bluuebunny/crossref_metadata_2025_split huggingface dataset:
Small Angle Neutron Scattering with Hydrogenated Amorphous Cu50 Ti50 and Ni-Ti-Si Alloys
Authors: Lamparter P. , Boucher B. 
Published: February 2015

Abstract
The metallic glasses Cu50Ti50, Ni30Ti60Si10, Ni32Ti52Si16 , Ni16Ti68Si16 and Ti84Si16 were produced by melt spinning. The alloys in the blank state as well as after loading with hydrogen or deuterium were investigated by small angle neutron (SANS) and X-ray (SAXS) scattering. The scattering of the different amorphous alloys exhibited common features. SANS follows a power-law with exponent of the scattering vector between -3 and -4. The melt-spun glasses contain extended structural inhomogeneities which are associated rather with the local composition than with the local density. SAXS measurements did not show effects above the background level.
Loading the alloys with hydrogen or deuterium causes strong effects in the SANS behaviour. From the results it is concluded that the amorphous alloys contain inner surfaces where the hydrogen atoms segregate.
The Microwave Spectrum of 2,6-Lutidine, Analysis of Internal Rotation and 14 N Hyperfine Structure
Authors: Thomsen C. , Dreizler H. 
Published: February 2015

Abstract
The rotational spectrum of 2,6-lutidine, (CH3)2C5H3N, has been recorded between 6 and 26.5 GHz using pulsed molecular beam microwave Fourier transform spectroscopy. The rotational constants are A = 3509.7139(84) MHz, B = 1906.8639(101) MHz, and C = 1254.6215(14) MHz, the barrier to internal rotation of the two methyl groups is V3 = 1.1752 kJ/mol, their moments of inertia were found to be Iα = 3.0808(9) uÅ2 . The nitrogen nuclear quadrupole constants are χaa = +1.600(5) MHz, χbb = -4.572(3) MHz and χcc = +2.972(5) MHz.
The Microwave Spectrum of the Thiophene-Argon van der Waals Complex
Authors: Kretschmer U. , Stahl W. , Dreizler H. 
Published: February 2015

Abstract
The rotational spectra of the 32S-and 34S-thiophene-argon complex have been studied in the microwave region between 6 and 18 GHz using a pulsed molecular beam Fourier transform micro-wave spectrometer. The rotational and centrifugal distortion constants of the 32S-thiophene-argon complex were found to be A = 3280.38865(15) MHz, B = 1203.32018(15) MHz, C = 1123.45120(11) MHz, ΔJ = 3.3311 (33) kHz, ΔJK = 16.9015(31) kHz, ΔK = -18.302(14) kHz, δj = 0.235074(86) kHz, δK = 4.340(33) kHz. For the 34S-isotopomer A = 3231.16878(15) MHz, B = 1194.05602(58) MHz and C = 1109.53497(30) MHz with almost the same centrifugal distortion constants were obtained. The argon atom is placed 3.59 Å above the ring plane.
High Resolution IR-Spectra of Furane and Thiophene
Authors: Pankoke B. , Yamada K. M. T. , Winnewisser G. 
Published: February 2015

Åbstract
The spectra of the out-of-plane fundamental band of furane (C4H4O) centered at 744 cm -1 and of thiophene (C4H4S) at 712 cm -1 were measured in Doppler-limited resolution with a diode-laser spectrometer at Köln and with a high-resolution Fourier transform spectrometer at the University of Gießen. An interactive Loomis-Wood program was applied to identify the c-type transitions of furane and thiophene. The molecular parameters were determined from the observed line positions and the available microwave data by least-squares-fits using Watson's A-reduced Hamiltonian. Some relations among parameters appearing in different formulations of the Hamiltonian are represented explicitly in connection with the derivation of the unreduced constants. The unreduced constants were derived for both molecules using the planarity relations. We determined the inertial defects to be ≈ 0.05 amuÅ 2 in the ground state and ≈ -0.2 amuÅ 2 in the excited state for both furane and thiophene.
On the Parameter Plane of Nonlinear Coupled Oscillators
Authors: Metzler Wolfgang , Brelle Achim , Schmidt Klaus-Dieter , Danker Gerrit , Köppe Matthias , Mahrenholz Daniel 
Published: February 2015

Abstract
Two well-known bifurcation routes to chaos of two-dimensional coupled logistic maps are embedded in a two-parameter plane of a canonical nonlinear oscillator which contains a non-analytic analogon to the Mandelbrot set.
Three Types of Chaotic Attractors in 3 D Maps
Authors: Klein Michael , Kittel Achim , Baier Gerold 
Published: February 2015

Abstract
Coupling a one-dimensional chaotic forcing to a stable fixed point in the plane may generate different fractal attractors embedded in three dimensions. The system with real eigenvalues of the fixed point gives rise to simple chaotic attractors with three different types of fractal structures. We show that the competition of local exponents provides a generic criterion for the classification of the fractal structures in dynamical systems.
Iterated Differentiable Maps with Nowhere Differentiable Basin Boundaries
Authors: Metzler Wolfgang 
Published: February 2015

Abstract
The fractal basin boundary of a two-dimensional discrete dynamical system modelling a chaotic forcing applied to bistability is shown to be identical to the graph of an infinite series F(x,t)=

of weighted iterates of an ergodic unimodal interval function f. In the special case, when f is the logistic map in "full chaos", i.e. ƒ: x ↦ 4x(1 - x), F is a nowhere differentiable function of x for each t > exp(-λf) (even equal to the Weierstrass function), where λf >0 is denoting the Lyapunov exponent of f. For further chaotic functions f, nowhere-differentiability is shown to be obvious from computer simulations.
High-Resolution Vibrational Spectra of Furazan IV. The Aj Fundamental v2 at ~ 1418 cm-1 from Fourier-Transform Infrared Spectroscopy
Authors: Stiefvater Otto L. , Klee Stefan 
Published: February 2015

Abstract
The band origin of the A1 mode v2 , which represents the symmetrical stretching vibration of the two C = N bonds of furazan, has been determined from the high-resolution FT-IR band as v2
0 = 1418.4724± 0.0001 cm-1. The rotational parameters of this excited state, as determined in a preceding DRM microwave study, have been confirmed and their precision was raised through the combined fit of microwave data and of some 2500 rovibrational transitions.
The use of conjugate low-J Q-branch lines for the determination of the origin of a B-type IR band of an asymmetric rotor is illustrated.
Rayleigh-Taylor Instability of a Compressible Plasma with Finite Larmor Radius Effects
Authors: Ariel P. D. 
Published: February 2015

Abstract
The Rayleigh-Taylor instability of a compressible plasma in the presence of a horizontal magnetic field is investigated, taking into account the effects of finite Larmor radius. Only transverse perturbations are considered. The problem is shown to be characterized by a variational principle. Using it, the dispersion relation is obtained for a plasma layer of finite thickness and having an exponentially varying density. It is found that the finite Larmor radius effects can thoroughly stabilize unstable configurations. For configurations which are not completely stabilized, the compressibility stabilizes some of the disturbances which are unstable for an incompressible plasma.
Particles and Charges in the Vortex Sponge
Authors: Dmitriyev Valery P. 
Published: February 2015

Abstract
The vortex sponge, which postulates a steady state of vortex turbulence in an ideal fluid, is a substratum invented to explicate parsimoniously "action at a distance" and especially vacuum electromagnetics.
A disturbance of the vortex sponge's structural elements is shown to behave like a Schrödinger quantum particle. Vorticity reversal points model elementary electrical charges.
Molecular Motion in Solid Tetraethyl-and Tetrabutylammonium Perchlorates
Authors: Szafrańska Barbara , Pająk Zdzisław 
Published: February 2015

Abstract
The proton NMR second moment and spin-lattice relaxation time for polycrystalline tetraethyl-and tetrabutylammonium perchlorates have been measured over a wide range of temperatures. Solid-solid phase transitions related to the onset of cation tumbling were found for both compounds and confirmed by DSC. In the low temperature phases methyl-group reorientation was evidenced. For tetrabutylammonium cation a dynamic nonequivalence of one methyl group is found. The geared motion of the alkyl chains related with the onset of successive CH2-group reorientations is suggested.
The Bond N -Cl. A Spectroscopic (35Cl-NQR, IR) Investigation
Authors: Gowda B. Thimme , Weiss Alarich 
Published: February 2015

Abstract
Chlorine bound to nitrogen is an interesting oxidizing agent in aqueous, partial aqueous and non-aqueous media. One can assume that the oxidizing action of the chlorine depends on the polarization of the Cl atom in the bond N -Cl which will depend on the electron distribution in the ligands R and R″ of the configuration R -NCl -CO -R″. 17 compounds were synthesized with R = substituted phenyl radical C6H5-y Xy, X = Cl, NO2, R″ = CH2Cl. The 35Cl NQR frequencies are observed in the range 52 to 54 MHz (T = 77 K) for the Cl(N) 34 to 37 MHz for the phenyl chlorines and the CH2Cl group. Their temperature dependence was followed up to 300 K. Therefrom the assignment of the resonance to certain Cl-atoms in the molecules is possible. Generally, the substitution of a negative substituent X (Cl, NO2) in the phenyl ring raises the resonance frequencies; the influence of the CH2Cl group on the N -Cl bond is weak. Strong is the influence of the carbonyl group on the N -C l bond. The IR group frequencies ν(C = O) are found in the range 1680 ≤ ν (C = O)/ cm−1≤ 1717, shifted up by ≤ 20 cm−1 compared to the corresponding acetamide R ⎯ NH ⎯CO ⎯ R″. Influence of the phenyl ring substitution on ν (C = O) does not follow a simple law of inductive effect. Also a correlation between the vibration frequencies of the N ⎯ Cl group and the phenyl group substitution is not found.
Semiempirische Rechnungen zur Bestimmung der Konformation des 4,5-Dihydro-1,3-dioxepins und seines 2-Methyl-Derivats
Authors: Esser Josef , Fleischhauer Jörg , Frauenrath Herbert , Jansen Christoph , Kramer Bernd , Runsink Jan 
Published: February 2015

Abstract
Semiempirical Calculations for the Determination of the Conformation of 4,5-dihydro-1,3-dioxepine and its 2-methyl derivative
The possible conformations of the title compounds have been studied with the semiempirical methods MNDO and AM1. In the local minima, the vibration frequencies have been calculated to get the free enthalpy of each conformer and its equilibrium concentration. The energy minimized structures and the calculated thermodynamical values are compared with experimental results. From our investigations we conclude that the chair conformation is preferred. In the case of the methyl derivative, the substituent favours the equatorial position.
Structural Features for Non-Existence of Conjugated Patterns for Carbocyclic and Heterocyclic Compounds
Authors: Morikawa Tetsuo 
Published: February 2015

Abstract
At least one polygonal arc (a′ a a′), where (a′) and (a) denote unconjugated and conjugated vertices (connected with two vertices), respectively, is involved implicitly and/or explicitly in a skeleton of carbocyclic and heterocyclic compounds with no side-chains, if the number of conjugated vertices is even, and if there is no conjugated structure. This case is discussed in detail.
Delayed Feedback Control of Chaos in an Electronic Double-Scroll Oscillator
Authors: Kittel A. , Parisi J. , Pyragas K. , Richter R. 
Published: February 2015

Abstract
We present experimental results on stabilizing unstable periodic orbits of an autonomous chaos oscillator based on a simple electronic circuit. Control is achieved by applying the difference between the actual and a delayed output signal of the oscillator. The quality of chaos control can be measured via the strength of perturbation. The dependence on the delay time shows a characteristic resonance-type behavior.
Nonequilibrium Phase Transition and Current Filaments in Extrinsic Semiconductors
Authors: Christen Thomas 
Published: February 2015

Abstract
A phenomenological model for charge transport in extrinsic semiconductors is presented. For shallow impurities, large saturated impact-ionization coefficient and sufficiently low lattice temper­ature, the current-field characteristic is S-shaped (SNDC) due to the interplay between impact ionization and scattering of carriers from acoustic phonons, ionized and neutral impurities. The present model provides and explanation of the experimentally observed disappearance of SNDC above a critical lattice temperature. In the region of negative differential conductivity where a current-controlled uniform state is unstable, current filaments are calculated numerically.
Automatically Tuned Probe Head System for Pulsed NQR Spectroscopy in Extreme Thermodynamic Conditions
Authors: Ostafin Michał , Maćkowiak Mariusz , Bojarski Marek 
Published: February 2015

Abstract
A complete N Q R probe-head system operating in the frequency ranges 0.5 -150 and 150- 300 MHz is described. The head is particularly suited for NQR experiments carried out at a remote location, for example in a low-temperature cryostat or high-pressure chamber. Moreover, the head system includes a microprocessor-controller for automated tuning of the probe to the operating frequency of the associated NQR spectrometer. The controller can be easily interfaced to a PC via standard serial port.
Quadrupole Coupling in some H-bonded Organic Systems by ab initio Lattice Calculations of Electric Field Gradients
Authors: Palmer Michael H. , Blair-Fish John A. 
Published: February 2015

Abstract
We present ab initio Hartree-Fock lattice calculations performed in the unit cell environment, to compute a wave-function and the derived electric field gradients for the bulk material. These calculations differ from cluster calculations by including the effects of more distant neighbour molecules. Examples considered are ammonia, formamide, oxamide, urea, thiourea, uracil, para-banic acid, alloxan, guanidine bicarbonate and melamine.
81Br NQR for Uncoordinated Br ions in trans-[CoBr2(en)2][H5O2]Br2 and trans-[CoBr2(en)2] [D5O2]Br2
Authors: Honda H. , Sasane A. , Miyagi K. , Ishikawa A. , Mori Y. 
Published: February 2015

Abstract
The temperature dependence of the 81Br NQR frequencies (vD) for uncoordinated Br- ions in trans-[CoBr2(en)2] [D5O2]Br2(D) has been determined by a continuous-wave spectrometer. vD amounted to 16.200 MHz at 273 K. This is lower by 418 kHz than the 81Br NQR frequency (vH) for trans-[CoBr2 (en2] [H5O2 ]Br2 (H). The frequency difference (Δv = vH -vD) remained almost constant in the temperature range studied. A shortening of the O-H bond length caused by deuteration could explain the magnitude and the sign of Av on the basis of a point charge model calculation. The compounds D and H yielded 81Br NQR lines in the range 110-320 K and 90-343 K, respectively. As to the 59Co NQR frequencies (7/2 - 5/2), the observed isotope frequency shifts (Δv1 = v1H - v1D) between D and H were smaller than 5 kHz. Below 160 K, 59Co resonances were only available by pulsed experiments. 59Co NQR spin-lattice relaxation times T1Q of 0.54 ms at 194 K and 4.8 s at 77 K for H have been observed.
Structural Phase Transition of N,N-Dimethylnitramine as Studied by 14N Nuclear Quadrupole Resonance
Authors: Asaji Tetsuo , Tomizawa Hideshi , Ikeda Ryuichi 
Published: February 2015

Abstract
The 14N nuclear quadrupole relaxation time and resonance frequencies v+, v-, and vd of N,N-dimethylnitramine were measured between 14 and 313 K. The frequency increase of v+ and v- observed below Tc (108 K) is explained by the increase of p π electrons in the amino nitrogen caused by the deformation of the molecular skelton, which is planar above Tc. The sharp T1Q minima for v+ and v- observed at Tc are attributed to the softening of vibration modes on both sides of Tc. The fluctuation o f the nitrogen-hydrogen magnetic dipolar interaction due to CH3 reorientation was detected as a broad T1Q minimum observed around 84 K. A logarithmic divergence of T1Q
-1 observed on the high-temperature side of Tc suggests the presence of a diffusive or overdamped-type soft mode.
Low Temperature Isotope Effect in Ammonium Hexachloroselenate(IV) Studied by 35Cl NQR
Authors: Kume Y. , Asaji T. , Ikeda R. 
Published: February 2015

Abstract
The temperature dependence o f the 35Cl NQR frequency and spin-lattice relaxation time T1Q of (NH4)2SeCl6 and (ND4)2SeCl6 were measured from 400 K to 24.8 and 53.8 K, respectively. The disappearance of NQR signals in the low temperature region of both salts is attributed to phase transitions. We concluded from the temperature behavior of just above the transition point that the operative mechanism o f the transition is different in these salts: The transition of (ND4)2SeCl6 seems to be associated with rotary soft modes, while in the natural salt non-rotary soft modes seem to play an important role at the transition.
Materials Characterisation by Nuclear Quadrupole Interaction
Authors: Bastow T.J. 
Published: February 2015

Abstract
The power of solid state NMR to characterise solids by determining the nuclear quadrupole coupling of the constituent nuclei is demonstrated for a number of com pounds of current interest in a materials science laboratory. Recent results are presented for the nuclei 17O , 23Na, 27Al, 39K, 71Ga, 91Zr, 93Nb, and 139La. These were derived using a variety of FT NMR techniques including static, magic angle spinning and frequency stepped spin echo NMR spectroscopy.
Why is the Cu(2) Asymmetry Parameter of NQR Spectra in HTSC so Small?
Authors: Eremin M. V. 
Published: February 2015

Abstract
An explanation has been proposed for the unusual behaviour of the asymmetry parameter of NQR spectra of Cu(2) in layered cuprates. When holes are introduced into the plane, Zhang-Rice singlets (ZRS) appear which have a strong vibronic coupling to tetragonal and orthorhombic modes. The equation for the adiabatic potential has been derived. It is shown that its minimum, correspond­ ing to orthorhombic distortions of the oxygen plaquette around the Cu(2) ions, changes under doping to tetragonal character due to the singlet exchange coupling between copper and oxygen holes. A strong interaction of ZRS via the phonon field has been found.
Calculated Spin-lattice Relaxation of 103Ru Compared with Low Temperature Quadrupole Orientation Measurements
Authors: Markendorf R. 
Published: February 2015

Abstract
The spin-lattice relaxation time T1 in 103Ru has been determined on the basis of the Dirac theory and strict relativistic band structure calculations. The low temperature relaxation time T(of 103Ru in an axially symmetric quadrupole field and the quadrupole moment Q have been measured by Green and Stone using the technique of low temperature quadrupole orientation. For the usual reference value T1 T, which corresponds to relaxation in a Zeeman spectrum, they obtain 39(6) sK, which exceeds our value by 134%. This large discrepancy is attributed to the fact that the spin relaxation by direct quadrupole scattering of conduction electrons, the so-called Mitchell contribution, is dominant. According to our calculations it amounts to 81% of the total relaxation rate. This contribution could not be included in the evaluation of the experimental data.
Quadrupole Interaction at Surfaces -Nuclear Methods
Authors: Haas H. 
Published: February 2015

Abstract
The measurement of the electric quadrupole interaction with nuclear techniques allows the study of monolayer coverages or even isolated atoms at surfaces and interfaces due to the inherent sensitivity of these methods. Recently electric field gradients at surface atoms have been investigated with Mößbauer Spectroscopy, Polarized Beam NMR , and Perturbed Angular Correlation (PAC).
The highly sensitive PAC technique with 111In and 111mCd sources, in particular, has been applied to several metal and semiconductor surfaces. The use of flat as well as stepped surfaces has allowed the assignment of the measured quadrupole interaction frequencies to specific surface sites. For the Pd(111) surface a particularly complete description is possible, since for five different sites (terrace adatoms, ledge adatoms, kink adatoms, ledge and terrace atoms) the field gradients and their orientation could be determined. They represent a challenging problem for understanding the electronic structure of metallic surfaces. Through the study of the temperature dependence of the different components the diffusion of the radioactive probe atoms can be followed.
The data from 57Fe Mößbauer spectroscopy on iron surfaces with monolayer coverage and NMR surface studies of 7Li and 23Na at high temperatures are reviewed.
An outlook for further developments of the nuclear techniques is presented, particularly in view of the variety of radioactive isotope beams available from on-line isotope separators like the ISOLDE facility at CERN.
Rayleigh-Taylor Instability of Newtonian and Oldroydian Viscoelastic Fluids in Porous Medium
Authors: Sharma R. C. , Bhardwaj V. K. 
Published: February 2015

Abstract
The Rayleigh-Taylor instability of viscous and viscoelastic (Oldroydian) fluids, separately, has been considered in porous medium. Two uniform fluids separated by a horizontal boundary and the case of exponentially varying density have been considered in both viscous and viscoelastic fluids. The effective interfacial tension succeeds in stabilizing perturbations of certain wave numbers (small wavelength perturbations) which were unstable in the absence of effective interfacial tension, for unstable configuration/stratification.
Investigation of the Zero-Field Splitting of d8 Ions in Pseudo-tetragonal Ni(II) Compounds
Authors: Chen Jia-Jun , Du Mao-Lu , Li Zhao-Ming 
Published: February 2015

Abstract
This paper presents a cluster approach to the zero-field splitting (ZFS) of the ground state 3A2(F) of d8 ions with tetragonal symmetry, in which not only the spin-orbit coupling of the central transition-metal-ion but also that of ligands contributes. For some pseudo-tetragonal Ni(II) com­ pounds the calculated values of the ZFS parameter follow the order Cl-> Br-> I-. This agrees with the experimental finding, while the pure crystal field approach considering only the coupling of central metal ion yields the opposite trend.
14N Quadrupole Relaxation of DMF and DMF-d7 in DMSO at Infinite Dilution
Authors: Mao Xi-an , Holz Manfred 
Published: February 2015

Abstract
The 14N quadrupole relaxation time in pure DMF is by 9% longer than in pure DMF-d7, showing the dependence of the reorientational molecular motion on the square root of the moment of inertia. But for traces of DMF and DMF-d7 in DMSO, the 14N quadrupole relaxation time tends to obey the "square-root-of-the-reduced-mass law", as expected from the kinetic theory of dense fluids. The vanishing of the moment-of-inertia effect on the intramolecular nuclear quadrupole relaxation is discussed in terms of molecular translation-rotation coupling.
Reanalysis of the Nuclear Quadrupole Coupling in the Rotational Spectrum of N-Methylpyrrole
Authors: Huber S. R. , Bauder A. 
Published: February 2015

Abstract
The rotational spectrum of N-methylpyrrole has been measured with pulsed nozzle Fourier transform microwave spectrometers between 6 and 38 GHz. The quadrupole hyperfine structure due to 14N has been reanalyzed in the A (m = 0) state o f the methyl internal rotation. Improved rotational constants, centrifugal distortion constants, and quadrupole coupling constants have been simultaneously determined from the measured transition frequencies in an iterative least-squares fit.