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81.
本文从东周至秦汉中期政治与社会转型的视角出发,在细致回顾与评析学界对"天下"观念进行研究的基础上,从美术史视角通过分析这一时期衍生的带有皇权建构与空间表现特征的美术材料,从而提出对该课题进行重新研讨的可行性。 相似文献
82.
李艳辉 《吉林化工学院学报》2014,(6):24-25
在二语习得的过程中,母语会起到一定的负面影响或干扰作用。但这只是表面现象,实际上母语能够帮助学习者完成语言交际的任务。母语既是外语学习不可或缺的背景和基础,又是可以开发利用的资源。重点探讨了母语文化对外语学习的促进作用。 相似文献
83.
刘勇 《徐州建筑职业技术学院学报》2014,(3):75-79
为考察台湾地区的旅游资源形象和旅游服务接待水平,通过对江苏省赴台游客进行问卷调查,获得了大量大陆游客赴台湾旅游旅游体验的第一手资料,并对其进行模糊综合评价分析,得出台湾旅游发展中自然景观特色较弱,娱乐项目安排不足等问题.并根据大陆游客对各因子满意度和关注度,将因子分类,提出了改善自然景观、娱乐项目的安排、旅游交通条件,增加大陆赴台旅游的自由行城市数量等策略. 相似文献
84.
Yuan Xue Lihong Wang Hualin Lin Sheng Han Shiyou Zheng 《Journal of the American Oil Chemists' Society》2021,98(9):943-954
The utilization and popularization of biodiesel are always limited by its poor cold flow properties. Both bio-based alcohol and diesel from direct coal liquefaction (DDCL) has potential to enhance the cold flow properties of biodiesel. In this study, ternary blends of waste cooking oil biodiesel (BWCO) with DDCL and bio-based ethanol (ET) or 1-butanol (BT) were conducted to improve the cold flow properties of biodiesel. The pour point (PP), cold filter plugging point (CFPP), and cloud point (CP) of BWCO-ET, BWCO-BT, and BWCO-DDCL binary blends, and BWCO-ET-DDCL and BWCO-BT-DDCL ternary blends were comparatively assessed. Ternary phase diagrams were also applied to analyze the blending effect of the three components on the cold flow properties of biodiesel. Results showed that both DDCL, ET, and BT can remarkably enhance the cold flow properties of BWCO. When the ternary blends contain 20 vol.% BWCO and less than 40 vol.% ET or BT, DDCL together with ET or BT exerted positive effects on enhancing the low-temperature flow properties of BWCO, especially on the CP and CFPP. For ternary blends in 20:10:70 blending ratio, BWCO-BT-DDCL exhibited the lowest PP, CFPP, and CP of −23, −19, and −17°C, respectively. The crystallization behavior and crystal morphology of blended fuels are also observed via a polarizing optical microscope, and find that DDCL together with BT in biodiesel can effectively retard the aggregation of large crystals and inhibit crystals growth. 相似文献
85.
A novel grating matching method for 3D reconstruction 总被引:2,自引:0,他引:2
Automatic 3D surface reconstruction has been an important research topic in digital photogrammetry for many years. Shaping from stereoscopic information is one of the widely studied topics in computer vision. Its central part is to solve the stereo matching problem automatically. Most algorithms used to solve the matching problem can be categorized as either area-base techniques or feature-based techniques. Feature-based techniques have gained more and more popularity for and it is the method that supports activities in object recognition and image understanding. But none of the former research can ensure the 100% matching exactness, thus, cannot complete high precision 3D surface measurement. In order to improve the precision of 3D measurement, we design a novel grating matching method, which can ensure 100% matching accuracy. It does not need any other assistant symbol or flag, only select one of the gratings which have to be projected to the objects. On the beginning of the measurement, the background of the object is captured by a CCD camera. Later gratings include single grating and group gratings will be projected to the object in sequence. All the images include gratings will make a subtraction with the background. The difference of the two images will be treated as 3D cues to acquire the 3D shape. Because no recognizing work is needed, the location of the single grating and each one in the group can be positioned exactly. From a lot of experiments, the proposed grating matching method is proved and it is a technique with high precision, low costs, easy operation, and an automatically matching method. Furthermore, it can be widely used in most of 3D vision recovery systems. 相似文献
86.
The effect of substrate condition and annealing treatment on the surface morphology of sputter-deposited NiTi-based thin films was studied by means of atomic force microscope. It is found that the surface of the film deposited at 450 °C on a (100) Si wafer is composed of large island groups, consisting of islands of 150–300 nm in diameter. Annealing treatment at 400 °C results in a more homogeneous distribution of the island size. However, for the film deposited at 450 °C on a (111) Si wafer, its surface consists of more homogeneous islands, being about 200–250 nm in diameter. For the film deposited at 450 °C on a SiO2 buffer layer on top of the Si-substrate, the surface islands have ideal spherical shape. After annealed at 650 °C, the islands have grown to about 300 nm in width and 550 nm in length. The surface roughness of the deposited film is related not only to the island sizes but also to the island distributions. 相似文献
87.
近年来 ,我国MBA的社会评价不高 ,其根本原因是MBA毕业生不能满足市场要求。本文通过分析管理史的功能 ,得出学习管理史对MBA的边际效用大 ,MBA培养方案中有必要增设管理史类的课程。 相似文献
88.
The stability of austenite in a number of Fe–Mn–Si-based shape memory alloys has been investigated. It was found that a grain boundary precipitate of BCC structure is formed over a wide range of alloy compositions and heat treatment temperatures. This grain boundary phase has been identified as the chi (χ) phase. Although up to 3 vol.% of the grain boundary precipitate was generated by isothermal aging in the range 500–800 °C, it was found not to markedly affect the mechanical properties or the shape memory effect. Nano-indentation indicated that the hardness and strength of the parent and precipitate phase are very similar, as are their compositions. 相似文献
89.
采用正交设计现场浇注,试验研究了铸钢件冒口离开热节动态补缩特性。结果表明,冒口位置对补缩效果影响显著,铸钢件冒口在离开铸件的几何热节处,实施动态顺序凝固补缩,提高了冒口补缩效率和工艺出品率。在试验条件下,冒口离开何热节的距离为一倍热节圆直径时,补缩效果良好。 相似文献
90.
简要叙述不锈钢板冷轧机(20辊森吉米尔轧机、四柱式2O辊轧机、12辊CR轧机等)的结构特点、发展概况及各自采用的先进控制系统。 相似文献