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Simulation of Thermocapillary Convection in a TwoLayer Immiscible Fluid System Using a Boundary Element Method

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Journal of Thermal Science 1992年第4期1卷 259-266页

作者： Wen-Qiang Lu Department of physics,Graduate School,Academia Sinica,p.o.box 3908,Beijing 100039,China Department of physics Graduate School Academia Sinica Beijing China

A boundary element method for simulating thermocapillary convection in a two-layer immiscible fluid system with flat and free interface has been *** divergence theorem is applied to the non-linear convective volume integral of the boundary element formulation with the pressure penalty ***,velocity gradients are eliminated and the complete formulation is written in terms of *** avoids the difficulty of convective discretizations and provides considerable reductions in storage and computational requirements while improving *** this paper,we give the influence of different parameters(Marangoni number, Reynolds number)on thermocapillary convection in cavity with two-layer immiscible *** shown by the numerical results,when the physical parameters between liquid encapsulant and melt are chosen appropriately, the detrimental flow in the bottom melt layer can be greatly *** influence of the free interface on thermocapillary convection is also shown.

关键词： boundary element computation of convective terms thermocapillary convection twolayer immiscible fluids in cavity flat and free interfaces

Characterizing objective and self-report habitual physical activity and sedentary time in outpatients with an acquired brain injury

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Sports Medicine and Health Science 2024年第4期6卷 338-343页

作者： Liam p.pellerine Katerina Miller Ryan J.Frayne Myles W.o'Brien Division of Kinesiology School of Health and Human PerformanceFaculty of HealthDalhousie UniversityHalifaxNova ScotiaCanada Acquired Brain Injury NeuroCommons Nova Scotia Health AuthorityHalifaxNova ScotiaCanada School of physiotherapy(Faculty of Health)&Department of Medicine(Faculty of Medicine) Dalhousie UniversityHalifaxNova ScotiaCanada Geriatric Medicine Research Dalhousie University&Nova Scotia HealthHalifaxNova ScotiaCanada Centre de Formation Medicale Du Nouveau-Brunswick New Brunswick&Department of MedicineUniversite de SherbrookeSherbrookeQuebecCanada

outpatients with an acquired brain injury(ABI)experience physical,mental,and social *** can be classified into two subgroups based on mechanism of injury:mild traumatic brain injury(mTBI;e.g.,concussion)and other ABI(e.g.,stroke,brain aneurysm,encephalitis).our understanding of habitual activity levels within ABI populations is limited because they are often collected using self-report *** purpose of this study was to,1)describe the habitual activity levels of outpatients with ABI using objective and self-report monitoring,and 2)compare the activity levels of outpatients with mTBI *** *** outpatients with other ABI(mean±standard deviation:[58±13]years,9 females)and 12 outpatients with mTBI([48±11]years,9 females)wore a thigh-worn activpAL 24 h/day(h/day)for *** with ABI averaged(6.0±2.3)h/day of upright time,(10.6±2.2)h/day of sedentary time,(5.6±2.7)h/day in prolonged sedentary bouts>1 h,(5960±3037)steps/day,and(11±13)minutes/day(min/day)of moderate-vigorous physical activity(MVpA).There were no differences between activpAL-derived upright,sedentary,prolonged sedentary time,and physical activity between the mTBI and other ABI groups(all,p>0.31).outpatients with ABI overestimated their MVpA levels(t138 min/week)and underestimated sedentary time(-4.3 h/day)compared to self-report(all,ppite self-reporting high activity levels,outpatients with ABI objectively exhibit highly inactive and sedentary *** habitual movement behaviours of our sample did not differ by mechanism of injury(i.e.,mTBI versus other ABI).Targeting reductions in objectively measured sedentary time are needed to progressively improve the habitual movement behaviours of outpatients with ABI.

关键词： Accelerometry Stroke Brain aneurysm Encephalitis Mild traumatic brain injury Rehabilitation

Emission properties of Yb^(3+)/Er^(3+) Doped Teo_2-Wo_3-Zno Glasses for Broadband optical Amplifiers

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Journal of Materials Science & Technology 2004年第2期20卷 139-142页

作者： Jiacheng Lp, Shunguang LI, Hefang HU and Fuxi GANShanghai Institute of optics and Fine Mechanics, Chinese Academy of Sciences, p.o.box 800-211, Shanghai 201800, China Inst. of optics and Fine Mech. Chinese Acad. of Sci. P.O. Box 800-211 Shanghai 201800 China

The Yb3+/Er3+ doped Teo2-Wo3-Zno glasses were prepared. The absorption spectra, emission spectra and fluorescence lifetime of Er3+ at 1.5 um, excited by 970 nm were measured. The influence of Er2o3, Yb2o3 and oH-contents on emission properties of Er3+ at 1.5μm was investigated. The optimum doping concentrations for Er3+ and Yb3+ is around 3.34×1020 ions/cm3 and 6.63×1020 ions/cm3, respectively. The peak emission cross section is 0.83~0.87 pm2. With the increasing concentration of Yb3+, the FWHM of Er3+ emission at 1.5μm in the glass increases from 77 nm to 83 nm. The results show that Yb3+/Er3+ doped Teo2-Wo3-Zno glasses are promising candidate for Er3+-doped broadband optical amplifier.

关键词： Tungsten-tellurite glass Yb3+/Er3+ doping Emission properties

A synthetic microbial community used as a bioinoculant can overcome rice production constraints in acid soils

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Science China(Life Sciences) 2024年第5期67卷 1085-1086页

作者： Maureen o’Callaghan Shengjing Shi Resilient Agriculture Group AgResearchLincolnChristcurch 8140New Zealand

A customised synthetic microbial community(SynCom)composed of carefully selected rhizosphere-competent bacterial strains improved rice growth,yield and resistance to soil acidity and Al toxicity.

关键词： soil soils rhizosphere

Valorization of Tree Bark-Derived Suberin in Applications for the Bio-Based Composites Industry–A Recent Review

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Journal of Renewable Materials 2024年第6期12卷 1029-1042页

作者： Aleksandra Jeżo Institute of Wood Sciences and Furniture SGGWNowoursynowska St.159Warsaw02-776Poland

Bark extracts are sustainable sources of biopolymers and hold great promise for replacing fossil fuel-based polymers,for example,in wood-based *** addition to primary and secondary metabolites,tree bark also contains suberin,which plays a major role in protecting the tree from environmental *** is a natural aliphatic-aromatic cross-linked polyester present in the cell walls of both normal and damaged external tissues,the main component of which are long-chain aliphatic *** main role as a plant ingredient is to protect against microbiological factors and water *** of the most important suberin monomers are suberin fatty acids,known for their hydrophobic and barrier ***,due to the diverse chemical composition of suberin,it is an attractive alternative to hydrocarbon-based *** its potential is recognized,it is not widely used in biocomposites technology,including wood-based composites and the polymer *** article will discuss the current knowledge about the potential of suberin and its components in biocomposites technology,which will include surface finishes,composite adhesives and polymer blends.

关键词： Suberin suberinic acids wood composites biocomposites biopolyester

A New Design Method for the octave-Band Stripline Circulators

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Journal of Systems Engineering and Electronics 1994年第4期5卷 33-39页

作者： pan YongjiBeijing Institute of Radio Measurement, p.o.box 3923, Beijing 100854, China Beijing Institute of Radio Measurement P.O. Box 3923 Beijing 100854 China

In this paper, a new design method for high performance octave-band stripline circulator is given. The optimum design program is given by a construction with double-Y junction aided by a section of quarter-wavelength impedance transformer. All the calculation is simpler than that given by Y. S. Wu, et al[1-7]. Typical performances of the 2-4GHz Y-junction stripline circulator are insertion loss 0.35dB (max), isolation 21dB (min), VSWR 1.25 (max). An octave low-loss and high isolation performance is demonstrated without the need of repeated design cycles.

关键词： octave-band stripline circulator Double Y Junction.

preparation of Strontium Bismuth Tantalum (SBT) Fine powder by Sol-Gel process Using Bismuth Subnitrate as Bismuth Source

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Journal of Materials Science & Technology 2001年第1期17卷 25-26页

作者： Wen WANG Yu ZHoU Sheng CHEN Feng YE and Dechang JIA School of Materials Science and Engineering, p.o.box 433, Harbin institute of Technology, Harbin 150001, China Sch. of Mater. Sci. Harbin Inst. of Technol. P.O. Box 433 Harbin 150001 China

Strontium bismuth tantalum (SBT) fine power was prepared by Sol-Gel method. pentaethoxy tantalum, strontium acetate and bismuth subnitrate were used as raw materials, and were dissolved in proper order in ethylene glycol to form transparent sol. The mixed precursor was dried at 80℃ and annealed at 800℃ for 1 h. Crystallized nanometer sized SBT fine powder was obtained and characterized by XRD.

关键词： SBT preparation of Strontium Bismuth Tantalum Ta Fine powder by Sol-Gel process Using Bismuth Subnitrate as Bismuth Source

Aerodynamic Sweeping Study and Design for Transonic Compressor Rotor blades

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Journal of Thermal Science 2010年第4期19卷 295-299页

作者： N.X.Chen,H.W.Zhang and W.G Huang Institute of Engineering Thermophysics,Chinese Academy of Sciences p.o.box 2706 Beijing,100080,China Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China

The objective of the present paper is to study the sweep effect on the blade design performance of a transonic compressor *** baseline to be modified and swept is a designed well efficient transonic single rotor compressor. The first part of the present study is concerning the sweep effect with straight leading *** this case fixing the hub section the swept blade is formed by tilting the leading edge with whole blade forwards and backwards *** second part is to use an optimization strategy with simple gradient-based optimum-searching method and multi-section blade parameterization technique to search and generate an optimal swept rotor with curved arbitrary leading *** adiabatic efficiency is a little bit greater than that of the reference un-swept rotor.

关键词： Aerodynamic optimization blade sweep transonic compressor rotor

Enhanced entropy generation and heat transfer characteristics of magnetic nano-encapsulated phase change materials in latent heat thermal energy storage systems

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1051-1070页

作者： p.S.REDDY p.SREEDEVI Department of Mathematics Rajeev Gandhi Memorial College of Engineering and TechnologyNandyal 518501India

The objective of the current study is to investigate the importance of entropy generation and thermal radiation on the patterns of velocity,isentropic lines,and temperature contours within a thermal energy storage device filled with magnetic nanoencapsulated phase change materials(NEpCMs).The versatile finite element method(FEM)is implemented to numerically solve the governing *** effects of various parameters,including the viscosity parameter,ranging from 1 to 3,the thermal conductivity parameter,ranging from 1 to 3,the Rayleigh parameter,ranging from 102 to 3×10^(2),the radiation number,ranging from 0.1 to 0.5,the fusion temperature,ranging from 1.0 to 1.2,the volume fraction of NEpCMs,ranging from 2%to 6%,the Stefan number,ranging from 1 to 5,the magnetic number,ranging from 0.1 to 0.5,and the irreversibility parameter,ranging from 0.1 to 0.5,are examined in detail on the temperature contours,isentropic lines,heat capacity ratio,and velocity ***,the heat transfer rates at both the cold and hot walls are analyzed,and the findings are presented *** results indicate that the time taken by the NEpCMs to transition from solid to liquid is prolonged inside the chamber region as the fusion temperatureθf ***,the contours of the heat capacity ratio Cr decrease with the increase in the Stefan number Ste.

关键词： volume fraction of nano-encapsulated phase change material(NEpCM) radiation Stefan number heat capacity ratio entropy generation