68,248 research outputs found
Manin-Olshansky triples for Lie superalgebras
Following V. Drinfeld and G. Olshansky, we construct Manin triples (\fg,
\fa, \fa^*) such that \fg is different from Drinfeld's doubles of \fa for
several series of Lie superalgebras \fa which have no even invariant bilinear
form (periplectic, Poisson and contact) and for a remarkable exception.
Straightforward superization of suitable Etingof--Kazhdan's results guarantee
then the uniqueness of -quantization of our Lie bialgebras. Our examples
give solutions to the quantum Yang-Baxter equation in the cases when the
classical YB equation has no solutions. To find explicit solutions is a
separate (open) problem. It is also an open problem to list (\`a la
Belavin-Drinfeld) all solutions of the {\it classical} YB equation for the
Poisson superalgebras \fpo(0|2n) and the exceptional Lie superalgebra
\fk(1|6) which has a Killing-like supersymmetric bilinear form but no Cartan
matrix
Length Dependent Thermal Conductivity Measurements Yield Phonon Mean Free Path Spectra in Nanostructures
Thermal conductivity measurements over variable lengths on nanostructures
such as nanowires provide important information about the mean free paths
(MFPs) of the phonons responsible for heat conduction. However, nearly all of
these measurements have been interpreted using an average MFP even though
phonons in many crystals possess a broad MFP spectrum. Here, we present a
reconstruction method to obtain MFP spectra of nanostructures from
variable-length thermal conductivity measurements. Using this method, we
investigate recently reported length-dependent thermal conductivity
measurements on SiGe alloy nanowires and suspended graphene ribbons. We find
that the recent measurements on graphene imply that 70 % of the heat in
graphene is carried by phonons with MFPs longer than 1 micron
Why has China grown so fast? The role of physical and human capital formation
Cross-province growth regressions for China are estimated for the reform period. Two research questions are asked. Can the regressions help us to understand why China as a whole has grown so fast? What types of investment matter for China's growth? We address the problem of model uncertainty by adopting two approaches to model selection to consider a wide range of candidate predictors of growth. Starting from the baseline equation, the growth impact of physical and human capital is examined using panel data techniques. Both forms of capital promote economic growth. âInvestment in innovationâ and private investment are found to be particularly important. Secondary school enrolment contributes to growth, and higher education enrolment even more so
Sharp sensitivity bounds for mediation under unmeasured mediator-outcome confounding
It is often of interest to decompose a total effect of an exposure into the
component that acts on the outcome through some mediator and the component that
acts independently through other pathways. Said another way, we are interested
in the direct and indirect effects of the exposure on the outcome. Even if the
exposure is randomly assigned, it is often infeasible to randomize the
mediator, leaving the mediator-outcome confounding not fully controlled. We
develop a sensitivity analysis technique that can bound the direct and indirect
effects without parametric assumptions about the unmeasured mediator-outcome
confounding
Pattern Synthesis of Dual-band Shared Aperture Interleaved Linear Antenna Arrays
This paper presents an approach to improve the efficiency of an array aperture by interleaving two different arrays in the same aperture area. Two sub-arrays working at different frequencies are interleaved in the same linear aperture area. The available aperture area is efficiently used. The element positions of antenna array are optimized by using Invasive Weed Optimization (IWO) to reduce the peak side lobe level (PSLL) of the radiation pattern. To overcome the shortness of traditional methods which can only fulfill the design of shared aperture antenna array working at the same frequency, this method can achieve the design of dual-band antenna array with wide working frequency range. Simulation results show that the proposed method is feasible and efficient in the synthesis of dual-band shared aperture antenna array
Weight function for the quantum affine algebra
We give a precise expression for the universal weight function of the quantum
affine algebra . The calculations use the technique of
projecting products of Drinfeld currents on the intersections of Borel
subalgebras.Comment: 28 page
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