摘要：In order to research the mechanical response of continuously reinforced concrete pavement on foam concrete interlayer for a two-way curved arch bridge, the elliptical vehicle load is translated into the rectangular load based on the equivalence method. Then, a three-dimensional finite element model of the whole bridge is established. The reliability of the model is verified. Additionally, the mechanical response of continuously reinforced concrete pavement under vehicle loading is analyzed. Finally, the most unfavorable loading conditions of tensile stress, shear stress and vertical displacement are determined. The results show that the most unfavorable loading condition of tensile stress, which is at the bottom of continuously reinforced concrete pavement on the two-way curved arch bridge, is changed compared with that on homogeneous foundation. The most unfavorable loading condition of shear stress at the top is also changed. However, the most unfavorable loading condition of vertical displacement remains unchanged. The tensile stress at the bottom of about 1/4 span of the longitudinal joint, the shear stress at the top of intersection of transverse and longitudinal joint, together with the vertical displacement at the central part of longitudinal joint, are taken as design indices during the structural design of continuously reinforced concrete pavement on the two-way curved arch bridge. The results are helpful for the design of continuously reinforced concrete pavement on unequal- thickness base for the two-way curved arch bridge.

摘要：针对模型预测控制算法参数依赖性问题以及传统扰动观测器应用于双有源桥变换器中存在估计补偿滞后于外部扰动、固定增益无法适应外部宽范围干扰变化等缺点,提出一种基于自适应线性扩张状态观测器的无模型预测电压控制策略。首先,结合预测控制与无模型控制方法构建双有源桥变换器的电压预测超局部模型,代替传统物理模型,降低参数依赖;其次,设计线性扩张状态观测器对超局部模型中动态部分进行反馈补偿,提高控制精度。同时在线拟合电压误差趋势,自适应调整观测器带宽,实现超前补偿;最后,设计成本函数,求解最优移相比,实现无模型预测电压控制。实验结果验证了该方法在提升系统鲁棒性和动态性方面的有效性。

摘要：In order to study the influence of longitudinal slope on the mechanical response of steel deck pavement,a method of slope-modulus transformation was proposed for the mechanical analysis of the steel deck pavement based on the time-temperature equivalence *** the mechanical action on a slope,a finite element model of the deck pavement was established to determine the critical load position of tensileand shear stress of the steel deck ***,the influence of longitudinal slope on the mechanical response of the deck pavement under the conditions of uniform speed and emergency braking was *** results indicate that the maximum transverse tensile stress at the pavement surface and the maximum transverse shear stress at the pavement bottom are always greater than their longitudinal counterparts under uniform *** emergency braking,however,the critical slope gradient of t e maximum transverse and longitudinal tensile stress at t e pavement surface is 6%.The maximum longitudinal shear stess at t e pavement bottom is always greater ta n t e maximum tansverse shear *** stidy is helpful in t e strctural design of large longitudinal slope steel deck pavements.

摘要：针对三相交错并联Buck变换器在外部干扰下影响系统鲁棒性和动态性能的问题,本文提出一种基于自适应超螺旋滑模观测器的无模型预测控制策略。首先,建立超局部模型代替原有的数学模型,设计自适应超螺旋滑模观测器估计超局部模型中的动态部分。然后,引入最小二乘法预测电流误差趋势,动态调整观测器增益矩阵。最后,构建离散方程,设计代价函数,实现无模型预测控制。实验结果验证了所提算法可以有效抑制因外部扰动产生的稳态误差,且相较于传统无模型预测控制具有更好的鲁棒性和动态性能。

摘要：Mg_(2)Si基热电材料是中温区间最有前途的热电材料之一。为了提高Mg_(2)Si基热电接头的界面性能,提出了一种新型电极材料Mg_(2)SiNi_(3)作为Mg_(2)Si的电极材料,并采用放电等离子烧结技术(SPS)实现了Mg_(2)SiNi_(3)和Mg_(2)Si的连接。同时,测试分析了所得接头的界面微观形貌、界面电性能、力学性能以及稳定性。结果表明,Mg_(2)SiNi_(3)与Mg_(2)Si烧结后形成了完整的冶金结合,界面处各组成元素均实现了均匀过渡;界面接触电阻得到了有效地优化,而且接头以及界面稳定性良好;时效前后,界面性能均未出现大幅的退化。Mg_(2)SiNi_(3)的提出为Mg_(2)Si基热电器件设计和集成提供了一种新的思路。

摘要：针对双有源全桥变换器因建模偏差与参数扰动等因素导致的系统控制性能下降问题,提出一种基于超局部的无模型预测控制策略。构建仅包含控制输入、输出和参数扰动项的超局部模型,降低模型参数依赖性;将未知扰动项集总扩张成一个新的状态变量,设计线性扩张状态观测器进行估计并补偿,提升系统鲁棒性;构建离散化预测方程和成本函数,得到最优控制移相比,实现移相控制。实验结果验证了该无模型预测控制方法的有效性。

摘要：随着高强高性能混凝土在国内的广泛应用,以强度为设计指标的传统混凝土配合比设计方法已不能满足高强高性能混凝土配合比设计的要求。以广州珠江新城西塔工程C80高强高性能混凝土实际施工配合比为例,详细介绍了国内高性能混凝土配合比全计算设计方法(简称全计算法)和国外Mehta、Aitcin高性能混凝土配合比设计方法(简称Mehta、Aitcin法)。实践表明广州珠江新城西塔工程C80高强高性能混凝土的配合比设计符合以强度、工作性、耐久性为设计指标的混凝土配合比全计算法和Mehta、Aitcin法的要求。

摘要：超高性能混凝土(含5 mm以上粗骨料)由于其抗压强度高、耐久性强等优异特点,是一种节材、节地、节能的新型建筑材料,是国内、外混凝土技术的发展趋势。但由于其胶凝材料用量较大,水胶比较低,拌合物黏稠导致其泵送能力较差,易发生堵泵、爆管等事故,阻碍其在工程中的大量应用。通过合理的配合比设计、配制和生产了含有粗骨料100 MPa以上、可超高泵送的超高性能混凝土。通过采用矿渣粉、粉煤灰、硅粉等矿物掺合料复配设计,优化配合比的相关参数,得出配制100 MPa以上的超高强混凝土时,应适量增加矿物掺合料的掺量,提出提高水灰比,降低水胶比的设计方法更合理。

摘要：将—COOM基团引入传统氨基磺酸盐系高效减水剂分子结构中,开发了一种新型的高效减水剂——氨羧类高效减水剂。研究了自制磺化单体M用量、甲醛用量、甲醛滴加速度及反应溶液浓度对氨羧类高效减水剂性能的影响。结果表明,氨羧类高效减水剂减水率高,与水泥适应性优于萘系高效减水剂及传统氨基磺酸盐高效减水剂。

摘要：针对机车IGBT模块应用失效后发生炸损,造成失效原因很难查找的问题,分析IGBT模块在应用工况下的开关状态,得出5种失效模式类型。结合厂内和现场失效模式分布统计,对5种失效模式和早期失效以及应用过程中引起的失效进行原因分析,最后从应用和器件2个维度针对性提出设计改进意见。