38 research outputs found

    Pseudoelastic Behavior and Aging Effect in Thermoelastic In-Tl Martensite

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    In this paper, the authors report the interesting stress-strain results and an aging behavior found in single crystals of In-21, 22, 23, 24, 25 and 26 at. % Tl alloys. The stress-strain curves can be classified into three groups according to their shapes. In a high temperature region above martensitic temperature, Mₛ, while at a considerably low temperature region, superelastic loops are obtained. While at an intermediate temperature below Mₛ, the residual strain remains after removal of the applied stress, and this strain returns to zero when the specimen is heated up to above the reverse transformation temperature. That is the so-called shape memory effect. The twin boundaries migrated by the external stress were stabilized by strain aging under stress, and the activation energy for the aging process was found to be O.51±O.O3eV. The strain rate dependence of pseudo-elastic behavior is observed in the martensite phase and is explained by the dynamic aging between the moving twin boundaries and Tlatoms

    Effect of Grain Boundary on Pseudo-elastic Deformation of Cu-Zn-Si Bicrystal of Shape Memory Alloy

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    Two sorts of Cu-Zn-Si pseudo-elastic bicrystals of shape memory alloy were tested in tension to know the effects of the grain boundary. The remaining martensites were observed in the vicinity of the grain boundary, and the propriety of analyses through use of m/m。 and Nᵢj values and of the compatibility of the plastic strain were studied. The variant of martensite occurring primarily in each grain during deformation, can be predicted with use of them value (shear factor of the variant) in general. The analyses through use of m/mᵢ and Nᵢj values and the equations of the plastic strain compatibility are sufficiently useful to know the variant of martensite nucleated additionally in the vicinity of the grain boundary. However, the possibility of activation of slip must be considered in this case. The reversible strain of the isoaxial bicrystal is larger than that of the non-isoaxial bicrystal. However, the relation between the reversible strain and the misorientation of bicrystal is not yet sufficiently known

    Moving object detection from a point cloud using photometric and depth consistencies

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    ICPR 2016: 23rd International Conference on Pattern Recognition, Dec 4-8, 2016, Cancun, Mexico3D models of outdoor environments have been used for several applications such as a virtual earth system and a vision-based vehicle safety system. 3D data for constructing such 3D models are often measured by an on-vehicle system equipped with laser rangefinders, cameras, and GPS/IMU. However, 3D data of moving objects on streets lead to inaccurate 3D models when modeling outdoor environments. To solve this problem, this paper proposes a moving object detection method for point clouds by minimizing an energy function based on photometric and depth consistencies assuming that input data consist of synchronized point clouds, images, and camera poses from a single sequence captured with a moving on-vehicle system

    Diagnostic Performance of 11C-choline PET/CT and FDG PET/CT in Prostate Cancer

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    We compared 11C-choline and FDG PET/CT scan findings for the staging and restaging of prostate cancer. Twenty Japanese prostate cancer patients underwent 11C-choline and FDG PET/CT before (n=5) or after (n=15) treatment. Using a five-point scale, we compared these scanning modalities regarding patient- and lesion-based diagnostic performance for local recurrence, untreated primary tumor, and lymph node and bony metastases. Of the 20 patients, documented local lesions, and node and bony metastases were present in 11 (55.0%), 9 (45.0%), and 13 (65.0%), respectively. The patient-based sensitivity/specificity/accuracy/area under the receiver-operating-characteristic curve (AUC) values for 11C-choline-PET/CT for diagnosing local lesions were 90.9% /100%/ 95.0% / 1.0, whereas those for FDG-PET/CT were 45.5% /100%/ 75.0% / 0.773. Those for 11C-choline-PET/CT for node metastasis were 88.9% /100%/ 95.0% / 0.944, and those for FDG-PET/CT were 44.4%/100%/75.0%/0.722. Those for 11C-choline-PET/CT for bone metastasis were 84.6%/100%/90.0%/0.951, and those for FDG-PET/CT were 76.9% /100%/ 85.0% / 0.962. The AUCs for local lesion and node metastasis differed significantly (p=0.0039, p=0.011, respectively). The lesion-based detection rates of 11C-choline compared to FDG PET/CT for local lesion, and node and bone metastases were 91.7% vs. 41.7%, 92.0% vs. 32.0%, and 94.8% vs. 83.0% (p=0.041, p=0.0030, p<0.0001), respectively. 11C-choline-PET/CT is more useful for the staging and restaging of prostate cancer than FDG-PET/CT in Japanese men

    Development and practice of laboratory seismic experiment course and teaching material for understanding realistic seismic refraction survey

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    地球科学の現象の中でも大気海洋物理や火山分野に比べて、地震学で扱うものは視認しにくく、断層破壊や波動伝播に関する動的な実験教材は殆ど存在しない。地震の源たる断層も教科書では静的なイメージで語られがちである。我々は、実際に見て触って実感できる教材や実習が必要と考え、動的な現象としての地震像をわかりやすく伝えるための実験演習教材を開発する研究に着手した。ここでは、屈折法地震探査によって地下構造を推定する方法とその重要性について学習するための実験演習教材を紹介する。具体的には、寒天模擬地殻に力や振動を与え、波(S波)が伝播する様子を高速カメラで撮影した画像のスロー再生を実際に目で見ることで、実感をともなう理解を促しながら原理を学習する内容となっている。これまで実施した高校生向けの実習や一般公開等での展示などの実用例、およびその教育的効果について報告する。物理探査学会第132回(平成27年度春季)学術講演会(平成27年5月11日~13日, 早稲田大学西早稲田キャンパス
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