409 Stainless steel muffler의 pitting corrosion 발생 원인 규명

서도수,송용화,김흥식 울산대학교 2002 공학연구논문집 Vol.33 No.2

머플러의 재질은 배기 온도의 고온화와 배기가스 정화 시스템 부착에 따른 내열성 및 내식성이 우수한 재료가 요구되며, 현재 사용 중에 있는 배기계용 재료에는 알루미늄 도급 강판, 스테인레스 409L, STS 436 등이 있는데, 각 재료는 품질 특성 및 수명이 고려되어 배기계 재료의 여러 부위의 요구 조건에 맞게 선택되어 적용되고 있다 경제적인 이유로 인하여 스테인레스 409L을 많이 사용하고 있는데 일부 차종에서는 단시간내에 안쪽 부분에서 피트(pit)가 발생하여 관통되는 사례가 빈번하게 발생되고 있는 실정이다. 따라서, 본 연구에서는 머플러의 부식원인을 규명하기 위해 부식이 진행되어 관통되어진 소음기를 수거하여 FE-SEM으로 관찰분석하고, 409 스테인레스 강을 염수분무실험을 통하여 소음기 부식원인을 규명하였다.

전어의 보존중 겨자의 처리 효과

서권일,강갑석,이용수,정용진,김용택,심기환 동아시아식생활학회 1996 동아시아식생활학회지 Vol.6 No.2

Effects of mustard seed(Brassica juncea) on the preservation of raw gizzard-shad slice were investigated, morphological change of Vibrio parahaemolyticus treated with water-extract of mustard seed was examined, the results are as following. The pH of raw gizzard-shad slice soaked in water with mustard seed slightly increased during preservation, and the pH was in inverse proportion to the added amount of mustard seed. The number of bacteria and Vibrio of raw gizzard-shad slice treated with mustard seed were lower than control, and the higher the mustard seed concentration, the lower the number of bacteria and Vibrio. The TMA-N content of raw gizzard-shad slice gradually increased during preservation, and the TMA-N was in inverse proportion to the added amount of mustard seed. Scanning electron microscopy of Vibrio parahaemolyticus treated with water extract of mustard seed showed that surface membrane was destroyed with expended ellipsoidal shape.

궤도 차량의 기동성능 예측 프로그램 개발

서정길,김종수,김용태,이경식,한성현 한국공작기계학회 2004 한국공작기계학회 춘계학술대회논문집 Vol.2004 No.-

In this paper, we developed a Windows XP version off-line programming system which can simulate a track vehicle model in 3D graphics space. The track vehicle was adopted as an objective model. The interface between users and the off-line program system in the Windows XP's graphic user interface environment was also studied. The developing language is Microsoft Visual C++. Graphic libraries, OpenGL, by Silicon Graphics, Inc. were utilized for 3D Graphics.

유도전동기 운전을 위한 외란상쇄 상태관측기 설계

서영수,송호빈,김용주 明知大學校 産業技術硏究所 2003 産業技術硏究所論文集 Vol.22 No.-

Abstract - This paper described a robust control of an induction motor using a disturbance cancellation observer of a feedforward control with Matlab simulink. The speed response of conventional PI controller characteristics is affected by variations of load torque disturbance. In the proposed system, the speed control characteristics using a feedforward control isn't affected by a load torque disturbance.

용융 알루미늄 도금 강재의 부식 특성

서도수,송용화,김흥식 울산대학교 2002 공학연구논문집 Vol.33 No.2

용응 알루미늄 도금방법으로는 피도금물을 산세에 의해 피도금물 표면의 유지 또는 산화물을 완전히 제거한 것을 용응알루미늄속에서 일정시간 동안 침지시키면 철강표면에 철과 알루미늄과의 합금층이 생기며 그 합금층 위에 알루미늄이 부착 도금되는 것이다. 본 연구에서는 용음알루미늄 도금강재의 부식 특성을 평가하기 위해 염수분무시험을 실시하여 표면을 관찰하므로서 해수에서 용응알루미늄 도금 강재를 적용할 경우 내부식성을 평가하였다.

전류평형 제어기를 부가한 IGBT 모듈의 모델링

서영수,송호빈 명지대학교 산업기술연구소 2001 産業技術硏究所論文集 Vol.20 No.-

Due to tolerances of semiconductor, gate-drive and mechanical parameters the total load current is not shared equally between paralleled IGBT power modules. In this paper, a closed loop control is presented to balance the current in a gate-drive circuits. The theoretical assumptions have been verified through SIMULATION with PSPICE.

주사전자현미경을 이용한 온실가루이(Trialeurodes vaporarium) 성충 부속지의 외부 미세구조 관찰

서미자,김기덕,김남성,박수진,채순용,윤영남 충남대학교 농업과학연구소 1999 농업과학연구 Vol.26 No.2

온실가루이의 외부형태적 특징을 주사전자현미경 사진을 통해 관찰하였다. 우선 이들은 포탄모양의 알을 산란하는데 짧은 갈고리모양의 구조에 의해 잎 뒷면에 붙어있는 것이 확인되었다. 촉각의 길이는 0.3㎜로 전체가 6마디로 구성되어 있고, 첫마디는 굵고 짧으며 둘째 마디부터 가늘고 긴 채찍모양을 하고 있다. 끝마디인 6번째 마디의 끝에는 길이가 10㎛정도의 가늘고 비교적 긴 감각기를 가지고 있어 기주를 탐색하는 과정에서 식물체의 표면을 탐지하는데 사용하는 것으로 사료되며, 바로 밑부분에는 길이가 7-8㎛정도의 비교적 굵은 감각기 2개가 존재하고 있는 것으로 확인되었다. 이 감각기는 반대편에는 존재하고 있지 않은 비대칭 분포를 보이고 있으며, 또한 두개의 모양이 서로 상이함으로 볼 수 있다. 이들의 기능은 주로 기주식물을 탐색하거나 후각기능의 화학적 감각기의 역할을 하는 것으로 추정할 수 있다. 섭식행동이 이루어지는 온실가루이 구기는 전형적인 piercing-sucking type으로, 구침이 길게 잘 발달되어 있다. 구기의 끝부분은 10여개의 미세감각기가 분포고 있어 식물체 표면을 탐색하고 맛을 보는 미각기능을 하고 있으리라 추측할수 있다. 구침은 종종 구기에서 분리되기도 하지만, 구침을 잡아주는 지지대가 기부쪽에 자리하고 있음을 알 수 있다. 구침은 두 개의 반원형이 붙어 있는 형상을 하고 있으며, 다른 흡즙형 구침과는 달리 톱날모양의 구조를 볼 수 없었다. 한편 온실가루이의 다리 끝에 붙어 있는 발톱은 식물체에 고정시키기 위한 구조로 보이는 두 개의 갈고리 형태의 발톱과 그 사이에 중앙지지대 형태의 구조인 paranychium을 포함하여 3갈래의 구조를 하고 있다. External morphology characteristics of the greenhouse whitefly, Trialeurodes vaporarium were investigated by scanning electron microscopy. The antennae of the greenhouse whitefly was 6 segments, rod-shape, and 0.3mm length. On the 6th segment, there were many sensilla for searching host-plant as olfactory receptor. The mouthpart of the greenhouse whitefly was a piercing-sucing type, then its stylet was well developed for piercing plant leaf tissue. Claw of the foreleg was a 3-war hook shape including paranychium for attaching plant surface to pierce and lay egg.

FeCoB계 아몰퍼스 자성박막의 임피던스효과에 관한 연구

서강수,정승우,임재근,신용진 명지대학교 대학원 1997 대학원논문집 Vol.1 No.-

In this paper, we has studied frequency dependence of impedance of FeCoB amorphous magnetic films. First, we investigated optimal composition and sputtering conditions for fabrication of zero magnetostrictive amorphous magnetic films. (Fe_(1-x)Co_x)_79Si_2B_19 was selected as the basic composition and then, the films were fabricated with x=0.94 and 0.95 respectively by using sputtering method at high frequency. In order to relieve the internal pressure and derive the magneto-anisotropic. we annealed the films in about 150[Oe] of magnetic field and in the range(280℃, 300℃ and 320℃ respectively) of crystallization temperature(360℃). In addition, we annealed the films under non-magnetic field and near crystallization temperatures (283℃/30min, 400℃/30min and 400℃/1hr respectively) in order to decrease magnetoanisotropic. Then, we investigated magnetic properties including magneto-impedence and inductance. As the results, we found excellent magnetic characteristics and high impedence changing rate(4.52[%/Oe]) when we fabricated a sample under the condition that input power 400[W], Ar gas pressure 6.4[mTorr]. sputtering time 30[min] and annealing time 30[min] at 300[℃] in 150[Oe] magnetic field Especially, the impedence changing rate which was basic characteristic of Ml element was 4.52[%/Oe] for x=0.94. Moreover, the inductance values of the samples annealed at 400[℃/30min] were higher by 132[%] to 197[%] than those of the non-annealed samples. In addition, the quality factor Q was below 0.7 for all samples. Consequently, we find that the zero magnetostrictive amorphous magnetic film can be used as a magnetic sensor material.

Pyrantel Pamoate(Combantrin)에 依한 蛔蟲症의 減量療法

徐丙卨,李純炯,趙昇烈,姜信榮,梁龍石,黃邱一,朴定圭,李水月 中央醫學社 1973 中央醫學 Vol.25 No.4

The mass treatment trial with low dosage of pyrantel pamoate against Ascaris lumbricoides infection was conducted to school children in rural areas of Korea. A comparative trial in the use of piperazine salt, santonin-kainic acid complex in the treatment of ascariasis was also attempted to evaluate the efficacy of' pyrantel pamoate. A total of 804 Ascaris infected school children selected out of 822-positives, who were screened from the total 1, 699 collected specimens, were classified into 7 groups. One of the three kinds of anthelmintics, i.e., pyrantel pamoate, piperazine adipate and santonin-kainic acid complex was administered to each group according to the planned regimen. For the evaluation, the egg negative conversion rate(cure rate) and egg reduction rate were calculated 4 weeks after treatment on 623 follow-up cases with the obtained results from the stool examinations (Cellophane Thick Smear Method and Stoll's Egg Counting Technique). The results obtained were; 1. The egg negative conversion rate was the highest in pyrantel treated groups (Group 1, 2, 3), santonin-kainic acid complex treated group (Group 7) coming next, and the lowest in piperazine treated groups (Group 4, 5, 6). 2. The reduction rates were also obtained just as the same order of the above results. 3. Among the pyrantel pamoate treated groups, the low dosage groups (Group 2 8: 3) showed 90.6% and 85.7% of negative conversion rate, and 99. 2% and 98. 2% of reduction rate respectively, while 94.1% of negative conversion rate and 97.9% of reduction rate were obtained in the conventional dosage group (Group 1). 4. On the analysis of efficacy in the groups treated with piperazine adipate, the best results were. shown in 2 or 3 consecutively treated groups (Group 4 &.- 6) under the supervision of qualified doctors, and the worst was in the group treated with 2 consecutive administration by teachers without supervision (Group 5). 5. The side reactions were so negligible in all the trial groups that none of the treated cases complained about the known side effect of those anthelmintics. From the present study, it can be suggested that the pyrantel pamoate is the most effective among three drugs, and also be recommended to apply the low dosage schedule of pyrantel pamoate in the masstreatment of ascariasis to reduce the expense of masstreatment.

직류 전동기 속도ㆍ토크 제어를 위한 토크전류관측기 설계

서영수,김은기,김용주 明知大學校 産業技術硏究所 2002 産業技術硏究所論文集 Vol.21 No.-

In this paper, the load torque observer is designed for speed and torque control of dc motor. Load torque is very sensitive to the variation and disturbance of the input parameters. Also, there is a limitation to design the poles of speed and torque responses within PI controller parameters. Thus, a method is required to compensate the load disturbance without regulate the gain of the speed controller. The proposed system can accurately estimate the instantaneous speed even at the low speed range by using the load torque observer based on the torque component of DC motor The system becomes robust against disturbances using a feed-forward control of the load torque estimated automatically at the speed observer.