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Tailored surface textures to increase friction-A review

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Friction 2022年第9期10卷 1285-1304页

作者： Henara l.COSTA jörg SCHIllE Andreas ROSENKRANZ School of Engineering Surface Engineering GroupUniversidade Federal do Rio GrandeRio Grande 96203900Brazil University of Applied Sciences Mittweida Laserinstitut Hochschule Mittweida 09648Germany Department of Chemical Engineering Biotechnology and MaterialsUniversity of ChileSantiago 8370459Chile

Surface textures with micro-scale feature dimensions still hold great potential to enhance the frictional performance of tribological *** from the ability of surface texturing to reduce friction,surface textures can also be used to intentionally increase friction in various applications that rely on friction for their adequate ***,this review aims at presenting the state-of-the-art regarding textured surfaces for high-friction *** a brief general introduction,the recent trends and future paths in laser surface texturing are ***,the potential of surface textures to increase friction in different applications including adhesion,movement transmission and control,biomimetic applications,and road-tire contacts is critically *** emphasis in this section is laid on the involved mechanisms responsible for friction ***,current short-comings and future research directions are pointed out thus emphasizing the great potential of(laser-based)surface texturing methods for innovations in modern surface engineering.

关键词： surface texturing tribology laser processing friction increase

Coercivity mechanisms in nanostructured permanent magnets

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Chinese Physics B 2019年第7期28卷 1-13页

作者： G P Zhao l Zhao l C Shen j Zou l Qiu College of Physics and Electronic Engineering & Institute of Solid State Physics Sichuan Normal UniversityChengdu 610066 China State Key luboratory of Metastablc Materials Science and Technology Yunshnn University.Qinhuangdao 066004China Collaborative Innovation Center for Shunxi Advanced Permanent Materials and Technology Lint'en 041004 China

Coercivity mechanism in permanent magnets has been debated for many *** this paper, various models of the coercivity mechanism are classified and re-examined by the comparison and *** rotation and curling models can reveal the underlying reversal mechanism clearly based on isolated grains with elliptic *** contrast, the numerical methods consider inter-grain interactions while simulating the evolution of the spins and hysteresis loops with complicated ***, an exact simulation of magnetic reversal in permanent nanomagnets requires many meshes to mimic the thin domain wall *** and pinning are the two main coercivity mechanisms in permanent *** former signifies the beginning of the magnetic reversal, whilst the latter completes ***, it is proposed that the large difference between the intrinsic magnetic properties of the nucleation centers and those of the main phase can result in a large pinning field(self-pinning), which has the attributes of both traditional nucleation and *** a pinning explains the experimental data of permanent magnets very well, including the enhancement of the coercivity by the grain boundary pinning.

关键词： coercivity mechanism permanent nanomagnets self-pinning

Conservation laws for energy and momentum in curved spaces

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journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第4期8卷 665-668页

作者： lóPEZ-BONIllA j. MORAlES j. OVANDO G. Section of Postgraduate Studies and Research Superior School of Mechanical and Electrical EngineeringNational Polytechnic InstituteCP 07738Mexico Division of Basic Sciences and Engineering Autonomous Metropolitan UniversityCP 02200Mexico

In arbitrary Riemannian 4-spaces, continuity equations are constructed which could be interpreted as conservation laws for the energy and momentum of the gravitational field. Special attention is given to general relativity to obtain, of natural manner, the pseudotensors of Einstein, landau-lifshitz, Moeller, Goldberg and Stachel, and also the conservation equations of Komar, Trautman, DuPlessis and Moss.

关键词： Noether theorem lagrangians in curved spaces Energy and momentum in Riemannian spaces Rund-lovelock identities

Colloidal(Gd0.98Nd0.02)2O3 nanothermometers operating in a cell culture medium within the first and second biological windows

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journal of Rare Earths 2020年第5期38卷 483-491页

作者： M.l.Debasu H.Oliveira j.Rocha l.D.Carlos Department of Physics CICECO-Aveiro Institute of MaterilsUniversidade de Aveiro3810-193AveiroPortugal Department of Chemistry CICECO-Aveiro Institute of MaterialsUniversidade de Aveiro3810-193AveiroPortugal Department of Biology CESAMLaboratory of Biotechnology and CytomicsUniversidade de Aveiro3810-193AveiroPortugal

Non-contact,self-referenced and near-infrared luminescent nanothermometers have been recognized as emerging tools in the fields of nanomedicine and nanotechnology due to their great capability of precise temperature readout at the nanoscale and real-time deep-tissue ***,the development of multifunctional and biocompatible luminescent nanothermometers operating within the optically transparent biological windows with high thermal sensitivity(>2.0%/K)remains ***,we present(Gd0.98Nd0.02)2O3 nanothermometers operated effectively within the first and second biological windows upon continuous-wave laser diode excitation at 808 *** thermometric parameters are defined by the relative changes in the emission intensities originating from the two Stark components of the 4 F3/2 level(R2 and R1)to the 4 I9/2(900-1000 nm),4 I11/2(1035-1155 nm)and 4 I13/2(1300-1450 nm)*** thermo metric parameters are evaluated for colloidal samples in a cell culture medium and powder samples,and the highest thermal sensitivity(2.18%/K at 298 K)is attained for the former in the first biological window(both the excitation and emission in the 800-965 nm range).The repeatability and temperature uncertainty are 99%and 1.2 K,*** nanothermometers are biocompatible with human MNT-1 melanoma and HaCaT cells for 24 h of exposure and nanoparticle concentration up to 0.400 mg/ml,showing their potential for applications in nanomedicine,e.g.,intracellular imaging and temperature mapping.

关键词： Gd2O3 Nd3^+-doped nanoparticles luminescent nanothermometry Thermal sensitivity Cytotoxicity of nanoparticles Rare earths

ON CERTAIN ClASS OF MEROMORPHIC FUNCTIONS WITH POSITIVE COEFFICIENTS

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Acta Mathematica Scientia 2012年第4期32卷 1376-1390页

作者： j.Dziok G.Murugusundaramoorthy j.Sokól Department of Mathematics Institute of MathematicsUniversity of Rzeszówul.Rejtana 16A35-310 RzeszówPoland School of Advanced Sciences VIT UniversityVellore-632014India Department of Mathematics Rzeszów University of Technologyul.W.Pola 235-959 RzeszówPoland

In the present investigation we define a new class of meromorphic functions on the punctured unit disk A△^＊：= {z ∈ C ： 0 〈｜z｜〈 1} by making use of the generalized Dziok-Srivastava operator Hm^l [α1]. Coefficient inequalities, growth and distortion inequalities, as well as closure results are obtained. We also establish some results concerning the partial sums of meromorphic functions and neighborhood results for functions in new class.

关键词： meromorphic functions starlike function convolution positive coefficients coefficient inequalities Dziok-Srivastava operator

Optimal distribution of active piezoelectric elements for noise attenuation in sandwich panels

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International journal of Smart and Nano Materials 2020年第4期11卷 400-416页

作者： j.F.A.Madeira A.l.Araujo IDMEC Instituto Superior TecnicoUniversidade de LisboaLisboaPortugal ADM ISELInstituto Politecnico de LisboaLisboaPortugal

In this paper,a multiobjective optimization approach for obtaining the optimal distribution of surface-bonded piezoelectric sensors and actua-tors for noise attenuation in sandwich panels is *** noise attenuation is achieved by using negative velocity feedback control with co-located sensors and *** control gains are also optimized in order to obtain the most efficient noise attenuation in a given frequency *** in-house implementation of a viscoelastic soft core sandwich plate finite element,including surface-bonded piezoelectric sensors and actuators with active control capabilities,is used for obtaining the frequency response of the *** sound transmission capability of the panels is evaluated using the radiated sound power,along with the Rayleigh integral approach,which is suitable for lightly coupled structural/acoustic *** Direct MultiSearch(DMS)optimization algorithm is used to minimize the added weight due to the piezoelectric material,minimizing also the number of required controllers and maximizing the noise *** total length of the radiated sound power curve is shown to be an effective measure of noise attenuation in a given frequency ***-off Pareto fronts and the obtained optimal configurations are presented and discussed.

关键词： Sandwich structures piezoelectricity viscoelasticity active damping multiobjective optimization

ON A ClASS OF ANAlYTIC FUNCTIONS RElATED TO CONIC DOMAINS AND ASSOCIATED WITH CARlSON-SHAFFER OPERATOR

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Acta Mathematica Scientia 2012年第4期32卷 1399-1407页

作者： S.Hussain j.Sokól Mathematics Department COMSATS Institute of Information TechnologyAbbottabadPakistan Department of Mathematics Rzeszów University of Technologyul.W.Pola 235-959 RzeszówPoland

Making use of the Carlson-Shaffer convolution operator, we introduce and study a new class of analytic functions related to conic domains. The main object of this paper is to investigate inclusion relations, coefficient bound for this class. We also show that this class is closed under convolution with a convex function. Some applications are also discussed.

关键词： Hadamard product (or convolution) differential subordination Carlson-Shaffer operator k-starlike functions k-uniformly convex function

Properties of Co_2FeAl Heusler Alloy Nano-particles Synthesized by Coprecipitation and Thermal Deoxidization Method

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journal of Materials Science & Technology 2013年第3期29卷 245-248页

作者： j.H.Du Y.l.Zuo Z.Wang j.H.Ma l.Xi Key laboratory for Magnetism and Magnetic Materials of Ministry of Education Lanzhou University

Co2FeAl nanoparticles were synthesized by reducing the coprecipitated precursor of COCl2·6H2O, Fe（NO3）3·9H2O and AI2（SO4）3·18H2O under H2 atmosphere with various annealing temperatures and durations. X-ray diffraction and transmission electron microscopy were used to characterize the crystal structure and microstructure of Co2FeAl particles, respectively. The investigation indicates that the crystal structure of CO2FeAI particles tends to be B2 structure, in which atoms are partially ordered. The saturation magnetization and hyperfine field of CO2FeAI particles, which were measured under a vibrating sample magnetometer and a 57Fe Mossbauer spectroscope, are consistent with those of the bulk sample and thin films. Furthermore, the higher annealing temperature and the longer annealing time, the better crystallinity of CO2FeAI and more ordered arrangement of atoms will be. It turned out that the coprecipitation thermal deoxidization method could be an easy and high efficient way to obtain the half-metallic CO2FeAI nanoparticles.

关键词： Heusler alloy Coprecipitation Magnetic property

Aero-Acoustics of Modern Transonic Fans—— Fan Noise Reduction from Its Sources

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journal of Thermal Science 2003年第2期12卷 104-113页

作者： l.Xu j.D.Denton Whittle laboratory University of CambridgeUKWhittle LaboratoryUniversity of CambridgeUK

The noise of aerodynamics nature from modern transonic fan is examined from its sources with the perspective of noise reduction through aero-acoustics design using advanced Computational Fluid Dynamics (CFD) tools. In particular the problems associated with the forward propagating noise in the front is addressed. It is identified that the shock wave spillage from the leading edge near the fan tip is the main source of the tone noise. Two different approaches have been studied to reduce the forward arc tone noise and two state-of-art transonic fans are designed using the strategies developed. The following rig tests show that while the fans exhibit other noise problems, the primary goals of noise reduction have been achieved through both fans and the novel noise reduction concept vindicated.

关键词： transonic fan aero-acoustics noise reduction.