영흥대교 유지관리 및 상태평가 시스템 개발

주관정(Joo Guan Jung),김동욱(Kim Dong Wook),천영철(Chun Young Chul),여영건(Lu Yung Chien) 대한토목학회 2005 대한토목학회 학술대회 Vol.2005 No.10

금속의 EAM해석

정영관(Young-guan Jung),김경훈(Kyoung-hoon Kim),김세웅(Se-woong Kim) 한국자동차공학회 2002 한국자동차공학회 지부 학술대회 논문집 Vol.- No.-

Numerical analysis on the atomic and molecular level is necessary as properties of materials are based on the correlation between atoms or molecules. The embedded atom method established on density functional theory was developed as a new means for calculating various properties and phenomena of realistic metal systems. In this study, we had corrected constitutive formulae and parameters, and developed the program on the nickel and the palladium for the purpose of doing Embedded Atom Method analyses on metals. And then we have computed the properties of the nickel and the palladium on the fundamental scale of the atomic structure. As a result, simulated ground state properties, such as the lattice constant, elastics constants and sublimation energy, show good agreement with Daw's simulation data and with experimental data.

압연가공판재의 수소저장과 팽창거동과의 관계

정영관(Young Guan Jung),김경훈(Kyoung Hoon Kim),이근진(Keun Jin Lee) 한국수소및신에너지학회 2001 한국수소 및 신에너지학회논문집 Vol.12 No.2

In order to study the relation between expansion of the specimen and the hydrogen absorption rate, thin palladium plates with cold rolling were used. Thin palladium plates were hydrogenated in the 0.1mol H₂SO₄ electrolyte by electrochemical method. The expansion behavior on hydrogen absorbing can be obtained by X-ray diffraction analysis and by micrometer measurement. It is noted that the expansion rate of Palladium specimens in thickness direction is larger than in length and width direction. The lattice constants increase quickly with increasing hydrogen absorbing rate up to 0.5, but above the rate they keep constant. Also the clues for plastic deformation, such as slip lines and voids, were observed in abundantly even though the plates were hydrogenated once.

디지털 위성중계기에 대한 시스템 단위의 우주환경 검증 시험

송영중(Young-Joong Song),김정호(Jung-Ho Kim),이수현(Sue-Hyun Lee),서학금(Hak-Geum Seo),신관호(Guan-Ho Shin),진봉철(Bong-Chul Jin) 한국통신학회 2013 韓國通信學會論文誌 Vol.38 No.12(융합기술)

국내기술을 적용하여 설계 및 제작한 디지털중계기 우주인증모델 개발은 개발과정중 사전에 예측하지 못한 다양한 시행착오를 겪었다. 특히 진공이라는 특수환경에 대한 열설계 경험 부족으로 인하여 1차 진행된 열진공 시험 시 설계/조립/시험구성 오류사항들을 식별하게 되었고 중계기에 대한 성능검증을 성공적으로 수행할 수 없었기 때문에 사전에 계획되지 않은 2차 열진공 시험을 수행하게 되었다. 본 논문은 디지털 중계기의 1차 열진공 시험 시 발생한 오류사항에 대한 분석과 2차 시험시 적용한 해결방법과 그 결과를 제시한다. 이를 통하여 본 과제의 2차 우주인증모델 개발시 열적 성능이 개선된 디지털중계기를 얻을 수 있을 것이다. 또한 추후 국내외에서 개발될 중계기 탑제체의 열진공 시험시 참고자료로서 활용될 수 있을 것이다. EQM Model Digital transponder applying the Korean"s own designing and manufacturing technology has gone through a series of trials and errors during the development. In particular, lack of thermal designs expedience for the vacuum causes variety of errors in designing, assembling transponder and setting up the test at the first thermal vacuum test (TVAC). Since the first TVAC test could not accomplished its aims successfully, so the second TVAC should be performed as make up test with revised Digital transponder. In this paper, the defects that identified in the first TVAC are analyzed and applied solutions and its results at the second TVAC are presented. Using the lessons from the first and second TVAC, we will be able to make more reliable digital transponders in the next phase of project. In addition it also be useful as a reference when we design another satellite payloads.

유한요소법을 통한 Butterfly Valve의 Rubber-Metal Seat 복합해석

박영철(Young Chul Park),정지훈(Ji Hoon Jung),김동관(Dong Guan Kim),송학관(Xueguan Song) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.4

흉부 CT검사 시 검사부위를 벗어난 Topogram 부위에 Automatic Exposure Control 적용이 선량 및 화질에 미치는 영향

박관중(Guan Jung Park),김영옥(Young Ok Kim),여상근(Sang Geun Yeo),대창민(Chang Min Dae),민관홍(Kwan Hong Min) 대한전산화단층기술학회 2011 대한CT영상기술학회지 Vol.13 No.2

목적 임상에서 많이 시행하고 있는 흉부 computed tomography(이하 CT) 검사 시, 세 개의 각기 다른 CT장비 제조사의 automatic exposure control(이하 AEC) system을 인체 등가phantom에 적용하여, 검사부위를 벗어난 topogram을 검사하였다. 검사부위를 벗어난 topogram에서 AEC작동유무 및 CT dose index volume(이하 CTDI) 변화를 측정하고, 영상의 노이즈값의 비교를 통하여 선량 및 화질 변화를 알아보고자 하였다. 대상 및 방법 사용된 각 장비 회사별 CT 장비는 Brilliance 64 MDCT(Philips healthcare, 이하 P사), LightSpeed VCT XT 64 MIDCT(General Electric Medical System, 이하 G사), Somatom Definition Dual CT(Siemens Healthcare, 이하 S사)를 사용하였다. Rando phantom을 대상으로 하여 본원에서 흉부 검사 범위로 정하고 있는 성대에서 부신이 충분히 포함된 topogram을 정상군으로 정하고, 정상군과 비교하여 폐첨부에서 머리 방향쪽으로 2cm 검사부위를 벗어난 군을 A군, 4cm는 B군, 6cm는 C군, 8cm를 D군으로 대조군을 정하였다. 선량 평가를 위해 각 장비 제조회사에서 제공하는 CTDI값과 ionization chamber를 이용하여 CTDI값을 실측한 후, 정상군의 CTDI값을 기준으로 대조군의 CTDI 증감률을 산출하였다. 화질 평가는 AAPM phantom을 이용하여 정상군 및 대조군 실험 영상의 6시 방향 1/4지점에서 4×4cm의 크기의 region of interest(이하 ROI)를 설정하여 모든 slice의 평균오차의 값을 노이즈값으로 계산하여 평가하였다. 결과 정상적인 topogram과 검사부위를 벗어난 topogram의 AEC적용 결과는 P사의 경우는 ACS만 적용 시 노이즈값은 정상군은 12.9, A군은 약 12.7(p=0.0273, B군은 약 12.6(p=0.0195), C군은 약 12.2(p=0.002), D군은 약 12.l(p=0.002)로 측정되었으며, 대조군의 CTDI 증감률은 정상군과 비교하여 각 군에서 약 8.9%, 11.1%, 14.4%, 15.6% 증가하였다. ACS combined Z-DOM 적용 시에는 정상군 비교하여 CTDI 증감률은 각 군에서 약 3.0%, 4.0%, 4.0%, 5.0% 증가하지만, 노이즈값은 각 군에서 약 13.3, 약 13.2(p=0.0216), 13.1(p=0.0078), 12.9(p=0.0195), 12.9(p=0.0039)로 측정되었다. ACS combined D-DOM 적용 시에는 CTDI 증감률은 정상군 비교하여 각 군에서 약 0.9%, 1.8%, 1.8%, 2.7% 증가하였고, 노이즈값은 정상군은 약 12.7, 대조군은 약 12.6(p=0.0301), 12.5(p=0.0392), 12.5(p=0.0391), 12(p=0.002)로 통계학적으로 유의한 차이가 없었다. S사의 경우에는 노이즈값은 각 군에서 약 8.0, 7.9(p=0.0376), 7.6(p=0.0277), 7.5(p=0.002), 7.3(p=0.002)로 통계학적으로 유의한 차이가 없었다. CTDI 증감률은 정상군 비교하여 각 군에서 약 1.2%, 3.4%, 2.3%, 6.9% 증가하였다. G사의 경우는 Auto mA 적용 시, 정상군의 노이즈값은 약 45.0, A군은 약 44.1(p<0.0001), B군은 약 44.1(p<0.0001), C군은 약 44.1(p<0.0001), D군은 약 44.1(p<0.0001)으로 대조군에서는 모두 동일한 결과로 측정되었다. 정상군과 비교하여 대조군 모두 통계학적으로 유의한 차이가 없이, CTDI 증감률은 정상군과 비교하여 모든 대조군에서 동일하게 약 8.1% 증가를 보였다. 결론 검사부위를 벗어난 topogram을 얻은 후, topogram에 포함되지 않은 영역에 AEC를 적용하게 되면, 각 장비 회사마다 다소 차이는 있지만 영상의 질적 차이 없이 방사선 피폭선량이 최소 약 0.9%에서 최대 15.6% 증가하였다. 따라서 AEC를 적용 시 정확한 환자의 위치잡이가 선행되어야 topogram을 통해 정확한 정보를 얻을 수 있다. 그 정보를 바탕으로 AEC가 올바르게 동작하여 선량의 최적화를 달성할 수 있을 것으로 사료된다. I. Purpose The purpose of this study is to investigate the change of radiation dose and image quality in outside topogram of scan range applying automatic exposure control (AEC) through phantom study in chest CT. II. Meterial and Methods A Rando anthropomorphic chest phantom and AAPM phantom was scanned on a 64 multi detector CT using the AEC systems from three different manufacturers: General Electric Healthcare, Philips Medical Systems and Siemens Medical Solutions. A general scanning protocol was created for each examination where as many as possible of the scanning parameters were set equal. Divided into 5 groups according to include and not be scan range of topogram. Topogram, normally including scan range, is defined normal group. If not was control group, the group which was 2 an outside topogram of scan range toward head from lung apex was designated as A group, B group in 4 cm off, C group in 6 an off, and D group in 8 an off. CTDI was measured using ionization chamber and provided by CT modality. CTDI fluctuation ratios of control groups were calculated based on the values of CTDI in normal group. For the evaluation of image quality, mean error value was assessed by the image noise from AAPM phantom. III. Result As a result of application of AEC to normal and control groups, in case of P, when applying only ACS, noise of normal group was 12.9, 12.7(p=0.0273) in A group, 12.6(p=0.0195) in B group, 12.2(p=0.002) in C group, 12.1(p=0.002) in D group. CTDI fluctuation ratios of control group was increased by 8.9%i, 11.1%, 14.4%, 15.6% respectively in each group compared to normal group. When applying ACS combined Z-OOM, the CTDI fluctuation ratios of control groups was increased by 3.0%, 4.0%, 4.0%, 5.0% respectively, compared to normal group. However, noise was appeared to be 13.3, 13.2(p=0.0216), 13.1(p=0.0078), 12.9(p=0.0195), 12.9(p=0.0039). When applying ACS combined D-DOM, the CTDI fluctuation ratios was increased by 0.9%, 1.8%, 1.8%, 2.7% while noise value in normal group was 12.7, 12.6(p=0.0301), 12.5(p=0.0392, 12.5(p=0.0391), 12(p=0.002). No statistical significant difference was found. In case of S, noise appeared to be 8.0, 7.9(p=0.0376), 7.6(p=0.0277), 7.5(p=0.002), 7.3(p=0.002) respectively in each group leading to no statistical significant difference. CTDI fluctuation ratios, comparing to normal group, was increased by 1.2%, 3.4%, 2.3%, 6.9%. In case of G, when applying AutomA, the noise of normal group was measured to be 4.0, and 44.1(p<0.0001) in A~D control groups, Compared to normal group, there was no statistical significant difference in control groups, and also the fluctuation ratio (%) of CTDI showed the same ratio of 8.1% in all control groups. IV. Conclusions Radiation dose by different mmufacturer was increased by at minimum 0.9% up to at maximum 15.6%. And it was little difference of image quality found at all. Consequently, projection of topogram, normally included scan range, is very important applying AEC in CT examination.

Articles : Life Science ; Preparation and in Vivo Evaluation of Piroxicam-Loaded Gelatin Microcapsule by Spray Drying Technique

( Ming Guan Piao ),( Chan Woo Yang ),( Dong Xun Li ),( Jong Oh Kim ),( Ki Young Jang ),( Bong Kyu Yoo ),( Jung Ae Kim ),( Jong Soo Woo ),( Won Seok Lyoo ),( Sung Soo Han ),( Yong Bok Lee ),( Dae Duk K 영남대학교 약품개발연구소 2008 영남대학교 약품개발연구소 연구업적집 Vol.18 No.-

The Design of an Intelligent Aquaculture Systsm Based on Iot and Lora Technologies

( Yun-hsiang Tang ),( Xiang-guan Deng ),( Ming-yen Lin ),( Yi-jung Pai ),( Chao-wang Young ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

In Taiwan, the export-oriented economy of traditional aquaculture is faced with the harshest conditions, such as environmental pollution, diseases and drug overdose. In addition, the traditional aquaculture fields are usually open-air for costing a lot on employing labors. Consequently, it is necessary to set up an intelligent aquaculture system for solving the above problems effectively. This study which was based on these technologies of internet of things (IoT), cloud computing and Long Range Low Power Wide Area Network (LoRa LPWAN), was designed a daily management system for auto-controlling on production planning, energy conservation and reducing labor costs. The users can operate this system which can both monitor the water quality and control these real-time aquaculture parameters (temperature, pH, illuminance and electrical conductivity) by simply using the remote user interface. This system is a modular design that is user-friendly and portable. After all, we expect that it will be great helpful to construct an automatic control platform for improving aquaculture efficiency in future.

지하철 내 공기 조사

서은경,권은경,김영희,김진,김경충,김정수,김혜진,이진희 梨花女子大學校 藥學硏究所 1987 梨花藥學硏究 Vol.- No.26

In order to study the problems of air pdlution whose reduction can be achieved by adequate pollution control, and an objective appreciation of the problems and consequences by government industry, and the consumer, we have some tests for the air of subway. Experiments contained the measuring of the number of colony of Bacteria, the quantity of CO_2, pH, dust, air temperature, air moisture and kata cooling power. From this kata cooling power we calculated the air movement, and from the chart, we obtained the effective temperature. According to the results, the air of subway was polluted by dust, and most of the sampling points were within the comfort zone or comfort line.

디젤기관에 대한 앳킨슨사이클 구성과 사이클의 열역학적 해석에 관한 연구

김철수,정영관,장태익,Kim Chul Soo,Jung Young Guan,Jang Tae lk 한국마린엔지니어링학회 2005 한국마린엔지니어링학회지 Vol.29 No.2

The present study composed a diesel-atkinson cycle of high expansion as a method of achieving high efficiency in diesel cycle engines. It also interpreted the cycle engine thermodynamically analysis to determine the possibility of the improvement of thermal efficiency and clarified the characteristics of several factors . According to the result of theoretical analysis, heat efficiency was highest when expansion-compression ratio Reど:1. In addition. diesel engines with high apparent compression ratio had higher expansion-compression ratio than otto engines and consequently their effect of high expansion was high. which in turn enhanced thermal efficiency. When the atkinson cycle was implemented in a real diesel engine by applying the miller cycle through the variation of the closing time of the intake valve, the effective compression ratio and the quantify of intake air decreased and as a result, the effect of high expansion was not observed. Accordingly. the atkinson cycle can be implemented when the quantity of intake air is compensated by supercharge and the effective compression ratio is maintained at its initial level through the reduction of the clearance volume. In this case. heat efficiency increased by $4.1\%$ at the same expansion-compression ratio when the apparent compression ratio was 20 and the fuel cut off ratio was 2. As explained above, when the atkinson cycle was used for diesel cycle. heat efficiency was improved. In order to realize high expansion through retarding the intake value closing time, the engine needs to be equipped with variable valve timing equipment, variable compression ratio equipment and supercharged Pressure equipment. Then a diesel-atkinson cycle engine is realized.