Planar integrated wavelength-drop device based on pedestal antiresonant reflecting waveguides and high-Q silica microspheres

Whispering-gallery modes in silica microspheres can be accessed very efficiently with the recently introduced stripline pedestal antiresonant reflecting optical waveguide (SPARROW) structure. This integrated-optics coupling technique creates novel application opportunities for the high-Q spherical cavities. We report the demonstration of a narrow-band wavelength-drop configuration utilizing SPARROW waveguides and a silica microsphere.     

Solidlike transition of melt‐intercalated biodegradable polymer/clay nanocomposites

Synthetic biodegradable aliphatic polyester (BAP) intercalated into organoclay was prepared by melt compounding, and its solidlike characteristics were investigated via several rheological test modes: steady shear rotation, oscillation, and creep testing. Structural investigations with X‐ray diffraction and transmission electron spectroscopy were also performed for a better understanding of the characteristic rheological behaviors. The creep, recovery, and stress modulus exhibited a solidlike transition of BAP/clay nanocomposites that depended on the clay content. An increase in the zero shear rate viscosity and a shifting of the crossover point (storage modulus vs loss modulus) to a lower frequency were also observed with increasing clay contents. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2052–2061, 2003     

Low-pressure ICP-AES with electrothermal vaporizer and a pneumatic nebulizer for aqueous sample introduction.

A typical electrothermal vaporization (ETV) using a tantalum was built for low-pressure ICP-AES. The analytical performance of the ETV was tested and compared with that of a PFA pneumatic nebulizer with a double membrane desolvator (DMD). The limits of detection of the ETV were obtained in the range of 3.4 ng to 758 ng for Zn, Cu, Co, Fe, and Mg, while those of the PFA nebulizer were in the range of 53 ppb to 286 ppb. A relative standard deviation (RSD) of 4.3 - 8.5% for ETV was obtained, while 2.15 - 6.84% RSD was found for DMD.     

Development of a microchip metal ion sensor using dinitro-azocalix[4]azacrown

A microchip metal ion sensor based on absorption of a novel 1,3-alternate calix[4]azacrown having a dinitro-azo-chromophoric pendent group, which was synthesized in this group, was manufactured and its performance was discussed. The microchip optical sensor was composed of light emitting diode (LED, 516.6 nm peak max.) as a light source, photodiode detector, and polydimethyl siloxane (PDMS) microchannel copied from a master of Si wafer. It turns out that dinitro-azocalix[4]azacrown (DAC) can make a complex with various metal ions, such as Na⁺, Ca²⁺, Cu²⁺, and Fe²⁺, based on the fundamental study of spectrochemical properties for optical sensing. The absorption signal was stable and dependent upon concentration of metal ions. Limit of detection for Na⁺ was obtained to be 78.4 ng/mL with relative standard deviation of 2.24%.     

High performance liquid chromatographic studies of erythrocytes haem biosynthetic enzyme activities in alcoholic macrocytosis

The activities of 5-aminolaevulinate dehydrase (ALA-D), hydroxymethylbilane synthase (HMB-S), uroporphyrinogen III synthase (URO-S) and uroporphyrinogen decarboxylase (URO-D) in the erythrocytes of alcoholics were assayed and compared with those in controls and abstaining alcoholics. The HMB-S and URO-S activities in alcoholics were significantly higher than the controls and there were significant correlations between enzyme activities and mean corpuscular volume (MCV). Alcoholics abstaining from alcohol over a nine-month period showed a return to normal enzyme activities in parallel with the normalization of their MCV. Abstaining alcoholics thus all had normal HMB-S and URO-S activities. The ALA-D and URO-D activities of alcoholics were not significantly different from controls or from abstaining alcoholics. Alcohol appears to have a selective effect on the haem biosynthetic enzymes in the erythron.     

A conjecture involving generalized matrix functions

This paper resolves the following conjecture of R. Merris: Let d^G_λ be the generalized matrix function determined by a subgroup G of the symmetric group S_m and an irreducible complex character λ of G. If A, B, and A?B are m-square positive semidefinite hermitian m-square matrices and d^G_λ(A)=d^G_λ(B)≠0, then A=B.     

High‐modulus,high‐strength,thick polypropylene monofilament production: Response surface analysis approach

Response surface analysis was used in optimizing spinning and drawing conditions for the production of a high‐modulus, high‐strength, thick polypropylene (PP) monofilament. Rotatable octagonal central composite design was adopted with two independent variables (take‐up velocity and draw ratio), and variations in the diameter, tensile modulus, and tenacity of the PP monofilament were observed. Quadratic response surface functions described the variations in those properties with quite high correlation coefficients. Canonical analysis combined with contour plots revealed the variation sensitivity: the diameter varied more markedly with the take‐up velocity, and the tensile modulus varied somewhat equally with the two variables, whereas the tenacity varied more markedly with the draw ratio. From such contour plots, the optimum processing conditions for desired properties were predicted without intensive structural analysis. Case studies showed that under the suggested processing conditions, the PP monofilament fulfilled the property requirements, such as a tensile modulus of 10.4 GPa and a tenacity of 672 MPa with a diameter still above 400 μm. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1175–1182, 2003     

Determination of inorganic anions in natural water by microcolumn ion chromatography with on-column enrichment.

An on-column enrichment method was developed for the rapid determination of inorganic anions in natural water. The system was assembled from a syringe pump, a six-port switching valve with a sample-enrichment loop, a separation column and a UV detector. The enrichment efficiency of the system was tested by using inorganic anions as samples. The limits of detection were between 0.6 and 7.7 microg/L. The system was applied to the determination of anions in river and pond-water samples.     

Stochastic quantisation of a gauge field in the spatial axial gauge

The stochastic quantisation method of Nelson can be applied to quantise an Abelian gauge field in the spatial axial gauge.