Showing papers by "Philips published in 1980"

Cohesion in alloys - fundamentals of a semi-empirical model

Abstract: A semi-empirical model of alloy cohesion involving two material constants for each element is introduced by means of the physical ideas underlying the scheme The resulting expressions for the heat of formation of binary alloys are presented and their applicability in various extreme situations is discussed The model is shown to reproduce a vast amount of experimental information on the sign of heats of formation Detailed comparison with experiment for particular classes of alloys will be presented in the sequels to this paper

The Hall effect in polycrystalline and powdered semiconductors

Abstract: Gives a critical review of idealised two-phase geometrical models. These treatments derive expressions for the resistivity and Hall coefficient of a composite material in terms of the properties of its constituents. The authors show that these models can be applied to the interpretation of transport measurements in polycrystalline films and powder layers. Important distinctions are made depending on whether the depletion layers extend completely or partially through the grains, whether the Debye length is greater or less than the grain size and whether the mean free path is greater or less than the grain size. The authors discuss the theoretical treatment of the Hall effect in percolative systems, as geometrical models neglect percolation. The modulation of Hall coefficient and conductivity by illumination and the adsorption and desorption of ambient gases are also considered.

Cross-section and rate formulas for electron-impact ionization, excitation, deexcitation, and total depopulation of excited atoms

Abstract: For electron-induced ionization, excitation, and de-excitation, mainly from excited atomic states, a detailed analysis is presented of the dependence of the cross sections and rate coefficients on electron energy and temperature, and on atomic parameters. A wide energy range is covered, including sudden as well as adiabatic collisions. By combining the available experimental and theoretical information, a set of simple analytical formulas is constructed for the cross sections and rate coefficients of the processes mentioned, for the total depopulation, and for three-body recombination. The formulas account for large deviations from classical and semiclassical scaling, as found for excitation. They agree with experimental data and with the theories in their respective ranges of validity, but have a wider range of validity than the separate theories. The simple analytical form further facilitates the application in plasma modeling.

The behaviour of flip-flops used as synchronizers and prediction of their failure rate

Abstract: Deals with the behavior of flip-flops, used as input synchronizers, in particular when they operate in the metastable region. It is shown first, theoretically as well as experimentally, that the average rate of system failures, due to the occurrence of metastable states (MSSs), is independent of circuit noise. A formula which describes the probability of occurrence of a metastable state has been derived. To verify the theory, measurements have been made on a flip-flop made in n-channel MOS technology. Also a method is given for predicting the average number of system failures, for a given flip-flop, occurring over a year. This method is applied to predict this average failure rate for the designed synchronizer.

Lateral double-diffused MOS transistor device

Abstract: A lateral double-diffused MOS transistor includes a field-shaping semiconductor layer which serves to improve the breakdown voltage and/or on-resistance characteristics of the device. The field-shaping layer redistributes the electrical field in the device during operation in order to eliminate electrical field crowding in portions of the device where breakdown would otherwise first occur. The field shaping layer may be a buried layer, a surface layer, or a composite layer having both buried and surface layer portions.

The action of tin compounds in condensation‐type RTV silicone rubbers

Abstract: The vulcanization of RTV (=room temperature vulcanizing) silicone rubbers under the action of organotin compounds is investigated. The mechanism for the cure is inferred from the chemical properties of a variety of relevant organotin compounds and is illustrated with the reactions that occur when dialkyltin dicarboxylates (A) are used as catalysts. The resulting organotin hydroxide (B) is shown to be the actual catalyst. With tetraethoxysilane (2) it forms organotin silanolates (D). Silanolysis of this compound results in the formation of a new siloxane linkage and recovery of the actual catalyst. Alkoxysilanes in which part of the alkoxy groups is replaced by siloxy groups, appear to be more reactive than the initial alkoxysilanes. At elevated temperatures side-reactions like condensation of silanols with alcohols under the action of organotin compounds become increasingly prominent. Heating during cure effects, that part of the silanols becomes blocked by alkoxy groups. The mechanical properties of the resulting rubbers are usually far from optimum. During heating of cured rubber in a confined atmosphere, i.e., in the presence of the alcohol formed during cure, condensation of silanols with alcohol occurs too. Because these are equilibrium reactions, this process finally leads to complete degradation of the rubber.

The origin of magnetic birefringence and dichroism in magnetic fluids

Abstract: The optical birefringence and dichroism observed in magnetic fluids when subjected to a magnetic field are generally ascribed to orientation of the particles, to anisotropic spatial ordering, or to string formation. Magnitude, concentration- and time dependence of the anisotropies predicted by these mechanisms are compared with the available experimental data. This leads to the conclusion that orientation of small aggregates and secondary aggregation of large aggregates into strings are the most likely cause of the large anisotropies. Orientation of single particles can be responsible for small anisotropies only. Field-induced spatial ordering has, at least optically, not (yet) been observed.

Electric incandescent lamp

Abstract: The electric incandescent lamp has a sintered glass plate (1) through which current conductors (2) and a metal tube (3) extend. An incandescent body (4) is connected to said current conductors (2) aligned with respect to the sintered plate (1). A glass bulb (5) is present over the incandescent body (4), gastight secured to the sintered plate (1) by means of enamel (6). A water getter (20) and a heavy gas at an elevated pressure are present inside the glass bulb (5). The lamp may consume a relatively high power and may be relatively small, but nevertheless has a relatively long life.

Quantitative secondary ion mass spectrometry: A review

Abstract: Quantitative analysis in general aims at determining the value of a selected physical or chemical property of a given sample. With SIMS, in particular, the parameters to be determined are the concentration of a given element and also its distribution, both in depth and along the surface. Every measurement is affected by a given overall uncertainty due to statistical fluctuations in the measured signal and to systematic errors related to the experimental conditions. A discussion is devoted to the experimental conditions which influence the reproducibility of the measured signal and give rise to systematic errors, e.g. charging effects, matrix effects, selective sputtering and mass-dependent transmission, etc. The various methods used to derive the desired elemental concentration and its distribution in the sample from the raw measured data are evaluated, namely the use of calibration curves, relative sensitivity factors, fitting parameter methods and first-principle methods. Finally, the question is considered of how representative is the value determined from the (usually small) volume with respect to the composition of the bulk of the sample (sampling error).

Dynamic properties of magnetic domain walls and magnetic bubbles

Abstract: The present state of understanding of the dynamics of magnetic domain walls and magnetic bubbles is reviewed The theory of domain wall motion for the linear and non-linear regions is outlined Experimental techniques for straight walls and magnetic bubbles are discussed An extensive comparison between theory and experiment is made Topics included are peak and saturation velocities, mobility, inertial effects and overshoot, hard bubbles, wall states and state transformations in magnetic bubbles Origins of wall damping are also discussed

On the heats of formation of the binary hydrides of transition metals

Abstract: It is demonstrated that the available experimental information on the heats of formation of binary transition metal hydrides can be interpreted in terms of an empirical model in which energy effects are treated as contact interactions between metal atom cells and hydrogen atom cells. From the model it is apparent that, for the various binary metalhydrogen systems in which stable hydrides occur, the maximum concentration of hydrogen corresponds to approximately the same volume concentration of hydrogen. Formation enthalpies of binary hydrides of all transition metals, which are required in empirical predictions of ΔH for ternary hydrides, are tabulated. A connection is made with recent band structure theoretical calculations on hydrides.

Gyrator video filter IC with automatic tuning

Abstract: A single-chip gyrator filter for separating the components of the video signal in a TV receiver is described which is suitable for mass production in a standard bipolar process (f/SUB T//spl ap/400 MHz). The 11 mm/SUP 2/ filter chip operates at frequencies up to 10 MHz, requires no tuning or alignment and has Q-factors which are stable with temperature. The IC contains an automatic tuning system which tunes the five resonators of the filter by aligning an auxiliary gyrator resonator with the crystal oscillator present in the color decoder of a TV receiver. Problems of matching the frequencies of the individual gyrator resonators are discussed, showing how alignment accuracy of 0.5 percent can be obtained when resistivities and specific capacitances have production spreads of at least 10 percent. Various gyrator circuit configurations are given which minimize the circuit complexity and, hence, the chip area. Computer aided design techniques for the filter using geometrically scaled models and macromodeling are presented and it is shown how a complete simulation of the chip led to a significant improvement in bandstop performance. Finally, the measured responses are presented and the filter performance is discussed in the light of present-day requirements.

Hydrogen sorption characteristics of Ce-3d and Y-3d intermetallic compounds

Abstract: A study of the hydrogen sorption behaviour of several intermetallic compounds based on 3d metals (M) and cerium or yttrium (R) is reported. As well as pressure-composition isotherms, an X-ray diffraction study was made of the structural changes that accompany hydrogen absorption. It was found that, in compounds of the types R 2 M 7 and RM 3 , the structure type is preserved during hydrogen absorption. In yttrium compounds expansion occurs in the c direction as well as in the basal plane of the hexagonal or rhombohedral unit cells. In cerium compounds the expansion affects the c direction exclusively. This expansion is particularly large in CeCo 3 H 4 where, with respect to CeCo 3 , the c axis increases by more than 30%.

Method, apparatus and record carrier body for optically writing information

Abstract: Disclosed is a method and apparatus for recording information on a disc-shaped record carrier body with a single beam of radiation The record carrier body is provided with a servo track which preferably exhibits a phase structure and which contains a multitude of sector addresses each associated with a portion provided with a radiation sensitive layer Before the information is recorded, the beam is switched to a low, read level and the desired address is located Simultaneously, the radial position and tangential speed of the radiation spot and the focusing of the radiation beam are checked Once the desired address is located, the beam is switched to a higher, write intensity and the information is recorded on the radiation sensitive layer of the portion associated with that address During recording, the radiation returning from the record carrier can be used to check whether the information is recorded correctly During reading of the recorded information, the servo track may be used for positioning the radiation spot on the information track

The All‐Time Requirement of Spare Parts for Service After Sales—Theoretical Analysis and Practical Results

Abstract: An industry which manufactures and sells products that are liable to failure (e.g. TV sets, tape recorders, washing machines or refrigerators), usually has a department for “service after sales”. Such a department must distribute information on how to repair products, and has to supply spare parts to replace defective components during a given number of years. We call these parts service parts. Three phases can be distinguished in the life‐cycle of service parts:

Chapter 4 Rare earth compounds

Abstract: Publisher Summary This chapter discusses rare earth compounds. The number of stable binary intermetallic compounds in which one of the components is a rare earth element is of the order of a thousand. Combination with elements of much smaller metallic radii then encompasses a much larger number of possible atomic arrangements of sufficiently high space filling than would be the case for two components of almost equal size. A meaningful study of the physical properties of intermetallic compounds can only be made on single phase materials. Only a fraction of the compounds is in single phase condition after the melting together of the components. The chapter explains the compounds with non-magnetic elements and compounds with d-transition metals. It also explains ternary compounds or hydrides.

Five Popular Probability Density Functions: A Comparison in the Field of Stock-Control Models

Abstract: For the statistical description of a demand process, many probability density functions (pdf) are available, each having its advantages and drawbacks. How do they compare when in application? Is it true that the shape of the pdf is not relevant? This paper deals with one application, namely a simple s,Q stock control system. Assuming for the lead time demand successively five different pdf's (Gaussian, logistic, gamma, log-normal, Weibull) and using the service level as a criterion, it is shown that for this application (1) the numerical differences between the selected functions are in fact negligible; (2) the logistic pdf produces a formula that only contains elementary transcendental functions; (3) the other pdf's lead to much more complex expressions.