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Asymmetry ratio as a parameter of Eu^3＋ local environment in phosphors

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Journal of Rare Earths 2018年第5期36卷 474-481页

作者： Ilya E. Kolesnikov Alexey v. Povolotskiy Daria v. Mamonova Evgeny Yu. Kolesnikov Alexey v. Kurochkin Erkki Lahderanta Mikhail D. Mikhailov Saint Petersburg State University 7/9 Universitetskaya nab. 199034 St.petersburg.Russia Lappeenranta University of Technology LUT Skinnarilankatu 34 53850 Lappeenranta Finland Scientific and Technological Institute of Optical Material Science VNTs S. I. Vavilov State Optical Institute Babushkina 36-1 192171 St. Petersburg Russia volga State University of Technology Lenin Sq. 3 424000 Yoshkar-Ola Russia

Study of the local environment of certain ion is quite a complex problem. Due to the unique luminescent properties, Eu^3＋ ions can be used as a structural probe. In this paper, effect of doping concentration,excitation wavelength and excitation mechanism on asymmetry ratio was systematically studied using Y3Al5O12：Eu^3＋, YvO4：Eu^3＋ and Y2O3：Eu^3＋nanophosphors. The asymmetry ratio gives information about the local surrounding and environmental changes around the Eu^3＋ ions. Asymmetry ratios of YAG：Eu^3＋and YvO4：Eu^3＋ nanopowders were calculated using standard technique and the obtained average values were found to be 0.75 and 8.2, respectively. However, it is found that standard method of asymmetry ratio calculation is suitable only for samples where all Eu^3＋ ions occupy one site. The ＂multisite model＂ of asymmetry ratio calculation was developed and used for Y2O3：Eu^3＋ nanocrystalline powders. Average value of asymmetry ratio for Eu^3＋ ions occupied ＂normal＂ sites is 6.0 and for Eu^3＋ ions occupied ＂defect＂sites is 2.3.

关键词： Eu3+ Oxide powders Luminescence Asymmetry ratio Structural probe Rare earths

HIGH SPEED CLOCKING METHODOLOGY FOR ASIC DESIGN IN FAULT TOLERANT SYSTEMS

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HIGH SPEED CLOCKING METHODOLOGY FOR ASIC DESIGN IN FAULT TOL...

Synthesis, Morphology and Magnetic Characterization of Zn Ferrite Powders

1st International Conference on ASIC

作者： Petre popescu Cristopher Kurowski Graham Thomsen Walter Jager Telecom Microelectronics Center Northern Telecom Ltd. 185 Corkstown Road Nepean Ontario K2H 2V4 Canada Telecom Microelectronics Center Northern Telecom Ltd. 185 Corkstown Road Nepean Ontario K2H 2V4 Canada Telecom Microelectronics Center Northern Telecom Ltd. 185 Corkstown Road Nepean Ontario K2H 2V4 Canada Telecom Microelectronics Center Northern Telecom Ltd. 185 Corkstown Road Nepean Ontario K2H 2V4 Canada

＜正＞ A high speed clocking methodology for ASIC design in fault tolerant systems was defined and implemented using Northern Telecom’s advanced 0.8 micron BiCMOS process. The clocking methodology supports single frequencymultiphase functional operation and provides the infrastructure for a comprehensive self test capability at ASIC level.

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Journal of Electromagnetic Analysis and Applications 2010年第10期2卷 598-600页

作者： S. A. popescu P. vlazan P. v. Notingher S. Novaconi I. Grozescu A. Bucur P. Sfirloaga National Institute for Research and Development in Electrochemistry and Condensed Matter Timisoara Romania Politehnica University of Bucharest Electrical Engineering Faculty Bucharest Romania

We synthesized Zn0.8Fe2.2O4 ferrite powders by coprecipitation and hydrothermal techniques and analyzed the mor-phology and magnetic properties. The morphology and structure of the Zn ferrite powders were investigated using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) identifying the crystallization planes. Magnetic hysteresis curves were obtained for the Zn ferrites samples.

关键词： Zn Ferrites Hysteresis Morphology and Structure

Synaptic receptors for low pH in extracellular space:metabotropic receptors are an underestimated factor in stroke

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Neural Regeneration Research 2020年第11期15卷 2033-2034页

作者： Sergei v.Fedorovich Tatsiana G.Dubouskaya Tatsiana v.Waseem Institute of Biophysics and Cell Engineering MinskBelarus Department of Biochemistry Belarusian State UniversityMinskBelarus Department of Pharmacology University of OxfordOxfordUK(Waseem TV)

In the brain,extracellular pH could decrease in certain ***,however,is especially attributable for *** accumulation in the absence of anaerobic respiration is the main,but not the only,reason for lowering pH in this condition(Wemmie et al.,2013).In addition,local pH changes in the synaptic cleft may result from the release of acidic content of synaptic vesicles(Sinning and Hubner,2013).Acidification is able to damage or even kill a *** damaging effect of low pH can be mediated by a direct effect of protons on enzymes or transport *** can also,however,be mediated by specific receptors(Wemmie et al.,2013;Levin and Buck,2015).The most well studied class of pH receptors is ionotropic acid-sensing ion channels(ASIC).These are ion channels which are permeable for sodium and *** open in response to extracellular *** of these receptors could lead to neuronal death(Wemmie et al.,2013).ASIC-induced neuronal death is appeared to be involved in stroke-induced brain *** suggestion is supported by the fact that amiloride,which inhibits ASIC,has a neuroprotective effect in stroke(Xiong et al.,2004).

关键词： al. protective damage

vanadium-doped TiO_(2)-B/anatase mesoporous nanotubes with improved rate and cycle performance for rechargeable lithium and sodium batteries

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Journal of Materials Science & Technology 2020年第19期54卷 181-189页

作者： D.P.Opra S.v.Gnedenkov A.A.Sokolov A.B.Podgorbunsky A.Yu.Ustinov v.Yu.Mayorov v.G.Kuryavyi S.L.Sinebryukhova Institute of Chemistry FEB RAS 159Pr.100-letiya Vladivostok1Vladivostok 690022Russia Far Eastern Federal University 8St.Sukhanov1Vladivostok 690950Russia

TiO_(2)-B/anatase nanotubes doped by vanadium have been synthesized through a facile one-step hydrothermal *** material shows a mesoporous structure with a specific surface area of 179.1 m^(2)g^(-1).XPS data presume the presence of v^(3+),v^(4+),v^(5+),and Ti^(3+) in doped TiO2-B/*** found by XRD and EIS investigations,the vanadium expands bronze titania crystal structure and enhances the conductivity of material by three orders of *** tested for lithium storage,the v-modified titania nanotubes show a specific capacity of 133 mA h g^(-1) after 100 charge/discharge cycles at the current density of 3000 mA g^(-1) with a Coulombic efficiency of around 98.9%,resulting in its good *** material still possesses a reversible capacity of 114 mA h g^(-1) at a very high current load of 6000 mA g^(-1),demonstrating superior rate characteristics for secondary lithium ***,v-doped Ti O2-B/anatase mesoporous nanotubes show promise performance as anode material for sodium-ion batteries,delivering about 119 mA h g^(-1) and 101 m A h g^(-1) at the current loads of 10 and 1500 m A g^(-1),respectively.

关键词： Lithium-ion battery Sodium-ion battery Anode TiO_(2)-B Anatase Doping Nanotubes Mesoporosity

Nanoscopic imaging of oxidized graphene monolayer using tip-enhanced Raman scattering.

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Nano Research 2018年第12期11卷 6346-6359页

作者： Joseph M.Smolsky Alexey v.Krasnoslobodtsev Department of Physics University of Nebraska at Omaha6001Dodge StreetOmaha NE 68182USA

Tip-enhanced Raman scattering (TERS) can be used for the structural and chemical characterization of materials with a nanoscale resolution, and offers numerous advantages compared to other forms of imaging. We use TERS to track the local structural features of a CvD-grown graphene monolayer. Ag nanoparticles were added to AFM probes using ion-beam sputtering in order to make them TERS-active. Such modification provides probes with large factors of enhancement and good reproducibility. TERS measurements on graphene show an emergence of a defect-induced D-Raman band and a strain-induced shoulder of the graphene’s G-band. Comparison of TERS results with micro-Raman for oxidized graphene suggests that local oxidation occurs with the introduction of sp3 defects, under TERS conditions.

关键词： graphene Raman spectroscopy tip-enhanced Raman scattering graphene oxidation

Bromide ion mediated modification to digestive ripening process： Preparation of ultra-small Pd, Pt, Rh and Ru nanoparticles

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Nano Research 2016年第7期9卷 2007-2017页

作者： Jhumur Seth Bhagavatula L. v. Prasad Physical and Material Chemis try Division National Chemical Laboratory (CSIR-NCL) Dr. Homi Bhabha Road Pune 411008 India

Nanoparticles of catalytically important transition metals, such as Pd, Pt, Rh, and Ru have been prepared by the well-known ＂digestive ripening＂（DR） and ＂modified digestive ripening＂（mDR） methods. In the traditional DR process, a polydisperse colloidal dispersion is refluxed in the presence of a surface-active molecule, such as alkanethiol. The mDR method involved a small modification in the procedure, wherein refluxing was performed with an alkanethiol and a tetra-alkylammonium bromide surfactant. This minor modification led to a dramatic change in the final particle size distributions, giving access to nano- particles in the 〈3 nm size regime; this was not possible with the traditional DR process. Bromide ions, which are present during refluxing, proved to be an important ingredient in the modification process. These bromide ions are revealed to act as etchants, resulting in ultra-small nanoparticles. All transition metal nanoparticles investigated displayed catalytic activity in the reduction reaction of p-nitro phenol. Pd nanoparticles, synthesized by a modified digestive ripening method, exhibited the best catalytic activity among the systems investigated.

关键词： digestive ripening ultra-small nanoparticles halide ions catalysis

Substituted diamides of dipicolinic acid as extractants and ionophores for rare earth metals

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Journal of Rare Earths 2023年第8期41卷 1234-1241,I0005页

作者： Yingchao Ren valery A.Polukeev Ekaterina v.Kenf Liudmila I.Tkachenko Mikhail Yu Alyapyshev vasily A.Babain Andrey v.Nechaev Andrey v.Legin Dmitry O.Kirsanov Institute of Chemistry Saint-Petersburg UniversityPeterhofUniversitetsky Prospect 26198504Saint-PetersburgRussia JSvC vekton Ul.2-oy Luch 9192019Saint-PetersburgRussia Khlopin Radium Institute 194021282nd Murinsky avRussia ThreeArc Mining LLC Pr.Narodnogo Opolchenia 10198216Saint-PetersburgRussia Rusredmet Vosstanovleniya str.15bl.3198320St.PeterburgKrasnoe seloRussia

The variety of newly synthesized diamides of dipicolinic acid(DPA)bearing methyl-and oxymethyl substituents in various positions of phenyl ring was investigated as potential ligands for liquid-liquid extraction of rare earth metal ions and as membrane active compounds in plasticized polymeric membranes of potentiometric *** is found that scandium is extracted with 2,6-pyridinedicarboxylic acid diamides similarly to heavy lanthanides,while yttrium is extracted together with light group *** shows high selectivity for the separation of cadmium/zinc,lead/nickel or copper/nickel *** four out of six studied ligands demonstrate significant potentiometric sensitivity towards scandium,yttrium and lanthanides in 10^(-7)-10^(-3)mol/L concentration range in nitric acid *** trends in sensitivity values vary depending on a ligand structure and the highest values are observed for Sc^(3+)and heavy *** to the evaluated selectivity Sm^(3+)is the most preferred ion,while La^(3+)is the most *** differences in sensor behavior in rare earth metal solutions assume that such devices can be applied in sensor arrays for potentiometric analysis of lanthanide mixtures.

关键词： Dipicolini cacid diamides Scandium Yttrium Lanthanides Extraction Potentiometric sensors

Influence of the low-frequency source parameters on the plasma characteristics in a dual frequency capacitively coupled plasma reactor:Two dimensional simulations

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Progress in Natural Science:Materials International 2009年第6期19卷 677-684页

作者： Xiang Xu, Hao Ge, Shuai Wang, Zhongling Dai, Younian Wang , Aimin Zhu State Key Lab of Materials Modification by Electron, ion and Laser Beams, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023, China State Key Lab of Materials Modification by Electron Ion and Laser Beams School of Physics and Optoelectronic Technology Dalian University of Technology Dalian 116023 China

A two-dimensional (2D) fluid model is presented to study the discharge of argon in a dual frequency capacitively coupled plasma (CCP) reactor. We are interested in the influence of low-frequency (LF) source parameters such as applied voltage amplitudes and low frequencies on the plasma characteristics. In this paper, the high frequency is set to 60 MHz with voltage 50 v. The simulations were carried out for low frequencies of 1, 2 and 6 MHz with LF voltage 100 v, and for LF voltages of 60, 90 and 120 v with low frequency 2 MHz. The results of 2D distributions of electric field and ion density, the ion flux impinging on the substrate and the ion energy on the powered electrode are shown. As the low frequency increases, two sources become from uncoupling to coupling. When two sources are uncoupling, the increase in LF has little impact on the plasma characteristics, but when two sources are coupling, the increase in LF decreases the uniformities of ion density and ion flux noticeably. It is also found that with the increase in LF voltage, the uniformities in the radial direction of ion density distribution and ion flux at the powered electrode decreases significantly, and the energy of ions bombarding on the powered electrode increases significantly.

关键词： Dual frequency Capacitively coupled plasma Fluid simulation