AN IN-SITU YOUNG’S MODULUS MEASUREMENT TECHNIQUE FOR NUCLEAR POWER PLANTS USING TIME-FREQUENCY ANALYSIS

YOUNG-CHUL CHOI,DOO-BYUNG YOON,JIN-HO PARK,권휴상 한국원자력학회 2009 Nuclear Engineering and Technology Vol.41 No.3

Elastic wave is one of the most useful tools for non-destructive tests in nuclear power plants. Since the elastic properties are indispensable for analyzing the behaviors of elastic waves, they should be predetermined within an acceptable accuracy. Nuclear power plants are exposed to harsh environmental conditions and hence the structures are degraded. It means that the Young’s modulus becomes unreliable and in-situ measurement of Young’s modulus is required from an engineering point of view. Young’s modulus is estimated from the group velocity of propagating waves. Because the flexural wave of a plate is inherently dispersive, the group velocity is not clearly evaluated in temporal signal analysis. In order to overcome such ambiguity in estimation of group velocity, Wigner-Ville distribution as the time-frequency analysis technique was proposed and utilized. To verify the proposed method, experiments for steel and acryl plates were performed with accelerometers. The results show good estimation of the Young’s modulus of two plates.

유아의 자연물에 대한 연상, 유사성, 생명 개념에 관한 연구

최진승,김지영 동아대학교 교육대학원 1998 동아교육논총 Vol.24 No.-

본 연구는 유아가 자연물에 대한 지식을 연상하고 생명 유무와 유사성을 판단하는 기준을 공통적인 준거로써 찾고 그 준거별 반응정도가 연령 및 성별, 자연물의 범주에 따라서 어떠한 양상을 보이면서 발달하는지 밝히는데 그 목적을 두었다. 본 연구의 대상은 부산 시내 유치원에 재원하는 3, 4, 5세 유아 90명이며 유아에게 제시된 자연물은 예비 조사와 친숙도 검사를 통해 선정하였으며, 범주에 따라서 동물, 식물, 천체, 기타 무생물 범주로 나뉘며 각 범주별로 3개씩 총 12개이다. 자료는 인터뷰식으로 진행하여 수집되었으며 유아의 반응은 모두 녹음하여 준거에 따라 수량화하였고, 통계처리는 일원변량분석, 다변량분석, t-검증, Duncan(.05)사후 검증 등을 활용하였다. 본 연구의 결과 및 논의를 통해 얻어진 결론은 다음과 같다. 첫째, 자연물의 소유, 형태, 주제에 관한 개념은 3세에 이미 발달되어 있으며, 색깔과 기능에 관한 개념은 4세와 5세 사이에 크게 발달하는 것으로 보인다. 둘째, 여아는 남아보다 자연물의 기능 및 행위에 관한 개념을 더 먼저 획득한다. 셋째, 동물 및 기타 무생물 범주에 관한 자연물의 개념은 식물 범주 및 천체 범주에 대한 개념보다 더 먼저 발달한다. 넷째, 유아의 자연물의 유사성 판단은 주제-지각-기능-개념 이행으로 변화하며 발달한다. 여섯째, 유아들이 자연물과 유사한 대상으 판단할 때 근거하는 기준은 자연물의 범주에 따라 다른데, 생물 범주는 기능적인 법칙에 근거하고 무생물 범주는 지각적인 특징에 근거하여 판단한다. 일곱째, 자연 법칙에 근거하여 자연물의 생명성을 판단할 수 있는 능력은 5세에 갖추어어지며, 자연물의 범주에 따라 생명성의 판단의 기준이 다르다. 동물 범주는 자연법칙에 근거하며 식물 범주는 사람들의 활동과 개입 유무에 근거하고, 무생물 범주는 의인적인 준거에 근거하여 판단하는 경향이 높다. The purpose of this study is that how the young childrens' association, simialrity, life concept on natural kinds changes with age, sex, and the categories of natural kinds. The subjects in this study were 90 young children who were 3, 4, and 5 years old, and sampled from 3 kindergartens in Pusna. Natural kinds were selected through the pilot test and the categories of natural kinds were divided into animal, plant, planet, and dnonbiological category. Following conclusions were derived from discussion on the results to this study: 1.Young children's association about natural kinds' having, shape, thematic knowledge don't change with age, and their association for the color, functional knowledge of natual kinds were increaed with age. 2.Female childrens' association is higer than male in the natural kinds' functional knowledge. 3.Young childrengs association about plant, planet is increasing with age. Therefore, young childrens' concept about animal, nonbiological kinds is formed nearly at 3 age olds, and young childrens' concept about plant, planet develops highly between the age of 4 and 5 years old. 4.Young children's association about natural kinds' shape is high in the all categories of natural kinds, their assocaition about natural kinds' thematic knowledge is high in nonbiological category. In addition, their association about natural kinds' function is high in animal category at most. 5.Young childrens' reponses about natural kinds' thematic simiarity are decreasing with age. On the other hand, their responses about natural kinds' perceptual, functional simiarity are increasing with age. The result suggests that young childrens' concept on natural kinds is developing thematic-perceptural-founctional-conceptual shift. 6.Young childrens' assocaition about the simiarity is based on objects' founctional character in biological category. On the other hand, their assocaition about inanimates' similarity is based on the perceptual character in nonbiological category. 7.Young childrens' ability to discriminate the animates-nonanimates is increasing at 5 years old. Therefore, young childrens' life concept is formed nearly at 5 years old. 8.Young childrens discriminate between animate and inanimate things in animal category at the based of animals' functional character and in plant category at the based of persons' activity. However they justify the objects' lives at the based of perceptual character in nonbiological category.

AN IN-SITU YOUNG'S MODULUS MEASUREMENT TECHNIQUE FOR NUCLEAR POWER PLANTS USING TIME-FREQUENCY ANALYSIS

Choi, Young-Chul,Yoon, Doo-Byung,Park, Jin-Ho,Kwon, Hyun-Sang Korean Nuclear Society 2009 Nuclear Engineering and Technology Vol.41 No.3

Elastic wave is one of the most useful tools for non-destructive tests in nuclear power plants. Since the elastic properties are indispensable for analyzing the behaviors of elastic waves, they should be predetermined within an acceptable accuracy. Nuclear power plants are exposed to harsh environmental conditions and hence the structures are degraded. It means that the Young's modulus becomes unreliable and in-situ measurement of Young's modulus is required from an engineering point of view. Young's modulus is estimated from the group velocity of propagating waves. Because the flexural wave of a plate is inherently dispersive, the group velocity is not clearly evaluated in temporal signal analysis. In order to overcome such ambiguity in estimation of group velocity, Wigner-Ville distribution as the time-frequency analysis technique was proposed and utilized. To verify the proposed method, experiments for steel and acryl plates were performed with accelerometers. The results show good estimation of the Young's modulus of two plates.

Localization of Antigenic Sites at the Amino-terminus of Rinderpest Virus N Protein Using Deleted N Mutants and Monoclonal Antibody

Kang-seuk Choi,Jin-ju Nah,Young-joon Ko,Shien-young Kang,Yi-seol Joo 대한수의학회 2003 Journal of Veterinary Science Vol.4 No.2

of Antigenic Sites at the Amino-terminus of Rinderpest Virus N Protein Using Deleted N Mutants and Monoclonal AntibodyKang-seuk Choi*, Jin-ju Nah, Young-joon Ko, Shien-young Kang1 and Yi-seok JooNational Veterinary Research and Quarantine service, Ministry of Agriculture and Forestry, 480 Anyang, Gyounggi 430-824, Korea1Research Institute of Veterinary Medicine, College of Veterinary Medicine, Chungbuk National University, 48 Gaeshin-dong, Heungduk-gu, Cheongju, Chungbuk 361-763, KoreaReceived April 2, 2003 / Accept July 10, 2003J. Vet. Sci. (2003), 4(2), 167-173JOURNAL OFVeterinaryScience*Corresponding author: Kang-seuk Choi National Veterinary Research and Quarantine service, Ministry of Agriculture and Forestry, 480 Anyang, Gyounggi 430-824, Korea Tel: +82-31-467-1860, Fax: +82-31-449-5882 E-mail: choiks@nvrqs.go.kr

가속도계를 이용한 재료의 영계수 측정방법

손창호(Sohn, Chang-Ho),박진호(Park, Jin-Ho),윤두병(Yoon, Doo-Byung),정의필(Chong, Ui-Pil),최영철(Choi, Young-Chul) 한국소음진동공학회 2006 한국소음진동공학회 논문집 Vol.16 No.11

For the description of the elastic properties of linear objects a convenient parameter is the ratio of the stress to the strain, a parameter called the Young's modulus of the material. Young's modulus can be used to predict the elongation or compression of an object as long as the stress is less than the yield strength of the material. Conventional method for estimating Young's modulus measured the ratio of stress to corresponding strain below the proportional limit of a material using a tensile testing machine. But the method needs precision specimens and expensive equipment. In this paper, we proposed method for estimating Young's modulus using accelerometer. The basic idea comes from that the wave velocity is different as the Young's modulus. To obtain Young's modulus, a group velocity is obtained. It is difficult to measure group velocity. This is because plate medium has a dispersive characteristics which has different wave speed as frequency. In this paper, we used Wigner-Ville distribution to measure group velocity. To verify the proposed method, steel and acryl plate experiments have been performed. Experimental results show that the proposed method is powerful for estimating Young's modulus.

Factors associated with the risk of colorectal neoplasia in young adults under age 40

Ilsoo Kim,Han Hee Lee,Young Jae Ko,Ho Eun Chang,Dae Young Cheung,Bo-In Lee,Young-Seok Cho,Jin Il Kim,Myung-Gyu Choi 대한내과학회 2022 The Korean Journal of Internal Medicine Vol.37 No.5

Background/Aims: Recent epidemiologic studies have shown a continued increase in colorectal cancer incidence among younger adults. Little is known about the factors that contribute to the development of young-onset colorectal neoplasia (CRN). Methods: A cross-sectional analysis was performed for individuals younger than 40 years who underwent colonoscopy in Seoul St. Mary’s Hospital and its affiliated health screening center. High-risk CRN was defined as adenoma or sessile serrated lesion ≥ 10 mm, with three or more adenomas, villous histology, high grade dysplasia, or carcinoma. Results: Of these 13,621 included participants, 2,023 (14.9%) had one and more CRN. Young patients with CRN tended to be elderly, male, obese, smoker, having a habit of drinking, and having comorbidities such as hypertension, dyslipidemia, diabetes, and chronic kidney disease. In a multivariate analysis adjusted for age, sex, obesity, smoking status, and alcohol intake, old age (odds ratio [OR], 1.086; 95% confidence interval [CI], 1.054 to 1.119), male sex (OR, 1.748; 95% CI, 1.247 to 2.451), obesity (OR, 1.439; 95% CI, 1.133 to 1.828), and smoking (OR, 1.654; 95% CI, 1.287 to 2.127) were independent risk factors for overall CRN. Obesity and smoking as two modifiable factors increased the risk for high-risk CRN even more than for overall CRN (OR, 1.734; 95% CI, 1.168 to 2.575 and OR, 1.797; 95% CI, 1.172 to 2.753, respectively). Conclusions: Obesity and smoking were modifiable risk factors for CRN in young adults. They increased the risk for highrisk CRN even more than for overall CRN. A colonoscopy might be beneficial for young individuals with these factors.

중추에서 Prostaglandin계가 Renin-angiotensin System에 미치는 영향

최영태,김종승,문성호,오형균,김재훈,전제열,염철호,윤평진 朝鮮大學校 附設 醫學硏究所 1997 The Medical Journal of Chosun University Vol.22 No.1

Role of prostaglandins on the renin-angiotensin system in the central nervous system was examined in normotensive and 2-kidney, 1 clip (2K1C) hypertensive rats. The experiment was done under thiopental (50 ㎎/㎏, IP) anesthesia. Captopril and indomethacin were injected into the right lateral cerebral ventricle. Arterial blood pressure and heart rate were recorded from the femoral artery. Intracerebroventricular (ICV) captopril (1 ㎎) caused a decrease in mean arterial pressure in both normotensive and 2K1C hypertensive rats. The depressor response to captopril was more sensitive in hyper-tensive rats than in normotensive rats. Indomethacin treatment (ICV, 200 ㎎) altered the depressor response to captopril neither in normotensive nor in hypertensive rats. These results suggest that the cardiovascular effect of renin-angiotensin system in the central nervous system may not be mediated via prostaglandin systems in normotensive and 2KlC hypertensive rats.

Goretex를 이용한 융비술

최진영,민철기,명훈,황순정,서병무,이종호,정필순,김명진 大韓顎顔面成形再建外科學會 2003 Maxillofacial Plastic Reconstructive Surgery Vol.25 No.4

융비술시 실리콘 고무는 다루기 쉽고 조직 반응이 적어 현대 많이 돌출의 합병증이 생길 수 있다. 저자등은 이러한 실리콘의 단점을 보완할 수 있는 goretex를 사용하여 융비술을 시행하고 비첨에 대해서 자가연골을 이식하여 만족할 만한 결과를 얻었기에 goretex가 안면부 연조직의 증강을 위한 이식재료로 적합하다고 생각되어 문헌고찰과 함께 보고하는 바이다. Many different materials have been used to provide augmentation of the nasal dorsum. this include both autogenous and homogenous materials,as well as allografts. Silicone among the artificial materials has been most widely used. The silicone has some advantages and disadvantages. Goretex(expanded polytetra-fluoroethylene) which has widely used in vascular surgery and abdominal surgery can be used for facial soft tissue augmentation. The author presemts 2 cases of nasal augmentaion using goretex with literature review.

신경망 시각인식을 위한 양안영상 전처리 시스템 구현

최진우,김영택 慶星大學校 1998 論文集 Vol.19 No.2

To design a computer vision system, the theory for humans visual perception in biological brain and cognitive science is referred in respect that those mechanism can be a good model for a machine vision system. Human's hierarchical, parallel and distributed processing on a stereo vision structure is studied to simulate visual perception. The way of integrating a stereo visual information processing model of V₁, V₂with the neural network theory is a major concern of this paper. Especially, experiments on a stereo image processing model for complex cell of V₂has been implemented.

표현주의 논쟁과 브레히트

최영진 한국브레히트학회 1998 브레히트와 현대연극 Vol.6 No.-

Die Expressionismusdebatte bezeichnet die in der Moskauer Exilzeitschrift Das Wort (1937/38) ausgetragene Diskussion zwischen den antifaschistischen Schriftstellern, Wissenschaftlern und Kunstlern. Die Debatte wurde von den Beitragen Klaus Manns und Alfred Kurellas uber den Expressionisten Benn ausgelost, dehnte sich aber zu einer Methodendiskussion im kunstlerischen Schaffen aus. Bekanntlich findet diese Debatte vor dem Hintergrund der sowjetischen Literaturdebatte, aus der die Doktrin des "sozialistischen Realismus" entwickelt worden ist, statt. In der deutschen Debatte wird jedoch der Expressionismus als Sammelbegriff fur die sogenannten modernen Richtungen mehrheitlich - am leidenschaftlichsten von Bloch - verteidigt. Bloch polemisiert gegen Lukacs, der den Expressionismus auf die "USP-Ideologie" reduziert. Darauf antwortet Lukacs mit seinem Beitrag Es geht um den Realismus. Die Differenzen zwischen den Kontrahenten Lukacs und Bloch sind erkenntnistheoretisch zu begrunden. Die Expressionismusdebatte ist weitgehend als Realismusdebatte unter der Bezeichnung "Brecht-Lukacs-Debatte" eingeschatzt worden. Brecht hat allerdings weder an der Debatte teilgenommen, noch mit Lukacs debattiert, obwohl er privat gegen Lukacs vehement polemisiert hat. Die Forschung hat das von Brecht vermittelte Lukacs-Bild mehr oder minder vorbehaltlos ubernommen und Lukacs in die Rolle eines "Popanzes" geruckt. Brechts zahlreiche Schriften uber die Expressionismusdebatte sind erst postum veroffentlicht. Das neue Material des Herzfelde-Nachlasses (Briefwechsel zwischen Brecht und Herzfelde) besagt, daβ Brecht eine Buchpublikation vorgesehen hatte, die dessen Stellungnahme zur Debatte enthalten sollte. Daher ist es schwierig zu behaupten, daβ sich Brecht aus solidarischen Grunden bzw. aus Feigheit zuruckgehalten habe, oder, daβ seine Aufsatze von der Moskauer Redaktion des Wortes unterdruckt worden seien. Brecht, der von Bloch als Kronzeugen fur dessen asthetische Theorie gerufen worden ist, sympathisiert mit den Expressionisten, versteht sich aber als Realist. Er stimmt mit Lukacs nur darin uberein, daβ die antifaschistische Literatur eine realistische sein soll. Wahrend Lukacs den philosophischen Traditionen von Hegel, Marx und Lenin verpflichtet ist, knupft Brecht an die naturwissenschaftliche Erkenntnisweise an. Brecht liefert allerdings keine konsequente, abgeschlossene Theorie des Realismus. Bemerkenswert ist, daβ Brecht realistisches Schreiben nicht nur fur den Roman, mit dem Lukacs fast ausschlieβlich argumentiert, sondern auch fur die Lyrik reklamiert.