1,793 research outputs found
Impact of tubificid worms on ecosystem in ricefield with organic farming (Biological Interactions in Arable Land-Grassland-Forest Continuums and their Impact on the Ecosystem Functions, 7th International Symposium on Integrated Field Science)
Electrochemical reaction engineering of polymer electrolyte fuel cell
Although fuel cells can be considered as a type of reactor, methods of kinetic analysis and reactor modeling from the viewpoint of chemical reaction engineering have not yet been established. The rate of an electrochemical reaction is a function of concentration, temperature, and interfacial potential difference (or electromotive force). This study examined the cathode reaction in a polymer electrolyte fuel cell, in which oxygen and protons react over platinum in the catalyst layer (CL). The effects of the oxygen partial pressure and the cathode electromotive force on the reaction rate were assessed. Resistance to proton transport increases the electromotive force and reducing the reaction rate. It was established that the effectiveness factor of the cathode CL is determined by competition between the reaction and mass transport of oxygen and protons. Two dimensionless moduli that govern the cathode behavior are proposed as a means of depicting the processes in the cell
Excitation of Giant Monopole Resonance in Pb and Sn Using Inelastic Deuteron Scattering
The excitation of the isoscalar giant monopole resonance (ISGMR) in
Sn and Pb has been investigated using small-angle (including
) inelastic scattering of 100 MeV/u deuteron and
multipole-decomposition analysis (MDA). The extracted strength distributions
agree well with those from inelastic scattering of 100 MeV/u
particles. These measurements establish deuteron inelastic scattering at E 100 MeV/u as a suitable probe for extraction of the ISGMR strength with
MDA, making feasible the investigation of this resonance in radioactive
isotopes in inverse kinematics.Comment: 5 pages, 4 figures. To be published in Phys. Lett.
Uncomputably noisy ergodic limits
V'yugin has shown that there are a computable shift-invariant measure on
Cantor space and a simple function f such that there is no computable bound on
the rate of convergence of the ergodic averages A_n f. Here it is shown that in
fact one can construct an example with the property that there is no computable
bound on the complexity of the limit; that is, there is no computable bound on
how complex a simple function needs to be to approximate the limit to within a
given epsilon
Replication factor encoded by a putative oncogene, set, associated with myeloid leukemogenesis.
Isotopic dependence of the giant monopole resonance in the even-A ^{112-124}Sn isotopes and the asymmetry term in nuclear incompressibility
The strength distributions of the giant monopole resonance (GMR) have been
measured in the even-A Sn isotopes (A=112--124) with inelastic scattering of
400-MeV particles in the angular range
--. We find that the experimentally-observed GMR energies
of the Sn isotopes are lower than the values predicted by theoretical
calculations that reproduce the GMR energies in Pb and Zr very
well. From the GMR data, a value of MeV is obtained
for the asymmetry-term in the nuclear incompressibility.Comment: Submitted to Physical Review Letters. 10 pages; 4 figure
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