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受压徐变后混凝土断裂特性及拉伸软化本构关系研究
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作者 张健 高蔚 +3 位作者 孙伟 柳尚一 李双胜 董伟 《水利与建筑工程学报》 2024年第1期76-82,共7页
为了对服役期间的混凝土重力坝进行抗裂性评估,开展受压徐变后混凝土断裂特性与拉伸软化本构关系研究。首先对混凝土棱柱体试件进行应力水平为轴心抗压强度的40%为期360 d的受压徐变试验,然后进行准静态加载条件下的三点弯曲断裂试验,... 为了对服役期间的混凝土重力坝进行抗裂性评估,开展受压徐变后混凝土断裂特性与拉伸软化本构关系研究。首先对混凝土棱柱体试件进行应力水平为轴心抗压强度的40%为期360 d的受压徐变试验,然后进行准静态加载条件下的三点弯曲断裂试验,测定混凝土的起裂韧度、失稳韧度、断裂能,采用改进的J积分法计算裂缝扩展消耗的能量,推导混凝土的软化本构关系。试验结果表明:受压徐变试验后,混凝土的抗压强度、抗拉强度、弹性模量、起裂韧度、失稳韧度、断裂能提高。受压徐变对混凝土软化本构关系有显著影响,应力自由张开位移变小,使混凝土基本力学性能以及抗裂性增强,但也使混凝土的脆性增加。 展开更多
关键词 混凝土 徐变 断裂 起裂韧度 失稳韧度 软化本构关系 脆性
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基于混合变量的0-1线性规划模型及应用
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作者 刘尚一 吴涛 《科学技术创新》 2023年第1期92-95,共4页
通过模型对混合的0-1线性规划问题进行求解,并通过具体的实例与传统的排序法、隐枚举法等进行对比,相比较于传统方法只能处理数据较少的整数的简单运算,优化的模型则能够对于计算量繁多且带有小数的数据进行有效且快速的运算处理。文中... 通过模型对混合的0-1线性规划问题进行求解,并通过具体的实例与传统的排序法、隐枚举法等进行对比,相比较于传统方法只能处理数据较少的整数的简单运算,优化的模型则能够对于计算量繁多且带有小数的数据进行有效且快速的运算处理。文中的模型简单便捷,融合性很高,只需输入相应数据,即可进行优化。 展开更多
关键词 0-1线性规划 模型 优化
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固相多肽合成中Dmab保护基的脱除研究
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作者 时华曜 范崇旭 +2 位作者 代先东 刘尚义 曹瑛 《化学研究》 CAS 2018年第3期257-263,共7页
在固相多肽合成中,Dmab作为羧基保护基具有脱保护条件温和、步骤简便、选择性高的特点,但有时脱保护效率并不稳定.为此,基于Fmoc/t Bu/Dmab三维正交保护策略,利用固相多肽合成技术设计并合成了4个肽树脂,对固相多肽合成中Glu和Asp主链... 在固相多肽合成中,Dmab作为羧基保护基具有脱保护条件温和、步骤简便、选择性高的特点,但有时脱保护效率并不稳定.为此,基于Fmoc/t Bu/Dmab三维正交保护策略,利用固相多肽合成技术设计并合成了4个肽树脂,对固相多肽合成中Glu和Asp主链和侧链羧基的Dmab保护基脱除规律进行了研究.结果显示,树脂上α-ODmab的脱保护快速、完全,β-ODmab和γ-ODmab脱保护反应较慢,可以检测到相应的中间产物(4-氨基苄酯肽),推测脱保护效率由快到慢依次为α-ODmab>β-ODmab>γ-ODmab.该结果表明Dmab作为α-COOH保护基具有较高的应用价值,但用于β-COOH和γ-COOH保护时,其脱保护条件尚不成熟. 展开更多
关键词 Dmab保护基 脱保护 固相多肽合成
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Effects of Jiazhu decoction in combination with cyclophosphamide on breast cancer in mice 被引量:4
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作者 Guan Huiting Xie Su +6 位作者 liu shangyi Xie Qing Hou Shengkai liu Huarong Zhang Yunjie Hu Yaqing Zhang Chenyu 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2019年第5期642-648,共7页
OBJECTIVE: To investigate the therapeutic effects of Jiazhu decoction (JZD) in combination with cyclophosphamide (CTX) on the growth of breast cancer in mice and to explore the possible molecular mechanisms of action.... OBJECTIVE: To investigate the therapeutic effects of Jiazhu decoction (JZD) in combination with cyclophosphamide (CTX) on the growth of breast cancer in mice and to explore the possible molecular mechanisms of action. METHODS: BALB/c mice were randomly divided into four groups of 10 (untreated model group, JZD group, CTX group, and JZD + CTX group) and subcutaneously injected with 4T1 mouse breast cancer cells. Tumors were allowed to establish for ~7 d before initiation of treatment with CTX (100 mg/kg every week by intraperitoneal injection) and/or JZD (0.015 mL of 1.65 g/mL crude drug, administered daily by gavage). The model group received equivalent volumes of vehicle on the same schedules. Tumor volumes were measured every 3 d. Mice were sacrificed after 3 weeks of treatment, and tumors were excised and subjected to RT-qPCR and western blot analysis to evaluate expression of the Wnt/β-catenin signaling pathway components β-catenin, c-Myc, and cyclin D1 at the mRNA and protein levels. RESULTS: The mean tumor volume was smaller and the growth rate was slower in the CTX and JZD + CTX groups compared with the model group (P < 0.05), and in the JZD + CTX group compared with the CTX and JZD groups (P < 0.05). Tumor growth was inhibited by 35.4% and 48.1% by CTX and JZD + CTX treatment, respectively (P < 0.001). The expression of β-catenin, c-Myc, and cyclin D1 mRNA and protein in tumors was significantly lower in mice treated with JZD or JZD + CTX compared with the untreated mice (P < 0.05), and was significantly lower in mice treated with JZD + CTX compared with either JZD or CTX alone (P < 0.05). CONCLUSION: JZD inhibited the growth of mouse breast cancer cells in vivo, possibly by reducing the expression of β-catenin, c-Myc, and cyclin D1. Combination therapy with JZD plus CTX had a more potent inhibitory effect on breast cancer growth compared with either agent alone. 展开更多
关键词 BREAST NEOPLASMS CYCLOPHOSPHAMIDE WNT signaling pathway Jiazhu DECOCTION
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Reversible Audio Watermarking Algorithm Using Non-Causal Prediction
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作者 HUO Yongjin XIANG Shijun +2 位作者 liu shangyi LUO Xinrong BAI Zhongliang 《Wuhan University Journal of Natural Sciences》 CAS 2013年第5期455-460,共6页
Reversible watermarking technique enables to extract embedded information without any loss of the host signal. For the reduction of the embedding distortion, a desirable reversible watermarking approach should exploit... Reversible watermarking technique enables to extract embedded information without any loss of the host signal. For the reduction of the embedding distortion, a desirable reversible watermarking approach should exploit efficient prediction way to generate prediction errors with a smaller magnitude for expansion embedding. In this paper, we present a reversible audio watermarking scheme based on a new non-causal prediction method and embedding strategy. The proposed non-causal prediction method provides non-integer prediction errors and the proposed expansion embedding strategy can proceed them for a lower embedding distortion. Experimental results have shown that the proposed reversible technique has a lower embedding distortion for the same embedding payload in comparison with the existing state-of-the-art works. 展开更多
关键词 AUDIO reversible watermarking non-causal prediction expansion embedding
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