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3D Fe-Rich Phases Evolution and its Effects on the Fracture Behavior of Al-7.0Si-1.2Fe Alloys by Mn Neutralization

Acta Metallurgica Sinica(English Letters) 2022年第1期35卷 163-175页

作者： dong-Fu Song Yu-liang Zhao zhi Wang Yi-Wang Jia Dao-xi li Ya-Nan Fu Da-Tong Zhang Wei-Wen Zhang National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials South China University of TechnologyGuangzhou510641China guangdong Provincial Key Laboratory of Metal Toughening Technology and Application Institute of New MaterialsGuangdong Academy of SciencesGuangzhou510650China School of Mechanical Engineering Dongguan University of TechnologyDongguan523808China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai201204China

The evolution of the 3D Fe-rich phases of Al-7.0Si-1.2Fe alloys with different Mn contents was visualized and characterized using synchrotron X-ray computed tomography,and the effect of Fe-rich phases with typical morphologies on the fracture behavior during tensile testing was *** results showed that the Fe-rich phase changed from platelet-likeβ-Al_(5) Fe Si intoα-Al_(15)(Fe Mn)_(3)Si_(2)with various morphologies after the addition of *** Mn addition not only significantly reduced the volume fraction,equivalent diameter and interconnectivity of the Fe-rich phase but also greatly increased the sphericity,surface thickness,and distribution of the mean curvature and surface ***,the equivalent diameter ofα-Al_(15)(FeMn)_(3)Si_(2)had an inverse exponential function relationship with its *** 3D morphology ofα-Al_(15)(FeMn)_(3)Si_(2)can be summarized as massive and regular polyhedrons,hollow and regular polyhedrons,and multibranched *** fraction of the different 3D morphologies in each alloy is related to the Mn content,where excess Mn increased the number and volume fraction of the large Fe-rich particles with a low *** ductility of each alloy was significantly improved by the addition of Mn but gradually decreased when the Mn/Fe ratio exceeded *** increase in largeα-Al_(15)(Mn Fe)_(3)Si_(2)with a low sphericity was the main reason for the decreased ductility of alloys with a high Mn content.

关键词： Synchrotron X-ray tomography Fe-rich phase 3D morphology Fracture behavior

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Sparse Support Vector Machine with Lp Penalty for Feature Selection

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Journal of Computer Science & Technology 2017年第1期32卷 68-77页

作者： Lan Yao Feng Zeng dong-Hui li zhi-gang Chen College of Mathematics and Econometrics Hunan University Changsha 410082 China School of Software Central South University Changsha 410083 China School of Mathematical Sciences South China Normal University Guangzhou 510631 China

We study the strategies in feature selection with sparse support vector machine （SVM）. Recently, the socalled Lp-SVM （0 〈 p 〈 1） has attracted much attention because it can encourage better sparsity than the widely used L1-SVM. However, Lp-SVM is a non-convex and non-lipschitz optimization problem. Solving this problem numerically is challenging. in this paper, we reformulate the Lp-SVM into an optimization model with linear objective function and smooth constraints （LOSC-SVM） so that it can be solved by numerical methods for smooth constrained optimization. Our numerical experiments on artificial datasets show that LOSC-SVM （0 〈 p 〈 1） can improve the classification performance in both feature selection and classification by choosing a suitable parameter p. We also apply it to some real-life datasets and experimental results show that it is superior to L1-SVM.

关键词： machine learning feature selection support vector machine Lp-regularization

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Exploring an eco-friendly approach to improve soil tensile behavior and cracking resistance

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Journal of Rock Mechanics and geotechnical Engineering 2024年第10期16卷 4272-4284页

作者： lin li Chao-Sheng Tang Jin-Jian Xu Yao Wei zhi-Hao dong Bo liu xi-Ying Zhang Bin Shi School of Earth Sciences and Engineering Nanjing UniversityNanjing210023China School of Civil and Environmental Engineering Nanyang Technological University639798Singapore Qinghai Provincial Key Laboratory of geology and Environment of Salt Lake Qinghai Institute of Salt LakesChinese Academy of SciencesXining810008China

Soil tensile strength is a critical parameter governing the initiation and propagation of tensile *** study proposes an eco-friendly approach to improve the tensile behavior and crack resistance of clayey *** validate the feasibility and efficacy of the proposed approach,direct tensile tests were employed to determine the tensile strength of the compacted soil with different W-OH treatment concentrations and water *** tests were also performed to evaluate the effectiveness of W-OH treatment in enhancing soil tensile cracking *** this period,the effects of W-OH treatment concentration and water content on tensile properties,soil suction and microstructure were *** tensile tests reveal that W-OH treatment has a significant impact on the tensile strength and failure mode of the soil,which not only effectively enhances the tensile strength and failure displacement,but also changes the brittle failure behavior into a more ductile quasi-brittle failure *** suction measurements and mercury intrusion porosimetry(MiP)tests show that W-OH treatment can slightly reduce soil suction by affecting skeleton structure and increasing *** with the microstructural analysis,it becomes evident that the significant improvement in soil tensile behavior through W-OH treatment is mainly attributed to the W-OH gel's ability to provide additional binding force for bridging and encapsulating the soil ***,desiccation tests demonstrate that W-OH treatment can significantly reduce or even inhibit the formation of soil tensile *** the increase of W-OH treatment concentration,the surface crack ratio and total crack length are significantly *** study enhances a fundamental understanding of eco-polymer impacts on soil mechanical properties and provides valuable insight into their potential application for improving soil crack resistance.

关键词： Clayey soil Tensile strength Eco-friendly approach Direct tensile test Desiccation cracking Crack resistance

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Aggregate Engineering in Supramolecular Polymers via Extensive Non-covalent Networks

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Chinese Journal of Polymer Science 2021年第10期39卷 1310-1318,I0007页

作者： xin Huang dong Lv li-Qing Ai Shuk Han Cheng xi Yao Department of Biomedical Sciences City University of Hong KongHong Kong 999077China City University of Hong Kong Shenzhen Research InstituteShenzhen 518075China

Aggregate engineering of non-covalent networks endows supramolecular polymers with thermo-mechanical versatility,stimuli-responsive phase transitions and intrinsic damage-healing ***,most non-covalent networks are vulnerable at elevated temperatures,which suppresses the robustness of supramolecular ***,ureidocytosine(UCy)motifs,which are capable of forming extensive non-covalent networks and thus robust molecular aggregates via multivalent hydrogen bonds and aromatic stackings,are proposed to enable precise programming of the thermo-mechanical *** simulations reveal that the enthalpic contributions from the UCy aggregates play dominant roles to compensate the entropic loss from the redistributions of polymeric spacers and stabilize the non-covalent networks over wide temperature *** aggregate-level strategy offers prospects for applications which require thermo-mechanical versatility of supramolecular polymers,such as 3D printing,microfabrication and damage-healing coating.

关键词： Aggregate engineering Damage-healing Extensive non-covalent network Ureidocytosine Supramolecular polymers

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Reconfigurable Muscle Strength Training Robot with Multi-mode Training for 17 Joint Movements

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Journal of Bionic Engineering 2023年第1期20卷 212-224页

作者： Jianfeng li Qiulin Fang Mingjie dong xi Rong liwei Jiang Ran Jiao Beijing Key Laboratory of Advanced Manufacturing Technology Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing100124People’s Republic of China The Affiliated Hospital of Qingdao University Qingdao266000People’s Republic of China The CSSC System Engineering Research institute Beijing100094People’s Republic of China

Different from limb rehabilitation training,the purpose of muscle strength training is to reduce muscle atrophy and increase muscle strength and tolerance through strength training of limb muscles,and then improve the muscle strength level of muscles(groups),mainly for sports fitness and muscle strengthening groups and patients with muscle atrophy or muscle weakness caused by various *** this paper,we developed a new reconfigurable muscle strength training robot,a bionic robot by imitating physicians to conduct muscle strength training for patients,which was developed with six training modes for 17 joint movements,that is,the shoulder flexion/extension,the shoulder internal/external rotation,the shoulder adduction/abduction,the elbow flexion/extension,the wrist supination/pronation,the wrist flexion/extension,the wrist radial/ulnar deviation,the hip flexion/extension,the hip internal/external rotation,the hip adduction/abduction,the knee flexion/extension,the ankle dorsiflexion/plantarflexion,the ankle adduction/abduction,the ankle inversion/eversion,the waist flexion/extension,the waist left/right rotation,and the waist left/right *** reconfigurable mechanism was designed with fully electric adjuster and reconfigurable adaptors deployed on the driving unit,and six training modes were developed,namely,continuous passive motion,active exercise,passive–active exercise,isotonic exercise,isometric exercise and isokinetic *** with knee joint and elbow joint have shown that the developed reconfigurable muscle strength training robot can realize the multi-mode trainings for the 17 joint movements.

关键词： Reconfigurable mechanism Bionic robot Muscle strength training 17 joint movements Multi-mode trainings

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iNFLUENCE OF STRUCTURE ON HYDRAUliC CHARACTERiSTiCS OF T SHAPE FiSHWAY

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Journal of Hydrodynamics 2012年第5期24卷 684-691页

作者： MAO xi FU Jing-jing TUO You-cai AN Rui-dong li Jia State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065China HydroChina Hua dong Engineering Corp.9 Hangzhou 310014 China

While dams cut off the migratory route of fish, and affect their growth and breeding, fishways are built to restore the con- nectivity of rivers and facilitate the life cycle of these migratory fish. This paper proposes a new kind of fishway called the ＂T shape fishway＂, and studies it by using both numerical simulations and physical experimental methods with the aim to design a fishway in China for migratory fish with swimming and jumping capability much poorer, such as schizothorax davidi and schizothorax prenanti, as compared with migratory fish in other places of the world, like trout and salmon. it is indicated that the range of velocity in each regular pool of the T shape fishway is from 0.42 m/s to 1.22 m/s when the flow discharge Q is 350 L/s, and there are no large vortex zones found there. This study shows that the T shape fishway can meet the requirements of these migratory fish quite well in terms of velocity and flow patterns in China.

关键词： fishway migratory fish baffle drop sill numerical simulation experiment

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influence of friction-lubrication characteristics varying with rolling speed on instability of chatter and slip in cold tandem rolling process

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Journal of iron and Steel Research international 2024年第4期31卷 894-908页

作者： Yan-li xin zhi-ying gao Bo Tian Qing-dong Zhang School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China

in the high-speed cold tandem rolling process of thin plate,chatter or slip instability gives rise to the deterioration of equipment and product *** instability behavior is closely related to interfacial friction-lubrication con-dition which is generally characterized by the friction ***,with higher and higher speed requirements,the commonly used model of friction coefficient is no longer applicable and accurate.A novel approach is suggested to calculate the speed-dependent friction coefficient,in which the viscosity-pressure-temperature effects of the lubricant,surface roughness states of work rolls and rolled piece are comprehensively involved and the mixed flm lubrication theory is ***,the influences of friction coefficient on the instability of slip and chatter are investigated for a five-stand cold tandem rolling *** one side,the critical friction coefficient for each stand is determined by calculating the corresponding slip factor;on the other hand,the friction coefficient varying with rolling speed is combined with the model of theoretical critical rolling speed presented under constant friction coefficient,so that the speed threshold is ***,the stable and unstable regions corresponding to the rear three stands are individually discussed,and the technical strategies are proposed to suppress both slip and chatter frequently occurring in the actual rolling process.

关键词： Cold tandem rolling:Oil film thickness Speed-dependent friction coefficient-Slip:Chatter

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A Double-Stage Surrogate-Based Shape Optimization Strategy for Blended-Wing-Body Underwater gliders

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China Ocean Engineering 2020年第3期34卷 400-410页

作者： li Cheng-shan WAng Peng QiU zhi-ming dong Hua-chao School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an 710072China

in this paper,a Double-stage Surrogate-based Shape Optimization(DSSO)strategy for Blended-Wing-Body Underwater gliders(BWBUgs)is proposed to reduce the computational *** this strategy,a double-stage surrogate model is developed to replace the high-dimensional objective in shape ***,several First-stage Surrogate Models(FSMs)are built for the sectional airfoils,and the second-stage surrogate model is constructed with respect to the outputs of ***,a Multi-start Space Reduction surrogate-based global optimization method is applied to search for the *** order to validate the efficiency of the proposed method,DSSO is first compared with an ordinary One-stage Surrogate-based Optimization strategy by using the same optimization ***,the other three popular surrogate-based optimization methods and three heuristic algorithms are utilized to make *** indicate that the lift-to-drag ratio of the BWBUg is improved by 9.35%with DSSO,which outperforms the comparison ***,DSSO reduces more than 50%of the time that other methods used when obtaining the same level of ***,some considerations of the proposed strategy are further discussed and some characteristics of DSSO are identified.

关键词： shape optimization double-stage surrogate model kriging blended-wing-body underwater glider lift-to-drag ratio

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Ultra-thin ALD CoO_(x)-ZnO heterogenous films as highly sensitive and environmentally friendly H_(2)S sensor

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Rare Metals 2023年第9期42卷 3054-3063页

作者： Qing-Min Hu Zhe dong gai-xia Zhang Yu-xi li Shuang-Feng xing zhi-Heng Ma Bo-Yu dong Bo Lu Shu-Hui Sun Jia-Qiang Xu NEST Lab Department of ChemistryCollege of ScienceShanghai UniversityShanghai200444China institut National de la Recherche Scientifique-Énergie Matériaux et Télécommunications Varennes VarennesQCJ3X 1S2Canada State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan030001China

To obtain environmentally friendly,integrated and miniaturized gas sensors for the increasing request for the internet of Things industry and other relative areas,the ultra-thin CoO_(x)/Zn O heterogeneous film with active interfacial sites was in-situ deposited on micro-electro-mechanical systems(MEMS)as H_(2)S *** layer deposition(ALD)was employed to in-situ fabricate the uniform Zn O thin *** CoO_(x)was deposited on ZnO surface to obtain CoO_(x)/Zn O heterojunction and active interfacial *** ultra-thin film(20 nm)with 50 ALD Co O_(x)decorated on 250 ALD Zn O displays excellent sensing performance,including very high response(4.45@200×10^(-9))and selectivity to H_(2)S with a limit of detection(LOD)of 0.38×10^(-9),long-term sensing stability,high response/recovery performance(7.5 s/15.7 s)and mechanical strength at 230。*** for the high sensing performance of CoO_(x)/Zn O have been confirmed by series of characterizations and density functional theory(DFT)*** film thickness with Debye length,the oxygen vacancies and the synergistic effect of active interfacial sites are main reasons for the high sensing *** strategy by fabrication of CoO_(x)/Zn O heterogeneous film within Debye length and employing synergistic effect of active interfacial sites offers a promising route for the design of environmentally friendly gas ***,the ALD technique offers a facile in-situ strategy and high-throughput fabrication of MEMS gas sensors.

关键词： Atomic layer deposition(ALD) Surface decoration CoO_(x)/ZnO active interfacial sites H_(2)S gas sensor

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Photographic Appearance Enhancement via Detail-Based Dictionary Learning

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Journal of Computer Science & Technology 2017年第3期32卷 417-429页

作者： zhi-Feng xie Shi Tang dong-Jin Huang You-dong Ding li-Zhuang Ma Department of Film and Television Engineering Shanghai University Shanghai 200072 China Shanghai Engineering Research Center of Motion Picture Special Effects Shanghai 200072 China Department of Computer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China

A number of edge-aware filters can efficiently boost the appearance of an image by detail decomposition and enhancement. However, they often fail to produce photographic enhanced appearance due to some visible artifacts, especially noise, halos and unnatural contrast. The essential reason is that the guidance and the constraint of high-quality appearance are not sufficient enough in the process of enhancement. Thus our idea is to train a detail dictionary from a lot of high-quality patches in order to constrain and control the entire appearance enhancement. in this paper, we propose a novel learning-based enhancement method for photographic appearance, which includes two main stages： dictionary training and sparse reconstruction. in the training stage, we construct a training set of detail patches extracted from some high-quality photos, and then train an overcomplete detail dictionary by iteratively minimizing an？1-norm energy function. in the reconstruction stage, we employ the trained dictionary to reconstruct the boosted detail layer, and further formalize a gradient-guided optimization function to improve the local coherence between patches. Moreover, we propose two evaluation metrics to measure the performance of appearance enhancement. The final experimental results have demonstrated the effectiveness of our learning-based enhancement method.

关键词： image enhancement dictionary learning edge-aware filter

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