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Rheological fluid motion in tube by metachronal waves of cilia

Applied Mathematics and Mechanics(English Edition) 2017年第3期38卷 393-410页

作者： s.MAITI s.K.PANDEY Department of Mathematical sciences Indian Institute of Technology (BHU) Department of Mathematics The LNM Institute of Information Technology

This paper presents a theoretical study of a non-linear rheological fluid transport in an axisymmetric tube by cilia. An attempt has been made to explain the role of cilia motion in the transport of fluid through the ductus efferent of the male reproductive tract. The Ostwald-de Waele power-law viscous fluid is considered to represent the rheological fluid. We analyze pumping by means of a sequence of cilia beats from rowto-row of cilia in a given row of cells and from one row of cells to the next(metachronal wave movement). For this purpose, we consider the conditions that the corresponding Reynolds number is small enough for inertial effects to be negligible, and the wavelengthto-diameter ratio is large enough so that the pressure can be considered uniform over the cross section. Analyses and computations of the fluid motion reveal that the time-average flow rate depends on ε, a non-dimensional measure involving the mean radius a of the tube and the cilia length. Thus, the flow rate significantly varies with the cilia ***, the flow rate has been reported to be close to the estimated value 6 × 10ml/h for human efferent ducts if ε is near 0.4. The estimated value was suggested by Lardner and shack(Lardner, T. J. and shack, W. J. Cilia transport. Bulletin of Mathematical Biology, 34, 325–335(1972)) for human based on the experimental observations of flow rates in efferent ducts of other animals, e.g., rat, ram, and bull. In addition, the nature of the rheological fluid, i.e., the value of the fluid index n strongly influences various flow-governed characteristics. An interesting feature of this paper is that the pumping improves the thickening behavior for small values of ε or in free pumping(?P = 0) and pumping(?P > 0) regions.

关键词： non-Newtonian fluid cilia movement metachronal wave volumetric flow flow reversal velocity at wave crest and trough

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POLYMER sCAFFOLDs BEARING AZOBENZENE-POTENTIAL FOR OPTICAL INFORMATION sTORAGE

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Chinese Journal of Polymer science 2001年第2期19卷 147-153页

作者： sφren Hvilsted P.s.Ramanujam Danish Polymer Centre Chemical Engineering Department Technical University of Denmark DK-2800 Kgs. Lyngby DenmarkOptics and Fluid Dynamics Department Risφ National LaboratoryDK-4000 Roskilde Denmark

The fundamental optical storage mechanism of the laser light eddressable azobenzene moiety is briefly introduced.A modular and flexible synthesis design furnishes polyester matrices covalently integrating cyanoazobenzene in regularlyspaced side chains. Thin films of these materials are particularly well suited for holographic storape. Notable figures of meritsof liquid crystalline polyesters are response time to blue-green laser light of the order of nanoseconds, storage capacityexpressed as 5000 lines/mm, and high, permanent (almost nine years) diffraction efficiency of the order of 50% or greater,and erasability, The implications of the main chain nature for polyester morphology and for the permanency of the inducedanisotropy are discussed, The design and methods of preparation of other significantly different polymer scaffolds supportingcyanoazobenzene are elaborated. Oligopeptides always result in amorphous materials, whereas copolymethacrylates anddendritic or hyperbranched polyesters provide some materials that exhibit liquid crystallinity. However, none of these scaffolds affords materials that result in permanent anisotropy when exposed to interfering laser light.

关键词： Azobenzene side-chain polymers Copolymethacrylates Dendrimers Holographic storage LC and amorphous polyesters Morphology Oligopeptides

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Experimental study on microstructural and corrosion behaviors of friction stir processed steel with CoCrFeCuTi HEA reinforcement and effect of annealing

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science China Technological sciences 2025年第1期 233-250页

作者： s.Aravind KRIsHNA N.RADHIKA Alokesh PRAMANIK N.JEYAPRAKAsH Department of Mechanical Engineering Amrita School of EngineeringAmrita Vishwa Vidyapeetham school of Civil and Mechanical Engineering Curtin University school of Mechanical and Electrical Engineering China University of Mining and Technology

The ability to perform against extreme corrosion environments in stainless steel depreciates under challenging conditions in industrial applications. This can be resolved by employing surface modification techniques to modify the surface with the required characteristics. The present study investigates the outcomes of friction stir processing of ss304 with CoCrFeCuTi high entropy alloy(HEA) as reinforcement and the property enhancements post-annealing. The synthesized CoCrFeCuTi HEA exhibited irregular fragments with 17 μm mean particle size and body centred cubic(BCC) phase. The microstructure of the processed surface revealed ultra-refined grains with a uniform distribution of HEA filler. The microstructures of the samples annealed at 400℃, 550℃, 700℃ and 850℃ for 2 h also showed significant grain growth and grain refinements. The processed sample with HEA reinforcement annealed at 700℃ exhibited enhanced microhardness and tensile strength by 63% and 0.88 times than that of the processed sample with HEA pre-annealing. The subsequent electrochemical corrosion test displayed better corrosion resistance for the HEA-processed and annealed sample. Hot corrosion tests at 900℃ showcased excellent resistance for the HEA processed and annealed samples by 14.92%, 12.75%, and 14.83% against the samples pre-annealed under three different salt mixtures, and the corroded surface was analyzed.

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The 3,4-dimethoxybenzyl group as solubilizing protective group for the in situ deprotection/deposition of extended aromatic thiolate monolayers

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Nano Research 2023年第1期16卷 1695-1702页

作者： Adrian Wiesner sonja Katzbach Dariusz Bebej Martina Dettenhöfer Michael Zharnikov Andreas Terfort Institut für Anorganische und Analytische Chemie Johann Wolfgang Goethe Universität FrankfurtMax-von-Laue-Straße 7Frankfurt am Main D-60438Germany Angewandte Physikalische Chemie Universität HeidelbergIm Neuenheimer Feld 253Heidelberg D-69120Germany

While self-assembled monolayers(sAMs)of aromatic thiolates are frequently used in a wide range of applications,their formation is often hampered by the low solubilities of their *** we introduce the 3,4-dimethoxybenzyl group as a protective group for the thiol moiety,which increases the solubility and stability of the precursor,but becomes cleaved off during monolayer formation,especially at elevated temperature(60°C)and in presence of protons(trifluoroacetic acid).For a series of substituted terphenylthiols as model systems,it could be demonstrated by using ellipsometry,infrared-reflection absorption spectroscopy,and scanning-tunneling microscopy that the resulting sAMs have the same structure and quality as the ones obtained from the respective unprotected *** protective group has the additional advantage to be stable under Pdcatalyzed C–C bond formation reaction conditions,facilitating the syntheses of the respective precursors.

关键词： self-assembled monolayers protective group solubility scanning-tunneling microscopy infrared-reflection absorption spectroscopy

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Peristaltic flow of a heated Jeffrey fluid inside an elliptic duct:streamline analysis

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Applied Mathematics and Mechanics(English Edition) 2021年第4期42卷 583-592页

作者： s.NADEEM s.AKHTAR A.sALEEM Department of Mathematics Quaid-i-Azam University 45320Islamabad 44000Pakistan Department of Anatomy School of DentistryShaheed Zulfiqar Ali Bhutto Medical UniversityIslamabad 44000Pakistan

The peristaltic flow of a heated Jeffrey fluid inside a duct with an elliptic cross-section is studied.A thorough heat transfer mechanism is interpreted by analyzing the viscous effects in the energy *** governing mathematical equations give dimensionless partial differential equations after *** final simplified form of the mathematical equations is evaluated with respect to the relevant boundary conditions,and the exact solution is *** results are further illustrated by graphs,and the distinct aspects of peristaltic flow phenomena are discussed.

关键词： peristalsis elliptic duct Jeffrey fluid streamline

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Effect of Dy-substitution on structural and magnetic properties of Mn-Zn ferrite nanoparticles

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Journal of Rare Earths 2018年第1期36卷 86-94页

作者： K.V.Zipare s.s.Bandgar G.s.shahane Department of Electronics DBF Dayanand College of Arts and Science

This paper describes the structural and magnetic properties of Dy-substituted Mn-Zn ferrite nano- particles. Mn-Zn-Dy ferrite nanopafficles of the composition ***204 （x- 0.05, 0.1, 0.15 and 0.2） were synthesized by a facile chemical co-precipitation method. The samples were characterized through X-ray diffraction （XRD）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FTIR）, vibrating sample magnetometer （VsM） and Curie temperature. The XRD patterns confirm the synthesis of single crystalline phase of Mn-Zn-Dy ferrite nanoparticles. Lattice parameter increases with increase in Dy-substitution which confirms the replacement of Fe3＋ ions by Dy3＋ ions. Crystallite size is of the order of 6-8 nm for all these samples. The particle sizes observed from TEM analysis are in good agreement with the XRD values. The magnetic measurements show super- paramagnetic nature of the samples. The saturation magnetization decreases with increase in Dy- concentration and can be correlated to modifications in the A-B exchange interactions as a result of the structural modifications due to Dy-substitution. The Curie temperature for ***204 nano- particles is 124 ℃ and decreases up to 84 ℃with the increase in the Dy-concentration. The decrease in Curie temperature can be attributed to the weakening of the superexchange interaction between A-site and B-site as a result of Dy-substitution. The low value of Curie temperature and higher value of ther- momagnetic coefficient kT shown by these samples makes them suitable for the preparation of tem- perature sensitive ferrofiuid for heat transfer applications.

关键词： Mn-Zn-Dy ferritesstructural characterizationMagnetic propertiesCurie temperatureRare earths

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EVOLUTIONARY CHARACTERIsTICs OF LAKEs AND PALAEOCLIMATIC UNDULATION IN THE Q AID AM BAsIN,CHINA

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Chinese Journal of Oceanology and Limnology 1993年第1期11卷 34-45页

作者：黄麒 teh-Lung Ku Fred M.Phillips Institute of salt Lakes Academia Sinica Xining 810008 Department of Geological sciences University of Southern California Los Angeles CA. 90089-0740 U.S.A. Geoscience Department New Mexico Institute of Mining and Technology Socorro NM 87801 U.S.A

The Qaidam Basin is. a tectonically controlled depression at 2700 m altitude on the northern margin of the Tibet Plateau. A succession of Neogene clastic sediments indicates lake depocentre migration from NW to sE. Towards late Pliocene, evaporative conditions developed with formation of gypsum, halite, celestite, mirabilite and bloedite. Continued deformation through Pleistocene developed a series of NW- sE trending domes and troughs. This setting continued to exert a controlling influence on basin and brine evolution and the progressive development of sulfate to chloride brines as, dry conditions intensified in late Pleistocene, at the end of which, extensive flat floors were formed in Dalangtan, Qarhan and other ***, model, which was set up based on the synthetic analyses, divides the fluctuating palaeoclimate since 750ka,B. P. into 11 warm and humid stages and 10 dry and cold stages. The water of the lakes evaporated during the dry-cold periods and were freshened during the warm-humid

关键词： evolution of salt lakes organic carbon stratigraphy undulating model of paleoclimate

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Effect of Eu^(3+),Bi^(3+),and Li^(+) doping on luminescent property of GdNbO_(4)

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Journal of Rare Earths 2024年第1期42卷 66-75,I0003页

作者： s.W.Wi Y.s.Lee Department of Physics and Integrative Institute of Basic sciences Soongsil UniversitySeoul06978Republic of Korea

We investigated the emission properties of Eu^(3+)-doped GdNbO_(4)-based oxide phosphors,aiming at improving the Eu^(3+)emission by codoping of Bi^(3+)and Li^(+).Eu^(3+)singly doped,Eu^(3+)and Bi^(3+)doubly doped,and Eu^(3+),Bi^(3+),and Li^(+)triply doped GdNbO_(4)were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu^(3+)in the singly doped samples are significantly improved by the codoping of Bi^(3+),mainly due to the energy transfer from Bi^(3+)to Eu^(3+).The additional codoping of Li^(+)is found to increase the Eu^(3+)emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu^(3+)in GdNbO_(4)does not change significantly with the codoping of Bi^(3+)and Li^(+).Our results indicate that Li^(+)doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO_(4)phosphors.

关键词： Eu^(3+) GdNbO_(4) Codoping of Li^(+) Photoluminescence sensitizer Rare earths

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Nonrelativistic shannon information entropy for Kratzer potential

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Chinese Physics B 2016年第4期25卷 37-41页

作者： Najafizade s A Hassanabadi H Zarrinkamar s Physics Department University of Shahrood Department of Basic sciences Garmsar Branch Islamic Azad University

The shannon information entropy is investigated within the nonrelativistic framework. The Kratzer potential is con- sidered as the interaction and the problem is solved in a quasi-exact analytical manner to discuss the ground and first excited states. some interesting features of the information entropy densities as well as the probability densities are demonstrated. The Bialynicki-Birula-Mycielski inequality is also tested and found to hold for these cases.

关键词： schrOdinger equation Kratzer potential shannon entropy

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synthesis of Flower-Like Nanoparticles of Anatase Titania by Microwave solvo-Hydrothermal Method

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Acta Metallurgica sinica(English Letters) 2013年第6期26卷 742-746页

作者： s.Mahmoudi s.Boudjadar Ceramics Laboratory Department of PhysicsUniversity of Constantine

Anatase titania nanoparticles with an average size of about 14 nm were synthesized by microwave solvothermal method from TiCI4 and ethanol as a precursor and solvent respectively. The shapes of as prepared samples were modified by microwave hydrothermal treatment in strongly alkaline medium at 100℃ for 2 h, the agglomerate particles can be converted to the nanorods then to flower-like sphere. The structure, morphology and optical properties of as-prepared powders were investigated by X-ray diffraction, scanning electron microscopy and UV- vis absorption spectroscopy, the quality of the samples was examined by IR absorption spectroscopy and room temperature photoluminescence （PL）. The results showed that the synthesized Ti02 revealed the formation of the nanorods and the flower-like shape of titania after post treatment in 5 mol/L and 10 mol/L NaOH solution, respectively. IR absorption spectra showed that the as-prepared TiO2 nanocrystals were highly pure and strongly surface hydrated, The photoluminescence measurement showed that five main emission peaks appeared in UV, violet, blue and green regions.

关键词： Titanium dioxide Microwave hydrothermal Alkaline medium Flower-like Photoluminescence

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