Showing papers by "University of Antwerp published in 1975"
TL;DR: A surface equation of state for polymer interfaces is obtained by equating the chemical potentials of the solvent in the bulk and surface phases and contains the fraction of the surface covered with polymer and the surface activity coefficient as parameters.
42 citations
32 citations
TL;DR: The techniques used in this survey give some new ideas concerning the structure of the Pade table and the different ways to compute the elements of the table.
19 citations
TL;DR: In this article, the rotational barrier in the N,N-dimethylamide group was studied by proton NMR for N-dimethylnicotinamide and two quaternary salts in aqueous solution.
Abstract: The rotational barrier in the N,N-dimethylamide group is studied by proton NMR for N,N-dimethylnicotinamide and two quaternary salts in aqueous solution. The carbon-13 NMR spectra of a number of aromatic N,N-dimethylamides are discussed. A roughly linear correlation is found between the ΔG≠ values of the rotation barriers and the chemical shifts of the carbon atom substituted by the amide group.
16 citations
TL;DR: It is shown that each everywhere growing DIL language is the image under a coding of an everywhere growing (uniform)DOL language, which enable us to solve the subword complexity problems for developmental languages with interactions.
Abstract: Lee has shown that ifL is aDOL language, then πink(L)
16 citations
TL;DR: 5-HTP failed to induce any long-term differences in the EM frequencies, and the drug had a short-term effect lasting up to 8 days, while an increase in muscle tone and an improvement of motor behaviour were the only long-lasting results.
15 citations
TL;DR: In this article, the aluminium rich end of the aluminium-molybdenum system has been studied by electron diffraction and electron microscopy and the defect structure of both Al 4 Mo and Al 5 Mo has been investigated.
15 citations
TL;DR: A combined mitochondrial and light mitochondrial fraction and a microsomal fraction were isolated from bovine thyroid gland and fractionated further in a B-XIV zonal rotor, resulting in the formation of a single zone at intermediate densities (agg of membranes?).
Abstract: A combined mitochondrial and light mitochondrial fraction and a microsomal fraction were isolated from bovine thyroid gland and fractionated further in a B-XIV zonal rotor. A density gradient ranging from 20 to 50% (w/w) sucrose was used. The rotor was operated for 3 h at 45 000 rev./min. All manipulations were performed at 4 degrees C and at pH 7.4. 2. Membranous material was recovered in two zones: zone I, containing microsomal material derived from both smooth endoplasmic reticulum and plasma membranes and probably also from other smooth membranes; zone II, containing material from rough endoplasmic reticulum. 3. Increasing the pH of the medium up to 8.6, or the addition of Mg2+ to the medium resulted in the formation of a single zone at intermediate densities (aggregation of membranes?). An analogous effect was obtained after treatment with Pb (NO3) 2. 4. In the presence of heparin (50 i.u./ml) the bulk of the membranes was found in zone I. This was due to the release of ribosomes from the rough endoplasmic reticulum.
13 citations
TL;DR: In this article, the energy loss function of a gas of polarons was calculated in the RPA approximation for a given number of phonon-plasmon resonances, with frequency between ω TO and ω LO.
12 citations
TL;DR: In this paper, the condition of gauge invariance for the values of the center can be used to find the $s$ mixing in the unpaired-hole orbital, and the internuclear distances of the various ${V}_{k}$ centers in alkali halides are calculated.
Abstract: It is shown that the condition of gauge invariance for the $g$ values of the ${V}_{k}$ center can be used to find the $s$ mixing in the unpaired-hole orbital. Using experimental hyperfine-structure data the internuclear distances of the various ${V}_{k}$ centers in alkali halides are calculated.
11 citations
TL;DR: In this article, two types of electrodes for the determination of ammonia are compared: one of the liquid membrane and the other of the gas detecting type, and important electrode characteristics such as response time, sensitivity and selectivity are commented.
Abstract: Two types of electrodes for the determination of ammonia are compared: one of the liquid membrane and one of the gas detecting type. Important electrode characteristics as response time, sensitivity and selectivity are commented. The ammonia electrode was tested in practice by analysis of ammonia and nitrate in canal water. The precision of the methods described was tested by analysis of synthetic samples, and by comparison with a volumetric and colorimetric method.
TL;DR: Detailed data is presented for the first time on the overall shape and size of a high molecular weight RNA molecule in the free state and it appears to be a both flat and elongate coil of about 620 A diameter and a ratio of about 1.1.
TL;DR: In this article, a secondary target tube excited x-ray fluorescence apparatus was compared with a conventional sequential wavelength dispersive spectrometer for multi-element analysis with limited precision of thin samples of environmental composition.
TL;DR: Some convergence properties of these non-linear techniques, mainly based on the use of Pade approximation and rational interpolation, given for computing the value of a definite integral are proved.
TL;DR: The peripheral vasomotor tonus seems to be influenced by yet another mechanism, independent of local catecholamine release, which depends on the balance between the degree of excitation of hypothalamic pressor (medial) and depressor (lateral) zones.
Abstract: When electrical stimulation is applied to the ventromedial hypothalamic zone one observes an increase in systemic blood pressure. There also occur blood pressure variations in the isolated femoral circuit: two distinct phenomena were observed. The early event, being either an increase or a decrease in peripheral resistance, is directly related to the amount of noradrenaline produced locally. The late event is due to catecholamines arriving from the general circulation. Inhibition of local catecholamine release through the baroreceptor reflex and inhibition of ganglionic transmission by a large and sudden increase in adrenaline blood levels do influence the response in the isolated femoral circuit. Moreover the peripheral vasomotor tonus seems to be influenced by yet another mechanism, independent of local catecholamine release. This delicate mechanism depends on the balance between the degree of excitation of hypothalamic pressor (medial) and depressor (lateral) zones.
TL;DR: The mass spectra of 4-substituted-1,2,6-trimethyl-3,5-diethoxycarbonyl and 1,4-dihydropyridines have been studied in this article.
Abstract: The mass spectra of 4-substituted-1,2,6-trimethyl-3,5-diethoxycarbonyl-1,4-dihydropyridines have been studied. The detailed fragmentation mechanisms, supported by high resolution measurements, the study of metastable ions and the use of deuterium labelling, are discussed.
TL;DR: In this article, the optical absorption of piezoelectric polarons is calculated for all values of the electron-phonon coupling, showing a series of peaks due to internal transitions of the polaron superposed on a background resulting from emission and absorption of acoustical phonons.
TL;DR: The fenestrated capillary wall showed no changes, either after withdrawal of aqueous, or after toxic parasite-action; the presence of large protein molecules and trypanosomes in the anterior chamber is due to damage to the ciliary epithelium.
TL;DR: In this paper, the ground-state energy of a Hamiltonian depending linearly on a parameter is generalized for an arbitrary dependence on that parameter, and it is shown that this inequality is satisfied under certain conditions for wave functions calculated by a variational principle.
Abstract: The inequality derived by Ferrell for the ground-state energy of a Hamiltonian depending linearly on a parameter is generalized for an arbitrary dependence on that parameter. It is shown that this inequality is satisfied under certain conditions for wave functions calculated by a variational principle. Using the generalized inequality, the ground-state energy of the bound Fr\"ohlich polaron is studied and regions in the plane of coupling constant ($\ensuremath{\alpha}, \ensuremath{\beta}$) where the inequality is violated, are determined.
TL;DR: The application of the Bayesian statistical method proves that gradient A, which takes into account the real and theoretical values of the intravascular and intraocular pressures is highly significant to evaluate the stage of deterioration of the visual field.
TL;DR: A new method is given for evaluation, in a Bayesian framework, of parameters, from which is known as prior-information that they are uniformly distributed in an interval, to eliminate autocorrelated errors, and multicollinearity in the data.
Abstract: A new method is given for evaluation, in a Bayesian framework, of parameters, from which is known as prior-information that they are uniformly distributed in an interval. The method is appropriated to eliminate autocorrelated errors, and multicollinearity in the data. The case of two bounded parameters is especially considered in estimating the Cobb-Douglas production functions. Results are commented in a non trivial example, and compared with the simular least square solution, which is not appropriated as estimation method in case of severe multicollinearity. The paper is presented in a short matrix-notation, avoiding long algebraic calculations, which can be delivred by the authors.
TL;DR: In this paper, the numerical evaluation of integrals over strongly oscillating functions of the type ∫ 0 ∞ f ( x )ϕ( x ) dx where f(x) is periodic function and where the asymptotic behaviour of ϕ (x) for large values of x is given by ϕ(x ) ∼ c x α +0( 1 x 1 +α ) with α ⩾ 1.