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.

A simple approach to estimate the mechanical properties of collagen-like microfibrils surrounded by water

Young-june Yoon,Cheol-soo Bae,Ho-sik Park 한국멀티미디어학회 2010 한국멀티미디어학회 국제학술대회 Vol.2010 No.-

The effective Young's modulus of a microfibril surrounded by water may be simply calculated by using the upper (Voigt) and lower (Reuss) bounds. The result is compared to the Young's modulus estimated by using the Steered Molecular Dynamics (SMD) (Zhang et al. 2007). Our result shows 9.2% difference from the result estimated by SMD, but the steps using these bounds are much simpler than SMD..

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.

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.

유아 언어영재 판별에서 프로젝트 스펙트럼(Project Spectrum)의 활용에 대한 기초연구

장영숙,황윤세 한국영유아보육학회 2003 한국영유아보육학 Vol.0 No.33

The identification of verbally gifted children during early childhood is very important for developing their potential in the society. Nonetheless, most researchers preferred to study the gifted of mathematics and science in the primary and secondary levels where reliable predictions of gifted may be made. Comparatively little work has been done in this area. Verbal Giftedness of young children is still developing and less stable than that of older children, and this prevents us from making firm and accurate identification. Project Spectrum can be used for the alternative assessment for the identification of verbally gifted children. The advantages of the Project Spectrum approach for the identification of verbally gifted children are as follows: First, the Spectrum approach can provide a useful means for assessing young verbally gifted children who have not demonstrated high ability on traditional identification method. Second, the Spectrum approach can blur the line dividing curriculum and assessment and thus can assess the learning process of young children.. Third, the Spectrum approach can embed assessments in meaningful, real-world activities Fourth, the Spectrum approach can be a more accurate predictor of potential by linking diagnosis and instruction. Thus, it can make us provide an educational treatment effectively for young verbally gifted children. Fifth, the Spectrum approach can lead individualized education by the early identification of young verbally gifted children.

비공식 사회지원망 종류와 삶의 만족도 : 전기 노인과 후기 노인의 차이를 중심으로

김영범(Kim, young Bum),윤혜경(Yoon, Hye-Gyung),윤현숙(Yoon, Hyun Sook) 지역사회학회 2019 지역사회학 Vol.20 No.3

본 연구의 목적은 비공식 사회지원망과 노인이 인식하는 삶의 만족도 사이의 관계가 전기 노인과 후기 노인에게서 차이를 보이는지 분석하는데 있다. 본 연구는 비공식 사회지원망을 가족·혈연지원망과 친구·이웃지원망으로 구분한 후 각각의 크기가 삶의 만족과 유의미한 관계를 보이는지 전기 노인과 후기 노인으로 나누어 분석하였다. 본 연구에서는 춘천 지역 거주 65세 이상 노인 1,000명에 대한 조사 결과를 활용하여 분석을 실시하였다. 본 연구의 주요한 결과는 다음과 같다. 첫째, 나이가 들수록 삶의 만족도는 증가하지만 후기 노년기에는 나이와 유의미한 관계를 보이지 않는 것으로 나타났다. 건강관련 요인 중 외로움, 우울이, 사회경제적 요인 중 소득은 노인의 삶의 만족도에 영향을 주는 것으로 나타났다. 둘째, 지원망 전체 크기는 노인의 삶의 만족과 유의미한 관계를 보이는 것으로 나타났다. 셋째, 전기 노인의 경우 가족·혈연이나 친구·이웃지원망의 크기가 삶의 만족과 유의미한 관계를 보이지 않는 반면 후기 노인의 경우 가족 지원망의 크기는 삶의 만족도와 유의미한 관계를 보이는 것으로 나타났다. The purpose of the study was to analyze the relationship between the types of informal social support networks and level of life satisfaction perceived by the elderly. The study focused on the difference of the relationship between the young old and old-old elderly group. This study divided informal social support network into family support network and non-family support network, and analyzed the relationship of each social support network size and life satisfaction in young old and old-old groups. In this study, we analyzed the survey results of 1,000 elderly people over 65 years of age living in Chuncheon. The main results of this study were as follows. First, life satisfaction increased with age, but there was no significant relationship with age in later age. Income among socioeconomic factors and loneliness and depression among health-related factors were found to affect the life satisfaction of the elderly. Second, the overall size of the support network was found to have a significant relationship with the life satisfaction of the elderly. Third, the size of family or non-family support network showed no significant relationship with life satisfaction in the young old elderly group, while the size of family support network had a significant relationship with life satisfaction in the old-old elderly group.

A Case of Urethral Stent for Recurrent Urethral Stricture and Penile Prosthesis for Erectile Dysfunction

Jung, Gyung-Woo,Song, Young-Jin,Park, Young-Ho,Kwon, Heon-Young,Yoon, Jin-Han 동아대학교의과대학 1992 동아의대학술지 Vol.4 No.1

유한요소법에 의한 골강도와 micro-CT 지표 및 골밀도간의 상관관계

윤영남,이완,이병도 대한구강악안면방사선학회 2007 Imaging Science in Dentistry Vol.36 No.1

Purpose : Bone mineral density (BMD) and bone microarchitecture are important determinants for bone strength. Recently micro-CT have provided possibilities for measuring a variety of structural indices to characterize bone microarchitecture. The objective of this study was to compare the BMD and micro-CT parameters with Young's modulus calculated by finite element analysis(FEA) for the evaluation of bone strength. Materials and Methods : Bone specimens were obtained from the 18 female rabbits aged 16 weeks. Of those, 36 samples (right and left femur) were selected for 3D micro-CT analysis (ANT^(TM), SKYSCAN, Belgium) and BMD by PIXImus 2 (GE Lunar Co. USA). Five microstructural parameters of micro-CT, such as trabecular thickness (Tb.Th), bone specific surface (BS/BV), percent bone volume (BV/TV), structure model index (SMI) and degree of anisotropy (DOA) were studied. Young's modulus was obtained by software program (ANSYS 9.0, ANSYS Inc, Canonsburg, PA) based on micro-CT three dimensional images. Results : Young's modulus assessed by FEA correlated significantly with Tb.Th, BV/TV, BS/BV and SMI respectively. Young's modulus showed higher correlation with these microstructural parameters of micro-CT than BMD. Microstructural parameters except DOA showed significant correlations within the examined group. Conclusion : The microarchitectural parameters of micro-CT and BMD represented some informations in the evaluation of bone strength assessed by FEA. (Korean J Oral Maxillofac Radiol 2007; 37: 53-9)

청년기 남자의 항산화 비타민 섭취수준 및 관련 식행동 비교

박영숙,윤선영 순천향대학교 기초과학연구소 2002 순천향자연과학연구 논문집 Vol.8 No.1

A survey was performed to 250 male young men who were living alone and shared living with friends in Chungnam province. Their average age was 22.6 years old, height was 171.8 ㎝, weight was 65.6 ㎏ and BMI was 22.2. Comparing the prevalence of drinking, smoking and exercise, there were significantly different between living alone subjects and shared-living ones. The main value toward eating/meals was for hungry solution. And we found many significant differences by living with or without companion. When young men living without companions, they showed to be more in regular mealtimes, no-skipped meals, breakfast eating, adequate food amounts, eating-outs, etc. and to be less in pleasant mealtimes, various foods, snacking and especially late snacks. The good food intake pattern were highly scored in the alone-living group than the shared-living group, whereas the bad food intake pattern were also highly scored in the alone-living group than the other. The latter might be due to the more food exposures because of companions. These findings could conclude that dietary behaviors of the young living alone were evaluated as good enough.

BMP test를 통한 음폐수와 하수슬러지의 병합소화 특성 평가

이수영ㆍ윤영삼ㆍ강준구ㆍ김기헌ㆍ신선경(Su young LeeㆍYoung Sam YoonㆍJun Gu KangㆍKi Heon KimㆍSun Kyoung Shin) 유기성자원학회 2016 유기물자원화 Vol.24 No.1

혐기성 소화의 주요 조건 중 하나인 C/N비의 경우 하수슬러지는 5.40으로 낮게 나타난 반면 음폐수(Food waste leachate)는 21.84로 높게 나타났다. C/N비가 낮을 경우 혐기성소화의 저해 요인으로 작용될 수 있기 때문에 음폐수의 높은 유기물 농도 및 C/N 비를 활용하여 메탄가스 발생량 증가시킬 수 있었다. Tchobanoglous이 제안한 이론적 메탄가스 발생량 예측수식을 적용하여 메탄 및 바이오가스 발생량을 산정한 결과 하수슬러지 단일 혐기소화의 경우 305.6 mLㆍCH4/gㆍVS, 689.4 mLㆍCH4/gㆍVS의 메탄, 바이오가스가 발생하였고 음폐수 : 하수슬러지를 1:9로 혼합한 시료는 약 322 mLㆍCH4/gㆍVS, 3:7시료에서는 약 354 mLㆍCH4/gㆍVS, 5:5시료에서는 약 386 mLㆍCH4/gㆍVS의 메탄가스가 발생하는 것으로 분석되었다. BMP 실험 결과 1:9, 3:7, 5:5 비율로 병합 처리한 경우 각각 약 233, 298, 344 mLㆍCH4/gㆍVS의 메탄가스가 발생하였다. 따라서 음폐수의 혼합비율이 높아질수록 메탄가스 발생량은 증가하였고 하수슬러지와 음폐수의 혼합 비율에 따른 병합처리 시 하수슬러지 단독처리에 비해 다량의 메탄가스가 발생되었다. BMP 실험을 통해 생산된 메탄가스의 누적생산 곡선을 Modified Gompertz model과 first order kinetic model에 적용하여 추정한 결과, 메탄생성량은 Modified Gompertz model에서는 238.5, 302.3, 353.6 mL/gㆍVS 발생하였고 first order kinetic model에서는 242.8, 312.5, 365.5 mL/gㆍVS로 음폐수와의 혼합비율이 증가할수록 높게 나타났으며, 최대 메탄생성속도의 경우 3:7비율에서 48.2 mL/gVSㆍday로 최대 메탄생성 속도를 보였다. first order kinetic model의 1차 반응속도상수 k값은 1:9, 3:7, 5:5 비율에 따라 0.32, 0.22, 0.08day-1 나타났다. 1차 반응속도 상수의 경우 음폐수의 혼합비율이 낮을수록 높게 나타났다. Modified Gompertz와 first order kinetic model 모두 실험결과를 잘 모사하였으며, 실험결과와 모의결과의 적합도를 나타내는 상관계수(R2)의 경우 0.92∼0.98으로 높은 상관성을 나타내었다. We mix food waste leachate and sewage sludge by the proportion of 1:9, 3:7 and 5:5. It turns out that they produced 233, 298 and 344 CH4ㆍmL/gㆍVS of methane gas. The result suggests that as the mixing rate of food waste leachate rises, the methane gas productions increases as well. And more methane gas is made when co-digesting sewage sludge and food waste leachate based on the mixing ratio, rather than digesting only sewage sludge alone. Modified Gompertz and Exponential Model describe the BMP test results that show how methane gas are produced from organic waste. According to the test, higher the mixing rate of food waste leachate is, higher the methane gas productions is. The mixing ratio of food waste leachate that produces the largest volume of methane gas is 3:7. Modified Gompertz model and Exponential model describe the test results very well. The correlation values(R2) that show how the results of model prediction and experiment are close is 0.92 to 0.98.