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Parts, Hybrids, and Packaging, IEEE Transactions on

Issue 4 • Date December 1972

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Displaying Results 1 - 10 of 10
  • Who's Who in G-PHP

    Page(s): 2
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    Freely Available from IEEE
  • Guest Editorial: The Tutorial Paper as a Design Tool

    Page(s): 3
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    Freely Available from IEEE
  • Some Effects of Temperature on Material Properties and Device Reliability

    Page(s): 4 - 14
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    The purpose of this paper is to give the nonspecialist some tools he can use to gain insight into some of the complex thermal problems encountered in electronic assemblies. Some causes of thermal problems in electronic components and assemblies are briefly reviewed on a fundamental level. This review includes a discussion of some basic thermal parameters, the effect of the thermal environment on other physical parameters, and ways the thermal environment affects the operating characteristics and life of electronic assemblies. Most of the paper is devoted to specific thermal design and cooling problems. Techniques are presented which can be used to determine the thermal stresses that develop in some assemblies during soldering, shipping, and storage; and to determine the cyclic thermal stresses that develop during normal operation. In addition, some fundamentals of heat transfer from minute electronic components by conduction, convection, and radiation are reviewed, and techniques are described that can be used to predict the heat transfer from both single and multiple sources. Experimental and analytical studies are cited to illustrate each topic discussed. For example, experimental data are presented to show the effect temperature has on the coefficient of thermal expansion and the compliance of epoxy-glass composites and its effect on stress relaxation in solder, These data are then used to analyze the form of the stresses that exist in a plated-through hole during soldering and temperature cycling. View full abstract»

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  • Electrooptic Liquid Crystal Devices: Principles and Applications

    Page(s): 24 - 37
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    The principles governing the operation and performance of devices utilizing mesomorphic anisotropic fluids (liquid crystals) am reviewed and systematized according to materials, dielectric type, and mode of operation. A further breakdown is made into whether the phenomenon is a change in optical density (color), diffraction, or scattering. Some of the possible directions for optical applications are indicated for which liquid crystals may be unique. Performance, life, circuit parameters, and drive characteristics are considered. View full abstract»

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  • Glass-Sealed Leads on Electric Components

    Page(s): 45 - 48
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    Industry specialists do most of the fabrication of glass-sealed headers for suppliers of hermetic electronic components. Too often, these specialists are not acquainted with the effect that header processing can have on component fabrication, assembly or use. Almost as frequently, the component maker is unable to relate his own processing difficulties to problems introduced during the previous handling of subassemblies. This paper presents an analysis of the effect that the oxidation of leads prior to glass sealing has on component assembly and use. Metallographic techniques are useful for the control of affected component parts. Some examples of the use of metallography for the evaluation of glass-metal seals are shown. View full abstract»

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  • Influence of the Protective Gas Pressure on Showering in Dry Reed Contacts

    Page(s): 58 - 61
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    We investigated the effect of a reduction of the protective gas pressure at fixed static breakdown Voltage on the appearance of showering (intermittent arcing) in dry reed contacts that break inductive circuits by using a discharge gap arid an auxiliary interruptor to simulate this condition. We found a critical pressure range, where showering, capable of causing strong erosion, is replaced by glow discharges. In the case of actually operating contacts, it was only possible to reduce showering for forty percent of the total openings by lowering the gas pressure. These results can be explained by suggesting that in the case of the discharge gap that represents a relay opening contact having large contact spacing, the showering arcs, developed from the preceding glow discharges, can be minimized by reducing the gas pressure in such a way that arc formation is inhibited. In the case of the operating contact, other mechanisms exist, such as high electrical fields and high temperature spots. These mechanisms are not affected much by reducing the gas pressure; thus showering is only partially prevented. View full abstract»

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  • The Relation of Ceramics Processing to Materials Properties for Electronic Applications

    Page(s): 15 - 23
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    General properties of electronic ceramics are examined, noting especially their influence upon fabrication economics and quality. Particular emphasis is placed upon the preparation of sinterable powders to attain high densification. The effects of fabrication technique and powder preparation upon ceramic quality and dimensional control are pointed out. Recent developments and possible future trends in electronic ceramic materials are discussed briefly. View full abstract»

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  • Miniaturization of Delay Lines Through the Use of the Dielectric and Structural Properties of Plastics

    Page(s): 51 - 57
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    A miniaturized delay line wound on a sectionalized plastic spool is described. The surfaces of the spool and flange separators are coated with a silver paint which serves as a capacitor electrode. The other capacitor electrode is a winding conductor and the capacitance is derived from the wire insulation. To raise the capacitance the spaces between turns of the windings and between the windings and the flange or-core are filled with an oil having a dielectric constant somewhat greeter than air. The surface electrical resistance of a silver paint electrode has a significant effect on the output voltage loss and the capacitance of the delay line. In general, the thinner silver paint electrodes result in less output voltage loss and also lower capacitance. In view of the output voltage and the delay time of this delay line, suitable surface electrical resistance is 15 to 25/Omeg/square, hence the effect of thickness of silver paint electrodes is discussed. The temperature coefficient of delay time is improved by using a filler oil with a negative temperature coefficient of dielectric constant. A further improvement is achieved by a newly developed packing method. The miniaturized delay line in a size of 11x14x45mm has a low output loss of 3 dB at 4 MHz. View full abstract»

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  • Antennas System Cables and Guys Combining High Strength and Optimum Dielectric Characteristics

    Page(s): 38 - 44
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    A comparison has been made of high strength filament materials having low dielectric and loss-tangent properties for use in antennae cables; lines and guys. The availability of type S glass fibers of higher strength than type E and the more recent production of high-modulus carbon filaments, and high-modulus organic type polymeric fibers offer several materials to choose from for optimum design. Since frequently both the mechanical and electrical properties are important for cables, a brief review is given of properties considered for final design and production. A specific problem and solution is analyzed with supporting data. At the Cornell University National Astronomy and Ionosphere Center in Puerto Rico, cables used in the antennas ,system had to meet the following unique combination of requirements: 1) high modulus for a low total elongation, 2) assurance of rigidity at comparatively low prestrain loads, and 3) low loss-tangent and dielectric properties. The final lines involved use of a recently developed PRD-49 organic fiber exhibiting higher polymer strength and modulus than previously obtainable. A modulus of 16.5x106psi was obtained for a line capable of supporting a 19, 000 Ib load and weighing approximately 0.04 Ib/ft of length. The implications of this work in other antennae and related design problems are also discussed. View full abstract»

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  • Electrical Contacts to Ion Cleaned N-Type Gallium Arsenide

    Page(s): 49 - 50
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    The electrical current through silver contacts evaporated onto n-type gallium arsenide as a function of surface treatment is reported. Contacts to untreated gallium arsenide exhibit the expected high resistance. Surface cleaning by argon ion bombardment reduces the resistance by three orders of magnitude. The electrical resistance beyond 850 eV increases rapidly with ion bombardment energy. The resistance minimum at 850 eV is explained semiquantitatively in terms of a balance between cleaning and surface damage. This type of contact is appropriate for addition to a finished material whose properties are to be investigated, but may not be adequately ohmic for use on production devices. View full abstract»

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Aims & Scope

This Transaction ceased production in 1977. The current publication is titled IEEE Transactions on Components, Packaging, and Manufacturing Technology.

Full Aims & Scope