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Search Results: 1 - 10 of 116731 matches for " 邹炳文 "
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PBL抗剪连接件疲劳后的剩余力学性能研究
,黄侨,,
- , 2017,
Abstract: 为研究钢-混凝土组合结构中PBL(Perfobond Leiste)抗剪连接件在疲劳荷载作用后的力学性能退化规律,设计并制作了9个PBL连接件的推出试件分别进行静力和疲劳试验.其中3个试件为静力破坏试验,重点关注了试件的破坏模式、极限承载力及荷载-滑移曲线.其余6个试件为在经历一定疲劳荷载循环次数后进行静力破坏试验,以疲劳循环次数,疲劳荷载比为参数变量,得到在不同疲劳参数作用后,PBL连接件的极限承载力、残余滑移量、抗剪刚度等力学性能的变化情况.研究结果表明,PBL连接件具有较好的延性,其静载和疲劳后静载的破坏模式均为一侧贯穿钢筋剪断、另一侧贯穿钢筋屈服.疲劳荷载比对PBL连接件剩余承载力影响较大,在同样经历了300万次的循环加载后,荷载比为05的极限承载力基本没有下降,而荷载比为07的承载力仅为初始静载试验的761%;在相同荷载比(06)情况下,PBL连接件的承载力随疲劳加载次数呈先慢后快的非线性退化趋势.相对于荷载比而言,残余滑移量对疲劳循环次数更为敏感.抗剪刚度在整个疲劳加载过程中基本保持不变.
In order to study the degradation law of the mechanical properties of PBL (Perfobond Leiste) shears connectors in steel-concrete composite structure under fatigue load,nine push-out PBL connectors were designed and fabricated to perform the static and fatigue tests.Among them,three static tests focused on examining the failure mode,ultimate load-carrying capacity and load-slip curves.The remaining 6 specimens were prepared for the static failure tests after a certain number of fatigue loads.Taking the cyclic number and the fatigue load ratio as the variables,the variation of the mechanical properties of the PBL connector,such as ultimate load-carrying capacity,residual slip,and shear stiffness,were obtained.The results show that:(1) PBL connector exhibits good ductility,and failure mode of the static and fatigue test specimens is all that one side of perforated steel bar cut and the other side yielded.(2) Fatigue load ratio has a significant effect on the residual strength of PBL connector.After 300 million number of cyclic loading,the ultimate load-carrying capacity is not degraded when the load ratio is 0.5,whereas it is reduced to 76.1% of initial value when the load ratio is 0.7.In the case of the same load ratio of 0.6,the load-carrying capacity tends to be slow first and then fast with the increase of fatigue cyclic number.(3) Compared with the load ratio,the residual slip is more sensitive to the fatigue cyclic number.Meanwhile,the shear stiffness is constant in the whole loading process.
开孔板连接件剩余承载力计算模型及试验验证
,黄侨,,
- , 2017, DOI: 10.3785/j.issn.1008-973X.2017.08.008
Abstract: 为了研究组合结构桥梁中开孔板连接件在一定疲劳荷载循环次数后抗剪承载力的退化问题,提出基于疲劳累积损伤效应的开孔板连接件剩余承载力计算方法.采用弹性地基梁法分析开孔板连接件在线弹性阶段的受力特征,得出在给定疲劳荷载幅值下贯穿钢筋和混凝土榫的应力幅值;参考已有文献中混凝土与钢筋的疲劳寿命模型计算出各自的疲劳寿命,得到两者在一定疲劳循环次数后的损伤;根据贯穿钢筋和混凝土榫对整体承载力的贡献比例,计入相应的损伤度,推导出开孔板连接件疲劳后的剩余承载力计算模型.通过开孔板连接件剩余承载力的推出试验结果进行验证.结果表明:提出的模型的计算结果不仅与试验结果吻合良好,且偏于安全.
Abstract: A residual bearing capacity calculation model of Perfobond connector based on the fatigue cumulative damage effect was propased in order to analyze the degradation issues of shear capacity of Perfobond connectors after a certain number of fatigue loading in composite bridges. The mechanical characteristics of Perfobond connector in the linear elastic stage was analyzed by elastic foundation beam method. The stress amplitudes of transverse rebar and the concrete in the hole were calculated at a given fatigue load amplitude. The fatigue life of steel and concrete was obtained with reference to their models in the existing literature, respectively. The damage of the two materials was calculated under a certain number of fatigue loads. A residual bearing capacity calculation model for Perfobond connector was deduced according to the contribution proportion of steel and concrete for the whole bearing capacity and considering the corresponding damage degree. It was verified by the results of the residual bearing capacity push-out tests for the Perfobond connectors. Results showed that the calculated values of the proposed model accorded well with the experimental results, and was considerably conservative.
岩盐型ZnO纳米微粒的光电子发射结构
,汤国庆,张桂兰,
物理学报 , 1995,
Abstract: 报道了岩盐型氧化锌纳米微粒的X射线光电子发射结构,发现其中3d电子的强烈成键作用,还存在着3d-4sp杂化和离域电子弛豫态的贡献,表现出与纤锌矿型明显的差异.
热处理对表面包覆纳米In2O3有机溶胶光学性质的影响
吴晓春,汤国庆,,余保龙,张桂兰,
科学通报 , 1996,
Abstract: 1983年美国Hugles研究所的Jain和Lind在市售的半导体微晶掺杂的滤波玻璃中发现了半导体纳米材料大的三阶非线性效应和超快速的时间响应.从此半导体纳米材料作为一种新的非线性光学材料引起了科学界的瞩目,对它的研究也蓬勃开展起来.体相In_2O_3是一类具有较大非共振三阶光学非线性的无机材料(λ=1.9μm,x~(3)=1700×10~(-15)esu.为了研究其在纳米尺度下光学非线性的变化和寻找高光学非线性的半导体纳米材料,我们采用热水解法合成了表面包覆有硬脂酸的纳米In_2O_3有机溶胶体系.采用表面包覆是基于以下两方面的考虑:首先,纳米材料由于其微小的颗粒和大的表面积,是热动力学上不
亚甲兰对纳米CdS有机溶胶体系光谱性质的影响
汤国庆,张桂兰,,余保龙,
科学通报 , 1996,
Abstract: 本文合成了亚甲兰(MB)分子掺杂的纳米CdS反向胶束体系,首次研究了亚甲兰分子对纳米CdS反向胶束体系光谱性质的影响,以期进一步了解纳米反向胶束体系进行功能分子掺杂后其光学性质的改变,进而开发复合纳米体系的应用.样品的吸收光谱表明当MB分子浓度较低时,MB吸附在纳米CdS表面;其带正电荷的极性头部分与阴离子表面活性剂发生某
热处理对表面包覆纳米In2O3有机溶胶光学性质的影响
吴晓春,汤国庆,,余保龙,张桂兰,
科学通报 , 1996,
Abstract:
亚甲兰对纳米CdS有机溶胶体系光谱性质的影响
汤国庆,张桂兰,,余保龙,
科学通报 , 1996,
Abstract:
热毒平抗中暑内毒素血症机制研究
杨光,,,万为人,郭进强,
中国公共卫生 , 2005, DOI: 10.11847/zgggws2005-21-12-05
Abstract: ?目的探讨中药复方制剂热毒平抗中暑内毒素血症的机制,为该类药物在重症中暑治疗中的使用打下基础。方法在干球温度(34.5±0.5)℃,相对湿度(60±5)%的条件下建立小鼠中暑模型,将40只小鼠随机分为热毒平组、西黄芪胶组、生理盐水组、高温对照组和正常对照组。用试剂盒检测血中肿瘤坏死(TNF-α)、超氧化物歧化酶(SOD)和丙二醛(MDA)活性,中性红法观察小鼠腹腔巨噬细胞的吞噬功能,四甲基偶氮噻唑蓝(MTT)法观察其能量代谢水平。结果热毒平组小鼠血中TNF-α的值低于西黄芪胶组、高温对照组、生理盐水组(P<0.001),与正常对照组相近;SOD和MDA含量分别高于和低于西黄芪胶组、高温对照组、生理盐水组(P<0.001),与正常对照组相近;腹腔巨噬细胞的吞噬能力高于西黄芪胶组、高温对照组、生理盐水组(P<0.001),与正常对照组相近;能量代谢水平高于其他4组(P<0.001)。结论抗脂质过氧化、增强巨噬细胞吞噬能力,是热毒平抗中暑内毒素血症的主要机制之一。
不同制备条件对纳米Bi~2O~3发光的影响
吴晓春,汤国庆,张桂兰,,余保龙,
化学学报 , 1996,
Abstract: 本文用微乳液法合成了不同表面活性剂包覆的和反应物阴阳离子配比不同的纳米Bi~2O~3有机溶胶。发现阴阳离子配比对纳米体系的发光有很大影响,不同的表面包覆剂对发光的影响则较小,并对此进行了解释。
TiB2-TiN复合陶瓷刀具材料的显微结构和力学性能研究
谷美林,黄传真,,,刘增
材料工程 , 2006,
Abstract: 热压烧结制备了不同TiN含量的复合陶瓷刀具材料TiB2-TiN-(Ni,Mo),对其性能测试表明,随着TiN含量的增加,材料的抗弯强度和断裂韧度逐渐提高,但是材料的硬度在TiN的含量达到40%(体积分数)时却大幅度降低.利用X衍射(XRD)、扫描电镜(SEM)和能谱(EDAX)分析了复合材料的物相和显微组织,结果表明,烧结过程中生成了MoNi相;随TiN含量增加,材料从以沿晶断裂为主转变为同时有沿晶断裂和穿晶断裂的断裂模式;裂纹扩展过程中有金属颗粒桥连现象.分析认为,材料的主要增韧机制是延性相颗粒桥连和裂纹偏转.
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