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Manufacturing Of Atomically Sharp Silicon Tips And Their Use As Photocathodes, W. I. Karian, Larry V. Knight, David D. Allred, A. Reyes-Mena Jan 1992

Manufacturing Of Atomically Sharp Silicon Tips And Their Use As Photocathodes, W. I. Karian, Larry V. Knight, David D. Allred, A. Reyes-Mena

Faculty Publications

The discovery and understanding of the photoelectric effect led to the study of photoemissive materials fall into two major categories: classical photoemitters and negative-electron-affinity (NEA) materials. Classical photoemitters usually involve an alkali metal, a group-V element such as phosphorus, silver, and/or oxygen. An example is the Ag-O-Cs (S1) photoemitter. NEA photocathodes consist of a photoconductive single crystal semiconductor covered with a thin layer of cesium and oxygen. This layer lowers the work function of the photocathode. A dipole layer is formed at the surface, and band bending occurs. This lowers the effective work function. An example is the GaAs(CsO) photocathode …

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Glottal Airflow And Electroglottographic Measures Of Vocal Function At Multiple Intensities, Christopher Dromey, Elaine T. Stathopouloss, Christine M. Sapienza Jan 1992

Glottal Airflow And Electroglottographic Measures Of Vocal Function At Multiple Intensities, Christopher Dromey, Elaine T. Stathopouloss, Christine M. Sapienza

Faculty Publications

Summary: Ten normal female subjects produced syllables at 5 dB increments from soft to loud. The differentiated electroglottogram (dEGG) open and speed quotients were compared to similar quotients from the inverse-filtered airflow waveform. The latter were measured according to objective and subjective criteria. The data indicate that the open quotient from the airflow waveform decreased as the intensity increased. The dEGG open quotient did not demonstrate this trend. The speed quotient from airflow increased initially with vocal intensity and decreased again as the intensity ceiling was approached. The ratio of closing to opening slopes calculated from peaks in the dEGG …

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Characterization Of As-Prepared And Annealed W/C Multilayer Thin Films, David D. Allred, Qi Wang, Jesus González-Hernández, B. S. Chao, D. A. Pawlik Jan 1992

Characterization Of As-Prepared And Annealed W/C Multilayer Thin Films, David D. Allred, Qi Wang, Jesus González-Hernández, B. S. Chao, D. A. Pawlik

Faculty Publications

Tungsten/carbon (W/C) multilayer thin films were prepared by dc magnetron sputtering. All samples consisted of 30 layer pairs with a nominal d-spacing varying from 2.5 to 14 nm, the W layer thickness was kept at 2 nm in all samples. The W/C multilayers were subjected to isochronal anneals in a quartz tube furnace at the temperature range from 500 to 950 °C under a flow of high purity Ar gas. X-ray diffraction, Raman scattering, and Auger depth profile were used to characterize the structure of the as-prepared and annealed multilayer films. Both the W and C layers appear to be …

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Chemical Percolation Model For Devolatilization: Ii. Temperature And Heating Rate Effects On Product Yields, Thomas H. Fletcher, Alan R. Kerstein, Ronald J. Pugmire, David M. Grant Jan 1992

Chemical Percolation Model For Devolatilization: Ii. Temperature And Heating Rate Effects On Product Yields, Thomas H. Fletcher, Alan R. Kerstein, Ronald J. Pugmire, David M. Grant

Faculty Publications

The chemical percolation devolatilization (CPD) model describes the devolatilization behavior of rapidly heated coal based on the chemical structure of the parent coal. Percolation lattice statistics are employed to describe the generation of tar precursors of finite size based on the number of cleaved labile bonds in the infinite lattice. The chemical percolation devolatilization model described here includes treatment of vapor-liquid equilibrium and a cross-linking mechanism. The cross-linking mechanism permits reattachment of metaplast to the infinite char matrix. A generalized vapor pressure correlation for high molecular weight hydrocarbons, such as coal tar, is proposed based on data from coal liquids. …

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The Effect Of A Tilted Magnetic Field On The Equilibrium Of A Pure Electron Plasma, Grant W. Hart Nov 1991

The Effect Of A Tilted Magnetic Field On The Equilibrium Of A Pure Electron Plasma, Grant W. Hart

Faculty Publications

If the magnetic field in a pure electron plasma containment device is not aligned with the axis of the conducting walls, the electrons in the device will accumulate at the ends of the plasma where the magnetic field lines come closest to the walls and the electrons bound to the field lines can be closest to their image charges. If the plasma is also offset radially from the center (as with an l=1 diocotron mode), then more density will accumulate at one end than the other. As the plasma revolves around the center, the electrons will slosh from one end …

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Habitat Evaluation Procedure For Rocky Mountain Bighorn Sheep In The Intermountain West, Tom S. Smith, Jerran T. Flinders, David S. Winn Oct 1991

Habitat Evaluation Procedure For Rocky Mountain Bighorn Sheep In The Intermountain West, Tom S. Smith, Jerran T. Flinders, David S. Winn

Great Basin Naturalist

Several habitat evaluation procedures have been developed for bighorn sheep. However, none of these procedures specifically addresses the Rocky Mountain subspecies nor analyzes both the quantity and quality of potential bighorn habitat with regard to minimum viable population (MVP) criteria. This bighorn habitat evaluation procedure combines (1) a quantitative assessment of bighorn range to determine if there are adequate quantities of resources to support an MVP of bighorn sheep, and (2) a qualitative assessment of a range to predict the probable density of bighorns the range can support. Extensive literature review, intensive bighorn research, and a modeling tool, pattern recognition …

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Full Issue, Vol. 51 No. 3 Oct 1991

Full Issue, Vol. 51 No. 3

Great Basin Naturalist

No abstract provided.

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Effects Of Convict Cichlids On Growth And Recruitment Of White River Springfish, Dallas Tippie, James E. Deacon, Chih-Hsiang Ho Oct 1991

Effects Of Convict Cichlids On Growth And Recruitment Of White River Springfish, Dallas Tippie, James E. Deacon, Chih-Hsiang Ho

Great Basin Naturalist

Observations of changes in population density of native White River springfish (Crenichthys baileyi) in Pahranagat Valley led to the following hypothesis: introduced convict cichlids (Cichlasoma nigrofasciatum) cause reduced growth and recruitment; cover reduces the magnitude of the effect. The hypothesis was tested by establishing sympatric and allopatric groups of the two species in experimental aquaria with and without cover. Change in volume (= mass) and length of the two species over a three-month period in spring 1986 and 1987 was measured and analyzed using 2 × 2 factorial analyses. Convict cichlids caused reduced growth and eliminated …

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Byu Studies: Into The 1990s, John W. Welch Oct 1991

Byu Studies: Into The 1990s, John W. Welch

BYU Studies

No abstract provided.

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Subject Index, Byu Studies Oct 1991

Subject Index, Byu Studies

BYU Studies

No abstract provided.

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A Self-Organizing Binary Decision Tree For Incrementally Defined Rule-Based Systems, Douglas M. Campbell, Tony R. Martinez Sep 1991

A Self-Organizing Binary Decision Tree For Incrementally Defined Rule-Based Systems, Douglas M. Campbell, Tony R. Martinez

Faculty Publications

This paper presents an adaptive self-organizing concurrent system (ASOCS) model for massively parallel processing of incrementally defined rule systems in such areas as adaptive logic, robotics, logical inference, and dynamic control. An ASOCS is an adaptive network composed of many simple computing elements operating asynchronously and in parallel. This paper focuses on adaptive algorithm 3 (AA3) and details its architecture and learning algorithm. It has advantages over previous ASOCS models in simplicity, implementability, and cost. An ASOCS can operate in either a data processing mode or a learning mode. During the data processing mode, an ASOCS acts as a parallel …

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A Physical Tutorial On Hord's Review Of Iberall-Wilkinson In Modelski's Exploring Long Cycles, A. Iberall, D. Wilkinson Apr 1991

A Physical Tutorial On Hord's Review Of Iberall-Wilkinson In Modelski's Exploring Long Cycles, A. Iberall, D. Wilkinson

Comparative Civilizations Review

No abstract provided.

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Advocacy And Inquiry In The Writing Of Latter-Day Saint History, David B. Honey, Daniel C. Peterson Apr 1991

Advocacy And Inquiry In The Writing Of Latter-Day Saint History, David B. Honey, Daniel C. Peterson

BYU Studies

No abstract provided.

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Language, Conversation, Sanity And Reality, Chauncey C. Riddle Mar 1991

Language, Conversation, Sanity And Reality, Chauncey C. Riddle

Deseret Language and Linguistic Society Symposium

No abstract provided.

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The Resolution Of Lexical Ambiguity In Machine Translation, Dan W. Higinbotham Mar 1991

The Resolution Of Lexical Ambiguity In Machine Translation, Dan W. Higinbotham

Deseret Language and Linguistic Society Symposium

No abstract provided.

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Theory Of An Atomic Beam Splitter Based On Velocity-Tuned Resonances, Scott Glasgow, P. Meystre, M. Wilkens, E. M. Wright Mar 1991

Theory Of An Atomic Beam Splitter Based On Velocity-Tuned Resonances, Scott Glasgow, P. Meystre, M. Wilkens, E. M. Wright

Faculty Publications

We develop the theory of an atomic beam splitter in which a monoenergetic beam of two-level atoms is incident normally to a classical standing-wave light field. The incident atomic wave function can be split into two coherent components with transverse momenta ±(2n + 1)fzk using velocity-tuned resonances, where n is the order of the resonance. We discuss the cases of zero- and first-order resonances in detail, and show that the velocity-tuned resonances are renormalized due to a high-frequency Stark shift. Numerical results that display the effects of a finite momentum spread in the incident atomic beam are presented.

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The Analysis Of A Model For Wave Motion In A Liquid Semiconductor: Boundary Interaction And Variable Conductivity, William V. Smith Mar 1991

The Analysis Of A Model For Wave Motion In A Liquid Semiconductor: Boundary Interaction And Variable Conductivity, William V. Smith

Faculty Publications

The theory of conducting fluids in relative motion with small conductivity is studied with a model including the Maxwell displacement current. The model is linearized, and the interaction of waves with a plane boundary in three space is studied for two orientations of the external magnetic field. It is found that two families of boundary conditions preserve energy in one orientation (external field orthogonal to the boundary), while in the other (external field parallel to the boundary) only one condition exists which preserves energy. It is shown that generalized Fourier transforms exist, generated from the generalized eigenfunction expansions. Further, it …

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Monte S. Nyman And Charles D. Tate, Jr., Eds., The Book Of Mormon: Jacob Through Words Of Mormon, To Learn With Joy, Scott Woolley Jan 1991

Monte S. Nyman And Charles D. Tate, Jr., Eds., The Book Of Mormon: Jacob Through Words Of Mormon, To Learn With Joy, Scott Woolley

Review of Books on the Book of Mormon 1989–2011

Review of The Book of Mormon: Jacob through Words of Mormon, To Learn with Joy (1990), edited by Monte S. Nyman and Charles D. Tate Jr.

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From Campus To Campus: English University Life And The Renaissance Pastoral, Gary M. Bouchard Jan 1991

From Campus To Campus: English University Life And The Renaissance Pastoral, Gary M. Bouchard

Quidditas

Literary critics have relied increasingly upon what we know of the particular goings-on at the court of Queen Elizabeth to explain all things we call Elizabethan, including a vast corpus of poetry. Pastoral poetry in particular, long regarded as an allegorical embodiment of court politics, is seen now more than ever as a product of social and political power struggles. I argue instead that the pastoral poetry of Renaissance England has to do with the academic world as much as, if not more than, with the ancillary world of the court, it was born of the academy, where Edmund Spenser …

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Structure And Optical Characterization Of Znxcd1-Xte Thin Films Prepared By The Close Spaced Vapor Transport Method, David D. Allred, Jesus González-Hernández, O. Zelaya, J. G. Mendoza-Alverez, E. López-Cruz, D. A. Pawlik Jan 1991

Structure And Optical Characterization Of Znxcd1-Xte Thin Films Prepared By The Close Spaced Vapor Transport Method, David D. Allred, Jesus González-Hernández, O. Zelaya, J. G. Mendoza-Alverez, E. López-Cruz, D. A. Pawlik

Faculty Publications

Zinc cadmium telluride (ZnxCd1-xTe) solid solution films with 0≤x≤0.12 were deposited by the close spaced vapor transport method and characterized using photoluminescence, x-ray diffraction, and scanning electron microscopy. The two former techniques indicate that films with high crystalline quality can be prepared with moderate substrate temperatures and low argon pressures. Under these conditions deposition rates of up to 1000 Å/s are achieved and Zn concentration in the film is the same as that of the source. The electron micrographs show grain sizes comparable to the film thickness.

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The Transmittances Of Thin Polymer Films And Their Suitability As A Supportive Substrate For A Soft X-Ray Solar Filter, Memorie Williams, Evan Hansen, A. Reyes-Mena, David D. Allred Jan 1991

The Transmittances Of Thin Polymer Films And Their Suitability As A Supportive Substrate For A Soft X-Ray Solar Filter, Memorie Williams, Evan Hansen, A. Reyes-Mena, David D. Allred

Faculty Publications

This paper discusses soft x-ray filter designs for the Brigham Young University "Goldhelox Project". Three polymers intended for use as a supportive substrate for a soft x-ray solar filter, having a passband centered at 171 angstroms are examined. The use of polymer substrates is examined because of vibrational and mechanical stresses associated with the shuttle launch, preventing the use of a free standing filter, and because of Goldhelox's special need to locate the filter near the imaging plane. The uniform consistency of a polymer support will prevent any imaging of the filter support structure, as would occur if a traditional …

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Home Range And Activity Patterns Of Black-Tailed Jackrabbits, Graham W. Smith Oct 1990

Home Range And Activity Patterns Of Black-Tailed Jackrabbits, Graham W. Smith

Great Basin Naturalist

Home range use and activity patterns of black-tailed jackrabbits (Lepus californicus) in northern Utah were studied using telemetry. Home range sizes ranged from < 1 km2 to 3 km2 and did not differ between sexes or among seasons. Jackrabbits were inactive during daylight, became active at dusk, and remained active throughout the night. Animals often traversed their home ranges in a few hours. During the breeding season, males were more active than females. Jackrabbits were most active during well-lit nights, and high winds decreased jackrabbit activity.

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Jean-Antoine-Nicolas De Caritat, Marquis De Condorcet. Sketch For A Historical Picture Of The Progress Of The Human Mind, Lloyd S. Swenson Jr. Oct 1990

Jean-Antoine-Nicolas De Caritat, Marquis De Condorcet. Sketch For A Historical Picture Of The Progress Of The Human Mind, Lloyd S. Swenson Jr.

Comparative Civilizations Review

No abstract provided.

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Technology And Values In Traditional China And The West: I, Kenneth R. Stunkel Oct 1990

Technology And Values In Traditional China And The West: I, Kenneth R. Stunkel

Comparative Civilizations Review

No abstract provided.

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Current Developments In Chinese Document Processing Systems In The Republic Of China, Cheng-Kiang Farn Oct 1990

Current Developments In Chinese Document Processing Systems In The Republic Of China, Cheng-Kiang Farn

Journal of East Asian Libraries

No abstract provided.

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The Effect Of Externally Applied Oscillating Electric Fields On The L=1 And L=2 Diocotron Modes In Non-Neutral Plasmas, Ross L. Spencer Oct 1990

The Effect Of Externally Applied Oscillating Electric Fields On The L=1 And L=2 Diocotron Modes In Non-Neutral Plasmas, Ross L. Spencer

Faculty Publications

A high-frequency oscillating electric field can change the properties of diocotron modes in non-neutral plasmas. The effect depends crucially on the azimuthal mode number, m, of the applied field. For m=0, plus or minus 1 there is no effect, and for applied standing waves there is also no effect. But if the applied field has the form of a traveling wave with the norm of m greater than or equal to 2, the frequency of stable diocotron modes can be modified and for the norm of m greater than or equal to 3, the l=2 instability of hollow density profiles …

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Techniques For Cubic Algebraic Surfaces Ii, Thomas W. Sederberg Sep 1990

Techniques For Cubic Algebraic Surfaces Ii, Thomas W. Sederberg

Faculty Publications

A survey of some techniques that may have potential for free-form modeling with algebraic surfaces is continued. Classical results as well as several recent innovations are included. Specific attention is paid to cubic algebraic surfaces, although many of the ideas presented have application to algebraic surfaces of any degree. Topics addressed include piecewise constructions, interpolation to points and space curves, and parameterization.

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Deciphering The Geography Of The Book Of Mormon: Settlements And Routes In Ancient America F. Richard Hauck; An Ancient American Setting For The Book Of Mormon John L. Sorenson, Bruce W. Warren Jul 1990

Deciphering The Geography Of The Book Of Mormon: Settlements And Routes In Ancient America F. Richard Hauck; An Ancient American Setting For The Book Of Mormon John L. Sorenson, Bruce W. Warren

BYU Studies

No abstract provided.

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Techniques For Cubic Algebraic Surfaces I, Thomas W. Sederberg Jul 1990

Techniques For Cubic Algebraic Surfaces I, Thomas W. Sederberg

Faculty Publications

The tutorial presents some tools for free-form modeling with algebraic surfaces, that is, surfaces that can be defined using an implicit polynomial equation f(x, y, z )=0. Cubic algebraic surfaces (defined by an implicit equation of degree 3) are emphasized. While much of this material applies only to cubic surfaces, some applies to algebraic surfaces of any degree. This area of the tutorial introduces terminology, presents different methods for defining and modeling with cubic surfaces, and examines the power basis representation of algebraic surfaces. Methods of forcing an algebraic surface to interpolate a set of points or a space curve …

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Tomlinsonia Stichkania Sp. Nov., A Permineralized Grass From The Pliocene To (?)Pleistocene China Ranch Beds In Sperry Wash, California, William D. Tidwell, E. M. V. Nambudiri Jun 1990

Tomlinsonia Stichkania Sp. Nov., A Permineralized Grass From The Pliocene To (?)Pleistocene China Ranch Beds In Sperry Wash, California, William D. Tidwell, E. M. V. Nambudiri

Faculty Publications

Permineralized specimens of grasses assignable to Tomlinsonia as a new species Tomlinsonia stichkania occur in the China Ranch beds of Pliocene to possible Pleistocene age in Sperry Wash in the Alexander Hills of southeastern California. The round culm of these grasses is generally solid or occasionally hollow with collateral vascular bundles in the distinct outer and indistinct inner rings. Two-ranked leaf sheaths alternately encircle and overlap the culm. Ridges and furrows occur in the abaxial surfaces of the sheaths. The epidermis of the leaf sheaths is similar to that of the culm. The leaf lamina consists of a three-layered mesophyll. …

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