Physical Sciences and Mathematics Commons^™

A Quasiparticle Trap Assisted Transition Edge Sensor For Phonon Mediated Particle Detection, K. D. Irwin, S. W. Nam, Blas Cabrera, B. Chugg, Betty A. Young

Physics

ABSTRACT We have demonstrated the operation of composite superconducting tungsten and aluminum transition‐edge sensors which take advantage of quasiparticle trapping and electrothermal feedback. We call these devices W/Al QETs (quasiparticle‐trap‐assisted electrothermal feedback transition‐edge sensors). The quasiparticle trapping mechanism makes it possible to instrument large surface areas without increasing sensor heat capacity, thus allowing larger absorbers and reducing phonon collection times. The sensor consists of a 30‐nm‐thick superconducting tungsten thin film with T_c∼80 mK deposited on a high‐purity silicon substrate. The W film is patterned into 200 parallel lines segments, each 2 μm wide and 800 μm long. Eight …

Analysis Of Ladar Range Resolution Enhancement By Sinusoidal Phase Modulation, Leonard T. Masters, Martin B. Mark, Bradley D. Duncan

Electro-Optics and Photonics Faculty Publications

The ability of a ladar system to resolve two or more separate returns from a combined echo is related to the effective correlation bandwidth of the pulse emitted by the ladar system. Phase modulation of an outgoing pulse introduces additional frequency components, which increases the effective correlation bandwidth of the pulse and thus improves the range resolution of the system. In this paper, we discuss the general theoretical basis for achieving improved range resolution using a modulated waveform and a matched filter receiver. We then demonstrate these concepts by considering the particular case of improved range resolution for a sinusoidally …

A Simple Solver For Linear Equations Containing Nonlinear Operators, Norman Ramsey

Department of Computer Science Technical Reports

No abstract provided.

Blending Basic Implicit Shapes Using Trivariate Box Splines, Jörg Peters, Michael Wittman

Department of Computer Science Technical Reports

No abstract provided.

Complexity Of Sequential Pattern Matching Algorithms, Mireille Régnier, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

Multi-View Access Protcols For Large-Scale Replication, Xiangning (Sean) Liu, Abdelsalam (Sumi) Helal, Bharat K. Bhargava

Department of Computer Science Technical Reports

No abstract provided.

Optimal P-Cyclic Sor For Complex Spectra, S. Galanis, A. Hadjidimos, D. Noutsos

Department of Computer Science Technical Reports

No abstract provided.

Sequence Alignment In Molecular Biology, Alberto Apostolico, Raffaele Fiancarlo

Department of Computer Science Technical Reports

No abstract provided.

The Magnitude And Persistence Of Soil No, N2o, Ch4, And Co, Fluxes From Burned Tropical Savanna In Brazil, M Poth, Iris C. Anderson, Et Al

VIMS Articles

Among all global ecosystems, tropical savannas are the most severely and extensively affected by anthropogenic burning. Frequency of fire in cerrado,a type of tropical savanna covering 25% of Brazil, is 2 to 4 years. In 1992 we measured soil fluxes of NO, N2O, CH4, and CO2 from cerrado sites that had been burned within the previous 2 days, 30 days, 1 year, and from a control site last burned in 1976. NO and N2O fluxes responded dramatically to fire with the highest fluxes observed from newly burned soils after addition of water. Emissions of N-trace gases after burning were of …

Device And Physical Data Independence For Multimedia Presentations, Richard Staehli, Jonathan Walpole, David Maier

Computer Science Faculty Publications and Presentations

Multimedia computing promises access to any type of visual or aural medium on the desktop. But in this networked future, will every type of media be accessible from every terminal device? Current multimedia standards do not allow content that is authored for high-bandwidth workstations to scale down for low-bandwidth applications. The problem is that application requests are commonly interpreted as requests for the highest possible quality and resource overloads are handled by ad hoc methods. We can begin to solve this problem by specifying Quality of Service (QOS) requirements based on functionality rather than on content encoding and device capabilities.

Spin Polarization Of The Conduction Bands Of Gd(0001)*, Dongqi Li, J. Pearson, S.D. Bader, D. N. Mcilroy, C. Waldfried, Peter A. Dowben

Peter Dowben Publications

Angle- and spin-resolved photoemission was utilized to investigate the 5d bulk bands and the surface state of Gd(0001) in the temperature range of 130 - 350 K. The bulk bands at 1-2 eV below the Fermi energy E_F show Stoner-like behavior, while the temperature dependence of the surface state near E_F indicates spin-mixing behavior due to fluctuating local 5d moments. The secondary electron spectra of the Gd surfaces both before and after initial oxygen adsorption show a polarization dip at low kinetic energies due to the extra scattering channel for minority electrons via the unoccupied 4ƒ level. The …

Magnetic Properties And Structure Of Fe/Pt Thin Films, C.P. Luo, David J. Sellmyer

David Sellmyer Publications

The structural transfqmation from fcc to fct and relevant magnetic properties of initially multilayered Fe/Pt films were studied. When the as-deposited FePt films were annealed at the temperature of 300°C and up, the fct-phase was formed. Rather square hysteresis loops and large coercivities were measured from the annealed films. The films annealed at 300°C retain a layered structure.

A Magnetic, Neutron-Diffraction, And Mössbauer Spectral Study Of The Ce₂Fe₁₇₋ₓsiₓ Solid Solutions, D. P. Middleton, Sanjay R. Mishra, Gary J. Long, Oran Allan Pringle, Zhongbo Hu, William B. Yelon, Fernande Grandjean, K. H. J. Buschow

Chemistry Faculty Research & Creative Works

The magnetic properties of a series of Ce₂Fe_17-xSi_x solid solutions with x equal to 0.0, 0.23, 0.4, 0.6, 0.8, 1.02, 1.98, and 3.20 have been studied by magnetic measurements, neutron diffraction, and Mössbauer spectroscopy. An x-ray-diffraction study indicates that the compounds adopt the rhombohedral Th₂Zn ₁₇-type structure. The substitution of silicon for iron in Ce ₂Fe₁₇ leads to a contraction of the a axis by 0.2%, an expansion of the c axis by 0.2%, and a consequent reduction of the unit-cell volume by about 0.2% per substituted silicon. Magnetization studies …

On The Equivalence Of Upward And Downward Inheritance Reasoners, Krishnaprasad Thirunarayan

Kno.e.sis Publications

In this paper, we analyze systematically the downward (property flow) and the upward (individual flow) views of inheritance for different categories of inheritance networks. We observe that both these views assign the same meaning to tree-structured hierarchies, and explain the divergence in the interpretation of more general networks in terms of their expressive power. This simple analysis sheds light on the inherent nature of nonmonotonic inheritance and can form the basis for the design of efficient algorithms for certain classes of queries. In addition, we describe the notion of preferential inheritance to specify additional conflict resolution information that can be …

High Resolution Electron Microscopy And Nano-Probe Study Of Cosm/Cr Films, Yi Liu, David J. Sellmyer, B. W. Robertson, Z.S. Shan, Sy_Hwang Liou

Sy-Hwang Liou Publications

The crystal structure of the crystallites in CoSm thin films deposited on Cr underlayer was studied by nanodiffraction and high resolution electron microscopy (HREM). It was found that the crystallites have a closed-packed structure. Some nanodiffraction patterns taken from different crystallites using a two nanometer probe can be indexed by two layer stacking AB (HCP structure), three layer stacking ABC (FCC structure), and four layer stacking ABAC (double hexagonal structure), suggesting that a particular local stacking mode could exist. [112^-0] HREM images confirmed that stacking sequence changes within one crystallite. In local regions, random stacking, and unit cells …

Image Restoration Of Dispersion-Degraded Images From A Liquid-Crystal Beam Steerer, Ronald J. Broessel, Vince Dominic, Russell C. Hardie

Electrical and Computer Engineering Faculty Publications

Liquid-crystal arrays represents one of the first practical technologies capable of steering light by electronic control only. We use such a device to steer the field of view of a broadband imaging sensor. Unfortunately, dispersion degrades the image quality by smearing out details in the image and by introducing multiple diffraction orders (echoes) at the detector plane. We present a method to compensate for these unwanted effects and thus restore the broadband images obtained with the beam steerer. We use the beam-propagation method to find the wavelength-dependent impulse response, from which we determine the appropriate Wiener filter. When training data …

Groundwater Study: Toyota Motor Manufacturing, Usa Georgetown, Kentucky, Gary Felton, Lyle V. A. Sendlein, Teri Dowdy, Daryl Hines

KWRRI Research Reports

An eighteen month study of the Toyota Motor Manufacturing (TMM) plant site and the surrounding area was undertaken. The basic charge for this project was to characterize the groundwater that is potentially impacted by the TMM plant site. This included occurrence, flow direction, and, if possible, velocity. Because the area is karstified (has sinkholes, springs, caves, etc.) surface water and groundwater are intimately connected and, hence, surface water was frequently an important component of this work.

Data from TMM construction plans and monitoring work done subsequent to construction were elicited from the various repositories within the TMM infrastructure. Aerial color …

Steady-State Kinetics Of Br(2P1/2) Yields Co2(101) Electronic-To-Vibrational Energy Transfer Laser System, Stephen J. Karis

Theses and Dissertations

Steady state photolysis experiments were conducted to gain information relevant to the construction of a continuous wave electronic to vibrational pumped infrared laser. An Ar⁺ laser =488 µm) was used to produce the electronically excited state Br(²P_1/2) (Br^*) via photolysis of molecular bromine. Energy was then transferred to the near resonant vibrational state CO₂(101) (CO₂) via the collisional quenching of Br^* by CO₂. The dependence of the 2.71 µm Br^* and 4.3 µm CO₂ emissions on CO₂ pressure was measured, as well as …

On The Impact Of Forgetting On Learning Machines, Rūsiņš Freivalds, Efim Kinber, Carl H. Smith

School of Computer Science & Engineering Faculty Publications

People tend not to have perfect memories when it comes to learning, or to anything else for that matter. Most formal studies of learning, however, assume a perfect memory. Some approaches have restricted the number of items that could be retained. We introduce a complexity theoretic accounting of memory utilization by learning machines. In our new model, memory is measured in bits as a function of the size of the input. There is a hierarchy of learnability based on increasing memory allotment. The lower bound results are proved using an unusual combination of pumping and mutual recursion theorem arguments. For …

Magnetic And Magneto-Optical Properties Of MnXCubi ( X =0.75 - 3.5 ) Films†, Jian Chen, K. Wierman, Roger D. Kirby, David J. Sellmyer

Department of Physics and Astronomy: Faculty Publications

Abstract - Magnetic and magneto-optical properties of Mn_xCuBi ( x = 0.75 - 3.5) thin films are presented. With increasing Mn concentration x, the perpendicular anisotropy constant (K_u), the remanence squareness (S = M_r/M_s) and the coercivity (H_c ), of the perpendicular hysteresis loop increase. Remanence squareness as high as 0.95 has been obtained. Kerr rotation (Ө_k) and ellipticity (η_k) spectra from all samples measured from substrate side are similar, with Ө_k exhibiting a broad peak in the blue wavelength region with maximum Kerr rotation up …

Recurrences Associated With A Classical Orbit In The Node Of A Quantum Wave Function, John A. Shaw, John B. Delos, Michael Courtney, Daniel Kleppner

Arts & Sciences Articles

Absorption spectra of atoms in magnetic fields reveal recurrences: manifestations of classical orbits (or quantum wave packets) that go out from the atom and later return. A formula from closed-orbit theory asserts that if the orbit lies on a node of the outgoing wave function, then the strength of the recurrence is zero. New quantum calculations, however, show that the recurrence strength is nonzero, though small. We derive a semiclassical formula for the recurrence strength associated with a classical orbit at a node of the quantum wave function. This formula is compared to the quantum mechanical calculation. Compared to …

Liquid Crystal Displays, Peter J. Collings

Physics & Astronomy Faculty Works

No abstract provided.

Heterodyne Ladar System Efficiency Enhancement Using Single-Mode Optical Fiber Mixers, Donald K. Jacob, Martin B. Mark, Bradley D. Duncan

Electro-Optics and Photonics Faculty Publications

A theoretical performance analysis of a heterodyne ladar system incorporating a single-mode fiber receiver has been performed. For our purposes, the performance parameters of interest are the coupling and mixing efficiency of the ladar receiver, as they relate to the overall system carrier-to-noise ratio. For a receiver incorporating a single-mode fiber mixer, the received and local-oscillator fields are matched both spatially and temporally at the detector, yielding 100% mixing efficiency. We have therefore focused our efforts on determining an expression for the efficiency with which a diffuse return from a purely speckle target can be coupled into the receiving leg …

Center For Sustainable Agricultural Systems Newsletter, November/December 1995

Center for Sustainable Agricultural Systems: Newsletters (1993-2000)

Contents:

North Central Institute for Sustainable Systems Pilot Project Launched

An Ecocentric View of Future Research

Diversity in Human and Ecological Systems

Politics of Sustainable Agriculture

Impact Project Gets Additional Funding

Participation a New Research Direction in Finland

Nebraska Participates in Whole Farm Conservation Planning Pilot

New Internship in Food Production/Marketing

USDA-DOE Pact Combines Scientific Energies

Interested in Becoming Certified Organic?

Magnetic And Magneto-Optical Properties Of MnXCubi ( X =0.75 - 3.5 ) Films, Jian Chen, K. Wierman, Roger D. Kirby, David J. Sellmyer

Department of Physics and Astronomy: Faculty Publications

Magnetic and magneto-optical properties of Mn_xCuBi ( x = 0.75 - 3.5) thin films are presented. With increasing Mn concentration x, the perpendicular anisotropy constant (K_u the remanence squareness (S = M_r/M_s) and the coercivity (H_c)the perpendicular hysteresis loop increase. Remanence squareness as high as 0.95 has been obtained. Kerr rotation (θ_k) and ellipticity (η_k) spectra from all samples measured from substrate side are similar, with θ_k exhibiting a broad peak in the blue wavelength region with maximum Kerr rotation up to 0.7 degrees.

Environmental Regulation Of Oil And Gas Development On Tribal Lands: Who Has The Authority?, Richard B. Collins, Tom Shipps, Marla Williams, University Of Colorado Boulder. Natural Resources Law Center

Environmental Regulation of Oil and Gas Development on Tribal Lands: Who Has the Authority? (November 1)

14 pages.

Collection of 3 papers presented at the Hot Topics in Natural Resources Law program held on Nov. 1, 1995.

Includes bibliographical references.

Contents:

Environmental regulation of oil and gas development on tribal lands : who has authority? / Richard Collins -- Environmental regulation of energy resource development on Indian reservation land / Tom Shipps -- Colorado Oil and Gas [Conservation] Commission jurisdiction over environmental matters on Indian lands / Marla Williams

Jurisdiction to regulate the environmental impacts of oil and gas development on the reservation has been contested by tribes, the state, private land owners and federal agencies. …

No-Till Sowing Systems In North America With Relevance To Western Australia, K J. Bligh

Resource management technical reports

No abstract provided.

Intelligent Control Of Vehicles: Preliminary Results On The Application Of Learning Automata Techniques To Automated Highway System, Cem Unsal, John S. Bay, Pushkin Kachroo

Electrical & Computer Engineering Faculty Research

We suggest an intelligent controller for an automated vehicle to plan its own trajectory based on sensor and communication data received. Our intelligent controller is based on an artificial intelligence technique called learning stochastic automata. The automaton can learn the best possible action to avoid collisions using the data received from on-board sensors. The system has the advantage of being able to work in unmodeled stochastic environments. Simulations for the lateral control of a vehicle using this AI method provides encouraging results.

Customizable Operating Systems, Jonathan Walpole, Crispin Cowan, Andrew P. Black, Jon Inouye, Calton Pu, Shanwei Cen

Computer Science Faculty Publications and Presentations

A customizable operating system is one that can adapt to improve its functionality or performance. The need for customizable and application-specific operating systems has been recognized for many years, but they have yet to appear in the commercial market. This paper explores the notion of operating system customizability and examines the limits of existing approaches. The paper begins by surveying system structuring approaches for the safe and efficient execution of customizable operating systems. Then it discusses the burden that existing approaches impose on application software, and explores techniques for reducing this burden. Finally, support for customizability in the Synthetix project …

Quality Of Service Specification For Multimedia Presentations, Richard Staehli, Jonathan Walpole, David Maier

Computer Science Faculty Publications and Presentations

The bandwidth limitations of multimedia systems force tradeoffs between presentation data fidelity and real-time performance. For example, digital video is commonly encoded with lossy compression to reduce bandwidth and frames may be skipped during playback to maintain synchronization. These tradeoffs depend on device performance and physical data representations that are hidden by a database system. If a multimedia database is to support digital video and other continuous media data types, we argue that the database should provide a Quality of Service (QOS) interface to allow application control of presentation timing and information loss tradeoffs.

This paper proposes a data model …