光栅衍射缝间干涉因子次极大强度对称性的菲涅耳半波带法证明

本文用菲涅耳半波带法推导出了一个非常有用的次极大位置公式,将该位置公式和振幅矢量法求出的次极大位置结合起来,方便地求出了缝间干涉因子的次极大的强度,证明了缝向干涉因子的次极大强度具有对称性。避免了对振幅矢量法求次极大位置这个方程的直接求解,因为用该方法求出的次极大强度与理论值完全符合,说明菲涅耳半波带法不但可以用来分析单缝衍射,同时还完全能够用来分析光栅衍射。     

Preparation of Mo2C by MPCVD and Its Photocatalytic Properties

Mo2C was prepared by microwave plasma chemical vapor deposition(MPCVD)technique with the power of 800 W and pressure of 18 kPa. Compared with traditional prepar...     

Effects of Tearing Conditions on the Crack Propagation in a Monolayer Graphene Sheet

The path of crack propagation in a graphene sheet is significant for graphene patterning via the tearing approach. In this study, we evaluate the fracture properties of pre-cracked graphene during the tearing process, with consideration of the effects of the aspect ratio, loading speed, loading direction, and ambient temperatures on the crack propagation in the monolayer sheet. Some remarkable conclusions are drawn based on the molecular dynamic simulation results, i.e., a higher loading speed may result in a complicated path of crack propagation, and the propagation of an armchair crack may be accompanied by sp carbon links at high temperatures. The reason for this is that the stronger thermal vibration reduces the load stress difference near the crack tip and, therefore, the crack tip can pass through the sp link. A crack propagates more easily along the zigzag direction than along the armchair direction. The out-of-plane tearing is more suitable than the in-plane tearing for graphene patterning. The path of crack propagation can be adjusted by changing the loading direction, e.g., a rectangular graphene ribbon can be produced by oblique tearing. This new understanding will benefit the application of graphene patterning via the tearing approach.     

A deep-learning-based prediction method of the estimated ultimate recovery(EUR)of shale gas wells

The estimated ultimate recovery(EUR)of shale gas wells is influenced by many factors,and the accurate prediction still faces certain challenges.As an artificial...     

株溪口电站土石围堰控制性灌浆施工工艺

在水利水电工程中,围堰的防渗效果对工程主体的施工进度和经济效益影响相当大．控制性灌浆是围堰堵漏防渗的重要方法之一。文章就株溪口水电站一期围堰控制性灌浆的施工工艺进行分析,其施工方法可供相同施工条件的围堰进行参考。     

Determination of the embedded electronic states at nanoscale interface via surface-sensitive photoemission spectroscopy

The fabrication of small-scale electronics usually involves the integration of different functional materials. The electronic states at the nanoscale interface ...     

Molecular dynamics study on nanotube-resonators with mass migration applicable to both frequency-tuner and data-storage-media

We investigated the cantilevered carbon-nanotube-resonator including electromigratively movable nanoparticle via classical molecular dynamics simulations and continuum model. The change of the effective mass value, which was closely correlated with the position change of the encapsulated nanoparticle, could be regressed by a power function, the resonance frequency of the carbon-nanotube-resonator could be tuned by controlling the nanoparticle’s position, and the possible frequency-shift-ranges then reached 18–85%. The suggested device could be served as a data-storage-media for electromechanical nonvolatile-memory as well as a frequency-tuner.     

Degenerate problems of optimal control. II

The paper is the second part of the review of the results obtained by the special theory of the degenerate problems of optimal control and its applications, including the newest ones. Consideration was given to the methods based on the rearrangement of the degenerate problems in the smaller-order regular derivative problems, the main types of solutions of the derivative problems, and the issues of their realization as the generalized solutions of the original problems. The generalized conditions for their optimality were derived. Examples, both methodological and applied, were presented to demonstrate the efficiency of these methods.     

耦合渐变槽线天线及其和差波束的矩量法分析

本文阐述一种新型渐变槽线天线（ＴＳＡ）结构,耦合渐变槽线天线ＣＴＳＡ。单片的ＣＴＳＡ除可降低副瓣电平,提高增益,改善Ｅ面Ｈ面波束的对称外,还可通过与之配合的平面印刷奇偶模双工器馈电,同时实现和差波束。本文应用空间域矩量法（ＭｏＭ）建立了分析各种ＴＳＡ结构的数值模型;该方法在没有介质基片的情况下是严重的,本文集中讨论简化ＭｏＭ中阻抗矩阵积分运算的各种技术,有效地减小了计算量,并获得较高的精度。计算结