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11.
Deuteron production cross sections are calculated from an intranuclear cascade model for Ne + U and Ar + Ca at 400 MeV/A. In effect, there are no adjustable parameters in this calculation. The parameters of the cascade code are fixed by sum charged inclusive data. Furthermore, the high momentum deuteron inclusive distribution is found to be insensitive to the details of the deuteron wave function. This latter observation leads to a justification of a generalized coalescence formula involving both momentum and spatial coordinates. Satisfactory agreement is found between our calculations and both the untriggered and high multiplicity triggered inclusive spectra of deuterons with energies ?50 MeV/A. 相似文献
12.
Frankel BA Bentley M Kruger RG McCafferty DG 《Journal of the American Chemical Society》2004,126(11):3404-3405
Several small molecule vinyl sulfones were found to exhibit irreversible time-dependent inhibition of the Staphylococcus aureus sortase SrtA in vitro. A representative of these compounds was shown to impair the ability of S. aureus bacteria to bind fibronectin-coated surfaces through in vivo inhibition of SrtA-mediated linkage of fibronectin to the cell surface. These data highlight the potential use of small molecule vinyl sulfones as chemotherapeutics to prevent adhesion to and colonization of host tissues during S. aureus infection. 相似文献
13.
ABSTRACT. Let G be the group ?[t, t ?1] x ?. By studying the action of the braid group Bn on the set Gn , we obtain representations of Bn into a wreath product of the symmetric group and the general linear group over ?[t, t ?1]. This in particular recovers the Burau representation of the braid group. Furthermore, some quotients of the braid group are obtained by using the representations found. 相似文献
14.
V ? R,T deactivation of the ν4 (243 cm?1) level in BCl3 by HCl has been measured over the range 220–340 K, with an infrared double resonance technique. The deactivation probabilities show an inverse temperature dependence below room temperature, indicating that long-range attractive forces are important in the resonant transfer process. The results are compared with the theory of Sharma and Brau. 相似文献
15.
Jay I. Frankel Majid Keyhani Rao V. Arimilli Jayne Wu 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2008,57(2):869-888
This paper derives a new integral relationship between heat flux and temperature in a transient, two-dimensional heat conducting
half space. A unified mathematical treatment is proposed that is extendable to higher-dimensional and finite-region geometries.
The analytic expression provides the local heat flux perpendicular to the front surface solely based on an embedded line of
temperature sensors parallel to the surface. The relationship does not require apriori knowledge of the surface boundary condition.
A new sensor strategy is analytically conceived based on the integral relationship for estimating the local, in-depth heat
flux without surface instrumentation. It should further be clarified that the integral relationship requires only knowledge
of the local, in-depth temperature and heating/cooling rate (time rate of change of temperature). The resulting formulation
is mildly ill-posed and either requires digital filtering of the temperature signal to remove high frequency components of
noise or the development of direct heating/cooling rate sensors. This paper (a) develops the new mathematical relationship;
(b) demonstrates that the proposed relationship reduces to well-known (i) one-dimensional results under the appropriate assumptions;
and, (ii) two-dimensional surface results; and, (c) provides a simple numerical example validating the concept. 相似文献
16.
17.
J. I. Frankel 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1996,47(3):456-466
A new formulation possessing stable numerical characteristics is presented for inverse Stefan design processes. In such processes, the goal of the analysis is to design transient boundary conditions which produce the desired interfacial surface motion. This subclass of mildly ill-posed mathematical problems is amenable to the proposed solution methodology. This investigation presents a fixed-front differential formulation from which a weighted residual statement is developed. Orthogonal collocation is used to obtain numerical results illustrating the merit of imposing physical constraints in the mathematical model. These mathematical constraints can be viewed as design specifications and are available to the designer or experimentalist. The proposed methodology is flexible and can be generalized to problems involving continuous casting or crystal growth. Finally, symbolic manipulation is used for augmenting the computational methodology. 相似文献
18.
H. A. Maia F. F. T. De Araújo M. A. B. De Araújo J. Danon R. B. Frankel 《Hyperfine Interactions》1993,77(1):43-50
Mössbauer spectra of jacobsite have been recorded at temperatures of 4.2, 125, 180, 240 and 300 K and with an external magnetic field of 60 kOe applied parallel to the incident radiation at 4.2 K. The results show the presence of two different magnetic hyperfine interactions associated with the iron nuclei. Spectra of samples in external magnetic fields indicate the same sign for the magnetic hyperfine interactions, implying that both iron ions occupy only the octahedral sublattice. These results are compared with data from synthetic stoichiometry manganese ferrite, and a model of cation distribution, assuming the existence of vacancies, is proposed. According to this model, the mineral jacobsite is rich in manganese compared with stoichiometric MnFe2O4 ferrite. 相似文献
19.
Summary A conventional push-rod dilatometer is modified in order to accurately correlate the measured density to the predicted sample
temperature of alloys in the phase-change regime. This new configuration makes use of a standard furnace assembly; however,
the specimen is now symmetrically encased in a well-instrumented, graphite cylindrical shell. The combination of system geometry
and high-conductivity sample holder material promotes the development of a simplified heat transfer model. The solution of
this model properly correlates the measured density to that of the actual sample temperature based on using remote, sample-holder
temperature measurements. Preliminary results using aluminum A356 provide insight into the proposed configuration. 相似文献
20.
We study a two-phase Stefan problem with kinetics. Here we prove existence of a finite-dimensional attractor for the problem
without heat losses. Fot the most part we use a more elegant technique of energetic type estimates in appropriately defined
weighted Sobolev spaces as opposite to the parabolic potentials of [9]. We demonstrate existence of compact attractors in
the Sobolev spaces and prove that the attractor consists of sufficiently regular functions. This allows us to show that the
Hausdorff dimension of the attractor is finite. 相似文献