bluuebunny/crossref_metadata_2025_split huggingface dataset:
Copper Contamination Mechanism of Silicon Substrates from HF Solutions
Authors: Bertagna Valérie , Rouelle François , Chemla Marius 
Published: February 2015

The contamination of silicon wafers from dilute HF solutions containing ultratrace levels of metallic ion impurities is a subject of constant interest. The mechanism of copper electroless deposition from HF onto monocrystalline silicon was investigated using a new electrochemical cell, which proved to be a very sensitive detector for in situ characterization of silicon surfaces.
Upon addition of copper trace amounts, the open-circuit potential was observed to shift rapidly towards more positive values at a rate nearly proportional to the copper concentration. All potential/ time curves tend to reach a limiting value of the potential, while quantitative measurements of radioactive tracers revealed that during a few tens of minutes, copper ions were continuously reduced on the silicon surface.
Electrochemical potentials and voltammetric measurements were interpreted in terms of the mixed potential theory and led to the conclusion that copper nuclei act as a catalyst which enhances the cathodic activity for protons reduction. The model was supported by AFM observations which demonstrated the initiation of corrosion pits around the nuclei.
Differential Thermal Analysis and PVT Measurements on 2,2,2-Trichloro-ethanol Under High Pressure
Authors: Jenau M. , Sandmann M. , Würflinger A. , Tamarit J. Ll. 
Published: February 2015

Abstract
The phase behaviour, the calorimetric and volumetric properties of 2,2,2-trichloro-ethanol (TCE) have been studied with differential thermal analysis (DTA) and pVT measurements in the pressure range 1 atm to 300 MPa and temperatures between 250 K to 355 K. TCE displays a metastable plastic phase (solid I') and a non-plastic solid phase II at atmospheric pressure. At least two pressure-induced solid phases have been detected: a stable plastic phase (solid I') and a non-plastic phase (solid III). There are two sets of triple points: a) 123 MPa and 308 K with the phases solid I, solid II and the liquid, b) 243 MPa and 316 K for solid I, II, III. Furthermore a metastable low-temperature brittle form (solid II') has been found, which transforms to solid I at a considerably lower temperature than solid II. The melting curve of solid I' can be pursued to higher pressures up to 260 MPa. On the other hand, the melting curve of the stable plastic phase solid I can be extrapolated beyond the triple point to pressures below 123 MPa. Volume and enthalpy changes are reported for all phase transitions.
Ionic Motion of Phenethylammonium Ion in [C6H5CH2CH2NH3]2 PbX4 (X = Cl, Br, I) as Studied by 1 H NMR
Authors: Ueda Takahiro , Omo Mariko , Shimizu Katsuyuki , Ohki Hiroshi , Okuda Tsutomu 
Published: February 2015

Abstract
The temperature dependences at 110 to 400 K of the : 1H spin-lattice relaxation time (7\) of the phenethylammonium ion in phenethylammonium lead(II) halides, [C6H5CH2CH2NH3]2PbX4 (X = Cl, Br, I), revealed that this ion shows reorientation of the NH3 moiety around the three-fold axis and torsional motion of the alkyl chain (CH2CH2). Below room temperature, the chloride and the bromide yielded two minima of 1H T1 originating from NH3 reorientation, whereas the iodide yielded only one minimum. These findings indicate that there are two kinds of NH3 sites in the chloride and bromide but only one in the iodide. The T1 minimum observed below room temperature gave similar activation energies of the NH3 reorientation, Ea = 15.7,15.1 and 15.5 kJ mol 1 for the chloride, bromide and iodide, respectively, suggesting that the corresponding NH3 groups are located at similar environments. Above room temperature, the T1 minimum in the chloride and bromide gave larger Ea values of the NH3 reorientation: Ea - 23.6 and 20.2 kJ mol-1 for the chloride and bromide, respectively. These findings suggest that the NH3 groups form stronger hydrogen bonding with halogen atoms (N-H ... X). Furthermore, the amplitude of the CH2CH2 motion is discussed, using the two sites jump model. The activation energies for the CH2CH2 motion in these compounds are almost equal (Ea = 29.1, 30.0 and 28.2 kJ mol -1 for the chloride, bromide and iodide, respectively), but that the torsional angles become larger in the order iodide ⪡ bromide<chloride.
Chaotic Spike Patterns Evoked by Periodic Inhibition of Rat Cortical Neurons
Authors: Schindler K. A. , Bernasconi C. A. , Stoop R. , Goodman P. H. , Douglas R. J. 
Published: February 2015

Abstract
We use methods of nonlinear dynamics to describe the effect of periodic inhibition on the patterns of action potentials generated by regular spiking rat cortical neuron in vitro. Both direct measurements and our mathematical model reveal that chaotic patterns of discharge can be evoked at certain frequencies of inhibitory stimulation. We use detailed biophysical simulation of a cortical neuron to explain the firing patterns in terms of known membrane ionic conductances.
The Complete Bifurcation Diagram for the Logistic Map
Authors: Tsuchiya Takashi , Yamagishi Daisuke 
Published: February 2015

Abstract
The complete bifurcation diagram as well as the basin of attraction for the logistic map is presented for the whole range of the control parameters, namely -2≤a≤4 where the system remains finite. Equivalence of the newly found bifurcation branch to the conventional branch is shown.
X-ray Diffraction Studies on Supercooled Aqueous Lithium Bromide and Lithium Iodide Solutions
Authors: Takamuku Toshiyuki , Yamagami Motoyuki , Wakita Hisanobu , Yamaguchi Toshio 
Published: February 2015

Abstract
X-ray diffraction measurements were performed on liquid LiBr • 5H2O and Lil • 5H2O at temperatures from -30 to 25 °C. The total radial distribution functions did show that on supercooling the hydration shell of the halide ions becomes more structured, while that of the lithium ions becomes distorted. The larger the halide ion, the stronger becomes the water-water interaction around halide ions with lowering temperature. However, the distance between the water molecules in the hydration shells of the halide ions depends little on their size. On the basis of the present results, together with those of our previous investigation on LiCl • 5H2O at temperatures from - 135 to 100°C, the effects of temperature and the size of the halide ions on the structure of the solution are discussed.
Hydromagnetic Stability of Two Rivlin-Ericksen Elastico-Viscous Superposed Conducting Fluids
Authors: Sharma R. C. , Kumar P. 
Published: February 2015

Abstract
The stability of the plane interface separating two Rivlin-Ericksen elastico-viscous superposed fluids of uniform densities when the whole system is immersed in a uniform horizontal magnetic field has been studied. The stability analysis has been carried out, for mathematical simplicity, for two highly viscous fluids of equal kinematic viscosities and equal kinematic viscoelasticities. It is found that the stability criterion is independent of the effects of viscosity and viscoelasticity and is dependent on the orientation and magnitude of the magnetic field. The magnetic field is found to stabilize a certain wave-number range of the unstable configuration. The behaviour of growth rates with respect to kinematic viscosity and kinematic viscoelasticity parameters are examined numerically.
Linear and Non-linear Polarizabilities for P2(X1Σg
+)
Authors: Maroulis George 
Published: February 2015

Abstract
Electric polarizabilities and hyperpolarizabilities were calculated from accurate self-consistent field wavefunctions for P2. The following values are reported, using the experimental bond length of 1.8934 Å: dipole polarizability αzz = 69.83 and αxx = 41.20 e2 a0
2 Eh-1 , second dipole hyperpolarizability γzzzz = 17 040, γxxxx= 11 581 and γxxzz = 4724 e4a0
4Eh
-3, quadrupole polarizability, Czz „zz = 276.14, Cxz,xz = 232.64 and Cxx,xx = 151.25 e2 a0
4Eh
-1 , dipole-octopole polarizability, Ez,zzz, = 331.00 and Ex,xxx = -154.66 e2 a0
4Eh
-1 and for the dipole-dipole-quadrupole hyperpolarizability, Bzz,zz = - 2441, Bxz,xz = - 1442, Bxx,zz = 866 and Bxx,xx = - 1411 e3a0
4Eh-2.
On the Correspondence of Time-Delay and Spatially Extended Systems
Authors: Bünner M. J. , Meyer Th. , Kittel A. , Par J. 
Published: February 2015

Abstract
We establish a straightforward connection between spatially extended systems, the dynamics of which are modeled with the help of partial differential equations and time-delay systems. To this end, we give a linear partial differential equation with a nonlinear boundary condition whose solutions are equivalent to the solutions of a time-delay differential equation. We observe that the phase space of these systems exhibits a pronounced structure. In this paper, we express the structure of the phase space of time-delay systems and the corresponding spatially extended system by distinguishing between a ‘linear subsystem’ and a ‘localized nonlinearity’. We find that the high-dimensional chaotic dynamics observed in time-delay systems is fundamentally different from the spatio-temporal chaos observed in homogeneous spatially extended systems, the dynamics of which is modeled with the help of nonlinear partial differential equations. To this end, we investigate the space-time correlation function and the ‘thermodynamic limit’.
Space-Discretized Verlet-Algorithm from a Variational Principle
Authors: Nadler Walter , Diebner Hans H. , Rössler Otto E. 
Published: February 2015

Abstract
A form of the Verlet-algorithm for the integration of Newton’s equations of motion is derived from Hamilton's principle in discretized space and time. It allows the computation of exactly time-reversible trajectories on a digital computer, offers the possibility of systematically investigating the effects of space discretization, and provides a criterion as to when a trajectory ceases to be physical.
Scaling Properties of Traffic-flow Data
Authors: Wagner Peter , Peinke Joachim 
Published: February 2015

Abstract
By computing the probability distributions of the velocity difference between cars a time-delay τ apart, the scaling properties of traffic flow can be analysed. These data display scaling behaviour thus confirming earlier results that have found 1/ fα -noise in traffic flow. Furthermore, the applicability of the scaling analysis for describing the two-point statistics of traffic flow is demonstrated, leading to an additional test for the dynamical properties of microscopic and macroscopic traffic flow models.
Combined High Resolution UV and Microwave Results: Structure of the Benzonitrile•Water Complex
Authors: Helm R. M. , Vogel H.-P. , Neusser H. J. , Storm V. , Consalvo D. , Dreizler H. 
Published: February 2015

Abstract
High resolution ultraviolet (UV) and molecular beam Fourier transform microwave (MB FTMW) spectroscopy of the benzonitrile·water (BZNW) cluster were performed to measure cluster structures in the S0 and S1 states. The MW experiments provide additional information on the structure and the 14N-nuclear quadrupole coupling in the ground state So, the UV experiments on the dynamics in Si. The rotationally resolved sub-Doppler UV spectra of BZNW were measured by mass-selective resonance-enhanced two-photon ionization. For the first time this UV technique has been applied to hydrogen-bonded clusters. From the UV spectra the rotational constants are obtained by Correlation Automated Rotational Fitting. The MW spectra were analyzed with the model of a centrifugally distorted rotor including nuclear quadrupole coupling. A r0 -fit of the water position within the cluster is performed. The water is found to be located with its oxygen nearly in the plane of benzonitrile (BZN). For S0 (S1), the distance of the oxygen to the ortho hydrogen is r0 = 2.477(4) Å (2.457(2) Å) and the angle to the ortho carbon-hydrogen bond 143.34(2)° (141.91(3)°). The structure differences in S1 and S0 can be explained by the structure changes of the BZN molecule. A line broadening, which points to a faster decay in Si upon clustering with the polar solvent, is observed for the BZNW cluster.
Crystal Structure of the High-temperature Solid Phases of Choline Tetrafluoroborate and Iodide
Authors: Ishida Hiroyuki , Ono Hiroshi , Ikeda Ryuichi 
Published: February 2015

Abstract
The crystal structure of the highest-and second highest-temperature solid phases of choline tetrafluoroborate and iodide was determined by X-ray powder diffraction. The structure in the highest-temperature phase of both salts is NaCl-type cubic (a = 10.16(2) Å, Z = 4 for tetrafluorobo-rate; a = 10.08(2) Å, Z = 4 for iodide). The second highest-temperature phase of tetrafluoroborate and iodide is CsCl-type cubic (a = 6.198(6) Å and Z = 1) and tetragonal (a = 8.706(2) Å, c = 6.144(6) Å, and Z = 2), respectively. DSC was carried out for the iodide, where the presence of three solid-solid phase transitions was confirmed. Enthalpy and entropy changes of these transitions were evaluated.
High Resolution FTIR Spectroscopy of 1,3,5-Triazine*: The Parallel Bands v11 and v12 of 12C3
14N3H3, 13C3
14N3H3 , 12C3
15N3H3 , 13C3
15N3H3 and 12C3
14N3D3
Authors: Bodenmüller W. , Pfeffer M. , Ruber R. , Macht B. , Ruoff A. 
Published: February 2015

Abstract
The present contribution reports on the analysis of the high resolution FTIR spectra of the only two IR-active parallel fundamentals ν11 and ν12 of the isotopomers 12C3
14N3H3 , 13C3
14N3H3 , 12C3
15N3H3 , C3
15N3H3 and 12C3
14N3D3 , respectively, of 1,3,5-triazine. The molecular constants of the ground state and the upper states ν11 = 1 and ν12 = 1, respectively, for all molecules under consideration are listed. The enhancement of the P-and the depletion of the R-banches, observed in the v11 bands of all non-deuterated isotopomers, is discussed, and the Herman-Wallis constants obtained are given.
Mössbauer Studies of Fe2+ in Iron Langbeinites and other Crystals with Langbeinite Structure
Authors: Windhaus M. , Mosel B. D. , Müller-Warmuth W. 
Published: February 2015

Abstract
57 Fe Mössbauer spectra have been measured at various temperatures between 4.2 K and 300 K for iron langbeinites A 2 Fe 2^04)3 with A = K, NH 4 , Rb, T1 and magnesium, manganese and cadmium lang-beinites doped with Fe" + . The spectra revealed several contributions whose isomer shifts and quadru-pole splittings have been obtained by fitting program routines. For the high-temperature cubic phases two crystallographically non-equivalent iron sites have been identified, characteristic of Fe2+ in the high-spin state. Abrupt changes of the quadrupole couplings indicated phase transitions; in some cases, the spectra have also revealed several sites for Fe2+ in low temperature phases. From the temperature dependences, phase transition temperatures, crystal field splittings and Debye temperatures have been derived.
Internal Cation Mobilities in Molten (K, Dy1/3)Cl
Authors: Matsuura Haruaki , Okada Isao , Takagi Ryuzo , Iwadate Yasuhiko 
Published: February 2015

Abstract
Internal cation mobility ratios in the molten system KCl-DyCl3 have been measured at 1093 K by Klemm's countercurrent electromigration method. From these, and data available on the conductivities and molar volumes of the mixtures, the internal mobilities b of both cations have been calculated. With increasing concentration of Dy, bK decreases. The decrease of bK is attributed to the tranquilization effect by Dy3+ ions which strongly interact with Cl- ions. With increasing concentration of K+ , bDy decreases; this may be attributed to the stronger association of Dy3+ with C- ions due to the enhanced charge asymmetry of the two cations neighboring to the C- ions. It could not been clarified whether a species such as [DyCl6]3- is also an electrically-conducting species in the K+ rich range.
The Molecular Zeeman Effect of Norbornadiene, its g-Values, Magnetizability Anisotropics, and Molecular Electric Quadrupole Moment; A High-Resolution Microwave Fourier-Transform Study Combined with Quantum Chemical Calculations
Authors: Voges K. , Sutter D. H. , Ruud K. , Helgaker T. 
Published: February 2015

Abstract
The molecular Zeeman effect is reported for norbornadiene at fields near 18 kG. The experimental results are for the molecular g-values: gaa = 0.02860(16), gbb = 0.05271(11), gcc = 0.00142(26), for the magnetizability anisotropics: 2ξaa - ξbb - ξcc = -0.41(26) · 10-6 ergG-2 mol-1 , 2ξbb - ξcc - ξaa = +40.72(27) · 10-6 erg G-2 mol-1 and for the molecular electric quadrupole moments: Qaa = -1.78(20) · 10 -26 esu cm2 , Qbb = 3.73(20) · 10-26 esu cm2 , Qcc = -1.94(30) · 10-26 esu cm2 , with the c-axis of the molecular inertia tensor aligned to the C2v-axis of the equilibrium configuration. The results of ab-initio calculations, using London type atomic orbitals as basis functions, are reported for the g-tensor, the magnetizability tensor and the molecular electric quadrupole moment tensor and are compared to the experimental findings. The possibilities of strain induced magnetizability exaltations and of systematic differences between gas phase and bulk phase magnetizabilities are discussed.
An X-ray Diffraction Study of the Structure of Vitreous P2O5
Authors: Hoppe Uwe , Walter Günter , Kranold Rainer , Stachel Dörte 
Published: February 2015

Abstract
Recently, the lengths of the two P-O bonds in the PO4 tetrahedron were obtained by neutron diffraction of high real-space resolution. By use of the present X-ray diffraction experiments, the P-P distance belonging to pairs of corner-linked PO4 units is determined. Using this length of (294 ± 2) pm and taking into account the P-0 bond distance to the bridging oxygen atom of 158 pm, a mean P-O-P angle of 137° ± 3° is calculated. The reverse Monte Carlo simulations fit the neutron and X-ray structure factors. The P-O-P angle distribution obtained this way possesses a mean angle of 141°. An interpretation of the first scattering peaks is presented by analysing the occupancy and the distances of various co-ordination shells by use of model configurations. The low occupancy of the first shells allows the application of the schematic hole model of Dixmier. The first X-ray diffraction peak at 13 nm-1 is related to the P-P2nd shell, the shoulder at 20 nm-1 arises from the P-O2nd shell. The most similar crystalline structure with vitreous P2O5 is the orthorhombic P2O5, form II. But it has more effectively orientated terminal oxygen atoms and, thus, a higher packing than the glass.
Spatio-temporal Analysis of Electroconvection in Nematics
Authors: Amm Heidrun , Grigutsch Maren , Stannarius Ralf 
Published: February 2015

Abstract
We investigate electroconvection in nematic liquid crystals by means of optical microscopy. Time resolved optical images are used to study the director dynamics. For the first time we present instant images in the dielectric regime. A numerical simulation of the optical transmission patterns is performed on the basis of Fermat's principle. In the instant images of dielectric rolls, the periodicity of the observed optical pattern is equal to the wavelength λ0 of the convection rolls. The well known low contrast 'stationary' optical texture observed in conventional experiments results from time averaging of these instant images; its wavelength is λ0/2.
Study of the Atomic Structure and Phase Separation in Amorphous Si-C-N Ceramics by X-Ray and Neutron Diffraction
Authors: Schempp S. , Dürr J. , Lamparter P. , Bill J. , Aldinger F. 
Published: February 2015

Abstract
Amorphous Si37C32N31 and Si37C29N34 ceramics were produced by pyrolysis of a polyhy-dromethylsilazane precursor. Their structure was investigated by X-ray and neutron diffraction. Wide angle diffraction showed that the Si-atoms are preferentially bonded to nitrogen atoms, but also bonding to carbon atoms was found. This suggests that the excess carbon atoms form an amorphous graphite-like phase. Small angle scattering revealed that the ceramics are inhomogeneous. The evolution of the phase separation during annealing was investigated and it was concluded that amorphous Si3N4 precipitates grow in the Si-C-N materials. The results are compared with previous results for amorphous Si24C43N33 produced from a polysilylcarbodiimide precursor [1 - 3].
The Glass Transition Within the Thermodynamics of Irreversible Processes
Authors: Baur H. 
Published: February 2015

Abstract
The glass transition caused by a finite cooling rate is a continuous non-linear dissipative process whose description requires a clear distinction between equilibrium and non-equilibrium quantities. The so-called Davies or Prigogine-Defay relations (in form of an equation as well as in form of an inequality) are not relevant in such a process. The determining quantities of the glass transition are -from a macroscopic phenomenological point of view -the fluidity of the melt and the partial free enthalpy of the microscopic vacancies in the melt. All of the characteristics of the dynamics of the glass transition are essentially due to these two quantities.
Zero Eigenvalue Analysis for the Determination of Multiple Steady States in Reaction Networks
Authors: Li Hsing-Ya 
Published: February 2015

Abstract
A chemical reaction network can admit multiple positive steady states if and only if there exists a positive steady state having a zero eigenvalue with its eigenvector in the stoichiometric subspace. A zero eigenvalue analysis is proposed which provides a necessary and sufficient condition to determine the possibility of the existence of such a steady state. The condition forms a system of inequalities and equations. If a set of solutions for the system is found, then the network under study is able to admit multiple positive steady states for some positive rate constants. Otherwise, the network can exhibit at most one steady state, no matter what positive rate constants the system might have. The construction of a zero-eigenvalue positive steady state and a set of positive rate constants is also presented. The analysis is demonstrated by two examples.
Notiz: The Trouton-Hildebrand-Everett Rule
Authors: Logan S. R. 
Published: February 2015

Abstract
Fundamental scientific reasons are advanced for preferring the formulation of the THE Rule offered in a Note of 1996 to that employed by Rooney in a Note of 1997. These illustrate that, whereas Transition State theory has been of considerable service to the development of chemical kinetics, it has not been of any utility in regard to issues of thermodynamics
Manifestation of Quantum Interference in Lasing Without Inversion
Authors: Lee Hwang , Scully Marian O. 
Published: February 2015

Abstract
In terms of quantum interference we demonstrate the physical mechanisms which lead to light amplification without population inversion. The similarities and differences between the two model schemes, namely, A and V-type, are emphasized. A coherent radiation field, on one hand, which drives one of the lasing levels, yields the quantum mechanical two paths via Autler-Townes splittings. On the other hand, the spontaneous emission in this driving transition plays a key role in the asymmetries between the absorption and the stimulated emission in the lasing transition.