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排序方式: 共有92条查询结果,搜索用时 15 毫秒
1.
Wang Li Gong Hua-Jun Liu Chun-Sheng 《International Journal of Control, Automation and Systems》2019,17(3):617-629
International Journal of Control, Automation and Systems - In this paper, a composite fault-tolerant control problem is studied for a class of uncertain nonlinear system with asymmetric input... 相似文献
2.
介绍视觉技术在YP19装封箱机的装箱过程中的应用,简述视觉技术系统的基本组成、工作原理及软件设计。 相似文献
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4.
Xiao-Yan Chang Xin-Hai Li Long Zhang Hua-Jun Guo Wen-Jie Peng 《Materials Research Bulletin》2005,40(9):1513-1520
Pure and carbon-containing olivine LiMn0.7Fe0.3O4 were synthesized at 600 °C by the method of solid-state reaction. Structure, surface morphology and charge/discharge performance of LiMn0.7Fe0.3O4 were characterized by X-ray diffraction, scanning electron microscopy, and electrochemical measurement, respectively. The prepared materials with and without carbon both show the single olivine structure. The morphologies of primary particles are greatly affected by the addition of carbon. Large particles (500-1000 nm) and densely sintered blocks were observed in pure LiMn0.7Fe0.3PO4, which made the insertion and extraction of lithium ions difficult. Battery made from this sample can not charge and discharge effectively. The carbon-containing LiMn0.7Fe0.3PO4 has a small particle size (100-200 nm) and a regular appearance. This material demonstrates high reversible capacity of about 120 mAh g−1, perfect cycling performance, and excellent rate capability. It is obvious that the addition of carbon plays an important role in restricting the particle size of the material, which helps to prepare LiMn0.7Fe0.3PO4 with excellent electrochemical performance. The electrochemical reaction resistance is much lower in the partly discharged state than in the fully charged or fully discharged state by the measurement of ac impedance for carbon-containing LiMn0.7Fe0.3PO4. It is indicated that the mixed-valence of Fe3+/Fe2+ or Mn3+/Mn2+ is beneficial to the transfer of electron which happens between the interface. 相似文献
5.
The pursuit for detecting the existence of Majorana fermions is a challenging task in condensed matter physics at present. In this work, we theoretically propose a novel nonlinear optical method for probing Majorana fermions in the hybrid semiconductor/superconductor heterostructure. Our proposal is based on a hybrid system constituted by a quantum dot embedded in a nanomechanical resonator. With this method, the nonlinear optical Kerr effect presents a distinct signature for the existence of Majorana fermions. Further, the vibration of the nanomechanical resonator will enhance the nonlinear optical effect, which makes the Majorana fermions more sensitive to be detected. This proposed method may provide a potential supplement for the detection of Majorana fermions. 相似文献
6.
为了确保机组的安全经济运行,汽包水位控制受到高度重视,但或多或少都存在一定的不足.本文主要阐述了SIEMENS V94.3A型燃气轮机机组高压汽包水位存在的问题,分析其原因并采取相应的措施,使其满足安全运行要求. 相似文献
7.
This paper describes a template-assisted method that combines the advantages of photolithography and electrochemical synthesis to construct a wafer-scale Au flower-like structure microarray. The detailed information about the effect of concentration of electrolyte, pattern of template substrate, applied potential, and surfactant on the formation of Au flower-like microarray is investigated. The possibility of using such a microarray as electrodes for their electrochemical properties is also tested by CV experiments. 相似文献
8.
Yue-Ming?Li Wen?ChenEmail author Qing?Xu Jing?Zhou Hua-Jun?Sun Mei-Song?Liao 《Journal of Electroceramics》2005,14(1):53-58
The ternary lead-free piezoelectric ceramics system of (1 – x) [0.88Na0.5Bi0.5TiO3-0.12K0.5Bi0.5TiO3] – xNaNbO3(x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by conventional solid state reaction method. The crystal structure, dielectric, piezoelectric properties and P-E hysteresis loops were investigated. The crystalline structure of all compositions is mono-perovskite phase ascertained by XRD, and the lattice constant was calculated from the XRD data. Temperature dependence of dielectric constant r and dissipation factor tan measurement revealed that all compositions experienced two phase transitions: from ferroelectric to anti-ferroelectric and from anti-ferroelectric to paraelectric, and these two phase transitions have relaxor characteristics. Both transition temperatures Td and Tm are lowered due to introduction of NaNbO3. P-E hysteresis loops show that 0.88Na0.5Bi0.5TiO3-0.12K0.5Bi0.5TiO3 ceramics has the maximum Pr and Ec corresponding to the maximum values of electromechanical coupling factor Kp and piezoelectric constant d33. The piezoelectric constant d33 and electromechanical coupling factor Kp decrease a little, while the dielectric constant 33T/0 improves much more when the concentration of NaNbO3 is 8 mol%. 相似文献
9.
针对监督分类中的特征选择问题, 提出一种基于量子进化算法的包装式特征选择方法. 首先分析了现有子集评价方法存在过度偏好分类精度的缺点, 进而提出基于固定阈值和统计检验的两种子集评价方法. 然后改进了量子进化算法的进化策略, 即将整个进化过程分为两个阶段, 分别选用个体极值和全局极值作为种群的进化目标. 在此基础上, 按照包装式特征选择遵循的一般框架设计了特征选择算法. 最后, 通过15个UCI数据集分别验证了子集评价方法和进化策略的有效性, 以及新方法相较于其它6种特征选择方法的优越性. 结果表明, 新方法在80%以上的数据集上取得相似甚至更好的分类精度, 在86.67%的数据集上选择了特征个数更小的子集. 相似文献
10.
知识图谱补全能让知识图谱变得更加完整.现有的知识图谱补全工作大多会假设知识图谱中的实体或关系有充足的三元组实例.然而,在通用领域,存在大量长尾三元组;在垂直领域,较难获得大量高质量的标注数据.本文针对这一问题,提出了一种基于知识协同微调的低资源知识图谱补全方法.本文通过已有的结构化知识来构造初始的知识图谱补全提示,并提出一种协同微调算法来学习最优的模板、标签和模型的参数.本文的方法同时利用了知识图谱中的显式结构化知识和语言模型中的隐式事实知识,且可以同时应用于链接预测和关系抽取两种任务.实验表明,本文的方法在3个知识图谱推理数据集和5个关系抽取数据集上都取得了目前最优的性能. 相似文献