Observation of iron silicide formation by plan-view transmission electron microscopy

The formation and the phase transitions of iron silicide by solid-phase epitaxy have been investigated by means of plan-view transmission electron microscopy, which enables us to observe a clean interface between Fe and Si. Layers of Fe were deposited on Si (100) at room temperature in an ultrahigh vacuum chamber. The sample was annealed in the electron microscope at a temperature between 673 and 1073 K. After annealing at 673 K, FeSi crystallites were formed with various orientations. When the annealing temperature was increased to 973 K, we found that the crystallites suddenly started to coalesce into grains of several hundreds of nanometers in size and polycrystalline beta-FeSi2 was formed. These phase transitions were also confirmed with electron energy-loss spectroscopy.     

Characterization of infrared and near-infrared absorptions of free alcoholic OH groups in hydrocarbon

We have demonstrated that the near-infrared and infrared absorptions in the 8000-3200 cm(-1) region of an OH group of 2-nonanol, 1-nonanol, etc., in n-heptane are excellently separated by subtraction without any serious interference down to very low concentrations at which OH groups are completely free. The separated sharp absorptions are assigned to the fundamental, combination, and overtone bands that are concerned with the OH stretching of free OH. Two components of a sharp overtone band around 7100 cm(-1), which are observed for primary and secondary alcohols, are assigned to coexisting internal rotational isomers of an OH group around the O-C bond. The frequencies of the OH stretching fundamental and overtone bands that are assigned to internal rotational positions are consistent for all the investigated alcohols, including methanol and tertiary butanol. Comparison of the separated spectrum of 2-nonanol in n-heptane with that in 1-chlorooctane or in carbon tetrachloride makes it clear that hydrocarbon is an inert solvent that does not disturb the intrinsic nature of an alcohol OH group. There actually exists a constant anharmonicity shift of 169-175 cm(-1) between the double frequency (2nu(OH)o) of the observed fundamental and the observed overtone frequency ([2nu(OH)]o) for free OH of various alcohols in n-heptane.     

A general steady state mathematical model for fin-and-tube heat exchanger based on graph theory

Fin-and-tube heat exchangers are widely used in air conditioners, chillers, etc. A lot of factors, including arrangement of refrigerant circuits, configure specification of fins and tubes, and operating conditions, have significant influence on the performance of fin-and-tube heat exchangers. For the purpose of fast design of high performance heat exchangers, a simulator reflecting the influence of these factors is necessary. In this paper, a general steady state mathematic model based on the graph theory is presented. With the help of the directed graph and graph-based traversal methods (Breadth-first search and Depth-first search), this model is capable to describe any flexible refrigerant circuit arrangement, and quantify the refrigerant distribution in the refrigerant circuit and heat conduction through fins. An alternative iteration method is also developed to solve the conservation equations, which can shorten the simulating time effectively. The model is verified with the experimental results, and the maximum error is within ±10.0%. A simulator based on this model has been used for designing practical fin-and-tube heat exchangers.     

Fabrication of low-loss and wide-bandwidth v.a.d. optical fibres at 1.3 ?m wavelength

A low-loss and wide-bandwidth optical fibre in the long-wavelength region has been fabricated by the v.a.d. method. Loss at 1.3 ?m is 0.98 dB/km and 6 dB down bandwidth is 1600 MHz km at 1.26 ?m.     

Fuzzy conditional inference under max-⊙ composition

This paper shows that the majority of fuzzy inference methods for a fuzzy conditional proposition “If x is A then y is B,” with A and B fuzzy concepts, can infer very reasonable consequences which fit our intuition with respect to several criteria such as modus ponens and modus tollens, if a new composition called “max-⊙ composition” is used in the compositional rule of inference, though reasonable consequences cannot always be obtained when using the max-min composition, which is used usually in the compositional rule of inference. Furthermore, it is shown that a syllogism holds for the majority of the methods under the max-⊙ composition, though they do not always satisfy the syllogism under the max-min composition.     

Induction of TNF-alpha production from human peripheral blood monocytes with beta-1,3-glucan oligomer prepared from laminarin with beta-1,3-glucanase from Bacillus clausii NM-1

We prepared a beta-1,3-glucan oligomer (DP> or = 4) from laminarin (DP: 25-30) derived from Laminaria digitata with beta-1,3-glucanase, and examined its effect on human peripheral blood monocytes. Conditioned medium prepared by incubating monocytes (MC-CM) with the beta-1,3-glucan oligomer showed strong inhibitory activity against the proliferation of human leukemic U937 cells. Since the beta-1,3-glucan oligomer had no direct cytotoxic effect on U937 cells up to 1000 microg/ml, the cytotoxicity of the MC-CM may be due to cytotoxic cytokines produced from monocytes stimulated by the beta-1,3-glucan oligomer. On the other hand, the MC-CM prepared with original laminarin had little effect on the growth of U937 cells. The cytotoxicity of the MC-CM prepared with the beta-1,3-glucan oligomer was significantly reduced by an anti-TNF-alpha antibody, but the anti-TNF-beta antibody had no effect. Our results suggest that the enzymatically depolymerized beta-1,3-glucan oligomer induces TNF-alpha production from human monocytes.     

Dietary CLA and DHA modify skin properties in mice

This study investigated the influence of PUFA on the properties of mouse skin. Mice (3 wk old) were given free access to oils high in linoleic acid, CLA, or DHA for 4 wk. At the end of the experiment, their skins were compared by both biochemical and histological methods. No significant differences in lipid and collagen contents were detected among treatments, although the FA composition in the skin was altered depending upon the FA composition of the supplemented oils. Electron microscopy revealed that the subcutaneous tissue layers in the CLA and DHA groups were significantly thinner than that in the high linoleic acid group, whereas no differences in the thickness of dermis layers were observed among the three groups. These results suggest that skin properties in mice are readily modified by dietary FA sources within 4 wk of dietary oil supplementation.