WorldWideScience
1

Major evolutionary transitions in ant agriculture  

UK PubMed Central (United Kingdom)

Agriculture is a specialized form of symbiosis that is known to have evolved in only four animal groups: humans, bark beetles, termites, and ants. Here, we reconstruct the major evolutionary transitions...Full Text Available

2008-04-08

3

Nucleonic versus nuclear spin-isospin polarization. A study of the /sup 48/Ca and /sup 88/Sr M1 form factors  

Energy Technology Data Exchange (ETDEWEB)

We compare standard nuclear polarization mechanisms, ..delta..-hole-polarization and meson-exchange-current effects in the q-dependent quenching of isovector spin transitions. Calculations are performed for the M1-transition form factors of the 1/sup +/ states in /sup 48/Ca (10.23 MeV) and /sup 88/Sr (3.48 MeV). We obtain a satisfactory description of both form factors if the repulsive part of the residual interaction in the ..delta..-hole channel is of similar strength to that in the nucleon-hole channel. Meson-exchange currents lead to an enhancement of M1 transitions by an amount which is small in general, but sensitive to the particular nuclear state involved. 44 references.

1984-06-04

4

On the mechanism of the nonmonotonic relaxation processes in the metallic melts  

International Nuclear Information System (INIS)

The numerical analysis of the experimental data on viscosity change by time in the period after fast heating and crystal-liquid phase transition for the copper nonequilibrium melts and the Fe_7_0Cr_1_0P_1_3C_7 glass-forming melt near their melting temperatures is accomplished through the method of correlation functions and the Rytov-Dimentberg criterion. The observed dependences have nonmonotonic oscillating character but they do not relate to auto-oscillations. The proposed theoretical model of the properties oscillations origination by relaxation in the nonequilibrium liquids explains them as manifestation of noise-induced transitions in the metastable area near the critical temperatures (melting, structural transitions)

2000-01-01

5

Investigation of Moessbauer radiation diffraction on Fe/sub 3/BO/sub 6/ monocrystal. Nuclear transition interference  

Energy Technology Data Exchange (ETDEWEB)

Energy spectra of the Bragg reflection of the Moessbauer ..gamma..-radiation from the /sup 57/Fe/sub 3/BO/sub 6/ weakly ferromagnetic monocrystal are studied. A strong effect of the interference transitions in iron nuclei, being in non-equivalent positions, on the spectra form is revealed. The measurement results are compared with theoretical calculations.

1984-05-25

6

Alignment and alignment dynamics of nematic liquid crystals on Langmuir-Blodgett mono-layers  

CERN Document Server

Mono-layers of stearic and behenic acids deposited with the Langmuir-Blodgett technique, were used as aligning films in nematic liquid crystal cells. During the filling process the liquid crystal adopts a deformed quasi-planar alignment with splay-bend deformation and preferred orientation along the filling direction. This state is metastable and transforms with time into homeotropic once the flow has ceased. The transition is accompanied by formation of disclination lines which nucleate at the edges of the cell. The lifetime of the metastable splay-bend state was found to depend on the cell thickness. On heating, anchoring transition from quasi-homeotropic to degenerate tilted alignment in form of circular domains takes place near the transition to the isotropic phase. The anchoring transition is reversible with a small hysteresis.

1998-01-01

7

Nucleonic versus nuclear spin-isospin polarization  

International Nuclear Information System (INIS)

We compare standard nuclear polarization mechanisms, #DELTA#-hole-polarization and meson-exchange-current effects in the q-dependent quenching of isovector spin transitions. Calculations are performed for the M1-transition form factors of the 1"+ states in "4"8Ca (10.23 MeV) and "8"8Sr (3.48 MeV). We obtain a satisfactory description of both form factors if the repulsive part of the residual interaction in the #DELTA#-hole channel is of similar strength to that in the nucleon-hole channel. Meson-exchange currents lead to an enhancement of M1 transitions by an amount which is small in general, but sensitive to the particular nuclear state involved. (orig.).

8

A Topology-Changing Phase Transition and the Dynamics of Flavour  

CERN Document Server

In studying the dynamics of large N_c SU(N_c) gauge theory with fundamental quark flavours in the quenched approximation, we observe a novel phase transition at finite temperature. A quark condensate forms at finite quark mass, and the value of the condensate varies smoothly with the quark mass for generic region in parameter space. At a particular value of the quark mass, there is a finite discontinuity in the condensate's vacuum expectation value, corresponding to a first order phase transition. We study this using holography, the string dual being the geometry of N_c D3--branes at finite temperature, AdS_5-Schwarzschild times S^5, probed by a D7-brane. The D7-brane has topology R^4 times S^3 times S^1, and allowed solutions correspond to either the S^3 or the S^1 shrinking away in the interior of the geometry. The phase transition represents a jump between branches of solutions having these two ...

2006-01-01

9

Modular symmetry in parametrically excited quantum oscillators  

Energy Technology Data Exchange (ETDEWEB)

It is shown that when a quantum mechanical oscillator is parametrically excited there are special values of the parameters for which the system will pass periodically through a lattice of coherent states associated with the modular group [Gamma]. It is shown that these [Gamma] transits can be used to determine unknown parameters. A method is given for detecting the transits experimentally and is made possible by the existence of three families of states associated with modular forms that are orthogonal to the lattice. For isotropic states the three families occur in [ital D]-mode systems with [ital D][gt]10, 14, and 26.

1993-11-29

10

The transition of metallic crystals nanostructure into the nanostructure of metallic liquids  

International Nuclear Information System (INIS)

The evolution of metallic substance atomic structure is studied on temperature variation including crystal heating up to melting points, a crystal- liquid phase transition and initiation of a high-density liquid specific structure. It is marked that heat induced changes of simple metal structure can be described as changes around a natural elementary cell which is common for both a crystal and a liquid and consists of a central atom and Z_1 atoms of the first coordination sphere. On this basis the vacancy model of melting is verified. Concentrations of melting vacancies are determined by coordination numbers in the form of Z_1/(1+Z_1)"2 which are the same for both a crystal and a natural elementary cell. The size of natural elementary cells is in an agreement with that of the coordination sphere featured in the liquid and phase transition statistical theory. Calculated data are given for a number of metals, Cs, Eu, Ni, V ...

11

The thermal conductivity jump at crystal-liquid phase transition in CHCl3, C6H6, and CCl4: the action of rotational molecular motions  

International Nuclear Information System (INIS)

The thermal conductivity of liquid CHCl3, C6H6, and CCl4 is measured by a steady-state method under saturated vapor pressure in the temperature regions corresponding to pre-crystallization temperatures. The experimental results obtained are used to investigate the isobaric thermal conductivity jump ? ?p at the crystal-liquid phase transition in CHCl3, C6H6, and CCl4. The contributions of the phonon-phonon and phonon-rotational interaction to the total thermal resistance in solid and liquid state are specified using a modified method of reduced coordinates. The decrease in the thermal conductivity at the crystal-liquid phase transition, ? ?p, is explained by a combined effect of variations in positional distribution of molecules and in the form of rotational molecular motion.

2009-04-01

12

The thermal conductivity jump at crystal-liquid phase transition in CHCl3, C6H6, and CCl4: the action of rotational molecular motion  

Science.gov (United States)

The thermal conductivity of liquid CHCl3, C6H6, and CCl4 is measured by a steady-state method under saturated vapor pressure in the temperature regions corresponding to pre-crystallization temperatures. The experimental results obtained are used to investigate the isobaric thermal conductivity jump ??p at the crystal-liquid phase transition in CHCl3, C6H6, and CCl4. The contributions of the phonon-phonon and phonon-rotational interaction to the total thermal resistance in solid and liquid state are specified using a modified method of reduced coordinates. The decrease in the thermal conductivity at the crystal-liquid phase transition, ??p, is explained by a combined effect of variations in positional distribution of molecules and in the form of rotational molecular motion.

2009-04-01

13

Orbital ordering, ferroelasticity, and the large pressure induced volume collapse in PbCrO3  

CERN Document Server

We report a new tetragonal ground-state for perovskite-structured PbCrO3 from DFT+U calculations, and explain its anomalously large volume. The new structure is stabilized due to orbital ordering of Cr-d in the presence of a large tetragonal crystal field, mainly due to off-centering of the Pb atom. At higher pressures (smaller volumes) there is a first-order transition to a cubic phase where the Cr-d orbitals are orbitally liquid. This phase-transition is accompanied by a ~11.5% volume collapse, one of the largest known for transition-metal oxides. The large ferroelasticity and its strong coupling to the orbital degrees of freedom could be exploited to form potentially useful magnetostrictive materials

2011-01-01

14

Conformational analysis of ethyl azidoformate  

International Nuclear Information System (INIS)

A conformational analysis of ethyl azidoformate (EAF) has been carried out by the MINDO/3 quantum-chemical method. It has been shown that EAF exists in the form of two conformers differing with respect to rotation around the C-N bond. Complete optimization of the geometry has been carried out for both conformers. It has been found that the transoid conformation is planar and that the cisoid conformation is nonplanar. The height of the rotation barrier is 15.4 kcal/mole. The optimal geometry of the transition state has been calculated. It has been noted that a significant role in the mechanism of the conformational transition is played by the inversion of a nitrogen, which facilitates the transition. The results of the calculation have been confirmed by IR-spectroscopic data.

15

ISR Hadron Production in e+e- Annihilations and Meson-Photon Transition Form Factors  

CERN Document Server

We present several recent results from the BaBar collaboration in the areas of initial state radiation physics and transition form factors. An updated study of the processes e+e- -> K+K-pi+pi- and e+e- -> K+K-pi0pi0 provides an improved understanding of the Y(2175) meson. A very precise study of the process e+e- -> pi+pi- improves the precision on the calculated anomalous magnetic moment of the muon and provides by far the best information on excited rho states. Our previous measurements of the timelike transition form factors (TFF) of the eta and eta' mesons at Q^2=112 GeV^2, combined with new measurements of the their spacelike TFFs and those of the pi0 and eta_c mesons, provide powerful tests of QCD and models of the distribution amplitudes of quarks inside these mesons. The eta_c TFF shows the expected behavior over the Q^2 range 1-50 GeV^2, and we are sensitive to next-to-leading-order QCD ...

2011-01-01

16

Transitioning DARPA Technology  

Science.gov (United States)

Page 1. TRANSITIONING DARPA TECHNOLOGY ... Transitioning DARPA Technology JAMESJ.RJCHARDSON DIANE L. LARRNA ...

2001-05-01

17

Suppression of the transverse scattering amplitude in /sup 207/Pb  

Energy Technology Data Exchange (ETDEWEB)

Transverse form factors have been extracted for the low-lying neutron hole (particle) states of /sup 207/Pb from inelastic-electron-scattering data. A systematic, multipolarity-and momentum-transfer-independent quenching of approx.55% in the transverse amplitude is observed when compared with single particle predictions for both electric and magnetic transitions. The magnitude of the observed effect is not readily explained by our present theoretical understanding of this nucleus.

1980-07-14

18

Pseudostate description of breakup in the coupled-reaction-channel method: Numerical study of nonorthogonality effects  

Energy Technology Data Exchange (ETDEWEB)

To simulate the effects of the breakup channel on rearrangement amplitudes, the conventional coupled-reaction-channel (CRC) expansion is augmented by pseudoreaction channels. The construction of the projector for the extended CRC space is discussed, and transition-operator equations on this space are given. By solving the full and post-approximation forms of the CRC equations for a model three-particle problem, the crucial role played by the nonorthogonality terms is demonstrated.

1991-03-01

19

Pseudostate description of breakup in the coupled-reaction-channel method: Numerical study of nonorthogonality effects  

International Nuclear Information System (INIS)

To simulate the effects of the breakup channel on rearrangement amplitudes, the conventional coupled-reaction-channel (CRC) expansion is augmented by pseudoreaction channels. The construction of the projector for the extended CRC space is discussed, and transition-operator equations on this space are given. By solving the full and post-approximation forms of the CRC equations for a model three-particle problem, the crucial role played by the nonorthogonality terms is demonstrated.

20

Predictive wavefront control for Adaptive Optics with arbitrary control loop delays  

Energy Technology Data Exchange (ETDEWEB)

We present a modification of the closed-loop state space model for AO control which allows delays that are a non-integer multiple of the system frame rate. We derive the new forms of the Predictive Fourier Control Kalman filters for arbitrary delays and show that they are linear combinations of the whole-frame delay terms. This structure of the controller is independent of the delay. System stability margins and residual error variance both transition gracefully between integer-frame delays.

2007-10-30

21

The dependence of the temperature of crystal-liquid phase transition on the size and shape of simple nanocrystal  

British Library Electronic Table of Contents (United Kingdom)

The dependence of melting temperature T m on the size and shape of an n -dimensional nanocrystal of elementary single-component substance is studied. The nanocrystal has the form of an n-dimensional parallelepiped with a square base. The ratio of the length of side rib to the length of base rib (which is equal to f) defines the form of the system. It is demonstrated that, if the surface pressure is ignored, the value of T m decreases with isomorphic (f = const) decrease in the size of nanocrystal. In so doing, the more the value of form parameter f deviates from unity, the more appreciable the size dependence of T m will be. However, if the surface pressure (?Laplace pressure??) is taken into account in the case of decrease in size, the value of T m may vary significantly. In so doing, if ...

2009-01-01

22

Saturated bonds and anomalous electronic transport in transition-metal aluminides  

Energy Technology Data Exchange (ETDEWEB)

This thesis deals with the special electronic properties of the transition-metal aluminides. Following quasicrystals and their approximants it is shown that even materials with small elementary cells exhibit the same surprising effects. So among the transition-metal aluminides also semi-metallic and semiconducting compounds exist, although if they consist of classic-metallic components like Fe, Al, or Cr. These properties are furthermore coupled with a deep pseusogap respectively gap in the density of states and strongly covalent bonds. Bonds are described in this thesis by two eseential properties. First by the bond charge and second by the energetic effect of the bond. It results that in the caes of semiconducting transition-metal aluminides both a saturation of certain bonds and a bond-antibond alteration in the Fermi level is present. By the analysis of the near-order in form of the so-calles ...

2006-05-22

23

Spin transition in octahedral metal complexes containing tetraazamacrocyclic ligands  

British Library Electronic Table of Contents (United Kingdom)

This review focusses on spin crossover complexes with octahedral metal ions which are bound to a tetraazamacrocyclic ligand and additionally either to two monodentate ligands or to one bidentate ligand. Macrocyclic ligands with a sufficiently large ring size prefer to coordinate to metal ions in an equatorial fashion yielding trans-octahedral coordination environments. In contrast, twelve-membered tetraazamacrocycles with high steric rigidity, such as 2,11-diaza[3.3](2,6)pyridinophanes or 2,11-dithia[3.3](2,6)pyridinophane, are prone to form cis-octahedral complexes. While the electronic and the steric properties of the coordinated tetraazamacrocycle in trans-octahedral complexes are very likely responsible for the paucity of observed spin transitions, the cis-octahedral coordination mode ...

2009-01-01

24

Quark-hadron duality in neutrino scattering  

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}.

2006-07-24

25

Magnetic-field-induced phase transitions in Wigner molecules  

Energy Technology Data Exchange (ETDEWEB)

A theoretical analysis of formation and symmetry transformations is presented for Wigner molecules with N = 2,..., 20 electrons confined in quantum dots at high magnetic fields. Using the unrestricted Hartree-Fock method with the multicentre Gaussian basis, we have found that Wigner molecules with N {>=} 6 abruptly change their shape and symmetry with an associated jump in the first derivative of the ground-state energy, i.e. they undergo phase transitions. In particular, the phases of the Wigner molecules obtained just after emerging from the maximum-density droplet (MDD) phase possess a different symmetry from that formed at a high magnetic field. We show that the properties of the electron-electron interaction energy demonstrate very well both the breakdown of the MDD and the quasi-classical character of the Wigner molecule in the high magnetic field. Possible mechanisms of the MDD decay are discussed.

2003-06-25

26

Coherent spontaneous radiation of Frenkel excitons  

International Nuclear Information System (INIS)

We have constructed a mathematical model that describes the coherent spontaneous radiation of a macroscopically filled exciton mode. We have demonstrated qualitatively ways in which a coherent subsystem of excitons can be formed. When this occurs under the influence of an external coherent source, exciton free induction occurs, while in the case of a spontaneous transition of the excitons to a coherent state through freezing of the reservoir of intermolecular interactions superradiance occurs. We have concluded that superradiance in the system of Frenkel excitons is possible under the influence of the non-Dicke mechanisms of self-induction of correlations, when the dipole transition moments of the individual atoms are coupled into a single macroscopic effective spin through their electrostatic interaction, this being analogous to the ordering of magnetic dipole moments in a ferromagnet.

1988-01-01

27

Behavior of Np(VII, VI, V) in Silicate Solutions  

Energy Technology Data Exchange (ETDEWEB)

Spectrophotometric methods were used to investigate the properties of neptunium(VII), (VI), and (V) in silicate solution. The transition of cationic neptunium(VII) to anionic species in non-complexing environments proceeds in the range of ?? 5.5 to 7.5. In the presence of carbonate, this transition occurs at ?? 10.0 to 11.5 and in silicate solutions at ?? 10.5-12.0. These findings show that cationic neptunium(VII) forms complexes with both carbonate and silicate and that the silicate complex is stronger than that of the carbonate. The competition of complex formation reactions for neptunium(VI) with carbonate and silicate and on the known complex stability constant of NpO2(CO3)34- allowed the NpO2SiO3 complex stability constant, log ? = 16.5, to be estimated. Determination of the formation constant of Np(V) complexes with SiO32- was not possible using similar methods.

2004-11-30

28

A superconductor to superfluid phase transition in liquid metallic hydrogen  

CERN Document Server

Although hydrogen is the simplest of atoms, it does not form the simplest of solids or liquids. Quantum effects in these phases are considerable (a consequence of the light proton mass) and they have a demonstrable and often puzzling influence on many physical properties, including spatial order. To date, the structure of dense hydrogen remains experimentally elusive. Recent studies of the melting curve of hydrogen indicate that at high (but experimentally accessible) pressures, compressed hydrogen will adopt a liquid state, even at low temperatures. In reaching this phase, hydrogen is also projected to pass through an insulator-to-metal transition. This raises the possibility of new state of matter: a near ground-state liquid metal, and its ordered states in the quantum domain. Ordered quantum fluids are traditionally categorized as superconductors or superfluids; these respective systems feature dissipationless electrical currents or mass ...

2004-01-01

29

Transformation and Transition: DARPA's Role in Fostering an ...  

Science.gov (United States)

Transformation and Transition: DARPA's Role in Fostering an Emerging Revolution ... IDA Paper P-3698 Transformation and Transition: DARPA's ...

2003-11-01

30

Detections of SiO and H$_2$O Masers in the Bipolar Nebula IRAS 19312+1950  

CERN Document Server

We report on the detection of SiO and water masers toward a newly found bipolar nebula, IRAS 19312+1950. This object exhibits extreme red IRAS color log (F25/F12)=0.5 and log (F60/F25)=0.7 and a nebulosity having a size of about 30" extended to the South-West in the 2MASS near-infrared image. Toward this object, we have detected emission from the H2O 6(1,6)-5(2,3) transition, the SiO J=1-0, v=1 and 2, and J=2-1, v=1 transitions, and the SO 2(2)--1(1) and H13CN J=1-0 transitions. The thermal lines of SO and H13CN are shifted by about 12 km/s in radial velocity with respect to the maser lines, indicating that thermal emission comes from the background molecular cloud. However, the SiO J=2-1, v=2 spectrum shows another component of SiO emission separated by 26 km/s from the main component, that might be formed in a rotating or expanding shell.

2000-01-01

31

Composition, structure and evolution of neutron stars with kaon condensates  

International Nuclear Information System (INIS)

We investigate the possibility of kaon condensation in the dense interior of neutron stars through the s-wave interaction of kaons with nucleons. We include nucleon-nucleon interactions by using simple parametrizations of realistic forces, and include electrons and muons in #beta#-equilibrium. The equation of state above the condensate threshold is derived in the mean field approximation. The conditions under which kaon condensed cores undergo a transition to quark matter containing strange quarks are also established.The critical density for kaon condensation lies in the range (2.3-5.0)#rho#_0, where #rho#_0=0.16 fm"-"3 is the equilibrium density of nuclear matter. The critical density depends largely on the value of the strangeness content of the proton, the size of which is controversial. For too large a value of the strangeness content, matter with a kaon condensate is not sufficiently stiff to support the lower limit of 1.44 M_o_e_d_o_t for a neutron star. ...

32

Morphology and thermal properties of electrospun fatty acids/polyethylene terephthalate composite fibers as novel form-stable phase change materials  

Energy Technology Data Exchange (ETDEWEB)

The ultrafine fibers based on the composites of polyethylene terephthalate (PET) and a series of fatty acids, lauric acid (LA), myristic acid (MA), palmitic acid (PA), and stearic acid (SA), were prepared successfully via electrospinning as form-stable phase change materials (PCMs). The morphology and thermal properties of the composite fibers were studied by field emission scanning electron microscopy (FE-SEM) and differential scanning calorimetry (DSC), respectively. It was found that the average fiber diameter increased generally with the content of fatty acid (LA) in the LA/PET composite fibers. The fibers with the low mass ratio maintained cylindrical shape with smooth surface while the quality became worse when the mass ratio is too high (more than 100/100). Moreover, the latent heat of the composite fibers increased with the increase of LA content and the phase transition temperature of the fibers have no obvious variations compared with ...

2008-11-15

33

Measurement of the N{yields}{delta}{sup +}(1232) Transition at High-Momentum Transfer by {pi}{sup 0} Electroproduction  

Science.gov (United States)

We report a new measurement of the exclusive electroproduction reaction {gamma}*p{yields}{pi}{sup 0}p to explore the evolution from soft nonperturbative physics to hard processes via the Q{sup 2} dependence of the magnetic (M{sub 1+}), electric (E{sub 1+}), and scalar (S{sub 1+}) multipoles in the N{yields}{delta} transition. 9000 differential cross section data points cover W from threshold to 1.4 GeV/c{sup 2}, 4{pi} center-of-mass solid angle, and Q{sup 2} from 3 to 6 GeV{sup 2}/c{sup 2}, the highest yet achieved. It is found that the magnetic form factor G{sub M}* decreases with Q{sup 2} more steeply than the proton magnetic form factor, the ratio E{sub 1+}/M{sub 1+} is small and negative, indicating strong helicity nonconservation, and the ratio S{sub 1+}/M{sub 1+} is negative, while its magnitude increases with Q{sup 2}.

2006-09-15

34

In-Situ Analysis of Electronic Properties of Passive Film on Fe by Photo-Electrochemical and Impedance Techniques  

Energy Technology Data Exchange (ETDEWEB)

Electronic properties of passive films formed on Fe at various applied potentials in pH 8.5 buffer solution were examined through the photocurrent measurement and impedance spectroscopy. Passive film formed on Fe at relatively low potentials was found to be r-FeOOH layer and internal r-Fe{sub 2}O{sub 3} layer. However, the r-FeOOH layer became unstable and disappeared at potentials below 400mV and hence may be an adsorbed layer. An electronic band structure model for the passive film of Fe was suggested on the basis of the spinel band model with involving two types of electronic excitation processes, i. e., the p-d and the d-d transition together. The effects of applied potential on the photocurrent behaviors of the passive film on Fe were explained appropriately by separating the photocurrent spectra depending on the transition type. The Mott-Schottky behavior for the passive film on Fe and the ...

1999-04-01

35

Research on regimes transition of the boiling water two-phase flow in horizontal rectangular narrow heated channels  

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows: The heat transfer and flow in narrow channels has lots of advantages such as compact structure, high efficiency, design flexibility and so on. So it is widely used in the fields such as the new reactor core plate elements, the once-through stream generator, compact heat exchangers as well as electronic components. In recent years, more strong attentions have been attracted to the thermal-hydraulic characteristics and mechanism of the two-phase flow in narrow channels. As the flow regime characteristics of two-phase flow is fundamental one of them, the research on the two-phase flow regimes and the regime transitions in horizontal rectangular narrow heated channels can provide theoretical foundation and engineering directions to the whole research on the thermal-hydraulic characteristics and mechanism of the two-phase flow in narrow channels. The characteristics of two-phase flow regimes and regime transitions ...

2005-07-01

36

Research on regimes transition of the boiling water two-phase flow in horizontal rectangular narrow heated channels  

International Nuclear Information System (INIS)

Full text of publication follows: The heat transfer and flow in narrow channels has lots of advantages such as compact structure, high efficiency, design flexibility and so on. So it is widely used in the fields such as the new reactor core plate elements, the once-through stream generator, compact heat exchangers as well as electronic components. In recent years, more strong attentions have been attracted to the thermal-hydraulic characteristics and mechanism of the two-phase flow in narrow channels. As the flow regime characteristics of two-phase flow is fundamental one of them, the research on the two-phase flow regimes and the regime transitions in horizontal rectangular narrow heated channels can provide theoretical foundation and engineering directions to the whole research on the thermal-hydraulic characteristics and mechanism of the two-phase flow in narrow channels. The characteristics of two-phase flow regimes and regime transitions ...

2005-10-02

37

Experimental investigation of the KLL Auger spectrum of "8"8Sr from the EC-decay of "8"8Y  

International Nuclear Information System (INIS)

According to the calculations, intensity of the KL_1L_2("3P_0) Auger transition should drastically increase with increasing atomic number Z due to the relativistic effects. However, this behavior was experimentally proved only for very few elements. A lack of enough precise experimental data in the atomic number region Z<45 does not enable one to distinguish between relativistic and non-relativistic approaches in this region. Thus for Z=38 the KL_1L_2("3P_0/"1P_1) intensity ratio was determined with relative uncertainty of 63 % in the only measurement with external excitation. Here we present results of our investigation of the KLL Auger electron spectrum of "8"8Sr generated in the EC decay of "8"8Y (T_1_/_2= 106.6 d). Electron spectra were measured with the 11 eV instrumental resolution using a combined electrostatic spectrometer. The present value of the KL_2L_3("1D_2) absolute transition energy in Sr is higher by 7.4 eV (i.e. more than ...

2007-06-04

38

The fluorescence properties and NMR analysis of protopine and allocryptopine  

International Nuclear Information System (INIS)

The fluorescence properties of protopine and allocryptopine in aqueous and organic environments are described for the first time. The fluorescence of alkaloids and their pH-dependent interconversion to cationic forms (transannular interaction) were studied using steady-state and time-resolved fluorescence techniques. For the analysis of tricyclic base and cis/trans tetracyclic cations of the alkaloids, NMR and X-ray crystallography were used. - Highlights: ? We describe fundamental fluorescence characteristics of alkaloids protopine and allocryptopine. ? We analyzed the pH-dependent transitions and cis/trans isomerization. ? These two alkaloids can be better distinguished by their fluorescence decay characteristics. ? The fluorescence parameters are related to the NMR and crystallographic structural data.

2011-07-01

39

Mechanism of thermal excitation of the electron states of diatomic molecules behind a shock wave front  

Energy Technology Data Exchange (ETDEWEB)

Alternative mechanisms of electron state excitation in diatomic molecules are examined with reference to CN and C2 molecules forming in chemical reactions behind strong shock wave fronts in a CO(CO2)-N2 gas mixture. The temperature range considered is 4000-8000 K. An effective excitation mechanism is proposed which involves rapid vibration-rotation excitation at all electron states and nonradiative transitions between perturbed electron states induced by collisions with the ambient gas particles.

1981-03-01

40

Gravitational effect on liqui-fillet in horizontal agitated thin-film evaporators  

Energy Technology Data Exchange (ETDEWEB)

A liquid-fillet is formed in front of a rotor blade in the cylinder of a horizontal agitated thin-film evaporator. Its thickness varies due to the gravity while the blade revolves inside the cylinder. In the critical condition, the amplitude of the oscillation becomes infinite and the phase advances 180 degrees. Prior to the critical condition, the experimental data agrees fairly well with the predictions. Near the critical condition, the amplitutde increases and the phase advances 60 degrees. In other words, the transition to the critical condition occurs continuously. (6 figs, 1 ref)

1988-04-25

41

A human breast cell model of pre-invasive to invasive transition  

Energy Technology Data Exchange (ETDEWEB)

A crucial step in human breast cancer progression is the acquisition of invasiveness. There is a distinct lack of human cell culture models to study the transition from pre-invasive to invasive phenotype as it may occur 'spontaneously' in vivo. To delineate molecular alterations important for this transition, we isolated human breast epithelial cell lines that showed partial loss of tissue polarity in three-dimensional reconstituted-basement membrane cultures. These cells remained non-invasive; however, unlike their non-malignant counterparts, they exhibited a high propensity to acquire invasiveness through basement membrane in culture. The genomic aberrations and gene expression profiles of the cells in this model showed a high degree of similarity to primary breast tumor profiles. The xenograft tumors formed by the cell lines in three different microenvironments in nude mice displayed metaplastic ...

2008-03-10

42

Novel catalysts for methane activation. Final progress report, September 30, 1992--April 30, 1996  

Energy Technology Data Exchange (ETDEWEB)

This final report summarizes the results of our research under Contract No. DE-AC22-92PC92112, Novel Catalysts for Methane Activation. In this research we prepared and tested fullerene soots for converting methane into higher hydrocarbons. We conducted the methane conversions using dehydrocoupling conditions, primarily in the temperature regimes of 600{degrees}-1000{degrees}C and atmospheric pressures. The research was divided into three sections. The first section focused on comparing fullerene soots with other forms of carbon such as acetylene black and Norit-A. We found that the fullerene soot was indeed more reactive than the other forms of carbon. However, due to its high reactivity, it was not selective. The second section focused on the effect of metals on the reactivity of the soots, including both transition metals and alkali metals. We found that potassium could enhance the selectivities of fullerene soot to ...

1996-06-11

43

Capacitance behaviour of passive films on ferritic and austenitic stainless steel  

Energy Technology Data Exchange (ETDEWEB)

The electrochemical behaviour of passive films formed on one austenitic stainless steel (AISI 304) and one ferritic stainless steel (AISI 446) in solutions with pH between 0.6 and 8.4 was studied by capacitance measurements and photocurrent spectroscopy. Compositional characterization of the passive films was done by X-ray photoelectron spectroscopy. The capacitance increases with decreasing pH. Doping densities evaluated from Mott-Schottky plots are in the range 2-6 x 10{sup 20} cm{sup -3} and increased with the pH in the neutral/alkaline range while in pH 0.6, values above 10{sup 21} cm{sup -3} were found. The bandgap energy indicates two transitions, at 2.5-2.8 and 3.2 eV. The analytical data reveal that, as the pH increased, the films become enriched in Fe(II) and Fe(III), whereas the Cr(III) gradually decreases. The films formed at very low pH had a behaviour that contrasts with that of the films ...

2005-03-01

44

Capacitance behaviour of passive films on ferritic and austenitic stainless steel  

International Nuclear Information System (INIS)

The electrochemical behaviour of passive films formed on one austenitic stainless steel (AISI 304) and one ferritic stainless steel (AISI 446) in solutions with pH between 0.6 and 8.4 was studied by capacitance measurements and photocurrent spectroscopy. Compositional characterization of the passive films was done by X-ray photoelectron spectroscopy. The capacitance increases with decreasing pH. Doping densities evaluated from Mott-Schottky plots are in the range 2-6 x 10"2"0 cm"-"3 and increased with the pH in the neutral/alkaline range while in pH 0.6, values above 10"2"1 cm"-"3 were found. The bandgap energy indicates two transitions, at 2.5-2.8 and 3.2 eV. The analytical data reveal that, as the pH increased, the films become enriched in Fe(II) and Fe(III), whereas the Cr(III) gradually decreases. The films formed at very low pH had a behaviour that contrasts with that of the films formed in the ...

2005-03-01

45

Survey for Transiting Extrasolar Planets in Stellar Systems. II. Spectrophotometry and Metallicities of Open Clusters  

CERN Document Server

We present metallicity estimates for seven open clusters based on spectrophotometric indices from moderate-resolution spectroscopy. Observations of field giants of known metallicity provide a correlation between the spectroscopic indices and the metallicity of open cluster giants. We use \\chi^2 analysis to fit the relation of spectrophotometric indices to metallicity in field giants. The resulting function allows an estimate of the target-cluster giants' metallicities with an error in the method of \\pm0.08 dex. We derive the following metallicities for the seven open clusters: NGC 1245, [m/H]=-0.14\\pm0.04; NGC 2099, [m/H]=+0.05\\pm0.05; NGC 2324, [m/H]=-0.06\\pm0.04; NGC 2539, [m/H]=-0.04\\pm0.03; NGC 2682 (M67), [m/H]=-0.05\\pm0.02; NGC 6705, [m/H]=+0.14\\pm0.08; NGC 6819, [m/H]=-0.07\\pm0.12. These metallicity estimates will be useful in planning future extra-solar planet transit searches since planets may form more readily in metal-rich ...

2005-01-01

46

Self-consistent linearized augmented-plane-wave study of the electronic structure and superconductivity of fcc lanthanum under pressure  

International Nuclear Information System (INIS)

We report the results of a linearized augmented-plane-wave calculation of the electronic structure of fcc La at three lattice constants corresponding to ambient pressure, 50, and 120 kbars. The Kohn-Sham-Gaspar approximation for exchange and correlation is used and the potential is allowed a fully non-muffin-tin form. The f bands lie approx.2--2.5 eV above the Fermi level and are approx.1 eV wide, resulting in a very small (0.05 electrons) localized f occupation. Under pressure the f bands rise and broaden appreciably, resulting in only a slight increase in f occupation. The rigid-muffin-tin approximation for the electron-phonon interaction lambda overestimates the superconducting transition temperature T/sub c/ by 40%, but we find that the drastic increase in T/sub c/ under pressure can be attributed primarily to changes in the electronic stiffness eta. Structural transitions which occur at 25 and 53 kbars may be related ...

47

Microscopic analysis of the /sup 88/Sr(p,p') reaction at E/sub p/ = 201. 5 MeV  

Energy Technology Data Exchange (ETDEWEB)

Differential cross sections for 201.5 MeV proton scattering form /sup 88/Sr were measured. From the analysis of the elastic data, no unique optical-model potential could be obtained, but the radial moments are well determined. In a macroscopic analysis of the collective states it turns out that if the optical potential and transition potential are chosen consistently, unambiguous potential deformation lengths can be obtained even though the optical potential is not unique. Taking into account the range and density dependence of the underlying effective interaction reliable neutron deformation lengths can be obtained. For inelastic transitions of various character microscopic distorted-wave calculations with a density-dependent interaction based on the Paris potential were performed. The nuclear structure was taken from one broken-pair calculations in a large model space, calibrated by (e,e') data. In general a good ...

1988-04-25

48

Microscopic analysis of the "8"8Sr(p,p') reaction at E_p = 201.5 MeV  

International Nuclear Information System (INIS)

Differential cross sections for 201.5 MeV proton scattering form "8"8Sr were measured. From the analysis of the elastic data, no unique optical-model potential could be obtained, but the radial moments are well determined. In a macroscopic analysis of the collective states it turns out that if the optical potential and transition potential are chosen consistently, unambiguous potential deformation lengths can be obtained even though the optical potential is not unique. Taking into account the range and density dependence of the underlying effective interaction reliable neutron deformation lengths can be obtained. For inelastic transitions of various character microscopic distorted-wave calculations with a density-dependent interaction based on the Paris potential were performed. The nuclear structure was taken from one broken-pair calculations in a large model space, calibrated by (e,e') data. In general a good description ...

49

Development of transition metal semiconductors for photoelectrolysis of water. Final report  

Energy Technology Data Exchange (ETDEWEB)

This report discusses the development of transition metal oxide semiconductors for photoelectrolysis of water. More specifically, it involves preparation of TiO/sub 2/ films by sputtering and evaluating their physicochemical characteristics primarily as they relate to the behaviour of the films as photoanodes. Impedance, photoelectrochemical, and photoconduction properties of TiO/sub 2/ films sputtered in pure O/sub 2/ onto heated substrates have been determined as a function of O/sub 2/ pressure during sputtering, film thickness, Pt overcoating, and cathodic treatment. The capacitance data before cathodic treatment are of the form expected. The capacitance is essentially independent of potential, while for potentials increasingly cathodic of this value, the capacitance increases very rapidly. Cathodic treatment alters the impedance characteristics of the films but leads to either no detectible change in their photoelectrochemical properties or ...

1981-03-27

50

Application of realistic meson-exchange forces in the broken-pair model  

Energy Technology Data Exchange (ETDEWEB)

A G-matrix, derived from a meson-exchange potential in nuclear matter, is applied to finite, semi-magic nuclei. For the open shell the broken-pair model, which can accommodate many single-particle levels, is used. The excitations of the closed shell are treated as particle-hole states. Energy spectra and electromagnetic transition densities are calculated for /sup 88/Sr and /sup 58/Ni. The energies of the non-collective states are well described. Pairing correlations in the ground state have almost the correct strength in a multishell model space. To improve the energies of the collective 2/sup +/ and 3/sup -/ states the inclusion of core-polarisation effects in the force is required. Transition charge densities for collective states become strongly surface-peaked by core-polarisation effects, as is observed in experiments. The effects of pairing correlations and core polarisation on the magnetic form factor of the 3.486 ...

1985-03-11

51

Application of realistic meson-exchange forces in the broken-pair model  

International Nuclear Information System (INIS)

A G-matrix, derived from a meson-exchange potential in nuclear matter, is applied to finite, semi-magic nuclei. For the open shell the broken-pair model, which can accommodate many single-particle levels, is used. The excitations of the closed shell are treated as particle-hole states. Energy spectra and electromagnetic transition densities are calculated for "8"8Sr and "5"8Ni. The energies of the non-collective states are well described. Pairing correlations in the ground state have almost the correct strength in a multishell model space. To improve the energies of the collective 2"+ and 3"- states the inclusion of core-polarisation effects in the force is required. Transition charge densities for collective states become strongly surface-peaked by core-polarisation effects, as is observed in experiments. The effects of pairing correlations and core polarisation on the magnetic form factor of the 3.486 MeV 1"+ state in ...

54

Temperature-induced fusion of small unilamellar vesicles formed from saturated long-chain lecithins and diheptanoylphosphatidylcholine  

Energy Technology Data Exchange (ETDEWEB)

Small unilamellar vesicles which form when gel-state long-chain phosphatidylcholines are mixed with micellar short-chain lecithins undergo an increase in size as the long-chain species melts to its liquid-crystalline form. Analysis of the vesicle population with quasi-elastic light scattering shows that the particle size increases from 90-A radius to greater than 5000-A radius. Resonance energy transfer experiments show total mixing of lipid probes with unlabeled vesicles only when the Tm of the long-chain phosphatidylcholine is exceeded. This implies that the large size change represents a fusion process. Aqueous compartments are also mixed during this transition. 31P NMR analysis of the vesicle mixtures above the phase transition shows a great degree of heterogeneity with large unilamellar particles coexisting with oligo- and multilamellar structures. Upon cooling the vesicles below the Tm, the ...

1989-10-03

56

Zirconium for superior corrosion resistance  

International Nuclear Information System (INIS)

Zirconium is a transition element located along with sister elements titanium and hafnium in Group IVB of the periodic table. It is grayish white metal, with a density somewhat less than carbon steel. Zirconium is the ninth most common metallic element in the earth's crust, and is more abundant than zinc, lead, nickel, or even copper. Zirconium is exceptionally resistant to corrosion by many common acids and alkalis. It is resistant to most organic acids, such as formic, acetic, lactic, and oxalic acids. It also has a high resistance to localized forms of corrosion, such as pitting, crevice corrosion, and stress corrosion cracking. Its corrosion resistance is caused by the formation of a dense, tenaciously adherent, chemically inert oxide film on the surface. This oxide film protects the base metal from both chemical and mechanical attack at temperatures up to about 400 C (750 F). This article describes zirconium's formability, machinability, ...

57

Synthesis, Characterization and Biological Properties of Anions of Bivalent Transition Metal [Co(II) and Ni(II)] Complexes With Acylhydrazine Derived ONO Donor Schiff Bases.  

Science.gov (United States)

Some acylhydrazine derived ONO donor Schiff bases and their Co(II) and Ni(II) complexes have been prepared having the same metal ion (cation) but different anions. These synthesized metal(II) complexes have been characterized on the basis of their elemental analyses, magnetic moment, molar conductance, and IR and electronic spectral data. All of the Schiff base ligands function as tridentates and the deprotonated enolic form is preferred for coordination. In order to evaluate the effect of anions on the bactericidal activity, these synthesized complexes, in comparison to the uncomplexed Schiff bases have been screened against bacterial species., Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa and the results are reported. PMID:18475936

2000-01-01

58

Study of Zircaloy-2 corrosion in high temperature water using ion beam methods  

Energy Technology Data Exchange (ETDEWEB)

Experiments have been carried out in water at 355 C to study transport of oxygen and hydrogen (as deuterium) in growing corrosion films. Composition of the films was also examined in 2.9 Mev and 3.9 Mev /alpha/-particle backscattering experiments. Corrosion occurs predominantly by oxygen diffusion through the film via grain boundary or similar short circuit diffusion paths, to form fresh oxide at the oxide metal interface. Increasing grain size within thick pre-breakaway films contributes to a decrease in diffusivity. The rate transition results from the generation of new diffusion pathways in previously protective oxide. Unexpectedly high concentrations of deuterium were observed. 26 refs.

1981-10-01

59

Structures and properties of functional metal iodates  

British Library Electronic Table of Contents (United Kingdom)

Metal iodates with a lone-pair containing I(V) that is in an asymmetric coordination geometry can form a diversity of unusual structures and many of them are promising new second homonic generation (SHG) materials. They exhibit wide transparency wavelength regions, large SHG coefficients and high optical-damage thresholds as well as moderately high thermal stability. In this paper, the structures and properties of the metal iodates are reviewed. The combination of d0 transition-metal cations with the iodate groups afforded a large number of metal iodates, with cations covering alkali metal, alkaline earth and lanthanide elements. Many of them are noncentrosymmetric (NCS) and display excellent SHG properties due to the additive effects of polarizations from both types of the asymmetric unit...

2011-01-01

60

Quantum Liquid Crystal Phases in Fermionic Superfluids with Pairing between Fermion Species of Unequal Densities  

CERN Document Server

Superfluidity in fermionic systems originates from pairing of fermions, and Bose condensation of these so-called Cooper pairs. The Cooper pairs are usually made of fermions of different species; for example in superconductors they are pairs of electrons with opposite spins. Thus the most favorable situation for pairing and superfluidity is when the two species of fermions that form pairs have the same density. This paper studies the possible superfluid states when the two pairing species have different densities, and show that the resultant states have remarkable similarities to the phases of liquid crystals. This enables us to provide a unified description of the possible pairing phases, and understand the phase transitions among them.

2005-01-01

61

Physicochemical investigation of the behavior of elements in chloride melts in the presence of solid phases based on phosphates of polyvalent elements. II. Behavior of strontium and barium  

Energy Technology Data Exchange (ETDEWEB)

The distribution of the alkaline earth elements strontium and barium between the solid phases of phosphates of transition elements of group 4 and chloride melts was studied. The distribution coefficients of strontium and barium were found at T = 700-800/sup 0/C. Phosphates of the type NaM/sub 2//sup (IV)/(PO/sub 4/)/sub 3/, where M/sub (IV)/ represents titanium, zirconium, and hafnium, were used as the solid phases. It was established that there is an enrichment of the precipitates with the distributed components. The distribution coefficient depends on the nature of the solid phase and the temperature. It was suggested that M/sup (II)/ x M/sub 4//sup (IV)/(PO/sub 4/)/sub 6/ is formed in processes of distribution, where M/sup (II)/ represents Sr, Ba.

1987-07-01

62

Magnetic and superconducting phases of CePd{sub 2}Si{sub 2}  

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.).

1996-07-01

63

Magnetic and superconducting phases of CePd_2Si_2  

International Nuclear Information System (INIS)

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_2Si_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.).

64

Influence of shape on ordering of granular systems in two dimensions  

Energy Technology Data Exchange (ETDEWEB)

We investigate ordering properties of two-dimensional granular materials using several shapes created by welding ball bearings together. Ordered domains form much more easily in two than in three dimensions, even when configurations lack long-range order. The onset of ordered domains occurs near a packing density of 0.8, a phenomenon observed previously for disks. One of our shapes, the trapezoid, has packings that remain disordered and near the transition density even after annealing by shaking. Although random packings are unstable for disks and many other shapes in two dimensions, trapezoid packings provide an approach to studying two-dimensional randomness. We also find that the rotational symmetry of a shape is an excellent predictor of how easily it orders, and a potential guide to identifying two-dimensional shapes that remain random after annealing.

2001-06-01

65

Inflation and reheating in Bianchi type-IX cosmology  

Energy Technology Data Exchange (ETDEWEB)

Within the framework of the Bianchi type-IX homogeneous space, we set up a system of coupled equations for the cosmic scale factors, scalar field, and radiative energy density. At the tree level, the equations are written in a self-consistent, Hartree-Fock form. For phi/sup 4/ theory, the system of nine first-order differential equations is solved numerically for a varying ratio of the energy of anisotropy to the vacuum energy. As the vacuum energy increases, there appears to be less reheating, since the energy of anisotropy is more efficiently converted into isotropic expansion. If the energy of anisotropy is large enough, the inflationary phase is prevented. In this case, a series of cosmological phase transitions will take place each time the square of the effective mass changes its sign.

1985-02-15

66

Inflation and reheating in Bianchi type-IX cosmology  

International Nuclear Information System (INIS)

Within the framework of the Bianchi type-IX homogeneous space, we set up a system of coupled equations for the cosmic scale factors, scalar field, and radiative energy density. At the tree level, the equations are written in a self-consistent, Hartree-Fock form. For phi"4 theory, the system of nine first-order differential equations is solved numerically for a varying ratio of the energy of anisotropy to the vacuum energy. As the vacuum energy increases, there appears to be less reheating, since the energy of anisotropy is more efficiently converted into isotropic expansion. If the energy of anisotropy is large enough, the inflationary phase is prevented. In this case, a series of cosmological phase transitions will take place each time the square of the effective mass changes its sign.

67

Feasibility investigations of growing and characterizing gallium arsenide crystals in ribbon form. Quarterly progress report 1 Jan-31 Mar 1975  

International Nuclear Information System (INIS)

The feasibility of continuous production of gallium arsenide ribbon single crystals, by passage of a molten zone through boron-oxide encapsulated GaAs feedstock, is being investigated. Polycrystalline GaAs ribbons have been grown in graphite boats by passage of a wide zone through B2O3-encapsulated feed-stock, confined by a quartz cover plate. Failure to remove the encapsulant above its glass transition temperature, however, resulted in cracking of the ribbons on cooling to room temperature. In order to study the crucial zone melting step in isolation from the encapsulation steps of the continuous process, a constrained-zone melting apparatus has been constructed in which the boron oxide serves only as a sealant to suppress arsenic vaporization. Large grained polycrystalline samples have been produced with this apparatus.

68

Epidemic spreading with nonlinear infectivity in weighted scale-free networks  

CERN Document Server

In this paper, we investigate the epidemic spreading for SIR model in weighted scale-free networks with nonlinear infectivity, where the transmission rate in our analytical model is weighted. Concretely, we introduce the infectivity exponent $\\alpha$ and the weight exponent $\\beta$ into the analytical SIR model, then examine the combination effects of $\\alpha$ and $\\beta$ on the epidemic threshold and phase transition. We show that one can adjust the values of $\\alpha$ and $\\beta$ to rebuild the epidemic threshold to a finite value, and it is observed that the steady epidemic prevalence $R$ grows in an exponential form in the early stage, then follows hierarchical dynamics. Furthermore, we find $\\alpha$ is more sensitive than $\\beta$ in the transformation of the epidemic threshold and epidemic prevalence, which might deliver some useful information or new insights in the epidemic spreading and the correlative immunization schemes.

2009-01-01

69

Dynamics of spontaneous radiation of atoms scattered by a resonance standing light wave  

International Nuclear Information System (INIS)

The scattering of atoms by a resonance standing light wave is considered under conditions when the lower of two resonance levels is metastable, while the upper level rapidly decays due to mainly spontaneous radiative transitions to the nonresonance levels of an atom. The diffraction scattering regime is studied, when the Rabi frequency is sufficiently high and many diffraction maxima are formed due to scattering. The dynamics of spontaneous radiation of an atom is investigated. It is shown that scattering slows down substantially the radiative decay of the atom. The regions and characteristics of the power and exponential decay are determined. The adiabatic and nonadiabatic scattering regimes are studied. It is shown that the wave packets of atoms in the metastable and resonance excited states narrow down during scattering. A limiting (minimal) size of the wave packets is found, which is achieved upon nonadiabatic scattering in the case of a ...

2003-09-01

70

Conversion of ortho-para H2O isomers in water and a jump in erythrocyte fluidity through a microcapillary at a temperature of 36.6?0.3?C  

British Library Electronic Table of Contents (United Kingdom)

A mechanism is proposed for the previously observed [1] jump in erythrocyte fluidity through a microcapillary 1.3 ?m in diameter at a temperature of 36.6?0.3?C. Our interpretation is based on the experimental evidence both for existence of ortho and para H2O isomers in water and on spin-selective interaction of proteins with para H2O isomers as hydration shells of biomolecules are being formed [2]. It is important that the formation of hydration shells of proteins and DNA in aqueous solutions is accompanied by an increase in the Brillouin shift to 0.4 cm?1 (?0.25 cm?1 in water), which points to the formation of icelike structures. We believe that the coincidence of the translational energy kT of the Brownian motion and the energy of the rotational quanta for the 313?202 transition of para ...

2009-01-01

71

Conformity, political participation, and economic rewards: The case of Chinese private entrepreneurs  

British Library Electronic Table of Contents (United Kingdom)

Using institutional and resource dependence theories as the conceptual framework, this study identifies three forms of conformity?political, economic, and social?that can affect the level of private entrepreneurs? formal political participation in a transition economy. Data from a 2004 national-wide survey of 3,012 private firms in China show that political conformity (indicated by membership in the ruling party), economic conformity (amount of taxes paid), and social conformity (amount of charity donated) are each antecedents to private entrepreneurs? formal political participation. Moreover, political conformity negatively moderates the relationship between social conformity and private entrepreneurs? formal political participation?for party members, a lesser amount of charity is associa...

2011-01-01

72

Computational study of non-stationary cluster size distribution and rate of nucleation in case of pre-existing clusters  

International Nuclear Information System (INIS)

The dynamics of a cluster-type system formed by constant total number of molecules, M, is studied when clusters change their sizes by nearest-size transitions (the Szilard model) with time-dependent boundary conditions and non-zero initial cluster size distribution. We compare these results to those reported previously, when non-stationary cluster size distribution was considered under the condition that only monomers are present in the system at the initial moment t=0, and describe the effect of arbitrary pre-existing clusters on the time evolution of the interacting clusters with different sizes, n. The average group size problem is also solved, and the process of relaxation in the system is studied. authors)

73

Bubble nucleation, growth and coalescence during the 1997 Vulcanian explosions of Soufriere Hills Volcano, Montserrat  

British Library Electronic Table of Contents (United Kingdom)

Soufriere Hills Volcano had two periods of repetitive Vulcanian activity in 1997. Each explosion discharged the contents of the upper 0.5-2km of the conduit as pyroclastic flows and fallout: frothy pumices from a deep, gas-rich zone, lava and breadcrust bombs from a degassed lava plug, and dense pumices from a transition zone. Vesicles constitute 1-66vol.% of breadcrust bombs and 24-79% of pumices, all those larger than a few tens of m being interconnected. Small vesicles (few hundreds of m) in pumices are interpreted as pre-dating explosion, implying pre-explosive conduit porosities up to 55%. About a sixth of large vesicles in pumices, and all those in breadcrust bombs, are angular voids formed by syn-explosive fracturing of amphibole phenocrysts. An intermediate-sized vesicle population...

2010-01-01

74

Baxter Q-operator and Separation of Variables for the open SL(2,R) spin chain  

CERN Document Server

We construct the Baxter Q-operator and the representation of the Separated Variables (SoV) for the homogeneous open SL(2,R) spin chain. Applying the diagrammatical approach, we calculate Sklyanin's integration measure in the separated variables and obtain the solution to the spectral problem for the model in terms of the eigenvalues of the Q-operator. We show that the transition kernel to the SoV representation is factorized into the product of certain operators each depending on a single separated variable. As a consequence, it has a universal pyramid-like form that has been already observed for various quantum integrable models such as periodic Toda chain, closed SL(2,R) and SL(2,C) spin chains.

2003-01-01

75

Alignment of nematic liquid crystals on mixed Langmuir-Blodgett mono-layers  

CERN Document Server

Mono-layers of stearic and behenic acids and mixtures of them in different proportions, deposited with the Langmuir-Blodgett technique, were used to study the alignment and the alignment dynamics in nematic liquid crystal cells. A relaxation process from a splay-bend flow induced metastable orientation to the homeotropic one occurs. The lifetime of the metastable state was found to depend on the mono-layer composition. The transition between the homeotropic and the conical anchoring was found to be irreversible in the case of the mixed aligning mono-layers: on cooling from the isotropic phase a quasi-planar nematic state (schlieren texture) appears. It is stable in a range of a few degrees below the clearing point and, on decreasing the temperature, relaxes to the homeotropic state in form of expanding domains.

1998-01-01

76

A novel electrochemical alkylation of aniline with methanol over Zn/Cu salts modified kaolin  

British Library Electronic Table of Contents (United Kingdom)

A novel liquid phase alkylation of aniline with methanol over Zn/Cu salts modified kaolin assisted with a pair of porous carbon electrode in slurry-bed reactor under constant current intensity, room temperature and atmospheric pressure was reported. The Zn/Cu salts modified kaolin catalysts were synthesized and characterized by infrared spectrometer (IR), powder X-ray diffraction (XRD) and scanning electron microscopy (SEM), which showed that the transition metals were completely supported on kaolins structure and formed a pored one. The effect parameters, such as initial pH, electrolysis time, metal ratio with kaolin and salts composition in this electrochemical catalytic system, were studied. The procedure was inspected by ultraviolet-visible spectrum (UV-vis), and the product distributi...

2008-01-01

77

Variations in humanized and defined culture conditions supporting derivation of new human embryonic stem cell lines  

DEFF Research Database (Denmark)

The evolution of "humanized" (i.e., free of animal sourced reagents) and ultimately chemically defined culture systems for human embryo stem cell (hESC) isolation and culture is of importance to improving their efficacy and safety in research and therapeutic applications. This can be achieved by integration of a multitude of individual approaches to replace or eliminate specific animal sourced reagents into a single comprehensive protocol. In the present study our objective was to integrate strategies obviating reliance on some of the most poorly defined and path-critical factors associated with hESC derivation, namely the use of animal immune compliment to isolate embryo inner cell mass, and animal sourced serum products and feeder cells to sustain hESC growth and attachment. As a result we report the derivation of six new hESC lines isolated by outgrowth from whole blastocysts on an extracellular matrix substrate of purified human laminin (Ln) with transitional ...

2006-01-01

78

Spectroscopy of /sup 87,88,89/Sr with (n,. gamma. ) and (d,p) reactions  

Science.gov (United States)

Over the recent years the nuclear structure around the N = 50 shell closure, which is very pronounced in the strontium and zirconium isotopes, has been the subject of extensive experimental and theoretical work. On the proton side Z = 38 and Z = 40 provide fairly closed sub-shells. In the strontium isotopes the lg/sub 9/2/ neutron shell is closed at /sup 88/Sr, supplying relatively pure neutron-hole and neutron-particle states with large spectroscopic factors in /sup 87/Sr and /sup 89/Sr, as well as core-coupled states. The mass region is thus ideally suited to examine the transition from a correlated to an uncorrelated (chaotic.) excitational behavior. These two types are characterized e.g. by the density of excited states, the transition strengths, and the spectroscopic factors observed in transfer reactions. We conducted (n,..gamma..) and (d,p) reactions leading to /sup 87,88,89/Sr in addition to /sup 88/Sr(d,t)/sup 87/Sr and 24 keV neutron ...

1988-01-01

79

Spectroscopy of /sup 87,88,89/Sr with (n,#gamma#) and (d,p) reactions  

International Nuclear Information System (INIS)

Over the recent years the nuclear structure around the N = 50 shell closure, which is very pronounced in the strontium and zirconium isotopes, has been the subject of extensive experimental and theoretical work. On the proton side Z = 38 and Z = 40 provide fairly closed sub-shells. In the strontium isotopes the lg/sub 9/2/ neutron shell is closed at "8"8Sr, supplying relatively pure neutron-hole and neutron-particle states with large spectroscopic factors in "8"7Sr and "8"9Sr, as well as core-coupled states. The mass region is thus ideally suited to examine the transition from a correlated to an uncorrelated (chaotic?) excitational behavior. These two types are characterized e.g. by the density of excited states, the transition strengths, and the spectroscopic factors observed in transfer reactions. We conducted (n,#gamma#) and (d,p) reactions leading to /sup 87,88,89/Sr in addition to "8"8Sr(d,t)"8"7Sr and 24 keV neutron capture in "8"8Sr. The ...

1988-04-24

80

Optical properties of crystalline and non-crystalline iron oxide thin films deposited by spray pyrolysis  

International Nuclear Information System (INIS)

Crystalline and non-crystalline iron oxide (#alpha#-Fe_2O_3) thin films were obtained by spray pyrolysis onto glass substrate at different temperatures. The results of X-ray diffraction showed that with increasing the deposition time, the film structure changed from non-crystalline to crystalline at the same substrate temperature. At different substrate temperatures and low deposition times (5 min), iron oxide appears almost in non-crystalline form. With rising the substrate temperature and deposition time, the crystallinity was improved. The effect of substrate temperature as well as deposition time on the optical features (absorption coefficient and bandgap) and optical constants of these films has been investigated. Optical constants of the films were determined from spectrophotometric measurement of reflectance and transmittance. Analysis of the results showed that, for non-crystalline iron oxide films of different thicknesses (76-118 nm) deposited at ...

2004-06-30

81

Radiation damage studies on CrO_4"2"- doped alums  

International Nuclear Information System (INIS)

Radiation damage studies have been carried out on undoped and CrO_4"2"- doped potassium and ammonium alums. The optical absorption bands observed around 27100 and 36500 cm"-"1 before irradiation have been attributed to the transitions t_1 #-># e and t_1 #-># t_2, on the basis of Ball-hausen and Liehr scheme. On prolonged X-irradiation, these bands disappear in both the alums and three new bands seem to grow in ammonium alum while only two new bands could be seen in potassium alum. EPR studies at RT reveal that there are two lines at g = 2.004 and g = 2.010 in ammonium alum and only one line at g = 2.004 in potassium alum. Besides these two nearly isotropic lines, there is a set of lines around g = 1.95 in both the alums. Correlating the optical and EPR studies it is concluded that SO_3"- and O_3"- centres have formed on X-irradiation in ammonium alum while only SO_3"- seems to have formed in potassium alum. The most ...

82

New dioxomolybdenum(VI) complexes with tridentate dibasic ONO donor schiff bases  

International Nuclear Information System (INIS)

Several dioxomolybdenum(VI) complexes of the schiff bases derived from salicylaldehyde, 2-hydroxy-1-naphthaldehyde, o-hydroxyacetophenone or pyridoxal and o-aminobenzylalcohol, o-aminophenol, o-hydroxybenzylamine, o-hydroxy(methylbenzyl)amine or 3-amino-2-naphthoic acid have been synthesized and characterized by elemental analysis, electrical conductance, molecular weight, IR and electronic spectral and magnetic susceptibility measurements. The schiff bases behave as dibasic, tridentate ligands and coordinate through ONO donor system forming complexes of the type MoO_2L.X (where LH_2=schiff base, X=H_2O or Ch_3OH). The compounds MoO_2L.Ch_3OH react with 2,2'-dipyridyl to form heterochelates of the type MoO_2L.dipyridyl. The complexes are non-electrolytes, monomers, diamagnetic and possess a cis-MoO_2 structure. The complexes exhibit a ligand-to-metal charge-transfer transition around 25000 cm"-"1. The complexes MoO_2L.X and ...

83

Lyman-alpha emitters as tracers of the transitioning Universe  

CERN Document Server

Of the many ways of detecting high redshift galaxies, the selection of objects due to their redshifted Ly-alpha emission has become one of the most successful. But what types of galaxies are selected in this way? Until recently, Ly-alpha emitters were understood to be small star-forming galaxies, possible building-blocks of larger galaxies. But with increased number of observations of Ly-alpha emitters at lower redshifts, a new picture emerges. Ly-alpha emitters display strong evolution in their properties from higher to lower redshift. It has previously been shown that the fraction of ultra-luminous infrared galaxies (ULIRGs) among the Ly-alpha emitters increases dramatically between redshift three and two. Here, the fraction of AGN among the LAEs is shown to follow a similar evolutionary path. We argue that Ly-alpha emitters are not a homogeneous class of objects, and that the objects selected with this method reflect the general star forming ...

2011-01-01

84

High Velocity Molecular Outflows In Massive Cluster Forming Region G10.6-0.4  

CERN Document Server

We report the arcsecond resolution SMA observations of the $^{12}$CO (2-1) transition in the massive cluster forming region G10.6-0.4. In these observations, the high velocity $^{12}$CO emission is resolved into individual outflow systems, which have a typical size scale of a few arcseconds. These molecular outflows are energetic, and are interacting with the ambient molecular gas. By inspecting the shock signatures traced by CH$_{3}$OH, SiO, and HCN emissions, we suggest that abundant star formation activities are distributed over the entire 0.5 pc scale dense molecular envelope. The star formation efficiency over one global free-fall timescale (of the 0.5 pc molecular envelope, $\\sim$10$^{5}$ years) is about a few percent. The total energy feedback of these high velocity outflows is higher than 10$^{47}$ erg, which is comparable to the total kinetic energy in the rotational motion of the dense molecular envelope. From order-of-magnitude ...

2010-01-01

85

Upper Paleozoic petroleum system, Ordos Basin, China  

Energy Technology Data Exchange (ETDEWEB)

The Ordos Basin is a typical lapped basin, including three sequences of strata: early Paleozoic, late Paleozoic and Mesozoic, with a total thickness of 4000-6000m. Impermeable sealing beds are well developed at the top and base of the upper Paleozoic sequence, separating it from the Mesozoic and the lower Paleozoic strata to form an independent petroleum system. In this petroleum system, the source rocks are widely distributed coals and dark mudstones occurring in the Carboniferous-lower Permian coal measures, with a thickness of 10-15 and 40-60m, respectively. The reservoirs are mainly early Permian tight sandstones, mostly with a porosity of 4-8% and a permeability of 0.1-1.0x10{sup -3}{mu}m{sup 2}. The regional cap rock is a 100-150m thick mudstone in the upper Permian strata. The structural framework of the basin is a huge asymmetric syncline, dipping gently toward the east and north, and steeply toward the south and west. Well data show that gas-saturated, ...

2005-09-01

86

Interaction of antimicrobial peptides with lipid membranes  

International Nuclear Information System (INIS)

This study aims to investigate the difference in the interaction of antimicrobial peptides with two classes of zwitterionic peptides, phosphatidylethanolamines (PE) and phosphatidylcholines (PC). Further experiments were performed on model membranes prepared from specific bacterial lipids, lipopolysaccharides (LPS) isolated from Salmonella minnesota. The structure of the lipid-peptide aqueous dispersions was studied by small-and wide-angle X-ray diffraction during heating and cooling from 5 to 85 C. The lipids and peptides were mixed at lipid-to-peptide ratios 10-10000 (POPE and POPC) or 2-50 (LPS). All experiments were performed at synchrotron soft condensed matter beamline A2 in Hasylab at Desy in Hamburg, Germany. The phases were identified and the lattice parameters were calculated. Alamethicin and melittin interact in similar ways with the lipids. Pure POPC forms only lamellar phases. POPE forms lamellar phases at low temperatures that ...

87

A Profile of Defense Manufacturing Costs and Enabling ...  

Science.gov (United States)

... Casting Explosive forming Forging Electrohydraulic forming Extruding Magnetic forming Rolling Electroforming Drawing Powdered metal forming ...

1992-01-01

88

(Form for)  

Wastenet

Date: Cost: Allocation:

89

Uneven dietary development: linking the policies and processes of globalization with the nutrition transition, obesity and diet-related chronic diseases  

UK PubMed Central (United Kingdom)

In a "nutrition transition", the consumption of foods high in fats and sweeteners is increasing throughout the developing world. The transition, implicated in the rapid rise of obesity and diet-related...Full Text Available

90

The Transition to High School: Current Knowledge, Future Directions  

UK PubMed Central (United Kingdom)

In the American educational system, school transitions are frequent and predictable, but they can disrupt student functioning across developmental domains. How students experience school transitions...Full Text Available

2011-04-01

91

On the possibilities of a phase transition of superconducting type in the gross-Neveu model  

Energy Technology Data Exchange (ETDEWEB)

It is shown that calculation of the anomalous expectation values for the massless Gross-Neveu model in the Hartree-Fock approximation indicates the presence of an ordinary chiral phase transition if the coupling constant has the normal sign (g > 0) and of a different transition of the superconductivity type if g < 0.

1995-11-01

92

On Phase Transition of Compressed Sensing in the Complex Domain  

CERN Document Server

The phase transition is a performance measure of the sparsity-undersampling tradeoff in compressed sensing (CS). This letter reports, for the first time, the existence of an exact phase transition for the $\\ell_1$ minimization approach to the complex valued CS problem. This discovery is not only a complementary result to the known phase transition of the real valued CS but also shows considerable superiority of the phase transition of complex valued CS over that of the real valued CS. The results are obtained by extending the recently developed ONE-L1 algorithms to complex valued CS and applying their optimal and iterative solutions to empirically evaluate the phase transition.

2011-01-01

93

The quasimolecular model in transitional nuclei  

International Nuclear Information System (INIS)

A review is made of some recent developments in the application of the Bohr Hamiltonian to transitional nulcei. The primary concern is to understand the advantages and limitations inherent to the basic model and its many variants. (author).

94

The influence of tertiary structural restraints on conformational transitions in superhelical DNA.  

UK PubMed Central (United Kingdom)

This paper examines theoretically the effects that restraints on the tertiary structure of a superhelical DNA domain exert on the energetics of linking and the onset of conformational transitions. The...Full Text Available

1987-12-10

95

Spectroscopy of a narrow-line laser cooling transition in atomic dysprosium  

CERN Document Server

The laser cooling and trapping of ultracold neutral dysprosium has been recently demonstrated using the broad, open 421-nm cycling transition. Narrow-line magneto-optical trapping of Dy on longer wavelength transitions would enable the preparation of ultracold Dy samples suitable for loading optical dipole traps and subsequent evaporative cooling. We have identified the closed 741-nm cycling transition as a candidate for the narrow-line cooling of Dy. We present experimental data on the isotope shifts, the hyperfine constants A and B, and the decay rate of the 741-nm transition. In addition, we report a measurement of the 421-nm transition's linewidth, which agrees with previous measurements. We summarize the laser cooling characteristics of these transitions as well as other narrow cycling transitions that may prove useful for cooling Dy.

2010-01-01

96

Science of quantum phase transitions and quantum criticalities  

International Nuclear Information System (INIS)

Apart from conventional phase transitions driven by the thermal effects, quantum phase transitions generated by quantum fluctuations have their own mechanisms that are reflected in critical phenomena. Quantum phase transitions have an origin from spontaneous symmetry breaking commonly to thermal phase transitions. Even in this case, inherent quantum fluctuations substantially modify and yield new aspects. Quantum phase transitions have, however, another mechanism caused by topology changes, which gives completely new characters. Recently, a mechanism which connects these two has been found. Proimities from first-order transitions and phase separatins as well as from multiphase coexistence also generate characteristic and unconventional quantum criticalities. Understanding novel quantum criticalities offers a firm basis of recent active researches on fields such ...

2011-02-01

97

Psychomotor Vigilance Test (PVT) Transition to Operations - HRR - Task  

Science.gov (United States)

Task, Psychomotor Vigilance Test (PVT) Transition to Operations ... Related Tasks (36). Task, Psychomotor Vigilance Test (PVT) on ISS. Common Item(s) ...

98

New York City Transit Hybrid and CNG Transit Buses: Final Evaluation Results  

Energy Technology Data Exchange (ETDEWEB)

This report describes the evaluation results for new Orion VII buses at NYCT with CNG propulsion and new hybrid propulsion.

2006-11-01

99

NSSC Transition Schedule By Service - NASA  

Science.gov (United States)

MSC PATRAN & NASTRAN Licenses Contract (Transitioned Jun 2006). COTR Training Recompetition (Awarded Jan 2007). Closeout Services Contract ...

100

Lapses following Alcohol Treatment: Modeling the Falls From the Wagon*  

UK PubMed Central (United Kingdom)

ObjectiveThis study investigated transitions between drinking and nondrinking during the first 12 months following treatment and whether transitions in posttreatment...Full Text Available

2008-07-01

101

FFTF & Advance Reactors Transition Program Resource Loaded Schedule  

Energy Technology Data Exchange (ETDEWEB)

This document is the annual update of the FFTF and Advanced Reactors Transition Program Resource Loaded Schedule for FY 2002 using current project direction and authorized funding levels

2001-10-25

102

Excitonic transitions in InGaP/InAlGaP strained quantum wells  

Science.gov (United States)

Excitonic transitions in metalorganic vapor phase epitaxially grown In[sub [ital x

1993-08-30

103

 

Wastenet

Pages 184-197: Understanding Personal Change in a Women’s Faith-Based Transitional Center/title link ...titleUnderstanding Personal Change in a Women’s Faith-Based Transitional Center/dc:title

104

Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization  

Energy Technology Data Exchange (ETDEWEB)

When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl{sub 2}, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the {epsilon}-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and {alpha}-helix form ...

2007-10-15

105

Formation and stabilization of anionic metal complexes in concentrated aqueous quaternary ammonium salt solutions  

Energy Technology Data Exchange (ETDEWEB)

Anionic complexes of transition metals were stabilized in aqueous solutions containing high concentrations of various short-chain quaternary ammonium salts. Compounds with longer paraffin chains were effective in much less concentrated solution. Complex ions were detected spectrophotometrically. FeCl/sub 4//sup -/, which is usually formed in concentrated HCl, was the predominant Fe(III) complex in 30 m choline chloride containing only 0.12 M HCl. A yellow transitory Tc(VII) chloro-addition intermediate, formed in the reduction of TcO/sub 4//sup -/ by concentrated HCl, was stabilized when the solution also contained 25 m choline chloride. Its spectrum, as well as the isolation of an already known Tc(VII) bipyridyl complex, is reported. Concentrated organic electrolytes also stabilized Tc(V) oxide halides against disproportionation and Tc(IV) hexahalides against hydrolysis. Halochromates of Cr(VI) were ...

1985-02-04

106

A15 superconductors through direct solid-state precipitation: V/sub 3/Ga and Nb/sub 3/Al  

Energy Technology Data Exchange (ETDEWEB)

A solid-state precipitation process was used to prepare superconducting tapes containing an A15 phase, V/sub 3/Ga or Nb/sub 3/Al, in a ductile niobium or vanadium containing BCC matrix. Ingots weighing as large as 30 to 50 gms of V-(14 approx. 19 at. %) Ga and Nb-(13 approx. 22 at. %) Al were prepared by arc-melting, homogenized, quenched, warm-rolled over 99% into tape, and aged at temperatures in the range 600/sup 0/C to 1000/sup 0/C to precipitate the superconducting A15 phase. The features demonstrated by the process are very attractive for practical applications. In the V-Ga system, transmission electron microscopy (TEM) studies revealed the A15 precipitates in an elongated form. However, for the Nb-Al samples, deformed and aged at 750/sup 0/C, TEM studies revealed A15 precipitation in fine equi-axed particles which formed as a semi-continuous network over sub-grain boundaries formed by the recovery of ...

1980-09-01

107

Direct measurement of the alpha-epsilon transition stress and kinetics for shocked iron  

Energy Technology Data Exchange (ETDEWEB)

Iron undergoes a polymorphic phase transformation from alpha phase (bcc) to the epsilon phase (hcp) when compressed to stresses exceeding 13 CPa. Bccause the epsilon phase is denser than the alpha phase, a single shock wave is unstable and breaks up into an elastic wave, a plastic wave, and a phase transition wave. Examination of this structured wave coupled with various phase transformation models has been used to indirectly examine the transition kinetics. Recently, multimillion atom simulations (molecular dynamics) have been used to examine the shock-induced transition in single crystal iron illustrating an orientation dependence of the transition stress, mechanisms, and kinetics. The objective of the current work was to perform plate impact experiments to examine the shock-response of polycrystalline and single crystal iron with nanosecond resolution for impact stresses spanning the {alpha} - ...

2009-01-01

108

"Hyperfine Splitting, Isotope Shift, and Level Energy of the 3S States of Li-6, Li-7."  

Energy Technology Data Exchange (ETDEWEB)

High-precision laser spectroscopy on lithium isotopes is of fundamental interest, experimentally as well as theoretically. The lithium atom has long served as a test system for the calculation of various atomic properties in few-electron atoms and significant advances have been made in the last decade[1-3]. Recently, calculations of transition energies for the 22S1/2 -> 32S1/2 and the 22S1/2 -> 22P1/2, 3/2 transitions and of the mass-dependant isotope shift (IS) in these transitions have been reported with a relative accuracy of better than 1 X 10-7 and 5 x 10-6, respectively[4, 5]. These calculations are the foundation for experimental efforts, currently underway at GSI Darmstadt, Germany, to determine the root-mean-square (rms) charge radius of the unstable lithium isotopes[6, 7]. The basic principle is that if all mass-dependent contributions to the IS can be calculated with sufficient accuracy, the ...

2003-07-25

109

Synthesis, structure, and spectroscopic properties of ortho-metalated platinum(II) complexes  

Energy Technology Data Exchange (ETDEWEB)

The ortho-metalated Pt(II) complexes Pt(ppy)(CO)Cl (1), Pt(ptpy)(CO)Cl (2), and Pt(ppy)(Hppy)Cl (3) (where ppy and ptpy are respectively the ortho-C-deprotonated forms of 2-phenylpyridine and 2-p-tolylpyridine and Hppy is 2-phenylpyridine) have been prepared. The CO ligand is coordinated trans to the nitrogen atom of the ortho-metalated ligand and exerts a strong trans effect resulting in a relatively long Pt-N bond [2.114(19) {angstrom}]. This structure shows both the bidentate ppy ligand and the monodentate Hppy with the nitrogens of these ligands trans to each other. The UV/vis electronic absorption spectra of 1-3 have intense bands in the near-UV region ({approximately}375 nm) which have been assigned as metal to ligand charge transfer (MLCT) transitions, and higher energy bands were assigned as ligand-centered transitions. Each complex exhibits relatively long-lived structured emissions in the solid state at ambient ...

1995-04-26

110

Electronic and geometric structure of transition-metal nanoclusters  

Energy Technology Data Exchange (ETDEWEB)

A massively-parallel ab initio computer code, which uses Gaussian bases, pseudopotentials, and the local density approximation, permits the study of transition-metal systems with literally hundreds of atoms. We present total energies and relaxed geometries for Ru, Pd, and Ag clusters with N = 55, 135, and 140 atoms; we also used the DMOL code to study 13-atom Pd and Cu clusters, with and without hydrogen. The N = 55 and 135 clusters were chosen because of simultaneous cubo-octahedral (fcc) and icosahedral (icos) sub-shell closings, and we find icos geometries are preferred. Remarkably large compressions of the central atoms are observed for the icos structures (up to 6% compared with bulk interatomic spacings), while small core compressions ({approx} 1 %) are found for the fcc geometry. In contrast, large surface compressive relaxations are found for the fcc clusters ({approx} 2-3% in average nearest neighbor spacing), while the icos surface displays small ...

1996-08-01

111

Electric-field-dependent electroreflectance spectra of visible-band-gap (InAlGa)P quantum-well structures  

Science.gov (United States)

We present results from the first studies of electric-field effects on optical transitions in visible-band-gap InGaP/InAlGaP multiple-quantum-well (MQW) structures. These structures, grown at 775 [degree]C by metalorganic vapor phase epitaxy on (100) GaAs substrates misoriented 6[degree] towards P(111)[r angle][l angle]111[r angle]A, consist of nominally undoped MQWs surrounded by doped In[sub 0.49]Al[sub 0.51]P cladding layers to form [ital p]-[ital i]-[ital n] diodes. The Stark shifts of various allowed and forbidden quantum-well transitions were observed in bias-dependent electroreflectance spectra of In[sub 0.49]Ga[sub 0.51]P/In[sub 0.49](Al[sub 0.5]Ga[sub 0.5])[sub 0.51]P MQW samples with 10-nm-thick layers. We find the magnitude of these shifts to depend on the details of the Mg doping profile, confirming the importance of Mg diffusion and unintentional background doping in these materials. Our results show that ...

1994-04-04

112

Electric-field-dependent electroreflectance spectra of visible-band-gap (InAlGa)P quantum-well structures  

International Nuclear Information System (INIS)

We present results from the first studies of electric-field effects on optical transitions in visible-band-gap InGaP/InAlGaP multiple-quantum-well (MQW) structures. These structures, grown at 775 degree C by metalorganic vapor phase epitaxy on (100) GaAs substrates misoriented 6 degree towards P(111)right-angle left-angle 111 right-angle A, consist of nominally undoped MQWs surrounded by doped In_0_._4_9Al_0_._5_1P cladding layers to form p-i-n diodes. The Stark shifts of various allowed and forbidden quantum-well transitions were observed in bias-dependent electroreflectance spectra of In_0_._4_9Ga_0_._5_1P/In_0_._4_9(Al_0_._5Ga_0_._5)_0_._5_1P MQW samples with 10-nm-thick layers. We find the magnitude of these shifts to depend on the details of the Mg doping profile, confirming the importance of Mg diffusion and unintentional background doping in these materials. Our results show that (InAlGa)P materials are promising for ...

113

Dielectric and piezoelectric properties of K0.5Na0.5NbO3-AgSbO3 lead-free ceramics  

Science.gov (United States)

Lead-free piezoelectric ceramics (1-x)K0.5Na0.5NbO3-xAgSbO3+0.75 mol % MnO2 were prepared by a conventional solid-state sintering technique, and the piezoelectric and dielectric properties of the ceramics were studied. The results of x-ray diffraction suggest that AgSbO3 diffuses into the K0.5Na0.5NbO3 lattices to form a new solid solution with a single-phase orthorhombic perovskite structure. After the addition of AgSbO3, the paraelectric cubic-ferroelectric tetragonal phase transition temperature (TC) and the ferroelectric tetragonal-ferroelectric orthorhombic phase transition temperature (TO-T) decrease, and the ceramics become ``softened,'' resulting in significant improvements in the ferroelectric and piezoelectric properties. The ceramics with x=0.03-0.10 exhibit excellent piezoelectric properties: d33=130-216 pC/N, kp=0.44-0.51, and kt=0.40-0.52. The ceramics also exhibit a good thermal stability up to high TO-T, ...

2009-08-01

114

Counter-current air-water flow in narrow rectangular channels with offset strip fins  

Energy Technology Data Exchange (ETDEWEB)

Counter-current two-phase flows of air-water in narrow rectangular channels with offset-strip fins have been experimentally investigated in a 760 mm long and 100 mm wide test section with 3.0 and 5.0 mm gap widths. The two-phase flow regime, channel-average void fractions and two-phase pressure gradients were studied. Flow regime transition occurred at lower superficial velocities of air than in the channels without fins. In the bubbly and slug flow regimes, elongated bubbles rose along the subchannel formed by fins without lateral movement. The critical void fraction for the bubbly-to-slug transition was about 0.14 for the 3 mm gap channel and 0.2 for the 5 mm gap channel, respectively. Channel-average void fractions in the channels with fins were almost the same as those in the channels without fins. Void fractions increased as the gap width increased, especially at high superficial velocity of air. The presence of fins ...

2003-03-01

115

The projector augmented wave method: A fast all-electron procedure for the ab-initio molecular dynamics  

International Nuclear Information System (INIS)

In this thesis, a new ab-initio method for molecular dynamics within the framework of density functional theory was developed and implemented. It is strongly related to the projector-augmented-wave method (PAW) by P. Bloechl, but also includes elements of a pseudocharge method proposed by M. Weinert for the full-potential linearized augmented plane wave method (FLAPW). Like the FLAPW-method, the PAW-method is an all-electron method. In the later case, the hamiltonian takes quite a simple form similar to the one obtained when using normconserving Kleinman-Bylander-type pseudopotentials or ultrasoft Vanderbilt pseudopotentials. The PAW-method allows for an efficient calculation of systems containing virtually any element of the periodic table, including those which require high numerical effort when treated using normconserving pseudopotentials (e.g. 2p-elements like oxygen or 3d-transitional metals like copper). In addition, a higher accuracy ...

116

Stabilization of high-temperature antimony oxide with molybdenum incorporation. Structure of Mo-doped Sb/sub 2/O/sub 4/ by powder neutron diffraction and extended X-ray absorption fine structure spectroscopy  

Energy Technology Data Exchange (ETDEWEB)

It has been discovered that the presence of MoO/sub 3/ lowers the ..cap alpha..-..beta.. transition in Sb/sub 2/O/sub 4/ from 935 to 850/sup 0/C with concurrent dissolution of Mo in the high-temperature (..beta..) form. The structure of Mo-doped ..beta..-Sb/sub 2/O/sub 4/ has been investigated by powder neutron diffraction, extended X-ray absorption fine structure (EXAFS) and Raman spectroscopies, and scanning-electron microscopy (SEM). Cell parameters: a = 12.0571 (12) A, b = 4.8335 (1) A, c = 5.3838 (6) A, ..beta.. = 105.579 (5)/sup 0/, monoclinic, space group C2/c, Z = 4. Combining the results of these techniques leads to the hypothesis that Mo is located interstitially within channels of electron density in the Sb/sub 2/O/sub 4/ structure with concurrent vacancy of two Sb/sup III/ atoms. There is no apparent oxygen deficiency in the resulting structure. 25 references, 6 figures, 3 tables.

1985-10-09

117

Sequence of Potentials Lying Between the U(5) and X(5) Symmetries  

CERN Document Server

Starting from the original collective Hamiltonian of Bohr and separating the beta and gamma variables as in the X(5) model of Iachello, an exactly soluble model corresponding to a harmonic oscillator potential in the beta-variable (to be called X(5)-$\\beta^2$) is constructed. Furthermore, it is proved that the potentials of the form $\\beta^{2n}$ (with n being integer) provide a ``bridge'' between this new X(5)-$\\beta^2$ model (occuring for n=1) and the X(5) model (corresponding to an infinite well potential in the beta-variable, materialized for n going to infinity. Parameter-free (up to overall scale factors) predictions for spectra and B(E2) transition rates are given for the potentials $\\beta^2$, $\\beta^4$, $\\beta^6$, $\\beta^8$, corresponding to E(4)/E(2) ratios of 2.646, 2.769, 2.824, and 2.852 respectively, compared to the E(4)/E(2) ratios of 2.000 for U(5) and 2.904 for X(5). Hints about nuclei showing this behaviour, as well as ...

2004-01-01

118

Quinary metallic glass alloys  

Energy Technology Data Exchange (ETDEWEB)

At least quinary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10.sup.3 K/s. Such alloys comprise zirconium and/or hafnium in the range of 45 to 65 atomic percent, titanium and/or niobium in the range of 4 to 7.5 atomic percent, and aluminum and/or zinc in the range of 5 to 15 atomic percent. The balance of the alloy compositions comprise copper, iron, and cobalt and/or nickel. The composition is constrained such that the atomic percentage of iron is less than 10 percent. Further, the ratio of copper to nickel and/or cobalt is in the range of from 1:2 to 2:1. The alloy composition formula is: (Zr,Hf).sub.a (Al,Zn).sub.b (Ti,Nb).sub.c (Cu.sub.x Fe.sub.y (Ni,Co).sub.z).sub.d wherein the constraints upon the formula are: a ranges from 45 to 65 atomic percent, b ranges from 5 to 15 atomic percent, c ranges from 4 to 7.5 atomic percent, d comprises the balance, d.multidot.y is less than 10 atomic ...

1998-01-01

119

Promising electrolyte materials for the coming lithium secondary batteries. Lithium ion conductive inorganic solid electrolytes; Jisedai lithium niji denchiyo denkaishitsu. Muki kotai denkaishitsu  

Energy Technology Data Exchange (ETDEWEB)

This paper describes inorganic solid electrolytes from a viewpoint of electrolytes for lithium batteries. Lithium ion conductive inorganic solid electrolytes are largely divided into crystalline and amorphous substances. Crystalline substances are known as LiI and Li3N, and also oxygen acid salt. However, when considering application to a battery, its large grain boundary resistance and electrochemical instability would be a problem. Lithium ion conductive amorphous solid electrolytes are divided into an oxide system and a sulfide system. Since most of them do not contain transition metal elements, they are stable against electrochemical reduction, and ions move isotropically in electrolyte. Therefore, ion conduction paths across the grain boundaries may be connected more easily, forming an electrolyte with low grain boundary resistance. As a result of the efforts of the authors in searching new additives substituting LiI, it was found that ...

1997-11-05

120

Piezoelectric Properties of (1-x)(Na0.5K0.5)NbO3-xAgSbO3 Lead-Free Ceramics  

British Library Electronic Table of Contents (United Kingdom)

(1-x)(Na0.5K0.5)NbO3-xAgSbO3 lead-free piezoelectric ceramics were prepared by normal sintering. The effects of the AgSbO3 on the phase structure and piezoelectric properties of the ceramics were systematically studied. These results show that the AgSbO3-modified (K0.50Na0.50)NbO3 lead-free piezoelectric ceramics form stable solution with orthorhombic structure, and the Curie temperature and the polymorphic phase transition of the ceramics decreased with increasing AgSbO3. The result shows that the piezoelectric properties of the ceramics strongly depend on the AgSbO3. The ceramics with x=0.05 possess optimum properties (d33=192 pC/N, kp=43%, Tc=348degreeC, To-t=145degreeC, ?r632, and tan d3.5%). These results indicate that the ceramic is a promising candidate material for lead-free piezoe...

2009-01-01

121

Photoluminescence properties and local electronic structures of rare earth-activated Sr3AlO4F  

British Library Electronic Table of Contents (United Kingdom)

Photoluminescence properties and local electronic structures of rare earth (Eu^3^+ and Ce^3^+) activated Sr3AlO4F have been studied. X-ray powder diffraction data indicated that the activator ions of Eu^3^+ and Ce^3^+ can be incorporated into the Sr3AlO4F lattice and formed limited solid solutions of Sr3-2xLnxNaxAlO4F (Ln=Eu, Ce) with Na^+ as a charge compensator ion. The local structure around Sr sites was initially explored using Eu-activated Sr3AlO4F as a structural probe. Sr3AlO4F:Eu^3^+ exhibits orange-red emission ranging from 520 to 740nm with a maximum peak at about 619nm mainly originating from the ^5D0->^7FJ (J=0, 1, 2, 3, 4) transitions, indicating that Eu exists mainly in the trivalent state due to a strong oxidative lattice in Sr3AlO4F. Sr3AlO4F:Ce^3^+ shows an unusual long-wa...

2010-01-01

122

Orion's Bar: Physical Conditions across the Definitive H+ / H0 / H2 Interface  

CERN Document Server

Previous work has shown the Orion Bar to be an interface between ionized and molecular gas, viewed roughly edge on, which is excited by the light from the Trapezium cluster. Much of the emission from any star-forming region will originate from such interfaces, so the Bar serves as a foundation test of any emission model. Here we combine X-ray, optical, IR and radio data sets to derive emission spectra along the transition from H+ to H0 to H2 regions. We then reproduce the spectra of these layers with a simulation that simultaneously accounts for the detailed microphysics of the gas, the grains, and molecules, especially H2 and CO. The magnetic field, observed to be the dominant pressure in another region of the Orion Nebula, is treated as a free parameter, along with the density of cosmic rays. Our model successfully accounts for the optical, IR and radio observations across the Bar by including a significant magnetic pressure and also heating ...

2008-01-01

123

Optical and electronic properties of Ag nanodots on Si(111)  

International Nuclear Information System (INIS)

Reflectance anisotropy spectroscopy (RAS) has been used, together with scanning tunnelling spectroscopy (STS), to investigate the optical and electronic properties of nanodots formed by depositing Ag on the Si(111)-3 x 1-Ag surface. One-dimensional (1D) arrays of nanodots were grown on a single-domain (3 x 1)-Ag surface and the anisotropic optical response in the 0.5-5 eV range measured by RAS. Aligned, elongated Ag islands were also grown on this surface to compare their properties with those of the nanodots. STS of the Ag islands showed distinct metallic behaviour, whereas the nanodots revealed a bandgap of #approx#0.6 eV, indicating that the surface of the dots has a non-metallic character, similar to that of the Si(111)-3 x 1-Ag surface. RAS also showed substantial differences between the structures, with a large infrared anisotropy for the metallic Ag islands consistent with anisotropic Drude-like intraband transitions, whereas the ...

2006-08-02

124

Observing Evolution in the Supergranular Length Scale During Periods of Low Solar Activity  

CERN Document Server

We present the initial results of an observational study into the variation of the dominant length-scale of quiet solar emission: supergranulation. This length-scale reflects the radiative energy in the plasma of the upper solar chromosphere and transition region at the magnetic network boundaries forming as a result of the relentless interaction of magnetic fields and convective motions of the Sun's interior. We demonstrate that a net difference of ~0.5Mm in the supergranular emission length-scale occurs when comparing observations cycle 22/23 and cycle 23/24 minima. This variation in scale is reproduced in the datasets of multiple space- and ground-based instruments and using different diagnostic measures. By means of extension, we consider the variation of the supergranular length-scale over multiple solar minima by analyzing a subset of the Mt Wilson Solar Observatory (MWO) Ca II K image record. The observations and analysis presented ...

2011-01-01

125

New short-range electromagnetic current in the deuteron  

International Nuclear Information System (INIS)

A new model for short-range isoscalar current in the deuteron and NN system is developed and tested on a variety of isoscalar magnetic observables such as the deuteron magnetic moment, magnetic form factor, and the circular polarization of photons at n"#->#p radiative capture at thermal neutron energies. The model for electromagnetic two-nucleon current proposed in the paper is based on generation of an intermediate dibaryon in the short-range NN interaction. This intermediate dibaryon, in turn, is treated within the new model for intermediate and short-range NN interaction recently proposed by the present authors. The transition current model developed here satisfies the current conservation relation by the construction. Our calculations have demonstrated that the new current model, using only one parameter (with a clear physical meaning), is able to describe, in very good agreement with the experimental data, three basic deuteron ...

2007-02-01

126

Neutron scattering studies of mixed-valence semiconductors  

Energy Technology Data Exchange (ETDEWEB)

Neutron scattering experiments on the mixed-valence (MV) compounds SmB{sub 6} are reported. The inelastic magnetic response of SmB{sub 6} at T = 2 K, measured on a double-isotope single crystal,displays a strongly damped peak at 35 meV corresponding to the inter multiplet transition of Sm{sup 2+}. At lower energies ( h.{omega} {approx_equal} 14 meV), a narrow magnetic excitation is observed, with remarkable scattering-vector and temperature dependences of its intensity. This novel feature is discussed in terms of recent theoretical works describing the formation of an anisotropic local bound state in semiconducting MV materials. If the average samarium valence is decreased by substituting La for Sm, a peak is found to appear at high energies. The elastic magnetic form factor of SmB{sub 6} was determined using polarised neutrons and no significant difference is observed in its Q-dependence with respect to that of pure divalent samarium. This ...

1994-12-31

127

Modeling and Analysis of K-Tier Downlink Heterogeneous Cellular Networks  

CERN Document Server

Cellular networks are in a major transition from a carefully planned set of large tower-mounted base-stations (BSs) to an irregular deployment of heterogeneous infrastructure elements that often additionally includes micro, pico, and femtocells, as well as distributed antennas. In this paper, we develop a tractable, flexible, and accurate model for a downlink heterogeneous cellular network (HCN) consisting of K tiers of randomly located BSs, where each tier may differ in terms of average transmit power, supported data rate and BS density. Assuming a mobile user connects to the strongest candidate BS, the resulting Signal-to-Interference-plus-Noise-Ratio (SINR) is greater than 1 when in coverage, Rayleigh fading, we derive an expression for the probability of coverage (equivalently outage) over the entire network under both open and closed access, which assumes a strikingly simple closed-form in the high SINR regime and is accurate down to -4 dB ...

2011-01-01

128

Microstructural characterization of Ti-6Al-4V metal chips by focused ion beam (FIB) and transmission electron microscopy (TEM)  

Energy Technology Data Exchange (ETDEWEB)

The microstructure of the secondary deformation zone (SDZ) near the cutting surface in metal chips of Ti-6Al-4V formed during machining was investigated using focused ion beam (FIB) specimen preparation and transmission electron microscopy (TEM) imaging. Use of the FIB allowed precise extraction of the specimen across this region to reveal its inhomogeneous microstructure resulting from the non-uniform distribution of strain, strain rate, and temperature generated during the cutting process. Initial imaging from conventional TEM foil preparation revealed microstructures ranging from heavily textured to regions of fine grains. Using FIB preparation, the transverse microstructure could be interpreted as fine grains near the cutting surface which transitioned to coarse grains toward the free surface. At the cutting surface a 10 nm thick recrystallized layer was observed capping a 20 nm thick amorphous layer.

2011-01-01

129

Local Group Dwarf Galaxies: Nature And Nurture  

CERN Document Server

We investigate the formation and evolution of dwarf galaxies in a high resolution, hydrodynamical cosmological simulation of a Milky Way sized halo and its environment. Our simulation includes gas cooling, star formation, supernova feedback, metal enrichment and UV heating. In total, 90 satellites and more than 400 isolated dwarf galaxies are formed in the simulation, allowing a systematic study of the internal and environmental processes that determine their evolution. We find that 95% of satellite galaxies are gas-free at z=0, and identify three mechanisms for gas loss: supernova feedback, tidal stripping, and photo-evaporation due to re-ionization. Gas-rich satellite galaxies are only found with total masses above ~ 5x10^9 solar masses. In contrast, for isolated dwarf galaxies, a total mass of ~ 10^9 solar masses constitutes a sharp transition; less massive galaxies are predominantly gas-free at z=0, more massive, isolated dwarf galaxies are ...

2011-01-01

130

Hydrogen trapping by yttrium in low temperature lithium  

Energy Technology Data Exchange (ETDEWEB)

A test to determine the lithium compatibility and impurity gettering capabilities of various materials including yttrium was performed in Beryllium-7 Experimental Lithium (7BELL) at 270/sup 0/C. Yttrium coupons were exposed in liquid lithium for a total of 3,718 hours. X-ray diffraction and bulk chemical analysis data indicated that yttrium absorbs hydrogen from liquid lithium at 270/sup 0/C and transforms to yttrium dihydride (YH/sub 2/). The transformation of yttrium to YH/sub 2/ resulted in embrittlement of the coupons and subsequent fragmentation to small pieces. Additional analysis, based on the equilibrium hydrogen pressures for the transition of yttrium to YH/sub 2/, and Sievert's relationship for hydrogen in equilibrium with hydrogen in lithium, indicates that the temperature of yttrium cannot exceed 280/sup 0/C to control the hydrogen concentration in lithium at below 1 wt ppm. It is concluded in general that yttrium in sponge ...

1984-05-01

131

Formation of A-15 filaments in Cu-base alloys  

International Nuclear Information System (INIS)

Brittleness and poor low-temperature thermal conductivity of A-15 compounds remain the major obstacles preventing the effective use of these superconductors in large-scale engineering applications. In order to circumvent these difficulties, a new type of ductile superconducting filamentary alloy has been developed recently by a simple metallurgical process which consists of melting the constituent elements and subsequent cold working and appropriate heat treatment. These superconducting materials are essentially Cu-base alloys containing a few percent of A-15 phase such as Nb_3Sn or V_3Ga which is in the form of fine filaments embedded in the Cu matrix. The emphasis of this work is on the formation of the A-15 phase in the Cu-base alloys and its correlation with superconducting properties such as transition temperature and critical current density. The formation of Nb_3Sn, Nb_3Al, V_3Si, and V_3Ga will serve as examples to illustrate the ...

132

Experiments on the formation of the A 15-compounds Nb-Sn and Nb-Ge by ion implantation  

International Nuclear Information System (INIS)

Nb_3Sn films (Tsub(c)=17.8 K) were obtained by implantation of Sn"+ ions into Nb films (1500 A thick) after subsequent annealing. The annealing temperature required for the formation of the A15 phase in the implanted films was about 100 K higher than for Nb-Sn sandwich films evaporated at 300 K. The influence of the Sn concentration and of the annealing temperature was studied by measuring the sample resistance. The Nb-Sn compounds formed during the annealing process were analysed by measurements of the Moessbauer-effect of "1"1"9Sn. The implantation method was also used to produce Nb-Ge films with a ratio Ge/Nb approximately 1/3. The Ge-concentration and the temperature of the Nb-target (300-1070 K) were varied. These variations as well as subsequent annealing at 600-850"0C did not lead to superconducting transition temperatures above 8 K. (Auth.).

133

Evaluating Systematic Dependencies of Type Ia Supernovae: The Influence of Progenitor Ne22 Content on Dynamics  

CERN Document Server

We present a theoretical framework for formal study of systematic effects in Supernovae Type Ia (SN Ia) that utilizes 2-d simulations to implement a form of the deflagration-detonation transition (DDT) explosion scenario. The framework is developed from a randomized initial condition that leads to a sample of simulated SN Ia whose Ni56 masses have a similar average and range to those observed, and have many other modestly realistic features such as the velocity extent of intermediate mass elements. The intended purpose is to enable statistically well-defined studies of both physical and theoretical parameters of the SN Ia explosion simulation. We present here a thorough description of the outcome of the SN Ia explosions produced by our current simulations. A first application of this framework is utilized to study the dependence of the SN Ia on the Ne22 content, which is known to be directly influenced by the progenitor stellar population's ...

2009-01-01

134

Crystalline beam ground state  

Energy Technology Data Exchange (ETDEWEB)

In order to employ molecular dynamics (MD) methods, commonly used in condensed matter physics, we have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. We include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations using MD methods has been performed to obtain the equilibrium crystalline beam structure. The effect of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time dependent. The ground state is a zero entropy state, despite the time-dependent, periodic variation of the ...

1993-06-11

135

Competition of ferromagnetism and superconductivity in Sc3InB  

Science.gov (United States)

We present results of electronic structure calculations for the intermetallic perovskite Sc3InB with the full-potential KKR-LDA method. Sc3InB is a very promising candidate for a new superconductor (related to 8 K MgCNi3) and can be regarded as a boron-inserted cubic Sc3In, which is a high-pressure allotropic form of the hexagonal weak ferromagnet Sc3In. We predict that cubic Sc3In can also be magnetic, whereas Sc3InB having large DOS in the vicinity of E F exhibits non-magnetic ground state. Estimation of the electron-phonon coupling for Sc3InB gives 1. Furthermore, the effect of vacancies in Sc3InB1-x and antisite disorder in Sc3(In-B) on critical parameters is also discussed using the KKR-CPA method. All theoretical results support the possibility of the superconductivity onset in Sc3InB. Preliminary experimental measurements established the transition temperature close to 4.5 K, with a very abrupt change in susceptibility and a correlated ...

2006-01-01

136

Aluminum-containing intergranular phases in hot-pressed silicon carbide  

Energy Technology Data Exchange (ETDEWEB)

Aluminum-containing intergranular phases, forming intergranular films and secondary phase particles at triple-junctions in SiC hot-pressed with aluminum, boron, and carbon additions, were studied by transmission electron microscopy. Statistical high-resolution electron microscopy study of intergranular films indicated that a large fraction of the vitreous intergranular films in the s-hot-pressed SiC crystallized during postannealing in argon above 1000 C. However, brief heating to 1900 C indeed re-melted 25 percent of the crystallized intergranular films. The structural transitions were reflected in the statistical width distributions of the amorphous grain boundary layers. At triple-junctions, Al2O3, Al2OC-SiC solid solution, and mullite phases were newly identified. These phases,together with others reported before are represented in a quaternary phase diagram for 1900 C. It is proposed that a SiC-Al2OC liquid domain is to be included in this ...

2003-01-12

137

A-15 compounds and their amorphous counterparts  

International Nuclear Information System (INIS)

The A-15 compounds are known to favor the occurrence of high temperature superconductivity (transition temperature T/sub c/ > 15K). The origin of superconductivity in these metals is a subject of much controversy and importance. A useful approach to this problem is to study comparatively the superconducting and normal-state properties of the A-15 superconductors and their amorphous counterparts. Efforts along these lines have yielded some insight into the mechanisms responsible for high temperature superconductivity. It is interesting to note that most high-T/sub c/ A-15 compounds contain one glass-forming element such as Ge, Si or Al and are thus conducive to the formation of a non-crystalline phase. The amorphous (or higher disordered) state of the A-15 compounds can be achieved, for example, by one of the following techniques: (1) sputtering or co-evaporation onto substrates held at relatively low temperatures; (2) particle irradiation; ...

139

Transition probability in "1"7"7Ta  

International Nuclear Information System (INIS)

... energy levels intermediate mass nuclei isotopes nuclei odd-even nuclei

140

The conversion spectrum of Sr"8"8  

International Nuclear Information System (INIS)

... beta spectrometers decay energy-level transitions k conversion l conversion

141

Precise calculation of transition frequencies of hydrogen and deuterium based on a least-squares analysis  

CERN Document Server

We combine a limited number of accurately measured transition frequencies in hydrogen and deuterium, recent quantum electrodynamics (QED) calculations, and, as an essential additional ingredient, a generalized least-squares analysis, to obtain precise and optimal predictions for hydrogen and deuterium transition frequencies. Some of the predicted transition frequencies have relative uncertainties more than an order of magnitude smaller than that of the g-factor of the electron, which was previously the most accurate prediction of QED.

2005-01-01

143

Molecular model for de Vries type smectic A - smectic C phase transition in liquid crystals  

CERN Document Server

We develop a theory of Smectic A - Smectic C phase transition with anomalously weak smectic layer contraction. We construct a phenomenological description of this transition by generalizing the Chen-Lubensky model. Using a mean-field molecular model, we demonstrate that a relatively simple interaction potential suffices to describe the transition. The theoretical results are in excellent agreement with experimental data.

2007-01-01

144

Magnetic phase transition in UPd_2Si_2  

International Nuclear Information System (INIS)

... fields magnetic moments neel temperature neutron diffraction order-disorder

145

Effect of the electron-electron coupling parameters on the superconducting transition temperature in the compounds with the A-15 structure  

International Nuclear Information System (INIS)

The electron structure of the A-15 compounds is studied by accounting for the Hubbard energy as the highest energy parameter. The conditions for the Cooper instability origination are obtained. The superconducting transition temperature dependence on the degree of filling the d- and p-shells of the transition and nontransition elements is determined. The relationship between the transition temperature and the energy jumpover along the chains, which allows comparison with the experiment, is established. Qualitative explanation of the Mattias empiric rules is presented

2000-09-01

148

Influence of the micro-addition of Mo on glass forming ability and corrosion resistance of Cu-based bulk metallic glasses  

International Nuclear Information System (INIS)

(Cu_4_7Zr_1_1Ti_3_4Ni_8)_1_0_0_-_xMo _x bulk metallic glasses (BMGs) with x = 0, 1 and 2 at.% and a bulk metallic glass matrix composite with x = 5 at.% were successfully prepared by water-cooled copper mold casting. The effect of the addition of a small amount of Mo on the glass forming ability (GFA), thermal properties of the base alloy (i.e. x = 0) were investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and differential thermal analyzer (DTA). It is found that the addition of appropriate amount of Mo can enhance the GFA of the Cu-based BMG, as indicated by the increase in the reduced glass transition temperature T _r_g (=T _g/T _l) and the parameter #gamma# (=T _x/(T _g + T _l)) with the increase of Mo. On the other hand, the corrosion resistance of the Cu-based BMGs with different Mo contents was examined by electrochemical polarization and weight loss measurement in 1 mol/L H_2SO_4 and 1 mol/L NaOH solutions, ...

2006-05-05

149

DISSIPATION AND EXTRA LIGHT IN GALACTIC NUCLEI. III. 'CORE' ELLIPTICALS AND 'MISSING' LIGHT  

International Nuclear Information System (INIS)

We investigate how 'extra' or 'excess' central light in the surface brightness profiles of cusp or power-law elliptical galaxies relates to the profiles of ellipticals with cores. The envelopes of cusp ellipticals are established by violent relaxation in mergers acting on stars present in gas-rich progenitor disks, while their centers are structured by the relics of dissipational, compact starbursts. Ellipticals with cores are formed by the subsequent merging of the now gas-poor cusp ellipticals, with the fossil starburst components combining to preserve a dense, compact component in these galaxies as well (although mixing of stars smooths the transition from the outer to inner components in the profiles). By comparing extensive hydrodynamical simulations to observed profiles spanning a broad mass range, we show how to observationally isolate and characterize the relic starburst component in core ellipticals. Our method recovers the younger ...

2009-04-01

150

Valence transition and magnetic ordering in Sn doped EuPd/sub 2/Si/sub 2/  

Energy Technology Data Exchange (ETDEWEB)

The sharp, temperature induced, continuous valence transition in EuPd/sub 2/Si/sub 2/ is drastically changed by doping with Sn at the Si site up to 5 at.%. Only a first order valence transition occurs for a 3% Sn doped sample and the 2/sup +/ component which survives the valence transition orders magnetically at 4.2 K. No valence transition at all occurs for a 5% Sn doped sample right up to 1.9 K and magnetic ordering sets in around 30 K.

1983-12-01

151

Superconductivity of neutron irradiated Mo_3Os  

International Nuclear Information System (INIS)

The effect of high energy neutron irradiation (E > 1 MeV) on the superconducting transition temperature, Tsub(c), of the A-15 compound Mo_3Os is reported. Tsub(c) was found to decrease with increasing neutron dose, but at a rate considerably less than observed in other A-15 compounds composed of non-transition metals. The results lend support to the idea that the effect of ordering on Tsub(c) is smaller for A-15 compounds composed only of transition metals than those composed of transition and non-transition metals. (author).

152

E2 transition densities and proton shell structure in /sup 88/Sr, /sup 89/Y, and /sup 90/Zr  

Energy Technology Data Exchange (ETDEWEB)

Electron scattering data have been used to obtain transition charge densities for the low-lying E2 transitions in /sup 88/Sr, /sup 89/Y, and /sup 90/Zr. These charge densities show a characteristic shape indicative of their microscopic constituency, modified by core-polarization effects. A good description of transitions in the even-even nuclei is obtained by using the measured single-particle transitions in /sup 89/Y as effective densities. .ID LV2086 .PG 19 22

1983-01-03

153

Controlling transit-bus emissions and improving management  

Energy Technology Data Exchange (ETDEWEB)

The 8 papers in the report deal with the following areas: Introduction to diesel particulate emissions, alternative fuels, and the transit industry; Technical problems and policy issues associated with the 1991 bus emissions standards; Reducing transit bus emissions: comparative costs and benefits of methanol, particulate traps, and fuel modification; Effects of applying emissions averaging, trading, and banking to transit buses; Strategic review of heavy-duty engine emission regulations and alternate fuels; Meeting bus emissions standards--a perspective; Economic evaluation of bus maintenance contracting; Objectives for a transit-bus-fleet management data, information, and knowledge exchange.

1988-01-01

154

Refining the Magnetic Forming Capability.  

Science.gov (United States)

... Title : Refining the Magnetic Forming Capability. ... Abstract : The purpose of this project was to refine the in-house magnetic forming capability. ...

1972-04-01

155

CAPACITOR DISCHARGE METAL FORMING  

Science.gov (United States)

... Report Date : JUL 1961. Pagination or Media Count : 39. Abstract : Open-ende Terms: Electrohydraulic forming, Magnetic forming. ...

1961-07-01

156

An investigation of the decoupling effects in a magnetic forming beryllium coil assembly.  

Science.gov (United States)

Decoupling force exerted by magnetic forming Be coil assembly on metallic plate during forming

1968-01-01

157

/22k : - NASA Technical Reports Server  

Science.gov (United States)

in pulse applications such as magnetic forming. ... In magnetic-forming electric circuitry, the ..... Aspects of Electrohydraulic land Magnetic Forming. ...

158

Wisconsinan-Holocene seismic stratigraphy of the Keathley Canyon Area and vicinity, northwestern Gulf of Mexico  

Science.gov (United States)

The lower continental slope of the northwestern Gulf of Mexico is characterized by a hummocky topography with shallow salt masses interspersed by numerous salt-withdrawal basins containing thick Plio-Pleistocene and older sediments. Analysis of over 7500 km of multichannel seismic reflection data from the Keathley Canyon Area and vicinity defined the Wisconsinan-Holocene sequence and its seismic facies. In interbasinal areas and in the southern part of the study area where salt is shallow, the Wisconsinan-Holocene sequence consists mainly of low-amplitude (LA) facies underlain by strong basal-reflection (SBR) facies. The LA facies occasionally show subtle onlaps against SBR facies and grade upward into a draping pattern. Onlapping LA facies are interpreted to be a lowstand systems tract deposited by widespread low-energy turbidity currents. Draping LA facies at the top may consist of hemipelagic or pelagic sediments. The SBR facies are interpreted to consist of condensed sections ...

1991-03-01

159

THE EFFECT OF INTERSTITIAL N ON GRAIN BOUNDARY COHESIVE STRENGTH IN Fe  

Energy Technology Data Exchange (ETDEWEB)

Increased nitrogen levels have been correlated with decreased ductility and elevated ductile-to-brittle transition temperature in pressure vessel steels [1]. However, the exact role played by nitrogen in the embrittlement of steels remains unclear. Miller and Burke have reported atom probe ion microscopy findings from neutron-irradiated low-alloy pressure vessel steel showing the presence of a 1 to 2 ruonolayer thick film of Mo, N, and C at prior austenitic grain boundaries (GB's) [2], suggesting a role for nitrogen as an intergranular embrittler. It is of interest for the development of mitigation strategies whether nitrogen must combine with other impurities to form nitride precipitates in order to exert an embrittling effect. Briant et al [1] have associated the embrittling effect of N in steels exclusively with intergranular nitride formation. This association suggests that high nitrogen levels may be acceptable if nitride ...

2003-09-22

160

Recombination mechanisms at window/emitter interface in InP and other III-V semiconductor based solar cells  

Energy Technology Data Exchange (ETDEWEB)

The effect of various window layers for InP solar cells are studied. Window materials that have type 1 and type 2 alignment in the window/emitter interface are compared. All window materials that form a type 2 alignment with InP, such as Al{sub 0.20}In{sub 0.80}P, Ga{sub 0.20}In{sub 0.80}P, Al{sub 0.55}In{sub 0.45}As and Al{sub 0.60}In{sub 0.40}P, cause a high interface recombination velocity, which deteriorates the carrier collection. This recombination takes place due to the spatially indirect quantum well transition between the triangular quantum wells formed in the interface. ZnSe as a window layer material with type 1 alignment does not have this problem, but still decreased response in the short wavelength region is observed due to misfit dislocation induced trap sites. Future prospects for the window layer development for InP are discussed. The discussion is extended also to other III-V semiconductor based solar cell ...

1994-12-31

161

Optical absorptance and thermomodulation studies of several A-15 compounds  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this work was to investigate the optical properties of several high T/sub c/ compounds in the form of sputtered films. The measurements are used toward this end: optical absorptance (using a calorimetric technique near 4.2K), which yields (after Kramers-Kronig analysis) the complex dielectric function, and thermoreflectance (which measures the change in reflectance in the optical range when a 1 to 10/sup 0/K temperature wave is applied), performed at two ambient temperatures (80 and 300/sup 0/K), yielding the differential dielectric function. The sputtered films included Nb/sub 3/Ge, Nb/sub 3/Al, V/sub 3/Ga and Nb/sub 3/Ir. It is noted that Nb/sub 3/Ir is not a high T/sub c/ superconductor. The thermoreflectance on the bulk samples V/sub 3/Si, V/sub 3/Ge and single crystal Cr/sub 3/Si were not performed because the samples were not in the form of thin films. The thermomodulation studies are correlated with the absorptance ...

1983-06-01

162

Optical absorptance and thermomodulation studies of several A-15 compounds  

International Nuclear Information System (INIS)

The purpose of this work was to investigate the optical properties of several high T/sub c/ compounds in the form of sputtered films. The measurements are used toward this end: optical absorptance (using a calorimetric technique near 4.2K), which yields (after Kramers-Kronig analysis) the complex dielectric function, and thermoreflectance (which measures the change in reflectance in the optical range when a 1 to 10_0K temperature wave is applied), performed at two ambient temperatures (80 and 300_0K), yielding the differential dielectric function. The sputtered films included Nb"3Ge, Nb"3Al, V"3Ga and Nb"3Ir. It is noted that Nb"3Ir is not a high T/sub c/ superconductor. The thermoreflectance on the bulk samples V"3Si, V"3Ge and single crystal Cr"3Si were not performed because the samples were not in the form of thin films. The thermomodulation studies are correlated with the absorptance measurements in comparison to band structure ...

163

Large orbital magnetic moment and its quenching in the itinerant uranium intermetallic compounds UTGa_5 (T=Ni, Pd, Pt)  

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 the magnetic form ...

2003-12-01

164

Formation and capacitance of Nb{sub 2}O{sub 5} thin film on aluminum foil by sol-gel process; Zoru-geru ho niyoru aruminiumuhakujo eno Nb{sub 2}O{sub 5} hakumaku no sakusei to yoryotokusei  

Energy Technology Data Exchange (ETDEWEB)

Nb{sub 2}O{sub 5} thin films were formed on aluminum foils by a sol-gel process in order to increase the capacitance of the aluminum foils which are used as aluminum electrolytic capacitors. Investigations focussed on the preparation and characterization of the coating solution, the formation of Nb{sub 2}O{sub 5} thin films on aluminum foils, and the heat treatment and anodization of the films. The phase transition and electrical properties, such as capacitance, leakage current, and withstand voltage of the Nb{sub 2}O{sub 5} thin films were also measured. The Nb{sub 2}O{sub 5} thin films annealed at temperatures below 550 degree C were found to be amorphous, but they were crystallized to the orthorhombic phase by annealing at temperatures higher than 580 degree C. The capacitance of the coated samples increased with an increase in the thickness of the formed Nb{sub 2}O{sub 5} thin films, but an increase in leakage current ...

1999-12-01

165

Base-level cycles and episodic coal accumulation - case study of Dongsheng coalfield in Ordos basin  

Energy Technology Data Exchange (ETDEWEB)

The advantage of high-resolution sequence stratigraphy, which takes base-levels as reference, is that it can be applied to continental depositional basins controlled by multiple factors and can effectively improve the accuracy and resolution of sequential stratigraphic analysis. Moreover, the principles of base-level cycles are also suitable for analyzing sequential stratigraphy in continental coal-bearing basins because of their accuracy in forecasting distribution of coal measures. By taking the Dongsheng coalfield in the Ordos basin as an example, the extensive application of base-level cycles in exploration and exploitation of coal is analyzed. The result shows that the Yan'an formation in the Dongsheng area is a long-term base-level cycle which is bordered by nonconformities and made up of five mid-term cycles and 13 short-term cycles. The long-term cycle and the mid-term cycles are obvious in comparison with a transverse profile. The episodic coal accumulation in the ...

2006-12-15

166

Steam turbines. Dampfturbinen  

Energy Technology Data Exchange (ETDEWEB)

Published in summary form only.

1992-04-01

167

PLASMA JET WELDING, COATING, AND CUTTING: AN ...  

Science.gov (United States)

... 31. New electric forming methods offer potentials for light metals; magnetic forming and plasma forming. ... 3, 25 Magnetic Forming ..... ...

1963-02-01

168

Phase transition in a simple plasma model  

CERN Document Server

A phase transition of gas-liquid type with an upper critical point is examined which arises in a model of charges of one sign on compensating background (OCP). The phase transition parameters are dependent on the detailed assumptions about the compressibility of the background, but the occurrence of this transition is independent on the background equation of state. In the electron-gas model ('jellium'), this transition appears to rule out Wigner crystallization. A variational principle in statistical mechanics is used to derive so-called Double-OCP model for a superposition of two one-component plasma models for charges of opposite sign. The free energy of this model sets an upper bound to that of a real plasma. Situations are discussed where this transition should manifest itself in anomalies in the approximate description of a non-ideal plasma.

2009-01-01

169

Field-induced valence transition of Eu(Pd_1_-_xPt_x)_2Si_2  

International Nuclear Information System (INIS)

The magnetic susceptibility and high-field magnetization have been measured for the intermediate valence system Eu(Pd_1_-_xPt_x)_2Si_2 with 0#<=#x#<=#0.15. A first-order valence transition is observed for all the compounds under high field of 100 T at low temperatures. This valence transition is of first order accompanied with a large hysteresis, which is in contrast to a continuous valence change against temperature. Based on the interconfigurational fluctuation (ICF) model, the temperature- and field-induced valence transitions are discussed. It is found that a first-order valence transition can be induced by magnetic field, even if the system shows a continuous valence transition against temperature. Metamagnetic behavior at finite temperatures is also understood qualitatively by the ICF model. copyright 1997 The American Physical Society.

170

Politics and the Dilemma of Meaningful Access to Education: The Nigerian Story. CREATE Pathways to Access. Research Monograph No. 56  

Science.gov (United States)

This paper makes a case for "good politics for good education", with special reference to Nigeria. It surveys the impact of good and bad politics on the attainment of Meaningful Access to education with special focus on Nigeria's Universal Basic Education (UBE) programme. Good politics is to be likened to what the French call "la politique au sense noble du terme" (politics in the noble sense of the term--or statesmanship) while bad politics is to be likened to a "politique politicienne" (mere divisive politicking, or politics in its raw form). Politics in its raw form is concerned with seeking power for self-aggrandisement while politics in its noble form is concerned with seeking power for public good. In situations where good politics prevails, educational policies, programmes and delivery processes tend to produce the desirable outcome of "children passing through school and the school also passing through them". By ...

2011-01-01

171

Two-phase flow regime transition in large diameter vertical pipes  

Energy Technology Data Exchange (ETDEWEB)

The two-phase flow regime transition in a large diameter (I.D.=200mm) vertical pipe was experimentally investigated using a dual-sensor optical probe. The flow transitions from bubbly to chum without an intermediate slug flow regime as the air flow rate is increased. The transition boundaries developed for bubbly to slug flow in small diameter pipes are compared to the bubbly to chum flow transition of the present experiment. The bubbly to chum transition occurs at a void fraction of about 0.15 compared to 0.25 for bubbly to slug transition in small diameter pipes. The radial distribution of bubble diameter, bubble frequency, bubble velocity and local void fraction were obtained using a dual-sensor optical probe at different flow conditions. The Probability Density Function (PDF) and Cumulative Distribution Function (CDF) of the bubble velocity and size are used ...

2002-07-01

172

Two-phase flow regime transition in large diameter vertical pipes  

International Nuclear Information System (INIS)

The two-phase flow regime transition in a large diameter (I.D.=200mm) vertical pipe was experimentally investigated using a dual-sensor optical probe. The flow transitions from bubbly to chum without an intermediate slug flow regime as the air flow rate is increased. The transition boundaries developed for bubbly to slug flow in small diameter pipes are compared to the bubbly to chum flow transition of the present experiment. The bubbly to chum transition occurs at a void fraction of about 0.15 compared to 0.25 for bubbly to slug transition in small diameter pipes. The radial distribution of bubble diameter, bubble frequency, bubble velocity and local void fraction were obtained using a dual-sensor optical probe at different flow conditions. The Probability Density Function (PDF) and Cumulative Distribution Function (CDF) of the bubble velocity and size are used ...

2002-06-02

173

Superconductivity in transition-metal germanium systems  

International Nuclear Information System (INIS)

The variation in the superconducting properties of various binary alloys of transition metal-germanium systems was surveyed by studying sputter deposited samples prepared under various conditions. The primary interest has been to study the formation of the stoichiometric A-15 compounds T_3Ge.

174

Smoking and All-Cause Mortality among a Cohort of Urban Transit Operators  

UK PubMed Central (United Kingdom)

This study assesses the contribution of smoking to all-cause mortality among a primarily minority cohort of urban transit operators. Survey and medical exam data, obtained from 1,785 workers (61% African...Full Text Available

2008-09-01

175

Phenotypic Transition of the Collecting Duct Epithelium in Congenital Urinary Tract Obstruction  

UK PubMed Central (United Kingdom)

Epithelial-mesenchymal transition (EMT) has emerged in recent years as an important process in the development of organ fibrosis in many human diseases. Our previous experience in a nonhuman primate...Full Text Available

2010-01-01

176

Nonlinearity in bacterial population dynamics: Proposal for experiments for the observation of abrupt transitions in patches  

UK PubMed Central (United Kingdom)

An explicit proposal for experiments leading to abrupt transitions in spatially extended bacterial populations in a Petri dish is presented on the basis of an exact formula obtained through an analytic...Full Text Available

2008-12-02

177

LYN is a mediator of epithelial-mesenchymal transition and target of dasatinib in breast cancer  

UK PubMed Central (United Kingdom)

Epithelial-mesenchymal transition (EMT), a switch of polarized epithelial cells to a migratory, fibroblastoid phenotype, is considered a key process driving tumor cell invasiveness and metastasis....Full Text Available

2010-03-15

178

Hyperfine splitting in the rotational levels of the C/sub 2/H molecule  

Energy Technology Data Exchange (ETDEWEB)

The hyperfine splitting in the rotational levels of the C/sub 2/H molecule is calculated as far as N = 10. Line strengths and transition probabilities are determined for permitted transitions with DN = 1, DF = 0, +- 1.

1980-11-01

179

Heat transfer augmentation in the transition region and low Reynolds number turbulent flows  

Energy Technology Data Exchange (ETDEWEB)

The authors report experimental results of heat transfer in the region of transition to turbulence. The augmentation was induced through deployment of periodically placed cylindrical eddy promoters in parallel plane channel flows. Eight different configurations were used. The presence of eddy promoters displaced the point of transition from Reynolds number values of 1500 for the plane channel to around 400 for the least stable case. The value of Nusselt number at the transition for eddy promoters cases was up to 2.5 times higher than the one for the plane channel at the transition. Furthermore, the lower the transition Reynolds number, the higher the Nusselt number at the transition. For the cases where the diameter of the promoters was small and/or the pitch large, the heat transfer results in the transition region were consistent with ...

1995-12-31

180

Evidence for modular evolution in a long-tailed pterosaur with a pterodactyloid skull  

UK PubMed Central (United Kingdom)

The fossil record is a unique source of evidence for important evolutionary phenomena such as transitions between major clades. Frustratingly, relevant fossils are still comparatively rare, most transitions...Full Text Available

2010-02-07

181

Dependence of thermal responses of seeds on membrane transitions  

UK PubMed Central (United Kingdom)

Transitions at 28-32°C in membranes of many kinds of seeds influence their germination and subsequent growth. Changes at 28-32°C in the rates of loss of endogenous amino acids from imbibed...Full Text Available

1979-02-01

182

An objective indicator for two-phase flow pattern transition  

Energy Technology Data Exchange (ETDEWEB)

This work concerns the development of a methodology the objective of which is to characterize and diagnose two-phase flow regime transitions. The approach is based on the fundamental assumption that a transition flow is less stationary than a flow with an established regime. During the first time, the efforts focused on: (1) the design and construction of an experimental loop, allowing to reproduce the main horizontal two-phase flow patterns, in a stable and controlled way; (2) the design and construction of an electrical impedance probe, providing an imaged information of the spatial phase distribution in the pipe; and (3) the systematic study of the joint time-frequency and time-scale analysis methods, which permitted to define an adequate parameter quantifying the unstationarity degree. During the second time, in order to verify the fundamental assumption, a series of experiments were conducted, the objective of which was to demonstrate the ...

1998-08-01

183

An objective indicator for two-phase flow pattern transition  

International Nuclear Information System (INIS)

This work concerns the development of a methodology the objective of which is to characterize and diagnose two-phase flow regime transitions. The approach is based on the fundamental assumption that a transition flow is less stationary than a flow with an established regime. During the first time, the efforts focused on: (1) the design and construction of an experimental loop, allowing to reproduce the main horizontal two-phase flow patterns, in a stable and controlled way; (2) the design and construction of an electrical impedance probe, providing an imaged information of the spatial phase distribution in the pipe; and (3) the systematic study of the joint time-frequency and time-scale analysis methods, which permitted to define an adequate parameter quantifying the unstationarity degree. During the second time, in order to verify the fundamental assumption, a series of experiments were conducted, the objective of which was to demonstrate the ...

1998-08-01

184

Magnetic forming coil design and development summary report  

Science.gov (United States)

Magnetic forming coil design and development

1964-01-01

185

ELECTRICAL AND DIAGNOSTIC ASPECTS OF ELECTROHYDRAULIC AND MAGNETIC FORMING  

Science.gov (United States)

Discussion of an electrohydraulic and magnetic forming process

1963-01-01

186

A STUDY TO DETERMINE THE DEFORMATION ...  

Science.gov (United States)

... crystals and polycrystals. Nevertheless, explosive forming, magnetic forming, etc., are all high-strain-rate processes that ...

1963-04-01

187

X-ray observation of a. sqrt. 3 x. sqrt. 3 superlattice in KC/sub 8/ at high pressure  

Energy Technology Data Exchange (ETDEWEB)

A single-crystal x-ray study under pressure reveals a phase transition from an in-plane 2x2 commensurate potassium superstructure to a new ..sqrt..3x..sqrt..3 commensurate superstructure. This is the first such transition to be observed; it is related to the recently discovered staging transition of KC/sub 8/ under pressure. In addition this staging transition was observed to occur more slowly and at much lower pressures than in the reported neutron-scattering experiment on highly oriented pyrolytic graphite samples. 13 references, 2 figures.

1985-05-15

188

Transition probabilities of rotational levels in "1"7"7Ta  

International Nuclear Information System (INIS)

... capture radioisotopes energy levels excited states intermediate mass nuclei

189

Three-quasiparticle states in "1"7"7Ta  

International Nuclear Information System (INIS)

... transitions lutetium 175 target mev range 10-100 multipolarity neutrons parity

190

The structure of the transitional N=59 nucleus "1"0"1Mo  

International Nuclear Information System (INIS)

... fermions interacting boson model molybdenum 101 neutron-rich isotopes

1987-03-23

192

Study of #beta#"- decay of "1"0"1Mo and "1"0"1Tc nuclei  

International Nuclear Information System (INIS)

... radioisotopes coincidence methods energy-level transitions gamma radiation

1998-09-08

194

Rotational band-structures in transitional odd-A nuclei  

International Nuclear Information System (INIS)

... deformed nuclei eigenvalues even-odd nuclei gold 195 hamiltonians iridium

195

Real-time neutron diffraction measurements of the kinetics of first-order phase transitions  

International Nuclear Information System (INIS)

The wide-angle neutron diffractometer recently installed at the HFIR has the capability of performing time-resolved or time-slicing measurements. One of the interesting problem areas the authors have explored using this time-slicing function of the diffractometer is the kinetics of structural changes occurring after a temperature jump across a value at which a first-order phase transition occurs. Two measurements of this sort have been carried out: the phase III to II transition in RbNO_3 and the transition between the alpha and beta phases in Sn.

1985-03-01

196

Power Beaming, Orbital Debris Removal, and Other Space ...  

Science.gov (United States)

... transition to couple the emitted spontaneous radiation with the ammonia molecules and thus provide more amplification [2]. ...

2010-03-01

197

Odd-A Ir nuclei studied by (#alpha#,xn) reaction  

International Nuclear Information System (INIS)

... alpha reactions angular distribution energy-level transitions iridium 185 iridium

1974-06-10

198

Neutron transition multipole moment for /sup 88/Sr(#alpha#,#alpha#')/sup 88/Sr (2"+, 1.84 MeV)  

International Nuclear Information System (INIS)

The neutron transition multipole moment, M/sub n/, for (0"+#->#2"+, 1.84 MeV) transition is inferred by measuring the (#alpha#,#alpha#') angular distribution at E/sub #alpha#/ = 50 MeV and comparing it with a microscopic distorted-wave Born approximation calculation. Proton transition densities are taken from electron scattering data. M/sub n//M/sub p/ is found to be substantially less than N/Z in agreement with the (p,p') result.

199

Neutron scattering study on the normal-incommensurate phase transition in K2ZnCl4  

Energy Technology Data Exchange (ETDEWEB)

The normal-incommensurate phase transition in K2ZnCl4 was studied by neutron scattering measurements. A well-defined soft phonon behavior was not observed above the normal-incommensurate transition temperature of Tsub(i)=288C. Diffuse scattering develops around(h,0,1 +- 0.3) as temperature approaches Tsub(i) from above, and the peak intensity obeys a Curie-Weiss law above Tsub(i). The results indicate that the normal-incommensurate phase transition in K2ZnCl4 can be interpreted as an order-disorder process.

1984-12-01

200

Low-lying positive-parity states in "1"0"1Tc  

International Nuclear Information System (INIS)

... beta decay energy levels energy-level transitions internal conversion

201

Isomer sup(187m)Ir and its decay scheme  

International Nuclear Information System (INIS)

... comparative evaluations energy-level transitions half-life internal conversion

1974-01-29

202

Elastic constants and volume changes associated with two high-pressure rhombohedral phase transformations in vanadium  

Energy Technology Data Exchange (ETDEWEB)

We present results from ab-initio electronic-structure calculations of mechanical properties of the rhombohedral phase of vanadium reported in recent experiments (R Ia), and other predicted high-pressure phases (R Ib and bcc), focusing on properties relevant to dynamic experiments. We find that of the three transitions the largest volume collapse (1.3%) is for the R Ia to R Ib transition. Calculations of the single crystal and polycrystal elastic constants reveal a remarkably small discontinuity across the phase transitions even at zero temperature where the transitions are first order.

2007-10-16

204

Decay of "1"0"1Mo and "1"0"1Tc  

International Nuclear Information System (INIS)

... beta decay coincidence spectrometry energy levels energy-level transitions

205

Collective model for the odd-mass transitional nucleus "1"8"7Ir  

International Nuclear Information System (INIS)

... collective model hamiltonians iridium 187 matrix elements nuclear cores

1976-06-15

206

#gamma#-#gamma# angular correlation for "1"0"1Tc transitions  

International Nuclear Information System (INIS)

... correlation beta-minus decay coincidence spectrometry experimental data

207

Transition rates of electrons in superheavy elements  

International Nuclear Information System (INIS)

Transition rates for electrons in the superheavy elements Z = 114, 126, 134, 145, 164 and 173 are calculated. K, L and M-shells are considerd as final states. The 2s - 1s stransition of multipolarity M1 is dominant for Z = 173 with a transition time of 10"-"1"8s. The radial expectation values and #sq root# are given. (orig.).

208

Transition of rotating Bianchi type-IX cosmological model into an inflationary era  

Energy Technology Data Exchange (ETDEWEB)

A Bianchi type-IX cosmological model has been found as a solution of Einstien's vacuum field equations with a cosmological constant. The solution represents a rotating generalziation fo the de Sitter universe. This universe shows a transition to exponential expansion and the vorticity begins to decay exponentially at the grand-unified-theory time. The point of time for this transition is independent of the magnitude of the vorticity. During the Guth inflationary era the vorticity decays by a factor of the order 10 US.

1986-02-15

209

Transition of rotating Bianchi type-IX cosmological model into an inflationary era  

International Nuclear Information System (INIS)

A Bianchi type-IX cosmological model has been found as a solution of Einstien's vacuum field equations with a cosmological constant. The solution represents a rotating generalziation fo the de Sitter universe. This universe shows a transition to exponential expansion and the vorticity begins to decay exponentially at the grand-unified-theory time. The point of time for this transition is independent of the magnitude of the vorticity. During the Guth inflationary era the vorticity decays by a factor of the order 10"-"1"4"2.

210

Phase transitions in multiplicative competitive processes  

Science.gov (United States)

We introduce a discrete multiplicative process as a generic model of competition. Players with different abilities successively join the game and compete for finite resources. Emergence of dominant players and evolutionary development occur as a phase transition. The competitive dynamics underlying this transition is understood from a formal analogy to statistical mechanics. The theory is applicable to bacterial competition, predicting novel population dynamics near criticality.

2005-07-01

211

Performance of the transition radiation detector in D{Phi}  

Energy Technology Data Exchange (ETDEWEB)

The transition radiation detector (TRD) for the D{Phi} experiment is currently in operation at Fermilab. Transition radiation production, which has been clearly observed in the collider data, makes the TRD a valuable tool to discriminate electrons and hadrons. We describe an algorithm based on the truncated energy, and illustrate its use for top signal and background. (authors). 7 refs., 6 figs., 2 tabs.

1994-12-31

212

K_#beta#/K_#alpha# X-Ray Intensity Ratio Studies on the Valence Electronic States of 3d-Transition Metals in some of their Compounds  

International Nuclear Information System (INIS)

Our studies on K#beta#/K#alpha# X-ray intensity ratios of some of the technologically important 3d-transition metal compounds have been reviewed. Comparison of the experimental results with single-configuration Dirac-Fock calculations provided important information on the valence states of the transition metals in various compounds, which can be helpful in understanding the nature of bonding in the compounds. (author)

2000-02-01

213

In-Use Performance Comparison of Hybrid Electric, CNG, and Diesel Buses at New York City Transit  

Energy Technology Data Exchange (ETDEWEB)

The National Renewable Energy Laboratory (NREL) evaluated the performance of diesel, compressed natural gas (CNG), and hybrid electric (equipped with BAE Systems? HybriDrive propulsion system) transit buses at New York City Transit (NYCT). CNG, Gen I and Gen II hybrid electric propulsion systems were compared on fuel economy, maintenance and operating costs per mile, and reliability.

2008-06-01

214

Frequency evaluation of the doubly forbidden $^1S_0\\to ^3P_0$ transition in bosonic $^{174}$Yb  

CERN Document Server

We report an uncertainty evaluation of an optical lattice clock based on the $^1S_0\\leftrightarrow^3P_0$ transition in the bosonic isotope $^{174}$Yb by use of magnetically induced spectroscopy. The absolute frequency of the $^1S_0\\leftrightarrow^3P_0$ transition has been determined through comparisons with optical and microwave standards at NIST. The weighted mean of the evaluations is $\

2008-01-01

215

Two-phase flow modeling in the rod bundle subchannel analysis; Modelisation d'ecoulement a deux phases dans l'analyse du sous-canal de grappe d'assemblages  

Energy Technology Data Exchange (ETDEWEB)

In order to practice a design-by-analysis of thermohydraulics design of BWR fuel rod bundles, the subchannel analysis would play a major role. There, the immediate concern is improvement in its predictive capability of CHF due in particular to the film dryout (boiling transition phenomena: BT) on the fuel rod surface. Constitutive equations in the subchannel analysis formulation are responsible for the quality of calculated results. The constitutive equations are a result of integration of the local and instantaneous description of two-phase flows over the subchannel control volume. In general, they are expressed in terms of subchannel-control-volume- as well as area-averaged two-phase flow state variables. In principle the information on local and instantaneous physical phenomena taking place inside subchannels must be counted for in the algebraic form of the equations on the basis of a more mechanistic modeling approach. They should include ...

2006-07-01

216

Two-phase flow modeling in the rod bundle subchannel analysis  

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows:In order to practice a design-by-analysis of thermohydraulics design of BWR fuel rod bundles, the subchannel analysis would play a major role. There, the immediate concern is improvement in its predictive capability of CHF due in particular to the film dryout (boiling transition phenomena: BT) on the fuel rod surface. Constitutive equations in the subchannel analysis formulation are responsible for the quality of calculated results. The constitutive equations are a result of integration of the local and instantaneous description of two-phase flows over the subchannel control volume. In general, they are expressed in terms of subchannel-control-volume- as well as area-averaged two-phase flow state variables. In principle the information on local and instantaneous physical phenomena taking place inside subchannels must be counted for in the algebraic form of the equations on the basis of a more mechanistic ...

2004-07-01

217

Two-phase flow modeling in the rod bundle subchannel analysis  

International Nuclear Information System (INIS)

In order to practice a design-by-analysis of thermohydraulics design of BWR fuel rod bundles, the subchannel analysis would play a major role. There, the immediate concern is improvement in its predictive capability of CHF due in particular to the film dryout (boiling transition phenomena: BT) on the fuel rod surface. Constitutive equations in the subchannel analysis formulation are responsible for the quality of calculated results. The constitutive equations are a result of integration of the local and instantaneous description of two-phase flows over the subchannel control volume. In general, they are expressed in terms of subchannel-control-volume- as well as area-averaged two-phase flow state variables. In principle the information on local and instantaneous physical phenomena taking place inside subchannels must be counted for in the algebraic form of the equations on the basis of a more mechanistic modeling approach. They should include ...

2006-01-01

218

On the solid-fluid transition zone in welding analysis  

Energy Technology Data Exchange (ETDEWEB)

Equilibrium and energy equations have been developed in describing the solid-fluid transition zone during the melting and solidification of the binary alloys. Due to the existence of the transition region exhibited both solid and fluid phases at the same material point from continuum point of view, mixture theory was utilized to analyze the region. Unlike the Stefan problem, the latent heat due to the phase change appears as a source term in the heat equation. The molten fluid is treated as a thermoviscous and incompressible fluid, whereas the solid is thermoviscoplastic described by the Bodner-Partom/Walker type of constitutive equations. Thermal mechanical behaviors of the solid and the fluid phases are determined separately because of insignificant mechanical interactions between them. Volume fractions of the phases are obtained according to the equilibrium phase diagram. The simulation process of the transition zone and ...

1993-01-01

219

Gauge effects on phase transitions in superconductors  

CERN Document Server

Classic and recent results for gauge effects on the properties of the normal-to-superconducting phase transition in bulk and thin film superconductors are reviewed. Similar problems in the description of other natural systems (liquid crystals, quantum field theory, early universe) are also discussed. The relatively strong gauge effects on the fluctuations of the ordering field at low spatial dimensionality D and, in particular, in thin (quasi-2D) films are considered in details. A special attention is paid to the fluctuations of the gauge field. It is shown that the mechanism in which these gauge fluctuations affect on the order of the phase transition and other phase transition properties varies with the variation of the spatial dimensionality D. The problem for the experimental confirmation of the theoretical predictions about the order of the phase transitions in gauge systems is discussed.

2006-01-01

220

Chemistry of polynuclear transition-metal complexes in ionic liquids.  

Science.gov (United States)

Transition-metal chemistry in ionic liquids (IL) has achieved intrinsic fascination in the last few years. The use of an IL as environmental friendly solvent, offers many advantages over traditional materials synthesis methods. The change from molecular to ionic reaction media leads to new types of materials being accessible. Room-temperature IL have been found to be excellent media for stabilising transition-metal clusters in solution and to crystallise homo- and heteronuclear transition-metal complexes and clusters. Furthermore, the use of IL as solvent provides the option to replace high-temperature routes, such as crystallisation from the melt or gas-phase deposition, by convenient room- or low-temperature syntheses. Inorganic IL composed of alkali metal cations and polynuclear transition-metal cluster anions are also known. Each of these areas will be discussed briefly in this contribution. ...

2011-07-11

221

Atomic mechanism of glass-to-liquid transition in simple monatomic glasses  

British Library Electronic Table of Contents (United Kingdom)

The atomic mechanism of a glass-to-liquid transition in a monatomic Lennard-Jones (LJ) glass was studied using the molecular dynamics (MD) method. Glassy models were heated up from low temperature at two different heating rates and a glass-to-liquid transition found to occur at the higher heating rate. The temperature dependence of the potential energy, mean-squared-displacements (MSD) of the atoms and the self-intermediate scattering function indicate clearly that a glass transition occurs in the system. The atomic mechanism of the glass-to-liquid transition was investigated by analyzing the spatio-temporal arrangement of liquid-like atoms in the system upon heating. Liquid-like atoms were detected using the Lindemann-melting-like criterion. Upon heating, liquid-like atoms occur at temper...

2011-01-01

222

Heterodifunctional ligands derived from monooxidized Bis(phosphino)amines. Synthesis and transition metal (Molybdenum(0), Tungsten(0), Rhodium(I), Palladium(II), and Platinum(II)) complexes of (Diphenylphosphino)(diphenylphosphinothioyl)- and (Diphenylphosphino) (diphenylphosphinoselenoyl)phenylamine, Ph[sub 2]PN(Ph)P(E)PH[sub 2] (E = S, Se). Crystal and molecular structure of the Pt(II) Complex [Cl[sub 2]P[ovr tPPh[sub 2]N(Ph)P(S)]Ph[sub 2  

Energy Technology Data Exchange (ETDEWEB)

Bis(diphenylphosphino)phenylamine can be selectivity oxidized by S or Se in toluene or hexane solvents to the monooxidized thioyl or selenoyl products Ph[sub 2]PN(PH)PPh[sub 2]=E, (E = S, Se). These compounds act as bidentate chelate ligands toward metal complexes forming (CO)[sub 4]M(LL) (M = Mo, W), CO(Cl)Rh(LL), and Cl[sub 2]M(LL), (M = Pt, Pd) where (LL) is the thioyl or selenoyl derivative of the aminobis(phosphine). IR and NMR data are given for all complexes. The carbonyl infrared stretching frequencies show that the chelates form with the phosphine cis to any CO which is present. The [sup 31]P NMR of all complexes of two doublets except for the Rh complexes wherein the Rh spin also couples to phosphorous to produce two doublets of doublets. The [sup 2]J[sub PP] values range from 56 to 112 Hz. [sup 1]J[sub PSe] coupling provide valuable assistance for the assignment of the phosphorus resonances which range widely from 55 to 126 ppm for ...

1993-12-08

223

Effect of silver addition on the formation and deposition of titania nanoparticles produced by liquid flame spray  

Energy Technology Data Exchange (ETDEWEB)

In this study, liquid flame spray (LFS) was used to produce titania, silver and silver-titania deposits of nanoparticles. Titanium(IV)ethoxide (TEOT) and silver nitrate in ethanol solutions were used as precursors and sprayed into turbulent hydrogen-oxygen flame. Production rates of 1.5-40 mg/min of titania were used with silver additions of 1, 2, 4, and 8 wt% compared to titania. Nanoparticle deposits were collected by thermophoretic sampling at six different axial distances from the flame torch head: 3, 5, 10, 12, 15, and 20 cm, of which the all but the last one occurred inside the flame. The deposit samples were analysed by TEM and SAED analysis. The powder samples of the particles were also collected by electric precipitator to XPS and specific surface area analysis. Particle size and effective density after the flame in the aerosol were analysed with SMPS and ELPI. The results from the previous studies i.e. controlling the particle size by setting the production rates of the ...

2007-08-15

224

A dinuclear Ni(I) system having a diradical Ni2N2 diamond core resting state: synthetic, structural, spectroscopic elucidation, and reductive bond splitting reactions.  

Science.gov (United States)

One-electron reduction of the square-planar nickel precursor (PNP)NiCl ( 1) (PNP (-) = N[2-P(CHMe 2) 2-4-methylphenyl] 2) with KC 8 effects ligand reorganization of the pincer ligand to assemble a Ni(I) dimer, [Ni(mu 2-PNP)] 2 ( 2), containing a Ni 2N 2 core structure, as inferred by its solid-state X-ray structure. Solution magnetization measurements are consistent with a paramagnetic Ni(I) system likely undergoing a monomer dimer equilibrium. The room-temperature and 4 K solid-state X-band electron paramagnetic resonance (EPR) spectra display anisotropic signals. Low-temperature solid-state X-band EPR data at 4 K reveal rhombic values g z = 1.980(4), g x = 2. 380(4), and g y = 2.225(4), as well as a forbidden signal at g = 4.24 for the Delta M S = 2 half field transition, in accord with 2 having two weakly interacting metal centers. Utilizing an S = 1 model, full spin Hamiltonian simulation of the low-temperature EPR spectrum on the solid sample was achieved by ...

2008-10-15

225

The Nuclear Smuggling International Technical Working Group: Making a difference in combating illicit trafficking  

International Nuclear Information System (INIS)

Full text: The ITWG was first formed in 1995 for the purpose of fostering international cooperation for combating illicit trafficking of nuclear materials. The initial focus for the ITWG was on the development of nuclear forensics to help answer attribution questions regarding nuclear materials of unknown origin. More recently, the ITWG has also expanded its focus to include detection of nuclear materials during transit. This paper presents some of the key developments by this group and their potential impact for combating nuclear smuggling. The initial focus of the ITWG was to write a status report on international cooperation on nuclear smuggling forensic analysis. This 26-page report summarized previous work on nuclear forensics and gave an initial analysis on prioritizing techniques and methods for forensic analysis regarding source and route attribution. This report was submitted to the G-8 countries, and shortly thereafter, nuclear ...

2002-10-21

226

Transverse and longitudinal excitation modes in interacting multispin systems  

International Nuclear Information System (INIS)

Magnetic excitation in coupled multispin system is studied theoretically focusing on Cu_2Fe_2Ge_4O_1_3 and Cu_2CdB_2O_6 as typical examples of such system. These compounds consist of spin dimer and spin monomer parts and show an antiferromagnetic phase transition at low temperatures due to the spin monomer part. A multispin containing a spin dimer and spin monomers is treated as a basis unit. The multispin forms a spin multiplet and its energy levels are separated into high and low regions reflecting the characteristic energies of the dimer and monomer parts. We regard the system as interacting multispins and apply an extended Holstein-Primakoff theory by introducing bosons for each energy level of a spin multiplet. In the low-energy region, the obtained magnon dispersion and dynamical spin correlation function agree quantitatively with experimental results of inelastic neutron scattering performed in Cu_2Fe_2Ge_4O_1_3. Analyzing dynamical spin ...

2010-08-01

227

Transition armature technology. Progress report No. 2, August 1--September 30, 1991  

Energy Technology Data Exchange (ETDEWEB)

This second report covers the period August 1 to September 30, 1991. During this period we modified our approach to Task 1 (Hybrid Armature study) with the addition of a numerical simulation of the steady state plasma brush length with a 1-D, four-phase equation of state code. A test fixture was designed and fabrication begun on a plasma brush test fixture for hybrid studies. It will be powered by a 140 kJ, 1 MA capacitor bank on loan to the project. Diagnostic data collection with 20 channels of digitizers and data reduction with a microvax were also arranged. Sliding friction of a solid armature was simulated and found to form a vapor layer at velocities below 2 km/s. The simulations indicated that higher interface pressure results in vapor boundary layer formation at lower velocity. If there is also a minimum interface pressure required to commutate high currents, then an optimum interface pressure will probably result. Plans for a launcher test bed were begun ...

1991-12-31

228

Software for production scheduling in hydro systems  

Energy Technology Data Exchange (ETDEWEB)

The report presents an integrated software system developed at the Norwegian Electric Power Research Institute (EFI), for production scheduling, maintenance handling, network security analysis, inflow forecasting, and load forecasting. The integrated software is being developed with focus on hydro-dominated power supply systems. In specific terms it is expected that application of the software will improve the operational decisions, and make the planning process more effective. The optimal scheduling of hydro resources poses severe computational problems in system operations planning. This necessitates problem decomposition. In the EFI approach, planning is split into three main levels: long-term, mid-term and short-term planning. The long-term planning aims at evaluating the seasonal and pluriannual handling of regional storages in view of firm power supply obligations, inflow statistics, main hydraulic and electric transit limitations, and the available options ...

1991-02-01

229

On the anatomy of the adsorption heat versus loading as a function of temperature and adsorbate for a graphitic surface.  

Science.gov (United States)

In this paper we review and classify the various patterns of isosteric heat versus loading for adsorption of gases on graphitised thermal carbon black at temperatures ranging from below the 3D triple point to temperatures above it, but less than the 3D critical point. We have identified the features of heat curve and highlighted the microscopic origin of these features. The patterns vary with temperature and with the relative strength of the fluid-fluid interaction and solid-fluid interaction. For simple adsorptives (by simple we meant there is no strong association between fluid particles), the heat curve is typified by fluid-fluid attraction and layering phenomena. For adsorptives showing strong association such as water, ammonia and methanol, the heat curve essentially begins below the condensation heat and then approaches it as loading is increased. This is mainly due to the strong hydrogen bonding in these fluids. A third group includes adsorptives such as benzene, where the heat ...

2008-05-24

230

Nonaqueous synthesis of metal oxide nanoparticles: Short review and doped titanium dioxide as case study for the preparation of transition metal-doped oxide nanoparticles  

Science.gov (United States)

The liquid-phase synthesis of metal oxide nanoparticles in organic solvents under exclusion of water is nowadays a well-established alternative to aqueous sol-gel chemistry. In this article, we highlight some of the advantages of these routes based on selected examples. The first part reviews some recent developments in the synthesis of ternary metal oxide nanoparticles by surfactant-free nonaqueous sol-gel routes, followed by the discussion of the morphology-controlled synthesis of lanthanum hydroxide nanoparticles, and the presentation of structural peculiarities of manganese oxide nanoparticles with an ordered Mn vacancy superstructure. These examples show that nonaqueous systems, on the one hand, allow the preparation of compositionally complex oxides, and, on the other hand, make use of the organic components (initially present or formed in situ) in the reaction mixture to tailor the morphology. Furthermore, obviously even the crystal structure can differ from ...

2008-07-15

231

Identifying surface structural changes in layered Li-excess nickel manganese oxides in high voltage lithium ion batteries: A joint experimental and theoretical study  

Energy Technology Data Exchange (ETDEWEB)

High voltage cathode materials Li-excess layered oxide compounds Li[Ni{sub x}Li{sub 1/3-2x/3}Mn{sub 2/3-x/3}]O{sub 2} (0 < x < 1/2) are investigated in a joint study combining both computational and experimental methods. The bulk and surface structures of pristine and cycled samples of Li[Ni{sub 1/5}Li{sub 1/5}Mn{sub 3/5}]O{sub 2} are characterized by synchrotron X-Ray diffraction together with aberration corrected Scanning Transmission Electron Microscopy (a-S/TEM). Electron Energy Loss Spectroscopy (EELS) is carried out to investigate the surface changes of the samples before/after electrochemical cycling. Combining first principles computational investigation with our experimental observations, a detailed lithium de-intercalation mechanism is proposed for this family of Li-excess layered oxides. The most striking characteristics in these high voltage high energy density cathode materials are (1) formation of tetrahedral lithium ions at voltage less than 4.45 V and (2) ...

2011-09-06

232

D & D screening risk evaluation guidance  

Energy Technology Data Exchange (ETDEWEB)

The Screening Risk Evaluation (SRE) guidance document is a set of guidelines provided for the uniform implementation of SREs performed on decontamination and decommissioning (D&D) facilities. Although this method has been developed for D&D facilities, it can be used for transition (EM-60) facilities as well. The SRE guidance produces screening risk scores reflecting levels of risk through the use of risk ranking indices. Five types of possible risk are calculated from the SRE: current releases, worker exposures, future releases, physical hazards, and criticality. The Current Release Index (CRI) calculates the current risk to human health and the environment, exterior to the building, from ongoing or probable releases within a one-year time period. The Worker Exposure Index (WEI) calculates the current risk to workers, occupants and visitors inside contaminated D&D facilities due to contaminant exposure. The Future Release Index (FRI) calculates the ...

1995-09-01

233

Caustic stress corrosion cracking studies at 288 C (550 F) using the straining electrode technique--comparison of Alloy 600, Alloy 800, and Type 304 stainless steel  

International Nuclear Information System (INIS)

Constant pull rate tests were conducted on tensile specimens of Inconel Alloy 600, Incoloy Alloy 800, and Type 304 stainless steel in deaerated 10% NaOH solution at 288 C (550 F) with a cover gas of 5% H_2 in N_2. The pull rate used for most experiments was 3.3 x 10"-"6 cm/s, which corresponds to an initial strain rate of 3 x 10"-"6 s"-"1. The electrical potential of the specimens was controlled by a potentiostat using a nickel wire as a hydrogen reference electrode. Under open circuit conditions, Type 304 stainless steel specimens cracked rapidly, but Alloys 600 and 800 specimens exhibited only ductile fracture. However, cracks readily formed in Alloy 800 specimens at potentials in the +50 to +300 mV range and in Alloy 600 specimens at potentials in the +150 to +250 mV range. Scanning electron microscope (SEM) photographs of some of the cracked specimen surfaces showed the transition from ductile to brittle fracture as a consequence of changes ...

234

REVIEW OF EXPLOSIVE (CHEMICAL) FORMING  

Science.gov (United States)

... explosive (shotgun shells, etc.) method of forming is being replaced--for the most part--by the electri- cal discharge and magnetic forming methods. ...

1965-04-01

238

METHOD OF FORMING THIN MAGNETIC FILM  

J-STORE (Japan)

Full Text Available

2007-10-04

242

Untitled - NASA Technical Reports Server  

Science.gov (United States)

the techniques employed at present, some of which, like magnetic forming and hotdrape forming, are in experimental stages. Published October 1965. ...

243

SELECTED LISTING OF ECHNOLOGY UTILIZATION PUBLICATIONS  

Science.gov (United States)

as magnetic forming and hot-drape forming. Details about the 25 techniques discussed incorporate the most recent improvements and ...

244

A GENERAL STUDY OF PROCESSES FOR THE ...  

Science.gov (United States)

... fields, materials can be subjected to energy densities exceeding those realized in high explosives, a fact which forms the basis for magnetic forming ...

1962-11-01

245

Line shapes for some specific transitions in Hydrogenic, Lithium-like, and Helium-like ions  

Energy Technology Data Exchange (ETDEWEB)

A set of computer codes have been developed to produce spectral line shapes of highly stripped ions for a number of transitions in Hydrogenic, Helium-like and Lithium-like species. The choice of the transitions has been dictated largely by the laser compression experiments. The transitions of Hydrogenic species are: Lyman ..cap alpha..; Lyman ..beta..; Lyman ..gamma..; Lyman delta; Balmer ..cap alpha..; and Balmer ..beta... The transitions of Helium-like species are: 1s/sup 2/(/sup 1/S/sub 0/)-1s2p(/sup 1/P); 1s/sup 2/(/sup 1/S/sub 0/)-1s3p(/sup 1/P); 1s/sup 2/(/sup 1/S/sub 0/)-1s4p(/sup 1/P) and the associated dipole-forbidden components. The transitions of Lithium-like species are the entire n = 2 to n = 3 and n = 4 complexes.

1980-12-29

246

High resolution spectroscopy of second overtone transitions in solid parahydrogen  

Energy Technology Data Exchange (ETDEWEB)

The high resolution spectrum of the parahydrogen Q{sub 3}(0) transition at 11758 cm{sup -1} has allowed specific quantum state assignment of the ten lines which compose this transition. The transition cannot occur unless a dipole moment is induced in the parahydrogen by an external field. The quadrupole field of an impurity o-H{sub 2} molecule provides this field, and the transition occurs in the orientationally dependent field of the orthohydrogen molecule. Transitions induced by the quadrupolar field of the J=1 H{sub 2} in the nearest neighbor as well as in the next nearest neighbor shells have been observed. By lowering the impurity orthohydrogen concentration, the authors have observed lines with linewidths of approximately 15 MHz hwhm with a Ti:Sapphire laser having a sensitivity of 3x10{sup -5} ({Delta}I/I) using the toneburst method. Additionally, the second vibrational ...

1995-12-31

247

Field-induced valence transition of Eu(Pd{sub 1{minus}x}Pt{sub x}){sub 2}Si{sub 2}  

Energy Technology Data Exchange (ETDEWEB)

The magnetic susceptibility and high-field magnetization have been measured for the intermediate valence system Eu(Pd{sub 1{minus}x}Pt{sub x}){sub 2}Si{sub 2} with 0{le}x{le}0.15. A first-order valence transition is observed for all the compounds under high field of 100 T at low temperatures. This valence transition is of first order accompanied with a large hysteresis, which is in contrast to a continuous valence change against temperature. Based on the interconfigurational fluctuation (ICF) model, the temperature- and field-induced valence transitions are discussed. It is found that a first-order valence transition can be induced by magnetic field, even if the system shows a continuous valence transition against temperature. Metamagnetic behavior at finite temperatures is also understood qualitatively by the ICF model. {copyright} {ital 1997} {ital The American Physical Society}

1997-05-01

248

Dipole response of {sup 88}Sr up to the neutron-separation energy  

Energy Technology Data Exchange (ETDEWEB)

Dipole and quadrupole excitations in the semimagic N{sup .} = 50 nucleus {sup 88}Sr were investigated at the superconducting electron linear accelerator ELBE with bremsstrahlung produced at electron energies of 9.0, 13.2, and 16.0 MeV. About 160 {gamma} transitions were identified up to 12 MeV. By using polarized photons linear polarizations of about 50 {gamma} transitions were measured. In the energy range of 6 - 12 MeV there is only one M1 transition while all other transitions have E1 character. Statistical methods were applied in order to filter out inelastic transitions and to correct the intensities of the ground-state transitions for their branching ratios. The photoabsorption cross section obtained in this way provides information about the extension of the Giant Dipole Resonance towards energies below the neutron-separation energy. The experimental ...

2007-07-01

249

Determination and characteristics of the transition to two-phase slug flow in small horizontal channels  

Energy Technology Data Exchange (ETDEWEB)

Two-phase pressure drop and fluctuating static pressures were measured in a small horizontal rectangular channel (hydraulic diameter = 5.44 mm). The two-phase fluid was an air/water mixture at atmospheric pressure tested over a mass flux range of 50 to 2,000 kg/m[sup 2] [center dot] s. Two-phase flow patterns were identified and an objective method was found for determining the flow pattern transition from bubble or plug flow to slug flow. The method is based on an RMS static pressure measurement. In particular, it is shown that the transition is accompanied by a clear and abrupt increase in the RMS pressure when plotted as a function of mass quality. Use of the RMS pressure as a two-phase flow pattern transition indicator is shown to have advantages over pressure-versus-time trace evaluations reported in the literature. The transition is substantiated by a clear local change in slope in the curve of ...

1994-03-01

250

Structural Phase Transition in AuZn Alloys  

Energy Technology Data Exchange (ETDEWEB)

AuxZn1-x alloys undergo a shape memory martensitic transformation whose temperature and nature (continuous or discontinuous) is strongly composition dependent. Neutron diffraction experiments were performed on single crystals of x=50 and 52 to explore the structural changes occurring at the transition temperature. A transverse modulation with wavevector q0=(1/3,1/3,0) develops below the transition temperature, with no observable change in lattice parameter. However, the Bragg peak width shows a broadening suggesting an unresolved rhombohedral distortion similar to what has been observed in NiTi-Fe alloys.

2009-05-03

251

Rigid muffin-tin approximation for the electron-phonon interaction in transition metals  

Energy Technology Data Exchange (ETDEWEB)

Progress in calculating the electron-phonon parameters of transition metals has been based on either the rigid muffin-tin approximation (RMTA) or the fitted modified tight-binding approximation (FMTBA). The RMTA has been shown to be remarkably accurate for average electron-phonon properties, but there are indications that RMTA matrix elements may be too small at low momentum transfer. An attempt is made to demonstrate these assertions concerning the accuracy of RMTA and the numerous electron-phonon calculations are placed in a broader perspective by a demonstration of how they can be used to explain the trends in the strength of the electron-phonon coupling among the transition metals and the A-15 compounds. (GHT)

1980-01-01

252

Phase transitions for modified Erd\\"os-R\\'enyi processes  

CERN Document Server

A fundamental and very well studied region of the Erd\\"os-R\\'enyi process is the phase transition at n/2 edges in which a giant component suddenly appears. We examine the process beginning with an initial graph. We further examine the Bohman-Frieze process in which edges between isolated vertices are more likely. While the positions of the phase transitions vary, the three processes belong, roughly speaking, to the same universality class. In particular, the growth of the giant component in the barely supercritical region is linear in all cases.

2010-01-01

253

Investigations of electronic transitions and photodissociation of the bromine molecule  

Science.gov (United States)

The electronic transitions and photodissociation of the bromine molecule were studied in the visible-near UV continuum using dynamic simulation. The molar extinction coefficients in this study were obtained in numerical calculations. The quantum yields of the spin-orbit Br*(2 P 1/2) product at different photon frequencies were determined. Time-dependent density functional theory was used to analyze the highest five occupied and lowest five unoccupied Br2 orbitals. The transition to the 1? u state was found to be most probable in the visible-near UV absorption range.

2008-12-01

254

E1 and E3 transition rates in the sdf-IBA  

Energy Technology Data Exchange (ETDEWEB)

The E1 and E3 transition operators in the sdf-IBA model are discussed. An effective E1 operator containing one- and two-body terms explains very well the E1 data in transitional and rotational nuclei. The E1 parameters for rotational nuclei are obtained by imposing a constraint on the IBA model namely, the validity of Alaga rules for ``pure K`` states. The systematic behavior of the octupole strength is well reproduced using a one-body octupole operator. The anomalously large fragmentation of the low-energy octupole strength in non-rotational nuclei is shown to be a signature of the O(6) dynamical symmetry.

1994-11-01

255

Boiling transition under thermal hydraulic instability in rod bundle  

International Nuclear Information System (INIS)

Experiments have been performed on the electrically heated rod bundles to investigate the characteristics of the boiling transition under flow oscillation (OSBT) during thermal hydraulic instability. After determining the instability threshold power (Q/sub OS/), the electrical power to the test section was increased further up to the threshold power (Q/sub OSBT/) at which it was detected by the thermocouples that the boiling transition (BT) occurred and the heater rod temperature reached 613 K. Experimental results show that Q/sub OSBT/ is larger than Q/sub OS/ by a certain margin, which depends on the test conditions.

256

Why the United States Must Deploy a National Missile ...  

Science.gov (United States)

... transItion to more capable space-based interceptors as ... ten wtth bmlogtcal, and thirty with chemical weapons. ... are becoming the weapon of choice ...

2011-05-14

257

Two-phase flow regime map predictions under microgravity  

International Nuclear Information System (INIS)

In this paper, the widely used models of Taitel-Dukler and Weisman et al. are extrapolated to microgravity levels to compare predicted flow pattern boundaries for horizontal and vertical flows. Efforts have been made to analyze how the two-phase flow models available in the literature predict flow regime transitions in microgravity. The models of Taitel-Dukler and Weisman et al. have been found to be more suitable for extrapolation to a wide range of system parameters than the other two-phase flow regime maps available in the literature. The original criteria for all cases are used to predict the transition lines, except for the transition to dispersed flow regime in case of the Weisman model for horizontal flow. The constant 0.97 on the righthand side of this correlation should be two times that value, i.e., 1.94, in order to match this transition line in their original paper.

1988-01-01

259

Thermal energy storage system with stearic acid as phase change material  

Energy Technology Data Exchange (ETDEWEB)

A simple tube-in-tube heat exchanger system for thermal energy storage employing stearic acid as PCM has been investigated. The performance and heat transfer characteristics of such a system were studied. Phase transition temperature range and times were measured and the speed of the phase transition front was computed. The melting front was found to move in the radial direction inward as well as in the axial direction from the top toward the bottom of the phase change material PCM tube. The speed of the melting front is enhanced by a convection heat transfer mechanism in the melted PCM. The heat transfer rate and, consequently, phase transition time can be altered by changing the water inlet temperature to the heat exchanger. In addition, a faster phase transition is realized by placing the heat exchanger in a horizontal position rather than a vertical one. (Author)

1994-10-01

260

Theory of the crystal-liquid phase transition  

Science.gov (United States)

The SCF approximation is used in a statistical theory of melting based on equality of the chemical potentials. The results for the melting points of the inert gases are close to the observed values.

1967-02-01

261

The cross sections of (n, x) nuclear reactions on Pb and Bi at the neutron energy 14.6 MeV  

International Nuclear Information System (INIS)

... compton spectrometers cross sections energy resolution energy-level transitions

2000-06-14

262

Strongly perturbed rotational bands in the "1"8"7Ir and "1"8"9Ir  

International Nuclear Information System (INIS)

... alpha beams energy-level transitions gamma spectra iridium 187 iridium 189

1973-06-19

264

Spin-density-wave transition and #mu#SR in the heavy-fermion Ce(Ru, T)_2Si_2, T = Rh, Pd  

International Nuclear Information System (INIS)

... 900526-11-8 277 p. MATERIALS SCIENCE antiferromagnetic materials cerium

1999-02-28

265

Process for the production of a particularly finely divided, homogeneous transition metal phosphide and transition metal chalcogenide. Verfahren zum Herstellen besonders feinteiliger, homogener Uebergangsmetallphosphide und Uebergangsmetallchalkogenide  

Energy Technology Data Exchange (ETDEWEB)

The purpose of the invention is a process for the production of a particularly finely divided, homogeneous transition metal phosphide and transition metal chalcogenide of Daltonian stochiometry by the conversion of at least one powder transition metal or a transition metal alloy with phosphorus or with a chalcogen at raised temperature, which is characterized by the fact that the conversion is carried out in the presence of at least one inert finely divided auxiliary material which is soluble in water and does not sinter together at the reaction temperature, and that the conversion produce removes the auxiliary material. Even relatively small quantities of the auxiliary material are sufficient to ensure rapid and homogeneous conversion of the reaction partners to the reaction product having a large surface. A ratio of 1 part by volume of a mixture of a transition metal and ...

1980-06-26

266

Periodic perturbations producing phase-locked fluctuations in visual perception  

UK PubMed Central (United Kingdom)

This paper describes a novel psychophysical and analytical technique, called periodic perturbation, for creating and characterizing perceptual waves associated with transitions in visibility...Full Text Available

267

Parities of strong dipole ground state transitions in /sup 88/Sr  

Energy Technology Data Exchange (ETDEWEB)

The unknown parities of five strong dipole states between 6 and 8 MeV in /sup 88/Sr are shown to be negative.

1981-09-01

268

Parities of strong dipole ground state transitions in "8"8Sr  

International Nuclear Information System (INIS)

The unknow parities of five strong dipole states between 6 and 8 MeV in "8"8Sr are shown to be negative. (orig.).

269

Palladium- and Copper-Catalyzed Arylation of Carbon-Hydrogen Bonds  

UK PubMed Central (United Kingdom)

The transition-metal-catalyzed functionalization of C-H bonds is a powerful method for generating carbon-carbon...Full Text Available

2009-08-18

270

Onclas U9800 - NASA Technical Report Server (NTRS)  

Science.gov (United States)

the probability of its spontaneous radiation de-excitation increases. ... consider spontaneous radiation transitions. We will examine the ...

271

On penetration effect in M1 component of 70.45 keV #gamma#-transition in "1"7"7Ta  

International Nuclear Information System (INIS)

... gamma radiation l conversion m conversion mev range 10-100 mixing ratio

1987-04-14

272

Nociceptive and Anxiety-Like Behavior in Reproductively Competent and Reproductively Senescent Middle-Aged Rats  

UK PubMed Central (United Kingdom)

BackgroundChanges in levels of estradiol and progesterone that occur with the transition to reproductive senescence may influence nociception or affect.Full Text Available

2009-01-01

273

Neutron transition multipole moment for /sup 88/Sr(. cap alpha. ,. cap alpha. ')/sup 88/Sr (2/sup +/, 1. 84 MeV)  

Energy Technology Data Exchange (ETDEWEB)

The neutron transition multipole moment, M/sub n/, for (0/sup +/..-->..2/sup +/, 1.84 MeV) transition is inferred by measuring the (..cap alpha..,..cap alpha..') angular distribution at E/sub ..cap alpha../ = 50 MeV and comparing it with a microscopic distorted-wave Born approximation calculation. Proton transition densities are taken from electron scattering data. M/sub n//M/sub p/ is found to be substantially less than N/Z in agreement with the (p,p') result.

1989-04-01

274

Neurocysticercosis, a Persisting Health Problem in Mexico  

UK PubMed Central (United Kingdom)

BackgroundThe ongoing epidemiological transition in Mexico minimizes the relative impact of neurocysticercosis (NC) on public health. However, hard data on the disease frequency...Full Text Available

275

Magnetocaloric and magnetoresistance studies of GdPd{sub 2}Si  

Energy Technology Data Exchange (ETDEWEB)

The compound GdPd{sub 2}Si, which is reported to order antiferromagnetically at 13 K, has been investigated by heat capacity and electrical resistivity measurement in the presence of external magnetic fields. In contrast to an earlier report, the zero-field heat capacity and resistivity data indicate two magnetic transitions at 13 and 17 K. The external magnetic field substantially influences the resistivity and heat capacity of the compound around the magnetic ordering temperature. The magnetocaloric effect, which is calculated from in-field heat capacity data, is quite large around the magnetic transition temperature. The magnetoresistance is also large near the magnetic ordering temperature. The metamagnetic transition is observed for 10 kOe magnetic field both in magnetocaloric and in magnetoresistance data. The metamagnetic transition strongly influences the magnetocaloric effect and ...

2001-01-22

276

Magnetocaloric and magnetoresistance studies of GdPd_2Si  

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 metamagnetic transition strongly influences the magnetocaloric effect and magnetoresistance, ...

2001-01-22

277

Kepler: Transit Detection - Kepler - NASA  

Science.gov (United States)

Nov 12, 2010 ... The adaptive, nonparametric matched filter algorithm suggested by Kay ... For the point design of a 4 sigma single event SNR the combined NR ...

279

Gastrointestinal transit after transverse colostomy: study of solid radiopaque markers progression and others clinical and radiological events - analysis of 20 cases; Transito gastrintestinal apos fechamento de transversostomia: estudo atraves da progressao de marcadores solidos radiopacos e de outros eventos clinicos e radiologicos - analise de 20 casos  

Energy Technology Data Exchange (ETDEWEB)

The gastrointestinal transit was studied in 20 patients with loop transverse colostomies and previously normal colons. This analysis was performed through radiological observation of progression of 20 radiopaque pellets and measurements of its transit time in the various segments of the digestive tract. An evaluation of other related clinical and radiological events was carried out sentimentality's. In order to better understand the influence of the surgical procedure, the study was performed under similar dietary and supportive care conditions and standard radiological studies before and after the re-establishment of transit, thus enabling a comparison with the same individual. (author)

1988-07-01

281

Electric and magnetic dipole transitions in odd-proton rare-earth nuclei  

International Nuclear Information System (INIS)

... gamma cascades kev range 10-100 lifetime lutetium 171 lutetium 173 lutetium

1972-05-01

282

Effect of thermal cycling on the alloy 800/2.25 Cr-1 Mo steel joint  

International Nuclear Information System (INIS)

The critical part of the trimetallic transition joint (type 304 stainless steel/Alloy 800/2.25 Cr-1 Mo steel), the Alloy 800/2.25 Cr-1 Mo steel joint welded with Inconel 182, was subjected to thermal cycling between room temperature and 873 K. The thermal cycling test procedure used produces accelerated failures in transition joints similar to those observed in steam generators of operating power plants. On thermal cycling, precipitation at the weld/ferritic steel interface decreased on post-weld heat treatment. This precipitation increased with increased prior ageing and applied stress. The results of these tests indicated a considerable improvement in performance of the trimetallic transition joint compared to the direct (bimetallic) transition joint. (orig.).

283

E-11775 Cover set - Glenn Research Center - NASA  

Science.gov (United States)

be due to flow separation and reattachment, rather than transition. The analysis predicted a .... lations of Transonic Fan Performance," AGARD Propulsion ...

284

Do spatial effects appear at low dilution rate in chemostat?  

British Library Electronic Table of Contents (United Kingdom)

The chemostat theory on two species competition has shown that the dilution rate where transition of dominance occurs - transition-dilution rate - is independent of limiting-nutrient concentration. However, we obtained the experimental data indicating that the transition-dilution rate changed with variations in limiting-ammonium concentrations, using the chemostat mixed-culture of the cyanobacterium Microcystis novacekii and the green alga Scenedesmus quadricauda. The transition-dilution rate was dependent on the concentration of limiting ammonium in the influx culture medium. We tried to simulate the experimental results. Though the dilution rate has been considered independent of nutrient concentration, we introduce the effective dilution rate that depends on nutrient concentration (ammo...

2009-01-01

285

DISTORTION OF A MAGNETIC FIELD BY THE MOTION OF A ...  

Science.gov (United States)

... No. 52. Metal Complexew-I. Preparation and Physical Properties of Transition Metal Complexes of 6-Mercaptopurine and ,-Mercapto-6, 7-Diphenyl ...

1965-06-01

286

Characterization of cry Genes in a Mexican Bacillus thuringiensis Strain Collection  

UK PubMed Central (United Kingdom)

Mexico is located in a transition zone between the Nearctic and Neotropical biogeographical regions and contains a rich and unique biodiversity. A total of 496 Bacillus thuringiensis...Full Text Available

1998-12-01

287

Characterization of and Concepts for Metroplex Operations  

Science.gov (United States)

7.5.6 Conclusions of the Generic Metroplex Queueing Simulation . ...... the systemwide arrival delays incurred at the metroplex terminal-area ...... assignment rules, estimated nominal transit speeds or times by domain, and stochastic ...

289

Are transition nuclei "1"8"9Ir and "1"8"7Ir triaxial  

International Nuclear Information System (INIS)

... band theory excited states iridium 187 iridium 189 beta decay radioisotopes

1975-06-30

290

Abstract - NASA Technical Report Server (NTRS)  

Science.gov (United States)

This suggests that Ms of the iron nanoparticles is about 125 emu/g, about half of M~u.lk, which contradicts previous reports on transition metals. ...

291

AN EVALUATION OF AN IMPORTANT ADVANCE IN ...  

Science.gov (United States)

... No. 52. Metal Complexes-I. Preparation and Physical Properties of Transition Metal Complexes of 6-Mercaptopurine and 4-Mercapto-6, 7-Diphenyl ...

1965-03-01

292

A note on neutron irradiation effects on transition temperature of A-15 superconducting materials  

International Nuclear Information System (INIS)

The change of superconducting properties after neutron irradiation in A-15 compounds such as Nb_3Sn. Nb_3Al. V_3Ca and V_3Si has been examined. Using the model based on the damage function, the change of transition temperature corresponding to an arbitrary irradiation dose within about 10"2"0n/cm"2 can be predicted with an accuracy of several percent for Nb_3Al. Nb_3Sn and V_3Si if experimental data, namely a pair of irradiation dose and transition temperature, is given. The calculation of transition temperature of neutron irradiated A-15 compounds is much more straightforward than in the case of Pande's model. (author).

293

Conservation laws. Generation of physical fields. Principles of field theories  

CERN Document Server

In the paper the role of conservation laws in evolutionary processes, which proceed in material systems (in material media) and lead to generation of physical fields, is shown using skew-symmetric differential forms. In present paper the skew-symmetric differential forms on deforming (nondifferentiable) manifolds were used in addition to exterior forms, which have differentiable manifolds as a basis. Such skew-symmetric forms (which were named evolutionary ones since they possess evolutionary properties), as well as the closed exterior forms, describe the conservation laws. But in contrast to exterior forms, which describe conservation laws for physical fields, the evolutionary forms correspond to conservation laws for material systems. The evolutionary forms possess an unique peculiarity, namely, the closed exterior ...

2007-01-01

294

The static indentation behavior of composite sandwich panels with thin quasi-isotropic skins  

Science.gov (United States)

The quasi-static normal indentation of sandwich panels with quasi-isotropic laminated composite skins and honeycomb or foam cores, by spherical indentors, has been investigated using experiments and finite element analysis. The experimental program emphasized the effects of indentor size on the resulting load indentation responses, failure mechanisms in the skin and the core, and the measurement of contact areas between indentor and the target. The sandwich panels were indented up to the initiation of skin fracture and the resulting contact data was used to characterize contact power laws. A non-linear finite element model was developed based on the experimental observations to systematically explore the indentation behavior of diverse sandwich configurations and to investigate the contact pressure distributions. The finite element model was used as an experimental tool in the development of a simple non-dimensional semi-empirical model that was based on the Graeco-Latin-square ...

2001-01-01

295

Self-consistent augmented-plane-wave electronic-structure calculations for the A15 compounds V_3X and Nb_3X, X = Al, Ga, Si, Ge, and Sn  

International Nuclear Information System (INIS)

We have performed self-consistent (SC) band structure calculations for the A15 compounds V_3X and Nb_3X, X = Al, Ga, Si, Ge, and Sn, using the augmented-plane-wave (APW) method. Relativistic effects (except the spin-orbit interaction) have been included in each SC cycle, along with corrections to the usual muffin-tin approximation. The latter apply the APW wave functions outside of the muffin-tin spheres to compute the interstitial charge densities and potentials. The resulting interstitial potential has full cubic symmetry (no spherical averaging), although a spherically averaged muffin-tin form is retained inside the spheres. The final SC potentials were used to generate energies and wave functions on a cubic mesh of 35 k points in 1/48th of the Brillouin zone. These results were interpolated onto a finer mesh of 969 k points using a symmetrized Fourier method; the densities of states (DOS), N (E), were determined using tetrahedral integration. These accurate ...

296

Pathway and Surface Mechanism Studies of 1,3-butadiene Selective Oxidation Over Vanadium-Molybdenum-Oxygen Catalysts  

Energy Technology Data Exchange (ETDEWEB)

The partial oxidation of 1,3-butadiene has been investigated over VMoO catalysts synthesized by sol-gel techniques. Surface areas were 9-14 m{sup 2}/g, and compositions were within the solid solution regime, i.e. below 15.0 mol % MoO{sub 3}/(MoO{sub 3} + V{sub 2}O{sub 5}). Laser Raman Spectroscopy and XRD data indicated that solid solutions were formed, and pre- and post-reaction XPS data indicated that catalyst surfaces contained some V{sup +4} and were further reduced in 1,3-butadiene oxidation. A reaction pathway for 1,3-butadiene partial oxidation to maleic anhydride was shown to involve intermediates such as 3,4-epoxy-1-butene, crotonaldehyde, furan, and 2-butene-1,4-dial. The addition of water to the reaction stream substantially increased catalyst activity and improved selectivity to crotonaldehyde and furan at specific reaction temperatures. At higher water addition concentrations, furan selectivity increased from 12% to over 25%. The catalytic effects of ...

2002-05-27

297

[111] phonon dispersion in Nb_3Sn  

International Nuclear Information System (INIS)

It is shown that the extended softening in k space of the [111] transverse acoustic phonon in Nb_3Sn seen recently by neutron measurements is in agreement with the predictions of a phenomenological Landau description of the structural phase transition in the A-15 compounds. This indicates the feasibility of a calculation of the partial phonon density of states of modes directly coupled to the order parameter driving the structural transition, as a function of temperature.

298

[111] phonon dispersion in Nb3Sn  

Science.gov (United States)

It is shown that the extended softening in k space of the [111] transverse acoustic phonon in Nb3Sn seen recently by neutron measurements is in agreement with the predictions of a phenomenological Landau description of the structural phase transition in the A-15 compounds. This indicates the feasibility of a calculation of the partial phonon density of states of modes directly coupled to the order parameter driving the structural transition, as a function of temperature.

1979-04-01

299

Transitional nuclei and triaxial shapes  

International Nuclear Information System (INIS)

Evidence for triaxial nuclear shapes from families of unique-parity states in transitional odd-A nuclei around mass A=190 and A=130 is reviewed. The experimental data are analysed within the odd-A triaxial core model. Regular two-dimensional band patterns are found in experiment and are shown to be a consequence of broken axial symmetry. Recent theoretical developments are discussed including the question of how stable the triaxial shapes are.

300

Transition of hydrated oxide layer for aluminum electrolytic capacitors  

Energy Technology Data Exchange (ETDEWEB)

A hydrous oxide film for the application as dielectric film is synthesized by immersion of pure aluminum in hot water. From a Rutherford backscattering analysis, the ratio of aluminum to oxygen atoms was found to be 3:2 in the anodized aluminum oxide film, and 2:1 in the hydrous oxide layer. Anodization of the hydrous oxide layer was more effective for the transition of amorphous anodic oxides to the crystalline aluminum oxides.

2007-03-25

301

Thermal conductivity of simple molecular substances at crystal-liquid phase transition  

International Nuclear Information System (INIS)

By the example of CH2Cl2, CF2Cl2, CHF2Cl, C2F6, C2H6, SF6 and C6H12 we have investigated the isobaric thermal conductivity jump at crystal-liquid phase transition. It is shown that the reduction in the thermal conductivity at melting derives from the degree of orientational ordering of the crystals at pre-melting point.

2009-01-01

302

Theoretical transition energies, lifetimes and fluorescence yields of multiply ionized silicon  

Energy Technology Data Exchange (ETDEWEB)

Theoretical x-ray transition energies, lifetimes and partial multiplet fluorescence yields are presented for all spectroscopic terms of electron configurations with a single K-shell vacancy and varying number of electrons in the L-shell and M/sub 1/-subshell for multiply-ionized silicon. 9 tables.

1982-01-01

303

The superconducting critical temperature of radiation damaged A-15 compounds  

International Nuclear Information System (INIS)

A simple model is used to explain the decrease in superconducting critical temperature with damage observed for irradiated A-15 compounds. A truncated t-matrix approximation is used to describe the disorder along the one-dimensional transition metal chains. Three dimensionality is introduced by the inclusion of interaction between transition metal atoms on different chains. Numerical fits to experiment are discussed in the conclusion. (author).

304

Superconducting transition temperature of the nonideal A-15 crystals  

International Nuclear Information System (INIS)

The defect-induced effect on superconducting transition temperature T_c of A-15 compounds is examined. T_c is found from the Eliashberg equations which take into account the defect-induced changes in the electron-phonon spectral function and electron density of states. The dependence of T_c on the defect type in the superconductor is obtained.

305

Solution of Bohr's collective Hamiltonian for transitional odd-mass nuclei  

International Nuclear Information System (INIS)

A numerically feasible method, based on the use of deformed phonons, is developed for the diagonalization of the collective quadrupole Hamiltonian for a system with an odd particle coupled to an anharmonic even core. Examples: the transition from prolate to oblate via #gamma#-unstable shapes and furthermore the hsub(9/2) spectra of the nuclei "1"8"7Ir and "1"9"7Tl. (Auth.).

306

Rubidium 5"2P fine-structure transitions induced by collisions with potassium and caesium atoms  

International Nuclear Information System (INIS)

A diode-laser fluorescence experiment was performed in order to study fine-structure transitions between 5"2P states of rubidium atoms colliding with ground-state potassium or caesium atoms. The Rb(5"2P_3_/_2) state was optically excited and the intensity ratio of sensitized to direct fluorescence was measured. (author).

307

Progress report, December 1, 1979-November 30, 1980. [Chemical poisoning of heterogeneously catalyzed reactions on transition metal surfaces  

Energy Technology Data Exchange (ETDEWEB)

The mechanism of chemical poisoning of model heterogeneously catalyzed reactions on transition metal surfaces is studied. Clean Mo(001) surfaces were characterized; results suggest a first-layer contraction of 10% of the bulk interlayer spacing. Characterization of clean Co(0001) surfaces is underway. Decomposition of formic acid on Mo(001) surfaces is being studied. (DLC)

1980-01-01

308

Penetration effect in the M1 component of "1"7"7Ta #gamma#-transition with energy of 70.45 keV  

International Nuclear Information System (INIS)

The magnetic #beta#-spectrometer of the #pi# #sq root#2 type with 0.07% pulse resolution is used to measure the intensities of interval conversion electrons on L- and M-subshells of 70.45 keV "1"7"7 Ta gamma-transition. The results are analyzed and the values of mixing parameter #sigma#(E2/M1) and penetration parameter #lambda# are obtained.

309

Pd-Na/F double exploding foil photoionization experiment  

Science.gov (United States)

The achievement of inner-shell photoionization of Zn-like Pd by means of two exploding foils is described. This resulted in the soft X-ray transition 3d94s2-3d104p at 46 A. It is shown that the photoionization of inner shell electrons in highly stripped ions can lead to X-ray transitions which may be candidates for X-ray lasers under 50 A.

1990-03-01

310

Officer in Tactical Command and Tactical Data Information Exchange Systems (OTCIXS/TADIXS) and the Transition to the Military Strategic and Tactical Relay System (MILSTAR).  

Science.gov (United States)

The purpose of this thesis is to explore possible difficulties and their solutions in transitioning the OTCIXS/TADIXS subsystems from the present Navy UHF Fleetwide Satellite System to the EHF/SHF MILSTAR System. The research provides a description of the...

1987-01-01

311

Methods of investigation of nuclear matter under the conditions characteristics for transition to quark-gluon plasma  

International Nuclear Information System (INIS)

Features of deep inelastic nuclear reactions proceeding on dense fluctuations of nuclear matter (fluctons) are briefly considered. Fluctons, which can be many-quark bags or drops of quark-gluon plasma, are studied. Their properties are discussed, viz., characteristic parameters of nuclear matter inside a flucton - temperature and density close to the critical values for a phase transition. These values can be reached or exceeded if the flucton-flucton collision events are separated. The separation method is discussed

2002-11-01

312

Massive parallel generation of indistinguishable single photons via the polaritonic superfluid to Mott-insulator quantum phase transition  

International Nuclear Information System (INIS)

We study the possibility of utilizing the superfluid to Mott-insulator quantum phase transition in an array of quantum well exciton-polariton traps to generate indistinguishable single photons in a massive parallel fashion. By means of analytical and numerical methods, the device operations and system properties are examined using realistic experimental parameters. Such a deterministic, massive parallel generation may find new applications in photonic quantum information processing.

2010-12-01

313

Magnetic and valence transitions in CePd_2_-_xMn_xSi_2:L_I_I_I edge study  

International Nuclear Information System (INIS)

We report on solid solution CePd_2_-_xMn_xSi_2 which shows an interesting transition of the Ce-ion from magnetism in a Kondo regime to an intermediate valence state coupled with a strongly magnetic 3d sublattice. ((orig.)).

314

Magnetic and valence transitions in CePd[sub 2-x]Mn[sub x]Si[sub 2]:L[sub III] edge study  

Energy Technology Data Exchange (ETDEWEB)

We report on solid solution CePd[sub 2-x]Mn[sub x]Si[sub 2] which shows an interesting transition of the Ce-ion from magnetism in a Kondo regime to an intermediate valence state coupled with a strongly magnetic 3d sublattice. ((orig.))

1994-04-01

315

Landau-Ginzburg method applied to finite fermion systems: Pairing in nuclei  

Energy Technology Data Exchange (ETDEWEB)

Given the spectrum of a Hamiltonian, a methodology is developed which employs the Landau-Ginsburg theory for characterizing phase transitions in infinite systems to identify phase transition remnants in finite fermion systems. As a first application of our approach we discuss pairing in finite nuclei. (orig.)

2005-09-01

316

Landau theory of the martensitic transition in A-15 compounds  

International Nuclear Information System (INIS)

The martensitic phase transition in the A-15 compounds is treated by expanding the free energy in terms of the order parameters and its spatial gradients. The model used is a modified version of that recently proposed by Gorkov. The predictions for a wide range of physical properties are in good agreement with experimental results for V_3Si and Nb_3Sn lending support to the veracity of the model. 25 refs.

317

Excess transit time as a function of burst current in an exploding bridgewire detonator  

Energy Technology Data Exchange (ETDEWEB)

Transit time, the time from bridgewire burst until breakout of detonation from the output pellet of an exploding bridgewire detonator, was measured as a function of burst current. From this data, in conjunction with known equations for run distance versus pressure, unreacted explosive Hugoniots, and detonation properties of the initial pressing pellet, the run distance in the initial pressing explosive pellet and shock pressure from the exploding bridgewire were determined, both as a function of burst current.

1990-01-01

318

Direct interband dipole-transition selection rules for the O/sub h//sup 3/ space-group compounds  

Energy Technology Data Exchange (ETDEWEB)

The irreducible representations associated with states of dipole symmetry have been calculated for the space groups O/sub h//sup 3/, the space group with the correct symmetry for A-15 phase compounds. Also assembled are the character tables of the O/sub h/3 group. Thus all thedirect interband dipole-transition selection rules for A-15 compounds can easily be determined.

1983-07-01

319

Critical review of analytical correlations for two-phase flow regime transitions  

International Nuclear Information System (INIS)

Two sets of analytical correlations describing transitions between two-phase flow regimes are reviewed and discussed. One, the T-D set, is based on mechanistic models; the other, the Weisman set, on experimental correlations. The T-D set is preferred for horizontal flow, whereas the Weisman set seems preferrable for vertical flow. A computer code (FLOP) based on the T-D theory is described and applied to validate the theory.

1983-06-15

320

Conformational transitions of alternating purine-pyrimidine DNAs in perchlorate ethanol solutions.  

UK PubMed Central (United Kingdom)

Conformational transitions of poly(dA-dC).poly(dG-dT), poly(dA-dT).poly(dA-dT), and other alternating purine-pyrimidine DNAs were studied in aqueous ethanol solutions containing molar concentrations...Full Text Available

1995-11-01

321

Characteristics of boiling transition of tight lattice rod assembly  

International Nuclear Information System (INIS)

Critical power characteristics of tight lattice rod assembly was investigated using a simple-shaped experimental apparatus. An electrically heated rod with four spacers was placed in a circular tube, and boiling transition condition for a rod in an annular geometry was clarified varing annulus clearance. It was found that critical heat flux depends strongly on the clearance accoding as the gap becomes smaller. This results was compared with KfK correlation and the trends were well correlated. (author).

322

Relationship between QRS transition zone and the interventricular septum; Using CT scan  

Energy Technology Data Exchange (ETDEWEB)

The relationship between the QRS transition zone of the standard 12-lead ECG and interventricular septum was studied. The position and the angle to the horizontal line of the interventricular septum were evaluated with computed tomography (CT) and compared to the QRS transition zone. The subjects were 36 patients with no cardiovascular diseases. The patients were divided into 3 groups according to the position of QRS transition zone: V{sub 1}-V{sub 2} (8 cases), V{sub 3}-V{sub 4} (21 cases), and V{sub 5}-V{sub 6} (7 cases). The interventricular septum on CT was directed to the anterior chest wall between V{sub 3} and V{sub 4} in all 3 groups. The mean value of the interventricular septal angle did not differ from group to group, 52.1deg for V{sub 1}-V{sub 2} group, 49.8deg for V{sub 3}-V{sub 4} group, and 48.2deg for V{sub 5}-V{sub 6}. It was concluded that the direction of the interventricular septum was not one of the ...

1991-11-01

323

K beta X-ray transition energies of M-shell-ionized ions of Ti through Ni in a plasma  

Energy Technology Data Exchange (ETDEWEB)

K beta X-ray lines from partially M-shell-ionized ions of titanium through nickel which are produced in vacuum-spark plasmas have been observed systematically for the first time, using a high-resolution curved-crystal spectrometer. Each K beta line is clearly separated into its corresponding charge state. As a result, it is possible to measure the K beta-type transition energies of the M-shell-ionized ions. The transition energies accurately determined are compared with those calculated for iron ions, and the agreement is excellent except for ions having some additional 3d outer-shell electrons or 3s inner-shell vacancies. The square root of the K beta transition frequency is expressed as a linear function of the nuclear charge for isoelectronic sequences. The effective nuclear charges have been also determined for each K beta transition. The 3p electrons do not affect the effective nuclear charges. 10 ...

1985-05-01

324

Experimental study on two-phase flow regime transition from stratified to slug flow in a large-height horizontal duct  

Energy Technology Data Exchange (ETDEWEB)

The prediction of two-phase flow regime in the horizontal pipings during a loss-of-coolant accident (LOCA) is important for safety analysis of a pressurized water reactor (PWR). The flow regime transition conditions for a horizontal two-phase air-water flow were studied using a large-height, horizontal rectangular duct test section. The duct dimensions were 700 mm in height, 100 mm in width and 28.3 m in length. The experimental criterion for the flow regime transition from the stratified to slug flow regimes, in terms of the local void fraction and the non-dimensional gas-liquid relative velocity, agreed qualitatively with the prediction by the Mishima-Ishii model that is based on an idea that the interfacial waves with the largest growth rate will develop into a slug. However, the transition in the experiment occurred at systematically lower (by about 40 %) relative velocities than the prediction by the Mishima-Ishii ...

1992-02-01

325

Effects of relativity and 'atomic structure' in the KLL Auger spectrum of "8"8Sr generated in the EC-decay of "8"8Y  

International Nuclear Information System (INIS)

The KLL Auger electron spectrum of "8"8Sr generated in the EC-decay of "8"8Y has been analyzed at the instrumental resolution of 11 eV using a combined electrostatic spectrometer. Energies and relative intensities of the all nine transitions were determined and compared with theoretical predictions. Our value of 12067.3(12) eV measured for the absolute energy of the dominant KL_2L_3("1D_2) transition was found to be higher by 7.4 eV (i.e., more than 3#sigma#) than that one obtained in a measurement with external excitation. The discrepancy indicates substantial influence of the 'atomic structure effect' on absolute transition energies in our experiment. Very good agreement of the measured 0.14(3) and predicted 0.12 values for the KL_1L_2("3P_0/"1P_1) Auger transition intensity ratio clearly proved the predicted strong influence of the relativistic effects on the KL_1L_2("3P_0) ...

2007-08-01

326

Local Quark-Hadron Duality and Magnetic Form Factors of Bound Proton  

International Nuclear Information System (INIS)

We discuss the consequence of local duality for elastic scattering, and derive a model-independent equation between structure functions at x ? 1 and elastic electromagnetic form factors. Then the electromagnetic form factors of proton are discussed using the quark-hadron duality theory. We also debate the form factor of proton in a bound state. It may be an effective approach to study the form factor of proton in media.

2005-08-01

327

Short Form of the Developmental Behaviour Checklist  

UK PubMed Central (United Kingdom)

A 24-item short form of the 96-item Developmental Behaviour Checklist was developed to provide a brief measure of Total Behaviour Problem Score for research purposes. The short form Developmental...Full Text Available

2007-01-01

328

Measurement of the population densities in Gd atomic vapor using diode laser absorption spectroscopy in UV transitions  

International Nuclear Information System (INIS)

We report on the ultraviolet laser absorption spectroscopy of atomic Gd at 394-554 nm where two transition lines are place very closely by using a frequency-doubled beam of external-cavity diode laser (ECDL). One is from 999.121 to 26337.071 cm-1 and the other from 0 to 25337.755 cm-1. If two transition lines are placed closely within a continuous fine tuning range, the real-time measurement of the atomic excitation temperature is possible without any significant time consumption because at least two transition lines originating from different low-lying energy levels need to be investigated for the Boltzmann-plot. Since the spectral difference between the two transitions is only about 0.195 cm-1 (5.85 GHz), it is possible to record both the absorption spectra simultaneously as shown in Fig. 1. But the transition probabilities (or oscillator strengths) of these lines have not been ...

2003-11-07

329

Extended observation and analysis of the first overtone spectrum of solid parahydrogen  

Energy Technology Data Exchange (ETDEWEB)

The first overtone spectrum of solid parahydrogen with various low ortho impurity levels has been studied in detail using a White-type external multireflection system. For the Q{sub 2{l_arrow}0}(0) transition the authors have observed the fully resolved threefold splitting due to the crystal field effect. Furthermore, the authors have obtained a rich satellite spectrum associated with the transitions Q{sub 2{l_arrow}0}(0) and Q{sub 2{l_arrow}0}(1) at different ortho-H{sub 2} contents revealing information about the ortho-H{sub 2} pair interaction in the second vibrationally excited state of the hydrogen molecule. A preliminary analysis and assignment of these satellite transitions will be presented. Another point of study was the spectral region around 8300 cm{sup -1}, where the double transitions of the type Q{sub 1{l_arrow}0}(n) + Q{sub 1{l_arrow}0}(n{prime}) (n, n{prime} = 0,1) are located. The most ...

1996-12-31

330

Electronic instabilities and the martensitic transition in A-15 compounds  

International Nuclear Information System (INIS)

The structural transition and anomalous properties of the high temperature A-15 superconductors have been investigated from two different standpoints. The first is a Landau theory based on Gorkov's physical model of a Peierls-like charge density wave (CDW) transition involving electronic CDW order parameters coupled to phonon coordinates. Pretransition elastic anomalies, softening of the [1 anti 10] transverse ([1 anti 10] polarized) phonon, sublattice distortions, variation of transition temperature with stress and alloying and other effects have been accurately predicted, and a detailed comparison is made with experimental results. Central peaks in neutron scattering are shown to be non-dynamic in nature and no pretransition forbidden (300) reflection is predicted. The GAMMA_1_2 optic mode does not go soft at the transition, though its frequency is expected to be temperature dependent right up to room ...

331

Untitled - NASA Technical Report Server (NTRS)  

Science.gov (United States)

Principle advantages of magnetic forming for part manufacture appear to lie ... to be an area of great potential for the magnetic forming process. We have a ...

332

Publications Reporting Innovations any Pu - NASA Technical Reports ...  

Science.gov (United States)

at present, some of which, like magnetic forming and hot-drape forming, are in experimental stages. NASA SP-5017 1965 52pp. GPO 40cents ...

333

Physiologic changes during growth and development.  

UK PubMed Central (United Kingdom)

To express growth-related changes in physiologic or other functions in forms usable for kinetic modeling, we are interested in identifying regular relationships that take the form of simple mathematical...Full Text Available

1994-12-01

334

Nucleon Form Factor Measurements and Interpretation  

Energy Technology Data Exchange (ETDEWEB)

The data base for the form factors of the nucleon obtained from elastic ep scattering is discussed, as well as some recent developments in their calculation.

2007-08-22

335

NASA TM X-52248 - NASA Technical Report Server (NTRS)  

Science.gov (United States)

Magnetic Forming (10). - Forming of metals (the metal needs only to be an electrical conductor) is achieved without physical contact ...

336

NASA SPECIAL', PUBLICATIONS" - NASA Technical Reports Server  

Science.gov (United States)

ployed at present, some of which, like magnetic forming and hot-drape forming, are in experimental stages. NASA SP-5017 1965 52 pp. GPO 40 cents ...

338

Cost Estimating - NASA Technical Report Service  

Science.gov (United States)

May 25, 2007 ... This form will generate a bibliography of cost estimating references. The form will search the NASA Technical Report Service (NTRS) database ...

339

The electroweak phase transition at m$_{H}$ $\\appprox$ m$_{W}$  

CERN Document Server

We study the finite temperature electroweak transition with non-perturbative lattice Monte Carlo simulations. We find that it is of first order, at least for Higgs masses up to 80 GeV. The critical temperature of the phase transition is found to be smaller than that determined by a 2-loop renormalization group improved effective potential. The jump of the order parameter at the critical temperature is considerably larger than the perturbative value. By comparing lattice data and perturbation theory, we demonstrate that the latter, for the computation of the vacuum expectation value of the Higgs field v(T) in the broken phase at given temperature, converges quite well, provided v(T)/T>1. An upper bound on the Higgs mass necessary for electroweak baryogenesis in the light of the lattice data is briefly discussed.

1994-01-01

340

Studies on the superconducting properties of A-15 type intermetallic compounds  

International Nuclear Information System (INIS)

The influence of 3d-transition metal impurities on the superconducting properties of the A-15 compounds V_3Si and V_3Ga have been investigated. In the case of V_3Si, the Fe impurities replacing V were found to have a local moment. A compensation effect was found in this case, resulting in a 20KOe increase in the upper critical field at dilute concentrations of Fe. It was demonstrated that long range order V_3Ga possessed higher transition temperature and upper critical field than found hitherto. Investigations on Nb_3Ge/sub 1-x/Ga/sub x/ films obtained by chemical vapor deposition has clearly shown the relation between the transition temperature and structural characteristics. The influence of generalized defects on the superconducting properties in A-15 type Nb_3X compounds has been discussed.

341

Quasienergy description of the driven Jaynes-Cummings model  

CERN Document Server

We analyze the driven resonantly coupled Jaynes-Cummings model in terms of a quasienergy approach by switching to a frame rotating with the external modulation frequency and by using the dressed atom picture. A quasienergy surface in phase space emerges whose level spacing is governed by a rescaled effective Planck constant. Moreover, the well-known multiphoton transitions can be reinterpreted as resonant tunneling transitions from the local maximum of the quasienergy surface. Most importantly, the driving defines a quasienergy well which is nonperturbative in nature. The quantum mechanical quasienergy state localized at its bottom is squeezed. In the Purcell limited regime, the potential well is metastable and the effective local temperature close to its minimum is uniquely determined by the squeezing factor. The activation occurs in this case via dressed spin flip transitions rather than via quantum activation as in other ...

2010-01-01

342

Possible control scenario of radial electric field by loss-cone-particle injection into helical device  

Energy Technology Data Exchange (ETDEWEB)

The possibility of controlling the radial electric field of toroidal plasmas by injecting high energy electrons along the reversible loss cone orbit of the helical magnetic traps is investigated. It is well known that the radial electric field plays an important role in the confinement improvement scenario especially in the low collisional regime under the physics picture of neoclassical theory. For this purpose, it is made clear that the most suitable particles are transit particles, which show a transition from helically trapped orbits to blocked ones. It is also found that a parallel AC electric field launched from outside assists this transition and makes it possible for particles to penetrate deeply into the plasma. In addition we clarify that the viscosity of the plasma coupled with the helical field configuration provide a bifurcation of plasma states and its stable solution results in confinement improvement. ...

1999-08-01

343

Optical properties of Nb and Mo calculated from augmented-plane-wave band structures  

International Nuclear Information System (INIS)

Nonrelativistic band calculations of Mattheiss for Nb and Petroff and Viswanathan for Mo are used to calculate the imaginary part epsilon_2 of the dielectric function for these metals. The structure resulting from interband transitions in the frequency range 0.1--0.5 Ry is found to give fairly good agreement with experiment. The calculation indicates that structure in epsilon_2 can arise from transitions away from symmetry points and lines in the Brillouin zone. The difficulty in distinguishing between the direct and indirect transition models for epsilon_2 is shown to arise from a lack of strong optical critical points. Predictions of the rigid-band model for the optical properties of Nb-Mo alloys are presented.

344

Online monitoring of steel casting processes using multivariate statistical technologies: From continuous to transitional operations  

British Library Electronic Table of Contents (United Kingdom)

This paper describes a state-of-the-art online monitoring system using multivariate statistical technologies for continuous steel casting process, which was commissioned at Dofasco's No. 2 caster to provide consistent indication of process health for caster's start-up, continuous production and transitional operations. The paper particularly focuses on development of a novel scheme to synchronize process trajectories for monitoring specific transitional operations such as equipment or steel product grade changes. The proposed scheme is demonstrated by several industrial examples with the results showing good detectability of various process abnormalities. With the aid of this fully integrated, innovative monitoring system, Dofasco has generated significant value through improved productivi...

2006-01-01

345

Mechanical properties and fracture behavior of #alpha# particle irradiated type 316 stainless steel at high temperature  

International Nuclear Information System (INIS)

The effect of helium on the mechanical properties and fracture behaviors of a type 316 austenitic steel is presented. Helium implantation was performed by 30-MeV #alpha#-particle injection on very small, thin specimens, using a cyclotron accelerator. Average helium content in the He-deposited region was 50 to 2000 appm He. These specimens showed the transition of fracture mode from transgranular to intergranular fracture in elevated temperature tests. The transition temperature decreased with increase in the amount of implanted helium. For example, in the case of 2000 appm and 500 appm He implantation, the transition temperatures were between 773 and 873 K and 873 and 973 K, respectively. (orig.).

346

Infrared spectroscopy of rovibrational transitions of methyl radicals (CH3, CD3) in solid parahydrogen  

British Library Electronic Table of Contents (United Kingdom)

The n3 and n4 vibrational transitions of CH3 and CD3 isolated in solid parahydrogen were studied by high-resolution infrared spectroscopy. The radicals were produced by in situ UV photolysis of methyl iodides trapped in solid parahydrogen. The observed spectra showed clear rotational fine structures, which were subjected to further splitting due to the electrostatic field of solid parahydrogen. The molecular constants and crystal field parameters of the radicals in solid parahydrogen were determined by analyzing the spectral structures of the n3 and n4 transitions of CD3 by the crystal field theory. The rotational constants of the CD3 radical were found to be only a few percent smaller than those in the gas phase. The determined crystal field parameters indicated significant quantum effect...

2011-01-01

347

Global challenges in energy  

International Nuclear Information System (INIS)

Environmental and security concerns are stimulating global interest in hydrogen power, renewable energy, and advanced transportation technologies, but no significant movement away from oil and a carbon-based world economy is expected soon. Over the longer-term, however, a transition from fossil fuels to a non-carbon-based economy will likely occur, affecting the type of environment future generations may encounter. Key challenges will face the world's energy industry over the next few decades to ensure a smooth transition-challenges which will require government and industry solutions beginning as early as today. This paper identifies four critical challenges in energy and the choices which will have to be made on how best to confront growing pollution caused by fossil fuels and how to facilitate an eventual revolutionary-like transition to a non-carbon-based global economy.

2006-10-01

348

Evaluation of the long-term mechanical behavior in the near-fields considering chemical transitions of barrier materials  

International Nuclear Information System (INIS)

An analysis system for the long-term mechanical behavior of barrier materials (MACBECE: Mechanical Analysis system considering Chemical transitions of BEntonite-based and CEment-based materials) was developed in order to improve the reliability of the evaluation of the hydraulic field which is one of the important environmental conditions in the safety assessment of the TRU waste disposal. MACBECE is the system that calculates the deformation of barrier materials using their chemical property changes as inputs, and subsequently calculates their hydraulic conductivity taking both their chemical property changes and deformation into consideration. By using MACBECE, the long-term deformation and the transition of hydraulic field for the round-type disposal cavities were evaluated, assuming some sets of chemical evolution data as input. Based on the analysis result, it is considered that the influence of the long-term deformation of the barrier ...

2007-04-22

349

Epitaxial bain path in transition metals  

Energy Technology Data Exchange (ETDEWEB)

Epitaxial films grown pseudomorphically on substrates provide a way to stabilise non-equilibrium structures of materials. Obviously, there always is a certain lattice misfit between substrate and film material in its bulk equilibrium structure. In the pseudomorphic regime, this misfit can either lead to the growth of films in a strained bulk structure or even yield structures that are not stable in the bulk. Large misfits do not necessarily imply large lateral stress. Theory can help to predict e.g. geometry, stress and magnetic properties of pseusomorphically grown metal films. In this work, we considered the fcc-bcc epitaxial Bain path of 3d, 4d, and 5d transition metals, which provides a reasonable description of tetragonally distorted films on substrates. We carried out density functional calculations in the implementation of the full potential local orbital program package FPLO. Emphasis is put on similarities among the transition metals.

2010-07-01

350

Continuous Paranematic-to-Nematic Ordering Transitions of Liquid Crystals in Tubular Silica Nanochannels  

CERN Document Server

The optical birefringence of rod-like nematogens (7CB, 8CB), imbibed in parallel silica channels with 10 nm diameter and 300 micrometer length, is measured and compared to the thermotropic bulk behavior. The orientational order of the confined liquid crystals, quantified by the uniaxial nematic ordering parameter, evolves continuously between paranematic and nematic states, in contrast to the discontinuous isotropic-to-nematic bulk phase transitions. A Landau-de Gennes model reveals that the strength of the orientational ordering fields, imposed by the silica walls, is beyond a critical threshold, that separates discontinuous from continuous paranematic-to-nematic behavior. Quenched disorder effects, attributable to wall irregularities, leave the transition temperatures affected only marginally, despite the strong ordering fields in the channels.

2008-01-01

351

Application of chaos theory in identification of two-phase flow patterns and transitions in a small, horizontal, rectangular channel  

Energy Technology Data Exchange (ETDEWEB)

Various measurement tools that are used in chaos theory were applied to analyze two-phase pressure signals with the objective of identifying and interpreting flow pattern transitions for two-phase flows in a small, horizontal rectangular channel. These measurement tools included power spectral density function, autocorrelation function, pseudo-phase-plane trajectory, Lyapunov exponent,s and fractal dimensions. It was demonstrated that the randomlike pressure fluctuations characteristic of two-phase flow in small rectangular channels are chaotic, and governed by a high-order deterministic system. The correlation dimension is potentially a new approach for identifying certain two-phase flow patterns and transitions.

1996-06-01

352

Alkali metal and alkali metal hydroxide intercalates of the layered transition metal disulfides  

International Nuclear Information System (INIS)

The intercalation reaction of some layered transition metal disulfides with alkali metals, alkali metal hydroxides, and tetraalkylammonium hydroxides were investigated. The alkali metal intercalates were prepared in the respective metal-hexamethylphosphoric triamide solutions in vaccuo, and the hydroxide intercalates in aqueous hydroxide solutions. According to the intercalation reaction, the c-lattice parameter was increased, and the increase indicated the expansion of the interlayer distance. In the case of alkali metal intercalates, the expansion of the interlayer distance increased continuously, corresponding to the atomic radius of the alkali metal. On the other hand, the hydroxide intercalates showed discrete expansion corresponding to the effective ionic radius of the intercalated cation. All intercalates of TaS_2 amd NbS_2 were superconductors. The expansion of the interlayer distance tended to increase the superconducting transition ...

353

A strategy of implementation of the improved constitutive equations for the advanced subchannel code  

International Nuclear Information System (INIS)

To develop the advanced subchannel analysis code, the dominant factors that influence the boiling transitional process must be taken into account in the mechanistic constitutive equations based on the flow geometries and the fluid properties. The dominant factors that influence the boiling transitional processes are (1) the gas-liquid re-distribution by cross flow, (2) the liquid film dryout, (3) the two-phase flow regime transition, (4) the droplet deposition, and (5) the spacer-droplet interaction. At first, we indicated the strategy for the development of the constitutive equations for the five dominant factors based on the experimental database by the latest measurement technique and the latest computational fluid dynamics method. Then, the problems of the present constitutive equations and the improvement plan of the constitutive equations were indicated. Finally, the layered structure for the two-phase/three-field ...

2004-10-04

355

The study of "1"0"1Mo decay  

International Nuclear Information System (INIS)

The decay of "1"0"1Mo to levels in "1"0"1Tc has been studied using the three-parameter (#gamma#-#gamma#-t) coincidence system of HpGe-HpGe detectors. According to the coincidence data, the decay scheme was modified. The positions of 221.80, 318.00, 377.90, 452.50, 515.42, 1011.05 and 1759.72 keV transitions have been arranged again, the transition positions of 104.70, 105.95 and 774.15 keV gamma-rays have been assigned for the first time, the positions of 169.00, 590.91, 980.52 and 1431.68 keV transitions have been reconfirmed, the 1508.01 keV gamma-ray was observed simultaneously for the first time and its transition position has been assigned. The #beta#-intensities and the values of log ft of most levels were calculated. (author)

2000-09-01

356

Tachyons and the instability of physical systems  

International Nuclear Information System (INIS)

The problem on the ratio between the instability of physical systems and tachyons is discussed. It is shown that the tachyons participation in the real physical process of the system rearranging does not contradict any principles. It is noted that the tachyons constitute the most significant element of the systems, identifying the instability relative to the phase transition into the stable state.

357

Systematics of average radiative width of heavy nuclides  

Energy Technology Data Exchange (ETDEWEB)

Systematics of neutron capture radiative width were studied in the target element range from Th to Cm. Reduced radiative widths were analyzed with a simple radiative width formula based on E1 transition. Average radiative width is presented with the standard deviation of 15%. (author)

1999-03-01

358

Synthesis of new transition metal chalcogenide complexes and their functions; Atarashii kinzoku karukogenido sakutai no soshutsu to kinou  

Energy Technology Data Exchange (ETDEWEB)

One of our research objectives is to develop chemistry of transition metal chalcogenides which are relevant to new inorganic materials, environmental catalysts, metalloenzymes. In this context, this research project has been aimed at rational syntheses of chalcogenide complexes of electron-deficient transition metals, construction of hetero metallic clusters with high nuclearity, and elucidation of chemical properties characteristic of these metal chalcogenide compounds. We were successful in synthesizing a series of sulfide (selenide)/thiolate complexes of group 4,5 and 6 transition metal elements by making use of C-S bond cleaving reactions and anhydrous chalcogenide reagents. We also achieved construction of unprecedented large chalcogenide clusters of mixed metal systems such as [Cu{sub 4}(dppm){sub 4}MS{sub 4}] [PF{sub 6}]{sub 2} (M=Mo, W), [(Cp*WS{sub 3}Ag{sub 2}){sub 2}({mu}-Br){sub 2}]{sub {infinity}}, and [Cp*{sub ...

1998-12-16

359

Superconductivity in A-15 compounds  

International Nuclear Information System (INIS)

Superconductivity in A-15 compounds is examined in terms of electron pairing induced by exchange of acoustic plasmons. The electronic band structure of Nb_3Sn, V_3Si, and similar materials favor transition temperatures of Tsub(c)approximately20 K. (Auth.).

360

Structure of the triplet of low-lying states in sup 101 Mo  

Energy Technology Data Exchange (ETDEWEB)

The properties of the triplet of low-lying states in {sup 101}Mo have been studied through spectroscopy of the {gamma} radation following thermal neutron capture in {sup 100}Mo and {beta}-decay of {sup 101}Nb and through a measurement of the proton angular distributions in the {sup 100}Mo(d, p) reaction with 14 MeV deuteron energy. The half-lives of the 13.5 keV state and the 57.0 keV 5/2{sup +} state have been measured as 226(7) and 133(7) ns, respectively. These values and the quadrupole/dipole mixing ratios of the 13.5 keV and 43.5 keV transitions yield spin and parity 3/2{sup +} for the 13.5 keV level. The E2 components in the 13.5 (3/2{sup +}->1/2{sup +}) and 43.5 keV (5/2{sup +}->3/2{sup +}) transitions are {le} 8x10{sup -4} and 54(9)%, respectively. The possibility of an additional state near to the 57.0 keV level is discussed. IBFM/PTQM calculations, taking into consideration the transitional character of the ...

1991-06-01

361

Structure of the triplet of low-lying states in "1"0"1Mo  

International Nuclear Information System (INIS)

The properties of the triplet of low-lying states in "1"0"1Mo have been studied through spectroscopy of the #gamma# radation following thermal neutron capture in "1"0"0Mo and #beta#-decay of "1"0"1Nb and through a measurement of the proton angular distributions in the "1"0"0Mo(d, p) reaction with 14 MeV deuteron energy. The half-lives of the 13.5 keV state and the 57.0 keV 5/2"+ state have been measured as 226(7) and 133(7) ns, respectively. These values and the quadrupole/dipole mixing ratios of the 13.5 keV and 43.5 keV transitions yield spin and parity 3/2"+ for the 13.5 keV level. The E2 components in the 13.5 (3/2"+#->#1/2"+) and 43.5 keV (5/2"+#->#3/2"+) transitions are #<=# 8x10"-"4 and 54(9)%, respectively. The possibility of an additional state near to the 57.0 keV level is discussed. IBFM/PTQM calculations, taking into consideration the transitional character of the "1"0"0Mo boson core, account for the ...

362

Semileptonic b to u transition  

CERN Document Server

Experimental studies of charmless semileptonic B decays can be broadly categorized into inclusive and exclusive measurements depending on how the final states are treated. The inclusive method measures the decay rate $\\Gamma(B \\to X_u \\ell \

2007-01-01

363

Sec24C is required for docking the prechylomicron transport vesicle with the Golgi  

UK PubMed Central (United Kingdom)

The rate-limiting step in the transit of dietary fat across the intestinal absorptive cell is its exit from the endoplasmic reticulum (ER) in a specialized ER-to-Golgi transport vesicle, the prechylomicron...Full Text Available

2010-05-01

364

Safety Nets and Scaffolds: Parental Support in the Transition to Adulthood  

UK PubMed Central (United Kingdom)

Using longitudinal data from the Youth Development Study (analytic sample N = 712), we investigate how age, adult role acquisition and attainments, family resources, parent-child relationship...Full Text Available

2011-04-01

365

Role of the presence of transition-metal atoms at the antisites in CrAs, CrSe and VAs zinc-blende compounds  

Energy Technology Data Exchange (ETDEWEB)

In a recent publication [I. Galanakis, K. Ozdog-tilde an, E. Sasiog-tilde lu, B. Aktas, Phys. Rev. B 74 (2006) 140408(R)] we have shown that in the case of CrAs and related transition-metal chalcogenides and pnictides, crystallizing in the zinc-blende structure, the excess of the transition-metal atoms leads to half-metallic ferrimagnetism. The latter property is crucial for spintronic applications with respect to ferromagnets due to the lower stray fields created by these materials. We extend this study to cover the case where the transition-metal atoms sitting at antisites are not identical to the ones in the perfect sites. In Cr-based compounds, the creation of Mn antisites keeps the half-metallic ferrimagnetic character produced also by the Cr antisites. In the case of VAs, Cr and Mn antisites keep the half-metallic character of VAs (contrary to V antisites) due to the larger exchange splitting exhibited by these atoms.

2008-02-15

366

Rate of allosteric change in hemoglobin measured by modulated excitation using fluorescence detection.  

UK PubMed Central (United Kingdom)

We have measured the forward and reverse rates of the allosteric transition of hemoglobin A with three CO molecules bound by using modulated excitation coupled with fluorescence quenching of the DPG...Full Text Available

1989-10-01

367

Proton spin lattice relaxation studies in lithium ammonium sulfate LiNH_4SO_4  

International Nuclear Information System (INIS)

Lithium ammonium sulfate (LAS) undergoes a phase transition at Tsub(c1) = 459.5deg K from a paraelectric phase (phase 1) to a ferroelectric phase (phase II) and again at Tsub(c2) = 283deg K to a polar ferroelastic phase (phase III). Proton spin lattice relaxation investigations in the temperature range 480-77deg K at 10 MHz show discontinuous changes in Tsub(1) at the transition temperatures, indicating first order phase transitions. The absence of the slow motion region (#omega#sub(not)tausub(not)>>1) shows that the ammonium ions are reorienting fast enough to keep the resonance absorption line narrow down to liquid nitrogen temperatures. The possibility of a second minimum and a low activation energy, Esub(a) = 2.659 kcal/mole, in phase III suggest the possibility of tunnelling of the protons at low temperatures. The nature of the transitions have been discussed in the light of the available ...

1978-12-31

368

Preliminary Evaluation of Psychoeducational Support Interventions on Quality of Life in Rural Breast Cancer Survivors Post-Primary Treatment  

UK PubMed Central (United Kingdom)

While most cancer survivors are at risk for being lost in the transition from treatment to survivorship, rural breast cancer survivors face special challenges that might place them at particular...Full Text Available

2009-01-01

369

Point defects in superconductors  

Energy Technology Data Exchange (ETDEWEB)

The federating theme of superconductivity has given rise to a number of experimental studies of point defects in solids as different as transition metals (V, Nb, ...), A-15 compounds (V{sub 3}Si, Nb{sub 3}Ge, ...), or perovskite-like copper oxides. Some of these experiments are presented here. (orig.).

1989-12-01

370

Point defects in superconductors  

International Nuclear Information System (INIS)

The federating theme of superconductivity has given rise to a number of experimental studies of point defects in solids as different as transition metals (V, Nb, ...), A-15 compounds (V_3Si, Nb_3Ge, ...), or perovskite-like copper oxides. Some of these experiments are presented here. (orig.).

371

Phase transitions in the soliton star model  

Energy Technology Data Exchange (ETDEWEB)

The aim of this paper is to obtain the effective potential of the non-topological soliton model at finite temperature with the assumption that the chemical potential {mu} of the system is different from zero and to analyse how the effective potential is influenced by changes in the chemical potential and temperature. (author)

1998-01-01

373

NAME=\\  

Wastenet

...links ensure all of our managed accommodation is easily accessible to both campus sites and our special student arrangement makes travelling on the Metro rapid transit system easily affordable. Our halls are comfortable and they are very reasonable. Download the rents table here Rents 2009-2010 Students living in ...

374

Mechanisms of elementary events in the kinetics of electrical breakdown of polymer and ceramic dielectrics  

Science.gov (United States)

The kinetics of electrical breakdown of thin (15-70 ?m) layers of polymers and ceramics in a constant-sign field at 77-480 K has been investigated. The temperature dependences of the longevity (breakdown waiting time) of both dielectrics have been found to be similar to each other. At elevated temperatures, the longevity of the dielectrics varies exponentially with increasing temperature, and at reduced temperatures, it is temperature-independent (there is an athermal plateau). The mechanisms of elementary events controlling the process of preparation of the dielectrics for breakdown at elevated and reduced temperatures are the thermal-fluctuation over-barrier electron transition from trap to trap and the tunneling (under-barrier) transition, respectively. The hopping electron transport in the field direction gives rise to critical space charges causing breakdown of the dielectrics. The transition barrier heights (trap ...

2011-07-01

375

Light duty utility arm startup plan  

Energy Technology Data Exchange (ETDEWEB)

This plan details the methods and procedures necessary to ensure a safe transition in the operation of the Light Duty Utility Arm (LDUA) System. The steps identified here outline the work scope and identify responsibilities to complete startup, and turnover of the LDUA to Characterization Project Operations (CPO).

1998-09-01

376

Life history plasticity after attaining a dietary threshold for reproduction is associated with protein storage in flesh flies  

UK PubMed Central (United Kingdom)

SummaryBody condition affects the timing and magnitude of life history transitions. Therefore, identifying proximate mechanisms...Full Text Available

2008-12-01

377

Latent transition models with latent class predictors: attention deficit hyperactivity disorder subtypes and high school marijuana use  

UK PubMed Central (United Kingdom)

SummaryAttention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder which is most often diagnosed in childhood with symptoms often persisting into adulthood....Full Text Available

2010-01-01

378

L edge-absorption systematics of some transition-metal (Pd, Ag), main-group-metal (Sn, In), and ionic (CsI) systems  

Energy Technology Data Exchange (ETDEWEB)

The L edge absorption of Pd, Ag, Sn, In, and CsI was measured in order to study the density of states and the unoccupied d states. 4 figures. (DLC)

1982-01-01

380

Intercombination transitions in beryllium-like and boron-like iron  

Energy Technology Data Exchange (ETDEWEB)

Beam-foil spectroscopy techniques have been used to study intercombination transitions in Be-like Fe{sup 22+} and B-like Fe{sup 21+}. The method of time delayed spectroscopy was used to identify the Be-like 2s{sup 2} {sup 1}S{sub 0}-2s2p {sup 3}P{sub 1} and B-like 2s{sup 2}2p {sup 2}P{sub 3/2}-2s2p{sup 2} {sup 4}P{sub 5/2} transitions. Intensity decay curves for these transitions were recorded and level lifetimes were obtained. The latter were found to be 17.5 {+-} 1.5 ns for the Be-like 2s2p {sup 3}P{sub 1} level and 14.8 {+-} 1.0 ns for the B-like 2s2p{sup 2} {sup 4}P{sub 5/2} level. (orig.).

1997-04-01

381

Inhibited spontaneous emission by a Rydberg atom  

Science.gov (United States)

Spontaneous radiation by an atom in a Rydberg state is inhibited by use of parallel conducting planes to eliminate the vacuum modes at the transition frequency. Spontaneous radiation emission is observed to turn off abruptly at the cutoff frequency of the waveguidelike structure, and the natural lifetime is measured to increase by a factor of at least 20.

1985-11-11

382

IDEAS: Problems of Economic Transition, M.E. Sharpe, Inc.  

Wastenet

... (restricted)] 24-53 Cyclicality of Fiscal Policy in Oil-Producing Countries by E. Gurvich & E. Vakulenko & P. Krivenko [Downloadable! (restricted)] 54-75 Russian Energy Efficiency Potential by I. Bashmakov [Downloadable! (restricted)] 76-94 Outlook and ...

383

Hydrogen in metals  

International Nuclear Information System (INIS)

An important application of metal hydrides is as a moderator material in nuclear reactors. The fundamental properties of hydrides are illustrated and an impression given of the current research into hydrogen in transition metals. Phase diagrams, magnetic properties, temperature dependence of the diffusion coefficient, energy level schemes and superconductivity are considered. (C.F.).

384

Glass Transition Behaviors of Ethylene Glycol-Water Solutions Confined within Nano-Pores of Silica Gel  

Science.gov (United States)

Enthalpy relaxation properties of the ethylene glycol (EG) aqueous solutions confined within silica-gel void spaces of 1.1 nm in the average void thickness and 6, 12 and 52 nm in their average diameters were examined by an adiabatic calorimetry to understand the glass transition behavior of the solutions and the rearrangement processes of the molecules. The glass transition temperature Tg of EG was found to decrease with adding the water molecules which are mobile under the condition lacking in the full hydrogen-bond network. Meanwhile, the Tg in the water-rich region showed a rise towards pure water; after a phase separation in a 25 mol% (x = 0.25) EG solution, the Tg was 160 K which was higher than that derived by extrapolating the composition dependence to pure water. The Tg = 160 K is the same as observed in the pure water confined within 1.1 nm voids; this indicates the validity of the interpretation that the glass ...

2008-02-01

385

Formation of the electret state of polymers in a gas discharge plasma  

Science.gov (United States)

The present article studies the electret state of polymers when moving through an alternating-current corona discharge plasma and investigates means for the determination of the transition of the polymeric material from the initial state of the electret when the corona-displaying voltage is increased.

1983-02-01

386

First detection of lamella-gyroid-cylinder phase transition of neat polyethylene-poly(ethylene oxide) diblock copolymers on the basis of synchrotron WAXD/SAXS and infrared/Raman spectral measurements  

International Nuclear Information System (INIS)

The phase transition behaviour of polyethylene-b-poly(ethylene oxide) (PE-b-PEO) diblock copolymer with relatively short chain lengths has been studied on the basis of temperature dependent infrared and Raman spectral measurements and synchrotron WAXD/SAXS simultaneous measurements, from which the concrete structural changes were deduced successfully from the various levels of molecular chain conformation, chain packing mode and higher-order structure. The higher-order structure has been found to transform between lamella, perforated lamella, gyroid, cylinder and sphere structures. The inner structural changes occurring in the polyethylene and poly(ethylene oxide) parts have been related with these morphological changes. The morphological transition from lamella to gyroid occurs with keeping the crystalline state of polyethylene parts. This apparently curious transition can be interpreted reasonably by assuming the ...

2009-08-01

387

Excitonic transitions in InGaP/InAlGaP strained quantum wells  

International Nuclear Information System (INIS)

Excitonic transitions in metalorganic vapor phase epitaxially grown In_xGa_1_-_xP/In_0_._4_8(Al_0_._7Ga_0_._3)_0_._5_2P strained single quantum-well structures are characterized using low-temperature photoluminescence and photoluminescence excitation (PLE) spectroscopies. The structures consist of several uncoupled quantum wells with thicknesses between 1.2 and 11.3 nm, and compositions x of 0.48 (nominally lattice matched) and 0.56 (#approx#0.6% biaxial compressive strain). The photoluminescence spectra exhibit intense peaks over the wavelength range 550--650 nm, with linewidths between 7 and 23 meV depending on the well thickness. The PLE spectra reveal strong heavy-hole and light-hole transitions, as well as higher-order (n=2) transitions in the thicker wells. The heavy-hole/light-hole splitting shows little dependence on well thickness in the strained structures, indicating a relatively large conduction band offset of ...

388

Excitations and electromagnetic transitions for /sup 88/Sr and /sup 90/Zr  

Energy Technology Data Exchange (ETDEWEB)

In this letter we report the outcome for the microscopic approach for the semi-magic nuclei /sup 88/Sr and /sup 90/Zr. For comparison, we have also treated the semi-phenomenological version for the Migdal and SDI force.

1981-10-10

389

Excitations and electromagnetic transitions for /sup 88/Sr and /sup 90/Zr  

Energy Technology Data Exchange (ETDEWEB)

An application of the renormalized random phase approximation to nuclear structure is presented for the semi-magic nuclei /sup 88/Sr and /sup 90/Zr. It is reported the outcome for the microscopic approach in comparison with the semiphenomenological version for the particle-hole forces.

1981-10-10

390

Evaluation of the Sida Support to the Global Safety Partnership.  

Science.gov (United States)

The Global Road Safety Partnership (GRSP) is a global partnership of business, civil society and government working for sustained reduction of road accidents in developing and transition countries. GRSP, which started operations in 1999, has a global secr...

2004-01-01

391

Electronic topological transition in zinc metal? A "6"7Zn-Moessbauer investigation  

International Nuclear Information System (INIS)

The question concerning the existence of an electronic topological transition (ETT) in Zn metal under quasi-hydrostatic pressure at #approx#6.6 GPa caused a considerable controversy in the literature. We briefly review low-temperature "6"7Zn-Moessbauer data and scalar-relativistic augmented plane wave calculations and give a consistent interpretation in terms of an ETT. To highlight some important aspects of the controversy two theoretical and two experimental publications will be discussed in more detail. At present the existence of an ETT in Zn metal is disputed both from an experimental and from a theoretical point of view. The suggestion of a transition to a commensurate spin-density wave at #approx#6.6 GPa instead of an ETT may reconcile the seemingly contradictory results of "6"7Zn-Moessbauer experiments at 4.2 K and of room temperature inelastic neutron scattering measurements. However, it does not explain the anomalies found in ...

2000-11-01

392

Electron momentum spectroscopy of H_2 and D_2: Ionization to ground and excited final states  

International Nuclear Information System (INIS)

The symmetric noncoplanar (e,2e) cross sections (momentum profiles) of H_2 and D_2 for the transitions to the 2p#sigma#_u and 2s#sigma#_g excited ion states have been measured, relative to the ground-state ion transition, using a high-sensitivity multichannel momentum-dispersive electron momentum spectrometer (EMS) at an impact energy of 1200 eV. Newly calculated plane-wave impulse approximation (PWIA) cross sections, based on a full-configuration-interaction H_2 wave function, are compared to the experimental results. These calculations are in better agreement with the experimental results for the transition to the 2s#sigma#_g ion state than the earlier theoretical work of Liu and Smith, Jr. [Phys. Rev. A 31, 3003 (1985)] which has been found to be in error. Nevertheless, significant discrepancies between the relative experimental and theoretical cross sections are observed for the transitions to ...

393

EARLY FLOWERING3 Encodes a Novel Protein That Regulates Circadian Clock Function and Flowering in Arabidopsis  

UK PubMed Central (United Kingdom)

Higher plants use photoperiodic cues to regulate many aspects of development, including the transition from vegetative to floral development. The EARLY FLOWERING3 (ELF3)...Full Text Available

2001-06-01

394

Chaotic system of two-phase flow in a small, horizontal, rectangular channel.  

Science.gov (United States)

Various measurement tools that are used in chaos theory were applied to analyze two-phase pressure signals with the objective of identifying and interpreting flow pattern transitions for two-phase flows in a small, horizontal rectangular channel. These me...

1995-01-01

395

Are there acoustic plasmons?  

Science.gov (United States)

A survey of theoretical research on acoustic plasmons is given and prospects for the observation of these elusive modes are examined. Possible acoustic plasmon contributions to the transition temperatures of the superconducting A-15 compounds are considered. Directions for future experiments and theory are suggested.

1981-09-01

396

Amygdala projections to central amygdaloid nucleus subdivisions and transition zones in the primate  

UK PubMed Central (United Kingdom)

In rats and primates, the central nucleus of the amygdala (CeN) is most known for its role in responses to fear stimuli. Recent evidence also shows that the CeN is required for directing attention...Full Text Available

2009-03-17

397

Alexandria's Eastern Harbor, Egypt: Pollen, Microscopic Charcoal, and the Transition from Natural to Human-Modified ...  

Science.gov (United States)

... doi: 10.2112/JCOASTRES-D-09-00089.1 Alexandria's Eastern Harbor, Egypt: Pollen, Microscopic Charcoal, and ... STANLEY, J.-D. an...

398

Advances in metallography. Fortschritte in der Metallographie  

Energy Technology Data Exchange (ETDEWEB)

The 52 papers discuss the following subjects: 1. Preparation and structural development; 2. Structural constitution; 3. Structural formation and phase transition; 4. Structure and mechanical properties; 5. Structural formation of metallic and nonmetallic materials; 6. Quantitative metallography, and 7. Quality assurance.

1983-01-01

399

Abnormal phase transition in BiNbO4 powders prepared by a citrate method  

British Library Electronic Table of Contents (United Kingdom)

Triclinic b-BiNbO4 prepared below 750^oC and above 1040^oC (denoted as Low-b and High-b, respectively) and pure orthorhombic a-BiNbO4 at 900^oC were successfully derived from a citrate method and the phase transition from b-BiNbO4 to a-BiNbO4 was first observed in BiNbO4 powders. This phenomenon proves that the abnormal phase transition from b-BiNbO4 to a-BiNbO4 exists in BiNbO4 powder system. The synthesis of Low-b powders can be attributed to the formation of the intermediate phase of Bi5Nb3O15 by the citrate method. With increasing temperature, the Low-b phase gradually turns into a-BiNbO4 due to the thermodynamically metastable state of Low-b. We also identified that the stress in pellet format can accelerate the phase transition from Low-b to a phase of BiNbO4 in comparison with powde...

2011-01-01

400

A correlation between the heavy element content of transiting extrasolar planets and the metallicity of their parent stars  

CERN Document Server

Nine extrasolar planets with masses between 110 and 430M are known to transit their star. The knowledge of their masses and radii allows an estimate of their composition, but uncertainties on equations of state, opacities and possible missing energy sources imply that only inaccurate constraints can be derived when considering each planet separately. Aims: We seek to better understand the composition of transiting extrasolar planets by considering them as an ensemble, and by comparing the obtained planetary properties to that of the parent stars. Methods: We use evolution models and constraints on the stellar ages to derive the mass of heavy elements present in the planets. Possible additional energy sources like tidal dissipation due to an inclined orbit or to downward kinetic energy transport are considered. Results: We show that the nine transiting planets discovered so far belong to a quite homogeneous ensemble that is ...

2006-01-01

403

Weeksite at Les Bois Noirs (Loire)  

International Nuclear Information System (INIS)

French (Sep - Oct 1977). France Deliens, Michel. Published in summary form

1977-10-01

406

THE APPLICATION OF STEEP PULSE CURRENTS TO THE ...  

Science.gov (United States)

... Title : THE APPLICATION OF STEEP PULSE CURRENTS TO THE ELECTROHYDRAULIC AND MAGNETIC FORMING OF METALS. ...

1966-04-01

411

Organizational Culture and Changes of Command  

Science.gov (United States)

... The OER Support Form and NCOER Counselling Worksheet provide a way to match individual and organizational goals. ...

1991-04-26

412

Novel Antidrugabuse Peptide  

International Science & Technology Center (ISTC)

Natural Biologically Active HLDF6 Peptide as Potential Preparation for Correction of Different Drugabuse Forms

413

NASA Technical Reports Server - Magnetic forming coil design and ...  

Science.gov (United States)

Site Error There's a problem with your browser or settings. ...

414

Magnetic forming studies  

Science.gov (United States)

Elastodynamic approach to measuring stress-strain relationship of uniaxially stressed wire, and

1967-01-01

415

Magnetic forming of resistive materials  

Science.gov (United States)

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

1969-01-01

423

Coupled Growth and Division of Model Protocell Membranes  

UK PubMed Central (United Kingdom)

The generation of synthetic forms of cellular life requires solutions...Full Text Available

2009-04-22

430

CLINICOBACTERIOLOGICAL AND EPIDEMIOLOGICAL ...  

Science.gov (United States)

... Salmonella. Vdgella and Brucela also to the diagnosis of the septic- tylphoidal and enteric form of human peendotuber- auloals. ...

1963-11-01

434

AUTOMATED TECHNOLOGY KNOWLEDGE BASE  

Science.gov (United States)

MAGNETIC FORMING .............. MAGNETIC INDUCTION ............ MAGNETIC MATERIALS ............ MAGNETIC MEASUREMENT .......... MAGNETIC PERMEABILITY . ...

435

Vibrational Circular Dichroism: A developing spectroscopic technique for peptide and protein conformational studies  

International Nuclear Information System (INIS)

Electronic circular dichroism (ECD) of the n-#pi# and #pi# -#pi# transitions of the amide groups in the ultraviolet has become an indispensable tool for qualitative characterization of proteins in solution. Since the existence of such a spectrum (that is, of natural optical activity) comes from the three dimensional interaction of the chromophores in the molecule, CD is exquisitely sensitive to molecular conformation. However, in proteins, the amide transitions available in the near UV are limited in number and are broads and overlapping. Interactions among them yield information about the polymeric backbone, but since such amide electronic excitation are relatively delocalized, the resulting

1996-11-01

436

Universal spectrochemical series of six-coordinate octahedral metal complexes for modifying the ligand field splitting.  

Science.gov (United States)

We studied a novel universal spectrochemical series of six-coordinated octahedral 3d transition metal complexes, which can be used for any combination of central metal atom and ligand molecules. A two dimensional spectrochemical series could be used to estimate the ligand field splitting energy of not only known compounds but also the unknown compounds. Therefore, it should be possible to control the physical properties, such as the electronic and magnetic properties and the optical phenomena of octahedral transition metal complexes by modifying the ligand field splitting. PMID:19378561

2009-01-28

437

Theory of melting and crystallization  

Energy Technology Data Exchange (ETDEWEB)

A consistent statistical theory of the crystal-liquid phase transition is developed, being based on a method which takes into account liquidlike fluctuations in crystals and solidlike clusters in liquids. It is shown that degenerate fluidlike droplets have a finite number density at zero temperature, while nondegenerate fluctuations disappear when the temperature goes to zero. The existence of a melting point is proved. This method, which takes into consideration the heterophase fluctuations, provides the possibility of describing metastable states such as a supercooled liquid or an overheated crystal. Conditions for the existence of metastable states are found. The liquid-glass transition can also be described by the method presented here.

1985-07-01

438

The relative X-ray intensity Ksub(#alpha#)/Ksub(#beta#) of 3d elements by photoionization and electron capture  

International Nuclear Information System (INIS)

The measurement of K(alpha)/K(beta) X-ray intensity ratio indicates the excitation process and the chemical state of the atom examined. Theoretical considerations on the origin of this property are presented. The difference of these ratios following photoionization and electron capture are calculated by a computer code generating transition matrix elements. The theoretical assumptions involved in the codes are tested by comparing the experimental and calculated data concerning 3d transition element atoms. (D.Gy.).

1981-03-19

439

Spatial structure of compound dither in L/H transition  

Energy Technology Data Exchange (ETDEWEB)

To study the plasma evolution and spatial structure at the L/H transition, the double hysteresis is examined by use of the 1-dimensional transport model equations. Three mechanisms for the bipolar losses, i.e., the loss cone loss, collisional bulk viscosity loss of ions and the anomalous loss are simultaneously retained. Five-fold multiple bifurcations are found to exist at the plasma edge, similar to the previous 0-dimensional study. Double hysteresis causes a self-generated oscillation, which is attributed to the compound dither, a kind of ELMs. Spatio-temporal evolution of the compound dither is analyzed. (author)

2000-03-01

440

Real-time neutron diffraction study of phase transitions in the Ti-D system after high pressure treatment  

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.

1992-09-01

441

Performance of the transition radiation detector flown on the NMSU/WIZARD TS93 balloon-borne instrument  

Energy Technology Data Exchange (ETDEWEB)

It is built and tested a transition radiation detector (TRD) to discriminate positrons from protons in the balloon flight TS 93 experiment. It is presented the TRD performance using flight data obtaining a proton-positron rejection factor of the order of 10{sup -3}. During the 24 hour flight, the data in the momentum range 4-50 GeV/c are collected. Using the TRD together with the Silicon calorimeter, it is achieved an overall rejection factor of about 10{sup -5} of positron against the proton background over the entire momentum range.

1995-09-01

442

Metallic behavior of Pd atomic clusters  

Energy Technology Data Exchange (ETDEWEB)

We report a study of the nonmetal-metal transition of free-standing Pd{sub N} clusters (2{<=}N{<=}21) carried out through two different theoretical approaches that are extensively employed in electronic structure calculations: a semi-empirical tight-binding (TB) model and an ab initio DFT pseudopotential model. The calculated critical size for the metallic transition decreases rapidly with the temperature and an oscillatory dependence with the cluster size is obtained, particularly in the DFT approach. The TB model describes the metallic behavior for cluster sizes beyond N{approx}12 well. Our obtained critical size at room temperature is of the order of the experimental estimation.

2007-09-12

443

Light Scalar Mesons as Manifestation of Spontaneously Broken Chiral Symmetry  

CERN Document Server

Attention is paid to the production mechanisms of light scalars that reveal their nature. We reveal the chiral shielding of the \\sigma(600) meson. We show that the kaon loop mechanism of the \\phi radiative decays, ratified by experiment, points to the four-quark nature of light scalars. We show also that the light scalars are produced in the two photon collisions via four-quark transitions in contrast to the classic P wave tensor q\\bar q mesons that are produced via two-quark transitions $\\gamma\\gamma\\to q\\bar q$. The history of spontaneous breaking of symmetry in quantum physics is discussed in Appendix.

2010-01-01

444

Isoscalar octupole transition rates in _5_0T, _5_2Cr and _2_0_8Pb from model-independent analyses of 104 MeV #alpha#-particle scattering  

International Nuclear Information System (INIS)

Experimental differential cross sections for 104 MeV #alpha#-particle scattering have been analysed using a method recently proposed for model-independent analyses. Reliable values of isoscalar (0"+ -3"1"-) octupole transition rates in _5_0Ti, _5_2Cr and _2_0_8Pb are presented and compared with electromagnetic rates. (author).

445

Hydrogen flame acceleration and transition to detonation  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the results obtained from two large experimental facilities built at Sandia National Laboratories in Albuquerque, NM. FLAME (Flame Acceleration Measurements and Experiments) is a large horizontal rectangular channel designed to study flame acceleration, transition to detonation, simulation of combustion in containment geometries, component heating, and other problems in hydrogen combustion relevant to reactor safety. The Heated Detonation Tube has been designed to study detonations in hydrogen-air-steam mixtures. Both facilities have been in operation for just over a year. 12 figures.

1984-01-01

446

Hydrogen flame acceleration and transition to detonation  

International Nuclear Information System (INIS)

This paper describes the results obtained from two large experimental facilities built at Sandia National Laboratories in Albuquerque, NM. FLAME (Flame Acceleration Measurements and Experiments) is a large horizontal rectangular channel designed to study flame acceleration, transition to detonation, simulation of combustion in containment geometries, component heating, and other problems in hydrogen combustion relevant to reactor safety. The Heated Detonation Tube has been designed to study detonations in hydrogen-air-steam mixtures. Both facilities have been in operation for just over a year. 12 figures.

1984-10-23

447

Generator coordinate method for triaxial quadrupole collective dynamics in strontium isotopes  

Energy Technology Data Exchange (ETDEWEB)

We discuss the algebraic structure of the generator coordinate method for triaxial quadrupole collective motion. The collective solutions are classified according to the representations of the permutation group of the intrinsic axes. Our method amounts to an approximate angular-momentum projection. We apply it to a study of the spherical-to-deformed-shape transition in light even strontium isotopes {sup 78-88}Sr. We find that triaxial configurations play a significant role in explaining the structure of the transitional isotopes {sup 80-82}Sr. (orig.).

1991-07-29

448

First-principles studies of phase stability and the structural and dynamical properties of metal hydrides. Annual technical progress report, September 15, 1990--May 15, 1991  

Energy Technology Data Exchange (ETDEWEB)

We decided to investigate first the interaction of hydrogen with the 4d transition-metal series, with the first element being hcp Y. Because of the recent development of soft pseudopotentials, we chose to use the plane wave basis set to carry out the calculation. Since problems had been associated with the slow convergence in transition metals, we first tested the computational methods by studying the structural properties of Y; results were encouraging. We started the calculation of YH{sub x} with hydrogen occupying different interstitial sites.

1991-05-15

449

Energy control strategy for a hybrid electric vehicle  

Energy Technology Data Exchange (ETDEWEB)

An energy control strategy (10) for a hybrid electric vehicle that controls an electric motor during bleed and charge modes of operation. The control strategy (10) establishes (12) a value of the power level at which the battery is to be charged. The power level is used to calculate (14) the torque to be commanded to the electric motor. The strategy (10) of the present invention identifies a transition region (22) for the electric motor's operation that is bounded by upper and lower speed limits. According to the present invention, the desired torque is calculated by applying equations to the regions before, during and after the transition region (22), the equations being a function of the power level and the predetermined limits and boundaries.

2002-08-27

450

Effect of grain size and pearlite morphology on the components of the fracture energy in steel 45 in the region of the ductile-brittle transition  

Energy Technology Data Exchange (ETDEWEB)

It is known that in size reduction of the granular structure of ferrite and ferrite-pearlite steels the temperature of the transformation from ductile to brittle condition is lowered. This effect can also be caused by an increase in the dispersity of intragrain and intergrain segregations (sulfides, carbonitrides, and segregations of impurity atoms), which accompanies grain size reduction and promotes initiation and propagation of cracks. In order to clarify the mechanism of fracture of steel in the region of the ductile-brittle transition steel 45 with different grain sizes and pearlite morphologies has been investigated.

1995-11-01

451

EXAFS Study of Semimetal-Semiconductor Transition of Bismuth Clusters  

International Nuclear Information System (INIS)

Extended X-ray absorption fine structure (EXAFS) measurements of bismuth clusters in the temperature range of 23 -300 K have been performed using synchrotron radiation in order to investigate the size dependent phase transition. The inter-atomic distances around 3.0 A and 3.6 A are attributed to the nearest neighbors within the layer and between layers, respectively. EXAFS functions were analysed by the curve fitting method within a symmetric distribution approximation. The nearest neighbor distance of the 0.5 nm thick films is shorter than that of the 300 nm thick films at all the temperatures, which is related to the reduction of the inter-layer correlation.

2007-02-02

452

Duality picture between antiferromagnetism and d-wave superconductivity in t-J model at two dimensions  

Energy Technology Data Exchange (ETDEWEB)

The author shows in this paper an interesting relation between elementary and topological excitations in the antiferromagnetic and d-wave superconducting phases of the t-J model at two dimensions. The topological spin and charge excitations in one phase have the same dynamics as elementary excitations in the other phase, except the appearance of energy gaps. Moreover, the transition from one phase to another can be described as a quantum disordering transition associated with the topological excitations. Based on the above picture, a plausible phase diagram of t-J model is constructed.

2000-02-10

453

Dielectric properties of solid solutions on the base of PbSc_1_/_2Sb_1_/_2O_3 antiferroelectric material  

International Nuclear Information System (INIS)

The results of dielectric measurements in a wide frequency range have been used to find that solid solution samples on the basis of PbSc_1_/_2Sb_1_/_2O_3 have blurred phase transitions. The Curie-Weiss law is performed for different compositions in the temperature range 10-150 K above Curie point. The change of value and sign of the difference between Curie and Curie-Weiss temperatures is connected with the change of phase transition blurring degree.

1988-01-01

454

Dielectric behavior of Ba{sub 0.95}Sr{sub 0.05}TiO{sub 3} ceramics sintered by microwave  

Energy Technology Data Exchange (ETDEWEB)

Here we report detailed dielectric studies carried out on a Barium strontium titanate (BST) (95:5) composition. The material was synthesized by conventional ceramic method and microwave processing, and the later technique resulted in material with high density, improved microstructure and dielectric properties. The dielectric properties were studied as a function of frequency and temperature and well-defined ferroelectric behavior of first order transition was observed. It follows Curie-Weiss law above transition temperature (paraelectric region). Curie temperature is slightly higher for microwave sintered (MS) material.

2002-12-01

455

Determination of the #pi#1g/sub 9/2/ orbit size in "8"8Sr, "9"0Zr, and "9"2Mo from inelastic electron scattering  

International Nuclear Information System (INIS)

A study of the #pi#1g/sub 9/2/ orbit size in "8"8Sr, "9"0Zr, and "9"2Mo is presented. The rms radius for the point-proton density is extracted by studying transitions to 8"+ states in these nuclei. The radii are consistently larger than a value determined in a magnetic electron scattering experiment on "9"3Nb. A qualitative discussion of the ground state occupation of the #pi#1g/sub 9/2/ orbit based on the transition amplitudes to the 8"+ states is given.

456

Completing the Web of $Z_3$ - Quotients of Complete Intersection Calabi-Yau Manifolds  

CERN Document Server

We complete the study of smooth $Z_3$-quotients of complete intersection Calabi-Yau threefolds by discussing the six new manifolds that admit free $Z_3$ actions that were discovered discovered recently by Braun. These manifolds were missed in an earlier work and complete the web of smooth $Z_3$-quotients in a nice way. We discuss the transitions between these manifolds and include also the other manifolds of the web. This leads to the conclusion that the web of $Z_3$-free quotients of complete intersection Calabi-Yau threefolds is connected by conifold transitions.

2010-01-01

457

Changes in the structure and superconducting transition temperature of A-15 compounds under the effect of high pressure and shear strain  

Energy Technology Data Exchange (ETDEWEB)

The study is concerned with the combined effect of high pressure and shear strain on the properties of the A-15 intermetallics Nb3Sn and Nb3Al0.75Ge0.25. The properties discussed are the superconducting transition temperature, the width and intensity of the X-ray diffraction lines, and the width and shape of the Mossbauer absorption lines. It is shown that the combined effect of high pressure and shear strain leads to an intense generation of defects in polycrystalline specimens; the size of the ordered regions does not exceed 300 A even under the least severe conditions. 5 references.

1985-01-01

458

Calculation of the contributions from high-n dielectronic satellites to the K{alpha} resonance line in helium-like iron  

Energy Technology Data Exchange (ETDEWEB)

A simplified relativistic configuration interaction method is used to study the dielectronic satellite transition processes. In this method, the infinite resonant doubly excited states can be calculated, and furthermore, the whole high-n dielectronic satellite transition processes can be treated conveniently by interpolation (rather than extrapolation) in the frame of quantum defect theory. As an example, we calculate the contributions from high-n dielectronic satellites to the K{alpha} resonance line in helium-like iron, and the results are in good agreement with the experimental measurements. (orig.) 39 refs.

1999-02-01

459

Asymmetric rotor model for decoupled bands in transitional odd-mass nuclei  

International Nuclear Information System (INIS)

The high-spin states in transitional odd-mass nuclei are studied in terms of an odd quasi-particle coupled to an asymmetric rotor with a variable moment of inertia (VMI). In order to take into account the VMI, the basis states are expanded in terms of the core eigenfunctions. Excitation energies, quadrupole moments, magnetic moments, B(E2) values and B(M1) values are calculated and compared with the experimental data for nuclei in Au and La regions. On comparison with other descriptions it is found that the treatment with VMI provides a more satisfactory explanation of the data. (Auth.).

460

Application of 10 GeV electron driven x-ray laser in gamma-ray laser research  

Energy Technology Data Exchange (ETDEWEB)

The proposed short wavelength coherent light source driven by the SLAC 3 km linac might be used to induce transitions between nuclear isomeric states. If an isotope were found with energetically adjacent isomeric states, one short-lived and one long-lived, and it were possible to separate and concentrate the long-lived species, and other nuclear and solid-state parameters were favorable, it might be possible to convert sufficient population to the short-lived state to realize [gamma]-ray lasing. Even if the x-ray intensity were insufficient, study of such driven transitions would be quite valuable.

1992-01-01

461

Application of 10 GeV electron driven x-ray laser in gamma-ray laser research  

Energy Technology Data Exchange (ETDEWEB)

The proposed short wavelength coherent light source driven by the SLAC 3 km linac might be used to induce transitions between nuclear isomeric states. If an isotope were found with energetically adjacent isomeric states, one short-lived and one long-lived, and it were possible to separate and concentrate the long-lived species, and other nuclear and solid-state parameters were favorable, it might be possible to convert sufficient population to the short-lived state to realize {gamma}-ray lasing. Even if the x-ray intensity were insufficient, study of such driven transitions would be quite valuable.

1992-12-01

462

Absolute, cascade-free cross sections for the "2S#->#"2P transition in Zn"+ using electron-energy-loss and merged-beams methods  

International Nuclear Information System (INIS)

Absolute, cascade-free excitation cross sections in an ion have been measured for the resonance "2S#->#"2P transition in Zn"+ using electron-energy-loss and merged electron-ion beams methods. Measurements were carried out at electron energies of below threshold to 6 times threshold. Comparisons are made with 2-, 5-, and 15-state close-coupling and distorted-wave theories. There is good agreement between experiment and the 15-state close-coupling cross sections over the energy range of the calculations.

463

Development of plasticity processing of magnesium alloys  

Energy Technology Data Exchange (ETDEWEB)

Recent developments on plastic forming technology of magnesium alloys are presented. Attempts have been undergoing with an aim at forming magnesium alloy parts at lower temperatures. It is believed that fine microstructure magnesium alloys usually have much higher plasticity at lower temperatures and even room temperatures. Extrusion is a method to form magnesium profile products and tube products, which is also one of the effective ways to make fine microstructure magnesium alloys. Superplasticity forming is another method to form high plasticity magnesium alloys. Hot forming of magnesium sheet parts is an important process to form magnesium products. Some developments related to above issues are discussed in the present paper. (orig.)

2003-07-01

464

Metastability and dynamics of the shock-induced phase transition in iron  

Energy Technology Data Exchange (ETDEWEB)

The shock-induced {alpha}(bcc){r_arrow}{var_epsilon}(hcp) transition in iron begins at 13 GPa on the Hugoniot. In the two-phase region above 13 GPa, the Hugoniot lies well above the equilibrium surface defined by G{sub {alpha}}=G{sub {var_epsilon}}, with G the Gibbs free energy. Also, the phase transition relaxation time {tau} is uncertain, with estimates ranging from {lt}50 ns to {approx}180 ns. Here we present an extensive study of these important aspects, metastability and dynamics, of the {alpha}-{var_epsilon} transition in iron. Our primary theoretical tools are (a) accurate theoretically based free energies for {alpha} and {var_epsilon} phases of iron and (b) accurate calculations of the wave evolution following planar impacts. We define metastable surfaces for forward and reverse transitions by the condition that the thermodynamic driving force G{sub {alpha}}{minus}G{sub {var_epsilon}} is just ...

1997-02-01

465

Local-density-functional approach to the isostructural #gamma#-#alpha# transition in cerium using the self-consistent linearized-augmented-plane-wave method  

International Nuclear Information System (INIS)

The isostructural #gamma#-#alpha# phase transition of Ce which occurs at 8 kbar has been studied by means of fully self-consistent (non-muffin-tin potential) linearized-augmented-plane-wave energy band calculations carried out for five different values of the lattice constant. In contradiction to the 4f electron promotional model of the transition, the results yield essentially one 4f electron to be occupied in each phase but with the 4f wave function somewhat less localized, and therefore more bandlike, in the ''collapsed'' #alpha# phase. A singly occupied 4f state is shown to be consistent with the available experimental data. These results strongly support the picture of a 4f localized bold-arrow-left-right itinerant transition at the #gamma#-#alpha# transition and conflict with the promotional model in which some fraction of 4f electrons are transferred to the sd conduction bands. The weaker bonding ...

466

Pneumatic forms for construction of underground structures  

Energy Technology Data Exchange (ETDEWEB)

Discusses design of unconventional pneumatic forms for construction of monolithic liners in mine roadways driven by drilling and blasting. The forms were developed for construction of the municipal subway in Leningrad. They were successfully tested in the Pavlogradugol' mines for construction of chambers situated at shaft bottom at depths of 420 m. The chambers were situated in unstable rock strata. A set of pneumatic forms consisted of 4 to 7 units, each 0.4 m thick and 1.2-2.2 m long. Air pressure was 0.03 MPa, installation time was about 20 min. Service life of pneumatic forms ranged from 3 to 4 years.

1991-08-01

467

Electromagnetic form factors of nucleons with QCD constraints: Systematic study of space- and time-like regions  

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.

2010-04-15

468

Review of high-level waste form properties. [146 bibliographies  

Energy Technology Data Exchange (ETDEWEB)

This report is a review of waste form options for the immobilization of high-level-liquid wastes from the nuclear fuel cycle. This review covers the status of international research and development on waste forms as of May 1979. Although the emphasis in this report is on waste form properties, process parameters are discussed where they may affect final waste form properties. A summary table is provided listing properties of various nuclear waste form options. It is concluded that proposed waste forms have properties falling within a relatively narrow range. In regard to crystalline versus glass waste forms, the conclusion is that either glass of crystalline materials can be shown to have some advantage when a single property is considered; however, at this date no single waste form offers optimum properties over the ...

1980-12-01

469

Gallium-67 activated charcoal: a new method for preparation of radioactive capsules for colonic transit study  

Energy Technology Data Exchange (ETDEWEB)

Indium-111 is currently the radionuclide of choice for colonic transit study. However, it is expensive and not available in many hospitals. Technetium-99m has been proposed for colonic transit study but the short half-life has limited its use. Gallium-67 citrate is inexpensive and available in most countries. Most importantly, it has a suitable half-life for colonic transit study. Attempts have been made in some studies to use {sup 67}Ga citrate to label activated charcoal, but the results have not been good because of poor stability. In this study, we successfully labelled activated charcoal with {sup 67}Ga citrate by adding alcohol and 5% glucose solution. To evaluate the in vitro stability, the {sup 67}Ga-activated charcoal was incubated in a milieu mimicking the intestinal content, containing lipase, trypsin and glycochenodeoxycholate at different pH values (6.0, 7.0, 7.4 and 8.0) and for different durations (0 h, 24 h, ...

2003-06-01

470

New Measurements of the Proton Electromagnetic Form Factor Ratio at Low Q{sup 2}  

Energy Technology Data Exchange (ETDEWEB)

Polarization measurements are allowing the electric to magnetic form factor ratio of the proton to be determined with unprecedented precision. Recent results indicate that there is a large deviation from unity in the proton form factor ratio around Q{sup 2}{approx_equal}0.35 GeV{sup 2}. Furthermore, the deviation from unity is attributed to a deviation of the electric form factor from standard fits and calculations. A new, partially completed, experiment will significantly improve the existing data and will determine the presence, if any, of a narrow structure in the form factor ratio. The new measurement, combined with the expected high precision cross section measurements, will allow the extraction of individual form factors with unprecedented accuracy at low Q{sup 2}.

2009-08-15

471

Extracting Nucleon Strange and Anapole Form Factors from World Data  

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.

2006-09-08

472

Renormalization-group theory of structural phase transitions in A-15 compounds  

Science.gov (United States)

Hamiltonians of Landau-Ginzburg-Wilson type are constructed for order parameters which are bases for certain high-dimensional irreducible or physically irreducible representations in A-15 structure. These are all the representations with wave vectors ?, X, and R and encompass cases of dimension 1, 2, 3, 4, and 6. A renormalization-group analysis was performed on each new distinct Hamiltonian using the Wilson-Fisher "? expansion" method to order ?, in order to determine fixed points and stability, and critical exponents. For representations of R wave-vector symmetry, only the two-dimensional R(1) has a stable fixed point and may produce a second-order phase transition; for all other R wave vector representations, fluctuations prevent second-order transition. No X point representation gives a second-order transition. Representations at ? which are permitted to be second order by "Landau theory" remain so in this analysis. ...

1978-06-01

473

Magnetic moment of the three-quasiparticle state in /sup 177/Ta  

Energy Technology Data Exchange (ETDEWEB)

An experimental investigation was made of the ..gamma..-transitions feeding or de-exciting the 1355 keV isomeric state in /sup 177/Ta. The E2/M1 mixing ratios for the 311 keV interband transition from the isomer and for the 271 keV and the 295 keV intraband transitions within the rotational band on the isomer were determined to be delta = 0.29sup(+0.11)sub(-0.06), 0.25sup(+0.05)sub(-0.03) and 0.30sup(+0.06)sub(-0.08), respectively, employing combined measurements of the linear polarization and angular distribution of the ..gamma..-ray with the aid of conversion electron measurements. Spin and parity assignments of the isomer were confirmed to be 21/2/sup -/. The half-life of the isomer was remeasured to be Tsub(1/2) = 5.0 +- 0.2 ..mu..s and the magnetic moment was found to be ..mu.. = 0.080 +- 0.014 ..mu..sub(N). The gsub(K) and gsub(R) factors for the band on the isomer were deduced separately to be gsub(K=21/2/sup -/) = ...

1982-06-07

474

Magnetic moment of the three-quasiparticle state in "1"7"7Ta  

International Nuclear Information System (INIS)

An experimental investigation was made of the #gamma#-transitions feeding or de-exciting the 1355 keV isomeric state in "1"7"7Ta. The E2/M1 mixing ratios for the 311 keV interband transition from the isomer and for the 271 keV and the 295 keV intraband transitions within the rotational band on the isomer were determined to be delta = 0.29sup(+0.11)sub(-0.06), 0.25sup(+0.05)sub(-0.03) and 0.30sup(+0.06)sub(-0.08), respectively, employing combined measurements of the linear polarization and angular distribution of the #gamma#-ray with the aid of conversion electron measurements. Spin and parity assignments of the isomer were confirmed to be 21/2"-. The half-life of the isomer was remeasured to be Tsub(1/2) = 5.0 +- 0.2 #mu#s and the magnetic moment was found to be #mu# = 0.080 +- 0.014 #mu#sub(N). The gsub(K) and gsub(R) factors for the band on the isomer were deduced separately to be gsub(K=21/2"-) = ...

475

The role of 5-quark components on the nucleon form factors  

Energy Technology Data Exchange (ETDEWEB)

The covariant quark model is shown to allow a phenomenological description of the neutron electric form factor, G{sub E}{sup n}(Q{sup 2}), in the impulse approximation, provided that the wave function contains minor ({approx}3%) admixtures of the lowest energy sea-quark configurations. While that form factor is not very sensitive to whether the q{sup -} in the qqqqq{sup -} component is in the P-state or in the S-state, the calculated nucleon magnetic form factors are much closer to the empirical values in the case of the former configuration. In the case of the electric form factor of the proton, G{sub E}{sup p}(Q{sup 2}) a zero appears in the impulse approximation close to 10 GeV{sup 2}, when the q{sup -} is in the P-state. That configuration, which may be interpreted as a pion loop ('cloud') fluctuation, also leads to a clearly better description of the nucleon magnetic moments. When ...

2007-07-15

476

The Differential Expression of Aqueous Soluble Proteins in Breast Normal and Cancerous Tissues in Relation to Stage and Grade of Patients  

UK PubMed Central (United Kingdom)

Breast cancer is a leading cause of female deaths worldwide. In Malaysia, it is the most common form of female cancer while Infiltrating ductal carcinoma (IDC) is the most common form of breast cancer....Full Text Available

2010-01-01

477

Telephone, mail, and personal questionnaires for data collection. [For heating and cooling  

Energy Technology Data Exchange (ETDEWEB)

Forms used in conducting a national survey about solar energy are presented. Forms for representatives from the domestic, commercial, and industrial sectors, owners and non-owners of solar equipment, are shown. Participants were to be contacted by telephone, mail, and personal visits. (MCW)

1980-02-20

478

Quality assurance requirements for high-level waste form production  

International Nuclear Information System (INIS)

This paper discusses the quality assurance requirements for high-level canistered waste form products which would be acceptable for disposal in a deep geologic repository. A review plan and guidelines are provided.

1989-04-02

479

Primary and secondary structure of the pore-forming peptide of pathogenic Entamoeba histolytica.  

UK PubMed Central (United Kingdom)

A pore-forming peptide is implicated in the potent cytolytic activity of pathogenic Entamoeba histolytica. Using NH2-terminal sequence information of this peptide, the corresponding cDNA was isolated....Full Text Available

1992-10-01

480

Overexpression of bacterial ethylene-forming enzyme gene in Trichoderma reesei enhanced the production of ethylene  

UK PubMed Central (United Kingdom)

In order to efficiently utilize natural cellulose materials to produce ethylene, three expression vectors containing the ethylene-forming enzyme (efe) gene from Pseudomonas...Full Text Available

481

Holographic and Quark-Hadron Duality for Form Factors  

Energy Technology Data Exchange (ETDEWEB)

We study the large-Q{sup 2} behavior of the meson form factor F{sub M} (Q{sup 2}) constructed using the holographic light-front wave functions.

2006-05-15

482

Forming Standing Joint Special Operations Task Force Headquarters.  

Science.gov (United States)

Special Operations Forces (SOF) within a Joint Task Force are controlled by a Joint Special Operations Task Force (JSOTF). Presently, JSOTF headquarters are formed around the core of the Theater Special Operations Command (TSOC), a service SOF headquarter...

2003-01-01

483

Changes in Amide-Linked and Ester Indole-3-Acetic Acid in Cotton Fruiting Forms during Their Development  

UK PubMed Central (United Kingdom)

The concentration of free indoleacetic acid (IAA) is high in cotton (Gossypium hirsutum L.) fruiting forms before anthesis, but is low at and for a few days after anthesis. Amide-linked...Full Text Available

1989-03-01

484

Biological species is the only possible form of existence for higher organisms: the evolutionary meaning of sexual reproduction  

UK PubMed Central (United Kingdom)

Consistent holistic view of sexual species as the highest form of biological existence is presented. The Weismann's idea that sex and recombination provide the variation for the natural...Full Text Available

485

Beam-forming system for electrostatic accelerator  

International Nuclear Information System (INIS)

A simple beam-forming system is described for the electrostatic accelerator of the Scientific-Research Institute of Nuclear Physics of Moscow State University. The system allows the beam to be focused on targets at various distances for a conductor potential of from 1 to 4 MV and beam currents of up to 35 #mu# A.

1988-01-01

486

Adhesion of DOPA-Functionalized Model Membranes to Hard and Soft Surfaces  

UK PubMed Central (United Kingdom)

The adhesive proteins secreted by marine mussels form a natural glue that cures rapidly to form strong and durable bonds in aqueous environments. These mussel adhesive proteins contain an unusual...Full Text Available

2009-01-01

487

A model for the single stranded random coil form of polydeoxyadenylic acid from minimum energy conformations of the dimeric subunit.  

UK PubMed Central (United Kingdom)

The minimum energy conformations of dApdA have been examined for their suitability as buildings blocks of the single stranded coil form of polynucleotides. Calculations of the characteristic ratio C...Full Text Available

1978-09-01

488

A System for the Recording of Clinical Data as an Aid in the Diagnosis of Bovine Digital Disease  

UK PubMed Central (United Kingdom)

A form for the clinical evaluation of bovine digital disease was developed. In this article, each section of the resulting Digit Evaluation Form is discussed and justified. By following the...Full Text Available

1986-08-01

489

A Mouse Model Expressing a Truncated Form of Ameloblastin Exhibits Dental and Junctional Epithelium Defects  

UK PubMed Central (United Kingdom)

SUMMARYAmeloblastin (AMBN) is the second most abundant extracellular matrix protein produced by the epithelial cells called ameloblasts and is found mainly in forming dental enamel....Full Text Available

2009-06-01

491

Studies about oxygen accumulation in palladium silicide formed at Pd/a-Si interface  

International Nuclear Information System (INIS)

... 194 p. auger electron spectroscopy decomposition deposition interfaces oxygen

1986-04-23

492

NASA TECH BRIEF  

Science.gov (United States)

Magnetic Forming Studies. The use of transient high magnetic-field devices has made possible the generation of very large accurately ...

493

Managing the Army National Guard Full-Time Force  

Science.gov (United States)

... Evaluation Report (NCOER). The 360-Degree Assessment will be utilized by the leader/manager in conjunction with the counseling form and ...

2003-02-14

494

Forming Standing Joint Special Operations Task Force ...  

Science.gov (United States)

... THE STANDING JSOTF HEADQUARTERS IN A STANDING JOINT TASK FORCE HEADQUARTERS OR COMBATANT COMMAND ...

2003-04-07

495

Finite Element Analysis of Magnetoelastic Plate Problems.  

Science.gov (United States)

... in the design of such devices as fusion reactors, magnetohydrodynamic generators, magnetically levitated vehicles, magnetic forming devices, and ...

1981-08-01

498

Chiral solitons in nuclei: Electromagnetic form factors  

Science.gov (United States)

We calculate the electromagnetic form factors of a bound proton. The chiral quark-soliton model provides the quark and antiquark substructure of the proton, which is embedded in nuclear matter. This procedure yields significant modifications of the form factors in the nuclear environment. The sea quarks are almost completely unaffected, and serve to mitigate the valence quark effect. In particular, the ratio of the isoscalar electric to the isovector magnetic form factor decreases by 20% at Q{sup 2}=1 GeV{sup 2} at nuclear density, and we do not see a strong enhancement of the magnetic moment.

2004-12-01

499

BIOMAGNETIC RESPONSE OF SIMPLE BIOLOGICAL ...  

Science.gov (United States)

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

1970-01-01

500

A NEW FORM OF SOLID STATE SOLAR GENERATOR  

Science.gov (United States)

... nent to the design and construction of metal-semiconductor solar cells, in that both the photovoltage and the efficiency of metal-semiconductor cells ...

1962-01-01