Noninvasive subsurface analysis using multiple miniaturized Raman probes, part I: basic study of thin-layered transparent models of biomedical tissues

This study describes a basic theory for reconstructing pure Raman signals of materials composing a multilayer sample from Raman spectra obtained using two types of miniaturized Raman probes. An illustrative example is demonstrated using a multilayer system of samples composed of the transparent plastics polymethylmethacrylate (PMMA) and polyethylene (PE) as a model of thin-layered biomedical tissues. When the same region of an object is measured using Raman probes with different focal properties, the Raman spectra provide different depth profile information depending on the level of light penetration. Thus, a detailed comparison of the spectra can provide an interesting opportunity to probe the differences between the layers. A simple analytic form is presented for reconstructing the pure Raman spectra of the embedded layer. The method applies an understanding of the Raman sampling volume in layered transparent materials to the interpretation of Raman spectra experimentally measured by multiple probes. The basic theory described here is necessary for the expansion of the technique to turbid media, such as biological samples, where light-scattering effects must be considered. The potential applications of the proposed method include material and catalyst subsurface probing through different embedded materials, such as assessment of silicon wafers, effective noninvasive screening for catalyst synthesis, and biomedical tissue research.     

Improved visible-light responsive photocatalytic activity of N and Si co-doped titanias

Thermal reaction of titanium tetraisopropoxide and tetraethyl orthosilicate in 1,4-butanediol afforded nanocrystalline silica-modified titanias having large surface area and superior thermal stability. In this study, the thus-obtained silica-modified titanias were treated in an NH₃ flow at high temperatures, and their physical and photocatalytic properties were investigated. Compared with NH₃-treated TiO₂ without silica modification, the NH₃-treated silica-modified titanias showed a stronger absorption in the visible region (400–500 nm) and had a larger peak at 396 eV in the N 1s XPS spectrum. These results indicate that a larger amount of nitrogen was stably doped in the silica-modified titania. The obtained products exhibited a high photocatalytic activity for degradation of Rhodamine B and decomposition of acetaldehyde under visible light irradiation. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Thin-Film Thermoelectric Modules for Power Generation Using Focused Solar Light

We demonstrated the fabrication of thin-film thermoelectric generators and evaluated their generation properties using solar light as a thermal source. Thin-film elements of Bi_0.5Sb_1.5Te₃ (p-type) and Bi₂Te_2.7Se_0.3 (n-type), which were patterned using the lift-off technique, were deposited on glass substrates using radiofrequency magnetron sputtering. After annealing at 300°C, the average Seebeck coefficients of p- and n-type films were 150???V/K and ?104???V/K, respectively, at 50°C to 75°C. A cylindrical lens was used to focus solar light to a line shape onto the hot side of the thin-film thermoelectric module with 15 p?Cn junctions. The minimum width of line-shaped solar light was 0.8?mm with solar concentration of 12.5 suns. We studied the properties of thermoelectric modules with different-sized p?Cn junctions on the hot side, and obtained maximum open voltage and power values of 140?mV and 0.7???W, respectively, for a module with 0.5-mm p?Cn junctions. The conversion efficiency was 8.75?×?10^?4%, which was approximately equal to the value estimated by the finite-element method.     

Evaluation of transistor property variations within chips on 300-mm wafers using a new MOSFET array test structure

A new test structure has been designed to evaluate fluctuations of transistor properties, both within a chip and across a 300-mm wafer. The evaluation system was established with a conventional parametric tester and dc power supplies suitable for application on production lines. It was observed that threshold voltage (V/sub th/) variations increased with the reduction of the channel area. A difference was also observed in the standard deviation (/spl sigma//sub vt/) between NMOS and PMOS. From statistical evaluations, controlling CDs and improving rolloff characteristics were found to be important to reduce V/sub th/ variations.     

Optical and electrical anisotropies of polydiacetylene derivative film aligned by shear stress

The molecular alignment of polydiacetylene (PDA) derivatives and their optical and electrical properties of thin films based on PDA derivatives have been studied. The PDA derivatives were aligned depending on the direction of applied shear stress in the film. From measurements of the polarized absorption and current–voltage characteristics, the optical and electrical anisotropies have been observed, that was discussed by taking the PDA main chain alignment into consideration.     

Application of gamma ray computed tomography to non-destructive testing

A gamma ray computed tomography (ψ-ray CT) system has been developed for applications to large specimens of high density materials.The system features a wide fan beam of ψ-rays, extendable up to 20 degrees, 20 channel ψ-ray scintillation detectors using bismuth germanate oxide with a counting rate being up to 10⁵ per second for reducing the mechanical scan time. Performance of the ψ-ray CT system is confirmed by measuring a test piece and a stepping motor (diameter: 5 cm; main material component: iron), for instance. It can represent these cross-sectional images with a spatial resolution of 1.5 mm. About 10 min are required to obtain these images using a 100 mCi ¹³⁷Cs source.     

Periodic, fully developed, natural convection in a channel with corrugated confining walls

Numerical solutions are obtained for natural convection heat transfer in an open channel with corrugated, isothermal confining walls. The channel is very long so that the fluid temperature approaches the wall temperature and the flow can be assumed to be periodically fully developed. The solutions are obtained by solving the full elliptic governing equations in a transformed coordinate system which maps the channel with corrugated walls onto a channel with flat walls. The periodic, fully developed Nusselt number for the corrugated channel is expressed by the relation Nu = CGrPr/(L/W) where Gr, Pr and L/W are the Grashof number, the Prandtl number and the aspect ratio, respectively, and C is a parameter which is a function of Gr, L/W and the corrugation angle θ. In the limiting case of θ = 0° (two flat walls), the parameter C approaches a constant value. This value is within 1.6% of the exact analytical result.     

Kernel analysis of partial least squares (PLS) regression models

An analytical technique based on kernel matrix representation is demonstrated to provide further chemically meaningful insight into partial least squares (PLS) regression models. The kernel matrix condenses essential information about scores derived from PLS or principal component analysis (PCA). Thus, it becomes possible to establish the proper interpretation of the scores. A PLS model for the total nitrogen (TN) content in multiple Thai fish sauces is built with a set of near-infrared (NIR) transmittance spectra of the fish sauce samples. The kernel analysis of the scores effectively reveals that the variation of the spectral feature induced by the change in protein content is substantially associated with the total water content and the protein hydration. Kernel analysis is also carried out on a set of time-dependent infrared (IR) spectra representing transient evaporation of ethanol from a binary mixture solution of ethanol and oleic acid. A PLS model to predict the elapsed time is built with the IR spectra and the kernel matrix is derived from the scores. The detailed analysis of the kernel matrix provides penetrating insight into the interaction between the ethanol and the oleic acid.     

折叠之舞

这所住宅位于日本古老的首都--京都中心传统住宅街区内,由建筑师Kentaro Takeguchi+Asako Yamamoto/ALPHAVILLE共同设计建造。由于地区性建筑规范和邻里关系的制约,住宅外部延续了日本传统木制别墅的特征,尽量低调谦和地融入外部传统街区环境之中。当夜暮降临,透过住宅临街的木质格栅散透出柔和的暖光,晕染着这个