• Title/Summary/Keyword: 분산 방법

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Preparation of Gold-Peptide Hybrid Nanoparticles and Its Applications in Catalytic Reduction of Methylene Blue (금-펩타이드 하이브리드 나노입자의 제조와 메틸렌 블루의 촉매 환원 응용)

  • Hur, Yun-Mi;Min, Kyoung-Ik
    • Applied Chemistry for Engineering
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    • v.32 no.2
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    • pp.163-167
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    • 2021
  • In the present work, we studied a method for the synthesis of uniform gold-peptide hierarchical superstructures using tyrosine rich peptide, Tyr-Tyr-Leu-Tyr-Tyr (YYLYY). Peptide nanoparticles self-assembled by dityrosine bonds were synthesized through the photo-crosslinking reaction of the peptide, and gold-peptide hybrid nanoparticles were synthesized using biomineralization properties of tyrosine in a green synthetic manner. The synthesized gold-peptide hybrid nanoparticles were then characterized by transmission electron microscopy, scanning electron microscopy, dynamic light scattering, UV-vis spectroscopy, scanning transmission electron microscopy-energy dispersive X-ray spectroscopy, and X-ray diffraction. Furthermore, the catalytic activity of gold-peptide hybrid nanoparticles was confirmed by the reduction reaction of methylene blue where the catalytic reaction rate constant was 13.4 × 10-3 s-1.

A Natural Field Experiment on Citizens' Giving Behavior: Analysis on Red Kettle Campaign of Salvation Army (기부참여행동에 대한 현장실험 연구(Natural Field Experiment) : 구세군 자선냄비 모금을 활용한 분석)

  • Kang, Chulhee;Park, Sohyun
    • Korean Journal of Social Welfare Studies
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    • v.47 no.3
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    • pp.61-84
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    • 2016
  • Competing theories predict that others' contributions might be either substitutes or complements to one's own. Based on such competing theoretical discussions, this study attempted to examine the relationship between information about other citizens' giving behavior and citizens' giving. To achieve study objective, this study utilized a natural field experiment that investigates citizens' voluntary contributions to three types of kettle (transparent kettle with no money, transparent kettle with a large amount of bills and coinage, and red invisible kettle) during Salvation Army Red Kettle Campaign in 2011 and 2012. The experiment took place at subway stations which does not differences in the amount donated in previous years. In this field experiment, this study manipulated information about other citizens' giving behavior available to citizens by altering the different red kettle donation boxes. This study found that there are no positive or negative information effect on individual citizens' contributions. The results did not show either crowding-out effect or crowing-in effect. Thus, this study showed that social information has statistically non-significant impact on the propensity to donate and the amount donated.

Development of Saengshik Beverage Products and Their Physico-chemical Properties (생식 음료 개발 및 이화학적 특성)

  • Lee, Ju-Yeon;Mok, Chulkyoon
    • Food Engineering Progress
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    • v.13 no.4
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    • pp.341-347
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    • 2009
  • Saengshik beverage products were developed to improve the convenience in consumption, and thereby to expand the Saengshik market. Beverages were prepared from 3 commercial Saengshik products (ES, BS, SS) by mixing with water using a high shear blender. The physicochemical and sensory properties of the Saengshik beverage product were compared. The most acceptable beverage product was made of BS at 7.7% (w/w) level. The apparent viscosity of the beverages increased as the Saengshik levels increased. The beverages at lower Saengshik levels showed dilatant fluid characteristics, while they were Newtonian and pseudoplastic fluids at middle and high Saengshik levels, respectively. The beverage products also showed rheopectic type time-dependency at middle (5.7-9.7%) Saengshik levels, while they were time independent at low and high levels.

A Record and Conservation of Cultural Heritages through Web Ecomuseum : the Case of Mountain Mudeung (웹 생태박물관을 활용한 문화유산의 기록과 보존 : 무등산을 중심으로)

  • Noh, Shi-Hun
    • The Korean Journal of Archival Studies
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    • no.27
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    • pp.209-238
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    • 2011
  • Ecomuseum which appeared in France in 1968 and widely diffused over the world, is a new type of museum. The purpose of this museum is not to simply possess and exhibit the existing relics, but to discover the locational senses of a territory by in-situ conserving and interpreting its entire natural and cultural heritages, and to plan the participation of its population and the development of its local community. The significance of this museum can be found in the recovery of disappearing collective memories of a territory, the restoration of the cultural identity of its population and the revitalization of a underdeveloped area. As the majority of these museums are fragmented or open air museums, an 'web ecomuseum' which makes the remote offering of informations about whole dispersed heritages and their holistic interpretation possible by digitalizing, recording, conserving, interpreting and utilizing related heritages, is necessary. This paper considers the possibility of web ecomuseum and its constitution contents and methods through the case of Mountain Mudeung area. Especially, in relation to the latter, this paper suggests a plan which consists of selection of own local themes, construction of digital archives, design of web expositions and production of electronic cultural maps.

A study on the construction of records management criteria (기록관리기준 조사 및 작성에 관한 연구)

  • Lee, Mi-young
    • The Korean Journal of Archival Studies
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    • no.15
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    • pp.185-218
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    • 2007
  • With the reform of records management law, the organization should manage a new criteria scheme of record management based on business task and process. The new criteria scheme includes business explanation, preservation period, cause of setting up preservation period and opening information, access authority, keeping records or not. In the past, there were also some regulations and criteria but, records management criteria should be managed systematically and rationally than past in electronic environment. In this study, some previous cases about records management criteria constructing and operating were introduced first. And various characters about records management criteria were reviewed after that, process sample and methodology were proposed for construction of each criteria. If the records management criteria were constructed properly according to goals and objectives of records management and the results were managed through electronic system, the consistency of records management will be kept well and value changes of business and records will be reflected dynamically.

A study on the test workpiece for accuracy analysis of multi-axis turning and milling center (선반 및 밀링 겸용 다축 복합가공기의 정밀도 검증을 위한 표준공작물에 대한 연구)

  • Shin, Jae-Hun;Kim, Hong-Seok;Youn, Jae-Woong
    • Journal of the Korea Convergence Society
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    • v.9 no.11
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    • pp.277-284
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    • 2018
  • Recently, the demand for precision machining through multi-axis machining has been greatly increased. However, it is difficult to evaluate the geometrical accuracy of the machine tool because of its complicated geometric relationship. In this study, we organized the KS/ISO specifications which are distributed in various regulations, and re-organized the geometrical precision evaluation items of multi-axis machine tools. In addition, a test workpiece was proposed to evaluate and analyze the accuracy of a multi-axis machine tool, and a test workpiece was machined according to predetermined methods and procedures, and then the machined surfaces were measured using CMM. As a result, it was verified that the machining results of the standard workpiece and the precision of the machine tool were very similar qualitatively and quantitatively. From these results, it can be confirmed that the precision analysis of the multi-axis machine tool is possible only by machining the test workpiece.

Spatiotemporal Movement Density and Stopping Characteristics of Urban Walking Tourists by Season - Focused on Tourists of Bukchon Hanok Village in the Spring and Summer - (도심 도보관광자의 계절별 시·공간 이동밀도 및 멈춤 특성 - 북촌한옥마을의 봄·여름 관광자들을 대상으로 -)

  • Yun, Hee Jeong;Kang, Dong Jin;Shin, Sang Hyun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.47 no.4
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    • pp.1-11
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    • 2019
  • The purpose of this study is to determine urban walking tourists' spatiotemporal movement densities and the stopping characteristics by season. With the Bukchon Hanok Village in Seoul, as the study site, a GPS-based smartphone application collected spatiotemporal data, and GIS and statistical methods were used to analyze the urban walking tourists' spatiotemporal activities in the spring and summer. The results show that the moving and staying variables of urban walking tourists differ significantly by season. In addition, spatiotemporal movement densities and stopping characteristics using ArcGIS's tools show clear spatial and temporal concentrations along the main access roads and commercial areas of the study site in the spring and summer. Policy-makers and developers of urban walking tours should use these spatiotemporal concentrations of walking tourists to define policies that would control the capacities of urban walking areas and distribute tourists spatially and temporally.

The effects of Academic Self-efficacy and Resilience on Perception of Professionalism with Pre-service Early Childhood Teachers (예비유아교사의 학업적 자기효능감과 회복 탄력성이 교직 전문성 인식에 미치는 영향)

  • Bae, Jae-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.3
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    • pp.149-156
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    • 2019
  • This study investigated the effects of academic self-efficacy and resilience on perception of professionalism. The survey questionnaire was completed by 313 pre-service early childhood teachers. SPSS Win program was used to perform MANOVA and Multiple Regression Analysis. (1)The self-regulatory efficacy was significantly different according to grade and experience of child care practice. (2)The control and sociality, positivity were significantly different according to grade and experience of child care practice. (3)The perception of professionalism was significantly different according to grade and experience of child care practice. (4)The self-regulatory efficacy and the difficulty preference affected perception of professionalism. (5)The positivity and control affected perception of professionalism. This study indicated that it is necessary to make efforts for increasing perception of professionalism in pre-service early childhood teachers.

A Numerical Study on the Reduction Effect of Blasting Vibration with Cut Method (심발공법에 따른 발파진동 저감효과에 대한 수치해석적 연구)

  • Son, Ji-Ho;Kim, Byung-Ryeol;Lee, Seung-Joong;Kim, Nam-Soo;Lee, Hyo;Choi, Sung-Oong
    • Explosives and Blasting
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    • v.37 no.1
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    • pp.1-13
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    • 2019
  • The repeated blasting vibration, which is induced commonly in NATM excavation site, can cause a severe damage to the nearby facilities. It is known that the most effective method for reducing blasting vibration includes the use of electronic detonator, deck charge and change of cut method, and so forth. In order to analyze the effect of blasting vibration reduction, in this study, three-dimensional FDM (Finite Difference Method) program FLAC3D has been used for reflecting the blasting hole, delayed time and charging amount. Also the numerical analysis has been performed by applying a dynamic load to each blasting hole. The cut method has been applied with several methods, such as V-cut and Double-drilled parallel cut, which are common in tunnel construction sites. Also, the field test blasting has been carried out in order to compare the measured data with results of numerical analysis. It was shown that the numerical analysis and the field measurement coincide well.

Preparation of Monodisperse PEGDA Microparticles Using a Dispensing Needle Based Microfluidic Device (주사기 바늘 기반의 미세유체 장치를 이용한 단분산성 PEGDA 입자의 제조)

  • Jin, Si Hyung;Kim, Taewan;Oh, Dongseok;Kang, Kyoung-Ku;Lee, Chang-Soo
    • Korean Chemical Engineering Research
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    • v.57 no.1
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    • pp.58-64
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    • 2019
  • This study presents a novel method for preparing monodisperse polyethylene glycol diacrylate (PEGDA) microparticles in a dispensing needle based microfluidic device. The microfluidic devices are manufactured by manually assembling various off-the-shelf products without using additional equipment. In this microfluidic device, the volumetric flow rates of the dispersed phase of PEGDA solution and the continuous phase of oil are controlled to generate monodisperse PEGDA droplets. The PEGDA droplet contains photo-initiator thus it is crosslinked to microparticle by photopolymerization at the ends of the device. The particle size is easily controlled by adjusting the volume flow rate and the size of the microfluidic device. The monodispersity of the particles is calculated by a coefficient of variation of 2.57%. To demonstrate the biological applications of PEGDA particles, cells are encapsulated and observed for proliferation and viability.