• Korean Journal of Materials Research
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• v.4 no.2
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• pp.194-205
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• 1994

In this research, we attempt to fabricate an excellent CFRC(Carbon Fiber Reinforced Carbon), which has good thermal and mechanical properties, with 8H/satin woven fabric prepreg, high modulus and high strength type continuous carbon fiber and raw coal tar pitch(RCTP) matrix or THF soluble fraction(THFSP) matrix which has good graphitizability. Green bodies were fabricated with hot press molding technique and CFRC samples were made after carbonization, impregnation, recarbonization and graphitization steps. For the purpose of characterization of the physical properties, SEM, polarized light microscope, TGA were observed, and tested flexural strength, modulus and ILSS. After heat treating the THFSP matrix up to $2300^{\circ}C$, the value of $C_0$/2 was 3.380$\AA$, which is analogous to the structure of natural graphite and the value of 2$\theta$ is $26.276^{\circ}$ approached to the Bragg's angle of natural graphite. As a result of TGA to test the high temperature air oxidation, the THFSP matrix, graphitized up to $2300^{\circ}C$, exhibited the best air oxidation resistance. And mechanical properties were increased up to 65~70% as fiber volume fraction increased. Because of the good orientation graphitizability, the fracture surface of THFSP matrix CFRC is very good.

• Composites Research
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• v.12 no.6
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• pp.74-82
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• 1999

The static and fatigue characteristics of polyurethane foam cored sandwich structures are investigated. Three types of the specimens with the glass fabric faces and the polyurethane foam core are used; non-stitched. stitched, and stiffened sandwich specimen. Especially additional structural reinforcements with the twisted polyester and glass fiber for thickness direction are made to stitched sandwich structure panel to minimize the delamination of structure which is stitched the upper and lower faces through the core and the resin is impregnated Into stitched fiber with the characteristics of low viscosity of resin at resin flow temperature and cured together with during the curing process. Bending strength of stitched specimen which is 50 mm $50{\times}50{\;}mm$ pitched is improved by 50 % as com-pared with non-stitched specimen and stiffened specimen is improved 10 times more than non-stitched structure. After fatigue testing of $10^6$cycles by 20% of ultimate load under monotonic load, the bending fatigue strength of non-stitched specimen is decreased by 27% of monotonic bending strength, 39% for stitched structure and 20% for stiffened specimen. To verify the aging effect of polyurethane form core, Ultrasonic C-scanning equipment is used to detect the damage of skin laminate alone after fatigue test. From results of UT C-scan images, there is no defect that can be damaged occurred during fatigue test. It is concluded that the decrease of bending strength for foam cored sandwich specimen is caused by the decrease of stiffness due to the aging of polyurethane foam core during fatigue cycles.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.2 no.4
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• pp.19-41
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• 2007

This research has a goal which is suggesting the way of constructing 'Cluster' which mean scheming the commencement of an enterprise in an early stage. Now it is reorganized into a IT industry structure 'Time-to market growth' is burst as a big issue. in that point, this research analyze the core success factor which is drawing from the existing IT industrial complex, and then it will be used to draw up to the 'Idealistic growth-support Cluster' on the basis of it, we pulled out various issues about the Corporate in the early stage of its growth. Therefore, this research is focused on presenting the ideal network(net) by considering the Network that organizations and business in Cluster or the network including the factors linked organizations and business in Cluster. therefore, this research carried out three big analysis. from the case investigation we pulled out the core growth factor, and then we approached the analysis of net structure for making application to Network Analysis. and then we analyzed that the characteristics of the Network after measuring by on the basis of analyzing core growth factor. and especailly, this research carried out the Core analysis for recognition of Core- support-frame by base Centrality Test on the net which is composed of growth support organizations at each Business. Judging from this, we can help to make full use of resources for the network analysis in Cluster and establish the Network Strategy by Structure comparison between the structure of industry-Cluster and ideal Business-support networks on the basis of the analysis from the Core-success-factor

• Journal of Conservation Science
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• v.32 no.2
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• pp.141-154
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• 2016

The gilt-bronze decorated bamboo mudguards with heavenly horse design excavated in 1973 at Cheonma Tomb of Shilla are the unprecedented relics in Korean history as it has its original structure. Although the bamboo mudguards were excavated in not only Cheonma Tomb, but also in Geumgwanchong and Geumryeongchong, all of them remains into pieces. In addition, there are no exact data related with its structure and manufacturing technique. The report deals with the manufacturing technique of the bamboo mudguards with heavenly horse design excavated in Cheonma Tomb through the naked eye's observation, X-Ray Fluorescence, and Transmission X-rays analysis etc. Bamboo mudguards basically have the three divided structure with central-focus structure of a radiation style. And the mudguards consists of Bratticing gilt-bronze, fabric, and bamboo plates together, as ornamental fringe of 4 plates. The surface of the gilt bronze plates was decorated with a variety of workmanship and pendant. Bamboo plates have a waved pattern by using about three hundred bamboo bark. Two types of textiles were mainly found in the textile plates, and the leather were partially found. In order to combine all plates together, gilt-bronze bottonhead, pendant decoration, and ornamental fringe were used. It would be helpful to study bamboo mudguards during 5th-6th centuries in Shilla period and basis investigations of Geumgwanchong and Geumryeongchong excavations.

• Journal of the Korean Geosynthetics Society
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• v.8 no.2
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• pp.47-54
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• 2009

The ballast track, the most common type of conventional railroad track in Korea, is deteriorated by abrasion of ballast, it's penetration into roadbed, and rugged surface of roadbed caused by cyclic loading of train. Persistent occurrence of those phenomena lead to insufficient drain capacity, one of major factors in track design, and it increases pore water pressure and decreases of shear strength under rainfall condition leading to unstable roadbed. In this study, cylindrical model tests are executed for 3 types of geotextile applying cyclic loading in order to observe the characteristics of displacement and bearing capacity of geotextile, and undrained condition has been applied for 0 day, 3 days and 7 days to each geotextiles. The results showed that there was about 1% difference at the final displacement rates between reinforced soils and nature soils and the displacement of the ground surface increases along with the degrees of the saturation. And in case that water contents exceeds the threshold, it is also apparent that weight and tensile strength of geotextile influences displacement of the ground surface. And the larger weight of geotextile is, the smaller plastic displacement. It is evaluated that non-woven fabric comes into effect on reducing the bearing capacity but, the weight of geotextile has little influence on it.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.4
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• pp.177-186
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• 2015

Until Mandelbrot introduced the concept of fractal geometry and fractal dimension in early 1970s, it has been generally considered that the geometry of nature should be too complex and irregular to describe analytically or mathematically. Here fractal dimension indicates a non-integer number such as 0.5, 1.5, or 2.5 instead of only integers used in the traditional Euclidean geometry, i.e., 0 for point, 1 for line, 2 for area, and 3 for volume. Since his pioneering work on fractal geometry, the geometry of nature has been found fractal. Mandelbrot introduced the concept of fractal geometry. For example, fractal geometry has been found in mountains, coastlines, clouds, lightning, earthquakes, turbulence, trees and plants. Even human organs are found to be fractal. This suggests that the fractal geometry should be the law for Nature rather than the exception. Fractal geometry has a hierarchical structure consisting of the elements having the same shape, but the different sizes from the largest to the smallest. Thus, fractal geometry can be characterized by the similarity and hierarchical structure. A process requires driving energy to proceed. Otherwise, the process would stop. A hierarchical structure is considered ideal to generate such driving force. This explains why natural process or phenomena such as lightning, thunderstorm, earth quakes, and turbulence has fractal geometry. It would not be surprising to find that even the human organs such as the brain, the lung, and the circulatory system have fractal geometry. Until now, a normal frequency distribution (or Gaussian frequency distribution) has been commonly used to describe frequencies of an object. However, a log-normal frequency distribution has been most frequently found in natural phenomena and chemical processes such as corrosion and coagulation. It can be mathematically shown that if an object has a log-normal frequency distribution, it has fractal geometry. In other words, these two go hand in hand. Lastly, applying fractal principles is discussed, focusing on pulp and paper industry. The principles should be applicable to characterizing surface roughness, particle size distributions, and formation. They should be also applicable to wet-end chemistry for ideal mixing, felt and fabric design for papermaking process, dewatering, drying, creping, and post-converting such as laminating, embossing, and printing.

• Journal of Conservation Science
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• v.36 no.1
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• pp.1-14
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• 2020

This study investigates the crystallinity distribution of ancient silk. Owing to the inherent multi-hierarchical structure of silk protein and the complicated structural changes that occur due to various burial environments, it is challenging but worthwhile to study ancient silk ageing behavior, which is based on the fact that ageing begins with a single fiber and then spreads to a whole fabric. Crystallinity was one of the most effective indicators found to reveal the ageing status of silk. Therefore, a synchrotron radiation-based X-ray diffraction(SR-XRD) method was employed to study the crystallinity distribution of single fibers of ancient silk unearthed from seven archaeological sites in China from historical periods including the warring states, Han dynasty, Song dynasty, and Ming dynasty. In comparison, the conventional X-ray diffraction method, which uses large amounts of samples, was also performed to determine the integral crystallinity of ancient silk. Thermal stability experiments by thermogravimetry(TG) as well as morphology observations by scanning electron microscopy(SEM) and optical microscopy(OM) all confirmed the deterioration of ancient silk. Moreover, the ageing mechanism of ancient silk was proposed with the assistance of an artificial ageing study. The results confirmed the effectiveness of SR-XRD as an ageing indicator, revealing the crystallinity distribution. This research could provide motivation to determine the deterioration status of ancient silk, and would also aid in explaining the fragility of ancient silk due to ageing.

• Korean Journal of Human Ecology
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• v.18 no.6
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• pp.1315-1321
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• 2009

The chemical composition of natural powder dye $Pinux^{TM}$ manufactured from Pinus radiata bark and dyeability of dyed silk fabrics with $Pinux^{TM}$ were examined. It is made up of the optimum dyeing condition of silk fabric according to the dyeing concentration, dyeing time, and dyeing temperature. Also, we examined the colorfastness and antibiosis of dyed silk fabrics to washing, rubbing, perspiration and light. For the analysis of the chemical composition of $Pinux^{TM}$, the total contents of phenolic compound, proanthocyanidin(PA) and anti-oxidative activities of the dye were analyzed. As a result, it was found that the main components of the $Pinux^{TM}$ manufactured from Pinus radiata bark is proanthocyanidin, mostly a flavonoid containing a procyanidin structure, and it consists of approximately 63% phenol. As a result of examining the dyeability of silk fabrics with $Pinux^{TM}$, it showed that the dyeability was best under the conditions of the concentration of dye $1{\sim}1.5%$(wt/v%), dyeing time of 90 minutes, and dyeing temperature at $90^{\circ}C$. It was found that the colorfastness of dyed silk fabrics, colorfastness to washing, perspiration for acidic and rubbing were as good as grade 4 or 4-5. However, the colorfastness to light was low at grade 1, the same as the results of other natural dyed fabrics. As a result of the antibiosis measurement for the $Pinux^{TM}$-dyed silk fabrics, it showed high antibacterial properties to Staphylococcus sureus at 99.6%.

• Journal of Fashion Business
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• v.5 no.1
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• pp.117-130
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• 2001

The purpose of this research focuses mainly on the establishment of: the image of the police that can be adopted to meet the demands of reality through the development of the design of policewomen's uniform in the times that require reestablishment of the image of the police; the image of the police that is appropriate for the organic structure of the society; and the image of the police that cooperate with the citizens. For background research I have considered the police and their uniforms from a theoretical point of view and have examined the process by which Korean policewomen's uniforms have changed. Actual research was carried out policewomen of Seoul Regional Police Station, was conducted and the results were utilized to figure out what the problem was. This research suggests an improvement measure by making four suits of summer and spring-and-autumn work-uniforms, and six suits of spring-andautumn and winter full-dress uniform. First the colors of work-uniforms and full-dress uniforms are not blue, which incites a feeling of coldness and stiffness, but are colors that are feminine and emit warmth---red, ivory, khaki, black, and beige. second pure, natural fiber is difficult to wash and is not an appropriate material for policewomen's uniforms when considering its cost and etc., fabrics that are a mix of synthetic fiber and natural fiber were chosen. Because mixed fabrics are cheaper and their ability to maintain shape is superior to that of natural fiber, mixed fabric is an appropriate material for policewomen's uniforms. third the feminine image of policewomen was considered; therefore, masculine image, which is rigid and strong, was avoided and the image was expressed in a serene and beautiful way. Also slim line was added to the current uniforms to emphasize feminine beauty. The conclusion of this study is that police officers in the 21st century want to be seen as the citizens cane and benevolent volunteers that live together with the citizens, not as suppressive and powerful people.

• Journal of Fashion Business
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• v.17 no.1
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• pp.131-144
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• 2013

The purpose of this study was to analyse the structure and contents of clothing construction field in the middle-school textbook of technology and home economics with curriculum revised in 2007. 10 kinds of textbooks certified by Ministry of Education, Science and Technology in 2010 were selected and home economics field in them was the subject of this study with the external characteristics such as textbook system, instruction area and contents included. This study was content analysis-oriented and descriptive with data calculated by frequency and percentage. The findings are as follows. In 'Reality of Home-Life', food life area showed highest as 34.4% followed by clothing life(28.7%) and dwelling life(28.7%). The portion of present teachers in writing staffs was highest while there was no textbook where professors of each field were included in writing staffs. The contents of costume society, clothes material, clothes management from section 'Choice and Management of Clothes' in the chapter 'Family Life' and clothing construction from the section 'Making and Modifying Clothes' of the chapter 'Reality of Home-Life' were analysed in this study. Clothing construction-related fields were suggested separately by method of measurement, construction theory, drafting theory, drafting an original form, fabric trimming, utilization of the original form, length measure, cloth cutting, hand stitching, how to use a sewing machine, basting and correction, needlework process, completion, and evaluation. The contents of the unit 'Making Shorts' were about clothing construction theory, human body measurement, drafting an original form, process of making shorts and activity/research/experience. The contents of the unit 'Wearing Clothes after Fixing' in clothing construction-related field were about how to fix and recycling.