• Title/Summary/Keyword: 착상 모델

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Behaviors of Frost Formation on a Plate Fin Considering Fin Heat Conduction (휜의 열전도를 고려한 평판 휜에서의 착상 거동)

  • Kim, Jeong-Su
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.38 no.12
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    • pp.51-60
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    • 2009
  • 본 연구에서는 착상 조건 하에서 열교환기 휜의 열전도를 고려하여 휜 표면에서의 착상 거동을 예측하기 위하여 수학적 모델을 제시한다. 이 때, 공기측은 착상 현상에 대한 3차원 유동 변화의 영향을 고려한다. 서리층 두께에 대한 해석 결과는 실험 결과를 최대 10% 오차 내에서 잘 예측한다. 유동에 수직한 방향(z-dir.)의 서리층 두께 성장은 휜의 열전도에 의해 휜 바탕 근처에서 활발하고, 휜 끝으로 갈수록 지수함수적으로 둔화된다. 휜의 열전도를 고려한 경우에 비해 휜의 표면온도가 일정한 조건에서 서리층 두께는 최대 2배, 열전달량은 평군 10% 정도 과대 예측한다. 따라서, 열교환기 휜에서의 착상 거동을 정확하게 예측하기 위해 착상 모델 해석 시 휜의 열전도를 고려해야 한다. 휜의 열전도 고려 유무에 따른 착상 거동의 차이를 보완하기 위해 열전달량에 대한 등가온도를 산출하며, 이를 근거로 무차원 등가 온도 상관식을 도출한다.

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A New Dynamic VRF Heat Hump Simulation Including Frosting and Defrosting Models (착상 및 제상을 포함한 VRF 히트펌프의 동적 수치해석 모델)

  • Park, Noma;Shin, Jeong Seob;Chung, Baik Young;Kim, Byung Soon
    • Transactions of the KSME C: Technology and Education
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    • v.3 no.1
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    • pp.1-13
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    • 2015
  • In this study, a new dynamic VRF-type heat pump simulation model is proposed which incorporates frosting and defrosting models. Toward this end, a simple frosting model based on the perfect analogy, and lumped system based defrost model, are proposed. Then, frosting and defrosting models are incorporated into a dynamic heat pump model which adopts segment-by-segment local heat exchanger model and map-based variable speed compressor model. Thus, the model can naturally represent locally uneven frosting and defrosting on the heat exchanger surface. Developed simulation model is validated against available experimental data to show good agreement within 10% error for capacity and COP. Finally, developed dynamic heat pump model is applied to annual heating season simulation to show that seasonal COP of heat pump is degraded by 7% due to frosting and defrosting.

Effect of Hydrosalpingeal Fluid on the Implantation in-vitro in a Murine Model (생쥐 배아의 체외배양 시 착상과정에 대한 난관수종액의 영향)

  • Jun, Jin-Hyun;Koong, Mi-Kyoung;Lim, Chun-Kyu;Kim, Soo-Kyung;Kang, Inn-Soo
    • Clinical and Experimental Reproductive Medicine
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    • v.27 no.2
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    • pp.159-164
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    • 2000
  • 연구목적:인간의 체외수정 및 배아이식술에서 난관수종을 갖는 환자에서 임신율과 착상률이 감소된다는 보고들이 있지만 이에 대한 명확한 기작은 밝혀지지 않았다. 본 연구에서는 생쥐 배아를 이용한 체외 착상모델에서 인간의 난관수종액(HSF)이 착상과정에 미치는 영향을 알아보고자 하였다. 연구재료 및 방법 난관수종액은 난관수종으로 수술을 받은 8명의 환자로부터 채취하였으며, 실험에 사용하기 전까지 냉동고에 보관하였다. 생쥐의 포배기 배아는 2-세포기배아를 3일 동안 배양하여 그 중 상태가 양호한 포배기 배아만을 선별하여 투명대를 제거한 후 사용하였다. 기본 배양액으로는 Ham's F-10을 사용하였으며, 배양 시 기본 배양액만을 사용한 경우를 group Ⅰ으로 하였고, 기본 배양액에 0.5% FBS를 첨가한 경우를 group Ⅱ, 0.5% FBS와 50% HSF를 첨가한 경우를 group Ⅲ , 100% HSF에 0.5% FBS를 첨가한 경우를 group Ⅳ,100% HSF만을 사용한 경우를 group Ⅴ로 하였다. 투명대를 제거한 포배기 배아를 각각의 HSF에 대한 5종류의 배양액에서 48시간 동안 배양하였다. 체외 착상 유무는 부착 부위에서 크기가 커진 영양세포들을 관찰하여 판정하였으며, 착상 부위의 표면적은 화상분석기를 이용하여 산출하였다. 결 과: 생쥐 배아의 체외 착상률은 group Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ에서 각각 0%, 98.9%, 77.5%, 40.4%, 10.0%로 나타났으며, 착상 부위의 평균 표면적은 group Ⅱ, Ⅲ, Ⅳ, Ⅴ에서 각각 $74,675{\pm}25,201{\mu}m^2$, $59,024{\pm}25,877{\mu}m^2$, $45,156{\pm}22,654{\mu}m^2$, $38,254{\pm}17,115{\mu}m^2$이었다. 체외 착상률과 부위의 표면적은 HSF의 농도가 증가함에 따라 통계적으로 유의하게 감소하였다(p<0.001). 결론:인간의 난관수종액(HSF)은 생쥐 배아의 체외 착상과 영양배엽세포의 증식을 억제하는 것으로 확인되었으며, 이러한 원인이 난관수종을 갖는 환자에서 임신율이 낮은 것과 밀접한 관련이 있을 것으로 생각된다.

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Frost Formation in a Straight Duct under Turbulent Flow (난류 유동 하에서 덕트 내의 착상)

  • Yang, Dong-Keun;Lee, Kwan-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.8
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    • pp.1114-1121
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    • 2003
  • A mathematical model considering the air side and the frost layer is presented to predict the frost layer growth. The standard k-$\varepsilon$ model for the air flow and the diffusion and energy equations for the frost layer are employed. The numerical results are compared with experimental data to validate the present model, and agree well with experimental data within a maximum error of 10%. The present model predicts well the frost properties and heat and mass transfer with respect to the frosting time. The variation of total heat transfer strongly depends on the operating condition, and has a similar trend to that of the sensible heat transfer. The frost properties along the flow direction are also investigated.

The theoretical Model for predicting the behaviors of the frost formation (착상 거동예측을 위한 이론적 모델)

  • Lee, Gwan-Su;Lee, Tae-Hui;Heo, Jeong-Hei
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.3
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    • pp.1096-1105
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    • 1996
  • A theoretical model of the frost formation has been presented to investigate the characteristics of the growth of frost layer by considering molecular diffusion of water vapor and heat generation caused by sublimation of water vapor in the frost layer. The present model was compared with existing experimental data as well as a previous model. The difference between the present model and existing experimental data was found to be about 6 percent. An analysis for the behavior of frost formation using present model shows a good agreement with the trend for a number of experimentally observed features. The present analysis can also provide the physical understanding on the phenomena of the frost formation.

The numerical model for predicting frost layer growth (서리층 성장 예측을 위한 수치적 모델)

  • Lee, K.S.;Jhee, S.;Lee, T.H.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.9 no.2
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    • pp.249-258
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    • 1997
  • In this study, a numerical model for analyzing frost formation phenomena on a cold flat plate has been developed. Both regions of air flow and frost layer have been coupled to calculate the amount of the heat and mass transfer between air flow and frost layer. Experiments have been also conducted to validate the numerical model. The present numerical results show a good agreement with the experimental data. The present numerical model also provides some useful data such as the temperature distribution inside the frost layer which could not be obtained through the experiments.

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In Vitro Regulation of DOC-1 Gene Expression in Uterine Endometrial Cells (체외 배양된 자궁내막세포에서의 DOC-1 유전자의 발현 조절)

  • Yang, Hye-Young;Cheon, Yong-Pil
    • Development and Reproduction
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    • v.13 no.4
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    • pp.297-303
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    • 2009
  • Implantation of blastocyst into the uterine endometrium is established by the existence of histologically and functionally prepared uterine endometrium. Doc-1, an oral cancer suppressor gene, is expressed under the control of steroid hormones and has been suggested as a proliferation regulator of endometrial cells. However, the role is not much clear and in this study we examined the expression modulation of Doc-1 in decidualizing cells in vitro. In vitro decidualization was performed in endometrial stroma cells using progesterone and estrogen. Until 24 hr after decidual induction the proliferation of stroma cell was significantly increased but decreased after then. On the other hand, most of the cells differentiated into decidual cell after 48 hr of induction. The Doc-1 protein was co-localized in a specific deciudal cells and colocalization rate was increased in a parallel manner with the induction time. Based on these results, it is suggested that Doc-1 expression is under the control of both steroid hormones and decidual signals, and Doc-1 protein is involved in suppression of the proliferation of decidualizing cells.

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A Decision-Theoretic Approach to Source Direction Finding Based on the Hopfield Neural Network (Hopfied 신경회로망에 바탕을 둔 음원 방향 탐지의 결정 이론적 접근)

  • Cheung, Wan-Sup;Jho, Moon-Je;Eun, Hui-Joon
    • The Journal of the Acoustical Society of Korea
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    • v.13 no.1E
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    • pp.55-63
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    • 1994
  • A decision-theretic concept is introduced to investigate whether targets of interest in array sensor systems are present at some steering direction or not. The solutions to this problem are described as a set of discrete numbers 0 or 1 corresponding to the direction under consideration. This coded number representation is transplanted in the optimisation technique based on the Hopfield neural network, which may provide an easy understanding of determining the direction of arrival (DOA) of sources. Difficulties encountered in using the conventional state schemes of Hopfield neural network models are addressed and their related issues are raised. To deal with them, an idea that a neuron that decreases more energy difference for its state change of 0 to 1can have higher priority in the order of state transition than others is introduced. This does not only lead to an new state update scheme but also opens a different story in comparison to previous work. To cast the perspectives of the proposed approach and illustrate its effectiveness in source direction finding in array sensor system. simulation results and related discussions are presented in this paper.

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3-Dimensional Culture System of Endometrial Cells for Studying the Human Implantation Mechanism (인간의 착상 기전을 연구하기 위한 3차원적 자궁내막 모델 확립)

  • Park, Dong-Wook;Yang, Hyun-Won;Kwon, Hyuck-Chan;Chang, Ki-Hong;Kim, Sei-Kwang;Cho, Dong-Jae;Oh, Kie-Suk
    • Clinical and Experimental Reproductive Medicine
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    • v.26 no.1
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    • pp.1-8
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    • 1999
  • In order to study the implantation mechanism various methods for culture of endometrial cells in vitro have been attempted. However, a disadvantage is that primary cultures of stromal and epithelial cells do not have the ability to differentiate, and therefore cannot be reproduced in the same manner as in vivo endometrium. The object of this study is to establish a three dimensional culture of endometrial cells which are both morphologically and functionally identical to in vivo endometrium. Endometrial tissues obtained after hysterectomies were cut into thin slices and treated with collagenase and trypsin-EDTA. The stromal cells and the epithelial cells were separated by centrifugation and cultured for 24 hours in DMEM media containing 10% FCS, 100 nM progesterone, and 1 nM estradiol. The cultured stromal cells were mixed with collagen gel and solidified, after which it was covered with matrigel. Epithelial cells were inoculated on the top and then cultured for 3 days. The three dimensionally cultured endometrial cells were stained for integrin ${\alpha}1,\;{\alpha}4,\;{\beta}3$, and cyclooxygenase-l, -2 by immunohistochemistry, which all showed strong expression. The cultured epithelial cells showed the formation of microvilli, tight junctions and pinopodes by electron microscopy. Studies are currently under way utilizing this three dimensional culture model to ascertain the interaction between the embryo and human endometrial cells at the time of implantation, and it is thought that further studies into a new culture environment which would allow longer periods of culture will be necessary.

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Establishment of Embryonic Stem Cell Line from Isolated Blastomeres from Mouse Preimplantation Embryos (생쥐 초기 배아에서 분리한 할구를 이용한 배아줄기세포주 확립)

  • Lim, Chun Kyu;Sung, Ji Hye;Choi, Hye Won;Cho, Jae Won;Shin, Mi Ra;Jun, Jin Hyun
    • Clinical and Experimental Reproductive Medicine
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    • v.33 no.1
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    • pp.25-33
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    • 2006
  • Objective: The aim of this study was to investigate whether embryonic stem (ES) cells can be established from isolated blastomeres of mouse embryos. Methods: Blastomeres were separated from mouse (C57Bl/6J) 2- or 4-cell embryos. Isolated blastomeres or whole 4-cell embryos were co-cultured with mitosis-arrested STO feeder cells in DMEM supplemented with recombinant murine leukemia inhibitory factor and ES-qualified fetal bovine serum. After the tentative ES cell lines were maintained from isolated blastomeres or whole embryos, some of them were frozen and the others were sub-cultured continually. Characteristics of tentative ES cell lines as were evaluated for specific genes expressions with immunocytochemistry and RT-PCR. Results: One ES cell line (3.0%) was established from isolated blastomere of 2-cell embryo and one cell line (4.0%) from isolated two blastomeres of 4-cell embryo. And five cell lines (16.7%) were established from whole 4-cell embryos. Both cell lines from isolated blastomere and whole embryo expressed mouse ES cell specific markers such as SSEA-1, Oct-4 and alkaline phosphatase. Marker genes of three germ layers were expressed from embryoid bodies of both cell lines. Conclusion: This study suggests that mouse ES cells could be established from isolated blastomeres, although the efficiency is lower than whole embryos. This animal model could be applied to establishment of autologous human ES cells from biopsied blastomeres of preimplantation embryos in human IVF-ET program.