bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduction of Connection Resistance During Veselí Fire Tests
Authors: Jána Tomáš , Wald František
Published: February 2015

The paper is focused to the temperature distribution in the reverse channel connections to concrete filled tubular column during two fire tests on an experimental building in Veselí nad Lužnicí. Temperatures of connections without fire protection as well as fire protected connections were investigated. The connected beams were without fire protection which allows to take into account a membrane action of a composite ceiling without fire resistance reduction of the connections.
Principles of Verification and Validation
Authors: Kwasniewski Leslaw , Bojanowski Cezary
Published: February 2015

This paper discusses the concepts of verification and validation in computational mechanics with special attention to structural fire engineering, by referring to recently published papers and guides on V&V that define some best practices and show directions for future development. The perspective of an analyst, who develops computational models, makes runs, and analyses numerical results mostly using software based on the finite element method, is presented. The considerations emphasize practical problems encountered in the V&V process, potential sources of errors and uncertainties, the importance of sensitivity study, new ideas regarding the relationship between validation and verification, differences between calibration and validation, new aspects of the validation metrics, and guides for designing validation experiments. The discussion is illustrated by computational problem examples.
Recuring Studies on Concretes Subjected to Elevated Temperatures and Suddenly Cooled by Water Quenching
Authors: Yaragal Subhash , Kittur Murugesh , Narayan K.
Published: February 2015

Concrete is found to undergo degradation when subjected to elevated temperatures during an accidental event, such as fire and lose substantial amount of its original strength. The loss of strength in concrete is mainly attributed to the decomposition of Calcium Silicate Hydrate (C-S-H) and release of chemically bound water, which begins when the exposure temperature exceeds 500°C. When such a concrete is supplied with water and allowed to recure, it is found to recover substantial amount of its lost strength. This work is carried out to investigate the effect of recuring on strength recovery of un-blended and blended concrete specimen (100 mm cubes) subjected to elevated temperatures from 400°C to 700°C, in steps of 100°C, for a retention period of two hours at the designated temperatures. The concrete cubes immediately after exposure were subjected to thermal shock by quenching them in water, and then temperature of thermally shocked concrete is allowed to cool to room temperature. The cooled specimen were then recured in water for 1, 3, 7, 14, 21, 28, 56 days and tested for compressive strength recovery. These studies were carried out for Portland Cement (PC) based concrete and Portland & Granulated Blast Furnace Slag (70% PC + 30% GGBS) based concrete (blended concrete), and some interesting results are presented and discussed in this paper.
A united approach to the prevention of pressure ulcers
Authors: Gray Sarah , Hampton Sylvie
Published: February 2015

Pressure ulcers are a serious but treatable condition. Sarah Gray and Sylvie Hampton advise on how health professional must join forces to ensure pressure ulcers are prevented where possible, and treated appropriately if necessary
Having your cake and eating it: is obesity a disability?
Authors: Jones Nick , Hobbs Matthew
Published: February 2015

A morbidly obese man is sacked from his job because of his weight. Illegal discrimination or reasonable decision? Is obesity self-inflicted or can it not be helped? Does it even matter? Nick Jones and Matthew Hobbs eye the legal implications of a test case in Denmark
The principles of infection prevention and control
Authors: Green Danielle
Published: February 2015

This optional unit assesses the care worker's knowledge of national and local infection control policies; of employer and employee infection control responsibilities and of how procedures and risk assessment can help minimise the risk of an outbreak of infection
Six Nations fever
Authors: Cruickshank Sarah
Published: February 2015

International sports competitions provide an exciting opportunity to explore a range of sports and the cultures of participating countries. Sarah Cruickshank offers some ideas on using the Six Nations rugby championship.
Springing to attention
Authors: Hampshire Viv
Published: February 2015

Help the children to use one of their senses for a unique exploration of spring. In these activities we will be focusing on sounds, particularly those we are likely to encounter at this time of the year.
Peter Sedgwick: mental health as radical politics
Authors: Tietze Tad
Published: February 2015

This article examines the life, Marxist politics and critical psychiatric theory of Peter Sedgwick, author of Psychopolitics (1982). Sedgwick critically engaged with the ideas of key anti-psychiatric thinkers, including Goffman, Laing, Szasz and Foucault. His theoretical contribution – of the social construction of health and illness, mental and otherwise – underpinned a focus on the politicisation of medical goals within projects for social transformation. His ideas remain highly relevant to modern psychiatric debates and controversies.
Quantitative detection of amyloid-β peptides by mass spectrometry: state of the art and clinical applications
Authors: Bros Pauline , Delatour Vincent , Vialaret Jérôme , Lalere Béatrice , Barthelemy Nicolas , Gabelle Audrey , Lehmann Sylvain , Hirtz Christophe
Published: February 2015

Alzheimer’s disease (AD) is the most common form of dementia in humans, and a major public health concern with 35 million of patients worldwide. Cerebrospinal fluid (CSF) biomarkers being early diagnostic indicators of AD, it is essential to use the most efficient analytical methods to detect and quantify them accurately. These biomarkers, and more specifically amyloid-β (Aβ) peptides, are measured in routine clinical practice using immunoassays. However, there are several limits to this immunodetection in terms of specificity and multiplexing of the multiple isoforms of the Aβ peptides. To overcome these issues, the quantification of these analytes by mass spectrometry (MS) represents an interesting alternative, and several assays have been described over the past years. This article reviews the different Aβ peptides quantitative MS-based approaches published so far, compares their pre-analytical phase, and the different quantitative strategies implemented that might be suitable for clinical applications.
The ε - εβproperty, the boundedness of isoperimetric sets in ℝNwith density, and some applications
Authors: Cinti Eleonora , Pratelli Aldo
Published: February 2015

We show that every isoperimetric set inℝN{\mathbb{R}^{N}}with density is bounded if the density is continuous and bounded above and below. This improves the previously known boundedness results, which basically needed a Lipschitz assumption; on the other hand, the present assumption is sharp, as we show with an explicit example. To obtain our result, we observe that the main tool which is often used, namely a classical “ε--ε” property already discussed by Allard, Almgren and Bombieri, admits a weaker counterpart which is still sufficient for the boundedness, namely, an “ε--εβ\varepsilon^{\beta}” version of the property. And in turn, while for the validity of the first property the Lipschitz assumption is essential, for the latter the continuity alone is enough. We conclude by deriving some consequences of our result for the existence and almost-everywhere regularity of isoperimetric sets.
Curvature flow in hyperbolic spaces
Authors: Andrews Ben , Chen Xuzhong
Published: February 2015

We study the evolution of compact
convex hypersurfaces in
hyperbolic space

ℍ

n
+
1

{\mathbb{H}^{n+1}}

, with normal speed governed by the curvature. We concentrate mostly on the case of surfaces, and show that under a large class of natural flows, any compact initial surface with Gauss curvature greater than 1 produces
a solution which converges to a point in finite time, and becomes
spherical as the final time is approached. We also consider the higher-dimensional case, and show that under the mean curvature flow a similar result holds if the initial hypersurface is compact with positive Ricci curvature.
The role of perivascular adipose tissue in vasoconstriction, arterial stiffness, and aneurysm
Authors: Villacorta Luis , Chang Lin
Published: February 2015

Since the “rediscovery” of brown adipose tissue in adult humans, significant scientific efforts are being pursued to identify the molecular mechanisms to promote a phenotypic change of white adipocytes into brown-like cells, a process called “browning”. It is well documented that white adipose tissue (WAT) mass and factors released from WAT influence the vascular function and positively correlate with cardiac arrest, stroke, and other cardiovascular complications. Similar to other fat depots, perivascular adipose tissue (PVAT) is an active endocrine organ and anatomically surrounds vessels. Both brown-like and white-like PVAT secrete various adipokines, cytokines, and growth factors that either prevent or promote the development of cardiovascular diseases (CVDs) depending on the relative abundance of each type and their bioactivity in the neighboring vasculature. Notably, pathophysiological conditions, such as obesity, hypertension, or diabetes, induce the imbalance of PVAT-derived vasoactive products that promote the infiltration of inflammatory cells. This then triggers derangements in vascular smooth muscle cells and endothelial cell dysfunction, resulting in the development of vascular diseases. In this review, we discuss the recent advances on the contribution of PVAT in CVDs. Specifically, we summarize the current proposed roles of PVAT in relationship with vascular contractility, endothelial dysfunction, neointimal formation, arterial stiffness, and aneurysm.
Analysis and Suppression of SBS Effect Using Self-Phase and Cross-Phase Modulation
Authors: Tithi F. H. , Islam M. S. , Tanna T. A.
Published: February 2015

Stimulated Brillouin scattering (SBS) is one kind of fiber nonlinearities representing the fundamental limiting mechanisms to the amount of data that can be transmitted on a single optic fiber. SBS is the main limiting factors for getting high output fiber. To achieve high output power and high threshold power we have to suppress this SBS effect. When light ray propagates through an optical fiber, spectral broadening is occurred due to the self-phase modulation (SPM) and cross-phase modulation (XPM) effect. In this paper, we analyze the effect of spectral broadening due to the SPM and XPM and using this effect we minimize SBS effect. From the numerical simulation results, we have found that spectral broadening factors are 1.058, 1.217 and 1.443 for input power 30, 60 and 90 mW, respectively, due to SPM effect at 10 km transmission length. Using these broadening factors and input optical powers, the amounts of threshold power improvements are 2.1, 3.2 and 4.5 mW, respectively, for a source spectral width of 200 MHz. We also analyze this XPM effect considering equal channel power and unequal channel power.
Three-dimensional Analytical Force-free MHD Equilibria
Authors: Lortz D. , Lötz W. , Nührenberg J. , Cap F.
Published: February 2015

Three-dimensional analytical force-free magnetohydrostatic equilibria may be obtained by separation of variables with respect to cylindrical coordinates. These equilibria are then used to study numerically flux surfaces of various three-dimensional configurations.
Röntgen-Beugungsuntersuchungen an Bi-In-Schmelzen / X-Ray Diffraction Experiments with Bi-In-melts
Authors: Bek R. , Nold E. , Steeb S.
Published: February 2015

Using MoK α-radiation and a θ-θ diffractometer from molten In and Bi as well as six molten Bi-In alloys (8; 22; 27; 33.3; 50; and 77 at % Bi) intensity curves were obtained at 10 °C above the liquidus temperature. The measurements were performed in the q-region up to 14.5 Å-1. From the Fourier transform of the structure factors coordination numbers NI
tot and radii rI
tot were obtained. The concentration dependency of NI
tot and rI
tot leads to the conclusion, that the Bi-In melts belong to the compound forming melts.
Zur Korrelation von 0-0-Übergängen, Absorptions- und Fluoreszenzmaxima mit σ-Hammett-Konstanten / The correlation of the 0-0-transitions and the maxima of absorption and fluorescence with theσ-Hammett constants.
Authors: Polansky O. E. , Fratev F. , Nikolov P.
Published: February 2015

The correlation of the 0-0-transitions and the maxima of absorption and fluorescence with the σ-Hammett constants. The correlation of the 0-0-transitions and the maxima of absorption and fluorescence with the ff-Hammett constants lead to conclusions concerning the changes in the gap of the state involved and their curvatures due to substitution. The formalism can be applied also using other LFER parameters than σ-Hammett constants.
EPR Study of Hydration of Portland Cement
Authors: Lasič D. D. , Lahajnar G. , Blinc R. , Kocuvan I.
Published: February 2015

The microscopic nature of the solidification of cement was studied via a measurement of the time dependence of the fraction of freely rotating spin probes by electron paramagnetic resonance with and without added retardants.

The results seem to support the osmotic theory of cement hydration.
Ein einfaches graphentheoretisches Verfahren zur Abschatzung der Resonanz- und Grenzorbitalenergien alternierender polycyclisdier aromatisdier Kohlenwasserstoffe / A Simple Graph-theoretical Scheme for the Estimation of Resonance and Frontier Orbital Energies of Alternant Polycyclic Aromatic Hydrocarbons
Authors: Gundermann K.-D. , Lohberger C. , Zander M.
Published: February 2015

From the characteristic graphs of alternant polycyclic aromatic hydrocarbons (kata-annellated and peri-condensed systems) a topological index is derived, which can be calculated very easily even for highly complex aromatic systems and correlates satisfactorily with both the Dewar resonance and HMO frontier orbital energies. The graph-theoretical scheme provides a simple means for the rapid estimation of these data for unknown aromatic systems
Correlation of Zero Field Splittings and Site Distortions III. MnBr4
2- and Crystal Structure Refinements for Rb3ZnBr5 and Cs2ZnBr4
Authors: Heming M. , Lehmann G. , Henkel G. , Krebs B.
Published: February 2015

EPR data for Mn2+ in Cs2ZnBr4, Rb3ZnBr5, Cs3CdBr5 and [(CH3)4N]2ZnBr4 single crystals were determined and the crystal structures of Rb3ZnBr5 and Cs2ZnBr4 were refined. Superposition analysis of the fine structure data for the latter two compounds resulted in an intrinsic zero field splitting parameter b̄2 for MnBr4
2- of + 0.44 cm-1 suggesting a sizeable positive contribution of covalency. Cs3CdBr5 was prepared in single crystals for the first time. It crystallizes in a primitive tetragonal space group. From the fine structure parameter 62° and the above value of b̄2 an elongation of the CdBr4
2- tetrahedra along the c-axis with a bond angle of 105.7° was determined. This result is in agreement with the anisotropy of the 55Mn hyperfine splitting constant with A|| = -68.6 and A±= - 70.6 • 10-4 cm-1
Zwischenmolekulare Schwingungskopplung. Oberwellen von 12CO3– – -Kctten beim 13CO3– – substituiertcn BaCO3 / Intermolecular Vibrational-Coupling of the Out-of-plane-vibration. Short Waves of 12CO3
2- -chains in 13CO3— Enriched BaCO3
Authors: Zehnder E. J. , Sterzel W.
Published: February 2015

The IR-spectra of BaCO3 (80% 13CO3
2-, 90% 13CO3
2-) shows small bands in the ν2-region, which are assigned to short waves of 12CO3
2--chains with three, five or six carbonate ions
Correlations Between Carbonyl Vibrational Properties of Polycyclic Aromatic Aldehydes and Electronic Properties of the Corresponding Hydrocarbons
Authors: Gundermann K. D. , Lohberger C. , Zander M.
Published: February 2015

Good correlations exist between both the carbonyl stretching frequency and the carbonyl bond order of the monoaldehydes of polycyclic aromatic hydrocarbons and the HMO atom localisation energies or PMO reactivity numbers of the corresponding hydrocarbons at the carbon centres contiguous to the CHO group. Applications of these correlations are discussed
Two Photon Ionization of Liquid Tetramethyl Silane
Authors: Böttcher H. , Schmidt W. F.
Published: February 2015

The photoconductivity of neat liquid tetramethyl silane subjected to an intense UV laser flash was studied as a function of laser power. Charge carrier generation was found to proceed via double photon ionization
Entropies and Heat Capacities of Gaseous Selenium Molecules Sen (n = 5 ... 12)
Authors: Steudel Ralf
Published: February 2015

Thermodynamic functions are calculated for gaseous Se8 molecules from spectroscopic and structural data and listed for temperatures up to 3000 K. Entropy (S°) and heat capacity (Cp
0) data for Sen molecules (n = 5, 6, 7, 9, 10, 11, 12) are obtained from linear relationships between both S0 and Cp
0 and ring size n which are derived from the corresponding values of Se2 and Se8
On the Use of Atom-Localized Molecular Orbitals
Authors: Sahini V. E. , Savin A.
Published: February 2015

Atom-localized molecular orbitals are defined and discussed for alternant hydrocarbons, in the HMO approximation
T2-Measurement on a Dipole-forbidden Transition of OCS
Authors: Bomsdorf H. , Dreizler H.
Published: February 2015

A double resonance pulse sequence experiment is described allowing the determination of the rotational relaxation time of certain dipole-forbidden transitions. Measurements on the pres­ sure dependence of To for the dipole-forbidden transition J = 0, M = 0 → J = 2, M = 0 of OCS have been performed using a superhet bridge type transient spectrometer. No significant difference of the results is found compared with measurements on the dipole-allowed transitions J = 0, M = 0 → J = 1, M = 0 and J = 1, M = 0, ± 1 → J = 2, M = 0, ± 1.
Dielektrische Relaxation starrer Dipolmoleküle in unpolaren Mischlösungsmitteln
Authors: Hufnagel F. , He Shi Ding
Published: February 2015

In isotropic mixtures of nonpolar aliphatic solvents the Debye relaxation time of rigid polar solutes is studied. It is represented by a characteristic libration frequency, an effective molecular diameter and the activation factor originating from the neighbourhood of the dipole molecule. The dependence on temperature of both relaxation time and viscosity yields a relation between them, so that a microscopic picture of the solvents cage can be given.
Centrifugal Distortion Effect in the Microwave Spectrum of 1,3-Dioxane-5-ol
Authors: Roman A. , Alonso J. L. , Mata F.
Published: February 2015

The microwave spectrum of 1,3-Dioxane-5-ol has been analysed in the frequency region 18.0-40.0 GHz and up to J = 30. The analysis gives refined rotational constants and values for the quartic centrifugal distortion parameters. Comparison is made between the results using two forms of the quartic Hamiltonian
EPR Study of the Molecular Ordering in the Liquid Crystal: HBT
Authors: Rao A. S. N. , Murty P. Narayana , Murty C. R. K. , Reddy T. Rs.
Published: February 2015

Ordering of molecules is observed in the nematic and smetic-B phases of the liquid crystal HBT below 74 °C. In the Sb phase there is a considerable decrease in the intensity without increase in the width of the EPR lines. This unusual behaviour is believed to be due to a order-disorder state with layers coupled by strong forces
Proton and Fluorine-Spin-Lattice Relaxation in Poly crystalline FeSiF6 • 6 H2O
Authors: Rager H.
Published: February 2015

The proton and fluorine nuclear spin-lattice relaxation has been measured in FeSiF6 • 6H2O in the temperature range 130 K ≦ T ≦ 420 K with standard pulse methods at 30 MHz. The relaxation times, T1(1H) and T1(19F), decrease with decreasing temperature according to the expression T1=a(I)exp(-Δ/T) (I = 1H, 19F). They show no significant dependence on the Larmor frequency. Thus, the unpaired Fe2+ electrons are mainly responsible for the proton and fluorine spin-lattice relaxation. The relaxation mechanism is described by an Orbach process. The ratio T1(19F)/T1(1H) is relatively constant over the whole temperature range investigated. This is explained by the strong H ... F bonds in FeSiF6 · 6H2O. The sharp increase of T1(1H) and T1(19F) at 224 K is attributed to the phase transition, which probably alters the crystal field at the Fe2+ centers
Host-Guest Energy Transfer Via Dipole-Dipole Interaction in Doped Fluorene Crystals
Authors: Port H. , Schneckenburger H. , Wolf H. C.
Published: February 2015

Fluorene mixed crystals have been investigated by sensitized fluorescence measurements in order to prove the importance of dipole-dipole interactions for singlet energy transfer. Fluorene: dibenzofuran (F:DBF) and fluorene:benz[f]indan (F:BI) are used. In these systems the optical transition dipole moments of host and guest molecules are perpendicular and parallel to one another, respectively. For these systems the host-guest energy transfer rate has been determined as a function of the guest concentration from the quantum ratio of guest and host emission (F:BI) and from fluorescence decay time measurements (F:DBF). The latter verified the particularly low transfer rate in F : DBF found in previous steady state investigations. The measured transfer rates at 1.3 K could be explained quantitatively taking into account the relative orientations of the host and guest transition dipoles and the oscillator strengths of the optical transitions. An increase of the transfer rate with increasing temperature between 1.3 K and 100 K in the system F: BI could be related to a change from energy transfer within perturbed states to excitonic band states of the fluorene crystal.
The Influence of Surface Structure on the Photoelectrochemistry of Polycrystalline n-TiO2-Films
Authors: Liditscheidl J. , Hartig K. J. , Getoff N. , Tauschnitz Ch. , Nauer G.
Published: February 2015

The relationship between the surface structure, film thickness and the photoelectrochemical behaviour (photocurrent, corrosion and stability) of n-Ti02-films produced by controlled thermal oxidation of titanium foils is carefully investigated. X-ray surveys, optical and scanning electron microscopical observations were performed to elucidate the surface structure. It is established that a special etching procedure of Ti-metal foils, followed by controlled oxidation at 600 to 700 °C for 10 to 30 min in the presence of sufficient oxygen results in n-Ti02 layers with a defined surface structure and high photoactivity. As charge transfer through the Schottky barrier is decisive for the photoefficiency, the formation kinetics of the oxide layer is the most influencing factor.
Splitting of Terms Beyond a D-Term in an Octahedral Ligand Field
Authors: Perumareddi J. R.
Published: February 2015

Although the procedure to calculate the ligand field energies of terms of a many d-electron configuration in cubic symmetry is known, we present a novel semiquantitative method for the splitting of d-electron terms in cubic symmetry. The method is based on quantitative calculations of one-electron orbitals of a given angular momentum. S p littin g o f T e r m s B e y o n d a D -T e r m in a n O c ta h e d r a l L ig a n d F ield
Interaction of the C = N Bond with the Cyclopropyl Ring
Authors: Al-Siaidi Shatha F. , Ibrahim Ibrahim T. , Shanshal
Published: February 2015

The conjugative interaction of the C=N bond with the cyclopropylring is studied using UV-spectrophotometric technique. The observed small bathochromic shift in the n-n* bands, relative to the spectra of similar compounds but with no cyclopropylring, is attributed to the interaction of the internal Walsh MO with the nonbonded MO of the Nitrogen atom (Zlint-n interaction) in the bisected conformation of the molecule. The observed bathochromic shifts of the 71-71* bands are explained in terms of the A-n interaction. The gas phase spectra of the azomethine derivatives show vibronic structuring of the band which when analyzed yeld wave number differences be­ tween the successive vibronic peaks, of the magnitude 720—860 cm-1. They are attributed to to the wave number differences between the successive C—N=C deformed ion levels in the excited state. I n te r a c tio n o f th e C = N B o n d w ith th e C y c lo p r o p y l R in g
Vibrations of a Cage-like Molecule, P4S3: Some Theoretical Aspects
Authors: Cyvin S. J. , Cyvin B. N. , Somer M. , Brockner W.
Published: February 2015

Two independent symmetry coordinate sets for P4S3 are developed, starting from the "method of fragments". A simple, approximate force field is expressed in terms of the two sets of symmetry coordinates, and the corresponding compliance matrices are given. The invariance of compliants is demonstrated. The potential energy distribution (PED) is discussed. An example is shown where the PED terms are clearly inadequate for the description of normal modes. A general warning against the interpretation of the PED in terms of such descriptions for cage-like structures seems to be warranted. V ib r a tio n s o f a C a g e -lik e M o le c u le , P 4S3 : S o m e T h e o r e tic a l A sp e c ts
Confinement and Radical Unification in Functional Quantum Theory of the Nonlinear Spinorfield
Authors: Stumpf H.
Published: February 2015

The conditions are discussed under which in functional quantum theory of the nonlinear spinorfield with indefinite metric the probabilistic interpretation can be restored. This leads to a close connection of confinement, composite particles and the new subquark models of matter.
Effect of an Electric Field on Electron Attachment to SF6 in Liquid Ethane and Propane
Authors: Bakale George , Schmidt Werner F.
Published: February 2015

The effect of an external electric field, E, on the electron attachment rate constant, ke, of SF6 was studied by a pulsed-conductivity technique in liquid ethane and propane at temperatures ranging from 133-176 K and 156-216 K, respectively. At constant temperature, ke was independent of E at fields less than Ec , the critical field above which the mobility becomes field-dependent, but at E> Ec, ke increased proportionally with De, the diffusion coefficient of the electron. Application of diffusion-controlled reaction theory to the ke - De dependence yielded an effective encounter radius of 14.5 Å for the e--SF6 reaction pair in both liquids. This encounter radius is discussed in terms of the electron-SF6 interaction energy and models of electron transport and attachment in low-mobility liquids.
Vibrational Spectra and Force Constants of Tetrasulfurtetranitride, S4N4 [1]
Authors: Steudel Ralf
Published: February 2015

Infrared and Raman spectra of solid and dissolved S4
14N4 and of solid S4
15N4 have been recorded and assigned in accordance with the molecular point group D2d. 22 of the 28 fundamental vibrations of both molecules have been identified and used to calculate force constants applying a modified Urey-Bradley force field with 9 independent constants. Good agreement between observed and calculated wavenumbers was obtained, and both Urey-Bradley and valence force constants are given. The results indicate that-S4N4 basically contains eight SN single bonds and two extremely weak SS bonds.
Microwave Rotational Spectra of 2-Bromofurane and 3-Bromofurane and Bromine Nuclear Quadrupole Coupling Tensors
Authors: Stolze M. , Hübner D. , Sutter D. H.
Published: February 2015

The vibronic ground state rotational spectra are reported for the 79Br-and 81Br-species of 2-Bromofurane and 3-Bromofurane. Both μa and μb-type spectra were observed. The small inertia defects confirm that the equilibrium configurations are planar. From the nuclear quadrupole coupling tensors it may be concluded that π-contributions to the C-Br bonds are smaller than in the Halobenzenes.
Dissociation Energy of the SbPb Moleculc from Mass Spectrometric High Temperature Studies
Authors: Zmbov K. F. , Neubert A. , Ihle H. R.
Published: February 2015

The observation of the gaseous BiPb molecule [1,2] suggests the existence of heteronuclear diatomic molecules of lead with the group V-b elements. The present paper reports on the identification of the SbPb(g) molecule and the determination of its dissociation energy by mass spectrometric Knudsen-effusion method.
Electronic Structure of Metallic Glasses from the Cu-Zr-and Cu-Ti-Systems as well as from some Transitionmetall-Metalloid- Systems by Means of X-Ray-Emission Spectroscopy
Authors: Falch Siegfried , Rainer-Harbach Georg , Schmückle Friedrich , Steeb Siegfried
Published: February 2015

Using an electron microprobe, the position and shape of the characteristic X-Ray emission lines from the elements Cu, Zr, Ti, Fe, Co, and Mn in metallic glasses of the systems Cu-Zr, Cu-Ti, Fe-B, Fe-P, Co-B, Co-P, Fe-Ge-P, Mn-Si-P, and Fe-Si-P were studied. In each case the lines were compared with those of either the crystalline element or the corresponding crystalline compound. Compared to electron spectroscopy methods such as XPS or UPS, the method used during this work has the advantage that the spectra obtained are specific for the corresponding element. The general trend of the results can be described in such a way that the energy of binding of the electrons to the corresponding atomic species is larger in the amorphous state than in the crystalline element, whereas the energy of binding of the electrons in the amorphous state is similar to that of the corresponding crystalline compound.
Generation of Gravitational Radiation in the Laboratory
Authors: Romero B. F. , Dehnen H.
Published: February 2015

The generation of gravitational radiation by coherent excitation of a long row of oscillators is investigated. In particular we have considered diatomic linear chains as an idealization of thin piezoelectric crystals. We find a highly focussed superradiant beam of gravitational radiation in direction of the row and a total radiation power larger than the incoherent superposition of the oscillator radiation by the factor λ̲/a (λ̲ wavelength*, a distance between neighbouring oscillators). In spite of these optimum conditions it seems to us that the attainable magnitude of the radiation power of approximately 10-22 erg/sec is not high enough for a successful laboratory experiment.
Synthesis and Mesomorphic Properties of 4,4'-Di-n-alkyl-bibicyclo[2.2.2]octanes
Authors: Reiffenrath V. , Schneider F.
Published: February 2015

The homologous series of di-alkyl-bibicyclo[2.2.2]octanes (methyl to octyl) was prepared. All homologues with the exception of the methyl compound show broad smectic phase ranges. For the pentyl homologue the smectic phase exists between 46 °C and 247 °C. X-ray investigations show a novel type of diffraction pattern.
Bestimmung der Beweglichkeit von Plutonium (VI) in wäßriger Lösung bei 298 K durch Leitfähigkeitsmessung / Determination of Ionic Mobilities of Plutonium (VI) in Aqueous Solutions at 298 K by Use of Conductivities
Authors: Arndt F. , Marx G.
Published: February 2015

In pure water the limiting ionic conductance of (1/2PUO2
2+)was found to be 59 cm2 Ω-1 mol-1 by use of conductivity measurements of PuO2(NO3)2 in diluted nitric acid and applying Kohlrausch's law. The values obtained were compared with those of other actinide-ions.
The X-ray Structure Factor of Liquid Glycerol
Authors: Soltwisch M. , Steffen B.
Published: February 2015

The X-ray scattering intensity from highly viscous, liquid glycerol has been measured using MoKα-radiation (0.2 < qÅ < 10) between 250 K and 350 K. The corrected spectra were Fourier transformed to obtain the atomic radial distribution function.

For increasing temperatures one observes an increase of the X-ray intensity before the first structure maximum, and a broadening and a shift to lower-q-values of the main peak, while the peak height remains nearly constant.

The temperature dependent structure factors are compared with a model calculation, which in a simple way gives the correct compressibility limit. From the fits to the structure maximum the existence of orientational correlations is inferred.
Molecular Orbital Calculations of Cu-Halides
Authors: Itoh H.
Published: February 2015

An ab initio HF MO theory is applied to CuX, CuX2 (X = F and Cl) and (CuCl)3 . Although the detailed sequence of energy levels depends upon the basis set used, high-lying orbital energy levels have largely halogen p-like character, whereas low-lying orbital energy levels have largely Cu 3 d-like character. This is in agreement with the chemical intuition of a highly ionic character of these compounds.
Some Properties of Molten KCl at High Density Studied by MD Simulation
Authors: Takagi Ryuzo , Okada Isao , Kawamura Kazutaka
Published: February 2015

Molecular dynamics simulations of molten KCl have been performed at 1173 K with the molar volumes of 52.0 (the value under ambient pressure), 50.0, 48.0 and 45.0 cm3 mol-1 . Some thermodynamic properties at higher densities have been evaluated, which are generally in good agreement with the experimentally obtained ones and Monte Carlo results. Both at normal and higher densities, the self-exchange velocities of neighbouring unlike ions (SEV) are found to be proportional to the internal mobilities with nearly the same constant as derived previously for molten LiCl, RbCl and their 1 : 1 mixture. Calculated transport properties such as the SEV and the self-diffusion coefficients considerably decrease with increasing density, while the configuration does not change much.
Topological Studies on Heteroconjugated Molecules. III. On the Law of Alternating Polarity
Authors: Gutman Ivan
Published: February 2015

The π-electron charge Qs
h in alternant conjugated systems with one heteroatom is considered. A complete proof of the law of alternating polarity is presented. The integral expression for Qs
h is decomposed into a number of relatively simple terms, which give some insight into the dependence of Qs
h, on molecular topology.
Zum spektroskopischen Verhalten ausgewählter 1,2-Diazepine / On the Spectroscopic Behaviour of Selected 1,2-Diazepines
Authors: Abraham W , Kupfer M. , Buck K. , Kreysig D.
Published: February 2015

The absorption and emission spectra of three aryl-1,2-diazepines are discussed in comparison to arylcycloheptatrienes. The nitrogen atoms in the seven membered ring increase the acceptor strength of this ring system. The solvatochromism of absorption and fluorescence is discussed by multiple correlation of transition energies with solvent parameters π* and α. Like cycloheptatrienes the diazepines show dual fluorescences with quantum yields depending on excitation energy. The ratio of the intensities of short wavelength emission and long wavelength emission depends strongly on the solvent.
Topologische Indices alternierender polycyclischer aromatischer Kohlenwasserstoffe und ihre Korrelationen mit elektronischen Eigenschaften / Topological Indices of Alternant Polycyclic Aromatic Hydrocarbons and their Correlations with Electronic Properties
Authors: Gundermann K.-D. , Lohberger C. , Zander M.
Published: February 2015

The half-sum of the distance matrix elements derived from the characteristic graphs, i.e. the Wiener number of these graphs is proposed as a new topological index for alternant polycyclic aromatic hydrocarbons. It is shown by regression analysis that correlations between topological indices and electronic properties of alternant aromatic systems do only exist for those indices and properties which depend to the same degree from the size of the systems and for which the corresponding relation applies to the topology.
Application of the Hard Sphere Theory to the Diffusion of Binary Liquid Alloy Systems
Authors: Schwitzgebel G. , Langen G.
Published: February 2015

On the basis of the van der Waals concept of Ascarelli and Paskin the hard sphere theory of self diffusion is extended to binary liquid alloys. Using only the melting temperature of the pure metals and the densities, component self-diffusion coefficients and, with the help of Darken’s equation, mutual diffusion coefficients were calculated. Agreement with experimental results is good in (Bi, Sn), and excellent in (Sn, Zn) and (Li, Ag). Impurity diffusion in liquid Cu, Sn and Pb is predicted better than by the theory of Protopapas et al. Deviations in (Hg, Zn) and (Li, Pb) are tentatively attributed to strong particle interactions in one component (Hg) or in the alloy (Li, Pb).
Notizen: Electric Field Dependence of the Ionization Threshold of Benzene and the Benzene-Argon Complex
Authors: Fung K. H. , Selzle H. L. , Schlag E. W.
Published: February 2015

The ionization potential measured as a threshold to photoionization for benzene and the benzene-argon com­plex is shown to be a strong function of the applied electric field required to detect the ionization event. The ionization potential is lowered by moderate electric fields and the field dependence is found to be the same for the bare molecule and its Van der Waals complex. The data can be fitted with a square root dependence on the electric field and this shows that large molecules behave like atoms at the ionization threshold.
Notizen: Anisotropic Fluorescence of Donor-Acceptor-Substituted trans-Stilbenes in Solvents of Different Polarities and Low Viscosity
Authors: Kawski A. , Alicka M. , Gloyna D.
Published: February 2015

The fluorescence anisotropy (FA) and mean lifetime τF of substituted trans-stilbenes was investigated at 293 K in the nonpolar and polar low viscosity solvents n-heptane, toluene, acetonitrile, dimethylformamide and n-propanol. In most cases, the fluorescence was found to be strongly anisotropic due to a very short lifetime of the donor- acceptor-substituted trans-stilbenes.
Empirical Verification of Recently Proposed Hadron Mass Formulas
Authors: Mielke Eckehard W.
Published: February 2015

For the nucleon resonances as well as for the heavy vector mesons different mass formulas are compared. Those corresponding to a band of rotational excitations of the particle seem to agree rather well with the existing data.
Determination of Diffusion Parameters of Solved Molecules by Measuring the Relaxation Kinetics on the Picosecond Time Scale
Authors: Heumann E.
Published: February 2015

Picosecond probe beam spectroscopy is used to measure the nonstationary contribution to diffusion controlled excimer formation in dependence on concentration and solvent viscosity. Utilizing a kinetic model, the effective encounter radius and diffusion parameters of pyrene molecules in different solvents have been determined.
Carbon-13 NMR and Raman Scattering Studies of Potassium Propoxybenzoate and Potassium Butoxybenzoate. Conformational Change Due to Micellization
Authors: Okabayashi Hirofumi , Yoshida Tadayoshi , Terada Yukimasa , Ikeda Teruki , Matsushita Kazuhiro
Published: February 2015

Carbon-13 NMR chemical shifts and carbon-13 spin-lattice relaxation times of potassium propoxybenzoate and potassium butoxybenzoate in deuterium oxide solution were measured at various concentrations.

For the alkoxy group, the earbon-13 resonance peak of the O-CH2 segment is shifted rapidly up-field upon micellization, while the resonance peaks of other methylene groups are shifted downfield. This observation is ascribed to the conformational change of the alkoxy group on micellization.

In the monomolecular solution of potassium butoxybenzoate, the restricted state of the O-CH2 bond was estimated by carbon-13 spin-lattice relaxation time measurement. It was also found that micellization brings about a further restricted internal rotation about the O-CH2 bond.
The Microwave Spectrum of Imidazole; Complete Structure and the Electron Distribution from Nuclear Quadrupole Coupling Tensors and Dipole Moment Orientation
Authors: Christen Dines , Griffiths John H. , Sheridan John
Published: February 2015

Spectra have been measured for eleven isotopic forms of imidazole, including single substitutions at each nucleus in turn. A complete rs-structure is obtained. The ring structure is:

N(1)-C(2) = 1.364 Å, C(2)-N(3) = 1.314 Å, N(3)-C(4) = 1.382 Å, C(4)-C(5) = 1.364 Å, C(5)-N(1) = 1.377 Å, ≮N(1)C(2)N(3) = 112.0°, ≮C(2)N(3)C(4) = 104.9°, ≮N(3)C(4)C(5) = 110.7°, ≮C(4)C(5)N(1) = 105.5° and ≮C(5)N(1)C(2) = 106.9°.

The N(1)-H(1) distance is 0.998 Å, while the C-H distances are all very close to 1.078 Å. The bonds N(1)-H(1) and C(2)-H(2) lie close to the external bisectors of the respective ring angles, but C(4)-H(4) and C(5)-H(5) are each displaced by several degrees from these bisectors towards N(3) and N(1) respectively. The electric dipole moment is established as 3.67 (5) D from Stark effects, directed almost parallel with the line joining the nitrogen nuclei. The properties and orientations of the two 14N-nuclear quadrupole tensors have been investigated, in particular through the spectra of the two mono-14N-imidazoles.
To the Mathematical Concept of Thermostatics To the Mathematical Concept of Thermostatics
Authors: Grauel A.
Published: February 2015

We discuss the integrated form of the laws of thermostatics by using Stokes theorem on manifolds. We give a new insight to the basic properties of thermostatics, in particular we show that only the second law is a necessary condition to identify the integrating factor with the temperature. Moreover we consider the thermodynamical field equations for discontinuous media and discuss the properties of thermostatics.
Semiempirische Rechnungen zum Einfluß des Lösungsmittels auf die Protonierungsenergie des Anilins, des Ammoniaks und einiger aliphatischer Amine
Authors: Fleischhauer Jörg , Raabe Gerhard
Published: February 2015

The MINDO/3- and the MNDO-method have been used to determine the site of protonation of Aniline in the gas phase. We used the results of our semiempirical calculations together with the electrostatic "Solvaton-Model" to study the influence of the solvent on the energetics of the protonation of some amines and the site of protonation in Aniline. Our results indicate that the "Solvaton-Model", although neglecting specific interactions between solvent and solute such as the formation of hydrogen bonds, describes the change of the energy of solvation during the protonation in a rather successful agreement with experimentel results.
Infrared Studies of Rotational and Vibrational Relaxation in Liquid Cyclohexane
Authors: Bien T. , Döge G. , Yarwood J. , Arnold K. E.
Published: February 2015

Molecular correlation functions have been determined for the infrared active vibrations ν16, ν29 , ν30 and ν31 of neat liquid cyclohexane at different temperatures. The results have been com-pared with calculated reorientational correlation functions.
Energy Transfer Among Like and Unlike Molecules in Solution VI. Effect of the Mediation of Donor Molecules Upon the Electronic Excitation Energy Transfer in Binary Systems
Authors: Kawski A. , Szmaciński H.
Published: February 2015

The effect of an interdonor energy transfer is investigated on the following donor-acceptor systems in thin rigid cellulose acetate films: anthracene and tetracene (I), 9-methylanthracene and 2-aminobenzophenone (II), 9,10-diphenylanthracene and 2-aminobenzophenone (III). The donor quantum yield and fluorescence anisotropy in systems I-III are in good agreement with theoretical predictions for a model of a multi-step excitation energy transfer process. In mixed two-component solutions the donor fluorescence anisotropy is higher than in single-component solutions, indicating an interdonor excitation transfer preceding the donor-acceptor transfer in these binary systems.
Topological Properties of Benzenoid Systems. IX *. On the Sextet Polynomial
Authors: Gutman Ivan
Published: February 2015

A number of mathematical relations for the sextet polynomial are derived. A graph has been introduced (the so called C-graph), representing those properties of a benzenoid system which are essential in the sextet theory of Clar. The main structural properties of the C-graph are deter-mined. The obtained results contribute towards a better understanding of the algebraic and combinatorial background of Clar's theory of the aromatic sextet.
A Highly Resolved Yibronic Spectra of Dioxido-p-terphenyl and Trioxido-p-quaterphenyl in n-Hexanc at 77 K
Authors: Kawski A. , Ligȩza M.
Published: February 2015

Highly resolved vibronic absorption and fluorescence spectra of dioxido-p-terphenyl and the fluorescence spec-trum of trioxido-p-quaterphenyl in n-hexane at 77 K were obtained. The analysis of the vibrational structure in the excited singlet Si and in the ground So state gives funda-mental frequencies in the ground state in good agreement with those from infrared (IR) and Raman spectra.
Microwave Spectrum of γ-Thiobutyrolactone
Authors: Alonso José L. , Lopez J. C. , Mata F.
Published: February 2015

The microwave spectrum of γ-thiobutyrolactone has been observed and measured in the vibra-tional ground state and in several excited states of the ring-bending and ring-twisting modes. From the value of the μc component of the dipole moment and inertial-defect considerations the ring skeleton was shown to be non-planar. The average intensity ratio for the rotational transitions between the ground and excited vibrational states indicates that the first excited state of the ring-bending and ring-twisting modes are ~ 120 cm-1 and ~ 250 cm-1 above the ground state respectively. These two out-of-plane ring vibrations are essentially independent and the ring-bending vibration is governed by a nearly harmonic potential energy function. The components of the dipole moment were determined by the Stark effect to be μa = 3.770 ± 0.001 D, μb = 1.818 ± 0.044 D and μc = 0.832 ± 0.018 D, leading to μtotal = 4.268 ± 0.023 D. The rigidity of the γ-thiobutyrolactone ring is discussed in relation to those of related molecules.
Theoretical Study on the Molecular Geometries of Substituted Fluoroforms
Authors: Kiss Árpád I. , Hargittai István
Published: February 2015

The F…F non-bonded distances are strikingly constant in a large series of trifluoromethyl derivatives. Semiempirical NDDO calculations have been performed for five representative molecules. From the energy partitioning it appears that the bonding interactions (resonance energy terms) are dominating in determining the molecular geometry. The constancy of the non-bonded distances may occur as the changes in the bond lengths and bond angles are compensated. A good description of the total energy, however, necessitates the inclusion of the two-center electrostatic terms of all atom pairs.
Class Specific Physical Properties of Liquid Crystals and Correlations with Molecular Structure and Static Electrooptical Performance in Twist Cells
Authors: Schadt M. , Gerber P. R.
Published: February 2015

We made measurements of the temperature dependence of the static dielectric constants, the optical anisotropy and the three elastic constants of binary mixtures belonging to twelve structurally and physically markedly different liquid crystal classes. The class-specific material properties were quantitatively correlated with molecular structural elements. The changes of material properties occurring when different LC-classes are combined were investigated. Analytical approximations are presented which are shown to reproduce the static transmission characteristics of twisted nematic cells and their dependence on material constants and temperature with an accuracy comparable to exact numerical calculations. Strong smectic pretransitional effects are shown to influence not only k22 and k33 but also k11, thus suggesting that not only twist and bend but also splay deformations may be prohibitive in smectics. We show that the elastic ratio &33/&11 of different liquid crystal classes increases with increasing dielectric anisotropy thus leading to a decrease of the slope of transmission characteristics of twist cells. Furthermore, it is shown that k33/k11 decreases for molecules comprising heterocyclic rings whereas hydrogenation of an aromatic ring causes k33/k11 to increase.