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The three-dimensional distribution of melt in partially molten synthetic samples compositionally corresponding to diopside (90 wt.%)–anorthite (10 wt.%) and doped with PbO, WO3, MoO3, or Cs2O to enhance contrast was studied by X-ray computed tomography (CT) with synchrotron radiation. The heavy elements were strongly concentrated in the melt and contributed to an increase of the X-ray linear attenuation coefficient (LAC) of it. PbO was found to be compatible with silicate melt (>20 wt.% in solution) and incompatible with diopside crystals. Other oxides WO3 (∼10 wt.%), MoO3 (∼5 wt.%) and Cs2O (< 5 wt.%) are also soluble only in the melt. Such doping is useful not only for LAC control in X-ray CT measurements, but also for systematic control of the structure (wetting properties, distribution and connectivity) of partial melt. This technique gives basic information for discussion of the 3D distribution of partial melt having different wetting properties. As PbO was most effective in visualization of the diopside–anorthite partially molten system, CT images of the PbO-bearing sample were used for further 3D investigation of distribution. A distribution of dihedral angles at solid-melt-solid triple junctions ranging from 22 to 55° was observed with the 3D data. This range in angle distribution was probably caused by anisotropy of crystals and the result supports the argument that there is some limitation in a theoretical framework of stereology which estimates the 3D structure based on 2D observations. Investigators have begun to apply X-ray CT to the study of the 3D distribution of partial melts in rocks using synchrotron radiation. Our study on the effect of doping is one approach for developing a technique to investigate 3D melt distribution.
The in situ X-ray reciprocal space mapping (in situ RSM) of symmetric diffraction measurements during lattice-mismatched InGaAs/GaAs(001) growth were performed to investigate the strain relaxation mechanisms. The evolution of the residual strain and crystal quality were obtained as a function of InGaAs film thickness. Based on the results, the correlation between the strain relaxation and the dislocations during the film growth were evaluated. As a result, film thickness ranges with different relaxation mechanisms were classified, and dominant dislocation behavior in each phase were deduced. From the data obtained in in situ measurements, the quantitative strain relaxation models were proposed based on a dislocation kinetic model developed by Dodson and Tsao. Good agreement between the in situ data and the model ensured the validity of the dominant dislocation behavior deduced from the present study.
We report magnetic properties of [Ca2CoO3-δ]0.62CoO2 (Ca349) powders with various average size and the Bi- and Sr-doping effects on thermoelectric properties for the magnetically grain-aligned and densified Ca349 thick films. Magnetic anisotropy at 300 K depended on the initial average size of Ca349 powders and decreased with the decrease in the size. This presumably suggests that distortion of crystal structure was induced by a ball-milling process and led to the change of magnetic anisotropy. On the Bi- and Sr-doping effects, an obvious enhancement of thermoelectric properties did not emerge in the case of the Sr-doping, whereas the enhancement was observed for the Bi-doped Ca349 thick films. However, a drastic decrease of magnetic anisotropy was caused by the Bi-doping. For usage of the p-type layer in multilayered thermoelectric module, tuning of the Bi-doping levels in which both enhancement of thermoelectric properties and a certain level of magnetic anisotropy are achieved is required.
We report thermoelectric (TE) properties of mono-layer thick films of p-type [Ca2CoO3-δ]0.62CoO2 (Ca349) and n-type compounds of Ca0.9La0.1MnO3 (Mn113) and LaNi0.98Mo0.02O3 (Ni113) for the improvement of TE performance in multi-layered TE modules. In the case of magnetically aligned Ca349 film, the improvement of TE properties due to the reduction of resistivity (ρ) was achieved by optimization of hot-pressing temperature and ρ was sensitive to relative density of the Ca349 layer. For the decrease in ρ of the n-type layers, two different approaches, the choice of Ni113 as a n-type compound and usage of fine powders of Mn113, were attempted. Both approaches were effective for reducing ρ even in the sintering at ∼900°C.
The amount of residual carbon in the GaAsN film deposited by chemical beam epitaxy (CBE) is decreased by the flow rate modulation growth method (FM-CBE). The number of carbon atoms remained in the grown film increases as the growth temperature decreases. At low temperatures below 440°C, the carbon atoms are mainly originated from the nitrogen source gas mono-methylhydrazine. However, increasing the substrate temperature during the growth causes the deterioration of film qualities and the high growth temperature is not the solution for reducing the impurities. On the other hand, by intermitting the supply of gallium source triethylgallium while the arsenic and nitrogen sources are continuously supplied, the carbon concentration drastically decreases as compared with that grown by the conventional CBE growth. The results of temperature programmed desorption and ab initio calculations suggest that the desorption of adsorbates that contain C atom, such as, NHCH3, is enhanced by the FM-CBE growth, resulting in the decrease of the residual C concentration.
This is a copy of the slides presented at the meeting but not formally
written up for the volume.
The development of texture can be controlled by slip casting and EPD in a
strong magnetic field followed by heating even for diamagnetic ceramics
such as alumina. We mesured the mechanical properties of the textured
alulmina and the alumina/alumina laminar composites with different
To clarify the reaction process of Co and Fe with a oxide layer on Si substrates, the annealing processes were analyzed using spectroscopic photoemission and low-energy electron microscopy for a special surface where oxide areas and clean substrate areas (voids) coexist closely in a micrometer-order view. From analyses of XAS spectra and edge jump ratios obtained from the photoemission electron microscopy image, we clarified that Co atoms in the void area remain because of the formation of silicides, but that those on the oxide layer disappear because metallic Co atoms easily diffuse. In contrast, in the case of Fe, we found the formation of various silicides and their gradual diffusion into Si substrate even in the form of silicides.
We report the preparation of grain-aligned [Ca2CoO3−δ]0.62CoO2 (Ca349) thick films and the conversion of the easy axis of magnetization from the a-axis to the c-axis. The thick films were fabricated by a simultaneous usage of electrophoretic deposition and magnetic alignment methods (MEPD) at high deposition rate with the order of 10 mm/min. Moreover, a multi-layered thick film of Al2O3/Ca349/Al2O3/Ca0.9La0.1MnO3/Al2O3 was also fabricated by the MEPD method by the optimization of condition of each suspension. The conversion of the easy axis was performed crystallochemically for a [Bi2Sr2O4]0.55CoO2 (BiSr222) compound with the easy axis parallel to the a-axis in order to fabricate c-axis grain-oriented bulks by the magnetic alignment method. The substitution of Ca for Sr in the [(Bi0.5Pb0.5)2Sr2O4] block layer induced the change of the easy axis into the c-axis direction, and the magnetic anisotropy was increased by the partial substitution of rare earth elements of Pr, Nd, Tb and Dy for Ca. Using a compound of [(Bi0.5Pb0.5)2(Ca0.8Pr0.2)2O4]0.55CoO2, we have successfully prepared the c-axis grain-aligned bulk by the magneto-scientific method. Our present results indicate that the magneto-scientific method is one of the useful and realistic processes for production of thermoelectric modules.
The electrophoretic deposition of single-crystalline α-alumina particles dispersed in aqueous media was performed in a strong magnetic field of 10 T. The α-alumina particles in the stable suspension were aligned due to their anisotropic diamagnetic susceptibility and then deposited on a cathodic substrate. The orientation of the α-alumina crystallites was confirmed by x-ray diffraction of the sintered specimen.
The motility of the avian cloaca is under neural control, but little is known about the neural network that
accomplishes this function. This present study was designed to determine the distribution of nitric oxide-synthesising neurons in the pigeon cloaca by enzyme histochemistry for reduced nicotinamide adenine
dinucleotide phosphate-diaphorase (NADPH-d). NADPH-d-positive staining was seen in the neurons and
fibres in the cloaca. The highest density of nerve fibres was noted in the coprodeum and the lowest in the
proctodeum. In the coprodeum, NADPH-d neurons were found singly, formed small groups of 2–10
neurons, or were seen in plexuses in the muscle layer, lamina propria, or around the arterioles. Several
NADPH-d-positive neurons were also observed in the ganglia of the cloaca. NADPH-d fibres ran in the
muscle layer, lamina muscularis mucosae and lamina propria, or surrounded blood vessels. The distribution
pattern of acetylcholinesterase (AChE)-stained neurons and fibres in the cloaca was similar to that of
NADPH-d. Double staining for NADPH-d and AChE showed colocalisation of the 2 enzymes in many
neurons of the cloaca. Tyrosine hydroxylase (TH)-immunoreactive nerve fibres originating outside the cloaca
were also noted. In the urodeum and proctodeum, neurons or fibres positive for NADPH-d, AChE or TH
were scattered in the lamina propria. Nerve fibres immunoreactive for calcitonin-gene related peptide,
galanin, methionine-enkephalin, substance P, and vasoactive intestinal peptide were found sparsely in the
cloaca. Our results demonstrate that nitrergic neurons constitute a subpopulation which is closely associated
with the cholinergic system in the pigeon cloaca.
Whisker-originated short in the self-aligned contact (SAC) W polymetal gate was directly observed for the first time. Short points between gate electrodes and poly-Si plugs in the test structure were identified by emission microscope and cross-sectional TEM samples of those points were made by using focused ion beam (FIB).
Whiskers are formed during high-temperature processing such as LP-CVD SiN. We have proposed that NH3 de-oxidation step inserted in the SiN deposition sequence is effective for suppressing whisker growth.  In this study it was also confirmed that 600°C NH 3 pre-flow improved leakage current between gate electrode and contact plugs.
A Fresnel zone plate (FZP) is a micro-focusing optical element of synchrotron radiation hard X-ray. Our developed multilayer FZP produced a sub-micron size spot at the hard X-ray energy and the focusing efficiency is about 25%. However the higher efficiency FZP is required to utilize the sub-micron probe in microscopy, diffraction and imaging applications. A kinoform FZP composed of gradient refractive index phase zones has the advantage of a high focusing efficiency compared to the conventional multilayer FZP. In order to fabricate the kinoform FZP, we developed a computer-control system. The developed computer-control system automatically operates whole combinatorial deposition processes of the kinoform FZP by inputting the optical parameters of the FZP (focal length, X-ray wavelength, number of zones, zone materials).
We examined the distribution of parvalbumin in the pigeon thymus by light and electron microscopic
immunohistochemistry. Tissues were also examined by conventional electron microscopy to determine the
ultrastructure of immunoreactive cells. Parvalbumin immunoreaction was located in epithelial cells of the
cortex, which formed dense mesh-like structures. Parvalbumin-positive epithelial cells were classified into 2
types. The first comprised elongated cells. In these, the nucleus was spindle-shaped, oval, or triangular, with
a slightly irregular contour and contained rich heterochromatin peripherally. The cytoplasm was pale and
processes extended laterally or ramified among the surrounding thymocytes. This type of cell formed the
majority of immunoreactive cells. The other cell type consisted of polygonal epithelial cells. The nucleus was
oval with deep indentations. Euchromatin occupied a large part of the nucleus. The cytoplasm contained
numerous cell organelles compared with the elongated type, in particular, electron-dense vacuoles of various
sizes and often bundles of tonofilaments. Both types of epithelial cell were interconnected by desmosomes.
No secretory granules were found in the cytoplasm of elongated or polygonal cells. These results indicate the
presence of heterogeneous group of parvalbumin-immunoreactive epithelial cells and suggest the likelihood
of different functional roles for parvalbumin in the pigeon thymus.