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191.
对简笔画的特点进行分析发现,它在教学中起着重要的作用,简笔画易懂、易学,是教师必备的基本职业技能。师范类高校英语教育专业增设简笔画课程是非常必要的。  相似文献   
192.
动态硫化技术及其发展   总被引:3,自引:0,他引:3  
孙文源  刘彦驹 《弹性体》1991,1(4):56-61
结合动态硫化技术的发展史,重点评述了国外80年代该技术的发展及其特点,揭示了TPV性能及特征与制备条件的关系;简介我国开发研究TPV的概况,并提出了看法。  相似文献   
193.
Ren Tao  Liu Qingyou 《Advanced Robotics》2014,28(17):1165-1175
The modern society is fuelled by very comprehensive grids of gas and liquid pipelines. In recent years, various in-pipe robots have been developed for inspection and maintenance tasks inside such pipes. In this paper, a novel in-pipe robot is proposed and developed for gas/oil well interventions at thousands of meters downhole. Due to the nature of such intervention, in-pipe robot design must be capable of carrying a very large payload, as large as 2500?N inside a pipe with diameter as small as 54?mm. The proposed design concept is based on a compound planetary gearing system. One of the major novelties of this design is the use of pipe wall as a ring gear for one stage of the compound planetary gear system; the other novelty is the generation of helical angle when the planetary gears are expanded to press on the pipe wall. The proposed concept is compact, efficient, and has never been reported before. In this paper, the helical angle, the velocity, and load capability of the proposed system will be analyzed. The load transportation capability of the proposed robot is also measured based on an experiment. Initial data have shown great potential in carrying large payloads.  相似文献   
194.
Collaboration representation-based classification (CRC) was proposed as an alternative approach to the sparse representation method with similar efficiency. The CRC is essentially a competition scheme for the training samples to compete with each other in representing the test sample, and the training class with the minimum representation residual from the test sample wins the competition in the classification. However, the representation error is usually calculated based on the Euclidean distance between a test sample and the weighted sum of all the same-class samples. This paper exploits alternative methods of calculating the representation error in the CRC methods to reduce the representation residual in a more optimal way, so that the sample classes compete with each other in a closer range to represent the test sample. A large number of face recognition experiments on three face image databases show that the CRC methods with optimized presentation residual achieve better performance than the original CRC, and the maximum improvement in classification accuracy is up to 12 %.  相似文献   
195.
In this paper, a new Chinese character recognition (CCR) approach is proposed based on the fuzzy clustering analysis theory. Chinese characters (CCs) have various similar radicals and stroke components, which make it difficult to recognize features in the CCR process. At the same time, the recognition accuracy and the efficiency are lower when the objects to be recognized are complex. In order to solve these problems, a fuzzy clustering analysis method is introduced to enhance the computing efficiency. At first, the CCs including learning samples and testing samples are transformed into binarization templates in the form of matrixes. Then, the minimum distance algorithm is applied to calculate ‘distances’ between the testing sample templates and the learning sample templates. At last, the character recognition can be achieved by searching the minimum distance from the results. The experiment results of the CCR process can prove the effectiveness and accuracy of the new method.  相似文献   
196.
关注非异氰酸酯聚氨酯(NIPU)涂料的应用和发展   总被引:5,自引:0,他引:5  
刘登良 《中国涂料》2006,21(11):21-23
介绍了NIPU涂料发展的现状,阐述其特点,主要原材料聚碳酸酯和多元胺的反应动力学,杂化HNIPU的概念及其应用前景。  相似文献   
197.
煤中吡啶型氮热解机理的量子化学研究   总被引:1,自引:1,他引:1  
用密度泛函 ( DFT)方法 ,在 UB3LYP/6- 31 G( d)水平上研究了煤中吡啶型氮的热解机理 ,对热解过程中由于官能团周围环境的不同而形成的三类吡啶自由基进行了量子化学计算 ,通过对键的 Mulliken布居数等计算结果的分析 ,分别得到了这三类自由基的热解途径 .并优化得到了反应物、中间体和产物的几何构型 .计算结果表明 ,吡啶型氮主要是以 HCN的形式释放出来的 .NH3 是 HCN二次反应的产物 .  相似文献   
198.
对6种苯并噻唑偶氮吡唑化合物的分析特性进行了探讨,着重研究了4—(6′—甲基苯并噻唑-2′-偶氮)-3,5-二氨基吡唑(MBTAP)与钯离子显色反应的光度性质。在非离子表面活性剂 Brij35存在下与钯离子形成橙红色的配合物。适宜的 pH 值范围为9.0~10.5.配合物的最大吸收波长为510nm,表观摩尔吸光系数为3.01×10~4L·mol~(-1)·cm~(-1)。钯在0~14μg/25mL,范围内服从比尔定律.显色体系可稳定11h。在柠檬酸存在下可消除 Fe~(3+)、Co~(2+)、Cu~(2+)、Ni~(2+)等离子的干扰。  相似文献   
199.
The molten salt synthesis (MSS) method is utilized to synthesize the anisotropic platelet Sr3Ti2O7 (S3T2) single-crystal particles. The aim of this study is to identify the essence of platelet Sr3Ti2O7 crystal growth and guide the synthesis of anisotropic platelet SrTiO3 crystals as well as various technologically important materials. Based on the results of X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy, the formation mechanism of platelet Sr3Ti2O7 crystals conforms to a nucleation–structure rearrangement–dissolution–diffusion in situ epitaxial growth mechanism model. First, SrCO3 reacts with TiO2 to form submicrometer SrTiO3 nuclei. Then, most of the nuclei surrounded by salt ions aggregate and rearrange to form a large SrTiO3 matrix. The structural rearrangement and the subsequent in situ epitaxial growth processes control the morphology, composition, and size of the final Sr3Ti2O7 crystals. In the synthesis process, the conversion between SrTiO3 and Sr3Ti2O7 is as follows: and the crystallographic orientation relationship between Sr3Ti2O7 and SrTiO3 in the interface is (100)S3T2//{100}ST, (010)S3T2//{010}ST, and (001)S3T2//{001}ST.  相似文献   
200.
The fabrication of monolayers composed of nordihydroguaiaretic acid (NDGA), and hybrid films composed of NDGA-flavin adenine dinucleotide (FAD) adsorbed films was performed in neutral aqueous solutions to produce electrochemically active thin films exhibiting one and two redox couples, respectively. An electrochemical quartz crystal microbalance and cyclic voltammetry were used to study the in situ growth of the NDGA and hybrid NDGA/FAD film monolayers. The NDGA modified film electrocatalytically oxidized NADH, ascorbic acid, dopamine, and N2H4 in neutral aqueous solutions. Well-separated voltammetric peaks were observed for dopamine and uric acid mixtures, and also for ascorbic acid and uric acid mixtures using the NDGA/GC modified electrode. When transferred to various aqueous buffered solutions, the two redox couples of the NDGA/FAD hybrid film and their formal potentials were observed to be pH-dependent. The electrocatalytic oxidation and reduction of NADH and NAD+ by a NDGA/FAD hybrid film in neutral aqueous solutions was carried out, and the electrocatalytic oxidation of NADH was performed using a NDGA/FAD hybrid film.  相似文献   
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