Study on the electronic structure of nickel hydroxide by quantum chemical DV-Xα calculation

The electronic structures of atom clusters NiTO12H12^2＋ and NiTO12H9^- of β-Ni（OH）2 were calculated by quantum chemical DV-Xα method. By analyzing the state densities, orbital populations, net charges and electric charge density differences of the selected clusters, it was indicated that β-Ni（OH）2was not typical ionic crystal, and the bonds between Ni and O atoms had obvious covalent characteristics. The bonds between H atom and other atoms in the crystal structure were weaker, which ensured that H atoms can easily deintercalate and intercalate into β-Ni（OH）2. The structure of β-Ni（OH）2 was not changed by moderate de-intercalation of H atoms. However, with the excessive de-intercalation of H atoms, the structure of β-Ni（OH）2 changed and the electrochemical active properties were reduced.     

A Hierarchical Ensemble Learning Framework for Energy-Efficient Automatic Train Driving

Railway transportation plays an important role in modern society. As China's massive railway transportation network continues to grow in total mileage and operation density, the energy consumption of trains becomes a serious concern. For any given route, the geographic characteristics are known a priori, but the parameters(e.g., loading and marshaling) of trains vary from one trip to another. An extensive analysis of the train operation data suggests that the control gear operation of trains is the most important factor that affects the energy consumption. Such an observation determines that the problem of energy-efficient train driving has to be addressed by considering both the geographic information and the trip parameters. However, the problem is difficult to solve due to its high dimension, nonlinearity, complex constraints, and time-varying characteristics. Faced with these difficulties, we propose an energy-efficient train control framework based on a hierarchical ensemble learning approach. Through hierarchical refinement, we learn prediction models of speed and gear. The learned models can be used to derive optimized driving operations under real-time requirements. This study uses random forest and bagging – REPTree as classification algorithm and regression algorithm, respectively. We conduct an extensive study on the potential of bagging, decision trees, random forest, and feature selection to design an effective hierarchical ensemble learning framework. The proposed framework was testified through simulation. The average energy consumption of the proposed method is over 7% lower than that of human drivers.     

一个三维Sierpinski块的Hausdorff测度

研究了三维Ｓｉｅｒｐｉｎｋｉ块的Ｈａｕｓｄｏｒｆｆ测度,通过构造质量分布函数,运用质量分布原理获得了一个三维Ｓｉｅｐｉｎｓｋｉ志的Ｈａｕｓｄｏｒｆｆ测度的准确值。     

Effect of intermittent aeration on the treatment performance in a submerged membrane bioreactor

In order to improve removal for nitrogen in a pilot-scale submerged membrane bioreactor (SMBR), intermittent aeration was conducted, and the effect on the treatment performance under four kinds of operation condition (run 1, continuous aeration; run 2, 60/60 min aeration on/off time; run 3, 60/90 min aeration on/off time; run 4, 60/75 min aeration on/off time) was evaluated. The results showed that depending on the specific on/off of the aeration time ratio, removal efficiency of nitrogen could be improved significantly, and the removal rates of total nitrogen (TN) under different operation conditions were 28.0%, 59.5%, 66.8% and 70.7%, respectively. There were no obvious differences for removal rates for COD_Cr and ammonia among different operation conditions. In general, intermittent aeration could be used as a feasible way to improve treatment performance for nitrogen in the SMBR.     

非线性参数拟合问题的改进阻尼最小二乘方法和共轭梯度方法

本文首先给出了一个改进的阻尼最小二乘方法,并把它用于非线性曲线拟合问题。由于A~TA为对称正定的就有理由一开始把法方程组做乔累斯基分解,并使法方程的条件数有所改善,为此目的而引入了一个非负的阻尼因子。 对于共轭梯度方法,由于非线性函数在极小点附近表现为二次函数的特性,所以在非线性拟合问题中引入了共轭关系P_j~TAP_j=0共轭梯度方法的优点是收敛速度较快,当它用于二次函数极小化问题时总是在有限步内收敛。     

M型锶钙铁氧体的研究

Ｃａ离子在Ｍ型锶钙六角铁氧体中的最大固溶量Ｘｍ≈０．５。在固溶范围内，Ｃａ离子代换Ｓｒ离子对材料的本征磁性能如居里温度θｆ，比饱和磁化强度δｓ，以及磁晶各向异性场ＨＡ没有明显的影响，这有可能在保证材料性能不下降的前提下，在Ｍ型锶钙六角铁氧体中加入廉价的钙来降低材料成本。     

迪斯尼跨文化管理的启示

伴随着世界经济一体化进程的不断发展,世界范围内跨文化的经济合作日益频繁,由文化差异给企业带来的碰撞和冲突日益彰显突出。本文通过对迪斯尼在日本和法国的跨国经营成败的分析,指出文化差异对跨国经营的一系列影响,同时对跨国企业应怎样做好市场调研、进行跨文化管理以及如何利用文化差异获得竞争优势进行了阐述。     

高职院校建立学科信息共享空间的途径探索

针对高职院校和高职院校图书馆的特点,本文认为建立学科信息共享空间是创新性的服务方式,是深化参考咨询服务的有效途径。为了避免盲目跟风建设、缺少实用性等问题出现,高职院校图书馆学科信息共享空间不同于电子阅览室的建设,需要发挥图书馆和院系各自的优势,在图书馆建立学科阅览室的同时,在院系建立学科服务基地,共同开展学科服务。     

Blurred Defocused Image Restoration Based on FRFT

A technique for restoring the blurred image resulted from defocusing of the lens is proposed in this paper, which is based on fractional Fourier transform （FRFT）.The FRFT, as a powerful tool for the analysis of time-varying signals, is closely connected with the optical imaging system. FRFT also can describe optical imaging process just like Fresnel diffractions, so a defocused imaging model based on FRFT is established to explain the blur phenomena of defocusing image. The defocused imaging model is greatly different from the traditional point spread function （PSF） model, and enables to uncover the blur nature of non-focus image. Then, an image restoration method using the novel model is proposed to handle the blurred defocused image. The method adopted a new iterative phase retrieval approach which can approximately estimate phase signals from intensity signals of a single defocused image by means of FRFT. Restoring image may acquire sharp image by implementing inverse FRFT on complex image signal made from the estimated phase signals and intensity signals. Experimental results demonstrate that the method is effective in restoring blurred defocused image.