一种有限时段Markov决策过程的强化学习算法

研究有限时段非平稳的Markov决策过程的强化学习算法。通过引入一个人工吸收状态，把有限时段问题变为无限时段问题，从而可利用通常的强化学习方法来求解。在文献[3]提出的算法思想基础上，提出了一种新的有限时段非平稳的Markov决策过程的强化学习算法，并用无完全模型的库存控制问题进行了实验。     

汽轮机发电机组动静碰摩故障的诊断与处理

文章介绍了汽轮发电机组产生动静碰摩的原因,以及碰摩振动发生、发展的机理,总结了碰摩振动响应的频谱特征,给出了现场故障诊断要点。同时从理论、实验研究和现场振动故障诊断处理等方面,对近些年来国内外,特别是国内在这方面的主要研究成果与经验进行了简要总结与评述。通过对导致动静碰摩的各类原因分析,对防止碰摩及振动的措施作了一些有益的探讨。     

三相单开关零电流Cuk型功率因数校正器的研究

提出了一种新颖的三相Cuk型高功率因数校正电路。在电路拓扑中采用三相全桥整流桥和单管功率开关实现高功率因数和低谐波电流输入；同时在中间储能电容(过渡电容)上串联一电感以及在续流二极管上并联一小电容，使得电路工作在复合谐振状态，从而获得零电流开关。文章分析了电路的工作原理，仿真验证了理论分析结果，同时一个2kW的试验电路验证了结论的正确性。该电路具有输出电压调节范围宽、功率因数和效率高等特点，具有很好的实用化前景。     

引线框架用铜合金C194的组织性能研究

通过对国内某A企业和德国威兰德公司C194合金铜带的析出物颗粒分析，发现A企业的C194合金的主要析出物有α—Fe和Fe3P，而威兰德公司的C194合金的主要析出物为α—Fe，α—Fe是C194合金的强化相。由于P显著降低材料的导电、导热性能，对材料综合性能不利，因此在实际生产中应严格控制P的含量，尽量取下限。     

高效液相色谱手性固定相研究进展

对近年来高效液相色谱手性固定相的研究进行了综述。重点介绍了手性固定相的分类、拆分机理和应用的新进展。讨论了各类手性固定相优缺点，提出了目前存在的问题、今后的研究方向和重点。     

A new instrument for passive remote sensing: 2. Measurement of leaf and canopy reflectance changes at 531 nm and their relationship with photosynthesis and chlorophyll fluorescence

A previously described passive remote sensing fluorimeter (see companion paper) was modified to detect changes in the reflectance of vegetation. The utility of this remote sensing technique to measure the Physiological Reflectance Index (PRI) is shown at both leaf level under laboratory conditions and at the canopy level in the field. PRI, defined as the relative changes in reflectance at 531 nm with respect to those at 570 nm (PRI=R531−R570/R531+R570), is related to xanthophyll-related, dynamic changes of non-photochemical quenching of chlorophyll fluorescence. The robustness of this relationship by simultaneous remote sensing of PRI and chlorophyll fluorescence is strengthened. At the leaf level, the existence of two kinetically distinct components of PRI is shown. A fast (within seconds) component that is partly attributed to ΔpH induced chloroplast shrinkage, and a slow (within minutes), main component that is related to xanthophyll de-epoxidation, as demonstrated by its disappearance in the presence of DTT. Overall, PRI correlated better with non-photochemical quenching of chlorophyll fluorescence (NPQ) than with any other measured parameter, including the photochemical efficiency of PSII. Finally, at the canopy level and under field conditions, it is shown that PRI can be a useful tool for remote sensing of water stress in grapevines.     

A Statistical Control Chart for Stationary Process Data

In the statistical process control environment, a primary method to deal with autocorrelated data is the use of a residual chart. Although this methodology has the advantage that it can be applied to any autocorrelated data, it needs some modeling effort in practice. In addition, the detection capability of the residual chart is not always great. This article proposes a statistical control chart for stationary process data. It is simple to implement, and no modeling effort is required. Comparisons are made among the proposed chart, the residual chart, and other charts. When the process autocorrelation is not very strong and the mean changes are not large, the new chart performs better than the residual chart and the other charts.     

A short guide to topological terms in the effective theories of condensed matter

Abstract

This article is meant as a gentle introduction to the topological terms that often play a decisive role in effective theories describing topological quantum effects in condensed matter systems. We first take up several prominent examples, mainly from the area of quantum magnetism and superfluids/superconductors. We then briefly discuss how these ideas are now finding incarnations in the studies of symmetry-protected topological phases, which are in a sense a generalization of the concept of topological insulators to a wider range of materials, including magnets and cold atoms.     

Influence of Mo doping on the tribological behavior of Ti3AlC2 ceramic at different temperatures

(Ti_0·8Mo_0.2)₃AlC₂ solid solutions were successfully synthesized from Ti, Al, TiC, and Mo powders using the in situ hot-pressing sintering method. The tribological properties of (Ti_0·8Mo_0.2)₃AlC₂ and the reference Ti₃AlC₂ in the temperature range 25–800 °C were evaluated in ambient air with the counterpart of Al₂O₃ balls. The results show that (Ti_0·8Mo_0.2)₃AlC₂ has improved lubricating properties and wear resistance above 400 °C compared with Ti₃AlC₂. This can be contributed to the formation of tribo-oxidation films containing MoO₃ and MoO_3-x. Structural characterization of the tribo-oxidation films was conducted using SEM, EDS, Raman spectroscopy, and XPS to evaluate the effect of Mo doping on the wear mechanisms of Ti₃AlC₂ in detail.     

Frequency and phase estimation in time series with quasi periodic components

In this article, we consider frequency and phase estimation in a noisy oscillation with potentially non‐constant phase increments resulting from an underlying non‐constant frequency. A maximum periodogram method on segments is used to estimate the time‐varying frequency and a subsequent least squares approach to estimate the phase. A key problem addressed in this article is the question how to set up a meaningful concept of asymptotic statistics for this model. This problem is solved by a special infill asymptotics concept. We use this concept to prove consistency and asymptotic normality of the estimates. Furthermore, the phase estimate is compared to the Hilbert transform in a simulation.