• Journal of Radiation Protection and Research
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• 제42권3호
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• pp.141-145
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• 2017

Background: The concrete walls inside the vaults of cyclotron facilities are activated by neutrons emitted by the targets during radioisotope production. Reducing the amount of radioactive waste created in such facilities is very important in case they are decommissioned. Thus, we proposed a strategy of reducing the neutron activation of the concrete walls in cyclotrons during operation. Materials and Methods: A polyethylene plate and B-doped Al sheet (30 wt% of B and 2.5 mm in thickness) were placed in front of the wall in the cyclotron room of a radioisotope production facility for pharmaceutical use. The target was Xe gas, and a Cu block was utilized for proton dumping. The irradiation time, proton energy, and beam current were 8 hours, 30 MeV, and $125{\mu}A$, respectively. To determine a suitable thickness for the polyethylene plate set in front of the B-doped Al sheet, the neutron-reducing effects achieved by inserting such sheets at several depths within polyethylene plate stacks were evaluated. The neutron fluence was monitored using an activation detector and 20-g on de Au foil samples with and without 0.5-mm-thick Cd foil. Each Au foil sample was pasted onto the center of a polyethylene plate and B-doped Al sheet, and the absolute activity of one Au foil sample was measured as a standard using a Ge detector. The resulting relative activities were obtained by calculating the ratio of the photostimulated luminescence of each foil sample to that of the standard Au foil. Results and Discussion: When the combination of a 4-cm-thick polyethylene plate and B-doped Al sheet was employed, the thermal neutron rate was reduced by 78%. Conclusion: The combination of a 4-cm-thick polyethylene plate and B-doped Al sheet effectively reduced the neutron activation of the investigated concrete wall.

• KIEAE Journal
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• 제3권3호
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• pp.19-25
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• 2003

The Address No.0 of Eco-friendly Architecture offers unique experience for those who visit the place to envisage the future architecture where nature, human and building exist in harmony. It is open to the general public including the students of elementary and secondary schools. This house has been built to provide opportunities for the general public to experience eco-friendly architecture. It's floor area is 42 pyung($140m^2$) and the overall site has the area of 180 pyung($600m^2$). The following illustrates some of its prominent features : ${\bullet}$ Remodeling of a traditional Korean residence ${\bullet}$ Application of passive solar systems ${\bullet}$ Use of clerestory windows and daylighting systems(washroom and machine room) ${\bullet}$ Operation of solar water heaters with flat plate collectors ${\bullet}$ Construction of Biotop(small ecological world) ${\bullet}$ Water circulation for Biotop by photovoltaic(150W) and wind power(400W) generation ${\bullet}$ Outdoor hot water supplied by all-glass evacuated solar tubes. Through this Address No.0 of Eco-friendly Architeture conclusions are as followings. 1. The array of tubes in collector has the best nice in that the number of tube is nine and the tilt angle is the latitude $+20^{\circ}$. 2. The thermal performance of the all-glass solar vacuum collector was excellent than of the flate-plate solar collector. 3. The adaption of new small wind power systems to buildings were proved to produce a profit if it is considered the expense of environment improvement and the wind speed increasing according to rise of building hight.

• 설비공학논문집
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• 제19권3호
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• pp.269-274
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• 2007

A 3-way valve has been applied to a distributor in a hot-water heating system and the performance of the system was evaluated in view of the variations of pressure drop and flow rate. The 3-way valve has been designed to bypass overplus hot-water when a control valve is closed. Note that the flow goes through heating pipeline in normal operation. In the present study, the measured pressure drops in each part of the flow paths show that the contribution to the total pressure drop is in the order of the supply header with control valves, piping system of each room and return header of the distributor, even though the amount of it is different according to the flow paths. As a result of performance test by sequential closing of the control valves, the variations of pressure drop and flow rate in the distributor with 3-way valves is much lower than those with previous 2-way valves, which prevent noises induced by pressure fluctuations.

• 전자공학회논문지CI
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• 제45권5호
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• pp.74-84
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• 2008

지역적으로 분산되어 있는 지식 노동자들 간에 진보된 협업을 지원하기 위해서, 유비쿼터스 컴퓨팅의 범위 내에서 많은 연구가 진행되어 왔다. 특히 전통적인 회의실 기반의 협업 환경 (편리하지 못한 시청각 자료의 공유, 협업 도구의 어려운 조작 등)에서 이미 알려진 여러 문제점 들을 해결하기 위해, 개념적인 프레임워크들이 설계되었다. 실용적이고 편리한 협업 환경 구성을 위해, 본 논문에서는 에이전트 기반의 서비스 합성 모델을 개념적으로 설계한다. 사용자 입장에서 복잡한 협업 환경의 내부 구조를 알 필요 없이, 상위 수준의 작업 지시를 하면 협업 환경에서 주어진 작업을 수행하기 위한 서비스들을 자동적으로 발견하고, 연결하기 위한 모델을 설계한다. 본 서비스 합성 모델을 기반으로 다중 에이전트 시스템 기반의 다자간 협업 환경관리 툴킷을 개발하여, 직관적인 GUI를 통해 협업 노드 상의 다양한 서비스들을 설정, 운용하는 방법을 제공하고, 주어진 작업을 수행하기 위해 필요한 서비스들을 발견하고 연결하는 기능을 제공한다. 구현된 툴킷의 실용성을 실증하기 위하여, 개발된 툴킷을 기반으로 영상 회의를 위한 기능을 제공하는 협업 서비스들을 구현한다.

• 지역사회간호학회지
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• 제14권3호
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• pp.407-414
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• 2003

Purpose: The purpose of this study was to discern the effects of music therapy on the patients' level of anxiety and operative satisfaction during cataract surgery under local anesthesia. Method: The subjects for this study were fifty patients. Half of the subjects were categorized as an experimental group and the other half as a control group. All of the subjects were admitted to one hospital in Seoul for cataract surgery. This study was conducted from September 7 to October 2, 2002. The level of anxiety determined by self-reporting anxiety, pulse rate, systolic blood pressure, and diastolic blood pressure, was measured before and after the music therapy. The satisfaction degree was measured after the surgery. The tools for this study were Spilberger's state anxiety inventory and Patient Care Management System. Each patient in the experimental group chose the music used in his/her surgery and it was played through an audio system in the operating room. The data analysis was performed using the SAS/pc+(version 8.0). Results: 1. The anxiety of the experimental group decreased significantly compared to the control group. 2. The pulse rate of the experimental group decreased more than the control group. 3. The blood pressure of the experimental group decreased more than the control group. 4. The operative satisfaction of the experimental group was higher than the control group. Conclusion: According to the previous results, music therapy turned out to be a very efficient way to increase the satisfaction of a cataract patient after surgery by reducing the anxiety and the pulse rate of the patient during an operation with local anesthesia.

• 한국가스학회지
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• 제22권1호
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• pp.78-85
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• 2018

본 연구를 통하여 반도체 FPD 제조설비 및 클린룸에 관련한 설비의 위험성분석과 그에 대한 근원적인 안전대책을 연구하고, 설비 및 환경의 특수성을 고려한 방폭 설계 모델링화를 검토하여 관련 설비의 설계 및 제작에 기술적인 기준과 근거로 활용하고자 하며, 아래와 같은 성과로서 향후 반도체 FPD 산업의 기술적 기준 수립 및 관련 산업에 기여할 것으로 생각한다. 1) 관련 국제 기술규격과 법령, 설비의 특성을 반영한 FAB 장비의 최적화된 폭발위험장소의 모델링 도출 2) FAB 장비 및 클린 룸의 특성을 고려한 위험설비의 안전성 확보 (Fool-Proof와 Fail Safe)를 위한 안전시스템 구축방안과 안전기준 및 대책 도출 3) 향후 FAB 장비의 방폭 설계에 대한 가장 효율적인 기준 적용을 통한 신규 FAB 장비의 방폭 성능의 유연성 확보하고 수립된 안전기준을 통한 설비와 안전시스템의 신뢰성 검증 절차 운영을 위한 "안전인증제도"의 자율적 향상화.

• The Korean Journal of Physiology and Pharmacology
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• 제24권5호
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• pp.423-431
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• 2020

This study aimed to evaluate the effect of curcumin on brain hypoxic-ischemic (HI) damage in neonatal rats and whether the phosphoinositide 3-kinase (PI3K)/Akt/vascular endothelial growth factor (VEGF) signaling pathway is involved. Brain HI damage models were established in neonatal rats, which received the following treatments: curcumin by intraperitoneal injection before injury, insulin-like growth factor 1 (IGF-1) by subcutaneous injection after injury, and VEGF by intracerebroventricular injection after injury. This was followed by neurological evaluation, hemodynamic measurements, histopathological assessment, TUNEL assay, flow cytometry, and western blotting to assess the expression of p-PI3K, PI3K, p-Akt, Akt, and VEGF. Compared with rats that underwent sham operation, rats with brain HI damage showed remarkably increased neurological deficits, reduced right blood flow volume, elevated blood viscosity and haematocrit, and aggravated cell damage and apoptosis; these injuries were significantly improved by curcumin pretreatment. Meanwhile, brain HI damage induced the overexpression of p-PI3K, p-Akt, and VEGF, while curcumin pretreatment inhibited the expression of these proteins. In addition, IGF-1 treatment rescued the curcumin-induced down-regulated expression of p-PI3K, p-Akt, and VEGF, and VEGF overexpression counteracted the inhibitory effect of curcumin on brain HI damage. Overall, pretreatment with curcumin protected against brain HI damage by targeting VEGF via the PI3K/Akt signaling pathway in neonatal rats.

• Journal of Astronomy and Space Sciences
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• 제30권4호
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• pp.307-314
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• 2013

Infrared optical systems are operated at low temperature and vacuum (LT-V) condition, whereas the assembly and alignment are performed at room temperature and non-vacuum (RT-NV) condition. The differences in temperature and pressure between assembly/alignment environments and operation environment change the physical characteristics of optical and opto-mechanical parts (e.g., thickness, height, length, curvature, and refractive index), and the resultant optical performance changes accordingly. In this study, using input relay optics (IO), among the components of the Immersion GRating INfrared Spectrograph (IGRINS) which is an infrared spectrograph, a simulation based on the physical information of this optical system and an actual experiment were performed; and optical performances in the RT-NV, RT-V, and LT-V environments were predicted with an accuracy of $0.014{\pm}0.007{\lambda}$ rms WFE, by developing an adaptive fitting line. The developed adaptive fitting line can quantitatively control assembly and alignment processes below ${\lambda}/70$ rms WFE. Therefore, it is expected that the subsequent processes of assembly, alignment, and performance analysis could not be repeated.

• International Journal of Automotive Technology
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• 제6권5호
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• pp.437-444
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• 2005

Unburned hydrocarbon (UBHC) emissions from gasoline engines remain a primary engineering research and development concern due to stricter emission regulations. Gasoline engines produce more UBHC emissions during cold start and warm-up than during any other stage of operation, because of insufficient fuel-air mixing, particularly in view of the additional fuel enrichment used for early starting. Impingement of fuel droplets on the cylinder wall is a major source of UBHC and a concern for oil dilution. This paper describes an experimental study that was carried out to investigate the distribution and 'footprint' of fuel droplets impinging on the cylinder wall during the intake stroke under engine starting conditions. Injectors having different targeting and atomization characteristics were used in a 4-Valve engine with optical access to the intake port and combustion chamber. The spray and targeting performance were characterized using high-speed visualization and Phase Doppler Interferometry techniques. The fuel droplets impinging on the port, cylinder wall and piston top were characterized using a color imaging technique during simulated engine start-up from room temperature. Highly absorbent filter paper was placed around the circumference of the cylinder liner and on the piston top to collect fuel droplets during the intake strokes. A small amount of colored dye, which dissolves completely in gasoline, was used as the tracer. Color density on the paper, which is correlated with the amount of fuel deposited and its distribution on the cylinder wall, was measured using image analysis. The results show that by comparing the locations of the wetted footprints and their color intensities, the influence of fuel injection and engine conditions can be qualitatively and quantitatively examined. Fast FID measurements of UBHC were also performed on the engine for correlation to the mixture formation results.

• 한국안전학회지
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• 제29권1호
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• pp.47-53
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• 2014

The application of advanced Main Control Room(MCR) is accompanied with lots of changes and different forms and features through the virtue of new digital technologies. The characteristics of these digital technologies and devices give many opportunities to the interface management, and can be integrated into a compact single workstation in advanced MCR so that workers can operate the plant with minimum physical burden under any operation conditions. However, these devices may introduce new types of human errors and thus a means to evaluate and prevent such errors is needed, especially those related to characteristics of digital devices. This paper reviewed the new type of human error hazards of tasks based on digital devices and surveyed researches on physiological assessment related to human error. An experiment was performed to verify human error hazards by physiological responses such as EEG which was measured to evaluate the cognitive workload of operators. And also, the performances of four tasks which are representative in human error hazard tasks based on digital devices were compared. Response time, ${\beta}$ power spectrum rate of each task by EEG, and mental workload by NASA-TLX were evaluated. In the results of the experiment, the rate of the ${\beta}$ power was increased in the task 1 and task 4 which are searching and navigating task and memory task of hierarchical information, respectively. In case of the mental workload, in most of evaluation items, task 1 and 4 were highly rated comparatively. In this paper, human error hazards might be identified by highly cognitive workload. Conclusively, it was concluded that the predictive method which is utilized in this paper and an experimental verification can be used to ensure the safety when applying the digital devices in Nuclear Power Plants (NPPs).