고무강화 폴리스티렌과 유기화된 층상 실리케이트 나노복합재료의 합성 및 물성

이성재 수원대학교 산업기술연구소 2002 산업기술연구소논문집 Vol.17 No.-

Polymer/clay nanocomposites are potential materials with attractive properties such as improved stiffness, dimensional stability, barrier resistance, thermal stability and flame retardency. Many researches have focused on the property improvement of thermoplastics such as polystyrene with organically modified layered silicates, but open literatures have not been yet found on the rubber-toughened polystyrene by the author's knowledge. High impact polystyrene (HIPS) is known as the rubber-toughened polystyrene to improve the impact strength and toughness of glassy polystyrene. Current research issues of HIPS include high performance HIPS such as glossy, transparent, chemical-resistant, high strength and flame-retardant grades. Naturally, the introduction of clay would be one of good candidates to achieve these purposes. In this study, the preparation of HIPS/organically modified layered silicate nanocomposites by in situ polymerization is presented and the characterization techniques of the material are also discussed. Major attention will be focused on the dispersion of silicate layer and the change in rubber particle size affected by the clay loading.

1차 대전과 프랑스의 복지 정책

이성재 충북대학교 인문학연구소 2013 人文學誌 Vol.46·47 No.-

What impact did the First World War make on the history of the French social welfare system? This question has not drawn much the attention in the previous studies on the French welfare system. The reason was that most of related studies have emphasized that the welfare-related measures already had existed before 1914 and they were only translated into a set of laws during 1928-1930. However, it was the First World War that became the momentum for the systematic development of welfare-related measures that had been cautiously introduced before. And France responded to the newly appearing social problems relying on those actively organised measures. Why did the First World War become the important turning point in the French social welfare system? The First World War made such a deep impact on the social structure, income distribution between labor and capital, administrative structure and social relations that it made a favorable condition for the establishment of full-fledged socal insurance system. In this course of changes, public assistance system was not considerably changed, the social insurance system based on individual`s saving and capital was transformed into the one centered on the protection for the waged workers. And Finally, "`Republican social model`` based on a strong local autonomy and individual savings had come to disappear in 1945.

극상근의 기능적 전기자극에서 자극 강도에 영향을 미치는 해부학적 요인

이성재,권범선,전동진,김병희,이지영 대한재활의학회 2004 Annals of Rehabilitation Medicine Vol.28 No.1

Objective: This study was designed to evaluate the contribution of anatomical factors to the stimulation intensity needed for functional electrical stimulation (FES) of shoulder girdle muscles, especially the supraspinatus. Method: Anatomical dimensions, including the length of the arm and scapular spine, were measured in twenty three normal subjects. Depth and thickness of the supraspinatus and trapezius muscle were measured ultrasonographically. FES was applied for supraspinatus muscles, and the minimal intensity required to induce contraction was recorded. Correlations of intensity with the anatomical dimensions were investigated statistically. Results: The thickness of the supraspinatus muscle and the length of the scapular spine showed statistically significant correlations with the minimal intensity for FES of supraspinatus muscles. No other anatomical measurements showed significant correlation. Conclusion: The intensity required for FES was affected by the thickness and length of muscles, rather than other anatomical variables. The results of this study suggest that one of the major factors contributing to the determination of the intensity of FES is the size of muscles. If the intensity could be estimated before stimulation, based on the size of muscle, unnecessary discomfort of the patients would be avoided.

하천의 유지용수량 산정방법에 관한 연구

이성재 한국수자원학회 1986 물과 미래(한국수자원학회지) Vol.19 No.2

통합의료, 의료인과 정부에 바란다

이성재 대한의사협회 2012 대한의사협회지 Vol.55 No.6

Our aging society, rapid growth of diseases resulting from unhealty habits, frequent occurrences of sickness, and variations in the awareness of health by patients, the worldwide need for integrative medicine, which means the incorporation and integration of complementary and alternative medicine (CAM) into conventional medical systems, is growing rapidly. The most widely available forms of CAM in the treatment of diseases in the U.S. and Europe are acupuncture,chiropractic, phytomedicine (western herbal medicine), mind-body therapies, and nutrition therapy. The well-known hospitals in the U.S. and in Europe (e.g., Harvard, Memorial Sloan-Kettering Cancer Center, Duke, Maryland, Essen, and Humboldt) are offering integrative medicine. The clinical practices as well as the education on CAM of medical schools is becoming more widespread in Korea. It is critical for us as physicians to be aware that the role of CAM is to support and complement conventional medicine, not to substitute for it. To manage chronic diseases effectively, it is imperative for physicians to incorporate and integrate Korean oriental medicine as well as CAM into the conventional medical systems. It is the duty of the medical universities and hospitals to integrate care delivery proven by CAM therapies into the conventional medicine and to develop the standard curriculum for integrative medicine at the undergraduate and graduate levels. To globalize Korean oriental medicine and to scientifically prove the efficiency of CAM, the role of integrative medicine is critical. One of the most important roles of the Ministry of Health and Welfare is to support the hospitals in which integrative medicine is systematically practiced and financially supported. In order to successfully accomplish integrative medicine in Korea, it is important to not only establish an integrative medicine center, but to also develop the contents and clinical pathway along with legal systems regarding integrative medicine with the support of the specialists in the field of integrative medicine.

BIM 기반 디자인 프로세스에서의 파라메트릭 디자인 툴 활용에 관한 연구

이성재,홍규선,강호원 한국문화공간건축학회 2016 한국문화공간건축학회논문집 Vol.- No.53

The theoretical framework of this study focuses on design aspects of BIM as a parametric design tool to study and generate complex geometric forms based on series of parameters and pre-programmed rules, and to test a variety of simulated design alternatives responding to dynamic variety of geometrical, functional and environmental constraints in the process of design. BIM is one of the most prominent themes in today’s architectural industry, and has many benefits that can be directly applied to design studies during the early design phase. However in Korea, BIM is still limitedly recognized as a documentation tool to produce design deliverables or only as an integrated platform to closely collaborate with other engineering and construction disciplines. Therefore, this study explores theoretical basis of parametric design related to BIM, and also intends to analyze how parametric thinking and methodologies can be applied to design process in architectural practice through international case studies and how they are evolving into the next phase.

Influence of preparation parameters on rheological behavior and microstructure of aqueous mixtures of hyaluronic acid/poly(vinyl alcohol)

이성재,홍정숙,이승종,안경현,Hyun-Ok Park 한국유변학회 2005 Korea-Australia rheology journal Vol.17 No.2

Aqueous mixtures of hyaluronic acid and poly(vinyl alcohol) system and hydrogels thereof were introduced to obtain new bioartificial materials that have excellent mechanical properties, biocompatibility and enhanced rheological properties. The interactions between hyaluronic acid and poly(vinyl alcohol) and/or borax were investigated by rheological measurements. Preparation parameters of the aqueous mixtures were mixture composition, the degree of hydrolysis of poly(vinyl alcohol) and borax concentration. From the rheological behavior, it could be deduced that the key factor of the interaction between hyaluronic acid and poly(vinyl alcohol) was the hydrogen bonding between them and the effect was pronounced with borax. Enhanced viscosity was observed at the composition of 20 wt% of hyaluronic acid solution and 80 wt% of poly(vinyl alcohol) and borax solution. Rheological properties were influenced by the degree of hydrolysis of poly(vinyl alcohol) and borax concentration. As the degree of hydrolysis and borax concentration increased, rheological properties increased due to the increased hydrogen bonding and networking of hyaluronate aggregates. Physical hydrogels from hyaluronic acid and poly(vinyl alcohol) were prepared and the composition dependence of the gels was rheologically investigated as well.

Flow behavior of high internal phase emulsions and preparation to microcellular foam

이성재 한국유변학회 2004 Korea-Australia rheology journal Vol.16 No.3

Open microcellular foams having small-sized cell and good mechanical properties are desirable for many practical applications. As an effort to reduce the cell size, the microcellular foams combining viscosity improvers into the conventional formulation of styrene and water system were prepared via high internal phase emulsion polymerization. Since the material properties of foam are closely related to the solution properties of emulsion state before polymerization, the flow behavior of emulsions was investigated using a controlled stress rheometer. The yield stress and the storage modulus increased as viscosity improver concentration and agitation speed increased, due to the reduced cell size reflecting both a competition between the continuous phase viscosity and the viscosity ratio and an increase of shear force. Appreciable tendency was found between the rheological data of emulsions and the cell sizes of polymerized foams. Cell size reduction with the concentration of viscosity improver could be explained by the relation between capillary number and viscosity ratio. A correlative study for the cell size reduction with agitation speed was also attempted and the result was in a good accordance with the hydrodynamic theory.

Emulsion rheology and properties of polymerized high internal phase emulsions

이성재 한국유변학회 2006 Korea-Australia rheology journal Vol.18 No.4

High internal phase emulsions are highly concentrated emulsion systems consisting of a large volume of dispersed phase above 0.74. The rheological properties of high internal phase water-in-oil emulsions were measured conducting steady shear, oscillatory shear and creep/recovery experiments. It was found that the yield stress is inversely proportional to the drop size with the exponent of values between 1 and 2. Since the oil phase contains monomeric species, microcellular foams can easily be prepared from high internal phase emulsions. In this study, the microcellular foams combining a couple of thickeners into the conventional formulation of styrene and water system were investigated to understand the effect of viscosity ratio on cell size. Cell size variation on thickener concentration could be explained by a dimensional analysis between the capillary number and the viscosity ratio. Compression properties of foam are important end use properties in many practical applications. Crush strength and Young's modulus of microcellular foams polymerized from high internal phase emulsions were measured and compared from compression tests. Of the foams tested in this study, the foam prepared from the organoclay having reactive group as an oil phase thickener showed outstanding compression properties.

등속성 편심성 우력 측정을 이용한 경직의 정량적 평가

이성재,권범선,박승태 大韓再活醫學會 1999 Annals of Rehabilitation Medicine Vol.23 No.4