Energy Technology Data Exchange (ETDEWEB)

Magnetic fluids (MFs), prepared by chemical co-precipitation followed by double layer steric and electrostatic (combined) stabilization of magnetite nanoparticles dispersed in water, are presented. Several combinations of surfactants with different chain lengths (lauric acid (LA), myristic acid (MA), oleic acid (OA) and dodecyl-benzene-sulphonic acid (DBS)) were used, such as LA+LA, MA+MA, LA+DBS, MA+DBS, OA+DBS, OA+OA and DBS+DBS. Static light scattering, transmission electron microscopy, small angle neutron scattering, magnetic and magneto-rheological measurements revealed that MFs with MA+MA or LA+LA biocompatible double layer covered magnetite nanoparticles are the most stable colloidal systems among the investigated samples, and thus suitable for biomedical applications.

International Nuclear Information System (INIS)

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 ...

Energy Technology Data Exchange (ETDEWEB)

The new frustrated square-lattice system, Pb{sub 2}VO(PO{sub 4}){sub 2}, has been investigated using polarised neutron scattering. From these studies, made on powdered samples, we have determined the nature of the exchange interactions and the magnetic ordering for this novel quantum magnet. Quantum order from disorder occurs at low temperature, and the ground state observed below the Neel temperature T {sub N}{approx}3.7 K is a collinear antiferromagnet. At room temperature there are no magnetic correlations and it is possible to model the scattering with the V{sup 4+} magnetic form factor. However, at T{approx}20 K, a temperature well into the paramagnetic phase, magnetic correlations are observed, and these spin correlations have been modelled using a high-temperature series expansion. Ferromagnetic nearest-neighbour ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

The cross sections for proton-proton elastic scattering at Fermilab and ISR energies are investigated in the framework of the multiple constituent scattering formalism, including the contributions of the inelastic intermediate states. We find that the higher-order multiple scattering amplitudes are strongly suppressed due to the presence of the inelastic intermediate states. The calculated cross sections reproduce the high energy experimental data fairly well. (author).

International Nuclear Information System (INIS)

... magnetic susceptibility magnetization monocrystals neutron diffraction

Science.gov (United States)

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.

International Nuclear Information System (INIS)

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.

Energy Technology Data Exchange (ETDEWEB)

The magnetic pyrochlore Er{sub 2}Ru{sub 2}O{sub 7} has been studied with neutron scattering and susceptibility measurements down to a base temperature of 270 mK. For the low temperature phase in which the Er sublattice orders, new magnetic Bragg peaks are reported which can be indexed with integer (hkl) for a face centered cubic cell. Inelastic measurements reveal a wealth of crystal field levels of the Er ion and a copious amount of magnetic scattering below 15 meV. The three lowest groups of crystal field levels are at 6.7, 9.1 and 18.5 meV.

International Nuclear Information System (INIS)

... bcs theory electron reactions excited states form factors inelastic scattering

Science.gov (United States)

We analyze cross sections for quasielastic inclusive scattering of electrons on nuclei and show that the observed isolated peaks for relatively low Q{sup 2} are unique for the lightest targets. Focusing, in particular, on D and {sup 4}He, we investigate in two ways to what measure the above peaks can be allocated to nucleon-elastic processes. We first compute approximate upper limits for the nucleon-inelastic background in the quasielastic region due to inclusive {delta} excitation, and find those to be small. Far more precise is a semiphenomenological approach, where the dominance of nucleon-elastic processes is translated into a set of stringent requirements. We show that those are very well fulfilled for recent D data, and to a somewhat lesser extent for older D and {sup 4}He data. With knowledge of G{sub E,M}{sup p} and information on G{sub E}{sup n}, we then extract G{sub M}{sup n} and find agreement with values obtained by alternative ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

On the basis of the phenomenological model for baryon resonance production in lepton nucleon and lepton nucleus scattering we investigate to what extent quark hadron duality is applicable to the neutrino structure functions and how it compares with duality in electron scattering.

Energy Technology Data Exchange (ETDEWEB)

The wavefunction of a particle extends into the classically forbidden barrier region of the potential energy surface. The consequence of this partial delocalisation is the phenomenon of quantum tunnelling, an effect which enables a particle to penetrate a potential barrier of magnitude greater than the energy of the particle. The tunnelling probability is an exponential function of the particle mass. The effect is therefore an important contribution to the behaviour of light atoms, in particular the proton. The hydrogen bond has long been appreciated to be an essential component of many biological and chemical systems, and the proton transfer reaction in the hydrogen bond is fundamental to many of these processes. The proton behaviour in the hydrogen bonds of benzoic acid, acetylacetone and calix-4-arene has been studied. A variety of techniques, both experimental and computational, were adopted for the study of the three hydrogen bonded systems. The complementary spectroscopic ...

International Nuclear Information System (INIS)

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)

International Nuclear Information System (INIS)

The magnetic excitations of the Kondo compound CePd_2Si_2 below its Neel temperature (T_N = 10 K) have been studied by inelastic neutron scattering. At T = 1.6 K the data are best represented by two dispersive inelastic modes. Their linewidth (#propor to# 0.5 meV) indicates substantial broadening, which is ascribed to Kondo-type local fluctuations. (orig.).

International Nuclear Information System (INIS)

The magnetic scattering spectra of RAgSb_2 (R = Ho, Er, Tm) intermetallic compounds are measured and their crystal electric field parameters are determined using inelastic neutron scattering. It is revealed that the ground state is a nonmagnetic singlet for the HoAgSb_2 compound, a Kramers doublet with a strongly anisotropic g factor for the ErAgSb_2 compound, and a quasi-doublet (random doublet) characterized by an extremely anisotropic g factor for the TmAgSb_2 compound. The exchange interaction is estimated in the molecular field approximation. The magnetic properties of the RAgSb_2 compounds are analyzed in terms of the energy level schemes and eigenfunctions determined in this study. The calculated anisotropic magnetic susceptibilities for all compounds are in good agreement with the experimental data obtained for single crystals.

International Nuclear Information System (INIS)

The effect that different chemical and physical atomic environments can have on the relative intensities of radiative electron transitions from the filling of K shell vacancies was investigated. The method used involved the detection of photoionization induced X-ray fluorescence. An experimental system based on a hyper pure germanium detector (HPGE) was used to measure the relative K-L and K-M X-ray yields from the photofluorescence of a series of lanthanide elements and compounds. A background subtraction and peak integration strategy was employed which accounted for scattering in the samples and scattering of the flux from the radioisotope photoionization sources. Analysis of the data resulted in a tabulation of relative K/sub #beta#//K/sub #alpha#/ X-ray intensity ratios. The measured relative K/sub #beta#//K/sub #alpha#/ X-ray intensity ratios were compared to the calculated values predicted by the theoretical ...

International Nuclear Information System (INIS)

Obtained experimental data on integral cross sections (ICS) of inelastic scattering of 50.5 MeV #alpha# particles with the excitation of "6","7Li, "9Be, "1"2","1"3C, "1"4C, "1"4N, "2"0Ne, "2"4Mg, "2"8Si nucleus low-lying energy levels are discussed. Regularities, detected in the behaviour of ICS forward scattering for 20-90 deg angles and backscattering for 90-160 deg angles for the target-nucleus under investigation are considered. Effect of reaction open channel number on #alpha#-particle scattering ICS where n,p,d- and #alpha#-channels were considered as the main channels for all the target-nuclei, is discussed. Dependence of #alpha#-particle scattering ICS on the target-nucleus level excitation energy and dependences of reaction open channel number on the channel spin, calculated for 50.5 MeV #alpha# particles and different target nuclei are shown in the diagrams. It is noted ...

Energy Technology Data Exchange (ETDEWEB)

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 ...

Energy Technology Data Exchange (ETDEWEB)

We have performed inelastic neutron scattering (INS) experiments on CeRh{sub 3}B{sub 2} at various temperatures to obtain direct information on the crystal electric field (CEF) in this compound, which exhibits some very peculiar magnetic properties for a Ce system: it is ferromagnetic with an unusually high Curie temperature (115 K), which contrasts with a strongly reduced and anisotropic magnetization (0.4 {mu}{sub B}/fu within the c-plane of the hexagonal structure). Measurements with high incident energies show only one well defined magnetic excitation around 150 meV, its exact position varying with the temperature. These results, combined with our previous data of magnetization and magnetic form factor, have permitted us to determine the CEF energy level scheme taking into account the two J multiplets of the Ce{sup 3+} ion. Information on the ground state ...

Energy Technology Data Exchange (ETDEWEB)

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.

Scientific Electronic Library Online (English)

Abstract in english We consider the three dimensional electromagnetic inverse scattering problem of determining information about a buried coated object from a knowledge of the electric and magnetic fields measured on the surface of the earth corresponding to time harmonic electric dipoles as incident fields. We assume that the buried object is a perfect conductor that is (possibly) partially coated by a thin dielectric layer. No a priori assumption is made on the extent of the coating, i.e. (more) the object can be fully coated, partially coated or not coated at all. We present an algorithm based on the linear sampling method and reciprocity gap functional for reconstructing the shape of the scattering obstacle together with an estimate of the surface impedance of the coating.

Science.gov (United States)

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.

Energy Technology Data Exchange (ETDEWEB)

The development of high energy (> 150 keV) neutral beams for heating and fueling magnetic fusion devices depends on the ability to produce well-collimated negative ion beams. The double capture charge-exchange technique is a known, scalable method. In order to maximize the overall efficiency of the process and to achieve the desired beam characteristics, it is necessary to examine the optical qualities of the beams as well as the total efficiency of beam production. A combined modeling and experimental study of the angular scattering effects in negative ion formation and loss processes has therefore been undertaken.

Energy Technology Data Exchange (ETDEWEB)

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 ...

International Nuclear Information System (INIS)

Many mechanical parts are subjected to stresses and strains that may eventually lead to their failure. In order to prevent the costly delays associated with equipment down-time, many parts have to be tested for weaknesses and defects when machinery is constructed or dismantled for maintenance. These procedures are known as Non-Destructive Testing (NDT) methods. Five types of non-destructive testing methods routinely used are radiographic testing, ultrasonic testing, magnetic particle inspection, liquid penetrant testing and eddy current testing. Out of these five techniques industrial radiography plays an important role in non-destructive testing to reveal interior defects in materials. In radiography almost two-thirds of the radiation reaching the film is scattered radiation which does not form the image of defects. Scattered radiation generated inside and outside a material has a very large effect on sensitivity of flaw ...

CERN Document Server

Neutrino emission drives neutron star cooling for the first several hundreds of years after its birth. Given the low energy ($\\sim$ keV) nature of this process, one expects very few nonstandard particle physics contributions which could affect this rate. Requiring that any new physics contributions involve light degrees of freedom, one of the likely candidates which can affect the cooling process would be a nonzero magnetic moment for the neutrino. To illustrate, we compute the emission rate for neutrino pair bremsstrahlung in neutron-neutron scattering through photon-neutrino magnetic moment coupling. We also present analogous differential rates for neutrino scattering off nucleons and electrons that determine neutrino opacities in supernovae. Employing current upper bounds from collider experiments on the tau magnetic moment, we find that the neutrino emission rate can exceed the ...

International Nuclear Information System (INIS)

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.

International Nuclear Information System (INIS)

The neutron elastic magnetic form factor was extracted from quasielastic electron scattering on deuterium over the range Q2=1.0-4.8 GeV2 with the CLAS detector at Jefferson Lab. High precision was achieved with a ratio technique and a simultaneous in situ calibration of the neutron detection efficiency. Neutrons were detected with electromagnetic calorimeters and time-of-flight scintillators at two beam energies. The dipole parametrization gives a good description of the data.

CERN Document Server

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.

Energy Technology Data Exchange (ETDEWEB)

The magnetic excitations of the Kondo compound CePd{sub 2}Si{sub 2} below its Neel temperature (T{sub N} = 10 K) have been studied by inelastic neutron scattering. At T = 1.6 K the data are best represented by two dispersive inelastic modes. Their linewidth ({proportional to} 0.5 meV) indicates substantial broadening, which is ascribed to Kondo-type local fluctuations. (orig.).

Energy Technology Data Exchange (ETDEWEB)

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 ...

International Nuclear Information System (INIS)

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.).

International Nuclear Information System (INIS)

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 ...

Energy Technology Data Exchange (ETDEWEB)

The effect of nuclear scattering on the suprathermal fusion probability of recoiling d-t nuclei under the impact of fusion products, a 14.1-MeV neutron and a 3.5 MeV alpha particle, in thick pellets is investigated with the help of the Boltzmann-Fokker-Planck equation. Although the suprathermal fusion from alpha-particle recoils is quite small, the one originating from neutron recoils is considerable.

Energy Technology Data Exchange (ETDEWEB)

We present a phenomenological model of the quark-hadron transition in neutrino-nucleon scattering. Using recently extracted weak nucleon transition form factors, we investigate the extent to which local and global quark-hadron duality is applicable in the neutrino F{sub 1}, F{sub 2} and F{sub 3} structure functions, and contrast this with duality in electron scattering. Our findings suggest that duality works relatively well for neutrino-nucleon scattering for the F{sub 2} and F{sub 3} structure functions, but not as well for F{sub 1}. We also calculate the quasi-elastic, resonance and deep inelastic contributions to the Adler sum rule, and find it to be satisfied to within 10% for 0.5 < Q{sup 2} < 2 GeV{sup 2}.

Science.gov (United States)

Recent proposals have shown that a quantum degenerate gas of alkaline earth atoms can be used for a number of novel quantum computing and quantum simulation experiments. Strontium is a good candidate for such experiments because it can be controlled with high precision, as demonstrated in recent atomic clock experiments. Unfortunately, the small scattering length of strontium is not amenable to evaporative cooling techniques that are used to reach quantum degeneracy. Furthermore, increasing the scattering length of alkaline earths with a magnetic Feshbach resonance is not possible due to their spinless electronic ground state configuration. However, recent theoretical and experimental work suggests the possibility of changing scattering lengths in alkaline earths with laser light. Using this optical Feshbach resonance near strontium's narrow ^1S0->^3P1 intercombination transition might allow its ...

Energy Technology Data Exchange (ETDEWEB)

The main subject of this thesis is the study of the hardronic final state in deep-inelastic electron-proton scattering. Theexperiment described in this thesis is performed with such a high resolution that the substructure of the proton is probed by the electron beam with a resolution of less than 10{sup -15} cm. (orig./HSI).

International Nuclear Information System (INIS)

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 ...

International Nuclear Information System (INIS)

... cambrian period geologic history geology gondwana granites latin america

Energy Technology Data Exchange (ETDEWEB)

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.

Energy Technology Data Exchange (ETDEWEB)

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)

International Nuclear Information System (INIS)

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 ...

International Nuclear Information System (INIS)

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 ...

Energy Technology Data Exchange (ETDEWEB)

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.)

Energy Technology Data Exchange (ETDEWEB)

A study of the ..pi..1g/sub 9/2/ orbit size in /sup 88/Sr, /sup 90/Zr, and /sup 92/Mo is presented. The rms radius for the point-proton density is extracted by studying transitions to 8/sup +/ states in these nuclei. The radii are consistently larger than a value determined in a magnetic electron scattering experiment on /sup 93/Nb. A qualitative discussion of the ground state occupation of the ..pi..1g/sub 9/2/ orbit based on the transition amplitudes to the 8/sup +/ states is given.

Science.gov (United States)

The kinetic and guiding center fluid theories of high-..beta.. plasma containment in mirror machines have been developed in a number of self-consistent models. The geometrical effects of magnetic field and ambipolar potential variation have been incorporated in a bounce-averaged Fokker-Planck code which shows that the square-well model somewhat overestimates the n tau and ..beta.. achievable in a mirror field. Simple analytic approximations to the resulting pressure profiles have been incorporated in three-dimensional fluid-equilibrium codes which show the effect of coil geometry on the maximum ..beta... Strongly curved vacuum fields allow higher ..beta.., but short plasmas in weakly curved fields tend to reverse the curvature locally before the mirror-mode limit is reached. Adiabaticity of particle orbits is described in terms of general formulas, applicable in high-..beta.. plasma equilibria, and is shown to break down close to the mirror-mode limit. Two ...

Energy Technology Data Exchange (ETDEWEB)

Heusler alloys are considered as interesting ferromagnetic electrode materials for magnetic tunnel junctions, because of their high spin polarization. We, therefore, investigated the micromagnetic properties in a prototypical thin film system comprising two different Heusler phases Co{sub 2}MnSi (CMS) and Co{sub 2}FeSi (CFS) separated by a MgO barrier. The magnetic microstructure was investigated by X-ray photoemission electron microscopy (XPEEM). We find a strong influence of the Heusler phase formation process on the magnetic domain patterns. SiO{sub 2}/V/CMS/MgO/CFS and SiO{sub 2}/V/CFS/MgO/CMS trilayer structures exhibit a strikingly different magnetic behavior, which is due to pinhole coupling through the MgO barrier and a strong thickness dependence of the magnetic ordering in Co{sub 2}MnSi.

International Nuclear Information System (INIS)

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 ...

Energy Technology Data Exchange (ETDEWEB)

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 ...

Energy Technology Data Exchange (ETDEWEB)

In this work, we have investigated the capability of different bimetallic nanoparticle alloy combinations to be used in fibre optic temperature sensing based on the technique of surface plasmon resonance (SPR). The metals considered for the present analysis are silver, gold and aluminium. The analysis is derived mainly from the thermo-optic effect along with some fundamental concepts of metal optics such as surface scattering, phonon-electron scattering and electron-electron scattering. The performance of the sensor with three different bimetallic nanoparticle alloy combinations is evaluated and compared, numerically, in terms of its sensitivity and accuracy. On the basis of the comparison and some logistic criterion, we predict the best possible bimetallic alloy combination along with a requisite alloy composition ratio that simultaneously provides higher values of both sensitivity and accuracy which ...

British Library Electronic Table of Contents (United Kingdom)

Purpose To investigate the influence of timolol maleate 0.5% gel-forming solution and brinzolamide 1% ophthalmic suspension on contrast sensitivity, ocular higher-order aberration (HOA), and corneal surface light scattering. Design Prospective, comparative study. Participants Forty normal volunteers were enrolled in this study. Methods We evaluated contrast sensitivity, ocular HOA, and corneal light scattering before and 2, 5, 10, and 15 minutes after instillation of antiglaucoma eyedrops. Contrast sensitivity function was assessed with the CSV-1000RN chart (Vector Vision Co., Greenville, OH). Higher-order aberration was measured for a 4-mm pupil using the Hartmann-Shack aberrometer (KR-9000PW; Topcon, Tokyo, Japan). Corneal surface light scattering was quantitatively evaluated by using th...

CERN Document Server

The scattering and recombination processes between two triplet excitons in conjugated polymers are investigated by using a nonadiabatic evolution method, based on an extended Su-Schrieffer-Heeger model including interchain interactions. Due to the interchain coupling, the electron and/or hole in the two triplet excitons can exchange. The results show that the recombination induces the formation of singlet excitons, excited polarons and biexcitons. Moreover, we also find the yields of these products, which can contribute to the emission, increase with the interchain coupling strength, in good agreement with results from experiments.

International Nuclear Information System (INIS)

The problem of search for new materials for spectrally positioned laser sources, which is central for modern photonics, is discussed. The use of the stimulated Raman scattering effect in crystals offers a highly efficient way to the design of such sources. The recent results of investigations into this effect for a large number of various types of crystalline materials are presented. The most promising compounds, as regards the realisation of different laser operation modes, are considered, including calcium, strontium, barium and lead molybdates and tungstates. Several examples of functioning efficient lasers based on novel materials exhibiting the stimulated Raman light scattering effect are given.

Energy Technology Data Exchange (ETDEWEB)

Many nondestructive beam position monitors are known. However, these devices can not be used for DC particle beam diagnostics. We investigated a method of beam diagnostics applicable for the operative control of DC high power e-beam inside closed waveguide. A design of the detector for determination of{open_quote} center of mass {close_quote} position of DC particle beam was developed. It was shown that the monitor can be used as a nondestructive method for the beam position control in resonators. Magnetic field of the particle beam outside a resonator is used. The detector consists of the steel yokes and magnetic field sensors. The sensors measure magnetic fluxes in the steel yokes fixed outside the resonator. When the particle beam changes its position, these magnetic fluxes also change. Beam displacement sensitivity of the monitor depends on the steel yoke dimensions. The ...

Energy Technology Data Exchange (ETDEWEB)

The neutron elastic magnetic form factor G{sub M}{sup n} has been extracted from quasielastic scattering from deuterium in the CEBAF Large Acceptance Spectrometer, CLAS [B. Mecking et al., Nucl. Inst. and Meth. A 503 (2003) 513]. The kinematic coverage of the measurement is continuous over a broad range, extending from below 1 GeV{sup 2} to nearly 5 GeV{sup 2} in four-momentum transfer squared. High precision is achieved by employing a ratio technique in which most uncertainties cancel, and by a simultaneous in-situ calibration of the neutron detection efficiency, the largest correction to the data. Preliminary results are shown with statistical errors only.

CERN Document Server

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.

International Nuclear Information System (INIS)

The most propagated mechanisms of stimulated radiation of electron beam such as Cherenkov one-particle and collective effects, ondulator and magnetic bremsshrahlung radiations, Doppler anomalous effect, Thompson and Raman scattering and radiation are discussed. Relation of spontaneous radiation mechanisms of individual electron and stimulated radiation effects in electron beams has been elucidated, grounds of linear electrodynamics of radiative beam instabilities are stated, and main mechanisms of their nonlinear stabilization are elucidated as well. Various simulated processes in electron beams are considered from the unique point of view using a simple mathematical apparatus and such physical laws as conservation and Newton laws.

International Nuclear Information System (INIS)

R_2PdSi_3 compounds have been found to exhibit rich magnetic phenomena arising from the interplay between RKKY interaction, crystal electric field effects and geometric frustration due to the derived hexagonal AlB_2 structure. The observed crystallographic superstructure further complicates the CEF level scheme. Inelastic neutron scattering measurements on single crystals of Tm_2PdSi_3 and Er_2PdSi_3 have been performed at the cold triple axis spectrometer PANDA in FRM-II. Both compounds order antiferromagnetically at T_N=7 K and 2.1 K respectively; Er_2PdSi_3 undergoes a second phase transition at T_2=2 K. Several low lying CEF excitations (below 10 meV) were observed. The intensity of the lowest excitation show strong directional dependence (in HK0 plane for Er_2PdSi_3 and in HHL plane for Tm_2PdSi_3), from which the details of the transitional matrix could be deduced. Measurements in magnetic fields up to 13 T show ...

British Library Electronic Table of Contents (United Kingdom)

The present paper investigates the peristaltic transport of a couple stress fluid in an asymmetric channel with the effect of the induced magnetic field. The exact solutions of momentum and the magnetic field equations have been calculated under the assumptions of long wave length and low but finite Reynolds number. The expression for pressure rise has been computed numerically using mathematics software Mathematica. The graphical results have been presented to discuss the physical behavior of various physical parameters of interest. Finally, the trapping phenomena have been discussed for various physical parameters.

Science.gov (United States)

Self-magnetically insulated, high-voltage transmission lines are used in inertial confinement fusion particle accelerators in order to transmit power from the vacuum insulator to the diode. This paper describes a time-dependent 2-D code (MITL) for calculating (for planar or triplate geometries) the motion of test electrons through the tapered input or output convolutes of such lines. MITL results show that the electron canonical momentum in the direction of the flow changes as the electron passes through the convoluted geometry; it is suggested that these electrons lead to losses observed in long self-magnetically insulated lines.

Energy Technology Data Exchange (ETDEWEB)

The baseline design for the SSC High Energy Booster (HEB) has dipole bending magnets with a 50 mm aperture. An analysis of the cryogenic heat load due to A.C. losses generated in the HEB ramp cycle are reported for this magnet. Included in this analysis are losses from superconductor hysteresis, yoke hysteresis, strand eddy currents, and cable eddy currents. The A.C. loss impact of 2.5 {mu}m vs. 6 {mu}m filament conductor is presented. A 60 mm aperture design is also investigated. 8 refs., 3 tabs.

International Nuclear Information System (INIS)

Elastic scattering of 27.2 MeV #alpha# particles on "4"0Ca has been investigated. Differential cross sections have been measured in the angular range from 10 deg to 175 deg in the lab. system. The theoretical analysis has proceeded from the proposition that the results of a calculation based on the optical model in the range of small angles (less than 20 deg for "4"0Ca) are independent of parameters and shape of the potential employed. Elastic scattering of #alpha# particles at angles up to 50 deg has been calculated using three sets of the optical potential parameters in the energy range 23.37-28.92 MeV. In the range of small angles a rather similar behaviour of the calculated curves can be observed whereas in the range of medium and large angles these curves behave very differently. The success in the reproduction of the angular distributions for the entire energy range is indicative of the weak energy dependence of the ...

Energy Technology Data Exchange (ETDEWEB)

The production method of the elastic composite containing ferrous particles and titanium barium particles dispersed in the porous silicone matrix is described in this article. Since it contains ferrous and titanium barium particles, this composite shows magnetorheological and also electrorheological properties. The electrostriction of composite samples in the electric field with maximal intensity 1.5x10{sup 6} V/m was investigated. The magnetostriction in the magnetic field with maximal induction 1 T was also investigated. It was found that samples elongate with increased electric field intensity, and the magnetic field induction was detected. By increasing the samples' elongation with increase of ferrous particles, titanium barium particles and pores number were also detected. In the investigated division of the electric and magnetic field the ...

Energy Technology Data Exchange (ETDEWEB)

The determination of ratio of neutron over proton matrix elements by inelastic proton scattering, for 0{sup +}{yields}2{sup +} transitions, is investigated via the comparison between experimental data and theoretical calculations. Calculations into the context of a macroscopic and a microscopic description are performed for a wide mass range nuclei: {sup 18}O, {sup 30}Si, {sup 32,34}S, {sup 48}Ca, {sup 88}Sr, for which these ratios were determined previously with an independent technique. At that point the choice of the theoretical model may be very critical. It is thus the purpose of this investigation to point out the most suitable model. It is found that in general both theoretical models can be employed for the reliable determination of neutron over proton matrix element ratios.

International Nuclear Information System (INIS)

Pacini (1973) has considered basic theoretical expectations regarding the magnetic dipole radiation and unipolar induction of pulsars, taking into account observational results. The present investigation is concerned with the difference between the two braking mechanisms. Attention is also given to a statistical study involving a comparison of the two braking mechanisms with observations. The study makes use of the observational data for the distribution of apparent beamwidth, and a geometrical method. The obtained results agree with the theory of magnetic dipole radiation.

International Nuclear Information System (INIS)

Magnetic properties of layer ferromagnets against the thickness are investigated. Two new compounds served for studies: Bisub(6)Tisub(2)Nbsub(0,5)Fesub(2,5)Osub(18) and Bi_7Ti_3Fe_3O_2_1. The Moessbauer effect and the magnetic susceptibility measurements were applied in the experiment. The Faraday method was used in magnetic measurements in fields from 1 to 9,5 kOe. The results of Moessbauer measurements show that temperature dependence of the spectra is typical for compounds with superparamagnetic properties. The magnetic fields Hsub(n) on Fe"5"7 nuclei in Bisub(6)Tisub(2)Nbsub(0,5)Fesub(2,5)Osub(18) and Bi_7Ti_3Fe_3O_2_1 are similar and equal to 520+-10 kOe. Therefore it may be concluded that relaxation times of nuclear spins in these compounds are equal or close to each other. The lines of quadrupole splitting appear in spectra together at 20 K. The results of ...

International Nuclear Information System (INIS)

The crystal structure, lattice strain due to the antiferromagnetic ordering, and magnetic form factor in the itinerant 5f compounds UTGa_5 (T=Ni, Pd, Pt) have been studied by neutron scattering. High-resolution powder diffraction revealed that the tetragonality of the U-Ga layers increases down to the series of the transition metal element T. The integrated intensities of the antiferromagnetic reflections can be well explained with the Neel-type structure for UNiGa_5, whereas UPtGa_5 has the antiferromagnetic stacking of the ferromagnetically ordered uranium moments in the c plane. In both compounds the uranium moments orient along the c axis with moments of 0.75(5) and 0.32(5) #mu#_B for UNiGa_5 and UPtGa_5, respectively. No magnetic peak could be observed in the powder diffraction pattern of UPdGa_5 due to the small magnetic moment less than the experimental sensitivity. The orbital contributions in ...

British Library Electronic Table of Contents (United Kingdom)

Purpose - The purpose of this paper is to investigate the accuracy of different force calculation methods and their impact on mechanical deformations. For this purpose, a micrometer scaled actuator is considered, which consists of a micro-coil and of a permanent magnet (PM) embedded in a deformable elastomeric layer. Design/methodology/approach - For the magnetic field evaluation a hybrid numerical approach (finite element method/boundary element method (FEM/BEM) coupling and a FEM/BEM/Biot-Savart approach) is used, whereas FEM is implemented for the mechanical deformation analysis. Furthermore, for the magneto-mechanical coupling several force calculation methods, namely the Maxwell stress tensor, the virtual work approach and the equivalent magnetic sources methods, are considered and co...

British Library Electronic Table of Contents (United Kingdom)

In this study structural and magnetic character of the expanded austenite phase (gN) layer formed on a medical grade CoCrMo alloy by a low-pressure Radio-Frequency plasma nitriding process was investigated. The formation of the expanded austenite phase is facilitated at a substrate temperature near 400^oC for 1, 2, 4, 6 and 20h under a gas mixture of 60% N2-40% H2. The magnetic state of the gN layers was determined by a surface sensitive technique, magneto-optic Kerr effect (MOKE), and with a scanning probe microscope in magnetic force mode (MFM). Strong evidence for the ferromagnetic nature of the gN-(Co,Cr,Mo) phase is provided by the observation of stripe domain structures and the hysteresis loops. The ferromagnetic state for the gN phase observed here is mainly linked to large lattice ...

Energy Technology Data Exchange (ETDEWEB)

The cross-over from a magnetically ordered to a non-magnetic spin liquid state has been investigated in a series of resistance measurements under hydrostatic pressures of up to 30 kbar and at temperatures down to below 200 mK in the heavy fermion antiferromagnet CePd{sub 2}Si{sub 2}. The electrical resistivity changes dramatically with increasing pressure. Near the critical pressure, at which the magnetic ordering temperature is extrapolated to zero, it exhibits a quasi-linear variation over two orders of magnitude in temperature. This non-Fermi liquid form of {rho}(T) extends down to the onset of a new superconducting transition below 430 mK. (orig.).

Energy Technology Data Exchange (ETDEWEB)

High-field magnetization properties of single crystalline CeRh{sub 2}Si{sub 2} and CePd{sub 2}Si{sub 2} were investigated. Two-step metamagnetic transition (H{sub c1}=25.4 T and H{sub c2}=26.0 T) was observed in the case of CeRh{sub 2}Si{sub 2}, whereas no anomaly was found in the magnetization process of CePd{sub 2}Si{sub 2} up to 28 T. The mean field analysis has shown that CeRh{sub 2}Si{sub 2} is quite anisotropic compared to CePd{sub 2}Si{sub 2}, which results in the sharp contrast between the magnetization processes of the two compounds.

International Nuclear Information System (INIS)

Ferrite of system, namely Ni_1_-_xZn_xFe_2O_4 with x = (0.0, 0.2, 0.4, 0.6, 0.8, 1.0), have been prepared by solid state reaction to investigate the effect of gamma rays irradiations using Co"6"0 source on the cation distribution, structural and magnetic properties. The unirradiated and irradiated samples were then subjected to characterization techniques such as X-ray diffraction, magnetization and AC susceptibility. The results of these characterizations are found to be different for irradiated from that of the pristine sample. The modifications in respect of irradiated samples are explained in terms of the ion-induced disorder. The important result of #gamma#-irradiation on the cation distribution, structural and magnetic properties is the change of ratio Fe"2"+/Fe"3"+. Possible reasons on the results are proposed.

International Nuclear Information System (INIS)

We investigate the effects of the velocity-dependent force on the magnetic form factors and magnetic moments of odd-Z nuclei. The form factors are calculated with the harmonic-oscillator wavefunctions. It is found that the contributions of the velocity-dependent force manifest themselves in the very large momentum transfer region (q?4 fm-1). In the low and medium q region the contributions of the velocity-dependent force are very small compared with those without this force. However, in the high-q region the contributions of the velocity-dependent force are larger than the normal form factors. The diffraction structures beyond the existing experimental data are found after the contributions of the velocity-dependent force are included. The formula of the correction to the single particle magnetic moment due to the velocity-dependent force is reproduced exactly in the long-wavelength limit (q=0) of the ...

UK PubMed Central (United Kingdom)

Natural abundance 13C solid-state nuclear magnetic resonance spectroscopy was used to investigate the effect of the incorporation of cholesterol on the dynamics of dimyristoylphosphatidylcholine (DMPC)...Full Text Available

UK PubMed Central (United Kingdom)

The purpose of this study was to investigate whether genetically determined properties of muscle metabolism contribute to the exceptional physical endurance of world-class distance runners. ATP, phosphocreatine,...Full Text Available

International Nuclear Information System (INIS)

... momentum transfer propagator scattering scattering amplitudes strong

International Nuclear Information System (INIS)

Results of an investigation of the weldability of compact hollow automobile parts are reported. The use of magnetically impelled arc butt (MIAB) welding for a piston rod (OD_22_mm x 2.2_mm thickness), a shock-absorber (OD 40 mm x 2.2 mm) and a torque rod (OD 34 mm x 6 mm) has been investigated. Metallographic examination and comprehensive mechanical testing has been conducted to demonstrate the effectiveness of the method for joining of these types of automobile components

Energy Technology Data Exchange (ETDEWEB)

Experimental investigations are presented which demonstrate that the weak ferromagnets are special materials of a larger group of magnets which exhibit two magnetic ordering structures. In weak ferromagnets the main order is antiferromagnetic with a small ferromagnetic component existing in addition. On the other hand, materials in which other combinations of the two basic ordering structures coexist are also known. Common to all these non-collinear spin structures is that the moment components of the two magnetic structures are orthogonal. In the weak ferromagnets this orthogonality manifests already in the paramagnetic phase as a crossover from an isotropic to an anisotropic susceptibility with respect to the applied magnetic field: at high temperatures the antiferromagnetic Curie-Weiss law of the total moment is observed while for T->Tc crossover to a second Curie-Weiss ...

CERN Document Server

The X-ray spectra of some magnetized isolated neutron stars (NSs) show absorption features with equivalent widths (EWs) of 50 - 200 eV, whose nature is not yet well known. To explain the prominent absorption features in the soft X-ray spectra of the highly magnetized (B ~ 10^{14} G) X-ray dim isolated NSs (XDINSs), we theoretically investigate different NS local surface models, including naked condensed iron surfaces and partially ionized hydrogen model atmospheres, with semi-infinite and thin atmospheres above the condensed surface. We also developed a code for computing light curves and integral emergent spectra of magnetized neutron stars with various temperature and magnetic field distributions over the NS surface. We compare the general properties of the computed and observed light curves and integral spectra for XDINS RBS\\,1223 and conclude that the observations can be ...

British Library Electronic Table of Contents (United Kingdom)

Eddy current testing is one of the most widely used methods in non-destructive testing for the inspection of conductive materials. Numerical modelling of eddy current testing has emerged as an important approach alongside experimental studies. This paper investigates an application of numerical modelling and experimental study as a means of the quantitative non-destructive evaluation (QNDE) of defects in conductive samples. There are two methods of measuring eddy current response, more commonly by measuring the change in impedance of the eddy current probe coil, or as used in this work, by measuring the change in magnetic field directly using magnetic field sensors such as superconducting quantum interference devices, giant magneto resistance, or as in this case Hall sensors. Specifically,...

Energy Technology Data Exchange (ETDEWEB)

We investigate the possibility of observing strong interactions of longitudinally polarized weak vector bosons in the process {gamma}{gamma} {yields} ZZ at a photon linear collider. We make use of polarization of the photon beams and cuts on the decay products of the Z bosons to enhance the signal relative to the background of transversely polarized ZZ pairs. We find that the background overwhelms the signal unless there are strong resonant effects, as for instance from a technicolor analogue of the hadronic f{sub 2}(1270) meson.

International Nuclear Information System (INIS)

An approach to high energy nuclear reactions (relativistic nuclear physics) is developed on the basis of the quark-parton-flucton concept. The main assumptions underlying the known parton chain model are briefly reformulated, modified and generalized to the flucton case. This new model is used to investigate electron-nuclei and muon-nuclei inclusive reactions within the framework of quantum electrodynamics. The theoretical results are fitted well with existing data. (Auth.).

International Nuclear Information System (INIS)

This report summarizes the results and activities funded by this three-year award. The principal goal of this project was to determine the thermal conductivity in clusters of galaxies. Intracluster plasmas possess chaotic magnetic fields. Since charged particles are constrained to move primarily along magnetic field lines, the topology of intracluster magnetic fields slows particle diffusion relative to the non-magnetized case, thereby reducing the thermal conductivity. Our first approach to this problem was to employ the static-magnetic-field approximation. In reality, intracluster magnetic field lines are constantly moving, since they are advected by turbulent intracluster motions. The turbulent velocities, however, are much smaller than the rapid speeds of thermal electrons, which make the dominant contribution to the thermal conductivity. In the static-field ...

Energy Technology Data Exchange (ETDEWEB)

Effect of low-frequency pulsating magnetic field on the microstructure and magnetic properties of amorphous alloy Fe{sub 78}Si{sub 9}B{sub 13} 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{sub 78}Si{sub 9}B{sub 13}. 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 ...

International Nuclear Information System (INIS)

During their catalytic cycle, proteins involved in biological signal transduction undergo unexpectedly large conformational changes, which are at the core of their biological functioning. Until now it has been extremely difficult to obtain experimental insight into the nature of these conformational changes. Mathematical modeling and time-resolved X-ray crystallography have resulted in probable routes along which these conformational changes may take place, but so far this fundamental biological phenomenon has hardly been tackled experimentally. Here, we report on an attempt to observe structural changes in Photoactive Yellow Protein with time-resolved small-angle neutron scattering using diffractometer D22 at the high-flux reactor of the Institut Laue-Langevin, Grenoble, France

British Library Electronic Table of Contents (United Kingdom)

Non-linear optics encompasses a range of optical phenomena, including two- and three-photon fluorescence, second harmonic generation (SHG), sum frequency generation (SFG), difference frequency generation (DFG), third harmonic generation (THG), coherent anti-Stokes Raman scattering (CARS), and stimulated Raman scattering (SRS). The combined advantages of using these phenomena for imaging complex pharmaceutical systems include chemical and structural specificities, high optical spatial and temporal resolutions, no requirement for labels, and the ability to image in an aqueous environment. These features make such imaging well suited for a wide range of pharmaceutical and biopharmaceutical investigations, including material and dosage form characterisation, dosage form digestion and drug rele...

Energy Technology Data Exchange (ETDEWEB)

Energy flows in deep inelastic electron-proton scattering are investigated at a centre-of-mass energy of 296 GeV for the range Q{sup 2}{>=}10 GeV{sup 2} using the ZEUS detector. A comparison is made between events with and without a large rapidity gap between the hadronic system and the proton direction. The energy flows, corrected for detector acceptance and resolution, are shown for these two classes of events in both the HERA laboratory frame and the Breit frame. From the differences in the shapes of these energy flows we conclude that QCD radiation is suppressed in the large-rapidity-gap events compared to the events without a large rapidity gap. (orig.)

International Nuclear Information System (INIS)

The purpose of this investigation is to show that resource to anisotropic compression along a magnetic field is not a necessary condition for star formation within large collapsing interstellar gas clouds. Although such a scenario would certainly eliminate the magnetic field and angular momentum problems associated with isotropically collapsing clouds, it is believed there is sufficient observational theoretical evidence to warrant the present study of magnetically braked, isotropically collapsing gas clouds. It is not attempted to disprove the hypothesis of anisotropic compression, but to offer instead, a reasonable alternative. Angular momentum transfer from magnetically braked, cool interstellar gas clouds of 10"2, 10"3 and 10"4 times the mass of the sun is examined. Magnetic torques acting on a contracting, rotating cloud, permeated by a frozen-in ...

CERN Document Server

We have monitored a Type II outburst of the Be/X-ray binary MXB 0656-072 in a series of pointed RXTE observations during October through December 2003. The source spectrum shows a cyclotron resonance scattering feature at 32.8 +/- 0.5 keV, corresponding to a magnetic field strength of (3.67 +/- 0.06) x 10^12 G and is stable through the outburst and over the pulsar spin phase. The pulsar, with an average pulse period of 160.4 +/- 0.4 s, shows a spin-up of 0.45 s over the duration of the outburst. From optical data, the source distance is estimated to be 3.9 +/- 0.1 kpc and this is used to estimate the X-ray luminosity and a theoretical prediction of the pulsar spin-up during the outburst.

Science.gov (United States)

The complete world set of parity-violating electron scattering data up to Q{sup 2}{approx}0.3 GeV{sup 2} is analyzed. We extract the current experimental determination of the strange electric and magnetic form factors of the proton, as well as the weak axial form factors of the proton and neutron, at Q{sup 2}=0.1 GeV{sup 2}. Within experimental uncertainties, we find that the strange form factors are consistent with zero, as are the anapole contributions to the axial form factors. Nevertheless, the correlation between the strange and anapole contributions suggest that there is only a small probability that these form factors all vanish simultaneously.

Energy Technology Data Exchange (ETDEWEB)

The purpose of the study was to optimise the technique employed for AP shoulder and lateral cervical spine examinations following an investigation into image quality, based on clinical assessment, and effective dose, calculated from patient entrance surface dose measurements. A study was therefore conducted in an attempt to determine whether the increased radiation dose to the patient following the introduction of an anti-scatter grid was justified by the level of improvement in image quality. The study, involving 100 patients, was able to demonstrate that the increase in radiation dose to the patient when using an anti-scatter grid for AP shoulder examinations is not justified by the improved image quality. A poor level of inter-rater reliability between the consultants scoring the lateral cervical spine images prevented a firm conclusion from being reached. The fact that all images were of diagnostic quality, however, ...

Energy Technology Data Exchange (ETDEWEB)

With respect to concept of resolution in seismic exploration using the reflection method, detailed considerations were given on processes of forming the resolution as a result of arranging observation points at vibration transmitting and receiving points. In the discussion, numerical experiments were carried out, in which the scattering stacking process is applied in a model having one scatterer existing in homogeneous media. The experiments investigated an imaging formation process of the scatterer when arrangement of the vibration transmitting and receiving points were changed from a coarse condition to a dense condition while the number of transmitting and receiving points is being increased. Resolution is created if waveforms having finite frequencies are used as input, and the imaging is performed by utilizing the limited number of vibration receiving and transmitting points. If the concept of ...

International Nuclear Information System (INIS)

Magnetic properties of the Al1-xGaxFeO3 family of oxides crystallizing in a non-centrosymmetric space group have been investigated in detail along with structural aspects by employing X-ray and neutron diffraction, Moessbauer spectroscopy and other techniques. The study has revealed the occurrence of several interesting features related to unit cell parameters, site disorder and ionic size. Using first-principles density functional theory based calculations, we have attempted to understand how magnetic ordering and related properties in these oxides depend sensitively on disorder at the cation site. The origin and tendency of cations to disorder and the associated properties are traced to the local structure and ionic sizes. -- Graphical abstract: We have studied both experimentally and theoretically the important role of disorder at the cation site on magnetic and related properties of the Al1-xGaxFeO3 ...

International Nuclear Information System (INIS)

Neutron powder diffraction and magnetometric studies of the HoRh_2_-_xPd_xSi_2 series of solid solutions (x=0, 0.5, 0.75, 1.0, 1.5, 1.8) are reported. The intermetallics investigated crystallize in the body-centred-tetragonal ThCr_2Si_2-type structure (space group I4/mmm). All the samples order antiferromagnetically at low temperatures. For low values of the dilution parameter x a simple collinear antiferromagnetic structure of the AFI type is stable. Below T_N the magnetic moments are parallel to the c-axis and then, below T_t, deflect forming an angle #psi# with the c-axis. Further replacement of Rh by Pd results in the development of a sine-wave-modulated magnetic structure with one two-component propagation vector and magnetic moments in the basal plane. For x=1.8 a sine-wave-modulated structure similar to that reported for HoPd_2Si_2 (i.e. with a two-component propagation vector and ...

Energy Technology Data Exchange (ETDEWEB)

We discuss recent results obtained for the heavy-fermion metals UPd{sub 2}Al{sub 3} and YbRh{sub 2}Si{sub 2}. UPd{sub 2}Al{sub 3} is the first among all superconductors for which tunneling and inelastic neutron-scattering data highlight a non-phononic, i.e., magnetic-exciton mediated, pair state. YbRh{sub 2}Si{sub 2} represents a model system exhibiting pronounced non-Fermi liquid effects above a weak antiferromagnetic phase transition at T{sub N}=70 mK. Upon approaching the quantum critical point (T{sub N}{yields}0), by low doping with Ge, one observes for T<0.3 K disparate behavior in the temperature dependences of both the electrical resistivity and the electronic specific heat as well as a Curie-Weiss law in the uniform magnetic susceptibility, implying uncompensated large 4f moments. These observations indicate a break up of the composite quasiparticles into their local f-spin and itinerant conduction-electron ...

Energy Technology Data Exchange (ETDEWEB)

Solid-state nuclear magnetic resonance (NMR) has been used to explore the nanometer-scale structure of Nafion, the widely used fuel cell membrane, and its composites. We have shown that solid-state NMR can characterize chemical structure and composition, domain size and morphology, internuclear distances, molecular dynamics, etc. The newly-developed water channel model of Nafion has been confirmed, and important characteristic length-scales established. Nafion-based organic and inorganic composites with special properties have also been characterized and their structures elucidated. The morphology of Nafion varies with hydration level, and is reflected in the changes in surface-to-volume (S/V) ratio of the polymer obtained by small-angle X-ray scattering (SAXS). The S/V ratios of different Nafion models have been evaluated numerically. It has been found that only the water channel model gives the measured S/V ratios in the normal hydration ...

Energy Technology Data Exchange (ETDEWEB)

The consistency of different instruments and methods for measuring two-dimensional (2D) power spectral density (PSD) distributions are investigated. The instruments are an interferometric microscope, an atomic force microscope (AFM) and the X-ray Reflectivity and Scattering experimental facility, all available at Lawrence Berkeley National Laboratory. The measurements were performed with a gold-coated mirror with a highly polished stainless steel substrate. It was shown that these three techniques provide essentially consistent results. For the stainless steel mirror, an envelope over all measured PSD distributions can be described with an inverse power-law PSD function. It is also shown that the measurements can be corrected for the specific spatial frequency dependent systematic errors of the instruments. The AFM and the X-ray scattering measurements were used to determine the modulation transfer function of the ...

International Nuclear Information System (INIS)

The isostructural uranium monopnictides and monochalcogenides have become prototype systems in actinide research with respect to their unusual magnetic properties. We have investigated the origins in the electronic structure of the variation in magnetic behavior as the degree of 5f-electron localization changes from localized to itinerant on going up the pnictogen or chalcogen column, thus decreasing the U-U separation. We have applied a synthesis of: (1) A phenomenological theory of orbitally driven magnetic ordering which includes both the hybridization-induced and the RKKY exchange interactions on an equal footing, and (2) Ab initio electronic structure calculations, based on the linear-muffin-tin-orbital method, allowing a first-principles evaluation of the parameters entering the model Hamiltonian. We have investigated systematically characteristic trends and changes of the ...

International Nuclear Information System (INIS)

... parameters magnetic fields magnetic properties magnetization monocrystals

International Nuclear Information System (INIS)

Single-crystalline CeRh_2Si_2 and CePd_2Si_2 were grown by the Czochralsky pulling method and the temperature dependence of magnetic susceptibility was investigated. The crystalline electric field (CEF) states in each compound were determined by considering the tetragonal CEF Hamiltonian with mean-field approximation. Interactions between Ce"3"+ ion and the surrounding ligands in CeRh_2Si_2 turned out to be strong and highly anisotropic in comparison to CePd_2Si_2. (orig.)

Science.gov (United States)

Elastic electromagnetic form factors of nucleons are investigated for both the time-like and the space-like momenta by using the unsubtracted dispersion relation with QCD constraints. It is shown that the calculated form factors reproduce the experimental data reasonably well; they agree with recent experimental data for the neutron magnetic form factors for the space-like data obtained by the CLAS Collaboration and are compatible with the ratio of the electric and magnetic form factors for the time-like momentum obtained by the BABAR Collaboration.

Energy Technology Data Exchange (ETDEWEB)

The magnitude of electric and magnetic fields around a high voltage three-phase transmission line was studied. A three-phase transmission circuit with parallel conductors produces rotating elliptic electric and magnetic fields. This study investigated the optimum arrangement of the phase conductors to minimize the maximum value of the magnetic flux density and to minimize the intensity of the resultant electric field. Two different types of high voltage double circuit transmission lines of 400 kV were considered. The optimum arrangement of the phase conductors was determined. It was concluded that the optimum arrangement can be easily applied to already constructed high voltage transmission lines by properly interchanging the phase conductors at the substations. 10 refs., 1 tab., 4 figs.

International Nuclear Information System (INIS)

Normal state nuclear magnetic resonance studies of the La_3In, La_3Tl compounds have been made in order to investigate the origin of the large temperature-dependent magnetic susceptibility. It is possible to analyse the different contributions to the susceptibility using Knight-shift and relaxation time T_1 measurements of In"1"1"5 and Tl"2"0"5 nuclei. The exchange enhancement of the spin-susceptibility chisub(pd) is of the same order as that found in A-15 compounds and the strong temperature-dependence of chi(T) is attributed to the presence of a peak in the electronic density of states near the Fermi level. The variation of the Knight-shift in the ternary alloys La_3Xsub(1-y)Xsub(y)sup(') is analogous to that observed in the corresponding La_3X phases, on the other hand the Knight-shift in the carbides La_3XC is temperature independent. (author).

British Library Electronic Table of Contents (United Kingdom)

Magnetic properties of Fe-Co-Mo-Cu-B alloy system with Co up to 26at.% were investigated. After proper thermal treatment, the nanocrystalline grain remains tiny, the density hardly increases, but the room-temperature saturation attains 1.5T mainly due to a high enough Curie temperature. The generally observed slant hysteresis loops point to ribbon surfaces, which stress the ribbon interior and induce a specific magnetoelastic contribution to hard-ribbon-axis magnetic anisotropy even after vacuum annealing. The effect does not come from cobalt but rather from the lack of silicon. Partial removal of the surfaces resulted in a decrease of the loop tilt.

CERN Document Server

We calculate the quarkonium dissociation rate in the P and CP-odd domains (bubbles) that were possibly created in heavy-ion collisions. In the presence of the magnetic field produced by the valence quarks of colliding ions, parity-odd domains generate electric field. Quarkonium dissociation is the result of quantum tunneling of quark or antiquark through the potential barrier in this electric field. The strength of the electric field in the quarkonium comoving frame depends on the quarkonium velocity with respect to the background magnetic field. We investigate momentum, electric field strength and azimuthal dependence of the dissociation rate. Azimuthal distribution of quarkonia surviving in the electromagnetic field is strongly anisotropic; the form of anisotropy depends on the relation between the electric and magnetic fields and quarkonium momentum. These features can be used to explore the ...

Energy Technology Data Exchange (ETDEWEB)

Magnetite nanoparticles with high self-heating capacity and low toxicity characteristics are a promising candidate for cancer hyperthermia treatment. In order to achieve minimum dosage to a patient, magnetic nanoparticles with high heating capacity are needed. In addition, the influence of physiological factors on the heat capacity of a material should be investigated in order to determine the feasibility. In this study, magnetite nanoparticles coated with lauric acid were prepared by co-precipitation of Fe{sup 3+}:Fe{sup 2+} in a ratio of 2:1, 5:3, 3:2, and 4:3, and the pH was controlled using NaOH. Structural and magnetization characterization by means of X-ray diffractometry (XRD) and a superconducting quantum interference device (SQUID) revealed that the main species was Fe{sub 3}O{sub 4} and further showed that most of the nanoparticles exhibited superparamagnetic properties. All of the magnetic ...

UK PubMed Central (United Kingdom)

Scatter correction is crucial to the quality of reconstructed images in x-ray cone-beam computed tomography (CBCT). Most of existing scatter correction methods assume smooth scatter distributions. The...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The scattering of a charged scalar field on Coulomb potential on de Sitter space-time is studied using the solution of the free Klein-Gordon equation. We find that the scattering amplitude is independent of the choice of the picture and in addition the total energy is conserved in the scattering process.

Science.gov (United States)

We analyze new data from Thomas Jefferson National Accelerator Facility (JLab) for inclusive electron scattering on various targets. Computed and measured total inclusive cross sections in the range 0.3 < or approx. x < or approx. 0.95 show reasonable agreement on a logarithmic scale for all targets. However, closer inspection of the quasielastic components reveals serious discrepancies. European Muon Collaboration (EMC) ratios with conceivably smaller systematic errors fare the same. As a consequence, the new data do not enable the extraction of the magnetic form factor G{sub M}{sup n} and the structure function F{sub 2}{sup n} of the neutron, although the application of exactly the same analysis to older data had been successful. We incorporate in the above analysis older CLAS Collaboration data on F{sub 2}{sup 2H}. Removal of some scattered points from those makes it appear possible to obtain the desired neutron ...

Energy Technology Data Exchange (ETDEWEB)

The Tevatron accelerator at Fermilab incorporates long two-phase helium passages. During magnet design, the generalized flow map of Baker was used to predict homogeneous flow. Longer than expected magnet time constants led to this investigation. The importance of predicting the flow regime has been amplified with the advent of non-horizontal accelerator designs. A test setup was constructed at Fermilab to investigate two-phase helium flow regimes for conditions practical in accelerator designs. The setup consisted of a standard Tevatron satellite refrigerator, subcooling dewar, heater, 35 m long transfer line, and a specialized end box. A knife blade on the midplane of the transfer line diverted the flow from the upper and lower halves of the pipe to separate vessels in the end box. The amount of liquid above and below the plane was measured at various total mass flow rates and liquid percentages. The ...

Energy Technology Data Exchange (ETDEWEB)

Although studied for many years the nature of the light scalar mesons remains controversial. Here we shall present a method, applicable for s-wave states located close to a threshold, that allows one to quantify the molecular part of a given state. When applied to the f{sub 0}(980) a dominance of the molecular component is found. In the second part, we show that requirements of field-theoretic consistency and chiral symmetry, when applied to the scattering of light pseudo-scalars, naturally lead to the appearance of dynamical poles in the scalar sector. A program is proposed on how to further investigate experimentally the mixing between these dynamical states and possible genuine quark states. (orig.)

International Nuclear Information System (INIS)

Phase transformations in TiD_#approx#_0_._7_5 subjected to high-pressure treatment were investigated by simultaneous real-time measurements of neutron diffraction and small-angle neutron scattering. The neutron spectra were taken on heating the samples in temperature ranges 100 to 300 K and 300 to 870 K. A sequence of structural transitions was observed, which involves 7 different phases and intermediate states with hcp, fcc, fco or bcc metal sublattices and hydrogen atoms. 30 refs., 9 figs., 1 tab.

Energy Technology Data Exchange (ETDEWEB)

We investigate the interplay of quark and meson degrees of freedom in a physical state representing a near-threshold resonance for the case of a single continuum channel. We demonstrate that such a near-threshold resonance may possess quite peculiar properties if both quark and meson dynamics generate weakly coupled near-threshold poles in the S -matrix. In particular, the scattering t -matrix may possess zeros in this case. We also discuss possible implications for production reactions as well as studies within lattice QCD. (orig.)

Science.gov (United States)

Spectral and energy luminescence characteristics of R6G dye solutions in ethanol with addition of Ag nanoparticle suspensions in different aggregate states are experimentally investigated. It is demonstrated that incorporation of non-aggregated and aggregated nanoparticles causes the superluminescence thresholds in R6G solutions to decrease. It is established that the optical properties of the laser beam propagation channel are transformed when low-power (20 mW) cw laser radiation passes through the suspension of nanoparticles. This is manifested through the occurrence of a region with enhanced nanoparticle density in the laser beam center, on which diffraction of laser radiation is observed.

International Nuclear Information System (INIS)

We investigate the chargino production process #gamma##gamma# #-># (W-tilde)"+(W-tilde)"- at high energy #gamma##gamma# colliders in the framework of the minimal supersymmetric standard model (MSSM). Here the high energy #gamma# beams are obtained by the backward Compton scattering of the laser flush by the electron in the basic linear TeV ee colliders. We consider the polarization of the laser photons as well as the electron beams. Appropriate beam polarization could be effective to enhance the cross section to for us extract the signal from the dominant background #gamma##gamma# #-># W"+W"-. (author).

Energy Technology Data Exchange (ETDEWEB)

Electromagnetic fields have been reported to cause a variety of biological effects. It has been hypothesized that many of these phenomena are mediated by a primary effect on the concentration of cytosolic free calcium ((Ca2+)i). We investigated the effects of exposure to electromagnetic fields on (Ca2+)i in HL-60 cells using the Ca2(+)-sensitive fluorescent indicator indo-1. Indo-1-loaded cell samples were exposed to a radiofrequency electromagnetic field, a static magnetic field, and a time-varying magnetic field, which were generated by a magnetic resonance imaging (MRI) unit. We found that a 23-min exposure to all three fields, in combination, induced a significant increase in (Ca2+)i of 31 +/- 8 (SE) nM (P less than 0.01, n = 13) from a basal level of 121 +/- 8 nM. Also, cells exposed to only the time-varying magnetic field had a mean (Ca2+)i that was 34 +/- 10 nM (P less than ...

International Nuclear Information System (INIS)

The magnetic structure of the cubic compound CeAl_2 is incommensurate and double-k. The moments on the two Ce sites describe two elliptical helices of opposed chiralities and lie in the (11-bar0) plane, with their Fourier components m"k close to the [111] direction. Recent symmetry considerations, including for the first time the inversion center of the crystal, have reduced the number of parameters of this structure and have underlined the existence of a phase difference between the projections m_x"k, m_y"k and m_z"k of m"k. Up to now, although many neutron investigations have been carried out on CeAl_2 single crystals, no set of magnetic intensities was available which was large and good enough to check whether this phase difference exists or not. We have measured such a set of data, taking great care of the instrumental resolution in order to avoid unwanted contributions to the intensities from other domains. As the ...

Energy Technology Data Exchange (ETDEWEB)

Liquid metal cooling for the first wall and blanket of a magnetic confinement fusion reactor has various advantages. However, it has the disadvantages of large magnetohydrodynamic pressure drops and heat transfer deterioration under a strong magnetic field. Thus, the present authors have proposed cooling with a helium-lithium annular mist flow as well as the cooling with a liquid metal boiling flow, and as fundamental studies, investigated the effect of a magnetic field on the flow characteristics and heat transfer of liquid metal two-phase systems since the 1970s. In the present paper we summarize the important findings obtained from our experimental studies for (i) an air-mercury stratified flow in a horizontal rectangular channel, (ii) a helium-lithium annular mist flow in a horizontal rectangular channel, (iii) the mercury pool boiling on a horizontal surface, and (iv) air-mercury upward flows in a ...

International Nuclear Information System (INIS)

The effect of the #+-# 0.75 T external magnetic field on the K_#alpha#_1, K_#alpha#_2, K_#beta#_'_1 and K_#beta#_'_2 x-ray production cross sections and radiative vacancy transfer probabilities from K-shell to L2 and L3 subshells and M-shell for ferromagnetic Nd, Gd and Dy and paramagnetic Eu and Ho have been investigated, using the 59.5 keV incident photons. K-shell fluorescence yields and K x-ray intensity ratios for these elements have been determined in the external magnetic field also. The K x-rays from different targets were detected using a high-resolution Si(Li) semiconductor detector. For B = 0, the present experimental results were compared with the experimental and theoretical data in the literature. The results show that K-shell fluorescence parameters such as photoionization cross section, fluorescence yield, radiation rates, vacancy transfer probabilities and spectral linewidth can change owing to the applied ...

CERN Document Server

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 ...

International Nuclear Information System (INIS)

Bobbin-coil-type eddy current probes, which are conventionally used for nondestructive inspection of steam generator tubes in pressurized-water-type nuclear power plants, have poor detectability for circumferential flaws. Hence a new type of eddy current probe was proposed to detect effectively the magnetic flux component disturbed by a flaw and thus to eliminate the flaw direction dependency on the flaw detectability. In the course of development of the proposed method, structures of the probe were investigated based on the measurement of magnetic fields induced by exciting flat coils with several shapes. The new type of probe proposed here consists of differential pick-up coils detecting magnetic flux and exciting coils having a parallelogrammic shape, and its structure was fabricated experimentally in order to detect flaws independently of their directions. Nondestructive flaw detection tests was ...

International Nuclear Information System (INIS)

Inelastic scattering of #alpha#-particles in 22-24 MeV energy range on "1"8o o, "1"9f, "2"0Ne, "2"2Ne nuclei is investigated. Measurements of excitation functions were conducted for the beam of Leningrad University cyclo otron at several angles in 15-165 deg range of laboratory system with 2.5 deg spacing. The error of determining absolute cross sections equals +-20% for "2"2Ne and +-12% for other nuclei. Angular distributions have the differaction character, are similar in form for all nuclei, the values of differential cross- -sections don't exceed the rutherford values. The dependence of integral cross-sections on the energy of level excitation is similar to the exponential d dependence of cross-sections of production of the given element isotopes on the gergy difference of masses of final nuclear products in the reactions of deeply inelastic transfers with heavy ions. The observed isotopic effect in the value of cross-sections of elastic ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes the calculation method of 3-D underground structures in TDME method which measures only field components. Recently, FDTD method was developed as calculation method in time domain difference calculus, and the forward analysis accuracy of 3-D fields was rapidly improved. The survey results using a large-scale loop (600m{times}360m) were numerically analyzed by FDTD method. 16 measuring lines were prepared in both X and Y directions, and measuring points were prepared on intersection points of the measuring lines. Since signal current is staircase one, step and impulse responses of the ground were determined by calculating magnetic field and its time differentiation. The rectangular body (120m{times}120m{times}100m) of 0.2S/m in conductivity (5 ohm m in resistivity) was installed 160m under the ground as 3-D resistivity anomaly. The ground of 0.01S/m (100 ohm m) was assumed. Time variation in horizontal magnetic field vector ...

Science.gov (United States)

... Examples include magnetic forming tools, magnetic shielding, magnetohydrodynamic propulsion systems, and various magnetic containment ...

Energy Technology Data Exchange (ETDEWEB)

An investigation was made of the accumulation of laser damage to transparent polymers irradiated with nanosecond pulses from neodymium and ruby lasers. The damage was investigated by the method of scattering and luminescence in the visible and near ultraviolet parts of the spectrum. It was established that there were two stages in laser damage by repeated irradiation with pulses of intensity below the single-shot damage threshold. An absorbing defect evolved during the first stage in such a way as to create a thermal instability in the surrounding matrix. During the second stage this thermal instability caused spatial growth of laser damage because of propagation of an ionization-inducing absorption wave with a front traveling at the rate governed by the electron component of the thermal conductivity.

International Nuclear Information System (INIS)

In globulitic gray iron (3.6 wt.% C, 2.4 wt.% Si and 0.45 wt.% Mn) the decomposition of austenite into bainite is investigated in real time using a new method based on neutron scattering. During the phase transformation transmission spectra of thermal neutrons are continuously recorded containing specific Bragg edges. Thus, the transformation is followed in-situ time resolved by evaluating the relative (micro)structural fractions of the transforming phases from the heights of the corresponding Bragg edges. The progression of the transformation is described and the results are discussed. The observed late time deviations from the Avrami law are explained by residual stresses of the second kind (homogeneous microstresses), which occur during the transformation because of the different specific volumes of the phases. ((orig.)).

International Nuclear Information System (INIS)

The most important results of theoretical and experimental studies of plasmas, which have been achieved at the IPJ in Swierk and IPPLM in Warsaw recently, are presented. Studies of physical phenomena in PF discharges, development of diagnostic techniques and research on new plasma technologies, as performed at IPJ, have been summarized. Studies of dense magnetized plasmas, investigation of physics and applications of laser-produced plasmas; and research on the development of advanced diagnostic techniques for the EUROATOM fusion program, as performed at IPPLM, are also described.

Energy Technology Data Exchange (ETDEWEB)

Lifetimes have been measured for a dipole band in {sup 139}Sm using DSAM. The deduced B(M1) and B(E2) values as well as B(M1)/B(E2) ratios are compared with calculations in the framework of the TAC (Tilted Axis Cranking) and SPAC (Shears mechanism with Principal Axis Cranking) models. The dipole band in {sup 139}Sm can be considered as a magnetic rotational band with a prolate or triaxial nuclear deformation. (orig.)

CERN Document Server

The hyperfine interactions at the uranium site in the antiferromagnetic USb2 compound were calculated within the density functional theory (DFT) employing augmented plane wave plus local orbital (APW+lo) method. We investigated the dependence of the nuclear quadruple interaction to the magnetic structure in USb2 compound. The result shows that the 5f-electrons have the tendency to be hybridized with the conduction electrons.

Energy Technology Data Exchange (ETDEWEB)

Electromagnetic effects excited by intense relativistic electron beams in plasmas are investigated using a two-dimensional particle code. The simulations with dense beams show large magnetic fields excited by the Weibel instability as well as sizeable electromagnetic radiation over a significant range of frequencies. The possible relevance of beam plasma instabilities to the laser acceleration of particles is briefly discussed. 6 refs., 4 figs.

UK PubMed Central (United Kingdom)

The aim of the study was to investigate the possible acute effects of exposure to electric and magnetic fields. Twenty six experienced linesmen, aged 25 to 52, were studied during two working days while...Full Text Available

International Nuclear Information System (INIS)

A preliminary investigation was completed on the characterization and decontamination of coral samples from Johnston Island. These samples were found to contain individual particles (2 to 0.25 mm) of contaminated coral as well as a piece of contaminated magnetic metal. They ranged in activity from about 70 to 811 nCi Am-241. The decontamination methods investigated were froth flotation, ferrite treatment, attrition scrubbing, ultrasonic treatment and dry sieving. Dry sieving, the more effective technique, separated about 42 wt % of the coral into a decontaminated fraction. This fraction (>4 mm) contained about 0.5% of the total activity. 7 refs., 3 tabs.

International Nuclear Information System (INIS)

Structure and magnetic properties of UNi_1_0_-_xFe_xSi_2 intermetallics and "2"9Si nuclear magnetic resonance (NMR) in UNi_1_0Si_2 are investigated in a wide temperature range. Solid solutions in the exactly single-phase tetragonal form, ThMn_1_2 type, exist for x<2. The Ni and Fe atoms occupy the 8(f), 8(i) and 8(j) positions statistically, whereas the U atoms occupy the 2(a) and the Si atoms the 8(j) sites. The lattice parameters roughly follow Vegard's law. The magnetic susceptibility does not exhibit Curie-Weiss behaviour and, at about 630 K, an anomaly in the temperature dependence is observed. At low temperature, other anomalies are observed at 32 K and 45 K, for x=0.5 and 1.0 respectively. These low temperature anomalies are probably connected with magnetic ordering of a ferromagnetic character, whereas that at 630 K might result from the superparamagnetic state of Ni. Two ...

International Nuclear Information System (INIS)

The cold-worked Zr-2.5%Nb alloy is used as material for the pressure tubes in CANDU nuclear reactors. During the service life in reactor, diffusion of hydrogen and/or deuterium in the pressure tubes wall occur. Below a certain temperature, a stable hydride of zirconium is formed, as a brittle phase which can lead to catastrophic failures. For this reason, it is very important to be able to investigate the hydrogen effect on the micro structural properties of zirconium alloys. In the present paper a non-destructive testing technique is used, known as ultrasonic spectral analysis. When an ultrasonic signal traverses a medium, the frequency components associated with the input signal are altered. By frequency analysing the reflected signals, it is possible to study and compare the material properties. The two major parameters measured in ultrasonic spectroscopy are the attenuation and the velocity of the waves. Attenuation is determined by the energy losses in ...

International Nuclear Information System (INIS)

Complete text of publication follows. The stability regime of the incommensurate phase of quartz is influenced by uniaxial stress. Hence, the phase transition can be induced under isothermal conditions by the application of external mechanical forces. Using real-time neutron scattering the time evolution of structural changes is investigated id detail during stress variations. The time dependent behaviour of the satellite reflection is compared with that one of the fundamental Bragg reflection which - via primary extinction - gives information about the perfection of the crystal. On increasing stress the perfection of the lattice is destroyed immediately while the modulated structure is built up with a delay of about 1 s. Decreasing the stress leads to a reverse behaviour. Moreover, there is evidence that under periodical load residual non-relaxed strain fields survive leading to a different temperature dependence as compared to static ...

International Nuclear Information System (INIS)

We have recently developed a high resolution quasielastic neutron scattering spectrometer LAM-80ET by applying mica crystals as analyzers and achieved a resolution of #DELTA##epsilon# = 1.3 #mu#eV using the 002 reflection. Single chain dynamics of polyethylene has been investigated below and above the melting temperature T_m (=135degC) to show the feasibility of the mica 002 reflection as the analyzer. It was found that elastic scattering intensity from polyethylene decreases very steeply around the T_m. Quasielastic broadening in the spectrum at Q = 0.082 A"-"1 is observed only above 210degC, which is 75degC higher than the T_m. From the analysis of the spectra by a curve-fitting method, the width of the quasielastic component was evaluated to be 1.8 #mu#eV at 250degC and the activation energy of the width to be 34 kJ/mol. (author).

Energy Technology Data Exchange (ETDEWEB)

Seiberg duality in supersymmetric gauge theories is the claim that two different theories describe the same physics in the infrared limit. However, one cannot easily work out physical quantities in strongly coupled theories and hence it has been difficult to compare the physics of the electric and magnetic theories. In order to gain more insight into the equivalence of two theories, we study the ''e{sup +}e{sup -}'' cross sections into ''hadrons'' for both theories in the superconformal window. We describe a technique which allows us to compute the cross sections exactly in the infrared limit. They are indeed equal in the low-energy limit and the equality is guaranteed because of the anomaly matching condition. The ultraviolet behavior of the total ''e{sup +}e{sup -}'' cross section is different for the two theories. We comment on proposed nonsupersymmetric ...

Energy Technology Data Exchange (ETDEWEB)

Small angle neutron scattering (SANS) has been a very powerful tool to study nanoscale (1-100 nm) bulk structures in various materials such as polymer, self assembled materials, nano-porous materials, nano-magnetic materials, metal and ceramics. Understanding the importance of the SANS instrument, the 8m SANS instrument was installed at the CN beam port of HANARO in 2001. However, without having a cold neutron source, the beam intensity is fairly low and the Q-range is rather limited due to short instrument length. In July 1, 2003, therefore, the HANARO cold neutron research facility project was launched and a state of the art 40m SANS instrument was selected as top-priority instrument. The development of the 40m SANS instrument was completed as a joint project between Korea Advanced Institute of Science and Technology and the HANARO in 2010. Here, we report the specification of a state of art 40m SANS instrument at HANARO

International Nuclear Information System (INIS)

Beams may be viewed as directed and focussed flow of energy and information, carried by particles and electromagnetic radiation fields (ie, photons). Often, they interact with each other (eg, in high energy colliders) or with other forms of matter (eg, in fixed targets, sychrotron radiation, neutron scattering, laser chemistry/physics, medical therapy, etc.). The whole art and science of beams revolve around the fundamental quest for, and ultimate implementation of, mechanisms of production, storage, control and observation of beams -- always directed towards studies of the basic structures and processes of the natural world and various practical applications. Tremendous progress has been made in all aspects of beam physics and technology in the last decades -- nonlinear dynamics, superconducting magnets and rf cavities, beam instrumentation and control, novel concepts and collider praradigms, to name a few. We illustrate this progress with a ...

Energy Technology Data Exchange (ETDEWEB)

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)

Energy Technology Data Exchange (ETDEWEB)

Reflectometric methods like polarised neutron reflectometry (PNR) and synchrotron Moessbauer reflectometry (SMR) are capable of investigating the plane-perpendicular and lateral magnetic structure of multilayers (MLs). Previously, a variety of domain formation and transformation phenomena was found and systematically studied in a Fe/Cr ML of strong antiferromagnetic coupling by PNR and SMR. Growth of the primary domains on passing the bulk-spin-flop transition was established. The domains were found to revert to their native state only in a field considerably higher than the apparent saturation field, a phenomenon referred to as the supersaturation domain memory effect (SDME). We present a comparative PNR study of two antiferromagnetically coupled Fe/Cr MLs with different magnetisation curves. We show that the distribution of the layer-layer coupling rather than the magnetic structure of the Cr spacer layer is responsible ...

Energy Technology Data Exchange (ETDEWEB)

We have investigated via SQUID magnetometry and polarised neutron reflectivity the exchange-bias effect in CoO/Co sputtered multilayers. In particular, we studied the magnetisation reversal and the time relaxation of the exchange-bias field close to the coercive field H{sub c1}. Neutron intensities of all four cross sections (I++, I+-, I-+, I-) were recorded at the position of the first multilayer Bragg peak while scanning the magnetic field. From such scans we infer that the magnetisation reversal for the ascending as well as for the descending branch of the magnetic hysteresis occurs not by in-plane rotation but through domain-wall movements. The exchange-bias field, H{sub EB}, is strongly affected by thermal fluctuations. H{sub EB} decreases, following an exponential decay function with a half-life time of about 580 s at T=240 K. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The magnetic susceptibility and electrical resistivity in cerium and neodymium titanate bronzes in Ln/sub 2/3+x/TiO/sub 3+y/ of the perovskite structure were investigated in the temperature range 77-450/sup 0/K. The deviation of the 1/x = f(T) dependence from the Curie-Weiss law, found for a majority of the compositions, was interpreted from the crystal-field effect based on the state of the Ce/sup 3 +/ and Nd/sup 3 +/ cations. For a number of the phases, a transition from metallic conductivity at high temperatures to semiconducting conductivity was detected at temperatures below 200-250/sup 0/K, which agrees well with the conclusion about the temperature dependence of x, related to the subsystem of Ti/sup 3 +/ cations.

Energy Technology Data Exchange (ETDEWEB)

Single-crystalline CeRh{sub 2}Si{sub 2} and CePd{sub 2}Si{sub 2} were grown by the Czochralsky pulling method and the temperature dependence of magnetic susceptibility was investigated. The crystalline electric field (CEF) states in each compound were determined by considering the tetragonal CEF Hamiltonian with mean-field approximation. Interactions between Ce{sup 3+} ion and the surrounding ligands in CeRh{sub 2}Si{sub 2} turned out to be strong and highly anisotropic in comparison to CePd{sub 2}Si{sub 2}. (orig.) 10 refs.

Energy Technology Data Exchange (ETDEWEB)

The thermal stability and deformability of Mn-Al-C alloys containing 0.6 pct C are investigated experimentally as a function of excess phase content. It is shown that an increase in Mn content from 68.9 to 73.5 pct leads to increased stability of the high-temperature epsilon phase. The enrichment of the system Mn-Al-Cu in Mn and Al above the optimum composition leads to the formation of nonmagnetic excess phases, eta and beta, which reduce the magnetization of the alloy. In addition, a decrease in thermal stability is observed in the alloy with 73.5 pct Mn due to the decomposition of the ferromagnetic phase. 7 references.

British Library Electronic Table of Contents (United Kingdom)

The present investigation is concerned with the effect of Hall currents on boundary layer flow, and heat and mass transfer of an electrically conducting fluid over an unsteady stretching sheet in the presence of a strong magnetic field. The electron-atom collision frequency is assumed to be relatively high, so that the Hall effect is assumed to exist, while the induced magnetic field is neglected. The governing time-dependent boundary layer equations for momentum, thermal energy, and concentration are reduced using a similarity transformation to a set of coupled ordinary differential equations. The similarity ordinary differential equations are then solved numerically by the successive linearization method together with the Chebyshev pseudo-spectral collocation method. Effects of the Prand...

Energy Technology Data Exchange (ETDEWEB)

The rare-earth based nickelates RNiO{sub 3} (R = Pr, Nd, Sm, Eu, and Pr{sub 1-x}La{sub x}, 0{<=}x{<=}0.7) were studied by inelastic neutron scattering. Energy splittings due to the crystalline-electric-field (CEF) interaction at the R{sup 3+} site within the electronic ground-state J multiplet (for R = Pr, Nd, and Pr{sub 1-x}La{sub x}) as well as within the two lowest-lying J multiplets (for R = Sm and Eu) were directly observed, and the corresponding CEF energy-level schemes were reconstructed. The latter were rationalized in terms of CEF parameters, which vary smoothly over the rare-earth series and give magnetic properties associated with the R sublattice in agreement with results from neutron powder diffraction experiments. Across the metal-insulator transition, a continuous change in the electronic part of the CEF parameters is observed. However, an attempt to quantify a charge transfer from the observed variation of the CEF ...

International Nuclear Information System (INIS)

The rare-earth based nickelates RNiO_3 (R=Pr, Nd, Sm, Eu, and Pr_1_-_xLa_x, 0#<=#x#<=#0.7) were studied by inelastic neutron scattering. Energy splittings due to the crystalline-electric-field (CEF) interaction at the R"3"+ site within the electronic ground-state J multiplet (for R=Pr, Nd, and Pr_1_-_xLa_x) as well as within the two lowest-lying J multiplets (for R=Sm and Eu) were directly observed, and the corresponding CEF energy-level schemes were reconstructed. The latter were rationalized in terms of CEF parameters, which vary smoothly over the rare-earth series and give magnetic properties associated with the R sublattice in agreement with results from neutron powder diffraction experiments. Across the metal-insulator transition, a continuous change in the electronic part of the CEF parameters is observed. However, an attempt to quantify a charge transfer from the observed variation of the CEF parameters in an effective point charge ...

CERN Document Server

Specification of the steel sheet for the 300 GeV magnet system

Science.gov (United States)

Necessary theoretical foundation is given for the treatment of magnetic stresses applied to

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

Discussion of an electrohydraulic and magnetic forming process

International Nuclear Information System (INIS)

Thomson scattering is the process in which a low-energy photon scatters from a free electron. When a laser pulse propagates through a plasma, the spectrum of the scattered light due to the Thomson scattering is proportional to the power spectrum of the electron density fluctuations, i.e., dynamic form factor, from which various plasma parameters can be inferred, such as electron temperature and plasma flow velocity. After years of development. Thomson scattering has now become a powerful diagnostic tool of plasma physics. (authors)

International Nuclear Information System (INIS)

Superparamagnetic MFe23+O4 (M=Mn2+, Fe2+ and Co2+) inverse spinel ferrite (ISF) nanoparticles with narrow size distribution having average diameters of 6-8 nm were synthesized by a diol reduction of organic metals and the surface was modified to be hydrophilic by coating with succimer. Magnetic resonance imaging (MRI) contrast enhancement by dipolar coupling defined interactions between the synthesized ISFs and protons in the bulk water was investigated with initial susceptibility, magnetization and anisotropy of the succimer-coated ISFs. The relaxivity ratios, r2/r1, for MnFe2O4, Fe3O4 and CoFe2O4 were measured to be 12.2, 23.1 and 62.3, respectively, which demonstrate the potential usefulness of these magnetic nanoparticles as T2 contrast agents for MRI.

International Nuclear Information System (INIS)

The possibility of Pt-Cr surface alloys formation on Pt(0 0 1) was investigated and their magnetism was calculated by the full-potential linearized augmented plane wave (FLAPW) method with eight different atomic configurations. The most stable structure was calculated to be the Pt-segregated L1_2 ferromagnetic surface alloy. A_3B types (L1_2 or D0_2_2) were more stable compared to AB types (L1_0). It implies that the A_3B type surface alloys may be formed when depositing a monolayer of Cr on Pt(0 0 1). It was found from the total energy calculations that there exists a strong tendency of the Pt segregation. The segregation further stabilizes the surface alloy significantly. The work function of the most stable surface alloy was calculated to be 6.02 eV and the magnetic moment of the surface Cr was much enhanced to 3.3 #mu# _B. It is a quite interesting finding that the coupling between Cr and Pt atoms on the surface plane ...

International Nuclear Information System (INIS)

The authors have measured the magnetization of single-phase 90-K superconductors, GdBa_2Cu_3O/sub 6+#delta#/, EuBa_2Cu_3O/sub 6+#delta#/, and SmBa_2Cu_3O/sub 6+#delta#/ with a SQUID magnetometer. They have shown that, in the superconducting state, each magnetization-field curve exhibits a maximum at #approx# 100 G, followed by a linear increase of the magnetization with a slope only approximately one-fifth of the slope for a field smaller than 50 G. They have also investigated the effect of #gamma#-irradiation on YBa_2Cu_3O/sub 6+#delta#/, SmBa_2Cu_3O/sub 6+#delta#/, and have found that the radiation damage results in the appearance of a tail in the superconducting transition. They have also shown that the normal resistance decreases with increasing radiation exposure up to a dose of 10 Mrad.

British Library Electronic Table of Contents (United Kingdom)

The effect of Mo addition on the glass-forming ability (GFA), magnetic properties, mechanical properties and corrosion resistance of (Fe0.76Si0.096B0.084P0.06)100-xMox (x=0, 2, 4 and 6at.%) bulk glassy alloys (BGAs) with high Fe contents was investigated. The 2at.% Mo addition makes the alloy composition approach towards a eutectic point, which could result in an increase in the GFA. The BGA rod with diameters up to 3.5mm was produced by copper mold casting. These BGAs exhibit a rather high saturation magnetization of 0.98-1.51T and lower coercive force of 1.7-2.1A/m. A significant improvement in corrosion resistance was observed with microalloying Mo element in 1N H2SO4 solution. Furthermore, these Fe-based BGAs show super-high strength of ~3.3GPa and Young's modulus of 200GPa.

Energy Technology Data Exchange (ETDEWEB)

Recent analyses of the anisotropy of cosmic rays at 10{sup 18} eV (the AGASA and SUGAR data) show significant excesses from regions close to the galactic centre and Cygnus. Our aim is to check whether such anisotropies can be caused by single sources of charged particles. We investigate propagation of protons in two models of the galactic regular magnetic field (with the irregular component included) assuming that the particles are injected by a short-lived discrete source lying in the direction of the galactic centre. We show that apart from a prompt image of the source, the regular magnetic field may cause delayed images at quite large angular distances from the actual source direction. The image is strongly dependent on the time elapsed after ejection of particles and it is also very sensitive to their energy. For the most favourable conditions for particle acceleration by a young pulsar, the predicted fluxes are two to ...

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The temperature dependence of the spontaneous magnetization of epitaxial iron films with a thickness ranging from d=20 to 200nm has been measured. The films are grown on GaAs (100) substrates which are covered by a 150nm thick silver (100) buffer layer. For three-dimensional BCC iron it was observed already in 1929 that saturation of the spontaneous magnetization for T->0 is perfectly described by a T{sup 2} power law. On the other hand, for thin two-dimensional (2D) iron films a T{sup 3/2} law has been established in many recent experimental investigations. In our iron films grown on diamagnetic silver, this dimensionality change occurs at a thickness between d=100 and 200nm. Comparison of the here-observed T{sup 3/2} coefficients with those on iron films grown on paramagnetic tungsten (110) shows that the 2D interactions are {approx}20 times larger in the films on tungsten. Recent results on Fe films which are ...

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The effect of transverse magnetic field parameter (Hartmann number, Ha) Reynolds number (Re) and Prandtl number (Pr) on the mixed convection flow past a semi-infinite vertical porous plate in a non-Darcian porous medium with variable viscosity and porosity, viscous dissipation and fluid-solid thermal conductivity ratio in the presence of plate transpiration (lateral mass flux) is investigated theoretically and numerically using Keller`s implicit finite difference scheme. It is shown that the Harmann number acts as a retarding force and increases the momentum boundary layer thickness, analogous to the flow against a positive pressure gradient, simultaneously decreasing local skin friction (shear stress). The heat transfer rate is however enhanced by the magnetic field (for positive values of the Eckert number) since the fluid is heated and temperature gradients become reduced between the fluid and the plate, with important ...

International Nuclear Information System (INIS)

... excited states inelastic scattering mev range 10-100 mev range 100-1000

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We write a space-time Feynman Path Integral representation for scattered wave fields from a weakly/compact supported anisotropic non-homogeneity. (author)

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The diffusion of methane confined in nano-porous carbon aerogel with the average pore size 48 {angstrom} and porosity 60% was investigated as a function of pressure at T = 298 K using quasi-elastic neutron scattering (QENS). The diffusivity of methane shows a clear effect of confinement: it is about two orders of magnitude lower than in bulk at the same thermodynamic conditions and is close to the diffusivity of liquid methane at 100 K (i.e. {approx} 90 K below the liquid-gas critical temperature T{sub C} {approx} 191 K). The diffusion coefficient (D) of methane initially increases with pressure by a factor of {approx}2.5 from 3.47 {+-} 0.41 x 10{sup -10} m{sup 2} s{sup -1} at 0.482 MPa to D = 8.55 {+-} 0.33 x 10{sup -10} m{sup 2} s{sup -1} at 2.75 MPa and starts to decrease at higher pressures. An explanation of the observed non-monotonic behavior of the diffusivity in the confined fluid is based on the results of small-angle neutron ...

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Characteristics of pressure drop and heat transfer have been investigated for a lithium single-phase flow and a helium-lithium two-phase flow in a horizontal conducting circular channel in the presence of a uniform transverse magnetic field up to 1.4 T as related to the lithium cooling for magnetic-confinement fusion reactors. By the application of the magnetic field to the lithium single-phase flow, remarkable heat transfer enhancement has been observed at the top wall due to the suppression of the mixed convection occurring in the low Peclet number range, while appreciable heat transfer deterioration appeared in the high Peclet number range. It has been confirmed that the helium-lithium two-phase flow can reduce the high magnetohydrodynamic (MHD) pressure drop in a lithium single-phase flow, and it can provide much better heat transfer performance than that in a helium single-phase flow. In the ...

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The advent, in the near future, of compact X-ray sources like Thomson Back-Scattering (TBS) will allow the clinical application of advanced X-ray imaging techniques, such as phase contrast, with higher sensitivity and lower impact in terms of dose delivery. In this work, we theoretically investigated the possibility of using such sources for phase contrast imaging of micro-calcifications included in a breast tissue. In our study we analyzed the phase and amplitude distribution of the TBS source and we showed that this source can be used for phase contrast imaging since the source coherence at the sample position is sufficiently high for achieving good contrast and micrometer spatial resolution. Indeed the spatial coherence of a TBS source is closer to that of a synchrotron radiation source, and much better than that of a laboratory source. Moreover, we showed the advantages of phase imaging with respect to standard absorption imaging, in the ...

International Nuclear Information System (INIS)

The spin relaxation processes within the pyrochlore Ho_2Ru_2O_7 have been investigated by neutron scattering and bulk property techniques. A single-ion process, that is thermally activated, dominates the spin-spin relaxation spectrum above 2 K. Assuming Arrhenius behaviour, we found an activation energy #DELTA# = (329 #+-# 6) K and characteristic relaxation time #tau#_0 (5.2 #+-# 0.3) x 10"-"1"2 s in the paramagnetic state, akin to those found in the spin ice, Ho_2Ti_2O_7. Atlow temperature (T<95 K) the activation energy lowers and below 20 K the entropy and ac susceptibility are similar to that observed in other spin ice compounds within a 10 kOe field.

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The photocytotoxic effect of hypericin (Hyp) targeted by two different delivery techniques, namely, liposomes and anti-hepatocyte specific antigen (anti-HSA) was investigated. Optical absorption and steady-state fluorescence were used to analyze the conjugation of Hyp with anti-HSA model and to evaluate the encapsulation capacity and drug release in a liposome model. Particle size and thermal analysis of the prepared liposomes were performed using laser-light scattering and differential scanning calorimetry (DSC), respectively. Viability study of HepG2 cells exposed to Hyp in the two delivery systems, in the dark and following visible light irradiation, was performed in comparison to free Hyp. The intracellular uptake and localization of Hyp in HepG2 cells were analyzed by means of spectro...

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Here, a general approach for the preparation of reduced graphite oxide (rGO)-silver nanocomposite has been investigated. Graphite oxide (GO) sheets are used as the nanoscale substrates for the formation of rGO-silver composite. GO sheets and Ag ions can be reduced at the same time, under a mild condition using l-ascorbic acid (l-AA) as reducing agent. This simple approach should find practical applications in the production of rGO-silver nanocomposite. The SEM analysis indicates that the silver particles are dispersed on graphene sheets. Raman signals of rGO in the composite are increased by the attached silver nanoparticles, displaying surface-enhanced Raman scattering activity. The degree of enhancement can be adjusted by varying the quantity of silver nanoparticles in the composite. In ...

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The dd{yields}{sup 4}He{eta} reaction has been investigated near threshold using the ANKE facility at COSY-Juelich. Both total and differential cross-sections have been measured at two excess energies, Q=2.6 MeV and 7.7 MeV, with a subthreshold measurement being undertaken at Q=-2.6 MeV to study the physical background. While consistent with isotropy at the lower energy, the angular distribution reveals a pronounced anisotropy at the higher one, indicating the presence of higher partial waves. Options for the decomposition into partial amplitudes and their consequences for the determination of the s-wave {eta}{alpha} scattering length are discussed. (orig.)

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One third of the microstructure of glassy carbon (GC) consists of closed pores. Density measurements indicate that the total pore volume depends only on the heat treatment temperature and not on the heat treatment time, a characteristic of coarsening. The kinetics of coarsening of these pores on heat treatment has been investigated by analyzing the changes in specific surface area of the pores as determined by the small angle X-ray scattering (SAXS) technique. A part of the surface area change is due to thermal expansion induced microcracking. Both the superposition method after correcting the thermal expansion induced surface area change and the curve fitting method give an activation energy of 64 +/- 10 kcal/mole. This value is compared with the activation energies of various rate processes in graphite. A model of coarsening of the pores based on a vacancy migration mechanism is proposed.

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ABSTRACT New observations from the Hubble Ultra Deep Field suggest that the star formation rate at Formula Not Shown drops off faster than previously thought. Using a newly determined star formation rate for the normal mode of Population II/I (PopII/I) stars, including this new constraint, we compute the Thomson scattering optical depth and find a result that is marginally consistent with Wilkinson Microwave Anisotropy Probe 5 results. We also reconsider the role of Population III (PopIII) stars in light of cosmological and stellar evolution constraints. While this input may be needed for reionization, we show that it is essential in order to account for cosmic chemical evolution in the early universe. We investigate the consequences of PopIII stars on the local metallicity distribution fu...

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ABSTRACT With corn starch as raw material, dextrin was prepared by the combined application of common neutral and thermostable a-amylases in this study. The effects of reaction temperature, reaction time, addition of common neutral and thermostable a-amylases on dextrose equivalent (DE)-value of dextrin were investigated. The obtained dextrin with a DE value of 20.43 was evaluated for morphology, crystallography, particle size distribution and thermal property by scanning electron microscope, X-ray diffractometer, light scattering particle size analyzer and thermogravimetric analyzer. The results showed that the amorphous regions in the core part of corn starch were completely hydrolyzed and only the fractured crystalline surface remained. The particle size of the dextrin change significan...

CERN Document Server

Luminosity-driven channeling extraction has been observed for the first time in a 900 GeV study at the Fermilab Tevatron. This experiment, Fermilab E853, demonstrated that useful TeV level beams can be extracted from a superconducting accelerator during high luminosity collider operations without unduly affecting the background at the collider detectors. Multi-turn extraction was found to increase significantly the efficiency of the process. The beam extraction efficiency was about 25%. Studies of time dependent effects found that the turn-to-turn structure was governed mainly by accelerator beam dynamics. An investigation of a pre-scatterer using the accelerator flying wire system showed that a fiber could produce a significant extracted flux, consistent with expectations. Based on these results, it is feasible to construct a parasitic 5-10 MHz proton beam from the Tevatron collider.

International Nuclear Information System (INIS)

The gliding modes of a duplex Ti-6Al-4V titanium alloy were investigated through in situ (scanning electron microscopy) tensile tests. A method based on electron back-scattering diffraction (EBSD) measurements was used to identify activated slip systems. The approach applied to a large number of grains allowed a statistical analysis of the nature (basal, prismatic, pyramidal) and distribution of the slip systems according to the crystallographic texture. A discussion concerning the pertinence of Schmid's law to explain the occurrence and succession of slip events is then proposed. The domain in favor of each type of slip system is finally presented by using inverse pole figures mapped with Schmid's factor iso-curves.

International Nuclear Information System (INIS)

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 ...

International Nuclear Information System (INIS)

High-resolution proton nuclear magnetic resonance spectroscopy has been used to investigate the molecular mechanism of the Bohr effect of human normal adult hemoglobin in the presence of two allosteric effectors, i.e., chloride and inorganic phosphate ions. The individual hydrogen ion equilibria of 22-26 histidyl residues of hemoglobin have been measured in anion-free 0.1 M HEPES buffer and in the presence of 0.18 M chloride or 0.1 M inorganic phosphate ions in both deoxy and carbonmonoxy forms. The results indicate that the #beta#2-histidyl residues are strong binding sites for chloride and inorganic phosphate ions in hemoglobin. The affinity of the #beta#2-histidyl residues for these anions is larger in the deoxy than in the carbonmonoxy form. Nevertheless, the contribution of these histidyl residues to the anion Bohr effect is small due to their low pK value in deoxyhemoglobin in anion-free solvents. The interactions of chloride and ...