4,573 research outputs found

    Distribution Functions From Breit-Frame Regularisation

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    We suggest a new Hamiltonian lattice approach, using a regularisation motivated by deep inelastic scattering. We discuss the relation between distribution functions and the F1F_1 structure function. We have tested this method by computing the critical behaviour of the scalar model and find agreement with scaling behaviour and with results by L\"uscher and Weisz.Comment: 3 pages. Talk presented at LATTICE96(phenomenology

    Computation of Structure Functions From a Lattice Hamiltonian

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    We compute structure functions in the Hamiltonian formalism on a momentum lattice using a physically motivated regularisation that links the maximal parton number to the lattice size. We show for the ϕ3+14\phi ^4 _{3+1} theory that our method allows to describe continuum physics. The critical line and the renormalised mass spectrum close to the critical line are computed and scaling behaviour is observed in good agreement with L{\"u}scher and Weisz' lattice results. We then compute distribution functions and find a Q2Q^2 behaviour and the typical peak at xB0x_B\rightarrow 0 like in QCDQCD.Comment: 4 pages, three figures. Submitted to Phys.Rev.Let

    Template-free inorganic synthesis of silica-based nanotubes and their self-assembly to mesocrystals

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    A novel synthesis approach for silica-based nanotubes (NTs) was discovered in the purely inorganic system containing the molecular compounds OP(NH2)3, SP(NH2)3 and SiCl4 in evacuated and sealed silica glass ampoules. Without any solvent or structure directing template the amorphous NTs self-organise to form orthogonally ordered, 3D hyperbranched mesocrystals, exhibiting an interesting material for nanofluidic device applications

    Public Land Use Constraints: Lot and House Configuration

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    The public sector constrains the size and shape of lots and buildings via zoning ordinances and subdivision regulations. Zoning ordinances utilize setback requirements, open space ratios, minimum lot area and floor-to-area ratios. Subdivision regulations utilize street and sidewalk spacing requirements. This article provides a framework in which one can analyze the precise impact of these control devices. The choice of developers who face these controls is discussed in terms of a rule of thumb and in terms of a model of profit maximization.

    The Massive Schwinger Model in a Fast Moving Frame

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    We present a non-perturbative study of the massive Schwinger model. We use a Hamiltonian approach, based on a momentum lattice corresponding to a fast moving reference frame, and equal time quantization.Comment: contribution to Lattice'98 including: 2 style files (espcrc2.sty,psfig.sty) + text file (LaTeX) + 3 figures (ps) + complete paper(ps

    Influence of Yttrium on the Thermal Stability of Ti-Al-N Thin Films

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    Ti(1-x)Al(x)N coated tools are commonly used in high-speed machining, where the cutting edge of an end-mill or insert is exposed to temperatures up to 1100 degrees C. Here, we investigate the effect of Yttrium addition on the thermal stability of Ti(1-x)Al(x)N coatings. Reactive DC magnetron sputtering of powder metallurgically prepared Ti(0.50)Al(0.50), Ti(0.49)Al(0.49)Y(0.02), and Ti(0.46)Al(0.46)Y(0.08) targets result in the formation of single-phase cubic (c) Ti(0.45)Al(0.55)N, binary cubic/wurtzite c/w-Ti(0.41)Al(0.57)Y(0.02)N and singe-phase w-Ti(0.38)Al(0.54)Y(0.08)N coatings. Using pulsed DC reactive magnetron sputtering for the Ti(0.49)Al(0.49)Y(0.02) target allows preparing single-phase c-Ti(0.46)Al(0.52)Y(0.02)N coatings. By employing thermal analyses in combination with X-ray diffraction and transmission electron microscopy investigations of as deposited and annealed (in He atmosphere) samples, we revealed that Y effectively retards the decomposition of the Ti(1-x-y)Al(x)Y(y)N solid-solution to higher temperatures and promotes the precipitation of c-TiN, c-YN, and w-AlN. Due to their different microstructure and morphology already in the as deposited state, the hardness of the coatings decreases from similar to 35 to 22 GPa with increasing Y-content and increasing wurtzite phase fraction. Highest peak hardness of similar to 38 GPa is obtained for the Y-free c-Ti(0.45)Al(0.55)N coating after annealing at T(a) = 950 degrees C, due to spinodal decomposition. After annealing above 1000 degrees C the highest hardness is obtained for the 2 mol % YN containing c-Ti(0.46)Al(0.52)Y(0.02)N coating with similar to 29 and 28 GPa for T(a) = 1150 and 1200 degrees C, respectively

    Pulsatile velocity of blood in the pulmonary artery of dogs: measurement by an ultrasound gauge

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    An advanced model of an ultrasound flow gauge, mounted on a N7 catheter was used to measure flow velocity in the pulmonary artery of closed-chest dogs. The recorded flow signals were calibrated in cm/sec by determining stroke volume (by dye dilution) and diameter of the pulmonary artery (by angiography). The influence of positive and negative inotropic drugs on velocity and acceleration is reporte
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