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921.
The global responses characteristics of a rotor/stator rubbing system with dry friction effects 总被引:2,自引:0,他引:2
Rotor/stator rubbing systems may undertake a number of quite different responses. Recent experiments on rotor/stator rubbing have revealed that two or three different responses may coexist. In this paper the global response characteristics of a general rotor/stator rubbing system, which takes into account the dominant factors in the process of rotor/stator rubbing, especially, the dry friction effect that is mostly neglected in the previous works and is the main factor for the self-excited dry friction backward whirl, are studied. The different solutions of the piecewise nonlinear system are derived and their stability are analyzed to get the existence boundaries of the different responses. An overall picture of the global response characteristics of this model is then obtained by drawing the existence boundaries in a same parameter space. The present results provide good understanding on the coexistence of different rubbing responses observed in tests. Moreover, deeper insight into the types of coexistence of different rubbing responses and their relationship with the system parameters is gained. 相似文献
922.
In this article, we consider a stochastic hydrodynamical equation in Heisenberg paramagnet driven by additive noise. We prove
the existence and uniqueness of smooth solutions to this equation with difference method. 相似文献
923.
924.
For smooth or non-smooth unconstrained global optimization problems, an one parameter filled function is derived to identify their global optimizers or approximately global optimizers. The theoretical properties of the proposed function are investigated. Based on the filled function, an algorithm is designed for solving unconstrained global optimization problems. The algorithm consists of two phases: local minimization and filling. The former is intended to minimize the objective function and obtain a local optimizer, the latter aims to find a better initial point for the first phase. Numerical experimentation is also provided. The preliminary computational results confirm that the proposed filled function approach is promising. 相似文献
925.
Ming-Cheng Yang Xue Tang Si-Wei Liu Hui-Qing Deng Jin-Ju Lei Ying-Juan Gao Bo Han Hai-Lei Cui 《Tetrahedron letters》2018,59(2):138-142
A K3PO4 promoted dipolar [3+3] cyclization of dihydroisoquinoline imines and arylacyl bromides has been developed. This process realized the direct synthesis of pyrazino[2,1-a]isoquinoline derivatives in 44–69% yields. A head to tail dimerization was proposed as key step for this procedure. 相似文献
926.
The DNA primary sequence is translated into “structure graph” based on classification of its four bases. Then the invariants, such as topological indices, are extracted from those graphic representations of DNA primary sequences, and used to calculate the similarities among the eleven species. From these similarities/dissimilarities the homologies can be revealed that they are in agreement with evolutionary relation satisfactorily. 相似文献
927.
在pH 2.2 BR缓冲介质中, 磷钨杂多酸(PTA)与格拉司琼(GSN)相互作用形成离子缔合物, 不仅引起吸收光谱的变化, 还导致共振散射光谱(RLS)的显著增强并产生新的RLS光谱, 最大RLS峰位于333 nm附近, 其RLS增强程度与格拉司琼浓度成线性关系, 检出限和线性范围分别为12 ng/mL和0.04~3.0 μg/mL。文中研究了反应产物的吸收和RLS光谱特征, 优化反应条件的影响, 据此发展了以磷钨杂多酸为光谱探针的灵敏、简便、快速测定格拉司琼的新方法。将方法用于血清中格拉司琼含量的快速定, 结果满意。讨论了离子缔合反应和RLS增强机理。 相似文献
928.
929.
CCD数码照相系统分辨率测试技术研究 总被引:1,自引:0,他引:1
介绍了CCD数码照相系统电视分辨率和空间分辨率的实验测试方法。以实验测试为基础定量地给出了数码照相系统可达到的分辨能力 (6 0 0TVL和 71条线 /mm)。在现有条件下 ,作者对传统冲洗金相显微照片同相同试样金相组织的电子金相照片进行了比较 ,并得到了满意的结果。 相似文献
930.
Red Electroluminescence and Photoluminescence from Novel Binuclear Europium Complex with Squaric Acid Ligand 总被引:1,自引:0,他引:1
Wei Guo ZHU* Xiao Qiang WEI Mei Xiang ZHU Zhi Yun LU Bo LIANG Ming Gui XIE De Qiang ZHANG Yong QIU College of Chemistry Xiangtan University Xiangtan Department of Chemistry Sichuan University Chendu Department of 《中国化学快报》2001,(10)
Organic electroluminescent devices (OELDs) have attracted much attention for several years because of their potential application in large area, multi-colored flat panel displays1-5. The green organic EL display using Alq3 as emitter was commercialized in 19976. However, red-emitting OELD with excellent properties has not been well developed. In order to realize practical full-color OELDs, it is considered very important to develop red and blue emitting materials with excellent propert… 相似文献