1,721,214 research outputs found
Kim Yoon Hwan
No full text학위논문(석사)--아주대학교 일반대학원 :응용생명공학과정,2010. 2감사의 글
Abstract
List of Figure
List of Table
Ⅰ. Introduction
Ⅱ. Theoretical Approach
A. Dextran
B. Pectin
C. Hyaluronic acid
D. Chitosan
E. Example regarding prevention of protein adsorption
F. Electrospinning
G. BCA(Bicinchoninic acid) assay
Ⅲ. Material and methods
A. Material
B. Attachment of polysaccharide on film
C. Adsorption of protein on surface
D. Analysis
E. Preparation of PVA membrane
F. Measurement of concentration amounts and adsorption amounts
Ⅳ. Results and discussions
A. Fluorescence Intensity for BSA quantitative analysis
B. Data analysis using Isoelectric point
C. Data analysis using structure of hydrogel
D. Hystogram regarding protein adsorption distribution
E. Preparation of PVA membrane
F. Polysaccharide coating on membrane surface
G. Relation between the concentration of solution and layer thickness
H. Measurement of water flow rate
I. Measurement of concentration amount and adsorption amount
J. Preparation of polysaccharide layer introduced hydrophilic branch
1 Carboxyl-terminated PEG synthesis
2 Surface modification of complex polysaccharide layer
3. Estimation of adsorption ability for modified polysaccharide layer
Ⅴ. Conclusion
Reference
국문요약MasterThis study makes to reduce a protein adsorption to the surface and obtain a high-yield product while we carry out the separation and extraction of protein. Adsorption of Protein, the most representative material among biomolecules, occurs at surface of membrane and disturbs efficient separation and extraction. To prevent the adsorption of protein, surface of membrane was modified into hydrophilic surface. In order to obtain hydrophilic surface, we used hydrophilic polysaccharide such as Pectin, Dextran, Hyaluronic acid and chitosan which is known a effective biomolecule's adsorption preventer. In order to enhance transmittance, we make membrane having a porous structure by using electrospinning. The modified surface of membrane was observed by SEM(Scanning Electron Microscope) and AFM(Atomic Force Microscope) and concentration amounts and adsorption amounts of protein were measured by BCA(Bicinchoninic acid) assay. And ultrafiltration system was used to investigate water flow rate. And the hydrophilic group is introduced into polysaccharide layer. Through this study, the protein adsorption of surface coated by polysaccharide was affected by electrostatic property between protein and polysaccharide. And the higher hydrophilicity of surface coated by polysaccharide is, the lower adsorption ratio of protein is. Also the membrane introducing MPEG-COOH on chitosan layer have an excellent performance regarding prevention of protein adsorption. These results lead us to the conclusion that membrane of several types were prepared by introducing functional group
Optimal UAV formation guidance laws with timing constraint
No full textIn this paper, optimal guidance laws for multiple vehicles formation flight are addressed. The proposed laws are obtained as state-feedback solutions of linear quadratic optimal control problems to minimize the time varying energy cost with terminal constraints on position and velocity. Since the proposed laws are able to control the flight time, they are possible to make all vehicles join the formation concurrently at a specified time. A method to compensate the acceleration or maneuver of the formation leader is included in the guidance laws. And an inter-vehicle collision avoidance scheme is also considered. The performance of the guidance laws is tested via various numerical simulations
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Realization of Both High-Performance and Enhanced Durability of Fuel Cells: Pt-Exoskeleton Structure Electrocatalysts
No full textCore-shell structure nanoparticles have been the subject of many studies over the past few years and continue to be studied as electrocatalysts for fuel cells. Therefore, many excellent core-shell catalysts have been fabricated, but few studies have reported the real application of these catalysts in a practical device actual application. In this paper, we demonstrate the use of platinum (Pt)-exoskeleton structure nanoparticles as cathode catalysts with high stability and remarkable Pt mass activity and report the outstanding performance of these materials when used in membrane-electrode assemblies (MEAs) within a polymer electrolyte membrane fuel cell. The stability and degradation characteristics of these materials were also investigated in single cells in an accelerated degradation test using load cycling, which is similar to the drive cycle of a polymer electrolyte membrane fuel cell used in vehicles. The MEAs with Pt-exoskeleton structure catalysts showed enhanced performance throughout the single cell test and exhibited improved degradation ability that differed from that of a commercial Pt/C catalyst. (Figure Presented). © 2015 American Chemical Society1441sciescopu
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
PtPdCo ternary electrocatalyst for methanol tolerant oxygen reduction reaction in direct methanol fuel cell
No full textCarbon-supported PtPdCo/C ternary electrocatalysts were prepared by using the sodium borohydride method for use as a cathode catalyst in direct methanol fuel cells (DMFCs). The electrocatalyst particles with a size of 2-3. nm were uniformly dispersed on carbon supports. PtPdCo/C showed a similar performance compared to commercial Pt/C in the oxygen reduction reaction (ORR) tests conducted with a rotating disk electrode (RDE). On the other hand, PtPdCo/C showed higher methanol tolerance than Pt/C in acidic media with methanol. In the single-cell tests, the performance of the PtPdCo/C electrocatalyst was approximately 50% higher than that of Pt/C owing to its enhanced methanol tolerance. In the long-term operation test with the single-cell, the maximum power density of PtPdCo/C decreased only by 14% from its initial value. These results indicate that the PtPdCo/C catalyst is potentially an alternative electrocatalyst for the cathode in DMFCs. © 2014 Elsevier B.V.All rights reserved.131341sciescopu
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