Showing papers by "Helsinki University of Technology published in 1983"
TL;DR: This material is protected by copyright and other intellectual property rights, and duplication or sale of all or part of any of the repository collections is not permitted, except that material may be duplicated by you for your research use or educational purposes in electronic or print form.
Abstract: The Fermi-level scattering phase shifts and the transport cross sections are reported for atoms embedded in a homogeneous electron gas. The applications of the results are discussed, using the electronic stopping power for slow ions and impurity resistivity as examples.
169 citations
TL;DR: Cerebral magnetic fields evoked by painful dental stimulation indicate a current source at the upper bank of the anterior Sylvian Fissure, corresponding to the anterior end of the secondary somatosensory cortex, which suggests cortical representation of tooth pulp in man.
108 citations
TL;DR: In this paper, quantum energy levels and wave functions have been calculated for the motion of chemisorbed hydrogen atoms on Ni surfaces and the results show considerable quantum effects for the adatom in both the ground and excited states.
Abstract: Quantum mechanical energy levels and wave functions have been calculated for the motion of chemisorbed hydrogen atoms on Ni surfaces. The results show considerable quantum effects for the adatom in both the ground and the excited states. The description of the adparticles as being delocalized along the surface offers a novel interpretation of several phenomena, in particular the vibrational excitations.
107 citations
TL;DR: Cerebral magnetic fields elicited by electric stimulation of peripheral nerves were studied in man and responses seem to provide the first non‐invasive tool to study the function of SII in man.
Abstract: Cerebral magnetic fields elicited by electric stimulation of peripheral nerves were studied in man. Responses were found over the Sylvian fissure at latencies of 95-125 ms for both contra- and ipsilateral stimuli. The field distribution indicated that the responses are generated in the second somatosensory cortex SII at the upper bank of the Sylvian fissure. These responses seem to provide the first non-invasive tool to study the function of SII in man.
104 citations
TL;DR: In this article, the beam-propagation method was used to calculate both the pure bending loss and the transition loss of bent single-mode optical waveguides and fibers, which allowed the authors to establish the accuracy of several commonly used theories of bending loss.
Abstract: We demonstrate that the beam-propagation method can be used to calculate accurately both the pure bending loss and the transition loss of bent single-mode optical waveguides and fibers. Our results allow us to establish the accuracy of several commonly used theories of bending loss and to investigate the degree to which theories of step-index monomode fiber losses can be used to predict the losses of graded-index monomode fibers.
93 citations
TL;DR: In this article, the NH 2 -inversion levels in the A 1 B 2 State of aniline-NH 2 and -ND 2 have been improved using new information regarding
87 citations
TL;DR: A vast number of potential applications are already known, and one of the most interesting applications may be in continuous fermentation such as ethanol production by immobilized living microorganisms.
Abstract: Although the application of the natural attraction of many microorganisms to surfaces has been applied in vinegar production since the early 1980s, and has long been utilized in waste water purification, the development of microbial cell immobilization techniques for special applications dates back only to the early 1960s. The immobilization may involve whole cells, cell fragments, or lysed cells. Whole cells may retain their metabolic activity with their complex multienzyme systems and cofactor regeneration mechanisms intact, or they may be killed in the process with only a few desired enzymes remaining active in the final biocatalyst. Cells may also be coimmobilized with an enzyme to carry out special reactions. Although relatively few industrial scale applications exist today, some are of very large scale. Current applications vary from relatively small scale steroid conversions to amino acid production and high fructose syrup manufacture. A vast number of potential applications are already known, and one of the most interesting applications may be in continuous fermentation such as ethanol production by immobilized living microorganisms. 373 references.
78 citations
01 Jul 1983
TL;DR: This work presents an algorithm that employs a three-dimensional extendible cell (EXCELL) directory to the set operation problem, and demonstrates by practical experiments the efficiency and the local nature of the algorithm.
Abstract: Set operation algorithms form an important component of solid modeling systems. Their efficiency can be enhanced by localizing the search for geometric intersections to the region of overlap using a spatial directory. We present an algorithm that employs a three-dimensional extendible cell (EXCELL) directory to the set operation problem, and demonstrate by practical experiments the efficiency and the local nature of the algorithm.
68 citations
TL;DR: The versatility of an HTST-extrusion cooker provides possibilities for its use as a continuous chemical and/or biochemical reactor as mentioned in this paper, and it can be modified for a variety of end uses or pretreated for subsequent biotechnical applications.
66 citations
TL;DR: Positron annihilation and resistivity measurements have been performed on neutron-irradiated pure Fe, Fe−50 at ppm C and Fe-750 at ppm D in this paper, where vacancy migration is found to start at around 160 K as correlated within the collision cascades and carbon impurities have no effect on the phenomenon.
65 citations
TL;DR: The sources of auditory evoked electric and magnetic responses were modelled with multiple current dipoles and did not show any systematic dependence on the tonal frequency.
Abstract: The sources of auditory evoked electric and magnetic responses were modelled with multiple current dipoles. The activity at the auditory cortices, 2.6 cm beneath the skull, explains the observed\(\overline {N100m}\) field distribution. An additional current source near the vertex is needed to explain the corresponding potential distributions. The locations of the current sources of\(\overline {N100m}\) did not show any systematic dependence on the tonal frequency.
TL;DR: In this paper, the properties and applications of titanium nitride coatings are discussed and the use of their use for wear reduction in cutting are presented and their frictional properties are investigated.
TL;DR: In this article, it was shown that the vortex core possesses spontaneous intrinsic magnetization and that the gyromagnetic effect shows a discontinuity in magnitude at the first-order phase-transition temperature.
Abstract: Rotating superfluid $^{3}\mathrm{He}$-$B$ is found to possess a new contribution to the NMR frequency shift, which changes sign on reversal of either the angular velocity of rotation or the magnetic field. For $p=29.3$ bars this gyromagnetic effect shows a discontinuity in magnitude at the first-order phase-transition temperature $\frac{T}{{T}_{c}}=0.6$, at which a change in the vortex-core structure takes place. These observations support the conclusion that the vortex core possesses a spontaneous intrinsic magnetization.
TL;DR: In this paper, a Creusot-Loire BC 45 twin-screw high temperature short time (HTST) extrusion cooker was used with Bacillus licheniformis α-amylase (Termamyl) to saccharify barley starch.
TL;DR: The rare earth oxysulfate series Ln2O2SO4 (Ln = La, Gd, Y) was synthesized by two different thermal decomposition methods.
TL;DR: This material is protected by copyright and other intellectual property rights, and duplication or sale of all or part of any of the repository collections is not permitted, except that material may be duplicated by you for your research use or educational purposes in electronic or print form.
Abstract: Powered by TCPDF (www.tcpdf.org) This material is protected by copyright and other intellectual property rights, and duplication or sale of all or part of any of the repository collections is not permitted, except that material may be duplicated by you for your research use or educational purposes in electronic or print form. You must obtain permission for any other use. Electronic or print copies may not be offered, whether for sale or otherwise to anyone who is not an authorised user. Nieminen, R. M.; Puska, Martti
TL;DR: In this article, a rotating nuclear demagnetization cryostat was used for continuous-wave NMR experiments on superfluid3He-A and 3He-B. The measurements were performed in a long cylindrical geometry of 5 mm diameter, with the cylinder axis parallel to the axis of rotation and with the external magnetic field H 0=284 or 142 Oe in the same direction.
Abstract: We have constructed a rotating nuclear demagnetization cryostat and used it for continuous-wave NMR experiments on superfluid3He-A and3He-B. The measurements were performed in a long cylindrical geometry of 5 mm diameter, with the cylinder axis parallel to the axis of rotation and with the external magnetic field H0=284 or 142 Oe in the same direction. The angular velocity of rotation Ω was varied between 0.2 and 1.5 rad/sec, and the experiments were done under 29.3 bar pressure at temperatures between Tc=2.72 and about 1.4 mK. As a guide to the new and esoteric field of superfluid3He in rotation, we first review the general theory at some length in relatively simple terms. Pictorial explanations are often given.
TL;DR: In this article, a theory for the satellite peak in the NMR spectrum of rotating superfluid3He-A is presented, where absorption at the frequency of the satellite is produced by spin waves localized on vortex lines.
Abstract: A theory for the satellite peak in the NMR spectrum of rotating superfluid3He-A is presented. Absorption at the frequency of the satellite is produced by spin waves localized on vortex lines. The peak frequency and total intensity of the satellite are calculated for both singular and nonsingular vortices; a comparison with the Helsinki NMR data strongly suggests that nonsingular vorticity was actually observed in the experiments.
TL;DR: In this paper, it was shown that there may exist five axisymmetric vortices in space-time, different in their internal symmetries, and the Landau theory for phase transitions between them was constructed.
Abstract: It is shown that there may exist five axisymmetric vortices in $^{3}\mathrm{He}$-$B$, different in their internal symmetries. The Landau theory for phase transitions between them is constructed. Numerical calculations show that one of the observed vortices possesses a novel new structure: a superfluid core, which is ferromagnetic. This explains the measured large magnetic moment of the vortex.
TL;DR: In this article, wheat starch was liquefied as a slurry containing 60% water at 120°C mass temperature, feed rate 1 500 g min−1, screw rotation rate 250 min− 1, and 0.9% (w/w, d.s.) Novo glucoamylase 150 L to reach a DE 96 in 22 h.
Abstract: Wheat starch was liquefied to DE 25–30 employing heat stable α-amylase and twin-screw Werner & Pfleiderer Continua 58 HTST-extruder. Most significant reduction in batch saccharification time was obtained when starch was liquefied as a slurry containing 60% water at 120°C mass temperature, feed rate 1 500 g min−1, screw rotation rate 250 min−1, and 0.9% (w/w, d.s.) Novo Termamyl 120 L α-amylase was added immediately after initiation of gelatinization in the extruder. Saccharification was carried out at 60°C employing 0.36% (w/w, d.s.) Novo glucoamylase 150 L to reach a DE 96 in 22 h. Best total conversion was, however, obtained when also saccharification was initiated in the extruder by adding glucoamylase just before the die element, after lowering mass temperature to 60°C, and by allowing the saccharification to continue at 60°C after extrusion processing to reach a DE 94 in 5 h and DE 97 in 21 h.
Enzymatische Starkekonversion in einem Twin-Screw HTST-Extruder.
Weizenstarke wurde bis zu einem DE-Wert von 25–30 DE verflussigt, unter Verwendung hitzestabiler α-Amylase und unter Einsatz eines kontinuierlich arbeitenden Doppel-Schnecken-Extruders deutscher Bauart. Die im Behalter-Verfahren durchgefuhrte Starkeverzuckerung ergab eine signifikante Reduktion der Verzuckerungszeit, besonders dann, wenn die Starke als Starkemilch mit 60% Wassergehalt bei 120°C Massetemperatur, eine Einspeisungsrate in den Extruder von 1 500 g/min und einer Umdrehungszahl der Doppelschnecken von 250 U/min verflussigt wurde und man Novo-Termamyl 120 L-α-Amylase in einer Menge von 0,9% (w/w, TS) so hinzufugte, das der Eintritt des flussigen Termamyls direkt nach Beginn der Starkegelatinierung im Extruder erfolgte. Die Verflussigung der Starke wurde bei 60°C und bei Anwendung von 0,36% (w/w, TS) Novo-Glucoamylase 150 L bis zum Erreichen eines DE-Wertes von 96 in 22 h durchgefuhrt. Die beste Starkeverflussigung bzw. -verzuckerung wurde jedoch dann erreicht, wenn man die Verzuckerung durch Zugabe von Glucoamylase unmittelbar vor die Scherelemente vor der Extruderduse einpumpte und auserdem die Massetemperatur bis auf 60°C absenken konnte und Vorsorge dafur traf, das die Verzuckerung bei 60°C nach dem Extrusionsprozes kontinuierlich fortlaufen konnte, bis ein DE-Wert von 94 in 5 h und ein DE-Wert von 97 in 21 h erreicht war.
TL;DR: A variant of the original learning rule is analyzed and results are given on its application to the classification of phonemes in automatic speech recognition.
TL;DR: The main result of as mentioned in this paper is that if a is a fixed direction in a euclidean space and r is the variable vector, then the polynomials are regular in the sense of R. Delanghe, when the c...
Abstract: The main result of this paper is the following: if a is a fixed direction in a euclidean space and r is the variable vector, then the polynomials are regular in the sense of R. Delanghe, when the c...
TL;DR: The authors showed that voluntary limb movements are preceded by MEG shifts beginning even as early as 1.2 s before the movement, and these shifts reverse polarity above the cortical motor representation area of the limb concerned.
Abstract: Voluntary limb movements are preceded by MEG shifts beginning even as early as 1.2 s before the movement. These shifts reverse polarity above the cortical motor representation area of the limb concerned.
TL;DR: The average crystallite size in the films grown by atomic layer epitaxy (ALE) is about 100 nm, which is larger than that for films deposited by electron beam evaporation (EBE) by a factor of 5-10.
TL;DR: In this article, the energy of the transition 6A1 4E, 6A 1 4T2 and 4T 1 6 A1 within the 3d-shell of Mn2+ in thin films of ZnS:Mn grown by atomic layer epitaxy (ALE) are determined by luminescence spectroscopy.
Abstract: The energy of the zero-phonon-lines of the transition 6A1 4E, 6A1 4T2 and 4T1 6A1 within the 3d-shell of Mn2+ in thin films of ZnS:Mn grown by atomic layer epitaxy (ALE) are determined by luminescence spectroscopy. A comparison of these values with the energies obtained with polymorphic ZnS:Mn single crystals indicates a predominantly hexagonal structure in the thin films in fair agreement with the data obtained by X-ray-analysis. The zero-phonon-lines in both photoluminescence and high field electroluminescence of thin films are compared.
Die Energie der Nullphononenlinien der Ubergange 6A1 4E, 6A1 4T2 und 4T1 6A1 innerhalb der 3d-Schale von Mn2+ in dunnen ZnS:Mn Schichten, die durch Atomic Layer Epitaxy (ALE) gezuchtet waren, werden durch Lumineszenzspektroskopie bestimmt. Ein Vergleich dieser Werte mit den Energien, die an polymorphen ZnS:Mn Einkristallen gewonnen werden, weist auf eine vorwiegend hexagonale Struktur in den Schichten hin. Dies ist in Ubereinstimmung mit Strukturuntersuchungen durch Rontgenstrahlen. Die Nullphononenlinien der Photolumineszenz und der Hochfeldelektrolumineszenz der dunnen Schichten werden verglichen.
TL;DR: In this paper, flat-bread-like products were continuously produced on a Creusot-Loire twin-screw extrusion-cooker using wheat and rye flours of different qualities, their mixtures and unmilled whole grain as raw materials.
01 Jan 1983
TL;DR: This chapter discusses the developments in immobilized whole microbial cell-catalyzed biochemical conversions for applications in food and pharmaceutical industries and for energy and fuel production.
Abstract: Publisher Summary This chapter discusses the developments in immobilized whole microbial cell-catalyzed biochemical conversions for applications in food and pharmaceutical industries and for energy and fuel production. The concept of enzyme engineering began in the beginning of the 1970s. The first commercial application of immobilized-whole-cell technology is thought to have been steroid dehydrogenation in 1964 by Squibb. The major industrial application at present is the use of glucose isomerase for high-fructose syrup (HFS) production. Immobilized whole-cell applications may include the use of disrupted or lysed cells, cell fragments, and organelles as well as both nonviable and living cells. The majority of current industrial-scale applications are based on single-enzyme-catalyzed transformations. Immobilized whole cells have also been investigated for the production of several other organic acids. Thereafter, the application of immobilized-enzyme technology for the production of pure L-amino acids has been recognized as a major breakthrough in applied biochemistry. The applications of immobilized-yeast-cell technology in biotechnical ethanol production have also been observed more recently. Immobilized-biocatalyst technology is becoming increasingly important in medical and pharmaceutical applications. With more research into immobilized cells, other possible avenues of applications are being realized.
TL;DR: In this paper, the luminance, efficiency, threshold voltage, and voltage polarity dependence of the light emission have been investigated as a function of the ZnS:Mn layer thickness in ac thin-film electroluminescent (TFEL) devices grown by Atomic Layer Epitaxy (ALE).
Abstract: Luminance, efficiency, threshold voltage, and voltage polarity dependence of the light emission have been investigated as a function of the ZnS:Mn layer thickness in ac thin-film electroluminescent (TFEL) devices grown by Atomic Layer Epitaxy (ALE). The crystallinity of the ZnS:Mn layer was studied by X-ray diffraction. The layer of poor crystallinity is about 35 nm and coincides with the dead layer observed in luminance. Luminance is nearly proportional to the ZnS:Mn layer thickness and might indicate a homogeneous excitation throughout the layer at high voltages.
TL;DR: The problem of the existence of a stationary distribution and the convergence towards it in a certain semistochastic model for the growth of a population and a constructive method for finding the stationary distribution is given.
Abstract: The problem of the existence of a stationary distribution and the convergence towards it in a certain semistochastic model for the growth of a population is considered. It is assumed that the population grows according to a deterministic equation, but at certain times there are catastrophes, which lead to a decrease in the population level. The hazard function for the occurrence of catastrophes is a function of the population level only. The size of these jumps have a distribution that depends on the population size immediately before the catastrophe. A constructive method for finding the stationary distribution is given.