基于数学形态学和BP神经网络的足趾形状识别方法

根据足趾二值图像形状特征,提出基于数学形态学消散度技术的足趾形状特征提取及BP神经网络聚类的足趾形状识别方法。该法依据数学形态学理论提取物体形心,仅受较少边界凹点影响,对噪声不敏感,比几何中心稳定。提取边界上距形心距离稳定并能区分不同形状的特征点及相互关系,生成特征向量。此向量在二维连续空间中,具有平移、旋转、尺度不变特征;在二维离散应用环境中,由平移、旋转、尺度变化造成误差小,稳定性强。用训练成功的BP神经网络,对不同质量足趾图像识别,均能达到较高识别率。大量实验表明,该法是满足识别精度要求、识别率高于其它方法的一种行之有效的足趾形状识别方法。     

Study on an iron–manganese Fischer–Tropsch synthesis catalyst prepared from ferrous sulfate

A systematic study was undertaken to investigate the effects of the initial oxidation degree of iron on the bulk phase composition and reduction/carburization behaviors of a Fe–Mn–K/SiO₂ catalyst prepared from ferrous sulfate. The catalyst samples were characterized by powder X-ray diffraction (XRD), Mössbauer spectroscopy, X-ray photoelectron spectroscopy (XPS) and H₂ (or CO) temperature-programmed reduction (TPR). The Fischer–Tropsch synthesis (FTS) performance of the catalysts was studied in a slurry-phase continuously stirred tank reactor (CSTR). The characterization results indicated that the fresh catalysts are mainly composed of α-Fe₂O₃ and Fe₃O₄, and the crystallite size of iron oxides is decreased with the increase of the initial oxidation degree of iron. The catalyst with high content of α-Fe₂O₃ in its as-prepared state has high content of iron carbides after being reduced in syngas. However, the catalyst with high content of Fe₃O₄ in its as-prepared state cannot be easily carburized in CO and syngas. FTS reaction study indicates that Fe-05 (Fe³⁺/Fe_total = 1.0) has the highest CO conversion, whereas Fe-03 (Fe³⁺/Fe_total = 0.55) has the lowest activity. The catalyst with high CO conversion has a high selectivity to gaseous hydrocarbons (C₁–C₄) and low selectivity to heavy hydrocarbons (C₅₊).     

Stress concentration degree affects spontaneous magnetic signals of ferromagnetic steel under dynamic tension load

Under the excitation of geomagnetic field, stress can induce spontaneous magnetic signals in ferromagnetic materials, which can be potentially applied to estimate the damage degree. In this research, the normal component of magnetic field, H_p(y), was measured during dynamic tension test on the surfaces of ferromagnetic specimens having different stress concentration factors, α constant amplitude sinusoidal tensile load cycles were applied on 18CrNi4A steel plate specimens whose α were respectively 1, 3 and 5. Then correlation of H_p(y) values’ changes with loading cycles reported. The results indicate that stress concentration factor, α extremely affects the magnetic signal, the absolute value of the gradient, |K|, increases with the increase of α. Meanwhile, |K| also goes up when loading cycle increases in the initial state. However, after a few cycles, those H_p(y) curves corresponding to different cycles become similar before cracking.     

空间2自由度5杆RCCCR机构速度波动分析

机械系统运转时 ,由于原动件上的力矩波动将引起机械速度的周期性波动 ,从而影响机械的工作精度 ,因此空间机构的速度波动分析是空间机构动力学中的一个重要的研究方向。以空间 2自由度 5杆RCCCR机构为例 ,建立运动微分方程 ,并求解其速度波动情况 ,进而为空间机构的速度波动调节提供了依据     

堆载预压法处理软土时计算固结度的几种方法

在用堆载预压法处理软基时，大多用土体同结度和承载力指标来评价地基处理效果。但受处理区域土体物理力学性质及地质结构、堆载速率和荷载的实际施工情况等影响，固结度并非定值。为了真实反映固结度，常采用一些监测手段来获取土体固结度。现通过用不同方法计算固结度来评价地基处理效果，结合设计要求，以判断堆载预压卸荷的条件。     

Graphs with maximum degree 6 are acyclically 11-colorable

An acyclic k-coloring of a graph G is a proper vertex coloring of G, which uses at most k colors, such that the graph induced by the union of every two color classes is a forest. In this note, we prove that every graph with maximum degree six is acyclically 11-colorable, thus improving the main result of Yadav et al. (2009) [11].     

中专数学试题库试后统计与分析程序设计

《试后统计与分析》具有题分录入，客观题自动阅卷，计算每人得分，输出成绩单，输出考分分布情况及判断是否符合近似正态分布，进行试题与试卷质量分析；建立成绩档案库等功能。     

Optimization of preparation conditions of carboxymethyl potato starch through orthogonal experimental design

To optimize the preparation conditions of carboxymethyl potato starch (CMPS), the effects of relevant factors on viscosity (η) of 2% CMPS aqueous solution and degree of substitution (DS) were investigated. These condition parameters included etherification temperature, alkalization and etherification time, water content in the mixed solvent, ratio of liquid volume to starch mass, molar ratio of sodium hydroxide to monochloroacetic acid, and molar ratio of monochloroacetic acid to anhydroglucose unit. After individual parameter influencing η and DS was researched one by one, an orthogonal experiment of L₁₈ (2 × 3⁷) was designed to identify the main factors affecting them. In light of range analysis, the comparative importance of factors impacting η and DS was obtained, separately. Results of variance analysis showed that the most effective factor to control DS was etherification temperature, whereas the influences of all factors on η were not significant. Meanwhile, η and DS of the optimized final product were found to be 12,000 mPa.s and 0.68, respectively. In addition, the structure of CMPS was characterized by Fourier transform infrared (FTIR) spectrophotometer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Dynamic Characteristics Analysis of Two‐DOF Oscillatory Actuator and Experimental Verification of Prototype

Recently, linear oscillatory actuators have been used in a wide range of applications. In particular, small linear oscillatory actuators are expected to be used in haptic devices by being extended to provide multi‐degree‐of‐freedom motion with arbitrary acceleration. In this paper, we propose a compact two‐DOF oscillatory actuator that can move in various directions on a plane. The static and dynamic characteristics of the actuator are determined by the 3D finite element method. The effectiveness of this method is shown through a comparison of the measured results with the experimental results from a prototype. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(1): 58–65, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22312     

烟煤粘结指数测定中搅拌方法的改进

根据GB/T 5447-1997烟煤粘结指数测定方法,结合粘结指数测定中的实际操作经验,分析了煤的混匀程度对粘结指数测定准确性的影响,同时针对现有的搅拌方法进行了改进,并取得了很好的效果。