• Proceedings of the KIPE Conference
• /
• 2014.07a
• /
• pp.363-364
• /
• 2014

본 논문에서 제안한 단독운전 알고리즘은 무효전력 주입을 기반으로 설계하였다. 정상상태에서는 무효전력을 주입하지 않고 계통전압, 고조파, 주파수의 변동을 확인하여 제 1차와 2차 단계를 통해 무효전력의 주입량과 주입 방향을 결정하여 주입한다. 제안한 방법을 통하여 단독으로 운전될 때 뿐만 아니라 다수대 병렬운전할때도 단독운전을 200ms 이내에 검출됨을 확인하였다.

• Korean Journal of Poultry Science
• /
• v.32 no.4
• /
• pp.225-229
• /
• 2005

Microinjection of recombinant retrovirus beneath the blastoderm of non-incubated chicken embryo is now the most widespread method for generating transgenic chickens, but transgenesis rates are very low. So to improve this problem, we first introduced retrovirus vector carrying RSV-GFP gene to an one-cell embryo culture system. To investigate whether retrovirus could work on an one-cell chicken embryo, we microinjected the concentrated retrovirus stocks into the germinal disc of one cell or stage-X chicken embryos. Analysis of reporter gene expression on day 4 embryos showed that GFP expression was observed in the only stage-X chicken embryo but was not in the one-cell embryo group. These results suggest that retrovirus system is the most efficient method to generate transgenic chickens in the stage-X embryo.

• Tunnel and Underground Space
• /
• v.26 no.1
• /
• pp.12-23
• /
• 2016

For a successful accomplishment of Carbon Capture Sequestration (CCS) projects, appropriate injection conditions should be designed and optimized for site specific geological conditions. In this study, we evaluated the effect of injection conditions such as injection temperature and injection rate on the geomechanical stability of CCS system in terms of TOUGH-FLAC simulator, which is one of the well-known T-H-M coupled analysis methods. The stability of the storage system was assessed by a shear slip potential of the pre-existing fractures both in a reservoir and caprock, expressed by mobilized friction angle and Mohr stress circle. We demonstrated that no tensile fracturing was induced even in the cold CO2 injection, where the injected CO2 temperature is much lower than that of the reservoir and tensile thermal stress is generated, but shear slip of the fractures in the reservoir may occur. We also conducted a scenario analysis by varying injected CO2 volume per unit time, and found out that it was when the injection rate was decreasing in a step-wise that showed the least potential of a shear slip.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.7
• /
• pp.50-57
• /
• 1989

Tapered etching of polysilicon films has been achieved by implanting phosphorus ions into the polysilicon film and using plasma etch in either $CF_4-O_2\;or\;SF_6$. A two-step plasma etching method is also proposed to control the taper angle of the etched edge without changing the implantion conditions. The taper angle is determined by the ratio of the etch rate of the undamaged region to that of the damaged top region of the polysilicon layer. The ratio is found to be dependent on the implantion dose, the implantion energy and the anisotropy of etching. The minimum angle in our experiments is about $10^{\circ}$. When the two-step etching method is employed, the taper angles can be controlled from the minimum angle up to about $55^{\circ}$.

• Journal of the Korean GEO-environmental Society
• /
• v.13 no.10
• /
• pp.77-83
• /
• 2012

Recently, excavations using propped walls were popularized in downtown due to reduced settlement of nearby structures. These excavations is induced strain to propped walls or settlement in near ground. In this study, the ground reinforcing effect was proven using NDS, which is an inorganic injection material. Injection tests were performed to compute optimum injection pressure and volume. Next, calibration chamber tests were performed by using computed injection pressure and volume, and wall behaviour was examined for overburden pressures of 50kPa and 150kPa. Ground reinforcing effect was shown when the material behind the propped wall was grouted. From test results, optimum injection pressure was 350kPa and the optimum volume was 10L considering economics. Calibration chamber test results show that after the material was grouted, the maximum settlement was reduced to 19% of the non-grouted condition. For overburden pressures of 50kPa and 150kPa behind the wall, the settlement of the wall increased by 58% and 57% when compared to the case of no overburden pressure.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2017.05a
• /
• pp.387-387
• /
• 2017

인공함양 시설을 설계 및 운영하는 단계에서 설치 예정부지의 자연적 특성(지형, 지질, 기후 등)과 인공적 특성(주입정과 양수정의 거리, 주입량, 양수량 등)은 중요한 인자라고 볼 수 있다. 인공함양 예정 부지의 개념모델을 설정하고 수리전도도와 이격거리(주입정과 양수정의 직선거리)에 대한 민감도 분석을 수행하였다. 인공함양 예정 부지는 충적대수층이며, 인공함양 주입량과 양수량은 $150m^3/day$로 동일하게 설정하였다. HydroGeoSphere 모델링을 통한 민감도 분석은 수리전도도($10^{-1}cm/sec$, $10^{-2}cm/sec$, $10^{-3}cm/sec$, $10^{-4}cm/sec$)와 이격거리(10 m, 50 m, 100 m) 조건에 대해 총 12회 수행하였다. 수리전도도가 $10^{-1}cm/sec$ 및 $10^{-2}cm/sec$인 경우의 모델링 결과, 이격거리가 100 m 범위 이내에서는 지하수위 변동이 발생하지 않았다. 수리전도도가 $10^{-3}cm/sec$인 경우의 모델링 결과, 이격거리가 10 m일 때 5 m 이내의 수위하강이 발생하고 영향반경은 약 14 m 정도로 나타났고, 이격거리가 50 m일 때 5 m 이내의 수위하강이 발생하고 영향반경은 약 31 m 정도로 나타났고, 이격거리가 100 m일 때 5 m 이내의 수위하강이 발생하고 영향반경은 약 34 m 정도로 나타났다. 수리전도도가 $10^{-4}cm/sec$인 경우의 모델링 결과, 이격거리가 증가할수록 양수에 의한 수위하강과 영향반경이 증가하였으며, 낮은 수리전도도로 인해 양수로 인한 수두손실을 회복할 수 없었기에 양수정 주변에서 반경 수십 m 이상의 수두하강 영역을 형성하고 주입정 근처에서는 주입속도가 대수층의 투수능력에 비해 상당히 높기 때문에 5 m 정도의 수위상승이 나타났다. 모델링 결과를 분석하여, 수리전도도가 $10^{-3}cm/sec$ 이하이고 이격거리가 10 m 범위 이상인 충적대수층에 $150m^3/day$를 주입하면서 동시에 $150m^3/day$를 양수하는 시스템에서는 지하수위변동이 발생하므로 주입량과 양수량의 조절이 필요하다는 것을 확인하였다.

• The Journal of Engineering Geology
• /
• v.28 no.2
• /
• pp.193-206
• /
• 2018

In this study, as part of the "Small-scale $CO_2$ Injection-Demonstration Project in Offshore Pohang Basin", we performed drilling and completion of a $CO_2$ injection well from the offshore platform installed in the Yeongil Bay, Pohang city, Gyeongsang buk-do. The drilling of injection well was carried out from an offshore platform installing on the sediment formations of the Pohang Basin. Drilling diameters were reduced by stages, depending on the formation pressure and groundwater pressure along a depth and the casing installation and cement grouting in drilled hole were performed at each stage. The injection well was drilled to a final depth of 816.5 m with a hole diameter of 4 7/8 inches (${\Phi}124mm$) and the perforated casing for an injection section was installed in a depth of 746.5~816.5 m. Injection tubing, packer, and christmas tree were installed for the completion of an injection well for $CO_2$. The validation project of the $CO_2$ injection was accomplished successfully by drilling the injection well and installing the injection facilities, and through the suitable $CO_2$ injection process. The current injection facility is a facility for small-scale injection demonstration of 100 tons. In the case of large-scale demonstration facility test of a capacity of 10,000 tons, research is underway through the upgrading of the injection facilities.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2005.11a
• /
• pp.70-71
• /
• 2005

본 연구는 1세포기 닭 수정란에 retrovirus vector (RSV-GFP)를 도입하여 외래유전자의 핵 전이 효율을 높이고자 하였다. 실험은 polybrene과 retrovirus 혼합물을 1세포기 또는 배반엽 단계의 수정란 세포질에 미세주입하고 배양 3 또는 4일차에 GFP의 발현 양상들을관찰하였다. 실험의 결과는 배반엽 수정란에서 GFP발현을 관찰할 수 있었으나, 1세포기 수정란에서는 GFP의 발현을 관찰할 수 없었다. 연구결과는 형질전환닭 생산에 있어서 가장 효율적인 방법은 배반엽 단계에 retrovirus를 미세주입하는 방법임을 보여주고 있다.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.11b
• /
• pp.697-702
• /
• 1996

원전 배관계통에 LBB를 적용하면 배관파단으로 인한 동적영향(dynamic effect)을 고려하지 않아도 되므로 각종 구조물의 설계가 단순해지고, 배관파단에 대비해 설치하였던 각종 지지구조물들을 제거할 수 있으므로 설계비용 절감 등 경제적 이점을 얻을 수 있다. 본 논문의 목적은 차세대원전 안전주입 및 정지냉각계통 배관에 대해 설계초기단계에서 LBB적용 여부를 판단할 수 있는 배관평가선도를 개발하는 것이다. 이를 위해 먼저 배관재료의 응력-변형률곡선을 사용하여 감지가능한 균열길이를 산출하였으며, 3차원 유한요소해석과 배관재료의 파괴저항곡선을 이용한 균열안정성평가를 수행하여 배관평가선도를 개발하였다. 본 연구에서 개발한 배관평가선도를 배관설계초기단계에 사용하면 LBB적용여부로 인한 설계변경과정이 불필요하므로 전체공기를 단축할 수 있으며, 특정한 배관계통이 아닌 일반 배관계통에 적용할 수 있으므로 LBB해석회수를 상당히 줄일 수 있다.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.11
• /
• pp.1595-1602
• /
• 2010

A disposable drug infuser is used to provide drugs to patients who are not hospitalized; in this infuser, an elastic recovery force is exerted by a diaphragm made of a rubber-like materialsuch that a constant amount of drugs is provided to a patient. The drug infuser has to control the speed and amount of drugs to be released, as well as the overall duration for which they are to be administered. However, in a drug infuser with an elastic diaphragm, the infusion pressure depends on the amount of drug remaining within the infuser, and the amount of drug infused gradually decreases as the amount remaining in the infuser decreases. In this study, a finite element procedure involving the application of the fluid-structure interaction technique was developed and the performance of the elastic type disposable drug infuser was analyzed. The optimum design for ensuring that the infusion pressure remains constant throughout the duration of usage, including during infusion and discharge, was determined by this procedure.