• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.4
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• pp.478-483
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• 2014

We propose a new method which can extract the information about the electronic traps in the semi-insulating GaN buffer of AlGaN/GaN heterostructure field-effect transistors (HFETs) using a simple test structure. The proposed method has a merit in the easiness of fabricating the test structure. Moreover, the electric fields inside the test structure are very similar to those inside the actual transistor, so that we can extract the information of bulk traps which directly affect the current collapse behaviors of AlGaN/GaN HEFTs. By applying the proposed method to the GaN buffer structures with various unintentionally doped GaN channel thicknesses, we conclude that the incorporated carbon into the GaN back barrier layer is the dominant origin of the bulk trap which affects the current collapse behaviors of AlGaN/GaN HEFTs.

• Journal of the Korean Society of Safety
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• v.33 no.6
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• pp.85-92
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• 2018

This study aimed to reduce of traps incident of metro train door by suggesting preventive actions throughout analyzing why railway drivers and passengers commit unsafe behaviors which are human factors making occurrence of the incidents. The incident cases were analyzed and Incident Tree was structured by brainstorming with safety experts. In addition, the questionnaire survey was conducted for comparison with the analysis results. As the result, this study suggested driver's factors, passenger's factors, and public relation plan for safe use of metro in order to reduce the frequency of the incidents. For driver's factors, implementing job-rotation systems between railway and non-railway drivers, installing Object Detection Sensors between the metro doors and PSD, and flexible operation of dwell time were suggested. For passenger's factors, placing a platform safety person, installing a safety fence in front of the stairs and the elevators, and country wide public relations through mass media were suggested.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.6
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• pp.412-417
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• 2000

High electric field stressed trap distributions were investigated in the thin silicon oxide of polycrystalline silicon gate metal oxide semiconductor capacitors. The transient currents associated with the off time of stressed voltage were used to measure the density and distribution of high voltage stress induced traps. The transient currents were due to the discharging of traps generated by high stress voltage in the silicon oxides. The trap distributions were relatively uniform near both cathode and anode interface in polycrystalline silicon gate metal oxide semiconductor devices. The stress generated trap distributions were relatively uniform the order of $10^{11}$~$10^{12}$ [states/eV/$\textrm{cm}^2$] after a stress. The trap densities at the oxide silicon interface after high stress voltages were in the $10^{10}$~$10^{13}$ [states/eV/$\textrm{cm}^2$]. It was appeared that the transient current that flowed when the stress voltages were applied to the oxide was caused by carriers tunneling through the silicon oxide by the high voltage stress generated traps.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.5
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• pp.329-337
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• 2001

It has been known that the leakage current in the low field region consists of the dielectric relaxation current and intrinsic leakage current, which cause the charge loss in dynamic random access memory (DRAM) storage capacitor using (Ba,Sr)TiO$_{3}$ (BST) thin film. Especially, the dielectric relaxation current should be seriously considered since its magnitude is much larger than that of the intrinsic leakage current in giga-bit DRAM operation voltage (~IY). In this study, thermally stimulated current (TSC) measurement was at first applied to investigate the activation energy of traps and relative evaluation of the density of traps according to process change. And, through comparing TSC to early methods of I-V or I-t measurement and analyzing, we identify the origin of the dielectric relaxation current and investigate the reliability of TSC measurement. First, the polarization condition such as electric field, time, temperature and heating rate was investigated for reliable TSC measurement. From the TSC measurement, the energy level of traps in the BST thin film has been investigated and evaluated to be 0.20($\pm$0.01) eV and 0.45($\pm$0.02) eV. Based on the TSC measurement results before and after rapid thermal annealing (RTA) process, oxygen vacancy is concluded to be the origin of the traps. TSC characteristics with thermal annealing in the MIM BST capacitor have shown the same trends with the current-voltage (I-V) and current-time (I-t) characteristics. This means that the TSC measurement is one of the effective methods to characterize the traps in the BST thin film.

• The Korean Journal of Petroleum Geology
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• v.9 no.1_2 s.10
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• pp.24-39
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• 2001

Prospecting for energy and mineral resources is essential kind of public fundamentals that manage the nation's economy. Most explorations in the past were concentrated in the simple structural traps in relatively shallow depth. Due to their vast exploitation, recent history has shown that the emphasis in explorations has steadily shifted toward the subtle stratigraphic traps in deeper level. Increasing exploration for the subtle stratigraphic traps in deeper level requires precise correlation and assessment of deeply buried strata in the basin. However, the descriptive stratigraphic principles used for evaluation of the simple structural traps are limited to delineate the subtle stratigraphic traps in deeper depth. As this occurs, it is imperative to establish a new stratigrtaphic paradigm that allows a more sophisticated understanding on the basin stratigraphy. This study provides an exemplary application of integrated stratigraphic approach to defining basin stratigraphy of the Middle Ordovician Taebacksan Basin and the Cretaceous South Yellow Sea Basin, Korea. The integrated stratigraphic approach gives much better insight to unravel the stratigraphic response to tectonic evolution of the basins, which can be utilized for enhancing the efficiency of resources exploration and development in the basins. Thus, the integrated stratigraphic approach should be considered as a new stratigraphic norm that can improve the probability of success in any type of resources exploration and development project.

• Economic and Environmental Geology
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• v.36 no.2
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• pp.59-74
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• 2003

Prospecting for energy and mineral resources is essential kind of public fundamentals that manage the nation's economy. Most explorations in the past were concentrated in the simple structural traps in relatively shallow depth. Due to their vast exploitation, recent history has shown that the emphasis in explorations has steadily shifted toward the subtle stratigraphic traps in deeper level. Increasing exploration for the subtle stratigraphic traps in deeper level requires precise correlation and assessment of deeply buried strata in the basin. However, the descriptive strati-graphic principles used for evaluation of the simple structural traps are limited to delineate the subtle stratigraphic traps in deeper depth. As this occurs. it is imperative to establish a new stratigraphic paradigm that allows a more sophisticated understanding on the basin stratigraphy. This study provides an exemplary application of integrated stratigraphic approach to defining basin history of the Middle Ordovician Taebacksan Basin, Korea. The integrated stratigraphic approach gives much better insight to unravel the stratigraphic response to tectonic evolution of the basins, which can be utilized fer enhancing the efficiency of resources exploration and development in the basins. Thus, the integrated stratigraphic approach should be emphasized as a new stratigraphic norm that can improve the probability of success in any type of resources exploration and development project.

• Korean journal of applied entomology
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• v.45 no.1 s.142
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• pp.25-30
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• 2006

The female sex pheromone of the peach leafminer, Lyonetia clerkella Linne (Lepidoptera: Lyonetiidae), was analyzed by coupled gas chromatographic-electroantennographic detector (GC-EAD). GC-EAD analyses of pheromone gland extract revealed a single compound that elicited responses from male antennae. Retention time on DB-1 column of EAD-active compound was identical to that of synthetic (145)-14-Methyl-1-octadecene (14Sme-1-18Hy). In field tests, sticky traps baited with synthetic 14Sme-1-18Hy alone were highly attractive to male. Traps with 0.1 mg dose showed the lowest catches, but there were no significant difference in the numbers of moth caught in traps baited with doses of 0.5 and 1.0 mg. The results of the field assays for longevity of pheromone traps showed that effectiveness of lures maintained for at least 8 weeks under field condition. The attractiveness of 14Sme-1-18Hy was not affected by the addition of butylated hydroxytoluene (BHT) in lures as an antioxidant. Traps baited with 0.5 mg 14Sme-1-18Hy were successfully used to monitor L. clerkella male flights. Analysis of seasonal trap catches over two years showed that moth flight activity in peach orchards occurred over a period of seven months with six generations in Suwon.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.375-380
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• 2014

The sweetpotato whitefly (SPW), Bemisia tabaci Gennadius, is a major pest in tomato greenhouses on Jeju Island because they transmit viral diseases. To develop practical sampling methods for adult SPWs, yellow-color sticky traps were used in commercial tomato greenhouses throughout the western part of Jeju Island in 2011 and 2012. On the basis of the size and growing conditions in the tomato greenhouses, 20 to 30 traps were installed in each greenhouse for developing a sampling plan. Adult SPWs were more attracted to horizontal traps placed 60 cm above the ground than to vertical trap placed 10 cm above the plant canopy. The spatial patterns of the adult SPWs were evaluated using Taylor's power law (TPL) and Iwao's patchiness regression (IPR). The results showed that adult SPWs were aggregated in each surveyed greenhouse. In this study, TPL showed better performance because of the coefficient of determination ($r^2$). On the basis of the fixed-precision level sampling plan using TPL parameters, more traps were required for higher precision in lower SPW densities per trap. A sequential sampling stop line was constructed using TPL parameters. If the treatment threshold was greater than 10 maximum adult SPWs on a trap, the required traps numbered 15 at a fixed-precision level of 0.25. In estimating the mean density per trap, the proportion of traps with two or more adult SPWs was more efficient than whole counting: ${\ln}(m)=1.19+0.90{\ln}(-{\ln}(1-p_T))$. The results of this study could be used to prevent the dissemination of SPW as a viral disease vector by using accurate control decision in SPW management programs.

• Korean journal of applied entomology
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• v.59 no.4
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• pp.295-301
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• 2020

In this study, we aimed to investigate the changes in the catch rate of Monochamus saltuarius, based on sexual maturation by using aggregation-sex pheromone traps. Ovariole development of caught M. saltuarius females was compared to that of the ones not caught using traps. In a mesh cage set up at the Hongneung experimental forest, we placed a multi-funnel trap with or without an aggregation-sex pheromone lure. M. saltuarius adults, which emerged from pine logs, were grouped in four according to the emergence dates (0, 1, 7, and 10 days after emergence [DAE]). We released beetles into the mesh cage to investigate the catch rate using the traps. In each group, a total of 80 beetles (20 beetles × 4 replications) were tested, making it a total of 320 beetles. Among the four groups, M. saltuarius adults in the 7 DAE group were caught more frequently using the traps, especially with a pheromone lure; the other groups showed a low catch rate. A similar number of female and male beetles were caught using the traps. Regarding ovariole development, all the female adults in the 0 and 1 DAE groups were immature, while those in the other two groups were completely developed. Therefore, aggregation-sex pheromone traps might have a limitation in the prevention of pine wilt disease because of the transmission of pine wood nematode during maturation feeding of newly emerged M. saltuarius adults. However, aggregation-sex pheromone traps can be effective for collecting sexually mature M. saltuarius adults, for the investigation of seasonal occurrence of beetles in forests.

• Journal of the Korean Graphic Arts Communication Society
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• v.15 no.1
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• pp.1-15
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• 1997