2,302 research outputs found
Control of nonlinear singularly perturbed systems using gain scheduling
No full textIn this paper we analyze an asymptotic stability of nonlinear singularly perturbed systems and propose a composite control with gain scheduling where the fast controller is the gain scheduled controller and the slow state plays a role of slowly varying parameters in gain scheduling. Specifically, the slow controller is designed by the slow manifold to stabilize the reduced slow system. As a result, the slow manifold of the system is the same as the designed manifold
Fluorescence excitation spectrum of OClO ((A)over-tilde(2)A(2))
No full textThe fluorescence excitation (FE) spectrum for the (A) over tilde A(2) <-> (X) over tilde(2)B(1) transition of OClO cooled in supersonic jet expansions has been obtained for the first time from the origin band at 476 nm up to 355 nm. Despite rapid predissociation of the excited OC10 molecules, the fluorescence emission is strong enough to give the FE spectrum with a high signal-to-noise ratio. The present FE spectrum shows the much lower rotational temperature and hence better state resolution than seen in previously reported spectra, demonstrating that it can be used as a convenient spectroscopic tool for the state and mode selection in the photodissociation dynamics studies. The FE spectroscopy can be also applied for the high-resolution spectroscopy and various kinetic studies on the OClO molecules.Korean Science and Engineering Foundation
Inha University Research Fun
Pitting corrosion of the laser surface melted Alloy 600
No full textThe effect of laser surface melting (LSM) on the resistance to pitting corrosion of Ni-base Alloy 600 was investigated by a potentiodynamic polarization test in 1 M NaCl solutions at pH values of 4 and 10 at temperatures of 30, 60 and 90degreesC. The pitting potentials of Alloy 600 were markedly increased by the LSM process, when compared with those of the non-laser treated Alloy 600. From the microscopic examination after the corrosion test, it was found that the pitting was initiated at the junction between a TiN inclusion and the matrix, possibly at the site of a sulfide physically associated with the TiN inclusion. The homogeneous micro-structure associated with the reduction of the inclusion size during the LSM process could be attributed to the improvement of the pitting corrosion properties in the LSM alloy 600. (C) 2004 Elsevier B.V. All rights reserved.This work has been carried out as a part of the Nuclear
R&D Program by M.O.S.T. in Korea
(Poster) Quantitative analysis of carrier escape and recombination efficiency in GaN-based blue light-emitting diodes
No full textEffects of sensitization treatment on the evolution of Cr carbides in rapidly solidified Ni-base alloy 600 by a CO2 laser beam
No full textThe effects of heat treatment on the precipitation of Cr carbides in Ni-base Alloy 600 laser surface melted by a CO2 laser beam were investigated with microscopic equipment. Aging treatment at 600 degrees C for 24 h induced precipitation of Cr-rich M23C6 and Cr7C3 carbides on some high angle grain boundaries, and the minimum Cr concentration along the grain boundary was measured to be about 12 wt%. In particular, the Cr-rich M23C6 was precipitated on TiN and MgS type particles surrounded by tangled dislocations along the cell boundaries in the laser melted zone. The precipitation behaviors of Cr carbides in the laser surface melted and subsequently sensitized Alloy 600 were analyzed and then compared with those of the conventionally processed, solution annealed and then identically sensitized Alloy 600 from the viewpoint of different microstructural features. (C) 2000 Elsevier Science S.A. All rights reserved
The strain relaxation in a lattice-mismatched heterostructure
No full textStrain relaxation phenomena of the heteroepitaxial lattice-mismatched semiconductors have been investigated. The relationship between the residual in-plane strain and the width of the misfit cell was obtained geometrically. The residual in-plane strain was calculated for various film thicknesses by using the energy minimization theory on the misfit cell in the InxGa1-xAs/GaAs(1 0 0) heterostructure system. A generalized strain relaxation model is presented on the basis of the energy minimization theory. (C) 1999 Elsevier Science B.V. All rights reserved
Particle formation in the rapidly solidified zone of alloy 600 surface melted by a CO2 laser beam
No full textUnexpectedly large O37ClO/O35ClO intensity ratios of the fluorescence from the low-energy vibrational levels of OClO (Ã 2A2)
No full textThe fluorescence intensity ratios of (OClO)-Cl-37/(OClO)-Cl-35 excited to the (A) over tilde (2)A(2) state have been found to be much larger than that expected from the Cl-37/Cl-35 natural abundance ratio for several low-energy vibrational levels. For instance, the (OClO)-Cl-37/(OClO)-Cl-35 ratios are 1.67 and >10 for the (0,0,0) and (1,1,0) bands, respectively, which are 5 and 30 times larger than those expected from the natural abundance ratio. These unusual isotope effects are observed in a narrow energy region within similar to 1000 cm(-1) above the electronic origin. It is likely that the isotopomer-selective, near-resonant spin-orbit coupling of the low-energy vibrational levels of the (2)A(2) state with those of the (2)A(1) state, which provides a decay channel for the (2)A(2) state via spin-orbit coupling, is responsible for the unusual isotope effect. (C) 1999 American Institute of Physics. [S0021-9606(99)02126-1].Korean Science and Engineering Foundation
Inha University Research Fun
Association between RASSF1A methylation and clinicopathological factors in patients with squamous cell carcinoma of lung
No full textBackground: RASSF1A, which is one of tumor suppressor genes, is frequently inactivated by hypermethylation of the promoter region in a variety of human cancers, including lung cancer. This study was performed to investigate the association between RASSF1A methylation and the clinicopathological factors in patients with squamous cell carcinoma of the lung. Methods: Eighty-one samples from the patients with squamous cell carcinoma of lung were examined. The promoter methyation of RASSF1A was analyzed by methylation specific PCR and sequencing. Statistical analysis was made to examine the association between RASSF1A methylation and the clinicopathological parameters. Results: RASSF1A methylation was observed in 37.0% (30 of 81) of the patients with squamous cell carcinoma of the lung. RASSF1A methylation was found to be associated with cellular differentiation(p=0.0097) and the overall survival(p=0.0835). However, there was no association between RASSF1A methylation and the other clinicopathological parameters, such as the pathological TNM stage, the recurrence rate, lymph node invasion and the amount of cigarettes smoked. Conclusion: RASSF1A methylation might be associated with a poor prognosis in patients with squamous carcinoma of the lung. A larger scale study is needed
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