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이동통신 단말기용 일체형 마이크로스피커의 해석 및 성능 향상 설계
황건용,이원열 영산대학교 2003 영산논총 Vol.11 No.-
In mobile telecommunication devices of multimedia era, micro-speakers of high quality sound are essential parts to generate human voice in speaker phone and MP3 song player. In this paper, for the performance improvement of integrated micro-speaker, a complete analysis of a micro-speaker considering mechanical, electrical and magnetic coupling effects was performed using finite element method and its validity was confirmed as well by experiments. Through electromagnetic field analysis, 2D FEM model was implemented to calculated electromagnetic force that excites diaphragm. For the prediction of acoustic characteristics of diaphragm, free and forced vibration analysis considering coupling effect was performed and confirmed by experiments.
유한유소법을 이용한 이동통신 단말기용 마이크로스피커의 성능 분석
황건용 영산대학교 2002 영산논총 Vol.10 No.-
In mobile telecommunication devices of multimedia era. microspeakers of high quality sound are essential parts to generate human voice in speaker phone and MP3 song player. For SPL analysis of microspeakers, magnetic force acting on the voice coil is determined by Lorentz law and electromagnetic FEM analysis. Harmonic analysis of diaphragm vibration and acoustical analysis are also followed using FEM to determine surface velocity of the diaphragm and sound pressure level. Noting that magnetic flux linkage is affected by vibrating voice coil, coupling between mechanical and magnetic analysis should be also considered. For performance comparison between inner and outer PM type microspeakers, specific parameter is chosen to change the excitation position and magnet volume. With the decreased the parameter of the outer type, magnet volume is increased to produce higher SPL and the first resonant mode of the diaphragm is more efficiently excited due to concentrative excitation, resulting in lower and broader frequency range. Therefore, it can be said that the outer PM type mcrospeakers are more advantageous to generate human voice frequency that is essential for multimedia function.
황건용(Hwang, Gun-Yong),황상문(Hwang, Sang-Moon),권중학(Kwon, Joong-Hak),김광석(Kim, Kwang-Seok),이홍주(Lee, Hong-Joo) 한국소음진동공학회 2006 한국소음진동공학회 논문집 Vol.16 No.10
With the growth in electronics and the remarkable advance in wireless communication technology, mobile devices, such as mobile phones and PDAs are incessantly improved in their diverse functional performance. Lighter weight and smaller size has been gradually accomplished by recent circuit integration technology resulting in rapid growth in the number of mobile phone subscribers. Driven by customer demand, recent mobile devices are fully capable of realizing a variety of dazzling multimedia effects powered by electro-acoustic parts that have become one of the generic components. However, This paper also presents an oval micro-speaker, that is' expected to show an excellent performance within limited space of mobile phone, and its performance design has been suggested as well. Finally, a statistical approach to achieve high characteristic and performance is suggested by Taguchi method to identify a certain relationship between a mobile phone and a micro-speaker.
소형 제품 조립의 작업 효율 향상을 위한 취약 등급 분류 체계
목학수,황건용 한국경영과학회 1998 한국경영과학회 학술대회논문집 Vol.- No.1
In this paper, it is presented the method for rising assembly efficiency in production of a small-size product. For this, it is selected the influence factors of assembly system, and tables of weak grade are composed for classification of weak degrees. Each process is subdivided into requisite works, and the checklist to the requisite work is made for evaluation of assembly efficiency. For the process which assembly efficiency is low, on the basis of assembly productivity improvement, it is derived alternatives related to weak points. After review of alternatives, it is applied to the actual assembly process.
ISO 9001 품질경영시스템과 제품안전경영시스템의 커플링을 통한 진보된 핵심성과지표의 개발 - 중소 제조업 사례 중심으로 -
박국제,이운식,황건용 한국경영공학회 2008 한국경영공학회지 Vol.13 No.2
It is important to manage quality and safety of a product for coping with fast-paced world effectively. This paper demonstrates a coupling model between ISO9001 Quality Management System and Product Safety Management System. And the paper presents a method which decides key performance indicators (KPI) to be concentrated on the effectiveness of system operation. An case study shows an process for industry to implement the developed methodology .
Effect of the number of poles on the acoustic noise from BLDC motors
김광석,이창민,황건용,황상문 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.2
The goal of this study is to examine the effect of the number of poles on the noise from BLDC motors. To this end, the number of slots was fixed to six and the number of the poles was set to four or eight before noise was measured. Motors having different numbers of poles showed clear differences in noise; cogging torque, torque ripple and normal local force were interpreted, analyzed and compared to determine the reason for the differences. To conduct precise comparisons of noise, efforts were made to prevent changes in other variables when constructing the four-pole and eight-pole motors. Noise measurements were conducted after going through the above preparation. The results show that the eight-pole motor produced a lower noise level than the four-pole motor. To determine the cause of the noise, the cogging torque, torque ripple and radial local force were calculated, which are representative noise sources in BLDC motors,and FFT was performed to analyze their frequency components (harmonics). The calculations were made using a finite element method with the Maxwell stress tensor.
냉각계통 동적 예측을 위한 수전해 시스템 동적 모사 모델
윤상현,윤진원,황건용 한국수소및신에너지학회 2021 한국수소 및 신에너지학회논문집 Vol.32 No.1
Water electrolysis technology, which generates hydrogen using renewable energy resources, has recently attracted great attention. Especially, the polymer electrolyte membrane water electrolysis system has several advantages over other water electrolysis technologies, such as high efficiency, low operating temperature, and optimal operating point. Since research that analyzes performance characteristics using test bench have high cost and long test time, however, model based approach is very important. Therefore, in this study, a system model for water electrolysis dynamics of a polymer electrolyte membrane was developed based on MATLAB/Simulink®. The water electrolysis system developed in this study can take into account the heat and mass transfer characteristics in the cell with the load variation. In particular, the performance of the system according to the stack temperature control can be analyzed and evaluated. As a result, the developed water electrolysis system can analyze water pump dynamics and hydrogen generation according to temperature dynamics by reflecting the dynamics of temperature.