• 제목/요약/키워드: Loose Parts

검색결과 81건 처리시간 0.03초

선박용 판형 열교환기의 볼트풀림방지 및 수량최소화기법 개발 (Development of a Technique to Prevent Bolt Looseness and to Decrease in Quantity for the Plate Type Heat Exchanger Used in Large Craft)

  • 김호윤;배원병;장영준;한승무;김철
    • 한국정밀공학회지
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    • 제24권9호
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    • pp.44-51
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    • 2007
  • There are many methods to assemble various parts of a product, and one of them is the bolting system widely used in a industrial field due to the merits; easiness to obtain strong tightening force, simplicity of assemble or disassemble in order to repair, substitution or cleaning, and so on. But this bolting system needs attachments not to let a bolt loose and they are an important factor to cost a great deal. In this study, some equations are suggested and FE analyses are carried out to verify the cause of the bolt looseness occurring in the tightening process. And because the number of bolts in the bolting system has been decided by empirical know-how of designers in the field, safety rate in the plate type heat exchanger is often too high. Therefore the equations to decrease in quantity are suggested in consideration of the relationship between a critical shearing force acting on the screw and a normal force acting on the cooling plate by the working fluid.

A study on visual tracking of the underwater mobile robot for nuclear reactor vessel inspection

  • Cho, Jai-Wan;Kim, Chang-Hoi;Choi, Young-Soo;Seo, Yong-Chil;Kim, Seung-Ho
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.1244-1248
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    • 2003
  • This paper describes visual tracking procedure of the underwater mobile robot for nuclear reactor vessel inspection, which is required to find the foreign objects such as loose parts. The yellowish underwater robot body tends to present a big contrast to boron solute cold water of nuclear reactor vessel, tinged with indigo by Cerenkov effect. In this paper, we have found and tracked the positions of underwater mobile robot using the two color information, yellow and indigo. The center coordinates extraction procedures are as follows. The first step is to segment the underwater robot body to cold water with indigo background. From the RGB color components of the entire monitoring image taken with the color CCD camera, we have selected the red color component. In the selected red image, we extracted the positions of the underwater mobile robot using the following process sequences; binarization, labelling, and centroid extraction techniques. In the experiment carried out at the Youngkwang unit 5 nuclear reactor vessel, we have tracked the center positions of the underwater robot submerged near the cold leg and the hot leg way, which is fathomed to 10m deep in depth.

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A High-performance X/Y-axis Microaccelerometer Fabricated on SOI Wafer without Footing Using the Sacrificial Bulk Micromachining (SBM) Process

  • Ko, Hyoung-Ho;Kim, Jong-Pal;Park, Sang-Jun;Kwak, Dong-Hun;Song, Tae-Yong;Setaidi, Dadi;Carr, William;Buss, James;Dan Cho, Dong-Il
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.2187-2191
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    • 2003
  • In this paper, a x/y-axis accelerometer is fabricated, using the SBM process on a <111> SOI wafer. This fabrication method solves the problem of the footing phenomenon in the conventional SOI process for improved manufacturability and performance. The roughened lower parts as well as the loose silicon fragments due to the footing phenomenon are removed by the alkaline lateral etching step of the SBM process. The fabricated accelerometer has a demodulated signal-to-noise ratio of 92 dB, when 40Hz, 5 g input acceleration is applied. The noise equivalent input acceleration resolution and bandwidth are $125.59\;{\mu}g$ and over 100 Hz, respectively. The acceleration random walk is $12.5\;{\mu}g/\sqrt{Hz}$. The output linearity is measured to be 1.2 % FSO(Full Scale Output) at 40 Hz, and the input range is over ${\pm}\;10g$.

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원자력발전소 금속파편감시계통 센서 건전성 평가 (Evaluation Methode for LPMS Sensor of Nuclear Power Plant)

  • 조성한;정창규;김형관
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2011년도 제42회 하계학술대회
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    • pp.1816-1817
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    • 2011
  • 원자력발전소의 금속파편감시계통(LPMS : Loose Parts Monitoring System)은 원자로냉각재계통 내부에 존재할 수 있는 금속 이물질과 구조물 이완부에 의한 충격신호를 조기에 검출하여 원자로 구조물 및 핵연료 손상, 제어봉 구동장애 등을 미연에 방지하여 발전소 안전운전을 담당하는 중요 감시설비이다. LPMS는 금속 이물질이나 구조물 이완부에 의한 충격신호를 검출하기 위해 충격파에 민감한 가속도계를 원자로냉각재계통 중 금속파편이 자연적으로 모일 수 있는 각 구역의 표면에 최소 2개 이상 설치되어 있다. 원전은 규제요건에 따라 설비의 건전성 확인을 위해 24시간, 7일, 31일, 91일 마다 각 1회의 설비 건전성 시험을 수행하며, 계획예방정비기간 중에는 가속도계 주변에서 강구나 스프링 타격기를 이용한 충격시험을 통해 설비 전체의 건전성을 확인하고 있다. 설비 건전성 확인을 위해 경상운전 중에 수행하는 설비 건전성 시험에는 설비 특성상 가속도계 및 전치증폭기의 건전성을 확인할 수 없다. 따라서 본 논문에서는 경상운전 중 가속도계와 전치증폭기의 건전성을 확인할 수 있는 기법을 제시하고자 한다.

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슬랙스 실루엣의 도형적 해석을 이용한 패턴 연구 (A Study on Pattern Using Geometric Interpretation of Stacks Silhouette)

  • 강석경;임원자
    • 한국의류학회지
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    • 제21권5호
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    • pp.807-820
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    • 1997
  • This exploratory research was intended to develop and test a slacks pattern based upon conic model. Data came from measurements of photograph of three subjects. Silhouette of slacks was close fit on waist and hip and loose under hip level. This three-dimensional form was modeled with truncated cones. This conic model was truncated by plane of the waist level, the abdomen level, the hip level, the crotch level and the ankle level parallel to the floor. Two models that have differences in back part of the model were tested. Drafted patterns from two models were taken for each subject. Drafted experimental pattern was operated for slacks pattern. The first step was to make sideseam. Parts over crotch level were moved to both sides. And then to make waistdarts. Experimental pattern had two darts each in front and back. Each experimental slacks was evaluated by sensory test to appearance and comfort by five judges. The results can be summarized as follows. 1) Appearance and comfort of experimental pattern were judged to be satisfactory. Especially these patterns were fitted we18 in waist darts front and back. So we evaluated that was proper pattern for slacks. 2) Model 2 was better in appearance than model 1. But Model 1 was more comfortable in non significant difference. This was supposed to be resulted from fit more closely of model 2. 3) considering preceding results, this geometric model based upon truncated cone was applicable for slacks pattern.

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동의보감(東醫寶鑑)에 나타난 습사(濕邪)의 특징 증상에 대한 고찰(考察) (Study for the characteristic symptoms of Dampness in Donguibogam(東醫寶鑑))

  • 정현종
    • 대한한의진단학회지
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    • 제17권2호
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    • pp.90-111
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    • 2013
  • Objectives Migratory pathogenic factor(六淫) occupies an important position in the etiology of Korean Medicine. This paper shows how Dampness, one of Migratory pathogenic factor(六淫), is explained in Donguibogam(東醫寶鑑). And, based on this, we will figure out how to make a judgement of Dampness through diagnosis. Method 1. Collect parts of Dampness mentioned in Donguibogam(東醫寶鑑). 2. From the collection, extract contents about mechanism and symptom of Dampness, which is considered necessary for diagnosis. 3. Put all the extraction together, suggest the diagnosis element which can be criteria of judgement of Dampness through diagnosis. Result & Conclusions The occurrence of Dampness come from a wet climate and environment externally, and overeating of greasy food and digestive disorder internally. There are many different kinds of symptoms throughout the body cause of poor circulation. Dampness is classed as Cold-dampness, Damp-heat, and Dampness-phlegm depending on characteristic symptoms, and mainly shows musculoskeletal disease and digestive troubles. Typical symptoms are pitting edema, distention and fullness, moderate and thready pulse, volume of perspiration increase, loose feces, urine volume decrease, pain of joint and muscle, restriction of movement, etc.

색상정보를 이용한 원자로 육안검사용 수중로봇의 위치 추적 (Position Tracking of Underwater Robot for Nuclear Reactor Inspection using Color Information)

  • 조재완;김창회;서용칠;최영수;김승호
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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    • pp.2259-2262
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    • 2003
  • This paper describes visual tracking procedure of the underwater mobile robot for nuclear reactor vessel inspection, which is required to find the foreign objects such as loose parts. The yellowish underwater robot body tend to present a big contrast to boron solute cold water of nuclear reactor vessel, tinged with indigo by Cerenkov effect. In this paper, we have found and tracked the positions of underwater mobile robot using the two color informations, yellow and indigo. The center coordinates extraction procedures is as follows. The first step is to segment the underwater robot body to cold water with indigo background. From the RGB color components of the entire monitoring image taken with the color CCD camera, we have selected the red color component. In the selected red image, we extracted the positions of the underwater mobile robot using the following process sequences: binarization labelling, and centroid extraction techniques. In the experiment carried out at the Youngkwang unit 5 nuclear reactor vessel, we have tracked the center positions of the underwater robot submerged near the cold leg and the hot leg way, which is fathomed to 10m deep in depth.

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한국산 쓸종개, Plotosus lineatus (Thunberg) 수염의 조직 (Histology of the Barbels of Striped Sea Catfish, Plotosus lineatus (Thunberg))

  • 박인석;설동원;김은미;김영자;이영돈
    • 한국수산과학회지
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    • 제38권3호
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    • pp.158-163
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    • 2005
  • This paper deals with the histology of the barbels of striped sea catfish, Plotosus lineatus (Thunberg). This fish have eight noticeable barbels of two pairs on their maxillary and mandibular. Each barbel is composed of an epidermis, dermis and a central rod of cartilage. The epidermis in the middle part of the maxillary barbel is thicker than those on other parts, and formed of stratified epithelium which contains many cutaneous taste buds and a few small club cells. Number of taste buds increase on the middle and posterior part of each barbel. The dermis consists of loose connective tissue fibers which encloses blood vessels and bundles of nerve fibers. The barbels of this fish can be categorized into stiff and flexible types and are accessory, feeding and sensory structures. Thus we substantiate that they are gustatory receptor organs for this fish.

기계공업 종사자의 작업복 착용 실태조사 연구 (A Research of Worker's Uniform in the Mechanical Industry)

  • 김혜령;서미아
    • 복식문화연구
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    • 제10권6호
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    • pp.718-734
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    • 2002
  • The purpose of this study is to provide basic data f3r improvement in Working Uniform in both scientific and efficient ways. The study were enforced by questionnaire and personal interview. The subject of the survey were the workers of 264 in mechanic industry in Seoul. The results obtained from the researches by methods above are as follows. 1. In general, Working Uniform could be classified types of two. One is loose-fitting one-piece garment covering the body and legs, the other is two-piece garment. The latter is a jacket with either sports collar or soutein collar, fastened with either buttons or a zipper and its sleeve is finished by cuffs and tapes. Regarding to color. inkblue, dark navy, khaky, dark beige are favourable ones. 2. In regard to the necessity of uniform that workers suppose, most of them were aware of it and agreed wearing uniform could play an important part. The reason why are on the basis of safety-first and work efficiency and also to protect a body from harmful or toxic dirt specially in machinery workplace. 3. The purpose of wearing an uniform according to statistics of population make some difference in age, gender. categories of industry, and the scale of factory. 4. In regard to care of uniform, front hem, edge of sleeve in a jacket, and knee, hip part in pants were most vulnerable spots for dirt. The parts damaged easily are edge of sleeve in a jacket and a zipper in pants. On the average, laundry have been done by water and was once a week frequency.

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口瘡에 대한 文獻的 考察 (The bibliographical study on pathogenic factor, pathogenesis, symptoms, treatment method and medicine of The gu-chang.)

  • 홍의석;고우신
    • 한방안이비인후피부과학회지
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    • 제12권1호
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    • pp.356-368
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    • 1999
  • The gu-chang is oriental medical disease name. This study has been carried out to investigate pathogenic factor, pathogenesis, treatment method and medicine of the gu chang by referring to literatures. The results were obtained as follows; 1. Pathogenic factors are pungent taste, stir frying, rich and fatty diet, alchol, disorder of emotion, exogenous pathogen, excessive fatigue and indulgence in sexual activities. 2. Pathogenesis of the gu chang is that the fire heat go up to the mouse. 3. The symptoms are divided into two syndrome. one is sthenia syndrome(實證) - red color and swelling, unendurable pain, strong pulse(脈實), the other is asthenia syndrome(虛症) - pink color, a slight pain, relapse, loose stool, feeble pulse(脈虛). 4. The treatment method is divided into two parts. one is a sthenic syndrome (實證) - clearing strong heat (淸實熱), the other is a asthenic syndrome(虛症) - nourishing yin(滋陰) and clearing deficient heat (淸虛熱), reinforcing the spleen and strengthening middle - JIAO(健脾 補中). 5. The prescription were liang ge san(凉膈散), Ij jhong tang(理中湯) ,xie xim tang(瀉心湯), bu ja li jhong tang, (附子理中湯),liuwei wan(六味元), ba wei wan(八味元), zhuye shigao tang(竹葉石膏湯), si wu tang(四物湯), bu zhong yi gi tang(補中益氣湯) etc.

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