某取排水车180°铰接式弯管优化分析

为了解决新型铰接式弯管的变形问题,利用ANSYS软件对铰接式弯管进行建模和流固耦合分析,发现原始弯管两侧中部内凹、弯径增大、最大应力超过许用应力,据此提出了导流器错位排布方案.结果 表明:采用方案三错位排布导流器方案、将导流器间距设为70 mm时得到最优方案,优化后的弯管4最大应力由178.12 MPa降低到92.4 MPa、降低了52％,弯管12最大应力由289.52 MPa降低到135.4 MPa、降低了47％,取得了较好的优化效果,为180°弯管导流器设计提供了一种新方案.     

刚性航天器的预定义时间滑模控制

针对刚性航天器在姿态跟踪控制中存在的系统不确定及外界干扰等问题,提出了一种预定义时间滑模控制器(PTSMC).首先,给出了以四元数为姿态参数的航天器姿态跟踪控制系统,利用误差四元数和误差角速度设计了预定义时间滑模面.然后,考虑了航天器系统的不确定性和外界干扰设计了一种非保守上界的PTSMC,并通过边界层技术降低了系统抖动.最后,通过设计Lyapunov函数,证明了所提出的控制器的预定义时间稳定性和系统收敛时间上界的非保守性.仿真结果表明,刚性航天器的姿态跟踪误差精度可达1.5×10-6 rad,角速度跟踪误差精度可达2×10-6 rad/s.与现有的预定义时间控制器相比,所提出的控制器的稳定时间上限是更加非保守的,与传统PD控制和非奇异终端滑模控制相比,所提出的控制器具有更高的跟踪精度和鲁棒性.通过3自由度气浮平台的姿态跟踪实验进一步说明了控制方案的有效性,其中角度跟踪误差小于0.1 rad,位置跟踪误差小于0.2 m.     

Spectral radiance reconstruction from trichromatic camera responses based on orthogonal test and regularized algorithm

Reconstruction of spectral information based on multi‐channel image system is a significant problem in color reproduction, detection, and recognition. A spectral radiance reconstruction from trichromatic digital camera responses is researched in this article. The mapping relationship between the trichromatic imaging system response and the incident spectral radiance is analyzed. Then, in order to remove the ill‐posedness of the problem, a regularized constraint solution model of spectral radiance reconstruction matrix is established. And the spectral radiance can be reconstructed by spectral radiance reconstruction matrices and trichromatic imaging system response. Finally, the spectral radiance reconstruction matrix is estimated by the system radiometric calibration experiment. The input radiance is offered by a LCD display. A 3‐factor and 9‐level orthogonal test is designed for the calibration experiment, and a test set of 24 colors is used for precision analysis. The results show that the average relative mean error of our method is 8.69%, it is lower than that of Wiener filtering method by 2.84%. The method can reconstruct spectral radiance information effectively.     

1000MW燃煤机组工业废水零排放改造中脱水机的调试优化运行研究

以华能某2×1000 MW燃煤机组为例,对全厂原有工业废水处理系统进行升级改造,从而实现工业废水系统持续稳定运行.改造的重点在于脱水机的调试运行,实现脱水机在满足工业废水系统出力要求的基础上,连续稳定地产出合格的回用水和污泥.     

不同盐沼湿地类型脱氮除磷效能及影响因素分析

采用沉水植物表面流湿地(沉水组)、挺水植物表面流湿地(挺水组)和浮床湿地(浮床组)3种盐沼湿地对长江口近岸低污染水体进行脱氮除磷效能的研究。结果表明,HRT为3 d时,水组、挺水组、浮床组对NO3^--N的去除率在高温时段分别为79.9%±13.2%、71.8%±15.2%、77.2%±13.2%,中温时段分别为39.4%±13.7%、31.5%±8.5%、18.4%±16.6%,低温时段分别为15.6%±14.6%、19.7%±8.6%、2.%5±8.6%。沉水组和挺水组对TP的去除率受温度影响较小,分别为66.4%±32.4%、55.5%±29.4%;而浮床组除磷效果受温度影响较大。当HRT缩短为1.5 d时,3组湿地系统在高温时段仍可达到相近的脱氮除磷效果,在中低温时段脱氮除磷效果都有不同程度的下降。     

高熵形状记忆合金的研究进展

高熵形状记忆合金是在等原子比NiTi合金的基础上,结合高熵合金的概念,逐渐发展起来的一种新型高温形状记忆合金。近年来,已开发出了综合性能优异的(TiZrHf)50(NiCoCu)50系和(TiZrHf)50(NiCuPd)50系高熵形状记忆合金,引起了广泛的关注和研究兴趣。本文从物相组成、微观组织、马氏体相变行为、形状记忆效应和超弹性等角度出发,综述了高熵形状记忆合金的研究进展,并对高熵形状记忆合金未来的研究重点进行了展望。     

Phase constitution,microstructure and mechanical properties of a Ni-based superalloy specially designed for additive manufacturing

In this study, a kind of Ni-based superalloy specially designed for additive manufacturing (AM) was investigated. Thermo-Calc simulation and differential scanning calorimetry (DSC) analysis were used to determine phases and their transformation temperature. Experimental specimens were prepared by laser metal deposition (LMD) and traditional casting method. Microstructure, phase constitution and mechanical properties of the alloy were characterized by scanning electron microscopy (SEM), transmission scanning electron microscopy (TEM), X-ray diffraction (XRD) and tensile tests. The results show that this alloy contains two basic phases, γ/γ', in addition to these phases, at least two secondary phases may be present, such as MC carbides and Laves phases. Furthermore, the as-deposited alloy has finer dendrite, its mean primary dendrite arm space (PDAS) is about 30-45 μm, and the average size of γ' particles is 100-150 nm. However, the dendrite size of the as-cast alloy is much larger and its PDAS is 300-500 μm with secondary and even third dendrite arms. Correspondingly, the alloy displays different tensile behavior with different processing methods, and the as-deposited specimen shows better ultimate tensile stress (1,085.7±51.7 MPa), yield stress (697±19.5 MPa) and elongation (25.8%±2.2%) than that of the as-cast specimen. The differences in mechanical properties of the alloy are due to the different morphology and size of dendrites, γ', and Laves phase, and the segregation of elements, etc. Such important information would be helpful for alloy application as well as new alloy development.     

主存高效的公交网络路径规划索引

在公交时间表下给定起始和目标站点,路径规划查询返回一组到达时间早和换乘次数少的帕雷托最优路径.现有的索引方法需要大量运行时内存.本文提出主存空间高效的索引方法(a-)PAINT.(a-)PAINT对每个站点v预计算一组标签,使得对于从站点s到站点d的查询可以通过匹配s和d相关的标签高效地生成查询结果的一条路径.PAINT对任意查询返回最优路径.a-PAINT只需要很小的预处理开销,但可能返回多一趟换乘的次优路径.用真实的公交时间表与模拟查询测试,PAINT具有合理的预处理开销.a-PAINT需要更少量的预处理开销,在大规模公交网络下准确率达90％.     

开关柜小车"几"字型操作手柄的研制与应用

本文针对电力系统的变电站停送电操作过程中使用的传统开关柜小车操作手柄所遇到的问题进行了分析与研究,包括绝缘手套易黏连、摇柄易脱落等,并研制了一种开关柜小车"几"字型操作手柄.该手柄已在多处现场实践应用,效果良好,大大提升了运维操作的安全可靠性,提高了工作质量和效率,在保障电力系统安全稳定运行的同时,创造了丰厚的生产经济效益.