• Journal of the Korean Chemical Society
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• v.42 no.1
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• pp.42-50
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• 1998

Titanium dioxide $(TiO_2)$ thin film samples were prepared by using spray pyrolysis methodology and were by using X-ray photoelectron spectroscopy and X-ray diffraction analysis. It was found that anatase prepared by the hydrolysis of titanium(Ⅳ) oxyacetylacetonate exhibited the largest specific surface area. The particle size increased with increasing temperature, while the thickness decreased. Titanium dioxide $(TiO_2)$ in the anatase form was prepared at $400^{\circ}C$ and the photoconductivity was determined using photocurrent measurements. Photoelectrochemical properties of the $TiO_2$-phthalocyanine system were measured in a three-electrode system. The photocurrent action spectrum in the visible region coincided with intrinsic absorption spectrum of phthalocyanine. The crystal structure of phthalocyanine is considered to be a very important property in the photogeneration phenomena.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.91-98
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• 2016

Linerboards have been produced by recycling recovered paper such as old corrugated containers(OCC). Usually linerboards produced during summer season show weak strength compared with those of produced during winter. In order to cope with the weak strength of linerboards produced during summer, and to confirm uniform quality, it is important to understand the seasonal effect on strength properties. Effect of pulping temperature of the OCC for linearboard production was investigated by controlling pulping temperatures at $18^{\circ}C$ and $51^{\circ}C$. Low pulping temperature ($18^{\circ}C$) caused more generation of fines in stock. Consequently retention and drainage of linerboard defibrated at high pulping temperature ($51^{\circ}C$) were better than those of $18^{\circ}C$. Strength properties of handsheet at low pulping temperature were higher than those of high pulping temperature and it could be confirmed that low pulping temperature during winter is one reason of seasonal variation of recycled linerboard strength. It is considered that surface modification of OCC fibers by harsh pulping action during winter caused increase of paper strength.

• Polymer(Korea)
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• v.27 no.3
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• pp.195-200
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• 2003

Alginate is a natural ionic polymer including numerous anionic groups and can be actuated by the ionic group under the electric field. The crosslinked alginate films were fabricated with CaCl$_2$. The thermal, mechanical and electroresponse properties of the films were investigated by thermogravimetric analysis, tensile and bending tests. The initial degradation and tensile strength increased according to the degree of crosslinking. Also, the swelling ratio of the films increased with decreasing degree of crosslinking and increasing pH due to free volume and electrostatic repulsion. The films actuated by an electric stimulus exhibited gentle and flexible action like a pendulum. In the electric field, the electric stimuli such as the applied voltage, ionic strength and kind of electrolyte solution had an effect on the electroresponse of the films. Alginate films with 5 wt% crosslinking agent showed the highest bending angle and reversible bending behavior. When the ionic strength of NaCl and KCl electrolyte solution was 0.1 M, the films showed the highest electroresponse. The bending behavior of the films increased with the applied voltage.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.4
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• pp.205-212
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• 2001

One of the important characteristics of biological systems os their ability to change im-portant properties in response to small environmental signals. The molecular mechanisms that biological molecules utilize to sense and respond provide interesting models for the development of "smart" polymeric biomaterials with biomimetic properties. An important example of this is the protein coat of viruses, which contains peptide units that facilitate the trafficking of the virus into the cell via endocytosis, then out of the endosome into the cytoplasm, and from there into the nucleus, We have designed a family of synthetic polymers whose compositions have been de-signed to mimic specific peptides on viral coats that facilitate endosomal escape. Our biomimetic polymers are responsive to the lowered pH whinin endosomes, leading to distruption of the en-dosomal membrane and release of important biomolecular druges such as DNA, RNA, peptides and proteins to the cytoplasm before they are trafficked to lysosomes and degraded by lysosomal en-zymes. In this article, we review our work on the design, synthesis and action of such smart, pH-sensitive polymers.

• Journal of the Korean Geotechnical Society
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• v.18 no.1
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• pp.71-78
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• 2002

This paper presents a back-calculation technique leer the prediction of the behavior of earth wall inserted in multi-layered soil deposit. The soil properties are back-calculated from the measured displacement at each construction stage and the behavior of earth wall far the next construction stage is predicted using back-calculated soil properties. For multi-layered soil deposit, the back-calculation would be very difficult due to the increase in the number of variables. In this study, to solve this difficulty, the back-calculation was performed successively from the lowest layer to the upper layers. An efficient elasto-plastic beam-column analysis was used for forward analysis to minimize the computation time of iterative back-calculation procedure. The coefficients of subgrade reaction and lateral earth pressure necessary for the formation of p-y curve were selected as back calculation variables, and to minimize the effect of abnormal behavior of the wall which might be caused by any unexpected action during construction, the difference between measured displacement increment and computed displacement increment at each construction stages is used as the objective function of optimization. The constrained sequential linear programming was used for the optimization technique to found values of variables minimizing the objective function. The proposed method in this study was verified using numerically generated data and measured field data.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.136-136
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• 2003

In fiber optic networks, system size and cost can be significantly reduced by development of optical components through planar optical waveguides. One important step to realize the compact optical devices is to develop planar optical amplifier to compensate the losses in splitter or other components. Planar amplifier provides optical gain in devices less than tens of centimeters long, as opposed to fiber amplifiers with lengths of typically tens of meters. To achieve the same amount of gain between the planar and fiber optical amplifier, much higher Er doping levels responsible for the gain than in the fiber amplifier are required due to the reduced path length. These doping must be done without the loss of homogeniety to minimize Er ion-ion interactions which reduce gain by co-operative upconversion. Sol-gel process has become a feasible method to allow the incorporation of Er ion concentrations higher than conventional glass melting methods. In this work, Er-doped $SiO_2$-A1$_2$ $O_3$ films were prepared by two different method via sol -Eel process. Tetraethylorthosilicate(TEOS)/aluminum secondary butoxide [Al (OC$_4$ $H_{9}$)$_3$], methacryloxypropylcnethoxysaane(MPTS)/aluminum secondary butofde [Al(OC$_4$ $H_{9}$)$_3$] systems were used as starting materials for hosting Er ions. Er-doped $SiO_2$-A1$_2$ $O_3$ films obtahed after heat-treating, coatings on Si substrate were characterized by X-ray din action, FT-IR, and N-IR fluorescence spectroscopy. The luminescence properties for two different processing procedure will be compared and discussed from peak intensity and life time.

• Journal of the korean society of oceanography
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• v.39 no.1
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• pp.72-95
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• 2004

The Yellow Sea is characterized by relatively shallow water depth, varying range of tidal action and very complex coastal geometry such as islands, bays, peninsulas, tidal flats, shoals etc. The dynamic system is controlled by tides, regional winds, river discharge, and interaction with the Kuroshio. The circulation, water mass properties and their variability in the Yellow Sea are very complicated and still far from clear understanding. In this study, an effort to improve our understanding the dynamic feature of the Yellow Sea system was conducted using numerical simulation with the ROMS model, applying climatologic forcing such as winds, heat flux and fresh water precipitation. The inter-annual variability of general circulation and thermohaline structure throughout the year has been obtained, which has been compared with observational data sets. The simulated horizontal distribution and vertical cross-sectional structures of temperature and salinity show a good agreement with the observational data indicating significantly the water masses such as Yellow Sea Warm Water, Yellow Sea Bottom Cold Water, Changjiang River Diluted Water and other sporadically observed coastal waters around the Yellow Sea. The tidal effects on circulation and dynamic features such as coastal tidal fronts and coastal mixing are predominant in the Yellow Sea. Hence the tidal effects on those dynamic features are dealt in the accompanying paper (Kim et at., 2004). The ROMS model adopts curvilinear grid with horizontal resolution of 35 km and 20 vertical grid spacing confirming to relatively realistic bottom topography. The model was initialized with the LEVITUS climatologic data and forced by the monthly mean air-sea fluxes of momentum, heat and fresh water derived from COADS. On the open boundaries, climatological temperature and salinity are nudged every 20 days for data assimilation to stabilize the modeling implementation. This study demonstrates a Yellow Sea version of Atlantic Basin experiment conducted by Haidvogel et al. (2000) experiment that the ROMS simulates the dynamic variability of temperature, salinity, and velocity fields in the ocean. However the present study has been improved to deal with the large river system, open boundary nudging process and further with combination of the tidal forcing that is a significant feature in the Yellow Sea.

• Microbiology and Biotechnology Letters
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• v.14 no.6
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• pp.473-478
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• 1986

In order to elucidate the patterns of natural oils and fats assimilation by microorganisms, lipases properties of yeast and bacterium strain, Torulopsis candia Y-128 and Acinetobacter calcoaceticus KB-2, which could assimilate palm oil efficiently, were investigated. T candida Y-128 attached palm oil droplets directly, and assimilated unsaturated fatty acid more easily than saturated acids liberated by the action of its lipase. Lipase of A. calcoaceticus KB-2 was extracellular and appeared quickly from the beginning of log phase of growth, whereas lipase of f candida Y-128 appealed intracellular. The lipases of two strains seem to be only enough to utilize the lipid materials for their own growth, without accumulation of lipases in the culture broth. Lipases of the strains have 1 (3-)-positional specificities on triglycerides. The patterns of palm oil assimilation showed that two strains attached droplets of lipid materials directly and split off fatty acids at 1 (3-)-position of triglycerides first, and assimilated the reaction products via fatty acids metabolic pathway.

• Journal of the Korean Institute of Oriental Medical Informatics
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• v.15 no.2
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• pp.77-91
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• 2009

Flowery Knotweed Root is the dried tuberous root of the knotweed family wheres Auriculate Swallowwort Root is the dried tuberous root of the swallowort family. Flowery Knotweed Root is also called Red Flowery Knotweed Root in China, which is dried root of Polygonum multiflorum THUMB. Chinese Flowery Knotweed Root is better known as the dried tuberous root belonging to the family Apocynaceae whereas White Flowery Knotweed Root in Korea is the dried tuberous root of Cynanchum wilfordii(Maxim) Hemsl. Up to now, while the dried root named Red Flowery Knotweed Root has been widely used in China, Auriculate Swallowwort Root has been widely used in Korea. Both the roots contrast in a striking way with the origin, shape, botanical names, other names, and chemical constituents, so administration and dosage without discrimination of both sides can be open to question. According to the literature, it is recorded that Flowery Knotweed Root and Auriculate Swallowwort Root are similar to the characteristics, properties, and actions. From this study, the result is as follows: 1. Flowery Knotweed Root and Auriculate Swallowwort Root are divided into the family Apocynaceae and the family Polygonaceae, respectively. Accordingly 2. Flowery Knotweed Root is in shape of an irregular spindle and looks reddish- brown or deep reddish-brown and the section is light yellowish-brown, while Auriculate Swallowwort Root looks yellowish-brown and the section is white or yellow. 3. Flowery Knotweed Root is reported by the Journal of the Crude Drug that the medicinals have not the same therapeutic action as Auriculate Swallowwort Root. It is recorded that the properties, channel entry, functions of Flowery Knotweed Root and Auriculate Swallowwort Root in literature have much in common. Many works on the roots of this plant has been used traditionally as a tonic are required of. In view of the results, Flowery Knotweed Root and Auriculate Swallowwort Root varies both in nature and in shape, so that the administration and dosage of the medicinals must be taken a prudent attitude.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.352-373
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• 2003

Rhamnose-rich (RROP-s) and fucose-rich (FROP-s) oligo-and polysaccharides were prepared and extensively characterised by physical and chemical procedures [1,2] and compared to L-fucose. Their biological properties were then studied on human skin fibroblast cell cultures, human skin explant cultures and on hairless rat skin, using a variety of cell-biological, biochemical and computerised morphometrical procedures. Among the most important properties we could establish, the following are of particular interest for the tretment and prevention of age-dependent modifications of human skin (loss of skin-tissue, cells and matrix, wrinkle formation and others) : stimulation of cell proliferation (by $^3$[H]-thymidine incorporation and the MTT test), scavenging of reactive oxygen species (ROS) using several different procedures, and protease (MMP-2 and MMP-9) down-regulation. A topical preparation, using RROP-s and FROP-s, and/or L-fucose, was shown to increase cell proliferation, dermal matrix synthesis, efficient scavenging of ROS-s and to increase also the thickness of dermal tissue when applied for 4 weeks on hairless rat skin, accompanied by the densification of collagen bundles as well as by an increase of elastin synthesis. Using fluorescent labeled FROPs, it could be shown that these oligosaccharides react with cell-membrane receptors and especially with the elastin-laminin-receptor and the fucose-mannose receptor, but they penetrate also in the cell nucleus, suggesting the possibility of a direct action on the regulation of gene expression. When applied to the human skin of a team of voluntary women encompassing all age-groups, the efficiency of FROP-containing preparation could be confirmed using indentometry and computerised evaluation of skin micro-relief, as well as evaluation of periorbital wrinkles. It appears therefore that these preparations correspond to all the requirements of active anti-aging principles.