• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.733-736
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• 2000

In the first step of the LIGA process a resist layer, typically PMMA(polymethylmethacrylate), is pattered by deep X-ray lithography. Then the exposed parts are dissolved by an organic developer. To describe the developer. To describe the development course the parameters influencing the development process was investigated. The developed depth is proportional to the square root of the development time which suggests that the development rate increases with increasing dose value and temperature. So the development course can be described by a phenomenological equation.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.108-113
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• 2016

A miniaturized lab-scale Cu plating cell for the metallization of electronic devices was fabricated and its deposit uniformity and profile were investigated. The plating cell was composed of a polypropylene bath, an electrolyte ejection nozzle which is connected to a circulation pump. In deposit uniformity evaluation, thicker deposit was found on the bottom and sides of substrate, indicating the spatial variation of deposit thickness was governed by the tertiary current distribution which is related to $Cu^{2+}$ transport. The surface morphology of Cu deposit inside photo-resist pattern was controlled by organic additives in the electrolyte as it led to the flatter top surface compared to convex surface which was observed in the deposit grown without organic additives.

• Analytical Science and Technology
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• v.23 no.4
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• pp.331-346
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• 2010

Perfluorinated compounds have characteristics of resistance to heat, acidic, basic conditions and also resist water, oil, grease, pollutant. Futhermore they are used by various industrial material, nowadays, they produced in large scale for indutrial and commercial areas. However, they also resist metabolizing and degrading in environmental system (plant, animal, even human body). Moreover, in animal's bodies, PFCs can be accumulated in organ (eg; liver) and lead to liver cell necrosis even oncogenesis. Perfluorinated compounds are newly registered as new persistent organic pollutants (POPs) on Stockholm convention in 2009. Therefore necessity for analytical methodology for determination of PFCs in various environmental samples is even more increased. This study discussed sample preparation and instrumental conditions for the analysis of PFCs in environmental and biota samples.

• Journal of the Korea Fashion and Costume Design Association
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• v.13 no.3
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• pp.149-163
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• 2011

Hanjisa(Korean paper yarn), a new material made from the traditional Korean paper, has been developed through local R&D efforts, reflecting the current trend highly valuing environmental friendly. This new material is considered suitable for the 21C lifestyle and culture pursuing improved quality of human life and the environment. Therefore, this study aims to widely make known the originality and functions of the environmentally friendly Korean paper yarn, as well as to increase its commercial value. Furthermore, a new category of apparel design is presented by studying painting dyeing based on transformational tuck techniques and wax resist dyeing with formative features of repeated lines and rhythms of shells in order to implement three-dimensional and decorative artistic expressions. The texture of the Korean cotton paper yarn was particularly suitable to employ tuck and dyeing techniques Which express formative features of shell. Also, the material was useful for expressing the three-dimensional feelings with repeated curves and cross sections of shells. Moreover, paraffin resist dyeing and stitch techniques were used in order to avoid monotony and the images of shells visually materialized. Through the results stated above, this study could explore how to overcome obstacles to globalization of the Korean modern apparel such as its uniqueness, limit of materials or absense of internationality by applying modern design to the Korean paper fabrics. In the future, it is expected that more manufactures could produce and supply the new materials so as to make widely known the originality of the Korean paper fabrics and develop the material into a popular organic product fitting the modern lifestyle.

• Macromolecular Research
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• v.16 no.1
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• pp.31-35
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• 2008

Photoreactive polymers as a color filter resist containing both photoreactive acrylate and cinnamate double bonds were synthesized usin two step reactions. The chemical structures of the synthesized polymers were confirmed by $^1H$-NMR and FT-IR spectroscopy. The photoreactive polymers were quite soluble in most common organic solvents and produced excellent quality thin films by spin-coating. The photocuring kinetics of the acrylate and cinnamate double bonds were examined by FT-IR and UV- Vis spectroscopy, which confirmed the excellent photoreactivity of both the acrylate and cinnamate double bonds in the polymers. Upon UV irradiation, photocuring was almost completed within approximately 5 min, irrespective of the type of the prepolymers. The polymers also exhibited superior thermal stability, showing little change in transmittance in the visible region even after heating to $250^{\circ}C$ for one hour. Photolithographic micropatterns could be obtained with a resolution of a few microns.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.84-84
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• 2010

In this study, we report on the novel lithographic patterning method to fabricate organic-semiconductor devices based on photo and e-beam lithography with well-known silicon technology. The method is applied to fabricate pentacene-based organic field effect transistors. Owing to their solubility, sub-micron sized patterning of P3HT and PEDOT has been well established via micromolding in capillaries (MIMIC) and inkjet printing techniques. Since the thermally deposited pentacene cannot be dissolved in solvents, other approach was done to fabricate pentacene FETs with a very short channel length (~30nm), or in-plane orientation of pentacene molecules by using nanometer-scale periodic groove patterns as an alignment layer for high-performance pentacene devices. Here, we introduce the atomic layer deposition of $Al_2O_3$ film on pentacene as a passivation layer. $Al_2O_3$ passivation layer on OTFTs has some advantages in preventing the penetration of water and oxygen and obtaining the long-term stability of electrical properties. AZ5214 and ma N-2402 were used as a photo and e-beam resist, respectively. A few micrometer sized lithography patterns were transferred by wet and dry etching processes. Finally, we fabricated sub-micron sized pentacene FETs and measured their electrical characteristics.

• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.175-184
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• 2012

This study was conducted to develop new mattress systems with vegetation base materials for protecting stream bank and rapid rehabilitation. Vegetation base materials are primarily compounded with fine soil, organic composts and peat moss as plant fibers, a water retainer and a soil improver. Peat moss can usually provide necessary natural fibers and organic materials in soil. Especially, peat moss can absorb up to 25 times its own weight in water and is therefore valued as a water retainer to prevent drying effect of vegetation base materials which can harm the growth of vegetation in mattresses. Normally mattress systems resist the lateral earth pressures or stream power by their own weight. Therefore, filled materials must have suitable weight, compressive strength and durability to resist the loading, as well as the effects of water and weathering. In this project, 100 to 200-mm clean, hard stones were basically specified, and about 50-mm rubbles were also used. Test application of new mattress system carried out in the stream bank of a small stream in the Gwangreung experimental forest, belonging to Korea Forest Research Institute (KFRI) in December 16th, 2006. As a result of the monitoring of vegetation coverage of test application plots (each plot size is 4 by 2 m), the coverage of all plots reached 100% in the end of May, 2007 (approximately 50 days passed after the first gemination of vegetation). The coverage of the plots using big hard stones and organic composts and the plots containing peat moss increased more rapidly. The results show that peat moss is effective to retain soil moisture and establish more sound environment for vegetation gemination.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.230-234
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• 2011

In this work, the primary material for a single layered hardmask which can afford a spin-on process was prepared by the minture of organic and inorganic sources. The preparation of hybrid polymer was attempted by esterification from silanol terminated siloxane compounds and acetonide-2,2-bis(methoxy)propionic acid. The optical, thermal and morphological properties of the test hardmask film was examined in terms of cross-linking agent and additives. In addition, the etch rate of hardmask film and photo resist layer were compared. The hybrid polymer prepared from organic and inorganic materials was found to be useful for hardmask film to form the nano-patterns.

• Journal of the Korean Vacuum Society
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• v.20 no.1
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• pp.63-69
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• 2011

In this study, we report on the novel lithographic patterning method to fabricate organic thin film field effect transistors (OTFTs) based on photo and e-beam lithography with well-known silicon technology. The method is applied to fabricate pentacene-based organic field effect transistors. Owing to their solubility, sub-micron sized patterning of P3HT and PEDOT has been well established via micromolding in capillaries and inkjet printing techniques. Since the thermally deposited pentacene cannot be dissolved in solvents, other approach was done to fabricate pentacene FETs with a very short channel length (~30 nm), or in-plane orientation of pentacene molecules by using nanometer-scale periodic groove patterns as an alignment layer for high-performance pentacene devices. Here, we introduce $Al_2O_3$ film grown via atomic layer deposition method onto pentacene as a passivation layer. $Al_2O_3$ passivation layer on OTFTs has some advantages in preventing the penetration of water and oxygen and obtaining the long-term stability of electrical properties. AZ5214 and ma N-2402 were used as a photo and e-beam resist, respectively. A few micrometer sized lithography patterns were transferred by wet and dry etching processes. Finally, we fabricated micron sized pentacene FETs and measured their electrical characteristics.

• The Microorganisms and Industry
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• v.19 no.2
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• pp.34-41
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• 1993

Industrial strain improvement is concerned with developing or modifying microorganisms used in production of commercially important fermentation products. The aim is to reduce the production cost by improving productivity of a strain and manipulating specific characteristics such as the ability to utilize cheaper raw materials or resist bacteriophages. The traditional empirical approach to strain improvement is mutation combined with selection and breeding techniques. It is still used by us to improve the productivity of organisms in amino acids, organic acids and enzymes production. The breeding of high L-lysine-producing strain Au112 is one of the outstanding examples of this approach. It is a homoserine auxotroph with AEC, TA double metabolic analogue resistant markers. The yield reaches 100 g/l. Besides, the citric acid-producing organism Aspergillus niger, Co827, its productivity reaches the advanced level in the world, is also the result of a series mutations especially with $^60Co{\gamma}$-radiation. The thermostable .alpha.-amylase producing strain A 4041 is the third example. By combining physical and chemical mutations, the strain A 4041 becomes an asporogenous, catabolite derepressed mutant with rifamycin resistant and methionine, arginine auxotroph markers. The .alpha.-amylase activity reaches 200 units/ml. The fourth successful example of mutation in strain improvement is the glucoamylase-producing strain Aspergillus niger SP56, its enzyme activity is 20,000 units/ml, 4 times of that of the parental strain UV-11. Recently, recombinant DNA approach provides a worthwhile alternative strategy to industrial strain improvement. This technique had been used by us to increase the thermostable .alpha.-amylase production and on some genetic researches.