• Korean journal of communication and information
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• v.43
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• pp.173-208
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• 2008

This study analyses the business performance according to the business diversification of Korean mass media enterprises from year 2003 to 2006. The conclusions drawn which could be divided into five main parts are the followings: First, newspaper companies pursue unrelated diversification in various industrial areas, in order to gain maximum profit while broadcasting companies exert themselves to provide better service by diversifying the major contents. Second, overall the interviewed companies display a constant decline in profit gained from their major business area thus establishing strategies to broaden their focus on diversification of any sort. Third, the researcher completed group analysis in regard of diversification measure resulting in division of three groups. The group which had the most immense diversification range gained the highest ROE, the lowest ROE volatility, and lesser probability of risk taking. The analysis adresses the companies broadening their business areas by researching and focusing on diversification are relatively stable in terms of the profit they gain. Fourth, the middle level group in terms of sales scale, debts, enterprise history, major share rate and high ROE group carry out diversification progressively. The sales scale affects positively to diversification, while the major share rate affects negatively to diversification. Fifth, in accordance to the research, diversification overall contributes to obtainance of successful outcome. Since there was not an immense amount of studies to be referred in the media area, the researcher interviewed and did panel discussion with numerous strategists and managers who are in charge of diversification of media companies. However, collection of only 4 years of data limits the research to be considered to be a generalized study, and does not reflect time gap between business diversification and business performance. Development is required in future studies to be established regarding the media companies' specificity different to other industries, classified the media companies into media types, and consider the time gap in the diversification activities and business performance.

• Korean journal of applied entomology
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• v.54 no.1
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• pp.7-15
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• 2015

CpBV (Cotesia plutellae bracovirus) is a polydnavirus and encodes a cystatin (CpBV-CST1) gene. Its overexpression suppresses insect immunity and alters insect developmental processes. This study aimed to construct a genetically modified (GM) tobacco to further explore the physiological function of the viral cystatin and to apply to control insect pests. To this end, the transgenic tobacco lines were screened in expression of the target gene and assessed in insecticidal activity. A recombinant vector (pBI121-CST) was prepared and used to transform a bacterium, Agrobacterium tumefasciens. The transformed bacteria were used to generate transgenic tobacco lines, which were induced to grow callus and resulted in about 92% of shoot regeneration. The regenerated plants were screened by PCR analysis to confirm the insertion of the target gene in the plant genome. In addition, the expression of the target gene was assessed in the regenerated plants by quantitative real-time PCR (qRT-PCR). The qRT-PCR analysis showed that the transgenic line plant expressed the target gene about 17 times more than the control tobacco, indicating a stable insertion and expression of the target gene in the transgenic tobacco line. The insecticidal activity was then analyzed using the screened transgenic tobacco lines against the teneral 1st instar larvae of the oriental tobacco budworm, Helicoverpa assulta. Though there was a variation in the insecticidal efficacy among transgenic lines, T9 and T12 lines exhibited more than 95% mortality at 7 days after feeding treatment. These results suggest that CpBV-CST1 is a useful genetic resource to be used to generate GM crop against insect pests.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.119-129
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• 2004

This paper is designed to report the results of development and validation procedures in relation to the Freeway Incident Management System (FIMS) prototype development as part of Intelligent Transportation Systems Research and Development program. The central core of the FIMS is an integration of the component parts and the modular, but the integrated system for freeway management. The whole approach has been component-orientated, with a secondary emphasis being placed on the traffic characteristics at the sites. The first action taken during the development process was the selection of the required data for each components within the existing infrastructure of Korean freeway system. After through review and analysis of vehicle detection data, the pilot site led to the utilization of different technologies in relation to the specific needs and character of the implementation. This meant that the existing system was tested in a different configuration at different sections of freeway, thereby increasing the validity and scope of the overall findings. The incident detection module has been performed according to predefined system validation specifications. The system validation specifications have identified two component data collection and analysis patterns which were outlined in the validation specifications; the on-line and off-line testing procedural frameworks. The off-line testing was achieved using asynchronous analysis, commonly in conjunction with simulation of device input data to take full advantage of the opportunity to test and calibrate the incident detection algorithms focused on APID, DES, DELOS and McMaster. The simulation was done with the use of synchronous analysis, thereby providing a means for testing the incident detection module.

• Korean Journal of Ecology and Environment
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• v.46 no.3
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• pp.332-342
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• 2013

We collected zooplankton from May to October, 2011, with the aim of understanding the zooplankton community distribution and food web interaction between the open water and littoral (aquatic plants) zones in two small reservoirs with different land covers (Sobudang, Myeongdong). Small-sized reservoirs are more abundant in South Korea, and a total of 51 and 65 species of zooplankton were identified at the two small reservoir (Sobudang and Myeongdong), where zooplankton densities were more abundant in the littoral zone than in the open water zone. Cladocerans and copepods densities were also higher in the littoral zone, in contrast, rotifers showed higher densities in the open water zone (t-test, P/0.05). Epiphytic zooplankton dominated at the littoral zone (Lecane, Monostyla, Alona and Chydorus) because aquatic plants provided refuge spaces for attachment. Some rotifers (e.g. Brachionus, Keratella and Polyarthra) were more abundant in the open water zone because of their small size, which might help them to go unnoticed by predators. In two-way ANOVA, rotifers related to two reservoirs or habitat space (littoral zone and open water zone), but cladocerans and copepods showed a statistically significant relationship on only two reservoirs. The results of stable isotope analysis showed that zooplankton in the littoral zone tended to depend on organic matter attached to aquatic plants as a food source, which indicates the avoidance of competition of zooplankton with other macro-invertebrates (e.g. Damselfly larva, Cybister brevis and Neocardina denticulate). As a result, zooplankton community distribution is determined by not only habitat space (aquatic plant zone and open water zone) but also by food source (phytoplankton).

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.2
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• pp.132-139
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• 2017

This study was conducted to find out the effects of over seeding using new grass varieties orchardgrass 'Kordione' and 'Onnuri', and tall fescue 'Greenmaster' on botanical composition and dry matter productivity from 2013 to 2016 in low productivity hilly pasture, middle area of Korea. There were used 3 grass seed mixture types made of different compositions and amounts {T1: control - no over seeding, T2: tall fescue (TF) 'Greenmaster' $18kg\;ha^{-1}$, orchardgrass (OG) 'Kordione' $9kg\;ha^{-1}$, Perennial ryegrass (PRG) 'Linn' $5kg\;ha^{-1}$, and Kentucky bluegrass (KBG) 'Kenblue' $2kg\;ha^{-1}$, T3: TF 'Greenmaster' $9kg\;ha^{-1}$, OG 'Kordione' $18kg\;ha^{-1}$, PRG 'Linn' $5kg\;ha^{-1}$, and KBG ' Kenblue' $2kg\;ha^{-1}$, T4: TF 'Greenmaster' $9kg\;ha^{-1}$, OG 'Onnuri' $18kg\;ha^{-1}$, PRG 'Linn' $5kg\;ha^{-1}$, and KBG 'Kenblue' $2kg\;ha^{-1}$}. In the botanical composition of grassland, T1 nearly remained constant in other seasons while ratio of weeds were increased in summer season. T2 was better than control (T1) in portion of grass ratio, which has increased by 80%. In the early time of establishment, the portions of OG were increased in T2, but TF rate was increased after 3 years later when grass was established. T3 and T4 showed a very similar patterns, grass ratio had increased by 80% and the portion of KBG had increased as time passed. T2 ($129,763kg\;ha^{-1}$) was showed the highest dry matter yield than other treatments (T1: $6,756kg\;ha^{-1}$, T3: 9641, and T4: 10,738) in 2016.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.45-47
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• 2002

반도체 소자의 고집적화 및 고속화가 요구됨에 따라 MOSFET 구조의 게이트 절연막으로 사용되고 있는 SiO₂ 박막의 두께를 감소시키려는 노력이 이루어지고 있다. 0.1㎛ 이하의 소자를 위해서는 15Å 이하의 두께를 갖는 SiO₂가 요구된다. 하지만 두께감소는 절연체의 두께와 지수적인 관계가 있는 누설전류를 증가시킨다[1-3]. 따라서 같은 게이트 개패시턴스를 유지하면서 누설전류를 감소시키기 위해서는 높은 유전상수를 갖는 두꺼운 박막이 요구되는 것이다. 그러므로 약 25정도의 높은 유전상수를 갖고 5.2～7.8 eV 정도의 비교적 높은 bandgap을 갖으며, 실리콘과 열역학적으로 안정한 물질로 알려진 HfO2[4-5]가 최근 큰 관심을 끌고 있다. 본 연구에서는 HfO₂ 박막을 실제 소자에 적용하기 위하여 전극 및 열처리에 따른 HfO₂ 박막의 미세구조 및 전기적 특성에 관한 연구를 수행하였다. 이를 위해, HfO₂ 박막을 reactive DC magnetron sputtering 방법으로 증착하고, XRD, TEM, XPS를 사용하여 ZrO₂ 박막의 미세구조를 관찰하였으며, MOS 캐패시터 구조의 C-V 및 I-V 특성을 측정하여 HfO₂ 박막의 전기적 특성을 관찰하였다. HfO₂ 타겟을 스퍼터링하면 Ar 스퍼터링에 의해 에너지를 가진 산소가 기판에 스퍼터링되어 Si 기판과 반응하기 때문에 HfO₂ 박막 형성과 더불어 Si 기판이 산화된다[6]. 그래서 HfO₂같은 금속 산화물 타겟 대신에 순수 금속인 Hf 타겟을 사용하고 반응성 기체로 O₂를 유입시켜 타겟이나 시편위에서 high-k 산화물을 만들면 SiO/sub X/ 계면층을 제어할 수 있다. 이때 저유전율을 갖는 계면층은 증착과 열처리 과정에서 형성되고 특히 500℃ 이상에서 high-k/Si를 열처리하면 계면 SiO₂층은 증가하는 데, 이것은 산소가 HfO₂의 high-k 박막층을 뚫고 확산하여 Si 기판을 급속히 산화시키기 때문이다. 본 방법은 증착에 앞서 Si 표면을 희석된 HF를 이용해 자연 산화막과 오염원을 제거한 후 Hf 금속층과 HfO₂ 박막을 직류 스퍼터링으로 증착하였다. 우선 Hf 긍속층이 Ar 가스 만의 분위기에서 증착되고 난 후 공기중에 노출되지 않고 연속으로 Ar/O₂ 가스 혼합 분위기에서 반응 스퍼터링 방법으로 HfO₂를 형성하였다. 일반적으로 Si 기판의 표면 위에 자연적으로 생기는 비정질 자연 산화막의 두께는 10～15Å이다. 그러나 Hf을 증착한 후 단면 TEM으로 HfO₂/Si 계면을 관찰하면 자연 산화막이 Hf 환원으로 제거되기 때문에 비정질 SiO₂ 층은 관찰되지 않았다. 본 실험에서는 HfO2의 두께를 고정하고 Hf층의 두께를 변수로 한 게이트 stack의 물리적 특성을 살펴보았다. 선증착되는 Hf 금속층을 0, 10, 25Å의 두께 (TEM 기준으로 한 실제 물리적 두께) 로 증착시키고 미세구조를 관찰하였다. Fig. 1(a)에서 볼 수 있듯이 Hf 금속층의 두께가 0Å일때 13Å의 HfO₂를 반응성 스퍼터링 방법으로 증착하면 HfO₂와 Si 기판 사이에는 25Å의 계면층이 생기며, 이것은 Ar/O₂의 혼합 분위기에서의 스퍼터링으로 인한 Si-rich 산화막 또는 SiO₂ 박막일 것이다. Hf 금속층의 두께를 증가시키면 계면층의 성장은 억제되는데 25Å의 Hf 금속을 증착시키면 HfO₂ 계면층은 10Å미만으로 관찰된다. 그러므로 Hf 금속층이 충분히 얇으면 플라즈마내 산소 라디칼, 이온, 그리고 분자가 HfO₂ 층을 뚫고 Si 기판으로 확산되어 SiO₂의 계면층을 성장시키고 Hf 금속층이 두꺼우면 SiO/sub X/ 계면층을 환원시키면서 Si 기판으로의 산소의 확산은 막기 때문에 계면층의 성장은 억제된다. 따라서 HfO₂/Hf(Variable)/Si 계에서 HfO₂ 박막이 Si 기판위에 직접 증착되면, 순수 HfO₂ 박막의 두께보다 높은 CET값을 보이고 Hf 금속층의 두께를 증가시키면 CET는 급격하게 감소한다. 그러므로 HfO₂/Hf 박막의 유효 유전율은 단순 반응성 스퍼터링에 의해 형성된 HfO₂ 박막의 유전율보다 크다. Fig. 2에서 볼 수 있듯이 Hf 금속층이 너무 얇으면 계면층의 두께가 두꺼워 지고 Hf 금속층이 두꺼우면 HfO₂층의 물리적 두께가 두꺼워지므로 CET나 EOT 곡선은 U자 형태를 그린다. Fig. 3에서 Hf 10초 (THf=25Å) 에서 정전 용량이 최대가 되고 CET가 20Å 이상일 때는 high-k 두께를 제어해야 하지만 20Å 미만의 두께를 유지하려면 계면층의 두께를 제어해야 한다.

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.194-201
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• 2015

We have investigated the EPR signal properties in 12 components of two mobile phones (LCD, OLED) using electron paramagnetic resonance (EPR) spectrometer in this study.EPR measurements were performed at normal atmospheric conditions using Bruker EXEXSYS-II E500 spectrometer with X-band bridge, and samples were irradiated by $^{137}Cs$ gamma-ray source. To identify the presence of radiation-induced signal (RIS), the EPR spectra of each sample were measured unirradiated and irradiated at 50 Gy. Then, dose-response curve and signal intensity variating by time after irradiation were measured. As a result, the signal intensity increased after irradiation in all samples except the USIM plastic and IC chip. Among the samples, cover glass(CG), lens, light guide plate(LGP) and diffusion sheet have shown fine linearity ($R^2$ > 0.99). Especially, the LGP had ideal characteristics for dosimetry because there were no signal in 0 Gy and high rate of increase in RIS. However, this sample showed weakness in fading. Signal intensity of LGP and Diffusion Sheet decreased by 50% within 72 hours after irradiation, while signals of Cover Glass and Lens were stably preserved during the short period of time. In order to apply rapidly EPR dosimetry using mobile phone components in large-scale radiation accidents, further studies on signal differences for same components of the different mobile phone, fading, pretreatment of samples and processing of background signal are needed. However, it will be possible to do dosimetry by dose-additive method or comparative method using unirradiated same product in small-scale accident.

• Clean Technology
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• v.28 no.1
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• pp.79-93
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• 2022

In this study, an electronics industrial wastewater activated sludge model (e-ASM) to be used as a Water Digital Twin was calibrated based on real high-tech electronics industrial wastewater treatment measurements from lab-scale and pilot-scale reactors, and examined for its treatment performance, effluent quality prediction, and optimal process selection. For specialized modeling of a high-tech electronics industrial wastewater treatment system, the kinetic parameters of the e-ASM were identified by a sensitivity analysis and calibrated by the multiple response surface method (MRS). The calibrated e-ASM showed a high compatibility of more than 90% with the experimental data from the lab-scale and pilot-scale processes. Four electronics industrial wastewater treatment processes-MLE, A2/O, 4-stage MLE-MBR, and Bardenpo-MBR-were implemented with the proposed Water Digital Twin to compare their removal efficiencies according to various electronics industrial wastewater characteristics. Bardenpo-MBR stably removed more than 90% of the chemical oxygen demand (COD) and showed the highest nitrogen removal efficiency. Furthermore, a high concentration of 1,800 mg L^-1 T MAH influent could be 98% removed when the HRT of the Bardenpho-MBR process was more than 3 days. Hence, it is expected that the e-ASM in this study can be used as a Water Digital Twin platform with high compatibility in a variety of situations, including plant optimization, Water AI, and the selection of best available technology (BAT) for a sustainable high-tech electronics industry.

• Korean Journal of Plant Resources
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• v.35 no.5
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• pp.594-606
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• 2022

This study was conducted to figure out the environment factors including vegetation structure and soil characteristics in natural habitats of Sageretia thea, and offers the basic information for habitats conservation and proliferation. The natural habitats of Sageretia thea were located at altitudes between 0~370 m with inclinations ranged as 3~35°. Through the vegetation research, the dominant species of tree layers were found to be divided into four communities. Cornus macrophylla (Com. I), Pinus thunbergii - Cinnamomum camphora (Com. II), Machilus thunbergii (Com. III), and Pinus thunbergii (Com. IV). The Species diversity (H') was 1.397~1.455, evenness (J') was 0.972~0.986, and dominance (D) was found to be 0.014~0.028. As a result of the physicochemical characteristics of soils, habitats soil mainly consisted of sandy soil and sandy loam soil. The average soil pH was 5.28~5.98, electronic conductivity was 0.22~63 ds/m, soil organic matter was 13.33~19.33 cmol⁺/kg, Exchange cations were appeared in the order of Ca²⁺, Mg²⁺, K⁺, and Na⁺. The Ordination result showed that Correlation coefficient between communities and environmental factors were significantly correlated with 4 main factors altitude, electronic conductivity, cation exchange capacity, exchangeable Na⁺. As expected, The result of this study will be helpful information on the preservation and mass production for use.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.3
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• pp.145-154
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• 2022

Due to abnormal weather conditions caused by climate change, natural disasters and damages are gradually increasing around the world. Global climate change as accompanied by warming is projected to exert adverse impact on production of potato, which is known as cool season crop. Even though, role of potato as a food security crop is expected to increase in the future, the climate change impacts on potato and adaption strategies are not sufficiently established. Therefore, this study was conducted to analyze the damage pattern of potatoes due to high temperature treatment and to evaluate the response of cultivars. T he high temperature treatment (35~38℃) induced heat stress by sealing the plastic house in midsummer (July), and the quantity and quality characteristics of potatoes were compared with the control group. T otal yield, marketable yield (>80 g) and the number of tubers per plants decreased when heat treatment was performed, and statistical significance was evident. In the heat treatment, 'Jayoung' cultivar suffered a high heat damage with an 84% reduction in yield of >80 g compared to the control group. However, in Jopung cultivar, the decrease was relatively small at 26%. Tuber physiological disturbances (Secondary growth, Tuber cracking, Malformation) tended to increase in the heat stress. Under heat conditions, the tubers were elongated overall, which means that the marketability of potatoes was lowered. T he tuber firmness and dry matter content tended to decrease significantly in the heat-treated group. T herefore, the yield and quality of tubers were damaged when growing potatoes in heat conditions. T he cultivar with high heat adaptability was 'Jopung'. T his result can be used as basic data for potato growers and breeding of heat-resistant cultivars.