We perform a systematic analysis of an extension of the Standard Model that includes a complex singlet scalar field and is scale invariant at the tree level. We call such a model the Minimal Scale Invariant extension of the Standard Model (MSISM). The tree-level scale invariance of the model is explicitly broken by quantum corrections, which can trigger electroweak symmetry breaking and potentially provide a mechanism for solving the gauge hierarchy problem. Even though the scale invariant Standard Model is not a realistic scenario, the addition of a complex singlet scalar field may result in a perturbative and phenomenologically viable theory. We present a complete classification of the flat directions which may occur in the classical scalar potential of the MSISM. After calculating the one-loop effective potential of the MSISM, we investigate a number of representative scenarios and determine their scalar boson mass spectra, as well as their ...
An alternative and graphical representation of the magnetic moment and the effective paramagnetic moment for polycrystalline Ce compounds with tetragonal site symmetry is described. The reduced moments can be calculated by means of standard perturbation theory. The calculated values deduced from the ground states of CeCu_2Si_2, CeRu_2Si_2, and CePd_2Si_2 polycrystals are compared with experimental magnetic moments.
In this review, we show how advances in the theory of magnetic pseudodifferential operators (magnetic $\\Psi$DO) can be put to good use in space-adiabatic perturbation theory (SAPT). As a particular example, we extend results of [PST03] to a more general class of magnetic fields: we consider a single particle moving in a periodic potential which is subjectd to a weak and slowly-varying electromagnetic field. In addition to the semiclassical parameter $\\eps \\ll 1$ which quantifies the separation of spatial scales, we explore the influence of additional parameters that allow us to selectively switch off the magnetic field. We find that even in the case of magnetic fields with components in $C_b^{\\infty}(\\R^d)$, e. g. for constant magnetic fields, the results of Panati, Spohn and Teufel hold, i.e. to each isolated family of Bloch bands, ...
Generation of anomalous resistivity and dynamical development of collisionless reconnection in the vicinity of a magnetically neutral sheet are investigated by means of a three-dimensional particle simulation. For no external driving source, two different types of plasma instabilities are excited in the current layer. The lower hybrid drift instability (LHDI) is observed to grow in the periphery of current layer in an early period, while a drift kink instability (DKI) is triggered at the neutral sheet in a late period as a result of the nonlinear deformation of the current sheet by the LHDI. A reconnection electric field grows at the neutral sheet in accordance with the excitation of the DKI. When an external driving field exists, the convective electric field penetrates into the current layer through the particle kinetic effect and collisionless reconnection is triggered by the convective electric field earlier than the ...
A strong toroidal rotation braking has been observed in plasmas with application of an n = 1 magneticperturbation field on the JET tokamak. Calculation results from the momentum transport analysis show that the torque induced by the n = 1 perturbation field has a global profile. The maximal value of this torque is at the plasma core region (#rho# < 0.4) and it is about half of the neutral beam injection torque. The calculation shows that the plasma is mainly in the #nu#_-#sq root##nu# regime in the plasma core, but it is close to the transition between the 1/#nu# and #nu#_-#sq root##nu# regimes. The neoclassical toroidal viscosity (NTV) torque in the 1/#nu# and #nu#_-#sq root##nu# regimes is calculated. The observed torque is of a magnitude in between that of the NTV torque in the 1/#nu# and #nu#_-#sq root##nu# regimes. The NTV torque in the #nu#_-#sq root##nu# regimes is enhanced using the Lagrangian variation of the ...
The BESS detector is a new type of balloon-borne spectrometer which utilizes various technologies recently developed for collider experiments. The principal scientific objectives include a measurement of cosmic-ray antiproton spectrum, search for anti-nuclei in cosmic radiation, and precise measurements of cosmic-ray primaries. A thin superconducting solenoidal coil produces a uniform magnetic field of 1 T. Cylindrical drift chambers are located inside and outside the coil and perform continuous tracking. The momentum resolution is 0.5% at 1 GeV/c. i.e., the maximum detectable rigidity is 200 GV. Scintillation counter hodoscopes, placed above and below the solenoid, provide timing and dE/dx measurements and trigger generation. The timing resolution is 80 ps/counter. This cylindrical configuration achieves a large geometrical acceptance of 0.35 m{sup 2} sr which is essential to detect rare cosmic-ray particles. In order to cope with high ...
Abstract in english Numerical solutions for the effects of radiation on a MHD convective heat transfer past a semi-infinite porous plate with a magnetic field are obtained. It is assumed that the porous plate moves with a constant velocity in the direction of fluid flow, and the free stream velocity follows the exponentially increasing small perturbation law. The magnetic field acts perpendicular to the porous surface which absorbs the fluid with a suction velocity varying with time. The gov (more) erning equations for the flow are transformed into a system of nonlinear ordinary differential equations by perturbation technique and then are solved numerically by using the shooting method. The effects of the various parameters on the velocity, temperature profiles as well as the surface skin-friction and surface heat transfer are illustrated graphically.
A method for systematically including topological degrees of freedom in perturbation theory is developed. This is not bound by the restrictions of semi-classical techniques. The Yang-Mills theory in three Euclidean dimensions is considered here. A well-defined separation of the topological and the ``spin wave'' degrees of freedom is obtained, motivated by a singular gauge. This has ``photons'' distorting the spherically symmetric magnetic fields of Dirac monopoles, and massless charged vector bosons ``W'' scattering off the latter. It is explicitly shown that the Dirac string does not contribute. The mode of the charged vector bosons with total angular momentum J=0 provides precisely the core to give a finite energy to the monopole. The radial equation for W is remarkably simplified and only two polarization states survive exactly for the anomalous magnetic moment required by the Yang-Mills interaction.
The first analysis of inelastic J/{psi} meson production in photoproduction (Q{sup 2}<2.5 GeV{sup 2}) of the H1 experiment for the second phase of HERA (HERA II) is presented. The analysis is carried out at low and medium elasticities. The production of heavy quarks (charm, or bottom) is of special interest since the mass of the quarks provides a hard scale for the application of perturbative QCD. The muonic decay channel is used to select the J/{psi} mesons. The data was collected by the H1 detector during the period 2003-2005, and corresponds to an integrated luminosity of 133 pb{sup -1}. However only a subset of this data could be analysed. At the start of HERA II the trigger system was affected by a sizeable background. Then a fault was introduced in the trigger software during the summer 2004 and was only discovered and solved in April 2006. This means that approximately 80 % of the ...
We study diffusion of Cosmic Rays (CRs) in turbulent magnetic fields using test particle simulations. Electromagnetic fields are produced in direct numerical MHD simulations of turbulence and used as an input for particle tracing, particle feedback on turbulence being ignored. Statistical transport coefficients from the test particle runs are compared with earlier analytical predictions. We find qualitative correspondence between them in various aspects of CR diffusion. In the incompressible case, that we consider in this paper, the dominant scattering mechanism occurs to be the non-resonant mirror interactions with the slow-mode perturbations. Perpendicular transport roughly agrees with being produced by magnetic field wandering.
Starting with two supersymmetric dual theories, we imagine adding a chiral perturbation that breaks supersymmetry dynamically. At low energy we then get two theories with soft supersymmetry-breaking terms that are generated dynamically. With a canonical K{umlt a}hler potential, some of the scalars of the ``magnetic`` theory typically have negative mass-squared, and the vector-like symmetry is broken. Since for large supersymmetry breaking the ``electric`` theory becomes ordinary QCD, the two theories are then incompatible. For small supersymmetry breaking, if duality still holds, the magnetic theory analysis implies specific patterns of chiral symmetry breaking in supersymmetric QCD with small soft masses.
We have designed a local trigger board for the Daya Bay reactor neutrino experiment, which is aimed to measure the neutrino mixing angle sin22?13 with a precision down to 1% level. The local trigger board processes both the total number of coincident photomultiplier tube (PMT) hits and the PMT energy sum to make trigger decisions. With this design, a high trigger probability is achieved to meet the system requirement. The design of the local trigger board is presented.
In this article, we studied the effects of variable viscosity and thermal conductivity on an unsteady two-dimensional laminar flow of a viscous incompressible conducting fluid past a semi-infinite vertical porous moving plate taking into account the effect of a magnetic field in the presence of variable suction. The fluid viscosity is assumed to vary as an inverse linear function of temperature but the thermal conductivity is assumed to vary as a linear function of temperature. It is assumed that the porous plate moves with a constant velocity in the direction of fluid flow, and the free stream velocity follows the exponentially increasing small perturbation law. The governing equations for the flow are transformed into a system of nonlinear ordinary differential equations by perturbation ...
PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antimatter with a precision of the order of $10^{-8}$). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, 15 2006 in a $350\\times 600 km$ orbit with an inclination of 70 degrees. The detector is composed of a series of scintillator counters arranged at the extremities of a permanent magnet spectrometer to provide charge, Time-of-Flight and rigidity information. Lepton/hadron identification is performed by a Silicon-Tungsten calorimeter and a Neutron detector placed at the bottom of the device. An Anticounter system is used offline to reject false triggers coming from the ...
PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antimatter with a precision of the order of 10^-8). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, 15, 2006 in a 350*600 km orbit with an inclination of 70 degrees. The detector is composed of a series of scintillator counters arranged at the extremities of a permanent magnet spectrometer to provide charge, Time-of-Flight and rigidity information. Lepton/hadron identification is performed by a Silicon-Tungsten calorimeter and a Neutron detector placed at the bottom of the device. An Anticounter system is used offline to reject false triggers coming from the satellite. In ...
Research performed at the Lawrence Livermore National Laboratory on the equilibrium and stability of a new class of ambient-temperature passive bearing systems is described. The basic concepts involved are: (1) Stability of the rotating system is only achieved in the rotating state. That is, disengaging mechanical systems are used to insure stable levitation at rest (when Earnshaw`s theorem applies). (2) Stable levitation by passive magnetic elements can be achieved if the vector sum of the force derivatives of the several elements of the system is net negative (i.e. restoring) for axial, transverse, and tilt-type perturbations from equilibrium. To satisfy the requirements of (2) using only permanent magnet elements we have employed periodic ``Halbach arrays.`` These interact with passive inductive loaded circuits and act as stabilizers, with the primary forces arising from axially symmetric ...
Vibrational dephasing in condensed phases is studied from both a theoretical and experimental standpoint. A theory is presented which describes the dynamics of motional or exchange processes in weakly perturbed systems. This general formalism, which has been previously used to describe motional narrowing in magnetic resonance, is applied to vibrational spectroscopy. The model treats the case of a high frequency vibration anharmonically coupled to a low-frequency vibration. Intermolecular exchange of low frequency vibrational quanta results in a temperature dependent broadening and frequency shift of the high frequency vibration. Analysis of experimental data by this model yields both the exchange rates and the anharmonic couplings.
The signature of the negative snakes from the soft X-ray cameras is very similar to the more usual snakes except that the localised region of the snake has, compared with its surroundings, decreased rather than increased emission. Circumstances where negative snakes have been seen are reviewed. The negative snake appears as a region of increased resistance and of increased impurity density. The relationship between the shear and the current perturbation is shown, and it seem probable that the magnetic shear is reversed at the point of the negative snake, i.e. that q is decreasing with radius. 6 refs., 6 figs.
Role of ballooning effect in toroidal plasmas on the transient transport problems is investigated. Due to the mode localization along the magnetic field line, a meso scale appears in a radial correlation length of fluctuating fields. This scale length introduces the interference of the gradient and flux in different radial locations. For the fluctuation which gives the gyro-Bohm-like diffusion in a stationary state, this long radial correlation of the fluctuating field causes a fast propagation of response against a rapid transient perturbation. Upper bound of transient thermal diffusivity is derived. (author)
We discuss elastic electron-deuteron (ed) scattering beyond the Born approximation. The reaction amplitude contains six generalized form factors, but only three linearly independent combinations of them (generalized charge, quadrupole, and magnetic form factors) contribute to the reaction cross section in second-order perturbation theory. We examine the two-photon exchange and find that it includes two types of diagrams, where two virtual photons are interacting with the same nucleon and where the photons are interacting with different nucleons. It is shown that the two-photon-exchange amplitude is strongly connected with the deuteron wave function at short distances.
The unsteady two-dimensional laminar flow of a viscous incompressible electrically conducting micro polar fluid via a porous medium past a semi-infinite vertical porous moving plate in the presence of a transverse magnetic field is studied. A uniform magnetic field acts perpendicularly to the porous surface in which absorbs the micro polar fluid with a suction velocity varying with time. The effects of material parameters on the velocity and temperature fields across the boundary layer are investigated. The method of solution can be applied for small perturbation approximation. Numerical results of velocity and temperature distributions of micro polar fluids are compared with the corresponding flow problems for a Newtonian fluid. (author)
The transport of magnetospheric particles in the outer cusp region is examined by means of three-dimensional single particle codes. It is shown that, at high altitudes, particles can experience nonadiabatic motions leading to significant magnetic moment changes. It is demonstrated that this nonadiabatic behavior can be interpreted, at least partly, by the action of an impulsive centrifugal force perturbing the particle gyromotion. Systematic trajectory calculations reveal that plasma sheet ions which ExB convert toward the magnetopause from low L-shells in the dayside sector are subjected to such nonadiabatic motions. As a result of magnetic moment damping, a number of them are injected into the loss cone and subsequently precipitate near the cusp equatorward edge.
Giant magnetoresistance (GMR) has been used with Eddy current testing to detect small defects not only in thin film structures but also in multilayered metallic structures. This work detected small scratches in the thin film under the surface where these defects were unable to be inspected or monitored by regular testing. In addition, rotational GMR magnetic sensor based Eddy current probes were used for detecting buried corner cracks at the edge of holes in metallic structures. The results of this study proved that giant magnetoresistance is very powerful and effective to sense the magnetic field, which is the result from the perturbation of the Eddy currents caused by a defect. This method can be used for quality control of metallization layers on silicon wafer and to detect cracks in thick structures such as cracks in aging aircraft.
Fluctuations in the flux of runaway electrons to the limiter have been measured during many PLT discharges. Oscillations at 60, 120, and 720 Hz are driven by variations in the vertical magnetic field which moves the plasma major radius. Fluctuations are seen in the range of 2 ..-->.. 20 kHz due to MHD magnetic islands which extend to the plasma surface. A continuous spectrum of fluctuations is observed up to 200 kHz which correlates with drift-wave turbulence. The magnitude of the driven fluctuations can be used to measure transport properties of the runaway electrons. The amplitude of electron motion due to the MHD and drift-wave oscillations, and hence a measure of the radial size of the instability, can be determined as a function of frequency. The slope of the frequency power spectrum of the drift-wave-induced fluctuations steepens with increasing runaway electron drift orbit displacement during the current drop at the end of the ...
We present results from an investigation of the dynamical behavior of buoyant magnetic flux rings in the radiative interior of a uniformly rotating early-type star. Our physical model describes a thin, axisymmetric, toroidal flux tube that is released from the outer boundary of the convective core, and is acted upon by buoyant, centrifugal, Coriolis, magnetic tension, and aerodynamic drag forces. We find that rings emitted in the equatorial plane can attain a stationary equilibrium state that is stable with respect to small displacements in radius, but is unstable when perturbed in the meridional direction. Rings emitted at other latitudes travel toward the surface along trajectories that largely parallel the rotation axis of the star. Over much of the ascent, the instantaneous rise speed is determined by the rate of heating by the absorption of radiation that diffuses into the tube from the external medium. Since the time ...
Vacuum arc with cathode spots on the cold electrode is widely used as a plasma generator in a such kind of devices like metal ion sources, plasma cathode electron guns, thing films deposition facilities and others. Most vacuum arc devices utilize a high voltage discharge across an insulator surface to provide a trigger plasma which in turn initiates the main arc discharge. Operation of vacuum arc in a repetitively pulsed mode required a stable triggering system for the long time. But with a discharge across the insulators the number of stable pulses is limited by 100,000 or little bit more. The better method for vacuum arc ignition is low pressure discharge. As shown in this paper it is possible to increase the lifetime of the ignition system in 10 times at least, but negative characteristic of this system is a relatively high pressure (about 0.1 mtorr). In some kinds of vacuum arc applications it is impermissible because it leads to the ...
Superconducting rf cavities are increasingly used in accelerators. Gradient is a parameter of particular importance for the ILC. Much progress in gradient has been made over the past decade, overcoming problems of multipacting, field emission, and breakdown triggered by surface impurities. However, the quenching limit of the surface magnetic field for niobium remains a hard limitation on cavity fields sustainable with this technology. Further exploration of materials and preparation may offer a path to surpassing the current limit. For this purpose, we have designed a resonant test cavity. One wall of the cavity is formed by a flat sample of superconducting material; the rest of the cavity is copper or niobium. The H field on the sample wall is 75% higher than on any other surface. Multipacting is avoided by use of a mode with no surface electric field. The cavity will be resonated through a coupling iris with high-power rf at superconducting ...
An approximate expression for whistler-mode group velocity is obtained, taking into account the effects of electron temperature and anisotropy, density and ion effects, effects of oblique propagation and a non-dipolarity of the dayside magnetospheric magnetic field. This expression is applied to the propagation of whistlers between one hemisphere and the other. It is pointed out that at frequencies close to the upper cut-off of whistler spectra, perturbations to whistler group delay times due to temperature effects can be of the same order of magnitude as, or even higher than, the corresponding perturbations due to finite electron density and ion effects. A method of magnetospheric electron temperature diagnostics is proposed and applied to two whistlers recorded at Halley (L = 4.3). It is pointed out that the values of temperature obtained from the analysis of whistler spectra depend on the choice of model of electron ...
... multivibrators and amplifiers arranged to operate as described above. ... The first of the multivibrators is triggered by the trailing edge of the ...
MAGNETIC FORMING .............. MAGNETIC INDUCTION ............ MAGNETIC MATERIALS ............ MAGNETIC MEASUREMENT .......... MAGNETIC PERMEABILITY . ...
An analysis is presented for the effects of chemical reaction and thermal radiation on hydromagnetic free convection heat and mass transfer for a micropolar fluid via a porous medium bounded by a semi-infinite vertical porous plate in the presence of heat generation. The plate moves with a constant velocity in the longitudinal direction and the free stream velocity follows an exponentially small perturbation law. A uniform magnetic field acts perpendicularly to the porous surface in which absorbs the micropolar fluid with a suction velocity varying with time. Analytical expressions are computed numerically. Numerical calculations are carried out the purpose of the discussion of the results which are shown on graphs and the effects of the various dimensionless parameters entering into the p...
The g-factor of the 21/2/sup +/ state at 1921.9 keV in /sup 203/Pb has been measured through the time differential perturbed angular distribution technique in an external magnetic field B=2.028 T. The measured g-factor g=-0.063(2) indicates a predominantly three neutron hole configuration described by the wave function 0.68vertical strokei/sup -1//sub 13/2/f/sup -2//sub 5/2/>+-0.73vertical strokei/sup -1//sub 13/2/f/sup -1//sub 5/2/p/sup -1//sub 3/2/>.
We conjecture that the end point of bulk closed string tachyon decay at any nonzero coupling is the annihilation of space-time by Witten's bubble of nothing, resulting in a topological phase of the theory. In support of this we present a variety of situations in which there is a correspondence between the existence of perturbative tachyons in one regime and the semiclassical annihilation of space-time. Our discussion will include many recently investigated scenarios in string theory including Scherk-Schwarz compactifications, Melvin magnetic backgrounds, and noncompact orbifolds. We use this conjecture to investigate a possible web of dualities relating the eleven-dimensional Fabinger-Horava background with nonsupersymmetric string theories. Along the way we point out where our conjecture resolves some of the puzzles associated with bulk closed string tachyon condensation.
The electromagnetic properties of the baryon decuplet are calculated in quenched QCD on a 20{sup 3}x40 lattice with a lattice spacing of 0.128 fm using the fat-link irrelevant clover fermion action with quark masses providing a pion mass as low as 300 MeV. Magnetic moments and charge radii are extracted from the electric and magnetic form factors for each individual quark sector. From these, the corresponding baryon properties are constructed. We present results for the higher-order moments of the spin-3/2 baryons, including the electric-quadrupole moment E2 and the magnetic-octupole moment M3. The world's first determination of a nonzero M3 form factor for the {delta} baryon is presented. With these results we provide a conclusive analysis which shows that decuplet baryons are deformed. We compare the decuplet-baryon results from a similar lattice calculation of the octet baryons. We establish that the environment ...
The results of a combined investigation of splat-quenched Fe-Csub(x) (x<0.05) alloys by resistivity, X-ray diffraction and Moessbauer spectroscopy are presented. The residual resistivity increases linearly with the carbon content (#DELTA#rho=5#mu##OMEGA#cm/at.%) with a slope identical to that observed in the dilute ferritic phase. X-ray diffraction reveals the presence of a martensite structure in addition to a small fraction of residual austenite; the dependence of the a and c lattice parameters on xsub(c) agrees with earlier measurements. A detailed investigation of the relative reflexion intensities shows that the as-quenched martensites consist of a mixing of massive martensite and tetragonal martensite for low carbon content and of tetragonal martensite only for xsub(c) approximately 0.05. The Moessbauer spectra reveal 3 or 4 magnetically non equivalent iron sites. From a detailed analysis of the intensity dependence of the subspectra on carbon content the ...
The magnetic moments of "1"7"7Ta and sup(181,182,187)Re levels decaying via the K-forbidden transitions are measured. The nuclei studied are produced via the "1"7"7W and sup(181,182)Os and "1"8"7W #beta#-decay respectively. The magnetic moments have been measured using the method of the differential #gamma##gamma# angular correlations, perturbed by an external magnetic field. The following magnetic moments and lifetimes are obtained: for the 5/2"-1/2"-[541] "1"8"1Re level with excitation energy of 357 keV #mu#/#mu#sub(n)=2.00+-0.10, Tsub(1/2)=(76+-8)x10sup(-8) s; for the 186.4 keV 5/2"-1/2"-[541] "1"7"7Ta level #mu#/#mu#sub(n)=2.02+-0.13, Tsub(1/2)=(2.78+-0.09)x10sup(-6) s; for the 236 keV 2"- "1"8"2Re level #mu#/#mu#sub(n)=2.12+-0.08; for the 203 keV 9/2"- [514] "1"8"7Re level #mu#/#mu#sub(n)=5.04+-0.09.
Perturbative approach to two-dimensional gravity and supergravity is considered. One-loop renormalization of the central charge of SL(2,R) Kac-Moody algebra is calculated perturbatively by functional integration and by explicit calculations of the Feynman diagrams. Also the wavefunction renormalization and the anomalous dimensions in the presence of gravity are calculated.
We present a high-statistics calculation of nucleon electromagnetic form factors in N{sub f}=2+1 lattice QCD using domain wall quarks on fine lattices, to attain a new level of precision in systematic and statistical errors. Our calculations use 32{sup 3}x64 lattices with lattice spacing a=0.084 fm for pion masses of 297, 355, and 403 MeV, and we perform an overdetermined analysis using on the order of 3600 to 7000 measurements to calculate nucleon electric and magnetic form factors up to Q{sup 2{approx_equal}}1.05 GeV{sup 2}. Results are shown to be consistent with those obtained using valence domain wall quarks with improved staggered sea quarks, and using coarse domain wall lattices. We determine the isovector Dirac radius r{sub 1}{sup v}, Pauli radius r{sub 2}{sup v} and anomalous magnetic moment {kappa}{sub v}. We also determine connected contributions to the corresponding isoscalar observables. We extrapolate these observables to the ...
Half-Heusler phases XYZ (Pearson symbol cF12) are chemically versatile and rich in physical properties. The half-Heusler phase in the Fe-Zn-Sb ternary system was reported in the year 2000. In this work, two new ternary phases are identified in the vicinity of the equiatomic composition FeZnSb in the same system: Fe1-xZnSb (tetragonal, space group P4/nmm, Pearson symbol tP6-?, Z=2: a=4.1113(6) A, c=6.0127(12) A for x=0.08 (1), and a=4.1274(6) A, c=6.0068(12) A for x=0.12 (2)); and Fe7.87Zn6.72Sb8 (Fe0.98Zn0.84Sb) (3) (cubic, space group Fm-3m, Pearson symbol cF96-?, Z=4, a=11.690(13) A). 1 and 2 crystallize in the PbFCl-type structure, and 3 adopts a unique 2x2x2 supercell of a normal half-Heusler structure. The structures of both the tetragonal and cubic phases can be described as assemblies of half-Heusler structure related subunits. Electrical resistivity measurement on the pure sample of 2 shows it has metallic-like behavior, and its thermal and magnetic ...
Comparative studies of flocculent and grand-design spirals suggest that density waves are not the predominant trigger of star formation in most galaxies. Implications for chemical evolution are profound. It may be possible to ignore the details of the spiral-wave phenomenon in research aimed at unifying the chemical properties of spiral disks. 16 references.
A structurally conserved element, the trigger loop, has been suggested to play a key role in substrate selection and catalysis of RNA polymerase II (pol II) transcription elongation. Recently resolved...Full Text Available
This paper describes a novel psychophysical and analytical technique, called periodic perturbation, for creating and characterizing perceptual waves associated with transitions in visibility...Full Text Available
... 4. Range Multivibrator Section: The range multivibrator section consists of five multivibrators which are sequentially triggered every 62 ýLsec of the ...
The paper describes design and practical realization of an internal communication layer referred to as the Internal Interface (II). The system was realized for the RFC Muon Trigger of the CMS experiment. Fully automatic implementation of the communication layer is realized in the FPGA chips and in the control software. The methodology of implementation was presented in the description form of the interface structure from the sides of hardware and software. The examples of the communication layer realizations were given for the RFC Muon Trigger.
By means of a global mode analysis of ideal MHD modes for Mercier-unstable equilibria in a planar axis L=2/M=10 heliotron/torsatron system with an inherently large Shafranov shift, the conjecture from local mode analysis for Mercier-unstable equilibria given in [N. Nakajima, Phys. Plasmas 3, 4556 (1996)] has been confirmed and the properties of pressure-driven modes, namely, ballooning modes and interchange modes, inherent to such three-dimensional systems have been clarified. The change of the local magnetic shear due to the Shafranov shift, which is related to toroidicity, reduces the field line bending stabilizing effects on ballooning modes. According to the degree of the reduction of the local magnetic shear by the Shafranov shift, the Mercier-unstable equilibria are categorized into toroidicity-dominant (strong reduction) and helicity-dominant (weak reduction) Mercier-unstable equilibria. Since the local magnetic ...
This contribution provides an overview and imparts basic knowledge on pertinent technical developments in magnetic resonance imaging (MRI) of the liver: 3D sequences, respiratory triggering, parallel imaging, and 3 Tesla (3T). 3D sequences can be used as T1-weighted (T1w) sequences for analyzing dynamics of contrast enhancement or as T2w sequences for MR cholangiography. Consistent improvements in respiratory triggering make it possible to obtain good image quality on T2w scans even in patients unable to hold their breath. Parallel imaging as a universal technique to accelerate image acquisition is particularly appropriate for MRI of the liver, and it has been shown that the reduced acquisition time is not achieved at the expense of image quality. Further progress in MRI of the liver can be expected with use of the 3T systems, but hitherto irrelevant problems must still be solved. Overall the innovations presented here, ...
The temporal evolution of linear toroidal ion temperature gradient (ITG) modes is studied based on a kinetic integral equation including an initial condition. It is shown how to evaluate the analytic continuation of the integral kernel as a function of a complex-valued frequency, which is useful for analytical and numerical calculations of the asymptotic damping behavior of the ITG mode. In the presence of the toroidal {nabla}B-curvature drift, the temporal dependence of the density and potential perturbations consists of normal modes and a continuum mode, which correspond to contributions from poles and from an integral along a branch cut, respectively, of the Laplace-transformed potential function of the complex-valued frequency. The normal modes have exponential time dependence with frequencies and growth rates determined by the dispersion relation while the continuum mode, which has a ballooning structure, shows a power law decay {proportional_to} t{sup -2} in ...
The biomedical and ecological interest for the microwave impact on the Earth biosphere is continuously increased since the industrial, military and communication activities strongly contribute to the electromagnetic stress of living bodies. In the next the authors present some of the main results obtained regarding the microwave exposure of various types of biological material: bacteria, fungi, young plant seedlings, dry seeds, animal tissues. The electromagnetic exposure was carried out in open space in well controlled environmental conditions by using 10.75 GHz/1 m W cm{sup -2} microwaves. Biochemical assays and cytogenetic tests have been carried out to reveal the changes induced post irradiation. The response of some pathogen bacteria, have been emphasized by means of turbidimetric measurements - the stimulatory effect being noticed at the level of the microbial population density (the stimulation of the human body microbial flora seems to be one of the side effects of microwave ...
Assessment of the roles of the carboxyl-terminal #beta#146 histidyl residues in the alkaline Bohr effect in human and normal adult hemoglobin by high-resolution proton nuclear magnetic resonance spectroscopy requires assignment of the resonances corresponding to these residues. By a careful spectroscopic study of human normal adult hemoglobin, enzymatically prepared des(His146#beta#)-hemoglobin, and the mutant hemoglobins Cowtown (#beta#146His #-># Leu) and York (#beta#146His #-># Pro), the authors have resolved some of these conflicting results. By a close incremental variation of pH over a wide range in chloride-free 0.1 M N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid buffer, a single resonance has been found to be consistently missing in the proton nuclear magnetic resonance spectra of these hemoglobin variants. The results indicate that the contribution of the #beta#146 histidyl residues is 0.52 H"+/hemoglobin tetramer at pH ...
This work aims at improving the understanding of the dynamics of a Free Electron Laser (FEL) based on a storage ring. A new phenomenon of saturation by the electron bunch transverse dimensions is pointed out, during the FEL operation with a magnetic optics ''low emittance''. A part of this thesis work concerns the study of the longitudinal dynamics of the FEL depending on a parameter: the detuning between the pass frequency of the electrons and the back and return frequency of the laser pulse in the optical cavity. This study shows that the FEL presents a pulsed or a steady state behavior depending on the detuning. Besides, a spectro-temporal behavior of the FEL is pointed out showing the FEL pulse substructures and holes in the spectrum. Another part of this work concerns the response of the resonant FEL system, when a perturbation is applied on the gain. Under the effect of a modulation, the FEL can present a periodic or chaotic regime. The ...
Recent experiments with TFTR, D-III-D and JET involving the injection and trapping of low density beams of high energy large orbit ions indicate that large orbit non-adiabatic ions slow down and diffuse classically in the presence of anomalous fluctuations and transport of adiabatic majority particles. Accordingly, we consider conceptual fusion reactors(N. Rostoker, M.W. Binderbauer and H.J. Monkhorst, Science) 278, 1419 (1997). based on classical confinement of fuel ions and fusion products(M.W. Binderbauer and N. Rostoker, J. Plasma Phys.) 56, 451 (1996).. The magnetic confinement geometry of the proposed designs is a Field Reversed Configuration. A survey of experimental results on instabilities and their characteristics as related to these reactor concepts is presented. Particular focus will be given to long wavelength (as compared to gyro-radius) and low frequency (?<< c/r_o, r_o=3D major radius of annular current ring) instabilities as they are most ...
A remarkable aspect of the interaction of Cryptococcus neoformans with mammalian hosts is a consistent increase in capsule volume. Given...Full Text Available
At Super-LHC luminosity it is expected that the standard suite of L1 triggers for CMS will saturate. Information from the tracker will be needed to reduce trigger rates to satisfy the L1 bandwidth. Tracking trigger modules which correlate information from closely-spaced sensor layers to form an on-detector momentum filter are being developed by several groups. We report on a trigger module design which utilizes three dimensional IC technology to incorporate chips which are connected both to the top and bottom sensor, providing the ability to filter information locally. A demonstration chip, the VICTR, has been submitted to the Chartered/Tezzaron two-tier 3D run coordinated by Fermilab. We report on the 3D design concept, the status of the VICTR chip and associated sensor integration utilizing oxide bonding.
We obtain the radial Dirac equations for the Plebanski metric and transform these equations into one-dimensional wave equations. Finally we conclude with the result that the electron and the neutrino fields are not superradiant.
The study of natural convection flow and heat transfer within a cylindrical annulus has received considerable attention because of its numerous applications, such as in nuclear reactor design, electronic component cooling, thermal storage systems, energy conservation, energy storage, and energy transmission. Here, the effects of multiple geometric perturbations on the inner and outer cylinders of an annulus with impermeable end walls are investigated in this work. A three-dimensional study was done using a numerical scheme based on a Galerkin method of finite element formulation. The nature of the buoyancy-induced flow field has been analyzed in detail. The flow fields for the cases considered were found to be qualitatively similar, and the introduction of each additional perturbation altered the flow field in a regular and recurring manner. The introduction of each perturbation on the outer cylinder causes clockwise and ...
The study of natural convection flow and heat transfer within a cylindrical annulus has received considerable attention because of its numerous applications, such as in nuclear reactor design, electronic component cooling, thermal storage systems, energy conservation, energy storage, and energy transmission. Here, the effects of multiple geometric perturbations on the inner and outer cylinders of an annulus with impermeable end walls are investigated in this work. A three-dimensional study was done using a numerical scheme based on a Galerkin method of finite element formulation. The nature of the buoyancy-induced flow field has been analyzed in detail. The flow fields for the cases considered were found to be qualitatively similar, and the introduction of each additional perturbation altered the flow field in a regular and recurring manner. The introduction of each perturbation on the outer cylinder causes clockwise and ...
The Stefan problem involving a source term is considered in this technical note. As an example, planar solidification with time-dependent heat generation in a semi-infinite plane is solved by use of a perturbation technique. The perturbation solution is validated by reducing the problem to the case without heat generation whose exact solution is available. An application to the case with constant heat generation is presented, for which a closed-form solution is obtained. The effects of heat generation and Stefan number on the evolution of solidification are examined using the perturbation solution.
This book presents the basic ideas of the physics of non-gravitational perturbations and the mathematics required to compute their orbital effects. It conveys the relevance of the different problems that must be solved to achieve a given level of accuracy in orbit determination and in recovery of geophysically significant parameters. Selected Contents are: Orders of Magnitude of the Perturbing Forces, Tides and Apparent Forces, Tools from Celestial Mechanics, Solar Radiation Pressure-Direct Effects: Satellite-Solar Radiation Interaction, Long-Term Effects on Semi-Major Axis, Radiation Pressure-Indirect Effects: Earth-Reflected Radiation Pressure, Anisotropic Thermal Emission, Drag: Orbital Perturbations by a Drag-Like Force, and Charged Particle Drag.
Big bang nucleosynthesis constraints on baryon isocurvature perturbations are determined. A simple model ignoring the effects of the scale of the perturbations is first reviewed. This model is then extended to address the claim that large amplitude perturbations will collapse, preventing their baryons from contributing to the observed baryon density. It is found that baryon isocurvature perturbations are constrained to provide only a slight increase in the density of baryons in the universe over the standard homogeneous model. In particular, it is found that models which rely on power laws and the random phase approximation for the power spectrum are incompatible with big bang nucleosynthesis unless an ad hoc, small-scale cutoff is included. {copyright} {ital 1995 The American Astronomical Society.}
We propose a numerical method for resummation of perturbative series, which is based on the stochastic perturbative solution of Schwinger-Dyson equations. The method stochastically estimates the coefficients of perturbative series, and incorporates Borel resummation in a natural way. Similarly to the "worm" algorithm, the method samples open Feynman diagrams, but with an arbitrary number of external legs. As a test of our numerical algorithm, we study the scale dependence of the renormalized coupling constant in a theory of one-component scalar field with quartic interaction. We confirm the triviality of this theory in four and five space-time dimensions, and the instability of the trivial fixed point in three dimensions.
Selected case studies of auroral structure/activity observed at different local times on the dayside are presented and discussed in the context of electrodynamic coupling between the different magnetospheric boundary regions and the ionosphere. The first case addresses the question of the auroral signatures of the two boundary regions referred to as cusp and cleft/LLBL. Combined ground-based and satellite data reveal the different latitudinal zones of auroral forms/particle precipitation/field-aligned current and the relationship with the respective magnetospheric plasma populations, i.e. CPS, BPS, LLBL, and the plasma mantle. Midday auroral breakup events and the related ionospheric ion drift and magnetic observations show many of the features that have been predicted to be ionospheric signatures of flux transfer events. An alternative explanation that has been proposed by others, i.e. ionospheric effect of magnetopause perturbations excited ...
A theoretical analysis of two-dimensional unsteady flow in a porous medium bounded by a horizontal wall is presented as a perturbation on a basic flow. It is assumed that the perturbation is occasioned by a sudden suction at the wall. Even for a highly permeable medium the characteristic Reynolds number in porous media flow is usually small and asymptotic solutions are developed by the Laplace transform technique. It is observed that the perturbed shear stress at the wall decays exponentially with time. (author). 5 refs.
The stability of accretion disks against short wavelength perturbations is analyzed. The disk is shown to be unstable to slow thermal perturbations propagating in the z-direction for sufficiently high values of the stress parameter ..cap alpha.. and sufficiently low values of the ratio of gas to total pressure. The acoustic flux from the ''middle region'' of the disk is estimated and discussed.
We consider the pre-Big-Bang scenario with a massive axion field which starts to dominate energy density when oscillating in an instanton-induced potential and subsequently reheats the universe as it decays into photons, thus creating adiabatic CMB perturbations. We find that the fluctuations in the axion field can give rise to a nearly flat spectrum of adiabatic perturbations with a spectral tilt {delta}n in the range -0.1< or approx. {delta}n < or approx. 1.
BackgroundThe pre-fusion form of the herpes simplex virus (HSV) fusion protein gB undergoes pH-triggered conformational change in vitro and during viral entry (Dollery...Full Text Available
Electrically triggered action potentials in the giant alga Chara corallina are associated with a transient rise in the concentration of free Ca2+ in the cytoplasm (Ca2+cyt)....Full Text Available
Diamagnetic samples placed in a strong magnetic field and a magnetic field gradient experience a magnetic force. Stable magnetic levitation occurs when the magnetic force exactly counter balances...Full Text Available
... Title : Refining the Magnetic Forming Capability. ... Abstract : The purpose of this project was to refine the in-house magnetic forming capability. ...
in pulse applications such as magnetic forming. ... In magnetic-forming electric circuitry, the ..... Aspects of Electrohydraulic land Magnetic Forming. ...
The ATLAS High Level Trigger (HLT) is a distributed real-time software system that performs the final online selection of events produced during proton-proton collisions at the Large Hadron Collider (LHC). It is designed as a two-stage trigger and event filter running on a farm of commodity PC hardware. Currently the system consists of about 850 processing nodes and will be extended incrementally following the expected increase in luminosity of the LHC to about 2000 nodes. The event selection within the HLT applications is carried out by specialized reconstruction algorithms. The selection can be controlled via properties that are stored in a central database and are retrieved at the startup of the HLT processes, which then usually run continuously for many hours. To be able to respond to changes in the LHC beam conditions, it is essential that the algorithms can be re-configured without disrupting data taking while ensuring a consistent and ...
Purpose: To visualise the vessel wall of the descending thoracic aorta using magnetic resonance imaging. To evaluate the diagnostic potential of tailored T{sub 1}-weighted sequences with contrast enhancement to assess systemic atherosclerotic disease. Methods: This study was performed on a clinical 1.5 Tesla scanner using a gradient strength of 30 mT/m and the phased array spine coil. A cadaver was examined to optimise a magnetic resonance imaging (MRI) protocol to evaluate atherosclerotic aortic wall disease. The acquired MR images were compared to gross specimens and histology. Subsequently seven patients who had undergone transesophageal ultrasound (TEU) with detailed assessment of the descending thoracic aorta were examined with MRI. The optimised protocol included untriggered and fat suppressed T{sub 2}-weighted turbo spin echo sequences and ECG-triggered and fat suppressed T{sub 1}-weighted spin echo sequences before ...
The WEGA stellarator is used to confine low temperature, overdense (densities exceeding the cut-off density of the heating wave) plasmas by magnetic fields in the range of B=50-500 mT. Microwave heating systems are used to ignite gas discharges using hydrogen, helium, neon or argon as working gases. The produced plasmas have been analyzed using Langmuir and emissive probes, a single-channel interferometer and ultra-high resolution Doppler spectroscopy. For a typical argon discharge in the low field operation, B=56 mT, the maximum electron density is n{sub e}{proportional_to}10{sup 18} m{sup -3} with temperatures in the range of T=4-12 eV. The plasma parameters are determined by using Langmuir probes and are cross-checked with interferometry. It is demonstrated within this work that the joint use of emissive probes and ultra-high resolution Doppler spectroscopy allows a precise measurement of the radial electric field. The focus of this work is on demonstrating the ...
We study the risk premium impact in the Perturbative Black Scholes model. The Perturbative Black Scholes model, developed by Scotti, is a subjective volatility model based on the classical Black Scholes one, where the volatility used by the trader is an estimation of the market one and contains measurement errors. In this article we analyze the correction to the pricing formulas due to the presence of an underlying drift different from the risk free return. We prove that, under some hypothesis on the parameters, if the asset price is a sub-martingale under historical probability, then the implied volatility presents a skewed structure, and the position of the minimum depends on the risk premium $\\lambda$.
In this paper, the authors use free field techniques in D = 2 string theory t calculate the perturbation of the special state algebras when the cosmological constant is turned on. In particular, the authors find that the 'ground cone' preserved by the ring structure is promoted to a three-dimensional hyperboloid as conjectured by Witten. On the other hand, the perturbed (1,1) current algebra of moduli deformations is computed completely, and no simple geometrical interpretation is found. The authors also quote some facts concerning the Liouville matrix a model dictionary in this class of theories.
One of the keystones of the canceled BTeV experiment (proposed at Fermilab's Tevatron) was its sophisticated three-level trigger. The trigger was designed to reject 99.9% of light-quark background events and retain a large number of B decays. The BTeV Pixel Detector provided a 3-dimensional, high resolution tracking system to detect B signatures. The Level 1 pixel detector trigger was proposed as a two stage process, a track-segment finder and a vertex finder which analyzed every accelerator crossing. In simulations the track-segment finder stage outputs an average of 200 track-segments per accelerator crossing (2.5MHz). The vertexing stage finds vertices and associates track-segments with the vertices found. This paper proposes a novel adaptive pattern recognition model to find the number and the estimated location of vertices, and to cluster track-segments around those vertices. The track clustering and vertex ...
Interkingdom signaling is established in the gastrointestinal tract in that human hormones trigger responses in bacteria; here, we show that the corollary is true, that a specific bacterial signal,...Full Text Available
By placing a discharge or 'dump' tube across an exploding bridgewire load, it is possible to by-pass the electrical energy and terminate the explosion of the wire. The dump tube is triggered by a signal derived from the energy removed from the storage cap...
We investigate a method for gene delivery to vascular smooth muscle cells using ultrasound triggered delivery of plasmid DNA from electrostatically coupled cationic microbubbles. Microbubbles...Full Text Available
Background/Objective:Three patients with spinal cord injury (SCI) and 3 able-bodied (AB) patients were infused with naloxone during a study to examine their neuroendocrine...Full Text Available
There is ample evidence suggesting that superantigens may act as a triggering factor in the pathogenesis of rheumatoid arthritis (RA). We investigated whether superantigen could activate T cells in...Full Text Available
Green leaf C6-volatiles are among the most important herbivore-induced plant volatiles (HIPVs). They play important roles in mediating the behavior of herbivores and their natural enemies, and in triggering...Full Text Available
Resistance (R) protein mediated recognition of pathogen avirulence effectors triggers signaling that induces a very robust form of species-specific immunity in plants. The soybean Rpg1-b protein mediates...Full Text Available
Cleavage of membrane-associated proteins with the release of biologically active macromolecules is an emerging theme in biology. However, little is known about the nature and regulation of the involved...Full Text Available
BackgroundNumerous microRNAs (miRNAs) have heterogeneous ends resulting from imprecise cleavages by processing nucleases and from various non-templated nucleotide additions. The...Full Text Available
Myelin-associated glycoprotein (MAG) has been implicated in inhibition of nerve regeneration in the CNS. This results from interactions between MAG and the Nogo receptor and gangliosides on...Full Text Available
The LHCb experiment that is being settled in CERN is dedicated to the study of CP violation and rare decays in the field of beauty hadrons. The phenomenological background necessary to an adequate understanding of the physics of flavor is presented in the first chapter, it is shown how the flavordynamics can open the way to new physics. The second chapter is dedicated to a brief presentation of the LHCb detector. Two aspects of the design of the muon trigger are more detailed: the radiation resistance of the opto-electronic transmitters and the simulated performances of the trigger. The third chapter reviews the tasks linked to the tagging of the savors of B mesons which will be an important step in all the experiments made at LHCb. The recent progress in heavy savor physics as well as the expected contribution of LHCb in this field are presented in the fourth chapter, especially the search for new physics in penguin diagrams b {yields} s.
Bone remodeling is necessary to avoid microdamage accumulation, which could lead to whole-bone failure. Previous studies have shown that this bone-repair mechanism is triggered by osteocyte apoptosis....Full Text Available
Neuronal death is known to trigger reactive microgliosis. However, little is known regarding the manner by which microglia are activated by injured neurons and how microgliosis participates...Full Text Available
Exteriorized phosphatidylserine (PS) residues in apoptotic cells trigger rapid phagocytosis by macrophage scavenger receptor pathways. Mimicking apoptosis with liposomes containing PS may represent...Full Text Available
May 10, 2009 ... The estimated magnitude is 18.95 with a 1-sigma error of about 0.17. ... The points of contact for this burst is Masanori Ohno .... 80 seconds after the BAT trigger with a settling exposure in the UVOT v filter. ...
Dectin-1, the major β-glucan receptor in leukocytes, triggers an effective immune response upon fungal recognition. Here we use sortase-mediated transpeptidation, a technique that allows placement...Full Text Available
Salinisation of freshwater has been identified as a serious environmental issue in Australia and around the world. Protective concentrations (trigger values) for salinity can be used to manage salinity impacts, though require locally relevant salinity tolerance information. 72-h acute salinity tolerance values were determined for 102 macroinvertebrates collected from 11 locations in four biologically distinct freshwater bio-regions in Northeast Australia and compared with sensitivities observed in Southeast Australia. The salinity tolerance of individual taxa was consistent across Northeast Australia and between Northeast and Southeast Australia. However, two distinct communities were identified in Northeast Australia using distributions of the acute tolerance values and a calculated index of salinity sensitivity. Salinity trigger values should therefore be representative of local or regionally relevant communities and may be adequately ...
New experiences can trigger changes in gene expression in the brain. To understand this phenomenon better, we studied zebra finches hearing playbacks of birdsong. Earlier research had shown that initial...Full Text Available
Genome endoreduplication during mammalian development is a rare event for which the mechanism is unknown. It first appears when fibroblast growth factor 4 (FGF4) deprivation induces differentiation...Full Text Available
An approach to generate mimics of phosphorylated serine proteins chemically through site-specific sulfonation of cysteine is presented. This chemical modification is reversible in the presence of reducing agent and therefore is analogous to the kinase/phosphatase system used in nature. PMID:21717004
Cytokinins are distributed through the vascular system and trigger responses of target cells via receptor-mediated signal transduction. Perception and transduction of the signal can occur at the plasma...Full Text Available
In the cellular immune response, recognition by CTL-TCRs of viral antigens presented as peptides by HLA class I molecules, triggers destruction of the virally infected cell (Townsend, A.R.M., J. Rothbard,...Full Text Available
BackgroundPeriodontal disease in diabetic patients presents higher severity and prevalence; and increased severity of ligature-induced periodontal disease has been verified in diabetic...Full Text Available
One hundred and seventy-nine patients completed a questionnaire focusing on adverse reactions to dental local anesthetics as manifested by 16 signs and symptoms. Twenty-six percent of the participants...Full Text Available
The nuo-6 and isp-1 genes of C. elegans encode, respectively, subunits of complex I and III of the mitochondrial respiratory chain. Partial loss-of-function...Full Text Available
We study perturbations of a Schwarzschild black hole in Chern-Simons modified gravity. We begin by showing that Birkhoff's theorem holds for a wide family of Chern-Simons coupling functions, a scalar field present in the theory that controls the strength of the Chern-Simons correction to the Einstein-Hilbert action. After decomposing the perturbations in spherical harmonics, we study the linearized modified field equations and find that axial and polar modes are coupled, in contrast to general relativity. The divergence of the modified equations leads to the Pontryagin constraint, which forces the vanishing of the Cunningham-Price-Moncrief master function associated with axial modes. We analyze the structure of these equations and find that the appearance of the Pontryagin constraint yields an overconstrained system that does not allow for generic black hole oscillations. We illustrate this situation by studying the case characterized by a ...
The problem in perturbation theory in general relativity is finding a natural gauge which simplifies the equations considerably. We solved the first and second order perturbation equations in the ''Lorentz gauge'' using the two-timing method. The equations were deduced from the equations of Einstein in the presence of a matter energy-momentum tensor of a perfect fluid with equation of state p = (#gamma#-1) rho. It is found that the 0--0 component of the first order equations together with the gauge conditions are consistent with the Bianchi type V model, without axial symmetry. It represents a ''ground state'' situation of the Bianchi type IX model (Mixmaster model.) The second order equations, describing the reaction back of the gravitational waves on the slowly varying background, give rise to rotation and will disturb the isotropization mechanism. The numerical solutions show all the features which are expected to appear. Moreover, it is ...
We write a space-time Feynman Path Integral representation for scattered wave fields from a weakly/compact supported anisotropic non-homogeneity. (author)
The authors solve the instability of perturbative vacuum of Gross-Neveu model. They use a variational method. The analysis is nonperturbative as it uses only equal time commmutator/anticommutator algebra.
We discuss the renormalisation properties of the complete set of {delta}B=2 four-quark operators with the heavy quark treated in the static approximation. We elucidate the role of heavy quark symmetry and other symmetry transformations in constraining their mixing under renormalisation. By employing the Schroedinger functional, a set of non-perturbative renormalisation conditions can be defined in terms of suitable correlation functions. As a first step in a fully non-perturbative determination of the scale-dependent renormalisation factors, we evaluate these conditions in lattice perturbation theory at one loop. Thereby we verify the expected mixing patterns and determine the anomalous dimensions of the operators at NLO in the Schroedinger functional scheme. Finally, by employing twisted-mass QCD it is shown how finite subtractions arising from explicit chiral symmetry breaking can be avoided completely. (Orig.)
The preliminary design of the read-out system for the GEM (Gammas, Electrons, Muons) detector at the Superconducting Super Collider is presented. The system reads all digitized data from the detector data sources at a Level 1 trigger rate of up to 100 kHz. A total read-out bandwidth of 40 GBytes/s is available. Data are stored in buffers that are accessible for further event filtering by an on-line, processor farm. Data are transported to the farm only as they are needed by the higher-level trigger algorithms, leading to a reduced bandwidth requirement in the Data Acquisition System.
Magnetic separation of several classes of antibiotics was investigated using electrochemical magnetic seeding. Electrocoagulation with a sacrificial anode followed by addition of magnetite particles was applied for the magnetic seeding of antibiotics. With electrochemical magnetic seeding using an iron anode, tetracycline antibiotics (oxytetracycline, chlortetracycline, doxycycline and tetracycline) and cephalosporin antibiotic (cefdinir) were rapidly removed from synthetic wastewater by magnetic separation using a neodymium magnet. Iron and aluminium anodes were suitable for magnetic seeding of the antibiotics. The results indicated that the ability of antibiotics to form strong complex with iron and aluminium allowed the higher removal by magnetic separation. This method would be appropriate for rapid treatment of ...
The cross sections of neutral tensor mesons T=a_2, f, f', ... production in the exclusive #gamma##gamma##->#TT' or semiexclusive #gamma##gamma##->#TX processes (three gluon exchange) in the semihard region s>>vertical stroketvertical stroke>1 GeV"2 are calculated. The relation of investigated processes to the problem of perturbative Odderon is discussed. The possibility of measurements at LEP and at a future #gamma##gamma#-colliders is discussed too. (orig.).
Quark-hadron duality addresses some of the most fundamental issues in strong interaction physics, in particular the nature of the transition from the perturbative to non-perturbative regions of QCD. I summarize recent developments in quark-hadron duality in lepton-hadron scattering, and outline how duality can be studied at future high-luminosity facilities such as Jefferson Lab at 12 GeV, or an electron-hadron collider such as EPIC.
Comparison of plasma density increase was carried out in outer and inner channels of the interferometer in T-11M tokamak. There were two cases of gas puffing: by outer valve or upper one. Amplitude of difference of the plasma density increase consisted of 9% near the outer valve. Perturbation of the electric potential e?1/Te can have similar value. This perturbation can lead to appearance of the additional losses.
The field algebra of the minimal models of W-algebras is amenable to a very simple description as a polynomial algebra generated by a few elementary fields, corresponding to order parameters. Using this description, the complete Landau-Ginzburg lagrangians for these models are obtained. Perturbing these lagrangians we can explore their phase diagrams, which correspond to multicritical points with D[sub n] symmetry. In particular, it is shown that there is a perturbation for which the phase structure is similar to that of the IRF models of Jimbo et al. (orig.)
The field algebra of the minimal models of W-algebras is amenable to a very simple description as a polynomial algebra generated by a few elementary fields, corresponding to order parameters. Using this description, the complete Landau-Ginzburg lagrangians for these models are obtained. Perturbing these lagrangians we can explore their phase diagrams, which correspond to multicritical points with D_n symmetry. In particular, it is shown that there is a perturbation for which the phase structure is similar to that of the IRF models of Jimbo et al. (orig.).
Over 7000 events containing a fully reconstructed D{bar D} pair have been extracted from data recorded by the FOCUS photoproduction experiment at Fermilab. Preliminary results from a study of correlations between D and {bar D} mesons are presented. Correlations are used to study perturbative QCD predictions and investigate non-perturbative effects. We also present a preliminary result on the production of {psi}(3770).
Two crucial properties of QCD, confinement and chiral symmetry breaking, cannot be understand within the context of conventional Feynman perturbation theory. Non-perturbative phenomena enter the theory in a fundamental way at both the classical and quantum level. Over they years a coherent qualitative picture of the interplay between chiral symmetry, quantum mechanical anomalies, and the lattice has emerged and is reviewed here.
This paper describes the effects of motion of beam components (quads, rf cavities and dipoles) on the beam and considers the properties of a compensation system from the perspective of users. The system departs from standard practice in considering active perturbation of the electron beam to verify beam corrections. The effects of local closed orbit perturbations to direct undulator beams at different experimental setups are also considered.
An algebraic formulation of the electromagnetic field in which various quantization procedures can be described was chosen to discuss perturbation calculations. It is shown that the Feynman rules and the second order calculation of the self-energy of the electron can be developed on the basis of the Fermi method of quantization. The algebraic approach clarifies the problems in defining the vacuum and other states which are associated with calculations in terms of field algebra operators. It is demonstrated that the vacuum state defined on the field algebra by Schwinger leads to incorrect results in the self-energy calculation.
This thesis consists of three parts. In the first part we review the quantization of Yang-Mills theories and perturbative quantum gravity in curved spacetime. In the second part we calculate the Feynman propagators of the Faddeev-Popov ghosts for Yang-Mills theories and perturbative quantum gravity in the covariant gauge. In the third part we investigate the physical equivalence of covariant Wightman graviton two-point function with the physical graviton two-point function. The Feynman propagators of the Faddeev-Popov ghosts for Yang-Mills theories and perturbative quantum gravity in the covariant gauge are infrared (IR) divergent in de Sitter spacetime. We point out, that if we regularize these divergences by introducing a finite mass and take the zero mass limit at the end, then the modes responsible for these divergences will not contribute to loop diagrams in computations of time-ordered products in either Yang-Mills ...
A diagrammatic approach to calculate n-point correlators of the primordial curvature perturbation \\zeta was developed a few years ago following the spirit of the Feynman rules in Quantum Field Theory. The methodology is very useful and time-saving, as it is for the case of the Feynman rules in the particle physics context, but, unfortunately, is not very well known by the cosmology community. In the present work, we extend such an approach in order to include not only scalar field perturbations as the generators of \\zeta, but also vector field perturbations. The purpose is twofold: first, we would like the diagrammatic approach (which we would call the Feynman-like rules) to become widespread among the cosmology community; second, we intend to give an easy tool to formulate any correlator of \\zeta for those cases that involve vector field perturbations and that, therefore, may generate prolonged ...
This paper addresses the stability aspects of several successful dc superconducting magnets such as large bubble chamber magnets, and magnets for the Mirror Fusion Test Facility and MHD Research Facility. Specifically, it will cover Argonne National Laboratory 12-Foot Bubble Chamber magnets, the 15-foot Bubble Chamber magnets at Fermi National Laboratory, the MFTF-B Magnet System at Lawrence Livermore National Laboratory, the U-25B Bypass MHD Magnet, and the CFFF Superconducting MHD magnet built by Argonne National Laboratory. All of these magnets are cooled in pool-boiling mode. Magnet design is briefly reviewed. Discussed in detail are the adopted stability critera, analyses of stability and disturbance, stability simulation, and the final results of magnet ...
We investigate the magnetic braking of the core of an axisymmetric cloud whose rotation axis is parallel to the mean direction of the magnetic field. (author).
Checks are performed on the alignment of the magnets in the LHC tunnel. It is vital that each magnet is placed exactly where it has been designed so that the path of the beam is precisely controlled.
The magnetic fluid is a colloidal suspension of magnetite in kerosene, prepared by a low-cost process. Separation is accomplished in an open trough filled with magnetic fluid. A magnetic field is established in the fluid, by energizing an electromagnet having poles on each side of the trough. Due to the design of the magnet poles and air gaps, the magnetic field is strongest at the bottom, about 10,000 oersteds, and uniformly decreases in strength to about 2000 oersteds at the top of the fluid. Therefore, the magnetic field gradient increases with depth. The magnetic force attracts the entire separation medium (magnetic fluid) creating a reaction force of equal magnitude and acting in the opposite direction. This reaction created within a magnetic fluid/magnetic field combination ...
Two branches of research are conducted in this thesis. The first deals with nonlinear combustion response as a mechanism for triggering combustion instabilities in solid rocket motors. A nonlinear wave equation is developed to study a wide class of combustion response functions to second-order in fluctuation amplitude. Conditions for triggering are derived from analysis of limit cycles, and regions of triggering are found in parametric space. Introduction of linear cross-coupling and quadratic self-coupling among the acoustic modes appears to be how the nonlinear combustion response produces triggering to a stable limit cycle. Regions of initial conditions corresponding to stable pulses were found, suggesting that stability depends on initial phase angle and harmonic content, as well as the composite amplitude, of the pulse. Also, dependence of nonlinear stability upon system parameters is considered. ...
Objective: To explore the feasibility of real-time monitoring exposure dose and image quality by using the data stored in the DICOM image archive of direct digital radiography system. Methods: Model TO. 16 was exposed, the current increased gradually from 0.5 to 125 mAs. The displayed number of model A( diameter 11.1 mm), D (diameter 4.0 mm) and J( diameter 0.7 mm) were recorded, and the detect factors (H_T) was also calculated. Images were sent to workstation before the end of DR examination. An automatic procedure was implemented to extract dose data and exposure parameters from the DICOM header file. Maximum, minimum and 3rd quartile values were preinstalled. Mean values exceeding the threshold trigger alarm signal to guide radiologist to explore the cause. Results: When the current of point A was less than 10 mAs and the current of point D and J were less than 16 mAs, the detect factor (H_T) increased with the rise of current. While point A located within ...
Rare Earth Cobalt (REC) permanent magnets have unique properties that permit solutions to some optical tasks that cannot be accomplished with conventional magnets. A review of design and of performance characteristics of these magnets includes an analytical description of the three dimensional fringe fields of REC quadrupoles.
T_2 weighted ultra-short turbo spin echo sequences were used in five individuals with variations in echo times, delayed triggering and echo intervals. To reduce movement artifacts all examinations were carried out with ECG and respiratory triggering. The sequences giving optimal image quality were then employed in 19 patients having various pulmonary abnormalities. Image resolutions, artifacts, image contrasts and diagnostic value were then judged by two observers and compared with CT. In the first study, a diastole-triggered UTSE sequence with the shortest echo proved optimal (T_E=90 ms, T_R=2-4 s, echo=9 ms, turbo factor=19). In the patient series studied, MRT was inferior to CT with regard to resolution and number of artifacts, but better in respect of contrast and diagnostic value. Using UTSE of the lung, MRT can produce images of good quality. Compared with CT, contrast is better with MRT, offering diagnostic ...
We have combined perturbative unitarity and renormalisation group equation arguments in order to find a dynamical way to constrain the space of the gauge couplings ($g'_1$, \\widetilde{g}$) of the so-called "Minimal $Z'$ Models". We have analysed the role of the gauge couplings evolution in the perturbative stability of the two-to-two body scattering amplitudes of the vector and scalar sectors of these models and we have shown that perturbative unitarity imposes an upper bound that is generally stronger than the triviality constraint. We have also demonstrated how this method quantitatively refines the usual triviality bound in the case of benchmark scenarios such as the $U(1)_\\chi$, the $U(1)_R$ or the "pure" $U(1)_{B-L}$ extension of the Standard Model. Finally, a description of the underlying model structure in Feynman gauge is provided.
We study the finite temperature electroweak transition with non-perturbative lattice Monte Carlo simulations. We find that it is of first order, at least for Higgs masses up to 80 GeV. The critical temperature of the phase transition is found to be smaller than that determined by a 2-loop renormalization group improved effective potential. The jump of the order parameter at the critical temperature is considerably larger than the perturbative value. By comparing lattice data and perturbation theory, we demonstrate that the latter, for the computation of the vacuum expectation value of the Higgs field v(T) in the broken phase at given temperature, converges quite well, provided v(T)/T>1. An upper bound on the Higgs mass necessary for electroweak baryogenesis in the light of the lattice data is briefly discussed.
We follow the evolution of the curvaton on superhorizon scales and check that the spectral tilt of the curvaton perturbations is unchanged as the curvaton becomes non-relativistic. Both inflation and pre-big bang cosmology can be treated since the curvaton mechanism within the two scenarios works the same way. We also discuss the amplitude of the density perturbations, which leads to some interesting constrains on the pre-big bang scenario. It is shown that within a SL(3,R) non-linear sigma model one of the three axions has the right coupling to the dilaton and moduli to yield a flat spectrum with a high string scale, if a quadratic non-perturbative potential is generated and an intermediate string phase lasts long enough.
Within a fully relativistic framework, we derive and solve numerically the perturbation equations of relativistic stars, including the stresses produced by a non-vanishing shear viscosity in the stress-energy tensor. With this approach, the real and imaginary parts of the frequency of the modes are consistently obtained. We find that, approaching the inviscid limit from the finite viscosity case, the continuous spectrum is regularized and we can calculate the quasi-normal modes for stellar models that do not admit solutions at first order in perturbation theory when the coupling between the polar and axial perturbations is neglected. The viscous damping time is found to agree within factor 2 with the usual estimate obtained by using the eigenfunctions of the inviscid limit and some approximation for the energy dissipation integrals. We find that the frequencies and viscous damping times for relativistic $r-$modes lie ...
The non-perturbative validity of covariant BRST-quantization of gauge theories on compact Euclidean space-time manifolds is reviewed. BRST-quantization is related to the construction of a Topological Quantum Field Theory (TQFT) of Witten type on the gauge group. The criterion for the non-perturbative validity of the quantization is that the partition function of the corresponding TQFT does not vanish and that its (equi-variant) BRST-algebra is free of anomalies. I sketch the construction of a TQFT whose partition function is proportional to the generalized Euler-characteristic of the coset space S U (n){sub gauge} / SU(n){sub global} with an associated equi-variant BRST-algebra that manifestly preserves translational symmetry. Some non-perturbative consequences of this approach are discussed. (author)
The Fourier transform of cosmological density perturbations can be represented in terms of amplitudes and phases for each Fourier mode. We investigate the phase evolution of these modes using a mixture of analytical and numerical techniques. Using a toy model of one-dimensional perturbations evolving under the Zel'dovich approximation as an initial motivation, we develop a statistic that quantifies the information content of the distribution of phases. Using numerical simulations beginning with more realistic Gaussian random-phase initial conditions, we show that the information content of the phases grows from zero in the initial conditions, first slowly and then rapidly when structures become non-linear. This growth of phase information can be expressed in terms of an effective entropy: Gaussian initial conditions are a maximum entropy realisation of the initial power spectrum, gravitational evolution decreases the phase entropy. We show that ...
The Goldstone-Brueckner perturbation theory is extended to incorporate in a simple way correlations associated with large amplitude collective motions in nuclei. The new energy expansion making use of non-orthogonal vacua still allows to remove the divergences originating from the hard-core of the bare interaction. This is done through the definition of a new Brueckner matrix summing generalized Brueckner ladders. At the lowest-order, this formalism motivates variational calculations beyond the mean-field such as the Generator Coordinate Method (GCM) and the Projected Mean-Field Method from a perturbative point of view for the first time. Going to higher orders amounts to incorporate diabatic effects in the GCM and to extend the projection technique from product states to well-defined correlated states.
We consider perturbations of a particular type (homogeneous of Bianchi type IX) from a closed Friedmann-Robertson-Walker model. By considering a perfect fluid, we obtain closed-form solutions for the perturbations in three interesting cases: stiff matter, radiation, and dust. As a cosmological application, we obtain an upper limit on the relative shear, (sigma/theta)_0 < b/sub 0exp/, if the microwave background radiation was last scattered at a mean red-shift element of [7,10"3] and the density parameter is #OMEGA# element of (1,10), where b/sub 0exp/ is the relative root-mean-square deviation of the temperature over the whole sky.
We investigate the reaction pn {yields}d{pi} {pi} in the framework of Chiral Perturbation Theory (ChPT). For the first time a complete calculation of the leading-order contributions is presented. We identify various diagrams that are of equal importance as compared to those recognized in earlier works. The diagrams at leading order behave as expected by the power counting. Also for the first time the nucleon-nucleon interaction in the initial, intermediate and final state is included consistently and found to be very important. Although the perturbative series for the production operator is expected to converge very slowly, this study provides the theoretical basis for a future evaluation of the non-resonant contributions in two-pion production reactions in nucleon-nucleon collisions. (orig.)
Major forecast errors on the background error covariance from initial conditions, atmospheric forcing, model open boundary conditions, and the river discharges are examined in a coastal model of northern South China Sea. The analysis of background error covariance matrix produced by model ensemble shows that the perturbations of the initial conditions and atmospheric forcing play major roles in producing and maintaining the amplitude of ensemble spread except for the sea surface height (SSH) field. The perturbation of model open boundary conditions can influence ensemble spread of all variables and covariance between temperature and velocity or between temperature and SSH. The perturbation of river discharge mainly affects the covariance of salinity in river estuary. A data assimilation ex...
... in the design of such devices as fusion reactors, magnetohydrodynamic generators, magnetically levitated vehicles, magnetic forming devices, and ...
This paper traces the development and progress of magnetic suspension systems and magnetic bearings in the USSR. The paper describes magnetic bearings for turbomachines, magnetic suspension systems for vibration isolation, some special measuring devices, wind tunnels, and other applications. The design, principles of operation, and dynamic characteristics of the system are presented.
In order to examine the state of technology of all areas of magnetic suspension and to review related recent developments in sensors and controls approaches, superconducting magnet technology, and design/implementation practices, a symposium was held. The proceedings are presented. The sessions covered the areas of bearings, sensors and controls, microgravity and vibration isolation, superconductivity, manufacturing applications, wind tunnel magnetic suspension systems, magnetically levitated trains (MAGLEV), space applications, and large gap magnetic suspension systems.
The CDF II eXtremely Fast Tracker (XFT) is the trigger processor which reconstructs charged particle tracks in the CDF II central outer tracking chamber. The XFT tracks are also extrapolated to the electromagnetic calorimeter and muon chambers and are associated to electromagnetic clusters and muon stubs to generate trigger electron and muon candidates. The steady increase of the Tevatron instantaneous luminosity and the resulting higher occupancy of the chamber demanded an upgrade of the original system, which performed tracking only in the transverse plane of the chamber and was consequently affected by a significant level of fake tracks. In the upgraded XFT, tracking is reinforced by using additional data from the stereo layers of the chamber to reduce the level of fake tracks and to perform three-dimensional track reconstruction. A review of this upgrade is presented.
We analyze the nucleon axial-vector coupling to two loops in chiral perturbation theory. We show that chiral extrapolations based on this representation require lattice data with pion masses below 300 MeV.
Protein modifications such as phosphorylation are often studied by two-dimensional gel electrophoresis since the perturbation in the protein’s pI value is readily detected by this method....Full Text Available
Onset of convection in a layer of couple-stress fluid-saturated porous medium is investigated for different types of basic temperature gradients. The boundaries are considered to be adiabatically insulated to temperature perturbations. The eigenvalue equations of the perturbed state obtained from the normal mode analysis are solved analytically using a regular perturbation technique with wave number as a perturbation parameter and also numerically using the Galerkin technique. The critical stability parameters obtained from these two techniques are in excellent agreement and an increase in the value of couple-stress parameter is found to delay the onset of convection. The results also indicate that the piecewise linear temperature profile hastens the onset of convection when compared to linear, parabolic, and inverted parabolic temperature profiles. In addition, the influence of thermal depth on the ...
The problem in perturbation theory in general relativity is finding a natural gauge which simplifies the equations considerably. We solved the first and second order perturbation equations in the ''Lorentz gauge'' using the two-timing method. The equations were deduced from the equations of Einstein in the presence of a matter energy-momentum tensor of a perfect fluid with equation of state p = (..gamma..-1) rho. It is found that the 0--0 component of the first order equations together with the gauge conditions are consistent with the Bianchi type V model, without axial symmetry. It represents a ''ground state'' situation of the Bianchi type IX model (Mixmaster model.) The second order equations, describing the reaction back of the gravitational waves on the slowly varying background, give rise to rotation and will disturb the isotropization mechanism. The numerical ...
Based on a generalized theory of perturbations and on non-linear programming an approach to the quantitative determination of necessary accuracies for nuclear data is described. It is used to calculate transactinide isotope build-up in reactors.
The perturbations of the L.R.S. class A spatially homogeneous spacetimes are treated using Hamiltonian methods in conjunction with techniques from the theory of Lie group harmonic analysis. These latter techniques lead to a simple way of handling any set of tensor equations on these background spacetimes which has the same symmetry group as the space-time metric. Once this approach is developed, the Hamiltonian formulation is used to recover in a clean way the Bonanos equations for the perturbations of the perfect fluid models of the class of spacetimes under consideration. The conserved quantities associated with the four-dimensional symmetry group are evaluated and their role in the linearized Hamiltonian dynamics is discussed. The time-dependent linear canonical transformation of the linearized vacuum gravitational phase space adapted to Moncrief's gauge invariant decomposition is described in general for these models and evaluated ...
BackgroundNeurofibromatosis type 1 (NF1) is a common monogenic tumor-predisposition disorder that arises secondary to mutations in the tumor suppressor gene NF1....Full Text Available
The liver plays a vital role in glucose homeostasis, the synthesis of bile acids and the detoxification of foreign substances. Liver culture systems are widely used to test adverse effects of drugs...Full Text Available
We examine the effect of a threshold bias on the power spectrum and the bispectrum in an ensemble of numerical simulations (Gaussian initial perturbations with power law spectra P(k) \\sim k^n, n=+1, 0, -1, -2) and compare our results with theoretical predictions. Our simulations are evolved sufficiently that on the scale where we apply the threshold the rms fluctuation has developed significantly into the nonlinear regime. Thus, predictions based on perturbation theory do not necessarily apply. Nevertheless, we find our results for the power spectrum, biased power simply amplified by a numerical factor, follow predicted trends, far beyond the regime where perturbation theory is expected to be valid. We find that the biased bispectrum continues to follow the so-called hierarchical form, with reduced three-point amplitude Q \\approx 1 in the strongly nonlinear regime, independent of initial spectrum. In the quasi-linear ...
A non-contact method, using magnetic drag force principle, was proposed to design the braking systems to improve the shortcomings of the conventional braking systems. The extensive literature detailing all aspects of the magnetic braking is briefly reviewed, however little of this refers specifically to upright magnetic braking system, which is useful for industries. One of the major issues to design upright magnetic system is to find out the magnetic flux. The changing magnetic flux induces eddy currents in the conductor. These currents dissipate energy in the conductor and generate drag force to slow down the motion. Therefore, a finite element model is developed to analyze the phenomena of magnetic flux density when air gap and materials of track are varied. The verification shows the predicted magnetic flux is within ...
Muonic-atom energy levels and wave functions are calculated. The results are corrected for nearly all important static effects, including finite nuclear size as produced by a user-specified nuclear charge distribution. Fourth-order Runge-Kutta integration of the radial Dirac equations, with the secant method determining the eigenvalues. Corrections are either included as potentials in the Dirac equations or computed as first-order perturbations. The code assumes spherical symmetry, so that effects of nuclear deformation may be treated only as static first-order perturbations. Dynamic muon-electron and muon-nuclear effects are neglected (the latter are calculated by RURP). (Auth.).
The cross sections of neutral tensor mesons T=a{sub 2}, f, f', ... production in the exclusive {gamma}{gamma}{yields}TT' or semiexclusive {gamma}{gamma}{yields}TX processes (three gluon exchange) in the semihard region s>>vertical stroketvertical stroke>1 GeV{sup 2} are calculated. The relation of investigated processes to the problem of perturbative Odderon is discussed. The possibility of measurements at LEP and at a future {gamma}{gamma}-colliders is discussed too. (orig.).
We present a recent study of the QCD corrections to dilepton production near partonic threshold in transversely polarized {bar p}p scattering, We analyze the role of the higher-order perturbative QCD corrections in terms of the available fixed-order contributions as well as of all-order soft-gluon resummations for the kinematical regime of proposed experiments at GSI-FAIR. We find that perturbative corrections are large for both unpolarized and polarized cross sections, but that the spin asymmetries are stable. The role of the far infrared region of the momentum integral in the resummed exponent and the effect of the NNLL resummation are briefly discussed.
Several recent experiments on micro- (or nano-) structured samples of ferromagnetic materials are introduced. Magnetization reversal phenomena are investigated on submicron wire samples of trilayer structure using the giant magnetoresistance effect. Domain wall movements are sensitively monitored by resistivity measurements and the velocity of propagation is determined. The contribution of domain wall to the resistivity is argued from the results on artificially designed samples of a spring-magnet system. In circular dots of permalloy, the existence of vortex magnetization is confirmed and the reversal of the vortex core magnetization is studied from magnetic force microscopy measurements. (author)
To investigate the magnetic fluctuations and for further transport study, the poloidal and radial magnetic field measurement is conducted on the Sino United Spherical Tokamak (SUNIST). Auto-power spectral density indicates that the magnetic fluctuation energy mainly concentrates in the frequency region lower than 10 kHz. The magnetic field oscillations, which are characterized by harmonic frequencies of 40 kHz, are observed in the scrape-off layer; by contrast, in the plasma core, the magnetic fluctuations are of Gaussian type. The time-frequency profiles show that the poloidal magnetic fluctuations are temporally intermittent. The autocorrelation calculation indicates that the fluctuations in decorrelation time vary between the core and the edge. (authors)
In t(15;17) acute promyelocytic leukemia, all-trans retinoic acid (RA) induces leukemic cell maturation in vitro and remission in acute promyelocytic leukemia patients, but in vivo treatments invariably...Full Text Available
Programmed cell death (PCD) is triggered when Pto, a Ser-Thr protein kinase, recognizes either the AvrPto or AvrPtoB effector from Pseudomonas syringae pv tomato. This...Full Text Available
Autophagy is a regulated catabolic process triggered in cells deprived of nutrients or growth factors that govern nutrient uptake. Here we report that autophagy is induced by cetuximab, a therapeutic...Full Text Available
Apr 16, 2007 ... with a 1-sigma error radius of about 0.5 arc sec. ... It was consistent with a single point source at: RA (J2000) = 03h 13m 57.6s ... At 13000 sec. after the trigger, the magnitude in the UVOT B filter was ~19.9 with a ...
Events detected in a shielded plastic scintillation counter occurring in the 26 microsec preceding the arrival of an extensive air shower at ground level with local electron density or = 20 m to the -2 power and the 240 microsec after its arrival have been studied. No significant excess of events (tachyons) arriving in the early time domain have been observed in a sample of 11,585 air shower triggers.
PCD (programmed cell death) in plants presents important morphological and biochemical differences compared with apoptosis in animal cells. This raises the question of whether PCD arose independently...Full Text Available
Recent observations of the evolutionary properties of paired and interacting galaxies are reviewed, with special emphasis on their global emission properties and star formation rates. Data at several wavelengths provide strong confirmation of the hypothesis, proposed originally by Larson and Tinsley, that interactions trigger global bursts of star formation in galaxies. The nature and properties of the starbursts, and their overall role in galactic evolution are also discussed.
The presynaptic Ca2+ signal, which triggers vesicle release, disperses to a broadly distributed residual [Ca2+] ([Ca2+]res) that plays an important...Full Text Available
Arsenic trioxide (As2O3), used to treat promyelocytic leukemia, triggers cell death via unknown mechanisms. To further our understanding of As2O3-induced...Full Text Available
Three-dimensional dynamics of a compact toroid (CT) plasmoid, which is injected into a magnetized target plasma region is investigated by using magnetohydrodynamic (MHD) numerical simulations. It is found that the process of the CT penetration into this region is much more complicated than what has been analyzed so far by using a conducting sphere (CS) model. The injected CT suffers from a tilting instability, which grows with the similar time scale as the CT penetration. The instability is accompanied by magnetic reconnection between the CT magnetic field and the target magnetic field, which disrupts the magnetic configuration of the CT. Magnetic reconnection plays a role to supply the high density plasma initially confined in the CT magnetic field into the target region. Also, the penetration depth of the CT high density plasma is ...
Potassium clusters arrayed in zeolite A are known to show ferromagnetic properties at low temperature. The origin of the spontaneous magnetization has been explained by a model of spin-canting in an antiferromagnetically ordered state. The direct information for the magnetic structure, however, has not been obtained so far. In the present work, we measure the neutron powder diffraction by using pulsed neutron source at KEK-KENS below and above the Curie temperature. No significant temperature-dependence was, however, obtained within the statistical errors, namely, magnetic scattering could not be detected separately. We also estimate the intensity of magnetic scattering by assuming some possible magnetic structures with considering the magnetic form factor of the cluster wave function. The intensity of magnetic scattering is estimated to be ...
Potassium clusters arrayed in zeolite A are known to show ferromagnetic properties at low temperature. The origin of the spontaneous magnetization has been explained by a model of spin-canting in an antiferromagnetically ordered state. The direct information for the magnetic structure, however, has not been obtained so far. In the present work, we measure the neutron powder diffraction by using pulsed neutron source at KEK-KENS below and above the Curie temperature. No significant temperature-dependence was, however, obtained within the statistical errors, namely, magnetic scattering could not be detected separately. We also estimate the intensity of magnetic scattering by assuming some possible magnetic structures with considering the magnetic form factor of the cluster wave function. The intensity of magnetic scattering is estimated to be ...
Scanning ion microscopy with polarization analysis (SIMPA) is used to study the spin-resolved surface magnetic structure of nano-sized magnetic systems. SIMPA is utilized for in situ topographic and spin-resolved magnetic domain imaging as well as for focused ion beam (FIB) etching of desired structures in magnetic or non-magnetic systems. Ultra-thin Co films are deposited on surfaces of Si(1 0 0) substrates, and ultra-thin, tri-layered, bct Fe(1 0 0)/Mn/bct Fe(1 0 0) wedged magnetic structures are deposited on fcc Pd(1 0 0) substrates. SIMPA experiments clearly show that ion-induced electrons emitted from magnetic surfaces exhibit non-zero electron spin polarization (ESP), whereas electrons emitted from non-magnetic surfaces such as Si and Pd exhibit zero ESP, which can be used to calibrate sputtering rates in situ. We ...
A number of interactions between magnetic fields and matter is reviewed. The resulting forces range in magnitude from the very large, obtained in high-energy fields, to the weak ones caused by the magnetostriction of ferromagnets. The fundamentals of these interactions are highlighted, and the examples discussed are forces on dipoles, particle alignment, magnetostrictive forces, magnetic forming, magnetic stirring, levitation melting, and magnetic pulsing of tool steels. (orig.)
A model is available in predicting flocculation frequencies between particles of various properties under the influence of a magnetic field. This model provides a basic understanding of fundamental phenomena, such as particle-particle and particle-collector interactions, occurring in HGMF (high gradient magnetic field), and will be extended to describe experimental data of particle flocculation and filtration and predict the performance of high- gradient magnetic filters. It is also expected that this model will eventually lead to a tool for design and optimization of magnetic filters for environmental, metallurgical, biochemical, and other applications.
The R and D activities of the institute focused on two major projects, ``Molecular and cellular environmental toxicology``, and ``Biophysics of multi-cellular systems``. For assessment of health risks emanating from the uptake of heavy metal compounds, work performed under the first mentioned project studies the formation of allergy-inducing metabolic products from membrane lipids, and the effects of related cellular signaling processes. These studies are accompanied by an approach to quantify and classify the toxicity of environmental organometallic compounds. Another major task is research into the pathogenesis of lung disease induced by dusts, gases, and gas-dust mixtures and the liberation of inflammatory agents by immunological cell reactions (alveolar macrophages). Atomic force microscopy is the tool used to visualize the related dynamic changes in bronchial cells. Studies for detection of the localisation and structure of the Fe-Mo co-factor in nitrogenase by means of the method ...
Abstract in english We present a detailed derivation of the effective dielectric constant to be used in the dispersion relation for electrostatic waves in the case of a plasma immersed in a inhomogeneous magnetic field, with inhomogeneity perpendicular to the direction of the magnetic field.
A tutorial account is given of the main characteristics and distinctive features of conceptual magnetic fusion systems employing the magnetic mirror principle. These features are related to the potential advantages that mirror-based fusion systems may exhibit for the generation of economic fusion power.
An analytic model of magnetic torques applied to an accreting neutron star is employed to evaluate the magnetic dipole moments of x-ray pulsars. A new type of close binary system containing a neutron star is suggested.
An introduction to time-of-flight neutron spectroscopy is presented in the context of the study of magnetic materials. Examples are taken from the class of rare earth and actinide magnetic materials known as `strongly correlated electron` systems. (author) 11 figs., 24 refs.
The past decade has seen the development of eddy current probes for inspection of the mildly ferro-magnetic alloy Monel 400. Due to the rapid advances in permanent magnet technology similar probes have been upgraded to magnetically saturate, and hence ins...
The disclosure is directed to an active magnetic regenerator apparatus and method. Brayton, Stirling, Ericsson, and Carnot cycles and the like may be utilized in an active magnetic regenerator to provide efficient refrigeration over relatively large temperature ranges.
Parameters of permanent magnets result from the combination of intrinsic properties such as saturation magnetization, magnetic exchange, and magnetocrystalline energy, as well as microstructural parameters such as phase structure, grain size, and orientation. Reduction of grain size into nanocrystalline regime (#approx# 50 nm) leads to the enhanced remanence which derives from ferromagnetic exchange coupling between highly refined grains. In this study the fundamental phenomena, quantities, and structure parameters, which define nanophase permanent magnets are presented and discussed. The theoretical considerations are confronted with experimental data for nanocrystalline Sm-Fe-N type permanent magnets. (author)
Principle advantages of magnetic forming for part manufacture appear to lie ... to be an area of great potential for the magnetic forming process. We have a ...
OBJECTIVE--The study was performed to examine the influence of the exposure to magnetic fields in the potrooms of an electrolysis plant on the occurrence of musculoskeletal symptoms among the employees....Full Text Available
Several refrigerators for liquid helium and liquid nitrogen systems have been integrated successfully into IGC manufactured whole body Magnetic Resonance Imaging (MRI) magnet systems. The refrigerators have been tested in systems with magnetic fields of 0.6T to 1.5T. Tests were performed to study the effectiveness of the refrigerators, the magnetic field effects on the refrigerators, the effect of the refrigerators on the field uniformity and magnetic resonance image quality. The interface between the refrigerator and the whole body MRI magnet system cryostat was specifically designed to allow retrofit to the existing IGC magnet systems, while ensuring good heat transfer characteristics and good vibration isolation from the cryostat. The interface between the refrigerator and the cryostat and the refrigerator test results are presented.
The Muon Ionization Cooling Experiment (MICE) focusing solenoid magnets focus the muon beam within the MICE cooling channel on a liquid or solid absorber that is within the warm bore of solenoid. The focusing magnet has a warm bore of 470 mm. his magnet consists of two coils 210-mm long that is separated by an aluminum mandrel that is 200 mm long. Each of the coils has its own leads. The coils may be operated in either the non-flip mode (solenoid mode with both coils at the same polarity) or the lip mode (quadrupole focusing mode where both coils are at opposite polarity). This report describes the focusing solenoid magnet design that will be built by the vendor. The progress on the construction of the first of the focusing magnets will also be discussed in this report. Ultimately three of these magnets will be built. These magnets will be ...
The ternary rare earth compound NdRh_4B_4 has been studied by means of critical field, low temperature heat capacity, and static magnetic susceptibility measurements. Features in the upper critical field and heat capacity data at 1.31 K and 0.89 K suggest the occurrence of long-range magnetic order in the superconducting state. The temperature dependence of the static magnetic susceptibility follows a Curie-Weiss law with an effective magnetic moment #mu#sub(eff) = 3.58 +- 0.05 #mu#sub(B) and a Curie-Weiss temperature thetasub(p) = -6.2 +- 1.0 K between 20 K and room temperature. However, magnetization vs. applied magnetic field isotherms suggest the development of a ferromagnetic component in the Nd"3"+ magnetization at low temperatures. (author).
Highly ordered arrays of Ni nanoholes and Fe{sub 20}Ni{sub 80} antidots have been prepared, respectively, by replica/antireplica processing and sputtering techniques using nanoporous alumina membranes as templates. Geometrical characteristics as nanohole/antidot diameter, interpore distance and the overall hexagonal symmetry of arrays are controlled through the original templates. Experimental data on their hysteresis and magnetic domain structure have been taken by vibrating sample magnetometry and magnetic force microscopy, respectively. An analysis of the magnetization process, resulting magnetic anisotropy and magnetic domain structure is summarized considering the influence of those geometry aspects. In particular, the hexagonal symmetry and the density of nanohole/antidots determine the overall magnetic behavior, which is of interest in future high-density ...
Highly ordered arrays of Ni nanoholes and Fe20Ni80 antidots have been prepared, respectively, by replica/antireplica processing and sputtering techniques using nanoporous alumina membranes as templates. Geometrical characteristics as nanohole/antidot diameter, interpore distance and the overall hexagonal symmetry of arrays are controlled through the original templates. Experimental data on their hysteresis and magnetic domain structure have been taken by vibrating sample magnetometry and magnetic force microscopy, respectively. An analysis of the magnetization process, resulting magnetic anisotropy and magnetic domain structure is summarized considering the influence of those geometry aspects. In particular, the hexagonal symmetry and the density of nanohole/antidots determine the overall magnetic behavior, which is of interest in future high-density ...
It is shown that plasma viscosity does not influence the magnetic island rotation directly. Nevertheless, it leads to nonstationarity of the plasma velocity. This nonstationarity is the reason of the viscosity effect on island rotation. (author)
... M(TH) in applied magnetic fields up to ± 7 T and for temperatures ranging from 2 to 300 K. The superparamagnetic (SPM) behavior of these metallic ...
Effective localization of small magnets against a noisy, real world background can involve various methods to first identify the magnetic fields produced by the magnet of interest, then to filter out background noise, and then to analyze the available magnetic field data to localize the magnet. Here we discuss low cost techniques which allow localization of small magnets with field strengths in the milliGauss range against real world background fields in the range of hundreds of mG, which may be fluctuating by up to tens of mG. Such techniques allow magnet tracking to be used to localize catheters in place of more invasive and expensive methods, e.g. fluoroscopy, for a variety of applications, including drug infusion with peripherally inserted central catheters (PICCs), laser ablation (TMR, PTMR) and introduction of pacemaker leads.
Development of Portable Normobaric Hypoxia and Pulsed Magnetic Field Firmware System for Enhancement of Radio- and Non-specific Resistance in Workers of Environmentally Hazardous Industries
The dynamic response of cylindrical and ring-shaped YBaCuO bulk parts to pulsed magnetic fields is calculated by using small sets of finite elements. Some comparisons with experimental results are provided, and they give confidence in the modelling of the superconducting properties. Transient magnetizations as a function of time and space as well as shapes and absolute values of trapped magnetic flux profiles are presented. The influence of the sample geometry is investigated for different millisecond pulsed magnetization processes. Results are reported for different radial thicknesses and heights, different pulse durations, peak magnetic fields and pulse sequences with and without stepwise cooling. Comparisons concerning the achievable trapped magnetic field and flux are made, and implications for the use of high-temperature superconductor bulk parts as ...
A nanosuspension of magnetically tagged metronidazole was developed by the solvent displacement method coupled with ultrasonication and was evaluated for its physicochemical properties. The drug release from metronidazole magnetic nanosuspension at pH 1.2 and 7.0 shows maximum correlation coefficient for zero order and Higuchi model, respectively. The anthelmintic activity of the formulated metronidazole magnetic nanosuspension was evaluated on Indian earthworms (Pheretima poi). Metronidazole magnetic nanosuspension at a dose of 10 and 50 mg/ml shortened by 31% and 34%, respectively, the mean time to death of the earthworms when compared against a non-magnetic metronidazole suspension. Thus, the developed metronidazole magnetic nanosuspension showed potent, controlled and targeted drug action and might be a good therapeutic avenue in combating infectious GI ...
With the increased costs of maintaining boilers and chillers entrepreneurs around the country have offered magnetic and similar devices to facilities as viable alternatives to their maintenance program. This report gives a brief history of some of the pre...
... design, and manufacturing knowledge have been acquired and used to develop an 'in-house' capability for the fabrication of magnetic forming coils ...
has been generally related to magnetic forming. One of the methods suggested was the following: A "pancake" magnetic coil is placed over a thin aluminum ...
From optical point of view and due to the magnetic interaction of the cold neutrons with the unpaired electron shell, magnetic materials hae a neutron spin-dependent refractive index n[sup +] [spin up] and n[sup -] [spin down]. Magnetic media such as Fe, Co and Ni react like birefringent uniaxial crystals in ordinary optica. n[sup +] and n[sup -] are the equivalent of the ordinary and extraordinary refractive indices. The specular reflection of spin polarized neutrons which is due to the discontinuity of the magnetic induction at the surface of the ferromagnet is a sensitive probe of surface and interface magnetism. We shall first give the background of the art of polarized neutron optics. Secondly, some recent examples from surface and interface magnetism will be given to illustrate the power of this technique such as the magnetic coupling ...
For the purpose of solving the limitations such as shape and dimension for magnetic compact fabricated by conventional anisotropic forming under magnetic orienting field, the feasibility of a new magnetic forming process was studied. Ferrite powder mixed with UV resin was compacted in the die mold and followed by alignment under the magnetic field. Effects of viscosity of UV resin and forming condition on magnetic characteristics of the compact was investigated. Maximum degree of alignment for the ferrite powder reached to 0.826. It was predicted that the proposed method had make it possible to fabricate a high performance magnet having the anisotropic alignment of the magnetic powder. The UV resin is desirable to have low viscosity, good properties such as formability and configuration stability for the compact and also parting- ability ...
magnet research at several national laboratories through its Advanced Accelerator Technology Program. The HEP Conductor Development Program, a collaboration among national...
The magnetic properties of a single crystal of SmNiSn with the orthorhombic {epsilon}-TiNiSi-type crystal structure have been investigated by magnetic susceptibility, magnetization and electrical resistivity measurements from 1.5 K to room temperature. Two anomalies have been found in the magnetic susceptibility, indicating an antiferromagnetic phase transition at T{sub N}=9.4 K and a second transition at 4.4 K. A large magnetic anisotropy has been found at low temperatures in the temperature and field dependencies of magnetic susceptibility and magnetization. Below 80 K, the easy axis of the magnetization is the c-axis. At T=2.0 K, the c-axis magnetization curve exhibits metamagnetic-like behavior at H{sub c}=42 kOe and reaches 0.54 emu/g at H=55 kOe, whereas for the a- and b-axis the ...
A study on development of magnetic drive packless valves for commercial purpose showed the results as follows; 1. Study on the radial rays effecting to the permanent magnets -Measurement of the strength of Nd-magnets according to irradiation of radial rays. 2. Effects of temperature on the magnetic driving device -Temperature dependency of the Nd-casting magnets. -Effects of temperature on the heat releasing fins of high-temperature valve. 3. Optimization of torque -Arranging method of permanent magnets -Measuring method and results of torque. 4. Design, manufacture and test for the pressure-resisting structure of magnetic power transmitting device -Calculation and design for the flat circular plates under pressure of the magnetic power transmitting device -Design, manufacture and test for the pressure-resisting ...
180 deg magnet chamber is used in Folded Tandem Ion Accelerator for passage and 180 deg bending of ion beam. The chamber is placed between 180 deg terminal magnet (Electro-magnet), which is used for bending, and analysing the beams. Magnet with a particular magnetic field strength bends ions of only specified mass energy product through a precise path. There is also a space limitation in the direction of magnetic field. Both of them require the magnet chamber to be of a close tolerance. Accuracy of center distance between inlet and outlet port of the magnet chamber has to be at par with the concentricity of high energy and low energy beam line. To achieve this we started the fabrication of magnet chamber by following two methods: a) Circular rolling and bending of rectangular tube for 180 deg sector ...
Tests have recently been performed at Fermilab in order to measure the energy losses due to eddy currents and iron and superconductor magnetization. These measurements were performed on six 1.5m long model magnets and eight 15m long full scale collider dipole magnets. AC losses were measured as a function of ramp rate using sawtooth ramps from 500, to 5000 Amps for both types of magnets, while bipolar studies were additionally performed on some of the short magnets. The measured magnet voltage and current for a complete cycle are digitally integrated to yield the energy loss per cycle. Measurement reproducibility is typically 5%, with good agreement between long magnet measurements and extrapolations from short magnet measurement results. Magnetization loss measurements among similar ...
The relative contributions of interstitials and vacancies to diffusion of a dopant A in silicon are specified by the interstitial fraction of diffusivity, f{sub A}. Accurate knowledge of f{sub A} is required for predictive simulations of Si processing during which the point defect population is perturbed, such as transient enhanced diffusion. While experimental determination of f{sub A} is traditionally based on an underdetermined system of equations, we show here that it is actually possible to derive expressions that give meaningful bounds on f{sub A} without any further assumptions but that of local equilibrium. By employing a pair of dopants under the same point-defect perturbance, and by utilizing perturbances very far from equilibrium, we obtain experimentally f{sub Sb}{le}0.012 and f{sub B}{ge}0.98 at temperatures of {approximately}800{degree}C, which are the strictest bounds reported to date. Our results are in ...
The relative contributions of interstitials and vacancies to diffusion of a dopant A in silicon are specified by the interstitial fraction of diffusivity, f_A. Accurate knowledge of f_A is required for predictive simulations of Si processing during which the point defect population is perturbed, such as transient enhanced diffusion. While experimental determination of f_A is traditionally based on an underdetermined system of equations, we show here that it is actually possible to derive expressions that give meaningful bounds on f_A without any further assumptions but that of local equilibrium. By employing a pair of dopants under the same point-defect perturbance, and by utilizing perturbances very far from equilibrium, we obtain experimentally f_S_b#<=#0.012 and f_B#>=#0.98 at temperatures of #approx#800 degree C, which are the strictest bounds reported to date. Our results are in agreement with a theoretical ...
An experimental campaign, aiming to investigate the perturbation effects induced by fixed obstacles on turbulence measurements in airflows at the air-sea interface, was carried out at the marine platform of the Italian Navy, located in the harbour of La Spezia (North Ligurian Sea, Italy) on 28., 29., and 30. June 1994. This study was prompted by the ever-growing interest in more reliable estimates of energy, mass, and momentum exchanges between water surfaces and atmosphere, whose measurements are severely limited by the geometrical constraints of floating or fixed platforms where they are installed. Two types of meteorological instruments have been used: fast response (20 and 21 Hz) ultrasonic anemometers and fluxmeters to measure turbulent momentum, sensible, and latent heat fluxes and slow-response sensors (less than 4 Hz and sampled at a rate of 10{sup 2} Hz) to measure average wind and temperature vertical profiles in the perturbed ...
Three-flavor lattice QCD simulations and two-loop perturbation theory are used to make the most precise determination to date of the strange-, up-, and down-quark masses, $m_s$, $m_u$, and $m_d$, respectively. Perturbative matching is required in order to connect the lattice-regularized bare- quark masses to the masses as defined in the \\msbar scheme, and this is done here for the first time at next-to-next-to leading (or two-loop) order. The bare-quark masses required as input come from simulations by the MILC collaboration of a highly-efficient formalism (using so-called ``staggered'' quarks), with three flavors of light quarks in the Dirac sea; these simulations were previously analyzed in a joint study by the HPQCD and MILC collaborations, using degenerate $u$ and $d$ quarks, with masses as low as $m_s/8$, and two values of the lattice spacing, with chiral extrapolation/interpolation to the physical masses. With the new ...
The WIDeField telescope for Gamma-ray burst Early Timing (WIDGET) is used for a fully automated, ultra-wide-field survey aimed at detecting the prompt optical emission associated with Gamma-ray Bursts (GRBs). WIDGET surveys the HETE-2 and Swift/BAT pointing directions covering a total field of view of 62 degree x 62 degree every 10 secounds using an unfiltered system. This monitoring survey allows exploration of the optical emission before the gamma-ray trigger. The unfiltered magnitude is well converted to the SDSS r' system at a 0.1 mag level. Since 2004, WIDGET has made a total of ten simultaneous and one pre-trigger GRB observations. The efficiency of synchronized observation with HETE-2 is four times better than that of Swift. There has been no bright optical emission similar to that from GRB 080319B. The statistical analysis implies that GRB080319B is a rare event. This paper summarizes the design and operation of the WIDGET system and ...
Semiconductor quantum dots (QDs) are a promising approach to realize a single-photon source. To avoid bulky and expensive laser systems for future applications, electrical excitation is desirable. InP QDs are especially suited, as they emit in the red spectral range and therefore in the optimal range of commercial detectors. Additionally, they have been shown to be capable of emitting single photons up to 80 K. Thus, we embedded InP QDs in the intrinsic region of a p-i-n diode. To form single devices, 100 #mu#m mesas were etched and supplied with electrical contacts. We investigated the electroluminescence from single QDs and performed second-order auto correlation measurements to verify single-photon emission. To prevent expensive helium cooling and reach operation above 80 K, we investigated the influence of elevated temperature on the performance of our device. Since triggered single-photon emission is required for most applications, sub-nanosecond pulses were ...
The presented results are the first measurements at RHIC for direct $\\gamma$-charged hadron azimuthal correlations in heavy ion collisions. We use these correlations to study the color charge density of the medium through the medium-induced modification of high-p$_T$ parton fragmentation. Azimuthal correlations of direct photons at high transverse energy (8 $<$ p$_T$ $<$ 16 GeV) with away-side charged hadrons of transverse momentum (3 $<$ p$_T$ $<$ 6 GeV/c) have been measured over a broad range of centrality for $Au+Au$ collisions and $p+p$ collisions at $\\sqrt{s_{NN}}$ = 200 GeV in the STAR experiment. A transverse shower shape analysis in the STAR Barrel Electromagnetic Calorimeter Shower Maximum Detector is used to discriminate between the direct photons and photons from the decays of high p$_T$ $\\pi^{0}$. The per-trigger away-side yield of direct $\\gamma$ is smaller than from $\\pi^{0}$ trigger at the same centrality class. ...
A total of 10 samples disks of 2024-T3 aluminum and 4130 ferrous steel were exposed to rocket-triggered lightning currents at the Kennedy Space Center test site in Florida during the summer of 1990. The experimental configuration was arranged so that the samples were not exposed to the preliminary streamer, wire-burn, or following currents that are associated with an upward-initiated rocket-triggered flash but which are a typical of naturally initiated lightning. Return-stroke currents and continuing currents actually attaching to the sample were measured, augmented by close-up video recordings of approximately 3 feet of the channel above the sample and by 16-mm movies with 5-ms resolution. From these data it was possible to correlate individual damage spots with streamer, return-stroke, and continuing currents that produced them. Substantial penetration of 80-mil aluminum was produced by a continuing current of submedian amplitude and ...
The theory of ..cap alpha.. decay in first-order perturbation theory is presented. The theory is designed for a strongly deformed nucleus in an isomeric state which changes its deformation dynamically through decay from a very deformed to an almost spherical shape. It is shown that other channels are not coupled to the ..cap alpha.. channel in first-order perturbation theory. The collective degrees of freedom of the daughter nucleus are described by shape vibrational states, eigenstates of a Hamiltonian whose potential has two minima. The parent nucleus is described by dynamically coupling the vibrational degrees of freedom to the ..cap alpha..-particle motion and also taking rotations into account. The ..cap alpha.. particle is taken to be a point-like particle. The theory is applied to the ..cap alpha.. decay of the isomeric state of /sub 95//sup 242/Am.
We study analytically and numerically the stability of the pressure-less, viscously spreading accretion ring. We show that the ring is unstable to small non-axisymmetric perturbations. To perform the perturbation analysis of the ring we use a stretching transformation of the time coordinate. We find that to 1st order, one-armed spiral structures, and to 2nd order additionally two-armed spiral features may appear. Furthermore, we identify a dispersion relation determining the instability of the ring. The theoretical results are confirmed in several simulations, using two different numerical methods. These computations prove independently the existence of a secular spiral instability driven by viscosity, which evolves into persisting leading and trailing spiral waves. Our results settle the question whether the spiral structures found in earlier simulations of the spreading ring are numerical artifacts or genuine instabilities.
The propagation of acoustic pressure perturbations in an adiabatic low-quality air/water flow were investigated both theoretically and experimentally. A linearized dispersion model is correlated with data to extract information on the behavior of interfacial momentum transfer controlled by the virtual volume coefficient. The dispersion model is examined in limiting cases of low and high frequency and related to current models for critical flow velocity. Fourier decomposition techniques are employed to predict the dispersion of measured pressure pulses and to relate data for standing waves and propagating pulses. The dispersion model is based on a two-fluid model and is the most complete model available in the literature at this time. The dispersion data presented herein is also the best available to date for low frequency (i.e., frequencies less than bubble resonance) sound propagation in bubbly air/water mixtures.
The reaction {gamma}d{yields}{pi}{sup +}nn is calculated up to order {chi}{sup 5/2} in chiral perturbation theory, where {chi} denotes the ratio of the pion to the nucleon mass. Special emphasis is put on the role of nucleon recoil corrections that are the source of contributions with fractional power in {chi}. Using the known near-threshold production amplitude for {gamma}p{yields}{pi}{sup +}n as the only input, the total cross-section for {gamma}d{yields}{pi}{sup +}nn is described very well. A conservative estimate suggests that the theoretical uncertainty for the transition operator amounts to 3% for the computed amplitude near threshold. (orig.)
Algorithms for generating new exact solutions of the Einstein-Klein-Gordon field equations, which describe inhomogeneous universes with S/sup 3/ topology of spatial sections, are developed. The known exact vacuum and still-fluid solutions with S/sup 3/ topology are used as an input. The methods developed are further applied to derive inhomogeneous generalizations of Bianchi type IX solutions and inhomogeneous S/sup 3/ Gowdy models with gravitational and scalar waves. It is shown that the new solutions, which are generalizations of the Bianchi type IX models, permit identification of the scalar field with the velocity potential of the stiff irrotational fluid. The latter result is further used to study the growth rate of density perturbations of the isotropic and anisotropic Bianchi type IX universes in a fully nonlinear relativistic regime. The role of anisotropy on the rate of growth of density perturbations is studied in detail.
Algorithms for generating new exact solutions of the Einstein-Klein-Gordon field equations, which describe inhomogeneous universes with S"3 topology of spatial sections, are developed. The known exact vacuum and still-fluid solutions with S"3 topology are used as an input. The methods developed are further applied to derive inhomogeneous generalizations of Bianchi type IX solutions and inhomogeneous S"3 Gowdy models with gravitational and scalar waves. It is shown that the new solutions, which are generalizations of the Bianchi type IX models, permit identification of the scalar field with the velocity potential of the stiff irrotational fluid. The latter result is further used to study the growth rate of density perturbations of the isotropic and anisotropic Bianchi type IX universes in a fully nonlinear relativistic regime. The role of anisotropy on the rate of growth of density perturbations is studied in detail.
In order to develop a numerical tool for the fast evaluation of CANDU refuelling schemes, a Linear Sensitivity Matrix method (LSM) is developed. It assumes that all the effects caused by various perturbations to the core state are independent to each other and the core response to a perturbation is proportional to its magnitude. In this way, the main core parameters of a refuelling scheme can be derived by simple algebraic operations with the use of pre-calculated sensitivity matrices, without resorting to the complicated and time-consuming 3D core calculation. Verification against the Qinshan CANDU reactor operation history demonstrates that LSM is capable of generating accurate results and running very fast for evaluating a refuelling scheme. (authors)
Neutron stars are sensitive laboratories for testing general relativity, especially when considering deviations where velocities are relativistic and gravitational fields are strong. One such deviation is described by dynamical, Chern-Simons modified gravity, where the Einstein-Hilbert action is modified through the addition of the gravitational parity-violating Pontryagin density coupled to a field. This four-dimensional effective theory arises naturally both in perturbative and non-perturbative string theory, loop quantum gravity, and generic effective field theory expansions. We calculate here Chern-Simons modifications to the properties and gravitational fields of slowly spinning neutron stars. We find that the Chern-Simons correction affects only the gravitomagnetic sector of the metric to leading order, thus introducing modifications to the moment of inertia but not to the mass-radius relation. We show that an observational determination ...
A fully consistent linear perturbation theory for cosmology is derived in the presence of quantum corrections as they are suggested by properties of inverse volume operators in loop quantum gravity. The underlying constraints present a consistent deformation of the classical system, which shows that the discreteness in loop quantum gravity can be implemented in effective equations without spoiling space-time covariance. Nevertheless, non-trivial quantum corrections do arise in the constraint algebra. Since correction terms must appear in tightly controlled forms to avoid anomalies, detailed insights for the correct implementation of constraint operators can be gained. The procedures of this article thus provide a clear link between fundamental quantum gravity and phenomenology.
The Data Acquisition System for the CDMS II dark matter experiment was designed and built when the experiment moved to its new underground installation at the Soudan Lab. The combination of remote operation and increased data load necessitated a completely new design. Elements of the original LabView system remained as stand-alone diagnostic programs, but the main data processing moved to a VME-based system with custom electronics for signal conditioning, trigger formation and buffering. The data rate was increased 100-fold and the automated cryogenic system was linked to the data acquisition. A modular server framework with associated user interfaces was implemented in Java to allow control and monitoring of the entire experiment remotely.
It is postulated that a break of a thin-walled pipe does not cause a subsequent break in the pipe in the vicinity of a plastic hinge even when the wall is weakened by a 60 circumferential crack of a depth of 30% of the wall thickness on the tension side. This pipe behavior is the result of plastic buckling in the compression side and applies to pipes of diameter-to-thickness ratio larger than 20. For this type of pipe, the axial strains decrease with increasing diameter-to-thickness ratio in the tension side. As the pipe is only loaded in one direction, there is no cyclic behavior that can trigger a subsequent break. (orig.)
Major similarities between robustness assessment and seismic design exist, and significant information can be brought from seismic design to robustness design. As will be discussed, although some methods and limitations considered in seismic design can improve robustness, the capacity of the structure to sustain limited damage without disproportionate effects is significantly more complex. In fact, seismic design can either improve or reduce the resistance of structures to unforeseeable events, depending on the structural type, triggering event, structural material, among others. Based on a case study, the influence of redundancy and ductility on the seismic behavior and robustness of a long-span timber structure is assessed.
We demonstrate reversible movement of (1/2)[110](110) dislocation loops generated from nanodisturbances in a #beta#-titanium alloy. High resolution transmission electron microscope observations during an in situ tensile test found three reversible deformation mechanisms, nanodisturbances, dislocation loops and martensitic transformation, that are triggered in turn with increasing applied stress. All three mechanisms contribute to the nonlinear elasticity of the alloy. The experiments also revealed the evolution of the dislocation loops to disclination dipoles that cause severe local lattice rotations.
Generalized dynamic motion of balls and cage in a ball bearing are simulated by solving the differential equations of motion under prescribed operating conditions and bearing geometry. The general cage motion is parametrically evaluated as a function of clearances both in the ball pockets and at the guide lands. The design significance of the modeling approach is demonstrated by the prediction of critical clearances which trigger certain instabilities in the cage motion. In more practical terms, the correlation between cage clearances and instability defines a wear life for the bearing under the prescribed operating conditions. 10 refs.
Visceral hypersensitivity is currently considered a key pathophysiological mechanism involved in pain perception in large subgroups of patients with functional gastrointestinal disorders, including irritable bowel syndrome (IBS). In IBS, visceral hypersensitivity has been described in 20%?90% of patients. The contribution of the central nervous system and psychological factors to visceral hypersensitivity in patients with IBS may be significant, although still debated. Peripheral factors have gained increasing attention following the recognition that infectious enteritis may trigger the development of persistent IBS symptoms, and the identification of mucosal immune, neural, endocrine, microbiological, and intestinal permeability abnormalities. Growing evidence suggests that these factors ...
This digest paper presents the theoretical project of a fission engine for space ship as imagined by Y. Ronen from the Ben-Gourion Univ. (Israel). In this engine, the combustion chamber is covered with metastable {sup 242}Am thin sheets. The fission reaction is triggered with a bombardment of neutrons and the fission fragments ionize a gas (hydrogen, for instance) which is overheated and ejected through the engine nozzle. (J.S.)
This paper describes the design of PMT readout module for detector prototype of Daya Bay Reactor Neutrino Experiment. According to the design requirements of the readout module, the basic structure of the readout module is discussed. This paper also discusses how to realize the charge measurement and time measurement and data processing using a high performance FPGA. The DAQ system including three readout modules and one trigger module are well commissioned and doing data taking now. (authors)
We entertain the idea that a suitable background of cold (very low momentum) pseudoscalar particles or condensate, may trigger a background that effectively generates Lorentz-invariance violation. This aether-like background induces a Chern-Simons modification of QED. Physics is different in different frames and, in the rest frame of the pseudoscalar background, high momentum photons can decay into pairs. The threshold for such decay depends quadratically on the rest mass of the particles. This mechanism could explain in a natural way why antiprotons are absent in recent cosmic ray measurements. A similar signal could be used as a probe of pseudoscalar condensation in heavy ion collisions.
Three different magnetic regimes; aerial, surface and buried; each with three different forces, have been used to investigate their effects on the water contents and photosynthetic pigments of sweet basil plants (Ocimum basilicum L.). Two groups of sweet basil seeds, Ocimum basilicum L. have been cultivated, one under normal conditions and the second has been subdivided into three portion (aerial, surface and buried) to examine the effect of different magnetic forces coming from the three directions on the resulted plants. At all directions of magnets, water contents have been significantly affected by the magnetic forces. Chlorophyll A and carotene contents have been affected, as well, according to the three magnetic forces coming from soil surface regime only. Chlorophyll B did not significantly affected by differences magnetic forces in the three regimes, but ...
The effects of a moderate-intensity static magnetic field (SMF) on osteoporosis of the lumbar vertebrae were studied in ovariectomized rats. A small disc magnet (maximum magnetic flux density 180 mT)...Full Text Available
Using the full potential linearized augmented plane wave (FLAPW) method, thickness dependent magnetic anisotropy of ultrathin FeCo alloy films in the range of 1 monolayer (ML) to 5 ML coverage on Pd(0 0 1) surface has been explored. We have found that the FeCo alloy films have close to half metallic state and well-known surface enhancement in thin film magnetism is observed in Fe atom, whereas the Co has rather stable magnetic moment. However, the largest magnetic moment in Fe and Co is found at 1 ML thickness. Interestingly, it has been observed that the interface magnetic moments of Fe and Co are almost the same as those of surface elements. The similar trend exists in orbital magnetic moment. This indicates that the strong hybridization between interface FeCo alloy and Pd gives rise to the large magnetic moment. Theoretically calculated ...
In the present paper the progress of optimization of soft magnetic properties have been studied by applying different experimental techniques (magnetic measurements, electric measurements, X-ray analysis, and high-resolution electron microscopy observation). It has been shown that an increase in magnetic permeability after optimization annealing can be mainly attributed to annealing out of microvoids. (author)
Neutron scattering techniques have been used to measure the static structure and magnetic excitations in amorphous magnets. Sum rules and computer models are used to discuss the relationship between the static disorder and the shape of the excitation spectrum. Polarized beam measurements of chi''(Q,E) are compared to analytical theories and computer calculations for the magnetic excitations in amorphous ferromagnets.
The MOS-technology allows to make tiny electronic lenses for multibeam electron systems. In the paper results of research and principles of designing of tiny magnetic electron lenses are submitted. Electronic lenses with a nonconventional configuration of tiny magnetic circuit and electronic lenses with coincident electric and magnetic fields in nonconventional tiny performance are considered
The influence of rigid-body and differential rotation and of a fine-scale chaotic magnetic field and a poloidal magnetic field on the minimum mass of a main-sequence star is investigated. It is shown that rotation and a magnetic field with an energy equal to 10--20% of the star's gravitational energy increase the minimum mass of a main-sequence star by 1.5--2 times.
Helical dipole magnets are required in a project for the Relativistic Heavy Ion Collider (RHIC) to control and preserve the beam polarization in order to allow the collision of polarized proton beams. Specifications are for low current superconducting magnets with a 100 mm coil aperture and a 4 Tesla field in which the field rotates 360 degrees over a distance of 2.4 meters. A magnet meeting the requirements has been developed that uses a small diameter cable wound into helical grooves machined into a thick-walled aluminum cylinder.
This paper describes a reactor design to facilitate a room-temperature nuclear fusion/fission reaction to generate heat without generating unwanted neutrons, gamma rays, tritium, or other radioactive products. The room-temperature fusion/fission reaction involves the sequential triggering of billions of single-molecule, "6LiD 'fusion energy pellets' distributed in lattices of a palladium ion accumulator that also acts as a catalyst to produce the molecules of "6LiD from a solution comprising D_2O, "6LiOD with D_2 gas bubbling through it. The D_2 gas is the source of the negative deuterium ions in the "6LiD molecules. The next step is to trigger a first nuclear fusion/fission reaction of some of the "6LiD molecules, according to the well-known nuclear reaction: "6Li + D #-># 2"4He + 22.4 MeV. The highly energetic alpha particles ("4He nuclei) generated by this nuclear reaction within the palladium will cause shock and vibrations in the ...
We have previously shown that budded viruses of Bombyx mori nucleopolyhedrovirus (BmNPV) enter the cell cytoplasm but do not migrate into the nuclei of non-permissive Sf9 cells that support a high titer of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) multiplication. Here we show, using the syncytium formation assay, that low-pH-triggered membrane fusion of BmNPV GP64 protein (Bm-GP64) is significantly lower than that of AcMNPV GP64 protein (Ac-GP64). Mutational analyses of GP64 proteins revealed that a single amino acid substitution between Ac-GP64 H155 and Bm-GP64 Y153 can have significant positive or negative effects on membrane fusion activity. Studies using bacmid-based GP64 recombinant AcMNPV harboring point-mutated ac-gp64 and bm-gp64 genes showed that Ac-GP64 H155Y and Bm-GP64 Y153H substitutions decreased and increased, respectively, the multiplication and cell-to-cell spread of progeny viruses. These results indicate that Ac-GP64 H155 ...
The compound GdPd{sub 2}Si, which is reported to order antiferromagnetically at 13 K, has been investigated by heat capacity and electrical resistivity measurement in the presence of external magnetic fields. In contrast to an earlier report, the zero-field heat capacity and resistivity data indicate two magnetic transitions at 13 and 17 K. The external magnetic field substantially influences the resistivity and heat capacity of the compound around the magnetic ordering temperature. The magnetocaloric effect, which is calculated from in-field heat capacity data, is quite large around the magnetic transition temperature. The magnetoresistance is also large near the magnetic ordering temperature. The metamagnetic transition is observed for 10 kOe magnetic field both in magnetocaloric and in magnetoresistance data. The metamagnetic transition ...
The compound GdPd_2Si, which is reported to order antiferromagnetically at 13 K, has been investigated by heat capacity and electrical resistivity measurement in the presence of external magnetic fields. In contrast to an earlier report, the zero-field heat capacity and resistivity data indicate two magnetic transitions at 13 and 17 K. The external magnetic field substantially influences the resistivity and heat capacity of the compound around the magnetic ordering temperature. The magnetocaloric effect, which is calculated from in-field heat capacity data, is quite large around the magnetic transition temperature. The magnetoresistance is also large near the magnetic ordering temperature. The metamagnetic transition is observed for 10 kOe magnetic field both in magnetocaloric and in magnetoresistance data. The metamagnetic transition ...
This paper reports that only a few years ago superconducting magnetic separation was viewed as the next major market for superconducting magnets. The first commercial units had been installed, worked flawlessly, and demonstrated real economic viability. The potential market was seen as quite large, and many people believed that superconducting magnetic separation would soon show the same rapid growth that MRI had demonstrated after its initial success. These hopes even prompted IGC, one of the top MRI magnet builders, to form a separate division devoted to magnetic separation. Despite the existence of Magstream, IGC has not been overly active in the market. As a technology that has applications from the clay on the Earth to the soil on the moon, superconducting magnetic separation has yet to become widely used.
The characteristics of the local magnetic shear, a quantity associated with high-mode-number ballooning mode stability, are considered in heliotron/torsatron devices that have a large Shafranov shift. The local magnetic shear is shown to vanish even in the stellarator-like region in which the global magnetic shear is positive. The reason for this is that the degree of the local compression of the poloidal magnetic field on the outer side of the torus, which maintains the toroidal force balance, is reduced in the stellarator-like region of global magnetic shear because the global rotational transform in heliotron/torsatron systems is a radially increasing function. This vanishing of the local magnetic shear is a universal property in heliotron/torsatron systems with a large Shafranov shift since it results from toroidal force balance in the stellarator-like ...
We have analyzed the MHD flow of a conducting couple stress fluid in a slit channel with rhythmically contracting walls. In this analysis we are taking into account the induced magnetic field. Analytical expressions for the stream function, the magnetic force function, the axial pressure gradient, the axial induced magnetic field and the distribution of the current density across the channel are obtained using long wavelength approximation. The results for the pressure rise, the frictional force per wave length, the axial induced magnetic field and distribution of the current density across the channel have been computed numerically and the results were studied for various values of the physical parameters of interest, such as the couple stress parameter ?, the Hartmann number M, the magnetic Reynolds number R and the time averaged mean flow rate ?. Contour plots for the stream and ...
This research deals with in the study of the use of innovating magnetic sensors in eddy current non destructive inspection. The author reports an analysis survey of magnetic sensor performances. This survey enables the selection of magnetic sensor technologies used in non destructive inspection. He presents the state-of-the-art of eddy current probes exploiting the qualities of innovating magnetic sensors, and describes the methods enabling the use of these magnetic sensors in non destructive testing. Two main applications of innovating magnetic sensors are identified: the detection of very small defects by means of magneto-resistive sensors, and the detection of deep defects by means of giant magneto-impedances. Based on the use of modelling, optimization, signal processing tools, probes are manufactured for these both applications.
We compare experimental data for temperature dependence of the magnetic order parameter and the magnetic excitations (spin waves) in materials with a quenched orbital moment and a well-defined spin quantum number. It is observed that the thermal decrease of the two quantities proceeds according to the same analytical function of the type y(T)=1-cT"#epsilon# with an identical exponent #epsilon#. This power function applies not only asymptotically for T->0 but holds over a wide temperature range. The exponent #epsilon# is universal, i.e. independent of spin order type and lattice symmetry and depends only on the dimensionality of the relevant interactions and on whether the spin quantum number is integer or half-integer. The different T"#epsilon# functions are identified as representations of stable universality classes. The fact that order parameter and magnetic excitations follow the same T"#epsilon# function shows that ...
We describe a class of organic molecular magnets based on zwitterionic molecules (betaine derivatives) possessing donor, p bridge, and acceptor groups. Using extensive electronic structure calculations we show the electronic ground-state in these systems is magnetic. In addition, we show that the large energy differences computed for the various magnetic states indicate a high Neel temperature. The quantum mechanical nature of the magnetic properties originates from the conjugated p bridge (only p electrons) in cooperation with the molecular donor-acceptor character. The exchange interactions between electron spin are strong, local, and independent on the length of the p bridge.
We discuss how magnetic phenomena affect superconductivity in simple metals, transition metals and alloys thereof, and dilute Rare-Earth alloys. It is shown both qualitatively and quantitatively that superconductors are sensitive probes for studying itinerant spin excitations, local spin excitations associated with nearly magnetic impurities, the effect of the atomic environment on the stability of local magnetic moments, and the nature of the spin order in Rare-Earth alloys. Also, we discuss how magnetic impurities can be used to study the electronic configuration which is responsible for superconductivity in Laves-phase crystals like A-15 compounds and ..beta..-W crystals, for example.
The magnetization of ultrathin bcc Fe films (two and three monolayers) on MgO was measured and compared with the behavior predicted for a two-dimensional ferromagnet. The experiment indicated that no hysteresis was present in the magnetization. Instead, the magnetization at low temperature was affected by a marked field cooling effect. These observations lead to the conclusion that films of Fe on MgO of such thickness exhibit superparamagnetic behavior as if they were not entirely continuous. In contrast, films thicker than five monolayers exhibit a magnetic response close to that of bulk iron.
It has been carried out the magnetic properties determination for high iron oxide content glasses series obtained from a geothite red mud waste from the zinc hydrometallurgy and dolomite and glass cullet as main raw materials. It has been determined the magnetic susceptibility and magnetization values for the glasses here investigated. The results suggest that the magnetic behaviour are depending on the glass chemical composition, so that glasses can be differently classified like ferrimagnetic, ferromagnetic, superparamagnetic and paramagnetic. (Author) 6 refs.
Magnetic fluctuations present in the paramagnetic Mn{sub 0.81}Ni{sub 0.19} system have been investigated by measuring inelastic magnetic neutron scattering from a single crystal at temperatures of 450, 585 and 700 K. Antiferromagnetic correlations are observed to be present at all the temperatures studied. The spectral width of the magnetic scattering has been observed to increase with temperature, while the spatial range of the magnetic correlations is seen to decrease as the temperature is raised. The wave-vector-dependent susceptibility is found to follow a Curie-Weiss law near the (1 0 0) position, in agreement with theoretical predictions.
It is suggested that the magnetic Ap stars can be rotationally decelerated to long periods by the braking action of the associated magnetic field on time scales of order 10"7--10"1"0 years depending on whether the star's dipole field is aligned perpendicular or parallel to the rotation axis. Rotation includes a toroidal magnetic field in the plasma surrounding a star, and the accompanying magnetic stresses produce a net torque acting to despin the star. These results indicate that it is not necessary to postulate mass loss or mass accretion for this purely hydromagnetic braking effect.
The homogeneity of the magnetic field in the LHC dipoles strongly depends on the correct position of the superconducting cables: this is related to the quality of the dipole components, such as the dimension of the coil spacers (copper wedges), of the cable and of the collars. The performance in operational conditions is also affected by the magnetization of the cables. In this work, we analyse the measurements of these quantities during the production of the 1276 LHC dipoles, their trends, and the relation to the measured magnetic field. A novel mtehod to locate electrical shorts based on the analysis of magnetic measurements is also presented, and applications to 15 dipoles reascued during the production is given.
As low temperature cryocoolers become more frequently used to cool superconducting magnets, it becomes increasingly apparent that the connection between the cooler and the magnet has an effect on the design and performance of the magnet. In general, the use of small coolers can be considered in two different temperature ranges; (1) from 3.8 to 4.8 K for magnet fabricated with LTS conductor and (2) from 18 to 35 K for magnets fabricated using HTS conductor. In general, both temperature ranges call for the use of a two-stage cooler. The best method for connecting a cooler to the magnet depends on a number of factors. The factors include: (1) whether the cooler must be used to cool down the magnet from room temperature, (2) whether the magnet must have one or more reservoirs of liquid cryogen to keep the ...
Anisotropic Nd{endash}Fe{endash}B magnet powders can be produced by the hydrogenationdecomposition-desorption-recombination (HDDR) process from Nd{endash}Fe@ xnB{endash}Co{endash}M ({ital M}=Ga, Zr, Nb, Hf, and Ta) alloys. The present status of those HDDR powders and the bonded magnets made from them are reviewed with regards to the powder particle size dependence of their magnetic properties, their magnetic thermal stability, and their magnetization behavior. The results of a mechanistic study on the recombination step are also presented. The magnetic properties of the anisotropic HDDR powder depend relatively little on the powder particle size. Bonded magnets with a density of {approximately}6.20 g/cm{sup 3} and a BH{sub max} of 18.5{endash}20.5 MGOe can be produced from anisotropic HDDR powders with particle sizes of below 300 {mu}m diam. ...
Kelvin-Helmholtz instability of short gravity waves is examined in order to explain the recent findings of the decrease in momentum transfer from hurricane winds to sea waves. A three-fluid configuration of a foam layer between the atmosphere and the ocean is suggested to provide signifficant stabilization of the system and shifting the marginal critical wavelength to the shortwave part of the spectrum. It is conjectured that such stabilization leads to the observed drag reduction. The high contrasts in three fluid densities provide a universal mechanism for stabilizing surface perturbations.
Warm-intermediate inflationary universe models in the context of braneworld cosmologies, are studied. This study is done in the weak and strong dissipative regimes. We find that, the scalar potentials and dissipation coefficients in terms of the scalar field, evolves as type-power-law and powers of logarithms, respectively. General conditions required for these models to be realizable are derived and discussed. We also study the scalar and tensor perturbations for each regime. We use recent astronomical observations to constraint the parameters appearing in the braneworld models.
We study the WZNW models based on nonstandard bilinear forms. We approach the problem from algebraic, perturbative and functional exact methods. It is shown that even in the case of integer k we can find irrational CFT's. We prove that when the base group is noncompact with nonabelian maximal compact subgroup, the Kac-Moody representations are nonunitary.
Numerical results on aeroelastic standard configurations are presented. The methods used for two dimensional configurations include the small perturbations approach for inviscid flow, coupling methods for unseparated flow, coupling methods for unseparated or separated, laminar or turbulent boundary layers, and a numerical solution of the Euler equations for inviscid flow. The three dimensional configurations are studied by the transonic small disturbance approach. The detailed results are given.
The work is devoted to a microscopic analysis of the reactive capacity of chitin. An algorithm for modeling the deacetylation reaction in a monomeric unit of chitin is described. The reaction coordinate and the potential energy surface topography are determined taking into account the electron-vibrational interaction and low-symmetry perturbations within Jahn-Teller theory. Based on this algorithm, the topological modeling of the deacetylation process is performed for the first time and a mechanism of the biological activity of chitosan is proposed.
The authors solve the two-dimensional stefan problem of solidification in a half-space, where the heat flux at the wall is a slightly varying function of positioning along the wall, by means of a large Stefan number approximation (which turns out to be equivalent to a small time solution), and then by means of the Heat Balance Integral Method, which is valid for all time, and which agrees with the large Stefan number solution for small times. A representative solution is given for a particular form of the heat flux perturbation.
The nucleon axial charge is calculated as a function of the pion mass in full QCD. Using domain wall valence quarks and improved staggered sea quarks, we present the first calculation with pion masses as light as 354 MeV and volumes as large as (3.5 fm)3. We show that finite volume effects are small for our volumes and that a constrained fit based on finite volume chiral perturbation theory agrees with experiment within 5% statistical errors.
A method to deduce the 2 x 2 transport matrix for coupled heat and particle transport in Tokamaks is proposed. The method applies to perturbative experiments, and is based on a Fourier transform of the measured signals of temperature and density. By analyzing different linear combinations of temperature and density, the eigenvectors and eigenvalues of the transport matrix are determined. The method is tested for a number of illustrative cases using simulated data, and the sensitivity to noise on the signals is evaluated. (author).
The Cutkosky rules are generalized to include tachyons. A consequence is that Lorentz-invariant interacting theories which possess tachyons cannot obey even the weakest possible form of unitarity beyond the tree level. The problem (although not the cutting rules) is shown to extend to bosonic string theory. Thus unitarity cannot be used to determine the range of modular integration in bosonic string loop amplitudes.
The Cutkosky rules are generalized to include tachyons. A consequence is that Lorentz-invariant interacting theories which possess tachyons cannot obey even the weakest possible form of unitarity beyond the tree level. The problem (although not the cutting rules) is shown to extend to bosonic string theory. Thus unitarity cannot be used to determine the range of modular integration in bosonic string loop amplitudes.
The early idea that a non-perturbative gluon condensate affects the spectrum of heavy quarks is revisited in the light of modern simulation techniques. We evaluate the low lying spectrum of bound states of two heavy quarks for large hypothetical quark mass, m_Q > m_b, using non-relativistic QCD and compare with other models to test the consistency.
The steady-state advective flow in a long horizontal rectangular channel with rigid adiabatic boundaries in the presence of a uniform longitudinal pressure gradient is investigated. The stability of this flow with respect to perturbations of various types is studied. The dependence of the critical Rayleigh number on the Prandtl number is found for various aspect ratios.
A new channel of nonlinear ionization of quantum system in a strong laser field is discussed. The probability of spontaneous radiation decay from the ground state in a short-range potential to the final Volkov wave function, is calculated by the first order of the perturbation theory. It is shown that this process at high intensities of the laser field will be comparable with the high harmonic generation. (orig.)
The inhibitor action of unbranched polyamines on corrosion of low-carbon steel in 0.5 M sulfuric acid is studied through potentiostatic polarization curves. It is shown that the inhibitor efficiency I depends on the polyamine concentration and molecular structure. The quantum-mechanical calculations of molecular properties are accomplished through the MNDO method. Correlation between the measured I and physicochemical properties of the polyamine inhibitors in protonized and nonprotonized form is found with application of the general perturbation theory
The title of the workshop, ''The QCD Phase Transitions'', in fact happened to be too narrow for its real contents. It would be more accurate to say that it was devoted to different phases of QCD and QCD-related gauge theories, with strong emphasis on discussion of the underlying non-perturbative mechanisms which manifest themselves as all those phases. Before we go to specifics, let us emphasize one important aspect of the present status of non-perturbative Quantum Field Theory in general. It remains true that its studies do not get attention proportional to the intellectual challenge they deserve, and that the theorists working on it remain very fragmented. The efforts to create Theory of Everything including Quantum Gravity have attracted the lion share of attention and young talent. Nevertheless, in the last few years there was also a tremendous progress and even some shift of attention toward emphasis on ...
The title of the workshop, ''The QCD Phase Transitions'', in fact happened to be too narrow for its real contents. It would be more accurate to say that it was devoted to different phases of QCD and QCD-related gauge theories, with strong emphasis on discussion of the underlying non-perturbative mechanisms which manifest themselves as all those phases. Before we go to specifics, let us emphasize one important aspect of the present status of non-perturbative Quantum Field Theory in general. It remains true that its studies do not get attention proportional to the intellectual challenge they deserve, and that the theorists working on it remain very fragmented. The efforts to create Theory of Everything including Quantum Gravity have attracted the lion share of attention and young talent. Nevertheless, in the last few years there was also a tremendous progress and even some shift of attention toward emphasis on ...
Molecular dynamics computer simulations of a dense nanocrystalline Nickel sample are performed on the parallel Cray T3 (EPFL-Lausanne). The sample contains 50 grains with an average size of 3 nm. By perturbing the relaxed configuration elastic and plastic properties are studied. (author) 1 fig., 1 ref.
The hydrogen bonding of ligated water in ferric, high-spin, resting-state substrate complexes of heme oxygenase from Neisseria meningitidis has been systematically perturbed...Full Text Available
Based on the nonlinear dispersion relation of electromagnetic wave in relativistic plasma, the nonlinear controlling equation for linearly polarized mode is obtained using Karpman's method. The modulation instability of intense laser pulse propagating through relativistic plasma is analyzed and the modulation instability growth rate as a function of perturbation wave number for laser beam propagating through relativistic plasma is given. (authors)
In these notes I discuss various aspects of the elusive M-theory, with a special stress on the structure of the supergravity effective descriptions and their relations. These notes are arranged into 7 chapters: (1) Introducing the supergravities, (2) The bound state problem, (3) Unitary and supergravity theories, (4) Superstring theory considerations, (5) Non-perturbative contributions, (6) Unitary techniques in supergravity theories, and (7) Instantons computation and the adS/sCFT correspondence.
The observation by Maday in 1974 that the Schmidt-Duffin solution to the optimal fin profile problem was flawed due to neglect of the slant height factor led to a new solution--actually, a demonstration of the ill-posedness of the question--by Snider. The present article proves mathematically that omission of this factor leads inevitably to underestimation of the heat transfer capability of any fin. Additionally, a perturbation scheme for estimating the correction for this effect is derived for configurations with low generalized Biot numbers, and a revised assessment of the performance of the Schmidt fin is presented.
We calculate the S-wave scattering lengths for charmed mesons scattering off Goldstone bosons and explore their quark mass dependence using the chiral perturbation theory up to next-to-leading order as well as a unitarized version of it. The quark mass dependence of all scattering lengths determined in a recent lattice calculation can be reproduced by the unitarized version. We also discuss signals of possible bound states in these observables. (orig.)
This report is composed of the following two parts and appendix. (I) Improvement of the Method for Evaluating Reactivity Based on Monte Carlo Perturbation Theory: Theoretical formulation in Monte Carlo perturbation method had been checked, and then introduced into a calculation code. There are some cases that the results of the change of eigenvalues becomes positive or negative by changing the estimator, and there is no reasonable difference in the results between the conventional method, which does not consider the change of neutron source distribution caused by a perturbation, and the new method, which consider that change. Thus it is still necessary to check the Monte Carlo perturbation code. (II) Improvement of Nodal Transport Method for 3-D Hexagonal Geometry: We can accurately evaluate hexagonal geometry FBR core by nodal transport calculation code for hexagonal-Z geometry named `NSHEX`. However ...
This talk is a brief review of gaugino condensation in superstring effective field theories and some related issues (such as renormalization of the gauge coupling in the effective supergravity theories and modular anomaly cancellation). As a specific example, we discuss a model containing perturbative (1-loop) corrections to the K{umlt a}hler potential and approximate S-duality symmetry.
The t<0 branch of pre-big bang cosmological scenarios is subject to a gravitational wave instability. The unstable behaviour of tensor perturbations is derived in a very simple way in Hwang's covariant and gauge-invariant formalism developed for extended theories of gravity. A simple interpretation of this instability as the effect of an ''antifriction'' is given, and it is argued that a universe must eventually enter the expanding phase. (orig.)
Analytical solutions are derived for a flow in a semi-infinite vertical porous medium with heat and mass transfer. When the temperature and mass concentration are uniform a constant pressure is possible and sustains a fully developed flow. Thereafter there is a small perturbation on the wall temperature and concentration and the subsequent two-dimensional problem is tackled for a large Prandtl number, free convection parameters and small Reynolds number. The heat transfer rate at the wall is discussed quantitatively.
We report on the calculation of multi-loop Feynman integrals for single-scale problems by means of difference equations in Mellin space. The solution to these difference equations in terms of harmonic sums can be constructed algorithmically over difference fields, the so-called {pi}{sigma}{sup *}-fields. We test the implementation of the Mathematica package Sigma on examples from recent higher order perturbative calculations in Quantum Chromodynamics. (orig.)
A two-beam spectroscopy (TBS) system is evaluated theoretically and experimentally. This new spectroscopic technique uses correlations between components of emitted light separated by a small difference in angle of propagation. It is thus a non-perturbing plasma diagnostic which is shown to provide local (as opposed to line-of-sight averaged) information about fluctuations in the density of light sources within a plasma - information not obtainable by the usual spectroscopic methods. The present design is an improvement on earlier systems proposed in a thesis by Rostler.
This progress report consists of an article, the abstract of which follows, and apparently the references and vita from a proposal. A review of perturbation diagnostics applied to microwave resonant cavity discharges is presented. The classical microwave perturbation technique examines the shift in the resonant frequency and cavity quality factor of the resonant cavity caused by low electron density discharges. However, modifications presented here allow the analysis to be applied to discharges with electron densities beyond the limit predicted by perturbation theory. An {open_quote}exact{close_quote} perturbation analysis is presented which models the discharge as a separate dielectric, thereby removing the restrictions on electron density imposed by the classical technique. The {open_quote}exact{close_quote} method also uses measurements of the shifts in the resonant conditions of the cavity. Thirdly, ...
The ..beta.. decay half-lives of neutron-rich isotopes with Z=24-28 are calculated in the QRPA with a Gamow-Teller residual interaction. For odd-mass and odd-odd systems QRPA phonon correlations are introduced to quasiparticle transitions in first-order perturbation. The calculated half-lives agree very well with the experimental values. For later application of this model to nuclei far from stability, we have examined the dependence of the calculated half-lives on the model parameters.
The #beta# decay half-lives of neutron-rich isotopes with Z=24-28 are calculated in the QRPA with a Gamow-Teller residual interaction. For odd-mass and odd-odd systems QRPA phonon correlations are introduced to quasiparticle transitions in first-order perturbation. The calculated half-lives agree very well with the experimental values. For later application of this model to nuclei far from stability, we have examined the dependence of the calculated half-lives on the model parameters. (orig.).
Bosonic colored group field theory is considered. Focusing first on dimension four, namely the colored Ooguri group field model, the main properties of Feynman graphs are studied. This leads to a theorem on optimal perturbative bounds of Feynman amplitudes in the ''ultraspin'' (large spin) limit. The results are generalized in any dimension. Finally, integrating out two colors we write a new representation, which could be useful for the constructive analysis of this type of models. (orig.)
Temperature-sensitive mutants defective in 60S ribosomal subunit protein L16 of Saccharomyces cerevisiae were isolated through hydroxylamine mutagenesis of the RPL16B gene and plasmid shuffling. Two...Full Text Available
An interface-marker technique has been used to investigate the relative rates of diffusion of Si and of metal atoms during the growth of metal silicide films. The technique enables recognition of a reference plane in thin film diffusion using Rutherford backscattering, while minimizing any perturbation of the diffusion process. Examples are drawn from studies of the growth of silicides of W, Mo, Ta, Nb, Pd and Pt. (orig.).
Toroidicity Alfven Eigenmodes (TAE) in ITER can be driven unstable by two groups of energetic particles, the 3.5 MeV {alpha}-particle fusion products and the tangentially injected 1MeV beam ions. Stability conditions are established using the perturbative NOVA/NOVA-K codes. A quasi-linear diffusion model is then used to assess the induced redistribution of energetic particles.
The acceptances to be obtained during the first operational run, refer to measures proving the functional integrity of the turbine control system and assuring the compliance with the maximum allowable overspeed in case of lead changes or perturbations. The Guideline concerns essentially speed, power, and pressure controllers coupled to generators. It may be appropriately extended to steam turbines serving other purposes.
Measurements of the magnetic susceptibility betweeen 0.03 and 300 K and of the magnetization between 0.05 and 10 K for magnetic fields up to 60kOe have been used to investigate effects from the interaction between the conduction electrons and local magnetic moments in (Lasub(1-x)Cesub(x))B_6 alloys (0.0007<=x<=0.10). For Ce concentrations x<0.006 the data show Kondo-type single impurity behaviour at low temperatures with a transition from a magnetic to a non-magnetic regime of the Ce ions. In the magnetic regime the impurity susceptibility follows a Curie-Weiss law, and in the non-magnetic regime it varies with T"2. An external magnetic field gradually restores the free-ion behaviour of the Ce impurities. For more concentrated alloys interactions between the impurities are observed. The RKKY ...
The magnetic separation technology using sub-microsized ferromagnetic particle is indispensable in many areas of medical biosciences. For example, ferromagnetic particles (200-500 nm) are widely used for cell sorting in stem cell research with the use of cell surface-specific antigens. Nanosized ferromagnetic particles (10-20 nm) have been suggested as more suitable in drug delivery studies given their efficiency of tissue penetration, however, the magnetic separation method for them has not been established. One of the major reasons is that magnetic force acting on the object particles decreases drastically as a particle diameter becomes small. In this study, magnetic force acting on the targets was enhanced by the combination of superconducting magnet and the filter consisting of ferromagnetic particle. By doing so, we confirmed that Fe{sub 3}O{sub 4} of 20 nm in diameter was ...
Magnetic drug targeting, using core-shell magnetic carrier particles loaded with anti-cancer drugs, is an emerging and significant method of cancer treatment. Gold shell-iron core nanoparticles (Fe@Au) were synthesized by the reverse micelle method with aqueous reactants, surfactant, co-surfactant and oil phase. XRD, XPS, TEM and magnetic property measurements were utilized to characterize these core-shell nanoparticles. Magnetic measurements showed that the particles were superparamagnetic at room temperature and that the saturation magnetization decreased with increasing gold concentration. The anti-cancer drug doxorubicin (DOX) was loaded onto these Fe@Au nanoparticle carriers and the drug release profiles showed that upto 25% of adsorbed drug was released in 80 h. It was found that the amine (-NH2) group of DOX binds to the gold shell. An in vitro apparatus simulating the human ...
With "1"5"1Eu-Moessbauer spectroscopy and other methods the complex magnetic properties of Eu_2PdSi_3, arising from the two crystallographically different lattice sites of the Eu"2"+ ions, have been already studied. Here we study the impact of magnetic dilution of the magnetic Eu"2"+ sites by non-magnetic Y"3"+ ions. A previous specific heat study has found reduced magnetic ordering temperatures with strong indication of disorder effects like in magnetic spin glasses. Here we provide from "1"5"1Eu-Moessbauer spectroscopy detailed information of the impact of Y"3"+ substitution on the magnetic properties of the two lattice sites, well distinguishable in the "1"5"1Eu-spectra. Since the substitution of the larger Eu"2"+ ions by the smaller Y"3"+ ions is connected with a lattice contraction, we also applied high pressure to the Eu_2PdSi_3 sample ...
The electrical resistivity, Hall effect, and magnetic susceptibility of single-crystal UPd_2Si_2 have been studied between 4.2 and 300 K. A large anisotropy was observed in both the magnetic and transport properties. There is a quadratic temperature dependence of the resistivity for a range of temperatures between 4.2 and 80 K. At higher temperatures, the resistivity indicates a Kondo-type behavior. The behavior of these quantities is accounted for by the magnetic phase transitions at 108 and 136 K reported from neutron-scattering studies. At high temperatures, the magnetic susceptibility of UPd_2Si_2 is Curie-Wiess-like along the c axis. The temperature dependence of the Hall coefficient above 108 K is accounted for by a theoretical model invoking skew scattering of conduction electrons by localized magnetic moments.
The electrical resistivity, Hall effect, and magnetic susceptibility of single-crystal UPd[sub 2]Si[sub 2] have been studied between 4.2 and 300 K. A large anisotropy was observed in both the magnetic and transport properties. There is a quadratic temperature dependence of the resistivity for a range of temperatures between 4.2 and 80 K. At higher temperatures, the resistivity indicates a Kondo-type behavior. The behavior of these quantities is accounted for by the magnetic phase transitions at 108 and 136 K reported from neutron-scattering studies. At high temperatures, the magnetic susceptibility of UPd[sub 2]Si[sub 2] is Curie-Wiess-like along the [ital c] axis. The temperature dependence of the Hall coefficient above 108 K is accounted for by a theoretical model invoking skew scattering of conduction electrons by localized magnetic moments.
The Recycler ring magnet will be made of Strontium ferrite permanent magnets. A strontium ferrite permanent magnet without compensation has a temperature coefficient of -0.2 % in dB/dT. To compensate this effect, we are utilizing 30 % Ni 70 % Fe alloy, a temperature compensation ferromagnetic material with a low Curie point. To search for optimum commercially available material and optimum condition, we made a couple of simple model magnets, and tested with several different compensating material. The test results are reported and its optimal conditions are shown. Several different configurations were tested including a possible 2 kG magnet configuration.
We report on the magnetic hyperthermia properties of chemically synthesized ferromagnetic 11 and 16 nm Fe(0) nanoparticles of cubic shape displaying the saturation magnetization of bulk iron. The specific absorption rate measured on 16 nm nanocubes is 1690+-160 W/g at 300 kHz and 66 mT. This corresponds to specific losses-per-cycle of 5.6 mJ/g, largely exceeding the ones reported in other systems. A way to quantify the degree of optimization of any system with respect to hyperthermia applications is proposed. Applied here, this method shows that our nanoparticles are not fully optimized, probably due to the strong influence of magnetic interactions on their magnetic response. Once protected from oxidation and further optimized, such nano-objects could constitute efficient magnetic cores for biomedical applications requiring very large heating power.
The magnetic properties of polycrystalline and single crystalline rare earth transition metal silicides Gd_xLa_1_-_xMSi (M =Fe, Co) were investigated. Magnetic measurements have been made in static magnetic fields up to 13 kOe and in pulsed magnetic fields up to 250 kOe in the temperature range from 4.2 to 350 K. The magnetic susceptibility in the paramagnetic state of all the investigated compounds obeys the Curie-Weiss law except for LaFeSi and LaCoSi. Increase of the La content in Gd_xLa_1_-_xFeSi compounds leads to a decrease of the Curie and Neel temperatures, which can be explained by a decrease of positive exchange interactions. (orig.).
Sensitive and quick-response nonlinear inductance characteristics are found for high Tc superconducting (YBa/sub 2/Cu/sub 3/O/sub 7-chi/) disk cores at 77K in which soft magnetic BH hysteresis loops are observed. Various quick response magnetic devices such as modulators, amplifiers and sensors are built using these cores. The magnetizing frequency can be set to more than 20 MHz, which is difficult for conventional ferromagnetic bulk materials such as Permalloy amorphous alloys and ferrite. New quick-response fluxgate type magnetic-field sensors are made using ac and dc voltage sources. The former is used for second-harmonic type sensors, while the latter is for voltage-output multivibrator type sensors. Stable and quick-response sensor characteristics were obtained for two-core type multivibrators.
The Advanced Photon Source injector synchrotron is a 7-GeV positron machine with a standard alternating gradient lattice. The calculated effect of dipole magnet strength errors on the orbit distortion, simulated by Monte Carlo, was reduced by sorting pairs of magnets having the closest simulated measured strengths to reduce the driving the term of the integer resonance nearest the operating point. This method resulted in a factor of four average reduction in the rms orbit distortion when all 68 magnets were sorted at once. The simulated effect of magnet measurement experimental resolution was found to limit the actual improvement. The {Beta}-beat factors were similarly reduced by sorting the quadrupole magnets according to their gradients.
We investigated the magnet field dependence of the X-ray pulse height and the critical current of a Ti/Au bilayer TES micro-calorimeter. The pulse height was strongly affected by the magnetic field intensity applied perpendicularly to the TES surface. We found that the critical current at zero temperature, I c0, decreased by a factor of two by applying a magnet field of ?10??T. Our data are consistent with a TES sensitivity proportional to (I/I c0)?2/3, as predicted by the Ginzburg-Landau theory. This fact implies that the shape of the R?T curve of the TES is partly determined by the critical current of the superconductor. In order to make our TES microcalorimeters less sensitive to the external magnetic field, we fabricated devices equipped with on-chip magnetic shielding. One device has ...
The Large Hadron Collider (LHC) will be equipped with several thousands of superconducting corrector magnets. Among the largest ones are the superconducting trim quadrupoles (MQTL). These twin-aperture magnets with a total mass of up to 1700 kg have a nominal gradient of 129 T/m at 1.9 K and a magnetic length of 1.3 m. Sixty MQTL are required for the LHC, 36 operating at 1.9 K in and 24 operating at 4.5 K. The paper describes the design features, and reports the measured quench performance and magnetic field quality of the production magnets. The MQTL magnet production is shared between CERN and industry. This sharing is simplified due to the modular construction, common to all twin-aperture correctors.
Effect of low-frequency pulsating magnetic field on the microstructure and magnetic properties of amorphous alloy Fe_7_8Si_9B_1_3 were investigated. The temperature rise induced by the treatment was measured by a non-contact infrared thermometer. The crystallization behavior and microstructure of specimens were studied by Moessbauer spectroscopy and transmission electron microscope (TEM). Magnetic properties of the specimens were investigated by alternating gradient magnetometer (AGM). The results show that the low-frequency pulsating magnetic field can promote the single-phase crystallization of amorphous alloy Fe_7_8Si_9B_1_3. The frequency, f of applied field is from 10 to 40 Hz, magnetic field, H is from 0.02 to 0.04 T and treatment duration, t is from 180-300 s. The volume fraction of crystallization phase (#alpha#-Fe(Si), the grain size, 2-10 nm) is 3-7%. The temperature rise ...
This paper discusses the possible detection of magnetic monopoles and monopole tachyons. Topics considered include insects, astrophysics, general relativity theory, plants, and biotechnology. The paper was presented at an international symposium on non-conventional energy technology.
The investigated hybrid nanocomposite consists of a porous silicon template with electrochemically embedded Ni or Co nanostructures and offers magnetic characteristics which can be tailored by the electrochemical process parameters during fabrication. A twofold magnetic behaviour can be observed, a first one due to the spinmagnetism at magnetic fields below the saturation magnetization of the deposited metals and a second non-saturating term at higher fields (>1 T up to 7 T) above the saturation magnetization. In case of Ni deposited within the pores this non-saturating term shows a paramagnetic characteristic and follows exactly the Curie-Weiss law, whereas for Co/porous silicon samples the temperature dependent magnetization shows some deviations from the Curie Weiss law. In this high field region a difference in the temperature dependence between Ni ...
The Time Projection Chamber (TPC) magnet at LBL and its compensation solenoids are adiabatically stable superconducting solenoid magnets. The cryogenic system developed for the TPC magnet is discussed. This system uses forced two-phase tubular cooling with the two cryogens in the system. The liquid helium and liquid nitrogen are delivered through the cooled load by forced tubular flow. The only reservoirs of liquid cryogen exist in the control dewar (for liquid helium) and the conditioner dewar (for liquid nitrogen). The operation o these systems during virtually all phases of system operation are described. Photographs and diagrams of various system components are shown, and cryogenic system data are presented in the following sections: (1) heat leaks into the TPC coil package and the compensation solenoids; (2) heat leaks to various components of the TPC magnet cryogenics system besides the ...
A new type of radiation which occurs when particles are accelerated in the field of a longitudinal wave and in a transverse magnetic field is studied. The characteristics of such spontaneous radiation are obtained, and the influence of collective effects on the radiation is analyzed. The application of the findings to the theory of free electron lasers is discussed. 8 references.
BackgroundMagnetic Resonance Imaging scanners have become ubiquitous in hospitals and high-field systems (greater than 3 Tesla) are becoming increasingly common. In light of recent...Full Text Available
The magnetic susceptibility and the density of human oxy-(HbO2) and carbonmonoxyhemoglobin (HbCO) solutions of various concentrations have been measured at room temperature, with pure water...Full Text Available
OBJECTIVES: This article uses meta-analysis methodology to examine the statistical consistency and importance of random variation among results of epidemiologic studies of residential magnetic field...Full Text Available
A new gadolinium chelating NIR fluorescent molecular probe increases T1 relaxivity of water protons, facilitating combined optical and magnetic resonance imaging.
The magnetic properties of as-grown Ga1-xMnxAs have been investigated by the systematic temperature and magnetic field dependent soft x-ray magnetic circular dichroism (XMCD) measurements in the Mn L2,3 absorption edge region. The XMCD intensity at high temperatures obeys the Curie-Weiss law, but residual spin magnetic moment appears already around 100 K, significantly above Curie temperature (Tc), suggesting that short-range ferromagnetic correlations are developed significantly above Tc. The high-field magnetic susceptibility becomes T-independent below TC, indicating that the AF interaction between the substitutional Mn (Mnsub and interstitial Mn (Mnint) ions, which becomes strong as the Mn concentration x increases, exists and that the amount of the Mnint affects Tc. The present experimental findings should give valuable insight into the inhomogeneous ...
OBJECTIVES: To define a method for measurement of the cross sectional area and volume of the quadriceps femoris muscle using magnetic resonance imaging (MRI) in conjunction with stereology, and to compare...Full Text Available
An in-plane uniaxial magnetic anisotropy has been observed in thin Co films normally deposited onto obliquely sputtered Ta and Pt underlayers. Associated with this anisotropy is an augmented easy axis coercivity. The in-plane easy axis is, in most cases, perpendicular to the incident deposition plane. Microstructural results indicate that grains are well connected along the magnetic easy axis but are separated by long continuous voids along the hard axis, which is ascribed to a geometric shadowing effect due to the oblique incidence deposition of the underlayer. Hence, the magnetic anisotropy mimics the film growth anisotropy. It is therefore believed that the observed magnetic properties are due to magnetostatic shape anisotropy effects. In-plane coercivity and anisotropy field are shown to increase with underlayer deposition angle, underlayer thickness and magnetic layer ...
A considerable amount of chemical knowledge of marine sediments has been acquired in recent years but has not yet been utilized by paleomagnetists. On the other hand, geochemists are often unaware of the usefulness of numerous magnetic techniques. In this review we try to bridge this gap, and in particular, we outline many of the chemical and magnetic principles that should allow paleomagnetists to better identify and undertand chemical changes that affect the magnetic properties of marine sediments. The chemical principles include those for distinguishing the four major sources of sediments (continental, biological, authigenic/hydrogenous, volcanic/hydrothermal) from one another by determining elemental abundance distributions, as well as for investigating the stabilities of mineral phases relative to changes in pE and pH. The magnetic principles include the effects of authigenesis and diagenesis on ...
ObjectiveUsing high resolution cardiovascular magnetic resonance (CMR), we aimed to detect new details of left ventricular (LV) systolic and diastolic function, to explain the twisting...Full Text Available
Major breakthroughs have recently been reported that can help overcome two inherent drawbacks of NMR: the lack of sensitivity and the limited memory of longitudinal magnetization. Dynamic nuclear polarization...Full Text Available
Quantitative probing of heterogeneous regions in muscle is feasible with phosphorus-31 magnetic resonance spectroscopy because of the differentiation of metabolic patterns of glycolytic and oxidative...Full Text Available
OBJECTIVES: To appraise epidemiological evidence of the purported association between residential exposure to power frequency magnetic fields and adult cancers. METHODS: Literature review and epidemiological...Full Text Available
Epidemiologic research concerning electric and magnetic fields in relation to cancer has focused on the potential etiologic roles of residential exposure on childhood cancer and occupational exposure...Full Text Available
Naturally occurring and contaminant ferromagnetic and ferrimagnetic particles have been found within or near cells, and might allow pulsed magnetic fields to create transient cell membrane opening ("pores")....Full Text Available
The purpose of this study was to assess the effect of a 735-kV transmission line on the electric and magnetic field exposures of people living at the edge of the line's right of way. Exposure of 18...Full Text Available
Bone metastases of an Ewing's sarcoma were detected by magnetic resonance imaging (MRI), when bone scan, CT and plain films were still normal. This is due to the ability of MRI to detect intramedullary metastases before involvement of the cortex. (Auth.).
A design of the modular coil system for CHS-qa has been made for the plasma configuration '2b32' with the aspect ratio 3.2. The magnetic field strength and the major radius are 1.5 T and 1.5 m, respectively. The normal component of magnetic field produced by the modular coils is minimized on the plasma boundary to obtain the optimum coil design. We put engineering constraint on the distance between adjacent modular coils and the radius of coil curvature. The dependence of the residual normal component of the field on these conditions is examined, and the realistic values for them are selected. Additional coils to control various properties of the magnetic field configuration (the rotational transform, the magnetic well depth, etc.) have been designed and a flexibility of the magnetic field configuration is realized. For the case that the rotational transform ...
The magnetically controlled plasma opening switch (MCPOS) is an advanced plasma opening switch that utilizes magnetic fields to improve operation. Magnetic fields always dominate terawatt, pulsed power plasma opening switches. For that reason, the MCPOS uses controlled applied magnetic fields with magnitude comparable to the self-magnetic field of the storage inductor. One applied field holds the plasma in place while energy accumulates in the storage inductor, then another applied field pushes the plasma away from the cathode to allow energy to flow downstream. Over a ten month period, an MCPOS was designed, built, and tested on DECADE Module 2 at Physics International. The peak drive current was 1.8 MA in 250 ns. The output parameters were up to 1 MA into an electron beam load. The radiation temporal pulse width averaged 60 nanoseconds full-width at half-maximum. The peak load ...
A technique of low-field pulsed proton nuclear magnetic resonance (NMR) spin relaxation is described for assessment of age-related structural changes (dentin and pulp) of human teeth in...Full Text Available
OBJECTIVES--This case cohort study examines whether there is an association between exposure to electric and magnetic fields and suicide in a population of 21,744 male electrical utility workers from...Full Text Available
Name U.S. Geological Survey A Helicopter-Borne Magnetic Survey over Dixie Valley Geothermal Field, Nevada: A Web Site for Distribution of Data by U. S. Geological Survey &...
A variable-dispersion electron spectrometer is being installed for use by the Stanford Superconducting Accelerator in conjunction with its Free Electron Laser program. The system has been designed to operate with electron beam energies from 20 MeV to 200 MeV, with a maximum energy resolution of 0.01% FWHM. The maximum energy acceptance is approximately #+-# 5%, as determined by the bending magnet aperture. Resolution is controlled by adjusting the focal conditions at the entrance to a 90 degree bending magnet, while the dispersion is controlled by changing the magnitude and polarity of the field in a quadrupole magnet which immediately follows the bending magnet. 4 refs., 5 figs.
... The Effect of the Temperature to Which the Material is Heated on the Process of Formation of Intermetallic Compounds in Magnetic Pulse Welding,. ...
The read/write characteristics for perpendicular magnetic recording media of focused-ion-beam (FIB)-etched recording heads were investigated. It was found that the trailing edge of an FIB-etched head produces a higher gradient in the magnetic field perpendicular to the medium than a head which has not been etched. The signal-to-noise ratio of the medium increased with the FIB-etched write gap. A high-Bs and thin pole increased the magnetic field's gradient in the perpendicular direction, resulting in excellent read/write characteristics.
It is both experimentally and theoretically demonstrated that ion flow velocity at an arbitrary angle with respect to the magnetic field can be measured with a directional Langmuir probe. Based on the symmetry argument, we show that the effect of magnetic field on directional probe current is exactly canceled in determining the ion flow velocity, and obtain the generalized relation between flow velocity and directional probe currents valid for any flowing direction. The absolute value of the flow velocity is determined by an in situ calibration method of the probe. The applicability limit of the present method to a strongly ion-magnetized plasma is experimentally examined. (author)
XVTa and XXTa nuclei were oriented at low temperature as dilute impurities in Fe. The magnetic hyperfine splitting frequencies = B sub(HF)/Ih of the XVTa and XXTa ground states have been measured to be 320.45(11) and 317.552(55) MHz by using the technique of NMR-ON. Taking the known hyperfine field of Y Ta in Fe, the magnetic moments have been deduced: ( XVTa, 7/2 ) =2.270(45) and ( XXTa, 7/2 ) =2.250(45) sub(N). These values of the magnetic moments are discussed in the framework of the rotational model.
The paramagnetic susceptibility of single crystals of dysprosium-yttirum alloys is measured in the basal plane and along the hexagonal axis. It is shown that the susceptibility of the alloys obeys the Curie-Weiss law, the effective magnetic moments allong the different directions being the same and the paramagnetic Curie temperatures being different. The difference between the paramagnetic Curie temperatures in the basal plane and along the hexagonal axis is independent of the dysprosium concentration in the alloy. As a comparison with the theoretical models of magnetic anisotropy shows, this is an indication that the magnetic anisotropy of dysprosium - yttrium alloys is of a single-ion nature.
A method to achieve NMR of dilute samples in the earth's magnetic field by applying para-hydrogen induced polarization is presented. Maximum achievable polarization enhancements were calculated by numerically simulating the experiment and compared to the experimental results and to the thermal equilibrium in the earth's magnetic field. Simultaneous 19F and 1H NMR detection on a sub-milliliter sample of a fluorinated alkyne at millimolar concentration (1018 nuclear spins) was realized with just one single scan. A highly resolved spectrum with a signal/noise ratio higher than 50:1 was obtained without using an auxiliary magnet or any form of radio frequency shielding.
This review of methods and designs of transducers for nondestructive determination of the magnitude and nature of the anisotropy of magnetic properties (permeability, induction, coercive force, energy loss due to magnetization reversal) in local portions of ferromagnetic sheet and, in some cases, in individual parts of products. The need to measure the anisotropy is considered for two angles: for the case when the anisotropy is due to the crystallographic texture and determines the main operating characteristics of widely used sheet such as electrical steel and automobile body sheet, and for crystallographically isotropic materials, in which the anisotropy of magnetic properties as a result of mechanical stresses is a measure for determining the internal stresses.
The magnetic structure of a tetragonal Ce(Ru_0_._9_6Pd_0_._0_4)_2Si_2 single crystal, determined by neutron diffraction measurements, is similar to that observed in Rh doped alloys. The magnetic moments are oriented and modulated along the c-axis. Here the wave vector is incommensurate: k=(0,0,0.38). At 1.5 K, the moment is estimated to about 0.3 #mu#_B. Magnetization, magnetoresistance and Hall effect measurements performed on this alloy are also reported. (orig.).
The a.c. susceptibility and high field magnetization of TbRh{sub 2-x}Pd{sub x}Si{sub 2} and TbRu{sub 2-x}Pd{sub x}Si{sub 2} compounds were investigated up to 140 kOe. The (T, x) magnetic phase diagrams were determined. For both systems, an increase in the Pd content causes a decrease in the Neel temperature and changes the magnetization curves. (orig.)
The combined magnetic braking-ambipolar diffusion problem in weakly ionized, rigidly rotating disks is studied. An analytical solution is presented for a disk whose angular velocity and magnetic yield vectors are aligned with the symmetry axis, illustrating the effects of the relative azimuthal drift of neutrals and ions. The effects of radial drift are added, commenting on the ratio of the characteristic ambipolar diffusion and magnetic braking time scales in high-mass and low-mass disks. A numerical calculation is used to show the combined action of these two processes. 31 references.
The effect of elastic and plastic strains on the magnetic properties of ferrite-pearlite steels has been studied. It has been shown that the sensitivity to elastic-tensile and bending strains is four to five times greater for remnant magnetization than for coercive force. In order to determine the degree of cold plastic deformation of high-carbon steels, a two-parametric testing technique based on the use of remnant magnetization and coercive force was suggested. An MMT-2 device was recommended for measurement of the required parameters.
The author briefly discusses definition of terms, gives an introduction to measurement techniques and describes the characteristics of various low-frequency fields and their causes using typical examples: natural electric fields (thunderstroms), natural magnetic fields, technical electric constant fields (urban transportation, households), static magnetic fields (urban transportation, nuclear magnetic resonance imaging), technical electric alternating fields (high-voltage transmission lines, households), and magnetic alternating fields (high-voltage transmission lines). The author discusses both occupational exposure and that of the general public while underpinning his statements by numerous tables, measurement diagrams and charts. (Uhe).
An accelerator has limited dynamic range: a chain of accelerators is required to reach high energy. A combination of septa and kicker magnets is frequently used to inject and extract beam from each stage. The kicker magnets typically produce rectangular field pulses with fast rise- and/or fall-times, however the field strength is relatively low. To compensate for their relatively low field strength, the kicker magnets are generally combined with electromagnetic septa. The septa provide relatively strong field strength but are either DC or slow pulsed. This paper discusses injection and extraction systems with particular emphasis on the hardware required for the septa.
The magnetoresistance in an FeNi submicron-structure comprising two wires of 80 and 200 nm in width connected in series was measured at 77 K. When the external magnetic field was applied parallel to the wire axis, two switching fields corresponding to the distinct coercive force of the two wires were observed. When the external magnetic field was applied at an angle of {theta}>30 deg. to the wire axis one switching field was observed, indicating simultaneous magnetization reversal in both wires. This indicates that the domain-wall trapping around the joint can be controlled systematically in terms of the direction of the external magnetic field.
The authors have performed a preliminary design for a persistent GHz NMR magnet at 23.5 T and 1.8 K operating conditions. In this paper the authors shall address the issues of realistic conductor selection, the coil design, the magnetic and mechanical analysis of the coil, and the required field uniformity. In addition, they shall describe the GHz magnet cryostat with a practical 1.8 K J-T refrigerator system. Finally vibration isolation system and field shield design and its associated field harmonics will be analyzed.
... fields, materials can be subjected to energy densities exceeding those realized in high explosives, a fact which forms the basis for magnetic forming ...
T{sub 2} weighted ultra-short turbo spin echo sequences were used in five individuals with variations in echo times, delayed triggering and echo intervals. To reduce movement artifacts all examinations were carried out with ECG and respiratory triggering. The sequences giving optimal image quality were then employed in 19 patients having various pulmonary abnormalities. Image resolutions, artifacts, image contrasts and diagnostic value were then judged by two observers and compared with CT. In the first study, a diastole-triggered UTSE sequence with the shortest echo proved optimal (T{sub E}=90 ms, T{sub R}=2-4 s, echo=9 ms, turbo factor=19). In the patient series studied, MRT was inferior to CT with regard to resolution and number of artifacts, but better in respect of contrast and diagnostic value. Using UTSE of the lung, MRT can produce images of good quality. Compared with CT, contrast is better with MRT, offering ...
The results of the investigations show that magnetic treatment is a quite practical and effective method of intensifying certain technological processes in the coking industry. Magnetic treatment was utilized for improving the production of ammonium sulfate, refining of the naphthalene fraction, removal of sludge from wash oil in the benzol division, and the treatment of tar before fractionation. 2 references, 3 tables.
The concept of the minimum propagating zone (MPZ) is used to examine the causes of quenches in ISABELLE cosine theta superconducting dipole magnets. The size of disturbances large enough to exceed the MPZ and initiate quenches is estimated and compared with the size of disturbances which may be produced in the magnets. A suggestion for reducing the size of these disturbances through individual support of the coil block is outlined.
The paper deals with a model in which the motion of a gas in plasma accerators and high-curent discharges in the present of a skin effect is treated as expulsion by a 'magnetic piston' under the action of surface current flow. Specifically examined is the situation where the initial gas pressure is negligible in comparison with the magnetic pressure, and the motion of the gas may be treated as a self-simulating one. A system of hydrodynamic equations of the problem is derived and integrated by Adam's method. Results are plotted and discussed.
High-spin states in {sup 202}Pb and {sup 203}Pb have been investigated by in-beam {gamma}-ray spectroscopy following the reaction {sup 198}Pt({sup 9}Be,xn). A search for magnetic rotational bands in these isotopes confirmed one of the two bands previously assigned to {sup 202}Pb and revealed a new band in this isotope. No evidence for magnetic rotation has been found in {sup 203}Pb. (orig.)
Plasma confinement by permanent magnets has been studied. An analytic formula for the field of a single bar magnet has been obtained. Generalization to various configurations of multidipole fields has also been found. Any two-dimensional field may now be completely described by a simple function of complex variables in closed form. Vector potential has also been obtained by integrating over a prescribed Riemann surface. The confinement of plasma by multidipole fields then becomes obvious through conservation principles.
Due to biological effects of magnetic fields of high voltage transmission lines and induced effects on has pipe line, telecommunication system and interference with sensitive electronic equipment, many effort have been done to reduce transmission lines magnetic fields and several ideas have been introduced. In this paper we review three methods: phase split, shielded and compacted line methods. With aid of a developed software programme these methods are then applied to transmission lines and the results are analyzed.
Measurement of the magnetic susceptibility of powder samples of heavy rare-earth (Tb, Dy, Ho, Er, Tm and Yb) tungstates have been reported in the temperature range 300 to 900 K. Curie-Weiss law behaviour has been observed for all samples. The Curie constant, paramagnetic Curie temperature and magneton number for the magnetic ions have also been evaluated for each material. (author).
Results of experimental researches of impurity level crystals Fe1-xCoxSi are presented in this article. Magnetic properties in a temperature range up to T {<=} 1000 K are analyzed. It was established that with Co impurities increasing origin of magnetic ordering exists at low temperatures. At high temperatures a high temperature maximum of susceptibility of nominally pure iron monosilicide crystal is observed.
This report continues the studies of simplified methods, of magnetic diagnostics in application to TCA/BR tokamak. Here we study the accuracy of known formula for {beta}{sub 1} + l{sub 1}/2 determination from the poloidal magnetic field asymmetry. Errors of the diamagnetic measurements due to vibrations of the vacuum vessel are also considered. (author). 3 refs., 1 fig., 1 tab.
We report on solid solution CePd_2_-_xMn_xSi_2 which shows an interesting transition of the Ce-ion from magnetism in a Kondo regime to an intermediate valence state coupled with a strongly magnetic 3d sublattice. ((orig.)).
We report on solid solution CePd[sub 2-x]Mn[sub x]Si[sub 2] which shows an interesting transition of the Ce-ion from magnetism in a Kondo regime to an intermediate valence state coupled with a strongly magnetic 3d sublattice. ((orig.))
Calculating the local spectral densities at magnetic adatoms, we estimate the variation in the Yosida-Kondo resonance due to the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction and the direct exchange between adatoms in systems of magnetic trimers on metal surfaces. The results show that the RKKY interaction leads to the gradual variation in Kondo temperature, and the direct exchange can be the origin of the drastic variation. (author)
The gauge-invariant correlation function for the Yang-Mills field strengths is shown to admit a symmetric decomposition into electric and magnetic components. The spectral weights are seen to obey a sum rule of the superconvergence type, owing to asymptotic freedom. The close relation between the dielectric function, electric-magnetic duality, and the algebra of generalized Chern-Simons charges is illustrated for the linearized Yang-Mills-Higgs system.
The purpose of this paper is to demonstrate how recent experimental results of "1"5"1Eu and "5"7Fe high pressure Moessbauer studies in 4f and 3d metallic magnetic systems can contribute to a deeper understanding of the nature of local moment (4f) and itinerant (3d) magnetism in these systems. Special emphasis is given on the comparison of the experimental results with related theoretical models. (orig.).
Ferrofluids have promising potential for heat transfer applications, since advective transport in a ferrofluid can be readily controlled by using an external magnetic field. However, unlike conventional free or forced convection, ferrohydrodynamic convection is not yet well characterized. A full understanding of the relationship between an imposed magnetic field, the resulting ferrofluid flow, and the temperature distribution is a prerequisite for the proper design and implementation of applications involving thermomagnetic convection. The literature variously assumes constant magnetic fields, does not completely represent the variation in the imposed field, or its descriptions are inaccurate, since the fields do not comply with the Maxwell's equations of electromagnetism. We address this by simulating two-dimensional forced convection heat transfer in a channel with a ferrofluid that is under the influence of a ...
Ferrofluids have promising potential for heat transfer applications, since advective transport in a ferrofluid can be readily controlled by using an external magnetic field. However, unlike conventional free or forced convection, ferrohydrodynamic convection is not yet well characterized. A full understanding of the relationship between an imposed magnetic field, the resulting ferrofluid flow, and the temperature distribution is a prerequisite for the proper design and implementation of applications involving thermomagnetic convection. The literature variously assumes constant magnetic fields, does not completely represent the variation in the imposed field, or its descriptions are inaccurate, since the fields do not comply with the Maxwell's equations of electromagnetism. We address this by simulating two-dimensional forced convection heat transfer in a channel with a ferrofluid that is under the influence of a ...
In this letter we report a clear and unambiguous observation of the out-of-plane quadrupole magnetic field suggested by numerical simulations in the reconnecting current sheet in the Magnetic Reconnection Experiment (MRX). Measurements show that the Hall effect is large in collisionless regime and becomes small as the collisionality increases, indicating that the Hall effect plays an important role in collisionless reconnection.
Annealing of magnetostrictive Metglas foils, subsequently incorporated into laminated Metglas/Pb(Zr, Ti)O3 magnetoelectric (ME) composites, is shown to result in improved magnetic properties, as well as ME coefficients. Annealing of the foils at 350 ?C resulted in partial crystallization, without oxidation or magnetic cluster formation that would reduce the magnetization. Laminate composites made with these annealed Metglas foils had improved ME coefficients.
It is shown that recuperator in which the thermal energy of particles is transformed into electric oue under drift in crossed fields is naturally coupled with dragontype magnetic confinement system, so the recuperation process can be initiated in the dragon magnetic field. A number of questions occuring under analysis of recuperator-dragon system is considered, including the dynamics of particle transfer to the recuperator, the share of particles entering the recuperator, the effect of rotational transform and the recuperation efficiency.
Some applications of magnetic resonance in coal liquefaction research described briefly are: (1) investigation of the nature of carbon deposits on used coal-liquefaction catalysts, (2) determination of the fate of hydrogen during coal liquefaction, and (3) observation of transient free radicals during coal pyrolysis. The first two applications make use of cross-polarization /sup 13/C magnetic resonance combined with magic angle spinning, and the third application is an electron spin resonance study. (BLM)
The conductance in ferromagnetic Ni nano-wire is quantized in units of 2e{sup 2}/h in the absence of magnetic field, while the units switch to e{sup 2}/h in the magnetic field. The fractional units of 0.7e{sup 2}/h and 1.4e{sup 2}/h with and without magnetic field appear under the application of high bias-voltage. The spin polarization and bias-voltage play an important role in the electric conduction.
Here, we consider a recent paper concerned with magnetic braking by induced currents (Ireson and Twidle 2008 Eur. J. Phys. 29 745-51). Our objective is to elucidate why measurement of speed in which a magnet is dropped through a non-ferromagnetic conductive tube depends on its geometry in a non-monotonic way, which was not clearly explained by the authors. (letters and comments)
Although a large number of studies on effects of magnetic fields on living organisms was reported, no definite results were obtained in many cases because the related conditions are non-uniform and uncertain, such that the uniform magnetic space is smaller than test samples, and temperature control is insufficient. Therefore, the present study developed a microorganism cultivation system that is applied with a 7-T superconducting magnet. This system has the following features: it generates homogeneous magnetic fields of 0.5 to 7 T {plus_minus} 0.5% in the space with a diameter of 100 mm and a length of 200 mm in a normal temperature bore (with a diameter of 160 mm); it can cultivate microorganisms aerobically at temperatures of 10 to 70{degree}C {plus_minus} 0.1{degree}C; it can perform the cultivation simultaneously with a control cultivation in a small magnetic field weaker than ...
We present a formulation of ab initio electronic structure calculations in a finite magnetic field, which retains the simplicity and efficiency of techniques widely used in first principles molecular dynamics simulations, based on plane-wave basis sets and Fourier transforms. In addition we discuss results obtained with this method for the energy spectrum of interacting electrons in quantum wells, and for the electronic properties of dense fluid deuterium in a uniform magnetic field.
The mammalian placenta consists of different trophoblast cell types that assist in the variety of functions required for the maintenance of pregnancy. In rodents, labyrinthine trophoblasts of the placenta are especially important, because they are capable of differentiating into fused labyrinthine cells, which form the feto-maternal exchange surface. Even though the molecular signals triggering labyrinthine trophoblast differentiation are poorly understood, transforming growth factor-b (TGF-b) has been shown to be present in the placental environment and alter trophoblast development. In this study, we investigated the effects of TGF-b on the differentiation of the labyrinthine trophoblast stem cell lines SM10 and HRP-1. RT-PCR analyses demonstrated that while the molecular expression of l...
Previous research demonstrates that we tend to derogate individuals who are perceived to be in a social relationship with stigmatized persons. Two experiments examined whether this phenomenon also occurs for individuals seen in the presence of an obese person and whether a social relationship is necessary for stigmatization to spread. The results from both experiments revealed that a male job applicant was rated more negatively when seen with an overweight compared to a normal weight female and that just being in the mere proximity of an overweight woman was enough to trigger stigmatization toward the male applicant. Experiment 2 examined possible moderating effects of the proximity finding. Applicants seated next to heavy (vs. average weight) individuals were denigrated consistently regardless of the perceived depth of the relationship, the participant's anti-fat attitudes or gender, and whether or not positive information was presented concerning the woman. The ...
The Gigabit Link Interface Board (GLIB) is an evaluation platform and an easy entry point for users of high speed optical links in high energy physics experiments. Its intended use ranges from optical link evaluation in the laboratory to control, triggering and data acquisition from remote modules in beam or irradiation tests. The GLIB is an FPGA-based Advanced Mezzanine Card (AMC) conceived to serve a small and simple system residing either inside a Micro Telecommunications Computing Architecture (?TCA) crate, or on a bench with a link to a PC. This paper presents the architecture of the GLIB, its features as well as examples of its use in different setups.
This paper describes an experiment which has been performed with a somewhat different philosophy in its approach as compared to previous work. (a) The trigger threshold energy was increased by more than a factor of ten on previous experiments reducing the dilution effect of many lower energy showers known not to produce tachyons. 1673 shower were recorded. (b) The exposure time was made longer than previous experiments in order to obtain a reasonably large statistical sample at the higher threshold. Observations were made between February 1979 and June 1980, the total live time being 9768 hours. (c) Records of the detector output amplitude for the 480#mu#s lead time were integrated point by point as is sometimes done in radio astronomy, this gives the integrated energy deposition within the detector.
We present a detailed analysis of the self-organization phenomenon in which the stylized facts originate from finite size effects with respect to the number of agents considered and disappear in the limit of an infinite population. By introducing the possibility that agents can enter or leave the market depending on the behavior of the price, it is possible to show that the system self-organizes in a regime with a finite number of agents which corresponds to the stylized facts. The mechanism to enter or leave the market is based on the idea that a too stable market is unappealing for traders while the presence of price movements attracts agents to enter and speculate on the market. We show that this mechanism is also compatible with the idea that agents are scared by a noisy and risky market at shorter time scales. We also show that the mechanism for self-organization is robust with respect to variations of the exit/entry rules and that the attempt to trigger the ...
There is a rapidly growing need to evaluate sensor network functionality and performance in the context of the larger environment of infrastructure and applications in which the sensor network is organically embedded. This need, which is motivated by complex applications related to national security operations, leads to a paradigm fundamentally different from that of traditional data networks. In the sensor networks of interest to us, the network dynamics depend strongly on sensor activity, which in turn is triggered by events in the environment. Because the behavior of sensor networks is sensitive to these driving phenomena, the integrity of the sensed observations, measurements and resource usage by the network can widely vary. It is therefore imperative to accurately capture the environmental phenomena, and drive the simulation of the sensor network operation by accounting fully for the environment effects. In this paper, we illustrate the strong, intimate ...
An evaluation of Enova's heating program is presented. The central point was to evaluate to which degree Enova's heating program had resulted in increased supply of renewable energy for heating purposes to the Norwegian energy system. Main results are presented in part 1, chapter 1 to 5, while the facts and analyses behind the evaluation are presented in part 2, chapter I to VII. The main conclusion is that the program seen as one has had triggering effect on the market. The program has thus provided results in the form of increased supply of heating energy. Because of the project limitations and the lack of systematically documented baselines in the procedures, there are insecurities connected to the exact data registered. This makes quantification of the results difficult (ml)
The mass asymmetry of fragments from nuclear fission of heavy nuclei is reviewed. While mass asymmetry is a common and well-known phenomenon for low-energy fission of the lighter actinides, more recent experiments have demonstrated that, for the heaviest actinides, the mass distribution switches to a symmetric one. On the other hand, it has been discovered that, though for fissioning nuclei with mass numbers A< or [approx]225 the mass distribution is basically symmetric, an asymmetric component is clearly to be identified for nuclei down to the Pb-region. In the absence of a generally accepted dynamical theory of fission, the above experimental findings are discussed in terms of static energy considerations. Triggered from the outset by the structure of the potential energy surface at the saddlepoint, the energy balance at the scission point between the available energy (Q-value) of the reaction and the Coulomb and deformation energy of the nascent fragments is ...
The mass asymmetry of fragments from nuclear fission of heavy nuclei is reviewed. While mass asymmetry is a common and well-known phenomenon for low-energy fission of the lighter actinides, more recent experiments have demonstrated that, for the heaviest actinides, the mass distribution switches to a symmetric one. On the other hand, it has been discovered that, though for fissioning nuclei with mass numbers A< or #approx#225 the mass distribution is basically symmetric, an asymmetric component is clearly to be identified for nuclei down to the Pb-region. In the absence of a generally accepted dynamical theory of fission, the above experimental findings are discussed in terms of static energy considerations. Triggered from the outset by the structure of the potential energy surface at the saddlepoint, the energy balance at the scission point between the available energy (Q-value) of the reaction and the Coulomb and deformation energy of the nascent fragments is ...
Acidification is one of the most common and serious problems inducing process failure in anaerobic digesters. The production of volatile fatty acids (VFAs) mainly triggers acidic shock. However, little is known about the bacteria involved in the processes of acidogenic metabolism, such as fermentation and reductive acetogenesis. Here, the metabolic responses of a methanogenic community to the acidification and resulting process deterioration were investigated using transcriptional profiling of both the 16S rRNA and formyltetrahydrofolate synthetase (FTHFS) genes. The 16S rRNA-based analyses demonstrated that the dynamic shift of bacterial populations was closely correlated with reactor performance, especially with VFA accumulation levels. The pH drop accompanied by an increase in VFAs stim...
Delayed Afterdepolarization in Sinoatrial Node. Introduction: Recent evidence indicates that spontaneous sarcoplasmic reticulum Ca release and Na-Ca exchanger current activation contribute to the sinoatrial node (SAN) automaticity. These findings suggest that SAN activity may share mechanisms that underlie both automaticity and triggered activity. The aim of this study is to test the hypothesis that spontaneous, nonvoltage gated, intracellular Ca (Cai) elevation may induce delayed afterdepolarization (DAD) in intact SAN during isoproterenol infusion. Methods and Results: We simultaneously mapped Cai and membrane potential in 31 isolated Langendorff-perfused canine right atriums (RA). Isoproterenol increased heart rate and late diastolic Cai elevation (LDCAE) of the superior SAN, leading to...
Immune thrombocytopenic purpura (ITP), Guillain-Barre syndrome (GBS), and Hashimotos thyroiditis (HT) are autoimmune disorders caused by impaired self-tolerance mechanisms triggered by interaction between genetic and environmental factors. ITP is an immune-mediated destruction of platelets resulting in mucocutaneous bleeding, GBS is an ascending motor paralysis caused by an inflammatory demyelination of peripheral nerves, and HT is characterized by autoimmune-mediated destruction of the thyroid gland. The concurrent development of ITP and GBS has only rarely been reported in the literature, and GBS itself rarely occurs with other autoimmune disorders. We present a 21 year-old patient with known Hashimotos hypothyroidism that simultaneously developed GBS and ITP after an upper respiratory t...
Atrial fibrillation (AF) is common after coronary artery bypass grafting (CABG) and increases the morbidity and cost. Amiodarone reduces AF after CABG. Ranolazine, an antianginal agent, also prolongs atrial refractoriness and inhibits after depolarizations and triggered activity; effects that could decrease AF after CABG. The present study compared amiodarone versus ranolazine for the prevention of AF after CABG. A retrospective cohort study of patients undergoing CABG at Aspirus Hospital from June 2008 to April 2010. The patients received either amiodarone (400 mg preoperatively followed by 200 mg twice daily for 10 to 14 days) or ranolazine (1,500 mg preoperatively followed by 1,000 mg twice daily for 10 to 14 days). The primary end point was any identified AF after CABG. A total of 393 ...
Mammary glands are special tissue characterized by proliferation of the epithelium, during puberty and pregnancy and by programmed cell death, during involution. In this study, apoptosis was identified by TUNEL staining and then related to cell proliferation, as determined by Ki-67 staining. The apoptotic index was at its highest at 8 days of involution, whereas the proliferation index was at its highest during lactation. Caspase-3 was immunolocalised only in mast cells and along the basal membrane in the mammary tissue at -10 days from lambing, 150 days of lactation and at 8 days of involution. This finding could indicate that caspase-3 is not involved in sheep mammary gland apoptosis, but that other proteins - such as apoptosis inducing factor (AIF) - can trigger apoptosis, through the m...
In this work, we investigated self-heating related instability in polysilicon thin film transistors (poly-Si TFTs) fabricated on polyimide (PI) substrates. Indeed, when Joule heating becomes relevant, the temperature of the active layer can substantially rise, since the devices are fabricated on thermally insulating substrates. As a result, electrical instability is triggered and attributed to the generation of interface states, due to the Si-H bond breaking, and charge trapping into the gate insulator. In addition, by using 3-dimensional numerical simulations, coupling the thermodynamic and transport models, we analyzed the temperature distribution of the device under operating conditions and found that self-heating is more severe for devices fabricated on plastic substrates.