• 전력전자학회논문지
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• 제5권4호
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• pp.394-402
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• 2000

본 논문온 전압안정도에 Brfurcation 이론을 적용하여 해석하고, FACTS기가인 SVC와 UPFC를 전력계통에 연계하였을 때 전압안정도가 향상되는 효과를 보여주고 있다. 전압안정도는 일반적으로 시스템 파라미터(유효전력 또는 무효전력}를 포행하는 고도의 비선형 동적시스템의 식들에 의해 표현된다. 때때로 전력계통에서의 파라미터 변이는 시스템 불안정을 일으키는 복잡한 동작을 일으킬 수도 있다. 전력계통에서의 FACTS의 연계는 이러한 전압안정도의 범위를 증가시킨다. FACTS를 이용하여 불안정한 HopF Bifurcation과 Saddle Node Bihlfcation을 지연시킴에 의해서 전압안정도기 향상됨을 사례연구를 통하여 입증하였다.

• 항공우주시스템공학회지
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• 제7권2호
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• pp.23-28
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• 2013

This is a research on the method of how to improve lateral stability for the small general aviation airplane to meet the FAR part 23 requirements. This research is based on the experience of certification flight tests of KC-100 airplane for Korea first type certification. KAS/FAR Part 23.177 is the static lateral and directional stability requirement. And, 23.177(b) requires to show the tendency to raise the low wing in steady heading side slip maneuver. However, it is very difficult for the low wing to be raised at the low speed during the steady heading side slip maneuver. So, the requirement allows not be negative at the $1.2V_{S1}$ speed and takeoff configuration. (static stability requirement requires low wing picked up at any speed except $1.2V_{S1}$ speed and takeoff configuration) In this paper, the static lateral stability requirements and the lessons & learned of KC-100 airplane certification flight test results are shown.

• 한국표면공학회지
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• 제48권1호
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• pp.11-22
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• 2015

Pd alloy hydrogen membranes for hydrogen purification and separation need thermal stability at high temperature for commercial applications. Intermetallic diffusion between the Pd alloy film and the porous metal support gives rise to serious problems in long-term stability of Pd alloy membranes. Ceramic barriers are widely used to prevent the intermetallic diffusion from the porous metal support. However, these layers result in poor adhesion at the interface between film and barrier because of the fundamentally poor chemical affinity and a large thermal stress. In this study, we developed Pd alloy membranes having a dense microstructure and saturated composition on modified metal supports by advanced DC magnetron sputtering and heat treatment for enhanced thermal stability. Experimental results showed that Pd-Cu and Pd-Ag alloy membranes had considerably enhanced long-term stability owing to stable, dense alloy film microstructure and saturated composition, effective diffusion barrier, and good adhesive interface layer.

• 대한물리의학회지
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• 제13권4호
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• pp.35-42
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• 2018

PURPOSE: This study was conducted to investigate the effects of Kinesio taping and massage application to the calf muscles on ankle stability. METHODS: The study subjects were 66 healthy adults (male: 32, female: 34) who had no instability in their ankles. Subjects were randomly assigned to a Kinesio taping group or a massage group. The research tool used the Y-balance test to measure instability of the ankle. The distance between the right and left foot was measured from the center in the anterior, posterior-medial, and posterior-lateral directions. Massage was applied to the calf muscles three times over two weeks and Kinesio tape was attached to the calf muscle and tibialis anterior for 10 hours twice during the experimental period. RESULTS: The results showed that application of Kinesio taping resulted in increases in the distance between the feet increased in some directions. After the massage, the distance extended from the anterior and posterior-lateral directions was prolonged, and the ankle stability on the right and left sides was partially improved by massage application. CONCLUSION: Kinesio taping and massage applied to the calf muscles are appropriate interventions for the improvement of ankle stability. Based on the application times of massage, Kinesio taping appears to work more effectively for ankle stability.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 추계 학술발표회
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• pp.191-201
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• 2006

The flood control ability improvement project on existing dams is the project for prevention of disasters from excessive flood due to climate changes and thus protects lives and property damages by increasing safety of dams. The collapse of dam brings unimaginable disasters, so the project needs to be swiftly conducted by Government's funding. This paper introduces tile examples of the flood control ability improvement projects of multi-purpose and water supply dams, which is conducted in the way of structural measures among 26 dams operated by Kwater.

• Journal of the Korean Wood Science and Technology
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• 제44권3호
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• pp.457-476
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• 2016

본 연구에서는 목재의 열처리가공에 대하여, 문헌 연구를 통하여 이와 관련된 주요 이슈 및 기술 동향을 조사하였다. 산업적으로 이용되는 주요 열처리기술은 네덜란드의 Plato-process, 프랑스의 Retification process, 독일의 OHT-process, 및 핀란드의 Thermowood process 등이었다. 열처리 공정상의 주요 영향인자들은 대상 수종, 가열 온도, 시간, 열전달 매질(air, 증기, 진공, 질소, 오일 등)이며, 이들 인자들을 변수로 한 최적조건 탐색 등의 연구가 주류를 이룬다. 열처리 목재는 치수안정성 증가, 중량 및 강도 감소, 부후균에 대한 내후성 향상에 변이, 변색균 및 해충에 대해 불충분한 저항성 등의 특징을 가진다. 열처리 목재의 내후성 향상을 위해 각 수종에 적합한 열처리 공정과 처리조건 탐색의 필요성이 시사되었다. 지속가능한 환경보존 및 목재자원 절약을 위해 열처리 목재의 새로운 용도 개발 및 이용 확대 노력이 반드시 필요한 과제인 것으로 고찰되었다.

• KIEAE Journal
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• 제9권6호
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• pp.37-44
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• 2009

This study conducted an evaluation of the streetscape improvement project of the Gwangbok Street through analysis of correlations between psychological consciousness and physical elements in the street by comparing selected pictures of streetscape before and after the project. This work has conducted an analysis of Psychological characteristics by semantic differential method and an analysis of physical elements which influence psychological characteristics by regression analysis. According to the results of psychological analysis, the senses of interest, orderliness, esthetic and preference were highly improved in A district and the senses of openess, stability, orderliness were highly improved in B district. The results of analyzing physical elements influencing the improvement of these psychological consciousness in A district elucidated ; 1) the works of improving signboard and elevation of the building affected the whole these psychological consciousness, 2) the work of planting trees, making plant rests in the street improved the senses of orderliness, esthetic, 3) the work of changing finishing materials in the street enhanced the senses of esthetic, preference, 4) the work of adjusting the width between the road and the pavement, the work of improving traffic enhanced the senses of interest, preference. In the meantime in B district, the works of improving signboard and elevation of the building and those of planting trees, making plant rests in the street improved the senses of openess and orderliness. Also the work of improving traffic enhanced the senses of openess, stability and the work of expanding the pavement, that of changing finishing materials in the street improved the senses of openess, stability, orderliness.

• 토지주택연구
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• 제5권2호
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• pp.69-79
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• 2014

본 연구는 주거환경개선사업의 원주민 재정착보다 포괄적인 사업의 공공성 측면인 주거안정에 초점을 둔 것으로, 주거환경개선사업이 사업 전 후시점의 거주자(지구거주자, 재입주자, 신규입주자)의 주거안정에 어떠한 영향을 주었는지를 분석하였다. 분석을 위해 주거환경개선사업의 시행이전 지구, 시행완료된 준공지구에서 각각 다른 유형의 거주자들을 대상으로 설문조사를 실시하였다. 조사항목은 주거환경개선사업에 대한 주민인식과 주거안정 관련한 개별주택 내부의 물리적 환경 측면, 주거비용측면, 개별주택의 외부 주거환경 측면을 조사하였다. 주요 연구결과를 보면, 첫째, 주거환경개선 사업으로 인해 입주자들은 보다 젊은 층, 고학력, 고소득계층으로 변화하지만 가구구성과 장애여부, 직업구성에는 큰 변화가 없었다. 둘째, 주거환경 개선사업이 주거안정에 미친 영향을 보면 지구거자는 향후 주택의 물리적 여건과 주거외부환경은 양호해지나 주거비용에 대한 부담을 많이 호소하였다. 재입주자의 경우 주택면적과 방수는 증가하여 물리적 여건은 양호해지고 주거비용측면에서 비용증가, 주거외부환경은 양호해지는 형태를 보였다. 신규입주자는 주택의 물리적 여건인 주택면적이나 방수의 변화는 차이가 없고 주거비용은 상승, 외부환경은 양호해지는 형태를 보였다.

• Animal Bioscience
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• 제34권2호
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• pp.223-232
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• 2021

Objective: To investigate the improvement in utilization efficiency of total mixed ration (TMR) on Tibetan plateau, TMR were ensiled with different additives. Methods: A total of 150 experimental silos were prepared in a completely randomized design to evaluate the six treatments: i) control (without additive), ii) Lactobacillus buchneri (L. buchneri), iii) acetic acid, iv) propionic acid, v) 1,2-propanediol; and vi) 1-propanol. After 90 days of ensiling, silos were opened for fermentation quality and in vitro analysis, and then subjected to an aerobic stability test for 14 days. Results: Treating with L. buchneri, acetic acid, 1,2-propanediol and 1-propanol decreased propionic acid contents and yeast number, whereas increased (p<0.05) pH, acetic acid and ethanol contents in the fermented TMR. Despite increased dry matter (DM) loss in the TMRs treated with 1,2-propanediol and 1-pronanol, additives did not affect (p>0.05) all in vitro parameters including gas production at 24 h (GP24), GP rate constant, potential GP, in vitro DM digestibility and in vitro neutral detergent fibre digestibility. All additives improved the aerobic stability of ensiled TMR to different extents. Specially, aerobic stability of the ensiled TMR were substantially improved by L. buchneri, acetic acid, 1,2-propanediol, and 1-propanol, indicated by stable pH and lactic acid content during the aerobic stability test. Conclusion: L. buchneri, acetic acid, 1,2-propanediol, and 1-propanol had no adverse effect on in vitro digestibility, while ensiling TMR with the additives produced more acetic acid and ethanol, subsequently resulting in improvement of aerobic stability. There is a potential for some fermentation boosting additives to enhance aerobic stability of fermented TMR on Tibetan plateau.

• Tribology and Lubricants
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• 제30권1호
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• pp.9-14
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• 2014

In this Part II study, rotordynamic stability analyses were carried out to confirm improvements to the stability of a process high-speed lightweight centrifugal compressor, depending on the effects of tilting pad journal bearing designs. The bearing design variables considered were the clearances, LBPs, LOPs, and preloads. The results showed that the rotordynamic stability of the subject compressor rotor-bearing system improves exactly in accordance with the effects of the bearing design variables, which were determined in the preceding Part I study, owing to reduced bearing stiffnesses. Specifically, it was confirmed that the stability of the rotor system can be greatly improved by increasing both the machined and assembled bearing clearances, but there were no stability improvements by simply changing from an LBP to an LOP design. In addition, it was confirmed that for given fixed machined bearing clearances, the stability can be additionally improved by decreasing the preloads, i.e., by increasing the assembled clearances. In conclusion, it may be necessary to improve the designs of the original tilting pad bearings to obtain a sufficient margin of rotordynamic stability against a possible aerodynamic cross-coupled stiffness in a process high-speed centrifugal compressor. Thus, increasing the machined and assembled bearing clearances and decreasing the preload could be effective solutions.