• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.2
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• pp.8-16
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• 2011

It is hard and complicated to analytically derive the volumetric-displacement formula of a gerotor pump/motor. Analytical formulas for calculating the volumetric-displacement are derived in this work, which is relatively easy and based upon vane lengths. The vane lengths mean the distances from axis of inner rotor or outer rotor to contact points between inner and outer rotors. Two kinds of formula were studied for two different kinematic motions of rotors. The first one is the case that outer rotor is fixed in space and inner rotor is in mixed motion of planetary revolution and rotation with respect to the spinning axis. And the second is the case that both inner and outer rotors simultaneously rotate. The proposed formula is verified through comparison with volumetric-displacement obtained from numerical CAD calculation.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.1
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• pp.27-32
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• 1988

Electron Spectroscopy for Chemical Analysis(ESCA) allowes the determination of the elemental composition and the bonding state of the surface atomes in the interface between two materials. In the binding energies of ESCA spectrum, there are zero error, voltage scaling error and random error. Accurate analysis of the intensity energy response functions and accurate calibration of the energy scale are essential to use X-ray photoelectron spectron meter. At the results of the calibration of the ESCA spectra in the copper and cordierite (Mg2Al4Si5kO18) interfaces, the errors relative to the copper are -3.03 eV for the zero error -z,-197 ppm for the voltage scaling error -V and 6.9 meV for the random error -R. The method of the calibration is able to apply for the binding energy calibration of the another ESCA spectra.

• The Korean Journal of Rheology
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• v.2 no.1
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• pp.67-78
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• 1990

세라믹 분말의 사출성형성을 평가하기 위하여 다양한 혼합체 시스템에 대한 혼합도 와 유변학적 성질을 질화규소 미세분말의 부피비를 변화시키면서 조사하였다. 열가소성 결 합체 시스템은 폴리에틸린 폴리에틸렌 왁스 그리고 미소량의 첨가제를 혼합하여 사용하였 다. 혼합성능을 평가하기 위하여 비분산혼합에서는 총접촉면적비를 그리고 분산혼합에서는 총파괴표면적비를 혼합척도로서 사용하여 정성적으로 모형화하였다. 사용된 혼합기내의 유 동장을 해석하기 위하여 뉴우톤유체를 가정하여 유동해석을 수행하였다. 혼합물의 혼합도는 각각 5분 30분 동안 혼합된 시편을 주사전자현미경 사진에 의해 관찰하여 평가하였다. 또한 혼합물의 사출성형성 그리고 혼합질 점도 토우크 곡선 사이의 관계를 규명하기 위하여 전단 변형를 속도를 따른 점도를 모세관 점도계를 사용하여 측정하였으며 질화규소의 부피비가 60%일 때까지는 만족할 만한 성형성과 혼합질을 가짐을 알 수 있었다.

• Congress of the korean instutite of fire investigation
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• 2010.12a
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• pp.239-248
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• 2010

2008년도 사고설비별 전기화재 발생현황을 살펴보면 전기화재중 전기배선 및 배선기구에서 발화한 화재가 2,540건으로 전기화재 발생 중 25.95 %를 점유하였다. 또한 사고전압별 전기화재 발생현황으로 220/380 V에서 화재가 6,320건(64.4 %)으로 전기화재의 대부분을 점유하였다. 전기화재는 단락, 과전류, 접촉불량, 트래킹 등 9가지로 분류할 수 있다. 이러한 전기로부터 재해를 막기 위하여 누전차단기나 배선용차단기를 사용하여 일부의 전기화재 원인을 차단할 수 있으나 차단기 자체에서 발생하는 원인에 대하여는 보호할 전기기기가 부재하다. 본 논문에서는 최근 실화법의 적용으로 일반적으로 전기화재로 취급되어지지만 보다 세밀히 조사하면 제조결함, 사용자 부주의, 설치 및 환경에 따른 위험성을 분석하고 전기설비에서의 화재 발생에 대한 예방대책에 활용할 수 있도록 연구하였다.

• Journal of the KSME
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• v.25 no.4
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• pp.320-326
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• 1985

지난 10여년간의 연소분야에 대한 연구는 크게 세가지 방향에서 괄목할 만한 발전을 이루어 왔다. 그 첫째는 대용량 컴퓨터의 개발에 따른 수치해석능력의 신장을 들 수 있고, 둘째는 실 험에서 레이저를 이용한 비접촉 계측방법의 발달을 들 수 있다. 또한 이론적 관점에서는 1974 년이래 유체역학에서 프란틀의 경계층 이론에 비견될 수 있는 접합점근방법(matched asymptotic technique)를 이용하여 예혼합 화염의 전파속도, 확산화염의 구조 및 점화/소화현상, 열폭발문제, 화염의 안정성 등에 관한 엄격한 해석이 가능하게 되었다. 이로서, 종래의 현상적, 물리적 설 명으로 이해될 수 없었던 분야를 해석할 수 있었다. 이에 따라 본 강좌에서는 연소분야의 이 론적 연구에 초점을 맞추어 접합점근방법의 기초개념 및 해석방법을 소개하고자 한다. 이를 위해 2장에서 확산 화염과 예혼합 화염의 특성을 설명하고, 3장에서 화염면 극한의 해석, 4장에서 확산 화염의 구조해석을 통한 점화/소화현상 및 5장에서 예혼합 화염에의 응용 등을 소개한다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.5
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• pp.601-610
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• 1986

The acoustic intensity in the very near field of a vibrating surface reveals information about the location of sound sources and sinks. A system model of tennis racket was developed from simultaneous measurement of excitation force, surface vibration and the near field sound pressure. The characteristics of structural dynamics were obtained by standard experimental modal analysis techniques while the sound radiation characteristics were determined by estimating the acoustic intensity. In this paper, the information about vibration behviour was obtained by acoustic intensity method and some, experiments for verification were carried out. Close correlation was found between experimentally determined acoustic intensity and vibration mode patterns of the tennis racket.

• Proceedings of the KACD Conference
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• 2003.05a
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• pp.288-288
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• 2003

1960년대 중반부터 도입된 구치부 복합레진 수복은 복합레진과 접착시스템의 향상된 물성 때문에 구치부 사용에 대한 주목할 만한 결과를 보고하고 있다. 현재는 다수의 1급, 2급 수복물에 복합레진이 적응증으로 기술되며, 사실상 미국치과의사 협회(ADA)도 초기와 중등과 크기의 병소를 보존적 I, II급 와동으로 형성된 뒤 복합레진으로 수복하는 시술의 적절성을 인정하고 있다. ADA는 "복합레진을 유치나 영구치의 I급, II급, V급 수복에 올바르게 적용하면 아발감의 수명에 뒤지지 않는다."라고 기술하고 있다. 이에 본 강연에서는 I급과 II급 복진레진 수복을 위한 관련된 재료들의 특성과 단점들을 극복하기 위한 노력들을 설명하고자 한다. 특히 중합수축과 관련된 문제점들을 해결하기 위해 제시되고 있는 방법들의 임상적 적용 가능성의 한계와 술후 과민증을 줄이기 위한 방법, 그리고 구치부에 적용된 레진들의 마모를 줄일 수 있는 방법들을 모색하고 한다. 더불어 구치부 복합레진 수복을 위한 임상 시술 시 가장 흔하게 발생되는 단조로운 인접면 외형 형성 및 접촉점 개방의 문제점을 인식하고 이를 막기 위한 노력 및 기구들의 사용 조작에 대해 토의해 보고자 한다.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.281-290
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• 2018

The purpose of this study is to investigate hospital nurses' attitude toward migrant wives, the nurses' cultural knowledge, and their cultural nursing behavior, to analyze the relations between them, and to find the factors influencing their cultural nursing behavior. A questionnaire was given to 161 nurses in two general hospital in S city from April 1 to April 30, 2017. The results were evaluated by the SPSS/SIN 21.0 program. As a result, the hospital nurses' attitude toward immigrant wives scored 2.70 out of 4 points; cultural knowledge 0.51 out of 1 points; their cultural nursing behavior 3.04 out of 5 points. Cultural nursing behavior has significantly positive correlation with their cultural knowledge. Cultural knowledge, religion, and position in hospital were found to be the factors influencing their cultural nursing behavior. These influential factors explained their cultural nursing behavior 20.9%. In order to improve hospital nurses' cultural nursing behavior, it is necessary to provide continuous multi-cultural education to improve their knowledge, and to offer various convergence programs to give them more opportunities to interact multi-cultural persons.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.31-37
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• 2009

A zwitterionic surfactant shows not only detergency but also mildness effect since it shows characteristics of a nonionic or an anionic surfactant above an isoelectric point, while showing characteristics of a cationic surfactant below an isoelectric point. Therefore, a zwitterionic surfactant can serve as a dual function surfactant by a single molecule through the interconversion of cleaning and softening effects depending on pH variations of the aqueous solution. In this study, physical properties of betaine surfactant such as CMC, surface tension, interfacial tension, contact angle and viscosity were measured and phase behavior study was performed. Also dual function characteristics of betaine zwitterionic surfactant were investigated by measuring an isoelectric point using QCM(quartz crystal microbalance) and zeta potential measurement. The CMC of betaine surfactant was near $10^{-4}mol/L$ and the surface tension at CMC was about 32 mN/m. The interfacial tension between 1 wt% aqueous solution and n-decane measured by spinning drop tensiometer at pH 2~10 resulted in an increase in interfacial tension until pH 5 and a decrease with pH after 5 and equilibration time showed the similar trend with an increase in pH. The isoelectric point of betaine surfactant measured by QCM experiment was found to exist between 3.0 and 3.3, which is the same as the result determined by zeta potential measurement.

• Analytical Science and Technology
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• v.28 no.4
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• pp.288-298
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• 2015

A distribution study of glitter was conducted from a local university building. The potential recipient surfaces chosen were the 1,000 chairs kept in 16 separate classrooms of the building. The surface of chairs contacting with buttocks and back of users were tape lifted with commercial adhesive tapes, and the surface of adhesive tapes were examined with a stereomicroscope to locate the glitters. 12 glitter particles were found from 11 chairs kept in 16 classrooms of a building. This result indicates that the possibility of glitter finding from Korean violent crime scene is high. The 12 glitters found from the chairs were analyzed with a stereomicroscope and an FTIR spectrophotometer to find the matching glitter. The stereomicroscope was used for the observation of the shapes, dimensions, colors and holograms of each glitter, and the FTIR spectrophotometer was used for the analysis of the chemical composition of the coating material of each glitter. The examination results revealed that 8 glitters out of 12 glitters were not sharing the common origin each other. Also, two glitters found from two separate classroom chairs share common microscopic and FTIR spectroscopic characteristics which indicating two glitters share common origin. The record of the students who had used the classrooms was traced and the authors could find that the classrooms where the same glitters were found were shared by a group of students who listen to the same class. This result implies that the path of the involved people should be considered while assessing the value of trace evidence.