Basis for developing samarium AMS for fuel cycle analysis

International Nuclear Information System (INIS)

Buchholz, Bruce A.; Biegalski, Steven R.; Whitney, Scott M.; Tumey, Scott J.; Jordan Weaver, C.

2010-01-01

Modeling of nuclear reactor fuel burnup indicates that the production of samarium isotopes can vary significantly with reactor type and fuel cycle. The isotopic concentrations of 146 Sm, 149 Sm, and 151 Sm are potential signatures of fuel reprocessing, if analytical techniques can overcome the inherent challenges of lanthanide chemistry, isobaric interferences, and mass/charge interferences. We review the current limitations in measurement of the target samarium isotopes and describe potential approaches for developing Sm-AMS. AMS sample form and preparation chemistry will be discussed as well as possible spectrometer operating conditions.

4f and 5d magnetism in samarium

International Nuclear Information System (INIS)

Stunault, A.; Bernhoeft, N.; Vettier, C.; Dumesnil, K.; Dufour, C.

2001-01-01

We report on resonant magnetic X-ray scattering studies of a samarium epitaxial film at the samarium L 3 edge. We observe one quadrupolar resonance below the edge, reflecting the polarization of the 4f electrons, and two dipolar resonances above the edge, related to the polarization of the 5d band. We demonstrate, by following the thermal evolution of resonant magnetic intensities of both types, that the polarization of the 4f and 5d electrons present exactly the same temperature dependence, even very close to the ordering temperature, in agreement with the RKKY model for long-range magnetic order in rare earths

Studies on ultrasonic velocity and electrical conductivity of samarium soaps in non-aqueous medium

International Nuclear Information System (INIS)

Mehrotra, K.N.; Chauhan, M.; Shukla, R.K.

1990-01-01

The ultrasonic velocity of solutions of samarium soaps in non-aqueous medium has been measured at a constant temperature and the results have been used to evaluate the various acoustic parameters. The pre-micellar association and the formation of micelles in samarium soap solutions have been determined by conductometric measurements. The molar conductance at infinite dilution, degree of ionisation and ionisation constant have been evaluated. The results show that samarium soaps behave as weak electrolyte in dilute solutions. (Authors)

Diffusion of samarium into cobalt in the reduction-diffusion process

International Nuclear Information System (INIS)

Freitas Nogueira, P. de; Neto, F.B.; Landgraf, F.J.G.

1998-01-01

The presence of metallic cobalt in samarium-cobalt powders is a major cause for low magnetic properties in magnets. This paper intends to investigate the effect of time and temperature in the microstructure of powders produced by reduction-diffusion. This process, developed for the production of rare earth-transition metal alloys, consists on the reduction of the rare earth oxide with metallic calcium (or calcium hydride) and its subsequent diffusion into the cobalt particle. In the present work, a mixture of samarium oxide, cobalt powder and metallic calcium was heated to 1100 or 1200 C for 2 or 4 hours in a tubular furnace under one atmosphere of purified argon. The material thereof obtained, a sintered mass is disintegrated by aqueous crepitation. The powder was evaluated in terms of its chemical composition, its samarium yield and the intermetallic compounds present. The samarium, oxygen and calcium content of the powders produced were adequate for magnet production. However, despite the massive formation of the SmCo 5 compound after 2 hours at 1100 C, final homogeneity is attained only after 4 hours at 1200 C, with the presence of SmCo 5 and Sm 2 Co 7 and the absence of the Sm 5 Co 19 compound. Also, metallic cobalt and Sm 2 Co 17 were observed in the materials produced after 2 hours at 1100 or 1200 C. (orig.)

Nonlinear Faraday rotation in samarium vapor

International Nuclear Information System (INIS)

Barkov, L.M.; Melik-Pashaev, D.A.; Zolotorev, M.S.

1988-01-01

Experiments on nonlinear magnetic optical (Faraday) rotation on resonance transitions of atomic samarium are described. Measurements were carried out on transitions with different angular momenta of upper and lower states: 1→0, 0→1 and 1→1. Qualitative explanations of observed phenomena are given

Plasma sprayed samarium--cobalt permanent magnets

International Nuclear Information System (INIS)

Willson, M.C.; Janowiecki, R.J.

1975-01-01

Samarium--Co permanent magnets were fabricated by arc plasma spraying. This process involves the injection of relatively coarse powder particles into a high temperature gas for melting and spraying onto a substrate. The technique is being investigated as an economical method for fabricating Co--rare earth magnets for advanced traveling wave tubes and cross-field amplifiers. Plasma spraying permits deposition of material at high rates over large areas with optional direct bonding to the substrate, and offers the ability to fabricate magnets in a variety of shapes and sizes. Isotropic magnets were produced with high coercivity and good reproducibility in magnetic properties. Post-spray thermal treatments were used to enhance the magnetic properties of sprayed deposits. Samarium--Co magnets, sprayed from Sm-rich powder and subjected to post-spray heat treatment, displayed energy products in excess of 9 million G-Oe and coercive forces of approximately 6000 Oe. Bar magnet arrays were constructed by depositing magnets on ceramic substrates

Magnetoresistance of samarium in the 4.2-300 K range

International Nuclear Information System (INIS)

Trubitsyn, V.A.; Shalashov, V.F.

1980-01-01

Electric conductivity, transverse and longitudinal magnetoresistance of polycrystalline samarium with the purity of 99.9% in the 4.2-300 K temperature range and in magnetic fields up to 50 ke, are measured. The constituent of specific electric conductivity caused by spin disorder is 30.7 μOhmxcm, m*/m=2.6, the exchange parameter is G=3.1 eVxA 3 . Both transverse and longitudinal magnetoresistance are positive at 4.2 K; and the increase of temperature reveals a number of anomalies, evidently conditioned by the alteration of samarium magnetic structure

Conductometric investigations on samarium soaps

International Nuclear Information System (INIS)

Mehrotra, K.N.; Chauhan, Mithlesh; Shukla, R.K.

1989-01-01

The critical micelle concentration (CMC), degree of dissociation and dissociation constant of samarium soaps (valerate, caproate, caprylate and caprate) in a mixture of 60 per cent benzene and 40 per cent methanol were determined by using conductometric measurements. The soaps behaved as simple electrolyte in dilute solutions and the CMC was found to decrease with increasing chainlength of the fatty acid constituent of the soap. (author). 7 refs., 2 tabs

Optical isotope shifts for unstable samarium isotopes

International Nuclear Information System (INIS)

Eastham, D.A.; Walker, P.M.; Griffith, J.A.R.; Evans, D.E.; Grant, I.S.; England, J.G.; Fawcett, M.J.

1984-01-01

Using a tunable dye laser beam intersecting a thermal atomic beam, optical isotope shifts and hyperfine splittings have been measured for the four unstable samarium isotopes between 144 Sm and 154 Sm, covering the well known transition region from spherical to deformed shapes. (orig.)

The samarium Grignard reaction. In situ formation and reactions of primary and secondary alkylsamarium(III) reagents

Energy Technology Data Exchange (ETDEWEB)

Curran, D.P.; Totleben, M.J. [Univ. of Pittsburgh, PA (United States)

1992-07-15

This work shows that primary and secondary radicals are rapidly reduced in THF/HMPA to form primary- and secondary-alkylsamarium reagents. The primary- and secondary-radicals can be formed either by direct SmI{sup 2} reductions of primary- and secondary-halides or by a previous rapid radical cyclization. The samarium reagents have moderate stability in solution, and they react with a variety of typical electrophiles, including aldehydes and ketones. The work further shows that organosamarium intermediates can be involved in the traditional samarium Barbier reaction of aldehydes and ketones conducted in THF/HMPA. A new procedure called the {open_quotes}samarium Grignard{close_quotes} method is introduced, and it is suggested that this new procedure will have considerably more scope and generality than the samarium Barbier reaction. 37 refs., 4 tabs.

Fluorimetric determination of samarium(III) and europium(III) in neodymium oxide by separation with a resin column

Energy Technology Data Exchange (ETDEWEB)

Shaorong Liu; Jian Meng (Beijing Research Institute of Chemical Engineering and Metallurgy (China)); Wenhua Liu (General Research Institute for Non-Ferrous Metals (China))

1992-08-24

When thenoyltrifluoroacetone-phenanthroline-Triton X-100 is used to determine samarium(III) and europium(III) fluorimetrically, only a limited amount of neodymium(III) can be tolerated. By using an on- line separation which can partially separate neodymium(III) from samarium(III), a practical and convenient method was developed to detect samarium(III) at concentrations >0.05% and europium(III) at concentrations >0.005% in neodymium oxide. (author). 7 refs.; 4 figs.; 3 tabs.

Fluorimetric determination of samarium(III) and europium(III) in neodymium oxide by separation with a resin column

International Nuclear Information System (INIS)

Shaorong Liu; Jian Meng; Wenhua Liu

1992-01-01

When thenoyltrifluoroacetone-phenanthroline-Triton X-100 is used to determine samarium(III) and europium(III) fluorimetrically, only a limited amount of neodymium(III) can be tolerated. By using an on- line separation which can partially separate neodymium(III) from samarium(III), a practical and convenient method was developed to detect samarium(III) at concentrations >0.05% and europium(III) at concentrations >0.005% in neodymium oxide. (author). 7 refs.; 4 figs.; 3 tabs

ppt level detection of samarium(III) with a coated graphite sensor based on an antibiotic.

Science.gov (United States)

Ganjali, Mohammad Reza; Rezapour, Morteza; Pourjavid, Mohammad Reza; Haghgoo, Soheila

2004-07-01

N-[2-[4-[[[(Cyclohexylamino)carbonyl]amino]sulfonyl]phenyl]ethyl]-5-methyl pyrazine carboxamide (glipizid) was explored as an electro-active material for preparing a polymeric membrane-based sensor selective to samarium ions. The membrane incorporated 30% poly(vinyl chloride) (PVC), 53% benzyl acetate (BA), 11% glipizid and 6% sodium tetraphenyl borate. When coated on the surface of a graphite electrode, it exhibits Nernstian responses in the concentration range of 1.0 x 10(-5) to 1.0 x 10(-10) M, with a detection limit of 8.0 x 10(-11)M samarium. The electrode shows high selectivity towards samarium over several cations (alkali, alkaline earth, transition and heavy metal ions), and specially lanthanide ions. The proposed sensor has a very short response time (pH range for at least ten weeks. It was used as an indicator electrode in potentiometric titration of Sm(III) ions with an EDTA solution, and for determination of samarium in binary and ternary mixtures.

Adsorption and the initial stages of samarium condensation on iridium coated by graphite monolayer

International Nuclear Information System (INIS)

Abdullaev, R.M.; Tontegode, A.Ya.; Yusifov, F.K.

1978-01-01

Adsorption and the initial stages of vacuum samarium condensation on iridium coated by graphite monolayer (valent-saturated neutral substrate) were studied by the thermodesorption mass-spectrometry and thermoemission methods, and were compared with samarium adsorption and condensation on iridium. Desorption heat of samarium atoms with thin coating of Ir-C, equal to E approximately 1.9 eV has been determined. For desorption with Ir E is approximately 6 eV. Such a great difference in desorption heats is connected with the reduction of covalent constituent of adsorption bond in a neutral substrate. Samarium on Ir-C is found to be condensated in two states: loosely bound and tightly bound which sharply differ in properties. The tightly bound state is characterized by abnormally low vapour pressure. Possible nature of this state is discussed. Double effect on the condensation of the substrate valent saturation is noted. On the one hand, the reduction of the particle bond with the substrate decreases their concentration on the surface, preventing condensation. On the other hand, the release of the valent eloctrons of adatous brings about strong lateral interaction between them, which in its turn, promotes condensation during eased migration on the neutral substrate

Solar nebula heterogeneity in p-process samarium and neodymium isotopes.

Science.gov (United States)

Andreasen, Rasmus; Sharma, Mukul

2006-11-03

Bulk carbonaceous chondrites display a deficit of approximately 100 parts per million (ppm) in 144Sm with respect to other meteorites and terrestrial standards, leading to a decrease in their 142Nd/144Nd ratios by approximately 11 ppm. The data require that samarium and neodymium isotopes produced by the p process associated with photodisintegration reactions in supernovae were heterogeneously distributed in the solar nebula. Other samarium and neodymium isotopes produced by rapid neutron capture (r process) in supernovae and by slow neutron capture (s process) in red giants were homogeneously distributed. The supernovae sources supplying the p- and r-process nuclides to the solar nebula were thus disconnected or only weakly connected.

Crystallization of Yttrium and Samarium Aluminosilicate Glasses

OpenAIRE

Lago, Diana Carolina; Prado, Miguel Oscar

2016-01-01

Aluminosilicate glasses containing samarium and yttrium (SmAS and YAS glasses) exhibit high glass transition temperatures, corrosion resistance, and glass stability on heating which make them useful for technological applications. Yttrium aluminosilicate glass microspheres are currently being used for internal selective radiotherapy of liver cancer. During the preparation process, crystallization needs to be totally or partially avoided depending on the final application. Thus knowing the cry...

Determination of 0.01–0.1% of samarium in 40–100 mg of lead chloride

NARCIS (Netherlands)

Agterdenbos, J.; Jütte, B.A.H.G.; Schuring, J.

1971-01-01

A method is described for the determination of 5–25 μg of samarium in about 40 mg of lead chloride, based on the removal of the lead by electrolysis and determination of the samarium by extraction with PAN and measurement of the extinction of the complex at 552 nm.

Synthesis and structure of unprecedented samarium complex with bulky bis-iminopyrrolyl ligand via intramolecular C=N bond activation

Energy Technology Data Exchange (ETDEWEB)

Das, Suman; Anga, Srinivas; Harinath, Adimulam; Panda, Tarun K. [Department of Chemistry, Indian Institute of Technology, Hyderabad (India); Pada Nayek, Hari [Department of Applied Chemistry, Indian Institute of Technology, (ISM) Dhanbad, Jharkhand (India)

2017-12-29

An unprecedentate samarium complex of the molecular composition [{κ"3-{(Ph_2CH)N=CH}{sub 2}C{sub 4}H{sub 2}N}{κ"3-{(Ph_2CHN=CH)(Ph_2CHNCH)C_4H_2N}Sm}{sub 2}] (2), which was isolated by the reaction of a potassium salt of 2,5-bis{N-(diphenylmethyl)-iminomethyl}pyrrolyl ligand [K(THF){sub 2}{(Ph_2CH)N=CH}{sub 2}C{sub 4}H{sub 2}N] (1) with anhydrous samarium diiodide in THF at 60 C through the in situ reduction of imine bond is presented. The homoleptic samarium complex [[κ{sup 3}-{(Ph_2CH)-N=CH}{sub 2}C{sub 4}H{sub 2}N]{sub 3}Sm] (3) can also be obtained from the reaction of compound 1 with anhydrous samarium triiodide (SmI{sub 3}) in THF at 60 C. The molecular structures of complexes 2 and 3 were established by single-crystal X-ray diffraction analysis. The molecular structure of complex 2 reveals the formation of a C-C bond in the 2,5-bis{N-(diphenylmethyl)iminomethyl}pyrrole ligand moiety (Ph{sub 2}Py{sup -}). However, complex 3 is a homoleptic samarium complex of three bis-iminopyrrolyl ligands. In complex 2, the samarium ion adopts an octahedral arrangement, whereas in complex 3, a distorted three face-centered trigonal prismatic mode of nine coordination is observed around the metal ion. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Effect of samarium in corrosion and microstructure of Al-5Zn-0.5Cu as low driving voltage sacrificial anode

Science.gov (United States)

Pratesa, Yudha; Ferdian, Deni; Ramadhan, Fajar Yusya; Maulana, Bramuda

2018-05-01

Sacrificial Anode Low voltage is the latest generation of the sacrificial anode that can prevent the occurrence of Hydrogen Cracking (HIC) due to overprotection. The Al-5n-0.5Cu alloy showed the potential to be developed as the new sacrificial anode. However, the main problem is copper made Al2Cu intermetallic in grain boundary. Samarium is added to modify the shape of the intermetallic to make it finer and make the corrosion uniform. Several characterizations were conducted to analyze the effect of Samarium. Scanning electron microscope (SEM) and Energy dispersive spectroscopy was used to analyzed the microstructure of the alloy. Metallography preparation was prepared for SEM analysis. Corrosion behavior was characterized by cyclic polarization in 3.5% NaCl solution. The results show samarium can change the shape of intermetallic and refine the grains. In addition, samarium makes better pitting resistance and exhibits a tendency for uniform corrosion. It is indicated by the loop reduction (ΔEpit-prot). Current density increased as an effect of samarium addition from 6x10-5 Ampere (Al-5Zn-0.5Cu) to 2.5x10-4 Ampere (Al-5Zn-0.5Cu-0.5Sm). Steel potential protection increased after addition of samarium which is an indication the possibility of Al-Zn-Cu-Sm to be used as low voltage sacrificial anode.

Ultrasonic and viscosimetric studies of samarium laurate in benzene-dimethylsulfoxide mixtures

International Nuclear Information System (INIS)

Mehrotra, K.N.; Anis, M.

1995-01-01

Ultrasonic and viscosity measurements of samarium laurate in benzene-DMSO mixtures of different compositions (7:3 and 1:1 V/V) have been used to determine the critical micelle concentration (CMC), soap-solvent interaction, and various acoustic parameters of the system. The values of critical micelle concentration increase with increasing amount of DMSO in the solvent mixtures. The viscosity results have been explained on the basis of equations proposed by Einstein, Vand. Moulik, and Jones-Dole. The values of CMC for samarium laurate obtained from the viscosity measurements are in agreement with the results obtained from ultrasonic measurements. The results show that the soap molecules do not aggregate appreciably below CMC there is a marked change in the aggregation behaviour at CMC. (author)

Behavior of Samarium III during the sorption process; Comportamiento del Samario-III durante el proceso de sorcion

Energy Technology Data Exchange (ETDEWEB)

Ordonez R, E.; Garcia G, N.; Garcia R, G. [ININ, Carr. Mexico-Toluca Km 36.5, Salazar, Estado de Mexico (Mexico)]. e-mail: edo@nuclear.inin.mx

2004-07-01

In this work the results of the behavior of samarium in solution are presented, in front of a fine powder of zirconium silicate (zircon). For that which is necessary to characterize the zircon, studying the crystallinity, the morphology, the surface area and the isoelectric point. The behavior of samarium in solution is studied by means of the elaboration of isotherm of sorption, using the technique by lots. One observes that to pH values of nearer to the isoelectric point (pH = 7.23) the process of sorption of the samarium begins, reaching a maximum to near pH at 9. The technique of luminescence is used to determine the concentration of the sipped samarium (phosphorescence) and also to make the speciation of the species formed in the surface of the zircon (phosphorescence). The results can be extrapolated with the plutonium when making the modeling of the migration of alpha emitting coming from the repositories of radioactive waste since both they have similar chemical properties (they are homologous). (Author)

Inductively coupled plasma optical emission spectrometry analysis of lanthanum, samarium and gadolinium oxides for rare earths impurities

International Nuclear Information System (INIS)

Reino, L.C.P.; Lordello, A.R.

1990-09-01

An inductively coupled plasma optical emission spectrometry method is described for the determination of Sm, Eu, La, Gd, Dy, Pr, Ho, Nd, Tb and Y in purified oxides of lanthanum, samarium and gadolinium. The method enables a simple, precise and readily available determination. Dissolution of the samples is achieved with diluted hydrochloric acid (1:1). The solutions are diluted to volume for a concentration of 1mg/ml. The lowest determination limit is 0,01% for most elements and 0,05 or 0,1% for a few rare earths in samarium and gadolinium matrices. Lanthanum, Samarium and Gadolinium concentrates with purity grade of 99,9%, 99,6% and 99,8%, respectively, can be analysed by this procedure. (author)

Pemisahan Unsur Samarium dan Yttrium dari Mineral Tanah Jarang dengan Teknik Membran Cair Berpendukung (Supported Liquid Membrane

Directory of Open Access Journals (Sweden)

Amri Amin

2009-06-01

Full Text Available he increasing use of rare earth elements in high technology industries needs to be supported by developmental work for the separation of elements. The research objective is fiercely attracting and challenging considering the similarity of bath physical and chemical properties among these elements. The rate separation of samarium and yttrium elements using supported liquid membrane has been studied. Polytetrafluoroethylene (PTFE with pore size of 0.45 µm has been used as the membrane and di(2-ethylhexyl phosphate (D2EHP in hexane has been used as a carrier and nitric acid solution has been used as receiving phase. Result of experiments showed that the best separation rate of samarium and yttrium elements could be obtained at feeding phase of pH 3.0, di(2-ethylhexyl phosphate (D2EHP concentration of 0.3 M, agitation rate of 700 rpm, agitation time of 2 hours, and nitric acid and its solution concentrations of 1.0 M and 0.1 M, respectively. At this condition, separation rates of samarium and yttrium were 64.4 and 67.6%, respectively.   Keywords: liquid membrane, rare earth elements, samarium, yttrium

Preparation and examination of properties of samarium-153-EDTMP complex

International Nuclear Information System (INIS)

Nowak, M.; Garnuszek, P.; Lukasiewicz, A.; Wozniak, I.; Zulczyk, W.; Licinska, I.

1995-01-01

Preparation and properties of ethylenediaminetetramethylenephosphonic acid (EDTMP) as well as some properties of 153 Sm-EDTMP chelate have been examined. The chelate formed by samarium-153 (46.3 h, β - -decay) with EDTMP exhibits high bone uptake and can be used for treatment of disseminated, painful skeletal metastases. The purity and stability of solutions of 153 Sm-EDTMP chelate were examined in a broad range of samarium concentration and 153 Sm specific activity. The complex under study was examined by radio-TLC, -electrophoresis and radio-HPLC. The results obtained suggest the small size of molecules of 153 Sm-EDTMP chelate as compared with molecules of ''free''EDTMP. The results of biodistribution of 153 Sm-EDTMP determined in rats indicate the quick blood clearance, high deposition of radioactivity in bone and quick excretion of radioactivity into urine. No specific uptake of 153 Sm-EDTMP in extra-skeletal organs was found. (author). 42 refs, 13 figs, 22 tabs

Expedient Method for Samarium(II) Iodide Preparation Utilizing a Flow Approach

Czech Academy of Sciences Publication Activity Database

Voltrová, Svatava; Šrogl, Jiří

2013-01-01

Roč. 24, č. 3 (2013), s. 394-396 ISSN 0936-5214 R&D Projects: GA MŠk LH12013 Institutional support: RVO:61388963 Keywords : flow * samarium * iodide * reduction Subject RIV: CC - Organic Chemistry Impact factor: 2.463, year: 2013

Optical properties of zinc–vanadium glasses doped with samarium ...

Indian Academy of Sciences (India)

Abstract. Zinc–vanadium glasses doped with samarium oxide having the chemical composition Sm2O3(x). ZnO(40−x)V2O5(60)(where x = 0·1–0·5 mol%) were prepared by melt quenching method. The density of these glasses was measured by Archimedes method; the corresponding molar volumes have also been ...

X-ray spectrum in the range (6-12) A emitted by laser-produced plasma of samarium

International Nuclear Information System (INIS)

Louzon, Einat; Henis, Zohar; Levi, Izhak; Hurvitz, Gilad; Ehrlich, Yosi; Fraenkel, Moshe; Maman, Shlomo; Mandelbaum, Pinchas

2009-01-01

A detailed analysis of the x-ray spectrum emitted by laser-produced plasma of samarium (6-12 A) is presented, using ab initio calculations with the HULLAC relativistic code and isoelectronic considerations. Resonance 3d-nf (n=4 to 7), 3p-4d, 3d-4p, and 3p-4s transitions in Ni samarium ions and in neighboring ionization states (from Mn to Zn ions) were identified. The experiment results show changes in the fine details of the plasma spectrum for different laser intensities.

Synthesis of samarium binding bleomycin - a possible NCT radiosensitizer

Energy Technology Data Exchange (ETDEWEB)

Mendes, B.M., E-mail: bmm@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Mendes, T.M.; Campos, T.P.R., E-mail: campos@nuclear.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

2011-07-01

Bleomycin (BLM) is a drug that has attractive features for the development of a new radiopharmaceutical, particularly with regard to neutron capture therapy (NCT) sensitized by Sm-149. It has the ability to chelate many metal ions. In vitro studies have shown that up to 78% of BLM present in a cell is accumulated inside the nucleus or in the nuclear membrane. In addition, this drug has higher affinity for tumor tissues than for normal tissues. Radioactive isotopes carried by this antibiotic would be taken preferentially to one important cellular targets DNA. Besides, BLM displays intrinsic anti-tumor activity - it is a chemotherapic antibiotic clinically used against some cancers. This study aimed to obtain bleomycin molecules bound to samarium (BLM-Sm) for NCT studies in vitro and in vivo. The binding technique employed in this work has great simplicity and low cost. Thin layer chromatography, high performance liquid chromatography, fast protein liquid chromatography and analysis by ICP-AES were applied to verify the binding molecule. ICP-AES results showed the presence of samarium in the sample peaks related to BLM-Sm. However, efficiency and stability of this bond needs to be investigated. (author)

Synthesis of samarium binding bleomycin - a possible NCT radiosensitizer

International Nuclear Information System (INIS)

Mendes, B.M.; Mendes, T.M.; Campos, T.P.R.

2011-01-01

Bleomycin (BLM) is a drug that has attractive features for the development of a new radiopharmaceutical, particularly with regard to neutron capture therapy (NCT) sensitized by Sm-149. It has the ability to chelate many metal ions. In vitro studies have shown that up to 78% of BLM present in a cell is accumulated inside the nucleus or in the nuclear membrane. In addition, this drug has higher affinity for tumor tissues than for normal tissues. Radioactive isotopes carried by this antibiotic would be taken preferentially to one important cellular targets DNA. Besides, BLM displays intrinsic anti-tumor activity - it is a chemotherapic antibiotic clinically used against some cancers. This study aimed to obtain bleomycin molecules bound to samarium (BLM-Sm) for NCT studies in vitro and in vivo. The binding technique employed in this work has great simplicity and low cost. Thin layer chromatography, high performance liquid chromatography, fast protein liquid chromatography and analysis by ICP-AES were applied to verify the binding molecule. ICP-AES results showed the presence of samarium in the sample peaks related to BLM-Sm. However, efficiency and stability of this bond needs to be investigated. (author)

Influence of pretreatment temperature cycling on the radiating defect formation in silicon doped by samarium

International Nuclear Information System (INIS)

Abdurakhmanov, K.P.; Nazyrov, D.E.

2006-01-01

Full text: The raise of thermal and radiation stability as it is known, is one of actual problems of physics semiconductors. Recently it is established, that the rare-earth elements (REE) raise a stability of silicon to exterior action. In this connection the investigation of silicon doped REE by samarium and influence on its properties of heat treatments and radiation exposure is important. In sectional operation the outcomes of investigations of influence of samarium on thermal (600 degree C are reduced; 600 deg. + 900 deg. C; 900 deg. C; 900 deg. C + 600 deg. C; 1100 deg. C; 600 deg. C + 900 deg. C + 1100 deg. C; 900 deg. C + 600 deg. C + 1100 deg. C) thermal defect formation and radiation defect formation (exposure of γ-quanta 60 Co) both in beforehand wrought, and in thermally unfinished samples. After each cycle of heat treatments samples cool fast (throwing off in oil) or slowly (together with the furnace). Doping n-silicon REE by gadolinium and samarium was carried out during cultivation. The concentration of gadolinium and samarium in silicon, on sectional of a neutron-activation analysis was equaled 10 14 - 10 18 cm -3 . As control is model monocrystal silicon such as KEP-15/50. Para-meters of deep levels originating in control and doped REE samples, both past heat treatment or temperature cycling, and irradiated by the γ-quanta are defined by methods of a capacity spectroscopy: DLTS and IRC. The obtained outcomes have shown, that in irradiated with the γ-quanta 60 Co deep levels samples are formed with energies: E C -0,17 eV, E C -0,32 eV, EC-0,41 eV. Thus the parameters of deep levels vary depending on requirements of prestress heat treatment. For example heat treatment at 600 deg. C essentially increments a velocity of introduction of and centre (deep level of E C -0,17 eV), in comparison with a velocity of introduction of this level in samples with prestress heat treatment at 900 deg. C. In samples n-Si doped by samarium effectiveness of formation

Sorption of samarium in iron (II) and (III) phosphates in aqueous systems

International Nuclear Information System (INIS)

Diaz F, J.C.

2006-01-01

The radioactive residues that are stored in the radioactive confinements its need to stay isolated of the environment while the radioactivity levels be noxious. An important mechanism by which the radioactive residues can to reach the environment, it is the migration of these through the underground water. That it makes necessary the investigation of reactive materials that interacting with those radionuclides and that its are able to remove them from the watery resources. The synthesis and characterization of materials that can be useful in Environmental Chemistry are very important because its characteristics are exposed and its behavior in chemical phenomena as the sorption watery medium is necessary to use it in the environmental protection. In this work it was carried out the sorption study of the samarium III ion in the iron (II) and (III) phosphate; obtaining the sorption isotherms in function of pH, of the phosphate mass and of the concentration of the samarium ion using UV-visible spectroscopy to determine the removal percentage. The developed experiments show that as much the ferrous phosphate as the ferric phosphate present a great affinity by the samarium III, for what it use like reactive material in contention walls can be very viable because it sorption capacity has overcome 90% to pH values similar to those of the underground and also mentioning that the form to obtain these materials is very economic and simple. (Author)

Impact of educational strategies in positioning Samarium-153 EDTMP as a treatment for metastatic bone pain

International Nuclear Information System (INIS)

Seminario, C.; Morales, R.; Castro, M.; Cano, R.A.; Mendoza, G.

2005-01-01

To educate is a difficult task but its results make efforts worthwhile. Many patients in Peru suffer from intractable bone pain due to metastases. Since 1993 radionuclides were used to palliate bone pain due to metastases in Peru. First, with the help of the IAEA, Peru participated in a clinical trial using Phosphorus 32 and Strontium 89. Then, efforts were performed to produce Samarium 153 EDMTP locally, which was achieved in 1995. Nevertheless, years passed and Samarium use did not increase proportionally to the needs of people with cancer and bone pain, mainly the poor. Educational strategies have been proven useful for delivering solutions to many health problems in other diseases and also in cancer. Health education makes patients and their relatives assume responsible care of their problems. The purpose of this work was to increase Samarium EDTMP use as palliative treatment in patients with bone pain due to metastases, using educational strategies as means to change attitudes towards this health problem. In September 2003, a task group conducted studies in order to apply several methods to achieve the goal of increasing Samarium EDTMP use. Educational strategies employed were performed to provide verbal and written information to patients, physicians, medical students, residents, pain specialists, oncologists and neurologists, as well as general public. Verbal information included radio interviews, television spots and a phone number (in charge of two secretaries, prepared for answering and if not possible, a physician was in charge of attending patient consultation), e-mail and a web page for consultation. Written material was delivered to several newspapers, including clinical use of Samarium, possibilities of being elected for treatment, benefits and risks and a photography of the product. Politics of the institution producing Samarium changed, in order to achieve minimum cost of the product and it was delivered to all publics at the lowest cost for a year

Lanthanum (samarium) nitrate-4-aminoantipyrine nitrate-water systems

International Nuclear Information System (INIS)

Starikova, L.I.; Zhuravlev, E.F.

1985-01-01

Using the isothermal method of cross-sections at 50 deg C systems lanthanum nitrate-4-aminoantipyrine nitrate-water (1), samarium nitrate-4-aminoantipyrine nitrate-water (2), are studied. Isotherms of system 1 consist of two crystallization branches of initial salt components. In system 2 formation of congruently soluble compounds of the composition Sm(No) 3 ) 3 xC 11 H 13 ON 3 xHNO 3 is established. Analytical, X-ray phase and thermogravimetric analysis of the isolated binary salt are carried out

Collective effects in even-mass samarium isotopes by polarized-proton scattering

NARCIS (Netherlands)

Petit, R.M.A.L.; Hall, van P.J.; Klein, S.S.; Moonen, W.H.L.; Nijgh, G.J.; Overveld, van C.W.A.M.; Poppema, O.J.

1993-01-01

The even-mass samarium isotopes 148,...,152Sm have been investigated by polarized proton scattering at 20.4 MeV beam energy. The data have been analysed with an 'extended' optical model, where the intensities of the first maxima of the main inelastic channels are fitted in a coupled-channels

Synthesis of samarium, europium and ytterbium acetylenides

International Nuclear Information System (INIS)

Bochkarev, M.N.; Fedorova, E.A.; Glushkova, N.V.; Protchenko, A.V.; Druzhkov , O.N.; Khorshev, S.Ya.

1995-01-01

Ethynyl complexes of samarium, europium and ytterbium were prepared by interaction of naphthalinides of metals with acetylene in tetrahydrofuran. The compounds are isolated in the form of dark-coloured pyrophore powders. Data of magnetic measurements suggest that in the course of the reaction Sm(2) is oxidized completely to Sm(3), Yb(2) transforms into Yb(3) partially, whereas europium preserves its initial bivalent state. Hydrolysis of the compounds prepared provides acetylene, ethylene, ethane and hydrogen which indicates the presence of acethylenide Ln 2 C 2 and hydride LnH groupings (Ln = Sm, Eu, Yb). 9 refs., 2 tabs

Sorption-desorption of samarium in Febex bentonite

International Nuclear Information System (INIS)

Ramirez-Guinart, O.; Rigol, A.; Vidal, M.; Fernandez-Poyatos, P.; Alba, M. D.

2012-01-01

Document available in extended abstract form only. The chemical and physical nature of the clay is a key issue in the design of engineered barriers. The FEBEX bentonite is one of the clays candidates to be used in engineered barriers in deep geology repositories (DGR). Here, its performance was tested with respect to the sorption-desorption of samarium, which is a lanthanide that, besides being considered as a natural analogue of actinides, may also be present in high level radioactive waste in the form of the radioactive isotope 151 Sm. FEBEX bentonite was used in this study. This is a di-octahedral smectite, with isomorphic substitutions in tetrahedral and octahedral sheets. Its theoretical cation exchange capacity value is 1500 meq kg -1 . Sorption isotherms were obtained for Sm in the range of initial concentrations of 0.01 and 9 meq l -1 . Tests were carried out in deionized water and in a medium simulating the composition of interstitial water. Sorption tests were performed equilibrating 30 ml of the Sm solution with 0.2 g of clay. After a contact time of 24 hours, supernatants were decanted off after centrifugation. The quantification of the concentration of Sm in the initial and final solutions allowed us to quantify the Sm equilibrium concentration (C eq ), the fraction sorbed in the FEBEX bentonite (C sorb ) and to derive the sorption K d data. Desorption tests were applied to determine the desorption K d and the percentage of Sm reversibly sorbed. Desorption tests were performed with the bentonite residue from the sorption step, under the same experimental conditions, but without Sm. Powder X-ray diffractograms were obtained from 3 to 70 deg. 2θ with a step of 0.05 deg. and a counting time of 3 s. The crystalline phases were identified using the computer program X'Pert HighScore. The morphology of the samples was analyzed by SEM at 20 kV. An EDX system was fitted to the SEM equipment to perform chemical analyses of the samples using a Si/Li detector

Laser spectroscopy of atomic samarium

International Nuclear Information System (INIS)

Barkov, L.M.; Melik-Pashaev, D.A.; Zolotorev, M.S.

1988-01-01

Samarium spectrum was studied with a purpose to find transitions to be used in experiments on parity nonconservation. Macaluso-Corbino effect - Faraday rotation near resonance was used for the search and study of spectral lines. We have identified previously unknown energy levels belonging to the 4f 5 6s 2 5 D term: 15914.55(3) cm -4 (J=1), 17864.29(3) cm -4 (J=2), 20195.76(3) cm -4 (J=3). M1-transitions to these levels from the levels of the ground 4f 5 6s 2 7 F term were observed. There are several peculiarities of these transitions which are due to the fact that they occut within an inner 4f 5 -shell, particularly, a very small presuure broadening by inert gases. 44 refs.; 17 figs.; 7 tabs

Synthesis of samarium complexes with the derivative binder of Schiff Quinolinic base. Characterization and photophysical study

International Nuclear Information System (INIS)

Lucas H, J.

2016-01-01

In this work we determined the metal: binder stoichiometry of the species formed during the UV/Vis spectrophotometric titration of the derivative binder of Schiff quinolinic base, L1 with the samarium nitrate pentahydrate in methanol. Statistical analysis of the data allowed proposing the metal: binder stoichiometry for the synthesis of the complexes which was one mole of samarium salt by 2.5 moles of binder and thus favor the formation of complexes with 1M: 1L and 1M: 2L stoichiometries. They were synthesized in aqueous-organic medium (water-ethanol), isolated and purified two complexes with stoichiometry 1 Sm: 1 L1, complex 1 and 1 Sm: 2 L1, complex 2. The overall yield of the reaction was 76%. The characterization of the formed complexes was performed by visible ultraviolet spectrometry (UV/Vis), nuclear magnetic resonance, X-ray photoelectron spectroscopy (XP S), thermal gravimetric analysis with differential scanning calorimetry (TGA/DSC), and radial distribution function. These complexes were studied by fluorescence and emission phosphorescence at variable temperature. Spectroscopic techniques used in both solution and solid demonstrated the formation and stability of these complexes. In addition XP S indicated that in both complexes the samarium retains its oxidation state 3+. Luminescence studies indicated that there is intra-binding charge transfer which decreases the transfer of light energy from the binder to the samarium. Based on the experimental results, L1 binder molecules and complexes 1 and 2 were modeled that demonstrated the proposed Nc for each complex, as well as allowed to visualize the structural arrangement of the molecules, complexes and binder. (Author)

Removal of trivalent samarium from aqueous solutions by activated biochar derived from cactus fibres

Institute of Scientific and Technical Information of China (English)

Loukia Hadjittofi; Styliana Charalambous; Ioannis Pashalidis

2016-01-01

The efficiency of activated biochar fibres obtained fromOpuntia Ficus Indica regarding the sorption of trivalent samarium (Sm(III)) from aqueous solutions was investigated by batch experiments. The effect of various physicochemical parameters (e.g. pH, initial metal concentration, ionic strength, temperature and contact time) on the Sm(III) adsorption was studied and the surface species were characterized by FTIR spectroscopy prior to and after the lanthanide sorption. The experimental results showed that the acti-vated biochar fibres possessed extraordinary sorption capacity for Sm(III) in acidic solutions (qmax=90 g/kg, pH 3.0) and near neutral solutions (qmax=350 g/kg, pH 6.5). This was attributed to the formation of samarium complexes with the surface carboxylic moieties, available in high density on the lamellar structures of the bio-sorbent.

Pressure and irradiation effects on transport properties of samarium compounds with instable valence

International Nuclear Information System (INIS)

Morillo, J.

1981-01-01

Electron transport properties in samarium compounds with instable valence are studied in this thesis: from SmS in its integer valence phases at common pressure to SmB 6 compound IV at common pressure through SmSsub(1-x)Psub(x) (x 6 is presented [fr

Graphite furnace atomic absorption spectrometry with a tantalum boat for the determination of yttrium, samarium, and dysprosium in a mish metal

International Nuclear Information System (INIS)

Daidoji, Hidehiro; Tamura, Shohei

1982-01-01

The determination of yttrium, samarium, and dysprodium by means of graphite-furnace atomic absorption spectrometry (AAS) was studied by a tantalum boat inserted into a graphite tube atomizer. These elements could not be determined by the use of a commercial graphite tube, In the atomization from a tantalum boat, better analytical sensitivities and negligible memory effects for these rare earths are obtained. The analytical sensitivities of yttrium, samarium, and dysprodium with the tantalum boat were 0.60 ng, 0.86 ng, and 0.17 ng respectively. This method was applied for the determination of yttrium, samarium, and dysprosium in a mish metal. The measurements were performed with slightly acidified solutions (0.01 mol dm 3 HCI or HNO 3 ). The sensitivities and the precisions for these elements decreased with increasing acid concentration. An enhancement in the sensitivities of yttrium and dysprosium upon the addition of a large excess of lanthanum, neodymium, and praseodymium salts were observed. The yttrium, samarium, and dysprosium in a mish metal were determined with both analytical curves of standard solutions containing an excess of lanthanum, cerium, and neodymium ions and of the standard addition. The precisions for this work were in the 3 - 9.3% range. (author)

Polypyrrole-coated samarium oxide nanobelts: fabrication, characterization, and application in supercapacitors

Science.gov (United States)

Liu, Peng; Wang, Yunjiao; Wang, Xue; Yang, Chao; Yi, Yanfeng

2012-11-01

Polypyrrole-coated samarium oxide nanobelts were synthesized by the in situ chemical oxidative surface polymerization technique based on the self-assembly of pyrrole on the surface of the amine-functionalized Sm2O3 nanobelts. The morphologies of the polypyrrole/samarium oxide (PPy/Sm2O3) nanocomposites were characterized using transmission electron microscope. The UV-vis absorbance of these samples was also investigated, and the remarkable enhancement was clearly observed. The electrochemical behaviors of the PPy/Sm2O3 composites were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge. The results indicated that the PPy/Sm2O3 composite electrode was fully reversible and achieved a very fast Faradaic reaction. After being corrected into the weight percentage of the PPy/Sm2O3 composite at a current density of 20 mA cm-2 in a 1.0 M NaNO3 electrolyte solution, a maximum discharge capacity of 771 F g-1 was achieved in a half-cell setup configuration for the PPy/Sm2O3 composites electrode with the potential application to electrode materials for electrochemical capacitors.

Peculiarities of electronic, phonon and magnon subsystems of lanthanum and samarium tetraborides

Energy Technology Data Exchange (ETDEWEB)

Novikov, V.V., E-mail: vvnovikov@mail.ru; Mitroshenkov, N.V.; Matovnikov, A.V.

2015-10-15

Experimental research was carried out to study the temperature dependences of heat capacity C{sub p}(T = 2–300 K), lattice parameters a(T), and ≿(T), (5–300 K) of lanthanum and samarium tetraborides. A comparison with data obtained previously for LuB{sub 4} reveals the peculiar influence of lanthanide contraction and the rare-earths mass on the thermodynamic properties of rare earth tetraborides at low and high temperatures. Sharp anomalies were found in the heat capacity and thermal expansion for SmB{sub 4} at T{sub N} = 25.1 K, conditioned by the phase transition into antiferromagnetic state. The more poorly defined heat capacity anomaly around 7 K is referred to the quadrupole orbital fluctuation of the atomic magnetic moments for Sm{sup 3+} ions. The electronic, lattice, and magnetic contributions to the heat capacity and thermal expansion of samarium tetraboride were defined. Our approach makes it possible to adequately approximate the lattice components of heat capacity and thermal expansion by combining the Debye and Einstein contributions, which are based on the joint analysis of calorimetric and X-ray data. The influence of the frustration of the atomic magnetic moment system for Sm{sup 3+} ions on the thermodynamic characteristics of the samarium tetraboride magnetic phase transition was revealed. - Highlights: • The heat capacity and lattice parameters for LaB{sub 4} and SmB{sub 4} were determined at 2–300 K. • The anomalies of C{sub p}(T), a(T), c(T) for SmB{sub 4} due to the phase transition are revealed. • The lattice contributions to the thermal properties of LaB{sub 4} and SmB{sub 4} are analyzed.

Ekstraksi Pemisahan Neodimium dari Samarium, Itrium dan Praseodimium Memakai Tri Butil Fosfat

Directory of Open Access Journals (Sweden)

Maria Veronica Purwani

2017-05-01

Full Text Available The extraction of Nd(OH3 (neodymium hydroxide concentrate containing Y (yttrium, Sm (samarium and Pr (praseodymium as product of monazite processed has been done. The purpose of this study is to determine the separation of Nd from Y, Pr and Nd Sm in Nd concentrate. The aqueous phase was concentrated Nd (OH3 in HNO3 and extractant while organic phase was Tri Butyl Phosphate (TBP in kerosene. Parameters studied were pH and concentration feed, concentration of TBP in kerosene, extraction time and stirring speed. The result showed that the optimization of separation extraction neodymium from samarium, yttrium and praseodymium in Nd(OH3 concentrated with TBP, obtained the optimum condition of pH = 0.2, concentration of feed 100 g /L, concentration of TBP in kerosene 5%, extraction time 15 minutes and stirring speed 150 rpm. With the conditions, Separation Factor (SF obtained for Nd-Y, Nd-Pr, Nd-Sm are 2.242, 4.811, 4.002 respectively, while D and extraction efficiency of Nd are 0.236 and 19.07%.

Australian manufacture of QuadrametTM (Samarium-153 EDTMP)

International Nuclear Information System (INIS)

Wood, N.R.; Whitwell, J.

1997-01-01

Quadramet T (Samarium-153 EDTMP) has been shown overseas to be potentially useful in the palliation of painful osteoblastic skeletal metastases and has been approved this year for general marketing in the USA. Australian Radioisotopes (ARI) has licensed this product from the Australian patent holders, Dow Chemical. Within the facilities of ARI, a hot cell has been dedicated to this product and fitted out to manufacture it weekly on a cycle related to the operating cycle of the Australian reactor HIFAR. Due to neutron flux limitations of HIFAR, the local formulation has an elemental Samarium content up to 200μg/mL whereas the overseas formulation has a level of 20-46μg/mL. All other specifications of the two products are essentially the same. In 1995 and 1996 a small clinical trial with 19 patients was held which demonstrated that the pharmacokinetic behaviour was also essentially the same by measuring blood clearance rates and skeletal uptake dynamics. Soft tissue uptake was also qualitatively determined. The ARI version is now the subject of an application for general marketing within Australia. Some useful characteristics of this agent are: almost complete excretion or fixation in the skeleton within 6 hours, rapid onset of clinical effect, applicability in most cases where an abnormal diagnostic bone scan correlates with painful sites, dosage can be tailored to individual patient uptake due to easy dose measurement and retreatment is quite possible. The use of this class of agents in pain palliation continues to increase. Australian manufacture of Quadramet TM provides a further option in the management of these difficult cases

Polypyrrole-coated samarium oxide nanobelts: fabrication, characterization, and application in supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Liu Peng, E-mail: pliu@lzu.edu.cn; Wang Yunjiao; Wang Xue; Yang Chao; Yi Yanfeng [College of Chemistry and Chemical Engineering, Lanzhou University, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province and State Key Laboratory of Applied Organic Chemistry (China)

2012-11-15

Polypyrrole-coated samarium oxide nanobelts were synthesized by the in situ chemical oxidative surface polymerization technique based on the self-assembly of pyrrole on the surface of the amine-functionalized Sm{sub 2}O{sub 3} nanobelts. The morphologies of the polypyrrole/samarium oxide (PPy/Sm{sub 2}O{sub 3}) nanocomposites were characterized using transmission electron microscope. The UV-vis absorbance of these samples was also investigated, and the remarkable enhancement was clearly observed. The electrochemical behaviors of the PPy/Sm{sub 2}O{sub 3} composites were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge. The results indicated that the PPy/Sm{sub 2}O{sub 3} composite electrode was fully reversible and achieved a very fast Faradaic reaction. After being corrected into the weight percentage of the PPy/Sm{sub 2}O{sub 3} composite at a current density of 20 mA cm{sup -2} in a 1.0 M NaNO{sub 3} electrolyte solution, a maximum discharge capacity of 771 F g{sup -1} was achieved in a half-cell setup configuration for the PPy/Sm{sub 2}O{sub 3} composites electrode with the potential application to electrode materials for electrochemical capacitors.

Production of SmCo5 alloy by calciothermic reduction of samarium oxide

International Nuclear Information System (INIS)

Krishnan, T.S.; Gupta, C.K.

1988-01-01

Among the established permanent magnets, SmCo 5 magnet occupies the foremost position as it offers a unique combination of high energy product, coercivity and curie temperature. The SmCo 5 magnets are thus extensively used for high field applications. These are also best suited for use in environments where high demagnetizing field and high temperature are operative. Also, for applications where high performance and miniaturization are the over-riding considerations, the choice again falls on SmCo 5 magnets. The main deterrent to the widespread use of SmCo 5 magnet is its high cost. Both samarium and cobalt metals are high priced, and the magnets prepared from their directly melted alloy are thus naturally very expensive. An alternate process involving calcium reduction of their oxide intermediates has, therefore, been studied and the alloy prepared by this process has been evaluated and found satisfactory for magnet production. The process essentially involves compaction of the charge mix containing samarium oxide, cobalt oxide (or metal) and calcium metal and reduction of the charge compact at 1000-1300 degrees C in hydrogen atmosphere, followed by water and acid leaching, drying and classification

Samarium oxide as a radiotracer to evaluate the in vivo biodistribution of PLGA nanoparticles

CSIR Research Space (South Africa)

Mandiwana, V

2015-09-01

Full Text Available the biodistribution of poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles containing samarium-153 oxide ([(sup153)Sm]Sm(sub2)O(sub3)) in vivo to prove that orally administered nanoparticles alter the biodistribution of a drug. These were then activated in a nuclear...

Synthesis of Samarium Cobalt Nanoblades

Energy Technology Data Exchange (ETDEWEB)

Darren M. Steele

2010-08-25

As new portable particle acceleration technologies become feasible the need for small high performance permanent magnets becomes critical. With particle accelerating cavities of a few microns, the photonic crystal fiber (PCF) candidate demands magnets of comparable size. To address this need, samarium cobalt (SmCo) nanoblades were attempted to be synthesized using the polyol process. Since it is preferable to have blades of 1-2 {micro}m in length, key parameters affecting size and morphology including method of stirring, reaction temperature, reaction time and addition of hydroxide were examined. Nanoparticles consisting of 70-200 nm spherical clusters with a 3-5 nm polyvinylpyrrolidone (PVP) coating were synthesized at 285 C and found to be ferromagnetic. Nanoblades of 25nm in length were observed at the surface of the nanoclusters and appeared to suggest agglomeration was occurring even with PVP employed. Morphology and size were characterized using a transmission electron microscope (TEM). Powder X-Ray Diffraction (XRD) analysis was conducted to determine composition but no supportive evidence for any particular SmCo phase has yet been observed.

Neutron Capture and Transmission Measurements and Resonance Parameter Analysis of Samarium

International Nuclear Information System (INIS)

Leinweber, G.; Burke, J.A.; Knox, H.D.; Drindak, N.J.; Mesh, D.W.; Haines, W.T.; Ballad, R.V.; Block, R.C.; Slovacek, R.E.; Werner, C.J.; Trbovich, M.J.; Barry, D.P.; Sato, T.

2001-01-01

The purpose of the present work is to accurately measure the neutron cross sections of samarium. The most significant isotope is 149 Sm, which has a large neutron absorption cross section at thermal energies and is a 235 U fission product with a 1% yield. Its cross sections are thus of concern to reactor neutronics. Neutron capture and transmission measurements were performed by the time-of-flight technique at the Rensselaer Polytechnic institute (RPI) LINAC facility using metallic and liquid Sm samples. The capture measurements were made at the 25 meter flight station with a multiplicity-type capture detector, and the transmission total cross-section measurements were performed at 15- and 25-meter flight stations with 6 Li glass scintillation detectors. Resonance parameters were determined by a combined analysis of six experiments (three capture and three transmission) using the multi-level R-matrix Bayesian code SAMMY version M2. The significant features of this work are as follows. Dilute samples of samarium nitrate in deuterated water (D 2 O) were prepared to measure the strong resonances at 0.1 and 8 eV without saturation. Disk-shaped spectroscopic quartz cells were obtained with parallel inner surfaces to provide a uniform thickness of solution. The diluent feature of the SAMMY program was used to analyze these data. The SAMMY program also includes multiple scattering corrections to capture yield data and resolution functions specific to the RPI facility. Resonance parameters for all stable isotopes of samarium were deduced for all resonances up to 30 eV. Thermal capture cross-section and capture resonance integral calculations were made using the resultant resonance parameters and were compared to results obtained using resonance parameters from ENDF/B-VI updated through release 3. Extending the definition of the capture resonance integral to include the strong 0.1 eV resonance in 149 Sm, present measurements agree within estimated uncertainties with En

Identification of the lines in the L emission spectrum of cerium and samarium

International Nuclear Information System (INIS)

Shrivastava, B.D.; Singh, D.

1992-01-01

The occurrence of a line at 2.1556 A in the L emission spectrum of cerium and two lines at 1.6679 and 1.8379 A in the L emission spectrum of samarium, reported many years ago, has remained a puzzle. These have now been identified as EXAFS minima occurring at the L absorption edges of the respective elements. (author)

Samarium-153-EDTMP in the metastatic bone pain treatment

International Nuclear Information System (INIS)

Lins Filho, M.L.M.; Santos, A.O.; Nappi, A.P.B.; Meirelles, M.B.; Arouca, P.T.; Ramos, C.D.; Etchebehere, E.C.S.C.; Teixeira, L.C.; Netto Junior, N.R.; D'Ancona Cal; Camargo, E.E.

1997-01-01

Full text: Bone metastasis is the most reason of pain in prostate and mammary cancer patients. The Samarium-153-EDTMP has been showed as an alternative to the treatment of the metastasis bone pain. With the objective to evaluate the use of the Sm-153-EDTMP as a systemic therapy for the metastasis bone pain, 30 patients (19 male, 11 female, average age of 64,5 years) were studied. 19 patients with prostate cancer and 11 with mammary cancer. All the patients presented previous bone scintiscanning with multiple metastasis; interruption of the chemotherapy or radiotherapy for two or more weeks and leukocyte count higher than 2,000 leukocytes/mm 3 and platelets higher than 80,000/mm 3 . The patients were classified previously to the radioisotope therapy, as far the intensity of the pain in a scale from 0 to 10 is concerned. All the patients received 37 MBq/kg (1m Ci/kg) of weight of Sm-153-EDTMP by venous via. The evaluation 6 weeks after the therapy showed complete or partial pain relief in 22 patients (73,3%). Complete or partial pain relief has been obtained in 91,0% (10 in 11) of the patients with mammary cancer and in 62,2% (12 in 19) of the patients with prostate cancer. Transitory leukopenia (lower than 2,000 leukocytes/mm 3 ) and platelet count (lower than 80,000/mm 3 ) occurred in 33,3% of the patients. 8 patients (26,7%) did not responded to the therapy. The therapy with Samarium-153-EDTMP is a simple, safe and efficient method in the treatment of the bone pain caused by metastasis

Dependence of samarium-soil interaction on samarium concentration: Implications for environmental risk assessment.

Science.gov (United States)

Ramírez-Guinart, Oriol; Salaberria, Aitor; Vidal, Miquel; Rigol, Anna

2018-03-01

The sorption and desorption behaviour of samarium (Sm), an emerging contaminant, was examined in soil samples at varying Sm concentrations. The obtained sorption and desorption parameters revealed that soil possessed a high Sm retention capacity (sorption was higher than 99% and desorption lower than 2%) at low Sm concentrations, whereas at high Sm concentrations, the sorption-desorption behaviour varied among the soil samples tested. The fractionation of the Sm sorbed in soils, obtained by sequential extractions, allowed to suggest the soil properties (pH and organic matter solubility) and phases (organic matter, carbonates and clay minerals) governing the Sm-soil interaction. The sorption models constructed in the present work along with the sorption behaviour of Sm explained in terms of soil main characteristics will allow properly assessing the Sm-soil interaction depending on the contamination scenario under study. Moreover, the sorption and desorption K d values of radiosamarium in soils were strongly correlated with those of stable Sm at low concentrations (r = 0.98); indicating that the mobility of Sm radioisotopes and, thus, the risk of radioactive Sm contamination can be predicted using data from low concentrations of stable Sm. Copyright © 2017 Elsevier Ltd. All rights reserved.

Thermomechanical behavior of Fe-Mn-Si-Cr-Ni shape memory alloys modified with samarium

International Nuclear Information System (INIS)

Shakoor, R.A.; Khalid, F. Ahmad

2009-01-01

The deformation and training behavior of Fe-14Mn-3Si-10Cr-5Ni (wt.%) shape memory alloys containing samarium addition has been studied in the iron-based shape memory alloys. It is noticed that thermomechanical treatment (training) has significant influence on proof stress, critical stress and shape memory behavior of the alloys. The improvement in shape memory behavior can be attributed to the decrease in the proof stress and critical stress which facilitates the formation of ε (hcp martensite). It is also observed that alloy 2 containing samarium undergoes less softening as compared to alloy 1 with training which inhibits the formation of α (bcc martensite) and thus enhances the shape memory behavior. The excessive thermomechanical treatment with increase in the training cycle has led to the formation of α (bcc martensite) along with ε (hcp martensite) in the alloy 1 which appeared to have decline in the shape memory effect. This has been demonstrated by the examination of microstructure and identification of α (bcc martensite) martensite in the alloy 1 as compared to alloy 2

Effective visible light-active nitrogen and samarium co-doped BiVO4 for the degradation of organic pollutants

International Nuclear Information System (INIS)

Wang, Min; Niu, Chao; Liu, Jun; Wang, Qianwu; Yang, Changxiu; Zheng, Haoyan

2015-01-01

Nitrogen and samarium co-doped BiVO 4 (N–xSm–BiVO 4 ) nanoparticles were synthesized using a sol–gel method with a corn stem template. The physicochemical properties of the resultant N–xSm–BiVO 4 particles were characterized using various methods: XPS, XRD, SEM, BET, and UV–Vis DRS analyses. The visible-light photocatalytic activity was successfully demonstrated by degrading a model dye, namely, methyl orange. The dopant content was optimized, and the nitrogen and samarium co-doped BiVO 4 extended the light absorption spectrum toward the visible region, significantly enhancing the photodegradation of the model dye. The Sm and N co-doped BiVO 4 exhibited the highest photocatalytic activity compared to materials with a single dopant or no dopant. The significantly enhanced photocatalytic activity of the N–Sm co-doped BiVO 4 under visible-light irradiation can be attributed to the synergistic effects of the nitrogen and samarium. - Highlights: • The N–Sm codoped BiVO 4 were synthesized using a sol–gel method with a corn stem template. • The N and Sm codoped BiVO 4 has excellent photocatalytic activity of methyl orange degradation. • The maximum activity was observed when the molar ratio of Sm/Bi was 1.0. • The high photocatalytic activity was caused by the synergistic effects between N doping and Sm doping

Electrochemical extraction of samarium from molten chlorides in pyrochemical processes

International Nuclear Information System (INIS)

Castrillejo, Y.; Fernandez, P.; Medina, J.; Hernandez, P.; Barrado, E.

2011-01-01

This work concerns the electrochemical extraction of samarium from molten chlorides. In this way, the electrochemical behaviour of samarium ions has been investigated in the eutectic LiCl-KCl at the surface of tungsten, aluminium and aluminium coated tungsten electrodes. On a W inert electrode the electro-reduction of Sm(III) takes place in only one soluble-soluble electrochemical step Sm(III)/Sm(II). The electrochemical system Sm(II)/Sm(0) has not been observed within the electrochemical window, because of the prior reduction of Li(I) ions from the solvent, which inhibits the electro-extraction of Sm species from the salt on such a substrate. Sm metal in contact with the melt react to give Li(0) according to the reaction: Sm(0) + 2Li(I) ↔ Sm(II) + 2Li(0). On the contrary, on reactive Al electrodes the electrochemical system Sm(II)/Sm(0) was observed within the electroactive range. The potential shift of the redox couple is caused by the decrease of Sm activity in the metal phase due to the formation of Sm-Al alloys at the interface. The formation mechanism of the intermetallic compounds was studied in a melt containing: (i) both Sm(III) and Al(III) ions, using W and Al coated tungsten electrodes, and (ii) Sm(III) ions using an Al electrode. Analysis of the samples after potentiostatic electrolysis by X-ray diffraction and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), allowed the identification of Al 3 Sm and Al 2 Sm.

Electrochemical extraction of samarium from molten chlorides in pyrochemical processes

Energy Technology Data Exchange (ETDEWEB)

Castrillejo, Y., E-mail: ycastril@qa.uva.es [QUIANE/Dept Quimica Analitica, F. de Ciencias, Universidad de Valladolid, Prado de la Magdalena s/n, 47005 Valladolid (Spain); Fernandez, P. [QUIANE/Dept Quimica Analitica, F. de Ciencias, Universidad de Valladolid, Prado de la Magdalena s/n, 47005 Valladolid (Spain); Medina, J. [Dept Fisica Materia Condensada Cristalografia y Mineralogia, F. de Ciencias, Universidad de Valladolid, Prado de la Magdalena s/n, 47005 Valladolid (Spain); Hernandez, P. [Centro de Investigaciones Quimicas, Universidad Autonoma del Estado de Hidalgo, Carr. Pachuca-Tulancingo Km. 4.5, C.P. 42076 Pachuca, Hidalgo (Mexico); Barrado, E. [QUIANE/Dept Quimica Analitica, F. de Ciencias, Universidad de Valladolid, Prado de la Magdalena s/n, 47005 Valladolid (Spain)

2011-10-01

This work concerns the electrochemical extraction of samarium from molten chlorides. In this way, the electrochemical behaviour of samarium ions has been investigated in the eutectic LiCl-KCl at the surface of tungsten, aluminium and aluminium coated tungsten electrodes. On a W inert electrode the electro-reduction of Sm(III) takes place in only one soluble-soluble electrochemical step Sm(III)/Sm(II). The electrochemical system Sm(II)/Sm(0) has not been observed within the electrochemical window, because of the prior reduction of Li(I) ions from the solvent, which inhibits the electro-extraction of Sm species from the salt on such a substrate. Sm metal in contact with the melt react to give Li(0) according to the reaction: Sm(0) + 2Li(I) {r_reversible} Sm(II) + 2Li(0). On the contrary, on reactive Al electrodes the electrochemical system Sm(II)/Sm(0) was observed within the electroactive range. The potential shift of the redox couple is caused by the decrease of Sm activity in the metal phase due to the formation of Sm-Al alloys at the interface. The formation mechanism of the intermetallic compounds was studied in a melt containing: (i) both Sm(III) and Al(III) ions, using W and Al coated tungsten electrodes, and (ii) Sm(III) ions using an Al electrode. Analysis of the samples after potentiostatic electrolysis by X-ray diffraction and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), allowed the identification of Al{sub 3}Sm and Al{sub 2}Sm.

Resonances of coherent population trapping in samarium vapours

International Nuclear Information System (INIS)

Kolachevsky, Nikolai N; Akimov, A V; Kiselev, N A; Papchenko, A A; Sorokin, Vadim N; Kanorskii, S I

2001-01-01

Resonances of coherent population trapping were detected in atomic vapours of the rare-earth element samarium. The coherent population trapping was produced by two external-cavity diode lasers (672 and 686 nm) in a Λ-system formed by the three levels of 154 Sm: the 4f 6 6s 2 ( 7 F 0 ) ground state, the first fine-structure 4f 6 6s 2 ( 7 F 1 ) sublevel of the ground state and the 4f 6 ( 7 F)6s6p( 3 P o ) 9 F o 1 upper level. The dependence of the spectral shapes and resonance contrasts on the polarisation of the laser beams and the direction of the applied magnetic field was studied. The obtained results were analysed. (nonlinear optical phenomena)

The systems lanthanum (cerium, samarium) nitrate-tetramethyl-ammonium nitrate-water

International Nuclear Information System (INIS)

Zhuravlev, E.F.; Khisaeva, D.A.; Semenova, Eh.B.

1984-01-01

The method of cross sections at 25 and 50 deg C has been applied to study solubility in the systems lanthanum nitrate-tetramethyl ammonium nitrate-water (1), cesium (3) nitrate-tetramethyl ammonium nitrate-water (2) and samarium nitrate-tetramethyl ammonium nitrate-water (3). Crystallization fields of congruently dissolving compounds with 1:3 ratio of salt components (in system 1) and 1:2 ratio (in systems 2 and 3) are found in the systems. New solid phases are separated preparatively and subjected to chemical, differential thermal and IR spectroscopic analyses. Compositions of formed compounds are compared with the compositions known for nitrates of other representatives of light lanthanides

The systems cerium(3) (samarium) nitrate-quinoline nitrate-water

International Nuclear Information System (INIS)

Khisaeva, D.A.; Zhuravlev, E.F.; Semenova, Eh.B.

1982-01-01

Using the method of cross sections at 25 and 50 deg C the solubility in the systems cerium (3) nitrate-quinoline nitrate-water and samarium nitrate-quinoline nitrate-water has been studied. It is established that in the systems during chemical interaction of components congruently melting compounds of the composition: Ce(NO 3 ) 2 x2[C 9 H 7 NxHNO 3 ]x6H 2 O and Sm(NO 3 ) 3 x2[C 9 H 7 NxHNO 3 ]x2H 2 O are formed. New solid phases are separated preparatively and are subjected to chemical, differential thermal and IR spectroscopic analyses. The investigation results are compared with similar ones for nitrates of other representatives of lanthanide group

Body composition analysis by DEXA by using dynamically changing samarium filtration

DEFF Research Database (Denmark)

Gotfredsen, Arne; Baeksgaard, L; Hilsted, J

1997-01-01

Dual-energy X-ray absorptiometry (DEXA) has a high accuracy for body composition analysis but is influenced by beam hardening and other error sources in the extremes of measurement. To compensate for beam hardening, the Norland XR-36 introduces a dynamically changing samarium filtration system......). Scans of six healthy volunteers covered with combinations of beef and lard (approximately 5-15 kg) showed a good agreement (r = 0.99) between reference and DEXA values of added soft tissue mass and fat percentage. We conclude that the DEXA method (and, in particular, the Norland XR-36 using dynamic...

Effective visible light-active nitrogen and samarium co-doped BiVO{sub 4} for the degradation of organic pollutants

Energy Technology Data Exchange (ETDEWEB)

Wang, Min; Niu, Chao [College of Environmental and Chemical Engineering, Shenyang Ligong University, Shenyang 110165 (China); Liu, Jun, E-mail: minwang62@msn.com [Shenyang Military General Hospital, Shenyang 110016 (China); Wang, Qianwu; Yang, Changxiu; Zheng, Haoyan [College of Environmental and Chemical Engineering, Shenyang Ligong University, Shenyang 110165 (China)

2015-11-05

Nitrogen and samarium co-doped BiVO{sub 4} (N–xSm–BiVO{sub 4}) nanoparticles were synthesized using a sol–gel method with a corn stem template. The physicochemical properties of the resultant N–xSm–BiVO{sub 4} particles were characterized using various methods: XPS, XRD, SEM, BET, and UV–Vis DRS analyses. The visible-light photocatalytic activity was successfully demonstrated by degrading a model dye, namely, methyl orange. The dopant content was optimized, and the nitrogen and samarium co-doped BiVO{sub 4} extended the light absorption spectrum toward the visible region, significantly enhancing the photodegradation of the model dye. The Sm and N co-doped BiVO{sub 4} exhibited the highest photocatalytic activity compared to materials with a single dopant or no dopant. The significantly enhanced photocatalytic activity of the N–Sm co-doped BiVO{sub 4} under visible-light irradiation can be attributed to the synergistic effects of the nitrogen and samarium. - Highlights: • The N–Sm codoped BiVO{sub 4} were synthesized using a sol–gel method with a corn stem template. • The N and Sm codoped BiVO{sub 4} has excellent photocatalytic activity of methyl orange degradation. • The maximum activity was observed when the molar ratio of Sm/Bi was 1.0. • The high photocatalytic activity was caused by the synergistic effects between N doping and Sm doping.

Ferrites Ni0,5Zn0,5Fe2O4 doped with samarium: structural analysis, morphological and electromagnetic

International Nuclear Information System (INIS)

Costa, A.C.F.M.; Diniz, A.P.; Viana, K.M.S.; Cornejo, D.R.; Kiminami, R.H.G.A.

2010-01-01

This paper proposes to investigate the sintering at 1200 deg C/2h of Ni 0.5 Zn 0.5 Fe 2-x Sm x O 4 ferrite doped with 0.05; 0.075 e 0.1 mol of Sm synthesized by combustion reaction to evaluate the performance materials as absorbers of electromagnetic radiation. The influence of the concentration of samarium on the structure, morphology and electromagnetic properties of ferrites was studied. The resulting samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), magnetic measurements and reflectivity measurements in the frequency range between 8-12 GHz. The results showed that increasing the concentration of samarium caused a decrease in particle size of the samples, encouraging, therefore, to obtain materials with better values of magnetization and reflectivity, allowing for use as absorbers in narrow-band frequency between 9-10 GHz. (author)

Determination of micro amounts of samarium and europium by analogue derivative spectrophotometry

International Nuclear Information System (INIS)

Ishii, H.; Satoh, K.

1982-01-01

Derivative spectrophotometry using the analogue differentiation circuit was applied to the determination of samarium and europium at ppm levels. By measuring the second or the fourth derivative spectra of the characteristic absorption bands of both the rare earth ions around 400 nm, they can be determined directly and selectively in the presence of large amounts of most other rare earths without any prior separation. Further, aptly selecting conditions for the measurement of the derivative spectra, the simultaneous determination of both the rare earth elements was feasible. The principle and the characteristics of analogue derivative spectrophotometry are also described. (orig.) [de

New reduced variant in gadolinium and samarium monoxide thin films

Energy Technology Data Exchange (ETDEWEB)

Bist, B M.S.; Kumar, J; Srivastava, O N [Banaras Hindu Univ. (India). Dept. of Physics

1977-01-01

A new reduced phase has been observed in the thin films of gadolinium and samarium monoxides. This phase results on imparting an annealing treatment to the monoxides and is formed as a result of the creation and ordering of vacancies in the oxygen sublattice. The new phase has been analysed to possess a rhombohedral unit cell with lattice parameters a/sub R/ = a/sub 0/ square root of (3/2) and c/sub R/ = a/sub 0/ square root of 3 (based on hexagonal axes, a/sub 0/ being the lattice parameter of the fundamental zinc blende type unit cell of the monoxide). Based on the proposed structure, the new phase can be assigned the solid state chemical formula RO/sub x/ where R = Gd, Sm and x = 0.66.

Enhanced electron-lattice coupling under uniaxial stress in layered double hydroxides intercalated with samarium complexes

International Nuclear Information System (INIS)

Park, Ta-Ryeong

2004-01-01

We have applied uniaxial stress to samarium complexes by intercalating them into the gallery of a layered material and by using a diamond-anvil cell at 28 K. Although uniaxial stress reduces symmetry and removes degeneracy, the overall number of photoluminescence (PL) peaks evidently decreased with the application of uniaxial stress. This contradictory observation is explained by an increased electron-lattice coupling strength under uniaxial stress. This behavior is also confirmed by time-resolved PL data.

Phase Composition of Samarium Niobate and Tantalate Thin Films Prepared by Sol-Gel Method

Science.gov (United States)

Bruncková, H.; Medvecký, Ľ.; Múdra, E.; Kovalčiková, A.; Ďurišin, J.; Šebek, M.; Girman, V.

2017-12-01

Samarium niobate SmNbO4 (SNO) and tantalate SmTaO4 (STO) thin films ( 100 nm) were prepared by sol-gel/spin-coating process on alumina substrates with PZT interlayer and annealing at 1000°C. The precursors of films were synthesized using Nb or Ta tartrate complexes. The improvement of the crystallinity of monoclinic M'-SmTaO4 phase via heating was observed through the coexistence of small amounts of tetragonal T-SmTa7O19 phase in STO precursor at 1000°C. The XRD results of SNO and STO films confirmed monoclinic M-SmNbO4 and M'-SmTaO4 phases, respectively, with traces of orthorhombic O-SmNbO4 (in SNO). In STO film, the single monoclinic M'-SmTaO4 phase was revealed. The surface morphology and topography of thin films were investigated by SEM and AFM analysis. STO film was smoother with roughness 3.2 nm in comparison with SNO (6.3 nm). In the microstructure of SNO film, small spherical ( 50 nm) and larger cuboidal particles ( 100 nm) of the SmNbO4 phase were observed. In STO, compact clusters composed of fine spherical SmTaO4 particles ( 20-50 nm) were found. Effect of samarium can contribute to the formation different polymorphs of these films for the application to environmental electrolytic thin film devices.

Evaluation of samarium-153 and holmium-166-EDTMP in the normal baboon model

Energy Technology Data Exchange (ETDEWEB)

Louw, W.K.A.; Dormehl, I.C.; Rensburg, A.J. van; Hugo, N.; Alberts, A.S.; Forsyth, O.E.; Beverley, G.; Sweetlove, M.A.; Marais, J.; Loetter, M.G.; Aswegen, A. van

1996-11-01

Bone-seeking radiopharmaceuticals such as ethylenediaminetetramethylene phosphonate (EDTMP) complexes of samarium-153 and holmium-166 are receiving considerable attention for therapeutic treatment of bone metastases. In this study, using the baboon experimental model, multicompartmental analysis revealed that with regard to pharmacokinetics, biodistribution, and skeletal localisation, {sup 166}Ho-EDTMP was significantly inferior to {sup 153}Sm-EDTMP and {sup 99m}Tc-MDP. A more suitable {sup 166}Ho-bone-seeking agent should thus be sought for closer similarity to {sup 153}Sm-EDTMP to exploit fully the therapeutic potential of its shorter half-life and more energetic beta radiation.

Performance analysis of samarium cobalt P.M. synchronous motor fed from PWM inverters

International Nuclear Information System (INIS)

Rahman, M.A.; Choudhury, M.A.

1985-01-01

This paper presents an analysis and performance of samarium cobalt permanent magnet (P.M.) synchronous motors fed from two types of voltage source pulse width modulated (PWM) inverters. The analysis and test results on the steady state performance of a P.M. motor fed from PWM inverters are presented. PWM inverters are used in variable voltage variable frequency applications to avoid a double conversion process of ordinary inverters. In drives, they are used for voltage and speed regulation of motors. Use of modulation technique in inverters also allow to eliminate or minimize selected harmonics from the inverter output voltage

JAEA thermodynamic database for performance assessment of geological disposal of high-level and TRU wastes. Refinement of thermodynamic data for trivalent actinoids and samarium

International Nuclear Information System (INIS)

Kitamura, Akira; Fujiwara, Kenso; Yui, Mikazu

2010-01-01

Within the scope of the JAEA thermodynamic database project for performance assessment of geological disposal of high-level radioactive and TRU wastes, the refinement of the thermodynamic data for the inorganic compounds and complexes of trivalent actinoids (actinium(III), plutonium(III), americium(III) and curium(III)) and samarium(III) was carried out. Refinement of thermodynamic data for these elements was based on the thermodynamic database for americium published by the Nuclear Energy Agency in the Organisation for Economic Co-operation and Development (OECD/NEA). Based on the similarity of chemical properties among trivalent actinoids and samarium, complementary thermodynamic data for their species expected under the geological disposal conditions were selected to complete the thermodynamic data set for the performance assessment of geological disposal of radioactive wastes. (author)

Retention capacity of samarium (III) in zircon for it possible use in retaining walls for confinement of nuclear residues

International Nuclear Information System (INIS)

Garcia G, N.

2006-01-01

Mexico, as country that produces part of its electric power by nuclear means, should put special emphasis in the development of technologies guided to the sure and long term confinement of the high level nuclear residuals. This work studies the capacity that has the natural zircon to retain to the samarium (III) in solution, by what due, firstly, to characterize the zircon for technical instrumental to determine the purity and characteristic of the mineral in study. The instrumental techniques that were used to carry out the physicochemical characterization were the neutron activation analysis (NAA), the infrared spectroscopy (IS), the thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), semiquantitative analysis, dispersive energy spectroscopy (EDS), X-ray diffraction (XRD) and luminescence technique. The characterization of the surface properties carries out by means of the determination of the surface area using the BET multipoint technique, acidity constants, hydration time, the determination of the point of null charge (pH PCN ) and density of surface sites (D s ). The luminescence techniques were useful to determine the optimal point hydration of the zircon and for the quantification of the samarium, for that here intends the development of both analysis techniques. With the adjustment of the titration curves in the FITEQL 4 package the constants of surface acidity in the solid/liquid interface were determined. To the finish of this study it was corroborated that the zircon is a mineral that presents appropriate characteristics to be proposed as a contention barrier for the deep geologic confinement. With regard to the study of adsorption that one carries out the samarium retention it is superior to 90% under the described conditions. This investigation could also be applicable in the confinement of dangerous industrial residuals. (Author)

Optical properties and electronic transitions of zinc oxide, ferric oxide, cerium oxide, and samarium oxide in the ultraviolet and extreme ultraviolet

DEFF Research Database (Denmark)

Pauly, N; Yubero, F; Espinós, J P

2017-01-01

Optical properties and electronic transitions of four oxides, namely zinc oxide, ferric oxide, cerium oxide, and samarium oxide, are determined in the ultraviolet and extreme ultraviolet by reflection electron energy loss spectroscopy using primary electron energies in the range 0.3-2.0 ke...

Magnetic behavior study of samarium nitride using density functional theory

Science.gov (United States)

Som, Narayan N.; Mankad, Venu H.; Dabhi, Shweta D.; Patel, Anjali; Jha, Prafulla K.

2018-02-01

In this work, the state-of-art density functional theory is employed to study the structural, electronic and magnetic properties of samarium nitride (SmN). We have performed calculation for both ferromagnetic and antiferromagnetic states in rock-salt phase. The calculated results of optimized lattice parameter and magnetic moment agree well with the available experimental and theoretical values. From energy band diagram and electronic density of states, we observe a half-metallic behaviour in FM phase of rock salt SmN in while metallicity in AFM I and AFM III phases. We present and discuss our current understanding of the possible half-metallicity together with the magnetic ordering in SmN. The calculated phonon dispersion curves shows dynamical stability of the considered structures. The phonon density of states and Eliashberg functional have also been analysed to understand the superconductivity in SmN.

Myelotoxicity of Samarium Sm153 lexidronam in patients with painful bony metastases

International Nuclear Information System (INIS)

Ben Ghachem, T.; Mhiri, A.; Slim, I.; Bahloul, A.; Yeddes, I.; Elbez, I.; Meddeb, I.; Ben Slimene, M.F.

2015-01-01

Full text of publication follows. Introduction: the management of bone pain includes analgesia, radiation, hormones, radiofrequency (RF) ablation, chemotherapy, and surgery. Bone pain palliation therapy with radiopharmaceuticals is a cost-effective systemic therapy to relieve pain from skeletal metastases with a consequent decrease in morbidity and an improvement in quality of life. The aim of our study is to evaluate the effect of myelotoxicity of samarium lexidronam (Sm 153 ) in patients with painful bony metastasis. Methods: we reviewed 116 patients aged from 14 to 87 years old, 91 males (78%) and 25 females (22%), having received 1 to 4 treatments of Sm 153 (37 MBq/kg) for painful bony metastases from different primitive tumors: 67 cases of prostate cancer (57.7%), 22 cases of breast cancer (18.9%), 10 cases of pulmonary cancer (8.6%) and others in 14.6% of cases. Clinical follow-up was available for 159 treatments, consisting on blood count each week over at least two months, in order to evaluate myelotoxicity according to WHO classification. Results: no patients had grade 4 toxicity after its cures. A grade 2-3 myelotoxicity was observed after 52 treatments (34%) during the second week and after 50 treatments (32.6%) during the fourth week with a satisfactory reversibility. At 10 weeks of treatment, myelotoxicity was reclassified from 0 to 2 for 139 cures (90,8%). Moreover, we found that prior treatment with radiotherapy or chemotherapy did not affect the rates of myelotoxicity. Conclusion: multiple treatments with samarium Sm 153 lexidronam had no significant effect on myelotoxicity. Patients with bone predominant metastatic disease may survive for extended periods of time and may safely be treated with multiple modalities of therapy. (authors)

Preparation and biological behaviour of samarium-153-hydroxyapatite particles for radiation synovectomy

International Nuclear Information System (INIS)

Agrueelles, M.G.; Luppi Berlanga, I.S.; Torres, E.A.; Rutty Sola, G.A.; Rimoldi, G.

1998-01-01

The preparation and labelling procedures of 153 Sm-hydroxyapatite ( 153 Sm-HA) are described in this paper. Hydroxyapatite (HA) was prepared and studied as a radiosynovectomy agent. HA particles were prepared from the reaction of calcium nitrate and ammonia phosphate at high pH Samarium-153 labelling was done in two steps with citric acid. A serie of experimental conditions, such as specific activity, citric acid mass, radioactive solution volume, in-vitro stability, have been carried out. Radiolabelling efficiency was greater than 95%. In vitro studies showed high stability (≥99%). Animal studies showed a good retention in the synovium, with a very low extra-articular leakage over 6 days after administration. (author)

Fabrication of a PVC membrane samarium(III) sensor based on N,N′,N″-tris(4-pyridyl)trimesic amide as a selectophore

International Nuclear Information System (INIS)

Zamani, Hassan Ali; Naghavi-Reyabbi, Fatemeh; Faridbod, Farnoush; Mohammadhosseini, Majid; Ganjali, Mohammad Reza; Tadjarodi, Azadeh; Rad, Maryam

2013-01-01

A new ion-selective electrode for Sm 3+ ion is described based on the incorporation of N,N′,N″-tris(4-pyridyl)trimesic amide (TPTA) in a poly(vinylchloride) (PVC) matrix. The membrane sensor comprises nitrobenzene (NB) as a plasticizer, and oleic acid (OA) as an anionic additive. The sensor with the optimized composition shows a Nernstian potential response of 19.8 ± 0.5 mV decade −1 over a wide concentration range of 1.0 × 10 −2 and 1 × 10 −6 mol L −1 , with a lower detection limit of 4.7 × 10 −7 mol L −1 and satisfactor applicable pH range of 3.6–9.2. Having a short response time of less than 10 s and a very good selectivity towards the Sm 3+ over a wide variety of interfering cations (e.g. alkali, alkaline earth, transition and heavy metal ions) the sensor seemed to be a promising analytical tool for determination of the Sm 3+ . Hence, it was used as an indicator electrode in the potentiometric titration of samarium ion with EDTA. It was also applied to the direct samarium recovery in binary mixtures. - Highlights: ► A new Sm 3+ -PVC membrane sensor is introduced for determination of Sm 3+ ions in the solutions. ► N,N′,N″-tris(4-pyridyl)trimesic amide was used as a suitable selectophore for samarium sensor. ► Detection limit of the sensor is 4.7 × 10 −7 mol L −1 with a short response time of less than 10 s.

Optical and physical properties of samarium doped lithium diborate glasses

Science.gov (United States)

Hanumantharaju, N.; Sardarpasha, K. R.; Gowda, V. C. Veeranna

2018-05-01

Sm3+ doped lithium di-borate glasses with composition 30Li2O-60B2O3-(10-x) PbO, (where 0 molar volume with samarium ion content indicates the openness of the glass structure. The gradual increase in average separation of boron-boron atoms with VmB clearly indicates deterioration of borate glass network, which in turn leads to decrease in the oxygen packing density. The replacements of Sm2O3 for PbO depolymerise the chain structure and that would increase the concentration of non-bridging oxygens. The marginal increase of optical band gap energy after 1.0 mol.% of Sm2O3 is explained by considering the structural modification in lead-borate. The influence of Sm3+ ion on physical and optical properties in lithium-lead-borate glasses is investigated and the results were discussed in view of the structure of borate glass network.

Preparation and examination of properties of samarium-153-EDTMP complex; Otrzymywanie chelatu kwasu etylenodiaminotetrametylenofosfonowego (EDTMP) z samarem-153 i badanie jego wlasciwosci

Energy Technology Data Exchange (ETDEWEB)

Nowak, M. [Institute of Atomic Energy, Otwock-Swierk (Poland); Garnuszek, P.; Lukasiewicz, A.; Wozniak, I.; Zulczyk, W. [Osrodek Badawczo-Rozwojowy Izotopow, Otwock-Swierk (Poland); Licinska, I. [Instytut Lekow, Warsaw (Poland)

1995-12-31

Preparation and properties of ethylenediaminetetramethylenephosphonic acid (EDTMP) as well as some properties of {sup 153}Sm-EDTMP chelate have been examined. The chelate formed by samarium-153 (46.3 h, {beta}{sup -}-decay) with EDTMP exhibits high bone uptake and can be used for treatment of disseminated, painful skeletal metastases. The purity and stability of solutions of {sup 153}Sm-EDTMP chelate were examined in a broad range of samarium concentration and {sup 153}Sm specific activity. The complex under study was examined by radio-TLC, -electrophoresis and radio-HPLC. The results obtained suggest the small size of molecules of {sup 153}Sm-EDTMP chelate as compared with molecules of ``free``EDTMP. The results of biodistribution of {sup 153}Sm-EDTMP determined in rats indicate the quick blood clearance, high deposition of radioactivity in bone and quick excretion of radioactivity into urine. No specific uptake of {sup 153}Sm-EDTMP in extra-skeletal organs was found. (author). 42 refs, 13 figs, 22 tabs.

Potentiometric study of samarium oxides formation from its chloride in a molten eutectic mixture of sodium and cesium chlorides

International Nuclear Information System (INIS)

Smolenskij, V.V.; Bove, A.L.; Del'mukhamedov, R.D.; Borodina, N.P.; Gavrilov, A.G.

1997-01-01

Interaction of trivalent samarium cations with oxide-ions in NaCl-2CsCl melt at 973 K has been studied by potentiometric method using electrochemical cell with two platinum-oxygen electrodes with a solid electrolyte membrane. The mechanism of the interaction and composition of the reaction products, depending on the medium oxyacidity, have been considered. Certain thermodynamic characteristics of the process have been calculated

Structural phase transition and electronic properties in samarium chalcogenides

Energy Technology Data Exchange (ETDEWEB)

Panwar, Y. S., E-mail: yspanwar2011@gmail.com [Department of Physics, Govt. New Science College Dewas-455001 (India); Aynyas, Mahendra [Department of Physics, C.S.A. Govt. P.G. College, Sehore, 466001 (India); Pataiya, J.; Sanyal, Sankar P. [Department of Physics, Barkatullah University, Bhopal, 462026 (India)

2016-05-06

The electronic structure and high pressure properties of samarium monochalcogenides SmS, SmSe and SmTe have been reported by using tight binding linear muffin-tin-orbital (TB-LMTO) method within the local density approximation (LDA). The total energy as a function of volume is evaluated. It is found that these monochalcogenides are stable in NaCl-type structure under ambient pressure. We predict a structural phase transition from NaCl-type (B{sub 1}-phase) structure to CsCl-type (B{sub 2}-type) structure for these compounds. Phase transition pressures were found to be 1.7, 4.4 and 6.6 GPa, for SmS, SmSe and SmTe respectively. Apart from this, the lattice parameter (a{sub 0}), bulk modulus (B{sub 0}), band structure (BS) and density of states (DOS) are calculated. From energy band diagram we observed that these compounds exhibit metallic character. The calculated values of equilibrium lattice parameter and phase transition pressure are in general good agreement with available data.

Sorption of samarium in iron (II) and (III) phosphates in aqueous systems; Sorcion de samario en fosfatos de hierro (II) y (III) en sistemas acuosos

Energy Technology Data Exchange (ETDEWEB)

Diaz F, J C

2006-07-01

The radioactive residues that are stored in the radioactive confinements its need to stay isolated of the environment while the radioactivity levels be noxious. An important mechanism by which the radioactive residues can to reach the environment, it is the migration of these through the underground water. That it makes necessary the investigation of reactive materials that interacting with those radionuclides and that its are able to remove them from the watery resources. The synthesis and characterization of materials that can be useful in Environmental Chemistry are very important because its characteristics are exposed and its behavior in chemical phenomena as the sorption watery medium is necessary to use it in the environmental protection. In this work it was carried out the sorption study of the samarium III ion in the iron (II) and (III) phosphate; obtaining the sorption isotherms in function of pH, of the phosphate mass and of the concentration of the samarium ion using UV-visible spectroscopy to determine the removal percentage. The developed experiments show that as much the ferrous phosphate as the ferric phosphate present a great affinity by the samarium III, for what it use like reactive material in contention walls can be very viable because it sorption capacity has overcome 90% to pH values similar to those of the underground and also mentioning that the form to obtain these materials is very economic and simple. (Author)

Separation of lanthanum from samarium on solid aluminum electrode in LiCl-KCl eutectic melts

International Nuclear Information System (INIS)

De-Bin Ji; Mi-Lin Zhang; Xing Li; Xiao-Yan Jing; Wei Han; Yong-De Yan; Yun Xue; Zhi-Jian Zhang; Harbin Engineering University, Harbin

2015-01-01

This paper presents an electrochemical study on the separation of lanthanum from samarium on aluminum electrode at 773 K. The results from different electrochemical methods showed that Sm(III) and La(III) formed Al-Sm and Al-La intermetallic compounds on an aluminum electrode at electrode potential around -1.67 and -1.46 V, respectively. The electrochemical separation of lanthanum was carried out in LiCl-KCl-LaCl 3 -SmCl 3 melts on solid aluminum electrodes at 773 K by potentiostatic electrolysis at -1.45 V for 40 h and the separation efficiency was 99.1 %. (author)

Structural and luminescence properties of samarium doped lead alumino borate glasses

Science.gov (United States)

Mohan, Shaweta; Kaur, Simranpreet; Singh, D. P.; Kaur, Puneet

2017-11-01

The study reports the effect of samarium concentration on the physical, structural and spectroscopic characteristics of samarium doped lead alumino borate glasses having composition 20PbO-(10-x)Al2O3-70B2O3-xSm2O3; x = 0.1, 0.5, 1.0 and 2.0 mol %. The glasses were fabricated by conventional melt-quenching technique and then characterized by XRD, FTIR, optical absorption and fluorescence spectra. X-ray diffraction studies confirmed the amorphous nature of the prepared glasses. FTIR spectra indicate the presence of BO3, BO4, AlO6 and a few other structural groups. Various physical properties such as density, molar volume, refractive index, rare earth ion concentration, boron-boron distance and polarizability etc. were determined using conventional methods and standard formulae. The Judd-Ofelt theory was applied on the optical absorption spectra of the glasses to evaluate the three phenomenological intensity parameters Ω2, Ω4 and Ω6. The value of Ω2 was found to be highest for glass with 1 mol% Sm2O3 and attributed to the asymmetry of the ligand field at the rare earth ion site and the rare earth oxygen (Sm-O) covalency. The calculated intensity parameters and fluorescence spectra were further used to predict the radiative transition probability (A), radiative lifetime (τR), branching ratio (βR), peak wavelength (λp), effective line widths (Δλeff) and stimulated emission cross-section (σ) for the characteristic 4G5/2 → 6H5/2, 6H7/2 and 6H9/2 transitions of the Sm3+ ion. Concentration quenching was observed for 2 mol% concentration of Sm2O3 and ascribed to energy transfer through various cross-relaxation channels between Sm3+ ions. Reasonably high values of branching ratios and stimulated emission cross-section for the prepared glasses points towards their utility in the development of visible lasers emitting in the reddish-orange spectral region. However, the glass with 1 mol% Sm2O3 was found to show better radiative properties.

Europium and samarium doped calcium sulfide thin films grown by PLD

International Nuclear Information System (INIS)

Christoulakis, S.; Suchea, M; Katsarakis, N.; Koudoumas, E

2007-01-01

Europium and samarium doped calcium sulfide thin films (CaS:Eu,Sm) with different thickness were prepared by the pulsed laser deposition technique using sintered targets. A typical homemade deposition chamber and XeCl excimer laser (308 nm) were employed and the films were deposited in helium atmosphere onto silicon and corning glass substrates. Structural investigations carried out by X-ray diffraction and atomic force microscopy showed a strong influence of the deposition parameters on the film properties. The films grown had an amorphous or polycrystalline structure depending on growth temperature and the number of pulses used, the same parameters affecting the film roughness, the grain shape and dimensions, the film thickness and the optical transmittance. This work indicates that pulsed laser deposition can be a suitable technique for the preparation of CaS:Eu,Sm thin films, the film characteristics being controlled by the growth conditions

The dynamics of the laser-induced metal-semiconductor phase transition of samarium sulfide (SmS)

International Nuclear Information System (INIS)

Kaempfer, Tino

2009-01-01

The present thesis is dedicated to the experimental study of the metal-semiconductor phase transition of samarium sulfide (SmS): Temperature- and time-resolved experiments on the characterization of the phase transition of mixed-valence SmS samples (M-SmS) are presented. The measurement of the dynamics of the laser-induced phase transition pursues via time-resolved ultrashort-time microscopy and by X-ray diffraction with sub-picosecond time resolution. The electronic and structural processes, which follow an excitation of M-SmS with infrared femtosecond laser pulses, are physically interpreted on the base of the results obtained in this thesis and model imaginations. [de

Samarium (III Selective Membrane Sensor Based on Tin (IV Boratophosphate

Directory of Open Access Journals (Sweden)

Ashok S. K. Kumar

2004-08-01

Full Text Available Abstract: A number of Sm (III selective membranes of varying compositions using tin (IV boratophosphate as electroactive material were prepared. Polyvinyl chloride, polystyrene and epoxy resin were used as binding materials. Membrane having composition of 40% exchanger and 60% epoxy resin exhibited best performance. This membrane worked well over a wide concentration range of 1x10-5M to 1x10-1 M of samarium ions with a Super-Nernstian slope of 40 mV/decade. It has a fast response time of less than 10 seconds and can be used for at least six months without any considerable divergence in potentials. The proposed sensor revealed good selectivities with respect to alkali, alkaline earth, some transition and rare earth metal ions and can be used in the pH range of 4.0-10.0. It was used as an indicator electrode in the potentiometric titration of Sm (III ions against EDTA. Effect of internal solution was studied and the electrode was successfully used in non-aqueous media, too.

Determination of trace amounts of rare earth elements in samarium, terbium and disprosium oxides by graphite furnace atomic-absorption spectrometry

International Nuclear Information System (INIS)

Dantas, E.S.K.

1990-01-01

A graphite furnace atomic-absorption spectrometry method for the determination of neodymium, europium, terbium, dysprosium and yttrium at trace level in samarium oxide; of samarium, europium, dysprosium, holmium, erbium and yttrium in terbium oxide and of europium, terbium, holmium, erbium and yttrium in dysprosium oxide was established. The best pyrolysis and atomization temperatures were determined for each lanthanide considered. Calibration curves were obtained for the pure elements, for binary mixtures formed by the matrix and each of the lanthanides studied and, finally, for the complex mixtures constituted by the matrix and all the other lanthanide of the group under scrutiny. This study has been carried out to examine the interference of the presence of one lanthanide on the behaviour of the other, since a lack of linearity on the calibration curves has been observed in some cases. Detection and determination limits have been determined as well. The detection limits encountered were within the range 0.002 to 0.3% for different elements. The precision of the method expressed as the relative standard deviation was calculated for each element present in each of the matrices studied. The conclusion arrived at is that the method can be applied for determining the above mentioned lanthanides present in the matrices studied with purity up to 99.50%. (author)

Synthesis of samarium complexes with the derivative binder of Schiff Quinolinic base. Characterization and photophysical study; Sintesis de complejos de samario con el ligante derivado de base de Schiff Quinolinica. Caracterizacion y estudio fotofisico

Energy Technology Data Exchange (ETDEWEB)

Lucas H, J.

2016-07-01

In this work we determined the metal: binder stoichiometry of the species formed during the UV/Vis spectrophotometric titration of the derivative binder of Schiff quinolinic base, L1 with the samarium nitrate pentahydrate in methanol. Statistical analysis of the data allowed proposing the metal: binder stoichiometry for the synthesis of the complexes which was one mole of samarium salt by 2.5 moles of binder and thus favor the formation of complexes with 1M: 1L and 1M: 2L stoichiometries. They were synthesized in aqueous-organic medium (water-ethanol), isolated and purified two complexes with stoichiometry 1 Sm: 1 L1, complex 1 and 1 Sm: 2 L1, complex 2. The overall yield of the reaction was 76%. The characterization of the formed complexes was performed by visible ultraviolet spectrometry (UV/Vis), nuclear magnetic resonance, X-ray photoelectron spectroscopy (XP S), thermal gravimetric analysis with differential scanning calorimetry (TGA/DSC), and radial distribution function. These complexes were studied by fluorescence and emission phosphorescence at variable temperature. Spectroscopic techniques used in both solution and solid demonstrated the formation and stability of these complexes. In addition XP S indicated that in both complexes the samarium retains its oxidation state 3+. Luminescence studies indicated that there is intra-binding charge transfer which decreases the transfer of light energy from the binder to the samarium. Based on the experimental results, L1 binder molecules and complexes 1 and 2 were modeled that demonstrated the proposed Nc for each complex, as well as allowed to visualize the structural arrangement of the molecules, complexes and binder. (Author)

Fabrication of a PVC membrane samarium(III) sensor based on N,N Prime ,N Double-Prime -tris(4-pyridyl)trimesic amide as a selectophore

Energy Technology Data Exchange (ETDEWEB)

Zamani, Hassan Ali, E-mail: haszamani@yahoo.com [Department of Applied Chemistry, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Naghavi-Reyabbi, Fatemeh [Resident of General Surgery, Endoscopic and Minimaly Invasive Surgery Research Center, Ghaem Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of); Faridbod, Farnoush [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Mohammadhosseini, Majid [Department of Chemistry, Faculty of Basic Sciences, Shahrood Branch, Islamic Azad University, Shahrood (Iran, Islamic Republic of); Ganjali, Mohammad Reza [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Tadjarodi, Azadeh; Rad, Maryam [Department of Chemistry, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)

2013-03-01

A new ion-selective electrode for Sm{sup 3+} ion is described based on the incorporation of N,N Prime ,N Double-Prime -tris(4-pyridyl)trimesic amide (TPTA) in a poly(vinylchloride) (PVC) matrix. The membrane sensor comprises nitrobenzene (NB) as a plasticizer, and oleic acid (OA) as an anionic additive. The sensor with the optimized composition shows a Nernstian potential response of 19.8 {+-} 0.5 mV decade{sup -1} over a wide concentration range of 1.0 Multiplication-Sign 10{sup -2} and 1 Multiplication-Sign 10{sup -6} mol L{sup -1}, with a lower detection limit of 4.7 Multiplication-Sign 10{sup -7} mol L{sup -1} and satisfactor applicable pH range of 3.6-9.2. Having a short response time of less than 10 s and a very good selectivity towards the Sm{sup 3+} over a wide variety of interfering cations (e.g. alkali, alkaline earth, transition and heavy metal ions) the sensor seemed to be a promising analytical tool for determination of the Sm{sup 3+}. Hence, it was used as an indicator electrode in the potentiometric titration of samarium ion with EDTA. It was also applied to the direct samarium recovery in binary mixtures. - Highlights: Black-Right-Pointing-Pointer A new Sm{sup 3+}-PVC membrane sensor is introduced for determination of Sm{sup 3+} ions in the solutions. Black-Right-Pointing-Pointer N,N Prime ,N Double-Prime -tris(4-pyridyl)trimesic amide was used as a suitable selectophore for samarium sensor. Black-Right-Pointing-Pointer Detection limit of the sensor is 4.7 Multiplication-Sign 10{sup -7} mol L{sup -1} with a short response time of less than 10 s.

Fluorometric determination of samarium and europium in rare earth minerals with. beta. -diketoneternary complex

Energy Technology Data Exchange (ETDEWEB)

Huang, H; Hiraki, K; Nishikawa, Y [Kinki Univ., Higashi-Osaka, Osaka (Japan). Faculty of Science and Technology

1981-07-01

This communication reported the optimum conditions for the fluorometric determination of these ions, and the method was adopted in the simultaneous determination of samarium and europium in xenotime and monazite minerals. From the experimental results on the effect of diverse ions and the extraction pH of the aqueous phase, it became clear that TTA-TOPO hexane method was the best system for the determination of samarium and europium because of the highest fluorescence sensitivity of the ternary complex, and also because the lower extraction pH eliminated the effect of diverse ions. Moreover, the very high detection limit (2 ppb) of Sm was achieved by the use of a red sensitive photomultiplier. Which was used at 644 nm, and that of Eu (0.02 ppb) at 614 nm. The procedure was established as follows: The rare earth minerals (xenotime, monazite) sample was treated with hot conc. H/sub 2/SO/sub 4/ and twice precipitated with 0.5 mol dm/sup -3/ oxalic acid (pH was adjusted to 2.0 -- 2.2). Then the precipitate was filtered and ignited to give the rare earth oxide. Fifty milligrams of the oxide was dissolved in HCl and diluted with water in order to obtain the solution containing 5 ..mu..g cm/sup -3/ rare earth oxide. An aliquot of the solution ((1.0 -- 3.0) cm/sup 3/) was adjusted to pH 5.5 with sodium acetate and shaken with 1 x 10/sup -4/ mol dm/sup -3/ TTA- 2 x 10/sup -2/ mol dm/sup -3/ TOPO hexane solution. Then the fluorescence intensity of the organic layer was measured at 644 nm for Sm and 614 nm for Eu. In this procedure, the recovery of Sm and Eu was found to be about 96%. Xenotime contained 0.70% of Sm and 0.004% of Eu, and monazite contained 1.84% of Sm and 0.003% of Eu.

Memory effect of calcined layered samarium hydroxy chlorides in aqueous solution

International Nuclear Information System (INIS)

Lee, Byung Il; Byeon, Song Ho

2015-01-01

The decomposition and recovery behavior of layered samarium hydroxychloride (Sm 2 (OH) 5 Cl·nH 2 O, LSmH) has been closely studied in various conditions. Although the heat treatment of LSmH at 700 °C completely collapsed typical layered structure, the calcined LSmH (c-LSmH) recovered its layered characteristics and consequently its ability to intercalate anions into the interlayer space when it was rehydroxylated and rehydrated in aqueous solutions containing organic and inorganic anions. This phenomenon is similar to the memory effect observed in classical layered double hydroxides (LDHs), where LDHs calcined to a mixture of metal oxides can recover their layered structures in aqueous solutions. In contrast, the recovery reaction of c-LSmH in water without any counter anions was unsuccessful and instead resulted in the formation of Sm(OH) 3 . Such a difference was interpreted on the basis of the salt effect on Sm 2 (OH) 5 Cl·nH 2 O–Sm(OH) 3 phase equilibria in water

A memristor-based third-order oscillator: beyond oscillation

KAUST Repository

Talukdar, Abdul Hafiz Ibne

2012-10-06

This paper demonstrates the first third-order autonomous linear time variant circuit realization that enhances parametric oscillation through the usage of memristor in conventional oscillators. Although the output has sustained oscillation, the linear features of the conventional oscillators become time dependent. The poles oscillate in nonlinear behavior due to the oscillation of memristor resistance. The mathematical formulas as well as SPICE simulations are introduced for the memristor-based phase shift oscillator showing a great matching.

A memristor-based third-order oscillator: beyond oscillation

KAUST Repository

Talukdar, Abdul Hafiz Ibne; Radwan, Ahmed G.; Salama, Khaled N.

2012-01-01

This paper demonstrates the first third-order autonomous linear time variant circuit realization that enhances parametric oscillation through the usage of memristor in conventional oscillators. Although the output has sustained oscillation, the linear features of the conventional oscillators become time dependent. The poles oscillate in nonlinear behavior due to the oscillation of memristor resistance. The mathematical formulas as well as SPICE simulations are introduced for the memristor-based phase shift oscillator showing a great matching.

The properties of samarium-doped zinc oxide/phthalocyanine structure for optoelectronics prepared by pulsed laser deposition and organic molecular evaporation

Czech Academy of Sciences Publication Activity Database

Novotný, Michal; Marešová, Eva; Fitl, Přemysl; Vlček, Jan; Bergmann, M.; Vondráček, Martin; Yatskiv, Roman; Bulíř, Jiří; Hubík, Pavel; Hruška, Petr; Drahokoupil, Jan; Abdellaoui, N.; Vrňata, M.; Lančok, Ján

2016-01-01

Roč. 122, č. 3 (2016), 1-8, č. článku 225. ISSN 0947-8396 R&D Projects: GA MŠk(CZ) LG15050; GA ČR(CZ) GAP108/11/0958; GA MŠk(CZ) LM2011029; GA ČR(CZ) GA14-10279S; GA MŠk(CZ) 7AMB14FR010 Institutional support: RVO:68378271 ; RVO:67985882 Keywords : samarium-doped zinc oxide zinc/phthalocyanine deposition * evaporation * pulsed laser deposition * thin films Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.455, year: 2016

Cross sections for d-{sup 3}H neutron interactions with samarium isotopes

Energy Technology Data Exchange (ETDEWEB)

Luo, Junhua; He, Long [Hexi Univ., Zhangye (China). School of Physics and Electromechanical Engineering; Wu, Chunlei; Jiang, Li [Chinese Academy of Engineering Physics, Mianyang (China). Inst. of Nuclear Physics and Chemistry

2016-11-01

The cross sections for (n,x) reactions on samarium isotopes were measured at (d-T) neutron energies of 13.5 and 14.8 MeV with the activation technique. Samples were activated along with Nb and Al monitor foils to determine the incident neutron flux. Theoretical calculations of excitation functions were performed using the nuclear model codes TALYS-1.6 and EMPIRE-3.2 Malta with default parameters, at neutron energies varying from the reaction threshold to 20 MeV. The results were discussed and compared with experimental data found in the literature. At neutron energies 13.5 and 14.8 MeV, the cross sections of the {sup 149}Sm(n,p){sup 149}Pm reaction are reported for the first time. The cross sections of the {sup 150}Sm(n,p){sup 150}Pm, {sup 144}Sm(n,p){sup 144}Pm, {sup 152}Sm(n,α){sup 149}Nd and {sup 144}Sm(n,α){sup 141}Nd reactions at different neutron energies reported in the present work can be added as new data in the nuclear databases.

Charge and transition densities of samarium isotopes in the interacting Boson model

International Nuclear Information System (INIS)

Moinester, M.A.; Alster, J.; Dieperink, A.E.L.

1982-01-01

The interacting boson approximation (IBA) model has been used to interpret the ground-state charge distributions and lowest 2 + transition charge densities of the even samarium isotopes for A = 144-154. Phenomenological boson transition densities associated with the nucleons comprising the s-and d-bosons of the IBA were determined via a least squares fit analysis of charge and transition densities in the Sm isotopes. The application of these boson trasition densities to higher excited 0 + and 2 + states of Sm, and to 0 + and 2 + transitions in neighboring nuclei, such as Nd and Gd, is described. IBA predictions for the transition densities of the three lowest 2 + levels of 154 Gd are given and compared to theoretical transition densities based on Hartree-Fock calculations. The deduced quadrupole boson transition densities are in fair agreement with densities derived previously from 150 Nd data. It is also shown how certain moments of the best fit boson transition densities can simply and sucessfully describe rms radii, isomer shifts, B(E2) strengths, and transition radii for the Sm isotopes. (orig.)

Thermodynamics of coproportionation reactions of homogeneous samarium (3) and yttrium (3) nitrates solvates with neutral organic phosphorus compounds

International Nuclear Information System (INIS)

Pyartman, A.K.

1995-01-01

Reaction heats of homogeneous samarium (3) and yttrium (3) nitrate solvates coproportionation with neutral organophosphoric compounds (tri-n.-butylphosphate, diisooctylmethylphosphonate, diisoamylmethylphosphonate) at T=298.15 K in hexane have been measured by thermochemical method. It has been ascertained that enthalpies of coproportionation reactions practically do not depend on the nature, concentration of rare earth metal (3) nitrate solvates in hexane, nature of neutral organophosphoric compound and constitute 1.1±-.2 kJ/mol. The Gibbs free energy of coproportionation reactions is -5.43 kJ/mol, while entropy of the reactions in 14.5±0.7 J/mol·K. 8 refs., 1 tab

Efficacy and toxicity of Samarium-153-EDTMP locally produced in the treatment of painful skeletal metastases

International Nuclear Information System (INIS)

Olea, E.; Quintana, J.C.; Nagel, J.; Arenas, L.; Tomicic, M.; Gil, M.C.; Araya, G.

2001-01-01

Samarium-153 emits medium-energy beta particles an a gamma photon with a physical half-life of 46,3 hours. When chelated to ethylenediaminetetramethylenephosphonic acid (EDTMP), it is remarkably stable in vitro and in vivo. In this study we administered randomly 0,5 and 1,0 mCi/Kg body weight (two groups), to 30 patients with painful metastatic bone cancer. Slight and spontaneously reversible myelotoxicity was observed. A bigger leukocyte and platelet suppression was obtained with 1,0 mCi/kg than 0,5 mCi/Kg dose. Pain palliation was obtained in 66% of the treated patients. Our preliminary results indicate that 153 Sm-EDTMP is a promising radiotherapeutic agent for palliative treatment of metastatic bone cancer pain where a reactor is available and at a very affordable cost. (author)

Determination of the nuclear electric charge distribution of samarium isotopes 144, 148, 150, 152, 154 by the muonic atom method

International Nuclear Information System (INIS)

Barreau, Pierre.

1977-01-01

The theory of the nucleus-negative muon system in the case of electrical interactions is discussed. The interactions of muons with the samarium isotopes 152, 154, 144, 148, 150 are investigated. After a description of the experimental device, from muon beam production to data acquisition (detection of the gamma spectra), the results are analyzed and the nuclear charge distribution parameters determined: for each isotope the absolute value of c (half-density radius) and t (skin thickness); for 152 Sm and 154 Sm the parameter β 2 (quadrupolar defomation). Nuclear polarization was accounted for throughout the analysis [fr

Pharmacokinetics of labelled compounds with technetium-99m and samarium-153

International Nuclear Information System (INIS)

Borda O, L.B.; Torres L, M.N.

1997-01-01

The purpose of this investigation was to establish the different pharmacokinetics parameters of the main radiopharmaceuticals labeled with technetium-99m and samarium-153. These parameters could be subsequently used as reference to compare other products with the same use. Mathematical models and a computerized pharmacokinetic program were used to this purpose. A biodistribution study in quadruplicate and/or quintuplicate was conducted for each radiopharmaceutical, data was was obtained in injection dose percentages. The biodistribution study involved the injection of a predetermined dose of the radiopharmaceutical into animals (rats or mice), which were subsequently put away at different time intervals, removing the relevant organs. Activity in each organ was read by means of a well-type NaI scintillation counter, data obtained in activity counts was transformed into injection dose percentages. Based on these percentages, the mathematical model was constructed and the pharmacokinetic parameters were obtained using the computerized program Expo 2 v. 1, which is written in C language and works in windows. Analyzing the results obtained, we can conclude that the use of the Expo 2 v. 1 program for a bi compartmental analysis allowed us to obtain reliable pharmacokinetic parameters which describe what happens in the organism when the radiopharmaceutical passes from the central compartment to the peripheral one and vice versa

Pyroelectric properties and electrical conductivity in samarium doped BiFeO 3 ceramics

KAUST Repository

Yao, Yingbang

2012-06-01

Samarium (Sm 3+) doped BiFeO 3 (BFO) ceramics were prepared by a modified solid-state-reaction method which adopted a rapid heating as well as cooling during the sintering process. The pyroelectric coefficient increased from 93 to 137 μC/m 2 K as the Sm 3+ doping level increased from 1 mol% to 8 mol%. Temperature dependence of the pyroelectric coefficient showed an abrupt decrease above 80 °C in all samples, which was associated with the increase of electrical conductivity with temperature. This electrical conduction was attributed to oxygen vacancy existing in the samples. An activation energy of ∼0.7 eV for the conduction process was found to be irrespective of the Sm 3+ doping level. On the other hand, the magnetic Néel temperature (T N) decreased with increasing Sm 3+ doping level. On the basis of our results, the effects of Sm doping level on the pyroelectric and electrical properties of the BFO were revealed. © 2011 Elsevier Ltd. All rights reserved.

Studies on the structural, optical and dielectric properties of samarium coordinated with salicylic acid single crystal

Science.gov (United States)

Singh, Harjinder; Slathia, Goldy; Gupta, Rashmi; Bamzai, K. K.

2018-04-01

Samarium coordinated with salicylic acid was successfully grown as a single crystal by low temperature solution technique using mixed solvent of methanol and water in equal ratio. Structural characterization was carried out by single crystal X-ray diffraction analysis and it crystallizes in centrosymmetric space group P121/c1. FTIR and UV-Vis-NIR spectroscopy confirmed the compound formation and help to determine the mode of binding of the ligand to the rare earth-metal ion. Dielectric constant and dielectric loss have been measured over the frequency range 100 Hz - 30MHz. The decrease in dielectric constant with increases in frequency is due to the transition from interfacial polarization to dipolar polarization. The small value of dielectric constant at higher frequency ensures that the crystal is good candidate for NLO devices. Dielectric loss represents the resistive nature of the material.

Quenching oscillating behaviors in fractional coupled Stuart-Landau oscillators

Science.gov (United States)

Sun, Zhongkui; Xiao, Rui; Yang, Xiaoli; Xu, Wei

2018-03-01

Oscillation quenching has been widely studied during the past several decades in fields ranging from natural sciences to engineering, but investigations have so far been restricted to oscillators with an integer-order derivative. Here, we report the first study of amplitude death (AD) in fractional coupled Stuart-Landau oscillators with partial and/or complete conjugate couplings to explore oscillation quenching patterns and dynamics. It has been found that the fractional-order derivative impacts the AD state crucially. The area of the AD state increases along with the decrease of the fractional-order derivative. Furthermore, by introducing and adjusting a limiting feedback factor in coupling links, the AD state can be well tamed in fractional coupled oscillators. Hence, it provides one an effective approach to analyze and control the oscillating behaviors in fractional coupled oscillators.

Detonation nanodiamond introduced into samarium doped ceria electrolyte improving performance of solid oxide fuel cell

Science.gov (United States)

Pei, Kai; Li, Hongdong; Zou, Guangtian; Yu, Richeng; Zhao, Haofei; Shen, Xi; Wang, Liying; Song, Yanpeng; Qiu, Dongchao

2017-02-01

A novel electrolyte materials of introducing detonation nanodiamond (DNDs) into samarium doped ceria (SDC) is reported here. 1%wt. DNDs doping SDC (named SDC/ND) can enlarge the electrotyle grain size and change the valence of partial ceria. DNDs provide the widen channel to accelerate the mobility of oxygen ions in electrolyte. Larger grain size means that oxygen ions move easier in electrolyte, it can also reduce the alternating current (AC) impedance spectra of internal grains. The lower valence of partial Ce provides more oxygen vacancies to enhance mobility rate of oxygen ions. Hence all of them enhance the transportation of oxygen ions in SDC/ND electrolyte and the OCV. Ultimately the power density of SOFC can reach 762 mw cm-2 at 800 °C (twice higher than pure SDC, which is 319 mw cm-2 at 800 °C), and it remains high power density in the intermediate temperature (600-800 °C). It is relatively high for the electrolyte supported (300 μm) cells.

Use of dispersive liquid-liquid microextraction for simultaneous preconcentration of samarium, europium, gadolinium and dysprosium

International Nuclear Information System (INIS)

Mallah, M.H.; Atomic Energy Organization of Iran, Tehran; Shemirani, F.; Ghannadi Maragheh, M.

2008-01-01

A new preconcentration method of dispersive liquid-liquid microextraction (DLLME) was developed for simultaneous preconcentration of samarium, europium, gadolinium and dysprosium. DLLME technique was successfully used as a sample preparation method. In this preconcentration method, an appropriate mixture of extraction solvent, disperser solvent was injected rapidly into an aqueous solution containing Sm, Eu, Gd and Dy after complex formation using chelating reagent of the 1-(2-pyridylazo)-2-naphthol (PAN). After phase separation, 0.5 mL of the settled phase containing enriched analytes was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The main factors affected the preconcentration of Sm, Eu, Gd and Dy were extraction and dispersive solvent type and their volume, extraction time, volume of chelating agent (PAN), centrifuge speed and drying temperature of the samples. Under the best operating condition simultaneous preconcentration factors of 80, 100, 103 and 78 were obtained for Sm, Eu, Gd and Dy, respectively. (author)

Oscillators and Eigenvalues

DEFF Research Database (Denmark)

Lindberg, Erik

1997-01-01

In order to obtain insight in the nature of nonlinear oscillators the eigenvalues of the linearized Jacobian of the differential equations describing the oscillator are found and displayed as functions of time. A number of oscillators are studied including Dewey's oscillator (piecewise linear wit...... with negative resistance), Kennedy's Colpitts-oscillator (with and without chaos) and a new 4'th order oscillator with hyper-chaos....

Characterization of luminescent samarium doped HfO2 coatings synthesized by spray pyrolysis technique

International Nuclear Information System (INIS)

Chacon-Roa, C; Guzman-Mendoza, J; Aguilar-Frutis, M; Garcia-Hipolito, M; Alvarez-Fragoso, O; Falcony, C

2008-01-01

Trivalent samarium (Sm 3+ ) doped hafnium oxide (HfO 2 ) films were deposited using the spray pyrolysis deposition technique. The films were deposited on Corning glass substrates at temperatures ranging from 300 to 550 deg. C using chlorides as raw materials. Films, mostly amorphous, were obtained when deposition temperatures were below 350 deg. C. However, for temperatures higher than 400 deg. C, the films became polycrystalline, presenting the HfO 2 monoclinic phase. Scanning electron microscopy of the films revealed a rough surface morphology with spherical particles. Also, electron energy dispersive analysis was performed on these films. The photoluminescence and cathodoluminescence characteristics of the HfO 2 : SmCl 3 films, measured at room temperature, exhibited four main bands centred at 570, 610, 652 and 716 nm, which are due to the well-known intra-4f transitions of the Sm 3+ ion. It was found that the overall emission intensity rose as the deposition temperature was increased. Furthermore, a concentration quenching of the luminescence intensity was also observed

The theoretical basis and clinical methodology for stereotactic interstitial brain tumor irradiation using iododeoxyuridine as a radiation sensitizer and samarium-145 as a brachytherapy source

International Nuclear Information System (INIS)

Goodman, J.H.; Gahbauer, R.A.; Kanellitsas, C.; Clendenon, N.R.; Laster, B.H.; Fairchild, R.G.

1989-01-01

High grade astrocytomas have proven resistant to all conventional therapy. A technique to produce radiation enhancement during interstitial brain tumor irradiation by using a radiation sensitizer (IdUrd) and by stimulation of Auger electron cascades through absorption of low energy photons in iodine (Photon activation) is described. Clinical studies using IdUrd, 192 Ir as a brachytherapy source, and external radiation have produced promising results. Substituting samarium-145 for 192 Ir in this protocol is expected to produce enhanced results. 15 refs

Enhancement of the fluorescence of the samarium (III) complex by gadolinium (III)

International Nuclear Information System (INIS)

Yun-Xiang, C.; Zhang-Hua, L.

1988-01-01

The increase in sensitivity and selectivity of reactions in which colored species are formed by the addition of different metal ions is an area of research that has recently been developed. This phenomenon, which is sometimes called cocolaration effect, has been explained by the formation of mixed metal complex. The authors found an analogous phenomenon of reactions forming fluorescent complexes. The complexes of Sm(III)-thenoyltrifluoroacetone (TTA)-phenanthroline (Phen)-Triton-X-100 (TX-100) and Gd(III) (or La(III), Lu(III) and Y(III))-TTA-Phen-TX-100 had practically no fluorescence separately. Instead, a fluorescence-enhancement phenomenon caused by adding Gd or La, Lu and Y ions to the system was observed for the first time. The intensity of the enhanced fluorescence of Sm(III) complex was increased in the following order: La< Y< Lu< Gd. By analogy with cocoloration effect, the authors call this new fluorescence-enhancement phenomenon the co-fluorescence effect. The object of this work was to study the enhancement effect of Gd(III) on the fluorescence of the Sm(III)-TTA-Phen-TX-100 system. The recommended fluorimetric method has been applied to the determination of trace amounts of samarium in ytterbium oxide with satisfactory results. A general reaction mechanism for the system studied was proposed

Time domain oscillating poles: Stability redefined in Memristor based Wien-oscillators

KAUST Repository

Talukdar, Abdul Hafiz Ibne

2012-07-28

Traditionally, the necessary and sufficient condition for any system to be oscillating is that its poles are located on the imaginary (jω) axis. In this paper, for the first time, we have shown that systems can oscillate with time-domain oscillating poles. The idea is verified using a Memristor based Wien oscillator. Sustained oscillations are observed without having the poles of the system fixed on the imaginary axis and the oscillating behavior of the system poles is reported. The oscillating resistance and triangular shape of FFT are also demonstrated with mathematical reasoning and simulation results to support the unusual and surprising characteristics. © 2009 IEEE.

Nature's Autonomous Oscillators

Science.gov (United States)

Mayr, H. G.; Yee, J.-H.; Mayr, M.; Schnetzler, R.

2012-01-01

Nonlinearity is required to produce autonomous oscillations without external time dependent source, and an example is the pendulum clock. The escapement mechanism of the clock imparts an impulse for each swing direction, which keeps the pendulum oscillating at the resonance frequency. Among nature's observed autonomous oscillators, examples are the quasi-biennial oscillation and bimonthly oscillation of the Earth atmosphere, and the 22-year solar oscillation. The oscillations have been simulated in numerical models without external time dependent source, and in Section 2 we summarize the results. Specifically, we shall discuss the nonlinearities that are involved in generating the oscillations, and the processes that produce the periodicities. In biology, insects have flight muscles, which function autonomously with wing frequencies that far exceed the animals' neural capacity; Stretch-activation of muscle contraction is the mechanism that produces the high frequency oscillation of insect flight, discussed in Section 3. The same mechanism is also invoked to explain the functioning of the cardiac muscle. In Section 4, we present a tutorial review of the cardio-vascular system, heart anatomy, and muscle cell physiology, leading up to Starling's Law of the Heart, which supports our notion that the human heart is also a nonlinear oscillator. In Section 5, we offer a broad perspective of the tenuous links between the fluid dynamical oscillators and the human heart physiology.

Oscillating heat pipes

CERN Document Server

Ma, Hongbin

2015-01-01

This book presents the fundamental fluid flow and heat transfer principles occurring in oscillating heat pipes and also provides updated developments and recent innovations in research and applications of heat pipes. Starting with fundamental presentation of heat pipes, the focus is on oscillating motions and its heat transfer enhancement in a two-phase heat transfer system. The book covers thermodynamic analysis, interfacial phenomenon, thin film evaporation,  theoretical models of oscillating motion and heat transfer of single phase and two-phase flows, primary  factors affecting oscillating motions and heat transfer,  neutron imaging study of oscillating motions in an oscillating heat pipes, and nanofluid’s effect on the heat transfer performance in oscillating heat pipes.  The importance of thermally-excited oscillating motion combined with phase change heat transfer to a wide variety of applications is emphasized. This book is an essential resource and learning tool for senior undergraduate, gradua...

Time domain oscillating poles: Stability redefined in Memristor based Wien-oscillators

KAUST Repository

Talukdar, Abdul Hafiz Ibne; Radwan, Ahmed G.; Salama, Khaled N.

2012-01-01

poles. The idea is verified using a Memristor based Wien oscillator. Sustained oscillations are observed without having the poles of the system fixed on the imaginary axis and the oscillating behavior of the system poles is reported. The oscillating

Results after therapy of pain from bone metastases with Samarium-153 in our centers in Lima, Peru

International Nuclear Information System (INIS)

Alvarado, N.; Eskenazi, S.; Valle, M.P.; Montoya, J.; Castro, M.; Montiel, L.; Velarde, V.; Jauregui, I.; Cueto, C.

2004-01-01

Full text: 105 patients with bone metastases from prostate and breast cancer; between 42 and 78 years age (median 61 years) were evaluated. Patients had intense pain that could not be managed with combinations of analgesic and anti tumoral drugs. All patients received 1.2 mCi/kg of Samarium-153 intravenously as treatment for pain due to bony metastases. The isotope obtained from atomic reactor placed in Lima - Peru, was provided by Peruvian Nuclear Energy Institute (IPEN). One week before therapy, all the patients had a bone scan study with Tc99m-MDP that showed the presence of multiple bone metastases with high blastic activity. Haematology and biochemical parameter checked were: Creatinine ( 150,000 mm3), Leukocytes (> 5,000 mm3), Red cells (>3,500,000 mm3). No problems were encountered during intravenous administration of the radioisotope. The side effects after treatment were: Primary effects: 16 cases of nausea, 2 of vomiting, 3 of headache, 28 had increment of pain, 6 had flushing. 50 patients did not have the primary symptoms. Secondary effects: 3 Patients showed drop in leukocyte count between 2nd and 3rd week of therapy. Red cells showed 10-15% decrease between 6th to 8th week. Platelets showed a decrease of about 15% with one peak between 1st and 2nd week post Samarium therapy. Data was analysed using an analogue visual scale of the pain with values from 0 - 10 (0-no pain; 10-maximum pain) and in the same way using the E.C.O.G. scale (Eastern Cooperative Oncology Group) in relationship with the Karnofsky index in order to establish functional recovery for each patient. The decrease of pain was seen between 4th-7th days (average 8 days). A second dose was given after 60 days in 12 patients and a third dose in 3 cases.11 patients died due to different causes between 30 - 60 days post treatment. The analgesic dose came down significantly in 80% of patients. We conclude that palliative therapy of metastatic bone pain in Peru is possible with radionuclides. It

One dimension harmonic oscillator

International Nuclear Information System (INIS)

Cohen-Tannoudji, Claude; Diu, Bernard; Laloe, Franck.

1977-01-01

The importance of harmonic oscillator in classical and quantum physics, eigenvalues and eigenstates of hamiltonian operator are discussed. In complement are presented: study of some physical examples of harmonic oscillators; study of stationnary states in the /x> representation; Hermite polynomials; resolution of eigenvalue equation of harmonic oscillator by polynomial method; isotope harmonic oscillator with three dimensions; charged harmonic oscillator in uniform electric field; quasi classical coherent states of harmonic oscillator; eigenmodes of vibration of two coupled harmonic oscillators; vibration modus of a continuous physical system (application to radiation: photons); vibration modus of indefinite linear chain of coupled harmonic oscillators (phonons); one-dimensional harmonic oscillator in thermodynamic equilibrium at temperature T [fr

Reactor oscillator - I - III, Part I; Reaktorski oscilator - I-III, I Deo

Energy Technology Data Exchange (ETDEWEB)

Lolic, B [Institute of Nuclear Sciences Boris Kidric, Laboratorija za fiziku reaktora, Vinca, Beograd (Serbia and Montenegro)

1961-12-15

Project 'Reactor oscillator' covers the following activities: designing reactor oscillators for reactors RA and RB with detailed engineering drawings; constructing and mounting of the oscillator; designing and constructing the appropriate electronic equipment for the oscillator; measurements at the RA and RB reactors needed for completing the oscillator construction.

On the effects of pressure and irradiation on the transport properties of samarium compounds with unstable valence

International Nuclear Information System (INIS)

Morillo, J.

1983-06-01

We present the first extensive study of electronic transport properties of ''quasi-stoichiometric'' SmS as a function of pressure P, temperature T, magnetic field B and defect concentration C. SmS which is a semiconductor, undergoes with increasing P a first order transition towards an homogeneous intermediate valence state. In the semiconducting phase (s.c.), the energie epsilon(f) necessary to delocalize a 4f electron increases greatly with T and is about 250meV at 300K. The phase diagram for the first order electronic transition Sm 2 + →Smsup(2+epsilon) with P has been determined for T 6 has been investigated by resistivity measurements under irradiation at 21K. The threshold energy Ed for displacement of Sm in SmS has been determined: Ed(Sm) = 20 +- 2 eV, and the observed effects of irradiation have been associated to samarium displacements (vacancies and interstitials) [fr

Effect of Zinc Oxide Doping on Electroluminescence and Electrical Behavior of Metalloporphyrins-Doped Samarium Complex

Science.gov (United States)

Janghouri, Mohammad; Amini, Mostafa M.

2018-02-01

Samarium complex [(Sm(III)] as a new host material was used for preparation of red organic light-emitting diodes (OLEDs). Devices with configurations of indium-doped tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):(poly(styrenesulfonate) (PEDOT:PSS (50 nm)/polyvinyl carbazole (PVK):[zinc oxide (ZnO)] (50 nm)/[(Sm(III)]:[zinc(II) 2,3-tetrakis(dihydroxyphenyl)-porphyrin and Pt(II) 2,3-dimethoxyporphyrin] (60 nm)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) (15 nm)/Al (150 nm) have been fabricated and investigated. An electroplex occurring at the (PVK/Sm: Pt(II) 2,3-dimethoxyporphyrin) interface has been suggested when ZnO nanoparticles were doped in PVK. OLED studies have revealed that the photophysical characteristics and electrical behavior of devices with ZnO nanoparticles are much better than those of devices with pure PVK. The efficiency of devices based on [(Sm(III)] was superior than that of known aluminum tris(8-hydroxyquinoline) (Alq3) and also our earlier reports on red OLEDs under the same conditions.

Oscillator monitor

International Nuclear Information System (INIS)

McNeill, G.A.

1981-01-01

Present high-speed data acquisition systems in nuclear diagnostics use high-frequency oscillators to provide timing references for signals recorded on fast, traveling-wave oscilloscopes. An oscillator's sinusoidal wave shape is superimposed on the recorded signal with each cycle representing a fixed time increment. During data analysis the sinusoid is stripped from the signal, leaving a clean signal shape with known timing. Since all signal/time relationships are totally dependant upon working oscillators, these critical devices must have remote verification of proper operation. This manual presents the newly-developed oscillator monitor which will provide the required verification

Solar Hydrogen Production via a Samarium Oxide-Based Thermochemical Water Splitting Cycle

Directory of Open Access Journals (Sweden)

Rahul Bhosale

2016-04-01

Full Text Available The computational thermodynamic analysis of a samarium oxide-based two-step solar thermochemical water splitting cycle is reported. The analysis is performed using HSC chemistry software and databases. The first (solar-based step drives the thermal reduction of Sm2O3 into Sm and O2. The second (non-solar step corresponds to the production of H2 via a water splitting reaction and the oxidation of Sm to Sm2O3. The equilibrium thermodynamic compositions related to the thermal reduction and water splitting steps are determined. The effect of oxygen partial pressure in the inert flushing gas on the thermal reduction temperature (TH is examined. An analysis based on the second law of thermodynamics is performed to determine the cycle efficiency (ηcycle and solar-to-fuel energy conversion efficiency (ηsolar−to−fuel attainable with and without heat recuperation. The results indicate that ηcycle and ηsolar−to−fuel both increase with decreasing TH, due to the reduction in oxygen partial pressure in the inert flushing gas. Furthermore, the recuperation of heat for the operation of the cycle significantly improves the solar reactor efficiency. For instance, in the case where TH = 2280 K, ηcycle = 24.4% and ηsolar−to−fuel = 29.5% (without heat recuperation, while ηcycle = 31.3% and ηsolar−to−fuel = 37.8% (with 40% heat recuperation.

Power oscillation damping controller

DEFF Research Database (Denmark)

2012-01-01

A power oscillation damping controller is provided for a power generation device such as a wind turbine device. The power oscillation damping controller receives an oscillation indicating signal indicative of a power oscillation in an electricity network and provides an oscillation damping control...

Biodistribution of samarium-153-EDTMP in rats treated with docetaxel Biodistribuição de EDTMP-153-samário em ratos tratados com docetaxel

Directory of Open Access Journals (Sweden)

Arthur Villarim Neto

2009-02-01

Full Text Available PURPOSE: Many patients with metastatic bone disease have to use radiopharmaceuticals associated with chemotherapy to relieve bone pain. The aim of this study was to assess the influence of docetaxel on the biodistribution of samarium-153-EDTMP in bones and other organs of rats. METHODS: Wistar male rats were randomly allocated into 2 groups of 6 rats each. The DS (docetaxel/samarium group received docetaxel (15 mg/kg intraperitoneally in two cycles 11 days apart. The S (samarium/control group rats were not treated with docetaxel. Nine days after chemotherapy, all the rats were injected with 0.1ml of samarium-153-EDTMP via orbital plexus (25µCi. After 2 hours, the animals were killed and samples of the brain, thyroid, lung, heart, stomach, colon, liver, kidney and both femurs were removed. The percentage radioactivity of each sample (% ATI/g was determined in an automatic gamma-counter (Wizard-1470, Perkin-Elmer, Finland. RESULTS: On the 9th day after the administration of the 2nd chemotherapy cycle, the rats had a significant weight loss (314.50±22.09g compared (pOBJETIVO: Muitos pacientes com metástases ósseas são tratados com radiofármacos associados com quimioterapia para alívio da dor óssea. O objetivo do trabalho foi estudar a influência do docetaxel na biodistribuição do EDTMP-153-samário nos ossos e outros órgãos de ratos. MÉTODOS: Ratos Wistar foram aleatoriamente alocados em 2 grupos de 6 animais cada. O grupo DS (docetaxel/samário recebeu docetaxel (15 mg/kg intraperitoneal em dois ciclos com 11 dias de intervalo. Os ratos do grupo S (samário/controle não foram tratados com docetaxel. Nove dias após a quimioterapia, todos os animais receberam 0,1ml de EDTMP-153-samário via plexo orbital (25µCi. Após 2 horas, os animais foram mortos e feitas biópsias de cérebro, tireóide, pulmão, coração, estômago, cólon, fígado, rim e fêmures. O percentual de radioatividade por grama (%ATI/g de tecido de cada bi

Oscillators - a simple introduction

DEFF Research Database (Denmark)

Lindberg, Erik

2013-01-01

Oscillators are kernel components of electrical and electronic circuits. Discussion of history, mechanisms and design based on Barkhausens observation. Discussion of a Wien Bridge oscillator based on the question: Why does this circuit oscillate ?......Oscillators are kernel components of electrical and electronic circuits. Discussion of history, mechanisms and design based on Barkhausens observation. Discussion of a Wien Bridge oscillator based on the question: Why does this circuit oscillate ?...

Restoration of oscillation in network of oscillators in presence of direct and indirect interactions

Energy Technology Data Exchange (ETDEWEB)

Majhi, Soumen; Bera, Bidesh K. [Physics and Applied Mathematics Unit, Indian Statistical Institute, Kolkata-700108 (India); Bhowmick, Sourav K. [Department of Electronics, Asutosh College, Kolkata-700026 (India); Ghosh, Dibakar, E-mail: diba.ghosh@gmail.com [Physics and Applied Mathematics Unit, Indian Statistical Institute, Kolkata-700108 (India)

2016-10-23

The suppression of oscillations in coupled systems may lead to several unwanted situations, which requires a suitable treatment to overcome the suppression. In this paper, we show that the environmental coupling in the presence of direct interaction, which can suppress oscillation even in a network of identical oscillators, can be modified by introducing a feedback factor in the coupling scheme in order to restore the oscillation. We inspect how the introduction of the feedback factor helps to resurrect oscillation from various kinds of death states. We numerically verify the resurrection of oscillations for two paradigmatic limit cycle systems, namely Landau–Stuart and Van der Pol oscillators and also in generic chaotic Lorenz oscillator. We also study the effect of parameter mismatch in the process of restoring oscillation for coupled oscillators. - Highlights: • Amplitude death is observed using direct and indirect coupling. • Revival of oscillation using feedback parameter is discussed. • Restoration of oscillation is observed in limit cycle and chaotic systems.

Oscillations of void lattices

International Nuclear Information System (INIS)

Akhiezer, A.I.; Davydov, L.N.; Spol'nik, Z.A.

1976-01-01

Oscillations of a nonideal crystal are studied, in which macroscopic defects (pores) form a hyperlattice. It is shown that alongside with acoustic and optical phonons (relative to the hyperlattice), in such a crystal oscillations of the third type are possible which are a hydridization of sound oscillations of atoms and surface oscillations of a pore. Oscillation spectra of all three types were obtained

Nonlinear Analysis of Ring Oscillator and Cross-Coupled Oscillator Circuits

KAUST Repository

Ge, Xiaoqing

2010-12-01

Hassan Khalil’s research results and beautifully written textbook on nonlinear systems have influenced generations of researchers, including the authors of this paper. Using nonlinear systems techniques, this paper analyzes ring oscillator and cross-coupled oscillator circuits, which are essential building blocks in digital systems. The paper first investigates local and global stability properties of an n-stage ring oscillator by making use of its cyclic structure. It next studies global stability properties of a class of cross-coupled oscillators which admit the representation of a dynamic system in feedback with a static nonlinearity, and presents su cient conditions for almost global convergence of the solutions to a limit cycle when the feedback gain is in the vicinity of a bifurcation point. The result are also extended to the synchronization of interconnected identical oscillator circuits.

Nonlinear Analysis of Ring Oscillator and Cross-Coupled Oscillator Circuits

KAUST Repository

Ge, Xiaoqing; Arcak, Murat; Salama, Khaled N.

2010-01-01

Hassan Khalil’s research results and beautifully written textbook on nonlinear systems have influenced generations of researchers, including the authors of this paper. Using nonlinear systems techniques, this paper analyzes ring oscillator and cross-coupled oscillator circuits, which are essential building blocks in digital systems. The paper first investigates local and global stability properties of an n-stage ring oscillator by making use of its cyclic structure. It next studies global stability properties of a class of cross-coupled oscillators which admit the representation of a dynamic system in feedback with a static nonlinearity, and presents su cient conditions for almost global convergence of the solutions to a limit cycle when the feedback gain is in the vicinity of a bifurcation point. The result are also extended to the synchronization of interconnected identical oscillator circuits.

Oscillations of disks

CERN Document Server

Kato, Shoji

2016-01-01

This book presents the current state of research on disk oscillation theory, focusing on relativistic disks and tidally deformed disks. Since the launch of the Rossi X-ray Timing Explorer (RXTE) in 1996, many high-frequency quasiperiodic oscillations (HFQPOs) have been observed in X-ray binaries. Subsequently, similar quasi-periodic oscillations have been found in such relativistic objects as microquasars, ultra-luminous X-ray sources, and galactic nuclei. One of the most promising explanations of their origin is based on oscillations in relativistic disks, and a new field called discoseismology is currently developing. After reviewing observational aspects, the book presents the basic characteristics of disk oscillations, especially focusing on those in relativistic disks. Relativistic disks are essentially different from Newtonian disks in terms of several basic characteristics of their disk oscillations, including the radial distributions of epicyclic frequencies. In order to understand the basic processes...

Self-oscillation in spin torque oscillator stabilized by field-like torque

International Nuclear Information System (INIS)

Taniguchi, Tomohiro; Tsunegi, Sumito; Kubota, Hitoshi; Imamura, Hiroshi

2014-01-01

The effect of the field-like torque on the self-oscillation of the magnetization in spin torque oscillator with a perpendicularly magnetized free layer was studied theoretically. A stable self-oscillation at zero field is excited for negative β while the magnetization dynamics stops for β = 0 or β > 0, where β is the ratio between the spin torque and the field-like torque. The reason why only the negative β induces the self-oscillation was explained from the view point of the energy balance between the spin torque and the damping. The oscillation power and frequency for various β were also studied by numerical simulation

Suppression and revival of oscillation in indirectly coupled limit cycle oscillators

International Nuclear Information System (INIS)

Sharma, P.R.; Kamal, N.K.; Verma, U.K.; Suresh, K.; Thamilmaran, K.; Shrimali, M.D.

2016-01-01

Highlights: • The phenomena of suppression and revival of oscillations are studied in indirectly coupled nonlinear oscillators. • The decay parameter and a feedback factor play a crucial role in emergent dynamical behavior of oscillators. • The critical curves for different dynamical regions are obtained analytically using linear stability analysis. • Electronic circuit experiments demonstrate these emergent dynamical states. - Abstract: We study the phenomena of suppression and revival of oscillations in a system of limit cycle oscillators coupled indirectly via a dynamic local environment. The dynamics of the environment is assumed to decay exponentially with time. We show that for appropriate coupling strength, the decay parameter of the environment plays a crucial role in the emergent dynamics such as amplitude death (AD) and oscillation death (OD). We also show that introducing a feedback factor in the diffusion term revives the oscillations in this system. The critical curves for the regions of different emergent states as a function of coupling strength, decay parameter of the environment and feedback factor in the coupling are obtained analytically using linear stability analysis. These results are found to be consistent with the numerics and are also observed experimentally.

Development and evaluation of copper-67 and samarium-153 labeled conjugates for tumor radioimmunotherapy

International Nuclear Information System (INIS)

Srivastava, S.C.; Mausner, L.F.; Mease, R.C.; Meinken, G.E.; Joshi, V.; Kolsky, K.; Sweet, M.; Steplewski, Z.

1995-01-01

The potential of utilizing receptor-specific agents such as monoclonal antibodies (MAb), and MAb-derived smaller molecules, as carriers of radionuclides for the selective destruction of tumors has stimulated much research activity. The success of such applications depends on many factors, especially the tumor binding properties of the antibody reagent, the efficiency of labeling and in-vivo stability of the radioconjugate and, on the careful choice of the radionuclide best suited to treat the tumor under consideration. The radiolabeled antibody technique for radioimmunotherapy (RIT), however, has experienced many limitations, and its success has not matched the expectations that were raised more than a decade ago. The problems that have been identified include: (i) degradation of antibody immunoreactivity resulting from chemical manipulations required for labeling; (ii) lack of suitable radioisotopes and methods for stable attachment of the radiolabel; (iii) in-vivo instability of the radioimmunoconjugates; (iv) excessive accumulation of activity in non-target locations; and (v) lack of radioimmunoconjugate accessibility to cells internal to a tumor mass. A careful choice of the radionuclide(s) best suited to treat the tumor under consideration is one of the most important requirements for successful radioimmunotherapy. This study evaluates copper 67 and samarium 153 for tumor radioimmunotherapy

The Oscillator Principle of Nature

DEFF Research Database (Denmark)

Lindberg, Erik

2012-01-01

Oscillators are found on all levels in Nature. The general oscillator concept is defined and investigated. Oscillators may synchronize into fractal patterns. Apparently oscillators are the basic principle in Nature. The concepts of zero and infinite are discussed. Electronic manmade oscillators...

Are the North Atlantic oscillation and the southern oscillation related in any time-scale?

Energy Technology Data Exchange (ETDEWEB)

Garcia, R.; Ribera, P.; Hernandez, E. [Universidad Complutense de Madrid (Spain). Facultad de Ciencias Fisicas; Gimenoo, L. [Fac. Ciencias, Univ. Vigo, Ourense (Spain)

2000-02-01

The north Atlantic oscillation (NAO) and the southern oscillation (SO) are compared from the standpoint of a possible common temporal scale of oscillation. To do this a cross-spectrum of the temporal series of NAO and SO indices was determined, finding a significant common oscillation of 6-8 years. To assure this finding, both series were decomposed in their main oscillations using singular spectrum analysis (SSA). Resulting reconstructed series of 6-8 years' oscillation were then cross-correlated without and with pre-whitened, the latter being significant. The main conclusion is a possible relationship between a common oscillation of 6-8 years that represents about 20% of the SO variance and about 25% of the NAO variance. (orig.)

Automatic Oscillating Turret.

Science.gov (United States)

1981-03-01

Final Report: February 1978 ZAUTOMATIC OSCILLATING TURRET SYSTEM September 1980 * 6. PERFORMING 01G. REPORT NUMBER .J7. AUTHOR(S) S. CONTRACT OR GRANT...o....e.... *24 APPENDIX P-4 OSCILLATING BUMPER TURRET ...................... 25 A. DESCRIPTION 1. Turret Controls ...Other criteria requirements were: 1. Turret controls inside cab. 2. Automatic oscillation with fixed elevation to range from 20* below the horizontal to

Inverted oscillator

Energy Technology Data Exchange (ETDEWEB)

Yuce, C [Physics Department, Anadolu University, Eskisehir (Turkey); Kilic, A [Physics Department, Anadolu University, Eskisehir (Turkey); Coruh, A [Physics Department, Sakarya University, Sakarya (Turkey)

2006-07-15

The inverted harmonic oscillator problem is investigated quantum mechanically. The exact wavefunction for the confined inverted oscillator is obtained and it is shown that the associated energy eigenvalues are discrete, and the energy is given as a linear function of the quantum number n.

Reactor oscillator - Proposal of the organisation for oscillator operation; Reaktorski oscilator - Predlog organizacije rada na oscilatoru

Energy Technology Data Exchange (ETDEWEB)

Lolic, B; Loloc, B [Institute of Nuclear Sciences Boris Kidric, Laboratorija za fiziku reaktora, Vinca, Beograd (Serbia and Montenegro)

1961-12-15

The organizational structure for operating the reactor with the reactor oscillator describes the duties of the reactor operators; staff responsible for operating the oscillator who are responsible for measurements, preparation of the samples and further treatment of the obtained results.

Experimental demonstration of revival of oscillations from death in coupled nonlinear oscillators

Energy Technology Data Exchange (ETDEWEB)

Senthilkumar, D. V., E-mail: skumarusnld@gmail.com [School of Physics, Indian Institute of Science Education and Research, Thiruvananthapuram 695016 (India); Centre for Nonlinear Science and Engineering, School of Electrical and Electronics Engineering, SASTRA University, Thanjavur 613 401 (India); Suresh, K. [Department of Physics, Anjalai Ammal-Engineering College, Kovilvenni 614 403, Tamilnadu (India); Centre for Nonlinear Dynamics, Bharathidasan University, Trichy 620024, Tamilnadu (India); Chandrasekar, V. K. [Centre for Nonlinear Science and Engineering, School of Electrical and Electronics Engineering, SASTRA University, Thanjavur 613 401 (India); Zou, Wei [School of Mathematics and Statistics, Huazhong University of Science and Technology, Wuhan 430074 (China); Centre for Mathematical Sciences, Huazhong University of Science and Technology, Wuhan 430074 (China); Dana, Syamal K. [CSIR-Indian Institute of Chemical Biology, Kolkata 700032 (India); Kathamuthu, Thamilmaran [Centre for Nonlinear Dynamics, Bharathidasan University, Trichy 620024, Tamilnadu (India); Kurths, Jürgen [Potsdam Institute for Climate Impact Research, Telegrafenberg, Potsdam D-14415 (Germany); Institute of Physics, Humboldt University Berlin, Berlin D-12489 (Germany); Institute for Complex Systems and Mathematical Biology, University of Aberdeen, Aberdeen AB24 3FX (United Kingdom); Department of Control Theory, Nizhny Novgorod State University, Gagarin Avenue 23, 606950 Nizhny Novgorod (Russian Federation)

2016-04-15

We experimentally demonstrate that a processing delay, a finite response time, in the coupling can revoke the stability of the stable steady states, thereby facilitating the revival of oscillations in the same parameter space where the coupled oscillators suffered the quenching of oscillation. This phenomenon of reviving of oscillations is demonstrated using two different prototype electronic circuits. Further, the analytical critical curves corroborate that the spread of the parameter space with stable steady state is diminished continuously by increasing the processing delay. Finally, the death state is completely wiped off above a threshold value by switching the stability of the stable steady state to retrieve sustained oscillations in the same parameter space. The underlying dynamical mechanism responsible for the decrease in the spread of the stable steady states and the eventual reviving of oscillation as a function of the processing delay is explained using analytical results.

Chromospheric oscillations

NARCIS (Netherlands)

Lites, B.W.; Rutten, R.J.; Thomas, J.H.

1995-01-01

We show results from SO/Sacramento Peak data to discuss three issues: (i)--the spatial occurrence of chromospheric 3--min oscillations; (ii)--the validity of Ca II H&K line-center Doppler Shift measurements; (iii)--the signi ?cance of oscillation power and phase at frequencies above 10 mHz.

Nonstationary oscillation of gyrotron backward wave oscillators with cylindrical interaction structure

International Nuclear Information System (INIS)

Chen, Shih-Hung; Chen, Liu

2013-01-01

The nonstationary oscillation of the gyrotron backward wave oscillator (gyro-BWO) with cylindrical interaction structure was studied utilizing both steady-state analyses and time-dependent simulations. Comparisons of the numerical results reveal that the gyro-BWO becomes nonstationary when the trailing field structure completely forms due to the dephasing energetic electrons. The backward propagation of radiated waves with a lower resonant frequency from the trailing field structure interferes with the main internal feedback loop, thereby inducing the nonstationary oscillation of the gyro-BWO. The nonstationary gyro-BWO exhibits the same spectral pattern of modulated oscillations with a constant frequency separation between the central frequency and sidebands throughout the whole system. The frequency separation is found to be scaled with the square root of the maximum field amplitude, thus further demonstrating that the nonstationary oscillation of the gyro-BWO is associated with the beam-wave resonance detuning

Oscillation Baselining and Analysis Tool

Energy Technology Data Exchange (ETDEWEB)

2017-03-27

PNNL developed a new tool for oscillation analysis and baselining. This tool has been developed under a new DOE Grid Modernization Laboratory Consortium (GMLC) Project (GM0072 - “Suite of open-source applications and models for advanced synchrophasor analysis”) and it is based on the open platform for PMU analysis. The Oscillation Baselining and Analysis Tool (OBAT) performs the oscillation analysis and identifies modes of oscillations (frequency, damping, energy, and shape). The tool also does oscillation event baselining (fining correlation between oscillations characteristics and system operating conditions).

Neutrino oscillations in matter

International Nuclear Information System (INIS)

Mikheyev, S.P.; Smirnov, A.Yu.

1986-01-01

In this paper we describe united formalism of ν-oscillations for different regimes, which is immediate generalization of vacuum oscillations theory. Adequate graphical representation of this formalism is given. We summarize main properties of ν-oscillations for different density distributions. (orig./BBOE)

Study of samarium modified lead zirconate titanate and nickel zinc ferrite composite system

Energy Technology Data Exchange (ETDEWEB)

Rani, Rekha [Department of Physics, SD PG College, Panipat 132103 (India); School of Physics and Materials Science, Thapar University, Patiala 147004 (India); Juneja, J.K., E-mail: jk_juneja@yahoo.com [Department of Physics, Hindu College, Sonepat 131001 (India); Singh, Sangeeta [Department of Physics, GVM Girls College, Sonepat 131001 (India); Raina, K.K. [School of Physics and Materials Science, Thapar University, Patiala 147004 (India); Prakash, Chandra [Solid State Physics Laboratory, Timarpur, Delhi 110054 (India)

2015-03-15

In the present work, composites of samarium substituted lead zirconate titanate and nickel zinc ferrite with compositional formula 0.95Pb{sub 1−3x/2} Sm{sub x}Zr{sub 0.65}Ti{sub 0.35}O{sub 3}–0.05Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} (x=0, 0.01, 0.02 and 0.03) were prepared by the conventional solid state route. X-ray diffraction analysis was carried out to confirm the coexistence of individual phases. Microstructural study was done by using scanning electron microscope. Dielectric constant and loss were studied as a function of temperature and frequency. To study ferroelectric and magnetic properties of the composite samples, corresponding P–E and M–H hysteresis loops were recorded. Change in magnetic properties of electrically poled composite sample (x=0.02) was studied to confirm the magnetoelectric (ME) coupling. ME coefficient (dE/dH) of the samples (x=0 and 0.02) was measured as a function of DC magnetic field. - Highlights: • We are reporting the effect of Sm substitution on PZT–NiZn ferrite composites. • Observation of both P–E and M–H loops confirms ferroelectric and magnetic ordering. • With Sm substitution, significant improvement in properties was observed. • Increase in magnetization for electrically poled sample is evidence of ME coupling. • Electric polarization is generated by applying magnetic field.

The colpitts oscillator family

DEFF Research Database (Denmark)

Lindberg, Erik; Murali, K.; Tamasevicius, A.

A tutorial study of the Colpitts oscillator family defined as all oscillators based on a nonlinear amplifier and a three- terminal linear resonance circuit with one coil and two capacitors. The original patents are investigated. The eigenvalues of the linearized Jacobian for oscillators based...

Retention capacity of samarium (III) in zircon for it possible use in retaining walls for confinement of nuclear residues; Capacidad de retencion de samario (III) en circon para su posible uso en barreras de contencion para confinamiento de residuos nucleares

Energy Technology Data Exchange (ETDEWEB)

Garcia G, N

2006-07-01

Mexico, as country that produces part of its electric power by nuclear means, should put special emphasis in the development of technologies guided to the sure and long term confinement of the high level nuclear residuals. This work studies the capacity that has the natural zircon to retain to the samarium (III) in solution, by what due, firstly, to characterize the zircon for technical instrumental to determine the purity and characteristic of the mineral in study. The instrumental techniques that were used to carry out the physicochemical characterization were the neutron activation analysis (NAA), the infrared spectroscopy (IS), the thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), semiquantitative analysis, dispersive energy spectroscopy (EDS), X-ray diffraction (XRD) and luminescence technique. The characterization of the surface properties carries out by means of the determination of the surface area using the BET multipoint technique, acidity constants, hydration time, the determination of the point of null charge (pH{sub PCN}) and density of surface sites (D{sub s}). The luminescence techniques were useful to determine the optimal point hydration of the zircon and for the quantification of the samarium, for that here intends the development of both analysis techniques. With the adjustment of the titration curves in the FITEQL 4 package the constants of surface acidity in the solid/liquid interface were determined. To the finish of this study it was corroborated that the zircon is a mineral that presents appropriate characteristics to be proposed as a contention barrier for the deep geologic confinement. With regard to the study of adsorption that one carries out the samarium retention it is superior to 90% under the described conditions. This investigation could also be applicable in the confinement of dangerous industrial residuals. (Author)

Bounded-oscillation Pushdown Automata

Directory of Open Access Journals (Sweden)

Pierre Ganty

2016-09-01

Full Text Available We present an underapproximation for context-free languages by filtering out runs of the underlying pushdown automaton depending on how the stack height evolves over time. In particular, we assign to each run a number quantifying the oscillating behavior of the stack along the run. We study languages accepted by pushdown automata restricted to k-oscillating runs. We relate oscillation on pushdown automata with a counterpart restriction on context-free grammars. We also provide a way to filter all but the k-oscillating runs from a given PDA by annotating stack symbols with information about the oscillation. Finally, we study closure properties of the defined class of languages and the complexity of the k-emptiness problem asking, given a pushdown automaton P and k >= 0, whether P has a k-oscillating run. We show that, when k is not part of the input, the k-emptiness problem is NLOGSPACE-complete.

Ferrites Ni{sub 0,5}Zn{sub 0,5}Fe{sub 2}O{sub 4} doped with samarium: structural analysis, morphological and electromagnetic; Ferritas Ni{sub 0,5}Zn{sub 0,5}Fe{sub 2}O{sub 4} dopada com samario: analise estrutural, morfologica e eletromagnetica

Energy Technology Data Exchange (ETDEWEB)

Costa, A.C.F.M.; Diniz, A.P., E-mail: anacristina@dema.ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academinca de Engenharia de Materiais; Viana, K.M.S. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, PE (Brazil). Escola de Ciencias e Tecnologia; Cornejo, D.R. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica; Kiminami, R.H.G.A. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Engenharia de Materiais

2010-07-01

This paper proposes to investigate the sintering at 1200 deg C/2h of Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2-x}Sm{sub x}O{sub 4} ferrite doped with 0.05; 0.075 e 0.1 mol of Sm synthesized by combustion reaction to evaluate the performance materials as absorbers of electromagnetic radiation. The influence of the concentration of samarium on the structure, morphology and electromagnetic properties of ferrites was studied. The resulting samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), magnetic measurements and reflectivity measurements in the frequency range between 8-12 GHz. The results showed that increasing the concentration of samarium caused a decrease in particle size of the samples, encouraging, therefore, to obtain materials with better values of magnetization and reflectivity, allowing for use as absorbers in narrow-band frequency between 9-10 GHz. (author)

Magnetically Coupled Magnet-Spring Oscillators

Science.gov (United States)

Donoso, G.; Ladera, C. L.; Martin, P.

2010-01-01

A system of two magnets hung from two vertical springs and oscillating in the hollows of a pair of coils connected in series is a new, interesting and useful example of coupled oscillators. The electromagnetically coupled oscillations of these oscillators are experimentally and theoretically studied. Its coupling is electromagnetic instead of…

Effects of increasing doses of samarium-153-ethylenediaminetetramethylene phosphonate on axial and appendicular skeletal growth in juvenile rabbits

International Nuclear Information System (INIS)

Essman, Stephanie C.; Lewis, Michael R.; Fox, Derek B.

2008-01-01

Introduction: Targeted radiotherapy using samarium-153-ethylenediaminetetramethylene phosphonate ( 153 Sm-EDTMP) is currently under investigation for treatment of osteosarcoma. Osteosarcoma often occurs in children, and previous studies on a juvenile rabbit model demonstrated that clinically significant damage to developing physeal cartilage may occur as a result of systemic 153 Sm-EDTMP therapy. The aim of this study was to evaluate the late effects of 153 Sm-EDTMP on skeletal structures during growth to maturity and to determine if there is a dose response of 153 Sm-EDTMP on growth of long bones. Methods: Female 8-week-old New Zealand white rabbits were divided into three treatment groups plus controls. Each rabbit was intravenously administered a predetermined dose of 153 Sm-EDTMP. Multiple bones of each rabbit were radiographed every 2 months until physeal closure, with subsequent measurements made to assess for abbreviated bone growth. Statistical analyses were performed to determine the differences in bone length between groups, with significance set at P 153 Sm-EDTMP. Further investigation regarding the effects of bone-seeking radiopharmaceuticals on bone growth and physeal cartilage is warranted

Memristor-based reactance-less oscillator

KAUST Repository

Zidan, Mohammed A.; Omran, Hesham; Radwan, Ahmed G.; Salama, Khaled N.

2012-01-01

The first reactance-less oscillator is introduced. By using a memristor, the oscillator can be fully implemented on-chip without the need for any capacitors or inductors, which results in an area-efficient fully integrated solution. The concept of operation of the proposed oscillator is explained and detailed mathematical analysis is introduced. Closed-form expressions for the oscillation frequency and oscillation conditions are derived. Finally, the derived equations are verified with circuit simulations showing excellent agreement. © 2011 The Institution of Engineering and Technology.

Memristor-based reactance-less oscillator

KAUST Repository

Zidan, Mohammed A.

2012-10-02

The first reactance-less oscillator is introduced. By using a memristor, the oscillator can be fully implemented on-chip without the need for any capacitors or inductors, which results in an area-efficient fully integrated solution. The concept of operation of the proposed oscillator is explained and detailed mathematical analysis is introduced. Closed-form expressions for the oscillation frequency and oscillation conditions are derived. Finally, the derived equations are verified with circuit simulations showing excellent agreement. © 2011 The Institution of Engineering and Technology.

A theory of generalized Bloch oscillations

International Nuclear Information System (INIS)

Duggen, Lars; Lassen, Benny; Lew Yan Voon, L C; Willatzen, Morten

2016-01-01

Bloch oscillations of electrons are shown to occur for cases when the energy spectrum does not consist of the traditional evenly-spaced ladders and the potential gradient does not result from an external electric field. A theory of such generalized Bloch oscillations is presented and an exact calculation is given to confirm this phenomenon. Our results allow for a greater freedom of design for experimentally observing Bloch oscillations. For strongly coupled oscillator systems displaying Bloch oscillations, it is further demonstrated that reordering of oscillators leads to destruction of Bloch oscillations. We stipulate that the presented theory of generalized Bloch oscillations can be extended to other systems such as acoustics and photonics. (paper)

Reactor oscillator - I - III, Part I

International Nuclear Information System (INIS)

Lolic, B.

1961-12-01

Project 'Reactor oscillator' covers the following activities: designing reactor oscillators for reactors RA and RB with detailed engineering drawings; constructing and mounting of the oscillator; designing and constructing the appropriate electronic equipment for the oscillator; measurements at the RA and RB reactors needed for completing the oscillator construction

Neutrino Oscillation Physics

International Nuclear Information System (INIS)

Kayser, Boris

2014-01-01

To complement the neutrino-physics lectures given at the 2011 International School on Astro Particle Physics devoted to Neutrino Physics and Astrophysics (ISAPP 2011; Varenna, Italy), at the 2011 European School of High Energy Physics (ESHEP 2011; Cheila Gradistei, Romania), and, in modified form, at other summer schools, we present here a written description of the physics of neutrino oscillation. This description is centered on a new way of deriving the oscillation probability. We also provide a brief guide to references relevant to topics other than neutrino oscillation that were covered in the lectures

Oscillator, neutron modulator

International Nuclear Information System (INIS)

Agaisse, R.; Leguen, R.; Ombredane, D.

1960-01-01

The authors present a mechanical device and an electronic control circuit which have been designed to sinusoidally modulate the reactivity of the Proserpine atomic pile. The mechanical device comprises an oscillator and a mechanism assembly. The oscillator is made of cadmium blades which generate the reactivity oscillation. The mechanism assembly comprises a pulse generator for cycle splitting, a gearbox and an engine. The electronic device comprises or performs pulse detection, an on-off device, cycle pulse shaping, phase separation, a dephasing amplifier, electronic switches, counting scales, and control devices. All these elements are briefly presented

Neutrino Oscillation Physics

Energy Technology Data Exchange (ETDEWEB)

Kayser, Boris [Fermilab (United States)

2014-07-01

To complement the neutrino-physics lectures given at the 2011 International School on Astro Particle Physics devoted to Neutrino Physics and Astrophysics (ISAPP 2011; Varenna, Italy), at the 2011 European School of High Energy Physics (ESHEP 2011; Cheila Gradistei, Romania), and, in modified form, at other summer schools, we present here a written description of the physics of neutrino oscillation. This description is centered on a new way of deriving the oscillation probability. We also provide a brief guide to references relevant to topics other than neutrino oscillation that were covered in the lectures.

OSCILLATING FILAMENTS. I. OSCILLATION AND GEOMETRICAL FRAGMENTATION

Energy Technology Data Exchange (ETDEWEB)

Gritschneder, Matthias; Heigl, Stefan; Burkert, Andreas, E-mail: gritschm@usm.uni-muenchen.de [University Observatory Munich, LMU Munich, Scheinerstrasse 1, D-81679 Munich (Germany)

2017-01-10

We study the stability of filaments in equilibrium between gravity and internal as well as external pressure using the grid-based AMR code RAMSES. A homogeneous, straight cylinder below a critical line mass is marginally stable. However, if the cylinder is bent, such as with a slight sinusoidal perturbation, an otherwise stable configuration starts to oscillate, is triggered into fragmentation, and collapses. This previously unstudied behavior allows a filament to fragment at any given scale, as long as it has slight bends. We call this process “geometrical fragmentation.” In our realization, the spacing between the cores matches the wavelength of the sinusoidal perturbation, whereas up to now, filaments were thought to be only fragmenting on the characteristic scale set by the mass-to-line ratio. Using first principles, we derive the oscillation period as well as the collapse timescale analytically. To enable a direct comparison with observations, we study the line-of-sight velocity for different inclinations. We show that the overall oscillation pattern can hide the infall signature of cores.

Free oscillation of the Earth

Directory of Open Access Journals (Sweden)

Y. Abedini

2000-06-01

Full Text Available   This work is a study of the Earths free oscillations considering a merge of solid and liquid model. At the turn of 19th century Geophysicists presented the theory of the free oscillations for a self-gravitating, isotropic and compressible sphere. Assuming a steel structure for an Earth size sphere, they predicted a period of oscillation of about 1 hour. About 50 years later, the free oscillations of stars was studied by Cowling and others. They classified the oscillation modes of the stars into acoustic and gravity modes on the basis of their driving forces. These are pressure and buoyancy forces respectively. The earliest measurements for the period of the free oscillations of the Earth was made by Benyove from a study of Kamchathca earthquake. Since then, the Geophysicists have been trying to provide a theoretical basis for these measurements. Recently, the theory concerning oscillations of celestial fluids is extended by Sobouti to include the possible oscillations of the Earthlike bodies. Using the same technique, we study the free oscillations of a spherically symmetric, non-rotating and elastic model for the Earth.   We used the actual data of the Earths interior structure in our numerical calculations. Numerical results show that there exist three distinct oscillation modes namely acoustic, gravity and toroidal modes. These modes are driven by pressure, buoyancy and shear forces respectively. The shear force is due to the elastic properties of the solid part of the Earth. Our numerical results are consistent with the seismic data recorded from earthquake measurements.

Driven, autoresonant three-oscillator interactions

International Nuclear Information System (INIS)

Yaakobi, O.; Friedland, L.; Henis, Z.

2007-01-01

An efficient control scheme of resonant three-oscillator interactions using an external chirped frequency drive is suggested. The approach is based on formation of a double phase-locked (autoresonant) state in the system, as the driving oscillation passes linear resonance with one of the interacting oscillators. When doubly phase locked, the amplitudes of the oscillators increase with time in proportion to the driving frequency deviation from the linear resonance. The stability of this phase-locked state and the effects of dissipation and of the initial three-oscillator frequency mismatch on the autoresonance are analyzed. The associated autoresonance threshold phenomenon in the driving amplitude is also discussed. In contrast to other nonlinear systems, driven, autoresonant three-oscillator excitations are independent of the sign of the driving frequency chirp rate

Self-Synchronized Phenomena Generated in Rotor-Type Oscillators: On the Influence of Coupling Condition between Oscillators

Science.gov (United States)

Bonkobara, Yasuhiro; Mori, Hiroki; Kondou, Takahiro; Ayabe, Takashi

Self-synchronized phenomena generated in rotor-type oscillators mounted on a straight-line spring-mass system are investigated experimentally and analytically. In the present study, we examine the occurrence region and pattern of self-synchronization in two types of coupled oscillators: rigidly coupled oscillators and elastically coupled oscillators. It is clarified that the existence regions of stable solutions are governed mainly by the linear natural frequency of each spring-mass system. The results of numerical analysis confirm that the self-synchronized solutions of the elastically coupled oscillators correspond to those of the rigidly coupled oscillators. In addition, the results obtained in the present study are compared with the previously reported results for a metronome system and a moving apparatus and the different properties of the phenomena generated in the rotor-type oscillators and the pendulum-type oscillators are shown in terms of the construction of branches of self-synchronized solution and the stability.

Observation of near infrared and enhanced visible emissions from electroluminescent devices with organo samarium(III) complex

Energy Technology Data Exchange (ETDEWEB)

Chu, B [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Li, W L [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Hong, Z R [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Zang, F X [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Wei, H Z [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Wang, D Y [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Li, M T [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Lee, C S [Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China); Lee, S T [Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China)

2006-11-07

Samarium (dibenzoylmethanato){sub 3} bathophenanthroline (Sm(DBM){sub 3} bath) was employed as an emitting and electron transport layer in organic light emitting diodes (OLEDs), and narrow electroluminescent (EL) emissions of a Sm{sup 3+} ion were observed in the visible and near infrared (NIR) region, differing from those of the same devices with Eu{sup 3+}- or Tb{sup 3+}-complex EL devices with the same structure. The EL emissions of the Sm{sup 3+}-devices originate from transitions from {sup 4}G{sub 5/2} to the lower respective levels of Sm{sup 3+} ions. A maximum luminance of 490 cd m{sup -2} at 15 V and an EL efficiency of 0.6% at 0.17 mA cm{sup -2} were obtained in the visible region, and the improved efficiency should be attributed to introducing a transitional layer between the N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-diphenyl-4,4'-diamine (TPD) film and the Sm(DBM){sub 3} bath film and the avoidance of interfacial exciplex emission in devices. Sharp emissions of Sm{sup 3+} ions in the NIR region were also observed under a lower threshold value less than 4.5 V.

Zero-point oscillations, zero-point fluctuations, and fluctuations of zero-point oscillations

International Nuclear Information System (INIS)

Khalili, Farit Ya

2003-01-01

Several physical effects and methodological issues relating to the ground state of an oscillator are considered. Even in the simplest case of an ideal lossless harmonic oscillator, its ground state exhibits properties that are unusual from the classical point of view. In particular, the mean value of the product of two non-negative observables, kinetic and potential energies, is negative in the ground state. It is shown that semiclassical and rigorous quantum approaches yield substantially different results for the ground state energy fluctuations of an oscillator with finite losses. The dependence of zero-point fluctuations on the boundary conditions is considered. Using this dependence, it is possible to transmit information without emitting electromagnetic quanta. Fluctuations of electromagnetic pressure of zero-point oscillations are analyzed, and the corresponding mechanical friction is considered. This friction can be viewed as the most fundamental mechanism limiting the quality factor of mechanical oscillators. Observation of these effects exceeds the possibilities of contemporary experimental physics but almost undoubtedly will be possible in the near future. (methodological notes)

Brain Oscillations, Hypnosis, and Hypnotizability.

Science.gov (United States)

Jensen, Mark P; Adachi, Tomonori; Hakimian, Shahin

2015-01-01

This article summarizes the state-of-science knowledge regarding the associations between hypnosis and brain oscillations. Brain oscillations represent the combined electrical activity of neuronal assemblies, usually measured as specific frequencies representing slower (delta, theta, alpha) and faster (beta, gamma) oscillations. Hypnosis has been most closely linked to power in the theta band and changes in gamma activity. These oscillations are thought to play a critical role in both the recording and recall of declarative memory and emotional limbic circuits. The authors propose that this role may be the mechanistic link between theta (and perhaps gamma) oscillations and hypnosis, specifically, that the increases in theta oscillations and changes in gamma activity observed with hypnosis may underlie some hypnotic responses. If these hypotheses are supported, they have important implications for both understanding the effects of hypnosis and for enhancing response to hypnotic treatments.

Synthesis and characterization of samarium-doped ZnS nanoparticles: A novel visible light responsive photocatalyst

Energy Technology Data Exchange (ETDEWEB)

Hanifehpour, Younes, E-mail: y_hanifehpour@yu.ac.kr [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Soltani, Behzad; Amani-Ghadim, Ali Reza; Hedayati, Behnam [Department of Chemistry, Faculty of Basic Sciences, Azarbaijan Shahid Madani University, Tabriz (Iran, Islamic Republic of); Khomami, Bamin [Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Joo, Sang Woo, E-mail: swjoo1@gmail.com [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of)

2016-04-15

Highlights: • Sm-doped ZnS Nanomaterials were synthesized by hydrothermal method. • The as-prepared compounds were characterized by XRD, TEM, XPS, SEM and UV techniques. • The photocatalytic effect of compounds was determined by Reactive Red 43 degradation. • The degradation of RRed 43 followed the Langmuir–Hinshelwood kinetic model. - Abstract: We prepared pure and samarium-doped ZnS (Sm{sub x}Zn{sub 1−x}S{sub 1+0.5x}) nanoparticles via hydrothermal process at 160 °C for 24 h. XRD analysis shows that the particles were well crystallized and corresponds to a cubic sphalerite phase. SEM and TEM images indicate that the sizes of the particles were in the range of 20–60 nm. The photocatalytic activity of Sm-doped ZnS nanoparticles was evaluated by monitoring the decolorization of Reactive Red 43 in aqueous solution under visible light irradiation. The color removal efficiency of Sm{sub 0.04}Zn{sub 0.96}S and pure ZnS was 95.1% and 28.7% after 120 min of treatment, respectively. Among the different amounts of dopant agent used, 4% Sm-doped ZnS nanoparticles indicated the highest decolorization. We found that the presence of inorganic ions such as Cl{sup −}, CO{sub 3}{sup 2−} and other radical scavengers such as buthanol and isopropyl alcohol reduced the decolorization efficiency.

Single ICCII Sinusoidal Oscillators Employing Grounded Capacitors

Directory of Open Access Journals (Sweden)

J. W. Horng

2011-09-01

Full Text Available Two inverting second-generation current conveyors (ICCII based sinusoidal oscillators are presented. The first sinusoidal oscillator is composed of one ICCII, two grounded capacitors and two resistors. The oscillation condition and oscillation frequency can be orthogonally controllable. The second sinusoidal oscillator is composed of one ICCII, two grounded capacitors and three resistors. The oscillation condition and oscillation frequency can be independently controllable through different resistors.

The study on pressure oscillation and heat transfer characteristics of oscillating capillary tube heat pipe

International Nuclear Information System (INIS)

Kim, Jong Soo; Bui, Ngoc Hung; Jung, Hyun Seok; Lee, Wook Hyun

2003-01-01

In the present study, the characteristics of pressure oscillation and heat transfer performance in an oscillating capillary tube heat pipe were experimentally investigated with respect to the heat flux, the charging ratio of working fluid, and the inclination angle to the horizontal orientation. The experimental results showed that the frequency of pressure oscillation was between 0.1 Hz and 1.5 Hz at the charging ratio of 40 vol.%. The saturation pressure of working fluid in the oscillating capillary tube heat pipe increased as the heat flux was increased. Also, as the charging ratio of working fluid was increased, the amplitude of pressure oscillation increased. When the pressure waves were symmetric sinusoidal waves at the charging ratios of 40 vol.% and 60 vol.%, the heat transfer performance was improved. At the charging ratios of 20 vol.% and 80 vol.%, the waveforms of pressure oscillation were more complicated, and the heat transfer performance reduced. At the charging ratio of 40 vol.%, the heat transfer performance of the OCHP was at the best when the inclination angle was 90 .deg., the pressure wave was a sinusoidal waveform, the pressure difference was at the least, the oscillation amplitude was at the least, and the frequency of pressure oscillation was the highest

Bimodal oscillations in nephron autoregulation

DEFF Research Database (Denmark)

Sosnovtseva, Olga; Pavlov, A.N.; Mosekilde, Erik

2002-01-01

The individual functional unit of the kidney (the nephron) displays oscillations in its pressure and flow regulation at two different time scales: fast oscillations associated with a myogenic dynamics of the afferent arteriole, and slower oscillations arising from a delay in the tubuloglomerular ...

Study for the determination of samarium, europium,terbium, dysprosium and yttrium in gadolinium oxide matrix by means of atomic absorption spectrophotometry using a graphite furnace

International Nuclear Information System (INIS)

Caires, A.C.F.

1985-01-01

A study for determination of samarium, europium, terbium, dysprosium and yttrium in a gadolinium oxide matrix by atomic absorption spectrophotometry using a graphite furnace is presented. The best charrring and atomization conditions were estabilished for each element, the most convenient ressonance lines being selected as well. The study was carried out for the mentioned lanthanides both when pure and when in binary mixtures with gadolinium, besides those where all for them were together with gadolinium. The determination limits for pure lanthanides were found to be between 1.3 and 9.6 ng assuming a 20% relative standard deviation as acceptable. The detection limits were in the range 0.51 and 7.5 ng, assuming as positive any answer higher than twofold the standard deviation. (author) [pt

Case for neutrino oscillations

International Nuclear Information System (INIS)

Ramond, P.

1982-01-01

The building of a machine capable of producing an intense, well-calibrated beam of muon neutrinos is regarded by particle physicists with keen interest because of its ability of studying neutrino oscillations. The possibility of neutrino oscillations has long been recognized, but it was not made necessary on theoretical or experimental grounds; one knew that oscillations could be avoided if neutrinos were massless, and this was easily done by the conservation of lepton number. The idea of grand unification has led physicists to question the existence (at higher energies) of global conservation laws. The prime examples are baryon-number conservation, which prevents proton decay, and lepton-number conservation, which keeps neutrinos massless, and therefore free of oscillations. The detection of proton decay and neutrino oscillations would therefore be an indirect indication of the idea of Grand Unification, and therefore of paramount importance. Neutrino oscillations occur when neutrinos acquire mass in such a way that the neutrino mass eigenstates do not match the (neutrino) eigenstates produced by the weak interactions. We shall study the ways in which neutrinos can get mass, first at the level of the standard SU 2 x U 1 model, then at the level of its Grand Unification Generalizations

Anharmonic oscillator and Bogoliubov transformation

International Nuclear Information System (INIS)

Pattnayak, G.C.; Torasia, S.; Rath, B.

1990-01-01

The anharmonic oscillator occupies a cornerstone in many problems in physics. It was observed that none of the authors have tested Bogoliubov transformation to study anharmonic oscillator. The groundstate energy of the anharmonic oscillator is studied using Bogoliubov transformation and the results presented. (author)

Observation and analysis of oscillations in linear accelerators

International Nuclear Information System (INIS)

Seeman, J.T.

1991-11-01

This report discusses the following on oscillation in linear accelerators: Betatron Oscillations; Betatron Oscillations at High Currents; Transverse Profile Oscillations; Transverse Profile Oscillations at High Currents.; Oscillation and Profile Transient Jitter; and Feedback on Transverse Oscillations

Anchoring samarium oxide nanoparticles on reduced graphene oxide for high-performance supercapacitor

Energy Technology Data Exchange (ETDEWEB)

Dezfuli, Amin Shiralizadeh [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Ganjali, Mohammad Reza, E-mail: ganjali@khayam.ut.ac.ir [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Biosensor Research Center, Endocrinology & Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Naderi, Hamid Reza [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of)

2017-04-30

Highlights: • Samarium oxide nanoparticles have been anchored on the surface of reduced graphene oxide for the first time. • Sm{sub 2}O{sub 3}/RGO nanocomposite show high capacitance, good rate and cycling performance. • Sm{sub 2}O{sub 3}/RGO nanocomposite can serve as efficient electrode material for energy storage. • The best composite electrode exhibits specific capacitance of 321 F g{sup −1} in 2 mV s{sup −1}. - Abstract: We have synthesized Sm{sub 2}O{sub 3} nanoparticles (SmNs) and anchored them onto the surface of reduced graphene oxide (RGO) through a self-assembly thereof by utilizing a facile sonochemical procedure. The nanomaterials were characterized by means of powder X-ray diffraction (XRD), Field-emission scanning electron microscopy (FE-SEM), fourier transform infrared spectroscopy (FT-IR) spectra, and X-ray photoelectron spectroscopy (XPS). As the next step, the supercapacitive behavior of the resulting nanocomposites were investigated when used as electrode material, through with cyclic voltammetric (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) techniques. The SmNs decorated RGO (SmN-RGO) nanocomposites were found to possess a specific capacitance (SC) of 321 F g{sup −1} when used in a 0.5 M Na{sub 2}SO{sub 4} solution as an electrolyte, in a scan rate of 2 mV s{sup −1}. The SC of the SmN-RGO based electrodes were also found to be 268 F g{sup −1} at a current density of 2 A g{sup −1} through galvanostatic charge-discharge tests. The outstanding properties of the SmN-RGOs were attributed to synergy of the high charge mobility of SmNs and the flexibility of the sheets of RGOs. Additionally, the nano-composite revealed a unique cycling durability (maintaining 99% of its SC even after 4000 cycles).

Modeling nonlinearities in MEMS oscillators.

Science.gov (United States)

Agrawal, Deepak K; Woodhouse, Jim; Seshia, Ashwin A

2013-08-01

We present a mathematical model of a microelectromechanical system (MEMS) oscillator that integrates the nonlinearities of the MEMS resonator and the oscillator circuitry in a single numerical modeling environment. This is achieved by transforming the conventional nonlinear mechanical model into the electrical domain while simultaneously considering the prominent nonlinearities of the resonator. The proposed nonlinear electrical model is validated by comparing the simulated amplitude-frequency response with measurements on an open-loop electrically addressed flexural silicon MEMS resonator driven to large motional amplitudes. Next, the essential nonlinearities in the oscillator circuit are investigated and a mathematical model of a MEMS oscillator is proposed that integrates the nonlinearities of the resonator. The concept is illustrated for MEMS transimpedance-amplifier- based square-wave and sine-wave oscillators. Closed-form expressions of steady-state output power and output frequency are derived for both oscillator models and compared with experimental and simulation results, with a good match in the predicted trends in all three cases.

On the mechanism of oscillations in neutrophils

DEFF Research Database (Denmark)

Brasen, Jens Christian; Barington, Torben; Olsen, Lars Folke

2010-01-01

We have investigated the regulation of the oscillatory generation of H(2)O(2) and oscillations in shape and size in neutrophils in suspension. The oscillations are independent of cell density and hence do not represent a collective phenomena. Furthermore, the oscillations are independent...... of the external glucose concentration and the oscillations in H(2)O(2) production are 180 degrees out of phase with the oscillations in NAD(P)H. Cytochalasin B blocked the oscillations in shape and size whereas it increased the period of the oscillations in H(2)O(2) production. 1- and 2-butanol also blocked...... the oscillations in shape and size, but only 1-butanol inhibited the oscillations in H(2)O(2) production. We conjecture that the oscillations are likely to be due to feedback regulations in the signal transduction cascade involving phosphoinositide 3-kinases (PI3K). We have tested this using a simple mathematical...

Primordial oscillations in life: Direct observation of glycolytic oscillations in individual HeLa cervical cancer cells

Science.gov (United States)

Amemiya, Takashi; Shibata, Kenichi; Itoh, Yoshihiro; Itoh, Kiminori; Watanabe, Masatoshi; Yamaguchi, Tomohiko

2017-10-01

We report the first direct observation of glycolytic oscillations in HeLa cervical cancer cells, which we regard as primordial oscillations preserved in living cells. HeLa cells starved of glucose or both glucose and serum exhibited glycolytic oscillations in nicotinamide adenine dinucleotide (NADH), exhibiting asynchronous intercellular behaviors. Also found were spatially homogeneous and inhomogeneous intracellular NADH oscillations in the individual cells. Our results demonstrate that starved HeLa cells may be induced to exhibit glycolytic oscillations by either high-uptake of glucose or the enhancement of a glycolytic pathway (Crabtree effect or the Warburg effect), or both. Their asynchronous collective behaviors in the oscillations were probably due to a weak intercellular coupling. Elucidation of the relationship between the mechanism of glycolytic dynamics in cancer cells and their pathophysiological characteristics remains a challenge in future.

The Wien Bridge Oscillator Family

DEFF Research Database (Denmark)

Lindberg, Erik

2006-01-01

A tutorial in which the Wien bridge family of oscillators is defined and investigated. Oscillators which do not fit into the Barkhausen criterion topology may be designed. A design procedure based on initial complex pole quality factor is reported. The dynamic transfer characteristic of the ampli......A tutorial in which the Wien bridge family of oscillators is defined and investigated. Oscillators which do not fit into the Barkhausen criterion topology may be designed. A design procedure based on initial complex pole quality factor is reported. The dynamic transfer characteristic...

Heat exchanger with oscillating flow

Science.gov (United States)

Scotti, Stephen J. (Inventor); Blosser, Max L. (Inventor); Camarda, Charles J. (Inventor)

1993-01-01

Various heat exchange apparatuses are described in which an oscillating flow of primary coolant is used to dissipate an incident heat flux. The oscillating flow may be imparted by a reciprocating piston, a double action twin reciprocating piston, fluidic oscillators or electromagnetic pumps. The oscillating fluid flows through at least one conduit in either an open loop or a closed loop. A secondary flow of coolant may be used to flow over the outer walls of at least one conduit to remove heat transferred from the primary coolant to the walls of the conduit.

Polymerization and oscillation stuttering in a filamentous model of the subcellular Min oscillation

Science.gov (United States)

Rutenberg, Andrew; Sengupta, Supratim; Sain, Anirban; Derr, Julien

2011-03-01

We present a computational model of the E. coli Min oscillation that involves polymerization of MinD filaments followed by depolymerization stimulated by filament-end zones of MinE. Our stochastic model is fully three-dimensional, and tracks the diffusion and interactions of every MinD and MinE molecule. We recover self-organized Min oscillations. We investigate the experimental phenomenon of oscillation stuttering, which we relate to the disruption of MinE tip-binding at the filament scale.

Oscillations in stellar atmospheres

International Nuclear Information System (INIS)

Costa, A.; Ringuelet, A.E.; Fontenla, J.M.

1989-01-01

Atmospheric excitation and propagation of oscillations are analyzed for typical pulsating stars. The linear, plane-parallel approach for the pulsating atmosphere gives a local description of the phenomenon. From the local analysis of oscillations, the minimum frequencies are obtained for radially propagating waves. The comparison of the minimum frequencies obtained for a variety of stellar types is in good agreement with the observed periods of the oscillations. The role of the atmosphere in the globar stellar pulsations is thus emphasized. 7 refs

Study of unstable valences of cadmium and samarium by pulse radiolysis. Influence of complexation by some synthetical ionophores

International Nuclear Information System (INIS)

Lerat-Parizot, O.

1992-01-01

Instable valences of cations in solution are evidenced by pulse radiolysis, in spite of a lifetime often lower than a milli-second they participate to electron transfer reactions, owing to their redox potential. In this work are studied Cd + and Sm 2+ obtained respectively by reduction of Cd 2+ and Sm 3+ by a solvated electron. The reactivity of Cd + in a cryptand and in a coronand is studied; it is a powerful reducing agent (redox potential -2V) going back to the stable valence by electron transfer to an acceptor. Transfer kinetics is studied by reduction of organic molecules, effect of solvents and ligands is also examined. For samarium the reduction kinetics by hydrated electrons is increased when the ion is in a cryptand in agreement with electrochemical observations, showing that the valence 2+ is stabilized in respect to the valence 3+ for lanthanides. The difference of behaviour between Cd + and Sm 2+ is probably due to the fact that for Cd the transferred electron comes from the external layer and for Sm it is a f electron protected by the 5s and 5p orbitals

Neuromorphic computing with nanoscale spintronic oscillators.

Science.gov (United States)

Torrejon, Jacob; Riou, Mathieu; Araujo, Flavio Abreu; Tsunegi, Sumito; Khalsa, Guru; Querlioz, Damien; Bortolotti, Paolo; Cros, Vincent; Yakushiji, Kay; Fukushima, Akio; Kubota, Hitoshi; Yuasa, Shinji; Stiles, Mark D; Grollier, Julie

2017-07-26

Neurons in the brain behave as nonlinear oscillators, which develop rhythmic activity and interact to process information. Taking inspiration from this behaviour to realize high-density, low-power neuromorphic computing will require very large numbers of nanoscale nonlinear oscillators. A simple estimation indicates that to fit 10 8 oscillators organized in a two-dimensional array inside a chip the size of a thumb, the lateral dimension of each oscillator must be smaller than one micrometre. However, nanoscale devices tend to be noisy and to lack the stability that is required to process data in a reliable way. For this reason, despite multiple theoretical proposals and several candidates, including memristive and superconducting oscillators, a proof of concept of neuromorphic computing using nanoscale oscillators has yet to be demonstrated. Here we show experimentally that a nanoscale spintronic oscillator (a magnetic tunnel junction) can be used to achieve spoken-digit recognition with an accuracy similar to that of state-of-the-art neural networks. We also determine the regime of magnetization dynamics that leads to the greatest performance. These results, combined with the ability of the spintronic oscillators to interact with each other, and their long lifetime and low energy consumption, open up a path to fast, parallel, on-chip computation based on networks of oscillators.

Rabi oscillation between states of a coupled harmonic oscillator

International Nuclear Information System (INIS)

Park, Tae Jun

2003-01-01

Rabi oscillation between bound states of a single potential is well known. However the corresponding formula between the states of two different potentials has not been obtained yet. In this work, we derive Rabi formula between the states of a coupled harmonic oscillator which may be used as a simple model for the electron transfer. The expression is similar to typical Rabi formula for a single potential. This result may be used to describe transitions between coupled diabatic potential curves

Transition from amplitude to oscillation death in a network of oscillators

International Nuclear Information System (INIS)

Nandan, Mauparna; Hens, C. R.; Dana, Syamal K.; Pal, Pinaki

2014-01-01

We report a transition from a homogeneous steady state (HSS) to inhomogeneous steady states (IHSSs) in a network of globally coupled identical oscillators. We perturb a synchronized population of oscillators in the network with a few local negative or repulsive mean field links. The whole population splits into two clusters for a certain number of repulsive mean field links and a range of coupling strength. For further increase of the strength of interaction, these clusters collapse into a HSS followed by a transition to IHSSs where all the oscillators populate either of the two stable steady states. We analytically determine the origin of HSS and its transition to IHSS in relation to the number of repulsive mean-field links and the strength of interaction using a reductionism approach to the model network. We verify the results with numerical examples of the paradigmatic Landau-Stuart limit cycle system and the chaotic Rössler oscillator as dynamical nodes. During the transition from HSS to IHSSs, the network follows the Turing type symmetry breaking pitchfork or transcritical bifurcation depending upon the system dynamics

Transition from amplitude to oscillation death in a network of oscillators

Energy Technology Data Exchange (ETDEWEB)

Nandan, Mauparna [Dr. B. C. Roy Engineering College, Durgapur 713206 (India); Department of Mathematics, National Institute of Technology, Durgapur 713209 (India); Hens, C. R.; Dana, Syamal K. [CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata 700032 (India); Pal, Pinaki [Department of Mathematics, National Institute of Technology, Durgapur 713209 (India)

2014-12-01

We report a transition from a homogeneous steady state (HSS) to inhomogeneous steady states (IHSSs) in a network of globally coupled identical oscillators. We perturb a synchronized population of oscillators in the network with a few local negative or repulsive mean field links. The whole population splits into two clusters for a certain number of repulsive mean field links and a range of coupling strength. For further increase of the strength of interaction, these clusters collapse into a HSS followed by a transition to IHSSs where all the oscillators populate either of the two stable steady states. We analytically determine the origin of HSS and its transition to IHSS in relation to the number of repulsive mean-field links and the strength of interaction using a reductionism approach to the model network. We verify the results with numerical examples of the paradigmatic Landau-Stuart limit cycle system and the chaotic Rössler oscillator as dynamical nodes. During the transition from HSS to IHSSs, the network follows the Turing type symmetry breaking pitchfork or transcritical bifurcation depending upon the system dynamics.

Oscillating universe with quintom matter

International Nuclear Information System (INIS)

Xiong Huahui; Cai Yifu; Qiu Taotao; Piao Yunsong; Zhang Xinmin

2008-01-01

In this Letter, we study the possibility of building a model of the oscillating universe with quintom matter in the framework of 4-dimensional Friedmann-Robertson-Walker background. Taking the two-scalar-field quintom model as an example, we find in the model parameter space there are five different types of solutions which correspond to: (I) a cyclic universe with the minimal and maximal values of the scale factor remaining the same in every cycle, (II) an oscillating universe with its minimal and maximal values of the scale factor increasing cycle by cycle, (III) an oscillating universe with its scale factor always increasing, (IV) an oscillating universe with its minimal and maximal values of the scale factor decreasing cycle by cycle, and (V) an oscillating universe with its scale factor always decreasing

Improved memristor-based relaxation oscillator

KAUST Repository

Mosad, Ahmed G.

2013-09-01

This paper presents an improved memristor-based relaxation oscillator which offers higher frequency and wider tunning range than the existing reactance-less oscillators. It also has the capability of operating on two positive supplies or alternatively a positive and negative supply. Furthermore, it has the advantage that it can be fully integrated on-chip providing an area-efficient solution. On the other hand, The oscillation concept is discussed then a complete mathematical analysis of the proposed oscillator is introduced. Furthermore, the power consumption of the new relaxation circuit is discussed and validated by the PSPICE circuit simulations showing an excellent agreement. MATLAB results are also introduced to demonstrate the resistance range and the corresponding frequency range which can be obtained from the proposed relaxation oscillator. © 2013 Elsevier Ltd.

The supersymmetric Pegg-Barnett oscillator

International Nuclear Information System (INIS)

Shen, Jian Qi

2005-01-01

The su(n) Lie algebraic structure of the Pegg-Barnett oscillator that possesses a finite-dimensional number-state space is demonstrated. The supersymmetric generalization of the Pegg-Barnett oscillator is suggested. it is shown that such a supersymmetric Pegg-Barnett oscillator may have some potential applications, e.g., the mass spectrum of the charged leptons

LSND neutrino oscillation results

International Nuclear Information System (INIS)

Louis, W.C.

1996-01-01

In the past several years, a number of experiments have searched for neutrino oscillations, where a neutrino of one type (say bar ν μ ) spontaneously transforms into a neutrino of another type (say bar ν e ). For this phenomenon to occur, neutrinos must be massive and the apparent conservation law of lepton families must be violated. In 1995 the LSND experiment published data showing candidate events that are consistent with bar ν μ oscillations. Additional data are reported here which provide stronger evidence for neutrino oscillations

Some comparison of two fractional oscillators

International Nuclear Information System (INIS)

Kang Yonggang; Zhang Xiu'e

2010-01-01

The other form of fractional oscillator equation comparing to the widely discussed one is ushered in. The properties of vibration of two fractional oscillators are discussed under the influence of different initial conditions. The interpretation of the characteristics of the fractional oscillators using different method is illustrated. Based on two fractional oscillator equations, two linked bodies and the continuous system are studied.

Do muons oscillate?

International Nuclear Information System (INIS)

Dolgov, A.D.; Morozov, A.Yu.; Okun, L.B.; Schepkin, M.G.

1997-01-01

We develop a theory of the EPR-like effects due to neutrino oscillations in the π→μν decays. Its experimental implications are space-time correlations of the neutrino and muon when they are both detected, while the pion decay point is not fixed. However, the more radical possibility of μ-oscillations in experiments where only muons are detected (as suggested in hep-ph/9509261), is ruled out. We start by discussing decays of monochromatic pions, and point out a few ''paradoxes''. Then we consider pion wave packets, solve the ''paradoxes'', and show that the formulas for μν correlations can be transformed into the usual expressions, describing neutrino oscillations, as soon as the pion decay point is fixed. (orig.)

Parametric oscillators from factorizations employing a constant-shifted Riccati solution of the classical harmonic oscillator

Energy Technology Data Exchange (ETDEWEB)

Rosu, H.C., E-mail: hcr@ipicyt.edu.mx [IPICyT, Instituto Potosino de Investigacion Cientifica y Tecnologica, Apdo Postal 3-74 Tangamanga, 78231 San Luis Potosi, S.L.P. (Mexico); Khmelnytskaya, K.V. [Universidad Autonoma de Queretaro, Centro Universitario, Cerro de las Campanas s/n, C.P. 76010 Santiago de Queretaro, Qro. (Mexico)

2011-09-19

We determine the kind of parametric oscillators that are generated in the usual factorization procedure of second-order linear differential equations when one introduces a constant shift of the Riccati solution of the classical harmonic oscillator. The mathematical results show that some of these oscillators could be of physical nature. We give the solutions of the obtained second-order differential equations and the values of the shift parameter providing strictly periodic and antiperiodic solutions. We also notice that this simple problem presents parity-time (PT) symmetry. Possible applications are mentioned. -- Highlights: → A particular Riccati solution of the classical harmonic oscillator is shifted by a constant. → Such a solution is used in the factorization brackets to get different equations of motion. → The properties of the parametric oscillators obtained in this way are examined.

Nonlinear oscillations

CERN Document Server

Nayfeh, Ali Hasan

1995-01-01

Nonlinear Oscillations is a self-contained and thorough treatment of the vigorous research that has occurred in nonlinear mechanics since 1970. The book begins with fundamental concepts and techniques of analysis and progresses through recent developments and provides an overview that abstracts and introduces main nonlinear phenomena. It treats systems having a single degree of freedom, introducing basic concepts and analytical methods, and extends concepts and methods to systems having degrees of freedom. Most of this material cannot be found in any other text. Nonlinear Oscillations uses sim

Memristor-based relaxation oscillators using digital gates

KAUST Repository

Khatib, Moustafa A.

2012-11-01

This paper presents two memristor-based relaxation oscillators. The proposed oscillators are designed without the need of any reactive elements, i.e., capacitor or inductor. As the \\'resistance storage\\' property of the memristor can be exploited to generate the oscillation. The proposed oscillators have the advantage that they can be fully integrated on-chip giving an area-efficient solution. Furthermore, these oscillators give higher frequency other than the existing reactance-less oscillator and provide a wider range of the resistance. The concept of operation and the mathematical analysis for the proposed oscillators are explained and verified with circuit simulations showing an excellent agreement. © 2012 IEEE.

Pattern formation in arrays of chemical oscillators

Indian Academy of Sciences (India)

Chemical oscillators; phase flip; oscillation death. PACS No. 05.45 .... array oscillate (with varying amplitudes and frequencies), while the others experience oscillation death .... Barring the boundary cells, one observes near phase flip and near ...

Low-frequency oscillations in Hall thrusters

International Nuclear Information System (INIS)

Wei Li-Qiu; Han Liang; Yu Da-Ren; Guo Ning

2015-01-01

In this paper, we summarize the research development of low-frequency oscillations in the last few decades. The findings of physical mechanism, characteristics and stabilizing methods of low-frequency oscillations are discussed. It shows that it is unreasonable and incomplete to model an ionization region separately to analyze the physical mechanism of low-frequency oscillations. Electro-dynamics as well as the formation conditions of ionization distribution play an important role in characteristics and stabilizing of low-frequency oscillations. Understanding the physical mechanism and characteristics of low- frequency oscillations thoroughly and developing a feasible method stabilizing this instability are still important research subjects. (review)

Coupled oscillators with parity-time symmetry

Energy Technology Data Exchange (ETDEWEB)

Tsoy, Eduard N., E-mail: etsoy@uzsci.net

2017-02-05

Different models of coupled oscillators with parity-time (PT) symmetry are studied. Hamiltonian functions for two and three linear oscillators coupled via coordinates and accelerations are derived. Regions of stable dynamics for two coupled oscillators are obtained. It is found that in some cases, an increase of the gain-loss parameter can stabilize the system. A family of Hamiltonians for two coupled nonlinear oscillators with PT-symmetry is obtained. An extension to high-dimensional PT-symmetric systems is discussed. - Highlights: • A generalization of a Hamiltonian system of linear coupled oscillators with the parity-time (PT) symmetry is suggested. • It is found that an increase of the gain-loss parameter can stabilize the system. • A family of Hamiltonian functions for two coupled nonlinear oscillators with PT-symmetry is obtained.

Samarium-modified vanadium phosphate catalyst for the selective oxidation of n-butane to maleic anhydride

International Nuclear Information System (INIS)

Wu, Hua-Yi; Wang, Hai-Bo; Liu, Xin-Hua; Li, Jian-Hui; Yang, Mei-Hua; Huang, Chuan-Jing; Weng, Wei-Zheng; Wan, Hui-Lin

2015-01-01

Graphical abstract: The addition of a small amount of Sm into VPO catalyst brought about great changes in its physicochemical properties such as surface area, surface morphology, phase composition and redox property, thus leading to a higher catalytic performance in the selective oxidation of n-butane to maleic anhydride, as compared to the undoped VPO catalyst. - Highlights: • The addition of Sm leads to great changes in the structure of VPO catalyst. • Sm improves performance of VPO for oxidation of n-butane to maleic anhydride. • Catalytic performance is closely related to structure of VPO catalyst. - Abstract: A series of samarium-modified vanadium phosphate catalysts were prepared and studied in selective oxidation of n-butane to maleic anhydride. The catalytic evaluation showed that Sm modification significantly increased the overall n-butane conversion and intrinsic activity. N 2 -adsorption, XRD, SEM, Raman, XPS, EPR and H 2 -TPR techniques were used to investigate the intrinsic difference among these catalysts. The results revealed that the addition of Sm to VPO catalyst can increase the surface area of the catalyst, lead to a significant change in catalyst morphology from plate-like structure into rosette-shape clusters, and largely promote the formation of (VO) 2 P 2 O 7 . All of these were related to the different catalytic performance of Sm-doped and undoped VPO catalysts. The roles of the different VOPO 4 phases and the influence of Sm were also described and discussed

Slow oscillations orchestrating fast oscillations and memory consolidation.

Science.gov (United States)

Mölle, Matthias; Born, Jan

2011-01-01

Slow-wave sleep (SWS) facilitates the consolidation of hippocampus-dependent declarative memory. Based on the standard two-stage memory model, we propose that memory consolidation during SWS represents a process of system consolidation which is orchestrated by the neocortical memory. The slow oscillations temporally group neuronal activity into up-states of strongly enhanced neuronal activity and down-states of neuronal silence. In a feed-forward efferent action, this grouping is induced not only in the neocortex but also in other structures relevant to consolidation, namely the thalamus generating 10-15Hz spindles, and the hippocampus generating sharp wave-ripples, with the latter well known to accompany a replay of newly encoded memories taking place in hippocampal circuitries. The feed-forward synchronizing effect of the slow oscillation enables the formation of spindle-ripple events where ripples and accompanying reactivated hippocampal memory information become nested into the single troughs of spindles. Spindle-ripple events thus enable reactivated memory-related hippocampal information to be fed back to neocortical networks in the excitable slow oscillation up-state where they can induce enduring plastic synaptic changes underlying the effective formation of long-term memories. Copyright © 2011 Elsevier B.V. All rights reserved.

A theory of generalized Bloch oscillations

DEFF Research Database (Denmark)

Duggen, Lars; Lew Yan Voon, L. C.; Lassen, Benny

2016-01-01

Bloch oscillations of electrons are shown to occur for cases when the energy spectrum does not consist of the traditional evenly-spaced ladders and the potential gradient does not result from an external electric field. A theory of such generalized Bloch oscillations is presented and an exact...... oscillations. We stipulate that the presented theory of generalized Bloch oscillations can be extended to other systems such as acoustics and photonics....

TOWARDS THRESHOLD FREQUENCY IN CHAOTIC COLPITTS OSCILLATOR

DEFF Research Database (Denmark)

Lindberg, Erik; Tamasevicius, Arunas; Mykolaitis, Gytis

2007-01-01

A novel version of chaotic Colpitts oscillator is described. Instead of a linear loss resistor, it includes an extra inductor and diode in the collector circuit of the transistor. The modified circuit in comparison with the common Colpitts oscillator may generate chaotic oscillations at the funda......A novel version of chaotic Colpitts oscillator is described. Instead of a linear loss resistor, it includes an extra inductor and diode in the collector circuit of the transistor. The modified circuit in comparison with the common Colpitts oscillator may generate chaotic oscillations...

pH-regulated chemical oscillators.

Science.gov (United States)

Orbán, Miklós; Kurin-Csörgei, Krisztina; Epstein, Irving R

2015-03-17

The hydrogen ion is arguably the most ubiquitous and important species in chemistry. It also plays a key role in nearly every biological process. In this Account, we discuss systems whose behavior is governed by oscillations in the concentration of hydrogen ion. The first chemical oscillators driven by changes in pH were developed a quarter century ago. Since then, about two dozen new pH oscillators, systems in which the periodic variation in pH is not just an indicator but an essential prerequisite of the oscillatory behavior, have been discovered. Mechanistic understanding of their behavior has grown, and new ideas for their practical application have been proposed and, in some cases, tested. Here we present a catalog of the known pH oscillators, divide them into mechanistically based categories based on whether they involve a single oxidant and reductant or an oxidant and a pair of reductants, and describe general mechanisms for these two major classes of systems. We also describe in detail the chemistry of one example from each class, hydrogen peroxide-sulfide and ferricyanide-iodate-sulfite. Finally, we consider actual and potential applications. These include using pH oscillators to induce oscillation in species that would otherwise be nonoscillatory, creating novel spatial patterns, generating periodic transitions between vesicle and micelle states, stimulating switching between folded and random coil states of DNA, building molecular motors, and designing pulsating drug delivery systems. We point out the importance for future applications of finding a batch pH oscillator, one that oscillates in a closed system for an extended period of time, and comment on the progress that has been made toward that goal.

On the Dirac oscillator

International Nuclear Information System (INIS)

Rodrigues, R. de Lima

2007-01-01

In the present work we obtain a new representation for the Dirac oscillator based on the Clifford algebra C 7. The symmetry breaking and the energy eigenvalues for our model of the Dirac oscillator are studied in the non-relativistic limit. (author)

Exact folded-band chaotic oscillator.

Science.gov (United States)

Corron, Ned J; Blakely, Jonathan N

2012-06-01

An exactly solvable chaotic oscillator with folded-band dynamics is shown. The oscillator is a hybrid dynamical system containing a linear ordinary differential equation and a nonlinear switching condition. Bounded oscillations are provably chaotic, and successive waveform maxima yield a one-dimensional piecewise-linear return map with segments of both positive and negative slopes. Continuous-time dynamics exhibit a folded-band topology similar to Rössler's oscillator. An exact solution is written as a linear convolution of a fixed basis pulse and a discrete binary sequence, from which an equivalent symbolic dynamics is obtained. The folded-band topology is shown to be dependent on the symbol grammar.

Unstable oscillators based hyperchaotic circuit

DEFF Research Database (Denmark)

Murali, K.; Tamasevicius, A.; G. Mykolaitis, A.

1999-01-01

A simple 4th order hyperchaotic circuit with unstable oscillators is described. The circuit contains two negative impedance converters, two inductors, two capacitors, a linear resistor and a diode. The Lyapunov exponents are presented to confirm hyperchaotic nature of the oscillations in the circ...... in the circuit. The performance of the circuit is investigated by means of numerical integration of appropriate differential equations, PSPICE simulations, and hardware experiment.......A simple 4th order hyperchaotic circuit with unstable oscillators is described. The circuit contains two negative impedance converters, two inductors, two capacitors, a linear resistor and a diode. The Lyapunov exponents are presented to confirm hyperchaotic nature of the oscillations...

Dgroup: DG01196 [KEGG MEDICUS

Lifescience Database Archive (English)

Full Text Available DG01196 Chemical ... DGroup Samarium (153Sm) lexidronam ... D08504 ... Samarium (153Sm) lexidron...am (INN) D05795 ... Samarium Sm 153 lexidronam pentasodium (USAN); Samarium (153Sm) lexidronam sodium (JA

A Survey on Forced Oscillations in Power System

OpenAIRE

Ghorbaniparvar, Mohammadreza

2016-01-01

Oscillations in a power system can be categorized into free oscillations and forced oscillations. Many algorithms have been developed to estimate the modes of free oscillations in a power system. Recently, forced oscillations caught many attentions. Techniques are proposed to detect forced oscillations and locate their sources. In addition, forced oscillations may have negative impact on the estimation of mode and mode-shape if they are not properly accounted for. To improve the power system ...

Neutrino oscillations. Theory and experiment

International Nuclear Information System (INIS)

Beshtoev, Kh.M.

2001-01-01

Theoretical schemes on neutrino oscillations are considered. The experimental data on neutrino oscillations obtained in the Super-Kamiokande (Japan) and SNO (Canada) experiments are given. Comparison of these data with the predictions obtained in the theoretical schemes is done. Conclusion is made that the experimental data confirm only the scheme with transitions (oscillations) between aromatic ν e -, ν μ -, ν τ - neutrinos with maximal angle mixings. (author)

Reactor oscillator - I - III, Part III - Electronic device; Reaktorski oscilator - I-III, III Deo - Elektronski uredjaj

Energy Technology Data Exchange (ETDEWEB)

Lolic, B; Jovanovic, S [Institute of Nuclear Sciences Boris Kidric, Laboratorija za fiziku reaktora, Vinca, Beograd (Serbia and Montenegro)

1961-12-15

This report describes functioning of the reactor oscillator electronic system. Two methods of oscillator operation were discussed. The first method is so called method of amplitude modulation of the reactor power, and the second newer method is phase method. Both methods are planned for the present reactor oscillator.

Pile oscillator ROB-1, cooperation NPY

Energy Technology Data Exchange (ETDEWEB)

Petrovic, M; Markovic, V; Obradovic, D; Kocic, A; Velickovic, LJ; Jovanovic, S [Boris Kidric Institute of nuclear sciences Vinca, Belgrade (Yugoslavia)

1965-11-15

The present paper explains the purpose of the work on reactor kinetics and separately deals with the region for which the ROB-1 reactor oscillator is constructed. The theoretical part concerns the basic principles on which the oscillator operates. the paper also discusses the details of the oscillator, the procedure for preparation and measurement, and analyzes the source of errors. In addition several examples of the use of oscillator are given. (author)

Pile oscillator ROB-1, cooperation NPY

International Nuclear Information System (INIS)

Petrovic, M.; Markovic, V.; Obradovic, D.; Kocic, A.; Velickovic, LJ.; Jovanovic, S.

1965-11-01

The present paper explains the purpose of the work on reactor kinetics and separately deals with the region for which the ROB-1 reactor oscillator is constructed. The theoretical part concerns the basic principles on which the oscillator operates. the paper also discusses the details of the oscillator, the procedure for preparation and measurement, and analyzes the source of errors. In addition several examples of the use of oscillator are given. (author)

Nonlocal synchronization in nearest neighbour coupled oscillators

International Nuclear Information System (INIS)

El-Nashar, H.F.; Elgazzar, A.S.; Cerdeira, H.A.

2002-02-01

We investigate a system of nearest neighbour coupled oscillators. We show that the nonlocal frequency synchronization, that might appear in such a system, occurs as a consequence of the nearest neighbour coupling. The power spectra of nonadjacent oscillators shows that there is no complete coincidence between all frequency peaks of the oscillators in the nonlocal cluster, while the peaks for neighbouring oscillators approximately coincide even if they are not yet in a cluster. It is shown that nonadjacent oscillators closer in frequencies, share slow modes with their adjacent oscillators which are neighbours in space. It is also shown that when a direct coupling between non-neighbours oscillators is introduced explicitly, the peaks of the spectra of the frequencies of those non-neighbours coincide. (author)

Observation of Quasichanneling Oscillations

International Nuclear Information System (INIS)

Wistisen, T. N.; Mikkelsen, R. E.; Uggerhoj, University I.; Wienands, University; Markiewicz, T. W.

2017-01-01

Here, we report on the first experimental observations of quasichanneling oscillations, recently seen in simulations and described theoretically. Although above-barrier particles penetrating a single crystal are generally seen as behaving almost as in an amorphous substance, distinct oscillation peaks nevertheless appear for particles in that category. The quasichanneling oscillations were observed at SLAC National Accelerator Laboratory by aiming 20.35 GeV positrons and electrons at a thin silicon crystal bent to a radius of R = 0.15 m, exploiting the quasimosaic effect. For electrons, two relatively faint quasichanneling peaks were observed, while for positrons, seven quasichanneling peaks were clearly identified.

Mutual phase-locking of planar nano-oscillators

Directory of Open Access Journals (Sweden)

K. Y. Xu

2014-06-01

Full Text Available Characteristics of phase-locking between Gunn effect-based planar nano-oscillators are studied using an ensemble Monte Carlo (EMC method. Directly connecting two oscillators in close proximity, e.g. with a channel distance of 200 nm, only results in incoherent oscillations. In order to achieve in-phase oscillations, additional considerations must be taken into account. Two coupling paths are shown to exist between oscillators. One coupling path results in synchronization and the other results in anti-phase locking. The coupling strength through these two paths can be adjusted by changing the connections between oscillators. When two identical oscillators are in the anti-phase locking regime, fundamental components of oscillations are cancelled. The resulting output consists of purely second harmonic oscillations with a frequency of about 0.66 THz. This type of second harmonic generation is desired for higher frequency applications since no additional filter system is required. This transient phase-locking process is further analyzed using Adler's theory. The locking range is extracted, and a criterion for the channel length difference required for realizing phased arrays is obtained. This work should aid in designing nano-oscillator arrays for high power applications and developing directional transmitters for wireless communications.

Neutrino oscillations at proton accelerators

International Nuclear Information System (INIS)

Michael, Douglas

2002-01-01

Data from many different experiments have started to build a first glimpse of the phenomenology associated with neutrino oscillations. Results on atmospheric and solar neutrinos are particularly clear while a third result from LSND suggests a possibly very complex oscillation phenomenology. As impressive as the results from current experiments are, it is clear that we are just getting started on a long-term experimental program to understand neutrino masses, mixings and the physics which produce them. A number of exciting fundamental physics possibilities exist, including that neutrino oscillations could demonstrate CP or CPT violation and could be tied to exotic high-energy phenomena including strings and extra dimensions. A complete exploration of oscillation phenomena demands many experiments, including those possible using neutrino beams produced at high energy proton accelerators. Most existing neutrino experiments are statistics limited even though they use gigantic detectors. High intensity proton beams are essential for producing the intense neutrino beams which we need for next generation neutrino oscillation experiments

Neutrino Oscillations at Proton Accelerators

Science.gov (United States)

Michael, Douglas

2002-12-01

Data from many different experiments have started to build a first glimpse of the phenomenology associated with neutrino oscillations. Results on atmospheric and solar neutrinos are particularly clear while a third result from LSND suggests a possibly very complex oscillation phenomenology. As impressive as the results from current experiments are, it is clear that we are just getting started on a long-term experimental program to understand neutrino masses, mixings and the physics which produce them. A number of exciting fundamental physics possibilities exist, including that neutrino oscillations could demonstrate CP or CPT violation and could be tied to exotic high-energy phenomena including strings and extra dimensions. A complete exploration of oscillation phenomena demands many experiments, including those possible using neutrino beams produced at high energy proton accelerators. Most existing neutrino experiments are statistics limited even though they use gigantic detectors. High intensity proton beams are essential for producing the intense neutrino beams which we need for next generation neutrino oscillation experiments.

Nonlinear analysis of ring oscillator circuits

KAUST Repository

Ge, Xiaoqing

2010-06-01

Using nonlinear systems techniques, we analyze the stability properties and synchronization conditions for ring oscillator circuits, which are essential building blocks in digital systems. By making use of its cyclic structure, we investigate local and global stability properties of an n-stage ring oscillator. We present a sufficient condition for global asymptotic stability of the origin and obtain necessity if the ring oscillator consists of identical inverter elements. We then give a synchronization condition for identical interconnected ring oscillators.

Nonlinear analysis of ring oscillator circuits

KAUST Repository

Ge, Xiaoqing; Arcak, Murat; Salama, Khaled N.

2010-01-01

Using nonlinear systems techniques, we analyze the stability properties and synchronization conditions for ring oscillator circuits, which are essential building blocks in digital systems. By making use of its cyclic structure, we investigate local and global stability properties of an n-stage ring oscillator. We present a sufficient condition for global asymptotic stability of the origin and obtain necessity if the ring oscillator consists of identical inverter elements. We then give a synchronization condition for identical interconnected ring oscillators.

Phase-locked Josephson soliton oscillators

DEFF Research Database (Denmark)

Holst, T.; Hansen, Jørn Bindslev; Grønbech-Jensen, N.

1991-01-01

Detailed experimental characterization of the phase-locking at both DC and at microwave frequencies is presented for two closely spaced Josephson soliton (fluxon) oscillators. In the phase-locked state, the radiated microwave power exhibited an effective gain. With one common bias source......, a frequency tunability of the phase-locked oscillators up to 7% at 10 GHz was observed. The interacting soliton oscillators were modeled by two inductively coupled nonlinear transmission lines...

Stable And Oscillating Acoustic Levitation

Science.gov (United States)

Barmatz, Martin B.; Garrett, Steven L.

1988-01-01

Sample stability or instability determined by levitating frequency. Degree of oscillation of acoustically levitated object along axis of levitation chamber controlled by varying frequency of acoustic driver for axis above or below frequency of corresponding chamber resonance. Stabilization/oscillation technique applied in normal Earth gravity, or in absence of gravity to bring object quickly to rest at nominal levitation position or make object oscillate in desired range about that position.

Umbral oscillations as a probe of sunspot

International Nuclear Information System (INIS)

Abdelatif, T.E.H.

1985-01-01

The interaction of the solar five-minute oscillations with a sunspot is thoroughly explored, both on observational and theoretical grounds. Simple theoretical models are developed in order to understand the observations of umbral oscillations. Observations made at the National Solar Observatory detected both the three-minute and five-minute umbral oscillations at photospheric heights. The three-minute oscillations were found to have a kinetic energy density six times higher in the photosphere than in the chromosphere and to be concentrated in the central part of the umbra, supporting the photospheric resonance theory for the three-minute umbral oscillations. The five-minute oscillations are attenuated in the umbra, which appears to act as a filter in selecting some of the peaks in the power spectrum of five-minute oscillations in the surrounding photosphere. The k-omega power spectrum of the umbral oscillations shows a shift of power to longer wavelengths. Theoretical models of the transmission of acoustic waves into a magnetic region explain both observed effects

Lepton asymmetry and neutrino oscillations interplay

Energy Technology Data Exchange (ETDEWEB)

Kirilova, Daniela, E-mail: dani@astro.bas.bg [Bulgarian Academy of Sciences, Institute of Astronomy and NAO (Bulgaria)

2013-03-15

We discuss the interplay between lepton asymmetry L and {nu} oscillations in the early Universe. Neutrino oscillations may suppress or enhance previously existing L. On the other hand L is capable to suppress or enhance neutrino oscillations. The mechanism of L enhancement in MSW resonant {nu} oscillations in the early Universe is numerically analyzed. L cosmological effects through {nu} oscillations are discussed. We discuss how L may change the cosmological BBN constraints on neutrino and show that BBN model with {nu}{sub e}{r_reversible}{nu}{sub s} oscillations is extremely sensitive to L - it allows to obtain the most stringent constraints on L value. We discuss also the cosmological role of active-sterile {nu} mixing and L in connection with the indications about additional relativistic density in the early Universe, pointed out by BBN, CMB and LSS data and the analysis of global {nu} data.

Rayleigh-type parametric chemical oscillation

Energy Technology Data Exchange (ETDEWEB)

Ghosh, Shyamolina; Ray, Deb Shankar, E-mail: pcdsr@iacs.res.in [Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

2015-09-28

We consider a nonlinear chemical dynamical system of two phase space variables in a stable steady state. When the system is driven by a time-dependent sinusoidal forcing of a suitable scaling parameter at a frequency twice the output frequency and the strength of perturbation exceeds a threshold, the system undergoes sustained Rayleigh-type periodic oscillation, wellknown for parametric oscillation in pipe organs and distinct from the usual forced quasiperiodic oscillation of a damped nonlinear system where the system is oscillatory even in absence of any external forcing. Our theoretical analysis of the parametric chemical oscillation is corroborated by full numerical simulation of two well known models of chemical dynamics, chlorite-iodine-malonic acid and iodine-clock reactions.

Rayleigh-type parametric chemical oscillation.

Science.gov (United States)

Ghosh, Shyamolina; Ray, Deb Shankar

2015-09-28

We consider a nonlinear chemical dynamical system of two phase space variables in a stable steady state. When the system is driven by a time-dependent sinusoidal forcing of a suitable scaling parameter at a frequency twice the output frequency and the strength of perturbation exceeds a threshold, the system undergoes sustained Rayleigh-type periodic oscillation, wellknown for parametric oscillation in pipe organs and distinct from the usual forced quasiperiodic oscillation of a damped nonlinear system where the system is oscillatory even in absence of any external forcing. Our theoretical analysis of the parametric chemical oscillation is corroborated by full numerical simulation of two well known models of chemical dynamics, chlorite-iodine-malonic acid and iodine-clock reactions.

Nonlinearity induced synchronization enhancement in mechanical oscillators

Science.gov (United States)

Czaplewski, David A.; Lopez, Omar; Guest, Jeffrey R.; Antonio, Dario; Arroyo, Sebastian I.; Zanette, Damian H.

2018-05-08

An autonomous oscillator synchronizes to an external harmonic force only when the forcing frequency lies within a certain interval, known as the synchronization range, around the oscillator's natural frequency. Under ordinary conditions, the width of the synchronization range decreases when the oscillation amplitude grows, which constrains synchronized motion of micro- and nano-mechanical resonators to narrow frequency and amplitude bounds. The present invention shows that nonlinearity in the oscillator can be exploited to manifest a regime where the synchronization range increases with an increasing oscillation amplitude. The present invention shows that nonlinearities in specific configurations of oscillator systems, as described herein, are the key determinants of the effect. The present invention presents a new configuration and operation regime that enhances the synchronization of micro- and nano-mechanical oscillators by capitalizing on their intrinsic nonlinear dynamics.

Integrated optoelectronic oscillator.

Science.gov (United States)

Tang, Jian; Hao, Tengfei; Li, Wei; Domenech, David; Baños, Rocio; Muñoz, Pascual; Zhu, Ninghua; Capmany, José; Li, Ming

2018-04-30

With the rapid development of the modern communication systems, radar and wireless services, microwave signal with high-frequency, high-spectral-purity and frequency tunability as well as microwave generator with light weight, compact size, power-efficient and low cost are increasingly demanded. Integrated microwave photonics (IMWP) is regarded as a prospective way to meet these demands by hybridizing the microwave circuits and the photonics circuits on chip. In this article, we propose and experimentally demonstrate an integrated optoelectronic oscillator (IOEO). All of the devices needed in the optoelectronic oscillation loop circuit are monolithically integrated on chip within size of 5×6cm 2 . By tuning the injection current to 44 mA, the output frequency of the proposed IOEO is located at 7.30 GHz with phase noise value of -91 dBc/Hz@1MHz. When the injection current is increased to 65 mA, the output frequency can be changed to 8.87 GHz with phase noise value of -92 dBc/Hz@1MHz. Both of the oscillation frequency can be slightly tuned within 20 MHz around the center oscillation frequency by tuning the injection current. The method about improving the performance of IOEO is carefully discussed at the end of in this article.

Chemical sensor with oscillating cantilevered probe

Science.gov (United States)

Adams, Jesse D

2013-02-05

The invention provides a method of detecting a chemical species with an oscillating cantilevered probe. A cantilevered beam is driven into oscillation with a drive mechanism coupled to the cantilevered beam. A free end of the oscillating cantilevered beam is tapped against a mechanical stop coupled to a base end of the cantilevered beam. An amplitude of the oscillating cantilevered beam is measured with a sense mechanism coupled to the cantilevered beam. A treated portion of the cantilevered beam is exposed to the chemical species, wherein the cantilevered beam bends when exposed to the chemical species. A second amplitude of the oscillating cantilevered beam is measured, and the chemical species is determined based on the measured amplitudes.

Oscillations of the Outer Boundary of the Outer Radiation Belt During Sawtooth Oscillations

Directory of Open Access Journals (Sweden)

Jae-Hun Kim

2006-09-01

Full Text Available We report three sawtooth oscillation events observed at geosynchronous orbit where we find quasi-periodic (every 2-3 hours sudden flux increases followed by slow flux decreases at the energy levels of ˜50-400 keV. For these three sawtooth events, we have examined variations of the outer boundary of the outer radiation belt. In order to determine L values of the outer boundary, we have used data of relativistic electron flux observed by the SAMPEX satellite. We find that the outer boundary of the outer radiation belt oscillates periodically being consistent with sawtooth oscillation phases. Specifically, the outer boundary of the outer radiation belt expands (namely, the boundary L value increases following the sawtooth particle flux enhancement of each tooth, and then contracts (namely, the boundary L value decreases while the sawtooth flux decreases gradually until the next flux enhancement. On the other hand, it is repeatedly seen that the asymmetry of the magnetic field intensity between dayside and nightside decreases (increases due to the dipolarization (the stretching on the nightside as the sawtooth flux increases (decreases. This implies that the periodic magnetic field variations during the sawtooth oscillations are likely responsible for the expansion-contraction oscillations of the outer boundary of the outer radiation belt.

Sustaining GHz oscillation of carbon nanotube based oscillators via a MHz frequency excitation

International Nuclear Information System (INIS)

Motevalli, Benyamin; Taherifar, Neda; Liu, Jefferson Zhe

2016-01-01

There have been intensive studies to investigate the properties of gigahertz nano-oscillators based on multi-walled carbon nanotubes (MWCNTs). Many of these studies, however, revealed that the unique telescopic translational oscillations in such devices would damp quickly due to various energy dissipation mechanisms. This challenge remains the primary obstacle against its practical applications. Herein, we propose a design concept in which a GHz oscillation could be re-excited by a MHz mechanical motion. This design involves a triple-walled CNT, in which sliding of the longer inner tube at a MHz frequency can re-excite and sustain a GHz oscillation of the shorter middle tube. Our molecular dynamics (MD) simulations prove this design concept at ∼10 nm scale. A mathematical model is developed to explore the feasibility at a larger size scale. As an example, in an oscillatory system with the CNT’s length above 100 nm, the high oscillatory frequency range of 1.8–3.3 GHz could be excited by moving the inner tube at a much lower frequency of 53.4 MHz. This design concept together with the mechanical model could energize the development of GHz nano-oscillators in miniaturized electro-mechanical devices. (paper)

Comparison of Methods for Oscillation Detection

DEFF Research Database (Denmark)

Odgaard, Peter Fogh; Trangbæk, Klaus

2006-01-01

This paper compares a selection of methods for detecting oscillations in control loops. The methods are tested on measurement data from a coal-fired power plant, where some oscillations are occurring. Emphasis is put on being able to detect oscillations without having a system model and without...... using process knowledge. The tested methods show potential for detecting the oscillations, however, transient components in the signals cause false detections as well, motivating usage of models in order to remove the expected signals behavior....

Density-wave oscillations

International Nuclear Information System (INIS)

Belblidia, L.A.; Bratianu, C.

1979-01-01

Boiling flow in a steam generator, a water-cooled reactor, and other multiphase processes can be subject to instabilities. It appears that the most predominant instabilities are the so-called density-wave oscillations. They can cause difficulties for three main reasons; they may induce burnout; they may cause mechanical vibrations of components; and they create system control problems. A comprehensive review is presented of experimental and theoretical studies concerning density-wave oscillations. (author)

An experiment using neutron activation analysis and a rare earth element to mark cotton plants and two insects that feed on them

Energy Technology Data Exchange (ETDEWEB)

Showler, Allan T. [USDA-ARS IFNRRU, Kika de la Garza Subtropical Agricultural Research Center, 2413 East Highway 83, Weslaco, TX 78596 (United States)]. E-mail: ashowler@weslaco.ars.usda.gov; James, William D. [Elemental Analysis Laboratory, 3144 Texas A and M University, College Station, TX 77843-3144 (United States); Armstrong, John S. [USDA-ARS BIRU, Kika de la Garza Subtropical Agricultural Research Center, 2413 East Highway 83, Weslaco, TX 78596 (United States); Westbrook, John K. [USDA-ARS APMRU, 2771 F and B Road, College Station, TX 77845-4966 (United States)

2006-08-15

Studies on insect dispersal and other behaviors can benefit from using markers that will not alter flight and fitness. Rare earth elements, such as samarium (Sm), have been used as ingested markers of some insects and detected using neutron activation analysis (NAA). In this study, samarium nitrate hexahydrate was mixed into artificial diet for boll weevils, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), at different dosages and in water used to irrigate cotton, Gossypium hirsutum L. Samarium was detected in adult boll weevils fed on the samarium-labeled diet, but not after 5 or 10 days of being switched to non-labeled diet, even if the insects were given labeled diet for as long as 7 consecutive days. Introduced in irrigation water, 1% samarium (m/m) was detectable in cotton squares and leaf tissue. However, boll weevil adults fed samarium-labeled squares did not retain detectable levels of samarium, nor did boll weevil adults reared to adulthood from samarium-labeled squares. Fourth instar beet armyworms, Spodoptera exigua (Huebner) (Noctuidae: Lepidoptera), fed on samarium-labeled cotton leaves obtained enough samarium for NAA detection, but adult moths reared from them did not have detectable amounts of samarium. Although samarium can be useful as a marker when insects are presented with a continuous pulse of the label, elements that are assimilated by the insect would be more useful if a continuous infusion of the marker cannot be provided.

Isotropic oscillator: spheroidal wave functions

International Nuclear Information System (INIS)

Mardoyan, L.G.; Pogosyan, G.S.; Ter-Antonyan, V.M.; Sisakyan, A.N.

1985-01-01

Solutions of the Schroedinger equation are found for an isotropic oscillator (10) in prolate and oblate spheroidal coordinates. It is shown that the obtained solutions turn into spherical and cylindrical bases of the isotropic oscillator at R→0 and R→ infinity (R is the dimensional parameter entering into the definition of prolate and oblate spheroidal coordinates). The explicit form is given for both prolate and oblate basis of the isotropic oscillator for the lowest quantum states

Chaotic solar oscillations

Energy Technology Data Exchange (ETDEWEB)

Blacher, S; Perdang, J [Institut d' Astrophysique, B-4200 Cointe-Ougree (Belgium)

1981-09-01

A numerical experiment on Hamiltonian oscillations demonstrates the existence of chaotic motions which satisfy the property of phase coherence. It is observed that the low-frequency end of the power spectrum of such motions is remarkably similar in structure to the low-frequency SCLERA spectra. Since the smallness of the observed solar amplitudes is not a sufficient mathematical ground for inefficiency of non-linear effects the possibility of chaos among solar oscillations cannot be discarded a priori.

On the nonlinear modeling of ring oscillators

KAUST Repository

Elwakil, Ahmed S.

2009-06-01

We develop higher-order nonlinear models of three-stage and five-stage ring oscillators based on a novel inverter model. The oscillation condition and oscillation frequency are derived and compared to classical linear model analysis. Two important special cases for five-stage ring oscillators are also studied. Numerical simulations are shown. © 2009 World Scientific Publishing Company.

On the nonlinear modeling of ring oscillators

KAUST Repository

Elwakil, Ahmed S.; Salama, Khaled N.

2009-01-01

We develop higher-order nonlinear models of three-stage and five-stage ring oscillators based on a novel inverter model. The oscillation condition and oscillation frequency are derived and compared to classical linear model analysis. Two important special cases for five-stage ring oscillators are also studied. Numerical simulations are shown. © 2009 World Scientific Publishing Company.

Synchronization of hyperchaotic oscillators

DEFF Research Database (Denmark)

Tamasevicius, A.; Cenys, A.; Mykolaitis, G.

1997-01-01

Synchronization of chaotic oscillators is believed to have promising applications in secure communications. Hyperchaotic systems with multiple positive Lyapunov exponents (LEs) have an advantage over common chaotic systems with only one positive LE. Three different types of hyperchaotic electronic...... oscillators are investigated demonstrating synchronization by means of only one properly selected variable....

Fabrication and properties of samarium doped calcium sulphate thin films using spray pyrolysis technique

Energy Technology Data Exchange (ETDEWEB)

Reghima, Meriem [Université Tunis El Manar, Faculté des Sciences de Tunis, Département de Physique, LR99ES13 Laboratoire de Physique de la Matière Condensée (LPMC), 2092 Tunis, Tunisie (Tunisia); Institut d' Electronique et des systèmes, Unité Mixte de Recherche 5214 UM2-CNRS (ST2i) – Université Montpellier, 860 rue de Saint Priest, Bâtiment 5, 34097 Montpellier (France); Faculté des Sciences de Bizerte, Université de Carthage, Zarzouna 7021 (Tunisia); Guasch, Cathy [Institut d' Electronique et des systèmes, Unité Mixte de Recherche 5214 UM2-CNRS (ST2i) – Université Montpellier, 860 rue de Saint Priest, Bâtiment 5, 34097 Montpellier (France); Azzaza, Sonia; Alleg, Safia [Laboratoire de Magnétisme et Spectroscopie des Solides (LM2S), Département de Physique, Faculté des Sciences, Université Badji Mokhtar Annaba, B.P. 12, 23000 Annaba (Algeria); Kamoun-Turki, Najoua [Université Tunis El Manar, Faculté des Sciences de Tunis, Département de Physique, LR99ES13 Laboratoire de Physique de la Matière Condensée (LPMC), 2092 Tunis, Tunisie (Tunisia)

2016-10-01

Using low cost spray pyrolysis technique, polycrystalline CaSO{sub 4} thin films were successfully grown on a glass substrate with a thickness of about 1 μm. Samarium doping has been performed on CaSO{sub 4} thin films to explore luminescence properties. The characterizations of these films were carried out using X-ray diffraction, Scanning Electron Microscopy and optical measurements. The structural analyses reveal the existence of hexagonal CaSO{sub 4} phase with a (200) preferred orientation belonging to CaS compound for substrate temperatures below 350 °C. It is shown that the crystallinity of the sprayed thin films can be improved by increasing substrate temperature up to 250 °C. Warren-Averbach analysis has been applied on X-ray diffractogram to determine structural parameters involving the phase with its amount, the grain size and the lattice parameters using Maud software. The surface topography shows a rough surface covered by densely packed agglomerated clusters having faceted and hexagonal shapes. Energy dispersive microscopy measurements confirm the presence of calcium and sulfur in equal proportions as well as high percentage of oxygen. Photoluminescence at room temperature revealed that luminescence peaks are attributed to the intrinsic emission of pure CaSO{sub 4} phase. - Highlights: • Warren Averbach analysis reveal the presence of hcp structure of CaSO{sub 4} phase. • A mixture of CaSO{sub 4} and CaHO{sub 4.5}S phases has been detected for lower T{sub s}. • For increasing T{sub s}, the CaHO{sub 4.5}S phase has been disappeared. • The origin of PL peaks has been identified.

Samarium oxide as a radiotracer to evaluate the in vivo biodistribution of PLGA nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Mandiwana, Vusani, E-mail: VMandiwana@csir.co.za; Kalombo, Lonji, E-mail: LKalombo@csir.co.za [Centre of Polymers and Composites, CSIR (South Africa); Venter, Kobus, E-mail: Kobus.Venter@mrc.ac.za [South African Medical Research Council (South Africa); Sathekge, Mike, E-mail: Mike.Sathekge@up.ac.za [University of Pretoria and Steve Biko Academic Hospital, Department of Nuclear Medicine (South Africa); Grobler, Anne, E-mail: Anne.Grobler@nwu.ac.za; Zeevaart, Jan Rijn, E-mail: zeevaart@necsa.co.za [North-West University, DST/NWU Preclinical Drug Development Platform (South Africa)

2015-09-15

Developing nanoparticulate delivery systems that will allow easy movement and localization of a drug to the target tissue and provide more controlled release of the drug in vivo is a challenge in nanomedicine. The aim of this study was to evaluate the biodistribution of poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles containing samarium-153 oxide ([{sup 153}Sm]Sm{sub 2}O{sub 3}) in vivo to prove that orally administered nanoparticles alter the biodistribution of a drug. These were then activated in a nuclear reactor to produce radioactive {sup 153}Sm-loaded-PLGA nanoparticles. The nanoparticles were characterized for size, zeta potential, and morphology. The nanoparticles were orally and intravenously (IV) administered to rats in order to trace their uptake through imaging and biodistribution studies. The {sup 153}Sm-loaded-PLGA nanoparticles had an average size of 281 ± 6.3 nm and a PDI average of 0.22. The zeta potential ranged between 5 and 20 mV. The [{sup 153}Sm]Sm{sub 2}O{sub 3} loaded PLGA nanoparticles, orally administered were distributed to most organs at low levels, indicating that there was absorption of nanoparticles. While the IV injected [{sup 153}Sm]Sm{sub 2}O{sub 3}-loaded PLGA nanoparticles exhibited the highest localization of nanoparticles in the spleen (8.63 %ID/g) and liver (3.07 %ID/g), confirming that nanoparticles are rapidly removed from the blood by the RES, leading to rapid uptake in the liver and spleen. From the biodistribution data obtained, it is clear that polymeric nanoscale delivery systems would be suitable for improving permeability and thus the bioavailability of therapeutic compounds.

Flashing oscillation in pool water

International Nuclear Information System (INIS)

Takamasa, Tomoji; Kondo, Koichi; Hazuku, Tatsuya

1996-01-01

This paper presents an experimental study of high-pressure saturated water discharging into the pool water. The purpose of the experiment is to clarify the phenomena that occur in blow-down of high-pressure saturated water from the pressure vessel into the water-filled containment in the case of a wall-crack accident or a LOCA in an advanced reactor. The results revealed that a flashing oscillation (FO) occurs when high-pressure saturated water discharges into the pool water, under specified experimental settings. The range of the flashing oscillates between a point very close to and some distance from the vent hole. The pressures in the vent tube and pool water vary according to the flashing oscillation. The pressure oscillation and frequency of flashing position might be caused by the balancing action between the supply of saturated water, flashing at the control volume and its condensation on the steam-water interface. A linear analysis was conducted using a spherical flashing bubble model. The period of the flashing oscillation in the experiments can be explained by theoretical analysis

New Realizations of Single OTRA-Based Sinusoidal Oscillators

Directory of Open Access Journals (Sweden)

Hung-Chun Chien

2014-01-01

Full Text Available This study proposes three new sinusoidal oscillators based on an operational transresistance amplifier (OTRA. Each of the proposed oscillator circuits consists of one OTRA combined with a few passive components. The first circuit is an OTRA-based minimum RC oscillator. The second circuit is capable of providing independent control on the condition of oscillation without affecting the oscillation frequency. The third circuit exhibits independent control of oscillation frequency through a capacitor. This study first introduces the OTRA and the related formulations of the proposed oscillator circuits, and then discusses the nonideal effects, sensitivity analyses, and frequency stability of the presented circuits. The proposed oscillators exhibit low sensitivities and good frequency stability. Because the presented circuits feature low impedance output, they can be connected directly to the next stage without cascading additional voltage buffers. HSPICE simulations and experimental results confirm the feasibility of the new oscillator circuits.

Neutrino oscillations: present status and outlook

International Nuclear Information System (INIS)

Schwetz, T.

2005-01-01

In this talk the present status of neutrino oscillations is reviewed, based on a global analysis of world neutrino oscillation data from solar, atmospheric, reactor, and accelerator neutrino experiments. Furthermore, I discuss the expected improvements in the determination of neutrino parameters by future oscillation experiments within a timescale of 10 years. (author)

Neutrino oscillations in the early universe

International Nuclear Information System (INIS)

Enqvist, K.

1990-01-01

The oscillations of electron neutrinos into inert neutrinos may have resonant behaviour in the heat bath of the early Universe. It is shown that any initial neutrino asymmetry will be washed away by the oscillations. Neutrino oscillations would affect also primordial helium production, which implies stringent limits on the neutrino mixing parameters. (orig.)

Coding of Information in Limit Cycle Oscillators

Science.gov (United States)

Schleimer, Jan-Hendrik; Stemmler, Martin

2009-12-01

Starting from a general description of noisy limit cycle oscillators, we derive from the Fokker-Planck equations the linear response of the instantaneous oscillator frequency to a time-varying external force. We consider the time series of zero crossings of the oscillator’s phase and compute the mutual information between it and the driving force. A direct link is established between the phase response curve summarizing the oscillator dynamics and the ability of a limit cycle oscillator, such as a heart cell or neuron, to encode information in the timing of peaks in the oscillation.

Oscillations in neutron stars

Energy Technology Data Exchange (ETDEWEB)

Hoeye, Gudrun Kristine

1999-07-01

We have studied radial and nonradial oscillations in neutron stars, both in a general relativistic and non-relativistic frame, for several different equilibrium models. Different equations of state were combined, and our results show that it is possible to distinguish between the models based on their oscillation periods. We have particularly focused on the p-, f-, and g-modes. We find oscillation periods of II approx. 0.1 ms for the p-modes, II approx. 0.1 - 0.8 ms for the f-modes and II approx. 10 - 400 ms for the g-modes. For high-order (l (>{sub )} 4) f-modes we were also able to derive a formula that determines II{sub l+1} from II{sub l} and II{sub l-1} to an accuracy of 0.1%. Further, for the radial f-mode we find that the oscillation period goes to infinity as the maximum mass of the star is approached. Both p-, f-, and g-modes are sensitive to changes in the central baryon number density n{sub c}, while the g-modes are also sensitive to variations in the surface temperature. The g-modes are concentrated in the surface layer, while p- and f-modes can be found in all parts of the star. The effects of general relativity were studied, and we find that these are important at high central baryon number densities, especially for the p- and f-modes. General relativistic effects can therefore not be neglected when studying oscillations in neutron stars. We have further developed an improved Cowling approximation in the non-relativistic frame, which eliminates about half of the gap in the oscillation periods that results from use of the ordinary Cowling approximation. We suggest to develop an improved Cowling approximation also in the general relativistic frame. (Author)

Oscillations in neutron stars

International Nuclear Information System (INIS)

Hoeye, Gudrun Kristine

1999-01-01

We have studied radial and nonradial oscillations in neutron stars, both in a general relativistic and non-relativistic frame, for several different equilibrium models. Different equations of state were combined, and our results show that it is possible to distinguish between the models based on their oscillation periods. We have particularly focused on the p-, f-, and g-modes. We find oscillation periods of II approx. 0.1 ms for the p-modes, II approx. 0.1 - 0.8 ms for the f-modes and II approx. 10 - 400 ms for the g-modes. For high-order (l → 4) f-modes we were also able to derive a formula that determines II l+1 from II l and II l-1 to an accuracy of 0.1%. Further, for the radial f-mode we find that the oscillation period goes to infinity as the maximum mass of the star is approached. Both p-, f-, and g-modes are sensitive to changes in the central baryon number density n c , while the g-modes are also sensitive to variations in the surface temperature. The g-modes are concentrated in the surface layer, while p- and f-modes can be found in all parts of the star. The effects of general relativity were studied, and we find that these are important at high central baryon number densities, especially for the p- and f-modes. General relativistic effects can therefore not be neglected when studying oscillations in neutron stars. We have further developed an improved Cowling approximation in the non-relativistic frame, which eliminates about half of the gap in the oscillation periods that results from use of the ordinary Cowling approximation. We suggest to develop an improved Cowling approximation also in the general relativistic frame. (Author)

Atmospheric neutrino oscillations for earth tomography

International Nuclear Information System (INIS)

Winter, Walter

2016-01-01

Modern proposed atmospheric neutrino oscillation experiments, such as PINGU in the Antarctic ice or ORCA in Mediterranean sea water, aim for precision measurements of the oscillation parameters including the ordering of the neutrino masses. They can, however, go far beyond that: Since neutrino oscillations are affected by the coherent forward scattering with matter, neutrinos can provide a new view on the interior of the earth. We show that the proposed atmospheric oscillation experiments can measure the lower mantle density of the earth with a precision at the level of a few percent, including the uncertainties of the oscillation parameters and correlations among different density layers. While the earth's core is, in principle, accessible by the angular resolution, new technology would be required to extract degeneracy-free information.

Nonlinearity in oscillating bridges

Directory of Open Access Journals (Sweden)

Filippo Gazzola

2013-09-01

Full Text Available We first recall several historical oscillating bridges that, in some cases, led to collapses. Some of them are quite recent and show that, nowadays, oscillations in suspension bridges are not yet well understood. Next, we survey some attempts to model bridges with differential equations. Although these equations arise from quite different scientific communities, they display some common features. One of them, which we believe to be incorrect, is the acceptance of the linear Hooke law in elasticity. This law should be used only in presence of small deviations from equilibrium, a situation which does not occur in widely oscillating bridges. Then we discuss a couple of recent models whose solutions exhibit self-excited oscillations, the phenomenon visible in real bridges. This suggests a different point of view in modeling equations and gives a strong hint how to modify the existing models in order to obtain a reliable theory. The purpose of this paper is precisely to highlight the necessity of revisiting the classical models, to introduce reliable models, and to indicate the steps we believe necessary to reach this target.

Generalized model for Memristor-based Wien family oscillators

KAUST Repository

Talukdar, Abdul Hafiz Ibne

2012-07-23

In this paper, we report the unconventional characteristics of Memristor in Wien oscillators. Generalized mathematical models are developed to analyze four members of the Wien family using Memristors. Sustained oscillation is reported for all types though oscillating resistance and time dependent poles are present. We have also proposed an analytical model to estimate the desired amplitude of oscillation before the oscillation starts. These Memristor-based oscillation results, presented for the first time, are in good agreement with simulation results. © 2011 Elsevier Ltd.

Fabrication of samarium strontium aluminate ceramic and deposition of thermal barrier coatings by air plasma spray process

Directory of Open Access Journals (Sweden)

Baskaran T

2018-01-01

Full Text Available Thermal barrier coatings (TBC with the metallic NiCrAlY bond coat are often used in many aircraft engines to protect superalloy components from high-temperature corrosion thereby to improve the life of gas turbine components. The search for new TBC material has been intensified in recent years due to lack of thermo-physical properties of conventionally used Yttria stabilized Zirconia (YSZ TBCs. Recently, the rare earth containing Samarium Strontium Aluminate (SSA based ceramic was proposed as a new TBC material due to its matching thermo-physical properties with the substrate. The present work focused on the synthesis of SSA ceramics for TBCs application and its coatings development on Ni-based superalloy Inconel 718 substrate by air plasma spray process. The X-ray photoelectron spectroscopy (XPS result confirmed the formation of single phase SSA ceramic after synthesis. The surface morphology of SSA TBCs is mainly composed of melted splats, semi and un-melted particles. The cross-sectional SEM micrographs did not show any spallation at the interface which indicated good mechanical interlocking between the bond coat and ceramic top coat. The Young’s modulus and hardness of SSA TBCs were found to be 80 and 6.1 GPa, respectively. The load-depth curve of SSA TBC showed good elastic recovery about 47 %.

Breaking of ensembles of linear and nonlinear oscillators

International Nuclear Information System (INIS)

Buts, V.A.

2016-01-01

Some results concerning the study of the dynamics of ensembles of linear and nonlinear oscillators are stated. It is shown that, in general, a stable ensemble of linear oscillator has a limited number of oscillators. This number has been defined for some simple models. It is shown that the features of the dynamics of linear oscillators can be used for conversion of the low-frequency energy oscillations into high frequency oscillations. The dynamics of coupled nonlinear oscillators in most cases is chaotic. For such a case, it is shown that the statistical characteristics (moments) of chaotic motion can significantly reduce potential barriers that keep the particles in the capture region

NOx Emission Reduction by Oscillating Combustion

Energy Technology Data Exchange (ETDEWEB)

None

2005-09-01

This project focuses on a new technology that reduces NOx emissions while increasing furnace efficiency for both air- and oxygen-fired furnaces. Oscillating combustion is a retrofit technology that involves the forced oscillation of the fuel flow rate to a furnace. These oscillations create successive, fuel-rich and fuel-lean zones within the furnace.

Harmonic oscillations, chaos and synchronization in systems consisting of Van der Pol oscillator coupled to a linear oscillator

International Nuclear Information System (INIS)

Woafo, P.

1999-12-01

This paper deals with the dynamics of a model describing systems consisting of the classical Van der Pol oscillator coupled gyroscopically to a linear oscillator. Both the forced and autonomous cases are considered. Harmonic response is investigated along with its stability boundaries. Condition for quenching phenomena in the autonomous case is derived. Neimark bifurcation is observed and it is found that our model shows period doubling and period-m sudden transitions to chaos. Synchronization of two and more systems in their chaotic regime is presented. (author)

Low-frequency oscillations in radiative-convective models

Energy Technology Data Exchange (ETDEWEB)

Hu, Qi; Randall, D.A.

1991-12-31

Although eastward propagation is usually regarded as an essential feature of the low-frequency ``Madden-Julian oscillation`` observed in the tropical atmosphere, many observations indicate that there is an important stationary or quasi-stationary component of the oscillation. Yasunari (1979), for example, investigated the stationary 30--60 day variation in upper tropospheric cloudiness in the Asian summer monsoon region. In a case study of the 30--60 day oscillation. Hsu et al. (1990) found a strong stationary oscillation of the divergence, outgoing longwave mdiadon and other fields. A recent observational study by Weickmann and Khalsa (1990) offers further evidence that the Madden-Julian oscillation has an important stationary component. In this paper, we present evidence that intraseasonal oscillations can be produced by local radiative and convective processes. This suggests that the observed propagating Madden-Julian wave is produced by interactions between these local processes and the large scale motion field, and is not essential for the existence of the observed oscillation.

Low-frequency oscillations in radiative-convective models

Energy Technology Data Exchange (ETDEWEB)

Hu, Qi; Randall, D.A.

1991-01-01

Although eastward propagation is usually regarded as an essential feature of the low-frequency Madden-Julian oscillation'' observed in the tropical atmosphere, many observations indicate that there is an important stationary or quasi-stationary component of the oscillation. Yasunari (1979), for example, investigated the stationary 30--60 day variation in upper tropospheric cloudiness in the Asian summer monsoon region. In a case study of the 30--60 day oscillation. Hsu et al. (1990) found a strong stationary oscillation of the divergence, outgoing longwave mdiadon and other fields. A recent observational study by Weickmann and Khalsa (1990) offers further evidence that the Madden-Julian oscillation has an important stationary component. In this paper, we present evidence that intraseasonal oscillations can be produced by local radiative and convective processes. This suggests that the observed propagating Madden-Julian wave is produced by interactions between these local processes and the large scale motion field, and is not essential for the existence of the observed oscillation.

Oscillating nonlinear acoustic shock waves

DEFF Research Database (Denmark)

Gaididei, Yuri; Rasmussen, Anders Rønne; Christiansen, Peter Leth

2016-01-01

We investigate oscillating shock waves in a tube using a higher order weakly nonlinear acoustic model. The model includes thermoviscous effects and is non isentropic. The oscillating shock waves are generated at one end of the tube by a sinusoidal driver. Numerical simulations show that at resona......We investigate oscillating shock waves in a tube using a higher order weakly nonlinear acoustic model. The model includes thermoviscous effects and is non isentropic. The oscillating shock waves are generated at one end of the tube by a sinusoidal driver. Numerical simulations show...... polynomial in the space and time variables, we find analytical approximations to the observed single shock waves in an infinitely long tube. Using perturbation theory for the driven acoustic system approximative analytical solutions for the off resonant case are determined....

A novel optogenetically tunable frequency modulating oscillator.

Directory of Open Access Journals (Sweden)

Tarun Mahajan

Full Text Available Synthetic biology has enabled the creation of biological reconfigurable circuits, which perform multiple functions monopolizing a single biological machine; Such a system can switch between different behaviours in response to environmental cues. Previous work has demonstrated switchable dynamical behaviour employing reconfigurable logic gate genetic networks. Here we describe a computational framework for reconfigurable circuits in E.coli using combinations of logic gates, and also propose the biological implementation. The proposed system is an oscillator that can exhibit tunability of frequency and amplitude of oscillations. Further, the frequency of operation can be changed optogenetically. Insilico analysis revealed that two-component light systems, in response to light within a frequency range, can be used for modulating the frequency of the oscillator or stopping the oscillations altogether. Computational modelling reveals that mixing two colonies of E.coli oscillating at different frequencies generates spatial beat patterns. Further, we show that these oscillations more robustly respond to input perturbations compared to the base oscillator, to which the proposed oscillator is a modification. Compared to the base oscillator, the proposed system shows faster synchronization in a colony of cells for a larger region of the parameter space. Additionally, the proposed oscillator also exhibits lesser synchronization error in the transient period after input perturbations. This provides a strong basis for the construction of synthetic reconfigurable circuits in bacteria and other organisms, which can be scaled up to perform functions in the field of time dependent drug delivery with tunable dosages, and sets the stage for further development of circuits with synchronized population level behaviour.

Separation control with fluidic oscillators in water

Science.gov (United States)

Schmidt, H.-J.; Woszidlo, R.; Nayeri, C. N.; Paschereit, C. O.

2017-08-01

The present study assesses the applicability of fluidic oscillators for separation control in water. The first part of this work evaluates the properties of the fluidic oscillators including frequency, cavitation effects, and exerted thrust. Derived from the governing internal dynamics, the oscillation frequency is found to scale directly with the jet's exit velocity and the size of the fluidic oscillator independent of the working fluid. Frequency data from various experiments collapse onto a single curve. The occurrence of cavitation is examined by visual inspection and hydrophone measurements. The oscillation frequency is not affected by cavitation because it does not occur inside the oscillators. The spectral information obtained with the hydrophone provide a reliable indicator for the onset of cavitation at the exit. The performance of the fluidic oscillators for separation control on a bluff body does not seem to be affected by the presence of cavitation. The thrust exerted by an array of fluidic oscillators with water as the working fluid is measured to be even larger than theoretically estimated values. The second part of the presented work compares the performance of fluidic oscillators for separation control in water with previous results in air. The array of fluidic oscillators is installed into the rear end of a bluff body model. The drag improvements based on force balance measurements agree well with previous wind tunnel experiments on the same model. The flow field is examined by pressure measurements and with particle image velocimetry. Similar performance and flow field characteristics are observed in both water and air.

Circuit oscillations in odor perception and memory.

Science.gov (United States)

Kay, Leslie M

2014-01-01

Olfactory system neural oscillations as seen in the local field potential have been studied for many decades. Recent research has shown that there is a functional role for the most studied gamma oscillations (40-100Hz in rats and mice, and 20Hz in insects), without which fine odor discrimination is poor. When these oscillations are increased artificially, fine discrimination is increased, and when rats learn difficult and highly overlapping odor discriminations, gamma is increased in power. Because of the depth of study on this oscillation, it is possible to point to specific changes in neural firing patterns as represented by the increase in gamma oscillation amplitude. However, we know far less about the mechanisms governing beta oscillations (15-30Hz in rats and mice), which are best associated with associative learning of responses to odor stimuli. These oscillations engage every part of the olfactory system that has so far been tested, plus the hippocampus, and the beta oscillation frequency band is the one that is most reliably coherent with other regions during odor processing. Respiratory oscillations overlapping with the theta frequency band (2-12Hz) are associated with odor sniffing and normal breathing in rats. They also show coupling in some circumstances between olfactory areas and rare coupling between the hippocampus and olfactory bulb. The latter occur in specific learning conditions in which coherence strength is negatively or positively correlated with performance, depending on the task. There is still much to learn about the role of neural oscillations in learning and memory, but techniques that have been brought to bear on gamma oscillations (current source density, computational modeling, slice physiology, behavioral studies) should deliver much needed knowledge of these events. © 2014 Elsevier B.V. All rights reserved.

Quantum oscillations of conductivity in bismuth wires

International Nuclear Information System (INIS)

Condrea, Elena

2011-01-01

Measurements of the resistance of bismuth nanowires with several diameters and different quality reveal oscillations on the dependence of resistance under uniaxial strain at T = 4.2 K. Amplitude of oscillations is significant (38 %) at helium temperature and becomes smearing at T = 77 K. Observed oscillations originate from quantum size effect. A simple evaluation of period of oscillations allows us to identify the groups of carriers involved in transport. Calculated periods of 42.2 and 25.9 nm satisfy approximately the ratio 2:1 for two experimentally observed sets of oscillations from light and heavy electrons.

Theory of a quantum anharmonic oscillator

International Nuclear Information System (INIS)

Carusotto, S.

1988-01-01

The time evolution of a quantum single-quartic anharmonic oscillator is considered. The study is carried on in operational form by use of the raising and lowering operators of the oscillator. The equation of motion is solved by application of a new integration method based on iteration techniques, and the rigorous solutions that describe the time development of the displacement and momentum operators of the oscillator are obtained. These operators are presented as a Laplace transform and a subsequent inverse Laplace transform of suitable functionals. Finally, the results are employed to describe the time evolution of a quasiclassical anharmonic oscillator

Symmetries and symmetry-breaking in oscillator ensembles

International Nuclear Information System (INIS)

Ujjwal, Sangeeta R.; Ramaswamy, Ram

2017-01-01

The behaviour of collections of oscillators has also been of interest for at least a few centuries as well. As it happens, Huygens described the interaction of two pendulums that resulted in their synchrony, namely the entrainment of one oscillator by the other. He gave a fairly accurate physical explanation for the process, namely that the pendulums oscillated in 'sympathy', adjusting their rhythms as a consequence of the weak coupling between them. The study of synchrony has thus been of interest since long, given the wide variety of systems that show 'sync'. These range from simple mechanical oscillators such as pendulums, to chemical and biological oscillators, coupled Josephson junctions and so on. In short, any system that is capable of showing sustained oscillations is also potentially able to synchronise

Reactor Neutrino Oscillations: KamLAND and KASKA

International Nuclear Information System (INIS)

Suekane, F.

2006-01-01

Nuclear reactors generate a huge number of low energy ν-bar e 's. The reactor neutrinos have been used to study properties of neutrinos since its discovery a half century ago. Recently, KamLAND group finally discovered reactor neutrino oscillation with average baseline 180 km. According to the 3 flavor scheme of standard theory and measured oscillation parameters so far, the reactor neutrino is expected to perform another type of small oscillation at a baseline 1.8 km. KASKA experiment is a project to detect this small oscillation and to measure the last neutrino mixing angle θ 13 by using the world most powerful reactor complex, Kashiwazaki-Kariwa nuclear power station. In this proceedings, phenomena of neutrino oscillation and the two reactor oscillation experiments, KamLAND and KASKA, are introduced

Ka Band Phase Locked Loop Oscillator Dielectric Resonator Oscillator for Satellite EHF Band Receiver

Directory of Open Access Journals (Sweden)

S. Coco

2008-01-01

Full Text Available This paper describes the design and fabrication of a Ka Band PLL DRO having a fundamental oscillation frequency of 19.250 GHz, used as local oscillator in the low-noise block of a down converter (LNB for an EHF band receiver. Apposite circuital models have been created to describe the behaviour of the dielectric resonator and of the active component used in the oscillator core. The DRO characterization and measurements have shown very good agreement with simulation results. A good phase noise performance is obtained by using a very high Q dielectric resonator.

State space modeling of Memristor-based Wien oscillator

KAUST Repository

Talukdar, Abdul Hafiz Ibne; Radwan, Ahmed G.; Salama, Khaled N.

2011-01-01

State space modeling of Memristor based Wien 'A' oscillator has been demonstrated for the first time considering nonlinear ion drift in Memristor. Time dependant oscillating resistance of Memristor is reported in both state space solution and SPICE simulation which plausibly provide the basis of realizing parametric oscillation by Memristor based Wien oscillator. In addition to this part Memristor is shown to stabilize the final oscillation amplitude by means of its nonlinear dynamic resistance which hints for eliminating diode in the feedback network of conventional Wien oscillator. © 2011 IEEE.

State space modeling of Memristor-based Wien oscillator

KAUST Repository

Talukdar, Abdul Hafiz Ibne

2011-12-01

State space modeling of Memristor based Wien \\'A\\' oscillator has been demonstrated for the first time considering nonlinear ion drift in Memristor. Time dependant oscillating resistance of Memristor is reported in both state space solution and SPICE simulation which plausibly provide the basis of realizing parametric oscillation by Memristor based Wien oscillator. In addition to this part Memristor is shown to stabilize the final oscillation amplitude by means of its nonlinear dynamic resistance which hints for eliminating diode in the feedback network of conventional Wien oscillator. © 2011 IEEE.

Two particle states, lepton mixing and oscillations

CERN Document Server

Kachelriess, M; Schönert, S

2000-01-01

Discussions of lepton mixing and oscillations consider generally only flavor oscillations of neutrinos and neglect the accompanying charged leptons. In cases of experimental interest like pion or nuclear beta decay an oscillation pattern is expected indeed only for neutrinos if only one of the two produced particles is observed. We argue that flavor oscillations of neutrinos without detecting the accompanying lepton is a peculiarity of the two-particle states $|l\

Optical oscillator-amplifier laser configuration

International Nuclear Information System (INIS)

McAllister, G.L.

1975-01-01

A laser is described that has incorporated therein an oscillator formed by a pair of mirrors, at least one of the mirrors being positioned outside of the envelope. The mirrors are dimensioned and spaced from each other so that the resonator has a relatively low Fresnel number and is operated unstably. The entire surface of one of these mirrors is convex and diffracts a portion of the energy outside of the oscillator region. Also incorporated into the laser is an amplifier region defined by a separate pair of mirrors which receive the energy diffracted from the oscillator region. The second pair of mirrors form an optical system with a high Fresnel number. A filter, modulator or other control for the laser signal may be placed outside the laser envelope in the optical path of the oscillator

Activity patterns in networks stabilized by background oscillations.

Science.gov (United States)

Hoppensteadt, Frank

2009-07-01

The brain operates in a highly oscillatory environment. We investigate here how such an oscillating background can create stable organized behavior in an array of neuro-oscillators that is not observable in the absence of oscillation, much like oscillating the support point of an inverted pendulum can stabilize its up position, which is unstable without the oscillation. We test this idea in an array of electronic circuits coming from neuroengineering: we show how the frequencies of the background oscillation create a partition of the state space into distinct basins of attraction. Thus, background signals can stabilize persistent activity that is otherwise not observable. This suggests that an image, represented as a stable firing pattern which is triggered by a voltage pulse and is sustained in synchrony or resonance with the background oscillation, can persist as a stable behavior long after the initial stimulus is removed. The background oscillations provide energy for organized behavior in the array, and these behaviors are categorized by the basins of attraction determined by the oscillation frequencies.

A Conspiracy of Oscillators

DEFF Research Database (Denmark)

Hjorth, Poul G.

2008-01-01

We discuss nonlinear mechanical systems containing several oscillators whose frequecies are all much higher than frequencies associated with the remaining degrees of freedom. In this situation a near constant of the motion, an adiabatic invariant, exists which is the sum of all the oscillator...... actions. The phenomenon is illustrated, and calculations of the small change of the adiabatic invariant is outlined....

Nanoconstriction spin-Hall oscillator with perpendicular magnetic anisotropy

Science.gov (United States)

Divinskiy, B.; Demidov, V. E.; Kozhanov, A.; Rinkevich, A. B.; Demokritov, S. O.; Urazhdin, S.

2017-07-01

We experimentally study spin-Hall nano-oscillators based on [Co/Ni] multilayers with perpendicular magnetic anisotropy. We show that these devices exhibit single-frequency auto-oscillations at current densities comparable to those for in-plane magnetized oscillators. The demonstrated oscillators exhibit large magnetization precession amplitudes, and their oscillation frequency is highly tunable by the electric current. These features make them promising for applications in high-speed integrated microwave circuits.

Multivariate Time Series Decomposition into Oscillation Components.

Science.gov (United States)

Matsuda, Takeru; Komaki, Fumiyasu

2017-08-01

Many time series are considered to be a superposition of several oscillation components. We have proposed a method for decomposing univariate time series into oscillation components and estimating their phases (Matsuda & Komaki, 2017 ). In this study, we extend that method to multivariate time series. We assume that several oscillators underlie the given multivariate time series and that each variable corresponds to a superposition of the projections of the oscillators. Thus, the oscillators superpose on each variable with amplitude and phase modulation. Based on this idea, we develop gaussian linear state-space models and use them to decompose the given multivariate time series. The model parameters are estimated from data using the empirical Bayes method, and the number of oscillators is determined using the Akaike information criterion. Therefore, the proposed method extracts underlying oscillators in a data-driven manner and enables investigation of phase dynamics in a given multivariate time series. Numerical results show the effectiveness of the proposed method. From monthly mean north-south sunspot number data, the proposed method reveals an interesting phase relationship.

Augmenting cognition by neuronal oscillations

NARCIS (Netherlands)

Horschig, J.M.; Zumer, J.; Bahramisharif, A.

2014-01-01

Cortical oscillations have been shown to represent fundamental functions of a working brain, e.g., communication, stimulus binding, error monitoring, and inhibition, and are directly linked to behavior. Recent studies intervening with these oscillations have demonstrated effective modulation of both

Experiments with elasto-plastic oscillator

DEFF Research Database (Denmark)

Randrup-thomsen, Søren; Ditlevsen, Ove Dalager

1996-01-01

Plastic displacements of a Gaussian white noise excited three degrees of freedom non-ideal elasto-plastic oscillator are measured in laboratory experiments and the plastic displacements are compared to computer simulated results for the corresponding ideal elasto-plastic oscillator. The comparative...

Experiments with elasto-plastic oscillator

DEFF Research Database (Denmark)

Randrup-Thomsen, S.; Ditlevsen, Ove Dalager

1999-01-01

Plastic displacements of a Gaussian white noise excited three degrees of freedom non-ideal elasto-plastic oscillator are measured in laboratory experiments and the plastic displacements are compared to computer simulated results for the corresponding ideal elasto-plastic oscillator. The comparative...

MEDIA PEMBELAJARAN ANALOG OSCILLATOR VIRTUAL LABOLATORY

Directory of Open Access Journals (Sweden)

Aji Widhi Wibowo

2016-01-01

Full Text Available The purpose of this research is to design and implement a Virtual Labolatory Materials Signal Processing Sub discussion 'Oscillator' Analog as Newspapers. Developers using the model Sutopo Ariesto Hadi (2003 as a method to produce the product. Consists of six stages: concept, design, material collecting, assembly, testing and distribution. This results in the development of Virtual media Labolatory with material 'Oscillator' with the results of 4 (four practicum digital oscillator, namely (1 Oscillator Wien Bridge, (2 Colpitts oscillator, (3 Oscillator Hartley and (4 astable multivibrator. Another result is that a user be jobsheet practicum. There are two types, namely: (1 jobsheet grip lecturers and (2 jobsheet for students. In Jobsheet there is a short book that contains the Manual on procedures for the use of virtual labolatory when practical and anatomical description of the product. Virtual Labolatory consists of the initial page (flash scren, the main page (home, pages and pages about the developer's lab referring to the story board. There are four (4 test are: (1 the truth polarity capacitor, (2 the connection (wiring, (3 mode frequency and time in the meter frequency

New neutrino oscillation results from NOVA

CERN Multimedia

CERN. Geneva

2018-01-01

Neutrinos oscillate among flavors as they travel because a neutrino of a particular flavor is also a superposition of multiple neutrinos with slightly different masses.  The interferometric nature of oscillations allows these tiny mass differences to be measured, along with the parameters of the PMNS matrix which governs the mixing. However, since neutrinos only interact weakly, a powerful neutrino source and massive detectors are required to measure them. In this talk I will show recently updated results from NOvA, a long-baseline neutrino oscillation experiment at Fermilab with two functionally identical scintillator detectors. I will present measurements of muon neutrino disappearance and electron neutrino appearance, and what constraints those measurements put on the remaining open questions in neutrino oscillations: Is the neutrino mass hierarchy "normal" or "inverted?" Do neutrino oscillations violate CP symmetry? Is the mixing in the atmospheric sector maximal? The recent update includes 50%...

Disturbed solution of the El Niño-southern oscillation sea—air delayed oscillator

International Nuclear Information System (INIS)

Xie Feng; Lin Wan-Tao; Lin Yi-Hua; Mo Jia-Qi

2011-01-01

A class of delayed oscillators of El Niño-southern oscillation (ENSO) models is considered. Using the delayed theory, the perturbed theory and other methods, the asymptotic expansions of the solutions for ENSO models are obtained and the asymptotic behaviour of solution of corresponding problem is studied. (general)

Voltage-driven quantum oscillations in graphene

International Nuclear Information System (INIS)

Yampol'skii, V A; Savel'ev, S; Nori, Franco

2008-01-01

We predict unusual (for non-relativistic quantum mechanics) electron states in graphene, which are localized within a finite-width potential barrier. The density of localized states in the sufficiently high and/or wide graphene barrier exhibits a number of singularities at certain values of the energy. Such singularities provide quantum oscillations of both the transport (e.g. conductivity) and thermodynamic properties of graphene-when increasing the barrier height and/or width, similarly to the well-known Shubnikov-de-Haas (SdH) oscillations of conductivity in pure metals. However, here the SdH-like oscillations are driven by an electric field instead of the usual magnetically driven SdH-oscillations

Brownian parametric oscillators

Science.gov (United States)

Zerbe, Christine; Jung, Peter; Hänggi, Peter

1994-05-01

We discuss the stochastic dynamics of dissipative, white-noise-driven Floquet oscillators, characterized by a time-periodic stiffness. Thus far, little attention has been paid to these exactly solvable nonstationary systems, although they carry a rich potential for several experimental applications. Here, we calculate and discuss the mean values and variances, as well as the correlation functions and the Floquet spectrum. As one main result, we find for certain parameter values that the fluctuations of the position coordinate are suppressed as compared to the equilibrium value of a harmonic oscillator (parametric squeezing).

Recent Progress in Silicon Mems Oscillators

Science.gov (United States)

2008-12-01

MEMS oscillator. As shown, a MEMS resonator is connected to an IC. The reference oscillator, which is basically a transimpedance amplifier ...small size), and (3) DC bias voltage required to operate the resonators. As a result, instead of Colpitts or Pierce architecture, a transimpedence ... amplifier is typically used for sustain the oscillation. The frequency of the resonators is determined by both material properties and geometry of

Chemical Oscillations

Indian Academy of Sciences (India)

IMTECH),. Chandigarh. Praveen Kumar is pursuing his PhD in chemical dynamics at. Panjab University,. Chandigarh. Keywords. Chemical oscillations, autoca-. talYSis, Lotka-Volterra model, bistability, hysteresis, Briggs-. Rauscher reaction.

Chemical Oscillations

Indian Academy of Sciences (India)

the law of mass-action that every simple reaction approaches ... from thermodynamic equilibrium. Such oscillating systems cor- respond to thermodynamically open systems. .... experimentally observable, and the third is always unstable.

The Duffing oscillator with damping

DEFF Research Database (Denmark)

Johannessen, Kim

2015-01-01

An analytical solution to the differential equation describing the Duffing oscillator with damping is presented. The damping term of the differential equation and the initial conditions satisfy an algebraic equation, and thus the solution is specific for this type of damping. The nonlinear term...... of the differential equation is allowed to be considerable compared to the linear term. The solution is expressed in terms of the Jacobi elliptic functions by including a parameter-dependent elliptic modulus. The analytical solution is compared to the numerical solution, and the agreement is found to be very good....... It is established that the period of oscillation is shorter compared to that of a linearized model but increasing with time and asymptotically approaching the period of oscillation of the linear damped model. An explicit expression for the period of oscillation has been derived, and it is found to be very accurate....

Transient voltage oscillations in coils

International Nuclear Information System (INIS)

Chowdhuri, P.

1985-01-01

Magnet coils may be excited into internal voltage oscillations by transient voltages. Such oscillations may electrically stress the magnet's dielectric components to many times its normal stress. This may precipitate a dielectric failure, and the attendant prolonged loss of service and costly repair work. Therefore, it is important to know the natural frequencies of oscillations of a magnet during the design stage, and to determine whether the expected switching transient voltages can excite the magnet into high-voltage internal oscillations. The series capacitance of a winding significantly affects its natural frequencies. However, the series capacitance is difficult to calculate, because it may comprise complex capacitance network, consisting of intra- and inter-coil turn-to-turn capacitances of the coil sections. A method of calculating the series capacitance of a winding is proposed. This method is rigorous but simple to execute. The time-varying transient voltages along the winding are also calculated

Electronically tunable RC sinusoidal oscillators

International Nuclear Information System (INIS)

Florescu, Valeriu

2008-01-01

This paper presents two types of active configurations for realizing electronically tunable RC sinusoidal oscillators. The type-1 network employs two grounded scaled resistances KR 1 and KR 2 , where K is scaling factor. The frequency of oscillation W 0 is controlled conveniently by adjusting K, since W 0 appears in the form W 0 =1/K √ R 1 C 1 R 2 C 2 . For realizing the scaled resistances, an active configuration is proposed, which realizes KR 1 =R 1 /(1+f(V B )), where f(V B ) denotes a function of a controlling voltage V B . Thus the frequency tuning can be effected by controlling a voltage V B . The type-2 oscillator uses two periodically switched conductances. It is shown that the tuning of oscillation frequency can be done by varying the pulse width-to-period ratio (t/T) of the periodically switched conductances. (author)

Oscillators and operational amplifiers

OpenAIRE

Lindberg, Erik

2005-01-01

A generalized approach to the design of oscillators using operational amplifiers as active elements is presented. A piecewise-linear model of the amplifier is used so that it make sense to investigate the eigenvalues of the Jacobian of the differential equations. The characteristic equation of the general circuit is derived. The dynamic nonlinear transfer characteristic of the amplifier is investigated. Examples of negative resistance oscillators are discussed.

Phase noise and frequency stability in oscillators

CERN Document Server

Rubiola, Enrico

2009-01-01

Presenting a comprehensive account of oscillator phase noise and frequency stability, this practical text is both mathematically rigorous and accessible. An in-depth treatment of the noise mechanism is given, describing the oscillator as a physical system, and showing that simple general laws govern the stability of a large variety of oscillators differing in technology and frequency range. Inevitably, special attention is given to amplifiers, resonators, delay lines, feedback, and flicker (1/f) noise. The reverse engineering of oscillators based on phase-noise spectra is also covered, and end-of-chapter exercises are given. Uniquely, numerous practical examples are presented, including case studies taken from laboratory prototypes and commercial oscillators, which allow the oscillator internal design to be understood by analyzing its phase-noise spectrum. Based on tutorials given by the author at the Jet Propulsion Laboratory, international IEEE meetings, and in industry, this is a useful reference for acade...

A family of memristor-based reactance-less oscillators

KAUST Repository

Zidan, Mohammed A.

2013-05-03

In this paper, we present for the first time a family of memristor-based reactance-less oscillators (MRLOs). The proposed oscillators require no reactive components, that is, inductors or capacitors, rather, the ‘resistance storage’ property of memristor is exploited to generate the oscillation. Different types of MRLO family are presented, and for each type, closed form expressions are derived for the oscillation condition, oscillation frequency, and range of oscillation. Derived equations are further verified using transient circuit simulations. A comparison between different MRLO types is also discussed. In addition, detailed fabrication steps of a memristor device and experimental results for the first MRLO physical realization are presented.

A family of memristor-based reactance-less oscillators

KAUST Repository

Zidan, Mohammed A.; Omran, Hesham; Smith, Casey; Syed, Ahad; Radwan, Ahmed Gomaa; Salama, Khaled N.

2013-01-01

In this paper, we present for the first time a family of memristor-based reactance-less oscillators (MRLOs). The proposed oscillators require no reactive components, that is, inductors or capacitors, rather, the ‘resistance storage’ property of memristor is exploited to generate the oscillation. Different types of MRLO family are presented, and for each type, closed form expressions are derived for the oscillation condition, oscillation frequency, and range of oscillation. Derived equations are further verified using transient circuit simulations. A comparison between different MRLO types is also discussed. In addition, detailed fabrication steps of a memristor device and experimental results for the first MRLO physical realization are presented.

Gamma oscillations: precise temporal coordination without a metronome.

Science.gov (United States)

Nikolić, Danko; Fries, Pascal; Singer, Wolf

2013-02-01

Gamma oscillations in the brain should not be conceptualized as a sine wave with constant oscillation frequency. Rather, these oscillations serve to concentrate neuronal discharges to particular phases of the oscillation cycle and thereby provide the substrate for various, functionally relevant synchronization phenomena. Copyright © 2012 Elsevier Ltd. All rights reserved.

Stochastic and Chaotic Relaxation Oscillations

NARCIS (Netherlands)

Grasman, J.; Roerdink, J.B.T.M.

1988-01-01

For relaxation oscillators stochastic and chaotic dynamics are investigated. The effect of random perturbations upon the period is computed. For an extended system with additional state variables chaotic behavior can be expected. As an example, the Van der Pol oscillator is changed into a

A Class-F CMOS Oscillator

NARCIS (Netherlands)

Babaie, M.; Staszewski, R.B.

2013-01-01

An oscillator topology demonstrating an improved phase noise performance is proposed in this paper. It exploits the time-variant phase noise model with insights into the phase noise conversion mechanisms. The proposed oscillator is based on enforcing a pseudo-square voltage waveform around the LC

The effectiveness of samarium-153 (153Sm) lexidronam (EDTMP) in treatment of bone metastases

International Nuclear Information System (INIS)

Ma Yubo; Huang Gang; Liu Jianjun

2004-01-01

Objectives: To evaluate the effectiveness of samarium-153 (153Sm) lexidronam (EDTMP) in treatment of bone metastases. Methods: 380 patients with bone metastases were studied (221 men, 159 women; average age 65.3 y; ranged 27-91 y; average weight 59.3 kg, ranged 39-95 kg). The tumor types were prostate carcinoma (n=155), pulmonary carcinoma (n=92), breast cancer (n=57), gastric carcinoma (n=12), colorectal carcinoma (n=22), nasopharyngeal carcinoma (n=8), lymphoma (n=8), hepatic carcinoma (n=6), ovary carcinoma (n=4) and others (n=16). All patients were received 135Sm-EDTMP 0.8 or 1.0 mCi/kg during 1 to 7 course of treatment. Patients and physician evaluations were used to assess pain relief. Numbers of metastatic foci and activity of ROIs were used to observe post-therapy change in bone scanning. Results: In 380 patients, pain relief was observed in 257 patients (67.6%). Persistence of pain relief was seen through 2 to 24 weeks. The mean relief time is 5.8±3.4 weeks. KPS score was higher 10% than pre-therapy (71.2%±9.6% Vs 80.9%±10.3%, p<0.001). Numbers of metastatic foci (11.2+8.8 Vs 8.4±5.7, p<0.001) and activity of ROIs (3.28±2.04 Vs 2.15±0.94, p<0.01) were less than pre-therapy. Bone marrow suppression was mild and reversible (5.87±1.56 Vs 4.94±1.16 x 109/L). Conclusions: 153Sm-EDTMP provided relief of pain associated with bone metastases and inhibition of metastatic foci. As a relief drug of painful bone metastases, 153Sm-EDTMP is safe and effective. (authors)

Neutrino Oscillations Physics

Science.gov (United States)

Fogli, Gianluigi

2005-06-01

We review the status of the neutrino oscillations physics, with a particular emphasis on the present knowledge of the neutrino mass-mixing parameters. We consider first the νμ → ντ flavor transitions of atmospheric neutrinos. It is found that standard oscillations provide the best description of the SK+K2K data, and that the associated mass-mixing parameters are determined at ±1σ (and NDF = 1) as: Δm2 = (2.6 ± 0.4) × 10-3 eV2 and sin 2 2θ = 1.00{ - 0.05}{ + 0.00} . Such indications, presently dominated by SK, could be strengthened by further K2K data. Then we point out that the recent data from the Sudbury Neutrino Observatory, together with other relevant measurements from solar and reactor neutrino experiments, in particular the KamLAND data, convincingly show that the flavor transitions of solar neutrinos are affected by Mikheyev-Smirnov-Wolfenstein (MSW) effects. Finally, we perform an updated analysis of two-family active oscillations of solar and reactor neutrinos in the standard MSW case.

Neutrino oscillations in the Kerr-Newman spacetime

International Nuclear Information System (INIS)

Ren Jun; Zhang Chengmin

2010-01-01

The mass neutrino oscillation in the Kerr-Newman (K-N) spacetime is studied in the plane θ = θ 0 , and general equations of the oscillation phases are given. The effect of the rotation and electric charge on the phase is presented. Then, we consider three special cases. (1) The neutrinos travel along the geodesics with angular momentum L = aE in the equatorial plane. (2) The neutrinos travel along the geodesics with L = 0 in the equatorial plane. (3) The neutrinos travel along the radial geodesics in the direction θ = 0. Finally, we calculate the proper oscillation length in the K-N spacetime. The effect of the gravitational field on the oscillation length is embodied in the gravitational red shift factor. When the neutrino travels out of the gravitational field, a blue shift of the oscillation length takes place. We discuss the variation of the oscillation length influenced by the gravitational field strength, the rotation a 2 and charge Q.

Oscillator strengths for neutral technetium

International Nuclear Information System (INIS)

Garstang, R.H.

1981-01-01

Oscillator strengths have been calculated for most of the spectral lines of TcI which are of interest in the study of stars of spectral type S. Oscillator strengths have been computed for the corresponding transitions in MnI as a partial check of the technetium calculations

Hyperchaos in coupled Colpitts oscillators

DEFF Research Database (Denmark)

Cenys, Antanas; Tamasevicius, Arunas; Baziliauskas, Antanas

2003-01-01

The paper suggests a simple solution of building a hyperchaotic oscillator. Two chaotic Colpitts oscillators, either identical or non-identical ones are coupled by means of two linear resistors R-k. The hyperchaotic output signal v(t) is a linear combination, specifically the mean of the individual...

Oscillations of neutral B mesons systems

CERN Document Server

Boucrot, J.

1999-01-01

The oscillation phenomenon in the neutral B mesons systems is now well established. The motivations and principles of the measurements are given; then the most recent results from the LEP experiments, the CDF collaboration at Fermilab and the SLD collaboration at SLAC are reviewed. The present world average of the $\\bd$ meson oscillation frequency is $\\dmd = 0.471 \\pm 0.016 \\ps$ and the lower limit on the $\\bs$ oscillation frequency is

Chimera States in Mechanical Oscillator Networks

OpenAIRE

Martens, Erik Andreas; Thutupalli, Shashi; Fourrière, Antoine; Hallatschek, Oskar

2013-01-01

The synchronization of coupled oscillators is a fascinating manifestation of self-organization that nature uses to orchestrate essential processes of life, such as the beating of the heart. Although it was long thought that synchrony and disorder were mutually exclusive steady states for a network of identical oscillators, numerous theoretical studies in recent years have revealed the intriguing possibility of “chimera states,” in which the symmetry of the oscillator population is broken into...

Introduction to classical and quantum harmonic oscillators

CERN Document Server

Bloch, Sylvan C

2013-01-01

From conch shells to lasers . harmonic oscillators, the timeless scientific phenomenon As intriguing to Galileo as they are to scientists today, harmonic oscillators have provided a simple and compelling paradigm for understanding the complexities that underlie some of nature's and mankind's most fascinating creations. From early string and wind instruments fashioned from bows and seashells to the intense precision of lasers, harmonic oscillators have existed in various forms, as objects of beauty and scientific use. And harmonic oscillation has endured as one of science's most fascinating con

Coherent states for oscillators of non-conventional statistics

International Nuclear Information System (INIS)

Dao Vong Duc; Nguyen Ba An

1998-12-01

In this work we consider systematically the concept of coherent states for oscillators of non-conventional statistics - parabose oscillator, infinite statistics oscillator and generalised q-deformed oscillator. The expressions for the quadrature variances and particle number distribution are derived and displayed graphically. The obtained results show drastic changes when going from one statistics to another. (author)

Determination of the speciation and bioavailability of samarium to Chlamydomonas reinhardtii in the presence of natural organic matter.

Science.gov (United States)

Rowell, Justine-Anne; Fillion, Marc-Alexandre; Smith, Scott; Wilkinson, Kevin J

2018-06-01

As technological interest and environmental emissions of the rare earth elements increase, it is becoming more important to assess their potential environmental impact. Samarium (Sm) is a lanthanide of intermediate molar mass that is used in numerous high-technology applications including wind turbines, solar panels, and electric vehicles. The present study relates the speciation of Sm determined in the presence of natural organic matter (NOM) to its bioavailability to the unicellular green alga Chlamydomonas reinhardtii. The free ion concentration was determined using a cation exchange resin (ion exchange technique) in dynamic mode and compared with thermodynamic modeling. Short-term biouptake experiments were performed in the presence of 4 types of NOM: Suwannee River fulvic acids, Pahokee Peat fulvic acids, Suwannee River humic acids, and a Luther Marsh dissolved organic matter isolate (90-95% humic acids). It was clearly shown that even a small amount of NOM (0.5 mg C L -1 ) resulted in a significant decrease (10 times) in the Sm internalization fluxes. Furthermore, complexation with humic acids (and the corresponding reduction in Sm bioavailability) was stronger than that with fulvic acids. The results showed that the experimentally measured (free) Sm was a better predictor of Sm internalization than either the total concentrations or the free ion concentrations obtained using thermodynamic modeling. Environ Toxicol Chem 2018;37:1623-1631. © 2018 SETAC. © 2018 SETAC.

Destructive impact of molecular noise on nanoscale electrochemical oscillators

Science.gov (United States)

Cosi, Filippo G.; Krischer, Katharina

2017-06-01

We study the loss of coherence of electrochemical oscillations on meso- and nanosized electrodes with numeric simulations of the electrochemical master equation for a prototypical electrochemical oscillator, the hydrogen peroxide reduction on Pt electrodes in the presence of halides. On nanoelectrodes, the electrode potential changes whenever a stochastic electron-transfer event takes place. Electrochemical reaction rate coefficients depend exponentially on the electrode potential and become thus fluctuating quantities as well. Therefore, also the transition rates between system states become time-dependent which constitutes a fundamental difference to purely chemical nanoscale oscillators. Three implications are demonstrated: (a) oscillations and steady states shift in phase space with decreasing system size, thereby also decreasing considerably the oscillating parameter regions; (b) the minimal number of molecules necessary to support correlated oscillations is more than 10 times as large as for nanoscale chemical oscillators; (c) the relation between correlation time and variance of the period of the oscillations predicted for chemical oscillators in the weak noise limit is only fulfilled in a very restricted parameter range for the electrochemical nano-oscillator.

Oscillating solitons in nonlinear optics

Indian Academy of Sciences (India)

... are derived, and the relevant properties and features of oscillating solitons are illustrated. Oscillating solitons are controlled by the reciprocal of the group velocity and Kerr nonlinearity. Results of this paper will be valuable to the study of dispersion-managed optical communication system and mode-locked fibre lasers.

Implementing a memristive Van der Pol oscillator coupled to a linear oscillator: synchronization and application to secure communication

International Nuclear Information System (INIS)

Megam Ngouonkadi, E B; Fotsin, H B; Louodop Fotso, P

2014-01-01

This paper investigates the dynamics of a memristor-based Van der Pol oscillator coupled to a linear circuit (VDPCL). This chaotic oscillator is a modification of the classical Van der Pol coupled to a linear circuit, and is obtained by replacing the classical cubic nonlinearity by the memristive one. The memristive VDPCL oscillator, in addition to having a very special stability property, exhibits interesting spectral characteristics, which makes it suitable for chaos-based secure communication applications. The memristor is realized by using off-the-shelf components. The basic properties of the circuit are analyzed by means of bifurcation analysis. Chaotic attractors from numerical and experimental analysis are presented, followed by a comparison of results obtained from the modified VDPCL oscillator and those from the classical VDPCL oscillator. An application to synchronization and chaos secure communication is also presented. (paper)

Oscillating thermionic conversion for high-density space power

International Nuclear Information System (INIS)

Jacobson, D.L.; Morris, J.F.

1988-01-01

The compactness, maneuverability, and productive weight utilization of space nuclear reactors benefit from the use of thermionic converters at high temperature. Nuclear-thermionic-conversion power requirements are discussed, and the role of oscillations in thermionic energy conversion (TEC) history is examined. Proposed TEC oscillations are addressed, and the results of recent studies of TEC oscillations are reviewed. The possible use of high-frequency TEC oscillations to amplify low-frequency ones is considered. The accomplishments of various programs studying the use of high-temperature thermionic oscillators are examined. 16 references

Samarium-153 Oksabifor in the treatment of metastatic bone disease

International Nuclear Information System (INIS)

Solodyannikova, O.; Voit, N.; Sukach, G.; Sagan, D.

2015-01-01

patients - reducing the number of foci and the level of radiopharmaceutical uptake in them. Conclusions: radionuclide therapy in patients with BM can effectively suppress pain and significantly reduce the number of analgesics. Post-treatment patients, life quality statistically significantly improved. Samarium-153 has the ability to reduce BM number and intensity of radiopharmaceutical accumulation in spots in the control study. (authors)

Anharmonic potential in the oscillator representation

International Nuclear Information System (INIS)

Dineykhan, M.; Efimov, G.V.

1994-01-01

In the non relativistic and relativized Schroedinger equation the Wick ordering method called the oscillator representation is proposed to calculate the energy spectrum for a wide class of potentials allowing the existence of a bound state. The oscillator representation method gives a unique regular way to describe and calculate the energy levels of ground as well as orbital and radial excitation states for a wide class of potentials. The results of the zeroth approximation oscillator representation are in good agreement with the exact values for the anharmonic potentials. The oscillator representation method was applied to the relativized Schroedinger equation too. The perturbation series converges fairly fast, i.e., the highest perturbation corrections over the interaction Hamiltonian are small enough. 29 refs.; 4 tabs. (author)

Waves and oscillations in nature an introduction

CERN Document Server

Narayanan, A Satya

2015-01-01

Waves and oscillations are found in large scales (galactic) and microscopic scales (neutrino) in nature. Their dynamics and behavior heavily depend on the type of medium through which they propagate.Waves and Oscillations in Nature: An Introduction clearly elucidates the dynamics and behavior of waves and oscillations in various mediums. It presents different types of waves and oscillations that can be observed and studied from macroscopic to microscopic scales. The book provides a thorough introduction for researchers and graduate students in assorted areas of physics, such as fluid dynamics,

Neutrino oscillation: status and outlooks

International Nuclear Information System (INIS)

Nedelec, P.

1994-01-01

Whether the neutrinos are massive or not is one of the most puzzling question of physics today. If they are massive, they can contribute significantly to the Dark Matter of the Universe. An other consequence of a non-zero mass of neutrinos is that they might oscillate from one flavor to another. This oscillation process is by now the only way to detect a neutrino with a mass in the few eV range. Several neutrino experiments are currently looking for such an oscillation, in different modes, using different techniques. An overview of the experimental situation for neutrino experiments at accelerators is given. (author). 9 refs., 5 figs., 5 tabs

Synchronous Oscillations in Microtubule Polymerization

Science.gov (United States)

Carlier, M. F.; Melki, R.; Pantaloni, D.; Hill, T. L.; Chen, Y.

1987-08-01

Under conditions where microtubule nucleation and growth are fast (i.e., high magnesium ion and tubulin concentrations and absence of glycerol), microtubule assembly in vitro exhibits an oscillatory regime preceding the establishment of steady state. The amplitude of the oscillations can represent >50% of the maximum turbidity change and oscillations persist for up to 20 periods of 80 s each. Oscillations are accompanied by extensive length redistribution of microtubules. Preliminary work suggests that the oscillatory kinetics can be simulated using a model in which many microtubules undergo synchronous transitions between growing and rapidly depolymerizing phases, complicated by the kinetically limiting rate of nucleotide exchange on free tubulin.

Again on neutrino oscillations

International Nuclear Information System (INIS)

Bilenky, S.M.; Pontecorvo, B.

1976-01-01

The general case is treated of a weak interaction theory in which a term violating lepton charges is present. In such a scheme the particles with definite masses are Majorana neutrinos (2N if in the weak interaction participate N four-component neutrinos). Neutrino oscillations are discussed and it is shown that the minimum average intensity at the earth of solar neutrinos is 1/2N of the intensity expected when oscillations are absent

Accelerator-based neutrino oscillation searches

International Nuclear Information System (INIS)

Whitehouse, D.; Rameika, G.

1993-01-01

This paper attempts to summarize the neutrino oscillation section of the Workshop on Future Directions in Particle and Nuclear Physics at Multi-GeV Hadron Beam Facilities. There were very lively discussions about the merits of the different oscillation channels, experiments, and facilities, but the authors believe a substantial consensus emerged

Sunspot Oscillations From The Chromosphere To The Corona

Science.gov (United States)

Brynildsen, N.; Maltby, P.; Fredvik, T.; Kjeldseth-Moe, O.

The behavior of the 3 minute sunspot oscillations is studied as a function of temper- ature through the transition region using observations with CDS/SOHO and TRACE. The oscillations occur above the umbra, with amplitudes increasing to a maximum near 200 000 K, then decreasing towards higher temperatures. Deviations from pure linear oscillations are present in several cases. Power spectra of the oscillations are remarkably similar in the chromosphere and through the transition region in contra- diction to the predictions of the sunspot filter theory. The 3 minute oscillations pene- trate to the low temperature end of the corona, where they are channeled into smaller areas coinciding with the endpoints of sunspot coronal loops. This differs from the transition zone where the oscillating region covers the umbra.

Fluorescence properties of europium and samarium. beta. -diketonates and their use in fluorometry

Energy Technology Data Exchange (ETDEWEB)

Huang, H; Hiraki, K; Nishikawa, Y [Kinki Univ., Higashi-Osaka, Osaka (Japan). Faculty of Science and Technology

1981-01-01

Several europium and samarium ..beta..-diketonates (tta, ntfa, bfa) complexed with 1, 10-phenanthroline, or with trioctylphosphine oxide (topo) were synthesized. The fluorescence properties of these compounds in benzene or hexane have been studied. Absorption and fluorescence spectra, fluorescence quantum yield, fluorescence sensitivity index (F.S.I.), and fluorescence lifetime were measured. From the measurement of fluorescence lifetime of the ..beta..-diketonates, the velocity of radiative process (k sub(f)/phi sub(f)) has almost the same value for benzene and hexane solvent. The red fluorescence (Em. max. : 619 nm) of Eu(III) in these chelates is attributed to transitions from /sup 5/D/sub 0/ ..-->.. /sup 7/F/sub 2/ levels of this ion, and the three-band spectrum (Em. max. : 569 nm, 606 nm, 650 nm) indicates the transitions from the /sup 4/G sub(5/2) ..-->.. /sup 6/H sub(5/2), /sup 4/G sub(5/2) ..-->.. /sup 6/H sub(7/2), and /sup 4/G sub(5/2) ..-->.. /sup 6/H sub(9/2) levels of Sm(III), respectively. These spectra are not changed by any solvents and ligands. From the results, the fluorescence of the ..beta..-diketonates in organic solvent has been attributed to m* ..-->.. m luminescence transition. The complexes of Eu(III) and Sm(III) show radiative transition within orbitals, composed exclusively of 4f orbitals of rare earth ions (m* ..-->.. m radiative transition). Fluorinated ligands show better sensitivity than unfluorinated ligands, and the best sensitivity is obtained with TTA-phen system, and/or TTA-topo system for the spectrofluorometric determination of the two metals. In the case of Eu determination, 619 nm emission wavelength is used (the determinable range : 0.2 -- 10 ppb Eu), and in the case of Sm determination, 650 nm emission wavelength is adopted (the determinable range : 0.1 -- 1 ppm Sm), because of much higher sensitivity than the other two peaks (569, 606 nm) without interference from europium complex.

The gamma oscillation: master or slave?

Science.gov (United States)

Schroeder, Charles E; Lakatos, Peter

2009-06-01

The idea that gamma enhancement reflects a state of high neuronal excitability and synchrony, critical for active brain operations, sets gamma up as a "master" or executor process that determines whether an input is effectively integrated and an effective output is generated. However, gamma amplitude is often coupled to the phase of lower frequency delta or theta oscillations, which would make gamma a "slave" to lower frequency activity. Gamma enslavement is productive and typical during rhythmic mode brain operations; when a predictable rhythm is in play, low and mid-frequency oscillations can be entrained and their excitability fluctuations of put to work in sensory and motor functions. When there is no task relevant rhythm that the system can entrain to, low frequency oscillations become detrimental to processing. Then, a continuous (vigilance) mode of operation is implemented; the system's sensitivity is maximized by suppressing lower frequency oscillations and exploiting continuous gamma band oscillations. Each mode has costs and benefits, and the brain shifts dynamically between them in accord with task demands.

Evaluation of thermal margin during BWR neutron flux oscillation

International Nuclear Information System (INIS)

Takeuchi, Yutaka; Takigawa, Yukio; Chuman, Kazuto; Ebata, Shigeo

1992-01-01

Fuel integrity is very important, from the view point of nuclear power plant safety. Recently, neutron flux oscillations were observed at several BWR plants. The present paper describes the evaluations of the thermal margin during BWR neutron flux oscillations, using a three-dimensional transient code. The thermal margin is evaluated as MCPR (minimum critical power ratio). The LaSalle-2 event was simulated and the MCPR during the event was evaluated. It was a core-wide oscillation, at which a large neutron flux oscillation amplitude was observed. The results indicate that the MCPR had a sufficient margin with regard to the design limit. A regional oscillation mode, which is different from a core-wide oscillation, was simulated and the MCPR response was compared with that for the LaSalle-2 event. The MCPR decrement is greater in the regional oscillation, than in the core wide -oscillation, because of the sensitivity difference in a flow-to-power gain. A study was carried out about regional oscillation detectability, from the MCPR response view point. Even in a hypothetically severe case, the regional oscillation is detectable by LPRM signals. (author)

Recent aspects of self-oscillating polymeric materials: designing self-oscillating polymers coupled with supramolecular chemistry and ionic liquid science.

Science.gov (United States)

Ueki, Takeshi; Yoshida, Ryo

2014-06-14

Herein, we summarise the recent developments in self-oscillating polymeric materials based on the concepts of supramolecular chemistry, where aggregates of molecular building blocks with non-covalent bonds evolve the temporal or spatiotemporal structure. By utilising the rhythmic oscillation of the association/dissociation of molecular aggregates coupled with the redox oscillation by the BZ reaction, novel soft materials that express similar functions as those of living matter will be achieved. Further, from the viewpoint of materials science, our recent approach to prepare self-oscillating materials that operate long-term under mild conditions will be introduced.

Search for νμ → νe oscillations

International Nuclear Information System (INIS)

Godley, A.R.

1998-01-01

Full text: Neutrino oscillations, the changing of neutrino flavour state from one of τ, μ or e, to another, are proof of massive neutrinos, in turn pointing to Physics beyond the Standard Model, and so are of great current interest. Solar and atmospheric neutrino results suggested evidence for neutrino oscillations. Further, a tau neutrino mass of ∼ 10 eV could supply the missing mass needed to close the Universe. To satisfy the increasing interest, CERN's Neutrino Physics Program commissioned two concurrent experiments to investigate the possibility of neutrino oscillations, one of which is NOMAD, Neutrino Oscillation Magnetic Detector. NOMAD was designed to verify or deny the earlier positive neutrino oscillations results by searching for muon to tauon neutrino oscillations in accelerator neutrinos. The LSND experiment later provided evidence for muon to electron neutrino oscillations, but due to the multi-purpose design of NOMAD, it was also possible to investigate this channel. Moreover, the area of phase space being uncovered, (related to neutrino energy and oscillation length), overlaps considerably with that of LSND. An electron neutrino oscillation search involves looking for electron neutrinos in what is primarily a muon neutrino beam, with just a small contamination of electron neutrinos. It is surmised that the excess of electron neutrinos come from oscillated muon neutrinos. This type of search is called an appearance search. The principles of such a search will be detailed herein. These include a breakdown of the CERN Neutrino Beam and a method for detecting and collating different neutrino flavours at NOMAD

Modified variational iteration method for an El Niño Southern Oscillation delayed oscillator

International Nuclear Information System (INIS)

Cao Xiao-Qun; Song Jun-Qiang; Zhu Xiao-Qian; Zhang Li-Lun; Zhang Wei-Min; Zhao Jun

2012-01-01

This paper studies a delayed air—sea coupled oscillator describing the physical mechanism of El Niño Southern Oscillation. The approximate expansions of the delayed differential equation's solution are obtained successfully by the modified variational iteration method. The numerical results illustrate the effectiveness and correctness of the method by comparing with the exact solution of the reduced model. (general)

Synchronization in Coupled Oscillators with Two Coexisting Attractors

International Nuclear Information System (INIS)

Han-Han, Zhu; Jun-Zhong, Yang

2008-01-01

Dynamics in coupled Duffing oscillators with two coexisting symmetrical attractors is investigated. For a pair of Duffing oscillators coupled linearly, the transition to the synchronization generally consists of two steps: Firstly, the two oscillators have to jump onto a same attractor, then they reach synchronization similarly to coupled monostable oscillators. The transition scenarios to the synchronization observed are strongly dependent on initial conditions. (general)

Electrostatically actuated oscillator of bundle and double-walled carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Kang, Jeong Won; Song, Ki Oh; Hwang, Ho Jung [Chung-Ang University, Seoul (Korea, Republic of); Lee, Jun Ha; Lee, Hoong Joo [Sangmyung University, Chonan (Korea, Republic of); Kwon, Oh Keun [Semyung University, Jecheon (Korea, Republic of); Yoon, Young Sik; Song, Young Jin [Konyang University, Nonsan (Korea, Republic of)

2006-03-15

Schematics of capacitively driven carbon nanotube (CNT) oscillators were presented and investigated by using classical molecular dynamics simulations. While the capacitive force acting on a CNT oscillator extruded it, the force exerted by the excess van der Waals energy sucked the CNT oscillator into the bundle or outer shell. The CNT oscillator could be oscillated by using both the Coulomb and the van der Waals interactions. The van der Waals force of the bundle-type CNT oscillator was less than the van der Waals force of the double-walled CNT oscillator. Molecular dynamics simulation results showed that double-walled CNT oscillators were better than bundle-type CNT oscillators in the aspects of both energy dissipation and stable operation.

Amplitude death and spatiotemporal bifurcations in nonlocally delay-coupled oscillators

International Nuclear Information System (INIS)

Guo, Yuxiao; Niu, Ben

2015-01-01

Amplitude death and spatiotemporal oscillations are remarkable patterns in coupled systems. We consider a ring of n identical oscillators with distance-dependent couplings and time delay. The amplitude death region is the intersection of three stable regions. Employing the method of multiple scales and normal form theory, the stability and criticality of spatiotemporal oscillations are determined. Around the amplitude death boundary there exist one branch of synchronized oscillations, n − 3 branches of co-existing phase-locked oscillations, n branches of mirror-reflecting oscillations, n branches of standing-wave oscillations, one branch of quasiperiodic oscillations and two branches of co-existing synchronized oscillations. It is proved that amplitude death is robust to small inhomogeneity of couplings, and the stability of synchronized or phase-locked oscillations inherits that of the individual decoupled oscillator. For the arbitrary form of coupling functions, some general results are also obtained for the thermodynamic limit. Finally, two examples are given to support the main results. (paper)

Modelling solar-like oscillators

Energy Technology Data Exchange (ETDEWEB)

Eggenberger, P; Miglio, A [Institut d' Astrophysique et de Geophysique de l' Universite de Liege, 17 Allee du 6 Aout, B-4000 Liege (Belgium); Carrier, F [Institute of Astronomy, University of Leuven, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Mathis, S [CEA/DSM/DAPNIA/Service d' Astrophysique, CEA/Saclay, AIM-Unite Mixte de Recherche CEA-CNRS-Universite Paris VII, UMR 7158, 91191 Gif-sur-Yvette Cedex (France)], E-mail: eggenberger@Qastro.ulg.ac.be

2008-10-15

The computation of models of stars for which solar-like oscillations have been observed is discussed. After a brief intoduction on the observations of solar-like oscillations, the modelling of isolated stars and of stars belonging to a binary system is presented with specific examples of recent theoretical calibrations. Finally the input physics introduced in stellar evolution codes for the computation of solar-type stars is discussed with a peculiar emphasis on the modelling of rotation for these stars.

A 65--70 year oscillation in observed surface temperatures

International Nuclear Information System (INIS)

Schlesinger, M.E.; Ramankutty, N.

1994-01-01

There are three possible sources for the 65--70-year ''global'' oscillation: (1) random forcing of the ocean by the atmosphere, such as by white noise; (2) external oscillatory forcing of the climate system, such as by a variation in the solar irradiance; and (3) an internal oscillation of the atmosphere-ocean system. It is unlikely that putative variations in solar irradiance are the source of the oscillation because solar forcing should generate a global response, but the oscillation is not global. It is also unlikely that white-noise forcing is the source of the oscillation because such forcing should generate an oceanwide response, but the oscillation is not panoceanic. Consequently, the most probable cause of the oscillation is an internal oscillation of the atmosphere-ocean system. This conclusion is supported by a growing body of observational evidence and coupled atmosphere/ocean general circulation model simulation results. Comparison of the regional and global-mean temperature changes caused by the oscillation with those induced by GHG + ASA forcing shows that the rapid rise in global-mean temperature between about 1908 and 1946, and the subsequent reversal of this warming until about 1965 were the result of the oscillation. In the North Atlantic and North American regions, the domination of the GHG + ASA-induced warming by the oscillation has obscured and confounded detection of this warming

Tunable Soft X-Ray Oscillators

International Nuclear Information System (INIS)

Wurtele, Jonathan; Gandhi, Punut; Gu, X.-W.; Fawley, William M.; Reinsch, Matthia; Penn, Gregory; Kim, K.-J.; Lindberg, Ryan; Zholents, Alexander

2010-01-01

A concept for a tunable soft x-ray free electron laser (FEL) photon source is presented and studied numerically. The concept is based on echo-enabled harmonic generation (EEHG), wherein two modulator-chicane sections impose high harmonic structure with much greater efficacy as compared to conventional high harmonic FELs that use only one modulator-chicane section. The idea proposed here is to replace the external laser power sources in the EEHG modulators with FEL oscillators, and to combine the bunching of the beam with the production of radiation. Tunability is accomplished by adjusting the magnetic chicanes while the two oscillators remain at a fixed frequency. This scheme eliminates the need to develop coherent sources with the requisite power, pulse length, and stability requirements by exploiting the MHz bunch repetition rates of FEL continuous wave (CW) sources driven by superconducting (SC) linacs. We present time-dependent GINGER simulation results for an EEHG scheme with an oscillator modulator at 43 nm employing 50percent reflective dielectric mirrors and a second modulator employing an external, 215-nm drive laser. Peak output of order 300 MW is obtained at 2.7 nm, corresponding to the 80th harmonic of 215 nm. An alternative single-cavity echo-oscillator scheme based on a 13.4 nm oscillator is investigated with time-independent simulations that a 180-MW peak power at final wavelength of 1.12 nm. Three alternate configurations that use separate bunches to produce the radiation for EEHG microbunching are also presented. Our results show that oscillator-based soft x-ray FELs driven by CWSC linacs are extremely attractive because of their potential to produce tunable radiation at high average power together with excellent longitudinal coherence and narrow spectral bandwidth.

Tunable Soft X-Ray Oscillators

Energy Technology Data Exchange (ETDEWEB)

Wurtele, Jonathan; Gandhi, Punut; Gu, X-W; Fawley, William M; Reinsch, Matthia; Penn, Gregory; Kim, K-J; Lindberg, Ryan; Zholents, Alexander

2010-09-17

A concept for a tunable soft x-ray free electron laser (FEL) photon source is presented and studied numerically. The concept is based on echo-enabled harmonic generation (EEHG), wherein two modulator-chicane sections impose high harmonic structure with much greater efficacy as compared to conventional high harmonic FELs that use only one modulator-chicane section. The idea proposed here is to replace the external laser power sources in the EEHG modulators with FEL oscillators, and to combine the bunching of the beam with the production of radiation. Tunability is accomplished by adjusting the magnetic chicanes while the two oscillators remain at a fixed frequency. This scheme eliminates the need to develop coherent sources with the requisite power, pulse length, and stability requirements by exploiting the MHz bunch repetition rates of FEL continuous wave (CW) sources driven by superconducting (SC) linacs. We present time-dependent GINGER simulation results for an EEHG scheme with an oscillator modulator at 43 nm employing 50percent reflective dielectric mirrors and a second modulator employing an external, 215-nm drive laser. Peak output of order 300 MW is obtained at 2.7 nm, corresponding to the 80th harmonic of 215 nm. An alternative single-cavity echo-oscillator scheme based on a 13.4 nm oscillator is investigated with time-independent simulations that a 180-MW peak power at final wavelength of 1.12 nm. Three alternate configurations that use separate bunches to produce the radiation for EEHG microbunching are also presented. Our results show that oscillator-based soft x-ray FELs driven by CWSC linacs are extremely attractive because of their potential to produce tunable radiation at high average power together with excellent longitudinal coherence and narrow spectral bandwidth.

Stochastic Kuramoto oscillators with discrete phase states

Science.gov (United States)

Jörg, David J.

2017-09-01

We present a generalization of the Kuramoto phase oscillator model in which phases advance in discrete phase increments through Poisson processes, rendering both intrinsic oscillations and coupling inherently stochastic. We study the effects of phase discretization on the synchronization and precision properties of the coupled system both analytically and numerically. Remarkably, many key observables such as the steady-state synchrony and the quality of oscillations show distinct extrema while converging to the classical Kuramoto model in the limit of a continuous phase. The phase-discretized model provides a general framework for coupled oscillations in a Markov chain setting.

Stochastic Kuramoto oscillators with discrete phase states.

Science.gov (United States)

Jörg, David J

2017-09-01

We present a generalization of the Kuramoto phase oscillator model in which phases advance in discrete phase increments through Poisson processes, rendering both intrinsic oscillations and coupling inherently stochastic. We study the effects of phase discretization on the synchronization and precision properties of the coupled system both analytically and numerically. Remarkably, many key observables such as the steady-state synchrony and the quality of oscillations show distinct extrema while converging to the classical Kuramoto model in the limit of a continuous phase. The phase-discretized model provides a general framework for coupled oscillations in a Markov chain setting.

Optimal parameters uncoupling vibration modes of oscillators

Science.gov (United States)

Le, K. C.; Pieper, A.

2017-07-01

This paper proposes a novel optimization concept for an oscillator with two degrees of freedom. By using specially defined motion ratios, we control the action of springs to each degree of freedom of the oscillator. We aim at showing that, if the potential action of the springs in one period of vibration, used as the payoff function for the conservative oscillator, is maximized among all admissible parameters and motions satisfying Lagrange's equations, then the optimal motion ratios uncouple vibration modes. A similar result holds true for the dissipative oscillator having dampers. The application to optimal design of vehicle suspension is discussed.

Chimera States in Neural Oscillators

Science.gov (United States)

Bahar, Sonya; Glaze, Tera

2014-03-01

Chimera states have recently been explored both theoretically and experimentally, in various coupled nonlinear oscillators, ranging from phase-oscillator models to coupled chemical reactions. In a chimera state, both coherent and incoherent (or synchronized and desynchronized) states occur simultaneously in populations of identical oscillators. We investigate chimera behavior in a population of neural oscillators using the Huber-Braun model, a Hodgkin-Huxley-like model originally developed to characterize the temperature-dependent bursting behavior of mammalian cold receptors. One population of neurons is allowed to synchronize, with each neuron receiving input from all the others in its group (global within-group coupling). Subsequently, a second population of identical neurons is placed under an identical global within-group coupling, and the two populations are also coupled to each other (between-group coupling). For certain values of the coupling constants, the neurons in the two populations exhibit radically different synchronization behavior. We will discuss the range of chimera activity in the model, and discuss its implications for actual neural activity, such as unihemispheric sleep.

Oscillating Finite Sums

KAUST Repository

Alabdulmohsin, Ibrahim M.

2018-01-01

In this chapter, we use the theory of summability of divergent series, presented earlier in Chap. 4, to derive the analogs of the Euler-Maclaurin summation formula for oscillating sums. These formulas will, in turn, be used to perform many remarkable deeds with ease. For instance, they can be used to derive analytic expressions for summable divergent series, obtain asymptotic expressions of oscillating series, and even accelerate the convergence of series by several orders of magnitude. Moreover, we will prove the notable fact that, as far as the foundational rules of summability calculus are concerned, summable divergent series behave exactly as if they were convergent.

Oscillating Finite Sums

KAUST Repository

Alabdulmohsin, Ibrahim M.

2018-03-07

In this chapter, we use the theory of summability of divergent series, presented earlier in Chap. 4, to derive the analogs of the Euler-Maclaurin summation formula for oscillating sums. These formulas will, in turn, be used to perform many remarkable deeds with ease. For instance, they can be used to derive analytic expressions for summable divergent series, obtain asymptotic expressions of oscillating series, and even accelerate the convergence of series by several orders of magnitude. Moreover, we will prove the notable fact that, as far as the foundational rules of summability calculus are concerned, summable divergent series behave exactly as if they were convergent.

Magnetically insulated transmission line oscillator

Science.gov (United States)

Bacon, L.D.; Ballard, W.P.; Clark, M.C.; Marder, B.M.

1987-05-19

A magnetically insulated transmission line oscillator employs self-generated magnetic fields to generate microwave energy. An anode of the oscillator includes slow-wave structures which are formed of a plurality of thin conductive vanes defining cavities therebetween, and a gap is formed between the anode and a cathode of the oscillator. In response to a pulsed voltage applied to the anode and cathode, self-generated magnetic fields are produced in a cross-field orientation with respect to the orientation of the electric field between the anode and the cathode. The cross-field magnetic fields insulate the flow of electrons in the gap and confine the flow of electrons within the gap. 11 figs.

Three flavour oscillation interpretation of neutrino data

Indian Academy of Sciences (India)

To explain the atmospheric neutrino problem in terms of neutrino oscillations, ЖС¾ of about 10-¿. eV. ¾. [8] is needed whereas the neutrino oscil- lation solution to the solar neutrino problem requires ЖС¾ ~10- eV. ¾ . Hence both solar and atmospheric neutrino problems cannot be explained in terms of e ° μ oscillations.

Entanglement of higher-derivative oscillators in holographic systems

Energy Technology Data Exchange (ETDEWEB)

Dimov, Hristo, E-mail: h_dimov@phys.uni-sofia.bg [Department of Physics, Sofia University, 5 J. Bourchier Blvd., 1164 Sofia (Bulgaria); Mladenov, Stefan, E-mail: smladenov@phys.uni-sofia.bg [Department of Physics, Sofia University, 5 J. Bourchier Blvd., 1164 Sofia (Bulgaria); Rashkov, Radoslav C., E-mail: rash@phys.uni-sofia.bg [Department of Physics, Sofia University, 5 J. Bourchier Blvd., 1164 Sofia (Bulgaria); Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstr. 8–10, 1040 Vienna (Austria); Vetsov, Tsvetan, E-mail: vetsov@phys.uni-sofia.bg [Department of Physics, Sofia University, 5 J. Bourchier Blvd., 1164 Sofia (Bulgaria)

2017-05-15

We study the quantum entanglement of coupled Pais–Uhlenbeck oscillators using the formalism of thermo-field dynamics. The entanglement entropy is computed for the specific cases of two and a ring of N coupled Pais–Uhlenbeck oscillators of fourth order. It is shown that the entanglement entropy depends on the temperatures, frequencies and coupling parameters of the different degrees of freedom corresponding to harmonic oscillators. We also make remarks on the appearance of instabilities of higher-derivative oscillators in the context of AdS/CFT correspondence. Finally, we advert to the information geometry theory by calculating the Fisher information metric for the considered system of coupled oscillators.

NREM sleep oscillations and brain plasticity in aging

Directory of Open Access Journals (Sweden)

Stuart eFogel

2012-12-01

Full Text Available The human electroencephalogram (EEG during non-rapid eye movement sleep (NREM is characterized mainly by high-amplitude (> 75 µV, slow-frequency (< 4 Hz waves (slow waves; SW and sleep spindles (~11-15 Hz; > 0.25 s. These NREM oscillations play a crucial role in brain plasticity, and importantly, NREM sleep oscillations change considerably with aging. This review discusses the association between NREM sleep oscillations and cerebral plasticity as well as the functional impact of age-related changes on NREM sleep oscillations. We propose that age-related reduction in sleep-dependent memory consolidation may be due in part to changes in NREM sleep oscillations.

Reducing pressure oscillations in discrete fluid power systems

DEFF Research Database (Denmark)

Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen

2016-01-01

Discrete fluid power systems featuring transmission lines inherently include pressure oscillations. Experimental verification of a discrete fluid power power take off system for wave energy converters has shown the cylinder pressure to oscillate as force shifts are performed. This article investi...... investigates how cylinder pressure oscillations may be reduced by shaping the valve opening trajectory without the need for closed loop pressure feedback. Furthermore the energy costs of reducing pressure oscillations are investigated....

Coherent oscillations between two weakly coupled Bose-Einstein condensates: Josephson effects, π oscillations, and macroscopic quantum self-trapping

International Nuclear Information System (INIS)

Raghavan, S.; Smerzi, A.; Fantoni, S.; Shenoy, S.R.

2001-03-01

We discuss the coherent atomic oscillations between two weakly coupled Bose-Einstein condensates. The weak link is provided by a laser barrier in a (possibly asymmetric) double-well trap or by Raman coupling between two condensates in different hyperfine levels. The boson Josephson junction (BJJ) dynamics is described by the two-mode nonlinear Gross-Pitaevskii equation that is solved analytically in terms of elliptic functions. The BJJ, being a neutral, isolated system, allows the investigations of dynamical regimes for the phase difference across the junction and for the population imbalance that are not accessible with superconductor Josephson junctions (SJJ's). These include oscillations with either or both of the following properties: (i) the time-averaged value of the phase is equal to π (π-phase oscillations); (ii) the average population imbalance is nonzero, in states with macroscopic quantum self-trapping. The (nonsinusoidal) generalization of the SJJ ac and plasma oscillations and the Shapiro resonance can also be observed. We predict the collapse of experimental data (corresponding to different trap geometries and the total number of condensate atoms) onto a single universal curve for the inverse period of oscillations. Analogies with Josephson oscillations between two weakly coupled reservoirs of 3 He-B and the internal Josephson effect in 3 He-A are also discussed. (author)

The vertical oscillations of coupled magnets

International Nuclear Information System (INIS)

Li Kewei; Lin Jiahuang; Kang Zi Yang; Liang, Samuel Yee Wei; Juan, Jeremias Wong Say

2011-01-01

The International Young Physicists' Tournament (IYPT) is a worldwide, annual competition for high school students. This paper is adapted from the winning solution to Problem 14, Magnetic Spring, as presented in the final round of the 23rd IYPT in Vienna, Austria. Two magnets were arranged on top of each other on a common axis. One was fixed, while the other could move vertically. Various parameters of interest were investigated, including the effective gravitational acceleration, the strength, size, mass and geometry of the magnets, and damping of the oscillations. Despite its simplicity, this setup yielded a number of interesting and unexpected relations. The first stage of the investigation was concerned only with the undamped oscillations of small amplitudes, and the period of small amplitude oscillations was found to be dependent only on the eighth root of important magnet properties such as its strength and mass. The second stage sought to investigate more general oscillations. A numerical model which took into account magnet size, magnet geometry and damping effects was developed to model the general oscillations. Air resistance and friction were found to be significant sources of damping, while eddy currents were negligible.

Non-linear oscillations of fluid in a container

NARCIS (Netherlands)

Verhagen, J.H.G.; van Wijngaarden, L.

1965-01-01

This paper is concerned with forced oscillations of fluid in a rectangular container. From the linearized approximation of the equations governing these oscillations, resonance frequencies are obtained for which the amplitude of the oscillations becomes infinite. Observation shows that under these

Open-loop control of quasiperiodic thermoacoustic oscillations

Science.gov (United States)

Guan, Yu; Gupta, Vikrant; Kashinath, Karthik; Li, Larry K. B.

2017-11-01

The open-loop application of periodic acoustic forcing has been shown to be a potentially effective strategy for controlling periodic thermoacoustic oscillations, but its effectiveness on aperiodic thermoacoustic oscillations is less clear. In this experimental study, we apply periodic acoustic forcing to a ducted premixed flame oscillating quasiperiodically at two incommensurate natural frequencies, f1 and f2. We find that (i) above a critical forcing amplitude, the system locks into the forcing by oscillating only at the forcing frequency ff, producing a closed periodic orbit in phase space with no evidence of the original T2 torus attractor; (ii) the critical forcing amplitude required for lock-in decreases as ff approaches either f1 or f2, resulting in characteristic ∨-shaped lock-in boundaries around the two natural modes; and (iii) for a wide range of forcing frequencies, the system's oscillation amplitude can be reduced to less than 20% of that of the unforced system. These findings show that the open-loop application of periodic acoustic forcing can be an effective strategy for controlling aperiodic thermoacoustic oscillations. This work was supported by the Research Grants Council of Hong Kong (Project No. 16235716 and 26202815).

Acoustic Pressure Oscillations Induced in I-Burner

Science.gov (United States)

Matsui, Kiyoshi

Iwama et al. invented the I-burner to investigate acoustic combustion instability in solid-propellant rockets (Proceedings of ICT Conference, 1994, pp. 26-1 26-14). Longitudinal pressure oscillations were induced in the combustion chamber of a thick-walled rocket by combustion of a stepped-perforation grain (I-burner). These oscillations were studied here experimentally. Two I-burners with an internal diameter of 80 mm and a length of 1208 mm or 2240 mm were made. The grain had stepped perforations (20 and 42 mm in diameter and 657 and 160 mm in length, respectively). Longitudinal pressure oscillations always occur in two stages when an HTPB (hydroxyl-terminated polybutadiene)/AP (ammonium perchlorate)/aluminum-powder propellant burns (54 tests; the highest average pressure in the combustion chamber was 9.5 29 MPa), but no oscillations occur when an HTPB/AP propellant burns (29 tests). The pressure oscillations are essentially linear, but dissipation adds a nonlinear nature to them. In the first stage, the amplitudes are small and the first wave group predominates. In the next stage, the amplitudes are large and many wave groups are present. The change in the grain form accompanying the combustion affects the pressure oscillations.

Self oscillating PWM modulators, a topological comparison

DEFF Research Database (Denmark)

Poulsen, Søren; Andersen, Michael Andreas E.

2004-01-01

or fs/ð range respectively, where fs is the switching frequency of the converter. For some applications this will require unacceptable high switching frequency to achieve enough control loop bandwidth for the desired dynamic performance. With self oscillating modulators, the open loop bandwidth is equal...... to fs which makes this type of modulators an excellent choice for a wide range of applications. Self oscillating PWM modulators can be made in a number of ways, either as voltage or current mode modulators, and the self oscillating behavior can be achieved either by using hysteresis control...... or by shaping the open loop function of the modulator so its gain and phase response causes a closed loop natural oscillation. The two main types of self oscillating modulators have many similarities, but differences in dynamic performance and linearity are present. The work presented is related to the author...

Oscillations in glycolysis in Saccharomyces cerevisiae

DEFF Research Database (Denmark)

Kloster, Antonina; Olsen, Lars Folke

2012-01-01

also decreases by stimulating the ATPase activity, e.g. by FCCP or Amphotericin B. Thus, ATPase activity strongly affects the glycolytic oscillations. We discuss these data in relation to a simple autocatalytic model of glycolysis which can reproduce the experimental data and explain the role...... of membrane-bound ATPases . In addition we also studied a recent detailed model of glycolysis and found that, although thismodel faithfully reproduces the oscillations of glycolytic intermediates observed experimentally, it is not able to explain the role of ATPase activity on the oscillations....

Quantum electronics maser amplifiers and oscillators

CERN Document Server

Fain, V M; Sanders, J H

2013-01-01

Quantum Electronics, Volume 2: Maser Amplifiers and Oscillators deals with the experimental and theoretical aspects of maser amplifiers and oscillators which are based on the principles of quantum electronics. It shows how the concepts and equations used in quantum electronics follow from the basic principles of theoretical physics.Comprised of three chapters, this volume begins with a discussion on the elements of the theory of quantum oscillators and amplifiers working in the microwave region, along with the practical achievements in this field. Attention is paid to two-level paramagnetic ma

Planar channeling and quasichanneling oscillations in a bent crystal

International Nuclear Information System (INIS)

Sytov, A.I.; Guidi, V.; Bagli, E.; Bandiera, L.; Germogli, G.; Mazzolari, A.; Tikhomirov, V.V.

2016-01-01

Particles passing through a crystal under planar channeling are captured by a continuous potential and experience transverse oscillations in their motion. As channeled particles approach the atomic planes, they are likely to be dechanneled. This effect is being used in ion-beam analysis with MeV energy. We study this effect in a bent crystal for positive and negative particles within a wide range of energies in sight of application of such crystals at accelerators. We look for the conditions for the observation or not of channeling oscillations in the deflection angle distribution in experiments where the beam passes through the bent crystal. Indeed a new kind of oscillations in the deflection angle distribution, strictly related to the motion of over-barrier particles, i.e. quasichanneled particles, is predicted. Such oscillations, named planar quasichanneling oscillations, possess a different nature than channeling oscillations. Through computer simulation, we study this effect and provided a theoretical interpretation for them. We show that channeling oscillations can be observed only for positive particles while quasichanneling oscillations can exist for particles with either sign. The conditions for experimental observation of channeling and quasichanneling oscillations at existing accelerators with available crystal are found and optimized. (orig.)

Planar channeling and quasichanneling oscillations in a bent crystal

Energy Technology Data Exchange (ETDEWEB)

Sytov, A.I. [Universita di Ferrara, Dipartimento di Fisica e Scienze della Terra, Ferrara (Italy); Belarusian State University, Research Institute for Nuclear Problems, Minsk (Belarus); INFN, Ferrara (Italy); Guidi, V.; Bagli, E.; Bandiera, L.; Germogli, G.; Mazzolari, A. [Universita di Ferrara, Dipartimento di Fisica e Scienze della Terra, Ferrara (Italy); INFN, Ferrara (Italy); Tikhomirov, V.V. [Belarusian State University, Research Institute for Nuclear Problems, Minsk (Belarus); INFN, Ferrara (Italy)

2016-02-15

Particles passing through a crystal under planar channeling are captured by a continuous potential and experience transverse oscillations in their motion. As channeled particles approach the atomic planes, they are likely to be dechanneled. This effect is being used in ion-beam analysis with MeV energy. We study this effect in a bent crystal for positive and negative particles within a wide range of energies in sight of application of such crystals at accelerators. We look for the conditions for the observation or not of channeling oscillations in the deflection angle distribution in experiments where the beam passes through the bent crystal. Indeed a new kind of oscillations in the deflection angle distribution, strictly related to the motion of over-barrier particles, i.e. quasichanneled particles, is predicted. Such oscillations, named planar quasichanneling oscillations, possess a different nature than channeling oscillations. Through computer simulation, we study this effect and provided a theoretical interpretation for them. We show that channeling oscillations can be observed only for positive particles while quasichanneling oscillations can exist for particles with either sign. The conditions for experimental observation of channeling and quasichanneling oscillations at existing accelerators with available crystal are found and optimized. (orig.)

An electronically tunable current-mode quadrature oscillator using PCAs

OpenAIRE

Herencsár, Norbert; Lahiri, Abhirup; Vrba, Kamil; Koton, Jaroslav

2012-01-01

The paper presents a new realization of active RC sinusoidal oscillator with electronically tunable condition and frequency of oscillation. As compared to the class of three resistors, two capacitors (3R-2C) based canonic oscillators, the proposed circuit here uses only two resistors and two capacitors as the passive components and still provides non-interactive tuning laws for the condition of oscillation (CO) and the frequency of oscillation (FO). The proposed circuit employs new bipolar pr...

Cyanohydrin reactions enhance glycolytic oscillations in yeast

DEFF Research Database (Denmark)

Hald, Bjørn Olav; Nielsen, Astrid Gram; Tortzen, Christian

2015-01-01

Synchronous metabolic oscillations can be induced in yeast by addition of glucose and removal of extracellular acetaldehyde (ACAx). Compared to other means of ACAx removal, cyanide robustly induces oscillations, indicating additional cyanide reactions besides ACA to lactonitrile conversion. Here......: a) by reducing [ACAx] relative to oscillation amplitude, b) by targeting multiple intracellular carbonyl compounds during fermentation, and c) by acting as a phase resetting stimulus....

Effect of boundary on controlled memristor-based oscillator

KAUST Repository

Fouda, Mohamed E.

2012-10-01

Recently, the applications of memristors have spread into many fields and especially in the circuit theory. Many models have been proposed for the HP-memristor based on the window functions. In this paper, we introduce a complete mathematical analysis of the controlled reactance-less oscillator for two different window functions of Joglekar\\'s model (linear and nonlinear dopant drift) to discuss the effect of changing the window function on the oscillator\\'s behavior. The generalized necessary and sufficient conditions based on the circuit elements and control voltages for both the linear and nonlinear models are introduced. Moreover, closed form expressions for the oscillation frequency and duty cycle are derived for these models and verified using PSPICE simulations showing an excellent matching. Finally a comparison between the linear and nonlinear models which shows their effect on the oscillation frequency and conditions of oscillation is introduced. © 2012 IEEE.

Self-sustained oscillations of complex genomic regulatory networks

International Nuclear Information System (INIS)

Ye Weiming; Huang Xiaodong; Huang Xuhui; Li Pengfei; Xia Qinzhi; Hu Gang

2010-01-01

Recently, self-sustained oscillations in complex networks consisting of non-oscillatory nodes have attracted great interest in diverse natural and social fields. Oscillatory genomic regulatory networks are one of the most typical examples of this kind. Given an oscillatory genomic network, it is important to reveal the central structure generating the oscillation. However, if the network consists of large numbers of genes and interactions, the oscillation generator is deeply hidden in the complicated interactions. We apply the dominant phase-advanced driving path method proposed in Qian et al. (2010) to reduce complex genomic regulatory networks to one-dimensional and unidirectionally linked network graphs where negative regulatory loops are explored to play as the central generators of the oscillations, and oscillation propagation pathways in the complex networks are clearly shown by tree branches radiating from the loops. Based on the above understanding we can control oscillations of genomic networks with high efficiency.

Pure odd-order oscillators with constant excitation

Science.gov (United States)

Cveticanin, L.

2011-02-01

In this paper the excited vibrations of a truly nonlinear oscillator are analyzed. The excitation is assumed to be constant and the nonlinearity is pure (without a linear term). The mathematical model is a second-order nonhomogeneous differential equation with strong nonlinear term. Using the first integral, the exact value of period of vibration i.e., angular frequency of oscillator described with a pure nonlinear differential equation with constant excitation is analytically obtained. The closed form solution has the form of gamma function. The period of vibration depends on the value of excitation and of the order and coefficient of the nonlinear term. For the case of pure odd-order-oscillators the approximate solution of differential equation is obtained in the form of trigonometric function. The solution is based on the exact value of period of vibration. For the case when additional small perturbation of the pure oscillator acts, the so called 'Cveticanin's averaging method' for a truly nonlinear oscillator is applied. Two special cases are considered: one, when the additional term is a function of distance, and the second, when damping acts. To prove the correctness of the method the obtained results are compared with those for the linear oscillator. Example of pure cubic oscillator with constant excitation and linear damping is widely discussed. Comparing the analytically obtained results with exact numerical ones it is concluded that they are in a good agreement. The investigations reported in the paper are of special interest for those who are dealing with the problem of vibration reduction in the oscillator with constant excitation and pure nonlinear restoring force the examples of which can be found in various scientific and engineering systems. For example, such mechanical systems are seats in vehicles, supports for machines, cutting machines with periodical motion of the cutting tools, presses, etc. The examples can be find in electronics

Magma chamber interaction giving rise to asymmetric oscillations

Science.gov (United States)

Walwer, D.; Ghil, M.; Calais, E.

2017-12-01

Geodetic time series at four volcanoes (Okmok, Akutan, Shishaldin, and Réunion) are processed using Multi-channel Singular Spectrum Analysis (M-SSA) and reveal sawtooth-shaped oscillations ; the latter are characterized by short intervals of fast inflations followed by longer intervals of slower deflations. At Okmok and Akutan, the oscillations are first damped and then accentuated. At Okmok, the increase in amplitude of the oscillations is followed by an eruption. We first show that the dynamics of these four volcanoes bears similarities with that of a simple nonlinear, dissipative oscillator, indicating that the inflation-deflation episodes are relaxation oscillations. These observations imply that ab initio dynamical models of magma chambers should possess an asymmetric oscillatory regime. Next, based on the work of Whitehead and Helfrich [1991], we show that a model of two magma chambers — connected by a cylindrical conduit in which the magma viscosity depends on temperature — gives rise to asymmetric overpressure oscillations in the magma reservoirs. These oscillations lead to surface deformations that are consistent with those observed at the four volcanoes in this study. This relaxation oscillation regime occurs only when the vertical temperature gradient in the host rock between the two magma chambers is large enough and when the magma flux entering the volcanic system is sufficiently high. The magma being supplied by a deeper source region, the input flux depends on the pressure difference between the source and the deepest reservoir. When this difference is not sufficiently high, the magma flux exponentially decreases, leading to damped oscillations as observed at Akutan and Okmok. The combination of observational and modeling results clearly supports the role of relaxation oscillations in the dynamics of volcanic systems.

Using qubits to reveal quantum signatures of an oscillator

Science.gov (United States)

Agarwal, Shantanu

In this thesis, we seek to study the qubit-oscillator system with the aim to identify and quantify inherent quantum features of the oscillator. We show that the quantum signatures of the oscillator get imprinted on the dynamics of the joint system. The two key features which we explore are the quantized energy spectrum of the oscillator and the non-classicality of the oscillator's wave function. To investigate the consequences of the oscillator's discrete energy spectrum, we consider the qubit to be coupled to the oscillator through the Rabi Hamiltonian. Recent developments in fabrication technology have opened up the possibility to explore parameter regimes which were conventionally inaccessible. Motivated by these advancements, we investigate in this thesis a parameter space where the qubit frequency is much smaller than the oscillator frequency and the Rabi frequency is allowed to be an appreciable fraction of the bare frequency of the oscillator. We use the adiabatic approximation to understand the dynamics in this quasi-degenerate qubit regime. By deriving a dressed master equation, we systematically investigate the effects of the environment on the system dynamics. We develop a spectroscopic technique, using which one can probe the steady state response of the driven and damped system. The spectroscopic signal clearly reveals the quantized nature of the oscillator's energy spectrum. We extend the adiabatic approximation, earlier developed only for the single qubit case, to a scenario where multiple qubits interact with the oscillator. Using the extended adiabatic approximation, we study the collapse and revival of multi-qubit observables. We develop analytic expressions for the revival signals which are in good agreement with the numerically evaluated results. Within the quantum restriction imposed by Heisenberg's uncertainty principle, the uncertainty in the position and momentum of an oscillator is minimum and shared equally when the oscillator is prepared

Retrospective evaluation of bone pain palliation after samarium-153-EDTMP therapy Avaliação retrospectiva do tratamento da dor óssea metastática com Samário-153-EDTMP

Directory of Open Access Journals (Sweden)

Marcelo Tatit Sapienza

2004-01-01

Full Text Available PURPOSE: The aim of this study was to evaluate the degree of metastatic bone pain palliation and medullar toxicity associated with samarium-153-EDTMP treatment. METHODS: Seventy-three patients with metastatic bone pain having previously undergone therapy with samarium-153-EDTMP (1 mCi/kg were retrospectively evaluated. Routine follow-up included pain evaluation and blood counts for 2 months after treatment. Pain was evaluated using a subjective scale (from 0 to 10 before and for 8 weeks after the treatment. Blood counts were obtained before treatment and once a week for 2 months during follow-up. Dosimetry, based upon the urinary excretion of the isotope, was estimated in 41 individuals, and the resulting radiation absorbed doses were correlated with hematological data. RESULTS: Reduction in pain scores of 75% to 100% was obtained in 36 patients (49%, with a decrease of 50% to 75%, 25% to 50%, and 0% to 25% in, respectively, 20 (27%, 10 (14%, and 7 (10% patients. There was no significant relationship between the pain response and location of the primary tumor (breast or prostate cancer. Mild to moderate myelosuppression was noted in 75.3% of patients, usually with hematological recovery at 8 weeks. The mean bone marrow dose was 347 ± 65 cGy, and only a weak correlation was found between absorbed dose and myelosuppression (Pearson coefficient = .4. CONCLUSIONS: Samarium-153-EDTMP is a valuable method for metastatic bone pain palliation. A mild to moderate and transitory myelosuppression is the main toxicity observed after samarium therapy, showing a weak correlation with dosimetric measures.OBJETIVO: O presente trabalho teve por objetivo avaliar o efeito paliativo da dor e a toxicidade medular associados ao tratamento com Samário-153-EDTMP em pacientes com metástases ósseas. MÉTODOS: O estudo foi realizado de forma retrospectiva, a partir do levantamento de prontuário de 178 pacientes submetidos a tratamento com 1mCi/kg de 153Sm

Introduction to Classical and Quantum Harmonic Oscillators

International Nuclear Information System (INIS)

Latal, H

1997-01-01

As the title aptly states, this book deals with harmonic oscillators of various kinds, from classical mechanical and electrical oscillations up to quantum oscillations. It is written in a lively language, and occasional interspersed anecdotes make the reading of an otherwise mathematically oriented text quite a pleasure. Although the author claims to have written an 'elementary introduction', it is certainly necessary to have a good deal of previous knowledge in physics (mechanics, electrodynamics, quantum theory), electrical engineering and, of course, mathematics in order to follow the general line of his arguments. The book begins with a thorough treatment of classical oscillators (free, damped, forced) that is followed by an elaboration on Fourier analysis. Lagrange and Hamilton formalisms are then introduced before the problem of coupled oscillations is attacked. A chapter on statistical perspectives leads over to the final discussion of quantum oscillations. With the book comes a diskette containing a number of worksheets (Microsoft Excel) that can be used by the reader for instant visualization to get a better qualitative and quantitative understanding of the material. To the reviewer it seems difficult to pinpoint exactly the range of prospective readership of the book. It can certainly not be intended as a textbook for students, but rather as a reference book for teachers of physics or researchers, who want to look up one or other aspect of harmonic oscillations, for which purpose the diskette represents a very valuable tool. (book review)

Synchrony-optimized networks of non-identical Kuramoto oscillators

International Nuclear Information System (INIS)

Brede, Markus

2008-01-01

In this Letter we discuss a method for generating synchrony-optimized coupling architectures of Kuramoto oscillators with a heterogeneous distribution of native frequencies. The method allows us to relate the properties of the coupling network to its synchronizability. These relations were previously only established from a linear stability analysis of the identical oscillator case. We further demonstrate that the heterogeneity in the oscillator population produces heterogeneity in the optimal coupling network as well. Two rules for enhancing the synchronizability of a given network by a suitable placement of oscillators are given: (i) native frequencies of adjacent oscillators must be anti-correlated and (ii) frequency magnitudes should positively correlate with the degree of the node they are placed at

Friedel oscillations in graphene

DEFF Research Database (Denmark)

Lawlor, J. A.; Power, S. R.; Ferreira, M.S.

2013-01-01

Symmetry breaking perturbations in an electronically conducting medium are known to produce Friedel oscillations in various physical quantities of an otherwise pristine material. Here we show in a mathematically transparent fashion that Friedel oscillations in graphene have a strong sublattice...... asymmetry. As a result, the presence of impurities and/or defects may impact the distinct graphene sublattices very differently. Furthermore, such an asymmetry can be used to explain the recent observations that nitrogen atoms and dimers are not randomly distributed in graphene but prefer to occupy one...

Solar-like oscillations in red giants observed with Kepler: comparison of global oscillation parameters from different methods

DEFF Research Database (Denmark)

Hekker, Saskia; Elsworth, Yvonne; De Ridder, Joris

2011-01-01

investigate the differences in results for global oscillation parameters of G and K red-giant stars due to different methods and definitions. We also investigate uncertainties originating from the stochastic nature of the oscillations. Methods: For this investigation we use Kepler data obtained during...... obtain results for the frequency of maximum oscillation power (ν_max) and the mean large separation () from different methods for over one thousand red-giant stars. The results for these parameters agree within a few percent and seem therefore robust to the different analysis methods and definitions...

Kuramoto model of coupled oscillators with positive and negative coupling parameters: an example of conformist and contrarian oscillators.

Science.gov (United States)

Hong, Hyunsuk; Strogatz, Steven H

2011-02-04

We consider a generalization of the Kuramoto model in which the oscillators are coupled to the mean field with random signs. Oscillators with positive coupling are "conformists"; they are attracted to the mean field and tend to synchronize with it. Oscillators with negative coupling are "contrarians"; they are repelled by the mean field and prefer a phase diametrically opposed to it. The model is simple and exactly solvable, yet some of its behavior is surprising. Along with the stationary states one might have expected (a desynchronized state, and a partially-synchronized state, with conformists and contrarians locked in antiphase), it also displays a traveling wave, in which the mean field oscillates at a frequency different from the population's mean natural frequency.

Phase Multistability in Coupled Oscillator Systems

DEFF Research Database (Denmark)

Mosekilde, Erik; Postnov, D.E.; Sosnovtseva, Olga

2003-01-01

along the orbit of the individual oscillator. Focusing on the mechanisms underlying the appearance of phase multistability, the paper examines a variety of phase-locked patterns. In particular we demonstrate the nested structure of synchronization regions for oscillations with multicrest wave forms...

Silicon Bipolar Distributed Oscillator Design and Analysis | Aku ...

African Journals Online (AJOL)

The design of high frequency silicon bipolar oscillator using common emitter (CE) with distributed output and analysis is carried out. The general condition for oscillation and the resulting analytical expressions for the frequency of oscillators were reviewed. Transmission line design was carried out using Butterworth LC ...

Effects of samarium (Sm) additions on the microstructure and mechanical properties of as-cast and hot-extruded Mg-5 wt%Al-3 wt%Ca-based alloys

International Nuclear Information System (INIS)

Son, Hyeon-Taek; Lee, Jae-Seol; Kim, Dae-Guen; Yoshimi, Kyosuke; Maruyama, Kouichi

2009-01-01

Samarium (Sm) additions to as-cast Mg-5Al-3Ca-based alloys result in changes, such as equiaxed grains and a refined grain size. The microstructure of as-cast Mg-5Al-3Ca-xSm alloys consists of an α-Mg matrix, a (Mg, Al) 2 Ca eutectic phase, and an Al 2 Sm intermetallic compound. In as-cast alloys, the (Mg, Al) 2 Ca eutectic phase was located at grain boundaries with a chain structure, and the Al 2 Sm intermetallic compounds were homogeneously distributed at the α-Mg matrix and grain boundaries. The eutectic phase of the extruded alloys was elongated in the extrusion direction and crushed into fine particles because of severe deformation during hot extrusion, and the grain size was refined with an increased amount of Sm addition. The maximum values of the yield strength and tensile strength were 313 MPa and 330 MPa at 2 wt%Sm alloy content, respectively

A Design Principle for a Posttranslational Biochemical Oscillator

Directory of Open Access Journals (Sweden)

Craig C. Jolley

2012-10-01

Full Text Available Multisite phosphorylation plays an important role in biological oscillators such as the circadian clock. Its general role, however, has been elusive. In this theoretical study, we show that a simple substrate with two modification sites acted upon by two opposing enzymes (e.g., a kinase and a phosphatase can show oscillations in its modification state. An unbiased computational analysis of this oscillator reveals two common characteristics: a unidirectional modification cycle and sequestering of an enzyme by a specific modification state. These two motifs cause a substrate to act as a coupled system in which a unidirectional cycle generates single-molecule oscillators, whereas sequestration synchronizes the population by limiting the available enzyme under conditions in which substrate is in excess. We also demonstrate the conditions under which the oscillation period is temperature compensated, an important feature of the circadian clock. This theoretical model will provide a framework for analyzing and synthesizing posttranslational oscillators.

Oyster Creek fuel thermal margin during core thermal-hydraulic oscillations

International Nuclear Information System (INIS)

Dougher, J.D.

1990-01-01

The Oyster Creek nuclear facility, a boiling water reactor (BWR)-2 plant type, has never experienced core thermal-hydraulic instability. Power oscillations, however, have been observed in other BWR cores both domestically and internationally. Two modes of oscillations have been observed, core wide and regional half-core. During core wide oscillations, the neutron flux in the core oscillates in the radial fundamental mode. During regional half-core oscillations, higher order harmonics in the radial plane result in out-of-phase oscillations with the neutron flux in one half of the core oscillating 180 deg out-of-phase with the neutron flux in the other half of the core. General Design Criteria 12 requires either prevention or detection and suppression of power oscillations which could result in violations of fuel design limits. Analyses performed by General Electric have demonstrated that for large-magnitude oscillations the potential exists for violation of the safety limit minimum critical power ratio (MCPR). However, for plants with a flow-biased neutron flux scram automatic mitigation of oscillations may be provided at an oscillation magnitude below that at which the safety limit is challenged. Plant-specific analysis for Oyster Creek demonstrates that the existing average power range monitor (APRM) system will sense and suppress power oscillations prior to violation of any safety limits

Condensate oscillations in a Penrose tiling lattice

Science.gov (United States)

Akdeniz, Z.; Vignolo, P.

2017-07-01

We study the dynamics of a Bose-Einstein condensate subject to a particular Penrose tiling lattice. In such a lattice, the potential energy at each site depends on the neighbour sites, accordingly to the model introduced by Sutherland [16]. The Bose-Einstein wavepacket, initially at rest at the lattice symmetry center, is released. We observe a very complex time-evolution that strongly depends on the symmetry center (two choices are possible), on the potential energy landscape dispersion, and on the interaction strength. The condensate-width oscillates at different frequencies and we can identify large-frequency reshaping oscillations and low-frequency rescaling oscillations. We discuss in which conditions these oscillations are spatially bounded, denoting a self-trapping dynamics.

First integral method for an oscillator system

Directory of Open Access Journals (Sweden)

Xiaoqian Gong

2013-04-01

Full Text Available In this article, we consider the nonlinear Duffing-van der Pol-type oscillator system by means of the first integral method. This system has physical relevance as a model in certain flow-induced structural vibration problems, which includes the van der Pol oscillator and the damped Duffing oscillator etc as particular cases. Firstly, we apply the Division Theorem for two variables in the complex domain, which is based on the ring theory of commutative algebra, to explore a quasi-polynomial first integral to an equivalent autonomous system. Then, through solving an algebraic system we derive the first integral of the Duffing-van der Pol-type oscillator system under certain parametric condition.

A test device for premixed gas turbine combustion oscillations

Energy Technology Data Exchange (ETDEWEB)

Richards, G.A.; Gemmen, R.S.; Yip, M.J.

1996-03-01

This report discusses design and operation of a single-nozzle test combustor for studying lean, premixed combustion oscillations from gas turbine fuel nozzles. It was used to study oscillations from a prototype fuel nozzle that produced oscillations during testing in a commercial engine. Similar, but not identical, oscillations were recorded in the test device. Basic requirements of the device design were that the flame geometry be maintained and acoustic losses be minimized; this was achieved by using a Helmholtz resonator as the combustor geometry. Surprisingly, the combustor oscillated strongly at several frequencies, without modification of the resonator. Brief survey of operating conditions suggests that it may be helpful to characterize oscillating behavior in terms of reference velocity and inlet air temperature with the rig backpressure playing a smaller role. The preliminary results do not guarantee that the single-nozzle test device will reproduce arbitrary oscillations that occur on a complete engine test. Nozzle/nozzle interactions may complicate the response, and oscillations controlled by acoustic velocities transverse to the nozzle axis may not be reproduced in a test device that relies on a bulk Helmholtz mode. Nevertheless, some oscillations can be reproduced, and the single-nozzle test device allows both active and passive control strategies to be tested relatively inexpensively.

Discontinuous Spirals of Stable Periodic Oscillations

DEFF Research Database (Denmark)

Sack, Achim; Freire, Joana G.; Lindberg, Erik

2013-01-01

We report the experimental discovery of a remarkable organization of the set of self-generated periodic oscillations in the parameter space of a nonlinear electronic circuit. When control parameters are suitably tuned, the wave pattern complexity of the periodic oscillations is found to increase...

Neutrino oscillations and neutrino-electron scattering

International Nuclear Information System (INIS)

Kayser, B.; Rosen, S.P.

1980-10-01

Neutrino flavor oscillations can significantly alter the cross section for neutrino-electron scattering. As a result, such oscillations can affect the comparison between existing reactor data and theories of neutral-current processes. They may also lead to strikingly large effects in high-energy accelerator experiments

Synchronization of indirectly coupled Lorenz oscillators

Indian Academy of Sciences (India)

Synchronization of indirectly coupled Lorenz oscillators: An experimental study. Amit Sharma Manish Dev Shrimali. Synchronization, Coupled Systems and Networks Volume 77 Issue 5 November 2011 pp 881-889 ... The in-phase and anti-phase synchronization of indirectly coupled chaotic oscillators reported in Phys. Rev ...

Experimental observation of shear thickening oscillation

DEFF Research Database (Denmark)

Nagahiro, Shin-ichiro; Nakanishi, Hiizu; Mitarai, Namiko

2013-01-01

We report experimental observations of the shear thickening oscillation, i.e. the spontaneous macroscopic oscillation in the shear flow of severe shear thickening fluid. Using a density-matched starch-water mixture, in the cylindrical shear flow of a few centimeters flow width, we observed...

Anti-synchronization of chaotic oscillators

International Nuclear Information System (INIS)

Kim, Chil-Min; Rim, Sunghwan; Kye, Won-Ho; Ryu, Jung-Wan; Park, Young-Jai

2003-01-01

We have observed anti-synchronization phenomena in coupled identical chaotic oscillators. Anti-synchronization can be characterized by the vanishing of the sum of relevant variables. We have qualitatively analyzed its base mechanism by using the dynamics of the difference and the sum of the relevant variables in coupled chaotic oscillators. Near the threshold of the synchronization and anti-synchronization transition, we have obtained the novel characteristic relation

From kaons to neutrinos: quantum mechanics of particle oscillations

International Nuclear Information System (INIS)

Zralek, M.

1998-01-01

The problem of particle oscillation is considered in a pedagogical and comprehensive way. Examples from K, B and neutrino physics are given. Conceptual difficulties of the traditional approach to particle oscillation are discussed. It is shown how the probability current density and the wave packet treatments of particle oscillations resolve some problems. It is also shown that only full field theoretical approach is free from conceptual difficulties. The possibility of oscillation of particles produced together with kaons or neutrinos is considered in full wave packet quantum mechanics language. Precise definition of the oscillation of particles which recoil against mixed states is given. The general amplitude which describes the oscillation of two particles in the final states is found. Using this EPR-type amplitude the problem of oscillation of particles recoiling against kaons or neutrinos is resolved. The relativistic EPR correlations on distances of the order of coherence lengths are considered. (author)

Anyons, deformed oscillator algebras and projectors

International Nuclear Information System (INIS)

Engquist, Johan

2009-01-01

We initiate an algebraic approach to the many-anyon problem based on deformed oscillator algebras. The formalism utilizes a generalization of the deformed Heisenberg algebras underlying the operator solution of the Calogero problem. We define a many-body Hamiltonian and an angular momentum operator which are relevant for a linearized analysis in the statistical parameter ν. There exists a unique ground state and, in spite of the presence of defect lines, the anyonic weight lattices are completely connected by the application of the oscillators of the algebra. This is achieved by supplementing the oscillator algebra with a certain projector algebra.

Microwave oscillator with 'whispering gallery' resonator

International Nuclear Information System (INIS)

Kirichenko, A.Ya.; Prokopenko, Yu.V.; Filippov, Yu.F.; Lonin, Yu.F.; Papkovich, V.G.; Ponomarev, A.G.; Prokopenko, Yu.V.; Uvarov, V.T.

2010-01-01

It was presented researches of a generation of microwave radiation into system with azimuthally periodical relativistic electron beam current that excites a high-Q quasi-optical dielectric resonator. The Eigen parameters of cylindrical Teflon resonator were determined by numerical computation. Registration of the microwave radiation realizes by a crystal set of 8-mm wavelength range. Research projects of microwave oscillators with high-Q resonators, in which 'whispering gallery' oscillations are excited by an electron flow, are presented. Multiresonator oscillators ideology is based on principles of microwave generation in klystrons with both subcritical and supercritical electron beams currents.

Time Series Decomposition into Oscillation Components and Phase Estimation.

Science.gov (United States)

Matsuda, Takeru; Komaki, Fumiyasu

2017-02-01

Many time series are naturally considered as a superposition of several oscillation components. For example, electroencephalogram (EEG) time series include oscillation components such as alpha, beta, and gamma. We propose a method for decomposing time series into such oscillation components using state-space models. Based on the concept of random frequency modulation, gaussian linear state-space models for oscillation components are developed. In this model, the frequency of an oscillator fluctuates by noise. Time series decomposition is accomplished by this model like the Bayesian seasonal adjustment method. Since the model parameters are estimated from data by the empirical Bayes' method, the amplitudes and the frequencies of oscillation components are determined in a data-driven manner. Also, the appropriate number of oscillation components is determined with the Akaike information criterion (AIC). In this way, the proposed method provides a natural decomposition of the given time series into oscillation components. In neuroscience, the phase of neural time series plays an important role in neural information processing. The proposed method can be used to estimate the phase of each oscillation component and has several advantages over a conventional method based on the Hilbert transform. Thus, the proposed method enables an investigation of the phase dynamics of time series. Numerical results show that the proposed method succeeds in extracting intermittent oscillations like ripples and detecting the phase reset phenomena. We apply the proposed method to real data from various fields such as astronomy, ecology, tidology, and neuroscience.

Characteristics of Oscillating Flames in a Coaxial Confined Jet

Directory of Open Access Journals (Sweden)

Min Suk Cha

2010-12-01

Full Text Available Flame characteristics when a non-premixed n-butane jet is ejected into a coaxial cylindrical tube are investigated experimentally. Flame stability depends mainly on the characteristics of flame propagation as well as air entrainment which depend on the jet momentum and on the distance between the nozzle exit and the base of a confined tube. As flow rate increases, the flame lifts off from a nozzle attached diffusion flame and a stationary lifted flame can be stabilized. The liftoff height increases nearly linearly with the average velocity at the nozzle exit. The lifted flame has a tribrachial flame structure, which consists of a rich premixed flame, a lean premixed flame, and a diffusion flame, all extending from a single location. As flow rate further increases, periodically oscillating flames are observed inside the confined tube. Once flame oscillation occurs, the flame undergoes relatively stable oscillation such that it has nearly constant oscillation amplitude and frequency. The criteria of flame oscillation are mapped as functions of nozzle diameter, the distance between nozzle and tube, and jet velocity. This type of flame oscillation can be characterized by Strouhal number in terms of flame oscillation amplitude, frequency, and jet velocity. Buoyancy driven flame oscillation which is one of the viable mechanism for flame oscillation is modeled and the results agrees qualitatively with experimental results, suggesting that the oscillation is due to periodic blowoff and flashback under the influence of buoyancy.

Reactor oscillator - I - III, Part III - Electronic device

International Nuclear Information System (INIS)

Lolic, B.; Jovanovic, S.

1961-12-01

This report describes functioning of the reactor oscillator electronic system. Two methods of oscillator operation were discussed. The first method is so called method of amplitude modulation of the reactor power, and the second newer method is phase method. Both methods are planned for the present reactor oscillator

Proprioceptive evoked gamma oscillations

DEFF Research Database (Denmark)

Arnfred, S.M.; Hansen, Lars Kai; Parnas, J.

2007-01-01

A proprioceptive stimulus consisting of a weight change of a handheld load has recently been shown to elicit an evoked potential. Previously, somatosensory gamma oscillations have only been evoked by electrical stimuli. We conjectured that a natural proprioceptive stimulus also would be able...... to evoke gamma oscillations. EEG was recorded using 64 channels in 14 healthy subjects. In each of three runs a stimulus of 100 g load increment in each hand was presented in 120 trials. Data were wavelet transformed and runs collapsed. Inter-trial phase coherence (ITPC) was computed as the best measure...

Antineutrino Oscillations in the Atmospheric Sector

International Nuclear Information System (INIS)

Himmel, Alexander I.

2011-01-01

This thesis presents measurements of the oscillations of muon antineutrinos in the atmospheric sector, where world knowledge of antineutrino oscillations lags well behind the knowledge of neutrinos, as well as a search for ν μ → (bar ν) μ transitions. Differences between neutrino and antineutrino oscillations could be a sign of physics beyond the Standard Model, including non-standard matter interactions or the violation of CPT symmetry. These measurements leverage the sign-selecting capabilities of the magnetized steel-scintillator MINOS detectors to analyze antineutrinos from the NuMI beam, both when it is in neutrino-mode and when it is in antineutrino-mode. Antineutrino oscillations are observed at |Δ(bar m) atm 2 | = (3.36 -0.40 +0.46 (stat) ± 0.06(syst)) x 10 -3 eV 2 and sin 2 (2(bar θ) 23 ) = 0.860 -0.12 +0.11 (stat) ± 0.01(syst). The oscillation parameters measured for antineutrinos and those measured by MINOS for neutrinos differ by a large enough margin that the chance of obtaining two values as discrepant as those observed is only 2%, assuming the two measurements arise from the same underlying mechanism, with the same parameter values. No evidence is seen for neutrino-to-antineutrino transitions.

Solar neutrinos and nonradial solar oscillations

International Nuclear Information System (INIS)

Zatsepin, G.T.; Gavryuseva, E.A.; Kopysov, Yu.S.

1980-01-01

The problem of origin of surface solar oscillations is considered. It is assumed that generation of oscillations is performed by the solar nucleus. The necessary excitation condition for gravitational oscillations of the solar nucleus is a sharp decrease of the oscillation amplitude outside the nucleus, where the nuclear reaction rates are small and only radiation losses are considerable. It is shown that the specific singularities of gravitational wave propagation in solar entrails permit to attain a significant reduction of the oscillation amplitude. The solar entrails can serve as an effective trap for gravitational waves, if the substance of the solar nucleus is close to the state of convectional equilibrium. In order that the g 1 quadrupole mode of the solar nucleus has a period of 2h 40 min and sharply decreases in the solar mantle, it is enough that only the external part of the solar nucleus is close to the state of convectional equilibrium. Closeness of the solar nucleus to the state of convectional equilibrium is an argument in favour of its periodic mixing. Periodic mixing of the solar nucleus can serve as a cause of a low counting rate of solar neutrinos in R.Davis chlorous detector

Quantum correlations in terms of neutrino oscillation probabilities

Energy Technology Data Exchange (ETDEWEB)

Alok, Ashutosh Kumar, E-mail: akalok@iitj.ac.in [Indian Institute of Technology Jodhpur, Jodhpur 342011 (India); Banerjee, Subhashish, E-mail: subhashish@iitj.ac.in [Indian Institute of Technology Jodhpur, Jodhpur 342011 (India); Uma Sankar, S., E-mail: uma@phy.iitb.ac.in [Indian Institute of Technology Bombay, Mumbai 400076 (India)

2016-08-15

Neutrino oscillations provide evidence for the mode entanglement of neutrino mass eigenstates in a given flavour eigenstate. Given this mode entanglement, it is pertinent to consider the relation between the oscillation probabilities and other quantum correlations. In this work, we show that all the well-known quantum correlations, such as the Bell's inequality, are directly related to the neutrino oscillation probabilities. The results of the neutrino oscillation experiments, which measure the neutrino survival probability to be less than unity, imply Bell's inequality violation.

OnWien Bridge Oscillators as Modified Multi-vibrators

DEFF Research Database (Denmark)

Lindberg, Erik

2014-01-01

A tutorial introduction to electrical oscilla- tors. Investigating Wien bridge oscillators as modified multi-vibrators. Introducing chaotic behavior into a Wien bridge oscillator by means of adding a simple nonlinear cir- cuit as a load of one of the amplifier input terminals......A tutorial introduction to electrical oscilla- tors. Investigating Wien bridge oscillators as modified multi-vibrators. Introducing chaotic behavior into a Wien bridge oscillator by means of adding a simple nonlinear cir- cuit as a load of one of the amplifier input terminals...

Triple inverter pierce oscillator circuit suitable for CMOS

Science.gov (United States)

Wessendorf,; Kurt, O [Albuquerque, NM

2007-02-27

An oscillator circuit is disclosed which can be formed using discrete field-effect transistors (FETs), or as a complementary metal-oxide-semiconductor (CMOS) integrated circuit. The oscillator circuit utilizes a Pierce oscillator design with three inverter stages connected in series. A feedback resistor provided in a feedback loop about a second inverter stage provides an almost ideal inverting transconductance thereby allowing high-Q operation at the resonator-controlled frequency while suppressing a parasitic oscillation frequency that is inherent in a Pierce configuration using a "standard" triple inverter for the sustaining amplifier. The oscillator circuit, which operates in a range of 10 50 MHz, has applications for use as a clock in a microprocessor and can also be used for sensor applications.

Prediction of pilot induced oscillations

Directory of Open Access Journals (Sweden)

Valentin PANĂ

2011-03-01

Full Text Available An important problem in the design of flight-control systems for aircraft under pilotedcontrol is the determination of handling qualities and pilot-induced oscillations (PIO tendencieswhen significant nonlinearities exist in the vehicle description. The paper presents a method to detectpossible pilot-induced oscillations of Category II (with rate and position limiting, a phenomenonusually due to a misadaptation between the pilot and the aircraft response during some tasks in whichtight closed loop control of the aircraft is required from the pilot. For the analysis of Pilot in the LoopOscillations an approach, based on robust stability analysis of a system subject to uncertainparameters, is proposed. In this analysis the nonlinear elements are substituted by linear uncertainparameters. This approach assumes that PIO are characterized by a limit cycle behavior.

Multi-mode interactions in an FEL oscillator

CERN Document Server

Dong Zhi Wei; Masuda, K; Yamazaki, T; Yoshikawa, K

2000-01-01

A 3D time-dependent FEL oscillator simulation code has been developed by using the transverse mode spectral method to analyze interaction among transverse modes. The competition among them in an FEL oscillator was investigated based on the parameters of LANL FEL experiments. It is found that under typical FEL oscillator operation conditions, the TEM sub 0 sub 0 mode is dominant, and the effects of other transverse modes can be negligible.

Self-induced free surface oscillations caused by water jet

International Nuclear Information System (INIS)

Fukaya, M.; Madarame, H.; Okamoto, K.; Iida, M.; Someya, S.

1995-01-01

The interaction between the high speed flow and the free surfaces could induced surface oscillations. Recently, some kinds of self-induced free surface oscillations caused by water jet were discovered, e.g., a self-induced sloshing, 'Jet-Flutter' and a self-induced manometer oscillation. These oscillations have many different characteristics with each other. In this study, the similarities and differences of these oscillations are examined, and the geometrical effects on the phenomena are experimentally investigated. The self-induced sloshing and the Jet-Flutter have different dimensionless traveling times, which suggests a difference in the energy supply mechanism. When the distance between the inlet and the outlet is small in a vessel, the self-induced manometer oscillation could occur in the multi-free-surface system. (author)

Analytic Neutrino Oscillation Probabilities in Matter: Revisited

Energy Technology Data Exchange (ETDEWEB)

Parke, Stephen J. [Fermilab; Denton, Peter B. [Copenhagen U.; Minakata, Hisakazu [Madrid, IFT

2018-01-02

We summarize our recent paper on neutrino oscillation probabilities in matter, explaining the importance, relevance and need for simple, highly accurate approximations to the neutrino oscillation probabilities in matter.

Recurring events. Power oscillations in BWRs

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-12-01

During almost two decennia, the recurrence of power oscillations in domestic and foreign BWRs has represented a challenge to one important design safety criterion, even if the occurred power oscillations have not resulted in conditions exceeding the specified fuel design limits. Several reasons may explain the recurrence. One reason has been a worldwide trend for an aggressive fuel economy optimisation, which from time to another has resulted in reduced core stability margins. Another reason relates to the analytical tools for prediction of core stability. These tools were scarce during many years. A third aspect is that adequate and reliable core monitors were not early available for installation at the plants. Issues related to power oscillations have during many years received attention from both the regulatory body and utilities, and from the fuel manufacturers. The present report provides examples of important corrective actions which support this conclusion. However, recent events indicate that the complex issue of BWR power oscillations has not been suitably solved, at least domestically.

Recurring events. Power oscillations in BWRs

International Nuclear Information System (INIS)

2000-12-01

During almost two decennia, the recurrence of power oscillations in domestic and foreign BWRs has represented a challenge to one important design safety criterion, even if the occurred power oscillations have not resulted in conditions exceeding the specified fuel design limits. Several reasons may explain the recurrence. One reason has been a worldwide trend for an aggressive fuel economy optimisation, which from time to another has resulted in reduced core stability margins. Another reason relates to the analytical tools for prediction of core stability. These tools were scarce during many years. A third aspect is that adequate and reliable core monitors were not early available for installation at the plants. Issues related to power oscillations have during many years received attention from both the regulatory body and utilities, and from the fuel manufacturers. The present report provides examples of important corrective actions which support this conclusion. However, recent events indicate that the complex issue of BWR power oscillations has not been suitably solved, at least domestically

Optics-free x-ray FEL oscillator

International Nuclear Information System (INIS)

Litvinenko, V.N.; Hao, Y.; Kayran, D.; Trbojevic, D.

2011-01-01

There is a need for an Optics-Free FEL Oscillators (OFFELO) to further the advantages of free-electron lasers and turning them in fully coherent light sources. While SASE (Self-Amplified Spontaneous Emission) FELs demonstrated the capability of providing very high gain and short pulses of radiation and scalability to the X-ray range, the spectra of SASE FELs remains rather wide (∼0.5%-1%) compared with typical short wavelengths FEL-oscillators (0.01%-0.0003% in OK-4 FEL). Absence of good optics in VUV and X-ray ranges makes traditional oscillator schemes with very high average and peak spectral brightness either very complex or, strictly speaking, impossible. In this paper, we discuss lattice of the X-ray optics-free FEL oscillator and present results of initial computer simulations of the feedback process and the evolution of FEL spectrum in X-ray OFFELO. We also discuss main limiting factors and feasibility of X-ray OFFELO.

Optics-free x-ray FEL oscillator

Energy Technology Data Exchange (ETDEWEB)

Litvinenko, V.N.; Hao, Y.; Kayran, D.; Trbojevic, D.

2011-03-28

There is a need for an Optics-Free FEL Oscillators (OFFELO) to further the advantages of free-electron lasers and turning them in fully coherent light sources. While SASE (Self-Amplified Spontaneous Emission) FELs demonstrated the capability of providing very high gain and short pulses of radiation and scalability to the X-ray range, the spectra of SASE FELs remains rather wide ({approx}0.5%-1%) compared with typical short wavelengths FEL-oscillators (0.01%-0.0003% in OK-4 FEL). Absence of good optics in VUV and X-ray ranges makes traditional oscillator schemes with very high average and peak spectral brightness either very complex or, strictly speaking, impossible. In this paper, we discuss lattice of the X-ray optics-free FEL oscillator and present results of initial computer simulations of the feedback process and the evolution of FEL spectrum in X-ray OFFELO. We also discuss main limiting factors and feasibility of X-ray OFFELO.

Oscillations and chaos in renal blood flow control

DEFF Research Database (Denmark)

Holstein-Rathlou, N H

1993-01-01

In normotensive, halothane-anesthetized rats, oscillations can be found both in the single-nephron blood flow and in the tubular pressure. Experimental data and computer simulations support the hypothesis that the oscillations are caused by the tubuloglomerular feedback (TGF) mechanism. Model...... oscillations. The parameter range where model studies show instability overlaps with the physiologic range for the values of the same parameters. The system appears to be poised on the border between stability and oscillation, and a small parameter change may cause the system to move from one state...

Chirality oscillation of primordial gravitational waves during inflation

Energy Technology Data Exchange (ETDEWEB)

Cai, Yong; Wang, Yu-Tong [School of Physics, University of Chinese Academy of Sciences,Beijing 100049 (China); Piao, Yun-Song [School of Physics, University of Chinese Academy of Sciences,Beijing 100049 (China); Institute of Theoretical Physics, Chinese Academy of Sciences,P.O. Box 2735, Beijing 100190 (China)

2017-03-06

We show that if the gravitational Chern-Simons term couples to a massive scalar field (m>H), the primordial gravitational waves (GWs) will show itself the chirality oscillation, i.e., the amplitudes of the left- and right-handed GWs modes will convert into each other and oscillate in their propagations. This oscillation will eventually develop a permanent difference of the amplitudes of both modes, which leads to nearly opposite oscillating shapes in the power spectra of the left- and right-handed primordial GWs. We discuss its implication to the CMB B-mode polarization.

Chaos in generically coupled phase oscillator networks with nonpairwise interactions.

Science.gov (United States)

Bick, Christian; Ashwin, Peter; Rodrigues, Ana

2016-09-01

The Kuramoto-Sakaguchi system of coupled phase oscillators, where interaction between oscillators is determined by a single harmonic of phase differences of pairs of oscillators, has very simple emergent dynamics in the case of identical oscillators that are globally coupled: there is a variational structure that means the only attractors are full synchrony (in-phase) or splay phase (rotating wave/full asynchrony) oscillations and the bifurcation between these states is highly degenerate. Here we show that nonpairwise coupling-including three and four-way interactions of the oscillator phases-that appears generically at the next order in normal-form based calculations can give rise to complex emergent dynamics in symmetric phase oscillator networks. In particular, we show that chaos can appear in the smallest possible dimension of four coupled phase oscillators for a range of parameter values.

Chaos in generically coupled phase oscillator networks with nonpairwise interactions

Energy Technology Data Exchange (ETDEWEB)

Bick, Christian; Ashwin, Peter; Rodrigues, Ana [Centre for Systems, Dynamics and Control and Department of Mathematics, University of Exeter, Exeter EX4 4QF (United Kingdom)

2016-09-15

The Kuramoto–Sakaguchi system of coupled phase oscillators, where interaction between oscillators is determined by a single harmonic of phase differences of pairs of oscillators, has very simple emergent dynamics in the case of identical oscillators that are globally coupled: there is a variational structure that means the only attractors are full synchrony (in-phase) or splay phase (rotating wave/full asynchrony) oscillations and the bifurcation between these states is highly degenerate. Here we show that nonpairwise coupling—including three and four-way interactions of the oscillator phases—that appears generically at the next order in normal-form based calculations can give rise to complex emergent dynamics in symmetric phase oscillator networks. In particular, we show that chaos can appear in the smallest possible dimension of four coupled phase oscillators for a range of parameter values.

Developmental Changes in Sleep Oscillations during Early Childhood

Directory of Open Access Journals (Sweden)

Eckehard Olbrich

2017-01-01

Full Text Available Although quantitative analysis of the sleep electroencephalogram (EEG has uncovered important aspects of brain activity during sleep in adolescents and adults, similar findings from preschool-age children remain scarce. This study utilized our time-frequency method to examine sleep oscillations as characteristic features of human sleep EEG. Data were collected from a longitudinal sample of young children (n=8; 3 males at ages 2, 3, and 5 years. Following sleep stage scoring, we detected and characterized oscillatory events across age and examined how their features corresponded to spectral changes in the sleep EEG. Results indicated a developmental decrease in the incidence of delta and theta oscillations. Spindle oscillations, however, were almost absent at 2 years but pronounced at 5 years. All oscillatory event changes were stronger during light sleep than slow-wave sleep. Large interindividual differences in sleep oscillations and their characteristics (e.g., “ultrafast” spindle-like oscillations, theta oscillation incidence/frequency also existed. Changes in delta and spindle oscillations across early childhood may indicate early maturation of the thalamocortical system. Our analytic approach holds promise for revealing novel types of sleep oscillatory events that are specific to periods of rapid normal development across the lifespan and during other times of aberrant changes in neurobehavioral function.

Auto-indexing of oscillation images

International Nuclear Information System (INIS)

Higashi, Tsuneyuki

1990-01-01

A method is presented which indexes spots recorded on single oscillation images without any a priori knowledge of cell parameters. The strategy is similar to that used in four-circle diffractometry and the method works in a fully automatic manner. It is applicable to multiple oscillation images or multiple stills. A complementary method is also described to obtain orientation angles for the case where cell parameters have already been determined. (orig.)

Oscillation theory for second order dynamic equations

CERN Document Server

Agarwal, Ravi P; O''Regan, Donal

2003-01-01

The qualitative theory of dynamic equations is a rapidly developing area of research. In the last 50 years, the Oscillation Theory of ordinary, functional, neutral, partial and impulsive differential equations, and their discrete versions, has inspired many scholars. Hundreds of research papers have been published in every major mathematical journal. Many books deal exclusively with the oscillation of solutions of differential equations, but most of these books appeal only to researchers who already know the subject. In an effort to bring Oscillation Theory to a new and broader audience, the authors present a compact, but thorough, understanding of Oscillation Theory for second order differential equations. They include several examples throughout the text not only to illustrate the theory, but also to provide new direction.

Superconducting low-noise oscillator

International Nuclear Information System (INIS)

Riebman, L.

1992-01-01

This patent describes a cryogenic oscillator having low phase noise and low noise. It comprises resonant circuit means formed of superconducting material for generating a signal at a desired frequency; linear amplifier means electrically connected to the resonant circuit means at first and second locations thereon; limiter means electrically connected to the resonant circuit means at a third location thereon; and buffer amplifier means for applying the signal generated by the resonant circuit means to a load and electrically connected to the resonant circuit means at a fourth location thereon. This patent also describes a method of minimizing phase noise and 1/f noise in an oscillator circuit of the type having a resonant circuit driving a load and at least a linear amplifier connected to the resonant circuit defining a closed loop having a loop gain greater than unity, and having a limiter for stabilizing the oscillator. It comprises connecting between the resonant circuit and the load a buffer amplifier and connecting the linear amplifier and the buffer amplifier to the resonant circuit

Micro-machined resonator oscillator

Science.gov (United States)

Koehler, Dale R.; Sniegowski, Jeffry J.; Bivens, Hugh M.; Wessendorf, Kurt O.

1994-01-01

A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available.

Mode competition and hopping in optomechanical nano-oscillators

Science.gov (United States)

Zhang, Xingwang; Lin, Tong; Tian, Feng; Du, Han; Zou, Yongchao; Chau, Fook Siong; Zhou, Guangya

2018-04-01

We investigate the inter-mode nonlinear interaction in the multi-mode optomechanical nano-oscillator which consists of coupled silicon nanocantilevers, where the integrated photonic crystal nanocavities provide the coupling between the optical and mechanical modes. Due to the self-saturation and cross-saturation of the mechanical gain, the inter-mode competition is observed, which leads to the bistable operation of the optomechanical nano-oscillator: only one of the mechanical modes can oscillate at any one time, and the oscillation of one mode extremely suppresses that of the other with a side mode suppression ratio (SMSR) up to 40 dB. In the meantime, mode hopping, i.e., the optomechanical oscillation switches from one mode to the other, is also observed and found to be able to be provoked by excitation laser fluctuations.

Harmonic and Anharmonic Behaviour of a Simple Oscillator

Science.gov (United States)

O'Shea, Michael J.

2009-01-01

We consider a simple oscillator that exhibits harmonic and anharmonic regimes and analyse its behaviour over the complete range of possible amplitudes. The oscillator consists of a mass "m" fixed at the midpoint of a horizontal rope. For zero initial rope tension and small amplitude the period of oscillation, tau, varies as tau is approximately…

Oscillator representations for self-adjoint Calogero Hamiltonians

Energy Technology Data Exchange (ETDEWEB)

Gitman, D M [Institute of Physics, University of Sao Paulo (Brazil); Tyutin, I V; Voronov, B L, E-mail: gitman@dfn.if.usp.br, E-mail: tyutin@lpi.ru, E-mail: voronov@lpi.ru [Lebedev Physical Institute, Moscow (Russian Federation)

2011-10-21

In Gitman et al (2010 J. Phys. A: Math. Theor. 43 145205), we presented a mathematically rigorous quantum-mechanical treatment of a one-dimensional motion of a particle in the Calogero potential V(x) = {alpha}x{sup -2}. We described all possible self-adjoint (s.a.) operators (s.a. Hamiltonians) associated with the differential operation H=-d{sub x}{sup 2}+{alpha}x{sup -2} for the Calogero Hamiltonian. Here, we discuss a new aspect of the problem, the so-called oscillator representations for the Calogero Hamiltonians. As is known, operators of the form N-hat = a-hat{sup +} a-hat and A-hat = a-hat a-hat{sup +} are called operators of oscillator type. Oscillator-type operators possess a number of useful properties in the case when the elementary operators a-hat are closed. It turns out that some s.a. Calogero Hamiltonians allow oscillator-type representations. We describe such Hamiltonians and find the corresponding mutually adjoint elementary operators a-hat and a-hat{sup +}. An oscillator-type representation for a given Hamiltonian is generally not unique. (paper)

Oscillator representations for self-adjoint Calogero Hamiltonians

International Nuclear Information System (INIS)

Gitman, D M; Tyutin, I V; Voronov, B L

2011-01-01

In Gitman et al (2010 J. Phys. A: Math. Theor. 43 145205), we presented a mathematically rigorous quantum-mechanical treatment of a one-dimensional motion of a particle in the Calogero potential V(x) = αx -2 . We described all possible self-adjoint (s.a.) operators (s.a. Hamiltonians) associated with the differential operation H=-d x 2 +αx -2 for the Calogero Hamiltonian. Here, we discuss a new aspect of the problem, the so-called oscillator representations for the Calogero Hamiltonians. As is known, operators of the form N-hat = a-hat + a-hat and A-hat = a-hat a-hat + are called operators of oscillator type. Oscillator-type operators possess a number of useful properties in the case when the elementary operators a-hat are closed. It turns out that some s.a. Calogero Hamiltonians allow oscillator-type representations. We describe such Hamiltonians and find the corresponding mutually adjoint elementary operators a-hat and a-hat + . An oscillator-type representation for a given Hamiltonian is generally not unique. (paper)

Homotopic mapping solution of an oscillator for the El Niño/La Niña-southern oscillation

International Nuclear Information System (INIS)

Xian-Chun, Zhou; Yi-Hua, Lin; Wan-Tao, Lin; Jia-Qi, Mo

2009-01-01

This paper considers a class of oscillator for the El Niño/La Niña-southern oscillation (ENSO) model. By using the homotopic mapping method, it obtains approximations of the solution for the ENSO model. (general)

Nanotube bundle oscillators: Carbon and boron nitride nanostructures

International Nuclear Information System (INIS)

Thamwattana, Ngamta; Hill, James M.

2009-01-01

In this paper, we investigate the oscillation of a fullerene that is moving within the centre of a bundle of nanotubes. In particular, certain fullerene-nanotube bundle oscillators, namely C 60 -carbon nanotube bundle, C 60 -boron nitride nanotube bundle, B 36 N 36 -carbon nanotube bundle and B 36 N 36 -boron nitride nanotube bundle are studied using the Lennard-Jones potential and the continuum approach which assumes a uniform distribution of atoms on the surface of each molecule. We address issues regarding the maximal suction energies of the fullerenes which lead to the generation of the maximum oscillation frequency. Since bundles are also found to comprise double-walled nanotubes, this paper also examines the oscillation of a fullerene inside a double-walled nanotube bundle. Our results show that the frequencies obtained for the oscillation within double-walled nanotube bundles are slightly higher compared to those of single-walled nanotube bundle oscillators. Our primary purpose here is to extend a number of established results for carbon to the boron nitride nanostructures.

Oscillation criteria for delay difference equations

Directory of Open Access Journals (Sweden)

Jianhua Shen

2001-01-01

Full Text Available This paper is concerned with the oscillation of all solutions of the delay difference equation $$ x_{n+1}-x_n+p_nx_{n-k}=0, quad n=0,1,2,dots $$ where ${p_n}$ is a sequence of nonnegative real numbers and $k$ is a positive integer. Some new oscillation conditions are established. These conditions concern the case when none of the well-known oscillation conditions $$ limsup_{no infty}sum_{i=0}^kp_{n-i}>1 quad{ m and}quad liminf_{no infty}frac{1}{k}sum_{i=1}^kp_{n-i}>frac{k^k}{(k+1^{k+1}} $$ is satisfied.

NOx Emission Reduction by Oscillating Combustion

Energy Technology Data Exchange (ETDEWEB)

John C. Wagner

2004-03-31

High-temperature, natural gas-fired furnaces, especially those fired with preheated air, produce large quantities of NO{sub x} per ton of material processed. Regulations on emissions from industrial furnaces are becoming increasingly more stringent. In addition, competition is forcing operators to make their furnaces more productive and/or efficient. Switching from preheated air to industrial oxygen can increase efficiency and reduce NO{sub x}, but oxygen is significantly more costly than air and may not be compatible with the material being heated. What was needed, and what was developed during this project, is a technology that reduces NO{sub x} emissions while increasing furnace efficiency for both air- and oxy-fired furnaces. Oscillating combustion is a retrofit technology that involves the forced oscillation of the fuel flow rate to a furnace. These oscillations create successive, fuel-rich and fuel-lean zones within the furnace. Heat transfer from the flame to the load increases due to the more luminous fuel-rich zones, a longer overall flame length, and the breakup of the thermal boundary layer. The increased heat transfer shortens heat up times, thereby increasing furnace productivity, and reduces the heat going up the stack, thereby increasing efficiency. The fuel-rich and fuel-lean zones also produce substantially less NO{sub x} than firing at a constant excess air level. The longer flames and higher heat transfer rate reduces overall peak flame temperature and thus reduces additional NO{sub x} formation from the eventual mixing of the zones and burnout of combustibles from the rich zones. This project involved the development of hardware to implement oscillating combustion on an industrial scale, the laboratory testing of oscillating combustion on various types of industrial burners, and the field testing of oscillating combustion on several types of industrial furnace. Before laboratory testing began, a market study was conducted, based on the

NOx Emission Reduction by Oscillating combustion

Energy Technology Data Exchange (ETDEWEB)

Institute of Gas Technology

2004-01-30

High-temperature, natural gas-fired furnaces, especially those fired with preheated air, produce large quantities of NO{sub x} per ton of material processed. Regulations on emissions from industrial furnaces are becoming increasingly more stringent. In addition, competition is forcing operators to make their furnaces more productive and/or efficient. Switching from preheated air to industrial oxygen can increase efficiency and reduce NO{sub x}, but oxygen is significantly more costly than air and may not be compatible with the material being heated. What was needed, and what was developed during this project, is a technology that reduces NO{sub x} emissions while increasing furnace efficiency for both air- and oxy-fired furnaces. Oscillating combustion is a retrofit technology that involves the forced oscillation of the fuel flow rate to a furnace. These oscillations create successive, fuel-rich and fuel-lean zones within the furnace. Heat transfer from the flame to the load increases due to the more luminous fuel-rich zones, a longer overall flame length, and the breakup of the thermal boundary layer. The increased heat transfer shortens heat up times, thereby increasing furnace productivity, and reduces the heat going up the stack, thereby increasing efficiency. The fuel-rich and fuel-lean zones also produce substantially less NO{sub x} than firing at a constant excess air level. The longer flames and higher heat transfer rate reduces overall peak flame temperature and thus reduces additional NO{sub x} formation from the eventual mixing of the zones and burnout of combustibles from the rich zones. This project involved the development of hardware to implement oscillating combustion on an industrial scale, the laboratory testing of oscillating combustion on various types of industrial burners, and the field testing of oscillating combustion on several types of industrial furnace. Before laboratory testing began, a market study was conducted, based on the

Oscillating and rotating sine-Gordon system

DEFF Research Database (Denmark)

Olsen, O. H.; Samuelsen, Mogens Rugholm

1986-01-01

The interaction between a 2π kink and the background or vacuum is investigated in the pure sine-Gordon system. For an oscillating background (i.e., the k=0 part of the phonon spectrum) the 2π kink oscillates, while for increasing or decreasing vacuum two phenomena have been observed, depending...

Three-dimensional analysis of nonlinear plasma oscillation

International Nuclear Information System (INIS)

Miano, G.

1990-01-01

In an underdense plasma a large-amplitude plasma oscillation may be produced by the beating of two external and colinear electromagnetic waves with a frequency difference approximately equal to the plasma frequency - plasma beat wave (PBW) resonant mechanism. The plasma oscillations are driven by the ponderomotive force arising from the beating of the two imposed electromagnetic waves. In this paper two pump electromagnetic waves with arbitrary transverse profiles have been considered. The plasma is described by using the three dimensinal weakly relativistic fluid equations. The nonlinear plasma oscillation dynamics is studied by using the eulerian description, the averaging and the multiple time scale methods. Unlike the linear theory a strong cross field coupling between longitudinal ans transverse electric field components of the plasma oscillation comes out, resulting in a nonlinear phase change and energy transfer between the two components. Unlike the one-dimensional nonlinear theory, the nonlinear frequency shift is caused by relativistic effects as well as by convective effects and electromagnetic field generated from the three dimensional plasma oscillation. The large amplitude plasma oscillation dynamics produced by a bunched relativistic electron beam with arbitrary transverse profile - plasma wave field (PWF) - or by a high power single frequency short electromagnetic pulse with arbitrary transverse profile - electromagnetic plasma wake field (EPWF) - may be described by means of the present theory. (orig.)

Nonstationary oscillations in gyrotrons revisited

International Nuclear Information System (INIS)

Dumbrajs, O.; Kalis, H.

2015-01-01

Development of gyrotrons requires careful understanding of different regimes of gyrotron oscillations. It is known that in the planes of the generalized gyrotron variables: cyclotron resonance mismatch and dimensionless current or cyclotron resonance mismatch and dimensionless interaction length complicated alternating sequences of regions of stationary, periodic, automodulation, and chaotic oscillations exist. In the past, these regions were investigated on the supposition that the transit time of electrons through the interaction space is much shorter than the cavity decay time. This assumption is valid for short and/or high diffraction quality resonators. However, in the case of long and/or low diffraction quality resonators, which are often utilized, this assumption is no longer valid. In such a case, a different mathematical formalism has to be used for studying nonstationary oscillations. One example of such a formalism is described in the present paper

Regulating Cortical Oscillations in an Inhibition-Stabilized Network.

Science.gov (United States)

Jadi, Monika P; Sejnowski, Terrence J

2014-04-21

Understanding the anatomical and functional architecture of the brain is essential for designing neurally inspired intelligent systems. Theoretical and empirical studies suggest a role for narrowband oscillations in shaping the functional architecture of the brain through their role in coding and communication of information. Such oscillations are ubiquitous signals in the electrical activity recorded from the brain. In the cortex, oscillations detected in the gamma range (30-80 Hz) are modulated by behavioral states and sensory features in complex ways. How is this regulation achieved? Although several underlying principles for the genesis of these oscillations have been proposed, a unifying account for their regulation has remained elusive. In a network of excitatory and inhibitory neurons operating in an inhibition-stabilized regime, we show that strongly superlinear responses of inhibitory neurons facilitate bidirectional regulation of oscillation frequency and power. In such a network, the balance of drives to the excitatory and inhibitory populations determines how the power and frequency of oscillations are modulated. The model accounts for the puzzling increase in their frequency with the salience of visual stimuli, and a decrease with their size. Oscillations in our model grow stronger as the mean firing level is reduced, accounting for the size dependence of visually evoked gamma rhythms, and suggesting a role for oscillations in improving the signal-to-noise ratio (SNR) of signals in the brain. Empirically testing such predictions is still challenging, and implementing the proposed coding and communication strategies in neuromorphic systems could assist in our understanding of the biological system.

OSCILLATING MODE OF TOPINAMBUR TUBERS DRYING

Directory of Open Access Journals (Sweden)

A. V. Golubkivich

2015-01-01

Full Text Available Specifics of a chemical composition of tubers and green material of a topinambur (Helianthus tuberosus, high efficiency and ecological plasticity, profitability of growing, biotechnological potential of use enable to identify a topinambur as a of high-energy cultures of the future. High moisture of various topinambur parts, features of the mechanism of a heat and mass transfer set a problem of search of the new drying methods promoting to increase dehydration efficiency and produce a quality product. A method of calculation of duration of the oscillating mode of topinambur tubers drying in a dense layer is worked out. The topinambur tubers cut on cubes with the side of 6 mm were taken as object of researches. Researches were conducted in the setting of various drying modes: two experiences at the oscillating mode with height of a material layer of 0.07 m and 0.17 m; and also as a check experiment was material drying at a constant temperature of the drying agent. Duration of the oscillating mode of topinambur tubers drying was calculated on their basis of received curves of changes of moisture content at various modes of drying. Estimate indicators were confirmed with experimental data. Results of determination of duration of the oscillating modes of topinambur tubers drying proved that efficiency of the oscillating modes is 18 percent higher, than at control experiment.

Resonant Spin-Transfer-Torque Nano-Oscillators

Science.gov (United States)

Sharma, Abhishek; Tulapurkar, Ashwin A.; Muralidharan, Bhaskaran

2017-12-01

Spin-transfer-torque nano-oscillators are potential candidates for replacing the traditional inductor-based voltage-controlled oscillators in modern communication devices. Typical oscillator designs are based on trilayer magnetic tunnel junctions, which have the disadvantages of low power outputs and poor conversion efficiencies. We theoretically propose using resonant spin filtering in pentalayer magnetic tunnel junctions as a possible route to alleviate these issues and present viable device designs geared toward a high microwave output power and an efficient conversion of the dc input power. We attribute these robust qualities to the resulting nontrivial spin-current profiles and the ultrahigh tunnel magnetoresistance, both of which arise from resonant spin filtering. The device designs are based on the nonequilibrium Green's-function spin-transport formalism self-consistently coupled with the stochastic Landau-Lifshitz-Gilbert-Slonczewski equation and Poisson's equation. We demonstrate that the proposed structures facilitate oscillator designs featuring a large enhancement in microwave power of around 1150% and an efficiency enhancement of over 1100% compared to typical trilayer designs. We rationalize the optimum operating regions via an analysis of the dynamic and static device resistances. We also demonstrate the robustness of our structures against device design fluctuations and elastic dephasing. This work sets the stage for pentalyer spin-transfer-torque nano-oscillator device designs that ameliorate major issues associated with typical trilayer designs.

Antineutrino Oscillations in the Atmospheric Sector

Energy Technology Data Exchange (ETDEWEB)

Himmel, Alexander I. [California Inst. of Technology (CalTech), Pasadena, CA (United States)

2011-05-01

This thesis presents measurements of the oscillations of muon antineutrinos in the atmospheric sector, where world knowledge of antineutrino oscillations lags well behind the knowledge of neutrinos, as well as a search for v_μ → $\\bar{v}$_μ transitions. Differences between neutrino and antineutrino oscillations could be a sign of physics beyond the Standard Model, including non-standard matter interactions or the violation of CPT symmetry. These measurements leverage the sign-selecting capabilities of the magnetized steel-scintillator MINOS detectors to analyze antineutrinos from the NuMI beam, both when it is in neutrino-mode and when it is in antineutrino-mode. Antineutrino oscillations are observed at |Δ$\\bar{m}$_atm ²| = (3.36_-0.40^+0.46(stat) ± 0.06(syst)) x 10^-3 eV² and sin²(2$\\bar{θ}$₂₃) = 0.860_-0.12^+0.11(stat) ± 0.01(syst). The oscillation parameters measured for antineutrinos and those measured by MINOS for neutrinos differ by a large enough margin that the chance of obtaining two values as discrepant as those observed is only 2%, assuming the two measurements arise from the same underlying mechanism, with the same parameter values. No evidence is seen for neutrino-to-antineutrino transitions.

Global competition and local cooperation in a network of neural oscillators

Science.gov (United States)

Terman, David; Wang, DeLiang

An architecture of locally excitatory, globally inhibitory oscillator networks is proposed and investigated both analytically and by computer simulation. The model for each oscillator corresponds to a standard relaxation oscillator with two time scales. Oscillators are locally coupled by a scheme that resembles excitatory synaptic coupling, and each oscillator also inhibits other oscillators through a common inhibitor. Oscillators are driven to be oscillatory by external stimulation. The network exhibits a mechanism of selective gating, whereby an oscillator jumping up to its active phase rapidly recruits the oscillators stimulated by the same pattern, while preventing the other oscillators from jumping up. We show analytically that with the selective gating mechanism, the network rapidly achieves both synchronization within blocks of oscillators that are stimulated by connected regions and desynchronization between different blocks. Computer simulations demonstrate the model's promising ability for segmenting multiple input patterns in real time. This model lays a physical foundation for the oscillatory correlation theory of feature binding and may provide an effective computational framework for scene segmentation and figure/ ground segregation.

Molecular dynamics simulation of square graphene-nanoflake oscillator on graphene nanoribbon.

Science.gov (United States)

Kang, Jeong Won; Lee, Kang Whan

2014-12-01

Graphene nanoflakes (GNFs) have been of interest for a building block in order to develop electromechanical devices on a nanometer scale. Here, we present the oscillation motions of a square GNF oscillator on graphene nanoribbon (GNR) in the retracting-motions by performing classical molecular dynamics simulations. The simulation results showed that the GNF oscillators can be considered as a building block for nanoelectromechanical systems such as carbon-nanotube (CNT) oscillators. The oscillation dynamics of the GNF oscillator were similar to those of the CNT oscillators. When the square GNF had an initial velocity as impulse dynamics, its oscillation motions on the GNR were achieved from its self-retracting van der Waals force. For low initial velocity, its translational motions were dominant in its motions rather than its rotational motions. The kinetic energy damping ratio rapidly decreased as initial velocity increased and the kinetic energy for the translational motion of the GNF oscillator rapidly transferred into that for its rotational motion. The oscillation frequency of the GNF oscillator was dependent on its initial velocity.

Klein-Gordon oscillators in noncommutative phase space

International Nuclear Information System (INIS)

Wang Jianhua

2008-01-01

We study the Klein-Gordon oscillators in non-commutative (NC) phase space. We find that the Klein-Gordon oscillators in NC space and NC phase-space have a similar behaviour to the dynamics of a particle in commutative space moving in a uniform magnetic field. By solving the Klein-Gordon equation in NC phase space, we obtain the energy levels of the Klein-Gordon oscillators, where the additional terms related to the space-space and momentum-momentum non-commutativity are given explicitly. (authors)

Electrochemical Oscillation of Vanadium Ions in Anolyte

Directory of Open Access Journals (Sweden)

Hao Peng

2017-08-01

Full Text Available Periodic electrochemical oscillation of the anolyte was reported for the first time in a simulated charging process of the vanadium redox flow batteries. The electrochemical oscillation could be explained in terms of the competition between the growth and the chemical dissolution of V2O5 film. Also, the oscillation phenomenon was possible to regular extra power consumption. The results of this paper might enable new methods to improve the charge efficiency and energy saving for vanadium redox flow batteries.

Solar Dynamo Driven by Periodic Flow Oscillation

Science.gov (United States)

Mayr, Hans G.; Hartle, Richard E.; Einaudi, Franco (Technical Monitor)

2001-01-01

We have proposed that the periodicity of the solar magnetic cycle is determined by wave mean flow interactions analogous to those driving the Quasi Biennial Oscillation in the Earth's atmosphere. Upward propagating gravity waves would produce oscillating flows near the top of the radiation zone that in turn would drive a kinematic dynamo to generate the 22-year solar magnetic cycle. The dynamo we propose is built on a given time independent magnetic field B, which allows us to estimate the time dependent, oscillating components of the magnetic field, (Delta)B. The toroidal magnetic field (Delta)B(sub phi) is directly driven by zonal flow and is relatively large in the source region, (Delta)(sub phi)/B(sub Theta) much greater than 1. Consistent with observations, this field peaks at low latitudes and has opposite polarities in both hemispheres. The oscillating poloidal magnetic field component, (Delta)B(sub Theta), is driven by the meridional circulation, which is difficult to assess without a numerical model that properly accounts for the solar atmosphere dynamics. Scale-analysis suggests that (Delta)B(sub Theta) is small compared to B(sub Theta) in the dynamo region. Relative to B(sub Theta), however, the oscillating magnetic field perturbations are expected to be transported more rapidly upwards in the convection zone to the solar surface. As a result, (Delta)B(sub Theta) (and (Delta)B(sub phi)) should grow relative to B(sub Theta), so that the magnetic fields reverse at the surface as observed. Since the meridional and zonai flow oscillations are out of phase, the poloidal magnetic field peaks during times when the toroidal field reverses direction, which is observed. With the proposed wave driven flow oscillation, the magnitude of the oscillating poloidal magnetic field increases with the mean rotation rate of the fluid. This is consistent with the Bode-Blackett empirical scaling law, which reveals that in massive astrophysical bodies the magnetic moment tends

Sectorial oscillation of acoustically levitated nanoparticle-coated droplet

Science.gov (United States)

Zang, Duyang; Chen, Zhen; Geng, Xingguo

2016-01-01

We have investigated the dynamics of a third mode sectorial oscillation of nanoparticle-coated droplets using acoustic levitation in combination with active modulation. The presence of nanoparticles at the droplet surface changes its oscillation amplitude and frequency. A model linking the interfacial rheology and oscillation dynamics has been proposed in which the compression modulus ɛ of the particle layer is introduced into the analysis. The ɛ obtained with the model is in good agreement with that obtained by the Wilhelmy plate approach, highlighting the important role of interfacial rheological properties in the sectorial oscillation of droplets.

Experimental study of a premixed oscillating flame stabilized inside the tube

Energy Technology Data Exchange (ETDEWEB)

Choi, B.I.; Shin, H.D. [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

1998-04-01

An experimental study of premixed oscillating flame stabilized inside the tube has been conducted in order to examine the kinematic behavior of premixed flame under the flow oscillation and flame/flow interaction. Flow oscillation is accomplished by an acoustic excitation. Oscillating nature of flow has been studied with and without the flame using velocity and pressure measurements by a LDV and microphone, respectively Kinematic behavior of the oscillating flame is examined using triggered ICCD camera system. Velocity oscillation and flame oscillation is the same frequency as that produced by the acoustic excitation and flame shape has a similarity at various phase of oscillation. Upstream velocity field near the flame zone is greatly influenced by the flame oscillation. This is the typical example of flame/flow interaction. (author). 9 refs., 7 figs.

A simple approach to nonlinear oscillators

International Nuclear Information System (INIS)

Ren Zhongfu; He Jihuan

2009-01-01

A very simple and effective approach to nonlinear oscillators is suggested. Anyone with basic knowledge of advanced calculus can apply the method to finding approximately the amplitude-frequency relationship of a nonlinear oscillator. Some examples are given to illustrate its extremely simple solution procedure and an acceptable accuracy of the obtained solutions.

Golden quantum oscillator and Binet–Fibonacci calculus

International Nuclear Information System (INIS)

Pashaev, Oktay K; Nalci, Sengul

2012-01-01

The Binet formula for Fibonacci numbers is treated as a q-number and a q-operator with Golden ratio bases q = φ and Q = −1/φ, and the corresponding Fibonacci or Golden calculus is developed. A quantum harmonic oscillator for this Golden calculus is derived so that its spectrum is given only by Fibonacci numbers. The ratio of successive energy levels is found to be the Golden sequence, and for asymptotic states in the limit n → ∞ it appears as the Golden ratio. We call this oscillator the Golden oscillator. Using double Golden bosons, the Golden angular momentum and its representation in terms of Fibonacci numbers and the Golden ratio are derived. Relations of Fibonacci calculus with a q-deformed fermion oscillator and entangled N-qubit states are indicated. (paper)

High power RF oscillator with Marx generators

International Nuclear Information System (INIS)

Murase, Hiroshi; Hayashi, Izumi

1980-01-01

A method to maintain RF oscillation by using many Marx generators was proposed and studied experimentally. Many charging circuits were connected to an oscillator circuit, and successive pulsed charging was made. This successive charging amplified and maintained the RF oscillation. The use of vacuum gaps and high power silicon diodes improved the characteristics of RF current cut-off of the circuit. The efficiency of the pulsed charging from Marx generators to a condenser was theoretically investigated. The theoretical result showed the maximum efficiency of 0.98. The practical efficiency obtained by using a proposed circuit with a high power oscillator was in the range 0.50 to 0.56. The obtained effective output power of the RF pulses was 11 MW. The maximum holding time of the RF pulses was about 21 microsecond. (Kato, T.)

Golden quantum oscillator and Binet-Fibonacci calculus

Energy Technology Data Exchange (ETDEWEB)

Pashaev, Oktay K; Nalci, Sengul, E-mail: oktaypashaev@iyte.edu.tr [Department of Mathematics, Izmir Institute of Technology, Urla-Izmir 35430 (Turkey)

2012-01-13

The Binet formula for Fibonacci numbers is treated as a q-number and a q-operator with Golden ratio bases q = {phi} and Q = -1/{phi}, and the corresponding Fibonacci or Golden calculus is developed. A quantum harmonic oscillator for this Golden calculus is derived so that its spectrum is given only by Fibonacci numbers. The ratio of successive energy levels is found to be the Golden sequence, and for asymptotic states in the limit n {yields} {infinity} it appears as the Golden ratio. We call this oscillator the Golden oscillator. Using double Golden bosons, the Golden angular momentum and its representation in terms of Fibonacci numbers and the Golden ratio are derived. Relations of Fibonacci calculus with a q-deformed fermion oscillator and entangled N-qubit states are indicated. (paper)

Photospheric Origin of Three-minute Oscillations in a Sunspot

Energy Technology Data Exchange (ETDEWEB)

Chae, Jongchul; Lee, Jeongwoo; Cho, Kyuhyoun; Song, Donguk [Astronomy Program, Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826 (Korea, Republic of); Cho, Kyungsuk; Yurchyshyn, Vasyl [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055 (Korea, Republic of)

2017-02-10

The origin of the three-minute oscillations of intensity and velocity observed in the chromosphere of sunspot umbrae is still unclear. We investigated the spatio-spectral properties of the 3 minute oscillations of velocity in the photosphere of a sunspot umbra as well as those in the low chromosphere using the spectral data of the Ni i λ 5436, Fe i λ 5435, and Na i D{sub 2} λ 5890 lines taken by the Fast Imaging Solar Spectrograph of the 1.6 m New Solar Telescope at the Big Bear Solar Observatory. As a result, we found a local enhancement of the 3 minute oscillation power in the vicinities of a light bridge (LB) and numerous umbral dots (UDs) in the photosphere. These 3 minute oscillations occurred independently of the 5 minute oscillations. Through wavelet analysis, we determined the amplitudes and phases of the 3 minute oscillations at the formation heights of the spectral lines, and they were found to be consistent with the upwardly propagating slow magnetoacoustic waves in the photosphere with energy flux large enough to explain the chromospheric oscillations. Our results suggest that the 3 minute chromospheric oscillations in this sunspot may have been generated by magnetoconvection occurring in the LB and UDs.

Non-linear phenomena in electronic systems consisting of coupled single-electron oscillators

International Nuclear Information System (INIS)

Kikombo, Andrew Kilinga; Hirose, Tetsuya; Asai, Tetsuya; Amemiya, Yoshihito

2008-01-01

This paper describes non-linear dynamics of electronic systems consisting of single-electron oscillators. A single-electron oscillator is a circuit made up of a tunneling junction and a resistor, and produces simple relaxation oscillation. Coupled with another, single electron oscillators exhibit complex behavior described by a combination of continuous differential equations and discrete difference equations. Computer simulation shows that a double-oscillator system consisting of two coupled oscillators produces multi-periodic oscillation with a single attractor, and that a quadruple-oscillator system consisting of four oscillators also produces multi-periodic oscillation but has a number of possible attractors and takes one of them determined by initial conditions

The algebra of two dimensional generalized Chebyshev-Koornwinder oscillator

International Nuclear Information System (INIS)

Borzov, V. V.; Damaskinsky, E. V.

2014-01-01

In the previous works of Borzov and Damaskinsky [“Chebyshev-Koornwinder oscillator,” Theor. Math. Phys. 175(3), 765–772 (2013)] and [“Ladder operators for Chebyshev-Koornwinder oscillator,” in Proceedings of the Days on Diffraction, 2013], the authors have defined the oscillator-like system that is associated with the two variable Chebyshev-Koornwinder polynomials. We call this system the generalized Chebyshev-Koornwinder oscillator. In this paper, we study the properties of infinite-dimensional Lie algebra that is analogous to the Heisenberg algebra for the Chebyshev-Koornwinder oscillator. We construct the exact irreducible representation of this algebra in a Hilbert space H of functions that are defined on a region which is bounded by the Steiner hypocycloid. The functions are square-integrable with respect to the orthogonality measure for the Chebyshev-Koornwinder polynomials and these polynomials form an orthonormalized basis in the space H. The generalized oscillator which is studied in the work can be considered as the simplest nontrivial example of multiboson quantum system that is composed of three interacting oscillators

Generalized oscillator systems and their parabosonic interpretation

Energy Technology Data Exchange (ETDEWEB)

Macfarlane, A J [Cambridge Univ. (United Kingdom). Dept. of Applied Mathematics and Theoretical Physics

1994-12-31

The Fock space description of various bosonic oscillator systems are carried out. All descriptions are based on a single creation - annihilation pair. Special attention is paid to the q-deformed Calogero-Vasiliev oscillator. 23 refs.

Temporal structure of neuronal population oscillations with empirical model decomposition

International Nuclear Information System (INIS)

Li Xiaoli

2006-01-01

Frequency analysis of neuronal oscillation is very important for understanding the neural information processing and mechanism of disorder in the brain. This Letter addresses a new method to analyze the neuronal population oscillations with empirical mode decomposition (EMD). Following EMD of neuronal oscillation, a series of intrinsic mode functions (IMFs) are obtained, then Hilbert transform of IMFs can be used to extract the instantaneous time frequency structure of neuronal oscillation. The method is applied to analyze the neuronal oscillation in the hippocampus of epileptic rats in vivo, the results show the neuronal oscillations have different descriptions during the pre-ictal, seizure onset and ictal periods of the epileptic EEG at the different frequency band. This new method is very helpful to provide a view for the temporal structure of neural oscillation

Studies on the rare earth complexes with pyridine derivatives and their N-oxide(II) - Synthesis and properties of fluorescent solid complexes of samarium, europium, gadolium and terbium chlorides with 2,2'-bipyridine-N,N'-dioxide

International Nuclear Information System (INIS)

Minyu, T.; Ning, T.; Yingli, Z.; Jiyuan, B.

1985-01-01

The solid complexes of rare earth nitrates perchlorates and thiocyanates with 2,2'-bipyridine-N,N'-dioxide (bipyO/sub 2/) have been reported. However, the corresponding complexes of other rear earth chlorides have not been investigated except lanthanum, cerium and yttrium. As an extension of our previous work on the synthesis of complexes of praseodymium and neodymium chlorides wiht bipoyO/sub 2/, the authors have now prepared fluorescent solid complexes of samarium, europium, gadolium and terbium chlorides with biphyO/sub 2/, using methanol as a reaction medium. The new synthesized compounds have been identified by means of elemental analysis, infrared spectrometry, conductometry, differential thermal analysis (DTA), thermogravimetry (TG) and X-ray powder diffraction

Basin stability measure of different steady states in coupled oscillators

Science.gov (United States)

Rakshit, Sarbendu; Bera, Bidesh K.; Majhi, Soumen; Hens, Chittaranjan; Ghosh, Dibakar

2017-04-01

In this report, we investigate the stabilization of saddle fixed points in coupled oscillators where individual oscillators exhibit the saddle fixed points. The coupled oscillators may have two structurally different types of suppressed states, namely amplitude death and oscillation death. The stabilization of saddle equilibrium point refers to the amplitude death state where oscillations are ceased and all the oscillators converge to the single stable steady state via inverse pitchfork bifurcation. Due to multistability features of oscillation death states, linear stability theory fails to analyze the stability of such states analytically, so we quantify all the states by basin stability measurement which is an universal nonlocal nonlinear concept and it interplays with the volume of basins of attractions. We also observe multi-clustered oscillation death states in a random network and measure them using basin stability framework. To explore such phenomena we choose a network of coupled Duffing-Holmes and Lorenz oscillators which are interacting through mean-field coupling. We investigate how basin stability for different steady states depends on mean-field density and coupling strength. We also analytically derive stability conditions for different steady states and confirm by rigorous bifurcation analysis.

Chimera and phase-cluster states in populations of coupled chemical oscillators

Science.gov (United States)

Tinsley, Mark R.; Nkomo, Simbarashe; Showalter, Kenneth

2012-09-01

Populations of coupled oscillators may exhibit two coexisting subpopulations, one with synchronized oscillations and the other with unsynchronized oscillations, even though all of the oscillators are coupled to each other in an equivalent manner. This phenomenon, discovered about ten years ago in theoretical studies, was then further characterized and named the chimera state after the Greek mythological creature made up of different animals. The highly counterintuitive coexistence of coherent and incoherent oscillations in populations of identical oscillators, each with an equivalent coupling structure, inspired great interest and a flurry of theoretical activity. Here we report on experimental studies of chimera states and their relation to other synchronization states in populations of coupled chemical oscillators. Our experiments with coupled Belousov-Zhabotinsky oscillators and corresponding simulations reveal chimera behaviour that differs significantly from the behaviour found in theoretical studies of phase-oscillator models.

Oscillating neutrinos from the Galactic center

International Nuclear Information System (INIS)

Crocker, R.M.; Volkas, R.R.; Melia, F.

1999-11-01

It has recently been demonstrated that the γ-ray emission spectrum of the EGRET-identified, central Galactic source 2EG J1746-2852 can be well fitted by positing that these photons are generated by the decay of π 0, s produced in p-p scattering at or near an energizing shock. Such scattering also produces charged pions which decay leptonically. The ratio of γ-rays to neutrinos generated by the central Galactic source may be accurately determined and a well-defined and potentially-measurable high energy neutrino flux at Earth is unavoidable. An opportunity, therefore, to detect neutrino oscillations over an unprecedented scale is offered by this source. In this paper we assess the prospects for such an observation with the generation of neutrino Cerenkov telescopes now in the planning stage. We determine that the next generation of detectors may find an oscillation signature in the Galactic Center (GC) signal, but that such an observation will probably not further constrain the oscillation parameter space mapped out by current atmospheric, solar, reactor and accelerator neutrino oscillation experiments

Invariant box-parameterization of neutrino oscillations

International Nuclear Information System (INIS)

Weiler, Thomas J.; Wagner, DJ

1998-01-01

The model-independent 'box' parameterization of neutrino oscillations is examined. The invariant boxes are the classical amplitudes of the individual oscillating terms. Being observables, the boxes are independent of the choice of parameterization of the mixing matrix. Emphasis is placed on the relations among the box parameters due to mixing-matrix unitarity, and on the reduction of the number of boxes to the minimum basis set. Using the box algebra, we show that CP-violation may be inferred from measurements of neutrino flavor mixing even when the oscillatory factors have averaged. General analyses of neutrino oscillations among n≥3 flavors can readily determine the boxes, which can then be manipulated to yield magnitudes of mixing matrix elements

David Shoenberg and the beauty of quantum oscillations

Science.gov (United States)

Pudalov, V. M.

2011-01-01

The quantum oscillation effect was discovered in Leiden in 1930, by W. J. de Haas and P. M. van Alphen when measuring magnetization, and by L. W. Shubnikov and de Haas when measuring magnetoresistance. Studying single crystals of bismuth, they observed oscillatory variations in the magnetization and magnetoresistance with magnetic field. Shoenberg, whose first research in Cambridge had been on bismuth, found that much stronger oscillations are observed when a bismuth sample is cooled to liquid helium temperature rather than liquid hydrogen, which had been used by de Haas. In 1938 Shoenberg went from Cambridge to Moscow to study these oscillations at Kapitza's Institute where liquid helium was available at that time. In 1947, J. Marcus observed similar oscillations in zinc and that persuaded Schoenberg to return to this research. After that, the dHvA effect became one of his main research topics. In particular, he developed techniques for quantitative measurement of this effect in many metals. A theoretical explanation of quantum oscillations was given by L. Onsager in 1952, and an analytical quantitative theory by I. M. Lifshitz and A. M. Kosevich in 1955. These theoretical advances seemed to provide a comprehensive description of the effect. Since then, quantum oscillations have been widely used as a tool for measuring Fermi surface extremal cross-sections and all-angle electron scattering times. In his pioneering experiments of the 1960's, Shoenberg revealed the richness and deep essence of the quantum oscillation effect and showed how the beauty of the effect is disclosed under nonlinear conditions imposed by interactions in the system under study. It was quite surprising that "magnetic interaction" conditions could cause the apparently weak quantum oscillation effect to have such strong consequences as breaking the sample into magnetic (now called "Shoenberg") domains and forming an inhomogeneous magnetic state. With his contributions to the field of quantum

David Schoenberg and the beauty of quantum oscillations

International Nuclear Information System (INIS)

Pudalov, V.M.

2012-01-01

The quantum oscillation effect was discovered in Leiden, in 1930, by W.J. de Haas and P.M. van Alphen in magnetization measurement, and by L.W. Shubnikov and de Haas - in magnetoresistance. Studying single crystals of bismuth, they observed oscillatory variations of magnetization and magnetoresistance with magnetic field. Shoenberg, whose first research in Cambridge had been on bismuth, found that much stronger oscillations are observed when a bismuth sample is cooled to liquid helium rather than to liquid hydrogen, which had been used by de Haas. In 1938 Shoenberg came from Cambridge to Moscow to study these oscillations at Kapitza Institute where liquid helium was available at that time. In 1947, J. Marcus observed similar oscillations in zinc, that persuaded Shoenberg to return to this research, and, since then, the dHvA effect had been one of his main research topic. In particular, he developed techniques for quantitative measurements of the effect in many metals. Theoretical explanation of quantum oscillations was given by L. Onsager in 1952, and the analytical quantitative theory by I.M. Lifshitz and A.M. Kosevich in 1955. These theoretical advancements seemed to provide a comprehensive description of the effect. Since then, quantum oscillations were commonly considered as a tool for measuring Fermi surface extremal cross-sections and all-angle electron scattering times. However, in his pioneering experiments in 1960s, Shoenberg revealed the richness and deep essence of the quantum oscillation effect and showed how the beauty of the effect is disclosed under nonlinear conditions imposed by interactions in the system under study. It was quite unexpected, that under 'magnetic interaction' conditions, the apparently weak effect of quantum oscillations may lead to such strong consequences as breaking the sample into magnetic (now called 'Shoenberg') domains and the formation of an inhomogeneous magnetic state. Owing to his contribution to the field of quantum

Accelerator-based neutrino oscillation searches

International Nuclear Information System (INIS)

Whitehouse, D.A.; Rameika, R.; Stanton, N.

1993-01-01

This paper attempts to summarize the neutrino oscillation section of the Workshop on Future Directions in Particle and Nuclear Physics at Multi-GeV Hadron Beam Facilities. There were very lively discussions about the merits of the different oscillation channels, experiments, and facilities, but we believe a substantial consensus emerged. First, the next decade is one of great potential for discovery in neutrino physics, but it is also one of great peril. The possibility that neutrino oscillations explain the solar neutrino and atmospheric neutrino experiments, and the indirect evidence that Hot Dark Matter (HDM) in the form of light neutrinos might make up 30% of the mass of the universe, point to areas where accelerator-based experiments could play a crucial role in piecing together the puzzle. At the same time, the field faces a very uncertain future. The LSND experiment at LAMPF is the only funded neutrino oscillation experiment in the United States and it is threatened by the abrupt shutdown of LAMPF proposed for fiscal 1994. The future of neutrino physics at the Brookhaven National Laboratory AGS depends the continuation of High Energy Physics (HEP) funding after the RHIC startup. Most proposed neutrino oscillation searches at Fermilab depend on the completion of the Main Injector project and on the construction of a new neutrino beamline, which is uncertain at this point. The proposed KAON facility at TRIUMF would provide a neutrino beam similar to that at the AGS but with a much increase intensity. The future of KAON is also uncertain. Despite the difficult obstacles present, there is a real possibility that we are on the verge of understanding the masses and mixings of the neutrinos. The physics importance of such a discovery can not be overstated. The current experimental status and future possibilities are discussed below

Xenon oscillation tests in four-loop PWR cores

International Nuclear Information System (INIS)

Aoki, Norihiko; Osaka, Kenichi; Shimada, Shoichiro; Tochihara, Hiroshi; Machii, Seigo

1980-01-01

The Kansai Electric Power Co.'s OHI Unit 1 and 2 are the first 4-loop PWRs in Japan which use 17 x 17 fuel assemblies and have essentially the same plant parameters. A 4-loop core has larger core radius and higher power density than those of 2- or 3-loop cores, and is less stable for Xe oscillation. It is therefore important to confirm that Xe oscillations in radial direction are sufficiently stable in a 4-loop core. Radial and axial Xe oscillation tests were performed during the startup physics tests of OHI Unit 1 and 2; Xe oscillation was induced by perturbation of control rods and the Xe effect on power distribution observed periodically. The test results show that the transverse Xe oscillation in the 4-loop core is sufficiently stable and that the agreement between the measurement and the calculated prediction is good. (author)

Neutrino oscillations in discrete-time quantum walk framework

Energy Technology Data Exchange (ETDEWEB)

Mallick, Arindam; Mandal, Sanjoy; Chandrashekar, C.M. [C. I. T. Campus, The Institute of Mathematical Sciences, Chennai (India); Homi Bhabha National Institute, Training School Complex, Mumbai (India)

2017-02-15

Here we present neutrino oscillation in the framework of quantum walks. Starting from a one spatial dimensional discrete-time quantum walk we present a scheme of evolutions that will simulate neutrino oscillation. The set of quantum walk parameters which is required to reproduce the oscillation probability profile obtained in both, long range and short range neutrino experiment is explicitly presented. Our scheme to simulate three-generation neutrino oscillation from quantum walk evolution operators can be physically realized in any low energy experimental set-up with access to control a single six-level system, a multiparticle three-qubit or a qubit-qutrit system. We also present the entanglement between spins and position space, during neutrino propagation that will quantify the wave function delocalization around instantaneous average position of the neutrino. This work will contribute towards understanding neutrino oscillation in the framework of the quantum information perspective. (orig.)

Power spectrum of an injection-locked Josephson oscillator

International Nuclear Information System (INIS)

Stancampiano, C.V.; Shapiro, S.

1975-01-01

Experiments have shown that a Josephson oscillator, exposed to a weak narrow-band input signal, exhibits behavior characteristic of an injection-locked oscillator. When in lock, Adler's theory of injection locking describes the experimental observations reasonably well. The range of applicability of the theory is extended to the out-of-lock regime where a spectrum of output frequencies is observed. Obtaining the theoretical output power spectrum requires solving a differential equation having the same form as the equation describing the resistively shunted junction model of Stewart and of McCumber. Experimental measurements of the output spectrum of a nearly locked Josephson oscillator are shown to be in reasonable agreement with the theory. Additional results discussed briefly include the observation of a frequency dependence of the locked Josephson oscillator output and experiments in which a Josephson oscillator-mixer was injection locked by a weak signal at the rf

Oscillation characteristics of the reactor 'A'; Oscilatorne karakteristike reaktora 'A'

Energy Technology Data Exchange (ETDEWEB)

Zecevic, V; Lolic, B [The Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

1961-07-01

In addition to good knowledge of reactor physical properties, design of the reactor oscillator demands determining of the oscillator operating points as well as oscillation reactor properties. This paper contains study of the RA reactor power changes due to oscillations in in one of the vertical experimental channels. It has been concluded that the reactor optimum operating conditions are attained when the oscillator operates at optimum points, and other parameters are determined dependent on the sensitivity of the method and reactor stability.

Mass and oscillations of Dirac neutrinos

International Nuclear Information System (INIS)

Collot, J.

1989-01-01

In the most economical extension of the standard model, we have presented the theory of massive Dirac neutrinos. We have particularly emphasized that, in this model, a complete analogy between quarks and leptons can be erected and predicts neutrino flavor oscillations. We have reviewed the last experimental results concerning kinetic neutrino mass experiments and neutrino oscillation investigations

Sun oscillations and the problem of its internal structure

International Nuclear Information System (INIS)

Severnyj, A.B.; Kotov, V.A.; Tsap, T.T.

1979-01-01

Analysis of global solar oscillation measurements for five years (1974-1978, more than 1000 hours of observations, 215 days) is given. It is shown that the period of oscillations is 160sup(m)x0.10+-0sup(m)x004 and the amplitude is 1 m/s. The phases of oscillations, obtained at the Crimea, Stanford, Kitt Peak and Pic du Midi, are in good agreement, thus making the assumption on ''telluric origin'' of the oscillations improbable. It has been found: 1) slow, synchronous (at Crimea and Stanford) drift of the phase of velocity maximum from year to year and 2) the dependence of amplitude on the phase of 27-day rotational period of the Sun which favours the assumption on the quadrupole character of oscillations. It is pointed out that these facts, as well as the absence of oscillation waves in the telluric line observed simultaneously with the solar line, exclude the possibility of explaining the results as a statistical artifact. It has also been shown that the differential extinction effect produces an oscillation effect which is by an order of magnitude lower than the observed one. The following preliminary results are noted: a) the appearance of synchronous oscillations of the mean solar magnetic field of the brightness of the Sun and of the solar radio emission; b) the disappearance of the oscillations from time to time, possibly due to the effect of the supergranulation passage across the solar disk. The oscillations observed imply new important restrictions on the problem of the internal constitution of the Sun, and point to the possibility of non-radiative heat-transfer inside the Sun which might help the solution of the low neutrino flux problem

Chemical event chain model of coupled genetic oscillators.

Science.gov (United States)

Jörg, David J; Morelli, Luis G; Jülicher, Frank

2018-03-01

We introduce a stochastic model of coupled genetic oscillators in which chains of chemical events involved in gene regulation and expression are represented as sequences of Poisson processes. We characterize steady states by their frequency, their quality factor, and their synchrony by the oscillator cross correlation. The steady state is determined by coupling and exhibits stochastic transitions between different modes. The interplay of stochasticity and nonlinearity leads to isolated regions in parameter space in which the coupled system works best as a biological pacemaker. Key features of the stochastic oscillations can be captured by an effective model for phase oscillators that are coupled by signals with distributed delays.

Chemical event chain model of coupled genetic oscillators

Science.gov (United States)

Jörg, David J.; Morelli, Luis G.; Jülicher, Frank

2018-03-01

We introduce a stochastic model of coupled genetic oscillators in which chains of chemical events involved in gene regulation and expression are represented as sequences of Poisson processes. We characterize steady states by their frequency, their quality factor, and their synchrony by the oscillator cross correlation. The steady state is determined by coupling and exhibits stochastic transitions between different modes. The interplay of stochasticity and nonlinearity leads to isolated regions in parameter space in which the coupled system works best as a biological pacemaker. Key features of the stochastic oscillations can be captured by an effective model for phase oscillators that are coupled by signals with distributed delays.

Adaptive elimination of synchronization in coupled oscillator

Science.gov (United States)

Zhou, Shijie; Ji, Peng; Zhou, Qing; Feng, Jianfeng; Kurths, Jürgen; Lin, Wei

2017-08-01

We present here an adaptive control scheme with a feedback delay to achieve elimination of synchronization in a large population of coupled and synchronized oscillators. We validate the feasibility of this scheme not only in the coupled Kuramoto’s oscillators with a unimodal or bimodal distribution of natural frequency, but also in two representative models of neuronal networks, namely, the FitzHugh-Nagumo spiking oscillators and the Hindmarsh-Rose bursting oscillators. More significantly, we analytically illustrate the feasibility of the proposed scheme with a feedback delay and reveal how the exact topological form of the bimodal natural frequency distribution influences the scheme performance. We anticipate that our developed scheme will deepen the understanding and refinement of those controllers, e.g. techniques of deep brain stimulation, which have been implemented in remedying some synchronization-induced mental disorders including Parkinson disease and epilepsy.

Adaptive elimination of synchronization in coupled oscillator

International Nuclear Information System (INIS)

Zhou, Shijie; Lin, Wei; Ji, Peng; Feng, Jianfeng; Zhou, Qing; Kurths, Jürgen

2017-01-01

We present here an adaptive control scheme with a feedback delay to achieve elimination of synchronization in a large population of coupled and synchronized oscillators. We validate the feasibility of this scheme not only in the coupled Kuramoto’s oscillators with a unimodal or bimodal distribution of natural frequency, but also in two representative models of neuronal networks, namely, the FitzHugh–Nagumo spiking oscillators and the Hindmarsh–Rose bursting oscillators. More significantly, we analytically illustrate the feasibility of the proposed scheme with a feedback delay and reveal how the exact topological form of the bimodal natural frequency distribution influences the scheme performance. We anticipate that our developed scheme will deepen the understanding and refinement of those controllers, e.g. techniques of deep brain stimulation, which have been implemented in remedying some synchronization-induced mental disorders including Parkinson disease and epilepsy. (paper)

Truly neutral microobjects and oscillations in particle physics

International Nuclear Information System (INIS)

Bilenky, S.M.; Pontecorvo, B.

1982-01-01

Oscillation phenomena between different states of neutral elementary particles are discussed. The known kaon oscillation and the proposed neutrino, neutron and other kinds of oscillations are analysed. The proper bound states of neutral objects (neutrinos, neutrons, hydrogen atoms) are investigated in the case of small and strong violation of CP symmetry. Consequences concerning the observable masses and quantum numbers of such neutral objects are drawn. (D.Gy.)

Automated Detection of Oscillating Regions in the Solar Atmosphere

Science.gov (United States)

Ireland, J.; Marsh, M. S.; Kucera, T. A.; Young, C. A.

2010-01-01

Recently observed oscillations in the solar atmosphere have been interpreted and modeled as magnetohydrodynamic wave modes. This has allowed for the estimation of parameters that are otherwise hard to derive, such as the coronal magnetic-field strength. This work crucially relies on the initial detection of the oscillations, which is commonly done manually. The volume of Solar Dynamics Observatory (SDO) data will make manual detection inefficient for detecting all of the oscillating regions. An algorithm is presented that automates the detection of areas of the solar atmosphere that support spatially extended oscillations. The algorithm identifies areas in the solar atmosphere whose oscillation content is described by a single, dominant oscillation within a user-defined frequency range. The method is based on Bayesian spectral analysis of time series and image filtering. A Bayesian approach sidesteps the need for an a-priori noise estimate to calculate rejection criteria for the observed signal, and it also provides estimates of oscillation frequency, amplitude, and noise, and the error in all of these quantities, in a self-consistent way. The algorithm also introduces the notion of quality measures to those regions for which a positive detection is claimed, allowing for simple post-detection discrimination by the user. The algorithm is demonstrated on two Transition Region and Coronal Explorer (TRACE) datasets, and comments regarding its suitability for oscillation detection in SDO are made.

Pattern recognition with simple oscillating circuits

International Nuclear Information System (INIS)

Hoelzel, R W; Krischer, K

2011-01-01

Neural network devices that inherently possess parallel computing capabilities are generally difficult to construct because of the large number of neuron-neuron connections. However, there exists a theoretical approach (Hoppensteadt and Izhikevich 1999 Phys. Rev. Lett. 82 2983) that forgoes the individual connections and uses only a global coupling: systems of weakly coupled oscillators with a time-dependent global coupling are capable of performing pattern recognition in an associative manner similar to Hopfield networks. The information is stored in the phase shifts of the individual oscillators. However, to date, even the feasibility of controlling phase shifts with this kind of coupling has not yet been established experimentally. We present an experimental realization of this neural network device. It consists of eight sinusoidal electrical van der Pol oscillators that are globally coupled through a variable resistor with the electric potential as the coupling variable. We estimate an effective value of the phase coupling strength in our experiment. For that, we derive a general approach that allows one to compare different experimental realizations with each other as well as with phase equation models. We demonstrate that individual phase shifts of oscillators can be experimentally controlled by a weak global coupling. Furthermore, supplied with a distorted input image, the oscillating network can indeed recognize the correct image out of a set of predefined patterns. It can therefore be used as the processing unit of an associative memory device.

Sum rules for neutrino oscillations

International Nuclear Information System (INIS)

Kobzarev, I.Yu.; Martemyanov, B.V.; Okun, L.B.; Schepkin, M.G.

1981-01-01

Sum rules for neutrino oscillations are obtained. The derivation of the general form of the s matrix for two stage process lsub(i)sup(-)→ν→lsub(k)sup(+-) (where lsub(i)sup(-)e, μ, tau, ... are initial leptons with flavor i and lsub(k)sup(+-) is final lepton) is presented. The consideration of two stage process lsub(i)sup(-)→ν→lsub(k)sup(+-) gives the possibility to take into account neutrino masses and to obtain the expressions for the oscillating cross sections. In the case of Dirac and left-handed Majorana neutrino is obtained the sum rule for the quantities 1/Vsub(K)σ(lsub(i)sup(-)→lsub(K)sup(+-)), (where Vsub(K) is a velocity of lsub(K)). In the left-handed Majorana neutrino case there is an additional antineutrino admixture leading to lsub(i)sup(-)→lsub(K)sup(+) process. Both components (neutrino and antineutrino) oscillate independently. The sums Σsub(K)1/Vsub(k)σ(lsub(i)sup(-) - lsub(K)sup(+-) then oscillate due to the presence of left-handed antineutrinos and right-handed neutrinos which do not take part in weak interactions. If right-handed currents are added sum rules analogous to considered above may be obtained. All conclusions are valid in the general case when CP is not conserved [ru

Oscillating acoustic streaming jet

International Nuclear Information System (INIS)

Moudjed, Brahim; Botton, Valery; Henry, Daniel; Millet, Severine; Ben Hadid, Hamda; Garandet, Jean-Paul

2014-01-01

The present paper provides the first experimental investigation of an oscillating acoustic streaming jet. The observations are performed in the far field of a 2 MHz circular plane ultrasound transducer introduced in a rectangular cavity filled with water. Measurements are made by Particle Image Velocimetry (PIV) in horizontal and vertical planes near the end of the cavity. Oscillations of the jet appear in this zone, for a sufficiently high Reynolds number, as an intermittent phenomenon on an otherwise straight jet fluctuating in intensity. The observed perturbation pattern is similar to that of former theoretical studies. This intermittently oscillatory behavior is the first step to the transition to turbulence. (authors)

Oscillators from nonlinear realizations

Science.gov (United States)

Kozyrev, N.; Krivonos, S.

2018-02-01

We construct the systems of the harmonic and Pais-Uhlenbeck oscillators, which are invariant with respect to arbitrary noncompact Lie algebras. The equations of motion of these systems can be obtained with the help of the formalism of nonlinear realizations. We prove that it is always possible to choose time and the fields within this formalism in such a way that the equations of motion become linear and, therefore, reduce to ones of ordinary harmonic and Pais-Uhlenbeck oscillators. The first-order actions, that produce these equations, can also be provided. As particular examples of this construction, we discuss the so(2, 3) and G 2(2) algebras.

Two port network analysis for three impedance based oscillators

KAUST Repository

Said, Lobna A.

2011-12-01

Two-port network representations are applied to analyze complex networks which can be dissolved into sub-networks connected in series, parallel or cascade. In this paper, the concept of two-port network has been studied for oscillators. Three impedance oscillator based on two port concept has been analyzed using different impedance structures. The effect of each structure on the oscillation condition and the frequency of oscillation have been introduced. Two different implementations using MOS and BJT have been introduced. © 2011 IEEE.

A combined treatment of neutrino decay and neutrino oscillations

International Nuclear Information System (INIS)

Lindner, Manfred; Ohlsson, Tommy; Winter, Walter

2001-01-01

Neutrino decay in vacuum has often been considered as an alternative to neutrino oscillations. Because nonzero neutrino masses imply the possibility of both neutrino decay and neutrino oscillations, we present a model-independent formal treatment of these combined scenarios. For that, we show for the example of Majoron decay that in many cases decay products are observable and may even oscillate. Furthermore, we construct a minimal scenario in which we study the physical implications of neutrino oscillations with intermediate decays

Oscillator clustering in a resource distribution chain

DEFF Research Database (Denmark)

Postnov, D.; Sosnovtseva, Olga; Mosekilde, Erik

2005-01-01

separate the inherent dynamics of the individual oscillator from the properties of the coupling network. Illustrated by examples from microbiological population dynamics, renal physiology, and electronic oscillator theory, we show how competition for primary resources in a resource distribution chain leads...

Characterizing brain oscillations in cognition and disease

NARCIS (Netherlands)

Jiang, H.

2016-01-01

It has been suggested that neuronal oscillations play a fundamental role for shaping the functional architecture of the working brain. This thesis investigates brain oscillations in rat, human healthy population and major depressive disorder (MDD) patients. A novel measurement termed

ALG-2 oscillates in subcellular localization, unitemporally with calcium oscillations

DEFF Research Database (Denmark)

la Cour, Jonas Marstrand; Mollerup, Jens; Berchtold, Martin Werner

2007-01-01

discovered that the subcellular distribution of a tagged version of ALG-2 could be directed by physiological external stimuli (including ATP, EGF, prostaglandin, histamine), which provoke intracellular Ca2+ oscillations. Cellular stimulation led to a redistribution of ALG-2 from the cytosol to a punctate...

SU(1,2) invariance in two-dimensional oscillator

Energy Technology Data Exchange (ETDEWEB)

Krivonos, Sergey [Bogoliubov Laboratory of Theoretical Physics,Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Nersessian, Armen [Yerevan State University,1 Alex Manoogian St., Yerevan, 0025 (Armenia); Tomsk Polytechnic University,Lenin Ave. 30, 634050 Tomsk (Russian Federation)

2017-02-01

Performing the Hamiltonian analysis we explicitly established the canonical equivalence of the deformed oscillator, constructed in arXiv:1607.03756, with the ordinary one. As an immediate consequence, we proved that the SU(1,2) symmetry is the dynamical symmetry of the ordinary two-dimensional oscillator. The characteristic feature of this SU(1,2) symmetry is a non-polynomial structure of its generators written in terms of the oscillator variables.

Temperature Oscillations in Loop Heat Pipes - A Revisit

Science.gov (United States)

Ku, Jentung

2018-01-01

Three types of temperature oscillation have been observed in the loop heat pipes. The first type is an ultra-high frequency temperature oscillation with a period on the order of seconds or less. This type of temperature oscillation is of little significance in spacecraft thermal control because the amplitude is in the noise level. The second type is a high frequency, low amplitude temperature oscillation with a period on the order of seconds to minutes and an amplitude on the order of one Kelvin. It is caused by the back-and-forth movement of the vapor front near the inlet or outlet of the condenser. The third type is a low frequency, high amplitude oscillation with a period on the order of hours and an amplitude on the order of tens of Kelvin. It is caused by the modulation of the net heat load into the evaporator by the attached large thermal mass which absorbs and releases energy alternately. Several papers on LHP temperature oscillation have been published. This paper presents a further study on the underlying physical processes during the LHP temperature oscillation, with an emphasis on the third type of temperature oscillation. Specifically, equations governing the thermal and hydraulic behaviors of LHP operation will be used to describe interactions among LHP components, heat source, and heat sink. The following sequence of events and their interrelationship will also be explored: 1) maxima and minima of reservoir and thermal mass temperatures; 2) the range of the vapor front movement inside the condenser; 3) rates of change of the reservoir and thermal mass temperatures; 4) the rate of heat absorption and heat release by the thermal mass and the rate of vapor front movement; and 5) inflection points of the reservoir and thermal mass temperatures.

Analysis and measurement of the stability of dual-resonator oscillators

KAUST Repository

Ghaed, Hassan

2012-01-01

This paper investigates the stability of oscillators with dual-resonating tanks. After deriving oscillator models, it is shown that contrary to prior belief, there can be only one stable oscillating state. Sufficient conditions for stable oscillating states are derived and silicon measurement results are used to prove their validity. A fully integrated transmitter for intraocular pressure sensing that leverages the dual-resonator tank is designed and fabricated based on the derived models. An unstable version of the transmitter is also demonstrated to prove the concept of instability in dual-resonator oscillators © 2012 IEEE.

Wigner distribution function for an oscillator

International Nuclear Information System (INIS)

Davies, R.W.; Davies, K.T.R.

1975-01-01

We present two new derivations of the Wigner distribution function for a simple harmonic oscillator Hamiltonian. Both methods are facilitated using a formula which expresses the Wigner function as a simple trace. The first method of derivation utilizes a modification of a theorem due to Messiah. An alternative procedure makes use of the coherent state representation of an oscillator. The Wigner distribution function gives a semiclassical joint probability for finding the system with given coordinates and momenta, and the joint probability is factorable for the special case of an oscillator. An important application of this result occurs in the theory of nuclear fission for calculating the probability distributions for the masses, kinetic energies, and vibrational energies of the fission fragments at infinite separation. (U.S.)

Neutrino oscillations with the OPERA experiment

CERN Document Server

Galati, Giuliana

2016-01-01

OPERA (Oscillation Project with Emulsion tRacking Apparatus) was a long-baseline experiment at the Gran Sasso laboratory (LNGS) designed to search for ν μ → ν τ oscillations in appearance mode. OPERA took data from 2008 to 2012 with the CNGS neutrino beam from CERN. The observation of five ν τ candidates allowed assessing the discovery of ν μ → ν τ appearance in the CNGS neutrino beam with a significance of 5 . 1 σ . The data analysis is still ongoing, with the goal of improving the sensitivity to the sterile neutrino search in the ν μ → ν τ and ν μ → ν e appearance channels and oscillation parameters with reduced statistical uncertainties. Current results will be presented and perspectives discussed.

Invariant box parameterization of neutrino oscillations

International Nuclear Information System (INIS)

Weiler, T.J.; Wagner, D.

1998-01-01

The model-independent 'box' parameterization of neutrino oscillations is examined. The invariant boxes are the classical amplitudes of the individual oscillating terms. Being observables, the boxes are independent of the choice of parameterization of the mixing matrix. Emphasis is placed on the relations among the box parameters due to mixing matrix unitarity, and on the reduction of the number of boxes to the minimum basis set. Using the box algebra, we show that CP-violation may be inferred from measurements of neutrino flavor mixing even when the oscillatory factors have averaged. General analyses of neutrino oscillations among n≥3 flavors can readily determine the boxes, which can then be manipulated to yield magnitudes of mixing matrix elements. copyright 1998 American Institute of Physics

Spontaneous low-frequency oscillations in cerebral vessels

DEFF Research Database (Denmark)

Schytz, Henrik W; Hansson, Andreas; Phillip, Dorte

2010-01-01

). Analysis of CA by measurement of spontaneous oscillations in the low-frequency spectrum in cerebral vessels might be a useful tool for assessing risk and investigating different treatment strategies in carotid artery disease (CAD) and stroke. We reviewed studies exploring spontaneous oscillations...

Neutrino oscillation experiments

International Nuclear Information System (INIS)

Camilleri, L.

1996-01-01

Neutrino oscillation experiments (ν μ →ν e and ν μ →ν τ ) currently being performed at accelerators are reviewed. Future plans for short and long base-line experiments are summarized. (author) 10 figs., 2 tabs., 29 refs

Photoacoustic microbeam-oscillator with tunable resonance direction and amplitude

Science.gov (United States)

Wu, Qingjun; Li, Fanghao; Wang, Bo; Yi, Futing; Jiang, J. Z.; Zhang, Dongxian

2018-01-01

We successfully design one photoacoustic microbeam-oscillator actuated by nanosecond laser, which exhibits tunable resonance direction and amplitude. The mechanism of laser induced oscillation is systematically analyzed. Both simulation and experimental results reveal that the laser induced acoustic wave propagates in a multi-reflected mode, resulting in resonance in the oscillator. This newly-fabricated micrometer-sized beam-oscillator has an excellent actuation function, i.e., by tuning the laser frequency, the direction and amplitude of actuation can be efficiently altered, which will have potential industrial applications.

Magnetization reversal driven by a spin torque oscillator

Energy Technology Data Exchange (ETDEWEB)

Sbiaa, R., E-mail: rachid@squ.edu.om [Department of Physics, Sultan Qaboos University, P.O. Box 36, PC 123 Muscat (Oman)

2014-09-01

Magnetization reversal of a magnetic free layer under spin transfer torque (STT) effect from a magnetic hard layer with a fixed magnetization direction and an oscillating layer is investigated. By including STT from the oscillating layer with in-plane anisotropy and orthogonal polarizer, magnetization-time dependence of free layer is determined. The results show that the frequency and amplitude of oscillations can be varied by adjusting the current density and magnetic properties. For an optimal oscillation frequency (f{sub opt}), a reduction of the switching time (t{sub 0}) of the free layer is observed. Both f{sub opt} and t{sub 0} increase with the anisotropy field of the free layer.

First Neutrino Oscillation Results from the NOvA experiment

Energy Technology Data Exchange (ETDEWEB)

Sachdev, Kanika [Fermilab

2016-11-29

NOvA is a long-baseline neutrino oscillation experiment on the NuMI muon neutrino beam at Fermilab. It consists of two functionally identical, nearly fully-active liquid-scintillator tracking calorimeters. The Near Detector (ND) at Fermilab is used to study the neutrino beam spectrum and composition before oscillations occur. The Far Detector in northern Minnesota, 810 km away, observes the oscillated beam and is used to extract the oscillation parameters. NOvA is designed to observe oscillations in two channels: disappearance channel ( ν μ → ν μ ) and ν e appearance channel ( ν μ → ν e ). This paper reports the measurements of both these channels based on the first NOvA data taken from February 16, 2014 till May 15, 2015

Fourier analysis of the parametric resonance in neutrino oscillations

International Nuclear Information System (INIS)

Koike, Masafumi; Ota, Toshihiko; Saito, Masako; Sato, Joe

2009-01-01

Parametric enhancement of the appearance probability of the neutrino oscillation under the inhomogeneous matter is studied. Fourier expansion of the matter density profile leads to a simple resonance condition and manifests that each Fourier mode modifies the energy spectrum of oscillation probability at around the corresponding energy; below the MSW resonance energy, a large-scale variation modifies the spectrum in high energies while a small-scale one does in low energies. In contrast to the simple parametric resonance, the enhancement of the oscillation probability is itself an slow oscillation as demonstrated by a numerical analysis with a single Fourier mode of the matter density. We derive an analytic solution to the evolution equation on the resonance energy, including the expression of frequency of the slow oscillation.

Detecting Friedel oscillations in ultracold Fermi gases

Science.gov (United States)

Riechers, Keno; Hueck, Klaus; Luick, Niclas; Lompe, Thomas; Moritz, Henning

2017-09-01

Investigating Friedel oscillations in ultracold gases would complement the studies performed on solid state samples with scanning-tunneling microscopes. In atomic quantum gases interactions and external potentials can be tuned freely and the inherently slower dynamics allow to access non-equilibrium dynamics following a potential or interaction quench. Here, we examine how Friedel oscillations can be observed in current ultracold gas experiments under realistic conditions. To this aim we numerically calculate the amplitude of the Friedel oscillations which are induced by a potential barrier in a 1D Fermi gas and compare it to the expected atomic and photonic shot noise in a density measurement. We find that to detect Friedel oscillations the signal from several thousand one-dimensional systems has to be averaged. However, as up to 100 parallel one-dimensional systems can be prepared in a single run with present experiments, averaging over about 100 images is sufficient.

Anomalous normal mode oscillations in semiconductor microcavities

Energy Technology Data Exchange (ETDEWEB)

Wang, H. [Univ. of Oregon, Eugene, OR (United States). Dept. of Physics; Hou, H.Q.; Hammons, B.E. [Sandia National Labs., Albuquerque, NM (United States)

1997-04-01

Semiconductor microcavities as a composite exciton-cavity system can be characterized by two normal modes. Under an impulsive excitation by a short laser pulse, optical polarizations associated with the two normal modes have a {pi} phase difference. The total induced optical polarization is then expected to exhibit a sin{sup 2}({Omega}t)-like oscillation where 2{Omega} is the normal mode splitting, reflecting a coherent energy exchange between the exciton and cavity. In this paper the authors present experimental studies of normal mode oscillations using three-pulse transient four wave mixing (FWM). The result reveals surprisingly that when the cavity is tuned far below the exciton resonance, normal mode oscillation in the polarization is cos{sup 2}({Omega}t)-like, in contrast to what is expected form the simple normal mode model. This anomalous normal mode oscillation reflects the important role of virtual excitation of electronic states in semiconductor microcavities.

Pharmacokinetics of labelled compounds with technetium-99m and samarium-153; Farmacocinetica de compuestos marcados con tecnecio-99m y samario-153

Energy Technology Data Exchange (ETDEWEB)

Borda O, L B; Torres L, M N

1997-07-01

The purpose of this investigation was to establish the different pharmacokinetics parameters of the main radiopharmaceuticals labeled with technetium-99m and samarium-153. These parameters could be subsequently used as reference to compare other products with the same use. Mathematical models and a computerized pharmacokinetic program were used to this purpose. A biodistribution study in quadruplicate and/or quintuplicate was conducted for each radiopharmaceutical, data was was obtained in injection dose percentages. The biodistribution study involved the injection of a predetermined dose of the radiopharmaceutical into animals (rats or mice), which were subsequently put away at different time intervals, removing the relevant organs. Activity in each organ was read by means of a well-type NaI scintillation counter, data obtained in activity counts was transformed into injection dose percentages. Based on these percentages, the mathematical model was constructed and the pharmacokinetic parameters were obtained using the computerized program Expo 2 v. 1, which is written in C language and works in windows. Analyzing the results obtained, we can conclude that the use of the Expo 2 v. 1 program for a bi compartmental analysis allowed us to obtain reliable pharmacokinetic parameters which describe what happens in the organism when the radiopharmaceutical passes from the central compartment to the peripheral one and vice versa.

Twin peak high-frequency quasi-periodic oscillations as a spectral imprint of dual oscillation modes of accretion tori