngineeringYancheng 224002China

Speech recognition(SR)systems based on deep neural networks are increasingly widespread in smart ***,they are vulnerable to human-imperceptible adversarial attacks,which cause the SR to generate incorrect or targeted adversarial ***,audio adversarial attacks are particularly susceptible to various factors,e.g.,ambient noise,after applying them to a real-world *** circumvent this issue,we develop a universal adversarial perturbation(UAP)generation method to construct robust real-world UAP by integrating ambient noise into the generation *** proposed UAP can work well in the case of input-agnostic and independent *** validate the effectiveness of our method on two different SRs in different real-world scenarios and parameters,the results demonstrate that our method yields state-of-the-art performance,*** any audio waveform,the word error rate can be up to 80%.Extensive experiments investigate the impact of different parameters(e.g,signal-to-noise ratio,distance,and attack angle)on the attack success rate.

关键词： Machine learning security Audio adversarial attack

Low-cost surface modification of a biomedical Zr-2.5Nb alloy fabricated by electron beam melting

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Journal of Materials Science & Technology 2023年第12期143卷 178-188页

作者： Caixu Wang Xiaoli Zhao shujun li Lu liu Deliang Zhang Mitsuo Niinomi School of Materials Science and Engineering Northeastern UniversityShenyang 110819China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Key Laboratory of Data Analytics and Optimization for Smart Industry(Ministry of Education) Northeastern UniversityShenyang 110819China Tianjin Key Laboratory of Bone Implants Interface Functionalization and Personalization Tianjin 300190China Institute for Materials Research Tohoku UniversitySendaiMiyagi 9808577Japan Division of Materials and Manufacturing Science Graduate School of EngineeringOsaka UniversityOsaka 565-0871Japan Department of Materials Science and Engineering Graduate School of Science and TechnologyMeijo UniversityNagoya 468-8502Japan Faculty of Chemistry Materials and BioengineeringKansai UniversityOsaka 564-860Japan

The Zr-2.5Nb alloy with a fine microstructure consisting ofαlaths was successfully prepared by electron beam melting(EBM).The thermal oxidation behaviors and kinetics of the as-built,and the EBM-built and hot isostatically pressed(HIPed)Zr-2.5Nb materials in a temperature range of 450-600°C were in-vestigated and compared with those of the alloy prepared by conventional casting and *** was found that the oxidation kinetics of the as-built and the forged materials followed the parabolic rate law during isothermal oxidation at 550°C,but the HIPed materials exhibited a parabolic-to-linear kinetic transition,suggesting that the larger grain sizes enhanced the *** oxide layers of all materials were composed of a large fraction of monoclinic zirconia phase(m-ZrO_(2))and a small fraction of tetrago-nal zirconia phase(t-ZrO_(2)),and transformed from t-ZrO_(2)to m-ZrO_(2)with increasing oxidation *** surface hardness of the as-built,the forged and the HIPed materials increased from 215,204,and 188 HV before oxidation to 902,1070,and 1137 HV after oxidation,*** cross-sections of the materi-als showed the presence of micropores and microcracks inside the oxide layers with thicknesses ranging from 4 to 8μ*** the oxidation temperature of 600°C and oxidation time duration of 3 h,a dense black m-ZrO_(2)oxide layer with smooth surface and 902 HV hardness was obtained on the EBM as-built Zr-2.5Nb materials.

关键词： Zr-2.5Nb alloy Electron beam melting Thermal oxidation Oxidation behaviors and kinetics Grain size