加载角度对弧形加载巴西劈裂试验影响的数值研究

巴西劈裂试验具有试件加工方便、试验易于实现等优点,是测试岩石抗拉强度的主要方法,但是相关规范没有对加载角度作出限定,导致试验的结果较为离散.为研究加载角度对巴西劈裂试验的影响,利用有限元软件ANSYS建立加载角度为0°的集中加载模型,计算得到的应力数值解与理论解误差较小,证明数值模拟的有效性;之后以集中加载模型为原型分...     

基于云存储的网盘系统架构及关键技术研究

面向企业网或校园网的移动办公与存储的网盘系统有着广泛的市场需求,传统的网盘技术在性能、用户共享、安全性、可扩展性等方面存在诸多缺陷.针对这些不足,本文提出了一种基于云存储的高性能网盘系统架构:采用分布式文件系统MooseFS实现用户数据存储与访问的集群架构:在安全性方面,结合SAMBA实现用户权限管理,用户数据存储支持128 bit AES加密,SSH保证了传输链路的安全;最后,结合用户的实际需求,提供基于Web的访问方式以及客户端的同步盘模式.结果表明,系统在性能、安全性、可扩展性等多方面具有显著优势.     

底栖动物与挺水植物协同修复富营养化水体的研究

通过室外试验探讨中华圆田螺和挺水植物(空心菜、西伯利亚鸢尾)协同修复富营养化水体的效果.结果表明,螺对SS的降解以及挺水植物对TN、TP的去除均有很好的效果.螺的加入会引起TN的升高,但空心菜和螺一组对TN的去除率为37.12％,对TP的去除率为53.49％,短时间对SS的去除率为82.5％;西伯利亚鸢尾和螺对TN的去除率为50.92％,对TP的去除率为32.20％,短时间对SS的去除率为85％.螺能短时间内将悬浮态氮磷转化为溶解态氮磷供植物吸收、利用,由此可见,底栖软体动物和挺水植物对富营养化水体具有明显的净化作用,其协调作用为湖泊富营养化控制提供了可供参考的依据.     

Removal of ammonium ions in wastewater by electrosorption with TiO2 modified graphene electrode

In this study, the TiO₂ modified graphene composite material (RGO/ TiO₂) was prepared by hydrothermal method, and its morphological structure and electrochemical properties were investigated. Then RGO/TiO₂ material was assembled into electrode, and NH₄⁺ ions electrosorption efficiencies of unmodified graphene (RGO) electrode and the RGO/TiO₂ electrode were compared. The effects of applied voltage, circulating velocity and initial concentration on NH₄⁺ ions electrosorption by RGO/TiO₂ electrode were investigated. The characteristics of NH₄⁺ ions electrosorption and the effect of advanced NH₄⁺ ions removal from simulated actual wastewater containing NH₄⁺ ions were also studied. The results showed that the RGO/TiO₂ composite material had a three-dimensional pore structure with specific surface area of 382.08 m²·g^-1 and specific capacitance of 325.80 F·g^-1 at a scan rate of 0.01 V·s^-1, which were better than those of the RGO material. The initial adsorption capacity of RGO/TiO₂ electrode was 28.3% higher than that of RGO electrode. After 10 cycles of regeneration adsorption, the adsorption capacity of NH₄⁺ ions of RGO/TiO₂ electrode only decreased 5.87%, and its cyclic regeneration adsorption property was better than that of RGO electrode. In addition, the applied voltage 2.0 V, circulating velocity 35 ml·min^-1 and initial concentration 1.0 mmol·L^-1 were the optimal NH₄⁺ ions electrosorption conditions for RGO/TiO₂ electrode. The electrosorption process of NH₄⁺ ions by RGO and RGO/TiO₂ electrodes was in accordance with the quasi-first-order kinetic model and the Freundlich isothermal adsorption model. The electrosorption of NH₄⁺ ions was a multi-layer adsorption behavior on heterogeneous surface and physical adsorption was the dominant. When the RGO/TiO₂ electrode was connected in 4-stage series, the removal efficiency of simulated actual NH₄⁺ refining purified water reached 86.84%.     

应用嵌入式系统进行数据采集的研究

本文论述了嵌入式系统相关理论,介绍了开发嵌入式系统的相关软硬件环境,同时根据工业的实际要求,提出了应用嵌入式系统相关技术进行数据采集、展示以及控制的优势、实现的具体方法,并建立了一个实例.     

固化污泥对渗滤液中氟阻滞作用的数值分析

固化污泥是一种新型填埋场底部防渗阻滞材料，为论证其防渗阻滞作用的有效性，需进行典型污染物的穿透试验，但由于固化污泥渗透性很低，采用常规土柱试验很难得到污染物透过其迁移时的相关参数。为解决该问题，用柔性壁渗透试验代替传统土柱试验。渗滤液中污染成分较多，取含量较高且较易穿透的污染物即氟离子作为典型污染物，首先进行穿透试验获得迁移参数，然后结合二维有限元法研究分析其在防渗阻滞层及周边岩土环境中60 a内的运动迁移范围、浓度分布情况，并对比分析未设防渗阻滞层的情况。研究表明，在填埋场底部设置固化污泥防渗层对于以氟为代表的阴性污染物有较好的延迟阻滞作用。由于阳性污染物的穿透能力较阴性污染物弱，因而固化污泥防渗层对重金属等阳性污染物也应具有较强的阻滞作用，从而能进一步延迟填埋场渗滤液对周边环境的污染。