• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.151-154
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• 2002

AP/RPCVD를 이용하여 $650^{\circ}C$의 저온에서 실리콘-게르마늄의 선택적 단결정 성장 (Selective Epitaxy Growth: SEG) 을 수행하였다. 본 실험에서는 $SiH_4$, $GeH_4$ 그리고 HCl 가스를 사용하여 잠입시간 동안 실리콘-게르마늄막을 성장시키고 연속해서 HCI 가스만을 주입하여 산화막 위에 형성되어진 작은 결정입자들을 식각하는 공정을 반복적으로 수행하였다. HCl 의 식각에 의해 한 주기의 잠입기 후에도 다시 잠입기가 존재함을 확인하였고, 이 성장법을 통하여 한 주기의 잠업시간 동안 증착할 수 있는 두께 이상으로 실리콘-게르마늄막의 선택적 성장이 가능하였다. 이는 저온 선택적 실리콘-게르마늄 성장 시 RPCVD에서 보이는 낮은 선택성과 $SiH_4$의 짧은 장입시간으로 인해 원하는 두께까지 확보하기 힘든 단점을 극복한 것이다. 선택성을 향상시키기 위해 실리콘-게르마늄 증착중 주입된 HCI의 유량에 따라 잠입시간과 증착속도에 영향을 주었으며, 연속공정을 위한 식각공정은 20sccm의 HCI을 20초간 주입하여 선택성을 유지하였다. 또한 보론 불순물의 첨가가 선택적으로 성장되는 박막의 결정성에 미치는 영향도 분석되었다.

• Journal of Aquaculture
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• v.16 no.4
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• pp.229-232
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• 2003

Survival with various conditions (water temperature, salinity and air exposure) and sand immersion ability for release of surf clam, Spisula sachalinensis spats, which were artificially seed produced, were investigated. Survival with water temperature conditions of spats showed no difference within the range of 4∼28 $^{\circ}C$ for 10 days. In salinity conditions, survival (%) of spats showed more than 50% in over 22 psu. In air exposure conditions, survival (%) of spats air exposed for 12 hours was no difference within below 2$0^{\circ}C$, however, that of spats air exposed for 16 hours showed below 50% at $25^{\circ}C$. In sand immersion ability, the immersion time was increased with the increase of shell length, and the immersion rate was decreased. Spats of below 15 mm in shell length were emersed more than 90% within 10 min. There was no difference in the immersion time and the immersion rate with the grain sizes of the sand bottom.

• Journal of Aquaculture
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• v.20 no.2
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• pp.127-131
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• 2007

In order to obtain the basic biological data for effective seed production of Protothaca jedoensis, the influence of sediment condition on its immersion rate was investigated. Immersion rate of P. jedoensis spats was investigated in the different substrate groups; mud, fine sand, medium sand and coarse. In 72 hours, immersion rate and survival rate of spat was 90.0 and 90.0, 76.7 and 98.3, 61.7 and 86.7, and 85.0 and 93.3%, respectively. And also, survival rates of the groups were 90.0%(mud), 98.3%(fine sand), 86.7% (medium sand) and 93.3% (coarse sand) respectively. The immersion time and rate of spat was increased with an increase in shell length.

• The Korean Journal of Malacology
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• v.23 no.1
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• pp.1-8
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• 2007

The influence of individual size, sediment, gain size, water temperature, salinity and air exposure on burrowing rate was investigated in order to obtain the basic biological data on applying shellfish farm for a sustainable production of ark shell, Scapharca broughtonii (Schrenk). The burrowing rate on individual size 300 minutes after starting the experiment was the highest in the shell length $16.3\;{\pm}\;1.2\;mm$, 97.7%. The highest burrowing rates were 97.0% in $12.8\;{\pm}\;0.8\;mm$, 96.7% in $9.2\;{\pm}\;1.0\;mm$, and 96.3% in $5.9\;{\pm}\;0.7\;mm$. The clams over 6 mm of shell length had burrowing ability and the burrowing rate was not related to the shell size. The burrowing rate depending on the kind of grain at the bottom after 300 minutes was the highest, 98.3%, in the mixture of sand and silt with a ratio of 75:25. The rates were 98% in silt (100%), 97.3% in mixture sand and silt with a ratio of 50:50, 97.3% in sand and silt ratio of 25:75, and 86.3% in sand (100%) in this specific order. On grain size of the soil in the seafloor, the burrowing rates after 300 minutes was at its highest in the group of sand in pore size 1 mm with 85.0%, and the $12\;{\mu}m$ to 1 mm in the grain size was fitted to burrowing of artificial seed. In the case of water temperature, the burrowing rates were at its highest after 300 minutes. In $30^{\circ}C$ group, the rate was 96.7% and in $25^{\circ}C$ and $20^{\circ}C$, 90.0%. The rates decreased as the water temperature decreased below $15^{\circ}C$. The burrowing rates on salinity were the highest in 30 psu with 93.3% and at 15 psu and below, there was no noticeable change in the burrowing rate. On air exposure, the burrowing rates after 300 minutes were the highest in 1 hour with 93.3%, and remarkably decreased as air exposure time is longer after 12 hours of air exposure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.182-185
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• 2002

자기정렬구조의 실리콘-게르마늄 이종접합 트랜지스터에서 $f_{max}$를 높이기 위한 방안으로 베이스의 저항 값을 감소시키고자 외부 베이스에 실리콘 및 실리콘-게르마늄 박막을 저온에서 선택적으로 성장할 수 있는 방법을 연구하였다. RPCVD를 이용하여 $SiH_{2}Cl_{2}$과 $GeH_{4}$를 소스 가스로 하고 HCI을 첨가하여 선택성을 향상시킴으로써 $675\sim725^{\circ}C$의 저온에서도 실리콘 및 실리콘-게르마늄의 선택적 에피성장이 가능하였다. 고온 공정에 주로 이용되는 $SiH_{2}Cl_{2}$를 이용한 실리콘 증착은 $675^{\circ}C$에서 열분해가 잘 이루어지지 않고 HCl의 첨가에 의한 식각반응이 동시에 진행되어 실리콘 기판에서도 증착이 진행되지 않으나 $700^{\circ}C$ 이상에서는 HCI을 첨가한 경우에 한해서 선택성이 유지되면서 실리콘의 성장이 이루어졌다, 반면 실리콘-게르마늄막은 실리콘에 비해 열분해 온도가 낮고 GeO를 형성하여 잠입시간을 지연하는 효과가 있는 게르마늄의 특성으로 인해 선택성이나 증착속도 모두에서 유리하였으나 실리사이드 공정시에 표면으로 게르마늄이 석출되는 현상 등의 저항성분이 크게 작용하여 실리콘-게르마늄막 만으로는 외부 베이스에의 적용은 적절하지 않았다. 그러나 실리콘막을 실리콘-게르마늄막 위에 Cap 층으로 증착하거나 실리콘막 만으로 외부 베이스에 선택적으로 증착하여 베이스의 저항을 70% 가량 감소시킬 수 있었다.

• Journal of Aquaculture
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• v.21 no.2
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• pp.111-122
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• 2008

This study was conducted to assess the usefulness of the temperature characteristics of the tidal flat sediments during low tide as a environmental factor, and burrowing behaviour, fatness, total hemocyte counts(THCs) and differential hemocyte counts(DHCs) of hard clam Meretrix lusoria as biological activity indices for the management of hard clam farms located in Taean(Chungnam province) and Gimje(Jeonbuk province) tidal flat in Korea. Temperature ranges of the sediment at 1cm depth during spring(March to May) and summer(June to August) in Taean(where the exposure time was about $5.5{\sim}6$ hours during low tide) were $8.7{\sim}26.8^{\circ}C\;and\;27.6{\sim}32.8^{\circ}C$, respectively. Even though there was no significant difference(P>0.05), temperatures of the surface sediment where submerged with remained seawater were generally higher than that of uncovered with seawater. Burrowing depths of normally digged hard clams were 0.9{\sim}3.6cm from March to October, 2002. In the field experiment performed at Taean farming ground covered with seawater, burrowing times of the clams under natural water temperatures were $41.6{\pm}10minutes$ in February and $5.4{\pm}1.3minutes$ in August, respectively, and these were influenced by water temperatures. Fatness of hard clams began to decrease from May(at Taean tidal flat) and June(at Gimje tidal flat), showed the lowest level in August and increased again from September. Total hemocytes counts in the hemolymph of the hard clams were decreased to the lowest level in July($24.7{\times}10^4cells/mL$, at Taean tidal flat) and August($28.2{\times}10^4cells/mL$, at Gimje tidal flat), and significantly increased again from September(at Taean tidal flat, P<0.01) and October(at Gimje tidal flat, P<0.001), respectively. We observed three types of hemocytes from the hemolymph of hard clams according to whether hemocytes retain the granules or not and the size of the granules. As a results, we could found that periodical monitoring of the sediment temperatures, clam burrowing behaviour and hemocyte parameters were very helpful for the management of hard clam farming.

• Journal of Aquaculture
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• v.16 no.1
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• pp.24-30
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• 2003

Studies of the seed production of Urechis unicinctus were conducted under the laboratory conditions to obtain some information for the U.unicinitus culture. The experiment included developmental studies of the egg development, larval culture, sediment preference and growth of young U.unicinctus. The experiment were conducted from March to August, 2000. The adults of U.unicinctus collected in Namhae-do, Korea. The developments of the fertilized eggs were observed under a light-microscope at intervals of one hour after containing with density of one individual per 1 $m\ell$. The larvae were fed with Phaeodactylum tricornutum cultured at the laboratory. The concentration of the phytoplankton for the feed was 30,000 cells per individual larva. With progress of development, the food concentration was gradually increased, up to 10,000 cells per individual for the young U.unicinctus. Trochophore larvae appeared on the 68 hours after hatching. On the 32 days after hatching, over 50% of fertilized eggs developed into young U.unicinctus. In order to investigate the effect of sediment on the growth and burrowing of U.unicinctus, the young worms were reared in tanks with different grain sizes. The highest value of sediment preference and survival rate of U.unicinctus was shown in the mixture sediment group with below 0.10 mm, 1.01∼12.00 mm, over 3.01 mm and shell. The lowest value in both sediment preference and survival rate of U.unicinctus was observed in 1.0l∼2.00 mm grain size.

• Korean journal of applied entomology
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• v.47 no.1
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• pp.9-15
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• 2008

This study was conducted to investigate the seasonal occurrence of chestnut weevil, Curculio sikkimensis. The chestnuts infected by the weevils were collected from Gongju, Buyeo, and Cheongyang in Chungnam Province, Republic of Korea. Investigation was focus on the escape period of chestnut weevil larvae from the fruits, invading time and vertical distribution in soil, survival rates of larvae during overwintering, emergence period, emergence rate, and sex ratio and longevity of adults. For precocious species, larvae escaped the chestnut from the mid-September to the early-October, middle species and slow species, were escaped from the late-September to the mid-October and from the early-October to the mid-November. After escaping from the chestnut fruits all of the larvae burrowed into the soil within 35 minutes. Overwintering larvae inhabited in the range of $0{\sim}48cm$ from the soil surface and highly distributed in the range of $18{\sim}36cm$. The 74.1 % of wintering chamber were distributed within $18{\sim}36cm$ from the surface. Survival rates observed were 38.0% in 1st year, 16.0% in 2nd years, and 2% in 3rd years, respectively. Seasonal occurrence period of C. sikkimensis was from the early-Aug. to early-Oct. and the optimal occurrence period was the early and mid-Sept. Emergence rate decreased to 8.4% in 1st year, 3.6% in 2nd years, and 0.8% in 3rd years, respectively. Sex ratio was showed in the range of 0.51-0.55. It is female biased ratio. Longevity of adults was 9.9 days for female and 8.9 days for male.

• Journal of Bio-Environment Control
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• v.16 no.3
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• pp.210-216
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• 2007

A study was conducted to find mechanism and spray characteristics of a mini-sprinkler with downward spray to develop a new design type to be able to prevent drop water. The experiments were executed in a plastic greenhouse to minimize the effect of the wind. Data was collected at five different operation pressures and at 4 different raiser heights. Spray characteristics of the sprinkler such as effective radius, effective area, mean application depth, absolute maximum application depth, effective maximum application depth and coefficient of variation were determined. In order to analyze the mechanism and packing supporter of sprinkler, the numerical simulation using ABAQUS was performed. The optimum pressure for preventing drop water was determined.

• Korea journal of population studies
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• v.30 no.2
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• pp.71-95
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• 2007

This paper attempts to identify the principle of family succession and family patterns of yangban in the late Chosun period through an analysis of male adaptation cases found in family registration records. The primary source of analysis is the family registration documents of Uiseong Kim's from the late 17th century to the early 20th century. As a result, it is found that there is a substantial change in the patterns of family from the early and mid Chosun period to the late Chosun period. The change is the strengthening of the principle of patriarchy succession through male adoption. Looking at the data as a whole, the average number of household members is increased and the membership of kinship also expanded. In contrast to the family patterns of the early Chosun period, not only the patterns of Uiseong Kim's family are predominately immediate family or collateral family but also the majority is extended family in the 18th and 19th centuries. The male adoption cases recorded in Uiseong Kim's family registration documents take up 33.8% of the male adoption cases in the entire family registration documents. This goes to show that the strengthening of the principle of primogeniture succession at a time when child mortality rate is very high resulted in the increase of male adoption. In conclusion, the late Chosun society was a society where the seat of primogeniture was much more important than immediate hereditary members in the family succession.