1011 research outputs found
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Mechanism of water droplet flotage on water serface
Get PDFpublisherStructure of single bubble is classified into six types. Although bubbles are often seen in everyday life, a couple of types, a water droplet drifting on water surface and an anti-bubble, that is water droplet wrapped with air film, are regarded as unfamiliar phenomena. Mechanism of the air film stability is discussed in comparison with soap film stability. This paper presents a possible mechanism that sliding and rotation of a water droplet stabilize floating droplet and anti-bubble with preventing air films from losing their thickness. Transpoting air by capillary wave on the droplet surface is also a candidate of the stabilization mechanism. Step-by-step decrease of diameter in collapse of a droplet is explained by the concept of capillary wave.departmental bulletin pape
Performance Evaluations of SiC Power Device
Get PDFpublisherNowadays, most of power devices used in switching converters are Si devices. But recent years, novel power devices such as SiC diodes became to be in pratical use. In this studey, the aouthors measured and evaluated the switching chaacteristics of SiC-SBD(Shottkey Barrier Diode) device. From the experimental results, switching loss of SiC-SBD is much less than that of the fastest Si diodes. And the authors porpose the most suitable applications of Sic-SBD.departmental bulletin pape
Consideration of Information Ethics based on a Case Study
Get PDFpublisherThe importance of information ethics increases as informationization of the public at rapid progresses. In this paper, we discuss features of information ethics based on a case study. Through an examination of the Winny case, we clarify uniqueness of information ethics and some points that information engineers should note.departmental bulletin pape
Construction of an IPv6 Network Administration Tool
Get PDFpublisherIt is necessary to solve a lot of problem to shift from an IPv4 network to an IPv6 one. We construct an administration tool that reduced a management load according to IPv6 complexity while maintaining an operation policy of an IPv4 original network. The administration tool is constructed by using all open source at a low cost. We report here a purpose of the tool, details of operation, developed CGI programs and an evaluation of tool effect.departmental bulletin pape
Development of an Equivalent Test Circuit for High-voltage and High-current Semiconductor Devices
Get PDFpublisherHigh-voltage and high-current semiconductor devices such as 8kV-3500A thyristor and 5200V-2000A IGBT are developed and becoming commercially available. It is essential to evaluate and examine the characteristics of the devices before actually apply these devices to the large capacity equipment such as high-voltage dc(HVDC) transmission systems and static Var compensators(SVC). However testing of the devices under the actual circuit configulation requires a lot of cost and power. Then we propose an equivalent test circuit using a simple L-C oscillation circuit. We developed a test circuit capable up to 20kV and 500A and the design concept and brief test results are presented.departmental bulletin pape
Study of Small Airship Bird's Eye Viewer
Get PDFpublisherThe purpose of this research is to develop a surviellance / diagnostic system using a small airship which can check the state of the ground and the soundness of public facilities from a height of 10m-100m above the ground. In order to observe the ground from above satisfactorily, an airship must be held stationary in position above the ground. However, as a small airship has a comparatively large hull, but is lightweight, so it is difficult to control its position against any wind. This research aims to develop the position control system to keep an airship at a fixed point in wind conditions of about 3m/s.
Four different types of airship (3m-5m) have been developed since 2002. Here, the outline of each of these small airship types, and advanced content of the relevant research results about a position and attitude control system are presented. The bird's eye viewer system was conducted successfully from a height of 200m or more above the ground, and the fundamental design method of a simple ground observation system was established. However a better position and attitude control system is needed to make the practical use of ground observation from a small airship complete.departmental bulletin pape
Adsorption-Desorption of Argon for Graphitized Carbon Black
Get PDFpublisherThe adsorption-desorption isotherms of Ar at 77K were measured for the graphitized carbon black, Graphon, as well as its original carbon black. The Type Ⅱ adsorption isotherm of the original carbon black turned to an adsorption isotherm with the JE step after the graphitization. Each adsorption isotherm coincides with its desorption isotherm: there is no hysteresis in the adsorption-desorption cycle for both samples. The fitting of the Freundlich equation was tried and its parameters were obtained. The pore size distribution changed drastically after graphitization.departmental bulletin pape
Hardware Course Experiments in Information Technology Department of Tsuyama National College of Technology and Other College
Get PDFpublisherIn this paper, authors describe a hardware course experiment in information technology department of Tsuyama National College of Technology. And also they a recent hardware experiments in other colleges.departmental bulletin pape
A Tree Simulation on Personal Computer
Get PDFpublisherA technology of computer graphics advanced in recent years. As one of applications of computer graphics, there is a town view simulation. Tree shape are needed as one of components in these simulation. The paper describes how to generate tree shape on PC. By adopting the algorithm of L-system proposed by Dr. Lindenmayer, the program is developed and can generate various types of trees. Generated trees are almost close to a natural tree and can be expected to use in a computer graphics application.departmental bulletin pape
Iterated Hochschild Homology and Iterated Cyclic Homology of Polynomial Algebra
Get PDFpublisherA minimal Sullivan model for the odd dimensional sphere S(2n-1) is given by the differential graded algebra Λ(α) together with the trivial differential, whereα=2n-1. Sinceαis odd, Λ(α) is the exterior algebra generated by a single element α. The author determined the iterated Hochshild homology HH{l}*(Λ(α),0) and the iterated cyclic homology HC{l}*(Λ(α),0) of the complex (Λ(α),0) for the iteration degree l=1,2. Let K be an arbitrary field of characteristic zero. In this paper, where the caseα=2n, that is, the complex is the polynomial algebra K[α] over K, we compute the homologies HH{l}*(K(α),0) and HC{l}*(K(α),0). The complex (K(α),0) is a minimal Sullivan model for the infinitely dimensional complex projective space or the classifying space CP∞=BU(1) forα=2, and the classifying space BSU(2)=BSp(1) forα=4. Therefore we can obtain the explicit forms of the cohmologies H*(map(T(l),X);K) and H*(E(T)×(T)map(T(l),X);K) of the mapping space map(T(l),X) and the Borel construction E(T)×(T)map(T(l),X) for X=CP∞=BU(1), BSU(2)=BSp(1), where T is the circle and T(l)is the l-dimensinal torus.departmental bulletin pape