The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The Partial Least Squares (PLS) algorithm has been widely applied in face recognition in recent years. However, all the improved algorithms of PLS did not utilize non-negativity and sparsity synchronously to improve the recognition accuracy and robustness. In order to solve these problems, this paper proposes a novel algorithm named Two-Dimension Non-negative Sparse Partial Least Squares (2DNSPLS),...
For benefiting from incorporating the class information, partial least squares (PLS) and its two dimension version (2DPLS) have been widely employed in face recognition when extracting principal components. However, currently popular statistic methods, such as principal component analysis (PCA) and linear discriminant analysis (LDA), only learn holistic, not parts-based, representations which ignore...
Recent developments in polymeric dielectric nanocomposites have shown that these novel materials can improve design of high voltage components and systems. MMT(Montmorillonite)has an excellent corona performance and PI/MMT nanocomposite films can be prepared by in-situ polymerization process in this paper. Dielectric properties and trap level characteristic were measured by broadband dielectric spectrometer,...
In order to investigate the corona ageing mechanism of polyimide and polyimide/Al 2 O 3 nanocomposites, effects of corona ageing on the structure changes of the two polymers were studied. The physical and chemical changes were studied by Atomic Force Microscope (AFM), Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectroscope (FTIR) respectively. Modified isothermal...
In order to investigate the trap level distribution in polymer films, a new method is proposed based on modified thermally stimulated current (TSC) theory and numerical calculation of the TSC measurement. In this method, a new function is defined to weight the contribution of every trap level to the external current. The demarcation energy is used to study the trap emptying process. The modified TSC...
Modified isothermal discharge current method (MIDC) was introduced to investigate the trap level distribution in Kapton 100HN and 100CR (nanodielectrics) PI films before and after corona ageing. The physical and chemical changes were studied by AFM and FT-IR respectively. Experiments showed that the quantity of traps was increased evidently after corona ageing and lots of deeper traps were produced...
Nanohybrid polymers have many excellent properties, such as high dielectric constant, high dielectric strength and low loss and so on, which apply in the electricity and electron fields widely. In this paper, the nanohybrid Al2O3/PI films were prepared by Sol-Gel process, then, Au and Al were sputtered on the films surface respectively as electrode. The dielectric properties (dielectric constant,...
In order to investigate the roles of inorganic nanoparticles on improving breakdown behavior of Al2O3/PI film, the DC breakdown characteristics were studied in this paper. The morphology and element distribution of zones near the breakdown holes were observed by SEM and electron spectroscope for both the original PI film and Al2O3/PI nanocomposite film. The experimental results showed that the electrical...
The internal electric field and potential in thin polymer film caused by injected charges were numerically analyzed and some paradoxical TSDC experimental results and the effect of internal electric field on the trap parameters obtained from TSDC measurement were discussed. It's found that, under short-circuit of the external electrodes, one zero electrical field plane and one potential peak appeared...
Thermally stimulated current (TSC) is developed and a new method for direct determination of trap level distribution in polymer film is proposed. In this method, a new function is defined to weight the contribution of a trap level to the current at any temperature. The demarcation energy is used to study the trap empty process. Analysis shows that only electrons with trap levels very close to the...
Inorganic nanohybrid polyimide (PI) film has great potential for applications in the areas of electrics and electronics because of its excellent electrical performance, such as the resistance to aging and corona and so on. The breakdown strength of insulating materials is generally measured by DC, AC or impulse voltage. However, the influence of laser irradiation to Al2O3/ PI film has not been reported...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.