• Journal of the Korean Solar Energy Society
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• v.36 no.4
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• pp.1-9
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• 2016

The purpose of this study was to compare heat shading performance of various blind types in summer. 4 types of blinds were employed and the results are summarized as follows: 1) There were significant differences in indoor thermal environment and heat shading performance between different heat shading devices, and functional blinds demonstrated relatively superior heat shading performance. 2) Indoor long wave radiation influx measures were lowest for the coating roll blind (Blind B), followed by the coating venetian blind (Blind C), the venetian blind (Blind A), the roll blind, and not having any blinds at all. 3) Such examination results carry implications to reduce cooling load and enhance the indoor environment.

• Proceedings of the IEEK Conference
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• 1999.11a
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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.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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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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• v.40 no.3
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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.

• Journal of Environmental Science International
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• v.13 no.7
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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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.11a
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• pp.123-127
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• 1992

When MOS devices is exposed to radiation, radiation effects of P-type MOS capacitor can cause modulation and/or degradation in devices characteristics and its operating life. The oxide layer is grown in $O_2$+T.C.E. and its thickness ranges from 40 to 80 nm. Irradiations on MOS capacitor were performed by Cobalt-60 gamma ray source and total dose ranges from $10^4$ to $10^8$ rads. The radiation effect on electrical conduction characteristics(I-V) in MOS capacitor was measured as a function of gate oxide thickness and total dose. From the experimental result, I-V characteristics is found to be influenced strongly by total dose in irradiated p-type MOS capacitors. The ohmic current is dependant on of total dose in irradiated P-type MOS capacitors. This results are explained using surface states at interface radiation-induced traps.

• Proceedings of the Materials Research Society of Korea Conference
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• 1993.11a
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• pp.18-18
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• 1993

• Journal of Korean society of Dental Hygiene
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• v.14 no.4
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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.

• Progress in Medical Physics
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• v.31 no.3
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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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• v.34 no.1
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• pp.31-36
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• 2009

The purpose of this study is to measure the tube voltage, the tube current/volume, exposure time and exposure dose of diagnostic X-ray unit in each doctor offices, hospitals and general hospitals for evaluating the performance of such device, to learn the method and technology of its measurement and to suggest its importance. Research subjects were total 30 X-ray units and divided into groups of 10 X-ray units each. The tube voltage, the tube current/volume, exposure time and exposure dose were measured using percentage average error, and then reproducibility of exposure dose was measured through calculating coefficient of variation. The results are like followings; The tube voltage correctness examination showed that incongruent devices among total 30 X-ray units were 5 devices (16.7%). The tube current correctness examination showed that incongruent X-ray units were 3 devices (10.0%). The tube current volume correctness examination showed that incongruent X-ray units were 4 devices (13.3%). Finally, according to exposure time correctness examination, incongruent X-ray units were 5 devices (16.7%) and according to reproducibility examination of exposure dose, incongruent X-ray units were 7 devices (23.3%). Above results showed serious problem in performance management based on management regulation of diagnostic X-ray unit; it means that regular checkout and safety management are required, and as doing so, patients will be able to receive good quality of medical service by the reduction of radiation exposure time, image quality administration, unnecessary retake and etc. Therefore, this study suggests that the performance of diagnostic X-ray units should be checked regularly.