이온전리함 기반의 컨테이너 검색용 고에너지 X-선 선량 측정장치 개발

이정희,임창휘,박종원,이상헌,Lee, Junghee,Lim, Chang Hwy,Park, Jong-Won,Lee, Sang Heon 한국정보통신학회 2020 한국정보통신학회논문지 Vol.24 No.12

X-ray of up to 9MeV are used for container inspection. X-ray intensity must be maintained stably regardless of changes in time. If dose is not constant, it may affect the image quality, and as a result, may affect the inspection of abnormal cargo. Therefore, to acquire high-quality images, continuous dose monitoring is required. In this study, the ion-chamber based device was developed for monitoring the dose change in high-energy x-ray. And to estimate the performance of signal-processing device change according to the environmental change, the output changing due to the change of temperature and humidity was observed. In addition, verification of the device was performed by measuring the output change. As a result of the measurement, there was no significant difference in performance due to changes in temperature and humidity, and the change in output according to the change in exposure was linear. Therefore, it was found that the developed device is suitable for the dose monitoring of high-energy x-ray. 일반적으로 컨테이너 내부검사를 위해서는 최대 9MeV의 X-선을 사용한다. 이때 사용되는 X-선은 선형가속기를 통해 생성되며 일정한 세기의 X-선량이 시간의 변화에 관계없이 안정적으로 유지되어야 한다. 만약 발생되는 X-선의 세기가 일정하지 않다면 영상의 해상도와 대비도 등에 영향을 미칠 수 있으며 결과적으로 컨테이너 내부의 이상화물에 대한 검사에 영향을 미칠 수 있다. 그러므로 고화질의 영상을 획득하기 위해서는 발생되는 X-선 선량에 대한 지속적인 모니터링이 요구된다. 이와같은 선량 모니터링을 위하여, 본 연구에서는 고에너지 X-선 선량의 변화 측정을 위한 이온전리함 기반의 선량변화 측정장치를 개발하였고 환경변화에 따른 신호처리부의 성능변화를 확인하기 위하여 온도와 습도 변화에 의한 측정값의 변화를 관찰하였다. 또한, 고에너지 X-선 발생장치에서 발생되는 선량의 변화에 따른 응답특성변화를 측정함으로써 개발한 X-선 선량측정장치의 검증을 수행하였다. 측정결과 온도와 습도의 변화에 따른 성능의 차이가 크게 나타나지 않았으며 입사되는 선량의 변화에 따른 출력의 변화가 선형적이었다. 그러므로 개발한 이온전리함 기반의 선량변화측정장치는 고에너지 X-선의 선량변화의 측정에 적용하기에 적합함을 알 수 있었다.

단감의 저온저장 기간에 따른 해충의 밀도변화에 관한 연구

강창헌,박정규 경상대학교 농업생명과학연구원 2002 농업생명과학연구 Vol.36 No.1

우리나라의 단감의 수출선을 다변화하기 위해서는 검역문제를 해결하여야 한다. 본 논문에서는 저온저장 기간 중에 단감에 존재하는 해충이 저온에 의해서 어느 정도 제거되는지를 조사하였다. 톡톡이류는 약 20일간의 저온(-1±0.5℃)저장에 의해서 밀도가 1/10로 감소하였고, 저장 56일 이후에는 저장 중인 과일에 톡톡이를 찾을 수 없었다. 균식성응애도 저온에 대한 내성이 낮아 저온저장에 의해서 밀도가 현저히 감소하였으며 74일 저장 후에는 거의 찾아볼 수가 없었다. 차응애도 저장 56일 이후에는 전혀 찾아볼 수 없었다. 한편 주머니깍지벌레는 꽃받침 밑에서만 월동 난 상태로 휴면하고 있었는데, 다른 곤충과는 달리 저온에 대한 내성이 강하였다. 저장 74일 이후에도 과일당 5개의 알 수준으로서 다른 충에 비해서 밀도 감소가 뚜렷하지 않았다. 월동난 존재과율도 전 저장기간에 걸쳐 5~13%에 달하였다. 따라서 주머니깍지벌레가 발생하는 포장에서 생산되는 단감의 경우에는 이들을 제거할 수 있는 새로운 기술을 개발해야 할 것이다. Insects or mites on the exporting fruits should not be allowed to meet the quarantine requirements of importing countries. Some fruits are stored before shipment for export at -1±0.5℃. Density changes of the pests on persimmon were checked during the low temperature storage (LTS). The collembolan could be killed by LTS. Density of collembolan under calyx decreased to one-tenth of the initial after a 20-d storage. No collembolan survived after 56-d storage. The LTS resulted in high mortality of the fungus-feeding mite and leaf mite. There were no fungus-feeding and leaf mites on the fruits after a 74- and a 56-d storage, respectively. However the overwintering eggs of grape-myrtle scale (Eriococcus largerstroemiae Kuwana) survived the LTS. Some of them were still alive after a 74-d storage; 5-13% of the sample fruits had the eggs under their calyxes. Therefore the fruits from the orchards infested by E. lagerstroemiae should be treated differently to kill the scales.

TIME/FREQUENCY ANALYSIS OF TERRESTRIAL IMPACT CRATER RECORDS

Chang Heon-Young The Korean Space Science Society 2006 Journal of Astronomy and Space Sciences Vol.23 No.3

The terrestrial impact cratering record recently has been examined in the time domain by Chang & Moon (2005). It was found that the ${\sim}26$ Myr periodicity in the impact cratering rate exists over the last ${\sim}250$ Myrs. Such a periodicity can be found regardless of the lower limit of the diameter up to D ${\sim}35km$. It immediately called pros and cons. The aim of this paper is two-fold: (1) to test if reported periodicities can be obtained with an independent method, (2) to see, as attempted earlier, if the phase is modulated. To achieve these goals we employ the time/frequency analysis and for the first time apply this method to the terrestrial impact cratering records. We have confirmed that without exceptions noticeable peaks appear around ${\sim}25$ Myr, corresponding to a frequency of ${\sim}0.04(Myr)^{-1}$. We also find periodicities in the data base including small impact craters, which are longer. Though the time/frequency analysis allows us to observe directly phase variations, we cannot find any indications of such changes. Instead, modes display slow variations of power in time. The time/frequency analysis shows a nonstationary behavior of the modes. The power can grow from just above the noise level and then decrease back to its initial level in a time of order of 10 Myrs.

基準의 變更에 따른 新値數 및 公差計算 : 對話形式의 컴퓨터 프로그램개발 Development of Interactive Computer Program

玄昌憲,金聖準 江原大學校 産業技術硏究所 1985 産業技術硏究 Vol.5 No.-

In case that the datums chosen for dimension on engineering drawings are unsuitable for manufacturing and inspecting and inspection purposes and it is necessary to redimension the design from new datum. L.E.Farmer presented a theory for performing this change of datum, discussed a procedure for allocating tolerances to new dimensions and presented the procedure of change of datum as part of a computer aided design system. This paper deals with the development of the interactive computer program which is insufficiently presented without all coding list of program by L.E.Farmer.

Structural Alterations in the Gill of the Red Sea Bream, Pagrus major, Exposed to the Harmful Dinoflagellate Cochlodinium polykrikoides

Kim, Chang Sook,Jee, Bo-Young,Bae, Heon Meen 한국수산학회 2002 Fisheries and Aquatic Sciences Vol.5 No.1

The effects of Cochlodinium polykrikoides on the gill of red sea bream, Pagrus major, were examined to clarify the ichthyotoxic mechanisms of this plankton species. The gill of fish exposed to dense blooms over 3,000 cells/mL for 24 h showed severe epithelial separation: a severe edema was found in the secondary lamellar epithelium and interlamellar regions of primary filament. In addition, lipid peroxidation of gill tissue in Chchlodinium-exposed fish was about 2.5 times higher than that of control. The composition of glycoproteins in the gill mucus of Cochlodinium-exposed fish was also changed. These results suggest that the loss of structural integrity of cell membrances in fish gill may be deeply involved in fish death by C. polykrikoides.

지피상태에 (地被狀態) 따른 임지의 (林地) 수저유 (水貯留) 특성

이헌호(Heon Ho Lee),이창우(Chang Woo Lee) 한국산림과학회 1994 한국산림과학회지 Vol.83 No.3

This study was carried out to investigate the water storage charateristics of surface soil by different forest floor conditions and to measure water storage capacity of forest Land at the Yeungnam University forest in Yongjang-ri, Nenam-myoen, Kyongju-gun, Kyongsangbuk-do. The study was conducted for 4 months, from June to September, 1993. The results were summarized as follows ; 1. Infiltration capacity of surface soil for each. forest floor condition was in the order : Oak forest$gt;Oak forest removed Ao layer$gt;Pine forest removed Ao layer$gt;Pine forest$gt;Bare land$gt;Grasses. 2. The absolute values of infiltration capacity were increased as the rain intensity increased, while the order of infiltration capacity for each floor condition was not changed. 3. Infiltration capacity was highly correlated with surface soil hardness and todal pores. 4. Infiltration formula based on the Horton`s could be estimated at each forest floor condition. 5. The model for water storage capacity of forest land expressed by infiltration capacity was estimated using total pores and soil hardness. This study indicates water storage capacity of different forest floor conditions depends on infiltration capacity. Using these formula, it was possible to calculate and estimate water storage capacity of forest land. Therefore, the result of this study will be helpful to increase water storage capacity of forest land and to manage water resources effectively.

Nondimensional modelling of 2D beam for slope discontinuity problem in ANCF

Ji-Heon Kang,이재욱,Jinseok Jang,Chang Young Choi,김건우 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.9

Various mechanical and structural systems possess slope discontinuity. Some bodies with slope discontinuity can be modeled using absolute nodal coordinate formulation, which can accurately express the rigid body mode when using the element and global shape functions. However, at the intersection of slope discontinuities, it is not easy to construct the equation of motion because the orientation changes. The problem of modeling at the intersection can be solved by defining the global slope vector in the body coordinate system instead of the element coordinate system. The analysis time in absolute nodal coordinate formulation is mostly greater than that in floating frame of reference formulation owing to the highly non-linear stiffness matrix. In this study, based on the work of Shabana and Mikkola, the analysis efficiency was demonstrated using the nondimensional model for the slope discontinuity problem in the absolute node coordinate system.

초자체흡인술이 폐쇄우각 녹내장의 전방깊이에 미치는 영향

안병헌,김창식,김용백 충남대학교 의과대학 지역사회의학연구소 1988 충남의대잡지 Vol.15 No.2

From an eye with chronic angle-closure glaucoma, 0.4 ml of vitreous was aspirated at the same time of trabeculectomy. The ultrasonographic measurement revealed decrease in the length of the vitreous cavity and increase in the depth of the anterior chamber by 0.3 mm at 2 months following the vitreous tap when compared with the preoperative measurement. The other 4 eyes which had undergone argon laser iridectomy or trabeculectomy alone did not show change in the intraocular intersegmental distances. In certain cases with chronic angle-closure glaucoma, it seemed that the vitreous tap procedure might deepen the anterior chamber following a filtration surgery and give a beneficial effect to prevent a further postoperative synechial closure of the chamber angle.

특허 분석을 통한 건설 기술 연구 기획

김창윤(Kim Chang-Yoon),김형관(Kim Hyoung-Kwan),김창완(Kim Chang-Wan),한승헌(Han Seung-Heon),김문겸(Kim Moon-Kyum) 대한건축학회 2008 大韓建築學會論文集 : 構造系 Vol.24 No.12

Diverse research efforts that have been conducted are reflected in the patent information. Patent analysis facilitates the understanding of the major technological area and how the technologies change. It provides the essential data for strategy development of research and development. In this paper, based on literature analysis and expert review, 40 keywords had been selected for searching advanced construction patents. 737 patents of US, EU, and Japan during January 1991 and May 2006 are analyzed. Technology trends of each phase of construction lifecycle are derived through the patent data and patent map analysis. Construction research and development strategies are deduced based on the patent analysis. This research effort suggests a systematic methodology for how patent information is incorporated into new construction research and development plans.

국내 주거건물 에너지절감 장애요인에 대한 분석

정창헌(Cheong Chang-Heon),김태연(Kim Tae-Yeon),이승복(Leigh Seung-Bok) 대한건축학회 2010 대한건축학회논문집 Vol.26 No.7

Residential building energy consumption is a very important issue to enhance the holistic energy efficiency in Korea. Reasonable energy conservation in residential buildings can be achieved by enhancing building energy efficiency, market transformation, education and policy change. However abrupt change in a nation can cause side-effects. In this study, the barriers which hamper the energy conservation in Korea were investigated through the analysis over the literature, previous study and statistical data. Diverse barriers were derived through this study and the results are categorized to three major classes : technical barriers, socialㆍeconomical barriers and political barriers. Not-sufficient low-energy product, less experienced engineer and the ambiguousness of the embodied energy were the major technical barriers. The previous studies and statistical data indicates the relationship between individual wealth and energy consumption. Furthermore, Rebound effects, lessened attraction of the residential business model and un-organized policy were the social?.economic and political barriers.