282 research outputs found

    3D 6DOF Manipulation of Micro-object Using Laser Trapped Microtool

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    Proceedings of the 2006 IEEE International Conference on Robotics and Automation, Orlando, Florida, May 200

    Theoretical study on novel electronic properties in nanographite materials

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    Antiferromagnetism in stacked nanographite is investigated with using the Hubbard-type model. We find that the open shell electronic structure can be an origin of the decreasing magnetic moment with the decrease of the inter-graphene distance, as experiments on adsorption of molecules suggest. Next, possible charge-separated states are considered using the extended Hubbard model with nearest-neighbor interactions. The charge-polarized state could appear, when a static electric field is present in the graphene plane for example. Finally, superperiodic patterns with a long distance in a nanographene sheet observed by STM are discussed in terms of the interference of electronic wave functions with a static linear potential theoretically. In the analysis by the k-p model, the oscillation period decreases spatially in agreement with experiments.Comment: 8 pages; 6 figures; accepted for publication in J. Phys. Chem. Solids; related Web site: http://staff.aist.go.jp/k.harigaya/index_E.htm

    Surface Photovoltage Monitoring of Heavy Metal Contamination on Silicon During Chemical Cleaning in IC Manufacturing

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    The principles and application examples of recently refined,computerized surface photovoltage (SPV) method are described. The SPV method was used to optimize cleaning efficiency and to monitor \u27in-line\u27 heavy metal contamination and charge during critical processing steps for Statistical Process Control (SPC). Examples of the optimization of various cleaning steps,effects of the purity of virgin and reused chemicals, and the surface topology on cleaning efficiency will be given together with examples of SPC monitoring of real problems in processing lines. Cleanliness of incoming chemicals is not always a limiting factor and often is not related to the cleanliness of chemicals at the point of use (in the cleaning station). This new method is capable of waferscale,non- contact mapping of metal contaminants in the bulk and on the surface with sensitivities as high as 10¹⁰atoms cm-³

    Classifying breast masses in volumetric whole breast ultrasound data: a 2.5-dimensional approach

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    The aim of this paper is to investigate a 2.5-dimensional approach in classifying masses as benign or malignant in volumetric anisotropic voxel whole breast ultrasound data. In this paper, the term 2.5-dimensional refers to the use of a series of 2-dimensional images. While mammography is very effective in breast cancer screening in general, it is less sensitive in detecting breast cancer in younger women or women with dense breasts. Breast ultrasonography does not have the same limitation and is a valuable adjunct in breast cancer detection. The current study focuses on a new 2.5-dimensional approach in analyzing the volumetric whole breast ultrasound data for mass classification

    Anodic Oxidation of Narrow Region of Silicon Substrate

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    Anodic oxide films were formed on comparatively small area of silicon substrates. Constant current mode of anodization has been used for oxidation,but during oxidation processes,the current density has been changed to go through one or more stepped transitions either step-up or step-down before the completion of the processes. This modified mode of constant current anodization showed to be effective in reducing the interface state density of a silicon/silicon-oxide system. Among the various stepped transitions in the modified mode of constant current anodization,step-down transition of current density was found to be optimum in reducing the interface-state density. The structure and composition of SiO₂/Si interface regions for both large-area oxide and narrow-area oxide were also investigated by X-ray photoelectron spectroscopy (XPS). The composition of SiO₂/Si interface of narrowarea oxide showed less stoichiometry than that of large-area oxide

    Mucosal change of the stomach with low-grade mucosa-associated lymphoid tissue lymphoma after eradication of Helicobacter pylori:Follow-up study of 48cases

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    Low-grade mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach has been demonstrated to be closely linked to Helicobacter pylori (H. pylori) and to be frequently remissioned after the cure of H. pylori infection. Several previous studies have focused on proliferating lymphocytes but little is known about gastric epithelial change and the duration of the remission after the cure of H. pylori infection. We performed a long-term follow-up investigation on the effects of anti-H. pylori treatment on MALT lymphoma and chronic gastritis at the histologic and molecular levels. Forty-eight patients with low-grade gastric MALT lymphoma and 28 chronic gastritis patients in whom H. pylori infection was eradicated were studied. After eradication, 43 MALT lymphoma patients showed complete histologic remission and continuous remission was observed during follow-up for up to 43 months (mean, 17.8 months). As for epithelial changes after eradication, "emptiness of lamina propria" was more pronounced in the mucosa with MALT lymphoma than that with chronic gastritis, and its severity in MALT lymphoma cases significantly decreased during the observation period whereas the glandular area increased. Cystic change of the fundic gland also occurred more frequently in MALT lymphoma cases than chronic gastritis cases. B-cell clonality before eradication analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) was detected in almost all MALT lymphoma cases (43cases), but rare in chronic gastritis cases (6cases). After eradication, in spite of histologic regression, 21 MALT lymphoma patients had a persistent monoclonal population during the follow-up period. B-cell monoclonality preceding the malignant transformation was noted in 4 cases. These observations indicate that 1) complete histologic remission of low-grade gastric MALT lymphomas seems stable even if a monoclonal B cell population is detectable in some cases, 2) there may be a stage of disease where monoclonal B cells are present but there is no histologic evidence of MALT lymphoma, and 3) regenerative change of the damaged glands may occur in histologic regressed MALT lymphoma cases
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