新型蠕化剂的研制

介绍了新型蠕化剂的研制过程。研究得出用RE—Cu—Zn—Mg—Si—Fe合金（ωRE=15％-22％），ω（Cu）15％-22％。ω（Zn）2．5％-4％，ω（Mg）0—3％，ω（Si）29％-32％，Fe余量）作蠕化剂，其适宜加入量范围宽，便于蠕铁生产的稳定。     

金鸡山隧道拓宽方案离散元分析

结合福州金鸡山隧道拓宽改造工程,通过建立离散元计算模型,对拓宽改造方案进行了优化分析.分别研究了不同方案下隧道围岩屈服、围岩变形、拱顶下沉、衬砌内力特征及中夹岩柱应力状态,研究结果表明:方案1能够保证满足隧道建成后的安全要求,对既有建构筑物的扰动最小,且隧道整体受力状态较好,是最佳方案.研究结果可为今后类似工程的设计、施工提供借鉴与参考.     

基于凸优化的最小旁瓣恒定束宽时域宽带波束形成

 提出了基于凸优化的适用于任意结构基阵的最小旁瓣恒定束宽时域宽带波束形成方法.首先将基阵波束响应表达成一组有限脉冲响应(FIR)滤波器权值的线性函数,然后采用基于恒定束宽限制条件的最小旁瓣优化准则设计FIR滤波器权值.同时对滤波器系数进行范数约束以及对干扰方向设置展宽零陷来提高波束形成器的鲁棒性.将期望波束响应的设计过程与实际波束响应的逼近过程融合在一起进行优化搜索,获得了全局最优解.该波束形成器设计问题被转化成凸优化问题求解,仿真结果验证了所提方法的有效性.     

复合受力下钢筋混凝土单箱多室箱梁抗剪分析

为了确定钢筋混凝土单箱多室箱梁在剪扭组合作用下的极限承载力,该文基于箱梁剪扭理论,提出了一种通过验算单箱多室箱梁每个板件的极限抗剪承载力来确定整个断面剪扭承载力的方法。笔者通过试验对该方法进行了验证,试验结果表明,采用该方法计算单箱多室箱梁的抗剪扭极限承载力是可行的,按此方法计算得到的单箱多室箱梁的抗剪扭极限承载力的安全储备系数可以达到2.54。该文为钢筋混凝土单箱多室箱梁在剪扭作用下极限荷载的确定提供了理论计算方法,利用该方法能较好的预测单箱多室箱梁在剪扭作用下的极限荷载。     

Structural tuning of photoluminescence in nanoporous anodic alumina by hard anodization in oxalic and malonic acids

ABSTRACT: We report on an exhaustive and systematic study about the photoluminescent properties of nanoporous anodic alumina membranes fabricated by the one-step anodization process under hard conditions in oxalic and malonic acids. This optical property is analysed as a function of several parameters (i.e. hard anodization voltage, pore diameter, membrane thickness, annealing temperature and acid electrolyte). This analysis makes it possible to tune the photoluminescent behaviour at will simply by modifying the structural characteristics of these membranes. This structural tuning ability is of special interest in such fields as optoelectronics, in which an accurate design of the basic nanostructures (e.g. microcavities, resonators, filters, supports, etc.) yields the control over their optical properties and, thus, upon the performance of the nanodevices derived from them (biosensors, interferometers, selective filters, etc.).     

Tuning nanoporous anodic alumina distributed-Bragg reflectors with the number of anodization cycles and the anodization temperature

The influence of the anodization temperature and of the number of applied voltage cycles on the photonic properties of nanoporous anodic alumina-based distributed-Bragg reflectors obtained by cyclic voltage anodization is analyzed. Furthermore, the possibility of tuning the stop band central wavelength with a pore-widening treatment after anodization and its combined effect with temperature has been studied by means of scanning electron microscopy and spectroscopic transmittance measurements. The spectra for samples measured right after anodization show irregular stop bands, which become better defined with the pore widening process. The results show that with 50 applied voltage cycles, stop bands are obtained and that increasing the number of cycles contributes to enhancing the photonic stop bands (specially for the case of the as-produced samples) but at the expense of increased scattering losses. The anodization temperature is a crucial factor in the tuning of the photonic stop bands, with a linear rate of 42 nm/°C. The pore widening permits further tuning to reach stop bands with central wavelengths as low as 500 nm. Furthermore, the results also show that applying different anodization temperatures does not have a great influence in the pore-widening rate or in the photonic stop band width.     

Experimental study on the mechanical behavior of shored mechanically stabilized earth walls for widening existing reinforced embankments

Shored mechanically stabilized earth (SMSE) walls have been increasingly applied in embankment widening projects because of their good mechanical performance, simple construction, low cost, and low site requirements. In this paper, several large-scale model tests were conducted to explore the mechanical behavior of the composite structures with different connection forms and relative densities, and the wall deformation, earth pressure, reinforcement strain, potential failure surface and the effects of the connection forms behind SMSE walls were also analyzed. The results show that the deformation of SMSE walls is mainly concentrated on the upper middle part, showing a “bulging” failure trend. The deformation of the SMSE walls can be effectively controlled by improving the relative density and adopting a “sandwich” connection behind the walls. The horizontal earth pressure against the SMSE wall facing shows a “K”-shaped distribution, and the vertical earth pressure is large in the upper part and small in the lower part. The potential failure surface originated at the junction of the old and new retaining walls, forming a “double-line” failure surface. For a “sandwich” connection, the failure surface moves forward and occurs where the primary and secondary reinforcements overlap, and this connection form is recommended in engineering practice.     

土方开挖泵吸施工工艺及施工监控

采用泥浆泵进行卡口拓宽大规模土方吸运是长江堤防施工的一个新举措和新工艺。重点介绍了天宇一号段卡口拓宽工程土方开挖施工中采用的泵吸施工工艺措施及施工监控要点，并进行了分析总结。在阴雨季节，泵吸施工受气候干扰较小，工效稳定，对于确保工程进度，具有常规机械挖运无法比拟的优势，对类似条件的土方开挖，特别是对长江堤防工程中的大规模卡口拓宽土方开挖，有一定的借鉴和参考价值。     

南城桥二次拓宽改建技术研究

在路网改造中,由于原有桥涵等级低、线形不畅及老化破损,加之沿路建筑、河道的制约等,使老桥改造成为道路改建的关键和难点。通过对南城桥二次拓宽改造的方案优化过程、主要技术措施及改建成效等方面的阐述,探讨中小桥梁老桥改建技术。     

高速路路基拓宽新老路搭接技术探究

从施工和裂缝方面分析了高速公路路基拓宽新老路搭接存在的问题,探讨了土质路基、填石路基及土石混填路基的施工技术要点,总结了影响路基压实的因素,为今后新老路基的搭接提供了参考借鉴。