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3D structure of the lighting activity observed with a VHF interferometer isdescribed. Within large storm observed over Central Florida, we found horizontal stratification of the recoil streamer's channel in the negative part of th...
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3D structure of the lighting activity observed with a VHF interferometer isdescribed. Within large storm observed over Central Florida, we found horizontal stratification of the recoil streamer's channel in the negative part of the cloud (between -2 deg C and -13 deg C). We discuss some aspect of the intra-cloud phenomenology related to storm development.
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The energies of particles are measured in the H1 detector with four different calorimeters. Their designs, which are optimized for their particular requirements, are briefly described. Their performance is characterized in terms o...
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The energies of particles are measured in the H1 detector with four different calorimeters. Their designs, which are optimized for their particular requirements, are briefly described. Their performance is characterized in terms of their operational stability, the precision of their energy scale and their trigger functionality. The most important among the four calorimeters is the large liquid argon calorimeter and therefore most emphasis is given to the description of this component. (orig.)
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The fundamental question on which the chapter focusses involves forest resourceavailability and resource consumption: will the resources from future forests be adequate to meet future needs. The chapter concentrates primarily upon...
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The fundamental question on which the chapter focusses involves forest resourceavailability and resource consumption: will the resources from future forests be adequate to meet future needs. The chapter concentrates primarily upon those for which data is most available, reliable, and measurable: wood, and wood products. All of the conclusions depend upon uncertain climate model simulations (resource availability), uncertainty in adaptive changes in forest product use, and uncertain regional human population growth scenarios (resource consumption).
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Positronium formation (Ps) cross sections for positrons impinging on atomic hydrogen were measured in the impact energy range from 13eV to 255eV at the High Intensity Positron (HIP) beam at Brookhaven National Laboratory (BNL). Th...
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Positronium formation (Ps) cross sections for positrons impinging on atomic hydrogen were measured in the impact energy range from 13eV to 255eV at the High Intensity Positron (HIP) beam at Brookhaven National Laboratory (BNL). The Ps-formation cross section was found to rise rapidly from the threshold at 6.8eV to a maximum value of (2.98 (plus minus) 0.18) (times) 10(sup (minus)16) cm(sup 2) for (approx) 15eV positrons. By 75eV it drops below the detection limit of 0.17 (times) 10(sup (minus)16) cm(sup 2) which is the present level of statistical uncertainty. The experiment was modified to enable the measurement of doubly differential scattering cross sections.
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The recent discovery of the minor isotopomer of ethane, (13)C(12)CH6, in theplanetary atmospheres of Jupiter and Neptune, added ethane to the molecules which can be used to determine isotopic (12)C(12)C ratios for the jovian plane...
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The recent discovery of the minor isotopomer of ethane, (13)C(12)CH6, in theplanetary atmospheres of Jupiter and Neptune, added ethane to the molecules which can be used to determine isotopic (12)C(12)C ratios for the jovian planets. The increased spectral resolution and coverage of the IR and far-IR instruments to be carried on the Cassini mission to Saturn and Titan may enable the detection of the minor isotopomer. Accurate frequency and cross-section measurements of the nu(sub 12) fundamental under controlled laboratory condition are important to interpret current and future planetary spectra. High resolution spectra of the minor isotopomer (13)C(12)CH6 have been recorded in the 12.2 micron region using the Kitt Peak Fourier Transform (FTS) and the Goddard Tunable Diode Laser spectrometer (TDL). In a global fit to 19 molecular constants in a symmetric top Hamiltonian, transition frequencies of the nu(sub 12) fundamental ranging up to J=35 and K=20 have been determined with a standard deviation of less than 0.0005 cm(exp -1). From selected line intensity measurements, a vibrational dipole moment for the nu(sub 12) fundamental has been derived. Observed and calculated spectra covering the region from 740 cm(exp -1) and to 910 cm(exp -1) are presented. A compilation of transition frequencies, line intensities, and lower state energies are included for general use in the astronomical community.
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The development and application of systematic methods for the construction ofsafe software systems is a wide and active area of research in computer science. The thesis presents a meta-calculus, based on a typed lambda-calculus, w...
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The development and application of systematic methods for the construction ofsafe software systems is a wide and active area of research in computer science. The thesis presents a meta-calculus, based on a typed lambda-calculus, which allows the formal description of development methods as well as software developments within these methods. As an integrated description and justification system, the meta-calculus allows to strictly control the correctness of the developments according to the given methods. The thesis contains an informal description and a formal definition of the meta-calculus. Further, it presents basic parts of the language theory of the meta-calculus, strong normalization, and decidability results, as well as a substantial formalization study on a method of equational calculation of programs from specifications. (Copyright (c) 1991 GMD.)
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A high intensity variable energy positron beam has been constructed at Brookhaven National Laboratory (BNL). Positrons from a 97mCi (sup 22)Na source are moderated by a thin layer of solid neon. A magnetic guiding system delivered...
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A high intensity variable energy positron beam has been constructed at Brookhaven National Laboratory (BNL). Positrons from a 97mCi (sup 22)Na source are moderated by a thin layer of solid neon. A magnetic guiding system delivered up to 5(times)10(sup 6)e(sup +)/sec to an experiment. Currently tests are under way to facilitate the operation with the magnetic guiding system or -- for other experimental sites -- with an electrostatic beam transport. The electrostatic lenses are fabricated from (mu)-metal. No compensation of the earth magnetic field is required. Several experiments can utilize the beam on a time sharing basis. In the near future the source will be replaced by (sup 64)Cu which has a much higher activity. Beam intensities up to 10(sup 9)e(sup +)/sec are expected.
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Specular reflection of positronium, Ps was observed and that there is adequate intensity at higher energies to make further study worthwhile was established. The scattering appears to be restricted to the outermost surface with a ...
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Specular reflection of positronium, Ps was observed and that there is adequate intensity at higher energies to make further study worthwhile was established. The scattering appears to be restricted to the outermost surface with a mean free path of (0.75 or - 0.15)A for Ps in LiF(100). With a greater intensity Ps beam one should see higher order diffraction beams as the result of the periodicity of the surface. Ps diffraction thus offers the possibility of being a novel and valuable probe to study the outermost surface and to study adsorbants on it. Two methods for producing Ps beams are described.
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We have observed specular reflection of positronium, Ps, and established that there is adequate intensity at higher energies to make further study worthwhile. The scattering appears to be restricted to the outermost surface with a...
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We have observed specular reflection of positronium, Ps, and established that there is adequate intensity at higher energies to make further study worthwhile. The scattering appears to be restricted to the outermost surface with a mean free path of (0.75 (plus minus) 0.15)(Angstrom) for Ps in LiF(100). With a greater intensity Ps beam one should see higher order diffraction beams as the result of the periodicity of the surface. Ps diffraction thus offers the possibility of being a novel and valuable probe to study the outermost surface and to study adsorbents on it. Two methods for producing Ps beams are described. 29 refs., 11 figs. (ERA citation 15:036250)
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摘要 :
We have observed specular reflection of positronium, Ps, and established that there is adequate intensity at higher energies to make further study worthwhile. The scattering appears to be restricted to the outermost surface with a...
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We have observed specular reflection of positronium, Ps, and established that there is adequate intensity at higher energies to make further study worthwhile. The scattering appears to be restricted to the outermost surface with a mean free path of (0.75 (plus minus) 0.15)(Angstrom) for Ps in LiF(100). With a greater intensity Ps beam one should see higher order diffraction beams as the result of the periodicity of the surface. Ps diffraction thus offers the possibility of being a novel and valuable probe to study the outermost surface and to study adsorbents on it. Two methods for producing Ps beams are described. 29 refs., 11 figs. (ERA citation 15:036250)
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