1,721,071 research outputs found
Fabrication of arbitrarily shaped microelectrodes by electrochemical etching
No full textSome conventional machining methods have been developed to machine microelectrodes. However, these methods still require too much time and too many resources. This paper uses electrochemical etching as an alternative method for the simple and cheap fabrication of microelectrodes. Electrochemical etching is usually considered an appropriate method of producing sharp probes. However, it is possible for the entire shape of an electrode to be controlled under certain conditions such as the immersed length, the applied current, and the etching time. After developing a method to estimate the electrode shape, we produced some electrodes by generating etching conditions. Stepped and punch shapes were fabricated. These have applications in the manufacturing of operation utensils, measurement tips, and machining tools.This work was supported by the Center for Ultramicrochemical
Process Systems (CUPS)
Reduction of seek time of tracking actuator with pulsed excitation in optical disk
No full textTime consumption during the track seek is an important factor which indicates the ability of an optical disk system. In a two-stage tracking actuator, latency time exists before the laser beam follows the destination track because of the vibration of the fine actuator. Modified velocity profiles and control techniques for the actuator have been proposed to reduce the latency time. When a fine actuator is locked to the coarse actuator, another latency time caused by the disk eccentricity cannot be reduced. It becomes possible to forecast the eccentricity as the rotation type of the optical disk changes to constant angular velocity (CAV). Thus the latency time can be reduced by excitation of the fine actuator with the same velocity of the track when the coarse actuator stops. Pulsed excitation is used for the excitation. This method is applied to a compact disk read-only memory (CD-ROM)
Fabrication of tungsten micro-punch for micro-nozzles
No full textA very thin electrode with a tapered shape and a cylindrical tip, named ultrathin punch, is fabricated by electrochemical etching and by controlling the vertical position of the electrode during etching. We used electrochemical etching by which we obtain punches quickly and simply. The fabrication procedure and its results are presented in this article. With this punch, we can get holes or nozzles for ink-jet printers, textile machines, and other uses. Various angles of the taper can be obtained by adjusting the immersion depth. The tip diameter also can be controlled by adjusting current density and etching time. (C) 2001 American Institute of Physics
Monitoring of cylindrical rod tension force under varying temperature using acoustoelastic effect
No full textThis paper presents the development of a tension force monitoring technique based on bulk wave and acoustoelastic effect for a cylindrical rod in the suspension bridge anchor system under varying temperature. First, a cylindrical rod specimen is fabricated, and macro fiber composites transducers are installed on the specimen. Then, the bulk waves are measured under various tension force levels and temperature conditions. The measured bulk waves are used to estimate the tension force level after compensating the temperature effect. The performance of the developed technique is examined using test data. The uniqueness of the developed technique includes (1) tension force estimation of the mock-up specimen of the real bridge using the acoustoelastic effect and (2) temperature compensation on the tension force monitoring without temperature measurement. © 2021 IABSE Conference, Seoul 2020: Risk Intelligence of Infrastructures - Report. All rights reserved
Fabrication of cylindrical micropins with various diameters using DC current density control
No full textAn electrochemical method is shown to fabricate extremely thin cylindrical tungsten micropins. The cylindrical micropin is obtained by regulating the current density. The current profile for the current density control is obtained with a mathematical model based on the relationship between an electric charge and a surface area. (C) 2003 Published by Elsevier Science B.V
High speed JPEG coder based on modularized and pipelined architecture with distributed control
No full textThe design of an efficient reusable IP based Extended JPEG encoder is presented in this paper. This encoder uses user-defined quantization and Huffman tables that can be reconfigured at run-time. It has a modularized and pipelined architecture with distributed control for each block. A simple interface makes integration of the modules in various systems simple and straightforward. The design when targeted on FPGA operated at speed of up to 90MHz and when mapped on 0.251 mu m CMOS process the design can operate at speeds over 450MHz, which is faster than any of the similar JPEG encoder designs reported
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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