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Energy transfer and luminescent properties of Tb^(3+)and Tb^(3+),Yb^(3+)doped CNgg phosphors

Journal of Rare Earths 2022年第9期40卷 1445-1453,I0004页

作者： S.Hau g.stanciu D.Avram L.gheorghe C.gheorghe National Institute for Laser Plasma and Radiation PhysicsSolid State Quantum Electronics Laboratory409 Atomistilor StreetP.O.Box MG-36Magurele077125IlfovRomania

In this work,calcium niobium gallium garnet(Ca_(3)Nb_(1.6875)ga_(3.1875)O_(12)-CNgg)ceramic samples singledoped with Tb^(3+)and co-doped with Tb^(3+)and Yb^(3+)ions were sintered by the solid-state reaction *** structural characterization of the samples was carried out by X-ray diffraction *** optimal concentration of Tb^(3+)ions corresponding to the maximum luminescence in the green spectral range in CNgg:x at%Tb(x=0.1,0.5,1,2,3,4,and 5)was determined to be 4 at%.The timeresolved luminescence of the^(5)D_(4)level(Tb^(3+))in the CNgg:x at%Tb samples was analysed to explore the quenching mechanisms involved in the Tb^(3+)green ***-doped CNgg:4 at%Tb,y at%Yb(y=0.5,2,4,6,8,and 10)ceramics were prepared and *** is shown that CNgg:4 at%Tb,y at%Yb phosphors exhibit intense green luminescence under ultra-violet(UV),visible(VIS),and near-infrared(NIR)excitation,thus demonstrating the presence of simultaneous down-conversion(DC)and upconversion(UC)*** dependence of the UC luminescence intensity on the diode laser pumping power was measured and the results indicate a two-photon process based on cooperative energy transfer(CET).Under UV excitation,the lifetime of the^(5)D_(4)(Tb^(3+))level slowly increases with increase of Yb^(3+)concentration,suggesting the energy transfer from Yb^(3+)to Tb^(3+)ions,while under NIR excitation,the lifetime of the^(5)D_(4)(Tb^(3+))level decreases with increase of Yb^(3+)ions concentration,indicating the presence of a strong energy transfer from Tb^(3+)to Yb^(3+)*** highest energy transfer efficiency ofη_(ET)≈42%was determined for the CNgg:4 at%Tb,10 at%Yb *** obtained results indicate that CNgg:(Tb^(3+),Yb^(3+))could be efficient new yellowish-green-emitting phosphors.

关键词： Phosphors Tb^(3+)and Tb^(3+)-Yb^(3+)luminescence properties Up-conversion Down-conversion Quantum cutting process Rare earths

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Matching DSIFT Descriptors Extracted from CSLM Images

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Engineering（科研） 2013年第10期5卷 199-202页

作者： Stefan g.stanciu Dinu Coltuc Denis E.Tranca george A.stanciu Center for Microscopy-Microanalysis and Information Processing University Politehnica of BucharestBucurestiRomania Light Microscopy and Screening Center Swiss Federal Institute of TechnologyZurichSwitzerland Electric Engineering Department Valahia University of TârgovisteTargovisteRomania

The matching of local descriptors represents at this moment a key tool in computer vision, with a wide variety of methods designed for tasks such as image classification, object recognition and tracking, image stitching, or data mining relying on it. Local feature description techniques are usually developed so as to provide invariance to photometric variations specific to the acquisition of natural images, but are nonetheless used in association with biomedical imaging as well. It has been previously shown that the matching of gradient based descriptors is affected by image modifications specific to Confocal Scanning Laser Microscopy (CSLM). In this paper we extend our previous work in this direction and show how specific acquisition or post-processing methods alleviate or accentuate this problem.

关键词： Local Features Local Descriptors Feature Matching SIFT CSLM

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Toward augmenting tip-enhanced nanoscopy with optically resolved scanning probe tips

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Advanced Photonics Nexus 2023年第2期2卷 48-64页

作者： Jeremy Belhassen Simcha glass Eti Teblum george A.stanciu Denis E.Tranca Zeev Zalevsky Stefan g.stanciu Avi Karsenty Jerusalem College of Technology Lev Academic CenterFaculty of EngineeringDepartment of Applied Physics/Electro-Optics EngineeringAdvanced Laboratory of Electro-OpticsJerusalemIsrael Bar-Ilan University Faculty of EngineeringRamat GanIsrael Nanotechnology Center for Research and Education Lev Academic CenterJerusalemIsrael Bar-Ilan University The Nanotechnology CenterRamat GanIsrael Politehnica University of Bucharest Center for Microscopy-Microanalysis and Information ProcessingBucharestRomania

A thorough understanding of biological species and emerging nanomaterials requires,among other efforts,their in-depth characterization through optical techniques capable of *** techniques based on tip-enhanced optical effects have gained tremendous interest over the past years,given their potential to obtain optical information with resolutions limited only by the size of a sharp probe interacting with focused light,irrespective of the illumination *** their popularity and number of applications is rising,tip-enhanced nanoscopy(TEN)techniques still largely rely on probes that are not specifically developed for such applications,but for atomic force *** limits their potential in many regards,e.g.,in terms of signal-to-noise ratio,attainable image quality,or extent of *** take the first steps toward next-generation TEN by demonstrating the fabrication and modeling of specialized TEN probes with known optical *** proposed framework is highly flexible and can be easily adjusted to be used with diverse TEN techniques,building on various concepts and phenomena,significantly augmenting their *** with known optical properties could potentially enable faster and more accurate imaging via different routes,such as direct signal enhancement or facile and ultrafast optical signal *** consider that the reported development can pave the way for a vast number of novel TEN imaging protocols and applications,given the many advantages that it offers.

关键词： tip-enhanced nanoscopy scanning probes COMSOL simulations nano-objects optical modeling

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Some Univalence Conditions for a general Integral Operator

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Chinese Annals of Mathematics,Series B 2012年第6期33卷 801-806页

作者： Laura stanciu Daniel BREAZ Department of Mathematics University of Pitesti Department of Mathematics University of Alba Iulia

The authors consider the classes of the univalent functions denoted by SH(β),SP and SP(α,β).On these classes,the univalence conditions for a general integral operator are studied.

关键词： Analytic function Integral operator Univalence condition generalSchwarz lemma

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Microchannel heat sink;Nanofluids;Entropy generation;Numerical analysis;Laminar flow

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Chinese Journal of Chemical Engineering 2019年第3期27卷 501-513页

作者： A.A.Alfaryjat A.Dobrovicescu D.stanciu Faculty of Mechanical Engineering and Mechatronics University Politehnica of BucharestSplaiul Independentei nr.313

Based on the Second Law of Thermodynamics, the entropy generation is studied for laminar forced convection flow of different nanoparticles(Al_2 O_3, CuO and SiO_2) mixed with water through a hexagon microchannel heat sink(HMCHS). The effects of different heat fluxes and Reynolds numbers on the entropy generation for different nanofluids, volume fractions and nanoparticles diameter are investigated. The heat flux is in the range of 125 to 500 kW·m^(-2) and the Reynolds numbers vary between 200 and 1500. The thermal, frictional and total entropy generations are calculated by integrating the volumetric rate components over the entire HMCHS. The results clearly show that the rise in the heat flux leads to an increase in the thermal entropy generation for nanofluids and pure water but they don't have any influence on the frictional entropy generation. Moreover, when the Reynolds number increases, the frictional entropy generation increases while the thermal entropy generation decreases. The results revealed that at low heat fluxes and high Reynolds numbers, pure water gives the lowest entropy generation, while at high heat flux the nanofluid has to be used in order to lower the overall irreversibility.

关键词： Microchannel heat sink Nanofluids Entropy generation Numerical analysis Laminar flow

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Stepping up after spinal cord injury:negotiating an obstacle during walking

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Neural Regeneration Research 2025年第7期20卷 1919-1929页

作者： Alain Frigon Charly g.Lecomte Department of Pharmacology-Physiology Faculty of Medicine and Health SciencesUniversitéde SherbrookeCentre de recherche du Centre Hospitalier Universitaire de SherbrookeSherbrookeQCCanada

Every day walking consists of frequent voluntary modifications in the gait pattern to negotiate *** spinal cord injury,stepping over an obstacle becomes *** over an obstacle requires sensorimotor transformations in several structures of the brain,including the parietal cortex,premotor cortex,and motor *** information and planning are transformed into motor commands,which are sent from the motor cortex to spinal neuronal circuits to alter limb trajectory,coordinate the limbs,and maintain *** spinal cord injury,bidirectional communication between the brain and spinal cord is disrupted and animals,including humans,fail to voluntarily modify limb trajectory to step over an ***,in this review,we discuss the neuromechanical control of stepping over an obstacle,why it fails after spinal cord injury,and how it recovers to a certain extent.

关键词： biomechanics locomotion neurophysiology obstacle negotiation spinal cord injury

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Update on adrenal insufficiency in patients with liver cirrhosis

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World Journal of gastroenterology 2013年第4期19卷 445-456页

作者： Anca Trifan Stefan Chiriac Carol stanciu "gr.T.Popa" University of Medicine and Pharmacy Institute of Gastroenterology and Hepatology"St.Spiridon" University Hospital

Liver cirrhosis is a major cause of mortality worldwide,often with severe sepsis as the terminal *** the last two decades,several studies have reported that in septic patients the adrenal glands respond inappropriately to stimulation,and that the treatment with corticosteroids decreases mortality in such *** cirrhosis and septic shock share many hemodynamic abnormalities such as hyperdynamic circulatory failure,decreased peripheral vascular resistance,increased cardiac output,hypo-responsiveness to vasopressors,increased levels of proinflammatory cytokines [interleukine(IL)-1,IL-6,tumor necrosis factor-alpha] and it has,consequently,been reported that adrenal insufficiency(AI) is common in critically ill cirrhotic *** may also be present in patients with stable cirrhosis without sepsis and in those undergoing liver *** term hepato-adrenal syndrome defines AI in patients with advanced liver disease with sepsis and/or other complications,and it suggests that it could be a feature of liver disease per se,with a dif-ferent pathogenesis from that of septic *** AI is the term given to inadequate cortisol response to *** recently,another term is used,namely "critical illness related corticosteroid insufficiency" to define "an inadequate cellular corticosteroid activity for the severity of the patient's illness".The mechanisms of AI in liver cirrhosis are not completely understood,although decreased levels of high-density lipoprotein cholesterol and high levels of proinflammatory cytokines and circulatory endotoxin have been *** prevalence of AI in cirrhotic patients varies widely according to the stage of the liver disease(compensated or decompensated,with or without sepsis),the diagnostic criteria defining AI and the methodology *** effects of corticosteroid therapy on cirrhotic patients with septic shock and AI are *** review aims to summarize the existing published information rega

关键词： Liver cirrhosis Adrenal insufficiency Septic shock Corticosteroid therapy

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Bioelectronic medicine in modulation of cortical spreading depolarization and beyond

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Neural Regeneration Research 2025年第2期20卷 481-482页

作者： Khaled Alok Timothy g.White Chunyan Li Department of Neurosurgery Donald and Barbara Zucker School of Medicine at Hofstra/NorthwellHempsteadNYUSA Translational Brain Research Laboratory The Feinstein Institutes for Medical ResearchManhassetNYUSA

Bioelectronic interventions,specifically trigeminal nerve st imulat ion(TNS),have attracted considerable attention in conditions where cortical spreading depolarizations(CSDs)accompanied by compromised cerebral perfusion may exacerbate neurological *** pharmacological interventions have demonstrated initial potential in addressing CSDs,a standardized treatment approach has not yet been *** objective of this perspective is to explore emerging bioelectronic methodologies for addressing CSDs,particularly emphasizing TNS,and to underscore TNS’s capacity to enhance neurovascular coupling and cerebral perfusion.

关键词： cerebral perfusion electronic

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Elastic Modulus,Hardness,and Fracture Toughness of Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12) Solid Electrolyte

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Chinese Physics Letters 2021年第9期38卷 108-116页

作者： Shan Hu Pengyu Xu Luize Scalco de Vasconcelos Lia stanciu Hongwei Ni Kejie Zhao State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081China School of Mechanical Engineering Purdue UniversityWest LafayetteIndiana 47907USA School of Materials Engineering Purdue UniversityWest LafayetteIndiana 47907USA

Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO) is a promising inorganic solid electrolyte due to its high Li+conductivity and electrochemical stability for all-solid-state *** characterization of LLZTO is limited by the synthesis of the condensed *** we systematically measure the elastic modules,hardness,and fracture toughness of LLZTO poly crystalline pellets of different densities using the customized environmental *** LLZTO samples are sintered using the hot-pressing method with different amounts of Li2CO3 additives,resulting in the relative density of the pellets varying from 83% to 98% and the largest grain size of 13.21 ± 5.22 μ*** mechanical properties show a monotonic increase as the sintered sample densifies,elastic modulus and hardness reach 158.47± 10.10 gPa and 11.27± 1.38 gPa,respectively,for LLZTO of 98% ***,fracture toughness increases from 0.44 to 1.51 MPa·m^(1/2),showing a transition from the intergranular to transgranular fracture behavior as the pellet density *** ionic conductivity reaches 4.54 × 10^(-4 )S/cm in the condensed LLZTO which enables a stable Li plating/stripping in a symmetric solid-state cell for over 100 *** study puts forward a quantitative study of the mechanical behavior of LLZTO of different microstructures that is relevant to the mechanical stability and electrochemical performance of all-solid-state batteries.

关键词： toughness Elastic Solid

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Impact of Zika virus non-structural protein mutations on hippocampal damage

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Neural Regeneration Research 2025年第8期20卷 2307-2308页

作者： Larissa M.g.Cassiano Roney S.Coimbra Neurogenômica/Imunopatologia Instituto RenéRachouFiocruzBelo HorizonteBrazil Departamento de Bioquímica e Imunologia Instituto de Ciências BiológicasUniversidade Federal de Minas GeraisBelo HorizonteBrazil

The Zika virus(ZIKV),a member of the Flaviviridae family,attracted worldwide attention for its connection to severe neurological effects,notably microcephaly in newborns,first reported during the 2015 epidemic in ***,its impact goes beyond fetal and neonatal abnormalities,also affecting the central nervous system(CNS)in both children and adults,leading to enduring cognitive and behavioral impairments.

关键词： damage fetal neonatal

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