• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2003년도 제3회 국제심포지움 및 학술대회
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• pp.75-75
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• 2003

Transition of the resting primordial follicle to the growing primary follicle is a critical process for female reproduction, but its mechanism is poorly understood. The present study was conducted to investigate gene expression profile at the primordial-primary follicle transition process. We isolated total RNA of female mouse ovary at day1 (contains only primordial follicles) and day5 (contains primordial and primary follicles) and synthesized cDNA using annealing control primers (ACP; Seegene, Inc., Seoul, Korea). ACP provides annealing specificity and sensitivity to the template and allows to identify only authentic differentially expressed genes (DEGs). We used total 80 ACPs for PCR, observed PCR products on 2% agarose gel, cloned 42 DEGs using TOPO TA cloning vector, sequenced, and analyzed by BLAST search. Sequences of 34 clones significantly matched database entries while 4 clones were novel and 4 clones were EST. Two of 34 genes were specifically expressed only in day 5 ovaries (Sui1-rs1, Apg3p/Aut1p-like), and rest of 32 genes were expressed in both stages but were differential in amount. Differential expression was confirmed using semiquantitative RT-PCR, and there was no false positive. Anx11 and Pepp2-pending were highly expressed genes in day1-, while BPOZ, Ches1, Kcmf1, NHE3, Nid2, Ninj1, SENP3 and Survivin were highly expressed genes in day5-ovary. List of genes would provide insight for further study of mechanism regulating primordial-primary follicle transition.

• Journal of Photoscience
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• 제7권1호
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• pp.15-19
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• 2000

The photochemical reaction mechanism has been investigated for methanol insertion into the p-substituted phenylketo carbenes. The triplet spin state of phenyl koto carbene is stabilized by the neighbored carbonyl electrons. When the phenylketo carbene reacts with methanol, the ylied intermediate is formed, then moves to the activated transition state.

• Bulletin of the Korean Chemical Society
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• 제19권12호
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• pp.1334-1336
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• 1998

Kinetic studies are carried out on the reactions of 2-chloro-2-propen-1-yl arenesulfonates with anilines and N,N-dimethylanilines in acetonitrilile at 45.0 ℃. The 2-chloro substituent is found to deactive the allyl moiety with considerable decrease in the rates. The sign and magnitude of the cross-interaction constant (ρxz 0.3) and the inverse secondary kinetic isotope effect (kH/kD 0.92) support an SN2 mechanism with a relatively tight transition state. The possibility of an SN2' mechanism can be safely precluded based on the ρxz values observed.

• 한국터널지하공간학회 논문집
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• 제14권6호
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• pp.653-666
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• 2012

본 연구는 터널의 단면변화구간에서 발생한 손상 미케니즘에 대하여 이루어졌다. 이를 위해 단면변화 구간을 대상으로 다양한 현장조사 및 시험을 실시하였으며, 이를 바탕으로 2차원 및 3차원 수치해석을 수행하였다. 현장조사 및 시험 결과, 슬래브 손상에 대한 직접적인 원인을 찾을 수 없었으며, 2차원 수치해석을 수행한 결과 기준 안전율(1.0)을 만족하는 것으로 분석되었다. 추가로 수행한 3차원 수치해석 결과, 기둥 간격의 변화에 따라 슬래브 휨응력 변화를 전달시키지 못해 손상이 발생한 것으로 분석되었다. 보강을 위해 터널내 기둥을 추가하는 방안을 적용하였으며 그 결과, 상부 슬래브 비틀림 형상이 완화되어 보강 효과를 확인할 수 있었다. 단면 변화 구간의 경우 2차원 뿐만 아니라, 3차원으로 영향범위를 고려하여 설계에 반영한다면, 합리적이고 안정적으로 건설 및 유지관리가 가능할 것으로 판단된다. 추후에는 개착터널내 단면변화 구간에서 구조물에 영향을 최소화할 수 있는 보강방안에 대해 연구를 계속하고자 한다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.701-705
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• 2002

본 논문에서는 6TALK (IPv6 TrAansLator of Krv6) 프로젝트의 구현에 대한 내용과, 이를 이용하여 IPv6 망이 기존의 IPv4망이나, 다른 IPv6망과 자연스럽게 연동할 수 있는 시나리오에 관해 기술한다. 이미 잘 알려진 바와 같이 현재의 IPv4 인터넷은 인터넷 사용자의 폭발적인 급증과 더불어 한계를 맞이하고 있다. 이를 극복하기 위해 제안된 IPv6는 현재 여러 기술적인 표준화와 실험 망에서의 테스트 과정을 마무리 짓고 있는 단계이다. 앞으로의 IPv6의 보급에 있어 가장 중요한 과정은 기존에 널리 존재하고 있는 IPv4망과 자연스럽게 공존하며 그 적용 범위를 넓혀갈 수 있도록 하는 전이 기술을 개발, 보급하는 일이다 이를 위해서 IETF에서는 NGTrans라는 WG을 별도로 만들어 IPv6로의 전환에 관련된 기술들을 표준화하고 있다. 현재 전 세계적으로 다양한 IPv6 관련 전환기술 프로젝트들이 진행되고 있으며, 본 논문에서 소개하는 6TALK 프로젝트도 NGTrans WG에서 소개하는 기술들을 바탕으로 망의 구성에 따라 IPv4망과 IPv6망이 자연스럽게 공존할 수 있도록 하는 솔루션들을 제공하는 것을 최종 목표로 하는 프로젝트이다. NGTrans WG에서 제안한 전환기술은 듀얼스택, 터널링, 변환기 등과 같은 기본 기술들과, 이 기본 기술을 확장 응용한 기술들로 이루어져 있다. 6TALK는 이러한 전환기술들을 복합적으로 사용하며, 네트워크의 가장자리(edge)에 존재하는 IPv6망이 기존 IPv4망이나, IPv4 망을 사이에 두고 존재하는 IPv6망과 연동할 수 있도록 하는 기능을 제공한다. 6TALK은 전이기술로 NAT-PT/SIIT와 몇몇 응용레벨 프로토콜에 대한 ALG, 구현환경으로는 커널 2.4.18버전이 탑재된 리눅스를 이용하고 있다.d it apply a electronic cash system. In particularly a proposed electronic cash system have an anonymity control ability which trace a user who make use a electronic cash illegally in association with a trusted center.estigation and explain how our tool can be further enhanced.door playground facilities. On the basis of the site investigation the interview and the indoor education program for physically challenged children the author completed an outside play program. Each item in this program was classified as belonging to either a "sense play" program or and "exercise play" program. Finally, the author designed suitable play equipment for physically challenged children corresponding to each item in the exercise programs in order to research the appropriateness of the equipment to its intended use. This research is the first step. From this point the author expects that sp

• Bulletin of the Korean Chemical Society
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• 제26권12호
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• pp.1953-1961
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• 2005

We have performed high-level quantum mechanical calculation for multiple proton transfer in HOCl + HCl and $H_2O$ + $ClONO_2$ on water clusters, which can be used as a model of the reactions on ice surface in stratospheric clouds. Multiple proton transfer on ice surface plays crucial role in these reactions. The structures of the clusters with 0-3 water molecules and the transition state structures for the multiple proton transfer have been calculated. The energies and barrier heights of the proton transfer were calculated at various levels of theory including multi-coefficient correlated quantum mechanical methods (MCCM) that have recently been developed. The transition state structures and the predicted reaction mechanism depend very much on the level of theory. In particular, the HF level can not correctly predict the TS structure and barrier heights, so the electron correlation should be considered appropriately.

• Genomics & Informatics
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• 제12권1호
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• pp.12-20
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• 2014

The epithelial-mesenchymal transition (EMT) is one mechanism by which cells with mesenchymal features can be generated and is a fundamental event in morphogenesis. Recently, invasion and metastasis of cancer cells from the primary tumor are now thought to be initiated by the developmental process termed the EMT, whereby epithelial cells lose cell polarity and cell-cell interactions, and gain mesenchymal phenotypes with increased migratory and invasive properties. The EMT is believed to be an important step in metastasis and is implicated in cancer progression, although the influence of the EMT in clinical specimens has been debated. This review presents the recent results of two cell surface proteins, the functions and underlying mechanisms of which have recently begun to be demonstrated, as novel regulators of the molecular networks that induce the EMT and cancer progression.

• 분석과학
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• 제12권6호
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• pp.465-471
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• 1999

클로로메틸화폴리스틸렌에 디에틸렌트리아민을 선형과 집게형으로 지지시킨 수지를 합성하고 이 수지에 전이금속이 흡착되는 속도를 limited-bath법으로 측정하였다. 이 결과에서 확산계수, 활성화 엔트로피와 활성화 자유에너지를 구하였다. 속도론적 데이터에서 전이금속이 수지에 흡착되는 반응 과정의 속도결정단계는 확산과정임을 알 수 있었다.

• 한국공작기계학회논문집
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• 제15권4호
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• pp.15-21
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• 2006

Recently, atomic force microscope(AFM) with suitable tips is being used for nano fabrication/nanometric machining purposes. In this paper, acoustic emission(AE) was introduced to monitor the nanometric machining of brittle materials(silicon) using AFM. In the experiments, AE responses were sampled, as the tip load was linearly increased(ramped load), to investigate the machining characteristics during a continuous movement. By analyzing the experimental results, it can be concluded that measured AE energy is sensitive to changes in the mechanism of material removal including the ductile-brittle transition during the nanometric machining. The critical depth of cut value for the transition is evaluated and discussed.

• Journal of Ship and Ocean Technology
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• 제8권4호
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• pp.10-16
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• 2004

A response of a swept wing boundary layer to a single free-stream stationary axial vortex of a limited spanwise extent is considered as an example of typical problems that one can find in laminar-turbulent transition research and control. The response is dominated by streamwise velocity perturbations that grow quasi-exponentially downstream. It is shown that the formation of the boundary layer disturbance occurs for the most part close to the leading edge. The disturbance represents itself a wave packet consisted of the waves with characteristics specific for cross-flow instability. However, an admixture of growing disturbances whose origin can be attributed to transient effects and to a distributed receptivity mechanism is also identified.