• Korean journal of applied entomology
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• v.23 no.1 s.58
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• pp.22-27
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• 1984

The effects of solarization on the suppression of soilborne plant pathogen and the growth promotion of cucumber plants were examined in artificially infested soil by vinyl mulching and not mulching from July 25 to August 25, 1983. During the solarization period, the highest temperatures were $58^{\circ}C,\;45^{\circ}C,\;and\;42^{\circ}C$, at 5cm, 15cm, and 25cm of soil depth respectively. The inoculum of cucumber wilt pathogen, Fusarium oxysporum f. sp. cucumerinum, was mixed with soil 30cm deep and saturated with water. The pathogen was completely killed after 30dys of solarization in 5cm soil depth and 98 percent of inoculum was eliminated in 15cm soil depth. But the survival rate of the fungi in 25cm soil depth of solarized plot did not show significant differences compared with those in nontreated plot in 5cm and 15cm depth. Although some of the pathogenic fungi might survive from solarized soil in 15cm and 25cm depth, the ability of microconidia production was reduced significantly The number of microconidia grown on Komada's medium in isolates the primary colonies from solarized soil was less than that in isolates from nontreated soil approximately by one fourth. The first subcultured solates from the solarized soil grown on potato dextrose agar also produced a small amount of microc. onidia compare with that of subcultured isolates from nontreated soil. Cucumber seedlings planted in the soil collected from solarized plot grew much better than that in the soil from nontreated plot at any of soil loved, especially in 5cm of soil depth. And the fruits harvested from cucumber plants grown in the solarized plot were more in number and leavier in weight than that from nontreated plot. Besides the typical symptom development, significant growth suppression wvas recognized with increase of inoculum density of F. oxysporum f. sp. cucumerinum at early stage of cucumber seedlings in steam sterilized soil.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.2
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• pp.141-148
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• 2011

This feeding experiment was conducted to investigate the effects of dietary inclusion of various additives on growth performance, hematological parameters, fatty acid composition, gene expression and histopathological changes in juvenile olive flounder (Paralichthys olivaceus). Eleven isonitrogenous (49% crude protein) and isolipidic (10% crude lipid) experimental diets were formulated: no additives (Con); 5% kelp meal (Ke); 10% krill meal (Kr); 1% garlic powder (Ga); 1% citrus meal (Ci); 3% onion powder (On); 1% ginger powder (Gi); 1% mugwort powder (Mu); 1% licorice powder (Li); 1% wasabi powder (Wa); and a mixture (Mix) of these additives. Three replicate groups of juvenile flounder (average weight of 8.5 g) were fed one of the experimental diets to visual satiety twice a day for 15 weeks. The dietary inclusion of additives did not affect survival, weight gain, specific growth rate feed efficiency, daily feed intake, daily protein intake, protein efficiency ratio, hepatosomatic index and visceralsomatic index of the fish. Plasma triglyceride levels were significantly lower in fish fed the Ke, Ga, On, Gi, Mu, Li, and Mix diets than in fish fed the control diet. Plasma glucose, glutamic oxaloacetic transaminase and total cholesterol did not differ among dietary treatments. No significant difference was observed in fatty acid composition and lipid content of the dorsal muscle in fish fed the experimental diets. Myosin gene expression did not differ significantly among treatments after 5 weeks but was significantly lower in fish fed the Kr, Ci, Li, and Mix diets than in control group after 15 weeks. Histopathological analysis showed mild gill hyperplasia and mild necrosis of liver parenchymal cells in several individuals of each experimental group. These conditions were also observed in the control group and were not thought to be related to the inclusion of feed additives. The present findings indicate that the dietary inclusion of additives did not affect growth performance, fatty acid composition, gene expression, and histopathological changes in juvenile flounder. However, plasma triglyceride content may be reduced by supplementation with 5% kelp meal, 3% onion powder, 1% garlic powder, 1% ginger powder, 1% mugwort powder, and the additive mixture.

• Geophysics and Geophysical Exploration
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• v.9 no.4
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• pp.261-270
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• 2006

Two-dimensional (2-D) inversion of magnetotelluric (MT) data for two survey lines having south-north direction from Jeju Island has been carried out. Broad band MT sounding curves with good quality could be gathered by performing audio-frequency magnetotelluric (AMT) survey during the MT survey and by operating the remote reference in Kyushu Island, Japan. Comparison of the 2-D inversion model using MT band only and that using both AMT and MT bands for the field data as well as for the data from numerical 2-D modeling said that high frequency information from AMT survey can be useful for interpreting not only the shallow part but also the deep structures, especially when the formation is resistive. The 2-D inversion models of field data show a thick layer having around 10 ohm-m in the depth of a few hundred meters throughout the survey area, which can be considered as the unconsolidated sedimentary layer. And they also show a conductive anomaly at the central part of each survey lines. It can be either the effect of the surrounding sea water, or the structures due to ancient volcanic events. But unfortunately by now, we do not have any further information about the anomaly.

• Journal of the Korean GEO-environmental Society
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• v.13 no.6
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• pp.83-90
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• 2012

Generally, the effect of the cement deep mixing method on the improvement of clay ground is far greater than the effect of physical improvement. Although it leads to great improvement strength in the initial stage, there are not many constructional precedents in Korea and it is hard to manage quality according to the cement-clay mixing method. In order to figure out the strength characteristics according to the mixing ratio of cement, sand, and clay and the improvement characteristics of weak ground according to the forms of the specimens to be improved, marine clay was used in this study to conduct the uniaxial compression test and soil bin model test. The test piece specimens for the uniaxial compression test were mixed with sand in a fixed ratio with the criterion of the water cement ratio. The cement was mixed with clay in the ratios of 10%, 20%, 30%, and 40% to the clay weight. The moisture content of the soil ground was made in the ratios of 40%, 60%, and 80%. The test piece specimens went through curing by moistening for 7, 14, and 28 days and underwent the uniaxial compression test according to the curing period. For the bearing test, the soil bin models were made and the ground improved in the Mat type was formed. After that, the bearing strength was compared in this study according to the improvement ratio and analyzed the intervening effect between the walls of the improved specimens.

• Current Industrial and Technological Trends in Aerospace
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• v.5 no.1
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• pp.75-92
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• 2007

2002년 프론티어사업의 일환으로서, 10년간 1200억의 예산으로 미래형 신개념비행체 기술개발사업을 시작한 스마트무인기사업은, $2002{\sim}2003$년 수행한 개념연구를 통해 미래형 신개념 고속 수직이착륙 항공기 개념으로서 틸트로터 개념을 선정하고 이의 개발에 매진하고 있다. 사업단에서는 우선, 항공 선진국에서 지난 반세기 동안 시행한 다양한 비행체 개념연구결과에 대해 자체적인 비교 분석 및 국제공동 연구를 근간으로하여, 당시 틸트로터에 필적하는 가능성을 보였던 스탑트로터(보잉사), 복합자이로콥터(카터콥터사) 개념이 아닌, 틸트로터 비행체의 기술개발을 결정하게 되었다. 각각의 비행체 개념이 갖는 위험성과 도전성, 그리고 소요기술, 설계특성, 개발 위험도 등에 대한 면밀한 분석을 기초로 한 사업단의 체계적 의사결정은 주효했다. 스탑트로터개념은 비행시험의 잇단 실패와 지연/잠정 중단사태가 이어졌고, 복합자이로콥터 또한 잇단 비행사고로 2002년 기록한 148kts를 능가하는 고속성능 시현에 지금까지 실패함으로써, 실용화 가능한 고속수직이착륙기로서의 검증을 위해서는 해결해야할 기술적 과제가 많이 남아있음을 보여주고 있다. 반면, 틸트로터 개념의 경우 V-22의 설계 수정형에 대한 성공적인 비행시험완료 및 인증획득으로 전면양산승인이 2005년 결정되어 458대가 (미해병대(360), 해군(48), 공군(50)) 납품될 예정이고, 2010년 인증획득을 목표로 민수용으로 개발중인 BA609의 순조로운 비행시험진행, 무인기로 개발된 Eagle Eye 기술시현기의 비행 시험성공과 2003년 미 해양경찰청으로부터 Deep Water 프로그램의 장거리 순찰임무 주력기종 선정과 같이 군용, 상용, 무인용 고속 수직이착륙 시장의 전 방위적 진입이 현실화되고 있다. 이에 따라 항공업계의 반응은 2가지 방향으로 나뉘고 있다. 하나는 유럽의 ERICA 프로그램과 같이 틸트로터 기술 개발을 서두르자고 주장하는 방향이고, 다른 하나는 시콜스키의 X2 프로그램과 같이 틸트로터와는 차별화된 독자적인 고속 수 직이착륙 비행체 개념 개발을 시도하는 것이다. 이러한 배경으로 국내 독자적인 기술력으로 지난해까지 일구어낸 성공적인 스마트무인기 상세설계 종료 및 축소형 비행체 전환비행성공은 그 의의가 매우 크다고 할 수 있다. 본 논문은 틸트로터 개발사를 통해, 신개념 비행체 개발의 어려움과 교훈을 알아보고, 세계에서 2번째로 틸트로터 기술을 개발하고 있는 스마트무인기 사업의 현황과 기술적 특징 및 의의의 정리, 그리고 틸트로터의 대안으로 진행중인 새로운 고속 VTOL 비행체 연구현황에 대한 소개 와 간단한 기술적 평가를 포함시켰다.

• Journal of Korea Port Economic Association
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• v.25 no.1
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• pp.63-86
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• 2009

With increasing uncertainty of energy market in the world, the policies for the energy resource security have become crucial Several countries with poor energy resource like Netherlands and Singapore have pursued the policy for becoming an oil hub in the region. Singapore has been an oil hub in East Asia for a long time not only because it is well located with a large number of countries exporting and importing oil but it has also pursued strong policies to become an oil hub while establishing favourable institutional, regulatory and business environment for accommodating major refineries and petro-chemical companies. However with growing trading volume of petroleum products in Northeast Asia and a record high price of oil in these days, the necessities of another oil hub in the region are considered in order to reap benefits of the security of economical and stable oil. South Korea is situated astride the main North Pacific shipping route, with deep water ports and proximity to Chinese and Japanese industrial centres that make tank terminal operators Ideal choices for the oil hub in Northeast Asia although it has several disadvantages such as lack of independent storage facilities, underdeveloped oil trading market and unfavourable business friendly climates etc. This study is focused on examining the globalization strategies of tank terminal operators such as Vopak, Oiltanking and Odfjell in order to suggest the policy implications for becoming an oil tub in Northeast Asia.

• Geophysics and Geophysical Exploration
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• v.14 no.3
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• pp.227-233
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• 2011

Attention has been focused on geothermal energy as an alternative energy because it is continuously operable without external supply. Most of geothermal anomalies in Korea are related to deep circulation of groundwater through a fracture system in granite area. Therefore it is very important to understand the distribution of the fracture system which is the main channel of ground water. In this research, we constructed the velocity models with a fracture system and the layered sediments, respectively, and generated synthetic data sets with them to verify the presented vertical seismic profiling (VSP) preprocessing scheme. We compared the results from conventional VSP preprocessing flow to those from VSP preprocessing flow considering fracture system. We noticed that the preprocessing flow considering fracture system retains more sufficient signal including down-going wave than conventional preprocessing. In addition, we applied 3D VSP prestack phase screen migration to the preprocessed reversed VSP (RVSP) data from Seokmo Island so that we were able to image fracture structure of the geothermal site in Seokmo Island.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.2
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• pp.116-121
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• 2014

In order to study the improvement of the multi stage regeneration cycles, muti-stage processes were applied to the cycles, respectively or together. The kinds of the cycles are multi stage reheater cycle (MS) and multi stage reheater regeneration cycle (MSR). Working fluid used was R134a and R245fa. Temperature of the heat source was $65^{\circ}C$, $75^{\circ}C$, and $85^{\circ}C$, and temperature of the heat sink was $5^{\circ}C$. Optimization simulation was conducted for improving the gross power and efficiency with multi stage reheater regeneration cycle for ocean thermal energy conversion(OTEC) with changing of a heat source, kind of the working fluid, and type of the cycle. Performance analysis of the various components was simulated by using the Aspen HYSYS for analysis of the thermodynamic cycle. R245fa shows better performance than R134a. This paper showed the most suitable working fluid with changing of a heat source and the kinds of working cycle. Compared to each other, MS showed better performance at gross power and MSR showed higher cycle efficiency.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.399-422
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• 1995

The purpose of this study was to investigate a fragment of possibility of pulpotomy with the Nd-YAG laser by the observation of pulpal healing process and the fine structural changes of the fibroblasts of the remaining pulpal tissues. Class V cavities on !55 teeth from 4 adult dogs were prepared and the pulp chambers were opened with a sterilized round bur. In the control group(19 teeth), the exposed coronal pulps were excised by a sharp excarvator. After bleeding was controlled with the sterilized cotton pellets, calcium hydroxide powder was applied on the remaining pulpal tissues and the cavities were sealed with Z.O.E. In the experimental group 1 : the pulpotomy with laser-calcium hydroxide powder application group(l9 teeth), the exposed coronal pulps were excised by Nd-YAG laser(10 watts power, 2 psi water, 20 psi air) for 2 or 3 seconds and calcium hydroxide powder was applied on the remaining pulpal tissues and the cavities were sealed with Z.O.E. In the experimental group 2 : the pulpotomy with laser-no calcium hydroxide powder application group(17 teeth), after amputating the coronal pulps with Nd-YAG laser as the experimental group 1, the remaining pulpal tissues were covered with stenilized aluminum foil and the cavities were filled with Z.O.E. The animals were sacrificed at the intervals of 1, 2, 3 and 4 weeks. All the teeth were rouutinely processed and the remaining pulpal tissues were observed by the light microscope and electron microscope. The results were as follows : 1. In light microscopic findings, there was no significant difference of the inflammatory response in the remaining pulpal tissues between the control group and the experimental groups. In both of the experimental group 1 : pulpotomy with laser-calcium hydroxide powder application group and the control group, the dentin bridges were observed after 2 weeks and the structure of the dentin bridge was almost same. In the experimental group 2 : pulpotomy with laser-no calcium hydroxide powder application group, the fibrous layers instead of dentin bridge were observed on the superficial portion of the remaining pulpal tissues after 2 weeks and they were consisted with densely crowded active fibroblasts. 2. In the electronmicroscopic findings, the active fibroblasts in the experimental groups were more frequently observed than in the control group at 1 week. But active fibroblasts were found with same frequency after 2 weeks in all of the control group and the experimental groups. 3. General distortions of the cell such as loss of the cell membrane, vaculoization of the cell etc. were observed at the suberficial layer of the remaining pulpal tissues and the carbonization was found in the dentinal wall in 1 week of the experimental groups. 4. In the experimental group 2 : pulpotomy with laser-no calcium hydroxide powder application group, the activity and the density of the fibroblasts in the fibrous layer were more than those in the deep portion of the remaining pulpal tissues after 2 weeks. 5. In the control group, bacteria such as cocci and bacilli were observed frequently, but in the experimntal groups, they could not be observed.

• Restorative Dentistry and Endodontics
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• v.34 no.2
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• pp.103-112
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• 2009

The purpose of this study was to compare the effect of curing methods of adhesive resins and resin cements in the root canal. Crown portions of 32 single-rooted mandibular premolars were removed. Routine endodontic treatment was done, and 9 mm deep post spaces were prepared within root canals. No.3 FRC Postec posts (Ivoclar-Vivadent AG, Liechtensteih) were cemented in the post spaces by self-(SC) or light-curing (LC) using two dual-cured adhesives (Adper Scotchbond multi-purpose plus and Exite DSC )and resin cements (RelyX ARC and Variolink II). They were assigned to 4 groups (n=8): R-SC, R-LC, V-SC, V-LC group. After stored in distilled water for 24 hours, each root was transversally sectioned with 1.5 mm thick and made three slices. The specimens were subjected to push-out test in a universal testing machine (EZ Test, Shimadzu Co., Japan) with a crosshead speed of 1 mm/min. The data were analyzed with repeated ANOVA and one-way ANOVA. Also the interface of post-resin cement and resin cement-canal wall of each group was observed under FE-SEM. When fiber posts were cemented into the root canal using total-etch adhesives, the bond strength and adaptation between post and root canal dentin was affected by curing method. Self-cure of adhesives and resin cements showed higher bond strength and closer adaptation than light-cure of them.