High Dynamic-Range and Very Low Noise K-Band p-HEMT LNA MMIC for LMDS and Satellite Communication

An excellent noise figure and high linearity, K-band p-HEMT LNA MMIC, that incorporates single-bias configuration and negative feedback circuit, has be en developed for LMDS (Local Multi-point Distribution Service) and satellite communication. The third order intercept point (IP3) of this MMIC is 20 dBm, while output power at 1-dB gain compression is 8.5 dBm. The IP3 and noise figure is 19.5 +/- 1 dBm and 1.8 +/- 0.2 dB, respectively, at frequencies between 24 and 32 GHz. The die size of the MMIC is 1.9 mm. This MMIC shows a potential reliable application in high-speed wireless access system

Lattice study of meson correlators in the epsilon-regime of two-flavor QCD

We calculate mesonic two-point functions in the epsilon-regime of two-flavor QCD on the lattice with exact chiral symmetry. We use gauge configurations of size 16^3 32 at the lattice spacing a \sim 0.11 fm generated with dynamical overlap fermions. The sea quark mass is fixed at \sim 3 MeV and the valence quark mass is varied in the range 1-4 MeV, both of which are in the epsilon-regime. We find a good consistency with the expectations from the next-to-leading order calculation in the epsilon-expansion of (partially quenched) chiral perturbation theory. From a fit we obtain the pion decay constant F=87.3(5.6) MeV and the chiral condensate Sigma^{MS}=[239.8(4.0) MeV ]^3 up to next-to-next-to-leading order contributions.Comment: 20 pages, 12 figures, final version to appear in PR

Prediction of impeller speed dependence of cavitation intensity in centrifugal pump using cavitating flow simulation with bubble flow model

We developed a numerical method of estimating not only cavitation erosion area but also cavitation intensity that depends on the impeller speed of pumps. Our numerical simulation code with a bubble flow model simulates the bubble pressure and the bubble nuclei distribution in a cavitating flow in detail. We simulated impulsive bubble pressure that varied within microseconds in a centrifugal pump. The cavitation intensity was estimated by analyzing the bubble pressure and the bubble nuclei distribution. The erosion area on the impeller blade in our pump test was visualized by using a method involving dye. The plastic deformation rate of an aluminum sheet attached in the erosion area was measured, and the cavitation intensity was estimated using an experimental database. The erosion area and cavitation intensity were measured at high and low impeller speeds. The erosion areas were both located on the suction side of the impeller blade, and they were distributed between the shroud and the mid-point of the blade near the leading edge. The measured cavitation intensity at high-speed was twice that at low-speed. The predicted areas of high cavitation intensity agreed well with the erosion areas in the experiment though the predicted areas slightly shifted to the leading edge. The predicted cavitation intensity at highspeed doubled that at low-speed as well as the experimental result. Therefore, we confirmed that the numerical method of estimating cavitation intensity was accurate. Next, we added three calculations while changing the impeller speed to obtain a function of cavitation intensity variations. The predicted function was a function of the impeller speed to the power, and this also corresponded to the experimental. Our code is thus effective for estimating the cavitation intensity that increases on the suction side of the impeller blade in a centrifugal pump when the impeller speed is changed.http://deepblue.lib.umich.edu/bitstream/2027.42/84313/1/CAV2009-final15.pd

A20 deficiency sensitizes pancreatic beta cells to cytokine-induced apoptosis in vitro but does not influence type 1 diabetes development in vivo

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Duality for Legendrian contact homology

The main result of this paper is that, off of a `fundamental class' in degree 1, the linearized Legendrian contact homology obeys a version of Poincare duality between homology groups in degrees k and -k. Not only does the result itself simplify calculations, but its proof also establishes a framework for analyzing cohomology operations on the linearized Legendrian contact homology.Comment: This is the version published by Geometry & Topology on 8 December 200

Vanishing cycles and mutation

This is the writeup of a talk given at the European Congress of Mathematics, Barcelona. It considers Picard-Lefschetz theory from the Floer cohomology viewpoint.Comment: 20 pages, LaTeX2e. TeXnical problem should now be fixed, so that the images will appear even if you download the .ps fil

Product structures for Legendrian contact homology

Legendrian contact homology (LCH) is a powerful non-classical invariant of Legendrian knots. Linearization makes the LCH computationally tractable at the expense of discarding nonlinear (and non-commutative) information. To recover some of the nonlinear information while preserving computability, we introduce invariant cup and Massey products – and, more generally, an A∞ structure – on the linearized LCH. We apply the products and A∞ structure in three ways: to find infinite families of Legendrian knots that are not isotopic to their Legendrian mirrors, to reinterpret the duality theorem of the fourth author in terms of the cup product, and to recover higher-order linearizations of the LCH

Finite volume QCD at fixed topological charge

In finite volume the partition function of QCD with a given $\theta$ is a sum of different topological sectors with a weight primarily determined by the topological susceptibility. If a physical observable is evaluated only in a fixed topological sector, the result deviates from the true expectation value by an amount proportional to the inverse space-time volume 1/V. Using the saddle point expansion, we derive formulas to express the correction due to the fixed topological charge in terms of a 1/V expansion. Applying this formula, we propose a class of methods to determine the topological susceptibility in QCD from various correlation functions calculated in a fixed topological sector.Comment: 22pages, references adde