189,758 research outputs found
Investigation of split injection in a single cylinder optical diesel engine
SAE paper 2010-01-0605, Copyright © 2010 SAE International. This paper is posted on this site with permission from SAE International, and is for viewing only. Further use and distribution of this paper is not permitted without permission from SAE.Over the last decade, the diesel engine has made dramatic progress in its performance and market penetration. However, in order to meet future emissions legislations, Nitrogen Oxides (NOx) and particulate matters’ (PM) emissions will need to be reduced simultaneously. Nowadays researchers are focused on different combustion modes which can have a great potential for both low soot and low NOx. In order to achieve this, different injection strategies have been investigated.
This study investigates the effects of split injection strategies with high levels of Exhaust Gas Recirculation (EGR) on combustion performance and emissions in a single cylinder direct injection optical diesel engine. The investigation is focused on the effects of injection timing of split injection strategies.
A Ricardo Hydra single cylinder optical engine was used in which conventional experimental methods like cylinder pressure data, heat release analysis and exhaust emissions analysis were applied. Optical techniques like direct spray and combustion visualization were applied by means of a high speed imaging system with a copper vapor laser illumination system and a high-speed two-color system was applied to obtain in-cylinder diesel combustion temperature and soot measurements distributions
Nonequilibrium spin-transfer torque in SFNFS junctions
We report theoretical results for the nonequilibrium spin current and
spin-transfer torque in voltage-biased SFNFS Josephson structures. The
subharmonic gap structures and high voltage asymptotic behaviors of the dc and
ac components of the spin current are analyzed and related to the
spin-dependent inelastic scattering of quasiparticles at both F layers.Comment: minor changes, published versio
Evidence for very strong electron-phonon coupling in YBa_{2}Cu_{3}O_{6}
From the observed oxygen-isotope shift of the mid-infrared two-magnon
absorption peak of YBaCuO, we evaluate the oxygen-isotope
effect on the in-plane antiferromagnetic exchange energy . The exchange
energy in YBaCuO is found to decrease by about 0.9% upon
replacing O by O, which is slightly larger than that (0.6%) in
LaCuO. From the oxygen-isotope effects, we determine the lower
limit of the polaron binding energy, which is about 1.7 eV for
YBaCuO and 1.5 eV for LaCuO, in quantitative
agreement with angle-resolved photoemission data, optical conductivity data,
and the parameter-free theoretical estimate. The large polaron binding energies
in the insulating parent compounds suggest that electron-phonon coupling should
also be strong in doped superconducting cuprates and may play an essential role
in high-temperature superconductivity.Comment: 4 pages, 1 figur
A Generalization of Mathieu Subspaces to Modules of Associative Algebras
We first propose a generalization of the notion of Mathieu subspaces of
associative algebras , which was introduced recently in [Z4] and
[Z6], to -modules . The newly introduced notion in a
certain sense also generalizes the notion of submodules. Related with this new
notion, we also introduce the sets and of stable elements
and quasi-stable elements, respectively, for all -subspaces of -modules , where is the base ring of . We then
prove some general properties of the sets and .
Furthermore, examples from certain modules of the quasi-stable algebras [Z6],
matrix algebras over fields and polynomial algebras are also studied.Comment: A new case has been added; some mistakes and misprints have been
corrected. Latex, 31 page
Relative FP-injective and FP-flat complexes and their model structures
In this paper, we introduce the notions of -injective and -flat complexes in terms of complexes of type . We show that
some characterizations analogous to that of injective, FP-injective and flat
complexes exist for -injective and -flat complexes. We
also introduce and study -injective and -flat
dimensions of modules and complexes, and give a relation between them in terms
of Pontrjagin duality. The existence of pre-envelopes and covers in this
setting is discussed, and we prove that any complex has an -flat
cover and an -flat pre-envelope, and in the case that
any complex has an -injective cover and an -injective
pre-envelope. Finally, we construct model structures on the category of
complexes from the classes of modules with bounded -injective and
-flat dimensions, and analyze several conditions under which it is
possible to connect these model structures via Quillen functors and Quillen
equivalences.Comment: 41 page
Towards understanding the probability of ground states in even-even many-body systems
For single- shells with and 11/2, we relate the large
probability of ground states to the largest (smallest) coefficients
, where is the particle number, is the seniority, is an
additional quantum number, and is the angular momentum of the state.
Interesting regularities of the probabilities of ground states are
noticed and discussed for 4-particle systems. Several counter examples of the
ground state (0GS) predominance are noticed for the first time.Comment: 5 pages, 1 figure. Phys. Rev. C64, in pres
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