Sol–Gel Synthesis of Cadmium Telluride-Microcrystal-Doped Silica Glasses

The sol–gel process has been applied to the preparation of small-sized CdTe-doped silica glasses. Gels synthesized by the hydrolysis of a complex solution of Si(OC₂H₅)₄, Cd(CH₃COO)₂· 2H₂O, and Te were heated from 350° to 600°C in a H₂─N₂ atmosphere to form fine cubic CdTe crystals. The size of CdTe crystals, determined from the line broadening of X-ray diffraction pattern, increases from 4 to 9 nm in diameter with increasing heat-treatment temperature. The optical absorption edge shifts to the higher-energy side as the size of the CdTe crystals decreases. This phenomenon is interpreted in terms of a quantum confinement effect of electron and hole in the CdTe microcrystals.     

Novel positive deep UV resist for KrF excimer laser lithography

A novel positive deep UV resist for KrF excimer laser lithography has been developed. The resist is composed of 1,7-bis(4-chlorosulfonyl phenyl)-4-diazo-3,5-heptanedione as the alkaline dissolution inhibitor and an alkali-soluble sytrene polymer as the main-polymer. 1,7-bis(4-chlorosulfonyl phenyl)-4-diazo-3,5-heptanedione has great capability of alkaline dissolution inhibition. High thermal stability and excellent photobleachability at 248 nm of the compound are also characterized. The alkali-soluble styrene polymer has a high transmittance of 70% in 1.0 μm thickness at 248 nm. The novel positive resist had an excellent property for dissolution kinetics and photobleaching. We achieved high aspect ratio half-micron pattern fabrication in 1.0 μm thickness using the new resist.     

Reconfiguration of Logical Topologies with Minimum Traffic Disruptions in Reliable WDM-Based Mesh Networks

A wavelength division multiplexing (WDM) network offers a flexible networking infrastructure by assigning the route and wavelength of lightpaths. We can construct an optimal logical topology, by properly setting up the lightpaths. Furthermore, setting up a backup lightpath for each lightpath improves network reliability. When traffic demand changes, a new optimal (or sub-optimal) topology should be obtained by again applying the formulation. Then, we can reconfigure the running topology to the logical topology obtained. However, during this reconfiguration, traffic loss may occur due to the deletion of older lightpaths. In this paper, we consider reconfiguring the logical topology in reliable WDM-based mesh networks, and we propose five procedures that can be used to reconfigure a running lightpath to a new one. Applying the procedures one by one produces a new logical topology. The procedures mainly focus on utilizing free wavelength resources and the resources of backup lightpaths, which are not used usually for transporting traffic. The results of computer simulations indicate that the traffic loss is remarkably reduced in the 14-node network we used as an example.     

玻璃钢薄板圆柱的抗扭阻尼特性

当一个复合材料用于结构件时其阻尼特性是非常重要的。这样的复合材料也比金属具有较好的阻尼特性。例如，机器人手臂的精确运动和汽车上推进器轴的无声运转都与抗扭阻尼特性密切相关。     

Radiation effect on the thermal conductivity and diffusivity of ramie fibers in a range of low temperatures by γ rays

To understand the influence on the thermal conductivity by the length of the molecular chain in the polymer fiber, the thermal conductivity and thermal diffusivity of ramie fibers and those irradiated by γ rays, which induced molecular chain scission of cellulose, were investigated in a range of low temperatures. The degrees of polymerization, crystallinities, and orientation angles of ramie fibers and those irradiated by γ rays (γ‐ray treatment) were measured by the solution viscosity method, solid‐state NMR, and X‐ray diffraction. Only the degree of polymerization decreased with the γ‐ray treatment, and the crystallinities and orientation angles were almost independent of the γ‐ray treatment. The thermal conductivities of the ramie fibers with and without γ‐ray treatments decreased with decreasing temperature. The thermal diffusivities of the ramie fibers and those irradiated by γ rays were almost constant from 250 to 100 K, increased slightly with the temperature decreasing from 100 to 50 K, and increased rapidly with the temperature decreasing below 50 K. The thermal conductivity and thermal diffusivity of the ramie fibers decreased with the γ‐ray treatment. The mean free path of the phonon in the ramie fibers was reduced by the γ‐ray treatment. This decrease of the thermal diffusivity and thermal conductivity was explained by the reduction of the mean free path of the phonon by molecular chain scission with γ rays. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 5007–5018, 2006     

Construction of Chemical Potential Diagrams for Metal-Metal-Nonmetal Systems: Applications to the Decomposition of Double Oxides

A chemical potential diagram for A-B-O (A, B = metallic elements) systems has been constructed to make visually clear the thermodynamic stability of double oxides; the stability area of metallic elements, their binary oxides, and double oxides can be presented as convex polygons in a log ( a _A/ a _B) vs log P (O₂) plot, a and P (O₂) being the activity of metallic elements and the oxygen partial pressure, respectively; the axis variable, log ( a _A/ a _B), is used to treat two metallic elements equivalently. The Co-Ti-O and La-Co-O systems have been chosen as examples to demonstrate how the present diagram can provide complicated phase relations in a compact and visualized manner. An attempt has also been made to utilize this diagram to present graphically products of kinetic decomposition of double oxides placed in an oxygen potential gradient.     

Chemical sensing by analysing dynamics of plasma polymer film-coated sensors

A chemical sensing system that incorporates unique sensor films and uses pattern recgonition of their dynamic responses is presented. This system consists of a sensor array of quartz-crystal microbalances coated with plasma polymer films. The films, synthesized by radio-frequency sputtering, are useful because of their high density of radical sites and unsaturated bonds. When this sensor array is exposed to a gas, the adsorption and desorption of the target gas causes a dynamic frequency response in each piezoelectric sensor. The sensor response is analysed by an autoregressive model typically to estimate the parameters of dynamic systems. This model's coefficients reflect the sensor dynamics, providing pattern vectors that characterize the target gas. Based on this model, classification maps for single gases can be created with these pattern vectors. Thesse maps show that the dynamic sensor response provides useful information for gas classification. This model also confirms that our sensing system can identify the components of a gas mixture.