WorldWideScience

Sample records for direct ion orbit

  1. Direct measurement of ion phase space orbits in an electrostatic field

    International Nuclear Information System (INIS)

    Fasoli, A.; Good, T.N.; Anderegg, F.; Paris, P.J.; Tran, M.Q.; Skiff, F.; Yamada, M.

    1989-08-01

    Ion orbits are followed in phase space by means of a new scheme of the optical tagging plasma diagnostic technique. An orbit distortion for ions interacting resonantly with an ion acoustic wave is clearly observed even in the low excitation regime, where the plasma response and the corresponding macroscopic fields exhibit linear behavior. (author) 6 figs., 13 refs

  2. The 1sσ molecular orbital ionisation in asymmetric ion-atom collisions by direct Coulomb interaction

    International Nuclear Information System (INIS)

    Montenegro, E.C.; Sigaud, G.M.

    1984-11-01

    The adiabatic perturbation theory is applied to the ionisation of the 1sσ molecular orbital (MO) and extended to less adiabatic collisions by imposing an asymptotic matching with the semi-classical approximation. The transient molecular state wavefunction is modelled using the concept of an 'effective' charge for the colliding system. Through this procedure, the transition amplitudes are evaluated simulating both the relaxation of the passive electrons and the modification of the active electron wave-function, as well as their connection with the motion of the centre of charge during the collision. The direct Coulomb ionisation of the 1sσ MO is calculated for projectiles following hyperbolic paths, in terms of this 'effective' charge, using the current-vector formalism. Comparison is made with a large amount of experimental data showing good agreement. (Author) [pt

  3. On Directional Measurement Representation in Orbit Determination

    Science.gov (United States)

    2016-09-13

    Precision Orbit Determination (OD) is often critical for successful satellite operations supporting a wide variety of missions. Directional or angles only...representations. The three techniques are then compared experimentally for a geostationary and a low Earth orbit satellite using simulated data to evaluate their... Orbit Determination (OD) is often critical for successful satellite operations supporting a wide variety of missions. Precision OD involves

  4. Topology and slowing down of high energy ion orbits

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, L.G. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Porcelli, F. [Politecnico di Torino, Turin (Italy); Berk, H.L. [Texas Univ., Austin, TX (United States). Inst. for Fusion Studies

    1994-07-01

    An analysis of nonstandard guiding centre orbits is presented, which is relevant to MeV ions in a Tokamak. The orbit equation has been simplified from the start, allowing to present an analytic classification of the possible orbits. The topological transitions of the orbits during collisional slowing down are described. In particular, the characteristic equations reveal the existence of a single fixed point in the relevant phase plane, and the presence of a bifurcation curve corresponding to the locus of the pinch orbits. A significant particle inward pinch has been discovered. (authors). 7 figs.

  5. The effects of plasma shape control on the edge collisionless ion orbit loss

    Energy Technology Data Exchange (ETDEWEB)

    Wu, G. J.; Zhang, X. D.; Li, Y. D.; Sun, P. J.; Cao, G. M. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2013-10-15

    Double null magnetic configurations with different elongation κ and triangularity δ are constructed by using an analytical solution of the Grad–Shafranov equation. The ion orbit losses in plasma edge region are calculated by solving the ion guiding center orbit equation for different values of κ and δ. It is found that the ion orbit loss is larger for a smaller value of κ or δ. The variation of the ion orbit loss fraction on the magnetic surface is also studied.

  6. Determination of wave direction using an orbital following buoy

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, A.A; Almeida, A; Vaithiyanathan, R.; Vethamony, P.

    Software has been developed in FORTRAN language using a personal computer for the determination of wave direction from time series measurements of heave, pitch and roll of an orbital following buoy. The method of digital band pass filtering describ...

  7. Studies from Cassini's high-inclination orbits: ion cyclotron wave belt

    Science.gov (United States)

    Leisner, J. S.; Russell, C. T.; Dougherty, M. K.; Persoon, A. M.; Blanco-Cano, X.; Strangeway, R. J.; Cowee, M. M.

    2007-08-01

    Surrounding Saturn is a cloud of neutral water-group molecules. When these particles are ionized and accelerated by Saturn's corotating magnetized plasma, they generate ion cyclotron waves. When the inclination of the Cassini spacecraft's orbits rose to about fifty-five degrees in late 2006, new insights into the behavior of these ion cyclotron waves were obtained as the spacecraft passed through the equatorial plane, revealing latitudinal structure of the wave belt. Centered at the magnetic equator the wave amplitude grows with height in either direction, reaching a maximum at +/- 0.2 Rs and then decreasing until they disappear by +/- 0.3 Rs. Doppler shifts caused by the motion of the spacecraft reveal that these waves propagate primarily away from the equatorial plane. Using these high-inclination orbits, we study the wave growth and damping regions and their propagation characteristics. These properties give insight into the structure and ionization of Saturn's water cloud.

  8. High Cycle Life, Low Temperature Lithium Ion Battery for Earth Orbiting and Planetary Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA requires development of advanced rechargeable electrochemical battery systems for lithium ion batteries to support orbiting spacecraft and planetary missions....

  9. Direct imaging of multiple planets orbiting the star HR 8799

    Energy Technology Data Exchange (ETDEWEB)

    Marois, C; Macintosh, B; Barman, T; Zuckerman, B; Song, I; Patience, J; Lafreniere, D; Doyon, R

    2008-10-14

    Direct imaging of exoplanetary systems is a powerful technique that can reveal Jupiter-like planets in wide orbits, can enable detailed characterization of planetary atmospheres, and is a key step towards imaging Earth-like planets. Imaging detections are challenging due to the combined effect of small angular separation and large luminosity contrast between a planet and its host star. High-contrast observations with the Keck and Gemini telescopes have revealed three planets orbiting the star HR 8799, with projected separations of 24, 38, and 68 astronomical units. Multi-epoch data show counter-clockwise orbital motion for all three imaged planets. The low luminosity of the companions and the estimated age of the system imply planetary masses between 5 and 13 times that of Jupiter. This system resembles a scaled-up version of the outer portion of our Solar System.

  10. Ring/Shell Ion Distributions at Geosynchronous Orbit

    Science.gov (United States)

    Thomsen, M. F.; Denton, M. H.; Gary, S. P.; Liu, Kaijun; Min, Kyungguk

    2017-12-01

    One year's worth of plasma observations from geosynchronous orbit is examined for ion distributions that may simultaneously be subject to the ion Bernstein (IB) instability (generating fast magnetosonic waves) and the Alfvén cyclotron (AC) instability (generating electromagnetic ion cyclotron waves). Confirming past analyses, distributions with robust ∂fp(v⊥)/∂v⊥ > 0 near v|| = 0, which we denote as "ring/shell" distributions, are commonly found primarily on the dayside of the magnetosphere. A new approach to high-fidelity representation of the observed ring/shell distribution functions in a form readily suited to both analytical moment calculation and linear dispersion analysis is presented, which allows statistical analysis of the ring/shell properties. The ring/shell temperature anisotropy is found to have a clear upper limit that depends on the parallel beta of the ring/shell (β||r) in a manner that is diagnostic of the operation of the AC instability. This upper limit is only reached in the postnoon events, which are primarily produced by the energy- and pitch angle-dependent magnetic drifts of substorm-injected ions. Further, it is primarily the leading edge of such injections, where the distribution is strongly ring-like, that the AC instability appears to be operating. By contrast, the ratio of the ring energy to the Alfvén energy remains well within the range of 0.25-4.0 suitable for IB instability throughout essentially all of the events, except those that occur in denser cold plasma of the outer plasmasphere.

  11. Direct photons in heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Baeuchle, Bjoern

    2010-12-13

    Direct photon emission from heavy-ion collisions has been calculated and compared to available experimental data. Three different models have been combined to extract direct photons from different environments in a heavy-ion collision: Thermal photons from partonic and hadronic matter have been extracted from relativistic, non-viscous 3+1-dimensional hydrodynamic calculations. Thermal and non-thermal photons from hadronic interactions have been calculated from relativistic transport theory. The impact of different physics assumptions about the thermalized matter has been studied. The models used for the determination of photons from both hydrodynamic and transport calculations have been elucidated and their numerical properties tested. The origin of direct photons, itemised by emission stage, emission time, channel and baryon number density, has been investigated for various systems, as have the transverse momentum spectra and elliptic flow patterns of direct photons. Taking into account the full (vacuum) spectral function of the rho-meson decreases the direct photon emission by approximately 10% at low photon transverse momentum. In all systems that have been considered -- heavy-ion collisions at E{sub lab}=35 AGeV and 158 AGeV, (s{sub NN}){sup 1/2}=62.4 GeV, 130 GeV and 200 GeV -- thermal emission from a system with partonic degrees of freedom is greatly enhanced over that from hadronic systems, while the difference between the direct photon yields from a viscous and a non-viscous hadronic system (transport vs. hydrodynamics) is found to be very small. Predictions for direct photon emission in central U+U-collisions at 35 AGeV have been made. (orig.)

  12. Direct Laser Cooling Al{}^{+} Ion Optical Clocks

    Science.gov (United States)

    Zhang, Jie; Deng, Ke; Luo, Jun; Lu, Ze-Huang

    2017-05-01

    The Al{}+ ion optical clock is a very promising optical frequency standard candidate due to its extremely small black-body radiation shift. It has been successfully demonstrated with the indirect cooled, quantum-logic-based spectroscopy technique. Its accuracy is limited by second-order Doppler shift, and its stability is limited by the number of ions that can be probed in quantum logic processing. We propose a direct laser cooling scheme of Al{}+ ion optical clocks where both the stability and accuracy of the clocks are greatly improved. In the proposed scheme, two Al{}+ traps are utilized. The first trap is used to trap a large number of Al{}+ ions to improve the stability of the clock laser, while the second trap is used to trap a single Al{}+ ion to provide the ultimate accuracy. Both traps are cooled with a continuous wave 167 nm laser. The expected clock laser stability can reach 9.0× {10}-17/\\sqrt{τ }. For the second trap, in addition to 167 nm laser Doppler cooling, a second stage pulsed 234 nm two-photon cooling laser is utilized to further improve the accuracy of the clock laser. The total systematic uncertainty can be reduced to about 1× {10}-18. The proposed Al{}+ ion optical clock has the potential to become the most accurate and stable optical clock. Supported by the National Basic Research Program of China under Grant No 2012CB821300, the National Natural Science Foundation of China under Grant Nos 91336213, 11304109, 91536116 and 11174095, and the Program for New Century Excellent Talents by the Ministry of Education under Grant No NCET-11-0176.

  13. Broadening of ICRH produced fast ion profiles due to orbit effects

    International Nuclear Information System (INIS)

    Eriksson, L.-G.; Porcelli, F.

    1991-01-01

    In the JET tokamak, minority ions accelerated by ICRH reach energies in the MeV range. Near the plasma magnetic axis, the standard trapped particle ''banana'' orbit is distorted into a ''potato'' or ''fat banana'' orbit. The zero banana width approximation which is used in most Fokker-Planck calculations of velocity distributions of resonating ions is often not valid in JET. The inclusion of finite banana width effects will, in general, lead to a lowering of the averaged tail energy and a broadening of pressure profiles, power transfer profiles etc. A model for calculating orbit broadened profiles is presented. (Author)

  14. L-H power threshold scaling with magnetic geometry on NSTX and the role of ion orbit loss

    Science.gov (United States)

    Battaglia, D. J.; Chang, C.-S.; Kaye, S. M.; Ku, S.; Maingi, R.; NSTX Team

    2011-10-01

    The L-H power threshold (PLH) on the National Spherical Torus Experiment varies with X-point radius (RX) , plasma current (Ip) , the direction of the ion grad-B drift and the amount of lithium evaporated on the divertor surfaces. The edge Te and Ti (where Te ~ Ti) just prior to the time of the L-H transition vary with the magnetic geometry, but are fairly independent of the neutral fueling rate and lithium conditioning. These observations are consistent with the X-transport theory, which describes the mean edge radial electric field (Er) profile required to prevent non-ambipolar ion loss in a diverted plasma. A guiding-center orbit calculation in the absence of electric fields, collisions and flows provides insight into the dependence of the ion loss, and thus Er, on the magnetic geometry and edge Ti. For example, the number of ion loss orbits remains constant as RX is reduced from 0.64m to 0.47m only if the edge Ti increases by 60%. This is in agreement with self-consistent calculations of Er using the neoclassical XGC0 code and experiments that measured edge Te and Ti to be 40 - 60% larger. Similar agreement is also observed between guiding-center calculations, XGC0 results and the measured PLH versus Ip and ion grad-B direction. Supported by US DOE contracts DE-AC02-09CH11466 and DE-AC05-00OR22725.

  15. Ion trap architectures and new directions

    Science.gov (United States)

    Siverns, James D.; Quraishi, Qudsia

    2017-12-01

    Trapped ion technology has seen advances in performance, robustness and versatility over the last decade. With increasing numbers of trapped ion groups worldwide, a myriad of trap architectures are currently in use. Applications of trapped ions include: quantum simulation, computing and networking, time standards and fundamental studies in quantum dynamics. Design of such traps is driven by these various research aims, but some universally desirable properties have lead to the development of ion trap foundries. Additionally, the excellent control achievable with trapped ions and the ability to do photonic readout has allowed progress on quantum networking using entanglement between remotely situated ion-based nodes. Here, we present a selection of trap architectures currently in use by the community and present their most salient characteristics, identifying features particularly suited for quantum networking. We also discuss our own in-house research efforts aimed at long-distance trapped ion networking.

  16. Bifurcation of radial electric field in tokamak edge plasmas due to ion orbit loss

    International Nuclear Information System (INIS)

    Wu, G.J.; Zhang, X.D.

    2015-01-01

    The ion orbit loss and the formation of radial electric field Er in tokamak edge region are calculated. The ion orbit loss generates a negative Er, which in turn affects the ion loss. As a result, Er can saturates at either a low or a high value, depending on the plasma parameters. When the ion temperature in the plasma edge is higher than a threshold a self-sustaining growth in both the ion loss and Er is found, leading to a high saturation value of Er in the milliseconds time. This mechanism provides a possible explanation for the formation of the edge radial electric field during the L to H-mode transition observed in tokamak experiments. (author)

  17. Effects on Ion Cyclotron Emission of the Orbit Topology Changes from the Wave-Particle Interactions

    International Nuclear Information System (INIS)

    Hellsten, T.; Holmstroem, K.; Johnson, T.; Bergkvist, T.; Laxaback, M.

    2006-01-01

    It is known that non-relaxed distribution functions can give rise to excitation of magnetosonic waves by ion cyclotron interactions when the distribution function increases with respect to the perpendicular velocity. We have found that in a toroidal plasma also collisional relaxed distribution functions of central peaked high-energy ions can destabilise magnetosonic eigenmodes by ion cyclotron interactions, due to the change in localisation of the orbits establishing inverted distribution functions with respect to energy along the characteristics describing the cyclotron interactions. This can take place by interactions with barely co-passing and marginally trapped high-energy ions at the plasma boundary. The interactions are enhanced by tangential interactions, which can also prevent the interactions to reach the stable part of the characteristics where they interact with more deeply trapped orbits. (author)

  18. Effects on ion cyclotron emission of the orbit topology changes from the wave-particle interactions

    International Nuclear Information System (INIS)

    Hellsten, T.; Holmstroem, K.; Johnson, T.; Bergkvist, T.; Laxaback, M.

    2006-01-01

    It is known that non-relaxed distribution functions can give rise to excitation of magnetosonic waves by ion cyclotron interactions when the distribution function increases with respect to the perpendicular velocity. We have found that in a toroidal plasma also collisional relaxed distribution functions of central peaked high-energy ions can destabilise magnetosonic eigenmodes by ion cyclotron interactions, due to the change in localisation of the orbits establishing inverted distribution functions with respect to energy along the characteristics describing the cyclotron interactions. This can take place by interactions with barely co-passing and marginally trapped high-energy ions at the plasma boundary. The interactions are enhanced by tangential interactions, which can also prevent the interactions to reach the stable part of the characteristics where they interact with more deeply trapped orbits. (author)

  19. Orbits

    CERN Document Server

    Xu, Guochang

    2008-01-01

    This is the first book of the satellite era which describes orbit theory with analytical solutions of the second order with respect to all possible disturbances. Based on such theory, the algorithms of orbits determination are completely revolutionized.

  20. In-Flight Operation of the Dawn Ion Propulsion System Through Survey Science Orbit at Ceres

    Science.gov (United States)

    Garner, Charles E.; Rayman, Marc D.

    2015-01-01

    The Dawn mission, part of NASA's Discovery Program, has as its goal the scientific exploration of the two most massive main-belt objects, Vesta and Ceres. The Dawn spacecraft was launched from the Cape Canaveral Air Force Station on September 27, 2007 on a Delta-II 7925H- 9.5 (Delta-II Heavy) rocket that placed the 1218-kg spacecraft onto an Earth-escape trajectory. On-board the spacecraft is an ion propulsion system (IPS) developed at the Jet Propulsion Laboratory which will provide a total delta V of 11 km/s for the heliocentric transfer to Vesta, orbit capture at Vesta, transfer between Vesta science orbits, departure and escape from Vesta, heliocentric transfer to Ceres, orbit capture at Ceres, and transfer between Ceres science orbits. Full-power thrusting from December 2007 through October 2008 was used to successfully target a Mars gravity assist flyby in February 2009 that provided an additional delta V of 2.6 km/s. Deterministic thrusting for the heliocentric transfer to Vesta resumed in June 2009 and concluded with orbit capture at Vesta on July 16, 2011. From July 2011 through September 2012 the IPS was used to transfer to all the different science orbits at Vesta and to escape from Vesta orbit. Cruise for a rendezvous with Ceres began in September 2012 and concluded with the start of the approach to Ceres phase on December 26, 2015, leading to orbit capture on March 6, 2015. Deterministic thrusting continued during approach to place the spacecraft in its first science orbit, called RC3, which was achieved on April 23, 2015. Following science operations at RC3 ion thrusting was resumed for twenty-five days leading to arrival to the next science orbit, called survey orbit, on June 3, 2015. The IPS will be used for all subsequent orbit transfers and trajectory correction maneuvers until completion of the primary mission in approximately June 2016. To date the IPS has been operated for over 46,774 hours, consumed approximately 393 kg of xenon, and provided

  1. Orbital

    OpenAIRE

    Yourshaw, Matthew Stephen

    2017-01-01

    Orbital is a virtual reality gaming experience designed to explore the use of traditional narrative structure to enhance immersion in virtual reality. The story structure of Orbital was developed based on the developmental steps of 'The Hero's Journey,' a narrative pattern identified by Joseph Campbell. Using this standard narrative pattern, Orbital is capable of immersing the player quickly and completely for the entirety of play time. MFA

  2. Direct seawater desalination by ion concentration polarization

    Science.gov (United States)

    Kim, Sung Jae; Ko, Sung Hee; Kang, Kwan Hyoung; Han, Jongyoon

    2010-04-01

    A shortage of fresh water is one of the acute challenges facing the world today. An energy-efficient approach to converting sea water into fresh water could be of substantial benefit, but current desalination methods require high power consumption and operating costs or large-scale infrastructures, which make them difficult to implement in resource-limited settings or in disaster scenarios. Here, we report a process for converting sea water (salinity ~500 mM or ~30,000 mg l-1) to fresh water (salinity water is divided into desalted and concentrated streams by ion concentration polarization, a phenomenon that occurs when an ion current is passed through ion-selective membranes. During operation, both salts and larger particles (cells, viruses and microorganisms) are pushed away from the membrane (a nanochannel or nanoporous membrane), which significantly reduces the possibility of membrane fouling and salt accumulation, thus avoiding two problems that plague other membrane filtration methods. To implement this approach, a simple microfluidic device was fabricated and shown to be capable of continuous desalination of sea water (~99% salt rejection at 50% recovery rate) at a power consumption of less than 3.5 Wh l-1, which is comparable to current state-of-the-art systems. Rather than competing with larger desalination plants, the method could be used to make small- or medium-scale systems, with the possibility of battery-powered operation.

  3. Direct deposition of gold on silicon with focused ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Nebiker, P.W.; Doebeli, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Muehle, R. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-09-01

    Irradiation with ions at very low energies (below 500 eV) no longer induces a removal of substrate material, but the ions are directly deposited on the surface. In this way, gold has been deposited on silicon with focused ion beam exposure and the properties of the film have been investigated with atomic force microscopy and Auger electron spectroscopy. (author) 3 figs., 1 ref.

  4. Probing in-medium spin–orbit interaction with intermediate-energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Xu, Jun; Li, Bao-An

    2013-01-01

    Incorporating for the first time both the spin and isospin degrees of freedom explicitly in transport model simulations of intermediate-energy heavy-ion collisions, we observe that a local spin polarization appears during collision process. Most interestingly, it is found that the nucleon spin up–down differential transverse flow is a sensitive probe of the spin–orbit interaction, providing a novel approach to probe both the density and isospin dependence of the in-medium spin–orbit coupling that is important for understanding the structure of rare isotopes and synthesis of superheavy elements

  5. Investigation of the intermediate LK molecular orbital radiation in heavy ion-atom collisions

    International Nuclear Information System (INIS)

    Frank, W.; Kaun, K.-H.; Manfrass, P.

    1981-01-01

    The continuum consisting of an intensive low-energy and a high-energy components in heavy-ion atom collision systems with atomic numbers Z 1 , Z 2 > 28 is studied. The aim of the study is to prove that the C1 continuum cannot be caused by ridiative electron capture (REC) being molecular orbital (MO) radiation to the 2ptau level. It is shown that the comparison of the C1 yields obtained in Kr+Nb asymmetric collisions in gas and solid targets is associated with the formation of vacancies in the lower-Z collision partner and can be interpreted as quasimolecular radiation to the 2ptau orbital level. The strong suppression of the C2 component in the gas target experimets indicates that the MO radiation to the 1stau orbit is emitted preferentially in the two-collision process in symmetric and near-symmetric systems with Z 1 , Z 2 [ru

  6. Direct Fusion Drive for a Human Mars Orbital Mission

    Energy Technology Data Exchange (ETDEWEB)

    Paluszek, Michael [Princeton Satellite Systems; Pajer, Gary [Princeton Satellite Systems; Razin, Yosef [Princeton Satellite Systems; Slonaker, James [Princeton Satellite Systems; Cohen, Samuel [PPPL; Feder, Russ [PPPL; Griffin, Kevin [Princeton University; Walsh, Matthew [Princeton University

    2014-08-01

    The Direct Fusion Drive (DFD) is a nuclear fusion engine that produces both thrust and electric power. It employs a field reversed configuration with an odd-parity rotating magnetic field heating system to heat the plasma to fusion temperatures. The engine uses deuterium and helium-3 as fuel and additional deuterium that is heated in the scrape-off layer for thrust augmentation. In this way variable exhaust velocity and thrust is obtained.

  7. DFT and direct MD study of the diffusion of sodium ion on graphenes

    International Nuclear Information System (INIS)

    Tachikawa, Hiroto; Kawabata, Hiroshi

    2009-01-01

    The structures and electronic states of sodium ion (Na + ) trapped on the graphene have been investigated by means of density functional theory (DFT) calculation to elucidate the nature of interaction between Na + and the graphenes. In addition, direct molecular orbital-molecular dynamics (MO-MD) calculation [Tachikawa, J. Phys. Chem. C, 112 (2008) 10193] was applied to diffusion processes of the Na + ion on graphene. The graphene composed of 37 benzene rings was used as a model of graphene. The B3LYP/LANL2MB calculation showed that the sodium ion is stabilized in hexagonal site and is located at ca. 2.230 A from the graphene surfaces. The direct MO-MD calculation showed that the Na + ion diffuses freely on the graphene surface, but the ion did not approach the edge region due to the fact that a high potential barrier exists near the edge region. The nature of interaction between Na + and graphene was discussed on the basis of theoretical results.

  8. Separation of Rashba and Dresselhaus spin-orbit interactions using crystal direction dependent transport measurements

    International Nuclear Information System (INIS)

    Ho Park, Youn; Kim, Hyung-jun; Chang, Joonyeon; Hee Han, Suk; Eom, Jonghwa; Choi, Heon-Jin; Cheol Koo, Hyun

    2013-01-01

    The Rashba spin-orbit interaction effective field is always in the plane of the two-dimensional electron gas and perpendicular to the carrier wavevector but the direction of the Dresselhaus field depends on the crystal orientation. These two spin-orbit interaction parameters can be determined separately by measuring and analyzing the Shubnikov-de Haas oscillations for various crystal directions. In the InAs quantum well system investigated, the Dresselhaus term is just 5% of the Rashba term. The gate dependence of the oscillation patterns clearly shows that only the Rashba term is modulated by an external electric field

  9. Ribbon Ion Beam with Controlled Directionality and Local Reactive Chemistry

    Science.gov (United States)

    Biloiu, Costel; Gilchrist, Glen; Kontos, Alex; Basame, Solomon; Rockwell, Tyler; Campbell, Chris; Daniels, Kevin; Allen, Ernest; Wallace, Jay; Ballou, Jon; Hertel, Richard; Chen, Tsung-Liang; Liang, Shurong; Singh, Vikram

    2016-09-01

    A plasma processing technology designed for etch of 3D semiconductor structures is presented. The technology is characterized by controllable ion directionality and local reactive chemistry and it is based on proprietary Applied Materials - Varian Semiconductor Equipment ribbon ion beam architecture. It uses a combination of inert gas ion beam and injection of reactive chemical species at the Point-of-Use (PoU), i.e., at the wafer surface. The ion source uses an inductively coupled plasma source and a diode-type extraction optics. A beam shaping electrode allows extraction of two symmetrical ribbon-like beamlets. The ion beam has in situ controllable ion angular distribution in both mean angle and angular spread. The beam has a uniform distribution of beam current and angles over a waist exceeding 300 mm, allowing full wafer processing in one pass. Chemical compounds are delivered at PoU through linear shower heads. The reactive chemical compound delivered in this fashion maintains its molecular integrity. This result in protection of the trench side walls from deposition of etch residue and facilitates formation of volatile byproducts. The technology was used successfully for mitigation of Magnetic Tunel Junction etch residue. Other applications were this technology differentiate from present technologies are contact liner etch, Co recess, and 1D hole elongation.

  10. Full orbit simulation of collisional transport of impurity ions in the MAST spherical tokamak

    Science.gov (United States)

    Romanelli, M.; McClements, K. G.; Cross, J.; Knight, P. J.; Thyagaraja, A.; Callaghan, J.

    2011-05-01

    Transport analysis of MAST discharges indicates that collisions are an important loss mechanism in the core of a tight aspect ratio tokamak. In the strongly varying equilibrium fields of MAST many of the assumptions of drift kinetic and neoclassical theory (e.g. small plasma inverse aspect ratio and low ratio of toroidal Larmor radius to poloidal Larmor radius) are not met by all particle species and it becomes appropriate to use full orbit analysis to evaluate heat and particle fluxes. Collisional transport of impurity ions (C6+ and W20+) has been studied using a full orbit solver, CUEBIT, to integrate the test-particle dynamics. Electromagnetic fields in MAST plasma have been modelled using the cylindrical and toroidal two-fluid codes CUTIE and CENTORI. A detailed study of the scaling of the test-particle diffusivity with collisionality in the equilibrium field reveals deviations from the standard neoclassical theory, in both the Pfirsch-Schlüter and banana regimes, and difficulties in defining a local diffusivity at low collisionalities. The effect of electric and magnetic fluctuations is also briefly addressed. It is found that field fluctuations enhance the non-diffusive nature of transport. The full orbit analysis presented here predicts levels of transport and confinement times for the examined species broadly consistent with the experimental observations.

  11. Full orbit simulation of collisional transport of impurity ions in the MAST spherical tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Romanelli, M; McClements, K G; Knight, P J; Thyagaraja, A [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom); Cross, J [Department of Physics, University of Bath, Bath BA2 7AY (United Kingdom); Callaghan, J, E-mail: michele.romanelli@ccfe.ac.uk [Department of Physics, University of Oxford, New College, Oxford (United Kingdom)

    2011-05-15

    Transport analysis of MAST discharges indicates that collisions are an important loss mechanism in the core of a tight aspect ratio tokamak. In the strongly varying equilibrium fields of MAST many of the assumptions of drift kinetic and neoclassical theory (e.g. small plasma inverse aspect ratio and low ratio of toroidal Larmor radius to poloidal Larmor radius) are not met by all particle species and it becomes appropriate to use full orbit analysis to evaluate heat and particle fluxes. Collisional transport of impurity ions (C{sup 6+} and W{sup 20+}) has been studied using a full orbit solver, CUEBIT, to integrate the test-particle dynamics. Electromagnetic fields in MAST plasma have been modelled using the cylindrical and toroidal two-fluid codes CUTIE and CENTORI. A detailed study of the scaling of the test-particle diffusivity with collisionality in the equilibrium field reveals deviations from the standard neoclassical theory, in both the Pfirsch-Schlueter and banana regimes, and difficulties in defining a local diffusivity at low collisionalities. The effect of electric and magnetic fluctuations is also briefly addressed. It is found that field fluctuations enhance the non-diffusive nature of transport. The full orbit analysis presented here predicts levels of transport and confinement times for the examined species broadly consistent with the experimental observations.

  12. Direct measurement of discrete valley and orbital quantum numbers in bilayer graphene.

    Science.gov (United States)

    Hunt, B M; Li, J I A; Zibrov, A A; Wang, L; Taniguchi, T; Watanabe, K; Hone, J; Dean, C R; Zaletel, M; Ashoori, R C; Young, A F

    2017-10-16

    The high magnetic field electronic structure of bilayer graphene is enhanced by the spin, valley isospin, and an accidental orbital degeneracy, leading to a complex phase diagram of broken symmetry states. Here, we present a technique for measuring the layer-resolved charge density, from which we directly determine the valley and orbital polarization within the zero energy Landau level. Layer polarization evolves in discrete steps across 32 electric field-tuned phase transitions between states of different valley, spin, and orbital order, including previously unobserved orbitally polarized states stabilized by skew interlayer hopping. We fit our data to a model that captures both single-particle and interaction-induced anisotropies, providing a complete picture of this correlated electron system. The resulting roadmap to symmetry breaking paves the way for deterministic engineering of fractional quantum Hall states, while our layer-resolved technique is readily extendable to other two-dimensional materials where layer polarization maps to the valley or spin quantum numbers.The phase diagram of bilayer graphene at high magnetic fields has been an outstanding question, with orders possibly between multiple internal quantum degrees of freedom. Here, Hunt et al. report the measurement of the valley and orbital order, allowing them to directly reconstruct the phase diagram.

  13. Investigation of helium ion production in constricted direct current plasma ion source with layered-glows

    Science.gov (United States)

    Lee, Yuna; Chung, Kyoung-Jae; Park, Yeong-Shin; Hwang, Y. S.

    2014-02-01

    Generation of helium ions is experimentally investigated with a constricted direct current (DC) plasma ion source operated at layered-glow mode, in which electrons could be accelerated through multiple potential structures so as to generate helium ions including He2+ by successive ionization collisions in front of an extraction aperture. The helium discharge is sustained with the formation of a couple of stable layers and the plasma ball with high density is created near the extraction aperture at the operational pressure down to 0.6 Torr with concave cathodes. The ion beam current extracted with an extraction voltage of 5 kV is observed to be proportional to the discharge current and inversely proportional to the operating pressure, showing high current density of 130 mA/cm2 and power density of 0.52 mA/cm2/W. He2+ ions, which were predicted to be able to exist due to multiple-layer potential structure, are not observed. Simple calculation on production of He2+ ions inside the plasma ball reveals that reduced operating pressure and increased cathode area will help to generate He2+ ions with the layered-glow DC discharge.

  14. Direct observation of the orbital spin Kondo effect in gallium arsenide quantum dots

    Science.gov (United States)

    Shang, Ru-Nan; Zhang, Ting; Cao, Gang; Li, Hai-Ou; Xiao, Ming; Guo, Guang-Can; Guo, Guo-Ping

    2018-02-01

    Besides the spin Kondo effect, other degrees of freedom can give rise to the pseudospin Kondo effect. We report a direct observation of the orbital spin Kondo effect in a series-coupled gallium arsenide (GaAs) double quantum dot device where orbital degrees act as pseudospin. Electron occupation in both dots induces a pseudospin Kondo effect. In a region of one net spin impurity, complete spectra with three resonance peaks are observed. Furthermore, we observe a pseudo-Zeeman effect and demonstrate its electrical controllability for the artificial pseudospin in this orbital spin Kondo process via gate voltage control. The fourfold degeneracy point is realized at a specific value supplemented by spin degeneracy, indicating a transition from the SU(2) to the SU(4) Kondo effect.

  15. Passive electronic dosimeters based on direct ion storage

    International Nuclear Information System (INIS)

    Kahilainen, J.

    1995-01-01

    Using non-volatile semiconductor memories as dosimeters in radiation protection is made possible by the application of the so-called DIS (Direct Ion Storage) method, where the charge collected from a small volume of gas is directly stored in a non-volatile memory cell. This allows the construction of small and simple electronic passive dosimeters with features not available in conventional passive Film or TLD dosimeters. The basic design principles and properties of DIS dosimeters are presented and the application potential for the measurement of various categories of ionizing radiation is discussed

  16. Direct Visualization of Orbital Flipping in Volborthite by Charge Density Analysis Using Detwinned Data

    Science.gov (United States)

    Sugawara, Kento; Sugimoto, Kunihisa; Fujii, Tatsuya; Higuchi, Takafumi; Katayama, Naoyuki; Okamoto, Yoshihiko; Sawa, Hiroshi

    2018-02-01

    The distribution of d-orbital valence electrons in volborthite [Cu3V2O7(OH)2 • 2H2O] was investigated by charge density analysis of the multipole model refinement. Diffraction data were obtained by synchrotron radiation single-crystal X-ray diffraction experiments. Data reduction by detwinning of the multiple structural domains was performed using our developed software. In this study, using high-quality data, we demonstrated that the water molecules in volborthite can be located by the hydrogen bonding in cavities that consist of Kagome lattice layers of CuO4(OH)2 and pillars of V2O7. Final multipole refinements before and after the structural phase transition directly visualized the deformation electron density of the valence electrons. We successfully directly visualized the orbital flipping of the d-orbital dx2-y2, which is the highest level of 3d orbitals occupied by d9 electrons in volborthite. The developed techniques and software can be employed for investigations of structural properties of systems with multiple structural domains.

  17. Orbital properties of vanadium ions in magnetically ordered V{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Lovesey, S.; Knight, K.; Sivia, D

    2001-07-01

    Vanadium sesquioxide (V{sub 2}O{sub 3}) displays a number of electronic, magnetic and structural properties that are challenging to interpret and explain. At room temperature V{sub 2}O{sub 3} has the corundum structure with space group R3-bar-c, and it is metallic and paramagnetic. On reducing the temperature the corundum structure distorts to a monoclinic structure with space group I2/a. The structural transition in the temperature range 150 - 160K is strongly first-order and ferroelastic. Accompanying the transition are a change from metallic to insulating behaviour and the onset of anti ferromagnetic order. The metal-insulator transition is viewed as a classic Mott transition, in which spin and orbital degrees of freedom are independent. Recently, results from resonant x-ray Bragg diffraction experiments have added to the wealth of knowledge about V{sub 2}O{sub 3}. We put forward a detailed theoretical explanation of some key aspects of the observed x-ray diffraction pattern in which intensity is enhanced by the resonance at the K-edge of a vanadium ion. The success of our model in explaining the resonant x-ray diffraction data permits us to draw specific conclusions about the orbital magnetization present in V{sub 2}O{sub 3}.

  18. Direct Reaction Experimental Studies with Beams of Radioactive Tin Ions

    Energy Technology Data Exchange (ETDEWEB)

    Jones, K. L. [University of Tennessee, Knoxville (UTK); Ahn, S.H. [University of Tennessee, Knoxville (UTK); Allmond, James M [ORNL; Ayres, A. [University of Tennessee, Knoxville (UTK); Bardayan, Daniel W [ORNL; Baugher, T. [Michigan State University, East Lansing; Bazin, D. [Michigan State University, National Superconducting Cyclotron Laboratory (NSCL); Beene, James R [ORNL; Berryman, J. S. [Michigan State University, East Lansing; Bey, A. [University of Tennessee, Knoxville (UTK); Bingham, C. R. [University of Tennessee, Knoxville (UTK); Cartegni, L. [University of Tennessee, Knoxville (UTK); Chae, K. Y. [University of Tennessee, Knoxville (UTK)/Sungkyunkwan University, Korea; Cizewski, J. A. [Rutgers University; Gade, A. [Michigan State University, National Superconducting Cyclotron Laboratory (NSCL); Galindo-Uribarri, Alfredo {nmn} [ORNL; Garcia-Ruiz, R.F. [Instituut voor Kernen Stralingsfysica, KU Leuven, B-3001, Leuven, Belgium; Grzywacz, Robert Kazimierz [ORNL; Howard, Meredith E [ORNL; Kozub, R. L. [Tennessee Technological University (TTU); Liang, J Felix [ORNL; Manning, Brett M [ORNL; Matos, M. [Louisiana State University; McDaniel, S. [Michigan State University, East Lansing; Miller, D. [University of Tennessee, Knoxville (UTK); Nesaraja, Caroline D [ORNL; O' Malley, Patrick [Rutgers University; Padgett, S [University of Tennessee, Knoxville (UTK); Padilla-Rodal, Elizabeth [Universidad Nacional Autonoma de Mexico (UNAM); Pain, Steven D [ORNL; Pittman, S. T. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Radford, David C [ORNL; Ratkiewicz, Andrew J [ORNL; Schmitt, Kyle [ORNL; Smith, Michael Scott [ORNL; Stracener, Daniel W [ORNL; Stroberg, S. [Michigan State University, East Lansing; Tostevin, Jeffrey A [ORNL; Varner Jr, Robert L [ORNL; Weisshaar, D. [Michigan State University, East Lansing; Wimmer, K. [Michigan State University, National Superconducting Cyclotron Laboratory (NSCL)/Central Michigan University; Winkler, R. [Michigan State University, East Lansing

    2015-01-01

    The tin chain of isotopes provides a unique region in which to investigate the evolution of single-particle structure, spreading from N = 50 at Sn-100, through 10 stable isotopes and the N = 82 shell closure at Sn-132 out into the r-process path. Direct reactions performed on radioactive ion beams are sensitive spectroscopic tools for studying exotic nuclei. Here we present one experiment knocking out neutrons from tin isotopes that are already neutron deficient and two reactions that add a neutron to neutron-rich Sn-130. Both techniques rely on selective particle identification and the measurement of gamma rays in coincidence with charged ions. We present the goals of the two experiments and the particle identification for the channels of interest. The final results will be presented in future publications.

  19. Direct extraction of negative lithium ions from a lithium plasma

    International Nuclear Information System (INIS)

    Wada, M.; Tsuda, H.; Sasao, M.

    1990-01-01

    Negative lithium ions (Li - ) were directly extracted from a lithium plasma in a multiline cusp plasma container. A pair of permanent magnets mounted near the extractor electrode created the filter magnetic field that separated the extraction region plasma from the main discharge plasma. The plasma electrode facing the extraction region plasma was biased with respect to the other parts of the chamber wall, which acted as discharge anodes. The larger filter magnetic field resulted larger Li - current. When the bias to the plasma electrode was several volts positive against the anode potential, extracted Li - current took the maximum for a fixed strength of the filter field. These dependences of Li - upon the filter magnetic field and the plasma electrode bias are similar to the ones of negative hydrogen ions

  20. Comparison of specularly reflected gyrating ion orbits with observed shock foot thicknesses

    International Nuclear Information System (INIS)

    Livesey, W.A.; Russell, C.T.; Kennel, C.F.

    1984-01-01

    ISEE 1 and 2 flux gate magnetometer data has been used to measure the length or thickness of the ''foot'' of 60 quasi-perpendicular supercritical bow shocks along the shock normal. These bow shock crossings are contrasted with 10 quasi-perpendicular subcritical shocks which do not exhibit the precursor foot. For the supercritical shocks THETA/sub B/n, the angle between the shock normal and the upstream magnetic field, ranges from 43 0 to 88 0 . The range of THETA/sub B/n for the laminar shocks is 56 0 to 76 0 . The extent of the foot structure is compared to the orbit of an ion having solar wind velocity and undergoing simple specular reflection about the shock normal. Good quantitative agreement between the measured value of the foot and the predicted value of approx.0.7 ion gyroradii [Woods, 1971] is evident. The foot thickness normalized to this predicted value is compared to M/M/sub c/, the ratio of fast Mach number to critical fast Mach number. There is no dependence of the normalized foot thickness on Mach number other than at the transition point between subcritical and supercritical regime, M/M/sub c/ = 1. No dependence of the normalized foot thickness on upstream ion Beta is noted. The sole dependence of the normalized foot thickness on THETA/sub B/n appears to be one of simple geometry, i.e., the determination of the component of the normal solar wind perpendicular to the upstream magnetic field

  1. UREA/ammonium ion removal system for the orbiting frog otolith experiment. [ion exchange resins for water treatment during space missions

    Science.gov (United States)

    Schulz, J. R.; Anselmi, R. T.

    1976-01-01

    The feasibility of using free urease enzyme and ANGC-101 ion exchange resin to remove urea and ammonium ion for space system waste water applications was studied. Specifically examined is the prevention of urea and ammonia toxicity in a 30-day Orbiting Frog Otolith (OFO) flight experiment. It is shown that free urease enzyme used in conjunction with ANGC-101 ion-exchange resin and pH control can control urea and amonium ion concentration in unbuffered recirculating water. In addition, the resin does not adversely effect the bullfrogs by lowering the concentration of cations below critical minimum levels. Further investigations on bioburden control, frog waste excretion on an OFO diet, a trade-off analysis of methods of automating the urea/ammonium ion removal system and fabrication and test of a semiautomated breadboard were recommended as continuing efforts. Photographs of test equipment and test animals are shown.

  2. Direct nano-patterning of graphene with helium ion beams

    International Nuclear Information System (INIS)

    Naitou, Y.; Iijima, T.; Ogawa, S.

    2015-01-01

    Helium ion microscopy (HIM) was used for direct nano-patterning of single-layer graphene (SLG) on SiO 2 /Si substrates. This technique involves irradiation of the sample with accelerated helium ions (He + ). Doses of 2.0 × 10 16  He +  cm −2 from a 30 kV beam induced a metal-insulator transition in the SLG. The resolution of HIM patterning on SLG was investigated by fabricating nanoribbons and nanostructures. Analysis of scanning capacitance microscopy measurements revealed that the spatial resolution of HIM patterning depended on the dosage of He + in a non-monotonic fashion. Increasing the dose from 2.0 × 10 16 to 5.0 × 10 16  He +  cm −2 improved the spatial resolution to several tens of nanometers. However, doses greater than 1.0 × 10 17  He +  cm −2 degraded the patterning characteristics. Direct patterning using HIM is a versatile approach to graphene fabrication and can be applied to graphene-based devices

  3. On-chip spin-controlled orbital angular momentum directional coupling

    Science.gov (United States)

    Xie, Zhenwei; Lei, Ting; Si, Guangyuan; Du, Luping; Lin, Jiao; Min, Changjun; Yuan, Xiaocong

    2018-01-01

    Optical vortex beams have many potential applications in the particle trapping, quantum encoding, optical orbital angular momentum (OAM) communications and interconnects. However, the on-chip compact OAM detection is still a big challenge. Based on a holographic configuration and a spin-dependent structure design, we propose and demonstrate an on-chip spin-controlled OAM-mode directional coupler, which can couple the OAM signal to different directions due to its topological charge. While the directional coupling function can be switched on/off by altering the spin of incident beam. Both simulation and experimental measurements verify the validity of the proposed approach. This work would benefit the on-chip OAM devices for optical communications and high dimensional quantum coding/decoding in the future.

  4. Theory of nuclear heavy-ion direct transfer reactions

    International Nuclear Information System (INIS)

    Crowley, B.J.B.

    1979-01-01

    We review the distorted-wave approach to direct transfer reactions and draw attention to some of the shortcomings of current theories. We show that a reformulated form of the distorted-wave Born approximation (DWBA) for transfer can lead to important simplifications of the theory, which are valid for nuclear heavy-ion induced reactions at energies > or approx. =MeV/nucleon. In particular, in the semiclassical limit, it leads to a new and simple formula for the transfer t-matrix which includes all the essential physics while offering several important advantages over standard ''full-recoil finite-range'' DWBA. One such advantage is that the new formula is more transparent in that it is amendable to interpretation and analytical manipulation. At high-energy it is shown to reduce to one earlier deduced using eikonal-DWBA. The conditions for the validity of the new theory are discussed in detail. They are shown to be generally well satisfied for small-mass transfer between heavy-ions at energies at or above those particularly favour transfer (> or approx. =10 MeV/nucleon for transfer of valence nucleons). The restriction to small mass is not due to any recoil approximation; in fact, it is only a necessary restriction at certain energies. The theory treats recoil exactly. Consideration of the optimum dynamical conditions for transfer leads to a set of matching conditions. The presence of hitherto neglected absorption, arising from dynamical effects of poor matching, it suggested and qualitatively discussed. Condition under which such absorption may be neglected are derived. Results of numerical calculations are presented showing that the theory is capable of good agreement with standard full-recoil finite-range DWBA, and that it is capable of giving at least as good an account of experimental data for nucleon-transfer between heavy-ions at energies approx.10 MeV/nucleon

  5. Direct Detection of the Open-Shell Singlet Phenyloxenium Ion: An Atom-Centered Diradical Reacts as an Electrophile.

    Science.gov (United States)

    Du, Lili; Qiu, Yunfan; Lan, Xin; Zhu, Ruixue; Phillips, David Lee; Li, Ming-De; Dutton, Andrew S; Winter, Arthur H

    2017-10-25

    A new photoprecursor to the phenyloxenium ion, 4-methoxyphenoxypyridinium tetrafluoroborate, was investigated using trapping studies, product analysis, computational investigations, and laser flash photolysis experiments ranging from the femtosecond to the millisecond time scale. These experiments allowed us to trace the complete arc of the photophysics and photochemistry of this photoprecursor beginning with the initially populated excited states to its sequential formation of transient intermediates and ultimate formation of stable photoproducts. We find that the excited state of the photoprecursor undergoes heterolysis to generate the phenyloxenium ion in ∼2 ps but surprisingly generates the ion in its open-shell singlet diradical configuration ( 1 A 2 ), permitting an unexpected look at the reactivity of an atom-centered open-shell singlet diradical. The open-shell phenyloxenium ion ( 1 A 2 ) has a much shorter lifetime (τ ∼ 0.2 ns) in acetonitrile than the previously observed closed-shell singlet ( 1 A 1 ) phenyloxenium ion (τ ∼ 5 ns). Remarkably, despite possessing no empty valence orbitals, this open-shell singlet oxenium ion behaves as an even more powerful electrophile than the closed-shell singlet oxenium ion, undergoing solvent trapping by weakly nucleophilic solvents such as water and acetonitrile or externally added nucleophiles (e.g., azide) rather than engaging in typical diradical chemistry, such as H atom abstraction, which we have previously observed for a triplet oxenium ion. In acetonitrile, the open-shell singlet oxenium ion is trapped to generate ortho and para Ritter intermediates, one of which (para) is directly observed as a longer-lived species (τ ∼ 0.1 ms) in time-resolved resonance Raman experiments. The Ritter intermediates are ultimately trapped by either the 4-methoxypyridine leaving group (in the case of para addition) or trapped internally via an essentially barrierless rearrangement (in the case of ortho addition) to

  6. Fusion fuel ion temperature diagnostic for directly driven implosions

    Science.gov (United States)

    Chen, J. B.; Zheng, Z. J.; Peng, H. S.; Zhang, B. H.; Ding, Y. K.; Chen, M.; Chen, H. S.; Wen, T. S.

    2001-09-01

    An ultrafast quenched plastic scintillation detector was used to measure the fusion fuel ion temperature at low implosion (DT) neutron yield (5×108-3×109) in the initial experiment performed at the Shenguang II laser facility. The typical temperatures of exploding pusher targets for direct drive were around 4 keV and the uncertainties were ±15-23%. The detection efficiency of the detector to DT neutrons was calibrated at a K-400 accelerator. The time response function of the detection system was calibrated by implosion neutrons from a DT-filled capsule, which can be regarded as a δ function pulsed neutron source due to its much narrower pulse width than that of the measured neutron time-of-flight spectrum.

  7. Direct observation of orbital ordering in V 2O 3 by X-ray resonant scattering technique

    Science.gov (United States)

    Paolasini, L.; Vettier, C.; De Bergevin, F.; Yakhou, F.; Mannix, D.; Neubeck, W.; Stunault, A.; Altarelli, M.; Fabrizio, M.; Metcalf, P. A.; Honig, J. M.

    2000-06-01

    Among the materials exhibiting metal-insulator transition, vanadium sesquioxide V 2O 3 and its Cr-alloys have received most attention from the theoretical and experimental point of view. It is now widely agreed that the unusual magnetic properties can be explained by taking both orbital and spin degrees of freedom into account. Whereas many experiments give direct information on the magnetic structure, only indirect evidence suggests the existence of orbital order in cases like V 2O 3, where it is not accompanied by cooperative Jahn-Teller distortion. We have demonstrated the existence of orbital ordering in V 2O 3 by means of X-ray resonant scattering at the vanadium K-edge using tunable synchrotron radiation. The observed orbital structure confirms the interplay between orbital and magnetic order, and provides an illustration of a new experimental method to extract information on the electronic orbital occupancy in solids.

  8. Order-disorder transitions of t2g-orbitals of V3+ ions and incommensurate structural deformations in the metallic spinel CuV2S4

    International Nuclear Information System (INIS)

    Hidaka, M.; Tokiwa, N.; Wijesundera, R.P.; Awaka, J.; Nagata, S.; Park, Young Jun; Lee, Ki Bong

    2007-01-01

    Structural transitions of the spinel CuV 2 S 4 have been studied by means of X-ray diffraction using synchrotron radiation. The temperature dependence of reflections forbidden in a cubic spinel structure of Fd3m suggests that there are order-disorder transitions of 3d 2 (t 2g ) orbitals of V 3+ ions at about 75 and 210 K. An incommensurate superlattice reflection of (2+3/4,2,2+3/4) shows the structural phase transition occurring at about 90 K, in addition to the superlattice structural modulation at about 30-35 and 55 K. A reduced wavevector q=(3/4-δ,0,3/4-δ) shows the temperature dependence of the δ value from 0.015 to -0.025. A lock-in of δ=0.0 and a crossover of the δ value occur in the region of 40 to 50 K. The incommensurate structural modulation along [110], [011], and [101] directions appearing below about 90 K affects a paramagnetic spin order of V 3+ ions at about 30-35 and 55 K, in addition to the 90 K structural transition. The paramagnetic behavior is interpreted mainly by the structural deformation and the (d xy ,d yz ,d zx ) orbitals in the VS 6 octahedral chains sited along [110], [011], and [101] directions. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. THE SYNERGY OF DIRECT IMAGING AND ASTROMETRY FOR ORBIT DETERMINATION OF EXO-EARTHS

    International Nuclear Information System (INIS)

    Shao, Michael; Catanzarite, Joseph; Pan Xiaopei

    2010-01-01

    The holy grail of exoplanet searches is an exo-Earth, an Earth mass planet in the habitable zone (HZ) around a nearby star. Mass is one of the most important characteristics of a planet and can only be measured by observing the motion of the star around the planet-star center of gravity. The planet's orbit can be measured either by imaging the planet at multiple epochs or by measuring the position of the star at multiple epochs by space-based astrometry. The measurement of an exoplanet's orbit by direct imaging is complicated by a number of factors. One is the inner working angle (IWA). A space coronagraph or interferometer imaging an exo-Earth can separate the light from the planet from the light from the star only when the star-planet separation is larger than the IWA. Second, the apparent brightness of a planet depends on the orbital phase. A single image of a planet cannot tell us whether the planet is in the HZ or distinguish whether it is an exo-Earth or a Neptune-mass planet. Third is the confusion that may arise from the presence of multiple planets. With two images of a multiple planet system, it is not possible to assign a dot to a planet based only on the photometry and color of the planet. Finally, the planet-star contrast must exceed a certain minimum value in order for the planet to be detected. The planet may be unobservable even when it is outside the IWA, such as when the bright side of the planet is facing away from us in a 'crescent' phase. In this paper we address the question: 'Can a prior astrometric mission that can identify which stars have Earth-like planets significantly improve the science yield of a mission to image exo-Earths?' In the case of the Occulting Ozone Observatory, a small external occulter mission that cannot measure spectra, we find that the occulter mission could confirm the orbits of ∼4 to ∼5 times as many exo-Earths if an astrometric mission preceded it to identify which stars had such planets. In the case of an

  10. New directions for ion beam processing of optical materials

    Energy Technology Data Exchange (ETDEWEB)

    White, C.W.; Budai, J.D.; Zhu, J.G.; Withrow, S.P. [Oak Ridge National Lab., TN (United States)

    1997-03-01

    Recent developments in the use of ion implantation to modify the properties of optical materials are summarized. The use of ion implantation to form nanocrystal and quantum dots is emphasized. (author)

  11. Letter: High-mass capabilities of positive-ion and negative-ion direct analysis in real time mass spectrometry.

    Science.gov (United States)

    Gross, Jürgen H

    2016-01-01

    Of the ionic liquid 1-butyl-3-methylimidazolium (C(+)) tricyanomethide (A(-)) high-mass cluster ions of both positive ([C(n)A(n-1)](+)) and negative ([C(n-1)A(n)](-)) charge were generated and detected by direct analysis in real time (DART) Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS). After optimization of the settings of the DART ionization source and of the mass analyzer ions of m/z values unprecedented in DART-MS were detected. Thus, the upper m/z limits of positive-ion and negative-ion DART- MS were substantially expanded. Negative-ion DART-MS delivered cluster ions up to [C(15)A(16)](-), m/z 3527 (nominal mass of monoisotopic ion), while positive-ion DART-MS even yielded ions up to [C(30)A(29)](+), m/z 6784. The identification of the cluster ions is supported by their accurate mass and exact mass differences corresponding to CA between adjacent cluster ion peaks.

  12. Direct imaging of interacting vortex orbits and deformations with Lorentz transmission electron microscopy

    Science.gov (United States)

    Pollard, Shawn; Pulecio, Javier; Zhu, Yimei

    2015-03-01

    Understanding the interactions between confined, interacting magnetic quasiparticles, such as magnetic vortices, is essential towards developing both an understanding of their mutual coupling, as well as limitations for a variety of spintronic devices. However, due to a lack of spatial resolution afforded by traditional techniques, direct observation of the changes of vortex orbits in real space has been lacking. Utilizing high resolution Lorentz TEM, we image the time averaged vortex trajectories in multi-vortex permalloy rectangles and ellipses while applying an oscillating in-plane field tuned to the vortex gyrotropic mode. Using an additional in-plane DC field, we observe a transition of the vortex orbits from circular to heavily distorted as the vortices are driven together, a result of increased interaction strength in laterally coupled vortex pairs. Furthermore, in closely spaced vortex pairs, the strong coupling results in a single resonance frequency. As the vortices are moved apart, pinning effects begin to dominate, and the peak frequency is no longer singular. Micromagnetic simulations are utilized to further elucidate the coupled behavior and obtain time-resolved information of the dynamic process. Work supported by DOE-BES, Material Sciences and Engineering Division, under Contract No. DE-AC02-98CH10886.

  13. Direct photon production in heavy-ion reactions at SPS and RHIC

    Indian Academy of Sciences (India)

    ... direct photon production in heavy ion reactions is given. A brief survey of early direct photon limits from SPS experiments is presented. The first measurement of direct photons in heavy ion reactions from the WA98 collaboration is discussed and compared to theoretical calculations. An outlook on the perspective of photon ...

  14. Analysis of laser-produced heavy ions for direct plasma injection scheme

    International Nuclear Information System (INIS)

    Sakakibara, K.; Okamura, M.; Kondrashev, S.; Hattori, T.; Kashiwagi, H.; Kanesue, T.

    2006-01-01

    To accelerate highly charged intense ion beam, we have developed the direct plasma injection scheme (DPIS) with laser ion source. In this scheme an ion beam from a laser ion source is injected directly to a radio frequency quadrupole (RFQ) linac without a low energy beam transport (LEBT) line and then beam losses in the LEBT can be avoided. We achieved high current acceleration of carbon ions (60 mA) by DPIS with the RFQ specially designed for high current heavy ions. As the next step we will use heavier elements such as Al, Fe, and Ta as targets in laser ion source (using high power laser, for example, glass laser) for DPIS and will examine properties of laser-produced plasma for highly charged ion production

  15. DIRECT IMAGING CONFIRMATION AND CHARACTERIZATION OF A DUST-ENSHROUDED CANDIDATE EXOPLANET ORBITING FOMALHAUT

    Energy Technology Data Exchange (ETDEWEB)

    Currie, Thayne [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON (Canada); Debes, John [Space Telescope Science Institute, Baltimore, MD (United States); Rodigas, Timothy J. [Steward Observatory, University of Arizona, Tucson, AZ (United States); Burrows, Adam [Department of Astrophysical Sciences, Princeton University, Princeton, NJ (United States); Itoh, Yoichi [Nishi-Harima Observatory, University of Hyogo, Kobe (Japan); Fukagawa, Misato [Department of Earth and Space Sciences, Osaka University, Osaka (Japan); Kenyon, Scott J. [Smithsonian Astrophysical Observatory, Cambridge, MA (United States); Kuchner, Marc [Stellar and Exoplanets Laboratory, NASA-Goddard Space Flight Center, Greenbelt, MD (United States); Matsumura, Soko, E-mail: currie@astro.utoronto.ca [Department of Astronomy, University of Maryland-College Park, College Park, MD (United States)

    2012-12-01

    We present Subaru/IRCS J-band data for Fomalhaut and a (re)reduction of archival 2004-2006 HST/ACS data first presented by Kalas et al. We confirm the existence of a candidate exoplanet, Fomalhaut b, in both the 2004 and 2006 F606W data sets at a high signal-to-noise ratio. Additionally, we confirm the detection at F814W and present a new detection in F435W. Fomalhaut b's space motion may be consistent with it being in an apsidally aligned, non-debris ring-crossing orbit, although new astrometry is required for firmer conclusions. We cannot confirm that Fomalhaut b exhibits 0.7-0.8 mag variability cited as evidence for planet accretion or a semi-transient dust cloud. The new, combined optical spectral energy distribution and IR upper limits confirm that emission identifying Fomalhaut b originates from starlight scattered by small dust, but this dust is most likely associated with a massive body. The Subaru and IRAC/4.5 {mu}m upper limits imply M < 2 M{sub J} , still consistent with the range of Fomalhaut b masses needed to sculpt the disk. Fomalhaut b is very plausibly 'a planet identified from direct imaging' even if current images of it do not, strictly speaking, show thermal emission from a directly imaged planet.

  16. DIRECT IMAGING CONFIRMATION AND CHARACTERIZATION OF A DUST-ENSHROUDED CANDIDATE EXOPLANET ORBITING FOMALHAUT

    International Nuclear Information System (INIS)

    Currie, Thayne; Debes, John; Rodigas, Timothy J.; Burrows, Adam; Itoh, Yoichi; Fukagawa, Misato; Kenyon, Scott J.; Kuchner, Marc; Matsumura, Soko

    2012-01-01

    We present Subaru/IRCS J-band data for Fomalhaut and a (re)reduction of archival 2004-2006 HST/ACS data first presented by Kalas et al. We confirm the existence of a candidate exoplanet, Fomalhaut b, in both the 2004 and 2006 F606W data sets at a high signal-to-noise ratio. Additionally, we confirm the detection at F814W and present a new detection in F435W. Fomalhaut b's space motion may be consistent with it being in an apsidally aligned, non-debris ring-crossing orbit, although new astrometry is required for firmer conclusions. We cannot confirm that Fomalhaut b exhibits 0.7-0.8 mag variability cited as evidence for planet accretion or a semi-transient dust cloud. The new, combined optical spectral energy distribution and IR upper limits confirm that emission identifying Fomalhaut b originates from starlight scattered by small dust, but this dust is most likely associated with a massive body. The Subaru and IRAC/4.5 μm upper limits imply M J , still consistent with the range of Fomalhaut b masses needed to sculpt the disk. Fomalhaut b is very plausibly 'a planet identified from direct imaging' even if current images of it do not, strictly speaking, show thermal emission from a directly imaged planet.

  17. Ion Propulsion System and Orbit Maneuver Integration in CubeSats

    Data.gov (United States)

    National Aeronautics and Space Administration — An integrated cubesat propulsion and control system is proposed that provide three-axis attitude control and orbit maneuver capability using a micro radio-frequency...

  18. Transfer to near-Earth asteroids from a lunar orbit via Earth flyby and direct escaping trajectories

    Science.gov (United States)

    Wang, Yamin; Zhang, Yonghe; Qiao, Dong; Mao, Qingyun; Jiang, Jun

    2017-04-01

    In this paper, transfer trajectories from the Moon to near-Earth asteroids with different escaping trajectory options, Earth flyby and direct escaping, are investigated. The former executes an Earth flyby maneuver to increase the orbital energy during the transfer. The latter realizes the transfer by a single impulse at perilune. In this work, these two kinds of escaping orbits in the Earth-Moon planar circular-restricted three-body (PCRTB) system are analyzed firstly. The abilities to achieve the same Earth hyperbolic excess velocity for both orbits with minimum velocity impulse expenditure are calculated and analyzed. Then, the asteroid flyby trajectory in ephemeris model via two types of escaping orbits is designed. Asteroids 4179 Toutatis from Apollo and 3908 Nyx from Amor, represent the small and large transfer energy, respectively, are chosen as targets. The selection strategy of escaping trajectories for small and large-energy transfers is discussed.

  19. Early Phase Contingency Trajectory Design for the Failure of the First Lunar Orbit Insertion Maneuver: Direct Recovery Options

    Science.gov (United States)

    Song, Young-Joo; Bae, Jonghee; Kim, Young-Rok; Kim, Bang-Yeop

    2017-12-01

    To ensure the successful launch of the Korea pathfinder lunar orbiter (KPLO) mission, the Korea Aerospace Research Institute (KARI) is now performing extensive trajectory design and analysis studies. From the trajectory design perspective, it is crucial to prepare contingency trajectory options for the failure of the first lunar brake or the failure of the first lunar orbit insertion (LOI) maneuver. As part of the early phase trajectory design and analysis activities, the required time of flight (TOF) and associated delta-V magnitudes for each recovery maneuver (RM) to recover the KPLO mission trajectory are analyzed. There are two typical trajectory recovery options, direct recovery and low energy recovery. The current work is focused on the direct recovery option. Results indicate that a quicker execution of the first RM after the failure of the first LOI plays a significant role in saving the magnitudes of the RMs. Under the conditions of the extremely tight delta-V budget that is currently allocated for the KPLO mission, it is found that the recovery of the KPLO without altering the originally planned mission orbit (a 100 km circular orbit) cannot be achieved via direct recovery options. However, feasible recovery options are suggested within the boundaries of the currently planned delta-V budget. By changing the shape and orientation of the recovered final mission orbit, it is expected that the KPLO mission may partially pursue its scientific mission after successful recovery, though it will be limited.

  20. Impact of spin-orbit density dependent potential in heavy ion reactions forming Se nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Rajni; Sharma, Ishita; Sharma, Manoj K. [Thapar University, School of Physics and Materials Science, Patiala (India); Jain, Deepika [Mata Gujri College, Department of Physics, Fatehgarh Sahib (India)

    2017-10-15

    The Skyrme energy density formalism is employed to explore the effect of spin-orbit interaction potential by considering a two nucleon transfer process via various entrance channels such as {sup 23}Na + {sup 49}V, {sup 25}Mg + {sup 47}Ti, {sup 27}Al + {sup 45}Sc, {sup 29}Si + {sup 43}Ca and {sup 31}P + {sup 41}K, all forming the same compound system {sup 72}Se*, using both spherical as well as quadrupole deformed (β{sub 2}) nuclei. For spherical nuclei, the spin-orbit density part V{sub J} of nuclear potential remains unaffected with the transfer of two nucleons from the target to the projectile, however, show notable variation in magnitude after inclusion of deformation effects. Likewise, deformations play an important role in the spin-orbit density independent part V{sub P}, as the fusion pocket start appears, which otherwise diminish for the spherical nuclei. Further, the effect of an increase in the N/Z ratio of Se is explored on V{sub J} as well as V{sub P} and results are compared with transfer channels. In addition to this, the role of double spin-orbit parameters (W{sub 0} and W{sub 0}{sup '}) with relative contribution of the isoscalar and isovector parts of spin-orbit strength is explored in view of SkI2, SkI3 and SkI4 Skyrme forces. Beside this, the decay path of {sup 72}Se* nucleus formed in {sup 27}Al + {sup 45}Sc reaction is investigated within the framework of dynamical cluster decay model (DCM), where the nuclear proximity potential is obtained by both Skyrme energy density formalism (SEDF) and proximity pocket formula. The fusion hindrance in the {sup 27}Al + {sup 45}Sc reaction is also addressed via the barrier lowering parameter ΔV{sub B}. Finally, the contribution of spin-orbit density dependent interaction potential is estimated for the {sup 27}Al + {sup 45}Sc reaction using single (W{sub 0} or W{sub 0}{sup '}) and double spin-orbit parameters (W{sub 0} and W{sub 0}{sup '}). (orig.)

  1. Satellite orbits perturbed by direct solar radiation pressure: general expansion of the disturbing function

    International Nuclear Information System (INIS)

    Hughes, S.

    1977-01-01

    An expression is derived for the solar radiation pressure disturbing function on an Earth satellite orbit which takes into account the variation of the solar radiation flux with distance from the Sun's centre and the absorption of radiation by the satellite. This expression is then expanded in terms of the Keplerian elements of the satellite and solar orbits using Kaula's method (Astr. J.; 67:300 (1962)). The Kaula inclination functions are replaced by an equivalent set of modified Allan (Proc. R. Soc. A.; 288:60 (1965)) inclination functions. The resulting expression reduces to the form commonly used in solar radiation pressure perturbation studies (e.g. Aksnes, Cel. Mech.; 13:89 (1976)), when certain terms are neglected. If, as happens quite often in practice, a satellite's orbit is in near-resonance with certain of these neglected terms, these near-resonant terms can cause changes in the satellite's orbital elements comparable to those produced by the largest term in Aksnes's expression. A new expression for the solar radiation pressure disturbing function expansion is suggested for use in future studies of satellite orbits perturbed by solar radiation pressure. (author)

  2. Properties of Laser-Produced Highly Charged Heavy Ions for Direct Injection Scheme

    CERN Document Server

    Sakakibara, Kazuhiko; Hayashizaki, Noriyosu; Ito, Taku; Kashiwagi, Hirotsugu; Okamura, Masahiro

    2005-01-01

    To accelerate highly charged intense ion beam, we have developed the Direct Plasma Injection Scheme (DPIS) with laser ion source. In this scheme an ion beam from a laser ion source is injected directly to a RFQ linac without a low energy beam transport (LEBT) and the beam loss in the LEBT can be avoided. We achieved high current acceleration of carbon ions (60mA) by DPIS with the high current optimized RFQ. As the next setp we will use heavier elements like Ag, Pb, Al and Cu as target in LIS (using CO2, Nd-YAG or other laser) for DPIS and will examine properties of laser-produced plasma (the relationship of between charge state and laser power density, the current dependence of the distance from the target, etc).

  3. On-Orbit Demonstration of a Lithium-Ion Capacitor and Thin-Film Multijunction Solar Cells

    Science.gov (United States)

    Kukita, Akio; Takahashi, Masato; Shimazaki, Kazunori; Kobayashi, Yuki; Sakai, Tomohiko; Toyota, Hiroyuki; Takahashi, Yu; Murashima, Mio; Uno, Masatoshi; Imaizumi, Mitsuru

    2014-08-01

    This paper describes an on-orbit demonstration of the Next-generation Small Satellite Instrument for Electric power systems (NESSIE) on which an aluminum- laminated lithium-ion capacitor (LIC) and a lightweight solar panel called KKM-PNL, which has space solar sheets using thin-film multijunction solar cells, were installed. The flight data examined in this paper covers a period of 143 days from launch. We verified the integrity of an LIC constructed using a simple and lightweight mounting method: no significant capacitance reduction was observed. We also confirmed that inverted metamorphic multijunction triple-junction thin-film solar cells used for evaluation were healthy at 143 days after launch, because their degradation almost matched the degradation predictions for dual-junction thin-film solar cells.

  4. The Heavy Ion Sensor (HIS) Onboard Solar Orbiter (SOLO): Calibration Results and Science Outlook

    Science.gov (United States)

    Livi, S. A.; Lepri, S. T.; Raines, J. M.; Galvin, A.; Kistler, L. M.; Allegrini, F.; Ogasawara, K.; Collier, M. R.

    2017-12-01

    The HIS sensor has been designed and optimized to study heavy ions in the solar wind, suprathermal particles, and pickup ions in the range 0.5 to 75keV/e. This instrument will allow for unprecedented data collection of particle characteristics near the Sun at various heliolatitudes during both the quiet and active phases of the solar cycle. The close proximity and the quasi-corotation will allow for determination of the source regions on the sun for the observed events. As a result of the measurements HIS will take, we will be able to: link events on the surface of the Sun with structures in the interplanetary medium; determine the extent of gravitational settling in the expansion region of the solar wind; identify interplanetary shocks and characterize their spatial and temporal evolution; characterize the power spectra of density and velocity uctuations upstream and downstream of shocks; study the heating and dissipation mechanisms at shocks at various radial distances and latitudes; and identify the mechanisms that heat thermal solar wind ions near shocks and determine the energy partition at shocks. During the course of 2016 and 2017 HIS has been calibrated at the facility of SwRI and University of Bern, using a large energy range (0.1-450 keV), multiple masses (H-Fe), as well as charge states (1-6). The results show that HIS will meet or exceed all necessary requirements to fullfill its ambitious scientific goals.

  5. [Orbital cellulitis].

    Science.gov (United States)

    Mouriaux, F; Rysanek, B; Babin, E; Cattoir, V

    2012-01-01

    Orbital cellulitis is uncommon in ophthalmologic practice. The majority of cases arise from direct spread of sinus infection or eyelid infection. Clinically, orbital cellulitis is divided into two forms: the preseptal form, anterior to the orbital septum, and the retroseptal form, posterior to the orbital septum. Management and prognosis differ widely between the two types. The retroseptal form or "true" orbital cellulitis is a severe disease with potentially disastrous consequences for vision and survival. Clinical examination and urgent CT scanning are indispensable for correct diagnosis, evaluation of severity, surgical planning and antibiotic selection. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  6. Observations of field-aligned energetic electron and ion distributions near the magnetopause at geosynchronous orbit

    International Nuclear Information System (INIS)

    Korth, A.; Kremser, G.; Daly, P.W.; Amata, E.

    1982-01-01

    On August 28, 1978, the dayside magnetopause crossed the geosynchronous satellite GEOS 2 several times during a geomagnetically disturbed period, and clear signatures of the interconnection of field lines through the magnetopause were observed. The MPAE particle spectrometer provided high time resolution observations of the distribution of energetic electrons (E>22 keV) and ions (E>27 keV). Magnetometer data were used to determine the location of GEOS 2 relative to the magnetopause. The pitch angle distributions of ions and electrons were found to be strongly asymmetric with respect to 90 0 , and the asymmetries have been interpreted in terms of field-aligned particle streaming. Evidence is provided for the first time for electron streaming inside the magnetopause which continues for many bounce periods. It is concluded that magnetospheric field lines opened, at least for brief time intervals, as a consequence of interconnection with magnetosheath field lines. Comparisons of electron spectra provide evidence that the streaming electrons observed in the magnetosheath originate in the magnetosphere

  7. Method and apparatus for ion mobility spectrometry with alignment of dipole direction (IMS-ADD)

    Energy Technology Data Exchange (ETDEWEB)

    Shvartsburg, Alexandre A [Richland, WA; Tang, Keqi [Richland, WA; Smith, Richard D [Richland, WA

    2007-01-30

    Techniques and instrumentation are described for analyses of substances, including complex samples/mixtures that require separation prior to characterization of individual components. A method is disclosed for separation of ion mixtures and identification of ions, including protein and other macromolecular ions and their different structural isomers. Analyte ions are not free to rotate during the separation, but are substantially oriented with respect to the drift direction. Alignment is achieved by applying, at a particular angle to the drift field, a much stronger alternating electric field that "locks" the ion dipoles with moments exceeding a certain value. That value depends on the buffer gas composition, pressure, and temperature, but may be as low as .about.3 Debye under certain conditions. The presently disclosed method measures the direction-specific cross-sections that provide the structural information complementing that obtained from known methods, and, when coupled to those methods, increases the total peak capacity and specificity of gas-phase separations. Simultaneous 2-D separations by direction-specific cross sections along and orthogonally to the ion dipole direction are also possible.

  8. Errors induced in the measurement and azimuth directions of morphological features imaged on oblique Lunar Orbiter photographs

    Science.gov (United States)

    Siegal, B. S.

    1974-01-01

    Many quantitative lunar studies, e.g., the morphology and dimensions of craters, crater density and distribution, have been performed using oblique Lunar Orbiter photographs. If the inherent change in scale and azimuth direction of features imaged on these photographs are not corrected, the measurement can be in considerable error and the resulting statistical inferences may be invalid. The magnitude of this error is dependent upon: the depression angle of the camera, the flight height of the spacecraft, the focal length of the camera, and the position and orientation of the object on the ground. The errors introduced by using unrectified oblique photographs as though they were vertical photographs are examined for several Lunar Orbiter high resolution NASA LRC Enhancement photographic prints taken at various depression angles.

  9. Direct photon production in heavy-ion reactions at SPS and RHIC

    Indian Academy of Sciences (India)

    They are considerably below the heavy-ion results which indicates that a simple scaling of prompt photons as observed in pp is not sufficient to explain the direct photons in central. Pb+Pb reactions. It is also instructive to compare the γ/π0 ratio extracted from heavy-ion data to those from pp and pC in figure 3. The value in ...

  10. Direct and enantioselective α-allylation of ketones via singly occupied molecular orbital (SOMO) catalysis

    Science.gov (United States)

    Mastracchio, Anthony; Warkentin, Alexander A.; Walji, Abbas M.; MacMillan, David W. C.

    2010-01-01

    The first enantioselective organocatalytic α-allylation of cyclic ketones has been accomplished via singly occupied molecular orbital catalysis. Geometrically constrained radical cations, forged from the one-electron oxidation of transiently generated enamines, readily undergo allylic alkylation with a variety of commercially available allyl silanes. A reasonable latitude in both the ketone and allyl silane components is readily accommodated in this new transformation. Moreover, three new oxidatively stable imidazolidinone catalysts have been developed that allow cyclic ketones to successfully participate in this transformation. The new catalyst platform has also been exploited in the first catalytic enantioselective α-enolation and α-carbooxidation of ketones. PMID:20921367

  11. Direct Imaging Confirmation and Characterization of a Dust-Enshrouded Candidate Exoplanet Orbiting Fomalhaut

    OpenAIRE

    Currie, Thayne; Debes, John; Rodigas, Timothy J.; Burrows, Adam; Itoh, Yoichi; Fukagawa, Misato; Kenyon, Scott; Kuchner, Marc; Matsumura, Soko

    2012-01-01

    We present Subaru/IRCS J band data for Fomalhaut and a (re)reduction of archival 2004--2006 HST/ACS data first presented by Kalas et al. (2008). We confirm the existence of a candidate exoplanet, Fomalhaut b, in both the 2004 and 2006 F606W data sets at a high signal-to-noise. Additionally, we confirm the detection at F814W and present a new detection in F435W. Fomalhaut b's space motion may be consistent with it being in an apsidally-aligned, non debris ring-crossing orbit, although new astr...

  12. Mapping stable direct and retrograde orbits around the triple system of asteroids (45) Eugenia

    Science.gov (United States)

    Araujo, R. A. N.; Moraes, R. V.; Prado, A. F. B. A.; Winter, O. C.

    2017-12-01

    It is widely accepted that knowing the composition and the orbital evolution of asteroids might help us to understand the process of formation of the Solar system. It is also known that asteroids can represent a threat to our planet. Such an important role has made space missions to asteroids a very popular topic in current astrodynamics and astronomy studies. Taking into account the increasing interest in space missions to asteroids, especially to multiple systems, we present a study that aims to characterize the stable and unstable regions around the triple system of asteroids (45) Eugenia. The goal is to characterize the unstable and stable regions of this system and to make a comparison with the system 2001 SN263, which is the target of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) mission. A new concept was used for mapping orbits, by considering the disturbance received by the spacecraft from all perturbing forces individually. This method has also been applied to (45) Eugenia. We present the stable and unstable regions for particles with relative inclination between 0° and 180°. We found that (45) Eugenia presents larger stable regions for both prograde and retrograde cases. This is mainly because the satellites of this system are small when compared to the primary body, and because they are not close to each other. We also present a comparison between these two triple systems, and we discuss how these results can guide us in the planning of future missions.

  13. Initial assessment of the effects of energetic-ion injections in the magnetosphere due to the transport of satellite-power-system components from low earth orbit to geosynchronous earth orbit

    International Nuclear Information System (INIS)

    Curtis, S.A.; Grebowsky, J.M.

    1980-07-01

    Potentially serious environmental effects exist when cargo orbital transfer vehicle (COTV) ion propulsion is used on the scale proposed in the preliminary definition studies of the Satellite Power System. These effects of the large scale injections of ion propulsion exhaust in the plasmasphere and in the outer magnetosphere are shown to be highly model dependent with major differences existing in the predicted effects of two models - the ion cloud model and the ion sheath model. The expected total number density deposition of the propellant Ar + in the plasmasphere, the energy spectra of the deposited Ar + and time-dependent behavior of the Ar + injected into the plasmasphere by a fleet of COTV vehicles differ drastically between the two models. The major environmental effect of the former model is communication disturbance due to plasma density irregularities, in contrast to the spectacular predictions of the latter model which include power line tripping and pipe line corrosion. The ion sheath model is demonstrated to be applicable to the proposed Ar + beam physics if the beam is divergent and turbulent whereas the ion cloud model is not a realistic approximation for such a beam because the frozen-field assumption on which it is based is not valid. Finally, it is shown that the environmental effects of ion propulsion may be mitigated by the appropriate adjustment of the beam parameters

  14. Analysis of closed orbit deviations for a first direct deuteron electric dipole moment measurement at the cooler synchrotron COSY

    Science.gov (United States)

    Schmidt, V.; Lehrach, A.

    2017-07-01

    The Jülich Electric Dipole moment Investigations (JEDI) collaboration in Julich is preparing a direct EDM measurement of protons and deuterons first at the storage ring COSY (COoler SYnchrotron) and later at a dedicated storage ring. Ensuring a precise measurement, various beam and spin manipulating effects have to be considered and investigated. A distortion of the closed orbit is one of the major sources for systematic uncertainties. Therefore misalignments of magnets and residual power supply oscillations are simulated using the MAD-X code in order to analyse their effect on the orbit. The underlying model for all simulations includes the dipoles, quadrupoles and sextupoles at COSY as well as the corrector magnets and BPMs (Beam Position Monitors). Since most sextupoles are only used during beam extraction, the sextupole strengths are set to zero resulting in a linear machine. The optics is adjusted in a way that the dispersion is zero in the straight sections. The closed orbit studies are performed for deuterons with a momentum of 970 MeV/c.

  15. Unveiling magnetic interactions of ruthenium trichloride via constraining direction of orbital moments: Potential routes to realize a quantum spin liquid

    Science.gov (United States)

    Hou, Y. S.; Xiang, H. J.; Gong, X. G.

    2017-08-01

    Recent experiments reveal that the honeycomb ruthenium trichloride α -RuC l3 is a prime candidate of the Kitaev quantum spin liquid (QSL). However, there is no theoretical model which can properly describe its experimental dynamical response due to the lack of a full understanding of its magnetic interactions. Here, we propose a general scheme to calculate the magnetic interactions in systems (e.g., α -RuC l3 ) with nonnegligible orbital moments by constraining the directions of orbital moments. With this scheme, we put forward a minimal J1-K1-Γ1-J3-K3 model for α -RuC l3 and find that: (I) The third nearest neighbor (NN) antiferromagnetic Heisenberg interaction J3 stabilizes the zigzag antiferromagnetic order; (II) The NN symmetric off-diagonal exchange Γ1 plays a pivotal role in determining the preferred direction of magnetic moments and generating the spin wave gap. An exact diagonalization study on this model shows that the Kitaev QSL can be realized by suppressing the NN symmetric off-diagonal exchange Γ1 and the third NN Heisenberg interaction J3. Thus, we not only propose a powerful general scheme for investigating the intriguing magnetism of Jeff=1 /2 magnets, but also point out future directions for realizing the Kitaev QSL in the honeycomb ruthenium trichloride α -RuC l3 .

  16. Variationally localized search direction method for constrained optimization of non-orthogonal, localized orbitals in electronic structure calculations

    Science.gov (United States)

    Ruiz-Serrano, Álvaro; Skylaris, Chris-Kriton

    2013-10-01

    A new method for the constrained optimization of non-orthogonal, spatially localized orbitals using direct energy minimization techniques, in the context of electronic structure calculations, is presented. The variationally localized search direction (VLSD) method, as it was named, ensures that strict localization constraints are imposed upon the search direction vectors exactly, analytically and in a fully variational fashion. In contrast, the truncated search direction (TSD) method, of standard use in many electronic structure approaches with localization constraints, relies on the approximation that the truncated search direction vectors of the unconstrained problem resemble the exact search direction vectors of the constrained problem. With the TSD method, in order to maintain the localization constraints, a part of the pre-calculated information that is stored in the search direction vectors has to be deleted via an ad hoc, non-variational truncation step. The results on an extensive set of test molecules show that, in general, calculations with the VLSD method require less iterations to converge than with the TSD method for any size of the localization region. It was found that in calculations on certain systems where the TSD method is forced to delete a very large amount of information, the VLSD method is capable of achieving convergence in up to three times less iterations. Validation tests show that structural and electronic properties calculated with either method are accurate and in agreement with other electronic structure approaches.

  17. Strain-tolerant High Capacity Silicon Anodes via Directed Lithium Ion Transport for High Energy Density Lithium-ion Batteries

    Science.gov (United States)

    Goldman, Jason

    2012-02-01

    Energy storage is an essential component of modern technology, with applications including public infrastructure, transportation systems, and consumer electronics. Lithium-ion batteries are the preeminent form of energy storage when high energy / moderate power densities are required. Improvements to lithium-ion battery energy / power density through the adoption of silicon anodes—with approximately an order of magnitude greater gravimetric capacity than traditional carbon-based anodes--have been limited by ˜300% strains during electrochemical lithium insertion which result in short operational lifetimes. In two different systems we demonstrated improvements to silicon-based anode performance via directed lithium ion transport. The first system demonstrated a crystallographic-dependent anisotropic electrochemical lithium insertion in single-crystalline silicon anode microstructures. Exploiting this anisotropy, we highlight model silicon anode architectures that limit the maximum strain during electrochemical lithium insertion. This self-strain-limiting is a result of selecting a specific microstructure design such that during lithiation the anisotropic evolution of strain, above a given threshold, blocks further lithium intercalation. Exemplary design rules have achieved self-strain-limited charging capacities ranging from 677 mAhg-1 to 2833 mAhg-1. A second system with variably encapsulated silicon-based anodes demonstrated greater than 98% of their initial capacity after 130+ cycles. This anode also can operate stably at high energy/power densities. A lithium-ion battery with this anode was able to continuously (dis)charge in 10 minutes, corresponding to a power / energy density of ˜1460 W/kg and ˜243 Wh/kg--up to 780% greater power density and 220% higher energy density than conventional lithium-ion batteries. Anodes were also demonstrated with areal capacities of 12.7 mAh/cm^2, two orders of magnitude greater than traditional thin-film silicon anodes.[4pt

  18. Current control for magnetized plasma in direct-current plasma-immersion ion implantation

    International Nuclear Information System (INIS)

    Tang Deli; Chu, Paul K.

    2003-01-01

    A method to control the ion current in direct-current plasma-immersion ion implantation (PIII) is reported for low-pressure magnetized inductively coupled plasma. The ion current can be conveniently adjusted by applying bias voltage to the conducting grid that separates plasma formation and implantation (ion acceleration) zones without the need to alter the rf input power, gas flux, or other operating conditions. The ion current that diminishes with an increase in grid bias in magnetized plasmas can be varied from 48 to 1 mA by increasing the grid voltage from 0 to 70 V at -50 kV sample bias and 0.5 mTorr hydrogen pressure. High implantation voltage and monoenergetic immersion implantation can now be achieved by controlling the ion current without varying the macroscopic plasma parameters. The experimental results and interpretation of the effects are presented in this letter. This technique is very attractive for PIII of planar samples that require on-the-fly adjustment of the implantation current at high implantation voltage but low substrate temperature. In some applications such as hydrogen PIII-ion cut, it may obviate the need for complicated sample cooling devices that must work at high voltage

  19. Direct acceleration of ions to low and medium energies by a crossed-laser-beam configuration

    Directory of Open Access Journals (Sweden)

    Yousef I. Salamin

    2011-07-01

    Full Text Available Calculations show that 10 keV helium and carbon ions, injected midway between two identical 1 TW-power crossed laser beams of radial polarization, can be accelerated in vacuum to energies of utility in ion lithography. As examples, identical laser beams, crossed at 10° and focused to waist radii of 7.42  μm, accelerate He^{2+} and C^{6+} ions to average kinetic energies near 75 and 165 keV over distances averaging less than 7 and 6 mm, respectively. The spread in kinetic energy in both cases is less than 1% and the particle average angular deflection is less than 7 mrad. More energy-demanding industrial applications require higher-power laser beams for their direct ion laser acceleration.

  20. Helium bubbles ordering along the direction of low-energy He ions in silicon

    International Nuclear Information System (INIS)

    Reutov, V.F.; Sokhatskij, A.S.

    1998-01-01

    A phenomenon of putting in order of helium bubbles which occur during low-energy (17 keV) implantation of He ions into silicon has been discovered. The investigation was carried out by transmission electron microscopy (TEM) on the silicon samples (Cz-Si, (100), p-type, 10 Ohm x cm), irradiated at room temperature in fluence range of 3 x 10 16 - 4.5 x 10 17 cm -2 and at different falling angles of ion beam with bombarded surface. Structural modifications in silicon along He ions direction were studied with a novel 'longitudinal section' TEM technique. It has been experimentally established that: a) amorphization of silicon, implanted by He + , occurred at a damage level more than 3 dpa and began in a region of peak concentration of radiation defects; b) helium bubbles are formed exclusively in an amorphous Si (a-Si) layer; c) gas porosity development in a-Si is accompanied by bubbles ordering as along an ion-beam direction as in a cross-sectional direction; d) TEM investigation showed the presence of ion tracks with a diameter near 1 nm and a linear density equal to 10 7 cm -1 in an a-Si layer containing helium bubbles. (author)

  1. Theoretical research of electron-ion direct impact excitation cross sections for hot dense plasma

    International Nuclear Information System (INIS)

    Tian Mingfeng

    2003-01-01

    An average-atom (AA) model, Younger formula and partial wave method are employed to study the electron- ion direct impact excitation cross sections for hot dense plasma. The phenomenon of electron resonance near the excitation threshold and its mechanism are discussed. (author)

  2. Controlled fabrication of nanopores using a direct focused ion beam approach with back face particle detection.

    Science.gov (United States)

    Patterson, N; Adams, D P; Hodges, V C; Vasile, M J; Michael, J R; Kotula, P G

    2008-06-11

    We report a direct, ion drilling technique that enables the reproducible fabrication and placement of nanopores in membranes of different thickness. Using a 30 keV focused Ga ion beam column combined with an in situ, back face, multi-channelplate particle detector, nanopores are sputtered in Si(3)N(4) and W/Si(3)N(4) to have diameters as small as 12 nm. Transmission electron microscopy shows that focused ion beam-drilled holes are near-conical with the diameter decreasing from entry to exit side. By monitoring the detector signal during ion exposure, the drilled hole width can be minimized such that the exit-side diameter is smaller than the full width at half-maximum of the nominally Gaussian-shaped incident beam. Judicious choice of the beam defining aperture combined with back face particle detection allows for reproducible exit-side hole diameters between 18 and 100 nm. The nanopore direct drilling technique does not require potentially damaging broad area exposure to tailor hole sizes. Moreover, this technique successfully achieves breakthrough despite the effects of varying membrane thickness, redeposition, polycrystalline grain structure, and slight ion beam current fluctuations.

  3. Near-surface hydrogen depletion of diamond-like carbon films produced by direct ion deposition

    Science.gov (United States)

    Markwitz, Andreas; Gupta, Prasanth; Mohr, Berit; Hübner, René; Leveneur, Jerome; Zondervan, Albert; Becker, Hans-Werner

    2016-03-01

    Amorphous atomically flat diamond-like carbon (DLC) coatings were produced by direct ion deposition using a system based on a Penning ion source, butane precursor gas and post acceleration. Hydrogen depth profiles of the DLC coatings were measured with the 15N R-NRA method using the resonant nuclear reaction 1H(15N, αγ)12C (Eres = 6.385 MeV). The films produced at 3.0-10.5 kV acceleration voltage show two main effects. First, compared to average elemental composition of the film, the near-surface region is hydrogen depleted. The increase of the hydrogen concentration by 3% from the near-surface region towards the bulk is attributed to a growth model which favours the formation of sp2 hybridised carbon rich films in the film formation zone. Secondly, the depth at which the maximum hydrogen concentration is measured increases with acceleration voltage and is proportional to the penetration depth of protons produced by the ion source from the precursor gas. The observed effects are explained by a deposition process that takes into account the contributions of ion species, hydrogen effusion and preferential displacement of atoms during direct ion deposition.

  4. Near-surface hydrogen depletion of diamond-like carbon films produced by direct ion deposition

    Energy Technology Data Exchange (ETDEWEB)

    Markwitz, Andreas, E-mail: A.Markwitz@gns.cri.nz [GNS Science, Lower Hutt (New Zealand); The MacDiarmid Institute for Advanced Materials and Nanotechnology (New Zealand); Gupta, Prasanth [GNS Science, Lower Hutt (New Zealand); The MacDiarmid Institute for Advanced Materials and Nanotechnology (New Zealand); Mohr, Berit [GNS Science, Lower Hutt (New Zealand); Hübner, René [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (Germany); Leveneur, Jerome; Zondervan, Albert [GNS Science, Lower Hutt (New Zealand); Becker, Hans-Werner [RUBION, Ruhr-University Bochum (Germany)

    2016-03-15

    Amorphous atomically flat diamond-like carbon (DLC) coatings were produced by direct ion deposition using a system based on a Penning ion source, butane precursor gas and post acceleration. Hydrogen depth profiles of the DLC coatings were measured with the 15N R-NRA method using the resonant nuclear reaction {sup 1}H({sup 15}N, αγ){sup 12}C (E{sub res} = 6.385 MeV). The films produced at 3.0–10.5 kV acceleration voltage show two main effects. First, compared to average elemental composition of the film, the near-surface region is hydrogen depleted. The increase of the hydrogen concentration by 3% from the near-surface region towards the bulk is attributed to a growth model which favours the formation of sp{sup 2} hybridised carbon rich films in the film formation zone. Secondly, the depth at which the maximum hydrogen concentration is measured increases with acceleration voltage and is proportional to the penetration depth of protons produced by the ion source from the precursor gas. The observed effects are explained by a deposition process that takes into account the contributions of ion species, hydrogen effusion and preferential displacement of atoms during direct ion deposition.

  5. Ionization Mechanism of Positive-Ion Nitrogen Direct Analysis in Real Time

    Science.gov (United States)

    Song, Liguo; Chuah, Wei Chean; Lu, Xinyi; Remsen, Edward; Bartmess, John E.

    2018-02-01

    Nitrogen can be an inexpensive alternative to helium used by direct analysis in real time (DART), especially in consideration of the looming helium shortage. Therefore, the ionization mechanism of positive-ion N2 DART has been systematically investigated. Our experiments suggest that a range of metastable nitrogen species with a variety of internal energies existed and all of them were less energetic than metastable helium atoms. However, compounds with ionization energies (IE) equal to or lower than 10.2 eV (all organic compounds except the extremely small ones) can be efficiently ionized. Because N2 DART was unable to efficiently ionize ambient moisture and common organic solvents such as methanol and acetonitrile, the most important ionization mechanism was direct Penning ionization followed by self-protonation of polar compounds generating [M+H]+ ions. On the other hand, N2 DART was able to efficiently ionize ammonia, which was beneficial in the ionization of hydrogen-bonding compounds with proton affinities (PA) weaker than ammonia generating [M+NH4]+ ions and large PAHs generating [M+H]+ ions through proton transfer. N2 DART was also able to efficiently ionize NO, which led to the ionization of nonpolar compounds such as alkanes and small aromatics generating [M-(2m+1)H]+ (m=0,1…) ions. Lastly, metastable nitrogen species was also able to produce oxygen atoms, which resulted in increased oxygen adducts as the polarity of organic compounds decreased. In comparison with He DART, N2 DART was approximately one order of magnitude less sensitive in generating [M+H]+ ions, but could be more sensitive in generating [M+NH4]+ ions. [Figure not available: see fulltext.

  6. Using the Orbit Tracking Code Z3CYCLONE to Predict the Beam Produced by a Cold Cathode PIG Ion Source for Cyclotrons under DC Extraction

    CERN Document Server

    Forringer, Edward

    2005-01-01

    Experimental measurements of the emittance and luminosity of beams produced by a cold-cathode Phillips Ionization Guage (PIG) ion source for cyclotrons under dc extraction are reviewed. (The source being studied is of the same style as ones that will be used in a series of 250 MeV proton cyclotrons being constructed for cancer therapy by ACCEL Inst, Gmbh, of Bergisch Gladbach, Germany.) The concepts of 'plasma boundary' and 'plasma temperature' are presented as a useful set of parameters for describing the initial conditions used in computational orbit tracking. Experimental results for r-pr and z-pz emittance are compared to predictions from the MSU orbit tracking code Z3CYCLONE with results indicating that the code is able to predict the beam produced by these ion sources with adequate accuracy such that construction of actual cyclotrons can proceed with reasonably prudent confidence that the cyclotron will perform as predicted.

  7. Ion-orbital coupling in Car-Parrinello calculations of hydrogen-bond vibrational dynamics: Case study with the NH3-HCl dimer

    Science.gov (United States)

    Ong, S. W.; Lee, B. X. B.; Kang, H. C.

    2011-09-01

    We have performed Car-Parrinello molecular dynamics (CPMD) calculations of the hydrogen-bonded NH3-HCl dimer. Our main aim is to establish how ionic-orbital coupling in CPMD affects the vibrational dynamics in hydrogen-bonded systems by characterizing the dependence of the calculated vibrational frequencies upon the orbital mass in the adiabatic limit of Car-Parrinello calculations. We use the example of the NH3-HCl dimer because of interest in its vibrational spectrum, in particular the magnitude of the frequency shift of the H-Cl stretch due to the anharmonic interactions when the hydrogen bond is formed. We find that an orbital mass of about 100 a.u. or smaller is required in order for the ion-orbital coupling to be linear in orbital mass, and the results for which can be accurately extrapolated to the adiabatic limit of zero orbital mass. We argue that this is general for hydrogen-bonded systems, suggesting that typical orbital mass values used in CPMD are too high to accurately describe vibrational dynamics in hydrogen-bonded systems. Our results also show that the usual application of a scaling factor to the CPMD frequencies to correct for the effects of orbital mass is not valid. For the dynamics of the dimer, we find that the H-Cl stretch and the N-H-Cl bend are significantly coupled, suggesting that it is important to include the latter degree of freedom in quantum dynamical calculations. Results from our calculations with deuterium-substitution show that both these degrees of freedom have significant anharmonic interactions. Our calculated frequency for the H-Cl stretch using the Becke-exchange Lee-Yang-Parr correlation functional compares reasonably well with a previous second-order Møller-Plesset calculation with anharmonic corrections, although it is low compared to the experimental value for the dimer trapped in a neon-matrix.

  8. Ion transport membrane module and vessel system with directed internal gas flow

    Science.gov (United States)

    Holmes, Michael Jerome; Ohrn, Theodore R.; Chen, Christopher Ming-Poh

    2010-02-09

    An ion transport membrane system comprising (a) a pressure vessel having an interior, an inlet adapted to introduce gas into the interior of the vessel, an outlet adapted to withdraw gas from the interior of the vessel, and an axis; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region; and (c) one or more gas flow control partitions disposed in the interior of the pressure vessel and adapted to change a direction of gas flow within the vessel.

  9. Directional modulation of electron-ion pairs recombination in liquid argon

    Science.gov (United States)

    Cataudella, V.; de Candia, A.; De Filippis, G.; Catalanotti, S.; Cadeddu, M.; Lissia, M.; Rossi, B.; Galbiati, C.; Fiorillo, G.

    2017-12-01

    Motivated by the ongoing study of a possible directional signal in liquid argon dark matter detectors, we introduce a new model describing the recombination of electron-ion pairs in ionizing tracks in liquid argon in the presence of a drift field. The emphasis is on the three-dimensional distribution of electrons and ions and on their orientation relative to that of the electric field. We successfully apply our model to describe the angular dependence of the ionization signal of protons recently reported in measurements performed by the ArgoNeuT Collaboration with a liquid argon time projection chamber.

  10. Direct electrodeposition of Cu2Sb for lithium-ion battery anodes.

    Science.gov (United States)

    Mosby, James M; Prieto, Amy L

    2008-08-13

    We describe the direct single potential electrodeposition of crystalline Cu2Sb, a promising anode material for lithium-ion batteries, from aqueous solutions at room temperature. The use of citric acid as a complexing agent increases the solubility of antimony salts and shifts the reduction potentials of copper and antimony toward each other, enabling the direct deposition of the intermetallic compound at pH 6. Electrodeposition of Cu2Sb directly onto conducting substrates represents a facile synthetic method for the synthesis of high quality samples with excellent electrical contact to a substrate, which is critical for further battery testing.

  11. Magnetic Reconnection Processes Involving Modes Propagating in the Ion Diamagnetic Velocity Direction

    Science.gov (United States)

    Buratti, P.; Coppi, B.; Pucella, G.; Zhou, T.

    2013-10-01

    Experiments in weakly collisional plasma regimes, (e.g. neutral beam heated plasmas in the H-regime), measuring the Doppler shift associated with the plasma local rotation, have shown that the toroidal mode phase velocity vph in the frame with Er = 0 is in the direction of the ion diamagnetic velocity. For ohmically heated plasmas, with higher collisionalities, vph in the laboratory frame is in the direction of the electron diamagnetic velocity, but plasma rotation is reversed as well, and vph, in the Er = 0 frame, is in the ion diamagnetic velocity direction. Theoretically, two classes of reconnecting modes should emerge: drift-tearing modes and ``inductive modes'' that depend on the effects of a finite plasma inductivity. The former modes, with vph in the direction of the electron diamagnetic velocity, require the pre-excitation of a different kind of mode in order to become unstable in weakly collisional regimes. The second kind of modes has a growth rate associated with the relevant finite ion viscosity. A comprehensive theory is presented. Sponsored in part by the US DOE.

  12. Behaviour of direct and delayed fast ion losses during NBI on TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.; Liniers; M.

    1995-09-01

    The dependence with density and beam energy of the different kind of fast ion losses, direct and delayed, during tangential balanced NBI injection in TJ-II helical axis stellerator has been analysed. Direct losses increase with energy and a strong difference between the two injection directions appears, are produced by passing particles that loss confinement in a dew mu,sec and the influence of birth profiles produces an increase with density. Delayed losses are very well separated in time from direct ones, are produced by particles experimenting pitch angle scattering an,d, most o them, correspond to trapped particles. Are much less important than the direct ones (about 1/3), decrease slowly with energy and, with CX, increase with density (an effect of initial profile). The absorption is rather independent of energy with low values at low density in reason of high shine trough and CX losses, but reovers quickly with the density increase

  13. A gas ionisation Direct-STIM detector for MeV ion microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Norarat, Rattanaporn, E-mail: rattanaporn@rmutl.ac.th [University of Applied Sciences (HES-SO), Haute Ecole Arc Ingénierie, Eplatures-Gris 17, CH-2300 La Chaux-de-Fonds (Switzerland); Faculty of Science and Agriculture, Rajamangala University of Technology Lanna, Chiang Rai, 57120 Chiang Rai (Thailand); Department of Physics, University of Jyväskylä, P.O. Box 35, Jyväskylä FI-40014 (Finland); Guibert, Edouard; Jeanneret, Patrick; Dellea, Mario; Jenni, Josef [University of Applied Sciences (HES-SO), Haute Ecole Arc Ingénierie, Eplatures-Gris 17, CH-2300 La Chaux-de-Fonds (Switzerland); Roux, Adrien; Stoppini, Luc [Tissue Engineering Laboratory, Campus Biotech, Chemin des Mines 9, Geneva (Switzerland); Whitlow, Harry J. [University of Applied Sciences (HES-SO), Haute Ecole Arc Ingénierie, Eplatures-Gris 17, CH-2300 La Chaux-de-Fonds (Switzerland)

    2015-04-01

    Direct-Scanning Transmission Ion Microscopy (Direct-STIM) is a powerful technique that yields structural information in sub-cellular whole cell imaging. Usually, a Si p-i-n diode is used in Direct-STIM measurements as a detector. In order to overcome the detrimental effects of radiation damage which appears as a broadening in the energy resolution, we have developed a gas ionisation detector for use with a focused ion beam. The design is based on the ETH Frisch grid-less off-axis Geiger–Müller geometry. It is developed for use in a MeV ion microscope with a standard Oxford Microbeams triplet lens and scanning system. The design has a large available solid angle for other detectors (e.g. proton induced fluorescence). Here we report the performance for imaging ReNcells VM with μm resolution where energy resolutions of <24 keV fwhm could be achieved for 1 MeV protons using isobutane gas.

  14. Ion pair reinforced semi-interpenetrating polymer network for direct methanol fuel cell applications.

    Science.gov (United States)

    Fang, Chunliu; Julius, David; Tay, Siok Wei; Hong, Liang; Lee, Jim Yang

    2012-06-07

    This paper describes the synthesis of ion-pair-reinforced semi-interpenetrating polymer networks (SIPNs) as proton exchange membranes (PEMs) for the direct methanol fuel cells (DMFCs). Specifically, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO), a linear polymer proton source, was immobilized in a brominated PPO (BPPO) network covalently cross-linked by ethylenediamine (EDA). The immobilization of SPPO in the SIPN network was accomplished not only by the usual means of mechanical interlocking but also by ion pair formation between the sulfonic acid groups of SPPO and the amine moieties formed during the cross-linking reaction of BPPO with EDA. Through the ion pair interactions, the immobilization of SPPO polymer in the BPPO network was made more effective, resulting in a greater uniformity of sulfonic acid cluster distribution in the membrane. The hydrophilic amine-containing cross-links also compensated for some of the decrease in proton conductivity caused by ion pair formation. The SIPN membranes prepared as such showed good proton conductivity, low methanol permeability, good mechanical properties, and dimensional stability. Consequently, the PPO based SIPN membranes were able to deliver a higher maximum power density than Nafion, demonstrating the potential of the SIPN structure for PEM designs.

  15. Direct ion heating in overdense plasmas through the Brillouin instability driven by relativistic whistler waves

    Science.gov (United States)

    Sano, Takayoshi; Hata, Masayasu; Iwata, Natsumi; Mima, Kunioki; Sentoku, Yasuhiko

    2017-10-01

    Strong magnetic fields over kilo-Tesla have been available in the laboratory by the use of ultra-intense lasers. It would be interesting to apply those strong fields to other laser experiments such as the inertial confinement fusion and laboratory astrophysics. The characteristics of laser-plasma interactions could be modified significantly by the presence of such strong magnetic fields. We investigate electromagnetic wave propagation in overdense plasmas along the magnetic field for a right-hand circularly polarized wave by PIC simulations. Since the whistler mode has no cutoff density, it can penetrate into overdense plasmas and interact directly with charged particles there. When the external field strength is near a critical value defined by that the cyclotron frequency is equal to the laser one, it is reported that electrons are accelerated efficiently by the cyclotron resonance. However, if the field strength is far beyond the critical value, the cyclotron resonance is inefficient, while the ions gain a large amount of energy directly from the laser light owning to the Brillouin scattering. As the result, only ions are heated up selectively. We will discuss about the application of this ion heating in dense plasmas. This work was supported by JSPS KAKENHI Grant Number JP15K21767.

  16. Direct Measurement of Beam Angle in a High Current Ion Implanter

    Science.gov (United States)

    Freer, B. S.; Rubin, L. M.; Graf, M. A.; Hoglund, D. E.; Newman, D.; Ditzler, K.; Elshot, K.; Romig, T.

    2006-11-01

    We report the first device results from a new method of direct measurement and real-time control of the average angle of an ion beam in a high current ion implanter. The angle detector consists of an array of high aspect ratio slots that are mounted directly on the same process disk containing the wafers. Beam profiling is achieved by measuring the ion current through the slots versus angle as the disk is rotated perpendicular to the slots. From this profile we determine an angle offset relative to the nominal implant angle. This offset may be a result of beam steering, mechanical positioning uncertainty, or both. The disk is then reoriented if necessary to ensure that the desired beam angle with respect to the wafer is achieved. We implanted the NMOS and PMOS source/drain extension implants for several dozen lots of 90nm and 120nm NMOS and PMOS devices. We showed tightened distributions of both transistor drive currents and asymmetry of drive currents under reverse biasing for 90nm and 120nm devices manufactured on 300mm wafers after the installation of the angle detection hardware. We also observed a tightening of the yield distribution for the 120nm devices.

  17. The Gaussian Atomic Orbital Multiplied by a Field-Dependent Gauge Phase for the Hydrogen Molecular Ion in Non-aligned Magnetic Fields

    International Nuclear Information System (INIS)

    Song, Xuanyu; Li, Cun; Wang, Xiaofeng; Qiao, Haoxue

    2016-01-01

    We multiply the anisotropic Gaussian atomic orbital by a field-dependent gauge phase to describe the wave function for the hydrogen molecular ion in non-aligned magnetic fields. With the kind of basis set, the convergence of the total energy at the equilibrium distance for the 1 u state is much improved compared to the same atomic orbital without the gauge phase. For 2.35 × 10 4 ≤ B ≤ 10 7 T, better total energies of the 1 u state at the corresponding equilibrium are obtained for the deviations 15°–90° of the magnetic field relative to the molecular axis. The result also shows that, there is a transition of the equilibrium configuration from the vertical orientation to the parallel orientation with increasing field strength. (author)

  18. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole

    Science.gov (United States)

    Rodrigues, G.; Becker, R.; Hamm, R. W.; Baskaran, R.; Kanjilal, D.; Roy, A.

    2014-02-01

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged 238U40+ (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  19. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole.

    Science.gov (United States)

    Rodrigues, G; Becker, R; Hamm, R W; Baskaran, R; Kanjilal, D; Roy, A

    2014-02-01

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged (238)U(40+) (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  20. Direct Detection and Orbit Analysis of the Exoplanets HR 8799 bcd from Archival 2005 Keck/NIRC2 Data

    Science.gov (United States)

    Currie, Thayne; Fukagawa, Misato; Thalmann, Christian; Matsumura, Soko; Plavchan, Peter

    2012-01-01

    We present previously unpublished July 2005 H-band coronagraphic data of the young, planet-hosting star HR 8799 from the newly-released Keck/NIRC2 archive. Despite poor observing conditions, we detect three of the planets (HR 8799 bcd), two of them (HR 8799 bc) without advanced image processing. Comparing these data with previously published 1998-2011 astrometry and that from re-reduced October 2010 Keck data constrains the orbits of the planets. Analyzing the planets' astrometry separately, HR 8799 d's orbit is likely inclined at least 25 deg from face-on and the others may be on in inclined orbits. For semimajor axis ratios consistent with a 4:2:1 mean-motion resonance our analysis yields precise values for HR 8799 bcd's orbital parameters and strictly constrains the planets' eccentricities to be less than 0.18-0.3. However, we find no acceptable orbital solutions with this resonance that place the planets in face-on orbits; HR 8799 d shows the largest deviation from such orbits. Moreover, few orbits make HR 8799 d coplanar with b and c, whereas dynamical stability analyses used to constrain the planets' masses typically assume coplanar and/or fare.on orbits. This paper illustrates the significant science gain enabled with the release of the NIRC2 archive.

  1. Direct-indirect mixed implosion mode in heavy ion inertial fusion

    International Nuclear Information System (INIS)

    Kawata, S.; Miyazawa, K.; Kikuchi, T.; Someya, T.

    2007-01-01

    In order to realize an effective implosion, beam illumination non-uniformity on a fuel target must be suppressed less than a few percent. In this study, a direct-indirect mixture implosion mode is proposed and discussed in heavy ion beam (HIB) inertial confinement fusion (HIF) in order to release sufficient fusion energy in a robust manner. On the other hand, the HIB illumination non-uniformity depends strongly on a target displacement dz from the center of a fusion reactor chamber. In a direct-driven implosion mode, dz of ∼20 μm was tolerable, and in an indirect-implosion mode, dz of ∼100 μm was allowable. In the direct-indirect mixture mode target, a low-density foam layer is inserted, and the radiation energy is confined in the foam layer. In the foam layer, the radiation transport is expected to smooth the HIB illumination non-uniformity in the lateral direction. Two-dimensional implosion simulations are performed, and show that the HIB illumination non-uniformity is well smoothed in the direct-indirect mixture target. Our simulation results present that a large pellet displacement of approximately a few hundred microns is allowed in order to obtain a sufficient fusion energy output in HIF

  2. Direct determination of ammoniacal nitrogen in water samples using corona discharge ion mobility spectrometry.

    Science.gov (United States)

    Jafari, M T; Khayamian, T

    2008-09-15

    In this study, direct determination of ammoniacal nitrogen residues in water samples using corona discharge ion mobility spectrometry (CD-IMS) was investigated. Pyridine was used as an alternate reagent gas to enhance selectivity and sensitivity of the method. The results indicate that the limit of detection (LOD) was about 9.2x10(-3)mugmL(-1) and the linear dynamic range was obtained from 0.03 to 2.00mugmL(-1). The relative standard deviation was about 11%. Furthermore, this method was successfully applied to the direct determination of ammoniacal nitrogen in river and tap water samples and the results were compared with the Nessler method. The comparison of the results validates the potential of the proposed method as an alternative technique for the analysis of the ammoniacal nitrogen in water samples.

  3. Investigation of mixed ion fields in the forward direction for 220.5 MeV/u helium ion beams: comparison between water and PMMA targets

    Science.gov (United States)

    Aricò, G.; Gehrke, T.; Jakubek, J.; Gallas, R.; Berke, S.; Jäkel, O.; Mairani, A.; Ferrari, A.; Martišíková, M.

    2017-10-01

    Currently there is a rising interest in helium ion beams for radiotherapy. For benchmarking of the physical beam models used in treatment planning, there is a need for experimental data on the composition and spatial distribution of mixed ion fields. Of particular interest are the attenuation of the primary helium ion fluence and the build-up of secondary hydrogen ions due to nuclear interactions. The aim of this work was to provide such data with an enhanced precision. Moreover, the validity and limits of the mixed ion field equivalence between water and PMMA targets were investigated. Experiments with a 220.5 MeV/u helium ion pencil beam were performed at the Heidelberg Ion-Beam Therapy Center in Germany. The compact detection system used for ion tracking and identification was solely based on Timepix position-sensitive semiconductor detectors. In comparison to standard techniques, this system is two orders of magnitude smaller, and provides higher precision and flexibility. The numbers of outgoing helium and hydrogen ions per primary helium ion as well as the lateral particle distributions were quantitatively investigated in the forward direction behind water and PMMA targets with 5.2-18 cm water equivalent thickness (WET). Comparing water and PMMA targets with the same WET, we found that significant differences in the amount of outgoing helium and hydrogen ions and in the lateral particle distributions arise for target thicknesses above 10 cm WET. The experimental results concerning hydrogen ions emerging from the targets were reproduced reasonably well by Monte Carlo simulations using the FLUKA code. Concerning the amount of outgoing helium ions, significant differences of 3-15% were found between experiments and simulations. We conclude that if PMMA is used in place of water in dosimetry, differences in the dose distributions could arise close to the edges of the field, in particular for deep seated targets. The results presented in this publication are

  4. Ultrafast and directional diffusion of lithium in phosphorene for high-performance lithium-ion battery.

    Science.gov (United States)

    Li, Weifeng; Yang, Yanmei; Zhang, Gang; Zhang, Yong-Wei

    2015-03-11

    Density functional theory calculations have been performed to investigate the binding and diffusion behavior of Li in phosphorene. Our studies reveal the following findings: (1) Li atom forms strong binding with phosphorus atoms and exists in the cationic state; (2) the shallow energy barrier (0.08 eV) of Li diffusion on monolayer phosphorene along zigzag direction leads to an ultrahigh diffusivity, which is estimated to be 10(2) (10(4)) times faster than that on MoS2 (graphene) at room temperature; (3) the large energy barrier (0.68 eV) along armchair direction results in a nearly forbidden diffusion, and such strong diffusion anisotropy is absent in graphene and MoS2; (4) a remarkably large average voltage of 2.9 V is predicted in the phosphorene-based Li-ion battery; and (5) a semiconducting to metallic transition induced by Li intercalation of phosphorene gives rise to a good electrical conductivity, ideal for use as an electrode. Given these advantages, it is expected that phosphorene will present abundant opportunities for applications in novel electronic device and lithium-ion battery with a high rate capability and high charging voltage.

  5. Sol-gel coated ion sources for liquid chromatography-direct electron ionization mass spectrometry.

    Science.gov (United States)

    Riboni, Nicolò; Magrini, Laura; Bianchi, Federica; Careri, Maria; Cappiello, Achille

    2017-07-25

    Advances in interfacing liquid chromatography and electron ionization mass spectrometry are presented. New ion source coatings synthesized by sol-gel technology were developed and tested as vaporization surfaces in terms of peak intensity, peak width and peak delay for the liquid chromatography-direct electron ionization mass spectrometry (Direct-EI) determination of environmental pollutants like polycyclic aromatic hydrocarbons and steroids. Silica-, titania-, and zirconia-based coatings were sprayed inside the stainless steel ion source and characterized in terms of thermal stability, film thickness and morphology. Negligible weight losses until 350-400 °C were observed for all the materials, with coating thicknesses in the 6 (±1)-11 (±2) μm range for optimal ionization process. The best performances in terms of both peak intensity and peak width were obtained by using the silica-based coating: the detection of the investigated compounds was feasible at low ng μl -1 levels with a good precision (RSD < 9% for polycyclic aromatic hydrocarbons and <11% for hormones). Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Large area buried nanopatterning by broad ion implantation without any mask or direct writing

    OpenAIRE

    Karmakar, Prasanta; Satpati, Biswarup

    2013-01-01

    We have introduced here a simple, single step and cost effective broad ion beam technique for preparation of nanoscale electronic, magnetic, optical and mechanical devices without the need of resist, mask, or focused electron and ion beams. In this approach, broad beam ion implantation of desired atom on a prefabricated ion beam patterned surface promotes site selective deposition by adjusting the local angle of ion implantation. We show that implantation of Fe ions on an O+ induced pre fabri...

  7. Quantification of the Relative Biological Effectiveness for Ion Beam Radiotherapy: Direct Experimental Comparison of Proton and Carbon Ion Beams and a Novel Approach for Treatment Planning

    International Nuclear Information System (INIS)

    Elsaesser, Thilo; Weyrather, Wilma K.; Friedrich, Thomas; Durante, Marco; Iancu, Gheorghe; Kraemer, Michael; Kragl, Gabriele; Brons, Stephan; Winter, Marcus; Weber, Klaus-Josef; Scholz, Michael

    2010-01-01

    Purpose: To present the first direct experimental in vitro comparison of the biological effectiveness of range-equivalent protons and carbon ion beams for Chinese hamster ovary cells exposed in a three-dimensional phantom using a pencil beam scanning technique and to compare the experimental data with a novel biophysical model. Methods and Materials: Cell survival was measured in the phantom after irradiation with two opposing fields, thus mimicking the typical patient treatment scenario. The novel biophysical model represents a substantial extension of the local effect model, previously used for treatment planning in carbon ion therapy for more than 400 patients, and potentially can be used to predict effectiveness of all ion species relevant for radiotherapy. A key feature of the new approach is the more sophisticated consideration of spatially correlated damage induced by ion irradiation. Results: The experimental data obtained for Chinese hamster ovary cells clearly demonstrate that higher cell killing is achieved in the target region with carbon ions as compared with protons when the effects in the entrance channel are comparable. The model predictions demonstrate agreement with these experimental data and with data obtained with helium ions under similar conditions. Good agreement is also achieved with relative biological effectiveness values reported in the literature for other cell lines for monoenergetic proton, helium, and carbon ions. Conclusion: Both the experimental data and the new modeling approach are supportive of the advantages of carbon ions as compared with protons for treatment-like field configurations. Because the model predicts the effectiveness for several ion species with similar accuracy, it represents a powerful tool for further optimization and utilization of the potential of ion beams in tumor therapy.

  8. Ion Injections Inside Geosynchronous Orbit: Convection And Drift Dominated, Charge-Dependent Adiabatic Energization (W = qEd)

    Science.gov (United States)

    Mitchell, D. G.; Gkioulidou, M.; Ukhorskiy, S.

    2017-12-01

    Particle injection, a major mode of plasma transport and energization throughout the magnetosphere, has been studied for decades. Nonetheless, the physical processes that lead to the acceleration of ions in the inner magnetosphere during injection events is still under debate. In this paper, we analyze several injection events occurring near the Van Allen Probes apogee. Our analysis shows that the upper energy of an injected ion depends on the charge-state of that ion. In that regard, most of the helium injected is doubly ionized (He++), while oxygen charge states are consistent with the presence of both ionospheric (O+) and solar wind (O6+) source populations. Based on the findings of our data analysis and with the use of a simple model, we demonstrate that the behavior of injections of energetic ions near the Van Allen Probes apogee (5 < L < 7 RE) is well explained by simple transport within flow channels from higher L (≥10 RE) with velocities at 10 RE ranging between 200 and 2000km/s and falling with inward transport consistent with fixed potential drops across the flow channels. Gradient/curvature drift during transport limits the highest energy/charge observed at the Van Allen Probes. Energization depends on charge state, but is independent of ion mass.

  9. Direct processes in ion-atom collisions at intermediate and high energies

    International Nuclear Information System (INIS)

    Rodriguez Chariarse, V.D.

    1990-01-01

    This thesis deals with direct processes induced by Zp charge ion impact on one or two electron atoms and ions at intermediate energies. At a first step, a one-dimensional collision model is used in order to prove the different theoretical methods available to study collisions at such energy range, such as: perturbative and related variational principles, and distorted wave methods. The best description of both, symmetric and asymmetric collision type, is achieved by the distorted wave methods, particularly the ones using the exact impulsive wave function. As a next step, the appropriate formulations of the wave functions employed in the one-dimensional model to describe the real 3-dimensional Coulomb interaction case are examined by using the Eikonal and impulse hypothesis. In this way, the VPS and Eikonal wave functions are reviewed, and furtherly, the Eikonal form of the extended impulse wave function is derived. The Eikonal impulse approximation (EIA) is introduced. This is a distorted wave method using the Eikonal and extended impulse wave functions. The choice of the EIA prior version, i.e., the one using extended impulse wave function in the final channel for excitation is widely discussed and justified. (Author) [es

  10. Direct evidence for a thermal effect of Ar+ ion bombardment in a conventional sputtering mode

    International Nuclear Information System (INIS)

    Okuyama, F.; Fujimoto, Y.

    1986-01-01

    Evidence is presented that the Ar + ion bombardment for sputtering in Auger electron spectroscopy can heat the target up to 2000 0 C if the target has poor heat conduction. Polycrystalline microneedles of Cr exhibited spherical tips after being exposed to 3 keV Ar + ions, proving that the needle tips were melted by impacting Ar + ions. Microneedles of Mo ion bombarded under the same condition were bent plastically, which perhaps reflects the thermal annealing of the needles during ion bombardment

  11. Preferred Spatial Directions in the Universe. Part II. Matter Distributed along Orbital Trajectories, and Energy Produced from It

    Directory of Open Access Journals (Sweden)

    Borissova L.

    2006-10-01

    Full Text Available Using General Relativity we study the rotating space of an orbiting body (of the Earth in the Galaxy, for example. In such a space Einstein’s equations predict that: (1 the space cannot be empty; (2 it abhors a vacuum (i. e. a pure λ-field, and so it must also possess a substantive distribution (e. g. gas, dust, radiations, etc.. In order for Maxwell’s equations to satisfy Einstein’s equations, it is shown that: (1 a free electromagnetic field along the trajectory of an orbiting body must be present, by means of purely magnetic “standing” waves; (2 electromagnetic fields don’t satisfy the Einstein equations in a region of orbiting space bodies if there is no distribution of another substance (e. g. dust, gas or something else. The braking energy of a medium pervading space equals the energy of the space non-holonomic field. The energy transforms into heat and radiations within stars by a stellar energy mechanism due to the background space non-holonomity, so a star takes energy for luminosity from the space during the orbit. Employing this mechanism in an Earth-bound laboratory, we can obtain a new source of energy due to the fact that the Earth orbits in the non-holonomic fields of the space.

  12. Comparisons between direct ion storage and thermoluminescence dosimetry individual monitoring systems, and internet reporting

    International Nuclear Information System (INIS)

    Kiuru, A.; Kahilainen, J.; Hyvoenen, H.; Vartiainen, E.

    2001-01-01

    A new electronic direct ion storage (DIS) dosemeter allows accumulated personal dose equivalent H p (d) at depths of 10 mm and 0.07 mm to be monitored in a few seconds by inserting the dosemeter into a local reader without deleting the accumulated dose. The DIS system meets general requirements on individual monitoring of hospital personnel using ionising radiation. It differs greatly from off-line thermoluminescence dosimetry systems and offers many additional benefits. The non-volatile reading takes only 5 s, is taken as often as needed, and the data are collected into a dose database, where background radiation is subtracted. Individual personnel doses are reported in Intranet as well as on the Internet at regular intervals to the National Regulatory Authorities. (author)

  13. Immobilized metal ion affinity hollow-fibre membranes obtained by the direct grafting technique

    Science.gov (United States)

    Grasselli, Mariano; Navarro del Cañizo, Agustín. A.; Camperi, Silvia A.; Wolman, Federico J.; Smolko, Eduardo E.; Cascone, Osvaldo

    1999-06-01

    An immobilized metal ion affinity hollow fibre was prepared by radiation-induced direct grafting of glycidylmethacrylate (GMA) on hydrophilized polyethylene membranes. The epoxy group was converted into an iminodiacetate by iminodiacetic acid treatment. The effect of the radiation dose, salt inhibitors, methanol and GMA concentration, on the grafting degree was studied. The degree of grafting was closely related to the GMA concentration. Salt inhibitors failed in the production of a differential effect on the grafting and homopolymerization processes. Between 30 and 35% of methanol, there is a maximum yield, and no grafting was obtained with a methanol concentration above 50%. Water flux dropped exponentially with the increase in the grafting degree. Scanning-electron microscopy showed that the graft branches are formed on the pores. The pectinesterase adsorption capacity of the membranes was of the same order as of the commercial chelating soft gels.

  14. Multi-mycotoxin Analysis of Finished Grain and Nut Products Using Ultrahigh-Performance Liquid Chromatography and Positive Electrospray Ionization-Quadrupole Orbital Ion Trap High-Resolution Mass Spectrometry.

    Science.gov (United States)

    Liao, Chia-Ding; Wong, Jon W; Zhang, Kai; Yang, Paul; Wittenberg, James B; Trucksess, Mary W; Hayward, Douglas G; Lee, Nathaniel S; Chang, James S

    2015-09-23

    Ultrahigh-performance liquid chromatography using positive electrospray ionization and quadrupole orbital ion trap high-resolution mass spectrometry was evaluated for analyzing mycotoxins in finished cereal and nut products. Optimizing the orbital ion trap mass analyzer in full-scan mode using mycotoxin-fortified matrix extracts gave mass accuracies, δM, of aflatoxin B1 in peanut and almond) to 1175 μg/kg (fumonisin B1 in corn flour) were found in 35 of the 70 commercial grain and nut samples surveyed. Mycotoxins could be identified at δM nut products.

  15. Direct separation of 67Ga citrate from zinc and copper target materials by an ion exchange

    International Nuclear Information System (INIS)

    El-Azony, K.M.; Ferieg, Kh.; Saleh, Z.A.

    2004-01-01

    The separation of 6 7G a from zinc and copper target materials using an anion- f:exchanger (Dowex21K) and 0.1 M citrate buffer at pH 6 is described. The gallium-67 was separated in citrate solution and can be directly used for medical applications. Gallium-67 with a half-life of 78.3 h and gamma-rays with energies of 93, 185 and 300 keV is a cyclotron produced radioisotope for which a considerable demand exists. 6 7G a is frequently produced through proton or deuteron bombardment of natural or enriched Zn targets (Helus and Maier-Borst, 1973). It is usually separated from Zn by ion exchange chromatography (Helus and Maier-Borst, 1973; van der Walt and Strelow, 1983) or by liquid extraction Helus and Maier-Borst, 1973; Hupf and Beaver, 1970). The isotope is usually supplied in citrate solution which is widely used as 6 7G a Gallium citrate which is a well-established radiopharmaceutical for imaging soft tissue tumors and abscesses. Several routes for large scale production of 6 7G a and the development of medical applications have been reported (Silvester and Thakur, 1970; Dahl and Tilbury, 1972; Steyn and Meyer,1973; Vlatkovic et al., 1975; Neirinckx, 1976; Thakur, 1977). Various attempts were carried out to separate gallium-67 by using different ion exchange methods (Strelow et al., 1971; Das and Ramamoorthy, 1995; Boothe et al.,1991) through the labelling of citrate by using 6 7G a was carried out for medical applications

  16. Direction for the Future - Successive Acceleration of Positive and Negative Ions Applied to Space Propulsion

    CERN Document Server

    Aanesland, A.; Popelier, L.; Chabert, P.

    2013-12-16

    Electrical space thrusters show important advantages for applications in outer space compared to chemical thrusters, as they allow a longer mission lifetime with lower weight and propellant consumption. Mature technologies on the market today accelerate positive ions to generate thrust. The ion beam is neutralized by electrons downstream, and this need for an additional neutralization system has some drawbacks related to stability, lifetime and total weight and power consumption. Many new concepts, to get rid of the neutralizer, have been proposed, and the PEGASES ion-ion thruster is one of them. This new thruster concept aims at accelerating both positive and negative ions to generate thrust, such that additional neutralization is redundant. This chapter gives an overview of the concept of electric propulsion and the state of the development of this new ion-ion thruster.

  17. Ion adsorption and its influence on direct current electric field induced deformations of flexoelectric nematic layers.

    Science.gov (United States)

    Derfel, Grzegorz; Buczkowska, Mariola

    2011-07-07

    The influence of ion adsorption on the behavior of the nematic liquid crystal layers is studied numerically. The homeotropic flexoelectric layer subjected to the dc electric field is considered. Selective adsorption of positive ions is assumed. The analysis is based on the free energy formalism for ion adsorption. The distributions of director orientation angle, electric potential, and ion concentrations are calculated by numerical resolving of suitable torques equations and Poisson equation. The threshold voltages for the deformations are also determined. It was shown that adsorption affects the distributions of both cations and anions. Sufficiently large number of adsorbed ions leads to spontaneous deformation arising without any threshold if the total number of ions creates sufficiently strong electric field with significant field gradients in the neighborhood of electrodes. The spontaneous deformations are favored by strong flexoelectricity, large thickness, large ion concentrations, weak anchoring, and large adsorption energy.

  18. Direct determination of recoil ion detection efficiency for coincidence time-of-flight studies of molecular fragmentation

    Science.gov (United States)

    Ben-Itzhak, I.; Carnes, K. D.; Ginther, S. G.; Johnson, D. T.; Norris, P. J.; Weaver, O. L.

    1993-06-01

    Molecular fragmentation of diatomic and small polyatomic molecules caused by fast ion impact has been studied. The evaluation of the cross sections of the different fragmentation channels depends strongly on the recoil ion detection efficiency, ɛ r (single ions proportional to ɛ r, and ion pairs to ɛ r2, etc.). A method is suggested for the direct determination of this detection efficiency. This method is based on the fact that fast H + + CH 4 collisions produce C 2+ fragments only in coincidence with H + and H +2 fragments, that is, there is a negligible number of C 2+ singles, if any. The measured yield of C 2+ singles is therefore due to events in which the H +m of the H +m +C 2+ ion pair was not detected and thus is proportional to 1-ɛ r. Methane fragmentation caused by 1 MeV proton impact is used to evaluate directly the recoil ion detection efficiency and to demonstrate the method of deriving the cross sections of all breakup channels.

  19. Directly measuring mean and variance of infinite-spectrum observables such as the photon orbital angular momentum.

    Science.gov (United States)

    Piccirillo, Bruno; Slussarenko, Sergei; Marrucci, Lorenzo; Santamato, Enrico

    2015-10-19

    The standard method for experimentally determining the probability distribution of an observable in quantum mechanics is the measurement of the observable spectrum. However, for infinite-dimensional degrees of freedom, this approach would require ideally infinite or, more realistically, a very large number of measurements. Here we consider an alternative method which can yield the mean and variance of an observable of an infinite-dimensional system by measuring only a two-dimensional pointer weakly coupled with the system. In our demonstrative implementation, we determine both the mean and the variance of the orbital angular momentum of a light beam without acquiring the entire spectrum, but measuring the Stokes parameters of the optical polarization (acting as pointer), after the beam has suffered a suitable spin-orbit weak interaction. This example can provide a paradigm for a new class of useful weak quantum measurements.

  20. Humidity affects relative ion abundance in direct analysis in real time mass spectrometry of hexamethylene triperoxide diamine.

    Science.gov (United States)

    Newsome, G Asher; Ackerman, Luke K; Johnson, Kevin J

    2014-12-16

    Unstable explosive hexamethylene triperoxide diamine (HMTD) is dangerous in quantity and benefits from the minimal sampling handling associated with atmospheric pressure chemical ionization for mass spectral analysis. Seasonal variation observed in HMTD mass spectra suggested a humidity dependence. Therefore, direct analysis in real time (DART) ionization mass spectra were acquired at a range of humidity values. An enclosure was designed to fit around the ion source and mass spectrometer inlet at atmospheric pressure. The enclosure was supplied with controlled amounts of humidified air from a test atmosphere generator to create programmable conditions for ambient analysis. The relative abundance and fragmentation of analyte ions were observed to change reliably with changing humidity values and, to a lesser degree, temperature. Humidity at such plasma-based ion sources should be regulated to avoid ∼90% shifts in relative ion abundance and provide stability and reproducibility of HMTD analysis.

  1. Bioelectrochemical systems-driven directional ion transport enables low-energy water desalination, pollutant removal, and resource recovery.

    Science.gov (United States)

    Chen, Xi; Liang, Peng; Zhang, Xiaoyuan; Huang, Xia

    2016-09-01

    Bioelectrochemical systems (BESs) are integrated water treatment technologies that generate electricity using organic matter in wastewater. In situ use of bioelectricity can direct the migration of ionic substances in a BES, thereby enabling water desalination, resource recovery, and valuable substance production. Recently, much attention has been placed on the microbial desalination cells in BESs to drive water desalination, and various configurations have optimized electricity generation and desalination performance and also coupled hydrogen production, heavy metal reduction, and other reactions. In addition, directional transport of other types of charged ions can remediate polluted groundwater, recover nutrient, and produce valuable substances. To better promote the practical application, the use of BESs as directional drivers of ionic substances requires further optimization to improve energy use efficiency and treatment efficacy. This article reviews existing researches on BES-driven directional ion transport to treat wastewater and identifies a few key factors involved in efficiency optimization. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Pitx2, an atrial fibrillation predisposition gene, directly regulates ion transport and intercalated disc genes.

    Science.gov (United States)

    Tao, Ye; Zhang, Min; Li, Lele; Bai, Yan; Zhou, Yuefang; Moon, Anne M; Kaminski, Henry J; Martin, James F

    2014-02-01

    Pitx2 is the homeobox gene located in proximity to the human 4q25 familial atrial fibrillation (AF) locus. When deleted in the mouse germline, Pitx2 haploinsufficiency predisposes to pacing-induced AF, indicating that reduced Pitx2 promotes an arrhythmogenic substrate. Previous work focused on Pitx2 developmental functions that predispose to AF. Although Pitx2 is expressed in postnatal left atrium, it is unknown whether Pitx2 has distinct postnatal and developmental functions. To investigate Pitx2 postnatal function, we conditionally inactivated Pitx2 in the postnatal atrium while leaving its developmental function intact. Unstressed adult Pitx2 homozygous mutant mice display variable R-R interval with diminished P-wave amplitude characteristic of sinus node dysfunction, an AF risk factor in human patients. An integrated genomics approach in the adult heart revealed Pitx2 target genes encoding cell junction proteins, ion channels, and critical transcriptional regulators. Importantly, many Pitx2 target genes have been implicated in human AF by genome-wide association studies. Immunofluorescence and transmission electron microscopy studies in adult Pitx2 mutant mice revealed structural remodeling of the intercalated disc characteristic of human patients with AF. Our findings, revealing that Pitx2 has genetically separable postnatal and developmental functions, unveil direct Pitx2 target genes that include channel and calcium handling genes, as well as genes that stabilize the intercalated disc in postnatal atrium.

  3. Directed Flow in Heavy-Ion Collisions and Its Implications for Astrophysics

    Directory of Open Access Journals (Sweden)

    Yuri B. Ivanov

    2017-11-01

    Full Text Available Analysis of directed flow ( v 1 of protons, antiprotons and pions in heavy-ion collisions is performed in the range of collision energies s N N = 2.7–39 GeV. Simulations have been done within a three-fluid model employing a purely hadronic equation of state (EoS and two versions of the EoS with deconfinement transitions: a first-order phase transition and a smooth crossover transition. The crossover EoS is unambiguously preferable for the description of experimental data at lower collision energies s N N ≲ 20 Gev. However, at higher collision energies s N N ≳ 20 Gev. the purely hadronic EoS again becomes advantageous. This indicates that the deconfinement EoS in the quark-gluon sector should be stiffer at high baryon densities than those used in the calculation. The latter finding is in agreement with that discussed in astrophysics in connection with existence of hybrid stars with masses up to about two solar masses.

  4. Direct trace analysis of metals and alloys in a quadrupole ion-trap mass spectrometer

    CERN Document Server

    Song, K S; Yang, M; Cha, H K; Lee, J M; Lee, G H

    1999-01-01

    An ion-trap mass spectrometer adopting a quadrupole ion-trap and laser ablation/ionization method was constructed. The developed system was tested for composition analysis of some metals (Cu, stainless), and alloys (hastalloy C, mumetal) by mass spectrometry. Samples were analyzed by using laser ablation from a sample probe tip followed by a mass analysis with the quadrupole ion-trap. The quadrupole ion-trap was modified to enable laser ablation by a XeCl excimer laser pulse that passed radially through the ring electrode. A mass scan of the produced ions was performed in the mass selective instability mode wherein trapped ions were successively detected by increasing the rf voltage through the ring electrode. Factors affecting the mass resolution, such as pressure of buffer gas and ablation laser power, are discussed.

  5. ions

    African Journals Online (AJOL)

    (MP2 B2). In order to draw the final conclusion about the content of the isomers of pentaatomic ions in saturated vapor over cesium chloride, we have taken into account the entropy factor. We considered the isomerization reactions which are given below: Cs3Cl2. + (V-shaped) = Cs3Cl2. + (cyclic or bipyramidal). (1). Cs2Cl3.

  6. Miniature focal plane mass spectrometer with 1000-pixel modified-CCD detector array for direct ion measurement

    Science.gov (United States)

    Sinha, Mahadeva P.; Wadsworth, Mark

    2005-02-01

    A high performance, focal plane miniature mass spectrometer (MMS) of Mattauch-Herzog geometry with a CCD-based array detector for the direct and simultaneous measurements of different mass ions is described. Miniaturization (10cm×5cm×5cm,395g) was accomplished by using high-energy-product magnet material (Nd-B-Fe alloy) and a high permeability yoke material (V-Co-Fe Alloy) for the fabrication of the magnetic sector. The electrostatic sector was machined from a single piece of machinable ceramic (MACOR). All the components of the analyzer are mounted on a single plate, which facilitate their alignment and make the instrument rugged. The modified-CCD based ion detector array has 1000 elements (20μm×2mm) and was invented in our laboratory. The photosensitive part of the CCD was replaced with a metal-oxide-semiconductor (MOS) capacitor for ion detection. The ion sensing capacitor plates are connected to the CCD gates that are operated in the fill-and spill mode providing a gain in the charge domain for the signal ions and minimizing various noises during measurements. The results reported in this article are the first application of this detector array for direct ion measurement and successfully prove the new technology. The MMS with the array detector can measure masses up to 250u with a unit mass resolution and expected to possess a sensitivity of detecting ˜5ions. The above attributes make MMS suitable for space applications for isotopic and chemical analysis and also for field applications on earth.

  7. High-resolution direct-write patterning using focused ion beams

    NARCIS (Netherlands)

    Ocola, L.E.; Rue, C.; Maas, D.J.

    2014-01-01

    Over the last few years, significant improvements in sources, columns, detectors, control software, and accessories have enabled a wealth of new focused ion beam applications. In addition, modeling has provided many insights into ion-sample interactions and the resultant effects on the sample. With

  8. Direct observation of the point-defect structure of depleted-zones in ion-irradiated metals

    Energy Technology Data Exchange (ETDEWEB)

    Wei, C.

    1978-01-01

    The point-defect structure of individual depleted zones has been studied systematically. Four-pass zone-refined tungsten field-ion microscope (FIM) specimens were irradiated in-situ at 10 K with 30 keV Cr/sup +/, Mo/sup +/, or W/sup +/ ions to a total dose of (2 to 10) x 10/sup 12/ ion cm/sup -2/ and examined by the pulse field-evaporation technique at 10 K. The experimental conditions were such that each depleted zone was created by a single incident-ion. The number of vacant lattice sites within a depleted zone was compared with a modified Kinchin--Pease model. The radial distribution function was determined for each depleted zone; it was found that the vacant lattice sites within the volume of each depleted zone tended to exist in a highly clustered state. It was found that the diameter D of each depleted zone was described by the equation D approximately equal to (y/sup 2/)/sup /sup 1///sub 2// where (y/sup 2/)/sup /sup 1///sub 2// is the second moment of the theoretical distribution curve, of the fraction of incident ion energy deposited in atom motion, transverse to the direction of the incident ion-beam. The spatial distribution of self-interstitial atoms (SIAs) in a specimen irradiated with 30 keV Cr/sup +/ ions and in a specimen irradiated with 18 keV Au/sup +/ ions, at 10 K, was determined. A low bound to the average range of replacement collision sequences (RCSs) was found to be 175 +- 85 A. A detailed FIM study was also made of the vacancy structure of a (220) platelet created by a single 30 keV W/sup +/ ion in a platinum-4.0 at. % gold alloy; the specimen was irradiated at 40 K and then isochronally warmed to 100 K. The (220) platelet was found to consist of 31 vacant lattice sites, lying in four (220) planes, and clustered in a disc-shaped region which is approximately 20 A in diameter. It was suggested that prismatic dislocation loops lying on (220) type planes in ion or fast neutron irradiated platinum can form as a result of the direct collapse of

  9. Nanodosimetric Simulation of Direct Ion-Induced DNA Damage Using Different Chromatin Geometry Models.

    Science.gov (United States)

    Henthorn, N T; Warmenhoven, J W; Sotiropoulos, M; Mackay, R I; Kirkby, K J; Merchant, M J

    2017-12-01

    Monte Carlo based simulation has proven useful in investigating the effect of proton-induced DNA damage and the processes through which this damage occurs. Clustering of ionizations within a small volume can be related to DNA damage through the principles of nanodosimetry. For simulation, it is standard to construct a small volume of water and determine spatial clusters. More recently, realistic DNA geometries have been used, tracking energy depositions within DNA backbone volumes. Traditionally a chromatin fiber is built within the simulation and identically replicated throughout a cell nucleus, representing the cell in interphase. However, the in vivo geometry of the chromatin fiber is still unknown within the literature, with many proposed models. In this work, the Geant4-DNA toolkit was used to build three chromatin models: the solenoid, zig-zag and cross-linked geometries. All fibers were built to the same chromatin density of 4.2 nucleosomes/11 nm. The fibers were then irradiated with protons (LET 5-80 keV/μm) or alpha particles (LET 63-226 keV/μm). Nanodosimetric parameters were scored for each fiber after each LET and used as a comparator among the models. Statistically significant differences were observed in the double-strand break backbone size distributions among the models, although nonsignificant differences were noted among the nanodosimetric parameters. From the data presented in this article, we conclude that selection of the solenoid, zig-zag or cross-linked chromatin model does not significantly affect the calculated nanodosimetric parameters. This allows for a simulation-based cell model to make use of any of these chromatin models for the scoring of direct ion-induced DNA damage.

  10. Direct probing of ion pair formation using a symmetric triangulenium dye.

    Science.gov (United States)

    Westerlund, Fredrik; Elm, Jonas; Lykkebo, Jacob; Carlsson, Nils; Thyrhaug, Erling; Akerman, Björn; Sørensen, Thomas Just; Mikkelsen, Kurt V; Laursen, Bo W

    2011-12-01

    The 2,6,10-tris(dialkylamino)trioxatriangulenium dyes (ATOTA(+)) are highly stabilised cationic chromophores with D(3h) symmetry. The symmetry gives rise to a degeneracy of the main electronic transition. In low polarity solvents significant splitting of this degenerate transition is observed and assigned to ion pair formation. Ion pairing of the 2,6,10-tris(dioctylamino)trioxatriangulenium ion with Cl(-), BF(4)(-), PF(6)(-) and TRISPHAT anions was studied using absorption spectroscopy. A clear correlation is found between the size of the anion and the splitting of the ATOTA(+) transitions. In benzene the Cl(-) salt displays a splitting of 1955 cm(-1), while the salt of the much larger TRISPHAT ion has a splitting of 1543 cm(-1). TD-DFT calculations confirm the splitting of the states and provide a detailed insight into the electronic structure of the ion pairs. The different degree of splitting in different ion pairs is found to correlate with the magnitude of the electric field generated in each ion pair, thus leading to the conclusion that the effect seen is an internal Stark effect. By insertion of an amphiphilic derivative of the ATOTA(+) chromophore in an oriented lamellar liquid crystal, it was possible to resolve the two bands of the double peak spectrum and show their perpendicular orientation in the molecular framework, as predicted by the calculations.

  11. Seeking structural specificity: direct modulation of pentameric ligand-gated ion channels by alcohols and general anesthetics.

    Science.gov (United States)

    Howard, Rebecca J; Trudell, James R; Harris, R Adron

    2014-01-01

    Alcohols and other anesthetic agents dramatically alter neurologic function in a wide range of organisms, yet their molecular sites of action remain poorly characterized. Pentameric ligand-gated ion channels, long implicated in important direct effects of alcohol and anesthetic binding, have recently been illuminated in renewed detail thanks to the determination of atomic-resolution structures of several family members from lower organisms. These structures provide valuable models for understanding and developing anesthetic agents and for allosteric modulation in general. This review surveys progress in this field from function to structure and back again, outlining early evidence for relevant modulation of pentameric ligand-gated ion channels and the development of early structural models for ion channel function and modulation. We highlight insights and challenges provided by recent crystal structures and resulting simulations, as well as opportunities for translation of these newly detailed models back to behavior and therapy.

  12. Direct Visualization of Solid Electrolyte Interphase Formation in Lithium-Ion Batteries with In Situ Electrochemical Transmission Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Unocic, Raymond R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sun, Xiao-Guang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sacci, Robert L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Adamczyk, Leslie A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Alsem, Daan Hein [Hummingbird Scientific, Lacey, WA (United States); Dai, Sheng [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dudney, Nancy J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); More, Karren Leslie [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-08-01

    Complex, electrochemically driven transport processes form the basis of electrochemical energy storage devices. The direct imaging of electrochemical processes at high spatial resolution and within their native liquid electrolyte would significantly enhance our understanding of device functionality, but has remained elusive. In this work we use a recently developed liquid cell for in situ electrochemical transmission electron microscopy to obtain insight into the electrolyte decomposition mechanisms and kinetics in lithium-ion (Li-ion) batteries by characterizing the dynamics of solid electrolyte interphase (SEI) formation and evolution. Here we are able to visualize the detailed structure of the SEI that forms locally at the electrode/electrolyte interface during lithium intercalation into natural graphite from an organic Li-ion battery electrolyte. We quantify the SEI growth kinetics and observe the dynamic self-healing nature of the SEI with changes in cell potential.

  13. Orbit analysis

    International Nuclear Information System (INIS)

    Michelotti, L.

    1995-01-01

    The past fifteen years have witnessed a remarkable development of methods for analyzing single particle orbit dynamics in accelerators. Unlike their more classic counterparts, which act upon differential equations, these methods proceed by manipulating Poincare maps directly. This attribute makes them well matched for studying accelerators whose physics is most naturally modelled in terms of maps, an observation that has been championed most vigorously by Forest. In the following sections the author sketchs a little background, explains some of the physics underlying these techniques, and discusses the best computing strategy for implementing them in conjunction with modeling accelerators

  14. Orbit analysis

    Energy Technology Data Exchange (ETDEWEB)

    Michelotti, L.

    1995-01-01

    The past fifteen years have witnessed a remarkable development of methods for analyzing single particle orbit dynamics in accelerators. Unlike their more classic counterparts, which act upon differential equations, these methods proceed by manipulating Poincare maps directly. This attribute makes them well matched for studying accelerators whose physics is most naturally modelled in terms of maps, an observation that has been championed most vigorously by Forest. In the following sections the author sketchs a little background, explains some of the physics underlying these techniques, and discusses the best computing strategy for implementing them in conjunction with modeling accelerators.

  15. Correlation between structural and magnetic properties of half-metallic spinel CuV2S4 due to the order-disorder transition of 3d2(t2g) orbitals of V3+ ions

    International Nuclear Information System (INIS)

    Kumara, L.S.R.; Tokiwa, N.; Awaka, J.; Hagino, T.; Nagata, S.; Park, Young Jun; Hidaka, M.

    2008-01-01

    Structural and magnetic properties of the spinel CuV 2 S 4 have been studied by means of X-ray diffraction using synchrotron radiation and measurements of magnetic susceptibility. The structural phase transitions occur at about 55 K and 90 K, and the superlattice reflections (h±q o , k±q o , l) having an orthorhombic reduced wavevector q o =(1/4,1/4,0) are observed at 10 K. This suggests that the structure below 55 K is a commensurate unit cell of 4a p x 4b p x c p , where the subscript 'p' means a pseudo-spinel structure, and that the structural phase transitions are induced by the cooperative displacement of S ions in one-dimensional VS 6 octahedral chains, which are aligned along an orthorhombic[110] direction. The susceptibility also shows that the weak ferromagnetic transition occurs at about 90 K, and the spike-like susceptibility is observed in the region of about 40 K and 55 K. The unusual electronic and magnetic properties of CuV 2 S 4 in the low-temperature phases below about 90 K are interpreted by order and disorder states of (3d xy , 3d yz , 3d zx ) for the V 3+ 3d 2 (t 2g ) orbitals in the VS 6 octahedral chains. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Large orbit neoclassical transport

    International Nuclear Information System (INIS)

    Lin, Z.; Tang, W.M.; Lee, W.W.

    1997-01-01

    Neoclassical transport in the presence of large ion orbits is investigated. The study is motivated by the recent experimental results that ion thermal transport levels in enhanced confinement tokamak plasmas fall below the open-quotes irreducible minimum levelclose quotes predicted by standard neoclassical theory. This apparent contradiction is resolved in the present analysis by relaxing the basic neoclassical assumption that the ions orbital excursions are much smaller than the local toroidal minor radius and the equilibrium scale lengths of the system. Analytical and simulation results are in agreement with trends from experiments. The development of a general formalism for neoclassical transport theory with finite orbit width is also discussed. copyright 1997 American Institute of Physics

  17. Directions for reactor target design based on the US heavy ion fusion systems assessment

    International Nuclear Information System (INIS)

    Wilson, D.C.; Dudziak, D.; Magelssen, G.; Zuckerman, D.; Dreimeyer, D.

    1986-01-01

    We studied areas of major uncertainty in target design using the cost of electricity as our figure of merit. Net electric power from the plant was fixed at 1000 MW to eliminate large effects due to economies of scale. The system is relatively insensitive to target gain. Factors of three changes in gain cause only 8 to 12% changes in electricity cost. An increase in the peak power needed to drive targets poses only a small cost risk, but requires many more beamlets be transported to the target. A shortening of the required ion range causes both cost and beamlet difficulties. A factor of 4 decrease in the required range at a fixed driver energy increases electricity cost by 44% and raises the number of beamlets to 240. Finally, the heavy ion fusion system can accommodate large increases in target costs. To address the major uncertainties, target design should concentrate on the understanding requirements for ion range and peak driver power

  18. Feasibility of corona discharge ion mobility spectrometry for direct analysis of samples extracted by dispersive liquid-liquid microextraction.

    Science.gov (United States)

    Jafari, Mohammad T; Riahi, Farhad

    2014-05-23

    The capability of corona discharge ionization ion mobility spectrometry (CD-IMS) for direct analysis of the samples extracted by dispersive liquid-liquid microextraction (DLLME) was investigated and evaluated, for the first time. To that end, an appropriate new injection port was designed and constructed, resulting in possibility of direct injection of the known sample volume, without tedious sample preparation steps (e.g. derivatization, solvent evaporation, and re-solving in another solvent…). Malathion as a test compound was extracted from different matrices by a rapid and convenient DLLME method. The positive ion mobility spectra of the extracted malathion were obtained after direct injection of carbon tetrachloride or methanol solutions. The analyte responses were compared and the statistical results revealed the feasibility of direct analysis of the extracted samples in carbon tetrachloride, resulting in a convenient methodology. The coupled method of DLLME-CD-IMS was exhaustively validated in terms of sensitivity, dynamic range, recovery, and enrichment factor. Finally, various real samples of apple, river and underground water were analyzed, all verifying the feasibility and success of the proposed method for the easy extraction of the analyte using DLLME separation before the direct analysis by CD-IMS. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Microwave plasma torch mass spectrometry for the direct detection of copper and molybdenum ions in aqueous liquids.

    Science.gov (United States)

    Xiong, Xiaohong; Jiang, Tao; Zhou, Runzhi; Wang, Shangxian; Zou, Wei; Zhu, Zhiqiang

    2016-05-01

    Microwave plasma torch (MPT) is a simple and low power-consumption ambient ion source. And the MPT Mass spectra of many metal elements usually exhibit some novel features different from their inductively coupled plasma (ICP) mass spectra, which may be helpful for metal element analysis. Here, we presented the results about the MPT mass spectra of copper and molybdenum elements by a linear ion trap mass spectrometer (LTQ). The generated copper or molybdenum contained ions in plasma were characterized further in collision-induced dissociated (CID) experiments. These researches built a novel, direct and sensitive method for the direct analysis of trace levels of copper and molybdenum in aqueous liquids. Quantitative results showed that the limit of detection (LOD) by using MS(2) procedure was estimated to be 0.265 µg/l (ppb) for copper and 0.497 µg/l for molybdenum. The linear dynamics ranges cover at least 2 orders of magnitude and the analysis of a single aqueous sample can be completed in 5-6 min with a reasonable semi-quantitative sense. Two practical aqueous samples, milk and urine, were also analyzed qualitatively with reasonable recovery rates and RSD. These experimental data demonstrated that the MPT MS is able to turn into a promising and hopeful tool in field analysis of copper and molybdenum ions in water and some aqueous media, and can be applied in many fields, such as environmental controlling, hydrogeology, and water quality inspection. Moreover, MPT MS could also be used as the supplement of ICP-MS for the rapid and in-situ analysis of metal ions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  20. Deadly Sunflower Orbits

    Science.gov (United States)

    Hamilton, Douglas P.

    2018-04-01

    Solar radiation pressure is usually very effective at removing hazardous millimeter-sized debris from distant orbits around asteroidsand other small solar system bodies (Hamilton and Burns 1992). Theprimary loss mechanism, driven by the azimuthal component of radiationpressure, is eccentricity growth followed by a forced collision withthe central body. One large class of orbits, however, neatly sidestepsthis fate. Orbits oriented nearly perpendicular to the solar directioncan maintain their face-on geometry, oscillating slowly around a stableequilibrium orbit. These orbits, designated sunflower orbits, arerelated to terminator orbits studied by spacecraft mission designers(Broschart etal. 2014).Destabilization of sunflower orbits occurs only for particles smallenough that radiation pressure is some tens of percent the strength ofthe central body's direct gravity. This greatly enhanced stability,which follows from the inability of radiation incident normal to theorbit to efficiently drive eccentricities, presents a threat tospacecraft missions, as numerous dangerous projectiles are potentiallyretained in orbit. We have investigated sunflower orbits insupport of the New Horizons, Aida, and Lucy missions and find thatthese orbits are stable for hazardous particle sizes at asteroids,comets, and Kuiper belt objects of differing dimensions. Weinvestigate the sources and sinks for debris that might populate suchorbits, estimate timescales and equilibrium populations, and willreport on our findings.

  1. Study of Negative-Ion TPC Using μ-PIC for Directional Dark Matter Search

    Science.gov (United States)

    Ikeda, Tomonori; Miuch, Kentaro; Ochi, Atsuhiko; Yakabe, Ryota; Hashimoto, Takashi; Taishaku, Ryosuke; Snowden-Ifft, Daniel P.; Gauvreau, Jean-Luc; Tanimori, Toru; Takada, Atsushi; Nakamura, Kiseki

    2018-02-01

    Negative-ion time projection chambers(TPCs) have been studied for low-rate and high-resolution applications such as dark matter search experiments. Recently, a full volume fiducialization in a self-triggering TPC was realized. This innovative technology demonstrated a significant reduction in the background with MWPC-TPCs. We studied negative-ion TPC using the μ-PIC+GEM system and obtained sufficient gas gain with CS2 gas and SF6 gas at low pressures. We expect an improvement in detector sensitivity and angular resolution with better electronics.

  2. Direct Imaging of a Cold Jovian Exoplanet in Orbit around the Sun-Like Star GJ 504

    Science.gov (United States)

    Kuzuhara, M.; Tamura, M.; Kudo, T.; Janson, M; Kandori, R.; Brandt, T. D.; Thalmann, C.; Spiegel, D.; Biller, B.; Carson, J.; hide

    2013-01-01

    Several exoplanets have recently been imaged at wide separations of >10 AU from their parent stars. These span a limited range of ages ( 0.5 mag), implying thick cloud covers. Furthermore, substantial model uncertainties exist at these young ages due to the unknown initial conditions at formation, which can lead to an order of magnitude of uncertainty in the modeled planet mass. Here, we report the direct imaging discovery of a Jovian exoplanet around the Sun-like star GJ 504, detected as part of the SEEDS survey. The system is older than all other known directly-imaged planets; as a result, its estimated mass remains in the planetary regime independent of uncertainties related to choices of initial conditions in the exoplanet modeling. Using the most common exoplanet cooling model, and given the system age of 160(+350/-60) Myr, GJ 504 b has an estimated mass of 4(+4.5/-1.0) Jupiter masses, among the lowest of directly imaged planets. Its projected separation of 43.5 AU exceeds the typical outer boundary of approx.. 30 AU predicted for the core accretion mechanism. GJ 504 b is also significantly cooler (510(+30/-20) K)) and has a bluer color (J - H = -0.23 mag) than previously imaged exoplanets, suggesting a largely cloud-free atmosphere accessible to spectroscopic characterization. Thus, it has the potential of providing novel insights into the origins of giant planets, as well as their atmospheric properties.

  3. Thermal analysis and two-directional air flow thermal management for lithium-ion battery pack

    Science.gov (United States)

    Yu, Kuahai; Yang, Xi; Cheng, Yongzhou; Li, Changhao

    2014-12-01

    Thermal management is a routine but crucial strategy to ensure thermal stability and long-term durability of the lithium-ion batteries. An air-flow-integrated thermal management system is designed in the present study to dissipate heat generation and uniformize the distribution of temperature in the lithium-ion batteries. The system contains of two types of air ducts with independent intake channels and fans. One is to cool the batteries through the regular channel, and the other minimizes the heat accumulations in the middle pack of batteries through jet cooling. A three-dimensional anisotropic heat transfer model is developed to describe the thermal behavior of the lithium-ion batteries with the integration of heat generation theory, and validated through both simulations and experiments. Moreover, the simulations and experiments show that the maximum temperature can be decreased to 33.1 °C through the new thermal management system in comparison with 42.3 °C through the traditional ones, and temperature uniformity of the lithium-ion battery packs is enhanced, significantly.

  4. DIRECT IMAGING OF A COLD JOVIAN EXOPLANET IN ORBIT AROUND THE SUN-LIKE STAR GJ 504

    Energy Technology Data Exchange (ETDEWEB)

    Kuzuhara, M. [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Tamura, M.; Kandori, R.; Hori, Y.; Suzuki, R.; Suenaga, T.; Takahashi, Y. H.; Kwon, J. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Kudo, T. [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A' ohoku Place, Hilo, HI 96720 (United States); Janson, M.; Brandt, T. D.; Spiegel, D.; Burrows, A.; Turner, E. L.; Moro-Martin, A. [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States); Thalmann, C. [Astronomical Institute ' ' Anton Pannekoek' ' , University of Amsterdam, Postbus 94249, 1090 GE, Amsterdam (Netherlands); Biller, B.; Henning, T. [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Carson, J. [Department of Physics and Astronomy, College of Charleston, 58 Coming Street, Charleston, SC 29424 (United States); McElwain, M. W., E-mail: m.kuzuhara@nao.ac.jp [Exoplanets and Stellar Astrophysics Laboratory, Code 667, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); and others

    2013-09-01

    Several exoplanets have recently been imaged at wide separations of >10 AU from their parent stars. These span a limited range of ages (<50 Myr) and atmospheric properties, with temperatures of 800-1800 K and very red colors (J - H > 0.5 mag), implying thick cloud covers. Furthermore, substantial model uncertainties exist at these young ages due to the unknown initial conditions at formation, which can lead to an order of magnitude of uncertainty in the modeled planet mass. Here, we report the direct-imaging discovery of a Jovian exoplanet around the Sun-like star GJ 504, detected as part of the SEEDS survey. The system is older than all other known directly imaged planets; as a result, its estimated mass remains in the planetary regime independent of uncertainties related to choices of initial conditions in the exoplanet modeling. Using the most common exoplanet cooling model, and given the system age of 160{sup +350}{sub -60} Myr, GJ 504b has an estimated mass of 4{sup +4.5}{sub -1.0} Jupiter masses, among the lowest of directly imaged planets. Its projected separation of 43.5 AU exceeds the typical outer boundary of {approx}30 AU predicted for the core accretion mechanism. GJ 504b is also significantly cooler (510{sup +30}{sub -20} K) and has a bluer color (J - H = -0.23 mag) than previously imaged exoplanets, suggesting a largely cloud-free atmosphere accessible to spectroscopic characterization. Thus, it has the potential of providing novel insights into the origins of giant planets as well as their atmospheric properties.

  5. Oblique incidence ion impact pattern formation on Cu(001) along the[100] and [110] azimuthal directions

    Energy Technology Data Exchange (ETDEWEB)

    Everts, Frank; Wormeester, Herbert; Poelsema, Bene [Solid State Physics, MESA, Institute for Nanotechnology, University of Twente, Enschede (Netherlands)

    2010-07-01

    Oblique incidence sputtering is a versatile tool for nanopattern creation on different types of surfaces. Often ripple patterns are observed as a result of an erosion instability. The orientation of the ripples is governed by the polar angle of incidence of the ion beam. High resolution low energy electron diffraction reveal an unanticipated azimuth dependence for Cu(001) at 200 K. Near normal incidence sputtering along[110] gives rise to a diffraction pattern showing a fourfold symmetry of the etch structures. Surprisingly, a further increase of the polar angle shows that this surface imposed fourfold symmetry is preserved up to grazing incidence. In marked contrast are the results for sputtering along the[010] azimuth. Already for near normal incidence the fourfold symmetry in the diffraction pattern is broken, reflecting ripple formation. The orientation of these ripples changes with more oblique incidence sputtering. The explanation for this strong azimuth sensitivity is found by varying the ion energy, showing a strong dependence on the details of the ion substrate interaction.

  6. Ultra-sensitive direct detection of silver ions via Kelvin probe force microscopy.

    Science.gov (United States)

    Park, Jinsung; Lee, Sangmyung; Jang, Kuewhan; Na, Sungsoo

    2014-10-15

    Nanotoxicity is receiving great importance due to its potential impact on human health and environment and due to rapid development in the field of nanoscale research and industry. Herein, we report the Kelvin probe force microscope (KPPM)-based nanotoxicity material detection using surface potential difference. In general, it is difficult to measure the size of ion (Ag(+)) using a conventional atomic force microscope (AFM) because of the limited resolution. In this study, we have demonstrated that KPFM is capable of ultra-sensitive detection of silver ion with silver specific DNA by a single droplet. Furthermore, the measured surface potentials for Ag+ and DNA binding enable the detection performance for a practical sample that is general drinking water. Remarkably, the KPFM based silver ion detection enables an insight into the coordination chemistry, which plays an important role in early detection of toxicity. This implies that KPFM based detection system opens a new avenue for water testing sensor. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Comparison of direct sampling ion trap mass spectrometry to GC/MS for monitoring VOCs in groundwater

    International Nuclear Information System (INIS)

    Wise, M.B.; Merriweather, R.; Guerin, M.; Thompson, C.V.

    1995-01-01

    Rapid analytical methods which utilize Direct Sampling Ion Trap Mass Spectrometry for field screening and compliance monitoring of volatile organic compounds in groundwater have been under development in this laboratory for several years. These methods can be used on fieldable instrumentation, have low ppb detection limits, and require little or no sample preparation. The DSITMS analysis of VOCs in water uses a three minute direct purge of the water sample with a stream of helium at a flow rate of 100 mL/min. VOCs partition into the helium stream and are carried directly into the ion trap via a 100 um section of fused silica capillary. Most of the sample is vented through an open/split interface, with only about 1 mL/min. entering the mass spectrometer. Analysis of the VOCs is accomplished by alternating conditions in the ion trap at roughly one second intervals between electron ionization and chemical ionization (water reagent gas). Two such methods for the analysis of VOCs in water have been submitted to EPA for regulatory approval, and in order to facilitate this process, validation studies have been conducted comparing the DSITMS method to a standard method such as purge-and-trap GC/MS. One such study, recently completed, involved the analysis of over 100 groundwater samples collected from the Oak Ridge reservation for compliance monitoring. Split samples of the groundwater were analyzed by DSITMS and by purge-and-trap GC/MS at a local CLP laboratory. The results of the comparative study generally show excellent qualitative and quantitative agreement between the DSITMS and standard methods, with the DSITMS method being superior with respect to speed, cost, ease of use, and minimized artifacts

  8. Direct analysis of volatile fatty acids in marine sediment porewater by two-dimensional ion chromatography-mass spectrometry

    DEFF Research Database (Denmark)

    Glombitza, Clemens; Pedersen, Jeanette; Røy, Hans

    2014-01-01

    Volatile fatty acids (VFAs) are key intermediates in the microbial food web. However, the analysis of low concentrations of VFAs in marine porewater is hampered by interference from high concentrations of inorganic ions. Published methods often use sample pretreatment, including distillation...... or derivatization, to overcome this problem. This is not only labor intensive but also increases the risk of contamination. We have developed an analytical procedure that enables the direct quantification of several VFAs (formate, acetate, propionate, butyrate, valerate, pyruvate, and lactate) in marine porewater...

  9. Direct etching of SiO2 and Al2O3 by 900-keV gold ions

    OpenAIRE

    Glass, Gary A.; Dias, Johnny Ferraz; Dymnikov, Alexander D.; Houston, Louis M.; Rout, Bibhudutta

    2009-01-01

    We report the direct etching of Al2O3 and SiO2 using 900-keV Au+ ions. 2000-mesh Cu grids were employed as masks using two different configurations: 1 the Cu mesh was placed on top of each insulator separately and independent irradiations were performed, and 2 the Al2O3 and SiO2 substrates were positioned in an edge-to-edge configuration with a single Cu grid providing a common mask to both insulators. Scanning electron microscopy SEM analysis revealed quite different patterns resulting from ...

  10. Neonatal lesions of orbital frontal areas 11/13 in monkeys alter goal-directed behavior but spare fear conditioning and safety signal learning.

    Directory of Open Access Journals (Sweden)

    Andy M Kazama

    2014-03-01

    Full Text Available Recent studies in monkeys have demonstrated that damage to the lateral subfields of orbital frontal cortex (OFC areas 11/13 yields profound changes in flexible modulation of goal-directed behaviors and a lack in fear regulation. Yet, little consideration has been placed on its role in emotional and social development throughout life. The current study investigated the effects of neonatal lesions of the OFC on the flexible modulation of goal-directed behaviors and fear responses in monkeys. Infant monkeys received neonatal lesions of OFC areas 11/13 or sham-lesions during the first post-natal week. Modulation of goal-directed behaviors was measured with a devaluation task at 3-4 years and 6-7 years. Modulation of fear reactivity by safety signals was assessed with the AX+/BX- potentiated-startle paradigm at 6-7 years. Similar to adult-onset OFC lesions, selective neonatal lesions of OFC areas 11/13 yielded a failure to modulate behavioral responses guided by changes in reward value, but spared the ability to modulate fear responses in the presence of safety signals. These results suggest that these areas play a critical role in the development of behavioral adaptation during goal-directed behaviors, but not, or less so, in the development of the ability to process emotionally salient stimuli and to modulate emotional reactivity using environmental contexts, which could be supported by other OFC subfields, such as the most ventromedial subfields (i.e. areas 14/25. Given similar impaired decision-making abilities and spared modulation of fear followed both neonatal lesions of either OFC areas 11 and 13 or amygdala (Kazama et al., 2012; Kazama & Bachevalier, 2013, the present results suggest that interactions between these two neural structures play a critical role in the development of behavioral adaptation; an ability essential for the self-regulation of emotion and behavior that assures the maintenance of successful social relationships.

  11. Direct evidence of the existence of Mn3+ ions in MnTiO3

    Science.gov (United States)

    Maurya, R. K.; Sharma, Priyamedha; Patel, Ashutosh; Bindu, R.

    2017-08-01

    We investigate the room temperature electronic properties of MnTiO3 synthesised by different preparation conditions. For this purpose, we prepared MnTiO3 under two different cooling rates, one is naturally cooled while the other is quenched in liq.nitrogen. The samples were studied using optical absorbance, photoemission spectroscopy and band structure calculations. We observe significant changes in the structural parameters as a result of quenching. Interestingly, in the parent compound, our combined core level, valence band and optical absorbance studies give evidence of the Mn existence in both 2+ and 3+ states. The fraction of Mn3+ ions has been found to increase on quenching MnTiO3 suggests an increase in oxygen non-stoichiometry. The increase in the fraction of the Mn3+ ions has been manifested a) as slight enhancement in the intensity of the optical absorbance in the visible region. There occurs persistent photo-resistance when the incident light is terminated after shining; b) in the behaviour of the features (close to Fermi level) in the valence band spectra. Hence, the combined analysis of the core level, valence band and optical absorbance spectra suggests that the charge carriers are hole like which further leads to the increase in the electrical conductivity of the quenched sample. The present results provide a recipe to tune the optical absorption in the visible range for its applications in optical sensors, solar cell, etc.

  12. Future directions in intermediate energy heavy ion physics. A proposed expansion of the Holifield Facility

    International Nuclear Information System (INIS)

    1986-02-01

    A proposal is presented for a major accelerator addition to the Holifield Heavy Ion Research Facility. The expanded facility will provide ion beams of mass 1 to 238 amu with a combination of energy, intensity, momentum resolution, and beam quality not currently available at any other facility in North America. The physics motivation for such an addition is discussed, and involves physics dominated by meson-exchange forces, Coulomb-force dominated physics, and possibly a regime where the quark and gluon degrees of freedom are significant. The physics research would include topics in atomic and interdisciplinary areas as well as nuclear physics. Some remarks are made on the merits of Oak Ridge as a site for this facility, placing the proposal in some historical perspective. The accelerator system is then described, giving the required beam properties, and the parameters of the synchrotron ring components, injection, ring magnets, RF systems, vacuum system, and electron cooling system and stochastic cooling system requirements. Also described are such facilities as buildings, beam transport and shielding, and experimental facilities, including target areas

  13. Future directions in intermediate energy heavy ion physics. A proposed expansion of the Holifield Facility

    Energy Technology Data Exchange (ETDEWEB)

    1986-02-01

    A proposal is presented for a major accelerator addition to the Holifield Heavy Ion Research Facility. The expanded facility will provide ion beams of mass 1 to 238 amu with a combination of energy, intensity, momentum resolution, and beam quality not currently available at any other facility in North America. The physics motivation for such an addition is discussed, and involves physics dominated by meson-exchange forces, Coulomb-force dominated physics, and possibly a regime where the quark and gluon degrees of freedom are significant. The physics research would include topics in atomic and interdisciplinary areas as well as nuclear physics. Some remarks are made on the merits of Oak Ridge as a site for this facility, placing the proposal in some historical perspective. The accelerator system is then described, giving the required beam properties, and the parameters of the synchrotron ring components, injection, ring magnets, RF systems, vacuum system, and electron cooling system and stochastic cooling system requirements. Also described are such facilities as buildings, beam transport and shielding, and experimental facilities, including target areas. (LEW)

  14. Response assessment with the CXCR4-directed positron emission tomography tracer [68Ga]Pentixafor in a patient with extranodal marginal zone lymphoma of the orbital cavities.

    Science.gov (United States)

    Herhaus, Peter; Habringer, Stefan; Vag, Tibor; Steiger, Katja; Slotta-Huspenina, Julia; Gerngroß, Carlos; Wiestler, Benedikt; Wester, Hans-Jürgen; Schwaiger, Markus; Keller, Ulrich

    2017-12-01

    CXCR4 belongs to the family of chemokine receptors. Together with its sole known ligand CXCL12 (SDF-1alpha), it has a pivotal role during organogenesis and for homing of hematopoietic stem cells. CXCR4 is overexpressed in various malignancies, and this is often associated with poor prognosis. Therefore, molecular imaging of CXCR4 bears a great potential for diagnostics and selecting patients for CXCR4-directed therapies. The CXCR4-directed positron emission tomography (PET) tracer [ 68 Ga]Pentixafor has been shown to visualize CXCR4 expression in various malignancies in vivo. Whereas this tracer has limitations compared to 18 F-Fluorodeoxyglucose ([ 18 F]FDG) in diagnostic PET imaging in peripheral tumour lesions, it might add valuable information in routine diagnostics and response assessment of tumours in close proximity to the central nervous system (CNS) and malignancies within this organ. As a proof-of-concept, we performed [ 68 Ga]Pentixafor PET imaging in a patient with extranodal marginal zone lymphoma (MZL) of the orbital cavities at diagnosis and for post-therapy response assessment. Compared to routinely conducted [ 18 F]FDG PET, the lymphoma lesions determined by magnetic resonance imaging (MRI) showed high tracer accumulation at diagnosis, which decreased upon treatment. We therefore propose that imaging of CXCR4 with [ 68 Ga]Pentixafor is a potential diagnostic tool for tumours close to or within the CNS and suggest this being studied in clinical trials.

  15. Direct fabrication of nano-gap electrodes by focused ion beam etching

    International Nuclear Information System (INIS)

    Nagase, Takashi; Gamo, Kenji; Kubota, Tohru; Mashiko, Shinro

    2006-01-01

    A simple approach to increase the reliability of nano-gap electrode fabrication techniques is presented. The method is based on maskless sputter etching of Au electrodes using a focused ion beam (FIB) and in-situ monitoring of the etching steps by measuring a current fed to the Au electrodes. The in-situ monitoring is crucial to form nano-gaps much narrower than a FIB spot size. By using this approach, gaps of ∼3-6 nm are fabricated with the high yield of ∼90%, and most of the fabricated nano-gap electrodes showed high resistances of 10 GΩ-1 TΩ. The controllability of the fabrication steps is significantly improved by using triple-layered films consisting of top Ti, Au, and bottom adhesion Ti layers. The applicability of the fabricated nano-gap electrodes to electron transport studies of nano-sized objects is demonstrated by electrical measurement of Au colloidal nano-particles

  16. Measurements of Coulomb Cross Section for Production of Direct Electron-pairs by High Energy Ions at the CERN SPS

    CERN Multimedia

    2002-01-01

    QED predicts copious direct electron pair production by ultrarelativistic heavy nuclei in a high Z medium such as nuclear emulsion. First order QED calculations (combined screening and non-screening) for this process show that 1000@+32 electron pairs above 100~keV energy) should be emitted for a total |1|6O track length of 10.9~m in nuclear emulsion at 200~GeV/AMU. Emulsion exposures with oxygen (and other nuclei if available) at 60 and 200~GeV/AMU will be used to calibrate the energy dependent cross section @s~@j~(1n~E)|2|-|3, whose exponent depends on atomic screening. The oxygen tracks in the developed emulsions will be scanned with a microscope, and the number of direct electron pairs will be counted for individual tracks. The exposed stacks will contain sufficient emulsion (and CR39 plastic to check for possible interactions) that adequate path length will be available for exposures to @$>$~10|4~ions at each energy and ion species. \\\\ \\\\ If the absolute value of this cross section is confirmed as large a...

  17. TRIFLE DIFFERENCE APPROACH TO LOW EARTH ORBITER PRECISION ORBIT DETERMINATION

    OpenAIRE

    Jay Hyoun Kwon; Dorota A. Grejner-Brezinska; Jae Hong Yom; Dong Cheon Lee

    2003-01-01

    A precise kinematic orbit determination (P-KOD) procedure for Low Earth Orbiter(LEO) using the GPS ion-free triple differenced carrier phases is presented. Because the triple differenced observables provide only relative information, the first epoch`s positions of the orbit should be held fixed. Then, both forward and backward filtering was executed to mitigate the effect of biases of the first epoch`s position. p-KOD utilizes the precise GPS orbits and ground stations data from International...

  18. In-Source Laser Spectroscopy with the Laser Ion Source and Trap: First Direct Study of the Ground-State Properties of ^{217,219}Po

    Directory of Open Access Journals (Sweden)

    D. A. Fink

    2015-02-01

    Full Text Available A Laser Ion Source and Trap (LIST for a thick-target, isotope-separation on-line facility has been implemented at CERN ISOLDE for the production of pure, laser-ionized, radioactive ion beams. It offers two modes of operation, either as an ion guide, which performs similarly to the standard ISOLDE resonance ionization laser ion source (RILIS, or as a more selective ion source, where surface-ionized ions from the hot ion-source cavity are repelled by an electrode, while laser ionization is done within a radio-frequency quadrupole ion guide. The first physics application of the LIST enables the suppression of francium contamination in ion beams of neutron-rich polonium isotopes at ISOLDE by more than 1000 with a reduction in laser-ionization efficiency of only 20. Resonance ionization spectroscopy is performed directly inside the LIST device, allowing the study of the hyperfine structure and isotope shift of ^{217}Po for the first time. Nuclear decay spectroscopy of ^{219}Po is performed for the first time, revealing its half-life, α-to-β-decay branching ratio, and α-particle energy. This experiment demonstrates the applicability of the LIST at radioactive ion-beam facilities for the production and study of pure beams of exotic isotopes.

  19. Direct detection and quantification of transition metal ions in human atherosclerotic plaques

    DEFF Research Database (Denmark)

    Stadler, Nadina; Lindner, Robyn A; Davies, Michael Jonathan

    2004-01-01

    OBJECTIVE: The involvement of transition metals in atherosclerosis is controversial. Some epidemiological studies have reported a relationship between iron (Fe) and cardiovascular disease, whereas others have not. Experimental studies have reported elevated levels of iron and copper (Cu) in disea......OBJECTIVE: The involvement of transition metals in atherosclerosis is controversial. Some epidemiological studies have reported a relationship between iron (Fe) and cardiovascular disease, whereas others have not. Experimental studies have reported elevated levels of iron and copper (Cu......) in diseased human arteries but have often used methods that release metal ions from proteins. METHODS AND RESULTS: In this study, we have used the minimally invasive technique of electron paramagnetic resonance (EPR) spectroscopy and inductively coupled plasma mass spectroscopy (ICPMS) to quantify iron...... and copper in ex vivo healthy human arteries and carotid lesions. The EPR spectra detected are characteristic of nonheme Fe(III) complexes. Statistically elevated levels of iron were detected in the intima of lesions compared with healthy controls (0.370 versus 0.022 nmol/mg tissue for EPR, 0.525 versus 0...

  20. Analysis of Hot Ions Detected during Equatorial Orbits of the Cassini Spacecraft at Saturn using the Convected Kappa Distribution Function and a Comparison to Voyager and Galileo Measurements at Jupiter

    Science.gov (United States)

    Kane, M.; Mitchell, D. G.; Carbary, J. F.; Hill, M. E.; Dialynas, K.; Mauk, B.; Krimigis, S. M.

    2017-12-01

    An extensive analysis of Cassini INCA and CHEMS measurements of 5-149 keV ions acquired during all equatorial orbits has been completed using a 3-D convected kappa distribution model. The computed plasma azimuthal speed, expressed as a fraction of the local corotation speed, decreases sharply with increasing distance from Saturn. The oxygen ion profile follows the hydrogen ion trend. For both species, the polar convection speed is the smallest of the 3 velocity components, and is centered about zero, but the radial speed has a significant radially outward component. Further, the radial component is enhanced in the pre-dawn sector. The hydrogen and oxygen temperatures increase with decreasing distance to Saturn. The calculated pattern of convection is consistent with an empirical model of plasma convection that includes outward radial transport and escape of plasma in a dawnside boundary layer of plasma entrained by the dawn magnetosheath flow. When the model convection pattern is scaled to the sub-solar magnetopause distance and to the sizes of Jupiter and Saturn, the pattern agrees with that derived from analysis of hot ions detected by the LECP detector on Voyager and the EPD instrument on Galileo. This and previous analysis of hot ion distributions has shown that the convected kappa distribution, with isotropy assumed in the plasma rest frame, has well described hot ion observed fluxes within a limited range of ion energies and has produced meaningful and ordered physical plasma parameters including plasma bulk velocity vectors, kappa distribution temperature profiles, and the general magnetospheric convection pattern at Jupiter and Saturn.

  1. ORBITAL INJURIES

    Directory of Open Access Journals (Sweden)

    Andrej Kansky

    2002-12-01

    Full Text Available Background. Orbit is involved in 40% of all facial fractures. There is considerable variety in severity, ranging from simple nondisplaced to complex comminuted fractures. Complex comminuted fractures (up to 20% are responsible for the majority of complications and unfavorable results. Orbital fractures are classified as internal orbital fractures, zygomatico-orbital fractures, naso-orbito-ethmoidal fractures and combined fractures. The ophtalmic sequelae of midfacial fractures are usually edema and ecchymosis of the soft tissues, subconjuctival hemorrhage, diplopia, iritis, retinal edema, ptosis, enophthalmos, ocular muscle paresis, mechanical restriction of ocular movement and nasolacrimal disturbances. More severe injuries such as optic nerve trauma and retinal detachments have also been reported. Within the wide range of orbital fractures small group of complex fractures causes most of the sequelae. Therefore identification of severe injuries and adequate treatment is of major importance. The introduction of craniofacial techniques made possible a wide exposure even of large orbital wall defects and their reconstruction by bone grafts. In spite of significant progress, repair of complex orbital wall defects remains a problem even for the experienced surgeons.Results. In 1999 121 facial injuries were treated at our department (Clinical Centre Ljubljana Dept. Of Maxillofacial and Oral Surgery. Orbit was involved in 65% of cases. Isolated inner orbital fractures presented 4% of all fractures. 17 (14% complex cases were treated, 5 of them being NOE, 5 orbital (frame and inner walls, 3 zygomatico-orbital, 2 FNO and 2 maxillo-orbital fractures.Conclusions. Final result of the surgical treatment depends on severity of maxillofacial trauma. Complex comminuted fractures are responsable for most of the unfavorable results and ocular function is often permanently damaged (up to 75% in these fractures.

  2. Studies on plasma direct energy converters for thermal and fusion-produced ions using slanted cusp magnetic and distributed electric fields

    Science.gov (United States)

    Yasaka, Y.; Goto, K.; Taniguchi, A.; Tsuji, A.; Takeno, H.

    2009-07-01

    Two types of direct energy converters, cusp direct energy converter (CUSPDEC) and travelling-wave (TW) DEC, used to produce electricity from thermal ions and fusion products in an advanced fuelled fusion, are investigated using small-scale devices. In CUSPDEC, magnetized electrons are deflected along the field lines of the cusp magnetic field to the line cusp region and collected by an electron collector, while weakly magnetized ions can traverse the separatrix and enter into the point cusp region. Thus, ions are separated from electrons, and flow into an ion collector to produce dc power. Efficiencies of energy conversion of separated ions with large thermal spread of energy are measured to be ~55%. An additional lateral electrode, together with the existing collector, constitutes a two-stage ion collector that provides distributed ion-decelerating fields. From the measured voltage-current characteristics, the efficiency of this collector is estimated to be improved to 65-70%, which is consistent with the calculation. Fusion-produced fast ions enter into TWDEC and are velocity-modulated by RF fields, bunched and then decelerated by RF travelling-wave fields on the decelerator to produce RF power. The TWDEC device has shown that the energies of ions of 3-6 keV can be decreased by 10-15% for a one-wavelength decelerator. This would give a total efficiency of 60-70% for a full-length decelerator. A novel system is being investigated for further improvement, in which the incoming ions are deflected transversely, according to each energy, to form a fan-shaped beam and a distributed electrode array for modulation and deceleration generates travelling-waves appropriate to each ion path depending on the energy.

  3. Novel Approach of Using Nutraceutic-Directed Caloric Antioxidant Density and Ion-Ratio for Evaluating Fruit's Health Quality.

    Science.gov (United States)

    Hsieh, Chiu-Lan; Huang, Shang-Ming; Chen, Li-I; Yu, Chien-Mei; Wong, Cheng-Hsin; Peng, Robert Y

    2016-08-01

    Seven kinds of indigenous fruits and five imported fruits were compared for their "health quality." Methods including the calorific, antioxidant, and ion ratios were carried out. Results indicated the order of content (in mg/100g) was: Ca(2+) , Murcott orange (218.2) > Kiwifruit (200.0) > pineapple (138.5) > Golden kiwi (117.6); Mg(2+) , Pitaya (192.2), banana (88.0), Kiwifruit (63.4), and Golden kiwi (58.4); Zn(2+) , Pitaya (19.53) > pear (10.8) > Kiwifruit (6.09) > Irwin mango (4.58). Cu(2+) , Kiwifruit (0.70) > Red globe grape (0.67) > Golden kiwi (0.65) > Irwin mango (0.42) ≈ Pitaya (0.40). In terms of ion ratio, Pitaya showed Zn(2+) /Cu(2+) (48.8), Mg(2+) /Ca(2+) (6.7) and uniquely possessed selenium 0.002 mg/100 g; for pear, Zn(2+) /Cu(2+) = 37.2, while Kyoho grape, Red globe grape, and Golden kiwi revealed extremely high Fe(2+) /(Co(2+) +Ni(2+) ) ratios. On the other hands, Irwin mango and Pitaya astonishingly contained huge amount of inositol, reaching 3523.2 mg/100 g and 1998.7 mg/100 g, respectively. To evaluate the "health quality" of fruits, an overall ranking method by combining (a) the Function-directed Caloric Antioxidant Density (CAD) and (b) the ion ratio was developed. The finalized ranking of these selected fruits was: Pitaya > cherry > Irwin mango > Murcott orange = pineapple > banana > Golden kiwi > pear > Kiwifruit > Red globe grape > apple > Kyoho grape. Conclusively, this evaluation method is novel, contemporary and scientific, which could more clearly assess the "health quality" of fruits in view of nutritional, calorific, and antioxidant balance. © 2016 Institute of Food Technologists®

  4. Directed flow in heavy-ion collisions at NICA: What is interesting to measure?

    Energy Technology Data Exchange (ETDEWEB)

    Bravina, L.V. [University of Oslo, Department of Physics, Oslo (Norway); National Research Nuclear University ' ' MEPhI' ' , (Moscow Engineering Physics Institute), Moscow (Russian Federation); Goethe University, Frankfurt Institute for Advanced Studies (FIAS), Frankfurt (Germany); Zabrodin, E.E. [University of Oslo, Department of Physics, Oslo (Norway); Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); National Research Nuclear University ' ' MEPhI' ' , (Moscow Engineering Physics Institute), Moscow (Russian Federation); Goethe University, Frankfurt Institute for Advanced Studies (FIAS), Frankfurt (Germany)

    2016-08-15

    We study the formation of the directed flow of hadrons in nuclear collisions at energies between AGS and SPS in Monte Carlo cascade model. The slope of the proton flow at midrapidity tends to zero (softening) with increasing impact parameter of the collision. For very peripheral topologies this slope becomes negative (antiflow). The effect is caused by rescattering of hadrons in remnants of the colliding nuclei. Since the softening of the proton flow can be misinterpreted as indication of the presence of quark-gluon plasma, we propose several measurements at NICA facility which can help one to distinguish between the cases with and without the plasma formation. (orig.)

  5. Ptolemy: a program for heavy-ion direct-reaction calculations

    International Nuclear Information System (INIS)

    Macfarlane, M.H.; Pieper, S.C.

    1978-04-01

    Ptolemy is an IBM/360 program for the computation of nuclear elastic and direct-reaction cross sections. It carries out optical-model fits to elastic-scattering data at one or more energies and for one or more combinations of projectile and target, collective model DWBA calculations of excitation processes, and finite-range DWBA calculations of nucleon-transfer reactions. It is fast and does not require large amounts of core. The input is exceptionally flexible and easy to use. The types of calculations that Ptolemy can carry out are outlined, the formulas used are summarized, and a detailed description of its input is given

  6. Direct Trace Element Analysis of Liquid Blood Samples by In-Air Ion Beam Analytical Techniques (PIXE-PIGE).

    Science.gov (United States)

    Huszank, Robert; Csedreki, László; Török, Zsófia

    2017-02-07

    There are various liquid materials whose elemental composition is of interest in various fields of science and technology. In many cases, sample preparation or the extraction can be complicated, or it would destroy the original environment before the analysis (for example, in the case of biological samples). However, multielement direct analysis of liquid samples can be realized by an external PIXE-PIGE measurement system. Particle-induced X-ray and gamma-ray emission spectroscopy (PIXE, PIGE) techniques were applied in external (in-air) microbeam configuration for the trace and main element determination of liquid samples. The direct analysis of standard solutions of several metal salts and human blood samples (whole blood, blood serum, blood plasma, and formed elements) was realized. From the blood samples, Na, P, S, Cl, K, Ca, Fe, Cu, Zn, and Br elemental concentrations were determined. The focused and scanned ion beam creates an opportunity to analyze very small volume samples (∼10 μL). As the sample matrix consists of light elements, the analysis is possible at ppm level. Using this external beam setup, it was found that it is possible to determine elemental composition of small-volume liquid samples routinely, while the liquid samples do not require any preparation processes, and thus, they can be analyzed directly. In the case of lower concentrations, the method is also suitable for the analysis (down to even ∼1 ppm level) but with less accuracy and longer measurement times.

  7. Direct surface analysis of pesticides on soil, leaves, grass, and stainless steel by static secondary ion mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ingram, J.C.; Groenewold, G.S.; Appelhans, A.D.; Delmore, J.E.; Olson, J.E.; Miller, D.L. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1997-02-01

    Direct surface analyses by static secondary ion mass spectrometry (SIMS) were performed for the following pesticides adsorbed on dandelion leaves, grass, soil, and stainless steel samples: alachlor, atrazine, captan, carbofuran, chlorpyrifos, chlorosulfuron, chlorthal-dimethyl, cypermethrin, 2,4-D, diuron, glyphosate, malathion, methomyl, methyl arsonic acid, mocap, norflurazon, oxyfluorfen, paraquat, temik, and trifluralin. The purpose of this study was to evaluate static SIMS as a tool for pesticide analysis, principally for use in screening samples for pesticides. The advantage of direct surface analysis compared with conventional pesticide analysis methods is the elimination of sample pretreatment including extraction, which streamlines the analysis substantially; total analysis time for SIMS analysis was ca. 10 min/sample. Detection of 16 of the 20 pesticides on all four substrates was achieved. Of the remaining four pesticides, only one (trifluralin) was not detected on any of the samples. The minimum detectable quantity was determined for paraquat on soil in order to evaluate the efficacy of using SIMS as a screening tool. Paraquat was detected at 3 pg/mm{sup 2} (c.a. 0.005 monolayers). The results of these studies suggest that SIMS is capable of direct surface detection of a range of pesticides, with low volatility, polar pesticides being the most easily detected. 25 refs., 2 figs., 2 tabs.

  8. Testing the direct ion storage dosemeter for personal dosimetry in a nuclear research centre and a hospital.

    Science.gov (United States)

    Vanhavere, F; Covens, P

    2010-03-01

    The direct ion storage (DIS) dosemeter can have some clear advantages in personal dosimetry. Before introducing the DIS into practice in the dosimetry service, a series of tests was performed on the linearity, angular and energy dependence, temperature influences and hard resets. After that, for several months, the DIS dosemeters were worn in parallel with the legal dosemeters (thermoluminescent badge) in a nuclear research centre and in several departments of a university hospital. The conclusions are that the DIS has good characteristics to be used as legal personal dosemeter, and that the comparison with the TLD badge is good. Only in interventional radiology and cardiology fields the DIS gives significant lower values than the TLD badge.

  9. Orbital velocity

    OpenAIRE

    Modestino, Giuseppina

    2016-01-01

    The trajectory and the orbital velocity are determined for an object moving in a gravitational system, in terms of fundamental and independent variables. In particular, considering a path on equipotential line, the elliptical orbit is naturally traced, verifying evidently the keplerian laws. The case of the planets of the solar system is presented.

  10. ORBITAL, CELLULITIS

    African Journals Online (AJOL)

    Aim: The purpose of this study was to assess the prevalence of paranasal sinusitis as a cause of orbital cellulitis and to identify the commonest sinus(es) involved in our setting. Methods: A retrospective review of the case notes of 47 patients with orbital cellulitis admitted into the ophthalmic ward of the University College ...

  11. The slow collisional E×B ion drift characterized as the major instability mechanism of a poorly magnetized plasma column with an inward-directed radial electric field

    Energy Technology Data Exchange (ETDEWEB)

    Pierre, Thiéry [Centre National de la Recherche Scientifique, UMR 7345 Laboratoire PIIM, Aix*Marseille University, Marseille (France)

    2016-04-15

    The low-frequency instability of a cylindrical poorly magnetized plasma with an inward-directed radial electric field is studied changing the gas pressure and the ion cyclotron frequency. The unstable frequency always decreases when the gas pressure is increased indicating collisional effects. At a fixed pressure, the unstable frequency increases with the magnetic field when the B-field is low and decreases at larger magnetic field strength. We find that the transition between these two regimes is obtained when the ion cyclotron frequency equals the ion-neutrals collision frequency. This is in agreement with the theory of the slow-ion drift instability induced by the collisional slowing of the electric ion drift [A. Simon, Phys. Fluids 6, 382 (1963)].

  12. Acoustic signals generated in piezoelectric lead-zirconate-titanate elements by direct bombardment with xenon ions

    International Nuclear Information System (INIS)

    Miyachi, T.; Nakamura, Y.; Kuraza, G.; Fujii, M.; Nagashima, A.; Hasebe, N.; Kobayashi, M.N.; Kobayashi, S.; Miyajima, M.; Mori, K.; Okudaira, O.; Yamashita, N.; Shibata, H.; Murakami, T.; Uchihori, Y.; Okada, N.

    2006-01-01

    Acoustic signals were observed with a lead-zirconate-titanate (PZT) element that was directly irradiated with a 368 MeV/n xenon beam. Using an array comprising PZT elements, the energy loss in the PZT was studied. These elements are sensitive to an energy deposit of 100 nJ. A series of values of output voltage vs. integrated thickness of PZT was represented along a line similar to the ionization loss calculated by the Bethe-Bloch formula. The induced voltage was attributed to several processes-ionization, thermal, elastic, and piezoelectric processes. This study describes the possible applications of the PZT element as an active medium for calorimeters and a monitor for hypervelocity impact of space dust

  13. Direct photons from relativistic heavy ion collisions at CERN SPS and at RHIC

    CERN Document Server

    Chaudhuri, A K

    2002-01-01

    Assuming QGP as the initial state, we have analyzed the direct photon data, obtained by the WA98 collaboration, in 158 A GeV Pb+Pb collisions at CERN SPS. It was shown, that for small thermalisation time, two loop rate contribute substantially to high $p_T$ photons. We argue that for extremely short thermalisation time scale, the higher loop contribution should not be neglected. For thermalisation time 0.4 fm or greater, when higher loop contribution are not substantial, the initial temperature of the QGP is not large and the system does not produce enough hard $p_T$ photons to fit the WA98 experiment. For initial time in the ranges of 0.4-1.0 fm, WA98 data could be fitted only if the fluid has initial radial velocity in the range of 0.3-0.5c. The model was applied to predict photon spectrum at RHIC energy.

  14. Direct Exchange Mechanism for Interlayer Ions in Non-Swelling Clays.

    Science.gov (United States)

    Ruiz Pestana, Luis; Kolluri, Kedarnath; Head-Gordon, Teresa; Lammers, Laura Nielsen

    2017-01-03

    The mobility of radiocesium in the environment is largely mediated by cation exchange in micaceous clays, in particular Illite-a non-swelling clay mineral that naturally contains interlayer K + and has high affinity for Cs + . Although exchange of interlayer K + for Cs + is nearly thermodynamically nonselective, recent experiments show that direct, anhydrous Cs + -K + exchange is kinetically viable and leads to the formation of phase-separated interlayers through a mechanism that remains unclear. Here, using classical atomistic simulations and density functional theory calculations, we identify a molecular-scale positive feedback mechanism in which exchange of the larger Cs + for the smaller K + significantly lowers the migration barrier of neighboring K + , allowing exchange to propagate rapidly once initiated at the clay edge. Barrier lowering upon slight increase in layer spacing (∼0.7 Å) during Cs + exchange is an example of "chemical-mechanical coupling" that likely explains the observed sharp exchange fronts leading to interstratification. Interestingly, we find that these features are thermodynamically favored even in the absence of a heterogeneous layer charge distribution.

  15. Distorted-wave theory of electron-ion collisions. I. Direct excitation and ionization

    International Nuclear Information System (INIS)

    Hahn, Y.

    1977-01-01

    A simple modification of the Bethe approximation for high-energy electron-atom collisions is considered for the purpose of analyzing the medium-energy scattering by highly stripped ionic targets. The effect of amplitude and phase distortions of the projectile-electron wave function on the excitation and ionization cross sections is approximately taken into account using the Elwert factor and the eikonal procedure, respectively. To facilitate the cross-section calculation further, the momentum-transfer-dependent part in the excitation matrix element is factored out in terms of an average transfer. The energy dependence of the various modification factors is studied in detail, showing that the distortion effect is large for ionic targets and decays only slowly with the scattering energy, as E/sup -1/2/. For a neutral target, however, the distortion effects roughly cancel with each other, thus resulting in the effectiveness of the unmodified Bethe cross section at much lower energies than one usually expects. The improved formalism is applied to estimate the total cross sections for the direct excitation and ionization of outer-shell electrons of the ionic target. The results are drastically changed from the unmodified Bethe approximation, and are generally in fair agreement with experimental data for all energies except in the threshold region

  16. Cloud-based opportunities in scientific computing: insights from processing Suomi National Polar-Orbiting Partnership (S-NPP) Direct Broadcast data

    Science.gov (United States)

    Evans, J. D.; Hao, W.; Chettri, S.

    2013-12-01

    The cloud is proving to be a uniquely promising platform for scientific computing. Our experience with processing satellite data using Amazon Web Services highlights several opportunities for enhanced performance, flexibility, and cost effectiveness in the cloud relative to traditional computing -- for example: - Direct readout from a polar-orbiting satellite such as the Suomi National Polar-Orbiting Partnership (S-NPP) requires bursts of processing a few times a day, separated by quiet periods when the satellite is out of receiving range. In the cloud, by starting and stopping virtual machines in minutes, we can marshal significant computing resources quickly when needed, but not pay for them when not needed. To take advantage of this capability, we are automating a data-driven approach to the management of cloud computing resources, in which new data availability triggers the creation of new virtual machines (of variable size and processing power) which last only until the processing workflow is complete. - 'Spot instances' are virtual machines that run as long as one's asking price is higher than the provider's variable spot price. Spot instances can greatly reduce the cost of computing -- for software systems that are engineered to withstand unpredictable interruptions in service (as occurs when a spot price exceeds the asking price). We are implementing an approach to workflow management that allows data processing workflows to resume with minimal delays after temporary spot price spikes. This will allow systems to take full advantage of variably-priced 'utility computing.' - Thanks to virtual machine images, we can easily launch multiple, identical machines differentiated only by 'user data' containing individualized instructions (e.g., to fetch particular datasets or to perform certain workflows or algorithms) This is particularly useful when (as is the case with S-NPP data) we need to launch many very similar machines to process an unpredictable number of

  17. Vortex Laser based on III-V semiconductor metasurface: direct generation of coherent Laguerre-Gauss modes carrying controlled orbital angular momentum.

    Science.gov (United States)

    Seghilani, Mohamed S; Myara, Mikhael; Sellahi, Mohamed; Legratiet, Luc; Sagnes, Isabelle; Beaudoin, Grégoire; Lalanne, Philippe; Garnache, Arnaud

    2016-12-05

    The generation of a coherent state, supporting a large photon number, with controlled orbital-angular-momentum L = ħl (of charge l per photon) presents both fundamental and technological challenges: we demonstrate a surface-emitting laser, based on III-V semiconductor technology with an integrated metasurface, generating vortex-like coherent state in the Laguerre-Gauss basis. We use a first order phase perturbation to lift orbital degeneracy of wavefunctions, by introducing a weak anisotropy called here "orbital birefringence", based on a dielectric metasurface. The azimuthal symmetry breakdown and non-linear laser dynamics create "orbital gain dichroism" allowing selecting vortex handedness. This coherent photonic device was characterized and studied, experimentally and theoretically. It exhibits a low divergence (50 dB vortex purity), and single frequency operation in a stable low noise regime (0.1% rms). Such high performance laser opens the path to widespread new photonic applications.

  18. The Hot Orbit: Orbital Cellulitis

    Science.gov (United States)

    Chaudhry, Imtiaz A.; Al-Rashed, Waleed; Arat, Yonca O.

    2012-01-01

    Orbital cellulitis is an uncommon condition previously associated with severe complications. If untreated, orbital cellulitis can be potentially sight and life threatening. It can affect both adults and children but has a greater tendency to occur in the pediatric age group. The infection most commonly originates from sinuses, eyelids or face, retained foreign bodies, or distant soources by hematogenous spread. It is characterized by eyelid edema, erythema, chemosis, proptosis, blurred vision, fever, headache, and double vision. A history of upper respiratory tract infection prior to the onset is very common especially in children. In the era prior to antibiotics, vision loss from orbital cellulitis was a dreaded complication. Currently, imaging studies for detection of orbital abcess, the use of antibiotics and early drainage have mitigated visual morbidity significantly. The purpose of this review is to describe current investigative strategies and management options in the treatment of orbital cellulitis, establish their effectiveness and possible complications due to late intervention. PMID:22346113

  19. Foreign body orbital cyst

    DEFF Research Database (Denmark)

    Yazdanfard, Younes; Heegard, Steffen; Fledelius, Hans C.

    2001-01-01

    Ophthalmology, penetrating orbital injury, orbital foreign body, ultrasound, computed tomography (CT), histology......Ophthalmology, penetrating orbital injury, orbital foreign body, ultrasound, computed tomography (CT), histology...

  20. Effect of the Ion Mass and Energy on the Response of 70-nm SOI Transistors to the Ion Deposited Charge by Direct Ionization

    International Nuclear Information System (INIS)

    Raine, M.; Gaillardin, M.; Sauvestre, J.E.; Flament, O.; Bournel, A.; Aubry-Fortuna, V.

    2010-01-01

    The response of SOI transistors under heavy ion irradiation is analyzed using Geant4 and Synopsys Sentaurus device simulations. The ion mass and energy have a significant impact on the radial ionization profile of the ion deposited charge. For example, for an identical LET, the higher the ion energy per nucleon, the wider the radial ionization track. For a 70-nm SOI technology, the track radius of high energy ions (≥ 10 MeV/a) is larger than the transistor sensitive volume; part of the ion charge recombines in the highly doped source or drain regions and does not participate to the transistor electric response. At lower energy (≤ 10 MeV/a), as often used for ground testing, the track radius is smaller than the transistor sensitive volume, and the entire charge is used for the transistor response. The collected charge is then higher, corresponding to a worst-case response of the transistor. Implications for the hardness assurance of highly-scaled generations are discussed. (authors)

  1. Ion Rings for Magnetic Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Greenly, John, B.

    2005-07-31

    of a reactor-scale FRC, and the FIREX program was intended to test the ideas behind this approach. We will describe in this report the technological development path and advances in physics understanding that allowed FIREX to reach a regime in which ion rings were reproducibly created with up to about half the current necessary to produce field reversal. Unfortunately, the experiments were limited to this level by a fundamental, unanticipated aspect of the physics of strong ion rings in plasma. The FIREX ring is a strongly anisotropic, current-carrying population of ions moving faster than the Alfven speed in the background plasma. The rapidly changing ring current excites very large-amplitude Alfven waves in the plasma, and these waves strongly affect the ring, causing rapid energy loss in a way that is not compatible with the success of the ring trapping scenario around which FIREX was designed. The result was that FIREX rings were always very short-lived. We will discuss the implication of these results for possible future use of large-orbit ions in FRCs. In short, it appears that a certain range of the parameters characterizing the ring Alfven mach number and distribution function must be avoided to allow the existence of a long-lived energetic ion component in an FRC. This report will explain why FIREX experimental results cannot be directly scaled to quantitatively predict this range for a particular FRC configuration. This will require accurate, three-dimensional simulations. FIREX results do constitute a very good dataset for validating such a code, and simulations already carried out during this program provide a guide to the important physics involved.

  2. Metallic and/or oxygen ion implantation into AlN ceramics as a method of preparation for its direct bonding with copper

    International Nuclear Information System (INIS)

    Barlak, M.; Borkowska, K.; Olesinska, W.; Kalinski, D.; Piekoszewski, J.; Werner, Z.; Jagielski, J.; Sartowska, B.

    2006-01-01

    Direct bonding (DB) process is recently getting an increasing interest as a method for producing high quality joints between aluminum nitride (AlN) ceramics and copper. The metallic ions were implanted using an MEVVA type TITAN implanter with unseparated beam. Oxygen ions were implanted using a semi-industrial ion implanter without mass separation equipped with a gaseous ion source. The substrate temperature did not exceed 200 o C. Ions were implanted at two acceleration voltages, i.e. 15 and 70 kV. The fluence range was between 1·E16 and 1·E18 cm -2 . After implantation, some of the samples were characterized by the Rutherford backscattering (RBS) method. In conclusion: (a) The investigations performed in the present work confirm an assumption that ion implantation is a very promising technique as a pretreatment of AlN ceramics for the formation of the joints with copper in direct bonding process. (b) It has been shown that titanium implantation gives the best results in comparison to other metals examined (Fe, Cr, Cu) but also in comparison to double Ti+O and O+Ti implantations

  3. Effects of fast monoenergetic electrons on the ion dynamics near the cathode in a pulsed direct current plasma sheath

    International Nuclear Information System (INIS)

    Sharifian, M.; Shokri, B.

    2008-01-01

    A detailed one-dimensional simulation of the ion dynamics of the plasma sheath near a substrate (cathode) in the presence of fast monoenergetic electrons has been carried out in this article. The sheath evolution is investigated by using a fluid model assuming that the ions, plasma electrons and monoenergetic, fast electrons act as three fluids (fluid approach). The effect of the density of fast electrons on the ion density, ion velocity, and ion energy near the cathode and the evolution of the sheath boundary in front of the cathode are separately explored. Also, the variation of the ion velocity and ion density at the vicinity of the cathode as a function of time is investigated in the absence and presence of the electron beam. Results indicate that the presence of fast electrons in the sheath causes significant change in the sheath thickness and therefore basically changes the ion velocity, ion density, and ion impact energy on the cathode compared to the absence of the electron beam case

  4. Direct Imprinting of Scalable, High-Performance Woodpile Electrodes for Three-Dimensional Lithium-Ion Nanobatteries.

    Science.gov (United States)

    Li, Wenhao; Zhou, Yiliang; Howell, Irene R; Gai, Yue; Naik, Aditi R; Li, Shengkai; Carter, Kenneth R; Watkins, James J

    2018-02-14

    The trend of device downscaling drives a corresponding need for power source miniaturization. Though numerous microfabrication methods lead to successful creation of submillimeter-scale electrodes, scalable approaches that provide cost-effective nanoscale resolution for energy storage devices such as on-chip batteries remain elusive. Here, we report nanoimprint lithography (NIL) as a direct patterning technique to fabricate high-performance TiO 2 nanoelectrode arrays for lithium-ion batteries (LIBs) over relatively large areas. The critical electrode dimension is below 200 nm, which enables the structure to possess favorable rate capability even under discharging current densities as high as 5000 mA g -1 . In addition, by sequential imprinting, electrodes with three-dimensional (3D) woodpile architecture were readily made in a "stack-up" manner. The height of architecture can be easily controlled by the number of stacked layers while maintaining nearly constant surface-to-volume ratios. The result is a proportional increase of areal capacity with the number of layers. The structure-processing combination leads to efficient use of the material, and the resultant specific capacity (250.9 mAh g -1 ) is among the highest reported. This work provides a simple yet effective strategy to fabricate nanobatteries and can be potentially extended to other electroactive materials.

  5. Unambiguous identification and discovery of bacterial siderophores by direct injection 21 Tesla Fourier transform ion cyclotron resonance mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Lawrence R.; Tfaily, Malak M.; Shaw, Jared B.; Hess, Nancy J.; Pasa Tolic, Ljiljana; Koppenaal, David W.

    2017-01-01

    Under iron-limiting conditions, bacteria produce low molecular mass Fe(III) binding molecules known as siderophores to sequester the Fe(III), along with other elements, increasing their bioavailibility. Siderophores are thought to influence iron cycling and biogeochemistry in both marine and terrestrial ecosystems and hence the need for rapid, confident characterization of these compounds has increased. In this study, the type of siderophores produced by two marine bacterial species, Synechococcus sp. PCC 7002 and Vibrio cyclitrophicus 1F53, were characterized using a newly developed 21T Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FTICR MS) with direct injection electrospray ionization. This technique allowed for the rapid detection of synechobactins from Synechococcus sp. PCC 7002 as well as amphibactins from Vibrio cyclitrophicus 1F53 based on high mass accuracy and resolution allowing for observation of specific Fe isotopic peaks and fine isotopic structure enables highly confident identification of these sideropohores. When combined with molecular network analysis two new amphibactins were discovered and verified by tandem MS. These results show that high-field FTICR MS is a powerful technique that will greatly improve the ability to rapidly identify and discover metal binding species in the environment.

  6. Focused ion beam modification of surfaces for directed self-assembly of InAs/GaAs(001) quantum dots

    International Nuclear Information System (INIS)

    McKay, Hugh; Rudzinski, Paul; Dehne, Aaron; Millunchick, Joanna Mirecki

    2007-01-01

    Controlled nucleation of InAs quantum dots has been achieved by Ga + focused ion beam modification of GaAs(100) surfaces. Quantum dots may be induced in irradiated regions despite the fact that the deposited thickness is less than the critical thickness for their formation under typical growth conditions when the ion dose is greater than 10 13 ions cm -2 . We also find that the dot density increases with increasing ion dose, and reaches saturation for D>10 14 ions cm -2 . Parameters such as dot height and diameter are unaffected by the dose level. Thus, we show that the increase in dot density is a result of diffusion of adatoms from outside the patterned region. The mechanism for enhanced quantum dot formation is due to the formation of monolayer deep holes created in the substrate by the ion beam, which may be used to form regular arrays of quantum dots

  7. Congenital orbital encephalocele, orbital dystopia, and exophthalmos.

    Science.gov (United States)

    Hwang, Kun; Kim, Han Joon

    2012-07-01

    We present here an exceedingly rare variant of a nonmidline basal encephalocele of the spheno-orbital type, and this was accompanied with orbital dystopia in a 56-year-old man. On examination, his left eye was located more inferolaterally than his right eye, and the patient said this had been this way since his birth. The protrusion of his left eye was aggravated when he is tired. His naked visual acuity was 0.7/0.3, and the ocular pressure was 14/12 mm Hg. The exophthalmometry was 10/14 to 16 mm. His eyeball motion was not restricted, yet diplopia was present in all directions. The distance from the midline to the medial canthus was 20/15 mm. The distance from the midline to the midpupillary line was 35/22 mm. The vertical dimension of the palpebral fissure was 12/9 mm. The height difference of the upper eyelid margin was 11 mm, and the height difference of the lower eyelid margin was 8 mm. Facial computed tomography and magnetic resonance imaging showed left sphenoid wing hypoplasia and herniation of the left anterior temporal pole and dura mater into the orbit, and this resulted into left exophthalmos and encephalomalacia in the left anterior temporal pole. To the best of our knowledge, our case is the second case of basal encephalocele and orbital dystopia.

  8. Response of thermal ions to electromagnetic ion cyclotron waves

    Science.gov (United States)

    Anderson, B. J.; Fuselier, S. A.

    1994-01-01

    Electromagnetic ion cyclotron waves generated by 10 - 50 keV protons in the Earth's equatorial magnetosphere will interact with the ambient low-energy ions also found in this region. We examine H(+) and He(+) distribution functions from approx. equals 1 to 160 eV using the Hot Plasma Composition Experiment instrument on AMPTE/CCE to investigate the thermal ion response to the waves. A total of 48 intervals were chosen on the basis of electromagnetic ion cyclotron (EMIC) wave activity: 24 with prevalent EMIC waves and 24 with no EMIC waves observed on the orbit. There is a close correlation between EMIC waves and perpendicular heated ion distributions. For protons the perpendicular temperature increase is modest, about 5 eV, and is always observed at 90 deg pitch angles. This is consistent with a nonresonant interaction near the equator. By contrast, He(+) temperatures during EMIC wave events averaged 35 eV and sometimes exceeded 100 eV, indicating stronger interaction with the waves. Furthermore, heated He(+) ions have X-type distributions with maximum fluxes occurring at pitch angles intermediate between field-aligned and perpendicular directions. The X-type He(+) distributions are consistent with a gyroresonant interaction off the equator. The concentration of He(+) relative to H(+) is found to correlate with EMIC wave activity, but it is suggested that the preferential heating of He(+) accounts for the apparent increase in relative He(+) concentration by increasing the proportion of He(+) detected by the ion instrument.

  9. Direct view on the phase evolution in individual LiFePO4 nanoparticles during Li-ion battery cycling

    NARCIS (Netherlands)

    Zhang, X.; Van Hulzen, M.; Singh, D.P.; Brownrigg, A.W.; Wright, J.P.; Van Dijk, N.H.; Wagemaker, M.

    2015-01-01

    Phase transitions in Li-ion electrode materials during (dis)charge are decisive for battery performance, limiting high-rate capabilities and playing a crucial role in the cycle life of Li-ion batteries. However, the difficulty to probe the phase nucleation and growth in individual grains is

  10. Direct observation of interaction between plasma ions and grid-excited pulses in a Q-machine

    DEFF Research Database (Denmark)

    Andersen, S.A.; Jensen, Vagn Orla; Michelsen, Poul

    1970-01-01

    The change in velocity-distribution function caused by interaction between ions and density pulses in a Q-machine is observed experimentally.......The change in velocity-distribution function caused by interaction between ions and density pulses in a Q-machine is observed experimentally....

  11. [Orbital exenteration].

    Science.gov (United States)

    Benazzou, S; Arkha, Y; Boulaadas, M; Essakalli, L; Kzadri, M

    2011-04-01

    Orbital exenteration is a disfiguring surgery. The surgery is mostly performed for advanced neoplasms of the eyelid in an attempt to achieve cure with tumor free margins. Reconstruction is a real challenge, especially in elderly patients with significant comorbidities. We operated 15 patients presenting with palpebral and orbital tumors, between January 2000 and December 2007. We collected the clinical data concerning patients, tumor, treatment, and recurrences. Ten male and five female patients with a mean age of 56 years at diagnosis presented with ulcerative palpebral malignant tumor, and impaired ocular motility. Basal cell carcinoma was the most common (80%). All patients underwent exenteration, (subtotal three, total eight, and extended four patients). The cavity was filled with a temporal muscle flap in ten cases, Mustardé flap in three cases, latissimus dorsi myocutaneous free flap in one case, and a jugal V-Y flap in one case. The mean follow-up was 23 months with good healing without radiotherapy tissue alteration. Four patients had a recurrence and one patient died from metastases. The goals of reconstruction are functional and esthetic. Given the initial tumoral extension, we choose to use a regional or microsurgical flap for functional reconstruction. The flap provides a good cutaneous coverage, rapid healing, closure of orbital nasal and sinus communications, or of orbital and cranial communications. It is not damaged by radiotherapy. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  12. Orbit analysis

    International Nuclear Information System (INIS)

    Michelotti, L.

    1995-01-01

    We take an overview of recently developed methods for studying single particle orbits in accelerators and discuss some physics underlying those which involve Lie operators. It will be further argued that object-oriented programming provides the appropriate computing strategy in which to model accelerators and to implement these techniques

  13. Kinetic method of ruthenium ion traces determination, basing on the reaction of oxidation of direct blue 6B, by means of hydrogen peroxide

    International Nuclear Information System (INIS)

    Suwinska, T.; Gregorowicz, A.; Matysek-Majewska, D.

    1980-01-01

    A sensitive and selective method of determination of ruthenium ion traces (1.10 - 3 μg/cm 3 ) has been worked out. The method is based on oxidation of direct blue 6B by hydrogen peroxide under acidic conditions at pH = 0,8 - 1,2 in the presence of ruthenium ions as catalyst. The method has been applied for determination of ruthenium traces in Pt, PdCl 2 , PtCl 4 and RhCl 3 .n H 2 O. In these materials ruthenium has been determined within the range of 1,10 - 2 % - 5,10 - 4 %. (author)

  14. Direct experimental evidence for a negative heat capacity in the liquid-to-gas like phase transition in hydrogen cluster ions backbending of the caloric curve

    CERN Document Server

    Gobet, F; Carré, M; Farizon, B; Farizon, M; Gaillard, M J; Maerk, T D; Scheier, P

    2002-01-01

    By (i) selecting specific decay reactions in high energy collisions (60 keV/amu) of hydrogen cluster ions with a helium target (utilizing event-by-event data of a recently developed multi-coincidence experiment) and by (ii) deriving corresponding temperatures for these microcanonical cluster ensembles (analyzing the respective fragment distributions) we are able to construct caloric curves for ii sub 3 sup + (ii sub 2) sub m cluster ions (6 <= m <= 14). All individual curves and the mean of these curves show a backbending in the plateau region thus constituting direct evidence for a negative microcanonical heat capacity in the liquid-to-gas like transition of these finite systems.

  15. Direct Analysis in Real Time (DART) of an Organothiophosphate at Ultrahigh Resolution by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and Tandem Mass Spectrometry.

    Science.gov (United States)

    Prokai, Laszlo; Stevens, Stanley M

    2016-01-16

    Direct analysis in real time (DART) is a recently developed ambient ionization technique for mass spectrometry to enable rapid and sensitive analyses with little or no sample preparation. After swab-based field sampling, the organothiophosphate malathion was analyzed using DART-Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS) and tandem mass spectrometry (MS/MS). Mass resolution was documented to be over 800,000 in full-scan MS mode and over 1,000,000 for an MS/MS product ion produced by collision-induced dissociation of the protonated analyte. Mass measurement accuracy below 1 ppm was obtained for all DART-generated ions that belonged to the test compound in the mass spectra acquired using only external mass calibration. This high mass measurement accuracy, achievable at present only through FTMS, was required for unequivocal identification of the corresponding molecular formulae.

  16. Direct Analysis of Organic Compounds in Liquid Using a Miniature Photoionization Ion Trap Mass Spectrometer with Pulsed Carrier-Gas Capillary Inlet.

    Science.gov (United States)

    Lu, Xinqiong; Yu, Quan; Zhang, Qian; Ni, Kai; Qian, Xiang; Tang, Fei; Wang, Xiaohao

    2017-08-01

    A miniature ion trap mass spectrometer with capillary direct sampling and vacuum ultraviolet photoionization source was developed to conduct trace analysis of organic compounds in liquids. Self-aspiration sampling is available where the samples are drawn into the vacuum chamber through a capillary with an extremely low flow rate (less than 1 μL/min), which minimizes sample consumption in each analysis to tens of micrograms. A pulsed gas-assisted inlet was designed and optimized to promote sample transmission in the tube and facilitate the cooling of ions, thereby improving instrument sensitivity. A limit of detection of 2 ppb could be achieved for 2,4-dimethylaniline in a methanol solution. The sampling system described in the present study is specifically suitable for a miniature photoionization ion trap mass spectrometer that can perform rapid and online analysis for liquid samples. Graphical Abstract ᅟ.

  17. Jupiter icy moons orbiteer mission design overview

    Science.gov (United States)

    Sims, Jon A.

    2006-01-01

    An overview of the design of a mission to three large moons of Jupiter is presented. the Jupiter Icy Moons Orbiter (JIMO) mission uses ion thrusters powered by a nuclear reactor to transfer from Earth to Jupiter and enter a low-altitude science orbit around each of the moons.

  18. A feasibility study on direct methanol fuel cells for laptop computers based on a cost comparison with lithium-ion batteries

    Science.gov (United States)

    Wee, Jung-Ho

    This paper compares the total cost of direct methanol fuel cell (DMFC) and lithium (Li)-ion battery systems when applied as the power supply for laptop computers in the Korean environment. The average power output and operational time of the laptop computers were assumed to be 20 W and 3000 h, respectively. Considering the status of their technologies and with certain conditions assumed, the total costs were calculated to be US140 for the Li-ion battery and US362 for DMFC. The manufacturing costs of the DMFC and Li-ion battery systems were calculated to be 16.65 W -1 and 0.77 W h -1, and the energy consumption costs to be 0.00051 W h -1 and 0.00032 W h -1, respectively. The higher fuel consumption cost of the DMFC system was due to the methanol (MeOH) crossover loss. Therefore, the requirements for DMFCs to be able to compete with Li-ion batteries in terms of energy cost include reducing the crossover level to at an order magnitude of -9 and the MeOH price to under 0.5 kg -1. Under these conditions, if the DMFC manufacturing cost could be reduced to 6.30 W -1, then the DMFC system would become at least as competitive as the Li-ion battery system for powering laptop computers in Korea.

  19. A feasibility study on direct methanol fuel cells for laptop computers based on a cost comparison with lithium-ion batteries

    International Nuclear Information System (INIS)

    Wee, Jung-Ho

    2007-01-01

    This paper compares the total cost of direct methanol fuel cell (DMFC) and lithium (Li)-ion battery systems when applied as the power supply for laptop computers in the Korean environment. The average power output and operational time of the laptop computers were assumed to be 20 W and 3000 h, respectively. Considering the status of their technologies and with certain conditions assumed, the total costs were calculated to be US$140 for the Li-ion battery and US$362 for DMFC. The manufacturing costs of the DMFC and Li-ion battery systems were calculated to be $16.65 W -1 and $0.77 W h -1 , and the energy consumption costs to be $0.00051 W h -1 and $0.00032 W h -1 , respectively. The higher fuel consumption cost of the DMFC system was due to the methanol (MeOH) crossover loss. Therefore, the requirements for DMFCs to be able to compete with Li-ion batteries in terms of energy cost include reducing the crossover level to at an order magnitude of -9 and the MeOH price to under $0.5 kg -1 . Under these conditions, if the DMFC manufacturing cost could be reduced to $6.30 W -1 , then the DMFC system would become at least as competitive as the Li-ion battery system for powering laptop computers in Korea. (author)

  20. Directly connected series coupled HTPEM fuel cell stacks to a Li-ion battery DC bus for a fuel cell electrical vehicle

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Ashworth, Leanne; Remón, Ian Natanael

    2008-01-01

    The work presented in this paper examines the use of pure hydrogen fuelled high temperature polymer electrolyte membrane (HTPEM) fuel cell stacks in an electrical car, charging a Li-ion battery pack. The car is equipped with two branches of two series coupled 1 kW fuel cell stacks which...... are connected directly parallel to the battery pack during operation. This enables efficient charging of the batteries for increased driving range. With no power electronics used, the fuel cell stacks follow the battery pack voltage, and charge the batteries passively. This saves the electrical and economical...... losses related to these components and their added system complexity. The new car battery pack consists of 23 Li-ion battery cells and the charging and discharging are monitored by a battery management system (BMS) which ensures safe operating conditions for the batteries. The direct connection...

  1. Field-Induced Co(II) Single-Ion Magnets with mer-Directing Ligands but Ambiguous Coordination Geometry.

    Science.gov (United States)

    Peng, Yan; Mereacre, Valeriu; Anson, Christopher E; Zhang, Yiquan; Bodenstein, Tilmann; Fink, Karin; Powell, Annie K

    2017-06-05

    Three air-stable Co(II) mononuclear complexes with different aromatic substituents have been prepared and structurally characterized by single-crystal X-ray diffraction. The mononuclear complexes [Co(H 2 L1) 2 ]·2THF (1), [Co(HL2) 2 ] (2), and [Co(H 2 L3) 2 ]·CH 2 Cl 2 (3) (where H 3 L1, H 2 L2, and H 3 L3 represent 3-hydroxy-naphthalene-2-carboxylic acid (6-hydroxymethyl-pyridin-2-ylmethylene) hydrazide, nicotinic acid (6-hydroxymethyl-pyridin-2-ylmethylene) hydrazide, and 2-hydroxy-benzoic acid (6-hydroxymethyl-pyridin-2-ylmethylene) hydrazide, respectively) feature a distorted mer octahedral coordination geometry. Detailed magnetic studies of 1-3 have been conducted using direct and alternating current magnetic susceptibility data. Field-induced slow magnetic relaxation was observed for these three complexes. There are few examples of such behavior in (distorted) octahedral coordination geometry (OC) Co(II) mononuclear complexes with uniaxial anisotropy. Analysis of the six-coordinate Co(II) mononuclear single-ion magnets (SIMs) in the literature using the SHAPE program revealed that they all show what is best described as distorted trigonal prismatic (TRP) coordination geometry, and in general, these show negative D zero-field splitting (ZFS) values. On the other hand, all the Co(II) mononuclear complexes displaying what is best approximated as distorted octahedral (OC) coordination geometry show positive D values. In the new Co(II) mononuclear complexes we describe here, there is an ambiguity, since the rigid tridentate ligands confer what is best described for an octahedral complex as a mer coordination geometry, but the actual shape of the first coordination sphere is between octahedral and trigonal prismatic. The negative D values observed experimentally and supported by high-level electronic structure calculations are thus in line with a trigonal prismatic geometry. However, a consideration of the rhombicity as indicated by the E value of the ZFS in

  2. Direct evaluation of radiobiological parameters from clinical data in the case of ion beam therapy: an alternative approach to the relative biological effectiveness

    International Nuclear Information System (INIS)

    Cometto, A; Russo, G; Giordanengo, S; Marchetto, F; Cirio, R; Attili, A; Bourhaleb, F; Milian, F M

    2014-01-01

    The relative biological effectiveness (RBE) concept is commonly used in treatment planning for ion beam therapy. Whether models based on in vitro/in vivo RBE data can be used to predict human response to treatments is an open issue. In this work an alternative method, based on an effective radiobiological parameterization directly derived from clinical data, is presented. The method has been applied to the analysis of prostate cancer trials with protons and carbon ions. Prostate cancer trials with proton and carbon ion beams reporting 5 year-local control (LC5) and grade 2 (G2) or higher genitourinary toxicity rates (TOX) were selected from literature to test the method. Treatment simulations were performed on a representative subset of patients to produce dose and linear energy transfer distribution, which were used as explicative physical variables for the radiobiological modelling. Two models were taken into consideration: the microdosimetric kinetic model (MKM) and a linear model (LM). The radiobiological parameters of the LM and MKM were obtained by coupling them with the tumor control probability and normal tissue complication probability models to fit the LC5 and TOX data through likelihood maximization. The model ranking was based on the Akaike information criterion. Results showed large confidence intervals due to the limited variety of available treatment schedules. RBE values, such as RBE = 1.1 for protons in the treated volume, were derived as a by-product of the method, showing a consistency with current approaches. Carbon ion RBE values were also derived, showing lower values than those assumed for the original treatment planning in the target region, whereas higher values were found in the bladder. Most importantly, this work shows the possibility to infer the radiobiological parametrization for proton and carbon ion treatment directly from clinical data. (paper)

  3. Direct evaluation of radiobiological parameters from clinical data in the case of ion beam therapy: an alternative approach to the relative biological effectiveness.

    Science.gov (United States)

    Cometto, A; Russo, G; Bourhaleb, F; Milian, F M; Giordanengo, S; Marchetto, F; Cirio, R; Attili, A

    2014-12-07

    The relative biological effectiveness (RBE) concept is commonly used in treatment planning for ion beam therapy. Whether models based on in vitro/in vivo RBE data can be used to predict human response to treatments is an open issue. In this work an alternative method, based on an effective radiobiological parameterization directly derived from clinical data, is presented. The method has been applied to the analysis of prostate cancer trials with protons and carbon ions.Prostate cancer trials with proton and carbon ion beams reporting 5 year-local control (LC5) and grade 2 (G2) or higher genitourinary toxicity rates (TOX) were selected from literature to test the method. Treatment simulations were performed on a representative subset of patients to produce dose and linear energy transfer distribution, which were used as explicative physical variables for the radiobiological modelling. Two models were taken into consideration: the microdosimetric kinetic model (MKM) and a linear model (LM). The radiobiological parameters of the LM and MKM were obtained by coupling them with the tumor control probability and normal tissue complication probability models to fit the LC5 and TOX data through likelihood maximization. The model ranking was based on the Akaike information criterion.Results showed large confidence intervals due to the limited variety of available treatment schedules. RBE values, such as RBE = 1.1 for protons in the treated volume, were derived as a by-product of the method, showing a consistency with current approaches. Carbon ion RBE values were also derived, showing lower values than those assumed for the original treatment planning in the target region, whereas higher values were found in the bladder. Most importantly, this work shows the possibility to infer the radiobiological parametrization for proton and carbon ion treatment directly from clinical data.

  4. Improvement in the assessment of direct and facilitated ion transfers by electrochemically induced redox transformations of common molecular probes

    DEFF Research Database (Denmark)

    Zhou, Min; Gan, Shiyu; Zhong, Lijie

    2012-01-01

    the interface and the charge neutrality of the organic film (containing an extremely hydrophobic electrolyte) can only be maintained by the injection of ions from the aqueous phase. Taking advantage of this fact, common redox probes, such as ferrocene (Fc) and 7,7,8,8-tetracyanoquinodimethane (TCNQ), which...... potential window (ppw) in the aqueous phase and, as a result, this allowed the assessment of weakly assisted ion transfers, which appear at the terminal of the ppw at single polarized interfaces; (ii) without introducing the tetraphenylarsonium–tetraphenylborate (TPAs–TPB) thermodynamic assumption, one can...

  5. Inflammation of the Orbit

    Science.gov (United States)

    ... Glaucoma (Video) Macular Degeneration Additional Content Medical News Inflammation of the Orbit (Inflammatory Orbital Pseudotumor) By James ... Introduction to Eye Socket Disorders Cavernous Sinus Thrombosis Inflammation of the Orbit Orbital Cellulitis Preseptal Cellulitis Tumors ...

  6. Decree 243/994 National Direction of Especial Subjects it create and will operate in the orbit of the External Relation Ministere

    International Nuclear Information System (INIS)

    1994-01-01

    Creates in the Ministry of External Relationships the Direction of Special Matters, to which concerns to study, to coordinate and to execute in the pertinent thing, the foreign policy of the Republic in the related with Nuclear Energy, Dismantle, human rights and Humanitarian Right, Population, Migration and Refugees, Drug traffic, Terrorism, Space Right and all those topics of political character that require to be considered in form separated by their special characteristic . The Direction of Special Political Matters in opinion of the Ministry of External Relationships will depend directly on the General Direction for Political Matters [es

  7. Transfer of Direct and Moiré Patterns by Reactive Ion Etching Through Ex Situ Fabricated Nanoporous Polymer Masks

    DEFF Research Database (Denmark)

    Shvets, Violetta; Hentschel, Thomas; Schulte, Lars

    2015-01-01

    hexagonal packing of 10 nm pores with a principal period of 20 nm. We demonstrate the transfer of the hexagonal pattern onto silicon by means of reactive ion etching through the masks. In addition, patterns elliptic and slit-like holes on silicon are obtained by utilizing masks cut at 45 degrees relative...

  8. Extended analysis of satellite structures in particle induced X-ray emission spectra using molecular orbital calculations

    Science.gov (United States)

    Uda, U.

    Methods for estimating intensity distributions of X-ray satellite spectra induced by accelerated ions with energies of a few McVlamu are reviewed, where the orbitals responsible for X-ray emission are written in the molecular frame, not in the atomic frame. The ionization cross section is written here in the frame of the direct Coulomb interaction and the shake process. The following two factors are taken into account: (1) changes in the number of orbital electrons due to molecular orbital formation and (2) deviation of the number of electric charges on the projectile ion from the nuclear charge Z. Here the semiclassical approximation (SCA) has been used to calculate the Coulomb interaction between the projectile ion and the orbital electrons. In order to estimate the intensity of X-rays emitted from multiply ionized states changes in the fluorescence yield from the yield of isolated atoms caused by resonant orbital rearrangement (ROR), were also taken into account. Furthermore the energy loss of the projectile ions and absorption of emitted X-rays in the material were taken into account. The agreement between the calculated and the observed X-ray satellite intensities is satisfactory when we use all the correction terms mentioned above.

  9. Orbital flower

    Science.gov (United States)

    Szucs-Csillik, Iharka

    2017-11-01

    The regularizing techniques known as Kustaanheimo-Stiefel (KS) transformation have investigated. It has proved that it is very useful in n-body simulations, where it helps to handle close encounters. This paper shows how the basic transformation is a starting point for a family of polynomial coupled function. This interpretation becomes simply on writing KS transformations in quaternion form, which also helps to derive concise expressions for regularized equations of motion. Even if the KS regularization method is more easy to use, it is interesting to encapsulate the KS transformation in a family of methods, which all conserve the KS transformations' properties. Further, an interesting point of view is considering, the orbital shapes of the restricted three-body problem (also regularized restricted three-body problem) for different initial conditions has compared with flower pattern.

  10. Time-Integral Correlations of Multiple Variables With the Relativistic-Electron Flux at Geosynchronous Orbit: The Strong Roles of Substorm-Injected Electrons and the Ion Plasma Sheet

    Science.gov (United States)

    Borovsky, Joseph E.

    2017-12-01

    Time-integral correlations are examined between the geosynchronous relativistic electron flux index Fe1.2 and 31 variables of the solar wind and magnetosphere. An "evolutionary algorithm" is used to maximize correlations. Time integrations (into the past) of the variables are found to be superior to time-lagged variables for maximizing correlations with the radiation belt. Physical arguments are given as to why. Dominant correlations are found for the substorm-injected electron flux at geosynchronous orbit and for the pressure of the ion plasma sheet. Different sets of variables are constructed and correlated with Fe1.2: some sets maximize the correlations, and some sets are based on purely solar wind variables. Examining known physical mechanisms that act on the radiation belt, sets of correlations are constructed (1) using magnetospheric variables that control those physical mechanisms and (2) using the solar wind variables that control those magnetospheric variables. Fe1.2-increasing intervals are correlated separately from Fe1.2-decreasing intervals, and the introduction of autoregression into the time-integral correlations is explored. A great impediment to discerning physical cause and effect from the correlations is the fact that all solar wind variables are intercorrelated and carry much of the same information about the time sequence of the solar wind that drives the time sequence of the magnetosphere.

  11. An improved method for direct estimation of free cyanide in drinking water by Ion Chromatography-Pulsed Amperometry Detection (IC-PAD) on gold working electrode.

    Science.gov (United States)

    Kumar Meher, Alok; Labhsetwar, Nitin; Bansiwal, Amit

    2018-02-01

    In the present work a fast, reliable and safe Ion Exchange Chromatography-Pulsed Amperometry Detection (IC-PAD) method for direct determination of free cyanide in drinking water has been reported. To the best of our knowledge for the first time we are reporting the application of Gold working electrode for detection of free cyanide in a chromatography system. The system shows a wide linear range up to 8000µg/L. The electrode was found to have improved sensitivity and selectivity in the presence of interfering ions. The detection limit of the system was calculated to be 2µg/L. Long term evaluation of the electrode was found to be stable. Reproducible results were obtained from analysis of drinking water samples with recoveries of 98.3-101.2% and Relative Standard Deviations (RSD) of application of the newly developed method for the analysis of free cyanide in drinking water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Selective area growth of InAs nanowires from SiO2/Si(1 1 1) templates direct-written by focused helium ion beam technology

    Science.gov (United States)

    Yang, Che-Wei; Chen, Wei-Chieh; Chou, Chieh; Lin, Hao-Hsiung

    2018-02-01

    We report on the selective area growth of InAs nanowires on patterned SiO2/Si (1 1 1) nano-holes, prepared by focused helium ion beam technology. We used a single spot mode, in which the focused helium ion beam was fixed on a single point with a He+-ion dosage, ranging from 1.5 pC to 8 pC, to drill the nano-holes. The smallest hole diameter achieved is ∼8 nm. We found that low He+-ion dosage is able to facilitate the nucleation of (1 1 1)B InAs on the highly mismatched Si, leading to the vertical growth of InAs nanowires (NWs). High He-ion dosage, on the contrary, severely damaged Si surface, resulting in tilted and stripe-like NWs. In addition to titled NW grown from (1 1 1)A InAs domain, a new titled growth direction due to defect induced twinning was observed. Cross-sectional TEM images of vertical NWs show mixed wurtizite (WZ) and zincblende (ZB) phases, while WZ phase dominants. The stacking faults resulting from the phase change is proportional to NW diameter, suggesting that the critical diameter of phase turning is larger than 110 nm, the maximum diameter of our NWs. Period of misfit dislocation at the InAs/Si interface of vertical NW is also found larger than the theoretical value when the diameter of heterointerface is smaller than 50 nm, indicating that the small contact area is able to accommodate the large lattice and thermal mismatch between InAs and Si.

  13. Direct observation of electronic nematicity in charge and orbital ordered La0.33Ca0.67MnO3

    Science.gov (United States)

    Tao, J.; Sun, K.; Zuo, J. M.; Zhu, Y.

    2013-03-01

    Nematic and smectic states have been demonstrated to be very important in understanding high-Tc superconductivity. Here we report similar observations of electronic nematicity in doped manganites. Both the electron diffraction results and HRTEM images obtained from single crystal domain of La0.33Ca0.67MnO3 clearly show a C4 to C2 symmetry broken in charge ordered (CO) and orbital ordered superstructures at intermediate temperature range. The electronic nematicity persists in the crystal until long-range CO forms as a stripe phase at lower temperatures upon cooling. During warming process, we observed topological defects in the charge ordering superstructures, indicating that the melting of the CO superstructure is defect mediated. Theoretical simulations will also be provided for better interpretation of the phenomenon. Research at Brookhaven National Laboratory was sponsored by the US Department of Energy (DOE)/Basic Energy Sciences, Materials Sciences and Engineering Division under Contract DE-AC02-98CH10886.

  14. Orbital science's 'Bermuda Triangle'

    Science.gov (United States)

    Sherrill, Thomas J.

    1991-02-01

    The effects of a part of the inner Van Allen belt lying closest to the earth, known as the South Atlantic Anomaly (SAA) upon spacecraft including the Hubble Space Telescope (HST), are discussed. The area consists of positively charged ions and electrons from the Van Allen Belt which become trapped in the earth's dipole field. Contor maps representing the number of protons per square centimeter per second having energies greater than 10 million electron volts are presented. It is noted that the HST orbit causes it to spend about 15 percent of its time in the SAA, but that, unlike the experience with earlier spacecraft, the satellite's skin, internal structure, and normal electronic's packaging provides sufficient protection against eletrons, although some higher energy protons still get through. Various charged particle effects which can arise within scientific instruments including fluorescence, Cerenkov radiation, and induced radioactivity are described.

  15. Ponderomotive beatwave ion acceleration using twisted light

    Science.gov (United States)

    Saberi, Hossein; Vieira, Jorge; Silva, Luis O.

    2017-10-01

    An all-optical mechanism of ion acceleration in vacuum with two counter-propagating plane waves has been proposed by F. Peano et al., IEEE Trans Plasma Sci. 36, 1857 (2008). A suitable frequency chirping of lasers drives a beat wave with variable phase velocity that traps particles and accelerates them longitudinally. In this paper, direct ion acceleration by two counter-propagating focused laser beams with variable frequencies is considered, and the multi-dimensional effects associated with the finite transverse dimension of lasers are investigated. It is shown that the Gaussian laser beams provide a defocusing transverse force that stops the acceleration process as ions propagate towards regions of smaller laser fields. On the other hand, the Laguerre-Gaussian laser beams with identical orbital angular momentum can confine the off-axis ions radially as they accelerate to high energies. It is shown that the orbital angular momentum of the Laguerre-Gaussian lasers can be used to control the angular momentum of the accelerated ion beam.

  16. Direct observation of the vacancy structure of a (220) platelet in an ion-irradiated platinum--4.0 at. % gold alloy

    International Nuclear Information System (INIS)

    Wei, C.Y.; Seidman, D.N.

    1977-06-01

    A detailed field-ion microscope (FIM) study has been made of the vacancy structure of a (220) platelet created by a single 30 keV W + ion in a platinum-4.0 at. percent gold alloy; the specimen was maintained at 40 0 K (below substage II/sub B/) during the in-situ irradiation at approximately 2 x 10 -9 torr. Prior to the pulsed field-evaporation dissection of the specimen at 40 0 K it was warmed isochronally to 100 0 K (above substage II/sub c/). The (220) platelet was found to consist of 31 vacant lattice sites, lying in four (220) planes, and clustered in a disc-shaped region which is approximately 20 A in diameter. If only first nearest-neighbor lattice sites are considered then the distribution of cluster sizes is as follows: (1) two monovacancies; and (2) one jumbo vacancy cluster containing 29 vacancies. The range of the vacancy concentration within the (220) vacancy platelet is approximately 35 to 44 at. percent. Employing the modified Kinchin-Pease equation it was calculated that the displacement efficiency (kappa) for this platelet is 0.12. It is suggested that the prismatic dislocation loops lying on [220] type planes, observed by transmission electron microscopy, in ion or fast-neutron irradiated platinum can form as a result of the direct collapse of [220] type vacancy platelets

  17. Direct electron and ion fluid computation of high electrostatic fields in dense inhomogeneous plasmas with subsequent nonlinear optical and dynamical laser interaction

    International Nuclear Information System (INIS)

    Lalousis, P.

    1984-01-01

    Nonthermal direct electrodynamic interaction between laser energy and a fully ionized plasma was studied. The particular emphasis is on the action of nonlinear forces, in which the optical electromagnetic fields act on the plasma electrons which then transfer their energy to the ions electrostatically. Instead of the usual single fluid model, the plasma is treated as two separate conducting fluids for electrons and ions, coupled by momentum and Coulomb interactions. The equations governing the two fluids are derived from first principles, and numerical algorithms for computing these equations are developed, enabling the plasma oscillatons to be resolved and studied. Fully ionized plasma expansion without laser irradiation is studied first numerically. Remarkable damping mechanisms by coupling to ion oscillations have been observed. Inhomogeneities in densities of the two fluids result in large electrostatic fields and double layers are generated. There is quite close agreement between numerically calculated electrostatic fields and analytical solutions. Laser interaction with fully ionized plasma is also studied numerically. The generation of cavitons is numerically observed, and it is inferred that laser plasma interactions produce very high electrostatic fields in the vicinity of cavitons. It is further shown that charge neutrality is not necessarily maintained in a caviton

  18. TRIFLE DIFFERENCE APPROACH TO LOW EARTH ORBITER PRECISION ORBIT DETERMINATION

    Directory of Open Access Journals (Sweden)

    Jay Hyoun Kwon

    2003-03-01

    Full Text Available A precise kinematic orbit determination (P-KOD procedure for Low Earth Orbiter(LEO using the GPS ion-free triple differenced carrier phases is presented. Because the triple differenced observables provide only relative information, the first epoch`s positions of the orbit should be held fixed. Then, both forward and backward filtering was executed to mitigate the effect of biases of the first epoch`s position. p-KOD utilizes the precise GPS orbits and ground stations data from International GPS Service (IGS so that the only unknown parameters to be solved are positions of the satellite at each epoch. Currently, the 3-D accuracy off-KOD applied to CHAMP (CHAllenging Min-isatellite Payload shows better than 35 cm compared to the published rapid scientific orbit (RSO solution from GFZ (GeoForschungsZentrum Potsdam. The data screening for cycle slips is a particularly challenging procedure for LEO, which moves very fast in the middle of the ionospheric layer. It was found that data screening using SNR (signal to noise ratio generates best results based on the residual analysis using RSO. It is expected that much better accuracy are achievable with refined prescreening procedure and optimized geometry of the satellites and ground stations.

  19. Triple Difference Approach to Low Earth Orbiter Precision Orbit Determination

    Science.gov (United States)

    Kwon, Jay-Hyoun; Grejner-Brzezinska, Dorota A.; Yom, Jae-Hong; Cheon, Lee-Dong

    2003-03-01

    A precise kinematic orbit determination (P-KOD) procedure for Low Earth Orbiter(LEO) using the GPS ion-free triple differenced carrier phases is presented. Because the triple differenced observables provide only relative information, the first epoch's positions of the orbit should be held fixed. Then, both forward and backward filtering was executed to mitigate the effect of biases of the first epoch's position. P-KOD utilizes the precise GPS orbits and ground stations data from International GPS Service (IGS) so that the only unknown parameters to be solved are positions of the satellite at each epoch. Currently, the 3-D accuracy of P-KOD applied to CHAMP (CHAllenging Minisatellite Payload) shows better than 35 cm compared to the published rapid scientific orbit (RSO) solution from GFZ (GeoForschungsZentrum Potsdam). The data screening for cycle slips is a particularly challenging procedure for LEO, which moves very fast in the middle of the ionospheric layer. It was found that data screening using SNR (signal to noise ratio) generates best results based on the residual analysis using RSO. It is expected that much better accuracy are achievable with refined prescreening procedure and optimized geometry of the satellites and ground stations.

  20. NASA Orbital Debris Baseline Populations

    Science.gov (United States)

    Krisko, Paula H.; Vavrin, A. B.

    2013-01-01

    The NASA Orbital Debris Program Office has created high fidelity populations of the debris environment. The populations include objects of 1 cm and larger in Low Earth Orbit through Geosynchronous Transfer Orbit. They were designed for the purpose of assisting debris researchers and sensor developers in planning and testing. This environment is derived directly from the newest ORDEM model populations which include a background derived from LEGEND, as well as specific events such as the Chinese ASAT test, the Iridium 33/Cosmos 2251 accidental collision, the RORSAT sodium-potassium droplet releases, and other miscellaneous events. It is the most realistic ODPO debris population to date. In this paper we present the populations in chart form. We describe derivations of the background population and the specific populations added on. We validate our 1 cm and larger Low Earth Orbit population against SSN, Haystack, and HAX radar measurements.

  1. Direct fabrication of a W-C SNS Josephson junction using focused-ion-beam chemical vapour deposition

    International Nuclear Information System (INIS)

    Dai, Jun; Kometani, Reo; Ishihara, Sunao; Warisawa, Shin’ichi; Onomitsu, Koji; Krockenberger, Yoshiharu; Yamaguchi, Hiroshi

    2014-01-01

    A tungsten-carbide (W-C) superconductor/normal metal/superconductor (SNS) Josephson junction has been fabricated using focused-ion-beam chemical vapour deposition (FIB-CVD). Under certain process conditions, the component ratio has been tuned from W: C: Ga = 26%: 66%: 8% in the superconducting wires to W: C: Ga = 14%: 79%: 7% in the metallic junction. The critical current density at 2.5 K in the SNS Josephson junction is 1/3 of that in W-C superconducting nanowire. Also, a Fraunhofer-like oscillation of critical current in the junction with four periods is observed. FIB-CVD opens avenues for novel functional superconducting nanodevices. (paper)

  2. Orbital-Specific observation of O2p and Ni3d electrons in LiNi0.5Mn0.5O2, a cathode material for lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Yoshinori Satou

    2017-09-01

    Full Text Available Cathode materials for lithium-ion batteries containing Ni2+ have attracted much interest because of their high theoretical capacity. However, the precise electronic structures of these cathode materials have not yet been clearly observed, especially the energy positions of the O2p and Ni3d orbitals and the shape of the density of states. The aim of this study was to investigate the relative energy positions and shape of the density of states of O2p and Ni3d for LiNi0.5Mn0.5O2 experimentally. We cleaved a LiNi0.5Mn0.5O2 pellet in an Ar-filled glove box and performed synchrotron ultraviolet photoelectron spectroscopy for different photon energies, which enabled us to investigate the relative cross-section intensity of O2p and Ni3d. As a result, the valence-band structure was determined. We found that O2p electrons are itinerant and exist in the vicinity of the Fermi energy more than Ni3d electrons. Ni3d electrons are more localized and spread mainly from 1.2–1.5 eV below the Fermi energy. To validate the electronic structure, we measured the synchrotron O K-edge X-ray absorption fine structure of electrochemically lithium-extracted LiNi0.5Mn0.5O2. The electronic structure demonstrated that ligand holes in the oxygen atoms form below the Fermi level during the initial stage of Li extraction and that the formation rate of the holes decreases with Li extraction.

  3. Orbital-Specific observation of O2p and Ni3d electrons in LiNi0.5Mn0.5O2, a cathode material for lithium-ion batteries

    Science.gov (United States)

    Satou, Yoshinori; Komine, Shigeki; Shimizu, Sumera

    2017-09-01

    Cathode materials for lithium-ion batteries containing Ni2+ have attracted much interest because of their high theoretical capacity. However, the precise electronic structures of these cathode materials have not yet been clearly observed, especially the energy positions of the O2p and Ni3d orbitals and the shape of the density of states. The aim of this study was to investigate the relative energy positions and shape of the density of states of O2p and Ni3d for LiNi0.5Mn0.5O2 experimentally. We cleaved a LiNi0.5Mn0.5O2 pellet in an Ar-filled glove box and performed synchrotron ultraviolet photoelectron spectroscopy for different photon energies, which enabled us to investigate the relative cross-section intensity of O2p and Ni3d. As a result, the valence-band structure was determined. We found that O2p electrons are itinerant and exist in the vicinity of the Fermi energy more than Ni3d electrons. Ni3d electrons are more localized and spread mainly from 1.2-1.5 eV below the Fermi energy. To validate the electronic structure, we measured the synchrotron O K-edge X-ray absorption fine structure of electrochemically lithium-extracted LiNi0.5Mn0.5O2. The electronic structure demonstrated that ligand holes in the oxygen atoms form below the Fermi level during the initial stage of Li extraction and that the formation rate of the holes decreases with Li extraction.

  4. ERS orbit control

    Science.gov (United States)

    Rosengren, Mats

    1991-12-01

    The European remote sensing mission orbit control is addressed. For the commissioning phase, the orbit is defined by the following requirements: Sun synchronous, local time of descending node 10:30; three days repeat cycle with 43 orbital revolutions; overhead Venice tower (12.508206 deg east, 45.314222 deg north). The launch, maneuvers for the initial acquisition of the operational orbit, orbit maintenance maneuvers, evaluation of the orbit control, and the drift of the inclination are summarized.

  5. WINCS on-orbit performance results

    Science.gov (United States)

    Nicholas, Andrew C.; Herrero, Fred A.; Stephan, Andrew W.; Finne, Theodore

    2015-09-01

    The Winds-Ions-Neutral Composition Suite (WINCS) instrument, also known as the Small Wind and Temperature Spectrometer (SWATS), was designed and developed jointly by the Naval Research Laboratory (NRL) and NASA/Goddard Space Flight Center (GSFC) for ionosphere-thermosphere investigations in orbit between 120 and 550 km altitude. The WINCS instrument houses four spectrometers in a single package with size, weight, and power compatible with a CubeSat. These spectrometers provide the following measurements: neutral winds, neutral temperature, neutral density, neutral composition, ion drifts, ion temperature, ion density and ion composition. The instrument is currently operating on the International Space Station and on the STP-Sat3 spacecraft. Data from the Ion-Drift Temperature-Spectrometer (IDTS) are used to compute the ion drift, temperature, and density in the presence of large changes in spacecraft potential. A summary is given of future flight manifests.

  6. Phonons with orbital angular momentum

    International Nuclear Information System (INIS)

    Ayub, M. K.; Ali, S.; Mendonca, J. T.

    2011-01-01

    Ion accoustic waves or phonon modes are studied with orbital angular momentum (OAM) in an unmagnetized collissionless uniform plasma, whose constituents are the Boltzmann electrons and inertial ions. For this purpose, we have employed the fluid equations to obtain a paraxial equation in terms of ion density perturbations and discussed its Gaussian beam and Laguerre-Gauss (LG) beam solutions. Furthermore, an approximate solution for the electrostatic potential problem is presented, allowing to express the components of the electric field in terms of LG potential perturbations. The energy flux due to phonons is also calculated and the corresponding OAM is derived. Numerically, it is shown that the parameters such as azimuthal angle, radial and angular mode numbers, and beam waist, strongly modify the profiles of the phonon LG potential. The present results should be helpful in understanding the phonon mode excitations produced by Brillouin backscattering of laser beams in a uniform plasma.

  7. First direct evidence of meso-scale variability on ion-neutral dynamics using co-located tristatic FPIs and EISCAT radar in Northern Scandinavia

    Directory of Open Access Journals (Sweden)

    A. L. Aruliah

    2005-01-01

    Full Text Available This paper presents the first direct empirical evidence that mesoscale variations in ion velocities must be taken into consideration when calculating Joule heating and relating it to changes in ion temperatures and momentum transfer to the neutral gas. The data come from the first tristatic Fabry-Perot Interferometer (FPI measurements of the neutral atmosphere co-located with tristatic measurements of the ionosphere made by the European Incoherent Scatter (EISCAT radar which were carried out during the nights of 27-28 February 2003 and 28 February until 1 March 2003. Tristatic measurements mean that there are no assumptions of uniform wind fields and ion drifts, nor zero vertical winds. The independent, tristatic, thermospheric measurements presented here should provide unambiguous vector wind information, and hence reduce the need to supplement observations with information obtained from models of the neutral atmosphere, or with estimates of neutral parameters derived from ionospheric measurements. These new data can also test the assumptions used in models and in ion-neutral interactions. The FPIs are located close to the 3 radars of the EISCAT configuration in northern Scandinavia, which is a region well covered by a network of complementary instruments. These provide a larger scale context within which to interpret our observations of mesoscale variations on the scales of tens of kilometres spatially and minutes temporally. Initial studies indicate that the thermosphere is more dynamic and responsive to ionospheric forcing than expected. Calculations using the tristatic volume measurements show that the magnitude of the neutral wind dynamo contribution was on average 29% of Joule heating during the first night of observation. At times it either enhanced or reduced the effective electric field by up to several tens of percent. The tristatic experiment also presents the first validation of absolute temperature measurements from a common

  8. First direct evidence of meso-scale variability on ion-neutral dynamics using co-located tristatic FPIs and EISCAT radar in Northern Scandinavia

    Directory of Open Access Journals (Sweden)

    A. L. Aruliah

    2005-01-01

    Full Text Available This paper presents the first direct empirical evidence that mesoscale variations in ion velocities must be taken into consideration when calculating Joule heating and relating it to changes in ion temperatures and momentum transfer to the neutral gas. The data come from the first tristatic Fabry-Perot Interferometer (FPI measurements of the neutral atmosphere co-located with tristatic measurements of the ionosphere made by the European Incoherent Scatter (EISCAT radar which were carried out during the nights of 27-28 February 2003 and 28 February until 1 March 2003. Tristatic measurements mean that there are no assumptions of uniform wind fields and ion drifts, nor zero vertical winds. The independent, tristatic, thermospheric measurements presented here should provide unambiguous vector wind information, and hence reduce the need to supplement observations with information obtained from models of the neutral atmosphere, or with estimates of neutral parameters derived from ionospheric measurements. These new data can also test the assumptions used in models and in ion-neutral interactions. The FPIs are located close to the 3 radars of the EISCAT configuration in northern Scandinavia, which is a region well covered by a network of complementary instruments. These provide a larger scale context within which to interpret our observations of mesoscale variations on the scales of tens of kilometres spatially and minutes temporally. Initial studies indicate that the thermosphere is more dynamic and responsive to ionospheric forcing than expected. Calculations using the tristatic volume measurements show that the magnitude of the neutral wind dynamo contribution was on average 29% of Joule heating during the first night of observation. At times it either enhanced or reduced the effective electric field by up to several tens of percent. The tristatic experiment also presents the first validation of absolute temperature measurements from a common

  9. Characterization of Leucaena (Leucaena leucephala) oil by direct analysis in real time (DART) ion source and gas chromatography

    International Nuclear Information System (INIS)

    Alam, M.; Alandis, N.M.; Sharmin, E.; Ahmad, N.; Alrayes, B.F.; Ali, D.

    2017-01-01

    For the first time, we report the characterization of triacylglycerols and fatty acids in Leucaena (Leucaena leucephala) oil [LUCO], an unexplored nontraditional non-medicinal plant belonging to the family Fabaceae. LUCO was converted to fatty acid methyl esters (FAMEs). We analyzed the triacylglycerols (TAGs) of pure LUCO and their FAMEs by time-of-flight mass spectrometry (TOF-MS) followed by multivariate analysis for discrimination among the FAMEs. Our investigations for the analysis of LUCO samples represent noble features of glycerides. A new type of ion source, coupled with high-resolution TOF-MS was applied for the comprehensive analysis of triacylglycerols. The composition of fatty acid based LUCO oil was studied using Gas Chromatography (GC-FID). The major fatty acid components of LUCO oil are linoleic acid (52.08%) oleic acid (21.26%), palmitic acid (7.91%) and stearic acid (6.01%). A metal analysis in LUCO was done by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The structural elucidation and thermal stability of LUCO were studied by FT-IR, 1H NMR, 13C NMR spectroscopic techniques and TGA-DSC, respectively. We also measured the cytotoxicity of LUCO [es

  10. High-performance ion mobility spectrometry with direct electrospray ionization (ESI-HPIMS) for the detection of additives and contaminants in food

    Energy Technology Data Exchange (ETDEWEB)

    Midey, Anthony J., E-mail: anthony.midey@excellims.com; Camacho, Amanda; Sampathkumaran, Jayanthi; Krueger, Clinton A.; Osgood, Mark A.; Wu, Ching

    2013-12-04

    Graphical abstract: -- Highlights: •A new ESI source was built for direct ionization from syringe. •Phthalates, food dyes, and sweeteners detected with high-performance IMS. •Phthalates directly detected in cola, soy bubble tea matrices with simple treatment. -- Abstract: High-performance ion mobility spectrometry (HPIMS) with an electrospray ionization (ESI) source detected a series of food contaminants and additive compounds identified as critical to monitoring the safety of food samples. These compounds included twelve phthalate plasticizers, legal and illegal food and cosmetic dyes, and artificial sweeteners that were all denoted as detection priorities. HPIMS separated and detected the range of compounds with a resolving power better than 60 in both positive and negative ion modes, comparable to the commonly used high-performance liquid chromatography (HPLC) methods, but with most acquisition times under a minute. The reduced mobilities, K{sub 0}, have been determined, as have the linear response ranges for ESI-HPIMS, which are 1.5–2 orders of magnitude for concentrations down to sub-ng μL{sup −1} levels. At least one unique mobility peak was seen for two subsets of the phthalates grouped by the country where they were banned. Furthermore, ESI-HPIMS successfully detected low nanogram levels of a phthalate at up to 30 times lower concentration than international detection levels in both a cola matrix and a soy-based bubble tea beverage using only a simplified sample treatment. A newly developed direct ESI source (Directspray) was combined with HPIMS to detect food-grade dyes and industrial dye adulterants, as well as the sweeteners sodium saccharin and sodium cyclamate, with the same good performance as with the phthalates. However, the Directspray method eliminated sources of carryover and decreased the time between sample runs. Limits-of-detection (LOD) for the analyte standards were estimated to be sub-ng μL{sup −1} levels without extensive

  11. High-performance ion mobility spectrometry with direct electrospray ionization (ESI-HPIMS) for the detection of additives and contaminants in food

    International Nuclear Information System (INIS)

    Midey, Anthony J.; Camacho, Amanda; Sampathkumaran, Jayanthi; Krueger, Clinton A.; Osgood, Mark A.; Wu, Ching

    2013-01-01

    Graphical abstract: -- Highlights: •A new ESI source was built for direct ionization from syringe. •Phthalates, food dyes, and sweeteners detected with high-performance IMS. •Phthalates directly detected in cola, soy bubble tea matrices with simple treatment. -- Abstract: High-performance ion mobility spectrometry (HPIMS) with an electrospray ionization (ESI) source detected a series of food contaminants and additive compounds identified as critical to monitoring the safety of food samples. These compounds included twelve phthalate plasticizers, legal and illegal food and cosmetic dyes, and artificial sweeteners that were all denoted as detection priorities. HPIMS separated and detected the range of compounds with a resolving power better than 60 in both positive and negative ion modes, comparable to the commonly used high-performance liquid chromatography (HPLC) methods, but with most acquisition times under a minute. The reduced mobilities, K 0 , have been determined, as have the linear response ranges for ESI-HPIMS, which are 1.5–2 orders of magnitude for concentrations down to sub-ng μL −1 levels. At least one unique mobility peak was seen for two subsets of the phthalates grouped by the country where they were banned. Furthermore, ESI-HPIMS successfully detected low nanogram levels of a phthalate at up to 30 times lower concentration than international detection levels in both a cola matrix and a soy-based bubble tea beverage using only a simplified sample treatment. A newly developed direct ESI source (Directspray) was combined with HPIMS to detect food-grade dyes and industrial dye adulterants, as well as the sweeteners sodium saccharin and sodium cyclamate, with the same good performance as with the phthalates. However, the Directspray method eliminated sources of carryover and decreased the time between sample runs. Limits-of-detection (LOD) for the analyte standards were estimated to be sub-ng μL −1 levels without extensive sample handling

  12. Parton energy loss in heavy-ion collisions via direct-photon and charged-particle Azimuthal Correlations

    NARCIS (Netherlands)

    Abelev, B.I.; Benedosso, F.; Braidot, E|info:eu-repo/dai/nl/304840874; Mischke, A.|info:eu-repo/dai/nl/325781435; Peitzmann, T.|info:eu-repo/dai/nl/304833959; Russcher, M.J.|info:eu-repo/dai/nl/304847844

    2010-01-01

    Charged-particle spectra associated with direct photon (γdir ) and π0 are measured in p+p and Au+Au collisions at center-of-mass energy √sNN=200 GeV with the STAR detector at RHIC. A hower-shape analysis is used to partially discriminate between γdir and π0. Assuming no associated charged particles

  13. Direct and Sensitive Detection of CWA Simulants by Active Capillary Plasma Ionization Coupled to a Handheld Ion Trap Mass Spectrometer

    Science.gov (United States)

    Wolf, Jan-Christoph; Etter, Raphael; Schaer, Martin; Siegenthaler, Peter; Zenobi, Renato

    2016-07-01

    An active capillary plasma ionization (ACI) source was coupled to a handheld mass spectrometer (Mini 10.5; Aston Labs, West Lafayette, IN, USA) and applied to the direct gas-phase detection and quantification of chemical warfare agent (CWA) related chemicals. Complementing the discontinuous atmospheric pressure interface (DAPI) of the Mini 10.5 mass spectrometer with an additional membrane pump, a quasi-continuous sample introduction through the ACI source was achieved. Nerve agent simulants (three dialkyl alkylphosphonates, a dialkyl phosporamidate, and the pesticide dichlorvos) were detected at low gas-phase concentrations with limits of detection ranging from 1.0 μg/m3 to 6.3 μg/m3. Our results demonstrate a sensitivity enhancement for portable MS-instrumentation by using an ACI source, enabling direct, quantitative measurements of volatile organic compounds. Due to its high sensitivity, selectivity, low power consumption (<80 W) and weight (<13 kg), this instrumentation has the potential for direct on-site CWA detection as required by military or civil protection.

  14. Direct Analysis of Metal Ions in Solutions with High Salt Concentrations by Total Reflection X-ray Fluorescence.

    Science.gov (United States)

    Regadío, Mercedes; Riaño, Sofía; Binnemans, Koen; Vander Hoogerstraete, Tom

    2017-04-18

    Total reflection X-ray fluorescence (TXRF) is becoming more and more popular for elemental analysis in academia and industry. However, simplification of the procedures for analyzing samples with complex compositions and residual matrix effects is still needed. In this work, the effect of an inorganic (CaCl 2 ) and an organic (tetraalkylphosphonium chloride) matrix on metals quantification by TXRF was investigated for liquid samples. The samples were spiked with up to 20 metals at concentrations ranging from 3 to 50 mg L -1 per element, including elements with spectral peaks near the peaks of the matrix elements or near the Raleigh and Compton scattering peaks of the X-ray source (molybdenum anode). The recovery rate (RR) and the relative standard deviation (RSD) were calculated to express the accuracy and the precision of the measured element concentrations. In samples with no matrix effects, good RRs are obtained regardless of the internal standard selected. However, in samples with moderate matrix content, the use of an optimum internal standard (OIS) at a concentration close to that of the analyte significantly improved the quantitative analysis. In samples with high concentrations of inorganic ions, using a Triton X-100 aqueous solution to dilute the sample during the internal standardization resulted in better RRs and lower RSDs compared to using only water. In samples with a high concentration of organic material, pure ethanol gave slightly better results than when a Triton X-100-ethanol solution was used for dilution. Compared to previous methods reported in the literature, the new sample-preparation method gave better accuracy, precision, and sensitivity for the elements tested. Sample dilution with an OIS and the surfactant Triton X-100 (inorganic media) or ethanol (organic media) is recommended for fast routine elemental determination in matrix containing samples, as it does not require special equipment, experimentally derived case-dependent mathematical

  15. CONGENITAL ORBITAL TERATOMA

    African Journals Online (AJOL)

    was done without contrast and 3mm/5mm/10mm slices were obtained to cover the orbit, skull base and brain. The findings included a soft tissue mass arising from the orbit. The left eye ball was extra orbital. There was no defect .... love's Short Practice of Surgery. 7 Edition,. Levis London, 1997; 45-64. 2. Orbital tumor Part 1, ...

  16. Geostationary orbit capacity study

    Science.gov (United States)

    Hansell, P. S.; Norris, P.; Walton, R.

    1982-04-01

    Factors influencing the communications satellite capacity of the geostationary orbit were analyzed to derive an interference model of the orbit environment. Comparison of the total orbit arc length required by each proposed planning method or by using different technology developments indicates that the orbit arc of most interest to Western Europe will not be saturated by the year 2000. The orbit arc occupied in the year 2000 by the satellites in the West European arc of interest can be approximately halved by using digital modulation techniques for TV program transfers which use FM at present, or by adopting an orbital planning method which assigns FM TV services to predefined orbit or spectrum segments.

  17. Radiovolumetry of the orbit

    International Nuclear Information System (INIS)

    Abujamra, S.

    1983-01-01

    The authors present a method called ''Radiovolumetry of the orbit'' that permits the evaluation of the orbital volume from anteroposterior skull X-Rays (CALDWELL 30 0 position). The research was based in the determination of the orbital volume with lead spheres, in 1010 orbits of 505 dry skulls of Anatomy Museums. After the dry skulls was X-rayed six frontal orbital diameters were made, with care to correct the radiographic amplification. PEARSON correlation coeficient test was applied between the mean orbital diameter and the orbital volume. The result was r = 0,8 with P [pt

  18. Direct detection of ammonium ion by means of oxygen electrocatalysis at a copper-polyaniline composite on a screen-printed electrode

    International Nuclear Information System (INIS)

    Zhybak, Mykhailo T.; Vagin, Mikhail Yu.; Beni, Valerio; Liu, Xianjie; Turner, Anthony P. F.; Dempsey, Eithne; Korpan, Yaroslav I.

    2016-01-01

    We describe a composite material for use in electrochemical oxygen reduction. A screen-printed electrode (SPE) was consecutively modified with electrodeposited copper, a Nafion membrane and electropolymerized polyaniline (PANi) to give an electrocatalytic composite of type PANi/Nafion/Cu 2 O/SPE that displays good electrical conductivity at neutral pH values. It is found that the presence of ammonia causes complex formation with Cu(I), and this causes electroreduction of oxygen to result in an increased cathodic current. The finding was applied to the quantification of ammonium ions in the 1 to 1000 μM concentration range by amperometry at −0.45 V (vs. Ag/AgCl). This Faradaic phenomenon offers the advantage of direct voltammetric detection, one of the lowest known limits of detection (0.5 μM), and high sensitivity (250 mA∙M −1 ∙cm −2 ). It was applied to the determination of ammonium ion in human serum where it compared well with the photometric routine approach for clinical analysis using glutamate dehydrogenase. (author)

  19. Measurements of isomeric yield ratios of fission products from proton-induced fission on natU and 232Th via direct ion counting

    Directory of Open Access Journals (Sweden)

    Rakopoulos Vasileios

    2017-01-01

    Full Text Available Independent isomeric yield ratios (IYR of 81Ge, 96Y, 97Y, 97Nb, 128Sn and 130Sn have been determined in the 25 MeV proton-induced fission of natU and 232Th. The measurements were performed at the Ion Guide Isotope Separator On-Line (IGISOL facility at the University of Jyväskylä. A direct ion counting measurement of the isomeric fission yield ratios was accomplished for the first time, registering the fission products in less than a second after their production. In addition, the IYRs of natU were measured by means of γ-spectroscopy in order to verify the consistency of the recently upgraded experimental setup. From the obtained results, indications of a dependence of the production rate on the fissioning system can be noticed. These data were compared with data available in the literature, whenever possible. Using the TALYS code and the experimentally obtained IYRs, we also deduced the average angular momentum of the fission fragments after scission.

  20. The rapid and direct determination of ATPase activity by ion exchange chromatography and the application to the activity of heat shock protein-90.

    Science.gov (United States)

    Bartolini, Manuela; Wainer, Irving W; Bertucci, Carlo; Andrisano, Vincenza

    2013-01-25

    Adenosine nucleotides are involved as substrates or co-factors in several biochemical reactions, catalyzed by enzymes, which modulate energy production, signal transduction and cell proliferation. We here report the development and optimization of an ion exchange liquid chromatography (LC) method for the determination of ATP, ADP and AMP. This method is specifically aimed at the determination of the ATP-ase activity of human heat shock protein 90 (Hsp90), a molecular chaperone that has emerged as target enzyme in cancer therapy. Separation of the three nucleotides was achieved in a 15-min run by using a disk shaped monolithic ethylene diamine stationary phase of small dimensions (2mm×6mm i.d.), under a three-solvent gradient elution mode and UV detection at 256nm. The described direct LC method resulted highly specific as a consequence of the baseline separation of the three adenosine nucleotides and could be applied to the determination of the enzymatic activity of ADP/ATP generating or consuming enzymes (such as kinases). Furthermore, comparison of the LOD and LOQ values of the LC method with those obtained with the malachite green assay, which is one of the most used indirect screening methodologies for ATP-ase activity, showed that the LC method has a similar range of application without presenting the drawbacks related to contamination by inorganic phosphate ions and glycerol, which are present in Hsp90 commercial samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Directed flow in relativistic heavy-ion collisions within the PHSD transport approach and 3FD hydrodynamical model

    Science.gov (United States)

    Konchakovski, V. P.; Cassing, W.; Ivanov, Y. B.; Toneev, V. D.

    2015-05-01

    We analyze recent STAR data for the directed flow of protons, antiprotons and charged pions obtained within the beam energy scan program within the Parton-Hadron-String- Dynamics (PHSD) transport model and the 3-Fluid hydroDynamics (3FD) approach. We clarify the role of partonic degrees of freedom in the kinetic PHSD approach. The PHSD results, simulating a partonic phase and its coexistence with a hadronic one, are roughly consistent with data. The hydrodynamic results are obtained for two EoS, a pure hadronic EoS and an EoS with a crossover type transition. The latter case is favored by the STAR experimental data. Special attention is paid to the description of antiproton directed flow based on the balance of pp\\bar annihilation and the inverse processes for Np\\bar pair creation from multi-meson interactions. Generally, a semi-qualitative agreement between the measured data and model results supports the idea of a crossover type quark-hadron transition which softens the nuclear EoS.

  2. Range finding of Alfvén oscillations and direction finding of ion-cyclotron waves by using the ground-based ULF finder

    Directory of Open Access Journals (Sweden)

    A. Guglielmi

    Full Text Available A new approach to the problem of direction and distance finding of magnetospheric ULF oscillations is described. It is based on additional information about the structure of geoelectromagnetic field at the Earth's surface which is contained in the known relations of the theory of magnetovariation and magnetotelluric sounding. This allows us to widen the range of diagnostic tools by using observations of Alfvén oscillations in the Pc 3–5 frequency band and the ion-cyclotron waves in the Pc 1 frequency band. Preliminary results of the remote sensing of the magnetosphere at low-latitudes using the MHD ranger technique are presented. The prospects for remote sensing of the plasmapause position are discussed.

  3. Effects of focused ion beam milling on the compressive behavior of directionally solidified micro-pillars and the nanoindentation response of an electro-polished surface

    International Nuclear Information System (INIS)

    Shim, Sang Hoon; Bei, Hongbin; Miller, Michael K; Pharr, George Mathews; George, Easo P

    2009-01-01

    Focused ion beam (FIB) milling is the typical way in which micro-pillars are fabricated to study small-scale plasticity and size effects in uniaxial compression. However, FIB milling can introduce defects into the milled pillars. To investigate the effects of FIB damage on mechanical behavior, we tested Mo-alloy micro-pillars that were FIB milled following directional solidification, and compared their compressive response to pillars that were not FIB milled. We also FIB milled at glancing incidence a Mo-alloy single-crystal surface, and compared its nanoindentation response to an electro-polished surface of the same crystal. Consequences for the interpretation of data obtained from FIB milled micro-pillars are discussed

  4. Ion-beam-spurted dimethyl-sulfate-doped PEDOT:PSS composite-layer-aligning liquid crystal with low residual direct-current voltage

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang; Lee, Ju Hwan; Seo, Dae-Shik, E-mail: dsseo@yonsei.ac.kr [Information Display Device Laboratory, Department of Electrical and Electronic Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Li, Xiang-Dan, E-mail: lixiangdan@mail.scuec.edu.cn [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, South-Central University for Nationalities, 182 Minyuan Road, Hongshan District, Wuhan 430-074 (China)

    2016-09-05

    Thin ion-beam (IB)-spurted dimethyl sulfate/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (DMS/PEDOT:PSS) layers with improved electro-optic performance are presented for aligning liquid crystals. IB spurting is effective for enhancing the conductivity of such layers, as well as the anchoring energy of the liquid crystals sandwiched between them. Compared with a commercial twisted-nematic cell assembled with polyimide alignment layers, the same cell assembled with 3.0-keV IB-spurted DMS/PEDOT:PSS alignment layers shows a 38% faster switching and a 93% lower residual direct current. The improved electro-optic performance here is likely due to the enhanced electric field effect and the charge-releasing ability of thin IB-spurted DMS/PEDOT:PSS layers.

  5. Direct Infusion Electrospray Ionization - Ion Mobility - High Resolution Mass Spectrometry (DIESI-IM-HRMS) for Rapid Characterization of Potential Bioprocess Streams

    Science.gov (United States)

    Munisamy, Sharon M.; Chambliss, C. Kevin; Becker, Christopher

    2012-07-01

    Direct infusion electrospray ionization - ion mobility - high resolution mass spectrometry (DIESI-IM-HRMS) has been utilized as a rapid technique for the characterization of total molecular composition in "whole-sample" biomass hydrolysates and extracts. IM-HRMS data reveal a broad molecular weight distribution of sample components (up to 1100 m/z) and provide trendline isolation of feedstock components from those introduced "in process." Chemical formulas were obtained from HRMS exact mass measurements (with typical mass error less than 5 ppm) and were consistent with structural carbohydrates and other lignocellulosic degradation products. Analyte assignments are supported via IM-MS collision-cross-section measurements and trendline analysis (e.g., all carbohydrate oligomers identified in a corn stover hydrolysate were found to fall within 6 % of an average trendline). These data represent the first report of collision cross sections for several negatively charged carbohydrates and other acidic species occurring natively in biomass hydrolysates.

  6. Implementation of Theeuropeanwater Framework Directive In France: New Challenges For River Basin Organisat Ion, Planning and Participation

    Science.gov (United States)

    Allain, S.

    The European Water Framework Directive (2000/60/EC) establishes a system of participatory river basin planning for national and international basins. The French institutional framework for water management is already very close to this system: the 1964 Water Law actually set up basin bodies, the Agences de l'Eau ("Water Agencies"), at the level of large river basins, and multipartite basin commissions, the Comités de Bassin ("River Basin Authorities"), in order to monitor the Agences de l'Eau's policies; besides, the 1992 Water Law created a planning procedure at this level, the Schéma Directeur d'Aménagement et de Gestion des Eaux (SDAGE : "General Water Management Plan"), aiming to determine general orientations for the management of water resources and having to be defined by the Comités de Bassin. At first glance therefore, the implementation of the European Water Framework Directive should not raise a lot of problems in France. However, a quick analysis of the current situation shows that it is not so obvious : if the French Water Policy set up two basin organisations, neither of them deals concretely with the management of the water resources, and the implementation of water management plans depends on many stakeholders; the SDAGE itself only partially meets the demands of the Directive, regarding e. g. the economic analysis; finally, in spite of the creation of multipartite basin commissions, the public participation is very restricted. Such an analysis leads to pay more attention to the relations to establish between organisation, planning and participation at the level of large river basins. An analysis of other elements of the French institutional framework can help us in this way : another planning procedure was actually created by the 1992 Water Law, the Schéma d'Aménagement et de Gestion des Eaux (SAGE : "Water Management Plan"), aiming to fix general objectives to manage the water resources at the level of small river basins, and having to be

  7. Restricted accessed nanoparticles for direct magnetic solid phase extraction of trace metal ions from human fluids followed by inductively coupled plasma mass spectrometry detection.

    Science.gov (United States)

    Yan, Ping; He, Man; Chen, Beibei; Hu, Bin

    2015-06-21

    Herein, restricted accessed magnetic nanoparticles were synthesized by self-assembly of a non-ionic surfactant (Tween-20) onto the 4-(2-pyridylazo)resorcinol (PAR) functionalized magnetic nanoparticles (MNPs). A series of analytical techniques were employed for the characterization of the as-prepared restricted accessed Fe3O4@SiO2@PAR, and it was found that the as-prepared restricted accessed Fe3O4@SiO2@PAR nanoparticles have a porous structure with a BET surface area of around 99.4 m(2) g(-1), an average pore size of about 6.14 nm and a pore volume of 0.47 cm(3) g(-1). Besides, the prepared restricted accessed Fe3O4@SiO2@PAR showed good size exclusion properties toward proteins, providing application potential for the direct analysis of biological samples. Based on this, a novel method of restricted accessed magnetic solid phase extraction (MSPE) combined with inductively coupled plasma-mass spectrometry (ICP-MS) was developed for the direct determination of trace metal ions in human fluids. The parameters affecting the extraction of the target metals by MSPE were studied and the optimized conditions were established. Under the optimum conditions, the adsorption capacity of Cr(III), Cd(II), La(III), Nd(III) and Pb(II) on the as-prepared restricted accessed Fe3O4@SiO2@PAR was 62.9, 56.6, 33.7, 36.9 and 43.3 mg g(-1), respectively. With an enrichment factor of 30, the limits of detection for Cr(III), Cd(II), La(III), Nd(III) and Pb(II) were as low as 11.9, 0.8, 0.7, 1.6 and 4.1 ng L(-1), and the relative standard deviations were 7.6, 8.7, 8.4, 8.1 and 5.0 (C(Cr, Pb) = 0.05 μg L(-1), C(Cd, La) = 0.005 μg L(-1), C(Nd) = 0.01 μg L(-1), n = 7), respectively. The developed method was successfully applied for the direct analysis of free metal ions in human urine and serum samples, and has the advantages of good anti-interference ability, high sensitivity and exhibits great application potential in the direct analysis of trace metals in biological fluids.

  8. Orbital computed tomography: technical aspects

    International Nuclear Information System (INIS)

    Beck, T.J.; Rosenbaum, A.E.; Miller, N.R.

    1982-01-01

    Computed tomographic scanning has revolutionized the diagnosis and management of orbital disease. The best use of this methodology requires knowledge of the principles and appropriate attention to scanning protocols. Computed tomographic scanning of the orbit is a demanding technique requiring thin sections through planes precisely positioned from the topographical anatomy. Ideally, orbital CT should include both transverse axial and coronal sections: The pathological condition and its plane of growth will influence the selection of the optimal plane or section. Coronal sections may be obtained either directly or indirectly by computer reconstruction from contiguous transverse images. Sagittal or oblique sections or both also are useful and may be obtained directly or indirectly. Difficulty in patient positioning may preclude direct sagittal imaging, however. The use of intravenous contrast enhancement is not necessary as a routine technique unless a mass is identified or suspected. Where surgical resection or biopsy of a space-occupying lesion is contemplated, contrast enhancement can be valuable in assessing relative vascularity and aiding diagnostic specificity. It should be continually emphasized that CT is a powerful technology which, in orbital diagnosis, produces the highest yield when clinician and radiologist collaborate in the radiodiagnostic workup. The clinical information supplied by the referring ophthalmologist is used by the radiologist both in the selection of the appropriate techniques for investigation and in striving to achieve the most specific conclusion

  9. NMR study of thallium(I) ions in molten binary mixtures of nitrates and chlorides

    International Nuclear Information System (INIS)

    Nakamura, Yoshio; Kitazawa, Yukiharu; Shimoji, Mitsuo; Shimokawa, Shigezo.

    1983-01-01

    The chemical shifts of 205 Tl NMR in molten binary mixtures of nitrates and those of chlorides have been measured as a function of composition and temperature. The shifts increase in the diamagnetic direction with decreasing the size of foreign cations and increase in the paramagnetic direction with increasing temperature. These results are interpreted by changes in the overlap of orbitals of the Tl + ion and the anion, which depend upon composition and temperature. (author)

  10. Preseptal Cellulitis, Orbital Cellulitis, Orbital Abscess

    Directory of Open Access Journals (Sweden)

    Rana Altan Yaycıoğlu

    2012-12-01

    Full Text Available Patients with orbital infections present to our clinic usually with unilateral pain, hyperemia, and edema of the eyelids. The differentiation between preseptal and orbital cellulitis is utmost important in that the second requires hospitalization. Since in orbital cellulitis, the tissues posterior to the orbital septum are involved, signs such as conjunctival chemosis, limited eye movement, decreased vision, as well as afferent pupil defect secondary to optic nerve involvement may also be observed. Prompt intravenous antibiotic treatment should be started, and surgical drainage may be performed if patient shows failure to improve in 48 hours despite optimal management. Without treatment, the clinical course may progress to subperiosteal or orbital abscess, and even to cavernous sinus thrombosis. (Turk J Ophthalmol 2012; 42: Supplement 52-6

  11. Microbiology of pediatric orbital cellulitis.

    Science.gov (United States)

    McKinley, Steven H; Yen, Michael T; Miller, Aaron M; Yen, Kimberly G

    2007-10-01

    To evaluate the microbiology of pediatric orbital cellulitis associated with sinusitis. Retrospective review of medical records of pediatric patients treated for orbital cellulitis. All pediatric patients treated for orbital cellulitis associated with sinusitis at Texas Children's Hospital between December 1, 2001 and September 30, 2005 were reviewed. Data collected included patient age, history, microbiology results, and surgical intervention. Thirty-eight cases were identified. Fifteen cases required medical management, whereas 23 patients received a combination of medical and surgical intervention. Three patients had multiple surgical procedures performed. Of the procedures performed, four were sinus irrigation, 12 were sinusotomy and drainage, nine were orbitotomy with drainage of abscess, and one was craniotomy with drainage of abscess. Surgical aspirate specimens yielded a higher positive culture result rate with 9/9 of orbital abscesses and 13/16 of sinus aspirates demonstrating a positive yield. Two of the 27 blood cultures had a positive yield. Staphylococcus species was the most common organism isolated. Methicillin-resistant S. aureus (MRSA) represented 73% of S. aureus isolates. Streptococcus species was the next most common pathogen. Three cultures yielded Haemophilus species with one being positive for H. influenzae. Organisms responsible for causing pediatric orbital cellulitis are evolving, with Staphylococcus followed by Streptococcus species being the most common pathogens. The occurrence of MRSA in pediatric orbital cellulitis is increasing, and empiric antimicrobial therapy should be directed against these organisms if they are prevalent in the community. Sinus and orbital abscess aspirates yielded the greatest number of positive cultures, though these invasive surgical procedures should be performed only when clinically indicated.

  12. Orbital ordering in CaV2O4: A neutron scattering study

    Science.gov (United States)

    Pieper, Oliver; Lake, B.; Daoud-Aladine, A.; Reehuis, M.; Perring, T.; Enderle, M.; Rule, K.; Prokes, K.; Klemke, B.; Kiefer, K.; Niazi, A.; Yan, J. Q.; Johnston, D. C.; Honecker, A.

    2010-03-01

    CaV2O4 is a quasi-one dimensional spin-1 Heisenberg antiferromagnet. The magnetism arises from the partially filled t2g-levels of the V^3+-ions, which in addition give an orbital degree of freedom to the system. In contrast to the isovalent vanadium spinel compounds, the low dimensionality in CaV2O4 already arises from the crystal structure. It contains weakly coupled double-chains of edge-sharing VO6 octahedra, where the particular octahedral staggering creates a zigzag-like arrangement of the vanadium ions. This in return gives rise to strong magnetic direct exchange interactions between nearest and next nearest neighbor vanadium ions and to geometrical frustration. However, the strength of the exchange interactions is strongly influenced by the particular occupation of the t2g-orbitals. Depending on the type and degree of octahedral distortion, the system can be interpreted as a frustrated Haldane chain or a spin-1 ladder. Here we use single crystal neutron diffraction and neutron spectroscopy to determine the spin structure as well as the complex excitation spectrum of CaV2O4. The results are analyzed theoretically and from this the leading exchange paths are deduced and discussed in terms of orbital ordering.

  13. Drug delivery system for an anticancer agent, chlorogenate-Zn/Al-layered double hydroxide nanohybrid synthesised using direct co-precipitation and ion exchange methods

    Science.gov (United States)

    Barahuie, Farahnaz; Hussein, Mohd Zobir; Arulselvan, Palanisamy; Fakurazi, Sharida; Zainal, Zulkarnain

    2014-09-01

    A nano-structured drug-inorganic clay hybrid involving an active anticancer compound, which is chlorogenic acid (CA) intercalated into Zn/Al-layered double hydroxide, has been assembled via ion-exchange and co-precipitation methods to form a nanohybrid CZAE (a chlorogenic acid-Zn/Al nanohybrid synthesised using an ion-exchange method) and CZAC (a chlorogenic acid-Zn/Al nanohybrid synthesised using a direct method), respectively. The X-ray diffraction (XRD) results confirmed that the CA-LDH had a hybrid structure in which the anionic chlorogenate is arranged between the interlayers as a horizontal monolayer at 90 and 20° angles from the x axis for CZAE and CZAC, respectively. Both nanohybrids have the properties of mesoporous materials. The high loading percentage of chlorogenic acid (approximately 43.2% for CZAE and 45.3% for CZAC) with basal spacings of 11.7 and 12.6 Å for CZAE and CZAC, respectively, corroborates the successful intercalation of chlorogenic acid into the interlayer gallery of layered double hydroxides. Free chlorogenic acid and the synthesised nanocomposites (CZAE, CZAC) were assessed for their cytotoxicity against various cancer cells. The Fourier transform infrared data supported the formation of both nanohybrids, and a thermal analysis showed that the nanohybrids are more thermally stable than their counterparts. The chlorogenate shows a sustained release, and the release rate of chlorogenate from CZAE and CZAC nanohybrids at pH 7.4 is remarkably lower than that at pH 4.8 due to their different release mechanisms. The release rate of chlorogenate from both nanohybrids can be described as pseudo-second order. The present investigation revealed the potential of the nanohybrids to enhance the in vitro anti-tumour effect of chlorogenic acid in liver and lung cancer cells in vitro.

  14. Drug delivery system for an anticancer agent, chlorogenate-Zn/Al-layered double hydroxide nanohybrid synthesised using direct co-precipitation and ion exchange methods

    Energy Technology Data Exchange (ETDEWEB)

    Barahuie, Farahnaz [Materials Synthesis and Characterization Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Hussein, Mohd Zobir, E-mail: mzobir@putra.upm.edu.my [Materials Synthesis and Characterization Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Arulselvan, Palanisamy [Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Fakurazi, Sharida [Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Zainal, Zulkarnain [Materials Synthesis and Characterization Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia)

    2014-09-15

    A nano-structured drug-inorganic clay hybrid involving an active anticancer compound, which is chlorogenic acid (CA) intercalated into Zn/Al-layered double hydroxide, has been assembled via ion-exchange and co-precipitation methods to form a nanohybrid CZAE (a chlorogenic acid-Zn/Al nanohybrid synthesised using an ion-exchange method) and CZAC (a chlorogenic acid-Zn/Al nanohybrid synthesised using a direct method), respectively. The X-ray diffraction (XRD) results confirmed that the CA-LDH had a hybrid structure in which the anionic chlorogenate is arranged between the interlayers as a horizontal monolayer at 90 and 20° angles from the x axis for CZAE and CZAC, respectively. Both nanohybrids have the properties of mesoporous materials. The high loading percentage of chlorogenic acid (approximately 43.2% for CZAE and 45.3% for CZAC) with basal spacings of 11.7 and 12.6 Å for CZAE and CZAC, respectively, corroborates the successful intercalation of chlorogenic acid into the interlayer gallery of layered double hydroxides. Free chlorogenic acid and the synthesised nanocomposites (CZAE, CZAC) were assessed for their cytotoxicity against various cancer cells. The Fourier transform infrared data supported the formation of both nanohybrids, and a thermal analysis showed that the nanohybrids are more thermally stable than their counterparts. The chlorogenate shows a sustained release, and the release rate of chlorogenate from CZAE and CZAC nanohybrids at pH 7.4 is remarkably lower than that at pH 4.8 due to their different release mechanisms. The release rate of chlorogenate from both nanohybrids can be described as pseudo-second order. The present investigation revealed the potential of the nanohybrids to enhance the in vitro anti-tumour effect of chlorogenic acid in liver and lung cancer cells in vitro. - Highlights: • We intercalated chlorogenic into Zn/Al-layered double hydroxide by ion-exchange and coprecipitation methods. • The two methods gave nanocomposites

  15. Lunar Orbiter Photo Gallery

    Data.gov (United States)

    National Aeronautics and Space Administration — The Lunar Orbiter Photo Gallery is an extensive collection of over 2,600 high- and moderate-resolution photographs produced by all five of the Lunar Orbiter...

  16. ASC Champ Orbit Model

    DEFF Research Database (Denmark)

    Riis, Troels; Jørgensen, John Leif

    1999-01-01

    This documents describes a test of the implementation of the ASC orbit model for the Champ satellite.......This documents describes a test of the implementation of the ASC orbit model for the Champ satellite....

  17. Direct evidence of reactive ion etching induced damages in Ge{sub 2}Sb{sub 2}Te{sub 5} based on different halogen plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Li, Juntao [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Microsystem Technology Laboratory, Microsystem & Terahertz Research Center, Sichuan Province 610200 (China); Xia, Yangyang [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100080 (China); Liu, Bo, E-mail: liubo@mail.sim.ac.cn [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Feng, Gaoming [United Lab, Semiconductor Manufacturing International Corporation, Shanghai 201203 (China); Song, Zhitang [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Gao, Dan; Xu, Zhen; Wang, Weiwei [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100080 (China); Chan, Yipeng [United Lab, Semiconductor Manufacturing International Corporation, Shanghai 201203 (China); Feng, Songlin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

    2016-08-15

    Highlights: • The results of SEM and AFM directly showed that the surface of Cl2 etched samples were roughest with a Ge deficient damaged layer. • The XPS of Te 3d revealed the electrons were transferred from chalcogenide to halogen and the highest halogenation was observed on CF4 etching GST films. • The sidewall of HBr etching GST is nearly vertical compared with others. • HBr is promising gas for GST etching in the fabrication of high-density memory devices. - Abstract: Chalcogenide glasses based on Ge-Te-Sb are processed using reactive ion etching (RIE) in the fabrication of phase change memory (PCM). These materials are known to be halogenated easily and apt to be damaged when exposed to halogen gas based plasmas which can cause severe halogenation-induced degradation. In this paper, we investigate the RIE induced damage of popular phase change material Ge{sub 2}Sb{sub 2}Te{sub 5} (GST) in different halogen based plasmas (CF{sub 4}, Cl{sub 2} and HBr) highly diluted by argon. After blanket etching, results of scanning electron microscopy and atomic force microscopy directly showed that the surface of Cl{sub 2} etched samples were roughest with a Ge deficient damaged layer. X-ray photoelectron spectroscopy was performed to investigate the chemical shift of constituent elements. Selected scans over the valence band peaks of Te 3d revealed that electrons were transferred from chalcogenide to halogen and the highest halogenation was observed on the GST etched by CF{sub 4}. The GST films masked with patterned TiN were also etched. High-resolution transmission electron microscopy and surface scan directly showed the line profile and the damaged layer. Almost vertical and smooth sidewall without damaged layer makes HBr a promising gas for GST etch in the fabrication of high-density memory devices.

  18. Assess the key physics that underpins high-hydro coupling-efficiency in NDCX-II experiments and high-gain heavy ion direct drive target designs using proven hydro codes like HYDRA

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, J. J.; Hay, M. J.; Logan, B. G.; Ng, S. F.; Perkins, L. J.; Veitzer, S.; Yu, S. S.

    2010-07-01

    The simulations provided in this milestone have solidified the theoretical underpinning of direct drive targets and also the ability to design experiments on NDCX II that will enhance our understanding of ion-beam hydrodynamic coupling, and thus be relevant to IFE. For the case of the IFE targets, we have studied hydro and implosion efficiency using HYDRA in ID, a starting point towards the goal of polar direct drive in geometry compatible with liquid wall chambers. Recent analysis of direct drive fusion energy targets using heavy ion beams has found high coupling efficiency of ion beam energy into implosion energy. However, to obtain optimal coupling, the ion energy must increase during the pulse in order to penetrate the outflowing ablated material, and deposit the energy close enough to the fuel so that the fuel achieves sufficient implosion velocity. We have computationally explored ID (radial) time dependent models of ion driven direct drive capsule implosions using the Arbitrary Lagrangian-Eulerian (ALE) code HYDRA, to help validate the theoretical analysis done so far, particularly exploring the effects of varying the ion energy and ion current over the course of the pulse. On NDCX II, experiments have been proposed to explore issues of ion penetration of the outflowing plasma over the course of the ion pulse. One possibility is to create a first pulse of ions that heats a planar target, and produces an outflow of material. A second pulse, {approx}10 ns after the first, of higher ion energy (and hence larger projected range) will interact with this outflow before reaching and further heating the target. We have investigated whether the change in range can be tailored to match the evolution of the ablation front. We have carried out simulations using the one-dimensional hydrodynamic code DISH and HYDRA to set parameters for this class of experiments. DISH was upgraded with an ion deposition algorithm, and we have carried out ID (planar) simulations. HYDRA was

  19. Traumatic transconjunctival orbital emphysema.

    OpenAIRE

    Stroh, E M; Finger, P T

    1990-01-01

    Orbital emphysema can be produced by trans-conjunctival migration of air from a high pressure airgun. In an industrial accident an 8 mm conjunctival laceration was produced in the superior fornix which acted as a portal of entry for air into the subconjunctival, subcutaneous, and retrobulbar spaces. Computed tomography revealed no evidence of orbital fracture and showed that traumatic orbital emphysema occurred without a broken orbital bone.

  20. Eye and orbital cavity

    International Nuclear Information System (INIS)

    Panfilova, G.V.; Koval', G.Yu.

    1984-01-01

    Radioanatomy of eyes and orbit is described. Diseases of the orbit (developmental anomalies, inflammatory diseases, lacrimal apparatus deseases, toxoplasmosis, tumors and cysts et al.), methods of foreign body localization in the eye are considered. Roentgenograms of the orbit and calculation table for foreign body localization in spherical eyes of dissimilar diameter are presented

  1. Idiopathic granulomatous orbital inflammation

    NARCIS (Netherlands)

    Mombaerts, I.; Schlingemann, R. O.; Goldschmeding, R.; Koornneef, L.

    1996-01-01

    PURPOSE: Granulomatous orbital inflammation may occur as an isolated condition of unknown origin. These idiopathic granulomatous lesions are believed to belong to the orbital pseudotumor group by some authors, whereas others consider them sarcoidosis limited to the orbit. The aim of this study is to

  2. Introducing Earth's Orbital Eccentricity

    Science.gov (United States)

    Oostra, Benjamin

    2015-01-01

    Most students know that planetary orbits, including Earth's, are elliptical; that is Kepler's first law, and it is found in many science textbooks. But quite a few are mistaken about the details, thinking that the orbit is very eccentric, or that this effect is somehow responsible for the seasons. In fact, the Earth's orbital eccentricity is…

  3. Ion source

    International Nuclear Information System (INIS)

    1979-01-01

    The ion source comprises a cylindrically shaped chamber with a longitudinal outlet slot formed therein and two uniform anode wires which extend along the length of the chamber in the middle region thereof and which are symmetrically introduced with respect to the length axis of the chamber and the outlet groove, characterised in that at each outer end of the outlet groove at a nearly null potential or direct potential is introduced a mask, whereby the lowest distance between the inner and outer ends of the mask is equivalent to the breadth of the ion beam emitted from the source. (G.C.)

  4. Fast ion loss and radial electric field in Wendelstein VII-Λ stellarator

    International Nuclear Information System (INIS)

    Itoh, K.; Sanuki, H.; Itoh, S.

    1991-10-01

    Theoretical model is developed to determine the radial electric field and the fast ion loss simultaneously in stellarators, and is applied to the Wendelstein VII-A stellarator. The predicted value of the radial electric field is more closer to experiments than the purely neoclassical calculation. The loss rate, which is determined simultaneously, is in the range of experimental observations. The partition of the injection energy by the bulk heating, direct orbit loss and shine through is estimated by using the self consistent electric field profile. The orbit loss become noticeable as the injection energy increases. The influence of the neutral particles is also studied. Neutral particles enhances the negative radial electric field, and reduces the direct orbit loss by the expense of the charge exchange loss. The impact of the increased radial electric field on the neoclassical ion thermal energy loss is compared to the direct loss of fast ions. The reduction of the neoclassical loss is much smaller than the orbit loss. (author)

  5. Forces charging the orbital floor after orbital trauma.

    Science.gov (United States)

    Birkenfeld, Falk; Steiner, Martin; Becker, Merlind Erika; Kern, Matthias; Wiltfang, Jörg; Lucius, Ralph; Becker, Stephan Thomas

    2012-07-01

    The objectives of this study were (i) to evaluate different fracture mechanisms for orbital floor fractures and (ii) to measure forces and displacement of intraorbital tissue after orbital traumata to predict the necessity of strength for reconstruction materials. Six fresh frozen human heads were used, and orbital floor defects in the right and left orbit were created by a direct impact of 3.0 J onto the globe and infraorbital rim, respectively. Orbital floor defect sizes and displacement were evaluated after a Le Fort I osteotomy. In addition, after reposition of the intraorbital tissue, forces and displacement were measured. The orbital floor defect sizes were 208.3 (SD, 33.4) mm(2) for globe impact and 221.8 (SD, 53.1) mm(2) for infraorbital impact. The intraorbital tissue displacement after the impact and before reposition was 5.6 (SD, 1.0) mm for globe impact and 2.8 (SD, 0.7) mm for infraorbital impact. After reposition, the displacement was 0.8 (SD, 0.5) mm and 1.1 (SD, 0.7) mm, respectively. The measured applied forces were 0.061 (SD, 0.014) N for globe impact and 0.066 (SD, 0.022) N for infraorbital impact. Different fracture-inductive mechanisms are not reflected by the pattern of the fracture. The forces needed after reposition are minimal (~0.07 N), which may explain the success of PDS foils [poly-(p-dioxanone)] and collagen membranes as reconstruction materials.

  6. Fusion-Enabled Pluto Orbiter and Lander

    Science.gov (United States)

    Thomas, Stephanie

    2017-01-01

    The Pluto orbiter mission proposed here is credible and exciting. The benefits to this and all outer-planet and interstellar-probe missions are difficult to overstate. The enabling technology, Direct Fusion Drive, is a unique fusion engine concept based on the Princeton Field-Reversed Configuration (PFRC) fusion reactor under development at the Princeton Plasma Physics Laboratory. The truly game-changing levels of thrust and power in a modestly sized package could integrate with our current launch infrastructure while radically expanding the science capability of these missions. During this Phase I effort, we made great strides in modeling the engine efficiency, thrust, and specific impulse and analyzing feasible trajectories. Based on 2D fluid modeling of the fusion reactors outer stratum, its scrape-off-layer (SOL), we estimate achieving 2.5 to 5 N of thrust for each megawatt of fusion power, reaching a specific impulse, Isp, of about 10,000 s. Supporting this model are particle-in-cell calculations of energy transfer from the fusion products to the SOL electrons. Subsequently, this energy is transferred to the ions as they expand through the magnetic nozzle and beyond. Our point solution for the Pluto mission now delivers 1000 kg of payload to Pluto orbit in 3.75 years using 7.5 N constant thrust. This could potentially be achieved with a single 1 MW engine. The departure spiral from Earth orbit and insertion spiral to Pluto orbit require only a small portion of the total delta-V. Departing from low Earth orbit reduces mission cost while increasing available mission mass. The payload includes a lander, which utilizes a standard green propellant engine for the landing sequence. The lander has about 4 square meters of solar panels mounted on a gimbal that allows it to track the orbiter, which beams 30 to 50 kW of power using a 1080 nm laser. Optical communication provides dramatically high data rates back to Earth. Our mass modeling investigations revealed that if

  7. Nontraumatic orbital roof encephalocele.

    Science.gov (United States)

    Hoang, Amber; Maugans, Todd; Ngo, Thang; Ikeda, Jamie

    2017-02-01

    Intraorbital meningoencephaloceles occur most commonly as a complication of traumatic orbital roof fractures. Nontraumatic congenital orbital meningoncephaloceles are very rare, with most secondary to destructive processes affecting the orbit and primary skull defects. Treatment for intraorbital meningoencephaloceles is surgical repair, involving the excision of herniated brain parenchyma and meninges and reconstruction of the osseous defect. Most congenital lesions present in infancy with obvious globe and orbital deformities; we report an orbital meningoencephalocele in a 3-year-old girl who presented with ptosis. Copyright © 2017 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  8. Electron capture by highly charged ions from surfaces and gases

    Energy Technology Data Exchange (ETDEWEB)

    Allen, F.

    2008-01-11

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar{sup 17+} and Ar{sup 18+} ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu{sup -1}, charge-selected and then decelerated down to 5 eVu{sup -1} for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar{sup 17+} and Ar{sup 18+} ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu{sup -1}, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar{sup 16+} and Xe{sup 44+} and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  9. Direct observation of defects and increased ion permeability of a membrane induced by structurally disordered Cu/Zn-superoxide dismutase aggregates.

    Directory of Open Access Journals (Sweden)

    Inhee Choi

    Full Text Available Interactions between protein aggregates and a cellular membrane have been strongly implicated in many protein conformational diseases. However, such interactions for the case of Cu/Zn superoxide dismutase (SOD1 protein, which is related to fatal neurodegenerative disorder amyotrophic lateral sclerosis (ALS, have not been explored yet. For the first time, we report the direct observation of defect formation and increased ion permeability of a membrane induced by SOD1 aggregates using a supported lipid bilayer and membrane patches of human embryonic kidney cells as model membranes. We observed that aggregated SOD1 significantly induced the formation of defects within lipid membranes and caused the perturbation of membrane permeability, based on surface plasmon resonance spectroscopy, atomic force microscopy and electrophysiology. In the case of apo SOD1 with an unfolded structure, we found that it bound to the lipid membrane surface and slightly perturbed membrane permeability, compared to other folded proteins (holo SOD1 and bovine serum albumin. The changes in membrane integrity and permeability were found to be strongly dependent on the type of proteins and the amount of aggregates present. We expect that the findings presented herein will advance our understanding of the pathway by which structurally disordered SOD1 aggregates exert toxicity in vivo.

  10. Direct observation of defects and increased ion permeability of a membrane induced by structurally disordered Cu/Zn-superoxide dismutase aggregates.

    Science.gov (United States)

    Choi, Inhee; Song, Hyeon Don; Lee, Suseung; Yang, Young In; Nam, Joo Hyun; Kim, Sung Joon; Sung, Jung-Joon; Kang, Taewook; Yi, Jongheop

    2011-01-01

    Interactions between protein aggregates and a cellular membrane have been strongly implicated in many protein conformational diseases. However, such interactions for the case of Cu/Zn superoxide dismutase (SOD1) protein, which is related to fatal neurodegenerative disorder amyotrophic lateral sclerosis (ALS), have not been explored yet. For the first time, we report the direct observation of defect formation and increased ion permeability of a membrane induced by SOD1 aggregates using a supported lipid bilayer and membrane patches of human embryonic kidney cells as model membranes. We observed that aggregated SOD1 significantly induced the formation of defects within lipid membranes and caused the perturbation of membrane permeability, based on surface plasmon resonance spectroscopy, atomic force microscopy and electrophysiology. In the case of apo SOD1 with an unfolded structure, we found that it bound to the lipid membrane surface and slightly perturbed membrane permeability, compared to other folded proteins (holo SOD1 and bovine serum albumin). The changes in membrane integrity and permeability were found to be strongly dependent on the type of proteins and the amount of aggregates present. We expect that the findings presented herein will advance our understanding of the pathway by which structurally disordered SOD1 aggregates exert toxicity in vivo. © 2011 Choi et al.

  11. Reactive ion etching challenges for half-pitch sub-10-nm line-and-space pattern fabrication using directed self-assembly lithography

    Science.gov (United States)

    Kasahara, Yusuke; Seino, Yuriko; Sato, Hironobu; Kubota, Hitoshi; Kanai, Hideki; Kihara, Naoko; Minegishi, Shinya; Miyagi, Ken; Tobana, Toshikatsu; Shiraishi, Masayuki; Kobayashi, Katsutoshi; Kodera, Katsuyoshi; Yamano, Hitoshi; Kawamonzen, Yoshiaki; Azuma, Tsukasa

    2016-03-01

    Directed self-assembly is a candidate process for sub-15-nm patterning applications. It will be necessary to develop the DSA process fully and consider process integration to adapt the DSA process for use in semiconductor manufacturing. We investigated the reactive ion etching (RIE) process for the fabrication of sub-10-nm metal wires using the DSA process and the process integration requirements for electrical yield verification. We evaluated the process using an organic high-chi block copolymer (BCP) with a lamellar structure. One critical issue during DSA pattern transfer involves the BCP bottom connection. The BCP bottom connections could be removed without BCP mask loss by using the optimum bias power and the optimum BCP film thickness. The sub-10-nm DSA line-and-space (L/S) patterns were successfully transferred to a SiO2 layer with sufficient film thickness for the fabrication of the metal wire. We also evaluated the overlay technique used in the process. The connect patterns and cut patterns were overlaid on 10-nm trenches fabricated by the DSA process.

  12. HPLC/ESI-quadrupole ion trap mass spectrometry for characterization and direct quantification of amphoteric and nonionic surfactants in aqueous samples

    Science.gov (United States)

    Levine, Lanfang H.; Garland, Jay L.; Johnson, Jodie V.

    2002-01-01

    An amphoteric (cocamidopropylbetaine, CAPB) and a nonionic (alcohol polyethoxylate, AE) surfactant were characterized by electrospray ionization quadrupole ion trap mass spectrometry (ESI-MS) as to their homologue distribution and ionization/fragmentation chemistry. Quantitative methods involving reversed-phase gradient HPLC and (+)ESI-MSn were developed to directly determine these surfactants in hydroponic plant growth medium that received simulated graywater. The predominant homologues, 12 C alkyl CAPB and 9 EO AE, were monitored to represent the total amount of the respective surfactants. The methods demonstrated dynamic linear ranges of 0.5-250 ng (r2 > 0.996) for CAPB and 8-560 ng (r2 > 0.998) for AE homologue mixture, corresponding to minimum quantification limits of 25 ppb CAPB and 0.4 ppm AE with 20-microL injections. This translated into an even lower limit for individual components due to the polydispersive nature of the surfactants. The procedure was successfully employed for the assessment of CAPB and AE biodegradation in a hydroponic plant growth system used as a graywater bioreactor.

  13. Trace analysis of pesticides in paddy field water by direct injection using liquid chromatography-quadrupole-linear ion trap-mass spectrometry.

    Science.gov (United States)

    Pareja, Lucía; Martínez-Bueno, M J; Cesio, Verónica; Heinzen, Horacio; Fernández-Alba, A R

    2011-07-29

    A multiresidue method was developed for the quantification and confirmation of 70 pesticides in paddy field water. After its filtration, water was injected directly in a liquid chromatograph coupled to a hybrid triple quadrupole-linear ion trap-mass spectrometer (QqLIT). The list of target analytes included organophosphates, phenylureas, sulfonylureas, carbamates, conazoles, imidazolinones and others compounds widely used in different countries where rice is cropped. Detection and quantification limits achieved were in the range from 0.4 to 80 ng L(-1) and from 2 to 150 ng L(-1), respectively. Correlation coefficients for the calibration curves in the range 0.1-50 μg L(-1) were higher than 0.99 except for diazinon (0.1-25 μg L(-1)). Only 9 pesticides presented more than 20% of signal suppression/enhancement, no matrix effect was observed in the studied conditions for the rest of the target pesticides. The method developed was used to investigate the occurrence of pesticides in 59 water samples collected in paddy fields located in Spain and Uruguay. The study shows the presence of bensulfuron methyl, tricyclazole, carbendazim, imidacloprid, tebuconazole and quinclorac in a concentration range from 0.08 to 7.20 μg L(-1). Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Theory of orbital magnetoelectric response

    International Nuclear Information System (INIS)

    Malashevich, Andrei; Souza, Ivo; Coh, Sinisa; Vanderbilt, David

    2010-01-01

    We extend the recently developed theory of bulk orbital magnetization to finite electric fields, and use it to calculate the orbital magnetoelectric (ME) response of periodic insulators. Working in the independent-particle framework, we find that the finite-field orbital magnetization can be written as a sum of three gauge-invariant contributions, one of which has no counterpart at zero field. The extra contribution is collinear with and explicitly dependent on the electric field. The expression for the orbital magnetization is suitable for first-principles implementations, allowing one to calculate the ME response coefficients by numerical differentiation. Alternatively, perturbation-theory techniques may be used, and for that purpose we derive an expression directly for the linear ME tensor by taking the first field-derivative analytically. Two types of terms are obtained. One, the 'Chern-Simons' term, depends only on the unperturbed occupied orbitals and is purely isotropic. The other, 'Kubo' terms, involve the first-order change in the orbitals and give isotropic as well as anisotropic contributions to the response. In ordinary ME insulators all terms are generally present, while in strong Z 2 topological insulators only the Chern-Simons term is allowed, and is quantized. In order to validate the theory, we have calculated under periodic boundary conditions the linear ME susceptibility for a 3D tight-binding model of an ordinary ME insulator, using both the finite-field and perturbation-theory expressions. The results are in excellent agreement with calculations on bounded samples.

  15. Directional effect on coloration in LiF crystal by H{sup +} and H{sub 2}{sup +} ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Gan Mingle; Naramoto, Hiroshi; Aoki, Yasushi; Yamamoto, Shunya; Zeng Jianer; Takeshita, Hidefumi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    In the present paper, the first results are reported about the coloration in LiF crystals induced by bombardments of single hydrogen ions (H{sup +}) and molecular hydrogen ions (H{sub 2}{sup +}) with the same velocity under the <100> aligned and random conditions. For the single hydrogen ion irradiation, the coloration is rather simple. The F-type color center absorption under the <100> aligned condition becomes larger than that under the random condition with the dose increase because of larger fraction of electronic energy loss under channeling condition. On the contrary, the coloration for the molecular ions does not show big channeling effect. In the low dose region some difference can be seen but the difference of coloration is not observed any more with the dose increase. The pronounced coloration for molecular ions under the channeling condition is observed in comparison with that for single ions. (author)

  16. Direct probe of the bent and linear geometries of the core-excited Renner-Teller pair states by means of the triple-ion-coincidence momentum imaging technique

    International Nuclear Information System (INIS)

    Muramatsu, Y.; Ueda, K.; Chiba, H.; Saito, N.; Lavollee, M.; Czasch, A.; Weber, T.; Jagutzki, O.; Schmidt-Boecking, H.; Moshammer, R.; Becker, U.; Kubozuka, K.; Koyano, I.

    2002-01-01

    The doubly degenerate core-excited Π state of CO 2 splits into two due to static Renner-Teller effect. Using the triple-ion-coincidence momentum imaging technique and focusing on the dependence of the measured quantities on the polarization of the incident light, we have probed, directly and separately, the linear and bent geometries for the B 1 and A 1 Renner-Teller pair states, as a direct proof of the static Renner-Teller effect

  17. Negative ion sources for tandem accelerator

    International Nuclear Information System (INIS)

    Minehara, Eisuke

    1980-08-01

    Four kinds of negative ion sources (direct extraction Duoplasmatron ion source, radial extraction Penniing ion source, lithium charge exchange ion source and Middleton-type sputter ion source) have been installed in the JAERI tandem accelerator. The ion sources can generate many negative ions ranging from Hydrogen to Uranium with the exception of Ne, Ar, Kr, Xe and Rn. Discussions presented in this report include mechanisms of negative ion formation, electron affinity and stability of negative ions, performance of the ion sources and materials used for negative ion production. Finally, the author will discuss difficult problems to be overcome in order to get any negative ion sufficiently. (author)

  18. Ion channeling

    International Nuclear Information System (INIS)

    Erramli, H.; Blondiaux, G.

    1994-01-01

    Channeling phenomenon was predicted, many years ago, by stark. The first channeling experiments were performed in 1963 by Davies and his coworkers. Parallely Robinson and Oen have investigated this process by simulating trajectories of ions in monocrystals. This technique has been combined with many methods like Rutherford Backscattering Spectrometry (R.B.S.), Particles Induced X-rays Emission (P.I.X.E) and online Nuclear Reaction (N.R.A.) to localize trace elements in the crystal or to determine crystalline quality. To use channeling for material characterization we need data about the stopping power of the incident particle in the channeled direction. The ratios of channeled to random stopping powers of silicon for irradiation in the direction have been investigated and compared to the available theoretical results. We describe few applications of ion channeling in the field of materials characterization. Special attention is given to ion channeling combined with Charged Particle Activation Analysis (C.P.A.A.) for studying the behaviour of oxygen atoms in Czochralski silicon lattices under the influence of internal gettering and in different gaseous atmospheres. Association between ion channeling and C.P.A.A was also utilised for studying the influence of the growing conditions on concentration and position of carbon atoms at trace levels in the MOVPE Ga sub (1-x) Al sub x lattice. 6 figs., 1 tab., 32 refs. (author)

  19. Vorticity and particle polarization in heavy ion collisions (experimental perspective)

    Science.gov (United States)

    Voloshin, Sergei A.

    2018-02-01

    The recent measurements of the global polarization and vector meson spin alignment along the system orbital momentum in heavy ion collisions are briefly reviewed. A possible connection between the global polarization and the chiral anomalous effects is discussed along with possible experimental checks. Future directions, in particular those aimed on the detailed mapping of the vorticity fields, are outlined. The Blast Wave model is used for an estimate of the anisotropic flow effect on the vorticity component along the beam direction. We also point to a possibility of a circular pattern in the vorticity field in asymmetric, e.g. Cu+Au, central collisions.

  20. Vorticity and particle polarization in heavy ion collisions (experimental perspective

    Directory of Open Access Journals (Sweden)

    Voloshin Sergei A.

    2018-01-01

    Full Text Available The recent measurements of the global polarization and vector meson spin alignment along the system orbital momentum in heavy ion collisions are briefly reviewed. A possible connection between the global polarization and the chiral anomalous effects is discussed along with possible experimental checks. Future directions, in particular those aimed on the detailed mapping of the vorticity fields, are outlined. The Blast Wave model is used for an estimate of the anisotropic flow effect on the vorticity component along the beam direction. We also point to a possibility of a circular pattern in the vorticity field in asymmetric, e.g. Cu+Au, central collisions.

  1. SMART-1 ion engine fired successfully

    Science.gov (United States)

    2003-10-01

    Close-up view of SMART-1's stationary plasma thruster hi-res Size hi-res: 257 kb Credits: ESA 2002. Illustration by Medialab. Close-up view of SMART-1's stationary plasma thruster Electrons attracted into the discharge chamber collide with xenon atoms from the propellant gas supply, making charged atoms (ions). Current-carrying coils, inside and outside the doughnut-shaped discharge chamber, sustain a magnetic field oriented like the spokes of a wheel. By the Hall effect, ions and electrons swerving in opposite directions in the magnetic field create an electric field. This expels the xenon ions in a propulsive jet. Other emitted electrons then neutralize the xenon, producing the blue jet. Engineers at ESOC, the European Space Agency's control centre in Darmstadt, Germany, sent a command to begin the firing test, which lasted for one hour. This was similar to a trial performed on Earth before SMART-1 was launched. Several months ago, the ion engine, or Solar Electric Primary Propulsion (SEPP) system, had been placed in a vacuum chamber on the ground and its functions and operation were measured. Now in space and in a true vacuum, the ion engine actually worked better than in the test on ground and has nudged SMART-1 a little closer to the Moon. This is the first time that Europe flies an electric primary propulsion in space, and also the first European use of this particular type of ion engine, called a 'Hall-effect' thruster. The SEPP consists of a single ion engine fuelled by xenon gas and powered by solar energy. The ion engine will accelerate SMART-1 very gradually to cause the spacecraft to travel in a series of spiralling orbits - each revolution slightly further away from the Earth - towards the Moon. Once captured by the Moon's gravity, SMART-1 will move into ever-closer orbits of the Moon. As part of one of the overall mission objectives to test this new SEPP technology, the data will now be analysed to see how much acceleration was achieved and how

  2. Jupiter Icy Moons Orbiter Mission design overview

    Science.gov (United States)

    Sims, Jon A.

    2006-01-01

    An overview of the design of a possible mission to three large moons of Jupiter (Callisto, Ganymede, and Europa) is presented. The potential Jupiter Icy Moons Orbiter (JIMO) mission uses ion thrusters powered by a nuclear reactor to transfer from Earth to Jupiter and enter a low-altitude science orbit around each of the moons. The combination of very limited control authority and significant multibody dynamics resulted in some aspects of the trajectory design being different than for any previous mission. The results of several key trades, innovative trajectory types and design processes, and remaining issues are presented.

  3. Neonatal orbital abscess

    Directory of Open Access Journals (Sweden)

    Khalil M Al-Salem

    2014-01-01

    Full Text Available Orbital complications due to ethmoiditis are rare in neonates. A case of orbital abscess due to acute ethmoiditis in a 28-day-old girl is presented. A Successful outcome was achieved following antimicrobial therapy alone; spontaneous drainage of the abscess occurred from the lower lid without the need for surgery. From this case report, we intend to emphasize on eyelid retraction as a sign of neonatal orbital abscess, and to review all the available literature of similar cases.

  4. Dual-directional regulation of drug permeating amount by combining the technique of ion-pair complexation with chemical enhancers for the synchronous permeation of indapamide and bisoprolol in their compound patch through rabbit skin.

    Science.gov (United States)

    Song, Wenting; Cun, Dongmei; Quan, Peng; Liu, Nannan; Chen, Yang; Cui, Hongxia; Xiang, Rongwu; Fang, Liang

    2015-04-01

    To achieve the synchronous skin permeation of indapamide (IND) and bisoprolol (BSP) in their compound patch, the techniques of ion-pair complexation and chemical enhancers were combined to dual-directionally regulate drug permeating amounts. Ion-pair complexes of BSP and various organic acids were formed by the technique of ion-pair complexation. Among the complexes formed, bisoprolol tartrate (BSP.T) down-regulated the permeating amount of BSP to the same extent as that of IND. Then, to simultaneously up-regulate the amounts of the two drugs, an enhancer combination of 15.8% Span80 (SP), 6.0% Azone (AZ) and 2.2% N-methyl pyrrolidone (NMP) was obtained by central composite design and exhibited an outstanding and simultaneous enhancement on IND and BSP with enhancing ratio (ER) of 4.52 and 3.49, respectively. The effect of the dual-directional regulation was evaluated by in vitro permeation experiments and in vivo pharmacokinetic studies. For IND and BSP, their observed permeation profiles were comparable and their MAT (mean absorption time) showed no significant difference, which both demonstrated these two drugs achieved the synchronous skin permeation in their compound patch by the dual-directional regulation strategy of combining the technique of ion-pair complexation with chemical enhancers. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Orbital glass in HTSC

    International Nuclear Information System (INIS)

    Kusmartsev, F.V.

    1992-10-01

    The physical reasons why the orbital glass may exist in granular high-temperature superconductors and the existing experimental data appeared recently are discussed. The orbital glass is characterized by the coexistence of the orbital paramagnetic state with the superconducting state and occurs at small magnetic fields H c0 c1 . The transition in orbital glass arises at the critical field H c0 which is inversely proportional to the surface cross-area S of an average grain. In connection with theoretical predictions the possible experiments are proposed. (author). 10 refs

  6. SU-E-T-83: A Study On Evaluating the Directional Dependency of 2D Seven 29 Ion Chamber Array Clinically with Different IMRT Plans

    International Nuclear Information System (INIS)

    Kumar, Syam; Aswathi, C.P.

    2015-01-01

    Purpose: To evaluate the directional dependency of 2D seven 29 ion chamber array clinically with different IMRT plans. Methods: 25 patients already treated with IMRT plans were selected for the study. Verification plans were created for each treatment plan in eclipse 10 treatment planning system using the AAA algorithm with the 2D array and the Octavius CT phantom. Verification plans were done 2 times for a single patient. First plan with real IMRT (plan-related approach) and second plan with zero degree gantry angle (field-related approach). Measurements were performed on a Varian Clinac-iX, linear accelerator equipped with a millennium 120 multileaf collimator. Fluence was measured for all the delivered plans and analyzed using the verisoft software. Comparison was done by selecting the fluence delivered in static gantry (zero degree gantry) versus IMRT with real gantry angles. Results: The gamma pass percentage is greater than 97 % for all IMRT delivered with zero gantry angle and between 95%–98% for real gantry angles. Dose difference between the TPS calculated and measured for IMRT delivered with zero gantry angle was found to be between (0.03 to 0.06Gy) and with real gantry angles between (0.02 to 0.05Gy). There is a significant difference between the gamma analysis between the zero degree and true angle with a significance of 0.002. Standard deviation of gamma pass percentage between the IMRT plans with zero gantry angle was 0.68 and for IMRT with true gantry angle was found to be 0.74. Conclusion: The gamma analysis for IMRT with zero degree gantry angles shows higher pass percentage than IMRT delivered with true gantry angles. Verification plans delivered with true gantry angles lower the verification accuracy when 2D array is used for measurement

  7. The generalized sturmian method for calculating spectra of atoms and ions

    DEFF Research Database (Denmark)

    Avery, James Emil; Avery, John Scales

    2003-01-01

    The properties of generalized Sturmian basis sets are reviewed, and functions of this type are used to perform direct configuration interaction calculations on the spectra of atoms and ions. Singlet excited states calculated in this way show good agreement with experimentally measured spectra. When...... the generalized Sturmian method is applied to atoms, the configurations are constructed from hydrogenlike atomic orbitals with an effective charge which is characteristic of the configuration. Thus, orthonormality between the orbitals of different configurations cannot be assumed, and the generalized Slater...

  8. Collision-Induced Dissociation of Fatty Acid [M - 2H + Na]- Ions: Charge-Directed Fragmentation and Assignment of Double Bond Position

    Science.gov (United States)

    Thomas, Michael C.; Altvater, Jens; Gallagher, Thomas J.; Nette, Geoffrey W.

    2014-08-01

    The collision-induced dissociation (CID) of cationic fatty acid-metal ion complexes has been extensively studied and, in general, provides rich structural information. In particular, charge-remote fragmentation processes are commonly observed allowing the assignment of double bond position. In a previous manuscript, we presented two methods to doubly deprotonate polyunsaturated fatty acids to form anionic fatty acid-sodium ion complexes, referred to as [M - 2H + Na] - ions. In the current manuscript, the CID behavior of these [M - 2H + Na] - ions is investigated for the first time. Significantly, we also present a deuterium-labeling experiment, which excludes the possibility that deprotonation occurs predominately at the α-carbon in the formation of fatty acid [M - H + NaF]- ions. This supports our original proposal where deprotonation occurs at the bis-allylic positions of polyunsaturated fatty acids. CID spectra of polyunsaturated fatty acid [M - 2H + Na]- ions display abundant product ions arising from acyl chain cleavages. Through the examination of fatty acid isomers, it is demonstrated that double bond position may be unequivocally determined for methylene-interrupted polyunsaturated fatty acids with three or more carbon-carbon double bonds. In addition, CID of [M - 2H + Na]- ions was applied to 18:3 isomers of Nannochloropsis oculata and three isomers were tentatively identified: Δ9,12,1518:3, Δ6,9,1218:3, and Δ5,8,1118:3. We propose that structurally-informative product ions are formed via charge-driven fragmentation processes at the site of the resonance-stabilized carbanion as opposed to charge-remote fragmentation processes, which could be inferred if deprotonation occurred predominately at the α-carbon.

  9. Spin-orbit transitions in α - and γ -CoV2O6

    Science.gov (United States)

    Wallington, F.; Arevalo-Lopez, A. M.; Taylor, J. W.; Stewart, J. R.; Garcia-Sakai, V.; Attfield, J. P.; Stock, C.

    2015-09-01

    γ -triclinic and α -monoclinic polymorphs of CoV2O6 are two of the few known transition-metal ion-based materials that display stepped 1/3 magnetization plateaus at low temperatures. Neutron diffraction [M. Markkula et al., Phys. Rev. B 86, 134401 (2012)], 10.1103/PhysRevB.86.134401, x-ray dichroism [N. Hollmann et al., Phys. Rev. B 89, 201101(R) (2014)], 10.1103/PhysRevB.89.201101, and dielectric measurements [J. Singh et al., J. Mater. Chem. 22, 6436 (2012)], 10.1039/c2jm16290c have shown a coupling between orbital, magnetic, and structural orders in CoV2O6 . We apply neutron inelastic scattering to investigate this coupling by measuring the spin-orbit transitions in both α and γ polymorphs. We find the spin exchange and anisotropy in monoclinic α -CoV2O6 to be weak in comparison with the spin-orbit coupling λ and estimate an upper limit of |J /λ |˜ 0.05 . However, the spin exchange is larger in the triclinic polymorph and we suggest the excitations are predominately two dimensional. The local compression of the octahedra surrounding the Co2 + ion results in a direct coupling between higher-energy orbital levels, the magnetic ground state, and elastic strain. CoV2O6 is therefore an example where the local distortion along with the spin-orbit coupling provides a means of intertwining structural and magnetic properties. We finish the paper by investigating the low-energy magnetic fluctuations within the ground-state doublet and report a magnetic excitation that is independent of the local crystalline electric field. We characterize the temperature and momentum dependence of these excitations and discuss possible connections to the magnetization plateaus.

  10. Titan Orbiter Aerorover Mission

    Science.gov (United States)

    Sittler Jr., E. C.; Acuna, M.; Burchell, M. J.; Coates, A.; Farrell, W.; Flasar, M.; Goldstein, B. E.; Gorevan, S.; Hartle, R. E.; Johnson, W. T. K.

    2001-01-01

    We propose a combined Titan orbiter and Titan Aerorover mission with an emphasis on both in situ and remote sensing measurements of Titan's surface, atmosphere, ionosphere, and magnetospheric interaction. The biological aspect of the Titan environment will be emphasized by the mission (i.e., search for organic materials which may include simple organics to 'amono' analogues of amino acids and possibly more complex, lightening detection and infrared, ultraviolet, and charged particle interactions with Titan's surface and atmosphere). An international mission is assumed to control costs. NASA will provide the orbiter, launch vehicle, DSN coverage and operations, while international partners will provide the Aerorover and up to 30% of the cost for the scientific instruments through collaborative efforts. To further reduce costs we propose a single PI for orbiter science instruments and a single PI for Aerorover science instruments. This approach will provide single command/data and power interface between spacecraft and orbiter instruments that will have redundant central DPU and power converter for their instruments. A similar approach could be used for the Aerorover. The mission profile will be constructed to minimize conflicts between Aerorover science, orbiter radar science, orbiter radio science, orbiter imaging science, and orbiter fields and particles (FP) science. Additional information is contained in the original extended abstract.

  11. MRI of orbital schwannomas

    Energy Technology Data Exchange (ETDEWEB)

    Abe, T.; Kawamura, N.; Homma, H.; Sasaki, K.; Izumimaya, H.; Matsumoto, K. [Department of Neurosurgery, Showa University School of Medicine, 5-8 Hatanodai 1, Shinagawa-ku, Tokyo 142-8666 (Japan)

    2000-06-01

    The literature on MRI of orbital schwannomas is limited. The appearances in three patients with an orbital schwannoma were reviewed. A superior orbitotomy through a subfrontal craniotomy revealed a schwannoma in all cases. MRI characteristics of very low signal on T 1-weighted images and homogeneous postcontrast enhancement may be helpful for differentiating schwannomas from other intraconal masses. (orig.)

  12. Multicharged ion sources

    International Nuclear Information System (INIS)

    Venikov, N.I.

    1979-01-01

    The main principles of action, beam parameters, basic problems and prospects for development of the available multicharged ion sources for various types of accelerators are considered. Descriptions of three types of Penneng sources (a source with coid cathodes, direct-heated source, and a source with a heated cathode), duoplasmatron, SHP source using electron-cyclotron resonance, electron-ray and laser sources are given. The problems productions for solid substance ions, lithium and beryllium ions in Penning sources, are considered as well as the problem of ion charge growth on passage of accelerated ion/or atom beam through a stripping target [ru

  13. Peripheral orbit model

    CERN Document Server

    Hara, Yasuo

    1975-01-01

    Peripheral orbit model, in which an incoming hadron is assumed to revolve in a peripheral orbit around a target hadron, is discussed. The non-diffractive parts of two-body reaction amplitudes of hadrons are expressed in terms of the radius, width an absorptivity of the orbit. The radius of the orbit is about 1 fm and the width of the orbit is determined by the range of the interaction between the hadrons. The model reproduces all available experimental data on differential cross-sections and polarizations of $K^{-}p\\to K^{-}p$ and $\\bar K^{\\circ}n$ reactions for all angles successfully. This contribution is not included in the proceedings since it will appear in Progress of Theoretical Physics Vol. 51 (1974) No 2. Any person interested in the subject may apply for reprints to the author.

  14. Ion mobility sensor system

    Science.gov (United States)

    Xu, Jun; Watson, David B.; Whitten, William B.

    2013-01-22

    An ion mobility sensor system including an ion mobility spectrometer and a differential mobility spectrometer coupled to the ion mobility spectrometer. The ion mobility spectrometer has a first chamber having first end and a second end extending along a first direction, and a first electrode system that generates a constant electric field parallel to the first direction. The differential mobility spectrometer includes a second chamber having a third end and a fourth end configured such that a fluid may flow in a second direction from the third end to the fourth end, and a second electrode system that generates an asymmetric electric field within an interior of the second chamber. Additionally, the ion mobility spectrometer and the differential mobility spectrometer form an interface region. Also, the first end and the third end are positioned facing one another so that the constant electric field enters the third end and overlaps the fluid flowing in the second direction.

  15. Wind and Temperature Spectrometry of the Upper Atmosphere in Low-Earth Orbit

    Science.gov (United States)

    Herrero, Federico

    2011-01-01

    Wind and Temperature Spectrometry (WATS) is a new approach to measure the full wind vector, temperature, and relative densities of major neutral species in the Earth's thermosphere. The method uses an energy-angle spectrometer moving through the tenuous upper atmosphere to measure directly the angular and energy distributions of the air stream that enters the spectrometer. The angular distribution gives the direction of the total velocity of the air entering the spectrometer, and the energy distribution gives the magnitude of the total velocity. The wind velocity vector is uniquely determined since the measured total velocity depends on the wind vector and the orbiting velocity vector. The orbiting spectrometer moves supersonically, Mach 8 or greater, through the air and must point within a few degrees of its orbital velocity vector (the ram direction). Pointing knowledge is critical; for example, pointing errors 0.1 lead to errors of about 10 m/s in the wind. The WATS method may also be applied without modification to measure the ion-drift vector, ion temperature, and relative ion densities of major ionic species in the ionosphere. In such an application it may be called IDTS: Ion-Drift Temperature Spectrometry. A spectrometer-based coordinate system with one axis instantaneously pointing along the ram direction makes it possible to transform the Maxwellian velocity distribution of the air molecules to a Maxwellian energy-angle distribution for the molecular flux entering the spectrometer. This implementation of WATS is called the gas kinetic method (GKM) because it is applied to the case of the Maxwellian distribution. The WATS method follows from the recognition that in a supersonic platform moving at 8,000 m/s, the measurement of small wind velocities in the air on the order of a few 100 m/s and less requires precise knowledge of the angle of incidence of the neutral atoms and molecules. The same is true for the case of ion-drift measurements. WATS also

  16. Small Orbital Stereo Tracking Camera Technology Development

    Science.gov (United States)

    Bryan, Tom; MacLeod, Todd; Gagliano, Larry

    2017-01-01

    Any exploration vehicle assembled or Spacecraft placed in LEO or GTO must pass through this debris cloud and survive. Large cross section, low thrust vehicles will spend more time spiraling out through the cloud and will suffer more impacts.Better knowledge of small debris will improve survival odds. Current estimated Density of debris at various orbital attitudes with notation of recent collisions and resulting spikes. Orbital Debris Tracking and Characterization has now been added to NASA Office of Chief Technologists Technology Development Roadmap in Technology Area 5 (TA5.7)[Orbital Debris Tracking and Characterization] and is a technical gap in the current National Space Situational Awareness necessary to safeguard orbital assets and crews due to the risk of Orbital Debris damage to ISS Exploration vehicles. The Problem: Traditional orbital trackers looking for small, dim orbital derelicts and debris typically will stare at the stars and let any reflected light off the debris integrate in the imager for seconds, thus creating a streak across the image. The Solution: The Small Tracker will see Stars and other celestial objects rise through its Field of View (FOV) at the rotational rate of its orbit, but the glint off of orbital objects will move through the FOV at different rates and directions. Debris on a head-on collision course (or close) will stay in the FOV at 14 Km per sec. The Small Tracker can track at 60 frames per sec allowing up to 30 fixes before a near-miss pass. A Stereo pair of Small Trackers can provide range data within 5-7 Km for better orbit measurements.

  17. Ion source

    International Nuclear Information System (INIS)

    Saito, Fusao; Okuyama, Toshihisa; Suzuki, Yasuo.

    1996-01-01

    In a negative ion source having magnetic filters, bisecting magnetic fields are formed using electromagnets disposed at the outside of a plasma source. The position of the electromagnets is made adjustable and removable to optimize a negative ion generation efficiency. Further, a plurality of electromagnets are disposed in longitudinal direction of the plasma source, and the intensity of the magnetic fields of the filters in the longitudinal direction is made adjustable to control a beam distribution. Since uniform magnetic fields which bisect the plasma source can be formed by the electromagnets, and magnetomotive force of the electromagnets can be increased easily compared with that of permanent magnets, the magnetomotive force is changed to obtain appropriate filter magnetic fields easily. Then, optimum magnetic fields corresponding to the state of source plasmas can be generated by the control of the power source of the electromagnets, which also increases the negative ion drawing current density, thereby enabling to reduce the drawing area and size of the plasma source. (N.H.)

  18. Behaviour of direct and delayed fast ion losses during NBI on TJ-II; Comportamiento de las perdidas instantaneas y retardadas en la inyeccion de neutros del TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Guasp, J.; Liniers, M.

    1995-07-01

    The dependence with density and beam energy of the different kind of fast ion losses, direct and delayed, during tangential balanced NBI injection in TJ-II helical axis stellarator has been analysed. Direct losses increase with energy and a strong difference between the two injection directions appears, are produced by passing particles that loss confinement in a few {mu}sec and the influence of birth profiles produces an increase with density. Delayed losses are very well separated in time from direct ones, are produced by particles experimenting pitch angle scattering and, most o them, correspond to trapped particles. Are much less important than the direct ones (about 1/3), decrease slowly with energy and, with C X, increase with density (an effect of initial profile). The absorption is rather independent of energy with low values at low density in reason of high shine through and C X losses, but recovers quickly with the density increase. (Author) 4 refs.

  19. Study of the Kramers rare earth ions ground multiplet with a large orbital contribution by multifrequency EPR spectroscopy: Ce.sup.3+./sup. in PbWO.sub.4./sub. scintillator

    Czech Academy of Sciences Publication Activity Database

    Popescu, F.F.; Bercu, V.; Barascu, J.N.; Martinelli, M.; Massa, C.A.; Pardi, L.A.; Stefan, M.; Nistor, S.V.; Nikl, Martin

    2010-01-01

    Roč. 32, č. 5 (2010), s. 570-575 ISSN 0925- 3467 Institutional research plan: CEZ:AV0Z10100521 Keywords : rare earth ions * crystal field splitting * electron paramagnetic resonance (EPR) Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.679, year: 2010

  20. Plasmons with orbital angular momentum

    International Nuclear Information System (INIS)

    Mendonca, J. T.; Ali, S.; Thide, B.

    2009-01-01

    Electron plasma waves carrying orbital angular momentum are investigated in an unmagnetized collisionless plasma composed of inertial electrons and static ions. For this purpose, the usual plasmon dispersion relation is employed to derive an approximate paraxial equation. The latter is analyzed with a Gaussian beam solution. For a finite angular momentum associated with the plasmon, Laguerre-Gaussian (LG) solutions are employed for solving the electrostatic potential problem which gives approximate solution and is valid for plasmon beams in the paraxial approximation. The LG potential determines the electric field components and energy flux of plasmons with finite angular momentum. Numerical illustrations show that the radial and angular mode numbers strongly modify the profiles of the LG potential.

  1. Energy Flow in Saturn's Ion Cyclotron Wave Belt

    Science.gov (United States)

    Leisner, J. S.; Russell, C. T.; Dougherty, M. K.; Persoon, A. M.; Blanco-Cano, X.; McAndrews, H. J.; Thomsen, M. F.; Strangeway, R. J.

    2007-12-01

    When molecules in Saturn's water-group neutral cloud are ionized, they are accelerated by the electric field associated with the motion of the magnetospheric plasma. This acceleration brings the pick-up ions to the bulk plasma speed and gives them free energy that leads to the growth of ion cyclotron waves. Ion cyclotron waves propagating along the magnetic field have been observed near the equatorial plane on almost all of Cassini's orbits through the inner magnetosphere. On near-equatorial orbits, these waves are observed to peak below the gyrofrequencies of water-group (O, OH, H2O) and molecular oxygen (O2) ions. On inclined orbits, the velocity of the spacecraft along the waves' direction of propagation produced Doppler shifts in the wave frequency. Using this shift, we calculate the phase velocity of the waves through the wave belt. We find that near the magnetic equator, the waves are propagating both parallel and anti-parallel to the magnetic field and have phase velocities of 40-50 km/s, one-half to one-third of the local Alfven speed. Beyond +/- 0.04 Rs of the magnetic equator, the water-group waves are propagating away from that plane and increasing in power until about +/- 0.25 Rs. Then they quickly damp. The wave power profile is similar for molecular oxygen waves, except these waves are about one-tenth as strong. Beyond +/- 0.3 Rs of the magnetic equator the water-group waves are absent, but the molecular oxygen waves persist until higher latitudes, although with low power. We discuss the energy carried by these waves, considering both ion species and where the background plasma gains energy from their absorption.

  2. Topology of tokamak orbits

    International Nuclear Information System (INIS)

    Rome, J.A.; Peng, Y.K.M.

    1978-09-01

    Guiding center orbits in noncircular axisymmetric tokamak plasmas are studied in the constants of motion (COM) space of (v, zeta, psi/sub m/). Here, v is the particle speed, zeta is the pitch angle with respect to the parallel equilibrium current, J/sub parallels/, and psi/sub m/ is the maximum value of the poloidal flux function (increasing from the magnetic axis) along the guiding center orbit. Two D-shaped equilibria in a flux-conserving tokamak having β's of 1.3% and 7.7% are used as examples. In this space, each confined orbit corresponds to one and only one point and different types of orbits (e.g., circulating, trapped, stagnation and pinch orbits) are represented by separate regions or surfaces in the space. It is also shown that the existence of an absolute minimum B in the higher β (7.7%) equilibrium results in a dramatically different orbit topology from that of the lower β case. The differences indicate the confinement of additional high energy (v → c, within the guiding center approximation) trapped, co- and countercirculating particles whose orbit psi/sub m/ falls within the absolute B well

  3. Backtrack Orbit Search Algorithm

    Science.gov (United States)

    Knowles, K.; Swick, R.

    2002-12-01

    A Mathematical Solution to a Mathematical Problem. With the dramatic increase in satellite-born sensor resolution traditional methods of spatially searching for orbital data have become inadequate. As data volumes increase end-users of the data have become increasingly intolerant of false positives. And, as computing power rapidly increases end-users have come to expect equally rapid search speeds. Meanwhile data archives have an interest in delivering the minimum amount of data that meets users' needs. This keeps their costs down and allows them to serve more users in a more timely manner. Many methods of spatial search for orbital data have been tried in the past and found wanting. The ever popular lat/lon bounding box on a flat Earth is highly inaccurate. Spatial search based on nominal "orbits" is somewhat more accurate at much higher implementation cost and slower performance. Spatial search of orbital data based on predict orbit models are very accurate at a much higher maintenance cost and slower performance. This poster describes the Backtrack Orbit Search Algorithm--an alternative spatial search method for orbital data. Backtrack has a degree of accuracy that rivals predict methods while being faster, less costly to implement, and less costly to maintain than other methods.

  4. Orbital cellulitis in children.

    Science.gov (United States)

    Nageswaran, Savithri; Woods, Charles R; Benjamin, Daniel K; Givner, Laurence B; Shetty, Avinash K

    2006-08-01

    To review the epidemiology and management of orbital cellulitis in children. The medical records of children orbital cellulitis and confirmed by computed tomography scan were reviewed. A literature search for additional studies for systematic review was also conducted. Forty-one children with orbital cellulitis were identified. The mean age was 7.5 years (range, 10 months to 16 years), and 30 (73%) were male (male:female ratio = 2.7). All cases of orbital cellulitis were associated with sinusitis; ethmoid sinusitis was present in 40 (98%) patients. Proptosis and/or ophthalmoplegia was documented in 30 (73%), and 34 (83%) had subperiosteal and/or orbital abscesses. Twenty-nine (71%) had surgical drainage and 12 (29%) received antibiotic therapy only. The mean duration of hospitalization was 5.8 days. The mean duration of antibiotic therapy was 21 days. Orbital cellulitis occurs throughout childhood and in similar frequency among younger and older children. It is twice as common among males as females. Selected cases of orbital cellulitis, including many with subperiosteal abscess, can be treated successfully without surgical drainage.

  5. Harmonically excited orbital variations

    International Nuclear Information System (INIS)

    Morgan, T.

    1985-01-01

    Rephrasing the equations of motion for orbital maneuvers in terms of Lagrangian generalized coordinates instead of Newtonian rectangular cartesian coordinates can make certain harmonic terms in the orbital angular momentum vector more readily apparent. In this formulation the equations of motion adopt the form of a damped harmonic oscillator when torques are applied to the orbit in a variationally prescribed manner. The frequencies of the oscillator equation are in some ways unexpected but can nonetheless be exploited through resonant forcing functions to achieve large secular variations in the orbital elements. Two cases are discussed using a circular orbit as the control case: (1) large changes in orbital inclination achieved by harmonic excitation rather than one impulsive velocity change, and (2) periodic and secular changes to the longitude of the ascending node using both stable and unstable excitation strategies. The implications of these equations are also discussed for both artificial satellites and natural satellites. For the former, two utilitarian orbits are suggested, each exploiting a form of harmonic excitation. 5 refs

  6. Double perovskites with strong spin-orbit coupling

    Science.gov (United States)

    Cook, Ashley M.

    account for the neutron data as well as the measured frustration parameters of these materials, while the uniaxial Ising anisotropy does not. Our findings highlight how even seemingly conventional magnetic orders in oxide materials containing heavy transition metal ions may be driven by highly-directional exchange interactions rooted in strong spin-orbit coupling. Motivated by experiments on the double perovskites La2ZnIrO 6 and La2MgIrO6, we lastly study the magnetism of spin-orbit coupled jeff =1/2 iridium moments on the three-dimensional, geometrically frustrated, facecentered cubic lattice. The symmetry-allowed nearest-neighbor interaction includes Heisenberg, Kitaev, and symmetric off-diagonal exchange. A Luttinger-Tisza analysis shows a rich variety of orders, including collinear AII type antiferromagnetism, stripe order with moments along the {111}-direction, and incommensurate non-coplanar spirals, and we use Monte Carlo simulations to determine their magnetic ordering temperatures.

  7. The Global Precipitation Measurement (GPM) Spacecraft Power System Design and Orbital Performance

    Science.gov (United States)

    Dakermanji, George; Burns, Michael; Lee, Leonine; Lyons, John; Kim, David; Spitzer, Thomas; Kercheval, Bradford

    2016-01-01

    The Global Precipitation Measurement (GPM) spacecraft was jointly developed by National Aeronautics and Space Administration (NASA) and Japan Aerospace Exploration Agency (JAXA). It is a Low Earth Orbit (LEO) spacecraft launched on February 27, 2014. The spacecraft is in a circular 400 Km altitude, 65 degrees inclination nadir pointing orbit with a three year basic mission life. The solar array consists of two sun tracking wings with cable wraps. The panels are populated with triple junction cells of nominal 29.5% efficiency. One axis is canted by 52 degrees to provide power to the spacecraft at high beta angles. The power system is a Direct Energy Transfer (DET) system designed to support 1950 Watts orbit average power. The batteries use SONY 18650HC cells and consist of three 8s x 84p batteries operated in parallel as a single battery. The paper describes the power system design details, its performance to date and the lithium ion battery model that was developed for use in the energy balance analysis and is being used to predict the on-orbit health of the battery.

  8. Antenatal sonographic appearance of a large orbital encephalocele: a case report and differential diagnosis of orbital cystic mass.

    Science.gov (United States)

    Ahmed, Ahmed; Noureldin, Rehab; Gendy, Mohamed; Sakr, Sharif; Abdel Naby, Mahmoud

    2013-06-01

    Orbital meningoceles and encephaloceles are rare extracranial extensions of the brain and meninges with or without direct communication between the central nervous system and the abnormal mass. We reported a rare case of large fetal orbital encephalocele; the diagnosis was suspected initially by prenatal ultrasound and confirmed by postnatal MRI and CT scans. The differential diagnosis of an intrauterine fetal cystic orbital mass includes orbital teratoma, epidermoid inclusion cysts, hemangioma or lymphangioma, congenital cystic eye, dacryocystocele, and orbital cephalocele. Copyright © 2012 Wiley Periodicals, Inc.

  9. Characterization and application of automated in-vacuum PIXE/EBS system for direct analysis of chloride and sulfate ions attack in cementitious materials

    Science.gov (United States)

    Rihawy, M. S.; Alwazzeh, M.; Abbas, K.

    2018-01-01

    Ion beam analysis (IBA) techniques (Particle Induced X-ray Emission, PIXE and Elastic Backscattering Spectrometry, EBS), were applied to investigate chloride and sulfate ions diffusion into laboratory prepared mortar samples. Development and characterization of an automated in-vacuum macro PIXE/EBS system is thoroughly discussed. Depth profile information of both chloride and sulfate ions in laboratory prepared mortar samples, after immersion in sea water for nine months, was rapidly and easily obtained at fairly low cost and with standardless analysis, demonstrating the value of the application of IBA to elemental depth profiling in cementitious materials. Chloride and sulfate depth profiles were obtained for two sets of mortar samples, one prepared with different water/cement (W/C) ratios and the other with different sand/cement (S/C) ratios. Results showed higher diffusion rates of both chloride and sulfate ions when both ratios are increased. Additionally, the W/C ratio has a stronger influence in both sulfate and chloride penetration than the S/C ratio, and chloride ions penetrate faster than sulfates. Advantages and limitations of applying IBA techniques in this investigation are discussed. The comparison between PIXE and other X-ray based analytical techniques, namely X-ray fluorescence (XRF) and energy and wavelength dispersive X-rays (EDX/WDX), as well as other traditional wet chemical methods is reviewed, and industrial applications are discussed.

  10. Quark Orbital Angular Momentum

    Directory of Open Access Journals (Sweden)

    Burkardt Matthias

    2015-01-01

    Full Text Available Definitions of orbital angular momentum based on Wigner distributions are used as a framework to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. We find that the difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asymmetries in semi-inclusive deep-inelastic scattering.

  11. Determination of Trace Anions in Concentrated Hydrogen Peroxide by Direct Injection Ion Chromatography with Conductivity Detection after Pt-Catalyzed On-Line Decomposition

    International Nuclear Information System (INIS)

    Kim, Do Hee; Lee, Bo Kyung; Lee, Dong Soo

    1999-01-01

    A method has been developed for the determination of trace anion impurities in concentrated hydrogen peroxide. The method involves on-line decomposition of hydrogen peroxide, ion chromatographic separation and subsequent suppressed-type conductivity detection. H 2 O 2 is decomposed in Pt-catalyst filled Gore-Tex membrane tubing and the resulting aqueous solution containing analytes is introduced to the injection valve of an ion chromatograph for periodic determinations. The oxygen gas evolving within the membrane tubing escapes freely through the membrane wall causing no problem in ion chromatographic analysis. Decomposition efficiency is above 99.99% at a flow rate of 0.4mL/min for a 30% hydrogen peroxide concentration. Analytes are quantitatively retained. The analysis results for several brands of commercial hydrogen peroxides are reported

  12. The electric wind of Venus: A global and persistent "polar wind"-like ambipolar electric field sufficient for the direct escape of heavy ionospheric ions

    Science.gov (United States)

    Collinson, Glyn A.; Frahm, Rudy A.; Glocer, Alex; Coates, Andrew J.; Grebowsky, Joseph M.; Barabash, Stas; Domagal-Goldman, Shawn D.; Fedorov, Andrei; Futaana, Yoshifumi; Gilbert, Lin K.; Khazanov, George; Nordheim, Tom A.; Mitchell, David; Moore, Thomas E.; Peterson, William K.; Winningham, John D.; Zhang, Tielong L.

    2016-06-01

    Understanding what processes govern atmospheric escape and the loss of planetary water is of paramount importance for understanding how life in the universe can exist. One mechanism thought to be important at all planets is an "ambipolar" electric field that helps ions overcome gravity. We report the discovery and first quantitative extraterrestrial measurements of such a field at the planet Venus. Unexpectedly, despite comparable gravity, we show the field to be five times stronger than in Earth's similar ionosphere. Contrary to our understanding, Venus would still lose heavy ions (including oxygen and all water-group species) to space, even if there were no stripping by the solar wind. We therefore find that it is possible for planets to lose heavy ions to space entirely through electric forces in their ionospheres and such an "electric wind" must be considered when studying the evolution and potential habitability of any planet in any star system.

  13. The Electric Wind of Venus: A global and persistent "polar wind" like ambipolar electric field sufficient for the direct escape of heavy ionospheric ions

    Science.gov (United States)

    Collinson, G.; Frahm, R.; Glocer, A.; Coates, A. J.; Grebowsky, J. M.; Barbash, S.; Fedorov, A.; Futaana, Y.; Gilbert, L.; Khazanov, G. V.; Domagal-Goldman, S. D.; Nordheim, T.; Mitchell, D. L.; Moore, T. E.; Peterson, W.; Winningham, D.; Zhang, T.

    2016-12-01

    Understanding what processes govern atmospheric escape and the loss of planetary water is of paramount importance for understanding how life in the universe can exist. One mechanism thought to be important at all planets is an "ambipolar" electric field that helps ions overcome gravity. We report the discovery and first quantitative extraterrestrial measurements of such a field at the planet Venus. Unexpectedly, despite comparable gravity, we show the field to be five times stronger than in Earth's similar ionosphere. Contrary to our understanding, Venus would still lose heavy ions (including oxygen and all water-group species) to space, even if there were no stripping by the solar wind. We therefore find it is possible for planets to lose heavy ions to space entirely through electric forces in their ionospheres, and such an "electric wind" must be considered when studying the evolution and potential habitability of any planet in any star system

  14. The Electric Wind of Venus: A Global and Persistent Polar Wind -Like Ambipolar Electric Field Sufficient for the Direct Escape of Heavy Ionospheric Ions

    Science.gov (United States)

    Collinson, Glyn A.; Frahm, Rudy A.; Glocer, Alex; Coates, Andrew J.; Grebowsky, Joseph M.; Barabash, Stas; Domagal-Goldman, Shawn D.; Federov, Andrei; Futaana, Yoshifumi; Gilbert, Lin K.; hide

    2016-01-01

    Understanding what processes govern atmospheric escape and the loss of planetary water is of paramount importance for understanding how life in the universe can exist. One mechanism thought to be important at all planets is an ambipolar electric field that helps ions overcome gravity. We report the discovery and first quantitative extraterrestrial measurements of such a field at the planet Venus. Unexpectedly, despite comparable gravity, we show the field to be five times stronger than in Earths similar ionosphere. Contrary to our understanding, Venus would still lose heavy ions (including oxygen and all water-group species) to space, even if there were no stripping by the solar wind. We therefore find that it is possible for planets to lose heavy ions to space entirely through electric forces in their ionospheres and such an electric wind must be considered when studying the evolution and potential habitability of any planet in any star system.

  15. Exit points, on plasma, of lost fast ions during NBI in TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.

    1995-01-01

    The distribution of the exit points, on plasma border, for the lost fast ions during tangential balanced NBI in TJ-II helical axis Stellarator is theoretically analysed, as well for direct as for delayed losses. The link between, the position of those exit points and the corresponding at birth, orbits and drifts is analysed also. It is shown that such relation is rather independent of beam energy and plasma density and is mainly related to the magnetic configuration characteristics. This study is a needed intermediate step to the analysis of impacts of those ions on the vacuum vessel of TJ-II. (Author) 2 refs

  16. Exit points, on plasma, of lost fast ions during NBI in TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.

    1995-09-01

    The distribution of the exit points, on plasma border, for the lost fast ions during tangential balanced NBI in TJ-II helical axis Stellarator is theoretically analysed, as well for direct as for delayed losses. The link between the position of those exit points and the corresponding at birth, orbits and drifts is analysed also, it is shown that such relation is rather independent of beam energy and plasma density and is mainly related to the magnetic configuration characteristics. This study is a needed intermediate step to the analysis of impacts of those ions on the vacuum vessel of TJ-II

  17. Optical lattices: Orbital dance

    Science.gov (United States)

    Lewenstein, Maciej; Liu, W. Vincent

    2011-02-01

    Emulating condensed-matter physics with ground-state atoms trapped in optical lattices has come a long way. But excite the atoms into higher orbital states, and a whole new world of exotic states appears.

  18. Neonatal orbital abscess

    Directory of Open Access Journals (Sweden)

    Pratik Y Gogri

    2015-01-01

    Full Text Available Orbital abscess generally occurs in older children but it can rarely affect infants and neonates too. We report a case of community acquired methicillin resistant staphylococcus aureus (CA-MRSA neonatal orbital abscess in a 12-day-old term female neonate with no significant past medical history or risk factor for developing the infection. The case highlights the importance of consideration of CA-MRSA as a causative agent of neonatal orbital cellulitis even in a neonate without any obvious predisposing condition. Prompt initiation of appropriate medical therapy against MRSA and surgical drainage of the abscess prevents life threatening complications of orbital cellulitis which more often tend to be fatal in neonates.

  19. Congenital orbital teratoma

    Directory of Open Access Journals (Sweden)

    Shereen Aiyub

    2013-01-01

    Full Text Available We present a case of mature congenital orbital teratoma managed with lid-sparing exenteration and dermis fat graft. This is a case report on the management of congenital orbital teratoma. A full-term baby was born in Fiji with prolapsed right globe which was surrounded by a nonpulsatile, cystic mass. Clinical and imaging features were consistent with congenital orbital teratoma. Due to limited surgical expertise, the patient was transferred to Adelaide, Australia for further management. The patient underwent a lid-sparing exenteration with frozen section control of the apical margin. A dermis fat graft from the groin was placed beneath the lid skin to provide volume. Histopathology revealed mature tissues from each of the three germ cell layers which confirmed the diagnosis of mature teratoma. We describe the successful use of demis fat graft in socket reconstruction following lid-sparing exenteration for congenital orbital teratoma.

  20. Envelopes of Cometary Orbits

    Directory of Open Access Journals (Sweden)

    Mijajlović, Ž.

    2008-12-01

    Full Text Available We discuss cometary orbits from the standpoint of Nonstandard (Leibnitz analysis, a relatively new branch of mathematics. In particular, we consider parabolic cometary paths. It appears that, in a sense, every parabola is an ellipse.

  1. Eye and orbit ultrasound

    Science.gov (United States)

    ... the retina, or in other parts of the eye (such as melanoma ) Damaged tissue or injuries in the bony socket (orbit) that surrounds and protects the eye Foreign bodies Pulling away of the retina from ...

  2. Periodic orbits near the particle resonance in galaxies

    CERN Document Server

    Contopoulos, George

    1978-01-01

    Near the particle resonance of a spiral galaxy the almost circular periodic orbits that exist inside the resonance (direct) or outside it (retrograde) are replaced by elongated trapped orbits around the maxima of the potential L/sub 4/ and L/sub 5/. These are the long- period trapped periodic orbits. The long-period orbits shrink to the points L/sub 4/, L/sub 5/ for a critical value of the Hamiltonian h. For still larger h, a family of short-period trapped orbits appears, with continuously growing size. The evolution of the periodic orbits with h is followed, theoretically and numerically, from the untrapped orbits to the long-periodic orbits and then to the short-periodic orbits, mainly in the case of a bar. In a tight spiral case an explanation of the asymmetric periodic and banana orbits is given, and an example of short-period orbits not surrounding L/sub 4/ or L/sub 5/ is provided. Another family of periodic orbits reaching corotation is trapped at the inner Lindblad resonance. (5 refs).

  3. Orbital retinoblastoma: An update

    Science.gov (United States)

    Honavar, Santosh G; Manjandavida, Fairooz P; Reddy, Vijay Anand P

    2017-01-01

    Orbital extension is a major cause of death in children with retinoblastoma in the developing countries. Delayed detection and inappropriate management contribute to poor outcome. Conventional treatment including primary orbital exenteration or chemotherapy or radiotherapy alone result in mortality as high as 70%. The recent understanding on the role of sequential multimodal therapy with a combination of high-dose chemotherapy, followed by appropriate surgery, radiotherapy, and additional adjuvant chemotherapy has helped dramatically improve life salvage. PMID:28643706

  4. Orbital interactions in chemistry

    CERN Document Server

    Albright, Thomas A; Whangbo, Myung-Hwan

    2013-01-01

    Explains the underlying structure that unites all disciplines in chemistry Now in its second edition, this book explores organic, organometallic, inorganic, solid state, and materials chemistry, demonstrating how common molecular orbital situations arise throughout the whole chemical spectrum. The authors explore the relationships that enable readers to grasp the theory that underlies and connects traditional fields of study within chemistry, thereby providing a conceptual framework with which to think about chemical structure and reactivity problems. Orbital Interactions

  5. Self-consistent analysis of radial electric field and fast ion losses in CHS Torsatron/Heliotron

    International Nuclear Information System (INIS)

    Sanuki, H.; Itoh, K.; Itoh, S.

    1992-09-01

    A self-consistent analysis is developed to determine the radial electric field and loss cone boundary in Torsatron/Heliotron plasmas under the influence of non-classical ion losses such as the loss cone loss ans charge exchange loss of fast ions with neutrals. Analysis is applied to the NBI heated plasmas in the Compact Helical System (CHS) device. Comparison is made between theoretical results and experimental observations. The increased ion particle losses caused by the orbit loss and charge exchange loss with neutrals make the radial electric field more negative than the value of purely neoclassical calculation. The partition of the injection energy among the shine through, direct orbit loss, change exchange loss and bulk heating is evaluated by using the self-consistent electric field profile. On-going experiments in the CHS device are briefly introduced. (author)

  6. Meteoric Impact and Ion Density Calculation in the Nighttime ...

    Indian Academy of Sciences (India)

    Bhavin

    2013-11-08

    Nov 8, 2013 ... Future Missions to Mars: MAVEN-Orbiter (NASA). Determine Current State of the Atmosphere/Ionosphere/Solar Wind. Interaction, Escape of Neutrals & Ions from Mars. Indian Mars Mission-Mangalyaan. Atmosphere/Ionosphere, Escape of Neutrals & Ions from Mars. MELOS-Orbiter & Lander (Japan).

  7. Juno/JEDI observations of energetic particles near closest approach to Jupiter - Evidence for heavy ion precipitation in the Jovian auroral region

    Science.gov (United States)

    Haggerty, Dennis; Mauk, Barry; Paranicas, Chris; Clark, George; Kollmann, Peter; Rymer, Abigail; Bolton, Scott; Connerney, Jack; Levin, Steve

    2017-04-01

    The Juno spacecraft's polar orbit provides an exceptional opportunity to study auroral processes in the largest and most dynamic auroral region in the solar system. The Jupiter Energetic particle Detector Instruments (JEDI) have SSD telescopes with multiple look directions and additional time-of-flight capabilities to measure ions and electrons from 6 keV to 20 MeV. These instruments resolve major ion species beginning at 30 keV/n, with coarser mass resolution for lower energy ions. JEDI instruments observed energetic heavy ions up to 20 MeV precipitating into the auroral regions during the first few Juno perijoves that have occurred to date. The observed heavy ion intensity was lower than expected, but composition of the precipitating ions included the predicted species oxygen and sulfur. During the first perijove pass, an unexpected element was observed with an atomic mass between oxygen and sulfur with intensity comparable to the other heavy ions. Preliminary analysis of the JEDI composition data indicates magnesium, with an unexpected energy spectrum beginning around 500 keV and extending up through 20 MeV. During the third perijove pass no significant intensity of energetic magnesium was observed, which suggests that the source of this element is intermittent. We report on the new findings of energetic heavy ions from the first few Juno orbits including the auroral regions, observations through closest approach, and discuss possible source mechanisms for the unexpected and transient observation of heavy ions.

  8. Alkylsulfonates as probes of uncoupling protein transport mechanism. Ion pair transport demonstrates that direct H(+) translocation by UCP1 is not necessary for uncoupling

    Czech Academy of Sciences Publication Activity Database

    Jabůrek, M.; Vařecha, M.; Ježek, Petr; Garlid, K. D.

    2001-01-01

    Roč. 276, č. 34 (2001), s. 31897-31905 ISSN 0021-9258 R&D Projects: GA AV ČR IAA5011106 Grant - others:NIH(US) DK56273 Institutional research plan: CEZ:AV0Z5011922 Keywords : mitochondrial uncoupling proteins * alkylsulfonates * ion pair transport Subject RIV: CE - Biochemistry Impact factor: 7.258, year: 2001

  9. Real-time orbit feedback at the APS

    International Nuclear Information System (INIS)

    Carwardine, J.

    1998-01-01

    A real-time orbit feedback system has been implemented at the Advanced Photon Source in order to meet the stringent orbit stability requirements. The system reduces global orbit motion below 30Hz by a factor of four to below 5 microm rms horizontally and 2 microm rms vertically. This paper focuses on dynamic orbit stability and describes the all-digital orbit feedback system that has been implemented at the APS. Implementation of the global orbit feedback system is described and its latest performance is presented. Ultimately, the system will provide local feedback at each x-ray source point using installed photon BPMs to measure x-ray beam position and angle directly. Technical challenges associated with local feedback and with dynamics of the associated corrector magnets are described. The unique diagnostic capabilities provided by the APS system are discussed with reference to their use in identifying sources of the underlying orbit motion

  10. Binding Affinity of a Highly Sensitive Au/Ag/Au/Chitosan-Graphene Oxide Sensor Based on Direct Detection of Pb2+ and Hg2+ Ions

    Directory of Open Access Journals (Sweden)

    Nur Hasiba Kamaruddin

    2017-10-01

    Full Text Available The study of binding affinity is essential in surface plasmon resonance (SPR sensing because it allows researchers to quantify the affinity between the analyte and immobilised ligands of an SPR sensor. In this study, we demonstrate the derivation of the binding affinity constant, K, for Pb2+ and Hg2+ ions according to their SPR response using a gold/silver/gold/chitosan–graphene oxide (Au/Ag/Au/CS–GO sensor for the concentration range of 0.1–5 ppm. The higher affinity of Pb2+ to binding with the CS–GO sensor explains the outstanding sensitivity of 2.05 °ppm−1 against 1.66 °ppm−1 of Hg2+. The maximum signal-to-noise ratio (SNR upon detection of Pb2+ is 1.53, and exceeds the suggested logical criterion of an SNR. The Au/Ag/Au/CS–GO SPR sensor also exhibits excellent repeatability in Pb2+ due to the strong bond between its functional groups and this cation. The adsorption data of Pb2+ and Hg2+ on the CS–GO sensor fits well with the Langmuir isotherm model where the affinity constant, K, of Pb2+ and Hg2+ ions is computed. The affinity of Pb2+ ions to the Au/Ag/Au/CS–GO sensor is significantly higher than that of Hg2+ based on the value of K, 7 × 105 M−1 and 4 × 105 M−1, respectively. The higher shift in SPR angles due to Pb2+ and Hg2+ compared to Cr3+, Cu2+ and Zn2+ ions also reveals the greater affinity of the CS–GO SPR sensor to them, thus supporting the rationale for obtaining K for these two heavy metals. This study provides a better understanding on the sensing performance of such sensors in detecting heavy metal ions.

  11. Voyager 1: energetic ions and electrons in the jovian magnetosphere.

    Science.gov (United States)

    Vogt, R E; Cook, W R; Cummings, A C; Garrard, T L; Gehrels, N; Stone, E C; Trainor, J H; Schardt, A W; Conlon, T; Lal, N; McDonald, F B

    1979-06-01

    The observations of the cosmic-ray subsystem have added significantly to our knowledge of Jupiter's magnetosphere. The most surprising result is the existence of energetic sulfur, sodium, and oxygen nuclei with energies above 7 megaelectron volts per nucleon which were found inside of Io's orbit. Also, significant fluxes of similarly energetic ions reflecting solar cosmic-ray composition were observed throughout the magnetosphere beyond 11 times the radius of Jupiter. It was also found that energetic protons are enhanced by 30 to 70 percent in the active hemisphere. Finally, the first observations were made of the magnetospheric tail in the dawn direction out to 160 Jupiter radii.

  12. An ion synchrotron design program

    International Nuclear Information System (INIS)

    Yoshida, Katsuhisa; Ishi, Yoshihiro

    1995-01-01

    Ion synchrotrons have promising applications in medical and other commercial settings as well as in physics research. Mitsubishi Electric has developed a program to facilitate efficiency studies on processes such as ion injection, radio-frequency capture and acceleration, and beam extraction. The integration method used in the particle-orbit calculations maintains the symplectic characteristic of Hamilton dynamics making it possible to simulate long-term phenomena reliably. The article introduces this program and several of its applications. (author)

  13. Orbital Order in Two-Orbital Hubbard Model

    Science.gov (United States)

    Honkawa, Kojiro; Onari, Seiichiro

    2018-03-01

    In strongly correlated multiorbital systems, various ordered phases appear. In particular, the orbital order in iron-based superconductors attracts much attention since it is considered to be the origin of the nematic state. To clarify the essential conditions for realizing orbital orders, we study the simple two-orbital (dxz,dyz) Hubbard model. We find that the orbital order, which corresponds to the nematic order, appears due to the vertex corrections even in the two-orbital model. Thus, the dxy orbital is not essential to realize the nematic orbital order. The obtained orbital order is determined by the orbital dependence and the topology of Fermi surfaces. We also find that another type of orbital order, which is rotated 45°, appears in a heavily hole-doped case.

  14. Proton spin tracking with symplectic integration of orbit motion

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Dutheil, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-05-03

    Symplectic integration had been adopted for orbital motion tracking in code SimTrack. SimTrack has been extensively used for dynamic aperture calculation with beam-beam interaction for the Relativistic Heavy Ion Collider (RHIC). Recently proton spin tracking has been implemented on top of symplectic orbital motion in this code. In this article, we will explain the implementation of spin motion based on Thomas-BMT equation, and the benchmarking with other spin tracking codes currently used for RHIC. Examples to calculate spin closed orbit and spin tunes are presented too.

  15. Penetrating orbital trauma by stiletto causing complex cranial neuropathies

    OpenAIRE

    Cleary, G; Nischal, K K; Jones, C A

    2006-01-01

    Penetrating orbital injuries pose a serious threat to vision, ocular motility, and in some cases, life. Long, sharp stiletto objects may penetrate deeply, causing catastrophic damage to orbital structures, despite seemingly trivial entry wounds. The authors present two cases of penetrating orbital injuries by stiletto objects, both entering via small eyelid wounds. Traumatic optic neuropathy occurred in both cases, and was treated with corticosteroids, however the globes escaped direct injury...

  16. Thermospheric mass density measurement from precise orbit ephemeris

    OpenAIRE

    Junyu Chen; Jizhang Sang

    2016-01-01

    Atmospheric drag, which can be inferred from orbit information of low-Earth orbiting (LEO) satellites, provides a direct means of measuring mass density. The temporal resolution of derived mass density could be in the range from minutes to days, depending on the precision of the satellite orbit data. This paper presents two methods potentially being able to estimate thermosphere mass density from precise obit ephemeris with high temporal resolution. One method is based on the drag perturbatio...

  17. Evolutionary algorithms to optimize low-thrust trajectory design in spacecraft orbital precession mission

    OpenAIRE

    Shirazi A.; Ceberio J.; Lozano J.A.

    2017-01-01

    In space environment, perturbations make the spacecraft lose its predefined orbit in space. One of these undesirable changes is the in-plane rotation of space orbit, denominated as orbital precession. To overcome this problem, one option is to correct the orbit direction by employing low-thrust trajectories. However, in addition to the orbital perturbation acting on the spacecraft, a number of parameters related to the spacecraft and its propulsion system must be optimized. This article lays ...

  18. Lithium-ion batteries

    CERN Document Server

    Yoshio, Masaki; Kozawa, Akiya

    2010-01-01

    This book is a compilation of up-to-date information relative to Li-Ion technology. It provides the reader with a single source covering all important aspects of Li-Ion battery operations. It fills the gap between the old original Li-Ion technology and present state of the technology that has developed into a high state of practice. The book is designed to provide a single source for an up-to-date description of the technology associated with the Li-Ion battery industry. It will be useful to researchers interested in energy conversion for the direct conversion of chemical energy into electrica

  19. Doppler ion program description

    International Nuclear Information System (INIS)

    Henline, P.

    1980-12-01

    The Doppler spectrometer is a conventional Czerny-Turner grating spectrometer with a 1024 channel multiple detector. Light is dispersed across the detector, and its output yields a spectrum covering approximately 200 A. The width of the spectral peak is directly proportional to the temperature of the emitting ions, and determination of the impurity ion temperature allows one to infer the plasma ion temperature. The Doppler ion software system developed at General Atomic uses a TRACOR Northern 1710-31 and an LSI-11/2. The exact configuration of Doublet III is different from TRACOR Northern systems at other facilities

  20. The orbital record in stratigraphy

    Science.gov (United States)

    Fischer, Alfred G.

    1992-01-01

    , and (2) presence of abundant microfossils yields close ties to geochronology. A tantalizing possibility that stratigraphy may yield a record of orbital signals unrelated to climate has turned up in magnetic studies of our Cretaceous core. Magnetic secular variations here carry a strong 39 ka periodicity, corresponding to the theoretical obliquity period of that time - Does the obliquity cycle perhaps have some direct influence on the magnetic field?

  1. Extended duration orbiter (EDO) insignia

    Science.gov (United States)

    1990-01-01

    Extended duration orbiter (EDO) insignia incorporates a space shuttle orbiter with payload bay doors (PLBDs) open and a spacelab module inside. Trailing the orbiter are the initials EDO. The EDO-modified Columbia, Orbiter Vehicle (OV) 102, will be flown for the first EDO mission, STS-50.

  2. Elliptical Orbit Performance Computer Program

    Science.gov (United States)

    Myler, T.

    1984-01-01

    Elliptical Orbit Performance (ELOPE) computer program for analyzing orbital performance of space boosters uses orbit insertion data obtained from trajectory simulation to generate parametric data on apogee and perigee altitudes as function of payload data. Data used to generate presentation plots that display elliptical orbit performance capability of space booster.

  3. PREDICT: Satellite tracking and orbital prediction

    Science.gov (United States)

    Magliacane, John A.

    2011-12-01

    PREDICT is an open-source, multi-user satellite tracking and orbital prediction program written under the Linux operating system. PREDICT provides real-time satellite tracking and orbital prediction information to users and client applications through: the system console the command line a network socket the generation of audio speechData such as a spacecraft's sub-satellite point, azimuth and elevation headings, Doppler shift, path loss, slant range, orbital altitude, orbital velocity, footprint diameter, orbital phase (mean anomaly), squint angle, eclipse depth, the time and date of the next AOS (or LOS of the current pass), orbit number, and sunlight and visibility information are provided on a real-time basis. PREDICT can also track (or predict the position of) the Sun and Moon. PREDICT has the ability to control AZ/EL antenna rotators to maintain accurate orientation in the direction of communication satellites. As an aid in locating and tracking satellites through optical means, PREDICT can articulate tracking coordinates and visibility information as plain speech.

  4. Theory of Orbital Magnetization in Solids

    Science.gov (United States)

    Thonhauser, T.

    In this review article, we survey the relatively new theory of orbital magnetization in solids — often referred to as the "modern theory of orbital magnetization" — and its applications. Surprisingly, while the calculation of the orbital magnetization in finite systems such as atoms and molecules is straight forward, in extended systems or solids it has long eluded calculations owing to the fact that the position operator is ill-defined in such a context. Approaches that overcome this problem were first developed in 2005 and in the first part of this review we present the main ideas reaching from a Wannier function approach to semi-classical and finite-temperature formalisms. In the second part, we describe practical aspects of calculating the orbital magnetization, such as taking k-space derivatives, a formalism for pseudopotentials, a single k-point derivation, a Wannier interpolation scheme, and DFT specific aspects. We then show results of recent calculations on Fe, Co, and Ni. In the last part of this review, we focus on direct applications of the orbital magnetization. In particular, we will review how properties such as the nuclear magnetic resonance shielding tensor and the electron paramagnetic resonance g-tensor can be elegantly calculated in terms of a derivative of the orbital magnetization.

  5. EIVAN - AN INTERACTIVE ORBITAL TRAJECTORY PLANNING TOOL

    Science.gov (United States)

    Brody, A. R.

    1994-01-01

    The Interactive Orbital Trajectory planning Tool, EIVAN, is a forward looking interactive orbit trajectory plotting tool for use with Proximity Operations (operations occurring within a one kilometer sphere of the space station) and other maneuvers. The result of vehicle burns on-orbit is very difficult to anticipate because of non-linearities in the equations of motion governing orbiting bodies. EIVAN was developed to plot resulting trajectories, to provide a better comprehension of orbital mechanics effects, and to help the user develop heuristics for onorbit mission planning. EIVAN comprises a worksheet and a chart from Microsoft Excel on a Macintosh computer. The orbital path for a user-specified time interval is plotted given operator burn inputs. Fuel use is also calculated. After the thrust parameters (magnitude, direction, and time) are input, EIVAN plots the resulting trajectory. Up to five burns may be inserted at any time in the mission. Twenty data points are plotted for each burn and the time interval can be varied to accommodate any desired time frame or degree of resolution. Since the number of data points for each burn is constant, the mission duration can be increased or decreased by increasing or decreasing the time interval. The EIVAN program runs with Microsoft's Excel for execution on a Macintosh running Macintosh OS. A working knowledge of Excel is helpful, but not imperative, for interacting with EIVAN. The program was developed in 1989.

  6. Dynamics of alkali ions-neutral molecules reactions: Radio frequency-guided beam experimental cross-sections and direct quasiclassical trajectory studies

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar, J.; Andres, J. de; Lucas, J. M.; Alberti, M.; Huarte-Larranaga, F.; Bassi, D.; Aguilar, A. [Departament de Quimica Fisica, Institut de Quimica Teorica i Computacional (IQTCUB), Universitat de Barcelona, Marti i Franques, 1, 08028 Barcelona (Spain); Dipartimento di Fisica, Universita degli Studi di Trento, 38123 Povo-Trento (Italy); Departament de Quimica Fisica, Institut de Quimica Teorica i Computacional (IQTCUB), Universitat de Barcelona, Marti i Franques, 1, 08028 Barcelona (Spain)

    2012-11-27

    Different reactive processes taking place in collisions between alkali ions and neutral i-C{sub 3}H{sub 7}Cl molecules in the low (center of mass frame) energy range have been studied using an octopole radiofrequency guided-ion-beam apparatus developed in our laboratory. Cross-section energy dependences for all these reactions have been obtained in absolute units. Ab initio electronic structure calculations for those colliding systems evolving on the ground single potential surface have given relevant information on the main topological features of the surfaces. For some of the reactions a dynamic study by 'on the fly' trajectories has complemented the available experimental and electronic structure information.

  7. Matrix assisted ionization: new aromatic and nonaromatic matrix compounds producing multiply charged lipid, peptide, and protein ions in the positive and negative mode observed directly from surfaces.

    Science.gov (United States)

    Li, Jing; Inutan, Ellen D; Wang, Beixi; Lietz, Christopher B; Green, Daniel R; Manly, Cory D; Richards, Alicia L; Marshall, Darrell D; Lingenfelter, Steven; Ren, Yue; Trimpin, Sarah

    2012-10-01

    Matrix assisted inlet ionization (MAII) is a method in which a matrix:analyte mixture produces mass spectra nearly identical to electrospray ionization without the application of a voltage or the use of a laser as is required in laserspray ionization (LSI), a subset of MAII. In MAII, the sample is introduced by, for example, tapping particles of dried matrix:analyte into the inlet of the mass spectrometer and, therefore, permits the study of conditions pertinent to the formation of multiply charged ions without the need of absorption at a laser wavelength. Crucial for the production of highly charged ions are desolvation conditions to remove matrix molecules from charged matrix:analyte clusters. Important factors affecting desolvation include heat, vacuum, collisions with gases and surfaces, and even radio frequency fields. Other parameters affecting multiply charged ion production is sample preparation, including pH and solvent composition. Here, findings from over 100 compounds found to produce multiply charged analyte ions using MAII with the inlet tube set at 450 °C are presented. Of the compounds tested, many have -OH or -NH(2) functionality, but several have neither (e.g., anthracene), nor aromaticity or conjugation. Binary matrices are shown to be applicable for LSI and solvent-free sample preparation can be applied to solubility restricted compounds, and matrix compounds too volatile to allow drying from common solvents. Our findings suggest that the physical properties of the matrix such as its morphology after evaporation of the solvent, its propensity to evaporate/sublime, and its acidity are more important than its structure and functional groups.

  8. Matrix Assisted Ionization: New Aromatic and Nonaromatic Matrix Compounds Producing Multiply Charged Lipid, Peptide, and Protein Ions in the Positive and Negative Mode Observed Directly from Surfaces

    Science.gov (United States)

    Li, Jing; Inutan, Ellen D.; Wang, Beixi; Lietz, Christopher B.; Green, Daniel R.; Manly, Cory D.; Richards, Alicia L.; Marshall, Darrell D.; Lingenfelter, Steven; Ren, Yue; Trimpin, Sarah

    2012-10-01

    Matrix assisted inlet ionization (MAII) is a method in which a matrix:analyte mixture produces mass spectra nearly identical to electrospray ionization without the application of a voltage or the use of a laser as is required in laserspray ionization (LSI), a subset of MAII. In MAII, the sample is introduced by, for example, tapping particles of dried matrix:analyte into the inlet of the mass spectrometer and, therefore, permits the study of conditions pertinent to the formation of multiply charged ions without the need of absorption at a laser wavelength. Crucial for the production of highly charged ions are desolvation conditions to remove matrix molecules from charged matrix:analyte clusters. Important factors affecting desolvation include heat, vacuum, collisions with gases and surfaces, and even radio frequency fields. Other parameters affecting multiply charged ion production is sample preparation, including pH and solvent composition. Here, findings from over 100 compounds found to produce multiply charged analyte ions using MAII with the inlet tube set at 450 °C are presented. Of the compounds tested, many have -OH or -NH2 functionality, but several have neither (e.g., anthracene), nor aromaticity or conjugation. Binary matrices are shown to be applicable for LSI and solvent-free sample preparation can be applied to solubility restricted compounds, and matrix compounds too volatile to allow drying from common solvents. Our findings suggest that the physical properties of the matrix such as its morphology after evaporation of the solvent, its propensity to evaporate/sublime, and its acidity are more important than its structure and functional groups.

  9. An HFB scheme in natural orbitals

    International Nuclear Information System (INIS)

    Reinhard, P.G.; Rutz, K.; Maruhn, J.A.

    1997-01-01

    We present a formulation of the Hartree-Fock-Bogoliubov (HFB) equations which solves the problem directly in the basis of natural orbitals. This provides a very efficient scheme which is particularly suited for large scale calculations on coordinate-space grids. (orig.)

  10. Third-generation muffin–tin orbitals

    Indian Academy of Sciences (India)

    Unknown

    ↑↓) with z referring to the local z- direction of the molecule. This example immediately leads to a treatment of open-shell systems by means of spin and possibly orbital polarizations. We have seen that the 3rd-generation MTO method offers ...

  11. Orbital lymphoid tumors

    International Nuclear Information System (INIS)

    Matsumoto, Hiroko; Ueno, Hisayuki

    1994-01-01

    We examined 13 cases of orbital lymphoid tumors (OLT) and 1 of orbital hemangioma (OH), using dynamic MRI, to determine the biological behavior of the tumors before surgery. We measured time-dependent changes in the contrast enhancement of tumors and described time intensity curves (TIC), dividing the cases into 3 architectural types: completes septum (CS), incomplete septum (IS), and diffuse types. The TICs of reactive lymphoid hyperplasia (RLH, 2 cases) of CS type and idiopathic orbital inflamation (1), RLH (5) of IS type, atypical lymphoid hyperplasia (4), and malignant lymphoma (1) and OH (1) showed rapid increase with low peak and gradual decrease, rapid increase with high peak and gradual decrease, rapid increase and plateau, and gradual increase type, respectively. In order words, OLT showed various TIC, roughly correlating with pathological findings. These results indicate that dynamic MRI may be useful in the preoperative clinical diagnosis of OLT. (author)

  12. [Secondary orbital lymphoma].

    Science.gov (United States)

    Basanta, I; Sevillano, C; Álvarez, M D

    2015-09-01

    A case is presented of an 85 year-old Caucasian female with lymphoma that recurred in the orbit (secondary ocular adnexal lymphoma). The orbital tumour was a diffuse large B-cell lymphoma according to the REAL classification (Revised European-American Lymphoma Classification). Orbital lymphomas are predominantly B-cell proliferations of a variety of histological types, and most are low-grade tumours. Patients are usually middle-aged or elderly, and it is slightly more common in women. A palpable mass, proptosis and blepharoptosis are the most common signs of presentation. Copyright © 2011 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  13. Preseptal Cellulitis Or Orbital Cellulitis?

    Science.gov (United States)

    Lim, L T; Miller, D; Ah-Kee, E Y; Ferguson, A

    2015-06-29

    Preseptal cellulitis and orbital cellulitis can both present with increasing swelling, tenderness and redness around the eye, but their management differs. Preseptal cellulitis is more common and much less aggressive than orbital cellulitis. In contrast, orbital cellulitis is a medical emergency requiring urgent management. In this article, we provide a systematic approach to distinguish between preseptal cellulitis and orbital cellulitis at presentation, as the distinction between the two entities and the prompt recognition of orbital cellulitis can be potentially life-saving.

  14. Direct Drive Hall Thruster System Development

    Science.gov (United States)

    Hoskins, W. Andrew; Homiak, Daniel; Cassady, R. Joseph; Kerslake, Tom; Peterson, Todd; Ferguson, Dale; Snyder, Dave; Mikellides, Ioannis; Jongeward, Gary; Schneider, Todd

    2003-01-01

    The sta:us of development of a Direct Drive Ha!! Thruster System is presented. 13 the first part. a s:udy of the impacts to spacecraft systems and mass benefits of a direct-drive architecture is reviewed. The study initially examines four cases of SPT-100 and BPT-4000 Hall thrusters used for north-south station keeping on an EXPRESS-like geosynchronous spacecraft and for primary propulsion for a Deep Space- 1 based science spacecraft. The study is also extended the impact of direct drive on orbit raising for higher power geosynchronous spacecraft and on other deep space missions as a function of power and delta velocity. The major system considerations for accommodating a direct drive Hall thruster are discussed, including array regulation, system grounding, distribution of power to the spacecraft bus, and interactions between current-voltage characteristics for the arrays and thrusters. The mass benefit analysis shows that, for the initial cases, up to 42 kg of dry mass savings is attributable directly to changes in the propulsion hardware. When projected mass impacts of operating the arrays and the electric power system at 300V are included, up to 63 kg is saved for the four initial cases. Adoption of high voltage lithium ion battery technology is projected to further improve these savings. Orbit raising of higher powered geosynchronous spacecraft, is the mission for which direct drive provides the most benefit, allowing higher efficiency electric orbit raising to be accomplished in a limited period of time, as well as nearly eliminating significant power processing heat rejection mass. The total increase in useful payload to orbit ranges up to 278 kg for a 25 kW spacecraft, launched from an Atlas IIA. For deep space missions, direct drive is found to be most applicable to higher power missions with delta velocities up to several km/s , typical of several Discovery-class missions. In the second part, the status of development of direct drive propulsion power

  15. Low-altitude ion heating with downflowing and upflowing ions

    Science.gov (United States)

    Shen, Y.; Knudsen, D. J.; Burchill, J. K.; Howarth, A. D.; Yau, A. W.; James, G.; Miles, D.; Cogger, L. L.; Perry, G. W.

    2017-12-01

    Mechanisms that energize ions at the initial stage of ion upflow are still not well understood. We statistically investigate ionospheric ion energization and field-aligned motion at very low altitudes (330-730 km) using simultaneous plasma, magnetic field, wave electric field and optical data from the e-POP satellite. The high-time-resolution (10 ms) dataset enables us to study the micro-structures of ion heating and field-aligned ion motion. The ion temperature and field-aligned bulk flow velocity are derived from 2-D ion distribution functions measured by the SEI instrument. From March 2015 to March 2016, we've found 17 orbits (in total 24 ion heating periods) with clear ion heating signatures passing across the dayside cleft or the nightside auroral regions. Most of these events have consistent ion heating and flow velocity characteristics observed from both the SEI and IRM instruments. The perpendicular ion temperature goes up to 4.5 eV within a 2 km-wide region in some cases, in which the Radio Receiver Instrument (RRI) sees broadband extremely low frequency (BBELF) waves, demonstrating significant wave-ion heating down to as low as 350 km. The e-POP Fast Auroral Imager (FAI) and Magnetic Field (MGF) instruments show that many events are associated with active aurora and are within downward current regions. Contrary to what would be expected from mirror-force acceleration of heated ions, the majority of these heating events (17 out of 24) are associated with the core ion downflow rather than upflow. These statistical results provide us with new sights into ion heating and field-aligned flow processes at very low altitudes.

  16. Fundamental methods to measure the orbital angular momentum of light

    NARCIS (Netherlands)

    Berkhout, Gregorius Cornelis Gerardus (Joris)

    2011-01-01

    Light is a ubiquitous carrier of information. This information can be encoded in the intensity, direction, frequency and polarisation of the light and, which was described more recently, in its orbital angular momentum. Although creating light beams with orbital angular momentum is relatively easy,

  17. An inline ion-exchange system in a chemiluminescence-based analyzer for direct analysis of N-nitrosamines in treated wastewater.

    Science.gov (United States)

    Kodamatani, Hitoshi; Roback, Shannon L; Plumlee, Megan H; Ishida, Kenneth P; Masunaga, Hiroto; Maruyama, Noboru; Fujioka, Takahiro

    2018-04-13

    A newly developed, ion exchange-based inline pretreatment system was used to mitigate the effect of background constituents in natural water and treated wastewater to achieve rapid, reliable, and sensitive analysis of N-nitrosamines. The pretreatment system (anion exchange module, AEM) was incorporated into a high-performance liquid chromatograph (HPLC) coupled with a photochemical reactor (PR) and chemiluminescence (CL) detector (HPLC-PR-CL), which can analyze four hydrophilic N-nitrosamines at ng/L levels. This system requires no pre-concentration of the water sample nor the use of deuterated surrogates, unlike other conventional N-nitrosamine analytical techniques. The AEM converted anions in the eluent to hydroxide ions after HPLC separation and increased eluent pH, allowing for the subsequent photochemical reactions, which are otherwise achieved by pH conditioning with an additional dosing pump of basic chemical. The AEM also removed anionic interfering compounds (e.g. nitrate) from the samples, allowing for improved N-nitrosamine analysis in treated wastewater. The operating conditions of the AEM and PR were optimized to obtain sensitive and stable analytical performance. As a result, the lowest-concentration minimum reporting levels of N-nitrosodimethylamine, N-nitrosomorpholine, N-nitrosomethylethylamine, and N- nitrosopyrrolidine using the optimized system were 0.42, 0.54, 0.58, and 1.4 ng/L, respectively. The improved analytical method was validated by comparing the results with a conventional method based on gas chromatography coupled with a mass spectrometric ion trap detector. These results indicated that HPLC-PR-CL equipped with an inline AEM can be competitively applied as a rapid analytical technique for the determination of N-nitrosamines in various water matrices. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Dawn Orbit Determination Team: Trajectory Modeling and Reconstruction Processes at Vesta

    Science.gov (United States)

    Abrahamson, Matthew J.; Ardito, Alessandro; Han, Dongsuk; Haw, Robert; Kennedy, Brian; Mastrodemos, Nick; Nandi, Sumita; Park, Ryan; Rush, Brian; Vaughan, Andrew

    2013-01-01

    The Dawn spacecraft spent over a year in orbit around Vesta from July 2011 through August 2012. In order to maintain the designated science reference orbits and enable the transfers between those orbits, precise and timely orbit determination was required. Challenges included low-thrust ion propulsion modeling, estimation of relatively unknown Vesta gravity and rotation models, track-ing data limitations, incorporation of real-time telemetry into dynamics model updates, and rapid maneuver design cycles during transfers. This paper discusses the dynamics models, filter configuration, and data processing implemented to deliver a rapid orbit determination capability to the Dawn project.

  19. Three-body Coulomb effects in the direct Coulomb breakup of 8B into 7Be + p in the field of a 208Pb ion

    International Nuclear Information System (INIS)

    Irgaziev, B.F.; Alt, E.O.; Mukhamedzhanov, A.M.

    1999-01-01

    The amplitude for the Coulomb breakup of a light nucleus in the field of a highly charged ion is considered in the framework of the distorted wave approach, with particular emphasis being laid on correctly taking into account the three-body Coulomb interactions in the final state. Numerical calculations have been performed for the double differential cross section for the reaction 208 Pb( 8 B, 7 Be p) 208 Pb. They clearly demonstrate the importance of long-range three-body Coulomb correlations in the astrophysically interesting regime when the ejectiles have extremely small relative energies. Refs. 9 (author)

  20. Transfer and capture into distant retrograde orbits

    Science.gov (United States)

    Scott, Christopher J.

    collision orbits within the highly chaotic region commonly recognized as a saddle point on the energy manifold. The pragmatic techniques derived from this analysis solve a number of complications apparent in the literature. Notably a reliable methodology for the construction of an arbitrary number of transfer orbits circumvents the requirement of computing specialized periodic orbits or extensive numerical sampling of the phase space. The procedure provides a complete description of the design space accessing a wide range of distant retrograde orbits sizes, insertion points, and parking orbit altitudes in an automated manner. The transfers are studied in a similar fashion to periodic orbits unveiling the intimate relationship among design parameters and phase space structure. An arbitrary number of Earth return periodic orbits can be generated as a by-product. These orbits may be useful for spacecraft that must make a number of passes near the second primary without a reduction in energy. Further analysis of the lobe dynamics and a modification of the transfers to the center of the stable region yields sets of single impulse transfers to sticky distant retrograde orbits. It is shown that the evolution of the phase space structures with energy corresponds to the variation of capture time and target size. Capture phenomenon is related to the stability characteristics of the unstable periodic orbit and the geometry of the corresponding homoclinic tangle at various energies. Future spacecraft with little or no propulsive means may take advantage of these natural trajectories for operations in the region. Temporary capture along a sticky orbit may come before incremental stabilization of the spacecraft by way of a series of small impulsive or a low continuous thrust maneuvers. The requirements of small stabilization maneuver are calculated and compared to a direct transfer to the center of stable region. This mission design may be desirable as any failure in the classic set of

  1. Sentinel-1A - First precise orbit determination results

    Science.gov (United States)

    Peter, H.; Jäggi, A.; Fernández, J.; Escobar, D.; Ayuga, F.; Arnold, D.; Wermuth, M.; Hackel, S.; Otten, M.; Simons, W.; Visser, P.; Hugentobler, U.; Féménias, P.

    2017-09-01

    Sentinel-1A is the first satellite of the European Copernicus programme. Equipped with a Synthetic Aperture Radar (SAR) instrument the satellite was launched on April 3, 2014. Operational since October 2014 the satellite delivers valuable data for more than two years. The orbit accuracy requirements are given as 5 cm in 3D. In order to fulfill this stringent requirement the precise orbit determination (POD) is based on the dual-frequency GPS observations delivered by an eight-channel GPS receiver. The Copernicus POD (CPOD) Service is in charge of providing the orbital and auxiliary products required by the PDGS (Payload Data Ground Segment). External orbit validation is regularly performed by comparing the CPOD Service orbits to orbit solutions provided by POD expert members of the Copernicus POD Quality Working Group (QWG). The orbit comparisons revealed systematic orbit offsets mainly in radial direction (approx. 3 cm). Although no independent observation technique (e.g. DORIS, SLR) is available to validate the GPS-derived orbit solutions, comparisons between the different antenna phase center variations and different reduced-dynamic orbit determination approaches used in the various software packages helped to detect the cause of the systematic offset. An error in the given geometry information about the satellite has been found. After correction of the geometry the orbit validation shows a significant reduction of the radial offset to below 5 mm. The 5 cm orbit accuracy requirement in 3D is fulfilled according to the results of the orbit comparisons between the different orbit solutions from the QWG.

  2. Myxoma of the orbit.

    Directory of Open Access Journals (Sweden)

    Rambhatla Saptagirish

    2003-01-01

    Full Text Available Myxomas are rare, benign neoplasms of mesenchymal origin that usually develop in soft tissues. As the clinical manifestations are non-specific, it is difficult to diagnose the tumour without biopsy and histopathological examination. We report a case of orbital myxoma with histopathological correlation.

  3. The Lunar orbit paradox

    Directory of Open Access Journals (Sweden)

    Tomić Aleksandar S.

    2013-01-01

    Full Text Available Newton's formula for gravity force gives greather force intensity for atraction of the Moon by the Sun than atraction by the Earth. However, central body in lunar (primary orbit is the Earth. So appeared paradox which were ignored from competent specialist, because the most important problem, determination of lunar orbit, was inmediately solved sufficiently by mathematical ingeniosity - introducing the Sun as dominant body in the three body system by Delaunay, 1860. On this way the lunar orbit paradox were not canceled. Vujičić made a owerview of principles of mechanics in year 1998, in critical consideration. As an example for application of corrected procedure he was obtained gravity law in some different form, which gave possibility to cancel paradox of lunar orbit. The formula of Vujičić, with our small adaptation, content two type of acceleration - related to inertial mass and related to gravity mass. So appears carried information on the origin of the Moon, and paradox cancels.

  4. 11. Deadly Orbital Mucormycosis

    African Journals Online (AJOL)

    Sitwala

    medial recti muscles. The conclusion reached was orbital pseudo-tumour RE with a differential diagnosis of lymphoma. The CT Scan film below shows the retro-bulbar tumour described in the report. Other investigations done were fasting Blood Sugar which was ... thrombosis and death of surrounding tissue by loss. 6.

  5. Influence of the Mercury gravity field on the orbit insertion strategy of BepiColombo

    Science.gov (United States)

    Schuster, Anja; Jehn, Rüdiger

    2013-04-01

    Ziel des Versuchs BepiColombo is Europe's first mission to Mercury expected to launch on an Ariane 5 rocket in 2015. The European Space Agency (ESA), in cooperation with the Japan Aerospace Exploration Agency (JAXA), is responsible for the mission design and navigation. The mission has a high scientific interest as there are still many unsolved questions about Mercury, such as origin and evolution of the planet, its physical form, as well as its interior structure. Also instruments to measure the chemical composition, the exosphere and magnetosphere of Mercury will be on board of BepiColombo. The interplanetary journey based on ion propulsion and 7 gravity assists is followed by the challenging gravitational capture at Mercury. This paper describes the manoeuvre sequences of the Mercury Orbit Insertion (MOI). The manoeuvres were optimized such that the two scientific elements - the Mercury Magnetospheric Orbiter (MMO) and the Mercury Planetary Orbiter (MPO) - can be released to their target orbits with minimum fuel consumption. The MOI consists of fifteen burns: After five burns the MMO will be released to its operational orbit of 600 km x 11624 km; after the fifteenth burn MPO shall arrive at its target orbit of 560 km x 1530 km. The optimum burn sequence was obtained by implementing the optimization package SNOPT into an orbit propagation software that considers orbital perturbations due to the non-sphericity of Mercury and the gravitational pull of the Sun. Since the gravity field of Mercury is still not very well known - even after Messenger being in orbit around Mercury for almost two years - the final MPO orbit is still under discussion. Depending on the final choice of the MPO orbit, different orbit insertion sequences have to be optimised and the most probable ones are presented here. This also includes different argument of periherm values for MPO and MMO. Furthermore, the effect of the solar aspect angle constraints ("no direct Sun on MMO and on the

  6. Meteoroid Orbits from Observations

    Science.gov (United States)

    Campbell-Brown, Margaret

    2018-04-01

    Millions of orbits of meteoroids have been measured over the last few decades, and they comprise the largest sample of orbits of solar system bodies which exists. The orbits of these objects can shed light on the distribution and evolution of comets and asteroids in near-Earth space (e.g. Neslusan et al. 2016). If orbits can be measured at sufficiently high resolution, individual meteoroids can be traced back to their parent bodies and, in principle, even to their ejection time (Rudawska et al. 2012). Orbits can be measured with multi-station optical observations or with radar observations.The most fundamental measured quantities are the speed of the meteor and the two angles of the radiant, or point in the sky from which the meteor appears to come. There are many methods used to determine these from observations, but not all produce the most accurate results (Egal et al. 2017). These three measured quantities, along with the time and location of the observation, are sufficient to obtain an orbit (see, e.g., Clark & Wiegert 2011), but the measurements must be corrected for the deceleration of the meteoroid in the atmosphere before it was detected, the rotation of the Earth, and the gravitational attraction of the Earth (including higher order moments if great precision is necessary).Once meteor orbits have been determined, studies of the age and origin of meteor showers (Bruzzone et al., 2015), the parent bodies of sporadic sources (Pokorny et al. 2014), and the dynamics of the meteoroid complex as a whole can be constrained.Bruzzone, J. S., Brown, P., Weryk, R., Campbell-Brown, M., 2015. MNRAS 446, 1625.Clark, D., Wiegert, P., 2011. M&PS 46, 1217.Egal, A., Gural, P., Vaubaillon, J., Colas, F., Thuillot, W., 2017. Icarus 294, 43.Neslusan, L., Vaubaillon, J., Hajdukova, M., 2016. A&A 589, id.A100.Pokorny, P., Vokrouhlicky, D., Nesvorny, D., Campbell-Brown, M., Brown, P., 2014. ApJ 789, id.25.Rudawska, R., Vaubaillon, J., Atreya, P., 2012. A&A 541, id.A2

  7. Direct large-scale synthesis of 3D hierarchical mesoporous NiO microspheres as high-performance anode materials for lithium ion batteries.

    Science.gov (United States)

    bai, Zhongchao; Ju, Zhicheng; Guo, Chunli; Qian, Yitai; Tang, Bin; Xiong, Shenglin

    2014-03-21

    Hierarchically porous materials are an ideal material platform for constructing high performance Li-ion batteries (LIBs), offering great advantages such as large contact area between the electrode and the electrolyte, fast and flexible transport pathways for the electrolyte ions and the space for buffering the strain caused by repeated Li insertion/extraction. In this work, NiO microspheres with hierarchically porous structures have been synthesized via a facile thermal decomposition method by only using a simple precursor. The superstructures are composed of nanocrystals with high specific surface area, large pore volume, and broad pore size distribution. The electrochemical properties of 3D hierarchical mesoporous NiO microspheres were examined by cyclic voltammetry and galvanostatic charge-discharge studies. The results demonstrate that the as-prepared NiO nanospheres are excellent electrode materials in LIBs with high specific capacity, good retention and rate performance. The 3D hierarchical mesoporous NiO microspheres can retain a reversible capacity of 800.2 mA h g(-1) after 100 cycles at a high current density of 500 mA g(-1).

  8. Exit points, on plasma, of lost fast ions during NBI in TJ-II; Puntos de salida en el plasma de los iones rapidos durante NBI en el TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Guasp, J.

    1995-07-01

    The distribution of the exit points, on plasma border, for the lost fast ions during tangential balanced NBI in TJ-II helical axis Stellarator is theoretically analysed, as well for direct as for delayed losses. The link between, the position of those exit points and the corresponding at birth, orbits and drifts is analysed also. It is shown that such relation is rather independent of beam energy and plasma density and is mainly related to the magnetic configuration characteristics. This study is a needed intermediate step to the analysis of impacts of those ions on the vacuum vessel of TJ-II. (Author) 2 refs.

  9. Introducing the Moon's Orbital Eccentricity

    Science.gov (United States)

    Oostra, Benjamin

    2014-11-01

    I present a novel way to introduce the lunar orbital eccentricity in introductory astronomy courses. The Moon is perhaps the clearest illustration of the general orbital elements such as inclination, ascending node, eccentricity, perigee, and so on. Furthermore, I like the students to discover astronomical phenomena for themselves, by means of a guided exercise, rather than just telling them the facts.1 The inclination and nodes may be found by direct observation, monitoring carefully the position of the Moon among the stars. Even the regression of the nodes may be discovered in this way2 To find the eccentricity from students' observations is also possible,3 but that requires considerable time and effort. if a whole class should discover it in a short time, here is a method more suitable for a one-day class or home assignment. The level I aim at is, more or less, advanced high school or first-year college students. I assume them to be acquainted with celestial coordinates and the lunar phases, and to be able to use algebra and trigonometry.

  10. Maintaining Aura's Orbit Requirements While Performing Orbit Maintenance Maneuvers Containing an Orbit Normal Delta-V Component

    Science.gov (United States)

    Johnson, Megan R.; Petersen, Jeremy D.

    2014-01-01

    The Earth Observing System (EOS) Afternoon Constellation consists of five member missions (GCOM-W1, Aqua, CALIPSO, CloudSat, and Aura), each of which maintain a frozen, sun-synchronous orbit with a 16-day repeating ground track that follows the Worldwide Reference System-2 (WRS-2). Under nominal science operations for Aura, the propulsion system is oriented such that the resultant thrust vector is aligned 13.493 degrees away from the velocity vector along the yaw axis. When performing orbit maintenance maneuvers, the spacecraft performs a yaw slew to align the thrust vector in the appropriate direction. A new Drag Make Up (DMU) maneuver operations scheme has been implemented for Aura alleviating the need for the 13.493 degree yaw slew. The focus of this investigation is to assess the impact that no-slew DMU maneuver operations will have on Aura's Mean Local Time (MLT) which drives the required along track separation between Aura and the constellation members, as well as Aura's frozen orbit properties, eccentricity and argument of perigee. Seven maneuver strategies were analyzed to determine the best operational approach. A mirror pole strategy, with maneuvers alternating at the North and South poles, was implemented operationally to minimize impact to the MLT. Additional analysis determined that the mirror pole strategy could be further modified to include frozen orbit maneuvers and thus maintain both MLT and the frozen orbit properties under noslew operations.

  11. Magnus Effect on a Spinning Satellite in Low Earth Orbit

    Science.gov (United States)

    Ramjatan, Sahadeo; Fitz-Coy, Norman; Yew, Alvin Garwai

    2016-01-01

    A spinning body in a flow field generates an aerodynamic lift or Magnus effect that displaces the body in a direction normal to the freestream flow. Earth orbiting satellites with substantial body rotation in appreciable atmospheric densities may generate a Magnus force to perturb orbital dynamics. We investigate the feasibility of using this effect for spacecraft at a perigee of 80km using the Systems Tool Kit (STK). Results show that for a satellite of reasonable properties, the Magnus effect doubles the amount of time in orbit. Orbital decay was greatly mitigated for satellites spinning at 10000 and 15000RPM. This study demonstrates that the Magnus effect has the potential to sustain a spacecraft's orbit at a low perigee altitude and could also serve as an orbital maneuver capability.

  12. Effect of orbital symmetry on the anisotropic superexchange interaction

    International Nuclear Information System (INIS)

    Kim, Beom Hyun; Min, B I

    2011-01-01

    Employing the microscopic superexchange model incorporating the effect of spin-orbit interaction, we have investigated the Dzyaloshinsky-Moriya (DM) interaction in perovskite transition-metal (TM) oxides and explored the interplay between the DM interaction and the TM-3d orbital symmetry. For d 3 and d 5 systems with isotropic orbital symmetry, the DM vectors are well described by a simple symmetry analysis considering only the bond geometry. In contrast, the DM interaction for d 4 systems with anisotropic orbital symmetry shows slightly different behavior, which does not obey simple symmetry analysis. The direction as well as the strength of the DM vector varies depending on the occupied orbital shape. We have understood this behavior based on the orbital symmetry induced by local crystal field variation.

  13. Local orbitals by minimizing powers of the orbital variance

    DEFF Research Database (Denmark)

    Jansik, Branislav; Høst, Stinne; Kristensen, Kasper

    2011-01-01

    's correlation consistent basis sets, it is seen that for larger penalties, the virtual orbitals become more local than the occupied ones. We also show that the local virtual HF orbitals are significantly more local than the redundant projected atomic orbitals, which often have been used to span the virtual......It is demonstrated that a set of local orthonormal Hartree–Fock (HF) molecular orbitals can be obtained for both the occupied and virtual orbital spaces by minimizing powers of the orbital variance using the trust-region algorithm. For a power exponent equal to one, the Boys localization function...... be encountered. These disappear when the exponent is larger than one. For a small penalty, the occupied orbitals are more local than the virtual ones. When the penalty is increased, the locality of the occupied and virtual orbitals becomes similar. In fact, when increasing the cardinal number for Dunning...

  14. Rapid screening of abused drugs by direct analysis in real time (DART) coupled to time-of-flight mass spectrometry (TOF-MS) combined with ion mobility spectrometry (IMS).

    Science.gov (United States)

    Lian, Ru; Wu, Zhongping; Lv, Xiaobao; Rao, Yulan; Li, Haiyang; Li, Jinghua; Wang, Rong; Ni, Chunfang; Zhang, Yurong

    2017-10-01

    Increasing in cases involving drugs of abuse leads to heavy burden for law enforcement agencies, exacerbating demand for rapid screening technique. In this study, atmospheric pressure ionization technologies including direct analysis in real time (DART) ion source coupled to a time-of-flight mass spectrometer (DART-TOF-MS)as well asdopant-assisted positive photoionization ion mobility spectrometry (DAPP-IMS) without radioactivity were utilized together as the powerful analytical tool for the rapid screening and identification of 53 abused drugs.The limits of detection (LOD) were 0.05-2μg/mL when using DART-TOF-MS and 0.02-2μg when using DAPP-IMS which could satisfy the actual requirement in forensic science laboratory. The advantages of this method included fast response, high-throughput potential, high specificity, and minimal sample preparation. A screening library of reduced mobility (K 0 ), accurate mass of informative precursor ion ([M+H] + ) and fragment ions was established respectively by employing a bench-top DAPP-IMS and TOF-MS in-source collision induced dissociation (CID) mode. Then the standardized screening procedure was developed with criteria for the confirmation of positive result. A total of 50 seized drug samples provided by local forensic laboratory we reanalyzed to testify the utility of the method. This study suggests that a method combing DART-TOF-MS and DAPP-IMS is promising for the rapid screening and identification of abused drugs with minimal sample preparation and absence of chromatography. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Unusual Sclerosing Orbital Pseudotumor Infiltrating Orbits and Maxillofacial Regions

    Directory of Open Access Journals (Sweden)

    Huseyin Toprak

    2014-01-01

    Full Text Available Idiopathic orbital pseudotumor (IOP is a benign inflammatory condition of the orbit without identifiable local or systemic causes. Bilateral massive orbital involvement and extraorbital extension of the IOP is very rare. We present an unusual case of IOP with bilateral massive orbital infiltration extending into maxillofacial regions and discuss its distinctive magnetic resonance imaging (MRI features that help to exclude other entities during differential diagnoses.

  16. Molecular degrees of freedom: resonances and orbiting

    Energy Technology Data Exchange (ETDEWEB)

    Shapira, D.; Erb, K.A.

    1983-01-01

    Studies of orbiting and other gross features of heavy ion induced reactions show that molecular degrees of freedom play a significant role. The formation of a rotating dinuclear molecule appears as a general feature, and the radii derived for these dinuclear systems are larger than the radii of the conventional nucleus-nucleus potential. These large radii for the molecular bonding potential are similar to those derived from systematic studies performed recently on resonances in the /sup 12/C + /sup 12/C + /sup 16/O systems.

  17. Nuclear reactor power for an electrically powered orbital transfer vehicle

    International Nuclear Information System (INIS)

    Jaffe, L.; Beatty, R.; Bhandari, P.

    1987-01-01

    To help determine the systems requirements for a 300-kWe space nuclear reactor power system, a mission and spacecraft have been examined which utilize electric propulsion and this nuclear reactor power for multiple transfers of cargo between low Earth orbit (LEO) and geosynchronous Earth orbit (GEO). A propulsion system employing ion thrusters and xenon propellant was selected. Propellant and thrusters are replaced after each sortie to GEO. The mass of the Orbital Transfer Vehicle (OTV), empty and dry, is 11,000 kg; nominal propellant load is 5000 kg. The OTV operates between a circular orbit at 925 km altitude, 28.5 deg inclination, and GEO. Cargo is brought to the OTV by Shuttle and an Orbital Maneuvering Vehicle (OMV); the OTV then takes it to GEO. The OTV can also bring cargo back from GEO, for transfer by OMV to the Shuttle. OTV propellant is resupplied and the ion thrusters are replaced by the OMV before each trip to GEO. At the end of mission life, the OTV's electric propulsion is used to place it in a heliocentric orbit so that the reactor will not return to Earth. The nominal cargo capability to GEO is 6000 kg with a transit time of 120 days; 1350 kg can be transferred in 90 days, and 14,300 kg in 240 days. These capabilities can be considerably increased by using separate Shuttle launches to bring up propellant and cargo, or by changing to mercury propellant

  18. Status of Precise Orbit Determination for Jason-2 Using GPS

    Science.gov (United States)

    Melachroinos, S.; Lemoine, F. G.; Zelensky, N. P.; Rowlands, D. D.; Pavlis, D. E.

    2011-01-01

    The JASON-2 satellite, launched in June 2008, is the latest follow-on to the successful TOPEX/Poseidon (T/P) and JASON-I altimetry missions. JASON-2 is equipped with a TRSR Blackjack GPS dual-frequency receiver, a laser retroreflector array, and a DORIS receiver for precise orbit determination (POD). The most recent time series of orbits computed at NASA GSFC, based on SLR/DORIS data have been completed using both ITRF2005 and ITRF2008. These orbits have been shown to agree radially at 1 cm RMS for dynamic vs SLRlDORIS reduced-dynamic orbits and in comparison with orbits produced by other analysis centers (Lemoine et al., 2010; Zelensky et al., 2010; Cerri et al., 2010). We have recently upgraded the GEODYN software to implement model improvements for GPS processing. We describe the implementation of IGS standards to the Jason2 GEODYN GPS processing, and other dynamical and measurement model improvements. Our GPS-only JASON-2 orbit accuracy is assessed using a number of tests including analysis of independent SLR and altimeter crossover residuals, orbit overlap differences, and direct comparison to orbits generated at GSFC using SLR and DORIS tracking, and to orbits generated externally at other centers. Tests based on SLR and the altimeter crossover residuals provide the best performance indicator for independent validation of the NASAlGSFC GPS-only reduced dynamic orbits. For the ITRF2005 and ITRF2008 implementation of our GPS-only obits we are using the IGS05 and IGS08 standards. Reduced dynamic versus dynamic orbit differences are used to characterize the remaining force model error and TRF instability. We evaluate the GPS vs SLR & DORIS orbits produced using the GEODYN software and assess in particular their consistency radially and the stability of the altimeter satellite reference frame in the Z direction for both ITRF2005 and ITRF2008 as a proxy to assess the consistency of the reference frame for altimeter satellite POD.

  19. Low Earth Orbit Satellite’s Orbit Propagation and Determination

    Science.gov (United States)

    2014-01-01

    Institute of Technology Email: honien.shou@xuite.net Abstract This paper represents orbit propagation and determination of Low Eearth Orbit(LEO...Arichandran, S. H. Tan, T. Bretschneider, High – Presicion Onboard Orbit Determination for Small Satellites - the GPS-Based XNS on X-SAT. 6th Symposium on

  20. Study of ions - molecules reactions in the gas phase with collision reaction cell devices: Applications to the direct resolution of spectroscopic interferences in ICP-MS

    International Nuclear Information System (INIS)

    Favre, G.

    2008-12-01

    Inductively Coupled Plasma Mass Spectrometry emerged as the most widespread mass spectrometry technique in inorganic analytical chemistry for determining the concentration of a given isotope or an isotope ratio. The problem of spectroscopic interferences, inherent to this technique, finds a solution through the use of reaction cell devices. An in situ interference removal is feasible with the addition of a well selected gas in the cell. The understanding of the chemistry of ions-molecules interactions in the gas phase is however fundamental to optimize the efficiency of such devices. An accurate knowledge of experimental conditions in the reaction zone according to instrumental parameters appears crucial in order to interpret observed reactivities. This preliminary study is then used for the resolution of two nuclear field characteristic interferences. (author)

  1. Characterization of TiAlN thin film annealed under O2 by in situ time of flight direct recoil spectroscopy/mass spectroscopy of recoiled ions and ex situ x-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Tempez, A.; Bensaoula, A.; Schultz, A.

    2002-01-01

    The oxidation of an amorphous TiAlN coating has been studied by in situ direct recoil spectroscopy (DRS) and mass spectroscopy of recoiled ions (MSRI) and ex situ x-ray photoelectron spectroscopy (XPS). DRS and MSRI monitored the changes in surface composition as the sample was heated to 460 deg. C under an 18 O 2 pressure of 10 -6 Torr. Angular resolved XPS data were acquired for thickness-dependence information. The initial surface was partially oxidized from air exposure. Both DRS and XPS showed the Al-rich near surface and the presence of N in the subsurface. As shown by DRS and MSRI, oxidation at elevated temperatures yielded surface nitrogen loss and Ti enrichment. XPS confirmed the preferential formation of TiO 2 on the surface. This study also provides a comparison between the direct recoil (neutrals and ions) and the ionic recoil signals. In our conditions, the negative ionic fraction of all elements except H tracks their true surface content variations given by DRS. The results were compared with early work performed on identical samples. In this case the TiAlN film was oxidized with an O 2 pressure in the mTorr range and the surface changes are followed in situ by positive MSRI and XPS. This experiment also indicates that Al and N are buried under TiO 2 but from 600 deg. C

  2. Biomechanic Factors Associated With Orbital Floor Fractures.

    Science.gov (United States)

    Patel, Sagar; Andrecovich, Christopher; Silverman, Michael; Zhang, Liying; Shkoukani, Mahdii

    2017-07-01

    Orbital floor fractures are commonly seen in clinical practice, yet the etiology underlying the mechanism of fracture is not well understood. Current research focuses on the buckling theory and hydraulic theory, which implicate trauma to the orbital rim and the globe, respectively. To elucidate and define the biomechanical factors involved in an orbital floor fracture. A total of 10 orbits from 5 heads (3 male and 2 female) were used for this study. These came from fresh, unfixed human postmortem cadavers that were each selected so that the cause of death did not interfere with the integrity of orbital walls. Using a drop tower with an accelerometer, we measured impact force on the globe and rim of cadaver heads affixed with strain gauges. The mean impacts for rim and globe trauma were 3.9 J (95% CI, 3.4-4.3 J) and 3.9 J (95% CI, 3.5-4.3 J), respectively. Despite similar impact forces to the globe and rim, strain-gauge data displayed greater mean strain for globe impact (6563 μS) compared with rim impact (3530 μS); however, these data were not statistically significant (95% CI, 3598-8953 μS; P = .94). Our results suggest that trauma directly to the globe predisposes a patient to a more posterior fracture while trauma to the rim demonstrates an anterior predilection. Both the hydraulic and buckling mechanisms of fracture exist and demonstrate similar fracture thresholds. NA.

  3. Detection of lost alpha particle by concealed lost ion probe.

    Science.gov (United States)

    Okamoto, A; Isobe, M; Kitajima, S; Sasao, M

    2010-10-01

    Full orbit-following calculation is performed for the final orbit of the lost alpha particles, showing some orbits escaping from the last closed flux surface could be detected by a concealed lost ion probe (CLIP) installed under the shadow of the original first wall surface. While both passing and trapped orbits hit the same wall panel, detecting a trapped orbit by the CLIP is easier than detecting passing orbits. Whether the final orbit is detected or not is determined by the position of the reflection point. The CLIP successfully detects the trapped orbits, which are reflected before they hit to a first wall. Then the pitch angles of the orbits at the CLIP are close to and smaller than 90°. Optimization of the position of the CLIP in terms of broader detection window is investigated.

  4. Traumatic superior orbital fissure syndrome: a rare case report

    OpenAIRE

    Eskitascioglu, Teoman; Yontar, Yalcin; Aydin, Ahmet; Tucer, Bulent

    2017-01-01

    Superior orbital fissure syndrome is a severe clinical entity characterized by injuries of neurovascular structures passing through the superior orbital fissure. A 38-year-old male patient admitted to outpatient clinic with left upper eyelid ptosis, ecchymosis, mydriasis, hypoesthesia in upper eyelid and frontal region, blepharoptosis, restriction of ocular movements in all directions, loss of accommodation reflex and absence of direct pupillary reflex. Three-dimensional computed tomography s...

  5. Theory for spin and orbital orderings in high temperature phase in $YVO_3$

    OpenAIRE

    De Silva, Theja N.; Joshi, Anuvrat; Ma, Michael; Zhang, Fu Chun

    2003-01-01

    Motivated by the recent neutron diffraction experiment on $YVO_3$, we consider a microscopic model where each $V^{3+}$ ion is occupied by two 3d electrons of parallel spins with two fold degenerate orbital configurations. The mean field classical solutions of the spin-orbital superexchange model predicts an antiferro-orbital ordering at a higher temperature followed by a C-type antiferromagnetic spin ordering at a lower temperature. Our results are qualitatively consistent with the observed o...

  6. Orbital debris: a technical assessment

    National Research Council Canada - National Science Library

    National Research Council Staff; Commission on Engineering and Technical Systems; Division on Engineering and Physical Sciences; National Research Council; National Academy of Sciences

    ..., and other debris created as a byproduct of space operations. Orbital Debris examines the methods we can use to characterize orbital debris, estimates the magnitude of the debris population, and assesses the hazard that this population poses to spacecraft...

  7. GOC: General Orbit Code

    International Nuclear Information System (INIS)

    Maddox, L.B.; McNeilly, G.S.

    1979-08-01

    GOC (General Orbit Code) is a versatile program which will perform a variety of calculations relevant to isochronous cyclotron design studies. In addition to the usual calculations of interest (e.g., equilibrium and accelerated orbits, focusing frequencies, field isochronization, etc.), GOC has a number of options to calculate injections with a charge change. GOC provides both printed and plotted output, and will follow groups of particles to allow determination of finite-beam properties. An interactive PDP-10 program called GIP, which prepares input data for GOC, is available. GIP is a very easy and convenient way to prepare complicated input data for GOC. Enclosed with this report are several microfiche containing source listings of GOC and other related routines and the printed output from a multiple-option GOC run

  8. Topics in orbit equivalence

    CERN Document Server

    Kechris, Alexander S

    2004-01-01

    This volume provides a self-contained introduction to some topics in orbit equivalence theory, a branch of ergodic theory. The first two chapters focus on hyperfiniteness and amenability. Included here are proofs of Dye's theorem that probability measure-preserving, ergodic actions of the integers are orbit equivalent and of the theorem of Connes-Feldman-Weiss identifying amenability and hyperfiniteness for non-singular equivalence relations. The presentation here is often influenced by descriptive set theory, and Borel and generic analogs of various results are discussed. The final chapter is a detailed account of Gaboriau's recent results on the theory of costs for equivalence relations and groups and its applications to proving rigidity theorems for actions of free groups.

  9. Autonomous Orbit Navigator Development, Using GPS, Applied to Autonomous Orbit Control

    Science.gov (United States)

    Galski, Roberto Luiz

    2002-01-01

    The appearance of modem global positioning systems motivated the study and development of precise and robust systems for autonomous orbit determination of artificial satellites. These systems maintain, independently from human intervention from the ground, a precise knowledge of the satellite orbital state, through the processing of the information, autonomously generated on-board, by a receiver of the positioning system used. One of the major motivations for the research and development of autonomous navigators, is the availability of real time information about the position and velocity of the satellite, required, for instance, in earth observation missions, for interpretation and analysis of the generated images. The appearance of global positioning systems and the consequent development of autonomous navigators, by making available onboard space vehicles, updated orbit estimations, with good accuracy level, made feasible the research and development of orbit autonomous control procedures. It allowed the orbital maneuvers execution process to be performed in a way totally independent from ground human intervention. Whereas the satellite attitude control reached a high level of autonomy, due to the fact that the attitude measurements are, in general, naturally generated on-board the spacecraft, the orbit control is still now almost totally planned and executed from ground commanded actions. The proposed work consists of the study, development, simulation and analysis of a simplified navigator coupled to an autonomous orbit control system, applied to the China-Brazil Earth Resources Satellites (CBERS). At first, an autonomous orbit determination procedure is developed and analyzed. Its objective is to improve the coarse geometric solution provided by Global Positioning System (GPS) receivers. This will be done by directly using this solution as input (observation) for a real time Kalman filtering process. The orbital state vector will be extended in order to

  10. Small Mercury Relativity Orbiter

    Science.gov (United States)

    Bender, Peter L.; Vincent, Mark A.

    1989-01-01

    The accuracy of solar system tests of gravitational theory could be very much improved by range and Doppler measurements to a Small Mercury Relativity Orbiter. A nearly circular orbit at roughly 2400 km altitude is assumed in order to minimize problems with orbit determination and thermal radiation from the surface. The spacecraft is spin-stabilized and has a 30 cm diameter de-spun antenna. With K-band and X-band ranging systems using a 50 MHz offset sidetone at K-band, a range accuracy of 3 cm appears to be realistically achievable. The estimated spacecraft mass is 50 kg. A consider-covariance analysis was performed to determine how well the Earth-Mercury distance as a function of time could be determined with such a Relativity Orbiter. The minimum data set is assumed to be 40 independent 8-hour arcs of tracking data at selected times during a two year period. The gravity field of Mercury up through degree and order 10 is solved for, along with the initial conditions for each arc and the Earth-Mercury distance at the center of each arc. The considered parameters include the gravity field parameters of degree 11 and 12 plus the tracking station coordinates, the tropospheric delay, and two parameters in a crude radiation pressure model. The conclusion is that the Earth-Mercury distance can be determined to 6 cm accuracy or better. From a modified worst-case analysis, this would lead to roughly 2 orders of magnitude improvement in the knowledge of the precession of perihelion, the relativistic time delay, and the possible change in the gravitational constant with time.

  11. Plotting Orbital Trajectories For Maneuvers

    Science.gov (United States)

    Brody, Adam R.

    1991-01-01

    Interactive Orbital Trajectory Planning Tool (EIVAN) computer program is forward-looking interactive orbit-trajectory-plotting software tool for use with proximity operations (operations occurring within 1-km sphere of space station) and other maneuvers. Developed to plot resulting trajectories, to provide better comprehension of effects of orbital mechanics, and to help user develop heuristics for planning missions on orbit. Program runs with Microsoft's Excel for execution on MacIntosh computer running MacIntosh OS.

  12. Preseptal and orbital cellulitis

    Directory of Open Access Journals (Sweden)

    Emine Akçay

    2014-09-01

    Full Text Available Preseptal cellulitis (PC is defined as an inflammation of the eyelid and surrounding skin, whereas orbital cellulitis (OC is an inflammation of the posterior septum of the eyelid affecting the orbit and its contents. Periorbital tissues may become infected as a result of trauma (including insect bites or primary bacteremia. Orbital cellulitis generally occurs as a complication of sinusitis. The most commonly isolated organisms are Staphylococcus aureus, Streptococcus pneumoniae, S. epidermidis, Haempphilus influenzae, Moraxella catarrhalis and S. pyogenes. The method for the diagnosis of OS and PS is computed tomography. Using effective antibiotics is a mainstay for the treatment of PC and OC. There is an agreement that surgical drainage should be performed in cases of complete ophthalmoplegia or significant visual impairment or large abscesses formation. This infections are also at a greater risk of acute visual loss, cavernous sinus thrombosis, meningitis, cerebritis, endophthalmitis, and brain abscess in children. Early diagnosis and appropriate treatment are crucial to control the infection. Diagnosis, treatment, management and complications of PC and OC are summarized in this manuscript. J MicrobiolInfect Dis 2014; 4(3: 123-127

  13. Non-Liouvillean ion injection via resonantly enhanced two-photon ionization

    Directory of Open Access Journals (Sweden)

    B. A. Knyazev

    2004-03-01

    Full Text Available The charge-exchange method is now one of the main techniques for ion injection into accelerators and storage rings. The disadvantages of conventional methods, based on the atom or ion stripping in a material target, are emittance growth, energy straggling, and production of ions in many charge states. Recently suggested stripping methods based on direct photoionization require employment of hard-UV lasers, which still do not exist and must obviously be very bulky and expensive. An alternative method, suggested for injection of proton beams, employs excitation of the atom to 3p intermediate state with subsequent Lorentz ionization in a magnetic field gradient. This technique applies rigid requirements to laser characteristic and is not free of growing of the beam divergence. In this paper a variant of the stripping technique based on the resonantly enhanced two-photon ionization (RETPI is considered. The technique allows ionization of singly charged ions of the elements from helium to bismuth. A variant of the technique can be used for proton injection. RETPI can be applied for both ion injection and stacking, as well as for diagnostics of ion beam characteristics on the orbit. Stripping efficiency can be about 100% for the singly charged ions having the singlet ground state and decreases for the other ions. Special methods for “cleaning” unwanted atomic states in such ions, that can provide high stripping efficiency, are discussed. Excimer lasers with very moderate parameters can be employed for implementation of this technique for almost all elements. Numerical examples show that for most of the singly charged ions and for hydrogen atom necessary laser-beam energy density is merely 0.5–8  J/cm^{2} for a 1 m interaction region, and is 10 times higher for several light ions.

  14. Molecular ion photofragment spectroscopy

    International Nuclear Information System (INIS)

    Bustamente, S.W.

    1983-11-01

    A new molecular ion photofragment spectrometer is described which features a supersonic molecular beam ion source and a radio frequency octapole ion trap interaction region. This unique combination allows several techniques to be applied to the problem of detecting a photon absorption event of a molecular ion. In particular, it may be possible to obtain low resolution survey spectra of exotic molecular ions by using a direct vibrational predissociation process, or by using other more indirect detection methods. The use of the spectrometer is demonstrated by measuring the lifetime of the O 2 + ( 4 π/sub u/) metastable state which is found to consist of two main components: the 4 π/sub 5/2/ and 4 π/sub -1/2/ spin components having a long lifetime (approx. 129 ms) and the 4 π/sub 3/2/ and 4 π/sub 1/2/ spin components having a short lifetime (approx. 6 ms)

  15. Orbital Cellulitis of Odontogenic Origin.

    Science.gov (United States)

    Yan, William; Chakrabarti, Rahul; Choong, Jessica; Hardy, Thomas

    2015-01-01

    Odontogenic orbital cellulitis, although uncommon, has the potential to cause severe vision loss if unsuspected and untreated. Compared to non-odontogenic bacteriology, odontogenic orbital abscesses typically feature a heavy mixed growth with anaerobic organisms. We review the literature and discuss the case of a 26-year-old male who presented with anaerobic orbital cellulitis for treatment.

  16. Orbiter OMS and RCS technology

    Science.gov (United States)

    Boudreaux, R. A.

    1982-01-01

    Orbiter Orbital Maneuver Subsystem (OMS) and Reaction Control Subsystem (RCS) tankage has proved to be highly successful in shuttle flights on-orbit propellant transfer tests were done. Tank qualification tests along with flight demonstrations were carried out future uses of storable propellants are cited.

  17. Prediction of acrylamide formation in biscuits based on fingerprint data generated by ambient ionization mass spectrometry employing direct analysis in real time (DART) ion source

    NARCIS (Netherlands)

    Vaclavik, Lukas; Capuano, Edoardo; Gökmen, Vural; Hajslova, Jana

    2015-01-01

    The objective of this study is the evaluation of the potential of high-throughput direct analysis in real time-high resolution mass spectrometry (DART-HRMS) fingerprinting and multivariate regression analysis in prediction of the extent of acrylamide formation in biscuit samples prepared by

  18. Retinoblastoma associated orbital cellulitis

    Science.gov (United States)

    Mullaney, P.; Karcioglu, Z.; Huaman, A.; Al-Mesfer, S.

    1998-01-01

    AIM—Preseptal and orbital cellulitis are rare presenting features of intraocular retinoblastoma. The objectives of this study were to determine the frequency of retinoblastoma associated cellulitis, as well as to review its clinical and histopathological features.
METHODS—The medical records of 292 retinoblastoma patients in the King Khaled Eye Specialist Hospital in Riyadh, Saudi Arabia were reviewed. Those indicating a history of, or presenting with, cellulitis were retrieved and their clinical, radiological, and histopathological variables were assessed. Patients with definite extraocular tumour extension on clinical or radiological examination were excluded.
RESULTS—14 patients were found to have retinoblastoma associated cellulitis (4.8%); nine had bilateral and five had unilateral retinoblastoma. Conjunctival and blood cultures were performed in 10 cases and were negative. 10 children were treated with intravenous steroids, often in conjunction with antibiotics, resulting in a prompt decrease in inflammation. Three other children were treated with antibiotics alone and one received no treatment. Computed tomographic scanning depicted large intraocular tumours occupying between 80% and 100% of the globe in each case. In eight patients, periocular inflammation was radiologically interpreted as possible extraocular extension. In one patient serial computed tomographic scanning showed a reduction in intraocular calcification over time which occurred in the presence of cellulitis. 12 patients underwent enucleation and histopathological examination revealed large necrotic, poorly differentiated tumours associated with uveal involvement and early optic nerve invasion. Focal perilimbal destruction was seen in one patient, and in another peripapillary extrascleral extension was present. 12 patients are alive with a mean follow up of 56.4 months.
CONCLUSIONS—Radiological evaluation of scleral integrity may be hindered by periocular inflammatory

  19. Orbital Cellulitis Following Orbital Blow-out Fracture.

    Science.gov (United States)

    Byeon, Je Yeon; Choi, Hwan Jun

    2017-10-01

    Orbital cellulitis and abscess have been described in the literature as complication that usually occur secondary to infection in the maxillary, ethmoidal, and frontal sinuses. If left untreated, it can lead to blindness, cavernous sinus thrombosis, meningitis, or cerebral abscess. Orbital fractures are a common sequela of blunt orbital trauma, but are only rarely associated with orbital cellulitis. So, the authors present rare orbital cellulitis after orbital blow-out fracture. A 55-year-old Asian complains of severe orbital swelling and pain on the left side. These symptoms had started 2 days earlier and worsened within the 24 hours before hospital admission resulting in visual disturbances such as diplopia and photophobia. Contrast-enhanced computed tomography scan showed considerable soft tissue swelling and abscess formation on the left side. Patient was subjected to surgical drainage under general anesthesia in the operation room. In this case, the postoperative period was uneventful and the rapid improvement of symptoms was remarkable. In conclusion, the abscess of the orbit is a surgical emergency in patients whose impairment of vision or ocular symptoms cannot be controlled with medical therapy using antibiotics. In our case, orbital cellulitis can occur after blunt orbital trauma without predisposing sinusitis. Early and prompt diagnosis and surgical drainage before severe loss of visual acuity rescue or recover the vision in case of orbital cellulitis.

  20. Plasma density fluctuations observed during Space Shuttle Orbiter water releases

    Science.gov (United States)

    Pickett, J. S.; D'Angelo, N.; Kurth, W. S.

    1989-01-01

    Observations by the Langmuir probe on the Plasma Diagnostics Package flown as part of the Spacelab 2 mission in the summer of 1985 show a strong increase in the level of turbulence near the Shuttle Orbiter during operations in which liquid water is released. The spectrum of the plasma density fluctuations peaks at the lowest frequencies measured (a few Hz) and extends up to a few kHz, near the lower hybrid frequency. Two potential mechanisms for generating the plasma turbulence are suggested which are both based on the production of water ions as a result of charge exchange with the ambient oxygen ions in the ionosphere. The first mechanism proposed is the ion-plasma instability which arises from the drift of the contaminant with respect to the ambient oxygen ions. The other mechanism proposed is the Ott-Farley instability, which is a result of the ring distribution formed by the 'pick-up' water ions.

  1. Precise orbits of the Lunar Reconnaissance Orbiter from radiometric tracking data

    Science.gov (United States)

    Löcher, Anno; Kusche, Jürgen

    2018-02-01

    Since 2009, the Lunar Reconnaissance Orbiter (LRO) acquires images and altimetric profiles of the lunar surface. Assembling these data to maps and terrain models requires the precise knowledge of the spacecraft trajectory. In this contribution, we present 5 years of LRO orbits from radiometric data processed with a software tailored to this mission. The presented orbits are the first independent validation of the LRO science orbits from NASA and are available for public use. A key feature of our processing is the elaborate treatment of model and observation errors by empirical parameters and an adaptive data weighting by variance component estimation. The quality of the resulting orbits is assessed by analyzing overlapping arcs. For our solution based on arcs of 2.5 days, such analysis yields a mean error of 2.81 m in total position and 0.11 m in radial direction. It is shown that this result greatly benefits from the adaptive data weighting, reducing the error by 2.54 and 0.13 m, respectively. Unfortunately, the precision achieved varies strongly, dependent on the view onto the orbital ellipse which changes with the lunar cycle. To mitigate this dependency, the arc length was extended in steps up to 10.5 days, leading in the best case to a further improvement of 0.80 m.

  2. Carbon quantum dots directly generated from electrochemical oxidation of graphite electrodes in alkaline alcohols and the applications for specific ferric ion detection and cell imaging.

    Science.gov (United States)

    Liu, Mengli; Xu, Yuanhong; Niu, Fushuang; Gooding, J Justin; Liu, Jingquan

    2016-04-25

    Carbon quantum dots (CQDs) are attracting tremendous interest owing to their low toxicity, water dispersibility, biocompatibility, optical properties and wide applicability. Herein, CQDs with an average diameter of (4.0 ± 0.2) nm and high crystallinity were produced simply from the electrochemical oxidation of a graphite electrode in alkaline alcohols. The as-formed CQDs dispersion was colourless but the dispersion gradually changed to bright yellow when stored in ambient conditions. Based on UV-Vis absorption, fluorescence spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and high-resolution transmission electron microscopy (HRTEM), this colour change appeared to be due to oxygenation of surface species over time. Furthermore, the CQDs were used in specific and sensitive detection of ferric ion (Fe(3+)) with broad linear ranges of 10-200 μM with a low limit of detection of 1.8 μM (S/N = 3). The application of the CQDs for Fe(3+) detection in tap water was demonstrated and the possible mechanism was also discussed. Finally, based on their good characteristics of low cytotoxicity and excellent biocompatibility, the CQDs were successfully applied to cell imaging.

  3. Plasma source ion implantation

    International Nuclear Information System (INIS)

    Conrad, J.R.; Forest, C.

    1986-01-01

    The authors' technique allows the ion implantation to be performed directly within the ion source at higher currents without ion beam extraction and transport. The potential benefits include greatly increased production rates (factors of 10-1000) and the ability to implant non-planar targets without rastering or shadowing. The technique eliminates the ion extractor grid set, beam raster equipment, drift space and target manipulator equipment. The target to be implanted is placed directly within the plasma source and is biased to a large negative potential so that plasma ions gain energy as they accelerate through the potential drop across the sheath that forms at the plasma boundary. Because the sheath surrounds the target on all sides, all surfaces of the target are implanted without the necessity to raster the beam or to rotate the target. The authors have succeeded in implanting nitrogen ions in a silicon target to the depths and concentrations required for surface treatment of materials like stainless steel and titanium alloys. They have performed ESCA measurements of the penetration depth profile of a silicon target that was biased to 30 kV in a nitrogen discharge plasma. Nitrogen ions were implanted to a depth of 700A at a peak concentration of 30% atomic. The measured profile is quite similar to a previously obtained profile in titanium targets with conventional techniques

  4. Molecular orbital calculations using chemical graph theory

    CERN Document Server

    Dias, Jerry Ray

    1993-01-01

    Professor John D. Roberts published a highly readable book on Molecular Orbital Calculations directed toward chemists in 1962. That timely book is the model for this book. The audience this book is directed toward are senior undergraduate and beginning graduate students as well as practicing bench chemists who have a desire to develop conceptual tools for understanding chemical phenomena. Although, ab initio and more advanced semi-empirical MO methods are regarded as being more reliable than HMO in an absolute sense, there is good evidence that HMO provides reliable relative answers particularly when comparing related molecular species. Thus, HMO can be used to rationalize electronic structure in 1t-systems, aromaticity, and the shape use HMO to gain insight of simple molecular orbitals. Experimentalists still into subtle electronic interactions for interpretation of UV and photoelectron spectra. Herein, it will be shown that one can use graph theory to streamline their HMO computational efforts and to arrive...

  5. Orbit Propagation and Determination of Low Earth Orbit Satellites

    Directory of Open Access Journals (Sweden)

    Ho-Nien Shou

    2014-01-01

    Full Text Available This paper represents orbit propagation and determination of low Earth orbit (LEO satellites. Satellite global positioning system (GPS configured receiver provides position and velocity measures by navigating filter to get the coordinates of the orbit propagation (OP. The main contradictions in real-time orbit which is determined by the problem are orbit positioning accuracy and the amount of calculating two indicators. This paper is dedicated to solving the problem of tradeoffs. To plan to use a nonlinear filtering method for immediate orbit tasks requires more precise satellite orbit state parameters in a short time. Although the traditional extended Kalman filter (EKF method is widely used, its linear approximation of the drawbacks in dealing with nonlinear problems was especially evident, without compromising Kalman filter (unscented Kalman Filter, UKF. As a new nonlinear estimation method, it is measured at the estimated measurements on more and more applications. This paper will be the first study on UKF microsatellites in LEO orbit in real time, trying to explore the real-time precision orbit determination techniques. Through the preliminary simulation results, they show that, based on orbit mission requirements and conditions using UKF, they can satisfy the positioning accuracy and compute two indicators.

  6. Nontraumatic subperiosteal orbital hematoma associated with ethmoid sinusitis: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Soo; Han, Jong Kyu; Baek, Byoung Joon; Oh, Mee Hye; Jou, Sung Shick; Kim, Hyung Hwan; Bae, Won Kyung; Kim, Il Young [Soonchunhyang University, Cheonan Hospital, Cheonan (Korea, Republic of)

    2007-08-15

    Subperiosteal hematoma of the orbit is a rare disease and most of the cases occur in young adult males as a result of direct facial or orbital trauma. In the absence of direct facial or orbital trauma, nontranmatic subperiosteal orbital hematoma has rarely been reported in association with a sudden elevation of cranial venous pressure or venous congestion, systemic diseases associated with a bleeding diathesis and paranasal sinusitis. We report here on a rare case of subperiosteal orbital hemaboma associated with ethmoid sinusitis, as was seen on CT imaging.

  7. Rapid screening of 35 new psychoactive substances by ion mobility spectrometry (IMS) and direct analysis in real time (DART) coupled to quadrupole time-of-flight mass spectrometry (QTOF-MS).

    Science.gov (United States)

    Gwak, Seongshin; Almirall, Jose R

    2015-10-01

    The recent propagation of new psychoactive substances (NPS) has led to the development of new techniques for the rapid characterization of controlled substances in this category. A commercial bench-top ion mobility spectrometer (IMS) with a (63) Ni ionization source and a direct analysis in real time (DART) coupled to quadrupole time-of-flight (QTOF) were used for the rapid characterization of 35 NPS. The advantages of these techniques are fast response, ease of operation, and minimal sample preparation. The characteristic reduced mobilities of each substance are reported as are the mass spectra of the 35 compounds. The acquired product ion scan mass spectra were also compared to a library database constructed by QTOF with a electrospray ionization (ESI) source and showed a consistent relative abundance for each peak over time. A total of four seized drug samples provided by the local forensic laboratory were analyzed in order to demonstrate the utility of this approach. The results of this study suggest that both IMS and DART-QTOF are promising alternatives for the rapid screening and characterization of these new psychoactive substances. Copyright © 2015 John Wiley & Sons, Ltd.

  8. Lithium ion storage between graphenes

    Directory of Open Access Journals (Sweden)

    Chan Yue

    2011-01-01

    Full Text Available Abstract In this article, we investigate the storage of lithium ions between two parallel graphene sheets using the continuous approximation and the 6-12 Lennard-Jones potential. The continuous approximation assumes that the carbon atoms can be replaced by a uniform distribution across the surface of the graphene sheets so that the total interaction potential can be approximated by performing surface integrations. The number of ion layers determines the major storage characteristics of the battery, and our results show three distinct ionic configurations, namely single, double, and triple ion forming layers between graphenes. The number densities of lithium ions between the two graphenes are estimated from existing semi-empirical molecular orbital calculations, and the graphene sheets giving rise to the triple ion layers admit the largest storage capacity at all temperatures, followed by a marginal decrease of storage capacity for the case of double ion layers. These two configurations exceed the maximum theoretical storage capacity of graphite. Further, on taking into account the charge-discharge property, the double ion layers are the most preferable choice for enhanced lithium storage. Although the single ion layer provides the least charge storage, it turns out to be the most stable configuration at all temperatures. One application of the present study is for the design of future high energy density alkali batteries using graphene sheets as anodes for which an analytical formulation might greatly facilitate rapid computational results.

  9. Ion Colliders

    CERN Document Server

    Fischer, W

    2014-01-01

    High-energy ion colliders are large research tools in nuclear physics to study the Quark-Gluon-Plasma (QGP). The range of collision energy and high luminosity are important design and operational considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species. Ion species range from protons, including polarized protons in RHIC, to heavy nuclei like gold, lead and uranium. Asymmetric collision combinations (e.g. protons against heavy ions) are also essential. For the creation, acceleration, and storage of bright intense ion beams, limits are set by space charge, charge change, and intrabeam scattering effects, as well as beam losses due to a variety of other phenomena. Currently, there are two operating ion colliders, the Relativistic Heavy Ion Collider (RHIC) at BNL, and the Large Hadron Collider (LHC) at CERN.

  10. Los Alamos energetic particle sensor systems at geostationary orbit

    International Nuclear Information System (INIS)

    Baker, D.N.; Aiello, W.; Asbridge, J.R.; Belian, R.D.; Higbie, P.R.; Klebesadel, R.W.; Laros, J.G.; Tech, E.R.

    1985-01-01

    The Los Alamos National Laboratory has provided energetic particle sensors for a variety of spacecraft at the geostationary orbit (36,000 km altitude). The sensor system called the Charged Particle Analyzer (CPA) consists of four separate subsystems. The LoE and HiE subsystems measure electrons in the energy ranges 30 to 300 keV and 200 to 2000 keV, respectively. The LoP and HiP subsystems measure ions in the ranges 100 to 600 keV and 0.40 to 150 MeV, respectively. A separate sensor system called the spectrometer for energetic electrons (SEE) measures very high-energy electrons (2 to 15 MeV) using advanced scintillator design. In this paper we describe the relationship of operational anomalies and spacecraft upsets to the directly measured energetic particle environments at 6.6 R/sub E/. We also compare and contrast the CPA and SEE instrument design characteristics with the next generation of Los Alamos instruments to be flown at geostationary altitudes

  11. Precise Orbit Determination of GPS Satellites Using Phase Observables

    Directory of Open Access Journals (Sweden)

    Myung-Kook Jee

    1997-12-01

    Full Text Available The accuracy of user position by GPS is heavily dependent upon the accuracy of satellite position which is usually transmitted to GPS users in radio signals. The real-time satellite position information directly obtained from broadcast ephimerides has the accuracy of 3 x 10 meters which is very unsatisfactory to measure 100km baseline to the accuracy of less than a few mili-meters. There are globally at present seven orbit analysis centers capable of generating precise GPS ephimerides and their orbit quality is of the order of about 10cm. Therefore, precise orbit model and phase processing technique were reviewed and consequently precise GPS ephimerides were produced after processing the phase observables of 28 global GPS stations for 1 day. Initial 6 orbit parameters and 2 solar radiation coefficients were estimated using batch least square algorithm and the final results were compared with the orbit of IGS, the International GPS Service for Geodynamics.

  12. Stationary orbits of comets perturbed by Galactic tides

    Science.gov (United States)

    Breiter, S.; Fouchard, M.; Ratajczak, R.

    2008-01-01

    Using the first-order normalized equations describing the heliocentric cometary motion perturbed by the Galactic tides, we identify `stationary solutions' with constant values of the eccentricity, inclination, argument of perihelion and longitude of the ascending node in the reference frame rotating with the Galaxy. The families found involve circular orbits, orbits in the Galactic equatorial plane, rectilinear orbits normal to the equatorial plane, elliptic orbits symmetric with respect to the direction to the Galactic Centre or to its perpendicular, and asymmetrically oriented elliptic orbits. Linear stability of the stationary solution is studied analytically and confirmed by numerical experiments. Most, but not all, of the unstable solutions prove chaotic with the Lyapunov times at least 100Myr.

  13. A Typical Presentation of Orbital Pseudotumor Mimicking Orbital Cellulitis

    Directory of Open Access Journals (Sweden)

    J. Ayatollahi

    2013-10-01

    Full Text Available Introduction: Orbital pseudotumor, also known as idiopathic orbital inflammatory syndrome (IOIS, is a benign, non- infective inflammatory condition of the orbit without identifiable local or systemic causes. The disease may mimics a variety of pathologic conditions. We pre-sent a case of pseudotumor observed in a patient admitted under the name of orbital celluli-ties. Case Report: A 26-year-old woman reffered to our hospital with the history of left ocular pain and headache 2 days before her visit.. Ophthalmological examination of the patient was normal except for the redness and lid edema, mild chemosis and conjunctival injection. Gen-eral assessment was normal but a low grade fever was observed. She was hospitalized as an orbital cellulitis patient. She was treated with intravenous antibiotics. On the third day , sud-denly diplopia, proptosis in her left eye and ocular pain in her right side appeared. MRI re-vealed bilateral enlargement of extraocular muscles. Diagnosis of orbital pseudotumor was made and the patient was treated with oral steroid.She responded promptly to the treatment. Antibiotics were discontinued and steroid was tapered in one month period under close fol-low up. Conclusion: The clinical features of orbital pseudotumor vary widely . Orbital pseudotumor and orbital cellulitis can occasionally demonstrate overlapping features.. Despite complete physical examination and appropriate imaging, sometimes correct diagnosis of the disease would be difficult (Sci J Hamadan Univ Med Sci 2013; 20 (3:256-259

  14. Magnetically dressed one-electron molecular orbitals

    International Nuclear Information System (INIS)

    Wille, U.

    1988-01-01

    A general method for solving the stationary one-electron, two-center Coulomb problem with a superimposed (uniform) strong magnetic field is described and applied. For arbitrary orientation of the field with respect to the line connecting the centers, the pertinent Schroedinger equation is solved by evaluating analytically the Hamiltonian matrix in a basis of (nonorthogonal) Hylleraas functions and solving numerically the generalized eigenvalue problem for this matrix. A detailed study of the properties of ''magnetically dressed'' (diatomic) one-electron molecular orbitals is performed by calculating energies and wave functions for the H 2 + and (H-He)/sup 2+/ systems for field strengths up to about 10 8 T. Molecular-orbital correlation diagrams are presented and discussed, in which dressed-orbital energies are displayed as a function of internuclear distance R at fixed angle θ between field direction and internuclear axis, and as a function of θ at fixed R. Equilibrium internuclear distances and total binding energies are calculated as functions of field strength for the magnetically dressed H 2 + system in its lowest gerade and ungerade states at θ = 0 and θ = 90 0 . The influence of the magnetic field on molecular binding properties as well as on the separation behavior of molecular orbitals at large internuclear distances is illustrated by means of wave-function plots. Whenever possible, our results are compared to those of previous investigations. The convergence properties of our method are discussed

  15. Theoretical study of valence orbital response to guanine tautomerization in coordinate and momentum spaces

    International Nuclear Information System (INIS)

    Yang, Zejin; Duffy, Patrick; Zhu, Quan; Wang, Feng; Takahashi, Masahiko

    2015-01-01

    The binding energy spectra and electron momentum spectra of eight stable guanine tautomers are calculated in the complete valence space. The present results show that the canonical keto (C=O) guanine N(9)H tautomer (GU1) possesses the largest dipole moment, molecular electronic spatial extent, molecular hardness value, and the minimum first vertical ionization potential (VIP). Valence orbital profile investigations find that several orbitals remain almost unchanged during tautomerization, such as frontier highest occupied molecular orbital 39a and 18a. Several orbitals with interchanged order and inverse direction in charge spatial orientations are also detected. Outer valence orbitals (with smaller VIPs) show more complex orbital shapes in the momentum space than those of inner ones (larger VIPs) due mainly to the relatively strong inter-orbital interaction and delocalized electronic distributions. Proton rotation along C–O(H) and C–N(H) axes within hexagonal ring causes smaller influence to orbital profiles than those of proton migration within pentagonal and/or hexagonal rings. Orbital variation trends between enol (GU3–GU5) and keto (GU1, GU2, GU6–GU8) tautomers are observed, including the signature orbitals of enol form, the variation tendency of total orbital intensity, and the variation order of the maximum orbital intensity. In the outer valence momentum space (outside 26a), orbital composed by p z electrons show single peak with a gradual increasing peak site from 0.5 a.u. of inner valence orbital to 1.0 a.u. of outer valence orbital, whereas orbitals composed by p x,y electrons form double peaks with respective sites at about 0.5 and 1.5 a.u., only three p x,y -orbitals present single peaks (33a,34a,36a). The general variation trends in the complete valence space for all the valence orbitals on their intensities, peak sites, and orbital components are concluded. (paper)

  16. Zero-field splitting of 4T2 term for 3d3 ions in tetragonal symmetry

    Indian Academy of Sciences (India)

    Abstract. By taking into account slight interactions, i.e. spin-spin, spin-other-orbit and orbit-orbit interactions, in addition to spin-orbit interaction, the zero-field splitting of 4T2 state for 3d3 ions at tetragonal symmetry has been studied. The convergence of the approximation perturbation formula of 4T2 state for 3d3 ions at ...

  17. Lunar Reconnaissance Orbiter

    Science.gov (United States)

    Morgan, T.; Chin, G.

    2007-08-01

    NASA's Lunar Reconnaissance Orbiter (LRO) plans to launch in October 2008 with a companion secondary impactor mission, LCROSS, as the inaugural missions for the Exploration System Mission Directorate. LRO is a pathfinder whose objective is to obtain the needed information to prepare for eventual human return to the Moon. LRO will undertake at least one baseline year of operation with additional extended mission phase sponsored by NASA's Science Mission Directorate. LRO will employ six individual instruments to produce accurate maps and high-resolution images of future landing sites, to assess potential lunar resources, and to characterize the radiation environment. LRO will also test the feasibility of one advanced technology demonstration package. The LRO payload includes: Lunar Orbiter Laser Altimeter (LOLA) which will determine the global topography of the lunar surface at high resolution, measure landing site slopes, surface roughness, and search for possible polar surface ice in shadowed regions; Lunar Reconnaissance Orbiter Camera (LROC) which will acquire targeted narrow angle images of the lunar surface capable of resolving meter-scale features to support landing site selection, as well as wide-angle images to characterize polar illumination conditions and to identify potential resources; Lunar Exploration Neutron Detector (LEND) which will map the flux of neutrons from the lunar surface to search for evidence of water ice, and will provide space radiation environment measurements that may be useful for future human exploration; Diviner Lunar Radiometer Experiment (DLRE) which will chart the temperature of the entire lunar surface at approximately 300 meter horizontal resolution to identify cold-traps and potential ice deposits; Lyman-Alpha Mapping Project (LAMP) which will map the entire lunar surface in the far ultraviolet. LAMP will search for surface ice and frost in the polar regions and provide images of permanently shadowed regions illuminated only

  18. Orbit Determination of Spacecraft in Earth-Moon L1 and L2 Libration Point Orbits

    Science.gov (United States)

    Woodard, Mark; Cosgrove, Daniel; Morinelli, Patrick; Marchese, Jeff; Owens, Brandon; Folta, David

    2011-01-01

    measurements that would be needed to meet the required orbit determination accuracies. Analysts used the Orbit Determination Error Analysis System (ODEAS) to perform covariance analyses using various tracking data schedules. From this analysis, it was determined that 3.5 hours of DSN TRK-2-34 range and Doppler tracking data every other day would suffice to meet the predictive orbit knowledge accuracies in the Lissajous region. The results of this analysis are presented. Both GTDS and ODTK have high-fidelity environmental orbit force models that allow for very accurate orbit estimation in the lunar Lissajous regime. These models include solar radiation pressure, Earth and Moon gravity models, third body gravitational effects from the Sun, and to a lesser extent third body gravitational effects from Jupiter, Venus, Saturn, and Mars. Increased position and velocity uncertainties following each maneuver, due to small execution performance errors, requires that several days of post-maneuver tracking data be processed to converge on an accurate post-maneuver orbit solution. The effects of maneuvers on orbit determination accuracy will be presented, including a comparison of the batch least squares technique to the extended Kalman filter/smoother technique. We will present the maneuver calibration results derived from processing post-maneuver tracking data. A dominant error in the orbit estimation process is the uncertainty in solar radiation pressure and the resultant force on the spacecraft. An estimation of this value can include many related factors, such as the uncertainty in spacecraft reflectivity and surface area which is a function of spacecraft orientation (spin-axis attitude), uncertainty in spacecraft wet mass, and potential seasonal variability due to the changing direction of the Sun line relative to the Earth-Moon Lissajous reference frame. In addition, each spacecraft occasionally enters into Earth or Moon penumbra or umbra and these shadow crossings reduche solar

  19. Time-domain inspiral templates for spinning compact binaries in quasi-circular orbits described by their orbital angular momenta

    International Nuclear Information System (INIS)

    Gupta, A; Gopakumar, A

    2014-01-01

    We present a prescription to compute the time-domain gravitational wave (GW) polarization states associated with spinning compact binaries inspiraling along quasi-circular orbits. We invoke the orbital angular momentum L rather than its Newtonian counterpart L N to describe the binary orbits while the two spin vectors are freely specified in an inertial frame associated with the initial direction of the total angular momentum. We show that the use of L to describe the orbits leads to additional 1.5PN order amplitude contributions to the two GW polarization states compared to the L N -based approach and discuss few implications of our approach. Furthermore, we provide a plausible prescription for GW phasing based on certain theoretical considerations and which may be treated as the natural circular limit to GW phasing for spinning compact binaries in inspiraling eccentric orbits (Gopakumar A and Schäfer G 2011 Phys. Rev. D 84 124007). (paper)

  20. ISABELLE closed orbit correction system

    International Nuclear Information System (INIS)

    Parzen, G.

    1977-01-01

    The proposed closed orbit correction system for the ISABELLE storage accelerators is described. Results given include the initial orbit displacement error expected, the degree of correction that is expected by moving quadrupoles and by exciting dipole correction coils, the limitations on orbit correction due to the number and location of the probes (pick-up electrodes) and the accuracy requirements on the power supplies that stem primarily from the need to keep the two narrow beams in proper collision with each other

  1. Na Cl ion pair association in water-DMSO mixtures: Effect of ion pair ...

    Indian Academy of Sciences (India)

    ion pair in water–dimethyl sulfoxide (DMSO) mixtures for three DMSO mole fractions have been computed using constrained Molecular Dynamics (MD) simulations and confirmed by dynamical trajectories and residence times of the ion pair at various inter-ionic separations. The three ion-ion direct potentials used are 12-6-1 ...

  2. Orbital Eccrine Hidrocystoma

    Directory of Open Access Journals (Sweden)

    Deniz Marangoz

    2016-10-01

    Full Text Available A 29-year-old female patient presented with a painless mass on her upper eyelid medially. She noticed the mass 4 years earlier and it had increased in size over time. She had no diplopia, eyelid swelling, skin lesion overlying the mass, or visual disturbances. On ocular examination, eye movements and funduscopy were normal. The mass was movable and painless with palpation. Magnetic resonance imaging with contrast showed a 12x8x7 mm well-circumscribed cystic lesion with no contrast dye appearance. Surgical removal was performed delicately and no capsular rupture occured. Pathological examination revealed an eccrine hidrocystoma. Our aim is to underline that eccrine hidrocystoma should be included in differential diagnosis of orbital masses.

  3. Exploratory orbit analysis

    International Nuclear Information System (INIS)

    Michelotti, L.

    1989-03-01

    Unlike the other documents in these proceedings, this paper is neither a scientific nor a technical report. It is, rather, a short personal essay which attempts to describe an Exploratory Orbit Analysis (EOA) environment. Analyzing the behavior of a four or six dimensional nonlinear dynamical system is at least as difficult as analyzing events in high-energy collisions; the consequences of doing it badly, or slowly, would be at least as devastating; and yet the level of effort and expenditure invested in the latter, the very attention paid to it by physicists at large, must be two orders of magnitude greater than that given to the former. It is difficult to choose the model which best explains the behavior of a physical device if one does not first understand the behavior of the available models. The time is ripe for the development of a functioning EOA environment, which I will try to describe in this paper to help us achieve this goal

  4. Solitonic natural orbitals

    Science.gov (United States)

    Cioslowski, Jerzy

    2018-04-01

    The dependence of the natural amplitudes of the harmonium atom in its ground state on the confinement strength ω is thoroughly investigated. A combination of rigorous analysis and extensive, highly accurate numerical calculations reveals the presence of only one positive-valued natural amplitude ("the normal sign pattern") for all ω ≥1/2 . More importantly, it is shown that unusual, weakly occupied natural orbitals (NOs) corresponding to additional positive-valued natural amplitudes emerge upon sufficient weakening of the confinement. These solitonic NOs, whose shapes remain almost invariant as their radial positions drift toward infinity upon the critical values of ω being approached from below, exhibit strong radial localization. Their asymptotic properties are extracted from the numerical data and their relevance to calculations on fully Coulombic systems is discussed.

  5. Orbital myositis in scleritis

    Science.gov (United States)

    Boonman, Z F H M; de Keizer, R J W; Graniewski-Wijnands, H S; Watson, P G

    2003-01-01

    Aims: To investigate the association between scleritis and myositis. Methods: Retrospective, non-comparative case series. Records and ultrasonograms were examined of 132 patients, with a diagnosis of episcleritis or scleritis, who attended the ophthalmology department at Leiden University Medical Center between 1997 and 2000. 103 were eligible for comprehensive examination. Medical records were evaluated. Ultrasonography was performed in all patients diagnosed with episcleritis or scleritis. Clinical features, precipitating factors, systemic associations, ocular complications, treatment, and outcome of each patient were assessed. Results: Of the 103 patients, 27 (26.2%) had episcleritis and 76 (73.8%) had scleritis. Myositis was found to be present in 11 patients. It was present in 14.5% of all patients with scleritis and 30.5% of those in whom the posterior sclera was affected. The presence of the associated myositis did not worsen the visual prognosis and the presence of myositis was not associated with other systemic diseases. There were no cases of unilateral scleritis with bilateral orbital myositis. During an attack ocular complications were more common in patients with scleritis and myositis (64%) than in patients with scleritis alone (30.4%), indicating a more diffuse and potentially dangerous inflammation. There was no evidence that the inflammatory changes in the orbit had spread to involve the sclera, so it is assumed that the muscle changes are an extension of a generalised response to intense inflammation of the episclera and sclera. Conclusion: This study found a frequent association between myositis and scleritis. Prognosis for vision was not affected by coexistence of myositis. PMID:12488260

  6. Orbit Determination Toolbox

    Science.gov (United States)

    Carpenter, James R.; Berry, Kevin; Gregpru. Late; Speckman, Keith; Hur-Diaz, Sun; Surka, Derek; Gaylor, Dave

    2010-01-01

    The Orbit Determination Toolbox is an orbit determination (OD) analysis tool based on MATLAB and Java that provides a flexible way to do early mission analysis. The toolbox is primarily intended for advanced mission analysis such as might be performed in concept exploration, proposal, early design phase, or rapid design center environments. The emphasis is on flexibility, but it has enough fidelity to produce credible results. Insight into all flight dynamics source code is provided. MATLAB is the primary user interface and is used for piecing together measurement and dynamic models. The Java Astrodynamics Toolbox is used as an engine for things that might be slow or inefficient in MATLAB, such as high-fidelity trajectory propagation, lunar and planetary ephemeris look-ups, precession, nutation, polar motion calculations, ephemeris file parsing, and the like. The primary analysis functions are sequential filter/smoother and batch least-squares commands that incorporate Monte-Carlo data simulation, linear covariance analysis, measurement processing, and plotting capabilities at the generic level. These functions have a user interface that is based on that of the MATLAB ODE suite. To perform a specific analysis, users write MATLAB functions that implement truth and design system models. The user provides his or her models as inputs to the filter commands. The software provides a capability to publish and subscribe to a software bus that is compliant with the NASA Goddard Mission Services Evolution Center (GMSEC) standards, to exchange data with other flight dynamics tools to simplify the flight dynamics design cycle. Using the publish and subscribe approach allows for analysts in a rapid design center environment to seamlessly incorporate changes in spacecraft and mission design into navigation analysis and vice versa.

  7. The conservation of orbital symmetry

    CERN Document Server

    Woodward, R B

    2013-01-01

    The Conservation of Orbital Symmetry examines the principle of conservation of orbital symmetry and its use. The central content of the principle was that reactions occur readily when there is congruence between orbital symmetry characteristics of reactants and products, and only with difficulty when that congruence does not obtain-or to put it more succinctly, orbital symmetry is conserved in concerted reaction. This principle is expected to endure, whatever the language in which it may be couched, or whatever greater precision may be developed in its application and extension. The book ope

  8. CDDIS_DORIS_products_orbit

    Data.gov (United States)

    National Aeronautics and Space Administration — Precise satellite orbits derived from analysis of Doppler Orbitography by Radiopositioning Integrated on Satellite (DORIS) data. These products are the generated by...

  9. Modeling GPS satellite attitude variation for precise orbit determination

    Science.gov (United States)

    Kuang, D.; Rim, H. J.; Schutz, B. E.; Abusali, P. A. M.

    1996-09-01

    High precision geodetic applications of the Global Positioning System (GPS) require highly precise ephemerides of the GPS satellites. An accurate model for the non-gravitational forces on the GPS satellites is a key to high quality GPS orbit determination, especially in long arcs. In this paper the effect of the satellite solar panel orientation error is investigated. These effects are approximated by empirical functions to model the satellite attitude variation in long arc orbit fit. Experiments show that major part of the long arc GPS orbit errors can be accommodated by introducing a periodic variation of the satellite solar panel orientation with respect to the satellite-Sun direction, the desired direction for solar panel normal vector, with an amplitude of about 1 degree and with a frequency of once per orbit revolution.

  10. Ion colliders

    International Nuclear Information System (INIS)

    Fischer, W.

    2010-01-01

    Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions (77Asb1, 81Bou1). The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the

  11. Ion colliders

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, W.

    2011-12-01

    Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions [77Asb1, 81Bou1]. The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the

  12. Electron/photon matched field technique for treatment of orbital disease

    International Nuclear Information System (INIS)

    Arthur, Douglas W.; Zwicker, Robert D.; Garmon, Pamela W.; Huang, David T.; Schmidt-Ullrich, Rupert K.

    1997-01-01

    Purpose: A number of approaches have been described in the literature for irradiation of malignant and benign diseases of the orbit. Techniques described to date do not deliver a homogeneous dose to the orbital contents while sparing the cornea and lens of excessive dose. This is a result of the geometry encountered in this region and the fact that the target volume, which includes the periorbital and retroorbital tissues but excludes the cornea, anterior chamber, and lens, cannot be readily accommodated by photon beams alone. To improve the dose distribution for these treatments, we have developed a technique that combines a low-energy electron field carefully matched with modified photon fields to achieve acceptable dose coverage and uniformity. Methods and Materials: An anterior electron field and a lateral photon field setup is used to encompass the target volume. Modification of these fields permits accurate matching as well as conformation of the dose distribution to the orbit. A flat-surfaced wax compensator assures uniform electron penetration across the field, and a sunken lead alloy eye block prevents excessive dose to the central structures of the anterior segment. The anterior edge of the photon field is modified by broadening the penumbra using a form of pseudodynamic collimation. Direct measurements using film and ion chamber dosimetry were used to study the characteristics of the fall-off region of the electron field and the penumbra of the photon fields. >From the data collected, the technique for accurate field matching and dose uniformity was generated. Results: The isodose curves produced with this treatment technique demonstrate homogeneous dose coverage of the orbit, including the paralenticular region, and sufficient dose sparing of the anterior segment. The posterior lens accumulates less than 40% of the prescribed dose, and the lateral aspect of the lens receives less than 30%. A dose variation in the match region of ±12% is confronted when

  13. Tunneling anisotropic magnetoresistance via molecular π orbitals of Pb dimers

    Science.gov (United States)

    Schöneberg, Johannes; Ferriani, Paolo; Heinze, Stefan; Weismann, Alexander; Berndt, Richard

    2018-01-01

    Pb dimers on a ferromagnetic surface are shown to exhibit large tunneling anisotropic magnetoresistance (TAMR) due to molecular π orbitals. Dimers oriented differently with respect to the magnetization directions of a ferromagnetic Fe double layer on W(110) were made with a scanning tunneling microscope. Depending on the dimer orientations, TAMR is absent or as large as 20% at the Fermi level. General arguments and first-principles calculations show that mixing of molecular orbitals due to spin-orbit coupling, which leads to TAMR, is maximal when the magnetization is oriented parallel to the dimer axis.

  14. [Functional and cosmetic relevance of primary orbital implants].

    Science.gov (United States)

    Kohlhaas, Markus; Schulz, Dominic

    2003-06-01

    Orbital implants are used to prevent post-enucleation-syndromes and to improve prosthesis motility. 20 patients without and 32 patients with orbital implants were examined 6 to 14 years after enucleation. Maximum prosthesis motility in 4 directions, width of the palpebral fissure and vertical difference of the eye axis were measured using Kestenbaum glasses. The apex of the prosthesis was measured with a Hertel exophthalmometer. The post-enucleation-syndrome was assessed by a 4 point scale by the investigators. Post-enucleation-syndromes are significantly (p 0.05) altered. Primary orbital implants allow for prevention of a post-enucleation-syndrome and a better functional and cosmetic outcome.

  15. Resonantly enhanced inner-orbital ionization in molecular iodine

    Science.gov (United States)

    Smith, Dale L.; Gibson, George N.

    2018-02-01

    We present a wavelength study of the strong-field single-electron ionization of molecular iodine near its one-photon B -state resonance at 530 nm. We have previously identified two ionization channels [Phys. Rev. A 95, 013410 (2017), 10.1103/PhysRevA.95.013410]: ionization of the high-lying molecular orbitals and ionization of the deep orbitals in I2. We find a resonant enhancement of both channels, although the peak enhancement occurs at different wavelengths for the different channels. Moreover, the branching ratio of the ionization of the deep orbitals shows a dispersion-like function, with the branching ratio of the deep orbitals reaching over 98% at 519 nm. Finally, the branching ratio of double ionization into an excited state of I22+ as a function of wavelength closely matches the branching ratio of the single ionization of deep orbitals, implying that excitation of molecular ions generally comes about through inner orbital ionization. These findings are inconsistent with current molecular ionization theory.

  16. PyORBIT: A Python Shell For ORBIT

    International Nuclear Information System (INIS)

    Jean-Francois Ostiguy; Jeffrey Holmes

    2003-01-01

    ORBIT is code developed at SNS to simulate beam dynamics in accumulation rings and synchrotrons. The code is structured as a collection of external C++ modules for SuperCode, a high level interpreter shell developed at LLNL in the early 1990s. SuperCode is no longer actively supported and there has for some time been interest in replacing it by a modern scripting language, while preserving the feel of the original ORBIT program. In this paper, we describe a new version of ORBIT where the role of SuperCode is assumed by Python, a free, well-documented and widely supported object-oriented scripting language. We also compare PyORBIT to ORBIT from the standpoint of features, performance and future expandability

  17. Orbital Chondroma: A rare mesenchymal tumor of orbit

    Directory of Open Access Journals (Sweden)

    Ruchi S Kabra

    2015-01-01

    Full Text Available While relatively common in the skeletal system, cartilaginous tumors are rarely seen originating from the orbit. Here, we report a rare case of an orbital chondroma. A 27-year-old male patient presented with a painless hard mass in the superonasal quadrant (SNQ of left orbit since 3 months. On examination, best-corrected visual acuity of both eyes was 20/20, with normal anterior and posterior segment with full movements of eyeballs and normal intraocular pressure. Computerized tomography scan revealed well defined soft tissue density lesion in SNQ of left orbit. Patient was operated for anteromedial orbitotomy under general anesthesia. Mass was excised intact and sent for histopathological examination (HPE. HPE report showed lobular aggregates of benign cartilaginous cells with mild atypia suggesting of benign cartilaginous tumor - chondroma. Very few cases of orbital chondroma have been reported in literature so far.

  18. PyORBIT: A Python Shell For ORBIT

    Energy Technology Data Exchange (ETDEWEB)

    Jean-Francois Ostiguy; Jeffrey Holmes

    2003-07-01

    ORBIT is code developed at SNS to simulate beam dynamics in accumulation rings and synchrotrons. The code is structured as a collection of external C++ modules for SuperCode, a high level interpreter shell developed at LLNL in the early 1990s. SuperCode is no longer actively supported and there has for some time been interest in replacing it by a modern scripting language, while preserving the feel of the original ORBIT program. In this paper, we describe a new version of ORBIT where the role of SuperCode is assumed by Python, a free, well-documented and widely supported object-oriented scripting language. We also compare PyORBIT to ORBIT from the standpoint of features, performance and future expandability.

  19. Li-Ion Battery Studies at NASA/Goddard Space Flight Center

    Science.gov (United States)

    Lee, Leonine; Rao, Gopalakrishna M.

    2006-01-01

    This viewgraph presentation reviews NASA and GSFC's interest in Lithium Ion Batteries as power suupplies for space usage, the tests, and results on several commercially available batteries. Severl batteries were tested for Geosynchronous orbit, Low Earth Orbit, and Low Lunar Orbit conditions.

  20. Ion funnel device

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, Yehia M.; Chen, Tsung-Chi; Harrer, Marques B.; Tang, Keqi; Smith, Richard D.

    2017-11-21

    An ion funnel device is disclosed. A first pair of electrodes is positioned in a first direction. A second pair of electrodes is positioned in a second direction. The device includes an RF voltage source and a DC voltage source. A RF voltage with a superimposed DC voltage gradient is applied to the first pair of electrodes, and a DC voltage gradient is applied to the second pair of electrodes.

  1. Parametric studies of electric propulsion systems for orbit transfer vehicles

    Science.gov (United States)

    Manvi, R.; Fujita, T.

    1988-01-01

    The present parametric tradeoff study for OTV electric propulsion systems encompasses ammonia and hydrogen arcjets as well as Xe-ion propulsion systems with performance characteristics currently being projected for 1993 operation. In all cases, the power source is a nuclear-electric system with 30 kg/kW(e) specific mass, and the mission involves the movement of payloads from lower orbits to GEO. Attention is given to payload capabilities and associated propellant requirements. Mission trip time is identified as the key parameter for selection; while arcjets are preferable for shorter trip times, ion propulsion is more advantageous for longer trip times due to reduced propellant mass fraction.

  2. Plasmablastic lymphoma mimicking orbital cellulitis.

    NARCIS (Netherlands)

    Barkhuysen, R.; Merkx, M.A.W.; Weijs, W.L.J.; Gerlach, N.L.; Berge, S.J.

    2008-01-01

    INTRODUCTION: Orbital cellulitis is an uncommon, potentially devastating condition that, when not promptly and adequately treated, can lead to serious sequelae. The presenting clinical signs are proptosis, swelling, ophthalmoplegia, pain and redness of the peri-orbital tissues. A number of cases

  3. Generating realistic synthetic meteoroid orbits

    Science.gov (United States)

    Vida, Denis; Brown, Peter G.; Campbell-Brown, Margaret

    2017-11-01

    Context. Generating a synthetic dataset of meteoroid orbits is a crucial step in analysing the probabilities of random grouping of meteoroid orbits in automated meteor shower surveys. Recent works have shown the importance of choosing a low similarity threshold value of meteoroid orbits, some pointing out that the recent meteor shower surveys produced false positives due to similarity thresholds which were too high. On the other hand, the methods of synthetic meteoroid orbit generation introduce additional biases into the data, thus making the final decision on an appropriate threshold value uncertain. Aims. As a part of the ongoing effort to determine the nature of meteor showers and improve automated methods, it was decided to tackle the problem of synthetic meteoroid orbit generation, the main goal being to reproduce the underlying structure and the statistics of the observed data in the synthetic orbits. Methods. A new method of generating synthetic meteoroid orbits using the Kernel Density Estimation method is presented. Several types of approaches are recommended, depending on whether one strives to preserve the data structure, the data statistics or to have a compromise between the two. Results. The improvements over the existing methods of synthetic orbit generation are demonstrated. The comparison between the previous and newly developed methods are given, as well as the visualization tools one can use to estimate the influence of different input parameters on the final data.

  4. Endoscopic treatment of orbital tumors.

    Science.gov (United States)

    Signorelli, Francesco; Anile, Carmelo; Rigante, Mario; Paludetti, Gaetano; Pompucci, Angelo; Mangiola, Annunziato

    2015-03-16

    Different orbital and transcranial approaches are performed in order to manage orbital tumors, depending on the location and size of the lesion within the orbit. These approaches provide a satisfactory view of the superior and lateral aspects of the orbit and the optic canal but involve risks associated with their invasiveness because they require significant displacement of orbital structures. In addition, external approaches to intraconal lesions may also require deinsertion of extraocular muscles, with subsequent impact on extraocular mobility. Recently, minimally invasive techniques have been proposed as valid alternative to external approaches for selected orbital lesions. Among them, transnasal endoscopic approaches, "pure" or combined with external approaches, have been reported, especially for intraconal lesions located inferiorly and medially to the optic nerve. The avoidance of muscle detachment and the shortness of the surgical intraorbital trajectory makes endoscopic approach less invasive, thus minimizing tissue damage. Endoscopic surgery decreases the recovery time and improves the cosmetic outcome not requiring skin incisions. The purpose of this study is to review and discuss the current surgical techniques for orbital tumors removal, focusing on endoscopic approaches to the orbit and outlining the key anatomic principles to follow for safe tumor resection.

  5. [Enophthalmos in an orbital tumor].

    Science.gov (United States)

    Szabo, Bianca; Szabo, I; Nicula, Cristina; Popescu, Livia Adriana

    2013-01-01

    Enophtalmus is an unusual sign of the orbital tumors often represented by proptosis. One patient with enophtalmus and intraorbital tumor and aplasy is presented. The treatment of choice of orbital tumor is complete surgical excision and careful follow-up. Considering the more aggressive course followed by recurrent tumor, correct diagnosis and management is essential.

  6. Diplopia and Orbital Wall Fractures

    NARCIS (Netherlands)

    Boffano, P.; Roccia, F.; Gallesio, C.; Karagozoglu, K.H.; Forouzanfar, T.

    2014-01-01

    Diplopia is a symptom that is frequently associated with orbital wall fractures. The aim of this article was to present the incidence and patterns of diplopia after orbital wall blow-out fractures in 2 European centers, Turin and Amsterdam, and to identify any correlation between this symptom and

  7. Diplopia and orbital wall fractures

    NARCIS (Netherlands)

    Boffano, P.; Roccia, F.; Gallesio, C.; Karagozoglu, K.H.; Forouzanfar, T.

    2014-01-01

    Diplopia is a symptom that is frequently associated with orbital wall fractures. The aim of this article was to present the incidence and patterns of diplopia after orbital wall blow-out fractures in 2 European centers, Turin and Amsterdam, and to identify any correlation between this symptom and

  8. Spin Orbit Torque in Ferromagnetic Semiconductors

    KAUST Repository

    Li, Hang

    2016-06-21

    effect on spin orbit torque in nanoribbons with a hexagonal lattice. We find a dramatic modification of the nature of the torque (field like and damping-like component) when crossing the topological phase transition. The relative agnitude of the two torque components can be significantly modifies by changing the magnetization direction. Finally, motivated by recent experimental results, we conclude by investigating the features of spin-orbit torque in magnetic transition metal dichalcogenides. We find the torque is associated with the valley polarization. By changing the magnetization direction, the torque can be changed from a finite value to zero when the valley polarization decreases from a finite value to zero.

  9. Orbital physics in sulfur spinels: ordered, liquid and glassy ground states

    International Nuclear Information System (INIS)

    Buettgen, N; Hemberger, J; Fritsch, V; Krimmel, A; Muecksch, M; Nidda, H-A Krug von; Lunkenheimer, P; Fichtl, R; Tsurkan, V; Loidl, A

    2004-01-01

    Measurements of magnetization M(T, H), heat capacity C(T), NMR lineshift K(T) and linewidth Δ(T), neutron scattering S(Q, ω, T) and broadband dielectric spectroscopy ε(ω, T) provide experimental evidence of the different orbital ground states in the cubic sulfur spinels under investigation. In all compounds, the tetrahedrally coordinated Jahn-Teller ions Fe 2+ are characterized by a degeneracy of the orbital degrees of freedom. Particularly, we found a long-range orbital ordering in polycrystalline (PC) FeCr 2 S 4 , and a glassy freezing of the orbital degrees of freedom in FeCr 2 S 4 (single crystals) (SCs). In contrast, FeSc 2 S 4 belongs to the rare class of spin-orbital liquids, where quantum fluctuations accompanying the glassy freezing of the orbitals suppress long-range magnetic order

  10. Plasmablastic lymphoma mimicking orbital cellulitis

    Science.gov (United States)

    Merkx, Matthias A. W.; Weijs, Willem L. J.; Gerlach, Niek L.; Bergé, Stefaan J.

    2008-01-01

    Introduction Orbital cellulitis is an uncommon, potentially devastating condition that, when not promptly and adequately treated, can lead to serious sequelae. The presenting clinical signs are proptosis, swelling, ophthalmoplegia, pain and redness of the peri-orbital tissues. A number of cases have been reported in which these symptoms have been mistakenly interpreted as being secondary to an orbital infection whilst, in fact, other pathology was present. Discussion We add another case in which, on clinical grounds and after radiological assessment and laboratory tests, a working diagnosis of orbital cellulitis of the left eye was made. It was only after histopathological analysis of a soft tissue specimen from the maxillary sinus that a diagnosis of an AIDS-related plasmablastic lymphoma was made. The patient was referred to the department of haematology where chemotherapeutic treatment for the lymphoma and the HIV infection was started. This case report adds another differential diagnosis of orbital cellulitis to the existing literature. PMID:18597126

  11. A comparison of potential electric propulsion systems for orbit transfer

    Science.gov (United States)

    Jones, R. M.

    1982-01-01

    Electric propulsion concepts are compared on the basis of trip time for the low earth orbit (LEO) to geosynchronous earth orbit (GEO) mission. Resistojet, arcjet, magnetoplasmadynamic (MPD), pulsed inductive, and ion engine thruster concepts are included. The optimum (minimum trip time) value of specific impulse is found to be dependent upon the specific mission and system being considered. As expected, the devices which can deliver good efficiency at low specific impulses promise the fastest trip times. The solution for trip time and propellant mass for the constant power, continuous low acceleration orbit transfer problem (one way and round trip) is presented in nomograph form. The influences of mission Delta V, thruster efficiency, specific impulse, power, power and propulsion system mass, and payload mass are clearly illustrated.

  12. The average orbit system upgrade for the Brookhaven AGS

    International Nuclear Information System (INIS)

    Ciardullo, D.J.; Brennan, J.M.

    1995-01-01

    The flexibility of the AGS to accelerate protons, polarized protons and heavy ions requires average orbit instrumentation capable of performing over a wide range of beam intensity (10 9 to 6 x 10 13 charges) and accelerating frequency (1.7MHz to 4.5MHz). In addition, the system must be tolerant of dramatic changes in bunch shape, such as those occurring near transition. Reliability and maintenance issues preclude the use of active electronics within the high radiation environment of the AGS tunnel, prompting the use of remote bunch signal processing. The upgrade for the AGS Average Orbit system is divided into three areas: (1) a new Pick Up Electrode (PUE) signal delivery system; (2) new average orbit processing electronics; and (3) centralized peripheral and data acquisition hardware. A distributed processing architecture was chosen to minimize the PUE signal cable lengths, the group of four from each detector location being phase matched to within ±5 degree

  13. Angles-Only Initial Relative Orbit Determination Performance Analysis using Cylindrical Coordinates

    Science.gov (United States)

    Geller, David K.; Lovell, T. Alan

    2017-03-01

    The solution of the initial relative orbit determination problem using angles-only measurements is important for orbital proximity operations, satellite inspection and servicing, and the identification of unknown space objects in similar orbits. In this paper, a preliminary relative orbit determination performance analysis is conducted utilizing the linearized relative orbital equations of motion in cylindrical coordinates. The relative orbital equations of motion in cylindrical coordinates are rigorously derived in several forms included the exact nonlinear two-body differential equations of motion, the linear-time-varying differential equations of motion for an elliptical orbit chief, and the linear-time-invariant differential equations of motion for a circular orbit chief. Using the nonlinear angles-only measurement equation in cylindrical coordinates, evidence of full-relative-state observability is found, contrary to the range observability problem exhibited in Cartesian coordinates. Based on these results, a geometric approach to assess initial relative orbit determination performance is formulated. To facilitate a better understanding of the problem, the focus is on the 2-dimensional initial orbit determination problem. The results clearly show the dependence of the relative orbit determination performance on the geometry of the relative motion and on the time-interval between observations. Analysis is conducted for leader-follower orbits and flyby orbits where the deputy passes directly above or below the chief.

  14. ion irradiation

    Indian Academy of Sciences (India)

    Swift heavy ions interact predominantly through inelastic scattering while traversing any polymer medium and produce excited/ionized atoms. Here samples of the polycarbonate Makrofol of approximate thickness 20 m, spin coated on GaAs substrate were irradiated with 50 MeV Li ion (+3 charge state). Build-in ...

  15. Cassini MIMI Close-Up of Saturn Energetic Particles: Low Altitude Trapped Radiation, Auroral Ion Acceleration, and Interchange Flow Channels

    Science.gov (United States)

    Mitchell, D. G.; Krimigis, S. M.; Krupp, N.; Paranicas, C.; Roussos, E.; Kollmann, P.

    2017-12-01

    We present observations from the final orbits of the Cassini Mission at Saturn by the Magnetospheric Imaging Instrument (MIMI). Crossing inside the D-Ring at the equator and just above Saturn's atmosphere, these orbits covered regions never visited previously in the mission. Highlights include the confirmation of an inner radiation belt analogous to the inner radiation belt at Earth by the Low Energy Magnetospheric Measurement System (LEMMS), with surprising twists—Saturn's D-ring material appears to be a source for these particles. Details will be presented in another session. The Grand Finale orbits also afforded a close-up view of the auroral ion acceleration regions by the Ion and Neutral Camera (INCA). Ionospheric ions at the base of auroral field lines are accelerated perpendicular to the magnetic field to 10's and 100's of keV, and charge exchange with exospheric neutrals to be emitted as energetic neutral atoms and images by INCA. We show that this acceleration region lies at about 0.1 Rs. Another feature seen previously in the mission but imaged with greater resolution is a flow channel associated with interchange motion in the middle magnetosphere. We show this feature to extend over several Saturn radii in the radial direction, and over about 2 Saturn radii azimuthally. Additional data have been received since the writing of this abstract and before Cassini's plunge into the atmosphere on September 15, so additional features may be presented.

  16. Several topics on orbital dynamics of consecutive, low-thrust, accelerated spacecraft trajectories

    OpenAIRE

    Yamakawa, Hiroshi; 山川 宏

    2008-01-01

    Orbital dynamics of consecutive, low-thrust trajectories is overviewed. Focusing on the thrust direction constraints (e.g., transversal and radial thrust direction constraints), various trajectory design strategies of low-thrust missions are summarized with concrete examples.

  17. Orbital motions as gradiometers for post-Newtonian tidal effects

    Energy Technology Data Exchange (ETDEWEB)

    Iorio, Lorenzo, E-mail: lorenzo.iorio@libero.it [Ministero dell' Istruzione, dell' Università e della Ricerca, Istruzione, Bari (Italy)

    2014-08-14

    The direct long-term changes occurring in the orbital dynamics of a local gravitationally bound binary system S due to the post-Newtonian tidal acceleration caused by an external massive source are investigated. A class of systems made of a test particle m rapidly orbiting with orbital frequency n{sub b} an astronomical body of mass M which, in turn, slowly revolves around a distant object of mass M′ with orbital frequency n{sub b}′ « n{sub b} is considered. The characteristic frequencies of the non-Keplerian orbital variations of m and of M itself are assumed to be negligible with respect to both n{sub b} and n{sub b}′. General expressions for the resulting Newtonian and post-Newtonian tidal orbital shifts of m are obtained. The future missions BepiColombo and JUICE to Mercury and Ganymede, respectively, are considered in view of a possible detection. The largest effects, of the order of ≈ 0.1-0.5 milliarcseconds per year (mas yr{sup −1}), occur for the Ganymede orbiter of the JUICE mission. Although future improvements in spacecraft tracking and orbit determination might, perhaps, reach the required sensitivity, the systematic bias represented by the other known orbital perturbations of both Newtonian and post-Newtonian origin would be overwhelming. The realization of a dedicated artificial mini-planetary system to be carried onboard and Earth-orbiting spacecraft is considered as well. Post-Newtonian tidal precessions as large as ≈ 1−10{sup 2} mas yr{sup −1} could be obtained, but the quite larger Newtonian tidal effects would be a major source of systematic bias because of the present-day percent uncertainty in the product of the Earth's mass times the Newtonian gravitational parameter.

  18. Solid Propulsion De-Orbiting and Re-Orbiting

    Science.gov (United States)

    Schonenborg, R. A. C.; Schoyer, H. F. R.

    2009-03-01

    With many "innovative" de-orbit systems (e.g. tethers, aero breaking, etc.) and with natural de-orbit, the place of impact of unburned spacecraft debris on Earth can not be determined accurately. The idea that satellites burn up completely upon re-entry is a common misunderstanding. To the best of our knowledge only rocket motors are capable of delivering an impulse that is high enough, to conduct a de-orbit procedure swiftly, hence to de-orbit at a specific moment that allows to predict the impact point of unburned spacecraft debris accurately in remote areas. In addition, swift de-orbiting will reduce the on-orbit time of the 'dead' satellite, which reduces the chance of the dead satellite being hit by other dead or active satellites, while spiralling down to Earth during a slow, 25 year, or more, natural de-orbit process. Furthermore the reduced on-orbit time reduces the chance that spacecraft batteries, propellant tanks or other components blow up and also reduces the time that the object requires tracking from Earth.The use of solid propellant for the de-orbiting of spacecraft is feasible. The main advantages of a solid propellant based system are the relatively high thrust and the facts that the system can be made autonomous quite easily and that the system can be very reliable. The latter is especially desirable when one wants to de-orbit old or 'dead' satellites that might not be able to rely anymore on their primary systems. The disadvantage however, is the addition of an extra system to the spacecraft as well as a (small) mass penalty. [1]This paper describes the above mentioned system and shows as well, why such a system can also be used to re-orbit spacecraft in GEO, at the end of their life to a graveyard orbit.Additionally the system is theoretically compared to an existing system, of which performance data is available.A swift market analysis is performed as well.

  19. RHIC 10 Hz global orbit feedback system

    International Nuclear Information System (INIS)

    Michnoff, R.; Arnold, L.; Carboni, L.; Cerniglia, P.; Curcio, A.; DeSanto, L.; Folz, C.; Ho, C.; Hoff, L.; Hulsart, R.; Karl, R.; Luo, Y.; Liu, C.; MacKay, W.; Mahler, G.; Meng, W.; Mernick, K.; Minty, M.; Montag, C.; Olsen, R.; Piacentino, J.; Popken, P.; Przybylinski, R.; Ptitsyn, V.; Ritter, J.; Schoenfeld, R.; Thieberger, P.; Tuozzolo, J.; Weston, A.; White, J.; Ziminski, P.; Zimmerman, P.

    2011-01-01

    Vibrations of the cryogenic triplet magnets at the Relativistic Heavy Ion Collider (RHIC) are suspected to be causing the horizontal beam perturbations observed at frequencies around 10 Hz. Several solutions to counteract the effect have been considered in the past, including a local beam feedback system at each of the two experimental areas, reinforcing the magnet base support assembly, and a mechanical servo feedback system. However, the local feedback system was insufficient because perturbation amplitudes outside the experimental areas were still problematic, and the mechanical solutions are very expensive. A global 10 Hz orbit feedback system consisting of 36 beam position monitors (BPMs) and 12 small dedicated dipole corrector magnets in each of the two 3.8 km circumference counter-rotating rings has been developed and commissioned in February 2011. A description of the system architecture and results with beam will be discussed.

  20. Collective focusing ion accelerator

    International Nuclear Information System (INIS)

    Goldin, F.J.

    1986-01-01

    The principal subject of this dissertation is the trapping confinement of pure electron plasmas in bumpy toroidal magnetic fields, with particular attention given to the trapping procedure and the behavior of the plasma during the final equilibrium. The most important aspects of the equilibrium studied were the qualitative nature of the plasma configuration and motion and its density, distribution and stability. The motivation for this study was that an unneutralized cloud of electrons contained in a toroidal system, sufficiently dense and stable, may serve to electrostatically focus ions (against centrifugal and self space charge forces) in a cyclic ion accelerator. Such an accelerator, known as a Collective Focusing Ion Accelerator (CFIA) could be far smaller than conventional designs (which use external magnetic fields directly to focus the ions) due to the smaller gyro-radium of an electron in a magnetic field of given strength. The electron cloud generally drifted poloidally at a finite radius from the toroidal minor axis. As this would preclude focusing ions with such clouds, damping this motion was investigated. Finite resistance in the normally perfectly conductive vessel wall did this. In further preparation for a working CFIA, additional experiments studied the effect of ions on the stability of the electron cloud

  1. 2010 ion run: completed!

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    After a very fast switchover from protons to lead ions, the LHC has achieved performances that allowed the machine to exceed both peak and integrated luminosity by a factor of three. Thanks to this, experiments have been able to produce high-profile results on ion physics almost immediately, confirming that the LHC was able to keep its promises for ions as well as for protons.   First direct observation of jet quenching. A seminar on 2 December was the opportunity for the ALICE, ATLAS and CMS collaborations to present their first results on ion physics in front of a packed auditorium. These results are important and are already having a major impact on the understanding of the physics processes that involve the basic constituents of matter at high energies. In the ion-ion collisions, the temperature is so high that partons (quarks and gluons), which are usually constrained inside the nucleons, are deconfined to form a highly dense and hot soup known as quark-gluon plasma (QGP). The existence of ...

  2. Rehabilitation of orbital cavity after orbital exenteration using polymethyl methacrylate orbital prosthesis.

    Science.gov (United States)

    Jain, Sumeet; Jain, Parul

    2016-01-01

    Squamous cell carcinoma of the eyelid is the second most common malignant neoplasm of the eye with the incidence of 0.09 and 2.42 cases/100 000 people. Orbital invasion is a rare complication but, if recognized early, can be treated effectively with exenteration. Although with advancements in technology such as computer-aided design and computer-aided manufacturing, material science, and retentive methods like implants, orbital prosthesis with stock ocular prosthesis made of methyl methacrylate retained by anatomic undercuts is quiet effective and should not be overlooked and forgotten. This clinical report describes prosthetic rehabilitation of two male patients with polymethyl methacrylate resin orbital prosthesis after orbital exenteration, for squamous cell carcinoma of the upper eyelid. The orbital prosthesis was sufficiently retained by hard and soft tissue undercuts without any complications. The patients using the prosthesis are quite satisfied with the cosmetic results and felt comfortable attending the social events.

  3. Rehabilitation of orbital cavity after orbital exenteration using polymethyl methacrylate orbital prosthesis

    Directory of Open Access Journals (Sweden)

    Sumeet Jain

    2016-01-01

    Full Text Available Squamous cell carcinoma of the eyelid is the second most common malignant neoplasm of the eye with the incidence of 0.09 and 2.42 cases/100 000 people. Orbital invasion is a rare complication but, if recognized early, can be treated effectively with exenteration. Although with advancements in technology such as computer-aided design and computer-aided manufacturing, material science, and retentive methods like implants, orbital prosthesis with stock ocular prosthesis made of methyl methacrylate retained by anatomic undercuts is quiet effective and should not be overlooked and forgotten. This clinical report describes prosthetic rehabilitation of two male patients with polymethyl methacrylate resin orbital prosthesis after orbital exenteration, for squamous cell carcinoma of the upper eyelid. The orbital prosthesis was sufficiently retained by hard and soft tissue undercuts without any complications. The patients using the prosthesis are quite satisfied with the cosmetic results and felt comfortable attending the social events.

  4. Orbital Infarction due to Sickle Cell Disease without Orbital Pain

    Directory of Open Access Journals (Sweden)

    Cameron L. McBride

    2016-01-01

    Full Text Available Sickle cell disease is a hemoglobinopathy that results in paroxysmal arteriolar occlusion and tissue infarction that can manifest in a plurality of tissues. Rarely, these infarcted crises manifest in the bony orbit. Orbital infarction usually presents with acute onset of periorbital tenderness, swelling, erythema, and pain. Soft tissue swelling can result in proptosis and attenuation of extraocular movements. Expedient diagnosis of sickle cell orbital infarction is crucial because this is a potentially sight-threatening entity. Diagnosis can be delayed since the presentation has physical and radiographic findings mimicking various infectious and traumatic processes. We describe a patient who presented with sickle cell orbital crisis without pain. This case highlights the importance of maintaining a high index of suspicion in patients with known sickle cell disease or of African descent born outside the United States in a region where screening for hemoglobinopathy is not routine, even when the presentation is not classic.

  5. SPHERES Mars Orbiting Sample Return External Orbiting Capture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's Mars Sample Return (MSR) mission scenario utilizes a small Orbiting Sample (OS) satellite, launched from the surface of Mars, which will rendezvous with an...

  6. Rotation characteristics of main ions and impurity ions in H-mode tokamak plasma

    International Nuclear Information System (INIS)

    Kim, J.; Burrell, K.H.; Gohil, P.; Groebner, R.J.; Kim, Y.; St. John, H.E.; Seraydarian, R.P.; Wade, M.R.

    1994-01-01

    Poloidal and toroidal rotation of the main ions (He 2+ ) and the impurity ions (C 6+ and B 5+ ) in H-mode helium plasmas have been measured via charge exchange recombination spectroscopy in the DIII-D tokamak. It was discovered that the main ion poloidal rotation is in the ion diamagnetic drift direction while the impurity ion rotation is in the electron diamagnetic drift direction, in qualitative agreement with the neoclassical theory. The deduced radial electric field in the edge is of the same negative-well shape regardless of which ion species is used, validating the fundamental nature of the electric field in L-H transition phenomenology

  7. Orbital soft-tissue trauma.

    Science.gov (United States)

    Chazen, J Levi; Lantos, Joshua; Gupta, Ajay; Lelli, Gary J; Phillips, C Douglas

    2014-08-01

    In the clinical assessment of orbital trauma, visual acuity and extraocular muscle motility are critical for rapid evaluation of injury severity. However, assessment of these parameters may be limited by edema and concomitant injuries. Imaging may further delineate the trauma pattern and extent of injury. This review focuses on orbital soft-tissue injuries that can exist with or without orbital fracture. Imaging techniques and soft-tissue injuries, including those involving the anterior chamber, iris and ciliary body, lens, globe, posterior segment, and optic nerve, are reviewed, in addition to intraocular foreign bodies and cavernous-carotid fistulas. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Laser induced direct implantation of ions

    Czech Academy of Sciences Publication Activity Database

    Láska, Leoš; Juha, Libor; Krása, Josef; Mašek, Karel; Pfeifer, Miroslav; Rohlena, Karel; Králiková, Božena; Skála, Jiří; Peřina, Vratislav; Hnatowicz, Vladimír; Woryna, E.; Wolowski, J.; Parys, P.; Boody, F. P.; Hoepfl, R.; Hora, H.

    2000-01-01

    Roč. 50, S3 (2000), s. 81-90 ISSN 0011-4626 R&D Projects: GA AV ČR IAA1010819; GA ČR GA202/97/0444; GA ČR GA202/98/1274 Institutional research plan: CEZ:AV0Z1010921 Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.298, year: 2000

  9. JSC Orbital Debris Website Description

    Science.gov (United States)

    Johnson, Nicholas L.

    2006-01-01

    Purpose: The website provides information about the NASA Orbital Debris Program Office at JSC, which is the lead NASA center for orbital debris research. It is recognized world-wide for its leadership in addressing orbital debris issues. The NASA Orbital Debris Program Office has taken the international lead in conducting measurements of the environment and in developing the technical consensus for adopting mitigation measures to protect users of the orbital environment. Work at the center continues with developing an improved understanding of the orbital debris environment and measures that can be taken to control its growth. Major Contents: Orbital Debris research is divided into the following five broad efforts. Each area of research contains specific information as follows: 1) Modeling - NASA scientists continue to develop and upgrade orbital debris models to describe and characterize the current and future debris environment. Evolutionary and engineering models are described in detail. Downloadable items include a document in PDF format and executable software. 2) Measurements - Measurements of near-Earth orbital debris are accomplished by conducting ground-based and space-based observations of the orbital debris environment. The data from these sources provide validation of the environment models and identify the presence of new sources. Radar, optical and surface examinations are described. External links to related topics are provided. 3) Protection - Orbital debris protection involves conducting hypervelocity impact measurements to assess the risk presented by orbital debris to operating spacecraft and developing new materials and new designs to provide better protection from the environment with less weight penalty. The data from this work provides the link between the environment defined by the models and the risk presented by that environment to operating spacecraft and provides recommendations on design and operations procedures to reduce the risk as

  10. Iterative diagonalization for orbital optimization in natural orbital functional theory.

    Science.gov (United States)

    Piris, M; Ugalde, J M

    2009-10-01

    A challenging task in natural orbital functional theory is to find an efficient procedure for doing orbital optimization. Procedures based on diagonalization techniques have confirmed its practical value since the resulting orbitals are automatically orthogonal. In this work, a new procedure is introduced, which yields the natural orbitals by iterative diagonalization of a Hermitian matrix F. The off-diagonal elements of the latter are determined explicitly from the hermiticity of the matrix of the Lagrange multipliers. An expression for diagonal elements is absent so a generalized Fockian is undefined in the conventional sense, nevertheless, they may be determined from an aufbau principle. Thus, the diagonal elements are obtained iteratively considering as starting values those coming from a single diagonalization of the matrix of the Lagrange multipliers calculated with the Hartree-Fock orbitals after the occupation numbers have been optimized. The method has been tested on the G2/97 set of molecules for the Piris natural orbital functional. To help the convergence, we have implemented a variable scaling factor which avoids large values of the off-diagonal elements of F. The elapsed times of the computations required by the proposed procedure are compared with a full sequential quadratic programming optimization, so that the efficiency of the method presented here is demonstrated. Copyright 2009 Wiley Periodicals, Inc.

  11. Spin-orbit torques in magnetic bilayers

    Science.gov (United States)

    Haney, Paul

    2015-03-01

    Spintronics aims to utilize the coupling between charge transport and magnetic dynamics to develop improved and novel memory and logic devices. Future progress in spintronics may be enabled by exploiting the spin-orbit coupling present at the interface between thin film ferromagnets and heavy metals. In these systems, applying an in-plane electrical current can induce magnetic dynamics in single domain ferromagnets, or can induce rapid motion of domain wall magnetic textures. There are multiple effects responsible for these dynamics. They include spin-orbit torques and a chiral exchange interaction (the Dzyaloshinskii-Moriya interaction) in the ferromagnet. Both effects arise from the combination of ferromagnetism and spin-orbit coupling present at the interface. There is additionally a torque from the spin current flux impinging on the ferromagnet, arising from the spin hall effect in the heavy metal. Using a combination of approaches, from drift-diffusion to Boltzmann transport to first principles methods, we explore the relative contributions to the dynamics from these different effects. We additionally propose that the transverse spin current is locally enhanced over its bulk value in the vicinity of an interface which is oriented normal to the charge current direction.

  12. Charge Breeding of Radioactive Ions

    CERN Document Server

    Wenander, F J C

    2013-01-01

    Charge breeding is a technique to increase the charge state of ions, in many cases radioactive ions. The singly charged radioactive ions, produced in an isotope separator on-line facility, and extracted with a low kinetic energy of some tens of keV, are injected into a charge breeder, where the charge state is increased to Q. The transformed ions are either directed towards a dedicated experiment requiring highly charged ions, or post-accelerated to higher beam energies. In this paper the physics processes involved in the production of highly charged ions will be introduced, and the injection and extraction beam parameters of the charge breeder defined. A description of the three main charge-breeding methods is given, namely: electron stripping in gas jet or foil; external ion injection into an electron-beam ion source/trap (EBIS/T); and external ion injection into an electron cyclotron resonance ion source (ECRIS). In addition, some preparatory devices for charge breeding and practical beam delivery aspects ...

  13. Pions from and about heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, J.O.

    1982-09-01

    A review is presented of the possibilities of pion production with heavy ion reactions. Major headings include: pion thermometry; hills and valleys in pion spectra; pionic orbits of nuclear size; pion confinement in the fireball; anomalons; and Schroedinger equation solutions for pionic atoms. 47 references, 9 figures. (GHT)

  14. Monitoring objects orbiting earth using satellite-based telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Olivier, Scot S.; Pertica, Alexander J.; Riot, Vincent J.; De Vries, Willem H.; Bauman, Brian J.; Nikolaev, Sergei; Henderson, John R.; Phillion, Donald W.

    2015-06-30

    An ephemeris refinement system includes satellites with imaging devices in earth orbit to make observations of space-based objects ("target objects") and a ground-based controller that controls the scheduling of the satellites to make the observations of the target objects and refines orbital models of the target objects. The ground-based controller determines when the target objects of interest will be near enough to a satellite for that satellite to collect an image of the target object based on an initial orbital model for the target objects. The ground-based controller directs the schedules to be uploaded to the satellites, and the satellites make observations as scheduled and download the observations to the ground-based controller. The ground-based controller then refines the initial orbital models of the target objects based on the locations of the target objects that are derived from the observations.

  15. Spin–orbit coupling in actinide cations

    DEFF Research Database (Denmark)

    Bagus, Paul S.; Ilton, Eugene S.; Martin, Richard L.

    2012-01-01

    The limiting case of Russell–Saunders coupling, which leads to a maximum spin alignment for the open shell electrons, usually explains the properties of high spin ionic crystals with transition metals. For actinide compounds, the spin–orbit splitting is large enough to cause a significantly reduced...... spin alignment. Novel concepts are used to explain the dependence of the spin alignment on the 5f shell occupation. We present evidence that the XPS of ionic actinide materials may provide direct information about the angular momentum coupling within the 5f shell....

  16. Elasticity, viscosity, and deformation of orbital fat

    OpenAIRE

    Schoemaker, Ivo; Hoefnagel, Pepijn; Mastenbroek, Tom; Kolff, Cornelis; Schutte, Sander; Helm, Frans; Picken, Stephen; Gerritsen, Anton; Wielopolski, Piotr; Spekreijse, Henk; Simonsz, Huib

    2006-01-01

    textabstractPURPOSE. For development of a finite element analysis model of orbital mechanics, it was necessary to determine the material properties of orbital fat and its degree of deformation in eye rotation. METHODS. Elasticity and viscosity of orbital fat of eight orbits of four calves and two orbits of one rhesus monkey were measured with a parallel-plate rheometer. The degree of deformation of orbital fat was studied in two human subjects by magnetic resonance imaging (MRI) through the o...

  17. Orbit-to-ground Wireless Power Transfer test mission

    Science.gov (United States)

    Bergsrud, C.; Noghanian, S.; Straub, J.; Whalen, D.; Fevig, R.

    Since the 1970s the concept of transferring power from orbit for use on Earth has had a great deal of consideration for future energy and environmental sustainability here on Earth. The cost, size and complexity of a production-grade system are extremely large, and have many environmental considerations. There has never been a publicly disclosed orbit-to-ground power transfer test mission. A proposed project provides an opportunity to test the conceptual operation of such a system, albeit at a much lower power level than the `grand' or `real scale' system. During this test, a small Solar Powered (SP) 6-U CubSat will be deployed into Low-Earth Orbit (LEO) (225 or 325 km) to collect and store 1 KW of power from solar energy as the satellite is orbiting. The goal is to transmit 1 KW of wireless power at a microwave frequency of 5.8 or 10 GHz to a ground antenna array system. This paper presents the architecture for the proposed mission and discusses the regulatory, legal, and environmental issues that such a mission poses. Furthermore, the gain of the transmitter is analyzed at 20 and 30 dB as well as the gain of the receiver is analyzed at 30, 40, and 50 dB. A SP 6-U CubeSat will have a Lithium Ion (LIon) battery capable of storing enough energy for 83.33 Whr charge to run the satellites controls, and 1 KW necessary for a 5-minute demonstration and test (in addition to power required for its own operational requirements). Once charged, the satellite will use highly accurate position and attitude knowledge provided by an onboard star-tracker, Global Positioning Satellite (GPS) and inertial measurement unit to determine the proper orientation for the power transfer test. The onboard Attitude Determination and Control (ADCS) will be utilized to achieve and maintain this orientation during the test period. A cold-gas propulsion system will be available to de-spin the reaction wheels to ensure that sufficient ADCS capabilities exist for attitude-stabilization use during

  18. Sodium Ion Dynamics in the Magnetospheric Flanks of Mercury

    Science.gov (United States)

    Aizawa, Sae; Delcourt, Dominique; Terada, Naoki

    2018-01-01

    We investigate the transport of planetary ions in the magnetospheric flanks of Mercury. In situ measurements from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft show evidences of Kelvin-Helmholtz instability development in this region of space, due to the velocity shear between the downtail streaming flow of solar wind originating protons in the magnetosheath and the magnetospheric populations. Ions that originate from the planet exosphere and that gain access to this region of space may be transported across the magnetopause along meandering orbits. We examine this transport using single-particle trajectory calculations in model Magnetohydrodynamics simulations of the Kelvin-Helmholtz instability. We show that heavy ions of planetary origin such as Na+ may experience prominent nonadiabatic energization as they E × B drift across large-scale rolled up vortices. This energization is controlled by the characteristics of the electric field burst encountered along the particle path, the net energy change realized corresponding to the maximum E × B drift energy. This nonadiabatic energization also is responsible for prominent scattering of the particles toward the direction perpendicular to the magnetic field.

  19. Magnetism in Ca 2 CoOsO 6 and Ca 2 NiOsO 6 : Unraveling the Mystery of Superexchange Interactions between 3d and 5d Ions

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, Ryan; Samanta, Kartik; Saha Dasgupta, Tanusri; Xiong, Jie; Freeland, John W.; Haskel, Daniel; Woodward, Patrick M.

    2016-06-14

    In order to rationalize and predict the behavior of compounds containing 5d transition metal ions, an understanding of the local moments and superexchange interactions from which their magnetic properties are derived is necessary. The magnetic and electrical properties of the ferrimagnetic double perovskites Ca2CoOsO6 and Ca2NiOsO6 studied here provide critical insight toward that goal. First-principles density functional theory (DFT) calculations indicate, and experimental measurements confirm, that the Os(VI) moments are directed antiparallel to the Co/Ni moments. X-ray magnetic circular dichroism (XMCD) measurements reveal that the orbital moment on osmium has a magnitude that is approximately 30% of the spin moment, and the two contributions oppose each other. Both the size and direction of the orbital moment are confirmed by the DFT calculations. The size of the Os(VI) total moment is predicted to be 0.6-0.7 μB by DFT calculations. The ferrimagnetic ground state is stabilized by strong antiferromagnetic coupling between the d2 Os(VI) ion and the d8/d7 Ni(II)/Co(II) ion. Not only does the observation of antiferromagnetic coupling violate the Goodenough-Kanamori rules, but also it is unusual in that it becomes stronger as the Os-O-Co/Ni bond angle decreases. This unusual behavior is shown to arise predominantly from coupling between Os t2g orbitals and Ni/Co eg orbitals, mediated by the intervening oxide ion. We further find that both compounds are spin-orbit assisted Mott insulators.

  20. Management of odontogenic orbital cellulitis.

    Science.gov (United States)

    DeCroos, F C; Liao, J C; Ramey, N A; Li, I

    2011-08-15

    This work describes a series of patients with odontogenic orbital cellulitis (OOC), focusing on rate of abscess formation, need for surgical intervention, and imaging findings helpful for rapid diagnosis. Review of a current case and 22 patients with OOC from the scientific literature demonstrated periapical lucency as the most commonly (36.4%) reported finding on facial and orbital computerized tomography (CT) scan. Orbital abscess occurred in 72.7% of cases, and tooth extraction and/or abscess drainage was required in 95.5% of cases reviewed for control of infection. The current case presented with periapical lucency on CT scan, developed orbital abscess despite broad spectrum antibiotic therapy, and required multiple surgical interventions for disease resolution. Though our patient regained excellent vision, OOC often can result in severe vision loss. Periapical lucency on CT can help identify this atypical origin of cellulitis that is strongly associated with abscess formation and need for surgical intervention.

  1. Real and Hybrid Atomic Orbitals.

    Science.gov (United States)

    Cook, D. B.; Fowler, P. W.

    1981-01-01

    Demonstrates that the Schrodinger equation for the hydrogenlike atom separates in both spheroconal and prolate spheroidal coordinates and that these separations provide a sound theoretical basis for the real and hybrid atomic orbitals. (Author/SK)

  2. Lidar Orbital Angular Momentum Sensor

    Data.gov (United States)

    National Aeronautics and Space Administration — The recognition in recent decades that electromagnetic fields have angular momentum (AM) in the form of not only polarization (or spin AM) but also orbital (OAM) has...

  3. A Case of Orbital Histoplasmosis.

    Science.gov (United States)

    Krakauer, Mark; Prendes, Mark Armando; Wilkes, Byron; Lee, Hui Bae Harold; Fraig, Mostafa; Nunery, William R

    2016-01-01

    Histoplasma capsulatum var capsulatum is a dimorphic fungus endemic to the Ohio and Mississippi River Valleys of the United States. In this case report, a 33-year-old woman who presented with a right orbital mass causing progressive vision loss, diplopia, and facial swelling is described. Lateral orbitotomy with lateral orbital wall bone flap was performed for excisional biopsy of the lesion. The 1.5 × 1.8 × 2.3 cm cicatricial mass demonstrated a granulomatous lesion with necrosis and positive staining consistent with Histoplasma capsulatum var capsulatum infection. To the authors' knowledge, this is the first case of orbital histoplasmosis to be reported in the United States and the first case worldwide of orbital histoplasmosis due to Histoplasma capsulatum var capsulatum.

  4. Impact Effects Calculator. Orbital Parameters.

    Science.gov (United States)

    Glazachev, D.; Naroenkov, S.; Kartashova, A.; Turuntaev, I.; Svetsov, V.; Shuvalov, V.; Popova, O.; Podobnaya, E.

    2017-09-01

    Next-generation Impact Calculator for quick assessment of impact consequences is preparing. The estimates of impact effects are revised. The possibility to manipulate with the orbital parameters and to determine impact point is included.

  5. High Power Orbit Transfer Vehicle

    National Research Council Canada - National Science Library

    Gulczinski, Frank

    2003-01-01

    ... from Virginia Tech University and Aerophysics, Inc. to examine propulsion requirements for a high-power orbit transfer vehicle using thin-film voltaic solar array technologies under development by the Space Vehicles Directorate (dubbed PowerSail...

  6. Soft x-ray resonant diffraction study of magnetic and orbital correlations in a manganite near half doping

    NARCIS (Netherlands)

    Thomas, KJ; Grenier, S; Kim, YJ; Abbamonte, P; Rusydi, A; Tomioka, Y; Tokura, Y; McMorrow, DF; Sawatzky, G; van Veenendaal, M; Hill, J.P.; Venema, L.C.

    2004-01-01

    We have utilized resonant x-ray diffraction at the Mn L(II,III) edges in order to directly compare magnetic and orbital correlations in Pr(0.6)Ca(0.4)MnO(3). Comparing the widths of the magnetic and orbital diffraction peaks, we find that the magnetic correlation length exceeds that of the orbital

  7. Topological imprint for periodic orbits

    International Nuclear Information System (INIS)

    Martín, Jesús San; Moscoso, Ma José; Gómez, A González

    2012-01-01

    The more self-crossing points an orbit has the more complex it is. We introduce the topological imprint to characterize crossing points and focus on the period-doubling cascade. The period-doubling cascade topological imprint determines the topological imprint for orbits in chaotic bands. In addition, there is a closer link between this concept and the braids studied by Lettelier et al (2000 J. Phys. A: Math. Gen. 33 1809–25). (paper)

  8. GridOrbit public display

    DEFF Research Database (Denmark)

    Ramos, Juan David Hincapie; Tabard, Aurélien; Bardram, Jakob

    2010-01-01

    We introduce GridOrbit, a public awareness display that visualizes the activity of a community grid used in a biology laboratory. This community grid executes bioin-formatics algorithms and relies on users to donate CPU cycles to the grid. The goal of GridOrbit is to create a shared awareness about...... people comment on projects. Our work explores the usage of interactive technologies as enablers for the appropriation of an otherwise invisible infrastructure....

  9. Accurate ab initio potential for HO2+ : CBS extrapolated energies and direct-fit diatomic curves

    Science.gov (United States)

    Xavier, F. George D.; Martínez-González, Marco; Varandas, A. J. C.

    2018-01-01

    A potential energy surface is reported at the complete basis set limit for the ground electronic state of HO2+ via a four dimensional interpolation in relaxed hyperspherical coordinates. The dissociated products OH+ and O2+ have also been studied at the complete basis set level and subsequently analytically modelled. In the case of O2+, the vibrational states predicted from the model potential have also been directly included in the fit. The potential form so obtained matches the RKR levels with a root mean square deviation below 1cm-1 . Spin orbit + relativistic effects have also been taken into account for the O2+ ion.

  10. Orbital motions as gradiometers for post-Newtonian tidal effects

    Directory of Open Access Journals (Sweden)

    Lorenzo eIorio

    2014-08-01

    Full Text Available The direct long-term changes occurring in the orbital dynamics of a local gravitationally bound binary system S due to the post-Newtonian tidal acceleration caused by an external massive source are investigated. A class of systems made of a test particle m rapidly orbiting with orbital frequency nb an astronomical body of mass M which, in turn, slowly revolves around a distantobject of mass M with orbital frequency nb'<< □ nb is considered. The characteristic frequenciesof the non-Keplerian orbital variations of m and of M itself are assumed to be negligible withrespect to both nb and nb'. General expressions for the resulting Newtonian and post-Newtoniantidal orbital shifts of m are obtained. The future missions BepiColombo and JUICE to Mercuryand Ganymede, respectively, are considered in view of a possible detection. The largest effects,of the order of □ 0:1 □□ 0:5 milliarcseconds per year (mas yr□□1, occur for the Ganymede orbiterof the JUICE mission. Although future improvements in spacecraft tracking and orbit determina14tion might, perhaps, reach the required sensitivity, the systematic bias represented by the otherknown orbital perturbations of both Newtonian and post-Newtonian origin would be overwhel16ming. The realization of a dedicated artificial mini-planetary system to be carried onboard andEarth-orbiting spacecraft is considered as well. Post-Newtonian tidal precessions as large as1 □□ 102 mas yr□□1 could be obtained, but the quite larger Newtonian tidal effects would be amajor source of systematic bias because of the present-day percent uncertainty in the product of the Earth’s mass times the Newtonian gravitational parameter.

  11. Medium-energy ion reflection from solids

    CERN Document Server

    Mashkova, ES

    1985-01-01

    ``Medium-Energy Ion Reflection from Solids'' analyses the results of experimental, theoretical and computer investigations on the process of scattering of ions by solid surfaces. Surface scattering is a relatively young and rapidly developing branch of the physics of atomic collisions and the literature on this subject has rapidly grown.As the first monograph devoted specifically to surface scattering of ions, this book is directed at scientists involved in ion-solid interaction studies.

  12. The ion experiment onboard the Interball-Aurora satellite; initial results on velocity-dispersed structures in the cleft and inside the auroral oval

    Directory of Open Access Journals (Sweden)

    J. A. Sauvaud

    1998-09-01

    Full Text Available The Toulouse ION experiment flown on the Russian Interball-Aurora mission performs simultaneous ion and electron measurements. Two mass spectrometers looking in opposing directions perpendicular to the satellite spin axis, which points toward the sun, measure ions in the mass and energy ranges 1–32 amu and ~0–14 000 eV. Two electron spectrometers also looking in opposing directions perform measurements in the energy range ~10 eV–20 000 eV. The Interball-Aurora spacecraft was launched on 29 August 1996 into a 62.8° inclination orbit with an apogee of ~3 RE. The satellite orbital period is 6 h, so that every four orbits the satellite sweeps about the same region of the auroral zone; the orbit plane drifts around the pole in ~9 months. We present a description of the ION experiment and discuss initial measurements performed in the cusp near noon, in the polar cleft at dusk, and inside the proton aurora at dawn. Ion-dispersed energy structures resulting from time-of-flight effects are observed both in the polar cleft at ~16 hours MLT and in the dawnside proton aurora close to 06 hours MLT. Magnetosheath plasma injections in the polar cleft, which appear as overlapping energy bands in particle energy-time spectrograms, are traced backwards in time using a particle trajectory model using 3D electric and magnetic field models. We found that the cleft ion source is located at distances of the order of 18 RE from the earth at about 19 MLT, i.e., on the flank of the magnetopause. These observations are in agreement with flux transfer events (FTE occurring not only on the front part of the magnetopause but also in a region extending at least to dusk. We also show that, during quiet magnetic conditions, time-of-flight ion dispersions can also be measured inside the dawn proton aurora. A method similar to that used for the cleft is applied to these auroral energy dispersion signatures. Unexpectedly, the ion source is found to be at distances of the

  13. The ion experiment onboard the Interball-Aurora satellite; initial results on velocity-dispersed structures in the cleft and inside the auroral oval

    Directory of Open Access Journals (Sweden)

    J. A. Sauvaud

    Full Text Available The Toulouse ION experiment flown on the Russian Interball-Aurora mission performs simultaneous ion and electron measurements. Two mass spectrometers looking in opposing directions perpendicular to the satellite spin axis, which points toward the sun, measure ions in the mass and energy ranges 1–32 amu and ~0–14 000 eV. Two electron spectrometers also looking in opposing directions perform measurements in the energy range ~10 eV–20 000 eV. The Interball-Aurora spacecraft was launched on 29 August 1996 into a 62.8° inclination orbit with an apogee of ~3 RE. The satellite orbital period is 6 h, so that every four orbits the satellite sweeps about the same region of the auroral zone; the orbit plane drifts around the pole in ~9 months. We present a description of the ION experiment and discuss initial measurements performed in the cusp near noon, in the polar cleft at dusk, and inside the proton aurora at dawn. Ion-dispersed energy structures resulting from time-of-flight effects are observed both in the polar cleft at ~16 hours MLT and in the dawnside proton aurora close to 06 hours MLT. Magnetosheath plasma injections in the polar cleft, which appear as overlapping energy bands in particle energy-time spectrograms, are traced backwards in time using a particle trajectory model using 3D electric and magnetic field models. We found that the cleft ion source is located at distances of the order of 18 RE from the earth at about 19 MLT, i.e., on the flank of the magnetopause. These observations are in agreement with flux transfer events (FTE occurring not only on the front part of the magnetopause but also in a region extending at least to dusk. We also show that, during quiet magnetic conditions, time-of-flight ion dispersions can also be measured inside the dawn proton aurora. A method similar to that used for the cleft is applied to these auroral energy dispersion signatures. Unexpectedly, the ion source is found to be

  14. Calculation of Auger-neutralization probabilities for He{sup +}-ions in LEIS

    Energy Technology Data Exchange (ETDEWEB)

    Goebl, D., E-mail: dominik.goebl@jku.at [Institut Fuer Experimentalphysik, Abt. Atom- und Oberflaechenphysik, Johannes Kepler Universitaet, A-4040 Linz (Austria); Monreal, R.C.; Valdes, D.; Primetzhofer, D. [Departamento de Fisica Teorica de la Materia Condensada, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Bauer, P. [Institut Fuer Experimentalphysik, Abt. Atom- und Oberflaechenphysik, Johannes Kepler Universitaet, A-4040 Linz (Austria)

    2011-06-01

    In Low Energy Ion Scattering (LEIS), Auger-neutralization is an omnipresent charge exchange mechanism, especially when noble gas ions are used as projectiles, with a primary energy below the threshold energy, E{sub th}, for collision induced charge exchange processes (neutralization and reionization). Recent experiments revealed a significant dependence of the ion survival probability, P{sup +}, on the crystal plane, when He{sup +} ions are scattered from a metal surface. This is in contrast to the fact, that the neutralization probability in LEIS is usually assumed to be independent of the chemical environment of the collision partner (absence of matrix effects). In order to investigate this crystal effect, an existent theory on Auger-neutralization (based on a Linear Combination of Atomic Orbitals) is adapted to the LEIS geometry. With this model, Auger-neutralization rates are calculated for a Ag(1 1 0) surface. Trajectories for He particles scattered from this surface into different azimuth directions are obtained by means of Molecular Dynamics simulations. Subsequently, the ion survival probability is calculated and compared to measurements. Good agreement is obtained which gives confidence in the applicability of this model in the LEIS regime. Moreover, it was possible to obtain detailed information on the properties of the neutralization process.

  15. RKKY interaction between Ce ions in CexLa1-xB6

    International Nuclear Information System (INIS)

    Schlottmann, P.

    2000-01-01

    Ce ions in (Ce x La 1-x )B 6 have a Γ 8 ground multiplet, which is fourfold degenerate and has orbital and spin content. The interaction between Ce ions is of the Ruderman-Kittel-Kasuya-Yosida (RKKY) type, which competes with the Kondo screening. The conduction states of the compound are described by three approximately ellipsoidal pockets centered at the X points of the cubic lattice. The RKKY interaction is calculated considering the interference of the three pockets. The interaction strength strongly depends on the relative position of the ions, as well as on the relative orientation of the line joining two ions to the cubic crystalline field axis. The sixteen states of a pair of Ce ions are split by the RKKY interaction into a singlet, a triplet, and a twelvefold degenerate level. The ground state is always either a singlet or a triplet, depending on the sign of the interaction. Using the exact Bethe ansatz solution of a model for a pair of interacting impurities with Γ 8 ground multiplet, we calculate the occupation of the levels, the magnetic-field susceptibility, the specific-heat γ coefficient, and the Wilson ratio for the ground state as a function of the ratio of the RKKY coupling strength to the Kondo temperature along the main crystallographic directions. As a consequence of the RKKY splitting a pair of impurities always has a quadrupolar moment. The implication of the interactions on the quadrupolar order of CeB 6 is also discussed

  16. Power consumption in positive ion beam converter with electrostatic electron suppressor

    International Nuclear Information System (INIS)

    Hashimoto, Kiyoshi; Sugawara, Tohru

    1985-01-01

    The power recovery characteristics of an in-line direct beam converter provided with electrostatic electron suppressor were studied numerically by tracing the orbits of fast primary ions and secondary charged particles generated along their beam path by collision with background gas molecules. It is shown that, in reference to the electrostatic field potential at the point of impact, the energy distribution of secondary ions impinging on the suppressor has two peaks-one corresponding to a zone of high positive potential surrounding the collector and the other to one of slightly negative potential around the electron suppressor. Secondary electron emission from the suppressor is ascribed mainly to the latter peak, associated with impingement of slower secondary ions. Far much power consumed in secondary particle acceleration is spent for emitting electrons from the suppressor than for secondary ions generated by beam-gas collision. The upper limit of background pressure is discussed on the basis of criteria prescribed for restricting the power consumed in this secondary particle acceleration, as for practical convenience of electrode cooling. Numerical examples are given of calculations based on particle trajectory analysis of both primary ions and secondary particles, for the case of a 100 keV-proton sheet beam 10 cm thick of 35 mA/cm 2 current density. (author)

  17. International Space Station Lithium-Ion Battery

    Science.gov (United States)

    Dalton, Penni J.; Schwanbeck, Eugene; North, Tim; Balcer, Sonia

    2016-01-01

    The International Space Station (ISS) primary Electric Power System (EPS) currently uses Nickel-Hydrogen (Ni-H2) batteries to store electrical energy. The electricity for the space station is generated by its solar arrays, which charge batteries during insolation for subsequent discharge during eclipse. The Ni-H2 batteries are designed to operate at a 35 depth of discharge (DOD) maximum during normal operation in a Low Earth Orbit. Since the oldest of the 48 Ni-H2 battery Orbital Replacement Units (ORUs) has been cycling since September 2006, these batteries are now approaching their end of useful life. In 2010, the ISS Program began the development of Lithium-Ion (Li-Ion) batteries to replace the Ni-H2 batteries and concurrently funded a Li-Ion ORU and cell life testing project. When deployed, they will be the largest Li-Ion batteries ever utilized for a human-rated spacecraft. This paper will include an overview of the ISS Li-Ion battery system architecture, the Li-Ion battery design and development, controls to limit potential hazards from the batteries, and the status of the Li-Ion cell and ORU life cycle testing.

  18. Multidirectional Cosmic Ray Ion Detector for Deep Space CubeSats

    Science.gov (United States)

    Wrbanek, John D.; Wrbanek, Susan Y.

    2016-01-01

    Understanding the nature of anisotropy of solar energetic protons (SEPs) and galactic cosmic ray (GCR) fluxes in the interplanetary medium is crucial in characterizing time-dependent radiation exposure in interplanetary space for future exploration missions. NASA Glenn Research Center has proposed a CubeSat-based instrument to study solar and cosmic ray ions in lunar orbit or deep space. The objective of Solar Proton Anisotropy and Galactic cosmic ray High Energy Transport Instrument (SPAGHETI) is to provide multi-directional ion data to further understand anisotropies in SEP and GCR flux. The instrument is to be developed using large area detectors fabricated from high density, high purity silicon carbide (SiC) to measure linear energy transfer (LET) of ions. Stacks of these LET detectors are arranged in a CubeSat at orthogonal directions to provide multidirectional measurements. The low-noise, thermally-stable nature of silicon carbide and its radiation tolerance allows the multidirectional array of detector stacks to be packed in a 6U CubeSat without active cooling. A concept involving additional coincidence/anticoincidence detectors and a high energy Cherenkov detector is possible to further expand ion energy range and sensitivity.

  19. A case of acute orbital myositis which was difficult to diagnose at first

    International Nuclear Information System (INIS)

    Yamamoto, Kiyoshi; Terabayashi, Tadasu; Mori, Hiroshi; Niida, Hirohito; Sugiyama, Yoshiaki; Nakagawa, Masato

    1988-01-01

    We report a case of acute orbital myositis. A 61-year-old woman exhibited acute orbital pain, diplopia, and left proptosis. Examination revealed a 5-mm left proptosis, left chemosis, and limitations in all directions of the movement of the left eye. Visual acuity was unimpaired, however, and the neurological examination was otherwise normal. CT demonstrated a left inferior orbital mass. We suspected an acute orbital pseudotumor based on the rapid onset and the clinical symptoms. We treated her with systemic corticosteroids. Four weeks later CT documented a reduced left orbital mass; there seemed to be left only an inferior rectus muscle enlargement. We diagnosed acute orbital myositis, a subgroup of orbital pseudotumors, based upon the rapid clinical presentation, the CT features, and the resolution after treatment with systemic corticosteroids. (author)

  20. A novel planar ion funnel design for miniature ion optics

    International Nuclear Information System (INIS)

    Chaudhary, A.; Amerom, Friso H. W. van; Short, R. T.

    2014-01-01

    The novel planar ion funnel (PIF) design presented in this article emphasizes simple fabrication, assembly, and operation, making it amenable to extreme miniaturization. Simulations performed in SIMION 8.0 indicate that ion focusing can be achieved by using a gradient of electrostatic potentials on concentric metal rings in a plane. A prototype was fabricated on a 35 × 35 mm custom-designed printed circuit board (PCB) with a center hole for ions to pass through and a series of concentric circular metal rings of increasing diameter on the front side of the PCB. Metal vias on the PCB electrically connected each metal ring to a resistive potential divider that was soldered on the back of the PCB. The PIF was tested at 5.5 × 10 −6 Torr in a vacuum test setup that was equipped with a broad-beam ion source on the front and a micro channel plate (MCP) ion detector on the back of the PIF. The ion current recorded on the MCP anode during testing indicated a 23× increase in the ion transmission through the PIF when electric potentials were applied to the rings. These preliminary results demonstrate the functionality of a 2D ion funnel design with a much smaller footprint and simpler driving electronics than conventional 3D ion funnels. Future directions to improve the design and a possible micromachining approach to fabrication are discussed in the conclusions