• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.245-248
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• 2011

다중펄스 로켓모타 기술은 일회성 추력발생 방식에 비하여 여러 가지 장점이 있다. 추진기관에 펄스분리장치를 적용하면 적절한 추력배분을 통하여 유도탄의 사거리 연장 및 종말속도를 향상시킨다. 본 연구에서는 격벽형 펄스분리장치의 성능을 검증하기 위하여 실물형 Heavy-type 추진기관을 설계, 제작하여 지상연소시험을 수행하였다. 지상연소시험 시 계측한 추진기관의 압력, 추력, 진동 결과를 바탕으로 펄스분리장치의 파열특성인 파열시간과 파열압력 분석을 실시하였다. 그 결과, 2단 연소압력의 30% 이하에서 파열되어야 한다는 요구조건을 만족함을 확인할 수 있었다.

• 한국초전도ㆍ저온공학회논문지
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• 제11권4호
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• pp.8-11
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• 2009

This study introduced wastewater treatment method by High Gradient Magnetic Separation (HGMS). HGMS treatment was high efficient method for various industrial wastewaters. The system is currently research state, but we have surveyed commercialize the technology for industry. In rolling plate process, coolant wastewater was recycled by sedimentation and sand filter system. It needs several large reservoirs and long time to remove suspended solid (SS) like metal fines and iron oxide in hot rolling plate making process. If removing rate of suspended solid in rolling coolant wastewater is improved by using HGMS system, the productivity of working process can be increased and the area of reservoir can be reduced. We manufactured high temperature superconducting HGMS system that had a purpose to treatment of coolant wastewater in rolling plate process. We fabricated the prototypes of magnetic matrix filter consisting of stainless steel 430 mesh, which is a core component in the magnetic separation system, In our basic preliminary experiment using HGMS system, it has been clear that the fine paramagnetic particles in the coolant wastewater obtained from rolling plate process of POSCO can be separated with high efficiency.

• Advances in concrete construction
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• 제9권1호
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• pp.71-82
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• 2020

One of the most suitable methods in structural design is seismic separator. Lead-Rubber Bearing (LRB) is one of the most well-known separation systems which can be used in different types of structures. This system mitigates the earthquake acceleration prior to transferring to the structure efficiently. However, the performance of this system in concrete structures with different heights have not been evaluated thoroughly yet. This paper aims to evaluate the performance of LRB separation system in concrete structures with different heights. For this purpose, three, 16, and 23 story concrete structures are equipped by LRB and exposed to a far-field earthquake. Next, a time history analysis is conducted on each of the structures. Finally, the performance of the concrete structures is compared with each other in the term of their response to the earthquakes and the formation of plastic hinges. The results of the paper show that the rate of change in acceleration response and the ratio of drift along the height of 8 and 23 stories concrete structures are more than those of the 16-stories, and the use of LRB reduces the formation of plastic joints.

• 한국수산과학회지
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• 제30권2호
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• pp.239-243
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• 1997

포말분리관에서 양어장 순환수를 일정하게 공급하여 분리 실험을 수행하며 체류 시간, 공탑 공기 유속, 포말층 높이 등의 영향에 따른 포말 분리관의 각 성분의 분리 특성을 연구한 결과 체류 시간 및 공탑 공기 유속이 증가할수록 TSS, TA및 $NO_2^-$ 성분의 제거율도 비례적으로 증가하였다. 그리고 포말층의 높이가 증가할수록 TA의 제거율은 월등히 증가한 반면에 $NO_2^-$, TSS의 제거율은 일정하게 유지되었다. 포말분리기의 공탑 공기 유속 및 포말층 높이가 증가할수록 순환수내의 용존산소도 증가하여 포말분리기는 양어장 순환수의 산소 공급 장치로도 활용되었다. 포말분리법은 어류 성장에 유해한 TSS, TA, $NO_2^-$를 단기간에 제거할 수 있고 어류 성장에 필요한 산소를 공급할 수 있는 매우 효과적인 방법으로 판단되었다.

• Restorative Dentistry and Endodontics
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• 제37권2호
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• pp.74-78
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• 2012

Objectives: This study aimed to evaluate the relationship between the cyclic fatigue of a K3 file and internal stress intentionally induced until the activation of the autostop function of the torque-controlled motor. Materials and Methods: K3 (Sybron Endo) .04 and .06 taper, size 25, 30, 35, 40 and 45 were used in this study. To give the internal stress, the K3 files were put into the .02 taper Endo-Training-Bloc (Dentsply Maillefer) until the activation of the auto-stop function of the torque-controlled motor. The rotation speed was 300 rpm and torque value was 1.0 $N{\cdot}cm$. K3 were grouped by the number of induced internal stress and randomly distributed to 4 experimental groups (n = 10, Stress 0 [control], Stress 1, Stress 2 and Stress 3). For measuring the cyclic fatigue failure, the K3 files were worked against a sloped glass block and time for file separation was recorded. Data was statistically analyzed Statistical analyses were performed using two-way ANOVA and Duncan post-hoc test at p < 0.05 level. Results: Except .04 taper size 30 in Stress 1 group, there were statistically significant differences in time for file separation between control and all experimental groups. K3 with .04 taper showed higher cyclic fatigue resistance than those of .06 taper. Conclusion: In the limitation of this study, the cyclic fatigue of the K3 file was influenced by the accumulated internal stress from use until the auto-stop function was activated by the torque-controlled motor. Therefore, clinicians should avoid the reuse of the K3 file that has undergone auto-stops.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
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• pp.295-297
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• 1986

In this study, the strap down INS on an earth satellite launch vehicle is simulated with different computing cycles between processing the IMU signals and the navigation computation. At the time of separation of booster, error are discussed. The acceptable computing cycles can be determined by simulation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.42-47
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• 1993

Importance of separation of a nonlinear dynamical system into nonlinear static part and linear dynamical part was insisted in designing a controller for the nonlinear system. We further proposed compensation techniques for oscillation of controlled variables caused by system time delay and compensation of steady state errors caused by modelling errors of the systems. The proposed principle of designing procedure and the compensation methods were discussed by applying them for temperature and level control of an actual tanked water system.

• 한국식품영양학회지
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• 제1권2호
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• pp.9-17
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• 1988

The morphological changes of fresh beef treated with ficin(0.1% : 2hrs, 6hrs) were examined with optical microscope (OM, LM), the results obtained were as follows : Connective tissue protein in fresh beef treated with ficin was occurred swelling and separation of endomysial reticulum with time, followed showing granulation and solubilization slightly. Myofibrillar protein was loosed wavy contractile muscle fiber, and showed erosin, cracks and breaks in fibers with time.

• 방사선산업학회지
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• 제7권1호
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• pp.1-5
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• 2013

Photostimulated luminescence (PSL) and thermoluminescence (TL) analyses were applied to identify the cookie molds mixed with 2 mg of 10 kGy-irradiated minerals according to cookie processing methods and sonication time (0~60 min) for mineral separation. PSL analysis showed that photon counts of cookies, dried or baked, ranged intermediate levels between the lower and upper threshold (700~5,000 counts/60 s), thereby showing its unsuitablility for screening of irradiated cookie. The TL glow curve intensities, measured according to mineral separation time (5, 10, 20, 40 and 60 mins) from the cookies using a sonicator, were high enough to identify irradiation status and significantly increased with the time in dried cookies. Those of baked cookies, however, were relatively low and not linearly increased with the time, but still possible to identify them (p<0.05).

• 대한전자공학회논문지
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• 제24권1호
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• pp.20-27
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• 1987

The hierarchical approach method is proposed to sperate each different time scale sub-systems from linear time invariant multi-parameter singular perturbation systems. By means of this proposal, the original multi-parameter singular perturbation systems is completely separated into independent subsystems with each different time scale. It is also investigated that the controllability of the system is invariant. And this paper applies singular perturbation methods to the minimum control effort problem for linear time invariant systems with constrained controls. Also near-optimum control theory, which is based on dividing the total time interval with the time scales respectively, is proposed. As a result, the time scale separation method is show to be particularly useful in a near optimum design which can be otained through a decentralized control structure.