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Friction 2015年第2期3卷 148-160页

作者： sissi de BEER G.DjuidjékENmOÉ martin h.mÜsER materials science and Technology of Polymers MESA+Institute for NanotechnologyUniversity of TwenteP.O.Box 2177500 AE Enschedethe Netherlands Jülich supercomputing Centre Institute for Advanced simulation FZ Jülich 52425 JülichGermany Department of Physics Laboratory of Mechanics Faculty of ScienceUniversity of YaoundéP.O.Box 812YaoundéCameroon

Computer simulations of friction between polymer brushes are usually simplified compared to real systems in terms of solvents and *** most simulations,the solvent is only implicit with infinite compressibility and zero *** addition,the model geometries are parallel walls rather than curved or rough as in *** this work,we study the effects of these approximations and more generally the relevance of solvation on dissipation in polymer-brush systems by comparing simulations based on different solvation *** find that the rate dependence of the energy loss during the collision of brush-bearing asperities can be different for explicit and implicit ***,the non-Newtonian rate dependences differ noticeably between normal and transverse motion,i.e.,between head-on and off-center asperity ***,when the two opposing brushes are made immiscible,the friction is dramatically reduced compared to an undersaturated miscible polymer-brush system,irrespective of the sliding direction.

关键词： polymer brushes biomimetic materials molecular dynamics simulation

Investigation of generalized Fick's and Fourier's laws in the second-grade fluid flow

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Applied mathematics and mechanics(English Edition) 2018年第11期39卷 1617-1630页

作者： T.hAYAT s.AhmAD m.I.khAN A.ALsAEDI Department of mathematics Quaid-i-Azam University Nonlinear Analysis and Applied mathematics (NAAm) Research Group Department of Mathematics Faculty of Science King Abdulaziz University

The second-grade fluid flow due to a rotating porous stretchable disk is modeled and analyzed. A porous medium is characterized by the Darcy relation. The heat and mass transport are characterized through Cattaneo-Christov double *** thermal and solutal stratifications at the surface are also accounted. The relevant nonlinear ordinary differential systems after using appropriate transformations are solved for the solutions with the homotopy analysis method(hAm). The effects of various involved variables on the temperature, velocity, concentration, skin friction, mass transfer rate, and heat transfer rate are discussed through graphs. From the obtained results,decreasing tendencies for the radial, axial, and tangential velocities are observed. Temperature is a decreasing function of the Reynolds number, thermal relaxation parameter,and Prandtl number. moreover, the mass diffusivity decreases with the schmidt number.

关键词： second-grade liquid thermal and solutal stratification Cattaneo-Christov double diffusion rotating stretchable disk

Enhancement of the sensitivity of Gas sensor Based on microstructure Optical Fiber

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Photonic sensors 2015年第4期5卷 312-320页

作者： monir mORshED md. Imran hAsAN s. m. Abdur RAZZAk Department of lnformation and Communication Technology Mawlana Bhashani Science and Technology University Tangail-1902 Bangladesh Department of Electronics & Telecommunication Engineering Rajshahi University of Engineering & Technology Rajshahi-6204 Bangladesh Department of Electrical & Electronic Engineering Rajshahi University of Engineering & Technology Rajshahi-6204 Bangladesh

This paper proposes the design and characterization of microstructure optical fiber for gas sensing applications. The aim is to detect toxic and colorless gases over a wide transmission band covering 0.80 gm to 2.00gm wavelength. Numerical investigation is carried out by using the finite element method （FEm）. The numerical study shows that sensitivity of the proposed sensor is moderately increased by introducing four non-circular holes around the defected core of photonic crystal fiber and the confinement loss is also reduced. Furthermore, we confirm that increasing the diameter of central air core and size of the non-circular holes can improve the relative sensitivity and the confinement loss is reduced by increasing the diameter of air holes in the cladding. The enhancement of the relative sensitivity is more than 27.58% （0.1323 to 0.1688） at the wavelength 2=1.33gm that is the absorption line of methane （Ch4） and hydrogen fluoride （hF） gases. The confinement loss of the fiber is 1.765x 10-8dB/m.

关键词： Confinement loss gas sensor hollow core photonic crystal fiber microstrucmre fiber relativesensitivity

Nanostructural Evolution of sugarcane Rind and Pith submitted to hydrothermal Pretreatments

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Journal of Renewable materials 2018年第2期6卷 152-159页

作者： marcelo m.Oliveira Antonio A.s.Curvelo Carlos Driemeier Brazilian Bioethanol science and Technology Laboratory(CTBE) Brazilian Center for Research in Energy and Materials(CNPEM)Caixa Postal 619213083-970CampinasSão PauloBrasil são Carlos school of Engineering(EEsC) University of São Paulo(USP)Caixa Postal 78013560-970São CarlosSão PauloBrasil são Carlos Institute of Chemistry(IQsC) University of São Paulo(USP)Caixa Postal 78013560-970São CarlosSão PauloBrasil

Lignocellulose conversion into cellulosic ethanol and coproducts starts with a pretreatment *** current industrial plants of cellulosic ethanol use thermochemical pretreatments under hydrothermal conditions,with or without addition of acid *** pretreatments modify biomass chemistry and morphology,particularly at the *** this work,we use X-ray diffraction,dynamic vapor sorption and calorimetric thermoporometry to investigate the biomass nanostructural changes promoted by hydrothermal *** compare and differentiate the rind and pith fractions of sugarcane stalks in order to contribute to the understanding of rind-pith contrasting ***,for both cane fractions our results point consistently to cellulose co-crystallization,lignin aggregation,and opening of nanoscale pores as the main nanostructural phenomena occurring during hydrothermal treatments.

关键词： Cellulose bagasse sugarcane cellulosic ethanol pretreatment

Fabrication and characterization of Ti6A14V/TiB2-TiC composites by powder metallurgy method

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Rare metals 2017年第10期36卷 806-811页

作者： m. Anandajothi s. Ramanathan V. Ananthi P. Narayanasamy Department of manufacturing Engineering Annamalai University Chidambaram Tamil Nadu 608 002 India Physics section Faculty of Engineering and Technology Annamalai University Chidambaram Tamil Nadu 608 002 India Department of mechanical Engineering Kamaraj College of Engineering and Technology Virudhunagar Tamil Nadu 626 001 India

Titanium matrix （Ti6Al4V） composites rein- forced with TiB2 and TiC were produced through powder metallurgy method. The effect of addition of both TiB2 and TiC with different contents （2.5 wt%, 5.0 wt% and 7.5 wt%） on the density, microstructure and hardness properties of titanium matrix was investigated. The size distributions of the matrix alloy and reinforcement particles were measured by particle size analyzer. microhardness of the sintered composites was evaluated using Vickers＇s hardness tester with a normal load of 3 N and a dwell time of 10 s. Ti6Al4V alloy and Ti6Al4V/TiB2-TiC composites were characterized through X-ray diffraction （XRD） and field emission scanning electron microscope （FEsEm） equipped with energy-dispersive spectrometer （EDs）. The addition of TiB2 and TiC particles enriches the properties of Ti6Al4V alloy. The sintered Ti6Al4V/TiB2-TiC composite features a dense and pore-free microstructure with varying TiB2 and TiC particle distribution in the metal matrix. The results of this study show that the development of new phases plays a significant role in the properties of these composite materials.

关键词： Ti6Al4V TiB2 TiC microstructure

spatio-Temporal Effect on soil Respiration in Fine-scale Patches in a Desert Ecosystem

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Pedosphere 2006年第1期16卷 1-9页

作者： s. PEN-mOURATOV m. RAkhImBAEV Y. sTEINBERGER Faculty of Life sciences Bar-Ilan University Ramat-Gan 52900 (Israel) Faculty of Life sciences Bar-Ilan University Ramat-Gan 52900 (Israel) Institute of Botany Tashkent (Uzbekistan)

soil organisms in terrestrial systems are unevenly distributed in time and space, and often aggregated. spatiotemporal patchiness in the soil environment is thought to be crucial for the maintenance of soil biodiversity, providing diverse microhabitats tightly interweaving with resource partitioning. Determination of a ＂scale unit＂ to help understand ecological processes has become one of the important and most debatable problems in recent years. A fieldwork was carried out in the northern Negev Desert highland, Israel to determine the influence of fine-scale landscape patch moisture heterogeneity on biogeochemical variables and microbial activity linkage in a desert ecosystem. The results showed that the spatio-temporal patchiness of soil moisture to which we attribute influential properties, was found to become more heterogenic with the decrease in soil moisture availability （from 8.2 to 0.4 g kg^-1） toward the hot, dry seasons, with coefficient of variation （CV） change amounting to 66.9%. spatio-temporal distribution of organic matter （Om） and total soluble nitrogen （TsN） was found to be relatively uniformly distributed throughout the wet seasons （winter and spring）, with increase of relatively high heterogeneity toward the dry seasons （from 0.25% to 2.17% for Om, and from 0 to 10.2 mg kg^-1 for TsN） with CV of 47.4% and 99.7% for Om and TsN, respectively. Different spatio-temporal landscape patterns were obtained for Ca （CV = 44.6%）, k （CV = 34.4%）, and Na （CV = 92%） ions throughout the study period. CO2 evolution （CV = 48.6%） was found to be of lower heterogeneity （varying between 2 and 39 g CO2-C g^-1 dry soil h^-1） in the moist seasons, e.g., winter and spring, with lower values of respiration coupled with high heterogeneity of Na^＋ and low levels of TsN and organic matter content, and with more homogeneity in the dry seasons （varying between 1 and 50 g CO2-C g^-1 dry soil h^-1）. Our results elucidate the heterogeneity and complexity of desert system habitats

关键词： desert microbial respiration patchiness small-scale habitat soil

Novel micro-ring structured ZnO photoelectrode for dye-sensitized solar cell

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Nano-micro Letters 2010年第1期2卷 53-55页

作者： m.F.hossain Z.h.Zhang T.Takahashi Graduate school of science and Engineering for Education University of Toyama Graduate school of science and Engineering for Research University of Toyama

The micro-ring like structured zinc oxide(ZnO) film was deposited on snO_2: F coated glass substrate by sol-gel dip-coating technique with 1.0 g polyethylene glycol(PEG) content. The surface morphology of micro-ring structured ZnO film has been confirmed by the scanning electron microscope. This ZnO film is used to fabricate the solar cell with the help of ruthenium based dye and carbon counter electrode. The photoelectric and incident photon-to-current conversion efficiency was 1.17% and 48.4%, respectively. The DsC results have been compared with ZnO films prepared without PEG contents.

关键词： Zinc oxide Dye-sensitized solar cell Polyethylene glycol

^(68)Gallium-labelled PsmA-PET/CT as a diagnostic and clinical decision-making tool in Asian prostate cancer patients following prostatectomy

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Cancer Biology & medicine 2019年第1期16卷 157-165页

作者： Janice s.h.Tan Charles X.Y.Goh Yen sin koh Youquan Li Jeffrey k.L.Tuan Eu Tiong Chua Terence W.k.Tan michael L.C.Wang Lui shiong Lee kae Jack Tay Ravindran kanesvaran Chee keong Toh Aaron k.T.Tong Winnie W.C.Lam melvin L.k.Chua Division of Radiation Oncology National Cancer Centre Singapore Department of Nuclear medicine and molecular Imaging Singapore General Hospital Radiological sciences Academic Clinical Programme Duke-NUS Medical School Oncology Academic Clinical Programme Duke-NUS Medical School Department of Urology Singapore General Hospital Department of surgery Sengkang General Hospital Division of medical Oncology National Cancer Centre Singapore Division of medical sciences National Cancer Centre Singapore

Objective: Prostate cancers(PCa) in Asian individuals are molecularly distinct from those found in their Caucasian *** is no risk stratification tool for Asian men with rapid biochemical recurrence(BCR) following radical prostatectomy(Rad P). This study aims to assess the detection rate of ^(68)Ga-prostate-specific membrane antigen-positron emission tomography/computed tomography(PsmA-PET/CT) for diagnosis of clinical recurrence and as a treatment decision making tool in Asian patients with BCR post-Rad ***: ^(68)Ga PsmA-PET and CT body with/without bone scan [conventional workup(CWU)] were performed in 55 Asian patients with BCR within 36 months post-Rad P. Two blinded reviewers assessed the images. Detection rates of ^(68)Ga PsmAPET/CT were evaluated, and impact on management was reviewed by comparison with ***: median time to BCR post-Rad P was 8.1 months. Detection rate for ^(68)Ga PsmA-PET/CT was 80%(44/55). A positive scan was significantly associated with increasing prostate-specific antigen(PsA) level [odds ratio(OR) = 1.13(95% CI 1.05–1.30), P =0.017], but not with higher Gleason grade or shorter PsA doubling time. Compared to CWU, ^(68)Ga PsmA-PET/CT detected an additional 106 lesions in 33/44 patients with a positive scan, resulting in a change in management in 25/44(56.8%) patients: 10 to hormonal therapy(hT) and whole pelvis radiotherapy(RT) in addition to bed RT, and 15 to palliative hT ***: In the present report, we demonstrated the diagnostic and treatment decision utility of ^(68)Ga PsmA-PET/CT in Asian men with rapid BCR. Detection of small volume nodal and systemic recurrences at low PsA levels(mL) highlights the role of the tool in assigning patients to treatment intensification with hT-RT or palliative hT in polymetastatic disease.

关键词： ^68Ga PsmA PET/CT prostate cancer Asian diagnostic recurrence prostatectomy salvage radiotherapy

Production of geopolymer composites enhanced by nano‐kaolin material

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Journal of Advanced Ceramics 2015年第4期4卷 245-252页

作者： mahmoud m.hAssAAN hisham m.khATER medhat s.EL-mAhLLAWY Abdeen m.EL NAGAR Al Azhar University Nasr CityCairoEgypt housing and Building National Research Centre(hBRC) 87 El-Tahrir St.DokkiGizaP.O.Box 1770CairoEgypt

Nowadays kaolin raw material is usually used to produce nano-kaolin for geopolymer enhancement by using firing *** the present study,kaolin used was taken from the Naqus Formation(Cambro-Ordovician age),west of Gabal El Gunna,sinai,***-kaolin material is an ultrafine material and was prepared from the taken kaolin by the firing process at 800 for 2℃h with a heating rate of 5/*** mixes were prepared and their laboratory specimens were made℃and cured up to 90 *** cooled slag was used as starting material,and sodium hydroxide and sodium silicate were used in the study as activators for the used *** formed geopolymer mixes with different ratios(1%,1.5%,3%,5%,and 7%)of nano-kaolin as a partial replacement for the raw kaolin were *** Ace super plasticizer was added in the ratio of 4%from the dry weight to ensure good dispersing of the used nano *** showed that increasing the percentage of nano-kaolin up to 3%results in an enhancement in the mechanical properties as compared with the control mix up to 90 days of curing,while higher ratios are not preferable where they lead to agglomeration of the added nano materials and matrix dilution.

关键词： geopolymer nano-kaolin sodium silicate slag

Positron-Acoustic shock Waves in a Degenerate multi-Component Plasma

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Chinese Physics Letters 2015年第8期32卷 111-115页

作者： shah m. G. hossen m. R. sultana s. mamun A. A. Department of Physics Jahangirnagar University Savar Dhaka-1342 Bangladesh Department of Natural sciences Daffodil International University Dhanmondi Dhaka-1207 Bangladesh

A theoretical investigation on the propagation of positron-acoustic shock waves （PAsWs） in an unmagnetized, collisionless, dense plasma （containing non-relativistic inertial cold positrons, non-relativistic or ultra-relativistic degenerate electron and hot positron fluids and nondegenerate positively charged immobile ions） is carried out by employing the reductive perturbation method. The Burgers equation and its stationary shock wave solution are derived and numerically analyzed. It is observed that the relativistic effect （i.e., the presence of non/ultra- relativistic electrons and positrons） and the plasma particle number densities play vital roles in the propagation of PAsWs. The implications of our results in space and interstellar compact objects including non-rotating white dwarfs, neutron stars, etc. are briefly discussed.

关键词： Positron-Acoustic shock Waves in a Degenerate multi-Component Plasma