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Sample records for large atomic displacement

  1. Large displacement spherical joint

    DOEpatents

    Bieg, Lothar F.; Benavides, Gilbert L.

    2002-01-01

    A new class of spherical joints has a very large accessible full cone angle, a property which is beneficial for a wide range of applications. Despite the large cone angles, these joints move freely without singularities.

  2. Atomic displacements in ferroelectric trigonal and orthorhombic boracite structures

    USGS Publications Warehouse

    Dowty, Eric; Clark, J.R.

    1972-01-01

    New crystal-structure refinements of Pca21 boracite, Mg3ClB7O13, and R??{lunate}c ericaite, Fe2.4Mg0.6ClB7O13, show that some boron and oxygen atoms are involved in the 'ferro' transitions as well as the metal and halogen atoms. The atomic displacements associated with the polarity changes are as large as 0.6A??. ?? 1972.

  3. Frictional behavior of large displacement experimental faults

    USGS Publications Warehouse

    Beeler, N.M.; Tullis, T.E.; Blanpied, M.L.; Weeks, J.D.

    1996-01-01

    The coefficient of friction and velocity dependence of friction of initially bare surfaces and 1-mm-thick simulated fault gouges (400 mm at 25??C and 25 MPa normal stress. Steady state negative friction velocity dependence and a steady state fault zone microstructure are achieved after ???18 mm displacement, and an approximately constant strength is reached after a few tens of millimeters of sliding on initially bare surfaces. Simulated fault gouges show a large but systematic variation of friction, velocity dependence of friction, dilatancy, and degree of localization with displacement. At short displacement (<10 mm), simulated gouge is strong, velocity strengthening and changes in sliding velocity are accompanied by relatively large changes in dilatancy rate. With continued displacement, simulated gouges become progressively weaker and less velocity strengthening, the velocity dependence of dilatancy rate decreases, and deformation becomes localized into a narrow basal shear which at its most localized is observed to be velocity weakening. With subsequent displacement, the fault restrengthens, returns to velocity strengthening, or to velocity neutral, the velocity dependence of dilatancy rate becomes larger, and deformation becomes distributed. Correlation of friction, velocity dependence of friction and of dilatancy rate, and degree of localization at all displacements in simulated gouge suggest that all quantities are interrelated. The observations do not distinguish the independent variables but suggest that the degree of localization is controlled by the fault strength, not by the friction velocity dependence. The friction velocity dependence and velocity dependence of dilatancy rate can be used as qualitative measures of the degree of localization in simulated gouge, in agreement with previous studies. Theory equating the friction velocity dependence of simulated gouge to the sum of the friction velocity dependence of bare surfaces and the velocity

  4. Displacement per Atom, Primary Knocked-on Atoms Produced in an Atomic Solid Target

    Energy Science and Technology Software Center (ESTSC)

    2015-07-01

    Version 00 DART calculates the total number of displacements, primary knocked-on atoms, recoil spectra, displacement cross sections and displacement per atoms rates in a poly atomic solid target, composed of many different isotopes, using ENDF/B-VI derived cross sections. To calculate these values, different incident particles were considered: neutrons, ions and electrons. The user needs only to specify an incident particle energy spectrum and the composition of the target. The number of displaced atoms is calculatedmore » within the Binary Collision Approximation framework. To calculate the number of displacements the DART code does not use the classical NRT dpa analytical formula, which is only appropriate for projectile and target of the same mass. It numerically solves the linearized Boltzmann equation for a polyatomic target. It can be a useful tool to select the nature and energy of ions or electrons in particle accelerators or electron microscopes to mimic the primary damage induced by neutron irradiation in nuclear plants or fission facilities. Nuclear data: • Typically any ENDFB format evaluation may be used. This package includes the ENDFB-VI nuclear data library. Energy ranges: • Neutron or ion : 10E-11 to 20 MeV Data library distributed with DART v1.0: • ENDFB-VI nuclear data library« less

  5. Displacement per Atom, Primary Knocked-on Atoms Produced in an Atomic Solid Target

    SciTech Connect

    2015-07-01

    Version 00 DART calculates the total number of displacements, primary knocked-on atoms, recoil spectra, displacement cross sections and displacement per atoms rates in a poly atomic solid target, composed of many different isotopes, using ENDF/B-VI derived cross sections. To calculate these values, different incident particles were considered: neutrons, ions and electrons. The user needs only to specify an incident particle energy spectrum and the composition of the target. The number of displaced atoms is calculated within the Binary Collision Approximation framework. To calculate the number of displacements the DART code does not use the classical NRT dpa analytical formula, which is only appropriate for projectile and target of the same mass. It numerically solves the linearized Boltzmann equation for a polyatomic target. It can be a useful tool to select the nature and energy of ions or electrons in particle accelerators or electron microscopes to mimic the primary damage induced by neutron irradiation in nuclear plants or fission facilities. Nuclear data: • Typically any ENDFB format evaluation may be used. This package includes the ENDFB-VI nuclear data library. Energy ranges: • Neutron or ion : 10E-11 to 20 MeV Data library distributed with DART v1.0: • ENDFB-VI nuclear data library

  6. Atom interferometry using wave packets with constant spatial displacements

    SciTech Connect

    Su, Edward J.; Prentiss, Mara G.; Wu Saijun

    2010-04-15

    A standing-wave light-pulse sequence is demonstrated that places atoms into a superposition of wave packets with precisely controlled displacements that remain constant for times as long as 1 s. The separated wave packets are subsequently recombined, resulting in atom interference patterns that probe energy differences of {approx_equal}10{sup -34} J and can provide acceleration measurements that are insensitive to platform vibrations.

  7. Displacement and deformation measurement for large structures by camera network

    NASA Astrophysics Data System (ADS)

    Shang, Yang; Yu, Qifeng; Yang, Zhen; Xu, Zhiqiang; Zhang, Xiaohu

    2014-03-01

    A displacement and deformation measurement method for large structures by a series-parallel connection camera network is presented. By taking the dynamic monitoring of a large-scale crane in lifting operation as an example, a series-parallel connection camera network is designed, and the displacement and deformation measurement method by using this series-parallel connection camera network is studied. The movement range of the crane body is small, and that of the crane arm is large. The displacement of the crane body, the displacement of the crane arm relative to the body and the deformation of the arm are measured. Compared with a pure series or parallel connection camera network, the designed series-parallel connection camera network can be used to measure not only the movement and displacement of a large structure but also the relative movement and deformation of some interesting parts of the large structure by a relatively simple optical measurement system.

  8. On the Origin of Large Interstitial Clusters in Displacement Cascades

    SciTech Connect

    Andrew, Calder F; Barashev, Aleksandr; Bacon, David J; Osetskiy, Yury N

    2010-01-01

    Displacement cascades with wide ranges of primary knock-on atom (PKA) energy and mass in iron were simulated using molecular dynamics. New visualisation techniques are introduced to show how the shock-front dynamics and internal structure of a cascade develop over time. These reveal that the nature of the final damage is determined early on in the cascade process. We define a zone (termed 'spaghetti') in which atoms are moved to new lattice sites and show how it is created by a supersonic shock-front expanding from the primary recoil event. A large cluster of self-interstitial atoms can form on the periphery of the spaghetti if a hypersonic recoil creates damage with a supersonic shock ahead of the main supersonic front. When the two fronts meet, the main one injects atoms into the low-density core of the other: these become interstitial atoms during the rapid recovery of the surrounding crystal. The hypersonic recoil occurs in less than 0.1 ps after the primary recoil and the interstitial cluster is formed before the onset of the thermal spike phase of the cascade process. The corresponding number of vacancies is then formed in the spaghetti core as the crystal cools, i.e. at times one to two orders of magnitude longer. By using the spaghetti zone to define cascade volume, the energy density of a cascade is shown to be almost independent of the PKA mass. This throws into doubt the conventional energy-density interpretation of an increased defect yield with increasing PKA mass in ion irradiation.

  9. On the origin of large interstitial clusters in displacement cascades

    NASA Astrophysics Data System (ADS)

    Calder, A. F.; Bacon, D. J.; Barashev, A. V.; Osetsky, Yu. N.

    2010-03-01

    Displacement cascades with wide ranges of primary knock-on atom (PKA) energy and mass in iron were simulated using molecular dynamics. New visualisation techniques are introduced to show how the shock-front dynamics and internal structure of a cascade develop over time. These reveal that the nature of the final damage is determined early on in the cascade process. We define a zone (termed 'spaghetti') in which atoms are moved to new lattice sites and show how it is created by a supersonic shock-front expanding from the primary recoil event. A large cluster of self-interstitial atoms can form on the periphery of the spaghetti if a hypersonic recoil creates damage with a supersonic shock ahead of the main supersonic front. When the two fronts meet, the main one injects atoms into the low-density core of the other: these become interstitial atoms during the rapid recovery of the surrounding crystal. The hypersonic recoil occurs in less than 0.1 ps after the primary recoil and the interstitial cluster is formed before the onset of the thermal spike phase of the cascade process. The corresponding number of vacancies is then formed in the spaghetti core as the crystal cools, i.e. at times one to two orders of magnitude longer. By using the spaghetti zone to define cascade volume, the energy density of a cascade is shown to be almost independent of the PKA mass. This throws into doubt the conventional energy-density interpretation of an increased defect yield with increasing PKA mass in ion irradiation.

  10. Large displacement vertical translational actuator based on piezoelectric thin films

    PubMed Central

    Qiu, Zhen; Pulskamp, Jeffrey S; Lin, Xianke; Rhee, Choong-Ho; Wang, Thomas; Polcawich, Ronald G; Oldham, Kenn

    2014-01-01

    A novel vertical translational microactuator based on thin-film piezoelectric actuation is presented, using a set of four compound bend-up/bend-down unimorphs to produce translational motion of a moving platform or stage. The actuation material is a chemical-solution deposited lead–zirconate–titanate (PZT) thin film. Prototype designs have shown as much as 120 μm of static displacement, with 80–90 μm displacements being typical, using four 920 μm long by 70 μm legs. Analytical models are presented that accurately describe nonlinear behavior in both static and dynamic operation of prototype stages when the dependence of piezoelectric coefficients on voltage is known. Resonance of the system is observed at a frequency of 200 Hz. The large displacement and high bandwidth of the actuators at low-voltage and low-power levels should make them useful to a variety of optical applications, including endoscopic microscopy. PMID:25506130

  11. Effect of magnetism and atomic order on static atomic displacements in the Invar alloy Fe-27 at.% Pt

    NASA Astrophysics Data System (ADS)

    Sax, C. R.; Schönfeld, B.; Ruban, A. V.

    2015-08-01

    Fe-27 at.% Pt was aged at 1123 K and quenched to room temperature (RT) to set up a state of thermal equilibrium. The local atomic arrangement was studied by diffuse x-ray scattering above (at 427 K) and below (at RT) the Curie temperature as well as at RT under a saturating magnetic field. The separated short-range order scattering remained unchanged for all three states, with maxima at 100 positions. Effective pair interaction parameters determined by the inverse Monte Carlo method gave an order-disorder transition temperature of about 1088 K, close to direct experimental findings. The species-dependent static atomic displacements for the first two shells show large differences, with a strong increase in magnitude from the state at 427 K over RT to the state under saturating magnetic field. This outcome is in agreement with an increase in atomic volume of Fe with increasing local magnetic moment. Electronic-structure calculations closely reproduce the values for the static atomic displacements in the ferromagnetic state, and predict their dependence on the atomic configuration. They also reveal a strong dependence of the magnetic exchange interactions in Fe-Pt on the atomic configuration state and lattice parameter. In particular, the increase of the Curie temperature in a random state relative to that in the ordered one is demonstrated to be related to the corresponding change of the magnetic exchange interactions due to the different local atomic chemical environment. There exists a similar strong concentration dependence of the chemical interactions as in the case of magnetic exchange interactions. Theoretical effective interactions for Fe-27 at.% Pt alloy are in good agreement with experimental results, and they also reproduce well the L1 2-A1 transition temperature.

  12. Disparate atomic displacements in skutterudite-type LaFe3CoSb12, a model for thermoelectric behavior.

    PubMed

    Chakoumakos; Sales; Mandrus; Keppens

    1999-06-01

    Mean-square atomic displacements in lanthanum triiron cobalt dodecaantimonide, determined as a function of temperature using single-crystal neutron diffraction, show that the La atom exhibits an anomalously large displacement at room temperature, U(eq) = 0.0196 (9) Å(2), because it is too small to fill the atomic cage formed by the corner-linked octahedral framework of M(4)Sb(12), M = Fe, Co. Site-occupancy refinements show 25% vacancies on the La site and an actual Fe:Co ratio of 2.17:1. Analysis of the temperature dependence of the atomic displacements identifies a significant temperature-independent component for the La atom ascribed to static disorder, which amounts to 19% of the room-temperature value. The large-amplitude rattling of the La atom can be effectively linked to the dramatic decrease of the lattice contribution to the thermal conductivity, which is a key factor for improving the thermoelectric behavior of these materials. This structure-property relationship offers a new paradigm for the exploration of thermoelectric materials. PMID:10927376

  13. Calculations of dynamical properties of skutterudites: Thermal conductivity, thermal expansivity, and atomic mean-square displacement

    SciTech Connect

    Bernstein, N.; Feldman, J. L.; Singh, David J.

    2010-04-05

    While the thermal conductivity of the filled skutterudites has been of great interest it had not been calculated within a microscopic theory. Here a central force, Guggenheim-McGlashen, model with parameters largely extracted from first-principles calculations and from spectroscopic data, specific to LaFe{sub 4} Sb{sub 12} or CoSb{sub 3} , is employed in a Green-Kubo/molecular dynamics calculation of thermal conductivity as a function of temperature. We find that the thermal conductivity of a filled solid is more than a factor of two lower than that of an unfilled solid, assuming the “framework” interatomic force parameters are the same between filled and unfilled solids, and that this decrease is almost entirely due to the cubic anharmonic interaction between filling and framework atoms. In addition, partially as a test of our models, we calculate thermal expansivity and isotropic atomic mean-square displacements using both molecular dynamics and lattice dynamics methods. These quantities are in reasonable agreement with experiment, increasing our confidence in the anharmonic parameters of our models. We also find an anomalously large filling-atom mode Gruneisen parameter that is apparently observed for a filled skutterudite and is observed in a clathrate.

  14. Impact of Atomic Gap Size on Sensitivity and Backaction of APC Displacement Detectors

    NASA Astrophysics Data System (ADS)

    Flowers-Jacobs, N. E.; Lehnert, K. W.

    2008-03-01

    Recently our group created a mesoscopic displacement detector formed by coupling an atomic point contact (APC) to a nanomechanical beam and demonstrated a displacement imprecision limited by the fundamental shot-noise in the number of electrons that tunnel across the APC [1]. We continue this work by using a cryogenic apparatus that flexes the device substrate to mechanically adjust the size of the APC atomic gap in situ. The resulting changes in the APC displacement detector's intrinsic noise properties are measured by observing the 1 K random thermal motion of the nanomechanical beam at resonance frequencies up to 200 MHz. The goal of this work is to explore the effect of atomic gap size and shape on displacement sensitivity, understand the origin of the observed measurement backaction, and measure the recoil force of tunneling electrons. [1] N. E. Flowers-Jacobs, D. R. Schmidt, and K. W. Lehnert, Phys. Rev. Lett. 98, 096804 (2007)

  15. Atomic structure of cascades of atomic displacements in metals and alloys after different types of radiation

    NASA Astrophysics Data System (ADS)

    Ivchenko, V. A.

    2016-02-01

    Using the methods of field ion microscopy, we studied radiation induced defects on an atomically clean surface and within a subsurface volume of platinum initiated by the interaction of neutron (E > 0.1MeV) and Ar+ beams (E = 30 keV). It is shown that the interaction of fast neutrons (E > 0.1 MeV) F = 6.7-1021 m-2, F = 3.5-1022 m-2 with matter leads to the formation in the amount of platinum such as radiation damage which occur after ion irradiation by beams of charged Ar+ ions with E = 30 keV, F = 1020 ion/m2. They are observed at a depth of about 1.5-2 nm irradiated under the surface of Pt by ions Ar+. Thus, we have carried out modeling of neutron impact with matter when replacing the neutron beam by an ion beam that causes the same radiation damage in the bulk of the material. Experimental results on atomic-spatial investigation of radiative defect formation in surface layers of materials, initiated by neutron bombardment (of Pt, E > 0.1 MeV) and ion implantation (in Cu3Au: E = 40 keV, F = 1020 ion/m2, j = 10-3 A/cm2), are considered. Quantitative estimates obtained for the size, shape, and volume fraction of cascades of atomic displacements formed under various types of irradiation in the surface layers of the materials. It is showing that the average size of radiation clusters after irradiation of platinum to a fast neutron fluence of 6.7-1022 m-2 (E > 0.1 MeV) is about 3.2 nm. The experimentally established average size of a radiation cluster (disordered zone) in the alloy after ion bombardment is 4×4×1.5 nm.

  16. Note: Seesaw actuation of atomic force microscope probes for improved imaging bandwidth and displacement range

    SciTech Connect

    Torun, H.; Torello, D.; Degertekin, F. L.

    2011-08-15

    The authors describe a method of actuation for atomic force microscope (AFM) probes to improve imaging speed and displacement range simultaneously. Unlike conventional piezoelectric tube actuation, the proposed method involves a lever and fulcrum ''seesaw'' like actuation mechanism that uses a small, fast piezoelectric transducer. The lever arm of the seesaw mechanism increases the apparent displacement range by an adjustable gain factor, overcoming the standard tradeoff between imaging speed and displacement range. Experimental characterization of a cantilever holder implementing the method is provided together with comparative line scans obtained with contact mode imaging. An imaging bandwidth of 30 kHz in air with the current setup was demonstrated.

  17. Large spin magnetism with cold atoms

    NASA Astrophysics Data System (ADS)

    Laburthe-Tolra, Bruno

    2016-05-01

    The properties of quantum gases made of ultra-cold atoms strongly depend on the interactions between atoms. These interactions lead to condensed-matter-like collective behavior, so that quantum gases appear to be a new platform to study quantum many-body physics. In this seminar, I will focus on the case where the atoms possess an internal (spin) degrees of freedom. The spin of atoms is naturally larger than that of electrons. Therefore, the study of the magnetic properties of ultra-cold gases allows for an exploration of magnetism beyond the typical situation in solid-state physics where magnetism is associated to the s = 1/2 spin of the electron. I will describe three specific cases: spinor Bose-Einstein condensates, where spin-dependent contact interactions introduce new quantum phases and spin dynamics; large spin magnetic atoms where strong dipole-dipole interactions lead to exotic quantum magnetism; large spin Fermi gases.

  18. Note: Compact and light displacement sensor for a precision measurement system in large motion

    SciTech Connect

    Lee, Sang Heon

    2015-08-15

    We developed a compact and light displacement sensor applicable to systems that require wide range motions of its sensing device. The proposed sensor utilized the optical pickup unit of the optical disk drive, which has been used applied to atomic force microscopy (AFM) because of its compactness and lightness as well as its high performance. We modified the structure of optical pickup unit and made the compact sensor driver attachable to a probe head of AFM to make large rotation. The feasibilities of the developed sensor for a general probe-moving measurement device and for probe-rotating AFM were verified. Moreover, a simple and precise measurement of alignment between centers of rotator and probe tip in probe-rotation AFM was experimentally demonstrated using the developed sensor.

  19. Polar atomic displacements in multiferroics observed via anomalous x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Azimonte, C.; Granado, E.; Terashita, H.; Park, S.; Cheong, S.-W.

    2010-01-01

    The minute polar atomic displacements in multiferroics are shown to be within the reach of crystallography. A nonconventional methodology with anomalous x-ray diffraction is employed to investigate such displacements in DyMn2O5 with giant magnetoelectric coupling and two distinct Mn3+ and Mn4+ sites. Intensity differences of a selected Bragg reflection were measured as the direction of electric polarization is switched by a poling field. A significant differential effect, which is strongly enhanced at energies near and above the MnK edge, was observed near and below the ferroelectric transition temperature, Tc˜40K . The direct participation of ionic displacements in the ferroelectric polarization, particularly the Mn3+ sublattice, is demonstrated, dismissing a purely electronic mechanism for the multiferroicity.

  20. Nanoscale Atomic Displacements Ordering for Enhanced Piezoelectric Properties in Lead-Free ABO3 Ferroelectrics.

    PubMed

    Pramanick, Abhijit; Jørgensen, Mads R V; Diallo, Souleymane O; Christianson, Andrew D; Fernandez-Baca, Jaime A; Hoffmann, Christina; Wang, Xiaoping; Lan, Si; Wang, Xun-Li

    2015-08-01

    In situ synchrotron X-ray diffuse scattering and inelastic neutron scattering measurements from a prototype ABO3 ferroelectric single-crystal are used to elucidate how electric fields along a nonpolar direction can enhance its piezoelectric properties. The central mechanism is found to be a nanoscale ordering of B atom displacements, which induces increased lattice instability and therefore a greater susceptibility to electric-field-induced mechanical deformation. PMID:26076654

  1. Entropy and Entanglement of the Superpositions of Displaced Fock States with a Two-Level Atom

    NASA Astrophysics Data System (ADS)

    Abd Al-Kader, Gamal M.

    The properties of the displaced Fock states (DFS's) superpositions are reviewed. The interaction of these states with a two-level atom in cavity with the presence of additional Kerr medium is studied. Exact general matrix elements of the time-dependent operators of a Jaynes-Cummings model (JCM), in the presence of a Kerr medium, with these states are derived. The atomic inversion and photon number distribution are discussed. The quantum entropy and the entanglement of the atom-field are investigated. The exact results are employed to perform a careful investigation of the temporal evolution of the entropy. The connection between the field entropy and the collapses and revivals of the atomic inversion has been established. The general conclusions reached are illustrated by numerical results.

  2. Spatial Configuration of Atoms with High-Energy Atomic Displacement Cascade in α-Fe

    NASA Astrophysics Data System (ADS)

    Wang, Wei-Lu; Wu, Xuebang; Liu, Wei; Fang, Q. F.; Liu, C. S.; Huang, Qun-Ying; Wu, Y. C.

    2012-11-01

    Molecular dynamics simulations were performed to study the primary damage formation in α-Fe through collision cascades with a cascade energy of up to 100 keV. The pair analysis technique was introduced to characterize the spatial local structure distributions of atoms. The damaged microstructural unit characteristics of the body-centered cubic (bcc) crystal structure, as well as the number of point defects, followed a similar trend. Furthermore, the damaged atoms exist mostly in the microstructural characteristics of icosahedral and short-range ordering in amorphous states during and at the end of cascades. Most local spatial structures of the damaged atoms can be divided into two groups based on their corresponding non-characteristic index-pair change trends with time. The curves of the first group coincided with the vacancy (V) that exhibited one peak, whereas the curves of the second group exhibiting two peaks corresponded to the self-interstitial atoms (SIA). The maximum distance at which defects could interact with each other in space was the fifth nearest-neighbor distance of the atoms of perfect lattices in the bcc lattice. The number of local structural units of the damaged atoms that were connected with a single point defect (either V or SIA) continued to increase with increasing cascade energy by the end of the simulation. By contrast, the number of units that were connected with both V and SIA decreased. These results may help us understand the spatial configuration of atoms in the course of collision cascades.

  3. Ultrahigh-resolution study of protein atomic displacement parameters at cryotemperatures obtained with a helium cryostat.

    PubMed

    Petrova, Tatiana; Ginell, Stephan; Mitschler, Andre; Hazemann, Isabelle; Schneider, Thomas; Cousido, Alexandra; Lunin, Vladimir Y; Joachimiak, Andrzej; Podjarny, Alberto

    2006-12-01

    Two X-ray data sets for a complex of human aldose reductase (h-AR) with the inhibitor IDD 594 and the cofactor NADP(+) were collected from two different parts of the same crystal to a resolution of 0.81 A at 15 and 60 K using cold helium gas as cryogen. The contribution of temperature to the atomic B values was estimated by comparison of the independently refined models. It was found that although being slightly different for different kinds of atoms, the differences (deltaB) in the isotropic equivalents B of atomic displacement parameters (ADPs) were approximately constant (about 1.7 A(2)) for well ordered atoms as the temperature was increased from 15 to 60 K. The mean value of this difference varied according to the number of non-H atoms covalently bound to the parent atom. Atoms having a B value of higher than 8 A(2) at 15 K showed much larger deviations of deltaB from the average value, which might reflect partial occupancy of atomic sites. An analysis of the anisotropy of ADPs for individual atoms revealed an increase in the isotropy of ADPs with the increase of the temperature from 15 to 60 K. In a separate experiment, a 0.93 A resolution data set was collected from a different crystal of the same complex at 100 K using cold nitrogen as a cryogen. The effects of various errors on the atomic B values were estimated by comparison of the refined models and the temperature-dependent component was inferred. It was found that both decreasing the data redundancy and increasing the resolution cutoff led to an approximately constant increase in atomic B values for well ordered atoms. PMID:17139089

  4. Structural optimization of a large-displacement electromagnetic Lorentz force microactuator for optical switching applications

    NASA Astrophysics Data System (ADS)

    Han, Jeong Sam; Ko, Jong Soo; Korvink, Jan G.

    2004-11-01

    This paper discusses optimization of an electromagnetic microactuator for large-displacement optical switching. The microactuator used in this research is a laterally driven electromagnetic one that provides parallel actuation to the silicon substrate surface (in-plane motion) using the Lorentz force. When the microactuator is driven by the distributed Lorentz force induced along the arch-shaped leaf springs, a buckling phenomenon in two leaf springs enables a large displacement with a relatively small actuation load. An important design objective of a microactuator is to achieve a large displacement with a low actuating force. In this research, two optimization formulations have been performed to improve the displacement capabilities of the microactuator. In the first, the actuation load to obtain a specific displacement is minimized, subject to constraints on the first natural frequency and maximum allowable stress. In the second, the actuation displacement for a given actuation load is maximized, subject to the same constraints as in the first formulation. These optimizations have generated considerably improved designs, making the actuators capable of large-displacement actuations with small actuating loads.

  5. Optical knife-edge displacement sensor for high-speed atomic force microscopy

    SciTech Connect

    Braunsmann, Christoph; Schäffer, Tilman E.; Prucker, Veronika

    2014-03-10

    We show that an optical knife-edge technique can be used to detect the parallel shift of an object with sub-nanometer resolution over a wide bandwidth. This allows to design simple, contact-free, and high-speed displacement sensors that can be implemented in high-speed atomic force microscope scanners. In an experimental setup, we achieved a root-mean-square sensor noise of 0.8 nm within a bandwidth from 1 Hz to 1.1 MHz. We used this sensor to detect and correct the nonlinear z-piezo displacement during force curves acquired with rates of up to 5 kHz. We discuss the fundamental resolution limit and the linearity of the sensor.

  6. Atomic Force Microscopy in Dynamic Mode with Displacement Current Detection in Double Cantilever Devices

    NASA Astrophysics Data System (ADS)

    Müller, Falk; Müller, Anne‑Dorothea; Hietschold, Michael; Gessner, Thomas

    2006-03-01

    A cantilever array for dynamic mode atomic force microscopy (AFM) is presented, the vertical displacement of which is analyzed by the detection of displacement currents in the electrodes. Each cantilever in the array consists of an actuation part that allows an independent vertical movement, and a sensor part. The lateral distance between the tips of the different cantilevers is fixed to 10 μm. When operated as an actuator, a voltage is applied between the silicon membrane and the underlaying electrode. Due to the resulting coulomb forces, the vertical position of the tip is controllable. The reaction time in this mode is shorter than the response time of a piezostack. The sensor part, on the other hand, allows the device to work in dynamic mode without a laser deflection system. The vertical resolution achieved is below 1 nm. The dependence of force distance curves on the excitation amplitude is shown.

  7. Temperature dependent local atomic displacements in ammonia intercalated iron selenide superconductor.

    PubMed

    Paris, E; Simonelli, L; Wakita, T; Marini, C; Lee, J-H; Olszewski, W; Terashima, K; Kakuto, T; Nishimoto, N; Kimura, T; Kudo, K; Kambe, T; Nohara, M; Yokoya, T; Saini, N L

    2016-01-01

    Recently, ammonia-thermal reaction has been used for molecular intercalation in layered FeSe, resulting a new Lix(NH3)yFe2Se2 superconductor with Tc ~ 45 K. Here, we have used temperature dependent extended x-ray absorption fine structure (EXAFS) to investigate local atomic displacements in single crystals of this new superconductor. Using polarized EXAFS at Fe K-edge we have obtained direct information on the local Fe-Se and Fe-Fe bondlengths and corresponding mean square relative displacements (MSRD). We find that the Se-height in the intercalated system is lower than the one in the binary FeSe, suggesting compressed FeSe4 tetrahedron in the title system. Incidentally, there is hardly any effect of the intercalation on the bondlengths characteristics, revealed by the Einstein temperatures, that are similar to those found in the binary FeSe. Therefore, the molecular intercalation induces an effective compression and decouples the FeSe slabs. Furthermore, the results reveal an anomalous change in the atomic correlations across Tc, appearing as a clear decrease in the MSRD, indicating hardening of the local lattice mode. Similar response of the local lattice has been found in other families of superconductors, e.g., A15-type and cuprates superconductors. This observation suggests that local atomic correlations should have some direct correlation with the superconductivity. PMID:27276997

  8. Temperature dependent local atomic displacements in ammonia intercalated iron selenide superconductor

    NASA Astrophysics Data System (ADS)

    Paris, E.; Simonelli, L.; Wakita, T.; Marini, C.; Lee, J.-H.; Olszewski, W.; Terashima, K.; Kakuto, T.; Nishimoto, N.; Kimura, T.; Kudo, K.; Kambe, T.; Nohara, M.; Yokoya, T.; Saini, N. L.

    2016-06-01

    Recently, ammonia-thermal reaction has been used for molecular intercalation in layered FeSe, resulting a new Lix(NH3)yFe2Se2 superconductor with Tc ~ 45 K. Here, we have used temperature dependent extended x-ray absorption fine structure (EXAFS) to investigate local atomic displacements in single crystals of this new superconductor. Using polarized EXAFS at Fe K-edge we have obtained direct information on the local Fe-Se and Fe-Fe bondlengths and corresponding mean square relative displacements (MSRD). We find that the Se-height in the intercalated system is lower than the one in the binary FeSe, suggesting compressed FeSe4 tetrahedron in the title system. Incidentally, there is hardly any effect of the intercalation on the bondlengths characteristics, revealed by the Einstein temperatures, that are similar to those found in the binary FeSe. Therefore, the molecular intercalation induces an effective compression and decouples the FeSe slabs. Furthermore, the results reveal an anomalous change in the atomic correlations across Tc, appearing as a clear decrease in the MSRD, indicating hardening of the local lattice mode. Similar response of the local lattice has been found in other families of superconductors, e.g., A15-type and cuprates superconductors. This observation suggests that local atomic correlations should have some direct correlation with the superconductivity.

  9. Temperature dependent local atomic displacements in ammonia intercalated iron selenide superconductor

    PubMed Central

    Paris, E.; Simonelli, L.; Wakita, T.; Marini, C.; Lee, J.-H.; Olszewski, W.; Terashima, K.; Kakuto, T.; Nishimoto, N.; Kimura, T.; Kudo, K.; Kambe, T.; Nohara, M.; Yokoya, T.; Saini, N. L.

    2016-01-01

    Recently, ammonia-thermal reaction has been used for molecular intercalation in layered FeSe, resulting a new Lix(NH3)yFe2Se2 superconductor with Tc ~ 45 K. Here, we have used temperature dependent extended x-ray absorption fine structure (EXAFS) to investigate local atomic displacements in single crystals of this new superconductor. Using polarized EXAFS at Fe K-edge we have obtained direct information on the local Fe-Se and Fe-Fe bondlengths and corresponding mean square relative displacements (MSRD). We find that the Se-height in the intercalated system is lower than the one in the binary FeSe, suggesting compressed FeSe4 tetrahedron in the title system. Incidentally, there is hardly any effect of the intercalation on the bondlengths characteristics, revealed by the Einstein temperatures, that are similar to those found in the binary FeSe. Therefore, the molecular intercalation induces an effective compression and decouples the FeSe slabs. Furthermore, the results reveal an anomalous change in the atomic correlations across Tc, appearing as a clear decrease in the MSRD, indicating hardening of the local lattice mode. Similar response of the local lattice has been found in other families of superconductors, e.g., A15-type and cuprates superconductors. This observation suggests that local atomic correlations should have some direct correlation with the superconductivity. PMID:27276997

  10. Bandgap modulation in photoexcited topological insulator Bi2Te3 via atomic displacements.

    PubMed

    Hada, Masaki; Norimatsu, Katsura; Tanaka, Sei Ichi; Keskin, Sercan; Tsuruta, Tetsuya; Igarashi, Kyushiro; Ishikawa, Tadahiko; Kayanuma, Yosuke; Miller, R J Dwayne; Onda, Ken; Sasagawa, Takao; Koshihara, Shin-Ya; Nakamura, Kazutaka G

    2016-07-14

    The atomic and electronic dynamics in the topological insulator (TI) Bi2Te3 under strong photoexcitation were characterized with time-resolved electron diffraction and time-resolved mid-infrared spectroscopy. Three-dimensional TIs characterized as bulk insulators with an electronic conduction surface band have shown a variety of exotic responses in terms of electronic transport when observed under conditions of applied pressure, magnetic field, or circularly polarized light. However, the atomic motions and their correlation between electronic systems in TIs under strong photoexcitation have not been explored. The artificial and transient modification of the electronic structures in TIs via photoinduced atomic motions represents a novel mechanism for providing a comparable level of bandgap control. The results of time-domain crystallography indicate that photoexcitation induces two-step atomic motions: first bismuth and then tellurium center-symmetric displacements. These atomic motions in Bi2Te3 trigger 10% bulk bandgap narrowing, which is consistent with the time-resolved mid-infrared spectroscopy results. PMID:27421417

  11. Bandgap modulation in photoexcited topological insulator Bi2Te3 via atomic displacements

    NASA Astrophysics Data System (ADS)

    Hada, Masaki; Norimatsu, Katsura; Tanaka, Sei'ichi; Keskin, Sercan; Tsuruta, Tetsuya; Igarashi, Kyushiro; Ishikawa, Tadahiko; Kayanuma, Yosuke; Miller, R. J. Dwayne; Onda, Ken; Sasagawa, Takao; Koshihara, Shin-ya; Nakamura, Kazutaka G.

    2016-07-01

    The atomic and electronic dynamics in the topological insulator (TI) Bi2Te3 under strong photoexcitation were characterized with time-resolved electron diffraction and time-resolved mid-infrared spectroscopy. Three-dimensional TIs characterized as bulk insulators with an electronic conduction surface band have shown a variety of exotic responses in terms of electronic transport when observed under conditions of applied pressure, magnetic field, or circularly polarized light. However, the atomic motions and their correlation between electronic systems in TIs under strong photoexcitation have not been explored. The artificial and transient modification of the electronic structures in TIs via photoinduced atomic motions represents a novel mechanism for providing a comparable level of bandgap control. The results of time-domain crystallography indicate that photoexcitation induces two-step atomic motions: first bismuth and then tellurium center-symmetric displacements. These atomic motions in Bi2Te3 trigger 10% bulk bandgap narrowing, which is consistent with the time-resolved mid-infrared spectroscopy results.

  12. Observation of atomic scale compositional and displacive modulations in incommensurate melilite electrolytes

    SciTech Connect

    Wei, Fengxia; Williams, Tim; An, Tao; Baikie, Tom; Kloc, Christian; Wei, Jun; White, Tim

    2013-07-15

    The paradigm that functional materials are adequately described as three-dimensional crystal structures is not universally tenable. Gallate melilites are efficient oxide ion conductors at intermediate temperatures (∼750 °C) with non-rational crystallographic modulations presumed to play a key role in significantly enhancing oxygen mobility. Lattice distortions associated with incommensuration are usually extrapolated from diffraction analysis of volumes greatly exceeding the scale of modulation. Therefore, opportunities for making direct nanometric measurements are exceptionally valuable for correlating structure with function. In [CaLn]{sub 2}[Ga]{sub 2}[Ga{sub 2}O{sub 7}]{sub 2} (Ln=Nd, La) melilites, atomic displacive and compositional modulation waves can be imaged by high angle annular dark field and bright field scanning transmission electron microscopy with contrast quantified through electron scattering simulation. Here, we present atomic scale observations of (3+2)-dimensional modulations in gallate melilites which expands our understanding of the ion conduction mechanism and provides guidance for enhancing the performance of solid oxide fuel cells through crystal chemical tailoring. - Highlights: • Characterise the (3+2)-dimensional melilite electrolytes using STEM technique. • Direct observation on displacive and compositional modulation in melilites. • Structural flexibility reduces when increasing interstitial oxygen. • Domain-like incommensurate modulation model is proposed.

  13. Characterizing absolute piezoelectric microelectromechanical system displacement using an atomic force microscope

    SciTech Connect

    Evans, J. Chapman, S.

    2014-08-14

    Piezoresponse Force Microscopy (PFM) is a popular tool for the study of ferroelectric and piezoelectric materials at the nanometer level. Progress in the development of piezoelectric MEMS fabrication is highlighting the need to characterize absolute displacement at the nanometer and Ångstrom scales, something Atomic Force Microscopy (AFM) might do but PFM cannot. Absolute displacement is measured by executing a polarization measurement of the ferroelectric or piezoelectric capacitor in question while monitoring the absolute vertical position of the sample surface with a stationary AFM cantilever. Two issues dominate the execution and precision of such a measurement: (1) the small amplitude of the electrical signal from the AFM at the Ångstrom level and (2) calibration of the AFM. The authors have developed a calibration routine and test technique for mitigating the two issues, making it possible to use an atomic force microscope to measure both the movement of a capacitor surface as well as the motion of a micro-machine structure actuated by that capacitor. The theory, procedures, pitfalls, and results of using an AFM for absolute piezoelectric measurement are provided.

  14. Atomic motion from the mean square displacement in a monatomic liquid.

    PubMed

    Wallace, Duane C; De Lorenzi-Venneri, Giulia; Chisolm, Eric D

    2016-05-11

    V-T theory is constructed in the many-body Hamiltonian formulation, and is being developed as a novel approach to liquid dynamics theory. In this theory the liquid atomic motion consists of two contributions, normal mode vibrations in a single representative potential energy valley, and transits, which carry the system across boundaries between valleys. The mean square displacement time correlation function (the MSD) is a direct measure of the atomic motion, and our goal is to determine if the V-T formalism can produce a physically sensible account of this motion. We employ molecular dynamics (MD) data for a system representing liquid Na, and find the motion evolves in three successive time intervals: on the first 'vibrational' interval, the vibrational motion alone gives a highly accurate account of the MD data; on the second 'crossover' interval, the vibrational MSD saturates to a constant while the transit motion builds up from zero; on the third 'random walk' interval, the transit motion produces a purely diffusive random walk of the vibrational equilibrium positions. This motional evolution agrees with, and adds refinement to, the MSD atomic motion as described by current liquid dynamics theories. PMID:27058024

  15. Atomic motion from the mean square displacement in a monatomic liquid

    NASA Astrophysics Data System (ADS)

    Wallace, Duane C.; De Lorenzi-Venneri, Giulia; Chisolm, Eric D.

    2016-05-01

    V-T theory is constructed in the many-body Hamiltonian formulation, and is being developed as a novel approach to liquid dynamics theory. In this theory the liquid atomic motion consists of two contributions, normal mode vibrations in a single representative potential energy valley, and transits, which carry the system across boundaries between valleys. The mean square displacement time correlation function (the MSD) is a direct measure of the atomic motion, and our goal is to determine if the V-T formalism can produce a physically sensible account of this motion. We employ molecular dynamics (MD) data for a system representing liquid Na, and find the motion evolves in three successive time intervals: on the first ‘vibrational’ interval, the vibrational motion alone gives a highly accurate account of the MD data; on the second ‘crossover’ interval, the vibrational MSD saturates to a constant while the transit motion builds up from zero; on the third ‘random walk’ interval, the transit motion produces a purely diffusive random walk of the vibrational equilibrium positions. This motional evolution agrees with, and adds refinement to, the MSD atomic motion as described by current liquid dynamics theories.

  16. Atomic motion from the mean square displacement in a monatomic liquid

    DOE PAGESBeta

    Wallace, Duane C.; De Lorenzi-Venneri, Giulia; Chisolm, Eric D.

    2016-05-11

    V-T theory is constructed in the many-body Hamiltonian formulation, and is being developed as a novel approach to liquid dynamics theory. In this theory the liquid atomic motion consists of two contributions, normal mode vibrations in a single representative potential energy valley, and transits, which carry the system across boundaries between valleys. The mean square displacement time correlation function (the MSD) is a direct measure of the atomic motion, and our goal is to determine if the V-T formalism can produce a physically sensible account of this motion. We employ molecular dynamics (MD) data for a system representing liquid Na,more » and find the motion evolves in three successive time intervals: on the first 'vibrational' interval, the vibrational motion alone gives a highly accurate account of the MD data; on the second 'crossover' interval, the vibrational MSD saturates to a constant while the transit motion builds up from zero; on the third 'random walk' interval, the transit motion produces a purely diffusive random walk of the vibrational equilibrium positions. Furthermore, this motional evolution agrees with, and adds refinement to, the MSD atomic motion as described by current liquid dynamics theories.« less

  17. Observations of sudden large scale upward displacements of the Martian ionosphere

    NASA Astrophysics Data System (ADS)

    Upadhayaya, Arun Kumar; Mahajan, K. K.; Gupta, Sumedha

    2016-07-01

    We have analyzed most of the 5600 electron density profiles measured by the MGS Radio Science Experiment and have observed that even when the well known parameters controlling ion production and loss seem to remain constant, the density (NmF1) and height (hmF1) of the primary ionospheric peak show large scale variations. We note that on some days, hmF1 suddenly moves up by more than 14 km between consecutive measurements (which are about two hours apart) and this upward displacement is seen at all altitudes. During these displacements, the peak density and ionospheric total electron content decrease while the slab thickness shows an increase. Further, there is some evidence of a seasonal component in the occurrence of these episodes. F1 layer is in photochemical equilibrium and is isobaric. Therefore, these upward displacements indicate that the Martian neutral atmosphere is subject to sudden and large scale surges.

  18. Continuous atomic spectrometric measurement of ambient levels of sulfur dioxide in air by mercury displacement detection

    SciTech Connect

    Marshall, G.; Midgley, D.

    1982-08-01

    The analytical atomic spectrometric technique of mercury displacement detection has been adapted so that sulfur dioxide can be determined at natural background levels in ambient air on a continuous basis with a 90% response time of 1-2 min. Sample air is drawn into the reaction vessel containing mercury (I) ion reagent and any sulfur dioxide present reacts to form elemental mercury which is measured, after being swept out of the solution by the same flow of sample air, by a mercury vapor detector. Reagent is continuously pumped through the analyzer and the instrument is calibrated with a permeation tube calibrator. The apparatus has a linear concentration range up to 100 ppB sulfur dioxide; this is much lower than can be obtained with existing commerical instruments. The apparatus is very precise and 6, 11, and 20 ppB sulfur dioxide can be measured with coefficients of variation of 1-2%.

  19. Anisotropic atom displacement in Pd nanocubes resolved by molecular dynamics simulations supported by x-ray diffraction imaging

    NASA Astrophysics Data System (ADS)

    Scardi, P.; Leonardi, A.; Gelisio, L.; Suchomel, M. R.; Sneed, B. T.; Sheehan, M. K.; Tsung, C.-K.

    2015-04-01

    Nearly identical Pd nanocubes yield an x-ray powder diffraction pattern with interference fringes affording access to unprecedented structural details of nanocrystal size, shape, and complex atomic displacement for a billion-sized population. The excellent agreement between diffraction data and molecular dynamics (MD) provides strong experimental validation of MD simulations and the proposed data-interpretation paradigm. These results show that individual atomic displacements within the nanocubes are not only a function of disrupted bonds and the crystallographic plane of the adjacent surface, but are complex strain gradients extending across all surfaces of the particle strongly influenced by atomic displacements. This observation of nonuniform surface strain and the manner in which it is affected by different sizes, shapes, and locations within each facet could be the key to understanding many surface related properties of shaped nanocrystals including those associated with important catalysis applications.

  20. Evolution of the superposition of displaced number states with the two-atom multiphoton Jaynes Cummings model: interference and entanglement

    NASA Astrophysics Data System (ADS)

    El-Orany, Faisal A. A.

    2006-11-01

    In this paper, we study the evolution of two two-level atoms interacting with a single-mode quantized radiation field, namely, the two-atom multiphoton Jaynes-Cummings model (JCM). We assume that the field and the atoms are initially prepared in the superposition of displaced number states and excited atomic states, respectively. For this system, we investigate the atomic inversion, Wigner function, phase distribution and entanglement. We show that for symmetric (asymmetric) atoms, the system can generate asymmetric (symmetric) cat states at a quarter of the revival time. Furthermore, the degrees of entanglement for the field-atoms and the one-atom-remainder tangles depend on the rate of energy flow between the parties. The interference in phase space decreases the degree of entanglement in the bipartite.

  1. A spongy graphene based bimorph actuator with ultra-large displacement towards biomimetic application.

    PubMed

    Hu, Ying; Lan, Tian; Wu, Guan; Zhu, Zicai; Chen, Wei

    2014-11-01

    Bimorph actuators, consisting of two layers with asymmetric expansion and generating bending displacement, have been widely researched. Their actuation performances greatly rely on the difference of coefficients of thermal expansion (CTE) between the two material layers. Here, by introducing a spongy graphene (sG) paper with a large negative CTE as well as high electrical-to-thermal properties, an electromechanical sG/PDMS bimorph actuator is designed and fabricated, showing an ultra-large bending displacement output under low voltage stimulation (curvature of about 1.2 cm(-1) at 10 V for 3 s), a high displacement-to-length ratio (∼0.79), and vibration motion at AC voltage (up to 10 Hz), which is much larger and faster than that of the other electromechanical bimorph actuators. Based on the sG/PDMS bimorph serving as the "finger", a mechanical gripper is constructed to realize the fast manipulation of the objects under 0.1 Hz square wave voltage stimulation (0-8 V). The designed bimorph actuator coupled with ultra-large bending displacement, low driven voltage, and the ease of fabrication may open up substantial possibilities for the utilization of electromechanical actuators in practical biomimetic device applications. PMID:25220910

  2. Development of steel dampers for bridges to allow large displacement through a vertical free mechanism

    NASA Astrophysics Data System (ADS)

    Pan, Peng; Yan, Hong; Wang, Tao; Xu, Peizhen; Xie, Qiang

    2014-09-01

    Isolation bearings and dampers are often installed between piers and superstructures to reduce the seismic responses of bridges under large earthquakes. This paper presents a novel steel damper for bridges. The damper employs steel plates as energy dissipation components, and adopts a vertical free mechanism to achieve a large deformation capacity. Quasi-static tests using displacement-controlled cyclic loading and numerical analyses using a finite element program called ABAQUS are conducted to investigate the behavior of the damper, and a design methodology is proposed based on the tests and numerical analyses. Major conclusions obtained from this study are as follows: (1) the new dampers have stable hysteresis behavior under large displacements; (2) finite element analyses are able to simulate the behavior of the damper with satisfactory accuracy; and (3) simplified design methodology of the damper is effective.

  3. Large amplitude free vibrations of Timoshenko beams at higher modes using coupled displacement field method

    NASA Astrophysics Data System (ADS)

    Krishna Bhaskar, K.; Meera Saheb, K.

    2015-12-01

    A simple but accurate continuum solution for the shear flexible beam problem using the energy method involves in assuming suitable single term admissible functions for the lateral displacement and total rotation. This leads to two non-linear temporal differential equations in terms of the lateral displacement and the total rotation and are difficult, if not impossible, to solve to obtain the large amplitude fundamental frequencies of beams as a function of the amplitude and slenderness ratios of the vibrating beam. This situation can be avoided if one uses the concept of coupled displacement field where in the fields for lateral displacement and the total rotation are coupled through the static equilibrium equation. In this paper the lateral displacement field is assumed and the field for the total rotation is evaluated through the coupling equation. This approach leads to only one undetermined coefficient which can easily be used in the principle of conservation of total energy of the vibrating beam at a given time, neglecting damping. Finally, through a number of algebraic manipulations, one gets a nonlinear equation of Duffing type which can be solved using any standard method. To demonstrate the simplicity of the method discussed above the problem of large amplitude free vibrations of a uniform shear flexible hinged beam at higher modes with ends immovable to move axially has been solved. The numerical results obtained from the present formulation are in very good agreement with those obtained through finite element and other continuum methods for the fundamental mode, thus demonstrating the efficacy of the proposed method. Also some interesting observations are made with variation of frequency Vs amplitude at different modes.

  4. Large Out-of-Plane Displacement Bistable Electromagnetic Microswitch on a Single Wafer.

    PubMed

    Miao, Xiaodan; Dai, Xuhan; Huang, Yi; Ding, Guifu; Zhao, Xiaolin

    2016-01-01

    This paper presents a bistable microswitch fully batch-fabricated on a single glass wafer, comprising of a microactuator, a signal transformer, a microspring and a permanent magnet. The bistable mechanism of the microswitch with large displacement of 160 μm depends on the balance of the magnetic force and elastic force. Both the magnetic force and elastic force were optimized by finite-element simulation to predict the reliable of the device. The prototype was fabricated and characterized. By utilizing thick laminated photoresist sacrificial layer, the large displacement was obtained to ensure the insulation of the microswitch. The testing results show that the microswitch realized the bistable mechanism at a 3-5 V input voltage and closed in 0.96 ms, which verified the simulation. PMID:27164107

  5. Long-delayed bright dancing sprite with large horizontal displacement from its parent flash

    NASA Astrophysics Data System (ADS)

    Yang, J.; Lu, G.; Lee, L. J.; Feng, G.

    2015-12-01

    A long-delayed very bright dancing sprite with large horizontal displacement from its parent flash was observed. The dancing sprite lasted only 60 ms, and the morphology consisted of three fields with two slim dim sprite elements in the first two fields and a very bright large sprite element in the third field, different from other observations. The bright sprite displaced at least 38 km from its parent flash and occurred over comparatively higher cloud top region. The parent flash was positive, with only one return stroke (~24 kA) and obvious continuing current process, and the charge moment change of the stroke was small (roughly the threshold for sprite production). All of the sprite elements occurred during the continuing current period, and the bright sprite induced considerable current. The sprite dancing features may be linked to parent storm electrical structure, dynamics and microphysics, and the parent CG discharge process which was consistent with VHF observations.

  6. Large Out-of-Plane Displacement Bistable Electromagnetic Microswitch on a Single Wafer

    PubMed Central

    Miao, Xiaodan; Dai, Xuhan; Huang, Yi; Ding, Guifu; Zhao, Xiaolin

    2016-01-01

    This paper presents a bistable microswitch fully batch-fabricated on a single glass wafer, comprising of a microactuator, a signal transformer, a microspring and a permanent magnet. The bistable mechanism of the microswitch with large displacement of 160 μm depends on the balance of the magnetic force and elastic force. Both the magnetic force and elastic force were optimized by finite-element simulation to predict the reliable of the device. The prototype was fabricated and characterized. By utilizing thick laminated photoresist sacrificial layer, the large displacement was obtained to ensure the insulation of the microswitch. The testing results show that the microswitch realized the bistable mechanism at a 3–5 V input voltage and closed in 0.96 ms, which verified the simulation. PMID:27164107

  7. Analysis, construction, and testing of a large displacement bistable piezoelectric actuator

    NASA Astrophysics Data System (ADS)

    Monreal, J.; Giannopoulos, G.; Vantomme, J.

    2007-04-01

    Piezoelectric structures are used in a variety of applications where instant response, high energy conversion efficiency and accurate control are required. However, in the actuation domain they present an important drawback, which is the small displacement capacity. In the present work non-linear mechanics and more specifically snap-through buckling are used to transform a traditional bimorph structure with two piezoelectric layers and an aluminum substrate into a non-linear high displacement actuator with increased combination of force/displacement output. Large displacements are attained with the transition of the structure from one equilibrium position to another. A closed form analytical solution for the snap-through behavior of piezoelectric/composite beams is presented. The effect of piezoelectric actuation is introduced in this model through equivalent bending moments produced through the bimorph setting of the piezoelectric actuator. Classical Laminated Plate Theory (CLPT) is used for the elaboration of an equivalent single layer structure that takes into account the influence on the stiffness of the structure due to the piezoelectric layers. During the development the importance of boundary conditions has been revealed and thus it has been modeled too. Results from finite element analysis as well as the actuators' construction and the experimental setup and subsequent results are presented.

  8. Calculated sputtering and atomic displacement cross-sections for applications to medium voltage analytical electron microscopy

    SciTech Connect

    Bradley, C.R.; Zaluzec, N.J.

    1987-08-01

    The development of medium voltage electron microscopes having high brightness electron sources and ultra-high vacuum environments has been anticipated by the microscopy community now for several years. The advantages of such a configuration have been discussed to great lengths, while the potential disadvantages have for the most part been neglected. The most detrimental of these relative to microcharacterization are the effects of electron sputtering and atomic displacement to the local specimen composition. These effects have in the past been considered mainly in the high voltage electron microscope regime and generally were ignored in lower voltage instruments. Recent experimental measurements have shown that the effects of electron sputtering as well as radiation induced segregation can be observed in conventional transmission electron microscopes. It is, therefore, important to determine at what point the effects will begin to manifest themselves in the new generation of medium voltage analytical electron microscopes. In this manuscript we present new calculations which allow the individual experimentalist to determine the potential threshold levels for a particular elemental system and thus avoid the dangers of introducing artifacts during microanalysis. 12 refs., 3 figs.

  9. Large Displacement in Relaxor Ferroelectric Terpolymer Blend Derived Actuators Using Al Electrode for Braille Displays

    PubMed Central

    Lu, S. G.; Chen, X.; Levard, T.; Diglio, P. J.; Gorny, L. J.; Rahn, C. D.; Zhang, Q. M.

    2015-01-01

    Poly(vinylidene fluoride) (PVDF) based polymers are attractive for applications for artificial muscles, high energy density storage devices etc. Recently these polymers have been found great potential for being used as actuators for refreshable full-page Braille displays for visually impaired people in terms of light weight, miniaturized size, and larger displacement, compared with currently used lead zirconate titanate ceramic actuators. The applied voltages of published polymer actuators, however, cannot be reduced to meet the requirements of using city power. Here, we report the polymer actuator generating quite large displacement and blocking force at a voltage close to the city power. Our embodiments also show good self-healing performance and disuse of lead-containing material, which makes the Braille device safer, more reliable and more environment-friendly. PMID:26079628

  10. Large-Deformation Displacement Transfer Functions for Shape Predictions of Highly Flexible Slender Aerospace Structures

    NASA Technical Reports Server (NTRS)

    Ko, William L.; Fleischer, Van Tran

    2013-01-01

    Large deformation displacement transfer functions were formulated for deformed shape predictions of highly flexible slender structures like aircraft wings. In the formulation, the embedded beam (depth wise cross section of structure along the surface strain sensing line) was first evenly discretized into multiple small domains, with surface strain sensing stations located at the domain junctures. Thus, the surface strain (bending strains) variation within each domain could be expressed with linear of nonlinear function. Such piecewise approach enabled piecewise integrations of the embedded beam curvature equations [classical (Eulerian), physical (Lagrangian), and shifted curvature equations] to yield closed form slope and deflection equations in recursive forms.

  11. On 'large-scale' stable fiber displacement during interfacial failure in metal matrix composites

    NASA Technical Reports Server (NTRS)

    Petrich, R. R.; Koss, D. A.; Hellmann, J. R.; Kallas, M. N.

    1993-01-01

    Experimental results are presented to show that interfacial failure in sapphire-reinforced niobium is characterized by 'large-scale' (5-15 microns) plasticity-controlled fiber displacements occurring under increasing loads. The results are based on the responses during thin-slice fiber pushout tests wherein the fiber is supported over a hole twice the fiber diameter. The results describe an interfacial failure process that should also occur near fiber ends during pullout when a fiber is well-bonded to a soft, ductile matrix, such that eventual failure occurs by shear within the matrix near the interface.

  12. Exploiting Universality in Atoms with Large Scattering Lengths

    SciTech Connect

    Braaten, Eric

    2012-05-31

    The focus of this research project was atoms with scattering lengths that are large compared to the range of their interactions and which therefore exhibit universal behavior at sufficiently low energies. Recent dramatic advances in cooling atoms and in manipulating their scattering lengths have made this phenomenon of practical importance for controlling ultracold atoms and molecules. This research project was aimed at developing a systematically improvable method for calculating few-body observables for atoms with large scattering lengths starting from the universal results as a first approximation. Significant progress towards this goal was made during the five years of the project.

  13. A metrological large range atomic force microscope with improved performance

    NASA Astrophysics Data System (ADS)

    Dai, Gaoliang; Wolff, Helmut; Pohlenz, Frank; Danzebrink, Hans-Ulrich

    2009-04-01

    A metrological large range atomic force microscope (Met. LR-AFM) has been set up and improved over the past years at Physikalisch-Technische Bundesanstalt (PTB). Being designed as a scanning sample type instrument, the sample is moved in three dimensions by a mechanical ball bearing stage in combination with a compact z-piezostage. Its topography is detected by a position-stationary AFM head. The sample displacement is measured by three embedded miniature homodyne interferometers in the x, y, and z directions. The AFM head is aligned in such a way that its cantilever tip is positioned on the sample surface at the intersection point of the three interferometer measurement beams for satisfying the Abbe measurement principle. In this paper, further improvements of the Met. LR-AFM are reported. A new AFM head using the beam deflection principle has been developed to reduce the influence of parasitic optical interference phenomena. Furthermore, an off-line Heydemann correction method has been applied to reduce the inherent interferometer nonlinearities to less than 0.3 nm (p-v). Versatile scanning functions, for example, radial scanning or local AFM measurement functions, have been implemented to optimize the measurement process. The measurement software is also improved and allows comfortable operations of the instrument via graphical user interface or script-based command sets. The improved Met. LR-AFM is capable of measuring, for instance, the step height, lateral pitch, line width, nanoroughness, and other geometrical parameters of nanostructures. Calibration results of a one-dimensional grating and a set of film thickness standards are demonstrated, showing the excellent metrological performance of the instrument.

  14. A metrological large range atomic force microscope with improved performance

    SciTech Connect

    Dai, Gaoliang; Wolff, Helmut; Pohlenz, Frank; Danzebrink, Hans-Ulrich

    2009-04-15

    A metrological large range atomic force microscope (Met. LR-AFM) has been set up and improved over the past years at Physikalisch-Technische Bundesanstalt (PTB). Being designed as a scanning sample type instrument, the sample is moved in three dimensions by a mechanical ball bearing stage in combination with a compact z-piezostage. Its topography is detected by a position-stationary AFM head. The sample displacement is measured by three embedded miniature homodyne interferometers in the x, y, and z directions. The AFM head is aligned in such a way that its cantilever tip is positioned on the sample surface at the intersection point of the three interferometer measurement beams for satisfying the Abbe measurement principle. In this paper, further improvements of the Met. LR-AFM are reported. A new AFM head using the beam deflection principle has been developed to reduce the influence of parasitic optical interference phenomena. Furthermore, an off-line Heydemann correction method has been applied to reduce the inherent interferometer nonlinearities to less than 0.3 nm (p-v). Versatile scanning functions, for example, radial scanning or local AFM measurement functions, have been implemented to optimize the measurement process. The measurement software is also improved and allows comfortable operations of the instrument via graphical user interface or script-based command sets. The improved Met. LR-AFM is capable of measuring, for instance, the step height, lateral pitch, line width, nanoroughness, and other geometrical parameters of nanostructures. Calibration results of a one-dimensional grating and a set of film thickness standards are demonstrated, showing the excellent metrological performance of the instrument.

  15. A metrological large range atomic force microscope with improved performance.

    PubMed

    Dai, Gaoliang; Wolff, Helmut; Pohlenz, Frank; Danzebrink, Hans-Ulrich

    2009-04-01

    A metrological large range atomic force microscope (Met. LR-AFM) has been set up and improved over the past years at Physikalisch-Technische Bundesanstalt (PTB). Being designed as a scanning sample type instrument, the sample is moved in three dimensions by a mechanical ball bearing stage in combination with a compact z-piezostage. Its topography is detected by a position-stationary AFM head. The sample displacement is measured by three embedded miniature homodyne interferometers in the x, y, and z directions. The AFM head is aligned in such a way that its cantilever tip is positioned on the sample surface at the intersection point of the three interferometer measurement beams for satisfying the Abbe measurement principle. In this paper, further improvements of the Met. LR-AFM are reported. A new AFM head using the beam deflection principle has been developed to reduce the influence of parasitic optical interference phenomena. Furthermore, an off-line Heydemann correction method has been applied to reduce the inherent interferometer nonlinearities to less than 0.3 nm (p-v). Versatile scanning functions, for example, radial scanning or local AFM measurement functions, have been implemented to optimize the measurement process. The measurement software is also improved and allows comfortable operations of the instrument via graphical user interface or script-based command sets. The improved Met. LR-AFM is capable of measuring, for instance, the step height, lateral pitch, line width, nanoroughness, and other geometrical parameters of nanostructures. Calibration results of a one-dimensional grating and a set of film thickness standards are demonstrated, showing the excellent metrological performance of the instrument. PMID:19405661

  16. Evidence for large-scale effects of competition: niche displacement in Canada lynx and bobcat

    PubMed Central

    Peers, Michael J. L.; Thornton, Daniel H.; Murray, Dennis L.

    2013-01-01

    Determining the patterns, causes and consequences of character displacement is central to our understanding of competition in ecological communities. However, the majority of competition research has occurred over small spatial extents or focused on fine-scale differences in morphology or behaviour. The effects of competition on broad-scale distribution and niche characteristics of species remain poorly understood but critically important. Using range-wide species distribution models, we evaluated whether Canada lynx (Lynx canadensis) or bobcat (Lynx rufus) were displaced in regions of sympatry. Consistent with our prediction, we found that lynx niches were less similar to those of bobcat in areas of sympatry versus allopatry, with a stronger reliance on snow cover driving lynx niche divergence in the sympatric zone. By contrast, bobcat increased niche breadth in zones of sympatry, and bobcat niches were equally similar to those of lynx in zones of sympatry and allopatry. These findings suggest that competitively disadvantaged species avoid competition at large scales by restricting their niche to highly suitable conditions, while superior competitors expand the diversity of environments used. Our results indicate that competition can manifest within climatic niche space across species’ ranges, highlighting the importance of biotic interactions occurring at large spatial scales on niche dynamics. PMID:24174116

  17. Large displacement behavior of double parallelogram flexure mechanisms with underconstraint eliminators

    DOE PAGESBeta

    Panas, Robert M.

    2016-06-23

    This paper presents a new analytical method for predicting the large displacement behavior of flexural double parallelogram (DP) bearings with underconstraint eliminator (UE) linkages. This closed-form perturbative Euler analysis method is able to – for the first time – directly incorporate the elastomechanics of a discrete UE linkage, which is a hybrid flexure element that is linked to ground as well as both stages on the bearing. The models are used to understand a nested linkage UE design, however the method is extensible to other UE linkages. Design rules and figures-of-merit are extracted from the analysis models, which provide powerfulmore » tools for accelerating the design process. The models, rules and figures-of-merit enable the rapid design of a UE for a desired large displacement behavior, as well as providing a means for determining the limits of UE and DP structures. This will aid in the adoption of UE linkages into DP bearings for precision mechanisms. Models are generated for a nested linkage UE design, and the performance of this DP with UE structure is compared to a DP-only bearing. As a result, the perturbative Euler analysis is shown to match existing theories for DP-only bearings with distributed compliance within ≈2%, and Finite Element Analysis for the DP with UE bearings within an average 10%.« less

  18. GPS Seismology: Using Precise Point Positioning for Resolving Surface Wave Displacements from Large Earthquakes

    NASA Astrophysics Data System (ADS)

    Dragert, H.; Henton, J. A.; Lahaye, F.; Kouba, J.; Larson, K. M.; Rogers, G. C.

    2010-12-01

    High-rate continuous GPS data can provide direct, high-quality measurements of surface wave displacements generated by large earthquakes (Larson et al., 2003; Bock et al., 2004; Larson, 2009). To achieve high precision, differential positioning is often used in the GPS analysis strategy with distant reference stations held fixed. In this presentation, we examine the use of the Precise Point Positioning (PPP) technique to estimate epoch-by-epoch positions at single stations. Specifically, we use the PPP software developed by Natural Resources Canada (Heroux and Kouba, 2001) to analyze high-rate (5 Hz) GPS data collected at stations of the Plate Boundary Observatory (PBO) in southern California at the time of the M7.2 El Mayor-Cucapah Earthquake of April 4, 2010. The hypocenter for this earthquake was located in northern Baja California, approximately 50 km south of Mexicali on the US-Mexico border, at a depth of ~10 km. Large horizontal displacements were observed at a number of PBO GPS sites, with the largest peak-to-peak displacements exceeding 90 cm in the east-west component for 10-sec period waves observed at El Centro, CA (P496), located about 70 km northeast of the epicenter. The PPP technique clearly resolved surface waves with 1 to 2 cm amplitudes at sites more than 800 km away from the epicenter, illustrating that surface waves eventually reach even distant reference sites within the period of interest and can thereby introduce artifacts for differential GPS positioning. Fine-tuning of PPP methodology revealed the following: 1) Since the quality of a PPP solution will not be optimal until the carrier phase ambiguities have converged (tens of minutes), it is best to begin the analyses well before the arrival of seismic waves. To reduce computations, the data for this convergence period need not be high-rate; 2) The use of 5-second precise satellite clock sampling instead of the nominal 30-second clock sampling minimized clock interpolation errors and

  19. A study of temperature dependent local atomic displacements in a Ba(Fe1-xCox)2As2 superconductor.

    PubMed

    Hacisalihoglu, M Y; Paris, E; Joseph, B; Simonelli, L; Sato, T J; Mizokawa, T; Saini, N L

    2016-03-23

    We have studied the local structure of a Ba(Fe1-xCox)2As2 superconductor using temperature dependent extended X-ray absorption fine structure (EXAFS) measurements. Polarized EXAFS at the Fe K-edge on an optimally doped (x = 0.06) single crystal has permitted us to determine atomic displacements across the superconducting transition temperature (Tc). The Fe-As bondlength hardly shows any change with temperature; however, the Fe-Fe sublattice reveals a sharp anomaly across Tc, indicated by a significant drop in mean square relative displacements, similar to the one known for cuprates and A15-type superconductors. We have also found a large atomic disorder around the substituted Co, revealed by polarized Co K-edge EXAFS measurements. The Co-Fe/Co bonds are more flexible than the Fe-Fe bonds with the As-height in Co-containing tetrahedra being larger than the one in FeAs4. The results suggest that the local Fe-Fe bondlength fluctuations and the atomic disorder in this sub-lattice should have some important role in the superconductivity of Ba(Fe1-xCox)2As2 pnictides. PMID:26966734

  20. Ion-channeling study of anomalous atomic displacements at the superconducting transition in high-T sub c materials

    SciTech Connect

    Rehn, L.E.; Sharma, R.P.; Baldo, P.M.

    1990-06-01

    Ion channeling along the (001) direction in high-quality single crystals of (Y/Er)Ba{sub 2}Cu{sub 3}O{sub 7-x} revealed an abrupt change in displacements in the a-b plane of the Cu and O atoms at the superconducting transition, {Tc}; normal Debye-like'' vibrations were found for the Y/Er and Ba atoms. The anomalous change in Cu-O displacements was found to shift directly with stoichiometry-induced changes in {Tc}, implying a direct link between the observed phonon anomaly and the superconducting transition. Recent measurements of ion-channeling along the (001) axis in (Bi{sub 1.7}Pb{sub 0.3})Sr{sub 2}Ca{sub 1}Cu{sub 2}O{sub x} single-crystals revealed a similar change at {Tc}, suggesting that this phonon anomaly is a general feature of high-{Tc} superconductivity. In order to identify more specifically the crystallographic directions and displacement amplitudes associated with the anomalous phonon behavior, axial channeling scans using RBS, as well as characteristic x-ray production, were taken at several temperatures between 30 and 300K along the (301) and (331) directions of YBa{sub 2}Cu{sub 3}O{sub 7-x} single crystals. Twins present in the specimens, and the existing static atomic displacements present along these directions, caused the channeling to be poorer along these axes compared to the (001) direction. Also, a much stronger dependence of the minimum yield on depth was observed. However, since only one twin variant generally dominated over sufficiently wide areas of the specimens, reasonably good ({approximately}10%) minimum yields could be obtained along the appropriate (331) axis, and detwinned crystals produced good results along (301). 22 refs., 5 figs.

  1. BRIEF COMMUNICATION: Electrothermal bistability tuning in a large displacement micro actuator

    NASA Astrophysics Data System (ADS)

    Gerson, Y.; Krylov, S.; Ilic, B.

    2010-11-01

    We report on an approach allowing simple yet efficient tuning of the bistability properties in large displacement micro actuators. The devices fabricated from silicon on insulator (SOI) wafers using a deep reactive ion etching (DRIE)-based process incorporate elastic suspension realized as a pair of beams initially curved in-plane and are operated electrostatically by a comb-drive transducer. The curvature of beam and therefore the stability characteristics of the suspension are controlled by passing a current through the suspension and resistive heating the beam material. Experimental results, which are in good agreement with the finite elements model predictions, demonstrate the feasibility of the suggested approach and show that the application of a small tuning current increases the device deflection from 42 to 56 µm, allows adjustment of the critical snap-through and snap-back voltages and makes it possible the control of latching without an additional electrode. The approach can be efficiently implemented in electrical and optical switches and threshold inertial and mass sensors where the use of long displacement actuators with an adjustable bistability range is beneficial.

  2. Long-delayed bright dancing sprite with large Horizontal displacement from its parent flash

    NASA Astrophysics Data System (ADS)

    Yang, Jing; Lu, Gaopeng; Lee, Li-Jou; Feng, Guili

    2015-07-01

    We reported in this paper the observation of a very bright long-delayed dancing sprite with distinct horizontal displacement from its parent stroke. The dancing sprite lasted only 60 ms, and the morphology consisted of three fields with two slim dim sprite elements in the first two fields and a very bright large element in the third field, different from other observations where the dancing sprites usually contained multiple elements over a longer time interval, and the sprite shape and brightness in the video field are often similar to the previous fields. The bright sprite was displaced at least 38 km from its parent cloud-to-ground (CG) stroke and occurred over comparatively higher cloud top region. The parent flash of this compact dancing sprite was of positive polarity, with only one return stroke (approximately +24 kA) and obvious continuing current process, and the charge moment change of stroke was small (barely above the threshold for sprite production). All the sprite elements occurred during the continuing current stage, and the bright long-delayed sprite element induced a considerable current pulse. The dancing feature of this sprite may be linked to the electrical charge structure, dynamics and microphysics of parent storm, and the inferred development of parent CG flash was consistent with previous very high-frequency (VHF) observations of lightning in the same region.

  3. Nonlinear finite element formulation for the large displacement analysis in multibody system dynamics

    NASA Technical Reports Server (NTRS)

    Rismantab-Sany, J.; Chang, B.; Shabana, A. A.

    1989-01-01

    A total Lagrangian finite element formulation for the deformable bodies in multibody mechanical systems that undergo finite relative rotations is developed. The deformable bodies are discretized using finite element methods. The shape functions that are used to describe the displacement field are required to include the rigid body modes that describe only large translational displacements. This does not impose any limitations on the technique because most commonly used shape functions satisfy this requirement. The configuration of an element is defined using four sets of coordinate systems: Body, Element, Intermediate element, Global. The body coordinate system serves as a unique standard for the assembly of the elements forming the deformable body. The element coordinate system is rigidly attached to the element and therefore it translates and rotates with the element. The intermediate element coordinate system, whose axes are initially parallel to the element axes, has an origin which is rigidly attached to the origin of the body coordinate system and is used to conveniently describe the configuration of the element in undeformed state with respect to the body coordinate system.

  4. Large spin relaxation rates in trapped submerged-shell atoms

    SciTech Connect

    Connolly, Colin B.; Au, Yat Shan; Doret, S. Charles; Doyle, John M.; Ketterle, Wolfgang

    2010-01-15

    Spin relaxation due to atom-atom collisions is measured for magnetically trapped erbium and thulium atoms at a temperature near 500 mK. The rate constants for Er-Er and Tm-Tm collisions are 3.0x10{sup -10} and 1.1x10{sup -10} cm{sup 3} s{sup -1}, respectively, 2-3 orders of magnitude larger than those observed for highly magnetic S-state atoms. This is strong evidence for an additional, dominant, spin relaxation mechanism, electronic interaction anisotropy, in collisions between these 'submerged-shell,' Lnot =0 atoms. These large spin relaxation rates imply that evaporative cooling of these atoms in a magnetic trap will be highly inefficient.

  5. Large atom number Bose-Einstein condensate machines

    SciTech Connect

    Streed, Erik W.; Chikkatur, Ananth P.; Gustavson, Todd L.; Boyd, Micah; Torii, Yoshio; Schneble, Dominik; Campbell, Gretchen K.; Pritchard, David E.; Ketterle, Wolfgang

    2006-02-15

    We describe experimental setups for producing large Bose-Einstein condensates of {sup 23}Na and {sup 87}Rb. In both, a high-flux thermal atomic beam is decelerated by a Zeeman slower and is then captured and cooled in a magneto-optical trap. The atoms are then transferred into a cloverleaf-style Ioffe-Pritchard magnetic trap and cooled to quantum degeneracy with radio-frequency-induced forced evaporation. Typical condensates contain 20x10{sup 6} atoms. We discuss the similarities and differences between the techniques used for producing large {sup 87}Rb and {sup 23}Na condensates in the context of nearly identical setups.

  6. Charge-screening role of c -axis atomic displacements in YBa2Cu3O6 +x and related superconductors

    NASA Astrophysics Data System (ADS)

    Božin, E. S.; Huq, A.; Shen, Bing; Claus, H.; Kwok, W. K.; Tranquada, J. M.

    2016-02-01

    The importance of charge reservoir layers for supplying holes to the CuO2 planes of cuprate superconductors has long been recognized. Less attention has been paid to the screening of the charge transfer by the intervening ionic layers. We address this issue in the case of YBa2Cu3O6 +x , where CuO chains supply the holes for the planes. We present a simple dielectric-screening model that gives a linear correlation between the relative displacements of ions along the c axis, determined by neutron powder diffraction, and the hole density of the planes. Applying this model to the temperature-dependent shifts of ions along the c axis, we infer a charge transfer of 5-10% of the hole density from the planes to the chains on warming from the superconducting transition to room temperature. Given the significant coupling of c -axis displacements to the average charge density, we point out the relevance of local displacements for screening charge modulations and note recent evidence for dynamic screening of in-plane quasiparticles. This line of argument leads us to a simple model for atomic displacements and charge modulation that is consistent with images from scanning-tunneling microscopy for underdoped Bi2Sr2CaCu2O8 +δ .

  7. Spin liquid phases of large spin Mott insulating ultracold atoms

    NASA Astrophysics Data System (ADS)

    Rutkowski, Todd C.; Lawler, Michael J.

    2015-03-01

    Understanding exotic forms of magnetism, primarily those driven by large spin fluctuations such as the quantum spin liquid state, is a major goal of condensed matter physics. But, the relatively small number of viable candidate materials poses a difficulty. We believe this problem can be solved by Mott insulating ultracold atoms with large spin moments that interact via whole-atom exchange. The large spin fluctuations of this exchange could stabilize exotic physics similar to condensed matter systems, all in an extremely tunable environment. We have approached the problem by performing a mean field theory for spin-f bosons in an optical lattice which is exact in the large-f limit. This setting is similar to that of SU(N) magnetism proposed for alkali-earth atoms but without the SU(N) symmetry. We find that states with long-range order, such as the spin nematic phase of f = 1 Na atoms, become highly entangled spin-liquid-like states for f = 3 Cr atoms. This is evidence that the magnetic phase diagram for Mott insulating atoms at larger spins generically contains exotic forms of magnetism.

  8. Evolution of Rupture Style with Accumulation of Fault Displacement during Large-scale Biaxial Friction Experiments

    NASA Astrophysics Data System (ADS)

    Xu, S.; Fukuyama, E.; Yamashita, F.; Mizoguchi, K.; Takizawa, S.; Kawakata, H.

    2014-12-01

    We report results with Indian Gabbro (Vs=3.62km/s) that are obtained from a series of large-scale biaxial friction experiments conducted at NIED. We focus on strain gage array data of stick-slip events loaded with 0.01mm/s and under 6.7MPa normal stress, and find the following: (1) During early stage when the contact surface is relatively intact, ruptures mainly behave as slow-slip events, with a transition from extremely slow slip (~ 10 m/s) to normal slow slip (~ 100 m/s). (2) With the accumulation of total fault displacement, grooves indicative of locally high normal-stress patches (i.e. asperities) are generated along the sliding surface, which are primarily elongated along the loading direction and are associated with gouge formation. On the other hand, the rest part of the surface continues being polished, indicated by a contrast in light reflectivity with respect to the initial level. At this stage, rupture speeds start to increase but are still well below the shear wave speed (~ 1/4Vs). (3) After long enough total fault displacement (> 500mm), grooves and gouges of a sufficient amount are generated. The following ruptures then show a classic behavior as documented by Ohnaka (2000), which composes of a quasi-static phase, an accelerating phase, and an unstable propagation phase. Although the terminal propagation speed usually reaches a level comparable to the shear wave speed, there is a significant variability for the earlier phases among different events, suggesting that those earlier phases are more sensitive to the evolving local fault structure and/or stress heterogeneity. Further investigation reveals that fault properties (e.g. grooves and gouges) as a function of the accumulated displacement can influence both the macroscopic and the local strain drop, which are most-likely responsible for the evolution of rupture behavior under the same macroscopic loading conditions. We aim to quantify this relation in a continued study.

  9. Large momentum transfer atom interferometry with Coriolis force compensation

    NASA Astrophysics Data System (ADS)

    Kuan, Pei-Chen; Lan, Shau-Yu; Estey, Brian; Haslinger, Philipp; Mueller, Holger

    2012-06-01

    Light-pulse atom interferometers use atom-photon interactions to coherently split, guide, and recombine freely falling matter-waves. Because of Earth's rotation, however, the matter-waves do not recombine precisely, which causes severe loss of contrast in large space-time atom interferometers. I will present our recent progress in using a tip-tilt mirror to remove the influence of the Coriolis force from Earth's rotation. Therefore, we improve the contrast and suppress systematic effects, also reach what is to our knowledge the largest spacetime area.

  10. A versatile MEMS bimorph actuator with large vertical displacement and high resolution: Design and fabrication process

    NASA Astrophysics Data System (ADS)

    Rangra, Aarushee; Maninder, K.; Soni, Shilpi; Rangra, K. J.

    2016-04-01

    This paper presents design, simulation results and envisaged fabrication process for a versatile MEMS bimorph actuator with large out of plane displacement and high resolution. A comparative study of mechanical, thermal and electrical response of the micro-actuator is presented by using two well-known MEMS simulation tools. The bimorph structure measuring 700 × 1280 mm2 is fully integrable with CMOS fabrication process. It is indented for tunable filter applications where the precise vertical motion of the payload, the top metallic electrode anchored rigidly to bimorph `springs' spans the vertical range of 250-300 microns with submicron resolution. Each bimorph spring resembles a hair pin structure and is composed of materials with large difference in thermal expansion coefficients e.g. electroplated gold and polysilicon for optimal out-of-the plane deflection. The novel structure can also be configured for analog micro-mirror based optical and IR spectroscopy applications by controlling the actuation bias and top electrode surface parameters.

  11. A novel large displacement electrostatic actuator: pre-stress comb-drive actuator

    NASA Astrophysics Data System (ADS)

    Chiou, J. C.; Lin, Y. J.

    2005-09-01

    This investigation proposes a novel large vertical displacement electrostatic actuator, called the pre-stress comb-drive actuator (PCA), which exhibits no pull-in and no hysteresis characteristics. The proposed PCA consists of a set of comb fingers fabricated along the composite beam and substrate. One end of the composite beam is clamped to the anchor, whereas the other end is elevated vertically by the residual stress. The actuation occurs when the electrostatic force, induced by the fringe effect, pulls the composite beam downward to the substrate. A post-heat treatment process was employed to increase the initial lift height of the PCA to obtain a large actuation stroke. A mathematical model, based on a newly developed modeling approach, is introduced to estimate the static characteristic of the PCA. A PCA was fabricated using the PolyMUMPs process based on the proposed design concept. Following packaging and applying a post-heat treatment process, a 110 µm initial tip height and a 90 µm vertical motion range were achieved. Neither pull-in nor hysteresis was observed. The simulation results were closely matched with the observations. This work also studies the frequency response and measurement of the maximum vibration of the PCA.

  12. Dynamic modeling of mass-flowing linear medium with large amplitude displacement and rotation

    NASA Astrophysics Data System (ADS)

    Hong, Difeng; Tang, Jiali; Ren, Gexue

    2011-11-01

    In this paper, a dynamic model of a linear medium with mass flow, such as traveling strings, cables, belts, beams or pipes conveying fluids, is proposed, in the framework of Arbitrary-Lagrange-Euler (ALE) description. The material coordinate is introduced to characterize the mass-flow of the medium, and the Absolute Nodal Coordinate Formulation (ANCF) is employed to capture geometric nonlinearity of the linear media under large displacement and rotation. The governing equations are derived in terms of d'Alembert's principle. When using an ALE description, complex mass-flowing boundary conditions can be easily enforced. Numerical examples are presented to validate the proposed method by comparison with analytical results of simplified models. The computed critical fluid velocity for the stability of a cantilevered pipe conveying fluid is correlated with the available theory in literature. The large amplitude limit-cycle oscillations of flexible pipes conveying fluid are presented, and the effect of the velocity of the fluid on the static equilibrium of the pipe under gravity is investigated.

  13. Subpixelic measurement of large 1D displacements: principle, processing algorithms, performances and software.

    PubMed

    Guelpa, Valérian; Laurent, Guillaume J; Sandoz, Patrick; Zea, July Galeano; Clévy, Cédric

    2014-01-01

    This paper presents a visual measurement method able to sense 1D rigid body displacements with very high resolutions, large ranges and high processing rates. Sub-pixelic resolution is obtained thanks to a structured pattern placed on the target. The pattern is made of twin periodic grids with slightly different periods. The periodic frames are suited for Fourier-like phase calculations-leading to high resolution-while the period difference allows the removal of phase ambiguity and thus a high range-to-resolution ratio. The paper presents the measurement principle as well as the processing algorithms (source files are provided as supplementary materials). The theoretical and experimental performances are also discussed. The processing time is around 3 µs for a line of 780 pixels, which means that the measurement rate is mostly limited by the image acquisition frame rate. A 3-σ repeatability of 5 nm is experimentally demonstrated which has to be compared with the 168 µm measurement range. PMID:24625736

  14. An arbitrary Lagrangian-Eulerian formulation for solving moving boundary problems with large displacements and rotations

    NASA Astrophysics Data System (ADS)

    Erzincanli, Belkis; Sahin, Mehmet

    2013-12-01

    An Arbitrary Lagrangian-Eulerian (ALE) formulation based on the unstructured finite volume method is proposed for solving moving boundary problems with large displacements and rotations. The numerical method is based on the side-centered arrangement of the primitive variables that does not require any ad-hoc modifications in order to enhance pressure coupling. The continuity equation is satisfied within each element at machine precision and the summation of the continuity equations can be exactly reduced to the domain boundary, which is important for the global mass conservation. A special attention is given to construct an ALE algorithm obeying the discrete geometric conservation law (DGCL). The mesh deformation algorithm is based on the indirect Radial Basis Function (RBF) algorithm at each time level while avoiding remeshing in order to enhance numerical robustness. For the parallel solution of resulting large-scale algebraic equations in a fully coupled form, a matrix factorization is introduced similar to that of the projection method for the whole system and the parallel algebraic multigrid solver BoomerAMG is used for the scaled discrete Laplacian provided by the HYPRE library which we access through the PETSc library. The present numerical algorithm is initially validated for the decaying Taylor-Green vortex flow, the flow past an oscillating circular cylinder in a channel and the flow induced by an oscillating sphere in a cubic cavity. Then the numerical algorithm is applied to the numerical simulation of flow field around a pair of flapping Drosophila wings in hover flight. The time variation of the Eulerian coherent structures in the near wake is shown along with the aerodynamic loads.

  15. Displacement, county social cohesion and depression after a large-scale traumatic event

    PubMed Central

    Lê, Félice; Tracy, Melissa; Norris, Fran H.; Galea, Sandro

    2013-01-01

    Background Depression is a common and potentially debilitating consequence of traumatic events. Mass traumatic events cause wide-ranging disruptions to community characteristics, influencing the population risk of depression. In the aftermath of such events, population displacement is common. Stressors associated with displacement may increase risk of depression directly. Indirectly, persons who are displaced may experience erosion in social cohesion, further exacerbating their risk for depression. Methods Using data from a population-based cross-sectional survey of adults living in the 23 southernmost counties of Mississippi (N = 708), we modeled the independent and joint relations of displacement and county-level social cohesion with depression 18–24 months after Hurricane Katrina. Results After adjustment for individual- and county-level sociodemographic characteristics and county-level hurricane exposure, joint exposure to both displacement and low social cohesion was associated with substantially higher log-odds of depression (b = 1.34 [0.86–1.83]). Associations were much weaker for exposure only to low social cohesion (b = 0.28 [−0.35–0.90]) or only to displacement (b = 0.04 [−0.80– 0.88]). The associations were robust to additional adjustment for individually perceived social cohesion and social support. Conclusion Addressing the multiple, simultaneous disruptions that are a hallmark of mass traumatic events is important to identify vulnerable populations and understand the psychological ramifications of these events. PMID:23644724

  16. Dynamic displacement measurement of large-scale structures based on the Lucas-Kanade template tracking algorithm

    NASA Astrophysics Data System (ADS)

    Guo, Jie; Zhu, Chang`an

    2016-01-01

    The development of optics and computer technologies enables the application of the vision-based technique that uses digital cameras to the displacement measurement of large-scale structures. Compared with traditional contact measurements, vision-based technique allows for remote measurement, has a non-intrusive characteristic, and does not necessitate mass introduction. In this study, a high-speed camera system is developed to complete the displacement measurement in real time. The system consists of a high-speed camera and a notebook computer. The high-speed camera can capture images at a speed of hundreds of frames per second. To process the captured images in computer, the Lucas-Kanade template tracking algorithm in the field of computer vision is introduced. Additionally, a modified inverse compositional algorithm is proposed to reduce the computing time of the original algorithm and improve the efficiency further. The modified algorithm can rapidly accomplish one displacement extraction within 1 ms without having to install any pre-designed target panel onto the structures in advance. The accuracy and the efficiency of the system in the remote measurement of dynamic displacement are demonstrated in the experiments on motion platform and sound barrier on suspension viaduct. Experimental results show that the proposed algorithm can extract accurate displacement signal and accomplish the vibration measurement of large-scale structures.

  17. The impact of short-range forces on high-energy atom collisions in displacement cascades

    NASA Astrophysics Data System (ADS)

    Samolyuk, German; Stoller, Roger; Tamm, Artur; Beland, Laurent; Stocks, G. Malcolm; Caro, Alfredo; Slipchenko4, Lyudmila; Osetskiy, Yury; Aabloo, Alvo; Klintenberg, Mattias; Wang, Yang

    Simulation of primary radiation damage formation in solid materials involves collisions between atoms with a few hundred keV of kinetic energy. As a result, during these collisions, the distance between two colliding atoms can approach 0.05 nm. For such small atomic separations, interatomic potentials significantly underestimate the potential energy. The common practice involves using a screened Coulomb pair potential to describe the high-energy interactions and to smoothly join this to the equilibrium potential. However, there is no standard method for choosing the joining parameters and defect production during cascade evolution has been shown to be sensitive to how the joining is done. We developed a new procedure, which includes the use of ab initio, calculations to determine the pair interactions at intermediate distances, together with systematic criteria for choosing the joining parameters. Results are presented for the case of nickel. Research at the Oak Ridge National Laboratory and Los Alamos National Laboratory sponsored by the U.S. Department of Energy, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, ``Center for Energy Dissipation to Defect Evolution''.

  18. Subradiance in a Large Cloud of Cold Atoms

    NASA Astrophysics Data System (ADS)

    Guerin, William; Araújo, Michelle O.; Kaiser, Robin

    2016-02-01

    Since Dicke's seminal paper on coherence in spontaneous radiation by atomic ensembles, superradiance has been extensively studied. Subradiance, on the contrary, has remained elusive, mainly because subradiant states are weakly coupled to the environment and are very sensitive to nonradiative decoherence processes. Here, we report the experimental observation of subradiance in an extended and dilute cold-atom sample containing a large number of particles. We use a far detuned laser to avoid multiple scattering and observe the temporal decay after a sudden switch-off of the laser beam. After the fast decay of most of the fluorescence, we detect a very slow decay, with time constants as long as 100 times the natural lifetime of the excited state of individual atoms. This subradiant time constant scales linearly with the cooperativity parameter, corresponding to the on-resonance optical depth of the sample, and is independent of the laser detuning, as expected from a coupled-dipole model.

  19. One-step displacement dispersive liquid-liquid microextraction coupled with graphite furnace atomic absorption spectrometry for the selective determination of methylmercury in environmental samples.

    PubMed

    Liang, Pei; Kang, Caiyan; Mo, Yajun

    2016-03-01

    A novel method for the selective determination of methylmercury (MeHg) was developed by one-step displacement dispersive liquid-liquid microextraction (D-DLLME) coupled with graphite furnace atomic absorption spectrometry. In the proposed method, Cu(II) reacted with diethyldithiocarbamate (DDTC) to form Cu-DDTC complex, which was used as the chelating agent instead of DDTC for the dispersive liquid-liquid microextraction (DLLME) of MeHg. Because the stability of MeHg-DDTC is higher than that of Cu-DDTC, MeHg can displace Cu from the Cu-DDTC complex and be preconcentrated in a single DLLME procedure. MeHg could be extracted into the extraction solvent phase at pH 6 while Hg(II) remained in the sample solution. Potential interference from co-existing metal ions with lower DDTC complex stability was largely eliminated without the need of any masking reagent. Under the optimal conditions, the limit of detection of this method was 13.6ngL(-1) (as Hg), and an enhancement factor of 81 was achieved with a sample volume of 5.0mL. The proposed method was successfully applied for the determination of trace MeHg in some environmental samples with satisfactory results. PMID:26717807

  20. Detection of atomic force microscopy cantilever displacement with a transmitted electron beam

    NASA Astrophysics Data System (ADS)

    Wagner, R.; Woehl, T. J.; Keller, R. R.; Killgore, J. P.

    2016-07-01

    The response time of an atomic force microscopy (AFM) cantilever can be decreased by reducing cantilever size; however, the fastest AFM cantilevers are currently nearing the smallest size that can be detected with the conventional optical lever approach. Here, we demonstrate an electron beam detection scheme for measuring AFM cantilever oscillations. The oscillating AFM tip is positioned perpendicular to and in the path of a stationary focused nanometer sized electron beam. As the tip oscillates, the thickness of the material under the electron beam changes, causing a fluctuation in the number of scattered transmitted electrons that are detected. We demonstrate detection of sub-nanometer vibration amplitudes with an electron beam, providing a pathway for dynamic AFM with cantilevers that are orders of magnitude smaller and faster than the current state of the art.

  1. Measurement of transient atomic displacements in thin films with picosecond and femtometer resolution

    PubMed Central

    Kozina, M.; Hu, T.; Wittenberg, J. S.; Szilagyi, E.; Trigo, M.; Miller, T. A.; Uher, C.; Damodaran, A.; Martin, L.; Mehta, A.; Corbett, J.; Safranek, J.; Reis, D. A.; Lindenberg, A. M.

    2014-01-01

    We report measurements of the transient structural response of weakly photo-excited thin films of BiFeO3, Pb(Zr,Ti)O3, and Bi and time-scales for interfacial thermal transport. Utilizing picosecond x-ray diffraction at a 1.28 MHz repetition rate with time resolution extending down to 15 ps, transient changes in the diffraction angle are recorded. These changes are associated with photo-induced lattice strains within nanolayer thin films, resolved at the part-per-million level, corresponding to a shift in the scattering angle three orders of magnitude smaller than the rocking curve width and changes in the interlayer lattice spacing of fractions of a femtometer. The combination of high brightness, repetition rate, and stability of the synchrotron, in conjunction with high time resolution, represents a novel means to probe atomic-scale, near-equilibrium dynamics. PMID:26798776

  2. Measurement of transient atomic displacements in thin films with picosecond and femtometer resolution.

    PubMed

    Kozina, M; Hu, T; Wittenberg, J S; Szilagyi, E; Trigo, M; Miller, T A; Uher, C; Damodaran, A; Martin, L; Mehta, A; Corbett, J; Safranek, J; Reis, D A; Lindenberg, A M

    2014-05-01

    We report measurements of the transient structural response of weakly photo-excited thin films of BiFeO3, Pb(Zr,Ti)O3, and Bi and time-scales for interfacial thermal transport. Utilizing picosecond x-ray diffraction at a 1.28 MHz repetition rate with time resolution extending down to 15 ps, transient changes in the diffraction angle are recorded. These changes are associated with photo-induced lattice strains within nanolayer thin films, resolved at the part-per-million level, corresponding to a shift in the scattering angle three orders of magnitude smaller than the rocking curve width and changes in the interlayer lattice spacing of fractions of a femtometer. The combination of high brightness, repetition rate, and stability of the synchrotron, in conjunction with high time resolution, represents a novel means to probe atomic-scale, near-equilibrium dynamics. PMID:26798776

  3. Molecular dynamics modeling of atomic displacement cascades in 3C-SiC: Comparison of interatomic potentials

    SciTech Connect

    Samolyuk, German D.; Osetskiy, Yury N.; Stoller, Roger E.

    2015-06-03

    We used molecular dynamics modeling of atomic displacement cascades to characterize the nature of primary radiation damage in 3C-SiC. We demonstrated that the most commonly used interatomic potentials are inconsistent with ab initio calculations of defect energetics. Both the Tersoff potential used in this work and a modified embedded-atom method potential reveal a barrier to recombination of the carbon interstitial and carbon vacancy which is much higher than the density functional theory (DFT) results. The barrier obtained with a newer potential by Gao and Weber is closer to the DFT result. This difference results in significant differences in the cascade production of point defects. We have completed both 10 keV and 50 keV cascade simulations in 3C-SiC at a range of temperatures. In contrast to the Tersoff potential, the Gao-Weber potential produces almost twice as many C vacancies and interstitials at the time of maximum disorder (~0.2 ps) but only about 25% more stable defects at the end of the simulation. Only about 20% of the carbon defects produced with the Tersoff potential recombine during the in-cascade annealing phase, while about 60% recombine with the Gao-Weber potential.

  4. Molecular dynamics modeling of atomic displacement cascades in 3C-SiC: Comparison of interatomic potentials

    NASA Astrophysics Data System (ADS)

    Samolyuk, G. D.; Osetsky, Y. N.; Stoller, R. E.

    2015-10-01

    We used molecular dynamics modeling of atomic displacement cascades to characterize the nature of primary radiation damage in 3C-SiC. We demonstrated that the most commonly used interatomic potentials are inconsistent with ab initio calculations of defect energetics. Both the Tersoff potential used in this work and a modified embedded-atom method potential reveal a barrier to recombination of the carbon interstitial and carbon vacancy which is much higher than the density functional theory (DFT) results. The barrier obtained with a newer potential by Gao and Weber is closer to the DFT result. This difference results in significant differences in the cascade production of point defects. We have completed both 10 keV and 50 keV cascade simulations in 3C-SiC at a range of temperatures. In contrast to the Tersoff potential, the Gao-Weber potential produces almost twice as many C vacancies and interstitials at the time of maximum disorder (∼0.2 ps) but only about 25% more stable defects at the end of the simulation. Only about 20% of the carbon defects produced with the Tersoff potential recombine during the in-cascade annealing phase, while about 60% recombine with the Gao-Weber potential. The Gao-Weber potential appears to give a more realistic description of cascade dynamics in SiC, but still has some shortcomings when the defect migration barriers are compared to the ab initio results.

  5. Molecular dynamics modeling of atomic displacement cascades in 3C-SiC: Comparison of interatomic potentials

    DOE PAGESBeta

    Samolyuk, German D.; Osetskiy, Yury N.; Stoller, Roger E.

    2015-06-03

    We used molecular dynamics modeling of atomic displacement cascades to characterize the nature of primary radiation damage in 3C-SiC. We demonstrated that the most commonly used interatomic potentials are inconsistent with ab initio calculations of defect energetics. Both the Tersoff potential used in this work and a modified embedded-atom method potential reveal a barrier to recombination of the carbon interstitial and carbon vacancy which is much higher than the density functional theory (DFT) results. The barrier obtained with a newer potential by Gao and Weber is closer to the DFT result. This difference results in significant differences in the cascademore » production of point defects. We have completed both 10 keV and 50 keV cascade simulations in 3C-SiC at a range of temperatures. In contrast to the Tersoff potential, the Gao-Weber potential produces almost twice as many C vacancies and interstitials at the time of maximum disorder (~0.2 ps) but only about 25% more stable defects at the end of the simulation. Only about 20% of the carbon defects produced with the Tersoff potential recombine during the in-cascade annealing phase, while about 60% recombine with the Gao-Weber potential.« less

  6. Large-angle illumination STEM: Toward three-dimensional atom-by-atom imaging

    SciTech Connect

    Ishikawa, Ryo; Lupini, Andrew R.; Hinuma, Yoyo; Pennycook, Stephen

    2014-11-26

    To completely understand and control materials and their properties, it is of critical importance to determine their atomic structures in all three dimensions. Recent revolutionary advances in electron optics – the inventions of geometric and chromatic aberration correctors as well as electron source monochromators – have provided fertile ground for performing optical depth sectioning at atomic-scale dimensions. In this study we theoretically demonstrate the imaging of top/sub-surface atomic structures and identify the depth of single dopants, single vacancies and the other point defects within materials by large-angle illumination scanning transmission electron microscopy (LAI-STEM). The proposed method also allows us to measure specimen properties such as thickness or three-dimensional surface morphology using observations from a single crystallographic orientation.

  7. Large-angle illumination STEM: Toward three-dimensional atom-by-atom imaging

    DOE PAGESBeta

    Ishikawa, Ryo; Lupini, Andrew R.; Hinuma, Yoyo; Pennycook, Stephen

    2014-11-26

    To completely understand and control materials and their properties, it is of critical importance to determine their atomic structures in all three dimensions. Recent revolutionary advances in electron optics – the inventions of geometric and chromatic aberration correctors as well as electron source monochromators – have provided fertile ground for performing optical depth sectioning at atomic-scale dimensions. In this study we theoretically demonstrate the imaging of top/sub-surface atomic structures and identify the depth of single dopants, single vacancies and the other point defects within materials by large-angle illumination scanning transmission electron microscopy (LAI-STEM). The proposed method also allows us tomore » measure specimen properties such as thickness or three-dimensional surface morphology using observations from a single crystallographic orientation.« less

  8. Application of proving-ring technology to measure thermally induced displacements in large boreholes in rock

    SciTech Connect

    Patrick, W.C.; Reactor, N.L.; Butkovich, T.R.

    1984-03-01

    A strain-gauged proving-ring transducer was designed and deployed to measure small diametral displacements in 0.61-m diameter boreholes in rock. The rock surrounding the boreholes was previously heated by storage of spent nuclear fuel assemblies and measurements during post-retrieval cooling of the rock were made. To accomplish this, a transducer was designed to measure displacements in the range of 10 to 100 {mu}m, to function in a time-varying temperature regime of 30{sup 0} to 60{sup 0}C at a relative humidity of 100%, to be of low stiffness, and to be easily and quickly installed. 7 references, 6 figures, 1 table.

  9. Energetics of Li atom displacements in K1-xLixTaO3: First-principles calculations

    NASA Astrophysics Data System (ADS)

    Prosandeev, S. A.; Cockayne, E.; Burton, B. P.

    2003-07-01

    K1-xLixTaO3 (KLT) solid solutions exhibit a variety of interesting physical phenomena related to large displacements of Li-ions from ideal perovskite A-site positions. First-principles calculations for KLT supercells were used to investigate these phenomena. Lattice dynamics calculations for KLT exhibit a Li off-centering instability. The energetics of Li-displacements for isolated Li-ions and for Li-Li pairs up to 4th neighbors were calculated. Interactions between nearest neighbor Li-ions, in a Li-Li pair, strongly favor ferroelectric alignment along the pair axis. Such Li-Li pairs can be considered “seeds” for polar nanoclusters in KLT. Electrostriction, local oxygen relaxation, coupling to the KT soft-mode, and interactions with neighboring Li ions all enhance the polarization from Li off-centering. Calculated hopping barriers for isolated Li ions and for nearest neighbor Li-Li pairs are in good agreement with Arrhenius fits to experimental dielectric data.

  10. Observation of an unusually large atomic parity-violation effect

    NASA Astrophysics Data System (ADS)

    Tsigutkin, Konstantin

    2010-03-01

    We report on observation of a large parity-violation effect in the atoms of ytterbium (Yb). This left-right asymmetry appears naturally in the Standard Model, and is associated with the exchange of a virtual heavy ``gauge" boson between subatomic particles. Eventually, parity violation has been observed and precisely measured by a number of groups in several different atoms, culminating in a 0.3% measurement in cesium (Cs) by Carl Wieman and co-workers at Boulder. The parity-violating amplitude of the 6x^2 ^1S0 -> 5d6s ^3D1 408-nm forbidden transition of ytterbium is found to be two orders of magnitude larger than in cesium. This is the largest atomic parity-violating amplitude yet observed. This also opens the way to future measurements of the parity violation effects for different Yb isotopes in order to test the effect of the neutron distributions within the nucleus and detect the so-called ``anapole moment" by comparing parity-violating amplitudes for various hyperfine components of the transition. So far, Cs is the only system where such a moment has been detected. Measurements of anapole moments are important for understanding the electroweak interactions within the nucleus which are hard to probe by other means.

  11. Studying Displacement After a Disaster Using Large Scale Survey Methods: Sumatra After the 2004 Tsunami

    PubMed Central

    Gray, Clark; Frankenberg, Elizabeth; Gillespie, Thomas; Sumantri, Cecep; Thomas, Duncan

    2014-01-01

    Understanding of human vulnerability to environmental change has advanced in recent years, but measuring vulnerability and interpreting mobility across many sites differentially affected by change remains a significant challenge. Drawing on longitudinal data collected on the same respondents who were living in coastal areas of Indonesia before the 2004 Indian Ocean tsunami and were re-interviewed after the tsunami, this paper illustrates how the combination of population-based survey methods, satellite imagery and multivariate statistical analyses has the potential to provide new insights into vulnerability, mobility and impacts of major disasters on population well-being. The data are used to map and analyze vulnerability to post-tsunami displacement across the provinces of Aceh and North Sumatra and to compare patterns of migration after the tsunami between damaged areas and areas not directly affected by the tsunami. The comparison reveals that migration after a disaster is less selective overall than migration in other contexts. Gender and age, for example, are strong predictors of moving from undamaged areas but are not related to displacement in areas experiencing damage. In our analyses traditional predictors of vulnerability do not always operate in expected directions. Low levels of socioeconomic status and education were not predictive of moving after the tsunami, although for those who did move, they were predictive of displacement to a camp rather than a private home. This survey-based approach, though not without difficulties, is broadly applicable to many topics in human-environment research, and potentially opens the door to rigorous testing of new hypotheses in this literature. PMID:24839300

  12. Fast figuring of large optics by reactive atom plasma

    NASA Astrophysics Data System (ADS)

    Castelli, Marco; Jourdain, Renaud; Morantz, Paul; Shore, Paul

    2012-09-01

    The next generation of ground-based astronomical observatories will require fabrication and maintenance of extremely large segmented mirrors tens of meters in diameter. At present, the large production of segments required by projects like E-ELT and TMT poses time frames and costs feasibility questions. This is principally due to a bottleneck stage in the optical fabrication chain: the final figuring step. State-of-the-art figure correction techniques, so far, have failed to meet the needs of the astronomical community for mass production of large, ultra-precise optical surfaces. In this context, Reactive Atom Plasma (RAP) is proposed as a candidate figuring process that combines nanometer level accuracy with high material removal rates. RAP is a form of plasma enhanced chemical etching at atmospheric pressure based on Inductively Coupled Plasma technology. The rapid figuring capability of the RAP process has already been proven on medium sized optical surfaces made of silicon based materials. In this paper, the figure correction of a 3 meters radius of curvature, 400 mm diameter spherical ULE mirror is presented. This work demonstrates the large scale figuring capability of the Reactive Atom Plasma process. The figuring is carried out by applying an in-house developed procedure that promotes rapid convergence. A 2.3 μm p-v initial figure error is removed within three iterations, for a total processing time of 2.5 hours. The same surface is then re-polished and the residual error corrected again down to λ/20 nm rms. These results highlight the possibility of figuring a metre-class mirror in about ten hours.

  13. Adjusting and positioning method with high displacement resolution for large-load worktable based on the invariable restoring force

    NASA Astrophysics Data System (ADS)

    Huang, Jingzhi; Sun, Tao; Gu, Wei; Wen, Zhongpu; Guo, Tenghui

    2015-02-01

    With the fast development of the advanced equipment manufacturing toward precision and ultra-precision trend, especially with the continuously improving of the aviation engine's performance, the problem of high displacement resolution for the large-load two-dimension adjusting and positioning worktable used for the aeroengine assembling become evident. A method was proposed which is based on the invariable restoring force, and the adjusting and positioning physical model was established. The experiment results indicate that under the occasion of a load with 508 kilogram, the worktable has got a displacement resolution of 0.3μm after using the improved method compared to 1.4μm of the traditional method. The improved method could meet the requirements of aviation engine assembling worktable.

  14. Fabry-Perot interferometer utilized for displacement measurement in a large measuring range

    SciTech Connect

    Wang, Yung-Cheng; Shyu, Lih-Horng; Chang, Chung-Ping

    2010-09-15

    The optical configuration of a Fabry-Perot interferometer is uncomplicated. This has already been applied in different measurement systems. For the displacement measurement with the Fabry-Perot interferometer, the result is significantly influenced by the tilt angles of the measurement mirror in the interferometer. Hence, only for the rather small measuring range, the Fabry-Perot interferometer is available. The goal of this investigation is to enhance the measuring range of Fabry-Perot interferometer by compensating the tilt angles. To verify the measuring characteristic of the self-developed Fabry-Perot interferometer, some comparison measurements with a reference standard have been performed. The maximum deviation of comparison experiments is less than 0.3 {mu}m in the traveling range of 30 mm. The experimental results show that the Fabry-Perot interferometer is highly stable, insensitive to environment effects, and can meet the measuring requirement of the submicrometer order.

  15. Determination of the shear buckling load of a large polymer composite I-section using strain and displacement sensors.

    PubMed

    Park, Jin Y; Lee, Jeong Wan

    2012-01-01

    This paper presents a method and procedure of sensing and determining critical shear buckling load and corresponding deformations of a comparably large composite I-section using strain rosettes and displacement sensors. The tested specimen was a pultruded composite beam made of vinyl ester resin, E-glass and carbon fibers. Various coupon tests were performed before the shear buckling test to obtain fundamental material properties of the I-section. In order to sensitively detect shear buckling of the tested I-section, twenty strain rosettes and eight displacement sensors were applied and attached on the web and flange surfaces. An asymmetric four-point bending loading scheme was utilized for the test. The loading scheme resulted a high shear and almost zero moment condition at the center of the web panel. The web shear buckling load was determined after analyzing the obtained test data from strain rosettes and displacement sensors. Finite element analysis was also performed to verify the experimental results and to support the discussed experimental approach. PMID:23443364

  16. Noise-Immune Conjugate Large-Area Atom Interferometers

    SciTech Connect

    Chiow Shengwey; Herrmann, Sven; Chu, Steven; Mueller, Holger

    2009-07-31

    We present a pair of simultaneous conjugate Ramsey-Borde atom interferometers using large (20(Planck constant/2pi)k)-momentum transfer beam splitters, where (Planck constant/2pi)k is the photon momentum. Simultaneous operation allows for common-mode rejection of vibrational noise. This allows us to surpass the enclosed space-time area of previous interferometers with a splitting of 20(Planck constant/2pi)k by a factor of 2500. Using a splitting of 10(Planck constant/2pi)k, we demonstrate a 3.4 ppb resolution in the measurement of the fine structure constant. Examples for applications in tests of fundamental laws of physics are given.

  17. Long term simulation of point defect cluster size distributions from atomic displacement cascades in Fe70Cr20Ni10

    NASA Astrophysics Data System (ADS)

    Souidi, A.; Hou, M.; Becquart, C. S.; Domain, C.; De Backer, A.

    2015-06-01

    We have used an Object Kinetic Monte Carlo (OKMC) model to simulate the long term evolution of the primary damage in Fe70Cr20Ni10 alloys. The mean number of Frenkel pairs created by different Primary Knocked on Atoms (PKA) was estimated by Molecular Dynamics using a ternary EAM potential developed in the framework of the PERFORM-60 European project. This number was then used to obtain the vacancy-interstitial recombination distance required in the calculation of displacement cascades in the Binary Collision Approximation (BCA) with code MARLOWE (Robinson, 1989). The BCA cascades have been generated in the 10-100 keV range with the MARLOWE code and two different screened Coulomb potentials, namely, the Molière approximation to the Thomas-Fermi potential and the so-called "Universal" potential by Ziegler, Biersack and Littmark (ZBL). These cascades have been used as input to the OKMC code LAKIMOCA (Domain et al., 2004), with a set of parameters for describing the mobility of point defect clusters based on ab initio calculations and experimental data. The cluster size distributions have been estimated for irradiation doses of 0.1 and 1 dpa, and a dose rate of 10-7 dpa/s at 600 K. We demonstrate that, like in the case of BCC iron, cluster size distributions in the long term are independent of the cascade energy and that the recursive cascade model suggested for BCC iron in Souidi et al. (2011) also applies to FCC Fe70Cr20Ni10. The results also show that the influence of the BCA potential is sizeable but the qualitative correspondence in the predicted long term evolution is excellent.

  18. Large-scale separation of amino acids by continuous displacement chromatography

    SciTech Connect

    DeCarli, J.P. II; Carta, G.; Byers, C.H.

    1989-10-01

    Continuous annular chromatography (CAC) is a developing technology that allows truly continuous chromatographic separations. Previous work has demonstrated the utility of this technology for the separation of various materials by isocratic elution on a bench scale. Novel applications and improved operation of the process were studied in this work, demonstrating that CAC is a versatile apparatus which is capable of separations at high throughput. Three specific separation systems were investigated. Pilot-scale separations at high loadings were performed using an industrial sugar mixture as an example of scale-up for isocratic separations. Bench-scale experiments of a low concentration metal ion mixture were performed to demonstrate stepwise elution, a chromatographic technique which decreases dilution and increases sorbent capacity. Finally, the separation of mixtures of amino acids by ion exchange was investigated to demonstrate the use of displacement development on the CAC. This technique, which perhaps has the most potential, when applied to the CAC allowed simultaneous separation and concentration of multicomponent mixtures on a continuous basis. Mathematical models were developed to describe the CAC performance and optimize the operating conditions. For all the systems investigated, the continuous separation performance of the CAC was found to be very nearly the same as the batchwise performance of conventional chromatography. The technology appears, thus, to be very promising for industrial applications.

  19. Search for displaced supersymmetry in events with an electron and a muon with large impact parameters.

    PubMed

    Khachatryan, V; Sirunyan, A M; Tumasyan, A; Adam, W; Bergauer, T; Dragicevic, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hartl, C; Hörmann, N; Hrubec, J; Jeitler, M; Kiesenhofer, W; Knünz, V; Krammer, M; Krätschmer, I; Liko, D; Mikulec, I; Rabady, D; Rahbaran, B; Rohringer, H; Schöfbeck, R; Strauss, J; Taurok, A; Treberer-Treberspurg, W; Waltenberger, W; Wulz, C-E; Mossolov, V; Shumeiko, N; Suarez Gonzalez, J; Alderweireldt, S; Bansal, M; Bansal, S; Cornelis, T; De Wolf, E A; Janssen, X; Knutsson, A; Luyckx, S; Ochesanu, S; Rougny, R; Van De Klundert, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Van Spilbeeck, A; Blekman, F; Blyweert, S; D'Hondt, J; Daci, N; Heracleous, N; Keaveney, J; Lowette, S; Maes, M; Olbrechts, A; Python, Q; Strom, D; Tavernier, S; Van Doninck, W; Van Mulders, P; Van Onsem, G P; Villella, I; Caillol, C; Clerbaux, B; De Lentdecker, G; Dobur, D; Favart, L; Gay, A P R; Grebenyuk, A; Léonard, A; Mohammadi, A; Perniè, L; Reis, T; Seva, T; Thomas, L; Vander Velde, C; Vanlaer, P; Wang, J; Zenoni, F; Adler, V; Beernaert, K; Benucci, L; Cimmino, A; Costantini, S; Crucy, S; Dildick, S; Fagot, A; Garcia, G; Mccartin, J; Ocampo Rios, A A; Ryckbosch, D; Salva Diblen, S; Sigamani, M; Strobbe, N; Thyssen, F; Tytgat, M; Yazgan, E; Zaganidis, N; Basegmez, S; Beluffi, C; Bruno, G; Castello, R; Caudron, A; Ceard, L; Da Silveira, G G; Delaere, C; du Pree, T; Favart, D; Forthomme, L; Giammanco, A; Hollar, J; Jafari, A; Jez, P; Komm, M; Lemaitre, V; Nuttens, C; Pagano, D; Perrini, L; Pin, A; Piotrzkowski, K; Popov, A; Quertenmont, L; Selvaggi, M; Vidal Marono, M; Vizan Garcia, J M; Beliy, N; Caebergs, T; Daubie, E; Hammad, G H; Aldá Júnior, W L; Alves, G A; Brito, L; Correa Martins Junior, M; Dos Reis Martins, T; Mora Herrera, C; Pol, M E; Carvalho, W; Chinellato, J; Custódio, A; Da Costa, E M; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Malbouisson, H; Matos Figueiredo, D; Mundim, L; Nogima, H; Prado Da Silva, W L; Santaolalla, J; Santoro, A; Sznajder, A; Tonelli Manganote, E J; Vilela Pereira, A; Bernardes, C A; Dogra, S; Fernandez Perez Tomei, T R; Gregores, E M; Mercadante, P G; Novaes, S F; Padula, Sandra S; Aleksandrov, A; Genchev, V; Iaydjiev, P; Marinov, A; Piperov, S; Rodozov, M; Stoykova, S; Sultanov, G; Vutova, M; Dimitrov, A; Glushkov, I; Hadjiiska, R; Kozhuharov, V; Litov, L; Pavlov, B; Petkov, P; Bian, J G; Chen, G M; Chen, H S; Chen, M; Du, R; Jiang, C H; Plestina, R; Romeo, F; Tao, J; Wang, Z; Asawatangtrakuldee, C; Ban, Y; Liu, S; Mao, Y; Qian, S J; Wang, D; Zhang, L; Zou, W; Avila, C; Chaparro Sierra, L F; Florez, C; Gomez, J P; Gomez Moreno, B; Sanabria, J C; Godinovic, N; Lelas, D; Polic, D; Puljak, I; Antunovic, Z; Kovac, M; Brigljevic, V; Kadija, K; Luetic, J; Mekterovic, D; Sudic, L; Attikis, A; Mavromanolakis, G; Mousa, J; Nicolaou, C; Ptochos, F; Razis, P A; Bodlak, M; Finger, M; Finger, M; Assran, Y; Ellithi Kamel, A; Mahmoud, M A; Radi, A; Kadastik, M; Murumaa, M; Raidal, M; Tiko, A; Eerola, P; Fedi, G; Voutilainen, M; Härkönen, J; Karimäki, V; Kinnunen, R; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Peltola, T; Tuominen, E; Tuominiemi, J; Tuovinen, E; Wendland, L; Talvitie, J; Tuuva, T; Besancon, M; Couderc, F; Dejardin, M; Denegri, D; Fabbro, B; Faure, J L; Favaro, C; Ferri, F; Ganjour, S; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Locci, E; Malcles, J; Rander, J; Rosowsky, A; Titov, M; Baffioni, S; Beaudette, F; Busson, P; Charlot, C; Dahms, T; Dalchenko, M; Dobrzynski, L; Filipovic, N; Florent, A; Granier de Cassagnac, R; Mastrolorenzo, L; Miné, P; Mironov, C; Naranjo, I N; Nguyen, M; Ochando, C; Paganini, P; Regnard, S; Salerno, R; Sauvan, J B; Sirois, Y; Veelken, C; Yilmaz, Y; Zabi, A; Agram, J-L; Andrea, J; Aubin, A; Bloch, D; Brom, J-M; Chabert, E C; Collard, C; Conte, E; Fontaine, J-C; Gelé, D; Goerlach, U; Goetzmann, C; Le Bihan, A-C; Van Hove, P; Gadrat, S; Beauceron, S; Beaupere, N; Boudoul, G; Bouvier, E; Brochet, S; Carrillo Montoya, C A; Chasserat, J; Chierici, R; Contardo, D; Depasse, P; El Mamouni, H; Fan, J; Fay, J; Gascon, S; Gouzevitch, M; Ille, B; Kurca, T; Lethuillier, M; Mirabito, L; Perries, S; Ruiz Alvarez, J D; Sabes, D; Sgandurra, L; Sordini, V; Vander Donckt, M; Verdier, P; Viret, S; Xiao, H; Tsamalaidze, Z; Autermann, C; Beranek, S; Bontenackels, M; Edelhoff, M; Feld, L; Hindrichs, O; Klein, K; Ostapchuk, A; Perieanu, A; Raupach, F; Sammet, J; Schael, S; Weber, H; Wittmer, B; Zhukov, V; Ata, M; Brodski, M; Dietz-Laursonn, E; Duchardt, D; Erdmann, M; Fischer, R; Güth, A; Hebbeker, T; Heidemann, C; Hoepfner, K; Klingebiel, D; Knutzen, S; Kreuzer, P; Merschmeyer, M; Meyer, A; Millet, P; Olschewski, M; Padeken, K; Papacz, P; Reithler, H; Schmitz, S A; Sonnenschein, L

    2015-02-13

    A search for new long-lived particles decaying to leptons is presented using proton-proton collisions produced by the LHC at √[s]=8  TeV. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.7  fb(-1). Events are selected with an electron and muon with opposite charges that both have transverse impact parameter values between 0.02 and 2 cm. The search has been designed to be sensitive to a wide range of models with nonprompt e-μ final states. Limits are set on the "displaced supersymmetry" model, with pair production of top squarks decaying into an e-μ final state via R-parity-violating interactions. The results are the most restrictive to date on this model, with the most stringent limit being obtained for a top squark lifetime corresponding to cτ=2  cm, excluding masses below 790 GeV at 95% confidence level. PMID:25723204

  20. Search for Displaced Supersymmetry in Events with an Electron and a Muon with Large Impact Parameters

    SciTech Connect

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C. -E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Bansal, M.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Knutsson, A.; Luyckx, S.; Ochesanu, S.; Rougny, R.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D’Hondt, J.; Daci, N.; Heracleous, N.; Keaveney, J.; Lowette, S.; Maes, M.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Dobur, D.; Favart, L.; Gay, A. P. R.; Grebenyuk, A.; Léonard, A.; Mohammadi, A.; Perniè, L.; Reis, T.; Seva, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Zenoni, F.; Adler, V.; Beernaert, K.; Benucci, L.; Cimmino, A.; Costantini, S.; Crucy, S.; Dildick, S.; Fagot, A.; Garcia, G.; Mccartin, J.; Ocampo Rios, A. A.; Ryckbosch, D.; Salva Diblen, S.; Sigamani, M.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bruno, G.; Castello, R.; Caudron, A.; Ceard, L.; Da Silveira, G. G.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Nuttens, C.; Pagano, D.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Dos Reis Martins, T.; Mora Herrera, C.; Pol, M. E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Malbouisson, H.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santaolalla, J.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Bernardes, C. A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Aleksandrov, A.; Genchev, V.; Iaydjiev, P.; Marinov, A.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Du, R.; Jiang, C. H.; Plestina, R.; Romeo, F.; Tao, J.; Wang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Zhang, L.; Zou, W.; Avila, C.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Mekterovic, D.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Bodlak, M.; Finger, M.; Finger, M.; Assran, Y.; Ellithi Kamel, A.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Kortelainen, M. J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Baffioni, S.; Beaudette, F.; Busson, P.; Charlot, C.; Dahms, T.; Dalchenko, M.; Dobrzynski, L.; Filipovic, N.; Florent, A.; Granier de Cassagnac, R.; Mastrolorenzo, L.; Miné, P.; Mironov, C.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Paganini, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Veelken, C.; Yilmaz, Y.; Zabi, A.; Agram, J. -L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J. -M.; Chabert, E. C.; Collard, C.; Conte, E.; Fontaine, J. -C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A. -C.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Beaupere, N.; Boudoul, G.; Bouvier, E.; Brochet, S.; Carrillo Montoya, C. A.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Ruiz Alvarez, J. D.; Sabes, D.; Sgandurra, L.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Xiao, H.; Tsamalaidze, Z.; Autermann, C.

    2015-02-01

    A search for new long-lived particles decaying to leptons is presented using proton-proton collisions produced by the LHC at √s=8 TeV. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.7 fb-1. Events are selected with an electron and muon with opposite charges that both have transverse impact parameter values between 0.02 and 2 cm. The search has been designed to be sensitive to a wide range of models with nonprompt e-μ final states. Limits are set on the “displaced supersymmetry” model, with pair production of top squarks decaying into an e-μ final state via R-parity-violating interactions. The results are the most restrictive to date on this model, with the most stringent limit being obtained for a top squark lifetime corresponding to cτ=2 cm, excluding masses below 790 GeV at 95% confidence level.

  1. Syntectonic remagnetization in the southern Methow block: Resolving large displacements in the southern Canadian Cordillera

    USGS Publications Warehouse

    Enkin, R.J.; Mahoney, J.B.; Baker, J.; Kiessling, M.; Haugerud, R.A.

    2002-01-01

    The Upper Cretaceous Ventura Member of the Goat Wall unit in the southern Methow block of southern British Columbia and northern Washington State holds a syntectonic magnetization. Eight new sites from Manning Park in British Columbia give a mean direction of D = 27.5??, I = 60.1??, k = 304.7, ??95 = 3.2?? after optimal partial tilt correction. Of five groups of bedded sites from farther south in the basin reported by Bazard et al. [1990], four have a syntectonic remanence with a direction similar to what we observe. The exception is one group which has optimal concentration of remanence directions on >100% untilting and an abherent direction which must be rejected. Combining the accepted sites, the optimal differential syntilting direction is D = 11.8??, I = 61.5??, k = 39.3, ??95 = 3.4?? (N = 47), giving a mean pole of 79.8??N, 359.2??E, K = 19.5, and A95 = 4.8??. The age of the remagnetization is constrained to be between 88 and 80 Ma. Compared to cratonic North America, this result indicates that the southern Methow block was displaced from the south by 1800 ?? 500 km, meaning it lay south of the Sierra Nevada subduction zone but well north of other paleomagnetically constrained Cretaceous rock units from the Insular superterrane, including correlative strata of the Mount Tatlow area in the northern Methow block. Among several possibilities to reconcile this discrepancy, the most plausible has the whole Methow block translated coherently but with the southern Methow block strata remagnetized during transit.

  2. A three-degree-of-freedom thin-film PZT-actuated microactuator with large out-of-plane displacement

    PubMed Central

    Choi, Jongsoo; Qiu, Zhen; Rhee, Choong-Ho; Wang, Thomas; Oldham, Kenn

    2014-01-01

    A novel three degree-of-freedom microactuator based on thin-film lead-zirconate-titanate (PZT) is described with its detailed structural model. Its central rectangular-shaped mirror platform, also referred to as the stage, is actuated by four symmetric PZT bending legs such that each leg provides vertical translation for one corner of the stage. It has been developed to support real-time in vivo vertical cross-sectional imaging with a dual axes confocal endomicroscope for early cancer detection, having large displacements in three axes (z, θx, θy) and a relatively high bandwidth in the z-axis direction. Prototype microactuators closely meet the performance requirements for this application; in the out-of-plane (z-axis) direction, it has shown more than 177 μm of displacement and about 84 Hz of structural natural frequency, when two diagonal legs are actuated at 14V. With all four legs, another prototype of the same design with lighter stage mass has achieved more than 430 μm of out-of-plane displacement at 15V and about 200 Hz of bandwidth. The former design has shown approximately 6.4° and 2.9° of stage tilting about the x-axis and y-axis, respectively, at 14V. This paper also presents a modeling technique that uses experimental data to account for the effects of fabrication uncertainties in residual stress and structural dimensions. The presented model predicts the static motion of the stage within an average absolute error of 14.6 μm, which approaches the desired imaging resolution, 5 μm, and also reasonably anticipates the structural dynamic behavior of the stage. The refined model will support development of a future trajectory tracking controller for the system. PMID:25506131

  3. A three-degree-of-freedom thin-film PZT-actuated microactuator with large out-of-plane displacement

    NASA Astrophysics Data System (ADS)

    Choi, Jongsoo; Qiu, Zhen; Rhee, Choong-Ho; Wang, Thomas; Oldham, Kenn

    2014-07-01

    A novel three degree-of-freedom microactuator based on thin-film lead-zirconate-titanate (PZT) is described with its detailed structural model. Its central rectangular-shaped mirror platform, also referred to as the stage, is actuated by four symmetric PZT bending legs such that each leg provides vertical translation for one corner of the stage. It has been developed to support real-time in vivo vertical cross-sectional imaging with a dual axes confocal endomicroscope for early cancer detection, having large displacements in three axes (z, θx, θy) and a relatively high bandwidth in the z-axis direction. Prototype microactuators closely meet the performance requirements for this application; in the out-of-plane (z-axis) direction, it has shown more than 177 μm of displacement and about 84 Hz of structural natural frequency, when two diagonal legs are actuated at 14V. With all four legs, another prototype of the same design with lighter stage mass has achieved more than 430 μm of out-of-plane displacement at 15V and about 200 Hz of bandwidth. The former design has shown approximately 6.4° and 2.9° of stage tilting about the x-axis and y-axis, respectively, at 14V. This paper also presents a modeling technique that uses experimental data to account for the effects of fabrication uncertainties in residual stress and structural dimensions. The presented model predicts the static motion of the stage within an average absolute error of 14.6 μm, which approaches the desired imaging resolution, 5 μm, and also reasonably anticipates the structural dynamic behavior of the stage. The refined model will support development of a future trajectory tracking controller for the system.

  4. Large dynamic range Atomic Force Microscope for overlay improvements

    NASA Astrophysics Data System (ADS)

    Kuiper, Stefan; Fritz, Erik; Crowcombe, Will; Liebig, Thomas; Kramer, Geerten; Witvoet, Gert; Duivenvoorde, Tom; Overtoom, Ton; Rijnbeek, Ramon; van Zwet, Erwin; van Dijsseldonk, Anton; den Boef, Arie; Beems, Marcel; Levasier, Leon

    2016-03-01

    Nowadays most overlay metrology tools assess the overlay performance based on marker features which are deposited next to the functional device features within each layer of the semiconductor device. However, correct overlay of the relatively coarse marker features does not directly guarantee correct overlay of the much smaller device features. This paper presents the development of a tool that allows to measure the relative distance between the marker and device features within each layer of the semiconductor device, which can be used to improve the overlay at device feature level. In order to be effective, the marker to device feature distance should be measured with sub-nanometer measurement uncertainty over several millimeters range. Furthermore, the tool should be capable of profiling the marker features to allows prediction of the location interpretation of the optical diffraction based alignment sensors, which are sensitive for potential asymmetry of the marker features. To enable this, a highly stable Atomic Force Microscope system is being developed. The probe is positioned relative to the wafer with a 6DOF controlled hexapod stage, which has a relatively large positioning range of 8x8mm. The position and orientation of this stage is measured relative to the wafer using 6 interferometers via a highly stable metrology frame. A tilted probe concept is utilized to allow profiling of the high aspect ratio marker and device features. Current activities are aimed at demonstrating the measurement capabilities of the developed AFM system.

  5. The variations in space of the displacement response spectrum at large periods using k-net data

    NASA Astrophysics Data System (ADS)

    Herrero, A.

    2012-12-01

    I use the large magnitude inland earthquakes of Japan, recorded by the accelerometric K-net network to study the spatial variations of the displacement response spectra (SD) at large frequencies. The scope is to observe directly the low frequency patterns of the seismic source radiation such as the focal mechanism and the directivity, since the asymptotic value of the displacement response spectra is the peak ground displacement (PGD). The advantage of using the SD as a proxy to the PGD, compared to a direct estimation on a double integration of the acceleration, is its stability and its simplicity. No signal processing is required to compute large period ordinates of the SD except a simple mean removal and a padding. I choose as reference a period of 10 sec. Its decay with the distance shows that it is linked mainly to the surface waves. Thus I present this type of data corrected by the square root of the distance (SD10R). I study different earthquakes with focal mechanisms either strike or dip slip. The first example is the 2000 Tottori Earthquake which is didactic since its mechanism is a strike slip and it is a well study case. When all the SD10R values are plotted on a map, they show directly the nodes of the focal mechanism as it was shown before by Takemura and al. (2009) with the S waves. The map of the SD10R deduced from the tangential components exhibits a radiation pattern characteristic of the Love's wave meanwhile a 45° rotation is observed on the SD10R map computed with the vertical component, corresponding to a Rayleigh's wave pattern. The plot of the SD10 parameter versus the azimuth shows also clearly the lobes of the focal mechanism. When the natural period of the oscillator is reduced toward 1 sec., the focal mechanism imprint vanishes around 3 sec., which is a much lower frequency that the one found by Takemura and al. (2009). However, the data are not the same as well as the measured parameter.ocal mechanism nodes observed with the SD10R

  6. How large are nonadiabatic effects in atomic and diatomic systems?

    SciTech Connect

    Yang, Yubo; Kylänpää, Ilkka; Tubman, Norm M.; Krogel, Jaron T.; Hammes-Schiffer, Sharon; Ceperley, David M.

    2015-09-29

    With recent developments in simulating nonadiabatic systems to high accuracy, it has become possible to determine how much energy is attributed to nuclear quantum effects beyond zero-point energy. Here, we calculate the non-relativistic ground-state energies of atomic and molecular systems without the Born-Oppenheimer approximation. For this purpose, we utilize the fixed-node diffusion Monte Carlo method, in which the nodes depend on both the electronic and ionic positions. Our report shows the ground-state energies for all systems studied, ionization energies for the first-row atoms and atomization energies for the first-row hydrides. We find the ionization energies of the atoms to be nearly independent of the Born-Oppenheimer approximation, within the accuracy of our results. The atomization energies of molecular systems, however, show small effects of the nonadiabatic coupling between electrons and nuclei.

  7. How large are nonadiabatic effects in atomic and diatomic systems?

    DOE PAGESBeta

    Yang, Yubo; Kylänpää, Ilkka; Tubman, Norm M.; Krogel, Jaron T.; Hammes-Schiffer, Sharon; Ceperley, David M.

    2015-09-29

    With recent developments in simulating nonadiabatic systems to high accuracy, it has become possible to determine how much energy is attributed to nuclear quantum effects beyond zero-point energy. Here, we calculate the non-relativistic ground-state energies of atomic and molecular systems without the Born-Oppenheimer approximation. For this purpose, we utilize the fixed-node diffusion Monte Carlo method, in which the nodes depend on both the electronic and ionic positions. Our report shows the ground-state energies for all systems studied, ionization energies for the first-row atoms and atomization energies for the first-row hydrides. We find the ionization energies of the atoms to bemore » nearly independent of the Born-Oppenheimer approximation, within the accuracy of our results. The atomization energies of molecular systems, however, show small effects of the nonadiabatic coupling between electrons and nuclei.« less

  8. How large are nonadiabatic effects in atomic and diatomic systems?

    SciTech Connect

    Yang, Yubo E-mail: normantubman2015@u.northwestern.edu; Tubman, Norm M. E-mail: normantubman2015@u.northwestern.edu; Ceperley, David M.; Kylänpää, Ilkka; Krogel, Jaron T.; Hammes-Schiffer, Sharon

    2015-09-28

    With recent developments in simulating nonadiabatic systems to high accuracy, it has become possible to determine how much energy is attributed to nuclear quantum effects beyond zero-point energy. In this work, we calculate the non-relativistic ground-state energies of atomic and molecular systems without the Born-Oppenheimer approximation. For this purpose, we utilize the fixed-node diffusion Monte Carlo method, in which the nodes depend on both the electronic and ionic positions. We report ground-state energies for all systems studied, ionization energies for the first-row atoms and atomization energies for the first-row hydrides. We find the ionization energies of the atoms to be nearly independent of the Born-Oppenheimer approximation, within the accuracy of our results. The atomization energies of molecular systems, however, show small effects of the nonadiabatic coupling between electrons and nuclei.

  9. How large are nonadiabatic effects in atomic and diatomic systems?

    NASA Astrophysics Data System (ADS)

    Yang, Yubo; Kylänpää, Ilkka; Tubman, Norm M.; Krogel, Jaron T.; Hammes-Schiffer, Sharon; Ceperley, David M.

    2015-09-01

    With recent developments in simulating nonadiabatic systems to high accuracy, it has become possible to determine how much energy is attributed to nuclear quantum effects beyond zero-point energy. In this work, we calculate the non-relativistic ground-state energies of atomic and molecular systems without the Born-Oppenheimer approximation. For this purpose, we utilize the fixed-node diffusion Monte Carlo method, in which the nodes depend on both the electronic and ionic positions. We report ground-state energies for all systems studied, ionization energies for the first-row atoms and atomization energies for the first-row hydrides. We find the ionization energies of the atoms to be nearly independent of the Born-Oppenheimer approximation, within the accuracy of our results. The atomization energies of molecular systems, however, show small effects of the nonadiabatic coupling between electrons and nuclei.

  10. How large are nonadiabatic effects in atomic and diatomic systems?

    PubMed

    Yang, Yubo; Kylänpää, Ilkka; Tubman, Norm M; Krogel, Jaron T; Hammes-Schiffer, Sharon; Ceperley, David M

    2015-09-28

    With recent developments in simulating nonadiabatic systems to high accuracy, it has become possible to determine how much energy is attributed to nuclear quantum effects beyond zero-point energy. In this work, we calculate the non-relativistic ground-state energies of atomic and molecular systems without the Born-Oppenheimer approximation. For this purpose, we utilize the fixed-node diffusion Monte Carlo method, in which the nodes depend on both the electronic and ionic positions. We report ground-state energies for all systems studied, ionization energies for the first-row atoms and atomization energies for the first-row hydrides. We find the ionization energies of the atoms to be nearly independent of the Born-Oppenheimer approximation, within the accuracy of our results. The atomization energies of molecular systems, however, show small effects of the nonadiabatic coupling between electrons and nuclei. PMID:26429012

  11. Large-Area Atom Interferometry with Frequency-Swept Raman Adiabatic Passage.

    PubMed

    Kotru, Krish; Butts, David L; Kinast, Joseph M; Stoner, Richard E

    2015-09-01

    We demonstrate light-pulse atom interferometry with large-momentum-transfer atom optics based on stimulated Raman transitions and frequency-swept adiabatic rapid passage. Our atom optics have produced momentum splittings of up to 30 photon recoil momenta in an acceleration-sensitive interferometer for laser cooled atoms. We experimentally verify the enhancement of phase shift per unit acceleration and characterize interferometer contrast loss. By forgoing evaporative cooling and velocity selection, this method lowers the atom shot-noise-limited measurement uncertainty and enables large-area atom interferometry at higher data rates. PMID:26382675

  12. Finite-element formulation for the analysis of interfaces, nonlinear and large displacement problems in geotechnical engineering

    NASA Astrophysics Data System (ADS)

    Zeevaert, A. E.

    1980-03-01

    A mathematical formulation to model the behavior under load of a reinforced soil system, where a fabric is placed over a soft soil and covered with stone for use as a temporary haul road is discussed. This approach is used to improve the behavior of temporary roadways, particularly where very soft soils are encountered. The stress distribution and the load-deformation characteristics of the soil-fabric system for varying geometries and material properties are defined. Included in the mathematical formulation are such features as: nonlinear behavior of the soil and fabric materials, friction parameters of the interface, tension characteristics of the fabric materials, large displacements in finite deformation, "no tension" conditions of the cohesionless materials, and yielding of plastic materials. The mathematical model is a more complete approximation of the actual fabric-soil system than is presently available.

  13. Charge-screening role of c-axis atomic displacements in YBa2Cu3O6+x and related superconductors

    DOE PAGESBeta

    E. S. Bozin; Huq, A.; Shen, Bing; Claus, H.; Kwok, W. K.; Tranquada, J. M.

    2016-02-29

    Here, the importance of charge reservoir layers for supplying holes to the CuO2 planes of cuprate superconductors has long been recognized. Less attention has been paid to the screening of the charge transfer by the intervening ionic layers. We address this issue in the case of YBa2Cu3O6+x, where CuO chains supply the holes for the planes. We present a simple dielectric-screening model that gives a linear correlation between the relative displacements of ions along the c axis, determined by neutron powder diffraction, and the hole density of the planes. Applying this model to the temperature-dependent shifts of ions along themore » c axis, we infer a charge transfer of 5–10% of the hole density from the planes to the chains on warming from the superconducting transition to room temperature. Given the significant coupling of c-axis displacements to the average charge density, we point out the relevance of local displacements for screening charge modulations and note recent evidence for dynamic screening of in-plane quasiparticles. This line of argument leads us to a simple model for atomic displacements and charge modulation that is consistent with images from scanning-tunneling microscopy for underdoped Bi2Sr2CaCu2O8+δ.« less

  14. Atomic Displacements at a Σ3(111) Grain Boundary in BaTiO_3: A First-principles Determination

    NASA Astrophysics Data System (ADS)

    Zhao, Y. J.; Geng, W. T.; Kim, Miyoung; Freeman, A. J.; Delley, B.

    2000-03-01

    BaTiO3 based ceramics are extensively used in the production of many electroceramic components such as capacitors and positive temperature coefficient thermistors. The electrical properties are known to be grain boundary(GB) phenomena and related to their atomic structure near the grain boundary(K. Hayashi, et al., J. Am. Ceram. Soc., 79), 1669(1996). Jia and Thust(C.L. Jia and A. Thust, Phys. Rev. Lett. 82), 5052 (1999) observed an expansion of the Ti-Ti spacing across the Σ3(111) GB in cubic BaTiO3 by use of high-resolution transmission electron microscopy along with an exit plane wave analysis. We employed the first-principles band structure DMol3 total energy/atomic force method( B. Delley, J. Chem. Phys. 92), 508(1990) within LDA to investigate the atomic and electronic structures at a Σ3(111) GB in cubic BaTiO_3. Full relaxation of the atomic structure was determined according to the calculated atomic forces. Our first-principles calculations indicate an expansion of the nearest Ti-Ti spacing across the GB plane and a contraction of the nearest BaO-BaO spacing, in good agreement with experiment. The origin of the atomic displacements were then explained with an electronic structure analysis.

  15. How Large are Nonadiabatic Effects in Atomic and Diatomic Systems?

    NASA Astrophysics Data System (ADS)

    Yang, Yubo; Kylanpaa, Ilkka; Tubman, Norm; Krogel, Jaron; Hammes-Schiffer, Sharon; Ceperley, David

    We have developed a fixed-node quantum Monte Carlo method to simulate atoms and molecules without the Born-Oppenheimer approximation with sub milli-Hartree accuracy. For this purpose, we construct trial wave functions with nodes that depend on both the electronic and ionic positions. We report ground-state energies and the ionization energies for the first-row atoms and atomization energies for the first-row hydrides. The latter show effects of the nonadiabatic coupling between electrons and nuclei. We discuss how the method scales to larger systems. DOE DE-FG02-12ER46875, DOE DE-NA0001789, NSF CHE-13-61293, NSF OCI-1053575, DOE DE-AC05- 00OR22725.

  16. Observation of a Large Atomic Parity Violation Effect in Ytterbium

    SciTech Connect

    Tsigutkin, K.; Dounas-Frazer, D.; Family, A.; Stalnaker, J. E.; Yashchuk, V. V.; Budker, D.

    2009-08-14

    Atomic parity violation has been observed in the 6s{sup 2} {sup 1}S{sub 0}->5d6s {sup 3}D{sub 1} 408-nm forbidden transition of ytterbium. The parity-violating amplitude is found to be 2 orders of magnitude larger than in cesium, where the most precise experiments to date have been performed. This is in accordance with theoretical predictions and constitutes the largest atomic parity-violating amplitude yet observed. This also opens the way to future measurements of neutron distributions and anapole moments by comparing parity-violating amplitudes for various isotopes and hyperfine components of the transition.

  17. Neutron scattering studies of short-range order, atomic displacements, and effective pair interactions in a null-matrix Ni0.5262Pt0.48 crystal

    NASA Astrophysics Data System (ADS)

    Rodriguez, J. A.; Moss, S. C.; Robertson, J. L.; Copley, J. R. D.; Neumann, D. A.; Major, J.

    2006-09-01

    The best known exception to the Heine-Sampson and Bieber-Gauthier arguments for ordering effects in transition metal alloys (similar to the Hume-Rothery rules) is a NiPt alloy, whose phase diagram is similar to that of the CuAu system. Using neutron scattering we have investigated the local atomic order in a null-matrix Ni0.5262Pt0.48 single crystal. In a null-matrix alloy, the isotopic composition is adjusted so that the average neutron scattering length vanishes ( Ni62 has a negative scattering length nearly equal in magnitude to that of Pt). Consequently, all contributions to the total scattering depending on the average lattice are suppressed. The only remaining components of the elastic scattering are the short-range order (SRO) and size effect terms. These data permit the extraction of the SRO parameters (concentration-concentration correlations) as well as the displacement parameters (concentration-displacement correlations). Using the Krivoglaz-Clapp-Moss theory, we obtain the effective pair interactions (EPIs) between near neighbors in the alloy. The results can be used by theorists to model the alloy in the context of the electronic theory of alloy phase stability, including a preliminary evaluation of the local species-dependent displacements. Our maps of V(q) , the Fourier transform of the EPIs, show very similar shapes in the experimental and reconstructed data. This is of importance when comparing to electronic structure calculations.

  18. Low spring index, large displacement Shape Memory Alloy (SMA) coil actuators for use in macro- and micro-systems

    NASA Astrophysics Data System (ADS)

    Holschuh, Brad; Newman, Dava

    2014-03-01

    Shape memory alloys (SMA) offer unique shape changing characteristics that can be exploited to produce low­ mass, low-bulk, large-stroke actuators. We are investigating the use of low spring index (defined as the ratio of coil diameter to wire diameter) SMA coils for use as actuators in morphing aerospace systems. Specifically, we describe the development and characterization of minimum achievable spring index coiled actuators made from 0.3048 mm (0.012") diameter shape memory alloy (SMA) wire for integration in textile architectures for future compression space suit applications. Production and shape setting of the coiled actuators, as well as experimental test methods, are described. Force, length and voltage relationships for multiple coil actuators are reported and discussed. The actuators exhibit a highly linear (R2 < 0.99) relationship between isometric blocking force and coil displacement, which is consistent with current SMA coil models; and SMA coil actuators demonstrate the ability to produce significant linear forces (i.e., greater than 8 N per coil) at strains up to 3x their initial (i.e., fully coiled) length. Discussions of both the potential use of these actuators in future compression space suit designs, and the broader viability of these actuators in both macro- and micro-systems, are presented.

  19. Simultaneous piston position and tilt angle sensing for large vertical displacement micromirrors by frequency detection inductive sensing

    NASA Astrophysics Data System (ADS)

    Tseng, V. F.-G.; Xie, H.

    2015-11-01

    This paper presents a frequency detection based inductive eddy current sensing mechanism to simultaneously sense the piston position and tilt angle of the mirror plate of large vertical displacement micromirrors that exhibit piston scan ranges above 100 μm. This is accomplished by sensing the inductance change, and thus resonant frequency shift, of two microfabricated sensing coils packaged underneath the mirror plate. For demonstration purpose, the coils were paired with discrete circuit components to oscillate at 11.9 MHz and 12.5 MHz, respectively. The piston position and tilt angle of the mirror plate could be simultaneously monitored over a 500 μm piston scan range, achieving a maximum piston sensitivity of 4.15 kHz/μm with a piston sensing resolution of 96 nm and a maximum tilt angle sensitivity of 60.5 kHz/° with a tilt angle sensing resolution of 0.0013°. Analytical modeling of the coil inductance change via image theory was also conducted, showing that the sensor sensitivity and resolution could be improved by increasing the coil oscillation frequency and decreasing the coil size.

  20. A vision-based system for measuring the displacements of large structures: Simultaneous adaptive calibration and full motion estimation

    NASA Astrophysics Data System (ADS)

    Santos, C. Almeida; Costa, C. Oliveira; Batista, J.

    2016-05-01

    The paper describes a kinematic model-based solution to estimate simultaneously the calibration parameters of the vision system and the full-motion (6-DOF) of large civil engineering structures, namely of long deck suspension bridges, from a sequence of stereo images captured by digital cameras. Using an arbitrary number of images and assuming a smooth structure motion, an Iterated Extended Kalman Filter is used to recursively estimate the projection matrices of the cameras and the structure full-motion (displacement and rotation) over time, helping to meet the structure health monitoring fulfilment. Results related to the performance evaluation, obtained by numerical simulation and with real experiments, are reported. The real experiments were carried out in indoor and outdoor environment using a reduced structure model to impose controlled motions. In both cases, the results obtained with a minimum setup comprising only two cameras and four non-coplanar tracking points, showed a high accuracy results for on-line camera calibration and structure full motion estimation.

  1. Optimal size, shape, and control design in dynamics of planar frame structures under large displacements and rotations

    NASA Astrophysics Data System (ADS)

    Gams, M.; Saje, M.; Planinc, I.; Kegl, M.

    2010-01-01

    Size, shape, and drive optimization procedures are combined with an energy-conserving time-integration scheme for the dynamic analysis of planar geometrically non-linear frame structures undergoing large overall motions. The solution method is based on the finite-element formulation, employing the classical displacement-based planar beam finite elements described in an inertial frame. Finite axial, bending, and shear strains are taken into account. If the system is conservative, the energy and momenta conservation in the discrete system during motion is guaranteed. Size, shape, and drive design variables are introduced into the model. Shape parameterization is achieved by the design element technique, using Bezier patches. The sensitivity analysis is performed by the discrete approach and the analytical direct differentiation method. A gradient-based optimization method, using an automatically adjustable convex approximation technique, is employed. The efficiency and the applicability of the approach are demonstrated via numerical examples. The shape and the driving function of a load-moving robot arm are optimized to reduce oscillations in its final position. The shape of a steel frame is optimized to reduce oscillations after an idealized ground motion jerk.

  2. Neutron scattering studies of short-range order and atomic displacements in a null-matrix nickel-62 platinum crystal

    NASA Astrophysics Data System (ADS)

    Rodriguez, Jose Abelardo

    The best known exception to the Heine-Samson and Bieber-Gautier arguments for ordering effects in transition metal alloys (similar to the Hume-Rothery rules) is a NiPt alloy, where the phase diagram is similar to the CuAu system. Using the Disk Chopper Spectrometer (DCS) at NIST, we have investigated a Null-Matrix Crystal 62 Ni0.52Pt0.48, (62 Ni has a negative scattering length, nearly equal in magnitude to Pt). Its composition has therefore been chosen whereby all effects depending on the average lattice scattering vanish. The only remaining contributions to the diffuse scattering are the Short Range Order (SRO) and Size Effect (SE) terms, to be discussed within. Such data permit the extraction of the SRO parameters (concentration-concentration correlations) as well as the displacement parameters (concentration-displacement correlations). Using the Krivoglaz-Clapp-Moss theory, we obtained the Effective Pair Interactions (EPI) between the several neighbors in the alloy. The results can be used to model the alloy in the context of electronic theory of alloy phase stability, including an evaluation of the potentially important aspect of charge transfer and ionicity.

  3. Superradiance in a Large and Dilute Cloud of Cold Atoms in the Linear-Optics Regime.

    PubMed

    Araújo, Michelle O; Krešić, Ivor; Kaiser, Robin; Guerin, William

    2016-08-12

    Superradiance has been extensively studied in the 1970s and 1980s in the regime of superfluorescence, where a large number of atoms are initially excited. Cooperative scattering in the linear-optics regime, or "single-photon superradiance," has been investigated much more recently, and superradiant decay has also been predicted, even for a spherical sample of large extent and low density, where the distance between atoms is much larger than the wavelength. Here, we demonstrate this effect experimentally by directly measuring the decay rate of the off-axis fluorescence of a large and dilute cloud of cold rubidium atoms after the sudden switch off of a low-intensity laser driving the atomic transition. We show that, at large detuning, the decay rate increases with the on-resonance optical depth. In contrast to forward scattering, the superradiant decay of off-axis fluorescence is suppressed near resonance due to attenuation and multiple-scattering effects. PMID:27563957

  4. Superradiance in a Large and Dilute Cloud of Cold Atoms in the Linear-Optics Regime

    NASA Astrophysics Data System (ADS)

    Araújo, Michelle O.; Krešić, Ivor; Kaiser, Robin; Guerin, William

    2016-08-01

    Superradiance has been extensively studied in the 1970s and 1980s in the regime of superfluorescence, where a large number of atoms are initially excited. Cooperative scattering in the linear-optics regime, or "single-photon superradiance," has been investigated much more recently, and superradiant decay has also been predicted, even for a spherical sample of large extent and low density, where the distance between atoms is much larger than the wavelength. Here, we demonstrate this effect experimentally by directly measuring the decay rate of the off-axis fluorescence of a large and dilute cloud of cold rubidium atoms after the sudden switch off of a low-intensity laser driving the atomic transition. We show that, at large detuning, the decay rate increases with the on-resonance optical depth. In contrast to forward scattering, the superradiant decay of off-axis fluorescence is suppressed near resonance due to attenuation and multiple-scattering effects.

  5. Ground state properties of cold bosonic atoms at large scattering lengths.

    PubMed

    Song, Jun Liang; Zhou, Fei

    2009-07-10

    In this Letter, we study bosonic atoms at large scattering lengths using a variational method where the condensate amplitude is a variational parameter. We further examine momentum distribution functions, chemical potentials, the speed of sound, and spatial density profiles of cold bosonic atoms in a trap in this limit. The latter two properties turn out to bear similarities to those of Fermi gases. The estimates obtained here are applicable near Feshbach resonances, particularly when the fraction of atoms forming three-body structures is small and can be tested in future cold atom experiments. PMID:19659218

  6. Design of a MEMS-based motion stage based on a lever mechanism for generating large displacements and forces

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Sik; Shi, Hongliang; Dagalakis, Nicholas G.; Gupta, Satyandra K.

    2016-09-01

    Conventional miniaturized motion stages have a volume of 50–60 cm3 and a range of motion around 100 μm. Micro-electro-mechanical systems (MEMS)-based motion stages have been good alternatives in some applications for small footprint, micron-level accuracy, and a lower cost. However, existing MEMS-based motion stages are able to provide a force of μN level, small displacements (less than tens of microns), and need additional features for practical applications like a probe or a stage. In this paper, a single degree of freedom motion stage is designed and analyzed for a larger displacement, a larger output force, a smaller out-of-plane deformation, and a bigger moving stage for further applications. For these purposes, the presented motion stage is designed with a thermal actuator, folded springs, and a lever, and it is experimentally characterized. Furthermore, three different types of flexure joints are investigated to characterize their capabilities and suitability to serve as the revolute joint of the lever: a beam, a cartwheel, and a butterfly flexure. The presented motion stage has a moving stage of 15 mm  ×  15 mm and shows a maximum displacement over 80 μm, and out-of-plane deformation under a weight of 120 μN less than 2 μm. The force generated by the actuator is estimated to be 68.6 mN.

  7. Large two-atom two-photon vacuum Rabi oscillations in a high-quality cavity

    SciTech Connect

    Pathak, P.K.; Agarwal, G.S.

    2004-10-01

    We predict a large cooperative effect involving two-atom two-photon vacuum Rabi oscillations in a high-quality cavity. The two-photon emission occurs as a result of simultaneous deexcitation of both atoms with two-photon resonance condition {omega}{sub 1}+{omega}{sub 2}{approx_equal}{omega}{sub a}+{omega}{sub b}, where {omega}{sub 1},{omega}{sub 2} are the atomic transition frequencies and {omega}{sub a},{omega}{sub b} are the frequencies of the emitted photons. The actual resonance condition depends on the vacuum Rabi couplings. The effect can be realized either with identical atoms in a bimodal cavity or with nonidentical atoms in a single-mode cavity.

  8. Selective quantification of trace palladium in road dusts and roadside soils by displacement solid-phase extraction online coupled with electrothermal atomic absorption spectrometry.

    PubMed

    Fang, Jing; Jiang, Yan; Yan, Xiu-Ping; Ni, Zhe-Ming

    2005-01-01

    There is a growing concern about the effect of palladium on human health because of the toxicity and increasing occurrence of palladium as a result of its extensive use in automotive catalytic converters. Development of reliable analytical methodologies for the determination of palladium in environmental materials is of great importance for critical evaluation of the possible risks for human health. In this work, a displacement solid-phase extraction technique was developed and online coupled to electrothermal atomic absorption spectrometry (ETAAS) for selective and sensitive determination of trace palladium in environmental samples without need of any special selective complexing agents, selective sorbents, and masking agents. The developed methodology involved the online formation of copper pyrrolidine dithiocarbamate (Cu-PDC), and the resultant Cu-PDC was extracted onto a microcolumn packed with the sorbent from a cigarette filter. Trace Pd(II) was selectively preconcentrated through loading the sample solution onto the microcolumn by online displacement reaction between Pd(II) and the extracted Cu-PDC on the microcolumn. The retained analyte was subsequently eluted with 40 microL of ethanol for online ETAAS determination. Interferences from coexisting heavy metal ions with lower stability of their PDC complexes relative to Cu-PDC were minimized. The tolerable concentrations of Cd-(II), Fe(III), Co(II), Mn(II), Cr(III), and Zn(II) were up to 2, 6, 40, 2, 1.5, and at least 100 mg L(-1), respectively. Compared with conventional solid-phase extraction methodology, the developed displacement solid-phase extraction protocol gave 2-4 orders of magnitude improvement in the maximum tolerable concentrations of coexisting heavy metal ions. With the consumption of only 2.8 mL of sample solution, an enhancement factor of 52 and a detection limit (3sigma) of 18 ng L(-1) were achieved at a sample throughput of 30 samples h(-1). The precision (RSD, n = 13) was 2.5% at the 1

  9. Three-Body Recombination of {sup 6}Li Atoms with Large Negative Scattering Lengths

    SciTech Connect

    Braaten, Eric; Kang, Daekyoung; Platter, Lucas; Hammer, H.-W.

    2009-08-14

    The three-body recombination rate at threshold for distinguishable atoms with large negative pair scattering lengths is calculated in the zero-range approximation. The only parameters in this limit are the 3 scattering lengths and the Efimov parameter, which can be complex-valued. We provide semianalytic expressions for the cases of 2 or 3 equal scattering lengths, and we obtain numerical results for the general case of 3 different scattering lengths. Our general result is applied to the three lowest hyperfine states of {sup 6}Li atoms. Comparisons with recent experiments provide indications of loss features associated with Efimov trimers near the 3-atom threshold.

  10. Accommodation of Large Displacement along Thin Principal Slip Layer of a Fault: An Example of the Garam Thrust in the Paleozoic Taebaeksan Basin

    NASA Astrophysics Data System (ADS)

    Kim, S.; Ree, J.

    2009-12-01

    The principal slip layer (PSL) along which most of the shear displacement within a fault zone occurs is very narrow (less than 1-5 mm) and it is not so clear how this narrow layer accommodates a large (several m to several km) displacement. The NNW-striking and WSW-dipping Garam Thrust puts the Cambrian Wagok Formation on top of the Ordovician Mungok Formation in the Paleozoic Taebaeksan Basin of Korea. The Wagok Formation of the hanging wall is a massive dolostone consisting of euhedral dolomite grains (0.1-1 mm) and some fossil fragments. In contrast, the Mungok Formation of the footwall is a bedded limestone composed of calcite (20-150 μm) with some fossil fragments and dolomite. The estimated minimum displacement of the thrust is about 120 m. The principal slip zone between the two formations is only 3-10 mm thick and filled by vein calcites (100-500 μm in size) with foam texture. The hanging wall dolostone is highly fractured or “pulverized” while the footwall limestone is almost intact except a micro shear zone near the principal slip layer. In and adjacent to the principal slip layer, there are no fault rocks such as gouge or cataclasite. Prismatic euhedral quartz grains (100-200 μm long) occurs within and around the principal slip layer suggesting infiltration of fluid rich in silica as well as carbonate along the principal slip layer. In view of the absence of fault rocks within and adjacent to the principal slip layer, the possible accommodation processes of the large displacement along the thin layer may include fault lubrication by nano-crystalline decomposition products of carbonate minerals and fluid effect. To test these possibilities, textural analyses on the principal slip zone and micro shear zone using scanning electron microscopy are under way and we will discuss these results.

  11. Ultraviolet light-induced atom desorption for large rubidium and potassium magneto-optical traps

    SciTech Connect

    Klempt, C.; Zoest, T. van; Henninger, T.; Topic, O.; Rasel, E.; Ertmer, W.; Arlt, J.

    2006-01-15

    We show that light-induced atom desorption (LIAD) can be used as a flexible atomic source for large {sup 87}Rb and {sup 40}K magneto-optical traps. The use of LIAD at short wavelengths allows for fast switching of the desired vapor pressure and permits experiments with long trapping and coherence times. The wavelength dependence of the LIAD effect for both species was explored in a range from 630 to 253 nm in an uncoated quartz cell and a stainless steel chamber. Only a few mW/cm{sup 2} of near-UV light produce partial pressures that are high enough to saturate a magneto-optical trap at 3.5x10{sup 9} {sup 87}Rb atoms or 7x10{sup 7} {sup 40}K atoms. Loading rates as high as 1.2x10{sup 9} {sup 87}Rb atoms/s and 8x10{sup 7} {sup 40}K atoms/s were achieved without the use of a secondary atom source. After the desorption light is turned off, the pressure quickly decays back to equilibrium with a time constant as short as 200 {mu}s, allowing for long trapping lifetimes after the MOT loading phase.

  12. 102({h_bar}/2{pi})k Large Area Atom Interferometers

    SciTech Connect

    Chiow, Sheng-wey; Kovachy, Tim; Chien, Hui-Chun; Kasevich, Mark A.

    2011-09-23

    We demonstrate atom interferometers utilizing a novel beam splitter based on sequential multiphoton Bragg diffractions. With this sequential Bragg large momentum transfer (SB-LMT) beam splitter, we achieve high contrast atom interferometers with momentum splittings of up to 102 photon recoil momenta (102({h_bar}/2{pi})k). To our knowledge, this is the highest momentum splitting achieved in any atom interferometer, advancing the state-of-the-art by an order of magnitude. We also demonstrate strong noise correlation between two simultaneous SB-LMT interferometers, which alleviates the need for ultralow noise lasers and ultrastable inertial environments in some future applications. Our method is intrinsically scalable and can be used to dramatically increase the sensitivity of atom interferometers in a wide range of applications, including inertial sensing, measuring the fine structure constant, and detecting gravitational waves.

  13. Optimization of evaporative cooling towards a large number of Bose-Einstein-condensed atoms

    SciTech Connect

    Yamashita, Makoto; Mukai, Tetsuya; Mukai, Takaaki; Koashi, Masato; Mitsunaga, Masaharu; Imoto, Nobuyuki

    2003-02-01

    We study the optimization of evaporative cooling in trapped bosonic atoms on the basis of quantum kinetic theory of a Bose gas. The optimized cooling trajectory for {sup 87}Rb atoms indicates that the acceleration of evaporative cooling around the transition point of Bose-Einstein condensation is very effective against loss of trapped atoms caused by three-body recombination. The number of condensed atoms is largely enhanced by the optimization, more than two orders of magnitude in our present calculation using relevant experimental parameters, as compared with the typical value given by the conventional evaporative cooling where the frequency of radio-frequency magnetic field is swept exponentially. In addition to this optimized cooling, it is also shown that highly efficient evaporative cooling can be achieved by an initial exponential and then a rapid linear sweep of frequency.

  14. Control of light trapping in a large atomic system by a static magnetic field

    NASA Astrophysics Data System (ADS)

    Skipetrov, S. E.; Sokolov, I. M.; Havey, M. D.

    2016-07-01

    We propose to control light trapping in a large ensemble of cold atoms by an external, static magnetic field. For an appropriate choice of frequency and polarization of the exciting pulse, the field is expected to speed up the fluorescence of a dilute atomic system. In a dense ensemble, the field does not affect the early-time superradiant signal but amplifies intensity oscillations at intermediate times and induces a very slow, nonexponential long-time decay. The slowing down of fluorescence is due to the excitation of spatially localized collective atomic states that appear only under a strong magnetic field and have exponentially long lifetimes. Our results therefore pave a way towards experimental observation of the disorder-induced localization of light in cold atomic systems.

  15. Effective-range corrections to three-body recombination for atoms with large scattering length

    SciTech Connect

    Hammer, H.-W.; Laehde, Timo A.; Platter, L.

    2007-03-15

    Few-body systems with large scattering length a have universal properties that do not depend on the details of their interactions at short distances. The rate constant for three-body recombination of bosonic atoms of mass m into a shallow dimer scales as ({Dirac_h}/2{pi})a{sup 4}/m times a log-periodic function of the scattering length. We calculate the leading and subleading corrections to the rate constant, which are due to the effective range of the atoms, and study the correlation between the rate constant and the atom-dimer scattering length. Our results are applied to {sup 4}He atoms as a test case.

  16. Molecular Dynamics Simulations from SNL's Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS)

    DOE Data Explorer

    Plimpton, Steve; Thompson, Aidan; Crozier, Paul

    LAMMPS (http://lammps.sandia.gov/index.html) stands for Large-scale Atomic/Molecular Massively Parallel Simulator and is a code that can be used to model atoms or, as the LAMMPS website says, as a parallel particle simulator at the atomic, meso, or continuum scale. This Sandia-based website provides a long list of animations from large simulations. These were created using different visualization packages to read LAMMPS output, and each one provides the name of the PI and a brief description of the work done or visualization package used. See also the static images produced from simulations at http://lammps.sandia.gov/pictures.html The foundation paper for LAMMPS is: S. Plimpton, Fast Parallel Algorithms for Short-Range Molecular Dynamics, J Comp Phys, 117, 1-19 (1995), but the website also lists other papers describing contributions to LAMMPS over the years.

  17. Hydrogen transport diagnostics by atomic and molecular emission line profiles simultaneously measured for large helical device

    SciTech Connect

    Fujii, K.; Shikama, T.; Hasuo, M.; Goto, M.; Morita, S.

    2013-01-15

    We observe the Balmer-{alpha}, -{beta}, and -{gamma} lines of hydrogen atoms and Q branches of the Fulcher-{alpha} band of hydrogen molecules simultaneously with their polarization resolved for large helical device. From the fit including the line splits and the polarization dependences by the Zeeman effect, the emission locations, intensities, and the temperatures of the atoms and molecules are determined. The emission locations of the hydrogen atoms are determined outside but close to the last closed flux surface (LCFS). The results are consistent with a previous work (Phys. Plasmas 12, 042501 (2005)). On the other hand, the emission locations of the molecules are determined to be in the divertor legs, which is farer from those of the atoms. The kinetic energy of the atoms is 1 {approx} 20 eV, while the rotational temperature of molecules is {approx}0.04 eV. Additionally, substantial wings, which originate from high velocity atoms and are not reproduced by the conventional spectral analysis, are observed in the Balmer line profiles. We develop a one-dimensional model to simulate the transport of the atoms and molecules. The model reproduces the differences of the emission locations of the atoms and molecules when their initial temperatures are assumed to be 3 eV and 0.04 eV, respectively. From the model, the wings of the Balmer-{alpha} line is attributed to the high velocity atoms exist deep inside the LCFS, which are generated by the charge exchange collisions with hot protons there.

  18. Contrasting styles of large-scale displacement of unconsolidated sand: examples from the early Jurassic Navajo Sandstone on the Colorado Plateau, USA

    NASA Astrophysics Data System (ADS)

    Bryant, Gerald

    2015-04-01

    Large-scale soft-sediment deformation features in the Navajo Sandstone have been a topic of interest for nearly 40 years, ever since they were first explored as a criterion for discriminating between marine and continental processes in the depositional environment. For much of this time, evidence for large-scale sediment displacements was commonly attributed to processes of mass wasting. That is, gravity-driven movements of surficial sand. These slope failures were attributed to the inherent susceptibility of dune sand responding to environmental triggers such as earthquakes, floods, impacts, and the differential loading associated with dune topography. During the last decade, a new wave of research is focusing on the event significance of deformation features in more detail, revealing a broad diversity of large-scale deformation morphologies. This research has led to a better appreciation of subsurface dynamics in the early Jurassic deformation events recorded in the Navajo Sandstone, including the important role of intrastratal sediment flow. This report documents two illustrative examples of large-scale sediment displacements represented in extensive outcrops of the Navajo Sandstone along the Utah/Arizona border. Architectural relationships in these outcrops provide definitive constraints that enable the recognition of a large-scale sediment outflow, at one location, and an equally large-scale subsurface flow at the other. At both sites, evidence for associated processes of liquefaction appear at depths of at least 40 m below the original depositional surface, which is nearly an order of magnitude greater than has commonly been reported from modern settings. The surficial, mass flow feature displays attributes that are consistent with much smaller-scale sediment eruptions (sand volcanoes) that are often documented from modern earthquake zones, including the development of hydraulic pressure from localized, subsurface liquefaction and the subsequent escape of

  19. Bichromatic Cooling used to Achieve a Large Number of Cold Atoms in a Compact Volume

    NASA Astrophysics Data System (ADS)

    Cubel Liebisch, Tara; Donley, Elizabeth; Blanshan, Eric; Kitching, John

    2010-03-01

    For cold atomic samples to be used in emerging technologies such as compact atomic clocks and sensors it is necessary to achieve small sample sizes with a large number of cold atoms. This is a challenge because in a magneto-optical trap (MOT) the number of cooled and trapped atoms scales as d^4, where d is the diameter of the laser beams (Gibble et.al.OL17, 526 (1992)). In a MOT the maximum radiation force is limited by spontaneous emission to hkγ/2. Bichromatic cooling first studied by Söding et.al. (PRL78,1420(1997)), takes advantage of stimulated emission and driven Rabi oscillations to cool atoms over a broad velocity range with forces >> hkγ/2. With the faster cooling rates, larger atom numbers can be obtained in very small cooling volumes. We report on preliminary results of cooling a thermal beam down to MOT capture velocities over distances of <1cm, our experimental set up, and theoretical results using our experimental parameters. We expect to be able to load a MOT with 1mm diameter beams with a factor of 100 more atoms than if loaded from a background vapor. With this atom sample we estimate we could achieve a clock stability of 1E-12 @ 1s with a Ramsey time of 4ms, a cycle time of 10ms, and a clock transition frequency of 6.8GHz. [0pt] We would like to acknowledge funding from NIST, DARPA, and NRC.

  20. Electronic transport in large systems through a QUAMBO-NEGF approach: Application to atomic carbon chains

    NASA Astrophysics Data System (ADS)

    Fang, X. W.; Zhang, G. P.; Yao, Y. X.; Wang, C. Z.; Ding, Z. J.; Ho, K. M.

    2011-10-01

    The conductance of single-atom carbon chain (SACC) between two zigzag graphene nanoribbons (GNR) is studied by an efficient scheme utilizing tight-binding (TB) parameters generated via quasi-atomic minimal basis set orbitals (QUAMBOs) and non-equilibrium Green's function (NEGF). Large systems (SACC contains more than 50 atoms) are investigated and the electronic transport properties are found to correlate with SACC's parity. The SACCs provide a stable off or on state in broad energy region (0.1-1 eV) around Fermi energy. The off state is not sensitive to the length of SACC while the corresponding energy region decreases with the increase of the width of GNR.

  1. Resonant atom-field interaction in large-size coupled-cavity arrays

    SciTech Connect

    Ciccarello, Francesco

    2011-04-15

    We consider an array of coupled cavities with staggered intercavity couplings, where each cavity mode interacts with an atom. In contrast to large-size arrays with uniform hopping rates where the atomic dynamics is known to be frozen in the strong-hopping regime, we show that resonant atom-field dynamics with significant energy exchange can occur in the case of staggered hopping rates even in the thermodynamic limit. This effect arises from the joint emergence of an energy gap in the free photonic dispersion relation and a discrete frequency at the gap's center. The latter corresponds to a bound normal mode stemming solely from the finiteness of the array length. Depending on which cavity is excited, either the atomic dynamics is frozen or a Jaynes-Cummings-like energy exchange is triggered between the bound photonic mode and its atomic analog. As these phenomena are effective with any number of cavities, they are prone to be experimentally observed even in small-size arrays.

  2. Novel Applications of Buffer-gas Cooling to Cold Atoms, Diatomic Molecules, and Large Molecules

    NASA Astrophysics Data System (ADS)

    Drayna, Garrett Korda

    Cold gases of atoms and molecules provide a system for the exploration of a diverse set of physical phenomena. For example, cold gasses of magnetically and electrically polar atoms and molecules are ideal systems for quantum simulation and quantum computation experiments, and cold gasses of large polar molecules allow for novel spectroscopic techniques. Buffer-gas cooling is a robust and widely applicable method for cooling atoms and molecules to temperatures of approximately 1 Kelvin. In this thesis, I present novel applications of buffer-gas cooling to obtaining gases of trapped, ultracold atoms and diatomic molecules, as well as the study of the cooling of large organic molecules. In the first experiment of this thesis, a buffer-gas beam source of atoms is used to directly load a magneto-optical trap. Due to the versatility of the buffer-gas beam source, we obtain trapped, sub-milliKelvin gases of four different lanthanide species using the same experimental apparatus. In the second experiment of this thesis, a buffer-gas beam is used as the initial stage of an experiment to directly laser cool and magneto-optically trap the diatomic molecule CaF. In the third experiment of this thesis, buffer-gas cooling is used to study the cooling of the conformational state of large organic molecules. We directly observe conformational relaxation of gas-phase 1,2-propanediol due to cold collisions with helium gas. Lastly, I present preliminary results on a variety of novel applications of buffer-gas cooling, such as mixture analysis, separation of chiral mixtures, the measurement of parity-violation in chiral molecules, and the cooling and spectroscopy of highly unstable reaction intermediates.

  3. Method for large-scale fabrication of atomic-scale structures on material surfaces using surface vacancies

    DOEpatents

    Lim, Chong Wee; Ohmori, Kenji; Petrov, Ivan Georgiev; Greene, Joseph E.

    2004-07-13

    A method for forming atomic-scale structures on a surface of a substrate on a large-scale includes creating a predetermined amount of surface vacancies on the surface of the substrate by removing an amount of atoms on the surface of the material corresponding to the predetermined amount of the surface vacancies. Once the surface vacancies have been created, atoms of a desired structure material are deposited on the surface of the substrate to enable the surface vacancies and the atoms of the structure material to interact. The interaction causes the atoms of the structure material to form the atomic-scale structures.

  4. The effect of large veins on spatial localization with GE BOLD at 3 T: Displacement, not blurring.

    PubMed

    Olman, Cheryl A; Inati, Souheil; Heeger, David J

    2007-02-01

    We used two different methods of region of interest (ROI) definition to investigate the spatial accuracy of functional magnetic resonance imaging (fMRI) at low and high spatial resolution. The "single-condition localizer" consisted of block alternation between a target stimulus and a mean gray background. The "differential localizer" consisted of block alternation between the target stimulus and another stimulus that filled the complement of the visual field. A separate series of scans, in which the target stimulus was presented briefly with long inter-stimulus intervals, was used to measure the hemodynamic impulse response function (HIRF). As expected, the differential localizer defined more restricted ROIs that better matched the predicted cortical representation of the target stimulus. However, at low resolution (3-mm isotropic) many voxels that responded positively to the target stimulus in the differential protocol responded negatively to the target stimulus in the single-condition localizer and in the HIRF measurements. The localization errors were attributed to voxels near large veins, which were identified based on low mean intensity and high variance. At high resolution (1.2-mm isotropic), the effects of large veins were present, but affected a smaller number of voxels. Thus, the use of differential localizers does not necessarily result in a more accurate indication of the underlying neural activity. Localization errors are reduced at higher spatial resolutions and can be eliminated by identification and removal of voxels dominated by large veins. PMID:17157534

  5. Simultaneous in-plane and out-of-plane displacement measurement based on a dual-camera imaging system and its application to inspection of large-scale space structures

    NASA Astrophysics Data System (ADS)

    Ri, Shien; Tsuda, Hiroshi; Yoshida, Takeshi; Umebayashi, Takashi; Sato, Akiyoshi; Sato, Eiichi

    2015-07-01

    Optical methods providing full-field deformation data have potentially enormous interest for mechanical engineers. In this study, an in-plane and out-of-plane displacement measurement method based on a dual-camera imaging system is proposed. The in-plane and out-of-plane displacements are determined simultaneously using two measured in-plane displacement data observed from two digital cameras at different view angles. The fundamental measurement principle and experimental results of accuracy confirmation are presented. In addition, we applied this method to the displacement measurement in a static loading and bending test of a solid rocket motor case (CFRP material; 2.2 m diameter and 2.3 m long) for an up-to-date Epsilon rocket developed by JAXA. The effectiveness and measurement accuracy is confirmed by comparing with conventional displacement sensor. This method could be useful to diagnose the reliability of large-scale space structures in the rocket development.

  6. Large area hexagonal boron nitride monolayer as efficient atomically thick insulating coating against friction and oxidation.

    PubMed

    Li, Xuemei; Yin, Jun; Zhou, Jianxin; Guo, Wanlin

    2014-03-14

    Coating is the most widely applied technology to improve surface properties of substrates, and nanotechnology has been playing an important role in enhancing the coating performance. However, the tunability of surface properties by a single atomic layer remains poorly understood. Here we demonstrate that a chemical vapor deposited hexagonal boron nitride (h-BN) monolayer of large area and high quality can serve as a perfect coating to significantly improve friction, oxidation and electric resistance of the substrates. The exceptional low friction and insulation of h-BN monolayer coating facilitate the characterization of the h-BN film vividly by atomic force microscopy, showing the h-BN monolayer consists of domains with size within a few micrometers. This excellent coating performance together with the exceptional high thermal and chemical stability make the h-BN monolayer a promising coating material. PMID:24532053

  7. Non-statistical fragmentation of large molecules in collisions with atoms

    NASA Astrophysics Data System (ADS)

    Stockett, M. H.; Adoui, L.; Anderson, E. K.; Chen, T.; Chesnel, J.-Y.; de Ruette, N.; Gatchell, M.; Giacomozzi, L.; Huber, B. A.; Kulyk, K.; Maclot, S.; Rousseau, P.; Wolf, M.; Zettergen, H.; Schmidt, H. T.; Cederquist, H.

    2015-09-01

    Non-statistical fragmentation processes are important when Polycyclic Aromatic Hydrocarbon (PAH) molecules, fullerenes, or other large molecules collide with atoms at center- of-mass energies from a few tens to a few hundreds of eV. The typical result is the prompt, billiard-ball-like knockout of single atoms (CHx-loss). This is distinct from the well-known statistical fragmentation patterns of these molecules, which are dominated by H- and C2H2-loss for PAHs and C2-loss for fullerenes. We have explored the role of non-statistical fragmentation of PAHs and fullerenes in a series of experimental and theoretical studies. In general, the yield of non-statistical fragments depends sensitively on their stability against secondary statistical fragmentation following knockout.

  8. Large Atomic and Nuclear Three-Body Systems:. Scattering and Binding

    NASA Astrophysics Data System (ADS)

    Tomio, Lauro; Yamashita, M. T.; Frederico, T.

    The universal character of non-relativistic large three-body bosonic systems is addressed, with focus on highly interesting situations that occur in low-energy nuclear and atomic physics. Investigations on the trajectory of the first excited Efimov state, in a renormalized zero-range three-body model for a system with two bound and one virtual two-body subsystems, are reported. The approach is applied to n-n-18C, where the n - n virtual energy and the three-body ground state are kept fixed. It is shown that the real part of the elastic s-wave phase-shift (δ 0R ) presents a zero, or a pole in k \\cot δ 0R , when the system has an Efimov excited or virtual state. A brief discussion is given on the relevance of the approach for ultracold atom physics with tunable scattering lengths.

  9. Large-Area Atomic Oxygen Facility Used to Clean Fire-Damaged Artwork

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon K.; Banks, Bruce A.; Steuber, Thomas J.; Sechkar, Edward A.

    2000-01-01

    In addition to completely destroying artwork, fires in museums and public buildings can soil a displayed artwork with so much accumulated soot that it can no longer be used for study or be enjoyed by the public. In situations where the surface has not undergone extensive charring or melting, restoration can be attempted. However, soot deposits can be very difficult to remove from some types of painted surfaces, particularly when the paint is fragile or flaking or when the top surface of the paint binder has been damaged. Restoration typically involves the use of organic solvents to clean the surface, but these solvents may cause the paint layers to swell or leach out. Also, immersion of the surface or swabbing during solvent cleaning may move or remove pigment through mechanical contact, especially if the fire damage extends into the paint binder. A noncontact technique of removing organic deposits from surfaces was developed out of NASA research on the effects of oxygen atoms on various materials. Atomic oxygen is present in the atmosphere surrounding the Earth at the altitudes where satellites typically orbit. It can react chemically with surface coatings or deposits that contain carbon. In the reaction, the carbon is converted to carbon monoxide and some carbon dioxide. Water vapor is also a byproduct of the reaction if the surface contains carbon-hydrogen bonds. To study this reaction, NASA developed Earth-based facilities to produce atomic oxygen for material exposure and testing. A vacuum facility designed and built by the Electro-Physics Branch of the NASA Glenn Research Center at Lewis Field to provide atomic oxygen over a large area for studying reactions in low Earth orbit has been used to successfully clean several full-size paintings. (This facility can accommodate paintings up to 1.5 by 2.1 m. The atomic oxygen plasma is produced between two large parallel aluminum plates using a radiofrequency power source operating at roughly 400 W. Atomic oxygen is

  10. Large-scale quantum transport calculations for electronic devices with over ten thousand atoms

    NASA Astrophysics Data System (ADS)

    Lu, Wenchang; Lu, Yan; Xiao, Zhongcan; Hodak, Miro; Briggs, Emil; Bernholc, Jerry

    The non-equilibrium Green's function method (NEGF) has been implemented in our massively parallel DFT software, the real space multigrid (RMG) code suite. Our implementation employs multi-level parallelization strategies and fully utilizes both multi-core CPUs and GPU accelerators. Since the cost of the calculations increases dramatically with the number of orbitals, an optimal basis set is crucial for including a large number of atoms in the ``active device'' part of the simulations. In our implementation, the localized orbitals are separately optimized for each principal layer of the device region, in order to obtain an accurate and optimal basis set. As a large example, we calculated the transmission characteristics of a Si nanowire p-n junction. The nanowire is along (110) direction in order to minimize the number dangling bonds that are saturated by H atoms. Its diameter is 3 nm. The length of 24 nm is necessary because of the long-range screening length in Si. Our calculations clearly show the I-V characteristics of a diode, i.e., the current increases exponentially with forward bias and is near zero with backward bias. Other examples will also be presented, including three-terminal transistors and large sensor structures.

  11. High-speed atomic force microscopy for large scan sizes using small cantilevers

    NASA Astrophysics Data System (ADS)

    Braunsmann, Christoph; Schäffer, Tilman E.

    2010-06-01

    We present a high-speed atomic force microscope that exhibits a number of practical advantages over previous designs. Its central component is a high-speed scanner with a maximum scan size of 23 µm × 23 µm and a conveniently large sample stage area (6.5 mm × 6.5 mm). In combination with small cantilevers, image rates of up to 46 images s - 1 in air and 13 images s - 1 in liquid are reached under z-feedback control. By large scan size imaging of collagen fibrils in air, sample velocities of 8.8 mm s - 1 in the xy-direction and 11 mm s - 1 in the z-direction are reached. To provide optimized imaging conditions for both large and small scan sizes, a modular scanner design allows easily exchanging the x- and y-piezos. The scanner is therefore also suited for investigations on the molecular and atomic scale, which is demonstrated by imaging the step dynamics of a calcite surface during dissolution and the hexagonal lattice of a mica surface in liquid.

  12. X-ray crystallography of large RNAs: heavy-atom derivatives by RNA engineering.

    PubMed

    Golden, B L; Gooding, A R; Podell, E R; Cech, T R

    1996-12-01

    For small RNAs, isomorphous heavy-atom derivatives can be obtained by crystallizing synthetic versions that incorporate modified nucleotides such as iodo- or bromouridine. However, such a synthetic approach is not yet feasible for RNAs greater than approximately 40 nt. We have been investigating P4-P6, a 160-nt domain of the self-splicing Tetrahymena intron whose structure was solved recently (Cate JH et al., 1996, Science 273:1678-1685). To incorporate iodouridine, a two-piece RNA was constructed. The 5' segment, containing the majority of the molecule, was transcribed in vitro using a self-processing hammerhead ribozyme to cleave the nascent transcript and give a homogenous 3' end. A synthetic 5-iodouridine-containing RNA corresponding to the remainder of the sequence was then annealed to the transcribed piece of RNA. The resulting RNA appeared structurally and functionally sound as judged by nondenaturing gel electrophoresis and RNA cleavage assays. Four versions of this two-piece system with 5-iodouridine substitutions at different positions crystallized under the same conditions as the native RNA, yielding two useful heavy-atom derivatives of P4-P6. The position of the iodine atoms for the derivatives could be determined in the absence of phase information, and an interpretable electron density map was calculated using only the data from the two iodouridine derivatives. This approach is expected to be readily adaptable to other large, structured RNA molecules. PMID:8972777

  13. Modeling optical properties of silicon clusters by first principles: From a few atoms to large nanocrystals

    SciTech Connect

    Nurbawono, Argo; Liu, Shuanglong; Zhang, Chun

    2015-04-21

    Time dependent density functional tight binding (TDDFTB) method is implemented with sparse matrix techniques and improved parallelization algorithms. The method is employed to calculate the optical properties of various Si nanocrystals (NCs). The calculated light absorption spectra of small Si NCs from TDDFTB were found to be comparable with many body perturbation methods utilizing planewave basis sets. For large Si NCs (more than a thousand atoms) that are beyond the reach of conventional approaches, the TDDFTB method is able to produce reasonable results that are consistent with prior experiments. We also employed the method to study the effects of surface chemistry on the optical properties of large Si NCs. We learned that the optical properties of Si NCs can be manipulated with small molecule passivations such as methyl, hydroxyl, amino, and fluorine. In general, the shifts and profiles in the absorption spectra can be tuned with suitably chosen passivants.

  14. Large-scale synthesis of WSe2 atomic layers on SiO2/Si

    NASA Astrophysics Data System (ADS)

    Cao, Hui-Wen; Zhao, Hai-Ming; Xin, Xin; Shao, Peng-Zhi; Qi, Han-Yu; Jian, Mu-Qiang; Zhang, Ying-Ying; Yang, Yi; Ren, Tian-Ling

    2016-06-01

    We report a systematic study of large-scale growth of high-quality WSe2 atomic layers directly on SiO2/Si substrates using a convenient method. Various parameters, especially growth temperatures, flow rate of carrier gas and tube pressure, are investigated in affecting the properties of as-grown WSe2 flakes in terms of their sizes, shapes and thickness. The pre-annealing step is demonstrated to be a key role in achieving the large-scale growth. Under an optimized condition, the lateral size of triangular single-crystal monolayer WSe2 is up to 30 μm and the area of the monolayer thin film can be up to 0.25 mm2. And some other interesting features, such as nanoflowers, are observed, which are a promising for catalyzing research. Raman spectrum and microphotoluminescence indicate distinct layer dependent efficiency. Auger electron spectroscopy (AES) studies demonstrate the atomic concentration of the as-grown WSe2. Electrical transport further shows that the p-type WSe2 field-effect transistors exhibit excellent electrical properties with carrier mobility of ˜64 cm2ṡV‑1ṡs‑1 and current on/off ratio over 105. These results are comparable to the exfoliated materials.

  15. Seismogenic Cycles, Quartz Microstructures and Localization at the Frictional to Viscous Transition in an Exhumed, Large-Displacement, Seismogenic Strike-Slip Fault

    NASA Astrophysics Data System (ADS)

    Song, W. J.; Johnson, S. E.; Price, N.; Song, B. R.; Gerbi, C. C.; West, D. P., Jr.

    2014-12-01

    The frictional-to-viscous transition (FVT) in the vicinity of seismogenic faults experiences coseismic fracturing/frictional sliding followed by viscous creep during postseismic relaxation. A more complete understanding of these processes at the FVT is important owing to its control over the mechanical decoupling between crustal levels. However, well-preserved microstructural records from this depth are rarely preserved in exhumed faults because of progressive deformation and metamorphism in exhumation. We investigate quartz deformation microstructures from traverses across the Sandhill Corner shear zone, a strand of the Norumbega fault system (an ancient large-displacement, subvertical strike-slip fault system in the northeastern Appalachians) exhumed from FVT depths in order to characterize in greater detail the previously proposed architecture that divides the shear zone into an outer zone, inner zone and core. Trends in quantitative crystallographic preferred orientation (CPO) and misorientation data from electron backscatter diffraction and 2D grain-size distributions confirm finer grain sizes within the inner zone and core, a weak CPO pattern and randomization in the misorientation of randomly selected grain pairs. Additional analyses with finer sample spacing and using fabric intensity indices (J- & M-Index), we show a progressive weakening of the CPO from the outer edges to the core and a decrease in grain size down to an average of 8 μm at the core, an average finer than previously reported. Within the inner zone and core (ca. 30m width), the microstructural parameters are unusual: a weak CPO but a pattern clearly indicative of basal slip. New deformation mechanism maps for different parts of the shear zone suggest deformation near the transition to grain size-sensitive creep. Our data confirms and builds new evidence for the model that during the seismic cycle, quartz grains within the core and inner zone experienced cycles of coseismic microfracture

  16. Measuring vulnerability to disaster displacement

    NASA Astrophysics Data System (ADS)

    Brink, Susan A.; Khazai, Bijan; Power, Christopher; Wenzel, Friedemann

    2015-04-01

    Large scale disasters can cause devastating impacts in terms of population displacement. Between 2008 and 2013, on average 27 million people were displaced annually by disasters (Yonetani 2014). After large events such as hurricane Katrina or the Port-au-Prince earthquake, images of inadequate public shelter and concerns about large scale and often inequitable migration have been broadcast around the world. Population displacement can often be one of the most devastating and visible impacts of a natural disaster. Despite the importance of population displacement in disaster events, measures to understand the socio-economic vulnerability of a community often use broad metrics to estimate the total socio-economic risk of an event rather than focusing on the specific impacts that a community faces in a disaster. Population displacement is complex and multi-causal with the physical impact of a disaster interacting with vulnerability arising from the response, environmental issues (e.g., weather), cultural concerns (e.g., expectations of adequate shelter), and many individual factors (e.g., mobility, risk perception). In addition to the complexity of the causes, population displacement is difficult to measure because of the wide variety of different terms and definitions and its multi-dimensional nature. When we speak of severe population displacement, we may refer to a large number of displaced people, an extended length of displacement or associated difficulties such as poor shelter quality, risk of violence and crime in shelter communities, discrimination in aid, a lack of access to employment or other difficulties that can be associated with large scale population displacement. We have completed a thorough review of the literature on disaster population displacement. Research has been conducted on historic events to understand the types of negative impacts associated with population displacement and also the vulnerability of different groups to these impacts. We

  17. Large-Area Quality Control of Atomically-Thin Layered Materials

    NASA Astrophysics Data System (ADS)

    Nolen, Craig Merten

    Fast progress in chemical vapor deposition of graphene and other quasi-two-dimensional layered materials such as topological insulators call for development of a reliable high-throughput method of layered materials identification and quality control. The number of atomic planes in graphene or other ultra-thin films has to be determined very fast and over large wafer-scale areas. The previously existed methods of accurate counting of the number of atomic planes in few-layer graphene were primarily based on micro-Raman spectroscopy. These methods were local, slow, and could not be scaled up to characterize the whole wafers. In this dissertation research I proposed and developed an automatic approach for graphene inspection over the wafer-size areas. The proposed method can be scaled up for industrial use. It is based on the image processing analysis of the pseudo-color contrasts uniquely assigned to each few-layer graphene region characterized by a specific number of atomic planes. The initial calibration of the technique is performed with the help of micro-Raman spectroscopy. The image processing is also used to account for the lighting non-uniformity of the samples. Implementation of the technique developed in this dissertation research reduces the cost and time required for graphene identification and quality assessment, and can become the next major impetus for practical applications of graphene, few-layer graphene and other atomically-thin films. The technique was tested on mechanically exfoliated graphene and then extended to the chemical-vapor-deposited graphene, and to bismuth telluride topological insulator thin films. The second part of the dissertation research deals with development of the electrostatic transfer process. The investigated approach allows one to transfer the patterned few-layer graphene films controllably to Si3N4 substrates compatible with other materials. The large-area quality control and graphene transfer techniques developed in this

  18. Nonaffine rearrangements of atoms in deformed and quiescent binary glasses

    NASA Astrophysics Data System (ADS)

    Priezjev, Nikolai V.

    2016-08-01

    The influence of periodic shear deformation on nonaffine atomic displacements in an amorphous solid is examined via molecular dynamics simulations. We study the three-dimensional Kob-Andersen binary mixture model at a finite temperature. It is found that when the material is periodically strained, most of the atoms undergo repetitive nonaffine displacements with amplitudes that are broadly distributed. We show that particles with large amplitudes of nonaffine displacements are organized into compact clusters. With increasing strain amplitude, spatial correlations of nonaffine displacements become increasingly long-ranged, although they remain present even in a quiescent system due to thermal fluctuations.

  19. The Enigmatic 2008 Mw 6.9 Iwate-Miyagi Nairiku, Japan, Earthquake: A Large Shallow Thrust Event with Little Surface Displacement and Scant Evidence for Paleoseismic Slip

    NASA Astrophysics Data System (ADS)

    Toda, S.; Maruyama, T.; Yoshimi, M.; Awata, Y.; Kaneda, H.; Yoshioka, T.; Ando, R.

    2008-12-01

    The 14 June 2008 Mw 6.9 Iwate-Miyagi Nairiku earthquake struck the mountainous region in northern Honshu and was accompanied by isolated surface ruptures along ~20 km-long NNE-trend. To understand its relation to the seismogenic faulting at depth, we conducted field investigations immediately after the mainshock, performing detailed mapping and measuring fault displacements using a total station instrument and ground-based LiDAR. More than 12 fault-rupture sites suggest that the total length of the tectonic ground breakage reaches ~20 km. Contractional features such as thrust fault exposures, flexure, tilting, and buckling deformations predominate on the rupture zone, which is consistent with reverse faulting driven by the WNW-ESE compressional stress field in northern Honshu. Shortening as well as vertical displacements were visible on cultural features such as concrete, asphalt paved roads, sidewalks, guardrails, drainage ditches, and rice paddies. Soaked soil underlying paddy fields immediately after rice transplanting worked particularly well to measure such small deformations, separating them into emerged and submerged parts. Amounts of vertical offset and horizontal shortening measured using such cultural piercing points are mostly less than 50 cm, indicating ~1m of net fault slip. Near the southern end of the rupture zone, the fault structure and slip sense become complex and measured offsets are exceptionally large. We found a ~1-km-long E-W-striking continuous rupture with up to 7 m right-lateral and 4 m vertical offsets of a paved road, trails, and rills near the northern rim of the Aratozawa dam reservoir. LiDAR measurements together with our field observations reveal features typical of strike-slip faulting such as mole tracks, fissures, pressure ridges, bulges, tilted trees, and shutter ridges, as well as the offset rills and ridges. The mapped zone of ruptures approximately locates along the central part of the surface projection of an inferred ~40-km

  20. An atomic-absorption method for the determination of gold in large samples of geologic materials

    USGS Publications Warehouse

    VanSickle, Gordon H.; Lakin, Hubert William

    1968-01-01

    A laboratory method for the determination of gold in large (100-gram) samples has been developed for use in the study of the gold content of placer deposits and of trace amounts of gold in other geologic materials. In this method the sample is digested with bromine and ethyl ether, the gold is extracted into methyl isobutyl ketone, and the determination is made by atomicabsorption spectrophotometry. The lower limit of detection is 0.005 part per million in the sample. The few data obtained so far by this method agree favorably with those obtained by assay and by other atomic-absorption methods. About 25 determinations can be made per man-day.

  1. Large-area thermoelectric high-aspect-ratio nanostructures by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Ruoho, Mikko; Juntunen, Taneli; Tittonen, Ilkka

    2016-09-01

    We report on the thermoelectric properties of large-area high-aspect-ratio nanostructures. We fabricate the structures by atomic layer deposition of conformal ZnO thin films on track-etched polycarbonate substrate. The resulting structure consists of ZnO tubules which continue through the full thickness of the substrate. The electrical and thermal properties of the structures are studied both in-plane and out-of-plane. They exhibit very low out-of-plane thermal conductivity down to 0.15 W m‑1 K‑1 while the in-plane sheet resistance of the films was found to be half that of the same film on glass substrate, allowing material-independent doubling of output power of any planar thin-film thermoelectric generator. The wall thickness of the fabricated nanotubes was varied within a range of up to 100 nm. The samples show polycrystalline nature with (002) preferred crystal orientation.

  2. Calculations of atomic sputtering and displacement cross-sections in solid elements by electrons with energies from threshold to 1. 5 MV

    SciTech Connect

    Bradley, C.R.

    1988-12-01

    The kinetics of knock-on collisions of relativistic electrons with nuclei and details of the numerical evaluation of differential, recoil, and total Mott cross-sections are reviewed and discussed. The effects of electron beam induced displacement and sputtering, in the transmission electron microscope (TEM) environment, on microanalysis are analyzed with particular emphasis placed on the removal of material by knock-on sputtering. The mass loss predicted due to transmission knock-on sputtering is significant for many elements under conditions frequently encountered in microanalysis. Total Mott cross-sections are tabulated for all naturally occurring solid elements up to Z = 92 at displacement energies of one, two, four, and five times the sublimation energy and for accelerating voltages accessible in the transmission electron microscope. Fortran source code listings for the calculation of the differential Mott cross-section as a function of electron scattering angle (dMottCS), as a function of nuclear recoil angle (RECOIL), and the total Mott cross-section (TOTCS) are included. 48 refs., 21 figs., 12 tabs.

  3. Epitaxial B-Graphene: Large-Scale Growth and Atomic Structure.

    PubMed

    Usachov, Dmitry Yu; Fedorov, Alexander V; Petukhov, Anatoly E; Vilkov, Oleg Yu; Rybkin, Artem G; Otrokov, Mikhail M; Arnau, Andrés; Chulkov, Evgueni V; Yashina, Lada V; Farjam, Mani; Adamchuk, Vera K; Senkovskiy, Boris V; Laubschat, Clemens; Vyalikh, Denis V

    2015-07-28

    Embedding foreign atoms or molecules in graphene has become the key approach in its functionalization and is intensively used for tuning its structural and electronic properties. Here, we present an efficient method based on chemical vapor deposition for large scale growth of boron-doped graphene (B-graphene) on Ni(111) and Co(0001) substrates using carborane molecules as the precursor. It is shown that up to 19 at. % of boron can be embedded in the graphene matrix and that a planar C-B sp(2) network is formed. It is resistant to air exposure and widely retains the electronic structure of graphene on metals. The large-scale and local structure of this material has been explored depending on boron content and substrate. By resolving individual impurities with scanning tunneling microscopy we have demonstrated the possibility for preferential substitution of carbon with boron in one of the graphene sublattices (unbalanced sublattice doping) at low doping level on the Ni(111) substrate. At high boron content the honeycomb lattice of B-graphene is strongly distorted, and therefore, it demonstrates no unballanced sublattice doping. PMID:26121999

  4. Large extrinsic spin Hall effect in Au-Cu alloys by extensive atomic disorder scattering

    NASA Astrophysics Data System (ADS)

    Zou, L. K.; Wang, S. H.; Zhang, Y.; Sun, J. R.; Cai, J. W.; Kang, S. S.

    2016-01-01

    Spin Hall angle, which denotes the conversion efficiency between spin and charge current, is a key parameter in the pure spin current phenomenon. The search for materials with large spin Hall angle is indeed important for scientific interest and potential application in spintronics. Here the large enhanced spin Hall effect (SHE) of Au-Cu alloy is reported by investigating the spin Seebeck effect, spin Hall anomalous Hall effect, and spin Hall magnetoresistance of the Y3F e5O12 (YIG)/A uxC u1 -x hybrid structure over the full composition. At the near equiatomic Au-Cu composition with maximum atomic disorder scattering, the spin Hall angle of the Au-Cu alloy increases by two to three times together with a moderate spin diffusion length in comparison with Au. The longitudinal spin Seebeck voltage and the spin Hall magnetoresistance ratio also increase by two to three times. More importantly, no evidence of anomalous Hall effect is observed in all YIG/Au-Cu samples, in contrast to the cases of other giant SHE materials Pt(Pd), Ta, and W. This behavior makes Au-Cu free from any suspicion of the magnetic proximity effect involved in the hybrid structure, and thus the Au-Cu alloy can be an ideal material for pure spin current study.

  5. Hydrogen atom temperature measured with wavelength-modulated laser absorption spectroscopy in large scale filament arc negative hydrogen ion source

    SciTech Connect

    Nakano, H. Goto, M.; Tsumori, K.; Kisaki, M.; Ikeda, K.; Nagaoka, K.; Osakabe, M.; Takeiri, Y.; Kaneko, O.; Nishiyama, S.; Sasaki, K.

    2015-04-08

    The velocity distribution function of hydrogen atoms is one of the useful parameters to understand particle dynamics from negative hydrogen production to extraction in a negative hydrogen ion source. Hydrogen atom temperature is one of the indicators of the velocity distribution function. To find a feasibility of hydrogen atom temperature measurement in large scale filament arc negative hydrogen ion source for fusion, a model calculation of wavelength-modulated laser absorption spectroscopy of the hydrogen Balmer alpha line was performed. By utilizing a wide range tunable diode laser, we successfully obtained the hydrogen atom temperature of ∼3000 K in the vicinity of the plasma grid electrode. The hydrogen atom temperature increases as well as the arc power, and becomes constant after decreasing with the filling of hydrogen gas pressure.

  6. RTV 21 Displacements

    SciTech Connect

    Kurita, C.H.; /Fermilab

    1987-02-04

    A seal is needed for the cover of the Nitrogen Test Vessel in order to prevent leakage of the N{sub 2} gas. This seal is to be molded out of RTV 21. In this experiment, the Modulus of Elasticity of the RTV was sought after, and the displacements of the RTV due to various stresses were measured to see if they were large enough to provide a tight seal between the vessel and its cover.

  7. Photoresponse properties of large-area MoS{sub 2} atomic layer synthesized by vapor phase deposition

    SciTech Connect

    Luo, Siwei; Qi, Xiang E-mail: jxzhong@xtu.edu.cn; Ren, Long; Hao, Guolin; Fan, Yinping; Liu, Yundan; Han, Weijia; Zang, Chen; Li, Jun; Zhong, Jianxin E-mail: jxzhong@xtu.edu.cn

    2014-10-28

    Photoresponse properties of a large area MoS{sub 2} atomic layer synthesized by vapor phase deposition method without any catalyst are studied. Scanning electron microscopy, atomic force microscopy, Raman spectrum, and photoluminescence spectrum characterizations confirm that the two-dimensional microstructures of MoS{sub 2} atomic layer are of high quality. Photoelectrical results indicate that the as-prepared MoS{sub 2} devices have an excellent sensitivity and a good reproducibility as a photodetector, which is proposed to be ascribed to the potential-assisted charge separation mechanism.

  8. Photoresponse properties of large-area MoS2 atomic layer synthesized by vapor phase deposition

    NASA Astrophysics Data System (ADS)

    Luo, Siwei; Qi, Xiang; Ren, Long; Hao, Guolin; Fan, Yinping; Liu, Yundan; Han, Weijia; Zang, Chen; Li, Jun; Zhong, Jianxin

    2014-10-01

    Photoresponse properties of a large area MoS2 atomic layer synthesized by vapor phase deposition method without any catalyst are studied. Scanning electron microscopy, atomic force microscopy, Raman spectrum, and photoluminescence spectrum characterizations confirm that the two-dimensional microstructures of MoS2 atomic layer are of high quality. Photoelectrical results indicate that the as-prepared MoS2 devices have an excellent sensitivity and a good reproducibility as a photodetector, which is proposed to be ascribed to the potential-assisted charge separation mechanism.

  9. A thermal modelling of displacement cascades in uranium dioxide

    NASA Astrophysics Data System (ADS)

    Martin, G.; Garcia, P.; Sabathier, C.; Devynck, F.; Krack, M.; Maillard, S.

    2014-05-01

    The space and time dependent temperature distribution was studied in uranium dioxide during displacement cascades simulated by classical molecular dynamics (MD). The energy for each simulated radiation event ranged between 0.2 keV and 20 keV in cells at initial temperatures of 700 K or 1400 K. Spheres into which atomic velocities were rescaled (thermal spikes) have also been simulated by MD to simulate the thermal excitation induced by displacement cascades. Equipartition of energy was shown to occur in displacement cascades, half of the kinetic energy of the primary knock-on atom being converted after a few tenths of picoseconds into potential energy. The kinetic and potential parts of the system energy are however subjected to little variations during dedicated thermal spike simulations. This is probably due to the velocity rescaling process, which impacts a large number of atoms in this case and would drive the system away from a dynamical equilibrium. This result makes questionable MD simulations of thermal spikes carried out up to now (early 2014). The thermal history of cascades was compared to the heat equation solution of a punctual thermal excitation in UO2. The maximum volume brought to a temperature above the melting temperature during the simulated cascade events is well reproduced by this simple model. This volume eventually constitutes a relevant estimate of the volume affected by a displacement cascade in UO2. This definition of the cascade volume could also make sense in other materials, like iron.

  10. Large-area thermoelectric high-aspect-ratio nanostructures by atomic layer deposition.

    PubMed

    Ruoho, Mikko; Juntunen, Taneli; Tittonen, Ilkka

    2016-09-01

    We report on the thermoelectric properties of large-area high-aspect-ratio nanostructures. We fabricate the structures by atomic layer deposition of conformal ZnO thin films on track-etched polycarbonate substrate. The resulting structure consists of ZnO tubules which continue through the full thickness of the substrate. The electrical and thermal properties of the structures are studied both in-plane and out-of-plane. They exhibit very low out-of-plane thermal conductivity down to 0.15 W m(-1) K(-1) while the in-plane sheet resistance of the films was found to be half that of the same film on glass substrate, allowing material-independent doubling of output power of any planar thin-film thermoelectric generator. The wall thickness of the fabricated nanotubes was varied within a range of up to 100 nm. The samples show polycrystalline nature with (002) preferred crystal orientation. PMID:27454037

  11. A large-deformation thin plate theory with application to one-atom-thick layers

    NASA Astrophysics Data System (ADS)

    Delfani, M. R.; Shodja, H. M.

    2016-02-01

    Nowadays, two-dimensional materials due to their vast engineering and biomedical applications have been the focus of many researches. The present paper proposes a large-deformation theory for thin plates with application to one-atom-thick layers (OATLs). The deformation is formulated exactly in the mathematical framework of Lagrangian description. In particular, an exact finite strain analysis is given - in addition to the usual strain tensor associated to the middle surface, the second and third fundamental forms of the middle surface of the deformed thin plate are also maintained in the analysis. Exact closed-form solutions for a uniaxially curved thin plate due to pure bending in one case and due to a combination of vertical and horizontal loading in another are obtained. As a special case of the latter problem, the exact solution for the plane-strain bulge test of thin plates is derived. Subsequently, the approximation of Vlassak and Nix [Vlassak, J.J., Nix, W.D., 1992. J. Mater. Res., 7(12), 3242-3249] for the load-deflection equation is recovered. The given numerical results are devoted to graphene as the most well-known OATL.

  12. Fabrication of large scale nanostructures based on a modified atomic force microscope nanomechanical machining system.

    PubMed

    Hu, Z J; Yan, Y D; Zhao, X S; Gao, D W; Wei, Y Y; Wang, J H

    2011-12-01

    The atomic force microscope (AFM) tip-based nanomechanical machining has been demonstrated to be a powerful tool for fabricating complex 2D∕3D nanostructures. But the machining scale is very small, which holds back this technique severely. How to enlarge the machining scale is always a major concern for the researches. In the present study, a modified AFM tip-based nanomechanical machining system is established through combination of a high precision X-Y stage with the moving range of 100 mm × 100 mm and a commercial AFM in order to enlarge the machining scale. It is found that the tracing property of the AFM system is feasible for large scale machining by controlling the constant normal load. Effects of the machining parameters including the machining direction and the tip geometry on the uniform machined depth with a large scale are evaluated. Consequently, a new tip trace and an increasing load scheme are presented to achieve a uniform machined depth. Finally, a polymer nanoline array with the dimensions of 1 mm × 0.7 mm, the line density of 1000 lines/mm and the average machined depth of 150 nm, and a 20 × 20 polymer square holes array with the scale of 380 μm × 380 μm and the average machined depth of 250 nm are machined successfully. The uniform of the machined depths for all the nanostructures is acceptable. Therefore, it is verified that the AFM tip-based nanomechanical machining method can be used to machine millimeter scale nanostructures. PMID:22225244

  13. Large fluctuations in the disassembly rate of microtubules revealed by atomic force microscopy.

    PubMed

    Thomson, Neil H; Kasas, Sandor; Riederer, Beat M; Catsicas, Stefan; Dietler, Giovanni; Kulik, Andrzej J; Forró, László

    2003-01-01

    Atomic force microscopy (AFM) in situ has been used to observe the cold disassembly dynamics of microtubules at a previously unrealised spatial resolution. Microtubules either electrostatically or covalently bound to aminosilane surfaces disassembled at room temperature under buffer solutions with no free tubulin present. This process was followed by taking sequential tapping-mode AFM images and measuring the change in the microtubule end position as a function of time, with an spatial accuracy down to +/-20nm and a temporal accuracy of +/-1s. As well as giving average disassembly rates on the order of 1-10 tubulin monomers per second, large fluctuations in the disassembly rate were revealed, indicating that the process is far from smooth and linear under these experimental conditions. The surface bound rates measured here are comparable to the rates for GMPCPP-tubulin microtubules free in solution, suggesting that inhibition of tubulin curvature through steric hindrance controls the average, relatively low disassembly rate. The large fluctuations in this rate are thought to be due to multiple pathways in the kinetics of disassembly with differing rate constants and/or stalling due to defects in the microtubule lattice. Microtubules that were covalently bound to the surface left behind the protofilaments covalently cross-linked to the aminosilane via glutaraldehyde during the disassembly process. Further work is needed to quantitatively assess the effects of surface binding on protofibril disassembly rates, reveal any differences in disassembly rates between the plus and minus ends and to enable assembly as well as disassembly to be imaged in the microscope fluid cell in real-time. PMID:12801676

  14. Finding the minimum-energy atomic configuration in large multi-atom structures: Genetic Algorithm versus the Virtual-Atom Approach

    NASA Astrophysics Data System (ADS)

    D'Avezac, Mayeul; Zunger, Alex

    2007-03-01

    In many problems in molecular and solid state structures one needs to determine the energy-minimizing decoration of sites by different atom-types (i. e.configuration). The sheer size of this configurational space can be horrendous even if the underlying lattice-type is known. The ab-initio total-energy surface for different (relaxed) configurations can often be parameterized by a spin-like Hamiltonian (Cluster-Expansion) with discrete spin -variables denoting the type of atom occupying each site. We compare two search strategies for the energy-minimizing configuration: (i) A discrete-variable genetic-algorithm approach( S. V. Dudiy and A. Zunger, PRL 97, 046401 (2006) ) and (ii) a continuous-variable approach (M. Wang et al, J. Am. Chem. Soc. 128, 3228 (2006) ) where the discrete-spin functional is mapped onto a continuous-spin functional (virtual atoms) and the search is guided by local gradients with respect to each spin. We compare their efficiency at locating the ground-state configurations of fcc Au-Pd Alloy in terms of number of calls to the functional. We show that a GA approach with diversity-enhancing constraints and reciprocal-space mating easily outperforms the VA approach.

  15. Lateral displacement and rotational displacement sensor

    DOEpatents

    Duden, Thomas

    2014-04-22

    A position measuring sensor formed from opposing sets of capacitor plates measures both rotational displacement and lateral displacement from the changes in capacitances as overlapping areas of capacitors change. Capacitances are measured by a measuring circuit. The measured capacitances are provided to a calculating circuit that performs calculations to obtain angular and lateral displacement from the capacitances measured by the measuring circuit.

  16. Origin of Perpendicular Magnetic Anisotropy and Large Orbital Moment in Fe Atoms on MgO.

    PubMed

    Baumann, S; Donati, F; Stepanow, S; Rusponi, S; Paul, W; Gangopadhyay, S; Rau, I G; Pacchioni, G E; Gragnaniello, L; Pivetta, M; Dreiser, J; Piamonteze, C; Lutz, C P; Macfarlane, R M; Jones, B A; Gambardella, P; Heinrich, A J; Brune, H

    2015-12-01

    We report on the magnetic properties of individual Fe atoms deposited on MgO(100) thin films probed by x-ray magnetic circular dichroism and scanning tunneling spectroscopy. We show that the Fe atoms have strong perpendicular magnetic anisotropy with a zero-field splitting of 14.0±0.3  meV/atom. This is a factor of 10 larger than the interface anisotropy of epitaxial Fe layers on MgO and the largest value reported for Fe atoms adsorbed on surfaces. The interplay between the ligand field at the O adsorption sites and spin-orbit coupling is analyzed by density functional theory and multiplet calculations, providing a comprehensive model of the magnetic properties of Fe atoms in a low-symmetry bonding environment. PMID:26684139

  17. The influence of embedded atoms, molecules, and clusters on the lifetimes of electron bubbles in large 4He droplets

    NASA Astrophysics Data System (ADS)

    Fárník, Michal; Toennies, J. Peter

    2003-03-01

    The lifetimes of electrons injected into large (≈106atoms) superfluid 4He droplets have been measured in the presence of different prior embedded rare gas atoms, their clusters, and the molecules O2, H2O, and SF6. For the light rare gas atoms Ne and Ar the lifetimes of about 6ṡ10-2 s, found previously for pure droplets, are reduced to between 1-2ṡ10-2 s. Single molecules with large electron affinities, such as SF6 and O2 and small clusters of H2O lead to a significant increase in the lifetimes. In the case of Kr and Xe, larger clusters with n¯>14 are needed before the lifetimes increase. A simple model, which takes account of the energy levels occupied by the electrons in the corresponding molecules or the clusters, assumed to be solid, can qualitatively explain the observations.

  18. Lateral tip control effects in critical dimension atomic force microscope metrology: the large tip limit

    NASA Astrophysics Data System (ADS)

    Dixson, Ronald G.; Orji, Ndubuisi G.; Goldband, Ryan S.

    2016-01-01

    Sidewall sensing in critical dimension atomic force microscopes (CD-AFMs) usually involves continuous lateral dithering of the tip or the use of a control algorithm and fast response piezoactuator to position the tip in a manner that resembles touch-triggering of coordinate measuring machine probes. All methods of tip position control, however, induce an effective tip width that may deviate from the actual geometrical tip width. Understanding the influence and dependence of the effective tip width on the dither settings and lateral stiffness of the tip can improve the measurement accuracy and uncertainty estimation for CD-AFM measurements. Since CD-AFM typically uses tips that range from 15 to 850 nm in geometrical width, the behavior of effective tip width throughout this range should be understood. The National Institute of Standards and Technology (NIST) has been investigating the dependence of effective tip width on the dither settings and lateral stiffness of the tip, as well as the possibility of material effects due to sample composition. For tip widths of 130 nm and lower, which also have lower lateral stiffness, the response of the effective tip width to lateral dither is greater than for larger tips. However, we have concluded that these effects will not generally result in a residual bias, provided that the tip calibration and sample measurement are performed under the same conditions. To confirm that our prior conclusions about the dependence of effective tip width on lateral stiffness are valid for large CD tips, we recently performed experiments using a very large non-CD tip with an etched plateau of ˜2-μm width. The effective lateral stiffness of these tips is at least 20 times greater than typical CD-AFM tips, and these results supported our prior conclusions about the expected behavior for larger tips. The bottom-line importance of these latest observations is that we can now reasonably conclude that a dither slope of 3 nm/V is the baseline

  19. Toward accurate thermochemical models for transition metals : G3large basis sets for atoms Sc-Zn.

    SciTech Connect

    Mayhall, N. J.; Raghavachari, K.; Redfern, P. C.; Curtiss, L. A.; Rassolov, V.; Indiana Univ.; Univ. of South Carolina

    2008-04-01

    An augmented valence triple-zeta basis set, referred to as G3Large, is reported for the first-row transition metal elements Sc through Zn. The basis set is constructed in a manner similar to the G3Large basis set developed previously for other elements (H-Ar, K, Ca, Ga-Kr) and used as a key component in Gaussian-3 theory. It is based on a contraction of a set of 15s13p5d Gaussian primitives to 8s7p3d, and also includes sets of f and g polarization functions, diffuse spd functions, and core df polarization functions. The basis set is evaluated with triples-augmented coupled cluster [CCSD(T)] and Brueckner orbital [BD(T)] methods for a small test set involving energies of atoms, atomic ions, and diatomic hydrides. It performs well for the low-lying s{yields}d excitation energies of atoms, atomic ionization energies, and the dissociation energies of the diatomic hydrides. The Brueckner orbital-based BD(T) method performs substantially better than Hartree-Fock-based CCSD(T) for molecules such as NiH, where the starting unrestricted Hartree-Fock wavefunction suffers from a high degree of spin contamination. Comparison with available data for geometries of transition metal hydrides also shows good agreement. A smaller basis set without core polarization functions, G3MP2Large, is also defined.

  20. Total displacement functions for SiC

    NASA Astrophysics Data System (ADS)

    Weber, W. J.; Williford, R. E.; Sickafus, K. E.

    1997-04-01

    Numerical solutions for the displacement functions in SiC are determined from the coupled integro-differential equations governing the total number of type- j atoms displaced in the collision cascade initiated by a primary knock-on atom (PKA) of type- i and energy E. Atomic scattering cross sections based on either the inverse power law screening potentials or the Ziegler, Biersack, and Littmark (ZBL) universal screening potential are used in the calculation of the displacement functions. The electronic stopping powers used in the calculations are either derived from the LSS and Bethe-Bloch theories or generated from the SRIM-96 electronic stopping power data base. The displacement functions determined using LSS/Bethe-Bloch electronic stopping powers are 25 to 100% larger than the displacement functions determined using the electronic stopping powers generated by SRIM-96. The total number of displaced atoms determined numerically for each PKA type, based on ZBL scattering cross sections and SRIM-96 electronic stopping powers, is in excellent agreement, over the entire range of PKA energies (10 eV to 10 MeV), with the total number of displacements determined by full cascade Monte Carlo simulations using the TRIM code in SRIM-96.

  1. Simulations of threshold displacement in beryllium

    NASA Astrophysics Data System (ADS)

    Jackson, Matthew L.; Fossati, Paul C. M.; Grimes, Robin W.

    2016-07-01

    Atomic scale molecular dynamics simulations of radiation damage have been performed on beryllium. Direct threshold displacement simulations along a geodesic projection of directions were used to investigate the directional dependence with a high spatial resolution. It was found that the directionally averaged probability of displacement increases from 0 at 35 eV, with the energy at which there is a 50% chance of a displacement occurring is 70 eV and asymptotically approaching 1 for higher energies. This is, however, strongly directionally dependent with a 50% probability of displacement varying from 35 to 120 eV, with low energy directions corresponding to the nearest neighbour directions. A new kinetic energy dependent expression for the average maximum displacement of an atom as a function of energy is derived which closely matches the simulated data.

  2. Method for preparing ultraflat, atomically perfect areas on large regions of a crystal surface by heteroepitaxy deposition

    SciTech Connect

    El Gabaly, Farid; Schmid, Andreas K.

    2013-03-19

    A novel method of forming large atomically flat areas is described in which a crystalline substrate having a stepped surface is exposed to a vapor of another material to deposit a material onto the substrate, which material under appropriate conditions self arranges to form 3D islands across the substrate surface. These islands are atomically flat at their top surface, and conform to the stepped surface of the substrate below at the island-substrate interface. Thereafter, the deposited materials are etched away, in the etch process the atomically flat surface areas of the islands transferred to the underlying substrate. Thereafter the substrate may be cleaned and annealed to remove any remaining unwanted contaminants, and eliminate any residual defects that may have remained in the substrate surface as a result of pre-existing imperfections of the substrate.

  3. Large perpendicular magnetic anisotropy of single Co atom on MgO monolayer: A first-principles study

    SciTech Connect

    Shao, Bin; Shi, Wu-Jun; Feng, Min; Zuo, Xu

    2015-05-07

    Realizing the magnetic bit with a single atom is the ultimate goal for magnetic storage. Based on density functional theory, the magnetic anisotropy (MA) of single Co atom on MgO monolayer has been investigated. Results show that this two dimensional system possesses a large perpendicular MA, about 5.8 meV per Co atom. Besides, there exists remarkable unquenched orbital moments for different magnetization directions, which can be attributed to the reduction of coordination number in two dimensional system and is responsible for the enhanced MA. The Bloch pseudo-wavefunction and band structure of Co d-orbitals have been calculated to elucidate the origin of the perpendicular MA.

  4. Stabilization of a laser on a large-detuned atomic-reference frequency by resonant interferometry

    NASA Astrophysics Data System (ADS)

    Barboza, Priscila M. T.; Nascimento, Guilherme G.; Araújo, Michelle O.; da Silva, Cícero M.; Cavalcante, Hugo L. D. de S.; Oriá, Marcos; Chevrollier, Martine; Passerat de Silans, Thierry

    2016-04-01

    We report a simple technique for stabilization of a laser frequency at the wings of an atomic resonance. The reference signal used for stabilization issues from interference effects obtained in a low-quality cavity filled with a resonant atomic vapour. For a frequency detuned 2.6 GHz from the 133Cs D2 6S{}1/2 F = 4 to 6P{}3/2 F’ = 5 transition, the fractional frequency Allan deviation is 10-8 for averaging times of 300 s, corresponding to a frequency deviation of 4 MHz. Adequate choice of the atomic density and of the cell thickness allows locking the laser at detunings larger than 10 GHz. Such a simple technique does not require magnetic fields or signal modulation.

  5. Crystal structure and thermoelectric properties of clathrate, Ba{sub 8}Ni{sub 3.5}Si{sub 42.0}: Small cage volume and large disorder of the guest atom

    SciTech Connect

    Roudebush, John H.; Orellana, Mike; Bux, Sabah

    2012-08-15

    Samples with the type-I clathrate composition Ba{sub 8}Ni{sub x}Si{sub 46-x} have been synthesized and their structure and thermoelectric properties characterized. Microprobe analysis indicates the Ni incorporation to be 2.62{<=}x{<=}3.53. The x=3.5 phase crystallizes in the type-I clathrate structure (space group: Pm-3n) with a lattice parameter of 10.2813(3) A. The refined composition was Ba{sub 8}Ni{sub 3.5}Si{sub 42.0}, with small vacancies, 0.4 and 0.5 atoms per formula unit, at the 2a and 6c sites, respectively. The position of the Ba2 atom in the large cage was modeled using a 4-fold split position (24j site), displaced 0.18 A from the cage center (6d site). The volume of the large cage is calculated to be 146 A{sup 3}, smaller than other clathrates with similar cation displacement. The sample shows n-type behavior with a maximum of -50 {mu}V/K at 823 K above which the Seebeck coefficient decreases, suggesting mixed carriers. Lattice thermal conductivity, {kappa}{sub l}, is 55 mW/K above 600 K. - Graphical abstract: Seebeck coefficient and resistivity of the type-I clathrate Ba{sub 8}Ni{sub 3.5}Si{sub 41.0}. Structure show's large displacement of the Ba cation in the large cage (6c site). Highlights: Black-Right-Pointing-Pointer Crystal structure of the Ba{sub 8}Ni{sub 3.5}Si{sub 41.0} reported. Black-Right-Pointing-Pointer Vacancies at the 2a and 6c sites. Black-Right-Pointing-Pointer Large disorder of Ba guest atom, 0.18 A from cage center. Black-Right-Pointing-Pointer Structure is compared to Ba{sub 8}Si{sub 46} and other type-I clathrates. Black-Right-Pointing-Pointer Max Seebeck of -50.7 {mu}V/C at 798.4 K, thermal conductivity {approx}55 mW/K.

  6. Large-Scale Atomistic Simulations of Solid State Materials -- Modeling Many Millions of Atoms on Parallel Computers

    NASA Astrophysics Data System (ADS)

    Vashishta, Priya

    2000-03-01

    Structural and dynamical correlations including crack propagation and fracture in nanophase materials, atomic level stresses in nanopixels, nanoindentation in crystalline and amorphous materials, and dynamics of oxidation in metallic nanoparticles will be discussed using large-scale atomistic simulations. Multiresolution molecular-dynamics (MRMD) approach for multimillion atom simulations has been used to carry out the 10-100 million atom simulations on a variety of parallel computer architectures including Cray T3E, SGI Origin, IBM SP, and large workstation clusters. Issues related to matching of length scales to carry out seamless simulations of electronic, atomic and continuum degrees of freedom will also be briefly discussed. Research presented in this talk is carried out in collaboration with Martina E. Bachlechner, Timothy Campbell, Ingvar Ebbsjo, Rajiv K. Kalia, Hideaki Kikuchi, Sanjay Kodiyalam, Elefterios Lidorikis, Anupam Madhukar, Aiichiro Nakano, Shuji Ogata, Subhash Saini, Fuyuki Shimojo, and Phillip Walsh. Research supported by the US DOE, NSF, AFOSR, ARO, USC-LSU MURI (DARPA & AFOSR), NASA, and LEQSF

  7. Quantitative spectroscopy of hot stars: accurate atomic data applied on a large scale as driver of recent breakthroughs

    NASA Astrophysics Data System (ADS)

    Przybilla, Norbert; Schaffenroth, Veronika; Nieva, Maria-Fernanda

    2015-08-01

    OB-type stars present hotbeds for non-LTE physics because of their strong radiation fields that drive the atmospheric plasma out of local thermodynamic equilibrium. We report on recent breakthroughs in the quantitative analysis of the optical and UV-spectra of OB-type stars that were facilitated by application of accurate and precise atomic data on a large scale. An astophysicist's dream has come true, by bringing observed and model spectra into close match over wide parts of the observed wavelength ranges. This facilitates tight observational constraints to be derived from OB-type stars for wide applications in astrophysics. However, despite the progress made, many details of the modelling may be improved further. We discuss atomic data needs in terms of laboratory measurements and also ab-initio calculations. Particular emphasis is given to quantitative spectroscopy in the near-IR, which will be in focus in the era of the upcoming extremely large telescopes.

  8. The case for character displacement in plants

    PubMed Central

    Beans, Carolyn M

    2014-01-01

    The evidence for character displacement as a widespread response to competition is now building. This progress is largely the result of the establishment of rigorous criteria for demonstrating character displacement in the animal literature. There are, however, relatively few well-supported examples of character displacement in plants. This review explores the potential for character displacement in plants by addressing the following questions: (1) Why aren't examples of character displacement in plants more common? (2) What are the requirements for character displacement to occur and how do plant populations meet those requirements? (3) What are the criteria for testing the pattern and process of character displacement and what methods can and have been used to address these criteria in the plant literature? (4) What are some additional approaches for studying character displacement in plants? While more research is needed, the few plant systems in which character displacement hypotheses have been rigorously tested suggest that character displacement may play a role in shaping plant communities. Plants are especially amenable to character displacement studies because of the experimental ease with which they can be used in common gardens, selection analyses, and breeding designs. A deeper investigation of character displacement in plants is critical for a more complete understanding of the ecological and evolutionary processes that permit the coexistence of plant species. PMID:24683467

  9. BLOCK DISPLACEMENT METHOD FIELD DEMONSTRATION AND SPECIFICATIONS

    EPA Science Inventory

    The Block Displacement technique has been developed as a remedial action method for isolating large tracks of ground contaminated by hazardous waste. The technique places a low permeability barrier around and under a large block of contaminated earth. The Block Displacement proce...

  10. GRASP92: a package for large-scale relativistic atomic structure calculations

    NASA Astrophysics Data System (ADS)

    Parpia, F. A.; Froese Fischer, C.; Grant, I. P.

    2006-12-01

    Program summaryTitle of program: GRASP92 Catalogue identifier: ADCU_v1_1 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADCU_v1_1 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions: no Programming language used: Fortran Computer: IBM POWERstation 320H Operating system: IBM AIX 3.2.5+ RAM: 64M words No. of lines in distributed program, including test data, etc.: 65 224 No of bytes in distributed program, including test data, etc.: 409 198 Distribution format: tar.gz Catalogue identifier of previous version: ADCU_v1_0 Journal reference of previous version: Comput. Phys. Comm. 94 (1996) 249 Does the new version supersede the previous version?: Yes Nature of problem: Prediction of atomic spectra—atomic energy levels, oscillator strengths, and radiative decay rates—using a 'fully relativistic' approach. Solution method: Atomic orbitals are assumed to be four-component spinor eigenstates of the angular momentum operator, j=l+s, and the parity operator Π=βπ. Configuration state functions (CSFs) are linear combinations of Slater determinants of atomic orbitals, and are simultaneous eigenfunctions of the atomic electronic angular momentum operator, J, and the atomic parity operator, P. Lists of CSFs are either explicitly prescribed by the user or generated from a set of reference CSFs, a set of subshells, and rules for deriving other CSFs from these. Approximate atomic state functions (ASFs) are linear combinations of CSFs. A variational functional may be constructed by combining expressions for the energies of one or more ASFs. Average level (AL) functionals are weighted sums of energies of all possible ASFs that may be constructed from a set of CSFs; the number of ASFs is then the same as the number, n, of CSFs. Optimal level (OL) functionals are weighted sums of energies of some subset of ASFs; the GRASP92 package is optimized for this latter class of functionals. The composition of an ASF in terms

  11. Large cross section for super energy transfer from hyperthermal atoms to ambient molecules

    NASA Astrophysics Data System (ADS)

    Ma, Jianqiang; Wilhelm, Michael J.; Smith, Jonathan M.; Dai, Hai-Lung

    2016-04-01

    The experimentally measured cross section for super energy transfer collisions between a hyperthermal H atom and an ambient molecule is presented here. This measurement substantiates an emerging energy transfer mechanism with significant cross section, whereby a major fraction of atomic translational energy is converted into molecular vibrational energy through a transient collision-induced reactive complex. Specifically, using nanosecond time-resolved infrared emission spectroscopy, it is revealed that collisions between hyperthermal hydrogen atoms (with 59 kcal/mol of kinetic energy) and ambient SO2 result in the production of vibrationally highly excited SO2 with >14 000 cm-1 of internal energy. The lower limit of the cross section for this super energy transfer process is determined to be 0.53 ±0.05 Å2, i.e., 2% of all hard-sphere collisions. This cross section is orders of magnitude greater than that predicted by the exponential energy gap law, which is commonly used for describing collisional energy transfer through repulsive interactions.

  12. Gas Atomization Precursor Powder Approach for Simplified Large-Scale Production of Oxide Dispersion

    SciTech Connect

    Meyer, John; Anderson, Iver; Rieken, Joel; Byrd, David

    2011-04-01

    Oxide dispersion strengthened (ODS) Ni-based alloys show promise for future energy applications that require high-temperature and oxidation resistant properties. Gas atomization reaction synthesis (GARS), with a mixed (Ar/O{sub 2}) atomization gas, is being developed as a simplified route for producing ODS precursor powders. Internal oxidation studies determined Ni-Cr-Y-(Hf or Ti) containing systems are suitable for production of ODS alloys via hot consolidation, which is used to encourage oxygen exchange between the less stable surface oxide phase and reactive alloying elements, resulting in highly stable nano-metric dispersoid formation. Size control of powders is key to optimizing microstructural and strengthening features. Aspiration and, previously, water modeling experiments were used to develop atomization process parameters that encourage controlled powder production while maintaining reduced operating costs when implemented on an industrial scale. For an increase in pour tube extension: aspiration base pressure at any given operating pressure was found to decrease while wake closure pressure was found to increase. Aspiration hysteresis was observed as recorded previously in the literature. Light emission was observed above wake closure pressures.

  13. Nano-scale displacement sensing based on van der Waals interactions

    NASA Astrophysics Data System (ADS)

    Hu, Lin; Zhao, Jin; Yang, Jinlong

    2015-05-01

    We propose that a nano-scale displacement sensor with high resolution in weak-force systems can be realized based on vertically stacked two-dimensional (2D) atomic corrugated layer materials bound through van der Waals (vdW) interactions. Using first-principles calculations, we found that the electronic structures of bi-layer blue phosphorus (BLBP) vary appreciably with lateral and vertical interlayer displacements. The variation of the electronic structure is attributed to the change of the interlayer distance dz for both the lateral and vertical displacement. For lateral displacement, the change of dz is induced by atomic layer corrugation. Despite the different stacking configurations of BLBP, we find that the change of the indirect band gap is proportional to dz-2. Furthermore, this dz-2 dependence is found to be applicable to other graphene-like corrugated bi-layer materials such as MoS2. BLBP represents a large family of bi-layer 2D atomic corrugated materials for which the electronic structure is sensitive to the interlayer vertical and lateral displacement, and thus could be used for a nano-scale displacement sensor. This can be done by monitoring the tunable electronic structure using absorption spectroscopy. Because this type of sensor is established on atomic layers coupled through vdW interactions, it provides unique applications in the measurements of nano-scale displacement induced by tiny external forces.We propose that a nano-scale displacement sensor with high resolution in weak-force systems can be realized based on vertically stacked two-dimensional (2D) atomic corrugated layer materials bound through van der Waals (vdW) interactions. Using first-principles calculations, we found that the electronic structures of bi-layer blue phosphorus (BLBP) vary appreciably with lateral and vertical interlayer displacements. The variation of the electronic structure is attributed to the change of the interlayer distance dz for both the lateral and vertical

  14. Low photon scattering rates and large optical depths of atoms in donut modes of hollow core optical fibers

    NASA Astrophysics Data System (ADS)

    Pechkis, Joseph A.; Fatemi, Fredrik K.

    2012-06-01

    We have guided cold rubidium atoms in blue-detuned hollow optical modes of a hollow fiber. These higher order modes allow large optical depth, low scattering rates, and efficient use of guide laser power. Atoms are transported through a 3-cm-long hollow fiber with a 100 micron diameter using the first three optical modes of the fiber. We compare guiding properties in the red-detuned, fundamental HE11 mode with the blue-detuned TE01 (first order) and HE12 (second order) modes. Using guide laser powers below 50 mW and detunings below 1.5 nm, we have directly measured recoil scattering rates in the three different guides and found that atoms in the HE12 mode typically have a 10x lower recoil scattering rate compared to the red-detuned HE11 mode for equal guide peak intensity. Furthermore, we have observed optical depths of ˜20 for the blue-detuned guides with recoil scattering rates below 10 Hz. We will discuss our ongoing experiments using the atoms in these guides. This work supported by the Office of Naval Research and the Defense Advanced Research Projects Agency.

  15. Job Displacement Among Single Mothers:

    PubMed Central

    Brand, Jennie E.; Thomas, Juli Simon

    2015-01-01

    Given the recent era of economic upheaval, studying the effects of job displacement has seldom been so timely and consequential. Despite a large literature associating displacement with worker well-being, relatively few studies focus on the effects of parental displacement on child well-being, and fewer still focus on implications for children of single parent households. Moreover, notwithstanding a large literature on the relationship between single motherhood and children’s outcomes, research on intergenerational effects of involuntary employment separations among single mothers is limited. Using 30 years of nationally representative panel data and propensity score matching methods, we find significant negative effects of job displacement among single mothers on children’s educational attainment and social-psychological well-being in young adulthood. Effects are concentrated among older children and children whose mothers had a low likelihood of displacement, suggesting an important role for social stigma and relative deprivation in the effects of socioeconomic shocks on child well-being. PMID:25032267

  16. Large-scale circulation of atomic oxygen in the MLT region

    NASA Astrophysics Data System (ADS)

    Shepherd, G.; Liu, G.; Roble, R.

    The atomic oxygen green line airglow at 557.7 nm, originating from the O(1S) level, has a long history of observation, beginning with John Strutt (Lord Rayleigh IV). He drew attention to its variability, a topic that has puzzled successive investigators for decades. More recently, global observations of the oxygen airglow, interpreted with the help of global circulation models have provided some understanding. Zonally averaged satellite observations clearly demonstrate the dynamical influence of tides on the daily variations. Global maps for a single day show a longitudinal variation results from planetary waves. For a single ground-station, the observations are influenced by both, involving variability over days or weeks. During the course of the year both annual and semi-annual components of the variation have been identified. In the present investigation these are studied using data from the WIND Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite, and model results from the TIME-GCM model. The annual variation can be described in terms of a rapid buildup of atomic oxygen in the fall, manifested as high airglow levels at polar latitudes in early winter that decay gradually during the winter period, and are abruptly terminated by a strong atomic oxygen depletion in spring that has been called the springtime transition. The summer values remain low until the sudden autumn rise that can be called the autumnal transition. However, the observations show significant differences between the northern and southern hemispheres. The semi-annual variation dominates at latitudes below 30 and appears to be the result of changes in the mixing intensity that may be linked to the semi-annual variation in the amplitude of the diurnal tide.

  17. Atomic oxidation of large area epitaxial graphene on 4H-SiC(0001)

    SciTech Connect

    Velez-Fort, E.; Ouerghi, A.; Silly, M. G.; Sirtti, F.; Eddrief, M.; Marangolo, M.; Shukla, A.

    2014-03-03

    Structural and electronic properties of epitaxial graphene on 4H-SiC were studied before and after an atomic oxidation process. X-ray photoemission spectroscopy indicates that oxygen penetrates into the substrate and decouples a part of the interface layer. Raman spectroscopy demonstrates the increase of defects due to the presence of oxygen. Interestingly, we observed on the near edge x-ray absorption fine structure spectra a splitting of the π* peak into two distinct resonances centered at 284.7 and 285.2 eV. This double structure smears out after the oxidation process and permits to probe the interface architecture between graphene and the substrate.

  18. An atomic magnetometer with autonomous frequency stabilization and large dynamic range.

    PubMed

    Pradhan, S; Mishra, S; Behera, R; Poornima; Dasgupta, K

    2015-06-01

    The operation of a highly sensitive atomic magnetometer using elliptically polarized resonant light is demonstrated. It is based on measurement of zero magnetic field resonance in degenerate two level systems using polarimetric detection. The transmitted light through the polarimeter is used for laser frequency stabilization, whereas reflected light is used for magnetic field measurement. Thus, the experimental geometry allows autonomous frequency stabilization of the laser frequency leading to compact operation of the overall device and has a preliminary sensitivity of <10 pT/Hz(1/2) @ 1 Hz. Additionally, the dynamic range of the device is improved by feedback controlling the bias magnetic field without compromising on its sensitivity. PMID:26133825

  19. An atomic magnetometer with autonomous frequency stabilization and large dynamic range

    SciTech Connect

    Pradhan, S. E-mail: pradhans75@gmail.com; Poornima,; Dasgupta, K.; Mishra, S.; Behera, R.

    2015-06-15

    The operation of a highly sensitive atomic magnetometer using elliptically polarized resonant light is demonstrated. It is based on measurement of zero magnetic field resonance in degenerate two level systems using polarimetric detection. The transmitted light through the polarimeter is used for laser frequency stabilization, whereas reflected light is used for magnetic field measurement. Thus, the experimental geometry allows autonomous frequency stabilization of the laser frequency leading to compact operation of the overall device and has a preliminary sensitivity of <10 pT/Hz{sup 1/2} @ 1 Hz. Additionally, the dynamic range of the device is improved by feedback controlling the bias magnetic field without compromising on its sensitivity.

  20. Atomically flat Ge buffer layers and alternating shutter growth of CaGe2 for large area germanane

    NASA Astrophysics Data System (ADS)

    Xu, Jinsong; Katoch, Jyoti; Ahmed, Adam; Pinchuk, Igor; Williams, Robert; McComb, David; Kawakami, Roland

    Germanane (GeH), which is converted from CaGe2 by soaking in HCl acid, has recently attracted interest because of its novel properties, such as large band gap (1.56eV), spin orbit coupling and predictions of high mobility (18000 cm2/Vs). Previously CaGe2 was successfully grown on Ge(111) substrates by molecular beam epitaxy (MBE) growth. But there were cracks between µm-sized islands, which is not desirable for scientific study and application, and limits the material quality. By growing atomically flat Ge buffer layers and using alternating shutter MBE growth, we are able to grow crack-free, large area films of CaGe2 films. Reflection high energy electron diffraction (RHEED) patterns of Ge buffer layer and CaGe2 indicates high quality two dimensional surfaces, which is further confirmed by atomic force microscopy (AFM), showing atomically flat and uniform Ge buffer layer and CaGe2. The appearance of Laue oscillation in X-ray diffraction (XRD) and Kiessig fringes in X-ray reflectivity (XRR) proves the uniformity of CaGe2 film and the smoothness of the interface. The high quality of CaGe2 film makes it promising to explore novel properties of GeH. Funded by NSF MRSEC DMR-1420451.

  1. The survivability of large space-borne reflectors under atomic oxygen and micrometeoroid impact

    NASA Technical Reports Server (NTRS)

    Gulino, D. A.

    1987-01-01

    Solar dynamic power system mirrors for use on space station and other spacecraft flown in low Earth orbit (LEO) are exposed to the harshness of the LEO environment. Both atomic oxygen and micrometeoroids/space debris can degrade the performance of such mirrors. Protective coatings will be required to protect oxidizable reflecting media, such as silver and aluminum, from atomic oxygen attack. Several protective coating materials have been identified as good candidates for use in this application. The durability of these coating/mirror systems after pinhole defects have been inflicted during their fabrication and deployment or through micrometeoroid/space debris impact once on-orbit is of concern. Studies of the effect of an oxygen plasma environment on protected mirror surfaces with intentionally induced pinhole defects have been conducted at NASA Lewis and are reviewed. It has been found that oxidation of the reflective layer and/or the substrate in areas adjacent to a pinhole defect, but not directly exposed by the pinhole, can occur.

  2. The survivability of large space-borne reflectors under atomic oxygen and micrometeoroid impact

    NASA Technical Reports Server (NTRS)

    Gulino, Daniel A.

    1987-01-01

    Solar dynamic power system mirrors for use on Space Station and other spacecraft flown in low earth orbit (LEO) are exposed to the harshness of the LEO environment. Both atomic oxygen and micrometeoroids/space debris can degrade the performance of such mirrors. Protective coatings will be required to protect oxidizable reflecting media, such as silver and aluminum, from atomic oxygen attack. Several protective coating materials have been identified as good candidates for use in this application. The durability of these coating/mirror systems after pinhole defects have been inflicted during their fabrication and deployment or through micrometeoroid/space debris impact once on-orbit is of concern. Studies of the effect of an oxygen plasma environment on protected mirror surfaces with intentionally induced pinhole defects have been conducted at NASA Lewis and are reviewed. It has been found that oxidation of the reflective layer and/or the substrate in areas adjacent to a pinhole defect, but not directly exposed by the pinhole, can occur.

  3. On the performance of large Gaussian basis sets for the computation of total atomization energies

    NASA Technical Reports Server (NTRS)

    Martin, J. M. L.

    1992-01-01

    The total atomization energies of a number of molecules have been computed using an augmented coupled-cluster method and (5s4p3d2f1g) and 4s3p2d1f) atomic natural orbital (ANO) basis sets, as well as the correlation consistent valence triple zeta plus polarization (cc-pVTZ) correlation consistent valence quadrupole zeta plus polarization (cc-pVQZ) basis sets. The performance of ANO and correlation consistent basis sets is comparable throughout, although the latter can result in significant CPU time savings. Whereas the inclusion of g functions has significant effects on the computed Sigma D(e) values, chemical accuracy is still not reached for molecules involving multiple bonds. A Gaussian-1 (G) type correction lowers the error, but not much beyond the accuracy of the G1 model itself. Using separate corrections for sigma bonds, pi bonds, and valence pairs brings down the mean absolute error to less than 1 kcal/mol for the spdf basis sets, and about 0.5 kcal/mol for the spdfg basis sets. Some conclusions on the success of the Gaussian-1 and Gaussian-2 models are drawn.

  4. Large numbers of cold positronium atoms created in laser-selected Rydberg states using resonant charge exchange

    NASA Astrophysics Data System (ADS)

    McConnell, R.; Gabrielse, G.; Kolthammer, W. S.; Richerme, P.; Müllers, A.; Walz, J.; Grzonka, D.; Zielinski, M.; Fitzakerley, D.; George, M. C.; Hessels, E. A.; Storry, C. H.; Weel, M.; ATRAP Collaboration

    2016-03-01

    Lasers are used to control the production of highly excited positronium atoms (Ps*). The laser light excites Cs atoms to Rydberg states that have a large cross section for resonant charge-exchange collisions with cold trapped positrons. For each trial with 30 million trapped positrons, more than 700 000 of the created Ps* have trajectories near the axis of the apparatus, and are detected using Stark ionization. This number of Ps* is 500 times higher than realized in an earlier proof-of-principle demonstration (2004 Phys. Lett. B 597 257). A second charge exchange of these near-axis Ps* with trapped antiprotons could be used to produce cold antihydrogen, and this antihydrogen production is expected to be increased by a similar factor.

  5. Particle displacement tracking for PIV

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.

    1990-01-01

    A new Particle Imaging Velocimetry (PIV) data acquisition and analysis system, which is an order of magnitude faster than any previously proposed system has been constructed and tested. The new Particle Displacement Tracing (PDT) system is an all electronic technique employing a video camera and a large memory buffer frame-grabber board. Using a simple encoding scheme, a time sequence of single exposure images are time coded into a single image and then processed to track particle displacements and determine velocity vectors. Application of the PDT technique to a counter-rotating vortex flow produced over 1100 velocity vectors in 110 seconds when processed on an 80386 PC.

  6. Rapid silica atomic layer deposition on large quantities of cohesive nanoparticles.

    PubMed

    Liang, Xinhua; Barrett, Kathryn S; Jiang, Ying-Bing; Weimer, Alan W

    2010-08-01

    Conformal silica films were deposited on anatase titania nanoparticles using rapid silica atomic layer deposition (ALD) in a fluidized bed reactor. Alternating doses of tris(tert-pentoxy)silanol (TPS) and trimethylaluminum (TMA) precursor vapors were used at 175 degrees C. In situ mass spectroscopy verified the growth mechanism through a siloxane polymerization process. Transmission electron microscopy revealed highly conformal and uniform silica nanofilms on the surface of titania nanoparticles. A growth rate of approximately 1.8 nm/cycle was achieved for an underdosed and incomplete polymerization reaction. Primary nanoparticles were coated despite their strong tendency to form dynamic agglomerates during fluidization. Methylene blue oxidation tests indicated that the photoactivity of anatase titania particles was mitigated with the ALD films. PMID:20735095

  7. Large-scale displacement along the Altyn Tagh Fault (North Tibet) since its Eocene initiation: Insight from detrital zircon U-Pb geochronology and subsurface data

    NASA Astrophysics Data System (ADS)

    Cheng, Feng; Jolivet, Marc; Fu, Suotang; Zhang, Changhao; Zhang, Qiquan; Guo, Zhaojie

    2016-05-01

    Marking the northern boundary of the Tibetan plateau, the Altyn Tagh fault plays a crucial role in accommodating the Cenozoic crustal deformation affecting the plateau. However, its initiation time and amount of offset are still controversial despite being key information for the understanding of Tibet evolution. In this study, we present 1122 single LA-ICP-MS detrital zircon U-Pb ages obtained from 11 Mesozoic to Cenozoic sandstone samples, collected along two sections in the northwestern Qaidam basin (Eboliang and Huatugou). These data are combined with new 3D seismic reflection profiles to demonstrate that: (1) from the Paleocene to early Eocene, the Eboliang section was approximately located near the present position of Anxi, 360 ± 40 km southwest from its current location along the Altyn Tagh fault, and sediments were mainly derived from the Altyn Tagh Range. At the same period, the Huatugou section was approximately located near the present position of Tula, ca. 360 km southwest from its current location along the Altyn Tagh fault, and the Eastern Kunlun Range represented a significant sediment source. (2) Left-lateral strike-slip movement along the Altyn Tagh fault initiated during the early-middle Eocene, resulting in northeastward displacement of the two sections. (3) By early Miocene, the intensive deformation within the Altyn Tagh Range and northwestern Qaidam basin strongly modified the drainage system, preventing the materials derived from the Altyn Tagh Range to reach the Eboliang and the Huatugou sections. The post-Oligocene clastic material in the western Qaidam basin is generally derived from local sources and recycling of the deformed Paleocene to Oligocene strata. From these data, we suggest enhanced tectonic activity within the Altyn Tagh Range and northwestern Qaidam basin since Miocene time, and propose an early-middle Eocene initiation of left-lateral strike-slip faulting leading to a 360 ± 40 km offset along the Altyn Tagh fault.

  8. Displacement Cascade Damage Production in Metals

    SciTech Connect

    Stoller, Roger E; Malerba, Lorenzo; Nordlund, Kai

    2015-01-01

    Radiation-induced changes in microstructure and mechanical properties in structural materials are the result of a complex set of physical processes initiated by the collision between an energetic particle (neutron or ion) and an atom in the lattice. This primary damage event is called an atomic displacement cascade. The simplest description of a displacement cascade is to view it as a series of many billiard-ball-like elastic collisions among the atoms in the material. This chapter describes the formation and evolution of this primary radiation damage mechanism to provide an overview of how stable defects are formed by displacement cascades, as well as the nature and morphology of the defects themselves. The impact of the relevant variables such as cascade energy and irradiation temperature is discussed, and defect formation in different materials is compared.

  9. Large-Scale Production of Large-Size Atomically Thin Semiconducting Molybdenum Dichalcogenide Sheets in Water and Its Application for Supercapacitor

    PubMed Central

    Chen, Yu-Xiang; Wu, Chien-Wei; Kuo, Ting-Yang; Chang, Yu-Lung; Jen, Ming-Hsing; Chen, I-Wen Peter

    2016-01-01

    To progress from laboratory research to commercial applications, it is necessary to develop an effective method to prepare large quantities and high-quality of the large-size atomically thin molybdenum dichalcogenides (MoS2). Aqueous-phase processes provide a viable method for producing thin MoS2 sheets using organolithium-assisted exfoliation; unfortunately, this method is hindered by changing pristine semiconducting 2H phase to distorted metallic 1T phase. Recovery of the intrinsic 2H phase typically involves heating of the 1T MoS2 sheets on solid substrates at high temperature. This has restricted and hindered the utilization of 2H phase MoS2 sheets suspensions. Here, we demonstrate that the synergistic effect of the rigid planar structure and charged nature of organic salt such as imidazole (ImH) can be successfully used to produce atomically thin 2H-MoS2 sheets suspension in water. Moreover, lateral size and area of the exfoliated sheet can be up to 50 μm and 1000 μm2, respectively. According to the XPS measurements, nearly 100% of the 2H-MoS2 sheets was successfully prepared. A composite paper supercapacitor using the exfoliated 2H-MoS2 and carbon nanotubes delivered a superior volumetric capacitance of ~410 F/cm3. Therefore, the organic salts-assisted liquid-phase exfoliation has great potential for large-scale production of 2H-MoS2 suspensions for supercapacitor application. PMID:27225297

  10. Large-Scale Production of Large-Size Atomically Thin Semiconducting Molybdenum Dichalcogenide Sheets in Water and Its Application for Supercapacitor

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Xiang; Wu, Chien-Wei; Kuo, Ting-Yang; Chang, Yu-Lung; Jen, Ming-Hsing; Chen, I.-Wen Peter

    2016-05-01

    To progress from laboratory research to commercial applications, it is necessary to develop an effective method to prepare large quantities and high-quality of the large-size atomically thin molybdenum dichalcogenides (MoS2). Aqueous-phase processes provide a viable method for producing thin MoS2 sheets using organolithium-assisted exfoliation; unfortunately, this method is hindered by changing pristine semiconducting 2H phase to distorted metallic 1T phase. Recovery of the intrinsic 2H phase typically involves heating of the 1T MoS2 sheets on solid substrates at high temperature. This has restricted and hindered the utilization of 2H phase MoS2 sheets suspensions. Here, we demonstrate that the synergistic effect of the rigid planar structure and charged nature of organic salt such as imidazole (ImH) can be successfully used to produce atomically thin 2H-MoS2 sheets suspension in water. Moreover, lateral size and area of the exfoliated sheet can be up to 50 μm and 1000 μm2, respectively. According to the XPS measurements, nearly 100% of the 2H-MoS2 sheets was successfully prepared. A composite paper supercapacitor using the exfoliated 2H-MoS2 and carbon nanotubes delivered a superior volumetric capacitance of ~410 F/cm3. Therefore, the organic salts-assisted liquid-phase exfoliation has great potential for large-scale production of 2H-MoS2 suspensions for supercapacitor application.

  11. Large-Scale Production of Large-Size Atomically Thin Semiconducting Molybdenum Dichalcogenide Sheets in Water and Its Application for Supercapacitor.

    PubMed

    Chen, Yu-Xiang; Wu, Chien-Wei; Kuo, Ting-Yang; Chang, Yu-Lung; Jen, Ming-Hsing; Chen, I-Wen Peter

    2016-01-01

    To progress from laboratory research to commercial applications, it is necessary to develop an effective method to prepare large quantities and high-quality of the large-size atomically thin molybdenum dichalcogenides (MoS2). Aqueous-phase processes provide a viable method for producing thin MoS2 sheets using organolithium-assisted exfoliation; unfortunately, this method is hindered by changing pristine semiconducting 2H phase to distorted metallic 1T phase. Recovery of the intrinsic 2H phase typically involves heating of the 1T MoS2 sheets on solid substrates at high temperature. This has restricted and hindered the utilization of 2H phase MoS2 sheets suspensions. Here, we demonstrate that the synergistic effect of the rigid planar structure and charged nature of organic salt such as imidazole (ImH) can be successfully used to produce atomically thin 2H-MoS2 sheets suspension in water. Moreover, lateral size and area of the exfoliated sheet can be up to 50 μm and 1000 μm(2), respectively. According to the XPS measurements, nearly 100% of the 2H-MoS2 sheets was successfully prepared. A composite paper supercapacitor using the exfoliated 2H-MoS2 and carbon nanotubes delivered a superior volumetric capacitance of ~410 F/cm(3). Therefore, the organic salts-assisted liquid-phase exfoliation has great potential for large-scale production of 2H-MoS2 suspensions for supercapacitor application. PMID:27225297

  12. Atomic Number Dependence of Hadron Production at Large Transverse Momentum in 300 GeV Proton--Nucleus Collisions

    DOE R&D Accomplishments Database

    Cronin, J. W.; Frisch, H. J.; Shochet, M. J.; Boymond, J. P.; Mermod, R.; Piroue, P. A.; Sumner, R. L.

    1974-07-15

    In an experiment at the Fermi National Accelerator Laboratory we have compared the production of large transverse momentum hadrons from targets of W, Ti, and Be bombarded by 300 GeV protons. The hadron yields were measured at 90 degrees in the proton-nucleon c.m. system with a magnetic spectrometer equipped with 2 Cerenkov counters and a hadron calorimeter. The production cross-sections have a dependence on the atomic number A that grows with P{sub 1}, eventually leveling off proportional to A{sup 1.1}.

  13. Synthesis of large and few atomic layers of hexagonal boron nitride on melted copper.

    PubMed

    Khan, Majharul Haque; Huang, Zhenguo; Xiao, Feng; Casillas, Gilberto; Chen, Zhixin; Molino, Paul J; Liu, Hua Kun

    2015-01-01

    Hexagonal boron nitride nanosheets (h-BNNS) have been proposed as an ideal substrate for graphene-based electronic devices, but the synthesis of large and homogeneous h-BNNS is still challenging. In this contribution, we report a facile synthesis of few-layer h-BNNS on melted copper via an atmospheric pressure chemical vapor deposition process. Comparative studies confirm the advantage of using melted copper over solid copper as a catalyst substrate. The former leads to the formation of single crystalline h-BNNS that is several microns in size and mostly in mono- and bi-layer forms, in contrast to the polycrystalline and mixed multiple layers (1-10) yielded by the latter. This difference is likely to be due to the significantly reduced and uniformly distributed nucleation sites on the smooth melted surface, in contrast to the large amounts of unevenly distributed nucleation sites that are associated with grain boundaries and other defects on the solid surface. This synthesis is expected to contribute to the development of large-scale manufacturing of h-BNNS/graphene-based electronics. PMID:25582557

  14. Synthesis of Large and Few Atomic Layers of Hexagonal Boron Nitride on Melted Copper

    PubMed Central

    Khan, Majharul Haque; Huang, Zhenguo; Xiao, Feng; Casillas, Gilberto; Chen, Zhixin; Molino, Paul J.; Liu, Hua Kun

    2015-01-01

    Hexagonal boron nitride nanosheets (h-BNNS) have been proposed as an ideal substrate for graphene-based electronic devices, but the synthesis of large and homogeneous h-BNNS is still challenging. In this contribution, we report a facile synthesis of few-layer h-BNNS on melted copper via an atmospheric pressure chemical vapor deposition process. Comparative studies confirm the advantage of using melted copper over solid copper as a catalyst substrate. The former leads to the formation of single crystalline h-BNNS that is several microns in size and mostly in mono- and bi-layer forms, in contrast to the polycrystalline and mixed multiple layers (1–10) yielded by the latter. This difference is likely to be due to the significantly reduced and uniformly distributed nucleation sites on the smooth melted surface, in contrast to the large amounts of unevenly distributed nucleation sites that are associated with grain boundaries and other defects on the solid surface. This synthesis is expected to contribute to the development of large-scale manufacturing of h-BNNS/graphene-based electronics. PMID:25582557

  15. Synthesis of Large and Few Atomic Layers of Hexagonal Boron Nitride on Melted Copper

    NASA Astrophysics Data System (ADS)

    Khan, Majharul Haque; Huang, Zhenguo; Xiao, Feng; Casillas, Gilberto; Chen, Zhixin; Molino, Paul J.; Liu, Hua Kun

    2015-01-01

    Hexagonal boron nitride nanosheets (h-BNNS) have been proposed as an ideal substrate for graphene-based electronic devices, but the synthesis of large and homogeneous h-BNNS is still challenging. In this contribution, we report a facile synthesis of few-layer h-BNNS on melted copper via an atmospheric pressure chemical vapor deposition process. Comparative studies confirm the advantage of using melted copper over solid copper as a catalyst substrate. The former leads to the formation of single crystalline h-BNNS that is several microns in size and mostly in mono- and bi-layer forms, in contrast to the polycrystalline and mixed multiple layers (1-10) yielded by the latter. This difference is likely to be due to the significantly reduced and uniformly distributed nucleation sites on the smooth melted surface, in contrast to the large amounts of unevenly distributed nucleation sites that are associated with grain boundaries and other defects on the solid surface. This synthesis is expected to contribute to the development of large-scale manufacturing of h-BNNS/graphene-based electronics.

  16. Elucidating Common Structural Features of Human Pathogenic Variations Using Large-Scale Atomic-Resolution Protein Networks

    PubMed Central

    Das, Jishnu; Lee, Hao Ran; Sagar, Adithya; Fragoza, Robert; Liang, Jin; Wei, Xiaomu; Wang, Xiujuan; Mort, Matthew; Stenson, Peter D.; Cooper, David N.; Yu, Haiyuan

    2016-01-01

    With the rapid growth of structural genomics, numerous protein crystal structures have become available. However, the parallel increase in knowledge of the functional principles underlying biological processes, and more specifically the underlying molecular mechanisms of disease, has been less dramatic. This notwithstanding, the study of complex cellular networks has made possible the inference of protein functions on a large scale. Here, we combine the scale of network systems biology with the resolution of traditional structural biology to generate a large-scale atomic-resolution interactome-network comprising 3,398 interactions between 2,890 proteins with a well-defined interaction interface and interface residues for each interaction. Within the framework of this atomic-resolution network, we have explored the structural principles underlying variations causing human-inherited disease. We find that in-frame pathogenic variations are enriched at both the interface and in the interacting domain, suggesting that variations not only at interface “hot-spots,” but in the entire interacting domain can result in alterations of interactions. Further, the sites of pathogenic variations are closely related to the biophysical strength of the interactions they perturb. Finally, we show that biochemical alterations consequent to these variations are considerably more disruptive than evolutionary changes, with the most significant alterations at the protein interaction interface. PMID:24599843

  17. Precision displacement reference system

    DOEpatents

    Bieg, Lothar F.; Dubois, Robert R.; Strother, Jerry D.

    2000-02-22

    A precision displacement reference system is described, which enables real time accountability over the applied displacement feedback system to precision machine tools, positioning mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.

  18. Large-dimension configuration-interaction calculations of positron binding to the group-II atoms

    SciTech Connect

    Bromley, M. W. J.; Mitroy, J.

    2006-03-15

    The configuration-interaction (CI) method is applied to the calculation of the structures of a number of positron binding systems, including e{sup +}Be, e{sup +}Mg, e{sup +}Ca, and e{sup +}Sr. These calculations were carried out in orbital spaces containing about 200 electron and 200 positron orbitals up to l=12. Despite the very large dimensions, the binding energy and annihilation rate converge slowly with l, and the final values do contain an appreciable correction obtained by extrapolating the calculation to the l{yields}{infinity} limit. The binding energies were 0.00317 hartree for e{sup +}Be, 0.0170 hartree for e{sup +}Mg, 0.0189 hartree for e{sup +}Ca, and 0.0131 hartree for e{sup +}Sr.

  19. INCAS: an analytical model to describe displacement cascades

    NASA Astrophysics Data System (ADS)

    Jumel, Stéphanie; Claude Van-Duysen, Jean

    2004-07-01

    REVE (REactor for Virtual Experiments) is an international project aimed at developing tools to simulate neutron irradiation effects in Light Water Reactor materials (Fe, Ni or Zr-based alloys). One of the important steps of the project is to characterise the displacement cascades induced by neutrons. Accordingly, the Department of Material Studies of Electricité de France developed an analytical model based on the binary collision approximation. This model, called INCAS (INtegration of CAScades), was devised to be applied on pure elements; however, it can also be used on diluted alloys (reactor pressure vessel steels, etc.) or alloys composed of atoms with close atomic numbers (stainless steels, etc.). INCAS describes displacement cascades by taking into account the nuclear collisions and electronic interactions undergone by the moving atoms. In particular, it enables to determine the mean number of sub-cascades induced by a PKA (depending on its energy) as well as the mean energy dissipated in each of them. The experimental validation of INCAS requires a large effort and could not be carried out in the framework of the study. However, it was verified that INCAS results are in conformity with those obtained from other approaches. As a first application, INCAS was applied to determine the sub-cascade spectrum induced in iron by the neutron spectrum corresponding to the central channel of the High Flux Irradiation Reactor of Oak Ridge National Laboratory.

  20. Meta-Atom Behavior in Clusters Revealing Large Spin Ground States.

    PubMed

    Hernández Sánchez, Raúl; Betley, Theodore A

    2015-11-01

    The field of single molecule magnetism remains predicated on super- and double exchange mechanisms to engender large spin ground states. An alternative approach to achieving high-spin architectures involves synthesizing weak-field clusters featuring close M-M interactions to produce a single valence orbital manifold. Population of this orbital manifold in accordance with Hund's rules could potentially yield thermally persistent high-spin ground states under which the valence electrons remain coupled. We now demonstrate this effect with a reduced hexanuclear iron cluster that achieves an S = 19/2 (χ(M)T ≈ 53 cm(3) K/mol) ground state that persists to 300 K, representing the largest spin ground state persistent to room temperature reported to date. The reduced cluster displays single molecule magnet behavior manifest in both variable-temperature zero-field (57)Fe Mössbauer and magnetometry with a spin reversal barrier of 42.5(8) cm(-1) and a magnetic blocking temperature of 2.9 K (0.059 K/min). PMID:26440452

  1. Accelerating solidification process simulation for large-sized system of liquid metal atoms using GPU with CUDA

    NASA Astrophysics Data System (ADS)

    Jie, Liang; Li, KenLi; Shi, Lin; Liu, RangSu; Mei, Jing

    2014-01-01

    Molecular dynamics simulation is a powerful tool to simulate and analyze complex physical processes and phenomena at atomic characteristic for predicting the natural time-evolution of a system of atoms. Precise simulation of physical processes has strong requirements both in the simulation size and computing timescale. Therefore, finding available computing resources is crucial to accelerate computation. However, a tremendous computational resource (GPGPU) are recently being utilized for general purpose computing due to its high performance of floating-point arithmetic operation, wide memory bandwidth and enhanced programmability. As for the most time-consuming component in MD simulation calculation during the case of studying liquid metal solidification processes, this paper presents a fine-grained spatial decomposition method to accelerate the computation of update of neighbor lists and interaction force calculation by take advantage of modern graphics processors units (GPU), enlarging the scale of the simulation system to a simulation system involving 10 000 000 atoms. In addition, a number of evaluations and tests, ranging from executions on different precision enabled-CUDA versions, over various types of GPU (NVIDIA 480GTX, 580GTX and M2050) to CPU clusters with different number of CPU cores are discussed. The experimental results demonstrate that GPU-based calculations are typically 9∼11 times faster than the corresponding sequential execution and approximately 1.5∼2 times faster than 16 CPU cores clusters implementations. On the basis of the simulated results, the comparisons between the theoretical results and the experimental ones are executed, and the good agreement between the two and more complete and larger cluster structures in the actual macroscopic materials are observed. Moreover, different nucleation and evolution mechanism of nano-clusters and nano-crystals formed in the processes of metal solidification is observed with large-sized system.

  2. Accelerating solidification process simulation for large-sized system of liquid metal atoms using GPU with CUDA

    SciTech Connect

    Jie, Liang; Li, KenLi; Shi, Lin; Liu, RangSu; Mei, Jing

    2014-01-15

    Molecular dynamics simulation is a powerful tool to simulate and analyze complex physical processes and phenomena at atomic characteristic for predicting the natural time-evolution of a system of atoms. Precise simulation of physical processes has strong requirements both in the simulation size and computing timescale. Therefore, finding available computing resources is crucial to accelerate computation. However, a tremendous computational resource (GPGPU) are recently being utilized for general purpose computing due to its high performance of floating-point arithmetic operation, wide memory bandwidth and enhanced programmability. As for the most time-consuming component in MD simulation calculation during the case of studying liquid metal solidification processes, this paper presents a fine-grained spatial decomposition method to accelerate the computation of update of neighbor lists and interaction force calculation by take advantage of modern graphics processors units (GPU), enlarging the scale of the simulation system to a simulation system involving 10 000 000 atoms. In addition, a number of evaluations and tests, ranging from executions on different precision enabled-CUDA versions, over various types of GPU (NVIDIA 480GTX, 580GTX and M2050) to CPU clusters with different number of CPU cores are discussed. The experimental results demonstrate that GPU-based calculations are typically 9∼11 times faster than the corresponding sequential execution and approximately 1.5∼2 times faster than 16 CPU cores clusters implementations. On the basis of the simulated results, the comparisons between the theoretical results and the experimental ones are executed, and the good agreement between the two and more complete and larger cluster structures in the actual macroscopic materials are observed. Moreover, different nucleation and evolution mechanism of nano-clusters and nano-crystals formed in the processes of metal solidification is observed with large

  3. Amorphization of Silicon Carbide by Carbon Displacement

    SciTech Connect

    Devanathan, Ram; Gao, Fei; Weber, William J.

    2004-05-10

    We have used molecular dynamics simulations to examine the possibility of amorphizing silicon carbide (SiC) by exclusively displacing C atoms. At a defect generation corresponding to 0.2 displacements per atom, the enthalpy surpasses the level of melt-quenched SiC, the density decreases by about 15%, and the radial distribution function shows a lack of long-range order. Prior to amorphization, the surviving defects are mainly C Frenkel pairs (67%), but Si Frenkel pairs (18%) and anti-site defects (15%) are also present. The results indicate that SiC can be amorphized by C sublattice displacements. Chemical short-range disorder, arising mainly from interstitial production, plays a significant role in the amorphization.

  4. Linking Species Traits to the Abiotic Template of Flowing Waters: Contrasting Eco physiologies Underlie Displacement of Zebra Mussels by Quagga Mussels in a Large River-Estuary

    NASA Astrophysics Data System (ADS)

    Casper, A. F.

    2005-05-01

    The St. Lawrence River-Estuary was the gateway of entry for dreissenids to North America and holds some of the oldest populations. The St. Lawrence also has four distinct physical-chemical water masses (a regional scale abiotic template) that both species inhabit. Despite their ecological similarities, quagga mussels are supplanting zebra mussels in much of their shared range. In order to try to better understand the changing distributions of these two species we compared glycogen, shell mass and tissue biomass in each of the water masses. This comparative physiological combined with experimental approaches (estuarine salinity experiments and reciprocal transplants) showed that while quagga mussels should dominate in most habitats, that abiotic/bioenergetic constraints in two regions (the Ottawa River plume and the freshwater-marine transition zone) might prevent them from dominating these locations. These findings are an example of how the interaction of landscape scale abiotic heterogeneity and a species-specific physiology can have strong impacts of distribution of biota large rivers.

  5. Design and control of multi-actuated atomic force microscope for large-range and high-speed imaging.

    PubMed

    Soltani Bozchalooi, I; Careaga Houck, A; AlGhamdi, J; Youcef-Toumi, K

    2016-01-01

    This paper presents the design and control of a high-speed and large-range atomic force microscopy (AFM). A multi-actuation scheme is proposed where several nano-positioners cooperate to achieve the range and speed requirements. A simple data-based control design methodology is presented to effectively operate the AFM scanner components. The proposed controllers compensate for the coupled dynamics and divide the positioning responsibilities between the scanner components. As a result, the multi-actuated scanner behavior is equivalent to that of a single X-Y-Z positioner with large range and high speed. The scanner of the designed AFM is composed of five nano-positioners, features 6 μm out-of-plane and 120 μm lateral ranges and is capable of high-speed operation. The presented AFM has a modular design with laser spot size of 3.5 μm suitable for small cantilever, an optical view of the sample and probe, a conveniently large waterproof sample stage and a 20 MHz data throughput for high resolution image acquisition at high imaging speeds. This AFM is used to visualize etching of calcite in a solution of sulfuric acid. Layer-by-layer dissolution and pit formation along the crystalline lines in a low pH environment is observed in real time. PMID:26547505

  6. Pulse Controlled Frequency-Chirped Laser Light at Large Detuning for Use in Atomic, Molecular, and Optical Physics Experiments

    NASA Astrophysics Data System (ADS)

    Kaufman, Brian; Paltoo, Tracy; Grogan, Tanner; Wright, Matthew

    2016-05-01

    We have developed a laser system that generates a moderate frequency chirp (1 GHz in 4 ns) at a large controllable detuning (~7 GHz) using an electro-optical phase modulator in an injection-lock laser system. This system can effectively pulse the laser on timescales less than 3 ns by turning on and off the injection lock. This system can also create arbitrary frequency chirp shapes on the laser on the tens of nanosecond time scales with a cutoff frequency of 200 MHz. As a test of the laser system, we have explored excitation of a room-temperature atomic Rb gas with frequency-chirped light. We have found that our experimental results agree with the solution to the Optical Bloch equations for the same parameters.

  7. Sensitivity function analysis of gravitational wave detection with single-laser and large-momentum-transfer atomic sensors

    NASA Astrophysics Data System (ADS)

    Tang, Biao; Zhang, Bao-Cheng; Zhou, Lin; Wang, Jin; Zhan, Ming-Sheng

    2015-03-01

    Recently, a configuration using atomic interferometers (AIs) had been suggested for the detection of gravitational waves. A new AI with some additional laser pulses for implementing large momentum transfer was also put forward, in order to reduce the effect of shot noise and laser frequency noise. We use a sensitivity function to analyze all possible configurations of the new AI and to distinguish how many momenta are transferred in a specific configuration. By analyzing the new configuration, we further explore a detection scheme for gravitational waves, in particular, that ameliorates laser frequency noise. We find that the amelioration occurs in such a scheme, but novelly, in some cases, the frequency noise can be canceled completely by using a proper data processing method. Supported by the National Natural Science Foundation of China.

  8. Large-scale B-spline R-matrix calculations of electron impact excitation and ionization processes in complex atoms

    NASA Astrophysics Data System (ADS)

    Zatsarinny, Oleg

    2013-09-01

    In recent years, the B-spline R-matrix (BSR) method has been applied to the treatment of a large number of atomic structure and electron-atom collision problems. Characteristic features of the BSR approach include the use of B-splines as a universal basis to describe the projectile electron inside the R-matrix box and the employment of term-dependent, and hence non-orthogonal, orbitals to construct the target states. The latter flexibility has proven to be of crucial importance for complex targets with several partially filled subshells. The published computer code has since been updated and extended to allow for a fully relativistic description at the level of the Dirac-Coulomb hamiltonian. Also, the systematic inclusion of a large number of pseudo-states in the close-coupling expansion has made it possible to extend the range of applicability from elastic and inelastic low-energy near-threshold phenomena to intermediate energies (up to several times the ionization threshold) and, in particular, to describe ionization processes as well. The basic ideas of the BSR approach will be reviewed, and its application will be illustrated for a variety of targets. Particular emphasis will be placed on systems of relevance for applications in gaseous electronics, such as the generation of complete datasets for electron collisions with the heavy noble gases Ne-Xe. Many of our data, which are needed for the description of transport processes in plasmas, are available through the LXCat database. This work was performed in collaboration with Klaus Bartschat. It is supported by the National Science Foundation under Grant No. PHY-1212450 and the XSEDE Allocation PHY-090031.

  9. Conflict, displacement and health in the Middle East.

    PubMed

    Mowafi, Hani

    2011-01-01

    Displacement is a hallmark of modern humanitarian emergencies. Displacement itself is a traumatic event that can result in illness or death. Survivors face challenges including lack of adequate shelter, decreased access to health services, food insecurity, loss of livelihoods, social marginalisation as well as economic and sexual exploitation. Displacement takes many forms in the Middle East and the Arab World. Historical conflicts have resulted in long-term displacement of Palestinians. Internal conflicts have driven millions of Somalis and Sudanese from their homes. Iraqis have been displaced throughout the region by invasion and civil strife. In addition, large numbers of migrants transit Middle Eastern countries or live there illegally and suffer similar conditions as forcibly displaced people. Displacement in the Middle East is an urban phenomenon. Many displaced people live hidden among host country populations in poor urban neighbourhoods - often without legal status. This represents a challenge for groups attempting to access displaced populations. Furthermore, health information systems in host countries often do not collect data on displaced people, making it difficult to gather data needed to target interventions towards these vulnerable populations. The following is a discussion of the health impacts of conflict and displacement in the Middle East. A review was conducted of published literature on migration and displacement in the region. Different cases are discussed with an emphasis on the recent, large-scale and urban displacement of Iraqis to illustrate aspects of displacement in this region. PMID:21590557

  10. Displacement cascades in metals and ordered alloys. Molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Doan, N. V.; Vascon, R.

    1998-02-01

    The aim of the present Molecular Dynamics (MD) simulations is a better understanding of the mechanisms associated with defect production and atomic mixing occurring in displacement cascades in irradiated metals and alloys. The cascades of energy up to 30 keV were investigated by parallel MD simulations in crystals with a reasonably large size of the simulation box, containing up to 2 millions of atoms. In order to separate the effect of the mass of atoms from the chemical effect on the defect production and the disordering in alloys, cascades were generated in Ni 3Al and NiAl compounds where the Al atoms were artificially given the Ni mass. A series of artificial alloys FeAl, FeSb, FeAu, FeU were also investigated. Large interstitial clusters were found to be very mobile and a glide mechanism was pointed out. A sub-cascade formation mechanism was observed from cascades of energy equal to or higher than 5 keV and related to the quasi-channeling phenomenon.

  11. Optical measuring displacement transducers

    NASA Astrophysics Data System (ADS)

    Dich, L. Z.

    1994-09-01

    Trends in the development and production of photoelectric displacement transducers are analyzed. The technical characteristics of certain transducers are briefly presented. A table of comparisons is given, based on available information sources.

  12. Internal displacement in Burma.

    PubMed

    Lanjouw, S; Mortimer, G; Bamforth, V

    2000-09-01

    The internal displacement of populations in Burma is not a new phenomenon. Displacement is caused by numerous factors. Not all of it is due to outright violence, but much is a consequence of misguided social and economic development initiatives. Efforts to consolidate the state by assimilating populations in government-controlled areas by military authorities on the one hand, while brokering cease-fires with non-state actors on the other, has uprooted civilian populations throughout the country. Very few areas in which internally displaced persons (IDPs) are found are not facing social turmoil within a climate of impunity. Humanitarian access to IDP populations remains extremely problematic. While relatively little information has been collected, assistance has been focused on targeting accessible groups. International concern within Burma has couched the problems of displacement within general development modalities, while international attention along its borders has sought to contain displacement. With the exception of several recent initiatives, few approaches have gone beyond assistance and engaged in the prevention or protection of the displaced. PMID:11026156

  13. Job Displacement and Labor Market Mobility. Final Report.

    ERIC Educational Resources Information Center

    Podgursky, Michael; Swaim, Paul

    A study examined the labor market mobility of displaced workers, using a new data file that matches the January 1984, 1986, and 1988 Displaced Worker Surveys (DWS) to the March Current Population Surveys in the same years. This large database provides information on displaced workers and their families and permits comparison of the geographic…

  14. Implications of Research on Displaced Workers. ERIC Digest No. 80.

    ERIC Educational Resources Information Center

    Naylor, Michele

    Worker displacement is more closely related to structural features associated with firms than to the characteristics of the individuals who lost their jobs. Despite economic growth, large numbers of displaced workers continue to experience difficulty in making labor market adjustments. Programs to retrain and reemploy displaced workers exist at…

  15. Synthesis and characterization of large-area and continuous MoS2 atomic layers by RF magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Hussain, Sajjad; Shehzad, Muhammad Arslan; Vikraman, Dhanasekaran; Khan, Muhammad Farooq; Singh, Jai; Choi, Dong-Chul; Seo, Yongho; Eom, Jonghwa; Lee, Wan-Gyu; Jung, Jongwan

    2016-02-01

    In this article, we report layer-controlled, continuous and large-area molydenum sulfide (MoS2) growth onto a SiO2/Si substrate by RF sputtering combined with sulfurization. A two-step process was employed to synthesize MoS2 films. In the first step, an atomically thin MoO3 film was deposited by RF magnetron sputtering at 300 °C. Subsequently, the as-sputtered MoO3 film was further subjected to post-annealing and sulfurization processes at 650 °C for 1 hour. It was observed that the number of layers of MoS2 can be controlled by adjusting the sputtering time. The fabricated MoS2 transistors exhibited high mobility values of ~21 cm2 V-1 s-1 (bilayer) and ~25 cm2 V-1 s-1 (trilayer), on/off ratios in the range of ~107 (bilayer) and 104-105 (trilayer), respectively. We believe that our proposed paradigm can start a new method for the growth of MoS2 in future electronics and optoelectronics applications.In this article, we report layer-controlled, continuous and large-area molydenum sulfide (MoS2) growth onto a SiO2/Si substrate by RF sputtering combined with sulfurization. A two-step process was employed to synthesize MoS2 films. In the first step, an atomically thin MoO3 film was deposited by RF magnetron sputtering at 300 °C. Subsequently, the as-sputtered MoO3 film was further subjected to post-annealing and sulfurization processes at 650 °C for 1 hour. It was observed that the number of layers of MoS2 can be controlled by adjusting the sputtering time. The fabricated MoS2 transistors exhibited high mobility values of ~21 cm2 V-1 s-1 (bilayer) and ~25 cm2 V-1 s-1 (trilayer), on/off ratios in the range of ~107 (bilayer) and 104-105 (trilayer), respectively. We believe that our proposed paradigm can start a new method for the growth of MoS2 in future electronics and optoelectronics applications. Electronic supplementary information (ESI) available: HRTEM images, XPS spectra and electrical properties. More Raman measurement spectra are obtained for MoS2 films

  16. Displaced vertices in extended supersymmetric models

    NASA Astrophysics Data System (ADS)

    Hesselbach, S.; Franke, F.; Fraas, H.

    2000-10-01

    In extended supersymmetric models with additional singlet Higgs fields displaced vertices could be observed if the decay width of the next-to-lightest supersymmetric particle becomes very small due to a singlino dominated LSP. We study the supersymmetric parameter space where displaced vertices of the second lightest neutralino exist in the NMSSM and an E6 inspired model. For a mass difference between LSP and NLSP of more than 10 GeV the singlet vacuum expectation value has to be at least of the order of /100 TeV in order to obtain a lightest neutralino with a singlino component large enough for displaced vertices.

  17. Atomistic Simulation of Displacement Cascades in Zircon

    SciTech Connect

    Devanathan, Ram; Weber, William J.; Corrales, Louis R.; BP McGrail and GA Cragnolino

    2002-05-06

    Low energy displacement cascades in zircon (ZrSiO4) initiated by a Zr primary knock-on atom have been investigated by molecular dynamics simulations using a Coulombic model for long-range interactions, Buckingham potential for short-range interactions and Ziegler-Biersack potentials for close pair interactions. Displacements were found to occur mainly in the O sublattice, and O replacements by a ring mechanism were predominant. Clusters containing Si interstitials bridged by O interstitials, vacancy clusters and anti-site defects were found to occur. This Si-O-Si bridging is considerable in quenched liquid ZrSiO4.

  18. Synthesis and characterization of large-area and continuous MoS2 atomic layers by RF magnetron sputtering.

    PubMed

    Hussain, Sajjad; Shehzad, Muhammad Arslan; Vikraman, Dhanasekaran; Khan, Muhammad Farooq; Singh, Jai; Choi, Dong-Chul; Seo, Yongho; Eom, Jonghwa; Lee, Wan-Gyu; Jung, Jongwan

    2016-02-21

    In this article, we report layer-controlled, continuous and large-area molydenum sulfide (MoS2) growth onto a SiO2/Si substrate by RF sputtering combined with sulfurization. A two-step process was employed to synthesize MoS2 films. In the first step, an atomically thin MoO3 film was deposited by RF magnetron sputtering at 300 °C. Subsequently, the as-sputtered MoO3 film was further subjected to post-annealing and sulfurization processes at 650 °C for 1 hour. It was observed that the number of layers of MoS2 can be controlled by adjusting the sputtering time. The fabricated MoS2 transistors exhibited high mobility values of ∼21 cm(2) V(-1) s(-1) (bilayer) and ∼25 cm(2) V(-1) s(-1) (trilayer), on/off ratios in the range of ∼10(7) (bilayer) and 10(4)-10(5) (trilayer), respectively. We believe that our proposed paradigm can start a new method for the growth of MoS2 in future electronics and optoelectronics applications. PMID:26838294

  19. Water displacement mercury pump

    DOEpatents

    Nielsen, M.G.

    1984-04-20

    A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

  20. Optical displacement sensor

    DOEpatents

    Carr, Dustin W.

    2008-04-08

    An optical displacement sensor is disclosed which uses a vertical-cavity surface-emitting laser (VCSEL) coupled to an optical cavity formed by a moveable membrane and an output mirror of the VCSEL. This arrangement renders the lasing characteristics of the VCSEL sensitive to any movement of the membrane produced by sound, vibrations, pressure changes, acceleration, etc. Some embodiments of the optical displacement sensor can further include a light-reflective diffractive lens located on the membrane or adjacent to the VCSEL to control the amount of lasing light coupled back into the VCSEL. A photodetector detects a portion of the lasing light from the VCSEL to provide an electrical output signal for the optical displacement sensor which varies with the movement of the membrane.

  1. Water displacement mercury pump

    DOEpatents

    Nielsen, Marshall G.

    1985-01-01

    A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

  2. Polymerase chain displacement reaction.

    PubMed

    Harris, Claire L; Sanchez-Vargas, Irma J; Olson, Ken E; Alphey, Luke; Fu, Guoliang

    2013-02-01

    Quantitative PCR assays are now the standard method for viral diagnostics. These assays must be specific, as well as sensitive, to detect the potentially low starting copy number of viral genomic material. We describe a new technique, polymerase chain displacement reaction (PCDR), which uses multiple nested primers in a rapid, capped, one-tube reaction that increases the sensitivity of normal quantitative PCR (qPCR) assays. Sensitivity was increased by approximately 10-fold in a proof-of-principle test on dengue virus sequence. In PCDR, when extension occurs from the outer primer, it displaces the extension strand produced from the inner primer by utilizing a polymerase that has strand displacement activity. This allows a greater than 2-fold increase of amplification product for each amplification cycle and therefore increased sensitivity and speed over conventional PCR. Increased sensitivity in PCDR would be useful in nucleic acid detection for viral diagnostics. PMID:23384180

  3. Molecular-dynamics simulation of threshold displacement energies in BaTiO3

    NASA Astrophysics Data System (ADS)

    Gonzalez, E.; Abreu, Y.; Cruz, C. M.; Piñera, I.; Leyva, A.

    2015-09-01

    Molecular-dynamics simulations were used to calculate threshold displacement energies for each atom type in BaTiO3 perovskite. A primary knock-on atom with an energy range between 10 and 300 eV in principal crystallographic directions at 300 K was introduced. A statistical approach has been applied calculating displacement probability curves along main crystallographic directions. For each sublattice, the simulation was repeated from different initial conditions to estimate the uncertainty in the threshold displacement energy calculated values. The threshold displacement energies vary considerably with crystallographic direction and sublattice. The weighted average threshold displacement energies are 40 eV for oxygen, 64 eV for barium and 97 eV for titanium atoms. These values are comparable to ab initio calculated and experimentally derived values in perovskites. These results are proposed as threshold displacement energies, ideal for simulation programs that use atomic displacement calculation algorithms.

  4. Efficient methods for including quantum effects in Monte Carlo calculations of large systems: Extension of the displaced points path integral method and other effective potential methods to calculate properties and distributions

    NASA Astrophysics Data System (ADS)

    Mielke, Steven L.; Dinpajooh, Mohammadhasan; Siepmann, J. Ilja; Truhlar, Donald G.

    2013-01-01

    We present a procedure to calculate ensemble averages, thermodynamic derivatives, and coordinate distributions by effective classical potential methods. In particular, we consider the displaced-points path integral (DPPI) method, which yields exact quantal partition functions and ensemble averages for a harmonic potential and approximate quantal ones for general potentials, and we discuss the implementation of the new procedure in two Monte Carlo simulation codes, one that uses uncorrelated samples to calculate absolute free energies, and another that employs Metropolis sampling to calculate relative free energies. The results of the new DPPI method are compared to those from accurate path integral calculations as well as to results of two other effective classical potential schemes for the case of an isolated water molecule. In addition to the partition function, we consider the heat capacity and expectation values of the energy, the potential energy, the bond angle, and the OH distance. We also consider coordinate distributions. The DPPI scheme performs best among the three effective potential schemes considered and achieves very good accuracy for all of the properties considered. A key advantage of the effective potential schemes is that they display much lower statistical sampling variances than those for accurate path integral calculations. The method presented here shows great promise for including quantum effects in calculations on large systems.

  5. Displaced Children: The Psychological Implications.

    PubMed

    Joshi, Paramjit T; Fayyad, John A

    2015-10-01

    Millions of people across the world have been displaced or live in exile and/or as refugees largely as a consequence of wars, acts of terrorism, and catastrophic natural disasters. There are serious psychological consequences as a result of these extremely difficult life circumstances. Adults often can express their needs and have them be heard, whereas children are unable to do so. The children may be provided food, shelter, and clothing and have their medical needs attended to, but their emotional and psychological needs go unrecognized and unmet, with dire and monumental long-term consequences. PMID:26346385

  6. HELIUM EFFECTS ON DISPLACEMENT CASCADE IN TUNGSTEN

    SciTech Connect

    Setyawan, Wahyu; Nandipati, Giridhar; Roche, Kenneth J.; Heinisch, Howard L.; Kurtz, Richard J.; Wirth, Brian D.

    2013-09-30

    Molecular dynamics (MD) simulations were performed to investigate He effects on displacement cascades in W. Helium content, proportion of interstitial and substitutional He and temperature were varied to reveal the various effects. The effect of interstitial He on the number of self-interstitial atoms (SIAs) produced during cascade damage appears to be insignificant. However, interstitial He tends to fill a vacancy (V). Nevertheless, this process is less favorable than SIA-V recombination particularly when excess SIAs are present before a cascade. The efficiency of He filling and SIA-V recombination increases as temperature increases due to increased point defect mobility. Likewise, substitutional He is more susceptible to displacement during a collision cascade than W. This susceptibility increases towards higher temperatures. Consequently, the number of surviving V is governed by the interplay between displaced substitutional He and SIA-V recombination. The temperature dependence of these processes results in a minimum number of V reached at an intermediate temperature.

  7. Displacement of large-scale open solar magnetic fields from the zone of active longitudes and the heliospheric storm of November 3-10, 2004: 2. "Explosion" of singularity and dynamics of sunspot formation and energy release

    NASA Astrophysics Data System (ADS)

    Ivanov, K. G.

    2010-12-01

    A more detailed scenario of one stage (August-November 2004) of the quasibiennial MHD process "Origination ... and dissipation of the four-sector structure of the solar magnetic field" during the decline phase of cycle 23 has been constructed. It has been indicated that the following working hypothesis on the propagation of an MHD disturbance westward (in the direction of solar rotation) and eastward (toward the zone of active longitudes) with the displacement of the large-scale open solar magnetic field (LOSMF) from this zone can be constructed based on LOSMF model representations and data on sunspot formation, flares, active filaments, and coronal ejections as well as on the estimated contribution of sporadic energy release to the flare luminosity and kinetic energy of ejections: (1) The "explosion" of the LOSMF singularity and the formation in the explosion zone of an anemone active region (AR), which produced the satellite sunspot formation that continued west and east of the "anemone," represented a powerful and energy-intensive source of MHD processes at this stage. (2) This resulted in the origination of two "governing" large-scale MHD processes, which regulated various usual manifestations of solar activity: the fast LOSMF along the neutral line in the solar atmosphere, strongly affecting the zone of active longitudes, and the slow LOSMF in the outer layers of the convection zone. The fronts of these processes were identified by powerful (about 1031 erg) coronal ejections. (3) The collision of a wave reflected from the zone of active longitudes with the eastern front of the hydromagnetic impulse of the convection zone resulted in an increase in LOSMF magnetic fluxes, origination of an active sector boundary in the zone of active longitudes, shear-convergent motions, and generation and destabilization of the flare-productive AR 10696 responsible for the heliospheric storm of November 3-10, 2004.

  8. Evidencing `Tight Bound States' in the Hydrogen Atom:. Empirical Manipulation of Large-Scale XD in Violation of QED

    NASA Astrophysics Data System (ADS)

    Amoroso, Richard L.; Vigier, Jean-Pierre

    2013-09-01

    In this work we extend Vigier's recent theory of `tight bound state' (TBS) physics and propose empirical protocols to test not only for their putative existence, but also that their existence if demonstrated provides the 1st empirical evidence of string theory because it occurs in the context of large-scale extra dimensionality (LSXD) cast in a unique M-Theoretic vacuum corresponding to the new Holographic Anthropic Multiverse (HAM) cosmological paradigm. Physicists generally consider spacetime as a stochastic foam containing a zero-point field (ZPF) from which virtual particles restricted by the quantum uncertainty principle (to the Planck time) wink in and out of existence. According to the extended de Broglie-Bohm-Vigier causal stochastic interpretation of quantum theory spacetime and the matter embedded within it is created annihilated and recreated as a virtual locus of reality with a continuous quantum evolution (de Broglie matter waves) governed by a pilot wave - a `super quantum potential' extended in HAM cosmology to be synonymous with the a `force of coherence' inherent in the Unified Field, UF. We consider this backcloth to be a covariant polarized vacuum of the (generally ignored by contemporary physicists) Dirac type. We discuss open questions of the physics of point particles (fermionic nilpotent singularities). We propose a new set of experiments to test for TBS in a Dirac covariant polarized vacuum LSXD hyperspace suggestive of a recently tested special case of the Lorentz Transformation put forth by Kowalski and Vigier. These protocols reach far beyond the recent battery of atomic spectral violations of QED performed through NIST.

  9. Stability of Helium Clusters during Displacement Cascades

    SciTech Connect

    Yang, Li; Zu, Xiaotao T.; Xiao, H. Y.; Gao, Fei; Heinisch, Howard L.; Kurtz, Richard J.; Wang, Zhiguo; Liu, K. Z.

    2007-02-01

    The interaction of displacement cascades with helium-vacancy clusters is investigated using molecular dynamics simulations. The He-vacancy clusters initially consist of 20 vacancies with a Helium-to-vacancy ratio ranging from 0.2 to 3. The primary knock-on atom (PKA) energy, Ep, varies from 2 keV to 10 keV, and the PKA direction is chosen such that a displacement cascade is able to directly interact with a helium-vacancy cluster. The simulation results show that the effect of displacement cascades on a helium-vacancy cluster strongly depends on both the helium-to-vacancy ratio and the PKA energy. For the same PKA energy, the size of helium-vacancy clusters increases with the He/V ratio, but for the same ratio, the cluster size changes more significantly with increasing PKA energy. It has been observed that the He-vacancy clusters can be dissolved when the He/V ratio less than 1, but they are able to re-nucleate during the thermal spike phase, forming small He-V nuclei. When the He/V ratio is larger than 1, the He-V clusters can absorb a number of vacancies produced by displacement cascades, forming larger He-V clusters. These results are discussed in terms of PKA energy, helium-to-vacancy ratio, number of vacancies produced by cascades, and mobility of helium atoms.

  10. Cavity quantum optomechanics of ultracold atoms in an optical lattice: Normal-mode splitting

    SciTech Connect

    Bhattacherjee, Aranya B.

    2009-10-15

    We consider the dynamics of a movable mirror (cantilever) of a cavity coupled through radiation pressure to the light scattered from ultracold atoms in an optical lattice. Scattering from different atomic quantum states creates different quantum states of the scattered light, which can be distinguished by measurements of the displacement spectrum of the cantilever. We show that for large pump intensities the steady-state displacement of the cantilever shows bistable behavior. Due to atomic back action, the displacement spectrum of the cantilever is modified and depends on the position of the condensate in the Brillouin zone. We further analyze the occurrence of splitting of the normal mode into three modes due to mixing of the mechanical motion with the fluctuations of the cavity field and the fluctuations of the condensate with finite atomic two-body interaction.

  11. The calculation of elastic constants from displacement fluctuations

    NASA Astrophysics Data System (ADS)

    Meyers, M. T.; Rickman, J. M.; Delph, T. J.

    2005-09-01

    We present a methodology for the accurate and efficient extraction of elastic constants in homogeneous solids via the calculation of the atomic displacement correlation function. This approach is validated for cubic solids parametrized by both Lennard-Jones and embedded-atom method potentials. Finally, we also discuss the extension of this method to obtain the elastic properties of inhomogeneous solids.

  12. The photoelectric displacement converter

    NASA Astrophysics Data System (ADS)

    Dragoner, Valeriu V.

    2005-02-01

    In the article are examined questions of constructing photoelectric displacement converter satisfying demands that are stated above. Converter has channels of approximate and precise readings. The approximate reading may be accomplished either by the method of reading from a code mask or by the method of the consecutive calculation of optical scale gaps number. Phase interpolator of mouar strips" gaps is determined as a precise measuring. It is shown mathematical model of converter that allow evaluating errors and operating speed of conversion.

  13. Tunable beam displacer

    SciTech Connect

    Salazar-Serrano, Luis José; Valencia, Alejandra; Torres, Juan P.

    2015-03-15

    We report the implementation of a tunable beam displacer, composed of a polarizing beam splitter (PBS) and two mirrors, that divides an initially polarized beam into two parallel beams whose separation can be continuously tuned. The two output beams are linearly polarized with either vertical or horizontal polarization and no optical path difference is introduced between them. The wavelength dependence of the device as well as the maximum separation between the beams achievable is limited mainly by the PBS characteristics.

  14. Alginate as a displacer for protein displacement chromatography.

    PubMed

    Chen, G; Scouten, W H

    1996-01-01

    Alginate use in displacement chromatography as a displacer has been studied. The experiments showed that untreated alginate is the basis of potential displacer for displacement chromatography, but needs to be cleaved into smaller chains. Alginate treated with ultrasound, which cleaves alginate into shorter polysaccharide chains, gave better displacement than untreated alginate, while alginate subjected to limited acid hydrolysis gave the best results in displacement chromatography. It was found that the mixture of ovalbumin and beta-lactoglobulin separated well, and several components of ovalbumin were also separated and purified when alginate hydrolysate was used as a displacer. beta-Lactoglobulins A and B, which have the same molecular weight and differ in isoelectric point by only 0.1 pH units, were displaced from Q-Sepharose by alginate hydrolysate. PMID:9174919

  15. A comprehensive Two-Fluid Model for Cavitation and Primary Atomization Modelling of liquid jets - Application to a large marine Diesel injector

    NASA Astrophysics Data System (ADS)

    Habchi, Chawki; Bohbot, Julien; Schmid, Andreas; Herrmann, Kai

    2015-12-01

    In this paper, a comprehensive two-fluid model is suggested in order to compute the in-nozzle cavitating flow and the primary atomization of liquid jets, simultaneously. This model has been applied to the computation of a typical large marine Diesel injector. The numerical results have shown a strong correlation between the in-nozzle cavitating flow and the ensuing spray orientation and atomization. Indeed, the results have confirmed the existence of an off-axis liquid core. This asymmetry is likely to be at the origin of the spray deviation observed experimentally. In addition, the primary atomization begins very close to the orifice exit as in the experiments, and the smallest droplets are generated due to cavitation pocket shape oscillations located at the same side, inside the orifice.

  16. Visualization of a Large Set of Hydrogen Atomic Orbital Contours Using New and Expanded Sets of Parametric Equations

    ERIC Educational Resources Information Center

    Rhile, Ian J.

    2014-01-01

    Atomic orbitals are a theme throughout the undergraduate chemistry curriculum, and visualizing them has been a theme in this journal. Contour plots as isosurfaces or contour lines in a plane are the most familiar representations of the hydrogen wave functions. In these representations, a surface of a fixed value of the wave function ? is plotted…

  17. Bonding study of TiC and TiN. I. High-precision x-ray-diffraction determination of the valence-electron density distribution, Debye-Waller temperature factors, and atomic static displacements in TiC0.94 and TiN0.99

    NASA Astrophysics Data System (ADS)

    Dunand, A.; Flack, H. D.; Yvon, K.

    1985-02-01

    Single-crystal, high-precision, high-resolution x-ray-diffraction measurements of the substoichiometric refractory compounds TiC and TiN have been performed with AgKα radiation. Severe anisotropic general extinction affects the intense low-order reflections. Inhomogeneity in the mosaic spread and domain size produces small but significant differences between reflection and antireflection for the same plane of diffraction. These effects have been modeled and refined together with a scale factor, isotropic thermal parameters, a population parameter of the nonmetal site, the amplitude of metal-atom static displacements around nonmetal vacancies, and an atomic model which includes occupancy factors of the separate orbital contributions of the valence electrons combined with κ expansion-contraction parameters. At convergence, the ``agreement indices'' (or ``reliability factors'') were R=0.0025 for TiC0.94 and R=0.0023 for TiN0.99. The refined population parameters indicate a chemical composition of TiC0.939(9) and TiN0.99(2). The mean-square amplitudes of thermal vibrations, Ti=0.002 38(2) AṦ, C=0.003 35(8) AṦ, Ti=0.002 94(1) AṦ, and N=0.003 08(12) AṦ are consistent with the respective atomic masses. 36% of the metal atoms in TiC0.94 are involved in a relaxation around the nonmetal vacancies, being displaced from their sublattice sites by 0.097(2) Å along [100]. No evidence for static displacements was found in TiN0.99. The valence-electron density distribution can be described satisfactorily in terms of deformed atoms. No buildup of charge density occurs between atomic sites. Our analysis, similar to a Mulliken partitioning, shows first that ionicity is important, with a charge transfer from the metal to the nonmetal of [2.1(4)]e in the carbide and [1.9(4)]e in the nitride, and secondly that the charge asphericity around the metal atoms is larger in the former than in the latter, while no departure from spherical symmetry is

  18. An electromechanical displacement transducer

    NASA Astrophysics Data System (ADS)

    Villiers, Marius; Mahboob, Imran; Nishiguchi, Katsuhiko; Hatanaka, Daiki; Fujiwara, Akira; Yamaguchi, Hiroshi

    2016-08-01

    Two modes of an electromechanical resonator are coupled through the strain inside the structure with a cooperativity as high as 107, a state-of-the-art value for purely mechanical systems, which enables the observation of normal-mode splitting. This coupling is exploited to transduce the resonator’s fundamental mode into the bandwidth of the second flexural mode, which is 1.4 MHz higher in frequency. Thus, an all-mechanical heterodyne detection scheme is implemented that can be developed into a high-precision displacement sensor.

  19. Threshold displacement energy in GaN; Ab initio molecular dynamics study

    SciTech Connect

    Xiao, H. Y.; Gao, Fei; Zu, Xiaotao T.; Weber, William J.

    2009-06-25

    Large-scale ab initio molecular dynamics method has been used to determine the threshold displacement energies, Ed, along five specific directions and to determine the defect configurations created during low energy events. The Ed shows a significant dependence on direction. The minimum Ed is determined to be 39 eV along the <-1010> direction for a gallium atom and 17.0 eV along the <-1010> direction for a nitrogen atom, which are in reasonable agreement with the experimental measurements. The average Ed values determined are 73.2 and 32.4 eV for gallium and nitrogen atoms, respectively. The N defects created at low energy events along different crystallographic directions have a similar configuration (a N-N dumbbell configuration), but various configurations for Ga defects are formed in GaN.

  20. Synthesis of finite displacements and displacements in continental margins

    NASA Technical Reports Server (NTRS)

    Speed, R. C.; Elison, M. W.; Heck, F. R.; Russo, R. M.

    1988-01-01

    The scope of the project is the analysis of displacement-rate fields in the transitional regions between cratonal and oceanic lithospheres over Phanerozoic time (last 700 ma). Associated goals are an improved understanding of range of widths of major displacement zones; the partition of displacement gradients and rotations with position and depth in such zones; the temporal characteristics of such zones-the steadiness, episodicity, and duration of uniform versus nonunifrom fields; and the mechanisms and controls of the establishment and kinematics of displacement zones. The objective is to provide a context of time-averaged kinematics of displacement zones. The initial phase is divided topically among the methodology of measurement and reduction of displacements in the lithosphere and the preliminary analysis from geologic and other data of actual displacement histories from the Cordillera, Appalachians, and southern North America.

  1. Detection of a large fraction of atomic gas not associated with star-forming material in M17 SW⋆

    NASA Astrophysics Data System (ADS)

    Pérez-Beaupuits, J. P.; Stutzki, J.; Ossenkopf, V.; Spaans, M.; Güsten, R.; Wiesemeyer, H.

    2015-03-01

    Context. The [C II] 158 μm line is one of the dominant coolants of the ISM, and an important probe with which to study the star formation process. Recent Herschel/HIFI and SOFIA/GREAT observations showed that assuming the total velocity-integrated intensity of this line is directly associated with the star-forming material is inadequate. Aims: We probe the column densities and masses traced by the ionized and neutral atomic carbon with spectrally resolved maps, and compare them to the diffuse and dense molecular gas traced by [C I] and low-J CO lines toward the star-forming region M17 SW. Methods: We mapped a 4.1 pc × 4.7 pc region in the [C I] 609 μm line using the APEX telescope, as well as the CO isotopologues with the IRAM 30 m telescope. Because of the velocity-resolved spectra, we analyze the data based on velocity channel maps that are 1 km s-1 wide. We correlate their spatial distribution with that of the [C II] map obtained with SOFIA/GREAT. Optically thin approximations were used to estimate the column densities of [C I] and [C II] in each velocity channel. Results: The distribution of the emission from the isotopologues 13CO, C17O, and C18O resembles more closely that of the [C I] emission than that of the 12CO emission. The spatial distribution of the [C I] and all CO isotopologues emission was found to be associated with that of [C II] in about 20%-80% of the mapped region, with the high correlation found in the central (15-23 km s-1) velocity channels. Conclusions: The excitation temperature of [C I] ranges between 40 K and 100 K in the inner molecular region of M17 SW. Excitation temperatures up to 200 K are found along the ridge. Column densities in 1 km s-1 channels between ~1015 cm-2 and ~1017 cm-2 were found for [C I]. Just ~20 % of the velocity range (~40 km s-1) that the [C II] line spans is associated with the star-forming material traced by [C I] and CO. The total (integrated over the 0-40 km s-1 velocity range) gas mass estimated from the

  2. Polyimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor)

    1991-01-01

    Polyimidazoles (Pl) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl)imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethylacetamide, sulfolane, N-methylpyrroldinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperature under nitrogen. The di(hydroxyphenyl)imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl)imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxyphenyl)imidazole monomer. This synthetic route has provided high molecular weight Pl of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

  3. Polyimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor)

    1992-01-01

    Polyimidazoles (PI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl) imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethyl acetamide, sulfolane, N-methylpyrrolidinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl) imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl) imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxphenyl) imidazole monomer. This synthetic route has provided high molecular weight PI of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

  4. Hybrid functionals for large periodic systems in an all-electron, numeric atom-centered basis framework

    NASA Astrophysics Data System (ADS)

    Levchenko, Sergey V.; Ren, Xinguo; Wieferink, Jürgen; Johanni, Rainer; Rinke, Patrick; Blum, Volker; Scheffler, Matthias

    2015-07-01

    We describe a framework to evaluate the Hartree-Fock exchange operator for periodic electronic-structure calculations based on general, localized atom-centered basis functions. The functionality is demonstrated by hybrid-functional calculations of properties for several semiconductors. In our implementation of the Fock operator, the Coulomb potential is treated either in reciprocal space or in real space, where the sparsity of the density matrix can be exploited for computational efficiency. Computational aspects, such as the rigorous avoidance of on-the-fly disk storage, and a load-balanced parallel implementation, are also discussed. We demonstrate linear scaling of our implementation with system size by calculating the electronic structure of a bulk semiconductor (GaAs) with up to 1,024 atoms per unit cell without compromising the accuracy.

  5. Are large concentration of atomic H storable in tritium-impregnated solid in H2 below 0.10 K

    NASA Technical Reports Server (NTRS)

    Rosen, G.; Webeler, R. W. H.

    1979-01-01

    The storage and release of atomic hydrogen produced by the beta decay of tritium contained in a crystalline solid H2 matrix at concentrations greater than 2% and temperatures below 0.80 K are investigated. The temperature of a sample chamber containing tritium-impregnated H2 and placed in the mixing chamber of a dilution refrigerator was measured as the chamber was heated and cooled in order to determine the rates of energy storage and release. It is found that for samples containing 1.2 wt.% tritium, after storage at 0.054 K for 40 h, an increase in sample temperature to a trigger point of 0.17 K leads to an energy release due to the destabilization of atomic H in H2 as predicted by the phenomenological rate process theory. For a tritium weight fraction of 2.5%, energy releases were triggered at 0.54 and 0.82 K after storage at 0.080 K, indicating the trapping of H atoms at the sites of T2 and HT molecules in the sample. The application of a 15 kG magnetic field is shown to increase the storage capacity of T2 traps while reducing that of HT traps, and to lower the trigger temperatures of both. Results suggest that the direct conversion of nuclear energy to chemical energy may become technically feasible in the future.

  6. Adapting to variable prismatic displacement

    NASA Technical Reports Server (NTRS)

    Welch, Robert B.; Cohen, Malcolm M.

    1989-01-01

    In each of two studies, subjects were exposed to a continuously changing prismatic displacement with a mean value of 19 prism diopters (variable displacement) and to a fixed 19-diopter displacement (fixed displacement). In Experiment 1, significant adaptation (post-pre shifts in hand-eye coordination) was found for fixed, but not for variable, displacement. Experiment 2 demonstrated that adaptation was obtained for variable displacement, but it was very fragile and is lost if the measures of adaptation are preceded by even a very brief exposure of the hand to normal or near-normal vision. Contrary to the results of some previous studies, an increase in within-S dispersion was not found of target pointing responses as a result of exposure to variable displacement.

  7. Helium vs. Proton Induced Displacement Damage in Electronic Materials

    NASA Technical Reports Server (NTRS)

    Ringo, Sawnese; Barghouty, A. F.

    2010-01-01

    In this project, the specific effects of displacement damage due to the passage of protons and helium nuclei on some typical electronic materials will be evaluated and contrasted. As the electronic material absorbs the energetic proton and helium momentum, degradation of performance occurs, eventually leading to overall failure. Helium nuclei traveling at the same speed as protons are expected to impart more to the material displacement damage; due to the larger mass, and thus momentum, of helium nuclei compared to protons. Damage due to displacement of atoms in their crystalline structure can change the physical properties and hence performance of the electronic materials.

  8. Global surface displacement data for assessing variability of displacement at a point on a fault

    USGS Publications Warehouse

    Hecker, Suzanne; Sickler, Robert; Feigelson, Leah; Abrahamson, Norman; Hassett, Will; Rosa, Carla; Sanquini, Ann

    2014-01-01

    This report presents a global dataset of site-specific surface-displacement data on faults. We have compiled estimates of successive displacements attributed to individual earthquakes, mainly paleoearthquakes, at sites where two or more events have been documented, as a basis for analyzing inter-event variability in surface displacement on continental faults. An earlier version of this composite dataset was used in a recent study relating the variability of surface displacement at a point to the magnitude-frequency distribution of earthquakes on faults, and to hazard from fault rupture (Hecker and others, 2013). The purpose of this follow-on report is to provide potential data users with an updated comprehensive dataset, largely complete through 2010 for studies in English-language publications, as well as in some unpublished reports and abstract volumes.

  9. Strategies for displacing oil

    NASA Astrophysics Data System (ADS)

    Rao, Vikram; Gupta, Raghubir

    2015-03-01

    Oil currently holds a monopoly on transportation fuels. Until recently biofuels were seen as the means to break this stranglehold. They will still have a part to play, but the lead role has been handed to natural gas, almost solely due to the increased availability of shale gas. The spread between oil and gas prices, unprecedented in its scale and duration, will cause a secular shift away from oil as a raw material. In the transport fuel sector, natural gas will gain traction first in the displacement of diesel fuel. Substantial innovation is occurring in the methods of producing liquid fuel from shale gas at the well site, in particular in the development of small scale distributed processes. In some cases, the financing of such small-scale plants may require new business models.

  10. Variable displacement blower

    DOEpatents

    Bookout, Charles C.; Stotts, Robert E.; Waring, Douglass R.; Folsom, Lawrence R.

    1986-01-01

    A blower having a stationary casing for rotatably supporting a rotor assembly having a series of open ended chambers arranged to close against the surrounding walls of the casing. Pistons are slidably mounted within each chamber with the center of rotation of the pistons being offset in regard to the center of rotation of the rotor assembly whereby the pistons reciprocate in the chambers as the rotor assembly turns. As inlet port communicates with the rotor assembly to deliver a working substance into the chamber as the pistons approach a top dead center position in the chamber while an outlet port also communicates with the rotor to exhaust the working substance as the pistons approach a bottom dead center position. The displacement of the blower is varied by adjusting the amount of eccentricity between the center of rotation of the pistons and the center of rotation of the rotor assembly.

  11. The atomic strain tensor

    SciTech Connect

    Mott, P.H.; Argon, A.S. ); Suter, U.W. Massachusetts Institute of Technology, Cambridge, MA )

    1992-07-01

    A definition of the local atomic strain increments in three dimensions and an algorithm for computing them is presented. An arbitrary arrangement of atoms is tessellated in to Delaunay tetrahedra, identifying interstices, and Voronoi polyhedra, identifying atomic domains. The deformation gradient increment tensor for interstitial space is obtained from the displacement increments of the corner atoms of Delaunay tetrahedra. The atomic site strain increment tensor is then obtained by finding the intersection of the Delaunay tetrahedra with the Voronoi polyhedra, accumulating the individual deformation gradient contributions of the intersected Delaunay tetrahedra into the Voronoi polyhedra. An example application is discussed, showing how the atomic strain clarifies the relative local atomic movement for a polymeric glass treated at the atomic level. 6 refs. 10 figs.

  12. Large-Scale Fabrication of Carbon Nanotube Probe Tips For Atomic Force Microscopy Critical Dimension Imaging Applications

    NASA Technical Reports Server (NTRS)

    Ye, Qi Laura; Cassell, Alan M.; Stevens, Ramsey M.; Meyyappan, Meyya; Li, Jun; Han, Jie; Liu, Hongbing; Chao, Gordon

    2004-01-01

    Carbon nanotube (CNT) probe tips for atomic force microscopy (AFM) offer several advantages over Si/Si3N4 probe tips, including improved resolution, shape, and mechanical properties. This viewgraph presentation discusses these advantages, and the drawbacks of existing methods for fabricating CNT probe tips for AFM. The presentation introduces a bottom up wafer scale fabrication method for CNT probe tips which integrates catalyst nanopatterning and nanomaterials synthesis with traditional silicon cantilever microfabrication technology. This method makes mass production of CNT AFM probe tips feasible, and can be applied to the fabrication of other nanodevices with CNT elements.

  13. Displacement Parameter Inversion for a Novel Electromagnetic Underground Displacement Sensor

    PubMed Central

    Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

    2014-01-01

    Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named “EELA forward modeling-approximate inversion method”. Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0–100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications. PMID:24858960

  14. Displacement parameter inversion for a novel electromagnetic underground displacement sensor.

    PubMed

    Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

    2014-01-01

    Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named "EELA forward modeling-approximate inversion method". Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0-100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications. PMID:24858960

  15. Exact solution for inner displacements of graphene lattice

    SciTech Connect

    Zubko, I. Yu.

    2015-10-27

    It is shown that in the frame of lattice statics approach to finding elastic moduli the homogeneous deformation of graphene monolayer transfers it into the non-equilibrium state. It is necessary to shift part of graphene atoms which form one of its “triangular” sublattices with respect to atoms of another sublattice in order to provide the sample minimum potential energy in a deformed state, while each sublattice is deformed homogeneously. Taking into account these inner displacements of graphene lattice allows obtaining more precise estimations of its elastic moduli. The exact expression for the vector of inner displacements depending on applied deformations and specimen size is found.

  16. First-principles studies on vacancy-modified interstitial diffusion mechanism of oxygen in nickel, associated with large-scale atomic simulation techniques

    SciTech Connect

    Fang, H. Z.; Shang, S. L.; Wang, Y.; Liu, Z. K.; Alfonso, D.; Alman, D. E.; Shin, Y. K.; Zou, C. Y.; Duin, A. C. T. van; Lei, Y. K.; Wang, G. F.

    2014-01-28

    This paper is concerned with the prediction of oxygen diffusivities in fcc nickel from first-principles calculations and large-scale atomic simulations. Considering only the interstitial octahedral to tetrahedral to octahedral minimum energy pathway for oxygen diffusion in fcc lattice, greatly underestimates the migration barrier and overestimates the diffusivities by several orders of magnitude. The results indicate that vacancies in the Ni-lattice significantly impact the migration barrier of oxygen in nickel. Incorporation of the effect of vacancies results in predicted diffusivities consistent with available experimental data. First-principles calculations show that at high temperatures the vacancy concentration is comparable to the oxygen solubility, and there is a strong binding energy and a redistribution of charge density between the oxygen atom and vacancy. Consequently, there is a strong attraction between the oxygen and vacancy in the Ni lattice, which impacts diffusion.

  17. Development of a high dynamic range spectroscopic system for observation of neutral hydrogen atom density distribution in Large Helical Device core plasma

    SciTech Connect

    Fujii, K. Atsumi, S.; Watanabe, S.; Shikama, T.; Hasuo, M.; Goto, M.; Morita, S.

    2014-02-15

    We report development of a high dynamic range spectroscopic system comprising a spectrometer with 30% throughput and a camera with a low-noise fast-readout complementary metal-oxide semiconductor sensor. The system achieves a 10{sup 6} dynamic range (∼20 bit resolution) and an instrumental function approximated by a Voigt profile with Gauss and Lorentz widths of 31 and 0.31 pm, respectively, for 656 nm light. The application of the system for line profile observations of the Balmer-α emissions from high temperature plasmas generated in the Large Helical Device is also presented. In the observed line profiles, emissions are detected in far wings more than 1.0 nm away from the line center, equivalent to neutral hydrogen atom kinetic energies above 1 keV. We evaluate atom density distributions in the core plasma by analyzing the line profiles.

  18. Electron density and transport in top-gated graphene nanoribbon devices: First-principles Green function algorithms for systems containing a large number of atoms

    NASA Astrophysics Data System (ADS)

    Areshkin, Denis A.; Nikolić, Branislav K.

    2010-04-01

    The recent fabrication of graphene nanoribbon (GNR) field-effect transistors poses a challenge for first-principles modeling of carbon nanoelectronics due to many thousand atoms present in the device. The state of the art quantum transport algorithms, based on the nonequilibrium Green function formalism combined with the density-functional theory (NEGF-DFT), were originally developed to calculate self-consistent electron density in equilibrium and at finite bias voltage (as a prerequisite to obtain conductance or current-voltage characteristics, respectively) for small molecules attached to metallic electrodes where only a few hundred atoms are typically simulated. Here we introduce combination of two numerically efficient algorithms which make it possible to extend the NEGF-DFT framework to device simulations involving large number of atoms. Our first algorithm offers an alternative to the usual evaluation of the equilibrium part of electron density via numerical contour integration of the retarded Green function in the upper complex half-plane. It is based on the replacement of the Fermi function f(E) with an analytic function f˜(E) coinciding with f(E) inside the integration range along the real axis, but decaying exponentially in the upper complex half-plane. Although f˜(E) has infinite number of poles, whose positions and residues are determined analytically, only a finite number of those poles have non-negligible residues. We also discuss how this algorithm can be extended to compute the nonequilibrium contribution to electron density, thereby evading cumbersome real-axis integration (within the bias voltage window) of NEGFs which is very difficult to converge for systems with large number of atoms while maintaining current conservation. Our second algorithm combines the recursive formulas with the geometrical partitioning of an arbitrary multiterminal device into nonuniform segments in order to reduce the computational complexity of the retarded Green

  19. Large-scale analysis of high-speed atomic force microscopy data sets using adaptive image processing

    PubMed Central

    Erickson, Blake W; Coquoz, Séverine; Adams, Jonathan D; Burns, Daniel J

    2012-01-01

    Summary Modern high-speed atomic force microscopes generate significant quantities of data in a short amount of time. Each image in the sequence has to be processed quickly and accurately in order to obtain a true representation of the sample and its changes over time. This paper presents an automated, adaptive algorithm for the required processing of AFM images. The algorithm adaptively corrects for both common one-dimensional distortions as well as the most common two-dimensional distortions. This method uses an iterative thresholded processing algorithm for rapid and accurate separation of background and surface topography. This separation prevents artificial bias from topographic features and ensures the best possible coherence between the different images in a sequence. This method is equally applicable to all channels of AFM data, and can process images in seconds. PMID:23213638

  20. How large are post-CCSD(T) contributions to the total atomization energies of medium-sized alkanes?

    NASA Astrophysics Data System (ADS)

    Karton, Amir

    2016-02-01

    The CCSD(T) method is often considered as the gold standard in quantum chemistry for single-reference systems. Using W4 and W4lite theories, we calculate post-CCSD(T) contributions to the total atomization energies (TAEs) of n-alkanes and show that they reach up to 0.65 kcal/mol for n-hexane. Furthermore, we find that post-CCSD(T) contributions increase linearly with the size of the n-alkane, indicating that they will reach ∼1 kcal/mol for n-decane (C10H22) and ∼2 kcal/mol for n-icosane (C20H42). These results are significant since today CCSD(T)/CBS-type methods are being applied to hydrocarbons of increasing size and are assumed to give TAEs with chemical accuracy for these systems.

  1. Site Change of Hydrogen in Niobium on Alloying with Oversized Ta Atoms

    NASA Astrophysics Data System (ADS)

    Yagi, Eiichi; Yoshii, Motoyasu; Okada, Yoshinori; Matsuba, Hiroshi; Miyahara, Kazuya; Koike, Shigetoshi; Sugawara, Takamasa; Shishido, Toetsu; Ogiwara, Kiyoshi

    2009-06-01

    In order to clarify a difference in hydrogen interaction with oversized solute atoms and with undersized solute atoms in bcc metals in the low solute concentration region, the site occupancy of hydrogen in Nb alloyed with 5 at. % of oversized Ta atoms has been studied at room temperature for hydrogen concentrations of 0.018 and 0.025 at the hydrogen-to-metal-atom ratio (CH=[H]/[M]) by the channelling method utilizing a nuclear reaction 1H(11B,α)αα with a 11B beam of an energy of 2.03 MeV. Clearly different from the result on hydrogen in Nb alloyed with undersized Mo atoms, in both specimens H atoms are distributed over tetrahedral (T) sites and the displaced-T sites (d-T sites) which are displaced from T sites by about 0.25 Å towards their nearest neighbour octahedral (O) sites. The T site is more favourable for hydrogen occupancy, but the number of available T sites is limited, and excess H atoms occupy the d-T sites. Therefore, in contrast to a strong attractive interaction between hydrogen and undersized Mo atoms (trapping), there exists no such a strong attractive interaction between hydrogen and oversized Ta atoms. It is considered that the trapping of hydrogen by undersized solute atoms is effective to the large enhancement of the terminal solubility of hydrogen (TSH) on alloying with undersized solute atoms, at least, in the low solute concentration region.

  2. Atomic resolution holography.

    PubMed

    Hayashi, Kouichi

    2014-11-01

    Atomic resolution holography, such as X-ray fluorescence holography (XFH)[1] and photoelectron holography (PH), has the attention of researcher as an informative local structure analysis, because it provides three dimensional atomic images around specific elements within a range of a few nanometers. It can determine atomic arrangements around a specific element without any prior knowledge of structures. It is considered that the atomic resolution holographic is a third method of structural analysis at the atomic level after X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS). As known by many researchers, XRD and XAFS are established methods that are widespread use in various fields. XRD and XAFS provide information on long-range translational periodicities and very local environments, respectively, whereas the atomic resolution holography gives 3D information on the local order and can visualize surrounding atoms with a large range of coordination shells. We call this feature "3D medium-range local structure observation".In addition to this feature, the atomic resolution holography is very sensitive to the displacement of atoms from their ideal positions, and one can obtain quantitative information about local lattice distortions by analyzing reconstructed atomic images[2] When dopants with different atomic radii from the matrix elements are present, the lattices around the dopants are distorted. However, using the conventional methods of structural analysis, one cannot determine the extent to which the local lattice distortions are preserved from the dopants. XFH is a good tool for solving this problem.Figure 1 shows a recent achievement on a relaxor ferroelectric of Pb(Mg1/3Nb2/3)O3 (PMN) using XFH. The structural studies of relaxor ferroelectrics have been carried out by X-ray or neutron diffractions, which suggested rhombohedral distortions of their lattices. However, their true pictures have not been obtained, yet. The Nb Kα holograms showed

  3. DNA nanotechnology. Programming colloidal phase transitions with DNA strand displacement.

    PubMed

    Rogers, W Benjamin; Manoharan, Vinothan N

    2015-02-01

    DNA-grafted nanoparticles have been called "programmable atom-equivalents": Like atoms, they form three-dimensional crystals, but unlike atoms, the particles themselves carry information (the sequences of the grafted strands) that can be used to "program" the equilibrium crystal structures. We show that the programmability of these colloids can be generalized to the full temperature-dependent phase diagram, not just the crystal structures themselves. We add information to the buffer in the form of soluble DNA strands designed to compete with the grafted strands through strand displacement. Using only two displacement reactions, we program phase behavior not found in atomic systems or other DNA-grafted colloids, including arbitrarily wide gas-solid coexistence, reentrant melting, and even reversible transitions between distinct crystal phases. PMID:25657244

  4. Atomic Calligraphy

    NASA Astrophysics Data System (ADS)

    Imboden, Matthias; Pardo, Flavio; Bolle, Cristian; Han, Han; Tareen, Ammar; Chang, Jackson; Christopher, Jason; Corman, Benjamin; Bishop, David

    2013-03-01

    Here we present a MEMS based method to fabricate devices with a small number of atoms. In standard semiconductor fabrication, a large amount of material is deposited, after which etching removes what is not wanted. This technique breaks down for structures that approach the single atom limit, as it is inconceivable to etch away all but one atom. What is needed is a bottom up method with single or near single atom precision. We demonstrate a MEMS device that enables nanometer position controlled deposition of gold atoms. A digitally driven plate is swept as a flux of gold atoms passes through an aperture. Appling voltages on four comb capacitors connected to the central plate by tethers enable nanometer lateral precision in the xy plane over 15x15 sq. microns. Typical MEMS structures have manufacturing resolutions on the order of a micron. Using a FIB it is possible to mill apertures as small as 10 nm in diameter. Assuming a low incident atomic flux, as well as an integrated MEMS based shutter with microsecond response time, it becomes possible to deposit single atoms. Due to their small size and low power consumption, such nano-printers can be mounted directly in a cryogenic system at ultrahigh vacuum to deposit clean quench condensed metallic structures.

  5. Large increase in the electron capture and excitation cross sections for Li+ colliding with atomic H under UV laser assistance

    NASA Astrophysics Data System (ADS)

    Domínguez-Gutiérrez, F. J.; Cabrera-Trujillo, R.

    2015-07-01

    Neutralization and ash products due to electron capture processes in plasmas reduce the efficiency of energy generation in fusion Tokamak reactors. Therefore, lithium ions have been used to improve the efficiency of energy generation where good control of the electron capture process is required. Here, we show that an intense (1.4× {{10}13} W cm-2), ultra-short (1 fs at full width half-maximum) Gaussian laser pulse in the UV region can enhance the electron capture process on L{{i}+}+H(1s) in the low collision keV energy region. We find a factor of 10 enhancement in electron capture cross-section at impact energies lower than 10 keV amu-1 for an 80 nm wavelength laser and a factor of 2 for the excitation process in the hydrogen atom as compared to the laser-free case. In contrast, for a 200 nm wavelength laser the increase of the electron capture cross-sections takes place around 1 keV amu-1 by a factor of 3 and no enhancement for the excitation process. Our results show that the UV assisted production of Li can be controlled, particularly for short UV wave-length for a specific collision energy range. We anticipate that our findings will facilitate UV laser control of the Li production in Tokamak reactors and encourage further experimental work in this system.

  6. Displacement, Substitution, Sublimation: A Bibliography.

    ERIC Educational Resources Information Center

    Pedrini, D. T.; Pedrini, Bonnie C.

    Sigmund Freund worked with the mechanisms of displacement, substitution, and sublimation. These mechanisms have many similarities and have been studied diagnostically and therapeutically. Displacement and substitution seem to fit in well with phobias, hysterias, somatiyations, prejudices, and scapegoating. Phobias, prejudices, and scapegoating…

  7. Insect Wing Displacement Measurement Using Digital Holography

    SciTech Connect

    Aguayo, Daniel D.; Mendoza Santoyo, Fernando; Torre I, Manuel H. de la; Caloca Mendez, Cristian I.

    2008-04-15

    Insects in flight have been studied with optical non destructive techniques with the purpose of using meaningful results in aerodynamics. With the availability of high resolution and large dynamic range CCD sensors the so called interferometric digital holographic technique was used to measure the surface displacement of in flight insect wings, such as butterflies. The wings were illuminated with a continuous wave Verdi laser at 532 nm, and observed with a CCD Pixelfly camera that acquire images at a rate of 11.5 frames per second at a resolution of 1392x1024 pixels and 12 Bit dynamic range. At this frame rate digital holograms of the wings were captured and processed in the usual manner, namely, each individual hologram is Fourier processed in order to find the amplitude and phase corresponding to the digital hologram. The wings displacement is obtained when subtraction between two digital holograms is performed for two different wings position, a feature applied to all consecutive frames recorded. The result of subtracting is seen as a wrapped phase fringe pattern directly related to the wing displacement. The experimental data for different butterfly flying conditions and exposure times are shown as wire mesh plots in a movie of the wings displacement.

  8. Atomic Disorder in Tetrahedrite

    NASA Astrophysics Data System (ADS)

    Salasin, John Robert; Chakoumakos, Bryan; Rawn, Claudia; May, Andrew; Lara-Curzio, Edgar; McGuire, Michael; Cao, Huibo

    2015-03-01

    Thermoelectrics (TE) are materials which turn heat energy into electrical energy with applications spanning multiple disciplines including space exploration, Peltier cooling, and engine efficiency. Tetrahedrite is a copper sulfosalt with the general formula Cu12-xMx(Sb,As)4S13. Where M denotes a Cu2+ site frequently replaced in natural tetrahedrite with Zn, Fe, Hg, or Mn. It has a cubic structure with an I-43m symmetry, a = 10.4 Å, and only a handful of adjustable parameters. This structural study corroborates theoretical calculations on atomic disorder. Positional disorder of the trigonally coordinated Cu(2) site is suggested from the temperature dependence of the atomic displacement parameters determine from single-crystal x-ray and neutron diffraction. The displacements are extremely anisotropic for Cu(2) with a maximum rms static displacement of ~ 0.25 Å.

  9. Million atom DFT calculations using coarse graining and petascale computing

    NASA Astrophysics Data System (ADS)

    Nicholson, Don; Odbadrakh, Kh.; Samolyuk, G. D.; Stoller, R. E.; Zhang, X. G.; Stocks, G. M.

    2014-03-01

    Researchers performing classical Molecular Dynamics (MD) on defect structures often find it necessary to use millions of atoms in their models. It would be useful to perform density functional calculations on these large configurations in order to observe electron-based properties such as local charge and spin and the Helmann-Feynman forces on the atoms. The great number of atoms usually requires that a subset be ``carved'' from the configuration and terminated in a less that satisfactory manner, e.g. free space or inappropriate periodic boundary conditions. Coarse graining based on the Locally Self-consistent Multiple Scattering method (LSMS) and petascale computing can circumvent this problem by treating the whole system but dividing the atoms into two groups. In Coarse Grained LSMS (CG-LSMS) one group of atoms has its charge and scattering determined prescriptively based on neighboring atoms while the remaining group of atoms have their charge and scattering determined according to DFT as implemented in the LSMS. The method will be demonstrated for a one-million-atom model of a displacement cascade in Fe for which 24,130 atoms are treated with full DFT and the remaining atoms are treated prescriptively. Work supported as part of Center for Defect Physics, an Energy Frontier Research Center funded by the U.S. DOE, Office of Science, Basic Energy Sciences, used Oak Ridge Leadership Computing Facility, Oak Ridge National Lab, of DOE Office of Science.

  10. Low frequency magnetic field suppression in an atomic spin co-magnetometer with a large electron magnetic field

    NASA Astrophysics Data System (ADS)

    Fang, Jiancheng; Chen, Yao; Zou, Sheng; Liu, Xuejing; Hu, Zhaohui; Quan, Wei; Yuan, Heng; Ding, Ming

    2016-03-01

    In a K-Rb-21Ne co-magnetometer, the Rb electron magnetic field which is experienced by the nuclear spin is about 100 times larger than that of the K in a K-3He co-magnetometer. The large electron magnetic field which is neglected in the K-3He co-magnetometer coupled Bloch equations model is considered here in the K-Rb-21Ne co-magnetometer to study the low frequency magnetic field suppression effect. Theoretical analysis and experimental results shows that in the K-Rb-21Ne spin co-magnetometer, not only the nuclear spin but also the large electron spin magnetic field compensate the external magnetic field noise. By comparison, only the 3He nuclear spins mainly compensate the external magnetic field noise in a K-3He co-magnetometer. With this study, in addition to just increasing the magnetic field of the nuclear spins, we can suppress the magnetic field noise by increasing the density of the electron spin. We also studied how the magnetic field suppression effect relates to the scale factor of the K-Rb-21Ne co-magnetometer and we compared the scale factor with that of the K-3He co-magnetometer. Lastly, we show the sensitivity of our co-magnetometer. The magnetic field noise, the air density fluctuation noise and pumping power optimization are studied to improve the sensitivity of the co-magnetometer.

  11. Regenerative rotary displacer Stirling engine

    SciTech Connect

    Isshiki, Naotsugu; Watanabe, Hiroichi; Raggi, L.; Isshiki, Seita; Hirata, Koichi

    1996-12-31

    A few rotary displacer Stirling engines in which the displacer has one gas pocket space at one side and rotates in a main enclosed cylinder, which is heated from one side and cooled from opposite side without any regenerator, have been studied for some time by the authors. The authors tried to improve this engine by equipping it with a regenerator, because without a regenerator, pressure oscillation and efficiency are too small. Here, several types of regenerative rotary displacer piston Stirling engines are proposed. One is the contra-rotating tandem two disc type displacer engine using axial heat conduction through side walls or by heat pipes and another is a single disc type with circulating fluid regenerator or heat pipes. Stirling engines of this new rotary displacer type are thought to attain high speed. Here, experimental results of the original rotary displacer Stirling engine without a regenerator, and one contra-rotating tandem displacer engine with side wall regenerator by axial heat conduction are reported accompanied with a discussion of the results.

  12. Gamma rays from atomic and molecular gas in the large complex of clouds in Orion and Monoceros

    NASA Technical Reports Server (NTRS)

    Bloemen, J. B. G. M.; Caraveo, P. A.; Hermsen, W.; Lebrun, F.; Maddalena, R. J.; Strong, A. W.; Thaddeus, P.

    1984-01-01

    A comparison of COS-B gamma-ray observations of the large complex of interstellar clouds in Orion and Monoceros with the Columbia CO and Berkeley H I surveys of this region reveals a good correlation between gamma-ray emission and total gas distribution. The observed gamma-ray emission is explainable in terms of interactions of cosmic rays that are uniformly distributed in this region with the interstellar gas. The correlation is used as the basis of a calibration of the ratio between H2 column density and the integrated CO line intensity; the value of (2.6 + or - 1.2) X 10 to the 20th mol/sq cm K km s thereby obtained is consistent with the value derived from a similar analysis for the inner galaxy.

  13. Atomic structure from large-area, low-dose exposures of materials: A new route to circumvent radiation damage☆

    PubMed Central

    Meyer, J.C.; Kotakoski, J.; Mangler, C.

    2014-01-01

    Beam-induced structural modifications are a major nuisance in the study of materials by high-resolution electron microscopy. Here, we introduce a new approach to circumvent the radiation damage problem by a statistical treatment of large, noisy, low-dose data sets of non-periodic configurations (e.g. defects) in the material. We distribute the dose over a mixture of different defect structures at random positions and with random orientations, and recover representative model images via a maximum likelihood search. We demonstrate reconstructions from simulated images at such low doses that the location of individual entities is not possible. The approach may open a route to study currently inaccessible beam-sensitive configurations. PMID:24315660

  14. Borehole optical lateral displacement sensor

    DOEpatents

    Lewis, R.E.

    1998-10-20

    There is provided by this invention an optical displacement sensor that utilizes a reflective target connected to a surface to be monitored to reflect light from a light source such that the reflected light is received by a photoelectric transducer. The electric signal from the photoelectric transducer is then imputed into electronic circuitry to generate an electronic image of the target. The target`s image is monitored to determine the quantity and direction of any lateral displacement in the target`s image which represents lateral displacement in the surface being monitored. 4 figs.

  15. Limitations on the extent of off-center displacements in TbMnO3 from EXAFS measurements

    NASA Astrophysics Data System (ADS)

    Bridges, F.; Downs, C.; O'Brien, T.; Jeong, Il-K.; Kimura, T.

    2007-09-01

    We present extended x-ray-absorption fine structure (EXAFS) data at the MnK and TbL3 edges that provide upper limits on the possible displacements of any atoms in TbMnO3 . The displacements must be less than 0.005 0.01Å for all atoms, which eliminates the possibility of moderate distortions (0.02Å) with a small c -axis component, but for which the displacements in the ab plane average to zero. Assuming the polarization arises from a displacement of the O2 atoms along the c axis, the measured polarization then leads to an O2 displacement that is at least 6×10-4Å , well below our experimental limit. Thus, a combination of the EXAFS and the measured electrical polarization indicate that the atomic displacements likely lie in the range 6×10-4 5×10-3Å .

  16. Early Science with the Large Millimeter Telescope: COOL BUDHIES I - a pilot study of molecular and atomic gas at z ≃ 0.2

    NASA Astrophysics Data System (ADS)

    Cybulski, Ryan; Yun, Min S.; Erickson, Neal; De la Luz, Victor; Narayanan, Gopal; Montaña, Alfredo; Sánchez, David; Zavala, Jorge A.; Zeballos, Milagros; Chung, Aeree; Fernández, Ximena; van Gorkom, Jacqueline; Haines, Chris P.; Jaffé, Yara L.; Montero-Castaño, María; Poggianti, Bianca M.; Verheijen, Marc A. W.; Yoon, Hyein; Deshev, Boris Z.; Harrington, Kevin; Hughes, David H.; Morrison, Glenn E.; Schloerb, F. Peter; Velazquez, Miguel

    2016-04-01

    An understanding of the mass build-up in galaxies over time necessitates tracing the evolution of cold gas (molecular and atomic) in galaxies. To that end, we have conducted a pilot study called CO Observations with the LMT of the Blind Ultra-Deep H I Environment Survey (COOL BUDHIES). We have observed 23 galaxies in and around the two clusters Abell 2192 (z = 0.188) and Abell 963 (z = 0.206), where 12 are cluster members and 11 are slightly in the foreground or background, using about 28 total hours on the Redshift Search Receiver (RSR) on the Large Millimeter Telescope (LMT) to measure the 12CO J = 1 → 0 emission line and obtain molecular gas masses. These new observations provide a unique opportunity to probe both the molecular and atomic components of galaxies as a function of environment beyond the local Universe. For our sample of 23 galaxies, nine have reliable detections (S/N ≥ 3.6) of the 12CO line, and another six have marginal detections (2.0 < S/N < 3.6). For the remaining eight targets we can place upper limits on molecular gas masses roughly between 109 and 1010 M⊙. Comparing our results to other studies of molecular gas, we find that our sample is significantly more abundant in molecular gas overall, when compared to the stellar and the atomic gas component, and our median molecular gas fraction lies about 1σ above the upper limits of proposed redshift evolution in earlier studies. We discuss possible reasons for this discrepancy, with the most likely conclusion being target selection and Eddington bias.

  17. Early Science with the Large Millimeter Telescope: COOL BUDHIES I - a pilot study of molecular and atomic gas at z ≃ 0.2

    NASA Astrophysics Data System (ADS)

    Cybulski, Ryan; Yun, Min S.; Erickson, Neal; De la Luz, Victor; Narayanan, Gopal; Montaña, Alfredo; Sánchez, David; Zavala, Jorge A.; Zeballos, Milagros; Chung, Aeree; Fernández, Ximena; van Gorkom, Jacqueline; Haines, Chris P.; Jaffé, Yara L.; Montero-Castaño, María; Poggianti, Bianca M.; Verheijen, Marc A. W.; Yoon, Hyein; Deshev, Boris Z.; Harrington, Kevin; Hughes, David H.; Morrison, Glenn E.; Schloerb, F. Peter; Velazquez, Miguel

    2016-07-01

    An understanding of the mass build-up in galaxies over time necessitates tracing the evolution of cold gas (molecular and atomic) in galaxies. To that end, we have conducted a pilot study called CO Observations with the LMT of the Blind Ultra-Deep H I Environment Survey (COOL BUDHIES). We have observed 23 galaxies in and around the two clusters Abell 2192 (z = 0.188) and Abell 963 (z = 0.206), where 12 are cluster members and 11 are slightly in the foreground or background, using about 28 total hours on the Redshift Search Receiver on the Large Millimeter Telescope (LMT) to measure the 12CO J = 1 → 0 emission line and obtain molecular gas masses. These new observations provide a unique opportunity to probe both the molecular and atomic components of galaxies as a function of environment beyond the local Universe. For our sample of 23 galaxies, nine have reliable detections (S/N ≥ 3.6) of the 12CO line, and another six have marginal detections (2.0 < S/N < 3.6). For the remaining eight targets we can place upper limits on molecular gas masses roughly between 109 and 1010 M⊙. Comparing our results to other studies of molecular gas, we find that our sample is significantly more abundant in molecular gas overall, when compared to the stellar and the atomic gas component, and our median molecular gas fraction lies about 1σ above the upper limits of proposed redshift evolution in earlier studies. We discuss possible reasons for this discrepancy, with the most likely conclusion being target selection and Eddington bias.

  18. Polyimidazoles Via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W.; Hergenrother, Paul M.

    1990-01-01

    Experiments show variety of polyimidazoles prepared by aromatic nucleophilic displacement, from reactions of bisphenol imidazoles with activated difluoro compounds. Polyimidazoles have good mechanical properties making them suitable for use as films, moldings, and adhesives.

  19. Displacement sensing system and method

    DOEpatents

    VunKannon, Jr., Robert S

    2006-08-08

    A displacement sensing system and method addresses demanding requirements for high precision sensing of displacement of a shaft, for use typically in a linear electro-dynamic machine, having low failure rates over multi-year unattended operation in hostile environments. Applications include outer space travel by spacecraft having high-temperature, sealed environments without opportunity for servicing over many years of operation. The displacement sensing system uses a three coil sensor configuration, including a reference and sense coils, to provide a pair of ratio-metric signals, which are inputted into a synchronous comparison circuit, which is synchronously processed for a resultant displacement determination. The pair of ratio-metric signals are similarly affected by environmental conditions so that the comparison circuit is able to subtract or nullify environmental conditions that would otherwise cause changes in accuracy to occur.

  20. Self-compensating displacement sensor based on hydramatic structured transducer and fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Chen, Shimeng; Liu, Yun; Liu, Xiuxin; Zhang, Yang; Peng, Wei

    2015-12-01

    An optical fiber displacement sensor with a large measuring range for simultaneous displacement and temperature measurement is presented in this paper. We developed a specific transducer based on the piston and hydraumatic structure to realize a large displacement measurement, which combined the large measuring range and high precision into a single sensor system. The spectrum showed two reflection peaks used to compensate for cross-sensitivity in the displacement detection. This displacement sensor can linearly work in a large measuring displacement range greater than 45 mm with a high sensitivity of 0.036 nm/mm. The sensor we reported can be developed for real-time displacement monitoring in many industrial environments such as the mechanical shape or liquid level monitoring.

  1. Unraveling low-resolution structural data of large biomolecules by constructing atomic models with experiment-targeted parallel cascade selection simulations

    NASA Astrophysics Data System (ADS)

    Peng, Junhui; Zhang, Zhiyong

    2016-07-01

    Various low-resolution experimental techniques have gained more and more popularity in obtaining structural information of large biomolecules. In order to interpret the low-resolution structural data properly, one may need to construct an atomic model of the biomolecule by fitting the data using computer simulations. Here we develop, to our knowledge, a new computational tool for such integrative modeling by taking the advantage of an efficient sampling technique called parallel cascade selection (PaCS) simulation. For given low-resolution structural data, this PaCS-Fit method converts it into a scoring function. After an initial simulation starting from a known structure of the biomolecule, the scoring function is used to pick conformations for next cycle of multiple independent simulations. By this iterative screening-after-sampling strategy, the biomolecule may be driven towards a conformation that fits well with the low-resolution data. Our method has been validated using three proteins with small-angle X-ray scattering data and two proteins with electron microscopy data. In all benchmark tests, high-quality atomic models, with generally 1–3 Å from the target structures, are obtained. Since our tool does not need to add any biasing potential in the simulations to deform the structure, any type of low-resolution data can be implemented conveniently.

  2. Unraveling low-resolution structural data of large biomolecules by constructing atomic models with experiment-targeted parallel cascade selection simulations

    PubMed Central

    Peng, Junhui; Zhang, Zhiyong

    2016-01-01

    Various low-resolution experimental techniques have gained more and more popularity in obtaining structural information of large biomolecules. In order to interpret the low-resolution structural data properly, one may need to construct an atomic model of the biomolecule by fitting the data using computer simulations. Here we develop, to our knowledge, a new computational tool for such integrative modeling by taking the advantage of an efficient sampling technique called parallel cascade selection (PaCS) simulation. For given low-resolution structural data, this PaCS-Fit method converts it into a scoring function. After an initial simulation starting from a known structure of the biomolecule, the scoring function is used to pick conformations for next cycle of multiple independent simulations. By this iterative screening-after-sampling strategy, the biomolecule may be driven towards a conformation that fits well with the low-resolution data. Our method has been validated using three proteins with small-angle X-ray scattering data and two proteins with electron microscopy data. In all benchmark tests, high-quality atomic models, with generally 1–3 Å from the target structures, are obtained. Since our tool does not need to add any biasing potential in the simulations to deform the structure, any type of low-resolution data can be implemented conveniently. PMID:27377017

  3. Unraveling low-resolution structural data of large biomolecules by constructing atomic models with experiment-targeted parallel cascade selection simulations.

    PubMed

    Peng, Junhui; Zhang, Zhiyong

    2016-01-01

    Various low-resolution experimental techniques have gained more and more popularity in obtaining structural information of large biomolecules. In order to interpret the low-resolution structural data properly, one may need to construct an atomic model of the biomolecule by fitting the data using computer simulations. Here we develop, to our knowledge, a new computational tool for such integrative modeling by taking the advantage of an efficient sampling technique called parallel cascade selection (PaCS) simulation. For given low-resolution structural data, this PaCS-Fit method converts it into a scoring function. After an initial simulation starting from a known structure of the biomolecule, the scoring function is used to pick conformations for next cycle of multiple independent simulations. By this iterative screening-after-sampling strategy, the biomolecule may be driven towards a conformation that fits well with the low-resolution data. Our method has been validated using three proteins with small-angle X-ray scattering data and two proteins with electron microscopy data. In all benchmark tests, high-quality atomic models, with generally 1-3 Å from the target structures, are obtained. Since our tool does not need to add any biasing potential in the simulations to deform the structure, any type of low-resolution data can be implemented conveniently. PMID:27377017

  4. A novel linear displacement sensor

    NASA Astrophysics Data System (ADS)

    Yang, Ji-sen; Zhang, Jing; Chen, Xi-hou; Zhang, Tian-heng

    2011-12-01

    With development of time grating technology in the past 10 years, the theory of using time to measure spatial displacement has been completed greatly. In the study of time grating, one novel linear displacement sensor is proposed based on the measurement principles of time grating. The measurement principles of linear displacement are similar to that of angular displacement. Both of them need one endless coordinate with uniform velocity. The theory of linear AC motor is used, and the three-phase winding with equal division space of 120° and three-phase exciting signal with uniform time are utilized to generate the endless moving coordinate with uniform velocity. The magnetic traveling wave arises from the left endpoint and disappears in the right endpoint, and it travels pole pitch distance of W during the periodic time of T with the uniform velocity. When magnetic traveling wave passes by the static probe and the moving probe, the electric signals will be induced on the winding, respectively. Therefore, the linear displacement can be achieved by comparing the phase between the two output induced signals from he static probe and the moving probe. Furthermore, in order to improve the machining technique, four kinds of winding framework are designed to employ. The experimental results show that advantages and disadvantages both exist in the design methods and the precision of experiment results reaches +/-2µm. The next study plan is to choose the most excellent design method through further experiments and improve the precision of displacement sensor greatly.

  5. Small Atomic Orbital Basis Set First-Principles Quantum Chemical Methods for Large Molecular and Periodic Systems: A Critical Analysis of Error Sources.

    PubMed

    Sure, Rebecca; Brandenburg, Jan Gerit; Grimme, Stefan

    2016-04-01

    In quantum chemical computations the combination of Hartree-Fock or a density functional theory (DFT) approximation with relatively small atomic orbital basis sets of double-zeta quality is still widely used, for example, in the popular B3LYP/6-31G* approach. In this Review, we critically analyze the two main sources of error in such computations, that is, the basis set superposition error on the one hand and the missing London dispersion interactions on the other. We review various strategies to correct those errors and present exemplary calculations on mainly noncovalently bound systems of widely varying size. Energies and geometries of small dimers, large supramolecular complexes, and molecular crystals are covered. We conclude that it is not justified to rely on fortunate error compensation, as the main inconsistencies can be cured by modern correction schemes which clearly outperform the plain mean-field methods. PMID:27308221

  6. Small Atomic Orbital Basis Set First‐Principles Quantum Chemical Methods for Large Molecular and Periodic Systems: A Critical Analysis of Error Sources

    PubMed Central

    Sure, Rebecca; Brandenburg, Jan Gerit

    2015-01-01

    Abstract In quantum chemical computations the combination of Hartree–Fock or a density functional theory (DFT) approximation with relatively small atomic orbital basis sets of double‐zeta quality is still widely used, for example, in the popular B3LYP/6‐31G* approach. In this Review, we critically analyze the two main sources of error in such computations, that is, the basis set superposition error on the one hand and the missing London dispersion interactions on the other. We review various strategies to correct those errors and present exemplary calculations on mainly noncovalently bound systems of widely varying size. Energies and geometries of small dimers, large supramolecular complexes, and molecular crystals are covered. We conclude that it is not justified to rely on fortunate error compensation, as the main inconsistencies can be cured by modern correction schemes which clearly outperform the plain mean‐field methods. PMID:27308221

  7. Cold Atoms

    NASA Astrophysics Data System (ADS)

    Bellac, Michel Le

    2014-11-01

    This chapter and the following one address collective effects of quantum particles, that is, the effects which are observed when we put together a large number of identical particles, for example, electrons, helium-4 or rubidium-85 atoms. We shall see that quantum particles can be classified into two categories, bosons and fermions, whose collective behavior is radically different. Bosons have a tendency to pile up in the same quantum state, while fermions have a tendency to avoid each other. We say that bosons and fermions obey two different quantum statistics, the Bose-Einstein and the Fermi-Dirac statistics, respectively. Temperature is a collective effect, and in Section 5.1 we shall explain the concept of absolute temperature and its relation to the average kinetic energy of molecules. We shall describe in Section 5.2 how we can cool atoms down thanks to the Doppler effect, and explain how cold atoms can be used to improve the accuracy of atomic clocks by a factor of about 100. The effects of quantum statistics are prominent at low temperatures, and atom cooling will be used to obtain Bose-Einstein condensates at low enough temperatures, when the atoms are bosons.

  8. A Robust Ramsey Interferometer for Atomic Timekeeping in Dynamic Environments

    NASA Astrophysics Data System (ADS)

    Kotru, Krish; Brown, Justin; Butts, David; Choy, Jennifer; Galfond, Marissa; Johnson, David M.; Kinast, Joseph; Timmons, Brian; Stoner, Richard

    2014-05-01

    We present a laser-based approach to atomic timekeeping, in which atomic phase information is extracted using modified Raman pulses in a Ramsey sequence. We overcome systematic effects associated with differential AC Stark shifts by employing atom optics derived from Raman adiabatic rapid passage (ARP). ARP drives coherent transfer between two hyperfine ground states by sweeping the frequency difference of two optical fields and maintaining a large single-photon detuning. Compared to resonant, pulsed Raman transitions, ARP atom optics afford a >150x reduction in sensitivity to differential AC Stark shifts in a Ramsey interferometer. We also demonstrate that ARP preserves fringe contrast in Ramsey interferometers for cloud displacements reaching the 1/e2 intensity radius of the laser beam. ARP can thus be expected to improve the robustness of clock interferometers operating in dynamic environments. Copyright ©2014 by The Charles Stark Draper Laboratory, Inc. All rights reserved.

  9. Competitive adsorption, displacement, and transport of organic matter on iron oxide: II. Displacement and transport

    SciTech Connect

    Gu, B; Mehlhorn, T.L.; Liang, Liyuan

    1996-08-01

    The competitive interactions between organic matter compounds and mineral surfaces are poorly understood, yet these interactions may play a significant role in the stability and co-transport of mineral colloids and/or environmental contaminants. In this study, the processes of competitive adsorption, displacement, and transport of Suwannee River natural organic matter (SR-NOM) are investigated with several model organic compounds in packed beds of iron oxide-coated quartz columns. Results demonstrated that strongly-binding organic compounds are competitively adsorbed and displace those weakly-bound organic compounds along the flow path. Among the four organic compounds studied, polyacrylic acid (PAA) appeared to be the most competitive, whereas SR-NOM was more competitive than phthalic and salicylic acids. A diffuse adsorption and sharp desorption front (giving an appearance of irreversible adsorption) of the SR-NOM breakthrough curves are explained as being a result of the competitive time-dependent adsorption and displacement processes between different organic components within the SR-NOM. The stability and transport of iron oxide colloids varied as one organic component competitively displaces another. Relatively large quantities of iron oxide colloids are transported when the more strongly-binding PAA competitively displaces the weakly-binding SR-NOM or when SR-NOM competitively displaces phthalic and salicylic acids. Results of this study suggest that the chemical composition and hence the functional behavior of NOM (e.g., in stabilizing mineral colloids and in complexing contaminants) can change along its flow path as a result of the dynamic competitive interactions between heterogeneous NOM subcomponents. Further studies are needed to better define and quantify these NOM components as well as their roles in contaminant partitioning and transport. 37 refs., 10 figs.

  10. Measurement of axial injection displacement with trim coil current unbalance

    SciTech Connect

    Covo, Michel Kireeff

    2014-08-15

    The Dee probe used for measuring internal radial beam intensity shows large losses inside the radius of 20 cm of the 88 in. cyclotron. The current of the top and bottom innermost trim coil 1 is unbalanced to study effects of the axial injection displacement. A beam profile monitor images the ion beam bunches, turn by turn. The experimental bunch center of mass position is compared with calculations of the magnetic mirror effect displacement and shows good agreement.

  11. Measurement of axial injection displacement with trim coil current unbalance

    NASA Astrophysics Data System (ADS)

    Covo, Michel Kireeff

    2014-08-01

    The Dee probe used for measuring internal radial beam intensity shows large losses inside the radius of 20 cm of the 88 in. cyclotron. The current of the top and bottom innermost trim coil 1 is unbalanced to study effects of the axial injection displacement. A beam profile monitor images the ion beam bunches, turn by turn. The experimental bunch center of mass position is compared with calculations of the magnetic mirror effect displacement and shows good agreement.

  12. Optical sensors for displacement measurement

    NASA Astrophysics Data System (ADS)

    McGlade, S. M.

    1981-06-01

    A measurement system consists of sensors which are connected to a control center. The use of fiber optics as the communications link has a number of advantages. Two of the most important are immunity from electromagnetic interference and the elimination of the danger of electrical sparking in explosive environments. These advantages are reduced by the necessity to use electrical devices in the sensors. If the sensors were wholly optical then the advantages of fiber optics would apply to the entire system outside the control center. Optical sensors will be difficult to develop. Initially, at least, they are only justified in applications where such methods are becoming essential. One such area is in military aircraft. An optical displacement transducer can be obtained by using the displacement to alter the transmission aperture of a light beam. Attention is also given to strain measurement using two beam interferometry, Fabry-Perot interferometry displacement measurement, and strain induced birefringence.

  13. Dual pressure displacement control system

    SciTech Connect

    Louis, J.E.; Klocke, C.C.

    1988-02-02

    This patent describes a dual pressure servo control system for a variable displacement hydraulic unit having displacement setting means positioned by a hydraulic servo mechanism. The hydraulic unit is provided with main loop lines at least one of which is capable of being subjected to high main loop pressure during operation of the hydraulic unit, a control line including a displacement control valve providing a controlled flow of fluid under pressure to the servo mechanism, and a source of fluid under pressure for the control line comprising a low pressure source connected to the control line through a check valve and high pressure source comprising of a high pressure control line connected to the control line downstream of the check valve. The high pressure control line includes a flow restriction limiting flow to the control line means and generating a significant flow induced pressure drop in the high pressure control line once movement in the servo mechanism is initiated.

  14. Perceived displacement explains wolfpack effect.

    PubMed

    Šimkovic, Matúš; Träuble, Birgit

    2014-01-01

    We investigate the influence of perceived displacement of moving agent-like stimuli on the performance in dynamic interactive tasks. In order to reliably measure perceived displacement we utilize multiple tasks with different task demands. The perceived center of an agent's body is displaced in the direction in which the agent is facing and this perceived displacement is larger than the theoretical position of the center of mass would predict. Furthermore, the displacement in the explicit judgment is dissociated from the displacement obtained by the implicit measures. By manipulating the location of the pivot point, we show that it is not necessary to postulate orientation as an additional cue utilized by perception, as has been suggested by earlier studies. These studies showed that the agent's orientation influences the detection of chasing motion and the detection-related performance in interactive tasks. This influence has been labeled wolfpack effect. In one of the demonstrations of the wolfpack effect participants control a green circle on a display with a computer mouse. It has been shown that participants avoid display areas with agents pointing toward the green circle. Participants do so in favor of areas where the agents point in the direction perpendicular to the circle. We show that this avoidance behavior arises because the agent's pivot point selected by the earlier studies is different from where people locate the center of agent's body. As a consequence, the nominal rotation confounds rotation and translation. We show that the avoidance behavior disappears once the pivot point is set to the center of agent's body. PMID:25566114

  15. Combined correlation estimation of axial displacement in optical coherence elastography: assessment of axial displacement sensitivity performance relative to existing methods

    NASA Astrophysics Data System (ADS)

    Grimwood, A.; Messa, A.; Bamber, J. C.

    2015-03-01

    A combined correlation method is introduced to optical coherence elastography for axial displacement estimation. Its performance is compared with that of amplitude correlation tracking and phase shift estimation. Relative sensitivities to small (sub-micron), and large (pixel-scale) axial displacements are analysed for a Perspex test object and gelatine phantom. The combined correlation method exhibited good overall performance, with a larger dynamic range than phase shift estimation and higher sensitivity than amplitude correlation tracking.

  16. Molecular Dynamics Simulations of Displacement Cascades in Single and Polycrystalline Zirconia

    SciTech Connect

    Du Jincheng

    2009-03-10

    Displacement cascades in zirconia have been studied using classical molecular dynamics simulations. Polycrystalline zirconia with nano-meter grains were created using Voronoi polyhedra construction and studied in comparison with single crystalline zirconia. The results show that displacement cascades with similar kinetic energy generated larger number of displaced atoms in polycrystalline than in the single crystal structure. The fraction of atoms with coordination number change was also higher in polycrystalline zirconia that was explained to be due to the diffusion of oxygen and relaxation at grain boundaries.

  17. Rotor component displacement measurement system

    DOEpatents

    Mercer, Gary D.; Li, Ming C.; Baum, Charles R.

    2003-05-27

    A measuring system for measuring axial displacement of a tube relative to an axially stationary component in a rotating rotor assembly includes at least one displacement sensor adapted to be located normal to a longitudinal axis of the tube; an insulated cable system adapted for passage through the rotor assembly; a rotatable proximitor module located axially beyond the rotor assembly to which the cables are connected; and a telemetry system operatively connected to the proximitor module for sampling signals from the proximitor module and forwarding data to a ground station.

  18. Understanding interferometry for micro-cantilever displacement detection

    PubMed Central

    Nörenberg, Tobias; Temmen, Matthias; Reichling, Michael

    2016-01-01

    Summary Interferometric displacement detection in a cantilever-based non-contact atomic force microscope (NC-AFM) operated in ultra-high vacuum is demonstrated for the Michelson and Fabry–Pérot modes of operation. Each mode is addressed by appropriately adjusting the distance between the fiber end delivering and collecting light and a highly reflective micro-cantilever, both together forming the interferometric cavity. For a precise measurement of the cantilever displacement, the relative positioning of fiber and cantilever is of critical importance. We describe a systematic approach for accurate alignment as well as the implications of deficient fiber–cantilever configurations. In the Fabry–Pérot regime, the displacement noise spectral density strongly decreases with decreasing distance between the fiber-end and the cantilever, yielding a noise floor of 24 fm/Hz0.5 under optimum conditions. PMID:27547601

  19. Understanding interferometry for micro-cantilever displacement detection.

    PubMed

    von Schmidsfeld, Alexander; Nörenberg, Tobias; Temmen, Matthias; Reichling, Michael

    2016-01-01

    Interferometric displacement detection in a cantilever-based non-contact atomic force microscope (NC-AFM) operated in ultra-high vacuum is demonstrated for the Michelson and Fabry-Pérot modes of operation. Each mode is addressed by appropriately adjusting the distance between the fiber end delivering and collecting light and a highly reflective micro-cantilever, both together forming the interferometric cavity. For a precise measurement of the cantilever displacement, the relative positioning of fiber and cantilever is of critical importance. We describe a systematic approach for accurate alignment as well as the implications of deficient fiber-cantilever configurations. In the Fabry-Pérot regime, the displacement noise spectral density strongly decreases with decreasing distance between the fiber-end and the cantilever, yielding a noise floor of 24 fm/Hz(0.5) under optimum conditions. PMID:27547601

  20. Silicon threshold displacement energy determined by photoluminescence in electron-irradiated cubic silicon carbide

    SciTech Connect

    Lefevre, Jeremie; Esnouf, Stephane; Petite, Guillaume; Costantini, Jean-Marc

    2009-01-15

    In view of the potential use of silicon carbide (SiC) in the nuclear industry, it is of major interest to understand point defect formation in this material. This work is a contribution to the determination of the silicon threshold displacement energy in the cubic polytype of SiC using electron irradiations with increasing energies from 275 to 680 keV. The photoluminescence signal of the silicon vacancy was related to the number of displacements per atom in the silicon sublattice. This quantity was calculated taking into account the energy loss and angular dispersion of electrons in the target. A best fit of experimental data was obtained for a displacement cross section using a threshold displacement energy of 25 eV along the [100] lattice direction. We checked the relevance of this result by comparing the experimental concentration of silicon single vacancies measured by electron paramagnetic resonance spectroscopy with the theoretical number of displaced silicon atoms.

  1. 20 CFR 627.230 - Displacement.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Displacement. 627.230 Section 627.230... PROGRAMS UNDER TITLES I, II, AND III OF THE ACT Program Requirements § 627.230 Displacement. (a) No currently employed worker shall be displaced by any participant (including partial displacement such as...

  2. 20 CFR 627.230 - Displacement.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false Displacement. 627.230 Section 627.230... PROGRAMS UNDER TITLES I, II, AND III OF THE ACT Program Requirements § 627.230 Displacement. (a) No currently employed worker shall be displaced by any participant (including partial displacement such as...

  3. 20 CFR 627.230 - Displacement.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Displacement. 627.230 Section 627.230... PROGRAMS UNDER TITLES I, II, AND III OF THE ACT Program Requirements § 627.230 Displacement. (a) No currently employed worker shall be displaced by any participant (including partial displacement such as...

  4. Displacement transducers using magnetostrictive delay line principle in amorphous materials

    NASA Astrophysics Data System (ADS)

    Meydan, T.; Elshebani, M. S. M.

    1992-07-01

    Amorphous materials, due to their large magnetostriction and small anisotropy, can possess large delay-time variations with a low bias field. This principle has been exploited as a displacement transducer. The time delays were achieved by using an external bias field source.

  5. Interaction of displacement cascade with helium bubbles in alpha-iron: Computer simulation

    SciTech Connect

    Pu, Jin; Yang, Li; Gao, Fei; Heinisch, Howard L.; Kurtz, Richard J.; Zu, Xiaotao T.

    2008-09-01

    Molecular dynamics (MD) method has been performed to study the interaction of displacement cascade with He bubbles with two sets of potentials. The results show that the stability of He bubbles depends much on the initial He-vacancy (He/V) ratio and the recoil energy. For an initial He/V ratio of 3, the cascade leads to the increase in the number of vacancies in the He bubble and the decrease in the He/V ratio. For an initial He/V ratio of 0.5, the interaction of a cascade with the He/V bubble results in the decrease in the number of vacancies and the increase in the He/V ratio. For an initial He/V ratio of 1, the stability of the bubbles slightly depends on the primary knock-on atom (PKA) energy. Furthermore, a large number of self-interstitial atom clusters are formed after cascade collision for the He/V ratio of 3, while large vacancy clusters are observed for the He/V ratio of 0.5. However, some differences of defect production and clustering between the two sets of potentials are observed, which may be associated the formation energies of He-V clusters, the binding energies of vacancies and He atoms to the clusters and the probability of subcascade formation.

  6. Retraining Displaced Workers. Policy Brief

    ERIC Educational Resources Information Center

    LaLonde, Robert; Sullivan, Daniel

    2010-01-01

    Robert LaLonde of the University of Chicago and Daniel Sullivan of the Federal Reserve Bank of Chicago suggest that retraining through our nation's community colleges is a way to reduce the skills gaps of at least some of these displaced workers and increase their reemployment earnings. Although workers may still experience significant earnings…

  7. DISPLACEMENT BASED SEISMIC DESIGN METHODS.

    SciTech Connect

    HOFMAYER,C.MILLER,C.WANG,Y.COSTELLO,J.

    2003-07-15

    A research effort was undertaken to determine the need for any changes to USNRC's seismic regulatory practice to reflect the move, in the earthquake engineering community, toward using expected displacement rather than force (or stress) as the basis for assessing design adequacy. The research explored the extent to which displacement based seismic design methods, such as given in FEMA 273, could be useful for reviewing nuclear power stations. Two structures common to nuclear power plants were chosen to compare the results of the analysis models used. The first structure is a four-story frame structure with shear walls providing the primary lateral load system, referred herein as the shear wall model. The second structure is the turbine building of the Diablo Canyon nuclear power plant. The models were analyzed using both displacement based (pushover) analysis and nonlinear dynamic analysis. In addition, for the shear wall model an elastic analysis with ductility factors applied was also performed. The objectives of the work were to compare the results between the analyses, and to develop insights regarding the work that would be needed before the displacement based analysis methodology could be considered applicable to facilities licensed by the NRC. A summary of the research results, which were published in NUREGICR-6719 in July 2001, is presented in this paper.

  8. Special Programming for Displaced Homemakers.

    ERIC Educational Resources Information Center

    Swift, John S.; And Others

    1986-01-01

    Displaced homemakers returning to college need special services. These programs were developed by one university's center for women: Project Succeed, Back to School Workshops, and Special Programs to Build Self-Confidence. These programs were developed to provide on-the-job training while in college, help adults returning to college earn a degree,…

  9. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W.; Hergenrother, Paul M.; Smith, Joseph G.

    1994-01-01

    Soluble polybenzimidazoles (PBI's) synthesized by nucleophilic displacement reaction of di(hydroxyphenyl)-benzimidazole monomers with activated aromatic difluoride compounds in presence of anhydrous potassium carbonate. These polymers exhibit good thermal, thermo-oxidative, and chemical stability, and high mechanical properties. Using benzimidazole monomers, more economical, and new PBI's processed more easily than commercial PBI, without loss of desirable physical properties.

  10. Method for quantitative determination and separation of trace amounts of chemical elements in the presence of large quantities of other elements having the same atomic mass

    DOEpatents

    Miller, C.M.; Nogar, N.S.

    1982-09-02

    Photoionization via autoionizing atomic levels combined with conventional mass spectroscopy provides a technique for quantitative analysis of trace quantities of chemical elements in the presence of much larger amounts of other elements with substantially the same atomic mass. Ytterbium samples smaller than 10 ng have been detected using an ArF* excimer laser which provides the atomic ions for a time-of-flight mass spectrometer. Elemental selectivity of greater than 5:1 with respect to lutetium impurity has been obtained. Autoionization via a single photon process permits greater photon utilization efficiency because of its greater absorption cross section than bound-free transitions, while maintaining sufficient spectroscopic structure to allow significant photoionization selectivity between different atomic species. Separation of atomic species from others of substantially the same atomic mass is also described.

  11. AAO-assisted synthesis of highly ordered, large-scale TiO2 nanowire arrays via sputtering and atomic layer deposition.

    PubMed

    Yao, Zhao; Wang, Cong; Li, Yang; Kim, Nam-Young

    2015-01-01

    Highly ordered nanoporous anodic aluminum oxide (AAO) thin films were fabricated in oxalic acid under a constant voltage via a two-step anodization process. To investigate the high-aspect-ratio (7.5:1) filling process, both sputtering and atomic layer deposition (ALD) were used to form TiO2 nanowires. Field emission scanning electron microscopy and high-resolution transmission electron microscopy images indicated that mushroom-like TiO2 structures were sputtered onto the AAO template surface, and the ALD-coated TiO2 exhibited fine filling results and clear crystal grain boundaries. Large-scale and free-standing TiO2 nanowire arrays were liberated by selectively removing the aluminum substrate and AAO template via a wet etching process with no collapsing or agglomeration after the drying process. ALD-deposited TiO2 nanowire arrays that were 67 nm in diameter and 400 nm high were transferred from the AAO template. The ALD process enabled the rapid, simple synthesis of highly ordered TiO2 nanowire arrays with desired parameters such as diameter, density, and thickness determined using diverse AAO templates. PMID:25897309

  12. AAO-assisted synthesis of highly ordered, large-scale TiO2 nanowire arrays via sputtering and atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Yao, Zhao; Wang, Cong; Li, Yang; Kim, Nam-Young

    2015-04-01

    Highly ordered nanoporous anodic aluminum oxide (AAO) thin films were fabricated in oxalic acid under a constant voltage via a two-step anodization process. To investigate the high-aspect-ratio (7.5:1) filling process, both sputtering and atomic layer deposition (ALD) were used to form TiO2 nanowires. Field emission scanning electron microscopy and high-resolution transmission electron microscopy images indicated that mushroom-like TiO2 structures were sputtered onto the AAO template surface, and the ALD-coated TiO2 exhibited fine filling results and clear crystal grain boundaries. Large-scale and free-standing TiO2 nanowire arrays were liberated by selectively removing the aluminum substrate and AAO template via a wet etching process with no collapsing or agglomeration after the drying process. ALD-deposited TiO2 nanowire arrays that were 67 nm in diameter and 400 nm high were transferred from the AAO template. The ALD process enabled the rapid, simple synthesis of highly ordered TiO2 nanowire arrays with desired parameters such as diameter, density, and thickness determined using diverse AAO templates.

  13. INFLUENCE OF MASS ON DISPLACEMENT THRESHOLD

    SciTech Connect

    Setyawan, Wahyu; Selby, A.; Nandipati, Giridhar; Roche, Kenneth J.; Kurtz, Richard J.; Wirth, Brian D.

    2014-12-30

    Molecular dynamics simulations are performed to investigate the effect of mass on displacement threshold energy in Cr, Mo, Fe and W. For each interatomic potential, the mass of the atoms is varied among those metals for a total of 16 combinations. The average threshold energy over all crystal directions is calculated within the irreducible crystal directions using appropriate weighting factors. The weighting factors account for the different number of equivalent directions among the grid points and the different solid angle coverage of each grid point. The grid points are constructed with a Miller index increment of 1/24 for a total of 325 points. For each direction, 10 simulations each with a different primary-knock-on atom are performed. The results show that for each interatomic potential, the average threshold energy is insensitive to the mass; i.e., the values are the same within the standard error. In the future, the effect of mass on high-energy cascades for a given interatomic potential will be investigated.

  14. Role of W and Mn for reliable 1X nanometer-node ultra-large-scale integration Cu interconnects proved by atom probe tomography

    NASA Astrophysics Data System (ADS)

    Shima, K.; Tu, Y.; Takamizawa, H.; Shimizu, H.; Shimizu, Y.; Momose, T.; Inoue, K.; Nagai, Y.; Shimogaki, Y.

    2014-09-01

    We used atom probe tomography (APT) to study the use of a Cu(Mn) as a seed layer of Cu, and a Co(W) single-layer as reliable Cu diffusion barriers for future interconnects in ultra-large-scale integration. The use of Co(W) layer enhances adhesion of Cu to prevent electromigration and stress-induced voiding failures. The use of Cu(Mn) as seed layer may enhance the diffusion barrier performance of Co(W) by stuffing the Cu diffusion pass with Mn. APT was used to visualize the distribution of W and Mn in three dimensions with sub-nanometer resolution. W was found to segregate at the grain boundaries of Co, which prevents diffusion of Cu via the grain boundaries. Mn was found to diffuse from the Cu(Mn) layer to Co(W) layer and selectively segregate at the Co(W) grain boundaries with W, reinforcing the barrier properties of Co(W) layer. Hence, a Co(W) barrier coupled with a Cu(Mn) seed layer can form a sufficient diffusion barrier with film that is less than 2.0-nm-thick. The diffusion barrier behavior was preserved following a 1-h annealing at 400 °C. The underlayer of the Cu interconnects requires a large adhesion strength with the Cu, as well as low electrical resistivity. The use of Co(W) has previously been shown to satisfy these requirements, and addition of Mn is not expected to deteriorate these properties.

  15. Role of W and Mn for reliable 1X nanometer-node ultra-large-scale integration Cu interconnects proved by atom probe tomography

    SciTech Connect

    Shima, K.; Shimizu, H.; Momose, T.; Shimogaki, Y.; Tu, Y.; Takamizawa, H.; Shimizu, Y.; Inoue, K.; Nagai, Y.

    2014-09-29

    We used atom probe tomography (APT) to study the use of a Cu(Mn) as a seed layer of Cu, and a Co(W) single-layer as reliable Cu diffusion barriers for future interconnects in ultra-large-scale integration. The use of Co(W) layer enhances adhesion of Cu to prevent electromigration and stress-induced voiding failures. The use of Cu(Mn) as seed layer may enhance the diffusion barrier performance of Co(W) by stuffing the Cu diffusion pass with Mn. APT was used to visualize the distribution of W and Mn in three dimensions with sub-nanometer resolution. W was found to segregate at the grain boundaries of Co, which prevents diffusion of Cu via the grain boundaries. Mn was found to diffuse from the Cu(Mn) layer to Co(W) layer and selectively segregate at the Co(W) grain boundaries with W, reinforcing the barrier properties of Co(W) layer. Hence, a Co(W) barrier coupled with a Cu(Mn) seed layer can form a sufficient diffusion barrier with film that is less than 2.0-nm-thick. The diffusion barrier behavior was preserved following a 1-h annealing at 400 °C. The underlayer of the Cu interconnects requires a large adhesion strength with the Cu, as well as low electrical resistivity. The use of Co(W) has previously been shown to satisfy these requirements, and addition of Mn is not expected to deteriorate these properties.

  16. Free displacer and Ringbom displacer for a Malone refrigerator

    SciTech Connect

    Swift, G.W.; Brown, A.O.

    1994-05-01

    Malone refrigeration uses a liquid near its critical point (instead of the customary gas) as the working fluid in a Stirling, Brayton, or similar regenerative or recuperative cycle. Thus far, we have focused on the Stirling cycle, to avoid the difficult construction of the high-pressure-difference counterflow recuperator required for a Brayton machine. Our first Malone refrigerator used liquid propylene (C{sub 3}H{sub 6}) in a double-acting 4-cylinder Stirling configuration. First measurements with a free displacer used in a liquid working fluid are presented. The displacer was operated both in harmonic mode and in Ringbom mode, in liquid carbon dioxide. The results are in reasonable agreement with expectations.

  17. A high-resolution neutron powder diffraction investigation of galena (PbS) between 10 K and 350 K: no evidence for anomalies in the lattice parameters or atomic displacement parameters in galena or altaite (PbTe) at temperatures corresponding to the saturation of cation disorder

    NASA Astrophysics Data System (ADS)

    Knight, K. S.

    2014-09-01

    The temperature dependences of the unit cell parameter and the atomic displacement parameters (adp) for galena (PbS) have been measured using high resolution neutron powder diffraction in the temperature interval 10-350 K. No evidence has been found for the anomalous behaviour recently reported in a total scattering study of galena, in which the temperature variation of both the unit cell and the adp for lead are reported to undergo a dramatic reduction at a temperature of ~250 K. The linear thermal expansion coefficient calculated from the powder diffraction study is found to be in excellent agreement with literature values over the entire temperature interval studied, and approximately 25% greater at room temperature than that determined by analysis of the pair distribution function (pdf) derived from the total scattering data. This discrepancy is shown to be attributable to a linear, temperature-dependent offset from the published temperatures in the total scattering study, and has arisen from the sample temperature being significantly lower than the experimental set point temperature. Applying this correction to the adps of the lead cation removes the anomalous temperature dependence and shows the pdf results are in agreement with the neutron powder diffraction results. Application of the identical temperature offsets to the results of the pdf analysis of data collected on altaite (PbTe) eliminates the anomalous behaviour in the unit cell and the adp for lead, bringing them in line with literature values. Contrary to the conclusions of the pdf analysis, adps for the lead cation in both galena and altaite can be described in terms of Debye-like behaviour and are consistent with the partial phonon density of states.

  18. A high-resolution neutron powder diffraction investigation of galena (PbS) between 10 K and 350 K: no evidence for anomalies in the lattice parameters or atomic displacement parameters in galena or altaite (PbTe) at temperatures corresponding to the saturation of cation disorder.

    PubMed

    Knight, K S

    2014-09-24

    The temperature dependences of the unit cell parameter and the atomic displacement parameters (adp) for galena (PbS) have been measured using high resolution neutron powder diffraction in the temperature interval 10-350 K. No evidence has been found for the anomalous behaviour recently reported in a total scattering study of galena, in which the temperature variation of both the unit cell and the adp for lead are reported to undergo a dramatic reduction at a temperature of ~250 K. The linear thermal expansion coefficient calculated from the powder diffraction study is found to be in excellent agreement with literature values over the entire temperature interval studied, and approximately 25% greater at room temperature than that determined by analysis of the pair distribution function (pdf) derived from the total scattering data. This discrepancy is shown to be attributable to a linear, temperature-dependent offset from the published temperatures in the total scattering study, and has arisen from the sample temperature being significantly lower than the experimental set point temperature. Applying this correction to the adps of the lead cation removes the anomalous temperature dependence and shows the pdf results are in agreement with the neutron powder diffraction results. Application of the identical temperature offsets to the results of the pdf analysis of data collected on altaite (PbTe) eliminates the anomalous behaviour in the unit cell and the adp for lead, bringing them in line with literature values. Contrary to the conclusions of the pdf analysis, adps for the lead cation in both galena and altaite can be described in terms of Debye-like behaviour and are consistent with the partial phonon density of states. PMID:25185952

  19. Displacement damage in silicon carbide irradiated in fission reactors

    NASA Astrophysics Data System (ADS)

    Heinisch, H. L.; Greenwood, L. R.; Weber, W. J.; Williford, R. E.

    2004-05-01

    Calculations are performed for displacement damage in SiC due to irradiation in the neutron environments of various types of nuclear reactors using the best available models and nuclear data. The displacement damage calculations use recently developed damage functions for SiC that are based on extensive molecular dynamics simulations of displacement events. Displacements per atom (DPA) cross sections for SiC have been calculated as a function of neutron energy, and they are presented here in tabular form to facilitate their use as the standard measure of displacement damage for irradiated SiC. DPA cross sections averaged over the neutron energy spectrum are calculated for neutron spectra in the cores of typical commercial reactors and in the test sample irradiation regions of several materials test reactors used in both past and present irradiation testing. Particular attention is focused on a next-generation high-temperature gas-cooled pebble bed reactor, for which the high-temperature properties of silicon carbide fiber-reinforced silicon carbide composites are well suited. Calculated transmutations and activation levels in a pebble bed reactor are compared to those in other reactors.

  20. Some Considerations on Horizontal Displacement and Horizontal Displacement Coefficient B

    NASA Astrophysics Data System (ADS)

    Tajduś, Krzysztof; Tajduś, Antoni

    2015-12-01

    Mining-induced deformations of the ground surface and within the rock mass may pose danger not only for surface constructions but also for underground objects (e.g., tunnels, underground storages, garages), diverse types of pipelines, electric cables, etc. For a proper evaluation of hazard for surface and underground objects, such parameters as horizontal displacement and horizontal deformations, especially their maximum values, are of crucial importance. The paper is an attempt at a critical review of hitherto accomplished studies and state of the art of predicting horizontal displacement u, in particular the coefficient B, whose value allows determination of the value of maximum displacement if the value of maximum slope is known, or the value of maximum deformation if the value of maximum trough slope is recognized. Since the geodesic observations of fully developed subsidence troughs suggest that the value of the coefficient depends on the depth H, radius of main influences range r and properties of overburden rock, in particular the occurrence of sub-eras Paleogene and Neogene layers (old name: Quaternary and Tertiary) with low strength parameters, therefore a formula is provided in the present paper allowing for the estimation of the influence of those factors on the value of coefficient B.

  1. Displacement cascades and defects annealing in tungsten, Part I: Defect database from molecular dynamics simulations

    SciTech Connect

    Setyawan, Wahyu; Nandipati, Giridhar; Roche, Kenneth J.; Heinisch, Howard L.; Wirth, Brian D.; Kurtz, Richard J.

    2015-07-01

    Molecular dynamics simulations have been used to generate a comprehensive database of surviving defects due to displacement cascades in bulk tungsten. Twenty-one data points of primary knock-on atom (PKA) energies ranging from 100 eV (sub-threshold energy) to 100 keV (~780×Ed, where Ed = 128 eV is the average displacement threshold energy) have been completed at 300 K, 1025 K and 2050 K. Within this range of PKA energies, two regimes of power-law energy-dependence of the defect production are observed. A distinct power-law exponent characterizes the number of Frenkel pairs produced within each regime. The two regimes intersect at a transition energy which occurs at approximately 250×Ed. The transition energy also marks the onset of the formation of large self-interstitial atom (SIA) clusters (size 14 or more). The observed defect clustering behavior is asymmetric, with SIA clustering increasing with temperature, while the vacancy clustering decreases. This asymmetry increases with temperature such that at 2050 K (~0.5Tm) practically no large vacancy clusters are formed, meanwhile large SIA clusters appear in all simulations. The implication of such asymmetry on the long-term defect survival and damage accumulation is discussed. In addition, <100> {110} SIA loops are observed to form directly in the highest energy cascades, while vacancy <100> loops are observed to form at the lowest temperature and highest PKA energies, although the appearance of both the vacancy and SIA loops with Burgers vector of <100> type is relatively rare.

  2. Super-radiant super-resolving displacement estimation via multiple photons by the Wang's method

    NASA Astrophysics Data System (ADS)

    Xia, Li-Xin; Abdureyim, Muhammad-Tursun; Liu, Run-Qin; Yu, Sheng-Qing; Guo, Ling; Zhou, Xiang-Ling

    2015-06-01

    In this paper, we propose a super-radiant measurement scheme to achieve Heisenberg limit super-resolving displacement estimation by encoding multiple light momenta into a three-level atomic ensemble with multiple ? photons. And by the Wang's method (Phys. Rev. Lett. 2014, 113, 083601), we use ? coherent pulses to prepare a ?-excitation super-radiant state in a super-position of two timed Dicke states that are ? light momenta apart in the momentum space. The phase difference between these two states induced by a uniform displacement of the atomic ensemble has ? sensitivity. In the end, we introduce two experiments based on Ramsey interferometry in crystal and in ultracold atoms.

  3. Hot-solvent miscible displacement

    SciTech Connect

    Awang, M.; Farouq Ali, S.M.

    1980-01-01

    This work describes an experimental and theoretical investigation of miscible displacement under nonisothermal conditions. The hot miscible floods were performed in an adiabatic glass bead pack, displacing one hydrocarbon by a more viscous hydrocarbon, the latter being at an elevated temperature. As a result, dispersion of both mass and heat took place, and was determined by temperature and concentration measurements. The system was simulated by coupled convective-diffusion and thermal conduction-convection equations. The results of the numerical as well as an approximate analytical solution were compared with the experimentally observed behavior. The numerical and experimental results point to the factors which should be considered in the choice of a solvent for a thermal-miscible type oil recovery process.

  4. Sample displacement batch chromatography of proteins.

    PubMed

    Kotasinska, Marta; Richter, Verena; Kwiatkowski, Marcel; Schlüter, Hartmut

    2014-01-01

    In downstream processing large scale chromatography plays an important role. For its development screening experiments followed by pilot plant chromatography are mandatory steps. Here we describe fast, simple, and inexpensive methods for establishing a preparative chromatography for the separation of complex protein mixtures, based on sample displacement batch chromatography. The methods are demonstrated by anion-exchange chromatography of a human plasma protein fraction (Cohn IV-4), including the screening step and scaling up of the chromatography by a factor of 100. The results of the screening experiments and the preparative chromatography are monitored by SDS-PAGE electrophoresis. In summary we provide a protocol which should be easily adaptable for the chromatographic large scale purification of other proteins, in the laboratory as well as in industry for commercial manufacturing. For the latter these protocols cover the initial piloting steps for establishing a sample batch chromatography based on packed columns rather than batch chromatography. PMID:24648085

  5. Polybenzimidazole via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G. (Inventor)

    1994-01-01

    Di(hydroxyphenyl)benzimidazole monomers were prepared from phenyl-4-hydroxybenzoate and aromatic bis(o-diamine)s. These monomers were used in the synthesis of soluble polybenzimidazoles. The reaction involved the aromatic nucleophilic displacement of various di(hydroxyphenyl)benzimidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds in the presence of an alkali metal base. These polymers exhibited lower glass transition temperatures, improved solubility, and better compression moldability over their commercial counterparts.

  6. Harnack Inequalities and Discrete—Continuous Error Estimates for a Chain of Atoms with Two—Body Interactions

    NASA Astrophysics Data System (ADS)

    Benguria, R.; Dolbeault, J.; Monneau, R.

    2009-01-01

    We consider deformations in ℝ3 of an infinite linear chain of atoms where each atom interacts with all others through a two-body potential. We compute the effect of an external force applied to the chain. At equilibrium, the positions of the particles satisfy an Euler-Lagrange equation. For large classes of potentials, we prove that every solution is well approximated by the solution of a continuous model when applied forces and displacements of the atoms are small. We establish an error estimate between the discrete and the continuous solution based on a Harnack lemma of independent interest. Finally we apply our results to some Lennard-Jones potentials.

  7. Influence of subcascade formation on displacement damage at high PKA energies

    SciTech Connect

    Stoller, R.E.; Greenwood, L.R.

    1997-08-01

    The design of first generation fusion reactors will have to be rely on radiation effects data obtained from experiments conducted in fission reactors. Two issues must be addressed to use this data with confidence. The first is differences in the neutron energy spectrum, and the second is differences in nuclear transmutation rates. Differences in the neutron energy spectra are reflected in the energy spectra of the primary knockon atoms (PKA). The issue of PKA energy effects has been addressed through the use of displacement cascade simulations using the method of molecular dynamics (MD). Although MD simulations can provide a detailed picture of the formation and evolution of displacement cascades, they impose a substantial computational burden. However, recent advances in computing equipment permit the simulation of high energy displacement events involving more than one-million atoms; the results presented here encompass MD cascade simulation energies from near the displacement threshold to as high as 40 keV. Two parameters have been extracted from the MD simulations: the number of point defects that remain after the displacement event is completed and the fraction of the surviving interstitials that are contained in clusters. The MD values have been normalized to the number of atomic displacements calculated with the secondary displacement model by Norgett, Robinson, and Torrens (NRT).

  8. Additional longitudinal displacement for contaminant dispersion in wetland flow

    NASA Astrophysics Data System (ADS)

    Fu, Xudong; Gao, Ran; Wu, Zi

    2016-01-01

    When there is a sudden and uniform release of contaminant over the depth of wetland, the centroid of resulted solute cloud will travel downstream at the cross-sectional mean velocity of the flow. However, if the initial release is not uniform, there will be an additional longitudinal displacement of the centroid, which is important for predicting the concentration distribution but cannot be revealed by the classical one-dimensional Taylor dispersion model. For the most typical case of an initial point source release at the free-water-surface of the wetland, an idealized case modeling accidental leakage of toxic chemicals in waters, in the present paper we analytically deduce the longitudinal displacement by the method of concentration moment. The result is then incorporated in the analytical solutions of concentration distribution, which are further verified by our numerical simulations. The effects of the longitudinal displacement on the concentration distribution are analyzed in detail. It is shown that without considering the displacement, for vertical planes close to the edges of the contaminant cloud, the analytical solution can over- or under-estimate the vertical distribution of concentration for over 20% of the maximum concentration in the plane even at a large dimensionless time of t∗ = 5 . The longitudinal displacement is shown to decrease with the increase of the important damping factor α, which characterizes the effects of vegetation in wetlands. A simple application is given at the end of this paper to illustrate the evolution of the additional longitudinal displacement.

  9. A wireless laser displacement sensor node for structural health monitoring.

    PubMed

    Park, Hyo Seon; Kim, Jong Moon; Choi, Se Woon; Kim, Yousok

    2013-01-01

    This study describes a wireless laser displacement sensor node that measures displacement as a representative damage index for structural health monitoring (SHM). The proposed measurement system consists of a laser displacement sensor (LDS) and a customized wireless sensor node. Wireless communication is enabled by a sensor node that consists of a sensor module, a code division multiple access (CDMA) communication module, a processor, and a power module. An LDS with a long measurement distance is chosen to increase field applicability. For a wireless sensor node driven by a battery, we use a power control module with a low-power processor, which facilitates switching between the sleep and active modes, thus maximizing the power consumption efficiency during non-measurement and non-transfer periods. The CDMA mode is also used to overcome the limitation of communication distance, which is a challenge for wireless sensor networks and wireless communication. To evaluate the reliability and field applicability of the proposed wireless displacement measurement system, the system is tested onsite to obtain the required vertical displacement measurements during the construction of mega-trusses and an edge truss, which are the primary structural members in a large-scale irregular building currently under construction. The measurement values confirm the validity of the proposed wireless displacement measurement system and its potential for use in safety evaluations of structural elements. PMID:24084114

  10. A Wireless Laser Displacement Sensor Node for Structural Health Monitoring

    PubMed Central

    Park, Hyo Seon; Kim, Jong Moon; Choi, Se Woon; Kim, Yousok

    2013-01-01

    This study describes a wireless laser displacement sensor node that measures displacement as a representative damage index for structural health monitoring (SHM). The proposed measurement system consists of a laser displacement sensor (LDS) and a customized wireless sensor node. Wireless communication is enabled by a sensor node that consists of a sensor module, a code division multiple access (CDMA) communication module, a processor, and a power module. An LDS with a long measurement distance is chosen to increase field applicability. For a wireless sensor node driven by a battery, we use a power control module with a low-power processor, which facilitates switching between the sleep and active modes, thus maximizing the power consumption efficiency during non-measurement and non-transfer periods. The CDMA mode is also used to overcome the limitation of communication distance, which is a challenge for wireless sensor networks and wireless communication. To evaluate the reliability and field applicability of the proposed wireless displacement measurement system, the system is tested onsite to obtain the required vertical displacement measurements during the construction of mega-trusses and an edge truss, which are the primary structural members in a large-scale irregular building currently under construction. The measurement values confirm the validity of the proposed wireless displacement measurement system and its potential for use in safety evaluations of structural elements. PMID:24084114

  11. A DISPLACED SUPERMASSIVE BLACK HOLE IN M87

    SciTech Connect

    Batcheldor, D.; Perlman, E. S.; Robinson, A.; Merritt, D.; Axon, D. J.

    2010-07-01

    Isophotal analysis of M87, using data from the Advanced Camera for Surveys, reveals a projected displacement of 6.8 {+-} 0.8 pc ({approx}0.''1) between the nuclear point source (presumed to be the location of the supermassive black hole, SMBH) and the photo-center of the galaxy. The displacement is along a position angle of 307{sup 0} {+-} 17{sup 0} and is consistent with the jet axis. This suggests the active SMBH in M87 does not currently reside at the galaxy center of mass, but is displaced in the counter-jet direction. Possible explanations for the displacement include orbital motion of an SMBH binary, gravitational perturbations due to massive objects (e.g., globular clusters), acceleration by an asymmetric or intrinsically one-sided jet, and gravitational recoil resulting from the coalescence of an SMBH binary. The displacement direction favors the latter two mechanisms. However, jet asymmetry is only viable, at the observed accretion rate, for a jet age of >0.1 Gyr and if the galaxy restoring force is negligible. This could be the case in the low-density core of M87. A moderate recoil {approx}1 Myr ago might explain the disturbed nature of the nuclear gas disk, could be aligned with the jet axis, and can produce the observed offset. Alternatively, the displacement could be due to residual oscillations resulting from a large recoil that occurred in the aftermath of a major merger {<=}1 Gyr ago.

  12. Software for determining the true displacement of faults

    NASA Astrophysics Data System (ADS)

    Nieto-Fuentes, R.; Nieto-Samaniego, Á. F.; Xu, S.-S.; Alaniz-Álvarez, S. A.

    2014-03-01

    One of the most important parameters of faults is the true (or net) displacement, which is measured by restoring two originally adjacent points, called “piercing points”, to their original positions. This measurement is not typically applicable because it is rare to observe piercing points in natural outcrops. Much more common is the measurement of the apparent displacement of a marker. Methods to calculate the true displacement of faults using descriptive geometry, trigonometry or vector algebra are common in the literature, and most of them solve a specific situation from a large amount of possible combinations of the fault parameters. True displacements are not routinely calculated because it is a tedious and tiring task, despite their importance and the relatively simple methodology. We believe that the solution is to develop software capable of performing this work. In a previous publication, our research group proposed a method to calculate the true displacement of faults by solving most combinations of fault parameters using simple trigonometric equations. The purpose of this contribution is to present a computer program for calculating the true displacement of faults. The input data are the dip of the fault; the pitch angles of the markers, slickenlines and observation lines; and the marker separation. To prevent the common difficulties involved in switching between operative systems, the software is developed using the Java programing language. The computer program could be used as a tool in education and will also be useful for the calculation of the true fault displacement in geological and engineering works. The application resolves the cases with known direction of net slip, which commonly is assumed parallel to the slickenlines. This assumption is not always valid and must be used with caution, because the slickenlines are formed during a step of the incremental displacement on the fault surface, whereas the net slip is related to the finite slip.

  13. Meridional displacement of the Antarctic Circumpolar Current.

    PubMed

    Gille, Sarah T

    2014-07-13

    Observed long-term warming trends in the Southern Ocean have been interpreted as a sign of increased poleward eddy heat transport or of a poleward displacement of the entire Antarctic Circumpolar Current (ACC) frontal system. The two-decade-long record from satellite altimetry is an important source of information for evaluating the mechanisms governing these trends. While several recent studies have used sea surface height contours to index ACC frontal displacements, here altimeter data are instead used to track the latitude of mean ACC transport. Altimetric height contours indicate a poleward trend, regardless of whether they are associated with ACC fronts. The zonally averaged transport latitude index shows no long-term trend, implying that ACC meridional shifts determined from sea surface height might be associated with large-scale changes in sea surface height more than with localized shifts in frontal positions. The transport latitude index is weakly sensitive to the Southern Annular Mode, but is uncorrelated with El Niño/Southern Oscillation. PMID:24891396

  14. Meridional displacement of the Antarctic Circumpolar Current

    PubMed Central

    Gille, Sarah T.

    2014-01-01

    Observed long-term warming trends in the Southern Ocean have been interpreted as a sign of increased poleward eddy heat transport or of a poleward displacement of the entire Antarctic Circumpolar Current (ACC) frontal system. The two-decade-long record from satellite altimetry is an important source of information for evaluating the mechanisms governing these trends. While several recent studies have used sea surface height contours to index ACC frontal displacements, here altimeter data are instead used to track the latitude of mean ACC transport. Altimetric height contours indicate a poleward trend, regardless of whether they are associated with ACC fronts. The zonally averaged transport latitude index shows no long-term trend, implying that ACC meridional shifts determined from sea surface height might be associated with large-scale changes in sea surface height more than with localized shifts in frontal positions. The transport latitude index is weakly sensitive to the Southern Annular Mode, but is uncorrelated with El Niño/Southern Oscillation. PMID:24891396

  15. New method of evaluation for interatomic interaction potential in LEIS with large-angle scattering using the two-atom scattering model

    NASA Astrophysics Data System (ADS)

    Takeuchi, Wataru; Matsuda, Naoki

    2008-03-01

    The interaction potential between an incident ion and a target atom in impact-collision ion scattering spectroscopy (ICISS), which is a specialization of low energy ion scattering (LEIS) and its variants, i.e. ICISS with detection of neutrals (NICISS), coaxial ICISS (CAICISS) and impact-collision atom scattering spectroscopy with detection of neutrals (NICASS), has been evaluated by the new method using the dependence of the total scattering angle on the impact parameter for the first collision in the numerical calculations based on the two-atom scattering model (TWASM). From the comparison of determined values of scaling factor for the Firsov screening length by three-dimensional computer simulations with calculated ones by TWASM, it became obviously that the interatomic potentials for the various combinations of an incident ion and a target atom in LEIS are suitably given by the Moliere potential with the reduced Firsov screening length employing the scaling factor obtained in TWASM calculations.

  16. Molecular dynamics simulations of displacement cascades in GaAs.

    SciTech Connect

    Foiles, Stephen Martin

    2010-04-01

    The quantification of the production of primary defects via displacement cascades is an important ingredient in the prediction of the influence of radiation on the performance of electronic components in radiation environments. Molecular dynamics simulations of displacement cascades are performed for GaAs The interatomic interactions are described using a recently proposed Bond Order Potential, and a simple model of electronic stopping is incorporated. The production of point defects is quantified as a function of recoil energy and recoil species. Correlations in the point defects are examined. There are a large number of anti-site defects nearest-neighbor pairs as well as di-vacancies and larger order vacancy clusters. Radiation damage and ion implantation in materials have been studied via molecular dynamics for many years. A significant challenge in these simulations is the detailed identification and quantification of the primary defect production. For the present case of a compound semiconductor, GaAs, there are a larger number of possible point defects compared to elemental materials; two types of vacancies, two types of interstitials and antisite defects. This is further complicated by the fact that, in addition to the formation of point defects, amorphous zones may also be created. The goal of the current work is to quantify the production of primary defects in GaAs due to radiation exposures. This information will be used as part of an effort to predict the influence of radiation environments on the performance of electronic components and circuits. The data provide the initial state for continuum-level analysis of the temporal evolution of defect populations. For this initial state, it is important to know both the number of the various point defects that may be produced as well as the initial spatial correlations between the primary defects. The molecular dynamics simulations employ a recently developed Bond Order Potential (BOP) for GaAs. The analysis

  17. Advances in Charge Displacement Analysis.

    PubMed

    Bistoni, Giovanni; Belpassi, Leonardo; Tarantelli, Francesco

    2016-03-01

    We define new general density-based descriptors for the quantification of charge transfer and polarization effects associated with the interaction between two fragments and the formation of a chemical bond. Our aim is to provide a simple yet accurate picture of a chemical interaction by condensing the information on the charge rearrangement accompanying it into a few chemically meaningful parameters. These charge displacement (CD) parameters quantify the total charge displaced upon bond formation and decompose it into a charge transfer component between the fragments and charge rearrangements taking place within the fragments. We then show how the new parameters can be easily calculated using the well-known CD function, which describes the charge flow along a chosen axis accompanying the formation of a bond. The approach presented here can be useful in a wide variety of contexts, ranging from weak interactions to electronic excitations to coordination chemistry. In particular, we discuss here how the scheme can be used for the characterization of the donation and back-donation components of metal-ligand bonds, in combination with the natural orbitals for chemical valence (NOCV) theory. In doing so, we discuss the interesting relationship between the proposed parameters and the corresponding NOCV eigenvalues, commonly used as a measure of the electron charge displacement associated with a given bonding contribution. As a prototype case study, we investigate the bond between a N-heterocyclic carbene and different metallic fragments. Finally, we show that our approach can be used in combination with the energy decomposition of the extended transition state method, providing an estimate of both charge transfer and polarization contributions to the interaction energy. PMID:26824715

  18. Displacement Compensation of Temperature Probe Data

    NASA Technical Reports Server (NTRS)

    Welch, Christopher S.; Hubert, James A.; Barber, Patrick G.

    1996-01-01

    Analysis of temperature data from a probe in a vertical Bridgman furnace growing germanium crystals revealed a displacement of the temperature profile due to conduction error. A theoretical analysis shows that the displacement compensation is independent of local temperature gradient. A displacement compensation value should become a standard characteristic of temperature probes used for temperature profile measurements.

  19. 40 CFR 205.153 - Engine displacement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Engine displacement. 205.153 Section... TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the nearest whole cubic...

  20. 40 CFR 205.153 - Engine displacement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Engine displacement. 205.153 Section... TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the nearest whole cubic...

  1. 40 CFR 205.153 - Engine displacement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Engine displacement. 205.153 Section... TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the nearest whole cubic...

  2. 40 CFR 205.153 - Engine displacement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Engine displacement. 205.153 Section... TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the nearest whole cubic...

  3. Technology and Structural Unemployment: Reemploying Displaced Adults.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. Office of Technology Assessment.

    This report concentrates on problems of displaced blue-collar and nonprofessional white-collar workers. Chapter 1 is a summary. Chapter 2 discusses policy issues and options focused on helping people prepare for worklife changes and helping workers to cope if displacement occurs. A definition and description of worker displacement are offered in…

  4. 40 CFR 205.153 - Engine displacement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Engine displacement. 205.153 Section... TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the nearest whole cubic...

  5. Displacement current and surface flashover

    NASA Astrophysics Data System (ADS)

    Harris, J. R.; Caporaso, G. J.; Blackfield, D.; Chen, Y.-J.

    2007-09-01

    High-voltage vacuum insulator failure is generally due to surface flashover rather than insulator bulk breakdown. Vacuum surface flashover is widely believed to be initiated by a secondary electron emission avalanche along the vacuum-insulator interface. This process requires a physical mechanism to cause secondary electrons emitted from the insulator surface to return to that surface. Here, it is shown that when an insulator is subjected to a fast high-voltage pulse, the magnetic field due to displacement current through the insulator can provide this mechanism. This indicates the importance of the voltage pulse shape, especially the rise time, in the flashover initiation process.

  6. Minimization of Displacement Estimation Bias due to High Amplitude Reflections using Envelope-Weighted Normalization

    PubMed Central

    Menon, Manoj; Langdon, Jonathan; McAleavey, Stephen

    2015-01-01

    In elastography, displacement estimation is often performed using cross-correlation based techniques, assuming fully-developed, homogeneous speckle. In the presence of a local, large variation in echo amplitude, such as a reflection from a vessel wall, this assumption does not hold true, resulting in a biased displacement estimate. Normalizing the echo by its envelope before displacement estimation reduces this effect at the cost of larger jitter errors. An algorithm is proposed to reduce amplitude-dependent bias in displacement estimates while avoiding a large increase in the jitter error magnitude. The algorithm involves “Envelope-Weighted Normalization” (EWN) of echo data before displacement estimation. A parametric analysis was conducted to find the optimum parameters with which this technique could be implemented. The EWN technique was found to significantly reduce the RMS error of the displacement estimates showing the greatest improvements when utilizing longer window lengths and higher ultrasonic frequencies. PMID:20687275

  7. Defect-Enhanced Charge Transfer by Ion-Solid Interactions in SiC using Large-Scale Ab Initio Molecular Dynamics Simulations

    SciTech Connect

    Gao, Fei; Xiao, H. Y.; Zu, Xiaotao T.; Posselt, Matthias; Weber, William J.

    2009-07-10

    Large-scale ab initio molecular dynamics simulations of ion-solid interactions in SiC reveal that significant charge-transfer occurs between atoms and defects can enhance charge transfer to surrounding atoms. The results demonstrate that charge transfer to and from recoiling atoms can alter the energy barriers and dynamics for stable defect formation. The present simulations illustrate in detail the dynamic processes for charged defect formation. The averaged values of displacement threshold energies along four main crystallographic directions are smaller than those determined by empirical potentials due to charge transfer effects on recoil atoms.

  8. Defect-Enhanced Charge Transfer by Ion-Solid Interactions in SiC using Large-Scale Ab Initio Molecular Dynamics Simulations

    SciTech Connect

    Gao Fei; Weber, William J.; Xiao Haiyan; Zu Xiaotao; Posselt, Matthias

    2009-07-10

    Large-scale ab initio molecular dynamics simulations of ion-solid interactions in SiC reveal that significant charge transfer occurs between atoms, and defects can enhance charge transfer to surrounding atoms. The results demonstrate that charge transfer to and from recoiling atoms can alter the energy barriers and dynamics for stable defect formation. The present simulations illustrate in detail the dynamic processes for charged defect formation. The averaged values of displacement threshold energies along four main crystallographic directions are smaller than those determined by empirical potentials due to charge-transfer effects on recoil atoms.

  9. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, J.

    1995-05-30

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 29 figs.

  10. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, J.

    1999-04-06

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 23 figs.

  11. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, John

    1999-01-01

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.

  12. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, John

    1995-01-01

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.

  13. Genetics of bovine abomasal displacement.

    PubMed

    Zerbin, Ina; Lehner, Stefanie; Distl, Ottmar

    2015-04-01

    Displacement of the abomasum (DA) is a common inherited condition in Holstein cows. This article reviews the genetics of DA including risk factors, genetic parameters and molecular genetic results. Breeds other than Holsteins affected by DA include Guernseys, Jerseys, Brown Swiss, Ayrshires and Simmental-Red Holsteins. In most DA cases, left displacements of the abomasum (LDA) are seen. Lactation incidence rates are higher for DA in first lactation Holsteins compared to later lactations. For Holstein cows, heritability estimates for DA are between 0.03 and 0.53. Genetic correlation estimates among DA and milk production traits range from positive to negative. Genome-wide significant genomic regions associated with LDA are located on bovine chromosomes (BTA) 1, 3, 11, 20 and 23. Motilin-associated single nucleotide polymorphisms on BTA23 exhibit a functional relationship with LDA. Pathways for deposition of calcium, insulin-dependent diabetes mellitus and synaptic transmission are significantly related to LDA in Holsteins. Deciphering the DA-associated genomic regions and genes may be an important step in the quest to understand the underlying disease-causing mechanisms and in unravelling mutations with a causal relationship to DA. PMID:25840863

  14. On the calculation of line strengths, oscillator strengths and lifetimes for very large principal quantum numbers in hydrogenic atoms and ions by the McLean-Watson formula

    NASA Astrophysics Data System (ADS)

    Hey, J. D.

    2014-08-01

    As a sequel to an earlier study (Hey 2009 J. Phys. B: At. Mol. Opt. Phys. 42 125701), we consider further the application of the line strength formula derived by Watson (2006 J. Phys. B: At. Mol. Opt. Phys. 39 L291) to transitions arising from states of very high principal quantum number in hydrogenic atoms and ions (Rydberg-Rydberg transitions, n > 1000). It is shown how apparent difficulties associated with the use of recurrence relations, derived (Hey 2006 J. Phys. B: At. Mol. Opt. Phys. 39 2641) by the ladder operator technique of Infeld and Hull (1951 Rev. Mod. Phys. 23 21), may be eliminated by a very simple numerical device, whereby this method may readily be applied up to n ≈ 10 000. Beyond this range, programming of the method may entail greater care and complexity. The use of the numerically efficient McLean-Watson formula for such cases is again illustrated by the determination of radiative lifetimes and comparison of present results with those from an asymptotic formula. The question of the influence on the results of the omission or inclusion of fine structure is considered by comparison with calculations based on the standard Condon-Shortley line strength formula. Interest in this work on the radial matrix elements for large n and n‧ is related to measurements of radio recombination lines from tenuous space plasmas, e.g. Stepkin et al (2007 Mon. Not. R. Astron. Soc. 374 852), Bell et al (2011 Astrophys. Space Sci. 333 377), to the calculation of electron impact broadening parameters for such spectra (Watson 2006 J. Phys. B: At. Mol. Opt. Phys. 39 1889) and comparison with other theoretical methods (Peach 2014 Adv. Space Res. in press), to the modelling of physical processes in H II regions (Roshi et al 2012 Astrophys. J. 749 49), and the evaluation bound-bound transitions from states of high n during primordial cosmological recombination (Grin and Hirata 2010 Phys. Rev. D 81 083005, Ali-Haïmoud and Hirata 2010 Phys. Rev. D 82 063521, Ali

  15. Ultrasensitive detection of force and displacement using trapped ions.

    PubMed

    Biercuk, Michael J; Uys, Hermann; Britton, Joe W; VanDevender, Aaron P; Bollinger, John J

    2010-09-01

    The ability to detect extremely small forces and nanoscale displacements is vital for disciplines such as precision spin-resonance imaging, microscopy, and tests of fundamental physical phenomena. Current force-detection sensitivity limits have surpassed 1 aN Hz(-1/2) (refs 6,7) through coupling of nanomechanical resonators to a variety of physical readout systems. Here, we demonstrate that crystals of trapped atomic ions behave as nanoscale mechanical oscillators and may form the core of exquisitely sensitive force and displacement detectors. We report the detection of forces with a sensitivity of 390 +/- 150 yN Hz(-1/2), which is more than three orders of magnitude better than existing reports using nanofabricated devices(7), and discriminate ion displacements of approximately 18 nm. Our technique is based on the excitation of tunable normal motional modes in an ion trap and detection through phase-coherent Doppler velocimetry, and should ultimately allow force detection with a sensitivity better than 1 yN Hz(-1/2) (ref. 16). Trapped-ion-based sensors could enable scientists to explore new regimes in materials science where augmented force, field and displacement sensitivity may be traded against reduced spatial resolution. PMID:20729835

  16. Ultrasensitive detection of force and displacement using trapped ions

    NASA Astrophysics Data System (ADS)

    Biercuk, Michael J.; Uys, Hermann; Britton, Joe W.; Vandevender, Aaron P.; Bollinger, John J.

    2010-09-01

    The ability to detect extremely small forces and nanoscale displacements is vital for disciplines such as precision spin-resonance imaging, microscopy, and tests of fundamental physical phenomena. Current force-detection sensitivity limits have surpassed 1 aN Hz-1/2 (refs 6,7) through coupling of nanomechanical resonators to a variety of physical readout systems. Here, we demonstrate that crystals of trapped atomic ions behave as nanoscale mechanical oscillators and may form the core of exquisitely sensitive force and displacement detectors. We report the detection of forces with a sensitivity of 390 +/- 150 yN Hz-1/2, which is more than three orders of magnitude better than existing reports using nanofabricated devices7, and discriminate ion displacements of ~18 nm. Our technique is based on the excitation of tunable normal motional modes in an ion trap and detection through phase-coherent Doppler velocimetry, and should ultimately allow force detection with a sensitivity better than 1 yN Hz-1/2 (ref. 16). Trapped-ion-based sensors could enable scientists to explore new regimes in materials science where augmented force, field and displacement sensitivity may be traded against reduced spatial resolution.

  17. Displacement of squeezed propagating microwave states

    NASA Astrophysics Data System (ADS)

    Fedorov, Kirill G.; Zhong, Ling; Pogorzalek, Stefan; Eder, Peter; Fischer, Michael; Goetz, Jan; Wulschner, Friedrich; Xie, Edwar; Menzel, Edwin; Deppe, Frank; Marx, Achim; Gross, Rudolf

    Displacement of propagating squeezed states is a fundamental operation for quantum communications. It can be applied to fundamental studies of macroscopic quantum coherence and has an important role in quantum teleportation protocols with propagating microwaves. We generate propagating squeezed states using a Josephson parametric amplifier and implement displacement using a cryogenic directional coupler. We study single- and two-mode displacement regimes. For the single-mode displacement we find that the squeezing level of the displaced squeezed state does not depend on the displacement amplitude. Also, we observe that quantum entanglement between two spatially separated channels stays constant across 4 orders of displacement power. We acknowledge support by the German Research Foundation through SFB 631 and FE 1564/1-1, the EU project PROMISCE, and Elite Network of Bavaria through the program ExQM.

  18. Atomic-Resolution STEM Imaging of Graphene at Low Voltage of 30 kV with Resolution Enhancement by Using Large Convergence Angle

    NASA Astrophysics Data System (ADS)

    Sawada, H.; Sasaki, T.; Hosokawa, F.; Suenaga, K.

    2015-04-01

    Atomic resolution at a low accelerating voltage with aberration correction is required to reduce the electron irradiation damage in scanning transmission electron microscopy imaging. However, the reduction in resolution caused by the diffraction limit becomes severe with increasing electron wavelength at low accelerating voltages. The developed aberration corrector can compensate for higher-order aberration in scanning transmission electron microscopy to expand the uniform phase angle. The resolution for imaging graphene at 30 kV is evaluated by changing the convergence angle for a probe-forming system with a higher-order aberration corrector. A single-carbon atom on graphene is successfully imaged at atomic resolution with a cold-field emission gun by dark-field imaging at an accelerating voltage of 30 kV.

  19. A Theoretical Model to Predict Both Horizontal Displacement and Vertical Displacement for Electromagnetic Induction-Based Deep Displacement Sensors

    PubMed Central

    Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

    2012-01-01

    Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors’ mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors’ monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency. PMID:22368467

  20. Atomic-orbital close-coupling calculations for collisions involving fusion relevant highly charged impurity ions using very large basis sets

    SciTech Connect

    Igenbergs, Katharina; Wallerberger, Markus; Schweinzer, Josef; Aumayr, Friedrich

    2012-05-25

    The atomic-orbital close-coupling formalism is a well-known method for the semiclassical treatment of ion-atom collisions. Cross sections for these kinds of collisions are mainly needed in the analysis of certain spectroscopic data from nuclear fusion experiments as well as astrophysical data. We shall outline how the computational implementation can be improved in such a way that collisions involving heavy, highly charged impurity ions, such as Ar{sup 18+} can be treated. Furthermore we show and discuss exemplary results.

  1. Study of the fragmentation of a displacement cascade in subcascades within the Binary Collision Approximation framework

    SciTech Connect

    Luneville, Laurence; Simone, David; Weber, William J

    2011-01-01

    When a material is subjected to irradiation, many primary defects are cre- ated at the atomic level by sequences of ballistic collision events to form highly disordered regions defined as displacement cascades. The long term evolution of materials under irradiation is dictated by the number and the spatial distribution of the surviving defects in the displacement cascade. The peculiar power law shape of collision cross sections is responsible for the frag- mentation of a displacement cascade into smaller subcascades. However, it remains difficult to define a subcascade. Within the fractal geometry frame- work, we demonstrate in this work that the set of atomic trajectories in a displacement cascade exhibit a fractal behavior. From this analysis, we present a new criterion to describe the fragmentation of a displacement cas- cade and to calculate the distribution and the number of defects from this fragmentation. Such an analysis provides the natural framework to estimate the number of defects created in a displacement cascade to integrate with results of MD simulations. From this defiintion of the fragmentation of a displacement cascade, this work gives some new insights to describe both the primary defects produced in a material under irradiation and then to compare different irradiations performed with different particles.

  2. Non-contact displacement estimation using Doppler radar.

    PubMed

    Gao, Xiaomeng; Singh, Aditya; Yavari, Ehsan; Lubecke, Victor; Boric-Lubecke, Olga

    2012-01-01

    Non-contact Doppler radar has been used extensively for detection of physiological motion. Most of the results published to date have been focused on estimation of the physiological rates, such as respiratory rate and heart rate, with CW and modulated waveforms in various settings. Accurate assessment of chest displacement may take this type of monitoring to the new level, by enabling the estimation of associated cardiopulmonary volumes, and possibly pulse pressure. To obtain absolute chest displacement with highest precision, full nonlinear phase demodulation of the quadrature radar outputs must be performed. The accuracy of this type of demodulation is limited by the drifting received RF power, varying dc offset, and channel quadrature imbalance. In this paper we demonstrate that if relatively large motion is used to calibrate the system, smaller motion displacement may be acquired with the accuracy on the order of 30 µm. PMID:23366212

  3. Displacement Based Seismic Design Criteria

    SciTech Connect

    Costello, J.F.; Hofmayer, C.; Park, Y.J.

    1999-03-29

    The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.

  4. DISPLACEMENT BASED SEISMIC DESIGN CRITERIA

    SciTech Connect

    HOFMAYER,C.H.

    1999-03-29

    The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.

  5. Displaced electrode process for welding

    DOEpatents

    Heichel, L.J.

    1975-08-26

    A method is described for the butt-welding of a relatively heavy mass to a relatively small mass such as a thin-wall tube. In butt-welding heat is normally applied at the joint between the two pieces which are butt-welded together. The application of heat at the joint results in overheating the tube which causes thinning of the tube walls and porosity in the tube material. This is eliminated by displacing the welding electrode away from the seam toward the heavier mass so that heat is applied to the heavy mass and not at the butt seam. Examples of the parameters used in welding fuel rods are given. The cladding and end plugs were made of Zircalloy. The electrode used was of 2 percent thoriated tungsten. (auth)

  6. Variable delivery, fixed displacement pump

    SciTech Connect

    Sommars, Mark F.

    2001-01-01

    A variable delivery, fixed displacement pump comprises a plurality of pistons reciprocated within corresponding cylinders in a cylinder block. The pistons are reciprocated by rotation of a fixed angle swash plate connected to the pistons. The pistons and cylinders cooperate to define a plurality of fluid compression chambers each have a delivery outlet. A vent port is provided from each fluid compression chamber to vent fluid therefrom during at least a portion of the reciprocal stroke of the piston. Each piston and cylinder combination cooperates to close the associated vent port during another portion of the reciprocal stroke so that fluid is then pumped through the associated delivery outlet. The delivery rate of the pump is varied by adjusting the axial position of the swash plate relative to the cylinder block, which varies the duration of the piston stroke during which the vent port is closed.

  7. An Ion Displacement Membrane Model

    PubMed Central

    Hladky, Stephen B.; Harris, Joseph D.

    1967-01-01

    The usual assumption in treating the diffusion of ions in an electric field has been that the movement of each ion is independent of the movement of the others. The resulting equation for diffusion by a succession of spontaneous jumps has been well stated by Parlin and Eyring. This paper will consider one simple case in which a different assumption is reasonable. Diffusion of monovalent positive ions is considered as a series of jumps from one fixed negative site to another. The sites are assumed to be full (electrical neutrality). Interaction occurs by the displacement of one ion by another. An ion leaves a site if and only if another ion, not necessarily of the same species, attempts to occupy the same site. Flux ratios and net fluxes are given as functions of the electrical potential, concentration ratios, and number of sites encountered in crossing the membrane. Quantitative comparisons with observations of Hodgkin and Keynes are presented. PMID:6048876

  8. Polybenzimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1995-01-01

    Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl) benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl) benzimidazoles are synthesizedby reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  9. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergerrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1997-01-01

    Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenylbenzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl)benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl)benzimidazoles are synthesized by reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  10. Displaceable Gear Torque Controlled Driver

    NASA Technical Reports Server (NTRS)

    Cook, Joseph S., Jr. (Inventor)

    1997-01-01

    Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

  11. Secondary tasks impair adaptation to step and gradual visual displacements

    PubMed Central

    Galea, J.M.; Sami, S.; Albert, N.B.; Miall, R.C.

    2016-01-01

    Performing two competing tasks can result in dividing cognitive resources between the tasks and impaired motor adaptation. In previous work we have reported impaired learning when participants had to switch from one visual displacement adaptation task to another. Here we examined whether or not a secondary task had a similar effect on adaptation to a visual displacement . The resource dividing task involved simultaneously adapting to a step visual displacement whilst vocally shadowing an auditory stimulus . The switching task required participants to adapt to opposing visual displacements in an alternating manner with the left and right hands. We found that both manipulations had a detrimental effect on adaptation rate. We then integrated these tasks and found the combination caused a greater decrease in adaptation rate than either manipulation in isolation. Experiment 2 showed that adaptation to a gradually imposed visual displacement was influenced in a similar manner to step adaptation. Therefore although gradual adaptation involves minimal awareness it still can be disrupted by a cognitively demanding secondary task. We propose that awareness and cognitive resource can be regarded as qualitatively different but that awareness may be a marker of the amount of resource required. For example, large errors are both noticed and require substantial cognitive resource to connect. However a lack of awareness does not mean an adaptation task will be resistant to interference from a resource consuming secondary task. PMID:20101396

  12. The brain uses extrasomatic information to estimate limb displacement

    PubMed Central

    Terekhov, Alexander V.; Hayward, Vincent

    2015-01-01

    A fundamental problem faced by the brain is to estimate whether a touched object is rigidly attached to a ground reference or is movable. A simple solution to this problem would be for the brain to test whether pushing on the object with a limb is accompanied by limb displacement. The mere act of pushing excites large populations of mechanoreceptors, generating a sensory response that is only weakly sensitive to limb displacement if the movements are small, and thus can hardly be used to determine the mobility of the object. In the mechanical world, displacement or deformation of objects frequently co-occurs with microscopic fluctuations associated with the frictional sliding of surfaces in contact or with micro-failures inside an object. In this study, we provide compelling evidence that the brain relies on these microscopic mechanical events to estimate the displacement of the limb in contact with an object, and hence the mobility of the touched object. We show that when pressing with a finger on a stiff surface, fluctuations that resemble the mechanical response of granular solids provoke a sensation of limb displacement. Our findings suggest that when acting on an external object, prior knowledge about the sensory consequences of interacting with the object contributes to proprioception. PMID:26311672

  13. Fiber optic multimode displacement sensor

    SciTech Connect

    Fisher, K.A.; Jarzynski, J.

    1996-04-01

    An underwater Optical Motion Sensor (OMS) based on a design first presented by W. B. Spillman, {ital Schlieren} {ital multimode} {ital fiber}-{ital optic} {ital hydrophone}, Applied Physics Letters 37(2), 15 July 1980, p. 145{endash}146 is described. The displacement sensor uses the same acoustooptical intensity modulation mechanism as Spillman, however the sensing mechanism is isolated from the ambient fluid environment by a small cylindrical aluminum enclosure (1{double_prime} OD{times}3/4{double_prime}). The enclosure contains an inertial mass and the fiber collimators. The inertial mass is suspended in the center of the enclosure by three small wires rigidly mounted to the walls. The mass and wires act as a cantilever beam system with a mechanical resonance near 100 Hz. The transduction mechanism consists of two opposed optical gratings aligned and positioned between the fiber collimators. One grating is mounted on the inertial mass while the other is mounted on the lower end cap of the enclosure. Relative motion between the gratings causes a modulation of the light transmitted through the gratings. The modulated beam is focused onto a photodetector and converted to electric current. The frequency response is flat from 200 Hz{endash}9 kHz with a minimum detectable displacement of 0.002 A and the dynamic range is 136 dB. The small size and light weight give the sensor an effective density of 1.08 g/cm{sup 3} making it almost neutrally buoyant in water. This in conjunction with the performance characteristics make this sensor suitable for use in acoustical sensing applications. {copyright} {ital 1996 American Institute of Physics.}

  14. Molecular dynamics studies of displacement cascades in Fe-Y2TiO5 system

    NASA Astrophysics Data System (ADS)

    Dholakia, Manan; Chandra, Sharat; Jaya, S. Mathi

    2016-05-01

    The effect of displacement cascade on Fe-Y2TiO5 bilayer is studied using classical molecular dynamics simulations. Different PKA species - Fe, Y, Ti and O - with the same PKA energy of 8 keV are used to produce displacement cascades that encompass the interface. It is shown that Ti atom has the highest movement in the ballistic regime of cascades which can lead to Ti atoms moving out of the oxide clusters into the Fe matrix in ODS alloys.

  15. Measurement of a Large Chemical Reaction Rate between Ultracold Closed-Shell {sup 40}Ca Atoms and Open-Shell {sup 174}Yb{sup +} Ions Held in a Hybrid Atom-Ion Trap

    SciTech Connect

    Rellergert, Wade G.; Sullivan, Scott T.; Chen Kuang; Schowalter, Steven J.; Hudson, Eric R.; Kotochigova, Svetlana; Petrov, Alexander

    2011-12-09

    Ultracold {sup 174}Yb{sup +} ions and {sup 40}Ca atoms are confined in a hybrid trap. The charge exchange chemical reaction rate constant between these two species is measured and found to be 4 orders of magnitude larger than recent measurements in other heteronuclear systems. The structure of the CaYb{sup +} molecule is determined and used in a calculation that explains the fast chemical reaction as a consequence of strong radiative charge transfer. A possible explanation is offered for the apparent contradiction between typical theoretical predictions and measurements of the radiative association process in this and other recent experiments.

  16. Juvenile Songbirds Compensate for Displacement to Oceanic Islands during Autumn Migration

    PubMed Central

    Thorup, Kasper; Ortvad, Troels Eske; Rabøl, Jørgen; Holland, Richard A.; Tøttrup, Anders P.; Wikelski, Martin

    2011-01-01

    To what degree juvenile migrant birds are able to correct for orientation errors or wind drift is still largely unknown. We studied the orientation of passerines on the Faroe Islands far off the normal migration routes of European migrants. The ability to compensate for displacement was tested in naturally occurring vagrants presumably displaced by wind and in birds experimentally displaced 1100 km from Denmark to the Faroes. The orientation was studied in orientation cages as well as in the free-flying birds after release by tracking departures using small radio transmitters. Both the naturally displaced and the experimentally displaced birds oriented in more easterly directions on the Faroes than was observed in Denmark prior to displacement. This pattern was even more pronounced in departure directions, perhaps because of wind influence. The clear directional compensation found even in experimentally displaced birds indicates that first-year birds can also possess the ability to correct for displacement in some circumstances, possibly involving either some primitive form of true navigation, or ‘sign posts’, but the cues used for this are highly speculative. We also found some indications of differences between species in the reaction to displacement. Such differences might be involved in the diversity of results reported in displacement studies so far. PMID:21464975

  17. Numerical simulations of immiscible displacement in the cavities via lattice Boltzmann method

    NASA Astrophysics Data System (ADS)

    Liang, Hong; Chai, Zhenhua; Shi, Baochang; Guo, Zhaoli; Li, Qiuxiang

    2015-12-01

    In this paper, the immiscible displacements in the different cavities are studied by the pseudo-potential lattice Boltzmann (LB) model. We first validate the model with a two-dimensional (2D) layered flow, and find that the numerical results agree well with the corresponding analytical solutions. Then, we perform some numerical simulations to study the immiscible displacements in the cavities, and focus on the effects of the surface wettability, capillary number and density ratio on the displacement efficiency. The numerical results show that the displacement efficiency increases with the increase of the capillary number at first and then presents a decrease with the capillary number when it is large enough. The increase of the contact angle θ1 or decrease of the density ratio increases the displacement efficiency but decreases the critical capillary number. Finally, it is also found that both the size and geometry of cavity have a significant influence on the displacement efficiency.

  18. Modelling Toehold-Mediated RNA Strand Displacement

    PubMed Central

    Šulc, Petr; Ouldridge, Thomas E.; Romano, Flavio; Doye, Jonathan P.K.; Louis, Ard A.

    2015-01-01

    We study the thermodynamics and kinetics of an RNA toehold-mediated strand displacement reaction with a recently developed coarse-grained model of RNA. Strand displacement, during which a single strand displaces a different strand previously bound to a complementary substrate strand, is an essential mechanism in active nucleic acid nanotechnology and has also been hypothesized to occur in vivo. We study the rate of displacement reactions as a function of the length of the toehold and temperature and make two experimentally testable predictions: that the displacement is faster if the toehold is placed at the 5′ end of the substrate; and that the displacement slows down with increasing temperature for longer toeholds. PMID:25762335

  19. Displacement speeds in turbulent premixed flame simulations

    SciTech Connect

    Day, Marcus S.; Shepherd, Ian G.; Bell, J.; Grcar, Joseph F.; Lijewski, Michael J.

    2007-07-01

    The theory of turbulent premixed flames is based on acharacterization of the flame as a discontinuous surface propagatingthrough the fluid. The displacement speed, defined as the local speed ofthe flame front normal to itself, relative to the unburned fluid,provides one characterization of the burning velocity. In this paper, weintroduce a geometric approach to computing displacement speed anddiscuss the efficacy of the displacement speed for characterizing aturbulent flame.

  20. Character displacement in the fighting colours of Hetaerina damselflies

    PubMed Central

    Anderson, Christopher N.; Grether, Gregory F.

    2010-01-01

    Aggression between species is a seldom-considered but potentially widespread mechanism of character displacement in secondary sexual characters. Based on previous research showing that similarity in wing coloration directly influences interspecific territorial aggression in Hetaerina damselflies, we predicted that wing coloration would show a pattern of character displacement (divergence in sympatry). A geographical survey of four Hetaerina damselfly species in Mexico and Texas showed evidence for character displacement in both species pairs that regularly occurs sympatrically. Hetaerina titia, a species that typically has large black wing spots and small red wing spots, shifted to having even larger black spots and smaller red wing spots at sites where a congener with large red wing spots is numerically dominant (Hetaerina americana or Hetaerina occisa). Hetaerina americana showed the reverse pattern, shifting towards larger red wing spots where H. titia is numerically dominant. This pattern is consistent with the process of agonistic character displacement, but the ontogenetic basis of the shift remains to be demonstrated. PMID:20591870

  1. Character displacement in the fighting colours of Hetaerina damselflies.

    PubMed

    Anderson, Christopher N; Grether, Gregory F

    2010-12-01

    Aggression between species is a seldom-considered but potentially widespread mechanism of character displacement in secondary sexual characters. Based on previous research showing that similarity in wing coloration directly influences interspecific territorial aggression in Hetaerina damselflies, we predicted that wing coloration would show a pattern of character displacement (divergence in sympatry). A geographical survey of four Hetaerina damselfly species in Mexico and Texas showed evidence for character displacement in both species pairs that regularly occurs sympatrically. Hetaerina titia, a species that typically has large black wing spots and small red wing spots, shifted to having even larger black spots and smaller red wing spots at sites where a congener with large red wing spots is numerically dominant (Hetaerina americana or Hetaerina occisa). Hetaerina americana showed the reverse pattern, shifting towards larger red wing spots where H. titia is numerically dominant. This pattern is consistent with the process of agonistic character displacement, but the ontogenetic basis of the shift remains to be demonstrated. PMID:20591870

  2. Displacement of Propagating Squeezed Microwave States.

    PubMed

    Fedorov, Kirill G; Zhong, L; Pogorzalek, S; Eder, P; Fischer, M; Goetz, J; Xie, E; Wulschner, F; Inomata, K; Yamamoto, T; Nakamura, Y; Di Candia, R; Las Heras, U; Sanz, M; Solano, E; Menzel, E P; Deppe, F; Marx, A; Gross, R

    2016-07-01

    Displacement of propagating quantum states of light is a fundamental operation for quantum communication. It enables fundamental studies on macroscopic quantum coherence and plays an important role in quantum teleportation protocols with continuous variables. In our experiments, we have successfully implemented this operation for propagating squeezed microwave states. We demonstrate that, even for strong displacement amplitudes, there is no degradation of the squeezing level in the reconstructed quantum states. Furthermore, we confirm that path entanglement generated by using displaced squeezed states remains constant over a wide range of the displacement power. PMID:27447495

  3. Displacement of Propagating Squeezed Microwave States

    NASA Astrophysics Data System (ADS)

    Fedorov, Kirill G.; Zhong, L.; Pogorzalek, S.; Eder, P.; Fischer, M.; Goetz, J.; Xie, E.; Wulschner, F.; Inomata, K.; Yamamoto, T.; Nakamura, Y.; Di Candia, R.; Las Heras, U.; Sanz, M.; Solano, E.; Menzel, E. P.; Deppe, F.; Marx, A.; Gross, R.

    2016-07-01

    Displacement of propagating quantum states of light is a fundamental operation for quantum communication. It enables fundamental studies on macroscopic quantum coherence and plays an important role in quantum teleportation protocols with continuous variables. In our experiments, we have successfully implemented this operation for propagating squeezed microwave states. We demonstrate that, even for strong displacement amplitudes, there is no degradation of the squeezing level in the reconstructed quantum states. Furthermore, we confirm that path entanglement generated by using displaced squeezed states remains constant over a wide range of the displacement power.

  4. Liquid atomization

    NASA Astrophysics Data System (ADS)

    Bayvel, L.; Orzechowski, Z.

    The present text defines the physical processes of liquid atomization, the primary types of atomizers and their design, and ways of measuring spray characteristics; it also presents experimental investigation results on atomizers and illustrative applications for them. Attention is given to the macrostructural and microstructural parameters of atomized liquids; swirl, pneumatic, and rotary atomizers; and optical drop sizing methods, with emphasis on nonintrusive optical methods.

  5. Estimating temperature-dependent anisotropic hydrogen displacements with the invariom database and a new segmented rigid-body analysis program

    PubMed Central

    Lübben, Jens; Bourhis, Luc J.; Dittrich, Birger

    2015-01-01

    Invariom partitioning and notation are used to estimate anisotropic hydrogen displacements for incorporation in crystallographic refinement models. Optimized structures of the generalized invariom database and their frequency computations provide the information required: frequencies are converted to internal atomic displacements and combined with the results of a TLS (translation–libration–screw) fit of experimental non-hydrogen anisotropic displacement parameters to estimate those of H atoms. Comparison with TLS+ONIOM and neutron diffraction results for four example structures where high-resolution X-ray and neutron data are available show that electron density transferability rules established in the invariom approach are also suitable for streamlining the transfer of atomic vibrations. A new segmented-body TLS analysis program called APD-Toolkit has been coded to overcome technical limitations of the established program THMA. The influence of incorporating hydrogen anisotropic displacement parameters on conventional refinement is assessed. PMID:26664341

  6. Polybenzoxazole via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1993-01-01

    Polybenzoxazoles (PBO) are heterocyclic macromolecules which were first synthesized in a two-step process by the initial formation of aromatic diacid chlorides with bis(o-aminophenol)s through solution condensation of aromatic diacid chlorides with bis(o-aminophenol)s followed by thermal cyclodehydration. Since then several methods were utilized in their synthesis. The most common synthetic method for PBO involves a polycondensation of bis(o-aminophenol)s with aromatic diacid diphenyl esters. Another preparative route involves the solution polycondensation of the hydrochloride salts of bis(o-amino phenol)s with aromatic diacids in polyphosphoric acid. Another synthetic method involves the initial formation of poly(o-hydroxy amide)s from silylated bis(o-aminophenol)s with aromatic diacid chlorides followed by thermal cyclodehydration to PBO. A recent preparative route involves the reaction of aromatic bisphenols with bis(fluorophenyl) benzoxazoles by the displacement reaction to form PBO. The novelty of the present invention is that high molecular weight PBO of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  7. Atomic resolution studies of carbonic anhydrase II

    SciTech Connect

    Behnke, Craig A.; Le Trong, Isolde; Godden, Jeff W.; Merritt, Ethan A.; Teller, David C.; Bajorath, Jürgen; Stenkamp, Ronald E.

    2010-05-01

    The structure of human carbonic anhydrase II has been solved with a sulfonamide inhibitor at 0.9 Å resolution. Structural variation and flexibility is seen on the surface of the protein and is consistent with the anisotropic ADPs obtained from refinement. Comparison with 13 other atomic resolution carbonic anhydrase structures shows that surface variation exists even in these highly ordered isomorphous crystals. Carbonic anhydrase has been well studied structurally and functionally owing to its importance in respiration. A large number of X-ray crystallographic structures of carbonic anhydrase and its inhibitor complexes have been determined, some at atomic resolution. Structure determination of a sulfonamide-containing inhibitor complex has been carried out and the structure was refined at 0.9 Å resolution with anisotropic atomic displacement parameters to an R value of 0.141. The structure is similar to those of other carbonic anhydrase complexes, with the inhibitor providing a fourth nonprotein ligand to the active-site zinc. Comparison of this structure with 13 other atomic resolution (higher than 1.25 Å) isomorphous carbonic anhydrase structures provides a view of the structural similarity and variability in a series of crystal structures. At the center of the protein the structures superpose very well. The metal complexes superpose (with only two exceptions) with standard deviations of 0.01 Å in some zinc–protein and zinc–ligand bond lengths. In contrast, regions of structural variability are found on the protein surface, possibly owing to flexibility and disorder in the individual structures, differences in the chemical and crystalline environments or the different approaches used by different investigators to model weak or complicated electron-density maps. These findings suggest that care must be taken in interpreting structural details on protein surfaces on the basis of individual X-ray structures, even if atomic resolution data are available.

  8. Effects of Fault Displacement on Emplacement Drifts

    SciTech Connect

    F. Duan

    2000-04-25

    The purpose of this analysis is to evaluate potential effects of fault displacement on emplacement drifts, including drip shields and waste packages emplaced in emplacement drifts. The output from this analysis not only provides data for the evaluation of long-term drift stability but also supports the Engineered Barrier System (EBS) process model report (PMR) and Disruptive Events Report currently under development. The primary scope of this analysis includes (1) examining fault displacement effects in terms of induced stresses and displacements in the rock mass surrounding an emplacement drift and (2 ) predicting fault displacement effects on the drip shield and waste package. The magnitude of the fault displacement analyzed in this analysis bounds the mean fault displacement corresponding to an annual frequency of exceedance of 10{sup -5} adopted for the preclosure period of the repository and also supports the postclosure performance assessment. This analysis is performed following the development plan prepared for analyzing effects of fault displacement on emplacement drifts (CRWMS M&O 2000). The analysis will begin with the identification and preparation of requirements, criteria, and inputs. A literature survey on accommodating fault displacements encountered in underground structures such as buried oil and gas pipelines will be conducted. For a given fault displacement, the least favorable scenario in term of the spatial relation of a fault to an emplacement drift is chosen, and the analysis is then performed analytically. Based on the analysis results, conclusions are made regarding the effects and consequences of fault displacement on emplacement drifts. Specifically, the analysis will discuss loads which can be induced by fault displacement on emplacement drifts, drip shield and/or waste packages during the time period of postclosure.

  9. Dissimilarity of polar displacements in barium and lead based relaxors

    NASA Astrophysics Data System (ADS)

    Phelan, D.; Millican, J. N.; Gehring, P. M.

    2010-08-01

    Powder neutron diffraction experiments were performed on the relaxor compound, Ba(Zn1/3Nb2/3)0.95Ti0.05O3, which was recently shown to have stronger frequency dependence in its permittivity than many Pb-based relaxors (PBR), such as PbMg1/3Nb2/3O3 [L. Khemakhem et al., J. Alloys Compd. 452, 451 (2008)]. Several notable differences in structural properties were observed in the present measurements compared to PBR. In particular, much smaller atomic displacement parameters were found, especially on the A (Ba) site, which indicates that the local shifts of the Ba atoms are much smaller than the Pb shifts in PBR. Moreover, no signature of electrostrictive strain is apparent in the thermal expansion, and instead the thermal expansion is much larger at low temperatures than for PBR.

  10. Video Games, Adolescents, and the Displacement Effect

    ERIC Educational Resources Information Center

    Fisher, Carla Christine

    2012-01-01

    The displacement effect (the idea that time spent in one activity displaces time spent in other activities) was examined within the lens of adolescents' video game use and their time spent reading, doing homework, in physically active sports and activities, in creative play, and with parents and friends. Data were drawn from the Panel Study…

  11. Displaced Homemakers: Vo-Tech Workshop Guide.

    ERIC Educational Resources Information Center

    Peltier, Wanda Jo

    Written for displaced homemaker programs in vocational-technical schools, this curriculum contains material designed so that instructors can prepare student manuals appropriate to almost any educational support situation for displaced homemakers. An overview provides information on special needs groups, curriculum use, and resources and sample…

  12. 20 CFR 211.8 - Displacement allowance.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Displacement allowance. 211.8 Section 211.8 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT CREDITABLE RAILROAD COMPENSATION § 211.8 Displacement allowance. An allowance paid to an employee because he has...

  13. 20 CFR 211.8 - Displacement allowance.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Displacement allowance. 211.8 Section 211.8 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT CREDITABLE RAILROAD COMPENSATION § 211.8 Displacement allowance. An allowance paid to an employee because he has...

  14. 20 CFR 211.8 - Displacement allowance.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Displacement allowance. 211.8 Section 211.8 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT CREDITABLE RAILROAD COMPENSATION § 211.8 Displacement allowance. An allowance paid to an employee because he has...

  15. 20 CFR 211.8 - Displacement allowance.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Displacement allowance. 211.8 Section 211.8 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT CREDITABLE RAILROAD COMPENSATION § 211.8 Displacement allowance. An allowance paid to an employee because he has...

  16. 20 CFR 211.8 - Displacement allowance.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Displacement allowance. 211.8 Section 211.8 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT CREDITABLE RAILROAD COMPENSATION § 211.8 Displacement allowance. An allowance paid to an employee because he has...

  17. Capacitive Displacement Sensor With Frequency Readout

    NASA Technical Reports Server (NTRS)

    Fritsch, Klaus

    1989-01-01

    Simple displacement-measuring circuit senses capacitance between two parallel conducting plates and produces output signal, with frequency proportional to distance between plates. Principle of circuit provides advantages over other methods because of frequency-encoded output and high linearity. Used to measure displacements.

  18. Small displacement measurements with subatomic resolution by beat frequency measurements

    NASA Astrophysics Data System (ADS)

    Cíp, O.; Petrů, F.; Buchta, Z.; Lazar, J.

    2007-07-01

    In this paper a novel method for high-resolution measurement of displacements with sub-atomic resolution is described. With this method, a length change of an optical resonator is directly transformed to a radio-frequency signal. A tunable He-Ne laser is locked to a mode of the resonator using a digital signal processing technique. Heterodyne mixing of this locked laser with an iodine-stabilized He-Ne laser converts the frequency of the laser locked to the cavity into the radio-frequency region. A HF counter measures the beat frequency from which the displacement can be derived directly. This method delivers inherent linearity and sub-nanometre resolution of the displacement over a range of several micrometres. An example of the capabilities of this system is given in this paper, where it is used for checking periodic deviations of a laser interferometer system. Emphasis is put on the construction of the optical resonator, on how its narrow resonance line-width is achieved, and how the required mechanical stability is achieved. The measurement range and the scale linearity are discussed in detail. Possible applications of this method are the calibration of nano-position systems based on PZT transducers, as well as inductive and capacitive sensors.

  19. Using a 2D displacement sensor to derive 3D displacement information

    NASA Technical Reports Server (NTRS)

    Soares, Schubert F. (Inventor)

    2002-01-01

    A 2D displacement sensor is used to measure displacement in three dimensions. For example, the sensor can be used in conjunction with a pulse-modulated or frequency-modulated laser beam to measure displacement caused by deformation of an antenna on which the sensor is mounted.

  20. New displacement-based methods for optimal truss topology design

    NASA Technical Reports Server (NTRS)

    Bendsoe, Martin P.; Ben-Tal, Aharon; Haftka, Raphael T.

    1991-01-01

    Two alternate methods for maximum stiffness truss topology design are presented. The ground structure approach is used, and the problem is formulated in terms of displacements and bar areas. This large, nonconvex optimization problem can be solved by a simultaneous analysis and design approach. Alternatively, an equivalent, unconstrained, and convex problem in the displacements only can be formulated, and this problem can be solved by a nonsmooth, steepest descent algorithm. In both methods, the explicit solving of the equilibrium equations and the assembly of the global stiffness matrix are circumvented. A large number of examples have been studied, showing the attractive features of topology design as well as exposing interesting features of optimal topologies.

  1. Defect structures induced by high-energy displacement cascades in γ uranium

    NASA Astrophysics Data System (ADS)

    Miao, Yinbin; Beeler, Benjamin; Deo, Chaitanya; Baskes, Michael I.; Okuniewski, Maria A.; Stubbins, James F.

    2015-01-01

    Displacement cascade simulations were conducted for the γ uranium system based on molecular dynamics. A recently developed modified embedded atom method (MEAM) potential was employed to replicate the atomic interactions while an embedded atom method (EAM) potential was adopted to help characterize the defect structures induced by the displacement cascades. The atomic displacement process was studied by providing primary knock-on atoms (PKAs) with kinetic energies from 1 keV to 50 keV. The influence of the PKA incident direction was examined. The defect structures were analyzed after the systems were fully relaxed. The states of the self-interstitial atoms (SIAs) were categorized into various types of dumbbells, the crowdion, and the octahedral interstitial. The voids were determined to have a polyhedral shape with {1 1 0} facets. The size distribution of the voids was also obtained. The results of this study not only expand the knowledge of the microstructural evolution in irradiated γ uranium, but also provide valuable references for the radiation-induced defects in uranium alloy fuels.

  2. Defect structures induced by high-energy displacement cascades in γ uranium

    SciTech Connect

    Miao, Yinbin; Beeler, Benjamin; Deo, Chaitanya; Baskes, Michael I.; Okuniewski, Maria A.; Stubbins, James F.

    2015-01-01

    Displacement cascade simulations were conducted for the c uranium system based on molecular dynamics. A recently developed modified embedded atom method (MEAM) potential was employed to replicate the atomic interactions while an embedded atom method (EAM) potential was adopted to help characterize the defect structures induced by the displacement cascades. The atomic displacement process was studied by providing primary knock-on atoms (PKAs) with kinetic energies from 1 keV to 50 keV. The influence of the PKA incident direction was examined. The defect structures were analyzed after the systems were fully relaxed. The states of the self-interstitial atoms (SIAs) were categorized into various types of dumbbells, the crowdion, and the octahedral interstitial. The voids were determined to have a polyhedral shape with {110} facets. The size distribution of the voids was also obtained. The results of this study not only expand the knowledge of the microstructural evolution in irradiated c uranium, but also provide valuable references for the radiation-induced defects in uranium alloy fuels.

  3. Displacive radiation-induced structural contraction in nanocrystalline ZrN

    SciTech Connect

    Lu Fengyuan; Sun Hongtao; Lian Jie; Huang, Mengbing; Yaqoob, Faisal; Lang, Maik; Ewing, Rodney C.; Namavar, Fereydoon; Trautmann, Christina

    2012-07-23

    Nanocrystalline ZrN thin films with 5 nm grain size, prepared by ion beam assisted deposition, maintained their isometric structure upon intensive displacive and ionizing irradiations, indicating an extremely high stability similar to bulk ZrN. However, a unique structural contraction up to 1.42% in lattice parameter occurred only in nano-sized ZrN upon displacive irradiations. A significant nitrogen loss occurred with reduced N:Zr atomic ratio to 0.88, probably due to the production of displaced nitrogen atoms and fast diffusion along grain boundaries in nanocrystalline ZrN matrix. The accumulation of nitrogen vacancies and related strain relaxation may be responsible for the structural contraction.

  4. Analysis of Fraction Skill Score properties for a displaced rainy grid point in a rectangular domain

    NASA Astrophysics Data System (ADS)

    Skok, Gregor

    2015-04-01

    Fraction Skill Score (FSS) is a recently developed and popular metric used for precipitation verification. A compact analytical expression for FSS is derived for a case with a single displaced rainy grid point in a rectangular domain. The existence of analytical solution is used to determine some properties of FSS which might also be applicable in other cases since the rain areas of any shape will asymptote towards this solution if the displacement is sufficiently large. The use of the simple square shape of the neighborhood causes the FSS value to be dependent on the direction of the displacements (not only on the displacement size). The effect is limited in scope but can increase or decrease the FSS value by 0.1. Moving a nearby border closer to the rainy points can either increase or decrease the FSS value depending on the location of the border. The FSS value near a border can be at most 33% larger than the FSS value in the infinite domain assuming the same neighborhood and displacement. Changing the orientation of the displacement can either increase or decrease the FSS value - the effect of the nearby border is intertwined with the effect of the square shape of the neighborhood. The effect of the nearby corner is similar to the effect of the nearby border but is stronger - assuming the same diagonal displacement in both cases. The useful forecast criteria (FSSuseful) is defined as a value of FSS for a precipitation feature with displacement half the neighborhood size. FSSuseful for a displaced rainy grid point depends on the orientation of the displacement being the largest for displacements that are parallel to the borders and the smallest for a diagonal displacement where the value can be as low as 0.42.

  5. Effect of strain and temperature on the threshold displacement energy in body-centered cubic iron

    NASA Astrophysics Data System (ADS)

    Beeler, Benjamin; Asta, Mark; Hosemann, Peter; Grønbech-Jensen, Niels

    2016-06-01

    The threshold displacement energy (TDE) is the minimum amount of kinetic energy required to displace an atom from its lattice site. The magnitude of the TDE displays significant variance as a function of the crystallographic direction, system temperature and applied strain, among a variety of other factors. It is critically important to determine an accurate value of the TDE in order to calculate the total number of displacements due to a given irradiation condition, and thus to understand the materials response to irradiation. In this study, molecular dynamics simulations have been performed to calculate the threshold displacement energy in body-centered cubic iron as a function of strain and temperature. With applied strain, a decrease of the TDE of up to approximately 14 eV was observed. A temperature increase from 300 K to 500 K can result in an increase of the TDE of up to approximately 9 eV.

  6. The formation of spikes in the displacement of miscible fluids

    NASA Technical Reports Server (NTRS)

    Rashidnia, N.; Balasubramaniam, R.; Schroer, R. T.

    2004-01-01

    We report on experiments in which a more viscous fluid displaces a less viscous one in a vertical cylindrical tube. These experiments were performed using silicone oils in a vertical pipette of small diameter. The more viscous fluid also had a slightly larger density than the less viscous fluid. In the initial configuration, the fluids were at rest, and the interface was nominally flat. A dye was added to the more viscous fluid for ease of observation of the interface between the fluids. The flow was initiated by pumping the more viscous fluid into the less viscous one. The displacement velocity was such that the Reynolds number was smaller than unity and the Peclet number for mass transfer between the fluids was large compared to unity. For upward displacement of the more viscous fluid from an initially stable configuration, an axisymmetric finger was observed under all conditions. However, a needle-shaped spike was seen to propagate from the main finger in many cases, similar to that observed by Petitjeans and Maxworthy for the displacement of a more viscous fluid by a less viscous one.

  7. The role of finite displacements in vocal fold modeling.

    PubMed

    Chang, Siyuan; Tian, Fang-Bao; Luo, Haoxiang; Doyle, James F; Rousseau, Bernard

    2013-11-01

    Human vocal folds experience flow-induced vibrations during phonation. In previous computational models, the vocal fold dynamics has been treated with linear elasticity theory in which both the strain and the displacement of the tissue are assumed to be infinitesimal (referred to as model I). The effect of the nonlinear strain, or geometric nonlinearity, caused by finite displacements is yet not clear. In this work, a two-dimensional model is used to study the effect of geometric nonlinearity (referred to as model II) on the vocal fold and the airflow. The result shows that even though the deformation is under 1 mm, i.e., less than 10% of the size of the vocal fold, the geometric nonlinear effect is still significant. Specifically, model I underpredicts the gap width, the flow rate, and the impact stress on the medial surfaces as compared to model II. The study further shows that the differences are caused by the contact mechanics and, more importantly, the fluid-structure interaction that magnifies the error from the small-displacement assumption. The results suggest that using the large-displacement formulation in a computational model would be more appropriate for accurate simulations of the vocal fold dynamics. PMID:24008392

  8. Displacement thresholds in central and peripheral vision during tracking

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1986-01-01

    The effects of stimulus duration and angular velocity on a subject's judgment of displacement threshold are examined. Twenty-six male subjects between 17-45 years with uncorrected 20:20 distance acuity and normal color perception and stereopsis studied a series of forced choice, paired comparison trials in which a long, thin, collimated horizontally oriented line moved downward through 12 angles ranging from 0.6-60 arcmin and judged which stimulus moved in each pair. The displacements were produced by 0.25, 0.5, 1, 2, and 4 sec stimulus duration and 2.5, 5, 10, and 15 deg/sec angular rates. Stimulus velocity, stimulus duration, mean threshold displacement, and mean confidence results are analyzed. It is observed that displacement judgment accuracy is increased with increasing stimulus duration. The data are compared with the results of Johnson and Leibowitz (1976) and Johnson and Scobey (1982), and good correlation with the Johnson and Leibowitz data is detected. The data reveal that threshold is based on a constant stimulus velocity over this range of durations and velocities. The data are applicable to the study of the final approach to landing of medium and large commercial jet aircraft.

  9. Motional displacements in proteins incorporating dynamical diversity

    NASA Astrophysics Data System (ADS)

    Vural, Derya; Smith, Jeremy; Glyde, Henry

    The average mean square displacement (MSD), , of hydrogen H in proteins is measured using incoherent neutron scattering methods. The observed MSD shows a marked increase in magnitude at a temperature TD ~= 240 K. This is widely interpreted as a dynamical transition to large MSDs which make function possible in proteins. However, when the data is interpreted in terms of a single averaged MSD, the extracted depends on the neutron momentum transfer, ℏQ , used in the measurement. We have shown recently that this apparent dependence on Q arises because the dynamical diversity of the H in the protein is neglected[2]. We present models of the dynamical diversity of H in Lysosyme that when used in the analysis of simulated neutron data lead to consistent, Q independent values for the average MSD and for the diversity model.2. D. Vural and L. Hong, J. C. Smith and H. R. Glyde. Phys. Rev. E 91, 052705 (2015). Supported in part by Office of Basic Energy Sciences, USDOE, ER46680.

  10. Crustal Displacements Due to Continental Water Loading

    NASA Technical Reports Server (NTRS)

    vanDam, T.; Wahr, J.; Milly, P. C. D.; Shmakin, A. B.; Blewitt, G.; Lavallee, D.; Larson, K. M.

    2001-01-01

    The effects of long-wavelength (> 100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displacements (delta-r(sub M)) have root-mean-square (RMS) values for 1994-1998 as large as 8 mm with ranges up to 30 mm, and are predominantly annual in character. Regional strains are on the order of 20 nanostrain for tilt and 5 nanostrain for horizontal deformation. We compare delta-r(sub M) with observed Global Positioning System (GPS) heights (delta-r(sub O)) (which include adjustments to remove estimated effects of atmospheric pressure and annual tidal and non-tidal ocean loading) for 147 globally distributed sites. When the delta-r(sub O) time series are adjusted by delta-r(sub M), their variances are reduced, on average, by an amount equal to the variance of the delta-r(sub M). Of the delta-r(sub O) time series exhibiting a strong annual signal, more than half are found to have an annual harmonic that is in phase and of comparable amplitude with the annual harmonic in the delta-r(sub M). The delta-r(sub M) time series exhibit long-period variations that could be mistaken for secular tectonic trends or post-glacial rebound when observed over a time span of a few years.

  11. Particle displacement tracking applied to air flows

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.

    1991-01-01

    Electronic Particle Image Velocimeter (PIV) techniques offer many advantages over conventional photographic PIV methods such as fast turn around times and simplified data reduction. A new all electronic PIV technique was developed which can measure high speed gas velocities. The Particle Displacement Tracking (PDT) technique employs a single cw laser, small seed particles (1 micron), and a single intensified, gated CCD array frame camera to provide a simple and fast method of obtaining two-dimensional velocity vector maps with unambiguous direction determination. Use of a single CCD camera eliminates registration difficulties encountered when multiple cameras are used to obtain velocity magnitude and direction information. An 80386 PC equipped with a large memory buffer frame-grabber board provides all of the data acquisition and data reduction operations. No array processors of other numerical processing hardware are required. Full video resolution (640x480 pixel) is maintained in the acquired images, providing high resolution video frames of the recorded particle images. The time between data acquisition to display of the velocity vector map is less than 40 sec. The new electronic PDT technique is demonstrated on an air nozzle flow with velocities less than 150 m/s.

  12. Crustal displacements due to continental water loading

    USGS Publications Warehouse

    Van Dam, T.; Wahr, J.; Milly, P.C.D.; Shmakin, A.B.; Blewitt, G.; Lavallee, D.; Larson, K.M.

    2001-01-01

    The effects of long-wavelength (> 100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displacements (??rM) have root-mean-square (RMS) values for 1994-1998 as large as 8 mm, with ranges up to 30 mm, and are predominantly annual in character. Regional strains are on the order of 20 nanostrain for tilt and 5 nanostrain for horizontal deformation. We compare ??rM with observed Global Positioning System (GPS) heights (??rO) (which include adjustments to remove estimated effects of atmospheric pressure and annual tidal and non-tidal ocean loading) for 147 globally distributed sites. When the ??rO time series are adjusted by ??rM, their variances are reduced, on average, by an amount equal to the variance of the ??rM. Of the ??rO time series exhibiting a strong annual signal, more than half are found to have an annual harmonic that is in phase and of comparable amplitude with the annual harmonic in the ??rM. The ??rM time series exhibit long-period variations that could be mistaken for secular tectonic trends or post-glacial rebound when observed over a time span of a few years.

  13. Rotor Displacement of the Ultrasonic Motor Having an Angular Displacement Self-Correction Function

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoduo; Kusakabe, Chiharu; Tomikawa, Yoshiro; Takano, Takehiro

    1993-09-01

    This paper deals with the experimental investigation for confirmation of rotor displacement of the ultrasonic stepping motor having an angular displacement self-correction function. The experiment focused on the relationship between the rotor’s vibration displacement and its staying position for the self-correction. The result proved that the rotor always stays at the position where the displacement is smallest by cutting a slit into the rotor. Moreover, it has also been found that the stable self-correction of rotor angular displacement depends upon both the rotor driving frequency and rotor clamping force.

  14. An expanded calibration study of the explicitly correlated CCSD(T)-F12b method using large basis set standard CCSD(T) atomization energies

    NASA Astrophysics Data System (ADS)

    Feller, David; Peterson, Kirk A.

    2013-08-01

    The effectiveness of the recently developed, explicitly correlated coupled cluster method CCSD(T)-F12b is examined in terms of its ability to reproduce atomization energies derived from complete basis set extrapolations of standard CCSD(T). Most of the standard method findings were obtained with aug-cc-pV7Z or aug-cc-pV8Z basis sets. For a few homonuclear diatomic molecules it was possible to push the basis set to the aug-cc-pV9Z level. F12b calculations were performed with the cc-pVnZ-F12 (n = D, T, Q) basis set sequence and were also extrapolated to the basis set limit using a Schwenke-style, parameterized formula. A systematic bias was observed in the F12b method with the (VTZ-F12/VQZ-F12) basis set combination. This bias resulted in the underestimation of reference values associated with small molecules (valence correlation energies <0.5 Eh) and an even larger overestimation of atomization energies for bigger systems. Consequently, caution should be exercised in the use of F12b for high accuracy studies. Root mean square and mean absolute deviation error metrics for this basis set combination were comparable to complete basis set values obtained with standard CCSD(T) and the aug-cc-pVDZ through aug-cc-pVQZ basis set sequence. However, the mean signed deviation was an order of magnitude larger. Problems partially due to basis set superposition error were identified with second row compounds which resulted in a weak performance for the smaller VDZ-F12/VTZ-F12 combination of basis sets.

  15. Atomic polarizabilities

    SciTech Connect

    Safronova, M. S.; Mitroy, J.; Clark, Charles W.; Kozlov, M. G.

    2015-01-22

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.

  16. Modeling averaged displacement fronts in heterogeneous media with multirate mass transfer models

    NASA Astrophysics Data System (ADS)

    Neuweiler, Insa; Heiss, Veronica; Tecklenburg, Jan

    2013-04-01

    The morphology of fluid-fluid interfaces during immiscible displacement has been studied intensely on length scales where the pore space is resolved. Depending on the dimensionless numbers of the flow process, the front morphology can be different: compact or irregular with different cluster distributions of trapped displaced fluid. There are also flow regimes with a cross-over from a compact displacing fluid far away from the front and irregular fluid distribution at the front. If displacement is considered on larger length scales, the pore space and fluid-fluid interfaces can no longer be resolved. The front is in this case rather described by an isoline of the displacing fluid saturation. Displacement fronts on large length scales in heterogeneous media can also show complex front morphology: compact or irregular with fluid clusters of displaced fluid that are trapped behind the front. As displaced fluid may also be immobilized (meaning it is not trapped, but it is surrounded by displacing fluid, so that the surrounding material has a very low permeability) and is in this case displaced only very slowly, one also finds a cross-over regime with a compact region far away from the front and an irregular front. The morphology is influenced by the interplay of heterogeneous structure and the stability of the displacement process. We focus on displacement scenarios with crossover from irregular fluid distribution around the front due to immobilized fluid that is eventually displaced to compact far behind the front. To have a quantification of the front morphology is important, for example, to estimate mass transfer of given components between the fluids. We study the front morphology using numerical simulations of displacement processes in porous media composed of two different materials. We consider different heterogeneous structures. We consider flow scenarios with different capillary number and viscosity ratio of the fluids. It is demonstrated that the connectivity

  17. PDT - PARTICLE DISPLACEMENT TRACKING SOFTWARE

    NASA Technical Reports Server (NTRS)

    Wernet, M. P.

    1994-01-01

    Particle Imaging Velocimetry (PIV) is a quantitative velocity measurement technique for measuring instantaneous planar cross sections of a flow field. The technique offers very high precision (1%) directionally resolved velocity vector estimates, but its use has been limited by high equipment costs and complexity of operation. Particle Displacement Tracking (PDT) is an all-electronic PIV data acquisition and reduction procedure which is simple, fast, and easily implemented. The procedure uses a low power, continuous wave laser and a Charged Coupled Device (CCD) camera to electronically record the particle images. A frame grabber board in a PC is used for data acquisition and reduction processing. PDT eliminates the need for photographic processing, system costs are moderately low, and reduced data are available within seconds of acquisition. The technique results in velocity estimate accuracies on the order of 5%. The software is fully menu-driven from the acquisition to the reduction and analysis of the data. Options are available to acquire a single image or 5- or 25-field series of images separated in time by multiples of 1/60 second. The user may process each image, specifying its boundaries to remove unwanted glare from the periphery and adjusting its background level to clearly resolve the particle images. Data reduction routines determine the particle image centroids and create time history files. PDT then identifies the velocity vectors which describe the particle movement in the flow field. Graphical data analysis routines are included which allow the user to graph the time history files and display the velocity vector maps, interpolated velocity vector grids, iso-velocity vector contours, and flow streamlines. The PDT data processing software is written in FORTRAN 77 and the data acquisition routine is written in C-Language for 80386-based IBM PC compatibles running MS-DOS v3.0 or higher. Machine requirements include 4 MB RAM (3 MB Extended), a single or

  18. Optimization of legacy lidar data sets for measuring near-field earthquake displacements

    NASA Astrophysics Data System (ADS)

    Glennie, Craig L.; Hinojosa-Corona, Alejandro; Nissen, Edwin; Kusari, Arpan; Oskin, Michael E.; Arrowsmith, J. Ramon; Borsa, Adrian

    2014-05-01

    Airborne lidar (light detection and ranging) topography, acquired before and after an earthquake, can provide an estimate of the coseismic surface displacement field by differencing the preevent and postevent lidar point clouds. However, estimated displacements can be contaminated by the presence of large systematic errors in either of the point clouds. We present three-dimensional displacements obtained by differencing airborne lidar point clouds collected before and after the El Mayor-Cucapah earthquake, a Mw 7.2 earthquake that occurred in 2010. The original surface displacement estimates contained large, periodic artifacts caused by systematic errors in the preevent lidar data. Reprocessing the preevent data, detailed herein, removed a majority of these systematic errors that were largely due to misalignment between the scanning mirror and the outgoing laser beam. The methodology presented can be applied to other legacy airborne laser scanning data sets in order to improve change estimates from temporally spaced lidar acquisitions.

  19. Probing baryogenesis with displaced vertices at the LHC

    NASA Astrophysics Data System (ADS)

    Cui, Yanou; Shuve, Brian

    2015-02-01

    The generation of the asymmetric cosmic baryon abundance requires a departure from thermal equilibrium in the early universe. In a large class of baryogenesis models, the baryon asymmetry results from the out-of-equilibrium decay of a new, massive particle. We highlight that in the interesting scenario where this particle has a weak scale mass, this out-of-equilibrium condition requires a proper decay length larger than O(1) mm. Such new fields are within reach of the LHC, at which they can be pair produced leaving a distinctive, displaced-vertex signature. This scenario is realized in the recently proposed mechanism of baryogenesis where the baryon asymmetry is produced through the freeze-out and subsequent decay of a meta-stable weakly interacting massive particle ("WIMP baryogenesis"). In analogy to missing energy searches for WIMP dark matter, the LHC is an excellent probe of these new long-lived particles responsible for baryogenesis via the low-background displaced vertex channel. In our paper, we estimate the limits on simplified models inspired by WIMP baryogenesis from two of the most sensitive collider searches by CMS and ATLAS with 8 TeV LHC data. We also estimate the LHC reach at 13 TeV using current strategies, and demonstrate that up to a factor of 100 improvement in cross-section limits can be achieved by requiring two displaced vertices while lowering kinematic thresholds. For meta-stable WIMPs produced through electroweak interactions, the high luminosity LHC is sensitive to masses up to 2.5 TeV for lifetimes around 1 cm, while for singlets pair-produced through the off-shell-Higgs portal, the LHC is sensitive to production cross sections of O(10) ab for benchmark masses around 150 GeV. Our analysis and proposals also generally apply to displaced vertex signatures from other new physics such as hidden valley models, twin Higgs models and displaced supersymmetry.

  20. Refugees and displaced persons. War, hunger, and public health.

    PubMed

    Toole, M J; Waldman, R J

    1993-08-01

    The number of refugees and internally displaced persons in need of protection and assistance has increased from 30 million in 1990 to more than 43 million today. War and civil strife have been largely responsible for this epidemic of mass migration that has affected almost every region of the world, including Europe. Since 1990, crude death rates (CDRs) during the early influx of refugees who crossed international borders have been somewhat lower than CDRs reported earlier among Cambodian and Ethiopian refugees. Nevertheless, CDRs among refugees arriving in Ethiopia, Kenya, Nepal, Malawi, and Zimbabwe since 1990 ranged from five to 12 times the baseline CDRs in the countries of origin. Among internally displaced populations in northern Iraq, Somalia, and Sudan, CDRs were extremely high, ranging from 12 to 25 times the baseline CDRs for the nondisplaced. Among both refugees and internally displaced persons, death rates among children less than 5 years of age were far higher than among older children and adults. In Bangladesh, the death rate in female Rohingya refugees was several times higher than in males. Preventable conditions such as diarrheal disease, measles, and acute respiratory infections, exacerbated often by malnutrition, caused most deaths. Although relief programs for refugees have improved since 1990, the situation among the internally displaced may have worsened. The international community should intervene earlier in the evolution of complex disasters involving civil war, human rights abuses, food shortages, and mass displacement. Relief programs need to be based on sound health and nutrition information and should focus on the provision of adequate shelter, food, water, sanitation, and public health programs that prevent mortality from diarrhea, measles, and other communicable diseases, especially among young children and women. PMID:8331759

  1. Fault displacement hazard for strike-slip faults

    USGS Publications Warehouse

    Petersen, M.D.; Dawson, T.E.; Chen, R.; Cao, T.; Wills, C.J.; Schwartz, D.P.; Frankel, A.D.

    2011-01-01

    In this paper we present a methodology, data, and regression equations for calculating the fault rupture hazard at sites near steeply dipping, strike-slip faults. We collected and digitized on-fault and off-fault displacement data for 9 global strikeslip earthquakes ranging from moment magnitude M 6.5 to M 7.6 and supplemented these with displacements from 13 global earthquakes compiled byWesnousky (2008), who considers events up to M 7.9. Displacements on the primary fault fall off at the rupture ends and are often measured in meters, while displacements on secondary (offfault) or distributed faults may measure a few centimeters up to more than a meter and decay with distance from the rupture. Probability of earthquake rupture is less than 15% for cells 200 m??200 m and is less than 2% for 25 m??25 m cells at distances greater than 200mfrom the primary-fault rupture. Therefore, the hazard for off-fault ruptures is much lower than the hazard near the fault. Our data indicate that rupture displacements up to 35cm can be triggered on adjacent faults at distances out to 10kmor more from the primary-fault rupture. An example calculation shows that, for an active fault which has repeated large earthquakes every few hundred years, fault rupture hazard analysis should be an important consideration in the design of structures or lifelines that are located near the principal fault, within about 150 m of well-mapped active faults with a simple trace and within 300 m of faults with poorly defined or complex traces.

  2. Efficiency Improvements to the Displacement Based Multilevel Structural Optimization Algorithm

    NASA Technical Reports Server (NTRS)

    Plunkett, C. L.; Striz, A. G.; Sobieszczanski-Sobieski, J.

    2001-01-01

    Multilevel Structural Optimization (MSO) continues to be an area of research interest in engineering optimization. In the present project, the weight optimization of beams and trusses using Displacement based Multilevel Structural Optimization (DMSO), a member of the MSO set of methodologies, is investigated. In the DMSO approach, the optimization task is subdivided into a single system and multiple subsystems level optimizations. The system level optimization minimizes the load unbalance resulting from the use of displacement functions to approximate the structural displacements. The function coefficients are then the design variables. Alternately, the system level optimization can be solved using the displacements themselves as design variables, as was shown in previous research. Both approaches ensure that the calculated loads match the applied loads. In the subsystems level, the weight of the structure is minimized using the element dimensions as design variables. The approach is expected to be very efficient for large structures, since parallel computing can be utilized in the different levels of the problem. In this paper, the method is applied to a one-dimensional beam and a large three-dimensional truss. The beam was tested to study possible simplifications to the system level optimization. In previous research, polynomials were used to approximate the global nodal displacements. The number of coefficients of the polynomials equally matched the number of degrees of freedom of the problem. Here it was desired to see if it is possible to only match a subset of the degrees of freedom in the system level. This would lead to a simplification of the system level, with a resulting increase in overall efficiency. However, the methods tested for this type of system level simplification did not yield positive results. The large truss was utilized to test further improvements in the efficiency of DMSO. In previous work, parallel processing was applied to the

  3. Is Stereocilia Velocity or Displacement Feedback Used in the Cochlear Amplifier?

    NASA Astrophysics Data System (ADS)

    Lu, Shan; Mountain, David; Hubbard, Allyn

    2009-02-01

    Outer hair cells (OHC) play an important role in cochlear amplification. The OHC senses stereocilia motion and creates a force feedback to the organ of Corti. It is largely accepted that the stereocilia displacement drives the OHC apical conductance change, which, in turn, drives somatic motility. Recent research shows that the tension gated OHC current exhibits fast adaptation in response to stereocilia displacement. Such an adaptation process resembles a high-pass filter or differentiator, at least for the inward current. Since velocity is the derivative of displacement, fast adaptation may indicate that it is the stereocilia velocity, rather than displacement is the more important driver of the OHC apical conductance. We changed our multi-compartment, piezo-electro-mechanical model to sense stereocilia velocity rather than displacement. This new model can well match measured basilar membrane velocity and our own cochlear microphonic data.

  4. Experimental verification of displacement-current conduits in metamaterials-inspired optical circuitry.

    PubMed

    Edwards, Brian; Engheta, Nader

    2012-05-11

    Electric displacement current is present in capacitors and optical waveguides; however, unlike the conduction current in metallic wires, it is not confined. Analogous to the contrast in conductivity between a metallic wire and the surrounding air, displacement-current wires based on near-zero permittivity media contain a large contrast in effective permittivity. As a variation on this idea, in this Letter, we demonstrate at microwave frequencies two displacement-current cables based on effectively negative and effectively positive permittivity metastructures. Our experimental results clearly show cablelike behaviors that allow bending of the structure while still confining and maintaining the primarily longitudinal forward and reverse effective displacement currents within each conduit. The results presented here experimentally verify the notion of displacement-current wires and cables in metatronics as metamaterial-inspired circuitry. PMID:23003040

  5. Electrode system for electric-discharge generation of atomic iodine in a repetitively pulsed oxygen - iodine laser with a large active volume

    SciTech Connect

    Kazantsev, S Yu; Kononov, I G; Podlesnykh, S V; Firsov, K N

    2010-08-03

    Possibilities for increasing the active medium volume of a chemical oxygen - iodine laser (CCOIL) with a pulsed electric-discharge generation of atomic iodine are studied. The reasons are analysed of the low stability of the transverse self-sustained volume discharge in electrode systems with metal cathodes under the conditions of the electric energy input into gas-discharge plasma that are typical for CCOILs: low pressure of mixtures containing a strongly electronegative component, low voltage of discharge burning, low specific energy depositions, and long duration of the current pulse. An efficient electrode system is elaborated with the cathode based on an anisotropically-resistive material, which resulted in a stable discharge in the mixtures of iodide (CH{sub 3}I, n-C{sub 3}H{sub 7}I, C{sub 2}H{sub 5}I) with oxygen and nitrogen at the specific energy depositions of {approx}5 J L{sup -1}, pressures of 10 - 25 Torr, and mixture volume of 2.5 L. (lasers)

  6. Seismic transducer measures small horizontal displacements

    NASA Technical Reports Server (NTRS)

    Greenwood, T. L.

    1965-01-01

    Pendular seismic transducer mounted on base plate measures small horizontal displacements of structures subjected to vibration where no fixed reference point is available. Enclosure of transducer in transparent plastic case prevents air currents from disturbing the pendulum balance.

  7. Amorphous wires in displacement sensing techniques

    NASA Astrophysics Data System (ADS)

    Hristoforou, E.; Niarchos, D.

    1992-10-01

    In this paper, a new displacement sensor is proposed which is based on the magnetostrictive delay line technique (MDL). Due to this technique, the displacement of a moving magnet at either the acoustic stress point of origin or the detecting coil can be sensed, due to the change of the peak value of the output voltage. This sensor uses the recently developed FeSiB and FeCoCrSiB amorphous wires. Reported results show a linear response for defined regions of displacement, and a monotonic one for the case of the 125 μm FeSiB wires. It is also shown that this sensor arrangement can be used for fabrication of displacement distribution integrated sensors. Finally, it is shown that use of amorphous wires makes the repeatability of the response of the sensor as accurate as 0.6% without using hardware or software calibration.

  8. Giant adrenal cyst displacing the right kidney

    PubMed Central

    Chodisetti, Subbarao; Boddepalli, Yogesh; Kota, Malakondareddy

    2016-01-01

    Adrenal cysts are rare and should be considered in the differential diagnosis of retroperitoneal cysts. We present a case of a huge adrenal cyst displacing the right kidney anteriorly toward the left side in a young female. PMID:26941503

  9. Probing neutrino mass with displaced vertices at the Fermilab Tevatron

    SciTech Connect

    Campos, F. de; Eboli, O.J.P.; Magro, M.B.; Porod, W.; Restrepo, D.; Valle, J.W.F.

    2005-04-01

    Supersymmetric extensions of the standard model exhibiting bilinear R-parity violation can generate naturally the observed neutrino mass spectrum as well as mixings. One interesting feature of these scenarios is that the lightest supersymmetric particle (LSP) is unstable, with several of its decay properties predicted in terms of neutrino mixing angles. A smoking gun of this model in colliders is the presence of displaced vertices due to LSP decays in large parts of the parameter space. In this work we focus on the simplest model of this type that comes from minimal supergravity with universal R-parity conserving soft breaking of supersymmetry augmented with bilinear R-parity breaking terms at the electroweak scale (RmSUGRA). We evaluate the potential of the Fermilab Tevatron to probe the RmSUGRA parameters through the analysis of events possessing two displaced vertices stemming from LSP decays. We show that requiring two displaced vertices in the events leads to a reach in m{sub 1/2} twice the one in the usual multilepton signals in a large fraction of the parameter space.

  10. Inverted liver with suprahepatic, anteriorly displaced gallbladder.

    PubMed

    Hibbs, Harold; Ahmad, Usman

    2010-01-01

    A suprahepatic, anteriorly displaced gallbladder in association with an inverted liver is an extremely rare congenital anomaly. We report the clinical and radiologic findings associated with a 78-year-old woman presenting with shortness of breath, desaturation, hypercapnia and hypoxemia. An abnormal chest radiograph demonstrated right hemi-diaphragmatic elevation consistent with a possible eventration. Subsequent imaging by computed tomography (CT) demonstrated an inverted liver with an anteriorly displaced, suprahepatic gallbladder. PMID:20666167

  11. Analysis of Fraction Skill Score properties for a displaced rainy grid point in a rectangular domain

    NASA Astrophysics Data System (ADS)

    Skok, Gregor

    2016-03-01

    The Fraction Skill Score (FSS) is a recently developed and popular metric used for precipitation verification. A compact analytical expression for FSS is derived for a case with a single displaced rainy grid point in a rectangular domain. The existence of an analytical solution is used to determine some properties of FSS, which might also be applicable in other cases since the rain areas of any shape will asymptote towards this solution if the displacement is sufficiently large. The use of the simple square shape of the neighborhood causes the FSS value to be dependent on the direction of the displacements (not only on the displacement size). The effect is limited in scope but can increase or decrease the FSS value by 0.1. Moving a nearby border closer to the rainy points can either increase or decrease the FSS value, depending on the location of the border. The FSS value near a border can be at most 33% larger than the FSS value in the infinite domain, assuming the same neighborhood size and displacement. The effect of the nearby corner is similar to the effect of the nearby border but is stronger. The useful forecast criteria (FSSuseful) is defined as a value of FSS for a precipitation feature with a displacement half the neighborhood size. FSSuseful for a displaced rainy grid point depends on the orientation of the displacement being the largest for displacements that are parallel to the borders and the smallest for a diagonal displacement for which the value can be as low as 0.42. An analysis of a real dataset was also performed, which showed that the border effect is usually small, but in some cases the effect becomes large (an increase of FSS value up to 70% was identified). The likelihood of a strong border effect in real datasets increases significantly if the neighborhood size at FSS = 0.5 is comparable or larger than the domain size.

  12. Displacement sensor for indoor machine calibrations.

    PubMed

    Mudassar, Asloob Ahmad; Butt, Saira

    2013-05-20

    This paper presents a simple displacement sensor for indoor machine calibrations. The sensor, which is placed in the path of a diverging laser beam, consists of two plane mirror pieces laterally displaced with the line joining their centers initially held perpendicular to the optical axis of the beam during the displacement of the sensor with one of the mirrors always traveling along the optical axis of the laser beam. The optical signals from the two mirrors are combined and a simple detector at the interference plane counts the fringes during the sensor displacement. The sensor could be mounted on the moving head of any mechanical machine, e.g., the lathe machine for displacement calibration. The device has been tested over a range of 10 cm beyond a distance of 150 cm from a diverging laser source giving an accuracy of 1.1015 μm. Theoretical modeling, simulation, and experimental results are presented which establish that the proposed sensor can be used as a promising displacement measuring device. PMID:23736230

  13. Earthquake-induced soil displacements and their impact on rehabilitations.

    PubMed

    Konagai, Kazuo

    2011-01-01

    A large earthquake can trigger long lasting geotechnical problems, which pose serious issues on both rehabilitations and land conservations. Therefore one of what required of us is to deduce as much hidden signs as possible from observable changes of landforms. Though serious, damage caused by the October 23rd 2004, Mid-Niigata Prefecture Earthquake has given us a rare opportunity to study the landform changes in mountainous terrain hit by this earthquake. An attempt was made to convert changes in elevation in Eulerian description for images obtained from remote-sensing technologies to Lagrangian displacements, because Lagrangian displacements can directly describe behaviors of soils, which are typically history-dependent. This paper documents some big pictures of earthquake-inflicted landform changes obtained through this attempt. PMID:21986310

  14. Earthquake-induced soil displacements and their impact on rehabilitations

    PubMed Central

    KONAGAI, Kazuo

    2011-01-01

    A large earthquake can trigger long lasting geotechnical problems, which pose serious issues on both rehabilitations and land conservations. Therefore one of what required of us is to deduce as much hidden signs as possible from observable changes of landforms. Though serious, damage caused by the October 23rd 2004, Mid-Niigata Prefecture Earthquake has given us a rare opportunity to study the landform changes in mountainous terrain hit by this earthquake. An attempt was made to convert changes in elevation in Eulerian description for images obtained from remote-sensing technologies to Lagrangian displacements, because Lagrangian displacements can directly describe behaviors of soils, which are typically history-dependent. This paper documents some big pictures of earthquake-inflicted landform changes obtained through this attempt. PMID:21986310

  15. Efficient Displacement Discontinuity Method Using Fast Multipole Techniques

    SciTech Connect

    Morris, J.P.; Blair, S.C.

    2000-02-18

    The Displacement Discontinuity method has been widely used in geomechanics because it accurately captures the behavior of fractures within a rock mass by explicitly accounting for discontinuities. Unfortunately, boundary element techniques require the interactions between all pairs of elements to be evaluated and traditional approaches to the Displacement Discontinuity method are computationally expensive for large problem sizes. Approximate summation techniques, such as the Fast Multipole Method (FMM), calculate the interactions between N entities in time proportional to N. We have implemented a modified Fast Multipole approach which performs the necessary calculations in optimal time and with reduced memory usage. Furthermore, the FMM introduces parameters which can be selected to give the desired trade-off between efficiency and accuracy. The FMM approach permits much larger problems to be solved using desktop computers, opening up a range of applications. We present results demonstrating the speed of the code and several test cases involving rock fracture in compression.

  16. Bifurcation, chaos, and scan instability in dynamic atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Cantrell, John H.; Cantrell, Sean A.

    2016-03-01

    The dynamical motion at any point on the cantilever of an atomic force microscope can be expressed quite generally as a superposition of simple harmonic oscillators corresponding to the vibrational modes allowed by the cantilever shape. Central to the dynamical equations is the representation of the cantilever-sample interaction force as a polynomial expansion with coefficients that account for the interaction force "stiffness," the cantilever-to-sample energy transfer, and the displacement amplitude of cantilever oscillation. Renormalization of the cantilever beam model shows that for a given cantilever drive frequency cantilever dynamics can be accurately represented by a single nonlinear mass-spring model with frequency-dependent stiffness and damping coefficients [S. A. Cantrell and J. H. Cantrell, J. Appl. Phys. 110, 094314 (2011)]. Application of the Melnikov method to the renormalized dynamical equation is shown to predict a cascade of period doubling bifurcations with increasing cantilever drive force that terminates in chaos. The threshold value of the drive force necessary to initiate bifurcation is shown to depend strongly on the cantilever setpoint and drive frequency, effective damping coefficient, nonlinearity of the cantilever-sample interaction force, and the displacement amplitude of cantilever oscillation. The model predicts the experimentally observed interruptions of the bifurcation cascade for cantilevers of sufficiently large stiffness. Operational factors leading to the loss of image quality in dynamic atomic force microscopy are addressed, and guidelines for optimizing scan stability are proposed using a quantitative analysis based on system dynamical parameters and choice of feedback loop parameter.

  17. The evolution of fabric with displacement in natural brittle faults

    NASA Astrophysics Data System (ADS)

    Mittempergher, S.; Di Toro, G.; Gratier, J.; Aretusini, S.; Boullier-Bertrand, A.

    2011-12-01

    In experiments performed at room temperature on gouges, a characteristic clast size distribution (CSD) is produced with increasing strain, and shear localization is documented to begin after few millimetres of sliding. But in natural faults active at depth in the crust, mechanical processes are associated with fluid-rock interactions, which might control the deformation and strength recovery. We aim to investigate the microstructural, geochemical and mineralogical evolution of low-displacement faults with increasing shear strain. The faults (cataclasite- and pseudotachylyte-bearing) are hosted in tonalite and were active at 9-11 km and 250-300°C. The samples were collected on a large glacier-polished outcrop, where major faults (accommodating up to 4300 mm of displacement) exploit pre-existing magmatic joints and are connected by a network of secondary fractures and faults (accommodating up to 500 mm of displacement) breaking intact tonalite. We performed optical and cathodoluminescence (CL) microscope, Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Rietveld X-Ray Powder Diffraction and microprobe chemical analysis in deformation zones of secondary faults with various offsets in order to evaluate the transfer of chemical species between dissolution zones and protected zones. Image analysis techniques were applied on SEM-BSE and optical microscope images to compute the CSD in samples, which experienced an increasing amount of strain. The secondary fractures are up to 5 mm thick. Within the first 20 mm of displacement, shear localizes along Y and R1 surfaces and a cataclastic foliation develops. The CSD evolves from a fractal dimension D of 1.3 in fractures without visible displacement to values above 2 after the first 500 mm of displacement. Chemical maps and CL images indicate that the foliation in cataclasite results from the rotation and fragmentation of clasts, with dissolution of quartz and passive concentration of Ti oxides

  18. Determination of the displacement energy of O, Si and Zr under electron beam irradiation

    SciTech Connect

    Edmondson, Philip D; Weber, William J; Namavar, Fereydoon; Zhang, Yanwen

    2012-01-01

    The response of nanocrystalline, stabilizer-free cubic zirconia thin films on a Si substrate to electron beam irradiation with energies of 4, 110 and 200 keV and fluences up to {approx}1.5 x 10{sup 22} e m{sup -2} has been studied to determine the displacement energies. The 110 and 200 keV irradiations were performed in situ using a transmission electron microscope; the 4 keV irradiations were performed ex situ using an electron gun. In all three irradiations, no structural modification of the zirconia was observed, despite the high fluxes and fluences. However the Si substrate on which the zirconia film was deposited was amorphized under the 200 keV electron irradiation. Examination of the electron-solid interactions reveals that the kinetic energy transfer from the 200 keV electrons to the silicon lattice is sufficient to cause atomic displacements, resulting in amorphization. The kinetic energy transfer from the 200 keV electrons to the oxygen sub-lattice of the zirconia may be sufficient to induce defect production, however, no evidence of defect production was observed. The displacement cross-section value of Zr was found to be {approx}400 times greater than that of O indicating that the O atoms are effectively screened from the electrons by the Zr atoms, and, therefore, the displacement of O is inefficient.

  19. Determination of the Displacement Energies of O, Si and Zr Under Electron Beam Irradiation

    SciTech Connect

    Edmondson, P. D.; Weber, William J.; Namavar, Fereydoon; Zhang, Yanwen

    2012-03-01

    The response of nanocrystalline, stabilizer-free cubic zirconia thin films on a Si substrate to electron beam irradiation with energies of 4, 110 and 200 keV and fluences up to ~1.5 x 10²²e m² has been studied to determine the displacement energies. The 110 and 200 keV irradiations were performed in situ using a transmission electron microscope; the 4 keV irradiations were performed ex situ using an electron gun. In all three irradiations, no structural modification of the zirconia was observed, despite the high fluxes and fluences. However the Si substrate on which the zirconia film was deposited was amorphized under the 200 keV electron irradiation. Examination of the electron–solid interactions reveals that the kinetic energy transfer from the 200 keV electrons to the silicon lattice is sufficient to cause atomic displacements, resulting in amorphization. The kinetic energy transfer from the 200 keV electrons to the oxygen sub-lattice of the zirconia may be sufficient to induce defect production, however, no evidence of defect production was observed. The displacement cross-section value of Zr was found to be ~400 times greater than that of O indicating that the O atoms are effectively screened from the electrons by the Zr atoms, and, therefore, the displacement of O is inefficient.

  20. A Molecular dynamics study of helium bubble stability during high-energy displacement cascades in α-iron

    SciTech Connect

    Pu, Jin; Yang, Li; Zu, Xiaotao; Gao, Fei

    2007-08-01

    The interactions of high-energy displacement cascades with helium bubbles in α-Fe are investigated using molecular dynamics simulations. Initial bubbles with the volumes of 212 and 636 Å3 are considered, and the helium-to-vacancy (He/V) ratio in the bubbles varies from 0.5 to 3. Primary knock-on atom (PKA) energy, Ep, is up to 40 keV. The results show that the change of nm-sized He bubbles due to displacement cascade does not depend much on the bubble size, but rather on the He/V ratio and the recoil energy. For the initial He/V ratio less than 1, the size of the bubbles decreases with increasing PKA energy, but the He/V ratio increases. However, for the initial He/V ratio of 3, the size of the bubbles increases, and the He/V ratio decreases with PKA energy. For the initial He/V ratio of 1, the ratio of the small bubble decreases slightly, but the ratio of the large bubble remains unchanged for lower PKA energy, and increases slightly for higher PKA energy. The reasons for these observed phenomena have been explained.

  1. Small-displacement measurements using high-order Hermite-Gauss modes

    SciTech Connect

    Sun, Hengxin; Liu, Kui; Liu, Zunlong; Guo, Pengliang; Zhang, Junxiang; Gao, Jiangrui

    2014-03-24

    We present a scheme for small-displacement measurements using high-order Hermite-Gauss modes and balanced homodyne detection. We demonstrate its use with experimental results of displacement measurements using fundamental transverse mode TEM{sub 00} and first order transverse mode TEM{sub 10} as signal modes. The results show a factor of 1.41 improvement in measurement precision with the TEM{sub 10} mode compared with that with the TEM{sub 00} mode. This scheme has potential applications in precision metrology, atomic force microscopy, and optical imaging.

  2. Health issues of internally displaced persons in Pakistan: preparation for disasters in future.

    PubMed

    Wasay, Mohammad; Mushtaq, Khalid

    2010-01-01

    Army action against terrorism in Pakistan led to the largest human migration in this century. About 3.4 million people (internally displaced persons, IDPs) were displaced. The authors visited all major camps and some houses in Mardan area and interviewed IDPs and doctors at these camps and areas to identify medical needs and current state of provision of medical care. This disaster largely represented displacement of millions of people (IDPs) including women and children to a new weather and environment in overcrowded refugee camps and houses. Influx of large number of displaced people created excessive burden for already deprived local health services. The medical issues and requirements for these IDPs living in camps were totally different from a disaster like earthquake. Global response to this disaster was slow and less effective. The need for a WHO coordination center for creating quick and urgent response for such kind of disasters in future is emphasized in this article. PMID:20496645

  3. Graphite filter atomizer in atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Katskov, Dmitri A.

    2007-09-01

    Graphite filter atomizers (GFA) for electrothermal atomic absorption spectrometry (ETAAS) show substantial advantages over commonly employed electrothermal vaporizers and atomizers, tube and platform furnaces, for direct determination of high and medium volatility elements in matrices associated with strong spectral and chemical interferences. Two factors provide lower limits of detection and shorter determination cycles with the GFA: the vaporization area in the GFA is separated from the absorption volume by a porous graphite partition; the sample is distributed over a large surface of a collector in the vaporization area. These factors convert the GFA into an efficient chemical reactor. The research concerning the GFA concept, technique and analytical methodology, carried out mainly in the author's laboratory in Russia and South Africa, is reviewed. Examples of analytical applications of the GFA in AAS for analysis of organic liquids and slurries, bio-samples and food products are given. Future prospects for the GFA are discussed in connection with analyses by fast multi-element AAS.

  4. Hirshfeld atom refinement

    PubMed Central

    Capelli, Silvia C.; Bürgi, Hans-Beat; Dittrich, Birger; Grabowsky, Simon; Jayatilaka, Dylan

    2014-01-01

    Hirshfeld atom refinement (HAR) is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly–l-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree–Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs) are freely refined without constraints or restraints – even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu’s), all other structural parameters agree within less than 2 csu’s. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules), the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å2 as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements – an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å. PMID:25295177

  5. Atomic supersymmetry

    NASA Technical Reports Server (NTRS)

    Kostelecky, V. Alan

    1993-01-01

    Atomic supersymmetry is a quantum-mechanical supersymmetry connecting the properties of different atoms and ions. A short description of some established results in the subject are provided and a few recent developments are discussed including the extension to parabolic coordinates and the calculation of Stark maps using supersymmetry-based models.

  6. Liquid atomization

    SciTech Connect

    Walzel, P. )

    1993-01-01

    A systematic review of different liquid atomizers is presented, accompanied by a discussion of various mechanisms of droplet formation in a gas atmosphere as a function of the liquid flow-regime and the geometry of the atomizer. Equations are presented for the calculation of the mean droplet-diameter. In many applications, details of the droplet size distribution are, also, important, e.g., approximate values of the breadth of the droplet formation are given. The efficiency of utilization of mechanical energy in droplet formation is indicated for the different types of atomizers. Atomization is used, in particular, for the following purposes: (1) atomization of fuels; (2) making granular products; (3) carrying out mass-transfer operations; and (4) coating of surfaces.

  7. Quantification of the vocal folds’ dynamic displacements

    NASA Astrophysics Data System (ADS)

    del Socorro Hernández-Montes, María; Muñoz, Silvino; De La Torre, Manuel; Flores, Mauricio; Pérez, Carlos; Mendoza-Santoyo, Fernando

    2016-05-01

    Fast dynamic data acquisition techniques are required to investigate the motional behavior of the vocal folds (VFs) when they are subjected to a steady air-flow through the trachea. High-speed digital holographic interferometry (DHI) is a non-invasive full-field-of-view technique that has proved its usefulness to study rapid and non-repetitive object movements. Hence it is an ideal technique used here to measure VF displacements and vibration patterns at 2000 fps. Analyses from a set of 200 displacement images showed that VFs’ vibration cycles are established along their width (y) and length (x). Furthermore, the maximum deformation for the right and left VFs’ area may be quantified from these images, which in itself represents an important result in the characterization of this structure. At a controlled air pressure, VF displacements fall within the range ~100-1740 nm, with a calculated precision and accuracy that yields a variation coefficient of 1.91%. High-speed acquisition of full-field images of VFs and their displacement quantification are on their own significant data in the study of their functional and physiological behavior since voice quality and production depend on how they vibrate, i.e. their displacement amplitude and frequency. Additionally, the use of high speed DHI avoids prolonged examinations and represents a significant scientific and technological alternative contribution in advancing the knowledge and working mechanisms of these tissues.

  8. Fingering phenomena during grain-grain displacement

    NASA Astrophysics Data System (ADS)

    Mello, Nathália M. P.; Paiva, Humberto A.; Combe, G.; Atman, A. P. F.

    2016-05-01

    Spontaneous formation of fingered patterns during the displacement of dense granular assemblies was experimentally reported few years ago, in a radial Hele-Shaw cell. Here, by means of discrete element simulations, we have recovered the experimental findings and extended the original study to explore the control parameters space. In particular, using assemblies of grains with different geometries (monodisperse, bidisperse, or polydisperse), we measured the macroscopic stress tensor in the samples in order to confirm some conjectures proposed in analogy with Saffman-Taylor viscous fingering phenomena for immiscible fluids. Considering an axial setup which allows to control the discharge of grains and to follow the trajectory and the pressure gradient along the displacing interface, we have applied the Darcy law for laminar flow in fluids in order to measure an "effective viscosity" for each assembly combination, in an attempt to mimic variation of the viscosity ratio between the injected/displaced fluids in the Saffman-Taylor experiment. The results corroborate the analogy with the viscous fluids displacement, with the bidisperse assembly corresponding to the less viscous geometry. But, differently to fluid case, granular fingers only develop for a specific combination of displaced/injected geometries, and we have demonstrated that it is always related with the formation of a force chain network along the finger direction.

  9. Ultra-Sensitive Magnetoresistive Displacement Sensing Device

    NASA Technical Reports Server (NTRS)

    Olivas, John D. (Inventor); Lairson, Bruce M. (Inventor); Ramesham, Rajeshuni (Inventor)

    2003-01-01

    An ultrasensitive displacement sensing device for use in accelerometers, pressure gauges, temperature transducers, and the like, comprises a sputter deposited, multilayer, magnetoresistive field sensor with a variable electrical resistance based on an imposed magnetic field. The device detects displacement by sensing changes in the local magnetic field about the magnetoresistive field sensor caused by the displacement of a hard magnetic film on a movable microstructure. The microstructure, which may be a cantilever, membrane, bridge, or other microelement, moves under the influence of an acceleration a known displacement predicted by the configuration and materials selected, and the resulting change in the electrical resistance of the MR sensor can be used to calculate the displacement. Using a micromachining approach, very thin silicon and silicon nitride membranes are fabricated in one preferred embodiment by means of anisotropic etching of silicon wafers. Other approaches include reactive ion etching of silicon on insulator (SOI), or Low Pressure Chemical Vapor Deposition of silicon nitride films over silicon substrates. The device is found to be improved with the use of giant magnetoresistive elements to detect changes in the local magnetic field.

  10. Spatial distribution measurement of atomic radiation with an astigmatism-corrected Czerny-Turner-type spectrometer in the Large Helical Device

    NASA Astrophysics Data System (ADS)

    Goto, Motoshi; Morita, Shigeru

    2006-10-01

    Emission lines in the visible/UV wavelength ranges are observed with 80 lines of sight which cover an entire poloidal cross section of the plasma in the Large Helical Device. The emitted light is received with optical fibers having 100μm diameter and is guided into a 1.33m Czerny-Turner-type spectrometer based on spherical mirrors for collimating and focusing. A charge-coupled device having 13.3×13.3mm2 area size is used as the detector and the spectra from all the lines of sight are recorded perpendicularly to the wavelength dispersion. The spectrometer is equipped with optics located in front of the entrance slit to correct the difference between the meridional and sagittal focal points, and thus the astigmatism, which otherwise causes severe cross talk between adjacent optical fiber images on the detector, is corrected. Consequently, simultaneous spectral measurement with 80 lines of sight is realized. The Zeeman splitting of a neutral helium line, λ667.8nm (2P1-3D1), which is caused by the magnetic field for plasma confinement, is measured with the spectrometer. Though the obtained line profile is in general a superposition of several components on the same line of sight, they can be separated according to their different splitting widths. The two-dimensional poloidal distribution of the helium line intensity is obtained with the help of a tomographic technique.

  11. Forced displacement and women's security in Colombia.

    PubMed

    Meertens, Donny

    2010-04-01

    In the protracted Colombian conflict, assistance to internally displaced persons has developed in the context of contradictory political processes. The Colombian government's launching of a transitional justice process in the midst of armed conflict has generated a complex situation displaying both conflict and post-conflict characteristics. The progressive Constitutional Court rulings on internal displacement, in particular the gender-sensitive Auto 092, constitute an attempt to bring together humanitarian interventions and transitional justice measures in a rights-based framework. However, the national government is reluctant to adopt them fully and local realities still hamper their integrated implementation. Displaced women, therefore, remain in an especially vulnerable position. This paper argues that gender-sensitive humanitarian interventions must take into account all of these complexities of scale and political process in order to make legal frameworks more effective at the local level. In these contexts, interventions should pay particular attention to strategies that contribute to transforming pre-existing gender regimes. PMID:20132270

  12. [Adaptation and mental-hygienic characteristics of internally displaced adolescents].

    PubMed

    Maksimović, Milos; Kocijancić, Radojka; Backović, Dusan; Ille, Tatjana; Paunović, Katarina

    2005-01-01

    The change in socio-economic status, drastic decrease in living standards, war, and the introduction of sanctions to our country were complicated in addition by a large number of internally displaced people from Kosovo, which culminated with the 1999 NATO bombing. The aim of this investigation was to estimate the influence of internal displacement on the adaptation and mental health of adolescents. The investigation was conducted on 238 adolescents, comprising a control group of 206 adolescents from Belgrade and 32 internally displaced adolescents from Kosovo. A specific questionnaire regarding habits, behaviour, and psychosomatic state was used, as well as the Cornell Medical Index and the Eysenck Personality Questionnaire. Internally displaced adolescents from Kosovo exhibited greater difficulties in adapting and had worse school records than adolescents from Belgrade, one year after the change in their location. Immediately after the NATO bombing, both groups reacted in the same way: they often talked about the events they had survived, they were afraid of the sounds of alarm sirens and of aeroplanes, and in addition had similar dreams (no statistical variation between the groups). Emotional disturbances, one year after the bombing, were not observed in 40.6% of adolescents from Kosovo, compared to the figure of 74.8% for adolescents from Belgrade. Adolescents from Belgrade consumed alcohol significantly more often: 75.7% compared to 56.3% for adolescents from Kosovo. In addition, 20.4% of adolescents from Belgrade consumed psychoactive substances compared to 6.3% of adolescents from Kosovo. There was no significant difference between the examined groups in the total scores on the scale for neuroticism. All in all, the girls from both examined groups displayed neurotic tendencies more frequently than the boys. PMID:16392285

  13. Displacement sensors using soft magnetostrictive alloys

    NASA Astrophysics Data System (ADS)

    Hristoforou, E.; Reilly, R. E.

    1994-09-01

    We report results on the response of a family of displacement sensors, which are based on the magentostrictive delay line (MDL) technique, using current conductors orthogonal to the MDL. Such sensing technique is based on the change of the magnetic circuit at the acoustic stress point of origin due to the displacement of a soft magnetic material above it. Integrated arrays of sensors can be obtained due to the acoustic delay line technique and they can be used as tactile arrays, digitizers or devices for medical applications (gait analysis etc.), while absence of hysteresis and low cost of manufacturing make them competent in this sector of sensor market.

  14. Displacement sensors using soft magnetostrictive alloys

    SciTech Connect

    Hristoforou, E. . Inst. of Material Science); Reilly, R.E. . Electronic and Electrical Engineering Dept.)

    1994-09-01

    The authors report results on the response of a family of displacement sensors, which are based on the magnetostrictive delay line (MDL) technique, using current conductor orthogonal to the MDL. Such sensing technique is based on the change of the magnetic circuit and the acoustic stress point of origin due to the displacement of a soft magnetic material above it. Integrated arrays of sensors can be obtained due to the acoustic delay line technique and they can be used as tactile arrays, digitizers or devices for medical application (gait analysis etc.), while absence of hysteresis and low cost of manufacturing make them competent in this sector of sensor market.

  15. Fibre optic distributed differential displacement sensor

    NASA Astrophysics Data System (ADS)

    Wylie, Michael T. V.; Brown, Anthony W.; Colpitts, Bruce G.

    2011-05-01

    A Fibre Optic Distributed Differential Displacement Sensor is modelled and experimentally verified to determine shape. Created using a steel tape, 9/125 μm single mode fibre, and adhesive, the FODDDS can be used to determine shape or displacement of any object to which it is bonded. A circular shape is examined, and a radius of curvature comparison yields an error of 2%. The sensitivity of the FODDDS, for the substrate thickness used in this experiment, is shown to be 1.27 mm between adjacent data points, which corresponds to a radius of curvature of 103 m.

  16. Maxillary tooth displacement in the infratemporal fossa

    PubMed Central

    Roshanghias, Korosh; Peisker, Andre; Zieron, Jörg Olaf

    2016-01-01

    Wisdom tooth operations are sometimes accompanied by complications. This case report shows complications during upper jaw third molar removal. Expectable problems during oral surgery should be planned to be solved in advance. Displacement of the third molar during oral surgeries as a considerable complication is rarely discussed scientifically. A good design of flap, adequate power for extraction, and clear view on the surgical field are crucial. Three-dimensional radiographic diagnostics in terms of cone beam computed tomography is helpful after tooth displacement into the infratemporal fossa.

  17. Maxillary tooth displacement in the infratemporal fossa.

    PubMed

    Roshanghias, Korosh; Peisker, Andre; Zieron, Jörg Olaf

    2016-01-01

    Wisdom tooth operations are sometimes accompanied by complications. This case report shows complications during upper jaw third molar removal. Expectable problems during oral surgery should be planned to be solved in advance. Displacement of the third molar during oral surgeries as a considerable complication is rarely discussed scientifically. A good design of flap, adequate power for extraction, and clear view on the surgical field are crucial. Three-dimensional radiographic diagnostics in terms of cone beam computed tomography is helpful after tooth displacement into the infratemporal fossa. PMID:27605997

  18. Long-lived staus and displaced leptons at the LHC

    NASA Astrophysics Data System (ADS)

    Evans, Jared A.; Shelton, Jessie

    2016-04-01

    As the majority of LHC searches are focused on prompt signatures, specific long-lived particles have the potential to be overlooked by the otherwise systematic new physics programs at ATLAS and CMS. While in many cases long-lived superparticles are now stringently constrained by existing exotic searches, we point out that the highly motivated model of gauge mediation with staus as the next-to-lightest superparticle (NLSP) is relatively far less tested. We recast LHC searches for heavy stable charged particles, disappearing tracks, and opposite-flavor leptons with large impact parameters to assess current constraints on a variety of spectra that contain an NLSP stau, and find that portions of the parameter space motivated by naturalness are still experimentally unexplored. We additionally note a gap in the current experimental search program: same-flavor leptons with large impact parameters evade the suite of existing searches for long-lived objects. This gap is especially noteworthy as vetoes on displaced leptons in prompt new physics searches could be systematically discarding such events. We discuss several motivated models that can exhibit same-flavor displaced leptons: gauge mediation with co-NLSP sleptons, extended gauge mediation, R-parity violation, and lepton-flavored dark matter that freezes in during a matter-dominated era of the early universe. To address this gap, we propose a straightforward extension of the CMS search for leptons with large impact parameters, and project sensitivity to these scenarios at 13 TeV. Throughout this analysis, we highlight several methods whereby LHC searches for exotic long-lived objects could potentially improve their sensitivity to the displaced leptons originating from gauge mediation and beyond.

  19. Displacement Patterns of Blunt Rib Fractures and Their Relationship to Thoracic Coinjuries: Minimal Displacements Count.

    PubMed

    Bugaev, Nikolay; Breeze, Janis L; Alhazmi, Majid; Anbari, Hassan S; Arabian, Sandra S; Rabinovici, Reuven

    2016-03-01

    Displacement patterns of rib fractures (RF) and their association with thoracic coinjuries and outcomes are unknown. This is a retrospective review of adult patients with blunt closed RF who underwent chest CT at a Level I trauma center (2007-2012). Displacement patterns of RF were compared among the three-dimensional planes using CT images. An analysis of receiver operating characteristic (ROC) curves was performed to identify displacements in each plane most strongly associated with chest coinjuries. Univariate analysis was used to find association of displaced RF with hospital course and outcome. There were 1127 RF (245 patients, most in ribs 3-9, 45 per cent displaced). Axial displacement was the most common, with odds ratios 7.20 and 2.13 compared with cranio-caudal, and impaction-separation (along rib axis) movement, respectively. Axial displacement thresholds performed well with hemothorax (2.8 mm, ROC = 0.74), pneumothorax (2.6 mm, ROC = 0.70), hemopneumothorax (3.1 mm, ROC = 0.77), flail chest (3.4 mm, ROC = 0.80), and chest tube placement (2.8 mm, ROC = 0.75). RF displacement was associated with increased days on mechanical ventilation and hospital length of stay. In conclusion, even minimal RF displacement is associated with increased risk of chest coinjuries and chest tube placement, and displacements correlated with increased days on mechanical ventilation and hospital length of stay. Future studies are required to investigate these associations, especially in relationship to the indications for rib plating. PMID:27099054

  20. Wireless Power Transfer during Displacement Using Electromagnetic Coupling in Resonance

    NASA Astrophysics Data System (ADS)

    Imura, Takehiro; Okabe, Hiroyuki; Uchida, Toshiyuki; Hori, Yoichi

    This paper proposes a novel way for achieving wireless power transfer from a transmitting antenna to a receiving antenna. This technique is suitable for charging electric vehicles (EVs) because the proposed antennas can transfer power wirelessly with high efficiencies when the antennas are displaced and have large air gaps. This technique utilizes near-field antennas at resonance; however, this technique is still being perfected. This paper describes this techniques' analysis, its results, as well as the possible antennas that are suitable for EVs.

  1. Strain-displacement relations for strain engineering in single-layer 2d materials

    NASA Astrophysics Data System (ADS)

    Midtvedt, Daniel; Lewenkopf, Caio H.; Croy, Alexander

    2016-03-01

    We investigate the electromechanical coupling in single-layer 2d materials. For non-Bravais lattices, we find important corrections to the standard macroscopic strain-microscopic atomic-displacement theory. We put forward a general and systematic approach to calculate strain-displacement relations for several classes of 2d materials. We apply our findings to graphene as a study case, by combining a tight binding and a valence force-field model to calculate electronic and mechanical properties of graphene nanoribbons under strain. The results show good agreement with the predictions of the Dirac equation coupled to continuum mechanics. For this long wave-limit effective theory, we find that the strain-displacement relations lead to a renormalization correction to the strain-induced pseudo-magnetic fields. A similar renormalization is found for the strain-induced band-gap of black phosphorous. Implications for nanomechanical properties and electromechanical coupling in 2d materials are discussed.

  2. An IPMC microgripper with integrated actuator and sensing for constant finger-tip displacement

    NASA Astrophysics Data System (ADS)

    Gonzalez, Carlos; Lumia, Ron

    2015-05-01

    Ionic polymer metal composite (IPMC) is a type of smart material that has gained the interest of many researchers due to its ability to achieve large displacements under small input voltages, usually less than 2.5 V. This has motivated the use of these materials in microsystems and systems in the millimeter scale, such as microgrippers. However, few of the control techniques developed thus far have considered the feasibility of using IPMCs in closed loop systems without the need of oversized external sensors. This paper presents a control scheme for a two-finger IPMC microgripper that accomplishes constant finger-tip displacements without external sensors. This scheme generates a displacement-dependent, time varying reference signal to obtain constant finger-tip displacements applied by a separate actuated IPMC. This actuator uses a PID controller tuned with a model-free approach, and is gain scheduled to span up to 1 mm finger-tip displacements. The microgripper achieves zero steady state error for finger-tip displacements on the tuned values of the PID controller. The gain scheduled PID controller is tested and results show zero steady state error to 0.25 mm displacements, and 15 and 20% steady state error when referenced to deflection of 0.45 and 0.75 mm, respectively. This shows that there is great confidence and validity of the control scheme, especially when tracking small reference deflections.

  3. Design and test of a micro-displacement actuator based on giant magnetostrictive material

    NASA Astrophysics Data System (ADS)

    Shao, Liang; Yang, Dehua; Yang, Bintang; Chen, Kunxin

    2009-07-01

    To meet the performance requirements of co-focusing and co-phasing of segmented mirror active optics (SMAO) in modern astronomical telescope, micro-displacement actuators with nanometer resolution and millimeter stroke are necessary. The design and test of a micro-displacement actuator based on giant magnetostrictive material is present in this paper. The actuator's main components, such as giant magnetostrictive drive core, displacement pantograph mechanism and output guide mechanism, are discussed in detailed. The giant magnetostrictive drive mechanism generally may offer nanometer resolution and micron stroke. A displacement/stroke pantograph mechanism is designed with absolutely sealed flexible hydraulic structure (ASFHS) to enlarge the stroke. In addition, a secondary giant magnetostrictive drive mechanism is integrated to serve final resolution of final displacement output. In view of flexure exhibiting excellent mechanical properties free of friction, clearance and lubrication, a flexure guide mechanism with the capacity of excellent lateral load is designed to fulfill linear displacement output steadily. The sub-systems like the giant magnetostrictive drive core and displacement pantograph mechanism have been tested before integration of the whole actuator. The final test of the actuator is carried out with dual frequency laser interferometer at lab. Besides, to meet technical requirements of future extremely large telescope, further development issues mainly related to application practice of the actuator is discussed at the end.

  4. Acting Atoms.

    ERIC Educational Resources Information Center

    Farin, Susan Archie

    1997-01-01

    Describes a fun game in which students act as electrons, protons, and neutrons. This activity is designed to help students develop a concrete understanding of the abstract concept of atomic structure. (DKM)

  5. Kinetic Atom.

    ERIC Educational Resources Information Center

    Wilson, David B.

    1981-01-01

    Surveys the research of scientists like Joule, Kelvin, Maxwell, Clausius, and Boltzmann as it comments on the basic conceptual issues involved in the development of a more precise kinetic theory and the idea of a kinetic atom. (Author/SK)

  6. Newton's Atom

    NASA Astrophysics Data System (ADS)

    Chaney, Andrea; Espinosa, James; Espinosa, James

    2006-10-01

    At the turn of the twentieth century, physicists and chemists were developing atomic models. Some of the phenomena that they had to explain were the periodic table, the stability of the atom, and the emission spectra. Niels Bohr is known as making the first modern picture that accounted for these. Unknown to much of the physics community is the work of Walter Ritz. His model explained more emission spectra and predates Bohr's work. We will fit several spectra using Ritz's magnetic model for the atom. The problems of stability and chemical periodicity will be shown to be challenges that this model has difficulty solving, but we will present some potentially useful adaptations to the Ritzian atom that can account for them.

  7. RECOVERY OF METAL USING ALUMINUM DISPLACEMENT

    EPA Science Inventory

    The removal of typical metals (Cu, Pb, Sn, Ni) from printed circuit and metal finishing waste streams was evaluated using displacement with aluminum. he metal is recovered as non-hazardous metal particles and can be recycled by smelting. n acceptable aluminum metal configuration ...

  8. A Personal Appearance Program for Displaced Homemakers.

    ERIC Educational Resources Information Center

    Fiore, Ann Marie; De Long, Marilyn Revell

    1990-01-01

    A career counseling program evaluated the self-esteem of 28 displaced homemakers, then presented 3 sessions on the importance of personal appearance in hiring practices, wardrobe management, nonverbal communication, professional image, and self-concept. Analysis of participant evaluations indicated improved levels of control and confidence and…

  9. Measurement of gas quantities by liquid displacement.

    NASA Technical Reports Server (NTRS)

    Christian, J. D.

    1973-01-01

    Derivation of equations relating the different variables involved in gas quantity measurements by liquid displacement from a Mariotte flask. The results are used to elucidate design criteria and operational procedures required for the realization of various degrees of desired accuracy down to 0.01%.

  10. The Income Losses of Displaced Workers

    ERIC Educational Resources Information Center

    Hijzen, Alexander; Upward, Richard; Wright, Peter W.

    2010-01-01

    We use a new, matched worker-firm dataset for the United Kingdom to estimate the income loss resulting from firm closure and mass layoffs. We track workers for up to nine years after the displacement event, and the availability of predisplacement characteristics allows us to implement difference-in-differences estimators using propensity score…

  11. Job Displacement and the Rural Worker.

    ERIC Educational Resources Information Center

    Podgursky, Michael

    High rates of unemployment in rural areas poses questions as what education can do with the problem. This report examines the effects of rural American economies as they grow away from agriculture and toward dependence on manufacturing and service industries. Using data from the federal Bureau of Labor Statistics' Displaced Worker Survey, the…

  12. RECOVERY OF METALS USING ALUMINUM DISPLACEMENT

    EPA Science Inventory

    The removal of typical metals (Cu, Pb, Sn, Ni) from printed circuit and metal finishing waste streams was evaluated using displacement with aluminum. he metal is recovered as non-hazardous metal particles and can be recycled by smelting. n acceptable aluminum metal configuration ...

  13. Developing Programs for (Displaced) Homemakers in Transition.

    ERIC Educational Resources Information Center

    Arkansas Univ., Fayetteville. Dept. of Vocational Education.

    Two projects (Preparation of Vocational Personnel for Assessing Needs and Improving Employability of Selected Homemakers, November 1978 through June 1979, and Developing and Providing Multipurpose Employability Services and a Supportive Environment for Displaced Homemakers and Related Groups, February 1979 through June 1980) were conducted to…

  14. Ko Displacement Theory for Structural Shape Predictions

    NASA Technical Reports Server (NTRS)

    Ko, William L.

    2010-01-01

    The development of the Ko displacement theory for predictions of structure deformed shapes was motivated in 2003 by the Helios flying wing, which had a 247-ft (75-m) wing span with wingtip deflections reaching 40 ft (12 m). The Helios flying wing failed in midair in June 2003, creating the need to develop new technology to predict in-flight deformed shapes of unmanned aircraft wings for visual display before the ground-based pilots. Any types of strain sensors installed on a structure can only sense the surface strains, but are incapable to sense the overall deformed shapes of structures. After the invention of the Ko displacement theory, predictions of structure deformed shapes could be achieved by feeding the measured surface strains into the Ko displacement transfer functions for the calculations of out-of-plane deflections and cross sectional rotations at multiple locations for mapping out overall deformed shapes of the structures. The new Ko displacement theory combined with a strain-sensing system thus created a revolutionary new structure- shape-sensing technology.

  15. Retraining Displaced Workers--Barriers and Facilitators.

    ERIC Educational Resources Information Center

    Wolansky, William D.

    Although plant closings and layoffs have been happening for a long time, today's recessions, major changes in the structure of the economy, and a tight job market have combined to make plant closings a more serious problem. Workers are faced with unemployment from both traditional labor-displacing changes, such as the increasing use of robotics;…

  16. Displacement Damage in Bipolar Linear Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Rax, B. G.; Johnston, A. H.; Miyahira, T.

    2000-01-01

    Although many different processes can be used to manufacture linear integrated circuits, the process that is used for most circuits is optimized for high voltage -- a total power supply voltage of about 40 V -- and low cost. This process, which has changed little during the last twenty years, uses lateral and substrate p-n-p transistors. These p-n-p transistors have very wide base regions, increasing their sensitivity to displacement damage from electrons and protons. Although displacement damage effects can be easily treated for individual transistors, the net effect on linear circuits can be far more complex because circuit operation often depends on the interaction of several internal transistors. Note also that some circuits are made with more advanced processes with much narrower base widths. Devices fabricated with these newer processes are not expected to be significantly affected by displacement damage for proton fluences below 1 x 10(exp 12) p/sq cm. This paper discusses displacement damage in linear integrated circuits with more complex failure modes than those exhibited by simpler devices, such as the LM111 comparator, where the dominant response mode is gain degradation of the input transistor. Some circuits fail catastrophically at much lower equivalent total dose levels compared to tests with gamma rays. The device works satisfactorily up to nearly 1 Mrad(Si) when it is irradiated with gamma rays, but fails catastrophically between 50 and 70 krad(Si) when it is irradiated with protons.

  17. Polymer displacement/shielding in protein chromatography.

    PubMed

    Kumar, A; Galaev, I Y; Mattiasson, B

    2000-05-12

    An overview of different applications of polymer interactions with ion-exchange and dye-affinity chromatographic matrices is presented here. The strength of interaction between the ligand and the polymer plays a crucial role in deciding the mode of chromatographic application. Charged, non-ionic and thermosensitive polymers such as poly(ethylene imine), poly(N-vinyl pyrrolidone) and poly(vinyl caprolactam) respectively, show different degrees of interaction with the dye molecules in dye ligand chromatography. Polymers, with their ability of multipoint and hence strong attachment to the chromatographic matrices, were used as efficient displacers in displacement chromatography. The polymer displacement resulted in better recoveries and sharper elution profiles than traditional salt elutions. The globule-coil transition of the thermosensitive reversible soluble-insoluble polymer, poly(vinyl caprolactam), can be exploited in dye-affinity columns for the temperature induced displacement of the bound protein. In another situation, prior to the column chromatography of crude protein extract, polymers formed complexes with the dye matrix and "shielded" the column. The polymer shielding decreased the nonspecific interactions without affecting the specific interactions of the target protein to the dye matrix. PMID:10872581

  18. Careers for Homemakers (A Displaced Homemakers Program).

    ERIC Educational Resources Information Center

    Hanks, Marlene

    St. Louis Community College's Careers for Homemakers program is a vocational counseling program designed to help displaced homemakers enter the job market for the first time or after a significant absence. The program's goal is to place participants, chosen according to academic or economic disadvantaged eligibility, in jobs consistent with their…

  19. Opening Doors for the Displaced Worker.

    ERIC Educational Resources Information Center

    Moore, Martha Norris

    2000-01-01

    Describes the many benefits now available to laid-off and displaced textile and apparel-related workers through the North American Free Trade Agreement's Transitional Adjustment Allowance (NAFTA-TAA), which allows them to attend college for the first time. Examines the effectiveness of the TAA program and concludes that there is room for "cautious…

  20. YUP.SCX: Coaxing Atomic Models into Medium Resolution Electron Density Maps

    PubMed Central

    Tan, Robert K.-Z.; Devkota, Batsal; Harvey, Stephen C.

    2008-01-01

    The structures of large macromolecular complexes in different functional states can be determined by cryo-electron microscopy, which yields electron density maps of low to intermediate resolutions. The maps can be combined with high-resolution atomic structures of components of the complex, to produce a model for the complex that is more accurate than the formal resolution of the map. To this end, methods have been developed to dock atomic models into density maps rigidly or flexibly, and to refine a docked model so as to optimize the fit of the atomic model into the map. We have developed a new refinement method called YUP.SCX. The electron density map is converted into a component of the potential energy function to which terms for stereochemical restraints and volume exclusion are added. The potential energy function is then minimized (using simulated annealing) to yield a stereochemically-restrained atomic structure that fits into the electron density map optimally. We used this procedure to construct an atomic model of the 70S ribosome in the pre-accommodation state. Although some atoms are displaced by as much as 33 Å, they divide themselves into nearly rigid fragments along natural boundaries with smooth transitions between the fragments. PMID:18572416