Showing papers by "Technical University of Dortmund published in 1974"
TL;DR: In this paper, the interference of two widely separated coherent neutron beams produced by dynamical diffraction in a perfect Si-crystal has been observed, and phase shifting material inserted in the beams results in a marked intensity modulation behind the interferometer.
400 citations
TL;DR: In this article, the inelastic scattering of the electrons of an impure metal by a screened Coulomb interaction is investigated, and it is found that the rate of such an ine cient scattering is increased which can be explained by a loss of momentum conservation which in turn results from loss of translational symmetry introduced by the defects of impure metals.
Abstract: The inelastic scattering of the electrons of an impure metal by a screened Coulomb interaction is investigated. It is found that the rate of such an inelastic scattering is increased which can be explained by a loss of momentum conservation which in turn results from loss of translational symmetry introduced by the defects of an impure metal. Eventually, a linearised Boltzmann equation is derived for time and space dependent perturbances of the electronic distribution function. The collision integral takes into account impurity scattering as well as electron-electron and electron-phonon scattering. In an impure metal the terms corresponding to the last two processes are modified as discussed above and in a previous paper on the electron-phonon interaction.
147 citations
98 citations
TL;DR: In this article, two widely separated coherent neutron beams from dynamical diffraction in a perfect Si-crystal are used for neutron interferometric measurements, where Al and Bi samples cause phase shifts within the individual beams which result in a marked intensity oscillation of the interfering beams behind the E-shaped interferometer crystal.
Abstract: Two widely separated coherent neutron beams from dynamical diffraction in a perfect Si-crystal are used for neutron interferometric measurements. Al and Bi samples cause phase shifts within the individual beams which result in a marked intensity oscillation of the interfering beams behind theE-shaped interferometer crystal. With this interferometer interesting features of various physical quantities can be investigated in a new way, e.g. refracting index, scattering amplitudes, magnetic domain structures, density inhomogeneities, and coherence properties of the neutron beams.
43 citations
TL;DR: In this paper, a system for the calibration of the absolute spectral response of spectrometers is described using a standard reflector -of the type used especially for colour measurements - as a secondary light source.
Abstract: A system for the calibration of the absolute spectral response of spectrometers is described using a standard reflector - of the type used especially for colour measurements – as a secondary light source. In contrast to conventional light sources for calibrations, the radiance is approximately constant over the whole area of the source, and the angular characteristic is known for a large range of reflection angles φ. A special advantage is that the angular characteristic follows closely the Lambert-cosine-jaw in the region φ∼45°. The radiant flux can be calculated exactly for various experiemental conditions, especially for Raman spectroscopy.
38 citations
TL;DR: In this article, a single-crystalline X-ray analysis of compounds with a Covalent Metal-Metal Bond was carried out, in which the Mn atoms of the two Mn(CO)5 ligands have a trans-configuration with respect to the plane of the M2Mn2-metal ring.
Abstract: Die Titelverbindungen sind isomorph. Die Molekule Mn2(CO)8{μ-MMn(CO)5}2 (M = Ga, In) zeigen im Aufbau keine wesentlichen Unterschiede. Sie enthalten einen ebenen M2Mn2-Metallring, in dem der MnMn-Abstand [Ga: MnMn = 3.052 (1) A; In: MnMn = 3.227 (1) A] und der spitze Winkel am Bruckenatom Ga bzw. In [MnGaMn = 76.86 (2)°, MnInMn = 76.36 (2)°] eine Bindung zwischen den Manganatomen erkennen lassen. Die Mn-Atome der beiden Mn(Co)5 Liganden liegen in trans-Stellung zur M2Mn2-Ringebene vor. Die Mittelwerte der ubrigen Bindungsabstande betragen: GaMn = 2.451 (1) A, InMn = 2.605 (1) A, MnC = 1.842 (5) A und MnC = 1.804(4) A, CO = 1.144(7) A.
Single-Crystal X-Ray Analysis of Compounds with a Covalent Metal-Metal Bond, I The Molecular and Crystal Structure of Octacarbonyl-bis[μ(pentacarbonylmanganese)-gallium(III)]-dimanganese and Octacarbonyl-bis[μ-(pentacarbonylmanganese)indium(III)]-dimanganese
The title compounds are isomorphous. The molecules Mn2(CO)8{μ-MMn(CO)5}2 (M = Ga, In) show no essential differences in structural pattern. They contain a planar M2Mn2 ring, in which the MnMn distance [Ga: MnMn = 3.052 (1) A, In: MnMn = 3.227 (1) A] and the acute angle at the bridging atom Ga or In [MnGaMn = 76.86(2)°, MnInMn = 76.36(2)°] are consistent with the existence of a MnMn bond. The Mn atoms of the two Mn(CO)5 ligands have a trans-configuration with respect to the plane of the M2Mn2-metal ring. The mean values for the remaining bond distances are: GaMn = 2.451 (1) A, InMn = 2.605 (1) A, MnC = 1.842 (5) A, and MnC = 1.804(4) A, CO = 1.144 (7) A.
37 citations
TL;DR: In this paper, the change asymmetry in semi-leptonic kaon decays has been measured as a function of the kaon lifetime and high statistics data of K e3 0 and K μ3 0 decay modes agree with each other and with the general expectation of the CP violation phenomenology together with the ΔS − ΔQ rule.
32 citations
TL;DR: In this article, a procedure for minimising the threshold-voltage sensitivity of implanted m.o.s. transistors due to these parameters for a typical set of process parameters is presented.
Abstract: Adjustment of the threshold voltage VT by ion implantation yields a certain distribution of threshold voltages determined by different process parameters. A procedure is presented for minimising the threshold-voltage sensitivity of implanted m.o.s. transistors due to these parameters for a typical set of process parameters.
31 citations
TL;DR: In this article, a planar bridged ring of 2M and 2 Mn atoms was shown to be isomorphous, in which 2 Mn(CO) 4 groups formed the MnMn bond, each being connected with 2 [μ-MMn(C) 5 ] units.
27 citations
TL;DR: In this paper, the K0 mass difference between two regenerators was measured by the two regenerator method and the result was: Δm = mKL − mKS = (0.534 ± 0.003) × 1010 sec−1.
23 citations
TL;DR: In this article, the stability of compounds R3CdHg-MR-3 (R = Si, Ge, Sn) to heat and light was discussed and the conditions for the occurrence of symmetrisation reactions were investigated.
TL;DR: In this article, the energy bands of the simple cubic intermetallic compound YZn have been calculated by using the APW method and the resulting Fermi surface is exhibited and shown to be fully in agreement with the results of a recent de Haas-van Alphen experiment.
Abstract: Energy bands of the simple cubic intermetallic compound YZn have been calculated by using the APW method. The crystal potential (constructed in the muffin-tin approximation from overlapping atomic charge densities and full Slater exchange) was adjusted slightly and a larger set of basis functions was used than in a previous calculation. The resulting Fermi surface is exhibited and shown to be fully in agreement with the results of a recent de Haas-van Alphen experiment.
TL;DR: In this paper, the reaction of t-butyl(trimethylsilyl)mercury with benzylidenemalonodinitrile gives N -trimethyltin hydride; other compounds RHgSiMe 3 do not react.
TL;DR: In this article, a novel complex RClSntrid, where R is Me, Ph, n-Oct, and trid 2− are dianions of tridentate “planar” ligands with ONO and SNO donor atoms, was synthesized and investigated in the solid state by infrared and Mossbauer spectroscopy.
01 Jan 1974
TL;DR: The Dienstdauervorschrift sowie weitere Einzelvorschriften, die die Arbeitszeit des Lokomotivpersonals der Deutschen Bundesbahn regeln, werden einer eingehenden ergonomischen and arbeitsmedizinischen Analyse unterzogen.
Abstract: Die Dienstdauervorschrift sowie weitere Einzelvorschriften, die die Arbeitszeit des Lokomotivpersonals der Deutschen Bundesbahn regeln, werden einer eingehenden ergonomischen und arbeitsmedizinischen Analyse unterzogen. Hierbei wird die Sachgerechtheit der Vorschriften beurteilt. Spezielle Vorschlage fur eine anderung der Dienstdauervorschrift werden unterbreitet, erganzende allgemeine Vorschlage fur zusatzliche organisatorische Masnahmen gemacht.
TL;DR: In this paper, direct one-bond tin coupling constants have been measured in a series of hexaorganoditins; the magnitude of the coupling shows a marked dependence on the effective nuclear charge on tin.
TL;DR: In this article, the IR spectra of several alkali sulfates doped with Cs 2 50 CrO 4,Cs 2 53 CrO4, Na 2 92 MoO 4 and Na 2 100 MoO4 have been measured and force constants have been calculated from isotope shift of the ν 3 (F 2 ) vibration.
TL;DR: In this paper, a relation between the behaviour of pseudo-analytic functions on C (Holder-continuity) and the degree of approximation of w(z) by pseudopolynomials is established.
Abstract: In the theory of pseudoanalytic functions one can define (pseudoanalytic) rational functions, especially polynomials called “pseudopolynomials”. (See Bers [3], [4], Vekua [12]) Therefore it can be developed a theory of approximation and interpolation by rational functions. First results have been published by Bers [3] (Runge's theorem), Ismailov and Taglieva [8]. Let G be a domain of the complex plane bounded by a closed Jordan curve, let w(z) be pseudoanalytic in G. In this paper we deal with a relation between the behaviour of w(z) on C (Holder-continuity) and the degree of approximation of w(z) by pseudopolynomials. The results correspond to certain theorems of Curtiss, Sewell and Walsh in the theory of analytic functions.
TL;DR: In this paper, a trifluormethyljod-difluorid is bildet with Acetonitril, Pyridin and Chinolin 1:1-Komplexe, die mit zunehmender Donorwirkung der N-basen stabiler werden.
TL;DR: In this article, the magnetization and shear modulus of the vortex lattice were calculated for various values of the Ginzburg-Landau parameter κ and of the film thickness.
Abstract: On the basis of the Ginzburg-Landau free energy, the magnetization and the shear modulus of the vortex lattice is calculated for various values of the Ginzburg-Landau parameter κ and of the film thickness. Agreement is found with recently measured values of the shear modulus.
TL;DR: In this article, the existence of a bound state can be proved under the following assumptions: the system can be described as a polaronic threeparticle system, the two-particle interactions are of Haken's type.
Abstract: An electron-exciton process is considered for arbitrary positive electron and hole masses. The existence of a bound state can be proved under the following assumptions: The system can be described as a polaronic three-particle system, the two-particle interactions are of Haken's type.
Es wird gezeigt, das unter bestimmten Voraussetzungen Elektron und Exziton bei beliebjgen positiven Massen von Elektron und Loch einen gebundenen Zustand bilden konnen. Die Bedingung dafur ist, das das System als Drei-Polaronen-System beschrieben worden kann, in dem die Zweiteilchenwechselwirkungen vom Hakenschen Typ sind.
TL;DR: In this paper, the authors studied the reaction of O-Stannyl and O-Silylsemidiones to the semitrione anion-radical 16 and the six-membered ring 14.
Abstract: Semidione RC˙(OMMe3)–COR, M = C, Si, Sn, R = Ph, Me, entstehen aus Radikalen MMe3˙ und Benzil bzw. Biacetyl. M = Sn bedingt Pentakoordination mit der zweiten Carbonylgruppe und damit die cis-Strukturen 2c bzw. 4. 2c reagiert mit weiterem Me3Sn˙ einheitlich zum cis-Bis(stannyloxy)stilben 7. Mit M = Si liegt dagegen die trans-Form 11 vor, weiters Me3Si˙ fuhrt ausschlieslich zum trans-Bis(silyloxy)stilben 10. Analog bildet 1,3-Diphenylpropantrion mit Me3Sn˙ nicht das Semitrion-Anion-Radikal 16 oder den Sechsring 14, sondern das Sn-haltige Funfring-Semidion 15. ESR-Daten der beschriebenen Radikale werden angegeben.
Formation and Reactions of O-Stannyl and O-Silylsemidiones
Semidiones RĊ(OMMe3)–COR, M = C, Si, Sn, R = Ph, Me, are formed from radicals MMe3˙ and benzil or biacetyl, respectively. M = Sn produces, by pentacoordination with the second carbonyl group, the cis-structures 2c or 4, respectively. 2c reacts with additional Me3Sn˙ uniformly to the cis-bis(stannyloxy)stilbene 7. With M = Si, however, the trans-structure 11 is preferred. Further reaction with SiMe3˙ gives only the trans- bis(silyloxy)-stilbene 10. Starting from 1,3-diphenylpropanetrione and Me3Sn˙, we observed neither the semitrione anion-radical 16 nor the six-membered ring 14, but the Sn-containing five-membered semidione 15. E.s.r. data of the described radicals are given.
TL;DR: In this article, the authors present a set of Untersuchungen an 111 untrainierten Kindern in the Alter of 6 bis 10 years, in which the Fuskurbellange and Sattelhohe were chosen as optimalwerte.
Abstract: Fur das Kindesalter fehlen weithin Daten, die die Relation der biologischen Leistungen am Ergometer zu Drehzahl, Kurbellange und Sattelhohe anzeigen Um solche Untersuchungen bereits bei kleineren Kindern vornehmen zu konnen, wurden fur ein vorhandenes Universalergometer Zusatzteile entwickelt und gebaut Bei diesen Untersuchungen an insgesamt 111 untrainierten Kindern im Alter von 6 bis 10 Jahren konnten als Optimalwerte fur die Fuskurbellange — bei einer Belastung von 1,5 bzw 2 Watt/kg Korpergewicht — 14 cm bei den 6jahrigen, 15 cm bei den 8jahrigen und 16 cm bei den 10jahrigen Jungengruppen und eine Drehzahl von 50 U/min fur alle diese Altersgruppen als optimal ermittelt werden
TL;DR: In this article, the Hamiltonian H0 + Hp for a perturbed bound state problem is separated in a self-consistent way into a new exactly solvable part H0v and a new perturbation Hvp.
Abstract: The Hamiltonian H0 + Hp for a perturbed bound state problem is separated in a self-consistent way into a new exactly solvable part H0v and a new perturbation Hvp. Perturbation theory on H Hpv leads in many cases to a better converging result compared to Hp Especially the calculations of the phonon- and anisotropy-influence on the bound exciton states compare satisfactory with experimental data and with results of involved variational methods. This good agreement is achieved by a partial summation of important parts of all higher order perturbation terms of Hp, without using any free parameters.
Der Hamiltonoperator H0 + Hp eines gestorten gebundenen Zustandes wird selbstkon-sistent in einen neuen, exakt losbaren Anteil H0v, und eine neue Storung Hpv aufgespalten. Die Storungsrechnung bezuglich Hpv ergibt besser konvergierende Ergebnisse als die Storungsrechnung mit Hp. Insbesondere ergibt die Storungsrechnung erster Ordnung in Hpv fur den Phononen- und Anisotropieeinflus auf gebundene Exzitonenzustande Resultate, die mit den experimentellen Daten und mit umstandlichen Variationsrechnungsergebnissen gut ubereinstimmen. Diese gute Ubereinstimmung wird durch eine Partialsummation nichtiger Anteile aller Beitrage hoherer Ordnung bezuglich Hp erreicht, ohne das ein freier Parameter verwendet wird.
TL;DR: In this article, a konvergierende Stromung in der Einlaufzone von Keilspaltdusen realisiert is presented, das je nachdem, ob die Scherentzahung im Stoffverhalten uberwiegt oder nicht.
Abstract: Es wird die Stromung einer einfachen viskoelastischen Flussigkeit zwischen zwei ebenen festen Wanden, die einen Winkel miteinander bilden und langs deren Schnittgeraden Senken verteilt sind, untersucht. Eine konvergierende Stromung dieser Art wird naherungsweise in der Einlaufzone von Keilspaltdusen realisiert. Es wird gezeigt, das je nachdem, ob die Scherentzahung im Stoffverhalten uberwiegt oder nicht, die Sekundarstromung aus zwei an den Kanalwanden anliegenden Zonen besteht, oder aus einer Zone in der Kanalmitte.
TL;DR: In this paper, the phase φ+− is evaluated on the basis of measurements of the KS-KL interference in the π+π− decay mode and the mass difference Δm, both reported previously by this group.
TL;DR: In this paper, the i.r. spectra of the planar [ 58 Ni(CS 3 ) 2 ] 2− ion and its 62 Ni analog have been assigned based on observed isotopic shifts due to the 64 Zn-68 Zn substitution.