12,281 research outputs found

    Fuel optimum stochastic attitude control

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    Numerical solution of stochastic Hamilton-Jacobi equation for fuel optimal spacecraft attitude control syste

    Generalized Feedback Shift Register Pseudorandom Number Algorithm

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    The generalized feedback shift register pseudorandom number algorithm has several advantages over all other pseudorandom number generators. These advantages are: (1) it produces multidimensional pseudorandom numbers; (2) it has an arbitrarily long period independent of the word size of the computer on which it is implemented; (3) it is faster than other pseudorandom number generators; (4) the same floating-point pseudorandom number sequence is obtained on any machine, that is, the high order mantissa bits of each pseudorandom number agree on all machines— examples are given for IBM 360, Sperry-Rand-Univac 1108, Control Data 6000, and Hewlett-Packard 2100 series computers; (5) it can be coded in compiler languages (it is portable); (6) the algorithm is easily implemented in microcode and has been programmed for an Interdata computer. © 1973, ACM. All rights reserved

    The 1980 US/Canada wheat and barley exploratory experiment. Volume 2: Addenda

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    Three study areas supporting the U.S./Canada Wheat and Barley Exploratory Experiment are discussed including an evaluation of the experiment shakedown test analyst labeling results, an evaluation of the crop proportion estimate procedure 1A component, and the evaluation of spring wheat and barley crop calendar models for the 1979 crop year

    Absolute rate of the reaction of hydrogen atoms with ozone from 219-360 K

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    Absolute rate constants for the reaction of atomic hydrogen with ozone were obtained over the temperature range 219-360 K by the flash photolysis-resonance fluorescence technique. The results can be expressed in Arrhenius form by K = (1.33 plus or minus 0.32)x10 to the minus 10 power exp (-449 plus or minus 58/T) cu cm/molecule/s (two standard deviations). The present work is compared to two previous determinations and is discussed theoretically

    Absolute rate of the reaction of bromine atoms with ozone from 200-360 K

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    The rate constant for the reaction Br + O3 yields BrO + O2 was measured from 200 to 360 K by the technique of flash photolysis coupled to time resolved detection of bromine atoms by resonance fluorescence (FP-RF). Br atoms were produced by the flash photolysis of CH3Br at lambda 165nm.O3 was monitored continuously under reaction conditions by absorption at 253.7 nm. At each of five temperatures the results were independent of substantial variations in O3, total pressure and limited variations in flash intensity. The measured rate constants obeyed the Arrhenius expression, where the error quoted is two standard deviations. Results are compared with previous determinations which employed the discharge flow-mass spectrometric technique

    Application of wavelets to singular integral scattering equations

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    The use of orthonormal wavelet basis functions for solving singular integral scattering equations is investigated. It is shown that these basis functions lead to sparse matrix equations which can be solved by iterative techniques. The scaling properties of wavelets are used to derive an efficient method for evaluating the singular integrals. The accuracy and efficiency of the wavelet transforms is demonstrated by solving the two-body T-matrix equation without partial wave projection. The resulting matrix equation which is characteristic of multiparticle integral scattering equations is found to provide an efficient method for obtaining accurate approximate solutions to the integral equation. These results indicate that wavelet transforms may provide a useful tool for studying few-body systems.Comment: 11 pages, 4 figure

    Thermal Diffusivities of Functionalized Pentacene Semiconductors

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    We have measured the interlayer and in-plane (needle axis) thermal diffusivities of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn). The needle axis value is comparable to the phonon thermal conductivities of quasi-one dimensional organic metals with excellent pi-orbital overlap, and its value suggests that a significant fraction of heat is carried by optical phonons. Furthermore, the interlayer (c-axis) thermal diffusivity is at least an order of magnitude larger, and this unusual anisotropy implies very strong dispersion of optical modes in the interlayer direction, presumably due to interactions between the silyl-containing side groups. Similar values for both in-plane and interlayer diffusivities have been observed for several other functionalized pentacene semiconductors with related structures.Comment: 9 pages, including 4 figures; submitted to Applied Physics Letter

    Absolute rate of the reaction of Cl(p-2) with molecular hydrogen from 200 - 500 K

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    Rate constants for the reaction of atomic chlorine with hydrogen are measured from 200 - 500 K using the flash photolysis-resonance fluorescence technique. The results are compared with previous work and are discussed with particular reference to the equilibrium constant for the reaction and to relative rate data for chlorine atom reactions. Theoretical calculations, using the BEBO method with tunneling, give excellent agreement with experiment

    Absolute rate of the reaction of C l(2P) with methane from 200-500 K

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    Rate constants for the reaction of atomic chlorine with methane have been measured from 200-500K using the flash photolysis-resonance fluorescence technique. When the results from fourteen equally spaced experimental determinations are plotted in Arrhenius form a definite curvature is noted. The results are compared to previous work and are theoretically discussed

    Finite Projective Spaces, Geometric Spreads of Lines and Multi-Qubits

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    Given a (2N - 1)-dimensional projective space over GF(2), PG(2N - 1, 2), and its geometric spread of lines, there exists a remarkable mapping of this space onto PG(N - 1, 4) where the lines of the spread correspond to the points and subspaces spanned by pairs of lines to the lines of PG(N - 1, 4). Under such mapping, a non-degenerate quadric surface of the former space has for its image a non-singular Hermitian variety in the latter space, this quadric being {\it hyperbolic} or {\it elliptic} in dependence on N being {\it even} or {\it odd}, respectively. We employ this property to show that generalized Pauli groups of N-qubits also form two distinct families according to the parity of N and to put the role of symmetric operators into a new perspective. The N=4 case is taken to illustrate the issue.Comment: 3 pages, no figures/tables; V2 - short introductory paragraph added; V3 - to appear in Int. J. Mod. Phys.
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