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SSRN 2022年

作者： Song, Dongfu Zhao, Yuliang Jia, Yiwang Huang, Guangyao Zhang, Zhibo Zhou, Nan Li, Xintao Zheng, Kaihong Fu, Yanan Zhang, Weiwen Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application Institute of New Materials Guangdong Academy of Sciences Guangzhou510650 China National Engineering Research Centre of Near-net-shape Forming for Metallic Materials South China University of Technology Guangzhou510641 China Neutron Scattering Technical Engineering Research Centre School of Mechanical Engineering Dongguan University of Technology Dongguan523808 China Jiangxi Universal New Material Technology Co. Ltd Shangrao334499 China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research Institute CAS Shanghai201204 China

Boron (B) is an effective grain refiner in Al-Si alloys, but the modification mechanism of B on the formation and solidification behaviour of Fe-rich phases is still in debate. In this paper, we used in situ synchrotron X-ray radiography, combined with thermodynamics and first-principles calculations, to study the influence of B on the evolution and solidification behaviour of microstructure of Fe-rich phases in Al-7Si-xFe (x=1.2~3.0) alloys. The results showed that B had an excellent influence on the refinement of α-Al grains in Al-7Si-1.2Fe alloys, but it had no obvious effect on the morphology and distribution of Fe-rich phases due to the eutectic reaction to form Al-AlB 2 . B had a certain refining effect on primary Fe-rich phases in Al-Si-Fe alloys with high Fe content (≥2.36 wt.%), but it did not totally prevent the formation of these phases. The results of in situ synchrotron X-ray radiography showed that the addition of B significantly reduced the formation temperature of primary Fe-rich phases. The first-principles calculations showed that the adsorption energy of B on the surface of α-Al 2 O 3 (0001) was significantly higher than that of Fe, which inhibited the nucleation of the primary Fe-rich phase above the Al-AlB 2 eutectic temperature and promoted its supercooling of nucleation. Furthermore, many α-Al nuclei formed during the transition to the Al-AlB 2 eutectic;their subsequent growth hindered the development of the primary iron-rich phase. These were the main reasons for the refinement of the primary Fe-rich phases. The results of this study provide insights for designing recycled Al-Si alloys and fundamental knowledge of Fe-rich phase modification by B addition. © 2022, The Authors. All rights reserved.

关键词： Silicon alloys

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A Model for Predicting Dynamic Cutting Forces in Sand Mould Milling with Orthogonal Cutting

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Chinese Journal of Mechanical Engineering 2018年第6期31卷 95-105页

作者： Zhong-De Shan Fu-Xian Zhu State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science TechnologyBeijing 100083China Jiangsu University of Technology Changzhou 213001China

Cutting force is one of the research hotspots in direct sand mould milling because the cutting force directly a ects the machining quality and tool wear. Unlike metals, sand mould is a heterogeneous discrete deposition material. There is still a lack of theoretical research on the cutting force. In order to realize the prediction and control of the cut?ting force in the sand mould milling process, an analytical model of cutting force is proposed based on the unequal division shear zone model of orthogonal cutting. The deformation velocity relations of the chip within the orthogonal cutting shear zone are analyzed first. According to the flow behavior of granular, the unequal division shear zone model of sand mould is presented, in which the governing equations of shear strain rate, strain and velocity are estab?lished. The constitutive relationship of quasi?solid–liquid transition is introduced to build the 2D constitutive equation and deduce the cutting stress in the mould shear zone. According to the cutting geometric relations of up milling with straight cutting edge and the transformation relationship between cutting stress and cutting force, the dynamic cutting forces are predicted for di erent milling conditions. Compared with the experimental results, the predicted results show good agreement, indicating that the predictive model of cutting force in milling sand mould is validated. Therefore, the proposed model can provide the theoretical guidance for cutting force control in high e ciency mill?ing sand mould.

关键词： Green manufacture Cutting force Sand mould milling Orthogonal cutting Quasi?solid–liquid transition

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Effect of the configuration and concentration of B-doping on the thermal properties and structural stability of graphene: A theoretical study

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Diamond and Related Materials 2025年 156卷

作者： Li, Dongbo Da, Liangguo Huang, Kaifeng Li, Dong Yu, Liang Wang, Haini Yu, Yaqi Wu, Long Tang, Yunqing School of Mechanical and Electrical Engineering Huainan Normal University Huainan232038 China Human-computer collaborative robot Joint Laboratory of Anhui Province Huainan232038 China School of Mechanical Engineering Shandong University Jinan250061 China State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Jinan250061 China Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of Education Shandong University Jinan250061 China

The thermal properties and structural stability of B-doped graphene were investigated by employing density functional theory (DFT), ab initio molecular dynamics (AIMD), and molecular dynamics (MD) simulations, with a focus on the effects of doping configuration and concentration. DFT calculations indicate that B-doping reduces the cohesive energy of graphene, consequently diminishing its structural stability. Among the three B double-doping configurations, only the para configuration exhibits a phonon dispersion without imaginary frequencies, whereas both meta and ortho configurations show imaginary frequencies, indicating structural instability. The AIMD results further demonstrate that B-doped graphene preferentially undergoes cleavage at B[sbnd]B bonds, leading to decreased structural stability. MD results show that B-doping significantly reduces the thermal conductivity of graphene. At a doping concentration is 0.6 %, the thermal conductivity of meta and para configurations decreases to 48.08 % and 54.6 % of that of the pristine graphene, respectively. The results of phonon properties show that B-doping reduces the phonon participation rate and induces strong phonon localization at the B-doped site. These results and conclusions will provide valuable theoretical insights for the thermal design of graphene-based semiconductor devices. © 2025 Elsevier B.V.

关键词： Temperature distribution

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Effect of Bearing Structure on Oil-air Flow and Temperature of High Speed Ball Bearing by Combining Nonlinear Dynamic and CFD Model

Research Square

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Research Square 2021年

作者： Deng, Song Zhao, Gui Qiang Qian, Dong-Sheng Hua, Lin Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan430070 China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of Technology Wuhan430070 China Hubei Research Center for New Energy & Intelligent Connected Vehicle Wuhan University of Technology Wuhan430070 China Hubei Engineering Research Center for Green Precision Material Forming Wuhan University of Technology Wuhan430070 China

To achieve effective cooling for high speed ball bearings, an investigation on the effect of bearing structure on oil-air flow and temperature inside bearing chamber is necessary. However, accurately defining boundary conditions of CFD model for high speed ball bearings has not been addressed completely. Adopting an improved dynamic model of bearings to calculate movements of balls and power loss to set the movement boundary and heat source of CFD model at high-low speeds and light-heavy loads. Then, rotational speed of cage and temperature of outer ring at various loads are tested to validate this proposed method. At high speeds, enlarging sealing degree of outlet not only reduces the temperature rise of bearings and improves the uniformity of temperature distribution, but also promotes the formation of oil-film on balls’ surfaces without increasing power loss. Yet it can reduce the temperature rise but can’t markedly improve the formation of oil-film at low and ultra-high speeds. Moreover, half birfield cage facing nozzle plays an important role in improving oil volume fraction inside the bearing cavity to reduce the temperature rise of bearings, and the next is birfield cage, they are again corrugated cage and half birfield cage back towards nozzle. These research results provide theoretical guidance for the improvement of bearing structure. © 2021, CC BY.

关键词： Air

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The Effect of Aging Treatment on Microstructure and Corrosion Resistance of 7××× Series Aluminum Alloy

The Effect of Aging Treatment on Microstructure and Corrosio...

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Artificial Intelligence and Electromechanical Automation (AIEA), International Conference on

作者： Chunming Li Feng Zhang Yong Yang Yunbo Chen Lingli Zuo Yang Zhang Lin Chen State Key Laboratory of Advanced Forming Technology and Equipment Beijing National Innovation Institute of lightweight Ltd Beijing Anhui Fenghui Metal Co. Ltd. Fuyang

ISBN: (数字)9781728182889

ISBN: (纸本)9781728182896

the influence of aging treatment on the microstructure and corrosion resistance of 7××× series aluminum alloy was studied by means of microstructure analysis, energy spectrum analysis, tensile test and intergranular corrosion test. The results show that the tensile strength, yield strength and elongation of alloy after peak-aging (121°C / 24 h) treatment are 605.3 MPa, 501.9 MPa and 8.6%, respectively, but which corrosion resistance is the worst; the strength of over-aged (121°C / 6 h + 177°C / 8 h) is significantly lower than that of peak-aging, but it has highest elongation, reaching 11.9%, besides, its corrosion resistance is the best; the strength of interrupted ageing (121°C / 0.5 h (water cooling) + 65°C / 240 h + 121°C / 24 h) alloy is the highest, and the corrosion resistance is better than those of peak-aging.

关键词： 7 ××× aluminum alloy aging treatment corrosion resistance corrosion resistance ageing treatment Microstructure aluminium alloys peaks

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Dynamics analysis and simulation of a new 6-DOF lower limb rehabilitation robot 2

Dynamics analysis and simulation of a new 6-DOF lower limb r...

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2nd International Symposium on Application of Materials Science and Energy Materials, SAMSE 2018

作者： Wang, Hongbo Lin, Musong Yan, Yonggan Liu, Guowei Su, Bowen Zhao, Chaosheng Wang, Fuhao Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao China Key Laboratory of Advanced Forging and Stamping Technology and Science Ministry of Education Yanshan University Qinhuangdao China Academy for Engineering and Technology Fudan University Shanghai China

This paper proposes a new hybrid (parallel-serial) 6-DOF lower limb rehabilitation robot including two mechanical legs and an adjustable seat, which could train in sitting, lying and standing three postures. Each mechanical leg consists of hip joint, knee joint and ankle joint. The dynamics and DOF of the robot are analysed, and the result is verified by the software ADAMS. The result lay the foundation for prototype build in future. © Published under licence by IOP Publishing Ltd.

关键词： Joints (anatomy)

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Comfort degree of patients' rehabilitation training based on DSmT theory 2

Comfort degree of patients' rehabilitation training based on...

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2nd International Symposium on Application of Materials Science and Energy Materials, SAMSE 2018

作者： Wang, Hongbo Yan, Hao Niu, Baoshan Wang, Xincheng Li, Yafeng Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao China Key Laboratory of Advanced Forging and Stamping Technology and Science Ministry of Education Yanshan University Qinhuangdao China Academy for Engineering and Technology Fudan University Shanghai China

This paper aims to solve the problem that most rehabilitation robots lack to integrate their physiological functions and psychological states into closed controlling loop in rehabilitation training of stroke patients. The application of fusion technology of multi-electromechanical sensor signal and DSmT signal is used to achieve patients' comfort judgement. Mean value and variance are used to extract physiological information such as heart rate, temperature and skin resistance. Sensor information of fusion technology of rehabilitation robot based on classical DSmT theory can realize on-line diagnosis of multi-comfort degree of patients' coupling. © Published under licence by IOP Publishing Ltd.

关键词： Patient rehabilitation

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[email protected] Ti 3 C 2 T x @Ni particles with enhanced microwave absorption properties and prolonged stability

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Materials Research Bulletin 2023年 164卷

作者： Weimin Xu Shibo Li Weiwei Zhang Shujun Hu Wenbo Yu Yang Zhou Center of Materials Science and Engineering School of Mechanical and Electronic Control Engineering Beijing Jiaotong University Beijing 100044 China State Key Laboratory of Advanced Forming Technology and Equipment Beijing National Innovation Institute of Lightweight Ltd. Beijing 100083 China

2D Ti 3 C 2 T x MXene with a multi-layered structure and surface functional groups exhibits an ability to attenuate electromagnetic energy through the dielectric loss mechanism. However, the absence of magnetic properties causes its unmatched impedance and poor MA performance. In addition, as exposed to air, oxidization of Ti 3 C 2 T x generally starts from its nanosheet edges and gradually expands to the inside, causing severe oxidative degradation within days and thus restricting its industrial applications. Here, [email protected] structured Ti 3 C 2 T x @Ni particles were prepared by electroless plating. The plated thinner Ni(P) shell endows the modified Ti 3 C 2 T x particles with good impedance matching with microwaves. A minimum reflection loss (RL min ) value of -48.34 dB was achieved in the Ti 3 C 2 T x @Ni particles, better than the RL min of ∼ -11 dB for the pristine Ti 3 C 2 T x . The [email protected] Ti 3 C 2 T x @Ni particles are particularly attractive in its storage stability. As compared with the fast and oxidation of Ti 3 C 2 T x within 12 weeks, the as-prepared Ti 3 C 2 T x @Ni particles are stable up to a year in air because the Ni shell prevents Ti 3 C 2 T x nanosheets from oxidative degradation.

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Theoretical modelling for accurate prediction of transient rapid temperature rise variation within whole tool tip area

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Applied Thermal Engineering 2025年 278卷

作者： Lirui Zheng Jinfu Zhao Zhanqiang Liu Bing Wang Xiaoping Ren Pengyang Wang School of Mechanical Engineering Shandong University China State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Jinan 250061 China Key Laboratory of High Efficiency and Clean Mechanical Manufacture of Ministry of Education Shandong University Jinan 250061 China Key National Demonstration Center for Experimental Mechanical Engineering Education Shandong University Jinan 250061 China School of Mechanical Electrical & Information Engineering Shandong University Weihai 264209 China Faculty of Science and Technology University of Macau Macau E11 China

Cutting temperature modelling aids in the prediction of cutting tool wear. Previous studies have focused on steady state cutting temperature modelling and evaluation, neglecting the prediction performance of the temperature variation at the initial cutting stage, where the cutting temperature rises rapidly and the quasi-steady-state is reached quickly. This research develops a two-dimensional tool tip transient cutting temperature model based on the finite volume method (FVM) with a structured grid but without grid-generation computation. This model comprehensively considers nonlinear heat conduction and tool rake face jet cooling. The proposed models with different assumptions of tool flank face boundary conditions are verified by a high-speed infrared (IR) camera. The isothermal tool flank face assumption best simulates the time for the cutting temperature to reach a steady state ( t st ), with a mean absolute error (MAE) of 4.40 ms. The strong convection tool flank face assumption can predict temperature variations during the initial cutting stage, with a minimum mean absolute percentage error (MAPE) of 20.31 %. The influence mechanisms of the tool flank face convection heat transfer coefficient assumption and cutting speed (the main factors influencing temperature) on the model solution are discussed. The results show that the simulated steady state temperature and t st decay in a double-exponential summation form with the increase of the tool flank face convection coefficient. A high cutting speed induces a higher steady state temperature, but t st is reduced to a decay limit.

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Developing Patient-Derived 3D-Bioprinting models of pancreatic cancer

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Journal of advanced Research 2024年

作者： Sun, Hang Wang, Yan Sun, Minghao Ke, Xindi Li, Changcan Jin, Bao Pang, Mingchang Wang, Yanan Jiang, Shangze Du, Liwei Du, Shunda Zhong, Shouxian Zhao, Haitao Pang, Yuan Sun, Yongliang Yang, Zhiying Yang, Huayu Mao, Yilei Department of Liver Surgery Peking Union Medical College (PUMC) Hospital Peking Union Medical College (PUMC) & Chinese Academy of Medical Sciences (CAMS) Beijing 100730 China Liver Transplantation Center National Clinical Research Center for Digestive Diseases Beijing Friendship Hospital Capital Medical University Beijing 100730 China Eight-year MD Program Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100730 China Department of General Surgery Beijing Chaoyang Hospital Capital Medical University Beijing 100020 China State Key Laboratory of Medical Molecular Biology Department of Physiology Institute of Basic Medical Sciences and School of Basic Medicine Peking Union Medical College and Chinese Academy of Medical Sciences Beijing 100005 China Biomanufacturing Center Department of Mechanical Engineering Tsinghua University Beijing 100084 China Biomanufacturing and Rapid Forming Technology Key Laboratory of Beijing Beijing 100084 China Key Laboratory for Advanced Materials Processing Technology Ministry of Education Beijing 100084 China First Department of Hepatopancreatobiliary Surgery China-Japan Friendship Hospital Beijing 100029 China

Introduction: Pancreatic cancer (PC) remains a challenging malignancy, and adjuvant chemotherapy is critical in improving patient survival post-surgery. However, the intrinsic heterogeneity of PC necessitates personalized treatment strategies, highlighting the need for reliable preclinical models. Objectives: This study aimed to develop novel patient-derived preclinical PC models using three-dimensional bioprinting (3DP) technology. Methods: Patient-derived PC models were established using 3DP technology. Genomic and histological analyses were performed to characterize these models and compare them with corresponding patient tissues. Chemotherapeutic drug sensitivity tests were conducted on the PC 3DP models, and correlations with clinical outcomes were analyzed. Results: The study successfully established PC 3DP models with a modeling success rate of 86.96%. These models preserved genomic and histological features consistent with patient tissues. Drug sensitivity testing revealed significant heterogeneity among PC 3DP models, mirroring clinical variability, and potential correlations with clinical outcomes. Conclusion: The PC 3DP models demonstrated their utility as reliable preclinical tools, retaining key genomic and histological characteristics. Importantly, drug sensitivity profiles in these models showed potential correlations with clinical outcomes, indicating their promise in customizing treatment strategies and predicting patient prognoses. Further validation with larger patient cohorts is warranted to confirm their potential clinical utility. © 2024

关键词： Individualized therapy, adjuvant chemotherapy, tumor heterogeneity Pancreatic cancer Preclinical model Three-dimensional bioprinting

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