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Grain size effect on the assembly quality of micro-scaled barrel formed by microforming

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Advances in manufacturing 2024年第1期12卷 19-32页

作者： Dien Hu Jieyichen Fang Feng Zeng ming-Wang fu Department of Mechanical Engineering Research Institute of Advanced ManufacturingThe Hong Kong Polytechnic UniversityHung HomKowloonHong KongPeople’s Republic of China Xiamen Yulong machinery Co.Ltd. Xiamen361023FujianPeople’s Republic of China

In this research,a method employing micro-extrusion was designed to produce the micro-scaled barrel-shaped parts with complex geometrical features to study the feasibility of the proposed microforming method and its grain size effect on the formability of the complicated internal features in terms of deformation behavior,material evolution,accuracy of dimensions and final components *** results reveal that the deformation behavior is highly affected by grain size and becomes unpredictable with increased grain *** addition,assembly parameters including feature dimension,tolerance and coaxiality also vary with grain size,and the variation of grain size needs to be accommodated by different assembly types,viz.,clearance fit or transition *** the microstructural evolution aspect,it was identified there were two dead zones and four shear bands,and the formation of these deformation zones was barely affected by the variation in grain *** bulges,cracks,and fracture induced voids were observed on the surface of the final components,tailoring the microstructure of the working material with finer grains could significantly avoid these *** study advances the understanding of forming microparts by extrusion processes and provides guidance for microforming of similar microparts.

关键词： Microformed part Size effect Extrusion Microstructural evolution Dimensions Assembly accuracy

Electronic structure regulation and built-in electric field synergistically strengthen photocatalytic nitrogen fixation performance on Ti-BiOBr/TiO_(2)heterostructure

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Rare Metals 2024年第3期43卷 1125-1138页

作者： Ru-Qi Li Yu-Jie Bian Chun-ming Yang Li Guo Tao-Xia ma Chuan-Tao Wang Feng fu Dan-Jun Wang College of Chemistry and Chemical Engineering Yan’an UniversityYan’an Key Laboratory of Green Catalysis and Quality Improvement and Utilization of Low Rank CoalYan’an716000China

At present,industrial synthetic ammonia was still obtained through the Hubble-Bosch process,with large energy *** is a research hotspot to realize green synthetic ammonia by using solar *** difficulty of photocatalytic ammonia synthesis was that the photo-excited electrons have not enough energy to active N≡*** this study,Ti was doped into BiOBr by one-step hydrothermal method,which was oxidized into TiO_(2)when the doping amount reaches the maximum,in situ forming Ti_(0.31)B_(0.69)OB/TiO_(2)*** from the synergistic effect of Ti doping and S-scheme heterojunction,the synthetic ammonia efficiency of Ti_(0.31)B_(0.69)OB/TiO_(2)-11.96 reached 1.643 mmol·g_(cat)^(-1)at mild conditions and without hole scavenger for up to 7 h,the efficiency of synthetic ammonia is 115 times,10.5 times and 3.3 times of that of BiOBr,Ti_(0.31)B_(0.69)OB and TiO_(2),***,DFT calculation confirms that Ti doping accurately refine the electronic structure of BiOBr,facilitate nitrogen adsorption activation and reduce hydrogenation reaction energy barrier,thus accelerating the reaction kinetics of photocatalytic nitrogen reduction(NRR),Meanwhile,constructing S-scheme heterojunction boosts the separation and transfer of photogenerated electron-hole pairs,improving the reduction ability of electrons in the conduction band of TiO_(2)and the oxidation ability of holes in the valence band of Ti_(0.31)B_(0.69)OB.

关键词： S-scheme heterostructure Electronic structure regulation Built-in electric field Synergistical stren4gthening Photocatalytic nitrogen fixation

Deciphering and integrating invariants for neural operator learning with various physical mechanisms

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National Science Review 2024年第4期11卷 111-122页

作者： Rui Zhang Qi Meng Zhi-ming ma Academy of mathematics and Systems Science Chinese Academy of Sciences(CAS) Microsoft Research

Neural operators have been explored as surrogate models for simulating physical systems to overcome the limitations of traditional partial differential equation(PDE) solvers. However, most existing operator learning methods assume that the data originate from a single physical mechanism, limiting their applicability and performance in more realistic scenarios. To this end, we propose the physical invariant attention neural operator(PIANO) to decipher and integrate the physical invariants for operator learning from the PDE series with various physical mechanisms. PIANO employs self-supervised learning to extract physical knowledge and attention mechanisms to integrate them into dynamic convolutional *** to existing techniques, PIANO can reduce the relative error by 13.6%–82.2% on PDE forecasting tasks across varying coefficients, forces or boundary conditions. Additionally, varied downstream tasks reveal that the PI embeddings deciphered by PIANO align well with the underlying invariants in the PDE systems, verifying the physical significance of PIANO.

关键词： neural operator PDE solver contrastive learning physical invariants

NUMERICAL COMPUTATION OF BOUNDED SOLUTIONS FORA SEMILINEAR ELLIPTIC EQUATION ON AN INFINITE STRIP

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Journal of Computational mathematics 1999年第2期17卷 159-170页

作者： fu-ming ma(Department of mathematics, Jilin ’University, Changchun 130023, China) 吉林大学数学系吉林长春

In this paper, we consider the computation of bounded solutions of a semilinear elliptic equation on an infinite strip. The dynamical system approach and reduction on center manifold are used to overcome the difficult... 详细信息

关键词： numerical method nonlinear PDE center manifold

Gyroid Triply Periodic Minimal Surface Lattice Structure Enables Improved Superelasticity of CuAlMn Shape Memory Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第6期37卷 1047-1065页

作者： Mengwei Wu Chunmei ma Ruiping Liu Huadong fu Department of materials Science and Engineering China University of Mining and Technology(Beijing)Beijing100083China Institute for Advanced materials and Technology University of Science and Technology BeijingBeijing100083China

Improving the shape memory effect and superelasticity of Cu-based shape memory alloys(Smas)has always been a research hotspot in many *** work systematically investigates the effects of Gyroid triply periodic minimal surface(TPMS)lattice structures with different unit sizes and volume fractions on the manufacturing viability,compressive mechanical response,superelasticity and heating recovery properties of CuAlMn *** results show that the increased specific surface area of the lattice structure leads to increased powder adhesion,making the manufacturability proportional to the unit size and volume *** compressive response of the CuAlMn Smas Gyroid TPMS lattice structure is negatively correlated with the unit size and positively correlated with the volume *** superelastic recovery of all CuAlMn Smas with Gyroid TPMS lattice structures is within 5%when the cyclic cumulative strain is set to be 10%.The lattice structure shows the maximum superelasticity when the unit size is 3.00 mm and the volume fraction is 12%,and after heating recovery,the total recovery strain increases as the volume fraction *** study introduces a new strategy to enhance the superelastic properties and expand the applications of CuAlMn Smas in soft robotics,medical equipment,aerospace and other fields.

关键词： Shape memory alloys Superelasticity Gyroid triply periodic minimal surface(TPMS)lattice structure Selective laser melting(SLM)

The flow behavior of droplet adsorption on a liquid-liquid interface accompanied by cross-linking reaction and phase separation in a microchannel

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Chinese Journal of Chemical Engineering 2024年第2期66卷 60-70页

作者： Haozhe Yi Taotao fu Chunying Zhu Youguang ma State Key Laboratory of Chemical Engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

The adsorption process of droplets on the liquid-liquid interface and phase separation process can regulate the spatial distribution of the fluid system,which are crucial for chemical ***,the cross-linking reaction,which is widely used in the field of polymers,can change the physical properties of the fluids and affect the flow behavior accordingly.A configuration of microchannels is designed to conveniently generate uniform droplets in one phase of the parallel *** flow behavior of the adsorption process of sodium alginate droplets on the liquid-liquid interface is investigated,and the subsequent process of phase separation is *** the process of droplet adsorption,the crosslinking reaction occurs synchronously,which makes the droplet viscosity and the elasticity modules of the droplet surface increase,thus affecting the dynamics of the adsorption process and the equilibrium shape of the *** variation of the adsorption length with time is divided into three stages,which all conform to power law *** exponents of the second and third stages deviate from the results of the Tanner's *** flow pattern maps of droplet adsorption and phase separation are drawn,and the operating ranges of complete adsorption and complete separation are *** study provides a theoretical basis for further studying the flow behavior of droplets with cross-linking reaction in a microchannel.

关键词： Microfluidics Droplet Dynamics Crosslink Adsorption Separation

Numerical simulation of granular silicon growth and silicon fines formation process in polysilicon fluidized bed

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Particuology 2024年第4期87卷 74-86页

作者： Guangkai Gu Guoqiang Lv Wenhui ma Shanlin Du Boqiang fu Faculty of Metallurgical and Energy Engineering Kunming University of Science and TechnologyKunming 650093China State Key Laboratory of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province Kunming 650093China

Operating conditions strongly affect the yield and quality of polysilicon in a polysilicon fluidized *** this study,a new model of polysilicon fluidized bed was established using the Euler-Euler model coupled with population balance model(PBM),which was combined with fluid flow,heat,and mass transfer models,while considering the scavenging effect of silicon *** effects of different operating conditions on the deposition and formation rates of silicon fines were *** show that the model can correctly describe the particle growth process in the fluidized bed of *** silicon fines and the interphase velocity difference show"N"-and"M"-shaped distributions along the axial direction,*** particle temperature and concentration near the wall are higher than those in the central *** decomposition of silane in the bottom region of the bed is dominated by het-erogeneous *** scavenging of silicon fines occurs in the dilute-phase *** effects of operating conditions,*** gas temperature,silane composition,and gas velocity,on the reactor performance were also explored *** the inlet gas composition and velocity enhances the formation rates of solid silicon and *** the inlet gas temperature promotes the growth of solid silicon and inhibits the formation of silicon *** fluidization ratio,low inlet silane concentration,and high inlet gas temperature enhance the selectivity of silicon growth.

关键词： Polysilicon fluidized bed Particle growth Fines CFD Population balance model(PBM)

machine learning-assisted efficient design of Cu-based shape memory alloy with specific phase transition temperature

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International Journal of Minerals,Metallurgy and materials 2024年第4期31卷 773-785页

作者： Mengwei Wu Wei Yong Cunqin fu Chunmei ma Ruiping Liu Department of materials Science and Engineering China University of Mining&Technology(Beijing)Beijing 100083China Institute for Advanced materials and Technology University of Science and Technology BeijingBeijing 100083China

The martensitic transformation temperature is the basis for the application of shape memory alloys(Smas),and the ability to quickly and accurately predict the transformation temperature of Smas has very important practical *** this work,machine learning(ML)methods were utilized to accelerate the search for shape memory alloys with targeted properties(phase transition temperature).A group of component data was selected to design shape memory alloys using reverse design method from numerous unexplored *** modeling and feature modeling were used to predict the phase transition temperature of the shape memory *** experimental results of the shape memory alloys were obtained to verify the effectiveness of the support vector regression(SVR)*** results show that the machine learning model can obtain target materials more efficiently and pertinently,and realize the accurate and rapid design of shape memory alloys with specific target phase transition *** this basis,the relationship between phase transition temperature and material descriptors is analyzed,and it is proved that the key factors affecting the phase transition temperature of shape memory alloys are based on the strength of the bond energy between *** work provides new ideas for the controllable design and performance optimization of Cu-based shape memory alloys.

关键词： machine learning support vector regression shape memory alloys martensitic transformation temperature

Efficacy of Huoxue Qianyang Qutan Recipe on essential hypertension:A randomized,double-blind,placebo-controlled trial

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Journal of Integrative Medicine 2024年第4期22卷 484-492页

作者： Jun Xie Yu-long ma ming-tai Gui Lei Yao Jian-hua Li ming-zhu Wang Xun-jie Zhou Yi-fan Wang ming-yi Zhao Hui Cao Bo Lu De-yu fu Department of Cardiology Yueyang Hospital of Integrated Traditional Chinese and Western MedicineShanghai University of Traditional Chinese MedicineShanghai 200437China Shanghai University of Traditional Chinese Medicine Shanghai 200120China

Background:Hypertension,a prevalent disease,is a significant risk factor for coronary heart *** Qianyang Qutan Recipe (HQQR),a traditional Chinese herbal remedy,has been used for treating hypertension over several ***:This study assesses HQQR’s efficacy for controlling blood pressure among patients with hypertension related to blood stasis,yang hyperactivity and ***,setting,participants and interventions:A randomized controlled trial was conducted at the Yueyang Hospital of Integrated Traditional Chinese and Western Medicine,Shanghai University of Traditional Chinese Medicine,China,from July 2020 to June *** components of HQQR were identified using thin-layer chromatography and high-performance liquid *** aged18–80 years,exhibiting traditional Chinese medicine syndromes of blood stasis,yang hyperactivity or phlegm,along with grades 1 or 2 hypertension,were randomly categorized into two *** intervention group was given HQQR granules alongside conventional hypertension treatment,while the control group was given placebo granules in addition to conventional treatment for 12 *** outcome measures:The primary outcome was clinic blood pressure,whereas secondary outcomes included metabolic indices (e.g.,homeostasis model assessment of insulin resistance[HOma-IR],total cholesterol[TC],low-density lipoprotein cholesterol and triglyceride),target organ damage indices (left ventricular mass index and urinary albumin creatinine ratio[UACR]) and inflammation indices(interleukin-6[IL-6]and high-sensitivity C-reactive protein[hs-CRP]).Results:HQQR’s primary components were identified as salvianolic acid B,emodin and ferulic *** the 216 participants (108 in each group),compared to the control,the intervention group exhibited significant improvements (P<0.001) in clinic systolic blood pressure ([136.24±7.63]vs[130.06±8.50]mmHg),clinic diastolic blood pressure ([84.34±8.72]vs[80.46±6.05]mmHg),home systol

关键词： Huoxue Qianyang Qutan Recipe Hypertension Target organ damage Glycolipid metabolism Inflammatory Chinese herbal compound