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Comparative study of 2mol% Li- and Mn-substituted lead-free potassium sodium niobate ceramics

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International journal of Minerals,Metallurgy and Materials 2014年第12期21卷 1241-1246页

作者： Asha Dahiya O.P.Thakur j.K.juneja Sangeeta singh Dipti School of Applied Sciences Netaji Subhas Institute of Technology Dwarka University of Delhi Department of Physics Hindu College Department of Physics Geeta Vidya Mandir Girls College School of Physics & Material Sciences Thapar University

The effect of Li and Mn substitution on the dielectric, ferroelectric and piezoelectric properties of lead free K0.5Na0.5NbO3 （KNN） was investigated. Samples were prepared using a conventional solid state reaction method. The sintefing temperature for all the samples was 1050℃. The optimum doping concentration for the enhancement of different properties without the introduction of any other co-dopants such as Ti, Sb, and La was investigated. X-ray diffraction analysis confirmed that all the samples crystallize in a single phase perovskite structure. The dielectric properties were investigated as a function of temperature and applied electric field frequency. Compared with Li-substituted KNN （KLNN）, Mn-substituted KNN （KMNN） exhibited a higher dielectric constant εmax （i.e., 4840） at its critical transition temperature Tc （i.e., 421℃） along with a lower value of tangent loss at 10 kHz and greater values of saturation polarisation Ps （i.e., 20.14 μC/cm^2） and remnant polarisation Pr （i.e., 15.48 μC/cm^2）. The piezoelectric constant （d33） of KMNN was 178 pC/N, which is comparable to that of lead-based hard ceramics. The results presented herein suggest that B-site or Mn substitution at the optimum concentration results in good enhancement of different properties required for materials used in memory devices and other applications.

关键词： ceramics dielectric properties ferroelectricity piezoelectricity substitution comparative study

Understanding human-leopard conflict in the ‘Mid-hill’ region of western Nepal

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journal of Mountain Science 2023年第12期20卷 3464-3475页

作者： LAMICHHANE Saroj THAPA Arjun THAPA Mahendra singh PANTHI Saroj GIORDANO Anthony j School of Forestry and Natural Resources Management Institute of ForestryKirtipur 44613Nepal Institute of Fundamental Research and Studies(InFeRS) Baniyatar 44608Nepal Institute of Zoology Chinese Academy of SciencesBeijing 100101China Institute of Forestry Office of DeanKirtipur 44613Nepal Ministry of Industry TourismForest and EnvironmentKaski 33700Nepal SPECIES-The Society for the Preservation of Endangered Carnivores and their International Ecology Study VenturaCA 93006USA

Livestock rearing and agriculture are the main sources of community-based livelihoods in western *** the rural mid-hills region of Gandaki Province,leopards are the top predator and frequently depredate livestock and attack *** patterns of human-leopard conflicts(HLC) in Nepal are poorly known at the provincial and national scales,which are essential to formulating effective conflict mitigation strategies and implementing them in the *** study aims to analyze the spatiotemporal pattern of HLC by applying Maxent modeling to covariates relating to known and registered conflict cases(n=842) collected from Nepalese government *** found that cases of HLC have been increasing significantly over the past five *** also concluded that mid-elevation,south-facing slopes were more susceptible to HLC,but that mean annual temperature was by far the most important predictor of HLC;overall livestock density and proximity to roads were also important,but secondarily *** we found the increase in human fatalities to 2.16/year was significant(pjuries were down slightly,though not significantly(5.16/year;p>0.05).However,we also found an increasing trend in livestock depredation rates for this same five-year period(p<0.05),which averaged 159.6 head/year among incidents *** also found that winter was the main season when depredations occurred,and that goats were the most depredated of all livestock.A total US $86,892.25($17,378.45/year) of economic losses were incurred by communities during this time,with 78.57% of the total value reimbursed as compensatory relief through the government’s relief *** recommend that the use of predator-proof livestock corrals,greater awareness in local communities about wildlife behavior,better animal husbandry and security practices,and a more efficient compensation program,can improve coexistence between leopard populations and human communities in western Nepal.

关键词： Coexistence Compensation Economic loss Human-wildlife conflict Livestock depredation Maximum entropy Problem animals Sustainable livelihood

SiO2-coated pure anatase TiO2 catalysts for enhanced photo-oxidation of naphthalene and anthracene

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Particuology 2017年第5期15卷 156-161页

作者： Inderpreet singh Grover Roop Chand Prajapat Satnam singh Bonamali Pal Department of Chemistry Public College Samana 147101 Punjab India School of Chemistry and Biochemistry Thapar University Putiala 147004 Punjab India

Our current efforts reveal the preparation of SiO2@TiO2 nanocomposites having different thicknesses of silica shell and the relationship to photocatalytic activity （PCA） for the photo-oxidation of naph-thalene and anthracene. The presence of SiO2 coating over TiO2 surface was demonstrated by FT-IR analysis, with peaks corresponding to Si-O-Si （1081 cm 1） and Si-O-Ti （950 cm-1） bonds observed. High-resolution transmission electron microscopy analysis confirmed the presence of SiO2 in the as- prepared nanocomposites and the amount of Si, Ti, and O was determined by energy dispersive X-ray spectroscopy analysis. Increasing the Si02 shell thickness increases the surface area of the nanocompos- ites （69-235 m2/g）, which enhances naphthalene/anthracene adsorption. However, the observed PCA trend presents an inverse correlation to the adsorption studies, where the as-prepared samples possess- ing the highest surface areas exhibited the least PCA, while catalysts having lower surface areas （among silica coated samples） displayed the highest PCA in the degradation of naphthalene and anthracene to CO2. Despite complete degradation of naphthalene and anthracene, incomplete mineralization occurred, ascribed to the formation of various intermediates, identified by GC-MS analysis.

关键词： Silica coating Naphthalene Anthracene Photo-oxidation TiO2 nanoparticles

印度城市中产阶级正常血压、正常高值血压和高血压人群的患病率、知晓率、治疗率及控制率调查

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中华高血压杂志 2013年第6期21卷 598-598页

作者： Gupta R Deedwania PC Achari V Bhansali A Gupta BK Gupta A Mahanta TG Asirvatham Aj Gupta S Maheshwari A Saboo B jali MV singh j Guptha S Sharma KK 罗冬梅叶鹏

该研究为一多中心研究，研究印度城市中产阶级正常血压、正常高值血压和高血压人群的发病率与影响因素以及知晓率、治疗率和控制率。方法：从11个城市选取中产阶级人群6106名（男3371名，女2735名），评估他们的社会人口学和生物学因素... 详细信息

该研究为一多中心研究，研究印度城市中产阶级正常血压、正常高值血压和高血压人群的发病率与影响因素以及知晓率、治疗率和控制率。方法：从11个城市选取中产阶级人群6106名（男3371名，女2735名），评估他们的社会人口学和生物学因素，应答率62％。

关键词：正常高值血压高血压人群正常血压知晓率控制率治疗率城市印度

Heat transfer and fluid flow analysis of an artificially roughened solar air heater： a CFD based investigation

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Frontiers in Energy 2014年第2期8卷 201-211页

作者： Anil singh YADAV j. L. BHAGORIA Mechanical Engineering Department Technocrats Institute of Technology-Excellence Bhopal MP 462021 Mechanical Engineering Department Maulana Azad National Institute of Technology Bhopal MP 462051 India

In this paper, the effect of rib （circular sectioned） spacing on average Nusselt number and friction factor in an artificially roughened solar air heater （duct aspect ratio, AR= 5：1） is studied by adopting the computational fluid dynamics （CFD） approach. Numerical solutions are obtained using commercial software ANSYS FLUENT v12.1. The computations based on the finite volume method with the semi-implicit method for pressure-linked equations （SIMPLE） algorithm have been conducted. Circular sectioned transverse ribs are applied at the underside of the top of the duct, i.e., on the absorber plate. The rib-height-to-hydraulic diameter ratio （e/D） is 0.042. The rib-pitch-to-fib-height （P/e） ratios studied are 7.14, 10.71, 14.29 and 17.86. For each rib spacing simulations are executed at six different relevant Reynolds numbers from 3800 to 18000. The thermo-hydraulic performance parameter for P/e = 10.71 is found to be the best for the investigated range of parameters at a Reynolds number of 15000.

关键词： heat transfer pressure drop thermo-hydraulic performance parameter

Enhanced visible-light photocatalytic activity of samarium-doped zinc oxide nanostructures

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journal of Rare Earths 2020年第1期38卷 29-38页

作者： Sukriti Prakash Chand Vishal singh Department of Physics National Institute of TechnologyKurukshetra 136119India Centre for Materials Science&Engineering National Institute of TechnologyHamirpur 177005India

In the present work,we have synthesized samarium doped zinc oxide nanostructures(Zn1-xSmxO;x=0.00,0.02,0.04 and 0.06) via chemical precipitation method and studied their structural,morphological,optical and photocatalytic properties.X-ray diffraction(XRD) patterns,PL and Raman spectra results indicate that the undoped and Sm-doped ZnO nanostructures are crystallized in a hexagonal wurtzite *** images show that the morphology of the sample changes from cubical to hexagonal nanostructures with increase in Sm3+doping *** EDX spectra confirm the incorporation of Sm3+ion in *** influence of Sm3+doping on the structure,morphology,absorption,emission and photocatalytic activity of ZnO nanostructures were investigated *** addition of Sm3+ion leads to a red shift in the optical energy band gap from 3.19 to 2.67 eV and hence,increases the visible light absorption *** presence of E2(H) and E1(LO) modes in microRaman spectra confirms the crystallinity and defects in the *** detailed photocatalytic experiments reveal that Sm-doped ZnO nanostructures show the maximum photodegradation efficiency for Methylene blue(MB) dye for x=0.04,i,e.,94.94%,under visible light *** photocatalytic efficiency improves by 6.98 times when ZnO is doped with rare earth metal ion(Sm3+) and is a potential candidate for practical *** investigation demonstrates that as-synthesized nano-sized photocatalysts act as an efficient photocatalyst for the degradation of MB dye.

关键词： Photocatalysis Sm-doped ZnO FESEM Micro-Raman UV-Visible spectroscopy Rare earths

Multispectral harvesting rare-earth oxysulphide based highly efficient transparent luminescent solar concentrator

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journal of Rare Earths 2022年第1期40卷 41-48页

作者： Vanjula Kataria Dalip singh Mehta Green Photonics Laboratory Department of PhysicsIndian Institute of Technology(IIT)DelhiHauz KhasDelhi110016India

Transparent luminescent solar concentrator(LSC)is extensively regarded as the most promising sunlight tapping device for its application in buildings integrated with photovoltaics(BIPV)or as solar window *** LSCs doped with organic dyes suffered from high reabsorption losses with no transparency;whereas,recently reported heavy metal-doped quantum dots avoided such losses but possessed the risk of high toxicity and low ambient ***,luminophores with massive spectral shifts and co rdial relationships with the enviro nment are very much *** this paper,we report the fabrication of PMMA based transparent LSC embedded with nanocrystals of environmental friendiness and multispectral harvesting gadolinium oxysulphide(Gd_(2)O_(2) S:Er,Yb)*** Gd_(2)O_(2) S:Er,Yb nanofluorophore absorbs various excitation wavelengths ranging from UV to NIR and emits in the visible region offering huge Stoke’s and anti-Stoke’s shift *** non-existent reabsorption losses and overlapping maxima of Gd_(2)O_(2) S:Er,Yb nanofluorophore generated photon flux with solar cells’responsivity enhance the efficiency characteristics of the LSC *** analysis of LSC as a function of varying nanofluorophore dispersion ratio and changing edge width optimizes the fabrication process and exhibits high power conversion efficiency of-6,93%and optical efficiency of-8.57%.The LSC slab demonstrates high photostability under irradiation for prolonged hours without any dip in the emission *** Gd_(2)O_(2) S:Er,Yb nanofluorophore diffused LSC waveguide offering spectral tunability,cost-reduction,efficiency enhancement,and high concentration factor whilst being sustainable for long term use makes it a fascinating transparent solar window.

关键词： Luminescent solar concentrator Gadolinium oxysulphide Stoke's shift Anti-Stoke's shift Efficiency enhancement Photostability

Omental flaps reduces complications after pancreaticoduodenectomy

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Hepatobiliary & Pancreatic Diseases International 2015年第3期14卷 313-319页

作者： Omar j Shah Sadaf A Bangri Manmohan singh Reyaz A Lattoo Mohammad Y Bhat Department of Surgical Gastroenterology Sher-i-Kashmir Institute of Medical Sciences

BACKGROUND： Major complications after pancreaticoduo- denectomy are usually caused by a leaking pancreaticojejunal anastomosis. Omental flaps around various anastomoses were used to prevent the formation of fistula.

关键词： pancreaticoduodenectomy omental flaps periampullary neoplasms

Effect of interactions of two holes on tensile behavior of patch repaired carbon/epoxy woven laminates

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Defence Technology（防务技术） 2023年第3期21卷 88-93页

作者： Gursahib singh Bhatia Arockiarajan A. Department of Applied Mechanics Indian Institute of Technology Madras600036ChennaiIndia

The conventional case of patch repair involves bonding a patch over single damage/hole in the *** work investigates the effect of interaction of two holes on the tensile behavior patch repaired carbon epoxy woven *** specimens of[0°/45°/45°/0°]laminates were repaired with adhesively bonded two-ply[45°]2external *** different cases of drilled specimens were produced with different hole arrangements *** with single central hole(SH),with two holes aligned along the longitudinal axis(LH)and with two holes along transverse axis(TH).The two-hole specimens were repaired with two different types,*** large patches(SP)and with the two smaller patches(DP)of combined bonding area equal to the single large *** image correlation(DIC)was employed to capture strain *** results reveal the difference in the load transfer through the patches depending upon the arrangement of *** TH repaired specimen exhibit significant load recovery(SP-32.75%,DP-34.62%)while the LH specimens result in very marginal(SP-6.11%,DP-4.10%)recovery compared to their drilled *** TH specimen failed by crack growing through both the holes beneath the patch,while the LH specimens failed by the failure through only one *** use of single large patch over multiple holes and multiple small patches individually over each hole has no significant influence on load recovery.

关键词： crack patch behavior