양·배수장에 이용되는 IoT센서의 진단 특성

이병준, 김난영, 윤성수 충북대학교 농업과학기술연구소 2022 農業科學硏究 Vol.38 No.1

본문참고

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.

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.

Anatomical distribution and detection rate of colorectal neoplasms according to age in the colonoscopic screening of a Korean population

Suk-young Lee,Wan Hee Song,Sang Cheul Oh,Byung-Wook Min,Sun Il Lee 대한외과학회 2018 Annals of Surgical Treatment and Research(ASRT) Vol.94 No.1

Purpose: Because data as a basis for the determination of proper age and modality for screening of colorectal neoplasms is lacking, we evaluated detection rates and anatomical distribution of colorectal neoplasms according to age in healthy individuals who underwent total colonoscopy for health checkup. Methods: A total of 16,100 cases that had received the colonoscopic examination from January to December in 2014 were analyzed. The total number of individuals who received total colonoscopy were divided by the number of individuals harboring colorectal adenoma to calculate the detection rate of colorectal adenoma. Individuals ≤50 years old were classified as young-age group and aged >50 were old-age group. Differences in anatomical locations of colorectal neoplasms were analyzed in the 2 age groups by chi-square test. Risk factors for colorectal adenoma in each age group were analyzed using univariate and multivariate logistic regression analyses. Results: Detection rates of colorectal adenoma were 13.7% in all cases and 12.8% for those in their 40’s. The main anatomical location of colorectal adenoma was proximal colon in both age groups (P < 0.001). Hyperplastic polyp was mainly distributed to the distal colon in both age groups (P < 0.001). Distal colon was the major site for colorectal cancer in the old-age group (P = 0.001). Proximal location of neoplasms was a risk factor for colorectal adenoma in both age groups with multivariate analysis. Conclusion: These data could be the bases for earlier initiation of screening for colorectal neoplasms with total colonoscopy to detect clinically significant colorectal polyps.

플립칩 패키지의 신뢰성 향상에 관한 연구

이선병(Sun Byung Lee),김종민(Jong Min Kim),이성혁(Seong Hyuk Lee),신영의(Young Eui Shin) 한국생산제조학회 2007 한국공작기계학회 춘계학술대회논문집 Vol.2007 No.-

A solder joint fatigue failure of flip chip (FC) package is mainly caused by the thermal stress due to the coefficient of thermal expansion (CTE) mismatch between the silicon die and the substrate. A nonlinear finite element analysis was conducted to investigate solder joint reliability under thermal cycling loading for FC assemblies without and with underfill. The effect of the solder joint height and thermomechanical properties such as CTE and Young's modulus on reliability of FC package. For parametric study, a finite element analysis are performed for seven different CTEs and five different Young's moduli of underfill. The concentrated Von Mises stress of the underfilled FC assembly was approximately 85% comparing that of FC assembly without underfill. Also, the concentrated stresses in the solder joint was decreased with increasing solder joint height. In addition, it is found that the solder joint reliability was improved with increasing Young's Modulus of underfill. Furthermore, the solder joint reliability was improved as the CTE was close to that of solder.

Adipose sirtuin 6 drives macrophage polarization toward M2 through IL-4 production and maintains systemic insulin sensitivity in mice and humans

Song, Mi-Young,Kim, Sang Hoon,Ryoo, Ga-Hee,Kim, Mi-Kyung,Cha, Hye-Na,Park, So-Young,Hwang, Hong Pil,Yu, Hee Chul,Bae, Eun Ju,Park, Byung-Hyun Nature Publishing Group UK 2019 Experimental and molecular medicine Vol.51 No.5

<▼1><P>Adipose tissue inflammation is a reproducible feature of obesity and obesity-linked insulin resistance. Although sirtuin 6 (Sirt6) deficiency has previously been implicated in diet-induced obesity and systemic insulin resistance, the adipocyte-specific role of Sirt6 in the regulation of adipose tissue inflammation and systemic metabolic dysfunction in mice fed normal chow and in humans remains elusive. Here, using <I>Adipoq-Cre</I>-mediated adipocyte-specific Sirt6 knockout (aS6KO) mice, we explored whether adipocyte Sirt6 inhibits adipose tissue inflammation and its underlying mechanism. aS6KO mice fed normal chow gained more body weight and fat mass than wild-type mice and exhibited glucose intolerance and systemic insulin resistance. Measurement of plasma and tissue cytokines and flow cytometric analysis of adipose stromal vascular cells indicated a decrease in alternatively activated M2 macrophages in the adipose tissue of aS6KO mice. Mechanistically, Sirt6 regulated the expression of the canonical type 2 cytokine IL-4 by adipocytes in a cell autonomous manner, which in turn affects M2 macrophage polarization. Consistent with animal experimental data, the degree of obesity and insulin resistance demonstrated by the body mass index, fasting blood glucose and HbA1c correlated negatively with the expression of Sirt6 in human visceral fat tissues. Collectively, these results suggest that adipocyte Sirt6 regulates body weight gain and insulin sensitivity independent of diet, and the increased IL-4 production by Sirt6 and resultant M2 polarization of adipose tissue macrophages may attenuate proinflammatory responses in adipose tissue.</P></▼1><▼2><P><B>Obesity and diabetes: A control protein in fat</B></P><P>A protein in adipose tissue (composed of fat cells) helps protect against inflammation and the development of resistance to insulin that develops in obesity and can lead to type 2 diabetes. Researchers in South Korea, led by Eun Ju Bae at Woosuk University, Wanju, and Byung-Hyun Park at Chonbuk National University, Jeonju, investigated the role of Sirt6 in mice and in human adipose tissue. Deleting the mouse gene that codes for Sirt6 in adipocytes promoted the impaired response to insulin and associated increase in blood glucose levels that are two key aspects of diabetes. Changes in biochemical signaling pathways controlling immune cells called macrophages were implicated in these effects and suggest an anti-inflammatory role for Sirt6. Analysis of human adipose tissue supported these findings. The research will help understand how obesity promotes type 2 diabetes.</P></▼2>

Fe-0.7%C-2.3%Si강의 미세조직과 기계적 성질에 미치는 잔류 오스테나이트 변태 거동

손제영 ( Je Young Son ),권도영 ( Do Young Kwon ),김지훈 ( Ji Hun Kim ),김원배 ( Won Bae Kim ),예병준 ( Byung Joon Ye ) 한국주조공학회 2012 한국주조공학회지 Vol.32 No.3

This steel has been synthesized integrating concepts from Austempering Ductile Cast Iron (ADI) technology. While ADI has excellent mechanical and physical properties, the Young`s modules of ADI is approximately 20% lower than steel. In addition, the presence of graphite nodules in ADI can be sites of crack initiation, where fracture takes place at graphite matrix interface. Because of this limitations of ADI, there has been a growing interest in austempered steels as structural materials in resent years. In this investigation, a new steel with microstructure composed of ferrite and austenite and with simultaneous high tensile strength (1,150MPa) and high ductility (33%) was developed. The goal of this investigation is to obtain a better understanding of deformation and transformation behaviour in high carbon retained austenite(γHC) and over-saturated ferrite(α) during the plastic deformation. A detailed study of the microstructure of this steel was carried out by means of X-ray diffraction (XRD) and electron back scattering diffraction (EBSD) technic. In this way it was shown that BCC phase (BCC) took up the larger part of the nominal strain whereas the a part of retained austenite responded to the mechanincal load by partial martensite transformation, and misorientation change in the retained austenite after plastic strain could be attributed to the large elongation.

Anatomical distribution and detection rate of colorectal neoplasms according to age in the colonoscopic screening of a Korean population

Lee, Suk-young,Song, Wan Hee,Oh, Sang Cheul,Min, Byung-Wook,Lee, Sun Il The Korean Surgical Society 2018 Annals of Surgical Treatment and Research(ASRT) Vol.94 No.1

<P><B>Purpose</B></P><P>Because data as a basis for the determination of proper age and modality for screening of colorectal neoplasms is lacking, we evaluated detection rates and anatomical distribution of colorectal neoplasms according to age in healthy individuals who underwent total colonoscopy for health checkup.</P><P><B>Methods</B></P><P>A total of 16,100 cases that had received the colonoscopic examination from January to December in 2014 were analyzed. The total number of individuals who received total colonoscopy were divided by the number of individuals harboring colorectal adenoma to calculate the detection rate of colorectal adenoma. Individuals ≤50 years old were classified as young-age group and aged >50 were old-age group. Differences in anatomical locations of colorectal neoplasms were analyzed in the 2 age groups by chi-square test. Risk factors for colorectal adenoma in each age group were analyzed using univariate and multivariate logistic regression analyses.</P><P><B>Results</B></P><P>Detection rates of colorectal adenoma were 13.7% in all cases and 12.8% for those in their 40′s. The main anatomical location of colorectal adenoma was proximal colon in both age groups (P < 0.001). Hyperplastic polyp was mainly distributed to the distal colon in both age groups (P < 0.001). Distal colon was the major site for colorectal cancer in the old-age group (P = 0.001). Proximal location of neoplasms was a risk factor for colorectal adenoma in both age groups with multivariate analysis.</P><P><B>Conclusion</B></P><P>These data could be the bases for earlier initiation of screening for colorectal neoplasms with total colonoscopy to detect clinically significant colorectal polyps.</P>

유한요소법에 의한 골강도와 micro-CT 지표 및 골밀도간의 상관관계

윤영남,이완,이병도,Yoon, Young-Nam,Lee, Wan,Lee, Byung-Do 대한영상치의학회 2007 Imaging Science in Dentistry Vol.37 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 PIXlmus 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 rnicrostructural parameters of micro-CT than BMD. Microstructural parameters except DOA showed significant correlations within the examined group. Conclusion The microarchitectural parameters o( micro-CT and BMD represented some informations in the evaluation of bone strength assessed by FEA.