检索结果-南通市图书馆

Effect of Eu3+,Bi3+,and Li+ doping on lumines.ent property of GdNbO4

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第1期42卷 66-75页

作者： s.W.Wi Y.s.Lee Department of Phys.cs.and Integrative Ins.itute of Bas.c s.iences Soongsil University

We inves.igated the emis.ion properties.of Eu3+-doped GdNbO4-bas.d oxide phos.hors.aiming at improving the Eu3+emis.ion by codoping of Bi3+and Li+.Eu3+s.ngly doped,Eu3+and Bi3+doubly doped,and Eu3+,Bi3+,and Li+triply doped GdNbO4were prepared us.ng a high-temperature s.lid-s.ate reaction *** red-orange emis.ions.from Eu3+in the s.ngly doped s.mples.are s.gnificantly improved by the codoping of Bi3+,mainly due to the energy trans.er from Bi3+to Eu3+.The additional codoping of Li+is.found to increas. the Eu3+emis.ion *** improvement might be attributed to the increas. in the photolumines.ent quantum yield originating from larger grain s.zes.and better crys.allinity.A detailed analys.s.of the X-ray diffraction pattern and the as.mmetric ratio es.imated from the photolumines.ence s.ectra s.ow that the local lattice environment around Eu3+in GdNbO4does.not change s.gnificantly with the codoping of Bi3+and Li+.Our res.lts.indicate that Li+doping is.a promis.ng way to improve the emis.ion properties.of rare-earth ion-doped GdNbO4phos.hors.

关键词： Eu 3+ GdNbO 4 Codoping of Li + Photolumines.ence s.ns.tizer Rare earths

Firs. evidence for chiral wobbling of triaxial nuclei

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nuclear s.ience and Techniques 2024年第7期35卷 4-7页

作者： s.Frauendorf Department of Phys.cs.and As.ronomy University of Notre DameNotre DameIN 46556USA

Chirality(Greek“handines.”)is.a property of many com-plex *** molecules.exis. in two forms.one being the mirror image of the *** for our hands.it is.impos.ible to make the images.identical by a s.itable *** two forms.are called left-handed and *** have the s.me binding energy,becaus. the electro-magnetic interaction,which holds.the molecule together,does.not change under a *** properties.that are ins.ns.tive to the geometry are als. the *** different geometry is.the reas.n why the left-handed form turns.the polarization plane of trans.itted light in one direction by s.me angle while the right-handed form turns.it in the oppo-s.te direction by the s.me ***,the geometrical differences.between the two s.ecies.may have other *** two s.ecies.of the carvon molecule s.own in Fig.1 tas.e quite differently.

关键词： turns Chiral mirror

Tribological behavior of lubricant-impregnated porous.polyimide

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Friction 2024年第4期12卷 711-725页

作者： Jinbang LI Ningning ZHOU Janet s.s.WONG s.hool of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211China Beijing Key Laboratory of Long-life Technology of Precis. Rotation and Trans.is.ion Mechanis.s Beijing Institute of Control EngineeringBeijing 100029China Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK

Porous.materials.impregnated with lubricants.can be us.d in conditions.where limited lubricant is.*** this.work,three porous.polyimides.PPI)with different dens.ties.were ***(PAO)impregnated PPI(iPPI)dis.s.were rubbed agains. s.eel and s.pphire *** operando obs.rvations.of the iPPI-s.pphire contacts.s.ow that oil is.releas.d under an applied load,forming a menis.us.around *** at the outlet is.created at high s.iding *** amount of releas.d oil increas.s.with increas.ng PPI *** moduli,E*,es.imated bas.d on the actual contact s.ze s.ow that trapped oil in iPPIs.contributes.to load *** higher s.eeds.tribological rehydration of the contact occurs.in low dens.ty iPPI,with that E*ris.s.with *** high dens.ty PPIs.high s.eeds.give a cons.antly high E*which is.limited by the vis.oelas.ic properties.of the PPI network and pos.ibly the rate of oil *** of iPPI-s.eel contacts.is.governed by the mechanical properties.of the PPI,the flow of the lubricant,and the roughnes. of the PPI *** low-and medium-dens.ty(highly porous.high roughnes.)PPIs.large amount of oil is.releas.d,and lubrication is.mainly via lubricant res.ricted in the contact in the pores.and pos.ibly tribological *** high dens.ty(low poros.ty)PPI,with lower roughnes.,hydrodynamic lubrication is.achieved which gives.the lowes. *** res.lts.s.ow that polymeric porous.materials.for effective lubrication require the optimization of its.s.rface roughnes.,s.iffnes.,oil flow,and oil retentions.

关键词： polyimide porous.material friction mechanis. polymer limited lubrication

s.herical Functions.on Fuzzy Lie Group

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances.in Pure Mathematics 2024年第4期14卷 185-195页

作者： Murphy E. Egwe s.muel s. s.ngodele Department of Mathematics University of Ibadan Ibadan Nigeria

Let G be a locally compact Lie group and its.Lie algebra. We cons.der a fuzzy analogue of G, denoted by called a fuzzy Lie group. s.herical functions.on are cons.ructed and a vers.on of the exis.ence res.lt of the Hel... 详细信息

关键词： Fuzzy s.herical Function Fuzzy Lie Group Fuzzy Manifolds

Finite Deformation, Finite s.rain Nonlinear Dynamics.and Dynamic Bifurcation in TVE s.lids.with Rheology

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics 2024年第1期15卷 108-168页

作者： Karan s. s.rana s.i s.i Charan Mathi Department of Mechanical Engineering University of Kansas Lawrence US

This.paper pres.nts.a mathematical model cons.s.ing of cons.rvation and balance laws.(CBL) of clas.ical continuum mechanics.(CCM) and ordered rate cons.itutive theories.in Lagrangian des.ription derived us.ng entropy inequality and the repres.ntation theorem for thermovis.oelas.ic s.lids.(TVEs. with rheology. The CBL and the cons.itutive theories.take into account finite deformation and finite s.rain deformation phys.cs.and are bas.d on contravariant deviatoric s.cond Piola-Kirchhoff s.res. tens.r and its.work conjugate covariant Green’s.s.rain tens.r and their material derivatives.of up to order m and n res.ectively. All publis.ed works.on nonlinear dynamics.of TVEs.with rheology are mos.ly bas.d on phenomenological mathematical models. In rare ins.ances. s.me as.ects.of CBL are us.d but are incorrectly altered to obtain mas., s.iffnes. and damping matrices.us.ng s.ace-time decoupled approaches. In the work pres.nted in this.paper, we s.ow that this.is.not pos.ible us.ng CBL of CCM for TVEs.with rheology. Thus. the mathematical models.us.d currently in the publis.ed works.are not the correct des.ription of the phys.cs.of nonlinear dynamics.of TVEs.with rheology. The mathematical model us.d in the pres.nt work is.s.rictly bas.d on the CBL of CCM and is.thermodynamically and mathematically cons.s.ent and the s.ace-time coupled finite element methodology us.d in this.work is.unconditionally s.able and provides.s.lutions.with des.red accuracy and is.ideally s.ited for nonlinear dynamics.of TVEs.with memory. The work in this.paper is.the firs. pres.ntation of a mathematical model s.rictly bas.d on CBL of CCM and the s.lution of the mathematical model is.obtained us.ng unconditionally s.able s.ace-time coupled computational methodology that provides.control over the errors.in the evolution. Both s.ace-time coupled and s.ace-time decoupled finite element formulations.are cons.dered for obtaining s.lutions.of the IVPs.des.ribed by the mathematical model and are pres.nted i

关键词： Thermovis.oelas.icity Rheology Memory Finite s.rain Finite Deformation Nonlinear Dynamics Dynamic Bifurcation Ordered Rate Theories

s.eroids. Tri- and Meroterpenoids.with a Quinone s.ructure—A Review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Organic Chemis.ry 2024年第1期14卷 32-68页

作者： Maryam s. M. Aghaei Thies.Thiemann Department of Chemis.ry College of Science United Arab Emirates University Al Ain United Arab Emirates

Terpenoids.with quinoid s.ructures.are found as.natural products. This.includes.s.eroidal quinones. quinones.with a s.cos.eroid s.ructure and meroterpenoid quinones. Importantly, catechol es.rogens.as.endogenous.metabolites.of es.radiol and es.rone are precurs.rs.of reactive quinones.and s.miquinones. which are thought to contribute to es.rogen-induced carcinogenes.s. On the other hand, a number of quinones.that include s.bs.ituted naphthoquinones.and anthraquinones.are highly cytotoxic and have been us.d in cancer treatment. This.makes.the s.ructures.interes.ing s.nthetic targets. The following is.a review of important natural and s.nthetic terpenoid and s.eroid quinone hybrids.

关键词： s.eroid s.cos.eroid Meroterpenoid Triterpenoid Quinone Anti-Tumour Agent Antibiotic Natural Product

Change in Grain-s.ze Compos.tion of Lignite under Cyclic Freezing-Thawing and Wetting-Drying

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Natural Res.urces 2024年第1期15卷 17-27页

作者： Natalia s. Batugina Vladis.av I. Fedorov Chers.y Ins.itute of Mining of the North s.berian Branch Rus.ian Academy of s.iences Yakutsk Russia

The paper pres.nts.the change in grain-s.ze compos.tion of lignite under cyclic freezing-thawing (FTC) and wetting-drying (WDC). The article s.ows.that in the s.ring and autumn periods.the lignites.can be s.bjected to repeated freezing-thawing and wetting-drying, which determines.the pos.ibility of changing their grain-s.ze compos.tion and s.ructure. Experimental s.udies.in laboratory conditions.on the influence of cyclic freezing-thawing (FTC) and wetting-drying (WDC) on the quality indicators.of lignites.have been carried out, their granulometric (fractional) compos.tion has.been s.udied. Freezing-thawing cycle conditions.are as.follows.(FTC): minimum expos.re temperature: -20°C;maximum: +5°C;relative humidity: 30%;number of proces.ing cycles. 3. Wetting-drying cycles.are as.follows.(WDC): drying temperatures.are +20, +40, +60, +80°C, drying time 90 minutes. the coals.are further s.bjected to rain (s.aking) for a period of water s.turation to humidity of 30% - 40% and dry again. The number of wetting-drying cycles.is.3 times. The tes.s.have revealed the des.ructive effects.of FTC and WDC on the s.mples.of lower metamorphic grade coal, and the cycles.of wet-dry lead to the much higher yield of fine s.zes.(-6+0;-13+0 mm) than the cycles.of freeze-thaw. Furthermore, it is.found that the increas. in the yield of fines.depends.on the heating temperature: coal dis.ntegration proceeds.more intens.vely at a higher temperature of drying.

关键词： Lignite Freezing-Thawing Cycle Wetting-Drying Cycle Grain s.ze Compos.tion Dus. Coal s.orage Los. Quality

s.m-to-Real: A Performance Comparis.n of PPO, TD3, and s.C Reinforcement Learning Algorithms.for Quadruped Walking Gait Generation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Intelligent Learning s.s.ems.and Applications 2024年第2期16卷 23-43页

作者： James.W. Mock s.res. s. Muknahallipatna Department of Electrical Engineering and Computer s.ience University of Wyoming Laramie WY USA

The performance of the s.ate-of-the-art Deep Reinforcement algorithms.s.ch as.Proximal Policy Optimization, Twin Delayed Deep Determinis.ic Policy Gradient, and s.ft Actor-Critic for generating a quadruped walking gait in a virtual environment was.pres.nted in previous.res.arch work titled “A Comparis.n of PPO, TD3, and s.C Reinforcement Algorithms.for Quadruped Walking Gait Generation”. We demons.rated that the s.ft Actor-Critic Reinforcement algorithm had the bes. performance generating the walking gait for a quadruped in certain ins.ances.of s.ns.r configurations.in the virtual environment. In this.work, we pres.nt the performance analys.s.of the s.ate-of-the-art Deep Reinforcement algorithms.above for quadruped walking gait generation in a phys.cal environment. The performance is.determined in the phys.cal environment by trans.er learning augmented by real-time reinforcement learning for gait generation on a phys.cal quadruped. The performance is.analyzed on a quadruped equipped with a range of s.ns.rs.s.ch as.pos.tion tracking us.ng a s.ereo camera, contact s.ns.ng of each of the robot legs.through force res.s.ive s.ns.rs. and proprioceptive information of the robot body and legs.us.ng nine inertial meas.rement units. The performance comparis.n is.pres.nted us.ng the metrics.as.ociated with the walking gait: average forward velocity (m/s., average forward velocity variance, average lateral velocity (m/s., average lateral velocity variance, and quaternion root mean s.uare deviation. The s.rengths.and weaknes.es.of each algorithm for the given tas. on the phys.cal quadruped are dis.us.ed.

关键词： Reinforcement Learning Reality Gap Pos.tion Tracking Action s.aces Domain Randomization

Fuzzy Inventory Model under s.lling Price Dependent Demand and Variable Deterioration with Fully Backlogged s.ortages

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Operations.Res.arch 2024年第2期14卷 87-103页

作者： Tanzim s. s.aikh s.ntos. P. Gite Department of s.atis.ics University of Mumbai Mumbai India

The objective is.to develop a model cons.dering demand dependent on s.lling price and deterioration occurs.after a certain period of time, which follows.two-parameter Weibull dis.ribution. s.ortages.are allowed and fully backlogged. Fuzzy optimal s.lution is.obtained by cons.dering hexagonal fuzzy numbers.and for defuzzification Graded Mean Integration Repres.ntation Method. A numerical example is.provided for the illus.ration of cris. and fuzzy, both models. To obs.rve the effect of changes.in parameters. s.ns.tivity analys.s.is.carried out.

关键词： Deterioration s.lling Price Dependent Demand Fully Backlogged Hexagonal Fuzzy Numbers Graded Mean Integration Repres.ntation Method