基于586-Driver的无人机飞控计算机智能检测系统研制

传统飞控计算机检测方法以人工操作为主,存在一定的主观性且效率低下的缺点。采用信号门限检测技术,设计了飞控计算机一键式全功能检测方案。以586-Driver板卡为核心,设计了智能检测系统,实现了在全程无人干预情况下对飞控计算机按预设时序逻辑的自动检测。通过系统测试表明：满足某型飞控计算机的检测需求,提高了飞控计算机检测效率,具有实际工程应用价值。     

Electro-optic polymer assisted optical switch based on silicon slot structure

One kind of electro-optic polymer assisted Mach-Zehnder optical switch based on silicon slot structure is presented in this paper. The interference arms of the switch are slot structures instead of regular single-mode waveguides. By filling electro-optic material in the void slot of the arms, direct electro-optic modulation can be introduced. Theoretical model and detailed analysis are given in this paper. The length-independent product V_πL is about 74 mV cm when slot width is 100 nm, and 37 mV cm when slot width is 50 nm, when the polymer with a electro-optical coefficient of γ₃₃ = 130 pm/V is assisted. An ultralow energy consumption of only 37 fJ/bit is achievable, and the turn-on time of the switch is less than 1.5 ps.     

Direct measurement of the surface dynamics of supercooled liquid-glycerol by optical scanning a film

The surface dynamics of supercooled liquid-glycerol is studied by scanning the thickness of the glycerol film with single photon detection. Measurements are performed at room temperature well above the glycerol's glass transition temperature. It is shown that the surface dynamics of the glycerol film is very sensitive to the temperature. The linear relationship between the thickness of the film and the viscosity predicted by the Vogel--Fulcher--Tammann--Hesse (VFTH) law is also presented experimentally.     

Upper Critical Fields and Anisotropy of BaFe1.9Ni0.1As2 Single Crystals

Temperature dependence of the upper critical magnetic field （Hc2） near Tc of 20 K in a BaFe1.9 Ni0.1 As2 single crystal is determined via magneto-resistance measurements, for the out-plane （H ⊥ab） and in-plane （H ｜｜ ab） directions in magnetic fields of up to 8 T. The upper critical fields at zero temperature estimated by the Werthamer-Helfand- Hohenberg （WHH） formula are μ0H^｜｜ c2（0） = 137 T and μ0H⊥c2（0） = 51 T, both exceeding the weak-coupling Pauli paramagnetic limit （μ0Hp = 1.84Tc）. However, the WHH formula could overestimate the μ0H^｜｜12（0） value. The anisotropy of upper critical fields is around 3 in the temperature range close to Tc. The result is very similar to the Co-doped 122 superconductor BaFe2-x Cox As2, indicating that electron-doped 122 superconductors exhibit similar superconducting properties.     

基于XGBOOST的恒星光谱分类特征数值化

恒星光谱分类是研究恒星的基础性工作之一,常用的光谱分类是基于20世纪70年代Morgan和Keenan建立起来的并逐步完善的MK分类系统。然而基于MK规则的交互式决策分类系统对处理海量天文光谱数据存在着一定的困难。目前光谱巡天一般采用的自动化分类则是模版匹配方法而忽略对谱线特征的测量。怎样自动、客观地提取海量光谱中的分类特征并应用这些特征进行分类可以对天体的物理化学性质的统计分析至关重要。针对此问题,通过机器学习和计算光谱的谱线指数结合的方法,提取光谱特征,并通过大数据分析定量地确定对光谱特征谱线的分类判据（数值化）,确定每一类光谱具有物理意义的特征谱线的强度分布。首先对LAMOST DR4恒星光谱测量其谱线指数作为输入,光谱的分类标记采用官方发布的分类结果。使用XGBoost算法进行自动分类及特征排序,从而获得已知或未知的对于分类决策最为敏感的谱线。首先,选取高信噪比（S/N>30）、被LAMOST标记为B,A,F和M的恒星光谱数据,总计约414万个。然后,对光谱数据计算谱线指数从而使其得到降维处理,过滤冗余信息。其次,将处理后的恒星光谱数据随机划分为训练集和测试集,通过适当调整算法参数,用训练集得到所需要的分类决策树模型,用测试集测试其稳定性和可用性,以防止出现过拟合,同时使用算法自带函数进行提取分类特征。最后,输出并整理实验中算法所得的决策树模型,并挑选其概率比较大的分支作为最终的决策树模型。通过实验,可以发现在固定参数下,XGBoost所得的模型有一定的自适应性,较少受数据集影响,总体准确率可达88.5%;同时其所输出的分类决策树与已知的特征较为吻合,而且可以获得基于大数据的、数值化的特征谱线对应分类的范围,为完善基于特征的分类提供定量的规则。     

Coupling effects of depletion interactions in a three-sphere colloidal system

In a three-sphere system, the middle sphere is acted upon by two opposite depletion forces from the other two spheres. It is found that, in this system, the two depletion forces are coupled with each other and result in a strengthened depletion force. So the difference of the depletion forces of the three-sphere system and its corresponding two two-sphere systems is introduced to describe the coupling effect of the depletion interactions. The numerical results obtained by Monte-Carlo simulations show that this coupling effect is affected by both the concentration of small spheres and the geometrical confinement. Meanwhile, it is also found that the mechanisms of the coupling effect and the effect on the depletion force from the geometry factor are the same.     

Plasmonic planar lens based on stack of metal–insulator–metal waveguides with height tuning

We introduce a technique capable of focusing electromagnetic (EM) waves through plasmonic nanoslits symmetrically arranged along the indented semi-circular surface in silver background. The EM transports through the tuning slits in the form of surface plasmon polaritons (SPPs), and gets the required phase retardations to focus at the focal plane. Due to the subwavelength nature of planar metallic lens, we present the rigorous electromagnetic analysis by using two dimensional (2D) finite difference time domain (FDTD) method. These height-modulated slits with uniform width are demonstrated to have unique advantages in beam manipulation. In combination with previous studies, it is expected that our structure with small number of slits could lead to realization of optimum designs of plasmonic nano-lens.     

Magnetic properties in zinc-blende CdS induced by Cd vacancies

The magnetic property induced by neutral Cd and S vacancies in CdS bulk and thin film are investigated, using first principles simulation. For bulk CdS, the magnetism originates from Cd, instead of S, vacancies. The ferromagnetism with a Curie temperature above room temperature can be expected. For CdS thin film, both Cd and S vacancies does not yield any magnetism at the (111) surface, while local magnetic moments at the outermost S plane of the (001) surface is ascribed to the surface effect. The ferromagnetism at S-terminated (001) surface can account for the experimental observation.     

A jump diffusion model for spot electricity prices and market price of risk

We construct a jump-diffusion model with seasonality, mean-reversion, time-dependent jump intensity and heteroskedastic disturbance for electricity spot prices, while keeping the analytical tractability of futures prices. We find that the jump component plays a considerably larger role than the diffusion component in the variance of spot prices. Moreover, the jump intensity is much higher during summer and winter. We also explore the seasonal market price of risk (MPR) with different maturities, from one month to five months. Our results show that the diffusion risk and the jump risk are priced quite differently.     

Opinion dynamics in networked command and control organizations

An opinion dynamics model for a Command and Control (C2) organization is essential for simulating combat system effectiveness. However, few studies have addressed opinion evolution in C2 simulation. With the goal of overcoming this research gap, this paper proposes an opinion exchange model, which is illustrated through a practical example of an Armored Division network. The model is divided into homogeneous and heterogeneous aspects: the former is mainly characterized by communication rules and types, while the latter is extended with the influence of multi-level opinion leaders. After carrying out the simulation of the two main models, the results show that the opinion evolution of the hierarchical leveled C2 organization with descending influence is much more complex and unpredictable than that of social networks.