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Articles 1 - 30 of 35
Full-Text Articles in Physical Sciences and Mathematics
Power Law Exponents For A Spreading Front And Growing Interface In An Irreversible Wetting, Evan Willett, Ras B. Pandey
Power Law Exponents For A Spreading Front And Growing Interface In An Irreversible Wetting, Evan Willett, Ras B. Pandey
Faculty Publications
Using computer simulations, the power-law behavior of the interface growth of a spreading fluid is studied in a two-dimensional lattice model. The interface width exponent ν and the dynamical exponent k for the evolution of the front are consistent with their dynamical scaling relation. The magnitude of these exponents seems to depend upon the nature of the substrate and the concentration of the carriers of the wetting fluid.
In Situ Infrared Evidence For The Electrochemical Incorporation Of Hydrogen Into Si And Ge, K. C. Mandal, F. Ozanam, J.-N. Chazalviel
In Situ Infrared Evidence For The Electrochemical Incorporation Of Hydrogen Into Si And Ge, K. C. Mandal, F. Ozanam, J.-N. Chazalviel
Faculty Publications
No abstract provided.
Purification And Characterization Of A Dna Polymerase From The Cyanobacterium Anacystis Nidulans R2, Hsiu-Jin Lin, Gordon C. Cannon, Sabine Heinhorst
Purification And Characterization Of A Dna Polymerase From The Cyanobacterium Anacystis Nidulans R2, Hsiu-Jin Lin, Gordon C. Cannon, Sabine Heinhorst
Faculty Publications
A DNA polymerase has been highly purified from Anacystis nidulans R2. Electrophoretic analysis in sodium dodecyl sulfate-polyacrylamide gels revealed that the final fraction contains three bands of Mr 107,000, 93,000, and 51,000, respectively. Analysis of purified DNA polymerase activity in situ indicates that of the three polypeptides the Mr 107,000 species has the catalytic activities. The native molecular weight of the enzyme was estimated by glycerol gradient sedimentation to be 100,000. The enzyme has an absolute requirement for a divalent cation. Mg2+ can be replaced with Mn2+, but the DNA polymerase is less active. Potassium …
Self-Calibrating Position-Sensitive Silicon Detectors, J. T. Walton, H. A. Sommer, Gordon J. Wozniak, Graham F. Peaslee, D. R. Bowman, W. L. Kehoe, A. Moroni
Self-Calibrating Position-Sensitive Silicon Detectors, J. T. Walton, H. A. Sommer, Gordon J. Wozniak, Graham F. Peaslee, D. R. Bowman, W. L. Kehoe, A. Moroni
Faculty Publications
Position-sensitive silicon detectors with discrete position output signal levels, which have been developed for heavy ion reaction studies at the Lawrence Berkeley Laboratory are discussed. The detectors, both 300- and 5000-μm thick, for use in ΔE-E telescopes, use a series of high and low conductivity strips on the detector p+ contact to produce a position signal with 15 discrete levels. Since the position of the signals from the strips is known, the detectors are self-calibrating against position nonlinearities. Some aspects of the fabrication of both the 300- and 5000-μm detectors are discussed, along with their operating characteristics. Illustrative experimental results …
Degree Of Adaptive Approximation, Ronald A. Devore, Ming Yu Xiang
Degree Of Adaptive Approximation, Ronald A. Devore, Ming Yu Xiang
Faculty Publications
We obtain various estimates for the error in adaptive approximation and also establish a relationship between adaptive approximation and free-knot spline approximation.
The Effect Of Externally Applied Oscillating Electric Fields On The L=1 And L=2 Diocotron Modes In Non-Neutral Plasmas, Ross L. Spencer
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 …
Computer Simulation Study Of Conductivity In A 2-Dimensional Binary Fluid Mixture, Ras B. Pandey
Computer Simulation Study Of Conductivity In A 2-Dimensional Binary Fluid Mixture, Ras B. Pandey
Faculty Publications
A computer-simulation model is introduced to study the transport properties of a binary fluid mixture in which the constituents of one fluid (the tracer particles) carry charges in a linear charge-density gradient in the background charge of the second fluid. In the steady-state equilibrium, an effective conductivity σc(p,r) is estimated as a function of the carrier concentration p and the range of interactions r. The conductivity is observed to vary nonmonotonically with the concentration p, and it exhibits a maximum at a characteristic value pc. The conductivity decreases when the …
Techniques For Cubic Algebraic Surfaces Ii, Thomas W. Sederberg
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.
Theory Of Light Scattering By A Nonequilibrium Binary Mixture, J.C. Nieuwoudt, B.M. Law
Theory Of Light Scattering By A Nonequilibrium Binary Mixture, J.C. Nieuwoudt, B.M. Law
Faculty Publications
A binary mixture subject to a large temperature gradient is studied. Solutions of the evolution equations for the time-dependent fluctuation correlations are obtained using mode-coupling theory subject to the assumption that the mixture is not close to a critical point. From these results predictions for the light-scattering spectrum at the Rayleigh and Brillouin lines are made. The temperature gradient is shown to cause a large enhancement of the scattering amplitude at the Rayleigh line, whereas the effect at the Brillouin line is found to be small.
Techniques For Cubic Algebraic Surfaces I, Thomas W. Sederberg
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 …
Universal Scaling Of Nonlocal And Local Resistance Fluctuations In Small Wires, H. Haucke, S. Washburn, A. D. Benoit, C. P. Umbach, Richard A. Webb
Universal Scaling Of Nonlocal And Local Resistance Fluctuations In Small Wires, H. Haucke, S. Washburn, A. D. Benoit, C. P. Umbach, Richard A. Webb
Faculty Publications
Resistance fluctuations in small metal samples result from coherent transport of the carriers. The wave functions of the carriers extend into regions which are not accessible classically. We have directly measured the length dependence of the nonlocal magnetoresistance fluctuations in Sb and Au wires by studying regions of our samples separated from the classical current path by a distance L which varied from 3Lcphi down to 0.2Lcphi (where Lcphi is the phase coherence length for the carriers in the metal). These fluctuations decay exponentially with L/Lcphi. Measurements along the classical current paths scale more slowly …
Eigenvalue Problems Of Ginzburg–Landau Operator In Bounded Domains, Kening Lu, Xing-Bin Pan
Eigenvalue Problems Of Ginzburg–Landau Operator In Bounded Domains, Kening Lu, Xing-Bin Pan
Faculty Publications
In this paper we study the eigenvalue problems for the Ginzburg–Landau operator with a large parameter in bounded domains in [openface R]2 under gauge invariant boundary conditions. The estimates for the eigenvalues are obtained and the asymptotic behavior of the associated eigenfunctions is discussed. These results play a key role in estimating the critical magnetic field in the mathematical theory of superconductivity.
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
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. …
Consistency And Generalization In Incrementally Trained Connectionist Networks, Tony R. Martinez
Consistency And Generalization In Incrementally Trained Connectionist Networks, Tony R. Martinez
Faculty Publications
This paper discusses aspects of consistency and generalization in connectionist networks which learn through incremental training by examples or rules. Differences between training set learning and incremental rule or example learning are presented. Generalization, the ability to output reasonable mappings when presented with novel input patterns, is discussed in light of the above learning methods. In particular, the contrast between humming distance generalization and generalizing by high order combinations of critical variables is overviewed. Examples of detailed rules for an incremental learning model are presented for both consistency and generalization constraints.
Norms Of Positive Operators On Lp-Spaces, Ralph Howard, Anton R. Schep
Norms Of Positive Operators On Lp-Spaces, Ralph Howard, Anton R. Schep
Faculty Publications
No abstract provided.
Interactive Morphometrics From Three-Dimensional Surface Images, William A. Barrett, Shawn C. Becker
Interactive Morphometrics From Three-Dimensional Surface Images, William A. Barrett, Shawn C. Becker
Faculty Publications
Techniques have been developed for extracting three-dimensional (3D) measurements directly and interactively from 3D representations of surface anatomy. In order to obtain 3D measurements the anatomical surface is interrogated directly through the use of morphometric tools. Morphometric tools include points, 3D graphical "probes", and logical sectioning functions which interact with the surface through depth buffer compositing operations. Tools are interactively positioned on or through the surface to measure surface dimensions and partial volumes, or to define intersecting functions which allow surface anatomy to be visualized in the context of surrounding anatomy. Visualization is also enhanced because tools reveal much pertaining …
Production And Deexcitation Of Hot Nuclei In Collisions Of 27 Mev/Nucleon 40ar + 238u, D. Jacquet, Graham F. Peaslee, John M. Alexander, B. Borderie, E. Duek, J. Galin, D. Gardes, C. Grégorie, D. Guerreau, H. Fuchs, M. Lefort, M. F. Rivet, X. Tarrago
Production And Deexcitation Of Hot Nuclei In Collisions Of 27 Mev/Nucleon 40ar + 238u, D. Jacquet, Graham F. Peaslee, John M. Alexander, B. Borderie, E. Duek, J. Galin, D. Gardes, C. Grégorie, D. Guerreau, H. Fuchs, M. Lefort, M. F. Rivet, X. Tarrago
Faculty Publications
Hot nuclei, produced in the reaction 1080 MeV 40Ar+238U, have been studied by means of the light charged particles emitted in coincidence with fission fragments. A dominant fraction of the light charged particles emitted in the backward hemisphere (60%, 75%, 80% and 85% for 1,2,3H and 4He, respectively) comes from evaporation from a composite nucleus prior to scission. Careful analysis of the cross sections and energy spectra of these evaporated particles yields several properties of the hot nuclear emitters: (i) they are thermalized with an average temperature of 4.0–4.6 MeV, (ii) they are quite deformed (mean axis ratio ) and …
Chloroplast And Mitochondrial: Dna Polymerases From Cultured Soybean Cells, Sabine Heinhorst, Gordon C. Cannon, Arthur Weissbach
Chloroplast And Mitochondrial: Dna Polymerases From Cultured Soybean Cells, Sabine Heinhorst, Gordon C. Cannon, Arthur Weissbach
Faculty Publications
DNA polymerases were purified from chloroplasts and mitochondria of cultured Glycine max cells. The chloroplast enzyme exists in two forms which are indistinguishable from each other biochemically. All three organellar enzymes have an estimated molecular weight of 85,000 to 90,000 and prefer poly(rA)dT12-18 over activated DNA as a template in vitro. Maximum activity of the chloroplast and mitochondrial DNA polymerases requires KCI and a reducing agent, and the enzymes are completely resistant to inhibitors of DNA polymerase a. Taken together, these properties classify the soybean organellar enzymes as DNA polymerases y. A unique feature that distinguishes the plant enzymes from …
A Scale Of Linear Spaces Related To The Lp Scale, S J. Dilworth
A Scale Of Linear Spaces Related To The Lp Scale, S J. Dilworth
Faculty Publications
No abstract provided.
The Extended Tracking Network And Indications Of Baseline Precision And Accuracy In The North Andes, Jeffrey T. Freymueller, James N. Kellogg
The Extended Tracking Network And Indications Of Baseline Precision And Accuracy In The North Andes, Jeffrey T. Freymueller, James N. Kellogg
Faculty Publications
The CASA UNO Global Positioning System (GPS) experiment (January-February 1988) included an extended tracking network which covered three continents in addition to the network of scientific interest in Central and South America. The repeatability of long baselines (400-1000 km) in South America is improved by up to a factor of two in the horizontal vector baseline components by using tracking stations in the Pacific and Europe to supplement stations in North America. In every case but one, the differences between the mean solutions obtained using different tracking networks was equal to or smaller than day-to-day rms repeatabilities for the same …
First Gps Baseline Results From The North Andes, James N. Kellogg, Jeffrey T. Freymueller, Timothy H. Dixon, Ruth E. Neilan, Clemente Ropain U., Sergio Camargo M., Benjamin Fernandez Ch., James L. Stowell, Anibal Salazar, Jaime Mora V., Luis Espin, Vernon Perdue, Leonard Leos
First Gps Baseline Results From The North Andes, James N. Kellogg, Jeffrey T. Freymueller, Timothy H. Dixon, Ruth E. Neilan, Clemente Ropain U., Sergio Camargo M., Benjamin Fernandez Ch., James L. Stowell, Anibal Salazar, Jaime Mora V., Luis Espin, Vernon Perdue, Leonard Leos
Faculty Publications
The CASA UNO GPS (Global Positioning System) experiment (January-February 1988) has provided the first epoch baseline measurements for the study of plate motions and crustal deformation in and around the North Andes. Two dimensional horizontal baseline repeatabilities are as good as 5 parts in 108 for short baselines (100-1000km), and better than3 parts in 108 for long baselines (>1000km). Vertical repeatabilities are typically 4 -6 cm, with a weak dependence on baseline length. The expected rate of plate convergence across the Colombia Trench is 6-8 cm/yr, which should be detectable by the repeat experiment planned for 1991. …
Central And South America Gps Geodesy- Casa Uno, James N. Kellogg, Timothy H. Dixon
Central And South America Gps Geodesy- Casa Uno, James N. Kellogg, Timothy H. Dixon
Faculty Publications
In January 1988, scientists from over 25 organizations in 13 countries and territories cooperated in the largest Global Positioning System (GPS) campaign in the world to date (Table 1). 43 GPS receivers collected approximately 590 station-days of data in America, Samoa, Australia, Canada, Colombia, Costa Rica, Ecuador, New Zealand, Norway, Panama, Sweden, United States, West Germany, and Venezuela. The experiment was entitled CASA UNO, an acronym for Central and South America -- and uno is the Spanish word for one, designating first epoch measurements. The CASA UNO experiment was the first civilian effort implementing a global GPS satellite tracking network. …
Photoluminescence Studies In Znxcd1-Xte Single Crystals, David D. Allred, Jesus González-Hernández, Elías López-Cruz, Worth P. Allred
Photoluminescence Studies In Znxcd1-Xte Single Crystals, David D. Allred, Jesus González-Hernández, Elías López-Cruz, Worth P. Allred
Faculty Publications
The crystalline quality of ZnxCd1-xTe single crystals prepared by a modified Bridgman method with 0≤x≤0.05 has been analyzed using photoluminescence. The spectrum of a typical sample is dominated by lines originating from the recombination of free and bound excitons. Lines due to free excitons in their ground and first excited states are observed in both the pure CdTe and the mixed crystals. Excitons bound to Dc vacancies are observed in the pure CdTe crystal but not in the mixed crystal. Weaker and broader features appearing at energies below the exciton emission range were associated with transitions involving free-to-bound and bound-to-bound …
On Two Function-Spaces Which Are Similar To L0, S J. Dilworth, D A. Trautman
On Two Function-Spaces Which Are Similar To L0, S J. Dilworth, D A. Trautman
Faculty Publications
No abstract provided.
Inhomogeneous Broadening In Spectral Bands Of Carbonmonoxymyoglobin: The Connection Between Spectral And Functional Heterogeneity, Todd B. Sauke, P. Ormos, A. Ansari, D. Braunstein, B. R. Cowen, H. Fraunfelder, M. K. Hong, I. E. T. Iben, P. J. Steinbach, R. D. Young
Inhomogeneous Broadening In Spectral Bands Of Carbonmonoxymyoglobin: The Connection Between Spectral And Functional Heterogeneity, Todd B. Sauke, P. Ormos, A. Ansari, D. Braunstein, B. R. Cowen, H. Fraunfelder, M. K. Hong, I. E. T. Iben, P. J. Steinbach, R. D. Young
Faculty Publications
The rebinding kinetics of CO to myoglobin after flash photolysis is nonexponential in time below approximately 180 K; the kinetics is governed by a distribution of enthalpic barriers. This distribution results from inhomogeneities in the protein conformation, referred to as conformational substates. Hole-burning experiments on the Soret and IR CO-stretch bands test the assumption that an inhomogeneous distribution of conformational substates results in inhomogeneously broadened spectra. CO was slowly photolyzed at different wavelengths in the Soret band at 10 K. Both the Soret band and the CO-stretch band A1, centered at 1,945 cm-1, shift during photolysis, demonstrating that different wavelengths …
Lottery Proceeds In California Pay For Installation Of A Ground-Water Monitoring System, June Ann Oberdorfer, J. W. Williams, M. G. Smelser
Lottery Proceeds In California Pay For Installation Of A Ground-Water Monitoring System, June Ann Oberdorfer, J. W. Williams, M. G. Smelser
Faculty Publications
No abstract provided.
A Course In Laboratory And Stockroom Management, John T. Moore
A Course In Laboratory And Stockroom Management, John T. Moore
Faculty Publications
No abstract provided.
Rheology Of Aqueous Suspensions Of Polystyrene Latex Stabilized By Grafted Poly(Ethylene Oxide), Harry J. Ploehn, J. W. Goodwin
Rheology Of Aqueous Suspensions Of Polystyrene Latex Stabilized By Grafted Poly(Ethylene Oxide), Harry J. Ploehn, J. W. Goodwin
Faculty Publications
A water-soluble carbodiimide has been used to end-graft aminated poly (ethylene oxide)(PEO) chemically onto colloidal polystyrene particles. Two particle sizes (115 and 347 nm diameter) and two PEO molecular weights (112 000 and 615 000 g mol–1) were combined to give suspensions with four different ratios of polymer layer thickness to particle radius. Electrophoresis demonstrated that the PEO was grafted, not just adsorbed. Dynamic light scattering showed that the adsorbed and grafted layers had similar structures and that non-ionic surfactant perturbed the PEO configurations. Steady shear and oscillatory rheometry indicated that long-ranged polymeric forces between particles governed the …
Annealing Behavior Of The Photoluminescence Lines In Cdte And Znx Cd1-X Te Single Crystals, David D. Allred, A. Reyes-Mena, Jesus González-Hernández, Elías López-Cruz, Worth P. Allred
Annealing Behavior Of The Photoluminescence Lines In Cdte And Znx Cd1-X Te Single Crystals, David D. Allred, A. Reyes-Mena, Jesus González-Hernández, Elías López-Cruz, Worth P. Allred
Faculty Publications
The main lines in the photoluminescence spectra of Zn1Cd1-xTe single crystals grown by a modified Bridgman method in the compositional range of 0≤X≤0.25 have been identified. All crystals show only near-band-edge emission. To assist in the identification, various samples with different compositions were annealed under a Cd atmosphere. In the pure crystals, the prominent (A°, X) bound exciton line, as well as the doublet at longer wavelengths, disappear after the annealing. In contrast, the treatments do not change significantly the PL spectra of the mixed crystals.
Deposition Of Zinc Selenide By Atomic Layer Epitaxy For Multilayer X-Ray Optics, J.K. Shurtleff, David D. Allred, R. T. Perkins, J. M. Thorne
Deposition Of Zinc Selenide By Atomic Layer Epitaxy For Multilayer X-Ray Optics, J.K. Shurtleff, David D. Allred, R. T. Perkins, J. M. Thorne
Faculty Publications
Thin film deposition techniques currently being used to produce multilayer x-ray optics (MXOs) have difficulty producing smooth, uniform multilayers with d-spacings less than about twelve angstroms. We are investigating atomic layer epitaxy (ALE) as an alternative to these techniques. ALE is a chemical vapor deposition technique which deposits an atomic layer of material during each cycle of the deposition process. The thickness of a film deposited by ALE depends only on the number of cycles. Multilayers deposited by ALE should be smooth and uniform with precise d-spacings which makes ALE an excellent technique for producing multilayer x-ray optics. We have …