Randomly-grown high-dielectric-constant ZnO nanorods for?near-field enhanced Raman scattering

We investigate the dependence of the size parameter in the Mie scattering theory on the near-field enhanced Raman scattering properties for high dielectric constant ZnO nanorods grown randomly by PLD (pulsed laser deposition). High Raman signals of Rhodamine 6G (R6G) at 532 nm excitation wavelength were observed with nanorods of 400 nm average diameter. This experimental result was explained theoretically by the size parameter described in the Mie scattering theory, not by surface plasmon polaritons. This was also confirmed by the near-field distribution calculated by the FDTD (Finite-Difference Time Domain) method. The ZnO nanorods with 400 nm average diameter can detect as low as 1 μM of R6G. This near-field enhancement factor is equivalent to that with 10-nm-thick gold-coated ZnO nanorods (nanoshells) with an average core diameter of 100 nm. Controlling the diameter of bare ZnO nanorods is effective for obtaining large enhancement factors without an additional process of gold thin film coating on them.     

Wurster’s Blue‐type Cation Radicals Framed in a 5,10‐Dihydrobenzo[a]indolo[2,3‐c]carbazole (BIC) Skeleton: Dual Electrochromism with Drastic Changes in UV/Vis/NIR and Fluorescence

Electron‐donating dihydrobenzindolocarbazoles (BICs) 1 a – c , which adopt planar disk‐shaped geometries, were prepared by gold(I)‐catalyzed cyclization as a key step. Due to the presence of a 1,4‐phenylenediamine (PD) moiety in the framework, they undergo reversible one‐electron oxidation to the corresponding Wurster’s Blue (WB)‐type species that exhibits NIR absorptions up to λ=1200 nm. In the case of the N,N′‐dimethyl derivative, cation radical 1 c ^+. is stable enough to be isolated as a salt and X‐ray analysis indicated paraquinoid‐type bond alternation in the WB core unit, whereas the bond lengths in the peripheral benzene rings are identical to those in the neutral donor. Upon electrochemical interconversion, the redox pairs of 1 a – c and 1 a – c ^+. exhibited an electrochromic response in the UV/Vis/NIR region, which was accompanied by a drastic change in the fluorescence spectrum because only neutral donors 1 a – c are highly emissive (Φ_F: 0.7–0.8).     

Free-flow electrophoresis in a microfabricated chamber with a micromodule fraction separator. Continuous separation of proteins

Continuous free flow electrophoresis of proteins was carried out in a microfabricated free flow electrophoresis (mFFE) module with the 30-μm thick slit of the separation. The newly developed micromodule fraction separator (MFS) was attached to the down-stream end site of the separation chamber of mFFE. By using the MFS, electrolyte solution from the separation chamber was introduced to the peristaltic pump without disturbing the electrolyte solution flow at the bottom side of the chamber. The separation of protein mixture samples was achieved by a hydroxypropylmethylcellulose pretreatment coating of the separation chamber. The pretreatment of the sample chamber effectively suppressed electroosmotic flow. All fractionated samples were collected using the MFS after continuous elecrophoresis and analyzed by reversed-phase HPLC. From the results of HPLC analyses none of the cytochrome c fractions at the other ports revealed cross talk phenomena at adjacent ports. A similar result occurred for the myoglobin. This means that these proteins were completely separated from each other by continuous mFFE, and the MFS functioned efficiently during continuous electrophoresis.     

Ion-Free latex films as dual-phase electrolytes: Styrene–butadiene rubber and nitrile–butadiene rubber synthesized by emulsion polymerization with poly-(vinyl pyrrolidone) stabilizer

Ion-free latices of styrene-butadiene rubber (SBR) and nitrile-butadiene rubber (NBR) were synthesized by emulsion polymerization with use of poly (vinyl pyrrolidone) (PVP) stabilizer. The goal was to prepare ion-free latex films, possessing dual-phase latex particle morphology, and swell the films with liquid electrolyte to yield dual-phase polymer electrolytes (DPE). SBR/PVP latex was prepared readily, but NBR/PVP latex was sensitive to coagulation. Differential scanning calorimetric (DSC) and scanning electron microscopic (SEM) analyses of latex films provided morphological evidence concerning particle structure and phase separation. Blends of NBR/PVP and PB/PVP latices (PB = polybutadiene) were also investigated, but particle structure was not present in the blended latex film, even though particle structure was present in the individual NBR/PVP and PB/PVP latex films. After extensive swelling of SBR/PVP latex films, PVP was extracted from the films, and ionic conductivities greater than 10^?3 S/cm were achieved. © 1994-John Wiley & Sons, Inc.     

A Robust Point Spread Function Estimation for Out-of-Focus Blurred and Noisy Images Based on a Distribution of Gradient Vectors on the Polar Plane

The estimation of the point spread function (PSF) is a very important and indispensable task for practical image restoration. Various PSF estimation algorithms have been developed, especially for the out-of-focus blur. However, a majority of them are useless in an extremely noisy environment. This paper describes a new robust PSF estimation algorithm based on a distribution of gradient vectors on the logarithmic amplitude spectrum mapped to the polar plane. The proposed algorithm can estimate the out-of-focus PSF accurately and robustly, even for an image highly corrupted by noise. The effectiveness of the proposed algorithm is verified by applying it to the PSF estimation for out-of-focus blurred and noisy images.     

Large-dispersion-tolerance optical signal transmission system based on temporal imaging

A novel optical signal transmission system, which is highly tolerant of dispersion of the transmission fiber, is proposed. The system employs a dispersion fiber and a phase modulator in both the transmitter and the receiver. We analyzed the characteristics of the system, using the temporal imaging concept, and found that the output optical pulse is insensitive to dispersion of the transmission fiber if the parameters of the system are set to hold a specific condition. We report simulation results that confirm these characteristics of the proposed system.     

Local tunneling barrier height observations of NiAl(1 1 0)

Local work functions at individual atoms on a compound metal surface have been experimentally examined. The simultaneously obtained STM and local tunneling barrier height (LBH) images of NiAl(1 1 0) show that LBH at geometrically lower Ni sites is much higher than that at geometrically higher Al sites, indicating that each individual atom on the NiAl(1 1 0) surface has a specific potential barrier for relevant electrons.