基于图像特征检测和匹配的无人船航行姿态角提取方法

计算机视觉的飞速发展, 使得采用视觉技术辅助无人船航行成为可能. 在无人船巡航过程中, 获取船体航向是航行控制的必备基础. 特征匹配是无人船相关视觉技术中的重要部分, 是目标识别和定位等功能的关键步骤. 获取无人船运动姿态的基本步骤是对图像前后帧进行有效的特征提取和匹配. 针对水域环境中的图像静态特征提取速度慢、精度低的问题, 本文提出一种图像匹配方法以求取无人船的航行姿态角. 首先对图像预处理, 并对有效区域进行特征提取. 其次, 设计一种基于描述子相似度的初始特征匹配策略. 再其次, 筛选特征匹配对, 优化模型参数. 最后, 通过前后帧旋转矩阵计算航行姿态角. 实验表明, 该方法能有效提取无人船的航行姿态角.     

Finite groups with a given number of relative centralizers

We will study all finite groups and their subgroups with at most four relative centralizers.     

Relative deprivation as a cause of risky behaviors

ABSTRACT

Combining a standard measure of concern about low relative wealth and a standard measure of relative risk aversion leads to a novel explanation of variation in risk-taking behavior identified and documented by social psychologists and economists. We obtain two results: (1) Holding individual i’s wealth and his rank in the wealth distribution constant, the individual’s relative risk aversion decreases when he becomes more relatively deprived as a result of an increase in the average wealth of the individuals who are wealthier than he is. (2) If relative deprivation enters the individual’s utility function approximately linearly then, holding constant individual i’s wealth and the average wealth of the individuals who are wealthier than he is, the individual’s relative risk aversion decreases when he becomes more relatively deprived as a result of a decline in his rank. Our findings provide a theoretical support for evidence about the propensity of relatively deprived individuals to gamble and resort to other risky behaviors.     

某型机进近段高精度相对姿态实时测量技术

某型机在飞行训练过程中，进近段的二维相对姿态数据对于该型机安全着陆有着至关重要的作用。基于无线网络电台的双向数据传输系统能够实时获取进近段飞机相对理想着陆点的水平、垂直相对位置数据。通过上行链路上传着陆点的姿态数据，下行链路实时下传动动差分后的差分数据,最后在中心控制站进行二次数据处理。该技术获得的进近段二维相对姿态精度达到厘米级，满足飞行训练的需求。同时结合飞机显控数据以及视景图，以多角化动态关联的方式将实时获取的姿态数据等呈现给指挥员，更好地辅助指挥员进行着陆指挥工作。     

Fisher Information of Free-Electron Landau States

An electron in a constant magnetic field has energy levels, known as the Landau levels. One can obtain the corresponding radial wavefunction of free-electron Landau states in cylindrical polar coordinates. However, this system has not been explored so far in terms of an information-theoretical viewpoint. Here, we focus on Fisher information associated with these Landau states specified by the two quantum numbers. Fisher information provides a useful measure of the electronic structure in quantum systems, such as hydrogen-like atoms and under some potentials. By numerically evaluating the generalized Laguerre polynomials in the radial densities, we report that Fisher information increases linearly with the principal quantum number that specifies energy levels, but decreases monotonically with the azimuthal quantum number m. We also present relative Fisher information of the Landau states against the reference density with m=0, which is proportional to the principal quantum number. We compare it with the case when the lowest Landau level state is set as the reference.     

Tutorial review on validation of liquid chromatography–mass spectrometry methods: Part I

This is the part I of a tutorial review intending to give an overview of the state of the art of method validation in liquid chromatography mass spectrometry (LC–MS) and discuss specific issues that arise with MS (and MS/MS) detection in LC (as opposed to the “conventional” detectors). The Part I briefly introduces the principles of operation of LC–MS (emphasizing the aspects important from the validation point of view, in particular the ionization process and ionization suppression/enhancement); reviews the main validation guideline documents and discusses in detail the following performance parameters: selectivity/specificity/identity, ruggedness/robustness, limit of detection, limit of quantification, decision limit and detection capability. With every method performance characteristic its essence and terminology are addressed, the current status of treating it is reviewed and recommendations are given, how to determine it, specifically in the case of LC–MS methods.     

Is there any sense to investigate volumetric and acoustic properties of more binary mixtures containing Ionic Liquids?

The excess speed of sound, excess molar volume and excess molar isentropic compressibility of 52 binary mixtures containing Ionic Liquids at T = 298.15 K were calculated using selected literature speed of sound and density data. The second components were alcohols: methanol, or ethanol, or 1-propanol, or 2-propanol, or 1-butanol or other solvents: acetone, acetonitrile, tetrahydrofuran, dichloromethane and dimethylsulfoxide. The Balankina’s relative excesses, X_bal, i.e. the ratios between excess and ideal quantities X^E/X^id were also determined to reduce the structural impact of pure components to absolute excesses. Analysis of quantities determined shows some patterns for concentration dependences of large groups of mixtures; thus, the scheme for influence of anion or cation of Ionic Liquids and solvent on Balankina’s relative excesses was proposed. It seems that presented analysis provide the knowledge about absolute and relative excess quantities for other mixtures without doing the experimental work. It is also visible that analysis of excess molar quantities and X_bal parameters can support the interpretation of interactions which occur between Ionic Liquids and solvent.     

用平行双样测定结果相对偏差限值评估方法验证实验重复性限合理性的研究

分析方法标准验证实验得到的分析方法基本性能参数重复性限和再现性限是日常检测工作质控规范重要依据。以环境监测领域土壤、沉积物及固废样品中无机元素分析为例,考察了已颁布执行的标准文本和在生态环境部官网公开征求意见的分析方法标准中重复性限。将重复性限转化为相对偏差后,与日常检测工作中质控限值进行了比较。根据目前现行有效的平行双样测定结果相对偏差限值,方法验证数据有多大比例符合质控要求？根据方法验证结果,平行双样测定结果相对偏差限值有无改进可能？从上述两个角度进行了研究。研究结果表明：土壤、沉积物、固体废弃物中无机元素的测定,不同文献来源相同分析方法标准和不同分析方法标准,其重复性限转化得到的平行测定相对偏差合格率存在明显区别;用平行测定相对偏差限值可以快速判断标准文本中的重复性限是否合理,审核方法验证数据质量是否满足要求。基于已有标准文本方法验证数据,探讨了修改平行测定结果相对偏差限值可行性。     

超高效凝胶色谱法测定聚乙二醇衍生物的分子量及其分布

采用超高效聚合物色谱(APC)技术,以单甲氧基聚乙二醇丙醛(m PEG_p ALD)为代表,测定了聚乙二醇衍生物的相对分子质量及其分布和杂质含量,优选了色谱柱和流动相,考察了样品质量浓度变化以及溶解时间等对测定结果的影响。优化后3根超高效凝胶色谱柱串联,在柱温40℃,流动相95%甲醇,流速0.5m L/min,示差折光检测条件下,对m PEG_p ALD的分子量及其分布进行测定,同时得到杂质的相对含量。结果测得m PEG_p ALD主成分的重均分子量(Mw)为19 444,分布指数(D)为1.01;杂质1的Mw为38 703,D为1.01,含量为1.31%;杂质2的Mw为61 036,D为1.00,含量为0.70%。与常规凝胶渗透色谱(GPC)相比,该方法分辨率高,分析速度快,能快速测定m PEG_p ALD的相对分子量及其分布,并能得到其纯度和杂质含量,为其工艺研发、质量控制提供了科学的依据,同时也可用于其它PEG衍生物的相对分子量及其分布和纯度的测定。     

不同等级煤与油共炼的转化率差异及残渣分析

选取安徽褐煤、辽宁褐煤和贵州烟煤三种煤为原料,以油溶性环烷酸钼为催化剂,分别与马瑞常渣(MRAR)、克炼常渣(KAR)以及催化裂化油浆(FCCS)在高压釜内模拟悬浮床加氢共炼反应。结果表明,不同的油体系下,两种褐煤都能达到83%以上的转化率,而对于贵州烟煤,转化率最高的FCCS体系与最低的KAR体系分别为67.75%和50.31%,相差很大。采用FT-IR和SEM分析反应后固体残渣,计算了固体残渣中脂肪族和芳香族中各个基团的相对含量,并对比了不同体系反应后固体残渣的微观形貌。结果表明,KAR体系的固体残渣脂肪链较长,支链化程度高,取代度较低。转化率较高的褐煤反应后固体残渣结构松散,分散度高;转化率较低的烟煤固体残渣随着转化率降低,残渣颗粒逐渐变大,表面更加光滑,板结程度加深。