快中子零功率反应堆(DF-VI)的临界事故概率分析

本文应用故障树分析方法,对快中子零功率堆(DF-Ⅵ)在启动过程中发生临界事故的可能性做了初步的定量估计。结果表明,该堆每次启动发生临界事故的概率约为10~(-6)量级,得出确保装置启动安全的首要因素是选配合格的操作人员的结论,并对设备的改进提出了一些建议.     

基于无线通信技术的FFU风机群控系统

针对大型洁净工程实现自动化控制的需要,利用数字无线通信技术,设计了一种新型网络化的多风机过滤器单元(FFU)群控系统,详细介绍了系统的组成实现原理和软硬件设计方法;系统间采用基于射频收发芯片nRF2401实现数据的无线收发,有效地减少了系统布线和设计成本,提高了系统的组网灵活性和适用性;对设计开发的系统进行了测试实验,实验结果表明该系统数据通信正确可靠,系统具有结构简单、组网灵活、监控效果好和可扩展性强等优点。     

水工隧洞地震作用计算模型的适用性研究

针对水工隧洞在地震作用下的计算问题,对水工隧洞地震作用计算模型进行了计算对比和适用性研究。分析常用的4种计算模型用于计算水工隧洞地震作用的可行性,通过理论和数值计算确定"径向和切向反力弹簧模型"的计算参数,研究了地震作用下隧洞上方计算土体对隧洞衬砌的作用方式。结合试验验证,该方法和数值计算对比的结果表明:围岩的法向和切向弹性抗力系数受隧洞埋深、围岩类型和衬砌不同部位的影响,随埋深的增加先增大,然后趋于一个定值,围岩条件越好,数值越大,在隧洞两侧部位的数值较大;在地震作用下,隧洞上方计算土体以切向力的方式作用在隧洞衬砌的上半部分,可以通过将隧洞上部计算土体分条后进行计算。该方法可充分考虑地震对隧洞的动力和约束作用,适用于水工隧洞抗震计算。     

脂肪酸甲酯处理含苯胺工业废水

采用正交实验设计研究了用脂肪酸甲酯处理工业苯胺废水的条件。实验表明:在影响苯胺废水萃取效果的诸因素中,影响大小的顺序为pH值、油水相比、溶液初始浓度和温度。在pH值=7,油水相比为2∶1,20℃的最佳萃取条件下,高浓度苯胺废水经萃取剂脂肪酸甲酯三级萃取后,苯胺去除率达99.98%。     

汉语复句信息处理研究二十年

加强汉语复句信息处理研究对中文信息处理具有重要意义。该文介绍了汉语复句信息工程的概况,将复句知识建模、关系标记识别、非分句识别、复句句法语义关系判定、复句知识库建设等成果条理化,结合已有成果的研究视角、方法及关注焦点来分析复句信息处理的研究现状,并对其发展趋势进行了展望。     

Non-Hierarchical Architected Materials with Extreme Stiffness and Strength

Stretch-dominated truss and plate microstructures are contenders in the quest for realizing architected materials with extreme stiffness and strength. In the low volume fraction limit, closed-cell isotropic plate microstructures meet theoretical upper bounds on stiffness but have low buckling strength, whereas open-cell truss microstructures have high buckling strength at the cost of significantly reduced stiffness. At finite volume fractions, the picture becomes less clear but both are outperformed by hollow truss lattice and hierarchical microstructures in terms of buckling strength. Despite significant advances in manufacturing methods, hollow and multi-scale hierarchical microstructures are still challenging to build. The question is if there exist realizable microstructures providing stiffness and strength matching or even beating hard-to-realize hollow or hierarchical microstructures? Herein, single-scale non-hierarchical (first order) microstructures that beat the buckling strength of hollow truss lattice structures by a factor of 2.4 and first- and second-order plate microstructures by factors of 5 and 1.4, respectively, are systematically designed, built, and tested. Stiffness of the microstructures is within 40% of theoretical bounds and beats both truss and second order plate microstructures. The microstructures are realized with 3D printing. Experiments validate theoretical predictions and additional insight is provided through numerical modeling of a CT-scanned sample.     

On projection methods,convergence and robust formulations in topology optimization

Mesh convergence and manufacturability of topology optimized designs have previously mainly been assured using density or sensitivity based filtering techniques. The drawback of these techniques has been gray transition regions between solid and void parts, but this problem has recently been alleviated using various projection methods. In this paper we show that simple projection methods do not ensure local mesh-convergence and propose a modified robust topology optimization formulation based on erosion, intermediate and dilation projections that ensures both global and local mesh-convergence.     

机械零件三维建模与工程分析一体化设计方法

机械零件结构设计与工程分析一般不能在同一环境下进行,因而造成文件转换繁琐、设计效率低等问题.提出了在Solid Works环境下,解决这一问题的方法.按照零件三维建模,利用Solid Works的有限元分析功能对零件进行应力、应变、疲劳等分析,并动态、可视化地呈现出变形情况、各个节点的应力数值、安全系数等数字信息,并依此对零件进行结构修改,优化设计的思路,实现了机械零件结构设计与工程分析的一体化和数字化.     

Modeling of an industrial scale hydrodynamic cavitation multiphase reactor for Prileschajew epoxidation

The hydrodynamic cavitation multiphase reactor (HCMR) is emerging as a promising alternative for the intensification of liquid–liquid heterogeneous reactions, but research on HCMR modeling is lacking. In this article, an HCMR model was developed using Prileschajew epoxidation as the model system. First, based on experimental measurements of oil/water two-phase flow downstream of hydrodynamic cavitation devices, semiempirical correlations were proposed to describe the droplet size and droplet size distribution (DSD) as functions of flow conditions and geometry parameters. Then, with boundary conditions calculated by the DSD correlation, a droplet dynamics simulation in a reaction tank was performed by computational fluid dynamics coupled with population balance model to obtain the two-phase interfacial area. Finally, the acquired reactor model was substituted into an overall kinetic model, to simulate the epoxidation reaction in HCMR. Model predictions were verified by experimental results measured on an industrial scale HCMR.     

澳大利亚某锂辉石矿预先脱泥——浮选试验研究

澳大利亚某进口锂辉石矿含有较多的矿泥,对浮选作业产生不利影响,试验采用水力沉降法、浮选法等不同方法对锂辉石矿进行预先脱泥,考察了不同方法的脱泥效果及对后续锂辉石浮选的影响。研究发现以十二烷基硫酸钠作为浮选药剂对锂辉石矿进行浮选脱泥取得了最佳的脱泥效果,脱除的矿泥量大、含锂品位低、矿泥中锂的损失小,脱泥后再浮选锂辉石,获得的锂辉石粗精矿品位有了很大程度的提高。预先脱泥后的锂辉石矿经过一次粗选两次精选三次扫选的浮选流程,可获得良好的选矿指标。闭路试验表明,该进口锂辉石矿原矿Li_2O含量为1.42%,经预先脱泥—浮选锂辉石选别流程处理后,获得的锂辉石精矿Li_2O品位为5.83%,Li_2O回收率为78.54%。