• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1993년도 봄 학술발표회 논문집
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• pp.40-45
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• 1993

Due to the recent shortage of river sand resulting from a rapid growth of concrete construction, sea sand and pit sand are increasingly used in stead. It is , however, well noted that non-washed sea sand used in reinforced concrete causes to corrode reinforcing steel and to incur cracks in concrete, and thus eventually result in damage to concrete. Moreover, many sources of pit sand in our country are randomly used without experimental research for its applicability to concrete construction. The purpose of this research to activate the usage of pit sand and sea sand for concrete construction to solve the recent shortage of river sand. Followings have been experimentally investigated : 1)Physical properties of pit sand and sea sand, 2)Compressive strength of mortar on the weight of pit sand passing through No.200 sieve, 3) Compressive strength of mortar on the chloride content of sea sand, 4) Compressive strengths of concrete using pit sand and sea sand, respectively, 5)Corrosion propagatio in reinforcing steel on the chloride concent, of sea sand, and 6)etc.

• 한국동물학회지
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• 제39권1호
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• pp.115-121
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• 1996

임신중기에서 발기에 이르는 흰쥐의 태반에서 Placental Lactogen I (PL-I), II 그리고 Pit-1 의 유전자 발현 변화를 Northern blot hybridization으로 조사하였다. 그 결과, 임신시기에 따라 PL-I과 PL-II의 mRNA 양과 크기에 변화가 나타났다. 이들 유전자 발현에 미치는 에스트로겐의 영향을 조사하기 위하여, 임신 14일째 쥐의 난소를 제거하고(OVX), 이후 매일 에스트로겐을 투여한 후 (OVX+E), 임신 18일째 태반을 회수하여 PL-I, II 그리고 Pit-1의 유전자 발현을 Northern blot hybridization으로 조사하였다. OVX 군의 경우, PL-I의 mRNA 크기는 1 kb에서 1.3 kb로 PL-II의 mRNA는 0.6kb에서 1 kb로 변화하였다. OVX+E 군에서는 PL-I과 PL-II의 mRNA가 정상대조군과 같은 상태로 환원하였다. 정상대조군에 비하여 OVX와 OVX+E 군에서 PL-I과 PL-II의 mRNA 크기에는 영향을 미치지 못한 반면, mRNA 양은 난소제거시 감소하였다가, 에스트로겐을 투여하면, 부분적으로 회복되는 경향을 보였다. 이러한 본 실험의결과는 에스트로겐이 PL-I과 PL-II의 RNA splicing이나 polyadenylation 등을 포함한 유전자 발현에 영향을 미치며, Pit-1이 이 과정에 개입하는 것을 시사하는 것이다.

• Journal of Astronomy and Space Sciences
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• 제32권2호
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• pp.113-120
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• 2015

When humans explore the Moon, lunar caves will be an ideal base to provide a shelter from the hazards of radiation, meteorite impact, and extreme diurnal temperature differences. In order to ascertain the existence of caves on the Moon, it is best to visit the Moon in person. The Google Lunar X Prize(GLXP) competition started recently to attempt lunar exploration missions. Ones of those groups competing, plan to land on a pit of Lacus Mortis and determine the existence of a cave inside this pit. In this pit, there is a ramp from the entrance down to the inside of the pit, which enables a rover to approach the inner region of the pit. In this study, under the assumption of the existence of a cave in this pit, a 3D model was developed based on the optical image data. Since this model simulates the actual terrain, the rendering of the model agrees well with the image data. Furthermore, the 3D printing of this model will enable more rigorous investigations and also could be used to publicize lunar exploration missions with ease.

• Asian-Australasian Journal of Animal Sciences
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• 제14권12호
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• pp.1659-1664
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• 2001

Several studies have been done regarding carcass traits and growth in pigs. Recently, these have progressed to examine increases in economic traits, including meat quality and meat quantity, by using candidate genes. One of them is the pituitary-specific protein PIT-1, a member of the POU (Pit-Oct-Unc) family of transcription factors playing an important regulatory role in developmental processes. In addition, muscle development is known to be regulated in part by growth factors and cytokines locally produced. Therefore, studies were performed to analyze PIT-1 genotypes and serum cytokines (IGF-I, IGF-II, TGF-${\beta}1$, EGF, cortisol, DHEA-S, IL-2, and IL-6) in castrated male pigs for their possible involvement in the development of carcass traits. The genotypes of PIT-1 gene were analyzed by PCR-RFLP with MspI restriction enzyme. But, only CD and DD genotypes, not CC genotype, have been detected. Based on PIT-1 genotyping, a significant difference in EGF expression beween CD type (78.8 ng/ml) and DD type (46.0 ng/ml) was detected (p<0.05), whereas other cytokines did not show any statistical significance depending on PIT-1 genotypes. Collectively, these results suggest the possibility that EGF could affect the formation of carcass traits.

• 한국해양공학회지
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• 제2권2호
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• pp.78-86
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• 1988

In order to investigate the corrosion pit occurrence and growth characteristic of M.E.F.(martensite encapsulated islands of ferrite) dual phase steel was made with a suitable heat treatment of raw material(SS41), a corrosion fatigue test was performed under rotary bending in the salt solution having a concentration from 0.01 wt percent to 3.5 wt percent. The fatigue strength of dual phase steel was remarkably decreased with an increase in concentration of salt solution; approximately from 63% to 80% in case of dual phase steel and from 40% to 71% in case of raw material. Corrosion pit occurred in the martensite phase and fatigue cracks from corrosion pits were selectively propagated in martensite phases. In the observation of corrosion pits at the origin of fatigue cracks, it had been found that corrosion pits were grown into hemispherical pits and a/c(the surface diameter, 2c and the depth, a of corrosion pit)was about 1.0-1.5regardless of the variation of salt solution concentration. The difference of corrosion pit depth growth rate was increased with an increase in concentration of salt solution according to an increase in stress level.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.229-236
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• 2002

In this paper, a new novel technique of seismic survey is introduced to estimate the continuity of inclined pits filled with water, It was assumed that the pits would be connected to an abandoned railway tunnel that might be constructed in the past. Thus, detection of pit end was needed for the design of a new highway tunnel(Yukshimreong tunnel) that was likely to be met with a pit. In the beginning of exploration, no reliable, cost effective method was available. Hence, focus of interest moved toward the high impedance contrast(reflection coefficient k∼0.8) between water and rock. In this special model of sequence rock-water-rock, total reflection occurs and the seismic energy, when it is generated in the pit water, is nearly confined to the pit so that seismic waves can propagate much further within the pit. As a matter of convenience, this is called“tunnel channel wave”. With these considerations in mind, seismic detonator(2g) was used as a source at the entrance of pit, whereas hydrophone chain(hydrophone interval=1m) was placed on the bottom of pit. With this appropriate source-receiver arrangement, desirable down-going and up-going waves could be observed that will help conform the continuity of pits. After about one year, it was ascertained that the inclined pit of interest was just nearby crossed with the newly excavated tunnel, as it was predicted.

• Current Applied Physics
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• 제18권12호
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• pp.1558-1563
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• 2018

We demonstrate improved surface pit and phase separation in thick InGaN grown on a GaN/Si (111) substrate, using plasma-assisted molecular beam epitaxy with an indium modulation technique. The formation of surface pit and compositional inhomogeneity in the InGaN epilayer are investigated using atomic force microscopy, scanning electron microscopy and temperature-dependent photoluminescence. Indium elemental mapping directly reveals that poor compositional homogeneity occurs near the pits. The indium-modulation epitaxy of InGaN minimizes the surface indium segregation, leading to the reduction in pit density and size. The phase separation in InGaN with a higher pit density is significantly suppressed, suggesting that the pit formation and the phase separation are correlated. We propose an indium migration model for the correlation between surface pit and phase separation in InGaN.

• 한국멀티미디어학회논문지
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• 제16권8호
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• pp.954-961
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• 2013

미래 인터넷 기술 중 하나인 콘텐츠 중심 네트워킹(CCN)은 네트워크 성능 향상을 위하여 네트워크 노드들이 수신된 콘텐츠를 임시 저장하고, 해당 콘텐츠에 대한 요청을 수신하면 임시 저장된 콘텐츠를 이용하여 네트워크 노드가 이를 직접 처리한다. 또한, CCN은 IP 주소와 같은 호스트 Identity 대신 계층화된 콘텐츠 이름을 이용하여 패킷을 전송하고, 요청자 프라이버시 보호를 위하여 요청 메시지는 요청자 정보를 포함하지 않기 때문에 콘텐츠 제공자와 네트워크 노드들은 실제 요청자를 식별할 수 없다. 수신된 콘텐츠를 요청자에게 전송하기 위하여 네트워크 노드는 PIT(Pending Interest Table)에 요청 메시지와 해당 요청 메시지의 유입경로 정보를 기록하고, 콘텐츠를 수신하면 기록된 PIT 정보를 이용하여 해당 콘텐츠를 요청자에게 전송한다. 만약 PIT 저장 공간이 고갈되면, 콘텐츠 요청 메시지와 수신된 콘텐츠를 정상적으로 처리할 수 없다. 그러므로 안전한 CCN 구현을 위해서는 PIT 저장 공간 고갈을 목적으로 하는 공격의 탐지와 대응이 필요하다. 본 논문에서는 PIT 저장 공간에 대한 공격 탐지 및 대응을 위하여 공격 메시지 유입 경로에 따른 공격탐지/제어 방안을 제안하고, 공격 제어를 위한 메시지 구조를 함께 제안한다. 또한, 제안된 방식을 시뮬레이션을 통하여 그 성능을 평가 한다.

• 생태와환경
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• 제42권1호
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• pp.134-138
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• 2009

국내에 서식하는 5종의 담수 잉어과 어류(참갈겨니, 피라미, 누치, 납자루, 끄리) 173개체를 대상으로 PIT 태그를 체내 삽입 후, 30일 간 매일 생존율을 파악하여 태그의 적용성과 활용 가능성을 타진하였다. 생존율 테스트 결과, 참갈겨니가 가장 높은 생존율을, 피라미가 가장 낮은 생존율을 보였으며, 전반적으로 개체의 전장이 길수록 생존 기간도 긴 것으로 나타났다. 초기 사망률은 외과적 수술과정에서 내부 장기의 손상 등과 관련이 있는 것으로 보였다. 본 실험결과 피라미를 제외한 국내에 서식하고 있는 소형 담수어류에도 PIT 태그 적용이 가능할 것으로 사료되며, 종에 따라 다소 차이는 있으나, PIT 태그의 야외현장 적용을 위해서는 전장 150mm의 개체를 사용하는 것이 적절할 것으로 판단된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권3호
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• pp.93-108
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• 2013

This study is aimed to prepare the effective detail survey methods(Phase II) of abandoned metal mines through the contamination assessment for mine types and facilities in the abandoned metal mine areas. The study sites of 12 abandoned mines are located in Gyeonggi-do and Gangwon-do and those were chosen among 310 sites that the Phase II survey was conducted from 2007 to 2009 after considering the results of Phase I for abandoned mines scattered all over the country. 12 study sites were classified into four types; Type I sites only have pit mouth. Type II sites have pit mouth and mine-waste field. Type III sites have pit mouth and tailing sorting field. Type IV sites have pit mouth, tailing sorting field and concentrator(s). In forest land, paddy soil and farm land of Type I, As and Cd were showed average concentration, and Cu and Pb were high on the pit mouth area in one mines where the pit mouth was developed within 500 m. In the mines of Type II, Cu and Pb were showed average concentration too, but As and Cd were slightly high in pit mouth and mine-waste field. The mines of Type III which had grinding particle process through physical separation milling or hitting showed similar tendency with Type II. However, mines of Type IV pit mouth, mine-waste field and showed various results depending on defining the contamination sources. For example, if contamination source was pit mouth, the mixed results of Type I, II, II were showed. In tailing sorting field which was regarded as the most important source and having high mobility, however, if there were no facilities or it was difficult to access directly, field sampling was missed occasionally during phase I and phase II survey. For that reason, the assessment for tailing sorting field is missed and it leads to completely different results. In the areas of Type I mines, the concentration of heavy metals exceeded precautionary standards of soil contamination or not within 1,000 meters of pit mouth. Nickel(Ni) was the largest factor of the heavy metal contamination in this type. The heavy metals except Arsenic(As) were shown high levels of concentration in Type II areas, where pit mouth and mine-waste field were operated for making powder in upriver region; therefore, to the areas in the vicinity of midstream and downstream, the high content of heavy metals were shown. The tendency of high level of heavy metals and toxic materials contained in flotation agent used during sorting process were found in soil around sorting and tailing field. In the abandoned-pit-mouth area, drygrinding area and tailing sorting field area, the content of Cupper(Cu) and Zinc(Zn) were higher than other areas. Also, the contaminated area were larger than mine reclamation area(2,000 m) and the location of tailing sorting field was one of the important factors to estimate contaminated area.