Showing papers by "Philips published in 1971"

Theory of Radiative Heat Transfer between Closely Spaced Bodies

Abstract: A general formalism is developed by means of which the radiative heat transfer between macroscopic bodies of arbitrary dispersive and absorptive dielectric properties can be evaluated. The general formalism is applied to the heat transfer across a vacuum gap between two identical semi-infinite bodies at different temperatures. The peculiarities arising when the gap width is of the order of, or smaller than, the dominant thermal radiation wavelengths are studied and quantitatively evaluated for the case of two metal bodies. The predicted strong increase with diminishing gap width is in qualitative agreement with experimental results.

Effect of hydrodynamic interaction on the coagulation rate of hydrophobic colloids

Abstract: The hydrodynamic interaction which occurs when particles are close to each other diminishes the coagulation rate of colloidal particles. We have evaluated this effect, improving a previous treatment by Derjaguin and Muller (7). The absolute rate of rapid coagulation has been computed numerically, with the help of the complete Hamaker equation for the van der Waals force. We have found that hydrodynamic interaction diminishes this rate by a factor of about 0.4 to 0.6, depending on the Hamaker constant. This result agrees completely with that of Spielman (8). The ratio W of the rates of rapid and slow coagulation has been calculated analytically with a simplified Hamaker equation and an approximate expression for the double-layer interaction, following, with modifications, the procedure of Reerink and Overbeek (21). The factor W has also been computed by numerical integration with the complete Hamaker equation. In either calculation the effect of hydrodynamic interaction on d(ln W ) /d (ln c e ) (where c e is the concentration of indifferent electrolyte) is found to be small. We conclude, in agreement with Derjaguin and Muller, that the existing discrepancy between theory and experiment with regard to d(ln W )/d (ln c e ) cannot be explained by this hydrodynamic effect.

A Molecular Theory of the Cholesteric Phase and of the Twisting Power of Optically Active Molecules in a Nematic Liqud Crystal

Abstract: The molecular properties of optically active molecules are used to extend the molecular statistical theory of the nematic phase in order to explain the helical structure of the cholesteric phase. In order to account for these properties the dispersion energy between two molecules is calcualted taking into account not only the dipole-dipole interaction but also the dipole-quadraupole interaction. The calculated twist thas the right order of magnitude. The theory moreover explains the twisting power of optically active solute molecules in a menatic solvent and also the concentration dependence of the induced twist angle. A consequence of this theory is that the helical structure only exists, if the distribution of orientations around the long molecular axes is not rotationally symmetric; one may expect this to be the case for e.g. planar molecules.

Characterization of low 1/f noise in MOS transistors

Abstract: By careful processing MOS transistors have been fabricated with a low value of the interface states density (2 × 1010/cm2eV). Consequently the 1/f noise in these devices is low and in the same order of magnitude as for junction FETs. The experimental values of the equivalent noise voltage and the equivalent noise current are compared to an expression derived from straight physical arguments. From the comparison it is concluded that the noise equivalent voltage in saturated operation is proportional to the effective gate voltage, the interface state density, and inversely proportional to the gate input capacitance. Moreover, it is concluded that a proper heat treatment not only reduces the number of states but also removes the near bandedge peaks, which usually appear in the trap distribution function.

Ellipsometry of Anisotropic Films

Abstract: The macroscopic description of the optical behavior of (thin) films adsorbed on a polished solid surface is extended by allowing for uniaxial anisotropy in the adsorbate. The theoretical results are applied to Langmuir–Blodgett layers of absorbing and nonabsorbing surface-active compounds.

Intermetallic compounds of rare earth elements and Ni, Co, or Fe

Abstract: A survey is given of the composition and crystal structure of existing rare earth transition intermetallics. The relationship in crystal structure of the compounds RM2, RM3, R2M7, RM5, and R2M17 is briefly discussed (R and M represent a rare earth and 3d element, respectively). The variation of the magnetic moment of the M atoms and the variation of the Curie temperature brought about by the increase of the molar fraction of the rare earth element in the various compounds is different for M being Ni, Co, or Fe. An attempt has been made to explain these differences by means of Friedel's model of d-bands in transition metals. The R–M spin interaction is antiferromagnetic and leads in general to compensation points in the magnetization versus temperature curves. It is shown that these compensation points should vary with R as g (g − 1) J (J + 1). This relation is obeyed for the compounds RFe3 for which magnetic data and the lattice constants are given. A mechanism for the R–M exchange interaction is proposed. Magnetic data are also given for the compounds GdGa and GdGa0.7Cu0.3 isostructural with GdNi. Es wird ein Uberblick uber Zusammensetzung und Kristallstruktur der existierenden intermetallischen Verbindungen zwischen Seltenen Erden und Ubergangsmetallen gegeben. Die Beziehungen zwischen den Kristallstrukturen der Verbindungen RM2, RM3, R2M7, RM5 und R2M17 werden kurz diskutiert (R Seltene Erde, M Ubergangsmetall). Die Anderung des magnetischen Moments der M-Atome und die durch die Erhohung des Anteils der Seltenen Erdelemente in den verschiedenen Verbindungen bewirkte Anderung der Curie-Temperatur ist fur Ni, Co und Fe unterschiedlich. Diese Unterschiede werden mittels des Friedel-Modells der d-Bander in Ubergangsmetallen zu erklaren versucht. Die R–M-Wechselwirkung ist antiferromagnetisch und fuhrt im allgemeinen zu Kompensationspunkten in den Magnetisierungs–Temperatur-Kurven. Diese Kompensationspunkte sollten mit R wie g (g − 1) J (J + 1) variieren. Diese Beziehung gilt fur die Verbindungen RFe3, fur die magnetische Daten und Gitterkonstanten angegeben werden. Ein Mechanismus fur die R–M-Austauschwechselwirkung wird vorgeschlagen. Magnetische Daten werden auch fur die Verbindungen GdGa und GdGa0,7CU0,3, die, die gleiche Struktur wie GdNi haben, angegeben.

The effect of normal blowing on the flow near a rotating disk of infinite extent

Abstract: The effect of blowing through a porous rotating disk on the flow induced by this disk is studied. For strong blowing the flow is almost wholly inviscid. First-order viscous effects are encountered only in a thin layer at some distance from the disk. The results of an asymptotic analysis are compared with numerical integrations of the full equations and complete agreement is found.

Calculation of intrinsic coercivity of magnetic domain walls in perfect crystals

Abstract: The critical field strength at which a classical domain wall moves through a perfect ferromagnetic crystal of simplified structure is calculated as a function of the ratio between anisotropy energy K and ferromagnetic coupling energy C , taking into account the discrete nature of the spins. When K approaches C intrinsic wall pinning becomes appreciable with critical fields approaching the anisotropy field when K \gg C . For K/C \geq 2/3 , the wall has a thickness of one atomic distance and thus resembles a ferroelectric wall.

Sorption hysteresis in the LaNi5-H and SmCo5-H systems

Abstract: The pressure-composition isotherms of the SmCo5-H and LaNi5-H systems have been measured for absorption as well as desorption. In the two-phase region of these systems, hysteresis is found to occur. It is argued that the magnitude of the hysteresis is related to the rather large volume expansion which accompanies the formation of the hydride.

Tables and equations of the diffuse double layer repulsion at constant potential and at constant charge

Abstract: Tables are presented of the repulsive energy due to the interaction of diffuse double layers. The cases of two parallel flat plates and of two spheres are considered both at constant equal surface potential and at constant equal surface charge. The radii of the spheres are assumed to be large compared with the thickness of the double layer ( κa ⪢ 1). Limiting equations are presented for four different cases: small separations, large separations, moderate potentials, and moderate charge densities. The ratios of the flocculation concentrations for mono-, di-, and trivalent ions are computed also, both for constant potential and for constant charge.

On the origin of the maximum in the electromechanical activity in Pb(ZrxTi1−x)O3 ceramies near the morphotropic phase boundary

Abstract: On the basis of the planar coupling factor it is shown that the maximum in the electromechanical activity at the morphotorpic phase boundary of Pb(ZrxTi1−x)O3 solid solutions is caused by a maximum of the dielectric constant. Starting from an expansion of the free energy similar to that introduced by Devonshire and postulating a certain equivalence of the two variables of state, temperature and chemical composition, with respect to the structural and ferroelectric properties of this system, a qalitative explanation is given for the observed maximum of the dielectric constant at the phase boundary. Am Beispiel des planaren Kopplungsfaktors wird gezeigt, das das Maximum der piezoelektrischen Aktivitat an der morphotropen Phasengrenze des Systems Pb(ZrxTi1−x)O3 von einem Maximum der Dielektrizitatskonstanten verursacht wird. Ausgehend von einer Entwicklung der freien Energie nach Devonshire und unter Postulierung einer gewissen Aquivalenz der beiden Zustandsvariablen Temperature und chemische Zusammensetzung bezuglich der strukturellen und ferroelektrischen Eigenschaften dieses Systems, wird eine qualitative Deutung des beobachteten Maximums der Dielektrizitatskonstante an der Phasengrenze gegeben.

The samarium-iron system

Abstract: The Sm-Fe system has been investigated by X-ray diffraction, thermoanalysis and metallography. Three compounds have been observed: SmFe 2 (MgCu 2 -type), SmFe 3 (PuNi 3 -type) and Sm 2 Fe 17 (Th 2 Zn 17 -type). Their lattice constants and Curie temperature have been determined. A tentative phase diagram has been constructed.

Analgesie nephropathy‐A review of the literature, 1967–1970

Abstract: The eoneept of \"analgesie nephropathy\" was first introduced in the early 1950's by Spühler and Zollinger'\"82 in Switzerland and later taken up by workers in Sweden, e.g., Crimlund,\" Bengtsson and Hood,\" Angervall and associates,' and in Australia, e.g. Kincaid-Smith,\" Burry,\" and many others. Clinieally, patients present with a his tory of headaehe, weakness, and malaise and are found to have a refractory normoehromic mieroeytie anemia, impaired renal function, and sometimes peptie ulceration. There is frequently a sterile pyuria, there may be characteristie radiologie signs, and the pathologie ehanges in the kidney are now well reeognized. This clinieal and pathologie condition was originally thought to be eaused by long-term ingestion of phenaeetin, henee the early term \"phenacetin kidney.\" Crities of the eoneept have argued that infeetion may playapart and may preeede nonspeeifie renal damage by a variety of substanees. Animal studies have not been eonclusive and have not been eonsistently reprodueible. There is now some evidenee, both elinieal and experimental, that mixtures of analgesies may be implieated. This paper reviews the literature on the subjeet whieh has appeared sinee Shelley'\" published his very comprehensive review in 1967. During the past three years there have been a large number of papers of clinieal and experimental relevanee to the eontinuing controversy. In partieular, the lesion of renal papillary neerosis in animals and man has been more clearly defined, additional clinieal eases have been deseribed, and fresh hypotheses relating to the pathogenesis of the eondition have been proposed. Shelley, in his review, emphasized that a number of questions remained unanswered. Clearly there has been, at least in some eountries, an inerease in the diagnosis of renal papillary neerosis, not assoeiated with diabetes mellitus or with obstruetion of the urinary tract, This diagnosis is made most eommonly in middleaged and elderly women, is frequently associated with the long-term abuse of analgesies, and is aeeompanied by a eharaeteristie clinieal picture. One question whieh remained unanswered in 1967 was whether the kidney lesion was eaused by the abuse of analgesies or by infeetion, allergy, or some other agent. If analgesie abuse was the eause, was phenacetin the agent or were other drugs ineriminated? How eould geographie differenees in the incidenee of renal papillary necrosis be explained, in partieular the high ineidence found in Australia and eertain parts of Sweden, compared with the low incidence in the United States and United Kingdom?

Extrusion of glass

Abstract: Extrusion is especially suitable for glasses to which the usual technologies of casting, blowing or drawing are difficult or impossible to apply. This holds for glasses with a narrow working range (short glasses), for glasses which strongly tend to crystallize and for glasses with a very high softening point. Due to the extrusion pressure, the working range is enlarged to higher viscosities, the manufacturing process is shifted into a range of lower cyrstallization rates and moreover the lower working temperature can be controlled in a more convenient way. Furthermore, extrusion could be applied to conventional glasses, if products with other than circular cross sections are to be manufactured. For the process frit can be used. Quantitative measurements showed that the flow behaviour of the glass is in satisfactory agreement with the results obtained from the Hagen-Poiseuille law.

Device for the transmission of synchronous pulse signals

Abstract: A receiver for a synchronous pulse signal formed with the clock, carrier, and shift frequencies having mutual ratios of integers. The receiver has two channels controlled by a clock pulse generator synchronized to a received signal and followed by a pulse regenerator. The receiver is well suited for an embodiment using integrated circuits.

Method of manufacturing a gas discharge panel and panel manufactured by said method

Abstract: A gas discharge panel of which one or both panel plates are provided with cavities in the bottoms of which a conductor extends, which cavities and conductors are pressed in the softened material of the panel plate by means of a pressure plate in which cores in the form of balls or rods are secured, which cores comprise in the free end a groove in which the conductors are provided, which conductors remain behind in the panel plate after impression.

The In‐Ga‐Sb Ternary Phase Diagram

Abstract: The ternary phase diagram for In‐Ga‐Sb has been determined experimentally and has been verified by calculation. Liquidus compositions are measured along several isotherms together with several solidus compositions on the pseudobinary phase diagram. For the calculation both liquid and solid are assumed to be nonideal. The activity coefficients are calculated using a model with temperature dependent interaction parameters.

Monitoring and shutdown apparatus

Abstract: A shutdown and/or alarm system is actuated by a monitor. The system includes an AND circuit which comprises a switch and two multivibrators. The multivibrators have different reset times. A signal from the monitor closes the switch for a given time interval, and triggers and initiates resetting of the multivibrators at the end of this interval. Signals from the multivibrators are passed through the switch to energize a shutdown device and/or an alarm.

Method of decorating a glazed article utilizing a beam of corpuscular energy

Abstract: The surface of an article, such as a glass envelope for an electric lamp, is provided with a decorative pattern or indicia by coating the article with a vitreous material that includes a substance (such as lead oxide) that undergoes a permanent change in color when heated under reducing conditions, subjecting the article to a laser beam and a reducing gas flame, and varying the position of the article relative to the beam at a speed and in a manner such that the beam scans the article and thereby melts preselected portions of the vitreous coating and changes the color of such portions. In the case of a vitreous or ceramic article that is susceptible to thermally-induced fracturing, the vitreous coating material is preferably deposited on the article in the form of a frit and the article is preheated to a temperature which is near or above its strain point, thus fusing the frit in place just before the glazed heated article is exposed to the reducing environment and laser beam.

Measurement and computer-aided optimization of spectral power distributions

Abstract: This paper describes a rapid and reliable method of measuring the spectral power distribution of a lamp. The computer program which calculates the colour rendering index and the correlated colour temperature from this s.p,d, is used to study the influence on colour rendering and correlated colour temperature of adding a line to the spectrum of a metal halide (HPI) lamp. Another application of the computer program shows that with spectra consisting of only three spectral lines it is possible to achieve a general colour rendering index Ra~80. It appears that the three lines have to be chosen in three different wavelength regions, namely a blue line in the region 455-485 nm, a green line in the region 525-560 nm and a red line in the region 595-620 nm. With decreasing colour temperature the optimal wavelengths shift slightly to longer wavelengths whilst the general colour rendering index slightly increases.

Method of making semiconductor devices with selective doping and selective oxidation

Abstract: A method of manufacturing a semiconductor device having an inset oxide pattern obtained by local oxidation, which pattern is bounded only partly by a doped surface zone. According to the invention a first mask is provided on the semiconductor surface after which etching is carried out so that a freely projecting edge of said mask is formed by underetching. During the local doping of the etched surface the masking provided by said edge is used directly or indirectly after which the oxide pattern is provided.

KONDO SIDEBANDS IN CeAl$sub 3$ AND RELATED PSEUDOBINARY COMPOUNDS.

Abstract: The temperature dependence of the electrical resistivity (1.3-300 \ifmmode^\circ\else\textdegree\fi{}K) has been studied for the isomorphous compounds ${\mathrm{Ce}}_{1\ensuremath{-}x}{\mathrm{La}}_{x}{\mathrm{Al}}_{3}$, ${\mathrm{Ce}}_{1\ensuremath{-}x}{\mathrm{Y}}_{x}{\mathrm{Al}}_{3}$, and ${\mathrm{Ce}}_{1\ensuremath{-}x}{\mathrm{Th}}_{x}{\mathrm{Al}}_{3}$. In these compounds, one or two maxima have been observed in the $\ensuremath{\rho}\ensuremath{-}\mathrm{v}\mathrm{s}\ensuremath{-}T$ curve. An analysis of the experimental results is presented in terms of the Kondo sideband theory, which describes Kondo exchange scattering of the conduction electrons in the presence of localized moments whose ground-state manifold is split owing to the presence of crystalline fields. It is shown that the changes observed in $\ensuremath{\rho}$ behavior for Ce${\mathrm{Al}}_{3}$ upon replacement of Ce by La, Y, or Th can be correlated with changes in the crystal field parameters, and in the case of Th also with changes in the density of states of the conduction electrons.