In the present study, domain evolution processes of a near-morphotropic PZT ceramic during poling was studied using vertical piezoresponse force microscopy (PFM). To perform macroscopic poling in bulk polycrystalline PZT, poling was carried out in a stepwise fashion, and PFM scan was performed after unloading the electric field. To identify the crystallographic orientation and planes for the observed non-180o domain walls in the PFM images, compatibility theory and electron backscatter diffraction (EBSD) were used in conjunction with PFM. Accurate registration between PFM and the EBSD image quality map was carried out by mapping several grains on the sample surface. A herringbone-like domain pattern consisting of two sets of lamellae was observed; this structure evolved into a single set of lamellae during the stepwise poling process. The mechanism underlying the observed domain evolution process was interpreted as showing that the growth of lamellae is determined by the potential energy associated with polarization and an externally applied electric field.

본 연구에서는 발광층의 전자와 정공의 재결합 영역을 확인하고, 단계적 도핑구조를 이용하여 여기자들의 효율적인 분배를 통해 roll-off 효율을 감소시켜서 녹색 인광 유기발광다이오드의 수명 증가 를 나타냈다. 발광층 내 호스트는 양극성의 4,4,N,N'-dicarbazolebiphenyl (CBP)를 사용하여 전하의 이 동을 원활하게 하였다. 발광층을 네 구역으로 분할하여 각각 소자를 제작하였고, 네 구역의 도판트 농도 에 따라 발광효율과 수명 향상을 보였다. 이로써 발광층 내의 단계적 도핑구조를 이용하여 캐리어와 여 기자들이 원활하게 분배된 것을 확인하였다. 기준소자 대비 발광층의 도판트 농도를 5, 7, 11, 9% 순서 로 단계적 도핑구조를 적용한 device C의 수명이 약 73.70% 증가하였고, 휘도 효율은 51.10 cd/A와 외 부 양자 효율은 14.88%의 성능을 보였다.

  본 논문에서는 운송비용과 재고유지비용의 합을 최소화하는 것을 목적으로 유한 계획기간 동안의 수요를 충족시키는 동적 랏사이징 문제를 다룬다. 운송비용을 고려하는 기존의 랏사이징 모형들과는 달리 운송 트럭의 대수에 따라 계단형으로 운송비용이 증가하는 경우를 다루고 있다. 이 문제를 선형정수모형으로 모델링하며 그리디 방식의 휴리스틱을 제안한다. 제안된 휴리스틱의 성능을 평가하기 위해 계산실험을 수행하며, 그 결과 매우 짧은 시간 안에 최적해에 가까운 해를

As quality becomes a primary leading factor of organizational success, various management strategies have been In-troduced to Improve quality competitiveness Quality competitiveness, however, is difficult to measure and numerous organ-izations are struggl

항만의 주요 정책 및 향후 운영계획 수립 시 정확한 물동량 예측에 관한 연구는 매우 중요하며 이러한 중요성으로 인해 관련 연구가 활발히 수행되고 있다. 본 논문에서는 국내 최대 석탄 및 철광석 처리 항만인 광양항을 대상으로 단계적 회귀분석과 인공신경망모형을 활용하여 모형간 예측력을 비교하였다. 2009년 1월부터 2019년 1월까지 총 121개월의 월별자료를 활용하였으며 석탄 및 철광석 물동량에 영향을 주는 요인을 선정하여 공급관련요인과 시장·경제관련요인으로 분류하였다. 단계적 회귀분석 결과, 광양항 석탄 물동량 예측모형의 경우, 입항선박 톤수, 석탄가격 및 대미환율이 최종변수로 선정되었고 철광석 물동량 예측모형의 경우, 입항선박 톤수, 철광석가격이 최종변수로 선정되었다. 인공신경망모형의 경우, 모델 성능에 영향을 미치는 다양한 Hyper-parameters를 조정하며 최적 모델을 선정하는 시행착오법을 사용하였다. 분석결과 인공신경망모형이 단계적 회귀분석에 비해 우수한 예측성능을 나타내었으며 예측 모형별 예측값과 실측값을 그래프 상 비교 시에도 인공신경망모형이 단계적 회귀분석에 비해 고·저점을 유사하게 나타냈다.

This study was to investigate the improvement of immune activities of the extracts from Codonopsis lan-ceolata by stepwise steaming process and high pressure process. The phenol contents was 8.742㎍/㎎ which was higher thanthat from conventional extraction using 70% ethyl alcohol at 80℃ for 24hours. All of extracts at a concentration of 1.0㎎/㎖showed relatively low cytotoxicity on human normal kidney cell (HEK293) in range of 16 19%. The immune B and T cellgrowth was improved by extracts using the steamed and high pressure precess of C. lanceolata up to 180×10⁴cells/㎖ and96×10⁴cells/㎖, respectively. The extract prepared also greatly increased the secretion of both IL-6 and TNF-α from thestepwise steamed and high pressure process. This results can conclude that stepwise steamed and high pressure processeffectively released active biomaterials which could important role in enhancing immune activity in the body.

The purpose of this study is to examine the effects of the rural community planning focusing on the stepwise empowerment system in Jinan-gun, Jeollabuk-do province. This paper also tries to examine how this system affect the awareness for community planning and empowerment of the residents. The satisfaction of the people who join this program were also investigated. The subjects of the research were divided into two groups. Group A consisted of the people who join the system from the first stage, and group B consisted of the people who joined the fourth stage directly. The differences of the recognition, capability changes and satisfaction between two groups were compared and analyzed by questionnaires. The results of this research can be summarized as follows. The first, group A recognized the community planning system in Jinan-gun more positively than group B. They thought that it's very useful and beneficial for their community and this system should be continued further. The second, group A considered that they achieved bigger advancement in community design capabilities in terms of personal, relational and social aspects than group B. In addition, group A also showed higher satisfaction for rural community planning than group B. Based on the results, alternatives for rural community planning were drawn as follows. The first, considering that group A showed more positive responses, starting from the first stage is more stable way to succeed in rural community planning. Which means the critical condition of community design is not the community business but the improving the public awareness and community mind. The second, it's considered that the number of participation is proportional to the advancement of capability in community project, so improving residents' opportunity to participation in community design might be effective. The third, community leader is another critical condition. It is needed to pay more attention to the education for the rural community leader with good experience and capability of community affairs.

In general, stepwise hot steaming process is known to be effective in improving its biological activities; however, not much employed in processing Codonopsis lanceolata due to its hardness. The complex processed C. lanceolata showed highest free radical scavenging acitivity as 45.21%. Total phenol and flavonoid content were of complex processed C. lanceolata higher than conventional extract and alone steaming process. It was showed the lower melanogenesis rate on melanin production test by B16F10 cells as 27.46%. High inhibitory of tyrosinase was also measured as 28.61% by adding steamed Codonopsis lanceolata extracts by high pressure extraction of 1.0 mg/ml. And anti-wrinkle activity were 39.08%. In comparing phenolic acids profiles in the extract, in general higher amounts of polyphenol were obtained possibly by easy release of active components during thermal processing, which results in better antioxidant activities than that of general extract. This findings can also be supported by result that the extract by steaming process showed better activities than the general extraction extract.

In general, stepwise hot steaming process is known to be effective in improving its biological activities; however, not much employed in processing Codonopsis lanceolata due to its hardness. In this study, C. lanceolata was first pretreated with warm water at 50℃ and 60℃ for two hours, then steamed for 3 hours. Antioxidant activities of 70% ethanol extracts were compared with the extract from the water solvent: 41.58% vs 8.98% of DPPH radical scavenging activity in adding 1.25mg/ml of steamed extract and water extract, respectively. Reducing power of steamed and fresh C. lanceolata were also measured as 1.39 and 0.71. Total poly phenolic of the steamed extract was estimated as 12.11mg/g, compared to 3.98mg/g fresh C. lanceolata. Total flavonoid contents were also obtained as 11.48mg/g, compared to 7.11mg/g of fresh C. lanceolata. In comparing phenolic acids profiles in the extract, in general higher amounts of gallic acid, trans-ferulic acid, vanillic acid were obtained possibly by easy release of active components during thermal processing, which results in better antioxidant activities than that of water extract. This findings can also be supported by result that the ethanol extract showed better activities than the water extract.

본 연구는 다단계 온도프리스트레싱 공법으로 보강된 합성보의 하중재하 실험 및 구조해석을 통하여 온도프리스트레싱 공법의 프리스트레스 도입효과와 단면증가효과를 평가하였다. 연구결과 온도프리스트레싱을 이용한 합성보의 보강공법은 온도프리스트레싱에 의한 프리스트레스 도입 뿐 아니라 커버플레이트의 설치에 의한 단면증가로 합성보의 처짐 또한 감소시킬 수 있으므로 합성보의 효율적인 보강공법으로 적용이 가능할 것이다.

다단계 온도프리스트레싱 공법은 기존의 프리스트레싱 공법과 단면접합공법의 장점을 이용한 새로운 개념의 프리스트레싱 공법으로 프리스트레싱용 커버플레이트를 다단계로 가열하여 거더의 하부플랜지에 고장력볼트로 접합한 뒤, 열원을 제거하여 발생하는 다단계 수축력을 보강에 필요한 프리스트레싱력으로 이용한 공법이다. 본 연구는 다단계 온도프리스트레싱 공법의 실제적인 적용성 평가를 위하여 다단계 가열을 위한 가열장비의 가열성능 평가 실험을 실시하였으며, 라멘형 강거더 임시교량을 제작하고 다단계 온도프리스트레싱 공법을 적용하여 도입 프리스트레싱력을 확인하였다. 또한, 트럭을 이용한 하중재하 실험을 실시하여 구조해석 결과와 비교하였다.