Measurement of the Proton Structure Function F2F_2 and the Extraction of the Gluon Density at Small xx

In the following article we describe our measurement of the proton structure function $F_2$ and of the gluon momentum density $xg$ in $ep$ collisions with the ZEUS detector at HERA in 1993. The results for $F_2$ confirm our measurement from the previous year but with much higher statistics and show a strong rise towards small $x$. The gluon momentum density $xg$ is measured for the first time in a range from $4 \cdot 10^{-4} < x < 10^{-2}$ at a value of $Q^2 = 20$~GeV$^2$.Comment: 7 pages uuencode-gzipped postscript. LaTeX and individual figures can be found on http://ppewww.ph.gla.ac.uk/preprints/95/01/fleck.shtm

Tungsten wire-reinforced superalloys for 1093 C (2000 F) turbine blade applications

Various combinations of fiber and matrix materials were fabricated and evaluated for the purpose of selecting a specific combination that exhibited the best overall properties for a turbine blade application. A total of seven matrix alloys, including Hastelloy X, Nimonic 80A, Inconel 600, Inconel 625, IN-102, FeCrA1Y, were investigated reinforced with either 218CS tungsten, or W-Hf-C fibers. Based on preliminary screening studies, FeCrA1Y, Inconel 600 and Inconel 625 matrix composites systems were selected for extended thermal cycle tests and for property evaluations which included stress rupture, impact, and oxidation resistance. Of those investigated, the FeCrA1Y matrix composite system exhibited the best overall properties required for a turbine blade application. The W-Hf-C/FeCrA1Y system was selected for further property evaluation. Tensile strength values of up to 724 MPa (105,000 psi) were obtained for this material at 982 C and 607 MPa at 1093 C

Prospective Analysis Spin- and CP-sensitive Variables in H -> ZZ -> l_1 l_1 l_2 l_2 with Atlas

A possibility to prove spin and CP-eigenvalue of a Standard Model (SM) Higgs boson is presented. We exploit angular correlations in the subsequent decay H -> ZZ -> 4l (muons or electrons) for Higgs masses above 200 GeV. We compare the angular distributions of the leptons originating from the SM Higgs with those resulting from decays of hypothetical particles with differing quantum numbers. We restrict our analysis to the use of the Atlas-detector which is one of two multi-purpose detectors at the upcoming 14 TeV proton-proton-collider (LHC) at CERN. By applying a fast simulation of the Atlas detector it can be shown that these correlations will be measured sufficiently well that consistency with the spin-CP hypothesis 0+ of the Standard Model can be verified and the 0- and 1+- can be ruled out with an integrated luminosity of 100 fb^-1.Comment: 25 pages, 9 figures Version 2: Minor changes made as requested by Atlas referee and Springer editor. Added a chapter where background subtraction is detaile

One-dimensional metallic behavior of the stripe phase in La2−x_{2-x}Srx_xCuO4_4

Using an exact diagonalization method within the dynamical mean-field theory we study stripe phases in the two-dimensional Hubbard model. We find a crossover at doping $\delta\simeq 0.05$ from diagonal stripes to vertical site-centered stripes with populated domain walls, stable in a broad range of doping, $0.05<\delta<0.17$. The calculated chemical potential shift $\propto -\delta^2$ and the doping dependence of the magnetic incommensurability are in quantitative agreement with the experimental results for doped La$_{2-x}$Sr$_x$CuO$_4$. The electronic structure shows one-dimensional metallic behavior along the domain walls, and explains the suppression of spectral weight along the Brillouin zone diagonal.Comment: 4 pages, 4 figure

Gehalte an Makro- und Mikroelementen sowie Zuckern in Möhren aus der biologisch-dynamischen und konventionellen landwirtschaftlichen Praxis

Mit dem Ziel, die Marktsituation für den Konsumenten hinsichtlich der Produktqualität zu beschreiben, wurden Proben von Speisemöhren des Anbaujahres 1996 aus der biologisch-dynamischen (n=57) und konventionellen (n=18) Praxis gesammelt. Ermittelt wurden unter Anderem: - Makroelemente: P, K, Na, Cl, Mg, S - Mikroelemente: Fe, B, Zn, Mn, Cu, Pb - Zucker: D-Glu, D-Fru, Sa

Quantum Dot Potentials: Symanzik Scaling, Resurgent Expansions and Quantum Dynamics

This article is concerned with a special class of the ``double-well-like'' potentials that occur naturally in the analysis of finite quantum systems. Special attention is paid, in particular, to the so-called Fokker-Planck potential, which has a particular property: the perturbation series for the ground-state energy vanishes to all orders in the coupling parameter, but the actual ground-state energy is positive and dominated by instanton configurations of the form exp(-a/g), where a is the instanton action. The instanton effects are most naturally taken into account within the modified Bohr-Sommerfeld quantization conditions whose expansion leads to the generalized perturbative expansions (so-called resurgent expansions) for the energy values of the Fokker-Planck potential. Until now, these resurgent expansions have been mainly applied for small values of coupling parameter g, while much less attention has been paid to the strong-coupling regime. In this contribution, we compare the energy values, obtained by directly resumming generalized Bohr-Sommerfeld quantization conditions, to the strong-coupling expansion, for which we determine the first few expansion coefficients in powers of g^(-2/3). Detailed calculations are performed for a wide range of coupling parameters g and indicate a considerable overlap between the regions of validity of the weak-coupling resurgent series and of the strong-coupling expansion. Apart from the analysis of the energy spectrum of the Fokker-Planck Hamiltonian, we also briefly discuss the computation of its eigenfunctions. These eigenfunctions may be utilized for the numerical integration of the (single-particle) time-dependent Schroedinger equation and, hence, for studying the dynamical evolution of the wavepackets in the double-well-like potentials.Comment: 13 pages; RevTe

Spectra of Doubly Heavy Quark Baryons

Baryons containing two heavy quarks are treated in the Born-Oppenheimer approximation. Schr\"odinger equation for two center Coulomb plus harmonic oscillator potential is solved by the method of ethalon equation at large intercenter separations. Asymptotical expansions for energy term and wave function are obtained in the analytical form. Using those formulas, the energy spectra of doubly heavy baryons with various quark compositions are calculated analytically.Comment: 19 pages, latex2e, published at PRC61(2000)04520

Field theoretic description of charge regulation interaction

In order to find the exact form of the electrostatic interaction between two proteins with dissociable charge groups in aqueous solution, we have studied a model system composed of two macroscopic surfaces with charge dissociation sites immersed in a counterion-only ionic solution. Field-theoretic representation of the grand canonical partition function is derived and evaluated within the mean-field approximation, giving the Poisson-Boltzmann theory with the Ninham-Parsegian boundary condition. Gaussian fluctuations around the mean-field are then analyzed in the lowest order correction that we calculate analytically and exactly, using the path integral representation for the partition function of a harmonic oscillator with time-dependent frequency. The first order (one loop) free energy correction gives the interaction free energy that reduces to the zero-frequency van der Waals form in the appropriate limit but in general gives rise to a mono-polar fluctuation term due to charge fluctuation at the dissociation sites. Our formulation opens up the possibility to investigate the Kirkwood-Shumaker interaction in more general contexts where their original derivation fails.Comment: 12 pages, 9 figures, submitted to EPJ

Extended Gaussian wave packet dynamics

We examine an extension to the theory of Gaussian wave packet dynamics in a one-dimensional potential by means of a sequence of time dependent displacement and squeezing transformations. Exact expressions for the quantum dynamics are found, and relationships are explored between the squeezed system, Gaussian wave packet dynamics, the time dependent harmonic oscillator, and wave packet dynamics in a Gauss-Hermite basis. Expressions are given for the matrix elements of the potential in some simple cases. Several examples are given, including the propagation of a non-Gaussian initial state in a Morse potential

Applications of Additive Manufacturing Techniques in Making Energetic Materials

Energetic materials are currently manufactured using methods such as casting, which can only produce certain geometries. Additive manufacturing enables more flexible fabrication and the potential for improved material consistency. Additive manufacturing has transformed many industries, but has only recently been applied to the manufacturing of energetic materials. This paper describes the development of two processes to apply additive manufacturing methods to energetic materials. Method one applies a fused deposition modelling approach (FDM). 5 µm aluminum powder and PVDF were mixed and made into filaments using a Filabot Original filament extruder. Energetic filaments were created composed of 90:10, 80:20, and 75:25 mixtures of PVDF:Al by mass. These filaments had reactive sections, but did not have consistent composition and could not sustain self-propagating reactions. The second method had the goal of mixing ammonium perchlorate (AP) into a curable polymer which solidifies under UV light. Powdered sugar was used in place of AP to simulate the viscosity while testing extrusion and printing capabilities. The powdered sugar and UV Cure mixture could be extruded using a syringe pump when the powdered sugar to UV Cure ratio was 3:1, but this mixture would not stick to the print bed. Both processes need refinement to produce functional energetic materials. This paper forms a foundation for further development of processes in which additive manufacturing can be safely used to produce energetic materials