Papers by Keyword: Reliability

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Authors: Ahmet Gayretli
Abstract: Electromechanical products such as electrical toothbrushes and robots carry multitechnological characteristics, and functional operation of these systems is depended on the successful operation of all system components. There are interactions between electronic and mechanical components, software and other systems in complex products. These interactions such as heat, vibration, gravity, corrosion and electromagnetism can lead to functional and financial losses and failures of these kinds of products. The physical arrangement and mutual relation of subsystems and parts are very important to design reliable and robust systems. However, designing these products is complicated and time-consuming due to limitations on available expertise, tools, and methods. This paper presents a new product development approach proposed for integrating mechanical design with electronic design to improve design and manufacture of electromechanical products in terms of customer requirements, reliability, structural integrity, weight, cost and time. This approach has been implemented in a Delphi based environment integrated with a CAD system. It assists in evaluating complex systems as far as parts relation and their possible effects on each other, costs, weight and physical constraints are concerned in the early design process. This helps the designers to avoid design iterations, and minimize the likelihood of failures and rapidly develop reliable complex products subject to given constraints.
457
Authors: E. Maset, Esteban Sanchis-Kilders, Pierre Brosselard, Xavier Jordá, Miquel Vellvehi, Phillippe Godignon
Abstract: Silicon Carbide 300V-5A Ni and W Schottky diodes with high temperature operation capability (up to 300°C) have been fabricated. This paper reports on the stability tests (ESA space mission to Mercury, BepiColombo requirements) performed on these diodes. A DC current stress of 5A has been applied to these diodes at 270°C for 800 hours. These reliability tests revealed both, degradation at the Schottky interface (forward voltage drift) and at the diode top surface due to Aluminum diffusion (bond pull strength degradation). The use of W as Schottky metal allows eliminating the forward voltage drift producing stable metal–semiconductor interface properties. Nevertheless, SEM observations of the top metallization still reveal metal degradation after stress. The bond pull strength of the wire bond is also significantly reduced.
925
Authors: Walter Daves, A. Krauss, V. Häublein, A.J. Bauer, L. Frey
Abstract: In this work we present 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs) with a stable protective coating for harsh environment applications. Both inversion channel (IC) and buried channel (BC) MOSFETs were realized on n-4H-SiC substrates with a p-epilayer. Stacked ONO gate dielectric and Ti/TiN/Pt/Ti interconnect were used. Ni and Ti ohmic contacts in combination with a-SiOx/a-SiNy and a-SiOx/a-SiC protective coatings were compared. The MOSFETs showed excellent transistor characteristics up to 600 °C and exceptional stability during long-term aging at 600 °C in air and during accelerated aging at 700 °C including temperature cycling and air/moisture environment.
1089
Authors: Kevin Matocha, Zachary Stum, Steve Arthur, Greg Dunne, Ljubisa Stevanovic
Abstract: SiC vertical MOSFETs were fabricated and characterized to achieve a blocking voltage of 950 Volts and a specific on-resistance of 8.4 mW-cm2. Extrapolations of time-dependent dielectric breakdown measurements versus applied electric field indicate that the gate oxide mean-time to failure is approximately 105 hours at 250°C.
1131
Authors: Ni Zhao, Xun Li
Abstract: The randomness of communication requirements and communication capabilities is the main reason that causes congestion as well as randomness of communication system service efficiency. Based on the analysis on effect of random factor on communication system requirements as well as random factors, such as interference, weather, accidents, on communication capabilities, the paper analyzed on randomness of communication requirements and communication capabilities and established functional function model of communication channel. Referring to reliability theory, the channel unblocked reliability index was defined. Through evaluation on congestion probability, the reliability of communication system running status was also analyzed. The research can provide reliability reference to design and planning of communication system.
2049
Authors: Keh Moh Lin, Yang Hsien Lee, Wen Yeong Huang, Po Chun Hsu, Chin Yang Huang, Zhu Fu Hsieh
Abstract: To find out the important factors which decisively affect the soldering quality of photovoltaic modules, solar cells were soldered under different conditions (different temperatures, PbSn vs. SnAgCu solder, manual vs. semi-automatic). Experimental results show that the soldering quality of PbSn under 350°C in the semi-automatic soldering process was quite stable while the soldering quality of lead-free solder was generally unacceptable in the manual or semi-automatic process under different temperatures. This result indicates that the soldering process with lead-free solder still needs to be further improved. It was also found that most cracks were formed on the interface between the solder and the silver paste and then expanded outwards.
188
Authors: Lin Li
Abstract: This paper gives a detailed description of the project on computer-assisted oral English test conducted in Wuhan Polytechnic University. The project indicated the advantages of computer-assisted oral English testing over face-to-face spoken English test, as well as weak points and problems to be discussed. At the end of this paper, some tentative suggestions are made on how to conduct large-scale computer-assisted oral English test with both high reliability and validity to develop students oral English ability in universities and colleges in China.
4494
Authors: Guang Yan Zhao, Yu Feng Sun, Gang Zhao
Abstract: Storage performance attribute parameter is a direct reflection of performance deterioration during storage process of missile-borne product, and is a key index for determination of missile storage period and storage reliability. Under the circumstance that it is difficult to deduce performance parameter directly from storage failure mechanism at present, starting with product function signal, this article combines fault mode mechanism effect analysis and function signal relevancy modeling analysis by using expert experience, so as to determine storage performance attribute parameter of product. Finally, a typical amplification circuit is used for application verification of above mentioned methods.
1087
Authors: Wae Gyeong Shin, Soo Hong Lee, Young Sik Song
Abstract: Reliability of automotive parts has been one of the most interesting fields in the automotive industry. Especially small DC motor was issued because of the increasing adoption for passengers’ safety and convenience. For several years, small DC motors have been studied and some problems of a life test method were found out. The field condition was not considered enough in the old life test method. It also needed a lot of test time. For precise life estimation and accelerated life test, new life test procedure was developed based on measured field condition. First, vibration condition on vehicle and latent force on fan motor shaft were measured and correlated with each other. Second, test condition was decided by obtained data. Finally, life of fan motors was estimated by new life test method in shorter test time.
1539
Authors: Fang Liang Dong
Abstract: Fuzzy Structure; Fuzzy Parameters; Reliability; Membership Function Abstract. This paper takes the fuzzy mathematics' reliability analysis as study object, has conducted the research to the fuzzy parameter system's reliability; comparing with traditional reliability analysis, obtained more precise fuzzy reliability confidence interval formula and carried on the proving based on cascade system, which has solved the computation complexity and the low precise problem in the tradition fuzzy reliability analysis's mass fuzzy operation. Method in the paper has certain promotional value in the fuzzy problem's research. It solved some problems such as the traditional fuzzy reliability analysis in the mass caused by the calculation of fuzzy computing complexity and low-precision. The emphasis of the article is divided into two parts: One is analysis and discussion on traditional module reliability analysis method and the fuzzy number membership function; the other one is proposing one new fuzzy parameter reliability analysis method and the conclusion, based on the former analysis.
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