• 제목/요약/키워드: Material heterogeneity

검색결과 78건 처리시간 0.022초

Characteristics of Warm Acupuncture Reported in Experimental Studies: A Descriptive Narrative Review

  • Choi, Ji Won;Choi, Seo Young;Lee, Ji Sun;Yang, Gi Young
    • Journal of Acupuncture Research
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    • 제36권3호
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    • pp.131-139
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    • 2019
  • Background: This study aimed to investigate the correlation between heat transmission and intervention factors for warm acupuncture (such as features of acupuncture material and moxa, the treatment method, and clinical symptoms). Methods: Korean, English, Chinese and Japanese databases were analysed. Experimental studies that explored the association between thermal stimulation delivery and warm acupuncture intervention factors were included. The peak temperature, time to reach the peak temperature, and time of the effective stimulus, were set as the major parameters and analysed. Results: A total of 12 studies were included. Two studies were associated with the acupuncture needle material, 4 studies associated with the moxa mass, 1 study associated with the moxa density, 2 studies associated with the location of ignition, and 1 study associated with treatment environment were reviewed. The reporting quality of the 12 studies was low. Conclusion: This study provided limited information because of the heterogeneity of materials and parameters depending on each experiment. Further studies should clarify the correlation between heat transmission and intervention factors for warm acupuncture.

과학기술-사회과학 연계모형의 모색 (On the Interdisplinary Linkage Framework between Engineering Discipline and Social Science Discipline)

  • 박용태
    • 기술경영경제학회:학술대회논문집
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    • 기술경영경제학회 1997년도 제12회 동계학술발표회 논문집
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    • pp.70-88
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    • 1997
  • Recently, the interdisciplinary linkage between engineering and social science has received an increasing attention as an emerging education discipline. Due to intrinsic complexity of innovation process and heterogeneity of disciplinary nature, however there exists little, if not no, effort to draw a common framework in terms of educational scope and contents of the new subject. This paper presents a number of criteria and guidelines for building up new educational framework by integrating engineering subject and social science subject. Specifically, three neo-disciplines, technology policy, technology management, and economics of technology are considered since it is postulated that the forementioned disciplines have established academic identity and fundamental structure By nature, this paper is an exploratory and seminal one. It is not the purpose of this paper to provide a concrete table of contents of educational material. Instead, it merely brings up a discussion topic for the wide audience of academic arena, leaving the gradual consensus and convergence as future task.

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Three-dimensional numerical simulation and cracking analysis of fiber-reinforced cement-based composites

  • Huang, Jun;Huang, Peiyan
    • Computers and Concrete
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    • 제8권3호
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    • pp.327-341
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    • 2011
  • Three-dimensional graphic objects created by MATLAB are exported to the AUTOCAD program through the MATLAB handle functions. The imported SAT format files are used to produce the finite element mesh for MSC.PATRAN. Based on the Monte-Carlo random sample principle, the material heterogeneity of cement composites with randomly distributed fibers is described by the WEIBULL distribution function. In this paper, a concept called "soft region" including micro-defects, micro-voids, etc. is put forward for the simulation of crack propagation in fiber-reinforced cement composites. The performance of the numerical model is demonstrated by several examples involving crack initiation and growth in the composites under three-dimensional stress conditions: tensile loading; compressive loading and crack growth along a bimaterial interface.

철근콘크리트 유공 깊은 보에 대한 해석적 연구 (Analytical study on Reinforced Concrete Deep Beams with Opening)

  • 이석주;이종권;이병해
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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    • pp.587-592
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    • 2000
  • As the residential spaces become high-rised and high-density, Multi-story buildings were constructed with transfer girders, Deep beams, wall foundations, floor diaphragms an shear walls which may have column offsets. Especially, In the analysis and design of Multi-story buildings, the lateral loads must be taken into account. But, there have been no appropriate theory and national design code for predicting ultimate shear strength of reinforced concrete Deep beams with web opening. Only empirical and semi-empirical formulas for predicting their ultimate load bearing capacities due to the complexities of the structural non-linearity and material heterogeneity. So this study analyze tow-dimensional finite element model that represents exactly the behavior of real structures with SBETA which are general nonlinear finite element analysis program, and compare the results with that from the real reinforced Concrete Deep beams with web opening tests. From the comparison, and parametric study, The Study presents the elementary data of the earthquake resistance for the reinforced concrete Deep beams with web opening.

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Assessing the Impact of Locally Produced Aerosol on the Rainwater Composition at the Gosan Background Site in East Asia

  • Han, Yeongcheol;Huh, Youngsook
    • Asian Journal of Atmospheric Environment
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    • 제8권2호
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    • pp.69-80
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    • 2014
  • It is often assumed that atmospheric observations at remote sites represent long-range transport of airborne material, and local influences are overlooked. We evaluated the impact of local input on the rainwater composition at Gosan Station, a strategic site for monitoring the continental outflow from Asia. We analyzed a 14-year record of rainwater chemical composition archived by the Korea Meteorological Administration and detected local terrestrial contribution for nitrate, sulfate and ammonium. We also measured the chemical composition of rainwater sampled simultaneously at multiple locations within the premises of the Gosan Station, from which local influence with meter-scale spatial heterogeneity could be discerned. We estimate that the local input accounted for at least ~10% of the wet deposition of nitrogen and ~12% of the wet deposition of sulfur during the 14 years. This highlights the significance of the local influence, which should be carefully assessed when interpreting atmospheric observations at this site.

Hierarchical multiscale modeling for predicting the physicochemical characteristics of construction materials: A review

  • Jin-Ho Bae;Taegeon Kil;Giljae Cho;Jeong Gook Jang;Beomjoo Yang
    • Computers and Concrete
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    • 제33권3호
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    • pp.325-340
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    • 2024
  • The growing demands for sustainable and high-performance construction materials necessitate a deep understanding of their physicochemical properties by that of these heterogeneities. This paper presents a comprehensive review of the state-of-the-art hierarchical multiscale modeling approach aimed at predicting the intricate physicochemical characteristics of construction materials. Emphasizing the heterogeneity inherent in these materials, the review briefly introduces single-scale analyses, including the ab initio method, molecular dynamics, and micromechanics, through a scale-bridging technique. Herein, the limitations of these models are also overviewed by that of effectively scale-bridging methods of length or time scales. The hierarchical multiscale model demonstrates these physicochemical properties considering chemical reactions, material defects from nano to macro scale, microscopic properties, and their influence on macroscopic events. Thereby, hierarchical multiscale modeling can facilitate the efficient design and development of next-generation construction.

상업공간에서 재료를 통한 공간의 컨버전 소통 방법 연구 - 2008~2012년 국내·외 상업공간을 중심으로 - (A Study on Space of Conversion Communication Method through Materials in Commercial Space - Focusing on Domestic and International Commercial Spaces in 2008~2012 -)

  • 지주연;서지은
    • 한국실내디자인학회논문집
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    • 제22권2호
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    • pp.194-202
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    • 2013
  • Commercial spaces are very sensitive in terms of trend and uniqueness, and many elements expressing space coexist together with brilliant ideas aiming to attract consumer attention and even induce sudden desire of purchase. Coexistence in space is expressed in various ways and out of those ways, representation by material is especially apparent. The application of material does not individually influence the expression of space, but the characteristics of multiple materials applied contribute to the distinction of space through mutual communication. This study intends to analyze how conversion is centered to express the distinction of space through materials communicated in space. The detailed study results are as follows. First, the conversion expression method of material resulted as 'Substitution', 'Contrast', 'Assimilation', 'Creation'. These four was divided and analyzed into 'Time', 'Space', 'Genre'. As a result of this analysis, such significances were shown as 'Contrast' in 'Time', 'Substitution' in 'Space', and 'Assimilation' in 'Genre'. Second, the conflict due to heterogeneity by conversion of 'Contrast' in 'Time' through past and current materials appeared to induce interest amongst consumers. Third, within 'Space', 'Substitution' of natural/artificial materials was noticeably applied. This is evaluated as a constructive way of expressing natural forms into artificial forms further intending to provoke attention and stimulate emotion. Fourth, in conversion through 'Assimilation' in 'Genre', rather than using materials only from other areas, synchronizing it by combining architectural materials is an effective method. Such results are thought to be a distinctive design method that draws attention of customers by communicating disparate materials in commercial space. Thus, the study results are expected to be utilized as an elementary resource in designing commercial space with character and high satisfaction.

염석법을 이용한 비공유 기능기화된 그래핀 나노플레이트렛의 분리 공정 연구 (Separation of Non-covalently Functionalized Graphene Nanoplatelets via Salting-out Process)

  • 김준희;유승찬;차재민;류호진;홍순형
    • Composites Research
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    • 제32권3호
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    • pp.134-140
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    • 2019
  • 그래핀 나노플레이트렛(GNP)은 현시점에서 가장 산업화 적용에 가까운 그래핀으로 알려져 있다. 하지만 현재 GNP는 그 우수한 생산량에도 불구하고 응집현상과 물리화학적 불균질성으로 인해 복합재에서의 강화재로 사용되기에는 제한이 존재한다. 본 연구에서는 이러한 GNP의 문제 해결을 위해 산업화 레벨의 대량생산 공정으로 확장 가능한 비공유 기능기화공정을 이용하여 GNP를 기능기화하였다. 본 기능기화 공정은 저렴한 물질로 알려진 멜라민을 사용하여 GNP의 응집현상을 방지하는 동시에 극성 용매내에서의 분산성을 향상시켰다. 뿐만 아니라 기능기화된 GNP의 분산성의 차이를 이용한 염석법 공정을 적용, GNP를 크기 별로 정제하였다. 이처럼 본 연구는 언급한 기능기화와 분리 공정을 기반으로 하여 GNP의 복합소재/부품 산업 응용을 위한 전략을 제시하였다.

해수 침투에 대한 층상 불균질성 및 지하수 양수 방식의 영향 삼차원 수치 모의 (Three-Dimensional Numerical Simulation of Impacts of Layered Heterogeneity and Groundwater Pumping Schemes on Seawater Intrusion)

  • 박화석;김중휘;염병우;김준모
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제13권4호
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    • pp.8-21
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    • 2008
  • 지질 매체의 층상 불균질성과 지하수 양수 방식이 해안 대수층 내에서의 지하수 유동과 염분 이동에 미치는 영향을 정량적으로 분석하기 위하여 수리동역학적 분산 수치 모델을 이용한 일련의 삼차원 수치 모델링이 수행되었다. 해수 침투에 대한 층상 불균질성의 영향을 평가하기 위하여 하부 사토층(대수층)과 상부 점토층(준대수층)으로 구성된 층상 불균질 해안 대수층과 이에 상응하는 등가의 물질로 구성된 균질 해안 대수층을 수치 모델링하였다. 또한 해수 침투에 대한 지하수 양수 방식의 영향을 평가하기 위하여 전체 수치 모델링 기간 동안에 동일한 양의 지하수를 양수하는 연속적인 지하수 양수 방식과 두 개의 주기적인 지하수 양수 방식을 상기한 두 해안 대수층에 적용하였다. 수치 모델링 결과는 주기적인 지하수 양수 방식이 층상 대수층의 하부 사토층뿐만 아니라 상부 점토층에서의 지하수 유동과 염분 이동에 보다 중대한 악영향을 끼치며, 주기적인 지하수 양수 시에 양수 강도가 클수록 지하수 염수화가 공간적 및 시간적으로 더욱 심화됨을 보여준다. 이는 해수 침투에 의한 지하수 염수화를 최소화하기 위해서는 지속적인 지하수 양수 방식이 보다 더 적합할 수 있음을 의미한다. 또한 수치 모델링 결과는 주기적인 지하수 양수시에 상부 점토층에서의 지하수 염수화 양상이 하부 사토층에서의 그것에 비해 매우 다르게 발생함을 보여준다. 이러한 두 지층 사이의 지하수 염수화 양상의 차이는 층상 해안 대수층의 층상 불균질성에 기인하는 것으로 해석된다.

Deep proximal margin rebuilding with direct esthetic restorations: a systematic review of marginal adaptation and bond strength

  • Hoda S. Ismail;Ashraf I. Ali;Rabab El. Mehesen;Jelena Juloski;Franklin Garcia-Godoy;Salah H. Mahmoud
    • Restorative Dentistry and Endodontics
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    • 제47권2호
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    • pp.15.1-15.18
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    • 2022
  • This review aimed to characterize the effect of direct restorative material types and adhesive protocols on marginal adaptation and the bond strength of the interface between the material and the proximal dentin/cementum. An electronic search of 3 databases (the National Library of Medicine [MEDLINE/PubMed], Scopus, and ScienceDirect) was conducted. Studies were included if they evaluated marginal adaptation or bond strength tests for proximal restorations under the cementoenamel junction. Only 16 studies met the inclusion criteria and were included in this review. These studies presented a high degree of heterogeneity in terms of the materials used and the methodologies and evaluation criteria of each test; therefore, only a descriptive analysis could be conducted. The included studies were individually evaluated for the risk of bias following predetermined criteria. To summarize the results of the included studies, the type of restorative material affected the test results, whereas the use of different adhesive protocols had an insignificant effect on the results. It could be concluded that various categories of resin-based composites could be a suitable choice for clinicians to elevate proximal dentin/cementum margins, rather than the open sandwich technique with resin-modified glass ionomers. Despite challenges in bonding to proximal dentin/cementum margins, different adhesive protocols provided comparable outcomes.