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.

산부식 시간에 따른 유전치 법랑질의 부식 유형에 관한 연구

최수미,최영철,박재홍,최성철 大韓小兒齒科學會 2008 大韓小兒齒科學會誌 Vol.35 No.3

이 연구의 목적은 유전치 법랑질에서 무소주 법랑질 층이 있는 치경부에서의 적절한 산부식 시간을 알아보고자 함이다. 경희대학교 치과대학병원 소아치과에 내원한 환아에게서 발거한 치아 순면에 우식이 없는 건전한 치아 32개를 대상으로 실험 하였다. 발거된 유전치의 치경부 법랑질을 35% 인산으로 실험 1군은 15초,실험 2군은 30초,실험 3군은 45초,실험 4군은 60초간 산부식한 후 부식시간에 따른 법랑질 표면의 양상을 SEM으로 관찰하여 평가하였다. 1. 실험 1군에서는 Type 3가 75% 나타났으며 실험 2군과 3군 모두에서 Type 1이 38%, Type 2가 50%로 나타났다. 2. 실험 2군보다 실험 3군에서 산부식된 양상이 좀더 뚜렷하게 나타났다. 3. 실험 4군에서 Type 1이 25%. Type 2가 75%를 보였고 Type 3는 나타나지 않았다. 4. 실험 4군에서는 다른 실험군에서 보다 좀더 전형적인 산부식 양상을 보였다. 5. 설험군 간의 산부식 시간에 따른 부식 양상의 차이는 통계학적으로 유의한 차이를 보였다(p<0.05). 6. 산부식 시간이 길수록 부착에 유리한 Type 1과 Type 2가 주로 관찰되었으며 Type 3는 드물게 관찰되었다(p<0.05). 유전치에서 무소주 법랑질 층이 주로 존재하는 치경부 측에,와동의 변연부가 형성될 때에는 산부식 시간을 다소 길게 45∼60초 정도 하는 것이 수복물 유지를 향상시킬 것으로 여겨진다. The presence of a"prismless" layer on the enamel surface particularly on deciduous teeth has been reported by a number of workers. This structure, which appears to lack the normal prism delineations, could interfere with tag formation and hence, reduce bonding to such surfaces. The purpose of this study was to investigate the relationship of etching times on the effect of acid etching on primary enamel with respect to the quality of etching patterns. Labial surfaces of 32 extracted or exfoliated caries-free primary anterior teeth were used. 35% phosphoric acid gel was used only cervical regions of labial surfaces for each etching time group, 15, 30, 45 and 60 seconds. The surfaces were then washed with water for 20 seconds and dried with air spray for 20 seconds. 1. The Type 3 is 75% when the 15 seconds acid etching time was used. 2. The Type 1 is 38% and Type 2 is 75% when the 30 and 45 seconds acid etching time was used. 3. The Type 1 is 25% and Type 2 is 75% when the 60 seconds acid etching time was used. 4. An etching time of 60 seconds produced a constant and regular etching pattern. 5. There is a significant difference between the groups with respect to the patterns of etch achieved(p<0.05). 6. We confirmed that the acid induced patterns(type 1, 2) became more pronounced when the application time increased(p<0.05). 45∼60 seconds was the optimal time for etching on the primary enamel.

복합레진 적층계면에서 oxygen inhibition의 영향에 관한 연구

최수미,박재홍,최성철,김광철,최영철 大韓小兒齒科學會 2010 大韓小兒齒科學會誌 Vol.37 No.3

The purpose of this study was to assess the effect on oxygen inhibition layer(OIL) for the interfacial bonding between resin composite layers, including shear bond strength, fracture modes and degree of conversion. The first layer of specimen was filled with Z-250(shade A3) and was cured for 40s. The second layer of specimen was filled with same composite(shade A1) and was cured for 40s. The first layer of specimens for each group were prepared by methods as followings. Control(curing in atmospheric air), Group1(curing against Mylar strip), Group2(scrubbed with a acetonesoaked cotton), Group3(using Tescera light cup), Group4(using Tescera heat cup), Group5(stored in disti1led water for 30days at 37℃), Group6 (using bonding agent). The results were as follows: 1. There was no statistically significant different shear bond strength between control and group 1(p>0.05). 2. Group 2 showed significantly lower shear bond strength than control and group 1(p<0.05). 3. The observation of the fracture surface leads to the evidence that a major difference occurs in the case of control, group1 and group 3 samples which break mainly cohesively while the other groups break in majority adhesively. 4. The results of FTIR showed that the degree of conversion was the highest in group 2 and the lowest in control group(p<0.05). It can be concluded that an OIL is not necessary for bonding with composite resin. But if a reduced critical amount of the unreacted monomer is present, it was detrimental to bonding additional layers of composite. Further study, such as the quantitative analysis of the unreacted monomer are required. 복합레진의 적층계면에서 산소억제층(oxygen inhibition layer:이하 OIL)의 영향을 연구하기 위해, 아크릴릭 몰드(하층)에 복합레진의 shade A3를 충전한 후 표면의 조건을 달리하여 중합하였으며 상층은 shade A1으로 충전하고 중합하였다. 대조군(OIL 존재), 1군(OIL 형성억제), 2군(OIL 형성억제+레진표면의 미반응 모노머 제거), 3군(가압하에 중합), 4군(열중합), 5군(시효처리), 6군(시효처리+본딩제 도포)로 하층의 계면조건을 다르게 하였다. 전단결합강도와 파절양상, 전환률을 분석하여 다음의 결과를 얻었다. 1. 전단결합강도 측정 결과 대조군과 제 1군 사이에 통계학적으로 유의한 차이가 없었다(p>0.05). 2. 제 2군은 대조군과 1군에 비해 낮은 결합강도를 보였다(p<0.05). 3. 제 3군은 가장 높은 결합강도를 보인 반면, 4군은 가장 낮은 결합강도를 보였다. 4. 6군은 5군보다 두 배 정도 높은 결합강도를 보였다. 5. 대조군과 1군 및 3군에서는 주로 응집성 복합레진파절이 일어난 반면 2군, 4군, 5군과 6군에서는 주로 접착성 계면파절이 일어났다. 6. FTIR로 전환률을 측정한 결과 2군에서는 50.55%로 가장 높았고, 대조군에서는 가장 낮았다(p<0.05). 전단결합강도와 전환률의 결과로 보아, OIL은 복합레진 계면의 결합에 필수적인 요인은 아니며, 표층의 미반응 모노머가 결합강도에 영향을 미치는 것으로 보인다. 향후 계면 결합강도에 영향을 미칠 수 있는 미반응 모노머의 정량적인 분석을 통한 추가적인 연구가 필요할 것으로 생각된다.

단일 처리기간에 의한 들깨의 생육 및 개화조절

최영환,최영훈,강점순,손병구,김용철,최인수,주우홍 밀양대학교 농업기술개발연구소 2000 農業技術開發硏究所報 Vol.4 No.1

It's not uncommon for the amount of leaves to be reduced significantly due to the early differentiation of flower-bud by short-day condition when growing perilla for harvesting the leaves in the greenhouse during the winter. This study analyzed the effect of day-length on the growth and regulation of flowering, which are closely related with differentiation of flower and amount of leaves. Development of new leaf was inhibited by short-day treatment for more than 5 days. As the period of short-day was longer, the effect on the development of new leaf inhibition was more evident. Number of leaves was reduced in both 40 days and 110 days short-day treatments as period of short-day length was longer. Short-day treatment for less than 3 days did not induce flowering, but short-day treatment for more than 5 days induced flowering. As the period of short-day treatment was shorter, percentage of flowering was lower and days to flowering was longer. That is, when treated for 20 days, flowering began in 20 days. Seed weight was reduced as the length of short-day treatment was longer.

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.

Floristic characteristics of vascular plants and first distributional report of Pseudostellaria baekdusanensis M. Kim in Yongneup wetland protected area

Young-Chul Kim,Hyun-Hee Chae,Sang-Heock Oh,Seung-Ho Choi2,Moon-Pyo Hong3,Gi-Heum Nam,Jae-Yoon Choi,Hyun-Sook Choi,Kyu-Song Lee 한국환경생태학회 2015 한국환경생태학회지 Vol.29 No.2

Yongneup wetland protected area, the only high moor in Korea, is a core area to conserve biodiversity. Even though the Yongneup wetland protected area is relatively small, various plant species are distributed in the Yongneup wetland protected area because it includes various habitats showing different environmental gradients. Vascular plants distributed in the Yongneup wetland protected area were identified as a total of 376 taxa that is composed of 73 families, 217 genera, 322 species, 3 subspecies, 44 varieties and 7 forms. For endangered plants designated by the Ministry of Environment, 5 species including Trientalis europaea var. arctica, Lilium dauricum, Halenia corniculata, Lychnis wilfordii and Menyanthes trifoliata were found and 34 taxa were confirmed to be distributed only in the mountainous wetland habitats. Regarding naturalized plants, a total of 11 taxa were distributed, but most of them were distributed in the areas where artificial interference has occurred. And in areas inside the wetlands that are relatively well preserved, 2 species of Bidens frondosa and Erigeron annuus were observed. In this study, the occurrence and distribution of Pseudostellaria baekdusanensis M. Kim, which was recently found in Mt. Baekdu and reported as a new species, were identified in the Yongneup wetland protected area. A wetland is a very vulnerable area to drastic environmental changes and damages to its ecosystem could cause the extinction of rare plant species which are distributed only in the wetlands. Therefore, it is mandatory that current status of the Yongneup wetland protected area is evaluated and actions to prevent rapid environmental changes are taken. Fourteen separate investigations were conducted in 2013 and another four in 2014, to evaluate current status of the Yongneup wetland protected area. These investigations have provided us the basic information for future actions of conservation and restoration.

재발성 류마티즘 환자에서 발작의 유발인자

주유철,이동민,양종태,신병철,임태영,서정균,정기영,최동헌,김원,조영신,고희관 조선대학교 2001 The Medical Journal of Chosun University Vol.26 No.2

Background and Objectives : Palindromic rheumatism (PR) is known to be triggered without any obviously inciting events in most patients, although, in a few cases, attacks have been noted to relate to another events such as weather change, childbirth, ingestion of certain foods, or over-exercise. The aim of this study was to characterize the triggering factors on palindromic attacks. Materials and Methods : We evaluated sixty-four patients with PR for the presence of triggering factors and the relationship between attacks and triggering factors by interview of patients. We considered that there was an probable association between episodes and PR, if episodes within 24 hours prior to PR had triggered at least 50% of all attacks and a definite association between episodes and PR, if episodes within 24 hours prior to PR had triggered 100% of all attacks. Results : In 15 patients (35.9%), there was a possible association between episodes of PR and initiating events. In 8 patients (12.5%), there was a definite association between episodes of PR and initiating events. The triggering factors were physical over-activity including exercise (19/64: 29.7%), foods, such as rawfish, crab, and chicken, including alcohol (19/96: 19.8%). However, there were no difference between the groups with and without the triggering factor in sex ratio, duration and onset of PR, the positive rate of rheumatoid factor and involved sites. Conclusion : Our observations showed that PR was triggered by physical over-activity more than in previous reports and hypersensitivity to foods was a causative factor in some patients with PR. However, patients with triggering factors had a similiar clinical profile to patients without triggering factors.

IDIS그룹의 창조와 혁신 성장 메커니즘-사람, 기술, 그리고 M&A가 만들어 가는 글로벌 넘버원

최정철(Jeong-Chul Choi),박기찬(Kichan Park),김영달(Young-dal Kim),박재홍(Jae-hong Park) 한국경영학회 2021 Korea Business Review Vol.25 No.신년 특별호

본 사례연구는 보안장비분야 세계 정상에 오른 창업가의 끊임없는 창조와 혁신의 경영철학과 사업성장의 역정을 살펴보는 데 목적이 있다. 그룹의 모태가 되는 IDIS는 김영달 대표이사가 KAIST 전산학과 박사과정 중 창업하여 세계 최초로 DVR(Digital Video Recorder)제품을 개발하는 등 보안 분야 디지털 기술을 선도하고 있다. 특히 미국항공우주국(NASA) 등 하이엔드 시장에 진출하는 과정에서 기술력을 인정받아 2000년 시드니 올림픽 주경기장과 오페라하우스 전역에 최첨단 보안장비를 설치함으로써 전 세계에 IDIS의 기술력을 알렸다. 그리고 디지털 전환(Digital Transformation) 시대로 패러다임이 급속히 변화하는 환경에서 보안 분야를 주도함으로써 마침내 세계 정상에 올랐다. 무엇보다 보안 분야 세계 정상에 오른 기업의 최고경영자로서 김영달 대표가 새롭게 도전하고 있는 그의 ‘철학이 있는 경영’, 바로 혁신을 꿈꾸는 엔지니어에서 ‘사회적 부’를 창출해 가는데 기여하는 기업가가 되려는 노력은 IDIS그룹의 경영성과에 의해 증명되었다. 성과분석에 있어서도 “기업의 규모가 성장하면 사회적 책임과 역할도 확대되어야 하므로 좋은 일자리를 만들고 구성원의 행복과 지역사회의 발전을 지속적으로 견인해야 한다”는 그의 ‘안정기반 성장전략’에 초점을 두었다. 정상에 오른 기업으로서 IDIS그룹이 보여준 성장전략과 경영성과는 다음의 세 가지로 요약된다. 첫째, 문어발식으로 규모를 확대하는 것이 아니라 일자리 창출과 고용안정 등 사회적 부를 창출하기 위한 전략으로 관련 다각화 M&A를 신중하게 진행했다. 둘째, 창업을 결심했을 때처럼 ‘국내 기술로 글로벌 넘버원이 될 수 있는 기업’을 찾아 M&A를 추진한 결과, 산업용 디스플레이를 개발하는 ㈜코텍, 프린터 관련 기업 ㈜빅솔론과 IDIS의 사내벤처로 창업한 아이디피(주)를 결합하여 사업의 포트폴리오를 성공적으로 구축했다. 셋째, ㈜코텍, ㈜빅솔론의 창업주들이 직접 김영달 대표를 찾아와 인수합병을 제안했고 M&A 이후 R&D 기술력 기반으로 성장시켜가고 있다. 본 사례연구를 위해 다섯 번의 인터뷰와 20시간이 넘는 질문과 토의 중에서도 밝은 미소와 사업에 대한 열정을 잠시도 잃지 않는 그의 인간적 매력 또한 이를 증명해 주었다. The purpose of this case study is to examine the mechanism of successful business growth of an entrepreneur with his philosophy in creativity and innovation. IDIS was founded by CEO Young-dal Kim and its founding members while attending the Ph.D. in Computer Science at KAIST Graduate School. They developed the worlds first DVR product, and are currently leading digital technology in the field of security. In particular, in the process of advancing to high-end markets such as NASA, technological prowess was recognized, and state-of-the-art security equipment was installed throughout the Opera House from the main stadium of the ‘2000 Sydney Olympics’. Since then, the world has begun to be interested in IDIS technology. IDIS finally reached the top of the world by leading the security field in an environment in which the paradigm to the era of digital transformation is rapidly changing. The core of this case is to look at his “management with philosophy” that CEO Kim is taking on a new challenge as the CEO of a company that has reached the top of the world. He now wants to become an entrepreneur who contributes to creating ‘social wealth’ from an engineer who dreamed of innovation. In other words, his philosophy is that social responsibilities and roles should be expanded as the size of a company grows, and companies should continuously create quality jobs and lead the happiness of members and the development of local communities. The strategy and achievements of IDIS Holdings as a top-rated company are summarized in the followings. First, CEO Kim transformed IDIS into a holding company as a strategy to continuously create social wealth, such as job creation and security, rather than just expanding the scale. Second, as a result of finding “a company that can become the global number one with domestic technology,” KORTEK, BIXOLON, and IDP have successfully formed a business portfolio. Third, unusually, the founders personally visited CEO Kim and proposed M&A, and actually all growing successfully after M&As.

정신분열병 환자들의 自己灣入에 관한 예비 연구

박성봉,김영미,전성일,이기철,김영훈,정영조,이영렬,이정호,최영민 大韓神經精神醫學會 1997 신경정신의학 Vol.36 No.6

목 적 : 정 신분열병 환자의 자기만입 정도에 영향을 미치는 인구학적 변인들 및 질병연관 변인들을 규명해 보고자 하였다. 또한. 환자들의 자기만입과 병식 사이의 연관성. 자기만입과 자존심 사이의 연관성을 알아보고자 하였다. 방 법 : 정신과 의사가 병록지와 면담을 통하여 대상 정신분열병 환자들의 인구학적 변인들 및 질병연관 변인들에 관한 자료를 얻고 환자들의 병식 정도를 평가한 후, 환자들로 하여금 자기보고형의 자기만입 척도와 자존심 척도를 시행하게 하였다. 총 111명의 환자가 연구대상으로 선택되었다. 결과: . 1) 여자가 남자보다 유의하게 높은 자기만입 척도 점수를 나타내었다 2) 질병연관 변인들 중 하위집단 사이에 자기만입 척도 점수의 유의한 차이를 보이는 변은 없었다. 3) 자기만입 척도 점수와 병식 점수 사이에 유의한 상관관계가 없었다. 4) 자기만입 척도 점수와 자존심 척도 점수 사이에 유의한 역상관 관계를 보였다. 결 론 : 본 예비 연구의 결과로 보아 정신분열 병 환자의 병식이 부족한 상태에서도 자기만입이 진행될 수 있으며. 자기만입이 심할수록 환자의 자존심이 저하되는 것으로 생각된다. 또한 여자 환자들이 남자 환자들보다 자기만입에 더 취약한 것으로 생각된다. 따라서 정신분열 병 환자의 이해와 치료를 위하여 자기만입에 관한 지속적인 연구가 필요할 것으로 생각된다. objective : This study was conducted to identify demographic variables and illness related variables which may affect the severity of self-engulfment in the patients with schizophrenia. We also studied the relationship between self-engulfment and insight, and the relationship between self-engulfment and self-esteem. Methods : Data on demographic variables and illness related variables for the subjects were gathered from hospital records and clinical interviews by the psychiatrists. Degree of insight for the subjects was assessed through clinical interviews by the psychiatrists. Degree of self-engulfment and self-esteem for the subjects was assessed from the self-engulfment scale and the self-esteem scale respectively. A total of 111 patients with schizophrenia were selected for statistical analysis. Results 1) The females exhibited significantly higher scores than the males on the self-engulfment scale. 2) There was no illness related variable, which exhibited a significant difference among subgroups on the self-engulfment scale. 3) There was no significant correlation between the self-engulfment scores and the insight 4) There was a significantly inverse correlation between the self-engulfment scores and the self-esteem scores. Conclusion : The results of this preliminary study suggest that self-engulfment may develop despite lack of insight and that there was inverse relationship between self-engulfment and self-esteem in the patients with schizophrenia. It also suggests that females are more subject to self-engulfment than males. So, authors suggest that it is valuable to do further studies of self-engulfment in the patients with schizophrenia.

Direct effectiveness of pneumococcal polysaccharide vaccine against invasive pneumococcal disease and non-bacteremic pneumococcal pneumonia in elderly population in the era of pneumococcal conjugate vaccine: A case-control study

Kim, Jong Hun,Chun, Byung Chul,Song, Joon Young,Kim, Hyo Youl,Bae, In-Gyu,Kim, Dong-Min,Choi, Young Hwa,Jun, Yoon Hee,Choi, Won Suk,Kang, Seong Hee,Kwon, Hyun Hee,Jeong, Hye Won,Kee, Sae Yoon,Hur, Jia Elsevier Ltd. 2019 Vaccine Vol. No.

<P><B>Abstract</B></P> <P><B>Background</B></P> <P>While herd effects and serotype replacement by childhood pneumococcal protein conjugated vaccines (PCVs) continues to accumulate worldwide, direct effectiveness of 23-valent pneumococcal polysaccharide vaccine (PPV23) against pneumococcal diseases in the elderly has been challenged. We estimated the direct effectiveness of PPV23 in the elderly population.</P> <P><B>Methods</B></P> <P>For a hospital-based case-control study, cases of invasive pneumococcal disease (IPD) and non-bacteremic pneumococcal pneumonia (NBPP) (adults ≥ 65 years) were identified in 14 hospitals participated in the pneumococcal surveillance program from March 2013 to October 2015, following implementation of PPV23 national immunization program (NIP) for the elderly in the Republic of Korea. Controls matched by age, sex, and hospital were selected at ratios of 1:2 (IPD) or 1:1 (NBPP). Clinical data and vaccination records were collected. Vaccine effectiveness was calculated as (1-adjusted odds ratio) × 100.</P> <P><B>Results</B></P> <P>We enrolled 148 IPD and 557 NBPP cases, and 295 IPD and 557 NBPP controls for analyses. Overall effectiveness of PPV23 against IPD was 28.5% [95% confidence interval (CI) −5.8%–51.6%] and against NBPP was 10.2% (-15.1-30.6) in all patients ≥ 65 years. However, in subgroup analysis of patients aged 65–74 years, PPV23 was protective against IPD [effectiveness 57.4% (19.4–77.5)] and against NBPP [effectiveness 35.0% (2.3–56.7)]. Furthermore, serotype-specific effectiveness of PPV23 against IPD was 90.6% (27.6–98.8) for PPV23-unique serotypes and 81.3% (38.6–94.3) for PPV23 serotypes excluding serotype 3.</P> <P><B>Conclusions</B></P> <P>This study indicates that PPV23 with broad serotype coverage might be beneficial in preventing IPD and NBPP due to non-PCV13 serotypes in the young-elderly, with potentially increasing effectiveness in the setting of childhood PCV NIP.</P> <P><B>Highlights</B></P> <P> <UL> <LI> National immunization program for PPV23 for the elderly was implemented in Korea. </LI> <LI> PPV23 was effective against IPD and NBPP for young elderly patients aged 65–74. </LI> <LI> Effectiveness of PPV23 against IPD was higher for PPV23 unique serotypes. </LI> <LI> PPV23 was non-protective against IPD caused by PCV13 serotypes. </LI> </UL> </P>