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A large electrolytic capacitor is always used to provide stable DC-link voltage in single-phase to three-phase power converter. However, the large electrolytic capacitor occupies a large volume and has a short lifetime as to the home appliances. And additional PFC circuit is needed to correct the grid current. In order to settle these issues, an electrolytic capacitor-less converter system is studied...
Synthetic aperture Radar tomography has been widely used in 3D reconstruction in urban area. It can distinguish multi persistent scatterers in the same range-azimuth resolution cell. But how to detect and estimate the number and parameters of persistent scatterers is still an important and difficult problem need to be resolved. In this paper, a new method based on RELAX and generalized likelihood...
Gas turbine engine anomaly detection is a critical means to ensure the safety and economic efficiency of a flight. As gas path faults make up a sizeable proportion of all the engine faults, an engine gas path anomaly detection method was proposed in the present article. Inspired by recent progress in deep learning, we explored a method that combined deep learning with traditional anomaly detection...
Science culture makes crucial contribution to the city as an innovation center. Firstly, science culture could result in friendly economy context for innovation, related to the finance and the marketing of the city, involving consumers, jobs, innovation clusters and infrastructures. Secondly, an active science culture provide positive social environment to cultivate innovative talents, concerned with...
Human resources in science and technology (HRST) is an important component of innovative talents. The amount, structure and efficiency of HRST in a country, determine the strength of national innovation and potential development in science and technology field. In China, the amount of HRST reached to 81.14 million with ranking the first in the world until the end of 2014. Obviously, the main body...
WeChat is a new generation of mobile instant messaging product, which has over 800 million active accounts and support voice, video, pictures and text messages. China's Ministry of Science and Technology has applied social media to science and technology management. Rui Dong Ruan is one of the official accounts in the WeChat matrix of China's Ministry of Science and Technology. This research proposes...
A novel 4H-SiC metal semiconductor field effect transistor with localized high-doped P-buffer layer is proposed in this paper. Compared with conventional structure, because of the higher doped concentration in the P-buffer layer between the gate and the drain, greater depletion layer generates and extends to the channel, which reduces the concentration of channel carrier and modulates electric field...
Correct incipient fault diagnosis is crucial to the health management of the analog circuits, though remaining challenging. This paper presents a novel fault diagnosis method to diagnose ordinary soft fault and incipient soft fault for linear analog circuit. Due to the presence of analog circuit noise stress and the tolerance of the components, the linear circuit responses are considered as a stochastic...
An improved latent correlation anomaly detection (LCAD) method is proposed to detect anomalies from condition monitoring datasets of industrial equipment. Above all, original data were segmented to various work cycles. Then, latent correlation vector (LCV) was used to denote the latent correlation among different parameters. Based on a latent correlation probabilistic model (LCPM), an anomaly detection...
Combing FSS technology with absorbing conception, an FSS radome with absorptive and transmissive characteristics is presented in the paper. It can transmit electromagnetic wave at around 20.5 GHZ. And below the transmission band, it can absorb energy at the frequency range of 5∼15GHz with Sit and S21 both less than −10dB, and with the absorption rate more than 80% (even up to 95% at some frequency...
Minimizing the thermal gradients is extremely important in a planar solid oxide fuel cell (SOFC) for improving the cell life. The estimation of the temperature distribution in the cell is necessary since it is difficult and costly to measure the temperature inside a high temperature, well-sealed cell directly. In this paper, a nonlinear Luenberger observer has been designed for estimating the temperature...
A large electrolytic capacitor is always used to make dc-link voltage stable in a single-phase to three-phase power converter. However, the large electrolytic capacitor occupies a large volume and has a short lifetime as to the home appliances. And additional PFC circuit is needed to correct the grid current. In order to settle these issues, a converter without electrolytic capacitor is studied in...
This paper proposed an inner current loop control method for a grid-connected inverter with a LCL filter, which used the inverter side current as feedback parameter. Due to the sensitivity of grid current to grid voltage distortion, the grid voltage feedforward schemes were utilized to solve this problem. Nevertheless, the sampling distortion of grid voltage will bring about the distortion of grid...
In this paper, Gini coefficient is introduced into the allocation of investments in electric power subsidiaries. First, three indicators including the return on total assets, future forecasted electricity consumption and the investment to electricity sales ratio are used to determine the initial allocation scheme of future grid investment in subsidiaries. The initial scheme ensures benefits (efficiency)...
The millimeter wave real-time imaging radar has the capabilities of high range resolution and Doppler resolution, which puts forward a new challenge for digital signal processor. Based on the analysis of technical characteristic of real-time imaging radar, a new kind of digital signal processor structure is presented. The processor adopts multi DSPs and multi FPGAs structure. And the design methods...
Personal cloud storage is rapidly gaining popularity. A number of Internet service providers, such as Google and Baidu, entered this emerging market and developed a variety of cloud storage services. These ubiquitous services allow people to access personal files all over the world at anytime. With the prevalence of mobile Internet and rich media on web, more and more people use cloud storage for...
This paper studies a sensorless drive system of interior permanent magnet synchronous motor (IPMSM) fed by single phase diode rectifier with small dc-link capacitor. Because the large electrolytic capacitors have the disadvantages of both large volume and limited life span, the system uses small dc-link capacitor instead of traditional large electrolytic capacitor. In the system, the inverter controls...
This paper studies a speed sensorless permanent magnet synchronous motor (PMSM) drive system based on the adaptive observer method, analyzes the problem of instability in the low-speed electric mode according to the observer linearization method. To solve this problem, the observer augmented with a signal injection technique is researched. The simulation results show that the method is effective to...
Objective: To analyze the component law of Chinese medicines for osteonecrosis of the femeral head, and develop new prescriptions for osteonecrosis of the femeral head through unsupervised data mining methods. Methods: Chinese medicine recipes for osteonecrosis of the femeral head were collected and recorded in the database, and then the correlation coefficient between herbs, core combinations of...
Friendship prediction in social networks is useful for various applications, such as friend/place recommendation and privacy management. In this paper, we propose a friendship prediction approach by fusing the topology and geographical features in location based social networks (LBSNs). We investigate the features of users' relationship both online and offline and quantify the contributions of selected...
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