Infrared-laser delivery system based on polymer-coated hollow fibers

Infrared Er : YAG laser delivery systems based on hollow fibers with an internal polymer layer has been developed. The system consists of a hollow fiber as the delivery medium, a launching coupler for effective coupling between the laser beam and the fiber, and a sealed hollow-fiber tip attached at the output end of the fiber. Fabrication process of the fiber and attachment of the delivery system is reported.     

Effect of fuel injection location on a plasma jet assisted combustion with a backward-facing step

Non-reacting and reacting experiments on the ignition by a plasma jet (PJ) torch were performed to understand the correlation between fuel injection location and combustion characteristics in unheated Mach 2 airflow. Fuel was injected through three sonic injectors in the recirculation region behind a backward-facing step: a parallel injector at 2 mm from the bottom wall and two normal injectors at 2 and 9 mm from the step wall. In order to mitigate the combustion pressure interaction with nozzle, an isolator was installed between the nozzle and combustor. The combustion performance of normal injection was little affected by the difference of fuel injection locations. Moreover, normally injected fuel was escaped not to be held in the recirculation region despite of low fuel injection rates. This led to lower combustion performance relative to the parallel injection which provided fuel not to leave the recirculation region. In this case, the role of the recirculation region was to fully hold fuel, and the PJ torch provided hot gases as a heat source and acted as a flame-holder to ignite fuel–air mixtures. In a low temperature inflow condition, combustible regions were constrained around the bottom wall where embedded with the PJ torch. When thermal choking occurred in the combustor, it induced shock train both in the combustor and isolator. Under this unstable condition, the combustion performance of the normal injection was lower than that of the parallel injection. This is because the normal injection led most fuel into low temperature incoming air-stream.     

Synthesis and stereochemistry-activity relationship of small bacteriocin, an autoinducer of the symbiotic nitrogen-fixing bacterium Rhizobium leguminosarum

The four stereoisomers of small bacteriocin, an autoinducer of the symbiotic nitrogen-fixing bacterium Rhizobium leguminosarum, were synthesized via a versatile methodology for 3'-hydroxyacyl homoserine lactones based on the Nagao asymmetric aldol reaction. The synthetic isomers were much less effective at inhibiting the growth of R. leguminosarum RBL5523 than the natural isomer, showing the importance of stereochemistry for activity.     

Characteristics of coherent transverse optical phonon in CuI thin films on Au nano-films

We have investigated the coherent phonon in CuI thin films deposited on Au films with nanoscale roughness. It is found that the coherent transverse optical (TO) phonon in the CuI thin film on the Au film is dramatically enhanced, whereas that in the CuI thin film without the Au film is hardly observed. The enhancement of the coherent TO phonon in the CuI thin film on the Au film will originate from the surface enhanced electric field around the surface of the Au film with nanoscale roughness. To clarify the properties of the enhanced coherent phonon, we have investigated the pump-power dependence and pump-polarization dependence of the coherent phonon. We discuss the generation process of the coherent phonon in the CuI thin film on the Au film as compared with the pump-power dependence and the pump-polarization dependence.     

Boundary operators in the one-matrix model

The one matrix model is known to reproduce in the continuum limit the (2,2p+1)$(2,2p+1)$ minimal Liouville gravity. Recently, two of the authors have shown how to construct arbitrary critical boundary conditions within this matrix model. So far, between two such boundary conditions only one boundary operator was constructed. In this Letter, we explain how to construct all the set of boundary operators that can be inserted. As a consistency check, we reproduce the corresponding Liouville boundary 2pt function from the matrix model correlator. In addition, we remark a connection between a matrix model relation and the boundary ground ring operator insertion in the continuum theory.     

Discovery of deep and shallow trap states from step structures of rutile TiO2 vicinal surfaces by second harmonic and sum frequency generation spectroscopy

In this report, local electronic structures of steps and terraces on rutile TiO(2) single crystal faces were studied by second harmonic and sum frequency generation (SHG∕SFG) spectroscopy. We attained selective measurement of the local electronic states of the step bunches formed on the vicinal (17 18 1) and (15 13 0) surfaces using a recently developed step-selective probing technique. The electronic structures of the flat (110)-(1×1) (the terrace face of the vicinal surfaces) and (011)-(2×1) surfaces were also discussed. The SHG∕SFG spectra showed that step structures are mainly responsible for the formation of trap states, since significant resonances from the trap states were observed only from the vicinal surfaces. We detected deep hole trap (DHT) states and shallow electron trap (SET) states selectively from the step bunches on the vicinal surfaces. Detailed analysis of the SHG∕SFG spectra showed that the DHT and SET states are more likely to be induced at the top edges of the step bunches than on their hillsides. Unlike the SET states, the DHT states were observed only at the step bunches parallel to [1?1?1] [equivalent to the step bunches formed on the (17 18 1) surface]. Photocatalytic activity for each TiO(2) sample was also measured through methylene blue photodegradation reactions and was found to follow the sequence: (110) < (17 18 1) < (15 13 0) < (011), indicating that steps along [0?0?1] are more reactive than steps along [1?1?1]. This result implies that the presence of the DHT states observed from the step bunches parallel to [1?1?1] did not effectively contribute to the methylene blue photodegradation reactions.     

Reversible solid-state structural conversion between a three-dimensional network and a one-dimensional chain of Cu(II) triazole coordination polymers in acidic/basic-suspensions or vapors

New Cu(II) triazole coordination polymers with a 3D network were synthesized and reversible structural conversion between a 3D network and a 1D chain with color change was realized by pH controlled acidic and basic-suspensions or vapors. For each conversion process of decreasing and increasing pH, conversion was accomplished with high yield, in which the crystal before conversion played the role of a solid-state crystal template.     

Eisenstein series and zeta functions on symplectic groups

Oblatum 22-III-1994 & 6-VI-1994