Showing papers by "Chalmers University of Technology published in 1969"
TL;DR: In this article, the crystal potential of the Fermi liquid is discussed and the potential from the ion cores as well as from the valence electrons, and schemes that incorporate essential exchange and correlation effects for the electrons are discussed.
Abstract: Publisher Summary: This chapter discusses two major developments that have taken place over the past decade. First is the enormous wealth of energy band calculations that have had tremendous success in explaining the properties of specific solids, but in which the connection with first principles is not always apparent. Second is the spectacular progress of many-body theory applied to the solid state that has given a number of new results, although often of a rather general and formal nature, such as to provide the justification and a formal basis for a one-electron theory. The electron gas problem is treated in some detail here. The problem of the crystal potential is given due attention. It discusses the potential from the ion cores as well as from the valence electrons, and suggests schemes that incorporate essential exchange and correlation effects for the valence electrons. An energy band calculation that properly includes the effects of exchange and correlation describes the elementary excitations called quasi particles. Quasi-particle properties are usually discussed using the remarkable Landau theory of the Fermi liquid. This chapter gives a brief presentation of the theory and reviews the present status of calculations of the Fermi liquid parameters and how they are determined from experiments. (Less)
1,042 citations
TL;DR: In this article, the short-lived isotopes of argon, krypton, silver, cadmium, tin, iodine, xenon, platinum, gold, mercury, polonium, radon and francium have been studied by the on-line isotope separator technique.
138 citations
TL;DR: In this article, it is shown that there is a characteristic momentum dependence in the energy, damping rate, and spectral weight of the quasiparticles of an interacting electron gas.
Abstract: Numerical results for some quasiparticle properties of an interacting electron gas are presented. New data are given for highly excited electrons. It is shown that there is a characteristic momentum dependence in the energy, damping rate, and spectral weight of the quasiparticle. The results are calculated using a self-energy expression to the lowest order in the effective (RPA) interaction between the electrons. Well-defined peaks in the spectrum are obtained for all momenta, and in this sense it is concluded that the quasiparticles have a physical meaning everywhere in momentum space.
Numerische Ergebnisse fur einige Eigenschaften der Quasiteilchen eines wechselwirkenden Elektronengases werden mitgeteilt und neue numerische Werte fur hochangeregte Elektronen angegeben. Wir zeigen, das eine charakteristische Impulsabhangigkeit fur die Energie, den Zerfall und das Spektralgewicht des Quasiteilchens existiert. Die Ergebnisse werden mit einem Ausdruck fur die Eigenergie in niedrigster Ordnung der effektiven (RPA) Wechselwirkung zwischen den Elektronen berechnet. Fur alle Impulse werden wohldefinierte Peaks im Spektrum erhalten, und es wird deshalb geschlossen, das die Quasiteilchen im ganzen Impulsraum physikalisch sinnvoll sind.
97 citations
TL;DR: Electron paramagnetic resonance analysis of the native and copper-depleted proteins shows that the Type 2 Cu2+ is an integral part of the laccase molecule and has a functional role in the catalytic reaction.
Abstract: 1
One of the four copper atoms of fungal laccase forms a Cu1+-chelate with bathocuproine disulfonate at pH 4.0 in 1 M guanidine hydrochloride and in the presence of excess ascorbate.
2
Electron paramagnetic resonance (EPR) analysis of the native and copper-depleted proteins has shown that one of the two Cu2+ in the protein has been removed under these conditions. The Cu2+ removed has been identified as the Type 2 or “non-blue” Cu2+. The spectral characteristics of the other Cu2+ present in the molecule (the Type 1 Cu2+) appear unchanged after removal of the second Cu2+.
3
The copper-depleted protein is almost completely devoid of enzymic activity after removal of the Type 2 Cu2+ but both the activity and original copper content can be restored after incubation of the copper-depleted protein with Cu2+ and ascorbate under anaerobic conditions. No activity is restored by the addition of Cu2+ alone.
4
The rate of removal of the Type 2 Cu2+ closely parallels the rate of decrease of enzymic activity of the protein during the reaction with the chelating agent. These results show that the Type 2 Cu2+ is an integral part of the laccase molecule and has a functional role in the catalytic reaction.
81 citations
TL;DR: The findings are consistent with the 330 nm band being associated with the two additional copper atoms in the molecule and agree with the previous suggestion that these copper atoms exist as an electron-accepting Cu2+ -Cu2+ pair in the oxidized protein.
Abstract: 1
The difference specrum between oxidized and reduced fungal laccase at pH 5.5 shows an absorption band at 330 nm in addition to the visible absorption band at 610 nm.
2
The 610 nm band and the 330 nm band are reduced together in a linear fashion with the addition of 3.5 electron equivalents of ascorbate.
3
Titration of laccase in the presence of 3 mM fluoride leads to a differentiation of the electron-accepting site in the molecule. The 610 nm band is found to be associated with a single electron-accepting site and the 330 nm band is associated with a two electron-accepting site. Electron paramagnetic resonance analysis during the titration indicates that neither the Type 1 Cu2+(the “blue” Cu2+) nor the Type 2 Cu2+ (the “non-blue” Cu2+) are associated with the 330 nm band.
4
Titration of laccase at pH 8.3 with quinol also associates the 330 nm band with a two electron-accepting site.
5
Preliminary stopped-flow kinetic measurements on the absorbance changes at 330 nm and 610 nm are described and the results suggest an involvement of the component responsible for the 330 nm band in the catalytic reaction.
6
The nature of the component responsible for the 330 nm band is discussed in the light of these results and our previous titration results. The findings are consistent with the 330 nm band being associated with the two additional copper atoms in the molecule and agree with our previous suggestion that these copper atoms exist as an electron-accepting Cu2+ -Cu2+ pair in the oxidized protein.
74 citations
TL;DR: In this article, it was shown that the critical step to bring about the transformation is for the precipitate to be cut by the moving matrix dislocation, and on this basis it is shown that there is a critical size of martensite nucleus which is only a few atoms in thickness.
72 citations
TL;DR: In this paper, the atomic-beam magnetic resonance method has been used to measure the nuclear spins of holmium and erbium isotopes with the following results: 154Ho I = 1, 155 Ho I = 5 2, 156Ho I= 1, 157 Ho I= 7 2, 158mHo I. = 5, 158mHI = 2, 159hI = 7 2 and 161hI= 3 2
61 citations
TL;DR: Trimethylsilyl ethers of alditols with 3, 4, 5 and 6 C atoms were investigated and the mass spectra were unusually clearly correlated with the structures as mentioned in this paper.
61 citations
TL;DR: The high values of the binding constants, and the fact that denaturation destroys the specific binding of zinc to alkaline phosphatase indicates chelate formation with the protein, unless some unknown prosthetic groups are involved.
Abstract: The binding of Zn2+ to Escherichia coli alkaline phosphatase has been studied by pH titrations and equilibrium dialysis using 1,10-phenanthroline as competing chelating agent.
Measurements of the strength of binding under different experimental conditions have been performed:
1
At constant pH with different concentrations of chelating agent.
2
At different pH with constant concentration of chelating agent.
3
In the presence of denaturing agent at pH 8.0.
It was found on the basis of equilibrium dialysis experiments that the binding of the two zinc atoms to alkaline phosphatase may be described as coordination to the two equivalent and independent sites.
The high values of the binding constants, and the fact that denaturation destroys the specific binding of zinc to alkaline phosphatase indicates chelate formation with the protein, unless some unknown prosthetic groups are involved.
51 citations
TL;DR: In this article, a complete band gap extending to about 2 eV above the vacuum level in the electron energy band structure for copper diffraction beams is presented. But the authors do not consider the effect of atomic scattering on the intensity curves.
51 citations
01 Jul 1969
TL;DR: In this article, the coupling of metallic core electrons to the density fluctuations of the conduction electrons is studied, and the possible implications on X-ray photoemission, soft Xray emission and absorption, and inelastic scattering of electrons are drawn.
Abstract: The coupling of metallic core electrons to the density fluctuations of the conduction electrons is studied. Due to the strong electron-plasmon coupling there is a characteristic satellite structure in the core electron spectrum, starting at the plasma energyħω p below the quasiparticle level and with a maximal spectral weight at (1.6–2.5)×ħω p below the same level. The total spectral weight in the satellite band is 50–100 percent of the quasiparticle weight, the actual value dependent on the density of the conduction electrons. The possible implications on X-ray photoemission, soft X-ray emission and absorption, and inelastic scattering of electrons are drawn. Particularly, a close correspondence with the location of the fine structure of the L2,3 absorption spectrum of Al is found. The relation to the cohesive energy is also considered.
TL;DR: In this article, the level crossing method has been used for the investigation of the hyperfine structure of the 6p2P3/2 and 7p2PC/2 levels of the isotopes Cs133, Cs135, and Cs137.
Abstract: The level crossing method has been used for the investigation of the hyperfine structure of the 6p2P3/2 and 7p2P3/2 levels of the isotopes Cs133, Cs135, and Cs137. For the hyperfine coupling constants a and b and for the lifetimes Τ we find: a(6p Cs133)=50.72(3) gJ/−1.345, b(6p Cs133)=−0.38(18) gJ/−1.345 a(7p Cs133)=16.610(6) gJ/−1.3349, b(7p Cs133)=−0.15(3) gJ/−1.3349 a(6p Cs135)=53.64(4) gJ/−1.345, b(6p Cs135)=7.41(32) gJ/−1.345 a(7p Cs135)=17.570(6) gJ/−1.3349, b(7p Cs135)=2.35(7) gJ/−1.3349 a(6p Cs137)=55.80(4) gJ/−1.345, b(6p Cs137)=7.54(20) gJ/−1.345 a(7p Cs137)=18.274(6) gJ/−1.3349, b(7p Cs137)=2.37(4) gJ/−1.3349 (MHz), Τ(6p2P3/2)=29.7(2) −1.345/gJ ns, Τ(7p2P3/2)=135(1) −1.3349Jns. From a comparison with double resonance results the gJ factor of the 7p2P3/2 level was deduced: gJ(7p2P3/2=−1.3349(10). Level crossing measurements in the 8p2P3/2 state of Cs133 give for the gJ factor and the lifetime the following results: gJ(8p2P3/2)=−1.3353(14), Τ(8p2P3/2)=310(15) ns. Using recently calculated relativistic correction factors and applying corrections for core polarization and the Sternheimer effect, we obtain for the quadrupole moments: Q(Cs133)=−0.0030 b, Q(Cs135)=+0.052 b, Q(Cs137)=+0.052 b.
TL;DR: In this paper, a comparison with dispersion curves calculated by Nusslein and Schroder for their "breathing shell" variant of the shell model for ionic crystals is made.
Abstract: Phonon dispersion relations in KCl at 80°K have been determined using inelastic neutron scattering. The measurements have been performed mainly in the symmetry directions [100], [110], and [111], but also at some other points in the reciprocal space. More than one third of the phonons in all branches were also studied at 300°K in order to obtain and estimate of the temperature dependence of their frequencies. A comparison is made with dispersion curves calculated by Nusslein and Schroder for their “breathing shell” variant of the shell model for ionic crystals. The agreement for the dispersion curves is quite satisfactory in the most cases.
Die Dispersionskurven der Gitterschwingungen in KCl bei 80°K wurden durch inelastische Neutronenstreuung gemessen. Die Messungen wurden meistens in den kristallographischen Symmetrierichtungen [100], [110] und [111], aber zum Teil auch in anderen Punkten im reziproken Raum durchgefuhrt. Mehr als ein Drittel der Phononen sind auch bei 300°K untersucht worden, um die Temperaturabhangigkeit ihrer Frequenzen zu erhalten. Die Ergebnisse werden mit dem „breathing shell”-Modell von Nusslein und Schroder verglichen. Die Ubereinstimmung ist in den meisten Fallen sehr befriedigend.
TL;DR: In this article, myoelectric signals in control of prosthesis were used to assist arm amputees and normal individuals in the control of their prosthetic devices in a controlled manner.
Abstract: (1969). Myoelectric Signals in Control of Prostheses: Studies on Arm Amputees and Normal Individuals. Acta Orthopaedica Scandinavica: Vol. 40, No. sup124, pp. 1-83.
TL;DR: In this article, an increase in flow stress in ZnO under illumination was observed and a model was proposed for the explanation of this effect and measurements of the effect were presented.
TL;DR: In this paper, the energy distribution of photoemitted electrons from CuMn and AgMn was measured and the existence of virtual bound levels of one spin direction lying between the silver 4 d band and the Fermi level was confirmed.
TL;DR: In this paper, the authors used the Westerhout catalogue of sources around the galactic plane measured at the frequency 1,390 MHz to search for more microwave sources in the H II regions.
Abstract: ALL radio observational work on OH has so far been concentrated on previously known astronomical objects. Initially the OH microwave radiation was found absorbed in the spectra of strong continuum sources1, but in the search for more OH absorption lines weaker and weaker continuum sources were investigated. The guide in this search was the source catalogue made by Westerhout2, which contains sources around the galactic plane measured at the frequency 1,390 MHz. Many of these sources have a thermal spectrum and therefore are associated with H II regions. Because the first OH emission sources were found in or near some of these H II regions3,4, the search for more OH emission was carried out chiefly on thermal radio sources. Many new OH emission sources were found in this way and theories of maser action in OH associated with H II regions were produced5,6.
TL;DR: An automatic method for the determination of acids containing two or three carboxyl groups was described in this paper, where the acids were separated on an anion-exchange resin with magnesium acetate as the eluant and determined colorimetrically by chromic acid oxidation.
TL;DR: A miniaturized transducer for intravascular measurements of pressure variations has been developed that consists of a sensor in the form of a pneumatic chamber coupled by light fiber optics to a gallium arsenide diode light source and a silicon diode detector or a phototransistor.
Abstract: A miniaturized transducer for intravascular measurements of pressure variations has been developed. The probe has an outer diameter of 1·0–1·5 mm. Its frequency response is 0 to more than 200 Hz.* It consists of a sensor in the form of a pneumatic chamber with a mirror wall coupled by light fiber optics to a gallium arsenide diode light source and a silicon diode detector or a phototransistor. Experimental tests on dogs and humans have been made.
TL;DR: In this paper, the photoemission spectra of gold films were measured and it was found that structure associated with the 5D states cannot be explained in terms of nondirect transitions.
TL;DR: In this article, the authors examined the validity of the (g. b)s method for determining the sign of the Burgers vector of a dislocation loop in the case where the dislocation is a partial and where g. b is in general not equal to unity.
Abstract: The validity of the (g. b)s method for determining the sign of the Burgers vector of a dislocation loop is examined theoretically in the case where the dislocation is a partial and where g. b is in general not equal to unity. The case g. b=± 4/3 is examined in detail and the theoretical predictions are confirmed by a contrast analysis of Frank vacancy loops in quenched aluminium. The impossibility of using the (g. b)s method under conditions for which g. b= ± 1/3 or ± 2/3 is pointed out. An alternative method of determining the sign of the Burgers vector when g. b= ± 2/3 is suggested.
TL;DR: GamGamma rays from thermal neutron capture in fluorine have been measured with Ge(Li) spectrometers and about 50 of the 80 lines observed have been tentatively fitted into the 20F decay scheme.
TL;DR: In this article, the energies and intensities of thermal-neutron capture gamma rays from 28Al have been measured by means of a Ge(Li) pair spectrometer and anti-Compton spectrometers.
01 Dec 1969
TL;DR: In this article, the reliability of Kramers-Kronig analysis on reflectance data has been investigated based on an analytical model and it is shown that the errors due to the "unmeasured region" can be reduced to acceptable values.
Abstract: To date all estimates of the errors introduced by application of Kramers-Kronig analysis to reflectance data have been based solely on experimental values. This paper presents an investigation based on an analytical model, whereby the reliability of the method can be calculated exactly. It is shown that the errors inɛ2 due to the “unmeasured region” can be reduced to acceptable values. The method of fitting the results to known optical constants gives errors inɛ2 of the order of 0.05 or less for the most commonly used extrapolation procedure, and 0.01 or less for more refined approximations. This corresponds to a precision in the reflectance determination of the order of 0.5% and 0.1% respectively.
TL;DR: In this paper, the Brillouin zones of the ordered and disordered phases of AuCu 3 have been discussed in terms of different BrillouIN zones of two phases. And an extra peak in the density of states located at 3.4 eV above the Fermi level and present only in the ordered phase has been observed.
TL;DR: In this article, the isomerization products from the treatment of D-glucuronic acid in an aqueous solution of pH 7 at 100 and 110C have been separated by anion exchange chromatography and identified.
TL;DR: In this paper, the energies and intensities of thermal-neutron capture γ-rays from 26 Mg have been measured with a Ge(Li) detector in pair and anticoincidence spectrometer arrangements.
TL;DR: Some physiological aspects of this type of plethysmography are discussed which illuminate the difficulty in discriminating between skin-flow and muscular flow and a detailed calculation of the elastic influences follows and shows that one cannot generally expect a cancellation of these influences when comparing measurements with the calibration.
Abstract: A short introductory treatment of the basic theory of the mercury strain-gauge plethysmograph is presented. Some physiological aspects of this type of plethysmography are then discussed which, among other things, illuminate the difficulty in discriminating between skin-flow and muscular flow. A detailed calculation of the elastic influences follows and shows that one cannot generally expect a cancellation of these influences when comparing measurements with the calibration. This part illuminates further the difficulties in discriminating between skin-flow and muscular flow. As a result, such discrimination should be regarded as dubious. Some other sources of error are also discussed briefly. Two proposals for a new design are given. Finally, the Appendix shows the values of the gauge stretch which will give cancellation of the elastic errors in a simple model. The actual values cannot be used in practice but they indicate that the amount of stretch is quite critical.
TL;DR: Isotopic enrichment of several percent has been obtained in liquid lithium metal by applying a temperature gradient over a single-stage separation column.
Abstract: Isotopic enrichment of several percent has been obtained in liquid lithium metal by applying a temperature gradient over a single-stage separation column For other metals the method should have the highest eficiency, if these have low melting points and are liquids over a wide temperature range