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Microstructure and Mechanical properties of Friction Stir Lap Welded Aluminum Alloy AA2014

Journal of Materials Science & Technology 2012年第5期28卷 414-426页

作者： S. Babu G.D. Janaki ram p.V. Venkitakrishnan G. Madhusudhan Reddy K. prasad Rao Dept. of Metallurgical and Materials Engineering Indian Institute of Technology Madras Chennai India Liquid propulsion Systems Centre Indian Space Research Organisation Tiruvananthapuram India Defence Metallurgical Research Laboratory Hyderabad India

Friction stir lap welds were produced in 3 mm thick Alclad sheets of Al alloy 2014-T4 using two different tools （with triangular and threaded taper cylindrical pins）. The effects of tool geometry on weld microstructure, lap-shear performance and failure mode were investigated. The pin profile was found to significantly influence the hook geometry, which in turn strongly influenced the joint strength and the failure mode. Welds produced in alloy 2014-T4 Alclad sheets by using triangular and threaded taper cylindrical tools exhibited an average lap-shear failure load of 16.5 and 19.5 kN, respectively, while the average failure load for standard riveted joints was only 3.4 kN. Welds produced in alloy 2014-T6 Alclad sheets and in alloy 2014-T4 bare sheets （i.e., no Alclad） were comparatively evaluated with those produced in alloy 2014-T4 Alclad sheets. While the welds made （with threaded taper cylindrical tool） in T6 and T4 conditions showed very similar lap-shear failure loads, the joint efficiency of the welds made in T6 condition （43%） was considerably lower （because of the higher base material strength） than those made in T4 condition （51%）. The Alclad layers were found to present no special problems in friction stir lap welding. Welds made with triangular tool in alloy 2014-T4 Alclad and bare sheets showed very similar lap-shear failure loads. The present work provides some useful insights into the use of friction stir welding for joining Al alloys in lap configuration.

关键词： Aluminum alloys Friction stir welding Lap joints Lap-shear testing

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Electron paramagnetic Resonance and Optical Absorption of VO2＋ Doped Bis （glycinato） Mg （II） Monohydrate Single Crystals

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Chinese physics Letters 2010年第1期27卷 238-241页

作者： prashant Dwivedi ram Kripal Santwana Shukla Department of physics Kali Charan Nigam Institute of Technology Banda (U.P.) 210001 India EpR Laboratory Department of Physics University of Allabad Allahabad 211002 India

We investigate the electron paramagnetic resonance （EpR） of VO2＋ ions in bis （glycinato） Mg （II） monohydrate single crystals at room temperature. Detailed EpR analysis indicates the presence of only one VO2＋ site. The vanadyl complexes are found to take up the substitutional position. The angular variation of the EpR spectra in three planes a＊b, bc and ca＊ are used to determine principal g and A tensors. The values of spin Hamiltonian parameters are gx= 2.1447× 10-4, gy= 1.9974×10-4, gz= 1.9131×10-4, Ax= 49×10-4, Ay= 60×10-4, Az= 82×10-4 cm-1. The optical absorption study is also carried out at room temperature and absorption bands are assigned to various transitions. The theoretical band positions are obtained using energy expressions and a good agreement is found with the experimental data. By correlating EpR and optical data, different molecular orbital coefficients are evaluated and the nature of bonding in the crystal is discussed.

关键词： Temperature Data Uses Absorption Timing Time

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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;pported deaths in three clinical trials were 75,and there were 24 graft rejections in two *** All clinical trials reported significant proportions of antimicrobial-resistant microor

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

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Ceria in halogen chemistry

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Chinese Journal of Catalysis 2020年第6期41卷 915-927页

作者： Matthias Scharfe Guido Zichittella Vladimir paunovic Javier pérez-ramírez Institute for Chemical and Bioengineering Department of Chemistry and Applied BiosciencesETH ZurichVladimir-Prelog-Weg 18093 ZurichSwitzerland

Halogen chemistry constitutes an essential part in the industrial production of polymers and gains increasing attention as an attractive strategy to activate light alkanes that constitute natural gas. CeO2-based catalysts offer an exciting potential for advances in hydrogen halide recovery that enables a high efficiency of halogen-based processes for activation of small molecules. This review provides an overview of recently developed ceria-based catalysts in the context of polymer industry(polyvinyl chloride, polyurethanes, and polycarbonates) and activation of light hydrocarbons for natural gas upgrading. In addition, mechanistic insight and the challenges of ceria catalysts are provided, aiding the design of future catalytic materials and applications.

关键词： CeO2 Hydrogen halides Ethylene Alkanes Selective natural gas upgrading Oxidation Oxyhalogenation Vinyl chloride

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A Comprehensive Review on Oxygen Reduction Reaction in Microbial Fuel Cells

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Journal of Renewable Materials 2022年第3期10卷 665-697页

作者： pooja Dange Nishit Savla Soumya pandit rambabu Bobba Sokhee p.Jung piyush Kumar Gupta Mohit Sahni ram prasad Amity Institute of Biotechnology Amity UniversityMumbai410206India Department of Life Sciences School of Basic Sciences and ResearchSharda UniversityGreater Noida201306India Department of physics Southern University and A&M CollegeBaton Rouge70813USA Department of Environment and Energy Engineering Chonnam National UniversityGwangju61186Korea Department of physics School of Basic Sciences and ResearchSharda UniversityGreater Noida201306India Department of Botany Mahatma Gandhi Central UniversityBihar845401India

The focus of microbial fuel cell research in recent years has been on the development of materials,microbes,and transfer of charges in the system,resulting in a substantial improvement in current density and improved power *** cathode is generally recognized as the limiting factor due to its high-distance proton transfer,slow oxygen reduction reaction(ORR),and expensive *** heterogeneous reaction determines power gen-eration in *** comprehensive review describes-recent advancements in the development of cathode mate-rials and catalysts associated with *** recent studies indicated the utilization of different metal oxides,the ferrite-based catalyst to overcome this *** studies conclude that some cathode materials,in parti-cular,graphene-based conductive polymer composites with non-precious metal catalysts provide substantial ben-efits for sustainable development in the field of ***,it also highlights the potentiality to replace the conventional platinum air cathode for the large-scale production of the next generation of *** was evi-dent from the experiments that cathode catalyst needs to be blended with conductive carbon materials to make cathode conductive and efficient for *** review discusses various antifouling strategies for cathode biofoul-ing and its effect on the MFC ***,it also depicts cost estimations of various catalysts essential for further scale-up of MFC technology.

关键词： Cathode catalyst microbial fuel cell(MFC) nanomaterials oxygen reduction reaction(ORR) biofouling biocathode

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Influence of cerium ions on structure-dependent magnetic properties of Ba-Sr M-type hexaferrite nanocrystals

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Journal of Rare Earths 2024年第2期42卷 364-372,I0005页

作者： ram A.pawar Sunil M.patange p.M.Dighe Sher Singh Meena Abdullah GAl-Sehemi Mehboobali pannipara Santosh S.Jadhav Department of physics ArtsCommerce and Science CollegeAhmednagar413711MaharashtraIndia Department of physics Shri Krishna MahavidyalayaGunjotiDistOsmanabad413606MaharashtraIndia padmashri Vikhe patil College of Arts Science and CommercePravaranagarA/P.Loni(Kd)Tal.RahataDistAhmednagar413713MaharashtraIndia Solid State physics Division Bhabha Atomic Research CentreMumbai400085MaharashtraIndia Department of Chemistry King Khalid UniversityAbha61413Saudi Arabia Department of physics D.S.M's ArtsCommerce and Science CollegeJintur431509MaharashtraIndia

The present study is a systematic effort to investigate the structure-sensitive magnetic parameters of Ce^(3+) substituted Ba-Sr hexaferrite nanocrystals chemically formulated as Ba_(0.5)Sr_(0.5)Ce_(x)Fe_(12-x)O_(19) where x=0.0-0.2 with Δx=*** hexaferrite powders were prepared using the sol-gel self-ignition route and structurally characterized by means of powder X-ray diffraction and Fourier transform infrared *** creation of the M-type hexaferrite phase within the synthesized samples was revealed from the Rietveld refinement of the X-ray *** occurrence of a secondary phase of CeO_(2) was revealed within the hexaferrites for the substitution,x> *** refined X-ray diffraction data were utilized to compute the lattice parameters,X-ray density,and lattice parameter *** crystal structure plotted from the refined XRD data reveals the occupancy of the ions at different lattice *** XpS data of the hexaferrite were analyzed to confirm the oxidation states of the constituent *** nanocrystalline nature of the hexaferrites was revealed from the crystallite sizes calculated using Scherer's *** analysis of FTIR spectra confirms that only a fraction of Ce^(3+)accommodated in the lattice and the remaining Ce content reside in the form of the CeO_(2) *** morphology of the hexaferrites was analyzed from the FESEM profiles of the ferrite *** magnetic behavior study was performed by analyzing the Curie temperature,hysteresis loops,and hyperfine interactions by means of susceptibility,V.S.M,and Mossbauer spectroscopy,*** hexaferrites with increasing coercivity,decreasing saturation magnetization,and decreasing Curie temperature are reported in the *** substituted Ce^(3+)ions inhibit the grain growth and create lattice imperfections giving rise to hexaferrites with tuned magnetic parameters suitable for different applications.

关键词： Ba-Sr hexaferrite Ce^(3+)substitution XpS Saturation magnetization Coercivity M?ssbauer spectroscopy

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Trends in the prevalence of obesity among young Thai men and associated factors:From 2009 to 2016

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Military Medical Research 2019年第4期6卷 299-307页

作者： panadda Hatthachote ram Rangsin Mathirut Mungthin Boonsub Sakboonyarat Department of physiology Phramongkutklao College of MedicineBangkok 10400Thailand Department of Military and Community Medicine Phramongkutklao College of MedicineBangkok 10400Thailand Department of pharmacology Phramongkutklao College of MedicineBangkok 10400Thailand

Background:The prevalence of obesity has been increasing in both males and females *** Thailand,the National Health Examination Surveys reported that the prevalence of obesity(body mass index(BMI)≥30 kg/m^2)among Thai male adults aged 20–59 years increased from 1.7%in 1991 to 6.8%in *** has been confirmed to lead to health problems,including noncommunicable *** the present study,we report trends in the prevalence of obesity among new conscripts from 2009 to *** also investigated the associated factors of ***:Serial cross-sectional studies were conducted from 2009 to 2016 among male Royal Thai Army(RTA)conscripts whose weight and height had been measured to determine BMI after being *** subject completed a detailed risk factor *** was defined as BMI≥30 kg/***:A total of 26,540 young Thai males conscripted into the RTA were included in this *** prevalence of obesity was 2.2%in 2009,3.4%in 2010,2.5%in 2011,2.9%in 2012,3.4%in 2013,4.4%in 2014,5.0%in 2015,and 4.8%in 2016(p for trendpendent risk factors for obesity were coming from the north central and south regions compared with the northeast,higher education level,indoor occupation and no regular ***:Our data emphasized that obesity constitutes a serious problem among young Thai *** could apply these findings in military units to other groups at any *** exercise should be provided to young adults and other age groups to slow the process of obesity,so that associated complications,especially noncommunicable diseases,will cease.

关键词： Trends prevalence Obesity Young men Thailand The Royal Thai Army

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Graphene-based bipolar plates for polymer electrolyte membrane fuel cells

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Frontiers of Materials Science 2019年第3期13卷 217-241页

作者： ram Sevak SINGH(El) Anurag GAUTAM Varun RAI Department of physics O P Jindal UniversityRaigarhChhattisgarh 496109India Department of Chemistry O P Jindal UniversityRaigarhChhattisgarh 496109India Department of Materials Science and Engineering National University of SingaporeSingapore 117576Singapore

Bipolar plates(Bps)are a major component of polymer electrolyte membrane fuel cells(pEMFCs).Bps play a multifunctional character within a pEMFC *** is one of the most costly and critical part of the fuel cell,and hence the development of efficient and cost-effective Bps is of much interest for the fabrication of next-generation pEMFCs in *** to high electrical conductivity and chemical inertness,graphene is an ideal candidate to be utilized in *** paper reviews recent advances in the area of graphene-based Bps for pEMFC *** aspects including the momentous functions of Bps in the pEMFC,favorable features of *** Bps,performance evaluation of various reported Bps with their advantages and disadvantages,challenges at commercial level products and future prospects of frontier research in this direction are extensively documented.

关键词： graphene bipolar plate polymer electrolyte membrane fuel cell proton exchange membrane fuel cell

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Integrin binding peptides facilitate growth and interconnected vascular-like network formation of rat primary cortical vascular endothelial cells in vitro

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Neural Regeneration Research 2023年第5期18卷 1052-1056页

作者： ram Kuwar Xuejun Wen Ning Zhang Dong Sun Department of Anatomy and Neurobiology Medical College of Virginia CampusVirginia Commonwealth UniversityRichmondVAUSA Department of Chemical and Life Science Engineering College of EngineeringVirginia Commonwealth UniversityRichmondVAUSA Department of Biomedical Engineering College of EngineeringVirginia Commonwealth UniversityRichmondVAUSA

Neovascularization and angiogenesis in the brain are important physiological processes for normal brain development and repair/regeneration following insults. Integrins are cell surface adhesion receptors mediating important function of cells such as survival, growth and development during tissue organization, differentiation and organogenesis. In this study, we used an integrin-binding array platform to identify the important types of integrins and their binding peptides that facilitate adhesion, growth, development, and vascular-like network formation of rat primary brain microvascular endothelial cells. Brain microvascular endothelial cells were isolated from rat brain on post-natal day 7. Cells were cultured in a custom-designed integrin array system containing short synthetic peptides binding to 16 types of integrins commonly expressed on cells in vertebrates. After 7 days of culture, the brain microvascular endothelial cells were processed for immunostaining with markers for endothelial cells including von Willibrand factor and platelet endothelial cell adhesion molecule. 5-Bromo-2′-dexoyuridine was added to the culture at 48 hours prior to fixation to assess cell proliferation. Among 16 integrins tested, we found that α5β1, αvβ5 and αvβ8 greatly promoted proliferation of endothelial cells in culture. To investigate the effect of integrin-binding peptides in promoting neovascularization and angiogenesis, the binding peptides to the above three types of integrins were immobilized to our custom-designed hydrogel in three-dimensional(3 D) culture of brain microvascular endothelial cells with the addition of vascular endothelial growth factor. Following a 7-day 3 D culture, the culture was fixed and processed for double labeling of phalloidin with von Willibrand factor or platelet endothelial cell adhesion molecule and assessed under confocal microscopy. In the 3 D culture in hydrogels conjugated with the integrin-binding peptide, brain microvascular endothelial c

关键词： 3D culture angiogenesis brain microvascular endothelial cells hydrogel integrins platelet endothelial cell adhesion molecule(pECAM-1) vascular endothelial growth factor(VEGF) vascularization

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Exploring the unique biophysical characteristics and ecosystem services of mountains: A review

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Journal of Mountain Science 2024年第11期21卷 3584-3597页

作者： Gebrekidan Worku TEFERA ram L.RAY Amare BANTIDER Cooperative Agricultural Research Center College of AgricultureFood and Natural ResourcesPrairie View A&M UniversityPrairie ViewTX 77446USA Center for Food Security Studies Addis Ababa UniversityAddis AbabaP.O.Box 1145Ethiopia Water and Land Resources Center Addis Ababa UniversityAddis AbabaP.O.Box 1145Ethiopia

Mountains are unique terrestrial ecosystems characterized by distinct physiography,biological diversity,and socio-economic *** ecosystems provide numerous essential goods and services to communities within and beyond the *** their significance,comprehensive studies that thoroughly characterize the ecosystem services of mountains are *** research is crucial to advance scientific understanding of mountain characteristics and ecosystem *** study investigates mountain regions’unique characteristics and ecosystem services using global datasets such as the *** Survey(USGS),the Global Mountain Biodiversity Assessment(GMBA),NASA EARTHDATA,and other relevant databases and literature *** focus was to explore unique physiographic and socio-economic characteristics and ecosystem services provided by *** results indicate that mountain ecosystems are pivotal in offering provisional,regulatory,and supporting ecosystem services on *** their limited geographical area,these ecosystems supply substantial amounts of freshwater to communities living within and downstream of mountainous ***,mountain ecosystems serve as global biodiversity hotspots,harboring a significant proportion of the world's ***,mountain ecosystems face numerous natural and anthropogenic challenges,including climate change,habitat destruction,and resource *** efforts towards sustainable mountain development are *** scientific research and targeted policy measures are essential to address these challenges,protect mountain biodiversity,and ensure the continuous provision of vital ecosystem services.

关键词： Mountains Ecosystems services Biodiversity Freshwater Cultural services

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