检索结果-南通市图书馆

Probabilistic-Ellipsoid Hybrid Reliability Multi-Material Topology Optimization Method Based on Stress Constraint

Computer Modeling in engineering & Sciences 2024年第7期140卷 757-792页

作者： Zibin Mao Qinghai Zhao Liang Zhang College of mechanical and electrical engineering Qingdao UniversityQingdao266071China National engineering Research center for Intelligent electrical Vehicle Power System Qingdao UniversityQingdao266071China

This paper proposes a multi-material topology optimization method based on the hybrid reliability of the probability-ellipsoid model with stress constraint for the stochastic uncertainty and epistemic uncertainty of mechanical loads in optimization design.The probabilistic model is combined with the ellipsoidal model to describe the uncertainty of mechanical loads.The topology optimization formula is combined with the ordered solid isotropic material with penalization(ordered-SIMP)multi-material interpolation model.The stresses of all elements are integrated into a global stress measurement that approximates the maximum stress using the normalized p-norm function.Furthermore,the sequential optimization and reliability assessment(SORA)is applied to transform the original uncertainty optimization problem into an equivalent deterministic topology optimization(DTO)problem.Stochastic response surface and sparse grid technique are combined with SORA to get accurate information on the most probable failure point(MPP).In each cycle,the equivalent topology optimization formula is updated according to the MPP information obtained in the previous cycle.The adjoint variable method is used for deriving the sensitivity of the stress constraint and the moving asymptote method(MMA)is used to update design variables.Finally,the validity and feasibility of the method are verified by the numerical example of L-shape beam design,T-shape structure design,steering knuckle,and 3D T-shaped beam.

关键词： Stress constraint probabilistic-ellipsoid hybrid topology optimization reliability analysis multi-material design

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Machine-learned wearable sensors for real-time hand-motion recognition: toward practical applications

引用

National Science Review 2024年第2期11卷 231-263页

作者： Kyung Rok Pyun Kangkyu Kwon Myung Jin Yoo Kyun Kyu Kim Dohyeon Gong Woon-Hong Yeo Seungyong Han Seung Hwan Ko Department of mechanical engineering Seoul National University IEN center for Human-Centric Interfaces and engineering Institute for Electronics and NanotechnologyGeorgia Institute of Technology School of electrical and Computer engineering Georgia Institute of Technology Department of Chemical engineering Stanford University Department of mechanical engineering Ajou University George W.Woodruff School of mechanical engineering Georgia Institute of Technology Institute of Advanced Machinery and Design(SNU-IAMD) Seoul National University

Soft electromechanical sensors have led to a new paradigm of electronic devices for novel motion-based wearable applications in our daily lives. However, the vast amount of random and unidentified signals generated by complex body motions has hindered the precise recognition and practical application of this technology. Recent advancements in artificial-intelligence technology have enabled significant strides in extracting features from massive and intricate data sets, thereby presenting a breakthrough in utilizing wearable sensors for practical applications. Beyond traditional machine-learning techniques for classifying simple gestures, advanced machine-learning algorithms have been developed to handle more complex and nuanced motion-based tasks with restricted training data sets. Machine-learning techniques have improved the ability to perceive, and thus machine-learned wearable soft sensors have enabled accurate and rapid human-gesture recognition, providing real-time feedback to users. This forms a crucial component of future wearable electronics, contributing to a robust human–machine interface. In this review, we provide a comprehensive summary covering materials, structures and machine-learning algorithms for hand-gesture recognition and possible practical applications through machine-learned wearable electromechanical sensors.

关键词： wearable sensor soft electronics artificial intelligence machine learning human–machine interfaces gesture recognition

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Strengthening effect of prefabrication(10-12) tensile twinning on AZ80+0.4%Ce magnesium alloy and inhibition mechanism of discontinuous precipitation

引用

Journal of Magnesium and Alloys 2024年第5期12卷 1918-1930页

作者： Zhen Wang Xi Zhao Zhimin Zhang Yaojin Wu Kai Chen Xianwei Ren Dengkui Wang Wei Wang School of mechanical and electrical engineering North University of China engineering Technology Research center for Integrated Precision Forming of Shanxi Province North University of China

This paper provided an effective method to further improve the mechanical properties of the AZ80+0.4%Ce magnesium alloy wheel spoke. The effect of high strength and ductility was obtained with a yield strength of 295.36 MPa, an elongation of 10%, by the combination of pre-deformation(7% deformation) and two-stage aging treatment(120 ℃/9 h + 175 ℃/24 h). The evolution of the microstructure and properties of the alloy was explored under the coupling conditions of different pre-deformation degrees and multi-stage aging. The results show that, pre-deformation introduced a large number of(■) tensile twinning and dislocations, which greatly promoted the probability of continuous precipitates(CPs) appearing. On the contrary, the discontinuous precipitates(DPs) were limited by the vertical and horizontal twin structure. As a result, the pre-nucleation method of two-stage aging increased the proportion of CPs by 34%-38%. Owing to the DPs was effectively suppressed, the alloy's yield strength has been greatly improved. Besides, under multi-stage aging, the twin boundaries induce protruding nucleation to form static recrystallization by hindering the migration of dislocations, and the matrix swallows the twins, then the texture gradually tilts from the two poles to the basal plane. As an important supplement, the grain refinement and oblique texture promoted the improvement of the yield strength of the component.

关键词： Magnesium alloy Pre-deformed Two-stage aging Tensile twinning Continuous precipitates Texture

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Flat jet electrochemical milling of TC4 alloy with tailoring backward parallel flow

引用

Chinese Journal of Aeronautics 2024年第4期37卷 574-592页

作者： Huanghai KONG Ningsong QU College of mechanical and electrical engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

In flat jet electrochemical milling, the electrolyte forms a backward parallel flow after impacting the workpiece, resulting in a weak current density distribution on the workpiece. Poor surface quality usually occurs on the machined titanium alloy surface because it inevitably suffers from the weak current density. In this study, a method of flat jet electrochemical milling with tailoring the backward parallel flow was proposed to eliminate the negative effects caused by the weak current density. Multiphysics simulations are carried out to comprehend the mechanism of flat jetEC milling with tailoring backward parallel flow and better construct the novel tool electrode.Experiments on flat jet electrochemical milling of TC4 alloy with and without tailoring backward parallel flow are conducted. The results reveal that, compared with flat jet electrochemical milling without tailoring backward parallel flow, the recommended tool reduces the surface roughness by86% to 93%, and improves the material removal rate by 93% to 163% with different feed rates.Additionally, the recommended tool is more conducive to maintaining the inherent hardness of the material. Finally, a surface with low Sa of 0.37 μm is obtained.

关键词： Flat jet electrochemical milling TC4 alloy Surface roughness Micro-hardness Material removal rate

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A direct electrochemical biosensor for rapid glucose detection based on nitrogen-doped carbon nanocages

引用

Rare Metals 2024年第5期43卷 2184-2192页

作者： Lan-Lan Li Yu Zhao Li-Jia Pan Jian-Bin Xu Yi Shi College of mechanical and electrical engineering Henan Agricultural University School of Electronic Science and engineering Collaborative Innovation Center of Advanced Microstructures Nanjing University Department of Electronic engineering The Chinese University of Hong Kong

Given the increasing number of diabetic patients,rapid and accurate detection of glucose in body fluids is critical.This study developed a direct electrochemical biosensor for glucose based on nitrogen-doped carbon nanocages （NCNCs）.NCNCs possess a large specific surface area of 1395 m2·g-1,a high N atomic content of 9.37%and good biocompatibility,which is favorable for enzyme loading and electron transfer.The surface average concentration of electroactive glucose oxidase on NCNCs was 2.82×10–10mol·cm-2.The NCNC-based direct electrochemical biosensor exhibited a high sensitivity of 13.7μA·(mmol·L-1)-1·cm-2,rapid response time of 5 s and an impressive electron-transferrate constant （ks） of 1.87 s-1.Furthermore,we investigated an NCNC-based direct electron transfer （DET） biosensor for sweat glucose detection,which demonstrated tremendous promise for non-invasive wearable diabetes diagnosis

关键词： Direct electron transfer (DET) Nitrogen-doped carbon nanocages (NCNCs) Glucose oxidase Biosensor

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Current Status and Perspectives of Dual-Atom Catalysts Towards Sustainable Energy Utilization

引用

Nano-Micro Letters 2024年第7期16卷 402-440页

作者： Yizhe Li Yajie Li Hao Sun Liyao Gao Xiangrong Jin Yaping Li Zhi LV Lijun Xu Wen Liu Xiaoming Sun State Key Laboratory of Chemical Resource engineering Beijing Advanced Innovation Center for Soft Matter Science EngineeringCollege of ChemistryBeijing University of Chemical TechnologyBeijing 100029People’s Republic of China Xinjiang Coal Mine mechanical and electrical engineering Technology Research center Xinjiang Institute of EngineeringUrumqi 830023Xinjiang Uygur Autonomous RegionPeople’s Republic of China

The exploration of sustainable energy utilization requires the imple-mentation of advanced electrochemical devices for efficient energy conversion and storage,which are enabled by the usage of cost-effective,high-performance electro-catalysts.Currently,heterogeneous atomically dispersed catalysts are considered as potential candidates for a wide range of applications.Compared to conventional cata-lysts,atomically dispersed metal atoms in carbon-based catalysts have more unsatu-rated coordination sites,quantum size effect,and strong metal-support interactions,resulting in exceptional catalytic activity.Of these,dual-atomic catalysts(DACs)have attracted extensive attention due to the additional synergistic effect between two adja-cent metal atoms.DACs have the advantages of full active site exposure,high selectiv-ity,theoretical 100%atom utilization,and the ability to break the scaling relationship of adsorption free energy on active sites.In this review,we summarize recent research advancement of DACs,which includes(1)the comprehensive understanding of the synergy between atomic pairs;(2)the synthesis of DACs;(3)characterization meth-ods,especially aberration-corrected scanning transmission electron microscopy and synchrotron spectroscopy;and(4)electrochemical energy-related applications.The last part focuses on great potential for the electrochemical catalysis of energy-related small molecules,such as oxygen reduction reaction,CO_(2) reduction reaction,hydrogen evolution reaction,and N_(2) reduction reaction.The future research challenges and opportunities are also raised in prospective section.

关键词： Dual-atom catalysts Synergetic effect Electrocatalysis Oxygen reduction reaction CO_(2)reduction reaction Hydrogen evolution reaction N2 reduction reaction

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Analysis of deformation mechanisms in magnesium single crystals using a dedicated four-point bending tester

引用

Journal of Magnesium and Alloys 2024年第5期12卷 1911-1917页

作者： Yutaka Yoshida Rikuto Izawa Kenji Ohkubo Faculty of engineering Kitami Institute of Technology Graduate student Department of Mechanical and Electrical Engineering Kitami Institute of Technology Kyokuto Kaihatsu Kogyo Co. Ltd. center for Advanced Research of Materials Faculty of Engineering Hokkaido University

In this study, we explored the deformation mechanisms of Mg single crystals using a combination of scanning electron microscopy and electron backscattered diffraction in conjunction with a dedicated four-point bending tester. We prepared two single-crystal samples,oriented along the and directions, to assess the mechanisms of deformation when the initial basal slip was suppressed. In the sample, the primary {■} twin(T1) was confirmed along the direction of the sample on the compression side with an increase in bending stress. In the sample, T1 and the secondary twin(T2) were confirmed to be along the direction, with an orientation of ±60° with respect to the bending stress direction, and their direction matched with(0001) in T1 and T2. This result implies that crystallographically, the basal slip occurs readily. In addition, the sample showed the double twin in T1 on the compression side and the tertiary twin along the direction on the tension side. These results demonstrated that the maximum bending stress and displacement changed significantly under the bend loading because the deformation mechanisms were different for these single crystals.Therefore, the correlation between bending behavior and twin orientation was determined, which would be helpful for optimizing the bending properties of Mg-based materials.

关键词： Four-point bending Magnesium single crystal Twinning Basal slip Scanning electron microscopy Electron backscatter diffraction

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Study on cumulative effects of biological craniocerebral trauma underrepeated blast

引用

Theoretical & Applied Mechanics Letters 2024年第3期14卷 174-183页

作者： Xingyuan Huang Bingchen Xia Lijun Chang Zhikang Liao Hui Zhao Zhihua Cai Hunan Provincial Key Laboratory of Health Maintenance for mechanical Equipment Hunan University of Science and TechnologyXiangtan 411201China School of mechanical and electrical engineering Foshan UniversityFoshan 528231China Institute for Traffic Medicine PLA Army Characteristic Medical CenterChongqing 400042China

Repeated blast impacts on personnel in explosive environments can exacerbate craniocerebral trauma.Most ex-isting studies focus on the injury effects of a single blast,lacking in-depth analysis on the injury effects andcumulative effects of repeated blasts.Therefore,rats were used as the experimental samples to suffer from ex-plosion blasts with different peak air overpressures(167 kPa∼482 kPa)and varying number of repeated blasts.The cumulative effect of craniocerebral trauma was most pronounced for moderate repeated blast,showing ap-proximately 95%increase of trauma severity with penta blast,and an approximately 85%increase of traumaseverity with penta minor blast.The cumulative effect of craniocerebral trauma from severe,repeated blast has asmaller rate of change compared to the other two conditions.The severity of trauma from penta blast increasedby approximately 69%compared to a single blast.Comprehensive physiological,pathological and biochemicalanalysis show that the degree of neurological trauma caused by repeated blasts is higher than that of single blasts,and the pathological trauma to brain tissue is more extensive and severe.The trauma degree remains unchangedafter double blast,increases by one grade after triple or quadruple blast,and increases by two grades after pentablast.

关键词： Repeated blast Craniocerebral trauma Trauma severity grade Cumulative effects

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Magnetic-Driven Multi-motion Robot with Position/Orientation Sensing Capability

引用

Research 2024年第1期2023卷 675-685页

作者： Liwen Zhang Song Zhao Xinzhao Zhou Xueshan Jing Yu Zhou Yan Wang Yantong Zhu Xiaolin Liu Zehui Zhao Deyuan Zhang Lin Feng Huawei Chen School of mechanical engineering and Automation Beihang UniversityBeijingChina Beijing Advanced Innovation center for Biomedical engineering Beihang UniversityBeijingChina

Miniature magnetic-driven robots with multimode motions and high-precision pose sensing capacity(position and orientation)are greatly demanded in in situ manipulation in narrow opaque enclosed spaces.Various magnetic robots have been carried out,whereas their deformations normally remain in single mode,and the lack of the robot’s real-time status leads to its beyond-sight remagnetization and manipulation being impossible.The function integration of pose sensing and multimode motion is still of challenge.Here,a multimotion thin-film robot is created in a novel multilayer structure with a magneticdriven layer covered by a heating-sensing conductive layer.Such a heating-sensing layer not only can segmentally and on-demand heat the magnetic-driven layer for in situ magnetization reprogramming and multimode motions but also can precisely detect the robot’s pose(position and orientation)from its electrical-resistance effect by creating a small deformation under preset magnetic fields.

关键词： robot Robot motion

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Constructal design of a rectangular porous fin considering minimization of maximum temperature difference and pumping power consumption

引用

Science China(Technological Sciences) 2024年第3期67卷 919-929页

作者： LIU XiaoYe FENG HuiJun CHEN LinGen GE YanLin Institute of Thermal Science and Power engineering Wuhan Institute of TechnologyWuhan 430205China College of Power engineering Naval University of EngineeringWuhan 430033China Hubei Provincial engineering Technology Research center of Green Chemical Equipment Wuhan 430205China School of mechanical&electrical engineering Wuhan Institute of TechnologyWuhan 430205China

A heat dissipation model of a rectangular porous fin is established based on constructal theory. First, the constructal design of rectangular porous fin is conducted by selecting a complex function minimization, which composed of linear weighting sum of maximum temperature difference and pumping power consumption, as optimization objective. Effects of gap height, air inlet velocity, total porous fin volume and porosity on the optimal constructs are investigated, respectively. The findings show that the complex function can attain its double minimum at a value of 0.802 when the fin length and number are optimized, and the corresponding optimal fin length and number are 8.01 mm and 10, respectively. In comparison to original design, the complex function and maximum temperature difference after twice optimization are decreased by 19.80% and 66.31%, respectively.Second, the comprehensive performance of porous fin is improved by simultaneously optimizing the fin length and number. The artificial neural network is applied to predict the fin performances, which is used to conduct multi-objective optimization based on NSGA-II algorithm. Optimal structure of porous fin for multiple requirements is gained by LINMAP and TOPSIS decisionmaking strategies. The findings in this study can serve as theoretical guides for fin thermal designs of electronic devices.

关键词： constructal theory rectangular porous fin pumping power consumption maximum temperature difference complex function multi-objective optimization

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：