• 한국작물학회지
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• 제23권1호
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• pp.26-31
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• 1978

맥류의 생육시기에 따라 토양분을 과습상태로 침수하였을 때 생육과 수양에 미치는 피해양상과 정도의차이를 조사하였는 바 그 결과를 요약하면 다음과 같다. 1. 침수기간중 토양온도는 표준구보다 침수구가 고온으로 경과하였는데 오후 3시가 오전 10시보다 더욱 높았으며 토양산화환원전위는 표준구에 비하여 침수구가 현저히 저하하였다. 2. 침수로 인한 초장생육에 피해가 심한 시기는 전맥종이 신장기였으며 다음은 분얼기였고 경수증가피해가 심한 시기는 반대로 분얼기이고 다음이 신장기였으며 수잉기와 등숙기에는 그 차가 경징하였는데 맥종별로 초장과 경수피해가 큰것은 대맥이었고 적은것은 소맥이었다. 3. 침수로 인하여 수획시 간장감소가 심하였던 시기는 이조맥과 대맥은 신장기였으나 소맥은 수잉기였으며 수장은 이조맥과 소맥이 분얼기에 가장 저하하였다. 주당수수와 수당립수의 감소피해가 큰 시기는 전맥종의 유방분얼이 결정되고 소수분화가 이루어지는 분얼기와 신장기였다. 5. 천립중의 피해가 큰 시기는 입의 대소가 결정되는 수잉기로서 특히 소맥과 이조맥의 피해가 심하였는데 이때는 상위절간신장이 조해되어 출수는 지연되고 등숙이 불량하였다. 6. 침수구의 수양감수는 이조맥과 대맥은 수수와 입수감소 피해가 심하였던 신장기였고 다음은 분얼기였으며 소맥은 천립중의 피해가 큰 수잉기였고 다음이 신장기였는데 맥종별로는 소맥의 피해가 적고 다음이 대맥이었으며, 이조맥의 감수가 가장 심한 경향이었다.

• Clinical and Experimental Reproductive Medicine
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• 제20권1호
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• pp.31-36
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• 1993

The effects of freezing and 1,2-propanediol on early and late pronucleate stage mouse ova were investigated in terms of survival after thawing and development in vitro. The samples were divided into two groups according to different age in pronucleate ova: ova in(1) early pronuclear stage with two distant pronuclei at 18h after hCG injection, and (2) late pronuclear stage with adjacent pronuclei at 30h. Zygotes in the late pronuclear stage have been proven to be more resistant to 1,2-propanediol, showing a significantly higher developmental rate than zygotes in early stage (80.3 versus 66.3%, <0.05), but survival rate was similar in the two groups (91.0 versus 93.5%). After freezing and thawing, survival and developmental rates were decreased in both groups when compared to the control group (54.3 versus 92.3%, 47.7 versus 73.3%. respectively). And developmental rate in the late pronuclear stage zygotes showed significantly higher than in early (55.4 versus 40.0%) after thawing. In conclusion, early pronucleate mouse ova have a lower developmental capacity in vitro and a lower survival rate after freezing and thawing than late ova. These findings suggest that the timing of freezing could be important for survival and further development in vitro in cryopreservation of human pronucleate ova.

• 한국환경생태학회지
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• 제19권1호
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• pp.1-8
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• 2005

창포를 이용하여 질소와 인의 농도별, 식물의 생장단계별, 오염수의 체류시간별로 질소와 인의 제거효과를 분석하였던 바, 그 결과를 요약하면 다음과 같다. 체류 1시간 후에 수중의 질소와 인의 함량을 현저히 감소시켰으나, $2\~4$시간 후에는 감소율이 극히 낮았다. 이러한 현상은 식물의 생장초기, 생장기, 생장최성기에서 동일하였다. 수중에 질소와 인의 함량이 많을수록 제거율이 높았고, 인보다는 질소의 제거효과가 크게 나타났다. 생장최성기에 가장 많은 질소와 인을 제거하였고 다음으로 생장기, 생장초기의 순이었으나, 생장단계간의 차이는 극히 작았다. 동일 포트에 4일 동안 체류시킨 것보다 2일 체류 후에 다른 포트로 시험수를 옮긴 것이 질소와 인의 제거율이 약간 높았다.

• 설비공학논문집
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• 제19권1호
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• pp.19-27
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• 2007

Analytical investigation on the performance of a two stage twin rotary compressor for $CO_2$ heat pump water heater system has been carried out. A computer simulation program was made based on analytical models for gas compression in control volumes, leakages among neighboring volumes, and dynamics of moving elements of the compressor. Calculated cooling capacity, compressor input, and COP were well compared to those of experiments over the compressor speeds tested. For the operating condition of suction pressure of 3 MPa, and discharge pressure of 9 MPa, and compressor inlet temperature of $35^{\circ}C$, the compressor efficiency was calculated to be 80.2%: volumetric, adiabatic, and mechanical efficiencies were 88.3%, 93.2%, and 92.7%, respectively. For the present compressor model, volumetric and adiabatic efficiencies of the second stage cylinder were lower by about $6{\sim}7%$ than those of the first stage mainly due to the smaller discharge port at the second stage. Parametric study on the discharge port size showed that the compressor performance could be improved by 3.5% just by increasing the discharge port diameter by 20%.

• Smart Structures and Systems
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• 제26권6호
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• pp.693-701
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• 2020

The conventional Kalman Filter (KF) provides a promising way for structural state estimation. However, the physical parameters of structural systems or models should be available for the estimation. Moreover, it is not applicable when the loadings applied to the structures are unknown. To circumvent the aforementioned limitations, a two-stage KF with unknown input approach is proposed for the simultaneous identification of structural parameters and unknown loadings. In stage 1, a modified observation equation is employed. The structural state vector is estimated by KF on the basis of structural parameters identified at the previous time-step. Then, the unknown input is identified by Least Squares Estimation (LSE). In stage 2, based on the concept of sensitivity matrix, the structural parameters are updated at the current time-step by using the estimated structural states obtained from stage 1. The effectiveness of the proposed approach is numerically validated via a five-story shearing model under random and earthquake excitations. Shaking table tests on a five-story structure are also employed to demonstrate the performance of the proposed approach. It is demonstrated from numerical and experimental results that the proposed approach can be used for the identification of parameters of structure and the external force applied to it with acceptable accuracy.

• 한국항공우주학회지
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• 제42권4호
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• pp.326-335
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• 2014

터보블로워는 상대적으로 적은 체적유량에서 높은 압력이 요구되는 곳에 사용되는 대표적인 유체기계로서 다양한 산업에 응용되어 사용된다. 본 연구에서는 고속으로 회전하는 소형 2단 터보블로워의 정압상승 메커니즘을 이해하기위해, 1단 임펠러 영역과 터보블로워 전체 영역에 대해서 상용툴인 ANSYS 14.5를 이용하여 CFD해석을 수행하였다. CFD 해석과정에는 역압력 구배에 의한 유동박리 예측에 적합한 k-${\omega}$ SST 난류 모델을 적용하였다. 터보블로워의 전산해석 결과는 KS B 6311 및 KS A 0612에 따른 성능시험방법을 통하여 해석기법이 타당함을 검증하였다. CFD 해석결과 터보블로워의 압력상승은 선형적으로 나타나지 않으며, 안내깃에서의 손실과 케이싱과 임펠러 간극에서 손실이 발생하는 것으로 분석되었다. 소형 2단 터보블로워를 공력성능을 예측하기 위해서는 전체 유동영역에 대한 전산 해석이 필요하며, 실험과 전산해석의 오차에 대해 고려된 전산해석 결과가 선정되어야 한다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권9호
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• pp.3891-3893
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• 2014

Background: Most patients with endometrial cancer have stage I disease. Adjuvant therapy in stage IB (formerly IC) endometrial cancer is controversial, treatment options including observation or brachytherapy/radiotherapy in grade 1-3 patients with or without chemotherapy. The purpose of this study was to assess the outcomes of our patients with stage IB endometrioid endometrial cancer. Materials and Methods: Sixty two patients with stage IB endometrial cancer and endometrioid histology were retrospectively evaluated. All patients were initially treated surgically by the same surgeon with comprehensive staging, i.e. total abdominal hysterectomy, bilateral salphingooopherectomy, bilateral pelvic and paraaortic lymph node dissection and omentectomy. Adjuvant radiotherapy was discussed with patients and utilized by those who accepted. Adjuvant chemotherapy was not given to any of the patients. Results: Median age was 62 (range, 42-95). Ninety percent of the patients had grade 1-2 disease. Thirteen patients (21%) received intra vaginal brachytherapy (IVBT) and one received whole pelvic radiotherapy (WPRT). Median follow-up time was 46 months (range, 9-77 months). Three patients experienced recurrence (4.8%), two of them died on follow-up and one was still alive at last visit. Two patients with recurrence had FIGO grade 2 tumors and one had a grade 3 tumor. Two patients (3.2%) died without evidence of recurrent disease. Relapse free survival at 5 years was 94.4% and overall survival was 93.1%. Conclusions: Patients with stage IB disease in our study demonstrated relatively low recurrence rates although the majority of them received no adjuvant treatment. Surgery alone may be sufficient for most patients with this stage of endometrial cancer.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.359-362
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• 2003

The aerostatic stage. which is used in semiconductor process, is demanded higher velocity and more precise accuracy for higher productivity and integrated performance. So, in the case of XY stage, H type structure, which is designed two co-linear axis of guide-way, driving force in one surface, has advantage of velocity and accuracy compared to conventional tacked type XY stage. To analyze characteristics of H type aerostatic stage, H type aerostatic surface XY stage is made, which is driven by linear motor and detected position with precise optical linear scale. And, analyze characteristics of motion error, effect of angular motion on positioning accuracy error and effect of simultaneous control on variation of velocity.

• 한국기계가공학회지
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• 제11권2호
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• pp.112-117
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• 2012

This paper presents a new stopper mechanism for precision stage by using the Piezoelectric element actuator. The new stage including a new stopper mechanism has the precision positioning mechanism that was been developed for generation displacements with nanometer accuracy and a millimeter dynamic range simulataneouly. The stage is composed not of the mechanical two stopper but of only one Piezoelectric element actuator. The characteristics for the new stage and the stopper have been evaluated experimentally. As the results, we can know that the linearity error characteristics of stage is 30nm in the $20{\mu}m$ measurement range. In addition, the experimental results are confirmed the possibility of the movement in millimeter range.

• 한국기계가공학회지
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• 제7권1호
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• pp.32-37
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• 2008

This paper presents a new precision stage by using the PZT actuator and stepping motor. The stage have the precision positioning mechanism that has been developed for generation displacements with nanometer accuracy and a millimeter dynamic range simulatneously. The stage is composed not of the mechanical elastic hinge but of the clamp, and only one PZT actuator. The displacement of stage is acquired by the control of the two clamp between the PZT actuator. The results of the FEM analysis in the contact part of the clamp and basic properties of the positioning system are also presented. Using the new stage proposed in this paper.