A flexible and high-performance bidirectional optical amplifier with all optical gain control using ASE noise path through multi-port circulators

We report a flexible all-optical gain controlled bidirectional optical amplifier. The device achieves constant gain and low noise figure over a large input power range. Moreover, the device removes Rayleigh backscattered light and amplifier noise.     

Interface study of ion irradiated Cu/Ni/Cu(0 0 2)/Si magnetic thin film by X-ray reflectivity

The irradiation effect of 1 MeV C⁺ on the interface and magnetic anisotropy of epitaxial Cu/Ni system with a perpendicular magnetic anisotropy was investigated by using magneto-optical Kerr effects, grazing incident diffraction and X-ray reflectivity. The magnetic easy-axis was altered from the direction along the surface normal to in-plane and the strain in the Ni layer was relaxed after ion irradiation. Though the interface between the top Cu layer and the Ni layer becomes rough, the contrast of electron densities of Cu and Ni layer increases and the grain-growth occurs during ion irradiation. These phenomena arise from thermo-chemical driving force, i.e. heat of formation, which may be a crucial factor in determining the interface shape in the case of indirect energy transfer mechanism. Therefore, the change of the magnetic anisotropy of the Ni/Cu system after ion irradiation is not due to the formation of the intermixed layer at the interface. The ion irradiation effects on the grain-growth and enhancement of the electronic contrast between Ni and Cu are explained by the interfacial atomic movement caused by thermo-chemical driving force.     

A screening assay for the tetrachlorodibenzo-p-dioxin receptor using the [125I]iodovaleramide derivative of trichlorodibenzo-p-dioxin as the binding ligand

A relatively simple assay method for the putative cytosolic 'receptor' that binds 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds is described. The assay is based on specific binding of [125I]dioxin to cytosol 'receptor' protein. Saturation is ensured by competition experiments in which unlabeled TCDD and other competitors displace the radiolabeled ligand from specific binding sites. This assay has been applied to estimation of levels of 'receptor' in cytosol.     

Remarks on the remaining service time upon reaching a target level in the M/G/1 queue

In this note we establish connections between new and previous results on the remaining service time upon reaching a target level in the M/G/1 queue.     

Non-overlapping control systems on Lie groups

LetG be a Lie group with Lie algebraL(G) and let Ω be a non-empty subset ofL(G). If Ω is interpreted as the set of controls, then the set of elements attainable from the identity for the system Ω is a subsemigroup ofG. A system Ω is called anon-overlapping control system if any element attainable for Ω is only attainable at one time. In this paper, we show that a compact convex generating nonoverlapping control systems on a connected Lie group must be contained inX+E for someX∈L(G)\E, where E is a subspace of codimension one containing the commutator, and the homomorphism from the attainable semigroup intoR ⁺ extends continuously to the whole group in the case of solvable Lie groups. This work is done under the support of TGRC-KOSEF.     

Catalytic synthesis of tricyclic quinoline derivatives from the regioselective hydroamination and C-H bond activation reaction of benzocyclic amines and alkynes

The cationic ruthenium-hydride complex [(PCy3)2(CO)(CH3CN)2RuH]+BF4- (1) was found to be an effective catalyst for the regioselective coupling reaction of benzocyclic amines and terminal alkynes to form the tricyclic quinoline derivatives. The scope of the reaction was explored by using the catalytic system Ru3(CO)12/NH4PF6. The catalytically active cationic ruthenium-acetylide complex [(PCy3)2(CO)(CH3CN)2RuCCPh]+BF4- was isolated from the reaction of 1 with phenylacetylene.     

The association of eotaxin-2 and eotaxin-3 gene polymorphisms in a Korean population with ulcerative colitis

The eotaxin gene family (eotaxin, eotaxin-2 and eotaxin-3) have been implicated in the recruitment of eosinophils, basophiles and helper T (Th) 2 lymphocytes that is a central aspect of allergic disease. We previously suggested that Eo2+179T>C and Eo2 +275C>T of the eotaxin-2, and Eo3 +2497T>G of the eotaxin-3 were significantly associated with susceptibility to asthma. To determine whether the single nucleotide polymorphisms (SNPs) of eotaxin-2 and eotaxin-3 gene family are associated with the susceptibility of ulcerative colitis (UC), we analyzed the genotype of 119 patients with UC and 303 controls using single-base extension (SBE) method. We also calculated the haplotype frequencies among Eo2 +179T>C and Eo2 +275C >T of the eotaxin-2 and Eo3 +2497T>G of the eotaxin-3 in both control and UC patients. The genotype frequency of Eo2 +179T>C and Eo2 +275C>T between UC patients and controls were significantly different (P=0.006 and 0.022, respectively). The genotype and allele frequencies of EoA2497T>G in UC patients were not significantly different from those in the controls without UC patients. Our results suggest that Eo2 +179T>C and Eo2 +275C>T of eotaxin-2 might be associated with the susceptibility of UC.     

Finite time singularities in a 1D model of the quasi-geostrophic equation

In this paper we study 1D equations with nonlocal flux. These models have resemblance of the 2D quasi-geostrophic equation. We show the existence of singularities in finite time and construct explicit solutions to the equations where the singularities formed are shocks. For the critical viscosity case we show formation of singularities and global existence of solutions for small initial data.