• Title/Summary/Keyword: Macroscopic Characteristics

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An Observation on the Concept of Shape Grammar through the Body Proportion of the Mid-size Sedans (중형 세단의 차체 비례를 통한 자동차 조형문법의 개념고찰)

  • Koo, Sang
    • Archives of design research
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    • v.18 no.2 s.60
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    • pp.283-292
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    • 2005
  • Recently automotive markets are on the way into maturing status with the mega merger between makers which brought equalizations of technology and upgrade of overall performance of vehicles. And the needs of automobile also changed into replacement buying from the entry buying. For the reason why it is the recent trend which has more importance on the software oriented element such as the sane design of vehicles than the hardware like the mechanical elements. This changing characteristics of market which requires more creativity and finished style treatment on an automotive design demand the concept of shape grammar for conducting shape on the macroscopic view. In this research the possibility has been observed to use the body proportion as the concept of the shape grammar for analyzing the relations between the form, sign, and perception as a basic principle of organizing shapes.

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The origins and evolution of cement hydration models

  • Xie, Tiantian;Biernacki, Joseph J.
    • Computers and Concrete
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    • v.8 no.6
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    • pp.647-675
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    • 2011
  • Our ability to predict hydration behavior is becoming increasingly relevant to the concrete community as modelers begin to link material performance to the dynamics of material properties and chemistry. At early ages, the properties of concrete are changing rapidly due to chemical transformations that affect mechanical, thermal and transport responses of the composite. At later ages, the resulting, nano-, micro-, meso- and macroscopic structure generated by hydration will control the life-cycle performance of the material in the field. Ultimately, creep, shrinkage, chemical and physical durability, and all manner of mechanical response are linked to hydration. As a way to enable the modeling community to better understand hydration, a review of hydration models is presented offering insights into their mathematical origins and relationships one-to-the-other. The quest for a universal model begins in the 1920's and continues to the present, and is marked by a number of critical milestones. Unfortunately, the origins and physical interpretation of many of the most commonly used models have been lost in their overuse and the trail of citations that vaguely lead to the original manuscripts. To help restore some organization, models were sorted into four categories based primarily on their mathematical and theoretical basis: (1) mass continuity-based, (2) nucleation-based, (3) particle ensembles, and (4) complex multi-physical and simulation environments. This review provides a concise catalogue of models and in most cases enough detail to derive their mathematical form. Furthermore, classes of models are unified by linking them to their theoretical origins, thereby making their derivations and physical interpretations more transparent. Models are also used to fit experimental data so that their characteristics and ability to predict hydration calorimetry curves can be compared. A sort of evolutionary tree showing the progression of models is given along with some insights into the nature of future work yet needed to develop the next generation of cement hydration models.

Manufacturing of Cu Repair Coating Material Using the Kinetic Spray Process and Changes in the Microstructures and Properties by Heat Treatment (Kinetic spray 공정을 이용한 Cu repair 코팅 소재 제조 및 열처리에 따른 미세조직과 물성 변화)

  • Jeon, Min-Gwang;Kim, Hyung-Jun;Lee, Kee-Ahn
    • Journal of Powder Materials
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    • v.21 no.5
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    • pp.349-354
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    • 2014
  • This study is a basic research for repair material production which manufactured a Cu repair coating layer on the base material of a Cu plate using kinetic spray process. Furthermore, the manufactured material underwent an annealing heat treatment, and the changes of microstructure and macroscopic properties in the Cu repair coating layer and base material were examined. The powder feedstocks were sphere-shaped pure Cu powders with an average size of $27.7{\mu}m$. The produced repair coating material featured $600{\mu}m$ thickness and 0.8% porosity, and it had an identical ${\alpha}$-Cu single phase as the early powder. The produced Cu repair coating material and base material displayed extremely high adhesion characteristics that produced a boundary difficult to identify. Composition analysis confirmed that the impurities in the base material and repair coating material had no significant differences. Microstructure observation after a $500^{\circ}C/1hr$. heat treatment (vacuum condition) identified recovery, recrystallization and grain growth in the repair coating material and featured a more homogeneous microstructure. The hardness difference (${\Delta}H_v$) between the repair coating material and base material significantly reduced from 87 to 34 after undergoing heat treatment.

The Trend and Issues of the Gerontological Nursing Study in Korea (국내 노인간호연구 분석과 발전방향)

  • 이영란;김신미;박혜옥;박효미;조계화;노유자
    • Journal of Korean Academy of Nursing
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    • v.28 no.3
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    • pp.676-694
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    • 1998
  • Issues related to the elderly have been recognized in Korea and nursing schalors have tried to study these issues. It is hard to say which the direction we, are going or have to go, since there has been little systemic effort to establish gerontological nursing field yet. Therefore, it is necessary to find out the trend and the guidelines of gerontolotical nursing studies for the future. Dissertation and published articles related to the elderly in the nursing field from 1991 to the Feburary of 1997 were are reviewed. Total 127 studies were analysed in terms of concept, design/methodology, and results, and the nature and issues of the gerontologic nursing studies in Korea were explored. The results are as follows : 1. There was no clear chronological definition of the elderly. 2. The most popular research design was an exploratory/descriptive study. 3. The major concepts studied were physical and mental health. 4. Among those studies using instruments which were developed and modified and/or translated by researchers, the reliability and validity were rarely reported. 5. Theory based studies were rare. We suggest the following issues for future studies : 1. The chronological and other criteria related to the defition of elderly is needed. 2. Physiopsychosocial characteristics of Korean elderly and their mangements in terms of intervention studies need to be conducted more systemically. 3. Social issues from the change of types and functions of family such as single elderly family need to be studied. 4. Participation in and collaborate with other disciplins are needed. 5. Development and test of instruments to measure phenomena or concepts is needed. 6. Macroscopic approach such as policy also needed. 7. Theory based studies are needed.

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The Location Patterns of Company-affiliated Research and Development Institutes (기업부설연구소의 공간적 입지 유형)

  • Park Jee-Yun
    • Journal of the Korean Geographical Society
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    • v.41 no.1 s.112
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    • pp.58-72
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    • 2006
  • The importance of R & D activities has been emphasized in modem economy due to rapid growth of high-tech industry. This research has taken a macroscopic approach to understand the spatial location pattern of company-affiliated R & D institute. According to the result based on this analysis, a number of company-affiliated R & D institutes have shown high centralization in Seoul Metropolitan Area(SMA); however, more serious analysis has shown that institutes have different regional tendencies based on their industrial classifications with lower high-tech tendencies show less centralization in the SMA. Moreover, it also has indicated that larger corporations or higher capability of hiring top class researcher have tendency to decentralize their institutes. The result also points out that institutes are likely to be located near their head offices or factories; or located along with other research institutes in the same industrial field. The locations of the institutes, however, have shown the regional differences as well. After taking all the characteristics into consideration, this study has categorized types of institutes locations into four groups.

Mapping Studies on Visual Search, Eye Movement, and Eye track by Bibliometric Analysis

  • Rhie, Ye Lim;Lim, Ji Hyoun;Yun, Myung Hwan
    • Journal of the Ergonomics Society of Korea
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    • v.34 no.5
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    • pp.377-399
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    • 2015
  • Objective: The aim of this study is to understand and identify the critical issues in vision research area using content analysis and network analysis. Background: Vision, the most influential factor in information processing, has been studied in a wide range of area. As studies on vision are dispersed across a broad area of research and the number of published researches is ever increasing, a bibliometric analysis towards literature would assist researchers in understanding and identifying critical issues in their research. Method: In this study, content and network analysis were applied on the meta-data of literatures collected using three search keywords: 'visual search', 'eye movement', and 'eye tracking'. Results: Content analysis focuses on extracting meaningful information from the text, deducting seven categories of research area; 'stimuli and task', 'condition', 'measures', 'participants', 'eye movement behavior', 'biological system', and 'cognitive process'. Network analysis extracts relational aspect of research areas, presenting characteristics of sub-groups identified by community detection algorithm. Conclusion: Using these methods, studies on vision were quantitatively analyzed and the results helped understand the overall relation between concepts and keywords. Application: The results of this study suggests that the use of content and network analysis helps identifying not only trends of specific research areas but also the relational aspects of each research issue while minimizing researchers' bias. Moreover, the investigated structural relationship would help identify the interrelated subjects from a macroscopic view.

The Effect of Herbal Medicine on Rheumatoid Arthritis Animal Model: A systematic Review of Animal Experiment Studies Published in Korea and Overseas (한약의 류마티스 관절염 동물 모델에 대한 치료효과: 국내 및 국외 논문에 대한 체계적 문헌 고찰)

  • Oh, Seung-Joon;Ha, Hyun Ju;Gu, Ji-Hyang;Park, Yang-Chun;Oh, Min-Seok;Jung, In-Chul;Lee, Eun-Jung
    • Journal of Korean Medicine Rehabilitation
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    • v.30 no.3
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    • pp.103-116
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    • 2020
  • Objectives This study was designed to review the effect of herbal medicine on animal model with rheumatoid arthritis. Methods We reviewed studies published both in Korea and overseas, all published after 2008. We investigated 8 databases, 6 Korean databases and 2 of abroad. Searching was conducted through flowchart and 24 studies met our guideline. Datas were extrated and organized as animal model characteristics, experimental period, study design, herbal medicine used as intervention and rheumatoid arthritis indicator. Results 336 articles were primarily selected. After screening, 24 articles were left in the end. All 24 studies showed that the herbal medicine used in the animal experiment was effective on treating rheumatoid arthris, proven by macroscopic, histological, hematological and osteological indicators. Conclusions The result showed that herbal medicine is effective in treating rheumatoid arthritis through various pathways. However, study design and intervention were all different from each other and we could not specify the certain compound, material or substance of efficacy. Further study should be conducted to figure out the effectiveness of herbal medicine on rheumatoid arthritis.

Analysis of Characteristics of the Dynamic Flow-Density Relation and its Application to Traffic Flow Models (동적 교통량-밀도 관계의 특성 분석과 교통류 모형으로의 응용)

  • Kim, Young-Ho;Lee, Si-Bok
    • Journal of Korean Society of Transportation
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    • v.22 no.3 s.74
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    • pp.179-201
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    • 2004
  • Online traffic flow modeling is attracting more attention due to intelligent transport systems and technologies. The flow-density relation plays an important role in traffic flow modeling and provides a basic way to illustrate traffic flow behavior under different traffic flow and traffic density conditions. Until now the research effort has focused mainly on the shape of the relation. The time series of the relation has not been identified clearly, even though the time series of the relation reflects the upstream/downstream traffic conditions and should be considered in the traffic flow modeling. In this paper the flow-density relation is analyzed dynamically and interpreted as a states diagram. The dynamic flow-density relation is quantified by applying fuzzy logic. The quantified dynamic flow-density relation builds the basis for online application of a macroscopic traffic flow model. The new approach to online modeling of traffic flow applying the dynamic flow-density relation alleviates parameter calibration problems stemming from the static flow-density relation.

Development and Application of Micromodel for Visualization of Supercritical CO2 Migration in Pore-scale (공극 규모에서의 초임계상 이산화탄소 거동 가시화를 위한 마이크로모델의 개발과 적용)

  • Park, Bogyeong;Lee, Minhee;Wang, Sookyun
    • Journal of Soil and Groundwater Environment
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    • v.20 no.4
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    • pp.73-82
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    • 2015
  • Despite significant effects on macroscopic migration and distribution of CO2 injected during geological sequestration, only limited information is available on wettability in microscopic scCO2-brine-mineral systems due to difficulties in pore-scale observation. In this study, a micromodel had been developed to improve our understanding of how scCO2 flooding and residual characteristics of porewater are affected by the wettability in scCO2-water-glass bead systems. The micromodel (a transparent pore structure made of glass beads and glass plates) in a pressurized chamber provided the opportunity to visualize scCO2 spreading and porewater displacement. CO2 flooding followed by fingering migration and dewatering followed by formation of residual water were observed through an imaging system. Measurement of contact angles of residual porewater in micromodels were conducted to estimate wettability in a scCO2-water-glass bead system. The measurement revealed that the brine-3M NaCl solution-is a wetting fluid and the surface of glass beads is water-wet. It is also found that the contact angle at equilibrium decreases as the pressure decreases, whereas it increases as the salinity increases. Such changes in wettability may significantly affect the patterns of scCO2 migration and porewater residence during the process of CO2 injection into a saline aquifer at high pressures.

Interface Structures of Ag-Si Contacts with Thermal Properties of Frits in Ag Pastes

  • Choi, Seung-Gon;Kim, Dong-Sun;Lee, Jung-Ki;Kim, Hyung-Sun
    • Korean Journal of Materials Research
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    • v.22 no.8
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    • pp.390-396
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    • 2012
  • Ag pastes added to Bi-oxide frits have been applied to the electrode material of Si solar cells. It has been reported that frits induce contacts between the Ag electrodes and the Si wafer after firing. During firing, the control of interfaces among Ag, the glass layer, and Si is one of the key factors for improving cell performance. Specifically, the thermo-physical properties of frits considerably influence Ag-Si contact. Therefore, the thermal properties of frits should be carefully controlled to enhance the efficiency of cells. In this study, the interface structures among Ag electrodes, glass layers, and recrystallites on an $n^+$ emitter were carefully analyzed with the thermal properties of lead-free frits. First, a cross-section of the area between the Ag electrodes and the Si wafer was studied in order to understand the interface structures in light of the thermal properties of the frits. The depth and area of the pits formed in the Si wafer were quantitatively calculated with the thermal properties of frits. The area of the glass layers between the Ag electrodes and Si, and the distribution of recrystallites on the $n^+$ emitter, were measured from a macroscopic point of view with the characteristics of the frits. Our studies suggest that the thermophysical properties should be controlled for the optimal performance of Si solar cells; our studies also show why cell performance deteriorated due to the high viscosity of frits in Ag pastes.