• Journal of the Korean earth science society
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• v.27 no.6
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• pp.643-652
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• 2006

Data of the carbon monoxide concentration observed in Mt. Waliguan in China (WLG), Ulaan Uul in Mongolia (UUM), Tae-ahn Peninsula in Korea (TAP), and Ryori in Japan (RYO) were analyzed for a long period between 1991 and 2004. The annual average concentration of carbon monoxide was the highest at TAP $(233{\pm}41ppb)$ followed by $RYO(171{\pm}36ppb),\;UUM(155{\pm}26ppb),\;and\;WLG(135{\pm}22ppb)$. The seasonal variations being high in spring and low in summer were observed in other areas of Eastern Asia except WLG. TAP was high in carbon monoxide concentration in all seasons compared to WLG, UUM and RYO and shows wide distribution of concentration in the histogram, which is caused by the influence of large-scale air pollution due to its downwind location close to the East Asian continent, China in particular. Also, our data was compared with data measured at Mauna Loa (MLO) in Hawaii. According to the origin of the isentropic backward trajectory and its transport passage, carbon monoxide concentration observed in TAP was analyzed as follows: continental background airflows (CBG) were $216{\pm}47ppb$; regionally polluted continental airflows (RPC) were $316{\pm}56ppb$; Oceanic background airflows (OBG) were $108{\pm}41ppb$; and Partly perturbed oceanic airflows (PPO) were $161{\pm}6ppb$. The high concentration of carbon monoxide in TAP is due to the airflow from East Asian continent origin rather than that from the North Pacific origin. Especially, RPC which passes through the eastern China appeared to be the highest in concentration in spring, fall, and winter. However, OBG was affected by the North Pacific air mass with a low carbon monoxide concentration in summer. The NOAA satellite images and GEOS-CHEM model simulation confirmed a large-scale air pollution event that was in the course of expansion from southeastern China bound to the Korean Peninsula and the Korea East Sea by way of the Yellow Sea.

• Journal of Aquaculture
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• v.21 no.2
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• pp.96-101
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• 2008

To induce of maturation and ovulation, ovary with different development stage of oocytes of sevenband grouper Epinephelus septemfasciatus(n=51, TL $69.1{\pm}1.0$ cm, BW $5.8{\pm}0.3$ kg) rearing indoor-tank in mature and spawning season(June to July) were investigated by cannulation. Female with yolk globule stage oocyte($300{\sim}500{\mu}m$) was injected with human chorionic gonadotropin(HCG, 500 IU/kg BW). Oocytes developed at diameter $300{\sim}700{\mu}m$ in 24 hrs after the HCG injection, and the distribution ratio of over $800{\mu}m$ of oocytes diameter in the cannulated eggs were $91.3{\sim}98.8%(95.1{\pm}3.7%)$ in 48 hrs after the HCG injection. Ovulation was induced from 7 out of 8 female after the HCG injection. The total volume of stripped eggs was 2,480 mL, and the volume of buoyant eggs was 1,360 mL. The fertilization and hatching rates of buoyant eggs were $56.2{\sim}94.9%$ and $70.7{\sim}97.9%$, respectively. These results suggested that HCG 500 IU/kg BW effects on maturation and ovulation of female sevenband grouper with yolk globule stage of oocyte.

• Spatial Information Research
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• v.15 no.2
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• pp.111-121
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• 2007

The GPS positioning offer 3D position using code and carrier phase measurements, but the user can obtain the precise accuracy positioning using carrier phase in Real Time Kinematic(RTK). The main problem, which RTK have to overcome, is the necessary to have a reference station(RS) when using RTK should be generally no more than 10km on average, which is significantly different from DGPS, where distances to RS can exceed several hundred kilometers. The accuracy of today's RTK is limited by the distance dependent errors from orbit, ionosphere and troposphere as well as station dependent influences like multipath and antenna phase center variations. For these reasons, the author proposes Network based GPS Carrier Phase Differential Positioning using Multiple RS which is detached from user receiver about 30km. An important part of the proposed system is algorithm and software development, named DAUNet. The main process is corrections computation, corrections interpolation and searching for the integer ambiguity. Corrections computation of satellite by satellite and epoch by epoch at each reference station are calculated by a Functional model and Stochastic model based on a linear combination algorithm and corrections interpolation at user receiver are used by area correction parameters. As results, the users can obtain the cm-level positioning.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.4
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• pp.282-287
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• 2016

Recently in order to protect the ocean environment and to reduce energy consumption, shipbuilders have been developing highly economized ships. This research analyzed the possibility of adopting the onshore absorption refrigerator to offshore ships having a cooling system with refrigerant by using the waiste heat of the engine jacket cooling water instead of compression refrigerators. The results showed that R236fa could be a suitable medium for absorbing the heat of the absorber and condenser in an absorption refrigerator. The cooling system using R236fa achieved a high COP of 0.798, which is 15% and 5% higher than an air cooling system with a cooling tower and a water cooling system with a heat exchanger, respectively. The cooling system with R236fa achieved high efficiency with a 25% reduction in flow rate of LiBr solution and only 15.7% flow rate of cooling medium as compared to the water cooling system. The heating of sea water by the engine jacket water flowing out from the generator can prevent the crystallization of LiBr solution due to the low temperature of sea water.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.6
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• pp.331-340
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• 1988

Using the oceanographic data during 196s~ 1983, the seasonal variation of the water type in the Tsushima Current is discussed by analyzing the thermosteric anomaly $(\delta_T)$. By investigating with the index of $33.8\%_{\circ}$ in salinity, it is shown that the low saline water inflowed through the Korea Strait affects the variations of water type in surface layer from summer to fall. On the sea surface, the value of $\delta_T$ is affected mainly by the sea surface temperature (SST). However, in summer, $\delta_T$ is temporarily influenced by the transitional characteristic of the surface salinity. It has the minimum value in winter when the SST is the highest and the sea surface salinity is the lowest. In fall, it decreases as the SST decreases. Specifically, the value of $\delta_T$ is 779 cl/t in August in the region of Korea Strait and 667 cl/t in September in the East Coast of Korea. These values are larger than that of the Kuroshio where is 622 cl/t in August. This phenomenon is due to the inflow of low saline water into these area during summer. In loom depth, the seasonal variation of the $\delta_T$ is not so significant as the surface and is mainly dependent on the annual temperature variation. In general, $\delta_T$ decreases as the Tsushima Current flows to the north.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.6
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• pp.447-453
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• 2006

Toxicity of two species of puffer fish, Takifugu porphyreus and Takifugu rubripes, collected from coastal regions of Korea, was determined using a mouse bioassay, In T. porphyreus, the proportion of toxic specimens containing ${\ge}$ 10 MU/g was 58.3% for the ovary, 32.6% for the skin, 12.0% for the gallbladder, 11.6% for the liver and intestine, and 9.3% for the fin; no toxicity was detected in the muscle and testis using the mouse bioassay. The highest toxin levels were 531 MU/g in the liver, 253 MU/g in the intestine, 136 MU/g in the gallbladder, 118 MU/g in the skin, 116 MU/g in the ovary, and 108 MU/g in the fin. The skin, which is used for human consumption, showed significantly high toxicity with an average of $11{\pm}3\;(mean{\pm}SE) MU/g$. Takifugu porphyreus toxicity also exhibited remarkable regional variation. In T. rubripes, the proportion of toxic specimens was 25.0% for the ovary, 15.8% for the liver, 11.1% for the gallbladder, and 5.3% for the fin and intestine; no toxicity was detected in the muscle, skin, or testis. Among the organs, the highest toxin levels were 228 MU/g in the ovary, followed by 112 MU/g in the liver, 28 MU/g in the gallbladder, 18 MU/g in the intestine, 11 MU/g in the fin, and 8 MU/g in the skin. Thus, we found acceptable toxin levels in the edible muscle and skin of T. rubripes and in the muscle of T. porphyreus. However, the skin of T. porphyreus, which showed significantly high toxicity, requires special attention when used for human consumption.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.1
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• pp.37-47
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• 1977

Korea started the Atlantic tuna fishery from 1964 by means of longline, then added bait-boats in 1972. Both fisheries have given the top priority to catch yellowfin tuna(Thunnus albacares). The paper reviews available catch, effort and biological data, estimates some population parameters in order to understand the status of the Atlantic yellowfin tuna as a whole. The main findings are summarized as follows: 1. The total of 476 million hook-equivalent fishing effort was thrown to catch yellowfin tuna in 1974, among which one thired was shared by longliners. 2. The dominant age group becomes younger in both surface and longline fisheries. 3. The recent mortality coefficients were calculated as 1.5 for total mortality and 0.7 for fishing mortality. 4. The weight at recruitment was 2.7 kg in 1973 which was smaller than the regulation size(3.2kg) proposed by ICCAT. 5. The maximum sustained yield was calculated to 95-145 thousand metric tons, which was the level of recent catch. Therefore, it is apparent that the present yellowfin tuna fishery should continue to receive close attention.

• Ocean and Polar Research
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• v.27 no.1
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• pp.67-74
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• 2005

The phonology and reproductive effort of Zostera marina L. (Dongdae Bay and Aenggang Bay) on the southern coast of Korea were investigated from September 2002 to August 2003. The Dongdae Bay(DB) exhibited a finer sediment grain size with richer organic content than the Aenggang Bay(AB). Water temperature at DB site ranged from $7.5^{\circ}C$ in February to $25.5^{\circ}C$ in August, while water temperature at AB site ranged rrom $6.7^{\circ}C$ in February to $25.2^{\circ}C$ in september. Both populations exhibited a perennial lifB span, but the sexual reproductive effort was significantly higher at DB than AB. The reproductive shoots of DB site were developed from February to June 2003, while those of AB site from March to June 2003. At DB site, the frequency of reproductive shoot ranged from 11 to 33%, whereas reproductive shoot of AB did below 5%. Reproductive structures were larger and more abundant at DB, with the exception of number of fruits and seeds per spadix. Water temperature seems most important to regulate the timing of reproductive phase of Z. marina populations for two study sites.

• Proceedings of the Korean Society of Community Living Science Conference
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• 2009.09a
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• pp.98-98
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• 2009

농촌 지역의 인구 감소 및 그에 따른 지자체의 위기의식이 심화됨에 따라 국내에서도 지역마다 각종 인구 늘리기 시책을 실행하고, 중앙에서 도시민 농촌유치 프로그램 지원 시범사업을 기획하는 등 지역 발전의 기본 요건이 되는 인구 감소의 해결을 위한 노력이 가시화되고 있다. 이에 따라 본 연구는 일본의 정주촉진 정책 사례에 대한 고찰을 통해 국내 정책에의 시사점을 도출하고자 한다. 시마네현은 일본 혼슈의 동해 연안에 위치하고 있으며, $6707.26km^2$의 면적에 약 74만 2천 명의 인구(2005)가 살고 있는 지역이다. 시마네현의 총 토지면적 중 약 80%가 산림면적이며, 경지면적은 41,000ha로 약 6%를 차지하고 있다. 이 중 논이 80%를 차지하여 논농사 중심의 농업이 이루어지고 있으며, 풍요로운 수산자원을 보유하고 있어 어업활동도 활발하다. 이러한 시마네현에서는 UI턴의 촉진을 위해 '산업체험사업'을 1996년부터 시행하고 있는데, 농림어업에 관한 산업체험을 실시하고, 체험 후의 거주지로 빈집을 활용하는 사업이다. 현 외 거주자가 시마네현 내에서 일정시기 산업체험을 하고자 할 경우, 월 50,000엔이 지급되며, 거주지 확보가 어려울 경우 트레일러하우스나 빈집활용주택, 공영주택 등을 임대해주고 있다. 또 시마네 현 내에서 30세 미만의 청년 미취업자가 일정기간 산업체험을 실시할 경우, 체험에 필요한 경비의 일부를 제공해주고 있다. 그간의 실적을 보면 연간 평균 105명이 체험에 참가하고 있으며, 2000년 이후 정착률은 50%를 넘고 있다. 총 259개의 체험 장소에서 월 평균 4명이 참가하고 있으며, 업종별 참가자수는 농업 및 기타(관광, 전통공예), 어업, 임업, 축산업의 순서로 많은 것으로 나타나고 있다. 또한 시마네현의 고츠시에서는 '도시와의 공생 교류' 실현을 위한 9가지 중점시책을 설정하고 그에 따른 사업을 실행하고 있다. 농산어촌의 취락을 유지하는 것이 첫 번째 중점시책으로서 이를 위해 빈집을 활용한 정주와 교류가 활발히 이루어질 수 있도록 주거 정보를 수집, 관리, 웹을 통해 제공하고 있으며, 농지 유동화 및 농림수산물의 직거래 시스템 확립에 주력하고 있다. 이 밖에도 UI턴자 확보를 위해 지역에서 살고, 일하고, 즐기는데 대한 일체적인 정보 제공 시스템을 마련하고 있으며, '고향교육'을 통해 지역에 대한 애착심을 기르는 동시에 지역에서의 취업 지향을 높이는데 힘쓰고 있다. 농촌 정주촉진을 위한 사업 내용면에서는 일본과 우리나라 간 큰 차이가 없다. 그러나 사업에의 의지와 방향 설정, 사업 추진체계 및 운영방식 등에서 발견되는 차이를 주시함으로써 농촌 지역 인구 증가에 보다 실질적으로 기여할 수 있는 정책으로 만들어가야 할 것이다.

• Journal of Life Science
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• v.20 no.9
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• pp.1294-1298
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• 2010

White spot syndrome virus (WSSV) is one of the most virulent viral agents threatening the penaeid shrimp culture industry. This study was carried out to evaluate the susceptibility of the sand shrimp, Crangon affinis, to WSSV as an alternative experimental model. WSSV caused 100% mortality in C. affinis within 7 days after experimental infection by immersion. Based on challenge studies, it was confirmed that C. affinis could be a potential host in WSSV transmission. Also, the neutralization of WSSV was carried out using an antiserum raised against recombinant envelop protein rVP466 to evaluate the WSSV infection mechanism. A constant amount of WSSV (at $1{\times}10^4$ diluted stocks) was incubated with various amounts of antiserum and then mixed to 20 l reservoir for the immersion challenge of C. affinis for neutralization. At 5 days post challenge, the shrimp in the positive control immersed in the immersion reservoir containing WSSV stock showed 100% mortality. The shrimps challenged with the 3 different mixtures of WSSV and rVP466 antiserum (1:0.1, 1:0.5 and 1:1) showed 100%, 68.8% and 68.8% mortality at 14 days post challenge, respectively. These results indicated that the antiserum raised against rVP466 could block WSSV infection in C. affinis. Therefore, this study confirmed that C. affinis can be naturally infected by WSSV as another potential host and that C. affinis can be used as an alternative experimental animal instead of penaeid shrimps.