• 한국발생생물학회지:발생과생식
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• 제22권1호
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• pp.1-8
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• 2018

The annual reproductive cycle of the Korean endemic slender catfish, Silurus microdorsalis, was examined histologically regarding water temperature and day length of habitat, gonadosomatic index (GSI), and development characteristics of female and male gonads. The maximum GSI value was found in May, $1.23{\pm}0.33$ and $11.77{\pm}3.23$ for male and female respectively (habitat water temperature $21.5^{\circ}C/13.59hr$ day length). On the other hand, the minimal level was $0.63{\pm}0.10$ in July ($26.5^{\circ}C/14.17$) for male and $1.36{\pm}0.08$ in October ($20^{\circ}C/11.2hr$) for female. We compared and calculated the stages of testis and ovary development process in order to determine the germ cell development characteristics and the reproductive cycle. According to results, we classified the annual reproductive cycle of the slender catfish into five stages: Growing phase (December-February), Mature phase (March-April), Ripe and spawning phase / Releasing phase in male (May-June), Degenerative phase (July-August), and Resting phase (September-November).

• 대한건축학회논문집:구조계
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• 제34권4호
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• pp.59-64
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• 2018

Construction schedule acceleration due to unreasonable construction planning frequently leads to construction accidents. In order to avoid such inevitable acceleration and to ensure safety in construction sites, there is a need for objective standards to determine appropriate construction duration for each construction process earlier in the process. In order to achieve the goal, intensive experts interviews were firstly conducted to identify candidate drivers affecting construction schedule of road tunnel excavation works. Then, a total of 34 field data was collected from on-going sites to analyze. It was found that actual excavation length per one day on site is varied mostly by Rock Mass Rating(RMR) types from various statistical analyses. Therefore an one-way table of excavation length per a day by RMR types were presented in a form of percentile. The results will help industry experts determine the most appropriate construction schedule for the works, which eventually lead to a zero accident site in many ways.

• 한국어류학회지
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• 제27권2호
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• pp.95-103
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• 2015

우리나라 고유 담수어류 줄종개 Cobitis tetralineata의 난발생 및 초기생활사를 연구하기 위하여 2013년 6월 섬진강 상류인 전북 순창군 복흥면 정산리에서 족대를 이용하여 친어를 채집하여 실험하였다. 채집된 성숙한 친어는 복강에 Ovaprim을 주사하여 12시간 경과 후 복부압박법으로 채란하고 건식법으로 인공수정 시켰다. 산란된 성숙란은 약한 점착성을 띤회색의 분리침성난으로 난경은 $1.04{\pm}0.03mm$이고 산란수는 $2,646{\pm}916$개였다. 수온 $25^{\circ}C$에서 수정 후 56시간 만에 부화 하였으며, 크기는 전장 $4.6{\pm}0.11mm$이었다. 부화 5일 후에 전장 $6.8{\pm}0.28mm$로 난황이 모두 흡수되어 후기자어로 이행하였으며, 25일 후에는 전장 $9.8{\pm}0.50mm$로 지느러미 기조가 모두 정수로 되어 치어기로 이행하였다. 부화 후 100일 후에는 전장 $34.7{\pm}5.77mm$로 4줄의 Gambetta's zone이 완성되고 외형은 성어와 비교적 유사하였다.

• 한국어류학회지
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• 제31권1호
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• pp.30-38
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• 2019

한국고유종 점줄종개 Cobitis nalbanti의 난발생 및 초기생활사를 조사하였다. 성어는 2011년 6월 영산강 상류인 전남 장성군 북하면 성암리에서 족대를 이용하여 채집하였다. 채집된 성숙한 친어는 복강에 Ovaprim을 주사하고, 12시간 경과 후 복부압박법으로 채란하고 건식법으로 인공수정시켰다. 산란된 성숙란은 약한 점착성을 띤 밝은 황색의 분리침성난으로 난경은 $0.99{\pm}0.03mm$이고 산란수는 $1,527{\pm}410$개였다. 수온 $25^{\circ}C$에서 수정 후 52시간 후에 50%가 부화하였으며, 크기는 전장 $4.2{\pm}0.22mm$였다. 부화 5일 후에 전장 $6.0{\pm}0.34mm$로 난황이 모두 흡수되어 후기자어로 이행하였으며, 15일 후에는 전장 $10.8{\pm}0.45mm$로 지느러미 기조가 모두 정수로 되어 치어기로 이행하였다. 부화 후 100일 후에는 전장 $41.1{\pm}2.95mm$로 4개의 점줄로 이루어진 Gambetta's zone이 뚜렷하고 외형은 성어와 비교적 유사하였다.

• 해양환경안전학회지
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• 제20권5호
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• pp.461-467
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• 2014

가시망둑(1.80~10.01 cm TL)의 성장과 생산량에 대한 연구를 동대만 잘피밭에서 2006년도에 실시하였다. 가시망둑 시료는 소형 빔트롤로 총 702개체를 채집하였다. 본 연구 결과, 가시망둑에 대한 전장(TL)의 성장식은 $TL=0.0539d^{0.9105}$, 전장과 체중의 관계식은 $W=0.0079TL^3.1103$이었다. 가시망둑의 단위면적당 밀도, 생체량, 일일생산량, 연간생산량은 각각 $0.06{\pm}0.062/m^2$, $0.10{\pm}0.144g/m^2$, $0.0005{\pm}0.0006g\;AFDW/m^2/day$, $0.1833g\;AFDW/m^2/year$이었으며, P/B의 비율은 1.813이었다. 가시망둑 생산량은 생체량의 높았던 5월과 7월 9월에 가장 높았으며(0.0029, 0.0031, $0.0019g\;AFDW/m^2/day$), 생체량이 낮았던 12월에 가장 낮았다($0.00004g\;AFDW/m^2/day$). 가시망둑의 월별 생산량의 변화에서 양의 상관관계를 보인 것은 생체량과 수온이었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권3호
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• pp.205-217
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• 2005

Distraction osteogenesis is a technique of lengthening bone including soft tissue by gradual separation of surgically divided bone surfaces. Although the biomechanical, histological, and ultrastructural changes associated with distraction osteogenesis have been widely described, the molecular mechanisms governing the formation of new bone in distracted bone segments remain largely unclear. However, such information has significant clinical implications because it may enable targeted therapeutic manipulations designed to accelerate osseous regeneration. The purpose of this study was to evaluate the expression of TGF-$\beta$1, IGF-I and bFGF in distraction osteogenesis according to different distraction rates in a rabbit's mandible. When twenty-four adult rabbits underwent open osteotomy between the premolar and mental foramen, an external bilateral distraction device was applied. Latency was allowed for five days before distraction. Three different distraction rates were 0.7 mm/day (A, n=8), 1.4 mm/day (B, n=8) and 2.4 mm/day (C, n=8). The distraction device was activated with the same distraction rhythms of twice a day until 4.9 mm (A & B group) and 8.4 mm (C group) length gains was achieved. The animals were sacrificed at postoperative 3, 7, 14 and 28 days. The bony specimens were stained with H&E for histologic examination, and RT-PCR analysis was done for the identification of the expression of TGF-$\beta$1, IGF-I and bFGF. The results obtained from this study were as follows : The 0.7 mm/day and 1.4 mm/day distraction rate groups were shown to improve regenerative bone formation on radiographic and histologic examination. Also, TGF-$\beta$1, IGF-I and bFGF expression increased in the 0.7 mm/day and 1.4 mm/day distraction rate groups. But the 2.4 mm/day distraction rate group specimen was different with adjacent normal bone and hardly expressed of growth factors. These findings suggest that improved new bone formation in the 0.7 mm/day and 1.4 mm/day distraction rates is associated with enhanced expression of TGF-$\beta$1, IGF-I and bFGF by mechanical tension stress. Additionally, the 0.7 mm/day and 1.4 mm/day distraction rate groups were significantly different from the 2.4 mm/day distraction rate group in the expression of growth factors. According to the above results, it seems possible to apply a distraction rate of up to 1.4 mm/day a day in rabbit's mandible. And further studies are needed to evaluate growth factors of TGF-$\beta$1 and IGF-I, which are excellent in expression.

• 한국대기환경학회지
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• 제29권6호
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• pp.734-744
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• 2013

In this study, the telematics device was installed on the car (OBD-II) to collect the information on the operation conditions from each sample vehicle. Based on the information the domestic driving pattern was analysed and the ratio of cold start length was estimated. As a result of analysis for driving pattern, we found a difference in the frequency of driving on the hourly or seasonal basis. Then, the driving pattern of the rush hours, weekdays, and weekends could be derived. Also, from the study, an average of 2.22 times per day occurred in a single trip and average driving distance for the trip was 15.72 km. In addition, the proportion of cold start length was analyzed to be 16.11%. The seasonal cold start length has big difference from season to season (Winter 26.63%, Summer 8.22%, Intermediate 12.65%). There was an inverse relationship between the outside temperature and ratio of cold start length. In order to improve the accuracy of the cold emission estimation, it is necessary to apply domestic ratio of cold start length that driving pattern and temperature in Korea is reflected.

• 한국양식학회지
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• 제12권4호
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• pp.255-266
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• 1999

The early development, growth, and morphological changes of Tiger puffer Takifugu rubripes are described on the basis of a seres of a series of reared specimens. Detailed o수 the early developmental stages are illusrtated withe special reference to morphological transformation. Egg and sperm of puffer fish Takifugu rubripes were obtained from mature adults under natural conditions, ferilized artificially and incubated in the laboratory. The incubation period of fertilizd eggs was 160 to 180 hours at a temperature of $15.1~ 18.0^{\circ}C$. Larvae were fed successively with rotifer, Artemia nauplii and artificial food for 90 days. The mean total length of newly-hatched larvae was about 2.8mm. Mouth opening occurred on the 1- day yolk-sac larvae and initial feeding was observed on th 4-5 days after hatching . The morphological transitions from the larvae to juvenile and juvenile and juvenile to young stages occurred when fish reached about 10mm in total length(about 30 days after hatching) and about 32mm in total length(about 60days after hatching) , respectively. The coefficient of variation in total length distribution increased with growth. Following the appearance of its peak at the size of about 18mm in total length, the coefficient value declined. Many changes in proportion of the body parts to total length were observed at about 9~10mm and 30~33mm in total length, corresponding to the transformations from larvae to juvenile and from juvenile to young, respectively. Also one big morphological change was observed at about 18mm in total length that divide the juvenile stage into two sub-stages.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.607-612
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• 2002

In road pavements, it is known that cement concrete pavement has superior durability, safety compared. But in repairing pavement, cement concrete pavement is not usually applied because of the length of time while the road is interrupted when using Ordinary and Rapid-hardening Portland Cement. And Super High Early Strength Cement and Ultra Super High Early Strength Cement are not favorable for ready mixed concrete because of rapid setting time, high slump loss and other restrictions. We developed special cement developing 1 day strength of over 30.0N/mm$^2$ to open the road within 1 day and workable time is maintained over 1 hour so that it can be used as ready mixed concrete. We performed experimental overlay construction with the cement and evaluated the mechanical property and the durability. At curing temperature of 8-l8$^{\circ}C$,the flexural strength was 6.4N/mm$^2$at 1 day, so that the road can be open to traffic within 1 day. In durability test, the hardened concrete showed higher durability than Portland cement concrete.

• 천문학회보
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• 제42권2호
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• pp.70.1-70.1
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• 2017

We reexamine the Goryeosa (History of the Goryeo Dynasty, A.D. 918-1392) account that Halley's Comet was seen during the daytime on September 9, 1222. To verify whether the referenced "daytime" refers to twilight or daylight (i.e., when the Sun is above horizon), we determine the absolute magnitude and heliocentric power-law exponent for Halley's Comet using observations made around the perihelion in 1986 and a formula considering the brightness enhancement by forward-scattering. We then apply the results to estimate the light curve of Halley's Comet in the 1222 event and find that the total visible magnitude could reach a maximum of -1.7 on September 8, one day before the Goryeosa's account. Therefore, we think that Halley's Comet with a coma of -1.7 mag and tail-length of about $20^{\circ}$ was actually observed during the day on September 9 because the observational conditions on that day were so good that Venus was visible in daylight. Furthermore, we think that the event might have been witnessed in the morning sky because the contents of Venus's culmination (occurred around September 9.07 TT) continue on the same day account.