• 한국식품저장유통학회지
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• 제23권7호
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• pp.931-938
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• 2016

본 연구는 건시의 냉동 온도를 달리하여, 저장기간 중 품질특성변화를 분석하고 비교하였다. 연구 결과, 유리당 함량은 $10^{\circ}C$, $-20^{\circ}C$에서는 저장기간 전체에서 SF가 더 많았다. 건시의 $L^*$값은 $10^{\circ}C$에서는 표면 갈변에 의해 감소하며, $0^{\circ}C$, $-10^{\circ}C$에서는 백분발생에 의해 그 값이 증가했다. QF, SF 모두 $0^{\circ}C$에서 백분이 가장 많이 발생하여 $L^*$값이 저장온도 중 가장 높았으며, QF에 백분이 더 많이 형성되어 그 값이 더 높았다. $a^*$값은 모든 저장온도에서 감소하는 경향을 보였으며, $10^{\circ}C$, $0^{\circ}C$에서 SF가 더 높았다. 조직감은 탄력성, 씹힘성, 경도를 조사하였으며, $0^{\circ}C$와 $-20^{\circ}C$를 비롯한 전반적인 건시의 경도는 전체 저장 기간 동안 SF에서 조직경화 현상이 더 심하다고 판단하였다. 가용성 탄닌 함량은 $-20^{\circ}C$를 제외하고 모든 저장온도에서 QF가 더 높은 경향이 나타났다. 본 연구의 결론으로 냉동조건에 따른 경향성 있는 결과가 도출된 것으로 미루어 보아, 건시의 저장 전 냉동온도는 저장 중 품질 변화에 영향을 줄 것으로 사료되며, 유리당, 색도, 가용성 탄닌 측면에서 SF, 즉 완만냉동 시료가 저장 중 품질특성이 더 좋을 것으로 보이지만 조직경화 면에서는 SF의 품질이 좋지 않다고 판단된다. 본 연구를 바탕으로 냉동 온도에 따른 관능적 평가와 미생물생육정도에 대한 추가적인 연구가 필요할 것으로 보인다.

• 대한생식의학회:학술대회논문집
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• 대한불임학회 2005년도 제49차 추계학술대회
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• pp.131.2-132
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• 2005

• 대한생식의학회:학술대회논문집
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• 대한생식의학회 2007년도 제53차 추계학술대회 초록집
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• pp.129.1-129.1
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• 2007

• 한국전산유체공학회지
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• 제7권4호
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• pp.19-27
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• 2002

An efficient implicit multigrid method is presented for the Navier-Stokes and k-ω turbulence equations. Freezing and limiting strategies are applied to improve the robustness and convergence of the multigrid method. The eddy viscosity and strongly nonlinear production terms of turbulence are frozen in the coarser grids by passing down the values without update of them. The turbulence equations together with the Navier-Stokes equations, however, are consecutively solved on the coarser grids in a loosely coupled fashion. A simple limit for k is also introduced to circumvent slow-down of convergence. Numerical results for the unseparated and separated transonic airfoil flows show that all computations converge well without any robustness problem and the computing time is reduced to a factor of about 3 by the present multigrid method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.31-34
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• 2002

An efficient implicit multigrid method is presented for the Navier-Stokes and $k-{\omega}$ turbulence equations. Freezing and limiting strategies are applied to improve the robustness and convergence of the multigrid method. The eddy viscosity and strongly nonlinear production terms of turbulence are frozen in the coarser grids by passing down the values without update of them. The turbulence equations together with the Navier-Stokes equations, however, are consecutively solved on the coarser grids in a loosely coupled fashion. A simple limit for k is also introduced to circumvent slow-down of convergence. Numerical results for the unseparated and separated transonic airfoil flows show that all computations converge well without any robustness problem and the computing time is reduced to a factor of about 3 by the present multigrid method.

• International Journal of Internet, Broadcasting and Communication
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• 제6권2호
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• pp.20-24
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• 2014

These days the large-scale car accidents have often been occurred by overspeeding in disregard of sharp curve, foggy and freezing regions. This paper has proposed the algorithm to calculate the safety speed in real time that can protect the car accidents under these weather and road conditions using Fuzzy reasoning theory. Under raining and snowing, drivers have to slow down the traffic safety speed by 1/3 of the traffic safety speed indicated on the existing speed sign plate based on their decision. So it is difficult to calculate and then observe the safety speed. This paper has performed the simulation that provides the deivers with the optimal safety speed considering the road and weather conditions in real time to improve these problems. We have proved this method can improve more 25% than the existing one.

• 대한생식의학회:학술대회논문집
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• 대한불임학회 2002년도 제43차 추계학술대회
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• pp.97-97
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• 2002

• Geomechanics and Engineering
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• 제36권4호
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• pp.391-406
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• 2024

In order to study the soil seasonal dynamic characteristics in the regions with four distinct seasons, the soil dynamic triaxial experiments were conducted by considering the environmental temperature range from -30℃ to 30℃. The results demonstrate that the dynamic soil properties in four seasons can change greatly. Firstly, the dynamic triaxial experiments were performed to obtain the dynamic stress-strain curve, elastic modulus, and damping ratio of soil, under different confining pressures and temperatures. Then, the experiments also obtain the dynamic cohesion and internal friction angle of the clay under the initial strain, and the changing rule was summarized. Finally, the results show that the dynamic elastic modulus and dynamic cohesion will increase significantly when the clay is frozen; as the temperature continues to decrease, this increasing trend will gradually slow down, and the dynamic damping ratio will go down when the freezing temperature decreases. In this paper, the change mechanism is objectively analyzed, which verifies the reliability of the conclusions obtained from the experiment.

• 한국수정란이식학회지
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• 제23권3호
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• pp.223-227
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• 2008

The cryopreservation of Hanwoo embryos has become an integral part of assisted reproduction in animal. The objective of this study was to assess the effect of The objectives of this study were: (1) to evaluate the influence of bovine embryo developmental stage on in vitro embryo development after freezing, (2) to study the efficiency compared with conventional freezed embryos at different embryo source. For conventional slow-freezing, day 7 or 8 expanded blastocysts were collected. The standard freezing medium was 1.8 M ethylene glycol (EG). Embryos were equilibrated in 1.8 Methylene glycol(EG) with 0.1 M sucrose in Dulbecco's phosphate-buffered saline (D-PBS) supplemented with 0.5% bovine serum albumin. Embryos were then loaded individually into 0.25 ml-straw and placed directly into cooling chamber of programmable freezer precooled to $-7^{\circ}C$, after 2 min, the straw was seeded, maintained at $-7^{\circ}C$ for 8 min, and then cooled to $-35^{\circ}C$ at $0.3^{\circ}C$/min, plunged and stored in liquid nitrogen for at least 3 days. For thawing, the straw containing embryos were warmed in air for 10 see and exposed to $37^{\circ}C$ water for 20 sec. Straws were then removed from $37^{\circ}C$ water. Rates of blastocyst survive and hatched were evaluated at 12 to 48h post-warming. The re-expansion and hatched rates of morula embryos were significantly lower than those obtained for blastocysts and expansion blastocysts (31.6%, 10.5% vs, 68.9%, 22.2% vs, 73.7%, 53.6%, respectively). No differences in re-expansion rates were found between in vivo and in vitro blastocysts. whereas hatched rates was significantly higher (51.2%) in vivo compared with in vitro embryos (18.6%). in conclusion, demonstrate that conventional freezing can be used successfully in cryopreservation of in vitro and in vivo bovine embryos, and that it might be considered for use in commercial programs and embryo preservation.

• Clinical and Experimental Reproductive Medicine
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• 제27권1호
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• pp.59-65
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• 2000

Objective: The purpose of this study was to determine the important factors affecting survival and pregnancy rate in frozen-thawed embryo transfer cycles. Methods: we performed retrospective analysis in 738 cycles of frozen-thawed embryo transfers, in relation to the insemination methods, the freezing stage of embryo, patient's age, infertility factors and the origin of injected sperm in ICSI cycles. After conventional IVF or ICSI, the supernumerary PN stage zygotes or multicellular embryos were cryopreserved by slow freezing protocol with 1,2-propanediol (PROH) as a cryoprotectant. Results: The survival rates of thawed embryos were 69.3% (1585/2287) in conventional IVF group and 71.7% (1645/2295) in ICSI group. After frozen-thawed embryo transfers, 27.0% (92/341) and 32.0% (109/341) of pregnancy rates were achieved in conventional IVF and ICSI group, respectively. There were no significant difference in the survival and pregnancy rates according to the insemination methods, the freezing stage and patient's age. However, the pregnancy rate (36.2%) of male factor infertility was significantly higher than the tubal (27.2%) and other female factor infertility (22.9%). In ICSI group, the origin of injected sperm did not affect the outcome of frozen-thawed embryo transfer cycles. Conclusion: The present study demonstrates that acceptable clinical outcomes can be achieved after the transfer of frozen-thawed embryos regardless of the stage of embryos for freezing, the patient's age and the origin of injected sperm.