Showing papers by "University of Colorado Colorado Springs published in 1983"

Transverse elastic waves in periodically layered infinite and semi-infinite media

Abstract: The propagation of transverse elastic waves both perpendicular and parallel to the laminations of infinite and semi-infinite periodically layered media is studied. The displacement fields and the dispersion relations for such waves are obtained analytically, and the latter are solved numerically to yield the corresponding dispersion curves. It is shown that a semi-infinite medium layered periodically parallel to its stress-free surface can support shear horizontal surface acoustic waves that have no counterpart in a homogeneous medium. Finally, the dynamical elastic Green's function for a semi-infinite medium layered periodically parallel to its stress-free surface is obtained, and its possible application to Brillouin scattering studies of the surface acoustic waves on such a medium is discussed.

Magnetic excitations in layered media: Spin waves and the light-scattering spectrum

Abstract: We present an analysis of the spin-wave spectrum of a semi-infinite stack of ferromagnetic films, each of which is separated by a gap filled by a nonmagnetic medium. This is done within a formalism which includes the Zeeman and dipolar contributions to the spin-wave energy, with exchange omitted. We then calculate the spin-wave contribution to the Brillouin spectrum of such a system, in the backscattering geometry. The aim is to compare the spectrum for scattering from a sample with this geometry, with that from an isolated film. Two features unique to the stack appear in the spectrum. Each film, in isolation, possesses surface spin waves on its boundaries (Damon-Eshbach waves). In the layered geometry these interact to form a band of excitations of the array, which has nonvanishing component of wave vector normal to the stack. We find a feature in the spectrum associated with scattering from this band of modes; the position of the peak is controlled by dispersion introduced by interfilm interactions. Under certain conditions, the semi-infinite stack possesses a surface spin wave, whose eigenfunction is a linear superposition of individual film states, with amplitude that decays to zero as one moves down into the stack interior. This mode also produces a distinct feature in the light-scattering spectrum. These points are illustrated with a series of calculations of the spectrum, for parameters characteristic of layered ultrathin coherent structures.

Leaving Competitive Sport: Retirement or Rebirth?

Abstract: This paper reviews existing information on retirement from sport and offers an interpretation of the retirement process that will both challenge widespread assumptions held by sport sociologists and provide hypotheses for future research. The dynamics of the retirement process are discussed for athletes in top-level interscholastic and amateur sports as well as in professional sports. Existing data suggest that retirement for athletes in each of these contexts is not an inevitable source of stress, identity crises, or adjustment problems. It is argued that the dynamics of the sport retirement process are grounded in the social structural context in which retirement takes place. Factors such as gender, race, age, socioeconomic status, and social and emotional support networks shape the manner in which one makes the transition out of sport. Therefore, retirement from sport sometimes may be the scene of stress and trauma but, by itself, it often is not the major cause of those problems.

Method and apparatus for orally dispensing liquid medication

Abstract: A container housing liquid medication is provided together with a syringe and a coupling member for use in orally administering the medication to a patient. The coupling member is fastened to the container and includes a head member projecting upwardly to receive an inner tip of the syringe barrel. The liquid medication is dispensed from the container into a barrel of the syringe through a bore of the head member when a plunger is moved within the syringe barrel. After a predetermined amount of medication is received by the syringe barrel, the syringe barrel is removed from the head member and the predetermined amount of medication is administered orally to the patient. A cap member attached to the coupling member by means of a strap closes off the bore so that no medication escapes from the container when the syringe is disconnected from the head member. In one particular embodiment, a valve means is connected to the coupling member to permit selective communication between the container and the syringe barrel.

The effect of mood and incentives on helping: Are there some things money can't buy?

Abstract: Happy, guilty, and neutral mood states were induced in participants who were then provided with an opportunity to donate blood for free, to donate in exchange for $5, or to choose between donating for free or for $5. As expected, there was a significantly higher incidence of helping when subjects felt happy and guilty as opposed to emotively neutral. Contrary to predictions, helping was unaffected by the type of incentive (donate for $5, donate for free, choose $5/free) subjects were offered in interaction with their mood state. However, the type of incentive did seem to influence the postdonation emotions of subjects: Guilty subjects who donated for money felt significantly less guilty following donation than prior to it and happy subjects felt more self-altruistic (kind and generous) following donation when they helped for free. The results are discussed in terms of Cialdini's negative state relief model (for negative moods) and the intrinsic qualities of helping (for positive moods).

Conductive elastomeric ink composition

Abstract: A conductive elastomeric ink is described comprised of very fine nickel particles admixed in a silicone binder. The ink has utility in elastomeric switch control devices, printed circuits and the like.

Snap-Back: A Stable Regenerative Breakdown Mode of MOS Devices

Abstract: N-channel MOS transistors used in nMOS and in CMOS microelectronic circuits have a drain-to-source breakdown characteristic showing a negative resistance region. Activating this mode of operation leads to a drop in source-to-drain voltage and to a large drain current. Snap-back is not a four-layer (SCR, latch-up) phenomenon, but, like latch-up, can be initiated by current injection into the p-well, by avalanching junctions or by exposure to ionizing radiation. The sustaining voltage can be significantly below the drain-substrate avalanche voltage thereby limiting the maximum operating voltage. In this paper we present a qualitative model for snapback--local conductivity modulation occurring in the intrinsic base region of the parasitic bipolar transistor leading to regenerative feedback. Effects of process variations on the snap-back characteristics are presented as are triggering sensitivities to ionizing radiation.

An estimation of u.s. family wealth and its distribution from microdata, 1973

Abstract: This paper presents a method of estimating U.S. family net wealth across the entire population, utilizing capitalization of several income items available from income tax microdata. Other forms of wealth, and debt, are indirectly estimated using relationships gleaned from estate tax data. Concentration in the distribution of wealth, and assets such as corporate stock, are measured with Gini coefficients and Lorenz curve analysis and compared to similar estimates of concentration in the distribution of income. Comparisons of the results with previous estimates for the United States are made in the latter section of the paper.

CMOS substrate bias generator having only P channel transistors in the charge pump

Abstract: A CMOS substrate bias generator including a PMOS charge pump and a regulator for controlling the operation of the substrate bias generator. The substrate bias generator further includes an input circuit, a reference circuit to provide a reference voltage, a comparison circuit to compare voltage levels between the input and the reference circuit, and output circuitry to provide a signal from the comparison circuitry to the substrate bias generator. The comparison circuitry further includes hysteresis circuitry tending to preserve voltage at a node in the comparison circuit despite an imbalance between the input circuit and the reference circuit.

Minimum-shift keyed modem implementations for high data rates

Abstract: IGITAL communications links capable of conveying data at hundreds of megabits per second (Mb/s) are becoming increasingly important in various applications. An example is the use of time division multiple access (TDMA) transmission through a satellite relay wherein several data channels are routed through single uplink and downlink paths (antenna beams). Separation of the channels from each other is accomplished through interleaving and deinterleaving in time, with possible rerouting taking place in the satellite. When carrying traffic from large metropolitan areas, the required data rates can exceed 100 Mb/s. One such implementation, currently under study by NASA,' involves data transmission at rates of up to 550 Mb/s. Such applications require the use of modulation schemes that use the available bandwidth efficiently. Furthermore, because power is at a premium on board a satellite, the utmost in power efficiency is desired of the chosen modulation scheme. This implies the use of a constant-envelope modulation scheme since amplifiers, such as traveling wavetube amplifiers, are most efficient when operated near saturation. Three popular constant-envelope modulation schemes for efficient transmission of digital data are quadriphase-shift keying (QPSK), offset (or staggered) quadriphase-shift keying (OQPSK), and minimum-shift keying (MSK). Two excellent recent articles [1,2] in IEEE Communications Magazine have discussed their general properties and attributes as well as those of other modulation schemes with constant (or nearly constant) envelopes. Other recent papers [3-61 have presented analytical results and computer

An Analysis of Air Force EOQ Data with an Application to Reorder Point Calculation

Abstract: One of the important uses of an EOQ item's distribution of lead time demand is to set its reorder point. This paper shows that a realistic model of observed demand patterns can be chosen from the compound Poisson family of distributions. Actual historical data from several U.S. Air Force bases are analyzed using the geometric-Poisson and constant-Poisson distributions. The control discipline is order quantity, reorder point with continuous review. The service level is based on percent of demand supplied during lead time and is consistent with current USAF methodology. The reorder point is based on independent calculations and no attempt is made to jointly optimize the order quantity and reorder point. Lead time is assumed to be known and constant.

Phonon focusing at surfaces

Abstract: Through stationary-phase asymptotic analysis of the elastic Green's function for a semi-infinite anisotropic elastic solid, we calculate the focusing of surface phonons. We present results for surface-phonon focusing on the (100), (110), and (111) surfaces of NaCl, Ge, and Cu. In addition we present results showing that pseudosurface waves will also be focused.

Dock seal with adjustable top seal

Abstract: A loading dock seal with an adjustable top seal for providing a weather-tight seal between a loading access opening of a loading dock and vehicles of various heights which includes a compressible pad means surrounding at least the vertical sides of the opening and made of a durable yet resilient material to provide a weather-tight seal on opposite vertical sides between the pad and the vehicle being unloaded. A curtain means, attached at its upper edge above the loading access opening and at its lower edge to a tubular top seal, is of sufficient width to cover the opening. The top seal is vertically adjustable from a storage position above the opening to a sealing position upon the roof of the vehicle thereby combining with the curtain to provide a weather-tight seal between the building and the vehicle.

Endogenous opiates mediate radiogenic behavioral change

Abstract: Exposure of C57BL/6J mice to ionizing radiation caused stereotypical locomotor hyperactivity similar to that produced by morphine. Naloxone administration prevented this radiation-induced behavioral activation. These results support the hypothesis that endorphins are involved in some aspects of radiogenic behavioral change.

Cloning of the δ-aminolevulinic acid synthase structural gene in yeast.

Abstract: HEM1, the structural gene for δ-aminolevulinic acid synthase, has been isolated on recombinant plasmids. A yeast genomic pool constructed in the E. coli — yeast shuttle vector YEp13 was used to clone the HEM1 gene by complementation. A leu2 hem1 yeast mutants was transformed with the yeast genomic pool and hybrid YEp13 plasmids carrying the HEM1 gene were cloned by their ability to complement both the leu2 and hem1 mutations in the recipient strain. The yeast transformants, bearing the HEM1-containing plasmids pYe(HEM1), showed a 24–28 fold increase in δ-aminolevulinic acid synthase activity and in the intracellular content of δ-aminolevulinic acid (5–8 fold) as compared to wild type strains, suggesting that the p(HEM1) gene is being expressed as a catalytically active enzyme which can be transported into the mitochondria. However, the transformant strains did not present higher-than-normal content of heme or cytochromes either in glucose or in glycerol media, indicating that the production of δ-aminolevulinic acid is not the rate-limiting step in heme biosynthesis in yeast.

A 5V-only EEPROM with internal program/erase control

Abstract: An 8K×8 EEPROM, using double-poly, silicon gate, nitrox technology, will be described. A 176μm2cell size has been achieved with 3μ design rules. Internal high voltage generation and program/erase control provides 5V-only external interfacing.

Anisotropic silicide etching process

Abstract: A process for anisotropically etching semiconductor products which include a lower dielectric layer (12), an intermediate polysilicon layer (14), and an upper silicide layer (16) such as titanium silicide. A pattern-defining layer (20) will normally overlie the silicide layer to define target areas to be etched. In a first step, the silicide is etched through using Freon 115 chloro, pentafluorethane (C2ClF5) in a plasma etching chamber conditioned to provide a reactive ion etch. The etch is completed in the same chamber using a second gas which includes an amount of Cl2 selected to etch anisotropically through the polysilicon layer without substantially etching the dielectric layer. Preferably, both etches occur after covering inner surfaces of the etching chamber with a material which releases molecules of the character included in the pattern-defining layer, such as Kapton, a polyamide, in the disclosed example.

Method and apparatus of reducing latch-up susceptibility in CMOS integrated circuits

Abstract: Method and apparatus for controlling latch-up in a CMOS circuit senses a power supply transition, clamps the substrate to ground in response to sensing a power supply transition, and releases the clamp after the power supply transition A charge pump pumps the substrate illustratively to -3 volts The charge pump, clamping transistor and related elements are on the same CMOS substrate where latch-up is to be controlled The substrate to ground capacitance of the substrate is increased to prevent localized substrate voltage disturbances which may induce latch-up

Beam directing micromanipulator for laser device

Abstract: A beam deflecting assembly in a laser device for precision manual control of the point of impact of a laser beam on a selected target site. The assembly includes a pivotable joy-stick universally coupled to an angled manipulator arm which in turn is pivotably connected to a mirror mount in which a beam deflecting mirror is mounted. The mount is rotatable about a vertical axis and includes a yoke for pivoting the mirror about a horizontal axis. Deflection of the joy-stick in the horizontal direction results in rotation of the mount and, independently, deflection in the vertical axis results in pivoting the mirror mount about the horizontal axis. The components of the assembly are dimensioned such that a movement in the free end of the joy-stick is reflected in a corresponding displacement in angle and distance in the point of impact of the delivered laser beam on a selected target plane to give the operator of the laser device a sense of direct control of the beam.

Continuous-plus embedded data position control method for magnetic disk device

Abstract: A method for use in a magnetic disk drive of the type in which a disk assembly has a dedicated servo surface containing circular tracks of dedicated servo signals (75) and data surfaces containing circular data tracks divided into sectors each of which includes a data field (256) and a servo field (254) containing embedded servo signals, a dedicated servo signal detector for detecting servo signals (75) on said dedicated surface, an embedded signal detector for detecting embedded servo signals (254) on a data surface and a head positioning system for positioning a read/write head over a selec­ted data track. The entire output of the embedded signal detector is combined with the high-frequency components of the output of the dedicated signal detec­tor to produce a composite track error signal and the head positioning system responds to the composite track error signal to maintain the read/write head over the selected data track.

Work function measurement of tungsten polycide gate structures

Abstract: Three MOS gate structures; polysilicon, tungsten silicide and tungsten polycide, were fabricated and their workfunctions measured with the high frequency C-V technique. The work functions were 4.14 ev and 4.82 ev for phosphorus doped polysilicon and silicon-rich tungsten silicide, respectively. The tungsten polycide structure, however, showed a variance between 4.14 ev and 4.38 ev for different experiments. The polycide MOS device threshold was about 0.15 volt higher than that of polysilicon. Phosphorus out-diffusion and tungsten diffusion along polysilicon grain boundaries were postulated to explain this phenomenon.