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Effects of Rare Earth Elements on the Characteristics of Low Temperature Plasma Nitrocarburized martensitic Stainless Steel

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Journal of materials Science & Technology 2012年第11期28卷 1046-1052页

作者： R.L.Lju Y.J.Qiao m.f.Yan Y.d.fu College of materials Science and Chemical Engineering Harbin Engineering UniversityHarbin 150001China School of materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Low temperature plasma nitrocarburizing of 17-4PH martensitic stainless steel was conducted at 430 ℃ with and without rare earth （RE） addition. The microstructure, kinetics, microhardness, wear behavior as well as corrosion resistance of the modified layer were studied by optical microscopy, X-ray diffraction, Vickers microhardness tester, pin-on-disc tribometer and potentiodynamic polarization tests. The results show that the thickness of plasma RE nitrocarburized layer is much thicker than that formed by nitrocarburizing without RE addition. The incorporation of RE does not change the kind of the phases and the nitrocarburized layer consists mainly of nitrogen and carbon expanded martensite （aN）, γ-fe4N and a-fe with a trace of CrN phases. The surface microhardness of plasma nitrocarburized layer can be increased by 100 HV after RE addition. Wear resistance of the specimen can be apparently improved by low temperature plasma nitrocarburizing with and without RE addition and without sacrificing its corrosion resistance. Wear reduction effect of low temperature plasma nitrocarburizing with RE addition is better than that of the conventional one.

关键词： Stainless steel Low temperature Plasma nitrocarburizing Rare earth (RE) Wear and friction

Can Quick Release Experiments Reveal the muscle Structure？ A Bionic Approach

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Journal of Bionic Engineering 2012年第2期9卷 211-223页

作者： d. f. B. Haeufle m. Gunther R. Blickhan S. Schmitt Institute of Sports and Exercise-Science University of Stuttgart Allmandring 28 D-70569 Stuttgart Germany Stuttgart Research Centre for Simulation Technology （SRC SimTech） University of Stuttgart Pfaffenwaldring 7a D-70569 Stuttgart Germany Institute of motion Science Friedrich-Schiller-University Seidelstraβe 20 D-07749 Jena Germany

The goal of this study was to understand the macroscopic mechanical structure and function of biological muscle with respect to its dynamic role in the contraction. A recently published muscle model, deriving the hyperbolic force-velocity relation from first-order mechanical principles, predicts different force-velocity operating points for different load situations. With a new approach, this model could be simplified and thus, transferred into a numerical simulation and a hardware experiment. Two types of quick release experiments were performed in simulation and with the hardware setup, which represent two extreme cases of the contraction dynamics： against a constant force （isotonic） and against an inertial mass. Both experiments revealed hyperbolic or hyperbolic-like force-velocity relations. Interestingly, the analytical model not only predicts these extreme cases, but also additionally all contraction states in between. It was possible to validate these predictions with the numerical model and the hardware experiment. These results prove that the origin of the hyperbolic force-velocity relation can be mechanically explained on a macroscopic level by the dynamical interaction of three mechanical elements. The implications for the interpretation of biological muscle experiments and the realization of muscle-like bionic actuators are discussed.

关键词： force-velocity relation isotonic quick release proof of concept artificial muscle

New features of the Pulsar B0950+08 Radiation at the frequency of 111 mHz

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Research in Astronomy and Astrophysics 2022年第3期22卷 88-99页

作者： V.m.malofeev I.f.malov O.I.malov d.A.Teplykh P.N.Lebedev Physical Institute of the Russian Academy of Sciences Leninskii pr.53Moscow119991Russia

Results of long time observations of the pulsar B0950+08 are *** observations were carried out at the LPA radio telescope at the frequency of 111 mHz from January of 2016 to may of 2019(450 days).A strong variability in emission of this pulsar has been detected with changes in signal to noise ratios hundreds of *** of the long-time flux density variability can be explained by refractive scintillations in the interstellar *** existence of radiation between the interpulse(IP)and main pulse(mP)was *** was more powerful than at high *** detected the unusual IP and precursor(Pr)radiation on 2017 August *** the basis of 65 strong IPs we found the correlations between energies of IP and Pr and between the phase of IP and the distance Pr–*** is shown that the observed peculiarities of this pulsar can be explained in the frame of the aligned rotator *** estimated distances of radiation levels from the center of the neutron *** calculated value of the initial period of 0.2 s means that not all pulsars are born with millisecond *** large age of the pulsar(6.8 million years)and the small angle between its magnetic moment and the rotation axis(less than 20°)confirm the suggestion related to pulsar evolution with respect to alignment.

关键词： (stars:)pulsars:individual(PST B0950+08) radiation mechanisms:general (stars:)pulsars:general

mixed convection in the heated semi-circular lid-driven cavity for non-Newtonian power-law fluids: Effect of presence and shape of the block

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Chinese Journal of Chemical Engineering 2020年第5期28卷 1225-1240页

作者： Krunal m.Gangawane Hakan f.Oztop department of Chemical Engineering National Institute of Technology RourkelaRourkela 769008OdishaIndia department of mechanical Engineering Engineering FacultyFirat UniversityElazig TR-23119Turkey

The present work delineates the hydrodynamics and thermal characteristics due to mixed convection in the liddriven semi-circular cavity affected by the presence of the adiabatic block at its geometric center for twodimensional,steady-state,laminar and for non-Newtonian power-law *** semi-circular cavity has a diameter of *** horizontal wall/lid is sliding with a uniform horizontal velocity(u=U)and is subjugated to the ambient thermal condition;while the curved surface is subjugated to a higher isothermal *** convective characteristics inside the system is explored for the broad range of Richardson number(0.1≤Ri≤10),Prandtl number(1≤Pr≤100)and non-Newtonian power-law index(0.5≤n≤1.5)at a constant Grashof number of 10~*** from this,the effect of shape(cross-section)of the inserted block,i.e.,circular,square and triangular on heat transfer characteristics has also been *** is observed that the shear thickening fluids display better cooling ***,the cavity with immersed triangular block shows better heat transfer results than the circular and square *** deviations observed in the flow and heat transfer characteristics in the cavity by inserting an adiabatic block as compared with cavity without block have been ascertained by calculating normalized Nusselt number(Nu^N).The presence of the block was found to have a diminishing effect on the heat transfer due to convection in the *** the end,the results of the study are summarized in the form of a predictive correlation exhibiting the functional dependence of average Nusselt number with Prandtl number,power-law index,and Richardson number.

关键词： Heat transfer enhancement Semi-circular cavity Adiabatic block Non-Newtonian fluids

modelling two-layer nanofluid flow in a micro-channel with electro-osmotic effects by means of Buongiorno’s model

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Applied mathematics and mechanics(English Edition) 2020年第1期41卷 83-104页

作者： m.d.K.NIAZI Hang XU State Key Lab of Ocean Engineering Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE)School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong University

A fully developed steady immiscible flow of nanofluid in a two-layer microchannel is studied in the presence of electro-kinetic ***’s model is employed for describing the behavior of *** from the previous studies on two-layer channel flow of a nanofluid,the present paper introduces the flux conservation conditions for the nanoparticle volume fraction field,which makes this work new and unique,and it is in coincidence with practical *** governing equations are reduced into a group of ordinary differential equations via appropriate similarity *** highly accurate analytical approximations are *** physical quantities and total entropy generation are analyzed and discussed.A comparison is made to determine the significance of electrical double layer(EdL)effects in the presence of an external electric *** is found that the Brownian diffusion,the thermophoresis diffusion,and the viscosity have significant effects on altering the flow behaviors.

关键词： electrical double layer(EdL) entropy generation micro-channel nanofluid

Tissue engineering approaches for dental pulp regeneration:The development of novel bioactive materials using pharmacological epigenetic inhibitors

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Bioactive materials 2024年第10期40卷 182-211页

作者： Ross m.Quigley michaela Kearney Oran d.Kennedy Henry f.duncan division of Restorative dentistry&Periodontology Dublin Dental University HospitalTrinity College Dublin(TCD)University of DublinLincoln PlaceDublinIreland department of Anatomy and Regenerative medicine and Tissue Engineering Research GroupRoyal College of Surgeons in Ireland(RCSI)University of Medicine and Health SciencesDublinIreland The Trinity Centre for Biomedical Engineering(TCBE)and the Advanced materials and Bioengineering Research Centre(AmBER) Royal College of Surgeons in Ireland(RCSI)and Trinity College Dublin(TCD)DublinIreland

The drive for minimally invasive endodontic treatment strategies has shifted focus from technically complex and destructive root canal treatments towards more conservative vital pulp ***,novel approaches to maintaining dental pulp vitality after disease or trauma will require the development of innovative,biologicallydriven regenerative medicine *** example,cell-homing and cell-based therapies have recently been developed in vitro and trialled in preclinical models to study dental pulp *** approaches utilise natural and synthetic scaffolds that can deliver a range of bioactive pharmacological epigenetic modulators(HdACis,dNmTis,and ncRNAs),which are cost-effective and easily applied to stimulate pulp tissue ***,many biological factors hinder the clinical development of regenerative therapies,including a lack of blood supply and poor infection control in the necrotic root canal *** challenges include a need for clinically relevant models and manufacturing challenges such as scalability,cost concerns,and regulatory *** review will describe the current state of bioactive-biomaterial/scaffold-based engineering strategies to stimulate dentine-pulp regeneration,explicitly focusing on epigenetic modulators and therapeutic pharmacological *** will highlight the components of dental pulp regenerative approaches,describe their current limitations,and offer suggestions for the effective translation of novel epigenetic-laden bioactive materials for innovative therapeutics.

关键词： Epigenetics Regenerative medicine Regenerative endodontics Biocompatible materials Tissue engineering

NUmERICAL SImULATION ANd EXPERImENT Of CAVITY GROWTH dURING SUPERPLASTIC BULGING Of mAGNESIUm ALLOY ZK60

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Acta metallurgica Sinica(English Letters) 2004年第3期17卷 295-298页

作者： Y.d.Yu K.f.Zhang H.R.Zheng d.m.Jiang department of materials Engineering Harbin Institute of Technology Harbin 150001 ChinaDepartment of Materials Engineering Harbin Institute of Technology Harbin 150001 ChinaDepartment of Materials Engineering Harbin Institute of Technology Harbin 150001 ChinaDepartment of Materials Engineering Harbin Institute of Technology Harbin 150001 China

Numerical simulation and experimental studies on cavity growth were carreed out dur-ing the bulging process of saperplastic magnesium Alloy. A three--dimensional rigid-viscoplastic finite element program has been developed and applied to predict the cav-ity radiusand volume fraction of cavity growth. The final prediction on the cavityradius and volume fraction distribution was exhibited as colorful shade pictures. Theexperimental studies wereperformed under similar conditions to the numerical oneand provided for quantitativecomparison. According to the metallography observation,the radius and volume fraction of cavity growth was quantitative achieved by usingProfound--Iron & steel software. The numerical results were in reasonable quantita-tive agreement with the experiment.

关键词： magnesium alloy cavity numerical simulation saperplastic bulging

Effect of Y^(3+), Gd^(3+) and La^(3+) dopant ions on structural, optical and electrical properties of o-mullite nanoparticles

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Journal of Rare Earths 2014年第1期32卷 37-42页

作者： m.m.S.Sanad m.m.Rashad E.A.Abdel-Aal m.f.El-Shahat K.Powers Central metallurgical R & d Institute Particle Engineering Research Center University of Florida faculty of Science Ain Shams University

dielectric ceramics of m（x）Al6（1-x）Si2O13 doped mullite were synthesized via co-precipitation technique. The X-ray diffrac-tion profiles revealed that these nanoparticles were crystallized well and the volume of mullite unit cell was increased as a function of the ionic radius of dopant ion. TEm images showed regular orthorhombic crystal morphology for the pure mullite sample. meanwhile, the doped samples exhibited slightly distorted crystal morphology of larger particle sizes. dSC thermograms evinced that the exo-thermic peak temperature of mullite was shifted to the lower value with m3＋ion insertion. The photoluminescence spectra were stud-ied for mullite samples, and it was found that the intensity of the emission spectra was affected by the m3＋ion type. It was found that, Y3＋doped mullite achieved the minimum dielectric loss value of 0.01 in the radio wave frequency region （1 mHz）. meanwhile, Gd3＋doped mullite achieved the minimum dielectric loss value of 0.09 in the microwave frequency region （1 GHz）.

关键词： rare earths doped mullite photoluminescence crystallization temperature dielectric ceramics

Preliminary performance analysis and optimization based on 1d neutronics model for Indian dEmO HCCB blanket

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Plasma Science and Technology 2020年第8期22卷 184-191页

作者： d AGGARWAL C dANANI m Z YOUSSEf Institute for Plasma Research GandhinagarGujarat 382428India homi Bhabha National Institute(HBNI) AnushaktinagarMumbai 400094India University of California-Los Angeles Los AngelesCA 90095United States of America

India,under its breeding blanket R&d program for dEmO,is focusing on the development of two tritium breeding blanket concepts;namely the lead-lithium-cooled ceramic breeder and the helium-cooled ceramic breeder(HCCB).The study presented in this paper focuses on the neutronic design analysis and optimization from the tritium breeding perspective of the HCCB *** Indian concept has an edge-on configuration and is one of the variants of the helium-cooled solid breeder blanket concepts proposed by several partner countries in *** Indian HCCB blanket having lithium titanate(Li2TiO3)as the tritium breeder and beryllium(Be)as the neutron multiplier with reduced-activation ferritic/martensitic steel structure aims at utilizing the low-energy neutrons at the rear part of the *** aim of the optimization study is to minimize the radial blanket thickness while ensuring tritium self-sufficiency and provide data for further neutronic design and thermal-hydraulic layout of the HCCB *** is found that inboard and outboard blanket thicknesses of 40 cm and 60 cm,respectively,can give a tritium breeding ratio(TBR)>1.3,with 60%6Li enrichment,which is assumed to be sufficient to cover potential tritium losses and associated *** results also demonstrated that the Be packing fraction(Pf)has a more profound impact on the TBR as compared to 6Li enrichment and the Pf of Li2TiO3.

关键词： dEmO helium-cooled ceramic breeder blanket neutronic optimization study tritium breeding ratio