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1

Luttinger Model and Luttinger Liquids  

NASA Astrophysics Data System (ADS)

The Luttinger model owes its solvability to a number of peculiar features, like its linear relativistic dispersion relation, which are absent in more realistic fermionic systems. Nevertheless according to the Luttinger liquid conjecture a number of relations between exponents and other physical quantities, which are valid in the Luttinger model, are believed to be true in a wide class of systems, including tight binding or jellium one-dimensional fermionic systems. Recently a rigorous proof of several Luttinger liquid relations in nonsolvable models has been achieved; it is based on exact Renormalization Group methods coming from Constructive Quantum Field Theory and its main steps will be reviewed below.

Mastropietro, Vieri

2014-10-01

2

condmat/9711204 Properties of a Luttinger Liquid with Boundaries  

E-print Network

, much in the same way as the normal state of 3D interacting electrons is patterned on the free Fermi gas, the ability to manufacture true 1D quantum wires 5;6 , as well as the development of high excitations of the fractional quantum Hall effect can be described in terms of a chiral Luttinger liquid 8

Eggert, Sebastian

3

Detection of entanglement by helical Luttinger liquids  

NASA Astrophysics Data System (ADS)

A Cooper-pair or electron-hole splitter is a device capable of spatially separating entangled fermionic quasiparticles into mesoscopic solid-state systems such as quantum dots or quantum wires. We theoretically study such a splitter based on a pair of helical Luttinger liquids, which arise naturally at the edges of a quantum spin Hall insulator. Equipping each helical liquid with a beam splitter, current-current cross correlations can be used to construct a Bell inequality whose violation would indicate nonlocal orbital entanglement of the injected electrons and/or holes. Due to the Luttinger-liquid correlations, however, the entanglement is suppressed depending on ambient temperature and voltage bias.

Sato, Koji; Tserkovnyak, Yaroslav

2014-07-01

4

Dimensional crossover from Fermi to Luttinger liquid  

SciTech Connect

We analyze the low energy behavior of interacting fermions in continuous dimensions [ital d] between one and two. It is shown that Fermi liquid fixed points are stable with respect to residual scattering of quasiparticles by regular interactions in any dimension above one, while the structure of corrections to quasiparticle behavior changes drastically below two dimensions. The crossover from Luttinger liquid behavior in 1D to Fermi liquid behavior in higher dimensions is described by a tomographic Luttinger model with effective interactions approaching zero with a power [ital d][minus]1 of the distance from the Fermi surface.

Castellani, C.; Di Castro, C.; Metzner, W. (Dipartimento di Fisica, Universita La Sapienza'', piazzale A. Moro 2, 00185 Roma (Italy))

1994-01-17

5

COVER IMAGE The TomonagaLuttinger liquid  

E-print Network

COVER IMAGE The Tomonaga­Luttinger liquid model is the leading candidate for describing 1D metallic conductors at low temperature. Yet, experimental evidence that it is valid is sketchy. Scanning tunnelling to sensitively detect small deformations of the graphene sheet. Article p810 Spin liquids are states of matter

Loss, Daniel

6

Long Time Correlations of Nonlinear Luttinger Liquids  

NASA Astrophysics Data System (ADS)

An overview is given of the limitations of Luttinger liquid theory in describing the real time equilibrium dynamics of critical one-dimensional systems with nonlinear dispersion relation. After exposing the singularities of perturbation theory in band curvature effects that break the Lorentz invariance of the Tomonaga-Luttinger model, the origin of high frequency oscillations in the long time behaviour of correlation functions is discussed. The notion that correlations decay exponentially at finite temperature is challenged by the effects of diffusion in the density-density correlation due to umklapp scattering in lattice models.

Pereira, Rodrigo G.

2014-10-01

7

The Luttinger Liquid and Integrable Models  

NASA Astrophysics Data System (ADS)

Many fundamental one-dimensional lattice models such as the Heisenberg or the Hubbard model are integrable. For these microscopic models, parameters in the Luttinger liquid theory can often be fixed and parameter-free results at low energies for many physical quantities such as dynamical correlation functions obtained where exact results are still out of reach. Quantum integrable models thus provide an important testing ground for low-energy Luttinger liquid physics. They are, furthermore, also very interesting in their own right and show, for example, peculiar transport and thermalization properties. The consequences of the conservation laws leading to integrability for the structure of the low-energy effective theory have, however, not fully been explored yet. I will discuss the connection between integrability and Luttinger liquid theory here, using the anisotropic Heisenberg model as an example. In particular, I will review the methods which allow to fix free parameters in the Luttinger model with the help of the Bethe ansatz solution. As applications, parameter-free results for the susceptibility in the presence of nonmagnetic impurities, for spin transport, and for the spin-lattice relaxation rate are discussed.

Sirker, J.

2014-10-01

8

Full counting statistics of Luttinger liquid conductor  

Microsoft Academic Search

Non-equilibrium bosonization technique is used to study current fluctuations\\u000aof interacting electrons in a single-channel quantum wire representing a\\u000aLuttinger liquid (LL) conductor. An exact expression for the full counting\\u000astatistics of the transmitted charge is derived. It is given by Fredholm\\u000adeterminant of the counting operator with a time dependent scattering phase.\\u000aThe result has a form of counting

D. B. Gutman; Yuval Gefen; A. D. Mirlin

2010-01-01

9

Holographic Non-Fermi Liquids and the Luttinger Theorem  

E-print Network

We show that the Luttinger theorem, a robust feature of Fermi liquids, can be violated in non-Fermi liquids. We compute non-Fermi liquid Green functions using duality to black holes and find that the volume of the Fermi surface depends exponentially on the scaling dimension, which is a measure of the coupling. This demonstrates that Luttinger's theorem does not extend to non-Fermi liquids. We comment on possible experimental signatures.

Finn Larsen; Greg van Anders

2010-06-09

10

Helical Luttinger Liquids and Three Dimensional Black Holes  

E-print Network

Cold interacting fermions in two dimensions form exactly solvable Luttinger liquids, whose characteristic scaling exponents differ from those of conventional Fermi liquids. We use the AdS/CFT correspondence to discuss an equivalence between a class of helical, strongly coupled Luttinger liquids and fermions propagating in the background of a 3D black hole. The microscopic Lagrangian is explicitly known and the construction is fully embeddable in string theory. The retarded Green function at low temperature and energy arises from the geometry very near the black hole horizon. This structure is universal for all cold, charged liquids with a dual description in gravity.

Vijay Balasubramanian; Iñaki García-Etxebarria; Finn Larsen; Joan Simón

2010-12-20

11

Relaxation in Luttinger liquids: Bose-Fermi duality  

NASA Astrophysics Data System (ADS)

We explore the lifetime of excitations in a dispersive Luttinger liquid. We perform a bosonization supplemented by a sequence of unitary transformations that allows us to treat the problem in terms of weakly interacting quasiparticles. The relaxation described by the resulting Hamiltonian is analyzed by bosonic and (after a refermionization) by fermionic perturbation theory. We show that the fermionic and bosonic formulations of the problem exhibit a remarkable strong-weak coupling duality. Specifically, the fermionic theory is characterized by a dimensionless coupling constant ? =m*l2T and the bosonic theory by ?-1, where 1/m* and l characterize the curvature of the fermionic and bosonic spectra, respectively, and T is the temperature.

Protopopov, I. V.; Gutman, D. B.; Mirlin, A. D.

2014-09-01

12

Spin-charge separation in transport through Luttinger liquid rings S. Friederich  

E-print Network

electron systems Luttinger liquids affect the transport properties of ringlike conductors. The LuttingerSpin-charge separation in transport through Luttinger liquid rings S. Friederich Institut für liquid ring is coupled to two noninteracting leads and pierced by a magnetic flux. We study the flux

13

Energy transport in Heisenberg chains beyond the Luttinger liquid paradigm  

NASA Astrophysics Data System (ADS)

We study the energy transport between two interacting spin chains which are initially separated, held at different temperatures, and subsequently put in contact. We consider the spin-1/2 XXZ model in the gapless regime and exploit its integrability properties to formulate an analytical ansatz for the nonequilibrium steady state even at temperatures where the low-energy Luttinger liquid description is not accurate. We apply our method to compute the steady energy current and benchmark it both with the known low-energy limit and at higher temperatures with numerical simulations. We find an excellent agreement even at high temperatures, where the Luttinger liquid prediction is shown to fail.

De Luca, Andrea; Viti, Jacopo; Mazza, Leonardo; Rossini, Davide

2014-10-01

14

Full Counting Statistics of a Luttinger Liquid Conductor  

Microsoft Academic Search

Nonequilibrium bosonization technique is used to study current fluctuations of interacting electrons in a single-channel quantum wire representing a Luttinger liquid (LL) conductor. An exact expression for the time resolved full counting statistics of the transmitted charge is derived. It is given by the Fredholm determinant of the counting operator with a time-dependent scattering phase. The result has a form

D. B. Gutman; Yuval Gefen; A. D. Mirlin

2010-01-01

15

Tunneling between a topological superconductor and a Luttinger liquid  

NASA Astrophysics Data System (ADS)

We study the quantum point contact between the topological superconductor and the helical Luttinger liquid. The effects of the electron-electron interactions in the helical Luttinger liquid on the low-energy physics of this system are analyzed by the renormalization group. Among the various couplings at the point contact which arises from the tunneling via the Majorana edge channel, the induced backscattering in the helical Luttinger liquid is the most relevant for repulsive interactions. Hence, at low temperatures, the helical Luttinger liquid is effectively cut into two separated half wires. As a result, the low-temperature physics is described by a fixed point consisting of two leads coupled to the topological superconductor, and the electrical transport properties through the point contact at low temperature and low bias are dominated by the tunneling via the Majorana edge channel. We compute the temperature dependence of the zero-bias tunneling conductance and study the full counting statistics for the tunneling current at zero temperature.

Lee, Yu-Wen; Lee, Yu-Li

2014-03-01

16

a Luttinger Liquid Core Inside HELIUM-4 Filled Nanopores  

NASA Astrophysics Data System (ADS)

As helium-4 is cooled below 2.17 K it undergoes a phase transition to a fundamentally quantum mechanical state of matter known as a superfluid which supports flow without viscosity. This type of dissipationless transport can be observed by forcing helium to travel through a narrow constriction that the normal liquid could not penetrate. Recent experiments have highlighted the feasibility of fabricating smooth pores with nanometer radii, that approach the truly one-dimensional limit where it is believed that a system of bosons (like helium-4) may have startlingly different behavior than in three dimensions. The one-dimensional system is predicted to have a linear hydrodynamic description known as Luttinger liquid (LL) theory, where no type of long range order can be sustained. In the limit where the pore radius is small, LL theory would predict that helium inside the channel behaves as a sort of quasi-supersolid with all correlations decaying as power-law functions of distance at zero temperature. We have performed large scale quantum Monte Carlo simulations of helium-4 inside nanopores of varying radii at low temperature with realistic helium.helium and helium-pore interactions. The results indicate that helium inside the nanopore forms concentric cylindrical shells surrounding a core that can be described via LL theory and provides insights into the exciting possibility of the experimental detection of this intriguing low-dimensional state of matter.

Del Maestro, Adrian

2014-10-01

17

Fractionalized wave packets from an artificial Tomonaga-Luttinger liquid  

NASA Astrophysics Data System (ADS)

The model of interacting fermion systems in one dimension known as a Tomonaga-Luttinger liquid (TLL) provides a simple and exactly solvable theoretical framework that predicts various intriguing physical properties. Evidence of a TLL has been observed as power-law behaviour in electronic transport on various types of one-dimensional conductor. However, these measurements, which rely on d.c. transport involving electron tunneling processes, cannot identify the long-awaited hallmark of charge fractionalization, in which an injection of elementary charge e from a non-interacting lead is divided into the non-trivial effective charge e* and the remainder, e-e* (refs 6, 7, 8). Here, we report time-resolved transport measurements on an artificial TLL composed of coupled integer quantum Hall edge channels, in which we successfully identify single charge fractionalization processes. A wave packet of charge q incident from a non-interacting region breaks up into several fractionalized charge wave packets at the edges of the artificial TLL, from which transport eigenmodes can be evaluated directly. These results are informative for elucidating the nature of TLLs and low-energy excitations in the edge channels.

Kamata, H.; Kumada, N.; Hashisaka, M.; Muraki, K.; Fujisawa, T.

2014-03-01

18

Tunable Nonequilibrium Luttinger Liquid Based on Counterpropagating Edge Channels  

NASA Astrophysics Data System (ADS)

We investigate the energy transfer between counterpropagating quantum Hall edge channels (ECs) in a two-dimensional electron system at a filling factor of ? =1. The ECs are separated by a thin impenetrable potential barrier and Coulomb coupled, thereby constituting a quasi-one-dimensional analogue of a spinless Luttinger liquid (LL). We drive one, say hot, EC far from thermal equilibrium and measure the energy transfer rate P into the second, cold, EC using a quantum point contact as a bolometer. The dependence of P on the drive bias indicates a breakdown of the momentum conservation, whereas P is almost independent of the length of the region where the ECs interact. Interpreting our results in terms of plasmons (collective density excitations), we find that the energy transfer between the ECs occurs via plasmon backscattering at the boundaries of the LL. The backscattering probability is determined by the LL interaction parameter and can be tuned by changing the width of the electrostatic potential barrier between the ECs.

Prokudina, M. G.; Ludwig, S.; Pellegrini, V.; Sorba, L.; Biasiol, G.; Khrapai, V. S.

2014-05-01

19

Magnetotunneling as a Probe of Luttinger-Liquid Behavior  

NASA Astrophysics Data System (ADS)

A novel method for detecting Luttinger-liquid behavior is proposed. The idea is to measure the tunneling conductance between a quantum wire and a parallel two-dimensional electron system as a function of both the potential difference between them, V, and an in-plane magnetic field, B. We show that the two-parameter dependence on B and V allows for a determination of the characteristic dependence on wave vector q and frequency ? of the spectral function, ALL\\(q,?\\), of the quantum wire. In particular, the separation of spin and charge in the Luttinger liquid should manifest itself as singularities in the I- V characteristics. The experimental feasibility of the proposal is discussed.

Altland, Alexander; Barnes, C. H. W.; Hekking, F. W. J.; Schofield, A. J.

1999-08-01

20

Interchain conductivity of coupled Luttinger liquids and organic conductors  

Microsoft Academic Search

We reconsider the theory of dc and ac interchain conductivity in quasi-one dimensional systems. Our results are in good agreement with the measured c-axis optical conductivity of (TMTSF)2ClO4 and suggest that the c-axis dc conductivity of (TMTSF)2PF6 in the 150 KLuttinger liquid at high energy

Antoine Georges; Thierry Giamarchi; Nancy Sandler

2000-01-01

21

From Luttinger to Fermi Liquids in Organic Conductors  

Microsoft Academic Search

This chapter reviews the effects of interactions in quasi-one dimensional systems, such as the Bechgaard and Fabre salts,\\u000a and in particular the Luttinger liquid physics. It discusses in details how transport measurements both d.c. and a.c. allow\\u000a to probe such a physics. It also examine the dimensional crossover and deconfinement transition occurring between the one\\u000a dimensional case and the higher

T. Giamarchi

2007-01-01

22

Plasmon decay and thermal transport from spin-charge coupling in generic luttinger liquids.  

PubMed

We discuss the violation of spin-charge separation in generic nonlinear Luttinger liquids and investigate its effect on the relaxation and thermal transport of genuine spin-1/2 electron liquids in ballistic quantum wires. We identify basic scattering processes compatible with the symmetry of the problem and conservation laws that lead to the decay of plasmons into the spin modes. We derive a closed set of coupled kinetic equations for the spin-charge excitations and solve the problem of thermal conductance of interacting electrons for an arbitrary relation between the quantum wire length and spin-charge thermalization length. PMID:25415912

Levchenko, Alex

2014-11-01

23

Plasmon Decay and Thermal Transport from Spin-Charge Coupling in Generic Luttinger Liquids  

NASA Astrophysics Data System (ADS)

We discuss the violation of spin-charge separation in generic nonlinear Luttinger liquids and investigate its effect on the relaxation and thermal transport of genuine spin-1 /2 electron liquids in ballistic quantum wires. We identify basic scattering processes compatible with the symmetry of the problem and conservation laws that lead to the decay of plasmons into the spin modes. We derive a closed set of coupled kinetic equations for the spin-charge excitations and solve the problem of thermal conductance of interacting electrons for an arbitrary relation between the quantum wire length and spin-charge thermalization length.

Levchenko, Alex

2014-11-01

24

Some Experimental Tests of Tomonaga-Luttinger Liquids  

NASA Astrophysics Data System (ADS)

The Tomonaga-Luttinger-Liquid (TLL) has been the cornerstone of our understanding of the properties of one dimensional systems. This universal set of properties plays in one dimension, the same role than Fermi liquid plays for the higher dimensional metals. I will give in these notes an overview of some of the experimental tests that were made to probe such TLL physics. In particular I will detail some of the recent experiments that were made in spin systems and which provided remarkable quantitative tests of the TLL physics.

Giamarchi, T.

2014-10-01

25

Full counting statistics of a Luttinger liquid conductor.  

PubMed

Nonequilibrium bosonization technique is used to study current fluctuations of interacting electrons in a single-channel quantum wire representing a Luttinger liquid (LL) conductor. An exact expression for the time resolved full counting statistics of the transmitted charge is derived. It is given by the Fredholm determinant of the counting operator with a time-dependent scattering phase. The result has a form of counting statistics of noninteracting particles with fractional charges, induced by scattering off the boundaries between the LL wire and the noninteracting leads. PMID:21231608

Gutman, D B; Gefen, Yuval; Mirlin, A D

2010-12-17

26

Correlations in nonequilibrium Luttinger liquid and singular Fredholm determinants.  

PubMed

We study interaction-induced correlations in Luttinger liquid with multiple Fermi edges. Many-particle correlation functions are expressed in terms of Fredholm determinants det(1+ÂB[over ^]), where A(?) and B(t) have multiple discontinuities in energy and time spaces. We propose a general asymptotic formula for this class of determinants and provide analytical and numerical support to this conjecture. This allows us to establish nonequilibrium Fermi-edge singularities of many-particle correlation functions. As an example, we calculate a two-particle distribution function characterizing genuinely nonequilibrium quantum correlations between left- and right-moving fermions that have left the interaction region. PMID:23745901

Protopopov, I V; Gutman, D B; Mirlin, A D

2013-05-24

27

Multipartite states and Luttinger liquids of composite fermions  

NASA Astrophysics Data System (ADS)

Materials exhibiting exotic quantum phenomena at a macroscopic level are of great interest because of its intrinsic value to Physics, and also because of its potential applications in technology. Strongly correlated electronic systems form interesting examples of these. Exploring them calls for a good understanding of its physics, and development of new tools that are applicable to their analysis. Robustness of the fractional quantum Hall effect (FQHE) makes it an ideal stage to study strongly correlated electron systems. The complexity of the FQHE problem stems directly from the strong interactions between the constituent particles and not from the specific nature of the material it is implemented in. This work attempts to gain a theoretical description of some of the less understood aspects of FQHE. FQHE in the lowest Landau level is well understood using the theory of weakly interacting emergent particles called composite fermions. Composite fermions formed in the second Landau level however appear to be strongly interacting. Of particular interest is the FQHE at 2 + 1/2 filling fraction, where the many body ground state is believed to be described by a paired state of composite fermions, represented by the Pfaffian wavefunction. Based on predicted properties of its excitations, there has been proposals for implementing topological quantum computations in this system. However a good understanding of the nature of these excitations is still lacking. This thesis introduces a class of many body wavefunctions called "bipartite composite fermion states" that provide a unified description of all excitations of the paired state at 5/2. In the bipartite composite fermion (BCF) picture, constituent composite fermions split into two partitions which are correlated to each other. Within each partition, they fill the lowest composite fermion Landau level of its partition. Properties of the BCF state can now be related to the properties of the individual partitions, which are well understood in terms of the composite fermion theory. In particular, we show that the excitations of BCF states are obtained by creating excitations in the individual partitions. The paired state with odd number of composite fermions should have an unpaired composite fermion. The BCF model predicts that this unpaired composite fermion behaves as an exciton in the quasiparticle and quasihole are in separate partitions. We confirm this prediction numerically in finite size systems. Generalizations of bipartite composite fermion functions to other filling fractions especially 2 + 4/7 and 2 + ? are also studied. Idea of bipartite composite fermions can be generalized to the case of more partitions. Specifically, we look at tripartite composite fermion states which are similar to the bipartite states, except that these have three correlated partitions instead of two. Tripartite states have a filling fraction of ? = ?, and its particle hole conjugate is a candidate wavefunction for describing the ? = 2 + ? FQHE. Numerical comparisons of these "multipartite" composite fermion states with exact spectrum of finite systems show that these states give a very good description of the low energy spectra of the corresponding systems. Another interesting aspect of the FQH system is the realization of a chiral Luttinger liquid at the edge of an incompressible state. Effective field theory description of the system makes a non-trivial prediction that tunnelling exponents, which can be experimentally measured, are quantized. Starting from the composite fermion theory, we develop a microscopic model for the edge of the ? = ? filling fraction. The ? edge has composite fermions occupying lowest two composite fermion Landau levels each of which contributes to the edge excitations. The existence of two modes causes the edge spectrum to split into quasi-degenerate sectors of states with each sector representing a specific distribution of the composite fermions in the two levels. Calculations show that in the low energy limit, an electron tunnellin

Ganesh Jaya, Sreejith

28

Impurities in magnetic-field-induced Luttinger liquid  

NASA Astrophysics Data System (ADS)

It has been shown recently(C. Biagini, D. L. Maslov, M. Yu. Reizer and L. I. Glazman, `` Magnetic-field-induced Luttinger liquid''), cond-mat/0006407. that a strong magnetic field applied to a bulk metal may induce a Luttinger liquid phase. This is a consequence of the reduced effective dimensionality of charge carriers from 3D to 1D, an effect which is most pronounced in the ultra-quantum limit, when only the lowest Landau level remains populated. We study the effect of impurities in this system. For the case of a point impurity, the calculation of the scattering cross section at a single impurity can be mapped exactly to a 1D problem of tunneling conductance through a barrier for interacting electrons, solved by Yue et al.(D. Yue, L. I. Glazman and K. A. Matveev, Phys. Rev. B 49) (1994) 1966.. Using this mapping, we find that the longitudinal (?=+1) and transverse (?=-1) Drude conductivities exhibit the scaling laws ?_?? T^??, where ?=2e^2|ln?l_B|/? v_F, and vF and ? are the B-dependent Fermi velocity and screening wavevector, respectively; lB is the magnetic length. The physical reason for such a behavior of the conductivity is the almost 1D form of the Friedel oscillation around a single point impurity in the strong magnetic field.

Tsai, Shan-Wen; Maslov, Dmitrii L.; Glazman, Leonid I.

2001-03-01

29

Quantum Hall Edge Physics and its One-Dimensional Luttinger Liquid Description  

NASA Astrophysics Data System (ADS)

We describe the relationship between quantum Hall edge states and the one-dimensional Luttinger liquid model. The Luttinger liquid model originated from studies of one-dimensional Fermi systems, however, it results that many ideas inspired by such a model can find applications to phenomena occurring even in higher dimensions. Quantum Hall systems which essentially are correlated two-dimensional electronic systems in a strong perpendicular magnetic field have an edge. It turns out that the quantum Hall edge states can be described by a one-dimensional Luttinger model. In this work, we give a general background of the quantum Hall and Luttinger liquid physics and then point out the relationship between the quantum Hall edge states and its one-dimensional Luttinger liquid representation. Such a description is very useful given that the Luttinger liquid model has the property that it can be bosonized and solved. The fact that we can introduce a simpler model of noninteracting bosons, even if the quantum Hall edge states of electrons are interacting, allows one to calculate exactly various quantities of interest. One such quantity is the correlation function which, in the asymptotic limit, is predicted to have a power law form. The Luttinger liquid model also suggests that such a power law exponent should have a universal value. A large number of experiments have found the quantum Hall edge states to show behavior consistent with a Luttinger liquid description. However, while a power law dependence of the correlation function has been observed, the experimental values of the exponent appear not to be universal. This discrepancy might be due to various correlation effects between electrons that sometimes are not easy to incorporate within a standard Luttinger liquid model.

Ciftja, Orion

2014-10-01

30

Luttinger Liquid, Singular Interaction and Quantum Criticality in Cuprate Materials  

NASA Astrophysics Data System (ADS)

With particular reference to the role of the renormalization group (RG) approach and Ward identities (WI's), we start by recalling some old features of the one-dimensional Luttinger liquid as the prototype of non-Fermi-liquid behavior. Its dimensional crossover to the Landau normal Fermi liquid implies that a non-Fermi liquid, as, e.g., the normal phase of the cuprate high temperature superconductors, can be maintained in d > 1 only in the presence of a sufficiently singular effective interaction among the charge carriers. This is the case when, nearby an instability, the interaction is mediated by critical fluctuations. We are then led to introduce the specific case of superconductivity in cuprates as an example of avoided quantum criticality. We will disentangle the fluctuations which act as mediators of singular electron-electron interaction, enlightening the possible order competing with superconductivity and a mechanism for the non-Fermi-liquid behavior of the metallic phase. This paper is not meant to be a comprehensive review. Many important contributions will not be considered. We will also avoid using extensive technicalities and making full calculations for which we refer to the original papers and to the many good available reviews. We will here only follow one line of reasoning which guided our research activity in this field.

di Castro, C.; Caprara, S.

2014-10-01

31

Exact distribution function of a one-dimensional Fro¨hlich-Toyozawa-Luttinger liquid  

NASA Astrophysics Data System (ADS)

An exact analytical expression for the electron momentum distribution function of a one-dimensional Frohlich-Toyozawa-Luttinger (FTL) liquid is obtained. It is explicitly shown that the residual Fermi surface disappears when the electron-electron interaction is increased. It is furthermore shown that the electron-phonon interactions also flatten the distribution function, the optical phonons having a larger effect than the acoustic phonons. However, it is found that the nature of the distribution function of an FTL liquid is qualitatively different from that of the corresponding Luttinger liquid above kF.

Monisha, P. J.; Mukhopadhyay, Soma; Chatterjee, Ashok

2013-07-01

32

Non-Luttinger quantum liquid of one-dimensional spin-orbit-coupled bosons  

NASA Astrophysics Data System (ADS)

We show that the synthetic spin-orbit coupling created in current ultracold atom experiments provides physicists a unique tool to control the Luttinger liquid parameter K of weakly interacting bosons in one dimension. At a critical value of the Raman coupling strength ?c, K is suppressed down to zero, and the characteristic quasi-long-range order for ordinary one-dimensional quantum systems disappears. Consequently, the single-particle correlation function decays exponentially at the ground state, signifying the rise of a one-dimensional quantum many-body state beyond the standard Luttinger liquid paradigm. Momentum distribution, as well as scaling relations for various quantities in the vicinity of the critical point, can be used as a direct diagnosis of this non-Luttinger quantum liquid.

Po, Hoi Chun; Chen, Weiqiang; Zhou, Qi

2014-07-01

33

Direct observation of Tomonaga-Luttinger-liquid state in carbon nanotubes at low temperatures  

Microsoft Academic Search

The electronic transport properties of conventional three-dimensional metals are successfully described by Fermi-liquid theory. But when the dimensionality of such a system is reduced to one, the Fermi-liquid state becomes unstable to Coulomb interactions, and the conduction electrons should instead behave according to Tomonaga-Luttinger-liquid (TLL) theory. Such a state reveals itself through interaction-dependent anomalous exponents in the correlation functions, density

Hiroyoshi Ishii; Hiromichi Kataura; Hidetsugu Shiozawa; Hideo Yoshioka; Hideo Otsubo; Yasuhiro Takayama; Tsuneaki Miyahara; Shinzo Suzuki; Yohji Achiba; Masashi Nakatake; Takamasa Narimura; Mitsuharu Higashiguchi; Hirofumi Namatame; Masaki Taniguchi

2003-01-01

34

Tunneling into 1D and quasi-1D conductors and Luttinger-liquid behavior  

E-print Network

The paper addresses the problem whether and how it is possible to detect the Luttinger-liquid behavior from the IV curves for tunneling to 1D or quasi-1D conductors. The power-law non-ohmic IV curve, which is usually considered as a manifestation of the Luttinger-liquid behavior, can be also deduced from the theory of the Coulomb blockaded junction between 3D conductors affected by the environment effect. In both approaches the power-law exponents are determined by the ratio of the impedance of an effective electric circuit to the quantum resistance. Though two approaches predict different power-law exponents (because of a different choice of effective circuits), the difference becomes negligible for a large number of conductance channels. PACS numbers: 71.10.Pm, 73.23.Hk, 73.63.Fg. 1.

E. B. Sonin

2001-01-01

35

Crossover from the Luttinger-Liquid to Coulomb-Blockade Regime in Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

We develop a theoretical approach to the low-energy properties of one-dimensional electron systems aimed to encompass the mixed features of Luttinger-liquid and Coulomb-blockade behavior observed in the crossover between the two regimes. For this aim, we extend the Luttinger-liquid description by incorporating the effects of a discrete single-particle spectrum. The intermediate regime is characterized by a power-law behavior of the conductance, but with an exponent oscillating with the gate voltage, in agreement with recent experimental observations. Our construction also accounts naturally for the existence of a crossover in the zero-bias conductance, mediating between two temperature ranges where the power-law behavior is preserved but with a different exponent.

Bellucci, S.; González, J.; Onorato, P.

2005-10-01

36

Deconfinement transition and Luttinger to Fermi liquid crossover in quasi-one-dimensional systems.  

PubMed

We investigate a system of one-dimensional Hubbard chains of interacting fermions coupled by interchain hopping. Using a generalization of the dynamical mean-field theory we study the deconfinement transition from a Mott insulator to a metal and the crossover between Luttinger and Fermi liquid phases. One-particle properties, local spin response, and interchain optical conductivity are calculated. Possible applications to organic conductors are discussed. PMID:11800903

Biermann, S; Georges, A; Lichtenstein, A; Giamarchi, T

2001-12-31

37

Many-particle correlations in a non-equilibrium Luttinger liquid  

Microsoft Academic Search

We develop an operator-based approach to the problem of a Luttinger liquid conductor in a non-equilibrium stationary state. We show that the coherent-state many-body fermionic density matrix and all fermionic correlation functions out of equilibrium are given by one-dimensional functional determinants of the Fredholm type. Thus, the model constitutes a remarkable example of a many-body problem where all the correlation

I. V. Protopopov; D. B. Gutman; A. D. Mirlin

2011-01-01

38

Transport Through Luttinger Liquids: The Role of Fermi-Liquid Reservoirs  

NASA Astrophysics Data System (ADS)

The conductance G of one-dimensional Luttinger liquids (LLs) has commonly been believed to exhibit two features: (i) in a perfect LL, the electron-electron interactions renormalize G to the value of Ke^2/h, where K depends on the sign and the strength of interactions; (ii) in the presence of weak disorder, G exhibits characteristic temperature- or length-scalings. However, a recent experiment on ultra-clean GaAs quantum wires(S. Tarucha, T. Honda, and T. Saku, Solid State Comm. 94), 413 (1995). has revealed only the LL-like temperature dependence of G, but no renormalization of G in the ballistic limit (i.e., K=1). In this work, we explore the consequences of the fact that in a typical experiment a LL quantum wire is attached to the wide Fermi-liquid (FL) leads. In particular, it is shown that the dc conductance of a LL wire with FL leads is given by e^2/h, regardless of the interactions in the wire.(D. L. Maslov and M. Stone, Phys. Rev. B52), R5539 (1995). On the other hand, the temperature- and length-dependent corrections are determined by the interactions in the wire.(D. L. Maslov, Phys. Rev. B52), R14368 (1995). These results suggest that the experimental observations by Tarucha et al. can indeed be considered as an indication of the Luttinger-liquid state in GaAs quantum wires. The recently observed crossover from the LL- to the FL-behavior as the number of propagating channels is increased(S. Tarucha, T. Honda, T. Saku, and Y. Tokura (unpublished).) is also discussed. Parts of this work were performed in collaboration with Michael Stone and Nancy Sandler. This work was supported by the National Science Foundation through grants DMR94-24511 and DMR89-20538.

Maslov, Dmitrii L.

1996-03-01

39

Quantum impurity in a Tomonaga-Luttinger liquid: Continuous-time quantum Monte Carlo approach  

NASA Astrophysics Data System (ADS)

We develop a continuous-time quantum Monte Carlo (CTQMC) method for quantum impurities coupled to interacting quantum wires described by a Tomonaga-Luttinger liquid. The method is negative-sign free for any values of the Tomonaga-Luttinger parameter, which is rigorously proved, and, thus, efficient low-temperature calculations are possible. Duality between electrons and bosons in one-dimensional systems allows us to construct a simple formula for the CTQMC algorithm in these systems. We show that the CTQMC for Tomonaga-Luttinger liquids can be implemented with only minor modifications of previous CTQMC codes developed for impurities coupled to noninteracting fermions. We apply this method to the Kane-Fisher model of a potential scatterer in a spin-less quantum wire and to a single spin coupled with the edge state of a two-dimensional topological insulator assuming an anisotropic XXZ coupling. Various dynamical response functions such as the electron Green's function and spin-spin correlation functions are calculated numerically and their scaling properties are discussed.

Hattori, K.; Rosch, A.

2014-09-01

40

Properties of a Luttinger liquid with boundaries at finite temperature and size Ann E. Mattsson,* Sebastian Eggert, and Henrik Johannesson  

E-print Network

as the normal state of 3D interacting electrons is patterned on the free Fermi gas (Landau-Fermi-liquid theory 1D quantum wires,5,6 as well as the development of high-precision spectroscopic techniques of the fractional quantum Hall effect can be described in terms of a chiral Luttinger liquid.8 Also, some

Eggert, Sebastian

41

Kohn-Luttinger effect and the instability of a repulsive Fermi-liquid at T = 0  

SciTech Connect

The author considers the possibility for a pairing instability in a 2D repulsive Fermi-liquid due to the singularity in the scattering amplitude {Gamma}(q) at the momentum transfer q {approx} 2p{sub F} (Kohn-Luttinger effect). For arbitrary Fermi-liquid, {Gamma}(q) for the particles at the Fermi surface is found to have a singular part. For large 2D orbital momentum l, this term gives a dominant attractive contribution to the scattering amplitude and leads to a pairing instability in a 2D Fermi-liquid with arbitrary short-range repulsion. In the dilute limit, numerical studies show that the effect survives down to l = 1 and gives rise to a p-wave pairing. 12 refs.

Chubukov, A.V. [Univ. of Illinois, Urbana (United States)]|[P.L. Kapitza Inst. for Physical Problems, Moscow (Russian Federation)

1992-11-01

42

Time-resolved transport properties of a Y junction of Tomonaga-Luttinger liquid wires  

NASA Astrophysics Data System (ADS)

We study time-resolved transport properties of a Y junction composed of interacting one-dimensional quantum wires using a bosonization approach. In particular, we investigate the ac conductivity of the Y junction formed from finite-length Tomonaga-Luttinger liquid wires based on a plasmon scattering approach for injected charge pulses of arbitrary shapes. In addition, we calculate the tunneling current and quantum noise of the Y junction arising from pointlike tunneling impurities at the junction, including finite-temperature effects. Our results will be useful for designing nanoelectronic quantum circuits and for interpreting time-resolved experiments [Kamata et al., Nat. Nanotechnol. 9, 177 (2014), 10.1038/nnano.2013.312] in interacting wires and their junctions.

Agarwal, Amit

2014-11-01

43

Correlations in non-equilibrium Luttinger liquid and singular Fredholm determinants  

E-print Network

We study interaction-induced correlations in Luttinger liquid with multiple Fermi edges. Many-particle correlation functions are expressed in terms of Fredholm determinants ${\\rm det}(1+\\hat{A}\\hat{B})$, where $A(\\epsilon)$ and $B(t)$ have multiple discontinuities in energy and time spaces. Such determinants are a generalization of Toeplitz determinants with Fisher-Hartwig singularities. We propose a general asymptotic formula for this class of determinants and provide analytical and numerical support to this conjecture. This allows us to establish non-equilibrium power-law singularities of many-particle correlation functions. As an example, we calculate a two-particle distribution function characterizing correlations between left- and right-moving fermions that have left the interaction region.

I. V. Protopopov; D. B. Gutman; A. D. Mirlin

2012-12-04

44

Loschmidt Echo and the Many-Body Orthogonality Catastrophe in a Qubit-Coupled Luttinger Liquid  

NASA Astrophysics Data System (ADS)

We investigate the many-body generalization of the orthogonality catastrophe by studying the generalized Loschmidt echo of Luttinger liquids (LLs) after a global change of interaction. It decays exponentially with system size and exhibits universal behavior: the steady state exponent after quenching back and forth n times between 2 LLs (bang-bang protocol) is 2n times bigger than that of the adiabatic overlap and depends only on the initial and final LL parameters. These are corroborated numerically by matrix-product state based methods of the XXZ Heisenberg model. An experimental setup consisting of a hybrid system containing cold atoms and a flux qubit coupled to a Feshbach resonance is proposed to measure the Loschmidt echo using rf spectroscopy or Ramsey interferometry.

Dóra, Balázs; Pollmann, Frank; Fortágh, József; Zaránd, Gergely

2013-07-01

45

Luttinger-liquid-like behavior in bulk crystals of the quasi-one-dimensional conductor NbSe$_3$  

E-print Network

CDW/Normal metal/CDW junctions and nanoconstrictions in crystals of the quasi-one-dimensional conductor NbSe$_3$ are manufactured using a focused-ion-beam. It is found that the low-temperature conduction of these structures changes dramatically and loses the features of the charge-density-wave transition. Instead, a dielectric phase is developed. Up to 6-order power-law variations of the conduction as a function of both temperature and electric field can be observed for this new phase. The transition from quasi-one-dimensional behavior to one-dimensional behavior is associated with destruction of the three-dimensional order of the charge-density waves by fluctuations. It results in a recovery of the Luttinger-liquid properties of metallic chains, like it takes place in sliding Luttinger liquid phase.

S. V. Zaitsev-Zotov; M. S. H. Go; E. Slot; H. S. J. van der Zant

2001-10-30

46

Chiral Y junction of Luttinger liquid wires at weak coupling: Lines of stable fixed points  

NASA Astrophysics Data System (ADS)

We calculate the conductances of a Y-junction setup of Luttinger liquid wires threaded by a magnetic flux, allowing for a different interaction strength g3?g in the third wire. The scattering matrix and the matrix of conductances are parametrized by three variables. For these we derive coupled renormalization group (RG) equations, up to second order in the interaction, within the scattering state formalism. The fixed point structure of these equations is analyzed in detail. For a repulsive interaction (g,g3>0) there is only one stable fixed point, corresponding to the complete separation of the wires. For an attractive interaction (g<0 and/or g3<0) four fixed points are found, whose stability depends on the interaction strength. For special values of the interaction parameters (a) g=0, g3<0 or (b) g3+g2/2=0, g<0 we find whole lines of stable fixed points. We conjecture that lines of fixed points appear generically at interfaces in the interaction coupling constant space separating two regions with different stable fixed points. We also find that in certain regions of the g-g3 plane the RG flow is towards a fixed point without chirality, implying that the effect of the magnetic flux is completely screened.

Aristov, D. N.; Wölfle, P.

2012-07-01

47

Entanglement spectra between coupled Tomonaga-Luttinger liquids: Applications to ladder systems and topological phases  

NASA Astrophysics Data System (ADS)

We study the entanglement spectrum (ES) and entropy between two coupled Tomonaga-Luttinger liquids (TLLs) on parallel periodic chains. This problem gives access to the entanglement properties of various interesting systems, such as spin ladders as well as two-dimensional topological phases. By expanding interchain interactions to quadratic order in bosonic fields, we are able to calculate the ES for both gapped and gapless systems using only methods for free theories. In certain gapless phases of coupled nonchiral TLLs, we interestingly find an ES with a dispersion relation proportional to the square root of the subsystem momentum, which we relate to a long-range interaction in the entanglement Hamiltonian. We numerically demonstrate the emergence of this unusual dispersion in a model of hard-core bosons on a ladder. In gapped phases of coupled nonchiral TLLs, which are relevant to spin ladders and topological insulators, we show that the ES consists of linearly dispersing modes, which resembles the spectrum of a single-chain TLL but is characterized by a modified TLL parameter. Based on a calculation for coupled chiral TLLs, we are also able to provide a very simple proof for the correspondence between the ES and the edge-state spectrum in quantum Hall systems consistent with previous numerical and analytical studies.

Lundgren, Rex; Fuji, Yohei; Furukawa, Shunsuke; Oshikawa, Masaki

2013-12-01

48

Conductance through a potential barrier embedded in a Luttinger liquid: Nonuniversal scaling at strong coupling  

NASA Astrophysics Data System (ADS)

We calculate the linear response conductance of electrons in a Luttinger liquid with arbitrary interaction g2 , and subject to a potential barrier of arbitrary strength, as a function of temperature. We map the Hamiltonian in the basis of scattering states into an effective low energy Hamiltonian in current algebra form. First the renormalization group (RG) equation for weak interaction is derived in the current operator language both using the operator product expansion and the equation of motion method. To access the strong coupling regime, two methods of deducing the RG equation from perturbation theory, based on the scaling hypothesis and on the Callan-Symanzik formulation, are discussed. The important role of scale-independent terms is emphasized. The latter depend on the regularization scheme used (length versus temperature cutoff). Analyzing the perturbation theory in the fermionic representation, the diagrams contributing to the renormalization group ? -function are identified. A universal part of the ? -function is given by a ladder series and summed to all orders in g2 . First nonuniversal corrections beyond the ladder series are discussed and are shown to differ from the exact solutions obtained within conformal field theory which use a different regularization scheme. The RG equation for the temperature-dependent conductance is solved analytically. Our result agrees with known limiting cases.

Aristov, D. N.; Wölfle, P.

2009-07-01

49

Universal duality in a Luttinger liquid coupled to a generic environment  

NASA Astrophysics Data System (ADS)

We study a Luttinger liquid (LL) coupled to a generic environment consisting of bosonic modes with arbitrary density-density and current-current interactions. The LL can be either in the conducting phase and perturbed by a weak scatterer or in the insulating phase and perturbed by a weak link. The environment modes can also be scattered by the imperfection in the system with arbitrary transmission and reflection amplitudes. We present a general method of calculating correlation functions under the presence of the environment and prove the duality of exponents describing the scaling of the weak scatterer and of the weak link. This duality holds true for a broad class of models and is sensitive to neither interaction nor environmental modes details, thus it shows up as the universal property. It ensures that the environment cannot generate new stable fixed points of the renormalization group flow. Thus, the LL always flows toward either conducting or insulating phase. Phases are separated by a sharp boundary which is shifted by the influence of the environment. Our results are relevant, for example, for low-energy transport in (i) an interacting quantum wire or a carbon nanotube where the electrons are coupled to the acoustic phonons scattered by the lattice defect; (ii) a mixture of interacting fermionic and bosonic cold atoms where the bosonic modes are scattered due to an abrupt local change of the interaction; (iii) mesoscopic electric circuits.

Yurkevich, Igor V.; Yevtushenko, Oleg M.

2014-09-01

50

An Expanded Luttinger Model  

NASA Astrophysics Data System (ADS)

This paper generalizes Luttinger's model by introducing curvature (d2?(k)/dk2 ? 0) into the kinetic energy. An exact solution for arbitrary interactions is still possible in principle, but it now requires disentangling the eigenvalue spectrum of an harmonic string of interacting boson fields at each value of q. The additional boson fields, extracted from the excitation spectrum of the Fermi sea, are self-selected according to the nature and strength of the dispersion.

Mattis, Daniel C.

2014-10-01

51

Many-body luminescence from a ring-shaped dot: Luttinger liquid theory  

NASA Astrophysics Data System (ADS)

Luminescence spectrum of a single photoexcited quantum dot represents a system of very narrow spectral lines corresponding to optical transitions within confined exciton multiplexes.^1 We study theoretically the shape of the luminescence spectrum for quantum dots of a ring geometry, which have been recently fabricated.^2,3 For high excitation intensities, photoexcited electrons and holes form Fermi seas in conduction and valence bands, thus allowing to adopt the Lutinger liquid description. The recombination of an electron-hole pair is accompanied by the emission of the Fermi sea excitations (shake-up effect). We have calculated analytically the oscillator strengths of the many-body luminescence lines as a function of the interaction strength. We find that close to the emission threshold, the many-body lines constitute weak satellites of single-particle transitions. However, away from the emission threshold, the shape of the spectrum is comletely dominated by many-body transitions. ^1See, e.g., E. Dekel et. al, Phys. Rev B 61, 11009 (2000); ibid. 62, 11038 (2000). ^2A. Lorke et. al, Phys. Rev. Lett. 84, 2223 (2000). ^3R. J. Warburton et al, Nature 405, 926 (2000).

Shahbazyan, T. V.; Perakis, I. E.; Raikh, M. E.

2001-03-01

52

Absence of Luttinger liquid behavior in Au-Ge wires: A high-resolution scanning tunneling microscopy and spectroscopy study  

NASA Astrophysics Data System (ADS)

Au-induced atomic wires on the Ge(001) surface were recently claimed to be an ideal one-dimensional (1D) metal and their tunneling spectra were analyzed as the manifestation of a Tomonaga-Luttinger liquid (TLL) state. We reinvestigate this system for atomically well-ordered areas of the surface with high-resolution scanning tunneling microscopy and spectroscopy (STS). The local density-of-states maps do not provide any evidence of a metallic 1D electron channel along the wires. Moreover, the atomically resolved tunneling spectra near the Fermi energy are dominated by local density-of-states features, deviating qualitatively from the power-law behavior. On the other hand, the defects strongly affect the tunneling spectra near the Fermi level. These results do not support the possibility of a TLL state for this system. A 1D metallic system with well-defined 1D bands and without defects are required for the STS study of a TLL state.

Park, Jewook; Nakatsuji, Kan; Kim, Tae-Hwan; Song, Sun Kyu; Komori, Fumio; Yeom, Han Woong

2014-10-01

53

VOLUME 76, NUMBER 17 P H Y S I C A L R E V I E W L E T T E R S 22 APRIL 1996 Thermal Transport in a Luttinger Liquid  

E-print Network

- tral role in the historical development of the quantum theory of solids. The Lorentz number, L k s for these are 1D interacting electron gas models, which exhibit a non-Fermi-liquid phase even for weak in the fractional quantum Hall effect are Luttinger liquids [6]. Other non-Fermi-liquid phases arise in quantum

Kane, Charles

54

Elementary Excitations in Quantum Liquids.  

ERIC Educational Resources Information Center

Discusses elementary excitations and their role in condensed matter physics, focusing on quantum plasma, helium liquids, and superconductors. Considers research primarily conducted in the 1950s and concludes with a brief survey of some closely related further developments. (Author/JN)

Pines, David

1981-01-01

55

Field-Induced Tomonaga-Luttinger Liquid Phase of a Two-Leg Spin-1/2 Ladder with Strong Leg Interactions  

NASA Astrophysics Data System (ADS)

We study the magnetic-field-induced quantum phase transition from a gapped quantum phase that has no magnetic long-range order into a gapless phase in the spin-1/2 ladder compound bis(2,3-dimethylpyridinium) tetrabromocuprate (DIMPY). At temperatures below about 1 K, the specific heat in the gapless phase attains an asymptotic linear temperature dependence, characteristic of a Tomonaga-Luttinger liquid. Inelastic neutron scattering and the specific heat measurements in both phases are in good agreement with theoretical calculations, demonstrating that DIMPY is the first model material for an S=1/2 two-leg spin ladder in the strong-leg regime.

Hong, Tao; Kim, Y. H.; Hotta, C.; Takano, Y.; Tremelling, G.; Turnbull, M. M.; Landee, C. P.; Kang, H.-J.; Christensen, N. B.; Lefmann, K.; Schmidt, K. P.; Uhrig, G. S.; Broholm, C.

2010-09-01

56

Field-induced Tomonaga-Luttinger liquid phase of a two-leg spin-1/2 ladder with strong leg interactions  

SciTech Connect

We study the magnetic-field-induced quantum phase transition from a gapped quantum phase that has no magnetic long-range order into a gapless phase in the spin-1/2 ladder compound bis(2,3-dimethylpyridinium) tetrabromocuprate (DIMPY). At temperatures below about 1 K, the specific heat in the gapless phase attains an asymptotic linear temperature dependence, characteristic of a Tomonaga-Luttinger liquid. Inelastic neutron scattering and the specific heat measurements in both phases are in good agreement with theoretical calculations, demonstrating that DIMPY is the first model material for an S=1/2 two-leg spin ladder in the strong-leg regime.

Kim, Y. H. [University of Florida, Gainesville; Hotta, C. [Kyoto Sangyo University; Takano, Y. [University of Florida, Gainesville; Tremelling, G. [Clark University; Turnbull, M. M. [Clark University; Landee, C. [Clark University; Kang, H.-J. [NIST Center for Neutron Research (NCRN), Gaithersburg, MD; Christensen, N. B. [Laboratory for Neutron Scattering ETHZ & PSI; Lefmann, K. [Riso National Laboratory, Roskilde, Denmark; Schmidt, K. P. [Technische Universit Dortmund, Germany; Uhrig, G. S. [Technische Universit Dortmund, Germany; Broholm, C. [Johns Hopkins University

2010-01-01

57

Field-induced Tomonaga-Luttinger liquid phase of a two-leg spin-1/2 ladder with strong leg interactions.  

PubMed

We study the magnetic-field-induced quantum phase transition from a gapped quantum phase that has no magnetic long-range order into a gapless phase in the spin-1/2 ladder compound bis(2,3-dimethylpyridinium) tetrabromocuprate (DIMPY). At temperatures below about 1 K, the specific heat in the gapless phase attains an asymptotic linear temperature dependence, characteristic of a Tomonaga-Luttinger liquid. Inelastic neutron scattering and the specific heat measurements in both phases are in good agreement with theoretical calculations, demonstrating that DIMPY is the first model material for an S=1/2 two-leg spin ladder in the strong-leg regime. PMID:21230808

Hong, Tao; Kim, Y H; Hotta, C; Takano, Y; Tremelling, G; Turnbull, M M; Landee, C P; Kang, H-J; Christensen, N B; Lefmann, K; Schmidt, K P; Uhrig, G S; Broholm, C

2010-09-24

58

Renormalization Group and Asymptotic Spin--Charge separation for Chiral Luttinger liquids  

E-print Network

The phenomenon of Spin-Charge separation in non-Fermi liquids is well understood only in certain solvable d=1 fermionic systems. In this paper we furnish the first example of asymptotic Spin-Charge separation in a d=1 non solvable model. This goal is achieved using Renormalization Group approach combined with Ward-Identities and Schwinger-Dyson equations, corrected by the presence of a bandwidth cut-offs. Such methods, contrary to bosonization, could be in principle applied also to lattice or higher dimensional systems.

P. Falco; V. Mastropietro

2007-07-19

59

Field-induced Tomonaga-Luttinger liquid phase of a two-leg spin-1/2 ladder with strong leg interactions  

NASA Astrophysics Data System (ADS)

We study the magnetic-field-induced quantum phase transition from a gapped quantum phase that has no magnetic long-range order into a gapless phase in the spin-1/2 ladder compound bis(2,3-dimethylpyridinium) tetrabromocuprate (DIMPY) [1]. At temperatures below about 1 K, the specific heat in the gapless phase attains an asymptotic linear temperature dependence, characteristic of a Tomonaga-Luttinger liquid. Inelastic neutron scattering and the specific heat measurements in both phases are in good agreement with theoretical calculations, demonstrating that DIMPY is the first model material for an S=1/2 two-leg spin ladder in the strong-leg regime. [4pt] [1] T. Hong et al., Phys. Rev. Lett. 105, 137207 (2010)

Hong, Tao; Kim, Y. H.; Hotta, C.; Takano, Y.; Tremelling, G.; Turnbull, M. M.; Landee, C. P.; Kang, H.-J.; Christensen, N. B.; Lefmann, K.; Schmidt, K. P.; Uhrig, G. S.; Broholm, C.

2011-03-01

60

Conduction anisotropy and Hall effect in the organic conductor (TMTTF )2 AsF6 : Evidence for Luttinger liquid behavior and charge ordering  

NASA Astrophysics Data System (ADS)

We present the high-temperature (70KLuttinger liquid features appear in the transport properties. Our measurements also give strong evidence of charge ordering in (TMTTF)2AsF6 . At the charge-ordering transition TCO?100K , RH(T) abruptly changes its behavior, switches sign, and rapidly increases with further temperature decrease.

Korin-Hamzi?, Bojana; Tafra, Emil; Basleti?, Mario; Hamzi?, Amir; Dressel, Martin

2006-03-01

61

Correlation functions for the detection of Wigner molecules in a one-channel Luttinger liquid quantum dot  

NASA Astrophysics Data System (ADS)

In one-channel, finite-size Luttinger one-dimensional quantum dots, both Friedel oscillations and Wigner correlations induce oscillations in the electron density with the same wavelength, pinned at the same position. Therefore, observing such a property does not provide any hint about the formation of a Wigner molecule when electrons interact strongly and other tools must be employed to assess the formation of such correlated states. We compare here the behavior of three different correlation functions and demonstrate that the integrated two point correlation function, which represents the probability density of finding two particles at a given distance, is the only faithful estimator for the formation of a correlated Wigner molecule.

Gambetta, F. M.; Traverso Ziani, N.; Cavaliere, F.; Sassetti, M.

2014-08-01

62

Equilibration of a one-dimensional quantum liquid  

SciTech Connect

We review some of the recent results on equilibration of one-dimensional quantum liquids. The low-energy properties of these systems are described by the Luttinger liquid theory, in which the excitations are bosonic quasiparticles. At low temperatures, the relaxation of the gas of excitations toward full equilibrium is exponentially slow. In electronic Luttinger liquids, these relaxation processes involve backscattering of electrons and give rise to interesting corrections to the transport properties of one-dimensional conductors. We focus on the phenomenological theory of the equilibration of a quantum liquid and obtain an expression for the relaxation rate in terms of the excitation spectrum.

Matveev, K. A., E-mail: matveev@anl.gov [Argonne National Laboratory Argonne, Materials Science Division (United States)

2013-09-15

63

Metal-semiconductor transition and Luttinger-liquid behavior in quasi-one-dimensional BaVS3 studied by photoemission spectroscopy  

NASA Astrophysics Data System (ADS)

The quasi-one-dimensional conductor BaVS3 exhibits successive phase transitions at ~240 K (linear chains to zigzag chains), ~70 K (metallic to semiconducting), and ~35 K (paramagnetic to antiferromagnetic). We have made high-resolution ultraviolet-photoemission-spectroscopy (UPS), x-ray-photoemission-spectroscopy, electrical-resistivity, and magnetic-susceptibility measurements on BaVS3. UPS spectra near the Fermi level of the metallic phase exhibit a power-law dependence on the electron binding energy, indicating that conduction electrons in BaVS3 behave as a Luttinger liquid. The power-law exponent is large (<~1), indicating that electron-electron interaction is long ranged and possibly that electron-phonon interaction is also important. The spectra exhibit gradual changes with temperature. In particular, a semiconducting gap starts to open well above the metal-to-semiconductor transition temperature and fully develops below it. We propose that the gradual orthorhombic distortion of the Jahn-Teller type below ~240 K lowers one of the d levels, dxy, and that below ~70 K electrons are fully transferred to the dxy band. The dxy band then becomes half-filled, resulting in the opening of a Mott-Hubbard gap.

Nakamura, M.; Sekiyama, A.; Namatame, H.; Fujimori, A.; Yoshihara, H.; Ohtani, T.; Misu, A.; Takano, M.

1994-06-01

64

Liquid storage tanks under vertical excitation  

SciTech Connect

Until recently, the hydrodynamic effects on liquid storage tanks induced by an earthquake excitation were basically treated for the horizontal component of the earthquake. Recent studies, however, showed that the hydrodynamic effects due to the vertical component of an earthquake may be significant. In these studies the tank is assumed to be fixed at the bottom. This paper is concerned with the hydrodynamic behavior of liquid storage tanks induced by vertical earthquake input excitation. First, the fluid-tank system is treated as a fixed-base system and a simple formula is obtained for the coupled fluid-structure natural frequency. Second, additional interaction effects due to the foundation flexibility on the fluid-tank system are investigated. It is concluded that the foundation flexibility may have a significant effect on the hydrodynamic behavior of the liquid storage tanks under a vertical ground shaking.

Philippacopoulos, A.J.

1985-01-01

65

Kohn-Luttinger effect and the instability of a two-dimensional repulsive Fermi liquid at [ital T]=0  

SciTech Connect

We consider the possibility for a pairing in a two-dimensional (2D) repulsive Fermi liquid due to the singularity in the scattering amplitude [Gamma]([ital q]) at the momentum transfer [ital q][le]2[ital p][sub [ital F

Chubukov, A.V. (Department of Physics and Center for Superconductivity, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801 (United States) P. L. Kapitza Institute for Physical Problems, 117973, ul. Kosygina 2, Moscow (Russian Federation))

1993-07-01

66

Luttinger surgery and Kodaira dimension  

E-print Network

In this note we show that the Lagrangian Luttinger surgery preserves the symplectic Kodaira dimension. Some constraints on Lagrangian tori in symplectic four manifolds with non-positive Kodaira dimension are also derived.

Ho, Chung-I

2011-01-01

67

Collective excitations in an ionic liquid.  

PubMed

Collective dynamics in a representative model of ionic liquids, namely, 1-butyl-3-methylimidazolium chloride, have been revealed by molecular dynamics simulation. Dispersion of energy excitation, omega versus k, of longitudinal acoustic (LA) and transverse acoustic (TA) modes was obtained in the wave vector range 0.17 < k < 1.40 Angstroms(-1), which encompasses the main peak of the static structure factor S(k). Linear dispersion of acoustic modes is observed up to k approximately 0.7 Angstroms(-1). Due to mixing between LA and TA modes, LA spectra display transverselike component, and vice versa. Due to anisotropy in short-time ionic dynamics, acoustic modes achieve distinct limiting omega values at high k when the cation displacement is projected either along the plane or perpendicular to the plane of the imidazolium ring. In charge current spectra, branch with negative dispersion of omega versus k is a signature of optic modes in the simulated ionic liquid. Conductivity kappa estimated by using ionic diffusion coefficients in the Nernst-Einstein equation is higher than the actual kappa calculated by integrating the charge current correlation function. From TA spectra, a wave vector dependent viscosity eta(k) has been evaluated, whose low-k limit gives eta in reasonable agreement with experimental data. PMID:16497063

Urahata, Sérgio M; Ribeiro, Mauro C C

2006-02-21

68

Collective excitations in an ionic liquid  

NASA Astrophysics Data System (ADS)

Collective dynamics in a representative model of ionic liquids, namely, 1-butyl-3-methylimidazolium chloride, have been revealed by molecular dynamics simulation. Dispersion of energy excitation, ? versus k, of longitudinal acoustic (LA) and transverse acoustic (TA) modes was obtained in the wave vector range 0.17liquid. Conductivity ? estimated by using ionic diffusion coefficients in the Nernst-Einstein equation is higher than the actual ? calculated by integrating the charge current correlation function. From TA spectra, a wave vector dependent viscosity ?(k ) has been evaluated, whose low-k limit gives ? in reasonable agreement with experimental data.

Urahata, Sérgio M.; Ribeiro, Mauro C. C.

2006-02-01

69

Elementary excitations of liquid 4 He in aerogel  

E-print Network

Elementary excitations of liquid 4 He in aerogel O. Plantevin and B. Fa°k Commissariat a` l-roton excitations of liquid 4 He immersed in aerogel of 95% porosity have been measured using inelastic neutron.25 K. Aerogel grown with deuterated materials not exposed to air was used and measure- ments in bulk

Glyde, Henry R.

70

Tomonaga-Luttinger physics in electronic quantum circuits.  

PubMed

In one-dimensional conductors, interactions result in correlated electronic systems. At low energy, a hallmark signature of the so-called Tomonaga-Luttinger liquids is the universal conductance curve predicted in presence of an impurity. A seemingly different topic is the quantum laws of electricity, when distinct quantum conductors are assembled in a circuit. In particular, the conductances are suppressed at low energy, a phenomenon called dynamical Coulomb blockade. Here we investigate the conductance of mesoscopic circuits constituted by a short single-channel quantum conductor in series with a resistance, and demonstrate a proposed link to Tomonaga-Luttinger physics. We reformulate and establish experimentally a recently derived phenomenological expression for the conductance using a wide range of circuits, including carbon nanotube data obtained elsewhere. By confronting both conductance data and phenomenological expression with the universal Tomonaga-Luttinger conductance curve, we demonstrate experimentally the predicted mapping between dynamical Coulomb blockade and the transport across a Tomonaga-Luttinger liquid with an impurity. PMID:23653214

Jezouin, S; Albert, M; Parmentier, F D; Anthore, A; Gennser, U; Cavanna, A; Safi, I; Pierre, F

2013-01-01

71

Luttinger-like parameter calculations  

SciTech Connect

We have calculated the Luttinger-like parameters, used in the 8{times}8 Hamiltonian describing both conduction and valence bands, via a second-order perturbation theory that allows one to make the Lowdin renormalization valid for a set of nondegenerate energy levels. We show that the formulas given in the paper by Pidgeon and Brown [Phys. Rev. >146, 575 (1966)] are the correct ones, contrary to what is claimed in recent papers. This leads to strong discrepancies when the spin-orbit splitting is not much smaller than the band gap. For example, the ratio between the Luttinger-like parameters {tilde {gamma}}{sub 1}, calculated in the two cases, is of the order of 1.5 in GaAs, 3 in InAs, and 16 in InSb. The accuracy of the equations used by Pidgeon and Brown is also discussed.

Boujdaria, Kais; Ridene, Said; Fishman, Guy

2001-06-15

72

Thermal Excitations in Liquid He3  

Microsoft Academic Search

Using recently obtained data on various thermal properties of liquid He3, the constant-volume heat capacity of the saturated liquid has been evaluated. This elementary heat capacity Cv(T) was found to exhibit at least three inflection points over the temperature interval extending to the critical temperature. Of these, the one at the lowest temperature was shown to originate with the partial

Louis Goldstein

1958-01-01

73

The liquid to vapor phase transition in excited nuclei  

SciTech Connect

For many years it has been speculated that excited nuclei would undergo a liquid to vapor phase transition. For even longer, it has been known that clusterization in a vapor carries direct information on the liquid-vapor equilibrium according to Fisher's droplet model. Now the thermal component of the 8 GeV/c pion + 197 Au multifragmentation data of the ISiS Collaboration is shown to follow the scaling predicted by Fisher's model, thus providing the strongest evidence yet of the liquid to vapor phase transition.

Elliott, J.B.; Moretto, L.G.; Phair, L.; Wozniak, G.J.; Beaulieu, L.; Breuer, H.; Korteling, R.G.; Kwiatkowski, K.; Lefort, T.; Pienkowski, L.; Ruangma, A.; Viola, V.E.; Yennello, S.J.

2001-05-08

74

16. Zaanen, J., Osman, Y., Kruis, H. V., Nussinov, Z. & Tworzydlo, J. The geometric order of stripes and Luttinger liquids. Phil. Mag. B 81, 14851531 (2001).  

E-print Network

Ministry of Education, Culture, Sports, Science and Technology. Work was supported in part by the US. Ito, M. et al. Effects of "stripes" on the magnetic excitation spectra of La1.48Nd0.4Sr0.12CuO4. J that they have no competing financial interests. Correspondence and requests for materials should be addressed

75

Sum rules and spin multipair excitations in liquid 3He  

NASA Astrophysics Data System (ADS)

Multipair excitations in liquid 3He at low temperature are investigated using a sum-rule approach. The m3=FS(q,?)?3 d? sum rule is calculated microscopically by properly accounting for short-range correlations. The average spin multipair (mp) energy ?i31[mi3(mp)/mi1(mp)]1/2 is found to be ~50 K in the low-q limit. A rigorous lower bound for the multipair contribution to the static form factor in the low-q limit is derived. The relative importance of coherent and spin-dependent multipair excitations is also discussed.

Dalfovo, F.; Stringari, S.

1989-07-01

76

Excited state dynamics of liquid water: Insight from the dissociation reaction following two-photon excitation  

E-print Network

We use transient absorption spectroscopy to monitor the ionization and dissociation products following two-photon excitation of pure liquid water. The two decay mechanisms occur with similar yield for an excitation energy of 9.3 eV, whereas the major channel at 8.3 eV is dissociation. The geminate recombination kinetics of the H and OH fragments, which can be followed in the transient absorption probed at 267 nm, provide a window on the dissociation dynamics at the lower excitation energy. Modeling the OH geminate recombination indicates that the dissociating H atoms have enough kinetic energy to escape the solvent cage and one or two additional solvent shells. The average initial separation of H and OH fragments is 0.7+-0.2 nm. Our observation suggests that the hydrogen bonding environment does not prevent direct dissociation of an O-H bond in the excited state. We discuss the implications of our measurement for the excited state dynamics of liquid water and explore the role of those dynamics in the ionizati...

Elles, C G; Crowell, R A; Shkrob, I A; Bradforth, Stephen E.; Crowell, Robert A.; Elles, Christopher G.; Shkrob, Ilya A.

2007-01-01

77

Edge physics of the quantum spin Hall insulator from a quantum dot excited by optical absorption.  

PubMed

The gapless edge modes of the quantum spin Hall insulator form a helical liquid in which the direction of motion along the edge is determined by the spin orientation of the electrons. In order to probe the Luttinger liquid physics of these edge states and their interaction with a magnetic (Kondo) impurity, we consider a setup where the helical liquid is tunnel coupled to a semiconductor quantum dot that is excited by optical absorption, thereby inducing an effective quantum quench of the tunneling. At low energy, the absorption spectrum is dominated by a power-law singularity. The corresponding exponent is directly related to the interaction strength (Luttinger parameter) and can be computed exactly using boundary conformal field theory thanks to the unique nature of the quantum spin Hall edge. PMID:24766003

Vasseur, Romain; Moore, Joel E

2014-04-11

78

One-dimensional Hubbard-Luttinger model for carbon nanotubes  

E-print Network

A Hubbard-Luttinger model is developed for qualitative description of one-dimensional motion of interacting Pi-conductivity-electrons in carbon single-wall nanotubes at low temperatures. The low-lying excitations in one-dimensional electron gas are described in terms of interacting bosons. The Bogolyubov transformation allows one to describe the system as an ensemble of non-interacting quasi-bosons. Operators of Fermi-excitations and Green functions of fermions are introduced. The electric current is derived as a function of potential difference on the contact between a nanotube and a normal metal. Deviations from Ohm law produced by electron-electron short-range repulsion as well as by the transverse quantization in single-wall nanotubes are discussed. The results are compared with experimental data.

Ishkhanyan, H A

2014-01-01

79

Sum rules and spin multipair excitations in liquid 3He  

Microsoft Academic Search

Multipair excitations in liquid 3He at low temperature are investigated using a sum-rule approach. The m3=FS(q,omega)omega3 domega sum rule is calculated microscopically by properly accounting for short-range correlations. The average spin multipair (mp) energy omegai31[mi3(mp)\\/mi1(mp)]1\\/2 is found to be ~50 K in the low-q limit. A rigorous lower bound for the multipair contribution to the static form factor in the

F. Dalfovo; S. Stringari

1989-01-01

80

Collective Excitations of Holographic Quantum Liquids in a Magnetic Field  

E-print Network

We use holography to study N=4 supersymmetric SU(Nc) Yang-Mills theory in the large-Nc and large-coupling limits coupled to a number Nf > T,\\sqrt{B}. We study the collective excitations of these holographic quantum liquids by computing the poles in the retarded Green's function of the baryon number charge density operator and the associated peaks in the spectral function. We focus on the evolution of the collective excitations as we increase the frequency relative to T, i.e. the hydrodynamic/collisionless crossover. We find that for all B, at low frequencies the tallest peak in the spectral function is associated with hydrodynamic charge diffusion. At high frequencies the tallest peak is associated with a sound mode similar to the zero sound mode in the collisionless regime of a Landau Fermi liquid. The sound mode has a gap proportional to B, and as a result for intermediate frequencies and for B sufficiently large compared to T the spectral function is strongly suppressed. We find that the hydrodynamic/collisionless crossover occurs at a frequency that is approximately B-independent.

Daniel K. Brattan; Richard A. Davison; Simon A. Gentle; Andy O'Bannon

2012-08-31

81

Parametric excitation of collective modes in an electron layer on a liquid surface  

Microsoft Academic Search

Parametric excitations of electrostatic oscillations in a two-dimensional electron gas on a liquid surface and a surface wave (ripplon) of the liquid are studied. The excitations are achieved by an oscillating (pump) electric field along the liquid surface at a frequency near the characteristic frequency of the two-dimensional electron gas. The threshold value of the pump field depends, among other

Kunioki Mima; Hiroyuki Ikezi; Akira Hasegawa

1976-01-01

82

Generalization of Luttinger’s theorem for strongly correlated electron systems  

Microsoft Academic Search

By on the analyzing the general structure of the Green function of a strongly correlated electron system, it is shown that,\\u000a for the regime of strong correlations, Luttinger’s theorem should be generalized in the following way: the volume of the Fermi\\u000a surface of the system of noninteracting particles is equal to that of the quasiparticles in the strongly correlated system

M. M. Korshunov; S. G. Ovchinnikov

2003-01-01

83

Polarized neutron scattering investigation of excitations at low momentum transfer in liquid Ga: The mystery continues  

E-print Network

Polarized neutron scattering investigation of excitations at low momentum transfer in liquid Ga: Liquid metals; Scattering; Excitations; Sum-rule violation New polarized neutron scattering experiments in the literature. Our polarized neutron scattering experiments show that this increased cross-section cannot

Montfrooij, Wouter

84

Advanced nanoparticle generation and excitation by lasers in liquids.  

PubMed

Today, nanoparticles are widely implemented as functional elements onto surfaces, into volumes and as nano-hybrids, resulting for example in bioactive composites and biomolecule conjugates. However, only limited varieties of materials compatible for integration into advanced functional materials are available: nanoparticles synthesized using conventional gas phase processes are often agglomerated into micro powders that are hard to re-disperse into functional matrices. Chemical synthesis methods often lead to impurities of the nanoparticle colloids caused by additives and precursor reaction products. In the last decade, laser ablation and nanoparticle generation in liquids has proven to be a unique and efficient technique to generate, excite, fragment, and conjugate a large variety of nanostructures in a scalable and clean manner. This editorial briefly highlights selected recent advancements and critical aspects in the field of pulsed laser-based nanoparticle generation and manipulation, including exemplary strategies to harvest the unique properties of the laser-generated nanomaterials in the field of biomedicine and catalysis. The presented critical aspects address future assignments such as size control and scale-up. PMID:23138867

Barcikowski, Stephan; Compagnini, Giuseppe

2013-03-01

85

A numerical study of liquid sloshing in a two-dimensional tank under external excitations  

NASA Astrophysics Data System (ADS)

In this research, liquid sloshing behavior in a 2-D rectangular tank was simulated using ANSYS-FLUENT software subject to single or multiple-coupled external excitations (such as sway coupled with roll, and sway and roll coupled with heave). The volume of fluid (VOF) method was used to track the free surface of sloshing. External excitation was imposed through the motion of the tank by using the dynamic mesh technique. The study shows that if the tank is subjected to multiple coupled excitations and resonant excitation frequencies, liquid sloshing will become violent and sloshing loads, including impact on the top wall, will be intensified.

Hou, Ling; Li, Fangcheng; Wu, Chunliang

2012-09-01

86

Magnetoelastic excitations in the pyrochlore spin liquid Tb2Ti2O7.  

PubMed

At low temperatures, Tb2Ti2O7 enters a spin liquid state, despite expectations of magnetic order and/or a structural distortion. Using neutron scattering, we have discovered that in this spin liquid state an excited crystal field level is coupled to a transverse acoustic phonon, forming a hybrid excitation. Magnetic and phononlike branches with identical dispersion relations can be identified, and the hybridization vanishes in the paramagnetic state. We suggest that Tb2Ti2O7 is aptly named a "magnetoelastic spin liquid" and that the hybridization of the excitations suppresses both magnetic ordering and the structural distortion. The spin liquid phase of Tb2Ti2O7 can now be regarded as a Coulomb phase with propagating bosonic spin excitations. PMID:24483925

Fennell, T; Kenzelmann, M; Roessli, B; Mutka, H; Ollivier, J; Ruminy, M; Stuhr, U; Zaharko, O; Bovo, L; Cervellino, A; Haas, M K; Cava, R J

2014-01-10

87

Diffusion Monte Carlo for excited states: Application to liquid helium  

Microsoft Academic Search

The extension of ab initio Monte Carlo methods to the study of excited states is a challenging problem at the forefront of\\u000a present research in the field of computational techniques applied to the quantum many-body problem. The aim is to calculate\\u000a excited states with similar accuracy to the one achieved in the study of the ground-state properties. We present a

Jordi Boronat; Departament de Fisica

1998-01-01

88

On the Kohn-Luttinger conundrum  

SciTech Connect

Kohn and Luttinger [Phys. Rev. 118, 41 (1960)] showed that the conventional finite-temperature extension of the second-order many-body perturbation theory had the incorrect zero-temperature limit in metals and, on this basis, argued that the theory was incorrect. We show that this inconsistency arises from the noninclusion of the temperature effect in the energies of the zeroth-order eigenstates of the perturbation theory, which causes not only the Kohn-Luttinger conundrum but also another inconsistency with the zero-temperature many-body perturbation theory, namely, the different rates of divergence of the correlation energy in a homogeneous electron gas (HEG). We propose a renormalized many-body perturbation theory derivable from the finite-temperature extension of the normal-ordered second quantization applied to the denominators of the energy expression, which involves the energies of the zeroth-order states, as well as to the numerators. The renormalized theory is shown to have the correct zero-temperature limit and the same rate of divergence in a HEG as the zero-temperature counterpart, and is, therefore, the correct finite-temperature many-body perturbation theory.

Hirata, So [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801 (United States); CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); He Xiao [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801 (United States)

2013-05-28

89

Analysis of strong acoustic excitation on the breakup and dispersion of a liquid jet  

Microsoft Academic Search

The effect of strong acoustic waves on the breakup and dispersion of cylindrical liquid jets is considered with regard to combustion instabilities of liquid injection burners. An experimental study showed that a strong acoustic excitation modifies jet stability at low injection velocities (by reduction of the breakup length). This phenomenon, which exhibits saturation and threshold effects, is especially sensitive to

Bernard Labegorre

1993-01-01

90

Two-dimensional Yukawa liquids: structure and collective excitations  

NASA Astrophysics Data System (ADS)

The paper reports molecular dynamics (MD) simulations on two-dimensional, strongly-coulped Yukawa liquids. An effective coupling coefficient ?* for the liquid phase is identified; thermodynamic properties such as internal energy, pressure and compressibility, as well as longitudinal and transverse mode dispersions are analysed.

Hartmann, P.; Kalman, G. J.; Donkó, Z.

2006-04-01

91

Response of a rotating finite annular liquid layer to axial excitation  

Microsoft Academic Search

A solidly rotating finite annular liquid layer consisting of nonviscous liquid is subjected to axial harmonic excitation in\\u000a a zerogravity environment. The response of the free liquid surface elevation and the velocity in radial and axial direction\\u000a have been determined in the elliptic forcing frequency range ?>2?0 and in the hyperbolic range ?>2?0 for different diameter ratios.

Helmut F. Bauer

1989-01-01

92

A conjecture concerning collective excitations in liquid water  

NASA Astrophysics Data System (ADS)

We show that the distribution of rings of water molecules in a molecular dynamics simulation of liquid water is consistent with the hypothesis that there are collective coordinates that convert 6-rings to n-rings.

Rice, Stuart A.; Belch, Alan C.; Sceats, Mark G.

1981-12-01

93

Luttinger Model in Dimensions d > 1  

NASA Astrophysics Data System (ADS)

In the present work the Luttinger model is formally extended to d > 1 dimensions. For purposes of comparison with the original model only short-range forces linking the fermions have been considered (as in the Hubbard model). The Fermi sea is decomposed into sectors labeled by wave-vectors q, each containing a set of orthogonal, independent normal modes. Operators that create or destroy normal modes within any given sector are shown to commute with those originating in other sectors. Because the Hamiltonian within each sector is a quadratic form in these normal modes it can be diagonalized in a multitude of ways. One convenient method consists of mapping it onto a model first introduced elsewhere in this volume, the d = 1 expanded Luttinger model. It too can be diagonalized, albeit not so trivially as the original, but by constructing and then diagonalizing a boson string. A product of eigenstates -- one from each sector -- is used to construct an exact eigenstate of the full many-body problem if the algebra connecting all the normal modes is Abelian. However, some form of non-Abelian algebra governs the normal modes in the presence of any sort of long-range order (LRO), whether ferromagnetic, antiferromagnetic or superconducting. (Note that the Mermin-Wagner theorem does preclude spontaneous LRO in dimensions d ? 2). Although it is also important to understand the nature of dynamical exchange corrections to arbitrary-range interactions -- including the physically important Coulomb interaction -- a detailed derivation, together with such other conundrum as the calculation of one-fermion distribution functions from "first principles," all are topics relegated to future publications.

Mattis, Daniel C.

2014-10-01

94

Excitations and Bose-Einstein condensation in liquid 4He  

NASA Astrophysics Data System (ADS)

We present a model of the dynamic structure factor S(Q,?) of He4 that reproduces the basic features of the temperature dependence of S(Q,?) as observed in inelastic-neutron scattering measurements. Wave vectors Q beyond the roton ( Q>2.0Å-1 ) are considered. The model is able to reproduce the decrease in the intensity of the single excitation (phonon-roton) peak in S(Q,?) with an increase of temperature (T) in the range 0.6?T?2.1K . All vertices and interactions are assumed temperature independent, and only the condensate fraction n0(T) changes with T . Also, it reproduces a second peak observed at higher energy ( ? ) which represents the single excitation intensity lying in the two excitation band. The model is based on the formulation of S(Q,?) of Gavoret and Nozières. In this formulation, the dynamic susceptibility, ? , is separated into a singular part involving the condensate and a regular part involving states above the condensate ?=?S+?R' . The weight of the phonon-roton peak in ?S is proportional to n0(T) and the phonon-roton peak disappears completely from ? in the normal phase where n0(T)=0 . Using sum rule arguments, the condensate fraction can be estimated from the data giving values in good agreement with accurate measurements at SVP and with Monte Carlo calculations.

Sakhel, A. R.; Glyde, H. R.

2004-10-01

95

Sloshing response of nonuniform density liquid in a laterally excited tank  

SciTech Connect

A study on the sloshing response of nonuniform density liquid in a tank undergoing lateral base excitations is presented. The system considered is a circular cylindrical tank containing a liquid whose density increases with the liquid depth. The density distribution along the depth can be of any arbitrary continuous function. In the analysis, the liquid field is divided into n layers. The thicknesses of the liquid layers can be different, but the density of each liquid layer is considered to be uniform and its value is assigned to be the value of the original liquid density at the mid-height of that layer. The problem is solved by the transfer matrix technique. The effect of the nonuniform liquid density on the sloshing response is illustrated in a numerical example in which the linear and cosine distributions of the liquid density are assumed. The response functions examined include the sloshing frequencies, surface wave height, and the associated convective hydrodynamic pressure. The results are presented in tabular and graphical forms. It is found that the natural frequencies of the sloshing motion for nonuniform density liquid are lower than those of the uniform density liquid of the same total depth contained in an identical tank. Also, it is shown that for nonuniform density liquid, the maximum sloshing wave height may increase significantly and the magnitude of the convective hydrodynamic pressure may be quite different compared with that of a uniform liquid contained in an identical tank.

Tang, Y. [Argonne National Lab., IL (United States). Reactor Engineering Division

1995-01-01

96

Pressure dependence of elementary excitations in normal liquid helium-3  

Microsoft Academic Search

The neutron scattering function for liquid 3He at 120 mK and pressures of 9, 0.5, 1, and 2 MPa has been determined for wave vectors in the range 3 nm-1

R. Scherm; K. Guckelsberger; B. Fak; K. Sköld; A. J. Dianoux; H. Godfrin; W. G. Stirling

1987-01-01

97

Neutron scattering study of elementary excitations in liquid helium-3  

Microsoft Academic Search

The neutron inelastic scattering function of liquid helium-3 at 0.015 K has been measured for wave vectors in the range 0.8 A⁻¹< or =q< or =2.2 A⁻¹. For q<1.4 A⁻¹, the scattering function contains two peaks. The peak at lower energy is due to spin-fluctuation scattering in the particle-hole region while the peak at higher energy is identified to be

K. Skold; C. A. Pelizzari; R. Kleb; G. E. Ostrowski

1976-01-01

98

Fractal Structure of the Acoustic Signal Excited in a Liquid by an Unstable Laser Radiation  

NASA Astrophysics Data System (ADS)

Thermooptical excitation of sound in a liquid by a laser radiation with a harmonically modulated intensity randomly distributed over the beam cross-section is considered. The processes are considered to be statistically homogeneous. It is assumed that the spatial spectrum of the intensity fluctuations in a laser beam is described by a power (fractal) law. It is demonstrated that the acoustic field in a liquid has a fractal structure.

Lyamshev, M. L.

2000-07-01

99

Junctions of multiple quantum wires with different Luttinger parameters  

NASA Astrophysics Data System (ADS)

Within the framework of boundary conformal field theory, we evaluate the conductance of stable fixed points of junctions of two and three quantum wires with different Luttinger parameters. For two wires, the physical properties are governed by a single effective Luttinger parameter for each of the charge and spin sectors. We present numerical density-matrix-renormalization-group calculations of the conductance of a junction of two chains of interacting spinless fermions with different interaction strengths, obtained using a recently developed method [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.105.226803 105, 226803 (2010)]. The numerical results show very good agreement with the analytical predictions. For three spinless wires (i.e., a Y junction) we analytically determine the full phase diagram and compute all fixed-point conductances as a function of the three Luttinger parameters.

Hou, Chang-Yu; Rahmani, Armin; Feiguin, Adrian E.; Chamon, Claudio

2012-08-01

100

Slosh wave and geyser excitations due to liquid hydrogen shut-off during draining in microgravity  

NASA Astrophysics Data System (ADS)

The dynamical behavior of liquid hydrogen shut-off during draining, and shut-off at the moment of the incipience of a suction dip have been investigated. It shows that a large amplitude surge is observed for liquid in the container at the moment of liquid hydrogen shut-off in reduced gravity. It also shows that slosh waves accompanied by a strong geyser are developed for surge-related flow fields induced by liquid hydrogen shut-off at the incipience of a suction dip. In the slosh wave excitation, both a lower gravity environment and higher flow rate before the shut-off of liquid draining are resonsible for the initiation of greater amplitude slosh waves. Slosh wave excitation, due to shut-off during liquid hydrogen draining, shift the fluid mass distribution in the container which imposes time-dependent variation in the spacecraft moment of inertia. This provides important information necessary for on-orbit guidance and attitude control of spacecraft.

Hung, R. J.; Shyu, K. L.

1995-04-01

101

Excited level anisotropy produced by ion-solid and ion-liquid surface interactions  

E-print Network

+ 1) an3 subscript de- notes the J for each energy level. . . . 1 1 The intensity of the Pl - D~ transition near 3451K of BII excited by a solrd gallium target at room temperature. ~ , , ~ , 30 1 1 The intensity of the p - D transition near 3451... R of BII excited hy' a liquid gallium target at 40 C 32 12 Comparison of the relative polarization fraction results for the aluminum, carbon, sijican, and gallium target INTRODUCTION When fast atoms collide with a gas, or pass through a foil...

Lee, Chin Shuang

2012-06-07

102

Excitation of Capillary Waves in Strongly Absorbing Liquids by a Modulated Laser Beam  

NASA Astrophysics Data System (ADS)

Several mechanisms for the excitation of capillary waves and for the development of the average deformation of a liquid surface under the action of a modulated laser beam are considered. The amplitude of the capillary wave in a strongly absorbing solution of the dye LDS 751 in ethylene glycol is experimentally studied as a function of laser intensity. Consecutive changes in the predominant mechanism of the excitation with increasing laser intensity are observed and described. At low laser intensities the mechanism connected with the creation of a surface tension gradient prevails. This mechanism becomes nonlinear with increasing influence of the convective motion. In addition, pressure pulsations of the convective flow start to contribute significantly to the generation process. The resonances of capillary waves in a cylindrical container are also investigated and used for determining the surface tension and viscosity of the liquid.

Kolomenskii, Alexandre A.; Schuessler, Hans A.

1999-10-01

103

Excitation of high energy levels under laser exposure of suspensions of nanoparticles in liquids  

NASA Astrophysics Data System (ADS)

Laser exposure of suspensions of nanoparticles in liquids leads to excitation of high energy levels in both liquid and nanoparticle material. The emission spectrum of the colloidal solution under exposure of a suspension metallic nanoparticles in water to radiation of a Nd:YAG laser of a picosecond range of pulse duration is discussed. Excitation of nuclear energy levels and neutron release is experimentally studied on the model system of transmutation of Hg into Au that occurs under exposure of Hg nanodrops suspended in D 2O. The proposed mechanism involves: (i) emission of X-ray photons by Hg nanoparticles upon laser exposure, leading to neutron release from D 2O, (ii) initiation of Hg ? Au transmutation by the capture of neutrons. The effect of transmutation is more pronounced using 196Hg isotope instead of Hg of natural isotope composition. The influence of laser pulse duration on the degree of transmutation (from fs through ns range) is discussed.

Shafeev, G. A.; Simakin, A. V.; Bozon-Verduraz, F.; Robert, M.

2007-12-01

104

Self-Consistent Model of Roton Cluster Excitations in Liquid Helium II  

E-print Network

We have proposed a model of roton cluster excitations in liquid helium~II based on a Schr\\"odinger-type equation with a self-consistent confining potential. We have derived an equation for the number of atoms in roton excitations, which can be treated as quantum $3{\\rm D}$ solitons, depending on vibrational quantum numbers. It is shown that the smallest roton cluster is in the symmetric vibrational quantum state and consists of 13 helium atoms. We have also used a modified Born approximation to calculate the $s$-scattering length for helium atoms. This allows us to calculate all parameters of Landau's roton excitation spectrum, in agreement to high accuracy with experimental measurements from neutron scattering.

V. I. Kruglov; M. J. Collett

2006-05-18

105

Similarity rules in gravity jitter-related spacecraft liquid propellant slosh waves excitation  

NASA Technical Reports Server (NTRS)

The dynamical behavior of fluids, in particular the effect of surface tension on partially filled rotating fluids in a full-scale prototype Gravity Probe-B Spacecraft propellant tank and various 10 percent subscale containers with identical values of similarity parameters such as Bond number, dynamical capillary number, rotational Reynolds number, and Weber number, as well as imposed gravity jitters have been investigated. It is shown that the Bond number can be used to simulate the wave characteristics of slosh wave excitation, whereas the Weber number can be used to simulate the wave amplitude of slosh-mode excitation. It is shown that a dynamical capillary number can be used to simulate the induced perturbation of the fluid stress distribution exerted on the wall. This distribution is governed by the interaction between surface tension (slosh-wave excitation along the liquid-vapor interface) and viscous (fluid stress exerted on the wall) forces.

Hung, R. J.; Lee, C. C.; Leslie, F. W.

1992-01-01

106

Chaos of liquid surface waves in a vessel under vertical excitation with slowly modulated amplitude  

Microsoft Academic Search

Free surface waves in a cylinder of liquid under vertical excitation with slowly modulated amplitude are investigated in the\\u000a current paper. It is shown by both theoretical analysis and numerical simulation that chaos may occur even for a single mode\\u000a with modulation which can be used to explain Gollub and Meyer's experiment. The implied resonant mechanism accounting for\\u000a this phenomenon

He Guowei; Li Jiachun

1997-01-01

107

On the universal relations for the prefactors in correlation functions of 1D quantum liquids  

E-print Network

For various one-dimensional quantum liquids in the framework of the Luttinger model (bosonization) we establish the relations between the coefficients before the power-law asymptotics of the correlators (prefactors) and the formfactors of the corresponding local operators. The derivation of these relations in the framework of the bosonization procedure allows to substantiate the prediction for the formfactors corresponding to the low-lying particle-hole excitations. We also obtain the formulas for the summation over the particle-hole states corresponding to the power-law asymptotics of the correlators.

A. A. Ovchinnikov

2011-05-29

108

Excitation spectrum of the vapor-liquid sup 4 He interface  

SciTech Connect

We analyze the elementary excitations in a vapor-liquid {sup 4}He interface with planar symmetry under saturation conditions. They are characterized by a momentum {h bar}{bold q} parallel to the interface plane and may be described by bound or continuum states. The wave functions of bound states are confined to the interface region. The continuum states may be described by their properties in the asymptotic region far apart from the interface layer. There, they are representing plane waves with momentum {h bar}{bold q}{sub {ital L}} and/or {h bar}{bold q}{sub {ital V}} vertical to the interface plane. The dispersion of these waves is determined by the energy-momentum relation in bulk liquid or vapor {sup 4}He. We may distinguish liquid, vapor, or vapor-liquid continuum states. The wave functions and energies are numerically evaluated in a generalized Feynman approximation, at various temperatures, 0{le}{ital T}{le}2 K. At nonvanishing temperatures, the wave functions of bound states represent rotons with wave number {ital q}{congruent}{ital q}{sub {ital R}}=1.8 A {sup {minus}1} trapped in the interface layer. At zero temperature, bound states appear at any wave number 0.2 A {sup {minus}1}{le}{ital q}{le}{ital q}{sub {ital R}} describing excitations of the free {sup 4}He surface. At temperatures 0{lt}{ital T}{le}1.5 K, the numerical results show that there are resonant vapor continuum states that have a very small amplitude in the asymptotic vapor region but develop an anomalously large amplitude in the interface layer. Our results on the excitation energies and on the corresponding wave functions in the interface region are displayed in a series of figures and are discussed in detail.

Gernoth, K.A.; Ristig, M.L. (Institut fuer Theoretische Physik, Universitaet zu Koeln, D-5000 Koeln 41 (Germany))

1992-02-01

109

The Kohn-Luttinger superconductivity in idealized doped graphene  

NASA Astrophysics Data System (ADS)

Idealized graphene monolayer is considered neglecting the van der Waals potential of the substrate and the role of the nonmagnetic impurities. The effect of the long-range Coulomb repulsion in an ensemble of Dirac fermions on the formation of the superconducting pairing in a monolayer is studied in the framework of the Kohn-Luttinger mechanism. The electronic structure of graphene is described in the strong coupling Wannier representation on the hexagonal lattice. We use the Shubin-Vonsowsky model which takes into account the intra- and intersite Coulomb repulsions of electrons. The Cooper instability is established by solving the Bethe-Salpeter integral equation, in which the role of the effective interaction is played by the renormalized scattering amplitude. The renormalized amplitude contains the Kohn-Luttinger polarization contributions up to and including the second-order terms in the Coulomb repulsion. We construct the superconductive phase diagram for the idealized graphene monolayer and show that the Kohn-Luttinger renormalizations and the intersite Coulomb repulsion significantly affect the interplay between the superconducting phases with f-, d+id-, and p+ip-wave symmetries of the order parameter.

Kagan, M. Yu.; Val'kov, V. V.; Mitskan, V. A.; Korovushkin, M. M.

2014-06-01

110

Charge accumulation on a Luttinger liquid Jason Alicea,* Cristina Bena,  

E-print Network

of metallic single-walled carbon nano- tubes has been shown to depend strongly on the nature of the contacts a nano- tube connected to metallic leads, while a gate voltage applied to a third electrode acts, 126801 2002 of a four-electron periodicity for electron addition in single-walled carbon nanotubes. DOI

111

Absence of Luttinger's Theorem due to Zeros in the Single-Particle Green Function  

E-print Network

We show exactly with an SU(N) interacting model that even if the ambiguity associated with the placement of the chemical potential, $\\mu$, for a T=0 gapped system is removed by using the unique value $\\mu(T\\rightarrow 0)$, Luttinger's sum rule is violated even if the ground-state degeneracy is lifted by an infinitesimal hopping. The failure stems from the non-existence of the Luttinger-Ward functional for a system in which the self-energy diverges. Since it is the existence of the Luttinger-Ward functional that is the basis for Luttinger's theorem which relates the charge density to sign changes of the single-particle Green function, no such theorem exists. Experimental data on the cuprates are presented which show a systematic deviation from the Luttinger count, implying a breakdown of the electron quasiparticle picture in strongly correlated electron matter.

Kiaran B. Dave; Philip W. Phillips; Charles L. Kane

2012-07-17

112

Absence of Luttinger's theorem due to zeros in the single-particle Green function.  

PubMed

We show exactly with an SU(N) interacting model that even if the ambiguity associated with the placement of the chemical potential, ?, for a T=0 gapped system is removed by using the unique value ?(T?0), Luttinger's sum rule is violated even if the ground-state degeneracy is lifted by an infinitesimal hopping. The failure stems from the nonexistence of the Luttinger-Ward functional for a system in which the self-energy diverges. Since it is the existence of the Luttinger-Ward functional that is the basis for Luttinger's theorem which relates the charge density to sign changes of the single-particle Green function, no such theorem exists. Experimental data on the cuprates are presented which show a systematic deviation from the Luttinger count, implying a breakdown of the electron quasiparticle picture in strongly correlated electron matter. PMID:23496693

Dave, Kiaran B; Phillips, Philip W; Kane, Charles L

2013-03-01

113

Excitation of finite-amplitude waves on the surface of a perfectly conducting liquid by a varying magnetic field  

SciTech Connect

The study of the behavior of a free surface of a liquid under simultaneous action of gravity forces and other, e.g., electromagnetic fields, leads to a number of interesting effects. Thus, it was shown (1) that a homogeneous varying electric field can excite finite-amplitude standing waves on the surface of the liquid. Similar effects are also possible under the action of magnetic fields. The effect of constant magnetic fields on the free surface of a liquid was investigated in (2, 3). Excitation of surface waves by a traveling magnetic field in a nonelectrically conducting magnetized liquid was studied in (4) in the linear approximation in the oscillation amplitude, while the wave effect on the field was not accounted for.

Nesterov, A.V.

1982-10-01

114

Semiclassical Time Evolution of the Holes from Luttinger Hamiltonian  

SciTech Connect

We study the semi-classical motion of holes by exact numerical solution of the Luttinger model. The trajectories obtained for the heavy and light holes agree well with the higher order corrections to the abelian and the non-abelian adiabatic theories in Ref. [1] [S. Murakami et al., Science 301, 1378 (2003)], respectively. It is found that the hole trajectories contain rapid oscillations reminiscent of the 'Zitterbewegung' of relativistic electrons. We also comment on the non-conservation of helicity of the light holes.

Jiang, Z.F.; /Beijing, Inst. Phys.; Li, R.D.; /Peking U.; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.; Liu1, W.M.; /Beijing, Inst. Phys.

2010-02-15

115

Pressure on the free surface of a liquid film from confined thermally excited sound waves  

NASA Astrophysics Data System (ADS)

Recently an acoustic destabilizing pressure was predicted, which could be shown experimentally via a dewetting pattern in thin polymer films. The wavelength ? of the fastest growing mode is a signature of the acting forces. Even in cases with stabilizing van der Waals forces, films became unstable. The present paper also considers thermally excited acoustic waves confined in a thin liquid film of thickness d. A new concept is developed to calculate the acoustic pressure for different boundary conditions: the free-standing film, the film rigid at one surface and the film deposited on a substrate, liquid or solid. For characteristic examples the calculation is carried out numerically. The results for the limiting cases are simple. The acoustic pressure of the free-standing film grows monotonically with d up to a level strongly depending on the temperature, it cannot destabilize the film. The acoustic pressure of the film rigid at one surface rapidly grows with d to a maximum and then decreases monotonically to the same level as for the free-standing film. On the right side of the maximum the film is unstable and ? grows quadratically with d, similar to the case of a destabilizing van der Waals pressure. For a film deposited on a substrate the acoustic pressure comes to a smaller level directly, depending on the excess sound velocity in the substrate: generally it yields a rather linear dependence of ? on d.

Hotz, R.

2008-11-01

116

Excitation of convective motions and surface hydrodynamic soliton-type waves in liquid crystals by a Gaussian laser beam  

SciTech Connect

The possibility of exciting convective motions with a toroidal symmetry in a disordered liquid-crystal cell with an open surface, which is locally heated by a Gaussian laser beam, is demonstrated experimentally. A perturbation of the free surface of the liquid crystal and a convective hydrodynamic motion are determined by temperature gradients. It is shown that a radial distribution of the director of a nematic liquid crystal appears in the convection region. Under certain experimental conditions, soliton-type hydrodynamic orientation waves are observed at the free surface of a nematic liquid crystal. It is found experimentally that the velocity of these waves is determined solely by the liquid-crystal parameters and is independent of the incident laser-radiation power. (interaction of laser radiation with matter. laser plasma)

Akopyan, R S; Alaverdyan, R B; Arakelyan, A G; Nersisyan, S Ts; Chilingaryan, Yu S [Department of Physics, Yerevan State University, Yerevan (Armenia)

2004-03-31

117

X-ray study of the liquid potassium surface: Structure and capillary wave excitations Oleg Shpyrko, Patrick Huber, Alexei Grigoriev, and Peter Pershan  

E-print Network

X-ray study of the liquid potassium surface: Structure and capillary wave excitations Oleg Shpyrko the liquid surface of pure potassium. They strongly suggest the existence of atomic layering at the free surface of a pure liquid metal with low surface tension. Prior to this study, layering was observed only

Grigoriev, Alexei

118

Field theory renormalization group: the Tomonaga Luttinger model revisited  

NASA Astrophysics Data System (ADS)

We apply field theoretical renormalization group (RG) methods to describe the Tomonaga-Luttinger model as an important test ground to deal with spin-charge separation effects in higher spatial dimensions. We calculate the RG equations for the renormalized forward couplings g2R and g4R up to two-loop order and demonstrate that they do not flow in the vicinities of the Fermi points (FPs). We solve the Callan-Symanzik equation for G(a)R in the vicinities of the FPs. We calculate the related spectral function and the momentum distribution function at p = kF, p0 = ?. We compute the renormalized one-particle irreducible function ?(2)(+)R(p, p0 = 0; ?) and show that it carries important spin-charge separation effects in agreement with well-known results. Finally, we discuss the implementation of the RG scheme taking into account the important simplifications produced by the Ward identities.

Ferraz, A.

2006-06-01

119

Inelastic electron and Raman scattering from the collective excitations in quantum wires: Zero magnetic field  

NASA Astrophysics Data System (ADS)

The nanofabrication technology has taught us that an m-dimensional confining potential imposed upon an n-dimensional electron gas paves the way to a quasi-(n-m)-dimensional electron gas, with m ? n and 1 ? n, m ? 3. This is the road to the (semiconducting) quasi-n dimensional electron gas systems we have been happily traversing on now for almost two decades. Achieving quasi-one dimensional electron gas (Q-1DEG) [or quantum wire(s) for more practical purposes] led us to some mixed moments in this journey: while the reduced phase space for the scattering led us believe in the route to the faster electron devices, the proximity to the 1D systems left us in the dilemma of describing it as a Fermi liquid or as a Luttinger liquid. No one had ever suspected the potential of the former, but it took quite a while for some to convince the others on the latter. A realistic Q-1DEG system at the low temperatures is best describable as a Fermi liquid rather than as a Luttinger liquid. In the language of condensed matter physics, a critical scrutiny of Q-1DEG systems has provided us with a host of exotic (electronic, optical, and transport) phenomena unseen in their higher- or lower-dimensional counterparts. This has motivated us to undertake a systematic investigation of the inelastic electron scattering (IES) and the inelastic light scattering (ILS) from the elementary electronic excitations in quantum wires. We begin with the Kubo's correlation functions to derive the generalized dielectric function, the inverse dielectric function, and the Dyson equation for the dynamic screened potential in the framework of Bohm-Pines' random-phase approximation. These fundamental tools then lead us to develop methodically the theory of IES and ILS for the Q-1DEG systems. As an application of the general formal results, which know no bounds regarding the subband occupancy, we compute the density of states, the Fermi energy, the full excitation spectrum [comprised of intrasubband and intersubband single-particle as well as collective excitations], the loss functions for the IES and the Raman intensity for the ILS. We observe that it is the collective (plasmon) excitations that largely contribute to the predominant peaks in the energy-loss and the Raman spectra. The inductive reasoning is that the IES can be a potential alternative of the overused ILS for investigating collective excitations in quantum wires. We trust that this research work shall be useful to all - from novice to expert and from theorist to experimentalist - who believe in the power of traditional science.

Kushwaha, Manvir S.

2013-04-01

120

Excitations are localized and relaxation is hierarchical in glass-forming liquids  

NASA Astrophysics Data System (ADS)

For several atomistic models of glass formers, at conditions below their glassy dynamics onset temperatures, To, we use importance sampling of trajectory space to study the structure, statistics and dynamics of excitations responsible for structural relaxation. Excitations are detected in terms of persistent particle displacements of length a. At supercooled conditions, for a of the order of or smaller than a particle diameter, we find that excitations are associated with correlated particle motions that are sparse and localized, occupying a volume with an average radius that is temperature independent and no larger than a few particle diameters. We show that the statistics and dynamics of these excitations are facilitated and hierarchical. Excitation energy scales grow logarithmically with a. Excitations at one point in space facilitate the birth and death of excitations at neighboring locations, and space-time excitation structures are microcosms of heterogeneous dynamics at larger scales. This nature of dynamics becomes increasingly dominant as temperature T is lowered. We show that slowing of dynamics upon decreasing temperature below To is the result of a decreasing concentration of excitations and concomitant growing hierarchical leng

Keys, Aaron; Hedges, Lester; Garrahan, Juan; Glotzer, Sharon; Chandler, David

2012-02-01

121

Cryogenic exciter  

DOEpatents

The disclosed technology is a cryogenic static exciter. The cryogenic static exciter is connected to a synchronous electric machine that has a field winding. The synchronous electric machine is cooled via a refrigerator or cryogen like liquid nitrogen. The static exciter is in communication with the field winding and is operating at ambient temperature. The static exciter receives cooling from a refrigerator or cryogen source, which may also service the synchronous machine, to selected areas of the static exciter and the cooling selectively reduces the operating temperature of the selected areas of the static exciter.

Bray, James William (Niskayuna, NY); Garces, Luis Jose (Niskayuna, NY)

2012-03-13

122

Sloshing response of nonuniform density liquid in a laterally excited tank  

SciTech Connect

A large number of high level waste (HLW) storage tanks at various facilities contain liquid with nonuniformity density. Exploratory studies show that the dynamic response of a tank containing two liquids is quite different from that of an identical tank containing only one liquid. To design and evaluate the HLW storage tanks it is necessary to understand the sloshing response of tanks that contain liquid with nonuniform density. The system considered is a circular cylindrical tank containing a liquid whose density increases with the liquid depth. The density distribution along the depth can be of any arbitrary continuous function. In the analysis, the liquid field is divided into n layers. The thicknesses of the liquid layers can be different, but the density of each liquid layer is considered to be uniform and its value is assigned to be the value of the original liquid density at the mid-height of that layer. The problem is solved by the transfer matrix technique. The effect of the nonuniform liquid density on the sloshing response is illustrated in a numerical example in which the linear and cosine distributions of the liquid density are assumed. The response functions examined include the sloshing frequencies, surface wave height, and the associated convective hydrodynamic pressure. The results are presented in tabular and graphical forms. It is found that the natural frequencies of the sloshing motion for nonuniform density liquid are lower than those of the uniform density liquid of the same total depth contained in an identical tank. Also, it is shown that for nonuniform density liquid, the maximum sloshing wave height may increase significantly and the magnitude of the convective hydrodynamic pressure may be quite different compared with that of a uniform liquid contained in an identical tank.

Tang, Y.; Chang, Y.W.

1993-10-01

123

Liquid settlement, resettlement, slosh wave excitation and geyser motion during during reorientation in microgravity  

Microsoft Academic Search

A key objective of cryogenic fluid management of the spacecraft propulsion system is to develop the technology necessary for acquisition or positioning of liquid and vapor within a tank in reduced gravity to enable liquid outflow or vapor venting. Resettlement or reorientation of liquid propellant can be accomplished by providing the optimal impulsive acceleration to the spacecraft such that the

R. J. Hung; K. L. Shyu

1993-01-01

124

Excitations Are Localized and Relaxation Is Hierarchical in Glass-Forming Liquids  

NASA Astrophysics Data System (ADS)

For several atomistic models of glass formers, at conditions below their glassy-dynamics-onset temperatures, To, we use importance sampling of trajectory space to study the structure, statistics, and dynamics of excitations responsible for structural relaxation. Excitations are detected in terms of persistent particle displacements of length a. At supercooled conditions, for a of the order of or smaller than a particle diameter, we find that excitations are associated with correlated particle motions that are sparse and localized, occupying a volume with an average radius that is temperature-independent and no larger than a few particle diameters. We show that the statistics and dynamics of these excitations are facilitated and hierarchical. Excitation-energy scales grow logarithmically with a. Excitations at one point in space facilitate the birth and death of excitations at neighboring locations, and space-time excitation structures are microcosms of heterogeneous dynamics at larger scales. This nature of dynamics becomes increasingly dominant as temperature T is lowered. We show that slowing of dynamics upon decreasing temperature below To is the result of a decreasing concentration of excitations and concomitantly growing length scales for dynamical correlations that develop in a hierarchical manner, and further that the structural-relaxation time ? follows the parabolic law, log?(?/?o)=J2(1/T-1/To)2, for T

Keys, Aaron S.; Hedges, Lester O.; Garrahan, Juan P.; Glotzer, Sharon C.; Chandler, David

2011-10-01

125

Excitation energies and ionization potentials at high electric fields for molecules relevant for electrically insulating liquids  

NASA Astrophysics Data System (ADS)

The electric-field dependence of the molecular ionization potential and excitation energies is investigated by density-functional theory calculations. It is demonstrated that the ionization potential has a strong field dependence and decreases with increasing field. The excitation energies depend weakly on the field and the number of available excited states decreases with increasing field since the ionization potential has a stronger field dependence. Above a specific field, different for each molecule, a two-state model is obtained consisting of the electronic ground state and the ionized state. Implications for streamer propagation and electrically insulating materials are discussed.

Davari, N.; Åstrand, P.-O.; Ingebrigtsen, S.; Unge, M.

2013-04-01

126

Luttinger-field approach to thermoelectric transport in nanoscale conductors  

NASA Astrophysics Data System (ADS)

Thermoelectric transport in nanoscale conductors is analyzed in terms of the response of the system to a thermomechanical field, first introduced by Luttinger, which couples to the electronic energy density. While in this approach, the temperature remains spatially uniform, we show that a spatially varying thermomechanical field effectively simulates a temperature gradient across the system and allows us to calculate the electric and thermal currents that flow due to the thermomechanical field. In particular, we show that in the long-time limit, the currents thus calculated reduce to those that one obtains from the Landauer-Büttiker formula, suitably generalized to allow for different temperatures in the reservoirs, if the thermomechanical field is applied to prepare the system, and subsequently turned off at t =0. Alternatively, we can drive the system out of equilibrium by switching the thermomechanical field after the initial preparation. We compare these two scenarios, employing a model noninteracting Hamiltonian, in the linear regime, in which they coincide, and in the nonlinear regime, in which they show marked differences. We also show how an operationally defined local effective temperature can be computed within this formalism.

Eich, F. G.; Principi, A.; Di Ventra, M.; Vignale, G.

2014-09-01

127

Destruction of liquid and gaseous waste surrogates in an acoustically excited dump combustor  

Microsoft Academic Search

Destruction of gaseous and liquid waste surrogates is studied in a two-dimensional dump combustor configuration. Two different waste surrogates are examined: sulfur hexafluoride, which is injected in the gaseous phase and pyrolyzed at high temperatures, and acetonitrile, which is injected in the liquid phase and can be burned in the presence of high concentrations of oxidizing species. Waste surrogates are

J. W. Willis; C. Cadou; M. Mitchell; A. R. Karagozian; O. I. Smith

1994-01-01

128

Thermally excited liquid surface waves and their study through the quasielastic scattering of light  

Microsoft Academic Search

A simple apparatus employing a semiconductor diode laser and PIN photodiode has been used to investigate thermal capillary waves on liquid surfaces. These waves act as a weak, time-varying diffraction grating for the incident laser light; the diffracted light can be heterodyned with the light directly reflected from the liquid surface to extract fluid properties (surface tension and viscosity). In

W. M. Klipstein; J. S. Radnich; S. K. Lamoreaux

1996-01-01

129

The fluorescence action spectra of some saturated hydrocarbon liquids for excitation energies above and below their ionization thresholds  

SciTech Connect

Fluorescence action spectra have been obtained for the neat liquids, [ital cis]-decalin, [ital trans]-decalin, bicyclohexyl, cyclohexane, methylcyclohexane, isobutylcyclohexane, 2,3,4-trimethylpentane, 2,3-dimethylbutane, 3-methylhexane, 3-methylpentane, [ital n]-decane, [ital n]-dodecane, and [ital n]-pentadecane at excitation energies, [epsilon], ranging from their absorption onsets (at ca. 7 eV) to 10.3 eV. For all compounds, with the exception of [ital cis]-decalin, the fluorescence quantum yield is observed to monotonically decline with increasing [epsilon], reaching a minimum value at an energy, [epsilon][sub [ital m

Ostafin, A.E.; Lipsky, S. (Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455 (United States))

1993-04-01

130

Three-dimensional spacecraft angular momentum fluctuations due to gravity jitter excited slosh waves in liquid propellant system  

NASA Technical Reports Server (NTRS)

The paper investigates the dynamical behavior of fluids affected by asymmetric gravity jitter oscillations, in particular the effect of surface tension on partially filled rotating fluids (cryogenic liquid helium and helium vapor) in a subscale Gravity Probe-B spacecraft propellant dewar tank imposed by time-dependent variation in the direction of the background gravity environment. It is shown that lower frequency gravity jitter imposed on the time-dependent variation in the direction of background gravity induced a greater amplitude of oscillations and a stronger degree of asymmetry in liquid-vapor interface geometry than that made by the higher frequency gravity jitter. Fluctuations of angular momentum and spacecraft moment caused by slosh wave excitation are also studied. Slosh-wave-induced fluctuations in angular momentum and moment are important factors in spacecraft dynamics, guidance, and attitude controls.

Hung, R. J.; Pan, H. L.; Leslie, F. W.

1992-01-01

131

Minimal-excitation states for electron quantum optics using levitons  

NASA Astrophysics Data System (ADS)

The on-demand generation of pure quantum excitations is important for the operation of quantum systems, but it is particularly difficult for a system of fermions. This is because any perturbation affects all states below the Fermi energy, resulting in a complex superposition of particle and hole excitations. However, it was predicted nearly 20 years ago that a Lorentzian time-dependent potential with quantized flux generates a minimal excitation with only one particle and no hole. Here we report that such quasiparticles (hereafter termed levitons) can be generated on demand in a conductor by applying voltage pulses to a contact. Partitioning the excitations with an electronic beam splitter generates a current noise that we use to measure their number. Minimal-excitation states are observed for Lorentzian pulses, whereas for other pulse shapes there are significant contributions from holes. Further identification of levitons is provided in the energy domain with shot-noise spectroscopy, and in the time domain with electronic Hong-Ou-Mandel noise correlations. The latter, obtained by colliding synchronized levitons on a beam splitter, exemplifies the potential use of levitons for quantum information: using linear electron quantum optics in ballistic conductors, it is possible to imagine flying-qubit operation in which the Fermi statistics are exploited to entangle synchronized electrons emitted by distinct sources. Compared with electron sources based on quantum dots, the generation of levitons does not require delicate nanolithography, considerably simplifying the circuitry for scalability. Levitons are not limited to carrying a single charge, and so in a broader context n-particle levitons could find application in the study of full electron counting statistics. But they can also carry a fraction of charge if they are implemented in Luttinger liquids or in fractional quantum Hall edge channels; this allows the study of Abelian and non-Abelian quasiparticles in the time domain. Finally, the generation technique could be applied to cold atomic gases, leading to the possibility of atomic levitons.

Dubois, J.; Jullien, T.; Portier, F.; Roche, P.; Cavanna, A.; Jin, Y.; Wegscheider, W.; Roulleau, P.; Glattli, D. C.

2013-10-01

132

Thermocapillary flow excited by focused nanosecond laser pulses in contaminated thin liquid iron films  

NASA Astrophysics Data System (ADS)

A new method is established to determine surface tension and mechanisms of evaporation of liquid metals in a wide range of high temperatures. It is based on a combination of high-speed transmission electron microscopy imaging of flow in nanosecond laser pulse molten films and computer simulation. The technique was applied to iron films with native oxides to investigate the effects of surface active impurities in a melt with transient temperatures and gradients up to 4000 K and 5×108 K/m, respectively. Such melts show a shear flow with direction changing once or twice during 1-2 ?s after a 20 ns laser pulse, which cannot be simulated using table values for the temperature coefficient of the surface tension and the vapor pressure. Instead, evaporation is negligible, and the flow of the liquid is mainly driven by a fast changing gradient of the surface tension caused by a time-varying distribution of temperature and dissolved surface active oxygen atoms. Current site coverage models, giving the surface tension as function of temperature and impurity content for static liquids, successfully can be applied to liquids moving on the nanosecond/micrometer scale, too. However, the number of active surface sites can be vastly reduced by short-lived oxide covers, e.g., in iron with native oxides down to 3.5% of the total number of surface sites.

Balandin, V. Yu.; Otte, D.; Bostanjoglo, O.

1995-08-01

133

Raman spectroscopy of a coal liquid shows that fluorescence interference is minimized with ultraviolet excitation  

Microsoft Academic Search

The first ultraviolet resonance Raman measurements of a coal liquid are reported. The spectra detail the presence of numerous polycyclic aromatic hydrocarbons with ring systems similar to those of naphthalene, fluorene, phenanthrene, pyrene, and triphenylene . The ultraviolet resonance Raman measurements of this highly complex sample show no significant interference from fluorescence. The lack of fluorescence interference and the high

S. A. Asher; C. R. Johnson

1984-01-01

134

Raman Spectroscopy of a Coal Liquid Shows that Fluorescence Interference is Minimized with Ultraviolet Excitation  

Microsoft Academic Search

The first ultraviolet resonance Raman measurements of a coal liquid are reported. The spectra detail the presence of numerous polycyclic aromatic hydrocarbons with ring systems similar to those of naphthalene, fluorene, phenanthrene, pyrene, and triphenylene. The ultraviolet resonance Raman measurements of this highly complex sample show no significant interference from fluorescence. The lack of fluorescence interference and the high selectivity

Sanford A. Asher; Craig R. Johnson

1984-01-01

135

Thermally excited capillary waves at vapor/liquid interfaces of water-alcohol mixtures  

E-print Network

The density profiles of liquid/vapor interfaces of water-alcohol (methanol, ethanol and propanol) mixtures were studied by surface sensitive synchrotron X-ray scattering techniques. X-ray reflectivity and diffuse scattering measurements, from the pure and mixed liquids, were analyzed in the framework of capillary-wave theory to address the characteristics length-scales of the intrinsic roughness and the shortest capillary-wavelength (alternatively, the upper wave-vector cutoff in capillary wave theory). Our results establish that the intrinsic roughness is dominated by average interatomic distances. The extracted effective upper wave-vector cutoff indicates capillary wave theory breaks-down at distances on order of bulk correlation lengths.

David Vaknin; Wei Bu; Jaeho Sung; Yoonnam Jeon; Doseok Kim

2009-04-15

136

Photoconductivity induced by single-proton excitation of aromatic molecules in liquid hydrocarbons  

SciTech Connect

The spectral dependence of the photoconductivity of several aromatic solutes (anthracene, 1,2-benzanthracene, perylene, pyrene, azulene, ..cap alpha..-methylnaphthalene, and triphenylamine) in liquid hydrocarbon solvents (neopentane, 2,2,4-trimethylpentane(2,2,4-TMP), 2,2,4,4-tetramethylpentane (2,2,4,4-TMP), and n-pentane) are reported. In liquids which exhibit high thermal electron mobilities, relative maxima or shoulders are detected in the photoconductivity spectra. The corresponding transitions are thought to involve the formation of Rydberg states as precursors of separated charges. For anthracene and azulene, the transitions occur at approximately the same energy where Rydberg lines are observed in the gas phase. Quenching of the photoconductivity by perfluoromethylcyclohexane and by perfluoro-n-hexane supports this hypothesis.

Holroyd, R.A.; Preses, J.M.; Boettcher, E.H.; Schmidt, W.F.

1984-02-16

137

Raman spectroscopy of a coal liquid shows that fluorescence interference is minimized with ultraviolet excitation.  

PubMed

The first ultraviolet resonance Raman measurements of a coal liquid are reported. The spectra detail the presence of numerous polycyclic aromatic hydrocarbons with ring systems similar to those of naphthalene, fluorene, phenanthrene, pyrene, and triphenylene . The ultraviolet resonance Raman measurements of this highly complex sample show no significant interference from fluorescence. The lack of fluorescence interference and the high selectivity indicate that ultraviolet resonance Raman spectroscopy is a powerful new technique for characterizing highly complex samples and mixtures. PMID:6740313

Asher, S A; Johnson, C R

1984-07-20

138

Raman Spectroscopy of a Coal Liquid Shows that Fluorescence Interference is Minimized with Ultraviolet Excitation  

NASA Astrophysics Data System (ADS)

The first ultraviolet resonance Raman measurements of a coal liquid are reported. The spectra detail the presence of numerous polycyclic aromatic hydrocarbons with ring systems similar to those of naphthalene, fluorene, phenanthrene, pyrene, and triphenylene. The ultraviolet resonance Raman measurements of this highly complex sample show no significant interference from fluorescence. The lack of fluorescence interference and the high selectivity indicate that ultraviolet resonance Raman spectroscopy is a powerful new technique for characterizing highly complex samples and mixtures.

Asher, Sanford A.; Johnson, Craig R.

1984-07-01

139

Raman spectroscopy of a coal liquid shows that fluorescence interference is minimized with ultraviolet excitation  

SciTech Connect

The first ultraviolet resonance Raman measurements of a coal liquid are reported. The spectra detail the presence of numerous polycyclic aromatic hydrocarbons with ring systems similar to those of naphthalene, fluorene, phenanthrene, pyrene, and triphenylene. The ultraviolet resonance Raman measurements of this highly complex sample show no significant interference from fluorescence. The lack of fluorescence interference and the high selectivity indicate that ultraviolet resonance Raman spectroscopy is a powerful new technique for characterizing highly complex samples and mixtures. 11 references, 2 figures.

Asher, S.A.; Johnson, C.R.

1984-07-20

140

Raman spectroscopy of a coal liquid shows that fluorescence interference is minimized with ultraviolet excitation  

SciTech Connect

The first ultraviolet resonance Raman measurements of a coal liquid are reported. The spectra detail the presence of numerous polycyclic aromatic hydrocarbons with ring systems similar to those of naphthalene, fluorene, phenanthrene, pyrene, and triphenylene . The ultraviolet resonance Raman measurements of this highly complex sample show no significant interference from fluorescence. The lack of fluorescence interference and the high selectivity indicate that ultraviolet resonance Raman spectroscopy is a powerful new technique for characterizing highly complex samples and mixtures.

Asher, S.A.; Johnson, C.R.

1984-07-20

141

Properties of surface wave trains excited by mass transfer through a liquid surface  

Microsoft Academic Search

In annular containers, various traveling periodic surface wave trains are generated in liquid layers during the absorption process of a miscible surface-active substance out of the vapor phase. Single and counter-rotating wave trains are observed. We here report on waves found to be dispersion-free associated to mostly longitudinal, dilational surface-tension-gradient-driven motions. We report on interactions of the wave crests and

A. Wierschem; H. Linde; M. G. Velarde

2001-01-01

142

Electron photodetachment from iodide in ionic liquids through charge-transfer-to-solvent band excitation.  

PubMed

Solvation of iodide and electrons in an ionic liquid (N,N,N-trimethyl-n-propylammonium bis(trifluoromethanesulfonyl)imide; TMPA-TFSI) was studied through the absorption spectra of the charge-transfer-to-solvent (CTTS) state of iodide and of solvated electrons. The interaction between the TMPA cation and iodide was strong, whereas electrons were weakly solvated in TMPA-TFSI. We followed electron photodetachment from iodide to the ionic liquid and formation of the solvated electrons by observing absorption in the visible and near-infrared regions using a nanosecond laser flash photolysis method. The quantum yield of the photodetachment in TMPA-TFSI was estimated to be 0.34, which is much higher than that in a high-concentration aqueous salt solution previously reported. We also examined a reaction of the solvated electrons with the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (Bmim-TFSI) as a solute in TMPA-TFSI. The reaction rate was determined to be 5.3 x 10(8) M(-1) s(-1). The electrons before full solvation (dry electrons) reacted with Bmim cations efficiently. These observations suggest that the electrons in TMPA-TFSI can move easily before solvation. PMID:17474702

Katoh, Ryuzi; Yoshida, Yoichi; Katsumura, Yosuke; Takahashi, Kenji

2007-05-10

143

Gas phase ion formation from a liquid beam of arginine in aqueous solution by IR multiphoton excitation  

NASA Astrophysics Data System (ADS)

A liquid beam of aqueous solutions of arginine (AH), its hydrochloric acid salt (AH 2Cl) and its sodium salt (ANa) was irradiated with a pulsed IR laser at 3509 cm -1 (2.85 ?m). Positive and negative ions ejected to the gas phase were mass analyzed. From the AH 2Cl and the ANa aqueous solutions, the pre-existing ions in the solution were ejected directly to the gas phase. From the AH solution, on the other hand, both a protonated arginine ion, AH2+ and an argininate ion, A - were observed in the gas phase. Production of these ions is accounted for the four-photon excitation of water molecules in the solution.

Kohno, Jun-ya; Toyama, Namiki; Buntine, Mark A.; Mafuné, Fumitaka; Kondow, Tamotsu

2006-03-01

144

Magnetic excitations in Kondo liquid: superconductivity and hidden magnetic quantum critical fluctuations  

SciTech Connect

We report Knight shift experiments on the superconducting heavy electron material CeCoIn{sub 5} that allow one to track with some precision the behavior of the heavy electron Kondo liquid in the superconducting state with results in agreement with BCS theory. An analysis of the {sup 115}In nuclear quadrupole resonance (NQR) spin-lattice relaxation rate T{sub 1}{sup -1} measurements under pressure reveals the presence of 2d magnetic quantum critical fluctuations in the heavy electron component that are a promising candidate for the pairing mechanism in this material. Our results are consistent with an antiferromagnetic quantum critical point (QCP) located at slightly negative pressure in CeCoIn{sub 5} and provide additional evidence for significant similarities between the heavy electron materials and the high T{sub c} cuprates.

Yang, Yifeng [Los Alamos National Laboratory; Urbano, Ricardo [NHMFL, FL; Nicholas, Curro [UC DAVIS; Pines, David [UC DAVIS

2009-01-01

145

Numerical Study of the Spin-Hall Conductance in the Luttinger Model  

Microsoft Academic Search

We present first numerical studies of the disorder effect on the recently\\u000aproposed intrinsic spin Hall conductance in a three dimensional (3D) lattice\\u000aLuttinger model. The results show that the spin Hall conductance remains finite\\u000ain a wide range of disorder strength, with large fluctuations. The\\u000adisorder-configuration-averaged spin Hall conductance monotonically decreases\\u000awith the increase of disorder strength and vanishes

W. Q. Chen; Z. Y. Weng; D. N. Sheng

2005-01-01

146

Occupation numbers in strongly polarized Fermi gases and the Luttinger theorem  

E-print Network

We study a two-component Fermi gas that is so strongly polarized that it remains normal fluid at zero temperature. We calculate the occupation numbers within the particle-particle random-phase approximation, which is similar to the Nozieres-Schmitt-Rink approach. We show that the Luttinger theorem is fulfilled in this approach. We also study the change of the chemical potentials which allows us to extract, in the limit of extreme polarization, the polaron energy.

Michael Urban; Peter Schuck

2014-07-08

147

Occupation numbers in strongly polarized Fermi gases and the Luttinger theorem  

E-print Network

We study a two-component Fermi gas that is so strongly polarized that it remains normal fluid at zero temperature. We calculate the occupation numbers within the particle-particle random-phase approximation, which is similar to the Nozieres-Schmitt-Rink approach. We show that the Luttinger theorem is fulfilled in this approach. We also study the change of the chemical potentials which allows us to extract, in the limit of extreme polarization, the polaron energy.

Urban, Michael

2014-01-01

148

B{sub 2u} {yields} A{sub 1g} fluorescence excitation spectrum of liquid benzene from 250 to 150 nm  

SciTech Connect

The B{sub 2u} {yields} A{sub 1g} fluorescence quantum yield of benzene has been obtained for excitations from 250 to 150 nm in the solvents n-hexane, isooctane, n-perfluorohexane, n-pentane, cyclohexane, and cis-decalin. In n-hexane and isooctane, measurements have been made over a range of benzene concentrations from 0.11{sub 2} to 11.2 M (the neat liquid). In dilute solutions, the sudden losses in fluorescence as the excitation wavelength sweeps from the first into the second absorption system and then again as the excitation wavelength sweeps from the second into the third absorption system are correlated with the behavior of benzene vapor in the region of channel three. Increasing the benzene concentration causes abatements in the rate of loss of fluorescence with decreasing excitation wavelength in the regions of the second and third absorption systems and, above 2 M, causes a reversal of this rate so as to cause a recovery of the fluorescence in the region of the third absorption system. These changes are correlated with the effects of benzene concentration on the electronic absorption spectrum and with reported effects of clustering on the multiphoton photoionization efficiency. 59 refs., 13 figs.

Saik, V.O.; Lipsky, S. [Univ. of Minnesota, Minneapolis, MN (United States)

1995-06-29

149

Atomic-like behaviors and orbital-related Tomonaga-Luttinger liquid in carbon  

E-print Network

nanotubes (SWNTs) encapsulating a series of fullerenes, such as C60, C70, and Gd@C82 (C82encapsulating Gd influence of encapsulated C60 molecules on electron transport in carbon-nanotube peapod quantum dots. We that the encapsulated C60 molecules form doubly degenerate levels only at ground state in peapod quantum dots and do

Paris-Sud XI, Université de

150

Journal of Low Temperature Physics, Vol. 112, Nos. 3/4, 1998 Excitations of Liquid 4He in Disorder  

E-print Network

of the variance and correlation length of the resulting disordering environment. New weight in S(q, w) at low w (i in many porous media. To date, much interest has focused on understanding the phase diagram of disordered to gain insight into the effect of disorder on the excitation spectrum of a three-dimensional (3D) Bose

Glyde, Henry R.

151

Properties of bound, resonant, and regular continuum states of the excitation spectrum of symmetric liquid {sup 4}He films at {ital T}=0 K  

SciTech Connect

Elementary excitations in rather thick symmetric films of liquid {sup 4}He at {ital T}=0 K are investigated. They are characterized by a momentum {h_bar}{ital q} parallel to the surface and may be described by bound or continuum states, which are obtained by solving a Bogoliubov-type equation formulated within the framework of the paired-phonon analysis and the hypernetted-chain approximation. Films of coverages {ital n}{sub {ital c}}=0.3 and 0.4 A{sup {minus}2} confined by simple Gaussian potentials are studied. The excitation spectrum is numerically evaluated by discretizing the associated eigenvalue problem in a finite box. The evolution of the energy levels as a function of the box size is explored. Examples of the calculated energies and wave functions are displayed in a series of figures. Two differing sorts of continuum states may be distinguished. Depending on the behavior of their excitation energies as a function of the box size on the one hand, and the spatial distribution of their wave functions inside the film and in the asymptotic region far apart from the interface layer on the other, the continuum solutions can be separated into two classes of excitations: (a) the {open_quote}{open_quote}regular{close_quote}{close_quote} continuum states and (b) the {open_quote}{open_quote}resonant modes.{close_quote}{close_quote} The matrix elements of the particle-hole potential and the penetration factors of the most important states are examined. The lowest-lying branch of states is always bound and for {ital q}{lt}{ital q}{sub {ital R}} ({ital q}{sub {ital R}}{approx_equal}1.9 A{sup {minus}1} being the momentum at the roton minimum) it describes surface ripplon excitations. In the atomic scale regime, 1.1 A{sup {minus}1}{lt}{ital q}{lt}{ital q}{sub {ital R}}, the hardest {open_quote}{open_quote}resonant mode{close_quote}{close_quote} can be interpreted as a roton trapped at the center of the film and therefore associated with bulk excitations of the system.

Szybisz, L. [Laboratorio Tandem Argentino, Departamento de Fisica, Comision Nacional de Energia Atomica, Av. del Libertador 8250, RA-1429 Buenos Aires (Argentina)] [Laboratorio Tandem Argentino, Departamento de Fisica, Comision Nacional de Energia Atomica, Av. del Libertador 8250, RA-1429 Buenos Aires (Argentina); [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, RA-1428 Buenos Aires (Argentina)

1996-03-01

152

Formation of excited states of N,N,N',N'-tetramethyl-p-phenylenediamine in irradiated nonpolar liquids. [Electron beams  

SciTech Connect

The yield of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) excited states, G/sub s/, has been obtained in irradiated tetramethylsilane, isooctane, cyclopentane, n-hexane, and cyclohexane as a function of TMPD concentration, c, over the range c = 0.5 x 10/sup -3/-50 x 10/sup -3/ M. In tetramethylsilane and isooctane, G/sub s/ is found to be linear on c as would be expected on the basis of a nondiffusional transfer of the solvent ion positive charge to TMPD followed by recombination of TMPD/sup +/ with the geminate electron. In cyclopentane, n-hexane, and cyclohexane, G/sub s/ becomes increasingly concave downward in its depedence on c. This concavity is attributed to an increasing contribution to G/sub s/ from excited states of the solvent that nonradiatively transfer their energy to TMPD. Optical excitation of cyclohexane at 147 nm and measurement of the quenching of its fluorescence by TMPD confirm this view.

Choi, H.T.; Tweeten, D.W.; Lipsky, S.

1984-11-22

153

Surface tension measurement of liquid metal with inelastic light-scattering spectroscopy of a thermally excited capillary wave  

NASA Astrophysics Data System (ADS)

A new experimental configuration is introduced for simultaneous recording of Raman and laser-induced breakdown spectroscopy (LIBS) in a single spectrum. A laser pulse is divided into two beams by a Glan-Taylor prism. By focusing one beam to the sample surface, micro-plasma is created and LIBS signal is emitted. The other beam is directed to the same point of the sample, but does not focused. The scattered light due to the second laser beam is mixed with the plasma emission and is recorded in a single spectrum. Atomic and molecular spectra of some minerals and chemical samples are recorded by the mentioned setup. Due to the high-plasma quenching in liquids, LIBS signals are not detected for organic liquid samples, instead a strong stimulated Raman signal is appeared, and as a result, an overlay of ordinary Raman with stimulated Raman is observed.

Matroodi, F.; Tavassoli, S. H.

2014-10-01

154

Breakdown of the Fermi liquid due to long-range interactions  

SciTech Connect

Fermions interacting via a long-range repulsive potential are considered in [ital D] spatial dimensions, where 1[lt][ital D][le]2. The standard screening picture is found to break down, i.e., the screened effective interaction cannot be treated as instantaneous. For a bare potential which behaves at long distances as [ital r][sup [minus](2[minus][ital D])] [as ln [ital r] in two dimensions (2[ital D])] and within the random-phase approximation, the retardation effects induce an infrared catastrophe that changes the Fermi liquid into a Luttinger liquid in which the occupation number in momentum space is continuous across the Fermi surface. In 2D, the quantum liquid which we investigate may be called a [ital Z]=0 Fermi liquid'' (where [ital Z] is the strength of the quasiparticle pole at the Fermi surface) since the electron propagator has an isolated pole with a constant residue that scales to zero as the size of the system increases to infinity. For 1[lt][ital D][lt]2, the quantum liquid resembles the 1D Luttinger liquid as the single-particle propagator exhibits a branch cut structure. Moreover, we present a ground-state wave function which reproduces the Luttinger-liquid exponent of the momentum distribution near the Fermi surface.

Bares, P.; Wen, X. (Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States))

1993-09-15

155

Optical and application study of gas-liquid discharge excited by bipolar nanosecond pulse in atmospheric air.  

PubMed

In this study, a bipolar nanosecond pulse with 20ns rising time is employed to generate air gas-liquid diffuse discharge plasma with room gas temperature in quartz tube at atmospheric pressure. The image of the discharge and optical emission spectra of active species in the plasma are recorded. The plasma gas temperature is determined to be approximately 390K by compared the experimental spectra with the simulated spectra, which is slightly higher than the room temperature. The result indicated that the gas temperature rises gradually with pulse peak voltage increasing, while decreases slightly with the electrode gap distance increasing. As an important application, bipolar nanosecond pulse discharge is used to sterilize the common microorganisms (Actinomycetes, Candida albicans and Escherichia coli) existing in drinking water, which performs high sterilization efficiency. PMID:24845733

Wang, Sen; Wang, Wen-chun; Yang, De-zheng; Liu, Zhi-jie; Zhang, Shuai

2014-10-15

156

Optical and application study of gas-liquid discharge excited by bipolar nanosecond pulse in atmospheric air  

NASA Astrophysics Data System (ADS)

In this study, a bipolar nanosecond pulse with 20 ns rising time is employed to generate air gas-liquid diffuse discharge plasma with room gas temperature in quartz tube at atmospheric pressure. The image of the discharge and optical emission spectra of active species in the plasma are recorded. The plasma gas temperature is determined to be approximately 390 K by compared the experimental spectra with the simulated spectra, which is slightly higher than the room temperature. The result indicated that the gas temperature rises gradually with pulse peak voltage increasing, while decreases slightly with the electrode gap distance increasing. As an important application, bipolar nanosecond pulse discharge is used to sterilize the common microorganisms (Actinomycetes, Candida albicans and Escherichia coli) existing in drinking water, which performs high sterilization efficiency.

Wang, Sen; Wang, Wen-chun; Yang, De-zheng; Liu, Zhi-jie; Zhang, Shuai

2014-10-01

157

Evaluation of the Alignment of Liquid Crystal Molecules on SiO2 Alignment Layer by Attenuated Total Reflection Method Utilizing Surface Plasmon and Guided Wave Excitation Modes  

NASA Astrophysics Data System (ADS)

In this study, we report on the evaluation of tilt angles of liquid crystal (LC) molecules near the surface of SiO2 alignment layers and in the whole cell when constant voltages are applied. A LC molecule, 4-cyano-4'n-pentylbiphenyl, was used in this study. The LC cell consisted of Au (50nm) / SiO2 (30nm) /LC (3 ?m)/ SiO2 (30nm) / Au (100nm) system. SiO2 alignment layers were obliquely evaporated on both Au surfaces. Surface plasmon resonance and guided waveguide excitation modes in attenuated total reflection configuration were used to monitor the alignment property of LC molecules adjacent to the surface and the bulk in the LC cell. In the ATR angular scan properties, the theoretical fittings agreed well with the experimental data on the assumption of simplified 5 LC layers model. The profile of the tilt angles from the surface to inside the cells was obtained by the theoretical fitting. In comparison with the internal bulk region, LC molecules near the surface required higher voltages to change their tilt angles toward vertical direction. As demonstrated in this report, this technique should provide the useful information to understand the interfacial phenomena for LC displays.

Ikarashi, Aya; Baba, Akira; Shinbo, Kazunari; Kato, Keizo; Kaneko, Futao

158

Towards an easy-to-use tuberculosis diagnosis through exhaled breath analysis: a liquid fluorimeter with an excitation at 265 nm  

NASA Astrophysics Data System (ADS)

The struggle against tuberculosis is one of the World Health Organization priorities. Identifying in a short time, patients with active tuberculosis, would bring a tremendous improvement to the current situation. Recovering from this infectious and deadly disease (2 million of death per year) is possible with a correct diagnosis to give an appropriate treatment. Unfortunately, most common tuberculosis diagnoses have few drawbacks: - skin tests: not reliable at 100% and need an incubation of 2 days before the diagnosis, - blood tests: costly and sophisticated technology, - chest X-ray: the first step before the sputum tests used for a bacterial culture with a final diagnosis given within 2 weeks. A tuberculosis test based on exhaled breath analysis is a prospective and noninvasive solution, cheap and easy to use and to transport. This test lies on a fluoregenic detection of niacin, a well-known mycobacterium tuberculosis specific metabolite. In this paper, it is assumed that the selected probe is specific to niacin and that exhaled breath does not contain any interfering species. To address this problem, a fluorimeter is developed with a cheap and cooled CCD (? 2k$) as a sensor, to easily determine the suitable "fluorescent zone". In comparing aqueous solutions with and without niacin, 250 pM of niacin have been detected. With a commercial fluorimeter (Fluorolog from Horiba), only 200 nM of niacin are detected. The present detection remains 10 times above the estimated targeted value for a tuberculosis test. The excitation source is a LED, which typically emits 20 ?W at 265 nm through an optical fiber. The emission signal is detected around 545 nm. A typical light exposure lasts 700 seconds. Analysis of biomarkers with a liquid fluorimeter is generic and promising as health diagnosis.

Hue, J.; Dupoy, M.; Vignoud, S.; Ricaud, J. L.; Tran-Thi, T.; Karpe, S.; Novelli-Rousseau, A.; Mallard, F.

2013-03-01

159

PHYSICAL REVIEW B VOLUME 41, NUMBER 7 1 MARCH 1990 Temperature dependence of the phonon and roton excitations in liquid He  

E-print Network

, University ofKeele, Keele ST5 5BG, United Kingdom and Science and Engineering Research Counci I, Daresbury in the "phonon" and "roton" regions, respectively, of the single excitation dispersion curve of the superfluid

Glyde, Henry R.

160

Exciter switch  

NASA Technical Reports Server (NTRS)

A new exciter switch assembly has been installed at the three DSN 64-m deep space stations. This assembly provides for switching Block III and Block IV exciters to either the high-power or 20-kW transmitters in either dual-carrier or single-carrier mode. In the dual-carrier mode, it provides for balancing the two drive signals from a single control panel located in the transmitter local control and remote control consoles. In addition to the improved switching capabilities, extensive monitoring of both the exciter switch assembly and Transmitter Subsystem is provided by the exciter switch monitor and display assemblies.

Mcpeak, W. L.

1975-01-01

161

Excite Travel  

NSDL National Science Digital Library

Excite Travel is one of the most comprehensive international guides to communities around the world. Excite Travel provides easy and timely access to information on travel, entertainment, and local business, plus government and community services for all regions of the world.

1998-01-01

162

Exciting Pools  

ERIC Educational Resources Information Center

Advocates the creation of swimming pool oscillations as part of a general investigation of mechanical oscillations. Presents the equations, procedure for deriving the slosh modes, and methods of period estimation for exciting swimming pool oscillations. (GS)

Wright, Bradford L.

1975-01-01

163

Variational theory of correlated Fermi-liquid state in the Kondo lattice model  

SciTech Connect

This paper reports on a variational wave function constructed and studied for the spin-compensated Fermi-liquid-type ground state in the Kondo lattice model. The spins of the localized f-electrons are compensated by overlapping conduction-electron clouds. In accordance with Luttinger's theorem, the volume enclosed by the Fermi surface corresponds to the total number of electrons, i.e., it includes the f-electrons as well as the conduction electrons. An approximate analytic treatment of the correlated heavy Fermi liquid is given by using the Gutzwiller approximation.

Fazekas, P. (Inst. fur Theoretische Physik, Universitat zu Koln, Zulpicher Str. 77, D-5000 Koln 41 (DE)); Shiba, H. (Tokyo Inst. of Tech. (Japan). Dept. of Physics)

1991-01-01

164

Effect of time profile of laser pulse on the excitation of sound signals in a liquid with a series of laser pulses  

Microsoft Academic Search

We have studied the sound generation with high repetition rate pulsed laser. We have solved the inhomogeneous wave equation for acoustic pressure in a liquid generated by a laser, using Green’s function formalism and convolution technique. To obtain the maximum pressure of the sound waves, we found the conditions on repetition rate and on period of laser pulse of various

V. K. Sayal; L. L. Yadav; K. P. Maheshwari

2011-01-01

165

Effect of time profile of laser pulse on the excitation of sound signals in a liquid with a series of laser pulses  

Microsoft Academic Search

We have studied the sound generation with high repetition rate pulsed laser. We have solved the inhomogeneous wave equation for acoustic pressure in a liquid generated by a laser, using Green's function formalism and convolution technique. To obtain the maximum pressure of the sound waves, we found the conditions on repetition rate and on period of laser pulse of various

V. K. Sayal; L. L. Yadav; K. P. Maheshwari

2011-01-01

166

Excited Insects  

E-print Network

but not killing them doesn't actually count as true celebration. Now, China. There's a country that knows how to make a bug feel good. Bugs have their very own holiday in the Chinese calendar. It's called the Feast of the Excited Insects and it falls on March 5th...

Hacker, Randi

2011-04-06

167

Magnetostrictive resonance excitation  

DOEpatents

The resonance frequency spectrum of a magnetostrictive sample is remotely determined by exciting the magnetostrictive property with an oscillating magnetic field. The permeability of a magnetostrictive material and concomitant coupling with a detection coil varies with the strain in the material whereby resonance responses of the sample can be readily detected. A suitable sample may be a magnetostrictive material or some other material having at least one side coated with a magnetostrictive material. When the sample is a suitable shape, i.e., a cube, rectangular parallelepiped, solid sphere or spherical shell, the elastic moduli or the material can be analytically determined from the measured resonance frequency spectrum. No mechanical transducers are required and the sample excitation is obtained without contact with the sample, leading to highly reproducible results and a measurement capability over a wide temperature range, e.g. from liquid nitrogen temperature to the Curie temperature of the magnetostrictive material.

Schwarz, Ricardo B. (Los Alamos, NM); Kuokkala, Veli-Tapani (Tampere, FI)

1992-01-01

168

Effect of time profile of laser pulse on the excitation of sound signals in a liquid with a series of laser pulses  

NASA Astrophysics Data System (ADS)

We have studied the sound generation with high repetition rate pulsed laser. We have solved the inhomogeneous wave equation for acoustic pressure in a liquid generated by a laser, using Green's function formalism and convolution technique. To obtain the maximum pressure of the sound waves, we found the conditions on repetition rate and on period of laser pulse of various shapes. Our analysis shows that the sound generated in a liquid with a series of laser pulses is highly affected by the time profile of the pulses besides other parameters, namely laser beam diameter, laser beam optical wavelength, repetition rate and period of laser pulse. This effect is pronounced particularly in frequency domain. We found that the noise of higher harmonics in the generated sound can be greatly removed with the proper choice of the time profile of the laser pulses. It is found that the pressure is generated around the fundamental frequency for the half-sine and rectangular pulses, with the proper choice of repetition rate and period of pulse. The application of the present analysis for underwater communication is pointed out.

Sayal, V. K.; Yadav, L. L.; Maheshwari, K. P.

2011-04-01

169

Excited Delirium  

PubMed Central

Excited (or agitated) delirium is characterized by agitation, aggression, acute distress and sudden death, often in the pre-hospital care setting. It is typically associated with the use of drugs that alter dopamine processing, hyperthermia, and, most notably, sometimes with death of the affected person in the custody of law enforcement. Subjects typically die from cardiopulmonary arrest, although the cause is debated. Unfortunately an adequate treatment plan has yet to be established, in part due to the fact that most patients die before hospital arrival. While there is still much to be discovered about the pathophysiology and treatment, it is hoped that this extensive review will provide both police and medical personnel with the information necessary to recognize and respond appropriately to excited delirium. PMID:21691475

Takeuchi, Asia; Ahern, Terence L.; Henderson, Sean O.

2011-01-01

170

Excited baryons  

SciTech Connect

The status of the theory of the low-energy approach to hadron structure is reviewed briefly by surveying a few relevant models. A few examples of tests needed to sort out the predictions of different models pertaining to the quark-gluon structure of hadrons are discussed, and given the resulting physics objectives, a few experimental options for excited baryon research at CFBAF are suggested. (LEW)

Mukhopadhyay, N.C.

1986-01-01

171

Excited Delirium  

Microsoft Academic Search

“Excited delirium accounts for 1% of our EDP (emotionally disturbed persons) cases and 99% of our headaches.” This comment,\\u000a made some years ago at a New York City conference of police chiefs captures the managerial and legal concerns of this entity.\\u000a Police managers are concerned because their officers are suddenly confronted with psychotic, violent persons, which sets into\\u000a motion an

Charles V. Wetli

172

Transmitting Electromagnetic Energy into Liquids  

NASA Technical Reports Server (NTRS)

Rough liquid surface enhances coupling. Agitating surface of liquid nitrogen bath with periodic or aperiodic excitation enhances electromagnetic coupling between microwave horn and blackbody temperature standard immersed in liquid. Useful in interfaces between electromagnetic radiation and liquids. Biomedical, radar, and meteorological applications.

Johnston, E. J.

1984-01-01

173

PREFACE: Functionalized Liquid Liquid Interfaces  

NASA Astrophysics Data System (ADS)

Most natural processes take place at interfaces. For this reason, surface science has been a focal point of modern research. At solid-liquid interfaces one can induce various species to adsorb or react, and thus may study interactions between the substrate and adsorbates, kinetic processes, optical properties, etc. Liquid-liquid interfaces, formed by immiscible liquids such as water and oil, have a number of distinctive features. Both sides of the interface are amenable to detailed physical and chemical analysis. By chemical or electrochemical means, metal or semiconductor nanoparticles can be formed or localised at the interface. Surfactants can be used to tailor surface properties, and also to place organic molecular or supermolecular constructions at the boundary between the liquids. Electric fields can be used to drive ions from one fluid to another, or even change the shape of the interface itself. In many cases, both liquids are optically transparent, making functionalized liquid-liquid interfaces promising for various optical applications based on the transmission or reflection of light. An advantage common to most of these systems is self-assembly; because a liquid-liquid interface is not mechanically constrained like a solid-liquid interface, it can easily access its most stable state, even after it has been driven far from equilibrium. This special issue focuses on four modes of liquid-liquid interfacial functionalization: the controlled adsorption of molecules or nanoparticles, the formation of adlayers or films, electrowetting, and ion transfer or interface-localized reactions. Interfacial adsorption can be driven electrically, chemically, or mechanically. The liquid-liquid interface can be used to study how anisotropic particles orient at a surface under the influence of a field, how surfactants interact with other adsorbates, and how nanoparticles aggregate; the transparency of the interface also makes the chirality of organic adsorbates amenable to optical study. Film formation goes a step beyond adsorption; some surfactants form monolayers or multilayers at the interface. A polymer microfilm or a polymer-particle matrix can be synthesized at the liquid-liquid boundary. Such films exhibit unique adsorption and ion-intercalation properties of their own. Electrowetting refers broadly to the phenomenon in which an applied voltage modulates the shape of a liquid-liquid interface, essentially by altering the surface tension. Electric fields can be used to induce droplets on solid substrates to change shape, or to affect the structure of liquid-liquid emulsions. Various chemical reactions can be performed at the liquid-liquid boundary. Liquid-liquid microelectrodes allow detailed study of ion-transfer kinetics at the interface. Photochemical processes can also be used to control the conformations of molecules adsorbed at the interface. But how much precise control do we actually have on the state of the interfacial region? Several contributions to this issue address a system which has been studied for decades in electrochemistry, but remains essentially unfamilar to physicists. This is the interface between two immiscible electrolytic solutions (ITIES), a progressing interdisciplinary field in which condensed-matter physics and physical chemistry meet molecular electrochemistry. Why is it so exciting? The reason is simple. The ITIES is chargeable: when positioned between two electrodes it can be polarized, and back- to-back electrical double layers form on both sides of the liquid-liquid interface. Importantly, the term immiscible refers not only to oil and water but also to the electrolytes. Inorganic electrolytes, such as alkali halides, tend to stay in water, whereas organic electrolytes, such as tetrabutylammonium tetraphenylborate, stay in oil. This behaviour arises because energies of the order of 0.2-0.3 eV are needed to drive ions across the interface. As long as these free energies of transfer are not exceeded by the external potential bias, the ITIES works as an 'electrode'; there is no traffic of ions

Girault, Hubert; Kornyshev, Alexei A.; Monroe, Charles W.; Urbakh, Michael

2007-09-01

174

Fission of excited nuclei with Z{sup 2}/A = 20 - 33: Mass-energy distributions of fragments, angular momentum, and liquid-drop model  

SciTech Connect

The mass-energy distributions of fission fragments in the reactions {sup 20}Ne + {sup 99}Ru, {sup 106,110}Cd, {sup 112,118,134}Sn are measured by means of a two-arm time-of-flight spectrometer DEMAS. The fission of {sup 124}Ba in two ion-target combinations {sup 12}C + {sup 112}Sn and {sup 25}Mg + {sup 99}Ru is also studied. Global analysis of data obtained in (C) this study and data reported by other authors made it possible to determine the variances {sigma}{sub M}{sup 2} and {sigma}{sub E}{sup 2} of mass E and energy distributions as functions of the angular momentum l of the compound nucleus and nucleon composition. It is found that, for nuclei with Z{sup 2}/A {le}30 (in contrast to heavier nuclei), an increase in the angular momentum introduced into a nucleus undergoing fission leads to the narrowing of the mass distributions of fragments. The stability of nuclei to mass-asymmetric deformation is studied, and it is shown that the Sierk liquid-drop model with finite-range nuclear forces provides the closest description of experimental data in the region on Z{sup 2}/A {approximately} 20 - 30. The Businaro-Gallone point at which the nucleus is absolutely unstable to mass-asymmetric deformations is found to be (Z{sup 2}/A){sub BG} = 22.0 {+-} 0.6. 97 refs., 16 figs., 5 tabs.

Itkis, M.G.; Muzychka, Yu.A.; Oganessian, Yu.Ts. [Joint Institute for Nuclear Research, Moscow (Russian Federation)] [and others

1995-12-01

175

Self-trapped excitations in condensed matter physics  

Microsoft Academic Search

The authors discuss a general formulation for self-trapped excitations in condensed matter physics. Previously known aspects include lattice polarons, spin polarons, bubblons, etc. New aspects involve collective excitation self-trapping; solidons in liquid He have been suggested as the correct description for rotons. They emphasise the difference of self-trapped excitations with order parameter fluctuations.

M. Heritier; P. Lederer; G. Montambaux

1980-01-01

176

Hydrodynamic pressure in liquid filled container  

NASA Astrophysics Data System (ADS)

Liquid storage tanks are used to store oil, drinking water and different liquids which are necessary in industry and energy production. Partially liquid filled container shows free surface movement under external excitation this phenomenon is known as sloshing of liquid. When external excitation frequency matches the natural frequency of sloshing, a violent oscillation may occur that causes excess dynamic pressure on the tank structure. The dynamic behavior of liquid storage tanks under seismic excitation has been the subject of numerous theoretical and experimental investigations. This paper presents a pressure based finite element analysis of the liquid-structure systems considering the coupled effect of elastic structure and liquid. The equation of motion of the liquid is considered as incompressible and inviscid. The hydrodynamic pressure variation along a wall of prismatic container is studied and presented for different fill depth of liquid under sinusoidal base excitation.

Maiti, Pabitra Ranjan

2011-12-01

177

Excitations in a Bose-condensed Liquid  

Microsoft Academic Search

This volume gives an up-to-date, systematic account of the microscopic theory of Bose-condensed fluids developed since the late 1950s. The core of the present book is the development of the field-theoretic analysis needed to deal with a Bose-condensed fluid. However, the author also brings out the essential physics behind the formal Green's function techniques and presents plausible scenarios to understand

Allan Griffin

1993-01-01

178

Laser diffraction effect from liquid surface wave  

Microsoft Academic Search

Based on the laser technique,a method of detecting liquid surface wave was proposed.In this experiment, the intensity of liquid surface wave was controlled by the electromagnetic exciter and the frequecy of the exciter was controlled by the signal generator;When a He-Ne laser beam was obliquely incident upon the liquid surface wave directly, laser diffraction patterns from liquid surface waves can

Daobin Luo; Jianke Liu

2010-01-01

179

Field-Induced Tomonaga-Luttinger Liquid Phase of a Two-Leg Spin-1/2 Ladder with Strong Leg Interactions  

E-print Network

. Inelastic neutron scattering and the specific heat measurements in both phases are in good agreement with theoretical calculations, demonstrating that DIMPY is the first model material for an S ¼ 1=2 two-leg spin

Weston, Ken

180

Non-existence of the Luttinger-Ward functional and misleading convergence of skeleton diagrammatic series for Hubbard-like models  

E-print Network

The Luttinger-Ward functional $\\Phi[\\mathbf{G}]$, which expresses the thermodynamic grand potential in terms of the interacting single-particle Green's function $\\mathbf{G}$, is found to be ill-defined for fermionic models with the Hubbard on-site interaction. In particular, we show that the self-energy $\\mathbf{\\Sigma}[\\mathbf{G}] \\propto \\delta\\Phi[\\mathbf{G}]/\\delta \\mathbf{G}$ is \\textit{not} a single-valued functional of $\\mathbf{G}$: in addition to the physical solution for $\\mathbf{\\Sigma}[\\mathbf{G}]$, there exists at least one qualitatively distinct unphysical branch. This result is demonstrated for several models: the Hubbard atom, the Anderson impurity model, and the full two-dimensional Hubbard model. Despite this pathology, the skeleton Feynman diagrammatic series for $\\mathbf{\\Sigma}$ in terms of $\\mathbf{G}$ is found to converge at least for moderately low temperatures. However, at strong interactions, its convergence is to the unphysical branch. This reveals a new scenario of breaking down of diagrammatic expansions. In contrast, the bare series in terms of the non-interacting Green's function $\\mathbf{G}_0$ converges to the correct physical branch of $\\mathbf{\\Sigma}$ in all cases currently accessible by diagrammatic Monte Carlo. Besides their conceptual importance, these observations have important implications for techniques based on the explicit summation of diagrammatic series.

Evgeny Kozik; Michel Ferrero; Antoine Georges

2014-07-21

181

Faraday waves under time-reversed excitation.  

PubMed

Do parametrically driven systems distinguish periodic excitations that are time mirrors of each other? Faraday waves in a Newtonian fluid are studied under excitation with superimposed harmonic wave forms. We demonstrate that the threshold parameters for the stability of the ground state are insensitive to a time inversion of the driving function. This is a peculiarity of some dynamic systems. The Faraday system shares this property with standard electroconvection in nematic liquid crystals [J. Heuer et al., Phys. Rev. E 78, 036218 (2008)]. In general, time inversion of the excitation affects the asymptotic stability of a parametrically driven system, even when it is described by linear ordinary differential equations. Obviously, the observed symmetry has to be attributed to the particular structure of the underlying differential equation system. The pattern selection of the Faraday waves above threshold, on the other hand, discriminates between time-mirrored excitation functions. PMID:23496716

Pietschmann, Dirk; Stannarius, Ralf; Wagner, Christian; John, Thomas

2013-03-01

182

Non-Fermi-liquid and topological states with strong spin-orbit coupling.  

PubMed

We argue that a class of strongly spin-orbit-coupled materials, including some pyrochlore iridates and the inverted band gap semiconductor HgTe, may be described by a minimal model consisting of the Luttinger Hamiltonian supplemented by Coulomb interactions, a problem studied by Abrikosov and collaborators. It contains twofold degenerate conduction and valence bands touching quadratically at the zone center. Using modern renormalization group methods, we update and extend Abrikosov's classic work and show that interactions induce a quantum critical non-Fermi-liquid phase, stable provided time-reversal and cubic symmetries are maintained. We determine the universal power-law exponents describing various observables in this Luttinger-Abrikosov-Beneslavskii state, which include conductivity, specific heat, nonlinear susceptibility, and the magnetic Gruneisen number. Furthermore, we determine the phase diagram in the presence of cubic and/or time-reversal symmetry breaking perturbations, which includes a topological insulator and Weyl semimetal phases. Many of these phases possess an extraordinarily large anomalous Hall effect, with the Hall conductivity scaling sublinearly with magnetization ?(xy)?M0.51. PMID:24289698

Moon, Eun-Gook; Xu, Cenke; Kim, Yong Baek; Balents, Leon

2013-11-15

183

Liquid-Liquid Extraction Processes  

E-print Network

Liquid-liquid extraction is the separation of one or more components of a liquid solution by contact with a second immiscible liquid called the solvent. If the components in the original liquid solution distribute themselves differently between...

Fair, J. R.; Humphrey, J. L.

1983-01-01

184

Wide band spectroscopy of liquid surface ripplon  

Microsoft Academic Search

A light scattering technique was developed to measure the propagation of liquid surface waves over a wide frequency range. Thermal fluctuation of liquid surface displacement excites a surface tension wave, called the ripplon, whose behavior gives information on dynamic properties of the liquid surface. A laser beam is scattered by the ripplon, and the power spectrum of the scattered light

K. Sakai; H. Tanaka; K. Takagi

1990-01-01

185

The electron-hole liquid in semiconductors  

Microsoft Academic Search

In highly excited semiconductors at low enough temperatures nonequilibrium electrons, holes and excitons condense into droplets of a metallic degenerate Fermi liquid, the so called electron-hole liquid. General properties of this new quantum liquid are reviewed including possible types of its phase diagram; the strong dependence of the phase diagram on the band and crystalline structure of the semiconductor, magnetic

L. V. Keldysh

1986-01-01

186

Excitations of superfluid 4 He in porous media: Aerogel and Vycor  

E-print Network

Excitations of superfluid 4 He in porous media: Aerogel and Vycor O. Plantevin and B. Fa structure factor S(Q, ) and the elementary excitations of liquid 4 He immersed in aerogel and Vycor. In both and superfluid density, S(T), of liquid 4 He in aerogel and Vycor have been made over the past 30 years.1

Glyde, Henry R.

187

Medium-frequency impulsive-thrust-excited slosh waves during propellant reorientation with a geyser  

Microsoft Academic Search

Slosh wave excitation induced by a resettling flowfield activated by 1.0-Hz impulsive thrust during the course of liquid reorientation with the initiation of geyser for liquid-fill levels of 30, 50, 65, 70, and 80 percent has been studied. Characteristics of slosh waves of various frequencies excited by the resettling flowfield are discussed. Slosh wave excitations shift the fluid mass distribution

R. J. Hung; K. L. Shyu; C. C. Lee

1992-01-01

188

Conductivity of a generic helical liquid  

NASA Astrophysics Data System (ADS)

A quantum spin Hall insulator is a two-dimensional state of matter consisting of an insulating bulk and one-dimensional helical edge states. While these edge states are topologically protected against elastic backscattering in the presence of disorder, interaction-induced inelastic terms may yield a finite conductivity. By using a kinetic equation approach, we find the backscattering rate ?-1 and the semiclassical conductivity in the regimes of high (? ??-1) and low (? ??-1) frequency. By comparing the two limits, we find that the parametric dependence of conductivity is described by the Drude formula for the case of a disordered edge. On the other hand, in the clean case where the resistance originates from umklapp interactions, the conductivity takes a non-Drude form with a parametric suppression of scattering in the dc limit as compared to the ac case. This behavior is due to the peculiarity of umklapp scattering processes involving necessarily the state at the "Dirac point." In order to take into account Luttinger liquid effects, we complement the kinetic equation analysis by treating interactions exactly in bosonization and calculating conductivity using the Kubo formula. In this way, we obtain the frequency and temperature dependence of conductivity over a wide range of parameters. We find the temperature and frequency dependence of the transport scattering time in a disordered system as ? ˜[max(?,T)]-2K-2, for K >2/3 and ? ˜[max(?,T)]-8K+2 for K <2/3.

Kainaris, Nikolaos; Gornyi, Igor V.; Carr, Sam T.; Mirlin, Alexander D.

2014-08-01

189

8. POWERHOUSE INTERIOR SHOWING EXCITER No. 1 IN FOREGROUND, EXCITER ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. POWERHOUSE INTERIOR SHOWING EXCITER No. 1 IN FOREGROUND, EXCITER No. 2., AND GENERATOR UNITS BEHIND EXCITER No. 2 IN BACKGROUND. EXCITER No. 1 GENERATOR HAS A COVER OVER TOP HALF OF COMMUTATOR ELEMENT. VIEW TO NORTHWEST. - Rush Creek Hydroelectric System, Powerhouse Exciters, Rush Creek, June Lake, Mono County, CA

190

Quasiparticles and Fermi liquid behaviour in an organic metal  

PubMed Central

Many organic metals display exotic properties such as superconductivity, spin-charge separation and so on and have been described as quasi-one-dimensional Luttinger liquids. However, a genuine Fermi liquid behaviour with quasiparticles and Fermi surfaces have not been reported to date for any organic metal. Here, we report the experimental Fermi surface and band structure of an organic metal (BEDT-TTF)3Br(pBIB) obtained using angle-resolved photoelectron spectroscopy, and show its consistency with first-principles band structure calculations. Our results reveal a quasiparticle renormalization at low energy scales (effective mass m*=1.9?me) and ?2 dependence of the imaginary part of the self energy, limited by a kink at ~50?meV arising from coupling to molecular vibrations. The study unambiguously proves that (BEDT-TTF)3Br(pBIB) is a quasi-2D organic Fermi liquid with a Fermi surface consistent with Shubnikov-de Haas results. PMID:23011143

Kiss, T.; Chainani, A.; Yamamoto, H.M.; Miyazaki, T.; Akimoto, T.; Shimojima, T.; Ishizaka, K.; Watanabe, S.; Chen, C.-T.; Fukaya, A.; Kato, R.; Shin, S.

2012-01-01

191

Laser diffraction effect from liquid surface wave  

NASA Astrophysics Data System (ADS)

Based on the laser technique,a method of detecting liquid surface wave was proposed.In this experiment, the intensity of liquid surface wave was controlled by the electromagnetic exciter and the frequecy of the exciter was controlled by the signal generator;When a He-Ne laser beam was obliquely incident upon the liquid surface wave directly, laser diffraction patterns from liquid surface waves can be collected by charge-coupled device at the same time. The experiment phenomena were visible and accordant to the theory well. The experiment results indicate that the proposed method has the advantages of high sensitivity, high speed and non-destructive.

Luo, Daobin; Liu, Jianke

2010-08-01

192

Excitations of the torelon  

Microsoft Academic Search

The excitations of gluonic flux tube in a periodic lattice are examined. Monte Carlo simulations from an anisotropic lattice are presented and the comparison with effective string models is discussed.

K. J. Juge; J. Kuti; F. Maresca; C. Morningstar; M. Peardon

2004-01-01

193

Experiments on excitation waves  

Microsoft Academic Search

Recent trends in the experimentation on chemical and biochemical excitation waves are presented. In the Belousov-Zhabotinsky\\u000a reaction, which is the most suitable chemical laboratory system for the study of wave propagation in excitable medium, the\\u000a efficient control of wave dynamics by electrical fields and by light illumination is illustrated. In particular, the effects\\u000a of a feedback control are shown. Further

S. C. MOiler

194

A Novel Liquid-Liquid Transition in Undercooled Ti-Zr-Ni Liquids  

NASA Technical Reports Server (NTRS)

If crystallization can be avoided, liquids enter a metastable (undercooled) state below their equilibrium liquidus temperatures, T(sub l), finally 'freezing' into a glass below a characteristic temperature called the glass transition temperature, T(sub g). In rare cases, the undercooled liquid may undergo a liquid-liquid phase transition (liquid polymorphism) before entering the glassy state. This has been suggested from experimental studies of H2O and Si. Such phase transitions have been predicted in some stable liquids, ie. above T(sub l) at atmospheric pressure, for SiO2 and BeF2, but these have not been verified experimentally. They have been observed in liquids of P, Si and C, but only under high pressure. In this letter we present the first experimental evidence for a phase transition in a low viscosity metallic liquid that is driven by an approach to a constant entropy configuration state and correlated with a growing icosahedral order in the liquid. A maximum in the specific heat at constant pressure, similar to what is normally observed near T(sub g), is reported for undercooled liquids of quasicrystal-forming Ti-Zr-Ni alloys. A two-state excitation model that includes cooperativity by incorporating a temperature-dependent excitation energy, fits the specific heat data well, signaling a phase transition. An inflection in the liquid density with decreasing temperature instead of a discontinuity indicates that this is not a typical first order phase transition; it could be a weakly first order or higher order transition. While showing many similarities to a glass transition, this liquid-liquid phase transition occurs in a mobile liquid, making it novel.

Lee, G. W.; Gangopadhyay, A. K.; Kelton, K. F.; Bradshaw, R. C.; Hyers, R. W.; Rathz, T. J.; Rogers, J. R.

2004-01-01

195

Sloshing motions in excited tanks  

NASA Astrophysics Data System (ADS)

A fully non-linear finite difference model has been developed based on inviscid flow equations. Numerical experiments of sloshing wave motion are undertaken in a 2-D tank which is moved both horizontally and vertically. Results of liquid sloshing induced by harmonic base excitations are presented for small to steep non-breaking waves. The simulations are limited to a single water depth above the critical depth corresponding to a tank aspect ratio of hs/ b=0.5. The numerical model is valid for any water depth except for small depth when viscous effects would become important. Solutions are limited to steep non-overturning waves. Good agreement for small horizontal forcing amplitude is achieved between the numerical model and second order small perturbation theory. For large horizontal forcing, non-linear effects are captured by the third-order single modal solution and the fully non-linear numerical model. The agreement is in general good, both amplitude and phase. As expected, the third-order compared to the second-order solution is more accurate. This is especially true for resonance, high forcing frequency and mode interaction cases. However, it was found that multimodal approximate forms should be used for the cases in which detuning effects occur due to mode interaction. We present some test cases where detuning effects are evident both for single dominant modes and mode interaction cases. Furthermore, for very steep waves, just before the waves overturn, and for large forcing frequency, a discrepancy in amplitude and phase occurs between the approximate forms and the numerical model. The effects of the simultaneous vertical and horizontal excitations in comparison with the pure horizontal motion and pure vertical motion is examined. It is shown that vertical excitation causes the instability associated with parametric resonance of the combined motion for a certain set of frequencies and amplitudes of the vertical motion while the horizontal motion is related to classical resonance. It is also found that, in addition to the resonant frequency of the pure horizontal excitation, an infinite number of additional resonance frequencies exist due to the combined motion of the tank. The dependence of the non-linear behaviour of the solution on the wave steepness is discussed. It is found that for the present problem, non-linear effects become important when the steepness reaches about 0.1, in agreement with the physical experiments of Abramson [Rep. SP 106, NASA, 1966].

Frandsen, Jannette B.

2004-05-01

196

Hydromagnet: A Self-Generating Liquid Conductor Electromagnet  

Microsoft Academic Search

A novel liquid electromagnet is investigated in which the exciting current is generated within the solenoid by forcing the liquid conductor radially inward through the space between two coaxial cylinders placed in an axial magnetic field. The tangential current thus generated within the flowing conductor adds to the initial applied field so that the device behaves like a self-excited, short-circuited

Henry H. Kolm; Osman K. Mawardi

1961-01-01

197

Highly excited atoms  

NASA Astrophysics Data System (ADS)

The physics of atoms in which an electron is excited to an exceptionally high energy level, termed Rydberg atoms, is discussed. Similarities between the essential properties of Rydberg atoms and the Bohr conception of the hydrogen atom are pointed out, and classical and quantum mechanical descriptions of atoms in a low-lying state and in a highly excited state are compared. Early observations of Rydberg atoms in the laboratory and in interstellar space are considered, and laboratory methods for the creation of Rydberg atoms are examined, with particular attention given to the excitation of alkali metal atoms to a particular Rydberg state by a tunable laser. Laser spectroscopic studies of the Stark effect in Rydberg atoms, Rydberg atom lifetimes with respect to electron tunneling and the effects of strong magnetic fields on the energy level structures of Rydberg atoms, which have revealed an unidentified apparent underlying symmetry in energy level structures, are presented.

Kleppner, D.; Littman, M. G.; Zimmerman, M. L.

1981-05-01

198

Excitation Methods for Bridge Structures  

SciTech Connect

This paper summarizes the various methods that have been used to excited bridge structures during dynamic testing. The excitation methods fall into the general categories of ambient excitation methods and measured-input excitation methods. During ambient excitation the input to the bridge is not directly measured. In contrast, as the category label implies, measured-input excitations are usually applied at a single location where the force input to the structure can be monitored. Issues associated with using these various types of measurements are discussed along with a general description of the various excitation methods.

Farrar, C.R.; Duffy, T.A.; Cornwell, P.J.; Doebling, S.W.

1999-02-08

199

Positron excitation of neon  

NASA Technical Reports Server (NTRS)

The differential and total cross section for the excitation of the 3s1P10 and 3p1P1 states of neon by positron impact were calculated using a distorted-wave approximation. The results agree well with experimental conclusions.

Parcell, L. A.; Mceachran, R. P.; Stauffer, A. D.

1990-01-01

200

Exploring Excited Hadrons  

E-print Network

Progress in extracting the spectrum of excited hadron resonances is reviewed and the key issues and challenges in such computations are outlined. The importance of multi-hadron states as simulations are done with lighter pion masses is discussed, and the need for all-to-all quark propagators is emphasized.

Colin Morningstar

2008-10-24

201

Exploring Excited Hadrons  

E-print Network

Progress in extracting the spectrum of excited hadron resonances is reviewed and the key issues and challenges in such computations are outlined. The importance of multi-hadron states as simulations are done with lighter pion masses is discussed, and the need for all-to-all quark propagators is emphasized.

Morningstar, C

2008-01-01

202

Quasiparticle excitations in Bose-Fermi mixtures  

SciTech Connect

We analyze the excitation spectrum of a three-dimensional Bose-Fermi mixture with tunable resonant interaction parameters and high hyperfine spin multiplets. We focus on a three-particle vertex describing fermionic and bosonic atoms which can scatter to create fermionic molecules or disassociate. For a single molecular level, in analogy to the single magnetic impurity problem we argue that the low-lying excitations of the mean-field theory are described by the Fermi-liquid picture with a quasiparticle weight and charge which is justified by a 1/N{sub {psi}}expansion, expected to be exact in the limit of infinite degeneracy (or very high fermionic spin) N{sub {psi}{yields}{infinity}}. Our emphasis is placed on the novel conditions for chemical equilibrium and how many-body chemical reactions renormalize the bosonic chemical potential, modifying condensation and superfluid-insulator transitions.

Akhanjee, Shimul [Condensed Matter Theory Laboratory, RIKEN, Wako, Saitama 351-0198 (Japan)

2010-08-15

203

PROPOSITION DE SUJET DE THESE Nom du laboratoire : Laboratoire de Physique des Solides  

E-print Network

). This was possible owing to the mapping of this problem to the Tomonaga-Luttinger Liquid (TLL) model, which describes-Channel Conductor in an Ohmic Environment: Mapping to a Tomonaga-Luttinger Liquid and Full Counting Statistics. Phys.3857, soumis à Nature Phys. (3) S. Jezouin and al, Tomonaga-Luttinger liquid physics in electronic quantum

Paris-Sud 11, Université de

204

Excitation of microseisms  

NASA Astrophysics Data System (ADS)

Excitation of microseisms is generally considered to be due to pressure change at ocean bottom, for which Longuet-Higgins derived his celebrated formula in 1950. Use of this formula is an approximation, however. Comparison with a more rigorous normal-mode formula shows that this conventional approach is acceptable for ocean depths less than 1 km but fails in deep oceans. On the other hand, there seems to be a multitude of evidence that source region for double-frequency microseim is near the coast and thus is generally in shallow water. An evidence from buoy data for nonlinearity in ocean waves is presented to support this view. If a source region is in shallow water, use of the Longuet-Higgins pressure formula at ocean bottom for the excitation of microseisms is justified, although one should pay attention to ocean depths very carefully.

Tanimoto, Toshiro

2007-03-01

205

Aperture excited dielectric antennas  

NASA Technical Reports Server (NTRS)

The results of a comprehensive experimental and theoretical study of the effect of placing dielectric objects over the aperture of waveguide antennas are presented. Experimental measurements of the radiation patterns, gain, impedance, near-field amplitude, and pattern and impedance coupling between pairs of antennas are given for various Plexiglas shapes, including the sphere and the cube, excited by rectangular, circular, and square waveguide feed apertures. The waveguide excitation of a dielectric sphere is modeled using the Huygens' source, and expressions for the resulting electric fields, directivity, and efficiency are derived. Calculations using this model show good overall agreement with experimental patterns and directivity measurements. The waveguide under an infinite dielectric slab is used as an impedance model. Calculations using this model agree qualitatively with the measured impedance data. It is concluded that dielectric loaded antennas such as the waveguide excited sphere, cube, or sphere-cylinder can produce directivities in excess of that obtained by a uniformly illuminated aperture of the same cross section, particularly for dielectric objects with dimensions of 2 wavelengths or less. It is also shown that for certain configurations coupling between two antennas of this type is less than that for the same antennas without dielectric loading.

Crosswell, W. F.; Chatterjee, J. S.; Mason, V. B.; Tai, C. T.

1974-01-01

206

Vibrational spraying of liquid by a thin rod  

NASA Astrophysics Data System (ADS)

The phenomenon of liquid spraying by a thin rod bent at a right angle and excited with a piezoelectric transducer at one end is observed when the rod touches the open liquid surface at the bending site. The spraying may be accompanied by the formation of a liquid jet, which is emitted from the free end of the bent rod.

Aleksandrov, V. A.

2008-02-01

207

Parametric Excitation of a DWSC  

E-print Network

to parametric excitation. This thesis examines the phenomenon of parametric excitation with respect to roll motion in head seas, using time-domain simulation and stability analysis. It examines the DWSC's susceptibility to parametric instability using the same...

Lakhotia, Chandan

2011-08-08

208

Apparatus for photon excited catalysis  

NASA Technical Reports Server (NTRS)

An apparatus is described for increasing the yield of photonically excited gas phase reactions by extracting excess energy from unstable, excited species by contacting the species with the surface of a finely divided solid.

Saffren, M. M. (inventor)

1977-01-01

209

Excitation of atmospheric pressure uniform dielectric barrier discharge using repetitive unipolar nanosecond-pulse generator  

Microsoft Academic Search

Dielectric barrier discharge (DBD) excitation by unipolar high voltage pulses is a promising approach for producing non-thermal plasma at atmospheric pressure. In this study, a magnetic compression solid-state pulsed power generator was used to produce repetitive nanosecond pulses for the excitation. The DBD is created using two liquid electrodes. The electrical characteristics of the discharge voltage and current are illustrated

Tao Shao; Yang Yu; Cheng Zhang; Dongdong Zhang; Zheng Niu; Jue Wang; Ping Yan; Yuanxiang Zhou

2010-01-01

210

Wigner crystallization of single photons in cold Rydberg ensembles.  

PubMed

The coupling of weak light fields to Rydberg states of atoms under conditions of electromagnetically induced transparency leads to the formation of Rydberg polaritons which are quasiparticles with tunable effective mass and nonlocal interactions. Confined to one spatial dimension their low energy physics is that of a moving-frame Luttinger liquid which, due to the nonlocal character of the repulsive interaction, can form a Wigner crystal of individual photons. We calculate the Luttinger K parameter using density-matrix renormalization group simulations and find that under typical slow-light conditions kinetic energy contributions are too strong for crystal formation. However, adiabatically increasing the polariton mass by turning a light pulse into stationary spin excitations allows us to generate true crystalline order over a finite length. The dynamics of this process and asymptotic correlations are analyzed in terms of a time-dependent Luttinger theory. PMID:24074081

Otterbach, Johannes; Moos, Matthias; Muth, Dominik; Fleischhauer, Michael

2013-09-13

211

Plasmonic excitations in nanostructures  

NASA Astrophysics Data System (ADS)

The prevalent classical model of plasmonic calculations for nano-scale metallic clusters is based on the Mie solution. Which consists of solving Maxwell's equations with the material being represented by a dielectric function on its spatial location. However, such a semi-empirical continuum description necessarily breaks down beyond a certain level of coarseness introduced by atomic length scales. Even the bulk based model used for the dielectric function fails by itself. This limitation of the Mie solution has been established by a quantum mechanical calculation with self-consistent treatment of the dielectric response. In order to understand better the plasmonic excitations at nearly atomic scale, we explored the collective electromagnetic response of atomic chains of various sizes and geometries, and we also computed plasmons in graphene in the presence of an impurity. For the atomic chains, we calculated the plasmonic resonances as a function of the system shape, direction of the external applied field, electron filling and atomic separation. Their frequency, oscillator strength and spatial modulation of the induced charge density were analyzed. It was shown that longitudinal and transverse modes can be controlled in amplitude and frequency by the cluster size. It was also observed an abrupt dependence of the modes on the electronic filling. We also find that changes in atomic spacings have a very different impact on low-energy vs. high-energy modes. And it was seen that changing the position of a single atom in a nanostructure can completely alter its collective dielectric response. This strong sensitivity to small changes is the key to controlling the dielectric properties of atomic scale structures, and it can thus become the gateway to a new generation of quantum devices which effectively utilize quantum physics for new functionalities. For graphene it was shown that impurities induce the formation of nanoscale localized plasmonic excitations in graphene sheets. It was studied the dependence of these excitations on the magnitude and size of the impurity potential and electronic filling. It was shown that the impurity potential and doping can be used to tune the properties of nano-plasmonic excitations, demonstrating that graphene is an inherently plasmonic material. It was found that the chemical potential can be used to turn them on and off, but it does not affect their frequency. While their frequency and amplitude can be tuned by varying the strength of the impurity potential. The method employed for this calculation had not been seen before. In principle the results discussed can be tested experimentally by high-frequency optical probes or STM. These results showed that collective excitations in finite systems have properties different from their bulk correspondents. Since there is not a macroscopic number of electrons in the system, the variation of one single electron causes observable differences. The localized resonant modes are very sensitive to even small variations in the system, for example the position of a single atom. This makes it difficult to establish general rules about the properties of collective excitations in atomic structures. On the other hand it also provides a vast range of possibilities that can be explored for achieving new functionalities.

Muniz, Rodrigo Angelo

212

A Liquid-Liquid Transition in an Undercooled Ti-Zr-Ni Liquid  

NASA Technical Reports Server (NTRS)

If crystallization can be avoided, liquids enter a metastable (undercooled) state below their equilibrium liquidus temperatures, TI, finally freezing into a glass below a characteristic temperature called the glass transition temperature, T,. In rare cases, the undercooled liquid may undergo a liquid-liquid phase transition (liquid polymorphism) before entering the glassy state. This has been suggested from experimental studies of HzO and Si4. Such phase transitions have been predicted in some stable liquids, i.e. above TI at atmospheric pressure, for Si02 and BeF;, but these have not been verified experimentally. They have been observed in liquids of P7, Sis and C9, but only under high pressure. All of these transitions are driven by an anomalous density change, i.e. change in local structure, with temperature or pressure. In this letter we present the first experimental evidence for a phase transition in a low viscosity liquid that is not driven by an anomalous density change, but by an approach to a constant configuration state. A maximum in the specific heat at constant pressure, similar to what is normally observed near T,, is reported here for undercooled low viscosity liquids of quasicrystal- forming Ti-Zr-Ni alloys. that includes cooperativity, by incorporating a temperature dependent excitation energy fits the data well, signaling a phase transition.

Lee, G. W.; Gangopadhyay, A. K.; Kelton, K. F.; Hyers, R. W.; Rathz, T. J.; Rogers, J. R.

2003-01-01

213

Highly excited atoms  

SciTech Connect

Highly excited atoms are often called Rydberg atoms. These atoms have a wealth of exotic properties which are discussed. Of special interest, are the effects of electric and magnetic fields on Rydberg atoms. Ordinary atoms are scarcely affected by an applied electric or magnetic field; Rydberg atoms can be strongly distorted and even pulled apart by a relatively weak electric field, and they can be squeezed into unexpected shapes by a magnetic field. Studies of the structure of Rydberg atoms in electric and magnetic fields have revealed dramatic atomic phenomena that had not been observed before. (SC)

Kleppner, D.; Littman, M.G.; Zimmerman, M.L.

1981-05-01

214

Do liquidity measures measure liquidity?  

Microsoft Academic Search

Given the key role of liquidity in finance research, identifying high quality proxies based on daily (as opposed to intraday) data would permit liquidity to be studied over relatively long timeframes and across many countries. Using new measures and widely employed measures in the literature, we run horseraces of annual and monthly estimates of each measure against liquidity benchmarks. Our

Ruslan Y. Goyenko; Craig W. Holden; Charles A. Trzcinka

2009-01-01

215

Sealing liquids with magnetic liquids  

Microsoft Academic Search

The stability and durability of magnetic liquid seals have been tested under the condition of sealing other liquids. The results show that the deterioration of the magnetic fluid depends on the nature and combination of magnetic and nonmagnetic liquids as well as on the shaft speed, the temperature of the seal and the gradient of the magnetic field. Seal life

J. Kurfess; H. K. Müller

1990-01-01

216

Fluorescent optical liquid level sensor  

DOEpatents

A liquid level sensor comprising a transparent waveguide containing fluorescent material that is excited by light of a first wavelength and emits at a second, longer wavelength. The upper end of the waveguide is connected to a light source at the first wavelength through a beveled portion of the waveguide such that the input light is totally internally reflected within the waveguide above an air/liquid interface in a tank but is transmitted into the liquid below this interface. Light is emitted from the fluorescent material only in those portions of the waveguide that are above the air/liquid interface, to be collected at the upper end of the waveguide by a detector that is sensitive only to the second wavelength. As the interface moves down in the tank, the signal strength from the detector will increase.

Weiss, Jonathan D. (Albuquerque, NM)

2001-01-01

217

Fusion excitation function revisited  

E-print Network

We report on a comprehensive systematics of fusion-evaporation and/or fusion-fission cross sections for a very large variety of systems over an energy range 4-155 A.MeV. Scaled by the reaction cross sections, fusion cross sections do not show a universal behavior valid for all systems although a high degree of correlation is present when data are ordered by the system mass asymmetry.For the rather light and close to mass-symmetric systems the main characteristics of the complete and incomplete fusion excitation functions can be precisely determined. Despite an evident lack of data above 15A.MeV for all heavy systems the available data suggests that geometrical effects could explain the persistence of incomplete fusion at incident energies as high as 155A.MeV.

Ph. Eudes; Z. Basrak; F. Sébille; V. de la Mota; G. Royer; M. Zori?

2012-09-07

218

Collective excitations in soft-sphere fluids  

NASA Astrophysics Data System (ADS)

Despite that the thermodynamic distinction between a liquid and the corresponding gas ceases to exist at the critical point, it has been recently shown that reminiscence of gaslike and liquidlike behavior can be identified in the supercritical fluid region, encoded in the behavior of hypersonic waves dispersion. By using a combination of molecular dynamics simulations and calculations within the approach of generalized collective modes, we provide an accurate determination of the dispersion of longitudinal and transverse collective excitations in soft-sphere fluids. Specifically, we address the decreasing rigidity upon density reduction along an isothermal line, showing that the positive sound dispersion, an excess of sound velocity over the hydrodynamic limit typical for dense liquids, displays a nonmonotonic density dependence strictly correlated to that of thermal diffusivity and kinematic viscosity. This allows rationalizing recent observation parting the supercritical state based on the Widom line, i.e., the extension of the coexistence line. Remarkably, we show here that the extremals of transport properties such as thermal diffusivity and kinematic viscosity provide a robust definition for the boundary between liquidlike and gaslike regions, even in those systems without a liquid-gas binodal line. Finally, we discuss these findings in comparison with recent results for Lennard-Jones model fluid and with the notion of the "rigid-nonrigid" fluid separation lines.

Bryk, Taras; Gorelli, Federico; Ruocco, Giancarlo; Santoro, Mario; Scopigno, Tullio

2014-10-01

219

Optically excited states in positronium  

NASA Technical Reports Server (NTRS)

Optical excitation are reported of the 1 3S-2 3P transition in positronium, and a second excitation from n=2 to higher n states. The experiment used light from two pulsed dye lasers. Changes in the positronium annihilation rate during and after the laser pulse were used to deduce the excited state populations. The n=2 level was found to be saturable and excitable to a substantial fraction of n=2 positronium to higher levels. Preliminary spectroscopic measurements were performed on n=14 and n=15 positronium.

Howell, R. H.; Ziock, Klaus P.; Magnotta, F.; Dermer, Charles D.; Failor, R. A.; Jones, K. M.

1990-01-01

220

Molecular dynamics of liquid benzene via femtosecond pulses laser excitation  

E-print Network

in polarizability modifications associated to molecular motions. Additionally, we present evidence that orientation for the molecules to orient along the incident field is measured. Revue Phys. Appl. 22 (1987) 1749-1753 D�CEMBRE access to orientation rise time of molecules. In this respect, C. Kalpouzos et al. argued for a « delay

Paris-Sud XI, Université de

221

Algebraic spin liquid in an exactly solvable spin model  

SciTech Connect

We have proposed an exactly solvable quantum spin-3/2 model on a square lattice. Its ground state is a quantum spin liquid with a half integer spin per unit cell. The fermionic excitations are gapless with a linear dispersion, while the topological 'vison' excitations are gapped. Moreover, the massless Dirac fermions are stable. Thus, this model is, to the best of our knowledge, the first exactly solvable model of half-integer spins whose ground state is an 'algebraic spin liquid.'

Yao, Hong; Zhang, Shou-Cheng; Kivelson, Steven A.; /Stanford U., Phys. Dept.

2010-03-25

222

Attosecond Photoscopy of Plasmonic Excitations  

NASA Astrophysics Data System (ADS)

We propose an experimental arrangement to image, with attosecond resolution, transient surface plasmonic excitations. The required modifications to state-of-the-art setups used for attosecond streaking experiments from solid surfaces only involve available technology. Buildup and lifetimes of surface plasmon polaritons can be extracted and local modulations of the exciting optical pulse can be diagnosed in situ.

Lupetti, Mattia; Hengster, Julia; Uphues, Thorsten; Scrinzi, Armin

2014-09-01

223

Market Liquidity and Funding Liquidity  

Microsoft Academic Search

We provide a model that links an asset's market liquidity (i.e., the ease with which it is traded) and traders' funding liquidity (i.e., the ease with which they can obtain funding). Traders provide market liquidity, and their ability to do so depends on their availability of funding. Conversely, traders' funding, i.e., their capital and margin requirements, depends on the assets'

Markus K. Brunnermeier; Lasse Heje Pedersen

2009-01-01

224

Coulomb excitation of 31Mg  

NASA Astrophysics Data System (ADS)

The ground state properties of 31Mg indicate a change of nuclear shape at N=19 with a deformed J=1/2 intruder state as a ground state, implying that 31Mg is part of the “island of inversion”. The collective properties of excited states were the subject of a Coulomb excitation experiment at REX-ISOLDE, CERN, employing a radioactive 31Mg beam. De-excitation ?-rays were detected by the MINIBALL ?-spectrometer in coincidence with scattered particles in a segmented Si-detector. The level scheme of 31Mg was extended. Spin and parity assignment of the 945 keV state yielded 5/2 and its de-excitation is dominated by a strong collective M1 transition. Comparison of the transition probabilities of 30,31,32Mg establishes that for the N=19 magnesium isotope not only the ground state but also excited states are largely dominated by a deformed pf intruder configuration.

Seidlitz, M.; Mücher, D.; Reiter, P.; Bildstein, V.; Blazhev, A.; Bree, N.; Bruyneel, B.; Cederkäll, J.; Clement, E.; Davinson, T.; Van Duppen, P.; Ekström, A.; Finke, F.; Fraile, L. M.; Geibel, K.; Gernhäuser, R.; Hess, H.; Holler, A.; Huyse, M.; Ivanov, O.; Jolie, J.; Kalkühler, M.; Kotthaus, T.; Krücken, R.; Lutter, R.; Piselli, E.; Scheit, H.; Stefanescu, I.; Van de Walle, J.; Voulot, D.; Warr, N.; Wenander, F.; Wiens, A.

2011-06-01

225

Excited waves in shear layers  

NASA Technical Reports Server (NTRS)

The generation of instability waves in free shear layers is investigated. The model assumes an infinitesimally thin shear layer shed from a semi-infinite plate which is exposed to sound excitation. The acoustical shear layer excitation by a source further away from the plate edge in the downstream direction is very weak while upstream from the plate edge the excitation is relatively efficient. A special solution is given for the source at the plate edge. The theory is then extended to two streams on both sides of the shear layer having different velocities and densities. Furthermore, the excitation of a shear layer in a channel is calculated. A reference quantity is found for the magnitude of the excited instability waves. For a comparison with measurements, numerical computations of the velocity field outside the shear layer were carried out.

Bechert, D. W.

1982-01-01

226

Phenomenological characterization of semiholographic non-Fermi liquids.  

PubMed

We analyze some phenomenological implications of the most general semiholographic models for non-Fermi liquids that have emerged with inputs from the holographic correspondence. We find generalizations of Landau-Silin equations with few parameters governing thermodynamics, low-energy response, and collective excitations. We show that even when there is a Fermi surface with well-defined quasiparticle excitations, the collective excitations can behave very differently from Landau's theory. PMID:24329436

Mukhopadhyay, Ayan; Policastro, Giuseppe

2013-11-27

227

Coulomb excitation of 107In  

NASA Astrophysics Data System (ADS)

The radioactive isotope 107In was studied using sub-barrier Coulomb excitation at the REX-ISOLDE facility at CERN. Two ? rays were observed during the experiment, corresponding to the low-lying 11/2+ and 3/2- states. The reduced transition probability of the 11/2+ state was determined with the semiclassical Coulomb excitation code gosia2. The result is discussed in comparison to large-scale shell-model calculations, previous unified-model calculations, and earlier Coulomb excitation measurements in the odd-mass In isotopes.

DiJulio, D. D.; Cederkall, J.; Fahlander, C.; Ekström, A.; Hjorth-Jensen, M.; Albers, M.; Bildstein, V.; Blazhev, A.; Darby, I.; Davinson, T.; De Witte, H.; Diriken, J.; Fransen, Ch.; Geibel, K.; Gernhäuser, R.; Görgen, A.; Hess, H.; Heyde, K.; Iwanicki, J.; Lutter, R.; Reiter, P.; Scheck, M.; Seidlitz, M.; Siem, S.; Taprogge, J.; Tveten, G. M.; Van de Walle, J.; Voulot, D.; Warr, N.; Wenander, F.; Wimmer, K.

2013-01-01

228

Effects of dark atom excitations  

E-print Network

New stable quarks and charged leptons may exist and be hidden from detection, as they are bound by Coulomb interaction in neutral dark atoms of composite dark matter. This possibility leads to fundamentally new types of indirect effects related to the excitation of such dark atoms followed by their electromagnetic de-excitation. Stable -2 charged particles, bound to primordial helium in O-helium (OHe) atoms, represent the simplest model of dark atoms. Here we consider the structure of OHe atomic levels which is a necessary input for the indirect tests of such composite dark matter scenarios, and we give the spectrum of electromagnetic transitions from the levels excited in OHe collisions.

Cudell, Jean-René; Wallemacq, Quentin

2014-01-01

229

Industrial applications of photonuclear resonance excitation  

E-print Network

Photonuclear resonance excitation refers to a variety of photonuclear interaction processes that lead to the excitation of a nucleus from some initial state to a higher energy nuclear state. Typical excited nuclear state ...

Chichester, David Lee, 1971-

2000-01-01

230

Exciting Students About Science & Engineering ...  

E-print Network

applications include nanomachines, bioimplants, smart materials, fuel cells, genetic engineering and spaceExciting Students About Science & Engineering ... ASM MATERIALS CAMP® 2013 MATERIALS IN TODAY'S WORLD Materials science and engineering is a study of the relationship between the structure

Evans, Paul G.

231

Multiphonon excitations in 62Zn  

NASA Astrophysics Data System (ADS)

We studied excited states in 62Zn up to an excitation energy of 5.5 MeV via the 61Ni( 3He, 2n ?) reaction at the Cologne Tandem accelerator with the high-efficiency HORUS cube spectrometer. We identified several multi-phonon excitations, especially two fragments of the one-phonon mixed-symmetry state 21,MS+ based on effective M1 and E2 transition strengths. The quantities were obtained from ?? angular correlation and Doppler-shift measurements. Shell-model calculations performed for 62Zn give clear support for the fragmentation of the one-phonon mixed-symmetry 21,MS+ state. The assumption of 62Zn being a vibrator-like nucleus is supported by calculations of excitation energies and E2 and M1 transition strengths within the U(5) limit of the neutron-proton Interacting Boson Model.

Albers, M.; Mücher, D.; Bernards, C.; Blazhev, A.; Fransen, C.; Heinze, S.; Jolie, J.; Lisetskiy, A.; Petkov, P.; Radeck, D.; Zell, K. O.

2010-12-01

232

Electron impact excitation of rubidium  

NASA Astrophysics Data System (ADS)

The electron energy-loss spectrum of rubidium at 40 eV and scattering angle 8° has been recorded. The noticeable features are analysed. Differential cross sections for the resonance excitation are determined.

Predojevi?, B.; Pej?ev, V.; Ševi?, D.; Leki?, S.; Srivastava, R.; Stauffer, A.; Marinkovi?, B. P.

2012-11-01

233

Exploring Liquids  

NSDL National Science Digital Library

Young learners investigate and observe the properties of three liquids -- water, vegetable oil, and corn syrup. They use their senses to collect data and ask and answer questions. This lesson for young learners introduces the scientific process.

Janulaw, Sharon

2010-01-01

234

Liquid penetrants  

NASA Technical Reports Server (NTRS)

Liquid-penetrant inspection is discussed for surface defects in solids. The principle advantages are considered to be its simplicity and economy. The techniques and penetrants are described along with the developers. Commercially available equipment is also described.

Pasley, R. L.

1973-01-01

235

Electron-excited molecule interactions  

SciTech Connect

In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10{sup 6} to 10{sup 7} times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs.

Christophorou, L.G. (Oak Ridge National Lab., TN (USA) Tennessee Univ., Knoxville, TN (USA). Dept. of Physics)

1991-01-01

236

Redox Control of Cardiac Excitability  

PubMed Central

Abstract Reactive oxygen species (ROS) have been associated with various human diseases, and considerable attention has been paid to investigate their physiological effects. Various ROS are synthesized in the mitochondria and accumulate in the cytoplasm if the cellular antioxidant defense mechanism fails. The critical balance of this ROS synthesis and antioxidant defense systems is termed the redox system of the cell. Various cardiovascular diseases have also been affected by redox to different degrees. ROS have been indicated as both detrimental and protective, via different cellular pathways, for cardiac myocyte functions, electrophysiology, and pharmacology. Mostly, the ROS functions depend on the type and amount of ROS synthesized. While the literature clearly indicates ROS effects on cardiac contractility, their effects on cardiac excitability are relatively under appreciated. Cardiac excitability depends on the functions of various cardiac sarcolemal or mitochondrial ion channels carrying various depolarizing or repolarizing currents that also maintain cellular ionic homeostasis. ROS alter the functions of these ion channels to various degrees to determine excitability by affecting the cellular resting potential and the morphology of the cardiac action potential. Thus, redox balance regulates cardiac excitability, and under pathological regulation, may alter action potential propagation to cause arrhythmia. Understanding how redox affects cellular excitability may lead to potential prophylaxis or treatment for various arrhythmias. This review will focus on the studies of redox and cardiac excitation. Antioxid. Redox Signal. 18, 432–468. PMID:22897788

Aggarwal, Nitin T.

2013-01-01

237

Wire deconstructionism of two-dimensional topological phases  

NASA Astrophysics Data System (ADS)

A scheme is proposed to construct integer and fractional topological quantum states of fermions in two spatial dimensions. We devise models for such states by coupling wires of nonchiral Luttinger liquids of electrons that are arranged in a periodic array. Which interwire couplings are allowed is dictated by symmetry and the compatibility criterion that they can simultaneously acquire a finite expectation value, opening a spectral gap between the ground state(s) and all excited states in the bulk. First, with these criteria at hand, we reproduce the tenfold classification table of integer topological insulators, where their stability against interactions becomes immediately transparent in the Luttinger liquid description. Second, we construct an example of a strongly interacting fermionic topological phase of matter with short-range entanglement that lies outside of the tenfold classification. Third, we expand the table to long-range entangled topological phases with intrinsic topological order and fractional excitations.

Neupert, Titus; Chamon, Claudio; Mudry, Christopher; Thomale, Ronny

2014-11-01

238

Velocity-modulation atomization of liquid jets  

NASA Technical Reports Server (NTRS)

A novel atomizer based on high-amplitude velocity atomization has been developed. Presently, the most common methods of atomization can use only the Rayleigh instability of a liquid cylinder and the Kelvin-Helmholtz instability of a liquid sheet. Our atomizer is capable of atomizing liquid jets by the excitation and destabilization of many other higher-order modes of surface deformation. The potential benefits of this sprayer are more uniform fuel air mixtures, faster fuel-air mixing, extended flow ranges for commercial nozzles, and the reduction of nozzle plugging by producing small drops from large nozzles.

Dressler, John L.

1994-01-01

239

Fission and Nuclear Liquid-Gas Phase Transition  

E-print Network

The temperature dependence of the liquid-drop fission barrier is considered, the critical temperature for the liquid-gas phase transition in nuclear matter being a parameter. Experimental and calculated data on the fission probability are compared for highly excited $^{188}$Os. The calculations have been made in the framework of the statistical model. It is concluded that the critical temperature for the nuclear liquid--gas phase transition is higher than 16 MeV.

E. A. Cherepanov; V. A. Karnaukhov

2007-03-30

240

Liquid Crystals  

NASA Technical Reports Server (NTRS)

Thermochromic liquid crystals, or TLCs, are a type of liquid crystals that react to changes in temperature by changing color. The Hallcrest/NASA collaboration involved development of a new way to visualize boundary layer transition in flight and in wind tunnel testing of aircraft wing and body surfaces. TLCs offered a new and potentially better method of visualizing the boundary layer transition in flight. Hallcrest provided a liquid crystal formulation technique that afforded great control over the sensitivity of the liquid crystals to varying conditions. Method is of great use to industry, government and universities for aerodynamic and hydrodynamic testing. Company's principal line is temperature indicating devices for industrial use, such as non-destructive testing and flaw detection in electric/electronic systems, medical application, such as diagnostic systems, for retail sale, such as room, refrigerator, baby bath and aquarium thermometers, and for advertising and promotion specials. Additionally, Hallcrest manufactures TLC mixtures for cosmetic applications, and liquid crystal battery tester for Duracell batteries.

1990-01-01

241

Orthogonal fluxgate employing discontinuous excitation  

NASA Astrophysics Data System (ADS)

In this work, we suggest a new method for the reduction of the power consumption of an orthogonal fluxgate employing an amorphous wire. In order to reduce the power consumption, we introduce idle intervals in the fluxgate excitation. In fluxgates where the excitation current is applied directly to the wire core, the excitation wave form can easily be manipulated due to the very small impedance of the wire core. The resulted discontinuities in the excitation increase the fluxgate noise by a factor of about 3.5. In order to eliminate this excess noise, we simply discard the data related to the excitation idle intervals from the signal processing of the fluxgate output. As a result, we have reduced the fluxgate power consumption by a factor of 16, from 6.4 mW at 100% duty cycle down to 0.4 mW at 6.25% duty cycle. It is important to note that the reduction of power consumption is obtained without decreasing the fluxgate resolution.

Weiss, Eyal; Paperno, Eugene; Plotkin, Anton

2010-05-01

242

Electrochemically induced actuation of liquid metal marbles  

NASA Astrophysics Data System (ADS)

Controlled actuation of soft objects with functional surfaces in aqueous environments presents opportunities for liquid phase electronics, novel assembled super-structures and unusual mechanical properties. We show the extraordinary electrochemically induced actuation of liquid metal droplets coated with nanoparticles, so-called ``liquid metal marbles''. We demonstrate that nanoparticle coatings of these marbles offer an extra dimension for affecting the bipolar electrochemically induced actuation. The nanoparticles can readily migrate along the surface of liquid metals, upon the application of electric fields, altering the capacitive behaviour and surface tension in a highly asymmetric fashion. Surprising actuation behaviours are observed illustrating that nanoparticle coatings can have a strong effect on the movement of these marbles. This significant novel phenomenon, combined with unique properties of liquid metal marbles, represents an exciting platform for enabling diverse applications that cannot be achieved using rigid metal beads.Controlled actuation of soft objects with functional surfaces in aqueous environments presents opportunities for liquid phase electronics, novel assembled super-structures and unusual mechanical properties. We show the extraordinary electrochemically induced actuation of liquid metal droplets coated with nanoparticles, so-called ``liquid metal marbles''. We demonstrate that nanoparticle coatings of these marbles offer an extra dimension for affecting the bipolar electrochemically induced actuation. The nanoparticles can readily migrate along the surface of liquid metals, upon the application of electric fields, altering the capacitive behaviour and surface tension in a highly asymmetric fashion. Surprising actuation behaviours are observed illustrating that nanoparticle coatings can have a strong effect on the movement of these marbles. This significant novel phenomenon, combined with unique properties of liquid metal marbles, represents an exciting platform for enabling diverse applications that cannot be achieved using rigid metal beads. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr00185g

Tang, Shi-Yang; Sivan, Vijay; Khoshmanesh, Khashayar; O'Mullane, Anthony P.; Tang, Xinke; Gol, Berrak; Eshtiaghi, Nicky; Lieder, Felix; Petersen, Phred; Mitchell, Arnan; Kalantar-Zadeh, Kourosh

2013-06-01

243

Excitation optimization for damage detection  

SciTech Connect

A technique is developed to answer the important question: 'Given limited system response measurements and ever-present physical limits on the level of excitation, what excitation should be provided to a system to make damage most detectable?' Specifically, a method is presented for optimizing excitations that maximize the sensitivity of output measurements to perturbations in damage-related parameters estimated with an extended Kalman filter. This optimization is carried out in a computationally efficient manner using adjoint-based optimization and causes the innovations term in the extended Kalman filter to be larger in the presence of estimation errors, which leads to a better estimate of the damage-related parameters in question. The technique is demonstrated numerically on a nonlinear 2 DOF system, where a significant improvement in the damage-related parameter estimation is observed.

Bement, Matthew T [Los Alamos National Laboratory; Bewley, Thomas R [UCSD

2009-01-01

244

Modeling Excitable Systems: Reentrant Tachycardia  

E-print Network

Excitable membranes are an important type of nonlinear dynamical system and their study can be used to provide a connection between physical and biological circuits. We discuss two models of excitable membranes important in cardiac and neural tissues. One model is based on the Fitzhugh-Nagumo equations and the other is based on a three-transistor excitable circuit. We construct a circuit that simulates reentrant tachycardia and its treatment by surgical ablation. This project is appropriate for advanced undergraduates as a laboratory capstone project, or as a senior thesis or honors project, and can also be a collaborative project, with one student responsible for the computational predictions and another for the circuit construction and measurements.

Jarrett L. Lancaster; Esther M. Leise; Edward H. Hellen

2008-07-02

245

Calculation of molecular excitation rates  

NASA Technical Reports Server (NTRS)

State-to-state collisional excitation rates for interstellar molecules observed by radio astronomers continue to be required to interpret observed line intensities in terms of local temperatures and densities. A problem of particular interest is collisional excitation of water which is important for modeling the observed interstellar masers. In earlier work supported by a different NASA Grant, excitation of water in collisions with He atoms was studied; after many years of successively more refined calculations that problem now seems to be well understood, and discrepancies with earlier experimental data for related (pressure broadening) phenomena are believed to reflect experimental errors. Because of interstellar abundances, excitation by H2, the dominant interstellar species, is much more important than excitation by He, although it has been argued that rates for excitation by these are similar. Under the current grant theoretical study of this problem has begun which is greatly complicated by the additional degrees of freedom which must be included both in determining the interaction potential and also in the molecular scattering calculation. We have now computed the interaction forces for nearly a thousand molecular geometries and are close to having an acceptable global fit to these points which is necessary for the molecular dynamics calculations. Also, extensive modifications have been made to the molecular scattering code, MOLSCAT. These included coding the rotational basis sets and coupling matrix elements required for collisions of an asymmetric top with a linear rotor. A new method for numerical solution of the coupled equations has been incorporated. Because of the long-ranged nature of the water-hydrogen interaction it is necessary to integrate the equations to rather large intermolecular separations, and the integration methods previously available in MOLSCAT are not ideal for such cases. However, the method used by Alexander in his HIBRIDON code is particularly suited for such cases. We have obtained this code and incorporated that part which solves the coupled differential equations as an option in the MOLSCAT program.

Flynn, George

1993-01-01

246

Autoresonant Excitation of Antiproton Plasmas  

SciTech Connect

We demonstrate controllable excitation of the center-of-mass longitudinal motion of a thermal antiproton plasma using a swept-frequency autoresonant drive. When the plasma is cold, dense, and highly collective in nature, we observe that the entire system behaves as a single-particle nonlinear oscillator, as predicted by a recent theory. In contrast, only a fraction of the antiprotons in a warm plasma can be similarly excited. Antihydrogen was produced and trapped by using this technique to drive antiprotons into a positron plasma, thereby initiating atomic recombination.

Andresen, G. B.; Bowe, P. D.; Hangst, J. S. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Ashkezari, M. D.; Hayden, M. E. [Department of Physics, Simon Fraser University, Burnaby British Columbia, V5A 1S6 (Canada); Baquero-Ruiz, M.; Chapman, S.; Fajans, J.; Povilus, A.; So, C. [Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300 (United States); Bertsche, W.; Butler, E.; Charlton, M.; Humphries, A. J.; Madsen, N.; Werf, D. P. van der [Department of Physics, Swansea University, Swansea SA2 8PP (United Kingdom); Carpenter, P. T.; Hurt, J. L.; Robicheaux, F. [Department of Physics, Auburn University, Auburn, Alabama 36849-5311 (United States); Cesar, C. L. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972 (Brazil)

2011-01-14

247

Electron impact excitation of coronene  

NASA Technical Reports Server (NTRS)

A preliminary study of the electron-impact excitation of thermally evaporated coronene at 550 C was carried out using electron-energy-loss spectroscopy. Measurements of the energy-loss spectra of coronene at high (100 eV) and low (5-20 eV) impact energies are presented. One of the high-energy spectra was converted to an apparent generalized oscillator strength spectrum and compared to the photoabsorption spectrum of coronene. Observations concerning vibrational excitation of coronene by electron impact are also presented and discussed.

Khakoo, M. A.; Ratliff, J. M.; Trajmar, S.

1990-01-01

248

Stochastic excitation of stellar oscillations  

E-print Network

Excitation of solar oscillations is attribued to turbulent motions in the solar convective zone. It is also currently believed that oscillations of low massive stars (M <2 Mo) - which possess an upper convective zone - are stochastically excited by turbulent convection in their outer layers. A recent theoretical work (Samadi & Goupil, 2001 ; Samadi et al, 2001) supplements and reinforces this theory. This allows the use of any available model of turbulence and emphasizes some recent unsolved problems which are brought up by these new theoretical developments.

Reza Samadi

2001-08-22

249

Geminate Recombination of alpha-Particle-Excited Carriers in Liguid Argon  

Microsoft Academic Search

We report experimental evidence showing that the electric-field-dependent yield of carriers excited in the track of an alpha particle stopping in liquid argon is dominated by geminate (initial) recombination of electron-ion pairs. This is the first confirmation of geminate carrier recombination in a noble-gas liquid. The thermalization length of the hot electrons is determined to be about 28 nm.

C. R. Gruhn; M. D. Edmiston

1978-01-01

250

Rocking response of tanks containing two liquids  

SciTech Connect

Liquid storage tanks are important components of industrial facilities and, when located in earthquake prone regions, should be designed to withstand the earthquakes to which they may be subjected. There are cases in which the density of the tank content is not uniform. For such cases, the dynamic responses of tanks containing liquids with different densities must be studied. A study on the dynamic response of upright circular cylindrical liquid-storage tanks containing two different liquids under a rock base motion with an arbitrary temporal variation is presented. Only rigid tanks were studied. The response quantities examined include the hydrodynamic pressure, sloshing wave height and the associated frequencies, base shear and moments. Each of these response quantities is expressed as the sum of the so-called impulsive component and convective component. Unlike the case of tanks containing one liquid, in which the response is controlled by one parameter, height-to-radius ratio, the response of tanks containing two different liquids are controlled by three parameters: height-to-radius ratio, and mass density ratio and height ratio of the two liquids. The interrelationship of the responses of the tank-liquid system to rocking and lateral base excitations is established by examining numerical results extensively. It is found that some of the response quantities for a tank-liquid system under a rocking base motion can be determined from the corresponding response quantities for an identical tank under a horizontal base motion.

Tang, Yu; Chang, Y.W.

1993-06-01

251

Liquid Hydrogen  

Microsoft Academic Search

THE letter of W. Hampson, which appears in your issue of May 26, can only mean by implication to charge me with having utilised without acknowledgment an idea of his, conveyed through a third party, in my paper on the liquid hydrogen jet, published in 1895. Such a suggestion is absolutely without any foundation in fact. My results would have

J. Dewar

1898-01-01

252

Excitations of Superfluid He4 Beyond the Roton  

NASA Astrophysics Data System (ADS)

Excitations of Superfluid ^4He Beyond the Roton. A. R. SAKHEL and H. R. GLYDE, University of Delaware - We present a Quantum Field Theoretical Model that reproduces the basic features of the temperature dependence of the dynamic structure factor S(Q,?) as observed in the inelastic-neutron scattering results at IRIS, (J.V. Pierce, R.T. Azuah, B.Fåk, A.R. Sakhel, H.R. Glyde, and W.G. Stirling, to be published.) UK. The range of the wavevector Q beyond the roton (Q > 2.0Åis considered. The model is able to simulate the decay of the excitations into two rotons when the excitation energy exceeds 2?, where ? is the roton energy. The model is based on the formulation of S(Q,?) of Gavoret and Nozières.(J. Gavoret and Nozières, Ann. Phys.), 28, 349-399 (1964). The component of dynamic susceptibility involving the condensate is modelled by an equation of the form: \\chis = n n_0(T) ? G ? where ? is a vertex, G the renormalized single particle Green's function, n the density of ^4He at SVP and n_0(T) the condensate fraction as a function of temperature. The dynamic susceptibility involving states above the condensate is modelled by a damped harmonic oscillator function.(H. R. Glyde, Excitation in Liquid and Solid Helium), Oxford, Clarendron Press (1994).

Sakhel, Asaad; Glyde, Henry

2001-03-01

253

Launch Excitement with Water Rockets  

ERIC Educational Resources Information Center

Explosions and fires--these are what many students are waiting for in science classes. And when they do occur, students pay attention. While we can't entertain our students with continual mayhem, we can catch their attention and cater to their desires for excitement by saying, "Let's make rockets." In this activity, students make simple, reusable…

Sanchez, Juan Carlos; Penick, John

2007-01-01

254

Materials modification by electronic excitation  

NASA Astrophysics Data System (ADS)

Electronic excitation by lasers or electron beams can modify the properties of materials. The changes are not just due to heat, nor do they result from the well-known collision dynamics of much radiation damage. Everyday examples of modification by electronic excitation include photography, and photochromics (such as sunglasses) which change colour. In the last few years it has become clear that excitation can offer novel types of modification, with better-controlled changes. The field has evolved through a mix of basic science, of new laser and electron beam tools, and of new needs from microelectronics, photonics and nanotechnology. Underlying this development are some common themes which integrate the basic science and its applications. These include especially the ideas of energy localisation and charge localisation. There are detailed comparisons of experiment and theory for halides, but there is a wealth of information for other materials. From this, we identify ways to connect understanding to technological needs, like selective removal of material, controlled changes, altering the balance between process steps, and possibilities of quantum control. The field is reviewed in full in our recent book [N. Itoh, A.M. Stoneham, Materials Modification by Electronic Excitation, Cambridge University Press, Cambridge, 2000].

Stoneham, A. M.; Itoh, Noriaki

2000-12-01

255

QUASIPERIODIC RESPONSE TO PARAMETRIC EXCITATIONS  

E-print Network

are reduced to systems of Mathieu-type equations (Mathieu [21]). These reductions are strictly only possible, this excitation of the free surface is described by the Mathieu equation (1.1) ij + (02 +a sinwt) rJ = 0, where 0 flat, mean position. This equation of Mathieu [21] has been studied extensively (see for example Jordan

Marques, Francisco

256

Communicating the Excitement of Science  

ScienceCinema

In this talk (which will include some exciting science) I will discuss some lessons I have learned about communicating science to scientists (in my own field and others), students, the public, the press, and policy makers in giving 500+ colloquia and seminars, 300+ public lectures and many informal presentations (including cocktail parties).

Michael Turner

2010-01-08

257

Dissociation of Highly Excited Molecules  

NASA Astrophysics Data System (ADS)

A survey of the spectroscopy and dynamics of the dissociation of highly excited molecules is presented with emphasis on superexcited molecules by electron- and photon-impact.(See review articles: a) Y. Hatano, The Physics of Electronic and Atomic Collisions, eds., L. J. Dube et al., AIP Press, New York (1995) pp.67-88; b) N.Kouchi et al., J. Phys. B, 30, 2319 (1997); c) Y. Hatano, Dynamics of Excited Molecules, ed., K. Kuchitsu, Elsevier, Amsterdam (1994) Chapter 6.) Topics will include newly developed experimental methods covering two-dimensional spectroscopy of photodissociation(M. Ukai et al., Phys. Rev. Lett., 74, 239 (1995).) (S. Machida et al., J. Phys. Chem. A. 101, 656 (1997).) (A. Ehresmann et al., J. Phys. B, 29, 3629 (1996).), and coincident electron-energy-loss spectroscopy of the dissociation dynamics of highly excited molecules.(T. Odagiri et al., J. Phys. B, 28, L465 (1995).)(T. Odagiri et al., J. Phys. B, 29, 1829 (1996).) The measurement of absolute photoionization quantum yields will also be discussed.(K. Kameta et al., J. Chem. Phys., 99, 2487 (1993).) Comparative studies of electron- and photon-impact dissociative excitation of molecules will be summarized. The molecules studied are H_2, N_2, O_2, CO, CO_2, N_2O, hydrocarbons, and some Si-containing compounds.

Hatano, Yoshihiko

1997-10-01

258

GO FURTHER... EXCITING OPPORTUNITIES TO  

E-print Network

work ethic. ...YOU WILL ALSO MAKE LIFELONG FRIENDS... HAVE THE MOST MEMORABLE EXPERIENCES... AND ENJOY the website for full details. SEE HOW FAR YOU CAN GO... Availability varies every year. Check out the websitefront GO FURTHER... EXCITING OPPORTUNITIES TO AQUIRE INTERNATIONAL EXPERIENCE See how far you can

Martin, Ralph R.

259

Capillary scale liquid core waveguide based fluorescence detectors for liquid chromatography and flow analysis  

Microsoft Academic Search

A versatile, simple, liquid core waveguide (LCW)-based fluorescence detector design is described for capillary systems. A Teflon AF coated fused silica capillary serves as the LCW. The LCW is transversely excited. The light source can be a conventional or high power (HP) light emitting diode (LED) or a laser diode (LD). The source can be coupled to the LCW directly

Guanqun Song; Ignacio Villanueva-Fierro; Shin-Ichi Ohira; Santosh Mishra; Howard Bailiff; Charles R. Savage; Purnendu K. Dasgupta

2008-01-01

260

Arrays and Cascades of Fluorescent Liquid-Liquid Waveguides: Broadband Light Sources for  

E-print Network

02138 This paper describes the fabrication and operation of fluidic broadband light sources for use "on) microchannel waveguides with liquid cores containing fluorescent dyes, excited by incident light from uses a cascade (series) of single-core, single- dye light sources of increasing absorption energy

Prentiss, Mara

261

Renormalization group analysis of thermal transport in the disordered Fermi liquid  

NASA Astrophysics Data System (ADS)

We present a detailed study of thermal transport in the disordered Fermi liquid with short-range interactions. At temperatures smaller than the impurity scattering rate, i.e., in the diffusive regime, thermal conductivity acquires nonanalytic quantum corrections. When these quantum corrections become large at low temperatures, the calculation of thermal conductivity demands a theoretical approach that treats disorder and interactions on an equal footing. In this paper, we develop such an approach by merging Luttinger's idea of using gravitational potentials for the analysis of thermal phenomena with a renormalization group calculation based on the Keldysh nonlinear sigma model. The gravitational potentials are introduced in the action as auxiliary sources that couple to the heat density. These sources are a convenient tool for generating expressions for the heat density and its correlation function from the partition function. Already in the absence of the gravitational potentials, the nonlinear sigma model contains several temperature-dependent renormalization group charges. When the gravitational potentials are introduced into the model, they acquire an independent renormalization group flow. We show that this flow preserves the phenomenological form of the correlation function, reflecting its relation to the specific heat and the constraints imposed by energy conservation. The main result of our analysis is that the Wiedemann-Franz law holds down to the lowest temperatures even in the presence of disorder and interactions and despite the quantum corrections that arise for both the electric and thermal conductivities.

Schwiete, G.; Finkel'stein, A. M.

2014-10-01

262

Liquid electrode  

DOEpatents

A dropping electrolyte electrode for use in electrochemical analysis of non-polar sample solutions, such as benzene or cyclohexane. The liquid electrode, preferably an aqueous salt solution immiscible in the sample solution, is introduced into the solution in dropwise fashion from a capillary. The electrolyte is introduced at a known rate, thus, the droplets each have the same volume and surface area. The electrode is used in making standard electrochemical measurements in order to determine properties of non-polar sample solutions.

Ekechukwu, Amy A. (Augusta, GA)

1994-01-01

263

Search for Intrinsic Excitations in 152Sm  

E-print Network

The 685 keV excitation energy of the first excited 0+ state in 152Sm makes it an attractive candidate to explore expected two-phonon excitations at low energy. Multiple-step Coulomb excitation and inelastic neutron scattering studies of 152Sm are used to probe the E2 collectivity of excited 0+ states in this "soft" nucleus and the results are compared with model predictions. No candidates for two-phonon K=0+ quadrupole vibrational states are found. A 2+, K=2 state with strong E2 decay to the first excited K=0+ band and a probable 3+ band member are established.

W. D. Kulp; J. L. Wood; P. E. Garrett; C. Y. Wu; D. Cline; J. M. Allmond; D. Bandyopadhyay; D. Dashdorj; S. N. Choudry; A. B. Hayes; H. Hua; M. G. Mynk; M. T. McEllistrem; C. J. McKay; J. N. Orce; R. Teng; S. W. Yates

2008-05-13

264

Backreaction of excitations on a vortex  

E-print Network

Excitations of a vortex are usually considered in a linear approximation neglecting their backreaction on the vortex. In the present paper we investigate backreaction of Proca type excitations on a straightlinear vortex in the Abelian Higgs model. We propose exact Ansatz for fields of the excited vortex. From initial set of six nonlinear field equations we obtain (in a limit of weak excitations) two linear wave equations for the backreaction corrections. Their approximate solutions are found in the cases of plane wave and wave packet type excitations. We find that the excited vortex radiates vector field and that the Higgs field has a very broad oscillating component.

Henryk Arodz; Leszek Hadasz

1996-07-15

265

Collective hypersonic excitations in strongly multiple scattering colloids.  

PubMed

Unprecedented low-dispersion high-frequency acoustic excitations are observed in dense suspensions of elastically hard colloids. The experimental phononic band structure for SiO(2) particles with different sizes and volume fractions is well represented by rigorous full-elastodynamic multiple-scattering calculations. The slow phonons, which do not relate to particle resonances, are localized in the surrounding liquid medium and stem from coherent multiple scattering that becomes strong in the close-packing regime. Such rich phonon-matter interactions in nanostructures, being still unexplored, can open new opportunities in phononics. PMID:21635048

Still, T; Gantzounis, G; Kiefer, D; Hellmann, G; Sainidou, R; Fytas, G; Stefanou, N

2011-04-29

266

Collective excitations in thin ^3He films  

NASA Astrophysics Data System (ADS)

The spectra for (longitudinal) collective excitations in thin polarized ^3He films are calculated from Fermi liquid theory. The calculation uses state-dependent Landau parameters that have been computed to quadratic order in s-wave and p-wave effective interaction components. The interaction components have been determined from existing spin susceptibility and specific heat measurements for ^3He adsorbed on graphite substrates and also in thin ^3He - superfluid ^4He films. The zero sound and spin-zero sound spectra as a function of density and polarization are obtained by solving Landau's kinetic equation. The matrix elements are computed exactly and analytically. The solutions contain partial wave contributions up to the l= 3 angular momentum components. In particular, we study features in the oscillation amplitudes of the two Fermi surfaces at finite polarization. We note that at this time there have been no direct measurements of sound speeds in ^3He films and so all of these results constitute predictions.

Li, David; Anderson, Roger; Miller, Michael

2011-10-01

267

Laser induced breakdown spectroscopy inside liquids: Processes and analytical aspects  

NASA Astrophysics Data System (ADS)

This paper provides an overview of the laser induced breakdown spectroscopy (LIBS) inside liquids, applied for detection of the elements present in the media itself or in the submerged samples. The processes inherent to the laser induced plasma formation and evolution inside liquids are discussed, including shockwave generation, vapor cavitation, and ablation of solids. Types of the laser excitation considered here are single pulse, dual pulse and multi-pulse. The literature relative to the LIBS measurements and applications inside liquids is reviewed and the most relevant results are summarized. Finally, we discuss the analytical aspects and release some suggestions for improving the LIBS sensitivity and accuracy in liquid environment.

Lazic, V.; Jovi?evi?, S.

2014-11-01

268

Excitation transport through Rydberg dressing  

NASA Astrophysics Data System (ADS)

We show how to create long-range interactions between alkali atoms in different hyperfine ground states, with the goal of coherent quantum transport. The scheme uses off-resonant dressing with atomic Rydberg states. We demonstrate coherent migration of electronic excitation through dressed dipole-dipole interaction by full solutions of models with four essential states per atom and give the structure of the spectrum of dressed states for a dimer. In addition, we present an effective (perturbative) Hamiltonian for the ground-state manifold and show that it correctly describes the full multi-state dynamics. We discuss excitation transport in detail for a chain of five atoms. In the presented scheme, the actual population in the Rydberg state is kept small. Dressing offers many advantages over the direct use of Rydberg levels: it reduces ionization probabilities and provides an additional tuning parameter for lifetimes and interaction strengths.

Wüster, S.; Ates, C.; Eisfeld, A.; Rost, J. M.

2011-07-01

269

Excitable behaviour in amoeboid chemotaxis  

PubMed Central

Chemotaxis, the directed motion of cells in response to chemical gradients, is a fundamental process. Eukaryotic cells detect spatial differences in chemoattractant receptor occupancy with high precision and use these differences to bias the location of actin-rich protrusions to guide their movement. Research into chemotaxis has benefitted greatly from a systems biology approach that combines novel experimental and computational tools to pose and test hypothesis. Recently, one such hypothesis has been postulated proposing that chemotaxis in eukaryotic cells is mediated by locally biasing the activity of an underlying excitable system. The excitable system hypothesis can account for a number of cellular behaviours related to chemotaxis, including the stochastic nature of the movement of unstimulated cells, the directional bias imposed by chemoattractant gradients, and the observed spatial and temporal distribution of signalling and cytoskeleton proteins. PMID:23757165

Shi, Changji

2013-01-01

270

Coulomb excitation and transfer reactions  

NASA Astrophysics Data System (ADS)

Using the ?-spectrometer GASP and the PYRAMID array of position sensitive particle counters enabled improved nuclear structure studies employing direct reactions. Coulomb excitation of 232Th by 58Ni at a beam energy of 265 MeV was used to investigate multi-phonon surface vibrations. For 232Th a new band has been found which is interpreted as harmonic two-phonon octupole vibrational band with K ?=0 +. The system 110Pd + 52Cr was chosen to study the mechanism of multinucleon transfer at energies in the vicinity of the Coulomb barrier. It was possible to identify 10 different transfer channels by their characteristic ?-decay. The total excitation energy versus ?-multiplicity correlations for the most prominent even-even transfer channels show a ‘cold’ component which is a strong indication for correlated pair transfer. For the 2n and 2p channel this fraction is 30(4)%, respectively 16(8)%.

Gerl, J.; Bazzacco, D.; Elze, Th. W.; Happ, T.; Härtlein, T.; Korten, W.; Kröll, T.; Napoli, D.; Alvarez, C. Rossi; Schubert, R.; Vetter, K.; Wollersheim, H. J.

271

Solitonlike excitations in biological systems  

NASA Astrophysics Data System (ADS)

A model for solitonlike excitation in DNA is presented and assessed in the context of previous models of collective excitations in other biological systems. A qualitative analysis describes the mechanisms of some DNA function, in particular opening of DNA base pairs to initiate protein synthesis. A formalism is presented which analyzes quantitatively the above-mentioned model, predicts the threshold for B-DNA-->A-DNA transition, and specifies the parameters of particular electromagnetic stimulations that can produce or initiate a variety of DNA responses and effects. The example of insulin production is discussed in detail and theoretical predictions are given for the parameters of an electromagnetic signal reproducing the stimulation to a cell which would lead to insulin production as a response.

Balanovski, Eduardo; Beaconsfield, Peter

1985-11-01

272

The rhythm of cortical excitability.  

PubMed

Evidence has been gained which suggests that the spectral properties of the excitability cycle are other than those first proposed or assumed to exist in a number of experiments and theories. Instead of appearing as a sinusoidal cycle at the alpha frequency, the excitability cycle seems to be irregular and slower on the average than the EEG alpha rhythm. The rhythm appears to be continuously operative. It is not very sensitive in its spectral composition to the conditions of illumination or the level of behavioral activity. The rhythm operates synchronously in the right and left visual cortex. Methods similar to those described here could be used to map the extent to which synchrony is maintained in structures throughout the brain. They also suggest new approaches for psycho-physical studies which are aimed at establishing relationships between behavioral or perceptual phenomena and measures of neural activity. PMID:6159153

Rudell, A

1980-07-01

273

Continuum excitations in 6He  

Microsoft Academic Search

The three-body breakup 6He-->4He+n+n is studied experimentally, using a secondary 6He ion beam of 240 MeV\\/nucleon incident on carbon and lead targets. Integrated cross sections for one- and two-neutron knockout and differential cross sections dsigma\\/dE* and dsigma\\/dvartheta for inelastic nuclear or electromagnetic excitations into the 6He continuum are presented. The E1-strength distribution is deduced from electromagnetic cross sections and is

T. Aumann; D V Aleksandrov; L. Axelsson; T. Baumann; M. J. Borge; L. V. Chulkov; J. Cub; W. Dostal; B. Eberlein; Th. W. Elze; H. Emling; H. Geissel; V. Z. Goldberg; M S Golovkov; A Grünschloss; M. Hellström; K. Hencken; J. Holeczek; R. Holzmann; B. Jonson; A. A. Korshenninikov; J. V. Kratz; G. Kraus; R. Kulessa; Y. Leifels; A. Leistenschneider; T E Leth; I. Mukha; G. Münzenberg; F. Nickel; T. Nilsson; G H Nyman; B. Petersen; M. Pfützner; A. Richter; K. Riisager; C. Scheidenberger; G. Schrieder; W. Schwab; H. Simon; M. H. Smedberg; M. Steiner; J. Stroth; A. Surowiec; T. Suzuki; O. Tengblad; M. V. Zhukov

1999-01-01

274

Self-excited multifractal dynamics  

NASA Astrophysics Data System (ADS)

We introduce the self-excited multifractal (SEMF) model, defined such that the amplitudes of the increments of the process are expressed as exponentials of a long memory of past increments. The principal novel feature of the model lies in the self-excitation mechanism combined with exponential nonlinearity, i.e. the explicit dependence of future values of the process on past ones. The self-excitation captures the microscopic origin of the emergent endogenous self-organization properties, such as the energy cascade in turbulent flows, the triggering of aftershocks by previous earthquakes and the "reflexive" interactions of financial markets. The SEMF process has all the standard stylized facts found in financial time series, which are robust to the specification of the parameters and the shape of the memory kernel: multifractality, heavy tails of the distribution of increments with intermediate asymptotics, zero correlation of the signed increments and long-range correlation of the squared increments, the asymmetry (called "leverage" effect) of the correlation between increments and absolute value of the increments and statistical asymmetry under time reversal.

Filimonov, V.; Sornette, D.

2011-05-01

275

Vibrationally excited hydroxyl tagging velocimetry.  

PubMed

A new molecular-based velocity method is developed for high-temperature flame gases based on the hydroxyl tagging velocimetry (HTV) technique. In vibrationally excited HTV (VE-HTV), two photons from a KrF laser (248 nm) dissociate H2O into a tag line of vibrationally excited OH (v=1). The excited state OH tag is selectively detected in a background of naturally occurring ground state OH (v=0). In atmospheric pressure laboratory burners, the OH (v=1) tag persists for 5-10 ?s, allowing single-shot velocity measurements along a 2 cm line under lean, stoichiometric, and rich flame conditions with temperatures reaching 2300 K. Mean velocity measurements are demonstrated in a lean (?=0.78) premixed H2/air turbulent flame (Re=26,550) laboratory flame. The VE-HTV method is best suited to measure high-speed velocities in hot combustion environments in the presence of background OH. PMID:25402874

Grady, Nathan; Pitz, Robert W

2014-11-01

276

The electromechanics of liquids electrowetting (EWOD) & liquid  

E-print Network

as the energy storage mechanism. Why does virtual work method work? dielectric liquid z We´ C #12;11 Pellat-emulsion droplets #12;4 The original experiment of Pellat 1895 Paris h + V - gravity dielectric liquid: , air: =1 ! h " (#liquid $1)%o Eo 2 2&liquid g #12;5 Quincke bubble method (1883) air bubble trapped between 2

Jones, Thomas B.

277

Laser-induced separation of hydrogen isotopes in the liquid phase  

DOEpatents

Hydrogen isotope separation is achieved by either (a) dissolving a hydrogen-bearing feedstock compound in a liquid solvent, or (b) liquefying a hydrogen-bearing feedstock compound, the liquid phase thus resulting being kept at a temperature at which spectral features of the feedstock relating to a particular hydrogen isotope are resolved, i.e., a clear-cut isotope shift is delineated, irradiating the liquid phase with monochromatic radiation of a wavelength which at least preferentially excites those molecules of the feedstock containing a first hydrogen isotope, inducing photochemical reaction in the excited molecules, and separating the reaction product containing the first isotope from the liquid phase.

Freund, Samuel M. (Los Alamos, NM); Maier, II, William B. (Los Alamos, NM); Beattie, Willard H. (Los Alamos, NM); Holland, Redus F. (Los Alamos, NM)

1980-01-01

278

On Diversity of Configurations Generated by Excitable Cellular Automata with Dynamical Excitation Intervals  

NASA Astrophysics Data System (ADS)

Excitable cellular automata with dynamical excitation interval exhibit a wide range of space-time dynamics based on an interplay between propagating excitation patterns which modify excitability of the automaton cells. Such interactions leads to formation of standing domains of excitation, stationary waves and localized excitations. We analyzed morphological and generative diversities of the functions studied and characterized the functions with highest values of the diversities. Amongst other intriguing discoveries we found that upper boundary of excitation interval more significantly affects morphological diversity of configurations generated than lower boundary of the interval does and there is no match between functions which produce configurations of excitation with highest morphological diversity and configurations of interval boundaries with highest morphological diversity. Potential directions of future studies of excitable media with dynamically changing excitability may focus on relations of the automaton model with living excitable media, e.g. neural tissue and muscles, novel materials with memristive properties and networks of conductive polymers.

Adamatzky, Andrew

2012-12-01

279

Excitation of slosh waves associated with low frequency impulsive reverse gravity acceleration of geyser initiation  

NASA Astrophysics Data System (ADS)

The objective of the cryogenic fluid management of the spacecraft propulsion system is to develop the technology necessary for acquisition or positioning of liquid and vapor within a tank in reduced gravity to enable liquid outflow or vapor venting. The requirement to settle or to position liquid fuel over the outlet end of the spacecraft propellant tank prior to main engine restart poses a microgravity fluid behavior problem. The purpose of the present study is to investigate the stability of the most efficient technique for propellant resettling through the minimization of propellant usage and weight penalties. In this study slosh wave excitation induced by the resettling flow field activated by 0.1 Hz low frequency, impulsive reverse gravity acceleration, during reorientation with the initiation of geyser for liquid fill levels of 30, 50, 65, 70 and 80 percent, have been studied. Characteristics of slosh waves with various frequencies excited are discussed. Slosh wave excitation shift the fluid mass distribution in the container which impose time dependent variations in spacecraft moment of inertia. This information is important for the spacecraft control during the course of liquid reorientation.

Hung, R. J.; Shyu, K. L.

1992-06-01

280

Liquid Rainbow  

NSDL National Science Digital Library

In this density activity, students determine the relative densities of five liquids and layer them atop one another in a straw. Directions for conducting the activity are included in addition to lists of the science process skills, complex reasoning strategies, and National Science Education Standards that relate to it. A brief explanation of the activity's science content and an assessment idea are also provided. This activity is part of a set called Whelmers that were designed to inspire students to think about science concepts.

Mid-continent Research for Education and Learning (McREL); Jacobs, Steve

2004-01-01

281

Two-photon excitation of aluminium phthalocyanines  

SciTech Connect

A demonstration is given of the feasibility of two-photon excitation of aluminium phthalocyanine and of the pharmaceutical preparation 'Fotosens', used in photodynamic therapy. The excitation source was an Nd:YAG laser emitting at the 1064 nm wavelength. The spectra of the two-photon-excited luminescence were obtained and the two-photon absorption cross sections were determined. (lasers in medicine)

Meshalkin, Yu P; Alfimov, E E; Makukha, V K [Novosibirsk State Technical University, Novosibirsk (Russian Federation); Vasil'ev, N E; Denisov, A N; Ogirenko, A P [Siberian Laser Medicine Centre, Novosibirsk (Russian Federation)

1999-12-31

282

Excited Quark Production at Future p Colliders  

Microsoft Academic Search

Excited quark production at future p colliders is studied. Namely, p ! q?X with subsequent q? ! gq and q decay channels are considered. Signatures for discovery of the excited quark and corresponding standard model backgrounds are discussed in detail. Discovery limits for excited quark masses and achievable values of compositeness parameters fs, f and fare determined.

R. Ciftci

283

Photoionization spectrum of liquid benzene  

SciTech Connect

The photocurrent from neat liquid benzene has been studied for excitation energies from threshold to 10.3 eV and for externally applied electric fields from 1 to 50 kV/cm. Using a power law fit to the energy dependence of the threshold current, an onset of [epsilon][sub t] = 7.65 [+-] 0.1 eV has been obtained. The field dependence was fit to an exponential radial probability density for thermalized ion-pair separation distances with an average separation distance of [r] = 23 [+-] 2 A at an excitation energy, [epsilon] of 8.86 eV (1.2 eV above threshold). Photocurrent was too weak to establish a dependence of [r] on excitation energy. The quantum yield for photocurrent at 8.86 eV was determined by comparison with the photocurrent from TMPD in 2,2,4-trimethylpentane (isooctane) to be 6.5 [times] 10[sup [minus]4] at zero field. From this, the intrinsic molecular ionization probability at [epsilon] = 8.86 eV was determined to be 0.6 [+-] 0.3. 30 refs., 5 figs.

Saik, V. O.; Lipsky, S. (Univ. of Minnesota, Minneapolis, MN (United States))

1994-11-17

284

Quantum Hall Liquid on a Noncommutative Superplane  

E-print Network

Supersymmetric quantum Hall liquids are constructed on a noncommutative superplane. We explore a supersymmetric formalism of the Landau problem. In the lowest Landau level, there appear spin-less bosonic states and spin-1/2 down fermionic states, which exhibit a super-chiral property. It is shown the Laughlin wavefunction and topological excitations have their superpartners. Similarities between supersymmetric quantum Hall systems and bilayer quantum Hall systems are discussed.

Kazuki Hasebe

2005-03-22

285

Theoretical studies of electronically excited states  

NASA Astrophysics Data System (ADS)

Time-dependent density functional theory is the most widely used quantum chemical method for studying molecules in electronically excited states. However, excited states can also be computed within Kohn-Sham density functional theory by exploitingmethods that converge the self-consistent field equations to give excited state solutions. The usefulness of single reference self-consistent field based approaches for studying excited states is demonstrated by considering the calculation of several types of spectroscopy including the infrared spectroscopy of molecules in an electronically excited state, the rovibrational spectrum of the NO-Ar complex, core electron binding energies and the emission spectroscopy of BODIPY in water.

Besley, Nicholas A.

2014-10-01

286

Rocking response of tanks containing two liquids  

SciTech Connect

A study on the dynamic response of upright circular cylindrical liquid-storage tanks containing two different liquids under a rocking base motion with an arbitrary temporal variation is presented. Only rigid tanks were studied. The response quantities examined include the hydrodynamic pressure, sloshing wave height and the associated frequencies, base shear and moments. Each of these response quantities is expressed as the sum of the so-called impulsive component and convective component. Unlike the case of tanks containing one liquid, in which the response is controlled by one parameter, height-to-radius ratio, the response of tanks containing two different liquids are controlled by three parameters: height-to-radius ratio, and mass density ratio and height ratio of the two liquids. The interrelationship of the responses of the tank-liquid system to rocking and lateral base excitations is established by examining numerical results extensively. The study shows that some of the response quantities for tank-liquid system under a rocking base motion can be determined from the available data for the response of an identical tank under a horizontal base motion. Base rocking motion can occur in a ground-supported tank or in an elevated tank under earthquake motions.

Tang, Y. [Argonne National Lab., IL (United States). Reactor Engineering Div.

1995-01-01

287

Topology regulates the distribution pattern of excitations in excitable dynamics on graphs  

NASA Astrophysics Data System (ADS)

We study the average excitation density in a simple model of excitable dynamics on graphs and find that this density strongly depends on certain topological features of the graph, namely connectivity and degree correlations, but to a lesser extent on the degree distribution. Remarkably, the average excitation density is changed via the distribution pattern of excitations: An increase in connectivity induces a transition from globally to locally organized excitations and, as a result, leads to an increase in the excitation density. A similar transition can be induced by increasing the rate of spontaneous excitations while keeping the graph architecture constant.

Müller-Linow, Mark; Marr, Carsten; Hütt, Marc-Thorsten

2006-07-01

288

New Modes of Nuclear Excitations  

NASA Astrophysics Data System (ADS)

We present a theoretical approach based on density functional theory supplemented by a microscopic multi-phonon model which is applied for investigations of pygmy resonances and other excitations of different multipolarities in stable and exotic nuclei. The possible relation of low-energy modes to the properties of neutron or proton skins is systematically studied in isotonic and isotopic chains. The fine structure of nuclear electric and magnetic response functions is analyzed and compared to experimental data. Their relevance to nuclear astrophysics is discussed.

Tsoneva, Nadia; Lenske, Horst

2014-03-01

289

Some mathematical problems of excitability.  

PubMed

The description of the electrical behaviour of nerve and muscle is one of the most quantitative areas of cellular physiology. There are detailed biophysical measurements of currents and potentials, that may be summarised as Master equations or stochastic differential equations for membrane channel and noise recordings, and nonlinear differential equations for macroscopic voltage clamp recordings. Propagation in excitable media is described by nonlinear reaction-diffusion equations. Computational approaches can provide solutions to these equations, but without qualitative studies on simplified caricatures contribute little to mathematical or physiological understanding. PMID:2082914

Holden, A V

1990-01-01

290

Ionic liquids as electrolytes  

Microsoft Academic Search

Salts having a low melting point are liquid at room temperature, or even below, and form a new class of liquids usually called room temperature ionic liquids (RTIL). Information about RTILs can be found in the literature with such key words as: room temperature molten salt, low-temperature molten salt, ambient-temperature molten salt, liquid organic salt or simply ionic liquid. Their

Maciej Gali?ski; Andrzej Lewandowski; Izabela St?pniak

2006-01-01

291

Guidance Document Cryogenic Liquids  

E-print Network

Guidance Document Cryogenic Liquids [This is a brief and general summary. Read the full MSDS for more details before handling.] Introduction: All cryogenic liquids are gases at normal temperature liquefies them. Cryogenic liquids are kept in the liquid state at very low temperatures. Cryogenic liquids

292

Ultrafast conversions between hydrogen bonded structures in liquid water observed by femtosecond x-ray spectroscopy  

E-print Network

bond structures in water via core-hole excitation. The oxygen K-edge of vibrationally excited water to produce quantitative structural models of liquid water.17,18 This approach has tried to link the pre- edge I , main-edge II , and postedge III regions indicated in Fig. 2 a to local water structures

293

Measurement of excited states in 40Si and evidence for weakening of the N=28 shell gap  

E-print Network

Excited states in 40Si have been established by detecting gamma-rays coincident with inelastic scattering and nucleon removal reactions on a liquid hydrogen target. The low excitation energy, 986(5) keV, of the 2+[1] state provides evidence of a weakening in the N=28 shell closure in a neutron-rich nucleus devoid of deformation-driving proton collectivity.

C. M. Campbell; N. Aoi; D. Bazin; M. D. Bowen; B. A. Brown; J. M. Cook; D. -C. Dinca; A. Gade; T. Glasmacher; M. Horoi; S. Kanno; T. Motobayashi; W. F. Mueller; H. Sakurai; K. Starosta; H. Suzuki; S. Takeuchi; J. R. Terry; K. Yoneda; H. Zwahlen

2006-08-15

294

Cosmology with liquid mirror telescopes  

NASA Technical Reports Server (NTRS)

Liquid mirrors provide an exciting means to obtain large optical telescopes for substantially lower costs than conventional technologies. The liquid mirror concept has been demonstrated in the lab with the construction of a diffraction limited 1.5 m mirror. The mirror surface, using liquid mercury, forms a perfect parabolic shape when the mirror cell is rotated at a uniform velocity. A liquid mirror must be able to support a heavy mercury load with minimal flexure and have a fundamental resonant frequency that is as high as possible, to suppress the amplitude of surface waves caused by small vibrations transmitted to the mirror. To minimize the transmission of vibrations to the liquid surface, the entire mirror rests on an air bearing. This necessitates the mirror cell being lightweight, due to the limited load capabilities of the air bearing. The mirror components must also have physical characteristics which minimize the effects of thermal expansion with ambient temperature fluctuations in the observatory. In addition, the 2.7 m mirror construction is designed so that the techniques used may be readily extended to the construction of large mirrors. To attain the goals of a lightweight, rigid mirror, a composite laminant construction was used. The mirror consists of a foam core cut to the desired parabolic shape, with an accuracy of a few mm. An aluminum hub serves as an anchor for the foam and skin, and allows precise centering of the mirror on the air bearing and drive system. Several plys of Kevlar, covered in an epoxy matrix, are then applied to the foam. A final layer of pure epoxy is formed by spin casting. This final layer is parabolic to within a fraction of a mm. An aluminum ring bonded to the circumference of the mirror retains the mercury, and incorporates stainless-steel hard-points for the attachment of balance weights.

Hogg, David W.; Gibson, Brad K.; Hickson, Paul

1993-01-01

295

Dual excitation multiphase electrostatic drive  

SciTech Connect

A novel electrostatic drive technology named Dual Excitation Multiphase Electrostatic Drive (DEMED) was presented. A basic DEMED consisted of two plastic films in which 3-phase parallel electrodes were embedded and was driven by a 3-phase ac excitation to the electrodes. Static characteristics of DEMED were calculated and tested and the results agreed very well. Three prototype motors of DEMED were fabricated using commercially available technique. The first prototype consisted of a single slider and stator and generated a linear motion with a slider`s motion range of about 5mm. It weighed 7g and generated a power of 1.6W and a thrust force of 4.4N. The second prototype consisted of 50 layer stack of linear motors, summing their outputs. It weighed 3.6kg and generated a propulsive force of 310N being powered with boosted commercial 3-phase electricity. The third prototype consisted of a rotor and a stator in which electrodes were arranged radially and generated rotational motion. The maximum power of 36mW was generated by the prototype weighing only 260mg for its rotor and stator. From the results of the numerical calculation, a practical design methodology for the motor was determined. An optimal design for a motor employing currently available material and fabrication techniques is provided as an example. Analyses predict that force generation over the interfacial area between the slider and stator of this motor would be 3,900N/m{sup 2}.

Niino, Toshiki [Inst. of Physical and Chemical Research, Wako, Saitama (Japan); Higuchi, Toshiro [Univ. of Tokyo (Japan); [Kanagawa Academy of Science and Technology, Kawasaki, Kanagawa (Japan); Egawa, Saku [Hitachi Ltd., Tsuchiura, Ibaraki (Japan). Mechanical Engineering Research Lab.

1995-12-31

296

Liquid-liquid-solid transition in viscoelastic liquids  

PubMed Central

Liquid-liquid-solid transitions (LLST) are known to occur in confined liquids, exist in supercooled liquids and emerge in liquids driven from equilibrium. Molecular dynamics (MD) simulations claim many successes in forecasting the phenomena. The transitions are also studied in the framework of thermodynamics based methods and minimalistic models. In here, the proposed approach is derived in the framework of continuum and includes spatial and temporal dynamic heterogeneities; the approach is meant to capture the material behavior at small scales. We conjecture that the liquid-like and solid-like behaviors are dissimilar enough for the two to be governed by different constitutive relations. In this way, we gain additional degree of freedom, which is found essential when predicting the transitional phenomena. As a result, we derive the LLST criteria for liquids in equilibrium, during steady flow and at transient conditions. Lastly, we forecast short-lived LLSTs in human blood during cardiac cycle. PMID:23429528

Zubelewicz, Aleksander

2013-01-01

297

Gross violation of the Wiedemann-Franz law in a quasi-one-dimensional conductor  

PubMed Central

When charge carriers are spatially confined to one dimension, conventional Fermi-liquid theory breaks down. In such Tomonaga–Luttinger liquids, quasiparticles are replaced by distinct collective excitations of spin and charge that propagate independently with different velocities. Although evidence for spin–charge separation exists, no bulk low-energy probe has yet been able to distinguish successfully between Tomonaga–Luttinger and Fermi-liquid physics. Here we show experimentally that the ratio of the thermal and electrical Hall conductivities in the metallic phase of quasi-one-dimensional Li0.9Mo6O17 diverges with decreasing temperature, reaching a value five orders of magnitude larger than that found in conventional metals. Both the temperature dependence and magnitude of this ratio are consistent with Tomonaga–Luttinger liquid theory. Such a dramatic manifestation of spin–charge separation in a bulk three-dimensional solid offers a unique opportunity to explore how the fermionic quasiparticle picture recovers, and over what time scale, when coupling to a second or third dimension is restored. PMID:21772267

Wakeham, Nicholas; Bangura, Alimamy F.; Xu, Xiaofeng; Mercure, Jean-Francois; Greenblatt, Martha; Hussey, Nigel E.

2011-01-01

298

Gross violation of the Wiedemann-Franz law in a quasi-one-dimensional conductor.  

PubMed

When charge carriers are spatially confined to one dimension, conventional Fermi-liquid theory breaks down. In such Tomonaga-Luttinger liquids, quasiparticles are replaced by distinct collective excitations of spin and charge that propagate independently with different velocities. Although evidence for spin-charge separation exists, no bulk low-energy probe has yet been able to distinguish successfully between Tomonaga-Luttinger and Fermi-liquid physics. Here we show experimentally that the ratio of the thermal and electrical Hall conductivities in the metallic phase of quasi-one-dimensional Li(0.9)Mo(6)O(17) diverges with decreasing temperature, reaching a value five orders of magnitude larger than that found in conventional metals. Both the temperature dependence and magnitude of this ratio are consistent with Tomonaga-Luttinger liquid theory. Such a dramatic manifestation of spin-charge separation in a bulk three-dimensional solid offers a unique opportunity to explore how the fermionic quasiparticle picture recovers, and over what time scale, when coupling to a second or third dimension is restored. PMID:21772267

Wakeham, Nicholas; Bangura, Alimamy F; Xu, Xiaofeng; Mercure, Jean-Francois; Greenblatt, Martha; Hussey, Nigel E

2011-01-01

299

Liquid Crystal Institute  

NSDL National Science Digital Library

The Liquid Crystal Institute website provides information on the interdisciplinary research and development of liquid crystal optoelectronic materials, technology, and consumer products. It provides basic information on what liquid crystals are as well as how they are made and used.

Institute, Liquid C.

2003-10-10

300

Liquid foams of graphene  

E-print Network

Liquid foams are dispersions of bubbles in a liquid. Bubbles are stabilized by foaming agents that position at the interface between the gas and the liquid. Most foaming agents, such as the commonly used sodium dodecylsulfate, ...

Alcazar Jorba, Daniel

2012-01-01

301

Lacerations - liquid bandage  

MedlinePLUS

... medical attention. If the cut is minor, a liquid bandage (liquid adhesive) can be used on the cut to ... the wound and help stop bleeding. Using a liquid bandage is quick and painless to apply. Skin ...

302

Liquid annulus  

NASA Technical Reports Server (NTRS)

It is shown that the specific impulse varies with the square root of the temperature and inversely with the square root of the molecular weight of the propellant. Typical values for specific impulse corresponding to various rocket concepts are shown. The Liquid Annulus core concept consists of a fuel element which will be arranged in a moderator block. The advantages as seen for the system are: high specific impulse; structural material will all run at low temperature; and lower fission product inventory because of evaporation. It is felt that this concept is worth at least a first look because of the promise of very high specific impulse. Because of the low thrust, one would probably need a cluster of engines. This is not necessarily bad because there would be some redundancy, but because of the low thrust one might have to refuel while running. Depending on the fuel vaporization, material can be included in the uranium that is injected as one is running along.

Ludewig, Hans

1991-01-01

303

Medium effects on the lowest 1( n, ?*) excitation of 1,2,3-triazine in water  

NASA Astrophysics Data System (ADS)

Solvent effects on the lowest 1( n, ?*) excitation of 1,2,3-triazine have been studied using a method previously developed for estimating solvent shifts of species that have strong specific interactions with the solvent. The liquid structures are obtained from Monte Carlo simulations on dilute aqueous solutions of 1,2,3-triazine. Three hydrogen bonds to the ground state are found to be consistent with observed solvent shifts, and hydrogen bonding to the excited state is shown to be strong with one linear hydrogen bond to each symmetric nitrogen atom. The calculations provide a molecular analysis of the solvent shifts of the triazines in dilute solutions.

Xie, Daiqian; Ma, Xiaohua; Zeng, Jun

2003-01-01

304

Final excitation energy of fission fragments  

SciTech Connect

We study how the excitation energy of the fully accelerated fission fragments is built up. It is stressed that only the intrinsic excitation energy available before scission can be exchanged between the fission fragments to achieve thermal equilibrium. This is in contradiction with most models used to calculate prompt neutron emission, where it is assumed that the total excitation energy of the final fragments is shared between the fragments by the condition of equal temperatures. We also study the intrinsic excitation-energy partition in statistical equilibrium for different level-density descriptions as a function of the total intrinsic excitation energy of the fissioning system. Excitation energies are found to be strongly enhanced in the heavy fragment, if the level density follows a constant-temperature behavior at low energies, e.g., in the composed Gilbert-Cameron description.

Schmidt, Karl-Heinz; Jurado, Beatriz [Centre d'Etudes Nucleaires de Bordeaux Gradignan (CENBG), CNRS/IN2P3, Chemin du Solarium, B.P. 120, F-33175 Gradignan (France)

2011-06-15

305

Topological insulators and quantum spin liquids  

NASA Astrophysics Data System (ADS)

In this paper we review some connections recently discovered between topological insulators and certain classes of quantum spin liquids, focusing on two and three spatial dimensions. In two dimensions we show the integer quantum Hall effect plays a key role in relating topological insulators and chiral spin liquids described by fermionic excitations, and we describe a procedure for “generating” a certain class of topological states. In three dimensions we discuss interesting relationships between certain quantum spin liquids and interacting “exotic” variants of topological insulators. We focus attention on better understanding interactions in topological insulators, and the phases nearby in parameter space that might result from moderate to strong interactions in the presence of strong spin-orbit coupling. We stress that oxides with heavy transition metal ions, which often host a competition between electron interactions and spin-orbit coupling, are an excellent place to search for unusual topological phenomena and other unconventional phases.

Fiete, Gregory A.; Chua, Victor; Kargarian, Mehdi; Lundgren, Rex; Rüegg, Andreas; Wen, Jun; Zyuzin, Vladimir

2012-02-01

306

Design evaluation: S-band exciters  

NASA Technical Reports Server (NTRS)

A design evaluation study was conducted to produce S-band exciter (SBE) system to provide a highly stable phase or modulated carrier for transmission to spacecraft. The exciter is part of an S-band receiver/exciter/ranging system at Spaceflight Tracking and Data Network (STDN) ground stations. The major features of the system are defined. Circuit diagrams of the electronic components are provided.

1974-01-01

307

Search for excited neutrinos in Z decay  

NASA Astrophysics Data System (ADS)

Excited neutrinos decaying into a neutrino and a photon are searched for in the ALEPH detector at LEP. No evidence is found for Z decay into v¯v ? or v¯ ?v ? final states. Upper limits are derived on excited neutrino couplings up to excited neutrino masses close to the Z mass. Lower limits on the v ? mass, independent of the v ? decay modes, are deduced from the total Z width.

Decamp, D.; Deschizeaux, B.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Alemany, R.; Crespo, J. M.; Delfino, M.; Fernandez, E.; Gaitan, V.; Garrido, Ll.; Mato, P.; Miguel, R.; Mir, Ll. M.; Orteu, S.; Pacheco, A.; Perlas, J. A.; Tubau, E.; Catanesi, M. G.; Creanza, D.; de Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Maggi, M.; Natali, S.; Nuzzo, S.; Quattromini, M.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Gao, Y.; Hu, H.; Huang, D.; Jin, S.; Lin, J.; Ruan, T.; Wang, T.; Wu, W.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhao, W.; Atwood, W. B.; Bird, F.; Blucher, E.; Bonvicini, G.; Bossi, F.; Bourotte, J.; Brown, D.; Burnett, T. H.; Drevermann, H.; Dydak, F.; Forty, R. W.; Grab, C.; Hagelberg, R.; Haywood, S.; Jost, B.; Kasemann, M.; Kellner, G.; Knobloch, J.; Lacourt, A.; Lehraus, I.; Lohse, T.; Marchioro, A.; Martinez, M.; Menary, S.; Minten, A.; Miotto, A.; Nash, J.; Palazzi, P.; Ranjard, F.; Redlinger, G.; Roth, A.; Rothberg, J.; Rotscheidt, H.; von Rüden, W.; St. Denis, R.; Schlatter, D.; Takashima, M.; Talby, M.; Taureg, H.; Tejessy, W.; Wachsmuth, H.; Wasserbaech, S.; Wheeler, S.; Wiedenmann, W.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Bardadin-Otwinowska, M.; Falvard, A.; El Fellous, R.; Gay, P.; Henrard, P.; Jousset, J.; Michel, B.; Montret, J.-C.; Pallin, D.; Perret, P.; Proriol, J.; Prulhière, F.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Møllerud, R.; Nilsson, B. S.; Petersen, G.; Efthymiopoulos, I.; Simopoulou, E.; Vayaki, A.; Badier, J.; Blondel, A.; Bonneaud, G.; Braems, F.; Brient, J. C.; Fouque, G.; Gamess, A.; Guirlet, R.; Rosowsky, A.; Rougé, A.; Rumpf, M.; Tanaka, R.; Videau, H.; Videau, I.; Candlin, D. J.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Ikeda, M.; Lannutti, J.; Levinthal, D.; Mermikides, M.; Sawyer, L.; Stimpfl, G.; Antonelli, A.; Baldini, R.; Bencivenni, G.; Bologna, G.; Campana, P.; Capon, G.; Chiarella, V.; D'Ettorre-Piazzoli, B.; Felici, G.; Laurelli, P.; Mannocchi, G.; Massimo-Brancacci, F.; Murtas, F.; Murtas, G. P.; Nicoletti, G.; Pepe-Altarelli, M.; Picchi, P.; Zografou, P.; Altoon, B.; Boyle, O.; Halley, A. W.; Ten Have, I.; Hearns, J. L.; Lynch, J. G.; Morton, W. T.; Raine, C.; Scarr, J. M.; Smith, K.; Thompson, A. S.; Brandl, B.; Braun, O.; Geiges, R.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E. E.; Maumary, Y.; Putzer, A.; Rensch, B.; Stahl, A.; Tittel, K.; Wunsch, M.; Belk, A. T.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Cattaneo, M.; Dornan, P. J.; Dugeay, S.; Greene, A. M.; Hassard, J. F.; Patton, S. J.; Sedgbeer, J. K.; Taylor, G.; Tomalin, I. R.; Wright, A. G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Bowdery, C. K.; Brodbeck, T. J.; Finch, A. J.; Foster, F.; Hughes, G.; Keemer, N. R.; Nuttall, M.; Rowlingson, B. S.; Sloan, T.; Snow, S. W.; Barczewski, T.; Bauerdick, L. A. T.; Kleinknecht, K.; Renk, B.; Roehn, S.; Sander, H.-G.; Schmelling, M.; Steeg, F.; Albanese, J.-P.; Aubert, J.-J.; Benchouk, C.; Bernard, V.; Bonissent, A.; Courvoisier, D.; Etienne, F.; Papalexiou, S.; Payre, P.; Pietrzyk, B.; Qian, Z.; Blum, W.; Cattaneo, P.; Cowan, G.; Dehning, B.; Dietl, H.; Fernandez-Bosman, M.; Jahn, A.; Lange, E.; Lütjens, G.; Lutz, G.; Männer, W.; Moser, H.-G.; Pan, Y.; Richter, R.; Schwarz, A. S.; Settles, R.; Stiegler, U.; Stierlin, U.; Thomas, J.; Bertin, V.; de Bouard, G.; Boucrot, J.; Callot, O.; Chen, X.; Cordier, A.; Davier, M.; Ganis, G.; Grivaz, J.-F.; Heusse, Ph.; Janot, P.; Journé, V.; Kim, D. W.; Lefrançois, J.; Lutz, A.-M.; Veillet, J.-J.; Zhang, Z.; Zomer, F.; Amendolia, S. R.; Bagliesi, G.; Batignani, G.; Bosisio, L.; Bottigli, U.; Bradaschia, C.; Ciocci, M. A.; Ferrante, I.; Fidecaro, F.; Foà, L.; Focardi, E.; Forti, F.; Giassi, A.; Giorgi, M. A.; Ligabue, F.; Lusiani, A.; Mannelli, E. B.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Sanguinetti, G.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Carter, J. M.; Green, M. G.; March, P. V.; Medcalf, T.; Saich, M. R.; Strong, J. A.; Thomas, R. M.; Wildish, T.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Edwards, M.; Fisher, S. M.; Harvey, J.; Jones, T. J.; Norton, P. R.; Salmon, D. P.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Klopfenstein, C.; Lançon, E.; Locci, E.; Loucatos, S.; Mirabito, L.; Monnier, E.; Perez, P.; Perrier, F.; Rander, J.; Renardy, J.-F.; Roussarie, A.; Schuller, J.-P.; Ashman, J. G.; Booth, C. N.; Combley, F.; Dinsdale, M.; Martin, J.; Parker, D.; Thompson, L. F.; Brandt, S.; Burkhardt, H.; Grupen, C.; Meinhard, H.; Neugebauer, E.; Schäfer, U.; Seywerd, H.; Apollinari, G.; Giannini, G.; Gobbo, B.; Liello, F.; Milotti, E.; Rolandi, L.; Bellantoni, L.; Boudreau, J. F.; Cinabro, D.; Conway, J. S.; Cowen, D. F.; Deweerd, A. J.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; Harton, J. L.; Hilgart, J.

1990-11-01

308

Development of a high-performance liquid chromatographic method for bioanalytical applications with sulpiride  

Microsoft Academic Search

An improved HPLC method using a silica gel column with fluorescence detection (excitation at 300 nm and emission at 365 nm) was developed for the determination of sulpiride concentrations in plasma. Analysis of sulpiride in plasma samples was simplified by a one-step liquid–liquid extraction after alkaline treatment of only 1 ml of plasma. The low limit of quantitation was 20

Ming-Chuan Huang; Hsiu-O Ho; Geng-Cheng Yeh; Wen-Ting Ke; Li-Chin Lin; T.-M Bruce Hsu; Ching-Cheng Kao; Ming-Thau Sheu

2001-01-01

309

Rydberg excitation of Bose-Einstein condensates  

E-print Network

Rydberg atoms provide a wide range of possibilities to tailor interactions in a quantum gas. Here we report on Rydberg excitation of Bose-Einstein condensed 87Rb atoms. The Rydberg fraction was investigated for various excitation times and temperatures above and below the condensation temperature. The excitation is locally blocked by the van der Waals interaction between Rydberg atoms to a density-dependent limit. Therefore the abrupt change of the thermal atomic density distribution to the characteristic bimodal distribution upon condensation could be observed in the Rydberg fraction. The observed features are reproduced by a simulation based on local collective Rydberg excitations.

Rolf Heidemann; Ulrich Raitzsch; Vera Bendkowsky; Björn Butscher; Robert Löw; Tilman Pfau

2007-10-30

310

Novelties of liquid–liquid–liquid phase transfer catalysis  

Microsoft Academic Search

Liquid–liquid–liquid phase transfer catalysis (L–L–L PTC) offers orders of magnitude intensification of rates of reaction and better selectivities than the biphasic PTC. The catalyst-rich middle phase is the main reaction phase. The etherification or alkoxylation of p-chloronitrobenzene (PCNB) was conducted by using alkanol and alkali instead of the metal alkoxide. A kinetic model is presented and validated.

G. D Yadav; Suguna S Naik

2001-01-01

311

LOW-DIMENSIONAL AND DISORDERED SYSTEMS Nonequilibrium plasmons and transport properties of a double-junction quantum  

E-print Network

The recent discovery of novel one-dimensional 1D conductors with non-Fermi liquid behaviors has inspired ex conductors is well described by the Luttinger liquid LL theory, a generaliza- tion of the Tomonaga each wire segment by a spinless Luttinger liquid. Within the sequential tunneling approach, we describe

Choi, Mahn-Soo

312

A versatile liquid-core/liquid-twin-cladding waveguide micro flow cell fabricated by rapid prototyping  

NASA Astrophysics Data System (ADS)

In this paper we present the design and operation of a micro flow cell comprising a liquid-core/liquid-twin-cladding waveguide for on-chip fluorescence spectroscopy based on evanescent field illumination. The application of an inner (sample) and outer cladding stream minimizes the sample volume for optical measurements and ensures the analyte position in the evanescent field for excitation at the core/cladding interface. The fiber-chip-coupled laser light is guided by the fluidic waveguide providing a uniform excitation along the analysis channel. Fluorescence intensity measurements of different sample solutions were conducted to illustrate the operational quality. The fluidics device is fabricated by laser microstereolithography in 1.5 h.

Rosenauer, M.; Vellekoop, M. J.

2009-10-01

313

Smoothed particle hydrodynamics (SPH) simulation of a tuned liquid damper  

Microsoft Academic Search

The roll motion response of a single degree of freedom (SDOF) structural system to which a rigid rectangular partially filled liquid tank has been attached is considered. The SDOF structural system with the empty tank is first described with a mathematical model and this model is validated by performing decay experiments as well as experiments in which periodic excitations are

Gabriele Bulian; Antonio Souto-Iglesias; Louis Delorme; Elkin Botia-Vera

2010-01-01

314

Electronic coupling responsible for energy transfer in columnar liquid crystals  

Microsoft Academic Search

Electronic coupling is the driving force for energy transfer in molecular materials and consists of several components. We determine the strength of dipolar\\/multipolar coupling and coupling due to orbital overlap for excitation transport in triphenylene columnar liquid crystals. We use time-resolved fluorescence spectroscopy and computer simulations. The fit of the experimental and simulated fluorescence decays reveals that the transfer process

Dimitra Markovitsi; Sylvie Marguet; Lazaros K. Gallos; Hervé Sigal; Philippe Millié; Panos Argyrakis; Helmut Ringsdorf; Sandeep Kumar

1999-01-01

315

The measurement of ultraweak liquid surface wave by laser interferometry  

Microsoft Academic Search

We describe a simple experiment on the interference of refraction light by ultraweak liquid surface wave at low frequency. The surface wave profile is generated by electrically driven vertical oscillations exciters. The high visibility and stable laser interference fringes were gathered experimentally. The theoretical light intensity distribution agrees well with the observations. In particular, we show the relation between the

Daobin Luo; Runcai Miao; Jianke Liu

316

Self-Destabilizing Mechanism of Circular Liquid Jet  

Microsoft Academic Search

Concluding this series of theoretical studies, a persistent self-excitation mechanism of most unstable capillary wave at the nozzle exit is proposed on the basis of the one-dimensional model developed in the first report. It is found that, once an unstable wave travels down from the nozzle exit, the most unstable Rayleigh wave is repeatedly developed for the newly issued liquid

Akira Umemura

2008-01-01

317

Electrokinetics over liquid/liquid interfaces  

NASA Astrophysics Data System (ADS)

Since liquid-liquid interfaces flow in response to an applied stress, one might expect electrokinetic flows at liquid-liquid interfaces to be significantly higher than over liquid-solid interfaces. The earliest predictions for the electrophoretic mobility of charged mercury drops -- distinct approaches by Frumkin and Levich (1946), and Booth (1951) -- differed by O(a/?D), where a is the radius of the drop and ?D is the Debye screening length. Seeking to reconcile this rather striking discrepancy, Levine (1973) showed double-layer polarization to be the key ingredient. Without a physical mechanism by which electrokinetic effects are enhanced, however, it is difficult to know how general the enhancement is -- whether it holds only for liquid metal surfaces, or more generally, for all liquid/liquid surfaces. By considering a series of systems in which a planar metal strip is coated with either a liquid metal or liquid dielectric, we show that the central physical mechanism behind the enhancement predicted by Frumkin and Levich (1946) is the presence of an unmatched electrical stress upon the electrolyte-liquid interface, which establishes a Marangoni stress on the droplet surface and drives it into motion. The source of the unbalanced electrokinetic stress on a liquid metal surface is clear -- metals represent equipotential surfaces, so no field exists to drive an equal and opposite force on the surface charge. This might suggest that liquid metals represent a unique system, since dielectric liquids can support finite electric fields, which might be expected to exert an electrical stress on the surface charge that balances the electric stress. We demonstrate, however, that electrical and osmotic stresses on relaxed double-layers internal to dielectric liquids precisely cancel, so that internal electrokinetic stresses generally vanish in closed, ideally polarizable liquids. The enhancement for liquid mercury drops can thus be expected quite generally over clean, ideally polarizable liquid drops. More broadly, the ability to reliably engineer liquid interfaces in microfluidic systems, then, may provide a path to significantly enhanced electrokinetic flows.

Squires, Todd M.

2011-11-01

318

Ionic Liquids Database- (ILThermo)  

National Institute of Standards and Technology Data Gateway

SRD 147 Ionic Liquids Database- (ILThermo) (Web, free access)   IUPAC Ionic Liquids Database, ILThermo, is a free web research tool that allows users worldwide to access an up-to-date data collection from the publications on experimental investigations of thermodynamic, and transport properties of ionic liquids as well as binary and ternary mixtures containing ionic liquids.

319

Traveling Through Different Liquids  

NSDL National Science Digital Library

Learners observe and record what happens when they manipulate bottles containing a liquid (water or corn syrup) and one or more objects (screw, nail, paper clip). They should observe differences in how quickly the objects fall in the different liquids. This lesson builds on what learners have studied in previous lessons, Exploring Liquids and Exploring How Liquids Behave.

Janulaw, Sharon

2010-01-01

320

Look-alike Liquids  

NSDL National Science Digital Library

Learners add drops of four liquids (water, alcohol, salt water, and detergent solution) to different surfaces and observe the liquids' behavior. Learners will see that liquids have characteristic properties which can be used for identification. In the related activity, " Developing Tests to Distinguish Between Similar-Looking Liquids" (see related resources), learners identify an unknown based on these properties.

Kessler, James H.; Galvan, Patricia M.

2007-01-01

321

Micro-dynamics in 2D Dusty Plasma Liquids  

NASA Astrophysics Data System (ADS)

We review the recent studies on the micro-dynamics in strongly coupled dust Coulomb liquids suspended in low pressure glow discharges. Under the interplay of stochastic thermal noise and Coulomb interaction, cooperative fast hopping strings and vortices excited from the small amplitude caged motion in the ordered lattice domains are the key cooperative excitations in the system. Their spatio-temporal statistical behaviors obey the similar generic power law scaling as sac type avalanche in coupled sub-excitable system under noise. The hopping can be further enhanced by the external stress and suppressed by the finite boundary. The liquid exhibits nonlinear viscoelastic response under high frequency AC shear drives and exhibits layering transition in a narrow gap down to a few molecular width. Travelling soliton-type micro-bubble can be formed through intense pulsed laser ablation.

Lai, Ying-Ju; Teng, Lee-Wen; Tu, Pie-San; Chu, Hong-Yu; I, Lin

2002-12-01

322

Emergent kinetics and fractionalized charge in 1D spin-orbit coupled flatband optical lattices.  

PubMed

Recent ultracold atomic gas experiments implementing synthetic spin-orbit coupling allow access to flatbands that emphasize interactions. We model spin-orbit coupled fermions in a one-dimensional flatband optical lattice. We introduce an effective Luttinger-liquid theory to show that interactions generate collective excitations with emergent kinetics and fractionalized charge, analogous to properties found in the two-dimensional fractional quantum Hall regime. Observation of these excitations would provide an important platform for exploring exotic quantum states derived solely from interactions. PMID:24702335

Lin, Fei; Zhang, Chuanwei; Scarola, V W

2014-03-21

323

Toward realistic effective models of quantum-Hall edges  

NASA Astrophysics Data System (ADS)

We have investigated the dynamical properties of edge excitations in the (fractional) quantum-Hall regime for a sharp confining potential, emphasizing the effects resulting from the presence of long-range interaction. Our study uses chiral-Luttinger-liquid models that are motivated by the close analogy between the physics of edge excitations and that of plasmons in quasi-one-dimensional electron systems. We find that incorporating realistic long-range interaction is especially important for multi-branch edges. Results are presented for the tunneling-IV-curve power-law exponent and the two-terminal conductance.

Zülicke, U.; MacDonald, A. H.

1998-01-01

324

Tuning the Pitch of a Wine Glass by Playing with the Liquid inside  

ERIC Educational Resources Information Center

It is well known that the pitch of the sound produced by an excited glass shell can be tuned by adding some liquid in it. In this paper, it will be proved that the distribution of the liquid inside the shell plays a crucial role in this frequency shift. Thus it provides another way to tune the pitch of the sound by modifying the liquid…

Courtois, Matthieu; Guirao, Boris; Fort, Emmanuel

2008-01-01

325

Higgs type excitations in cold atom systems  

NASA Astrophysics Data System (ADS)

Higgs type excitations are the excitations which give mass to particles. The Higgs type excitations has a critical role both in particle physics and condensed matter physics. In particle physics, the suspected Higgs boson has been found by the Large Hadron Collider (LHC) in 2012. In condensed matter physics, the Higgs type excitations relate to order phase of the system. In this review, we present an overview of recent studies on the Higgs type excitations both in non-interacting and interacting cold atom systems. First, in non-interacting cold atom system, by synthesizing artificial non-Abelian gauge potential, we demonstrate that when a non-Abelian gauge potential is reduced to Abelian potential, the Abelian part constructs spin-orbit coupling, and the non-Abelian part emerges Higgs excitations. Secondly, the Higgs excitations which are the reputed Higgs amplitude mode in interacting cold atom system are discussed. We review the theoretical model and the experimental detection of Higgs amplitude mode in two dimensional superfluid. The observation of both Higgs type excitations in real experiments are also discussed.

Huang, FeiJie; Chen, QiHui; Liu, WuMing

2013-12-01

326

Excitation of helium ion by positron impact  

SciTech Connect

Three (1s,2s,2p) and five (1s,2s,2p,3s-bar,3p-bar) -state close-coupling methods have been employed to calculate the n = 2 excitation cross sections of helium ion by positron impact. The effect of pseudostate is found to be very pronounced in the case of 1s-2s excitation.

Khan, P.; Ghosh, A.S.

1986-01-01

327

Focus Issue: Getting Excited About Glia  

NSDL National Science Digital Library

This Focus Issue of Science Signaling complements the Science Special Issue and highlights glial cell function, development, and disease. This issue draws attention to the molecular mechanisms of drug resistance of a cancer of glial origin, and to signaling between glia and neurons. Although glia may not be excitable, they are clearly an exciting group of cells.

Elizabeth M. Adler (American Association for the Advancement of Science;Science Signaling REV)

2010-11-09

328

Vibrationally Excited Molecular Hydrogen near Herschel 36  

NASA Astrophysics Data System (ADS)

We present the first high resolution UV spectra toward Herschel 36, a Trapezium-like system of high-mass stars contained within the Lagoon Nebula (M8, NGC 6523). The spectra reveal extreme rovibrational excitation of molecular hydrogen in material at a single velocity or very small range of velocities, with this component presumably lying near the star system and undergoing fluorescent excitation. The overall H2 excitation is similar to, but apparently larger than, that seen toward HD 37903 which previously showed the largest vibrationally excited H2 column densities seen in UV absorption spectra. While the velocities of the highly excited H2 lines are consistent within each observation, it appears that they underwent a ~60 km s-1 redshift during the 3.6 yr between observations. In neither case does the velocity of the highly excited material match the velocity of the bulk of the line-of-sight material which appears to mostly be in the foreground of M8. Recent work shows unusually excited CH and CH+ lines and several unusually broad diffuse interstellar bands toward Herschel 36. Along with the H2 excitation, all of these findings appear to be related to the extreme environment within ~0.1 pc of the massive young stellar system.

Rachford, Brian L.; Snow, Theodore P.; Ross, Teresa L.

2014-05-01

329

Multiphoton excited fluorescence spectroscopy of biomolecular systems  

Microsoft Academic Search

Recent work on the emerging application of multiphoton excitation to fluorescence studies of biomolecular dynamics and structure is reviewed. The fundamental principles and experimental techniques of multiphoton excitation are outlined, fluorescence lifetimes, anisotropy and spectra in membranes, proteins, hydrocarbons, skin, tissue and metabolites are featured, and future opportunities are highlighted.

David J. S. Birch

2001-01-01

330

Laser-excited synchronous luminescence spectroscopy  

Microsoft Academic Search

The use of lasers as excitation sources for molecular luminescence often results in improvements in sensitivity and limits of detection (LODs). Synchronous luminescence (SL) spectroscopy, in which both excitation and emission wavelengths are scanned simultaneously, provides a convenient means to improve selectivity (often dramatically) in the analysis of multicomponent mixtures using room-temperature luminescence. The authors report here on the first

Christopher L. Stevenson; Tuan Vo-Dinh

1993-01-01

331

Discharge excitation of dye vapors  

NASA Astrophysics Data System (ADS)

Experiments have been conducted to assess the feasibility of obtaining a discharge-pumped dye vapor laser. A 15 (or 50) cm active length, UV-preionized device has been developed which exhibits a specific power loading of the medium of approx. 5 MW/cu cm and will operate continuously at temperatures exceeding 400 C. Recently, hydrogen thyratron switching of the device and corona preionization have been installed to minimize jitter and dye fragmentation. Optimization of the rare gas/N2 diluent mixture has been completed and fragmentation studies for several dye molecules have been conducted. POPOP and alpha-NPO are excellent in the latter regard but Coumarin 6 rapidly decomposes in the discharge environment. The fluorescence efficiency of alpha-NPO is only 40 percent of that for POPOP under comparable conditions. BBO and PBBO are similar in structure and molecular weight to POPOP and appear to be excellent candidates for discharge excitation. Fluorescence and small signal gain measurements are in progress.

Eden, J. G.

1987-09-01

332

Multi-photon excitation microscopy  

PubMed Central

Multi-photon excitation (MPE) microscopy plays a growing role among microscopical techniques utilized for studying biological matter. In conjunction with confocal microscopy it can be considered the imaging workhorse of life science laboratories. Its roots can be found in a fundamental work written by Maria Goeppert Mayer more than 70 years ago. Nowadays, 2PE and MPE microscopes are expected to increase their impact in areas such biotechnology, neurobiology, embryology, tissue engineering, materials science where imaging can be coupled to the possibility of using the microscopes in an active way, too. As well, 2PE implementations in noninvasive optical bioscopy or laser-based treatments point out to the relevance in clinical applications. Here we report about some basic aspects related to the phenomenon, implications in three-dimensional imaging microscopy, practical aspects related to design and realization of MPE microscopes, and we only give a list of potential applications and variations on the theme in order to offer a starting point for advancing new applications and developments. PMID:16756664

Diaspro, Alberto; Bianchini, Paolo; Vicidomini, Giuseppe; Faretta, Mario; Ramoino, Paola; Usai, Cesare

2006-01-01

333

Liquids intermediate between "molecular" and "ionic" liquids: liquid ion pairs?  

PubMed

Ionic liquids comprised of tetradecyltrihexyl- and tetrabutyl-phosphonium cations paired with chloride or sulfonyl amide anions exhibit properties that reflect strong ion association, including comparatively low viscosity as well as a degree of volatility, and hence exemplify an interesting intermediate state between true ionic and true molecular liquids. PMID:18217657

Fraser, Kevin J; Izgorodina, Ekaterina I; Forsyth, Maria; Scott, Janet L; MacFarlane, Douglas R

2007-10-01

334

Effect of baffle on the asymmetric gravity jitter excited slosh waves in microgravity  

NASA Technical Reports Server (NTRS)

The paper investigates the dynamical behavior of fluids affected by asymmetric gravity jitter oscillations, in particular, the effect of surface tension on partially filled rotating fluids in a full-scale Gravity Probe-B Spacecraft dewar tank, with and without the installation of the baffle-board, imposed by time-dependent directions of background gravity. The time-sequence evolution of the 3D behavior of the liquid-vapor interface oscillations resulting in the excitation of large amplitude slosh waves exerted by gravity jitter disturbances are examined. It is shown that the damping effect provided by baffle reduces the amplitude of slosh wave excitation and lowers the degree of asymmetry in the liquid-vapor distribution.

Hung, R. J.; Lee, C. C.; Leslie, F. W.

1993-01-01

335

Excited States of Non-Isolated Chromophores  

NASA Astrophysics Data System (ADS)

The photophysical and photochemical behavior of nucleobases is very important because of their biological role as the building blocks in DNA and RNA. Great progress has been made in understanding the excited-state properties of single bases. In order to understand the photophysical properties of nucleobases in complex environments we have investigated their excited states (a) in aqueous solutions and (b) as ?-stacked dimers in DNA. The solvatochromic shifts of the excited states of pyrimidine nucleobases in aqueous solution have been investigated using a combined QM/MM procedure where the quantum mechanical solute is described using high level multireference configuration interaction methods while molecular dynamics simulations are used to obtain the structure of the solvent around the solute in an average way. The excited states of ?-stacked nucleobases have also been investigated using various ab initio methods. The effect of the environment on the excited states and conical intersections is investigated.

Matsika, S.; Kozak, C.; Kistler, K.

2009-06-01

336

Gravity jitter induced slosh waves in liquid propellant and disturbances of fluid stresses on spacecraft  

NASA Technical Reports Server (NTRS)

The paper investigates the dynamical behavior of fluids, in particular the effect of surface tension on partially filled rotating fluids (cryogenic liquid helium and helium vapor) in a full-scale Gravity Probe-B spacecraft propellant dewar tank imposed by various frequencies of gravity jitters. Fluid stress distribution caused by the excitation of slosh waves and their associated large amplitude disturbances on the liquid-vapor interface and exerted on the outer and inner walls of a rotating dewar container are also examined. It is shown that fluid stress distributions near the outer and inner walls of the rotating dewar are closely related to the characteristics of slosh waves excited in the liquid-vapor interface in the rotating dewar tank. This can be of utility in managing spacecraft dynamic control leading to control of spacecraft imbalance caused by the uneven fluid stress distribution due to slosh wave excitations at the interface between liquid and vapor propellants.

Hung, R. J.; Lee, C. C.; Leslie, F. W.

1992-01-01

337

Impact of ground- and excited-state aromaticity on cyclopentadiene and silole excitation energies and excited-state polarities.  

PubMed

A new qualitative model for estimating the properties of substituted cyclopentadienes and siloles in their lowest ??* excited states is introduced and confirmed through quantum chemical calculations, and then applied to explain earlier reported experimental excitation energies. According to our model, which is based on excited-state aromaticity and antiaromaticity, siloles and cyclopentadienes are cross-hyperconjugated "aromatic chameleons" that adapt their electronic structures to conform to the various aromaticity rules in different electronic states (Hückel's rule in the ?(2) electronic ground state (S0) and Baird's rule in the lowest ??* excited singlet and triplet states (S1 and T1)). By using pen-and-paper arguments, one can explain polarity changes upon excitation of substituted cyclopentadienes and siloles, and one can tune their lowest excitation energies by combined considerations of ground- and excited-state aromaticity/antiaromaticity effects. Finally, the "aromatic chameleon" model can be extended to other monocyclic compound classes of potential use in organic electronics, thereby providing a unified view of the S0, T1, and S1 states of a range of different cyclic cross-?-conjugated and cross-hyperconjugated compound classes. PMID:25043523

Jorner, Kjell; Emanuelsson, Rikard; Dahlstrand, Christian; Tong, Hui; Denisova, Aleksandra V; Ottosson, Henrik

2014-07-21

338

Tip-enhanced Raman spectroscopy mapping with strong longitudinal field excitation  

NASA Astrophysics Data System (ADS)

Longitudinal electric field illumination is greatly effective for enhancing the local electric field and Raman signal at the tip apex in tip-enhanced Raman spectroscopy (TERS). In this work, the optical field distribution of tightly focused radially polarized (RP) beam on the focal plane is calculated according to vector diffraction theory and the effectiveness of longitudinal field excitation on Raman signal enhancement is experimentally verified. An RP beam generated by a liquid crystal spatial light modulator is focused via a high numerical-aperture objective lens to form a strong longitudinal electric field at the focus. The focused field is utilized to excite single-walled nanotubes sample in TERS experiments. The experimental results demonstrate that the enhancement factor of RP excitation is obviously higher compared with linearly polarized illumination. And then, the corresponding TERS mapping and topography are simultaneously characterized.

Zhang, M.; Wang, J.; Tian, Q.

2014-03-01

339

Electro-optical parameters in excited states of some spectrally active molecules  

NASA Astrophysics Data System (ADS)

The spectral shifts measured in different solvents are expressed as functions of the solvent macroscopic parameters. The value of the correlation coefficient multiplying the functions of electric permittivity was determined by statistical means. The correlation coefficient depends on the electric dipole moment of the spectrally active molecules. The electro-optical parameters in the ground state of the solute molecules can be approximated by molecular modeling. The excited state parameters are usually estimated using the results obtained both by HyperChem Programme and solvatochromic study. The importance of this approximate method is that it offers information about of the excited state of solute molecule for which our measuring possibilities are very restrictive. The information about the excited electronic state is affected by the limits in which the theories of liquid solutions are developed. Our results refer to two molecules of vitamins from B class, namely B3 and B6.

Benchea, Andreea Celia; Closca, Valentina; Rusu, Cristina Marcela; Morosanu, Cezarina; Dorohoi, Dana Ortansa

2014-08-01

340

Unbound excited states in 19,17C  

E-print Network

The neutron-rich carbon isotopes 19,17C have been investigated via proton inelastic scattering on a liquid hydrogen target at 70 MeV/nucleon. The invariant mass method in inverse kinematics was employed to reconstruct the energy spectrum, in which fast neutrons and charged fragments were detected in coincidence using a neutron hodoscope and a dipole magnet system. A peak has been observed with an excitation energy of 1.46(10) MeV in 19C, while three peaks with energies of 2.20(3), 3.05(3), and 6.13(9) MeV have been observed in 17C. Deduced cross sections are compared with microscopic DWBA calculations based on p-sd shell model wave functions and modern nucleon-nucleus optical potentials. Jpi assignments are made for the four observed states as well as the ground states of both nuclei.

Y. Satou; T. Nakamura; N. Fukuda; T. Sugimoto; Y. Kondo; N. Matsui; Y. Hashimoto; T. Nakabayashi; T. Okumura; M. Shinohara; T. Motobayashi; Y. Yanagisawa; N. Aoi; S. Takeuchi; T. Gomi; Y. Togano; S. Kawai; H. Sakurai; H. J. Ong; T. K. Onishi; S. Shimoura; M. Tamaki; T. Kobayashi; H. Otsu; Y. Matsuda; N. Endo; M. Kitayama; M. Ishihara

2007-12-26

341

Unbound excited states in $^{19}$,$^{17}$C  

E-print Network

The neutron-rich carbon isotopes 19,17C have been investigated via proton inelastic scattering on a liquid hydrogen target at 70 MeV/nucleon. The invariant mass method in inverse kinematics was employed to reconstruct the energy spectrum, in which fast neutrons and charged fragments were detected in coincidence using a neutron hodoscope and a dipole magnet system. A peak has been observed with an excitation energy of 1.46(10) MeV in 19C, while three peaks with energies of 2.20(3), 3.05(3), and 6.13(9) MeV have been observed in 17C. Deduced cross sections are compared with microscopic DWBA calculations based on p-sd shell model wave functions and modern nucleon-nucleus optical potentials. Jpi assignments are made for the four observed states as well as the ground states of both nuclei.

Satou, Y; Fukuda, N; Sugimoto, T; Kondo, Y; Matsui, N; Hashimoto, Y; Nakabayashi, T; Okumura, T; Shinohara, M; Motobayashi, T; Yanagisawa, Y; Aoi, N; Takeuchi, S; Gomi, T; Togano, Y; Kawai, S; Sakuraï, H; Ong, H J; Onishi, T K; Shimoura, S; Tamaki, M; Kobayashi, T; Otsu, H; Matsuda, Y; Endo, N; Kitayama, M; Ishihara, M

2008-01-01

342

Prediction of Sloshing and Seismic Response of a Floating Roof in a Cylindrical Liquid Storage Tank by the Response Spectrum Method  

Microsoft Academic Search

A response spectrum method is proposed to predict the sloshing response of a floating roof in a cylindrical liquid storage tank under seismic excitation. The liquid is assumed to be inviscid, incompressible, and irrotational, while the floating roof is considered as an orthotropic elastic plate of variable thickness. The dynamic interaction between the liquid and the floating roof is taken

Tetsuya Matsui

343

J. Phys. II France 6 (1996) 355-373 MARCH 1996, PAGE 355 From Bubble Domains to Spirals in Cholesteric Liquid Crystals  

E-print Network

cristal liquide tend vets z4ro. 1. Introduction The formation of spiral waves in excitable media is one in Cholesteric Liquid Crystals S. Pirkl (*) and P. Oswald (**) E-N-S- Lyon, Laboratoire de Physique (***), 46 November1995, accepted 12 December 1995) PACS.61.30.Gd Orientational of liquid crystals; electric

Boyer, Edmond

344

Fast Laser Excitation and Ultrahigh Strain-Rate Deformation  

SciTech Connect

Phase evolution induced by single or repeated excitation with energetic femtosecond laser pulses is examined. Of primary interest is the solidification behavior of pure metals at deep undercoolings and self-organization in simple eutectic alloys. Time resolved measurements using third harmonic generation (THG) of light and ultrafast electron diffraction (UED) are employed to elucidate several issues related to fast laser excitation, including heat transport by ballistic and diffusional electrons through multilayer films, the dependence of crystallization velocities on materials properties, mechanisms controlling the transport of heat away from the crystal-liquid interface, and the possibility for quenching pure metals, such as Cu, Ni, and Fe, into the amorphous state. Special samples designed to maximize the quenching speed are developed. The properties of such pure metallic glasses, such as glass and crystallization temperatures, will be measured, if such samples are successfully produced. The measurements are complemented by molecular dynamics computer simulations of the solidification process. The second interest of this research is mesoscopic, self-organization of materials under repeated laser melting, with diffusional relaxation between pulses. We select binary alloys that are immiscible in the solid state but miscible in the liquid state, such as Ag-Cu. Femtosecond laser irradiation is employed to induce melting and to vary the melting time over a wide range, from a few ps to hundreds of ps. This enables us to perform critical experimental tests of key theoretical predictions self-organization in alloys under external forcing, in particular the existence of a threshold value of the forced mixing length for patterning to take place.

Robert Averback

2007-06-03

345

Interfacial Phenomena of Magnetic Fluid with Permanent Magnet in a Longitudinally Excited Container  

SciTech Connect

This paper describes the magnetic fluid sloshing in a longitudinally excited container. Liquid responses of magnetic fluid with a permanent magnet in a circular cylindrical container subject to vertical vibration are investigated. Experiments are performed on a vibration- testing system which provided longitudinal excitation. A cylindrical container made with the acrylic plastic is used in the experiment. A permanent magnet is in the state of floating in a magnetic fluid. The disk-shaped and ring-shaped magnets are examined. The different interfacial phenomena from the usual longitudinal liquid sloshing are observed. It is found that the wave motion frequency of magnetic fluid with a disk-shaped magnet in the container subject to vertical vibration is exactly same that of the excitation. In the case of ring-shaped magnet, the first symmetrical mode of one-half subharmonic response is dominant at lower excitation frequencies. The magnetic fluid disintegration of the free surface was also observed by a high-speed video camera system.

Sudo, Seiichi; Wakuda, Hirofumi; Yano, Tetsuya [Department of Machine Intelligence and Systems Engineering, Akita Prefectural University, Yurihonjyo 015-0055 (Japan)

2008-02-21

346

Zero-order suppression for two-photon holographic excitation.  

PubMed

Wavefront shaping with liquid-crystal spatial light modulators (LC-SLMs) is frequently hindered by a remaining fraction of undiffracted light, the so-called "zero-order." This contribution is all the more detrimental in configurations for which the LC-SLM is Fourier conjugated to a sample by a lens, because in these cases this undiffracted light produces a diffraction-limited spot at the image focal plane. In this Letter we propose to minimize two-photon (2P) excitation of the sample, resulting from this unmodulated light, by introducing optical aberrations to the excitation beam. Aberrations are subsequently compensated by the LC-SLM, but only for the modulated part of the beam, and not for the zero-order component. In order to experimentally demonstrate the method, we use astigmatism as the optical aberration, by simply adding one or two cylindrical lenses in the optical path of the beam. A 104 decrease in zero-order-induced 2P fluorescence intensity is demonstrated. Combining this approach with temporal focusing is shown to decrease zero-order fluorescence by a factor of 4·106. PMID:25361128

Hernandez, Oscar; Guillon, Marc; Papagiakoumou, Eirini; Emiliani, Valentina

2014-10-15

347

Continuous wave-based multiphoton excitation fluorescence for capillary electrophoresis.  

PubMed

It was reported that a novel detection method, continuous wave (CW)-based multiphoton excitation (MPE) fluorescence detection with diode laser (DL), has been firstly proposed for capillary electrophoresis (CE). Special design of end-column detection configuration proved to be superior to on-column type, considering the detection sensitivity. Three different kinds of fluorescent tags that were widely used as molecular label in bio-analysis, such as small-molecule dye, fluorescent protein and nano particle or also referred to as quantum dot (QD), have been evaluated as samples for the constructed detection scheme. Quantitative analyses were also performed using rhodamine species as tests, which revealed dynamic linear range over two orders of magnitude, with detection limit down to zeptomole-level. Simultaneous detection of fluorescent dyestuffs with divergent excitation and emission wavelengths in a broad range showed advantage of this scheme over conventional laser-induced fluorescence (LIF) detection. Further investigations on CW-MPE fluorescence detection with diode laser for capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) separations of fluorescein isothiocyanate (FITC) labeled amino acids indicated good prospect of this detection approach in various micro or nano-column liquid phase separation technologies. PMID:16325835

Chen, Sheng; Liu, Bi-Feng; Fu, Ling; Xiong, Tao; Liu, Tiancai; Zhang, Zhihong; Huang, Zhen-Li; Lu, Qiang; Zhao, Yuan-Di; Luo, Qingming

2006-03-24

348

Liquid level detector  

DOEpatents

A liquid level detector for low pressure boilers. A boiler tank, from which vapor, such as steam, normally exits via a main vent, is provided with a vertical side tube connected to the tank at the desired low liquid level. When the liquid level falls to the level of the side tube vapor escapes therethrough causing heating of a temperature sensitive device located in the side tube, which, for example, may activate a liquid supply means for adding liquid to the boiler tank. High liquid level in the boiler tank blocks entry of vapor into the side tube, allowing the temperature sensitive device to cool, for example, to ambient temperature.

Grasso, A.P.

1984-02-21

349

Liquid level detector  

DOEpatents

A liquid level detector for low pressure boilers. A boiler tank, from which apor, such as steam, normally exits via a main vent, is provided with a vertical side tube connected to the tank at the desired low liquid level. When the liquid level falls to the level of the side tube vapor escapes therethrough causing heating of a temperature sensitive device located in the side tube, which, for example, may activate a liquid supply means for adding liquid to the boiler tank. High liquid level in the boiler tank blocks entry of vapor into the side tube, allowing the temperature sensitive device to cool, for example, to ambient temperature.

Grasso, Albert P. (Vernon, CT)

1986-01-01

350

Kinetics and Control of Liquid-Liquid Transition  

NASA Astrophysics Data System (ADS)

Recently it was revealed that even a single-component liquid can have more than two liquid states. The transition between these liquid states is called "liquid-liquid transition". This phenomenon has attracted a considerable attention because of its counter-intuitive character and the fundamental importance for our understanding of the liquid state of matter. The connection between the liquid-liquid transition and polyamorphism is also an interesting issue. In many cases, liquid-liquid transitions exist in a region which is difficult to access experimentally. Because of this experimental difficulty, the physical nature and kinetics of the transition remains elusive. However, a recent finding of liquid-liquid transition in molecular liquids opens up a possibility to study the kinetics in detail. Here we report the first detailed comparison between experiments and a phenomenological theory for the liquid-liquid transition of a molecular liquid, triphenyl phosphite. Both nucleation-growth-type and spinodal-decomposition-type liquid-liquid transformation are remarkably well reproduced by a two-order-parameter model of liquid that regards the liquid-liquid transition as the cooperative formation of locally favored structures. This may shed new light on the nature and the dynamics of the liquid-liquid transition. We also show evidence that this second order parameter controls the fragility of the liquid. We also discuss a possibility of controlling liquid-liquid transition by spatial confinement. Remaining open questions on the nature of the transition are also discussed.

Tanaka, Hajime; Kurita, Rei; Murata, Ken-ichiro

2008-02-01

351

Coulomb excitation of cadmium isotopes with protons  

Microsoft Academic Search

Low-lying positive parity levels of the isotopes in natural cadmium were Coulomb excited with 2.7-4.2 MeV protons. Eight levels of 111Cd up to 1130.4 keV and four levels of 113Cd up to 680.5 keV excitation energy, and the first 2+ states in even-even isotopes (110,112,114,116Cd) were excited. A 50 cm3 Ge(Li) detector was used to measure the deexcitation gamma-ray yields.

K. P. Singh; D. C. Tayal; Gulzar Singh; H. S. Hans

1985-01-01

352

Coulomb excitation of cadmium isotopes with protons  

Microsoft Academic Search

Low-lying positive parity levels of the isotopes in natural cadmium were Coulomb excited with 2.7--4.2 MeV protons. Eight levels of ¹¹¹Cd up to 1130.4 keV and four levels of ¹¹³Cd up to 680.5 keV excitation energy, and the first 2\\/sup +\\/ states in even-even isotopes (\\/sup 110,112,114,116\\/Cd) were excited. A 50 cm³ Ge(Li) detector was used to measure the deexcitation

K. P. Singh; D. C. Tayal; Gulzar Singh; H. S. Hans

1985-01-01

353

Collisional excitation of interstellar sulfur dioxide  

NASA Technical Reports Server (NTRS)

State-to-state rotational excitation rates for the asymmetric top molecule SO2 in collisions with low-energy He atoms have been computed. The intermolecular forces were obtained from an electron gas model, and collision dynamics were treated with the finite-order sudden approximation. The total excitation rate is probably accurate to better than 50 percent; however, individual state-to-state rates may be in error by factors of 2 or 3, and some smaller rates may be accurate only to an order of magnitude. Present results are expected to reflect within the same level of accuracy rates for excitation by collisions with H2 molecules.

Palma, Amedeo

1987-01-01

354

Liquid-liquid phase separation in biology.  

PubMed

Cells organize many of their biochemical reactions in non-membrane compartments. Recent evidence has shown that many of these compartments are liquids that form by phase separation from the cytoplasm. Here we discuss the basic physical concepts necessary to understand the consequences of liquid-like states for biological functions. PMID:25288112

Hyman, Anthony A; Weber, Christoph A; Jülicher, Frank

2014-10-11

355

Resonant excitation of plasma wakefield  

NASA Astrophysics Data System (ADS)

Particle accelerators are the main tool for discovering new elementary particles. Plasma based accelerator (PWFA) has been proven a very attractive new acceleration technique due to the large acceleration gradient it has reached (>50GV/m), which is two to three orders higher than the conventional radio frequency accelerators. PWFA is essentially an energy transformer transferring the energy from the drive bunches to witness bunches. For a future more compact and more affordable linear electron/positron collider, such an accelerator will require drive bunches with small longitudinal size (on the order of 100 um) and multi-kilojules of energy to access the new physics at the energy frontier. However, present relativistic electron bunch drivers carry less than 100Joules, thereby limiting the energy gain by the accelerated bunch to less than 100Joules. Proton bunches produced at CERN have been proven as potential drivers for PWFA due to the many tens of kilojules energy they carry (1e11 particles, 3.5-7TeV per particle). However, the CERN proton bunches are too long (approximately 12cm) to drive the wakefield efficiently. It has been proposed that a long particle bunch (protons, electrons, positrons, ... ) traveling in dense plasmas is subject to self-modulation instability (SMI), which transversely modulates a long bunch into multiple short bunches (on the scale of plasma wavelength) and therefore results in high acceleration amplitudes through resonant excitation. In this thesis, we demonstrate the first experimental evidence for the seeding of SMI with an electron bunch. We also use numerical simulations to study the SMI development with a higher-charge electron bunch and propose a possible experiment to demonstrate the transverse modulation directly in experiments. Moreover, we investigate with simulations the effect of transverse plasma radius on the SMI development, which is an important factor to consider when designing plasmas for future SMI and SMI-based experiments. Besides efficient drivers such as high-energy proton bunches, the PWFA also requires high transformer ratio (an indication of energy transfer efficiency) so that the witness bunch can gain energy efficiently from the drive bunch. In this thesis, we explore the possibility of reaching high transformer ratio in the weakly nonlinear PWFA regime so that the witness bunch particles can gain many times the energy of the drive bunch particles in a single acceleration stage.

Fang, Yun

356

An Excitation-Capacitor-Optimized Dual Stator-Winding Induction Generator With the Static Excitation Controller for Wind Power Application  

Microsoft Academic Search

This paper presents an optimal scheme of excitation capacitor to decrease the capacity of static excitation controller (SEC) for dual stator-winding induction generator (DWIG) system applied in wind power generation. The investigations into reactive excitation power released by the excitation capacitor and SEC il- lustrate that the optimal excitation capacitor is not only related to generator parameters, speed range, and

Feifei Bu; Wenxin Huang; Yuwen Hu; Kai Shi

2011-01-01

357

Thermal Excitations of Warped Membranes  

E-print Network

We explore thermal fluctuations of thin planar membranes with a frozen spatially-varying background metric and a shear modulus. We focus on a special class of $D$-dimensional ``warped membranes'' embedded in a $d-$dimensional space with $d\\ge D+1$ and a preferred height profile characterized by quenched random Gaussian variables $\\{h_\\alpha({\\bf q})\\}$, $\\alpha=D+1,\\ldots, d$, in Fourier space with zero mean and a power law variance $\\overline{ h_\\alpha({\\bf q}_1) h_\\beta({\\bf q}_2) } \\sim \\delta_{\\alpha, \\beta} \\, \\delta_{{\\bf q}_1, -{\\bf q}_2} \\, q_1^{-d_h}$. The case $D=2$, $d=3$ with $d_h = 4$ could be realized by flash polymerizing lyotropic smectic liquid crystals. For $D elastic constants are non-trivially renormalized and become scale dependent. Via a self consistent screening approximation we find that the renormalized bending rigidity increases for small wavevectors ${{\\bf q}}$ as $\\kappa_R \\sim q^{-\\eta_f}$, while the in-hyperplane elastic constants decrease according to $\\lambda_R,\\ \\mu_R \\sim q^{+\\eta_u}$. The quenched background metric is relevant (irelevant) for warped membranes characterized by exponent $d_h > 4 - \\eta_f^{(F)}$ ($d_h < 4 - \\eta_f^{(F)}$), where $\\eta_f^{(F)}$ is the scaling exponent for tethered surfaces with a flat background metric, and the scaling exponents are related through $\\eta_u + \\eta_f = d_h - D$ ($\\eta_u + 2 \\eta_f=4-D$).

Andrej Kosmrlj; David R. Nelson

2013-12-14

358

Students Excited by Stellar Discovery  

NASA Astrophysics Data System (ADS)

In the constellation of Ophiuchus, above the disk of our Milky Way Galaxy, there lurks a stellar corpse spinning 30 times per second -- an exotic star known as a radio pulsar. This object was unknown until it was discovered last week by three high school students. These students are part of the Pulsar Search Collaboratory (PSC) project, run by the National Radio Astronomy Observatory (NRAO) in Green Bank, WV, and West Virginia University (WVU). The pulsar, which may be a rare kind of neutron star called a recycled pulsar, was discovered independently by Virginia students Alexander Snider and Casey Thompson, on January 20, and a day later by Kentucky student Hannah Mabry. "Every day, I told myself, 'I have to find a pulsar. I better find a pulsar before this class ends,'" said Mabry. When she actually made the discovery, she could barely contain her excitement. "I started screaming and jumping up and down." Thompson was similarly expressive. "After three years of searching, I hadn't found a single thing," he said, "but when I did, I threw my hands up in the air and said, 'Yes!'." Snider said, "It actually feels really neat to be the first person to ever see something like that. It's an uplifting feeling." As part of the PSC, the students analyze real data from NRAO's Robert C. Byrd Green Bank Telescope (GBT) to find pulsars. The students' teachers -- Debra Edwards of Sherando High School, Leah Lorton of James River High School, and Jennifer Carter of Rowan County Senior High School -- all introduced the PSC in their classes, and interested students formed teams to continue the work. Even before the discovery, Mabry simply enjoyed the search. "It just feels like you're actually doing something," she said. "It's a good feeling." Once the pulsar candidate was reported to NRAO, Project Director Rachel Rosen took a look and agreed with the young scientists. A followup observing session was scheduled on the GBT. Snider and Mabry traveled to West Virginia to assist in the follow-up observations, and Thompson joined online. "Observing with the students is very exciting. It gives the students a chance to learn about radio telescopes and pulsar observing in a very hands-on way, and it is extra fun when we find a pulsar," said Rosen. Snider, on the other hand, said, "I got very, very nervous. I expected when I went there that I would just be watching other people do things, and then I actually go to sit down at the controls. I definitely didn't want to mess something up." Everything went well, and the observations confirmed that the students had found an exotic pulsar. "I learned more in the two hours in the control room than I would have in school the whole day," Mabry said. Pulsars are spinning neutron stars that sling lighthouse beams of radio waves or light around as they spin. A neutron star is what is left after a massive star explodes at the end of its normal life. With no nuclear fuel left to produce energy to offset the stellar remnant's weight, its material is compressed to extreme densities. The pressure squeezes together most of its protons and electrons to form neutrons; hence, the name neutron star. One tablespoon of material from a pulsar would weigh 10 million tons -- as much as a supertanker. The object that the students discovered is in a special class of pulsar that spins very fast - in this case, about 30 times per second, comparable to the speed of a kitchen blender. "The big question we need to answer first is whether this is a young pulsar or a recycled pulsar," said Maura McLaughlin, an astronomer at WVU. "A pulsar spinning that fast is very interesting as it could be newly born or it could be a very old, recycled pulsar." A recycled pulsar is one that was once in a binary system. Material from the companion star is deposited onto the pulsar, causing it to speed up, or be recycled. Mystery remains, however, about whether this pulsar has ever had a companion star. If it did, "it may be t

2011-02-01

359

Zero gravity liquid mixer  

NASA Technical Reports Server (NTRS)

An apparatus for mixing liquids under conditions of zero gravity is disclosed. The apparatus is comprised of a closed reservoir for the liquids, with a means for maintaining a positive pressure on the liquids in the reservoir. A valved liquid supply line is connected to the reservoir for supplying the reservoir with the liquids to be mixed in the reservoir. The portion of the reservoir containing the liquids to be mixed is in communication with a pump which alternately causes a portion of the liquids to flow out of the pump and into the reservoir to mix the liquids. The fluids in the reservoir are in communication through a conduit with the pump which alternately causes a portion of the fluids to flow out of the pump and into the sphere. The conduit connecting the pump and sphere may contain a nozzle or other jet-forming structure such as a venturi for further mixing the fluids.

Booth, F. W.; Bruce, R. A. (inventors)

1973-01-01

360

Liquid medication administration  

MedlinePLUS

... easily. Oral syringes have some advantages for giving liquid medications. They are accurate. They are easy to ... cups are also a handy way to give liquid medications. However, dosing errors have occurred with them. ...

361

Fear, excitement, and financial risk-taking.  

PubMed

Can fear trigger risk-taking? In this paper, we assess whether fear can be reinterpreted as a state of excitement as a result of contextual cues and promote, rather than discourage, risk-taking. In a laboratory experiment, the participants' emotional states were induced (fear vs. control), followed by a purportedly unrelated financial task. The task was framed as either a stock market investment or an exciting casino game. Our results showed that incidental fear (vs. control) induced risk-averse behaviour when the task was framed as a stock investment decision. However, fear encouraged risk-taking when the very same task was framed as an exciting casino game. The impact of fear on risk-taking was partially mediated by the excitement felt during the financial task. PMID:24661027

Lee, Chan Jean; Andrade, Eduardo B

2015-01-01

362

Acoustics of Excited Jets: A Historical Perspective  

NASA Technical Reports Server (NTRS)

The idea that a jet may be excited by external forcing is not new. The first published demonstration of a jet responding to external pressure waves occurred in the mid-1800's. It was not, however, until the 1950's, with the advent of commercial jet aircraft, that interest in the subject greatly increased. Researchers first used excited jets to study the structure of the jet and attempt to determine the nature of the noise sources. The jet actuators of the time limited the range (Reynolds and Mach numbers) of jets that could be excited. As the actuators improved, more realistic jets could be studied. This has led to a better understanding of how jet excitation may be used not only as a research tool to understand the flow properties and noise generation process, but also as a method to control jet noise.

Brown, Cliffard A.

2005-01-01

363

Mode Selective Excitation Using Coherent Control Spectroscopy  

SciTech Connect

Femtosecond time-resolved coherent anti-Stokes Raman scattering (fs-CARS) gives access to ultrafast molecular dynamics. However, femtosecond laser pulses are spectrally broad and therefore coherently excite several molecular modes. While the temporal resolution is high, usually no mode-selective excitation is possible. This paper demonstrates the feasibility of selectively exciting specific molecular vibrations in solution phase with shaped fs laser excitation using a feedback-controlled optimization technique guided by an evolutionary algorithm. This approach is also used to obtain molecule-specific CARS spectra from a mixture of different substances. The optimized phase structures of the fs pulses are characterized to get insight into the control process. Possible applications of the spectrum control are discussed.

Singh, Ajay K. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai-400094 (India); School of Engineering and Science, Jacobs University Bremen, Bremen, 28759 (Germany); Konradi, Jakow; Materny, Arnulf [School of Engineering and Science, Jacobs University Bremen, Bremen, 28759 (Germany); Sarkar, Sisir K. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai-400094 (India)

2008-11-14

364

PREFACE: 6th Liquid Matter Conference  

NASA Astrophysics Data System (ADS)

This special issue of Journal of Physics: Condensed Matter contains the Proceedings of the 6th Liquid Matter Conference held in Utrecht, The Netherlands, 2-6 July 2005. The three-yearly Liquid Matter Conference is organized by the Liquids Section of the Condensed Matter Division of the European Physical Society. This series of meetings began in Lyon in 1990. The most recent meeting was held in 2003 in Konstanz. The aim of the Liquid Matter Conferences is to bring together scientists working on the liquid state of matter. This rapidly growing field includes the physics, chemistry, biology and chemical engineering of liquid matter as well as various applied research areas. In fact, the Utrecht meeting had, for the first time, a special session devoted to Fundamental Challenges in Applied Liquid Physics and Microfluidics. The Utrecht meeting had 760 registered participants from four continents. An important event at this meeting was the award of the First Liquid Matter Prize of the European Physical Society to Professor Jean-Pierre Hansen FRS, of Cambridge University. In addition to a plenary speech by the recipient of the Liquid Matter Prize, the scientific programme consisted of 10 plenary lectures, 117 symposia talks, 25 of which were keynote lectures and some 650 poster contributions. The meeting also hosted a one-day symposium of the Division of Liquids and Interfaces of the Chemical Sciences division of NWO. This special issue of Journal of Physics: Condensed Matter contains 61 of the oral communications. Liquid state physics is at the interface of many fields of research. As a consequence, many of the attendants come from adjacent fields and find in the Liquid Matter Conference a forum to meet experts from other areas of research. This aspect of the Liquid Matter Conference makes it an exciting meeting as it not only offers the participants an up-to-date picture of the status of research into the liquid state of matter, but it also allows them to establish new (and often unexpected) trans-disciplinary contacts for joint scientific endeavours. This applies in particular to the area of soft condensed matter such as colloidal suspensions, polymeric systems and biological materials. The conference was held at the Uithof, the campus of the University of Utrecht. The organizers gratefully acknowledge the generosity of the University and City of Utrecht, which enabled us to stage both the scientific part of the conference and several festive and cultural events in some of the most attractive venues of the Netherlands. We were also delighted by the substantial contributions offered by the sponsors of the 6th Liquid Matter Conference. With this support it became possible to support a large number of scientists who would otherwise not have been able to attend. Finally, we owe a great debt of gratitude to the secretarial staff of the conference and the many students, postdocs and other colleagues who helped tirelessly (and very efficiently) to make the conference run smoothly. The Board of the Liquids Section of the European Physical Society decided that the 7th Liquid Matter Conference will be held in Lund (Sweden). The tentative dates are Friday 27 June 2008 to Tuesday 1 July 2008.

Dijkstra, Marjolein; van Roij, René; Vroege, Gert Jan; Lekkerkerker, Henk; Frenkel, Daan

2005-11-01

365

Fast pulsed excitation wiggler or undulator  

DOEpatents

A fast pulsed excitation, electromagnetic undulator or wiggler, employing geometrically alternating substacks of thin laminations of ferromagnetic material, together with a single turn current loop excitation of the composite assembly, of such shape and configuration that intense, spatially alternating, magnetic fields are generated; for use as a pulsed mode undulator or wiggler radiator, for use in a Free Electron Laser (FEL) type radiation source or, for use in an Inverse Free Electron Laser (IFEL) charged particle accelerator.

van Steenbergen, Arie (Shoreham, NY)

1990-01-01

366

Magnesium induces neuronal apoptosis by suppressing excitability  

Microsoft Academic Search

In clinical obstetrics, magnesium sulfate (MgSO4) use is widespread, but effects on brain development are unknown. Many agents that depress neuronal excitability increase developmental neuroapoptosis. In this study, we used dissociated cultures of rodent hippocampus to examine the effects of Mg++ on excitability and survival. Mg++-induced caspase-3-associated cell loss at clinically relevant concentrations. Whole-cell patch-clamp techniques measured Mg++ effects on

W H Dribben; L N Eisenman; S Mennerick

2010-01-01

367

Electron-impact vibrational excitation of tetrahydrofuran  

NASA Astrophysics Data System (ADS)

Low-energy differential and integral cross sections for the electron-impact vibrational excitation of tetrahydrofuran are presented. The data concern four features in the vibrational excitation electron energy-loss spectrum of tetrahydrofuran over the energy-loss range of 0-0.9 eV. The results show weak influence from long-range dipole interactions, being mainly isotropic. Comparison with earlier work is presented.

Khakoo, M. A.; Orton, D.; Hargreaves, L. R.; Meyer, N.

2013-07-01

368

Search for excited leptons at LEP  

Microsoft Academic Search

Excited leptons have been searched for using data recorded by the OPAL detector at LEP. No evidence for such particles has been found. From the study of e+e- --> l+l-gammagamma events, lower limits on the masses of spin-1\\/2 excited leptons are found to be 44.9 GeV at 95% confidence level. From the study of e+e- -->l+l-gamma events, upper limits on

M. Z. Akrawy; Gideon Alexander; J. Allison; P. P. Allport; K. J. Anderson; J. C. Armitage; Geoffrey T J Arnison; P. Ashton; Georges Azuelos; J. T. M. Baines; A. H. Ball; J. Banks; G. J. Barker; R. J. Barlow; J Richard Batley; J. Becker; T. Behnke; K. W. Bell; G. Bella; Siegfried Bethke; O. Biebel; U. Binder; Ian J Bloodworth; P. Bock; Horst Breuker; R. M. Brown; R. Brun; A. Buijs; Helfried J Burckhart; P. Capiluppi; R. K. Carnegie; A. A. Carter; J. R. Carter; C. Y. Chang; D. G. Charlton; J. T. M. Chrin; I. Cohen; W. J. Collins; J. E. Conboy; M. Couch; M. Coupland; M. Cuffiani; S. Dado; G. M. Dallavalle; P. Debu; M. M. Deninno; A. Dieckmann; Michael Dittmar; M. S. Dixit; E. Duchovni; I. P. Duerdoth; D J P Dumas; H. El Mamouni; P. A. Elcombe; P. G. Estabrooks; E. Etzion; Franco Luigi Fabbri; Philippe Farthouat; H. M. Fischer; D. G. Fong; M. T. French; C. Fukunaga; A. Gaidot; O. Ganel; J. W. Gary; J. Gascon; N. I. Geddes; C. N. P. Gee; C. Geich-Gimbel; S. W. Gensler; F. X. Gentit; G. Giacomelli; V. Gibson; W. R. Gibson; James D Gillies; J. Goldberg; M. J. Goodrick; W. Gorn; D. Granite; E. Gross; P. Grosse-Wiesmann; Jacob Grunhaus; H. Hagedorn; J. Hagemann; M. Hansroul; C. K. Hargrove; J. Hart; P. M. Hattersley; M. Hauschild; C. M. Hawkes; E. Heflin; Richard J Hemingway; R. D. Heuer; J. C. Hill; S. J. Hillier; C. Ho; J. D. Hobbs; P. R. Hobson; D. Hochman; B. Holl; R James Homer; S. R. Hou; C. P. Howarth; R. E. Hughes-Jones; P. Igo-Kemenes; H. Ihssen; D. C. Imrie; A. Jawahery; P. W. Jeffreys; H. Jeremie; Martin Paul Jimack; M. Jobes; R. W. L. Jones; P. Jovanovic; D A Karlen; K. Kawagoe; T. Kawamoto; R. G. Kellogg; B. W. Kennedy; C. Kleinwort; D. E. Klem; G. Knop; T. Kobayashi; T. P. Kokott; L. Köpke; R V Kowalewski; H. Kreutzmann; J. von Krogh; J. Kroll; M. Kuwano; P. Kyberd; G. D. Lafferty; F. Lamarche; W. J. Larson; J. G. Layter; P. Le Du; P. Leblanc; A. M. Lee; Daniel Lellouch; P. Lennert; L. Lessard; L. Levinson; S. L. Lloyd; F. K. Loebinger; J. M. Lorah; B. Lorazo; Michael J Losty; J. Ludwig; N. Lupu; J. Ma; A. A. MacBeth; M. Mannelli; S. Marcellini; G. Maringer; A. J. Martin; J. P. Martin; T. Mashimo; P. Mättig; U. Maur; T. J. McMahon; A. C. McPherson; F. Meijers; D. Menszner; F. S. Merritt; H. Mes; Aldo Michelini; R. P. Middleton; G. Mikenberg; D. J. Miller; C. Milstene; M. Minowa; W. Mohr; A. Montanari; T. Mori; M. W. Moss; P. G. Murphy; W. J. Murray; B. Nellen; H. H. Nguyen; M. Nozaki; A. J. P. O'Dowd; S. W. O'Neale; B. P. O'Neill; F. G. Oakham; F. Odorici; M. Ogg; H. Oh; M. J. Oreglia; S. Orito; J. P. Pansart; G. N. Patrick; S. J. Pawley; P. Pfister; J. E. Pilcher; James L Pinfold; D. E. Plane; B. Poli; A. Pouladdej; T. W. Pritchard; G. Quast; J. Raab; M. W. Redmond; D. L. Rees; M. Regimbald; K. Riles; C. M. Roach; S. A. Robins; A. Rollnik; J. M. Roney; S. Rossberg; A. M. Rossi; P. Routenburg; K. Runge; O. Runolfsson; S. Sanghera; R. A. Sansum; M. Sasaki; B. J. Saunders; A. D. Schaile; W. Schappert; P. Scharff-Hansen; H. von der Schmitt; S. Schreiber; J. Schwarz; A. Shapira; B. C. Shen; P. Sherwood; A. Simon; P. Singh; G. P. Siroli; A M Smith; A. M. Smith; T. J. Smith; G. A. Snow; E. J. Spreadbury; R. W. Springer; M. Sproston; K. Stephens; H. E. Stier; R. Ströhmer; D. Strom; H. Takeda; T. Takeshita; T. Tsukamoto; M. F. Turner; G. Tysarczyk-Niemeyer; D. van den Plas; G. J. Vandalen; G. Vasseur; C. J. Virtue; A. Wagner; C. Wahl; C. P. Ward; D. R. Ward; J. Waterhouse; P. M. Watkins; A. T. Watson; N. K. Watson; M. Weber; S. Weisz; N. Wermes; M. Weymann; G. W. Wilson; J. A. Wilson; I Wingerter-Seez; V.-H. Winterer; N. C. Wood; S A Wotton; B. Wuensch; T. R. Wyatt; R. Yaari; Y. Yang; G. Yekutieli; T. Yoshida; W. Zeuner; G. T. Zorn

1990-01-01

369

Critical fronts in initiation of excitation waves  

NASA Astrophysics Data System (ADS)

We consider the problem of initiation of propagating waves in a one-dimensional excitable fiber. In the FitzHugh-Nagumo theory, the key role is played by “critical nucleus” and “critical pulse” solutions whose (center-) stable manifold is the threshold surface separating initial conditions leading to propagation and those leading to decay. We present evidence that in cardiac excitation models, this role is played by “critical front” solutions.

Idris, I.; Biktashev, V. N.

2007-08-01

370

Intrinsic asymmetry of polar motion excitation  

NASA Astrophysics Data System (ADS)

Anisotropy of the pole tide and Earth triaxiality make the polar motion excitation asymmetric with respect to and y pole coordinates (Okamoto and Sasao 1977). After having proposed a general description of these non isotropic effects, we show that there are significant in light of the contemporaneous accuracy of the pole coordinates and cannot be cast aside in the interpretation of the Chandler wobble excitation

Bizouard, C.

2012-12-01

371

Localized and propagating excitations in gapped phases of spin systems with bond disorder  

NASA Astrophysics Data System (ADS)

Using the conventional T-matrix approach, we discuss gapped phases in one-, two-, and three-dimensional (3D) spin systems (both with and without a long-range magnetic order) with bond disorder and with weakly interacting bosonic elementary excitations. This work is motivated by recent experimental and theoretical activity in spin-liquid-like systems with disorder and in the disordered interacting boson problem. In particular, we apply our theory to both paramagnetic low-field and fully polarized high-field phases in dimerized spin-1/2 systems and in integer-spin magnets with large single-ion easy-plane anisotropy D with disorder in exchange coupling constants (and/or D). The elementary excitation spectrum and the density of states are calculated in the first order in defects concentration c ?1. In 2D and 3D systems, the scattering on defects leads to a finite damping of all propagating excitations in the band except for states lying near its edges. We demonstrate that the analytical approach is inapplicable for states near the band edges and our numerical calculations reveal their localized nature. We find that the damping of propagating excitations can be much more pronounced in considered systems than in magnetically ordered gapless magnets with impurities. In 1D systems, the disorder leads to localization of all states in the band, while those lying far from the band edges (short-wavelength excitations) can look like conventional wave packets.

Utesov, O. I.; Sizanov, A. V.; Syromyatnikov, A. V.

2014-10-01

372

Liquid detection circuit  

DOEpatents

Herein is a circuit which is capable of detecting the presence of liquids, especially cryogenic liquids, and whose sensor will not overheat in a vacuum. The circuit parameters, however, can be adjusted to work with any liquid over a wide range of temperatures.

Regan, Thomas O. (North Aurora, IL)

1987-01-01

373

High Performance Liquid Chromatography  

E-print Network

HPLC - 1 High Performance Liquid Chromatography HPLC MEASUREMENT OF POLYCYCLIC AROMATIC HYDROCARBONS IN CIGARETTE SMOKE Last updated: June 17, 2014 #12;HPLC - 2 High Performance Liquid Chromatography identify as many PAH as possible in cigarette smoke using high performance liquid chromatography (HPLC

Nizkorodov, Sergey

374

Surface structure of liquid metals and the effect of capillary waves: X-ray studies on liquid indium  

SciTech Connect

We report x-ray reflectivity (XR) and small-angle off-specular diffuse-scattering (DS) measurements from the surface of liquid indium close to its melting point of 156thinsp{degree}C. From the XR measurements we extract the surface structure factor convolved with fluctuations in the height of the liquid surface. We present a model to describe DS that takes into account the surface structure factor, thermally excited capillary waves, and the experimental resolution. The experimentally determined DS follows this model with no adjustable parameters, allowing the surface structure factor to be deconvolved from the thermally excited height fluctuations. The resulting local electron-density profile displays exponentially decaying surface-induced layering similar to that previously reported for Ga and Hg. We compare the details of the local electron-density profiles of liquid In, which is a nearly free-electron metal, and liquid Ga, which is considerably more covalent and shows directional bonding in the melt. The oscillatory density profiles have comparable amplitudes in both metals, but surface layering decays over a length scale of 3.5{plus_minus}0.6thinsp{Angstrom} for In and 5.5{plus_minus}0.4thinsp{Angstrom} for Ga. Upon controlled exposure to oxygen, no oxide monolayer is formed on the liquid In surface, unlike the passivating film formed on liquid gallium. {copyright} {ital 1999} {ital The American Physical Society}

Tostmann, H. [Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States)] [Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); DiMasi, E. [Department of Physics, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)] [Department of Physics, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Pershan, P.S. [Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States)] [Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Ocko, B.M. [Department of Physics, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)] [Department of Physics, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Shpyrko, O.G. [Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States)] [Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Deutsch, M. [Department of Physics, Bar-Ilan University, Ramat-Gan 52900 (Israel)] [Department of Physics, Bar-Ilan University, Ramat-Gan 52900 (Israel)

1999-01-01

375

Abstract Submitted for the MAR08 Meeting of  

E-print Network

D) ballistic conductor, which has Tomonaga-Luttinger liquid (TLL) state that arises from.14 (E) Observation of phase transition from Tomonaga- Luttinger liquid states to superconductive phase interaction leads to BCS-type superconductivity (SC) in 2D and 3D conductors. Thus, interplay of SC

Maruyama, Shigeo

376

Vibrationally Excited Molecular Hydrogen Near Herschel 36  

E-print Network

We present the first high resolution UV spectra toward Herschel 36, a Trapezium-like system of high-mass stars contained within the Lagoon Nebula (M8, NGC 6523). The spectra reveal extreme ro-vibrational excitation of molecular hydrogen in material at a single velocity or very small range of velocities, with this component presumably lying near the star system and undergoing fluorescent excitation. The overall H$_2$ excitation is similar to, but apparently larger than, that seen towards HD 37903 which previously showed the largest vibrationally excited H$_2$ column densities seen in UV absorption spectra. While the velocities of the highly excited H$_2$ lines are consistent within each observation, it appears that they underwent a $\\sim$60 km s$^{-1}$ redshift during the 3.6 years between observations. In neither case does the velocity of the highly excited material match the velocity of the bulk of the line-of-sight material which appears to mostly be in the foreground of M8. Recent work shows unusually exci...

Rachford, Brian L; Ross, Teresa L

2014-01-01

377

Excited state dynamics of phthalocyanine films  

SciTech Connect

Femtosecond pump-probe transient absorption measurements were performed for thermally evaporated polycrystalline vanadyl and lead phthalocyanine (VOPc and PbPc) films in order to obtain information about the excitation energy migration and relaxation. The films were shown to be composed of phase II and amorphous material. Fast excitation localization in phase II was concluded from measurement and analysis of the ground and excited state spectra. Comparison of the ground state, difference absorption, and luminescence spectra suggests a small oscillator strength of the electronic transition from the lowest excited state to the ground state. The influence of local heating on the transient spectra is discussed, and the possibility to obtain the excitation decay kinetics free from this influence is proposed. Exciton-exciton annihilation with a time dependent rate (proportional to t{sup -0.5}) is observed in both films. This is explained by one-dimensional diffusion-limited annihilation. Linear relaxation times are equal to 28{+-}6 and 42{+-}8 ps and approximate intermolecular excitation hopping times of 0.1 divide 0.4 and 0.02 divide 0.08 ps were determined for VOPc and PbPc, respectively. 22 refs., 8 figs., 1 tab.

Gulbians, V.; Valkunas, L. [Vilnius Inst. of Physics (Lithuania)] [Vilnius Inst. of Physics (Lithuania); Chachisvillis, M.; Sundstrom, V. [Lund Univ. (Sweden)] [Lund Univ. (Sweden)

1996-02-08

378

Spin-Liquid Condensate of Spinful Bosons  

NASA Astrophysics Data System (ADS)

We introduce the concept of a bosonic spin liquid condensate (SLC), where spinful bosons in a lattice form a zero-temperature spin disordered charge condensate that preserves the spin rotation symmetry, but breaks the U(1) symmetry due to a spinless order parameter with charge one. It has an energy gap to all the spin excitations. We show that such SLC states can be realized in a system of spin S ?2 bosons. In particular, we analyze the SLC phase diagram in the spin 2 case using a mean-field variational wave function method. We show there is a direct analogy between the SLC and the resonating-valence-bond state.

Lian, Biao; Zhang, Shoucheng

2014-08-01

379

Exciting threshold dependence of self-sustained spikes in excitable neurons  

NASA Astrophysics Data System (ADS)

The dependence of self-sustained spikes on the exciting threshold is investigated by two neuron models with an initial stimulus. We find that in the sub-excitable regime of neuron, the exciting threshold is the key factor for an initial stimulus to induce self-sustained spikes, which is robust to the network structures. Furthermore, we even observe self-sustained spikes in a one-dimensional chain, in contrast to previous results stating that an external pacing or a loop structure is the necessary condition to sustain spikes. While in the excitable regime of neuron, we also find the effect of the exciting threshold, i.e. that the lower exciting threshold will result in strong firing synchronization but the higher threshold will result in weak firing synchronization. These findings may be helpful in understanding the microscopic mechanism of epileptic seizures.

Wang, Jianxiong; Liu, Zonghua

2011-07-01

380

First singlet (n,pi*) excited state of hydrogen-bonded complexes between water and pyrimidine.  

PubMed

Hydrogen bonds from water to excited-state formaldehyde and from water to excited-state pyridine have been shown to display novel motifs to traditional hydrogen bonds involving ground states, with, in particular for H2O:pyridine, strong interactions involving the electron-rich pi cloud dominating the (n,pi) excited state. We investigate H2O:pyrimidine and various dihydrated species and reveal another motif, one in which the hydrogen bonding can dramatically alter the electronic structure of the excited state. Such effects are rare for ground-state interactions for which hydrogen bonding usually acts to merely perturb the electronic structure of the participating molecules. It arises as the (n,pi*) excitation of isolated pyrimidine is delocalized over both nitrogens but asymmetric hydrogen bonding causes it to localize on just the noninteracting atom. As a result, the excited-state hydrogen bond in H2O:pyrimidine is suprisingly very similar to the ground-state structure. These results lead to an improved understanding of the spectroscopy of pyrimidine in liquid water, and to the prediction that stable excited-state hydrogen bonds in H2O:pyrimidine should be observable, despite failure of experiments to actually do so. They also provide a simple model for the intricate control over primary charge separation in photosynthesis exerted by hydrogen bonding, and for solvent-induced electron localization in symmetric mixed-valence complexes. All conclusions are based on strong parallels found between the results of calculations performed using density-functional theory (DFT) and time-dependent DFT (TDDFT), complete-active-space self-consistent-field (CASSCF) with second-order perturbation-theory correction (CASPT2) theory, and equation-of-motion coupled cluster (EOM-CCSD) theory, calculations that are verified through detailed comparison of computed properties with experimental data for both the isolated molecules and the ground-state hydrogen bond. PMID:16833480

Cai, Zheng-Li; Reimers, Jeffrey R

2005-03-01

381

Hydrogen bonding in the electronic excited state.  

PubMed

Because of its fundamental importance in many branches of science, hydrogen bonding is a subject of intense contemporary research interest. The physical and chemical properties of hydrogen bonds in the ground state have been widely studied both experimentally and theoretically by chemists, physicists, and biologists. However, hydrogen bonding in the electronic excited state, which plays an important role in many photophysical processes and photochemical reactions, has scarcely been investigated. Upon electronic excitation of hydrogen-bonded systems by light, the hydrogen donor and acceptor molecules must reorganize in the electronic excited state because of the significant charge distribution difference between the different electronic states. The electronic excited-state hydrogen-bonding dynamics, which are predominantly determined by the vibrational motions of the hydrogen donor and acceptor groups, generally occur on ultrafast time scales of hundreds of femtoseconds. As a result, state-of-the-art femtosecond time-resolved vibrational spectroscopy is used to directly monitor the ultrafast dynamical behavior of hydrogen bonds in the electronic excited state. It is important to note that the excited-state hydrogen-bonding dynamics are coupled to the electronic excitation. Fortunately, the combination of femtosecond time-resolved spectroscopy and accurate quantum chemistry calculations of excited states resolves this issue in laser experiments. Through a comparison of the hydrogen-bonded complex to the separated hydrogen donor or acceptor in ground and electronic excited states, the excited-state hydrogen-bonding structure and dynamics have been obtained. Moreover, we have also demonstrated the importance of hydrogen bonding in many photophysical processes and photochemical reactions. In this Account, we review our recent advances in electronic excited-state hydrogen-bonding dynamics and the significant role of electronic excited-state hydrogen bonding on internal conversion (IC), electronic spectral shifts (ESS), photoinduced electron transfer (PET), fluorescence quenching (FQ), intramolecular charge transfer (ICT), and metal-to-ligand charge transfer (MLCT). The combination of various spectroscopic experiments with theoretical calculations has led to tremendous progress in excited-state hydrogen-bonding research. We first demonstrated that the intermolecular hydrogen bond in the electronic excited state is greatly strengthened for coumarin chromophores and weakened for thiocarbonyl chromophores. We have also clarified that the intermolecular hydrogen-bond strengthening and weakening correspond to red-shifts and blue-shifts, respectively, in the electronic spectra. Moreover, radiationless deactivations (via IC, PET, ICT, MLCT, and so on) can be dramatically influenced through the regulation of electronic states by hydrogen-bonding interactions. Consequently, the fluorescence of chromophores in hydrogen-bonded surroundings is quenched or enhanced by hydrogen bonds. Our research expands our understanding of the nature of hydrogen bonding by delineating the interaction between hydrogen bonds and photons, thereby providing a basis for excited-state hydrogen bonding studies in photophysics, photochemistry, and photobiology. PMID:22070387

Zhao, Guang-Jiu; Han, Ke-Li

2012-03-20

382

Radiation monitor for liquids  

DOEpatents

A radiation monitor for use with liquids that utilizes air ions created by alpha radiation emitted by the liquids as its detectable element. A signal plane, held at an electrical potential with respect to ground, collects these air ions. A guard plane or guard rings is used to limit leakage currents. In one embodiment, the monitor is used for monitoring liquids retained in a tank. Other embodiments monitor liquids flowing through a tank, and bodies of liquids, such as ponds, lakes, rivers and oceans.

Koster, James E. (Los Alamos, NM); Bolton, Richard D. (Los Alamos, NM)

1999-01-01

383

Radiation monitor for liquids  

DOEpatents

A radiation monitor for use with liquids that utilizes air ions created by alpha radiation emitted by the liquids as its detectable element. A signal plane, held at an electrical potential with respect to ground, collects these air ions. A guard plane or guard rings is used to limit leakage currents. In one embodiment, the monitor is used for monitoring liquids retained in a tank. Other embodiments monitor liquids flowing through a tank, and bodies of liquids, such as ponds, lakes, rivers and oceans. 4 figs.

Koster, J.E.; Bolton, R.D.

1999-03-02

384

Liquid Wall Chambers  

SciTech Connect

The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

Meier, W R

2011-02-24

385

Nanowire liquid pumps  

NASA Astrophysics Data System (ADS)

The ability to form tiny droplets of liquids and control their movements is important in printing or patterning, chemical reactions and biological assays. So far, such nanofluidic capabilities have principally used components such as channels, nozzles or tubes, where a solid encloses the transported liquid. Here, we show that liquids can flow along the outer surface of solid nanowires at a scale of attolitres per second and the process can be directly imaged with in situ transmission electron microscopy. Microscopy videos show that an ionic liquid can be pumped along tin dioxide, silicon or zinc oxide nanowires as a thin precursor film or as beads riding on the precursor film. Theoretical analysis suggests there is a critical film thickness of ~10 nm below which the liquid flows as a flat film and above which it flows as discrete beads. This critical thickness is the result of intermolecular forces between solid and liquid, which compete with liquid surface energy and Rayleigh-Plateau instability.

Huang, Jian Yu; Lo, Yu-Chieh; Niu, Jun Jie; Kushima, Akihiro; Qian, Xiaofeng; Zhong, Li; Mao, Scott X.; Li, Ju

2013-04-01

386

Liquid Propellant Manipulated Acoustically  

NASA Technical Reports Server (NTRS)

Fluids are difficult to manage in the space environment. Without gravity, the liquid and gas do not always remain separated as they do in the 1g environment of Earth. Instead the liquid and gas volumes mix and migrate under the influence of surface tension, thermodynamic forces, and external disturbances. As a result, liquid propellants may not be in a useable location or may even form a chaotic mix of liquid and gas bubbles. In the past, mechanical pumps, baffles, and a variety of specialized passive devices have been used to control the liquid and gas volumes. These methods need to be carefully tuned to a specific configuration to be effective. With increasing emphasis on long-term human activity in space there is a trend toward liquid systems that are more flexible and provide greater control. We are exploring new methods of manipulating liquids by using the nonlinear acoustic effects achieved by using beams of highly directed high-intensity acoustic waves.

Oeftering, Richard C.; Chato, David J.; Mann, Adin, III

2003-01-01

387

The Liquid Crystal Institute  

NSDL National Science Digital Library

The homepage of the Liquid Crystal Institute (LCI) presents gorgeous color images produced from liquid crystal, research overviews, technology invention abstracts, news and conference links, and more. LCI is part of a consortium, selected by the National Science Foundation, based at the Center for Advanced Liquid Crystalline Optical Materials (ALCOM) at Kent State University. The consortium includes Kent State University, Case Western Reserve University, and the University of Akron. ALCOM focuses on interdisciplinary research and development of liquid crystal optoelectronic materials, technology, and consumer products. A few of the liquid crystal studies featured here are fine structure and oily streak defects, magneto-optic response, text display applications, and organic synthesis. One of LCI's projects, the Polymers and Liquid Crystals Textbook, was featured in the December 13, 1996 Scout Report for Science & Engineering The LCI Website is not especially well-organized, but it contains lots of information about liquid crystal technology.

388

Liquid Metal Transformers  

E-print Network

The room temperature liquid metal is quickly emerging as an important functional material in a variety of areas like chip cooling, 3D printing or printed electronics etc. With diverse capabilities in electrical, thermal and flowing behaviors, such fluid owns many intriguing properties that had never been anticipated before. Here, we show a group of unconventional phenomena occurring on the liquid metal objects. Through applying electrical field on the liquid metals immersed in water, a series of complex transformation behaviors such as self-assembling of a sheet of liquid metal film into a single sphere, quick mergences of separate metal droplets, controlled self-rotation and planar locomotion of liquid metal objects can be realized. Meanwhile, it was also found that two accompanying water vortexes were induced and reliably swirled near the rotating liquid metal sphere. Further, effects of the shape, size, voltage, orientation and geometries of the electrodes to control the liquid metal transformers were clar...

Sheng, Lei; Liu, Jing

2014-01-01

389

Liquid/Gas Vortex Separator  

NASA Technical Reports Server (NTRS)

Liquid/gas separator vents gas from tank of liquid that contains gas randomly distributed in bubbles. Centrifugal force separates liquid and gas, forcing liquid out of vortex tube through venturi tube. Gas vented through exhaust port. When liquid detected in vent tube, exhaust port closed, and liquid/gas mixture in vent tube drawn back into tank through venturi.

Morris, B. G.

1986-01-01

390

Ultrasonic depth gauge for liquids under high pressure  

NASA Technical Reports Server (NTRS)

The invention relates to an ultrasonic depth gauge for liquids under high pressure and is particularly useful in the space industry where it is necessary to use a pressurized gas to transfer a liquid from one location to another. Conventional liquid depth gauges do not have the capability to operate under extreme high pressure (i.e., exceeding 300 psi). An ultrasonic depth gauge capable of withstanding high pressure according to the present invention is comprised of a transducer assembly and a supporting electronics unit. The former is mounted in to the bottom wall of a storage vessel with its resonating surface directly exposed to the highly pressurized liquid in the vessel. In operation, the ultrasonic pulse propagates upward through the liquid to the liquid-gas interface in the storage vessel. When the ultrasonic echo returns from the liquid-gas interface, it re-excites the composite resonator into vibration. The supporting electronics unit measures the round-trip transmit time for the ultrasonic pulse and its return echo to traverse the depth of the highly pressurized liquid. The novelty of the invention resides in the use of a conventional transducer rigidly bonded to the inside wall of a bored out conventional high-pressure plug to form a composite resonator capable of withstanding extremely high pressure.

Zuckerwar, Allan J. (inventor); Mazel, David S. (inventor)

1988-01-01

391

Intensification of Liquid-Liquid Contacting Processes  

E-print Network

different energy sources and were investigated in this dissertation. They include electrostatic liquid spraying based on electric field and a two-disc spinning disc reactor based on high gravity field. Interfacial turbulence plays an important role...

Qiu, Zheyan

2010-09-01

392

Electronic excitations in long polyenes revisited.  

PubMed

We apply the valence shell model OM2 [W. Weber and W. Thiel, Theor. Chem. Acc. 103, 495, (2000)] combined with multireference configuration interaction (MRCI) to compute the vertical excitation energies and transition dipole moments of the low-energy singlet excitations in the polyenes with 4 ? N ? 22?-electrons. We find that the OM2/MRCI descriptions closely resemble those of Pariser-Parr-Pople (PPP) ?-electron models [P. Tavan and K. Schulten, Phys. Rev. B 36, 4337, (1987)], if equivalent MRCI procedures and regularly alternating model geometries are used. OM2/MRCI optimized geometries are shown to entail improved descriptions particularly for smaller polyenes (N ? 12), for which sizeable deviations from the regular model geometries are found. With configuration interaction active spaces covering also the ?- in addition to the ?-electrons, OM2/MRCI excitation energies turn out to become smaller by at most 0.35 eV for the ionic and 0.15 eV for the covalent excitations. The particle-hole (ph) symmetry, which in Pariser-Parr-Pople models arises from the zero-differential overlap approximation, is demonstrated to be only weakly broken in OM2 such that the oscillator strengths of the covalent 1B(u)(-) states, which artificially vanish in ph-symmetric models, are predicted to be very small. According to OM2/MRCI and experimental data the 1B(u)(-) state is the third excited singlet state for N < 12 and becomes the second for N ? 14. By comparisons with results of other theoretical approaches and experimental evidence we argue that deficiencies of the particular MRCI method employed by us, which show up in a poor size consistency of the covalent excitations for N > 12, are caused by its restriction to at most doubly excited references. PMID:22462859

Schmidt, Maximilian; Tavan, Paul

2012-03-28

393

Electronic excitations in long polyenes revisited  

NASA Astrophysics Data System (ADS)

We apply the valence shell model OM2 [W. Weber and W. Thiel, Theor. Chem. Acc. 103, 495, (2000)] combined with multireference configuration interaction (MRCI) to compute the vertical excitation energies and transition dipole moments of the low-energy singlet excitations in the polyenes with 4 <= N <= 22?-electrons. We find that the OM2/MRCI descriptions closely resemble those of Pariser-Parr-Pople (PPP) ?-electron models [P. Tavan and K. Schulten, Phys. Rev. B 36, 4337, (1987)], if equivalent MRCI procedures and regularly alternating model geometries are used. OM2/MRCI optimized geometries are shown to entail improved descriptions particularly for smaller polyenes (N <= 12), for which sizeable deviations from the regular model geometries are found. With configuration interaction active spaces covering also the ?- in addition to the ?-electrons, OM2/MRCI excitation energies turn out to become smaller by at most 0.35 eV for the ionic and 0.15 eV for the covalent excitations. The particle-hole (ph) symmetry, which in Pariser-Parr-Pople models arises from the zero-differential overlap approximation, is demonstrated to be only weakly broken in OM2 such that the oscillator strengths of the covalent 1Bu- states, which artificially vanish in ph-symmetric models, are predicted to be very small. According to OM2/MRCI and experimental data the 1Bu- state is the third excited singlet state for N < 12 and becomes the second for N >= 14. By comparisons with results of other theoretical approaches and experimental evidence we argue that deficiencies of the particular MRCI method employed by us, which show up in a poor size consistency of the covalent excitations for N > 12, are caused by its restriction to at most doubly excited references.

Schmidt, Maximilian; Tavan, Paul

2012-03-01

394

Van der Waals interaction of excited media  

E-print Network

Casimir interaction between two media of ground-state atoms is well described with the help of Lifshitz formula depending upon permittivity of media. We will show that this formula is in contradiction with experimental evidence for excited atoms. We calculate Casimir force between two atoms if one of them or both atoms are excited. We use methods of quantum electrodynamics specially derived for the problem. It enables us to take into account excited-state radiation widths of atoms. Then we calculate the force between excited atom and medium of ground-state atoms. The results are in agreement with the ones, obtained by other authors using perturbation theory or linear response theory. Generalization of our results to the case of interaction between two media of excited atoms results in a formula, which is in not only in quantitative, but in qualitative contradiction with Lifshits formula. This contradiction disappears if media of ground-state atoms are taken. Moreover, our result does not include permittivity of the media. It includes the quantity which differs from the permittivity only for excited atoms. The main features of our results are as follows. The interaction is resonant; the force may be either attractive or repulsive depending on resonant frequencies of the atoms of different media; the value of Casimir force may be several orders of magnitude lager than that predicted by Lifshitz formula. The features mentioned here are in agreement with known experimental and theoretical evidences obtained by many authors for interaction of a single excited atom with dielectric media.

Yury B. Sherkunov

2005-03-05

395

Fluctuation-induced Non-equilibrium Transition in a Liquid-Crystal Metastable System  

E-print Network

The research herein studies the Langevin dynamics allowing for an exchange of energy between liquid crystals and the thermal environment. This dynamics leads to fluctuation and dissipation behaviors in the motions of liquid crystals, and therefore drives the system toward non-equilibrium evolutional processes. In particular, for the operations of liquid-crystal metastable systems, the fluctuation could allow an excitation (non-equilibrium) transition against energy barriers to the globally-stable state. Implemented with an actual case of liquid crystal pi configuration, this work statistically studies the non-equilibrium metastable transitions and shows the dependence of the transition-time on the correlations (of fluctuations).

I. L. Ho

2010-11-14

396

Seismic response of liquid-filled tank with baffles  

NASA Astrophysics Data System (ADS)

In thispaper, the effects of a rigid baffle on the seismic response of liquid in a rigid cylindrical tank are evaluated. A baffle is an annular plate which supplies a kind of passive control on the effects of ground excitation. The contained liquid is assumed incompressible, inviscid and has irrotational motion. To estimate the seismic response, the method of superposition of modes has been applied. To analyze the rigid tank response, Laplace's equation is considered as the governing equation of the fluid domain, in both time and frequency domains. The boundary element method (BEM) is employed to evaluate the natural modes of liquid in a cylindrical tank. To gain this goal, the fluid domain is divided into two upper and lower parts partitioned by the baffle. Linearized kinematic and dynamic boundary conditions of the free surface of the contained liquid have been considered.

Shekari, Mohammad Reza

2014-09-01

397

Liquid-crystalline nanoparticles: Hybrid design and mesophase structures  

PubMed Central

Summary Liquid-crystalline nanoparticles represent an exciting class of new materials for a variety of potential applications. By combining supramolecular ordering with the fluid properties of the liquid-crystalline state, these materials offer the possibility to organise nanoparticles into addressable 2-D and 3-D arrangements exhibiting high processability and self-healing properties. Herein, we review the developments in the field of discrete thermotropic liquid-crystalline nanoparticle hybrids, with special emphasis on the relationship between the nanoparticle morphology and the nature of the organic ligand coating and their resulting phase behaviour. Mechanisms proposed to explain the supramolecular organisation of the mesogens within the liquid-crystalline phases are discussed. PMID:22509204

Greget, Romain; Dominguez, Cristina; Nagy, Zsuzsanna T; Guillon, Daniel; Gallani, Jean-Louis

2012-01-01

398

Local Energy Landscape in a Simple Liquid  

E-print Network

It is difficult to relate the properties of liquids and glasses directly to their structure because of complexity in the structure which defies precise definition. The potential energy landscape (PEL) approach is a very insightful way to conceptualize the structure-property relationship in liquids and glasses, particularly on the effect of temperature and history. However, because of the highly multi-dimensional nature of the PEL it is hard to determine, or even visualize, the actual details of the energy landscape. In this article we introduce a modified concept of the local energy landscape (LEL) which is limited in phase space, and demonstrate its usefulness using molecular dynamics simulation on a simple liquid at high temperatures. The local energy landscape is given as a function of the local coordination number, the number of the nearest neighbor atoms. The excitations in the LEL corresponds to the so-called beta-relaxation process. The LEL offers a simple but useful starting point to discuss complex phenomena in liquids and glasses.

Takuya Iwashita; Takeshi Egami

2014-10-31

399

Comparison of vapor formation of water at the solid/water interface to colloidal solutions using optically excited gold nanostructures.  

PubMed

The phase transformation properties of liquid water to vapor is characterized by optical excitation of the lithographically fabricated single gold nanowrenches and contrasted to the phase transformation properties of gold nanoparticles located and optically excited in a bulk solution system [two and three dimensions]. The 532 nm continuous wave excitation of a single gold nanowrench results in superheating of the water to the spinodal decomposition temperature of 580 ± 20 K with bubble formation below the spinodal decomposition temperature being a rare event. Between the spinodal decomposition temperature and the boiling point liquid water is trapped into a metastable state because a barrier to vapor nucleation exists that must be overcome before the thermodynamically stable state is realized. The phase transformation for an optically heated single gold nanowrench is different from the phase transformation of optically excited colloidal gold nanoparticles solution where collective heating effects dominates and leads to the boiling of the solution exactly at the boiling point. In the solution case, the optically excited ensemble of nanoparticles collectively raises the ambient temperature of water to the boiling point where liquid is converted into vapor. The striking difference in the boiling properties of the single gold nanowrench and the nanoparticle solution system can be explained in terms of the vapor-nucleation mechanism, the volume of the overheated liquid, and the collective heating effect. The interpretation of the observed regimes of heating and vaporization is consistent with our theoretical modeling. In particular, we explain with our theory why the boiling with the collective heating in a solution requires 3 orders of magnitude less intensity compared to the case of optically driven single nanowrench. PMID:24476426

Baral, Susil; Green, Andrew J; Livshits, Maksim Y; Govorov, Alexander O; Richardson, Hugh H

2014-02-25

400

Fluorescence Spectrum and Decay Measurement for Hsil VS Normal Cytology Differentiation in Liquid Pap Smear Supernatant  

NASA Astrophysics Data System (ADS)

Cervical smear material contains endo and exocervical cells, mucus and inflammative, immune cells in cases of pathology. Just not destroyed keratinocytes lay on the glass for microscopy. Liquid cytology supernatant apart other diagnostics could be used for photodiagnostic. The spectroscopic parameters suitable for Normal and HSIL cytology groups supernatant differentiation are demonstrated. The dried liquid PAP supernatant fractions—sediment and liquid were investigated. Excitation and emission matrices (EEM), supernatant fluorescence decay measured under 280 nm diode short pulse excitation and fluorescence spectroscopy by excitation with 355 nm laser light were analyzed. The differences between Normal and HSIL groups were statistically proven in the certain spectral regions. Fluorescence decay peculiarities show spectral regions consisting of few fluorophores. Obtained results on fluorescence differences in Normal and HSIL groups' supernatant shows the potency of photodiagnosis application in cervical screening.

Vaitkuviene, A.; Gegzna, V.; Juodkazis, S.; Jursenas, S.; Miasojedovas, S.; Kurtinaitiene, R.; Rimiene, J.; Vaitkus, J.

2009-06-01

401

Vibrationally Excited Molecular Hydrogen Near Herschel 36  

NASA Astrophysics Data System (ADS)

We present the first high resolution UV spectra toward Herschel 36, a Trapezium-like system of high-mass stars contained within the Lagoon Nebula (M8, NGC 6523). The spectra reveal extreme ro-vibrational excitation of molecular hydrogen in material at a single velocity or very small range of velocities, most likely the largest ever seen in UV absorption spectra. While the velocities of the highly excited H2 lines are consistent within each observation, it appears that they underwent a ?60 km s-1 redshift during the 3.6 years between observations. In neither case does the velocity of the highly excited material match the velocity of the bulk of the line-of-sight material which appears to mostly be in the foreground of M8. Recent work shows unusually excited CH and CH+ lines and several unusually broad Diffuse Interstellar Bands (DIBs) towards Herschel 36. Along with the H2 excitation, all of these findings appear to be related to the extreme environment within ˜0.1 pc of the massive young stellar system.

Rachford, Brian L.; Snow, T. P.; Ross, T.

2014-01-01

402

Targeting individual excited states in DMRG.  

NASA Astrophysics Data System (ADS)

The low-lying excited states of ?-conjugated molecules are important for the development of novel devices such as lasers, light-emitting diodes, photovoltaic cells, and field-effect transistors [1,2]. The ab-intio Density Matrix Renormalization Group (DMRG) provides a powerful way to explore the electronic structure of quasi-one-dimensional systems such as conjugated organic oligomers. However, DMRG is limited to targeting only low-lying excited states through state-averaged DMRG (SDMRG). There are several drawbacks; state-averaging degrades the accuracy of the excited states and is limited to at most a few of the low-lying states [3]. In this study, we present a new method for targeting higher individual excited states. Due to progress in the field of numerical analysis presented by Van Der Horst and others [4], we are able to target individual excited states of the Hamiltonian. This is accomplished by modifying the Jacobi-Davidson algorithm via a ``Harmonic Ritz'' procedure. We will present studies of oligoacenes and polyenes that compare the accuracy of SDMRG and Harmonic Davidson DMRG. [1] Burroughes, et al. , Nature 347, 539 (1990). [2] Shirota, J. Mater. Chem. 10, 1, (2000). [3] Ramasesha, Pati, Krishnamurthy, Shuai, Bredas, Phys. Rev. B. 54, 7598, (1997). [4] Bai, Demmel, Dongarra, Ruhe, Van Der Horst, Templates for the Solution of Algebraic Eigenvalue Problems, SIAM, 2000.

Dorando, Jonathan; Hachmann, Johannes; Kin-Lic Chan, Garnet

2007-03-01

403

Tone-excited jet: Theory and experiments  

NASA Technical Reports Server (NTRS)

A detailed study to understand the phenomenon of broadband jet-noise amplification produced by upstream discrete-tone sound excitation has been carried out. This has been achieved by simultaneous acquisition of the acoustic, mean velocity, turbulence intensities, and instability-wave pressure data. A 5.08 cm diameter jet has been tested for this purpose under static and also flight-simulation conditions. An open-jet wind tunnel has been used to simulate the flight effects. Limited data on heated jets have also been obtained. To improve the physical understanding of the flow modifications brought about by the upstream discrete-tone excitation, ensemble-averaged schlieren photographs of the jets have also been taken. Parallel to the experimental study, a mathematical model of the processes that lead to broadband-noise amplification by upstream tones has been developed. Excitation of large-scale turbulence by upstream tones is first calculated. A model to predict the changes in small-scale turbulence is then developed. By numerically integrating the resultant set of equations, the enhanced small-scale turbulence distribution in a jet under various excitation conditions is obtained. The resulting changes in small-scale turbulence have been attributed to broadband amplification of jet noise. Excellent agreement has been found between the theory and the experiments. It has also shown that the relative velocity effects are the same for the excited and the unexcited jets.

Ahuja, K. K.; Lepicovsky, J.; Tam, C. K. W.; Morris, P. J.; Burrin, R. H.

1982-01-01

404

Continuous transitions between composite Fermi liquid and Landau Fermi liquid: A route to fractionalized Mott insulators  

NASA Astrophysics Data System (ADS)

One of the most successful theories of a non-Fermi-liquid metallic state is the composite Fermi-liquid (CFL) theory of the half-filled Landau level. In this paper, we study continuous quantum phase transitions out of the CFL state and into a Landau Fermi liquid, in the limit of no disorder and fixed particle number. This transition can be induced by tuning the bandwidth of the Landau level relative to the interaction energy, for instance through an externally applied periodic potential. We find a transition to the Landau Fermi liquid through a gapless Mott insulator with a Fermi surface of neutral fermionic excitations. In the presence of spatial symmetries, we also find a direct continuous transition between the CFL and the Landau Fermi liquid. The transitions have a number of characteristic observable signatures, including the presence of two crossover temperature scales, resistivity jumps, and vanishing compressibility. When the composite fermions are paired instead, our results imply quantum critical points between various non-Abelian topological states, including the ?=1/2 Moore-Read Pfaffian [Ising × U(1) topological order], a version of the Kitaev B phase (Ising topological order), and paired electronic superconductors. To study such transitions, we use a projective construction of the CFL, which goes beyond the conventional framework of flux attachment to include a broader set of quantum fluctuations. These considerations suggest a possible route to fractionalized Mott insulators by starting with fractional quantum Hall states and tuning the Landau-level bandwidth.

Barkeshli, Maissam; McGreevy, John

2012-08-01

405

Patterns of conductivity in excitable automata with updatable intervals of excitations  

NASA Astrophysics Data System (ADS)

We define a cellular automaton where a resting cell excites if number of its excited neighbors belong to some specified interval and boundaries of the interval change depending on ratio of excited and refractory neighbors in the cell's neighborhood. We calculate excitability of a cell as a number of possible neighborhood configurations that excite the resting cell. We call cells with maximal values of excitability conductive. In exhaustive search of functions of excitation interval updates we select functions which lead to formation of connected configurations of conductive cells. The functions discovered are used to design conductive, wirelike, pathways in initially nonconductive arrays of cells. We demonstrate that by positioning seeds of growing conductive pathways it is possible to implement a wide range of routing operations, including reflection of wires, stopping wires, formation of conductive bridges, and generation of new wires in the result of collision. The findings presented may be applied in designing conductive circuits in excitable nonlinear media, reaction-diffusion chemical systems, neural tissue, and assemblies of conductive polymers.

Adamatzky, Andrew

2012-11-01

406

Coordination of under excitation limiters and loss of excitation relays with generator capability  

Microsoft Academic Search

This paper presents a brief review of the coordination issues between under excitation limiters (UELs), loss of excitation relays (LOEs) and generator capability. The generator's capability limitations in the leading power factor region are discussed. Present industry practice and some common alternatives of LOE settings are reviewed. The settings of the UEL are reviewed in this context.

G. Roger Bérubé; Les M. Hajagos

2009-01-01

407

A microscopic theory of photonucleation: Density functional approach for the properties of a fluid of two-level atoms, a part of which is excited  

E-print Network

We use the density functional method to examine the properties of the nonuniform (two-phase) fluid of two-level atoms, a part of which is excited. Basing on the analysis of the equation of state of a gas of two-level atoms, a part of which is excited, we suggest a simple density functional of the grand thermodynamical potential. We use the proposed density functional of the grand thermodynamical potential to calculate the nucleation barrier for vapor-to-liquid phase transition in the presence of excited atoms.

Oleg Derzhko; Vasyl Myhal

2006-10-05

408

Method for beam steering compensation in an ultra-high power liquid laser  

DOEpatents

Thermally induced distortion of the optical wavefront caused by heating of the laser media by waste heat from the excitation process and absorption of laser radiation creates optical phase errors. A system generates an error signal derived from the optical phase errors. The error signal is fed back to the power supplies driving semiconductor diodes that excite the lasing liquid thereby introducing an electrically controllable wedge into the optical cavity to correct the optical phase errors.

Ault, Earl R. (Livermore, CA)

2002-01-01

409

Two photon excited fluorescence from diamond nanoparticles  

NASA Astrophysics Data System (ADS)

The possibility of two photon eaxcited fluorescence by diamond nanoparticles is an interesting nonlinear phenomenon. We have grown 20-100 nm diamond nanoparticles by using chemical vapor deposition (CVD) and characterized their properties by using complementary techniques of AFM, SEM, and Raman spectroscopy.footnotetextR. Chakraborty, S. C. Sharma, and J. K. LaRoque, J. Nano Research, 12, 1123 (2010)^,footnotetextR. Chakraborty and S. C. Sharma, Physica B, 406, 4170 (2011) In this work, we have utilized femtosecond laser based two-photon excitation to study the emission of visible light (˜ 530 nm) as functions of the excitation wavelength (750-850 nm), excitation power, and size of the NPs. These results and their potential applications will be discussed.

Singh, Ankit; Ajaeroh, Mathias; Mohanty, Samar; Sharma, Suresh

2012-10-01

410

"Safe" Coulomb excitation of 30Mg.  

PubMed

We report on the first radioactive beam experiment performed at the recently commissioned REX-ISOLDE facility at CERN in conjunction with the highly efficient gamma spectrometer MINIBALL. Using 30Mg ions accelerated to an energy of 2.25 MeV/u together with a thin (nat)Ni target, Coulomb excitation of the first excited 2+ states of the projectile and target nuclei well below the Coulomb barrier was observed. From the measured relative deexcitation gamma-ray yields the B(E2;0(+)gs-->2(+)1) value of 30Mg was determined to be 241(31)e2 fm4. Our result is lower than values obtained at projectile fragmentation facilities using the intermediate-energy Coulomb excitation method, and confirms the theoretical conjecture that the neutron-rich magnesium isotope 30Mg resides outside the "island of inversion." PMID:15904283

Niedermaier, O; Scheit, H; Bildstein, V; Boie, H; Fitting, J; von Hahn, R; Köck, F; Lauer, M; Pal, U K; Podlech, H; Repnow, R; Schwalm, D; Alvarez, C; Ames, F; Bollen, G; Emhofer, S; Habs, D; Kester, O; Lutter, R; Rudolph, K; Pasini, M; Thirolf, P G; Wolf, B H; Eberth, J; Gersch, G; Hess, H; Reiter, P; Thelen, O; Warr, N; Weisshaar, D; Aksouh, F; Van den Bergh, P; Van Duppen, P; Huyse, M; Ivanov, O; Mayet, P; Van de Walle, J; Aystö, J; Butler, P A; Cederkäll, J; Delahaye, P; Fynbo, H O U; Fraile, L M; Forstner, O; Franchoo, S; Köster, U; Nilsson, T; Oinonen, M; Sieber, T; Wenander, F; Pantea, M; Richter, A; Schrieder, G; Simon, H; Behrens, T; Gernhäuser, R; Kröll, T; Krücken, R; Münch, M; Davinson, T; Gerl, J; Huber, G; Hurst, A; Iwanicki, J; Jonson, B; Lieb, P; Liljeby, L; Schempp, A; Scherillo, A; Schmidt, P; Walter, G

2005-05-01

411

NMR solvent peak suppression by nonlinear excitation  

NASA Astrophysics Data System (ADS)

Most existing NMR solvent peak suppression sequences provide a satisfactory dependence of the intensity of excited signals on frequency but poor phase characteristics. In practice this leads to spectral distortions which generally become more severe as the frequency selectivity of the sequence is increased. However, it is shown that by working well outside the linear response regime, excitation schemes which combine high frequency selectivity with good phase properties may be devised. Sequences of six rectangular radio-frequency pulses were discovered using a combination of coherent averaging theory to treat the near-resonant behavior and numerical simulation further from resonance. Extensive use of symmetry greatly simplifies both the coherent averaging calculations and the numerical simulations. The new pulse sequences have been given the acronym NERO (nonlinear excitation rejecting on-resonance). Experimental spectra of an enzyme in dilute aqueous solution are shown.

Levitt, Malcolm H.

1988-03-01

412

'Safe' Coulomb Excitation of {sup 30}Mg  

SciTech Connect

We report on the first radioactive beam experiment performed at the recently commissioned REX-ISOLDE facility at CERN in conjunction with the highly efficient {gamma} spectrometer MINIBALL. Using {sup 30}Mg ions accelerated to an energy of 2.25 MeV/u together with a thin {sup nat}Ni target, Coulomb excitation of the first excited 2{sup +} states of the projectile and target nuclei well below the Coulomb barrier was observed. From the measured relative deexcitation {gamma}-ray yields the B(E2;0{sub gs}{sup +}{yields}2{sub 1}{sup +}) value of {sup 30}Mg was determined to be 241(31)e{sup 2} fm{sup 4}. Our result is lower than values obtained at projectile fragmentation facilities using the intermediate-energy Coulomb excitation method, and confirms the theoretical conjecture that the neutron-rich magnesium isotope {sup 30}Mg resides outside the 'island of inversion'.

Niedermaier, O.; Scheit, H.; Bildstein, V.; Boie, H.; Fitting, J.; Hahn, R. von; Koeck, F.; Lauer, M.; Pal, U.K.; Podlech, H.; Repnow, R.; Schwalm, D. [Max-Planck-Insitut fuer Kernphysik, Heidelberg (Germany); Alvarez, C.; Ames, F.; Bollen, G.; Emhofer, S.; Habs, D.; Kester, O.; Lutter, R.; Rudolph, K. [Ludwig-Maximilians-Universitaet, Munich (Germany)] [and others

2005-05-06

413

Excited states in electronic structure calculations  

NASA Astrophysics Data System (ADS)

A first-principles quasiparticle approach to the electronic excitation energies in crystals and at surfaces is described. The quasiparticle energies are calculated within the GW approximation for comparison with photoemission and other spectroscopic experiments. Applications of the method to bulk semiconductors and the Si(111)2x1, Ge(111)2x1, and H/Si(111) surfaces are presented. In both cases, significant self-energy corrections arising from many-electron effects to the excitation energies are found. Using atomic positions from total energy minimization, the calculated excitation energies explain quantitatively the experimental spectra. This approach provides an ab initio means for analyzing and predicting results from spectroscopic probes.

Louie, S. G.

1992-07-01

414

Drift-induced excitable localized states.  

PubMed

Excitable localized states, spatial structures which possess both the features of temporal excitable pulses and of transverse cavity solitons, have been theoretically predicted in model systems as single pulses of light localized in space with a finite and deterministic duration. We study experimentally the nucleation of laser localized structures on a device defect and its motion along a spatial gradient. We demonstrate that in the reference frame of the drifting localized structure, the resulting dynamics presents the typical features of excitable systems. In particular, for specific parameter values, we observe that the nucleation of laser localized structures is triggered by noise, while the drift of the localized structure up to a spatial region where it vanishes provides the deterministic orbit which brings the system back to its initial rest state. The control of such structures may open the way to novel applications of localized structures beyond that of simple stationary bits. PMID:24476270

Turconi, M; Giudici, M; Barland, S

2013-12-01

415

Self excitation of iron core homopolar generators  

NASA Astrophysics Data System (ADS)

In the interest of reducing homopolar generator (HPG) auxiliary requirements, a self-excited field coil for pulsed duty, iron-core HPG has been developed and tested at the Center for Electromechanics at the University of Texas. In order to minimize rotor energy expended during excitation, a low-resistance, low-inductance coil was desired to allow field current to rise as rapidly as possible. A seven-turn field coil, having a nominal resistance of 500 micro-ohms was fabricated for the compact HPG system tester and subsequently tested. At 6,000 rpm, a field current rise time of 1 sec was achieved and resulted in an average peak field density of 1.94 T. Only 300 kJ, about 13 percent of the 2.27 MJ stored in the rotor was required to fully excite the generator.

Perkins, D. E.; Nalty, K. E.; Walls, W. A.

1986-11-01

416

Radiation chemical effects of X-rays on liquids  

SciTech Connect

This review describes some of the chemical changes induced by photoelectrons which are released in liquids when X-rays are absorbed. Both experimental studies and theory are discussed. In part 1, the basic processes occurring upon absorption of X-rays are described. Parts 2 and 3 deal with hydrocarbon liquids; in part 2 the ion yields, including effects at K-edges, and in part 3, the yields of excited states. Part 4 discusses chemical effects of X-rays in aqueous solutions. The authors end with a summary of future needs and directions.

Holroyd, R.A.; Preses, J.M.

1998-11-01

417

Surface waves on non-Newtonian viscoelastic liquids  

NASA Astrophysics Data System (ADS)

In the present work, we study the dynamics of thermally excited fluctuations on the surface of non-Newtonian viscoelastic liquids, which shows complex behaviors such as crossover between the capillary wave and the elastic wave, and the coexistence of several modes. We show that the power spectrum is separated into surface localized modes and the bulk shear modes, and they are decomposed further into several modes using the partial fraction expansion. The peak positions of these modes are characterized by roots of a polynomial equation. We calculate the decomposition of the surface wave spectra numerically, and discuss evolution of constituent peaks with liquid parameters.

Ohmasa, Y.; Yao, M.

2011-03-01

418

SSI effects for a tank containing two liquids  

SciTech Connect

Following a brief review of a mechanical model which permits consideration of the flexibility of the tank wall and the supporting medium, the effects of the soil-structure interaction on the dynamic response of a laterally excited tank that contains two liquids are examined. The quantities examined include the hydrodynamic pressure, base shear and moments. The results are compared with those obtained with no soil-structure interaction. Only the impulsive component of response is examined; the convective component is for all practical purposes unaffected by soil-structure interaction. It is shown that for the conditions considered, soil-structure interaction reduces the peak response of the tank-liquid system.

Tang, Yu

1994-06-01

419

A lateral field excited ZnO film bulk acoustic wave sensor working in viscous environments  

NASA Astrophysics Data System (ADS)

We present a lateral field excited ZnO film bulk acoustic resonator (FBAR) operated in pure-shear mode and analyze its performances in viscous liquids. The electrodes of the device are located on the film surface and normal to the c-axis of the ZnO film. The proposed device works near 1.44 GHz with a Q-factor up to 360 in air and 310 in water, which are higher than those of the quasi-shear thickness field excited FBAR. The resonant frequency is decreased with the increasing square root of the product of the viscosity and density with a linear dependence in the viscosity below 148.7 mPa s. The mass sensitivity of 670 Hz cm2 ng-1 was measured by monitoring the frequency change during the volatilization of saline solution loaded on the resonator. In addition, the levels of the noise and the mass resolutions were measured in various viscous environments. The proposed device yields the mass resolution of 670 Hz cm2 ng-1 and the high mass resolution of 0.06 ng cm-2. These results indicated that the lateral field excited ZnO FBAR had superior sensitivity for the bio-sensing applications in viscous biological liquids.

Chen, Da; Wang, Jingjing; Xu, Yan; Li, Dehua; Zhang, Liuyin; Liu, Weihui

2013-09-01

420

Spin Excitations in Fe(Se,Te)  

NASA Astrophysics Data System (ADS)

The full spectrum of magnetic excitations in both superconducting FeTe0.51Se0.49 (x=0.49) and non- superconducting Fe1.04Te0.73Se0.27 (x=0.27) was studied using inelastic neutron scattering on single crystal samples. The magnetic excitations are two-dimensional in nature and are observed for energy transfers as high as 300 meV. The zero energy extrapolation of the measured dispersion shows incommensurate excitations emanating from a wavevector near (0.5,0.5), the location of the resonance in the superconducting material. For low energy transfers, the spectrum consists of a set of incommensurate spots, four-fold symmetric about the (1,0) (square lattice (?,?)) wavevector. At higher energies, these spots evolve into rings centered on Q=(1,0). These excitations are notably different than the cones of scattering expected from a long-range magnetically ordered material and likely reflect the itinerant nature of the magnetism. The qualitative evolution of the incommensurate excitation spectrum is similar that seen previously in the cuprates. Despite the incommensurate nature of the spectrum, the observed resonance in the x=0.49 sample remains peaked at the (0.5,0.5) wavevector as in other Fe-based superconductors. At low energies, the x=0.27 sample exhibits an additional feature in the excitation spectrum centered near Q=(0.5,0), the wavevector of magnetic order in Fe1+yTe. This scattering persists for all energies below about 10 meV and forms the short range order observed for this concentration. This scattering is completely absent in the x=0.49 sample which contains no excess Fe.

Lumsden, Mark

2011-03-01

421

LMM Auger primary excitation spectra of copper  

NASA Astrophysics Data System (ADS)

The shape and intensity of measured Auger peaks are strongly affected by extrinsic excitations due to electron transport out of the surface and to intrinsic excitations induced by the sudden creation of the two static core holes. Following a method developed for XPS in a previous work [N. Pauly, S. Tougaard, F. Yubero, Surf. Sci. 620 (2014) 17], we have calculated the effective energy-differential inelastic electron scattering cross-sections, including the effects of the surface and of the two core holes, within the dielectric response theory by means of the QUEELS-XPS software (QUantitative analysis of Electron Energy Losses at Surfaces for XPS). The Auger spectra are then modeled by convoluting this energy loss cross section with the primary excitation spectrum that accounts for all effects which are part of the initial Auger process, i.e. L-S coupling and vacancy satellite effects. The shape of this primary excitation spectrum is fitted to get close agreement between the theoretical and the experimental spectra obtained from X-ray excited Auger electron spectroscopy (XAES). We have performed these calculations of XAES spectra for various LMM Auger transitions of pure Cu (L3M45M45, L3M23M45, L3M23M23 and L2M45M45 transitions). We compare the resulting primary excitation spectra with theoretical results published in the literature and obtain reasonable quantitative agreement. In particular, we extract from experimental spectra quantitative intensities due to Coster-Kronig, shake-off and shake-up processes relative to the intensity from the “normal” Auger process.

Pauly, N.; Tougaard, S.; Yubero, F.

2014-12-01

422

Monogroove liquid heat exchanger  

NASA Technical Reports Server (NTRS)

A liquid supply control is disclosed for a heat transfer system which transports heat by liquid-vapor phase change of a working fluid. An assembly (10) of monogroove heat pipe legs (15) can be operated automatically as either heat acquisition devices or heat discharge sources. The liquid channels (27) of the heat pipe legs (15) are connected to a reservoir (35) which is filled and drained by respective filling and draining valves (30, 32). Information from liquid level sensors (50, 51) on the reservoir (35) is combined (60) with temperature information (55) from the liquid heat exchanger (12) and temperature information (56) from the assembly vapor conduit (42) to regulate filling and draining of the reservoir (35), so that the reservoir (35) in turn serves the liquid supply/drain needs of the heat pipe legs (15), on demand, by passive capillary action (20, 28).

Brown, Richard F. (Inventor); Edelstein, Fred (Inventor)

1990-01-01

423

Formalism of collective electron excitations in fullerenes  

E-print Network

We present a detailed formalism for the description of collective electron excitations in fullerenes in the process of the electron inelastic scattering. Considering the system as a spherical shell of a finite width, we show that the differential cross section is defined by three plasmon excitations, namely two coupled modes of the surface plasmon and the volume plasmon. The interplay of the three plasmons appears due to the electron diffraction of the fullerene shell. Plasmon modes of different angular momenta provide dominating contributions to the differential cross section depending on the transferred momentum.

Verkhovtsev, Alexey V; Solov'yov, Andrey V

2012-01-01

424

Laser pulses for coherent xuv Raman excitation  

E-print Network

We combine multi-channel electronic structure theory with quantum optimal control to derive Raman pulse sequences that coherently populate a valence excited state. For a neon atom, Raman target populations of up to 13% are obtained. Superpositions of the ground and valence Raman states with a controllable relative phase are found to be reachable with up to 4.5% population and phase control facilitated by the pump pulse carrier envelope phase. Our results open a route to creating core-hole excitations in molecules and aggregates that locally address specific atoms and represent the first step towards realization of multidimensional spectroscopy in the xuv and x-ray regimes.

Greenman, Loren; Whaley, K Birgitta

2014-01-01

425

Exciting Baryons: now and in the future  

SciTech Connect

This is the final talk of NSTAR2011 conference. It is not a summary talk, but rather a looking forward to what still needs to be done in excited baryon physics. In particular, we need to hone our tools connecting experimental inputs with QCD. At present we rely on models that often have doubtful connections with the underlying theory, and this needs to be dramatically improved, if we are to reach definitive conclusions about the relevant degrees of freedom of excited baryons. Conclusions that we want to have by NSTAR2021.

Michael Pennington

2012-04-01

426

Excitation of confined modes on particle arrays  

E-print Network

We describe both theoretically and experimentally the existence and excitation of confined modes in planar arrays of gold nanodisks. Ordered 2D lattices of monodispersive nanoparticles are manufactured, embedded in a silica matrix, and exposed to evanescent prism-coupling illumination, leading to dark features in the reflectivity, which signal the presence of confined modes guided along the arrays. We find remarkable agreement between theory and experiment in the frequency-momentum dispersion of the resonances. Direct excitation of these modes reveals long propagation distances and deep extinction features. This characterization of guided modes shows the great potential of metallic particle arrays for optical signal processing and distant sensing applications.

Bendaña, Xesús Manoel; Pirruccio, Giuseppe; Rivas, Jaime Gómez; de Abajo, F Javier García

2012-01-01

427

Stability of excited bosonic stellar configurations  

NASA Astrophysics Data System (ADS)

In this paper I study the problem of the dynamical stability of Bose star configurations which correspond to excited states. In particular I show that the eigenvalues of the pulsation equation, which governs the time evolution of the infinitesimal radial oscillations, are real. This, together with the theorem, proved by Lee and Pang, that for a configuration with critical central density ?crit the pulsation equation has a zero mode and the fact that for central densities much smaller than ?crit the lowest eigenvalue is positive, leads to the conclusion that the excited Bose star configurations are classically stable for central densities up to ?crit.

Jetzer, Ph.

1989-05-01

428

ATR-FTIR Study of the Decomposition of Acetic Anhydride on Fosfotungstic Wells–Dawson Heteropoly Acid Using Concentration-Modulation Excitation Spectroscopy  

Microsoft Academic Search

The decomposition of acetic anhydride in liquid phase on a fosfotungstic Wells–Dawson heteropoly acid (HPA) was investigated\\u000a by in situ ATR-FTIR spectroscopy. Transient and concentration-modulation excitation spectroscopy (MES) experiments in combination\\u000a with phase-sensitive detection (PSD) were used to monitor the solid–liquid interface. The MES method is based on the periodic\\u000a variation of a parameter of the reaction media such as,

Alejo Aguirre; Adrián L. Bonivardi; Silvana R. Matkovic; Laura E. Briand; Sebastián E. Collins

2011-01-01

429

Icosahedral order in liquids  

SciTech Connect

The possibility of icosahedral order in liquids and its role in glass transition is discussed in a broad context of statistical mechanics of liquid. It is pointed out that the structures of glasses and liquids are described both in terms of the topology of atomic bond networks as well as the local distortion of the atomic bonds. While topology plays a dominant role in covalent glasses, local distortion is likely to be more important for metallic glasses.

Egami, Takeshi [ORNL

2007-01-01

430

Modification of liquid hydrocarbons  

SciTech Connect

Improved rate of dissolution in liquid hydrocarbon fuels, of specified tert-butylstyrene copolymers capable of imparting anti-misting characteristics to the fuel, is obtained when the copolymer, following its production by aqueous emulsion polymerization of the monomers, is isolated from the resulting latex by a process of flocculation, separation, washing and drying at moderate temperatures. The copolymer thus isolated is advantageously incorporated in the liquid fuel in the form of a slurry with a hydroxylic liquid and an amine.

Roberts, T. S.; Waite, F. A.

1985-09-24

431

Liquid Crystal Optofluidics  

SciTech Connect

By employing anisotropic fluids and namely liquid crystals, fluid flow becomes an additional degree of freedom in designing optofluidic devices. In this paper, we demonstrate optofluidic liquid crystal devices based on the direct flow of nematic liquid crystals in microfluidic channels. Contrary to previous reports, in the present embodiment we employ the effective phase delay acquired by light travelling through flowing liquid crystal, without analysing the polarisation state of the transmitted light. With this method, we demonstrate the variation in the diffraction pattern of an array of microfluidic channels acting as a grating. We also discuss our recent activities in integrating mechanical oscillators for on-chip peristaltic pumping.

Vasdekis, Andreas E.; Cuennet, J. G.; Psaltis, D.

2012-10-11

432

Liquid level detector  

SciTech Connect

A liquid level sensor having a pair of upright conductors spaced by an insulator defining a first high resistance path between the conductors. An electrically conductive path is interposed between the upright conductors at a discrete location at which liquid level is to be measured. It includes a liquid accessible gap of a dimension such that the electrical resistance across the conductor when the gap is filled with the liquid is detectably less than when the gap is emptied. The conductor might also be physically altered by temperature changes to serve also as an indicator of elevated temperature.

Tokarz, Richard D. (West Richland, WA)

1982-01-01

433

Liquid Metal Transformers  

E-print Network

The room temperature liquid metal is quickly emerging as an important functional material in a variety of areas like chip cooling, 3D printing or printed electronics etc. With diverse capabilities in electrical, thermal and flowing behaviors, such fluid owns many intriguing properties that had never been anticipated before. Here, we show a group of unconventional phenomena occurring on the liquid metal objects. Through applying electrical field on the liquid metals immersed in water, a series of complex transformation behaviors such as self-assembling of a sheet of liquid metal film into a single sphere, quick mergences of separate metal droplets, controlled self-rotation and planar locomotion of liquid metal objects can be realized. Meanwhile, it was also found that two accompanying water vortexes were induced and reliably swirled near the rotating liquid metal sphere. Further, effects of the shape, size, voltage, orientation and geometries of the electrodes to control the liquid metal transformers were clarified. Such events are hard to achieve otherwise on rigid metal or conventional liquid spheres. This finding has both fundamental and practical significances which suggest a generalized way of making smart soft machine, collecting discrete metal fluids, as well as flexibly manipulating liquid metal objects including accompanying devices.

Lei Sheng; Jie Zhang; Jing Liu

2014-01-30

434

Pulse radiolysis studies on liquid alkanes and related polymers  

NASA Astrophysics Data System (ADS)

Absorption spectra of alkane radical cations, alkane excited states, and alkyl radicals and electrons in irradiated neat liquid alkanes at room temperature were assigned on subnanosecond and nanosecond time scale after an electron pulse. Two broad visible and near-infrared absorption bands of alkane excited states and radical cations, and UV absorption band of alkyl radicals were observed in neat n-alkanes. In neat cyclohexane and trans-decalin, very broad visible absorption band mainly due to alkane excited states and UV absorption band of alkyl radicals were observed. In neat neopentane and isooctane, visible absorption bands were not observed, although UV absorption bands of alkyl radicals were observed. The wavelengths of absorptive peaks of alkane radical cations and excited states become longer with increasing the number of carbon atoms of n-alkanes. The lifetimes of alkane radical cations become shorter with decreasing the number of carbon atoms of n-alkanes and are shorter than those of electrons in neat alkanes. The main processes of the alkyl radical formation finish within the time resolution of our system (about 20 ps). The alkyl radicals are produced mainly from excited radicals cations and partly from higher excited states, the lowest excited states, radical cations, and thermal hydrogen atoms. In irradiated ethylene-propylene copolymers, broad absorption bands of excited states and tail parts of absorption bands of radical cations and electrons were observed in visible and near-infrared region, although UV absorption of alkyl radicals was not confirmed lack of transparency of polymer films.

Tagawa, S.; Hayashi, N.; Yoshida, Y.; Washio, M.; Tabata, Y.

435

(abstract) Production and Levitation of Free Drops of Liquid Helium  

NASA Technical Reports Server (NTRS)

We are interested in the nucleation and behavior of quantized vorticies and surface excitations in free drops of superfluid helium. We have constructed an apparatus to maintain liquid helium drops isolated from any material container in the Earth's gravitational field, and have investigated two techniques for generating and introducing liquid drops into the region of confinement. The levitation apparatus utilizes the electrostatic force acting upon a charged liquid drop to counteract the gravitational force, with drop position stability provided by a static magnetic field acting upon the helium diamagnetic moment. Electrically neutral superfluid drops have been produced with a miniature thermomechanical pump; for a given configuration the liquid initial velocity has been varied up to several centimeters per second. Liquid drops carrying either net positive or negative charge are produced by an electrode which generates a flow of ionized liquid from the bulk liquid surface. Potentials of less than one thousand volts to several thousand volts are required. The mass flow is controlled by varying duration of the ionizing voltage pulse; drops as small as 30 micrometers diameter, charged to near the Rayleigh limit, have been observed.

Paine, C. G.; Petrac, D.; Rhim, W. K.

1995-01-01

436

Nonlinear Dual-Comb Spectroscopy with Two-Photon Excitation  

NASA Astrophysics Data System (ADS)

Dual frequency comb spectroscopy has proven to be a powerful method for acquiring broadband, high resolution spectra with measurement times that are much shorter than in traditional moving-mirror Fourier transform spectroscopy. Because the measurements are carried out with femtosecond lasers, this technique has great potential for decreasing the measurement times and improving the signal-to-noise ratio of nonlinear spectroscopic measurements, such as two-photon excitation or Raman processes. In the case of two-photon excitation, an entire spectrum can be obtained at a given signal level using dual-comb spectroscopy in the same time that a measurement of a single transition frequency would be obtained with a continuous laser of the same average power. In this presentation, I will show the latest results in extending the dual-comb technique to two-photon excitation spectroscopy, with measurements on gas-phase rubidium and liquid-phase dye samples. In our realization of dual-comb spectroscopy, two frequency combs with slightly different repetition rates are combined on a beam splitter and directed into a sample, and we measure the intensity of the resulting fluorescence as a function of time. Because of the different repetition rates, the time delay between a pulse from the first comb and the next pulse from the second comb changes linearly with time, simulating the action of the moving mirror in a traditional Michelson interferometer. The Fourier transform of the measured time-domain interferogram produces a radio-frequency spectrum that can be directly converted to a broadband optical spectrum through a linear scaling of the frequency. To achieve the highest possible resolution, it is necessary to compensate the residual relative fluctuations of the repetition rate and the carrier-envelope offset frequency of the frequency combs. Measuring RF beatnotes of each comb with two CW lasers provides two error signals that can be used to correct the recorded interferograms. This correction is applied differently for one-photon and two-photon spectra, providing a method of distinguishing the two.

Meek, S. A.; Hipke, A.; Hansch, T. W.; Picque, N.

2013-06-01

437

High resolution fluorescent bio-imaging with electron beam excitation.  

PubMed

We have developed electron beam excitation assisted (EXA) optical microscope[1-3], and demonstrated its resolution higher than 50 nm. In the microscope, a light source in a few nanometers size is excited by focused electron beam in a luminescent film. The microscope makes it possible to observe dynamic behavior of living biological specimens in various surroundings, such as air or liquids. Scan speed of the nanometric light source is faster than that in conventional near-field scanning optical microscopes. The microscope enables to observe optical constants such as absorption, refractive index, polarization, and their dynamic behavior on a nanometric scale. The microscope opens new microscopy applications in nano-technology and nano-science.Figure 1(a) shows schematic diagram of the proposed EXA microscope. An electron beam is focused on a luminescent film. A specimen is put on the luminescent film directly. The inset in Fig. 1(a) shows magnified image of the luminescent film and the specimen. Nanometric light source is excited in the luminescent film by the focused electron beam. The nanometric light source illuminates the specimen, and the scattered or transmitted radiation is detected with a photomultiplier tube (PMT). The light source is scanned by scanning of the focused electron beam in order to construct on image. Figure 1(b) shows a luminescence image of the cells acquired with the EXA microscope, and Fig. 1(c) shows a phase contrast microscope image. Cells were observed in culture solution without any treatments, such as fixation and drying. The shape of each cell was clearly recognized and some bright spots were observed in cells. We believe that the bright spots indicated with arrows were auto-fluorescence of intracellular granules and light- grey regions were auto-fluorescence of cell membranes. It is clearly demonstrated that the EXA microscope is useful tool for observation of living biological cells in physiological conditions.jmicro;63/suppl_1/i16/DFU090F1F1DFU090F1Fig. 1.(a) Optical setup of EXA microscpe, and observation results of of living MARCO-expressing CHO cells with (b) EXA microscope and (c) phase contrast microscope. We proposed the EXA microscope as a technique with high spatial resolution beyond the diffraction limit of light. A spatial resolution greater than 100 nm was achieved for the EXA microscope and the dynamic behavior of moving nanoparticles in water was observed by time lapse imaging. We also demonstrated luminescence image of living cells in culture solution without any treatments. PMID:25359807

Kawata, Yoshimasa; Nawa, Yasunori; Inami, Wataru

2014-11-01

438

Vacuum ultraviolet light production by nuclear irradiation of liquid and gaseous xenon  

NASA Technical Reports Server (NTRS)

Recent Los Alamos investigations suggest that a liquefied noble element may be the long-sought medium for a nuclear-excited laser or flashlamp. Research is needed to confirm this finding and to provide a basis for design and application studies. Quantitative and qualitative information are needed on the nature and behavior of the excited species, the effects of impurities and additives in the liquid phase under nuclear excitation, and the existence and magnitudes of nonlinear effects. Questions that need to be addressed and the most appropriate types of facilities for this task are identified.

Baldwin, G. C.

1981-01-01

439

PHOTOEMISSION AS A PROBE OF THE COLLECTIVE EXCITATIONS IN CONDENSED MATTER SYSTEMS.  

SciTech Connect

New developments in instrumentation have recently allowed photoemission measurements to be performed with very high energy and momentum resolution.[1] This has allowed detailed studies of the self-energy corrections to the lifetime and mass renormalization of excitations in the vicinity of the Fermi level. These developments come at an opportune time. Indeed the discovery of high temperature superconductivity in the cuprates and related systems is presenting a range of challenges for condensed matter physics.[2] Does the mechanism of high T{sub c} superconductivity represent new physics? Do we need to go beyond Landau's concept of the Fermi liquid?[3] What, if any, is the evidence for the presence or absence of quasiparticles in the excitation spectra of these complex oxides? The energy resolution of the new instruments is comparable to or better than the energy or temperature scale of superconductivity and the energy of many collective excitations. As such, photoemission has again become recognized as an important probe of condensed matter. Studies of the high T{sub c} superconductors and related materials are aided by the observation that they are two dimensional. To understand this, we note that the photoemission process results in both an excited photoelectron and a photohole in the final state. Thus the experimentally measured photoemission peak is broadened to a width reflecting contributions from both the finite lifetime of the photohole and the momentum broadening of the outgoing photoelectron.

JOHNSON, P.D.; VALLA, T.

2006-08-01

440

Extended application of flow microfluorometry by means of dual laser excitation.  

PubMed

A dual laser beam excitation device for flow analysis of biological particles has been developed. The aid of this arrangement is to increase the range of fluorescent agents employed so far in quantitative and qualitative cytochemistry. Combining an argon ion and a helium-cadmium laser two color fluorescence measurements were performed employing propidium iodide as a DNA stain and fluorescamine which stains total protein in fixed cells. Energy transfer processes between the antibiotic and DNA specific dye mithramycin and propidium iodide both being bound to nuclear chromatin were analyzed. Utilization of energy transfer processes is generally discussed as a mean to extract information about the structure and conformation of nuclear chromatin in situ. The application of a crypton ion laser with three lines near 400 nm and a single line at 350 nm having a light output in each range of nearly one Watt gives the opportunity of utilizing DNA fluorochromes which have an excitation maximum in the deep blue region, DNA spectra are shown employing mithramycin, the benzimidazol derivative 33258 (Hoechst) and the indol compound DAPI which has a high DNA specificity combined with a great stability under UV illumination. By separating two focussed laser beams at their intersecting points with the liquid sample stream the trajectory of each flowing cell crosses the beams sequentially, which causes a solitary dual excitation of each cell. The advantages of a solitary excitation device compared with a simultaneous one is discussed. PMID:870462

Stöhr, M; Eipel, H; Goerttler, K; Vogt-Schaden, M

1977-04-01

441

Husimi Functions of Excited Squeezed Vacuum States  

NASA Astrophysics Data System (ADS)

Based on the Husimi operator in pure state form introduced by Fan et al., which is a squeezed coherent state projector, and the technique of integration within an ordered product (IWOP) of operators, as well as the entangled state representations, we obtain the Husimi functions of the excited squeezed vacuum states (ESVS) and two marginal distributions of the Husimi functions of the ESVS.

Meng, Xiang-Guo; Wang, Ji-Suo; Liang, Bao-Long

2009-09-01

442

Self Excitation of Nano-Mechanical Pillars  

Microsoft Academic Search

Self excitation is a mechanism which is ubiquitous for electromechanical power devices such as electrical generators. This is conventionally achieved by making use of the magnetic field component in electrical generators [1], where a good example are the overall visible wind farm turbines [2]. In other words, a static force, like wind acting on the rotor blades, can generate a

Hyun S. Kim; Hua Qin; Robert H. Blick

2007-01-01

443

On the Electronically Excited States of Uracil  

SciTech Connect

Vertical excitation energies in uracil in the gas phase and in water solution are investigated by the equation-of-motion coupled-cluster and multi-reference configuration interaction methods. Basis set effects are found to be important for converged results. The analysis of electronic wave functions reveals that the lowest singlet states are predominantly of a singly excited character and are therefore well described by single-reference equation-of-motion methods augmented by a perturbative triples correction to account for dynamical correlation. Our best estimates for the vertical excitation energies for the lowest singlet n and are 5.0±0.1 eV and 5.3±0.1 eV, respectively. The solvent effects for these states are estimated to be +0.5 eV and ±0.1 eV, respectively. We attribute the difference between the computed vertical excitations and the maximum of the experimental absorption to strong vibronic interaction between the lowest A00 and A0 states leading to intensity borrowing by the forbidden transition.

Epifanovsky, Evgeny; Kowalski, Karol; Fan, Peng-Dong; Valiev, Marat; Matsika, Spiridoula; Krylov, Anna

2008-10-09

444

How to Generate Student Excitement in Science  

ERIC Educational Resources Information Center

To successfully generate student excitement in science, teachers need to be flexible regarding their curriculums. Students also need to be open to novel, hands-on experiences. This article describes a student teacher (ST) who taught a science unit on "Our Environment." She had already prepared her lesson and unit thoroughly but she changed the…

Ediger, Marlow

2005-01-01

445

Electron Impact Excitation and Ionization of Neon  

NASA Astrophysics Data System (ADS)

We have further developed the B-Spline R-matrix (BSR) code [1] to allow for a large number of pseudo-states in the close-coupling expansion. In the present work, the BSRMPS approach [2] was employed to perform semi-relativistic (Breit-Pauli) close-coupling calculations for elastic scattering, excitation, and ionization of neon from both the ground state and the metastable excited states. Coupling to the ionization continuum through the pseudo-states is important for low-energy elastic scattering (to represent polarizability effects), for excitation in the ``intermediate'' energy regime of about 1-5 times the ionization potential, and to allow for the calculation of ionization processes by transforming the results obtained for excitation of the positive-energy pseudo-states. The current results represent a significant extension of our earlier near-threshold work [3] and previous non-relativistic RMPS calculations [4,5].[4pt] [1] O. Zatsarinny, Comp. Phys. Commun. 174 (2006) 273.[0pt] [2] O. Zatsarinny and K. Bartschat, Phys. Rev. Lett. 107 (2011) 023203.[0pt] [3] O. Zatsarinny and K. Bartschat, J. Phys. B 37 (2004) 2173.[0pt] [4] C. P. Ballance and D. C. Griffin, J. Phys. B 37 (2004) 2943.[0pt] [5] C. P. Ballance et al., J. Phys. B 37 (2004) 4779.

Zatsarinny, Oleg; Bartschat, Klaus

2012-10-01

446

Persistent Histamine Excitation of Glutamatergic Preoptic Neurons  

PubMed Central

Thermoregulatory neurons of the median preoptic nucleus (MnPO) represent a target at which histamine modulates body temperature. The mechanism by which histamine excites a population of MnPO neurons is not known. In this study it was found that histamine activated a cationic inward current and increased the intracellular Ca2+ concentration, actions that had a transient component as well as a sustained one that lasted for tens of minutes after removal of the agonist. The sustained component was blocked by TRPC channel blockers. Single-cell reverse transcription-PCR analysis revealed expression of TRPC1, TRPC5 and TRPC7 subunits in neurons excited by histamine. These studies also established the presence of transcripts for the glutamatergic marker Vglut2 and for the H1 histamine receptor in neurons excited by histamine. Intracellular application of antibodies directed against cytoplasmic sites of the TRPC1 or TRPC5 channel subunits decreased the histamine-induced inward current. The persistent inward current and elevation in intracellular Ca2+ concentration could be reversed by activating the PKA pathway. This data reveal a novel mechanism by which histamine induces persistent excitation and sustained intracellular Ca2+ elevation in glutamatergic MnPO neurons. PMID:23082195

Tabarean, Iustin V.

2012-01-01

447

Nuclear excitation and precompound nuclear reactions  

SciTech Connect

The angular distribution of nucleons emitted in nucleon-induced precompound nuclear reactions are calculated taking into account the effect of excitation on the kinematics of nucleon-nucleon scattering inside the target-plus-projectile system. The results are compared with quantum mechanical calculations and those of reaction models based on a pure nucleon-nucleon collision picture.

De, A.; Ray, S.; Ghosh, S.K.

1988-06-01

448

Homopolar and bipolar hybrid excitation synchronous machines  

Microsoft Academic Search

This paper presents a description and operating principle of different hybrid excitation synchronous machines. Four prototype machines of different power rating (3 kW and 15 kW) have been studied. These machines combine two flux sources: permanent magnets, located in the rotor, and field coils, located in the stator. Thanks to this particular configuration the air gap flux can be easily

L. Vido; M. Gabsi; M. Lecrivain; Y. Amara; F. Chabot

2005-01-01

449

Excited glue and the vibrating flux tube  

E-print Network

Recent lattice results for the energy of gluonic excitations as a function of quark separation are shown to correspond to transverse relativistic flux tube vibration modes. For large quark separations all states appear to degenerate into a few categories which are predicted uniquely, given the ground state.

Theodore J. Allen; M. G. Olsson; Sinisa Veseli

1998-04-29

450

Contour Line Portraits: Excited about Artistic Abilities  

ERIC Educational Resources Information Center

In this article, the author describes a self-portrait project that encouraged students, boosted their self-confidence, and got them excited about their artistic abilities--while producing amazing results. This lesson effectively develops artistic ability by compelling students to see that drawing is quite simply breaking down objects into the…

Neal, Kari Gertz

2012-01-01

451

Excited charmonium physics from lattice QCD  

SciTech Connect

Properties of excited mesons are studied using a lattice QCD simulation of a system comparable to charmonium. We extract a spectrum of states, including those with manifestly exotic quantum numbers. Radiative transition form-factors are also computed, in particular the transition from exotic ·c1 to J /È ³ which is found to be large on the usual scale of magnetic dipole transitions.

Jozef Dudek

2009-12-01

452

Optical excitation of surface plasmons: An introduction  

Microsoft Academic Search

Beginning from low level concepts the basic understanding for the optical excitation of surface plasmons is developed. Prism coupling using the attenuated total reflection technique is discussed as well as the less traditional grating coupling technique. A brief discussion of some recent developments using twisted gratings is also presented. Finally a short summary of the potential device applications is given.

J. R. Sambles; G. W. Bradbery; Fuzi Yang

1991-01-01