Fractional Wiener filter

The fractional correlation is a new operation that can easily be implemented by optical means. This operation might be useful for shift-variant pattern recognition and for image restoration. The Wiener filter is the optimal filter according to the minimal square-error criterion. For a given spectral noise that distorts the reference image, this filter is optimal for restoring an image in noise. A fractional Wiener filter is suggested for restoring reference objects in a fractional correlation system. The new filter sometimes performs better than the conventional Wiener filter.     

A new approach to the design of high-Tc superconductors: Metallised interlayers

We show from muon spin relaxation (SR) studies on mercury HTS superconductors that a 50-fold increase in irreversibility field obtained by partial substitution of Re for Hg is due to metallisation of the Hg/Re layer. Induced superconductivity on this metallic layer doubles the overall superfluid density. This suggests a new approach to the design of high performance HTS materials: metallising one of the non-CuO₂ interlayers and thereby greatly enhancing the superconducting properties.     

A Glucose Biosensor Based on Immobilization of Glucose Oxidase in Electropolymerized o-Aminophenol Film on Platinized Glassy Carbon Electrode

A high-performance amperometric glucose biosensor has been developed, based on immobilization of glucose oxidase in an electrochemically synthesized, nonconducting poly(o-aminophenol) film on a platinized glassy carbon electrode. The large microscopic surface area and porous morphology of the platinized glassy carbon electrode result in high enzyme loading, and the enzyme entrapped in the electrodeposited platinum microparticle matrix is stabler than that on a platinum disk electrode surface. The response current of the sensor is 20-fold higher than that of the sensor prepared with a platinum disk electrode of the same geometric area. The experiments showed that the high sensitivity of the sensor is due not only to the large microscopic area but also to the high efficiency of transformation of H(2)O(2) generated by enzymatic reaction to current signal on the platinized glassy carbon electrode. The response time of the sensor is <4 s, and its lifetime is >10 months.     

Design and fabrication of a diffractive phase element for wavelength demultiplexing and spatial focusing simultaneously

The design of a diffractive phase element (DPE) that simultaneously implements wavelength demultiplexing and focusing is carried out on the basis of the general theory of amplitude-phase retrieval. The designed DPE is fabricated with optical contact lithography. Three masks are needed to produce the surface-relief structure of the DPE with eight quantized levels in depths. Experiments demonstrate that the designed DPE can successfully implement both the functions of demultiplexing three different-wavelength beams and focusing each component at a predesignated position simultaneously. Experimental measurements are in good agreement with the results of numerical simulations.     

Three-map absolute moiré contouring

In the shadow-moiré system, the period of the grating is varied by rotation of the grating, so the phase of the moiré pattern is changed as well. By the selection of suitable rotation angles, three images at different positions of the grating are acquired to obtain the absolute distance from the object to the grating. A theoretical analysis is presented for the method, and some experiments have been done to verify the theoretical analysis. The results show that the method is fast and the accuracy is better than 10 μm. The measurable range is directly proportional to the period of the grating and inversely proportional to the angles at which the grating is rotated.     

A clinical nude mouse metastatic model for highly malignant human pancreatic cancer

Pancreatic cancer is a highly aggressive and treatment-refractory cancer. A clinically-relevant animal model is necessary to develop therapy for metastatic pancreatic cancer. In this study we evaluated the efficacy of mitomycin C (MMC) and 5-FU against the human pancreatic adenocarcinoma cell line PAN-12 in an orthotopic human metastatic pancreatic cancer nude mice model. The model is constructed by surgical orthotopic implantation (SOI) of histologically intact tumor tissue in the tail portion of the pancreas near the spleen. PAN-12 grew very aggressively in the control group of nude mice with extensive local invasion and distant metastasis to various organs with a propensity for the lung but to other organs as well, including the liver, kidney and regional and distant lymph nodes. In a striking effect none of the mice in the MMC-treated group developed tumor. Although mice in the 5-FU treated group survived statistically significantly longer than those in the untreated control, the overall incidence of metastasis in these mice was equivalent to those in the control. However no liver or kidney metastases were found in the 5-FU treated animals perhaps accounting in part for their longer survival. This "clinical" nude mouse model of highly metastatic pancreatic cancer can now be used to discover new effective agents for this disease.     

Experimental and theoretical studies of the crossover behavior of the specific heat Cv,x of ethane,propane, and their mixture at critical isochores

The specific heat at constant volume, C_v, of propane, and mixture with a concentration ofx=0.0081 cool fraction of propane was measured along the critical isochores at temperatures between 290 and 400 K. The measurements were performed with a high-temperature constant-volume adiabatic calorimeter. The uncertainty of most of the measurements is estimated to be less than 1.5%. Measurements have been carried out in both the one- and two-phase regions. The results for the pure components are compared with earlier measurements. Crossover equations forC, obtained on the basis of the renormalization-group method and -expansion are applied to represent our experimental specific heat data for ethane, propane. and its mixture along the critical isochores.     

Planar optical waveguide with PbCl2 cladding: a chlorine sensor

Single-mode optical waveguides of 1 mm width are fabricated by thermal indiffusion so that Na⁺ is replaced by K⁺ in a simple soda-lime glass substrate. PbCl₂ is selectively vacuum evaporated on to the waveguide surface as a sensitive layer (cladding). The thickness of the cladding is varied from 170 nm to 480 nm, with clad length from 2 mm to 6 mm. The prism-film coupling method with an He-Ne laser ( = 632.8 nm) is used for characterization. The output light intensity of a TM-mode is detected by a silicon photovoltaic detector. The waveguides are tested for different gases (O₂, H₂, CO₂, N₂, Cl₂, H₂O), in an airtight glass chamber. The presence of only Cl₂ in the surrounding air ambient reduces the output, even at a few p.p.m.. The Cl₂ gas concentration is varied from 3 p.p.m. to 1.5%.There are slight changes in sensitivity with variation in the cladding thickness and length. A drastic change in sensitivity for different concentration ranges is observed as three distinct regions. The response time over a few p.p.m. to hundreds of p.p.m. is around 5 s and beyond 500 p.p.m. is around 2 s.