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Sample records for macroscopic 4-ap-sensitive kv

  1. KV7 potassium channels

    DEFF Research Database (Denmark)

    Stott, Jennifer B; Jepps, Thomas Andrew; Greenwood, Iain A

    2014-01-01

    Potassium channels are key regulators of smooth muscle tone, with increases in activity resulting in hyperpolarisation of the cell membrane, which acts to oppose vasoconstriction. Several potassium channels exist within smooth muscle, but the KV7 family of voltage-gated potassium channels have been...

  2. Power cables with extruded insulation and their accessories for rated voltages from 1 kV (Um = 1,2 kV) up to 30 kV (Um = 36 kV) : Part 2: cables for rated voltages from 6 kV (Um = 7,2 kV) up to 30 kV (Um = 36 kV)

    CERN Document Server

    International Electrotechnical Commission. Geneva

    2005-01-01

    Power cables with extruded insulation and their accessories for rated voltages from 1 kV (Um = 1,2 kV) up to 30 kV (Um = 36 kV) : Part 2: cables for rated voltages from 6 kV (Um = 7,2 kV) up to 30 kV (Um = 36 kV)

  3. Macroscopic theory of superconductors

    International Nuclear Information System (INIS)

    Carr, W.J. Jr.

    1981-01-01

    A macroscopic theory for bulk superconductors is developed in the framework of the theory for other magnetic materials, where ''magnetization'' current is separated from ''free'' current on the basis of scale. This contrasts with the usual separation into equilibrium and nonequilibrium currents. In the present approach magnetization, on a large macroscopic scale, results from the vortex current, while the Meissner current and other surface currents are surface contributions to the Maxwell j. The results are important for the development of thermodynamics in type-II superconductors. The advantage of the description developed here is that magnetization becomes a local concept and its associated magnetic field can be given physical meaning

  4. Macroscopic magnetic Self assembly

    NARCIS (Netherlands)

    Löthman, Per Arvid

    2018-01-01

    Exploring the macroscopic scale's similarities to the microscale is part and parcel of this thesis as reflected in the research question: what can we learn about the microscopic scale by studying the macroscale? Investigations of the environment in which the self-assembly takes place, and the

  5. Macroscopic Optomechanically Induced Transparency

    Science.gov (United States)

    Pate, Jacob; Castelli, Alessandro; Martinez, Luis; Thompson, Johnathon; Chiao, Ray; Sharping, Jay

    Optomechanically induced transparency (OMIT) is an effect wherein the spectrum of a cavity resonance is modified through interference between coupled excitation pathways. In this work we investigate a macroscopic, 3D microwave, superconducting radio frequency (SRF) cavity incorporating a niobium-coated, silicon-nitride membrane as the flexible boundary. The boundary supports acoustic vibrational resonances, which lead to coupling with the microwave resonances of the SRF cavity. The theoretical development and physical understanding of OMIT for our macroscopic SRF cavity is the same as that for other recently-reported OMIT systems despite vastly different optomechanical coupling factors and device sizes. Our mechanical oscillator has a coupling factor of g0 = 2 π . 1 ×10-5 Hz and is roughly 38 mm in diameter. The Q = 5 ×107 for the SRF cavity allows probing of optomechanical effects in the resolved sideband regime.

  6. Superposition and macroscopic observation

    International Nuclear Information System (INIS)

    Cartwright, N.D.

    1976-01-01

    The principle of superposition has long plagued the quantum mechanics of macroscopic bodies. In at least one well-known situation - that of measurement - quantum mechanics predicts a superposition. It is customary to try to reconcile macroscopic reality and quantum mechanics by reducing the superposition to a mixture. To establish consistency with quantum mechanics, values for the apparatus after a measurement are to be distributed in the way predicted by the superposition. The distributions observed, however, are those of the mixture. The statistical predictions of quantum mechanics, it appears, are not borne out by observation in macroscopic situations. It has been shown that, insofar as specific ergodic hypotheses apply to the apparatus after the interaction, the superposition which evolves is experimentally indistinguishable from the corresponding mixture. In this paper an idealized model of the measuring situation is presented in which this consistency can be demonstrated. It includes a simplified version of the measurement solution proposed by Daneri, Loinger, and Prosperi (1962). The model should make clear the kind of statistical evidence required to carry of this approach, and the role of the ergodic hypotheses assumed. (Auth.)

  7. Low voltage 80 KV to 125 KV electron processors

    International Nuclear Information System (INIS)

    Lauppi, U.V.

    1999-01-01

    The classic electron beam technology made use of accelerating energies in the voltage range of 300 to 800 kV. The first EB processors - built for the curing of coatings - operated at 300 kV. The products to be treated were thicker than a simple layer of coating with thicknesses up to 100g and more. It was only in the beginning of the 1970's that industrial EB processors with accelerating voltages below 300 kV appeared on the market. Our company developed the first commercial electron accelerator without a beam scanner. The new EB machine featured a linear cathode, emitting a shower or 'curtain' of electrons over the full width of the product. These units were much smaller than anv previous EB processors and dedicated to the curing of coatings and other thin layers. ESI's first EB units operated with accelerating voltages between 150 and 200 kV. In 1993 ESI announced the introduction of a new generation of Electrocure. EB processors operating at 120 kV, and in 1998, at the RadTech North America '98 Conference in Chicago, the introduction of an 80 kV electron beam processor under the designation Microbeam LV

  8. KV4.3 N-terminal deletion mutant Δ2–39

    Science.gov (United States)

    Hovind, Laura J; Skerritt, Matthew R

    2011-01-01

    Gating transitions in the KV4.3 N-terminal deletion mutant Δ2–39 were characterized in the absence and presence of KChIP2b. We particularly focused on gating characteristics of macroscopic (open state) versus closed state inactivation (CSI) and recovery. In the absence of KChIP2b Δ2–39 did not significantly alter the steady-state activation “a4” relationship or general CSI characteristics, but it did slow the kinetics of deactivation, macroscopic inactivation and macroscopic recovery. Recovery kinetics (for both WT KV4.3 and Δ2–39) were complicated and displayed sigmoidicity, a process which was enhanced by Δ2–39. Deletion of the proximal N-terminal domain therefore appeared to specifically slow mechanisms involved in regulating gating transitions occurring after the channel open state(s) had been reached. In the presence of KChIP2b Δ2–39 recovery kinetics (from both macroscopic and CSI) were accelerated, with an apparent reduction in initial sigmoidicity. Hyperpolarizing shifts in both “a4” and isochronal inactivation “i” were also produced. KChIP2b-mediated remodeling of KV4.3 gating transitions was therefore not obligatorily dependent upon an intact N-terminus. To account for these effects we propose that KChIP2 regulatory domains exist in KV4.3 α subunit regions outside of the proximal N-terminal. In addition to regulating macroscopic inactivation, we also propose that the KV4.3 N-terminus may act as a novel regulator of deactivation-recovery coupling. PMID:21057209

  9. Nuclear physics: Macroscopic aspects

    International Nuclear Information System (INIS)

    Swiatecki, W.J.

    1993-12-01

    A systematic macroscopic, leptodermous approach to nuclear statics and dynamics is described, based formally on the assumptions ℎ → 0 and b/R << 1, where b is the surface diffuseness and R the nuclear radius. The resulting static model of shell-corrected nuclear binding energies and deformabilities is accurate to better than 1 part in a thousand and yields a firm determination of the principal properties of the nuclear fluid. As regards dynamics, the above approach suggests that nuclear shape evolutions will often be dominated by dissipation, but quantitative comparisons with experimental data are more difficult than in the case of statics. In its simplest liquid drop version the model exhibits interesting formal connections to the classic astronomical problem of rotating gravitating masses

  10. Mechanosensitive gating of Kv channels.

    Directory of Open Access Journals (Sweden)

    Catherine E Morris

    Full Text Available K-selective voltage-gated channels (Kv are multi-conformation bilayer-embedded proteins whose mechanosensitive (MS Popen(V implies that at least one conformational transition requires the restructuring of the channel-bilayer interface. Unlike Morris and colleagues, who attributed MS-Kv responses to a cooperative V-dependent closed-closed expansion↔compaction transition near the open state, Mackinnon and colleagues invoke expansion during a V-independent closed↔open transition. With increasing membrane tension, they suggest, the closed↔open equilibrium constant, L, can increase >100-fold, thereby taking steady-state Popen from 0→1; "exquisite sensitivity to small…mechanical perturbations", they state, makes a Kv "as much a mechanosensitive…as…a voltage-dependent channel". Devised to explain successive gK(V curves in excised patches where tension spontaneously increased until lysis, their L-based model falters in part because of an overlooked IK feature; with recovery from slow inactivation factored in, their g(V datasets are fully explained by the earlier model (a MS V-dependent closed-closed transition, invariant L≥4. An L-based MS-Kv predicts neither known Kv time courses nor the distinctive MS responses of Kv-ILT. It predicts Kv densities (hence gating charge per V-sensor several-fold different from established values. If opening depended on elevated tension (L-based model, standard gK(V operation would be compromised by animal cells' membrane flaccidity. A MS V-dependent transition is, by contrast, unproblematic on all counts. Since these issues bear directly on recent findings that mechanically-modulated Kv channels subtly tune pain-related excitability in peripheral mechanoreceptor neurons we undertook excitability modeling (evoked action potentials. Kvs with MS V-dependent closed-closed transitions produce nuanced mechanically-modulated excitability whereas an L-based MS-Kv yields extreme, possibly excessive

  11. Microscopic and macroscopic bell inequalities

    International Nuclear Information System (INIS)

    Santos, E.

    1984-01-01

    The Bell inequalities, being derived for micro-systems, cannot be tested by (macroscopic) experiments without additional assumptions. A macroscopic definition of local realism is proposed which might be the starting point for deriving Bell inequalities testable without auxiliary assumptions. (orig.)

  12. Modeling-independent elucidation of inactivation pathways in recombinant and native A-type Kv channels

    Science.gov (United States)

    Fineberg, Jeffrey D.; Ritter, David M.

    2012-01-01

    A-type voltage-gated K+ (Kv) channels self-regulate their activity by inactivating directly from the open state (open-state inactivation [OSI]) or by inactivating before they open (closed-state inactivation [CSI]). To determine the inactivation pathways, it is often necessary to apply several pulse protocols, pore blockers, single-channel recording, and kinetic modeling. However, intrinsic hurdles may preclude the standardized application of these methods. Here, we implemented a simple method inspired by earlier studies of Na+ channels to analyze macroscopic inactivation and conclusively deduce the pathways of inactivation of recombinant and native A-type Kv channels. We investigated two distinct A-type Kv channels expressed heterologously (Kv3.4 and Kv4.2 with accessory subunits) and their native counterparts in dorsal root ganglion and cerebellar granule neurons. This approach applies two conventional pulse protocols to examine inactivation induced by (a) a simple step (single-pulse inactivation) and (b) a conditioning step (double-pulse inactivation). Consistent with OSI, the rate of Kv3.4 inactivation (i.e., the negative first derivative of double-pulse inactivation) precisely superimposes on the profile of the Kv3.4 current evoked by a single pulse because the channels must open to inactivate. In contrast, the rate of Kv4.2 inactivation is asynchronous, already changing at earlier times relative to the profile of the Kv4.2 current evoked by a single pulse. Thus, Kv4.2 inactivation occurs uncoupled from channel opening, indicating CSI. Furthermore, the inactivation time constant versus voltage relation of Kv3.4 decreases monotonically with depolarization and levels off, whereas that of Kv4.2 exhibits a J-shape profile. We also manipulated the inactivation phenotype by changing the subunit composition and show how CSI and CSI combined with OSI might affect spiking properties in a full computational model of the hippocampal CA1 neuron. This work unambiguously

  13. Quantum equilibria for macroscopic systems

    International Nuclear Information System (INIS)

    Grib, A; Khrennikov, A; Parfionov, G; Starkov, K

    2006-01-01

    Nash equilibria are found for some quantum games with particles with spin-1/2 for which two spin projections on different directions in space are measured. Examples of macroscopic games with the same equilibria are given. Mixed strategies for participants of these games are calculated using probability amplitudes according to the rules of quantum mechanics in spite of the macroscopic nature of the game and absence of Planck's constant. A possible role of quantum logical lattices for the existence of macroscopic quantum equilibria is discussed. Some examples for spin-1 cases are also considered

  14. Quantum equilibria for macroscopic systems

    Energy Technology Data Exchange (ETDEWEB)

    Grib, A [Department of Theoretical Physics and Astronomy, Russian State Pedagogical University, St. Petersburg (Russian Federation); Khrennikov, A [Centre for Mathematical Modelling in Physics and Cognitive Sciences Vaexjoe University (Sweden); Parfionov, G [Department of Mathematics, St. Petersburg State University of Economics and Finances (Russian Federation); Starkov, K [Department of Mathematics, St. Petersburg State University of Economics and Finances (Russian Federation)

    2006-06-30

    Nash equilibria are found for some quantum games with particles with spin-1/2 for which two spin projections on different directions in space are measured. Examples of macroscopic games with the same equilibria are given. Mixed strategies for participants of these games are calculated using probability amplitudes according to the rules of quantum mechanics in spite of the macroscopic nature of the game and absence of Planck's constant. A possible role of quantum logical lattices for the existence of macroscopic quantum equilibria is discussed. Some examples for spin-1 cases are also considered.

  15. Superconductivity and macroscopic quantum phenomena

    International Nuclear Information System (INIS)

    Rogovin, D.; Scully, M.

    1976-01-01

    It is often asserted that superconducting systems are manifestations of quantum mechanics on a macroscopic scale. In this review article it is demonstrated that this quantum assertion is true within the framework of the microscopic theory of superconductivity. (Auth.)

  16. Macroscopic constraints on string unification

    International Nuclear Information System (INIS)

    Taylor, T.R.

    1989-03-01

    The comparison of sting theory with experiment requires a huge extrapolation from the microscopic distances, of order of the Planck length, up to the macroscopic laboratory distances. The quantum effects give rise to large corrections to the macroscopic predictions of sting unification. I discus the model-independent constraints on the gravitational sector of string theory due to the inevitable existence of universal Fradkin-Tseytlin dilatons. 9 refs

  17. Interpretation of macroscopic quantum phenomena

    International Nuclear Information System (INIS)

    Baumann, K.

    1986-01-01

    It is argued that a quantum theory without observer is required for the interpretation of macroscopic quantum tunnelling. Such a theory is obtained by augmenting QED by the actual electric field in the rest system of the universe. An equation of the motion of this field is formulated form which the correct macroscopic behavior of the universe and the validity of the Born interpretation is derived. Care is taken to use mathematically sound concepts only. (Author)

  18. Hvor fosser kvælstoffet hen?

    DEFF Research Database (Denmark)

    Larsen, Torben

    Der har i Ingeniøren inden i et par måneder kunne læses adskillelige ivrige indlæg om de danske fjordes evne til at fjerne kvælstof. Kvælstof fosser ud af fjordene? lød en af de første overskrifter. Få uger efter blev det stik modsatte synspunkt fremført under overskriften Fjordene holder på kvæl...

  19. Macroscopic models for traffic safety.

    NARCIS (Netherlands)

    Oppe, S.

    1988-01-01

    Recently there has been an increased interest in the application of macroscopic models for the description of developments in traffic safety. A discussion was started on the causes of the sudden decrease in the number of fatal and injury accidents after 1974. Before that time these numbers had

  20. The electrically silent Kv6.4 subunit confers hyperpolarized gating charge movement in Kv2.1/Kv6.4 heterotetrameric channels.

    Directory of Open Access Journals (Sweden)

    Elke Bocksteins

    Full Text Available The voltage-gated K(+ (Kv channel subunit Kv6.4 does not form functional homotetrameric channels but co-assembles with Kv2.1 to form functional Kv2.1/Kv6.4 heterotetrameric channels. Compared to Kv2.1 homotetramers, Kv6.4 exerts a ~40 mV hyperpolarizing shift in the voltage-dependence of Kv2.1/Kv6.4 channel inactivation, without a significant effect on activation gating. However, the underlying mechanism of this Kv6.4-induced modulation of Kv2.1 channel inactivation, and whether the Kv6.4 subunit participates in the voltage-dependent gating of heterotetrameric channels is not well understood. Here we report distinct gating charge movement of Kv2.1/Kv6.4 heterotetrameric channels, compared to Kv2.1 homotetramers, as revealed by gating current recordings from mammalian cells expressing these channels. The gating charge movement of Kv2.1/Kv6.4 heterotetrameric channels displayed an extra component around the physiological K(+ equilibrium potential, characterized by a second sigmoidal relationship of the voltage-dependence of gating charge movement. This distinct gating charge displacement reflects movement of the Kv6.4 voltage-sensing domain and has a voltage-dependency that matches the hyperpolarizing shift in Kv2.1/Kv6.4 channel inactivation. These results provide a mechanistic basis for the modulation of Kv2.1 channel inactivation gating kinetics by silent Kv6.4 subunits.

  1. French 400 kV network

    Energy Technology Data Exchange (ETDEWEB)

    Pelissier, R

    1965-11-01

    A 400 kV transmission network has been constructed to carry hydroelectric power from the Alps and the Massif Central to Paris at peak hours and to carry power in the reverse direction in off-peak hours. A double circuit-ring at 400 kV encircling the Paris region is also nearing completion. Measures have to be taken to counter the very high short-circuit currents in such a network. A 730 kV network will eventually become necessary. The consequent multiplicity of transmission voltages will give rise to further problems. Collaboration with neighboring countries is envisaged. The problems of stability and synchronization posed by the new system are described and solutions suggested. The new circuit-breaking requirements are discussed, and details of tower design for 400 kV and 730 kV are given.

  2. Decreased expression of Kv7 channels in Hirchsprung's disease.

    Science.gov (United States)

    O'Donnell, Anne-Marie; Coyle, David; Puri, Prem

    2017-07-01

    Voltage-dependent K + channels (Kv channels) participate in electrical rhythmicity and smooth muscle responses and are regulated by excitatory and inhibitory neurotransmitters. Kv channels also participate in the interstitial cell of Cajal (ICC) and smooth muscle cell (SMC) responses to neural inputs. The Kv family consists of 12 subfamilies, Kv1-Kv12, with five members of the Kv7 family identified to date: Kv7.1-Kv7.5. A recent study identified the potassium channel Kv7.5 as having a role in the excitability of ICC-IM in the mouse colon. We therefore designed this study to test the hypothesis that Kv7 channels are present in the normal human colon and are reduced in Hirschprung's disease (HSCR). HSCR tissue specimens were collected at the time of pull-through surgery (n=10), while normal control tissue specimens were obtained at the time of colostomy closure in patients with imperforate anus (n=10). Kv7.3-Kv7.5 immunohistochemistry was performed and visualized using confocal microscopy to assess their distribution. Western blot analysis was undertaken to determine Kv7.3-Kv7.5 protein quantification. Kv7.3 and Kv7.4-immunoreactivity was co-localized with neuron and ICC markers, while Kv7.5 was found to be expressed on both ICCs and SMCs. Western blot analysis revealed similar levels of Kv7.3 and Kv7.5 expression in the normal colon and HSCR colon, while Kv7.4 proteins were found to be markedly decreased in ganglionic specimens and decreased further in aganglionic specimens. A deficiency of Kv7.4 channels in the ganglionic and aganglionic bowel may place a role in colonic dysmotility in HSCR. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Seismic scanning tunneling macroscope - Theory

    KAUST Repository

    Schuster, Gerard T.

    2012-09-01

    We propose a seismic scanning tunneling macroscope (SSTM) that can detect the presence of sub-wavelength scatterers in the near-field of either the source or the receivers. Analytic formulas for the time reverse mirror (TRM) profile associated with a single scatterer model show that the spatial resolution limit to be, unlike the Abbe limit of λ/2, independent of wavelength and linearly proportional to the source-scatterer separation as long as the point scatterer is in the near-field region; if the sub-wavelength scatterer is a spherical impedance discontinuity then the resolution will also be limited by the radius of the sphere. Therefore, superresolution imaging can be achieved as the scatterer approaches the source. This is analogous to an optical scanning tunneling microscope that has sub-wavelength resolution. Scaled to seismic frequencies, it is theoretically possible to extract 100 Hz information from 20 Hz data by imaging of near-field seismic energy.

  4. Seismic scanning tunneling macroscope - Theory

    KAUST Repository

    Schuster, Gerard T.; Hanafy, Sherif M.; Huang, Yunsong

    2012-01-01

    We propose a seismic scanning tunneling macroscope (SSTM) that can detect the presence of sub-wavelength scatterers in the near-field of either the source or the receivers. Analytic formulas for the time reverse mirror (TRM) profile associated with a single scatterer model show that the spatial resolution limit to be, unlike the Abbe limit of λ/2, independent of wavelength and linearly proportional to the source-scatterer separation as long as the point scatterer is in the near-field region; if the sub-wavelength scatterer is a spherical impedance discontinuity then the resolution will also be limited by the radius of the sphere. Therefore, superresolution imaging can be achieved as the scatterer approaches the source. This is analogous to an optical scanning tunneling microscope that has sub-wavelength resolution. Scaled to seismic frequencies, it is theoretically possible to extract 100 Hz information from 20 Hz data by imaging of near-field seismic energy.

  5. Functional analysis of Kv1.2 and paddle chimera Kv channels in planar lipid bilayers

    Science.gov (United States)

    Tao, Xiao; MacKinnon, Roderick

    2010-01-01

    Summary Voltage-dependent K+ channels play key roles in shaping electrical signaling in both excitable as well as non-excitable cells. These channels open and close in response to the voltage changes across the cell membrane. Many studies have been carried out in order to understand the voltage sensing mechanism. Our laboratory recently determined the atomic structures of a mammalian voltage-dependent K+ channel Kv1.2 and a mutant of Kv1.2 named the ‘paddle-chimera’ channel, in which the voltage sensor paddle was transferred from Kv2.1 to Kv1.2. These two structures provide atomic descriptions of voltage-dependent channels with unprecedented clarity. Until now the functional integrity of these two channels biosynthesized in yeast cells have not been assessed. Here we report the electrophysiological and pharmacological properties of Kv1.2 and the paddle chimera channels in planar lipid bilayers. We demonstrate that Pichia yeast produce ‘normally functioning’ mammalian voltage-dependent K+ channels with qualitatively similar features to the Shaker K+ channel in the absence of the N-terminal inactivation gate, and that the paddle chimera mutant channel functions as well as Kv1.2. We find, however, that in several respects the Kv1.2 channel exhibits functional properties that are distinct from Kv1.2 channels reported in the literature. PMID:18638484

  6. Rank distributions: A panoramic macroscopic outlook

    Science.gov (United States)

    Eliazar, Iddo I.; Cohen, Morrel H.

    2014-01-01

    This paper presents a panoramic macroscopic outlook of rank distributions. We establish a general framework for the analysis of rank distributions, which classifies them into five macroscopic "socioeconomic" states: monarchy, oligarchy-feudalism, criticality, socialism-capitalism, and communism. Oligarchy-feudalism is shown to be characterized by discrete macroscopic rank distributions, and socialism-capitalism is shown to be characterized by continuous macroscopic size distributions. Criticality is a transition state between oligarchy-feudalism and socialism-capitalism, which can manifest allometric scaling with multifractal spectra. Monarchy and communism are extreme forms of oligarchy-feudalism and socialism-capitalism, respectively, in which the intrinsic randomness vanishes. The general framework is applied to three different models of rank distributions—top-down, bottom-up, and global—and unveils each model's macroscopic universality and versatility. The global model yields a macroscopic classification of the generalized Zipf law, an omnipresent form of rank distributions observed across the sciences. An amalgamation of the three models establishes a universal rank-distribution explanation for the macroscopic emergence of a prevalent class of continuous size distributions, ones governed by unimodal densities with both Pareto and inverse-Pareto power-law tails.

  7. 250 kV aim for hvdc valves

    Energy Technology Data Exchange (ETDEWEB)

    1966-06-01

    Development now being carried out by ASEA is aimed at increasing the normal operating voltage for a mercury arc valve to 250 kV dc. The maximum direct voltage per valve group, with one valve in each arm of the bridge, is 125 kV for equipment already in operation in New Zealand, Japan, and Konti Scan. Valves for 130 kV and 133 kV operation are under construction for the Vancouver and the Pacific Intertie 1 links.

  8. Functional properties of human neuronal Kv11 channels

    DEFF Research Database (Denmark)

    Einarsen, Karoline; Calloe, Kirstine; Grunnet, Morten

    2009-01-01

    Kv11 potassium channels are important for regulation of the membrane potential. Kv11.2 and Kv11.3 are primarily found in the nervous system, where they most likely are involved in the regulation of neuronal excitability. Two isoforms of human Kv11.2 have been published so far. Here, we present...... current characteristics of the isoforms presented in this work may contribute to the regulation of neuronal excitability....

  9. The anticonvulsant retigabine suppresses neuronal Kv2-mediated currents

    DEFF Research Database (Denmark)

    Stas, Jeroen I; Bocksteins, Elke; Jensen, Camilla S

    2016-01-01

    Enhancement of neuronal M-currents, generated through KV7.2-KV7.5 channels, has gained much interest for its potential in developing treatments for hyperexcitability-related disorders such as epilepsy. Retigabine, a KV7 channel opener, has proven to be an effective anticonvulsant and has recently...

  10. Macroscopic transport by synthetic molecular machines

    NARCIS (Netherlands)

    Berna, J; Leigh, DA; Lubomska, M; Mendoza, SM; Perez, EM; Rudolf, P; Teobaldi, G; Zerbetto, F

    Nature uses molecular motors and machines in virtually every significant biological process, but demonstrating that simpler artificial structures operating through the same gross mechanisms can be interfaced with - and perform physical tasks in - the macroscopic world represents a significant hurdle

  11. Macroscopic quantum waves in non local theories

    International Nuclear Information System (INIS)

    Ventura, I.

    1979-01-01

    By means of an expansion in the density, it is shown that Macroscopic Quantum Waves also apear in non local theories. This result reinforces the conjecture that these waves should exist in liquid 4 He. (Author) [pt

  12. Macroscopic quantum waves in non local theories

    International Nuclear Information System (INIS)

    Ventura, I.

    1979-01-01

    By means of an expansion in the density, it is shown that Macroscopic Quantum Waves also appear in non local theories. This result reinforces the conjecture that these waves should exist in liquid 4 He [pt

  13. Assessments of macroscopicity for quantum optical states

    DEFF Research Database (Denmark)

    Laghaout, Amine; Neergaard-Nielsen, Jonas Schou; Andersen, Ulrik Lund

    2015-01-01

    With the slow but constant progress in the coherent control of quantum systems, it is now possible to create large quantum superpositions. There has therefore been an increased interest in quantifying any claims of macroscopicity. We attempt here to motivate three criteria which we believe should...... enter in the assessment of macroscopic quantumness: The number of quantum fluctuation photons, the purity of the states, and the ease with which the branches making up the state can be distinguished. © 2014....

  14. Nuclear fission as a macroscopic quantum tunneling

    International Nuclear Information System (INIS)

    Takigawa, N.

    1995-01-01

    We discuss nuclear fission from the point of view of a macroscopic quantum tunneling, one of whose major interests is to study the effects of environments on the tunneling rate of a macroscopic variable. We show that a vibrational excitation of the fissioning nucleus significantly enhances the fission rate. We show this effect by two different methods. The one is to treat the vibrational excitation as an environmental degree of freedom, the other treats the fission as a two dimensional quantum tunneling. (author)

  15. Adrenergic Stress Protection of Human iPS Cell-Derived Cardiomyocytes by Fast Kv7.1 Recycling

    Directory of Open Access Journals (Sweden)

    Ilaria Piccini

    2017-09-01

    Full Text Available The fight-or-flight response (FFR, a physiological acute stress reaction, involves positive chronotropic and inotropic effects on heart muscle cells mediated through β-adrenoceptor activation. Increased systolic calcium is required to enable stronger heart contractions whereas elevated potassium currents are to limit the duration of the action potentials and prevent arrhythmia. The latter effect is accomplished by an increased functional activity of the Kv7.1 channel encoded by KCNQ1. Current knowledge, however, does not sufficiently explain the full extent of rapid Kv7.1 activation and may hence be incomplete. Using inducible genetic KCNQ1 complementation in KCNQ1-deficient human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs, we here reinvestigate the functional role of Kv7.1 in adapting human CMs to adrenergic stress. Under baseline conditions, Kv7.1 was barely detectable at the plasma membrane of hiPSC-CMs, yet it fully protected these from adrenergic stress-induced beat-to-beat variability of repolarization and torsade des pointes-like arrhythmia. Furthermore, isoprenaline treatment increased field potential durations specifically in KCNQ1-deficient CMs to cause these adverse macroscopic effects. Mechanistically, we find that the protective action by Kv7.1 resides in a rapid translocation of channel proteins from intracellular stores to the plasma membrane, induced by adrenergic signaling. Gene silencing experiments targeting RAB GTPases, mediators of intracellular vesicle trafficking, showed that fast Kv7.1 recycling under acute stress conditions is RAB4A-dependent.Our data reveal a key mechanism underlying the rapid adaptation of human cardiomyocytes to adrenergic stress. These findings moreover aid to the understanding of disease pathology in long QT syndrome and bear important implications for safety pharmacological screening.

  16. The subfamily-specific interaction between Kv2.1 and Kv6.4 subunits is determined by interactions between the N- and C-termini.

    Directory of Open Access Journals (Sweden)

    Elke Bocksteins

    Full Text Available The "silent" voltage-gated potassium (KvS channel subunit Kv6.4 does not form electrically functional homotetramers at the plasma membrane but assembles with Kv2.1 subunits, generating functional Kv2.1/Kv6.4 heterotetramers. The N-terminal T1 domain determines the subfamily-specific assembly of Kv1-4 subunits by preventing interactions between subunits that belong to different subfamilies. For Kv6.4, yeast-two-hybrid experiments showed an interaction of the Kv6.4 N-terminus with the Kv2.1 N-terminus, but unexpectedly also with the Kv3.1 N-terminus. We confirmed this interaction by Fluorescence Resonance Energy Transfer (FRET and co-immunoprecipitation (co-IP using N-terminal Kv3.1 and Kv6.4 fragments. However, full-length Kv3.1 and Kv6.4 subunits do not form heterotetramers at the plasma membrane. Therefore, additional interactions between the Kv6.4 and Kv2.1 subunits should be important in the Kv2.1/Kv6.4 subfamily-specificity. Using FRET and co-IP approaches with N- and C-terminal fragments we observed that the Kv6.4 C-terminus physically interacts with the Kv2.1 N-terminus but not with the Kv3.1 N-terminus. The N-terminal amino acid sequence CDD which is conserved between Kv2 and KvS subunits appeared to be a key determinant since charge reversals with arginine substitutions abolished the interaction between the N-terminus of Kv2.1 and the C-terminus of both Kv2.1 and Kv6.4. In addition, the Kv6.4(CKv3.1 chimera in which the C-terminus of Kv6.4 was replaced by the corresponding domain of Kv3.1, disrupted the assembly with Kv2.1. These results indicate that the subfamily-specific Kv2.1/Kv6.4 heterotetramerization is determined by interactions between Kv2.1 and Kv6.4 that involve both the N- and C-termini in which the conserved N-terminal CDD sequence plays a key role.

  17. Effects of haloperidol on Kv4.3 potassium channels.

    Science.gov (United States)

    Lee, Hong Joon; Sung, Ki-Wug; Hahn, Sang June

    2014-10-05

    Haloperidol is commonly used in clinical practice to treat acute and chronic psychosis, but it also has been associated with adverse cardiovascular events. We investigated the effects of haloperidol on Kv4.3 currents stably expressed in CHO cells using a whole-cell patch-clamp technique. Haloperidol did not significantly inhibit the peak amplitude of Kv4.3, but accelerated the decay rate of inactivation of Kv4.3 in a concentration-dependent manner. Thus, the effects of haloperidol on Kv4.3 were estimated from the integral of the Kv4.3 currents during the depolarization pulse. The Kv4.3 was decreased by haloperidol in a concentration-dependent manner with an IC50 value of 3.6 μM. Haloperidol accelerated the decay rate of Kv4.3 inactivation and activation kinetics in a concentration-dependent manner, thereby decreasing the time-to-peak. Haloperidol shifted the voltage dependence of the steady-state activation and inactivation of Kv4.3 in a hyperpolarizing direction. Haloperidol also caused an acceleration of the closed-state inactivation of Kv4.3. Haloperidol produced a use-dependent block of Kv4.3, which was accompanied by a slowing of recovery from the inactivation of Kv4.3. These results suggest that haloperidol blocks Kv4.3 by both interacting with the open state of Kv4.3 channels during depolarization and accelerating the closed-state inactivation at subthreshold membrane potentials. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Macroscopic averages in Qed in material media

    International Nuclear Information System (INIS)

    Dutra, S.M.; Furuya, K.

    1997-01-01

    The starting point of macroscopic theories of quantum electrodynamics in material media is usually the classical macroscopic Maxwell equations that are then quantized. Such approach however, is based on the assumption that a macroscopic description is attainable, i.e., it assumes that we can describe the effect of the atoms of material on the field only in terms of a dielectric constant in the regime where the field has to be treated quantum mechanically. The problem we address is whether this assumption is valid at all and if so, under what conditions. We have chosen a simple model, which allows us to start from first principles and determine the validity of these approximations, without simply taking them for granted as in previous papers

  19. Conversion of light into macroscopic helical motion

    Science.gov (United States)

    Iamsaard, Supitchaya; Aßhoff, Sarah J.; Matt, Benjamin; Kudernac, Tibor; Cornelissen, Jeroen J. L. M.; Fletcher, Stephen P.; Katsonis, Nathalie

    2014-03-01

    A key goal of nanotechnology is the development of artificial machines capable of converting molecular movement into macroscopic work. Although conversion of light into shape changes has been reported and compared to artificial muscles, real applications require work against an external load. Here, we describe the design, synthesis and operation of spring-like materials capable of converting light energy into mechanical work at the macroscopic scale. These versatile materials consist of molecular switches embedded in liquid-crystalline polymer springs. In these springs, molecular movement is converted and amplified into controlled and reversible twisting motions. The springs display complex motion, which includes winding, unwinding and helix inversion, as dictated by their initial shape. Importantly, they can produce work by moving a macroscopic object and mimicking mechanical movements, such as those used by plant tendrils to help the plant access sunlight. These functional materials have potential applications in micromechanical systems, soft robotics and artificial muscles.

  20. Nonequilibrium work relation in a macroscopic system

    International Nuclear Information System (INIS)

    Sughiyama, Yuki; Ohzeki, Masayuki

    2013-01-01

    We reconsider a well-known relationship between the fluctuation theorem and the second law of thermodynamics by evaluating stochastic evolution of the density field (probability measure valued process). In order to establish a bridge between microscopic and macroscopic behaviors, we must take the thermodynamic limit of a stochastic dynamical system following the standard procedure in statistical mechanics. The thermodynamic path characterizing a dynamical behavior in the macroscopic scale can be formulated as an infimum of the action functional for the stochastic evolution of the density field. In our formulation, the second law of thermodynamics can be derived only by symmetry of the action functional without recourse to the Jarzynski equality. Our formulation leads to a nontrivial nonequilibrium work relation for metastable (quasi-stationary) states, which are peculiar in the macroscopic system. We propose a prescription for computing the free energy for metastable states based on the resultant work relation. (paper)

  1. A Review on Macroscopic Pedestrian Flow Modelling

    Directory of Open Access Journals (Sweden)

    Anna Kormanová

    2013-12-01

    Full Text Available This paper reviews several various approaches to macroscopic pedestrian modelling. It describes hydrodynamic models based on similarity of pedestrian flow with fluids and gases; first-order flow models that use fundamental diagrams and conservation equation; and a model similar to LWR vehicular traffic model, which allows non-classical shocks. At the end of the paper there is stated a comparison of described models, intended to find appropriate macroscopic model to eventually be a part of a hybrid model. The future work of the author is outlined.

  2. Macroscopic effects in attosecond pulse generation

    International Nuclear Information System (INIS)

    Ruchon, T; Varju, K; Mansten, E; Swoboda, M; L'Huillier, A; Hauri, C P; Lopez-Martens, R

    2008-01-01

    We examine how the generation and propagation of high-order harmonics in a partly ionized gas medium affect their strength and synchronization. The temporal properties of the resulting attosecond pulses generated in long gas targets can be significantly influenced by macroscopic effects, in particular by the intensity in the medium and the degree of ionization which control the dispersion. Under some conditions, the use of gas targets longer than the absorption length can lead to the generation of compressed attosecond pulses. We show these macroscopic effects experimentally, using a 6 mm-long argon-filled gas cell as the generating medium

  3. Macroscopic effects in attosecond pulse generation

    Energy Technology Data Exchange (ETDEWEB)

    Ruchon, T; Varju, K; Mansten, E; Swoboda, M; L' Huillier, A [Department of Physics, Lund University, PO Box 118, SE-221 00 Lund (Sweden); Hauri, C P; Lopez-Martens, R [Laboratoire d' Optique Appliquee, Ecole Nationale Superieure des Techniques Avancees (ENSTA)-Ecole Polytechnique CNRS UMR 7639, 91761 Palaiseau (France)], E-mail: anne.lhuillier@fysik.lth.se

    2008-02-15

    We examine how the generation and propagation of high-order harmonics in a partly ionized gas medium affect their strength and synchronization. The temporal properties of the resulting attosecond pulses generated in long gas targets can be significantly influenced by macroscopic effects, in particular by the intensity in the medium and the degree of ionization which control the dispersion. Under some conditions, the use of gas targets longer than the absorption length can lead to the generation of compressed attosecond pulses. We show these macroscopic effects experimentally, using a 6 mm-long argon-filled gas cell as the generating medium.

  4. Kv7 channels can function without constitutive calmodulin tethering.

    Directory of Open Access Journals (Sweden)

    Juan Camilo Gómez-Posada

    Full Text Available M-channels are voltage-gated potassium channels composed of Kv7.2-7.5 subunits that serve as important regulators of neuronal excitability. Calmodulin binding is required for Kv7 channel function and mutations in Kv7.2 that disrupt calmodulin binding cause Benign Familial Neonatal Convulsions (BFNC, a dominantly inherited human epilepsy. On the basis that Kv7.2 mutants deficient in calmodulin binding are not functional, calmodulin has been defined as an auxiliary subunit of Kv7 channels. However, we have identified a presumably phosphomimetic mutation S511D that permits calmodulin-independent function. Thus, our data reveal that constitutive tethering of calmodulin is not required for Kv7 channel function.

  5. Macroscopic optical response and photonic bands

    International Nuclear Information System (INIS)

    Pérez-Huerta, J S; Luis Mochán, W; Ortiz, Guillermo P; Mendoza, Bernardo S

    2013-01-01

    We develop a formalism for the calculation of the macroscopic dielectric response of composite systems made of particles of one material embedded periodically within a matrix of another material, each of which is characterized by a well-defined dielectric function. The nature of these dielectric functions is arbitrary, and could correspond to dielectric or conducting, transparent or opaque, absorptive and dispersive materials. The geometry of the particles and the Bravais lattice of the composite are also arbitrary. Our formalism goes beyond the long-wavelength approximation as it fully incorporates retardation effects. We test our formalism through the study of the propagation of electromagnetic waves in two-dimensional photonic crystals made of periodic arrays of cylindrical holes in a dispersionless dielectric host. Our macroscopic theory yields a spatially dispersive macroscopic response which allows the calculation of the full photonic band structure of the system, as well as the characterization of its normal modes, upon substitution into the macroscopic field equations. We can also account approximately for the spatial dispersion through a local magnetic permeability and analyze the resulting dispersion relation, obtaining a region of left handedness. (paper)

  6. Berkeley Experiments on Superfluid Macroscopic Quantum Effects

    International Nuclear Information System (INIS)

    Packard, Richard

    2006-01-01

    This paper provides a brief history of the evolution of the Berkeley experiments on macroscopic quantum effects in superfluid helium. The narrative follows the evolution of the experiments proceeding from the detection of single vortex lines to vortex photography to quantized circulation in 3He to Josephson effects and superfluid gyroscopes in both 4He and 3He

  7. Macroscopic sizes of field of superrelativistic charges

    International Nuclear Information System (INIS)

    Strel'tsov, V.N.

    1995-01-01

    Based on the equation of Lienard-Wiechert equipotentials, it is shown that the field of superrelativistic charges reaches macroscopic sizes (e.g., R || = 2 m at E e = 50 GeV). This phenomenon serves an initial cause of the known considerable growth of formation length at high energies. 3 refs., 1 tab

  8. On quantum mechanics for macroscopic systems

    International Nuclear Information System (INIS)

    Primas, H.

    1992-01-01

    The parable of Schroedinger's cat may lead to several up-to date questions: how to treat open systems in quantum theory, how to treat thermodynamically irreversible processes in the quantum mechanics framework, how to explain, following the quantum theory, the existence, phenomenologically evident, of classical observables, what implies the predicted existence by the quantum theory of non localized macroscopic material object ?

  9. Molecular and functional characterization of Kv7 K+ channel in murine gastrointestinal smooth muscles

    DEFF Research Database (Denmark)

    Jepps, Thomas Andrew; Greenwood, Iain A; Moffatt, James D

    2009-01-01

    that K(v)7.x especially K(v)7.4 and K(v)7.5 are expressed in different regions of the murine gastrointestinal tract and blockers of K(v)7 channels augment inherent contractile activity. Drugs that selectively block K(v)7.4/7.5 might be promising therapeutics for the treatment of motility disorders...

  10. Analysis of the 35 KV substation secondary system

    Science.gov (United States)

    Zhao, Yong; Jiang, Jianguo; Jiang, Chunlei; Ren, Shuang; Liu, Songbin

    2017-04-01

    This paper analyzes the status of the two system of some 35KV users' substation in Daqing oil field, the deficiencies of the two system of the existing 35KV substation are found out. And put forward the opinion of acceptance in the future work. I hope it can able to work in the future on the protection of professional help.

  11. Macroscopic and non-linear quantum games

    International Nuclear Information System (INIS)

    Aerts, D.; D'Hooghe, A.; Posiewnik, A.; Pykacz, J.

    2005-01-01

    Full text: We consider two models of quantum games. The first one is Marinatto and Weber's 'restricted' quantum game in which only the identity and the spin-flip operators are used. We show that this quantum game allows macroscopic mechanistic realization with the use of a version of the 'macroscopic quantum machine' described by Aerts already in 1980s. In the second model we use non-linear quantum state transformations which operate on points of spin-1/2 on the Bloch sphere and which can be used to distinguish optimally between two non-orthogonal states. We show that efficiency of these non-linear strategies out-perform any linear ones. Some hints on the possible theory of non-linear quantum games are given. (author)

  12. Bimodality in macroscopic dynamics of nuclear fission

    International Nuclear Information System (INIS)

    Bastrukov, S.I.; Salamatin, V.S.; Strteltsova, O.I.; Molodtsova, I.V.; Podgainy, D.V.; )

    2000-01-01

    The elastodynamic collective model of nuclear fission is outlined whose underlying idea is that the stiff structure of nuclear shells imparts to nucleus properties typical of a small piece of an elastic solid. Emphasis is placed on the macroscopic dynamics of nuclear deformations resulting in fission by two energetically different modes. The low-energy S-mode is the fission due to disruption of elongated quadrupole spheroidal shape. The characteristic features of the high-energy T-mode of division by means of torsional shear deformations is the compact scission configuration. Analytic and numerical estimates for the macroscopic fission-barrier heights are presented, followed by discussion of fingerprints of the above dynamical bimodality in the available data [ru

  13. Macroscopic Quantum Resonators (MAQRO): 2015 update

    International Nuclear Information System (INIS)

    Kaltenbaek, Rainer; Aspelmeyer, Markus; Kiesel, Nikolai; Barker, Peter F.; Bose, Sougato; Bassi, Angelo; Bateman, James; Bongs, Kai; Cruise, Adrian Michael; Braxmaier, Claus; Brukner, Caslav; Christophe, Bruno; Rodrigues, Manuel; Chwalla, Michael; Johann, Ulrich; Cohadon, Pierre-Francois; Heidmann, Antoine; Lambrecht, Astrid; Reynaud, Serge; Curceanu, Catalina; Dholakia, Kishan; Mazilu, Michael; Diosi, Lajos; Doeringshoff, Klaus; Peters, Achim; Ertmer, Wolfgang; Rasel, Ernst M.; Gieseler, Jan; Novotny, Lukas; Rondin, Loic; Guerlebeck, Norman; Herrmann, Sven; Laemmerzahl, Claus; Hechenblaikner, Gerald; Hossenfelder, Sabine; Kim, Myungshik; Milburn, Gerard J.; Mueller, Holger; Paternostro, Mauro; Pikovski, Igor; Pilan Zanoni, Andre; Riedel, Charles Jess; Roura, Albert; Schleich, Wolfgang P.; Schmiedmayer, Joerg; Schuldt, Thilo; Schwab, Keith C.; Tajmar, Martin; Tino, Guglielmo M.; Ulbricht, Hendrik; Ursin, Rupert; Vedral, Vlatko

    2016-01-01

    Do the laws of quantum physics still hold for macroscopic objects - this is at the heart of Schroedinger's cat paradox - or do gravitation or yet unknown effects set a limit for massive particles? What is the fundamental relation between quantum physics and gravity? Ground-based experiments addressing these questions may soon face limitations due to limited free-fall times and the quality of vacuum and microgravity. The proposed mission Macroscopic Quantum Resonators (MAQRO) may overcome these limitations and allow addressing such fundamental questions. MAQRO harnesses recent developments in quantum optomechanics, high-mass matter-wave interferometry as well as state-of-the-art space technology to push macroscopic quantum experiments towards their ultimate performance limits and to open new horizons for applying quantum technology in space. The main scientific goal is to probe the vastly unexplored 'quantum-classical' transition for increasingly massive objects, testing the predictions of quantum theory for objects in a size and mass regime unachievable in ground-based experiments. The hardware will largely be based on available space technology. Here, we present the MAQRO proposal submitted in response to the 4th Cosmic Vision call for a medium-sized mission (M4) in 2014 of the European Space Agency (ESA) with a possible launch in 2025, and we review the progress with respect to the original MAQRO proposal for the 3rd Cosmic Vision call for a medium-sized mission (M3) in 2010. In particular, the updated proposal overcomes several critical issues of the original proposal by relying on established experimental techniques from high-mass matter-wave interferometry and by introducing novel ideas for particle loading and manipulation. Moreover, the mission design was improved to better fulfill the stringent environmental requirements for macroscopic quantum experiments. (orig.)

  14. Macroscopic Quantum Resonators (MAQRO): 2015 update

    Energy Technology Data Exchange (ETDEWEB)

    Kaltenbaek, Rainer [University of Vienna, Vienna Center for Quantum Science and Technology, Vienna (Austria); Aspelmeyer, Markus; Kiesel, Nikolai [University of Vienna, Vienna Center for Quantum Science and Technology, Vienna (Austria); Barker, Peter F.; Bose, Sougato [University College London, Department of Physics and Astronomy, London (United Kingdom); Bassi, Angelo [University of Trieste, Department of Physics, Trieste (Italy); INFN - Trieste Section, Trieste (Italy); Bateman, James [University of Swansea, Department of Physics, College of Science, Swansea (United Kingdom); Bongs, Kai; Cruise, Adrian Michael [University of Birmingham, School of Physics and Astronomy, Birmingham (United Kingdom); Braxmaier, Claus [University of Bremen, Center of Applied Space Technology and Micro Gravity (ZARM), Bremen (Germany); Institute of Space Systems, German Aerospace Center (DLR), Bremen (Germany); Brukner, Caslav [University of Vienna, Vienna Center for Quantum Science and Technology, Vienna (Austria); Austrian Academy of Sciences, Institute of Quantum Optics and Quantum Information (IQOQI), Vienna (Austria); Christophe, Bruno; Rodrigues, Manuel [The French Aerospace Lab, ONERA, Chatillon (France); Chwalla, Michael; Johann, Ulrich [Airbus Defence and Space GmbH, Immenstaad (Germany); Cohadon, Pierre-Francois; Heidmann, Antoine; Lambrecht, Astrid; Reynaud, Serge [ENS-PSL Research University, Laboratoire Kastler Brossel, UPMC-Sorbonne Universites, CNRS, College de France, Paris (France); Curceanu, Catalina [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Dholakia, Kishan; Mazilu, Michael [University of St. Andrews, School of Physics and Astronomy, St. Andrews (United Kingdom); Diosi, Lajos [Wigner Research Center for Physics, P.O. Box 49, Budapest (Hungary); Doeringshoff, Klaus; Peters, Achim [Humboldt-Universitaet zu Berlin, Institut fuer Physik, Berlin (Germany); Ertmer, Wolfgang; Rasel, Ernst M. [Leibniz Universitaet Hannover, Institut fuer Quantenoptik, Hannover (Germany); Gieseler, Jan; Novotny, Lukas; Rondin, Loic [ETH Zuerich, Photonics Laboratory, Zuerich (Switzerland); Guerlebeck, Norman; Herrmann, Sven; Laemmerzahl, Claus [University of Bremen, Center of Applied Space Technology and Micro Gravity (ZARM), Bremen (Germany); Hechenblaikner, Gerald [Airbus Defence and Space GmbH, Immenstaad (Germany); European Southern Observatory (ESO), Garching bei Muenchen (Germany); Hossenfelder, Sabine [KTH Royal Institute of Technology and Stockholm University, Nordita, Stockholm (Sweden); Kim, Myungshik [Imperial College London, QOLS, Blackett Laboratory, London (United Kingdom); Milburn, Gerard J. [University of Queensland, ARC Centre for Engineered Quantum Systems, Brisbane (Australia); Mueller, Holger [University of California, Department of Physics, Berkeley, CA (United States); Paternostro, Mauro [Queen' s University, Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Belfast (United Kingdom); Pikovski, Igor [Harvard-Smithsonian Center for Astrophysics, ITAMP, Cambridge, MA (United States); Pilan Zanoni, Andre [Airbus Defence and Space GmbH, Immenstaad (Germany); CERN - European Organization for Nuclear Research, EN-STI-TCD, Geneva (Switzerland); Riedel, Charles Jess [Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada); Roura, Albert [Universitaet Ulm, Institut fuer Quantenphysik, Ulm (Germany); Schleich, Wolfgang P. [Universitaet Ulm, Institut fuer Quantenphysik, Ulm (Germany); Texas A and M University Institute for Advanced Study (TIAS), Institute for Quantum Science and Engineering (IQSE), and Department of Physics and Astronomy, College Station, TX (United States); Schmiedmayer, Joerg [Vienna University of Technology, Vienna Center for Quantum Science and Technology, Institute of Atomic and Subatomic Physics, Vienna (Austria); Schuldt, Thilo [Institute of Space Systems, German Aerospace Center (DLR), Bremen (Germany); Schwab, Keith C. [California Institute of Technology, Applied Physics, Pasadena, CA (United States); Tajmar, Martin [Technische Universitaet Dresden, Institut fuer Luft- und Raumfahrttechnik, Dresden (Germany); Tino, Guglielmo M. [Universita di Firenze, Dipartimento di Fisica e Astronomia and LENS, INFN, Sesto Fiorentino, Firenze (Italy); Ulbricht, Hendrik [University of Southampton, Physics and Astronomy, Southampton (United Kingdom); Ursin, Rupert [Austrian Academy of Sciences, Institute of Quantum Optics and Quantum Information (IQOQI), Vienna (Austria); Vedral, Vlatko [University of Oxford, Atomic and Laser Physics, Clarendon Laboratory, Oxford (United Kingdom); National University of Singapore, Center for Quantum Technologies, Singapore (SG)

    2016-12-15

    Do the laws of quantum physics still hold for macroscopic objects - this is at the heart of Schroedinger's cat paradox - or do gravitation or yet unknown effects set a limit for massive particles? What is the fundamental relation between quantum physics and gravity? Ground-based experiments addressing these questions may soon face limitations due to limited free-fall times and the quality of vacuum and microgravity. The proposed mission Macroscopic Quantum Resonators (MAQRO) may overcome these limitations and allow addressing such fundamental questions. MAQRO harnesses recent developments in quantum optomechanics, high-mass matter-wave interferometry as well as state-of-the-art space technology to push macroscopic quantum experiments towards their ultimate performance limits and to open new horizons for applying quantum technology in space. The main scientific goal is to probe the vastly unexplored 'quantum-classical' transition for increasingly massive objects, testing the predictions of quantum theory for objects in a size and mass regime unachievable in ground-based experiments. The hardware will largely be based on available space technology. Here, we present the MAQRO proposal submitted in response to the 4th Cosmic Vision call for a medium-sized mission (M4) in 2014 of the European Space Agency (ESA) with a possible launch in 2025, and we review the progress with respect to the original MAQRO proposal for the 3rd Cosmic Vision call for a medium-sized mission (M3) in 2010. In particular, the updated proposal overcomes several critical issues of the original proposal by relying on established experimental techniques from high-mass matter-wave interferometry and by introducing novel ideas for particle loading and manipulation. Moreover, the mission design was improved to better fulfill the stringent environmental requirements for macroscopic quantum experiments. (orig.)

  15. Special relativity - the foundation of macroscopic physics

    International Nuclear Information System (INIS)

    Dixon, W.G.

    1978-01-01

    This book aims to show that an understanding of the basic laws of macroscopic systems can be gained more easily within relativistic physics than within Newtonian physics. The unity of dynamics, thermodynamics and electromagnetism under the umbrella of special relativity is examined under chapter headings entitled: the physics of space and time, affine spaces in mathematics and physics, foundations of dynamics, relativistic simple fluids, and, electrodynamics of polarizable fluids. (U.K.)

  16. Testing quantum behaviour at the macroscopic level

    International Nuclear Information System (INIS)

    Ghirardi, G.C.

    1994-07-01

    We reconsider recent proposals to test macro realism versus quantum mechanics in experiments involving noninvasive measurement processes on a Squid. In spite of the fact that we are able to prove that the proposed experiments do not represent a test of macro realism but simply of macroscopic quantum coherence we call attention to their extreme conceptual relevance. We also discuss some recent criticisms which have been raised against the considered proposal and we show that they are not relevant. (author). 12 refs

  17. Microscopic and macroscopic models for pedestrian crowds

    OpenAIRE

    Makmul, Juntima

    2016-01-01

    This thesis is concerned with microscopic and macroscopic models for pedes- trian crowds. In the first chapter, we consider pedestrians exit choices and model human behaviour in an evacuation process. Two microscopic models, discrete and continuous, are studied in this chapter. The former is a cellular automaton model and the latter is a social force model. Different numerical test cases are investigated and their results are compared. In chapter 2, a hierarchy of models for...

  18. Macroscopic acoustoelectric charge transport in graphene

    Science.gov (United States)

    Bandhu, L.; Lawton, L. M.; Nash, G. R.

    2013-09-01

    We demonstrate macroscopic acoustoelectric transport in graphene, transferred onto piezoelectric lithium niobate substrates, between electrodes up to 500 μm apart. Using double finger interdigital transducers we have characterised the acoustoelectric current as a function of both surface acoustic wave intensity and frequency. The results are consistent with a relatively simple classical relaxation model, in which the acoustoelectric current is proportional to both the surface acoustic wave intensity and the attenuation of the wave caused by the charge transport.

  19. Thermomechanical macroscopic model of shape memory alloys

    International Nuclear Information System (INIS)

    Volkov, A.E.; Sakharov, V.Yu.

    2003-01-01

    The phenomenological macroscopic model of the mechanical behaviour of the titanium nickelide-type shape memory alloys is proposed. The model contains as a parameter the average phase shear deformation accompanying the martensite formation. It makes i possible to describe correctly a number of functional properties of the shape memory alloys, in particular, the pseudoelasticity ferroplasticity, plasticity transformation and shape memory effects in the stressed and unstressed samples [ru

  20. Macroscopic behaviour of a charged Boltzmann gas

    International Nuclear Information System (INIS)

    Banyai, L.; Gartner, P.; Protopopescu, V.

    1980-08-01

    We consider a classical charged gas (with self-consistent Coulomb interaction) described by a solvable linearized Boltzman equation with thermaljzation on unifopmly distributed scatterers. It is shown that jf one scales the time t, the reciprocal space coordinate k vector and the Debye length l as lambda 2 t, k vector/lambda, lambda l respectively, in the lambda→infinity limit the charge density is equal to the solution of the corresponding diffusion-conduction (macroscopic) equation. (author)

  1. Active Polar Two-Fluid Macroscopic Dynamics

    Science.gov (United States)

    Pleiner, Harald; Svensek, Daniel; Brand, Helmut R.

    2014-03-01

    We study the dynamics of systems with a polar dynamic preferred direction. Examples include the pattern-forming growth of bacteria (in a solvent, shoals of fish (moving in water currents), flocks of birds and migrating insects (flying in windy air). Because the preferred direction only exists dynamically, but not statically, the macroscopic variable of choice is the macroscopic velocity associated with the motion of the active units. We derive the macroscopic equations for such a system and discuss novel static, reversible and irreversible cross-couplings connected to this second velocity. We find a normal mode structure quite different compared to the static descriptions, as well as linear couplings between (active) flow and e.g. densities and concentrations due to the genuine two-fluid transport derivatives. On the other hand, we get, quite similar to the static case, a direct linear relation between the stress tensor and the structure tensor. This prominent ``active'' term is responsible for many active effects, meaning that our approach can describe those effects as well. In addition, we also deal with explicitly chiral systems, which are important for many active systems. In particular, we find an active flow-induced heat current specific for the dynamic chiral polar order.

  2. Macroscopic nonclassical-state preparation via postselection

    Science.gov (United States)

    Montenegro, Víctor; Coto, Raúl; Eremeev, Vitalie; Orszag, Miguel

    2017-11-01

    Macroscopic quantum superposition states are fundamental to test the classical-quantum boundary and present suitable candidates for quantum technologies. Although the preparation of such states has already been realized, the existing setups commonly consider external driving and resonant interactions, predominantly by considering Jaynes-Cummings-like and beam-splitter-like interactions, as well as the nonlinear radiation pressure interaction in cavity optomechanics. In contrast to previous works on the matter, we propose a feasible probabilistic scheme to generate a macroscopic mechanical qubit, as well as phononic Schrödinger's cat states with no need of any energy exchange with the macroscopic mechanical oscillator. Essentially, we investigate an open dispersive spin-mechanical system in the absence of any external driving under nonideal conditions, such as the detrimental effects due to the oscillator and spin energy losses in a thermal bath at nonzero temperature. In our work, we show that the procedure to generate the mechanical qubit state is solely based on spin postselection in the weak to moderate coupling regime. Finally, we demonstrate that the mechanical superposition is related to the amplification of the mean values of the mechanical quadratures as they maximize the quantum coherence.

  3. Scanner-based macroscopic color variation estimation

    Science.gov (United States)

    Kuo, Chunghui; Lai, Di; Zeise, Eric

    2006-01-01

    Flatbed scanners have been adopted successfully in the measurement of microscopic image artifacts, such as granularity and mottle, in print samples because of their capability of providing full color, high resolution images. Accurate macroscopic color measurement relies on the use of colorimeters or spectrophotometers to provide a surrogate for human vision. The very different color response characteristics of flatbed scanners from any standard colorimetric response limits the utility of a flatbed scanner as a macroscopic color measuring device. This metamerism constraint can be significantly relaxed if our objective is mainly to quantify the color variations within a printed page or between pages where a small bias in measured colors can be tolerated as long as the color distributions relative to the individual mean values is similar. Two scenarios when converting color from the device RGB color space to a standardized color space such as CIELab are studied in this paper, blind and semi-blind color transformation, depending on the availability of the black channel information. We will show that both approaches offer satisfactory results in quantifying macroscopic color variation across pages while the semi-blind color transformation further provides fairly accurate color prediction capability.

  4. Pathways toward understanding Macroscopic Quantum Phenomena

    International Nuclear Information System (INIS)

    Hu, B L; Subaşi, Y

    2013-01-01

    Macroscopic quantum phenomena refer to quantum features in objects of 'large' sizes, systems with many components or degrees of freedom, organized in some ways where they can be identified as macroscopic objects. This emerging field is ushered in by several categories of definitive experiments in superconductivity, electromechanical systems, Bose-Einstein condensates and others. Yet this new field which is rich in open issues at the foundation of quantum and statistical physics remains little explored theoretically (with the important exception of the work of A J Leggett [1], while touched upon or implied by several groups of authors represented in this conference. Our attitude differs in that we believe in the full validity of quantum mechanics stretching from the testable micro to meso scales, with no need for the introduction of new laws of physics.) This talk summarizes our thoughts in attempting a systematic investigation into some key foundational issues of quantum macroscopic phenomena, with the goal of ultimately revealing or building a viable theoretical framework. Three major themes discussed in three intended essays are the large N expansion [2], the correlation hierarchy [3] and quantum entanglement [4]. We give a sketch of the first two themes and then discuss several key issues in the consideration of macro and quantum, namely, a) recognition that there exist many levels of structure in a composite body and only by judicious choice of an appropriate set of collective variables can one give the best description of the dynamics of a specific level of structure. Capturing the quantum features of a macroscopic object is greatly facilitated by the existence and functioning of these collective variables; b) quantum entanglement, an exclusively quantum feature [5], is known to persist to high temperatures [6] and large scales [7] under certain conditions, and may actually decrease with increased connectivity in a quantum network [8]. We use entanglement as a

  5. Experimental demonstration of macroscopic quantum coherence in Gaussian states

    DEFF Research Database (Denmark)

    Marquardt, C.; Andersen, Ulrik Lund; Leuchs, G.

    2007-01-01

    We witness experimentally the presence of macroscopic coherence in Gaussian quantum states using a recently proposed criterion [E. G. Cavalcanti and M. D. Reid, Phys. Rev. Lett. 97 170405 (2006)]. The macroscopic coherence stems from interference between macroscopically distinct states in phase...

  6. [The story of K.V. Tjellesen].

    Science.gov (United States)

    Clemmensen, Peter

    2005-01-01

    This is the story about a Danish pharmaceutical wholesaler. The story begins in 1909 in some basement rooms located in Vester Boulevard 42 (which was later to become the Boulevard of H.C. Andersen) in Copenhagen. The founder of the company, pharmacist Knud Valdemar Tjellesen, lived in the very same building. In the beginning, the company mainly sold chemicals and produced and sold chemical-technical products. In 1930, K.V. Tjellesen became the proprietor of the pharmacy Sct. Johannes Apotek situated in Fredensgade 5, Nørrebro in Copenhagen. The company then moved into some offices that were located just behind the pharmacy. Already in 1918, K.V. Tjellesen traded pharmaceutical specialties, which were imported, to a certain extent, from Germany through a purchasing office in Hamburg. In 1938, the son of Knud Valdemar Tjellesen, pharmacist Paul Tjellesen, joined the wholesale company charged with the primary task of intensifying the sale of the company's international agency products. At the same time, the general partnership K.V. Tjellesen was founded. In the time leading up to the Second World War and during this time, business was of course complicated by currency and import restrictions, and it was very difficult to make deliveries to the pharmacies. In Copenhagen, the articles were delivered by 10-12 bicycle delivery boys. In the beginning, the wholesale company mainly catered for Copenhagen and Zealand, but due to the excellent performance of Paul Tjellesen, more and more customers emerged in the rest of the country. In 1954, the company moved to Niels Ebbesens Vej 29 in Frederiksberg given the need for larger facilities. In 1963, an increased space requirement, once again, forced the company to buy one of the neighbouring buildings on Niels Ebbesens Vej and H.C. Orsteds Vej. For many years after, H.C. Orsteds Vej 22 was the official address of the company. After more than 45 years in the company, Paul Tjellesen agreed with his son-in-law Peter Sch

  7. Solution of K-V envelope equations

    International Nuclear Information System (INIS)

    Anderson, O.A.

    1995-04-01

    The envelope equations for a KV beam with space charge have been analyzed systematically by an e expansion followed by integrations. The focusing profile as a function of axial length is assumed to be symmetric but otherwise arbitrary. Given the bean current, emittance, and peak focusing field, we find the envelopes a(s) and b(s) and obtain , a max , σ, and σ 0 . Explicit results are presented for various truncations of the expansion. The zeroth order results correspond to those from the well-known smooth approximation; the same convenient format is retained for the higher order cases. The first order results, involving single correction terms, give 3--10 times better accuracy and are good to ∼1% at σ 0 = 70 degree. Third order gives a factor of 10--30 improvement over the smooth approximation and derived quantities accurate to ∼1% at σ 0 = 112 degree. The first order expressions are convenient design tools. They lend themselves to variable energy problems and have been applied to the design, construction, and testing of ESQ accelerators at LBL

  8. The macroscopic harmonic oscillator and quantum measurements

    International Nuclear Information System (INIS)

    Hayward, R.W.

    1982-01-01

    A quantum mechanical description of a one-dimensional macroscopic harmonic oscillator interacting with its environment is given. Quasi-coherent states are introduced to serve as convenient basis states for application of a density matrix formalism to characterize the system. Attention is given to the pertinent quantum limits to the precision of measurement of physical observables that may provide some information on the nature of a weak classical force interacting with the oscillator. A number of ''quantum nondemolition'' schemes proposed by various authors are discussed. (Auth.)

  9. Macroscopic quantum tunneling of the magnetic moment

    Science.gov (United States)

    Tejada, J.; Hernandez, J. M.; del Barco, E.

    1999-05-01

    In this paper we review the work done on magnetic relaxation during the last 10 years on both single-domain particles and magnetic molecules and its contribution to the discovery of quantum tunneling of the magnetic moment (Chudnovsky and Tejada, Macroscopic Quantum tunneling of the Magnetic moment, Cambridge University press, Cambridge, 1998). We present first the theoretical expressions and their connection to quantum relaxation and secondly, we show and discuss the experimental results. Finally, we discuss very recent hysteresis data on Mn 12Ac molecules at extremely large sweeping rate for the external magnetic field which suggest the existence of quantum spin—phonon avalanches.

  10. Compressor Has No Moving Macroscopic Parts

    Science.gov (United States)

    Gasser, Max

    1995-01-01

    Compressor containing no moving macroscopic parts functions by alternating piston and valve actions of successive beds of magnetic particles. Fabricated easily because no need for precisely fitting parts rotating or sliding on each other. Also no need for lubricant fluid contaminating fluid to be compressed. Compressor operates continuously, eliminating troublesome on/off cycling of other compressors, and decreasing consumption of energy. Phased cells push fluid from bottom to top, adding increments of pressure. Each cell contains magnetic powder particles loose when electromagnet coil deenergized, but tightly packed when coil energized.

  11. Macroscopic reality and the dynamical reduction program

    International Nuclear Information System (INIS)

    Ghirardi, G.C.

    1995-10-01

    With reference to recently proposed theoretical models accounting for reduction in terms of a unified dynamics governing all physical processes, we analyze the problem of working out a worldview accommodating our knowledge about natural phenomena. We stress the relevant conceptual differences between the considered models and standard quantum mechanics. In spite of the fact that both theories describe individual physical systems within a genuine Hilbert space framework, the nice features of spontaneous reduction theories drastically limit the class of states which are dynamically stable. This allows one to work out a description of the world in terms of a mass density function in ordinary configuration space. A topology based on this function and differing radically from the one characterizing the Hilbert space is introduced and in terms of it the idea of similarity of macroscopic situations is made precise. Finally it is shown how the formalism and the proposed interpretation yield a natural criterion for establishing the psychophysical parallelism. The conclusion is that, within the considered theoretical models and at the nonrelativistic level, one can satisfy all sensible requirements for a consistent, unified, and objective description of reality at the macroscopic level. (author). 16 refs

  12. Macroscopic description of isoscalar giant multipole resonances

    International Nuclear Information System (INIS)

    Nix, J.R.; Sierk, A.J.

    1980-01-01

    On the basis of a simple macroscopic model, we calculate the isoscalar giant-resonance energy as a function of mass number and multipole degree. The restoring force is determined from the distortion of the Fermi surface, and the inertia is determined for the incompressible, irrotational flow of nucleons with unit effective mass. With no adjustable parameters, the resulting closed expression reproduces correctly the available experimental data, namely the magnitude and dependence upon mass number of the giant quadrupole energy and the magnitude of the giant octupole energy for 208 Pb. We also calculate the isoscalar giant-resonance width as a function of mass number and multipole degree for various macroscopic damping mechanisms, including two-body viscosity, one-body dissipation, and modified one-body dissipation. None of these damping mechanisms reproduces correctly all features of the available experimental data, namely the magnitude and dependence upon mass number of the giant quadrupole width and the magnitude of the giant octupole width for 208 Pb

  13. Macroscopic quantum tunneling in Mn12-acetat

    International Nuclear Information System (INIS)

    Beiter, J.; Reissner, M.; Hilscher, G.; Steiner, W.; Pajic, D.; Zadro, K.; Bartel, M.; Linert, W.

    2004-01-01

    Molecules provide the exciting opportunity to study magnetism on the passage from atomic to macroscopic level. One of the most interesting effects in such mesoscopic systems is the appearance of quantum tunnelling of magnetization (MQT) at low temperatures. In the last decade molecular chemistry has had a large impact in this field by providing new single molecule magnets. They consist of small clusters exhibiting superparamagnetic behavior, similar to that of conventional nanomagnetic particles. The advantage of these new materials is that they form macroscopic samples consisting of regularly arranged small identical high-spin clusters which are widely separated by organic molecules. The lack of distributions in size and shape of the magnetic clusters and the very weak intercluster interaction lead in principle to only one barrier for the spin reversal. We present detailed magnetic investigations on a Mn 12 -ac single crystal. In this compound the tetragonal ordered clusters consist of a central tetrahedron of four Mn 4+ (S = 3/2) atoms surrounded by eight Mn 3+ (S = 2) atoms with antiparallel oriented spins, leading to an overall spin moment of S = 10. In the hysteresis loops nine different jumps at regularly spaced fields are identified in the investigated temperature range (1.5 < T < 3 K). At these fields the relaxation of moment due to thermal activation is superimposed by strong quantum tunnelling. In lowering the temperature the time dependence changes from thermally activated to thermally assisted tunnelling. (author)

  14. Macroscopic effects of the quantum trace anomaly

    International Nuclear Information System (INIS)

    Mottola, Emil; Vaulin, Ruslan

    2006-01-01

    The low energy effective action of gravity in any even dimension generally acquires nonlocal terms associated with the trace anomaly, generated by the quantum fluctuations of massless fields. The local auxiliary field description of this effective action in four dimensions requires two additional scalar fields, not contained in classical general relativity, which remain relevant at macroscopic distance scales. The auxiliary scalar fields depend upon boundary conditions for their complete specification, and therefore carry global information about the geometry and macroscopic quantum state of the gravitational field. The scalar potentials also provide coordinate invariant order parameters describing the conformal behavior and divergences of the stress tensor on event horizons. We compute the stress tensor due to the anomaly in terms of its auxiliary scalar potentials in a number of concrete examples, including the Rindler wedge, the Schwarzschild geometry, and de Sitter spacetime. In all of these cases, a small number of classical order parameters completely determine the divergent behaviors allowed on the horizon, and yield qualitatively correct global approximations to the renormalized expectation value of the quantum stress tensor

  15. Measurement contextuality is implied by macroscopic realism

    International Nuclear Information System (INIS)

    Chen Zeqian; Montina, A.

    2011-01-01

    Ontological theories of quantum mechanics provide a realistic description of single systems by means of well-defined quantities conditioning the measurement outcomes. In order to be complete, they should also fulfill the minimal condition of macroscopic realism. Under the assumption of outcome determinism and for Hilbert space dimension greater than 2, they were all proved to be contextual for projective measurements. In recent years a generalized concept of noncontextuality was introduced that applies also to the case of outcome indeterminism and unsharp measurements. It was pointed out that the Beltrametti-Bugajski model is an example of measurement noncontextual indeterminist theory. Here we provide a simple proof that this model is the only one with such a feature for projective measurements and Hilbert space dimension greater than 2. In other words, there is no extension of quantum theory providing more accurate predictions of outcomes and simultaneously preserving the minimal labeling of events through projective operators. As a corollary, noncontextuality for projective measurements implies noncontextuality for unsharp measurements. By noting that the condition of macroscopic realism requires an extension of quantum theory, unless a breaking of unitarity is invoked, we arrive at the conclusion that the only way to solve the measurement problem in the framework of an ontological theory is by relaxing the hypothesis of measurement noncontextuality in its generalized sense.

  16. Macroscopic reality and the dynamical reduction program

    Energy Technology Data Exchange (ETDEWEB)

    Ghirardi, G C

    1995-10-01

    With reference to recently proposed theoretical models accounting for reduction in terms of a unified dynamics governing all physical processes, we analyze the problem of working out a worldview accommodating our knowledge about natural phenomena. We stress the relevant conceptual differences between the considered models and standard quantum mechanics. In spite of the fact that both theories describe individual physical systems within a genuine Hilbert space framework, the nice features of spontaneous reduction theories drastically limit the class of states which are dynamically stable. This allows one to work out a description of the world in terms of a mass density function in ordinary configuration space. A topology based on this function and differing radically from the one characterizing the Hilbert space is introduced and in terms of it the idea of similarity of macroscopic situations is made precise. Finally it is shown how the formalism and the proposed interpretation yield a natural criterion for establishing the psychophysical parallelism. The conclusion is that, within the considered theoretical models and at the nonrelativistic level, one can satisfy all sensible requirements for a consistent, unified, and objective description of reality at the macroscopic level. (author). 16 refs.

  17. First 735 kV transmission, Manicouagan, Montreal

    Energy Technology Data Exchange (ETDEWEB)

    Cahill, L

    1964-11-01

    The 735 kV transmission network of Hydro Quebec is described giving reasons for choice of voltage, stability factors level of insulation, disposition of conductors, insulators, equipment used and state of readiness of the project.

  18. APPLICATION OF SSSC TO THE 330kV NIGERIAN ...

    African Journals Online (AJOL)

    HOD

    2,3 DEPARTMENT OF ELECTRONIC AND ELECTRICAL ENGR., FEDERAL POLYTECHNIC EDE, ... Longitudinal power systems of Nigerian 330 kV transmission network have steady-state ..... C tr ller ” Unpublish Master Thesis Submitted to.

  19. Differential expression of the Kv1 voltage-gated potassium channel family in the rat nephron.

    Science.gov (United States)

    Carrisoza-Gaytán, Rolando; Salvador, Carolina; Diaz-Bello, Beatriz; Escobar, Laura I

    2014-10-01

    Several potassium (K(+)) channels contribute to maintaining the resting membrane potential of renal epithelial cells. Apart from buffering the cell membrane potential and cell volume, K(+) channels allow sodium reabsorption in the proximal tubule (PT), K(+) recycling and K(+) reabsorption in the thick ascending limb (TAL) and K(+) secretion and K(+) reabsorption in the distal convoluted tubule (DCT), connecting tubule (CNT) and collecting duct. Previously, we identified Kv.1.1, Kv1.3 and Kv1.6 channels in collecting ducts of the rat inner medulla. We also detected intracellular Kv1.3 channel in the acid secretory intercalated cells, which is trafficked to the apical membrane in response to dietary K(+) to function as a secretory K(+) channel. In this work we sought to characterize the expression of all members of the Kv1 family in the rat nephron. mRNA and protein expression were detected for all Kv1 channels. Immunoblots identified differential expression of each Kv1 in the cortex, outer and inner medulla. Immunofluorescence labeling detected Kv1.5 in Bowman´s capsule and endothelial cells and Kv1.7 in podocytes, endothelial cells and macula densa in glomeruli; Kv1.4, Kv1.5 and Kv1.7 in PT; Kv1.2, Kv1.4 and Kv1.6 in TAL; Kv1.1, Kv1.4 and Kv1.6 in DCT and CNT and Kv1.3 in DCT, and all the Kv1 family in the cortical and medullary collecting ducts. Recently, some hereditary renal syndromes have been attributed to mutations in K(+) channels. Our results expand the repertoire of K(+) channels that contribute to K(+) homeostasis to include the Kv1 family.

  20. Inactivation as a new regulatory mechanism for neuronal Kv7 channels

    DEFF Research Database (Denmark)

    Jensen, Henrik Sindal; Grunnet, Morten; Olesen, Søren-Peter

    2007-01-01

    neuronal channels and are important for controlling excitability. Kv7.1 channels have been considered the only Kv7 channels to undergo inactivation upon depolarization. However, here we demonstrate that inactivation is also an intrinsic property of Kv7.4 and Kv7.5 channels, which inactivate to a larger...

  1. The acrylamide (S)-1 differentially affects Kv7 (KCNQ) potassium channels

    DEFF Research Database (Denmark)

    Bentzen, Bo Hjorth; Schmitt, Nicole; Calloe, Kirstine

    2006-01-01

    The family of Kv7 (KCNQ) potassium channels consists of five members. Kv7.2 and 3 are the primary molecular correlates of the M-current, but also Kv7.4 and Kv7.5 display M-current characteristics. M-channel modulators include blockers (e.g., linopirdine) for cognition enhancement and openers (e.g...

  2. Development of 66 kV/6.9 kV 2 MV A prototype HTS power transformer

    International Nuclear Information System (INIS)

    Bohno, T.; Tomioka, A.; Imaizumi, M.; Sanuki, Y.; Yamamoto, T.; Yasukawa, Y.; Ono, H.; Yagi, Y.; Iwadate, K.

    2005-01-01

    We have developed the technology of the producing a HTS magnet for the power transformer. Three subjects have been mainly studied, high voltage technologies, large current and low AC loss technologies and sub-cooling system technologies to establish the technology of 66 kV/6.9 kV 10 MV A class HTS power transformer. In order to verify the validity of elemental technologies, such as high voltage technologies, large current and low AC loss technologies and sub-cooling system technologies, single-phase 2 MV A class 66 kV/6.9 kV prototype HTS transformer was manufactured and tested. In the load loss (AC loss) measurement, it was obtained that the measured value of 633 W was almost corresponding to the calculated value of 576 W at the rated operation of 2 MV A. Moreover, the breakdown was not found all voltage withstand test. These test results indicate that elemental technologies were established for the development of 66 kV/6.9 kV 10 MV A class HTS power transformer

  3. Partitioning a macroscopic system into independent subsystems

    Science.gov (United States)

    Delle Site, Luigi; Ciccotti, Giovanni; Hartmann, Carsten

    2017-08-01

    We discuss the problem of partitioning a macroscopic system into a collection of independent subsystems. The partitioning of a system into replica-like subsystems is nowadays a subject of major interest in several fields of theoretical and applied physics. The thermodynamic approach currently favoured by practitioners is based on a phenomenological definition of an interface energy associated with the partition, due to a lack of easily computable expressions for a microscopic (i.e. particle-based) interface energy. In this article, we outline a general approach to derive sharp and computable bounds for the interface free energy in terms of microscopic statistical quantities. We discuss potential applications in nanothermodynamics and outline possible future directions.

  4. Quantum teleportation between stationary macroscopic objects

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Xiao-Hui; Yuan, Zhen-Sheng; Pan, Jian-Wei [Physikalisches Institut, Universitaet Heidelberg (Germany); Hefei National Laboratory for Physical Sciences at Microscale, Department of Modern Physics, University of Science and Technology of China, Hefei (China); Xu, Xiao-Fan [Physikalisches Institut, Universitaet Heidelberg (Germany); Li, Che-Ming [Physikalisches Institut, Universitaet Heidelberg (Germany); Department of Physics, National Center for Theoretical Sciences, National Cheng Kung University, Tainan (China)

    2010-07-01

    Quantum teleportation is a process to transfer a quantum state of an object without transferring the state carrier itself. So far, most of the teleportation experiments realized are within the photonic regime. For the teleportation of stationary states, the largest system reported is a single ion. We are now performing an experiment to teleport the state of an macroscopic atomic cloud which consists about 10{sup 6} single atoms. In our experiment two atomic ensembles are utilized. In the first ensemble A we prepare the collective atomic state to be teleported using the quantum feedback technique. The second ensemble B is utilized to generate entanglement between it collective state with a scattered single-photon. Teleportation is realized by converting the atomic state of A to a single-photon and making a Bell state measurement with the scattered single-photon from ensemble B.

  5. Macroscopic balance model for wave rotors

    Science.gov (United States)

    Welch, Gerard E.

    1996-01-01

    A mathematical model for multi-port wave rotors is described. The wave processes that effect energy exchange within the rotor passage are modeled using one-dimensional gas dynamics. Macroscopic mass and energy balances relate volume-averaged thermodynamic properties in the rotor passage control volume to the mass, momentum, and energy fluxes at the ports. Loss models account for entropy production in boundary layers and in separating flows caused by blade-blockage, incidence, and gradual opening and closing of rotor passages. The mathematical model provides a basis for predicting design-point wave rotor performance, port timing, and machine size. Model predictions are evaluated through comparisons with CFD calculations and three-port wave rotor experimental data. A four-port wave rotor design example is provided to demonstrate model applicability. The modeling approach is amenable to wave rotor optimization studies and rapid assessment of the trade-offs associated with integrating wave rotors into gas turbine engine systems.

  6. Macroscopic quantum tunneling in a dc SQUID

    International Nuclear Information System (INIS)

    Chen, Y.C.

    1986-01-01

    The theory of macroscopic quantum tunneling is applied to a current-biased dc SQUID whose dynamics can be described by a two-dimensional mechanical system with a dissipative environment. Based on the phenomenological model proposed by Caldeira and Leggett, the dissipative environment is represented by a set of harmonic oscillators coupling to the system. After integrating out the environmental degrees of freedom, an effective Euclidean action is found for the two-dimensional system. The action is used to provide the quantum tunneling rate formalism for the dc SQUID. Under certain conditions, the tunneling rate reduces to that of a single current-biased Josephson junction with an adjustable effective critical current

  7. Models for universal reduction of macroscopic quantum fluctuations

    International Nuclear Information System (INIS)

    Diosi, L.

    1988-10-01

    If quantum mechanics is universal, then macroscopic bodies would, in principle, possess macroscopic quantum fluctuations (MQF) in their positions, orientations, densities etc. Such MQF, however, are not observed in nature. The hypothesis is adopted that the absence of MQF is due to a certain universal mechanism. Gravitational measures were applied for reducing MQF of the mass density. This model leads to classical trajectories in the macroscopic limit of translational motion. For massive objects, unwanted macroscopic superpositions of quantum states will be destroyed within short times. (R.P.) 34 refs

  8. Major Refit for CERN's 400 kV Substation

    CERN Multimedia

    2001-01-01

    The 400 kV substation on the Prévessin site brings in the electricity that powers CERN's accelerators and the majority of the Laboratory's installations. It was originally built in the 1970s for the SPS, and is one of only five privately owned 400 kV sub-stations in France. Three of the others belong to the national railway company, SNCF, supplying the Paris-Marseilles TGV line, the other is at the Cadarache research centre near mouth of the Rhone. After nearly thirty years of service, CERN's substation has just undergone a complete overhaul. The new main 18 kV switchboard for the SPS pulsed network. The electricity supply for the original Prévessin substation was from the 400 kV EDF network, delivered through three 90 MW transformers at 18 kV to the SPS pulsed network, With the arrival of LEP, two 110 MW transformers were added to supply the new accelerator. Now, as CERN gears up for the LHC, additional pulsed power capacity is needed to supply the transfer lines carrying protons from...

  9. HVDC transmission preferred to 750 kV ac

    Energy Technology Data Exchange (ETDEWEB)

    1965-06-25

    It is unlikely that there will be a need in Britain for ac transmission voltages above 400 kV. But with the growing load density in the large conurbations with no possibility of local generation, high voltage dc transmission is likely to be most useful. It was concluded that by 1971 the 400 kV supergrid would be nation-wide and 6,200 circuit miles should be in service. With the expansion to accommodate the large new generating stations, the 400 kV supergrid would become an extremely high power distribution network rather than a transmission system. A higher voltage for transmission is outside the rational limit of speculation for a country the size of Britain.

  10. Skeletal muscle Kv7 (KCNQ) channels in myoblast differentiation and proliferation

    International Nuclear Information System (INIS)

    Roura-Ferrer, Meritxell; Sole, Laura; Martinez-Marmol, Ramon; Villalonga, Nuria; Felipe, Antonio

    2008-01-01

    Voltage-dependent K + channels (Kv) are involved in myocyte proliferation and differentiation by triggering changes in membrane potential and regulating cell volume. Since Kv7 channels may participate in these events, the purpose of this study was to investigate whether skeletal muscle Kv7.1 and Kv7.5 were involved during proliferation and myogenesis. Here we report that, while myotube formation did not regulate Kv7 channels, Kv7.5 was up-regulated during cell cycle progression. Although, Kv7.1 mRNA also increased during the G 1 -phase, pharmacological evidence mainly involves Kv7.5 in myoblast growth. Our results indicate that the cell cycle-dependent expression of Kv7.5 is involved in skeletal muscle cell proliferation

  11. Cloud Macroscopic Organization: Order Emerging from Randomness

    Science.gov (United States)

    Yuan, Tianle

    2011-01-01

    Clouds play a central role in many aspects of the climate system and their forms and shapes are remarkably diverse. Appropriate representation of clouds in climate models is a major challenge because cloud processes span at least eight orders of magnitude in spatial scales. Here we show that there exists order in cloud size distribution of low-level clouds, and that it follows a power-law distribution with exponent gamma close to 2. gamma is insensitive to yearly variations in environmental conditions, but has regional variations and land-ocean contrasts. More importantly, we demonstrate this self-organizing behavior of clouds emerges naturally from a complex network model with simple, physical organizing principles: random clumping and merging. We also demonstrate symmetry between clear and cloudy skies in terms of macroscopic organization because of similar fundamental underlying organizing principles. The order in the apparently complex cloud-clear field thus has its root in random local interactions. Studying cloud organization with complex network models is an attractive new approach that has wide applications in climate science. We also propose a concept of cloud statistic mechanics approach. This approach is fully complementary to deterministic models, and the two approaches provide a powerful framework to meet the challenge of representing clouds in our climate models when working in tandem.

  12. Searching for the nanoscopic–macroscopic boundary

    Energy Technology Data Exchange (ETDEWEB)

    Velásquez, E.A. [GICM and GES Groups, Instituto de Física-FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21 Medellín (Colombia); Grupo de Investigación en Modelamiento y Simulación Computacional, Universidad de San Buenaventura Sec. Medellín, A.A. 5222, Medellín (Colombia); Altbir, D. [Departamento de Física, Universidad de Santiago de Chile (USACH), CEDENNA, Santiago (Chile); Mazo-Zuluaga, J. [GICM and GES Groups, Instituto de Física-FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21 Medellín (Colombia); Duque, L.F. [GICM and GES Groups, Instituto de Física-FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21 Medellín (Colombia); Grupo de Física Teórica, Aplicada y Didáctica, Facultad de Ciencias Exactas y Aplicadas Instituto Tecnológico Metropolitano, Medellín (Colombia); Mejía-López, J., E-mail: jmejia@puc.cl [Facultad de Física, Pontificia Universidad Católica de Chile, CEDENNA, Santiago (Chile)

    2013-12-15

    Several studies have focused on the size-dependent properties of elements, looking for a unique definition of the nanoscopic–macroscopic boundary. By using a novel approach consisting of an energy variational method combined with a quantum Heisenberg model, here we address the size at which the ordering temperature of a magnetic nanoparticle reaches its bulk value. We consider samples with sizes in the range 1–500 nm, as well as several geometries and crystalline lattices and observe that, contrarily to what is commonly argued, the nanoscopic-microscopic boundary depends on both factors: shape and crystalline structure. This suggests that the surface-to-volume ratio is not the unique parameter that defines the behavior of a nanometric sample whenever its size increases reaching the bulk dimension. Comparisons reveal very good agreement with experimental evidence with differences less than 2%. Our results have broad implications for practical issues in measurements on systems at the nanometric scale. - Highlights: • A novel quantum-Heisenberg variational energy method is implemented. • The asymptotic behavior toward the thermodynamic limit is explored. • An important dependence of the nano-bulk boundary on the geometry is found. • And also an important dependence on the crystalline lattice. • We obtain a very good agreement with experimental evidence with differences <2%.

  13. Adiabatic process reversibility: microscopic and macroscopic views

    International Nuclear Information System (INIS)

    Anacleto, Joaquim; Pereira, Mario G

    2009-01-01

    The reversibility of adiabatic processes was recently addressed by two publications. In the first (Miranda 2008 Eur. J. Phys. 29 937-43), an equation was derived relating the initial and final volumes and temperatures for adiabatic expansions of an ideal gas, using a microscopic approach. In that relation the parameter r accounts for the process reversibility, ranging between 0 and 1, which corresponds to the free and reversible expansion, respectively. In the second (Anacleto and Pereira 2009 Eur. J. Phys. 30 177-83), the authors have shown that thermodynamics can effectively and efficiently be used to obtain the general law for adiabatic processes carried out by an ideal gas, including compressions, for which r≥1. The present work integrates and extends the aforementioned studies, providing thus further insights into the analysis of the adiabatic process. It is shown that Miranda's work is wholly valid for compressions. In addition, it is demonstrated that the adiabatic reversibility coefficient given in terms of the piston velocity and the root mean square velocity of the gas particles is equivalent to the macroscopic description, given just by the quotient between surroundings and system pressure values. (letters and comments)

  14. Theory of superfluidity macroscopic quantum waves

    International Nuclear Information System (INIS)

    Ventura, I.

    1978-10-01

    A new description of superfluidity is proposed, based upon the fact that Bogoliubov's theory of superfluidity exhibits some so far unsuspected macroscopic quantum waves (MQWs), which have a topological nature and travel within the fluid at subsonic velocities. To quantize the bounded quasi-particles the field theoretic version of the Bohr-Sommerfeld quantization rule, is employed and also resort to a variational computation. In an instantaneous configuration the MQWs cut the condensate into blocks of phase, providing, by analogy with ferromagnetism, a nice explanation of what could be the lambda-transition. A crude estimate of the critical temperature gives T sub(c) approximately equal to 2-4K. An attempt is made to understand Tisza's two-fluid model in terms of the MQWs, and we rise the conjecture that they play an important role in the motion of second. We present also a qualitative prediction concerning to the behavior of the 'phononroton' peak below 1.0K, and propose two experiments to look for MQWs [pt

  15. Investigation of dissipative forces near macroscopic media

    International Nuclear Information System (INIS)

    Becker, R.S.

    1982-12-01

    The interaction of classical charged particles with the fields they induce in macroscopic dielectric media is investigated. For 10- to 1000-eV electrons, the angular perturbation of the trajectory by the image potential for surface impact parameters of 50 to 100 A is shown to be of the order of 0.001 rads over a distance of 100 A. The energy loss incurred by low-energy particles due to collective excitations such as surface plasmons is shown to be observable with a transition probability of 0.01 to 0.001 (Becker, et al., 1981b). The dispersion of real surface plasmon modes in planar and cylindrical geometries is discussed and is derived for pinhole geometry described in terms of a single-sheeted hyperboloid of revolution. An experimental apparatus for the measurement of collective losses for medium-energy electrons translating close to a dielectric surface is described and discussed. Data showing such losses at electron energies of 500 to 900 eV in silver foils containing many small apertures are presented and shown to be in good agreement with classical stopping power calculations and quantum mechanical calculations carried out in the low-velocity limit. The data and calculations are compared and contrasted with earlier transmission and reflection measurements, and the course of further investigation is discussed

  16. The Proell Effect: A Macroscopic Maxwell's Demon

    Science.gov (United States)

    Rauen, Kenneth M.

    2011-12-01

    Maxwell's Demon is a legitimate challenge to the Second Law of Thermodynamics when the "demon" is executed via the Proell effect. Thermal energy transfer according to the Kinetic Theory of Heat and Statistical Mechanics that takes place over distances greater than the mean free path of a gas circumvents the microscopic randomness that leads to macroscopic irreversibility. No information is required to sort the particles as no sorting occurs; the entire volume of gas undergoes the same transition. The Proell effect achieves quasi-spontaneous thermal separation without sorting by the perturbation of a heterogeneous constant volume system with displacement and regeneration. The classical analysis of the constant volume process, such as found in the Stirling Cycle, is incomplete and therefore incorrect. There are extra energy flows that classical thermo does not recognize. When a working fluid is displaced across a regenerator with a temperature gradient in a constant volume system, complimentary compression and expansion work takes place that transfers energy between the regenerator and the bulk gas volumes of the hot and cold sides of the constant volume system. Heat capacity at constant pressure applies instead of heat capacity at constant volume. The resultant increase in calculated, recyclable energy allows the Carnot Limit to be exceeded in certain cycles. Super-Carnot heat engines and heat pumps have been designed and a US patent has been awarded.

  17. Classical behaviour of macroscopic bodies and quantum measurements

    International Nuclear Information System (INIS)

    Ghirardi, G.; Rimini, A.; Weber, T.

    1986-01-01

    This report describes a recent attempt of giving a consistent and unified description of microscopic and macroscopic phenomena. The model presented in this paper exhibits the nice features of leaving unaltered the quantum description of microsystems and of accounting for the classical behaviour of the macroscopic objects when their dynamical evolution is consistently deduced from the dynamics of their elementary constituents

  18. Macroscopic quantum tunnelling in a current biased Josephson junction

    International Nuclear Information System (INIS)

    Martinis, J.M.; Devoret, M.H.; Clarke, J.; Urbina, C.

    1984-11-01

    We discuss in this work an attempt to answer experimentally the question: do macroscopic variables obey quantum mechanics. More precisely, this experiment deals with the question of quantum-mechanical tunnelling of a macroscopic variable, a subject related to the famous Schrodinger's cat problem in the theory of measurement

  19. Compact 250-kV injector system for PIGMI

    International Nuclear Information System (INIS)

    Hamm, R.W.; Stevens, R.R. Jr.; Mueller, D.W.; Lederer, H.M.

    1978-01-01

    A 250-kV proton injector to be used in the development of a linac suitable for medical applications has been constructed. This injector utilizes a spherical Pierce geometry to produce a converging beam. A gas insulated accelerating column is cantilevered on a grounded vacuum system, with a separate high voltage equipment dome connected to a 300-kV Cockcroft-Walton power supply. The injector can be operated locally or remotely, with the remote control accomplished by a microprocessor system linked to a central control minicomputer. This injector has been designed as a low-cost compact system. The design details and the data obtained during initial operation are presented

  20. Towards a theory of macroscopic gravity

    International Nuclear Information System (INIS)

    Zalaletdinov, R.M.

    1993-01-01

    By averaging out Cartan's structure equations for a four-dimensional Riemannian space over space regions, the structure equations for the averaged space have been derived with the procedure being valid on an arbitrary Riemannian space. The averaged space is characterized by a metric, Riemannian and non-Riemannian curvature 2-forms, and correlation 2-, 3- and 4-forms, an affine deformation 1-form being due to the non-metricity of one of two connection 1-forms. Using the procedure for the space-time averaging of the Einstein equations produces the averaged ones with the terms of geometric correction by the correlation tensors. The equations of motion for averaged energy momentum, obtained by averaging out the coritracted Bianchi identifies, also include such terms. Considering the gravitational induction tensor to be the Riemannian curvature tensor (the non-Riemannian one is then the field tensor), a theorem is proved which relates the algebraic structure of the averaged microscopic metric to that of the induction tensor. It is shown that the averaged Einstein equations can be put in the form of the Einstein equations with the conserved macroscopic energy-momentum tensor of a definite structure including the correlation functions. By using the high-frequency approximation of Isaacson with second-order correction to the microscopic metric, the self-consistency and compatibility of the equations and relations obtained are shown. Macrovacuum turns out to be Ricci non-flat, the macrovacuum source being defined in terms of the correlation functions. In the high-frequency limit the equations are shown to become Isaacson's ones with the macrovacuum source becoming Isaacson's stress tensor for gravitational waves. 17 refs

  1. Kv1 channels and neural processing in vestibular calyx afferents

    Directory of Open Access Journals (Sweden)

    Frances L Meredith

    2015-06-01

    Full Text Available Potassium-selective ion channels are important for accurate transmission of signals from auditory and vestibular sensory end organs to their targets in the central nervous system. During different gravity conditions, astronauts experience altered input signals from the peripheral vestibular system resulting in sensorimotor dysfunction. Adaptation to altered sensory input occurs, but it is not explicitly known whether this involves synaptic modifications within the vestibular epithelia. Future investigations of such potential plasticity require a better understanding of the electrophysiological mechanisms underlying the known heterogeneity of afferent discharge under normal conditions. This study advances this understanding by examining the role of the Kv1 potassium channel family in mediating action potentials in specialized vestibular afferent calyx endings in the gerbil crista and utricle. Pharmacological agents selective for different sub-types of Kv1 channels were tested on membrane responses in whole cell recordings in the crista. Kv1 channels sensitive to α-dendrotoxin and dendrotoxin-K were found to prevail in the central regions, whereas K+ channels sensitive to margatoxin, which blocks Kv1.3 and 1.6 channels, were more prominent in peripheral regions. Margatoxin-sensitive currents showed voltage-dependent inactivation. Dendrotoxin-sensitive currents showed no inactivation and dampened excitability in calyces in central neuroepithelial regions. The differential distribution of Kv1 potassium channels in vestibular afferents supports their importance in accurately relaying gravitational and head movement signals through specialized lines to the central nervous system. Pharmacological modulation of specific groups of K+ channels could help alleviate vestibular dysfunction on earth and in space.

  2. Kv1 channels and neural processing in vestibular calyx afferents.

    Science.gov (United States)

    Meredith, Frances L; Kirk, Matthew E; Rennie, Katherine J

    2015-01-01

    Potassium-selective ion channels are important for accurate transmission of signals from auditory and vestibular sensory end organs to their targets in the central nervous system. During different gravity conditions, astronauts experience altered input signals from the peripheral vestibular system resulting in sensorimotor dysfunction. Adaptation to altered sensory input occurs, but it is not explicitly known whether this involves synaptic modifications within the vestibular epithelia. Future investigations of such potential plasticity require a better understanding of the electrophysiological mechanisms underlying the known heterogeneity of afferent discharge under normal conditions. This study advances this understanding by examining the role of the Kv1 potassium channel family in mediating action potentials in specialized vestibular afferent calyx endings in the gerbil crista and utricle. Pharmacological agents selective for different sub-types of Kv1 channels were tested on membrane responses in whole cell recordings in the crista. Kv1 channels sensitive to α-dendrotoxin and dendrotoxin-K were found to prevail in the central regions, whereas K(+) channels sensitive to margatoxin, which blocks Kv1.3 and 1.6 channels, were more prominent in peripheral regions. Margatoxin-sensitive currents showed voltage-dependent inactivation. Dendrotoxin-sensitive currents showed no inactivation and dampened excitability in calyces in central neuroepithelial regions. The differential distribution of Kv1 potassium channels in vestibular afferents supports their importance in accurately relaying gravitational and head movement signals through specialized lines to the central nervous system. Pharmacological modulation of specific groups of K(+) channels could help alleviate vestibular dysfunction on earth and in space.

  3. Thermal activation and macroscopic quantum tunneling in a DC SQUID

    International Nuclear Information System (INIS)

    Sharifi, F.; Gavilano, J.L.; VanHarlingen, D.J.

    1989-01-01

    The authors report measurements of the transition rate from metastable minima in the two-dimensional 1 of a dc SQUID as a function of applied flux temperature. The authors observe a crossover from energy-activated escape to macroscopic quantum tunneling at a critical temperature. The macroscopic quantum tunneling rate is substantially reduced by damping, and also broadens the crossover region. Most interestingly, the authors observe thermal rates that are suppressed from those predicted by the two-dimensional thermal activation model. The authors discuss possible explanations for this based on the interaction of the macroscopic degree of freedom in the device and energy level effects

  4. Survey of magnetic fields near BPA 230-kV and 500-kV transmission lines

    International Nuclear Information System (INIS)

    Perrin, N.; Aggarwal, R.P.

    1991-01-01

    The purpose of this study was to characterize typical levels and variability of 60Hz magnetic fields at the centerline and edge of right-of-way of Bonneville Power Administration (BPA) 230-kV and 500-kV transmission lines. This was accomplished by taking magnetic field measurements at over 800 spans in Oregon and Washington. The spans were sampled using a stratified random sampling procedure with region (East vs. West), voltage (230-kV vs 500-kV), and circuit configuration as strata. There were five different circuit configuration groups for each region/voltage category requiring a total of 200 strata. Magnetic field measurements were taken at 13 locations under each span using an EMDEX-C as a survey meter. Additional information recorded for each span included conductor height (at 10 locations), right-of-way width, longitudinal and lateral slope, time of day, vegetation, terrain, weather conditions, temperature, wind speed, span length and presence of other lines in the corridor. 9 refs., 17 figs., 26 tabs

  5. KCNE4 is an inhibitory subunit to Kv1.1 and Kv1.3 potassium channels

    DEFF Research Database (Denmark)

    Grunnet, Morten; Rasmussen, Hannne B; Hay-Schmidt, Anders

    2003-01-01

    is detected in the heart and in five different parts of the brain. Having the broad distribution of Kv1 channels in mind, the demonstrated inhibitory property of KCNE4-subunits could locally and/or transiently have a dramatic influence on cellular excitability and on setting resting membrane potentials....

  6. Measurement-Induced Macroscopic Superposition States in Cavity Optomechanics

    DEFF Research Database (Denmark)

    Hoff, Ulrich Busk; Kollath-Bönig, Johann; Neergaard-Nielsen, Jonas Schou

    2016-01-01

    A novel protocol for generating quantum superpositions of macroscopically distinct states of a bulk mechanical oscillator is proposed, compatible with existing optomechanical devices operating in the bad-cavity limit. By combining a pulsed optomechanical quantum nondemolition (QND) interaction...

  7. Thermodynamical properties and thermoelastic coupling of complex macroscopic structure

    International Nuclear Information System (INIS)

    Fabbri, M.; Sacripanti, A.

    1996-11-01

    Gross qualitative/quantitative analysis about thermodynamical properties and thermoelastic coupling (or elastocaloric effect) of complex macroscopic structure (running shoes) is performed by infrared camera. The experimental results showed the achievability of a n industrial research project

  8. Single-Phase Bundle Flows Including Macroscopic Turbulence Model

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Jun; Yoon, Han Young [KAERI, Daejeon (Korea, Republic of); Yoon, Seok Jong; Cho, Hyoung Kyu [Seoul National University, Seoul (Korea, Republic of)

    2016-05-15

    To deal with various thermal hydraulic phenomena due to rapid change of fluid properties when an accident happens, securing mechanistic approaches as much as possible may reduce the uncertainty arising from improper applications of the experimental models. In this study, the turbulence mixing model, which is well defined in the subchannel analysis code such as VIPRE, COBRA, and MATRA by experiments, is replaced by a macroscopic k-e turbulence model, which represents the aspect of mathematical derivation. The performance of CUPID with macroscopic turbulence model is validated against several bundle experiments: CNEN 4x4 and PNL 7x7 rod bundle tests. In this study, the macroscopic k-e model has been validated for the application to subchannel analysis. It has been implemented in the CUPID code and validated against CNEN 4x4 and PNL 7x7 rod bundle tests. The results showed that the macroscopic k-e turbulence model can estimate the experiments properly.

  9. Dynamical fusion thresholds in macroscopic and microscopic theories

    International Nuclear Information System (INIS)

    Davies, K.T.R.; Sierk, A.J.; Nix, J.R.

    1983-01-01

    Macroscopic and microscopic results demonstrating the existence of dynamical fusion thresholds are presented. For macroscopic theories, it is shown that the extra-push dynamics is sensitive to some details of the models used, e.g. the shape parametrization and the type of viscosity. The dependence of the effect upon the charge and angular momentum of the system is also studied. Calculated macroscopic results for mass-symmetric systems are compared to experimental mass-asymmetric results by use of a tentative scaling procedure, which takes into account both the entrance-channel and the saddle-point regions of configuration space. Two types of dynamical fusion thresholds occur in TDHF studies: (1) the microscopic analogue of the macroscopic extra push threshold, and (2) the relatively high energy at which the TDHF angular momentum window opens. Both of these microscopic thresholds are found to be very sensitive to the choice of the effective two-body interaction

  10. Micro- and macroscopic photonic control of matter

    Science.gov (United States)

    Ryabtsev, Anton

    parameters. In order for measurements not to be skewed, these interactions need to be taken into account and mitigated at the time of the experiment or handled later in data analysis and simulations. Experimental results are presented in four chapters. Chapter 2 describes two topics: (1) single-shot real-time monitoring and correction of spectral phase drifts, which commonly originate from temperature and pointing fluctuations inside the laser cavity when the pulses are generated; (2) an all-optical method for controlling the dispersion of femtosecond pulses using other pulses. Chapter 3 focuses on the effects of the propagation media--how intense laser pulses modify media and how, in turn, the media modifies them back--and how these effects can be counteracted. Self-action effects in fused silica are discussed, along with some interesting and unexpected results. A method is then proposed for mitigating self-action processes using binary modulation of the spectral phases of laser pulses. Chapter 4 outlines the design of two laser systems, which are specifically tailored for particular spectroscopic applications and incorporate the comprehensive pulse control described in previous chapters. Chapter 5 shows how control of spatial beam characteristics can be applied to measurements of the mechanical motion of microscale particles and how it can potentially be applied to molecular motion. It also describes an experiment on laser-induced flow in air in which attempts were made to control the macroscopic molecular rotation of gases. My research, with a pulse shaper as the enabling tool, provides important insights into ultrafast scientific studies by making femtosecond laser research more predictable, reliable and practical for measurement and control. In the long term, some of the research methods in this thesis may help the transition of femtosecond lasers from the laboratory environment into clinics, factories, airports, and other everyday settings.

  11. 35-kV GaAs subnanosecond photoconductive switches

    Energy Technology Data Exchange (ETDEWEB)

    Pocha, M.D.; Druce, R.L. (Lawrence Livermore National Lab., CA (United States))

    1990-12-01

    Photoconductive switches are one of the few devices that allow the generation of high-voltage electrical pulses with subnanosecond rise time. The authors are exploring high-voltage, fast-pulse generation using GaAs photoconductive switches. They have been able to generate 35-kV pulses with rise times as short as 135 ps using 5-mm gap switches and have achieved electric field hold-off of greater than 100 kV/cm. They have also been able to generate an approximately 500-ps FWHM on/off electrical pulse with an amplitude of approximately 3 kV using neutron-irradiated GaAs having short carrier life times. This paper describes the experimental results and discusses fabrication of switches and the diagnostics used to measure these fast signals. They also describe the experience with the nonlinear lock-on and avalanche modes of operation observed in GaAs.

  12. 35-kV GaAs subnanosecond photoconductive switches

    Science.gov (United States)

    Pocha, Michael D.; Druce, Robert L.

    1990-12-01

    High-voltage, fast-pulse generation using GaAs photoconductive switches is investigated. It is possible to to generate 35-kV pulses with risetimes as short as 135 ps using 5-mm gap switches, and electric field hold-off of greater than 100 kV/cm is achieved. An approximately 500-ps FWHM on/off electrical pulse is generated with an amplitude of approximately 3 kV using neutron-irradiated GaAs having short carrier lifetimes. Experimental results are described, and fabrication of switches and the diagnostics used to measure these fast signals are discussed. Experience with the nonlinear lock-on and avalanche modes of operation observed in GaAs is also described.

  13. CIAE 600 kV ns pulse neutron generator

    International Nuclear Information System (INIS)

    Shen Guanren; Guan Xialing; Chen Hongtao

    2001-01-01

    The overall composition of CIAE 600 kV ns Pulse Neutron Generator (CPNG) are introduced, and its characteristic, main technological performance and application were also given. CPNG consists of high voltage power supply with highest output voltage 600 kV, direct current 15 mA, stability and ripple ≤0.1%, 2214 mm x 1604 mm x 1504 mm stainless steel high voltage electrode, built in head equipment uniform field accelerating tube, ns pulsed installation, turbomolecular vacuum pump system and drift pipes at 0 degree and 45 degree. Its characteristics are: (1) high current beam; (2) high current beam ns pulsed installation made use of low energy for chopper and high energy for buncher; (3) compactly laid out and simple in structure

  14. CEBAF 200 kV Inverted Electron Gun

    International Nuclear Information System (INIS)

    Grames, J.M.; Adderley, P.A.; Clark, J.; Hansknecht, J.; Poelker, M.; Stutzman, M.L.; Suleiman, R.; Surles-Law, K.E.L.

    2011-01-01

    Two DC high voltage GaAs photoguns have been built at Jefferson Lab based on a compact inverted insulator design. One photogun provides the polarized electron beam at CEBAF and operates at 130 kV bias voltage. The other gun is used for high average current lifetime studies at a dedicated test facility and has been operated at bias voltage up to 225 kV. The advantages of higher DC voltage for CEBAF include reduced space-charge emittance growth and the potential for prolonged photocathode lifetime. However, a consequence of operating at higher voltages is the increased likelihood of field emission or breakdown, both of which are unacceptable. Highlights of the R and D studies leading toward a production 200keV GaAs photogun for CEBAF will be presented.

  15. A compact 100 kV high voltage glycol capacitor.

    Science.gov (United States)

    Wang, Langning; Liu, Jinliang; Feng, Jiahuai

    2015-01-01

    A high voltage capacitor is described in this paper. The capacitor uses glycerol as energy storage medium, has a large capacitance close to 1 nF, can hold off voltages of up to 100 kV for μs charging time. Allowing for low inductance, the capacitor electrode is designed as coaxial structure, which is different from the common structure of the ceramic capacitor. With a steady capacitance at different frequencies and a high hold-off voltage of up to 100 kV, the glycol capacitor design provides a potential substitute for the ceramic capacitors in pulse-forming network modulator to generate high voltage pulses with a width longer than 100 ns.

  16. Bladder contractility is modulated by Kv7 channels in pig detrusor

    DEFF Research Database (Denmark)

    Svalø, Julie; Bille, Michala; Parameswaran Theepakaran, Neeraja

    2013-01-01

    Kv7 channels are involved in smooth muscle relaxation, and accordingly we believe that they constitute potential targets for the treatment of overactive bladder syndrome. We have therefore used myography to examine the function of Kv7 channels in detrusor, i.e. pig bladder, with a view...... relaxation, suggesting that Kv7.2 and/or Kv7.4 channels constitute the subtypes that are relevant to bladder contractility. The effects of retigabine and ML213 were attenuated by pre-incubation with 10µM XE991 (Kv7.1-7.5 channel blocker) (P...

  17. CONTRIBUTIONS OF INTRACELLULAR IONS TO Kv CHANNEL VOLTAGE SENSOR DYNAMICS.

    Directory of Open Access Journals (Sweden)

    Samuel eGoodchild

    2012-06-01

    Full Text Available Voltage sensing domains of Kv channels control ionic conductance through coupling of the movement of charged residues in the S4 segment to conformational changes at the cytoplasmic region of the pore domain, that allow K+ ions to flow. Conformational transitions within the voltage sensing domain caused by changes in the applied voltage across the membrane field are coupled to the conducting pore region and the gating of ionic conductance. However, several other factors not directly linked to the voltage dependent movement of charged residues within the voltage sensor impact the dynamics of the voltage sensor, such as inactivation, ionic conductance, intracellular ion identity and block of the channel by intracellular ligands. The effect of intracellular ions on voltage sensor dynamics is of importance in the interpretation of gating current measurements and the physiology of pore/voltage sensor coupling. There is a significant amount of variability in the reported kinetics of voltage sensor deactivation kinetics of Kv channels attributed to different mechanisms such as open state stabilization, immobilization and relaxation processes of the voltage sensor. Here we separate these factors and focus on the causal role that intracellular ions can play in allosterically modulating the dynamics of Kv voltage sensor deactivation kinetics. These considerations are of critical importance in understanding the molecular determinants of the complete channel gating cycle from activation to deactivation.

  18. The importance of immunohistochemical analyses in evaluating the phenotype of Kv channel knockout mice.

    Science.gov (United States)

    Menegola, Milena; Clark, Eliana; Trimmer, James S

    2012-06-01

    To gain insights into the phenotype of voltage-gated potassium (Kv)1.1 and Kv4.2 knockout mice, we used immunohistochemistry to analyze the expression of component principal or α subunits and auxiliary subunits of neuronal Kv channels in knockout mouse brains. Genetic ablation of the Kv1.1 α subunit did not result in compensatory changes in the expression levels or subcellular distribution of related ion channel subunits in hippocampal medial perforant path and mossy fiber nerve terminals, where high levels of Kv1.1 are normally expressed. Genetic ablation of the Kv4.2 α subunit did not result in altered neuronal cytoarchitecture of the hippocampus. Although Kv4.2 knockout mice did not exhibit compensatory changes in the expression levels or subcellular distribution of the related Kv4.3 α subunit, we found dramatic decreases in the cellular and subcellular expression of specific Kv channel interacting proteins (KChIPs) that reflected their degree of association and colocalization with Kv4.2 in wild-type mouse and rat brains. These studies highlight the insights that can be gained by performing detailed immunohistochemical analyses of Kv channel knockout mouse brains. Wiley Periodicals, Inc. © 2012 International League Against Epilepsy.

  19. Microscopic to macroscopic depletion model development for FORMOSA-P

    International Nuclear Information System (INIS)

    Noh, J.M.; Turinsky, P.J.; Sarsour, H.N.

    1996-01-01

    Microscopic depletion has been gaining popularity with regard to employment in reactor core nodal calculations, mainly attributed to the superiority of microscopic depletion in treating spectral history effects during depletion. Another trend is the employment of loading pattern optimization computer codes in support of reload core design. Use of such optimization codes has significantly reduced design efforts to optimize reload core loading patterns associated with increasingly complicated lattice designs. A microscopic depletion model has been developed for the FORMOSA-P pressurized water reactor (PWR) loading pattern optimization code. This was done for both fidelity improvements and to make FORMOSA-P compatible with microscopic-based nuclear design methods. Needless to say, microscopic depletion requires more computational effort compared with macroscopic depletion. This implies that microscopic depletion may be computationally restrictive if employed during the loading pattern optimization calculation because many loading patterns are examined during the course of an optimization search. Therefore, the microscopic depletion model developed here uses combined models of microscopic and macroscopic depletion. This is done by first performing microscopic depletions for a subset of possible loading patterns from which 'collapsed' macroscopic cross sections are obtained. The collapsed macroscopic cross sections inherently incorporate spectral history effects. Subsequently, the optimization calculations are done using the collapsed macroscopic cross sections. Using this approach allows maintenance of microscopic depletion level accuracy without substantial additional computing resources

  20. Extended Macroscopic Study of Dilute Gas Flow within a Microcavity

    Directory of Open Access Journals (Sweden)

    Mohamed Hssikou

    2016-01-01

    Full Text Available The behaviour of monatomic and dilute gas is studied in the slip and early transition regimes using the extended macroscopic theory. The gas is confined within a two-dimensional microcavity where the longitudinal sides are in the opposite motion with constant velocity ±Uw. The microcavity walls are kept at the uniform and reference temperature T0. Thus, the gas flow is transported only by the shear stress induced by the motion of upper and lower walls. From the macroscopic point of view, the regularized 13-moment equations of Grad, R13, are solved numerically. The macroscopic gas proprieties are studied for different values of the so-called Knudsen number (Kn, which gives the gas-rarefaction degree. The results are compared with those obtained using the classical continuum theory of Navier-Stokes and Fourier (NSF.

  1. Bell-inequality tests with macroscopic entangled states of light

    Energy Technology Data Exchange (ETDEWEB)

    Stobinska, M. [Max Planck Institute for the Science of Light, Erlangen (Germany); Institute for Theoretical Physics II, Erlangen-Nuernberg University, Erlangen (Germany); Sekatski, P.; Gisin, N. [Group of Applied Physics, University of Geneva, Geneva (Switzerland); Buraczewski, A. [Faculty of Electronics and Information Technology, Warsaw University of Technology, Warsaw (Poland); Leuchs, G. [Max Planck Institute for the Science of Light, Erlangen (Germany); Institute for Optics, Information and Photonics, Erlangen-Nuernberg University, Erlangen (Germany)

    2011-09-15

    Quantum correlations may violate the Bell inequalities. Most experimental schemes confirming this prediction have been realized in all-optical Bell tests suffering from the detection loophole. Experiments which simultaneously close this loophole and the locality loophole are highly desirable and remain challenging. An approach to loophole-free Bell tests is based on amplification of the entangled photons (i.e., on macroscopic entanglement), for which an optical signal should be easy to detect. However, the macroscopic states are partially indistinguishable by classical detectors. An interesting idea to overcome these limitations is to replace the postselection by an appropriate preselection immediately after the amplification. This is in the spirit of state preprocessing revealing hidden nonlocality. Here, we examine one of the possible preselections, but the presented tools can be used for analysis of other schemes. Filtering methods making the macroscopic entanglement useful for Bell tests and quantum protocols are the subject of an intensive study in the field nowadays.

  2. Decoherence bypass of macroscopic superpositions in quantum measurement

    International Nuclear Information System (INIS)

    Spehner, Dominique; Haake, Fritz

    2008-01-01

    We study a class of quantum measurement models. A microscopic object is entangled with a macroscopic pointer such that a distinct pointer position is tied to each eigenvalue of the measured object observable. Those different pointer positions mutually decohere under the influence of an environment. Overcoming limitations of previous approaches we (i) cope with initial correlations between pointer and environment by considering them initially in a metastable local thermal equilibrium, (ii) allow for object-pointer entanglement and environment-induced decoherence of distinct pointer readouts to proceed simultaneously, such that mixtures of macroscopically distinct object-pointer product states arise without intervening macroscopic superpositions, and (iii) go beyond the Markovian treatment of decoherence. (fast track communication)

  3. Rapid internalization of the oncogenic K+ channel K(V10.1.

    Directory of Open Access Journals (Sweden)

    Tobias Kohl

    Full Text Available K(V10.1 is a mammalian brain voltage-gated potassium channel whose ectopic expression outside of the brain has been proven relevant for tumor biology. Promotion of cancer cell proliferation by K(V10.1 depends largely on ion flow, but some oncogenic properties remain in the absence of ion permeation. Additionally, K(V10.1 surface populations are small compared to large intracellular pools. Control of protein turnover within cells is key to both cellular plasticity and homeostasis, and therefore we set out to analyze how endocytic trafficking participates in controlling K(V10.1 intracellular distribution and life cycle. To follow plasma membrane K(V10.1 selectively, we generated a modified channel of displaying an extracellular affinity tag for surface labeling by α-bungarotoxin. This modification only minimally affected K(V10.1 electrophysiological properties. Using a combination of microscopy and biochemistry techniques, we show that K(V10.1 is constitutively internalized involving at least two distinct pathways of endocytosis and mainly sorted to lysosomes. This occurs at a relatively fast rate. Simultaneously, recycling seems to contribute to maintain basal K(V10.1 surface levels. Brief K(V10.1 surface half-life and rapid lysosomal targeting is a relevant factor to be taken into account for potential drug delivery and targeting strategies directed against K(V10.1 on tumor cells.

  4. Statistical thermodynamics understanding the properties of macroscopic systems

    CERN Document Server

    Fai, Lukong Cornelius

    2012-01-01

    Basic Principles of Statistical PhysicsMicroscopic and Macroscopic Description of StatesBasic PostulatesGibbs Ergodic AssumptionGibbsian EnsemblesExperimental Basis of Statistical MechanicsDefinition of Expectation ValuesErgodic Principle and Expectation ValuesProperties of Distribution FunctionRelative Fluctuation of an Additive Macroscopic ParameterLiouville TheoremGibbs Microcanonical EnsembleMicrocanonical Distribution in Quantum MechanicsDensity MatrixDensity Matrix in Energy RepresentationEntropyThermodynamic FunctionsTemperatureAdiabatic ProcessesPressureThermodynamic IdentityLaws of Th

  5. Plasmonic direct writing lithography with a macroscopical contact probe

    Science.gov (United States)

    Huang, Yuerong; Liu, Ling; Wang, Changtao; Chen, Weidong; Liu, Yunyue; Li, Ling

    2018-05-01

    In this work, we design a plasmonic direct writing lithography system with a macroscopical contact probe to achieve nanometer scale spots. The probe with bowtie-shaped aperture array adopts spring hinge and beam deflection method (BDM) to realize near-field lithography. Lithography results show that a macroscopical plasmonic contact probe can achieve a patterning resolution of around 75 nm at 365 nm wavelength, and demonstrate that the lithography system is promising for practical applications due to beyond the diffraction limit, low cost, and simplification of system configuration. CST calculations provide a guide for the design of recording structure and the arrangement of placing polarizer.

  6. Fluctuations in macroscopically agitated plasma:quasiparticles and effective temperature

    International Nuclear Information System (INIS)

    Sosenko, P.P.; Gresillon, D.

    1994-01-01

    Fluctuations in the plasma, in which macroscopic fluid-like motion is agitated due to large-scale and low-frequency electro-magnetic fields, are studied. Such fields can be produced by external factors or internally, for example due to turbulence. Fluctuation spectral distributions are calculated with regard to the renormalization of the transition probability for a test-particle and of the test-particle shielding. If the correlation length for the random fluid-like motion is large as compared to the fluctuation scale lengths, then the fluctuation spectral distributions can be explained in terms of quasiparticles originating from macroscopic plasma agitation and of an effective temperature

  7. Macroscopic and radiographic examination of proximal root surface caries

    International Nuclear Information System (INIS)

    Nordenram, G.; Bergvist, A.; Johnson, G.; Henriksen, C.O.; Anneroth, G.

    1988-01-01

    The purpose of the study was to compare macroscopic and radiographic examination of proximal root surface caries of extracted teeth from patients aged 65-95 years. Although the study conditions for macroscopic and radiographic diagnosis favored more sensitive evaluations than routine clinical conditions, there was a 24% disagreement in diagnosis. This finding indicates that under routine clinical conditions it is difficult to register with certainty all superficial root carious lesions. Even in the absence of clinically detectable root surface caries, preventive measures should be considered for elderly people with exposed root surfaces

  8. The transient outward current in mice lacking the potassium channel gene Kv1.4

    Science.gov (United States)

    London, Barry; Wang, Dao W; Hill, Joseph A; Bennett, Paul B

    1998-01-01

    The transient outward current (Ito) plays a prominent role in the repolarization phase of the cardiac action potential. Several K+ channel genes, including Kv1.4, are expressed in the heart, produce rapidly inactivating currents when heterologously expressed, and may be the molecular basis of Ito.We engineered mice homozygous for a targeted disruption of the K+ channel gene Kv1.4 and compared Ito in wild-type (Kv1.4+/+), heterozygous (Kv1.4+/-) and homozygous ‘knockout’ (Kv1.4−/−) mice. Kv1.4 RNA was truncated in Kv1.4−/− mice and protein expression was absent.Adult myocytes isolated from Kv1.4+/+, Kv1.4+/− and Kv1.4−/− mice had large rapidly inactivating outward currents. The peak current densities at 60 mV (normalized by cellular capacitance, in pA pF−1; means ± s.e.m.) were 53.8 ± 5.3, 45.3 ± 2.2 and 44.4 ± 2.8 in cells from Kv1.4+/+, Kv1.4+/− and Kv1.4−/− mice, respectively (P mice.The voltage dependence and time course of inactivation were not changed by targeted disruption of Kv1.4. The mean best-fitting V½ (membrane potential at 50 % inactivation) values for myocytes from Kv1.4 +/+, Kv1.4+/− and Kv1.4−/− mice were -53.5 ± 3.7, -51.1 ± 2.6 and -54.2 ± 2.4 mV, respectively. The slope factors (k) were -10.1 ± 1.4, -8.8 ± 1.4 and -9.5 ± 1.2 mV, respectively. The fast time constants for development of inactivation at -30 mV were 27.8 ± 2.2, 26.2 ± 5.1 and 19.6 ± 2.1 ms in Kv1.4+/+, Kv1.4+/− and Kv1.4−/− myocytes, respectively. At +30 mV, they were 35.5 ± 2.6, 30.0 ± 2.1 and 28.7 ± 1.6 ms, respectively. The time constants for the rapid phase of recovery from inactivation at -80 mV were 32.5 ± 8.2, 23.3 ± 1.8 and 39.0 ± 3.7 ms, respectively.Nearly the entire inactivating component as well as more than 60 % of the steady-state outward current was eliminated by 1 mm 4-aminopyridine in Kv1.4+/+, Kv1.4+/− and Kv1.4−/− myocytes.Western blot analysis of heart membrane extracts showed no significant

  9. 735 kV circuit breakers for ehv

    Energy Technology Data Exchange (ETDEWEB)

    1966-01-01

    French manufacturers have been studying the design of high and extra high voltage circuit breakers for several years. The two techniques they used were the low volume oil and the air pressure technique. These have permitted the development of a type gear capable of solving problems all over the world as they arose following the development of electrical energy transmission at extra high voltage as well as high short circuit power. Today, the air pressure solution is used in new constructions such as the 735 kV transmission network in Canada.

  10. Design and testing of reactors for 735 kV

    Energy Technology Data Exchange (ETDEWEB)

    Erb, W; Kraaij, D J

    1965-11-01

    The design and testing of five large, single phase shunt reactors rated either 110 or 55 MVAR, supplied for the 735 kV system of the Quebec Hydro Electric Commission which came into operation in the autumn of 1965 are described. As these reactors are permanently connected to the transmission lines, their losses must be considered as being continuously present and must be determined exactly. In addition to the use of a new bridge method, the losses were also measured calorimetrically for the purpose of comparison, the agreement between the two tests being remarkably good. The impulse tests with full wave and chopped wave are subsequently described.

  11. Vascular flora and macroscopic fauna on the Fernow Experimental Forest

    Science.gov (United States)

    Darlene M. Madarish; Jane L. Rodrigue; Mary Beth Adams

    2002-01-01

    This report is the first comprehensive inventory of the vascular flora and macroscopic fauna known to occur within the Fernow Experimental Forest in north-central West Virignia. The compendium is based on information obtained from previous surveys, current research, and the personal observations of USDA Forest Service personnel and independent scientists. More than 750...

  12. On the problem of contextuality in macroscopic magnetization measurements

    International Nuclear Information System (INIS)

    Soeda, Akihito; Kurzyński, Paweł; Ramanathan, Ravishankar; Grudka, Andrzej; Thompson, Jayne; Kaszlikowski, Dagomir

    2013-01-01

    We show that sharp measurements of total magnetization cannot be used to reveal contextuality in macroscopic many-body systems of spins of arbitrary dimension. We decompose each such measurement into set of projectors corresponding to well-defined value of total magnetization. We then show that such sets of projectors are too restricted to construct Kochen–Specker sets.

  13. Photoinduced macroscopic chiral structures in a series of azobenzene copolyesters

    DEFF Research Database (Denmark)

    Nedelchev, L.; Nikolova, L.; Matharu, A.

    2002-01-01

    A study of the propagation of elliptically polarized light and the resulting formation of macroscopic chiral structures in a series of azobenzene side-chain copolyesters, in which the morphology is varied from liquid crystalline to amorphous, is reported. Real-time measurements are presented...

  14. Modification of the Charlesby law. Pt. 2. Macroscopic sensitivity

    International Nuclear Information System (INIS)

    Schiltz, A.; Weil, A.; Paniez, P.

    1984-01-01

    In part II, results are presented showing that for doses below macroscopic sensitivity, Qsub(sm), degradation due to fluence of the particles seems to be non-uniform over the entire area. In the light of this, a modification of the Charlesby's law is proposed providing a solution to the problems considered in part I [fr

  15. Charge of a macroscopic particle in a plasma sheath

    International Nuclear Information System (INIS)

    Samarian, A.A.; Vladimirov, S.V.

    2003-01-01

    Charging of a macroscopic body levitating in a rf plasma sheath is studied experimentally and theoretically. The nonlinear charge vs size dependence is obtained. The observed nonlinearity is explained on the basis of an approach taking into account different plasma conditions for the levitation positions of different particles. The importance of suprathermal electrons' contribution to the charging process is demonstrated

  16. Macroscopic Fundamental Diagram for pedestrian networks : Theory and applications

    NARCIS (Netherlands)

    Hoogendoorn, S.P.; Daamen, W.; Knoop, V.L.; Steenbakkers, Jeroen; Sarvi, Majid

    2017-01-01

    The Macroscopic Fundamental diagram (MFD) has proven to be a powerful concept in understanding and managing vehicular network dynamics, both from a theoretical angle and from a more application-oriented perspective. In this contribution, we explore the existence and the characteristics of the

  17. Emergence of an urban traffic macroscopic fundamental diagram

    DEFF Research Database (Denmark)

    Ranjan, Abhishek; Fosgerau, Mogens; Jenelius, Erik

    2016-01-01

    This paper examines mild conditions under which a macroscopic fundamental diagram (MFD) emerges, relating space-averaged speed to occupancy in some area. These conditions are validated against empirical data. We allow local speedoccupancy relationships and, in particular, require no equilibrating...

  18. Stereodynamics: From elementary processes to macroscopic chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Toshio [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Graduate School of Science, Department of Chemistry, Osaka University, Toyonaka, 560-0043 Osaka (Japan); Che, Dock-Chil [Graduate School of Science, Department of Chemistry, Osaka University, Toyonaka, 560-0043 Osaka (Japan); Tsai, Po-Yu [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Lin, King-Chuen [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Palazzetti, Federico [Scuola Normale Superiore, Pisa (Italy); Dipartimento di Chimica Biologia e Biotecnologie, Università di Perugia, 06123 Perugia (Italy); Aquilanti, Vincenzo [Dipartimento di Chimica Biologia e Biotecnologie, Università di Perugia, 06123 Perugia (Italy); Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Roma (Italy); Instituto de Fisica, Universidade Federal da Bahia, Salvador (Brazil)

    2015-12-31

    This paper aims at discussing new facets on stereodynamical behaviors in chemical reactions, i.e. the effects of molecular orientation and alignment on reactive processes. Further topics on macroscopic processes involving deviations from Arrhenius behavior in the temperature dependence of chemical reactions and chirality effects in collisions are also discussed.

  19. Macroscopic realism and quantum measurement: measurers as a natural kind

    International Nuclear Information System (INIS)

    Jaeger, Gregg

    2014-01-01

    The notion of macroscopic realism has been used in attempts to achieve consistency between physics and everyday experience and to locate some boundary between the realms of classical mechanics and quantum meachanics. Its ostensibly underlying conceptual components, realism and macroscopicity, have most often appeared in the foundations of physics in relation to quantum measurement: reality became a prominent topic of discussion in quantum physics after the notion of element of reality was defined and used by Einstein, Podolsky and Rosen in that context, and macroscopicity is often explicitly assumed to be an essential property of any measuring apparatus. However, macroscopicity turns out to be a rather vaguer and less consistently understood notion than typically assumed by physicists who have not explicitly explored the notion themselves. For this reason, it behooves those investigating the foundations of quantum mechanics from a realist perspective to look for alternative notions for grounding quantum measurement. Here, the merits of treating the measuring instrument as a ‘natural kind’ as a means of avoiding anthropocentrism in the foundations of quantum measurement are pointed out as a means of advancing quantum measurement theory. (paper)

  20. Microstructure and macroscopic properties of polydisperse systems of hard spheres

    NARCIS (Netherlands)

    Ogarko, V.

    2014-01-01

    This dissertation describes an investigation of systems of polydisperse smooth hard spheres. This includes the development of a fast contact detection algorithm for computer modelling, the development of macroscopic constitutive laws that are based on microscopic features such as the moments of the

  1. Macroscopic domain formation in the platelet plasma membrane

    DEFF Research Database (Denmark)

    Bali, Rachna; Savino, Laura; Ramirez, Diego A.

    2009-01-01

    There has been ample debate on whether cell membranes can present macroscopic lipid domains as predicted by three-component phase diagrams obtained by fluorescence microscopy. Several groups have argued that membrane proteins and interactions with the cytoskeleton inhibit the formation of large d...

  2. Macroscopic charge quantization in single-electron devices

    NARCIS (Netherlands)

    Burmistrov, I.S.; Pruisken, A.M.M.

    2010-01-01

    In a recent paper by the authors [I. S. Burmistrov and A. M. M. Pruisken, Phys. Rev. Lett. 101, 056801 (2008)] it was shown that single-electron devices (single-electron transistor or SET) display "macroscopic charge quantization" which is completely analogous to the quantum Hall effect observed on

  3. Macroscopic and microscopic magnetism of metal-metalloid amorphous alloys

    International Nuclear Information System (INIS)

    Vasconcellos, M.A.Z.; Fichtner, P.F.P.; Livi, F.P.; Costa, M.I. da; Baibich, M.N.

    1984-01-01

    In this paper is investigated the interrelation between macroscopic and microscopic magnetic phenomena using experimetnal data from Moessbauer effect and the magnetization of layers of amorphous (Fe 1-x Ni x ) 80 B 20 . The Moessbauer effect measurement show a distribution of hyperfine fields in Fe site as well as a likely distribution of isomeric shifts (M.W.O.) [pt

  4. The C-terminal HRET sequence of Kv1.3 regulates gating rather than targeting of Kv1.3 to the plasma membrane.

    Science.gov (United States)

    Voros, Orsolya; Szilagyi, Orsolya; Balajthy, András; Somodi, Sándor; Panyi, Gyorgy; Hajdu, Péter

    2018-04-12

    Kv1.3 channels are expressed in several cell types including immune cells, such as T lymphocytes. The targeting of Kv1.3 to the plasma membrane is essential for T cell clonal expansion and assumed to be guided by the C-terminus of the channel. Using two point mutants of Kv1.3 with remarkably different features compared to the wild-type Kv1.3 (A413V and H399K having fast inactivation kinetics and tetraethylammonium-insensitivity, respectively) we showed that both Kv1.3 channel variants target to the membrane when the C-terminus was truncated right after the conserved HRET sequence and produce currents identical to those with a full-length C-terminus. The truncation before the HRET sequence (NOHRET channels) resulted in reduced membrane-targeting but non-functional phenotypes. NOHRET channels did not display gating currents, and coexpression with wild-type Kv1.3 did not rescue the NOHRET-A413V phenotype, no heteromeric current was observed. Interestingly, mutants of wild-type Kv1.3 lacking HRET(E) (deletion) or substituted with five alanines for the HRET(E) motif expressed current indistinguishable from the wild-type. These results demonstrate that the C-terminal region of Kv1.3 immediately proximal to the S6 helix is required for the activation gating and conduction, whereas the presence of the distal region of the C-terminus is not exclusively required for trafficking of Kv1.3 to the plasma membrane.

  5. Wild Horse 69-kV transmission line environmental assessment

    International Nuclear Information System (INIS)

    1996-12-01

    Hill County Electric Cooperative Inc. (Hill County) proposes to construct and operate a 69-kV transmission line from its North Gildford Substation in Montana north to the Canadian border. A vicinity project area map is enclosed as a figure. TransCanada Power Corporation (TCP), a Canadian power-marketing company, will own and construct the connecting 69-kV line from the international border to Express Pipeline's pump station at Wild Horse, Alberta. This Environmental Assessment is prepared for the Department of Energy (DOE) as lead federal agency to comply with the requirements of the National Environmental Policy Act (NEPA), as part of DOE's review and approval process of the applications filed by Hill County for a DOE Presidential Permit and License to Export Electricity to a foreign country. The purpose of the proposed line is to supply electric energy to a crude oil pump station in Canada, owned by Express Pipeline Ltd. (Express). The pipeline would transport Canadian-produced oil from Hardisty, Alberta, Canada, to Caster, Wyoming. The Express Pipeline is scheduled to be constructed in 1996--97 and will supply crude oil to refineries in Wyoming and the midwest

  6. Corona performance of a compact 230-kV line

    International Nuclear Information System (INIS)

    Chartier, V.L.; Blair, D.E.

    1994-01-01

    Permitting requirements and the acquisition of new rights-of-way for transmission facilities has in recent years become increasingly difficult for most utilities, including Puget Sound Power and Light Company. In order to maintain a high degree of reliability of service while being responsive to public concerns regarding the siting of high voltage (HV) transmission facilities, Puget Power has found it necessary to more heavily rely upon the use of compact lines in franchise corridors. Compaction does, however, precipitant increased levels of audible noise (AN) and radio and TV interference (RI and TVI) due to corona on the conductors and insulator assemblies. Puget Power relies upon the Bonneville Power Administration (BPA) Corona and Field Effects computer program to calculate AN and RI for new lines. Since there was some question of the program's ability to accurately represent quiet 230-kV compact designs, a joint project was undertaken with BPA to verify the program's algorithms. Long-term measurements made on an operating Puget Power 230-kV compact line confirmed the accuracy of BPA's AN model; however, the RI measurements were much lower than predicted by the BPA computer and other programs. This paper also describes how the BPA computer program can be used to calculate the voltage needed to expose insulator assemblies to the correct electric field in single test setups in HV laboratories

  7. A continuous acceleration tube of ions under 200 KV

    International Nuclear Information System (INIS)

    Mongodin, G.

    1954-01-01

    The realization of an Van de Graaff accelerator required, for the preliminary studies, the construction of a small proton accelerator, functioning at 200 kV in order to resolve some parasitic effects inherent to the accelerators tubes. The aim of this report is to describe the different organs of the accelerator tube, to explain the operating system and to encode their characteristics. The report first presents the ion source and the beam buncher permitting to inject in the accelerator tube particles of about 9 kV and very batched in a thin beam of circular section. Then the study explain the tube characteristics considered like optic system. A method to obtain precise calculation of particle trajectories is exposed. Aberrations of the system were discussed and balance of the currents on all electrodes inside the tube for different regimes of working were provided. The influence of the residual pressure in the tube were explained. The report finally ends on a part of the fundamental problem of the straining occurring inside the tubes accelerators under high tension. (M.B.) [fr

  8. Wild Horse 69-kV transmission line environmental assessment

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

    Hill County Electric Cooperative Inc. (Hill County) proposes to construct and operate a 69-kV transmission line from its North Gildford Substation in Montana north to the Canadian border. A vicinity project area map is enclosed as a figure. TransCanada Power Corporation (TCP), a Canadian power-marketing company, will own and construct the connecting 69-kV line from the international border to Express Pipeline`s pump station at Wild Horse, Alberta. This Environmental Assessment is prepared for the Department of Energy (DOE) as lead federal agency to comply with the requirements of the National Environmental Policy Act (NEPA), as part of DOE`s review and approval process of the applications filed by Hill County for a DOE Presidential Permit and License to Export Electricity to a foreign country. The purpose of the proposed line is to supply electric energy to a crude oil pump station in Canada, owned by Express Pipeline Ltd. (Express). The pipeline would transport Canadian-produced oil from Hardisty, Alberta, Canada, to Caster, Wyoming. The Express Pipeline is scheduled to be constructed in 1996--97 and will supply crude oil to refineries in Wyoming and the midwest.

  9. Expression and function of K(V)2-containing channels in human urinary bladder smooth muscle.

    Science.gov (United States)

    Hristov, Kiril L; Chen, Muyan; Afeli, Serge A Y; Cheng, Qiuping; Rovner, Eric S; Petkov, Georgi V

    2012-06-01

    The functional role of the voltage-gated K(+) (K(V)) channels in human detrusor smooth muscle (DSM) is largely unexplored. Here, we provide molecular, electrophysiological, and functional evidence for the expression of K(V)2.1, K(V)2.2, and the electrically silent K(V)9.3 subunits in human DSM. Stromatoxin-1 (ScTx1), a selective inhibitor of K(V)2.1, K(V)2.2, and K(V)4.2 homotetrameric channels and of K(V)2.1/9.3 heterotetrameric channels, was used to examine the role of these channels in human DSM function. Human DSM tissues were obtained during open bladder surgeries from patients without a history of overactive bladder. Freshly isolated human DSM cells were studied using RT-PCR, immunocytochemistry, live-cell Ca(2+) imaging, and the perforated whole cell patch-clamp technique. Isometric DSM tension recordings of human DSM isolated strips were conducted using tissue baths. RT-PCR experiments showed mRNA expression of K(V)2.1, K(V)2.2, and K(V)9.3 (but not K(V)4.2) channel subunits in human isolated DSM cells. K(V)2.1 and K(V)2.2 protein expression was confirmed by Western blot analysis and immunocytochemistry. Perforated whole cell patch-clamp experiments revealed that ScTx1 (100 nM) inhibited the amplitude of the voltage step-induced K(V) current in freshly isolated human DSM cells. ScTx1 (100 nM) significantly increased the intracellular Ca(2+) level in DSM cells. In human DSM isolated strips, ScTx1 (100 nM) increased the spontaneous phasic contraction amplitude and muscle force, and enhanced the amplitude of the electrical field stimulation-induced contractions within the range of 3.5-30 Hz stimulation frequencies. These findings reveal that ScTx1-sensitive K(V)2-containing channels are key regulators of human DSM excitability and contractility and may represent new targets for pharmacological or genetic intervention for bladder dysfunction.

  10. Macroscopic quantum phenomena from the large N perspective

    International Nuclear Information System (INIS)

    Chou, C H; Hu, B L; Subasi, Y

    2011-01-01

    Macroscopic quantum phenomena (MQP) is a relatively new research venue, with exciting ongoing experiments and bright prospects, yet with surprisingly little theoretical activity. What makes MQP intellectually stimulating is because it is counterpoised against the traditional view that macroscopic means classical. This simplistic and hitherto rarely challenged view need be scrutinized anew, perhaps with much of the conventional wisdoms repealed. In this series of papers we report on a systematic investigation into some key foundational issues of MQP, with the hope of constructing a viable theoretical framework for this new endeavour. The three major themes discussed in these three essays are the large N expansion, the correlation hierarchy and quantum entanglement for systems of 'large' sizes, with many components or degrees of freedom. In this paper we use different theories in a variety of contexts to examine the conditions or criteria whereby a macroscopic quantum system may take on classical attributes, and, more interestingly, that it keeps some of its quantum features. The theories we consider here are, the O(N) quantum mechanical model, semiclassical stochastic gravity and gauge / string theories; the contexts include that of a 'quantum roll' in inflationary cosmology, entropy generation in quantum Vlasov equation for plasmas, the leading order and next-to-leading order large N behaviour, and hydrodynamic / thermodynamic limits. The criteria for classicality in our consideration include the use of uncertainty relations, the correlation between classical canonical variables, randomization of quantum phase, environment-induced decoherence, decoherent history of hydrodynamic variables, etc. All this exercise is to ask only one simple question: Is it really so surprising that quantum features can appear in macroscopic objects? By examining different representative systems where detailed theoretical analysis has been carried out, we find that there is no a priori

  11. The origins of macroscopic quantum coherence in high temperature superconductivity

    International Nuclear Information System (INIS)

    Turner, Philip; Nottale, Laurent

    2015-01-01

    Highlights: • We propose a new theoretical approach to superconductivity in p-type cuprates. • Electron pairing mechanisms in the superconducting and pseudogap phases are proposed. • A scale free network of dopants is key to macroscopic quantum coherence. - Abstract: A new, theoretical approach to macroscopic quantum coherence and superconductivity in the p-type (hole doped) cuprates is proposed. The theory includes mechanisms to account for e-pair coupling in the superconducting and pseudogap phases and their inter relations observed in these materials. Electron pair coupling in the superconducting phase is facilitated by local quantum potentials created by static dopants in a mechanism which explains experimentally observed optimal doping levels and the associated peak in critical temperature. By contrast, evidence suggests that electrons contributing to the pseudogap are predominantly coupled by fractal spin waves (fractons) induced by the fractal arrangement of dopants. On another level, the theory offers new insights into the emergence of a macroscopic quantum potential generated by a fractal distribution of dopants. This, in turn, leads to the emergence of coherent, macroscopic spin waves and a second associated macroscopic quantum potential, possibly supported by charge order. These quantum potentials play two key roles. The first involves the transition of an expected diffusive process (normally associated with Anderson localization) in fractal networks, into e-pair coherence. The second involves the facilitation of tunnelling between localized e-pairs. These combined effects lead to the merger of the super conducting and pseudo gap phases into a single coherent condensate at optimal doping. The underlying theory relating to the diffusion to quantum transition is supported by Coherent Random Lasing, which can be explained using an analogous approach. As a final step, an experimental program is outlined to validate the theory and suggests a new

  12. Contribution of kv7.4/kv7.5 heteromers to intrinsic and calcitonin gene-related Peptide-induced cerebral reactivity

    DEFF Research Database (Denmark)

    Chadha, Preet S; Jepps, Thomas A; Carr, Georgina

    2014-01-01

    Middle cerebral artery (MCA) diameter is regulated by inherent myogenic activity and the effect of potent vasodilators such as calcitonin gene-related peptide (CGRP). Previous studies showed that MCAs express KCNQ1, 4, and 5 potassium channel genes, and the expression products (Kv7 channels) part......) participate in the myogenic control of MCA diameter. The present study investigated the contribution of Kv7.4 and Kv7.5 isoforms to myogenic and CGRP regulation of MCA diameter and determined whether they were affected in hypertensive animals....

  13. High power thyristors with 5 kV blocking voltage. Volume 1: Development of high-voltage-thyristors (4.5 kV) with good dynamic properties

    Science.gov (United States)

    Lock, K.; Patalong, H.; Platzoeder, K.

    1979-01-01

    Using neutron irradiated silicon with considerably lower spread in resistivity as compared to conventionally doped silicon it was possible to produce power thyristors with breakdown voltages between 3.5 kV and 5.5 kV. The thyristor pellets have a diameter of 50 mm. Maximum average on-state currents of 600 to 800 A can be reached with these elements. The dynamic properties of the thryistors could be improved to allow standard applications up to maximum repetitive voltages of 4.5 kV.

  14. The pan-Kv7 (KCNQ) Channel Opener Retigabine Inhibits Striatal Excitability by Direct Action on Striatal Neurons In Vivo

    DEFF Research Database (Denmark)

    Hansen, Henrik H; Weikop, Pia; Mikkelsen, Maria D

    2017-01-01

    Central Kv7 (KCNQ) channels are voltage-dependent potassium channels composed of different combinations of four Kv7 subunits, being differently expressed in the brain. Notably, striatal dopaminergic neurotransmission is strongly suppressed by systemic administration of the pan-Kv7 channel opener ...... by acute systemic haloperidol administration in the rat. The relative mRNA levels of Kv7 subunits in the rat striatum were found to be Kv7.2 = Kv7.3 = Kv7.5 > >Kv7.4. These data suggest that intrastriatal Kv7 channels play a direct role in regulating striatal excitability in vivo....

  15. 400 kV injector compact ECR ion source

    International Nuclear Information System (INIS)

    Constantin, F.; Catana, D.; Macovei, M.; Ivanov, E.

    1997-01-01

    Obtaining multiple ionised ions is a fundamental problem for some applications and research. Multiple ionised ions can be produced from electronic bombardment, when n·τ≥5·10 9 cm -3 · s, where n is the density of electrons (in cm -3 ) and τ is the time of interaction between electrons and ions . The relative speed of electrons and ions determines the equilibrium between the stripping process of the atom's electrons and their capture. An ion source with high ionisation efficiency and large output current is the ECR source (Electron Cyclotron Resonance). Using an ECR source with permanent magnets as ion source for the injector will lead to following advantages: - the possibility to obtain multiple ionised particles; - an increase of ion beam intensities; - the expanding of accelerator activities; - a longer working time, due to magnetron lifetime. The ECR ion source is robust, compact and capable of high intensities of extracted ion current. The large functional domain for the residual gas pressure allows the production of multiple charged ions. The source can be easily integrated in the TRILAC's injection structure. We realised a compact microwave ion source which has an axial magnetic field generated by a permanent magnet of Co-Sm. 1200 G magnetic field is greater than the 875 G magnetic field corresponding to the electron-cyclotron frequency of 2.45 GHz. The microwave generator is a magnetron (2.45 GHz and 200 W in continuos wave). The microwave is fed through a coaxial connector on the top of flange. The test was made on He gas at a pressure between 8· 10 -4 and 5·10 -2 torr. The ion beam current was measured vs. extracted potential from 3 kV to 10 kV and has a dependence according to U 3/2 law. A maximal ion current of 300 μA at 10 kV extraction potential was measured. Dimension of ECR ion source, including Einzel lens are φ=12 cm and h=16 cm. (authors)

  16. The short-circuit test results of 6.9 kV/2.3 kV 400 kVA-class YBCO model transformer

    International Nuclear Information System (INIS)

    Tomioka, A.; Otonari, T.; Ogata, T.; Iwakuma, M.; Okamoto, H.; Hayashi, H.; Iijima, Y.; Saito, T.; Gosho, Y.; Tanabe, K.; Izumi, T.; Shiohara, Y.

    2011-01-01

    The 6.9 kV/2.3 kV 400 kVA-class single-phase YBCO model transformer with the YBCO tape with copper tape was manufactured for short-circuit current test. Short-circuit test was performed and the short-circuit current of primary winding was 346 A which was about six times larger than the rated current. The I-V characteristics of the winding did not change before and after the test. The transformer withstood short-circuit current. We are planning to turn the result into a consideration of a 66 kV/6.9 kV-20 MVA-class three-phase superconducting transformer. We are developing an elemental technology for 66 kV/6.9 kV 20 MVA-class power transformer with YBCO conductors. The protection of short-circuit technology is one of the elemental technologies for HTS transformer. Since short-circuit current is much higher than critical current of YBCO tape, there is a possibility that superconducting characteristics may be damaged during short-circuit period. We made a conductor to compose the YBCO tape with copper tape. We manufactured 6.9 kV/2.3 kV 400 kVA-class YBCO model transformer using this conductor and performed short-circuit current test. The short-circuit current of primary winding was 346 A which was about six times larger than the rated current. The I-V characteristics of the winding did not change before and after the test. We may consider this conductor withstands short-circuit current.

  17. 100 kV reliable accurately-synchronized spark gap

    International Nuclear Information System (INIS)

    Bosamykin, V.S.; Gerasimov, A.I.; Zenkov, D.I.

    1987-01-01

    100 kV three-electrode spark gap filled with 40% SF 6 +60% N 2 mixture under the pressure of ∼ 1 MPa, which has spread Δt ≤ ± 5 ns of operating time delay in the range of 10 4 triggerings and commutation energy of 2.5 kJ, providing electric strength is 100%, is described; at 10 kJ Δt is less than ± 10 ns for 10 3 triggerings. Parallel connection of 16 groups, each consisting of 5 spark gaps with series connection, electric strength being 100%, in the pulse charging unit of Arkadiev-Marx generator being in operation for several years manifested their high efficiency; mutual group spread is ≤ ± 15 ns

  18. Do kV really make everything look grey? A comparative study of 600 kV computed tomography systems; Macht kV wirklich grau? Eine Vergleichsstudie zu 600 kV Computertomografiesystemen

    Energy Technology Data Exchange (ETDEWEB)

    Krumm, Michael; Sauerwein, Christoph; Haemmerle, Volker; Knupe, Gunnar [RayScan Technologies GmbH, Meersburg (Germany)

    2013-07-01

    In the automotive industry there is a manufacture of cast aluminium parts of considerable thickness. Growing importance is being attached to methods of nondestructive testing and full metrological characterisation of these parts. A major contribution to this end has been made by the latest generation of CT systems, whose 600 kV X-ray tubes and line detectors make for excellent image quality. The purpose of the present study was to make an objective assessment of the performance of these CT systems by examining the advantages and drawbacks of each. This included comparisons of various parameters such as tube voltage and exposure time as well as different tube and detector technologies and CT measurement methods.

  19. MFTF 230 kV pulsed power substation

    International Nuclear Information System (INIS)

    Wilson, J.H.

    1979-01-01

    The Mirror Fusion Test Facility (MFTF) currently under construction at the Lawrence Livermore Laboratory includes a Sustaining Neutral Beam Power Supply System (SNBPSS) consisting of 24 power-supply sets. The System will operate in long pulses (initially .5 seconds and eventually 30 seconds) at high power (200 MW), which will necessitate a large source of ac power. To meet this requirement, a new 230-kV substation is also being built at LLL. The constraints of cost, equipment protection, short operating lifetime (10 years), and reliability dictated a unique substation design. Its unusual features include provisions for fast fault detection and tripping, a capability for limiting ground fault current, low impedance, and economical design

  20. Faraday Rotator 5 kV Capacitor Bank

    International Nuclear Information System (INIS)

    Fetterman, C.C.

    1975-01-01

    A Faraday rotator 5 kV capacitor bank is a pulsed output power supply used to energize Faraday rotators for optical isolation in the ''LLL kJ Glass Laser System.'' Each supply contains either one, two or three parallel 240 μF storage capacitors depending on the size of the isolator used. Generally, the ''A*''(216 μH) isolator is energized with one capacitor, the ''A''(116 μH) isolator uses two capacitors and the ''B''(87 μH) isolator requires three capacitors. All models of isolators have been tested with four capacitors under maximum voltage and 25 feet of RG-217 cable with no hazardous effects. Except for the number of capacitors in each unit, the supplies are otherwise physically identical

  1. Wave speeds in the macroscopic extended model for ultrarelativistic gases

    Energy Technology Data Exchange (ETDEWEB)

    Borghero, F., E-mail: borghero@unica.it [Dip. Matematica e Informatica, Università di Cagliari, Via Ospedale 72, 09124 Cagliari (Italy); Demontis, F., E-mail: fdemontis@unica.it [Dip. Matematica, Università di Cagliari, Viale Merello 92, 09123 Cagliari (Italy); Pennisi, S., E-mail: spennisi@unica.it [Dip. Matematica, Università di Cagliari, Via Ospedale 72, 09124 Cagliari (Italy)

    2013-11-15

    Equations determining wave speeds for a model of ultrarelativistic gases are investigated. This model is already present in literature; it deals with an arbitrary number of moments and it was proposed in the context of exact macroscopic approaches in Extended Thermodynamics. We find these results: the whole system for the determination of the wave speeds can be divided into independent subsystems which are expressed by linear combinations, through scalar coefficients, of tensors all of the same order; some wave speeds, but not all of them, are expressed by square roots of rational numbers; finally, we prove that these wave speeds for the macroscopic model are the same of those furnished by the kinetic model.

  2. Analysis and Enhancements of a Prolific Macroscopic Model of Epilepsy

    Directory of Open Access Journals (Sweden)

    Christopher Fietkiewicz

    2016-01-01

    Full Text Available Macroscopic models of epilepsy can deliver surprisingly realistic EEG simulations. In the present study, a prolific series of models is evaluated with regard to theoretical and computational concerns, and enhancements are developed. Specifically, we analyze three aspects of the models: (1 Using dynamical systems analysis, we demonstrate and explain the presence of direct current potentials in the simulated EEG that were previously undocumented. (2 We explain how the system was not ideally formulated for numerical integration of stochastic differential equations. A reformulated system is developed to support proper methodology. (3 We explain an unreported contradiction in the published model specification regarding the use of a mathematical reduction method. We then use the method to reduce the number of equations and further improve the computational efficiency. The intent of our critique is to enhance the evolution of macroscopic modeling of epilepsy and assist others who wish to explore this exciting class of models further.

  3. Problems related to macroscopic electric fields in the magnetosphere

    International Nuclear Information System (INIS)

    Faelthammar, C.

    1977-01-01

    The macroscopic electric fields in the magnetosphere originate from internal as well as external sources. The fields are intimately coupled with the dynamics of magnetospheric plasma convection. They also depend on the complicated electrical properties of the hot collisionless plasma. Macroscopic electric fields are responsible for some important kinds of energization of charged particles that take place in the magnetosphere and affect not only particles of auroral energy but also, by multistep processes, trapped high-energy particles. A particularly interesting feature of magnetospheric electric fields is that they can have substantial components along the geomagnetic field, as has recently been confirmed by observations. Several physical mechanisms have been identified by which such electric fields can be supported even when collisions between particles are negligible. Comments are made on the magnetic mirror effect, anomalous resistivity, the collisionless thermoelectric effect, and electric double layers, emphasizing key features and differences and their significance in the light of recent observational data

  4. Macroscopic balance equations for two-phase flow models

    International Nuclear Information System (INIS)

    Hughes, E.D.

    1979-01-01

    The macroscopic, or overall, balance equations of mass, momentum, and energy are derived for a two-fluid model of two-phase flows in complex geometries. These equations provide a base for investigating methods of incorporating improved analysis methods into computer programs, such as RETRAN, which are used for transient and steady-state thermal-hydraulic analyses of nuclear steam supply systems. The equations are derived in a very general manner so that three-dimensional, compressible flows can be analysed. The equations obtained supplement the various partial differential equation two-fluid models of two-phase flow which have recently appeared in the literature. The primary objective of the investigation is the macroscopic balance equations. (Auth.)

  5. Optimization of 200 kV electrostatic accelerator

    Directory of Open Access Journals (Sweden)

    M Nazmabadi

    2015-09-01

    Full Text Available Optimizations on 200 kV electrostatic accelerator have been done in order to increasing ion current on target, improving vacuum condition and reduction in x-rays emission, increasing stability of high voltage power supply and reaching much greater achievable voltage value. The accelerator tube has most important effect on beam tracing in the electrostatic accelerators. So precautions most be considered in designing and constructing of this part. In order to finding permissible tolerances in construction and assembling of 200 kV electrostatic accelerator column, first the effects of angle deviation of a part from accelerator axis on beam track in the accelerator tube was simulated with Simion 7.0 computer program. We found that in order to prevent beam lost, the tolerances of balancing and co-centering of each part should be smaller than 0.1 mm. Each part of accelerator tube constructed by tolerances lower than 0.05 mm. Ultrasonic cleaning method used in pre-assembling process of parts. Because of its excellences, in the new tube we used borosilicate glass instead of high density alumina as insulators between the metallic electrodes. After three days of working vacuum pumps the system reached to 8.0×10-7 and after months to 5.0×10-7 ultimate pressure values. Measurements showed that by these considerations the maximum of reachable ion current on target was 1.1 mA which increased 50% compared to old machine, while x-ray emission intensity was increased by 25%. Optimizations of high voltage power supply are now under studies and tests

  6. The voltage-gated potassium channel subunit, Kv1.3, is expressed in epithelia

    DEFF Research Database (Denmark)

    Grunnet, Morten; Rasmussen, Hanne B; Hay-Schmidt, Anders

    2003-01-01

    The Shaker-type voltage-gated potassium channel, Kv1.3, is believed to be restricted in distribution to lymphocytes and neurons. In lymphocytes, this channel has gained intense attention since it has been proven that inhibition of Kv1.3 channels compromise T lymphocyte activation. To investigate...

  7. PKC and AMPK regulation of Kv1.5 potassium channels

    DEFF Research Database (Denmark)

    Andersen, Martin Nybo; Skibsbye, Lasse; Tang, Chuyi

    2015-01-01

    The voltage-gated Kv1.5 potassium channel, conducting the ultra-rapid rectifier K(+) current (IKur), is regulated through several pathways. Here we investigate if Kv1.5 surface expression is controlled by the 2 kinases PKC and AMPK, using Xenopus oocytes, MDCK cells and atrial derived HL-1 cells....

  8. harmonic load modeling: a case study of 33 kv abuja steel mill feeder

    African Journals Online (AJOL)

    HOD

    techniques are adopted. This paper studied the harmonic orders of the 33 kV Abuja Steel Feeder modeled as a ... (ETAP) software package was deployed to perform Discrete Fast Transform (DFT) while the input ... and documented in research and development articles ... network with 33kV Abuja Steel feeder as case study.

  9. Pharmacological dissection of K(v)7.1 channels in systemic and pulmonary arteries

    DEFF Research Database (Denmark)

    Chadha, Preet S; Zunke, Friederike; Davis, Alison J

    2012-01-01

    The aim of this study was to characterize the functional impact of KCNQ1-encoded voltage-dependent potassium channels (K(v)7.1) in the vasculature.......The aim of this study was to characterize the functional impact of KCNQ1-encoded voltage-dependent potassium channels (K(v)7.1) in the vasculature....

  10. Development of a 300-kV Marx generator and its application to drive ...

    Indian Academy of Sciences (India)

    Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, ... anode gap of 7·5 mm, an REB having beam voltage 160 kV and duration 150 ns ... lowest stage has a triggered SG which is closed by a 6 kV pulse obtained with the ...

  11. A study on the insulation coordination of 765 kV system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Boo; Shim, Eung Bo [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Lee, Yong Han; Youn, Jae Yeong; Hwang, Chi Woo; Jung, Dong Hak [Korea Electrotechnology Research Inst., Changwon (Korea, Republic of)

    1996-12-31

    Analysis of the power frequency temporary overvoltage. Analysis of switching surges - Fault imitation, closing and re closing, fault clearing. Analysis of lightning surges. Insulation design of 765 kV overhead transmission line. Insulation coordination of 765 kV gas insulated substation. Transient recovery voltage and high speed ground switch (author). 38 refs., 55 figs.

  12. Kv10.1 potassium channel: from the brain to the tumors.

    Science.gov (United States)

    Cázares-Ordoñez, V; Pardo, L A

    2017-10-01

    The KCNH1 gene encodes the Kv10.1 (Eag1) ion channel, a member of the EAG (ether-à-go-go) family of voltage-gated potassium channels. Recent studies have demonstrated that KCHN1 mutations are implicated in Temple-Baraitser and Zimmermann-Laband syndromes and other forms of developmental deficits that all present with mental retardation and epilepsy, suggesting that Kv10.1 might be important for cognitive development in humans. Although the Kv10.1 channel is mainly expressed in the mammalian brain, its ectopic expression occurs in 70% of human cancers. Cancer cells and tumors expressing Kv10.1 acquire selective advantages that favor cancer progression through molecular mechanisms that involve several cellular pathways, indicating that protein-protein interactions may be important for Kv10.1 influence in cell proliferation and tumorigenesis. Several studies on transcriptional and post-transcriptional regulation of Kv10.1 expression have shown interesting mechanistic insights about Kv10.1 role in oncogenesis, increasing the importance of identifying the cellular factors that regulate Kv10.1 expression in tumors.

  13. KCNE3 is an inhibitory subunit of the Kv4.3 potassium channel

    DEFF Research Database (Denmark)

    Lundby, Alicia; Olesen, Søren-Peter

    2006-01-01

    The mammalian Kv4.3 potassium channel is a fast activating and inactivating K+ channel widely distributed in mammalian tissues. Kv4.3 is the major component of various physiologically important currents ranging from A-type currents in the CNS to the transient outward potassium conductance in the ...

  14. Macroscopic phase separation in high-temperature superconductors

    Science.gov (United States)

    Wen, Hai-Hu

    2000-01-01

    High-temperature superconductivity is recovered by introducing extra holes to the Cu-O planes, which initially are insulating with antiferromagnetism. In this paper I present data to show the macroscopic electronic phase separation that is caused by either mobile doping or electronic instability in the overdoped region. My results clearly demonstrate that the electronic inhomogeneity is probably a general feature of high-temperature superconductors. PMID:11027323

  15. Negative heat capacity at phase-separation in macroscopic systems

    OpenAIRE

    Gross, D. H. E.

    2005-01-01

    Systems with long-range as well with short-range interactions should necessarily have a convex entropy S(E) at proper phase transitions of first order, i.e. when a separation of phases occurs. Here the microcanonical heat capacity c(E)= -\\frac{(\\partial S/\\partial E)^2}{\\partial^2S/\\partial E^2} is negative. This should be observable even in macroscopic systems when energy fluctuations with the surrounding world can be sufficiently suppressed.

  16. Extension of Seismic Scanning Tunneling Macroscope to Elastic Waves

    KAUST Repository

    Tarhini, Ahmad

    2017-11-06

    The theory for the seismic scanning tunneling macroscope is extended from acoustic body waves to elastic body-wave propagation. We show that, similar to the acoustic case, near-field superresolution imaging from elastic body waves results from the O(1/R) term, where R is the distance between the source and near-field scatterer. The higher-order contributions R−n for n>1 are cancelled in the near-field region for a point source with normal stress.

  17. A macroscopic model for magnetic shape-memory single crystals

    Czech Academy of Sciences Publication Activity Database

    Bessoud, A. L.; Kružík, Martin; Stefanelli, U.

    2013-01-01

    Roč. 64, č. 2 (2013), s. 343-359 ISSN 0044-2275 R&D Projects: GA AV ČR IAA100750802; GA ČR GAP201/10/0357 Institutional support: RVO:67985556 Keywords : magnetostriction * evolution Subject RIV: BA - General Mathematics Impact factor: 1.214, year: 2013 http://library.utia.cas.cz/separaty/2012/MTR/kruzik-a macroscopic model for magnetic shape- memory single crystals.pdf

  18. Extension of Seismic Scanning Tunneling Macroscope to Elastic Waves

    KAUST Repository

    Tarhini, Ahmad; Guo, Bowen; Dutta, Gaurav; Schuster, Gerard T.

    2017-01-01

    The theory for the seismic scanning tunneling macroscope is extended from acoustic body waves to elastic body-wave propagation. We show that, similar to the acoustic case, near-field superresolution imaging from elastic body waves results from the O(1/R) term, where R is the distance between the source and near-field scatterer. The higher-order contributions R−n for n>1 are cancelled in the near-field region for a point source with normal stress.

  19. Toward a superconducting quantum computer. Harnessing macroscopic quantum coherence.

    Science.gov (United States)

    Tsai, Jaw-Shen

    2010-01-01

    Intensive research on the construction of superconducting quantum computers has produced numerous important achievements. The quantum bit (qubit), based on the Josephson junction, is at the heart of this research. This macroscopic system has the ability to control quantum coherence. This article reviews the current state of quantum computing as well as its history, and discusses its future. Although progress has been rapid, the field remains beset with unsolved issues, and there are still many new research opportunities open to physicists and engineers.

  20. Pseudo-Goldstone bosons and new macroscopic forces

    International Nuclear Information System (INIS)

    Hill, C.T.; Ross, G.G.

    1988-01-01

    Pseudoscalar Goldstone bosons may readily be associated with weakly, explicitly broken symmetries giving them mixed CP quantum numbers. In general this leads to scalar couplings to nucleons and leptons, which produces coherent long range forces. This can naturally accommodate detectable long range macroscopic forces mediated by bosons completely consistent with conventional cosmological limits, e.g., new interactions with the range of present 'fifth force' searches which probe a scale of new physics of f ≅ 10 14 GeV. (orig.)

  1. Macroscopic quantum electrodynamics of high-Q cavities

    International Nuclear Information System (INIS)

    Khanbekyan, Mikayel

    2009-01-01

    In this thesis macroscopic quantum electrodynamics in linear media was applied in order to develop an universally valid quantum theory for the description of the interaction of the electromagnetic field with atomic sources in high-Q cavities. In this theory a complete description of the characteristics of the emitted radiation is given. The theory allows to show the limits of the applicability of the usually applied theory. In order to establish an as possible generally valid theory first the atom-field interaction was studied in the framework of macroscopic quantum electrodynamics in dispersive and absorptive media. In order to describe the electromagnetic field from Maxwell's equations was started, whereby the noise-current densities, which are connected with the absorption of the medium, were included. The solution of these equations expresses the electromagnetic field variables by the noise-current densities by means of Green's tensor of the macroscopic Maxwell equations. The explicit quantization is performed by means of the noise-current densities, whereby a diagonal Hamiltonian is introduced, which then guarantees the time development according to Maxwell's equation and the fulfillment of the fundamental simultaneous commutation relations of the field variables. In the case of the interaction of the medium-supported field with atoms the Hamiltonian must be extended by atom-field interactions energies, whereby the canonical coupling schemes of the minimal or multipolar coupling can be used. The dieelectric properties of the material bodies as well as their shape are coded in the Green tensor of the macroscopic Maxwell equations. As preparing step first the Green tensor was specified in order to derive three-dimensional input-output relations for the electromagnetic field operators on a plane multilayer structure. Such a general dewscription of the electromagnetic field allows the inclusion both of dispersion and absorption of the media and the possible

  2. From pan-reactive KV7 channel opener to subtype selective opener/inhibitor by addition of a methyl group.

    Directory of Open Access Journals (Sweden)

    Sigrid Marie Blom

    Full Text Available The voltage-gated potassium channels of the KV7 family (KV7.1-5 play important roles in controlling neuronal excitability and are therefore attractive targets for treatment of CNS disorders linked to hyperexcitability. One of the main challenges in developing KV7 channel active drugs has been to identify compounds capable of discriminating between the neuronally expressed subtypes (KV7.2-5, aiding the identification of the subunit composition of KV7 currents in various tissues, and possessing better therapeutic potential for particular indications. By taking advantage of the structure-activity relationship of acrylamide KV7 channel openers and the effects of these compounds on mutant KV7 channels, we have designed and synthesized a novel KV7 channel modulator with a unique profile. The compound, named SMB-1, is an inhibitor of KV7.2 and an activator of KV7.4. SMB-1 inhibits KV7.2 by reducing the current amplitude and increasing the time constant for the slow component of the activation kinetics. The activation of KV7.4 is seen as an increase in the current amplitude and a slowing of the deactivation kinetics. Experiments studying mutant channels with a compromised binding site for the KV7.2-5 opener retigabine indicate that SMB-1 binds within the same pocket as retigabine for both inhibition of KV7.2 and activation of KV7.4. SMB-1 may serve as a valuable tool for KV7 channel research and may be used as a template for further design of better subtype selective KV7 channel modulators. A compound with this profile could hold novel therapeutic potential such as the treatment of both positive and cognitive symptoms in schizophrenia.

  3. Deletion of the Kv2.1 delayed rectifier potassium channel leads to neuronal and behavioral hyperexcitability

    Science.gov (United States)

    Speca, David J.; Ogata, Genki; Mandikian, Danielle; Bishop, Hannah I.; Wiler, Steve W.; Eum, Kenneth; Wenzel, H. Jürgen; Doisy, Emily T.; Matt, Lucas; Campi, Katharine L.; Golub, Mari S.; Nerbonne, Jeanne M.; Hell, Johannes W.; Trainor, Brian C.; Sack, Jon T.; Schwartzkroin, Philip A.; Trimmer, James S.

    2014-01-01

    The Kv2.1 delayed rectifier potassium channel exhibits high-level expression in both principal and inhibitory neurons throughout the central nervous system, including prominent expression in hippocampal neurons. Studies of in vitro preparations suggest that Kv2.1 is a key yet conditional regulator of intrinsic neuronal excitability, mediated by changes in Kv2.1 expression, localization and function via activity-dependent regulation of Kv2.1 phosphorylation. Here we identify neurological and behavioral deficits in mutant (Kv2.1−/−) mice lacking this channel. Kv2.1−/− mice have grossly normal characteristics. No impairment in vision or motor coordination was apparent, although Kv2.1−/− mice exhibit reduced body weight. The anatomic structure and expression of related Kv channels in the brains of Kv2.1−/− mice appears unchanged. Delayed rectifier potassium current is diminished in hippocampal neurons cultured from Kv2.1−/− animals. Field recordings from hippocampal slices of Kv2.1−/− mice reveal hyperexcitability in response to the convulsant bicuculline, and epileptiform activity in response to stimulation. In Kv2.1−/− mice, long-term potentiation at the Schaffer collateral – CA1 synapse is decreased. Kv2.1−/− mice are strikingly hyperactive, and exhibit defects in spatial learning, failing to improve performance in a Morris Water Maze task. Kv2.1−/− mice are hypersensitive to the effects of the convulsants flurothyl and pilocarpine, consistent with a role for Kv2.1 as a conditional suppressor of neuronal activity. Although not prone to spontaneous seizures, Kv2.1−/− mice exhibit accelerated seizure progression. Together, these findings suggest homeostatic suppression of elevated neuronal activity by Kv2.1 plays a central role in regulating neuronal network function. PMID:24494598

  4. Macroscopic quantum mechanics: theory and experimental concepts of optomechanics

    International Nuclear Information System (INIS)

    Chen Yanbei

    2013-01-01

    Rapid experimental progress has recently allowed the use of light to prepare macroscopic mechanical objects into nearly pure quantum states. This research field of quantum optomechanics opens new doors towards testing quantum mechanics, and possibly other laws of physics, in new regimes. In the first part of this article, I will review a set of techniques of quantum measurement theory that are often used to analyse quantum optomechanical systems. Some of these techniques were originally designed to analyse how a classical driving force passes through a quantum system, and can eventually be detected with an optimal signal-to-noise ratio—while others focus more on the quantum-state evolution of a mechanical object under continuous monitoring. In the second part of this article, I will review a set of experimental concepts that will demonstrate quantum mechanical behaviour of macroscopic objects—quantum entanglement, quantum teleportation and the quantum Zeno effect. Taking the interplay between gravity and quantum mechanics as an example, I will review a set of speculations on how quantum mechanics can be modified for macroscopic objects, and how these speculations—and their generalizations—might be tested by optomechanics. (invited review)

  5. The mirrors model: macroscopic diffusion without noise or chaos

    International Nuclear Information System (INIS)

    Chiffaudel, Yann; Lefevere, Raphaël

    2016-01-01

    Before stating our main result, we first clarify through classical examples the status of the laws of macroscopic physics as laws of large numbers. We next consider the mirrors model in a finite d-dimensional domain and connected to particles reservoirs at fixed chemical potentials. The dynamics is purely deterministic and non-ergodic but takes place in a random environment. We study the macroscopic current of particles in the stationary regime. We show first that when the size of the system goes to infinity, the behaviour of the stationary current of particles is governed by the proportion of orbits crossing the system. This allows us to formulate a necessary and sufficient condition on the distribution of the set of orbits that ensures the validity of Fick’s law. Using this approach, we show that Fick’s law relating the stationary macroscopic current of particles to the concentration difference holds in three dimensions and above. The negative correlations between crossing orbits play a key role in the argument. (letter)

  6. Macroscopic phase-resetting curves for spiking neural networks

    Science.gov (United States)

    Dumont, Grégory; Ermentrout, G. Bard; Gutkin, Boris

    2017-10-01

    The study of brain rhythms is an open-ended, and challenging, subject of interest in neuroscience. One of the best tools for the understanding of oscillations at the single neuron level is the phase-resetting curve (PRC). Synchronization in networks of neurons, effects of noise on the rhythms, effects of transient stimuli on the ongoing rhythmic activity, and many other features can be understood by the PRC. However, most macroscopic brain rhythms are generated by large populations of neurons, and so far it has been unclear how the PRC formulation can be extended to these more common rhythms. In this paper, we describe a framework to determine a macroscopic PRC (mPRC) for a network of spiking excitatory and inhibitory neurons that generate a macroscopic rhythm. We take advantage of a thermodynamic approach combined with a reduction method to simplify the network description to a small number of ordinary differential equations. From this simplified but exact reduction, we can compute the mPRC via the standard adjoint method. Our theoretical findings are illustrated with and supported by numerical simulations of the full spiking network. Notably our mPRC framework allows us to predict the difference between effects of transient inputs to the excitatory versus the inhibitory neurons in the network.

  7. Macroscopic phase-resetting curves for spiking neural networks.

    Science.gov (United States)

    Dumont, Grégory; Ermentrout, G Bard; Gutkin, Boris

    2017-10-01

    The study of brain rhythms is an open-ended, and challenging, subject of interest in neuroscience. One of the best tools for the understanding of oscillations at the single neuron level is the phase-resetting curve (PRC). Synchronization in networks of neurons, effects of noise on the rhythms, effects of transient stimuli on the ongoing rhythmic activity, and many other features can be understood by the PRC. However, most macroscopic brain rhythms are generated by large populations of neurons, and so far it has been unclear how the PRC formulation can be extended to these more common rhythms. In this paper, we describe a framework to determine a macroscopic PRC (mPRC) for a network of spiking excitatory and inhibitory neurons that generate a macroscopic rhythm. We take advantage of a thermodynamic approach combined with a reduction method to simplify the network description to a small number of ordinary differential equations. From this simplified but exact reduction, we can compute the mPRC via the standard adjoint method. Our theoretical findings are illustrated with and supported by numerical simulations of the full spiking network. Notably our mPRC framework allows us to predict the difference between effects of transient inputs to the excitatory versus the inhibitory neurons in the network.

  8. Stochastic and Macroscopic Thermodynamics of Strongly Coupled Systems

    Directory of Open Access Journals (Sweden)

    Christopher Jarzynski

    2017-01-01

    Full Text Available We develop a thermodynamic framework that describes a classical system of interest S that is strongly coupled to its thermal environment E. Within this framework, seven key thermodynamic quantities—internal energy, entropy, volume, enthalpy, Gibbs free energy, heat, and work—are defined microscopically. These quantities obey thermodynamic relations including both the first and second law, and they satisfy nonequilibrium fluctuation theorems. We additionally impose a macroscopic consistency condition: When S is large, the quantities defined within our framework scale up to their macroscopic counterparts. By satisfying this condition, we demonstrate that a unifying framework can be developed, which encompasses both stochastic thermodynamics at one end, and macroscopic thermodynamics at the other. A central element in our approach is a thermodynamic definition of the volume of the system of interest, which converges to the usual geometric definition when S is large. We also sketch an alternative framework that satisfies the same consistency conditions. The dynamics of the system and environment are modeled using Hamilton’s equations in the full phase space.

  9. Macroscopic description of the limb muscles of Tupinambis merianae

    Directory of Open Access Journals (Sweden)

    Juliana Barbosa Casals

    2012-03-01

    Full Text Available Tegu lizard (Tupinambis merianae belongs to the Teiidae family. It is distributed throughout the Americas, with many species, including Brazilian ones. They are from the Tupinambis genus, the largest representatives of the Teiidae family. For this study three animals (run over coming from donation were used. The dissected lizards were fixed in 10%, formaldehyde, and the macroscopic analysis was carried out in a detailed and photo documented way, keeping the selected structures “in situ”. This paper had as its main aim contributing to the macroscopic description of the chest myology, as well as the thoracic and pelvic limbs of the lizard T. merianae. The results obtained from this research were compared to authors who have studied animals from the same Reptilia class. Thus, we conclude that our macroscopic results are similar to those already described by the researchers Hildebrand (1995, Moro and Abdala (2004 and Abdala and Diogo (2010. We should highlight that the knowledge on anatomy has importance and applications to various areas within Biology, contributing in a substantial way to the areas of human health and technology.

  10. Micromechanical study of macroscopic friction and dissipation in idealised granular materials: the effect of interparticle friction

    NARCIS (Netherlands)

    Kruyt, Nicolaas P.; Gutkowski, Witold; Rothenburg, L.; Kowalewski, Tomasz A.

    2004-01-01

    Using Discrete Element Method (DEM) simulations with varying interparticle friction coefficient, the relation between interparticle friction coefficient and macroscopic continuum friction and dissipation is investigated. As expected, macroscopic friction and dilatancy increase with interparticle

  11. Solvable Quantum Macroscopic Motions and Decoherence Mechanisms in Quantum Mechanics on Nonstandard Space

    Science.gov (United States)

    Kobayashi, Tsunehiro

    1996-01-01

    Quantum macroscopic motions are investigated in the scheme consisting of N-number of harmonic oscillators in terms of ultra-power representations of nonstandard analysis. Decoherence is derived from the large internal degrees of freedom of macroscopic matters.

  12. 14C SIRI samples at CNA: Measurements at 200 kV and 1000 kV

    International Nuclear Information System (INIS)

    Santos Arévalo, Francisco-Javier; Gómez Martínez, Isabel; Agulló García, Lidia

    2015-01-01

    The Sixth International Radiocarbon Intercomparison (SIRI) exercise has taken place during late 2013 and 2014. 13 samples were distributed for AMS (Accelerator Mass Spectrometry) and 5 for radiometric laboratories, including one sample exclusively for radiometric laboratories. Being the first opportunity for our laboratory to participate actively in an intercomparison exercise, we have prepared and measured the samples in the two existing AMS dedicated facilities at the Centro Nacional de Aceleradores (CNA): SARA (Spanish Accelerator for Radionuclide Analysis), a 1 MV multielemental AMS system from HVEE, and Micadas, a 200 kV radiocarbon dating system designed by ETH. Results are presented for the two systems, together with a description of both the sample preparation and measurement procedures.

  13. {sup 14}C SIRI samples at CNA: Measurements at 200 kV and 1000 kV

    Energy Technology Data Exchange (ETDEWEB)

    Santos Arévalo, Francisco-Javier, E-mail: fj.santos@csic.es; Gómez Martínez, Isabel; Agulló García, Lidia

    2015-10-15

    The Sixth International Radiocarbon Intercomparison (SIRI) exercise has taken place during late 2013 and 2014. 13 samples were distributed for AMS (Accelerator Mass Spectrometry) and 5 for radiometric laboratories, including one sample exclusively for radiometric laboratories. Being the first opportunity for our laboratory to participate actively in an intercomparison exercise, we have prepared and measured the samples in the two existing AMS dedicated facilities at the Centro Nacional de Aceleradores (CNA): SARA (Spanish Accelerator for Radionuclide Analysis), a 1 MV multielemental AMS system from HVEE, and Micadas, a 200 kV radiocarbon dating system designed by ETH. Results are presented for the two systems, together with a description of both the sample preparation and measurement procedures.

  14. 14C SIRI samples at CNA: Measurements at 200 kV and 1000 kV

    Science.gov (United States)

    Santos Arévalo, Francisco-Javier; Gómez Martínez, Isabel; Agulló García, Lidia

    2015-10-01

    The Sixth International Radiocarbon Intercomparison (SIRI) exercise has taken place during late 2013 and 2014. 13 samples were distributed for AMS (Accelerator Mass Spectrometry) and 5 for radiometric laboratories, including one sample exclusively for radiometric laboratories. Being the first opportunity for our laboratory to participate actively in an intercomparison exercise, we have prepared and measured the samples in the two existing AMS dedicated facilities at the Centro Nacional de Aceleradores (CNA): SARA (Spanish Accelerator for Radionuclide Analysis), a 1 MV multielemental AMS system from HVEE, and Micadas, a 200 kV radiocarbon dating system designed by ETH. Results are presented for the two systems, together with a description of both the sample preparation and measurement procedures.

  15. Fundamental role for the KCNE4 ancillary subunit in Kv7.4 regulation of arterial tone

    DEFF Research Database (Denmark)

    Jepps, Thomas A; Carr, Georgina; Lundegaard, Pia R

    2015-01-01

    tone by Kv7 channels. In HEK cells expressing Kv7.4, co-expression of KCNE4 increased the membrane expression of Kv7.4 and significantly altered Kv7.4 current properties. Quantitative PCR analysis of different rat arteries found that the KCNE4 isoform predominated and proximity ligation experiments...... leads to reduced Kv7.4 membrane abundance, a depolarized membrane potential and an augmented response to vasoconstrictors. KCNE4 is a key regulator of the function and expression of Kv7.4 in vascular smooth muscle. ABSTRACT: The KCNE ancillary subunits (KCNE1-5) significantly alter the expression...... to reduced Kv7.4 membrane abundance, a depolarized membrane potential and an augmented response to vasoconstrictors. The present study is the first to demonstrate an integral role of KCNE4 in regulating the function and expression of Kv7.4 in vascular smooth muscle....

  16. In regard to the question of macroscopic differential diagnosis of alcoholic and dilated cardiomyopathy

    Directory of Open Access Journals (Sweden)

    O. V. Sokolova

    2014-01-01

    Full Text Available The differential diagnosis of alcoholic and dilated cardiomyopathy according to the macroscopic data is represented in the article. The identity of macroscopic changes of heart, related to alcoholic and dilated cardiomyopathy, cannot diagnose these diseases based on the macroscopic characteristics; especially if there are no other visceral manifestations typical for chronic alcoholism.

  17. Mitochondrial ultrastructure and glucose signaling pathways attributed to the Kv1.3 ion channel

    Directory of Open Access Journals (Sweden)

    Christopher P. Kovach

    2016-05-01

    Full Text Available Gene-targeted deletion of the potassium channel Kv1.3 (Kv1.3-/- results in ‘Super-smeller’ mice with a sensory phenotype that includes an increased olfactory ability linked to changes in olfactory circuitry, increased abundance of olfactory cilia, and increased expression of odorant receptors and the G-protein, Golf. Kv1.3-/- mice also have a metabolic phenotype including lower body weight and decreased adiposity, increased total energy expenditure (TEE, increased locomotor activity, and resistance to both diet- and genetic-induced obesity. We explored two cellular aspects to elucidate the mechanism by which loss of Kv1.3 channel in the olfactory bulb (OB may enhance glucose utilization and metabolic rate. First, using in situ hybridization we find that Kv1.3 and the insulin-dependent glucose transporter type 4 (GLUT4 is co-localized to the mitral cell layer of the OB. Disruption of Kv1.3 conduction via construction of a pore mutation (W386F Kv1.3 was sufficient to independently translocate GLUT4 to the plasma membrane in HEK 293 cells. Because olfactory sensory perception and the maintenance of action potential firing frequency by mitral cells of the OB is highly energy demanding and Kv1.3 is also expressed in mitochondria, we next explored the structure of this organelle in mitral cells. We challenged wildtype (WT and Kv1.3-/- male mice with a moderately high-fat diet (MHF, 31.8 % kcal fat for 4 months and then examined OB ultrastructure using transmission microscopy. In WT mice, mitochondria were significantly enlarged following diet-induced obesity (DIO and there were fewer mitochondria, likely due to mitophagy. Interestingly, mitochondria were significantly smaller in Kv1.3-/- mice compared with that of WT mice. Similar to their metabolic resistance to DIO, the Kv1.3-/- mice had unchanged mitochondria in terms of cross sectional area and abundance following a challenge with modified diet. We are very interested to understand how

  18. SU-E-I-23: A General KV Constrained Optimization of CNR for CT Abdominal Imaging

    International Nuclear Information System (INIS)

    Weir, V; Zhang, J

    2015-01-01

    Purpose: While Tube current modulation has been well accepted for CT dose reduction, kV adjusting in clinical settings is still at its early stage. This is mainly due to the limited kV options of most current CT scanners. kV adjusting can potentially reduce radiation dose and optimize image quality. This study is to optimize CT abdomen imaging acquisition based on the assumption of a continuous kV, with the goal to provide the best contrast to noise ratio (CNR). Methods: For a given dose (CTDIvol) level, the CNRs at different kV and pitches were measured with an ACR GAMMEX phantom. The phantom was scanned in a Siemens Sensation 64 scanner and a GE VCT 64 scanner. A constrained mathematical optimization was used to find the kV which led to the highest CNR for the anatomy and pitch setting. Parametric equations were obtained from polynomial fitting of plots of kVs vs CNRs. A suitable constraint region for optimization was chosen. Subsequent optimization yielded a peak CNR at a particular kV for different collimations and pitch setting. Results: The constrained mathematical optimization approach yields kV of 114.83 and 113.46, with CNRs of 1.27 and 1.11 at the pitch of 1.2 and 1.4, respectively, for the Siemens Sensation 64 scanner with the collimation of 32 x 0.625mm. An optimized kV of 134.25 and 1.51 CNR is obtained for a GE VCT 64 slice scanner with a collimation of 32 x 0.625mm and a pitch of 0.969. At 0.516 pitch and 32 x 0.625 mm an optimized kV of 133.75 and a CNR of 1.14 was found for the GE VCT 64 slice scanner. Conclusion: CNR in CT image acquisition can be further optimized with a continuous kV option instead of current discrete or fixed kV settings. A continuous kV option is a key for individualized CT protocols

  19. SU-E-I-23: A General KV Constrained Optimization of CNR for CT Abdominal Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Weir, V; Zhang, J [University of Kentucky, Lexington, KY (United States)

    2015-06-15

    Purpose: While Tube current modulation has been well accepted for CT dose reduction, kV adjusting in clinical settings is still at its early stage. This is mainly due to the limited kV options of most current CT scanners. kV adjusting can potentially reduce radiation dose and optimize image quality. This study is to optimize CT abdomen imaging acquisition based on the assumption of a continuous kV, with the goal to provide the best contrast to noise ratio (CNR). Methods: For a given dose (CTDIvol) level, the CNRs at different kV and pitches were measured with an ACR GAMMEX phantom. The phantom was scanned in a Siemens Sensation 64 scanner and a GE VCT 64 scanner. A constrained mathematical optimization was used to find the kV which led to the highest CNR for the anatomy and pitch setting. Parametric equations were obtained from polynomial fitting of plots of kVs vs CNRs. A suitable constraint region for optimization was chosen. Subsequent optimization yielded a peak CNR at a particular kV for different collimations and pitch setting. Results: The constrained mathematical optimization approach yields kV of 114.83 and 113.46, with CNRs of 1.27 and 1.11 at the pitch of 1.2 and 1.4, respectively, for the Siemens Sensation 64 scanner with the collimation of 32 x 0.625mm. An optimized kV of 134.25 and 1.51 CNR is obtained for a GE VCT 64 slice scanner with a collimation of 32 x 0.625mm and a pitch of 0.969. At 0.516 pitch and 32 x 0.625 mm an optimized kV of 133.75 and a CNR of 1.14 was found for the GE VCT 64 slice scanner. Conclusion: CNR in CT image acquisition can be further optimized with a continuous kV option instead of current discrete or fixed kV settings. A continuous kV option is a key for individualized CT protocols.

  20. Functional and Molecular Evidence for Kv7 Channel Subtypes in Human Detrusor from Patients with and without Bladder Outflow Obstruction

    DEFF Research Database (Denmark)

    Svalø, Julie; Sheykhzade, Majid; Nordling, Jørgen

    2015-01-01

    The aim of the study was to investigate whether Kv7 channels and their ancillary β-subunits, KCNE, are functionally expressed in the human urinary bladder. Kv7 channels were examined at the molecular level and by functional studies using RT-qPCR and myography, respectively. We found mRNA expressi...... between Kv7 channels and β-adrenoceptors in the human urinary bladder. The performed gene expression analysis combined with the organ bath studies imply that compounds that activate Kv7 channels could be useful for treatment of overactive bladder syndrome.......The aim of the study was to investigate whether Kv7 channels and their ancillary β-subunits, KCNE, are functionally expressed in the human urinary bladder. Kv7 channels were examined at the molecular level and by functional studies using RT-qPCR and myography, respectively. We found mRNA expression...... (activator of Kv7.1 channels, 10 μM) and ML213 (activator of Kv7.2, Kv7.4, Kv7.4/7.5 and Kv7.5 channels, 10 μM), reduced the tone of 1 μM carbachol pre-constricted bladder strips. XE991 (blocker of Kv7.1-7.5 channels, 10 μM) had opposing effects as it increased contractions achieved with 20 mM KPSS...

  1. KCNE1 constrains the voltage sensor of Kv7.1 K+ channels.

    Directory of Open Access Journals (Sweden)

    Liora Shamgar

    Full Text Available Kv7 potassium channels whose mutations cause cardiovascular and neurological disorders are members of the superfamily of voltage-gated K(+ channels, comprising a central pore enclosed by four voltage-sensing domains (VSDs and sharing a homologous S4 sensor sequence. The Kv7.1 pore-forming subunit can interact with various KCNE auxiliary subunits to form K(+ channels with very different gating behaviors. In an attempt to characterize the nature of the promiscuous gating of Kv7.1 channels, we performed a tryptophan-scanning mutagenesis of the S4 sensor and analyzed the mutation-induced perturbations in gating free energy. Perturbing the gating energetics of Kv7.1 bias most of the mutant channels towards the closed state, while fewer mutations stabilize the open state or the inactivated state. In the absence of auxiliary subunits, mutations of specific S4 residues mimic the gating phenotypes produced by co-assembly of Kv7.1 with either KCNE1 or KCNE3. Many S4 perturbations compromise the ability of KCNE1 to properly regulate Kv7.1 channel gating. The tryptophan-induced packing perturbations and cysteine engineering studies in S4 suggest that KCNE1 lodges at the inter-VSD S4-S1 interface between two adjacent subunits, a strategic location to exert its striking action on Kv7.1 gating functions.

  2. Macroscopic polarization in crystalline dielectrics: the geometric phase approach

    International Nuclear Information System (INIS)

    Resta, R.

    1994-01-01

    The macroscopic electric polarization of a crystal is often defined as the dipole of a unit cell. In fact, such a dipole moment is ill defined, and the above definition is incorrect. Looking more closely, the quantity generally measured is differential polarization, defined with respect to a ''reference state'' of the same material. Such differential polarizations include either derivatives of the polarization (dielectric permittivity, Born effective charges, piezoelectricity, pyroelectricity) or finite differences (ferroelectricity). On the theoretical side, the differential concept is basic as well. Owing to continuity, a polarization difference is equivalent to a macroscopic current, which is directly accessible to the theory as a bulk property. Polarization is a quantum phenomenon and cannot be treated with a classical model, particularly whenever delocalized valence electrons are present in the dielectric. In a quantum picture, the current is basically a property of the phase of the wave functions, as opposed to the charge, which is a property of their modulus. An elegant and complete theory has recently been developed by King-Smith and Vanderbilt, in which the polarization difference between any two crystal states--in a null electric field--takes the form of a geometric quantum phase. This gives a comprehensive account of this theory, which is relevant for dealing with transverse-optic phonons, piezoelectricity, and ferroelectricity. Its relation to the established concepts of linear-response theory is also discussed. Within the geometric phase approach, the relevant polarization difference occurs as the circuit integral of a Berry connection (or ''vector potential''), while the corresponding curvature (or ''magnetic field'') provides the macroscopic linear response

  3. The secret life of ion channels: Kv1.3 potassium channels and proliferation.

    Science.gov (United States)

    Pérez-García, M Teresa; Cidad, Pilar; López-López, José R

    2018-01-01

    Kv1.3 channels are involved in the switch to proliferation of normally quiescent cells, being implicated in the control of cell cycle in many different cell types and in many different ways. They modulate membrane potential controlling K + fluxes, sense changes in potential, and interact with many signaling molecules through their intracellular domains. From a mechanistic point of view, we can describe the role of Kv1.3 channels in proliferation with at least three different models. In the "membrane potential model," membrane hyperpolarization resulting from Kv1.3 activation provides the driving force for Ca 2+ influx required to activate Ca 2+ -dependent transcription. This model explains most of the data obtained from several cells from the immune system. In the "voltage sensor model," Kv1.3 channels serve mainly as sensors that transduce electrical signals into biochemical cascades, independently of their effect on membrane potential. Kv1.3-dependent proliferation of vascular smooth muscle cells (VSMCs) could fit this model. Finally, in the "channelosome balance model," the master switch determining proliferation may be related to the control of the Kv1.3 to Kv1.5 ratio, as described in glial cells and also in VSMCs. Since the three mechanisms cannot function independently, these models are obviously not exclusive. Nevertheless, they could be exploited differentially in different cells and tissues. This large functional flexibility of Kv1.3 channels surely gives a new perspective on their functions beyond their elementary role as ion channels, although a conclusive picture of the mechanisms involved in Kv1.3 signaling to proliferation is yet to be reached.

  4. X irradiation of human epidermis in vitro. 2. Comparison of single 44 kV and 200 kV X irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wollina, U; Fueller, J; Burger, B; Hipler, C

    1989-01-01

    On the example of the reduction of epidermal adhesion of FITC wheat germ agglutinine (WGA) the direct membrane effect of a single X irradiation (44 kV and 220 kV) was analyzed in vitro. Human normal skin and psoriasis centres were compared. Normal skin showed no alteration of microscopically visible FITC-WGA adhesion on epidermal cells over the whole dose range. Foci of psoriasis responded to doses of /ge/ 5 Gy (44 and 220 kV) with a drastic reduction of epidermal lectin binding to lower and medium cell layers. Maximum efficacy was with 5 Gy (44 kV) or 10 Gy (220 kV). A dose elevation up to 20 Gy did not result in an increase of efficacy. Topographically the radiosensitive FITC-WGA adhesion could chiefly be seen in the dermal ridges. The findings support the impression of an increased radiosensitivity of the lesional psoriatic epidermis compared with normal skin. This is connected with an abnormal differentiation of keratinocytes in psoriasis. (author).

  5. Development and use of 60 kV, and 150 kV floating deck modulators for high voltage protection of multi-megawatt ion beam accelerators

    International Nuclear Information System (INIS)

    Barber, G.C.; Ponte, N.S.; Schilling, G.

    1977-01-01

    Extraction currents of 60 A at 40 kV have been produced by utilizing a 60 kV floating deck modulator interfaced to a high voltage power supply. The modulator is operated in a series mode to repetitively pulse power to the ion beam accelerator. Current monitoring and other protective circuits provide interrupt commands to the series switch tube when faults occur. The constant current characteristics of the water cooled tetrode and the rapid response of the protective circuits effectively limit the fault energy to the ion source. Three of the 60 kV decks have been modified and stacked in a series configuration to supply 150 kV, 50 A pulses. This system supplies power for development of higher-energy multi-grid sources. In this system attention has been focused on forced voltage sharing of the three decks and on protective circuits for fault conditions. All control signal processing and conditioning is performed at ground level. Fiber optic links are used to interface with the high potential associated with the floating decks. A shunt modulator incorporated with this system provides regulation of the voltage to the ion source gradient grid. Future modulator development includes a system to deliver 100 A at 80 kV

  6. Macroscopic influence on the spontaneous symmetry breaking in quantum field

    International Nuclear Information System (INIS)

    Kirzhnitz, D.A.

    1977-01-01

    Major results of investigations concerning macroscopic influence (heating, compression, external field and current) on elementary particle systems with spontaneous symmetry breaking are briefly reviewed. The study of this problem has been stimulated by recent progress in the unified renormalizable theory of elementary particles. Typically it appears that at some values of external parameters a phase transition with symmetry restoration takes place. There exists a profound and far going analogy with phase transition in many-body physics especially with superconductivity phenomenon. Some applications to cosmology are also considered

  7. Macroscopic relationship in primal-dual portfolio optimization problem

    Science.gov (United States)

    Shinzato, Takashi

    2018-02-01

    In the present paper, using a replica analysis, we examine the portfolio optimization problem handled in previous work and discuss the minimization of investment risk under constraints of budget and expected return for the case that the distribution of the hyperparameters of the mean and variance of the return rate of each asset are not limited to a specific probability family. Findings derived using our proposed method are compared with those in previous work to verify the effectiveness of our proposed method. Further, we derive a Pythagorean theorem of the Sharpe ratio and macroscopic relations of opportunity loss. Using numerical experiments, the effectiveness of our proposed method is demonstrated for a specific situation.

  8. The Two-Time Interpretation and Macroscopic Time-Reversibility

    Directory of Open Access Journals (Sweden)

    Yakir Aharonov

    2017-03-01

    Full Text Available The two-state vector formalism motivates a time-symmetric interpretation of quantum mechanics that entails a resolution of the measurement problem. We revisit a post-selection-assisted collapse model previously suggested by us, claiming that unlike the thermodynamic arrow of time, it can lead to reversible dynamics at the macroscopic level. In addition, the proposed scheme enables us to characterize the classical-quantum boundary. We discuss the limitations of this approach and its broad implications for other areas of physics.

  9. Seismic scanning tunneling macroscope - Elastic simulations and Arizona mine test

    KAUST Repository

    Hanafy, Sherif M.; Schuster, Gerard T.

    2012-01-01

    Elastic seismic simulations and field data tests are used to validate the theory of a seismic scanning tunneling macroscope (SSTM). For nearfield elastic simulation, the SSTM results show superresolution to be better than λ/8 if the only scattered data are used as input data. If the direct P and S waves are muted then the resolution of the scatterer locations are within about λ/5. Seismic data collected in an Arizona tunnel showed a superresolution limit of at least λ/19. These test results are consistent with the theory of the SSTM and suggest that the SSTM can be a tool used by geophysicists as a probe for near-field scatterers.

  10. GRUCAL, a computer program for calculating macroscopic group constants

    International Nuclear Information System (INIS)

    Woll, D.

    1975-06-01

    Nuclear reactor calculations require material- and composition-dependent, energy averaged nuclear data to describe the interaction of neutrons with individual isotopes in material compositions of reactor zones. The code GRUCAL calculates these macroscopic group constants for given compositions from the material-dependent data of the group constant library GRUBA. The instructions for calculating group constants are not fixed in the program, but will be read at the actual execution time from a separate instruction file. This allows to accomodate GRUCAL to various problems or different group constant concepts. (orig.) [de

  11. Conductance fluctuations in a macroscopic 3-dimensional Anderson insulator

    International Nuclear Information System (INIS)

    Sanquer, M.

    1990-01-01

    We report magnetoconductance experiment on a amorphous Y x -Si 1-x alloy (∼0.3). which is an Anderson insulator where spin-orbit scattering is strong. Two principal and new features emerge from the data: the first one is an halving of the localization length by the application of a magnetic field of about 2.5 Teslas. This effect is predicted by a new approach of transport in Anderson insulators where basic symetry considerations are the most important ingredient. The second one is the observation of reproducible conductance fluctuations at very low temperature in this macroscopic 3 D amorphous material

  12. A simple vibrating sample magnetometer for macroscopic samples

    Science.gov (United States)

    Lopez-Dominguez, V.; Quesada, A.; Guzmán-Mínguez, J. C.; Moreno, L.; Lere, M.; Spottorno, J.; Giacomone, F.; Fernández, J. F.; Hernando, A.; García, M. A.

    2018-03-01

    We here present a simple model of a vibrating sample magnetometer (VSM). The system allows recording magnetization curves at room temperature with a resolution of the order of 0.01 emu and is appropriated for macroscopic samples. The setup can be mounted with different configurations depending on the requirements of the sample to be measured (mass, saturation magnetization, saturation field, etc.). We also include here examples of curves obtained with our setup and comparison curves measured with a standard commercial VSM that confirms the reliability of our device.

  13. Development of 600 kV triple resonance pulse transformer.

    Science.gov (United States)

    Li, Mingjia; Zhang, Faqiang; Liang, Chuan; Xu, Zhou

    2015-06-01

    In this paper, a triple-resonance pulse transformer based on an air-core transformer is introduced. The voltage across the high-voltage winding of the air-core transformer is significantly less than the output voltage; instead, the full output voltage appears across the tuning inductor. The maximum ratio of peak load voltage to peak transformer voltage is 2.77 in theory. By analyzing pulse transformer's lossless circuit, the analytical expression for the output voltage and the characteristic equation of the triple-resonance circuit are presented. Design method for the triple-resonance pulse transformer (iterated simulation method) is presented, and a triple-resonance pulse transformer is developed based on the existing air-core transformer. The experimental results indicate that the maximum ratio of peak voltage across the load to peak voltage across the high-voltage winding of the air-core transformer is approximately 2.0 and the peak output voltage of the triple-resonance pulse transformer is approximately 600 kV.

  14. Accurate Iterative Analysis of the K-V Equations

    CERN Document Server

    Anderson, Oscar A

    2005-01-01

    Previous solutions of the K-V equations have either yielded poor accuracy or have been complex and difficult to follow. We describe a new approach, simple in concept, easy to use, with accuracy substantially improved over previous treatments. The results are given in the same form as the smooth approximation but include a few correction terms obtained from the field gradient integrated along the axis of a quadrupole cell. The input quantities–quadrupole field, beam current, and emittance–yield the average beam radius, the maximum envelope excursion, and the depressed and undepressed tunes. For all values of the input parameters, the results are much closer to the exact values from simulations than are results from the smooth approximation. For example, with the parameters adjusted for an exact phase advance of 83.4 degrees and 50% tune depression, both tunes are in error by less than 0.5%–over 22 times better than the smooth approximation. The error in maximum radius is 0.04%, impro...

  15. Novel Kv7.1-phosphatidylinositol 4,5-bisphosphate interaction sites uncovered by charge neutralization scanning

    DEFF Research Database (Denmark)

    Eckey, Karina; Wrobel, Eva; Strutz-Seebohm, Nathalie

    2014-01-01

    Kv7.1 to Kv7.5 α-subunits belong to the family of voltage-gated potassium channels (Kv). Assembled with the β-subunit KCNE1, Kv7.1 conducts the slowly activating potassium current IKs, which is one of the major currents underlying repolarization of the cardiac action potential. A known regulator...... of corresponding long QT syndrome mutants suggested impaired PIP2 regulation as the cause for channel dysfunction. To clarify the underlying structural mechanism of PIP2 binding, molecular dynamics simulations of Kv7.1/KCNE1 complexes containing two PIP2 molecules in each subunit at specific sites were performed...

  16. Macroscopic superposition states and decoherence by quantum telegraph noise

    Energy Technology Data Exchange (ETDEWEB)

    Abel, Benjamin Simon

    2008-12-19

    In the first part of the present thesis we address the question about the size of superpositions of macroscopically distinct quantum states. We propose a measure for the ''size'' of a Schroedinger cat state, i.e. a quantum superposition of two many-body states with (supposedly) macroscopically distinct properties, by counting how many single-particle operations are needed to map one state onto the other. We apply our measure to a superconducting three-junction flux qubit put into a superposition of clockwise and counterclockwise circulating supercurrent states and find this Schroedinger cat to be surprisingly small. The unavoidable coupling of any quantum system to many environmental degrees of freedom leads to an irreversible loss of information about an initially prepared superposition of quantum states. This phenomenon, commonly referred to as decoherence or dephasing, is the subject of the second part of the thesis. We have studied the time evolution of the reduced density matrix of a two-level system (qubit) subject to quantum telegraph noise which is the major source of decoherence in Josephson charge qubits. We are able to derive an exact expression for the time evolution of the reduced density matrix. (orig.)

  17. An exploration for the macroscopic physical meaning of entropy

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The macroscopic physical meaning of entropy is analyzed based on the exergy (availability) of a combined system (a closed system and its environment), which is the maximum amount of useful work obtainable from the system and the environment as the system is brought into equilibrium with the environment. The process the system experiences can be divided in two sequent sub-processes, the process at constant volume, which represents the heat interaction of the system with the environment, and the adiabatic process, which represents the work interaction of the system with the environment. It is shown that the macroscopic physical meaning of entropy is a measure of the unavailable energy of a closed system for doing useful work through heat interaction. This statement is more precise than those reported in prior literature. The unavailability function of a closed system can be defined as T0S and p0V in volume constant process and adiabatic process, respectively. Their changes, that is, AiTgS) and A (p0V) represent the unusable parts of the internal energy of a closed system for doing useful work in corresponding processes. Finally, the relation between Clausius entropy and Boltzmann entropy is discussed based on the comparison of their expressions for absolute entropy.

  18. Estimating minimum polycrystalline aggregate size for macroscopic material homogeneity

    International Nuclear Information System (INIS)

    Kovac, M.; Simonovski, I.; Cizelj, L.

    2002-01-01

    During severe accidents the pressure boundary of reactor coolant system can be subjected to extreme loadings, which might cause failure. Reliable estimation of the extreme deformations can be crucial to determine the consequences of severe accidents. Important drawback of classical continuum mechanics is idealization of inhomogenous microstructure of materials. Classical continuum mechanics therefore cannot predict accurately the differences between measured responses of specimens, which are different in size but geometrical similar (size effect). A numerical approach, which models elastic-plastic behavior on mesoscopic level, is proposed to estimate minimum size of polycrystalline aggregate above which it can be considered macroscopically homogeneous. The main idea is to divide continuum into a set of sub-continua. Analysis of macroscopic element is divided into modeling the random grain structure (using Voronoi tessellation and random orientation of crystal lattice) and calculation of strain/stress field. Finite element method is used to obtain numerical solutions of strain and stress fields. The analysis is limited to 2D models.(author)

  19. Macroscopic Theory for Evolving Biological Systems Akin to Thermodynamics.

    Science.gov (United States)

    Kaneko, Kunihiko; Furusawa, Chikara

    2018-05-20

    We present a macroscopic theory to characterize the plasticity, robustness, and evolvability of biological responses and their fluctuations. First, linear approximation in intracellular reaction dynamics is used to demonstrate proportional changes in the expression of all cellular components in response to a given environmental stress, with the proportion coefficient determined by the change in growth rate as a consequence of the steady growth of cells. We further demonstrate that this relationship is supported through adaptation experiments of bacteria, perhaps too well as this proportionality is held even across cultures of different types of conditions. On the basis of simulations of cell models, we further show that this global proportionality is a consequence of evolution in which expression changes in response to environmental or genetic perturbations are constrained along a unique one-dimensional curve, which is a result of evolutionary robustness. It then follows that the expression changes induced by environmental changes are proportionally reduced across different components of a cell by evolution, which is akin to the Le Chatelier thermodynamics principle. Finally, with the aid of a fluctuation-response relationship, this proportionality is shown to hold between fluctuations caused by genetic changes and those caused by noise. Overall, these results and support from the theoretical and experimental literature suggest a formulation of cellular systems akin to thermodynamics, in which a macroscopic potential is given by the growth rate (or fitness) represented as a function of environmental and evolutionary changes.

  20. Parametric equations for calculation of macroscopic cross sections

    International Nuclear Information System (INIS)

    Botelho, Mario Hugo; Carvalho, Fernando

    2015-01-01

    Neutronic calculations of the core of a nuclear reactor is one thing necessary and important for the design and management of a nuclear reactor in order to prevent accidents and control the reactor efficiently as possible. To perform these calculations a library of nuclear data, including cross sections is required. Currently, to obtain a cross section computer codes are used, which require a large amount of processing time and computer memory. This paper proposes the calculation of macroscopic cross section through the development of parametric equations. The paper illustrates the proposal for the case of macroscopic cross sections of absorption (Σa), which was chosen due to its greater complexity among other cross sections. Parametric equations created enable, quick and dynamic way, the determination of absorption cross sections, enabling the use of them in calculations of reactors. The results show efficient when compared with the absorption cross sections obtained by the ALPHA 8.8.1 code. The differences between the cross sections are less than 2% for group 2 and less than 0.60% for group 1. (author)

  1. A Macroscopic Multifractal Analysis of Parabolic Stochastic PDEs

    Science.gov (United States)

    Khoshnevisan, Davar; Kim, Kunwoo; Xiao, Yimin

    2018-05-01

    It is generally argued that the solution to a stochastic PDE with multiplicative noise—such as \\dot{u}= 1/2 u''+uξ, where {ξ} denotes space-time white noise—routinely produces exceptionally-large peaks that are "macroscopically multifractal." See, for example, Gibbon and Doering (Arch Ration Mech Anal 177:115-150, 2005), Gibbon and Titi (Proc R Soc A 461:3089-3097, 2005), and Zimmermann et al. (Phys Rev Lett 85(17):3612-3615, 2000). A few years ago, we proved that the spatial peaks of the solution to the mentioned stochastic PDE indeed form a random multifractal in the macroscopic sense of Barlow and Taylor (J Phys A 22(13):2621-2626, 1989; Proc Lond Math Soc (3) 64:125-152, 1992). The main result of the present paper is a proof of a rigorous formulation of the assertion that the spatio-temporal peaks of the solution form infinitely-many different multifractals on infinitely-many different scales, which we sometimes refer to as "stretch factors." A simpler, though still complex, such structure is shown to also exist for the constant-coefficient version of the said stochastic PDE.

  2. Parameterized representation of macroscopic cross section for PWR reactor

    International Nuclear Information System (INIS)

    Fiel, João Cláudio Batista; Carvalho da Silva, Fernando; Senra Martinez, Aquilino; Leal, Luiz C.

    2015-01-01

    Highlights: • This work describes a parameterized representation of the homogenized macroscopic cross section for PWR reactor. • Parameterization enables a quick determination of problem-dependent cross-sections to be used in few group calculations. • This work allows generating group cross-section data to perform PWR core calculations without computer code calculations. - Abstract: The purpose of this work is to describe, by means of Chebyshev polynomials, a parameterized representation of the homogenized macroscopic cross section for PWR fuel element as a function of soluble boron concentration, moderator temperature, fuel temperature, moderator density and 235 92 U enrichment. The cross-section data analyzed are fission, scattering, total, transport, absorption and capture. The parameterization enables a quick and easy determination of problem-dependent cross-sections to be used in few group calculations. The methodology presented in this paper will allow generation of group cross-section data from stored polynomials to perform PWR core calculations without the need to generate them based on computer code calculations using standard steps. The results obtained by the proposed methodology when compared with results from the SCALE code calculations show very good agreement

  3. Macroscopic Biological Characteristics of Individualized Therapy in Chinese Mongolian Osteopathy

    Science.gov (United States)

    Namula, Zhao; Mei, Wang; Li, Xue-en

    Objective: Chinese Mongolian osteopathy has been passed down from ancient times and includes unique practices and favorable efficacy. In this study, we investigate the macroscopic biological characteristics of individualized Chinese Mongolian osteopathy, in order to provide new principle and methods for the treatment of bone fracture. Method: With a view to provide a vital link between nature and humans, the four stages of Chinese Mongolian osteopathy focus on the unity of the mind and body, the limbs and body organs, the body and its functions, and humans and nature. Results: We discuss the merits of individualized osteopathy in terms of the underlying concepts, and evaluate the approaches and principles of traditional medicine, as well as biomechanics. Conclusions: Individualized Mongolian osteopathy targets macroscopic biological components including dynamic reduction, natural fixation, and functional healing. Chinese Mongolian osteopathy is a natural, ecological and non-invasive osteopathy that values the link between nature and humans, including the unity of mind and body. The biological components not only serve as a foundation for Chinese Mongolian osteopathy but are also important for the future development of modern osteopathy, focusing on individualization, actualization and integration.

  4. Macroscopic superposition states and decoherence by quantum telegraph noise

    International Nuclear Information System (INIS)

    Abel, Benjamin Simon

    2008-01-01

    In the first part of the present thesis we address the question about the size of superpositions of macroscopically distinct quantum states. We propose a measure for the ''size'' of a Schroedinger cat state, i.e. a quantum superposition of two many-body states with (supposedly) macroscopically distinct properties, by counting how many single-particle operations are needed to map one state onto the other. We apply our measure to a superconducting three-junction flux qubit put into a superposition of clockwise and counterclockwise circulating supercurrent states and find this Schroedinger cat to be surprisingly small. The unavoidable coupling of any quantum system to many environmental degrees of freedom leads to an irreversible loss of information about an initially prepared superposition of quantum states. This phenomenon, commonly referred to as decoherence or dephasing, is the subject of the second part of the thesis. We have studied the time evolution of the reduced density matrix of a two-level system (qubit) subject to quantum telegraph noise which is the major source of decoherence in Josephson charge qubits. We are able to derive an exact expression for the time evolution of the reduced density matrix. (orig.)

  5. Reversible optical control of macroscopic polarization in ferroelectrics

    Science.gov (United States)

    Rubio-Marcos, Fernando; Ochoa, Diego A.; Del Campo, Adolfo; García, Miguel A.; Castro, Germán R.; Fernández, José F.; García, José E.

    2018-01-01

    The optical control of ferroic properties is a subject of fascination for the scientific community, because it involves the establishment of new paradigms for technology1-9. Domains and domain walls are known to have a great impact on the properties of ferroic materials1-24. Progress is currently being made in understanding the behaviour of the ferroelectric domain wall, especially regarding its dynamic control10-12,17,19. New research is being conducted to find effective methodologies capable of modulating ferroelectric domain motion for future electronics. However, the practical use of ferroelectric domain wall motion should be both stable and reversible (rewritable) and, in particular, be able to produce a macroscopic response that can be monitored easily12,17. Here, we show that it is possible to achieve a reversible optical change of ferroelectric domains configuration. This effect leads to the tuning of macroscopic polarization and its related properties by means of polarized light, a non-contact external control. Although this is only the first step, it nevertheless constitutes the most crucial one in the long and complex process of developing the next generation of photo-stimulated ferroelectric devices.

  6. Inverted rank distributions: Macroscopic statistics, universality classes, and critical exponents

    Science.gov (United States)

    Eliazar, Iddo; Cohen, Morrel H.

    2014-01-01

    An inverted rank distribution is an infinite sequence of positive sizes ordered in a monotone increasing fashion. Interlacing together Lorenzian and oligarchic asymptotic analyses, we establish a macroscopic classification of inverted rank distributions into five “socioeconomic” universality classes: communism, socialism, criticality, feudalism, and absolute monarchy. We further establish that: (i) communism and socialism are analogous to a “disordered phase”, feudalism and absolute monarchy are analogous to an “ordered phase”, and criticality is the “phase transition” between order and disorder; (ii) the universality classes are characterized by two critical exponents, one governing the ordered phase, and the other governing the disordered phase; (iii) communism, criticality, and absolute monarchy are characterized by sharp exponent values, and are inherently deterministic; (iv) socialism is characterized by a continuous exponent range, is inherently stochastic, and is universally governed by continuous power-law statistics; (v) feudalism is characterized by a continuous exponent range, is inherently stochastic, and is universally governed by discrete exponential statistics. The results presented in this paper yield a universal macroscopic socioeconophysical perspective of inverted rank distributions.

  7. A Macroscopic Multifractal Analysis of Parabolic Stochastic PDEs

    Science.gov (United States)

    Khoshnevisan, Davar; Kim, Kunwoo; Xiao, Yimin

    2018-04-01

    It is generally argued that the solution to a stochastic PDE with multiplicative noise—such as \\dot{u}= 1/2 u''+uξ, where {ξ} denotes space-time white noise—routinely produces exceptionally-large peaks that are "macroscopically multifractal." See, for example, Gibbon and Doering (Arch Ration Mech Anal 177:115-150, 2005), Gibbon and Titi (Proc R Soc A 461:3089-3097, 2005), and Zimmermann et al. (Phys Rev Lett 85(17):3612-3615, 2000). A few years ago, we proved that the spatial peaks of the solution to the mentioned stochastic PDE indeed form a random multifractal in the macroscopic sense of Barlow and Taylor (J Phys A 22(13):2621-2626, 1989; Proc Lond Math Soc (3) 64:125-152, 1992). The main result of the present paper is a proof of a rigorous formulation of the assertion that the spatio-temporal peaks of the solution form infinitely-many different multifractals on infinitely-many different scales, which we sometimes refer to as "stretch factors." A simpler, though still complex, such structure is shown to also exist for the constant-coefficient version of the said stochastic PDE.

  8. Catalytic Growth of Macroscopic Carbon Nanofibers Bodies with Activated Carbon

    Science.gov (United States)

    Abdullah, N.; Rinaldi, A.; Muhammad, I. S.; Hamid, S. B. Abd.; Su, D. S.; Schlogl, R.

    2009-06-01

    Carbon-carbon composite of activated carbon and carbon nanofibers have been synthesized by growing Carbon nanofiber (CNF) on Palm shell-based Activated carbon (AC) with Ni catalyst. The composites are in an agglomerated shape due to the entanglement of the defective CNF between the AC particles forming a macroscopic body. The macroscopic size will allow the composite to be used as a stabile catalyst support and liquid adsorbent. The preparation of CNT/AC nanocarbon was initiated by pre-treating the activated carbon with nitric acid, followed by impregnation of 1 wt% loading of nickel (II) nitrate solutions in acetone. The catalyst precursor was calcined and reduced at 300° C for an hour in each step. The catalytic growth of nanocarbon in C2H4/H2 was carried out at temperature of 550° C for 2 hrs with different rotating angle in the fluidization system. SEM and N2 isotherms show the level of agglomeration which is a function of growth density and fluidization of the system. The effect of fluidization by rotating the reactor during growth with different speed give a significant impact on the agglomeration of the final CNF/AC composite and thus the amount of CNFs produced. The macrostructure body produced in this work of CNF/AC composite will have advantages in the adsorbent and catalyst support application, due to the mechanical and chemical properties of the material.

  9. Protein kinase A stimulates Kv7.1 surface expression by regulating Nedd4-2-dependent endocytic trafficking

    DEFF Research Database (Denmark)

    Andersen, Martin Nybo; Hefting, Louise Leth; Steffensen, Annette Buur

    2015-01-01

    The potassium channel Kv7.1 plays critical physiological roles in both heart and epithelial tissues. In heart, Kv7.1 and the accessory subunit KCNE1 forms the IKs current, which is enhanced by PKA mediated phosphorylation. The observed current increase requires both phosphorylation of Kv7.......1 and the presence of KCNE1. However, PKA also stimulates Kv7.1 currents in epithelial tissues, such as colon, where the channel does not co-assemble with KCNE1. Here, we demonstrate that PKA activity significantly impacts the subcellular localization of Kv7.1 in Madin Darby Canine Kidney cells. While PKA inhibition...... reduced the fraction of channels at the cell surface, PKA activation increased it. We show that PKA inhibition lead to intracellular accumulation of Kv7.1 in late endosomes/lysosomes. By mass spectroscopy we identified eight phosphorylated residues on Kv7.1, however, none appeared to play a role...

  10. Major Refit for CERN's 400 kV Substation (Part of the new control and protection system for the 18 kV side)

    CERN Document Server

    2001-01-01

    The 400 kV substation on the Prévessin site brings in the electricity that powers CERN's accelerators and the majority of the Laboratory's installations. It was originally built in the 1970s for the SPS, and is one of only five privately owned 400 kV sub-stations in France. Three of the others belong to the national railway company, SNCF, supplying the Paris-Marseilles TGV line, the other is at the Cadarache research centre near mouth of the Rhone. After nearly thirty years of service, CERN's substation has just undergone a complete overhaul.

  11. Regulation of Kv1.4 potassium channels by PKC and AMPK kinases

    DEFF Research Database (Denmark)

    Andersen, Martin Nybo; Skibsbye, Lasse; Saljic, Arnela

    2018-01-01

    around the ubiquitin ligase Nedd4-2. In the present study we examined whether Kv1.4, constituting the cardiac Ito,s current, is subject to similar regulation. In the epithelial Madin-Darby Canine Kidney (MDCK) cell line, which constitutes a highly reproducible model system for addressing membrane...... targeting, we find, by confocal microscopy, that Kv1.4 cell surface expression is downregulated by activation of protein kinase C (PKC) and AMP-activated protein kinase (AMPK). In contrast, manipulating the activities of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) and serum and glucocorticoid......-regulated kinase 1 (SGK1) were without effect on channel localization. The PKC and AMPK-mediated downregulation of Kv1.4 membrane surface localization was confirmed by two-electrode voltage clamp in Xenopus laevis oocytes, where pharmacological activation of PKC and AMPK reduced Kv1.4 current levels. We further...

  12. Downregulation of Kv7.4 channel activity in primary and secondary hypertension

    DEFF Research Database (Denmark)

    Jepps, Thomas Andrew; Chadha, Preet S; Davis, Alison J

    2011-01-01

    Voltage-gated potassium (K(+)) channels encoded by KCNQ genes (Kv7 channels) have been identified in various rodent and human blood vessels as key regulators of vascular tone; however, nothing is known about the functional impact of these channels in vascular disease. We ascertained the effect of...... structurally different activators of Kv7.2 through Kv7.5 channels (BMS-204352, S-1, and retigabine) on blood vessels from normotensive and hypertensive animals.......Voltage-gated potassium (K(+)) channels encoded by KCNQ genes (Kv7 channels) have been identified in various rodent and human blood vessels as key regulators of vascular tone; however, nothing is known about the functional impact of these channels in vascular disease. We ascertained the effect of 3...

  13. Kv7.1 surface expression is regulated by epithelial cell polarization

    DEFF Research Database (Denmark)

    Andersen, Martin N; Olesen, Søren-Peter; Rasmussen, Hanne Borger

    2011-01-01

    The potassium channel K(V)7.1 is expressed in the heart where it contributes to the repolarization of the cardiac action potential. In addition, K(V)7.1 is expressed in epithelial tissues where it plays a role in salt and water transport. Mutations in the kcnq1 gene can lead to long QT syndrome...... and deafness, and several mutations have been described as trafficking mutations. To learn more about the basic mechanisms that regulate K(V)7.1 surface expression, we have investigated the trafficking of K(V)7.1 during the polarization process of the epithelial cell line Madin-Darby Canine Kidney (MDCK) using...... is regulated by signaling mechanisms involved in epithelial cell polarization in particular signaling cascades involving protein kinase C and PI3K....

  14. A comparison of kV and MV imaging in head and neck image guided radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Devereux, B. [Radiation Oncology Queensland, 280 North St, Toowoomba 4350 (Australia)], E-mail: beth.devereux@roq.net.au; Frantzis, J.; Sisson, T.; Jones, M.; Martin, J.; Middleton, M. [Radiation Oncology Queensland, 280 North St, Toowoomba 4350 (Australia)

    2010-02-15

    Purpose: To compare and assess kV and MV imaging modalities and their role in image guided radiotherapy (IGRT) for head and neck cancer patients. Method: Twelve patients receiving radical radiotherapy to the head and neck were analysed in this study. Six patients undertook MV daily online intervention and a further six patients undertook kV daily online intervention. Pre-intervention field placement data were collected from three separate observers' image match analysis for each patient. The radiotherapy collective involved in the daily online image match analysis formed the fourth observer in the study. The primary end point was to establish the difference in inter- and intra-observer variance between kV and MV imaging modalities. Results: The range of the standard deviations of systematic set-up error for MV imaging calculated was 1.47-2.33 mm (MV) and 1.61-1.64 mm (kV) for the right-left (RL), 2.10-2.17 mm (MV) and 1.53-1.84 mm (kV) for the cranio-caudal (CC) and 1.43-1.63 mm (MV) and 1.02-1.11 mm (kV) for the anterior-posterior (AP). The mean inter-observer variance was 0.21 mm (MV) and 0.41 mm (kV) for the RL, 0.53 mm (MV) and 0.55 mm (kV) for the CC and 0.23 mm (MV) and 0.16 mm (kV) for the AP direction. Intra-observer mean variance was in the order of 0.60 mm (MV) and 0.16 mm (kV) for the RL, 1.41 mm (MV) and 0.05 mm (kV) for the CC and 1.41 mm (MV) and 0.08 mm (kV) for the AP. Discussion: The data in this study suggest both inter- and intra-observer consistency across kV and MV imaging modalities were comparable. However, it is felt that the improved clarity and quality of kV imaging allows all observers to analyse images in a consistent manner, identifying and acting on potential field placement moves. Conclusion: The introduction of kV imaging has maintained the high levels of inter- and intra-observer consistency achieved with MV imaging. This in turn further enables positive verification outcomes and supports the implementation of potential

  15. The development of a 200 kV monochromated field emission electron source

    Energy Technology Data Exchange (ETDEWEB)

    Mukai, Masaki, E-mail: mmukai@jeol.co.jp [JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558 (Japan); Kim, Judy S. [University of Oxford, Department of Materials, Parks Road, Oxford, OX1 3PH (United Kingdom); Omoto, Kazuya; Sawada, Hidetaka; Kimura, Atsushi; Ikeda, Akihiro; Zhou, Jun; Kaneyama, Toshikatsu [JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558 (Japan); Young, Neil P.; Warner, Jamie H.; Nellist, Peter D.; Kirkland, Angus I. [University of Oxford, Department of Materials, Parks Road, Oxford, OX1 3PH (United Kingdom)

    2014-05-01

    We report the development of a monochromator for an intermediate-voltage aberration-corrected electron microscope suitable for operation in both STEM and TEM imaging modes. The monochromator consists of two Wien filters with a variable energy selecting slit located between them and is located prior to the accelerator. The second filter cancels the energy dispersion produced by the first filter and after energy selection forms a round monochromated, achromatic probe at the specimen plane. The ultimate achievable energy resolution has been measured as 36 meV at 200 kV and 26 meV at 80 kV. High-resolution Annular Dark Field STEM images recorded using a monochromated probe resolve Si–Si spacings of 135.8 pm using energy spreads of 218 meV at 200 kV and 217 meV at 80 kV respectively. In TEM mode an improvement in non-linear spatial resolution to 64 pm due to the reduction in the effects of partial temporal coherence has been demonstrated using broad beam illumination with an energy spread of 134 meV at 200 kV. - Highlights: • Monochromator for 200 kV aberration corrected TEM and STEM was developed. • Monochromator produces monochromated and achromatic probe at specimen plane. • Ultimate energy resolution was measured to be 36 meV at 200 kV and 26 meV at 80 kV. • Atomic resolution STEM images were recorded using monochromated electron probe. • Improvements of TEM resolution were confirmed using monochromated illumination.

  16. Effects of the small molecule HERG activator NS1643 on Kv11.3 channels.

    Directory of Open Access Journals (Sweden)

    Arne Bilet

    Full Text Available NS1643 is one of the small molecule HERG (Kv11.1 channel activators and has also been found to increase erg2 (Kv11.2 currents. We now investigated whether NS1643 is also able to act as an activator of Kv11.3 (erg3 channels expressed in CHO cells. Activation of rat Kv11.3 current occurred in a dose-dependent manner and maximal current increasing effects were obtained with 10 µM NS1643. At this concentration, steady-state outward current increased by about 80% and the current increase was associated with a significant shift in the voltage dependence of activation to more negative potentials by about 15 mV. In addition, activation kinetics were accelerated, whereas deactivation was slowed. There was no significant effect on the kinetics of inactivation and recovery from inactivation. The strong current-activating agonistic effect of NS1643 did not result from a shift in the voltage dependence of Kv11.3 channel inactivation and was independent from external Na(+ or Ca(2+. At the higher concentration of 20 µM, NS1643 induced clearly less current increase. The left shift in the voltage dependence of activation reversed and the voltage sensitivity of activation dramatically decreased along with a slowing of Kv11.3 channel activation. These data show that, in comparison to other Kv11 family members, NS1643 exerts distinct effects on Kv11.3 channels with especially pronounced partial antagonistic effects at higher concentration.

  17. The development of a 200 kV monochromated field emission electron source

    International Nuclear Information System (INIS)

    Mukai, Masaki; Kim, Judy S.; Omoto, Kazuya; Sawada, Hidetaka; Kimura, Atsushi; Ikeda, Akihiro; Zhou, Jun; Kaneyama, Toshikatsu; Young, Neil P.; Warner, Jamie H.; Nellist, Peter D.; Kirkland, Angus I.

    2014-01-01

    We report the development of a monochromator for an intermediate-voltage aberration-corrected electron microscope suitable for operation in both STEM and TEM imaging modes. The monochromator consists of two Wien filters with a variable energy selecting slit located between them and is located prior to the accelerator. The second filter cancels the energy dispersion produced by the first filter and after energy selection forms a round monochromated, achromatic probe at the specimen plane. The ultimate achievable energy resolution has been measured as 36 meV at 200 kV and 26 meV at 80 kV. High-resolution Annular Dark Field STEM images recorded using a monochromated probe resolve Si–Si spacings of 135.8 pm using energy spreads of 218 meV at 200 kV and 217 meV at 80 kV respectively. In TEM mode an improvement in non-linear spatial resolution to 64 pm due to the reduction in the effects of partial temporal coherence has been demonstrated using broad beam illumination with an energy spread of 134 meV at 200 kV. - Highlights: • Monochromator for 200 kV aberration corrected TEM and STEM was developed. • Monochromator produces monochromated and achromatic probe at specimen plane. • Ultimate energy resolution was measured to be 36 meV at 200 kV and 26 meV at 80 kV. • Atomic resolution STEM images were recorded using monochromated electron probe. • Improvements of TEM resolution were confirmed using monochromated illumination

  18. 40-kV, 25-ms neutral-beam power supply for TMX

    International Nuclear Information System (INIS)

    Leavitt, G.A.

    1977-01-01

    Modifications are described to upgrade the neutral-beam power supply for the TMX from 40 kV, 10 ms to 40 kV, 25 ms. The redesign of the accel and suppressor power supplies to achieve separation of the high-voltage and control sections, operation of the arc pulse lines in series, operation of the arc pulse lines in a noisy environment with SCR trigger and crowbar, and modifications to the electrolytic storage banks are discussed

  19. Analisa Penggunaan Recloser untuk Pengaman Arus Lebih pada Jaringan Distribusi 20 Kv Gardu Induk Garuda Sakti

    OpenAIRE

    Putra, Ario; Firdaus, Firdaus

    2017-01-01

    PT.PLN: 20 kV network substations Garuda Sakti, frequently interference, one of interferences is the short-circuit current. To install equipment to include Recloser. This paper discuss the analysisof the use Recloser on distribution network 20 kV, this paper also be simulated using the software ETAP 12.6 which will feature some of the parameters for comparison of calculations and data thatalready exists in PLN, with two parameters, short circuit and coordination Recloser with overcurrent rela...

  20. Distinct molecular features of different macroscopic subtypes of colorectal neoplasms.

    Directory of Open Access Journals (Sweden)

    Kenichi Konda

    Full Text Available Colorectal adenoma develops into cancer with the accumulation of genetic and epigenetic changes. We studied the underlying molecular and clinicopathological features to better understand the heterogeneity of colorectal neoplasms (CRNs.We evaluated both genetic (mutations of KRAS, BRAF, TP53, and PIK3CA, and microsatellite instability [MSI] and epigenetic (methylation status of nine genes or sequences, including the CpG island methylator phenotype [CIMP] markers alterations in 158 CRNs including 56 polypoid neoplasms (PNs, 25 granular type laterally spreading tumors (LST-Gs, 48 non-granular type LSTs (LST-NGs, 19 depressed neoplasms (DNs and 10 small flat-elevated neoplasms (S-FNs on the basis of macroscopic appearance.S-FNs showed few molecular changes except SFRP1 methylation. Significant differences in the frequency of KRAS mutations were observed among subtypes (68% for LST-Gs, 36% for PNs, 16% for DNs and 6% for LST-NGs (P<0.001. By contrast, the frequency of TP53 mutation was higher in DNs than PNs or LST-Gs (32% vs. 5% or 0%, respectively (P<0.007. We also observed significant differences in the frequency of CIMP between LST-Gs and LST-NGs or PNs (32% vs. 6% or 5%, respectively (P<0.005. Moreover, the methylation level of LINE-1 was significantly lower in DNs or LST-Gs than in PNs (58.3% or 60.5% vs. 63.2%, P<0.05. PIK3CA mutations were detected only in LSTs. Finally, multivariate analyses showed that macroscopic morphologies were significantly associated with an increased risk of molecular changes (PN or LST-G for KRAS mutation, odds ratio [OR] 9.11; LST-NG or DN for TP53 mutation, OR 5.30; LST-G for PIK3CA mutation, OR 26.53; LST-G or DN for LINE-1 hypomethylation, OR 3.41.We demonstrated that CRNs could be classified into five macroscopic subtypes according to clinicopathological and molecular differences, suggesting that different mechanisms are involved in the pathogenesis of colorectal tumorigenesis.

  1. Regulation of KV channel voltage-dependent activation by transmembrane β subunits

    Directory of Open Access Journals (Sweden)

    Xiaohui eSun

    2012-04-01

    Full Text Available Voltage-activated K+ (KV channels are important for shaping action potentials and maintaining resting membrane potential in excitable cells. KV channels contain a central pore-gate domain (PGD surrounded by four voltage-sensing domains (VSD. The VSDs will change conformation in response to alterations of the membrane potential thereby inducing the opening of the PGD. Many KV channels are heteromeric protein complexes containing auxiliary β subunits. These β subunits modulate channel expression and activity to increase functional diversity and render tissue specific phenotypes. This review focuses on the KV β subunits that contain transmembrane (TM segments including the KCNE family and the β subunits of large conductance, Ca2+- and voltage-activated K+ (BK channels. These TM β subunits affect the voltage-dependent activation of KV α subunits. Experimental and computational studies have described the structural location of these β subunits in the channel complexes and the biophysical effects on VSD activation, PGD opening and VSD-PGD coupling. These results reveal some common characteristics and mechanistic insights into KV channel modulation by TM β subunits.

  2. Diagnosis of bladder tumours in patients with macroscopic haematuria

    DEFF Research Database (Denmark)

    Gandrup, Karen L; Løgager, Vibeke B; Bretlau, Thomas

    2015-01-01

    patients underwent CTU, MRU and flexible cystoscopy. Two uroradiologists individually reviewed the images without any clinical information, using a questionnaire. Patient records and pathology reports were also reviewed. RESULTS: At flexible cystoscopy, MRU and CTU, 32, 19 and 15 bladder lesions were...... identified, respectively. Histopathology showed that 13 of the 29 biopsied lesions were transitional cell carcinomas. Compared with the histopathology, the sensitivity and specificity for detection of tumours by CTU and MRU were 61.5% and 94.9%, and 79.9% and 93.4%, respectively. False-positive detection...... of bladder tumours, compared with histopathology, was reported in seven CTUs and nine MRUs, whereas the number of false-negative findings was five for CTUs and three for MRUs. CONCLUSIONS: Split-bolus CTU or MRU cannot replace cystoscopy in cases of macroscopic haematuria. MRU has a higher sensitivity than...

  3. Polynomial parameterized representation of macroscopic cross section for PWR reactor

    International Nuclear Information System (INIS)

    Fiel, Joao Claudio B.

    2015-01-01

    The purpose of this work is to describe, by means of Tchebychev polynomial, a parameterized representation of the homogenized macroscopic cross section for PWR fuel element as a function of soluble boron concentration, moderator temperature, fuel temperature, moderator density and 235 U 92 enrichment. Analyzed cross sections are: fission, scattering, total, transport, absorption and capture. This parameterization enables a quick and easy determination of the problem-dependent cross-sections to be used in few groups calculations. The methodology presented here will enable to provide cross-sections values to perform PWR core calculations without the need to generate them based on computer code calculations using standard steps. The results obtained by parameterized cross-sections functions, when compared with the cross-section generated by SCALE code calculations, or when compared with K inf , generated by MCNPX code calculations, show a difference of less than 0.7 percent. (author)

  4. Macroscopic quantum electrodynamics of high-Q cavities

    Energy Technology Data Exchange (ETDEWEB)

    Khanbekyan, Mikayel

    2009-10-27

    In this thesis macroscopic quantum electrodynamics in linear media was applied in order to develop an universally valid quantum theory for the description of the interaction of the electromagnetic field with atomic sources in high-Q cavities. In this theory a complete description of the characteristics of the emitted radiation is given. The theory allows to show the limits of the applicability of the usually applied theory. In order to establish an as possible generally valid theory first the atom-field interaction was studied in the framework of macroscopic quantum electrodynamics in dispersive and absorptive media. In order to describe the electromagnetic field from Maxwell's equations was started, whereby the noise-current densities, which are connected with the absorption of the medium, were included. The solution of these equations expresses the electromagnetic field variables by the noise-current densities by means of Green's tensor of the macroscopic Maxwell equations. The explicit quantization is performed by means of the noise-current densities, whereby a diagonal Hamiltonian is introduced, which then guarantees the time development according to Maxwell's equation and the fulfillment of the fundamental simultaneous commutation relations of the field variables. In the case of the interaction of the medium-supported field with atoms the Hamiltonian must be extended by atom-field interactions energies, whereby the canonical coupling schemes of the minimal or multipolar coupling can be used. The dieelectric properties of the material bodies as well as their shape are coded in the Green tensor of the macroscopic Maxwell equations. As preparing step first the Green tensor was specified in order to derive three-dimensional input-output relations for the electromagnetic field operators on a plane multilayer structure. Such a general dewscription of the electromagnetic field allows the inclusion both of dispersion and absorption of the media and the

  5. Macroscopic Modeling of Transport Phenomena in Direct Methanol Fuel Cells

    DEFF Research Database (Denmark)

    Olesen, Anders Christian

    An increasing need for energy efficiency and high energy density has sparked a growing interest in direct methanol fuel cells for portable power applications. This type of fuel cell directly generates electricity from a fuel mixture consisting of methanol and water. Although this technology...... surpasses batteries in important areas, fundamental research is still required to improve durability and performance. Particularly the transport of methanol and water within the cell structure is difficult to study in-situ. A demand therefore exist for the fundamental development of mathematical models...... for studying their transport. In this PhD dissertation the macroscopic transport phenomena governing direct methanol fuel cell operation are analyzed, discussed and modeled using the two-fluid approach in the computational fluid dynamics framework of CFX 14. The overall objective of this work is to extend...

  6. Macroscopic Floquet topological crystalline steel and superconductor pump

    Science.gov (United States)

    Rossi, Anna M. E. B.; Bugase, Jonas; Fischer, Thomas M.

    2017-08-01

    The transport of a macroscopic steel sphere and a superconducting sphere on top of two-dimensional periodic magnetic patterns is studied experimentally and compared with the theory and with experiments on topological transport of magnetic colloids. Transport of the steel and superconducting sphere is achieved by moving an external permanent magnet on a closed loop around the two-dimensional crystal. The transport is topological, i.e., the spheres are transported by a primitive unit vector of the lattice when the external magnet loop winds around specific directions. We experimentally determine the set of directions the loops must enclose for nontrivial transport of the spheres into various directions. We show that the loops can be used to sort steel and superconducting spheres. We show that the topological transport is robust with respect to the scale of the system and therefore speculate on its down scalability to the molecular scale.

  7. Generation of macroscopic singlet states in atomic ensembles

    Science.gov (United States)

    Tóth, Géza; Mitchell, Morgan W.

    2010-05-01

    We study squeezing of the spin uncertainties by quantum non-demolition (QND) measurement in non-polarized spin ensembles. Unlike the case of polarized ensembles, the QND measurements can be performed with negligible back-action, which allows, in principle, perfect spin squeezing as quantified by Tóth et al (2007 Phys. Rev. Lett. 99 250405). The generated spin states approach many-body singlet states and contain a macroscopic number of entangled particles even when individual spin is large. We introduce the Gaussian treatment of unpolarized spin states and use it to estimate the achievable spin squeezing for realistic experimental parameters. Our proposal might have applications for magnetometry with a high spatial resolution or quantum memories storing information in decoherence free subspaces.

  8. Fault detection by surface seismic scanning tunneling macroscope: Field test

    KAUST Repository

    Hanafy, Sherif M.

    2014-08-05

    The seismic scanning tunneling macroscope (SSTM) is proposed for detecting the presence of near-surface impedance anomalies and faults. Results with synthetic data are consistent with theory in that scatterers closer to the surface provide brighter SSTM profiles than those that are deeper. The SSTM profiles show superresolution detection if the scatterers are in the near-field region of the recording line. The field data tests near Gulf of Aqaba, Haql, KSA clearly show the presence of the observable fault scarp, and identify the subsurface presence of the hidden faults indicated in the tomograms. Superresolution detection of the fault is achieved, even when the 35 Hz data are lowpass filtered to the 5-10 Hz band.

  9. Macroscopic chirality of a liquid crystal from nonchiral molecules

    International Nuclear Information System (INIS)

    Jakli, A.; Nair, G. G.; Lee, C. K.; Sun, R.; Chien, L. C.

    2001-01-01

    The transfer of chirality from nonchiral polymer networks to the racemic B2 phase of nonchiral banana-shaped molecules is demonstrated. This corresponds to the transfer of chirality from an achiral material to another achiral material. There are two levels of chirality transfers. (a) On a microscopic level the presence of a polymer network (chiral or nonchiral) favors a chiral state over a thermodynamically stable racemic state due to the inversion symmetry breaking at the polymer-liquid crystal interfaces. (b) A macroscopically chiral (enantimerically enriched) sample can be produced if the polymer network has a helical structure, and/or contains chemically chiral groups. The chirality transfer can be locally suppressed by exposing the liquid crystal to a strong electric field treatment

  10. Fault detection by surface seismic scanning tunneling macroscope: Field test

    KAUST Repository

    Hanafy, Sherif M.; Schuster, Gerard T.

    2014-01-01

    The seismic scanning tunneling macroscope (SSTM) is proposed for detecting the presence of near-surface impedance anomalies and faults. Results with synthetic data are consistent with theory in that scatterers closer to the surface provide brighter SSTM profiles than those that are deeper. The SSTM profiles show superresolution detection if the scatterers are in the near-field region of the recording line. The field data tests near Gulf of Aqaba, Haql, KSA clearly show the presence of the observable fault scarp, and identify the subsurface presence of the hidden faults indicated in the tomograms. Superresolution detection of the fault is achieved, even when the 35 Hz data are lowpass filtered to the 5-10 Hz band.

  11. The N-salicylidene aniline mesogen: Microscopic and macroscopic properties

    International Nuclear Information System (INIS)

    Nesrullazade, A.

    2004-01-01

    The vast majority of compounds exhibiting Iiquid crystalline phases may be regarded as having a rigid molecular central group with one or two flexible terminal alkyl or alkyloxy chains. The N-saIicyIidene anilines are very interesting and important materials both from fundamental and application points of view. These materials are on the one hand the ligands used to obtain metal containing complexes and on the other hand they are materials having the thermotropic mesomorphism. In this work we present investigations of microscopic and macroscopic properties of the 4-(Octyloxy)-N-(4-hexylphenyl)-2-hydrobenzaIimine (8SA) compound which was synthesized by our group. The 8SA compound shows the smectic C and nematic mesophases. These mesophases are enantiotropic and display specific confocal and schlieren textures, respectively. Thermotropic and thermodynamical properties of the straight and reverse phase transitions between smectic C and nematic mesophases and between nematic mesophase and isotropic liquid have been investigated

  12. Non-Poissonian photon statistics from macroscopic photon cutting materials.

    Science.gov (United States)

    de Jong, Mathijs; Meijerink, Andries; Rabouw, Freddy T

    2017-05-24

    In optical materials energy is usually extracted only from the lowest excited state, resulting in fundamental energy-efficiency limits such as the Shockley-Queisser limit for single-junction solar cells. Photon-cutting materials provide a way around such limits by absorbing high-energy photons and 'cutting' them into multiple low-energy excitations that can subsequently be extracted. The occurrence of photon cutting or quantum cutting has been demonstrated in a variety of materials, including semiconductor quantum dots, lanthanides and organic dyes. Here we show that photon cutting results in bunched photon emission on the timescale of the excited-state lifetime, even when observing a macroscopic number of optical centres. Our theoretical derivation matches well with experimental data on NaLaF 4 :Pr 3+ , a material that can cut deep-ultraviolet photons into two visible photons. This signature of photon cutting can be used to identify and characterize new photon-cutting materials unambiguously.

  13. Modeling Macroscopic Shape Distortions during Sintering of Multi-layers

    DEFF Research Database (Denmark)

    Tadesse Molla, Tesfaye

    as to help achieve defect free multi-layer components. The initial thickness ratio between the layers making the multi-layer has also significant effect on the extent of camber evolution depending on the material systems. During sintering of tubular bi-layer structures, tangential (hoop) stresses are very...... large compared to radial stresses. The maximum value of hoop stress, which can generate processing defects such as cracks and coating peel-offs, occurs at the beginning of the sintering cycle. Unlike most of the models defining material properties based on porosity and grain size only, the multi...... (firing). However, unintended features like shape instabilities of samples, cracks or delamination of layers may arise during sintering of multi-layer composites. Among these defects, macroscopic shape distortions in the samples can cause problems in the assembly or performance of the final component...

  14. Averaging problem in general relativity, macroscopic gravity and using Einstein's equations in cosmology.

    Science.gov (United States)

    Zalaletdinov, R. M.

    1998-04-01

    The averaging problem in general relativity is briefly discussed. A new setting of the problem as that of macroscopic description of gravitation is proposed. A covariant space-time averaging procedure is described. The structure of the geometry of macroscopic space-time, which follows from averaging Cartan's structure equations, is described and the correlation tensors present in the theory are discussed. The macroscopic field equations (averaged Einstein's equations) derived in the framework of the approach are presented and their structure is analysed. The correspondence principle for macroscopic gravity is formulated and a definition of the stress-energy tensor for the macroscopic gravitational field is proposed. It is shown that the physical meaning of using Einstein's equations with a hydrodynamic stress-energy tensor in looking for cosmological models means neglecting all gravitational field correlations. The system of macroscopic gravity equations to be solved when the correlations are taken into consideration is given and described.

  15. Retigabine, a Kv7.2/Kv7.3-Channel Opener, Attenuates Drug-Induced Seizures in Knock-In Mice Harboring Kcnq2 Mutations.

    Science.gov (United States)

    Ihara, Yukiko; Tomonoh, Yuko; Deshimaru, Masanobu; Zhang, Bo; Uchida, Taku; Ishii, Atsushi; Hirose, Shinichi

    2016-01-01

    The hetero-tetrameric voltage-gated potassium channel Kv7.2/Kv7.3, which is encoded by KCNQ2 and KCNQ3, plays an important role in limiting network excitability in the neonatal brain. Kv7.2/Kv7.3 dysfunction resulting from KCNQ2 mutations predominantly causes self-limited or benign epilepsy in neonates, but also causes early onset epileptic encephalopathy. Retigabine (RTG), a Kv7.2/ Kv7.3-channel opener, seems to be a rational antiepileptic drug for epilepsies caused by KCNQ2 mutations. We therefore evaluated the effects of RTG on seizures in two strains of knock-in mice harboring different Kcnq2 mutations, in comparison to the effects of phenobarbital (PB), which is the first-line antiepileptic drug for seizures in neonates. The subjects were heterozygous knock-in mice (Kcnq2Y284C/+ and Kcnq2A306T/+) bearing the Y284C or A306T Kcnq2 mutation, respectively, and their wild-type (WT) littermates, at 63-100 days of age. Seizures induced by intraperitoneal injection of kainic acid (KA, 12mg/kg) were recorded using a video-electroencephalography (EEG) monitoring system. Effects of RTG on KA-induced seizures of both strains of knock-in mice were assessed using seizure scores from a modified Racine's scale and compared with those of PB. The number and total duration of spike bursts on EEG and behaviors monitored by video recording were also used to evaluate the effects of RTG and PB. Both Kcnq2Y284C/+ and Kcnq2A306T/+ mice showed significantly more KA-induced seizures than WT mice. RTG significantly attenuated KA-induced seizure activities in both Kcnq2Y284C/+ and Kcnq2A306T/+ mice, and more markedly than PB. This is the first reported evidence of RTG ameliorating KA-induced seizures in knock-in mice bearing mutations of Kcnq2, with more marked effects than those observed with PB. RTG or other Kv7.2-channel openers may be considered as first-line antiepileptic treatments for epilepsies resulting from KCNQ2 mutations.

  16. T Cell Subset and Stimulation Strength-Dependent Modulation of T Cell Activation by Kv1.3 Blockers.

    Directory of Open Access Journals (Sweden)

    Wai-Ping Fung-Leung

    Full Text Available Kv1.3 is a voltage-gated potassium channel expressed on T cells that plays an important role in T cell activation. Previous studies have shown that blocking Kv1.3 channels in human T cells during activation results in reduced calcium entry, cytokine production, and proliferation. The aim of the present study was to further explore the effects of Kv1.3 blockers on the response of different human T cell subsets under various stimulation conditions. Our studies show that, unlike the immune suppressor cyclosporine A, the inhibitory effect of Kv1.3 blockers was partial and stimulation strength dependent, with reduced inhibitory efficacy on T cells under strengthened anti-CD3/CD28 stimulations. T cell responses to allergens including house dust mites and ragweed were partially reduced by Kv1.3 blockers. The effect of Kv1.3 inhibition was dependent on T cell subsets, with stronger effects on CCR7- effector memory compared to CCR7+ central memory CD4 T cells. Calcium entry studies also revealed a population of CD4 T cells resistant to Kv1.3 blockade. Activation of CD4 T cells was accompanied with an increase in Kv1.3 currents but Kv1.3 transcripts were found to be reduced, suggesting a posttranscriptional mechanism in the regulation of Kv1.3 activities. In summary, Kv1.3 blockers inhibit T cell activation in a manner that is highly dependent on the T cell identity and stimulation strength, These findings suggest that Kv1.3 blockers inhibit T cells in a unique, conditional manner, further refining our understanding of the therapeutic potential of Kv1.3 blockers.

  17. Immunomodulatory effects of diclofenac in leukocytes through the targeting of Kv1.3 voltage-dependent potassium channels.

    Science.gov (United States)

    Villalonga, Núria; David, Miren; Bielańska, Joanna; González, Teresa; Parra, David; Soler, Concepció; Comes, Núria; Valenzuela, Carmen; Felipe, Antonio

    2010-09-15

    Kv1.3 plays a crucial role in the activation and proliferation of T-lymphocytes and macrophages. While Kv1.3 is responsible for the voltage-dependent potassium current in T-cells, in macrophages this K(+) current is generated by the association of Kv1.3 and Kv1.5. Patients with autoimmune diseases show a high number of effector memory T cells that are characterized by a high expression of Kv1.3 and Kv1.3 antagonists ameliorate autoimmune disorders in vivo. Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) used in patients who suffer from painful autoimmune diseases such as rheumatoid arthritis. In this study, we show that diclofenac impairs immune response via a mechanism that involves Kv1.3. While diclofenac inhibited Kv1.3 expression in activated macrophages and T-lymphocytes, Kv1.5 remained unaffected. Diclofenac also decreased iNOS levels in Raw 264.7 cells, impairing their activation in response to lipopolysaccharide (LPS). LPS-induced macrophage migration and IL-2 production in stimulated Jurkat T-cells were also blocked by pharmacological doses of diclofenac. These effects were mimicked by Margatoxin, a specific Kv1.3 inhibitor, and Charybdotoxin, which blocks both Kv1.3 and Ca(2+)-activated K(+) channels (K(Ca)3.1). Because Kv1.3 is a very good target for autoimmune therapies, the effects of diclofenac on Kv1.3 are of high pharmacological relevance. Copyright 2010 Elsevier Inc. All rights reserved.

  18. High reliability low jitter 80 kV pulse generator

    International Nuclear Information System (INIS)

    Savage, Mark Edward; Stoltzfus, Brian Scott

    2009-01-01

    Switching can be considered to be the essence of pulsed power. Time accurate switch/trigger systems with low inductance are useful in many applications. This article describes a unique switch geometry coupled with a low-inductance capacitive energy store. The system provides a fast-rising high voltage pulse into a low impedance load. It can be challenging to generate high voltage (more than 50 kilovolts) into impedances less than 10 (Omega), from a low voltage control signal with a fast rise time and high temporal accuracy. The required power amplification is large, and is usually accomplished with multiple stages. The multiple stages can adversely affect the temporal accuracy and the reliability of the system. In the present application, a highly reliable and low jitter trigger generator was required for the Z pulsed-power facility [M. E. Savage, L. F. Bennett, D. E. Bliss, W. T. Clark, R. S. Coats,J. M. Elizondo, K. R. LeChien, H. C. Harjes, J. M. Lehr, J. E. Maenchen, D. H. McDaniel, M. F. Pasik, T. D. Pointon, A. C. Owen, D. B. Seidel, D. L. Smith, B. S. Stoltzfus, K.W. Struve, W.A. Stygar, L.K. Warne, and J. R. Woodworth, 2007 IEEE Pulsed Power Conference, Albuquerque, NM (IEEE, Piscataway, NJ, 2007), p. 979]. The large investment in each Z experiment demands low prefire probability and low jitter simultaneously. The system described here is based on a 100 kV DC-charged high-pressure spark gap, triggered with an ultraviolet laser. The system uses a single optical path for simultaneously triggering two parallel switches, allowing lower inductance and electrode erosion with a simple optical system. Performance of the system includes 6 ns output rise time into 5.6 (Omega), 550 ps one-sigma jitter measured from the 5 V trigger to the high voltage output, and misfire probability less than 10 -4 . The design of the system and some key measurements will be shown in the paper. We will discuss the design goals related to high reliability and low jitter. While

  19. Marys Lake 69/115-kV transmission line upgrade and substation expansion projects

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    Western Area Power Administration (Western) and the Platte River Power Authority (Platte River) propose to upgrade portions of the existing electric transmission and substation system that serves the Town of Estes Park, Colorado. The existing transmission lines between the Estes Power Plant Switchyard and the Marys Lake Substation include a 115,000 volt (115-kV) line and 69,000 volt (69-kV) line. Approximately one mile is a double-circuit 115/69-kV line on steel lattice structures, and approximately two miles consists of separate single-circuit 115-kV and a 69-kV lines, constructed on wood H-Frame structures. Both lines were constructed in 1951 by the US Bureau of Reclamation. The existing transmission lines are on rights-of-way (ROW) that vary from 75 feet to 120 feet and are owned by Western. There are 48 landowners adjacent to the existing ROW. All of the houses were built adjacent to the existing ROW after the transmission lines were constructed. Upgrading the existing 69-kV transmission line between the Marys Lake Substation and the Estes Power Plant Switchyard to 115-kV and expanding the Marys Lake Substation was identified as the most effective way in which to improve electric service to Estes Park. The primary purpose and need of the proposed project is to improve the reliability of electric service to the Town of Estes Park. Lack of reliability has been a historical concern, and reliability will always be less than desired until physical improvements are made to the electrical facilities serving Estes Park.

  20. Quality control of a kV cone beam computed tomography imaging system

    International Nuclear Information System (INIS)

    Marguet, M.; Bodez, V.

    2009-01-01

    Purpose: This work presents the introduction of a quality assurance program for the On-Board Imager (O.B.I., Varian) kV cone beam computed tomography (kV C.B.C.T.) system, together with the results of 1 year monthly testing. Materials and methods: Firstly the geometric precision and stability of the equipment and of the associated software were evaluated using the Marker phantom. The coincidence of the accelerator isocenter and the imager isocenter was verified as well as the accuracy of the registration of kV cone beam computed tomography (kV C.B.C.T.) with reference CT images. Then, the kV C.B.C.T. image quality was evaluated using the Catphan 504 phantom and ArtiScan software (Aquilab) for both full-fan (F.F.) and half-fan (H.F.) imaging modes. Results: The kV C.B.C.T. isocenter and image registration with correction of the table position were found to be within a tolerance of 2.0 mm. Concerning the kV C.B.C.T. image quality, image noise and uniformity, the Hounsfield units (HU) stability and linearity, geometric distortion and high contrast resolution were all found to be within the manufacturer's recommendations for both F.F. and H.F. modes. However, the low contrast resolution for the HF mode did not meet the manufacturer's specifications. Conclusion: The quality assurance tests introduced have defined the initial system characteristics and their evolution during a period of 1 year, demonstrating the stability of the O.B.I.. (authors)

  1. Marys Lake 69/115-kV transmission line upgrade and substation expansion projects

    International Nuclear Information System (INIS)

    1996-05-01

    Western Area Power Administration (Western) and the Platte River Power Authority (Platte River) propose to upgrade portions of the existing electric transmission and substation system that serves the Town of Estes Park, Colorado. The existing transmission lines between the Estes Power Plant Switchyard and the Marys Lake Substation include a 115,000 volt (115-kV) line and 69,000 volt (69-kV) line. Approximately one mile is a double-circuit 115/69-kV line on steel lattice structures, and approximately two miles consists of separate single-circuit 115-kV and a 69-kV lines, constructed on wood H-Frame structures. Both lines were constructed in 1951 by the US Bureau of Reclamation. The existing transmission lines are on rights-of-way (ROW) that vary from 75 feet to 120 feet and are owned by Western. There are 48 landowners adjacent to the existing ROW. All of the houses were built adjacent to the existing ROW after the transmission lines were constructed. Upgrading the existing 69-kV transmission line between the Marys Lake Substation and the Estes Power Plant Switchyard to 115-kV and expanding the Marys Lake Substation was identified as the most effective way in which to improve electric service to Estes Park. The primary purpose and need of the proposed project is to improve the reliability of electric service to the Town of Estes Park. Lack of reliability has been a historical concern, and reliability will always be less than desired until physical improvements are made to the electrical facilities serving Estes Park

  2. Trafficking of Kv2.1 Channels to the Axon Initial Segment by a Novel Nonconventional Secretory Pathway

    DEFF Research Database (Denmark)

    Jensen, Camilla Stampe; Watanabe, Shoji; Stas, Jeroen Ingrid

    2017-01-01

    the localization of Kv2.1 in these two different membrane compartments in cultured rat hippocampal neurons of mixed sex. Our data uncover a unique ability of Kv2.1 channels to use two molecularly distinct trafficking pathways to accomplish this. Somatodendritic Kv2.1 channels are targeted by the conventional...... secretory pathway, whereas axonal Kv2.1 channels are targeted by a nonconventional trafficking pathway independent of the Golgi apparatus. We further identified a new AIS trafficking motif in the C-terminus of Kv2.1, and show that putative phosphorylation sites in this region are critical for the restricted.......SIGNIFICANCE STATEMENT Our study uncovered a novel mechanism that targets the Kv2.1 voltage-gated potassium channel to two distinct trafficking pathways and two distinct subcellular destinations: the somatodendritic plasma membrane and that of the axon initial segment. We also identified a distinct motif, including...

  3. Overvoltages transferred from a network of 220 kV to 15.65 kV level of the step-up transformer in HPP 'Bajina Bašta'

    Directory of Open Access Journals (Sweden)

    Vukelja Petar

    2011-01-01

    Full Text Available The paper presents the results of research in lightning surge waves and switching overvoltages transferred from a network of 220 kV to the 15.65 kV level of the step-up transformer in HPP 'Bajina Bašta'. Analysis of survey results lead to conclusion that transferred overvoltages can endanger 15.65 kV transformer windings and stator winding insulation. It was therefore suggested for the protection of the 15.65 kV isolation to install metal oxide surge arresters at a suitable place between the power generator bus bars and earthing.

  4. Voltage Analysis Improvement of 150 kV Transmission Subsystem Using Static Synchronous Compensator (STATCOM)

    Science.gov (United States)

    Akbar, P. A.; Hakim, D. L.; Sucita, T.

    2018-02-01

    In this research, testing improvements to the distribution voltage electricity at 150 kV transmission subsystem Bandung Selatan and New Ujungberung using Flexible AC Transmission System (FACTS) technology. One of them is by doing the control of active and reactive power through the power electronics equipment Static Synchronous Compensator (STATCOM). The subsystem is tested because it has a voltage profile are relatively less well when based on the IEEE / ANSI C.84.1 (142.5 - 157.5 kV). This study was conducted by analyzing the Newton-Raphson power flow on the simulator DigSilent Power Factory 15 to determine the profile of the voltage (V) on the system. Bus which has the lowest voltage to be a reference in the installation of STATCOM. From this research is known that the voltage on the conditions of the existing bus 28, as many as 21-23 still below standard buses (142.5 kV), after the installation is done using STATCOM, voltage on the buses improved by increasing the number of tracks that follow the standard / is in the range 142.5 kV -157.5 kV as many as 23-27 buses or 78.6% - 96%, with the optimum mounting on a bus Rancaekek STATCOM II with a capacity of 300 MVA.

  5. Clofazimine inhibits human Kv1.3 potassium channel by perturbing calcium oscillation in T lymphocytes.

    Directory of Open Access Journals (Sweden)

    Yunzhao R Ren

    Full Text Available The Kv1.3 potassium channel plays an essential role in effector memory T cells and has been implicated in several important autoimmune diseases including multiple sclerosis, psoriasis and type 1 diabetes. A number of potent small molecule inhibitors of Kv1.3 channel have been reported, some of which were found to be effective in various animal models of autoimmune diseases. We report herein the identification of clofazimine, a known anti-mycobacterial drug, as a novel inhibitor of human Kv1.3. Clofazimine was initially identified as an inhibitor of intracellular T cell receptor-mediated signaling leading to the transcriptional activation of human interleukin-2 gene in T cells from a screen of the Johns Hopkins Drug Library. A systematic mechanistic deconvolution revealed that clofazimine selectively blocked the Kv1.3 channel activity, perturbing the oscillation frequency of the calcium-release activated calcium channel, which in turn led to the inhibition of the calcineurin-NFAT signaling pathway. These effects of clofazimine provide the first line of experimental evidence in support of a causal relationship between Kv1.3 and calcium oscillation in human T cells. Furthermore, clofazimine was found to be effective in blocking human T cell-mediated skin graft rejection in an animal model in vivo. Together, these results suggest that clofazimine is a promising immunomodulatory drug candidate for treating a variety of autoimmune disorders.

  6. Identification of a functional interaction between Kv4.3 channels and c-Src tyrosine kinase.

    Science.gov (United States)

    Gomes, Pedro; Saito, Tomoaki; Del Corsso, Cris; Alioua, Abderrahmane; Eghbali, Mansoureh; Toro, Ligia; Stefani, Enrico

    2008-10-01

    Voltage-gated K(+) (Kv) channels are key determinants of cardiac and neuronal excitability. A substantial body of evidence has accumulated in support of a role for Src family tyrosine kinases in the regulation of Kv channels. In this study, we examined the possibility that c-Src tyrosine kinase participates in the modulation of the transient voltage-dependent K(+) channel Kv4.3. Supporting a mechanistic link between Kv4.3 and c-Src, confocal microscopy analysis of HEK293 cells stably transfected with Kv4.3 showed high degree of co-localization of the two proteins at the plasma membrane. Our results further demonstrate an association between Kv4.3 and c-Src by co-immunoprecipitation and GST pull-down assays, this interaction being mediated by the SH2 and SH3 domains of c-Src. Furthermore, we show that Kv4.3 is tyrosine phosphorylated under basal conditions. The functional relevance of the observed interaction between Kv4.3 and c-Src was established in patch-clamp experiments, where application of the Src inhibitor PP2 caused a decrease in Kv4.3 peak current amplitude, but not the inactive structural analogue PP3. Conversely, intracellular application of recombinant c-Src kinase or the protein tyrosine phosphatase inhibitor bpV(phen) increased Kv4.3 peak current amplitude. In conclusion, our findings provide evidence that c-Src-induced Kv4.3 channel activation involves their association in a macromolecular complex and suggest a role for c-Src-Kv4.3 pathway in regulating cardiac and neuronal excitability.

  7. Development of Highly Selective Kv1.3-Blocking Peptides Based on the Sea Anemone Peptide ShK

    Directory of Open Access Journals (Sweden)

    Michael W. Pennington

    2015-01-01

    Full Text Available ShK, from the sea anemone Stichodactyla helianthus, is a 35-residue disulfide-rich peptide that blocks the voltage-gated potassium channel Kv1.3 at ca. 10 pM and the related channel Kv1.1 at ca. 16 pM. We developed an analog of this peptide, ShK-186, which is currently in Phase 1b-2a clinical trials for the treatment of autoimmune diseases such as multiple sclerosis and rheumatoid arthritis. While ShK-186 displays a >100-fold improvement in selectivity for Kv1.3 over Kv1.1 compared with ShK, there is considerable interest in developing peptides with an even greater selectivity ratio. In this report, we describe several variants of ShK that incorporate p-phophono-phenylalanine at the N-terminus coupled with internal substitutions at Gln16 and Met21. In addition, we also explored the combinatorial effects of these internal substitutions with an alanine extension at the C-terminus. Their selectivity was determined by patch-clamp electrophysiology on Kv1.3 and Kv1.1 channels stably expressed in mouse fibroblasts. The peptides with an alanine extension blocked Kv1.3 at low pM concentrations and exhibited up to 2250-fold selectivity for Kv1.3 over Kv1.1. Analogs that incorporates p-phosphono-phenylalanine at the N-terminus blocked Kv1.3 with IC50s in the low pM range and did not affect Kv1.1 at concentrations up to 100 nM, displaying a selectivity enhancement of >10,000-fold for Kv1.3 over Kv1.1. Other potentially important Kv channels such as Kv1.4 and Kv1.6 were only partially blocked at 100 nM concentrations of each of the ShK analogs.

  8. Blockade of the voltage-gated potassium channel Kv1.3 inhibits immune responses in vivo.

    Science.gov (United States)

    Koo, G C; Blake, J T; Talento, A; Nguyen, M; Lin, S; Sirotina, A; Shah, K; Mulvany, K; Hora, D; Cunningham, P; Wunderler, D L; McManus, O B; Slaughter, R; Bugianesi, R; Felix, J; Garcia, M; Williamson, J; Kaczorowski, G; Sigal, N H; Springer, M S; Feeney, W

    1997-06-01

    The voltage activated K+ channel (Kv1.3) has recently been identified as the molecule that sets the resting membrane potential of peripheral human T lymphoid cells. In vitro studies indicate that blockage of Kv1.3 inhibits T cell activation, suggesting that Kv1.3 may be a target for immunosuppression. However, despite the in vitro evidence, there has been no in vivo demonstration that blockade of Kv1.3 will attenuate an immune response. The difficulty is due to species differences, as the channel does not set the membrane potential in rodent peripheral T cells. In this study, we show that the channel is present on peripheral T cells of miniswine. Using the peptidyl Kv1.3 inhibitor, margatoxin, we demonstrate that Kv1.3 also regulates the resting membrane potential, and that blockade of Kv1.3 inhibits, in vivo, both a delayed-type hypersensitivity reaction and an Ab response to an allogeneic challenge. In addition, prolonged Kv1.3 blockade causes reduced thymic cellularity and inhibits the thymic development of T cell subsets. These results provide in vivo evidence that Kv1.3 is a novel target for immunomodulation.

  9. The Seismic Analysis of 800kV Gas Insulated Switchgear (GIS) for the Dangjin Thermal Plant

    Energy Technology Data Exchange (ETDEWEB)

    Shin, I.H.; Song, W.P.; Kweon, K.Y. [Hyosung Corporation (Korea)

    1999-05-01

    800kV GIS (Gas Insulated Switchgear) which was first developed in korea at Dec. 1998 and is going to be installed in the dangjin thermal plant. We checked the stability of 800kV GIS under seismic load. pro-ENGINEER and PATRAN were used for modeling exactly 800kV GIS geometry. The 800kV GIS was modeled as shell elements for the enclosures and beam elements for the conductors and the support insulators. (author). 2 refs., 9 figs., 2 tabs.

  10. Macroscopic objects in quantum mechanics: A combinatorial approach

    International Nuclear Information System (INIS)

    Pitowsky, Itamar

    2004-01-01

    Why do we not see large macroscopic objects in entangled states? There are two ways to approach this question. The first is dynamic. The coupling of a large object to its environment cause any entanglement to decrease considerably. The second approach, which is discussed in this paper, puts the stress on the difficulty of observing a large-scale entanglement. As the number of particles n grows we need an ever more precise knowledge of the state and an ever more carefully designed experiment, in order to recognize entanglement. To develop this point we consider a family of observables, called witnesses, which are designed to detect entanglement. A witness W distinguishes all the separable (unentangled) states from some entangled states. If we normalize the witness W to satisfy tr(Wρ)≤1 for all separable states ρ, then the efficiency of W depends on the size of its maximal eigenvalue in absolute value; that is, its operator norm parallel W parallel . It is known that there are witnesses on the space of n qubits for which parallel W parallel is exponential in n. However, we conjecture that for a large majority of n-qubit witnesses parallel W parallel ≤O(√(n log n)). Thus, in a nonideal measurement, which includes errors, the largest eigenvalue of a typical witness lies below the threshold of detection. We prove this conjecture for the family of extremal witnesses introduced by Werner and Wolf [Phys. Rev. A 64, 032112 (2001)

  11. Feedback Gating Control for Network Based on Macroscopic Fundamental Diagram

    Directory of Open Access Journals (Sweden)

    YangBeibei Ji

    2016-01-01

    Full Text Available Empirical data from Yokohama, Japan, showed that a macroscopic fundamental diagram (MFD of urban traffic provides for different network regions a unimodal low-scatter relationship between network vehicle density and network space-mean flow. This provides new tools for network congestion control. Based on MFD, this paper proposed a feedback gating control policy which can be used to mitigate network congestion by adjusting signal timings of gating intersections. The objective of the feedback gating control model is to maximize the outflow and distribute the allowed inflows properly according to external demand and capacity of each gating intersection. An example network is used to test the performance of proposed feedback gating control model. Two types of background signalization types for the intersections within the test network, fixed-time and actuated control, are considered. The results of extensive simulation validate that the proposed feedback gating control model can get a Pareto improvement since the performance of both gating intersections and the whole network can be improved significantly especially under heavy demand situations. The inflows and outflows can be improved to a higher level, and the delay and queue length at all gating intersections are decreased dramatically.

  12. Communication: On the diffusion tensor in macroscopic theory of cavitation

    Science.gov (United States)

    Shneidman, Vitaly A.

    2017-08-01

    The classical description of nucleation of cavities in a stretched fluid relies on a one-dimensional Fokker-Planck equation (FPE) in the space of their sizes r, with the diffusion coefficient D(r) constructed for all r from macroscopic hydrodynamics and thermodynamics, as shown by Zeldovich. When additional variables (e.g., vapor pressure) are required to describe the state of a bubble, a similar approach to construct a diffusion tensor D ^ generally works only in the direct vicinity of the thermodynamic saddle point corresponding to the critical nucleus. It is shown, nevertheless, that "proper" kinetic variables to describe a cavity can be selected, allowing to introduce D ^ in the entire domain of parameters. In this way, for the first time, complete FPE's are constructed for viscous volatile and inertial fluids. In the former case, the FPE with symmetric D ^ is solved numerically. Alternatively, in the case of an inertial fluid, an equivalent Langevin equation is considered; results are compared with analytics. The suggested approach is quite general and can be applied beyond the cavitation problem.

  13. Macroscopic multigroup constants for accelerator driven system core calculation

    International Nuclear Information System (INIS)

    Heimlich, Adino; Santos, Rubens Souza dos

    2011-01-01

    The high-level wastes stored in facilities above ground or shallow repositories, in close connection with its nuclear power plant, can take almost 106 years before the radiotoxicity became of the order of the background. While the disposal issue is not urgent from a technical viewpoint, it is recognized that extended storage in the facilities is not acceptable since these ones cannot provide sufficient isolation in the long term and neither is it ethical to leave the waste problem to future generations. A technique to diminish this time is to transmute these long-lived elements into short-lived elements. The approach is to use an Accelerator Driven System (ADS), a sub-critical arrangement which uses a Spallation Neutron Source (SNS), after separation the minor actinides and the long-lived fission products (LLFP), to convert them to short-lived isotopes. As an advanced reactor fuel, still today, there is a few data around these type of core systems. In this paper we generate macroscopic multigroup constants for use in calculations of a typical ADS fuel, take into consideration, the ENDF/BVI data file. Four energy groups are chosen to collapse the data from ENDF/B-VI data file by PREPRO code. A typical MOX fuel cell is used to validate the methodology. The results are used to calculate one typical subcritical ADS core. (author)

  14. Gravitational wave echoes from macroscopic quantum gravity effects

    Energy Technology Data Exchange (ETDEWEB)

    Barceló, Carlos [Instituto de Astrofísica de Andalucía (IAA-CSIC),Glorieta de la Astronomía, 18008 Granada (Spain); Carballo-Rubio, Raúl [The Cosmology & Gravity Group and the Laboratory for Quantum Gravity & Strings,Department of Mathematics & Applied Mathematics, University of Cape Town,Private Bag, Rondebosch 7701 (South Africa); Garay, Luis J. [Departamento de Física Teórica II,Universidad Complutense de Madrid, 28040 Madrid (Spain); Instituto de Estructura de la Materia (IEM-CSIC),Serrano 121, 28006 Madrid (Spain)

    2017-05-10

    New theoretical approaches developed in the last years predict that macroscopic quantum gravity effects in black holes should lead to modifications of the gravitational wave signals expected in the framework of classical general relativity, with these modifications being characterized in certain scenarios by the existence of dampened repetitions of the primary signal. Here we use the fact that non-perturbative corrections to the near-horizon external geometry of black holes are necessary for these modifications to exist, in order to classify different proposals and paradigms with respect to this criterion and study in a neat and systematic way their phenomenology. Proposals that lead naturally to the existence of echoes in the late-time ringdown of gravitational wave signals from black hole mergers must share the replacement of black holes by horizonless configurations with a physical surface showing reflective properties in the relevant range of frequencies. On the other hand, proposals or paradigms that restrict quantum gravity effects on the external geometry to be perturbative, such as black hole complementarity or the closely related firewall proposal, do not display echoes. For the sake of completeness we exploit the interplay between the timescales associated with the formation of firewalls and the mechanism behind the existence of echoes in order to conclude that even unconventional distortions of the firewall concept (such as naked firewalls) do not lead to this phenomenon.

  15. Zero time tunneling: macroscopic experiments with virtual particles

    Directory of Open Access Journals (Sweden)

    Nimtz Günter

    2015-01-01

    Full Text Available Feynman introduced virtual particles in his diagrams as intermediate states of an interaction process. They represent necessary intermediate states between observable real states. Such virtual particles were introduced to describe the interaction process between an electron and a positron and for much more complicated interaction processes. Other candidates for virtual particles are evanescent modes in optics and in elastic fields. Evanescent modes have a purely imaginary wave number, they represent the mathematical analogy of the tunneling solutions of the Schrödinger equation. Evanescent modes exist in the forbidden frequency bands of a photonic lattice and in undersized wave guides, for instance. The most prominent example for the occurrence of evanescent modes is the frustrated total internal reflection (FTIR at double prisms. Evanescent modes and tunneling lie outside the bounds of the special theory of relativity. They can cause faster than light (FTL signal velocities. We present examples of the quantum mechanical behavior of evanescent photons and phonons at a macroscopic scale. The evanescent modes of photons are described by virtual particles as predicted by former QED calculations.

  16. The universe as an ultimate macroscopic quantum phenomenon?

    International Nuclear Information System (INIS)

    Hu, Bei-Lok

    2005-01-01

    Full text: We explore two unconventional proposals on the meaning of quantum gravity and the quantum properties of spacetime. The first is an older proposal of mine that general relativity is the hydrodynamic limit of some fundamental theories of the microscopic structure of spacetime and matter, a more specific derivative of the idea of Sakharov. The latter is a more recent thought of mine on the possibility that spacetime is a condensate (Bose or Fermi). These proposals have implications radically different from the conventional views. For the former, spacetime described by a differentiable manifold is regarded as an emergent entity and the metric or connection forms are collective variables valid only at the low energy, long wavelength limit of the micro-theories of spacetime and matter. This view would render irrelevant the traditional efforts to find ways to quantize general relativity, because it would only give us the equivalent of phonon physics, not a theory of electrons or photons, QED. In the second proposal, even without the knowledge of what the 'atom of spacetime' is, the mere thought that spacetime at all energies below the Planck scale, including today's, is quantum rather than classical, has many challenging consequences. We discuss the implications of this view pertaining to issues in gravitation and cosmology, as well as to macroscopic quantum coherence phenomena. (author)

  17. Quantum-limited heat conduction over macroscopic distances

    Science.gov (United States)

    Partanen, Matti; Tan, Kuan Yen; Govenius, Joonas; Lake, Russell E.; Mäkelä, Miika K.; Tanttu, Tuomo; Möttönen, Mikko

    2016-05-01

    The emerging quantum technological apparatuses, such as the quantum computer, call for extreme performance in thermal engineering. Cold distant heat sinks are needed for the quantized electric degrees of freedom owing to the increasing packaging density and heat dissipation. Importantly, quantum mechanics sets a fundamental upper limit for the flow of information and heat, which is quantified by the quantum of thermal conductance. However, the short distance between the heat-exchanging bodies in the previous experiments hinders their applicability in quantum technology. Here, we present experimental observations of quantum-limited heat conduction over macroscopic distances extending to a metre. We achieved this improvement of four orders of magnitude in the distance by utilizing microwave photons travelling in superconducting transmission lines. Thus, it seems that quantum-limited heat conduction has no fundamental distance cutoff. This work establishes the integration of normal-metal components into the framework of circuit quantum electrodynamics, which provides a basis for the superconducting quantum computer. Especially, our results facilitate remote cooling of nanoelectronic devices using faraway in situ-tunable heat sinks. Furthermore, quantum-limited heat conduction is important in contemporary thermodynamics. Here, the long distance may lead to ultimately efficient mesoscopic heat engines with promising practical applications.

  18. Macroscopic local-field effects on photoabsorption processes

    International Nuclear Information System (INIS)

    Ma Xiaoguang; Gong Yubing; Wang Meishan; Wang Dehua

    2008-01-01

    The influence of the local-field effect on the photoabsorption cross sections of the atoms which are embedded in the macroscopic medium has been studied by a set of alternative expressions in detail. Some notes on the validity of some different local-field models used to study the photoabsorption cross sections of atoms in condensed matter have been given for the first time. Our results indicate that the local fields can have substantial and different influence on the photoabsorption cross section of atoms in condensed matter for different models. Clausius-Mossotti model and Onsager model have proved to be more reasonable to describe the local field in gas, liquid, or even some simple solid, while Glauber-Lewenstein model probably is wrong in these conditions except for the ideal gas. A procedure which can avoid the errors introduced by Kramers-Kronig transformation has been implemented in this work. This procedure can guarantee that the theoretical studies on the local field effects will not be influenced by the integral instability of the Kramers-Kronig transformation

  19. Theory and feasibility tests for a seismic scanning tunnelling macroscope

    KAUST Repository

    Schuster, Gerard T.

    2012-09-01

    We propose a seismic scanning tunnelling macroscope (SSTM) that can detect subwavelength scatterers in the near-field of either the source or the receivers. Analytic formulas for the time reverse mirror (TRM) profile associated with a single scatterer model show that the spatial resolution limit to be, unlike the Abbe limit of λ/2, independent of wavelength and linearly proportional to the source-scatterer separation as long as the scatterer is in the near-field region. This means that, as the scatterer approaches the source, imaging of the scatterer with super-resolution can be achieved. Acoustic and elastic simulations support this concept, and a seismic experiment in an Arizona tunnel shows a TRM profile with super-resolution adjacent to the fault location. The SSTM is analogous to the optical scanning tunnelling microscopes having subwavelength resolution. Scaled to seismic frequencies, it is theoretically possible to extract 100 Hz information from 20 Hz data by the imaging of near-field seismic energy.

  20. Three lectures on macroscopic aspects of nuclear dynamics

    International Nuclear Information System (INIS)

    Swiatecki, W.J.

    1979-03-01

    These lectures concentrate on macroscopic aspects of nuclear dynamics, those aspects that come into prominence when the number of nucleons, A, is large, A >> 1. An attempt is made to set up a theory of the dynamics of nuclear shape changes, for small (sub-sonic) collective velocities. To set up the equations of motion one needs three forces: conservative, dissipative, and inertial. The first lecture deals with statics, i.e., it discusses methods of treating the Potential Energy Function of nuclear systems. From the Potential Energy the conservative forces that drive the time evolution of a nuclear configuration can be deduced. The division of the underlying potential energy into Local, Proximity, and Global terms is stressed. The second lecture deals with dynamical aspects, especially with the nuclear Dissipation Function, which describes how dissipative frictional forces oppose the conservative driving forces. The underlying physics is the approximate validity of the Independent-Particle model. This, combined with the Randomization Hypothesis, leads to simple formulas that suggest that dissipative forces may often overshadow the inertial forces. The third lecture outlines the kind of dynamics that results from the balance of these forces, and describes a number of applications to nuclear fission and heavy-ion collisions of this New Dynamics. Particularly simple equations of motion are set up, and some of the consequences are explored. 18 references, 31 figures, 3 tables

  1. Validity of macroscopic concepts for fluids on a microscopic scale

    International Nuclear Information System (INIS)

    Alder, B.J.; Alley, W.E.; Pollock, E.L.

    1981-01-01

    By Fourier decomposition of the appropriate fluctuation it is possible within the regime of linear response to extend the concept of both thermodynamic quantities and transport coefficients to their dependence on both wavelength and frequency. Experimentally these generalized macroscopic properties are accessible through neutron diffraction and, as examples, the dependence of the sound speed on wavelength and the diffusion coefficient on time are discussed. Through the molecular dynamics computer method the dependence of the viscosity on wavelength is calculated and applied with spectacular success to predict the dependence of the friction coefficient on the size of a Brownian particle all the way to atomic dimensions. On the other hand, the dielectric constant continuum concept, as applied to a charge or dipole in a cavity, generally fails to predict even the correct field at large distance from the charge. Avoiding the introduction of a cavity cures that problem, but the generalized dielectric constant fails badly in predicting the field at shorter distances from the charge. (orig.)

  2. Grasping the Second Law of Thermodynamics at University: The Consistency of Macroscopic and Microscopic Explanations

    Science.gov (United States)

    Leinonen, Risto; Asikainen, Mervi A.; Hirvonen, Pekka E.

    2015-01-01

    This study concentrates on evaluating the consistency of upper-division students' use of the second law of thermodynamics at macroscopic and microscopic levels. Data were collected by means of a paper and pencil test (N = 48) focusing on the macroscopic and microscopic features of the second law concerned with heat transfer processes. The data…

  3. Quantum mechanics versus macroscopic realism: Is the flux there when nobody looks

    International Nuclear Information System (INIS)

    Leggett, A.J.; Garg, A.

    1985-01-01

    It is shown that, in the contect of an idealized ''macroscopic quantum coherence'' experiment, the prediction of quantum mechanics are incompattible with the conjunction of two general assimptions which are designated ''macroscopic realism'' and ''noninvasive measurability at the macroscopiclevel.'' The conditions under which quantum mechanics can be tested against these assumptions in a realistic experiment are discussed

  4. 600 kV modulator design for the SLAC Next Linear Collider Test Accelerator

    International Nuclear Information System (INIS)

    Harris, K.; de Lamare, J.; Nesterov, V.; Cassel, R.

    1992-07-01

    Preliminary design for the SLAC Next Linear Collider Test Accelerator (NLCTA) requires a pulse power source to produce a 600 kV, 600 A, 1.4 μs, 0.1% flat top pulse with rise and fall times of approximately 100 ns to power an X-Band klystron with a microperveance of 1.25 at ∼ 100 MW peak RF power. The design goals for the modulator, including those previously listed, are peak modulator pulse power of 340 MW operating at 120 Hz. A three-stage darlington pulse-forming network, which produces a >100 kV, 1.4 μs pulse, is coupled to the klystron load through a 6:1 pulse transformer. Careful consideration of the transformer leakage inductance, klystron capacitance, system layout, and component choice is necessary to produce the very fast rise and fall times at 600 kV operating continuously at 120 Hz

  5. 735 kV air-blast circuit breakers for Hydro Quebec

    Energy Technology Data Exchange (ETDEWEB)

    Lindstrom, I

    1966-01-01

    In 1962 the Quebec Hydro-Electric Commission started the development of aproject for utilizing water power in Manicouagan and Outardes, two rivers some 350 miles northeast of the city of Montreal on the left bank of the St. Lawrence estuary. The project involved the transmission of power at 735 kV ac from Manicouagan and Outardes to the heavy and growing load centers of Quebec and Montreal. The total amount of energy to be transmitted in the final stage is about 6,000 MW. The project involved the need of considerable quantities of apparatus for 735 kV, such as transformers, reactors, lightning arrestors, circuit-breakers, and disconnectors. Since the supply of the major part of the 735 kV circuit-breakers, altogether 14 three-pole units, was awarded to ASEA in Sweden, a short presentation of these airblast circuit-breakers is presented.

  6. Field Demonstration of a 24-kV Superconducting Cable at Detroit Edison

    International Nuclear Information System (INIS)

    Kelley, Nathan; Corsaro, Pietro

    2004-01-01

    Customer acceptance of high temperature superconducting (HTS) cable technology requires a substantial field demonstration illustrating both the system's technical capabilities and its suitability for installation and operation within the utility environment. In this project, the world's first underground installation of an HTS cable using existing ductwork, a 120 meter demonstration cable circuit was designed and installed between the 24 kV bus distribution bus and a 120 kV-24 kV transformer at Detroit Edison's Frisbie substation. The system incorporated cables, accessories, a refrigeration system, and control instrumentation. Although the system was never put in operation because of problems with leaks in the cryostat, the project significantly advanced the state-of-the-art in the design and implementation of Warm Dielectric cable systems in substation applications. Lessons learned in this project are already being incorporated in several ongoing demonstration projects

  7. Rearrangement of potassium ions and Kv1.1/Kv1.2 potassium channels in regenerating axons following end-to-end neurorrhaphy: ionic images from TOF-SIMS.

    Science.gov (United States)

    Liu, Chiung-Hui; Chang, Hung-Ming; Wu, Tsung-Huan; Chen, Li-You; Yang, Yin-Shuo; Tseng, To-Jung; Liao, Wen-Chieh

    2017-10-01

    The voltage-gated potassium channels Kv1.1 and Kv1.2 that cluster at juxtaparanodal (JXP) regions are essential in the regulation of nerve excitability and play a critical role in axonal conduction. When demyelination occurs, Kv1.1/Kv1.2 activity increases, suppressing the membrane potential nearly to the equilibrium potential of K + , which results in an axonal conduction blockade. The recovery of K + -dependent communication signals and proper clustering of Kv1.1/Kv1.2 channels at JXP regions may directly reflect nerve regeneration following peripheral nerve injury. However, little is known about potassium channel expression and its relationship with the dynamic potassium ion distribution at the node of Ranvier during the regenerative process of peripheral nerve injury (PNI). In the present study, end-to-end neurorrhaphy (EEN) was performed using an in vivo model of PNI. The distribution of K + at regenerating axons following EEN was detected by time-of-flight secondary-ion mass spectrometry. The specific localization and expression of Kv1.1/Kv1.2 channels were examined by confocal microscopy and western blotting. Our data showed that the re-establishment of K + distribution and intensity was correlated with the functional recovery of compound muscle action potential morphology in EEN rats. Furthermore, the re-clustering of Kv1.1/1.2 channels 1 and 3 months after EEN at the nodal region of the regenerating nerve corresponded to changes in the K + distribution. This study provided direct evidence of K + distribution in regenerating axons for the first time. We proposed that the Kv1.1/Kv1.2 channels re-clustered at the JXP regions of regenerating axons are essential for modulating the proper patterns of K + distribution in axons for maintaining membrane potential stability after EEN.

  8. In vitro measurement of CT density and estimation of stenosis related to coronary soft plaque at 100 kV and 120 kV on ECG-triggered scan

    Energy Technology Data Exchange (ETDEWEB)

    Horiguchi, Jun, E-mail: horiguch@hiroshima-u.ac.jp [Department of Clinical Radiology, Hiroshima University Hospital, 1-2-3, Kasumi-cho, Minami-ku, Hiroshima 734-8551 (Japan); Fujioka, Chikako, E-mail: fujioka@hiroshima-u.ac.jp [Department of Clinical Radiology, Hiroshima University Hospital, 1-2-3, Kasumi-cho, Minami-ku, Hiroshima 734-8551 (Japan); Kiguchi, Masao, E-mail: kiguchi@hiroshima-u.ac.jp [Department of Clinical Radiology, Hiroshima University Hospital, 1-2-3, Kasumi-cho, Minami-ku, Hiroshima 734-8551 (Japan); Yamamoto, Hideya, E-mail: hideyayama@hiroshima-u.ac.jp [Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences and Hiroshima University Hospital, 1-2-3, Kasumi-cho, Minami-ku, Hiroshima 734-8551 (Japan); Shen, Yun, E-mail: Yuna.Shen@ge.com [CT Lab of Great China, GE Healthcare, L12 and L15, Office Tower, Langham Place, 8 Argyle Street, Mongkok Kowloon (Hong Kong); Kihara, Yasuki, E-mail: ykihara@hiroshima-u.ac.jp [Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences and Hiroshima University Hospital, 1-2-3, Kasumi-cho, Minami-ku, Hiroshima 734-8551 (Japan)

    2011-02-15

    Purpose: The purpose of the study was to compare 100 kV and 120 kV prospective electrocardiograph (ECG)-triggered axial coronary 64-detector CT angiography (64-MDCTA) in soft plaque diagnosis. Materials and methods: Coronary artery models (n = 5) with artificial soft plaques (-32 HU to 53 HU at 120 kV) with three stenosis levels (25%, 50% and 75%) on a cardiac phantom (mimicking slim patient's environment) were scanned in heart rates of 55, 60 and 65 beats per minute (bpm). Four kinds of intracoronary enhancement (205 HU, 241 HU, 280 HU and 314 HU) were simulated. The soft plaque density and the measurement error of stenosis (in percentage), evaluated by two independent observers, were compared between 100 kV and 120 kV. The radiation dose was estimated. Results: Interobserver correlation of the measurement was excellent (density; r = 0.95 and stenosis measure; r = 0.97). Neither the density of soft plaque nor the measurement error of stenosis was different between 100 kV and 120 kV (p = 0.22 and 0.08). The estimated radiation doses were 2.0 mSv and 3.3 mSv (in 14 cm coverage) on 100 kV and 120 kV prospective ECG-triggered axial scans, respectively. Conclusion: The 100 kV prospective ECG-triggered coronary MDCTA has comparable performance to 120 kV coronary CTA in terms of soft plaque densitometry and measurement of stenosis, with a reduced effective dose of 2 mSv.

  9. Improvement the Capacity of Cockcroft-Walton High Voltage Source from 300 kV/20 mA to 500 kV/20 mA for Accelerating Voltage of Electron Beam Machine

    International Nuclear Information System (INIS)

    Suprapto; Djasiman

    2002-01-01

    The improvement capacity of Cockcroft-Walton high voltage source from 300 kV/20 mA to 500 kV/mA has been carrying out. To improve the capacity of high voltage source was done by means of increasing the stage number of voltage multiplier from 11 to 18 and its output voltage measuring resistance. Each stage of voltage multiplier consists of 2 capacitors and 2 circuits of high voltage diode. This voltage multiplier is constructed using main components of high voltage capacitor and high voltage diode each of 0.22 μF/50 kV and UF 5408 respectively. To avoid stray discharge and corona it was provided with high voltage electrode and corona ring. The test result indicated that the output voltage obtained from 16 stages was 350 kV according to operating condition of 25 MΩ resistive load and first stage voltage of 28.5 kV with oscillator frequency of 24 Hz. That condition requires anode voltage and current of 5.5 kV and 2.5 A respectively. The no load test for 16 stages indicates 400 kV of output voltage and 28.5 kV first stage voltage. Efficiency of high voltage source was 48 % at 6.75 kW of output power. The expected test of 500 kV with 18 stages of voltage multiplier can not be carried out because of some restrictive of loading system. From the test result can be predicted that the output voltage of 500 kV with 18 stages of voltage multiplier requires 31.2 kV of first stage voltage. Then the expected high voltage source of Cockcroft-Walton is capable as accelerating voltage source for Electron Beam Machine with energy of 500 kV. (author)

  10. Role of stochastic fluctuations in the charge on macroscopic particles in dusty plasmas

    International Nuclear Information System (INIS)

    Vaulina, O.S.; Nefedov, A.P.; Petrov, O.F.; Khrapak, S.A.

    1999-01-01

    The currents which charge a macroscopic particle placed in a plasma consist of discrete charges; hence, the charge can undergo random fluctuations about its equilibrium value. These random fluctuations can be described by a simple model which, if the mechanisms for charging of macroscopic particles are known, makes it possible to determine the dependence of the temporal and amplitude characteristics of the fluctuations on the plasma parameters. This model can be used to study the effect of charge fluctuations on the dynamics of the macroscopic particles. The case of so-called plasma-dust crystals (i.e., highly ordered structures which develop because of strong interactions among macroscopic particles) in laboratory gaseous discharge plasmas is considered as an example. The molecular dynamics method shows that, under certain conditions, random fluctuations in the charge can effectively heat a system of macroscopic particles, thereby impeding the ordering process

  11. Macroscopic erosion of divertor and first wall armour in future tokamaks

    Science.gov (United States)

    Würz, H.; Bazylev, B.; Landman, I.; Pestchanyi, S.; Safronov, V.

    2002-12-01

    Sputtering, evaporation and macroscopic erosion determine the lifetime of the 'in vessel' armour materials CFC, tungsten and beryllium presently under discussion for future tokamaks. For CFC armour macroscopic erosion means brittle destruction and dust formation whereas for metallic armour melt layer erosion by melt motion and droplet splashing. Available results on macroscopic erosion from hot plasma and e-beam simulation experiments and from tokamaks are critically evaluated and a comprehensive discussion of experimental and numerical macroscopic erosion and its extrapolation to future tokamaks is given. Shielding of divertor armour materials by their own vapor exists during plasma disruptions. The evolving plasma shield protects the armour from high heat loads, absorbs the incoming energy and reradiates it volumetrically thus reducing drastically the deposited energy. As a result, vertical target erosion by vaporization turns out to be of the order of a few microns per disruption event and macroscopic erosion becomes the dominant erosion source.

  12. Macroscopic erosion of divertor and first wall armour in future tokamaks

    International Nuclear Information System (INIS)

    Wuerz, H.; Bazylev, B.; Landman, I.; Pestchanyi, S.; Safronov, V.

    2002-01-01

    Sputtering, evaporation and macroscopic erosion determine the lifetime of the 'in vessel' armour materials CFC, tungsten and beryllium presently under discussion for future tokamaks. For CFC armour macroscopic erosion means brittle destruction and dust formation whereas for metallic armour melt layer erosion by melt motion and droplet splashing. Available results on macroscopic erosion from hot plasma and e-beam simulation experiments and from tokamaks are critically evaluated and a comprehensive discussion of experimental and numerical macroscopic erosion and its extrapolation to future tokamaks is given. Shielding of divertor armour materials by their own vapor exists during plasma disruptions. The evolving plasma shield protects the armour from high heat loads, absorbs the incoming energy and reradiates it volumetrically thus reducing drastically the deposited energy. As a result, vertical target erosion by vaporization turns out to be of the order of a few microns per disruption event and macroscopic erosion becomes the dominant erosion source

  13. Evaluation of variation of voltage (kV) absorbed dose in chest CT scans

    International Nuclear Information System (INIS)

    Mendonca, Bruna G.A.; Mourao, Arnaldo P.

    2013-01-01

    Computed tomography (CT) is one of the most important diagnostic techniques images today. The increasing utilization of CT implies a significant increase of population exposure to ionizing radiation. Optimization of practice aims to reduce doses to patients because the image quality is directly related to the diagnosis. You can decrease the amount of dose to the patient, and maintain the quality of the image. There are several parameters that can be manipulated in a CT scan and these parameters can be used to reduce the energy deposited in the patient. Based on this, we analyzed the variation of dose deposited in the lungs, breasts and thyroid, by varying the supply voltage of the tube. Scans of the thorax were performed following the protocol of routine chest with constant and variable current for the same applied voltage. Moreover, a female phantom was used and thermoluminescent dosimeters (TLD-100), model bat, were used to record the specific organ doses. Scans were performed on a GE CT scanner, model 64 Discovery channels. Higher doses were recorded for the voltage of 120 kV with 200 mAs in the lungs (22.46 mGy) and thyroid (32.22 mGy). For scans with automatic mAs, variable between 100 and 440, this same tension contributed to the higher doses. The best examination in terms of the dose that was used with automatic 80 kV mAs, whose lungs and thyroid received lower dose. For the best breast exam was 100 kV. Since the increase in the 80 kV to 100 kV no impact so much the dose deposited in the lungs, it can be concluded that lowering the applied voltage to 100 kV resulted in a reduction in the dose absorbed by the patient. These results can contribute to optimizing scans of the chest computed tomography

  14. Switching Overvoltages in 60 kV reactor compensated cable grid due to resonance after disconnection

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Baldursson, Haukur; Oumarou, Abdoul M.

    2008-01-01

    power could be directly connected to long cables. Switching both cable and reactor together will cause resonance to occur between the cable capacitance and the inductance of the cable during last end disconnection. Similar type of resonance condition is known to have caused switching overvoltages...... on the 400kV grid in Denmark. Therefore it is considered necessary to analyze further whether connecting a reactor directly to 60kV cable can cause switching overvoltages. A model in PSCAD was used to analyze which parameters can cause overvoltage. The switching resonance overvoltage was found to be caused...

  15. Performance of a 100-kV, 78-kJ electric-gun system

    International Nuclear Information System (INIS)

    Chau, H.; Dittbenner, G.; Mikkelsen, K.; Weingart, R.; Froeschner, K.; Lee, R.

    1981-01-01

    A new electric gun system was constructed for use in high-pressure EOS studies. The system is powered by a 100 kV, 15.6 μF capacitor bank. At 100 kV charging voltage the system inductance is 23 nH. This system has driven 0.3 mm-thick Kapton projectiles to > 20 km/s and 0.3 mm Kapton/30 μm Ta projectiles to approx. 10 km/s. Projectile velocity is modeled phenomenlogically by an electrical Gurney model

  16. High power cable with internal water cooling 400 kV

    Energy Technology Data Exchange (ETDEWEB)

    Rasquin, W; Harjes, B

    1982-08-01

    The project was planned for a duration of 4 years. Afterwards it has been extended over 6 years and finally stopped after 3 1/2 years. Therefore, of course results of field tests with an internally cooled 400 kV cable are not available. Nevertheless, this conductor cooled high power cable has been developed to such an extend, that this manufactured cable could withstand type tests according to IEC/VDE recommendations. Even by missing field tests it is obvious that a high power cable for 400 kV is available.

  17. Short-Circuit Degradation of 10-kV 10-A SiC MOSFET

    DEFF Research Database (Denmark)

    Eni, Emanuel-Petre; Beczkowski, Szymon; Munk-Nielsen, Stig

    2017-01-01

    The short-circuit behavior of power devices is highly relevant for converter design and fault protection. In this work, the degradation during short-circuit of a 10 kV 10 A 4H-SiC MOSFET is investigated at 6 kV DC-link voltage. The study aims to present the behavior of the device during short-circuit...... transients as it sustains increasing short-circuit pulses during its life-time. As the short-circuit pulse length increases, degradation of the device can be observed in periodically performed characterizations. The initial degradation seems to be associated with the channel region, and continuous stressing...

  18. Research on Line Patrol Strategy of 110kV Transmission Line after Lightning Strike

    Directory of Open Access Journals (Sweden)

    Li Mingjun

    2016-01-01

    Full Text Available Lightning faults occupy in the majority of instantaneous fault and reclosing can usually be successful, so power supply can be restored without immediate patrol in many cases. Firstly, this paper introduces the lightning fault positioning and identifying method. Then test electrical performance of insulators after lightning strike from 110kV lines. Data shows that lightning strike has little effect on the electric performance of insulator. Finally, illustrating disposal process of the 110 kV transmission line after lightning fault, certifying that the power supply reliability be ensured without line patrol.

  19. Trafficking and intracellular regulation of Kv7.1 potassium channels in the heart

    DEFF Research Database (Denmark)

    Nielsen, Nathalie Hélix

    identified. About 100 of these mutations are located in the N- or the C-terminal parts of the channel. The aim of the present work was to gain a better understanding of the Kv7.1 channel protein function. In the first study we identified a Kv7.1 missense mutation in a German family with Long QT Syndrome......The electrical activity of the heart, measured by application of surface body electrodes and recorded as an electrocardiogram, is the result of a finely tuned balance of ion movement (K+, Na+, Ca2+). The ionic currents collectively constitute the cardiac action potential created in the cell...

  20. AMP-activated protein kinase downregulates Kv7.1 cell surface expression

    DEFF Research Database (Denmark)

    Andersen, Martin N; Krzystanek, Katarzyna; Jespersen, Thomas

    2012-01-01

    in response to polarization of the epithelial Madin-Darby canine kidney (MDCK) cell line and that this was mediated by activation of protein kinase C (PKC). In this study, the pathway downstream of PKC, which leads to internalization of Kv7.1 upon cell polarization, is elucidated. We show by confocal...... microscopy that Kv7.1 is endocytosed upon initiation of the polarization process and sent for degradation by the lysosomal pathway. The internalization could be mimicked by pharmacological activation of the AMP-activated protein kinase (AMPK) using three different AMPK activators. We demonstrate...

  1. A truncated Kv1.1 protein in the brain of the megencephaly mouse: expression and interaction

    Directory of Open Access Journals (Sweden)

    Århem Peter

    2005-11-01

    Full Text Available Abstract Background The megencephaly mouse, mceph/mceph, is epileptic and displays a dramatically increased brain volume and neuronal count. The responsible mutation was recently revealed to be an eleven base pair deletion, leading to a frame shift, in the gene encoding the potassium channel Kv1.1. The predicted MCEPH protein is truncated at amino acid 230 out of 495. Truncated proteins are usually not expressed since nonsense mRNAs are most often degraded. However, high Kv1.1 mRNA levels in mceph/mceph brain indicated that it escaped this control mechanism. Therefore, we hypothesized that the truncated Kv1.1 would be expressed and dysregulate other Kv1 subunits in the mceph/mceph mice. Results We found that the MCEPH protein is expressed in the brain of mceph/mceph mice. MCEPH was found to lack mature (Golgi glycosylation, but to be core glycosylated and trapped in the endoplasmic reticulum (ER. Interactions between MCEPH and other Kv1 subunits were studied in cell culture, Xenopus oocytes and the brain. MCEPH can form tetramers with Kv1.1 in cell culture and has a dominant negative effect on Kv1.2 and Kv1.3 currents in oocytes. However, it does not retain Kv1.2 in the ER of neurons. Conclusion The megencephaly mice express a truncated Kv1.1 in the brain, and constitute a unique tool to study Kv1.1 trafficking relevant for understanding epilepsy, ataxia and pathologic brain overgrowth.

  2. Macroscopic behavior and microscopic magnetic properties of nanocarbon

    Energy Technology Data Exchange (ETDEWEB)

    Lähderanta, E., E-mail: Erkki.Lahderanta@lut.fi [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Ryzhov, V.A. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Petersburg Nuclear Physics Institute, NRC “Kurchatov Institute”, Orlova Coppice, Gatchina, Leningrad province 188300 (Russian Federation); Lashkul, A.V. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Galimov, D.M. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); South Ural State University, 454080 Chelyabinsk (Russian Federation); Titkov, A.N. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); A. F. Ioffe Physico-Technical Institute, 194021 St. Petersburg (Russian Federation); Matveev, V.V. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Saint-Petersburg State University, Saint-Petersburg 198504 (Russian Federation); Mokeev, M.V. [Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg (Russian Federation); Kurbakov, A.I. [Petersburg Nuclear Physics Institute, NRC “Kurchatov Institute”, Orlova Coppice, Gatchina, Leningrad province 188300 (Russian Federation); Lisunov, K.G. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Institute of Applied Physics ASM, Academiei Str., 5, MD 2028 Kishinev (Moldova, Republic of)

    2015-06-01

    Here are presented investigations of powder and glass-like samples containing carbon nanoparticles, not intentionally doped and doped with Ag, Au and Co. The neutron diffraction study reveals an amorphous structure of the samples doped with Au and Co, as well as the magnetic scattering due to a long-range FM order in the Co-doped sample. The composition and molecular structure of the sample doped with Au is clarified with the NMR investigations. The temperature dependence of the magnetization, M (T), exhibits large irreversibility in low fields of B=1–7 mT. M (B) saturates already above 2 T at high temperatures, but deviates from the saturation behavior below ~50 (150 K). Magnetic hysteresis is observed already at 300 K and exhibits a power-law temperature decay of the coercive field, B{sub c} (T). The macroscopic behavior above is typical of an assembly of partially blocked magnetic nanoparticles. The values of the saturation magnetization, M{sub s}, and the blocking temperature, T{sub b}, are obtained as well. However, the hysteresis loop in the Co-doped sample differs from that in other samples, and the values of B{sub c} and M{sub s} are noticeably increased. - Highlights: • We have investigated powder and glassy samples with carbon nanoparticles. • They include an undoped sample and those doped with Ag, Au and Co. • Neutron diffraction study reveals amorphous structure of Au- and Co-doped samples. • Composition and molecular structure of Au-doped sample was investigated with NMR. • Magnetic behavior is typical of an assembly of partially blocked magnetic nanoparticles.

  3. Macroscopic behavior and microscopic magnetic properties of nanocarbon

    International Nuclear Information System (INIS)

    Lähderanta, E.; Ryzhov, V.A.; Lashkul, A.V.; Galimov, D.M.; Titkov, A.N.; Matveev, V.V.; Mokeev, M.V.; Kurbakov, A.I.; Lisunov, K.G.

    2015-01-01

    Here are presented investigations of powder and glass-like samples containing carbon nanoparticles, not intentionally doped and doped with Ag, Au and Co. The neutron diffraction study reveals an amorphous structure of the samples doped with Au and Co, as well as the magnetic scattering due to a long-range FM order in the Co-doped sample. The composition and molecular structure of the sample doped with Au is clarified with the NMR investigations. The temperature dependence of the magnetization, M (T), exhibits large irreversibility in low fields of B=1–7 mT. M (B) saturates already above 2 T at high temperatures, but deviates from the saturation behavior below ~50 (150 K). Magnetic hysteresis is observed already at 300 K and exhibits a power-law temperature decay of the coercive field, B c (T). The macroscopic behavior above is typical of an assembly of partially blocked magnetic nanoparticles. The values of the saturation magnetization, M s , and the blocking temperature, T b , are obtained as well. However, the hysteresis loop in the Co-doped sample differs from that in other samples, and the values of B c and M s are noticeably increased. - Highlights: • We have investigated powder and glassy samples with carbon nanoparticles. • They include an undoped sample and those doped with Ag, Au and Co. • Neutron diffraction study reveals amorphous structure of Au- and Co-doped samples. • Composition and molecular structure of Au-doped sample was investigated with NMR. • Magnetic behavior is typical of an assembly of partially blocked magnetic nanoparticles

  4. Proton irradiation effects on beryllium – A macroscopic assessment

    Energy Technology Data Exchange (ETDEWEB)

    Simos, Nikolaos, E-mail: simos@bnl.gov [Nuclear Sciences & Technology Department, Brookhaven National Laboratory, Upton, NY, 11973 (United States); Elbakhshwan, Mohamed [Nuclear Sciences & Technology Department, Brookhaven National Laboratory, Upton, NY, 11973 (United States); Zhong, Zhong [Photon Sciences, NSLS II, Brookhaven National Laboratory, Upton, NY, 11973 (United States); Camino, Fernando [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973 (United States)

    2016-10-15

    Beryllium, due to its excellent neutron multiplication and moderation properties, in conjunction with its good thermal properties, is under consideration for use as plasma facing material in fusion reactors and as a very effective neutron reflector in fission reactors. While it is characterized by unique combination of structural, chemical, atomic number, and neutron absorption cross section it suffers, however, from irradiation generated transmutation gases such as helium and tritium which exhibit low solubility leading to supersaturation of the Be matrix and tend to precipitate into bubbles that coalesce and induce swelling and embrittlement thus degrading the metal and limiting its lifetime. Utilization of beryllium as a pion production low-Z target in high power proton accelerators has been sought both for its low Z and good thermal properties in an effort to mitigate thermos-mechanical shock that is expected to be induced under the multi-MW power demand. To assess irradiation-induced changes in the thermal and mechanical properties of Beryllium, a study focusing on proton irradiation damage effects has been undertaken using 200 MeV protons from the Brookhaven National Laboratory Linac and followed by a multi-faceted post-irradiation analysis that included the thermal and volumetric stability of irradiated beryllium, the stress-strain behavior and its ductility loss as a function of proton fluence and the effects of proton irradiation on the microstructure using synchrotron X-ray diffraction. The mimicking of high temperature irradiation of Beryllium via high temperature annealing schemes has been conducted as part of the post-irradiation study. This paper focuses on the thermal stability and mechanical property changes of the proton irradiated beryllium and presents results of the macroscopic property changes of Beryllium deduced from thermal and mechanical tests.

  5. Innovations in macroscopic evaluation of pancreatic specimens and radiologic correlation

    Directory of Open Access Journals (Sweden)

    Charikleia Triantopoulou

    2016-01-01

    Full Text Available The purpose of this study was to evaluate the feasibility of a novel dissection technique of surgical specimens in different cases of pancreatic tumors and provide a radiologic pathologic correlation. In our hospital, that is a referral center for pancreatic diseases, the macroscopic evaluation of the pancreatectomy specimens is performed by the pathologists using the axial slicing technique (instead of the traditional procedure with longitudinal opening of the main pancreatic and/or common bile duct and slicing along the plane defined by both ducts. The specimen is sliced in an axial plane that is perpendicular to the longitudinal axis of the descending duodenum. The procedure results in a large number of thin slices (3–4 mm. This plane is identical to that of CT or MRI and correlation between pathology and imaging is straightforward. We studied 70 cases of suspected different solid and cystic pancreatic tumors and we correlated the tumor size and location, the structure—consistency (areas of necrosis—hemorrhage—fibrosis—inflammation, the degree of vessels’ infiltration, the size of pancreatic and common bile duct and the distance from resection margins. Missed findings by imaging or pitfalls were recorded and we tried to explain all discrepancies between radiology evaluation and the histopathological findings. Radiologic-pathologic correlation is extremely important, adding crucial information on imaging limitations and enabling quality assessment of surgical specimens. The deep knowledge of different pancreatic tumors’ consistency and way of extension helps to improve radiologists’ diagnostic accuracy and minimize the radiological-surgical mismatching, preventing patients from unnecessary surgery.

  6. Nuclear magnetic resonance studies of macroscopic morphology and dynamics

    International Nuclear Information System (INIS)

    Barrall, G.A.; Lawrence Berkeley Lab., CA

    1995-09-01

    Nuclear magnetic resonance techniques are traditionally used to study molecular level structure and dynamics with a noted exception in medically applied NMR imaging (MRI). In this work, new experimental methods and theory are presented relevant to the study of macroscopic morphology and dynamics using NMR field gradient techniques and solid state two-dimensional exchange NMR. The goal in this work is not to take some particular system and study it in great detail, rather it is to show the utility of a number of new and novel techniques using ideal systems primarily as a proof of principle. By taking advantage of the analogy between NMR imaging and diffraction, one may simplify the experiments necessary for characterizing the statistical properties of the sample morphology. For a sample composed of many small features, e.g. a porous medium, the NMR diffraction techniques take advantage of both the narrow spatial range and spatial isotropy of the sample's density autocorrelation function to obtain high resolution structural information in considerably less time than that required by conventional NMR imaging approaches. The time savings of the technique indicates that NMR diffraction is capable of finer spatial resolution than conventional NMR imaging techniques. Radio frequency NMR imaging with a coaxial resonator represents the first use of cylindrically symmetric field gradients in imaging. The apparatus as built has achieved resolution at the micron level for water samples, and has the potential to be very useful in the imaging of circularly symmetric systems. The study of displacement probability densities in flow through a random porous medium has revealed the presence of features related to the interconnectedness of the void volumes. The pulsed gradient techniques used have proven successful at measuring flow properties for time and length scales considerably shorter than those studied by more conventional techniques

  7. NMR studies of macroscopic and microscopic properties of liquid crystals

    International Nuclear Information System (INIS)

    Hughes, J.R.

    1998-03-01

    The work presented is concerned with studies of orientational order in liquid crystals and the behaviour of certain mesophases. The experimental technique used in common with all the work is deuterium NMR spectroscopy. Much of the work involves studies of the orientational order of deuteriated solute molecules dissolved in liquid crystal solvents. Chapter 1 gives an introduction to liquid crystals followed by a quantitative description of orientational order. Deuterium NMR in liquid crystals is described and an outline of the molecular field theory behind the orientational order of a rigid, biaxial solute in a uniaxial mesophase is given. In Chapter 2 a novel type of mesophase induction is studied using NMR, where a solute induces up to two extra phases in a discotic mesogen depending on its concentration. The purpose of this work is to try to gain an understanding into the mechanism of the phase induction involved. Chapter 3 is concerned primarily with the macroscopic behaviour of the nematic phase formed by a semi-rigid main-chain polymer in solution. Of particular interest is the study of the reorientation of the monodomain, once the director has been rotated with respect to the magnetic field of the NMR spectrometer. A mesogen which has been claimed to exhibit a biaxial nematic phase is studied in Chapter 4, in order to determine the symmetry of the phase using NMR. Finally, Chapter 5 deals with the differing behaviour of a liquid crystal monomer and its dimer dissolved in common nematic solvents in order to determine whether this agrees with molecular field theory. (author)

  8. Chronic electroconvulsive stimulation but not chronic restraint stress modulates mRNA expression of voltage-dependent potassium channels Kv7.2 and Kv11.1 in the rat piriform cortex

    DEFF Research Database (Denmark)

    Hjæresen, Marie-Louise; Hageman, Ida; Wörtwein, Gitta

    2008-01-01

    The mechanisms by which stress and electroconvulsive therapy exert opposite effects on the course of major depression are not known. Potential candidates might include the voltage-dependent potassium channels. Potassium channels play an important role in maintaining the resting membrane potential...... and controlling neuronal excitability. To explore this hypothesis, we examined the effects of one or several electroconvulsive stimulations and chronic restraint stress (6 h/day for 21 days) on the expression of voltage-dependent potassium channel Kv7.2, Kv11.1, and Kv11.3 mRNA in the rat brain using in situ...... hybridization. Repeated, but not acute, electroconvulsive stimulation increased Kv7.2 and Kv11.1 mRNA levels in the piriform cortex. In contrast, restraint stress had no significant effect on mRNA expression of Kv7.2, Kv11.1, or Kv11.3 in any of the brain regions examined. Thus, it appears that the investigated...

  9. The acrylamide (S)-2 as a positive and negative modulator of Kv7 channels expressed in Xenopus laevis oocytes

    DEFF Research Database (Denmark)

    Blom, Sigrid Marie; Schmitt, Nicole; Jensen, Henrik Sindal

    2009-01-01

    Kv7.2-5, is now in clinical trial phase III for the treatment of partial onset seizures. One of the main obstacles in developing Kv7 channel active drugs has been to identify compounds that can discriminate between the neuronal subtypes, a feature that could help diminish side effects and increase...

  10. The schizophrenia-associated Kv11.1-3.1 isoform results in reduced current accumulation during repetitive brief depolarizations.

    Directory of Open Access Journals (Sweden)

    Juliane Heide

    Full Text Available Recent genome wide association studies identified a brain and primate specific isoform of a voltage-gated potassium channel, referred to as Kv11.1-3.1, which is significantly associated with schizophrenia. The 3.1 isoform replaces the first 102 amino acids of the most abundant isoform (referred to as Kv11.1-1A with six unique amino acids. Here we show that the Kv11.1-3.1 isoform has faster rates of channel deactivation but a slowing of the rates of inactivation compared to the Kv11.1-1A isoform. The Kv11.1-3.1 isoform also has a significant depolarizing shift in the voltage-dependence of steady-state inactivation. The consequence of the altered gating kinetics is that there is lower current accumulation for Kv11.1-3.1 expressing cells during repetitive action potential firing compared to Kv11.1-1A expressing cells, which in turn will result in longer lasting trains of action potentials. Increased expression of Kv11.1-3.1 channels in the brain of schizophrenia patients might therefore contribute to disorganized neuronal firing.

  11. Physiological role of Kv1.3 channel in T lymphocyte cell investigated quantitatively by kinetic modeling.

    Directory of Open Access Journals (Sweden)

    Panpan Hou

    Full Text Available Kv1.3 channel is a delayed rectifier channel abundant in human T lymphocytes. Chronic inflammatory and autoimmune disorders lead to the over-expression of Kv1.3 in T cells. To quantitatively study the regulatory mechanism and physiological function of Kv1.3 in T cells, it is necessary to have a precise kinetic model of Kv1.3. In this study, we firstly established a kinetic model capable to precisely replicate all the kinetic features for Kv1.3 channels, and then constructed a T-cell model composed of ion channels including Ca2+-release activated calcium (CRAC channel, intermediate K+ (IK channel, TASK channel and Kv1.3 channel for quantitatively simulating the changes in membrane potentials and local Ca2+ signaling messengers during activation of T cells. Based on the experimental data from current-clamp recordings, we successfully demonstrated that Kv1.3 dominated the membrane potential of T cells to manipulate the Ca2+ influx via CRAC channel. Our results revealed that the deficient expression of Kv1.3 channel would cause the less Ca2+ signal, leading to the less efficiency in secretion. This was the first successful attempt to simulate membrane potential in non-excitable cells, which laid a solid basis for quantitatively studying the regulatory mechanism and physiological role of channels in non-excitable cells.

  12. Parameter design and performance simulation of a 10 kV voltage compensation type active superconducting fault current limiter

    International Nuclear Information System (INIS)

    Chen, L.; Tang, Y.J.; Song, M.; Shi, J.; Ren, L.

    2013-01-01

    Highlights: •For a practical 10 kV system, the 10 kV active SFCL’s basic parameters are designed. •Under different fault conditions, the 10 kV active SFCL’s performances are simulated. •The designed 10 kV active SFCL’s engineering feasibility is discussed preliminarily. -- Abstract: Since the introduction of superconducting fault current limiter (SFCL) into electrical distribution system may be a good choice with economy and practicability, the parameter design and current-limiting characteristics of a 10 kV voltage compensation type active SFCL are studied in this paper. Firstly, the SFCL’s circuit structure and operation principle are presented. Then, taking a practical 10 kV distribution system as its application object, the SFCL’s basic parameters are designed to meet the system requirements. Further, using MATLAB, the detailed current-limiting performances of the 10 kV active SFCL are simulated under different fault conditions. The simulation results show that the active SFCL can deal well with the faults, and the parameter design’s suitability can be testified. At the end, in view of the engineering feasibility of the 10 kV active SFCL, some preliminary discussions are carried out

  13. Silencing of Kv4.1 potassium channels inhibits cell proliferation of tumorigenic human mammary epithelial cells

    International Nuclear Information System (INIS)

    Jang, Soo Hwa; Choi, Changsun; Hong, Seong-Geun; Yarishkin, Oleg V.; Bae, Young Min; Kim, Jae Gon; O'Grady, Scott M.; Yoon, Kyong-Ah; Kang, Kyung-Sun; Ryu, Pan Dong; Lee, So Yeong

    2009-01-01

    Potassium channel activity has been shown to facilitate cell proliferation in cancer cells. In the present study, the role of Kv4.1 channels in immortal and tumorigenic human mammary epithelial cells was investigated. Kv4.1 protein expression was positively correlated with tumorigenicity. Moreover, transfection with siRNAs targeting Kv4.1 mRNA suppressed proliferation of tumorigenic mammary epithelial cells. Experiments using mRNA isolated from human breast cancer tissues revealed that the level of Kv4.1 mRNA expression varied depending on the stage of the tumor. Kv4.1 protein expression increased during stages T2 and T3 compared to normal tissue. These results demonstrated that Kv4.1 plays a role in proliferation of tumorigenic human mammary epithelial cells. In addition, elevated Kv4.1 expression may be useful as a diagnostic marker for staging mammary tumors and selective blockers of Kv4.1 may serve to suppress tumor cell proliferation.

  14. Structured pathology reporting improves the macroscopic assessment of rectal tumour resection specimens.

    Science.gov (United States)

    King, Simon; Dimech, Margaret; Johnstone, Susan

    2016-06-01

    We examined whether introduction of a structured macroscopic reporting template for rectal tumour resection specimens improved the completeness and efficiency in collecting key macroscopic data elements. Fifty free text (narrative) macroscopic reports retrieved from 2012 to 2014 were compared with 50 structured macroscopic reports from 2013 to 2015, all of which were generated at John Hunter Hospital, Newcastle, NSW. The six standard macroscopic data elements examined in this study were reported in all 50 anatomical pathology reports using a structured macroscopic reporting dictation template. Free text reports demonstrated significantly impaired data collection when recording intactness of mesorectum (p<0.001), relationship to anterior peritoneal reflection (p=0.028) and distance of tumour to the non-peritonealised circumferential margin (p<0.001). The number of words used was also significantly (p<0.001) reduced using pre-formatted structured reports compared to free text reports. The introduction of a structured reporting dictation template improves data collection and may reduce the subsequent administrative burden when macroscopically evaluating rectal resections. Copyright © 2016 Royal College of Pathologists of Australasia. Published by Elsevier B.V. All rights reserved.

  15. Kv2 Ion Channels Determine the Expression and Localization of the Associated AMIGO-1 Cell Adhesion Molecule in Adult Brain Neurons

    Directory of Open Access Journals (Sweden)

    Hannah I. Bishop

    2018-01-01

    Full Text Available Voltage-gated K+ (Kv channels play important roles in regulating neuronal excitability. Kv channels comprise four principal α subunits, and transmembrane and/or cytoplasmic auxiliary subunits that modify diverse aspects of channel function. AMIGO-1, which mediates homophilic cell adhesion underlying neurite outgrowth and fasciculation during development, has recently been shown to be an auxiliary subunit of adult brain Kv2.1-containing Kv channels. We show that AMIGO-1 is extensively colocalized with both Kv2.1 and its paralog Kv2.2 in brain neurons across diverse mammals, and that in adult brain, there is no apparent population of AMIGO-1 outside of that colocalized with these Kv2 α subunits. AMIGO-1 is coclustered with Kv2 α subunits at specific plasma membrane (PM sites associated with hypolemmal subsurface cisternae at neuronal ER:PM junctions. This distinct PM clustering of AMIGO-1 is not observed in brain neurons of mice lacking Kv2 α subunit expression. Moreover, in heterologous cells, coexpression of either Kv2.1 or Kv2.2 is sufficient to drive clustering of the otherwise uniformly expressed AMIGO-1. Kv2 α subunit coexpression also increases biosynthetic intracellular trafficking and PM expression of AMIGO-1 in heterologous cells, and analyses of Kv2.1 and Kv2.2 knockout mice show selective loss of AMIGO-1 expression and localization in neurons lacking the respective Kv2 α subunit. Together, these data suggest that in mammalian brain neurons, AMIGO-1 is exclusively associated with Kv2 α subunits, and that Kv2 α subunits are obligatory in determining the correct pattern of AMIGO-1 expression, PM trafficking and clustering.

  16. miR-1 is increased in pulmonary hypertension and downregulates Kv1.5 channels in rat pulmonary arteries.

    Science.gov (United States)

    Mondejar-Parreño, Gema; Callejo, María; Barreira, Bianca; Morales-Cano, Daniel; Esquivel-Ruiz, Sergio; Moreno, Laura; Cogolludo, Angel; Perez-Vizcaino, Francisco

    2018-05-02

    ■The expression of miR-1 is increased in lungs from the Hyp/Su5416 PAH rat model. ■PASMC from this animal model are more depolarised and show decreased expression and activity of Kv1.5. ■miR-1 directly targets Kv1.5 channels, reduces Kv1.5 activity and induces membrane depolarization. ■Antagomir-1 prevents Kv1.5 channel downregulation and the depolarization induced by hypoxia/Su5416 exposition. Impairment of voltage-dependent potassium channel (Kv) plays a central role in the development of cardiovascular diseases, including pulmonary arterial hypertension (PAH). MicroRNAs (miRNAs) are non-coding RNAs that regulate gene expression by binding to the 3'-UTR region of specific mRNAs. The aim of this study was to analyze the effects of miR-1 on Kv channel function in pulmonary arteries (PA). Kv channel activity was studied in PA from healthy animals transfected with miR-1 or scrambled-miR. Kv currents were studied using the whole-cell configuration of patch-clamp technique. The characterization of the Kv1.5 currents was performed with the selective inhibitor DPO-1. miR-1 expression was increased and Kv1.5 channels were decreased in lungs from a rat model of PAH induced by hypoxia and Su5416. miR-1 transfection increased cell capacitance, reduced Kv1.5 currents and induced membrane depolarization in isolated pulmonary artery smooth muscle cells (PASMCs). Luciferase reporter assay indicated that KCNA5, which encodes Kv1.5 channels, is a direct target gene of miR-1. Incubation of PA with Su5416 and hypoxia (3% O 2 ) increased miR-1 and induced a decline in Kv1.5 currents, which was prevented by antagomiR-1. In conclusion, these data indicate that miR-1 induces PASMC hypertrophy and reduces the activity and expression of Kv channels, suggesting a pathophysiological role in PAH. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  17. Molecular Expression and Pharmacological Evidence for a Functional Role of Kv7 Channel Subtypes in Guinea Pig Urinary Bladder Smooth Muscle

    Science.gov (United States)

    Afeli, Serge A. Y.; Malysz, John; Petkov, Georgi V.

    2013-01-01

    Voltage-gated Kv7 (KCNQ) channels are emerging as essential regulators of smooth muscle excitability and contractility. However, their physiological role in detrusor smooth muscle (DSM) remains to be elucidated. Here, we explored the molecular expression and function of Kv7 channel subtypes in guinea pig DSM by RT-PCR, qRT-PCR, immunohistochemistry, electrophysiology, and isometric tension recordings. In whole DSM tissue, mRNAs for all Kv7 channel subtypes were detected in a rank order: Kv7.1~Kv7.2Kv7.3~Kv7.5Kv7.4. In contrast, freshly-isolated DSM cells showed mRNA expression of: Kv7.1~Kv7.2Kv7.5Kv7.3~Kv7.4. Immunohistochemical confocal microscopy analyses of DSM, conducted by using co-labeling of Kv7 channel subtype-specific antibodies and α-smooth muscle actin, detected protein expression for all Kv7 channel subtypes, except for the Kv7.4, in DSM cells. L-364373 (R-L3), a Kv7.1 channel activator, and retigabine, a Kv7.2-7.5 channel activator, inhibited spontaneous phasic contractions and the 10-Hz electrical field stimulation (EFS)-induced contractions of DSM isolated strips. Linopiridine and XE991, two pan-Kv7 (effective at Kv7.1-Kv7.5 subtypes) channel inhibitors, had opposite effects increasing DSM spontaneous phasic and 10 Hz EFS-induced contractions. EFS-induced DSM contractions generated by a wide range of stimulation frequencies were decreased by L-364373 (10 µM) or retigabine (10 µM), and increased by XE991 (10 µM). Retigabine (10 µM) induced hyperpolarization and inhibited spontaneous action potentials in freshly-isolated DSM cells. In summary, Kv7 channel subtypes are expressed at mRNA and protein levels in guinea pig DSM cells. Their pharmacological modulation can control DSM contractility and excitability; therefore, Kv7 channel subtypes provide potential novel therapeutic targets for urinary bladder dysfunction. PMID:24073284

  18. A charge-pump 60kV modulator for the ISOLDE target extraction voltage

    CERN Document Server

    Barlow, R A; Fowler, A; Gaudillet, H; Gharsa, T; Schipper, J

    2015-01-01

    The ISOLDE facility at CERN provides radioactive ion beams to a number of experimental stations. These ions are produced by a metal target, floating at 60 kV, which is impacted by a 1.4 GeV high intensity proton beam. The ions are then accelerated by a grounded extraction electrode to 60 keV, before transport to the experimental area. During proton beam impact extremely high ionisation of the volume around the target gives rise to significant leakage current which results in loss of charge on the effective target capacitance of approximately 6 nF. If short life-time isotopes are to be studied, the 60 kV must be re-established within a maximum of 10 ms. Recharging the target capacitance to 60 kV and to the required stability of better than 10-4 precludes a direct charging system and an alternative method of re-establishing the 60 kV is used. The present system [1], in operation since 1991, employs a resonant circuit which is triggered 35 µs prior to beam impact. This circuit transfers the charge on the effec...

  19. Workers exposure to electric fields in 400 kV substations and overhead line works

    International Nuclear Information System (INIS)

    Elovaara, J.; Kuisti, H.; Korpinen, L.

    2010-01-01

    The maximum exposing electric field strength magnitude in the highly inhomogeneous 400 kV electric field under work conditions can reach the value of several tens of kV/m. In spite of this the average current density is, in Finland, always lower than 10 mA/m 2 . Furthermore, the total body currents or contact currents are in 400 kV works clearly less than the limit value proposed by the EU's draft for Directive. On the basis of the obtained results it can be concluded that from the limit value point of view it is not necessary to take further actions to reduce the exposure of the workers when they are working in 400 kV substations and on 400 kV overhead lines. However, because the transient peak values of the contact current can be painful and disturb work, it is advisable to develop a safe and reliable method to connect the worker and the work object in the common ground (equipotential bonding). (authors)

  20. Modellering og måling af metan-emission fra kvæg

    DEFF Research Database (Denmark)

    Storm, I; Hellwing, Anne Louise Frydendahl; Nielsen, N I

    2011-01-01

    Udvikling af og kendskab til de metoder, der bruges til måling af kvægs metan-emission udgør en vigtig del af forskningen indenfor området. I dette indlæg præsenteres de mest anvendte metoder til måling og estimation af kvægs metan-emission, herunder modeller, in vitro inkubation, kammer-metoder,......-metoder, SF6-metoden og CO2-metoden. De enkelte metoder beskrives og fordele, ulemper og anvendelsesområder sammenlignes. Dette er vigtig baggrundsinformation for forståelse og fortolkning af øvrige forskningsresultater og for at kunne planlægge fremtidige projekter.......Udvikling af og kendskab til de metoder, der bruges til måling af kvægs metan-emission udgør en vigtig del af forskningen indenfor området. I dette indlæg præsenteres de mest anvendte metoder til måling og estimation af kvægs metan-emission, herunder modeller, in vitro inkubation, kammer...

  1. A capacitive level shifter for high voltage (2.5kV)

    DEFF Research Database (Denmark)

    Andersen, Thomas; Andersen, Michael A. E.; Thomsen, Ole Cornelius

    2012-01-01

    with focus on low power consumption as well as low capacitive load between the floating half-bridge node and ground (output capacitance). The operation of the level-shifter is tested and verified by measurements on a prototype half-bridge gate driver. Results conclude stabile operation at 2.44kV, 50k...

  2. Differential expression of KvLQT1 and its regulator IsK in mouse epithelia

    NARCIS (Netherlands)

    Demolombe, S.; Franco, D.; de Boer, P.; Kuperschmidt, S.; Roden, D.; Pereon, Y.; Jarry, A.; Moorman, A. F.; Escande, D.

    2001-01-01

    KCNQ1 is the human gene responsible in most cases for the long QT syndrome, a genetic disorder characterized by anomalies in cardiac repolarization leading to arrhythmias and sudden death. KCNQ1 encodes a pore-forming K+ channel subunit termed KvLQT1 which, in association with its regulatory

  3. Effects of electromagnetic field of 33 and 275 kV influences on ...

    African Journals Online (AJOL)

    The effects of electromagnetic fields (EMF) from 33 and 275 kV high voltage transmission line on biochemical and antioxidant system changes in mustard leaf (Brassica chinensis) were investigated under field condition. Mustard leaves were exposed to EMF from power lines at distances of 0, 3, 6, 9, 10, 12, 15, 18, 20, 21, ...

  4. A neutral grounding metallic resistor failure in a 35 kV network

    Directory of Open Access Journals (Sweden)

    Simić Ninoslav

    2011-01-01

    Full Text Available This paper presents the results of observations and measurements of the impedance of the metal resistor for grounding neutral of the 35 kV network, before and after damaging event. The proposed measures are to be taken in order to eliminate a failure in this particular case, as well as the prevention of similar events.

  5. Interlaboratory comparison of measuring results of magnetic field near 400 kV overhead power line

    Directory of Open Access Journals (Sweden)

    Grbić Maja

    2012-01-01

    Full Text Available The paper presents a comparison of measured results of magnetic field near 400 kV overhead power lines obtained by three laboratories. This interlaboratory comparison was performed to ensure confidence in the quality of the test results. The measured results were analyzed with standard methods, using En number, based on which the evaluation of the laboratories was performed.

  6. Design and performance of a 30 KV electron gun with ten independent cathodes & a magnetic lens.

    Energy Technology Data Exchange (ETDEWEB)

    Rudys, Joseph Matthew; Reed, Kim Warren

    2006-08-01

    Measurements on a 30 kV electron gun with ten independent cathodes, operating in a 6.5 Tesla (T) magnetic field are presented. An earlier paper covered the design of this electron gun [1]. Experimental results are compared to model predictions. Beam current is compared to theoretical space charge limited flow.

  7. Udbredelse af den baktielle zoonose i danske kvægbesætninger

    DEFF Research Database (Denmark)

    Bødker, Rene; Christoffersen, Anna-Bodil

    2008-01-01

    Tankmælksprøver fra 742 mælkeleverende kvægejendomme blev analyseret for antistoffer mod Coxiella burnetii i en ELISA. 57% af ejendommene havde positive prøver i den serologiske test. Prøverne var diagnostiske indsendelser til DTU Veterinærinstituttet og udgjorde derfor ikke en repræsentativ...

  8. Independent and cooperative motions of the Kv1.2 channel: voltage sensing and gating.

    Science.gov (United States)

    Yeheskel, Adva; Haliloglu, Turkan; Ben-Tal, Nir

    2010-05-19

    Voltage-gated potassium (Kv) channels, such as Kv1.2, are involved in the generation and propagation of action potentials. The Kv channel is a homotetramer, and each monomer is composed of a voltage-sensing domain (VSD) and a pore domain (PD). We analyzed the fluctuations of a model structure of Kv1.2 using elastic network models. The analysis suggested a network of coupled fluctuations of eight rigid structural units and seven hinges that may control the transition between the active and inactive states of the channel. For the most part, the network is composed of amino acids that are known to affect channel activity. The results suggested allosteric interactions and cooperativity between the subunits in the coupling between the motion of the VSD and the selectivity filter of the PD, in accordance with recent empirical data. There are no direct contacts between the VSDs of the four subunits, and the contacts between these and the PDs are loose, suggesting that the VSDs are capable of functioning independently. Indeed, they manifest many inherent fluctuations that are decoupled from the rest of the structure. In general, the analysis suggests that the two domains contribute to the channel function both individually and cooperatively. Copyright 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  9. Measurements of Voltage Harmonics in 400 kV Transmission Network

    Directory of Open Access Journals (Sweden)

    Ryszard Pawełek

    2014-06-01

    Full Text Available The paper deals with the analysis of voltage harmonics measurements performed in the 400 kV transmission network. The voltage was measured by means of three transducers: resistive voltage divider, inductive measuring transformer and capacitive voltage measuring transformer. Instrument errors were estimated for measuring transformers with reference to the harmonic values obtained from the voltage divider.

  10. Modification of 300kV RF Ion Source for 1-MV Electrostatic Accelerator at KOMAC

    International Nuclear Information System (INIS)

    Kim, Dae-Il; Kwon, Hyeok-Jung; Park, Sae-Hoon; Cho, Yong-Sub

    2015-01-01

    The specifications of the 1-MV electrostatic accelerator are shown as below. High voltage power supply is electron transformer rectifier (ELV) type which was developed in Nuclear Physics Institute (Novosibirsk) for industrial electron accelerators. And accelerator column consists of alumina and metal electrode rings were 0.5m-long brazed structure which can be installed horizontally. In case of ion source for 1-MV electrostatic accelerator, it is chosen a thonemann type rf ion source and 300-kV test-stand was made up to confirm the stable operating conditions. High voltage power supply is fabricated by domestic company, and its operation has been confirming at KOMAC site. Equally, the ion source of 300-kV test-stand should be modified to install into the high voltage power supply. In this paper, modification of ion source of 300-kV test-stand for 1-MV electrostatic accelerator is presented and its processes are considered. 300-kV RF ion source and power supply are testing for the 1-MV electrostatic accelerator and trying for combination between them. The 1-MV electrostatic accelerator will be fabricated with domestic companies and tested in the beam application research building at KOMAC

  11. Modification of 300kV RF Ion Source for 1-MV Electrostatic Accelerator at KOMAC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae-Il; Kwon, Hyeok-Jung; Park, Sae-Hoon; Cho, Yong-Sub [KOMAC, Gyeongju (Korea, Republic of)

    2015-05-15

    The specifications of the 1-MV electrostatic accelerator are shown as below. High voltage power supply is electron transformer rectifier (ELV) type which was developed in Nuclear Physics Institute (Novosibirsk) for industrial electron accelerators. And accelerator column consists of alumina and metal electrode rings were 0.5m-long brazed structure which can be installed horizontally. In case of ion source for 1-MV electrostatic accelerator, it is chosen a thonemann type rf ion source and 300-kV test-stand was made up to confirm the stable operating conditions. High voltage power supply is fabricated by domestic company, and its operation has been confirming at KOMAC site. Equally, the ion source of 300-kV test-stand should be modified to install into the high voltage power supply. In this paper, modification of ion source of 300-kV test-stand for 1-MV electrostatic accelerator is presented and its processes are considered. 300-kV RF ion source and power supply are testing for the 1-MV electrostatic accelerator and trying for combination between them. The 1-MV electrostatic accelerator will be fabricated with domestic companies and tested in the beam application research building at KOMAC.

  12. Beam Extraction for 1-MV Electrostatic Accelerator at the 300 kV Test Stand

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sae-Hoon; Kim, Yu-Seok [Dongguk University, Seoul (Korea, Republic of); Kwon, Hyeok-Jung; Cho, Yong-Sub [KOMAC, Gyeongju (Korea, Republic of)

    2015-05-15

    The Korea Multipurpose Accelerator Complex (KOMAC) has been developing a 300-kV test stand for a 1-MV electrostatic accelerator ion source. The ion source in the high-pressure vessel is required to have a high reliability. The test stand has been proposed and developed to confirm the stable operating conditions of the ion source. The ion source will be tested at the test stand to verify the long-time operating conditions. The test stand comprises a 300-kV high-voltage terminal, a battery for the ion-source power, a 60-Hz inverter, 200-MHz RF power, a 5-kV extraction power supply, a 300-kV accelerating tube, and a vacuum system. A beam extraction experiment for the test stand was performed, and the beam current was measured using a faraday cup in the chamber. A beam extraction results for the RF ion source will be presented. Beam extraction from the RF ion source of the test stand is verified by measuring the beam current with a faraday cup in the chamber. Thus far NI Labview, PLC and faraday cup have been used to measure the beam current. The OPC server is useful for monitoring the PLC values. The average beam current of (a), (b) and (c) shown in figure 2 are 110.241µA, 105.8597µA and 103.5278µA respectively.

  13. The 150 kV cp microfocus X-ray unit

    NARCIS (Netherlands)

    Fontijn, L.A.

    1979-01-01

    Development of microfocus X-ray technique is defined. Advantages on other methods, principle of operation and the material comprising an intense electron source imaged on an X-ray target by means of a double magnetic lense system, are described. Resolution value at 150 kV is the imaging of a 0.1 mm

  14. A fast 30 kV 5 kHz repetition rate resonant capacitor charger

    NARCIS (Netherlands)

    Beckers, F.J.C.M.; Huiskamp, T.; van Heesch, E.J.M.; Pemen, A.J.M.

    2016-01-01

    A novel circuit topology of a fast 30 kV resonant capacitor charger is presented in this paper. The charger is designed for high repetition rate spark gap based pulsed power modulators. A spark gap can fire spontaneously (pre-firing) during charging of a capacitor bank due to poor dielectric

  15. Characterisation of 10 kV 10 A SiC MOSFET

    DEFF Research Database (Denmark)

    Eni, Emanuel-Petre; Incau, Bogdan Ioan; Munk-Nielsen, Stig

    2015-01-01

    The objective of this paper is to characterize and evaluate the static and dynamic performances of 10 kV 10 A 4H-SIC MOSFETs at high temperatures. The results show good electrical performances of the SiC MOSFETs for high temperature operations. The double-pulse test results showed interesting...

  16. 10kV SiC MOSFET split output power module

    DEFF Research Database (Denmark)

    Beczkowski, Szymon; Li, Helong; Uhrenfeldt, Christian

    2015-01-01

    The poor body diode performance of the first generation of 10kV SiC MOSFETs and the parasitic turn-on phenomenon limit the performance of SiC based converters. Both these problems can potentially be mitigated using a split output topology. In this paper we present a comparison between a classical...

  17. harmonic load modeling: a case study of 33 kv abuja steel mill feeder

    African Journals Online (AJOL)

    HOD

    An in-depth study of the harmonic orders inherent in a power system network is required ... This paper studied the harmonic orders of the 33 kV Abuja Steel Feeder .... models for various industrial and household electrical ..... Malaysia, 2013.

  18. Reliability assessment of Port Harcourt 33/11kv Distribution System ...

    African Journals Online (AJOL)

    This makes reliability studies an important task besides all the other analyses required for assessing the system performance. The paper presents an analytical approach in the reliability assessment of the Port Harcourt 33/11kV power distribution system. The assessment was performed with the 2009 power outage data ...

  19. K významnému jubileu Květy Sgallové

    Czech Academy of Sciences Publication Activity Database

    Ibrahim, Robert

    2009-01-01

    Roč. 57, č. 4 (2009), s. 608-616 ISSN 0009-0468 Institutional research plan: CEZ:AV0Z90560517 Keywords : Sgallová, Květa * Czech literature * 19th century Subject RIV: AJ - Letters, Mass-media, Audiovision

  20. Full Scale Experimental Study on the Air Insulation of 765kV Transmission Lines

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Boo; Shin, Jeong Woon; Cho, Sung Bae; Chang, Sung Chil; Kwak, Joo Shik [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Kim, Ik Soo; Lee, Heyoung Ho; Kang, Young Sik; Lee, Hong Sik; Choi, Beyoung Joo; Kim, Young Bae [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

    1997-12-31

    Design and construction of testing yard. Technical specification of impulse voltage generator which was installed in testing yard. Corrosion and statistical analysis of test data. Test object setup and test results of flashover characteristic in various paths. Recommended optimum air clearance of 765kV transmission lines. (author). 163 refs., figs.

  1. Pivoting between calmodulin lobes triggered by calcium in the Kv7.2/calmodulin complex.

    Science.gov (United States)

    Alaimo, Alessandro; Alberdi, Araitz; Gomis-Perez, Carolina; Fernández-Orth, Juncal; Bernardo-Seisdedos, Ganeko; Malo, Covadonga; Millet, Oscar; Areso, Pilar; Villarroel, Alvaro

    2014-01-01

    Kv7.2 (KCNQ2) is the principal molecular component of the slow voltage gated M-channel, which strongly influences neuronal excitability. Calmodulin (CaM) binds to two intracellular C-terminal segments of Kv7.2 channels, helices A and B, and it is required for exit from the endoplasmic reticulum. However, the molecular mechanisms by which CaM controls channel trafficking are currently unknown. Here we used two complementary approaches to explore the molecular events underlying the association between CaM and Kv7.2 and their regulation by Ca(2+). First, we performed a fluorometric assay using dansylated calmodulin (D-CaM) to characterize the interaction of its individual lobes to the Kv7.2 CaM binding site (Q2AB). Second, we explored the association of Q2AB with CaM by NMR spectroscopy, using (15)N-labeled CaM as a reporter. The combined data highlight the interdependency of the N- and C-lobes of CaM in the interaction with Q2AB, suggesting that when CaM binds Ca(2+) the binding interface pivots between the N-lobe whose interactions are dominated by helix B and the C-lobe where the predominant interaction is with helix A. In addition, Ca(2+) makes CaM binding to Q2AB more difficult and, reciprocally, the channel weakens the association of CaM with Ca(2+).

  2. Pivoting between calmodulin lobes triggered by calcium in the Kv7.2/calmodulin complex.

    Directory of Open Access Journals (Sweden)

    Alessandro Alaimo

    Full Text Available Kv7.2 (KCNQ2 is the principal molecular component of the slow voltage gated M-channel, which strongly influences neuronal excitability. Calmodulin (CaM binds to two intracellular C-terminal segments of Kv7.2 channels, helices A and B, and it is required for exit from the endoplasmic reticulum. However, the molecular mechanisms by which CaM controls channel trafficking are currently unknown. Here we used two complementary approaches to explore the molecular events underlying the association between CaM and Kv7.2 and their regulation by Ca(2+. First, we performed a fluorometric assay using dansylated calmodulin (D-CaM to characterize the interaction of its individual lobes to the Kv7.2 CaM binding site (Q2AB. Second, we explored the association of Q2AB with CaM by NMR spectroscopy, using (15N-labeled CaM as a reporter. The combined data highlight the interdependency of the N- and C-lobes of CaM in the interaction with Q2AB, suggesting that when CaM binds Ca(2+ the binding interface pivots between the N-lobe whose interactions are dominated by helix B and the C-lobe where the predominant interaction is with helix A. In addition, Ca(2+ makes CaM binding to Q2AB more difficult and, reciprocally, the channel weakens the association of CaM with Ca(2+.

  3. Electronics system for the 150 kV negative ion test stand at BNL

    International Nuclear Information System (INIS)

    Larson, R.A.

    1977-01-01

    The 150 kV test stand at BNL is being used to investigate the extraction, acceleration and transport problems associated with the development of intense negative ion beams. The power supplies associated with these functions as well as the control and monitoring electronics are described

  4. Structural basis for KV7.1/KCNEx interactions in the IKs channel complex

    DEFF Research Database (Denmark)

    Lundby, Alicia; Tseng, Gea-Ny; Schmitt, Nicole

    2010-01-01

    The cardiac I(Ks) current is involved in action potential repolarization, where its primary function is to limit action potential prolongation during sympathetic stimulation. The I(Ks) channel is mainly composed of K(V)7.1 ion channels associated with KCNE1 auxiliary subunits. The availability of...

  5. Axon initial segment Kv1 channels control axonal action potential waveform and synaptic efficacy

    NARCIS (Netherlands)

    Kole, Maarten H. P.; Letzkus, Johannes J.; Stuart, Greg J.

    2007-01-01

    Action potentials are binary signals that transmit information via their rate and temporal pattern. In this context, the axon is thought of as a transmission line, devoid of a role in neuronal computation. Here, we show a highly localized role of axonal Kv1 potassium channels in shaping the action

  6. Innovations in macroscopic evaluation of pancreatic specimens and radiologic correlation

    International Nuclear Information System (INIS)

    Triantopoulou, Charikleia; Papaparaskeva, Kleo; Agalianos, Christos; Dervenis, Christos

    2016-01-01

    •The axial slicing technique offers many advantages in accurate estimation of tumors extend and staging.•Cross-sectional axial imaging is the best technique for accurate radiologic-pathologic correlation.•Correlation may explain any discrepancies between radiological and histopathological findings.•Pathology correlation may offer a better understanding of the missed findings by imaging or pitfalls The axial slicing technique offers many advantages in accurate estimation of tumors extend and staging. Cross-sectional axial imaging is the best technique for accurate radiologic-pathologic correlation. Correlation may explain any discrepancies between radiological and histopathological findings. Pathology correlation may offer a better understanding of the missed findings by imaging or pitfalls The purpose of this study was to evaluate the feasibility of a novel dissection technique of surgical specimens in different cases of pancreatic tumors and provide a radiologic pathologic correlation. In our hospital, that is a referral center for pancreatic diseases, the macroscopic evaluation of the pancreatectomy specimens is performed by the pathologists using the axial slicing technique (instead of the traditional procedure with longitudinal opening of the main pancreatic and/or common bile duct and slicing along the plane defined by both ducts). The specimen is sliced in an axial plane that is perpendicular to the longitudinal axis of the descending duodenum. The procedure results in a large number of thin slices (3–4 mm). This plane is identical to that of CT or MRI and correlation between pathology and imaging is straightforward. We studied 70 cases of suspected different solid and cystic pancreatic tumors and we correlated the tumor size and location, the structure—consistency (areas of necrosis—hemorrhage—fibrosis—inflammation), the degree of vessels’ infiltration, the size of pancreatic and common bile duct and the distance from resection margins

  7. On quantum effects in the dynamics of macroscopic test masses

    International Nuclear Information System (INIS)

    Mueller-Ebhardt, Helge

    2009-01-01

    This thesis provides theoretically a link between the increase of the sensitivity of gravitational-wave detectors and the possibility of preparing macroscopic quantum states in such detectors. In the first part of this thesis, we theoretically explore the quantum measurement noise of an optical speed meter topology, the Sagnac interferometer, equipped with an additional detuned cavity at the output port. This detuned signal-recycling technique was already investigated when applying it to a Michelson interferometer and is used in the gravitational-wave detector GEO600. Together with the quantum noise analysis of the simple Sagnac interferometer, it is the basis of our study: we optimize the Sagnac interferometer's sensitivity towards the detection of a certain gravitational-wave source in the vicinity of a realistic classical noise environment. Motivated by the fact that the Michelson interferometer, as a position meter, with detuned signal-recycling can transduce the gravitational-wave strain into real mirror motion, we compare the transducer effect in a speed and in a position meter. Furthermore, we theoretically investigate the conditional output squeezing of a cavity which is detuned with respect to its carrier and its subcarrier. Therewith we pursue the theoretical analysis of the ponderomotive squeezer. With the knowledge gained in the first part about the quantum measurement process in laser interferometers, the second part of this thesis comprises a theoretical analysis of the conditonal state in positon and momentum of the interferometer's test masses. We motivate not to obtain the conditional states from a stochastic master equation but with the help of the so-called Wiener filtering method. Using this method, we calculate the most general expression for the conditional covariance matrix of the Gaussian state of a test mass under any linear Markovian measurement process. Then we specify to the interferometry and theoretically show under which circumstances

  8. Polymorphic phase transitions: Macroscopic theory and molecular simulation.

    Science.gov (United States)

    Anwar, Jamshed; Zahn, Dirk

    2017-08-01

    Transformations in the solid state are of considerable interest, both for fundamental reasons and because they underpin important technological applications. The interest spans a wide spectrum of disciplines and application domains. For pharmaceuticals, a common issue is unexpected polymorphic transformation of the drug or excipient during processing or on storage, which can result in product failure. A more ambitious goal is that of exploiting the advantages of metastable polymorphs (e.g. higher solubility and dissolution rate) while ensuring their stability with respect to solid state transformation. To address these issues and to advance technology, there is an urgent need for significant insights that can only come from a detailed molecular level understanding of the involved processes. Whilst experimental approaches at best yield time- and space-averaged structural information, molecular simulation offers unprecedented, time-resolved molecular-level resolution of the processes taking place. This review aims to provide a comprehensive and critical account of state-of-the-art methods for modelling polymorph stability and transitions between solid phases. This is flanked by revisiting the associated macroscopic theoretical framework for phase transitions, including their classification, proposed molecular mechanisms, and kinetics. The simulation methods are presented in tutorial form, focusing on their application to phase transition phenomena. We describe molecular simulation studies for crystal structure prediction and polymorph screening, phase coexistence and phase diagrams, simulations of crystal-crystal transitions of various types (displacive/martensitic, reconstructive and diffusive), effects of defects, and phase stability and transitions at the nanoscale. Our selection of literature is intended to illustrate significant insights, concepts and understanding, as well as the current scope of using molecular simulations for understanding polymorphic

  9. Observation of squeezed light and quantum description of the macroscopical body movement

    International Nuclear Information System (INIS)

    Bykov, V.P.

    1992-01-01

    The possibility of a nondemolition measurement (observation) of macroscopical objects in widely distributed quantum mechanical states arises from the fact of the squezzed light observation. Macroscopical bodies -bodies of classical mechanics - are usually in states with narrow wave packets. It is shown that the absence of macroscopical bodies in widely distributed states is due to the focusing influence of the body's gravity field on its wave packet. An evidence that the gravity is essential in the classic limit of quantum mechanics is given. (author). 14 refs, 7 figs

  10. Pharmacological Targeting Of Neuronal Kv7.2/3 Channels: A Focus On Chemotypes And Receptor Sites.

    Science.gov (United States)

    Miceli, Francesco; Soldovieri, Maria Virginia; Ambrosino, Paolo; Manocchio, Laura; Medoro, Alessandro; Mosca, Ilaria; Taglialatela, Maurizio

    2017-10-12

    The Kv7 (KCNQ) subfamily of voltage-gated potassium channels consists of 5 members (Kv7.1-5) each showing a characteristic tissue distribution and physiological roles. Given their functional heterogeneity, Kv7 channels represent important pharmacological targets for development of new drugs for neuronal, cardiac and metabolic diseases. In the present manuscript, we focus on describing the pharmacological relevance and the potential therapeutic applications of drugs acting on neuronally-expressed Kv7.2/3 channels, placing particular emphasis on the different modulator chemotypes, and highlighting their pharmacodynamic and, whenever possible, pharmacokinetic peculiarities. The present work is based on an in-depth search of the currently available scientific literature, and on our own experience and knowledge in the field of neuronal Kv7 channel pharmacology. Space limitations impeded to describe the full pharmacological potential of Kv7 channels; thus, we have chosen to focus on neuronal channels composed of Kv7.2 and Kv7.3 subunits, and to mainly concentrate on their involvement in epilepsy. An astonishing heterogeneity in the molecular scaffolds exploitable to develop Kv7.2/3 modulators is evident, with important structural/functional peculiarities of distinct compound classes. In the present work we have attempted to show the current status and growing potential of the Kv7 pharmacology field. We anticipate a bright future for the field, and we express our hopes that the efforts herein reviewed will result in an improved treatment of hyperexcitability (or any other) diseases. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  11. Radiation dose reduction sinogram affirmed iterative reconstruction and automatic tube voltage modulation(CARE kV) in abdominal CT

    International Nuclear Information System (INIS)

    Shin, Hyun Joo; Chung, Yong Eun; Lee, Young Han; Choi, Jin Young; Park, Mi Suk; Kim, Myeong Jin; Kim, Ki Whang

    2013-01-01

    To evaluate the feasibility of sinogram-affirmed iterative reconstruction (SAFIRE) and automated kV modulation (CARE kV) in reducing radiation dose without increasing image noise for abdominal CT examination. This retrospective study included 77 patients who received CT imaging with an application of CARE kV with or without SAFIRE and who had comparable previous CT images obtained without CARE kV or SAFIRE, using the standard dose (i.e., reference mAs of 240) on an identical CT scanner and reconstructed with filtered back projection (FBP) within 1 year. Patients were divided into two groups: group A (33 patients, CT scanned with CARE kV); and group B (44 patients, scanned after reducing the reference mAs from 240 to 170 and applying both CARE kV and SAFIRE). CT number, image noise for four organs and radiation dose were compared among the two groups. Image noise increased after CARE kV application (p < 0.001) and significantly decreased as SAFIRE strength increased (p < 0.001). Image noise with reduced-mAs scan (170 mAs) in group B became similar to that of standard-dose FBP images after applying CARE kV and SAFIRE strengths of 3 or 4 when measured in the aorta, liver or muscle (p ≥ 0.108). Effective doses decreased by 19.4% and 41.3% for groups A and B, respectively (all, p < 0.001) after application of CARE kV with or without SAFIRE. Combining CARE kV, reduction of mAs from 240 to 170 mAs and noise reduction by applying SAFIRE strength 3 or 4 reduced the radiation dose by 41.3% without increasing image noise compared with the standard-dose FBP images.

  12. Combined kV and MV imaging for real-time tracking of implanted fiducial markers

    International Nuclear Information System (INIS)

    Wiersma, R. D.; Mao Weihua; Xing, L.

    2008-01-01

    In the presence of intrafraction organ motion, target localization uncertainty can greatly hamper the advantage of highly conformal dose techniques such as intensity modulated radiation therapy (IMRT). To minimize the adverse dosimetric effect caused by tumor motion, a real-time knowledge of the tumor position is required throughout the beam delivery process. The recent integration of onboard kV diagnostic imaging together with MV electronic portal imaging devices on linear accelerators can allow for real-time three-dimensional (3D) tumor position monitoring during a treatment delivery. The aim of this study is to demonstrate a near real-time 3D internal fiducial tracking system based on the combined use of kV and MV imaging. A commercially available radiotherapy system equipped with both kV and MV imaging systems was used in this work. A hardware video frame grabber was used to capture both kV and MV video streams simultaneously through independent video channels at 30 frames per second. The fiducial locations were extracted from the kV and MV images using a software tool. The geometric tracking capabilities of the system were evaluated using a pelvic phantom with embedded fiducials placed on a moveable stage. The maximum tracking speed of the kV/MV system is approximately 9 Hz, which is primarily limited by the frame rate of the MV imager. The geometric accuracy of the system is found to be on the order of less than 1 mm in all three spatial dimensions. The technique requires minimal hardware modification and is potentially useful for image-guided radiation therapy systems

  13. Constitutional and somatic methylation status of DMRH19 and KvDMR in Wilms tumor patients

    Directory of Open Access Journals (Sweden)

    Leila C.A. Cardoso

    2012-01-01

    Full Text Available The most frequent epigenetic alterations in Wilms tumor (WT occur at WT2, assigned to 11p15. WT2 consists of two domains: telomeric domain 1 (DMRH19 that contains the IGF2 gene and an imprinted maternally expressed transcript (H19 and centromeric domain 2 (KvDMR that contains the genes KCNQ1, KCNQ1OT1 and CDKN1C. In this work, we used pyrosequencing and MS-MLPA to compare the methylation patterns of DMRH19/KvDMR in blood and tumor samples from 40 WT patients. Normal constitutional KvDMR methylation indicated that most of the epigenetic alterations in WT occur at DMRH19. Constitutional DMRH19 hypermethylation (HM DMRH19 was observed in two patients with Beckwith-Wiedemann syndrome. Pyrosequencing and MS-MLPA showed HM DMRH19 in 28/34 tumor samples: 16/34 with isolated HM DMRH19 and 12/34 with concomitant HM DMRH19 and KvDMR hypomethylation, indicating paternal uniparental disomy. With the exception of one blood sample, the MS-MLPA and pyrosequencing findings were concordant. Diffuse or focal anaplasia was present in five tumor samples and was associated with isolated somatic HM DMRH19 in four of them. Constitutional 11p15 methylation abnormalities were present in 5% of the samples and somatic abnormalities in the majority of tumors. Combined analysis of DMRH19/KvDMR by pyrosequencing and MS-MLPA is beneficial for characterizing epigenetic anomalies in WT, and MS-MLPA is useful and reliable for estimation of DNA methylation in a clinical setting.

  14. Improvement of the 400 kV linac electron source of AmPS

    International Nuclear Information System (INIS)

    Kroes, F.B.; Beuzekom, M.G. van; Dobbe, N.J.; Es, J.T. van; Jansweijer, P.P.M.; Kruijer, A.H.; Luigjes, G.; Sluijk, T.G.B.

    1992-01-01

    The installation of the 900 MeV Amsterdam Pulse Stretcher is nearly completed and its commissioning will start Spring 1992. The existing linac MEA will inject electrons in the AmPS ring. The linacs peak current will be increased from 20 to 80 mA. This requires modification of the 400 kV low emittance gun which now will deliver a peak current of maximum 400 mA instead of 100 mA at a pulse width of 2.1 μsec. The fourfold increase of the peakcurrent is obtained by doubling both the gun perveance (new gun part) and the pulsed extractor voltage. After chopping and pre-bunching more than 80 mA will be available for acceleration in MEA. To obtain optimum beam quality over this increased current range the hot deck electronics, operating at -400 kV, has been exchanged by a state of the art fast high voltage FET switching supply. The increased space charge forces in the beam require stronger electro-static focusing in the first electrostatic gap to define the beam diameter at the gun exit. This is accomplished with a 25 kV controlled power supply. A build in microprocessor, coupled to the local computer by optical fibers, is used to monitor and control the gun parameters. The 5kV gun extractor voltage pulse shape can be monitored by means of an analog fibre transducer with build in calibration. Finally, in order to improve the energy stability of the accelerated electrons a serial electron-tube stabilizer was added to the 400 kV DC power supply. A supply stability of 2. 10 -5 has been achieved. (author). 4 refs.; 6 figs

  15. Touch and step potential analysis at 23.9kV to 4.16kV & 13.8kV to 4.16kV distribution substations with pad-mounted transformers, floating grounds, and other exposed ungrounded metal bodies using WinIGS

    Science.gov (United States)

    Guzman, David G.

    An electrical substation is composed of various subsystems that allow for the effective and safe operation of the power grid. One of the subsystems integrating a conventional substation is defined as the ground grid system. This system allows for the effective operation of the power grid and all the electrical equipment connected to it by providing a ground potential reference, commonly known as the system ground. In addition, the ground grid system provides safety to the workers and the public transiting inside or living nearby a substation by reducing the step and touch potential (or voltage) levels present during a system fault. In today's utility industry practices there is an increasing trend for using pad-mounted electrical equipment for substation applications in an effort to construct new or upgrade existing electrical facilities inside limited property spaces. This thesis work presents an analysis for the effects of touch and step voltages at existing distribution substations where 23.9kV to 4.16kV & 13.8kV to 4.16kV pad-mounted transformers and other pad-mounted switchgear was installed to replace the traditional station class equipment. Moreover, this study will expose modeling techniques employed to define and determine the effects of floating grounds and other exposed metal bodies inside or surrounding these substations using WinIGS; this is in an effort to determine any risks of electric shock associated with this type of installations. The results presented in this work are intended to verify the requirements for the ground grid analysis and design for 4.16kV distribution substations with pad-mounted equipment in order to prevent dangerous step and touch voltage levels appearing at these sites during system faults; and ultimately prevent exposing individuals to the risk of an electric shock.

  16. Kv4 channels underlie the subthreshold-operating A-type K+-current in nociceptive dorsal root ganglion neurons

    Directory of Open Access Journals (Sweden)

    Thanawath R Na Phuket

    2009-07-01

    Full Text Available The dorsal root ganglion (DRG contains heterogeneous populations of sensory neurons including primary nociceptive neurons and C-fibers implicated in pain signaling.  Recent studies have demonstrated DRG hyperexcitability associated with downregulation of A-type K+ channels; however, the molecular correlate of the corresponding A-type K+ current (IA has remained hypothetical.  Kv4 channels may underlie the IA in DRG neurons.  We combined electrophysiology, molecular biology (whole-tissue and single-cell RT-PCR and immunohistochemistry to investigate the molecular basis of the IA in acutely dissociated DRG neurons from 7-8 day-old rats.  Whole-cell recordings demonstrate a robust tetraethylammonium-resistant (20 mM and 4-aminopyridine-sensitive (5 mM IA.  Matching Kv4 channel properties, activation and inactivation of this IA occur in the subthreshold range of membrane potentials and the rate of recovery from inactivation is rapid and voltage-dependent.  Among Kv4 transcripts, the DRG expresses significant levels of Kv4.1 and Kv4.3 mRNAs.  Also, single small-medium diameter DRG neurons (~30 mm exhibit correlated frequent expression of mRNAs encoding Kv4.1 and Nav1.8, a known nociceptor marker.  In contrast, the expressions of Kv1.4 and Kv4.2 mRNAs at the whole-tissue and single-cell levels are relatively low and infrequent.  Kv4 protein expression in nociceptive DRG neurons was confirmed by immunohistochemistry, which demonstrates colocalization of Kv4.3 and Nav1.8, and negligible expression of Kv4.2.  Furthermore, specific dominant-negative suppression and overexpression strategies confirmed the contribution of Kv4 channels to IA in DRG neurons.  Contrasting the expression patterns of Kv4 channels in the central and peripheral nervous systems, we discuss possible functional roles of these channels in primary sensory neurons.

  17. From Microscopic to Macroscopic Descriptions of Cell Migration on Growing Domains

    KAUST Repository

    Baker, Ruth E.; Yates, Christian A.; Erban, Radek

    2009-01-01

    are studied, and correspondence with a macroscopic-level PDE describing the evolution of cell density is demonstrated. The individual-based models are formulated in terms of random walkers on a lattice. Domain growth provides an extra mathematical challenge

  18. New nuclear data set ABBN-90 and its testing on macroscopic experiments

    International Nuclear Information System (INIS)

    Kosh'cheev, V.N.; Manturov, G.N.; Nikolaev, M.N.; Rineyskiy, A.A.; Sinitsa, V.V.; Tsyboolya, A.M.; Zabrodskaya, S.V.

    1993-01-01

    The new group constant set ABBN-90 is developed now. It based on the FOND-2 evaluated neutron data library processed with the code GRUCON. Some results of the testing ABBN-90 set in different macroscopic experiments are presented. (author)

  19. Relationship Between Filler-Matrix Interface and Macroscopical Properties of Polymer Nanocomposites

    KAUST Repository

    Ventura, Isaac Aguilar

    2017-01-01

    The macroscopic properties of Multiwall Carbon Nanotube (MWCNT) polymer nano-composites and multiscale composites have been studied from a multifunctional standpoint. The objective is to understand and correlate the mechanisms in which the addition

  20. Equation-Free Analysis of Macroscopic Behavior in Traffic and Pedestrian Flow

    DEFF Research Database (Denmark)

    Marschler, Christian; Sieber, Jan; Hjorth, Poul G.

    2014-01-01

    Equation-free methods make possible an analysis of the evolution of a few coarse-grained or macroscopic quantities for a detailed and realistic model with a large number of fine-grained or microscopic variables, even though no equations are explicitly given on the macroscopic level. This will fac......Equation-free methods make possible an analysis of the evolution of a few coarse-grained or macroscopic quantities for a detailed and realistic model with a large number of fine-grained or microscopic variables, even though no equations are explicitly given on the macroscopic level....... This will facilitate a study of how the model behavior depends on parameter values including an understanding of transitions between different types of qualitative behavior. These methods are introduced and explained for traffic jam formation and emergence of oscillatory pedestrian counter flow in a corridor...

  1. Application of commercial MOSFET detectors for in vivo dosimetry in the therapeutic x-ray range from 80 kV to 250 kV

    International Nuclear Information System (INIS)

    Ehringfeld, Christian; Schmid, Susanne; Poljanc, Karin; Kirisits, Christian; Aiginger, Hannes; Georg, Dietmar

    2005-01-01

    The purpose of this study was to investigate the dosimetric characteristics (energy dependence, linearity, fading, reproducibility, etc) of MOSFET detectors for in vivo dosimetry in the kV x-ray range. The experience of MOSFET in vivo dosimetry in a pre-clinical study using the Alderson phantom and in clinical practice is also reported. All measurements were performed with a Gulmay D3300 kV unit and TN-502RDI MOSFET detectors. For the determination of correction factors different solid phantoms and a calibrated Farmer-type chamber were used. The MOSFET signal was linear with applied dose in the range from 0.2 to 2 Gy for all energies. Due to fading it is recommended to read the MOSFET signal during the first 15 min after irradiation. For long time intervals between irradiation and readout the fading can vary largely with the detector. The temperature dependence of the detector signal was small (0.3% deg. C -1 ) in the temperature range between 22 and 40 deg. C. The variation of the measuring signal with beam incidence amounts to ±5% and should be considered in clinical applications. Finally, for entrance dose measurements energy-dependent calibration factors, correction factors for field size and irradiated cable length were applied. The overall accuracy, for all measurements, was dominated by reproducibility as a function of applied dose. During the pre-clinical in vivo study, the agreement between MOSFET and TLD measurements was well within 3%. The results of MOSFET measurements, to determine the dosimetric characteristics as well as clinical applications, showed that MOSFET detectors are suitable for in vivo dosimetry in the kV range. However, some energy-dependent dosimetry effects need to be considered and corrected for. Due to reproducibility effects at low dose levels accurate in vivo measurements are only possible if the applied dose is equal to or larger than 2 Gy

  2. Application of commercial MOSFET detectors for in vivo dosimetry in the therapeutic x-ray range from 80 kV to 250 kV.

    Science.gov (United States)

    Ehringfeld, Christian; Schmid, Susanne; Poljanc, Karin; Kirisits, Christian; Aiginger, Hannes; Georg, Dietmar

    2005-01-21

    The purpose of this study was to investigate the dosimetric characteristics (energy dependence, linearity, fading, reproducibility, etc) of MOSFET detectors for in vivo dosimetry in the kV x-ray range. The experience of MOSFET in vivo dosimetry in a pre-clinical study using the Alderson phantom and in clinical practice is also reported. All measurements were performed with a Gulmay D3300 kV unit and TN-502RDI MOSFET detectors. For the determination of correction factors different solid phantoms and a calibrated Farmer-type chamber were used. The MOSFET signal was linear with applied dose in the range from 0.2 to 2 Gy for all energies. Due to fading it is recommended to read the MOSFET signal during the first 15 min after irradiation. For long time intervals between irradiation and readout the fading can vary largely with the detector. The temperature dependence of the detector signal was small (0.3% degrees C(-1)) in the temperature range between 22 and 40 degrees C. The variation of the measuring signal with beam incidence amounts to +/-5% and should be considered in clinical applications. Finally, for entrance dose measurements energy-dependent calibration factors, correction factors for field size and irradiated cable length were applied. The overall accuracy, for all measurements, was dominated by reproducibility as a function of applied dose. During the pre-clinical in vivo study, the agreement between MOSFET and TLD measurements was well within 3%. The results of MOSFET measurements, to determine the dosimetric characteristics as well as clinical applications, showed that MOSFET detectors are suitable for in vivo dosimetry in the kV range. However, some energy-dependent dosimetry effects need to be considered and corrected for. Due to reproducibility effects at low dose levels accurate in vivo measurements are only possible if the applied dose is equal to or larger than 2 Gy.

  3. Polyelectrolyte surfactant aggregates and their deposition on macroscopic surfaces

    International Nuclear Information System (INIS)

    Voisin, David

    2002-01-01

    cationically modified guar gums (of varying charge density) with two anionic surfactants: sodium lauryl (or dodecyl) ether sulfate [SLES] and sodium dodecyl sulfate [SDS], for various concentrations of the polyelectrolyte and added sodium chloride, at room temperature. The addition of sodium chloride has only a minor net effect on the CFC, but increases the CSC significantly. The interactions between the cationic polyelectrolyte and the surfactant have been studied in the one-phase regions, i.e. below the CFC and above the CSC, using different techniques. Surface tension, electrophoresis, light scattering and viscosimetry have been employed. In the two-phase region, the sedimented floe phase has been analysed and the flocculation has been investigated. Rheology of the floe phase has been studied, after a mild compression by centrifugation. The initial rate of flocculation has been determined, using stop-flow equipment. The growth and the structure of the flocs have been investigated by light scattering. The open-network flocs of polyelectrolyte-surfactant particles grow to ∼10's μm in size, prior to their eventual settling out. Other colloidal particles can be trapped within these large flocs, and the flocs can be used to transport these particles to a macroscopic surface. The deposition and the removal of such composite flocs on glass surfaces, under flow, have been studied using a flow cell device coupled with an optical microscope. Scanning electron microscopy and atomic force microscopy have also been employed. (author)

  4. Polyelectrolyte surfactant aggregates and their deposition on macroscopic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Voisin, David

    2002-07-01

    the CSC have been determined for mixtures of cationically modified guar gums (of varying charge density) with two anionic surfactants: sodium lauryl (or dodecyl) ether sulfate [SLES] and sodium dodecyl sulfate [SDS], for various concentrations of the polyelectrolyte and added sodium chloride, at room temperature. The addition of sodium chloride has only a minor net effect on the CFC, but increases the CSC significantly. The interactions between the cationic polyelectrolyte and the surfactant have been studied in the one-phase regions, i.e. below the CFC and above the CSC, using different techniques. Surface tension, electrophoresis, light scattering and viscosimetry have been employed. In the two-phase region, the sedimented floe phase has been analysed and the flocculation has been investigated. Rheology of the floe phase has been studied, after a mild compression by centrifugation. The initial rate of flocculation has been determined, using stop-flow equipment. The growth and the structure of the flocs have been investigated by light scattering. The open-network flocs of polyelectrolyte-surfactant particles grow to {approx}10's {mu}m in size, prior to their eventual settling out. Other colloidal particles can be trapped within these large flocs, and the flocs can be used to transport these particles to a macroscopic surface. The deposition and the removal of such composite flocs on glass surfaces, under flow, have been studied using a flow cell device coupled with an optical microscope. Scanning electron microscopy and atomic force microscopy have also been employed. (author)

  5. A continuous acceleration tube of ions under 200 KV; Un tube d'acceleration continue d'ions sous 200 KV

    Energy Technology Data Exchange (ETDEWEB)

    Mongodin, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1954-07-01

    The realization of an Van de Graaff accelerator required, for the preliminary studies, the construction of a small proton accelerator, functioning at 200 kV in order to resolve some parasitic effects inherent to the accelerators tubes. The aim of this report is to describe the different organs of the accelerator tube, to explain the operating system and to encode their characteristics. The report first presents the ion source and the beam buncher permitting to inject in the accelerator tube particles of about 9 kV and very batched in a thin beam of circular section. Then the study explain the tube characteristics considered like optic system. A method to obtain precise calculation of particle trajectories is exposed. Aberrations of the system were discussed and balance of the currents on all electrodes inside the tube for different regimes of working were provided. The influence of the residual pressure in the tube were explained. The report finally ends on a part of the fundamental problem of the straining occurring inside the tubes accelerators under high tension. (M.B.) [French] La realisation d n accelerateur du type Van de Graaff a necessite, entre autres etudes preliminaires, la construction d'un petit accelerateur de protons, fonctionnant sous 200 kV afin d'eclaircir certains effets parasites propres aux tubes accelerateurs. L'objet de ce rapport est de decrire les differents organes du tube accelerateur, d'en expliquer le fonctionnement et de chiffrer leurs caracteristiques. Le memoire presente d'abord la source d'ions et le canon permettant d'injecter dans le tube accelerateur des particules de 9 kV environ et bien groupees dans un faisceau fin de section circulaire. Puis il passe a l'etude du tube considere comme systeme optique. Une methode utilisee pour le calcul precis des trajectoires des particules y est exposee. Il aborde le probleme des aberrations de ce systeme et fournit par la suite le bilan des courants sur toutes les electrodes a l

  6. Effect of isovector coupling channel on the macroscopic part of the nuclear binding energy

    International Nuclear Information System (INIS)

    Haddad, S.

    2011-04-01

    The effect of the isovector coupling channel on the macroscopic part of the nuclear binding energy is determined utilizing the relativistic density dependent Thomas-Fermi approach for the calculation of the macroscopic part of the nuclear binding energy, and the dependency of this effect on the numbers of neutrons and protons is studied. The isovector coupling channel leads to increased nuclear binding energy, and this effect sharpens with growing excess of the number of neutrons on the number of protons. (author)

  7. Experimental observation of the quantum behavior of a macroscopic degree of freedom

    International Nuclear Information System (INIS)

    Devoret, M.H.; Martinis, J.M.; Esteve, D.

    1986-08-01

    At Berkeley a series of experiments have been performed, that demonstrates the quantum behavior of one macroscopic degree of freedom, namely the phase difference across a current biased Josephson junction. Here we will focus on the praticalities involved in such a demonstration. The emphasis is put on the particular procedures used to solve the two problems of noise shielding and parameter determination. To begin, a short description of the macroscopic system investigated, the current biased Josephson junction is given

  8. Multiscale Investigation on Biofilm Distribution and Its Impact on Macroscopic Biogeochemical Reaction Rates

    Science.gov (United States)

    Yan, Zhifeng; Liu, Chongxuan; Liu, Yuanyuan; Bailey, Vanessa L.

    2017-11-01

    Biofilms are critical locations for biogeochemical reactions in the subsurface environment. The occurrence and distribution of biofilms at microscale as well as their impacts on macroscopic biogeochemical reaction rates are still poorly understood. This paper investigated the formation and distributions of biofilms in heterogeneous sediments using multiscale models and evaluated the effects of biofilm heterogeneity on local and macroscopic biogeochemical reaction rates. Sediment pore structures derived from X-ray computed tomography were used to simulate the microscale flow dynamics and biofilm distribution in the sediment column. The response of biofilm formation and distribution to the variations in hydraulic and chemical properties was first examined. One representative biofilm distribution was then utilized to evaluate its effects on macroscopic reaction rates using nitrate reduction as an example. The results revealed that microorganisms primarily grew on the surfaces of grains and aggregates near preferential flow paths where both electron donor and acceptor were readily accessible, leading to the heterogeneous distribution of biofilms in the sediments. The heterogeneous biofilm distribution decreased the macroscopic rate of biogeochemical reactions as compared with those in homogeneous cases. Operationally considering the heterogeneous biofilm distribution in macroscopic reactive transport models such as using dual porosity domain concept can significantly improve the prediction of biogeochemical reaction rates. Overall, this study provided important insights into the biofilm formation and distribution in soils and sediments as well as their impacts on the macroscopic manifestation of reaction rates.

  9. The Effect of Phase-to-earth Faults on the Operating Conditions of a Separated 110 kV Grid Normally Operated with Effectively Earthed Neutral, and Temporarily Supplied from a Compensated 110 kV Grid

    Directory of Open Access Journals (Sweden)

    Wilhelm Rojewski

    2015-06-01

    Full Text Available The paper discusses the interoperability of the German compensated 110 kV grid and the Polish effectively earthed 110 kV grid. It is assumed that an area of one grid, separated from its power system, will be temporarily supplied from the other grid in its normal regime. Reference is made to the risks associated with phase-to-earth faults in grids so interconnected. Particular attention is paid to the working conditions of surge arresters and voltage transformers in the Polish 110 kV grid deprived of its neutral earthing when supplied from the German grid.

  10. MicroRNA-Mediated Downregulation of the Potassium Channel Kv4.2 Contributes to Seizure Onset

    Directory of Open Access Journals (Sweden)

    Christina Gross

    2016-09-01

    Full Text Available Seizures are bursts of excessive synchronized neuronal activity, suggesting that mechanisms controlling brain excitability are compromised. The voltage-gated potassium channel Kv4.2, a major mediator of hyperpolarizing A-type currents in the brain, is a crucial regulator of neuronal excitability. Kv4.2 expression levels are reduced following seizures and in epilepsy, but the underlying mechanisms remain unclear. Here, we report that Kv4.2 mRNA is recruited to the RNA-induced silencing complex shortly after status epilepticus in mice and after kainic acid treatment of hippocampal neurons, coincident with reduction of Kv4.2 protein. We show that the microRNA miR-324-5p inhibits Kv4.2 protein expression and that antagonizing miR-324-5p is neuroprotective and seizure suppressive. MiR-324-5p inhibition also blocks kainic-acid-induced reduction of Kv4.2 protein in vitro and in vivo and delays kainic-acid-induced seizure onset in wild-type but not in Kcnd2 knockout mice. These results reveal an important role for miR-324-5p-mediated silencing of Kv4.2 in seizure onset.

  11. Probabilitas Tegangan Sentuh Dan Tegangan Langkah Di Lokasi Rencana Gardu Induk 500 kV Antosari

    Directory of Open Access Journals (Sweden)

    Abdul Latif

    2016-06-01

    Full Text Available Semakin berkembangnya pertindustrian di Indonesia, maka kebutuhan daya listrik yang dibutuhkan semakin meningkat. Untuk memenuhi kebutuhan daya listrik tersebut pada tahun 2016, PT PLN (Persero merencanakan pembangunan GITET 500 kV Antosari. Pembangunan GITET 500 kV Antosari merupakan tindak lanjut dari rencana PT PLN (Persero yang akan menambah pasokan energi listrik ke Bali melalui sistem interkoneksi Jawa – Bali menggunakan jaringan transmisi SUTET 500 kV, dimulai dari GITET 500 kV Paiton dan akan sampai di GITET 500 kV Antosari. Untuk mengamankan gardu induk dari ancaman sambaran petir, salah satu cara yang digunakan adalah dengan mengamankan sistem perntanahan dilokasi gardu induk. Maka dipilih sistem pentanahan grid di lokasi rencana pembangunan Gardu Induk 500 kV Antosari. Penelitian dilakukan untuk menganalisis perbandingan ukuran luas pentanahan dengan kedalaman batang konduktor terhadap tahanan pentanahan grid, tegangan sentuh, tegangan langkah dan probabilitas timbulnya tegangan sentuh dan tegangan langkah. Data tahanan tanah yang didapatkan dari pengukuran secara langsung digunakan untuk mengetahui  nilai tahanan jenis tanah kemudian digunakan untuk menghitung tahanan pentanahan grid, tegangan sentuh, tegangan langkah dan probabilitas tegangan sentuh dan tegangan langkah. Perhitungan tahanan pentanahan grid menggunakan persamaan IEEE, Standard 80-2000 sedangkan untuk perhitungan tegangan sentuh dan tegangan langkah menggunakan IEEE, Standard 665-1995. Berdasarkan hasil penelitian di lokasi gardu induk untuk kondisi tanah basah dengan luas grid 3 m x 3 m dan kedalaman 5 m didapatkan nilai tahanan pentanahan grid 0,49 ohm dan nilai tegangan langkah 125 volt dengan probabilitas 0,72%. Sedangkan untuk kondisi tanah kering dengan luas grid 3 m x 3m dan kedalaman 5 didapatkan nilai tahanan pentanahan grid 1,11 ohm dan nilai tegangan langkah 281 volt dengan probabilitas 0,72%. Dari hasil analisis juga menunjukan dengan luas grid 3 m x 3

  12. Expression and function of Kv1.1 potassium channels in human atria from patients with atrial fibrillation.

    Science.gov (United States)

    Glasscock, Edward; Voigt, Niels; McCauley, Mark D; Sun, Qiang; Li, Na; Chiang, David Y; Zhou, Xiao-Bo; Molina, Cristina E; Thomas, Dierk; Schmidt, Constanze; Skapura, Darlene G; Noebels, Jeffrey L; Dobrev, Dobromir; Wehrens, Xander H T

    2015-09-01

    Voltage-gated Kv1.1 channels encoded by the Kcna1 gene are traditionally regarded as being neural-specific with no known expression or intrinsic functional role in the heart. However, recent studies in mice reveal low-level Kv1.1 expression in heart and cardiac abnormalities associated with Kv1.1-deficiency suggesting that the channel may have a previously unrecognized cardiac role. Therefore, this study tests the hypothesis that Kv1.1 channels are associated with arrhythmogenesis and contribute to intrinsic cardiac function. In intra-atrial burst pacing experiments, Kcna1-null mice exhibited increased susceptibility to atrial fibrillation (AF). The atria of Kcna1-null mice showed minimal Kv1 family ion channel remodeling and fibrosis as measured by qRT-PCR and Masson's trichrome histology, respectively. Using RT-PCR, immunocytochemistry, and immunoblotting, KCNA1 mRNA and protein were detected in isolated mouse cardiomyocytes and human atria for the first time. Patients with chronic AF (cAF) showed no changes in KCNA1 mRNA levels relative to controls; however, they exhibited increases in atrial Kv1.1 protein levels, not seen in paroxysmal AF patients. Patch-clamp recordings of isolated human atrial myocytes revealed significant dendrotoxin-K (DTX-K)-sensitive outward current components that were significantly increased in cAF patients, reflecting a contribution by Kv1.1 channels. The concomitant increases in Kv1.1 protein and DTX-K-sensitive currents in atria of cAF patients suggest that the channel contributes to the pathological mechanisms of persistent AF. These findings provide evidence of an intrinsic cardiac role of Kv1.1 channels and indicate that they may contribute to atrial repolarization and AF susceptibility.

  13. Heteromeric Kv7.2/7.3 channels differentially regulate action potential initiation and conduction in neocortical myelinated axons.

    Science.gov (United States)

    Battefeld, Arne; Tran, Baouyen T; Gavrilis, Jason; Cooper, Edward C; Kole, Maarten H P

    2014-03-05

    Rapid energy-efficient signaling along vertebrate axons is achieved through intricate subcellular arrangements of voltage-gated ion channels and myelination. One recently appreciated example is the tight colocalization of K(v)7 potassium channels and voltage-gated sodium (Na(v)) channels in the axonal initial segment and nodes of Ranvier. The local biophysical properties of these K(v)7 channels and the functional impact of colocalization with Na(v) channels remain poorly understood. Here, we quantitatively examined K(v)7 channels in myelinated axons of rat neocortical pyramidal neurons using high-resolution confocal imaging and patch-clamp recording. K(v)7.2 and 7.3 immunoreactivity steeply increased within the distal two-thirds of the axon initial segment and was mirrored by the conductance density estimates, which increased from ~12 (proximal) to 150 pS μm(-2) (distal). The axonal initial segment and nodal M-currents were similar in voltage dependence and kinetics, carried by K(v)7.2/7.3 heterotetramers, 4% activated at the resting membrane potential and rapidly activated with single-exponential time constants (~15 ms at 28 mV). Experiments and computational modeling showed that while somatodendritic K(v)7 channels are strongly activated by the backpropagating action potential to attenuate the afterdepolarization and repetitive firing, axonal K(v)7 channels are minimally recruited by the forward-propagating action potential. Instead, in nodal domains K(v)7.2/7.3 channels were found to increase Na(v) channel availability and action potential amplitude by stabilizing the resting membrane potential. Thus, K(v)7 clustering near axonal Na(v) channels serves specific and context-dependent roles, both restraining initiation and enhancing conduction of the action potential.

  14. A Common Structural Component for β-Subunit Mediated Modulation of Slow Inactivation in Different KV Channels

    DEFF Research Database (Denmark)

    Strutz-Seebohm, Nathalie; Henrion, Ulrike; Schmitt, Nicole

    2013-01-01

    Background/Aims: Potassium channels are tetrameric proteins providing potassium selective passage through lipid embedded proteinaceous pores with highest fidelity. The selectivity results from binding to discrete potassium binding sites and stabilization of a hydrated potassium ion in a central...... internal cavity. The four potassium binding sites, generated by the conserved TTxGYGD signature sequence are formed by the backbone carbonyls of the amino acids TXGYG. Residues KV1.5-Val481, KV4.3-Leu368 and KV7.1- Ile 313 represent the amino acids in the X position of the respective channels. Methods...

  15. Full Scale Test on a 100km, 150kV AC Cable

    DEFF Research Database (Denmark)

    Faria da Silva, Filipe Farria; Wiechowski, W.; Bak, Claus Leth

    2010-01-01

    phenomena is conducted. The cases analysed in this paper are: Zero-missing phenomenon, Ferranti effect, energisation transient, effect of the cable's connection in the busbar voltage and cable disconnection. For all the phenomena described in the paper measurement data are presented and it is verified......This paper presents some of the results obtained from the electrical measurements on a 99.7 km, 150 kV three-phase AC cable, connecting 215 MW offshore wind farm Horns Rev 2, located in Denmark west coast, to Denmark's 400 kV transmission network. The measurements were performed at nominal voltage...... if the obtained results are in accordance with the theory and also with simulations performed in PSCAD/EMTDC. With the exception of the cable disconnection, for all the remaining cases introduced in this paper the measurements confirmed the theoretical expectations. Depending on the cable disconnection sequence...

  16. Portable and wireless IV-curve tracer for >5 kV organic photovoltaic modules

    DEFF Research Database (Denmark)

    Garcia Valverde, Rafael; Chaouki-Almagro, Samir; Corazza, Michael

    2016-01-01

    voltage applications, the design is based on low cost components, battery-based isolated supply and wireless communication. A prototype has been implemented and field tested for characterization of different organic photovoltaic modules (OPV) made according to the infinity concept with a large number......The practical design of a wirelessly controlled portable IV-curve tracer based on a capacitive load is described. The design is optimized for the measurement of solar cell modules presenting a high open circuit voltage of up to 6 kV and a low short circuit current below 100 mA. The portable IV......-tracer allows for on-site/in-situ characterization of large modules under real operating conditions and enables fast detection of potential failure of anomalies in electrical behavior. Currently available electronic loads only handle voltages up to around 1 kV. To overcome cost and safety issues related to high...

  17. Design for a FET based 1 MHz, 10 kV pulse generator

    International Nuclear Information System (INIS)

    Barnes, M.J.; Wait, G.D.

    1995-08-01

    A pulse generator consisting of a coaxial cable and a high voltage modulator, incorporating two stacks of Field-Effect Transistor (FET) switches operating in ''push-pull'' mode, has been designed and built. The modulator generates a continuous, unipolar, pulse train at a fundamental frequency of 1 MHz and a magnitude of 10 kV. The rise and fall times of the pulses are less than 39 ns. The two stacks each utilize 14 FETS, which are individually rated at 1 kV. The design incorporates a low-loss coaxial cable on which pulses are stored. Extensive PSpice simulations have been carried out to evaluate various design options. Subsequent measurements on the prototype pulse generator confirm the PSpice predictions. This system is applicable for the kicker system at TRIUMF

  18. Internal services simulation control in 220/110kV power transformer station Mintia

    Science.gov (United States)

    Ciulica, D.; Rob, R.

    2018-01-01

    The main objectives in developing the electric transport and distribution networks infrastructure are satisfying the electric energy demand, ensuring the continuity of supply to customers, minimizing electricity losses in the transmission and distribution networks of public interest. This paper presents simulations in functioning of the internal services system 400/230 V ac in the 220/110 kV power transformer station Mintia. Using simulations in Visual Basic, the following premises are taken into consideration. All the ac consumers of the 220/110 kV power transformer station Mintia will be supplied by three 400/230 V transformers for internal services which can mutual reserve. In case of damaging at one transformer, the others are able to assume the entire consumption using automatic release of reserves. The simulation program studies three variants in which the continuity of supply to customers are ensured. As well, by simulations, all the functioning situations are analyzed in detail.

  19. JAERI 200 kV electron gun with an NEA-GaAs photocathode

    International Nuclear Information System (INIS)

    Nishitani, Tomohiro; Minehara, Eisuke J.; Hajima, Ryoichi; Nagai, Ryoji; Sawamura, Masaru; Nishimori, Nobuyuki; Kikuzawa, Nobuhiro; Yamauchi, Toshihiko

    2004-01-01

    The photocathode DC-gun with high average current, low beam emittance and long operational lifetime is considered to be indispensable for ERL-FEL. We have started the development program of a 200 keV electron gun with the NEA-GaAs photocathode for the first time in JAERI. In order to long an NEA surface lifetime, the JAERI 200 kV electron gun system consists of a 200 kV DC-gun chamber on extreme high vacuum condition and an NEA activation chamber with load-lock system. We report the goal of photocathode DC-gun R and D and the schedule of a developmental program. (author)

  20. 80 kV electrostatic wire septum for AmPS

    International Nuclear Information System (INIS)

    Linden, A. van der; Bijleveld, J.H.M.; Rookhuizen, H.B.; Bruinsma, P.J.T.; Heine, E.; Lassing, P.; Prins, E.

    1992-01-01

    The Amsterdam Pulse Stretcher (AmPS) ring aims at a 100% duty cycle operation by means of slow extraction of injected electron beam pulses of 2.1 μs. In the extraction process of the AmPS, the extracted beam is intercepted from the circulating beam by the 1 m long electrostatic wire septum. For a bending angle of 4.4 mrad the maximum anode voltage is 80 kV. Care has been given to the electric field distribution at the entrance and exit of the septum and to the insulators, required to support the anode. Prototype tests have been successful up to an anode voltage of 120 kV. (R.P.) 9 refs.; 5 figs

  1. Design and development of a high-power, 500 kV pulsed line

    International Nuclear Information System (INIS)

    Nicolas, A.

    A study was made of very high voltage (500 kV) pulse production for 50 ns at half height. A coaxial line was coupled to a Marx generator for obtaining the pulses on an impedance-adapted electron diode. The maximum power obtained was 6.4 x 10 10 W with a current front in the diode of about 30 ns (80 ns pulse length at half height)

  2. Method of selecting optimum cross arm lengths for a 750 kV transmission line

    Energy Technology Data Exchange (ETDEWEB)

    Aleksandrov, G N; Olorokov, V P

    1965-01-01

    A method is presented, based on both technical and economic considerations, for selecting cross arm lengths for intermediate poles of power transmission lines according to the effects of internal overvoltage, methods from probability theory and mathematical statistics employed. The problem of optimum pole size is considered in terms of the effect of internal overvoltages for a prescribed maximum level of 2.1 PU currently used in the USSR for the design of 750 kV lines.

  3. Preliminary design of a 100 Hz, 350 kV short pulse generator

    International Nuclear Information System (INIS)

    Rohwein, G.J.; Buttram, M.T.

    1977-06-01

    This report describes a 350 kV pulser designed to generate 100 ns square pulses with 300 joules total energy at a pulse repetition frequency of 100 per second. This design incorporates a transformer charged helical coaxial pulse forming line. The considerations leading to this design are presented together with results from prototype experiments. The pulser which is presently in the construction and testing phase is described in detail. The pulser will be used for electron beam acceleration

  4. STUDY ON PERFORMANCE OF 21M 132kV TRANSMISSION TOWER WITH MEDIUM WIND INTENSITY

    OpenAIRE

    V. LAKSHMI; A. RAJAGOPALA RAO

    2012-01-01

    Electric Power is today playing an increasingly important role in the life of the community. In the electric power system the production and transmission of power are two predominant factors. For the purpose of transmission of electricity towers are the main medium with some wires at required distances and altitudes. The remotehydroelectric power plants have given rise to the need for extra high voltage. Prior to 1950, 150 kV electric transmission lines were considered and still higher voltag...

  5. Regulation System for the 18 kV/90 Mvar Compensators

    CERN Document Server

    Burdet, G

    2001-01-01

    Two 18 kV/90 Mvar static compensators are involved to stabilise the voltage, filter the harmonics and compensate the reactive power generated by the power converters used to supply the SPS accelerator magnets. The in-house hardware and software used by the regulation systems, difficult to maintain and upgrade, shall be renovated. Industrial solution based on PLC will be implemented. This paper describes the future system and its integration to the Electrical Network Supervisor.

  6. Optimizing monoscopic kV fluoro acquisition for prostate intrafraction motion evaluation

    International Nuclear Information System (INIS)

    Adamson, Justus; Wu Qiuwen

    2009-01-01

    Monoscopic kV imaging during radiotherapy has been recently implemented for prostate intrafraction motion evaluation. However, the accuracy of 3D localization techniques from monoscopic imaging of prostate and the effect of acquisition parameters on the 3D accuracy have not been studied in detail, with imaging dose remaining a concern. In this paper, we investigate methods to optimize the kV acquisition parameters and imaging protocol to achieve improved 3D localization and 2D image registration accuracy for minimal imaging dose. Prostate motion during radiotherapy was simulated using existing cine-MRI measurements, and was used to investigate the accuracy of various 3D localization techniques and the effect of the kV acquisition protocol. We also investigated the relationship between mAs and the accuracy of the 2D image registration for localization of fiducial markers and we measured imaging dose for a 30 cm diameter phantom to evaluate the necessary dose to achieve acceptable image registration accuracy. Simulations showed that the error in assuming the shortest path to localize the prostate in 3D using monoscopic imaging during a typical IMRT fraction will be less than ∼1.5 mm for 95% of localizations, and will also depend on prostate motion distribution, treatment duration and image acquisition and treatment protocol. Most uncertainty cannot be reduced from higher imaging frequency or acquiring during gantry rotation between beams. Measured maximum surface dose to the cylindrical phantom from monoscopic kV intrafraction acquisitions varied between 0.4 and 5.5 mGy, depending on the acquisition protocol, and was lower than the required dose for CBCT (21.1 mGy). Imaging dose can be lowered by ∼15-40% when mAs is optimized with acquisition angle. Images acquired during MV beam delivery require increased mAs to obtain the same level of registration accuracy, with mAs/registration increasing roughly linearly with field size and dose rate.

  7. Protection system for 11kV network using arc noise

    International Nuclear Information System (INIS)

    Burdi, M.K.; Memon, A.S.; Shaikh, S.A.

    2000-01-01

    Extensive research work is being done on protecting devices for 11KV network using arc noise and fault noise frequencies in relay to operate a circuit breaker; The relay works on the principle of detecting fault and extracting voltage signal output from the noise frequencies across filter. The voltage development without amplification, is enough to operate the circuit breaker. Sensitivity of the circuit breaker. In this paper design, operation and application of the relay are described. (author)

  8. AC transmission, with very high voltages and the 750 kV line

    Energy Technology Data Exchange (ETDEWEB)

    Bocker, H

    1964-01-01

    The economic case for adoption of extra-high voltages for transmitting electric power over distances of the order of 1000 km is discussed. Some special technical developments for solving the problems attached to such high voltages are briefly discussed, particularly in the fields of switching and transients suppression. The first 750-kV projects in Canada and Russia are mentioned. Equipment, e.g., bushings, transformers, etc., operating at such voltages are illustrated.

  9. Diagnostics system for the 67 MJ, 50 kV pulsed power capacitor bank

    Energy Technology Data Exchange (ETDEWEB)

    Galakhov, I V; Gasheev, A S; Gruzin, I A; Gudov, S N; Murugov, V M; Osin, V A; Pankratov, V I; Pegoev, I N [All-Russian Scientific Research Inst. of Experimental Physics, Sarov (Russian Federation)

    1997-12-31

    The diagnostics system is designed for charging and discharging to the load of the large 67 MJ and 50 kV capacitor bank for the iodine laser pulse power of ISKRA-5 facility. Discharging diagnostics of the capacitor bank uses a technique to measure a sequence of times between representative discharge events for 665 discharge circuits of the bank. Benefits of the measurement techniques are discussed. (author). 3 figs., 3 refs.

  10. Studi Keamanan dan Keandalan Suplai Sistem Kelistrikan Bali Sesuai Rencana Operasi SUTET 500 kV

    Directory of Open Access Journals (Sweden)

    Bawa Adiputra

    2014-12-01

    Full Text Available Kondisi eksisting kelistrikan Bali hingga tahun 2013 disuplai oleh tiga pembangkit tenaga listrik dan sebuah sistem interkoneksi Jamali dengan keseluruhan daya suplai sebesar 676 MW. Berdasarkan peramalan beban sistem Bali 2013-2030 diperoleh rata-rata pertumbuhan beban 6,61%. Berdasarkan hal tersebut PT PLN (Persero merencanakan penambahan pasokan daya listrik ke pulau Bali dengan penambahan kabel laut, suplai melalui SUTET 500 kV interkoneksi Jawa-Bali, serta pembangunan PLTU Celukan Bawang 980 MW. Dengan beroperasinya unit-unit tersebut diperlukan analisis keamanan suplai sistem kelistrikan Bali, dengan dua skenario. Skenario 1 yaitu sistem Bali hanya menerima pasokan dari PLTU Celukan Bawang pada tahun 2016 sebesar 380 MW. Skenario 2, PLTU Celukan Bawang beroperasi sebesar 380 MW tahun 2016, kemudian pada tahun 2020 dan 2022 menambah daya masing-masing 300 MW. Selain analisis keamanan suplai dilakukan juga analisis keandalan dengan beroperasinya SUTET 500 kV di Bali. Analisis keandalan SUTET 500 kV menggunakan tiga skenario. Skenario 1 SUTET beroperasi dari Paiton sampai di GITET Gilimanuk, Skenario 2 SUTET beroperasi dari PAITON sampai di GITET New Kapal, dan Skenario 3 SUTET beroperasi dari Paiton sampai di GITET Kapal. Dari hasil analisis keamanan suplai diperoleh skenario 1, pada tahun 2022 beban puncak mencapai 1304,10 MW dan pada kondisi N-1 mengalami krisis daya listrik -48,3 MW. Skenario 2, pada tahun 2028 dengan beban puncak 1862,60 MW dan pada kondisi N-1 mengalami krisis daya listrik -6,8 MW. Sedangkan analisis keandalan beroperasinya SUTET 500 kV di Bali diperoleh: Skenario 1 nilai SAIFI = 2,0 kali/km/tahun dan nilai SAIDI = ±10 menit/tahun, Skenario 2 nilai SAIFI = 3,1 kali/km/tahun dan nilai SAIDI = ±15 menit/tahun, Skenario 3 nilai SAIFI = 3,3 kali/km/tahun dan nilai SAIDI = ±17 menit/tahun.

  11. Diagnostics system for the 67 MJ, 50 kV pulsed power capacitor bank

    International Nuclear Information System (INIS)

    Galakhov, I.V.; Gasheev, A.S.; Gruzin, I.A.; Gudov, S.N.; Murugov, V.M.; Osin, V.A.; Pankratov, V.I.; Pegoev, I.N.

    1996-01-01

    The diagnostics system is designed for charging and discharging to the load of the large 67 MJ and 50 kV capacitor bank for the iodine laser pulse power of ISKRA-5 facility. Discharging diagnostics of the capacitor bank uses a technique to measure a sequence of times between representative discharge events for 665 discharge circuits of the bank. Benefits of the measurement techniques are discussed. (author). 3 figs., 3 refs

  12. Aberration-corrected STEM/TEM imaging at 15 kV

    International Nuclear Information System (INIS)

    Sasaki, Takeo; Sawada, Hidetaka; Hosokawa, Fumio; Sato, Yuta; Suenaga, Kazu

    2014-01-01

    The performance of aberration-corrected (scanning) transmission electron microscopy (S/TEM) at an accelerating voltage of 15 kV was evaluated in a low-voltage microscope equipped with a cold-field emission gun and a higher-order aberration corrector. Aberrations up to the fifth order were corrected by the aberration measurement and auto-correction system using the diffractogram tableau method in TEM and Ronchigram analysis in STEM. TEM observation of nanometer-sized particles demonstrated that aberrations up to an angle of 50 mrad were compensated. A TEM image of Si[110] exhibited lattice fringes with a spacing of 0.192 nm, and the power spectrum of the image showed spots corresponding to distances of 0.111 nm. An annular dark-field STEM image of Si[110] showed lattice fringes of (111) and (22¯0) planes corresponding to lattice distances of 0.314 nm and 0.192 nm, respectively. At an accelerating voltage of 15 kV, the developed low-voltage microscope achieved atomic-resolution imaging with a small chromatic aberration and a large uniform phase. - Highlights: • Aberration-corrected STEM/TEM imaging at 15 kV demonstrated lattice fringes of Si[110] single crystal with a spacing of 0.192 nm. • To achieve this performance at a lower accelerating voltage, uniform phase area over 50 mrad is mandatory in Ronchigram and Diffractogram tableau. • This means a higher-order aberration of six-fold astigmatism should be compensated. • In addition, decreasing the effect of chromatic aberration plays an important role for improving the performance of linear scattering component at 15 kV TEM

  13. Physically-based modeling of the cyclic macroscopic behaviour of metals

    International Nuclear Information System (INIS)

    Sauzay, M.; Evrard, P.; Steckmeyer, A.; Ferrie, E.

    2010-01-01

    Grain size seems to have only a minor influence on the cyclic strain strain curves (CSSCs) of metallic polycrystals of medium to high stacking fault energy (SFE). That is why many authors tried to deduce the macroscopic CSSCs curves from the single crystals ones. Either crystals oriented for single slip or crystals oriented for multiple slip could be considered. In addition, a scale transition law should be used (from the grain scale to the macroscopic scale). Authors generally used either the Sachs rule (homogeneous single slip) or the Taylor one (homogeneous plastic strain, multiple slip). But the predicted macroscopic CSSCs do not generally agree with the experimental data for metals and alloys, presenting various SFE values. In order to avoid the choice of a particular scale transition rule, many finite element (FE) computations have been carried out using meshes of polycrystals including more than one hundred grains without texture. This allows the study of the influence of the crystalline constitutive laws on the macroscopic CSSCs. Activation of a secondary slip system in grains oriented for single slip is either allowed or hindered (slip planarity), which affects strongly the macroscopic CSSCs. The more planar the slip, the higher the predicted macroscopic stress amplitudes. If grains oriented for single slip obey slip planarity and two crystalline CSSCs are used (one for single slip grains and one for multiple slip grains), then the predicted macroscopic CSSCs agree well with experimental data provided the SFE is not too low (316L, copper, nickel, aluminium). Finally, the incremental self-consistent Hill-Hutchinson homogenization model is used for predicting CSS curves and partially validated with respect to the curves computed by the FE method. (authors)

  14. A Study of Electromagnetic Radiation of Corona Discharge Near 500-Kv Electric Installations

    International Nuclear Information System (INIS)

    Korzhov, A. V.; Okrainskaya, I. S.; Sidorov, A. I.; Kufel'd, V. D.

    2004-01-01

    Data on the spectral composition and intensity of electromagnetic radiation of corona discharge are obtained in an experimental study performed on the outdoor switchgear of the Shagol 500-kV substation of the Chelyabinsk Enterprise of Trunk Transmission Grids and under a 500-kV Shagol - Kozyrevo overhead transmission line. The electromagnetic environment on the territory of the 500-kV outdoor switchgear is shown to be determined by narrow-band radiations (harmonics of the frequency of electric supply) and wide-band radiations due to corona discharges of high-voltage sources. This means that the personnel experience the action of a commercial-frequency electric field and electromagnetic radiation of a quite wide range, which is not allowed for by the existing guidelines. It is recommended to continue the study in cooperation with medical institutions in order to create guidelines that would allow for the joint action of commercial-frequency electric field and electromagnetic radiation and for the voltage in the line, the current load, the meteorological situation, and other factors

  15. Clicked bis-PEG-peptide conjugates for studying calmodulin-Kv7.2 channel binding.

    Science.gov (United States)

    Bonache, M Angeles; Alaimo, Alessandro; Malo, Covadonga; Millet, Oscar; Villarroel, Alvaro; González-Muñiz, Rosario

    2014-11-28

    The recombinant Kv7.2 calmodulin (CaM) binding site (Q2AB CaMBD) shows a high tendency to aggregate, thus complicating biochemical and structural studies. To facilitate these studies we have conceived bis-PEG-peptide CaMBD-mimetics linking helices A and B in single, easy to handle molecules. Short PEG chains were selected as spacers between the two peptide molecules, and a Cu(i)-catalyzed cycloaddition (CuAAC) protocol was used to assemble the final bis-PEG-peptide conjugate, by the convenient functionalization of PEG arms with azide and alkyne groups. The resulting conjugates, with a certain helical character in TFE solutions (CD), showed nanomolar affinity in a fluorescence CaM binding in vitro assay, higher than just the sum of the precursor PEG-peptide affinities, thus validating our design. The approach to these first described examples of Kv7.2 CaMBD-mimetics could pave the way to chimeric conjugates merging helices A and B from different Kv7 subunits.

  16. Measurements on a FET based 1 MHz, 10 kV pulse generator

    International Nuclear Information System (INIS)

    Wait, G.D.; Barnes, M.J.

    1995-08-01

    A prototype pulser, which incorporates thirty-two 1 kV Field-Effect Transistor (FET) modules, has been built and tested at TRIUMF. The pulser has been developed for application in a scheme for pulsed extraction from the TRIUMF 500 MeV cyclotron. Deflection of the beam will be provided by an electric field between a set of 1 in long deflector plates. The pulser generates a continuous, unipolar, pulse train at a fundamental frequency of approximately 1 MHz and a magnitude of 10 kV. The pulses have 38 ns rise and fall times and are stored on a low-loss coaxial cable which interconnects the pulse generator and the deflector plates. The circuit performance was evaluated with the aid of PSpice in the design stage and confirmed by measurements on the prototype. Temperature measurements have been performed on 1 kV FET modules under DC conditions and compared with temperatures under operating conditions to ensure that switching losses are acceptable. Results of various measurements are presented and compared with simulations

  17. Measurements on a FET based 1 MHz, 10 kV pulse generator

    International Nuclear Information System (INIS)

    Wait, G.D.; Barnes, M.J.

    1995-08-01

    A prototype pulser, which incorporates thirty-two 1 kV Field-Effect Transistor (FET) modules, has been built and tested at TRIUMF. The pulser has been developed for application in a scheme for pulsed extraction from the TRIUMF 500 MeV cyclotron. Deflection of the beam will be provided by an electric field between a set of 1 m long deflector plates. The pulser generates a continuous unipolar, pulse train at a fundamental frequency of approximately 1 MHz and a magnitude of 10 kV. The pulses have 38 ns rise and fall times and are stored on a low-loss coaxial cable which interconnects the pulse generator and the deflector plates. The circuit performance was evaluated with the aid of PSpice in the design stage and confirmed by measurements on the prototype. Temperature measurements have been performed on 1 kV FET modules under DC conditions and compared with temperatures under operating conditions to ensure that switching losses are acceptable. Results of various measurements are presented and compared with simulations. (author)

  18. KV7 Channels Regulate Firing during Synaptic Integration in GABAergic Striatal Neurons

    Directory of Open Access Journals (Sweden)

    M. Belén Pérez-Ramírez

    2015-01-01

    Full Text Available Striatal projection neurons (SPNs process motor and cognitive information. Their activity is affected by Parkinson’s disease, in which dopamine concentration is decreased and acetylcholine concentration is increased. Acetylcholine activates muscarinic receptors in SPNs. Its main source is the cholinergic interneuron that responds with a briefer latency than SPNs during a cortical command. Therefore, an important question is whether muscarinic G-protein coupled receptors and their signaling cascades are fast enough to intervene during synaptic responses to regulate synaptic integration and firing. One of the most known voltage dependent channels regulated by muscarinic receptors is the KV7/KCNQ channel. It is not known whether these channels regulate the integration of suprathreshold corticostriatal responses. Here, we study the impact of cholinergic muscarinic modulation on the synaptic response of SPNs by regulating KV7 channels. We found that KV7 channels regulate corticostriatal synaptic integration and that this modulation occurs in the dendritic/spines compartment. In contrast, it is negligible in the somatic compartment. This modulation occurs on sub- and suprathreshold responses and lasts during the whole duration of the responses, hundreds of milliseconds, greatly altering SPNs firing properties. This modulation affected the behavior of the striatal microcircuit.

  19. Improvement of the 400 kV linac electron source of AmPS

    International Nuclear Information System (INIS)

    Kroes, F.B.; Beuzekom, M.G. van; Dobbe, N.J.; Es, J.T. van; Jansweijer, P.P.M.; Kruijer, A.H.; Luigjes, G.; Sluijk, T.G.B.

    1992-01-01

    An existing linac (MEA) injects electrons into the Amsterdam Pulse Stretcher (AmPS) ring. The linac's peak current increases from 20 to 80 mA. This requires the modification of the 400 kV low emittance gun. The fourfold increase of the peak current is obtained by doubling both the gun perveance (new gun part) and the pulsed extractor voltage. To obtain optimum beam quality over this increased current range, the hot deck electronics has been exchanged by a fast high voltage FET switching supply. A built-in microprocessor, coupled to the local computer by optical fibers, is used to monitor and control the gun parameters. The 5 kV gun extractor voltage pulse shape can be monitored by means of an analog fibre transducer with build in calibration. Finally, in order to improve the energy stability of the accelerated electrons, a serial electron-tube stabilizer was added to the 400 kV DC power supply. (K.A.) 4 refs.; 6 figs

  20. A 120kV IGBT modulator for driving a Pierce electron gun

    International Nuclear Information System (INIS)

    Earley, Lawrence M.; Brown, Richard W.; Carlson, Randolph L.; Ferguson, Patrick; Haynes, William B.; Kirbie, Hugh C.; Russell, Steven J.; Sigler, Floyd E.; Smirnova, Evgenya I.; Wheat, Robert M. Jr.

    2004-01-01

    An IGBT modulator has been developed to drive a 120 kV, 23 A Pierce electron gun. The modulator is capable of producing pulses up to 10 μs in width at repetition rates up to 10Hz with no active reset. The pulse rise time on the electron gun will be approximately 2 μs and the remaining 8 μs of flattop is tuned to have a ripple of less than 1 percent rms. The modulator technology was developed from a previous 50 kV prototype. The modulator consists of six boards, each with one EUPEC IGBT that drives a single common step-up transformer wound on METGLAS 2605SC cores. The six transformer cores share a common bi-filar output secondary winding. The modulator uses a fiber optic trigger system and has a high voltage cable output with an epoxy receptacle on the oil end and a ceramic receptacle on the vacuum end. The 120 kV electron gun was manufactured by MDS Co. and will be used to generate sheet electron beams from the standard pencil beam produced by the Pierce electron gun.

  1. Implication of novel thiazolo-thiophene derivative (MCD-KV-10) for management of asthma.

    Science.gov (United States)

    Patil, Dhiraj; Dash, Ranjeet Prasad; Thakur, Sandeep Kumar; Pandya, Amit N; Venkatesh, P; Vasu, Kamala K; Nivsarkar, Manish

    2015-04-01

    Asthma is multifaceted disease where many targets contribute towards its development and progression. Among these, adenosine receptor subtypes play a major role. MCD-KV-10, a novel thiazolo-thiophene was designed and evaluated pre-clinically for its implication in management of asthma. This compound showed good affinity and selectivity towards A(2A)/A3 adenosine receptor (AR) subtypes. Furthermore, MCD-KV-10 was evaluated for in vitro lipoxygenase inhibition activity; in vivo mast cell stabilization potential and in vivo anti-asthmatic activity was done in ovalbumin-induced airway inflammation model in guinea pigs. The compound showed good (>57%) inhibition of lipoxygenase enzyme and also effectively protected mast cell degranulation (>63%). The compound showed good anti-asthmatic activity as inferred from the in vivo studies. These results indicate that MCD-KV-10 has an inhibitory effect on airway inflammation. Though, we have identified a potential candidate for management of asthma, further mechanistic studies are needed.

  2. 250 kV 6 mA compact Cockcroft-Walton high-voltage power supply

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Zhan-Wen; Su, Xiao-Dong; Wei, Zhen; Huang, Zhi-Wu; Miao, Tian-You; Su, Tong-Ling [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Lu, Xiao-Long; Wang, Jun-Run; Yao, Ze-En, E-mail: zeyao@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Engineering Research Center for Neutron Application, Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

    2016-08-15

    A compact power supply system for a compact neutron generator has been developed. A 4-stage symmetrical Cockcroft-Walton circuit is adopted to produce 250 kV direct current high-voltage. A 2-stage 280 kV isolation transformer system is used to drive the ion source power supply. For a compact structure, safety, and reliability during the operation, the Cockcroft-Walton circuit and the isolation transformer system are enclosed in an epoxy vessel containing the transformer oil whose size is about ∅350 mm × 766 mm. Test results indicate that the maximum output voltage of the power supply is 282 kV, and the stability of the output voltage is better than 0.63% when the high voltage power supply is operated at 250 kV, 6.9 mA with the input voltage varying ±10%.

  3. Kv4.2 knockout mice display learning and memory deficits in the Lashley maze [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Gregory D. Smith

    2016-10-01

    Full Text Available Background: Potassium channels have been shown to be involved in neural plasticity and learning. Kv4.2 is a subunit of the A-type potassium channel. Kv4.2 channels modulate excitability in the dendrites of pyramidal neurons in the cortex and hippocampus. Deletion of Kv4.2 results in spatial learning and conditioned fear deficits; however, previous studies have only examined deletion of Kv4.2 in aversive learning tests. Methods: For the current study, we used the Lashley maze as an appetitive learning test. We examined Kv4.2 wildtype (WT and knockout (KO mice in the Lashley maze over 4 days during adulthood. The first day consisted of habituating the mice to the maze. The mice then received five trials per day for the next 3 days. The number of errors and the time to the goal box was recorded for each trial. The goal box contained a weigh boat with an appetitive reward (gelatin with sugar. There was an intertrial interval of 15 minutes. Results: We found that Kv4.2 KO mice committed more errors across the trials compared to the WT mice p<0.001. There was no difference in the latency to find the goal box over the period. Discussion: Our finding that deletion of Kv4.2 resulted in more errors in the Lashley maze across 15 trials contribute to a growing body of evidence that Kv4.2 channels are significantly involved in learning and memory.

  4. Kv4.2 knockout mice display learning and memory deficits in the Lashley maze [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Gregory D. Smith

    2017-02-01

    Full Text Available Background: Potassium channels have been shown to be involved in neural plasticity and learning. Kv4.2 is a subunit of the A-type potassium channel. Kv4.2 channels modulate excitability in the dendrites of pyramidal neurons in the cortex and hippocampus. Deletion of Kv4.2 results in spatial learning and conditioned fear deficits; however, previous studies have only examined deletion of Kv4.2 in aversive learning tests. Methods: For the current study, we used the Lashley maze as an appetitive learning test. We examined Kv4.2 wildtype (WT and knockout (KO mice in the Lashley maze over 4 days during adulthood. The first day consisted of habituating the mice to the maze. The mice then received five trials per day for the next 3 days. The number of errors and the time to the goal box was recorded for each trial. The goal box contained a weigh boat with an appetitive reward (gelatin with sugar. There was an intertrial interval of 15 minutes. Results: We found that Kv4.2 KO mice committed more errors across the trials compared to the WT mice p<0.001. There was no difference in the latency to find the goal box over the period. Discussion: Our finding that deletion of Kv4.2 resulted in more errors in the Lashley maze across 15 trials contribute to a growing body of evidence that Kv4.2 channels are significantly involved in learning and memory.

  5. Laparoscopic vs open total mesorectal excision for rectal cancer: an evaluation of the mesorectum's macroscopic quality.

    Science.gov (United States)

    Breukink, S O; Grond, A J K; Pierie, J P E N; Hoff, C; Wiggers, T; Meijerink, W J H J

    2005-03-01

    Next to surgical margins, yield of lymph nodes, and length of bowel resected, macroscopic completeness of mesorectal excision may serve as another quality control of total mesorectal excision (TME). In this study, the macroscopic completeness of laparoscopic TME was evaluated. A series of 25 patients with rectal cancer were managed laparoscopically (LTME) and included in this study. The pathologic specimens of the LTME group were prospectively examined and matched with a historical group of resection specimens from patients who had undergone open TME (OTME). The two groups were matched for gender and type of resection (low anterior or abdominoperineal resection). Special care was given to the macroscopic judgment concerning the completeness of the mesorectum. A three-grade scoring system showed no differences between the LTME and OTME groups. The current study supports the hypothesis that oncologic resection using laparoscopic TME is feasible and adequate.

  6. The effect of interlayer adhesion on the mechanical behaviors of macroscopic graphene oxide papers.

    Science.gov (United States)

    Gao, Yun; Liu, Lu-Qi; Zu, Sheng-Zhen; Peng, Ke; Zhou, Ding; Han, Bao-Hang; Zhang, Zhong

    2011-03-22

    High mechanical performances of macroscopic graphene oxide (GO) papers are attracting great interest owing to their merits of lightweight and multiple functionalities. However, the loading role of individual nanosheets and its effect on the mechanical properties of the macroscopic GO papers are not yet well understood. Herein, we effectively tailored the interlayer adhesions of the GO papers by introducing small molecules, that is, glutaraldehyde (GA) and water molecules, into the gallery regions. With the help of in situ Raman spectroscopy, we compared the varied load-reinforcing roles of nanosheets, and further predicted the Young's moduli of the GO papers. Systematic mechanical tests have proven that the enhancement of the tensile modulus and strength of the GA-treated GO paper arose from the improved load-bearing capability of the nanosheets. On the basis of Raman and macroscopic mechanical tests, the influences of interlayer adhesions on the fracture mechanisms of the strained GO papers were inferred.

  7. Preparation of rock samples for measurement of the thermal neutron macroscopic absorption cross-section

    International Nuclear Information System (INIS)

    Czubek, J.A.; Burda, J.; Drozdowicz, K.; Igielski, A.; Kowalik, W.; Krynicka-Drozdowicz, E.; Woznicka, U.

    1986-03-01

    Preparation of rock samples for the measurement of the thermal neutron macroscopic absorption cross-section in small cylindrical two-region systems by a pulsed technique is presented. Requirements which should be fulfilled during the preparation of the samples due to physical assumptions of the method are given. A cylindrical vessel is filled with crushed rock and saturated with a medium strongly absorbing thermal neutrons. Water solutions of boric acid of well-known macroscopic absorption cross-section are used. Mass contributions of the components in the sample are specified. This is necessary for the calculation of the thermal neutron macroscopic absorption cross-section of the rock matrix. The conditions necessary for assuring the required accuracy of the measurement are given and the detailed procedure of preparation of the rock sample is described. (author)

  8. Mechanical Behaviour of Materials Volume 1 Micro- and Macroscopic Constitutive Behaviour

    CERN Document Server

    François, Dominique; Zaoui, André

    2012-01-01

    Advances in technology are demanding ever-increasing mastery over the materials being used: the challenge is to gain a better understanding of their behaviour, and more particularly of the relations between their microstructure and their macroscopic properties.   This work, of which this is the first volume, aims to provide the means by which this challenge may be met. Starting from the mechanics of deformation, it develops the laws governing macroscopic behaviour – expressed as the constitutive equations – always taking account of the physical phenomena which underlie rheological behaviour. The most recent developments are presented, in particular those concerning heterogeneous materials such as metallic alloys, polymers and composites. Each chapter is devoted to one of the major classes of material behaviour.   As the subtitles indicate, Volume 1 deals with micro- and macroscopic constitutive behaviour and Volume 2 with damage and fracture mechanics. A third volume will be devoted to exercises and the...

  9. Estimation of macroscopic elastic characteristics for hierarchical anisotropic solids based on probabilistic approach

    Science.gov (United States)

    Smolina, Irina Yu.

    2015-10-01

    Mechanical properties of a cable are of great importance in design and strength calculation of flexible cables. The problem of determination of elastic properties and rigidity characteristics of a cable modeled by anisotropic helical elastic rod is considered. These characteristics are calculated indirectly by means of the parameters received from statistical processing of experimental data. These parameters are considered as random quantities. With taking into account probable nature of these parameters the formulas for estimation of the macroscopic elastic moduli of a cable are obtained. The calculating expressions for macroscopic flexural rigidity, shear rigidity and torsion rigidity using the macroscopic elastic characteristics obtained before are presented. Statistical estimations of the rigidity characteristics of some cable grades are adduced. A comparison with those characteristics received on the basis of deterministic approach is given.

  10. Hybrid methods for witnessing entanglement in a microscopic-macroscopic system

    International Nuclear Information System (INIS)

    Spagnolo, Nicolo; Vitelli, Chiara; Paternostro, Mauro; De Martini, Francesco; Sciarrino, Fabio

    2011-01-01

    We propose a hybrid approach to the experimental assessment of the genuine quantum features of a general system consisting of microscopic and macroscopic parts. We infer entanglement by combining dichotomic measurements on a bidimensional system and phase-space inference through the Wigner distribution associated with the macroscopic component of the state. As a benchmark, we investigate the feasibility of our proposal in a bipartite-entangled state composed of a single-photon and a multiphoton field. Our analysis shows that, under ideal conditions, maximal violation of a Clauser-Horne-Shimony-Holt-based inequality is achievable regardless of the number of photons in the macroscopic part of the state. The difficulty in observing entanglement when losses and detection inefficiency are included can be overcome by using a hybrid entanglement witness that allows efficient correction for losses in the few-photon regime.

  11. Hybrid methods for witnessing entanglement in a microscopic-macroscopic system

    Energy Technology Data Exchange (ETDEWEB)

    Spagnolo, Nicolo [Dipartimento di Fisica, Sapienza Universita di Roma, Piazzale Aldo Moro 5, I-00185 Roma (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Piazzale Aldo Moro 5, I-00185 Roma (Italy); Vitelli, Chiara [Dipartimento di Fisica, Sapienza Universita di Roma, Piazzale Aldo Moro 5, I-00185 Roma (Italy); Paternostro, Mauro [School of Mathematics and Physics, Queen' s University, BT 7 1NN Belfast (United Kingdom); De Martini, Francesco [Dipartimento di Fisica, Sapienza Universita di Roma, Piazzale Aldo Moro 5, I-00185 Roma (Italy); Accademia Nazionale dei Lincei, via della Lungara 10, I-00165 Roma (Italy); Sciarrino, Fabio [Dipartimento di Fisica, Sapienza Universita di Roma, Piazzale Aldo Moro 5, I-00185 Roma (Italy); Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche (INO-CNR), largo E. Fermi 6, I-50125 Firenze (Italy)

    2011-09-15

    We propose a hybrid approach to the experimental assessment of the genuine quantum features of a general system consisting of microscopic and macroscopic parts. We infer entanglement by combining dichotomic measurements on a bidimensional system and phase-space inference through the Wigner distribution associated with the macroscopic component of the state. As a benchmark, we investigate the feasibility of our proposal in a bipartite-entangled state composed of a single-photon and a multiphoton field. Our analysis shows that, under ideal conditions, maximal violation of a Clauser-Horne-Shimony-Holt-based inequality is achievable regardless of the number of photons in the macroscopic part of the state. The difficulty in observing entanglement when losses and detection inefficiency are included can be overcome by using a hybrid entanglement witness that allows efficient correction for losses in the few-photon regime.

  12. A strict experimental test of macroscopic realism in a superconducting flux qubit.

    Science.gov (United States)

    Knee, George C; Kakuyanagi, Kosuke; Yeh, Mao-Chuang; Matsuzaki, Yuichiro; Toida, Hiraku; Yamaguchi, Hiroshi; Saito, Shiro; Leggett, Anthony J; Munro, William J

    2016-11-04

    Macroscopic realism is the name for a class of modifications to quantum theory that allow macroscopic objects to be described in a measurement-independent manner, while largely preserving a fully quantum mechanical description of the microscopic world. Objective collapse theories are examples which aim to solve the quantum measurement problem through modified dynamical laws. Whether such theories describe nature, however, is not known. Here we describe and implement an experimental protocol capable of constraining theories of this class, that is more noise tolerant and conceptually transparent than the original Leggett-Garg test. We implement the protocol in a superconducting flux qubit, and rule out (by ∼84 s.d.) those theories which would deny coherent superpositions of 170 nA currents over a ∼10 ns timescale. Further, we address the 'clumsiness loophole' by determining classical disturbance with control experiments. Our results constitute strong evidence for the superposition of states of nontrivial macroscopic distinctness.

  13. Macroscopic sessile tumor architecture is a pathologic feature of biologically aggressive upper tract urothelial carcinoma.

    Science.gov (United States)

    Fritsche, Hans-Martin; Novara, Giacomo; Burger, Maximilian; Gupta, Amit; Matsumoto, Kazumasa; Kassouf, Wassim; Sircar, Kanishka; Zattoni, Filiberto; Walton, Tom; Tritschler, Stefan; Baba, Shiro; Bastian, Patrick J; Martínez-Salamanca, Juan I; Seitz, Christian; Otto, Wolfgang; Wieland, Wolf Ferdinand; Karakiewicz, Pierre I; Ficarra, Vincenzo; Hartmann, Arndt; Shariat, Shahrokh F

    2012-09-01

    Macroscopic sessile tumor architecture was associated with adverse outcomes after radical nephroureterectomy (RNU) for upper tract urothelial carcinoma (UTUC). Before inclusion in daily clinical decision-making, the prognostic value of tumor architecture needs to be validated in an independent, external dataset. We tested whether macroscopic tumor architecture improves outcome prediction in an international cohort of patients. We retrospectively studied 754 patients treated with RNU for UTUC without neoadjuvant chemotherapy at 9 centers located in Asia, Canada, and Europe. Tumor architecture was macroscopically categorized as either papillary or sessile. Univariable and multivariable Cox regression analyses were used to address recurrence-free (RFS) and cancer-specific survival (CSS) estimates. Macroscopic sessile architecture was present in 20% of the patients. Its prevalence increased with advancing pathologic stage and it was significantly associated with established features of biologically aggressive UTUC, such as tumor grade, lymph node metastasis, lymphovascular invasion, and concomitant CIS (all P values architecture were 85% and 90%, compared with 58% and 66% for those with macroscopic sessile architecture, respectively (P values architecture was an independent predictor of both RFS (hazard ratio {HR}: 1.5; P = 0.036) and CSS (HR: 1.5; P = 0.03). We confirmed the independent prognostic value of macroscopic tumor architecture in a large, independent, multicenter UTUC cohort. It should be reported in every pathology report and included in post-RNU predictive models in order to refine current clinical decision making regarding follow-up protocol and adjuvant therapy. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Departure of microscopic friction from macroscopic drag in molecular fluid dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Hanasaki, Itsuo [Institute of Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588 (Japan); Fujiwara, Daiki; Kawano, Satoyuki, E-mail: kawano@me.es.osaka-u.ac.jp [Graduate School of Engineering Science, Osaka University, Machikaneyama-cho 1-3, Toyonaka, Osaka 560-8531 (Japan)

    2016-03-07

    Friction coefficient of the Langevin equation and drag of spherical macroscopic objects in steady flow at low Reynolds numbers are usually regarded as equivalent. We show that the microscopic friction can be different from the macroscopic drag when the mass is taken into account for particles with comparable scale to the surrounding fluid molecules. We illustrate it numerically by molecular dynamics simulation of chloride ion in water. Friction variation by the atomistic mass effect beyond the Langevin regime can be of use in the drag reduction technology as well as the electro or thermophoresis.

  15. Macroscopic behavior of fast reactor fuel subjected to simulated thermal transients

    International Nuclear Information System (INIS)

    Fenske, G.R.; Emerson, J.E.; Savoie, F.E.

    1983-06-01

    High-speed cinematography has been used to characterize the macroscopic behavior of irradiated and unirradiated fuel subjected to thermal transients prototypical of fast reactor transients. The results demonstrate that as the cladding melts, the fuel can disperse via spallation if the fuel contains in excess of approx. 16 μmoles/gm of fission gas. Once the cladding has melted, the macroscopic behavior (time to failure and dispersive nature) was strongly influenced by the presence of volatile fission products and the heating rate

  16. Generating macroscopic chaos in a network of globally coupled phase oscillators

    Science.gov (United States)

    So, Paul; Barreto, Ernest

    2011-01-01

    We consider an infinite network of globally coupled phase oscillators in which the natural frequencies of the oscillators are drawn from a symmetric bimodal distribution. We demonstrate that macroscopic chaos can occur in this system when the coupling strength varies periodically in time. We identify period-doubling cascades to chaos, attractor crises, and horseshoe dynamics for the macroscopic mean field. Based on recent work that clarified the bifurcation structure of the static bimodal Kuramoto system, we qualitatively describe the mechanism for the generation of such complicated behavior in the time varying case. PMID:21974662

  17. Serum Starvation-Induced Voltage-Gated Potassium Channel Kv7.5 Expression and Its Regulation by Sp1 in Canine Osteosarcoma Cells

    Directory of Open Access Journals (Sweden)

    Bo Hyung Lee

    2014-01-01

    Full Text Available The KCNQ gene family, whose members encode Kv7 channels, belongs to the voltage-gated potassium (Kv channel group. The roles of this gene family have been widely investigated in nerve and muscle cells. In the present study, we investigated several characteristics of Kv7.5, which is strongly expressed in the canine osteosarcoma cell line, CCL-183. Serum starvation upregulated Kv7.5 expression, and the Kv7 channel opener, flupirtine, attenuated cell proliferation by arresting cells in the G0/G1 phase. We also showed that Kv7.5 knockdown helps CCL-183 cells to proliferate. In an effort to find an endogenous regulator of Kv7.5, we used mithramycin A to reduce the level of the transcription factor Sp1, and it strongly inhibited the induction of Kv7.5 in CCL-183 cells. These results suggest that the activation of Kv7.5 by flupirtine may exert an anti-proliferative effect in canine osteosarcoma. Therefore, Kv7.5 is a possible molecular target for canine osteosarcoma therapy.

  18. Specific Kv1.3 blockade modulates key cholesterol-metabolism-associated molecules in human macrophages exposed to ox-LDL.

    Science.gov (United States)

    Yang, Yong; Wang, Yan-Fu; Yang, Xiao-Fang; Wang, Zhao-Hui; Lian, Yi-Tian; Yang, Ying; Li, Xiao-Wei; Gao, Xiang; Chen, Jian; Shu, Yan-Wen; Cheng, Long-Xian; Liao, Yu-Hua; Liu, Kun

    2013-01-01

    Cholesterol-metabolism-associated molecules, including scavenger receptor class A (SR-A), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), CD36, ACAT1, ABCA1, ABCG1, and scavenger receptor class B type I, can modulate cholesterol metabolism in the transformation from macrophages to foam cells. Voltage-gated potassium channel Kv1.3 has increasingly been demonstrated to play an important role in the modulation of macrophage function. Here, we investigate the role of Kv1.3 in modulating cholesterol-metabolism-associated molecules in human acute monocytic leukemia cell-derived macrophages (THP-1 macrophages) and human monocyte-derived macrophages exposed to oxidized LDL (ox-LDL). Human Kv1.3 and Kv1.5 channels (hKv1.3 and hKv1.5) are expressed in macrophages and form a heteromultimeric channel. The hKv1.3-E314 antibody that we had generated as a specific hKv1.3 blocker inhibited outward delayed rectifier potassium currents, whereas the hKv1.5-E313 antibody that we had generated as a specific hKv1.5 blocker failed. Accordingly, the hKv1.3-E314 antibody reduced percentage of cholesterol ester and enhanced apoA-I-mediated cholesterol efflux in THP-1 macrophages and human monocyte-derived macrophages exposed to ox-LDL. The hKv1.3-E314 antibody downregulated SR-A, LOX-1, and ACAT1 expression and upregulated ABCA1 expression in THP-1 macrophages and human monocyte-derived macrophages. Our results reveal that specific Kv1.3 blockade represents a novel strategy modulating cholesterol metabolism in macrophages, which benefits the treatment of atherosclerotic lesions.

  19. Specific Kv1.3 blockade modulates key cholesterol-metabolism-associated molecules in human macrophages exposed to ox-LDL[S

    Science.gov (United States)

    Yang, Yong; Wang, Yan-Fu; Yang, Xiao-Fang; Wang, Zhao-Hui; Lian, Yi-Tian; Yang, Ying; Li, Xiao-Wei; Gao, Xiang; Chen, Jian; Shu, Yan-Wen; Cheng, Long-Xian; Liao, Yu-Hua; Liu, Kun

    2013-01-01

    Cholesterol-metabolism-associated molecules, including scavenger receptor class A (SR-A), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), CD36, ACAT1, ABCA1, ABCG1, and scavenger receptor class B type I, can modulate cholesterol metabolism in the transformation from macrophages to foam cells. Voltage-gated potassium channel Kv1.3 has increasingly been demonstrated to play an important role in the modulation of macrophage function. Here, we investigate the role of Kv1.3 in modulating cholesterol-metabolism-associated molecules in human acute monocytic leukemia cell-derived macrophages (THP-1 macrophages) and human monocyte-derived macrophages exposed to oxidized LDL (ox-LDL). Human Kv1.3 and Kv1.5 channels (hKv1.3 and hKv1.5) are expressed in macrophages and form a heteromultimeric channel. The hKv1.3-E314 antibody that we had generated as a specific hKv1.3 blocker inhibited outward delayed rectifier potassium currents, whereas the hKv1.5-E313 antibody that we had generated as a specific hKv1.5 blocker failed. Accordingly, the hKv1.3-E314 antibody reduced percentage of cholesterol ester and enhanced apoA-I-mediated cholesterol efflux in THP-1 macrophages and human monocyte-derived macrophages exposed to ox-LDL. The hKv1.3-E314 antibody downregulated SR-A, LOX-1, and ACAT1 expression and upregulated ABCA1 expression in THP-1 macrophages and human monocyte-derived macrophages. Our results reveal that specific Kv1.3 blockade represents a novel strategy modulating cholesterol metabolism in macrophages, which benefits the treatment of atherosclerotic lesions. PMID:23099443

  20. Remodeling of Kv1.5 channel in right atria from Han Chinese patients with atrial fibrillation.

    Science.gov (United States)

    Ou, Xian-hong; Li, Miao-ling; Liu, Rui; Fan, Xin-rong; Mao, Liang; Fan, Xue-hui; Yang, Yan; Zeng, Xiao-rong

    2015-04-28

    The incidence of atrial fibrillation (AF) in rheumatic heart diseases (RHD) is very high and increases with age. Occurrence and maintenance of AF are very complicated process accompanied by many different mechanisms. Ion-channel remodeling, including the voltage-gated potassium channel Kv1.5, plays an important role in the pathophysiology of AF. However, the changes of Kv1.5 channel expression in Han Chinese patients with RHD and AF remain poorly understood. The aim of the present study was to investigate whether the Kv1.5 channels of the right atria may be altered with RHD, age, and sex to contribute to AF. Right atrial appendages were obtained from 20 patients with normal cardiac functions who had undergone surgery, and 26 patients with AF. Subjects were picked from 4 groups: adult and aged patients in normal sinus rhythm (SR) and AF. Patients were divided into non-RHD and RHD groups or men and women groups in normal SR and AF, respectively. The expression of Kv1.5 protein and messenger RNA (mRNA) were measured using Western blotting and polymerase chain reaction (PCR) method, respectively. Compared with the SR group, the expression of Kv1.5 protein decreased significantly in the AF group. However, neither Kv1.5 protein nor KCNA5 mRNA had significant differences in adult and aged groups, non-RHD and RHD group, and men and women group of AF. The expression of Kv1.5 channel protein changes with AF but not with age, RHD, and sex in AF.

  1. Dosimetry in phantom of newborn head for computerized tomography signs with voltages of 80, 100 and 120 KV

    International Nuclear Information System (INIS)

    Oliveira, G.A.P.; Mourão, A.P.

    2017-01-01

    Computed Tomography is the radiodiagnostic method that most contributes to the dose deposition in population. Therefore, the dose reductions used in these tests are very important, especially for pediatric patients who have a life expectancy greater than the rest of the population. This study purpose to compare the doses generated from newborns (NB) with different voltages in a 64-channel multichannel CT equipment of the GE brand. One head phantom in a cylindrical shape made in PMMA were used to newborn patient dimensions. 100 mA.s of charge of the X-ray tube were standardized, alternating the voltages between 80, 100, 120 kV in the axial acquisition. The absorbed dose measurements were performed with a pencil-type ionization chamber positioned within the five apertures in the phantom. The phantom was developed with the cephalic percentile of male NB of 14 and female of 28 days, respectively. The doses obtained in the head phantom of NB were compared with the voltages of 80, 100 and 120 kV. The volumetric dose index, C VOL , generated in the 120 kV protocol was 25.10 mGy, for 100 kV of 19,06 mGy and not for 80 kV 15,81 mGy. The results allow to evaluate that for the generation of images with 120 kV, the dose was 37.0% higher when compared to the voltage of 80 kV. The study shows that the increase in tension in the tomography protocols also makes it possible to increase the dose for the NB patient. (author)

  2. Dosimetry in phantom of newborn head for computerized tomography signs with voltages of 80, 100 and 120 KV

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, G.A.P.; Mourão, A.P., E-mail: giovanni.paiva@pbh.gov.br, E-mail: apratabhz@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear

    2017-07-01

    Computed Tomography is the radiodiagnostic method that most contributes to the dose deposition in population. Therefore, the dose reductions used in these tests are very important, especially for pediatric patients who have a life expectancy greater than the rest of the population. This study purpose to compare the doses generated from newborns (NB) with different voltages in a 64-channel multichannel CT equipment of the GE brand. One head phantom in a cylindrical shape made in PMMA were used to newborn patient dimensions. 100 mA.s of charge of the X-ray tube were standardized, alternating the voltages between 80, 100, 120 kV in the axial acquisition. The absorbed dose measurements were performed with a pencil-type ionization chamber positioned within the five apertures in the phantom. The phantom was developed with the cephalic percentile of male NB of 14 and female of 28 days, respectively. The doses obtained in the head phantom of NB were compared with the voltages of 80, 100 and 120 kV. The volumetric dose index, C{sub VOL}, generated in the 120 kV protocol was 25.10 mGy, for 100 kV of 19,06 mGy and not for 80 kV 15,81 mGy. The results allow to evaluate that for the generation of images with 120 kV, the dose was 37.0% higher when compared to the voltage of 80 kV. The study shows that the increase in tension in the tomography protocols also makes it possible to increase the dose for the NB patient. (author)

  3. SU-E-T-163: Thin-Film Organic Photocell (OPV) Properties in MV and KV Beams for Dosimetry Applications.

    Science.gov (United States)

    Ng, S K; Hesser, J; Zhang, H; Gowrisanker, S; Yakushevich, S; Shulhevich, Y; Abkai, C; Wack, L; Zygmanski, P

    2012-06-01

    To characterize dosimetric properties of low-cost thin film organic-based photovoltaic (OPV) cells to kV and MV x-ray beams for their usage as large area dosimeter for QA and patient safety monitoring device. A series of thin film OPV cells of various areas and thicknesses were irradiated with MV beams to evaluate the stability and reproducibility of their response, linearity and sensitivity to absorbed dose. The OPV response to x-rays of various linac energies were also characterized. Furthermore the practical (clinical) sensitivity of the cells was determined using IMRT sweeping gap test generated with various gap sizes. To evaluate their potential usage in the development of low cost kV imaging device, the OPV cells were irradiated with kV beam (60-120 kVp) from a fluoroscopy unit. Photocell response to the absorbed dose was characterized as a function of the organic thin film thickness and size, beam energy and exposure for kV beams as well. In addition, photocell response was determined with and without thin plastic scintillator. Response of the OPV cells to the absorbed dose from kV and MV beams are stable and reproducible. The photocell response was linearly proportional to the size and about slightly decreasing with the thickness of the organic thin film, which agrees with the general performance of the photocells in visible light. The photocell response increases as a linear function of absorbed dose and x-ray energy. The sweeping gap tests performed showed that OPV cells have sufficient practical sensitivity to measured MV x-ray delivery with gap size as small as 1 mm. With proper calibration, the OPV cells could be used for online radiation dose measurement for quality assurance and patient safety purposes. Their response to kV beam show promising potential in development of low cost kV radiation detection devices. © 2012 American Association of Physicists in Medicine.

  4. FPGA based control system for -100 kV, 25 A Crowbarless DC power supply

    International Nuclear Information System (INIS)

    Upadhyay, R.; Tripathi, A.; Badapanda, M.K.; Lad, M.

    2015-01-01

    FPGA based digital control system has been developed for -100 kV, 25 A solid state modular crowbarless DC klystron bias power supply of 1 MW, 352.2 MHz RF test stand. The control system has capability to operate this power supply either in CW or pulse mode. Central controller, PSM controller and graphical user interface are key parts of this control system. Central controller monitors the status of various subsystems of this power supply like 11 kV step start unit, four numbers of main transformers each having 44 numbers of secondary windings and 176 numbers of switch power modules for deciding the number of power modules to be put ON and their duty cycles depending on the set output voltage and current. PSM controller sends appropriate control signal to the switch power modules through fibre optic lines and communicates it to the central controller. Linux based graphical user interface has been developed which enables the user to set the operating parameters along with their trip limits and displays the information of critical parameters of this power supply on a local touch screen panel. Provision for remote control and supervision is also provided through a separate PC connected to the main control system via Ethernet. The control system has capability to trip the power supply within 5 μsec in case any parameter exceeds its set limit. Suitable data logging feature is incorporated for offline fault analysis. The control system architecture along with its software protection interlocks are presented in this paper. The performance of the control system has been verified during operation of -100 kV, 25 A DC power supply with 1 MW, 352.2 MHz klystron amplifier. (author)

  5. Development of 10 kV 4H-SiC JBS diode with FGR termination

    International Nuclear Information System (INIS)

    Huang Runhua; Tao Yonghong; Cao Pengfei; Wang Ling; Li Rui; Chen Gang; Bai Song; Li Yun; Zhao Zhifei

    2014-01-01

    The design, fabrication, and electrical characteristics of the 4H-SiC JBS diode with a breakdown voltage higher than 10 kV are presented. 60 floating guard rings have been used in the fabrication. Numerical simulations have been performed to select the doping level and thickness of the drift layer and the effectiveness of the edge termination technique. The n-type epilayer is 100 μm in thickness with a doping of 6 × 10 14 cm −3 . The on-state voltage was 2.7 V at J F = 13 A/cm 2 . (semiconductor devices)

  6. Back-to-Back Energization of a 60kV Cable Network - Inrush Currents Phenomenon

    DEFF Research Database (Denmark)

    Faria da Silva, Filipe; Bak, Claus Leth; Hansen, M. Lind

    2010-01-01

    On November 2008 the Danish government decided that all Danish transmission lines with a rated voltage equal to and below 150kV must be put underground, in order to reduce the visual pollution caused by Overhead Lines. This decision will lead to a massive use of underground cables in the Danish...... Network, and force a change in the approach used until now when planning, analyzing and operating electrical power systems. One problem that might arise is the energization of cables in parallel, as this operation may originate high inrush currents, which represent a risk to the circuit breakers connected...

  7. On low-resistance neutral earthing mode in 20 kV overhead and cable networks

    Directory of Open Access Journals (Sweden)

    Mayorov Andrey

    2017-01-01

    Full Text Available The problems of justification and selection of the required single-phase short-circuit current values in cable and overhead networks of 20 kV with low-resistance neutral earthing are considered. It is shown that the desired values of the short-circuit current can be determined on the basis of harmonization of conflicting influencing factors: reliability of the relay protection and automation devices and required resistances of the earthing devices of electrical installations, including personnel safety. In this case, the main influencing factor is the electrical network structure and parameters

  8. Operating characteristics and modeling of the LLNL 100-kV electric gun

    International Nuclear Information System (INIS)

    Osher, J.E.; Barnes, G.; Chau, H.H.; Lee, R.S.; Lee, C.; Speer, R.; Weingart, R.C.

    1989-01-01

    In the electric gun, the explosion of an electrically heated metal foil and the accompanying magnetic forces drive a thin flyer plate up a short barrel. Flyer velocities of up to 18 km/s make the gun useful for hypervelocity impact studies. The authors briefly review the technological evolution of the exploding-metal circuit elements that power the gun, describe the 100-kV electric gun designed at Lawrence Livermore National Laboratory (LLNL) in some detail, and present the general principles of electric gun operation. They compare the experimental performance of the LLNL gun with a simple model and with predictions of a magnetohydrodynamics code

  9. Calculation of the electron trajectory for 200 kV self-shielded electron accelerator

    International Nuclear Information System (INIS)

    Wang Shuiqing

    2000-01-01

    In order to calculate the electron trajectory of 200 kV self-shielded electron accelerator, the electric field is calculated with a TRAJ program. In this program, following electron track mash points one by one, the electron beam trajectories are calculated. Knowing the effect of grid voltage on electron optics and gaining grid voltage focusing effect in the various energy grades, the authors have gained scientific basis for adjusting grid voltage, and also accumulated a wealth of experience for designing self-shielded electron accelerator or electron curtain in future

  10. PLTS Transformerless Tegangan 20 kV menggunakan Cascaded H-Bridge Multilevel Inverter

    Directory of Open Access Journals (Sweden)

    ANGGARA BRAJAMUSTHI

    2018-03-01

    Full Text Available ABSTRAK Aplikasi dari inverter multilevel pada sistem Pusat Listrik Tenaga Surya (PLTS dapat menghilangkan kebutuhan terhadap transformator, sehingga dapat mengurangi biaya investasi, mengurangi kompleksitas instalasi dan menghilangkan rugi-rugi daya transformator. Pada penelitian ini, sebuah inverter dengan topologi Cascaded H-Bridge Multilevel Inverter dirancang agar mampu mengubah tegangan rendah DC dari beberapa Photovoltaic (PV array menjadi tegangan fasa-fasa 20 kV AC. Perancangan menghasilkan sebuah inverter 3 fasa 27-level dimana setiap level masing-masing memiliki PV array, DC-DC boost converter, H-bridge inverter, dan keluaran 3 fasa terhubung dengan filter LCL. Setiap komponen dari inverter dan sistem tersebut kemudian dimodelkan pada MATLAB Simulink untuk mensimulasikan kinerja dari setiap komponen dan sistem pada Standard Test Condition (STC dari modul PV. Pada keadaan STC, daya 3 fasa maksimum yang dapat dihasilkan adalah 1,716 MW atau 68,54% dari daya DC maksimum sebesar 2,5 MWp. Sistem dapat menghasilkan tegangan fasa-fasa keluaran sebesar 20 kV dengan Total Harmonic Distortion (THD di bawah 5%. Kata kunci: Pusat Listrik Tenaga Surya (PLTS, photovoltaic, Cascaded H-Bridge Multilevel Inverter ABSTRACT The application of Multilevel Inverter in a Photovoltaic Solar Power Plant system could eliminate the needs of step-up transformer, which will reduce the system investment cost, simplify the system installation and also eliminate power losses of the transformer. In this paper, an inverter design was proposed with Cascaded H-Bridge Multilevel Inverter topology that is capable of converting low voltage DC power from several PV arrays into 20 kV AC power. The design resulted a 3 phase 27-level inverter where each level in the inverter has its own photovoltaic array, DC-DC boost converter, H-bridge inverter, and the 3 phase output is connected to LCL filter. Each component of the Inverter and the system were then modelled in MATLAB

  11. WE-G-18A-02: Calibration-Free Combined KV/MV Short Scan CBCT

    Energy Technology Data Exchange (ETDEWEB)

    Wu, M; Loo, B; Bazalova, M; Fahrig, R [Stanford University, Stanford, CA (United States); Star-Lack, J [Varian Medical Systems, Palo Alto, CA (United States)

    2014-06-15

    Purpose: To combine orthogonal kilo-voltage (kV) and Mega-voltage (MV) projection data for short scan cone-beam CT to reduce imaging time on current radiation treatment systems, using a calibration-free gain correction method. Methods: Combining two orthogonal projection data sets for kV and MV imaging hardware can reduce the scan angle to as small as 110° (90°+fan) such that the total scan time is ∼18 seconds, or within a breath hold. To obtain an accurate reconstruction, the MV projection data is first linearly corrected using linear regression using the redundant data from the start and end of the sinogram, and then the combined data is reconstructed using the FDK method. To correct for the different changes of attenuation coefficients in kV/MV between soft tissue and bone, the forward projection of the segmented bone and soft tissue from the first reconstruction in the redundant region are added to the linear regression model. The MV data is corrected again using the additional information from the segmented image, and combined with kV for a second FDK reconstruction. We simulated polychromatic 120 kVp (conventional a-Si EPID with CsI) and 2.5 MVp (prototype high-DQE MV detector) projection data with Poisson noise using the XCAT phantom. The gain correction and combined kV/MV short scan reconstructions were tested with head and thorax cases, and simple contrast-to-noise ratio measurements were made in a low-contrast pattern in the head. Results: The FDK reconstruction using the proposed gain correction method can effectively reduce artifacts caused by the differences of attenuation coefficients in the kV/MV data. The CNRs of the short scans for kV, MV, and kV/MV are 5.0, 2.6 and 3.4 respectively. The proposed gain correction method also works with truncated projections. Conclusion: A novel gain correction and reconstruction method was developed to generate short scan CBCT from orthogonal kV/MV projections. This work is supported by NIH Grant 5R01CA138426-05.

  12. SU-F-J-16: Planar KV Imaging Dose Reduction Study

    Energy Technology Data Exchange (ETDEWEB)

    Gershkevitsh, E; Zolotuhhin, D [North Estonia Medical Centre, Tallinn (Estonia)

    2016-06-15

    Purpose: IGRT has become an indispensable tool in modern radiotherapy with kV imaging used in many departments due to superior image quality and lower dose when compared to MV imaging. Many departments use manufacturer supplied protocols for imaging which are not always optimised between image quality and radiation dose (ALARA). Methods: Whole body phantom PBU-50 (Kyoto Kagaku ltd., Japan) for imaging in radiology has been imaged on Varian iX accelerator (Varian Medical Systems, USA) with OBI 1.5 system. Manufacturer’s default protocols were adapted by modifying kV and mAs values when imaging different anatomical regions of the phantom (head, thorax, abdomen, pelvis, extremities). Images with different settings were independently reviewed by two persons and their suitability for IGRT set-up correction protocols were evaluated. The suitable images with the lowest mAs were then selected. The entrance surface dose (ESD) for manufacturer’s default protocols and modified protocols were measured with RTI Black Piranha (RTI Group, Sweden) and compared. Image quality was also measured with kVQC phantom (Standard Imaging, USA) for different protocols. The modified protocols have been applied for clinical work. Results: For most cases optimized protocols reduced the ESD on average by a factor of 3(range 0.9–8.5). Further reduction in ESD has been observed by applying bow-tie filter designed for CBCT. The largest reduction in dose (12.2 times) was observed for Thorax lateral protocol. The dose was slightly increased (by 10%) for large pelvis AP protocol. Conclusion: Manufacturer’s default IGRT protocols could be optimised to reduce the ESD to the patient without losing the necessary image quality for patient set-up correction. For patient set-up with planar kV imaging the bony anatomy is mostly used and optimization should focus on this aspect. Therefore, the current approach with anthropomorphic phantom is more advantageous in optimization over standard kV quality

  13. A 350 KV nanosecond pulse voltage generator with adjustable pulsed-width

    International Nuclear Information System (INIS)

    Wang, X.; Wang, M.; Chen, Y.Q.; Zeng, L.G.; Han, M.

    2002-01-01

    This paper presents a 350 kV nanosecond pulse voltage generator (NPVG). The voltage pulsed-width can be adjusted from 30 to 160 ns. The generator consists of: Marx generator, pulsed forming line (PFL), main switch and matched impedance. The output voltage of Marx generator is over than nU c (n- the stage number of Marx generator, U c -the charging voltage of capacitor). When the pulse forming line is terminated with an impedance that is over than the characteristic impedance of PFL, the higher voltage pulse was provided for the load

  14. Scale model test on a novel 400 kV double-circuit composite pylon

    DEFF Research Database (Denmark)

    Wang, Qian; Bak, Claus Leth; Silva, Filipe Miguel Faria da

    This paper investigates lightning shielding performance of a novel 400 kV double-circuit composite pylon, with the method of scale model test. Lightning strikes to overhead lines were simulated by long-gap discharges between a high voltage electrode with an impulse voltage and equivalent conductors...... around the pylon is discussed. Combined test results and striking distance equation in electro-geometric model, the approximate maximum lightning current that can lead to shielding failure is calculated. Test results verify that the unusual negative shielding angle of - 60° in the composite pylon meets...... requirement and the shielding wires provide acceptable protection from lightning strikes....

  15. Development of a high current 250 kV photocathode dc gun

    International Nuclear Information System (INIS)

    Nishimori, Nobuyuki; Nagai, Ryoji; Sawamura, Masaru; Hajima, Ryoichi

    2016-01-01

    We have developed a high current photocathode dc gun at JAEA for the next generation light sources such as an energy recovery linac and high-repetition rate X-ray free electron laser. The gun is equipped with a multialkali photocathode preparation system. Quantum efficiency of 0.37% at 532 nm was obtained for a Cs_3Sb photocathode. The gun was high voltage conditioned up to 230 kV with a cathode electrode. Beam generation test from the multialkali photocathode will be performed by the end of FY2015. (author)

  16. Off-resonance transformer charging for 250-kV water Blumlein

    International Nuclear Information System (INIS)

    Cook, E.; Reginato, L.

    1978-01-01

    An off-resonance transformer for charging a 250-kV Blumlein system provides a viable alternative to other charging schemes by permitting the use of conventional thyratrons. Such a transformer must have reliability, a reasonable voltage step-up, and a non-reversing primary current. The analysis, design, and performance data for such a transformer are presented. The strong interrelationship between transformer design and Blumlein requirements necessitates that Blumlein description and design criterion be briefly presented prior to transformer design such that transformer load requirements be defined

  17. Pharmacological activation of Kv11.1 in transgenic long QT-1 rabbits

    DEFF Research Database (Denmark)

    Bentzen, Bo Hjorth; Bahrke, Sophia; Wu, Kezhong

    2011-01-01

    Transgenic rabbits expressing pore mutants of K(V)7.1 display a long QT syndrome 1 (LQT1) phenotype. Recently, NS1643 has been described to increase I(Kr).We hypothesized that NS1643 would shorten the action potential duration (APD(90)) in LQT1 rabbits. Transgenic LQT1 rabbits were compared...... with littermate control (LMC) rabbits. In vivo electrocardiogram studies in sedated animals were performed at baseline and during 45 minutes of intravenous infusion of NS1643 or vehicle in a crossover design. Ex vivo monophasic action potentials were recorded from Langendorff-perfused hearts at baseline...

  18. Sidney-North Yuma 230-kV Transmission Line Project, Colorado and Nebraska

    Energy Technology Data Exchange (ETDEWEB)

    1991-06-01

    This report describes the need for a 230-kV overhead transmission line to supply power from Sidney, Nebraska to eastern Colorado. The alternative scenario compared to construction of the line is No Action. Rejected alternatives include underground lines and different routing paths, with a possible extension to the Sterling area. Both scenarios are evaluated for environmental effects, cost, and consequences for the eastern Colorado region. The proposed route is determined to be the environmentally preferred choice. 120 refs., 6 figs., 13 tabs. (MHB)

  19. A 150 kV Isolation Transformer for a Neutron Generator

    International Nuclear Information System (INIS)

    Dechthummarong, C.; Pratumtip, P.; Thongleurm, C.; Vichaimongkol, P.; Charoennugul, R.; Vilaithong, T.

    1998-01-01

    The work aims at the design and construction of a 150 kV isolation transformer for a neutron generator. The transformer windings are designed to use cylindrical layers with circular enamel copper wires. The insulation of the dry type transformer uses the epoxy resin for encapsulated winding. This insulation is non-flammable under temperature 350 degree celsius and the breakdown voltage is 10-18 kV/mm. This insulation is suitable for insulating high voltage. The design of provides the temperature rise of winding not exceeding 65 degree celsius for protection of the cracking of epoxy resin due to the expansion of winding

  20. The influence of the 220 kv and 66 kv power electric systems and the subsystem of their servitude range in the 'chaco central' ecosystem in Paraguay; Relacion de tendido electrico de 220 kV y 66kV en el ecosistema del chaco central del Paraguay y el subsistema de su franja de servidumbre

    Energy Technology Data Exchange (ETDEWEB)

    Acosta E, Hugo Cesar [ANDE - Administracion Nacional de Electricidad, Assuncion (Paraguay)

    2001-07-01

    According to the report from DOP/EL, in a medium period of time it has been registered nine disconnections of the 66 kv power transmission line located in the Chaco zone occurred in the nocturnal period. Those disconnections affected negatively the milky processes of Colinas Menonitas, deteriorating more than 20,000 liters of milk for each cut of the electric energy service. DMA/IM has accomplished a investigation job together with DOM/FO and has found the main reasons for those disconnections, so based on them it has recommended possible solutions related to the problem.

  1. Outlook for use of 10 kV voltage in coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Voloshchenko, N.I.; Nabokov, E.P.; Razumnyy, Yu.T.

    1983-01-01

    Based on technical-economic studies of the models of the plans for electricity supply, the economic expediency is shown of comprehensive implementation of measures for transition of high-voltage equipment of the mines to voltage of 10 kV with simultaneous improvement in the permissible power of short circuiting to 150 MV X A. Technical problems were examined which are associated with creation of explosion-safe electrical equipment, corresponding to the new technical requirements for the system of electricity supply of the coal mine.

  2. Macroscopic treatment of radio emission from cosmic ray air showers based on shower simulations

    NARCIS (Netherlands)

    Werner, Klaus; Scholten, Olaf

    We present a macroscopic calculation of coherent electro-magnetic radiation from air showers initiated by ultra-high energy cosmic rays, based on currents obtained from Monte Carlo simulations of air showers in a realistic geo-magnetic field. We can clearly relate the time signal to the time

  3. Macroscopic Description of Pressure-anisotropy-driven Collective Instability in Intense Charged Particle Beams

    International Nuclear Information System (INIS)

    Strasburg, Sean; Davidson, Ronald C.

    2000-01-01

    The macroscopic warm-fluid model developed by Lund and Davidson [Phys.Plasmas 5, 3028 (1998)] is used in the smooth-focusing approximation to investigate detailed stability properties of an intense charged particle beam with pressure anisotropy, assuming small-amplitude electrostatic perturbations about a waterbag equilibrium

  4. Effect of the isovector coupling channel on the macroscopic part of ...

    Indian Academy of Sciences (India)

    Physics Department, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus, Syria. E-mail: pscientific@aec.org.sy. MS received 10 June 2012; revised 18 October 2012; accepted 12 December 2012. Abstract. The effect of isovector coupling channel on the macroscopic part of the nuclear binding energy is studied ...

  5. Energetic macroscopic representation and inversion-based control of a CVT-based HEV

    NARCIS (Netherlands)

    Chouhou, M.; Grée, F.; Jivan, C.; Bouscayrol, A.; Hofman, T.

    2014-01-01

    A Continuous Variable Transmission (CVT) is introduced in the simulation model of a Hybrid Electric Vehicle (HEV). The CVT-based vehicle simulation and its control are deduced from the Energetic Macroscopic Representation (EMR). Simulations are provided to show the interest of the CVT in term of

  6. Energetic macroscopic representation and inversion- based control of a CVT-based HEV

    NARCIS (Netherlands)

    Chouhou, M.; Grée, F.; Jivan, C.; Bouscayrol, A.; Hofman, T.

    2013-01-01

    A Continuous Variable Transmission (CVT) is introduced in the simulation model of a Hybrid Electric Vehicle (HEV). The CVT-based vehicle simulation and its control are deduced from the Energetic Macroscopic Representation (EMR). Simulations are provided to show the interest of the CVT in term of

  7. On the inclusion of macroscopic theory in Monte Carlo simulation using game theory

    International Nuclear Information System (INIS)

    Tatarkiewicz, J.

    1980-01-01

    This paper presents the inclusion of macroscopic damage theory into Monte Carlo particle-range simulation using game theory. A new computer code called RADDI was developed on the basis of this inclusion. Results of Monte Carlo damage simulation after 6.3 MeV proton bombardment of silicon are compared with experimental data of Bulgakov et al. (orig.)

  8. Study using macroscopic autoradiography of the distribution of vanadium 48 in the rat and mouse

    International Nuclear Information System (INIS)

    Serhrouchni, M.

    1982-07-01

    Study of vanadium 48 distribution in the laboratory animal by macroscopic autoradiography. Vanadium 48 bioavailability is zero after oral administration and good after pulmonary administration. It is distributed throughout the body with a particular affinity for bone and teeth. Study of perinatal metabolism [fr

  9. Macroscopic modeling for heat and water vapor transfer in dry snow by homogenization.

    Science.gov (United States)

    Calonne, Neige; Geindreau, Christian; Flin, Frédéric

    2014-11-26

    Dry snow metamorphism, involved in several topics related to cryospheric sciences, is mainly linked to heat and water vapor transfers through snow including sublimation and deposition at the ice-pore interface. In this paper, the macroscopic equivalent modeling of heat and water vapor transfers through a snow layer was derived from the physics at the pore scale using the homogenization of multiple scale expansions. The microscopic phenomena under consideration are heat conduction, vapor diffusion, sublimation, and deposition. The obtained macroscopic equivalent model is described by two coupled transient diffusion equations including a source term arising from phase change at the pore scale. By dimensional analysis, it was shown that the influence of such source terms on the overall transfers can generally not be neglected, except typically under small temperature gradients. The precision and the robustness of the proposed macroscopic modeling were illustrated through 2D numerical simulations. Finally, the effective vapor diffusion tensor arising in the macroscopic modeling was computed on 3D images of snow. The self-consistent formula offers a good estimate of the effective diffusion coefficient with respect to the snow density, within an average relative error of 10%. Our results confirm recent work that the effective vapor diffusion is not enhanced in snow.

  10. How can macroscopically normal peritoneum contribute to the pathogenesis of endometriosis?

    Science.gov (United States)

    Fassbender, Amelie; Overbergh, Lut; Verdrengh, Eefje; Kyama, Cleophas M; Vodolazakaia, Alexandra; Bokor, Attila; Meuleman, Christel; Peeraer, Karen; Tomassetti, Carla; Waelkens, Etienne; Mathieu, Chantal; D'Hooghe, Thomas

    2011-09-01

    This study indicates that the immunobiology of macroscopically normal peritoneum is relevant to understand the pathogenesis of endometriosis. Peritoneal interleukin 6, interleukin 12, and ferritin were differentially expressed in women with and without endometriosis. Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  11. Macroscopic quantum coherence in a magnetic nanoparticle above the surface of a superconductor

    Science.gov (United States)

    Chudnovsky; Friedman

    2000-12-11

    We study macroscopic quantum tunneling of the magnetic moment in a single-domain particle placed above the surface of a superconductor. Such a setup allows one to manipulate the height of the energy barrier, preserving the degeneracy of the ground state. The tunneling amplitude and the effect of the dissipation in the superconductor are computed.

  12. Macroscopic Quantum Coherence in a Magnetic Nanoparticle Above the Surface of a Superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Chudnovsky, Eugene M.; Friedman, Jonathan R.

    2000-12-11

    We study macroscopic quantum tunneling of the magnetic moment in a single-domain particle placed above the surface of a superconductor. Such a setup allows one to manipulate the height of the energy barrier, preserving the degeneracy of the ground state. The tunneling amplitude and the effect of the dissipation in the superconductor are computed.

  13. Macroscopic Quantum Coherence in a Magnetic Nanoparticle Above the Surface of a Superconductor

    International Nuclear Information System (INIS)

    Chudnovsky, Eugene M.; Friedman, Jonathan R.

    2000-01-01

    We study macroscopic quantum tunneling of the magnetic moment in a single-domain particle placed above the surface of a superconductor. Such a setup allows one to manipulate the height of the energy barrier, preserving the degeneracy of the ground state. The tunneling amplitude and the effect of the dissipation in the superconductor are computed

  14. Experimental determination of neutron lifetimes through macroscopic neutron noise in the IPEN/MB-01 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Gonnelli, Eduardo; Diniz, Ricardo [Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP Travessa R-400, 05508-900, Cidade Universitaria, Sao Paulo (Brazil)

    2013-05-06

    The neutron lifetimes of the core, reflector, and global were experimentally obtained through macroscopic neutron noise in the IPEN/MB-01 reactor for five levels of subcriticality. The theoretical Auto Power Spectral Densities were derived by point kinetic equations taking the reflector effect into account, and one of the approaches consider an additional group of delayed neutrons.

  15. Bilateral subacromial bursitis with macroscopic rice bodies: Ultrasound, CT and MR appearance

    International Nuclear Information System (INIS)

    Law, T.C.; Chong, S.F.; Lu, P.P.; Mak, K.H.

    1998-01-01

    The radiological findings of ultrasound, CT and MR of a case of bilateral subacromial bursitis with macroscopic rice bodies is described. MRI is the investigation of choice and the intravenous gadolinium-enhanced usefulness was noted. The previous literature is also reviewed. Copyright (1998) Blackwell Science Pty Ltd

  16. Bilateral subacromial bursitis with macroscopic rice bodies: Ultrasound, CT and MR appearance

    Energy Technology Data Exchange (ETDEWEB)

    Law, T.C.; Chong, S.F.; Lu, P.P. [Kwong Wah Hospital (Hong Kong). Department of Radiology; Mak, K.H. [Kwong Wah Hospital (Hong Kong). Department of Orthopaedics and Traumatology

    1998-05-01

    The radiological findings of ultrasound, CT and MR of a case of bilateral subacromial bursitis with macroscopic rice bodies is described. MRI is the investigation of choice and the intravenous gadolinium-enhanced usefulness was noted. The previous literature is also reviewed. Copyright (1998) Blackwell Science Pty Ltd 5 refs., 1 tab., 4 figs.

  17. Collective motion of macroscopic spheres floating on capillary ripples: Dynamic heterogeneity and dynamic criticality

    NARCIS (Netherlands)

    Sanli, Ceyda; Saitoh, K.; Luding, Stefan; van der Meer, Roger M.

    2014-01-01

    When a densely packed monolayer of macroscopic spheres floats on chaotic capillary Faraday waves, a coexistence of large scale convective motion and caging dynamics typical for glassy systems is observed. We subtract the convective mean flow using a coarse graining (homogenization) method and reveal

  18. Self-similar drag reduction in plug-flow of suspensions of macroscopic fibers

    NARCIS (Netherlands)

    Gillissen, J.J.J.; Hoving, J.P.

    2012-01-01

    Pipe flow experiments show that turbulent drag reduction in plug-flow of concentrated suspensions of macroscopic fibers is a self-similar function of the wall shear stress over the fiber network yield stress. We model the experimental observations, by assuming a central fiber network plug, whose

  19. Analysis of macroscopic and microscopic rotating motions in rotating jets: A direct numerical simulation

    Directory of Open Access Journals (Sweden)

    Xingtuan Yang

    2015-05-01

    Full Text Available A direct numerical simulation study of the characteristics of macroscopic and microscopic rotating motions in swirling jets confined in a rectangular flow domain is carried out. The different structures of vortex cores for different swirl levels are illustrated. It is found that the vortex cores of low swirl flows are of regular cylindrical-helix patterns, whereas those of the high swirl flows are characterized by the formation of the bubble-type vortex breakdown followed by the radiant processing vortex cores. The results of mean velocity fields show the general procedures of vortex origination. Moreover, the effects of macroscopic and microscopic rotating motions with respect to the mean and fluctuation fields of the swirling flows are evaluated. The microscopic rotating effects, especially the effects with respect to the turbulent fluctuation motion, are increasingly intermittent with the increase in the swirl levels. In contrast, the maximum value of the probability density functions with respect to the macroscopic rotating effects of the fluctuation motion occurs at moderate swirl levels since the macroscopic rotating effects are attenuated by the formation of the bubble vortex breakdown with a region of stagnant fluids at supercritical swirl levels.

  20. Are the toroidal shapes of heavy-ion reactions seen in macroscopic drop collisions?

    International Nuclear Information System (INIS)

    Menchaca R, A.; Borunda, M.; Hidalgo, S.S.; Huidobro, F.; Michaelian, K.; Perez, A.; Rodriguez, V.

    1996-01-01

    Experiments involving the collisions of water, and mineral oil, drops are reported. The aim is to search for toroidal configurations predicted by, both, macroscopic fluid dynamic and nuclear models. Instead, we find the formation of thin liquid sheets surrounded by a somewhat thicker rim presenting a fingering instability. (Author)

  1. On the origin and elimination of macroscopic defects in MBE films

    Science.gov (United States)

    Wood, C. E. C.; Rathbun, L.; Ohno, H.; DeSimone, D.

    1981-02-01

    Spitting of group III metal droplets from Knudsen type effusion cells has been found culpable for a genre of problematical macroscopic surface topographical defects observed in the growth of semiconductor films by molecular beam epitaxy. Successful precautions are described which virtually eliminate the problem.

  2. Lability of Nanoparticulate Metal Complexes at a Macroscopic Metal Responsive (Bio)interface

    NARCIS (Netherlands)

    Duval, Jérôme F.L.; Town, Raewyn M.; Leeuwen, Van Herman P.

    2018-01-01

    The lability of metal complexes expresses the extent of the dissociative contribution of the complex species to the flux of metal ions toward a macroscopic metal-responsive (bio)interface, for example, an electrodic sensor or an organism. While the case of molecular ligands is well-established, it

  3. Pinning of a curved flux line by macroscopic inclusions in a type II superconductor

    International Nuclear Information System (INIS)

    Shehata, L.N.; Saif, A.G.

    1983-08-01

    The pinning force is calculated as a function of the distance between a curved (or straight) flux line and the centre of a macroscopic superconducting (or normal) ellipsoidal inclusion. When the ellipsoidal tends to a spherical inclusion the results agree with those previously obtained. (author)

  4. Pollen and macroscopic analyses of sediments from two lakes in the High Tatra mountains, Slovakia

    Czech Academy of Sciences Publication Activity Database

    Rybníčková, Eliška; Rybníček, Kamil

    2006-01-01

    Roč. 15, - (2006), s. 345-356 ISSN 0939-6314 R&D Projects: GA ČR(CZ) GA206/96/0531; GA ČR GA206/02/0568 Institutional research plan: CEZ:AV0Z60050516 Keywords : Pollen analyses * macroscopic analyses * high mointain lakes Subject RIV: EF - Botanics Impact factor: 0.649, year: 2006

  5. Macroscopic networks in the human brain: mapping connectivity in healthy and damaged brains

    NARCIS (Netherlands)

    Nijhuis, E.H.J.

    2013-01-01

    The human brain contains a network of interconnected neurons. Recent advances in functional and structural in-vivo magnetic resonance neuroimaging (MRI) techniques have provided opportunities to model the networks of the human brain on a macroscopic scale. This dissertation investigates the

  6. Testing quantum mechanics against macroscopic realism using the output of χ(2) nonlinearity

    International Nuclear Information System (INIS)

    Podoshvedov, Sergey A.; Kim, Jaewan

    2006-01-01

    We suggest an all-optical scheme to generate entangled superposition of a single photon with macroscopic entangled states for testing macroscopic realism. The scheme consists of source of single photons, a Mach-Zehnder interferometer in routes of which a system of coupled-down converters with type-I phase matching is inserted, and a beam splitter for the other auxiliary modes of the scheme. We use quantization of the pumping modes, depletion of the coherent states passing through the system, and interference effect in the pumping modes in the process of erasing which-path information of the single-photon on exit from the Mach-Zehnder interferometer. We show the macroscopic fields of the output superposition are distinguishable states. This scheme generates macroscopic entangled state that violates Bell's inequality. Moreover, the detailed analysis concerning change of amplitudes of entangled superposition by means of repeating this process many times is accomplished. We show our scheme works without photon number resolving detection and it is robust to detector inefficiency

  7. General multi-group macroscopic modeling for thermo-chemical non-equilibrium gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yen, E-mail: yen.liu@nasa.gov; Vinokur, Marcel [NASA Ames Research Center, Moffett Field, California 94035 (United States); Panesi, Marco; Sahai, Amal [University of Illinois, Urbana-Champaign, Illinois 61801 (United States)

    2015-04-07

    This paper opens a new door to macroscopic modeling for thermal and chemical non-equilibrium. In a game-changing approach, we discard conventional theories and practices stemming from the separation of internal energy modes and the Landau-Teller relaxation equation. Instead, we solve the fundamental microscopic equations in their moment forms but seek only optimum representations for the microscopic state distribution function that provides converged and time accurate solutions for certain macroscopic quantities at all times. The modeling makes no ad hoc assumptions or simplifications at the microscopic level and includes all possible collisional and radiative processes; it therefore retains all non-equilibrium fluid physics. We formulate the thermal and chemical non-equilibrium macroscopic equations and rate coefficients in a coupled and unified fashion for gases undergoing completely general transitions. All collisional partners can have internal structures and can change their internal energy states after transitions. The model is based on the reconstruction of the state distribution function. The internal energy space is subdivided into multiple groups in order to better describe non-equilibrium state distributions. The logarithm of the distribution function in each group is expressed as a power series in internal energy based on the maximum entropy principle. The method of weighted residuals is applied to the microscopic equations to obtain macroscopic moment equations and rate coefficients succinctly to any order. The model’s accuracy depends only on the assumed expression of the state distribution function and the number of groups used and can be self-checked for accuracy and convergence. We show that the macroscopic internal energy transfer, similar to mass and momentum transfers, occurs through nonlinear collisional processes and is not a simple relaxation process described by, e.g., the Landau-Teller equation. Unlike the classical vibrational energy

  8. General multi-group macroscopic modeling for thermo-chemical non-equilibrium gas mixtures

    Science.gov (United States)

    Liu, Yen; Panesi, Marco; Sahai, Amal; Vinokur, Marcel

    2015-04-01

    This paper opens a new door to macroscopic modeling for thermal and chemical non-equilibrium. In a game-changing approach, we discard conventional theories and practices stemming from the separation of internal energy modes and the Landau-Teller relaxation equation. Instead, we solve the fundamental microscopic equations in their moment forms but seek only optimum representations for the microscopic state distribution function that provides converged and time accurate solutions for certain macroscopic quantities at all times. The modeling makes no ad hoc assumptions or simplifications at the microscopic level and includes all possible collisional and radiative processes; it therefore retains all non-equilibrium fluid physics. We formulate the thermal and chemical non-equilibrium macroscopic equations and rate coefficients in a coupled and unified fashion for gases undergoing completely general transitions. All collisional partners can have internal structures and can change their internal energy states after transitions. The model is based on the reconstruction of the state distribution function. The internal energy space is subdivided into multiple groups in order to better describe non-equilibrium state distributions. The logarithm of the distribution function in each group is expressed as a power series in internal energy based on the maximum entropy principle. The method of weighted residuals is applied to the microscopic equations to obtain macroscopic moment equations and rate coefficients succinctly to any order. The model's accuracy depends only on the assumed expression of the state distribution function and the number of groups used and can be self-checked for accuracy and convergence. We show that the macroscopic internal energy transfer, similar to mass and momentum transfers, occurs through nonlinear collisional processes and is not a simple relaxation process described by, e.g., the Landau-Teller equation. Unlike the classical vibrational energy

  9. General multi-group macroscopic modeling for thermo-chemical non-equilibrium gas mixtures.

    Science.gov (United States)

    Liu, Yen; Panesi, Marco; Sahai, Amal; Vinokur, Marcel

    2015-04-07

    This paper opens a new door to macroscopic modeling for thermal and chemical non-equilibrium. In a game-changing approach, we discard conventional theories and practices stemming from the separation of internal energy modes and the Landau-Teller relaxation equation. Instead, we solve the fundamental microscopic equations in their moment forms but seek only optimum representations for the microscopic state distribution function that provides converged and time accurate solutions for certain macroscopic quantities at all times. The modeling makes no ad hoc assumptions or simplifications at the microscopic level and includes all possible collisional and radiative processes; it therefore retains all non-equilibrium fluid physics. We formulate the thermal and chemical non-equilibrium macroscopic equations and rate coefficients in a coupled and unified fashion for gases undergoing completely general transitions. All collisional partners can have internal structures and can change their internal energy states after transitions. The model is based on the reconstruction of the state distribution function. The internal energy space is subdivided into multiple groups in order to better describe non-equilibrium state distributions. The logarithm of the distribution function in each group is expressed as a power series in internal energy based on the maximum entropy principle. The method of weighted residuals is applied to the microscopic equations to obtain macroscopic moment equations and rate coefficients succinctly to any order. The model's accuracy depends only on the assumed expression of the state distribution function and the number of groups used and can be self-checked for accuracy and convergence. We show that the macroscopic internal energy transfer, similar to mass and momentum transfers, occurs through nonlinear collisional processes and is not a simple relaxation process described by, e.g., the Landau-Teller equation. Unlike the classical vibrational energy

  10. General multi-group macroscopic modeling for thermo-chemical non-equilibrium gas mixtures

    International Nuclear Information System (INIS)

    Liu, Yen; Vinokur, Marcel; Panesi, Marco; Sahai, Amal

    2015-01-01

    This paper opens a new door to macroscopic modeling for thermal and chemical non-equilibrium. In a game-changing approach, we discard conventional theories and practices stemming from the separation of internal energy modes and the Landau-Teller relaxation equation. Instead, we solve the fundamental microscopic equations in their moment forms but seek only optimum representations for the microscopic state distribution function that provides converged and time accurate solutions for certain macroscopic quantities at all times. The modeling makes no ad hoc assumptions or simplifications at the microscopic level and includes all possible collisional and radiative processes; it therefore retains all non-equilibrium fluid physics. We formulate the thermal and chemical non-equilibrium macroscopic equations and rate coefficients in a coupled and unified fashion for gases undergoing completely general transitions. All collisional partners can have internal structures and can change their internal energy states after transitions. The model is based on the reconstruction of the state distribution function. The internal energy space is subdivided into multiple groups in order to better describe non-equilibrium state distributions. The logarithm of the distribution function in each group is expressed as a power series in internal energy based on the maximum entropy principle. The method of weighted residuals is applied to the microscopic equations to obtain macroscopic moment equations and rate coefficients succinctly to any order. The model’s accuracy depends only on the assumed expression of the state distribution function and the number of groups used and can be self-checked for accuracy and convergence. We show that the macroscopic internal energy transfer, similar to mass and momentum transfers, occurs through nonlinear collisional processes and is not a simple relaxation process described by, e.g., the Landau-Teller equation. Unlike the classical vibrational energy

  11. β-Secretase BACE1 Promotes Surface Expression and Function of Kv3.4 at Hippocampal Mossy Fiber Synapses.

    Science.gov (United States)

    Hartmann, Stephanie; Zheng, Fang; Kyncl, Michele C; Karch, Sandra; Voelkl, Kerstin; Zott, Benedikt; D'Avanzo, Carla; Lomoio, Selene; Tesco, Giuseppina; Kim, Doo Y; Alzheimer, Christian; Huth, Tobias

    2018-04-04

    The β-secretase β-site APP-cleaving enzyme 1 (BACE1) is deemed a major culprit in Alzheimer's disease, but accumulating evidence indicates that there is more to the enzyme than driving the amyloidogenic processing of the amyloid precursor protein. For example, BACE1 has emerged as an important regulator of neuronal activity through proteolytic and, most unexpectedly, also through nonproteolytic interactions with several ion channels. Here, we identify and characterize the voltage-gated K + channel 3.4 (Kv3.4) as a new and functionally relevant interaction partner of BACE1. Kv3.4 gives rise to A-type current with fast activating and inactivating kinetics and serves to repolarize the presynaptic action potential. We found that BACE1 and Kv3.4 are highly enriched and remarkably colocalized in hippocampal mossy fibers (MFs). In BACE1 -/- mice of either sex, Kv3.4 surface expression was significantly reduced in the hippocampus and, in synaptic fractions thereof, Kv3.4 was specifically diminished, whereas protein levels of other presynaptic K + channels such as K Ca 1.1 and K Ca 2.3 remained unchanged. The apparent loss of presynaptic Kv3.4 affected the strength of excitatory transmission at the MF-CA3 synapse in hippocampal slices of BACE1 -/- mice when probed with the Kv3 channel blocker BDS-I. The effect of BACE1 on Kv3.4 expression and function should be bidirectional, as predicted from a heterologous expression system, in which BACE1 cotransfection produced a concomitant upregulation of Kv3.4 surface level and current based on a physical interaction between the two proteins. Our data show that, by targeting Kv3.4 to presynaptic sites, BACE1 endows the terminal with a powerful means to regulate the strength of transmitter release. SIGNIFICANCE STATEMENT The β-secretase β-site APP-cleaving enzyme 1 (BACE1) is infamous for its crucial role in the pathogenesis of Alzheimer's disease, but its physiological functions in the intact nervous system are only gradually

  12. Metal artifact correction for x-ray computed tomography using kV and selective MV imaging

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Meng, E-mail: mengwu@stanford.edu [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Keil, Andreas [microDimensions GmbH, Munich 81379 (Germany); Constantin, Dragos; Star-Lack, Josh [Varian Medical Systems, Inc., Palo Alto, California 94304 (United States); Zhu, Lei [Nuclear and Radiological Engineering and Medical Physics Programs, The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States)

    2014-12-15

    Purpose: The overall goal of this work is to improve the computed tomography (CT) image quality for patients with metal implants or fillings by completing the missing kilovoltage (kV) projection data with selectively acquired megavoltage (MV) data that do not suffer from photon starvation. When both of these imaging systems, which are available on current radiotherapy devices, are used, metal streak artifacts are avoided, and the soft-tissue contrast is restored, even for regions in which the kV data cannot contribute any information. Methods: Three image-reconstruction methods, including two filtered back-projection (FBP)-based analytic methods and one iterative method, for combining kV and MV projection data from the two on-board imaging systems of a radiotherapy device are presented in this work. The analytic reconstruction methods modify the MV data based on the information in the projection or image domains and then patch the data onto the kV projections for a FBP reconstruction. In the iterative reconstruction, the authors used dual-energy (DE) penalized weighted least-squares (PWLS) methods to simultaneously combine the kV/MV data and perform the reconstruction. Results: The authors compared kV/MV reconstructions to kV-only reconstructions using a dental phantom with fillings and a hip-implant numerical phantom. Simulation results indicated that dual-energy sinogram patch FBP and the modified dual-energy PWLS method can successfully suppress metal streak artifacts and restore information lost due to photon starvation in the kV projections. The root-mean-square errors of soft-tissue patterns obtained using combined kV/MV data are 10–15 Hounsfield units smaller than those of the kV-only images, and the structural similarity index measure also indicates a 5%–10% improvement in the image quality. The added dose from the MV scan is much less than the dose from the kV scan if a high efficiency MV detector is assumed. Conclusions: The authors have shown that it

  13. Metal artifact correction for x-ray computed tomography using kV and selective MV imaging

    International Nuclear Information System (INIS)

    Wu, Meng; Keil, Andreas; Constantin, Dragos; Star-Lack, Josh; Zhu, Lei; Fahrig, Rebecca

    2014-01-01

    Purpose: The overall goal of this work is to improve the computed tomography (CT) image quality for patients with metal implants or fillings by completing the missing kilovoltage (kV) projection data with selectively acquired megavoltage (MV) data that do not suffer from photon starvation. When both of these imaging systems, which are available on current radiotherapy devices, are used, metal streak artifacts are avoided, and the soft-tissue contrast is restored, even for regions in which the kV data cannot contribute any information. Methods: Three image-reconstruction methods, including two filtered back-projection (FBP)-based analytic methods and one iterative method, for combining kV and MV projection data from the two on-board imaging systems of a radiotherapy device are presented in this work. The analytic reconstruction methods modify the MV data based on the information in the projection or image domains and then patch the data onto the kV projections for a FBP reconstruction. In the iterative reconstruction, the authors used dual-energy (DE) penalized weighted least-squares (PWLS) methods to simultaneously combine the kV/MV data and perform the reconstruction. Results: The authors compared kV/MV reconstructions to kV-only reconstructions using a dental phantom with fillings and a hip-implant numerical phantom. Simulation results indicated that dual-energy sinogram patch FBP and the modified dual-energy PWLS method can successfully suppress metal streak artifacts and restore information lost due to photon starvation in the kV projections. The root-mean-square errors of soft-tissue patterns obtained using combined kV/MV data are 10–15 Hounsfield units smaller than those of the kV-only images, and the structural similarity index measure also indicates a 5%–10% improvement in the image quality. The added dose from the MV scan is much less than the dose from the kV scan if a high efficiency MV detector is assumed. Conclusions: The authors have shown that it

  14. Metal artifact correction for x-ray computed tomography using kV and selective MV imaging.

    Science.gov (United States)

    Wu, Meng; Keil, Andreas; Constantin, Dragos; Star-Lack, Josh; Zhu, Lei; Fahrig, Rebecca

    2014-12-01

    The overall goal of this work is to improve the computed tomography (CT) image quality for patients with metal implants or fillings by completing the missing kilovoltage (kV) projection data with selectively acquired megavoltage (MV) data that do not suffer from photon starvation. When both of these imaging systems, which are available on current radiotherapy devices, are used, metal streak artifacts are avoided, and the soft-tissue contrast is restored, even for regions in which the kV data cannot contribute any information. Three image-reconstruction methods, including two filtered back-projection (FBP)-based analytic methods and one iterative method, for combining kV and MV projection data from the two on-board imaging systems of a radiotherapy device are presented in this work. The analytic reconstruction methods modify the MV data based on the information in the projection or image domains and then patch the data onto the kV projections for a FBP reconstruction. In the iterative reconstruction, the authors used dual-energy (DE) penalized weighted least-squares (PWLS) methods to simultaneously combine the kV/MV data and perform the reconstruction. The authors compared kV/MV reconstructions to kV-only reconstructions using a dental phantom with fillings and a hip-implant numerical phantom. Simulation results indicated that dual-energy sinogram patch FBP and the modified dual-energy PWLS method can successfully suppress metal streak artifacts and restore information lost due to photon starvation in the kV projections. The root-mean-square errors of soft-tissue patterns obtained using combined kV/MV data are 10-15 Hounsfield units smaller than those of the kV-only images, and the structural similarity index measure also indicates a 5%-10% improvement in the image quality. The added dose from the MV scan is much less than the dose from the kV scan if a high efficiency MV detector is assumed. The authors have shown that it is possible to improve the image quality of

  15. Kv1.1 knock-in ataxic mice exhibit spontaneous myokymic activity exacerbated by fatigue, ischemia and low temperature.

    Science.gov (United States)

    Brunetti, Orazio; Imbrici, Paola; Botti, Fabio Massimo; Pettorossi, Vito Enrico; D'Adamo, Maria Cristina; Valentino, Mario; Zammit, Christian; Mora, Marina; Gibertini, Sara; Di Giovanni, Giuseppe; Muscat, Richard; Pessia, Mauro

    2012-09-01

    Episodic ataxia type 1 (EA1) is an autosomal dominant neurological disorder characterized by myokymia and attacks of ataxic gait often precipitated by stress. Several genetic mutations have been identified in the Shaker-like K(+) channel Kv1.1 (KCNA1) of EA1 individuals, including V408A, which result in remarkable channel dysfunction. By inserting the heterozygous V408A, mutation in one Kv1.1 allele, a mouse model of EA1 has been generated (Kv1.1(V408A/+)). Here, we investigated the neuromuscular transmission of Kv1.1(V408A/+) ataxic mice and their susceptibility to physiologically relevant stressors. By using in vivo preparations of lateral gastrocnemius (LG) nerve-muscle from Kv1.1(+/+) and Kv1.1(V408A/+) mice, we show that the mutant animals exhibit spontaneous myokymic discharges consisting of repeated singlets, duplets or multiplets, despite motor nerve axotomy. Two-photon laser scanning microscopy from the motor nerve, ex vivo, revealed spontaneous Ca(2+) signals that occurred abnormally only in preparations dissected from Kv1.1(V408A/+) mice. Spontaneous bursting activity, as well as that evoked by sciatic nerve stimulation, was exacerbated by muscle fatigue, ischemia and low temperatures. These stressors also increased the amplitude of compound muscle action potential. Such abnormal neuromuscular transmission did not alter fiber type composition, neuromuscular junction and vascularization of LG muscle, analyzed by light and electron microscopy. Taken together these findings provide direct evidence that identifies the motor nerve as an important generator of myokymic activity, that dysfunction of Kv1.1 channels alters Ca(2+) homeostasis in motor axons, and also strongly suggest that muscle fatigue contributes more than PNS fatigue to exacerbate the myokymia/neuromyotonia phenotype. More broadly, this study points out that juxtaparanodal K(+) channels composed of Kv1.1 subunits exert an important role in dampening the excitability of motor nerve axons during

  16. Macroscopic Hematuria After Conventional or Hypofractionated Radiation Therapy: Results From a Prospective Phase 3 Study

    Energy Technology Data Exchange (ETDEWEB)

    Sanguineti, Giuseppe, E-mail: sanguineti@ifo.it [Department of Radiation Oncology, Regina Elena National Cancer Institute, Rome (Italy); Arcidiacono, Fabio [Department of Radiation Oncology, Regina Elena National Cancer Institute, Rome (Italy); Landoni, Valeria [Department of Physics, Regina Elena National Cancer Institute, Rome (Italy); Saracino, Bianca Maria; Farneti, Alessia; Arcangeli, Stefano; Petrongari, Maria Grazia; Gomellini, Sara [Department of Radiation Oncology, Regina Elena National Cancer Institute, Rome (Italy); Strigari, Lidia [Department of Physics, Regina Elena National Cancer Institute, Rome (Italy); Arcangeli, Giorgio [Department of Radiation Oncology, Regina Elena National Cancer Institute, Rome (Italy)

    2016-10-01

    Purpose: To assess the macroscopic hematuria rates within a single-institution randomized phase 3 trial comparing dose-escalated, conventionally fractionated radiation therapy (CFRT) and moderately hypofractionated radiation therapy (MHRT) for localized prostate cancer. Methods and Materials: Patients with intermediate- to high-risk localized prostate cancer were treated with conformal RT and short-course androgen deprivation. Both the prostate and the entire seminal vesicles were treated to 80 Gy in 40 fractions over 8 weeks (CFRT) or 62 Gy in 20 fractions over 5 weeks (MHRT). The endpoint of the present study was the development of any episode or grade of macroscopic hematuria. The median follow-up period was 93 months (range 6-143). Results: Macroscopic hematuria was reported by 25 of 168 patients (14.9%). The actuarial estimate of hematuria at 8 years was 17.0% (95% confidence interval [CI] 10.7%-23.3%). The number of patients with hematuria was 6 and 19 in the CFRT and MHRT arms, respectively, for an actuarial 8-year estimate of 9.7% and 24.3%, respectively (hazard ratio 3.468, 95% CI 1.385-8.684; P=.008). Overall, 8 of 25 patients were found to have biopsy-proven urothelial carcinoma (3 in the CFRT arm and 5 in the MHRT arm; P=.27). Thus, the 8-year actuarial incidence of macroscopic hematuria (after censoring urothelial cancer–related episodes) was 4.1% and 18.2% after CFRT and MHRT, respectively (hazard ratio 4.961, 95% CI 1.426-17.263; P=.012). The results were confirmed by multivariate analysis after accounting for several patient-, treatment-, and tumor-related covariates. Conclusions: MHRT was associated with a statistically significant increased risk of macroscopic hematuria compared with CFRT.

  17. Macroscopic Hematuria After Conventional or Hypofractionated Radiation Therapy: Results From a Prospective Phase 3 Study

    International Nuclear Information System (INIS)

    Sanguineti, Giuseppe; Arcidiacono, Fabio; Landoni, Valeria; Saracino, Bianca Maria; Farneti, Alessia; Arcangeli, Stefano; Petrongari, Maria Grazia; Gomellini, Sara; Strigari, Lidia; Arcangeli, Giorgio

    2016-01-01

    Purpose: To assess the macroscopic hematuria rates within a single-institution randomized phase 3 trial comparing dose-escalated, conventionally fractionated radiation therapy (CFRT) and moderately hypofractionated radiation therapy (MHRT) for localized prostate cancer. Methods and Materials: Patients with intermediate- to high-risk localized prostate cancer were treated with conformal RT and short-course androgen deprivation. Both the prostate and the entire seminal vesicles were treated to 80 Gy in 40 fractions over 8 weeks (CFRT) or 62 Gy in 20 fractions over 5 weeks (MHRT). The endpoint of the present study was the development of any episode or grade of macroscopic hematuria. The median follow-up period was 93 months (range 6-143). Results: Macroscopic hematuria was reported by 25 of 168 patients (14.9%). The actuarial estimate of hematuria at 8 years was 17.0% (95% confidence interval [CI] 10.7%-23.3%). The number of patients with hematuria was 6 and 19 in the CFRT and MHRT arms, respectively, for an actuarial 8-year estimate of 9.7% and 24.3%, respectively (hazard ratio 3.468, 95% CI 1.385-8.684; P=.008). Overall, 8 of 25 patients were found to have biopsy-proven urothelial carcinoma (3 in the CFRT arm and 5 in the MHRT arm; P=.27). Thus, the 8-year actuarial incidence of macroscopic hematuria (after censoring urothelial cancer–related episodes) was 4.1% and 18.2% after CFRT and MHRT, respectively (hazard ratio 4.961, 95% CI 1.426-17.263; P=.012). The results were confirmed by multivariate analysis after accounting for several patient-, treatment-, and tumor-related covariates. Conclusions: MHRT was associated with a statistically significant increased risk of macroscopic hematuria compared with CFRT.

  18. Grasping the second law of thermodynamics at university: The consistency of macroscopic and microscopic explanations

    Directory of Open Access Journals (Sweden)

    Risto Leinonen

    2015-09-01

    Full Text Available [This paper is part of the Focused Collection on Upper Division Physics Courses.] This study concentrates on evaluating the consistency of upper-division students’ use of the second law of thermodynamics at macroscopic and microscopic levels. Data were collected by means of a paper and pencil test (N=48 focusing on the macroscopic and microscopic features of the second law concerned with heat transfer processes. The data analysis was based on a qualitative content analysis where students’ responses to the macroscopic- and microscopic-level items were categorized to provide insight into the consistency of the students’ ideas; if students relied on the same idea at both levels, they ended up in the same category at both levels, and their use of the second law was consistent. The most essential finding is that a majority of students, 52%–69% depending on the physical system under evaluation, used the second law of thermodynamics consistently at macroscopic and microscopic levels; approximately 40% of the students used it correctly in terms of physics while others relied on erroneous ideas, such as the idea of conserving entropy. The most common inconsistency harbored by 10%–15% of the students (depending on the physical system under evaluation was students’ tendency to consider the number of accessible microstates to remain constant even if the entropy was stated to increase in a similar process; other inconsistencies were only seen in the answers of a few students. In order to address the observed inconsistencies, we would suggest that lecturers should utilize tasks that challenge students to evaluate phenomena at macroscopic and microscopic levels concurrently and tasks that would guide students in their search for contradictions in their thinking.

  19. Step-by-step application methodology in practical KEPCO 22.9kV bus-bar system

    International Nuclear Information System (INIS)

    Yoon, Jae-young; Lee, Seung-yeol

    2010-01-01

    With the increase of power demand and the progress of power industry deregulation, the transmission and distribution systems will have more complicated problems by the influence of curtailing investment and the NIMBY phenomena in overall power systems. [1-2] It is expected that the route length per MW demand of South Korea will decrease gradually from 0.6[C-km/MW] to 0.53[C-km/MW] in 2010.[3] This comes up to a real serious problem from system planning and operation viewpoints. HTS technologies related to power system have properties to solve these complex transmission and distribution constraints, especially for metropolitan area, in the future. As the HTS technology has developed, the HTS cable technology can be the most effective alternative to solve the future expected power network constraints. This paper describes the application methodology of developing 22.9kV HTS cable by CAST for practical distribution system. 22.9kV HTS cable under development with step-by-step application methodology can substitute the existing and planning conventional 154kV cable.[4-5] If this scheme is applied, part of downtown 154kV substation of metropolitan city such as Seoul can be changed into 22.9kV switching station. Additionally, it can give huge economic, environmental benefits to all of the concerned authorities.

  20. 30 kV/10 mA solid state anode modulator for gyrotron plasma heating: design issues and results

    International Nuclear Information System (INIS)

    Fasel, D.; Lucia, C.; Ganuza, D.; Doyharzabal, I.

    2001-01-01

    Three 30 kV/10 mA solid state pulsed modulators have been delivered to the CRPP in Lausanne, by the company JEMA. Each modulator supplies the anode grid of a triode type gyrotron, used for heating purpose at the third harmonic in the TCV Tokamak. The main parameters of the final design are: the use of solid state technology, a floating output referred to the -80 kV of the gyrotron cathode potential, an output voltage range of -5 to 30 kV, 1 kHz square and sinusoidal modulation, fast switching off to -5 kV (10 μs) and pulsed operation (duty cycle of 1%). After studying and testing a solution based on regulated Mosfet transistors in series, a more stable alternative has been adopted. The final topology consists of a rectifier fed from an insulated 230 V input, a chopper, two inverter steps (for +30 and -5 kV) supplying two diode rectifiers bridges through HV transformers with two switches which commute the load to the positive or negative voltage, connected in series. This article presents the most significant aspects of the design, with special emphasis on the control principle. The final results will be presented in the context of normal operation, supplying a triode gyrotron

  1. Comparison of the quality of the chest film between digital radiography and conventional high kV radiography

    International Nuclear Information System (INIS)

    Zeng Qingsi; Cen Renli; Chen Ling; He Jianxun; Lin Hanfei

    2003-01-01

    Objective: To evaluate the quality and usefulness of direct digital radiography system in roentgenogram of chest in clinical practice. Methods: 1000 cases of chest roentgenograms with digital radiography and high kV conventional radiography were selected for analysis by 3 senior radiologists. Results: 1. With digital radiography system, the quality of chest film was assessed as grade A in 50.6%, grade B in 38.5%, grade C in 10.9%, and no waste film. 2. With conventional high kV radiography, the quality of chest film was assessed as grade A in 41.1%, grade B in 44.1%, grade C in 13.3%, and waste film in 1.5%. The direct digital radiography was statistically superior to the conventional high kV radiography. 3. The fine structure of the lungs could be revealed in 100.0% of chest roentgenogram with direct digital radiograph system, which was significantly higher than that acquired with the conventional high KV radiography (78.6%, P < 0.001). Conclusion: Direct digital radiography could provide the chest film with better quality than that with the conventional high kV radiography. The direct digital radiography system is easy to operate, fast in capturing imaging and could provide post-processing techniques, which will facilitate the accurate diagnosis of chest radiography

  2. Localization and function of the Kv3.1b subunit in the rat medulla oblongata: focus on the nucleus tractus solitarii

    Science.gov (United States)

    Dallas, Mark L; Atkinson, Lucy; Milligan, Carol J; Morris, Neil P; Lewis, David I; Deuchars, Susan A; Deuchars, Jim

    2005-01-01

    The voltage-gated potassium channel subunit Kv3.1 confers fast firing characteristics to neurones. Kv3.1b subunit immunoreactivity (Kv3.1b-IR) was widespread throughout the medulla oblongata, with labelled neurones in the gracile, cuneate and spinal trigeminal nuclei. In the nucleus of the solitary tract (NTS), Kv3.1b-IR neurones were predominantly located close to the tractus solitarius (TS) and could be GABAergic or glutamatergic. Ultrastructurally, Kv3.1b-IR was detected in NTS terminals, some of which were vagal afferents. Whole-cell current-clamp recordings from neurones near the TS revealed electrophysiological characteristics consistent with the presence of Kv3.1b subunits: short duration action potentials (4.2 ± 1.4 ms) and high firing frequencies (68.9 ± 5.3 Hz), both sensitive to application of TEA (0.5 mm) and 4-aminopyridine (4-AP; 30 μm). Intracellular dialysis of an anti-Kv3.1b antibody mimicked and occluded the effects of TEA and 4-AP in NTS and dorsal column nuclei neurones, but not in dorsal vagal nucleus or cerebellar Purkinje cells (which express other Kv3 subunits, but not Kv3.1b). Voltage-clamp recordings from outside-out patches from NTS neurones revealed an outward K+ current with the basic characteristics of that carried by Kv3 channels. In NTS neurones, electrical stimulation of the TS evoked EPSPs and IPSPs, and TEA and 4-AP increased the average amplitude and decreased the paired pulse ratio, consistent with a presynaptic site of action. Synaptic inputs evoked by stimulation of a region lacking Kv3.1b-IR neurones were not affected, correlating the presence of Kv3.1b in the TS with the pharmacological effects. PMID:15528247

  3. A polyether biotoxin binding site on the lipid-exposed face of the pore domain of Kv channels revealed by the marine toxin gambierol

    Science.gov (United States)

    Kopljar, Ivan; Labro, Alain J.; Cuypers, Eva; Johnson, Henry W. B.; Rainier, Jon D.; Tytgat, Jan; Snyders, Dirk J.

    2009-01-01

    Gambierol is a marine polycyclic ether toxin belonging to the group of ciguatera toxins. It does not activate voltage-gated sodium channels (VGSCs) but inhibits Kv1 potassium channels by an unknown mechanism. While testing whether Kv2, Kv3, and Kv4 channels also serve as targets, we found that Kv3.1 was inhibited with an IC50 of 1.2 ± 0.2 nM, whereas Kv2 and Kv4 channels were insensitive to 1 μM gambierol. Onset of block was similar from either side of the membrane, and gambierol did not compete with internal cavity blockers. The inhibition did not require channel opening and could not be reversed by strong depolarization. Using chimeric Kv3.1–Kv2.1 constructs, the toxin sensitivity was traced to S6, in which T427 was identified as a key determinant. In Kv3.1 homology models, T427 and other molecular determinants (L348, F351) reside in a space between S5 and S6 outside the permeation pathway. In conclusion, we propose that gambierol acts as a gating modifier that binds to the lipid-exposed surface of the pore domain, thereby stabilizing the closed state. This site may be the topological equivalent of the neurotoxin site 5 of VGSCs. Further elucidation of this previously undescribed binding site may explain why most ciguatoxins activate VGSCs, whereas others inhibit voltage-dependent potassium (Kv) channels. This previously undescribed Kv neurotoxin site may have wide implications not only for our understanding of channel function at the molecular level but for future development of drugs to alleviate ciguatera poisoning or to modulate electrical excitability in general. PMID:19482941

  4. The 12th 735-kV transmission line project: Hydro-Quebec network

    International Nuclear Information System (INIS)

    1992-01-01

    Hydro-Quebec is proposing to construct a 735-kV transmission line from the Chissibi station near the LG3 hydroelectric power plant to the Jacques-Cartier station near Quebec City. The width of the right-of-way will generally be 90 m and it is intended to install the line in two stages. The Chissibi-Chibougamau section should enter service in 1993 and the Chibougamau-Cartier section in 1994. The cost of the line is estimated at $1.21 billion, of which $900 million is for line construction and $310 million for station equipment. Prospective corridors for the line route have been selected, portions of which enable twinning with Hydro-Quebec's existing 9th 735-kV line. A series of hearings on the environmental and other impacts of the power line project was held by the Bureau d'audiences publiques sur l'environnement and results are summarized along with the views of the Bureau. The summary describes the justification for the project, the choice of the transmission line route, the evaluation of the impacts of the project on the natural and human environments, health effects due to magnetic fields, and effects on the economic development of northern Quebec. Recommendations are given for mitigating the impacts of the project. 13 refs., 8 figs., 2 tabs

  5. Flatiron-Erie 115kV transmission line project, Larimer, Weld and Boulder Counties, Colorado

    International Nuclear Information System (INIS)

    1993-05-01

    Western Area Power Administration (Western) proposes to uprate its existing 115-kV Flatiron-Erie transmission line. The line is located in Larimer, Weld and Boulder Counties, Colorado, and passes through the City of Longmont. The line connects Flatiron Substation and several of the substations supplying Longmont. It is a single circuit 115-kV line, 31.5 miles long, and was built in 1950-51 on a 75-foot wide right-of-way (ROW) using wood H-frame structures. Western proposes to build 27 new structures along the line, to replace or modify 45 of the existing structures and to remote 11 of them. Many of these additions and changes would involve structures that are approximately 5 to 15 feet taller than the existing ones. The existing conductors and ground wires would remain in place. The purpose of these actions would be to allow the power carrying capability of the line to be increased and to replace deteriorating/structural members. Western would be the sole participant in the proposed project. This report gives an analysis of the study area environment and the development of alternative routes. An assessment is presented of the impacts of the primary alternative routes. The environmental consequences of this project are addressed

  6. An operational 150 kV microfocus rod anode X-ray system for nondestructive testing

    International Nuclear Information System (INIS)

    Fontijn, E.A.

    1978-01-01

    This paper describes an operational state of the art 150 kV microfocus rod anode X-ray system having ultra-high radiographic resolution capabilities. A cocal spot size of 0.050 mm is provided. Heretofore unattainable long rod anode lengths coupled with very small diameters are now possible using mini-magnetic lens technology. Over-all rod anode diameters as small as 9 mm with useful lengths of 1 m or more are possible, permitting panoramic inspections where previously only lower resolution radioisotope radiographic techniques were possible. Radiographic sensitivity of better than 1% has been reported with film-focal-distances on the order of 8 mm through 3 mm of steel. The system has been successfully applied to steam generator and heat exchanger tube-to-tubesheet weldments in both Europe and the USA. Other application areas include marine and aircraft jet engine inspection and numerous other applications where high reliability requirements indicate the use of a ultra-sensitive radiographic technique as is routinely demonstrated with the 150 kV Microfocus Rod Anode X-ray System. (orig.) [de

  7. 100 kV solid-state switch for fusion heating systems

    International Nuclear Information System (INIS)

    Beaumont, B.; Bertrand, E.; Brugnetti, R.; Chatroux, D.; Kazarian, F.; Milly, R.; Prou, M.; Rigole, H.

    2005-01-01

    Power switching in RF heating systems is a delicate function as it is often linked to high power tube protection. In most RF systems, the end stage power tube is fed by a high voltage power supply (HVPS), which connection to the tube has to be interrupted in case of arc suspicion. The amount of energy that is allowable to be dissipated in the arc is in the range of 10-50 J, to limit the degradations observed on the tube structures. The protection function is usually performed by a crowbar. Furthermore, the HVPS is often shared by several power tubes, and the loss of all the power from the group of tubes is to be avoided to minimize the perturbation on the plasma experiment. A description of a 40 kV thyristor based crowbar and a 100 kV, 25 A MOSFET switch is given, as well as the contours of the existing components for high power switching applications. By combining small components, such as thyristors or MOSFET, in matrix, highly compact and reliable units have been built and implemented in Tore Supra RF systems

  8. Trailing (L5) Neptune Trojans: 2004 KV18 and 2008 LC18

    International Nuclear Information System (INIS)

    Guan Pu; Zhou Liyong; Li Jian

    2012-01-01

    The population of Neptune Trojans is believed to be bigger than that of Jupiter Trojans and that of asteroids in the main belt, although only eight members of this distant asteroid swarm have been observed up to now. Six leading Neptune Trojans around the Lagrange point L 4 discovered earlier have been studied in detail, but two trailing ones found recently around the L 5 point, 2004 KV18 and 2008 LC18, have not yet been investigated. We report our investigations on the dynamical behaviors of these two new Neptune Trojans. Our calculations show that the asteroid 2004 KV18 is a temporary Neptune Trojan. Most probably, it was captured into the trailing Trojan cloud no earlier than 2.03 × 10 5 yr ago, and it will not maintain this position later than 1.65 × 10 5 yr in the future. Based on the statistics from our orbital simulations, we argue that this object is more like a scattered Kuiper belt object. By contrast, the orbit of 2008 LC18 is much more stable. Among the clone orbits spreading within the orbital uncertainties, a considerable portion of clones may survive on the L 5 tadpole orbits for 4 Gyr. The strong dependence of the stability on the semimajor axis and resonant angle suggests that further observations are badly required to constrain the orbit in the stable region. We also discuss the implications of the existence and dynamics of these two trailing Trojans over the history of the solar system.

  9. Engineering of beam direct conversion for a 120-kV, 1-MW ion beam

    International Nuclear Information System (INIS)

    Barr, W.L.; Doggett, J.N.; Hamilton, G.W.; Kinney, J.D.; Moir, R.W.

    1977-01-01

    Practical systems for beam direct conversion are required to recover the energy from ion beams at high efficiency and at very high beam power densities in the environment of a high-power, neutral-injection system. Such an experiment is now in progress using a 120-kV beam with a maximum total current of 20 A. After neutralization, the H + component to be recovered will have a power of approximately 1MW. A system testing these concepts has been designed and tested at 15 kV, 2 kW in preparation for the full-power tests. The engineering problems involved in the full-power tests affect electron suppression, gas pumping, voltage holding, diagnostics, and measurement conditions. Planning for future experiments at higher power includes the use of cryopumping and electron suppression by a magnetic field rather than by an electrostatic field. Beam direct conversion for large fusion experiments and reactors will save millions of dollars in the cost of power supplies and electricity and will dispose of the charged beam under conditions that may mot be possible by other techniques

  10. California-Oregon 500-kV transmission line development of design criteria

    International Nuclear Information System (INIS)

    Simpson, K.D.

    1990-01-01

    The California-Oregon Transmission Project (COTP) encompassed the design and construction of a third 500-kV ac intertie between California and the Pacific Northwest Transmission system. Sargent ampersand Lundy's (S ampersand L) scope of work in the COTP includes the design of approximately 150 miles of new single-circuit, 500-kV transmission line from southern Oregon to the vicinity of Redding, California. This paper presents the development of the design criteria for this segment of the project, which crosses diverse topographic and climatic regions. This project is an example of the increasing utilization of computers in transmission line engineering. Almost all aspects of design involved the use of the computer. Also, the development of the design criteria for this project coincided with an early release of the TLWorkstation software package by EPRI. TLWorkstation is an engineering workstation containing a family of programs for various aspects of transmission line design. This engineering software allows for increasing refinement in the design and economic optimization of transmission lines and is becoming an important design tool for transmission engineers

  11. Minimal exposure technique in the Cambridge University 600kV high resolution electron microscope

    International Nuclear Information System (INIS)

    Fryer, J.R.; Cleaver, J.R.A.; Smith, D.J.

    1980-01-01

    Radiation damage due to the incident electron beam imposes a fundamental limitation on the information obtainable by electron microscopy about organic materials; it is desirable therefore that exposure of the specimen to the electron beam should be restricted to the actual period during which the image is being recorded. A description is given of methods employed in the observation of the organic aromatic hydrocarbons quaterrylene, ovalene and coronene with the Cambridge University 600kV high resolution electron microscope (HREM). In particular, the condenser-objective mode of operation of this microscope lends itself to the use of an area-defining aperture below the second condenser lens conjugate with the specimen. Furthermore, operation at the higher accelerating voltage of this instrument could be anticipated to reduce the rate of damage, depending on the dominant beam-specimen interaction, whilst the increased width of the first broad band of the contrast transfer function of this microscope at the optimum defocus may overcome the reported resolution limitation of current 100kV microscopes for the observation of related materials. (author)

  12. Taurine activates delayed rectifier KV channels via a metabotropic pathway in retinal neurons

    Science.gov (United States)

    Bulley, Simon; Liu, Yufei; Ripps, Harris; Shen, Wen

    2013-01-01

    Taurine is one of the most abundant amino acids in the retina, throughout the CNS, and in heart and muscle cells. In keeping with its broad tissue distribution, taurine serves as a modulator of numerous basic processes, such as enzyme activity, cell development, myocardial function and cytoprotection. Despite this multitude of functional roles, the precise mechanism underlying taurine's actions has not yet been identified. In this study we report findings that indicate a novel role for taurine in the regulation of voltage-gated delayed rectifier potassium (KV) channels in retinal neurons by means of a metabotropic receptor pathway. The metabotropic taurine response was insensitive to the Cl− channel blockers, picrotoxin and strychnine, but it was inhibited by a specific serotonin 5-HT2A receptor antagonist, MDL11939. Moreover, we found that taurine enhanced KV channels via intracellular protein kinase C-mediated pathways. When 5-HT2A receptors were expressed in human embryonic kidney cells, taurine and AL34662, a non-specific 5-HT2 receptor activator, produced a similar regulation of KIR channels. In sum, this study provides new evidence that taurine activates a serotonin system, apparently via 5-HT2A receptors and related intracellular pathways. PMID:23045337

  13. Ingledow 500 kV substation : using mixed technology switchgear solutions for replacement

    Energy Technology Data Exchange (ETDEWEB)

    Wallner, C.; Glaubitz, P. [Siemens AG, Munich (Germany); Messinger, T. [British Columbia Transmission Corp., Vancouver, BC (Canada)

    2008-07-01

    The reliability of the 500 kV equipment at the Ingledow substation operated by BC Hydro Transmission System is of critical importance due to the energy interchange with the Bonneville Power Authority in the United States and the major role of the substation in serving the energy needs of British Columbia's densely populated Lower Mainland. Presently, the 500 kV switchyard includes 10 airblast circuit breakers and the associated current transformers which are all approaching their end of service-life. In response to environmental and safety concerns, the British Columbia Transmission Corporation adopted a policy whereby new oil-filled transformers are no longer acceptable, and the replacement of existing oil-filled transformers must be oil-free. The result is that the current transformers must be either bushing-type or sulphur-hexafluoride (SF6) type. The replacement strategies for the substation equipment consider economical, environmental and seismic issues. They have just as strong an influence on the decision process as the technical, operational and reliability aspects for the particular case or switchgear replacement in the transmission system. The Ingledow case demonstrates the advantages of using mixed technology switchgear, with its compact design flowing from gas insulated switchgear (GIS) for replacement of equipment in an outdoor switchyard. The advantages of the MTS in this case offer the possibility of future reconfiguration to improve the system reliability within the existing switchyard space. 3 refs., 5 figs.

  14. Engineering of beam direct conversion for a 120-kV, 1-MW ion beam

    International Nuclear Information System (INIS)

    Barr, W.L.; Doggett, J.N.; Hamilton, G.W.; Kinney, J.D.; Moir, R.W.

    1977-01-01

    Practical systems for beam direct conversion are required to recover the energy from ion beams at high efficiency and at very high beam power densities in the environment of a high-power, neutral-injection system. Such an experiment is now in progress using a 120-kV beam with a maximum total current of 20 A. After neutralization, the H + component to be recovered will have a power of approximately 1 MW. A system testing these concepts has been designed and tested at 15 kV, 2 kW in preparation for the full-power tests. The engineering problems involved in the full-power tests affect electron suppression, gas pumping, voltage holding, diagnostics, and measurement conditions. Planning for future experiments at higher power includes the use of cryopumping and electron suppression by a magnetic field rather than by an electrostatic field. Beam direct conversion for large fusion experiments and reactors will save millions of dollars in the cost of power supplies and electricity and will dispose of the charged beam under conditions that may not be possible by other techniques

  15. Image quality at low tube voltage (70 kV) and sinogram-affirmed iterative reconstruction for computed tomography in infants with congenital heart disease

    International Nuclear Information System (INIS)

    Nakagawa, Motoo; Ozawa, Yoshiyuki; Sakurai, Keita; Shimohira, Masashi; Shibamoto, Yuta; Ohashi, Kazuya; Asano, Miki; Yamaguchi, Sachiko

    2015-01-01

    Lower tube voltage has advantages for CT angiography, such as improved contrast To evaluate the image quality of low-voltage (70 kV) CT for congenital heart disease and the ability of sinogram-affirmed iterative reconstruction to improve image quality. Forty-six children with congenital heart disease (median age: 109 days) were examined using dual-source CT. Scans were performed at 80 kV and 70 kV in 21 and 25 children, respectively. A nonionic iodinated contrast medium (300 mg I/ml) was used for the 80-kV protocol. The contrast medium was diluted to 75% (225 mgI/mL) with saline for the 70-kV protocol. Image noise was measured in the two protocols for each group by extracting the standard deviations of a region of interest placed on the descending aorta. We then determined whether sinogram-affirmed iterative reconstruction reduced the image noise at 70 kV. There was more noise at 70 kV than at 80 kV (29 ± 12 vs 20 ± 4.8; P < 0.01). Sinogram-affirmed iterative reconstruction with grade 4 strength settings improved the noise (20 ± 5.9; P < 0.01) for the 70-kV group. Sinogram-affirmed iterative reconstruction improved the image quality of CT in congenital heart disease. (orig.)

  16. Image quality at low tube voltage (70 kV) and sinogram-affirmed iterative reconstruction for computed tomography in infants with congenital heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Motoo; Ozawa, Yoshiyuki; Sakurai, Keita; Shimohira, Masashi; Shibamoto, Yuta [Nagoya City University Graduate School of Medical Sciences, Department of Radiology, Nagoya (Japan); Ohashi, Kazuya [Nagoya City University Hospital, Division of Central Radiology, Nagoya (Japan); Asano, Miki [Nagoya City University Graduate School of Medical Sciences, Department of Cardiovascular Surgery, Nagoya (Japan); Yamaguchi, Sachiko [Nagoya City University Graduate School of Medical Sciences, Department of Pediatrics and Neonatology, Nagoya (Japan)

    2015-09-15

    Lower tube voltage has advantages for CT angiography, such as improved contrast To evaluate the image quality of low-voltage (70 kV) CT for congenital heart disease and the ability of sinogram-affirmed iterative reconstruction to improve image quality. Forty-six children with congenital heart disease (median age: 109 days) were examined using dual-source CT. Scans were performed at 80 kV and 70 kV in 21 and 25 children, respectively. A nonionic iodinated contrast medium (300 mg I/ml) was used for the 80-kV protocol. The contrast medium was diluted to 75% (225 mgI/mL) with saline for the 70-kV protocol. Image noise was measured in the two protocols for each group by extracting the standard deviations of a region of interest placed on the descending aorta. We then determined whether sinogram-affirmed iterative reconstruction reduced the image noise at 70 kV. There was more noise at 70 kV than at 80 kV (29 ± 12 vs 20 ± 4.8; P < 0.01). Sinogram-affirmed iterative reconstruction with grade 4 strength settings improved the noise (20 ± 5.9; P < 0.01) for the 70-kV group. Sinogram-affirmed iterative reconstruction improved the image quality of CT in congenital heart disease. (orig.)

  17. On disentanglement of quantum wave functions: Answer to a comment on ''Unified dynamics for microscopic and macroscopic systems''

    International Nuclear Information System (INIS)

    Ghirardi, G.C.; Rimini, A.; Weber, T.

    1987-06-01

    It is shown that the assumption of a stochastic localization process for the quantum wave function is essentially different from the suppression of coherence over macroscopic distances arising from the interaction with the environment and allows for a conceptually complete derivation of the classical behaviour of macroscopic bodies. (author). 4 refs

  18. Dimensional verification and location of the reactive static compensator in 220 kV; Verificacion del dimensionamiento y ubicacion del compensador estatico de reactivos en 220 kV

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Krekeler, Ubaldo [Administracion Nacional de Electricidad (ANDE), Asuncion (Paraguay)]. E-mail: ufernandez@ieee.org; Cardozo Sanchez, Freddy [Mirant Americas (United States)

    2001-07-01

    This work presents a determination verification of the compensation range and the location of reactive static compensator (RSC) in 220 kV. The verification is accomplished by analyses of the RSC effects in relation to the losses, loading and system voltage stability. The needed compensation range is investigated in full details, whereas that the required conversion level is directly related to this range. It is concluded that the RSC installation, foreseen for 2002, might be postponed for 2005/10 still without reinforcements in 500 kV. The Limpio substation seems to be the more suitable location in relation to the most analysed cases.

  19. submitter Development of a 100 kW, 12.5 kV, 22 kHz and 30 kV insulated medium frequency transformer for compact and reliable medium voltage power conversion

    CERN Document Server

    Isler, Stephane; Aguglia, Davide; Bonnin, Xavier Abel

    2017-01-01

    This paper presents the critical design aspects addressed during the development of a 100 kW, 12.5 kV, 22 kHz, and 30 kV insulated medium frequency transformer used in a power converter. The transformers are used in a resonant multilevel converter topology producing HV DC voltage from a three phase 400 V AC industrial grid. The power converter is used to supply radio frequency systems in particle accelerators. Considerations about material selection, dielectric, magnetic and thermal design are discussed and experimental results on the full scale transformer and power converter are presented.

  20. Optically isolated, 2 kHz repetition rate, 4 kV solid-state pulse trigger generator.

    Science.gov (United States)

    Barnett, D H; Parson, J M; Lynn, C F; Kelly, P M; Taylor, M; Calico, S; Scott, M C; Dickens, J C; Neuber, A A; Mankowski, J J

    2015-03-01

    This paper presents the design and operation characteristics of a solid-state high voltage pulse generator. Its primary utilization is aimed at triggering a gaseous spark gap with high repeatability. Specifically, the trigger generator is designed to achieve a risetime on the order of 0.1 kV/ns to trigger the first stage, trigatron spark gap of a 10-stage, 500 kV Marx generator. The major design components are comprised of a 60 W constant current DC-DC converter for high voltage charging, a single 4 kV thyristor, a step-up pulse transformer, and magnetic switch for pulse steepening. A risetime of <30 ns and pulse magnitude of 4 kV is achieved matching the simulated performance of the design.