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Synthesis of Anatase Titania Nanostructures at Room Temperature by PECVD Technique

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Journal of materials Science & Technology 2011年第8期27卷 696-700页

titania nanostructures have been synthesized at room temperature by plasma enhanced chemical vapor deposition （PECVD） process on silicon （100） substrates using titanium tetraisopropoxide [Ti（OC3H7）4, TTIP] vapor, argon and oxygen mixtures under various deposition pressures. The deposited titania has been characterized for its structural, morphological and chemical composition by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray （EDX） spectroscopy and Fourier transform infrared （FTIR） spectroscopy recordings. With the variation of deposition pressure, titania assumes various nanostructures viz. nanocrystals, nanoparticles, noanorods and comb-like structure. EDX and FTIR measurements show that the deposited titania is of high chemical purity. The possible growth mechanisms for the observed titania nanostructures have been discussed.

关键词： Nanostructures Plasma enhanced chemical vapor deposition Anatase titania

Effect of Oxygen Admittance Temperature on the Growth of ZnO microcrystals by Thermal Evaporation Technique

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Journal of materials Science & Technology 2012年第4期28卷 317-320页

作者： k.m.k. srivatsa Deepak Chhikara m. Senthil kumar Physics of Energy Harvesting Division National Physical Laboratory Council of Scientific & Industrial Research (CSIR) New Delhi 110012 India

Hexagonally well-faceted microcrystals of ZnO have been grown by thermal evaporation of Zn powder in oxygen ambient at 700℃ under atmospheric pressure. It has been observed that the properties （size and quality） of ZnO microcrystals have a strong dependence on the reactor temperature at which the oxygen gas is admitted into the growth zone. The microcrystals grown with oxygen admittance at 450℃ have a length of 1 μm and a diameter of 0.75 μm while that grown with oxygen admittance at 600 ℃ have a length of 1.5-2 μm and a diameter of 1 μm. Room temperature photoluminescence spectra show a ultraviolet （UV） emission peak at 385 nm with a green band emission at around 500 nm. The UV-to-green band emission ratio for the microcrystals grown with oxygen admittance at 450℃ is observed to be 1.25 and the ratio decreases to 0.45 for the sample grown with oxygen admittance at 600℃.

关键词： ZnO microcrystals Thermal evaporation Scanning electron microscopy Transmission electron microscopy Room temperature photoluminescence

Regression analysis of squeezing-induced hybrid nanofluid flow in Darcy-Forchheimer porous medium

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Applied mathematics and mechanics(English Edition) 2025年第1期46卷 193-208页

作者： k.mUHAmmAD m.SARFRAZ Department of Humanities and Sciences School of Electrical Engineering and Computer Science National University of Sciences and Technology Department of mathematics Quaid-i-Azam University

This article presents a mathematical model addressing a scenario involving a hybrid nanofluid flow between two infinite parallel plates. One plate remains stationary, while the other moves downward at a squeezing velocity. The space between these plates contains a Darcy-Forchheimer porous medium. A mixture of water-based fluid with gold(Au) and silicon dioxide(Si O2) nanoparticles is formulated. In contrast to the conventional Fourier's heat flux equation, this study employs the Cattaneo-Christov heat flux equation. A uniform magnetic field is applied perpendicular to the flow direction, invoking magnetohydrodynamic(mHD) effects. Further, the model accounts for Joule heating, which is the heat generated when an electric current passes through the fluid. The problem is solved via NDSolve in mATHEmATICA. Numerical and statistical analyses are conducted to provide insights into the behavior of the nanomaterials between the parallel plates with respect to the flow, energy transport, and skin *** findings of this study have potential applications in enhancing cooling systems and optimizing thermal management strategies. It is observed that the squeezing motion generates additional pressure gradients within the fluid, which enhances the flow rate but reduces the frictional drag. Consequently, the fluid is pushed more vigorously between the plates, increasing the flow velocity. As the fluid experiences higher flow rates due to the increased squeezing effect, it spends less time in the region between the plates. The thermal relaxation, however, abruptly changes the temperature, leading to a decrease in the temperature fluctuations.

关键词： convective boundary condition Darcy-Forchheimer medium hybrid nanofluid Joule heating magnetohydrodynamic (mHD) numerical solution O175.2 O361 regression analysis squeezing flow

Honeycomb-spiderweb-inspired self-similar hybrid cellular structures for impact applications

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Defence Technology(防务技术) 2025年第1期43卷 182-200页

作者： k.Tewari m.k.Pandit m.m.mahapatra P.R.Budarapu School of mechanical Sciences Indian Institute of Technology BhubaneswarBhubaneswar752050India

Inspired by nature's self-similar designs,novel honeycomb-spiderweb based self-similar hybrid cellular structures are proposed here for efficient energy absorption in impact *** energy absorption is enhanced by optimizing the geometry and topology for a given *** proposed hybrid cellular structure is arrived after a thorough analysis of topologically enhanced self-similar *** optimized cell designs are rigorously tested considering dynamic loads involving crush and high-velocity bullet ***,the influence of thickness,radial connectivity,and order of patterning at the unit cell level are also *** maximum crushing efficiency attained is found to be more than 95%,which is significantly higher than most existing traditional *** on,the first and second-order hierarchical self-similar unit cell designs developed during crush analysis are used to prepare the cores for sandwich *** tests are performed on the developed sandwich structures using the standard 9-mm *** influence of multistaging on impact resistance is also investigated by maintaining a constant total thickness and mass of the sandwich ***,in order to avoid layer-wise weak zones and hence,attain a uniform out-of-plane impact strength,off-setting the designs in each stage is *** sandwich structures with first and second-order self-similar hybrid cores are observed to withstand impact velocities as high as 170 m/s and 270 m/s,respectively.

关键词： Sandwich structures Honeycomb-spider web inspired Self-similar hierarchy Crush analysis High-velocity impact Strong and weak zones multistaging

Photoluminescence upgradation of La_(2)mgTiO_(6):2%Dy^(3+) perovskite with monovalent(Li^(+)),divalent(Ba^(2+),Sr^(2+)) and trivalent(Bi^(3+),Sm^(3+))cation sensitization

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Journal of Rare Earths 2025年第1期43卷 47-56,I0002页

作者： V.P.Veena k.Arun C.k.Shilpa S.V.Jasira k.m.Nissamudeen School of Pure and Applied Physics Kannur UniversityPayyanur CampusEdatKannurKrala67 India Department of Nanoscience and Nanotechnology Kannur UniversityPayyanur CampusEdatkannurKerala670327India

Nano phosphors of 2%Dy^(3+)(wt%)doped La_(2)mgTiO_(6) and monovalent/divalent/trivalent co-doped La_(1.98)Dy_(0.02)mgTiO_(6):x%A^(y+)(A^(y+):Li+,Ba^(2+),Sr^(2+),Bi^(3+),and Sm^(3+);0≤x≤2 wt%)were synthesized by combustion *** the XRD data,it is deduced that an increase in the valency of co-dopant increases the crystallinity of the double perovskite orthorhombic nanocrystal *** an increase in co-dopant size,an elevation in optical bandgap is visible with the highest bandgap of 3.835 eV for Bi^(3+).The photo-absorption is monotonically broadened for Sr^(2+),Sm^(3+),and Li+around 200-450 ***351 nm,Dy^(3+)triggered lattice shows major characteristic emission peaks at 480 nm(^(4)F_(9/2)→^(6)H_(15/2)),574 nm(^(4)F_(9/2)→^(6)H_(13/2)),and 670 nm(^(4)F_(9/2)→^(6)H_(11/2)).leading to near white light emission with CIE coordinates(0.341,0.376).Upon co-doping,the PL intensity is significantly increased with maximum emission for trivalent Sm^(3+),followed by divalent Sr^(2+)and monovalent Li+*** increasing excitation wavelength,Sr^(2+)shows a dominated output and it is found that divalent Sr^(2+)is a potential codopant that could enhance luminescence intensity up to 6 times with a Sr^(2+)→Dy^(3+)energy transfer efficiency of 86%.It is specified that the CIE coordinates of Li+co-doped samples show ideal white emission with color coordinates(0.333,0.336).The concluding outcomes signify the noblest rare earth Sm^(3+)co-doping and thus Sm^(3+)→Dy^(3+)energy transfer mechanism is discussed in detail.

关键词： Photoluminescence Perovskite WLED Co-doping Rareearths

The effect of adsorbent textural and functional properties on model naphthenic acid adsorption

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Journal of Environmental Sciences 2025年第2期148卷 27-37页

作者： Tyler m.Roy Elmira Nazari Oliver k.L.Strong Paul R.Pede Andrew J.Vreugdenhil material Science Department of ChemistryTrent University1600 West BankPeterboroughOntario K9L 0G2Canada Carbonix 690 Mountain RdSuite 200Fort William First NationOntario P7J 1G8Canada

Naphthenic acids,NAs,are a major contaminant of concern and a focus of much research around remediation of oil sand process affected waters,*** activated carbon adsorbents are an attractive option given their low cost of fabrication and implementation.A deeper evaluation of the effect NA structural differences have on uptake affinity is *** we provide an in-depth exploration of NA adsorption including many more model NA species than have been assessed previously with evaluation of adsorption kinetics and isotherms at the relevant alkaline pH of OSPW using several different carbon adsorbents with pH buffering to simulate the behaviour of real *** for the NA varied considerably regardless of the activated carbon used,ranging from 350 mg/g to near zero highlighting recalcitrant *** equilibrium data was explored to identify structural features of these species and key physiochemical properties that influence *** found that certainNAwill be resistant to adsorptionwhen hydrophobic adsorbents are *** isotherm modelling helped explore interactions occurring at the interface between NA and adsorbent *** identified the importance of NA hydrophobicity for activated carbon *** is also presented that indicates favorable hydrogen bonding between certain NA and surface site hydroxyl groups,demonstrating the importance of adsorbent surface functionality for NA *** research highlights the challenges associated with removing NAs from OSPW through adsorption and also identifies howadsorbent surface chemistry modification can be used to increase the removal efficiency of recalcitrant NA species.

关键词： Adsorption Activated carbon model naphthenic acids Isotherm modelling

Efficacy of antimicrobials in preventing resistance in solid organ transplant recipients:A systematic review of clinical trials

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World Journal of Transplantation 2025年第1期15卷 156-164页

作者： Carlos m Ardila Pradeep k Yadalam Jaime Ramírez-Arbelaez Department of Basic Sciences Faculty of Dentistry Biomedical Stomatology Research GroupUniversidad de Antioquia U de AMedellín 0057Colombia Department of Postdoctoral Program CIFE University CenterCuernavaca 62330MorelosMexico Department of Periodontics Saveetha Dental CollegeSaveetha Institute of Medical and HealthSIMATSSaveetha UniversityChennai 600077Tamil NaduIndia Department of Transplantation Hospital San Vicente FundaciónRionegro 054047Colombia

BACkGROUND In the absence of effective antimicrobials,transplant surgery is not viable,and antirejection immunosuppressants cannot be administered,as resistant infections compromise the life-saving goal of organ *** To evaluate the efficacy of antimicrobials in preventing resistance in solid organ transplant *** A systematic review was conducted using a search methodology consistent with the preferred reporting items for systematic reviews and *** review included randomized clinical trials that evaluated the efficacy of antimicrobial agents(prophylactic or therapeutic)aimed at preventing antimicrobial *** search strategy involved analyzing multiple databases,including Pubmed/mEDLINE,Web of Science,Embase,Scopus,and SciELO,as well as examining gray literature sources on Google Scholar.A comprehensive electronic database search was conducted from the databases’inception until may 2024,with no language *** After the final phase of the eligibility assessment,this systematic review ultimate-ly included 7 articles.A total of 2318 patients were *** most studied microorganisms were cytomegalovirus,although vancomycinresistant enterococci,Clostridioides difficile,and multidrug-resistant Enterobacterales were also *** antimicrobials used in the interventions were mainly maribavir,valganciclovir,gancic-lovir,and *** concern,all clinical trials showed significant proportions of resistant microorga-nisms after the interventions,with no statistically significant differences between the groups(mean resistance 13.47%vs 14.39%),except for two studies that demonstrated greater efficacy of maribavir and valganciclovir(mean resistance 22.2%vs 41.1%in the control group;Pmicrobial-resistant microor

关键词： Antimicrobial resistance Antimicrobials Antivirals Solid organ transplant recipients Infections microorganisms Cytomegalovirus

Hybrid and enhanced electrokinetic system for soil remediation from heavy metals and organic matter

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Journal of Environmental Sciences 2025年第1期147卷 424-450页

作者： Faris m.Hamdi Namuun Ganbat Ali Altaee Akshaya k.Samal Ibrar Ibrar John L.Zhou Adel O.Sharif Centre for Green Technology School of Civil and Environmental EngineeringThe University of Technology Sydney15 BroadwayNSW 2007Australia Department of Civil Engineering Jazan UniversityJazan 82822Saudi Arabia Centre for Nano and material Sciences Jain UniversityRamanagaraBangaloreKarnataka 562112India School of mechanical Sciences Faculty of Engineering and Physical SciencesUniversity of SurreyAustralia

The electrokinetic(Ek)process has been proposed for soil decontamination from heavy metals and organic *** advantages of the Ek process include the low operating energy,suitability for fine-grained soil decontamination,and no need for *** the last three decades,enhanced and hybrid Ek systems were developed and tested for improving the efficiency of contaminants removal from *** enhanced-Ek processes exhibited excellent efficiency in removing contaminants by controlling the soil pH or the chemical reaction of *** hybrid systems were tested to overcome environmental hurdles or technical drawbacks of decontamination *** of the Ek process with phytoremediation,bioremediation,or reactive filtermedia(RFm)improved the remediation process performance by capturing contaminants or facilitating biological agents’movement in the ***,Ek process coupling with solar energy was proposed to treat off-grid contaminated soils or reduce the Ek energy *** study reviews recent advancements in the enhancement and hybrid Ek systems for soil remediation and the type of contaminants targeted by the *** study also covered the impact of operating parameters,imperfect pollution separation,and differences in the physicochemical characteristics and microstructure of soil/sediment on the Ek ***,a comparison between various remediation processes was presented to highlight the pros and cons of these technologies.

关键词： Electrokinetic Soil remediation Reactive filter media Enhanced electrokinetic Contaminants

Effects of rare-earth Pr3+-Dy3+ doping on structural,magnetic,optical and dielectric properties of Zn2Y hexaferrite

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Journal of Rare Earths 2025年第2期43卷 329-336页

作者： Ibrahim mohammed mohamed E.El Sayed Ali Shawabkeh mohammad N.murshed Ibtehaj F.Alshdoukhi Zeinhom m.El-Bahy J.mohammed A.k.Srivastava Department of Physics Lovely Professional University Department of Science Technology Waziri Umaru Federal Polytechnic Birnin Kebbi Physics Department Faculty of Science and ArtsKing Khalid University College of Engineering and Technology American University of the Middle East Department of Basic Sciences College of Science and Health ProfessionsKing Saud Bin Abdulaziz University for Health ScienceKing Abdullah International Medical Research Center Department of Chemistry Faculty of ScienceAl-Azhar University Department of Physics Faculty of ScienceFederal University Dutse

This study was conducted to investigate the properties of Pr3+-Dy3+doped Zn2Y-type hexaferrite for potential technological applications.X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FTIR） and field-emission scanning electron microscopy（FESEm） were used to analyze structural *** crystallite size in the synthesized samples varies between 57.54 and 68.57 *** vibrational bands at 400 and 600 cm-1,common to all hexaferrites,were confirmed through *** FESEm analysis reveals an agglomeration of magnetic grains and a decrease in the average grain size from 1.24 to1.06 μ*** m-H loops show that,with x values of 0.0,0.1,and 0.2,the saturation magnetization is determined to be 34.76,34.23,and 32.52 emu/g,*** corresponding coercivity values are21.24,30.39,and 33.99 ***-visible spectroscopy using Tauc theory reveals an increase in the optical band gap from 2.32 to 2.50 eV,indicating a tunable energy band structure by incorporating Pr3+-Dy3+*** dielectric constant increases,whereas AC conductivity decreases with increased Pr3+-Dy3+*** obtained results suggest the potential suitability of these materials for various technological applications.

关键词： Dielectric constant magnetic hysteresis Optical band gap Pr3+-Dy3+ Rare earths Zn2Y-type hexaferrite