• 제목/요약/키워드: back-analyses

검색결과 390건 처리시간 0.021초

유체클러치 터빈 날개의 유형별 유동해석에 대한 융합연구 (A Convergent Investigation on Flow Analysis by Type of Turbine Blade of Fluid Clutch)

  • 오범석;조재웅
    • 한국융합학회논문지
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    • 제11권3호
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    • pp.195-200
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    • 2020
  • 본 연구에서는 8개의 터빈 날개면들이 각각 추진축상에서 45°, 40°, 35°의 각도로 기울어져 있는 Model 1, 2 및 3인 3가지 Model의 유체클러치 터빈 날개 형상에 대한 유동 해석들을 수행하였다. 터빈 날개면이 추진축상에서 각도가 크게 기울어질수록 터빈 날개의 뒷면 이후에서의 흐름에서 Model들 중에서 가장 유동 압력을 크게 받고 있음을 알 수 있다. 반면에 터빈 날개면이 추진축상에서 각도가 작게 기울어질수록 유동 속도가 작게 된다. 터빈 날개면이 추진축상에서 각도가 작게 기울어질수록, 즉 유체의 흐름과 수직에 가까운 날개 형상이 효율적으로 유체클러치에 동력을 연결하고 차단하는데 있어서 적합함을 알 수 있다. 유체클러치 터빈 날개 유형별 유동해석을 적용함으로서 본 논문에서의 연구 결과는 미적인 설계를 적용할 수 있는 융합 연구자료로서 유리하다고 여겨진다.

고문헌 고찰을 통한 중국 가로수의 역사에 대한 연구 (A Study on the History of Chinese Roadside Tree through Old Literatures Review)

  • 종타오;안계복
    • 한국전통조경학회지
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    • 제36권1호
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    • pp.1-10
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    • 2018
  • 본 연구는 중국 가로수의 역사에 대한 체계적인 연구를 위하여 사상적 배경과 각 시대별 가로수의 식재 수종, 그리고 가로수의 관리제도 등에 대한 고문헌들의 분석을 수행하였으며 그 결과는 다음과 같다. 첫째, 춘추전국시대의 제자백가 가운데 노자, 장자, 묵자, 맹자, 관자의 사상이 중국의 수목과 가로수의 관리에 대한 근본적인 태도 형성에 영향을 미쳤다. 둘째, 시대별 가로수의 수종은 상이한 것으로 나타났으며, 그 중에 가장 많이 심겨진 수종은 버드나무류, 그 다음은 소나무류인 것으로 나타났다. 셋째, 주(周)나라 때부터 명나라에 이르기까지 복숭아나무와 자두나무 같은 유실수(有實樹)가 가로수로 많이 활용된 것으로 나타났다. 넷째, 가로수의 명칭과 가로수를 담당하던 관리는 시대별로 다른 것으로 나타났다. 다섯째, 현재 중국에 남아 있는 가장 오래된 가로수 유적으로는 약 2,000년이 된 사천성(四川省)의 검각취운랑을 들 수 있다.

PET/CT 영상에서의 표준섭취계수(SUV)의 신뢰성 확보를 위한 시스템별 차이에 관한 연구 : 초기 연구 (The Study of Difference on Each System for Reliance Security in SUV of PET/CT Images : Initial Study)

  • 박훈희;박민수;김정열;이승재;신희순;임한상;김세영;장혜원;오기백;김재삼;이창호
    • 대한디지털의료영상학회논문지
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    • 제10권1호
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    • pp.5-6
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    • 2008
  • In this study, using an experiment, in certified an error between each system of SUV (standardized uptake value) that is one of the main analyses to diagnose a tumor in PET/CT, so, it would assure reliability and help to diagnose any lesions accurately. That is, a detailed analysis progressed. as all images reconstructed every setting time, then, clinical reliability between each system was expressed numerically at MBq/mL and SUV. Therefore, this study is considered that flexibility of follow-up using diverse system was insured, and it helps to offer accurate and beneficial information for diagnosis of various fields.

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혁신클러스터의 성공 요인에 관한 연구 : 판교테크노밸리 사례를 중심으로 (A Study on the Success Factors of Innovation Cluster: A Case of the Pangyo Techno Valley in South Korea)

  • 정기덕;임종빈;정선양
    • 기술혁신학회지
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    • 제20권4호
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    • pp.970-988
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    • 2017
  • 혁신클러스터는 전 세계적으로 지역의 경쟁력을 높이는 주요 도구로 활용되고 있다. 한국도 정책적으로 다양한 형태의 혁신클러스터를 조성 및 육성하고 있다. 하지만 성공적인 혁신클러스터 육성을 위한 체계적인 분석은 활발하지 않은 실정이다. 본 연구에서는 문헌연구를 통해 혁신클러스터의 성공요인을 도출하고, 이를 활용하여 분석을 위한 프레임워크를 제시하였다. 또한 제시한 프레임워크에 따라 판교테크노밸리를 대상으로 사례연구를 하였다. 분석 결과 성공적인 혁신클러스터를 위해서는 혁신지향적인 환경, 지속적인 정책적 지원, 지식 네트워크의 활성화, 혁신성과의 환류가 중요한 것으로 나타났다.

적외선 램프를 이용한 비접촉식 태양전지셀 솔더링 장치 개발에 관한 연구 (A Study on the Development of Noncontact Soldering Device of PV Cells Using Infrared Lamp)

  • 노태정;김선진;박민용
    • 한국산학기술학회논문지
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    • 제14권1호
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    • pp.45-50
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    • 2013
  • Photopia를 활용하여 적외선 램프 반사부의 각 형상에 대한 조도 분포를 해석하여 최적인 원호 형상으로 설계하였다. 적외선 온도센서를 통해 태양전지셀의 솔더링 온도를 피드백 받아서 설정된 솔더링 온도 프로파일과의 오차를 제어값으로서 IR 램프의 전류를 실시간으로 제어하는 솔더링 온도의 폐루프 제어시스템을 구현하였다. HMI 조작반에 의해 쉽게 운전되고, PLC와 IR 램프 제어기에 의하여 강인하게 제어되는 IR 램프 열원을 사용한 태양전지셀의 비접촉식 솔더링 장치를 개발하였다.

Work-Related Musculoskeletal Disorders in Iranian Dentists: A Systematic Review and Meta-analysis

  • ZakerJafari, Hamid Reza;YektaKooshali, Mohammad Hossein
    • Safety and Health at Work
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    • 제9권1호
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    • pp.1-9
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    • 2018
  • Background: Work-related musculoskeletal disorders are the most important problems among professions particularly, dentists. This study was conducted to determine the prevalence of musculoskeletal disorders in various parts of the body in Iranian dentists by using systematic review and meta-analysis. Methods: This systematic review and meta-analysis was based on preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines and searching in national databases such as SID, Magiran, Irandoc, IranMedex, and Medlib, and international databases such as MedLine, Web of Sciences, Scopus, PubMed, ScienceDirect, Cochrane, Embase, Springer, Wiley Online Library, Ebsco, CEBM, and Google Scholar search engine which were published by January 1, 2017. Researched keywords were in Persian and their standard English equivalents were in accordance with their MeSH. The obtained documents were analyzed using Comprehensive Meta-analysis version 2. Results: According to 23 studies through 2,531 Iranian dentists which took part in this study, prevalence of skeletal disorders in Iranian dentists has been 17.6% [confidence interval (CI) 95%:11.7-25.5] in knees, 33.2% (CI 95%:24.1-43.8) in shoulders, 33.4% (CI 95%: 26.8-40.8) in the thorax, 51.9% (CI 95%:46.7-57.2) in necks, 33.7% (CI 95%:28.2-39.6) in wrists/hands, 12.9% (CI 95%:7.7-20.6) in elbows, 37.3% (CI 95%: 31.5-43.5) in lower back, 11.9% (CI 95%:8.7-16.1) in thighs, 12.9% (CI 95%:3.8-36) in the foot, and 10.5% (CI 95%:7-15.4) in legs. Conclusion: Considering the high prevalence of musculoskeletal disorders in Iranian dentists, ergonomics should be included as a lesson in preclinic and also, reeducation courses for ergonomics basics should be executed for graduate dentists.

죽엽과 연잎 분말을 첨가한 밀 복합분의 물성에 관한 연구 (Study on the Rheological Characteristics of the Mixed Wheat Flour Containing Bamboo and Lotus Leaf Powder)

  • 황성연;오금자;강근옥
    • 한국식생활문화학회지
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    • 제29권4호
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    • pp.355-363
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    • 2014
  • The purpose of this study was to investigate the rheological characteristics of medium wheat flour mixed with bamboo leaf and lotus leaf powders. Rheological properties of the mixed flours were tested based on falling number, color, RVA, farinogram, and rheofermentometer analyses. Falling numbers increased with addition of bamboo leaf and lotus leaf powders. The L values of all mixed flours were less than that of control. The 1% mixed flour sample containing bamboo leaf and lotus leaf powders was not significantly different from 3% mixed flour. The a values of the mixed flour decreased as bamboo and lotus powders increased, whereas b values increased. Addition of bamboo leaf and lotus leaf powders to flour reduced peak viscosity, holding strength, and final viscosity. The set back values of mixed wheat flour containing bamboo leaf powder were lower than those of mixed wheat flour containing lotus leaf powder, suggesting that bamboo leaf powder suppressed retrogradation of flour compared to lotus leaf powder. In the farinogram, the water absorption and consistency of the flours containing bamboo and lotus leaf powders increased, whereas development time and stability decreased. The fermentation time of dough with lotus leaf powder was less than that of dough with bamboo leaf powder.

A simple damper optimization algorithm for both target added damping ratio and interstorey drift ratio

  • Aydin, Ersin
    • Earthquakes and Structures
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    • 제5권1호
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    • pp.83-109
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    • 2013
  • A simple damper optimization method is proposed to find optimal damper allocation for shear buildings under both target added damping ratio and interstorey drift ratio (IDR). The damping coefficients of added dampers are considered as design variables. The cost, which is defined as the sum of damping coefficient of added dampers, is minimized under a target added damping ratio and the upper and the lower constraint of the design variables. In the first stage of proposed algorithm, Simulated Annealing, Nelder Mead and Differential Evolution numerical algorithms are used to solve the proposed optimization problem. The candidate optimal design obtained in the first stage is tested in terms of the IDRs using linear time history analyses for a design earthquake in the second stage. If all IDRs are below the allowable level, iteration of the algorithm is stopped; otherwise, the iteration continues increasing the target damping ratio. By this way, a structural response IDR is also taken into consideration using a snap-back test. In this study, the effects of the selection of upper limit for added dampers, the storey mass distribution and the storey stiffness distribution are all investigated in terms of damper distributions, cost function, added damping ratio and IDRs for 6-storey shear building models. The results of the proposed method are compared with two existing methods in the literature. Optimal designs are also compared with uniform designs according to both IDRs and added damping ratios. The numerical results show that the proposed damper optimization method is easy to apply and is efficient to find optimal damper distribution for a target damping ratio and allowable IDR value.

In vivo와 In vitro 평가모델을 利用한 韓藥抽出物의 毛髮成長 및 促進에 미치는 實驗的 硏究 (Extracts for the Hair Growth Stimulation using In vivo and In vitro Test Models)

  • 강학천;이수형;김남권;임홍진;황충연
    • 한방안이비인후피부과학회지
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    • 제15권2호
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    • pp.53-79
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    • 2002
  • To screen the effective materials for hair loss treatment, several natural extracts were tested using in vivo and in vitro test models. Firstly, all test materials were applicated onto the back skin of C57BL/6 mouse and then hair growth promoting effect was measured using hair growth index. As a result, Prunus mume, black bean, Brassica campestris subsp. black sesame and Rubi Fructus showed potent hair growth promoting effect, ranking as 1.5-2.0 of hair growth index. However, there were no plant extracts, which have remarkable potential of growth promotion of human hair dermal papilla cells cultured in vitro. In the experiments of 5${\alpha}$-reductase type Ⅱ inhibition assay, Prunus mume, Eriobotryae Folium showed effective potential to inhibit the activity of 5${\alpha}$-reductase type Ⅱ. To investigate the possible involvement of the effect of several plant extracts on the gene expression of growth factors in human hair dermal papilla cells, RT - PCR analyses were performed. However, there were no plant extracts, which have profound effect on the gene expression of several growth factors such as IGF-I, KGF, HGF and VEGF in the dermal papilla cells. Another tests for inhibition of microbial such as P. acne were also carried out to find whether these plant extracts have anti -microbial activities. Rubi Fructus showed anti -microbial effects on Propionibacterium acnes, which is believed as a pathogen of acne. Together, these results showed several plant extracts can be used for hair growth promotion.

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數種의 韓藥材가 毛髮成長에 미치는 影響 (Studies on the effects of medicinal plant extracts on the hair growth stimulation)

  • 최웅;최정화;김종한
    • 한방안이비인후피부과학회지
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    • 제15권2호
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    • pp.80-103
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    • 2002
  • To screen the effective materials for hair loss treatment, several natural extracts were tested using in vivo and in vitro test models. Firstly, all test materials were applicated onto the back skin of C57BL/6 mouse and then hair growth pormoting effect were measured using hair growth index As a result, Polygonum muitifiorum Thunb and Terrninalia chebula Retz. showed potent hair growth promoting effect, ranking as 1.5-2.0 of hair growth index. However, there were no plant extracts, which have remarkable potential of growth promotion of human hair dermal papilla cells cultured in vitro. In the experiments of 5${\alpha}$-reductase type Ⅱ inhibition assay, Morus alba L., Chaenomelis Fructus, Saussureae Radix, Angelicae Gigantis Radix, Polygonum multifiorum Thunb, and Angelica dahurica (Fischer) Bentham et Hooker f. showed effective potential to inhibit the activity of 5${\alpha}$-reductase type Ⅱ. To investigate the possible involvement of effects of several plant extracts on the gene expression of growth factors in human hair dermal papilla cells, RT-PCR analyses were performed. As a consequences, Mentha haplocalyx Briq., Cimicifuga foetida L., Eclipta prostrata (L.) L., Pinus densiflora S. et. Z, and Polygonum muitifiorum Thunb revealed the regulatory roles on the expression of growth factors such as IGF-I, KGF, HGF and VEGF in the dermal papilla cells. Another test for inhibition of microbial such as P. acne and P. ovale were also carried out to find whether these plant extracts have anti-microbial activities. Morus alba L. and Chaenomelis Fructus showed anti-microbial effects on Propionibacterium acnes, which is believed as a pathogen of acne. Together, these results showed several plant extracts can be used for hair growth promotion.

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