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Chinese Chemical Letters 2024年第9期35卷 309-314页

作者： Weichen Zhu Wei Zuo Pu Wang Wei Zhan Jun Zhang Lipin Li Yu Tian Hong Qi Rui Huang State Key Laboratory of Urban Water Resource and Environment(SKLUWRE) School of EnvironmentHarbin Institute of TechnologyHarbin 150090China Guangdong Yuehai Water Investment co. Ltd.Shenzhen 518021China National Engineering Research Center of Urban Water Resources co. Ltd.Harbin Institute of TechnologyHarbin 150090China

Fe-N-C materials have received increasing attention,due to its distinctive catalytic ***,the Fe-N co.rdination number dependence of catalytic ability and mechanism for H_(2)O_(2)activation remain ***,a series of Fe-N-C heterogeneous Fenton-like catalysts with different Fe-N co.rdination number were prepared for tetracycline *** results demonstrated that samples with Fe-N4 structure exhibited high *** excellent performance was mainly ascribed to the high adsorption capacity and the formation of superoxide radicals(•O_(2)^(−))catalyzed by Fe linked to pyridinic *** intermediates and degradation pathways of tetracycline degradation by Fe-N-C/H_(2)O_(2)system were analyzed by liquid chromatography co.pled to tandem mass spectrometry(LC-MS/MS).Furthermore,we applied our Fe-N-C catalysts to treat simulated pharmaceutical wastewater with high tetracycline degradation capacity despite high co.centrations of organic matter such as oxalic acid and various ionic *** work reveals the dependence of the activation H_(2)O_(2)on the Fe-N co.rdination environment and the degradation mechanism of these *** provides insights into the prospects for tuning the catalyst in practical applications.

关键词： H_(2)O_(2)activation Advanced oxidation process Superoxide radicals Degradation pathways EXAFS

Microstructure and properties of 35 kg large aluminum alloy flywheel housing co.ponents formed by squeeze casting with local pressure co.pensation

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China Foundry 2024年第5期21卷 563-576页

作者： Ju-fu Jiang Jing Yan Ying-ze Liu Ning Ge Ying Wang Chang-jie Ding De-chao Zou School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Mechatronics Engineering Harbin Institute of TechnologyHarbin 150001China Dalian Innovation Die-casting co. Ltd.Dalian 116600LiaoningChina

The squeeze casting method with local pressure co.pensation was proposed to form a flywheel housing co.ponent with a weight of 35 *** numerical simulation,microstructure observation and phase characterization were performed,and the influence of local pressure co.pensation on feeding of thick-wall position,microstructure and mechanical properties of the formed co.ponents were *** show that the molten metal keeps a good fluidity and the filling is co.plete during the filling *** the solidification at thick-wall positions of the mounting ports is slow,the local pressure co.pensation effectively realizes the local forced feeding,significantly eliminating the shrinkage cavity *** the microstructure of AlSi9Mg alloy,α-Al primarily co.sists of fragmented dendrites and rosette grains,while eutectic Si predominantly co.prises needles and short *** impact of local pressure co.pensation on strength is relatively minimal,yet its influence on elongation is *** local pressure co.pensation,the average elongation at the co.pensated areas is 9.18%,which represents a 44.90%higher than that before *** average tensile strength is 209.1 MPa,and the average yield strength is 100.6 *** local pressure co.pensation can significantly reduce or even eliminate the internal defects in the 35 kg large-weight co.ponents formed by squeeze casting.

关键词： squeeze casting local pressure co.pensation aluminum alloy microstructure mechanical properties large flywheel housing co.ponents

Neural Network Robust co.trol Based on co.puted Torque for Lower Limb Exoskeleton

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 83-99页

作者： Yibo Han Hongtao Ma Yapeng Wang Di Shi Yanggang Feng Xianzhong Li Yanjun Shi Xilun Ding Wuxiang Zhang School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Beihang Goer(WeiFang)Intelligent Robot co. Ltd.Beihang UniversityWeifangChina Research Center of Satellite Technology Harbin Institute of TechnologyHarbinChina Beijing Xinfeng Aerospace Equipment co. LtdBeijingChina

The lower limb exoskeletons are used to assist wearers in various scenarios such as medical and industrial *** modeling errors of the exoskeleton in different application scenarios pose challenges to the robustness and stability of its co.trol *** Radial Basis Function(RBF)neural network is used widely to co.pensate for modeling *** order to solve the problem that the current RBF neural network co.trollers cannot guarantee the asymptotic stability,a neural network robust co.trol algorithm based on co.puted torque method is proposed in this paper,focusing on trajectory *** innovatively inco.porates the robust adaptive term while introducing the RBF neural network term,improving the co.pensation ability for modeling *** stability of the algorithm is proved by Lyapunov method,and the effectiveness of the robust adaptive term is verified by the *** wearing the exoskeleton under different walking speeds and scenarios were carried out,and the results show that the absolute value of tracking errors of the hip and knee joints of the exoskeleton are co.sistently less than 1.5°and 2.5°,*** proposed co.trol algorithm effectively co.pensates for modeling errors and exhibits high robustness.

关键词： Lower limb exoskeleton Model co.pensation RBF neural network co.puted torque method

Numerical Simulations of Snow Accumulation in the Bogie Region of a Train co.sidering Snow Particle Rotation

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Fluid Dynamics & Materials Processing 2024年第10期20卷 2337-2352页

作者： Hong Lan Jiye Zhang Yao Zhang Lu Cai State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China co.lege of Railway Transportation Hunan University of TechnologyZhuzhou412000China GD Midea air-conditioning Equipment co. Ltd.Foshan528311China

To investigate the influence of snow particle rotational motion on the accumulation of snow in the bogie region of high-speed trains,an Euler‒Lagrange numerical approach is *** study examines the effects of snow particle diameter and train speed on the ensuing *** is shown that co.sidering snow particle rotational motion causes significant deviation in the particle trajectories with respect to non-rotating *** a deviation increases with larger snow particle diameters and higher train *** snow accumulation on the overall surface of the bogie increases,and the amount of snow on the vibration reduction device varies *** certain co.ditions,the amount of accumulated snow can increase by several orders of magnitudes.

关键词： High-speed train bogie snow particle rotation discrete phase model snow accumulation

A double-layer radiative co.ling co.ting that utilizes the refractive index difference between layers to achieve extremely high solar reflectivity

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Science China Technological Sciences 2024年第10期67卷 3182-3189页

作者： WANG FuQiang LI ChunZhe YANG ZhenNing XIE WeiXin LI Xiang XU ZengHui YAN YuYing CHENG ZiMing School of Energy Science and Engineering Harbin Institute of Technology School of New Energy Harbin Institute of Technology at Weihai China co.struction Eco.Environmental Protection Technology co. Ltd. Faculty of Engineering University of Nottingham

Passive daytime radiative co.ling（PDRC） technology has great potential in reducing co.ling energy co.sumption. In order to further improve the spectral performance of PDRC co.tings, current researchers mostly focus on the selection and size design of functional particles, while ignoring the optical properties enhancement effect caused by the interlayer binder. In this study, based on the principle that the refractive index difference between layers enhanced the backscattering performance of the solar spectrum, we proposed and manufactured a double-layer PDRC co.ting with polyvinylidene difluoride（PVDF） as the filmforming material in the upper layer and polydimethylsiloxane（PDMS） as the film-forming material in the lower layer, both filled with Al2O3and SiO2particles. The double-layer PDRC co.ting exhibited excellent spectral performance that a high solar reflectivity of 98% and an emissivity of 0.95 at the “atmospheric window” band. In co.parison, the solar spectrum reflectivity of the single-layer PDRC co.tings based on PVDF and PDMS of the same thickness was 95% and 94.7%, respectively. Outdoor tests showed that the PDRC co.ting achieved a temperature decrease of up to 7.1℃ under direct sunlight at noon time. In addition, the PDRC co.ting had excellent weather resistance, water resistance, and other basic properties. This article opens up a new idea and provides methodological guidance for the design of double-layer PDRC co.tings.

关键词： double-layer radiative co.ling co.ting spectral modulation interlayer refractive index solar energy radiative transfer

Modification of BCC phase and the enhanced reversible hydrogen storage properties of Ti-V-Fe-Mn alloys with varied V/Fe ratios

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China Foundry 2024年第5期21卷 546-554页

作者： Xiang-feng Ma Xin Ding En-lai Liu Rui-run Chen Xin-xiu Wang Yong Zhang and Jing-jie Guo National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering Shandong University of Science and TechnologyQingdao 266500ShandongChina AECC Harbin Dongan Engine Co.Ltd.Harbin 150001China

Ti-V-based alloys are proved of huge potential in storing hydrogen,but the inco.plete reversible hydrogen storage capacity caused by overstability of V hydride has limited the large-scale *** this study,Ti_(32)V_(40+x)Fe_(23-x)Mn_(5)(x=0,4,8,12,at.%)alloys were designed,and the effects of V/Fe ratio on phase co.stitution and hydrogen storage properties were *** main phase of the alloys is body-centered cubic(BCC)phase,and the lattice co.stants of the BCC phase decrease with the decrease of V/Fe ***,C14 Laves phase exists in alloys with a Fe co.tent of 19at.%to 23at.%.For hydrogenation,the C14 Laves phase can accelerate the hydrogen absorption rate,but the hydrogen absorption capacity is *** the decrease of V/Fe ratio,the hydride gradually *** to its large lattice co.stant and high hydrogen absorption phase co.tent,the Ti_(32)V_(52)Fe_(11)Mn_(5)alloy shows the most enhanced hydrogen storage properties with hydrogenation and dehydrogenation capacities of 3.588wt.%at 298 K and 1.688wt.%at 343 K,*** hydrogen absorption capacity of this alloy can be reserved to 3.574wt.%after 20 cycles of hydrogen absorption and desorption.

关键词： hydrogen storage Ti-based alloy lattice co.stant BCC phase

Petroleum pitch derived hard carbon via NaCl-template as anode materials with high rate performance for sodium ion battery

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Frontiers of Chemical Science and Engineering 2024年第7期18卷 1-10页

作者： Baoyu Wu Hao Sun Xiaoxue Li Yinyi Gao Tianzeng Bao Hongbin Wu Kai Zhu Dianxue Cao Key Laboratory of Superlight Materials and Surface Technology of Ministry of Education College of Materials Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001China Hunan Hongshan New Energy Technology co. LtdYiyang 413000China

Sodium-ion batteries(SIBs)have garnered significant interest in energy storage due to their similar working mechanism to lithium ion batteries and abundant reserves of sodium *** facile synthesis of a carbon-based anode materials with capable electrochemical performance is key to promoting the practical application of *** this work,a co.bination of petroleum pitch and recyclable sodium chloride is selected as the carbon source and template to obtain hard carbon(HC)anode for *** times and temperatures are optimized by assessing the sodium ion storage behavior of different HC *** optimized HC exhibits a remarkable capacity of over 430 mAh·g^(-1) after undergoing full activation through 500 cycles at a density of current of 0.1 A·g^(-1).Furthermore,it demonstrates an initial discharge capacity of 276 mAh·g^(-1) at a density of current of 0.5 A·g^(-1).Meanwhile,the optimized HC shows a good capacity retention(170 mAh·g^(-1) after 750 cycles)and a remarkable rate ability(166 mAh·g^(-1) at 2 A·g^(-1)).The enhanced capacity is attributed to the suitable degree of graphitization and surface area,which improve the sodium ion transport and storage.

关键词： petroleum pitch hard carbon sodium-ion batteries high rate recyclable template

Text Difficulty Study:Do Machines Behave the Same as Humans Regarding Text Difficulty?

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Machine Intelligence Research 2024年第2期21卷 283-293页

作者： Bowen Chen Xiao Ding Yi Zhao Bo Fu Tingmao Lin Bing Qin Ting Liu Research Center for Social co.puting and Information Retrieval Harbin Institute of TechnologyHarbin 150001China Fundamental Technology Center China Construction Bank Financial Technology Co.Ltd.Beijing 100033China

With the emergence of pre-trained models,current neural networks are able to give task performance that is co.parable to ***,we know little about the fundamental working mechanism of pre-trained models in which we do not know how they approach such performance and how the task is solved by the *** example,given a task,human learns from easy to hard,whereas the model learns ***,difficulty-insensitive learning leads to great success in natural language processing(NLP),but little attention has been paid to the effect of text difficulty in *** propose a human learning matching index(HLM Index)to investigate the effect of text *** results show:1)LSTM gives more human-like learning behavior than ***,UID-SuperLinear gives the best evaluation of text difficulty among four text difficulty *** nine tasks,some tasks’performance is related to text difficulty,whereas others are not.2)Model trained on easy data performs best in both easy and medium test data,whereas trained on hard data only performs well on hard test data.3)Train the model from easy to hard,leading to quicker co.vergence.

关键词： co.nition inspired natural language processing psycholinguistics explainability text difficulty curriculum learning

Fluorinated semi-interpenetrating polymer networks for enhancing the mechanical performance and storage stability of polymer-bonded explosives by co.trolling curing and phase separation rates

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Defence Technology（防务技术） 2024年第8期38卷 58-66页

作者： Chao Deng Huihui Liu Yongping Bai Zhen Hu School of Chemistry and Chemical Engineering Harbin Institute of TechnologyHarbin 150000China Wuxi HIT New Material Research Institute co. Ltd.Wuxi 214000China Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China

Herein, the effect of fluoropolymer binders on the properties of polymer-bonded explosives(PBXs) was co.prehensively investigated. To this end, fluorinated semi-interpenetrating polymer networks(semiIPNs) were prepared using different catalyst amounts(denoted as F23-CLF-30-D). The involved curing and phase separation processes were monitored using Fourier-transform infrared spectrosco.y, differential scanning calorimetry, a haze meter and a rheometer. Curing rate co.stant and activation energy were calculated using a theoretical model and numerical method, respectively. Results revealed that owing to its co.co.tinuous micro-phase separation structure, the F23-CLF-30-D3 semi-IPN exhibited co.siderably higher tensile strength and elongation at break than pure fluororubber F2314 and the F23-CLF-30-D0 semi-IPN because the phase separation and curing rates matched in the initial stage of *** arc Brazilian test revealed that F23-CLF-30-D-based co.posites used as mock materials for PBXs exhibited excellent mechanical performance and storage stability. Thus, the matched curing and phase separation rates play a crucial role during the fabrication of high-performance semi-IPNs;these factors can be feasibly co.trolled using an appropriate catalyst amount.

关键词： Semi-interpenetrating polymer networks Fluoropolymer Curing rate Phase separation rate Polymer-bonded explosives

Multi-scale modeling for prediction of mechanical performance in brazed GH99 thin-walled structure

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Chinese Journal of Aeronautics 2024年第7期37卷 550-563页

作者： Yazhou LIU Shengpeng HU Yanyu SONG Wei FU Xiaoguo SONG Ning GUO Weimin LONG State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China Shandong Institute of Shipbuilding Technology Weihai 264209China China Machinery Intelligent Equipment Innovation Research Institute(Ningbo)co. Ltd.Ningbo 315700China

Superalloy thin-walled structures are achieved mainly by brazing,but the deformation process of brazed joints is non-uniform,making it a challenging research *** paper reco.ds a thorough investigation of the effect of brazing parameters on the microstructure of joints and its mechanical properties,which mainly inquires into the deformation and fracture mechanisms in the shearing process of GH99/BNi-5a/GH99 *** macrosco.ic-microsco.ic deformation mechanism of the brazing interface during shearing was studied by Crystal Plasticity(CP)and Molecular Dynamics(MD)on the basis of the optimal brazing *** experimental results show that the brazing interface is mainly formed by(Ni,Cr,co.(s,s)and possesses a shear strength of approximately 546 *** shearing fracture of the brazed joint occurs along the brazing seam,displaying the characteristics of intergranular *** simulations show that dislocations disassociate and transform into fine twinning with increased *** simulated the shear deformation process of the brazed *** multiscale simulation results are co.sistent with the experimental *** mechanical properties of thin-walled materials for brazing are predicted using MD and CP methods.

关键词： Multi-scale modeling Brazing Shear mechanisms Crystal plasticity GH99 superalloy