• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.330-333
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• 1999

A Schottky characteristic is one of the important properties to determine the performance of GaN electronic devices. In this paper, we have studied how to improve the property after n$^{+}$ layer etching by ICP(Induced Coupled Plasma)-RIE(Reactive ion Etching). We have tried $N_2$radiation, annealing after $N_2$radiation, and annealing in $N_2$environment. We have found that a simple annealing method in $N_2$environment is enough to improve the Schottky characteristic for electronic device-Quality application.n.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.114.2-114.2
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• 2014

The orientation of the constituent molecules in organic thin film devices can affect significantly their performance due to the highly anisotropic nature of ${\pi}$-conjugated molecules. We report here an angle dependent x-ray absorption study of the control of such molecular orientation using well-ordered interlayers for the case of a bilayer heterojunction of chloroaluminum phthalocyanine (ClAlPc) and C60. Furthermore, the orientation-dependent energy level alignment of the same bilayer heterojunction has been measured in detail using synchrotron radiation-excited photoelectron spectroscopy. Regardless of the orientation of the organic interlayer, we find that the subsequent ClAlPc tilt angle improves the ${\pi}-{\pi}$ interaction at the interface, thus leading to an improved short-circuit current in photovoltaic devices based on ClAlPc/C60. The use of the interlayers does not change the effective band gap at the ClAlPc/C60 heterointerface, resulting in no change in open-circuit voltage.

• Journal of Biosystems Engineering
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• 제40권3호
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• pp.186-192
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• 2015

Background: Various solar energy collecting systems have been developed and analyzed for agricultural applications. They include solar thermal and electric devices such as solar crop dryers, solar water pumps, solar greenhouse heating, ventilation for livestock, solar aeration pumps, solar electricity, and many more. Purpose: This review provides the current status of research and development in the field as well as the solar energy systems that are currently in use in the agriculture sector across the globe. Review: Solar energy is the largest and cheapest energy resource on earth; one hour of solar radiation exceeds the complete global energy consumption in one year. The potential annual total solar radiation in South Korea is $3.58-5.4 kWh/m^2/day$. The available solar energy is sufficient for agricultural applications across the entire country. Conclusion: The scope of solar energy utilization in agricultural machinery engineering in South Korea and in other countries is promising.

• 한국환경과학회지
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• 제13권7호
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• pp.681-687
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• 2004

This study was focused on the manufacturing method of a dewatering aid, which would reduce the water content of the sludge cake by enhancing the dewaterability of sewage sludge. The pretreatment technology for sludge by using radiation and among diverse discarded resources were starfish selected as the material to manufacture the dewatering aid. Starfish went through the process of washing, drying, and pulverizing. The starfish powder made in this process was applied to the digested sludge generated at the sewage treatment plant of D City, and its effects were investigated. The starfish powder that was 300 ${\mu}m$ in particle size was added to the irradiated digested sludge. After the application of the condensation process, the sludge with the starfish powder added was dewatered using the belt press and centrifuge, which were the traditional pressure dewatering devices. As the result, it reduced the water content of the sludge 20% higher than the dewatered cake with no dewatering aid added and irradiation. When the powder was added, it contributed to less use of the coagulant added. The more irradiation dose, the lower water content did the dewatered cake have and the more coagulant was needed for condensation, which seems to be a disadvantage that can be compensated for by the starfish dewatering aid. A small-scaled treatment of the study to a radiation technology and dewatering aid using a discarded resource confirmed the potential of dewaterability. Based on the results saying that the dewatering aid and radiation technology can improve dewatering effects using the traditional dewatering devices, this pretreatment technology will be expected to be applied to sewage treatment plants.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1992년도 추계학술대회 논문집
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• pp.123-127
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• 1992

MOS 커패시터가 이온화 방사선에 노출되었을 경우, MOS 커패시터의 방사선 조사 효과는 소자의 전기적 특성 및 동작 수명에 심각한 영향을 일으킬 수 있다. MOS 커패시터는 (100) 방향의 P-type Si wafer 위에 산화막층을 $O^2$+T.C.E. 분위기에서 성장하였으며, 그 두께는 40~80 nm로 만들었다. MOS 커패시터에 대한 방사선 조사는 $Co^{60}-{\gamma}$선을 사용하였고, 조사선량은 $10^4{\sim}10^8$으로 조사하였다. MOS 커패시터에서 전기적 전도 특성의 방사선 조사효과는 산화막 두께와 조사선량을 변화하면서 측정된 P-type MOS 커패시터는 조사선량에 의해서 강하게 영향을 받는다는 것과 저전계 영역에서의 Ohmic 전류가 전체 선량에 의존한다는 것을 알았다. 이 결과는 방사선 조사에 의해 산화막 트랩전하와 산화막-반도체($SiO_2$-Si)계면 트랩전하에 의해서 설명 할 수 있다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1993년도 추계 학술발표 강연 및 논문 개요집
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• pp.18-18
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• 1993

• 한국치위생학회지
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• 제14권4호
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• pp.527-537
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• 2014

Objectives : The purpose of this study was to investigate the influence of the awareness towards dental radiation exposure and concern in the adults. Methods : A self-reported questionnaires was filled out by 470 adults over 19 years old in Seoul from May 16 to July 10, 2013. Results : Fear for dental radiography showed that those who positively thought of radiography had 2.86 folds necessity of radiography than those who did not. Positive responders worried about the hazards of dental radiation 4.64 folds than the negative responders. More worried responders had felt the radiation hazards 1.83 folds than those who worried less. The worried responders also had higher awareness of dental radiation hazards. Conclusions : Frequent use of dental radiography is able to be prevented by protective devices. So it is important to prevent the possible hazards of the dental radiography by personal protective education.

• 한국의학물리학회지:의학물리
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• 제31권3호
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• pp.124-134
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• 2020

Here we review the evolutionary history of radiation therapy technology through the festschrift of articles in celebration of the 30th anniversary of Korean Society of Medical Physics (KSMP). Radiation therapy technology used in clinical practice has evolved over a long period of time. Various areas of science, such as medical physics, mechanical engineering, and computer engineering, have contributed to the continual development of new devices and techniques. The scope of this review was restricted to two areas; i.e., output energy production and functional development, because it is not possible to include all development processes of this technology due to space limitations. The former includes the technological transition process from the initial technique applied to the first model to the latest technique currently used in a variety of machines. The latter has had a direct effect on treatment outcomes and safety, which changed the paradigm of radiation therapy, leading to new guidelines on dose prescriptions, innovation of dose verification tools, new measurement methods and calculation systems for radiation doses, changes in the criteria for errors, and medical law changes in all countries. Various complex developments are covered in this review. To the best of our knowledge, there have been few reviews on this topic and we consider it very meaningful to provide a review in the festschrift in celebration of the 30th anniversary of the KSMP.

• Journal of Radiation Protection and Research
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• 제34권1호
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• pp.31-36
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• 2009

일부지역의 병원에 설치, 운영되고 있는 진단용 X선 발생장치틀 의원, 병원, 종합병원별로 관 전압, 관 전류/량, 조사기간, 조사선량 성능을 평가하여 측정방법과 기술을 배우고 중요성을 알리고자 한다. 진단용 X선발생장치를 그룹별로 10대씩 총 30대에 대하여 관전류/량, 조사시간측정기를 사용하여, 백분율평균오차로 평가하였고 그에 따른 조사선량의 재현성은 변동계수를 계산하여 평가하였다. 진단용 X선 발생장치 30대 중 부적합한 장치는 관전압정확도 시험에서 5대(16.7%), 관전류정확도시험에서 3대(10,0%), 관전류량정확도 시험에서는 4대(13.3%), 조사시간정확도 시험에서는 5대(16.7%), 조사선량의 재현성 시험에서는 7대(23.3%)로 조사되었다. 진단용 X선 발생장치를 관리규정에 의거하여 성능검사 결과에 의해 성능관리의 심각성을 알 수 있었고, 이에 주기적으로 실시하여야 함은 물론 안전하게 관리함으로써 환자 및 방사선관계종사자에 대하여 방사선으로 인한 방사선 피폭경감, 화질영상관리, 재촬영 감소 둥에 의해 환자에게 양질의 의료서비스를 제공하게 될 것이다. 따라서 정기적인 성능검사가 필요하다고 사료된다.

• 한국산학기술학회논문지
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• 제22권2호
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• pp.418-426
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• 2021

이 연구는 방사선 발생장치 제조업체 종사자와 의료기관 종사자들 간의 방사선안전관리에 대한 인식을 알아보고 적극적인 대처능력과 안전수준을 향상시키는데 기초자료로 활용하기 위하여 연구조사하게 되었다. 방사선에 대한 지식, 태도 실천 점수는 성별, 연령, 결혼상태, 직종, 직위, 현 직장근무기간, 직장 총 근무기간, 방사선 관련 유사업무 유무, 매뉴얼 비치 여부, 방어 시설유지 여부, 방어 장비보유 수, 방사선 안전교육 여부, 특수건강검진 여부, 방사선 용어인지 여부와 관련이 있었으며, 특히 방사선 관련 직종에서 방사선사의 지식 점수가 가장 높았다(p<0.05). 방사선 안전관리는 방사선제조업체 종사자 및 의료기관 종사자 모두 방사선 노출에 적극적인 방어 노력이 필요하며방사선 안전관리를 위해서는 지침 준수, 주기적인 교육, 시설보강, 매뉴얼 작성, 특수 건강검진 등 제도적 장치가 필요하다.