Physical Sciences and Mathematics Commons^™

Longitudinal Nmr Relaxation Of Degenerate 2-D 3he In 4he Films, Robert Hallock, D. T. Sprague, N. Alikacem

Robert Hallock

The NMR spin-lattice relaxation time T1 of a degenerate submonolayer coverage of 3He in a thin adsorbed 4He film has been measured. As a function of 4He coverage, T1 exhibits a maximum and undergoes a change in temperature dependence at a coverage near that of the superfluid transition in the underlying 4He film. Two relaxation mechanisms contribute to the observed T1.

Linear Tc Depression In Mg Doped Yba2cu3o7-X, Robert Hallock, W. M. Tiernan

Robert Hallock

We report resistivity-versus-temperature measurements performed on polycrystalline pellets of YBa2(Cu1-xMgx)3O7-δ made using the polymer-metal-complex precursor method. Tc was found to decrease linearly with increasing Mg doping in the range x=8.6×10-4 to 8.6×10-3 with slope -1400 K/x; the normal-state resistivity and the superconducting transition width showed little or no change. Mg was found to have a maximum solubility in YBa2(Cu1-xMgx)3O7-δ of x~=9×10-3.

72. Professor Cristofor I. Simionescu On His 70th Birthday, Otto Vogl, Ioan I. Negulescu

Otto Vogl

No abstract provided.

Elucidation Of Electronic Structure By The Analysis Of Hyperfine Interactions: The Mnh A 7-Pi - X 7-Sigma(+) (0,0) Band, Thomas Varberg, R. W. Field, A. J. Merer

Thomas D. Varberg

No abstract provided.

Determination Of Rate Distributions From Kinetic Experiments, Todd B. Sauke, P. J. Steinback, K. Chu, H. Frauenfelder, J. B. Johnson, D. C. Lamb, G. U. Nienhaus, R. D. Young

Todd B. Sauke

Rate processes in proteins are often not adequately described by simple exponential kinetics. Instead of modeling the kinetics in the time domain, it can be advantageous to perform a numerical inversion leading to a rate distribution function f(lambda). The features observed in f(lambda) (number, positions, and shapes of peaks) can then be interpreted. We discuss different numerical techniques for obtaining rate distribution functions, with special emphasis on the maximum entropy method. Examples are given for the application of these techniques to flash photolysis data of heme proteins.

Nonequilibrium Processes In Polymers Undergoing Interchange Reactions. Part 2: Reaction-Diffusion Processes, Alejandro Garcia, J. Pojman, D. Kondepudi, C. Van De Broeck

Alejandro Garcia

A reactiodffusion system of polymers undergoing interchange reactions is studied. The equation that describes the dynamics of the system is similar to the Boltzmann equation for a gas of hard spheres. We consider a one-dimensionsl system in which the average length and the concentrations at the boundaries are fixed. The resulting steady states are obtained analytically and with numerical integration of equations obtained by using a local equilibrium approximation. Monte Carlo simulations of experimentally realizable conditions were performed and compared. The results reveal a nonlinear distribution of molecular concentration and mass. The entropy of the polymer distributions is calculated as …

Competition Between Generic And Nongeneric Fronts Inenvelope Equations, James A. Powell, A. C. Newell, C. K. R. T. Jones

James A. Powell

Arguments are presented for understanding the selection of the speed and the nature of the fronts that join stable and unstable states on the supercritical side of first-order phase transitions. It is suggested that from compact support, nonpositive-definite initial conditions, observable front behavior occurs only when the asymptotic spatial structure of a trajectory in the Galilean ordinary differential equation (ODE) corresponds to the most unstable temporal mode in the governing partial differential equation (PDE). This selection criterion distinguishes between a "nonlinear" front, which has its origin in the first-order nature of the bifurcation, and a "linear" front. The nonlinear front …

Ab Initio Study Of The Intermolecular Potential Of Ar–H2o, G. Chalasinski, M. M. Szczesniak, Steve Scheiner

Steve Scheiner

The combination of supermolecular Møller–Plesset treatment with the perturbation theory of intermolecular forces is applied in the analysis of the potential‐energy surface of Ar–H₂O. The surface is very isotropic with the lowest barrier for rotation of ∼35 cm⁻¹ above the absolute minimum. The lower bound for D_e is found to be 108 cm⁻¹ and the complex reveals a very floppy structure, with Ar moving freely from the H‐bridged structure to the coplanar and almost perpendicular arrangement of the C₂ –water axis and the Ar–O axis, ‘‘T‐shaped’’ structure. This motion is almost isoenergetic (energy change …

Ab Initio Study Of Intermolecular Potential Of H2o Trimer, G. Chalasinski, M. M. Szczesniak, P. Cieplak, Steve Scheiner

Steve Scheiner

Nonadditive contribution to the interaction energy in water trimer is analyzed in terms of Heitler–London exchange, SCF deformation, induction and dispersion nonadditivities. Nonadditivity originates mainly from the SCF deformation effect which is due to electric polarization. However, polarization does not serve as a universal mechanism for nonadditivity in water. In the double‐donor configuration, for example, the Heitler–London exchange contribution is the most important and polarization yields the wrong sign. Correlation effects do not contribute significantly to the nonadditivity. A detailed analysis of the pair potential is also provided. The present two‐body potential and its components are compared to the existing …

Theoretical Vibrational Study Of Fx...Nh3 (X=H, D, Li) Complexes, Y. Bouteiller, Z. Latajka, H. Ratajczak, Steve Scheiner

Steve Scheiner

This paper presents the first ab initio attempt to construct the stretching fundamentals ν_FX and ν_F...N (X=H, D, Li) in the FX...NH₃ complexes taking into account the mechanical anharmonicity. A potential‐energy surface V(r_FX,R_F...N) grid was generated at the self‐consistent‐field and second‐order Møller–Plesset levels. The coefficients fitting the potential‐energy surface up to the fourth order have been used to compute the ν_FX and ν_F...N stretching modes. The vibrational problem is solved by means of a variational treatment which includes the effects of mechanical …

Effect Of Intermolecular Orientation Upon Proton Transfer Within A Polarizable Medium, Steve Scheiner, X. Duan

Steve Scheiner

Ab initio calculations are used to investigate the proton transfer process in bacteriorhodopsin. HN = CH₂ serves as a small prototype of the Schiff base while HCOO^- models its carboxylate-containing counterion and HO^- the hydroxyl group of water of tyrosine, leading to the HCOO^-.H⁺.NHCH₂ and HO^-.H⁺.NHCH₂ complexes. In isolation, both complexes prefer a neutral pair configuration wherein the central proton is associated with the anion. However, the Schiff base may be protonated in the former complex, producing the HCOO^-.⁺HNHCH₂ ion pair, when …

The (First) Three B’S Of The Skyrme Model, Alec Schramm

Alec J Schramm

No abstract provided.

Higgs Boson Production In Peripheral Heavy-Ion Collisions: Coherent Double-Pomeron Exchange, Alec Schramm, Berndt Muller

Alec J Schramm

Higgs boson production by coherent double-pomeron exchange in peripheral nuclear collisions at energies of several TeV per nucleon is calculated. It is shown that a trigger on quasi-elastic nuclear collisions strongly suppresses the cross section. The analogous two-photon process is predicted to dominate for collisions of heavy nuclei.

Digital-Image-Based Study Of Circular Holes In An Elastic Matrix, Anthony Day, K. Snyder, E. Garboczi, M. Thorpe

Anthony Roy Day

No abstract provided.

The Development Of An Industrial Waste Regulatory Program, John Dernbach, William Pounds

John C. Dernbach

No abstract provided.

Foundations Of Fuzzy Sets, Lawrence Stout, Ulrich Höhle

Lawrence N. Stout

This paper gives an overview of the origins of fuzzy set theory and the problems for the foundations of fuzzy sets arising from those origins and current practice. It then gives detailed accounts of categorical approaches using a closed structure to capture the fuzzy AND connective. Within these categories weak forms of subobject representations provide an internal second order logic. An approach to fuzzy real numbers and fuzzy topology is included to illustrate the use of this internal; second order theory.

A Symmetric Porosity Conjecture Of Zajícek, Karen Saxe, P. Humke, M. Evans

Karen Saxe

No abstract provided.

Reductions Of Graphs And Spanning Eulerian Subgraphs, Zhi-Hong Chen

Zhi-Hong Chen

A Survey Of Fuzzy Set And Topos Theory, Lawrence Stout

Lawrence N. Stout

This paper is a comparison and contrast of approaches to many-valued mathematics offered by Fuzzy Set theory and topos theory. It gives a survey of the categorical foundations of Fuzzy Set theory and related topoi. Topoi are not a basis for Fuzzy Set theory but they do suggest appropriate directions to go and questions to ask for a synthesis which does provide a foundation. One possible structure which has a topos-like internal logic and the, rich variety of logical connectives used in fuzzy sets is included.

Acquisition Of An Electron Probe Microanalyzer, Andrea Koziol, Robert Wintsch, Michael Dorais, Edward Ripley, Enrique Merino

Andrea M. Koziol

Solving Ill-Posed Problems With Artificial Neural Networks, Arun D. Kulkarni

Arun Kulkarni

Asymptotic Behavior Of Solutions Of Functionally Perturbed Nonoscillatory Second Order Differential Equations, William F. Trench

William F. Trench

No abstract provided.

Universal Conductivity Curve For A Plane Containing Random Holes., E. J. Garboczi, M. F. Thorpe, M. S. Devries, Anthony Roy Day

Anthony Roy Day

This paper examines the general percolation problem of cutting randomly centered insulating holes in a two-dimensional conducting sheet, and explores how the electrical conductivity sigma decreases with the remaining area fraction. This problem has been studied in the past for circular, square, and needlelike holes, using both computer simulations and analog experiments. In this paper, we extend these studies by examining cases where the insulating hole is of arbitrary shape, using digital-image-based numerical techniques in conjunction with the Y- [nabla] algorithm. We find that, within computational uncertainty, the scaled percolation threshold, xc=nc=5.9±0.4, is a universal quantity for all the cases …

Review Essay Of Two Books On The History Of Science, Charles Kay Smith

Charles Kay Smith

Contrary to what I was taught in high school in the mid-1940s, science is no longer defined as an inductive methodology for immaculately conceiving culture-free truth after sifting through a huge data base of objective facts. For without some prior hypothesis to guide her, a scientist would not be able to decide which facts were relevant. Nowadays hypotheses can come from anywhere in the imagination or culture within which the scientist is working. The importance of a scientific hypothesis is that it be framed in such a way that it can be falsified when tested. Science now has a history …

Http://Www.Healthandfitnesshop.Com/Dermavix-Philippines/, James Castillo

James Castillo

Jual Obat Aborsi Medan Kota Medan Sumatra Barat Silahkan Fon 082242266717, Acep Shop

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What's The Sleepgram Pillows Made Of ?, Jmes Modmd

jmes modmd

Matrix-Infrared Spectra Of Structural Isomers Of The Phosphorus Oxysulfide P4s3o, Zofia Mielke, Lester Andrews, Kiet A. Nguyen, Mark S. Gordon

Mark S. Gordon

Photolysis of the P 4S3--03 molecular complex in solid argon with red light produced two sets of new infrared absorptions including terminal PO and symmetric P-S-P stretching modes, which are assigned to structural isomers of P4S30 with terminal oxygen at the apex and base phosphorus positions of P4S3. Further ultraviolet photolysis produced evidence for oxo-bridged P4S30 and a secondary product, P4S30 2.

73. Professor Cristofor I. Simionescu On His 70th Birthday, Otto Vogl, Ioan I. Negulescu

Otto Vogl

No abstract provided.

Organic And Polymeric Nonlinear Optical Materials, Otto Vogl, Donald R. Ulrich

Otto Vogl

No abstract provided.