• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.3
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• pp.134-144
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• 2009

Paleoproductivity changes in the central part of the Bering Sea since the last glacial period were reconstructed by analyzing opal and total organic carbon (TOC) content and their mass accumulation rate (MAR) in sediment core PC23A. Ages of the sediment were determined by both AMS $^{14}C$ dates using planktonic foraminifera and Last Appearance Datum of radiolaria (L. nipponica sakaii). The core-bottom age was calculated to reach back to 61,000 yr BP. and some of core-top was missing. Opal and TOC contents during the last glacial period varied in a range of 1-10% and 0.2-1.0%, and their average values are 5% and 0.7%, respectively. In contrast, during the last deglaciation, opal and TOC contents varied from 5 to 22% and from 0.8 to 1.2%, respectively, with increasing average values of 8% and 1.0%. Opal and TOC MAR were low ($1gcm^{-2}kyr^{-1}$, $0.2gcm^{-2}kyr^{-1}$) during the last glacial period, but they increased (>5 and >$1gcm^{-2}kyr^{-1}$) during the last deglaciation. High diatom productivity during the last deglaciation was most likely attributed to the elevated nutrient supply to the sea surface resulting from increased melt water input from the nearby land and enhanced Alaskan Stream injection from the south under the restricted sea-ice and warm condition during the rising sea level. On the contrary, low productivity during the last glacial period was mainly due to decreased Alaskan Stream injection during the low sea-level condition as well as to extensive development of sea ice under low-temperature seawater and cold environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.503-510
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• 2020

Eco-friendly mountain railways operate on concrete rack tracks embedded on existing sharp curved and steep roads to preserve the environment in mountainous areas. Owing to the narrow roads, single lines are inevitable, and many branches are required. In branches, previous switchers and heating devices cannot be applied, because of the limited spacing for the rack and the slow removal of thick ice. To solve these problems, a switch and a heating device have been developed. The switcher changes the line by moving the block of concrete track with hydraulic actuators. The lack of discontinuity reduces the derailment risk and makes locking simple. The heating device uses high frequency induction coils to increase the efficiency and melt the thick ice rapidly. The prototype switcher and heating device were produced and operated to prove their performance. The heating device yielded a 10 times greater efficiency than the previous one. The switcher and heating device are the essential core technologies for the operation of mountain trams in winter and contribute to the spread of mountain railways to domestic or foreign resort areas by enhancing safety and efficiency. In addition, they can provide transportation rights to local residents in poor winter traffic, and bring about tourism and local economic growth.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.15-21
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• 2015

Natural gas fuel has known to be very promising in terms of abundancy and economic value. Therefore it is widely treated as research topics in a variety field of production, storage and utilization. Natural gas has become one of the major sources for the power generation by using internal combustion engines(ICE). Development of natural gas fuel injection device should be preceded to realize a reliable natural gas fuel supply system for a MW class power generation reciprocating ICE. In this research, an injection valve which consists of solenoid and body part with a moving plate was designed and its dynamic performance was experimented in the engine-like environment. As a result of the experiments, linearity of flow rate was obtained and overall around 2ms of response time was observed at the pressure difference of 1bar. In addition, more than 100Liter/min(@2Hz) of gas flow rate was witnessed, which is expected to be adequate for the fuel supply system of a MW class natural gas engine.

• Journal of the Mineralogical Society of Korea
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• v.15 no.1
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• pp.22-32
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• 2002

Mineral composition and chemistry of the clay minerals in the three cores from the continental shelves of South Shetland Islands (NCS09) and Anberse Island (GC98-2), and from the fjord of King George Island (A10-01) were determined by X-ray diffraction and electron microprobe analysis in search of the distributions and origin of the clay minerals in the Antarctic marine sediments. Smectite content is relatively high in NCS09 regardless of core depths (av. 8.3%), but low in GC98-2 (1.1%). In Al0-01, smectite content is higher in the upper section than in the lower section. Kaolinite was not detected from all the cores in this study Yellow to yellowish green clay granules were commonly scattered in the sediments of NCS09 cores. The clays contain 16.97% and 2.53% $Fe_2$$O_3$와 $K_2$O. Average structural formula of the clay indicates ferrian beidellite . The (Fe, K)-rich smectite of NSC09 must have been derived from relatively young basaltic volcanics altered by reaction with seawater near Shetland Islands by glacial erosion or eolian process related to volcanic eruption. GC98-2 nearer to Antarctic continent is very low in smectite content. In A10-01, the lower diamicton was deposited from the glacial erosion of smectite-free ancient volcanics in the interior of King George Island, while the upper section was derived from the smectite-bearing terrestrial debris and eolian materials after retreat of glaciers in Marian Cove and ice cover in Barton Peninsula. Thehigh K contents of smectites suggest the interstratification of illite and smectite layers, which might be observed by future TEM lattice fringe imaging.

• Journal of the korean society of oceanography
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• v.37 no.1
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• pp.27-34
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• 2002

We measured the alkenone concentration of bulk sediments from a piston core collected from the Ulleung Basin in the East Sea in order to reconstruct past sea surface temperatures (SST). Sediment ages are well constrained by AMS $^{14}C$ dates of the planktonic foraminifera Globigerina bulloides. Coretop alkenone SST calibration with modern surface temperatures and sediment trap dat (Hong et al., 1996) indicate that the SST estimated from alkenones most likely represent the temperatures of late fall. Downcore variations in the alkenone saturation index indicate that between 19 and 15 kyr BP the surface waters were about $3^{\circ}C$ warmer than today. Between 15 and 11 kyr BP, the temperatures were about $3^{\circ}C$ lower than today. A rapid SST increase of about $3^{\circ}C$ occurred at approximately 10 kyr BP. After considering the factors which might influence the SST reconstruction from the $U^{k'}_{37}$ values, we conclude that the alkenone temperature estimates are reliable. The reason for glacial warming in the East Sea is not clear, although there is a possibility that it could be caused by shift in the season of maximum alkenone production from summer during the last glaciation to late fall during the Holocene. Cooling between 15 and 11 kyr BP may be due to inflow of cold water into the East Sea such as via the Oyashio Current or ice-melt water. Warming at the early Holocene could be due to inflow of the Tsushima Current into the East Sea through the Korea Strait.

• Journal of Life Science
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• v.14 no.2
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• pp.368-373
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• 2004

We have obtained fertile transgenic rice plants resistant to the broad spectrum herbicide Bast $a^{(R)}$ (active ingredient phosphinothricin, PPT) by PEG-mediated transformation procedure. The plasmid pCaMV35S::Bar was used to deliver the bar gene into embryogenic suspension culture-derived protoplasts of rice (Oryza sativa L.). Transformed plants were regenerated and selected on medium containing 15 mg/l of phosphinothricin. Stable integration and expression of the bar gene in transgenic rice plants was confirmed by Southern and Northern blot analysis. Transgenic $R_1$ plants were also confirmed by assays for phosphinothricin acetyltransferase (PAT) activity. The bar gene was expressed in the primary transgenic rice plants and in the next generation progeny, in which it showed a 3 : 1 Mendelian inheritance pattern. Transgenic $R_1$ and $R_2$ plants were resistant to the herbicide Bast $a^{(R)}$ when sprayed at rates used in field practice.ice.

• Journal of Appropriate Technology
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• v.7 no.1
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• pp.26-32
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• 2021

In the process of vaccine delivery and vaccination, temperature is mostly controlled by an insulated containers containing ice. Moreover, amount of wasted vaccine is significant because the temperature of the vaccine is not properly controlled. A core challenge of vaccination is temperature data monitoring, since it is critical for managing and operating strategical vaccination by health organizations. In this research, a real-time monitoring vaccine carrier system was developed. Temperature, location, and power consumption data of the vaccine carrier were monitored and working performances of the vaccine carrier were tested in both Korea and Tanzania (Arusha and Kilimanjaro regions). For both places, Short Message Service (SMS) communication method was used to send information of the carrier's status. As a result, the monitoring system was able to transmit and receive real-time data of the vaccine carrier status while the vaccine carrier was tested. The vaccine status data can be accessed from any location through the cloud server and web-based user interface.

• The Journal of the Korea Contents Association
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• v.15 no.5
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• pp.537-549
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• 2015

The purpose of this study is to analyze the characteristics of two local festivals, already recognized as a successful regional cultural festival, over a period of time to apply the product life cycle theory. As a result of the analysis of the two festivals, in introduction stage, the festival organizers have focused mainly on settling down the festival's core programs and raising awareness on the subject of the festival for the stimulation for basic demands. Second, for maintaining increasing demands, the qualitative improvement of the core program, the development of new programs and the expansion of the programs for the visitors' convenience and safety were focused on. In addition, strategies for promoting awareness of the festival had modified the strategy to promote on the contents and programs of the festival, as well as public relations strategy, not only domestic but also the foreign countries, was established and fulfilled. Lastly, in maturity stage, to overcome declining the number of visitors and economic effect both festivals have showed providing sophisticated programs for the visitors' convenience and safety, improving service quality through the development of the existing programs, providing economic benefits such as admission cuts or giving gift certificates and expanding number of foreign visitors with strengthening the promotion that was implemented in growth stage and enhancing the better image of the festival through the social contribution. Therefore, strategies for the each stage mentioned above present the significant policy implications for festival organizers who were planning to establish a new festival or implementing a festival with experiencing the tepid growth.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.493-501
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• 2016

In this study, core technologies of a traction system on a mountain tram operating on the track of mountain road full of sharp curves and steep gradients were developed. In domestic mountain resort areas, sometimes the transportation service is not provided in winter because of ice and heavy snow on roads, so a mountain railway service independent of the climate and geographic conditions is needed. A traction system was designed taking into account of the power of a traction motor to climb the gradient of 120 ‰, which is common in domestic mountainous areas. and power transmission system was designed to consider the installation space for the traction system. In addition, a reduction gear and a propeller shaft were developed. An elastic pinion was developed and applied to the rack & pinion bogie system for steep gradient so that noise and vibration generated by contact between the steel gears could be reduced. Impact comparison tests showed that the vibration level of the elastic pinion is one-third lower than that of previous steel pinion. Independent rotating wheels and axles were developed for the bogie system to operate on the sharp curve of a 10 meter radius. In addition, the band braking system was developed to enhance the braking force during running on the steep gradient. A test for the braking force showed it exerts the required braking force. The performance of the developed core components were verified by the tests and finally they were applied to the bogie system running on the track of steep gradient and sharp curve.

• Journal of the Mineralogical Society of Korea
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• v.28 no.1
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• pp.71-81
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• 2015

This study was carried out in order to investigate the mineralogical characteristics of the core sediments (03GHP-02 and HB13-2), obtained from the Ulleung Basin and Hupo Basin, Korea. The results on mineral compositions, clay mineral compositions, and the total contents and sequential extraction of different fractions of the phosphorus in core samples showed that those values are different in two cores and also at different depths. In both samples, mineral compositions were the same, composed mainly of quartz, microcline, albite, calcite, opal A, pyrite, and clay minerals (illite, chlorite, kaolinite, and smectite). However, the sample from Hupo Basin contains more opal A. Both samples, especially the ones from Hupo Basin contains more smectite than those reported from East Sea, indicating the influence of paleo-Hwangwei River and the Tertiary Formation of Korea Peninsula. For the samples from Uleung Basin, at 0.7-3.5 m range in depth, the low content of opal A and the low illite crystallinity index can be inferred to indicate the relatively cool climate, corresponding to the ice age. Also, the content of total phosphorus was low in those samples. It was reported that East Sea at that time was isolated from the neighboring seas due to the decrease of the sea level, and as a result, the influx of sediments was supposed to be little through the strait and rivers. For the samples from Hupo Basin, there is no significant changes in clay mineral composition and the distribution of phosphorus with increasing depth. This little change can be interpreted to indicate that the sediments comprising the core might be deposited in a relatively short period of time or deposited in sedimentary environment in which there's no significant changes in sediment supplies. The values of crystallinity index of clay minerals are high in those samples, indicating that it was relatively warm during that time. Although the increase of fluctuation pattern can be observed, showing that the climate of this period often changed, it is supposed that it was generally warm.