阳极双电层电容对微生物燃料电池性能的影响

采用3种活性炭粉制备具有不同电容的阳极,研究了双电层电容阳极对单室空气阴极微生物燃料电池启动、运行、性能、阳极生物膜附着的影响。结果表明:当电极表面积相近的情况下,阳极双电层电容从0.0012 F增加到22.72 F时,微生物燃料电池启动时间缩短了68.0%,电池的最大功率密度增加了16.8倍,达到546.1 m W·m-2。扫描电子显微镜的结果表明高电容的阳极表面附着的微生物量比低电容电极的高1倍。因此,微生物燃料电池性能受阳极双电层电容的影响,而与阳极表面积的相关性小。     

双层砂井地基大变形固结方程差分解

基于砂井地基轴对称大变形固结控制方程,综合考虑双层砂井地基软土的压缩性与渗透性非线性幂函数变化、分级加荷、径向与竖向同时渗流排水、初始超静孔压几种分布模式等实际条件,采用交替方向隐式（ADI）差分法编程求解了建立的双层砂井地基大变形固结控制方程,通过算例分析验证了建立的方程与差分解法及编制程序的合理性。将本文方法应用于围海造陆工程吹填淤泥与海相沉积淤泥组成的双层砂井地基固结计算,预测的固结沉降过程较经典固结理论更接近于实测值,对双层砂井地基固结沉降过程预测进行了有益的探讨。     

局部冲刷对部分埋入单桩水平承载性状的影响

为分析局部冲刷对部分埋入桩水平承载性状的影响,利用有限元软件ABAQUS模拟水平荷载作用下部分埋入单桩的受力。根据实际工况建立了部分埋入水平受荷桩的三维有限元计算模型,并将计算结果与现场试验结果进行对比,验证了所建模型的正确性。然后,通过算例分析了冲刷角度、深度、桩直径、桩顶约束条件和桩自由段长度对部分埋入桩水平承载性状的影响。分析结果表明:局部冲刷深度比冲刷角度对部分埋入桩的水平承载性状影响更大,局部冲刷对直径较大的桩体承载能力影响也更大,自由段长度的增大减小了桩体水平承载力,因此,在研究冲刷对桩基水平承载性状的影响时,应结合桩顶约束条件综合考虑。     

双层超固结软黏土地基一维非线性固结分析

本文通过引入固结土层孔隙比与固结压力和渗透系数之间的非线性经验模型，建立双层超固结饱和软黏土地基非线性固结控制方程，并基于半解析法，编制了相应的计算程序。利用该程序，针对不同排水条件、变荷载、自重应力沿深度实际分布等条件分析双层超固结饱和软黏土地基一维非线性固结性状。计算结果表明，双层超固结软黏土地基比正常固结软黏土地基沉降小、固结发展快。荷载的大小、上下土层先期固结压力、土体压缩性和渗透性的变化等对双层地基的固结性状均有明显影响。     

首都机场职工体育活动综合馆钢网壳设计

首都国际机场职工体育活动综合馆是中国民航总局为活跃职工的业余生活。在机场附近建造的一座集比赛、健身、休闲和娱乐于一体的综合性活动场所。该馆屋益采用双层筒形钢网壳结构，屋面为彩色夹芯板和局部采光玻璃。本文主要介绍了该馆钢网壳下弦多点支承在不等高的钢筋混凝土柱顶上的设计要点及技术措施。     

半透水边界双层复合地基固结解析理论

研究了考虑双面半透水、涂抹效应和应力集中效应的双层散体材料桩复合地基固结解析解及其工程应用.依据应力条件下的平衡方程和连续条件下的固结方程，由假定的无穷级数解推导出特征方程，并基于特征方程讨论了特征根取值的各种情形，进而得到了双面半透水双层复合地基的固结解析解.研究了给出的计算模型转化为求解单、双面透水双层散体材料桩复合地基以及双层天然地基固结理论的可行性，进而证明求得解具有普遍适用性.研究发现，半透水边界对固结的影响不明显；固结速率随桩径比的减小和桩体刚度的增大而增大；桩径比的作用大于桩体刚度的作用.     

One-dimensional consolidation of double-layered soil with non-Darcian flow described by exponent and threshold gradient

Based on non-Darcian flow law described by exponent and threshold gradient within a double-layered soil, the classic theory of one-dimensional consolidation of double-layered soil was modified to consider the change of vertical total stress with depth and time together. Because of the complexity of governing equations, the numerical solutions were obtained in detail by finite difference method. Then, the numerical solutions were compared with the analytical solutions in condition that non-Darcian flow law was degenerated to Dary’s law, and the comparison results show that numerical solutions are reliable. Finally, consolidation behavior of double-layered soil with different parameters was analyzed, and the results show that the consolidation rate of double-layered soil decreases with increasing the value of exponent and threshold of non-Darcian flow, and the exponent and threshold gradient of the first soil layer greatly influence the consolidation rate of double-layered soil. The larger the ratio of the equivalent water head of external load to the total thickness of double-layered soil, the larger the rate of the consolidation, and the similitude relationship in classical consolidation theory of double-layered soil is not satisfied. The other consolidation behavior of double-layered soil with non-Darcian flow is the same as that with Darcy’s law.     

波浪对双层圆弧型贯底式开孔介质防波堤的绕射

为研究波浪对双层圆弧型贯底式开孔介质防波堤的绕射问题,利用比例边界有限元方法(SBFEM)建立该问题的半解析解模型.分析时将双层圆弧延伸构建出2个虚拟同心圆可将整个流场可划分成2个有限域和1个无限域.利用变分原理推导出了关于势函数的各个子域SBFEM方程,并对SBFEM方程进行了求解.数值算例验证了该方法是一种只需离散最外边界而且用很少单元便能得到精确结果的高效算法.给出了短峰波波向、相对波数、内外半径比、圆弧段的位置、张角以及孔隙影响系数等因素对整个结构波浪绕射的影响.结果表明,双层圆弧型贯底式开孔介质防波堤与以上参数的变化密切相关.     

Novel technology on preparation of double-layered pellets for sulfur and arsenic-bearing gold concentrates

Double-layered pellet （DLP） roasting is a novel pretreatment method for sulfur and arsenic-bearing gold concentrates. In this process, preparation of DLPs is a fundamental step which is required to produce DLPs with favorable mechanical strength and thermal stability. Studies were carried out to investigate the affecting factors and conditions on the preparation and properties of DLPs. The results show that moisture content has significant influence on DLPs preparation. With the increase of moisture content in the range of no more than 9.8%, drop resistance and compressive strength of green DLPs are raised and the pelletizing dynamics is improved accordingly. The optimum conditions are determined as moisture content of 9.8%, coating time of 14-16 min, drying temperature 〈80 ℃and drying gas velocity 〈1.2 m/s. When DLPs prepared under these conditions are roasted at 600 ℃ for 1 h, favorable removal and solidifying rates can be obtained, in which the removal rates of arsenic and sulfur are 94.38% and 82.55%, and the solidifying rates of arsenic and sulfur reach 99.62% and 99.79%, respectively. These results promise industrial application of DLP roasting.