1,721,016 research outputs found
Jeon, Se hoon
No full text학위논문(석사)----아주대학교 일반대학원 :에너지시스템학부,2008. 2반도체 제조공정을 통해 제작되는 미세유체역학 디바이스는 생명-의학 분야에 진단용으로 광범위하게 사용되고 있다. 항산화단백질인 SOD1 단백질의 변이와 응집은 신경퇴행성 질환의 하나인 가족성 근위축측삭경화증(ALS)의 병인으로 추정되고 있다. SOD1 단백질의 변이와 응집현상을 실시간으로 관찰하기 위하여 굴절률의 변화를 측정하여 생체물질의 상호작용을 인지할 수 있는 표면 플라즈몬 공명분석방법이 수행되었다. 표면 플라즈몬 공명분석에서 사용하는 금 박막이 증착된 유리 기판에 여러 종류의 단백질을 부착시켜, 여러 종류의 실험을 동시에 실행할 수 있도록 미세유체역학에 기반을 둔 디바이스를 제작하였다.
미세유체역학 디바이스는 상용 반도체공정을 이용한 복제주조방법을 이용하여 폴리디메틸실록산(PDMS)으로 제작되었다. 포토리소그래피 공정을 통하여 상용 CAD S/W로 작성한 형상으로, SU-8이 증착된 실리콘 웨이퍼가 몰드로 사용되었고, 여기에 PDMS를 부어 경화시키는 방법으로 미세유체역학 디바이스를 제작하였다. 이 디바이스를 작동시키는 구동력은 모세관력으로, 유속계와 펌프 등과 같은 추가적인 실험장치들이 불필요하다는 특징을 가지고 있다. 이 연구를 통하여 축적한 일련의 디바이스 설계 및 제작기법을 이용하여, 향후 PDMS의 표면에 나노분말소재 등의 기능기를 부착하여 SOD1 단백질의 변이와 응집현상을 진단할 수 있는 키트로의 응용도 가능하다.Chapter 1 Introduction = 1
1.1 Amyotrophic Lateral Sclerosis = 1
1.2 Immunoassay & Surface Plasmon Resonance = 3
1.3 Microfluidic Devices = 6
1.4 Research Goal = 8
Chapter 2 Fabrication of Microfluidic Devices = 10
2.1 Materials = 10
2.2 Polydimethylsilosane = 12
2.3 Fabrication Processes = 14
2.4 Design of Microfluidic Devices = 16
2.5 Fabrication of Microfluidic Devices = 21
Chapter 3 Results and Discussions = 25
3.1 Test of Microfluidic Devices = 25
3.2 SPR Experiments = 30
Chapter 4 Conclusion = 32
References = 33
Abst ract in Korean = 39MasterMiniaturized devices, based on a combination of microfabrication technology and life science, are widely used in medical fields. Mutation and aggregation of superoxide dismutase 1 (SOD1) are expected as one of the causes of familial amyotrophic lateral sclerosis (ALS). To investigate the surface phenomena of SOD1 using surface plasmon resonance (SPR) spectroscopy, microfluidic devices are fabricated with polydimethylsiloxane (PDMS) to construct immobilized protein arrays.
Microfluidic devices are designed and fabricated by replica molding method with commercial semiconductor fabrication processes. To make film masks for the SU-8-photoresist-based photolithographic process, two-dimensional drawing is done with commercial computer-aided design software. After pouring PDMS onto the molds (silicon wafers patterned with SU-8) and curing, surface of cured PDMS is modified from hydrophobic to hydrophilic by simple chemical method for the bio-compatibility. With these fabricated devices, microfluidic flow experiments are done to make multiple protein-patterned sensor surface of SPR glass substrates. In these experiments, flow control equipments are unnecessary because they use only capillary force as the driving force of fluid flow
신호를 처리하는 방법, 시스템 및 비일시성의 컴퓨터 판독 가능 기록 매체
No full textAccording to one aspect of the invention, there is provided a signal processing method, wherein a frame is generated in which at least one position of occurrence of a transition in a pulse value is determined from an input bitstream. According to another aspect of the invention, there is provided a signal processing method, wherein a frame including at least one pulse having a pulse width not less than a minimum pulse width is generated from an input bitstrea
Development of new device for measuring thermal stresses
No full textIn recent years, numerous analytical and experimental researches have been performed on the prediction of thermal stresses in mass concrete structures. However, due to the difficulty of the problem, limitations still exist for both analytical and experimental methods of measuring thermal stresses in mass concrete. In this research, a new experimental device measuring thermal stresses directly in a laboratory setting is developed. The equipment is located in a temperature chamber that follows the temperature history, which has been previously obtained from temperature distribution analyses. Thermal forces are measured continuously by two load cells in the device. The results show that the thermal stresses estimated by the newly developed device agree well with general stress variations in actual structures. (C) 2002 Published by Elsevier Science Ltd
Cohesive fracturing and stresses caused by hydration heat in massive concrete wall
No full textAvoidance of cracking damage due to hydration is an important objective in the design of nuclear reactor containments. Assessment of the safety against cracking requires a realistic material model and its effective numerical implementation. Toward this goal, the paper develops a comprehensive material model which includes approximate simulation of cracking based on the principles of cohesive fracture mechanics, as well as an up-to-date creep formulation with aging and temperature effects. A standard heat conduction model is incorporated in the analysis as well. Since the crack width is the most important characteristic of cracking damage, particular attention is paid to crack spacing which governs crack width. The results of stability analysis of parallel crack systems based on fracture mechanics are used to estimate the spacing of open cracks as a function of their depth. Numerical simulations clarifying various aspects of hydration heat effects are presented
An experimental study on thermal conductivity of concrete
No full textInfluencing factors on thermal conductivity of concrete are quantitatively investigated by QTM-D3-that is, a conductivity tester developed in Japan-and a prediction equation of thermal conductivity of concrete is suggested from the regression analysis of test results. To consider the interacted factors influencing thermal conductivity of concrete, mortar, and cement paste, seven testing variables such as age, water-cement (W/C) ratio, types of admixtures, aggregate volume fraction, fine aggregate faction, temperature, and humidity condition of specimen were adopted in this test. According to experimental results, aggregate volume fraction and moisture condition of specimen are revealed as mainly affecting factors on the conductivity of concrete. Meanwhile, the conductivities of mortar and cement paste are strongly affected by the W/C ratio and types of admixtures. However, age hardly changes the conductivity except for very early age. Finally, the conductivity of concrete is represented in terms of the aggregate volume fraction, fine aggregate fraction, W/C ratio, temperature, and humidity condition of specimen. (C) 2002 Elsevier Science Ltd. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Full text linkWe 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
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