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Journal of Advanced Dielectrics 2015年第4期5卷 1-9页

作者： Radheshyam Rai Poonam Kumari m.a.valente School of Physics Shoolini UniversitySolan173212HPIndia Departamento de Fisica i3nUniversidade de AveiroCampus Universitario de Santiago3810-193 AveiroPortugal

In this paper,we investigated the influence of rare earth(RE=La and Gd)doped Ba_(0.9575)RE_(0.04)Ca_(0.0025)Ti_(0.80685)mn_(0.002475)Nb_(0.002475)Zr_(0.1782)O_(3)(BCTmNZ)ceramics were fabricated by using a conventional solid state reaction *** doping effects of La and Gd on the structural and magnetic properties were *** structural pattern of the ceramic samples were investigated by X-ray diffraction and the results indicated that both samples shows an orthorhombic structure with pure *** and crystalline size values for Gd and La doped were 0.31-0.33%and 0.154-0.181μm,*** room temperature hysteresis loops were obtained by using a vibrating sample *** doped ceramic showed the higher value of mag-netization i.e.,0.369μB/*** compared to Gd doped BLTmNZ ceramics.

关键词： Ceramics X-ray diffraction lttice strain magnetic properties

Dielectric,electrical conduction and magnetic properties of multiferroic Bi_(0.8)Tb_(0.1)Ba_(0.1)Fe_(0.9)Ti_(0.1)O_(3)perovskite compound

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Journal of Advanced Dielectrics 2017年第5期7卷 47-56页

作者： Poonam Kumari Radheshyam Rai Seema Sharma m.a.valente School of Physics and materials Science Shoolini University 173212 Solan H.P.India Ferroelectric Research Laboratory Department of Physics A N CollegePatna 800013India Departamento de Fisica I3NUniversidade de Aveiro Campus Universitario de Santiago 3810193 AveiroPortugal Department of Physics ACBSEternal University Baru Sahib 173101H.P.India

This work focuses on the structural,electrical and magnetic properties of Bi_(0.8)Tb_(0.1)Ba_(0.1)Fe_(0.9)Ti_(0.1)O_(3)ceramics,fabricated by solid state reaction *** forms of the samples at RT exhibited perovskite phase through the hexagonal structure at room *** studies of the materials with frequency at different temperatures(25-400℃)exhibit two dielectric anomalies,first at 175℃(ferroelectric-ferroelectric transition)and second at around 320℃(ferroelectric-paraelectric transition).The Curie temperature moved towards the low side temperature with the increase in *** less value of activation energy got for these samples could be attributed to the influence of electronic contribution to the conductivity.A significant change in the magnetic studies was observed for Bi_(0.8)Tb_(0.1)Ba_(0.1)Fe_(0.9)Ti_(0.1)O_(3) *** impedance analysis confirms the non-Debye type nature of the ceramic and relaxation frequency moved to a higher *** Nyquist plot and conductivity studies showed the NTCR behavior of *** highest magnetization field was found at temperature-268.15℃.

关键词： Lead-free ceramics X-ray difraction(XRD) phase transitions electrical conduction magnetic properties multiferroics

magnetic and specific heat studies of the frustrated Er_2mn_2O_7 compound

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Journal of Rare Earths 2013年第1期31卷 54-59页

作者： N.Ben Amor m.Bejar E.Dhahri m.a.valente P.Lachkar E.K.Hlil Laboratory of Applied Physics Faculty of Sciences of SfaxBP 1171University of Sfax I3N and Physics Department University of Aveiro mCmF Néel InstitutCNRS25 avenue des MartyrsBuilding FBP 16638042 Grenoble cedex 9France mCBT Institut NéelCNRS25 avenue des MartyrsBuilding EBP 16638042 Grenoble cedex 9France

A new Erzmn207 compound was synthesized by the ceramic method and its crystal structure was characterized LJsing powder X-ray diffraction （XRD） and observed by scanning electron microscopy （SEm）. The magnetic properties were investigated using a BS2 magnetometer and the heat capacity was studied using a quantum design （PPmS）. The structural study revealed that this compound was monophasic and crystallized in the monoclinic system with the P2/m space group. magnetization measurements were carried out in the temperature range of 1.8-200 K under an applied magnetic field of 0.05 T. A crossover from a room temperature para- magnetic phase to an antiferromagnetic one at low temperature was detected from the magnetic study. The magnetic susceptibility, in the paramagnetic region above 40 K, was found to present a simple Curie-Weiss type behavior. From the specific heat （G,） measurements in magnetic fields up to 5 T, we noted the presence of a wide peak characteristic of a second order magneto-structural transition.

关键词： magnetic frustration magnetic phase transition specific heat rare earths

FERROELECTRIC AND mAGNETIC PROPERTIES OF PEROVSKITE STRUCTURED Bi_(1-x-y)Gd_(x)Ba_(y)Fe_(1-y)Ti_(y)O_(3)mAGNETOELECTRIC CERAmICS

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Journal of Advanced Dielectrics 2011年第2期1卷 257-267页

作者： RADHESHYAm RAI IGOR BDIKIN m.a.valente ANDREI L.KHOLKIN Department of Ceramics and Glass Engineering and CICECO University of Aveiro 3810-193 AveiroPortugal Centre for mechanical Technology and Automation University of Aveiro 3810-193AveiroPortugal Department of Physics University of Aveiro 3810-193 AveiroPortugal

Ternary solid solutions of BiFeO_(3),GdFeO_(3)and BaTiO_(3)have been prepared by solid-state reaction *** properties of these ceramics have been characterized in the tem-perature range between room temperature and 673 K and magnetic properties between 5 K and *** the understanding of the multiferroic property,the relation between the crystal structures,magnetic transition and ferroelectric transitions with increasing temperature have been *** ceramic samples show single perovskite *** Ba content exceeds 0.2 wt%,the sintering ability is weakened and the phase structure of Bi_(1-x-y)Gd_(x)Ba_(y)Fe_(1-y)Ti_(y)O_(3)(with x=0.2 and y=0.1,0.2,0.3,0.4,0.5)solid solution changes from rhombohedral to tetragonal *** maximum ferroelectric transition temperature(T_(c))of this system was in the range 154-165℃with the dielectric constant peak of 6000 for y=0.5 at 100 ***-saturated piezoresponse hysteresis loops were observed for all compositions indicating room temperature *** increasing Ba content(up to 0.3 wt%)the remanent magnetization m,increased and the coercive magnetic field decreased.

关键词： Ceramics X-ray difraction dielectric properties electrical properties magnetic properties

Structural,dielectric and magnetic properties of Pr-,Tb-and Dy-doped(Bi_(0.95)RE_(0.05))(Fe_(0.95)mn_(0.05))O_(3) ceramics synthesized by solid-state reaction method

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Journal of Advanced Dielectrics 2013年第4期3卷 55-61页

作者： Radheshyam Rai Shweta Thakur m.a.valente Andrei L.Kholkin School of Physics Shoolini University SolanHP 173229India Departamento de Fisica I3NUniversidade de Aveiro Campus Universitario de Santiago 3810-193 AveiroPortugal Department of Ceramics and Glass Engineering and CICECO University of Aveiro 3810-193 AveiroPortugal

The multiferroic(Bi_(0.95)RE_(0.05))(Fe_(0.95)mn_(0.05))O_(3)(where RE=Pr,Tb and Dy)has been synthesized using solid-state reaction *** of Pr,Tb and Dy substitution on the structure,electrical and ferroelectric properties of(Bi_(0.95)RE_(0.05))(Fe_(0.95)mn_(0.05))O_(3) samples have been studied by performing X-ray diffraction,dielectric measurements and magnetic *** crystal structure of the ceramic samples have a monoclinic *** vibrating sample magnetometer(VSm)measurement shows a significant change in the magnetic properties of Pr-,Tb-and Dy-doped(Bi_(0.9)RE_(0.05))(Fe_(0.95)mn_(0.05))O_(3).It is seen that coercive field(Hc)and remanent magnetization(mr)increases for Pr but decreases for Dy and Tb.

关键词： Ferrites X-ray diffraction dielectric properties electrical properties magnetic properties

Dielectric and magnetic properties of Ba-,La-and Pb-doped Bi_(0.8)Gd_(0.1)m_(0.1)Fe_(0.9)Ti_(0.1)O_(3) perovskite ceramics

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Journal of Advanced Dielectrics 2014年第2期4卷 26-34页

作者： Radheshyam Rai m.a.valente Anoop Kumar Shukla Seema Sharma Andrei L.Kholkin School of Physics Shoolini UniversitySolanHP 173229India Departamento de Fisica I3NUniversidade de Aveiro Campus Universitario de Santiago3810-193 AveiroPortugal Department of Physics Amity Institute of Applied Sciences Amity University Uttar PradeshG.B.NagarUP 201301India Ferroelectric Research Laboratory Department of Physics A N CollegePatna 800013India Department of Ceramics and Glass Engineering and CICECO University of Aveiro 3810-193 AveiroPortugal

The multiferroic Bi_(0.8)Gd_(0.1)m_(0.1)Fe_(0.9)Ti_(0.1)O_(3),(where m=Ba(DB),La(DL)and Pb(DP))has been synthesized by using solid-state reaction *** of Ba,La and Pb substitution on the structure,electrical and ferroelectric properties of Bi_(0.8)Gd_(0.1)m_(0.1)Fe_(0.9)Ti_(0.1)O_(3) samples have been studied by performing X-ray diffraction,dielectric and magnetic *** crystal structures of the ceramic samples have a tetragonal *** vibrating sample magnetometer(VSm)measurement shows a significant change in the magnetic properties of Ba-doped Bi_(0.8)Gd_(0.1)m_(0.1)Fe_(0.9)Ti_(0.1)O_(3) as compared to La-and Pb-doped *** is seen that coercive field(HC)and remanent magnetization(mR)increases with Ba-doped ceramics but decreases for La-and Pbdoped ceramics.

关键词： multiferroic X-ray diffraction dielectric properties electrical properties magnetic properties

The effectiveness of different wear indicators in quantifying wear on railway wheels of freight wagons

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Railway Engineering Science 2024年第3期32卷 307-323页

作者： Philipe Augusto de Paula Pacheco m.magelli matheus valente Lopes Pedro Henrique Alves Correa N.Zampieri N.Bosso Auteliano Antunes dos Santos Federal Institute of the Southeast of minas Gerais(IF Sudeste mG) Técnico PanamáStreet 45Santos DumontMG 36246-311Brazil Railway Laboratory(Lafer) Universidade Estadual de Campinas(UNICAMP)Mendeleyev Street 200CampinasSP 13083-872Brazil Department of mechanical and Aerospace Engineering Politecnico Di TorinoC.so Duca degli Abruzzi 2410129 TurinItaly

Railway infrastructure relies on the dynamic interaction between wheels and rails;thus,assessing wheel wear is a critical aspect of maintenance and *** paper focuses on the wheel-rail wear indicator T-gamma(Tγ).Amidst its use,it becomes apparent that Tγ,while valuable,fails to provide a comprehensive reflection of the actual material removal and actual contact format,which means that using only Tγas a target for optimization of profiles is not *** this work,three different freight wagons are evaluated:a meter-gauge and a broad-gauge heavy haul vehicles from South American railways,and a standard-gauge freight vehicle operated in Europe,with different axle loads and dissimilar new wheel/rail *** vehicles are subjected to comprehensive multibody simulations on various *** simulations aimed to elucidate the intricate relationship between different wear indicators:Tγ,wear index,material removal,and maximum wear depth,under diverse curves,non-compensated lateral accelerations(A_(nc)),and *** findings showed a correlation of 0.96 between Tγand wear depth and 0.82 between wear index and material removed for the outer *** the results,the Tγis better than the wear index to be used when analyzing wear depth while the wear index is more suited to foresee the material *** results also show the low influence of A_(nc)on wear index and Tγ.By considering these factors together,the study aims to improve the understanding of wheel-rail wear by selecting the best wear analysis approaches based on the effectiveness of each parameter.

关键词： Wear index Wear volume Wear modeling Dynamic simulation

Zinc deficiency in patients with chronic pancreatitis

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World Journal of Gastroenterology 2019年第5期25卷 600-607页

作者： miroslav Vujasinovic AleksANDra Hedstr?m Patrick maisonneuve Roberto valente Henrik von Horn J-matthias L?hr Stephan L Haas Department for Digestive Diseases Karolinska University Hospital Division of Epidemiology and Biostatistics IEO European Institute of Oncology IRCCS Department for Digestive Diseases Sapienza University of Rome Division of Clinical Chemistry Department of Molecular Medicine and Surgery Karolinska Institutet Karolinska University Hospital Department of Clinical Science Intervention and Technology (CLINTEC)Karolinska Institute

BACKGROUND Zinc is a key element in numerous proteins and plays an important role in essential cell functions such as defense against free radicals and DNA damage repair. Chronic pancreatitis(CP) is a chronic inflammation with progressive fibrosis of pancreas ultimately resulting in pancreatic exocrine insufficiency(PEI),which is associated with malnutrition. Studies analyzing zinc levels in patients with CP are sparse and lead to conflicting *** To investigate serum zinc levels in patients with CP of various *** Between October 2015 and march 2018, patients with a diagnosis of CP were identified and recruited from the Pancreatic Outpatient Clinic at the Karolinska University Hospital in Stockholm, Sweden. Demographic, clinical and laboratory data were analyzed. Etiology of CP was determined according to the mANNHEIm classification system into the following etiological subcategories:alcohol consumption, nicotine consumption, hereditary factors, efferent pancreatic duct factors and immunological factors. Pancreatic exocrine function was defined as normal(fecal elastase 1 > 200 μg/g), mildly reduced(100-200μg/g) and severely reduced(fecal elastase 1 mol/L) was present in 39(26.0%) of patients: 22 females and 17 males. In the group of patients with zinc deficiency, 76.7% of patients had an exocrine pancreatic insufficiency(FE-1 mpared to patients 0.002]. Smoking and number of packyears were additionally associated with low zinc levels. The risk of zinc deficiency in current smokers and smokers with ≥ 20 pack-years was approximately three times higher

关键词： Zinc Pancreas Pancreatic exocrine insufficiency Chronic pancreatitis malnutrition

Reversible acetylation regulates vascular endothelial growth factor receptor-2 activity

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Journal of molecular Cell Biology 2014年第2期8卷 116-127页

作者： Annalisa Zecchin Lucia Pattarini maria Ines Gutierrez miguel mano Antonello mai Sergio valente mike P. myers Sergio Pantano mauro Giacca molecular medicine Laboratory International Centre for Genetic Engineering and Biotechnology (ICGEB) Trieste Italy Istituto Pasteur-Fondazione cenci-Bolognetti Dipartimento di Chimica e Tecnologie del Farmaco Sapienza Universita' di Roma Rome Italy Protein Networks Laboratory International Centre for Genetic Engineering and Biotechno[ogy (ICGEB) Trieste Italy Biomolecular Simulations Group Institut Pasteur de Montevideo' Montevideo Uruguay U932 Immunity and Cancer Integrative Biology of Human Dendritic Cells and T Cells Laboratory Institute Curie Paris France

The tyrosine kinase receptor vascular endothelial growth factor receptor 2 （VEG FR2） is a key regulator of angiogenesis. Here we show that VEGFR2 is acetylated in endothelial cells both at four lysine residues forming a dense cluster in the kinase insert domain and at a single lysine located in the receptor activation loop. These modifications are under dynamic control of the acetyltransferase p300 and two deacetyiases HDAC5 and HDAC6. We demonstrate that VEGFR2 acetylation essentially regulates receptor phosphorylation. In par- ticular, VEGFR2 acetylation significantly alters the kinetics of receptor phosphorylation after ligand binding, allowing receptor phos- phoryiation and intraceUular signaling upon proLonged stimulation with VEGF. molecular dynamics simulations indicate that acetylation of the lysine in the activation loop contributes to the transition to an open active state, in which tyrosine phosphorylation is favored by better exposure of the kinase target residues. These findings indicate that post-translational modification by acetyiation is a critical mechanism that directLy affects VEGFR2 function.

关键词： acetylation angiogenesis p300 phosphorylation vascular endothelial growth factor

Event-based hydrology and sedimentation in paired watersheds under commercial eucalyptus and grasslands in the Brazilian Pampa biome

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International Soil and Water Conservation Research 2021年第2期9卷 180-194页

作者： Ederson Diniz Ebling Jose miguel Reichert Jhon Jairo Zuluaga Pelaez miriam Fernanda Rodrigues mirian Lago valente Rosane Barbosa Lopes Cavalcante Paolo Reggiani Raghavan Srinivasan Soils Department Universidade Federal de Santa MariaAvenida Roraima1000 Bairro CamobiSanta MariaRS97105-900Brazil Corporacion Colombiana de Investigacion Agropecuaria(AGROSAVIA) Centro de Investigacion NataimaEspinalColombia CmPC Celulose Riograndense Rua Sao Geraldo1680GuaibaRS92500-000Brazil Department of Civil Engineering University of SiegenPaul Bonatz Strasse 9-11Siegen D57068Germany Department of Ecology and Conservation Biology Texas A&M University(TAMU)534 John Kimbrough Blvd.Room 305College StationTX77843-2120USA Current address:Instituto Tecnologico Vale.Rua Boaventura da Silva 955UmarizalBelemPABrazil.

Ecological and hydrological impacts are expected when watersheds are under commercial *** this study we evaluated event-based hydrology and sedimentation in paired watersheds under commercial eucalyptus and grasslands ***,suspended sediment concentration,and sediment production were measured and simulated with the Limburg Soil Erosion model(LISEm)in paired hydrographic watersheds located in southern Brazil;one occupied with 7-years old Eucalyptus saligna plantation(forest watershed-FW;0.83 km^(2))and another Pampa biome with native and exotic grasses used for beef cattle production(grassland watershed-GW;1.10 km^(2)).The effect of rainfall on hydrological and sedimentological variables was more evident in GW compared with *** shape of the hydrograph was steepest in GW,with rapid,marked increase and decrease in flow during *** parameters changed for model calibration in FW and GW were soil saturated hydraulic conductivity,initial soil moisture,and manning roughness coefficient,whereby the statistical performance was classified as good(NSE>0.75).Fourteen events different from those used in the calibration process were validated for FW and GW,with NSE index classified as“good”and“very good”for *** study shows limitations of LISEm in calibrating and validating the sediment yield for individual events due to the spatial variability of factors controlling soil *** validated modeling results of this study may be applied in simulating soil and crop scenarios in watersheds cultivated with commercial forest and grassland for grazing.

关键词： Southern grasslands Paired watersheds Runoff Erosion LISEm