493 publications from this institution
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硫酸溶液を用いたモルタルの薄片供試体による最大60日間における浸漬実験を行った。その目的は，浸漬後に曲げ試験およびせん断試験を行うことで，硫酸劣化によりセメント水和組織が変質した薄片供試体における力学的性質の挙動を抽出することにある。本研究において，曲げ試験から得られる荷重変位曲線から逆解析により引張特性（弾性係数，引張強度，破壊エネルギー，引張軟化曲線）を同定し，同一試験体を用いてせん断試験を行うことでせん断強度を測定した。加えて，物理的性質として力学試験後の薄片供試体の水和物量（CH，C-S-H），析出物，空隙率，細孔径分布を測定することで，物理的性質と力学的性質の変化を関連付けた。最終的に，硫酸劣化による物理的性質の変化が力学的性質に及ぼす影響は，弾性係数と引張強度および破壊エネルギーとせん断強度とで異なることを明らかにした。さらに，空隙と強度の関係に基づく既往の提案モデルの適用性を評価した。
回転ひび割れモデルを用い, コンクリートの応力-ひずみ関係に引張側, 圧縮側とも破壊エネルギーを導入した有限要素法解析により, せん断破壊となるRC梁の数値解析を行った. その結果, せん断補強を行わないRC梁に対しては, 斜めひび割れの再現性に問題はあるものの, 斜め引張破壊, せん断圧縮破壊といった破壊モードに関わらず, せん断挙動をある程度の精度で捉えることができた. また, 破壊エネルギーの導入により解析結果の要素寸法依存性を軽減することができ, せん断強度の寸法効果を表現できた. せん断補強筋を有するRC梁の解析では, せん断補強筋の効果を過小評価する傾向が示唆された結果となった.
8177 Purpose: Recent preliminary data in Japan indicate the usefulness of gefitinib to advanced non-small cell lung cancer patients. We investigated those Gefitinib effective examples in non-small cell lung cancer patients with poor performance status (3 or 4). Methods: It was aimed at the patient by whom written informed consent about gefitinib use was obtained among those to whom we judged gefitinib use to be suitable. Results: From July 2002 to December 2003, 53 patients treated with gefitinib 250mg/day. Therapy was continued until disease progression in the absence of significant toxicity. There were 38 men and 15 women, ages ranged from 49–89 years. Performance status (PS) was 0/1/2/3/4 in 6/17/12/14/4. 11 men and seven women were PS3 or 4. The main side effects were skin rash, nausea and diarrhea. Drug induced pneumonia was observed in one case. Bone marrow toxicity was not seen. Improvement of DIC was observed in two cases. Regression of brain metastases was observed in one case. Five cases were confirmed that body fluid collection was decreased significantly. Conclusion: Gefitinib can be prescribed for the patient also in a case with poor performance status comparatively safely, and is useful to condition relief. No significant financial relationships to disclose.
Shear failure after flexural yielding is a typical failure mode for a reinforced concrete (RC) member subject to cyclic load, and it is caused by the phenomenon that the initial shear strength is decreased with the increasing plastic ductility until the shear capacity degrades to be lower than the flexural strength. In this study, the flexure-shear behaviors of a number of RC columns with a relatively wide range of crucial structural factors involving tensile reinforcement ratio, shear reinforcement ratio, shear span-depth ratio (covering deep and slender columns) and axial compression load were simulated by the Three Dimensional Rigid-Body-Spring-Method, and the degradation behaviors of shear strength of all specimens were quantitatively evaluated to comprehend the effect of the structural factors. Moreover, the degradation behaviors of shear strength were decoupled into the degradation behaviors of shear resistance components (beam action, arch action, truss action, concrete contribution for beam action) to clarify the mechanism of shear failure after flexural yielding for the RC columns at various crucial structural factors. Consequently, the effect of crucial structural factors on the degradation behaviors of shear strength and shear resistance components were understood and it was concluded that the stepwise degradation of arch action was the dominant mechanism for the investigated structural factors for the shear failure after flexural yielding of RC column. This paper is an extended version in English from the authors' previous publication [Nakamura, H., Furuhashi, H., Yamamoto, Y. and Miura, T., (2015). "Evaluation of shear strength degradation of RC member subjected to cyclic loading." Journal of JSCE E2, 71(1), 48-57. (in Japanese)].
Evaluation of water absorption in concrete is regarded as an important indicator for assessing the causes of its deterioration and durability. Traditionally adopted methods for durability assessment in concrete materials, however, lack in providing real-time monitoring of the absorption process and that about the material deformability at surfaces (volumetric changes) caused by swelling in cement hydrates (i.e. C-S-H). In this study, a one-dimensional water absorption test was performed on small-size mortar specimens of three different strengths, and their top (flattened) surface was continuously monitored for volume changes by utilizing surface strain gauges along with DICM. After the water absorption test, the same specimens were tested for mechanical properties such as compressive strength and Young’s modulus. Moreover, the water absorption characteristics, like depth/rate, were evaluated in DICM by tracing changes of waterfront positions with the progression of strains during the water absorption process in mortars. Additionally, the surface strain gauges confirmed the accuracy of strains evaluated by DICM. The absorption characteristics obtained from observations in DICM were correlated with the mechanical properties and expansion strain of the test specimens. The results indicated that the durability properties were not only related to the water absorption rate but also to the mechanical properties and volume changes due to saturation.
