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박해천,강성군 조선대학교 생산기술연구소 1999 生産技術硏究 Vol.21 No.1
Existing production methods and management patterns come to a crisis to do with diverse demands of customers and rapid changes of outward circumstances of these days. To face such crisis. information important for production should be gathered and managed, and it is most effective to build computerized information management system. As it was in the past when mass production was preferred. thorough knowledge of material flow, one of most important factors in significant these days when small production of various items to meet customers' diverse demands. In this paper, a program is suggested where the theory of MRP-II(Manufacturing Resource Planning) - a production management system, the heart in making integration of production information, - is applicable, and methodology on technical integration of information on work flow between client and servo is also suggested with easy interface and easy input and output of data, which easiness is secured in the suggested program.
Shim, Ji Sung,Kwon, Tae Gyun,Rha, Koon Ho,Lee, Young Goo,Lee, Ji Youl,Jeong, Byong Chang,Kim, Jae Yoon,Pyun, Jong Hyun,Kang, Sung Gu,Kang, Seok Ho KOREAN ACADEMY OF MEDICAL SCIENCE 2017 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.32 No.10
<P>The aim of our study was to evaluate intermediate-term oncologic outcomes, predictive factors for recurrence, and recurrence patterns in a multicenter series of patients treated with robot-assisted radical cystectomy (RARC) for urothelial carcinoma (UC) of the bladder. Between 2007 and 2015, 346 patients underwent RARC at multiple tertiary referral centers in Korea. Descriptive statistics were used for demographics and perioperative variables. Survival and recurrence were estimated with Kaplan-Meier analysis. Logistic regression models were used to determine predictors of recurrence. Median follow-up was 33 months (interquartile range [IQR], 7–50). The numbers of patients with organ-confined and lymph node (LN)-positive disease were 237 (68.4%) and 68 (19.7%), respectively. LN density (1–20 vs. > 20) was 13.6% and 6.1%, with a median of 17 nodes removed (IQR, 9–23). In logistic regression analysis, type of LN dissection, and pathologic tumor stage were significant predictors of cancer recurrence and death from cancer. Local, distal recurrence and secondary UC occurred in 7 (2.0%), 53 (15.3%), and 4 (1.2%) patients, respectively. The 5-year overall survival (OS), cancer-specific survival (CSS), and recurrence-free survival (RFS) were 78%, 84%, and 73%, respectively. At last follow-up, RFS for extended pelvic LN dissection vs. standard pelvic LN dissection was 70% and 47% (<I>P</I> = 0.038). In addition, at last follow-up, LN density (0 vs. 1–20 vs. over 20) was 67%, 41%, and 29%, respectively (<I>P</I> < 0.001). Patients undergoing RARC in this multi-institutional cohort demonstrated intermediate-term oncologic outcomes, predictive factors for recurrence, and recurrence patterns that were not unusual.</P>
Reliability Verification of FLUKA Transport Code for Double Layered X-ray Protective Sheet Design
Sang Sik Kang(강상식),Seung Wook Heo(허승욱),Il Hong Choi(최일홍),Jae Hoon Jun(전제훈),Sung Woo Yang(양승우),Kyo Tae Kim(김교태),Ye Ji Heo(허예지),Ji Koon Park(박지군) 한국방사선학회 2017 한국방사선학회 논문지 Vol.11 No.7
현재 의료분야에서는 방사선 차폐체로서 납(Pb)이 널리 쓰이고 있다. 하지만 납은 무게가 매우 무거워 납 치마 등의 방호복은 장시간 착용이 어려우며, 인체에 치명적인 납 중독의 위험이 상시 가지고 있다는 문제점을 가지고 있다. 이러한 문제점을 해결하고자 납을 대체 할 수 있는 물질에 대한 많은 연구가 진행되고 있다. 현재 납의 대체물질로써 대표적인 바륨(Ba)과 요오드(I) 등은 우수한 차폐능을 가지고 있지만, 30keV 근처의 에너지 영역에서 특성 X선을 방출하는 특성을 가지고 있다. 환자나 방사선 종사자의 경우 차폐체를 인체에 접촉하고 있는 경우가 많으므로 차폐체에서 발생되는 특성 X선이 인체에 직접 조사되어 방사선 피 폭을 증가시킬 위험이 매우 높다. 본 연구에서는 바륨(Ba)과 요오드(I)등에서 발생되는 특성 X선을 제거하기에 적절한 이중구조 차폐체를 방사선 수송코드 중 하나인 FLUKA 수송코드를 개발하여 선행연구로서 진행된 MCNPX 시뮬레이션과 비교 분석하여 이중구조 차폐체의 차폐율에 대한 신뢰성을 검증하고자 하였다. MCNPX와 FLUKA를 이용하여 황산바륨(BaSO4)과 산화비스무스(Bi2O3)로 이루어진 다양한 두께조합의 이중구조 차폐체를 설계하였으며, IEC61331-1에 제시된 모식도를 기하학적으로 동일하게 시뮬레이션 상에 구현하였다. 또한, 120 kVp의 연속 X선 스펙트럼에 대한 차폐체의 투과스펙트럼과 흡수선량을 납과 비교 평가하였다. 평가결과, 0.3mm-BaSO 4 /0.3mm-Bi2O3와 0.1mm-BaSO4 /0.5 mm-Bi2O3 구조에서는 33keV와 37keV의 특성 X선을 모두 흡수하였으며, 90 keV 이상의 고에너지 X선에 대해서도 납과 거의 유사한 차폐효율을 보였다. 또한, FLUKA의 수송코드는 33keV 이하에서는 cut-off 가 발생하여 저에너지 X선 광자에 대한 전산모사에 제약이 있지만, 40keV 이상의 고에너지 영역에서 MCNPX와의 상대오차가 6% 이내로 신뢰성이 매우 우수하다는 것을 확인할 수 있었다. In the current medical field, lead is widely used as a radiation shield. However, the lead weight is very heavy, so wearing protective clothing such as apron is difficult to wear for long periods of time and there is a problem with the danger of lethal toxicity in humans. Recently, many studies have been conducted to develop substitute materials of lead to resolve these problems. As a substitute materials for lead, barium(Ba) and iodine(I) have excellent shielding ability. But, It has characteristics emitting characteristic X-rays from the energy area near 30 keV. For patients or radiation workers, shielding materials is often made into contact with the human body. Therefore, the characteristic X-rays generated by the shielding material are directly exposured in the human body, which increases the risk of increasing radiation absorbed dose. In this study, we have developed the FLUKA transport code, one of the most suitable elements of radiation transport codes, to remove the characteristic X-rays generated by barium or iodine. We have verified the reliability of the shielding fraction of the structure of the structure shielding by comparing with the MCPDX simulations conducted as a prior study. Using the MCNPX and FLUKA, the double layer shielding structures with the various thickness combination consisting of barium sulphate (BaSO 4 ) and bismuth oxide(Bi 2 O 3 ) are designed. The accuracy of the type shown in IEC 61331-1 was geometrically identical to the simulation. In addition, the transmission spectrum and absorbed dose of the shielding material for the successive x-rays of 120 kVp spectra were compared with lead. In results, 0.3 mm-BaSO 4 /0.3 mm-Bi 2 O 3 and 0.1 mm-BaSO 4 /0.5 mm-Bi 2 O 3 structures have been absorbed in both 33 keV and 37 keV characteristic X-rays. In addition, for high-energy X-rays greater than 90 keV, the shielding efficiency was shown close to lead. Also, the transport code of the FLUKA’s photon transport code was showed cut-off on low-energy X-rays(below 33keV) and is limited to computerized X-rays of the low-energy X-rays. But, In high-energy areas above 40 keV, the relative error with MCNPX was found to be highly reliable within 6 %.
The Study on Filling Factor of Radiation Shielding Lead-free Sheet Via Screen Printing Method
Sang-Sik Kang,Ah-Rim Jeong,Su-Min Lee,Seung-Woo Yang,Kyo-Tae Kim,Ye-Ji Heo,Ji-Koon Park 한국방사선학회 2018 한국방사선학회 논문지 Vol.12 No.6
많은 선행 연구에서는 무연 차폐재를 제작하기 위하여 몬테카를로 시뮬레이션을 통해 방사선 차폐 능력과 경량화에 대한 가능성을 제시하고 있다. 하지만, 이는 바인더 및 미세 기공에 대한 구현이 어렵기에 제품화 공정에 필요한 정보를 충분히 제공하지 못하는 실정이다. 이에 본 연구에서는 제품화 공정에 요구되는 겔 페이스트에 대한 정보를 사전에 제공하기 위하여 스크린 프린팅 공법을 활용하여 충전율에 따른 방사선 차폐 능력에 대한 결과를 제시하였다. 본 연구에서는 방사선 차폐 능력을 평가하기 위해 IEC 61331-1: 2014와 KS A 4025에 부합하도록 실험 환경을 설계하였으며, 방사선 조사 조건은 KS A 4021 규격을 준용하여 총 여과 2.0 mmAl로 여과된 100 kVp를 이용하였다. 본 연구 결과, TVL를 기준으로 Pb 1270 μm, BaSO4 3035 μm, Bi2O3 1849 μm, WO3 2631 μm에서 근사한 값으로 분석되었다. 또한, 충전율은 BaSO4 38.6%, Bi2O3 27.1%, WO3 30.15%로 분석되었다. 하지만, 차후 저온고압 성형을 적용한다면 충전율을 높이면서도 기공률을 낮춤으로서 방사선 차폐 능력의 개선이 충분히 가능할 것으로 기대된다. In many previous studies, monte carlo simulation is used to produce lead-free shielding sheet, and the possibility of radiation shielding capability and weight reduction is presented. But it is difficult to simulation for binder and micro-pores because of In fact it does not provide sufficient information necessary for the commercialization process. Therefore, in this paper, the results of radiation shielding capability corresponding to filling factor was presented by using the screen printing method to provide information on gel-paste required for the commercialization process. In this study, the geometric setup for evaluate of radiation shielding ability was designed to comply with IEC 61331-1:2014 and KS A 4025. In addition, radiation irradiation conditions were 100 kVp filtered with 2.0 mmAl total filtration was applied according to KS A 4021 standard. In this study, Pb 1270 ㎛, BaSO4 3035 ㎛, Bi2O3 1849 ㎛ and WO3 2631 ㎛ were analyzed based on ten value layer. Additionally, the filling factor was analyzed as BaSO4 38.6%, Bi2O3 27.1%, WO3 30.15%. However, in the case of applying low-temperature high-pressure molding in the future, it is expected that the radiation shielding capability can be sufficiently improved by reducing the porosity while increasing the filling factor.