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Simulation of lubrication on rough surfaces with multiscale lubrication neural networks

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Science China Technological Sciences 2025年第3期68卷 196-207页

作者： Yihu TANG Li HUANG Limin WU Xianghui MENG School of mechanical engineering Shanghai Jiao Tong University national Key laboratory of Marine Engine Science and Technology Shanghai Marine Diesel research Institute

The simulation of lubrication on rough surfaces is essential for the design and optimization of tribological performance. Although the application of physics-informed neural networks(PINNs) in analyzing hydrodynamic lubrication has been increasing, their implementation has predominantly been restricted to smooth surfaces. This limitation arises from the inherent spectral bias of conventional PINN methodologies, which tend to prioritize the learning of low-frequency features,thereby hindering their ability to analyze rough surfaces characterized by high-frequency signals effectively. To date, there have been no reported instances of PINN methodologies being applied to rough surface lubrication. In response to these challenges,this paper presents an innovative multiscale lubrication neural network(MLNN) architecture that incorporates a trainable Fourier feature embedding. By integrating learnable feature embedding frequencies, this architecture is capable of automatically adjusting to various frequency components, thus improving the analysis of rough surface characteristics. The proposed method has been evaluated across a range of surface topographies, with results compared to those derived from the finite element method(FEM). The comparative analysis indicates a high degree of consistency between the MLNN results and those obtained through FEM. Moreover, this novel architecture demonstrates superior performance in terms of both accuracy and computational efficiency when compared to traditional Fourier feature networks that utilize fixed feature embedding frequencies. As a result, the MLNN model represents a more effective tool for the analysis of lubrication on rough surfaces.

关键词： physics-informed neural network Fourier feature embedding multiscale lubrication rough surface

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Unveiling the photocatalytic marvels:Recent advances in solar heterojunctions for environmental remediation and energy harvesting

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Journal of Environmental Sciences 2025年第2期148卷 283-297页

作者： Najmeh Askari Mansoureh Jamalzadeh Aghil Askari Naiyun Liu Bijan Samali Mika Sillanpaa Leigh Sheppard Haitao Li Raf Dewil Department of Chemical engineering Process and Environmental Technology LabKU LeuvenDe Nayerlaan 5 Sint-Katelijne-Waver2860Belgium Department of Plastics engineering UMass LowellLowellMA 01851USA Department of mechanical engineering UMass LowellLowellMA 01851USA Institute for Energy research Jiangsu UniversityZhenjiang 212013China Centre for Infrastructure engineering Western Sydney UniversityPenrith NSW2751Australia Department of Biological and Chemical engineering Aarhus UniversityGustav Wieds Vej 108000 AarhusDenmark Solar Energy Technologies research Group Western Sydney UniversityPenrith NSW2751Australia Department of engineering Science University of OxfordParks RoadOxfordOX13PJUnited Kingdom

In the quest for effective solutions to address *** meet the escalating energy demands,heterojunction photocatalysts have emerged as a captivating and versatile *** photocatalysts have garnered significant interest due to their wideranging applications,including wastewater treatment,air purification,CO_(2) capture,and hydrogen generation via water *** technique harnesses the power of semiconductors,which are activated under light illumination,providing the necessary energy for catalytic *** visible light constituting a substantial portion(46%)of the solar spectrum,the development of visible-light-driven semiconductors has become *** photocatalysts offer a promising strategy to overcome the limitations associated with activating semiconductors under visible *** this comprehensive review,we present the recent advancements in the field of photocatalytic degradation of contaminants across diverse media,as well as the remarkable progress made in renewable energy ***,we delve into the crucial role played by various operating parameters in influencing the photocatalytic performance of heterojunction ***,we address emerging challenges and propose novel perspectives to provide valuable insights for future advancements in this dynamic research *** unraveling the potential of heterojunction photocatalysts,this reviewcontributes to the broader understanding of their applications and paves the way for exciting avenues of exploration and innovation.

关键词： Heterojunction photocatalysts Solar photocatalysis Environmental depollution Energy conversion Visible-light-driven semiconductors

Cutting force modeling in high-speed machining of selective laser melted Ti6Al4V alloys based on a modified constitutive model considering thermally activated effect

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Science China Technological Sciences 2025年第3期68卷 142-159页

作者： Dejian LIU Chenbing NI Youqiang WANG Lida ZHU Zhongpeng ZHENG Wei LU Naixin ZHANG Xingbao HUANG School of mechanical and Automotive engineering Qingdao University of Technology Key lab of Industrial Fluid Energy Conservation and Pollution Control Ministry of Education School of mechanical engineering and Automation Northeastern University School of mechanical engineering Tsinghua University Shandong Zhongheng Jingxin Carbon Fiber Technology Development Co. Ltd State Key laboratory of Bridge Safety and Resilience College of Civil Engineering Hunan University

The thermally activated effect can produce a vital influence on the mechanical property and cutting force of metal materials in the machining process. An insight can be gained into the action criteria of the thermally activated effect on the cutting force, which provides a solid basis of the research of material performance and machinability. In this study, a cutting force model of selective laser melted(SLMed) Ti6Al4V alloy is proposed by introducing the modified constitutive model with thermally activated effects and the analytical model of the deformation zone into the cutting force model. The anisotropic properties of SLMed Ti6Al4V alloy under different scanning strategies(0°, 67.5°, and 90°) are explored by combining with the cutting force model, constitutive model and analytical model of deformation zone(primary deformation and tool-chip contact area). The action of thermally activated effects on the cutting force, primary deformation and tool-chip contact zone is also researched in detail. Milling experiments and predictions of SLMed Ti6Al4V alloy under different scanning strategies have been implemented to reveal the effectiveness of this new model. The comparison results indicate that the proposed milling force model can effectively predict milling force and reflect well on the anisotropy of SLMed Ti6Al4V *** addition, this proposed force model can well analyze the action mechanism of the thermally activated effect on the milling force of SLMed Ti6Al4V alloy, which is significantly essential for the machining mechanism research in terms of a microscopic perspective.

关键词： cutting force model modified constitutive model thermally activated effect SLMed Ti6Al4V alloy laser scanning strategies anisotropic properties

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Revealing and predicting the long-term biomechanical response of orthokeratology by developing a patient-specific computational model

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Science China(Physics,Mechanics & Astronomy) 2025年第1期68卷 152-164页

作者： Yifeng Li Zhuoran Yang Ziming Yan Huibin Shi Zhanli Liu Kaijie Wang Department of engineering Mechanics School of Aerospace EngineeringTsinghua UniversityBeijing 100084China Beijing Tongren Eye Center Beijing Tongren HospitalCapital Medical UniversityBeijing Ophthalmology&Visual Sciences Key LabBeijing 100730China

Orthokeratology(OK)is widely used for effective myopia correction and ***,the incomplete understanding of its biomechanical mechanisms makes OK lens fitting rely heavily on clinician judgment,complicating accurate predictions of treatment *** this paper,we performed clinical experiments and numerical analysis to study corneal deformation modes and long-term changes in central corneal *** experiments were conducted on 194 Chinese myopic patients under OK treatment for 3 *** on the experimental data,a patient-specific computational biomechanical model for OK was established and ***,the anisotropic mechanical properties of the cornea were incorporated into the model to describe the significant difference between its shear modulus(29.5 kPa)and tensile modulus(768.4 kPa).Additionally,a viscohyperelastic material model with a prolonged corneal relaxation time of 5.6 h was developed to capture the long-term deformation *** results show that corneal thickness reduction in OK is primarily due to out-of-plane shear deformation,influenced by the cornea’s low shear *** the extended corneal relaxation time is crucial for predicting long-term biomechanical *** computational model effectively captures long-term changes in central corneal thickness,potentially improving OK lens fitting accuracy.

关键词： orthokeratology computational biomechanical model long-term viscoelasticity myopia correction

High-Magnetic-Field-Induced First-Order Magnetic Transition and Tricritical Phenomenon in Antiferromagnetic Semimetal NdSb

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Chinese Physics Letters 2025年第2期42卷 125-131页

作者： Jun Zhao Azizur Rahman Wei Liu Langsheng Ling Yuyan Han Chuanying Xi Li Pi Zhe Qu Hao Gao Lei Zhang School of mechanical and Electrical engineering Sanming UniversitySanming 365004China Anhui Key laboratory of Low-Energy Quantum Materials and Devices High Magnetic Field LaboratoryHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China Department of Physics Lab of Low-dimensional Magnetism and Spintronic DevicesSchool of PhysicsHefei University of TechnologyHefei 230009China Institutes of Physical Science and Information Technology Anhui UniversityHefei 230601China Hefei national research Center for Physical Sciences at Microscale University of Science and Technology of ChinaHefei 230026China

The antiferromagnetic(AFM)semimetal NdSb is well known for the interplay between its exotic magnetism and topological ***,its magnetism remains poorly *** this study,we thoroughly investigated the magnetization of NdSb single crystals with a high magnetic field(H)of up to 30T applied in various *** found that the AFM phase is suppressed by a magnetic field of 9.41T when H‖[100]and 11.25T when H‖[110],whereas the suppression field ranges from 9.41 to 10.67T with a hysteresis of 1.26T when H‖[111].The magnetization of H‖[100],which is an easy direction with a typical magnetic transition,was studied in *** AFM phase with H‖[100]was suppressed at lower temperatures,disappearing at approximately 6.25 *** critical exponents β=0.234(3),γ=0.824(6),and δ=4.90(6)were obtained for H‖[100],and aligned with a tricritical mean-field *** of the critical behavior suggests a fieldinduced tricritical phenomenon for H‖[100].An H-T phase diagram for an NdSb single crystal was constructed for H‖[100],revealing a field-induced first-order transition and a tricritical point(TCP)at T_(tr)=6.25K and H_(tr)=9.41 *** clarification of the multiple magnetic phases and transitions in NdSb provides crucial insights into the correlation between its magnetism and topology.

关键词： critical magnetization Transition

Supplementary Material to‘High-magnetic-Field-induced frst-order magnetictransition and tricritical phenomenon in antiferromagnetic semimetal NdSb’

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Chinese Physics Letters 2025年第2期42卷 132-134页

作者： Jun Zhao Azizur Rahman Wei Liu Langsheng Ling Yuyan Han Chuanying Xi Li Pi Zhe Qu Hao Gao Lei Zhang School of mechanical and Electrical engineering Sanming UniversitySanming 365004China Anhui Key laboratory of Low-Energy Quantum Materials and Devices High Magnetic Field LaboratoryHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China Department of Physics Lab of Low-dimensional Magnetism and Spintronic DevicesSchool of PhysicsHefei University of TechnologyHefei 230009China Institutes of Physical Science and Information Technology Anhui UniversityHefei230601China Hefei national research Center for Physical Sciences at Microscale University of Science and Technology of ChinaHefei 230026China

Ⅰ.SAMPLE *** erystals of NdSb were synthesized by an In-fhux *** purity chemical elements of Nd(99.9% purity,Alfa Aesar),8b(99.999%,Aladdin),and In beads(99.99%,Aladdin)were thoroughly mixed in a glove-box filledwith... 详细信息

关键词： method. purity magnetic

An analytical solution for the stress field and stress intensity factor in an infinite plane containing an elliptical hole with two unequal aligned cracks

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Applied Mathematics and Mechanics(English Edition) 2018年第8期39卷 1103-1118页

作者： M.HAJIMOHAMADI R.GHAJAR mechanical Properties research lab (MPRL) Faculty of Mechanical Engineering K.N. Toosi University of Technology

The existing analytical solutions are extended to obtain the stress fields and the stress intensity factors(SIFs) of two unequal aligned cracks emanating from an elliptical hole in an infinite isotropic plane. A conformal mapping is proposed and combined with the complex variable method. Due to some difficulties in the calculation of the stress function, the mapping function is approximated and simplified via the applications of the series expansion. To validate the obtained solution, several examples are analyzed with the proposed method, the finite element method, etc. In addition, the effects of the lengths of the cracks and the ratio of the semi-axes of the elliptical hole(a/b) on the SIFs are studied. The results show that the present analytical solution is applicable to the SIFs for small cracks.

关键词： complex variable conformal mapping unequal crack elliptical hole stress intensity factor(SIF)

A mechanical reinforced and antifreezing polyacrylate hydrogel electrolyte for high-performance zinc-ion batteries

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Nano research 2025年第1期18卷 341-350页

作者： Zili Zhang Ruolin Wang Hongfei Lu Di Zhang Yu Zhao Jing Xu Bin Sun Zhi-Min Dang Yang Jin School of Electrical and Information engineering Zheng Zhou UniversityZhengzhou 450001China State Key lab of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

The operation of aqueous zinc-ion batteries in flexible energy storage field is plagued by the uncontrollable growth of Zn-dendrite and inevitable freeze of water below 0 ℃.Therefore,it is necessary to design a hydrogel electrolyte with good mechanical property and freezing resistance to uniform the Zn-deposition and resist flexibility loss at low *** find that the mechanical property(strength and toughness)of hydrogel electrolyte has a significant impact on the suppression of dendrite growth and the uniform deposition of zinc ***,a polyacrylate hydrogel is prepared in one step by ultraviolet(UV)curing method with Zn(CF_(3)SO_(3))_(2)salt and polyvinyl alcohol(PVA)addition to increase the antifreezing ability and mechanical *** adsorption of water molecules by 2-hydroxyethyl acrylate(HEA)and PVA reduces the freezing point of the hydrogel,which is beneficial for enhancing the electrochemical stability at low *** this basis,the Zn-symmetrical battery with hydrogel electrolyte has a long lifespan of 4710 h at 0.5 mA·cm^(-2)and 0.5 mAh·cm^(-2)at room ***,the hydrogel electrolyte exhibits an outstanding stability at low temperature of^(-2)0 ℃,the lifespan of symmetrical battery reaches to 4000 h at 0.5 mA·cm^(-2)and 0.5 mAh·cm^(-2).The assembled full cell with NaV3O8·1.5H_(2)O(NVO)cathode and hydrogel electrolyte possesses a high capacity retention ratio of 77%after 10,000 cycles at^(-2)0 ℃.The flexible cell can power light-emitting diode(LED)lamp under bending,warping and cutting without liquid leakage and an electronic watch at the operating temperature of^(-2)0 ℃.

关键词： zinc ion battery hydrogel electrolyte mechanical enhancement freezing resistance

Impacts of continuously regenerating trap and particle oxidation catalyst on the NO_2 and particulate matter emissions emitted from diesel engine

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Journal of Environmental Sciences 2012年第4期24卷 624-631页

作者： Zhihua Liu Yunshan Ge Jianwei Tan Chao He Asad Naeem Shah Yan Ding LinxiaoYu Wei Zhao national lab of Auto Performance and Emission Test School of Mechanical and Vehicular EngineeringBeijing Institute of TechnologyBeijing 100081China Department of mechanical engineering University of Engineering and TechnologyLahore 54000Pakistan Chinese research Academy of Environmental Sciences Beijing 100012China

Two continuously regenerating diesel particulate filter （CRDPF） with different configurations and one particles oxidation catalyst （POC） were employed to perform experiments in a controlled laboratory setting to evaluate their effects on NO2, smoke and particle number emissions. The results showed that the application of the after-treatments increased the emission ratios of NO2/NOx significantly. The results of smoke emissions and particle number （PN） emissions indicated that both CRDPFs had sufficient capacity to remove more than 90% of total particulate matter （PM） and more than 97% of solid particles. However, the POC was able to remove the organic components of total PM, and only partially to remove the carbonaceous particles with size less than 30 nm. The negligible effects of POC on larger particles were observed due to its honeycomb structure leads to an inadequate residence time to oxidize the solid particles or trap them. The particles removal efficiencies of CRDPFs had high degree of correlations with the emission ratio of NO2/NOx. The PN emission results from two CRDPFs indicated that more NO2 generating in diesel oxidation catalyst section could obtain the higher removal efficiency of solid particles. However this also increased the risk of NO2 exposure in atmosphere.

关键词： continuously regenerating diesel particulate filter particles oxidation catalyst particle number diesel engine size distribution