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101.
J. Arnold B. van den Brandt M. Daum M. Finger M. Finger Jr. J. Franz N. Goujon-Naef P. Hautle R. Hess A. Janata J.A. Konter H. Lacker C. Lechanoine-Leluc F. Lehar S. Mango D. Rapin E. Rössle R. Schirmaier P.A. Schmelzbach M. Schmidt H. Schmitt P. Sereni M. Slunecka A. Teglia B. Vuaridel 《The European Physical Journal A - Hadrons and Nuclei》1998,2(4):411-415
Abstact: The kinetic energy spectrum and the polarization of the PSI neutron beam produced in the reaction 12C(p,n)X at 0° with 590 MeV polarized protons were investigated. A strong energy dependence of the neutron beam polarization is
observed which was not expected at the time the neutron beam was built.
Received: 3 April 1998 相似文献
102.
We study the plasma-assisted molecular beam epitaxy of cubic GaN on GaAs(OOl) substrates by means ofin-situ reflection high-energy electron diffraction. The epilayers are characterized by x-ray diffraction, photoluminescence, and
Hall measurements, and it is found that the overall best films are grown under a N/Ga ratio close to one. For anin-situ determination of the N/Ga ratio, the growth kinetics is studied via surface reconstruction transitions. The effective N flux
giving rise to growth is measured using the transient behavior of the half-order diffraction streak intensity for various
plasma operating conditions. 相似文献
103.
Given a function f : ℕ→ℝ, call an n-vertex graph f-connected if separating off k vertices requires the deletion of at least f(k) vertices whenever k≤(n−f(k))/2. This is a common generalization of vertex connectivity (when f is constant) and expansion (when f is linear). We show that an f-connected graph contains a cycle of length linear in n if f is any linear function, contains a 1-factor and a 2-factor if f(k)≥2k+1, and contains a Hamilton cycle if f(k)≥2(k+1)2. We conjecture that linear growth of f suffices to imply hamiltonicity. 相似文献
104.
The bulk etch rate for two types of CR-39 detector was measured as a function of temperature and the activation energies of bulk etching was determined. Experimental values of track etch rate were derived directly from the function of the succesive measured track length vrs. etching time for 209Bi, 129Xe and 20Ne ions.
The maximum etchable length of 13 MeV/u 209Bi and 13.04 MeV/u 129Xe ions have been measured at and below these energies. A comparison of the measured and calculated track length data is presented. 相似文献
105.
M. Zamani M. Fragopoulou S. Stoulos M. Manolopoulou B.A. Kulakov M.I. Krivopustov N.A. Sosnin R. Brandt W. Westmeier M. Debeauvais S.R. Hashemi-Nezhad 《Radiation measurements》2005,40(2-6):410-414
Long-lived isotopes can be transmuted into stable or short-lived elements either by neutron captures or neutron induced fission. The need of a large excess of neutrons has led to the use of accelerator driven sources (ADS). A series of experiments were carried out at the Synchrophasotron/Nuclotron of the Joint Institute for Nuclear Research (JINR) Dubna, using protons of 1.0 GeV. Solid Lead and Uranium targets surrounded by paraffin moderator were irradiated. On the outer surface of the moderator a number of Solid State Track Detectors were placed to monitor neutron spatial distribution. The results showed that the maximum neutron production was reached within the range of one to two proton mean free paths in the target. Then decreasing neutron production follows the proton beam attenuation along the target. Moreover, the results showed both targets neutron production evolution along the target, to be the same. However, neutron flux per incident proton is depended on the target mass, which was found to be higher for the heavier target. 相似文献
106.
Zeitschrift für Physik A Hadrons and nuclei - Es wird an Hand von mikrokinematographischen Aufnahmen das Verhalten eines Aerosols während der Einwirkung intensiver kurzer Schallwellen... 相似文献
107.
Detailed operating characteristics of transversely excited (TE) double-pulse copper bromide lasers employing discharge stabilization techniques are reported. With careful optimization of operating temperature, buffer gas pressure, dissociation and excitation energies, and pulse delay times, specific output energies up to 35μJ/cm3have been obtained for a device of active volume 150 cm3. The nature of the dominant processes influencing ground state and metastable copper atom densities in the interpulse region are discussed in terms of the observed effects of temperature and gas pressure on the characteristic delay times. 相似文献
108.
Andreas Brandt 《Stochastic Processes and their Applications》1988,30(2):253-262
We study the dependence on initial conditions of two recursive filters for cleaning a contaminated time series from additive outliers. We show that the function in the recursive equation is in general not contractive, but nevertheless there exists a stationary solution and two iterates with arbitrary initial conditions coincide after some random time T0. However T0 may be quite large. 相似文献
109.
T. Lund D. Molzahn R. Brandt B. Bergersen D. Eriksen E. Hagebø I.R. Haldorsen T. Bjørnstad C. Richard-Serre 《Physics letters. [Part B]》1981,102(4):239-241
The nuclear interaction between natural copper and 1 GeV 12C has been investigated with radiochemical methods. Charge and mass distributions have been derived. The form of the mass yield curve is determined by the total kinetic energy in the system. 相似文献
110.
Contributions to the Chemistry of Hydrazine and its Derivatives. 53. Synthesis of P-, As-, and Sb-substituted Hydrazines by Addition of P? H, As? H, and Sb? H Groups to N?N Double Bonds Addition of diphenylphosphinous acid, diphenylthiophosphinous acid, methyl hydrogen phenylphosphonite, diethyl hydrogen phosphite, diphenylphosphane, dibutylphosphane, diphenylarsane, diethylarsane, and diphenylstibane to the N?N double bond of diethyl azodicarboxylate, dimethyl azodicarboxylate, ethyl phenylazocarboxylate, and azobenzene yields the P-, As-, and Sb- substituted hydrazines 1–23 . The spectroscopic data agree with the structural formulae. The course of the reactions suggests a polar reaction mechanism except in the case of the synthesis of 15 , which probably proceeds via radical intermediates. The azo systems employed show a distinct graduation in their ability to add to the element-hydrogen groups used. 相似文献