• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.6
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• pp.9-16
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• 2000

In order to achieve stiction-free polysilicon surfaces, we have suggested a new class of chemical coating precursors and confirmed their excellent characteristics. The strategy is to adopt dialkyldichlorosilanes (DDS, $R2SiCl_2$) instead of monoalkyltrichlorosilanes (MTS, $RSiCl_3$) such as octadecyltrichlorosilane (OTS) or 1H,1H2H,2H-perfluorodecyltrichlorosilane (FDTS). Dichlorodimethylsilane (DDMS, $(CH_3)2SiCl_2$) in this study is commercially available DDS with two short chains. DDMS in aprotic media spontaneously deposits on the hydrophilic polysilicon surface, which is completely changed to hydrophobic one. When polysilicon surface is exposed to DDMS solution at room temperature, anti-stiction property and hydrophobicity are clearly comparable to FDTS. DDMS is even superior to MTS in reliability and easy handling, which provides high yield. Since interactions among precursor molecules are reduced, conglomeration both in homogeneous solution and on surface can be effectively avoided. Even the cantilevers of 3 mm in length can be protected successfully from the stiction and the final quality of the modified surfaces is much less dependent on temperature. And no difference was found between the processes in ambient environment and in dry box. In addition, DDMS has advantages of remarkably reduced process time and low cost.

• The Korean Journal of Nuclear Medicine
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• v.3 no.1
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• pp.73-82
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• 1969

The newly developed diagnostic method with application of $^{113}Sn-^{113m}In$ cow system ($^{113}Sn:\;T\frac{1}{2}$ 118 days, $^{113m}In:\;T\frac{1}{2}$ 1.7 hrs, 390 Kev, Single ${\gamma}$) has the remarkable advantages such as increased diagnostic ability by single large dose administration of $^{113m}In$ with no subsequent radiation hazard and shortened examining time. We reformed the research of following scope with the use of developed $^{113}Sn-^{113m}In$ cow (25 mCi) generator: The sizes of particles produced under various conditions were investigated, and possibility for application to the scannings of various organs such as brain, liver, lung, bone marrow and blood pool etc. were studied. Results: $^{113m}InCl_3$ solution eluted from diluted HCl solution (pH 1.5) passed through $^{113}Sn-^{113m}In$ generator, and there can be produced various sized particles of colloidal indium. And there observed the state of distribution of $^{113m}In$ in each organ which showed many differences according to the particle sizes of colloidal indium. The results are stated as follows: 1. The adjustment of pH is the most important factor in making the desirable particle size of colloidal indium. The colloid for blood pool showed the highest level as 7.1%/gm blood, at pH 1.7, the colloid of pH 3.5 for liver scanning showed the highest level, 88.4%, in the liver, the colloid pH 6 showed the highest level, 3.1%, in the spleen, and the colloid of pH 11.0 showed the highest level, 85.3%/gm, in the lung. 2. The colloid for liver scanning made with NaCl-NaOH system showed the highest liver uptake at pH 7.2, and at either higher or lower pH than 7.2 showed decrease of liver uptake more or less. 3. The activity of $^{113m}In$ eluted through $^{113}Sn-^{113m}In$ generator indicated over 90% in the initial 4 ml, and particularly 88.1%-86.0% in the initial 2 ml. 4. The incubation time, tempertaure and mechanical irritation related to colloid formation and coating of colloid were not the definite condition of influence.

• Korean Chemical Engineering Research
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• v.57 no.3
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• pp.413-419
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• 2019

In the recent, as a world demand of energy resources has been transformed from fossil fuels to hydrogen-based clean energy resources, a huge attention has been attracted to increase the performance and decrease a production cost of core materials in fuel cell technology. The utilization of reinforced composite membranes as electrolytes in the polymer electrolyte membrane fuel cells can reduce the use of high cost perfluorosulfonic acid (PFSA), mitigate the cell impedance, and improve the dimensional stability as well as the interfacial stability, giving rise to achieve both an improved performance and a reduction of production costs of the fuel cell devices. In this study, we investigate the effects of physical characteristics and cell performances according to the various ionomer solvents in the solution based manufacturing process of reinforced composite electrolyte membrane.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.1 s.55
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• pp.45-51
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• 2006

In the field of makeup cosmetics, especially, powder-based foundations such as two-way cake, pact and face powder, the quality of which is known to be strongly influenced by the properties of powder, surface treatment technology is widely used as a method to improve the various characteristics of powder texture, wear properties, dispersion ability and so on. The two-way cake or pressed-powder foundation is one of the familiar makeup products in Asian market for deep covering and finishing purpose. In spite of the relent progress in surface modification method such as composition of powders with different characteristics and application of a diversity of coating ingredient (metal soap, amino acid, silicone and fluorine), this product possess a technical difficulty to enhance both of the adhesion power and spreadability on the skin in addition to potential claim of consumer about heavy or thick feeling. This article is covering the preparation and coating method of nano-vesicle that mimic the double-layered lipid lamellar structure existing between the corneocytes of the stratum corneum in the skin for the purpose of improving both of two important physical characteristic of two-way cake, spreadability and adhering force to skin, and obtining better affinity to skin. Nano-vesicle was prepared using the high-pressure emulsifying process of lecithin, pseudo ceramide, butylene glycol and tocopheryl acetate. This nano-sized emulsion was added to powder-dispersed aqueous phase together with bivalent metal salt solution and then the filtering and drying procedure was followed to yield the nano-vesicle coated powder. The amount of nano-vesicle coated on the powder was able to regulated by the concentration of metal salt and this novel powder showed the lower friction coefficient, more uniform condition of application and higher adhesive powder comparing with the alkyl silane treated powder from the test result of spreadability and wear properties using friction meter and air jet method. Two-wav cake containing newly developed coated powder with nano-vesicle showed the similar advantages in the frictional and adhesive characteristics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.1
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• pp.7-15
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• 2004

The ferroelectric SBT thin films as a material of capacitors for non-volatile FRAMs have some problems that its remanent polarization value is relatively low and the crystallization temperature is quite high abovc 80$0^{\circ}C$. Therefore, in this paper, SBTN solution with S $r_{0.9}$B $i_{2.1}$T $a_{1.8}$N $b_{0.2}$$O_{9}$ composition was synthesized by sol-gel method. Sr(O $C_2$ $H_{5}$)$_2$, Bi(TMHD)$_3$, Ta(O $C_2$ $H_{5}$)$_{5}$and Nb(O $C_2$ $H_{5}$)$_{5}$ were used as precursors, which were dissolved in 2-methoxyethanol. SBTN thin films with 200 nm thickness were deposited on Pt/Ti $O_2$/ $SiO_2$/Si substrates by spin-coating. UV-irradiation in a power of 200 W for 10 min and rapid thermal annealing in a 5-Torr-oxygen ambient at 76$0^{\circ}C$ for 60 sec were used to promote crystallization. The films were well crystallized and fine-grained after annealing at $650^{\circ}C$ in oxygen ambient. The electrical characteristics of 2Pr=11.94 $\mu$C/$\textrm{cm}^2$, Ps＋/Pr＋=0.54 at the applied voltage of 5 V were obtained for a 200-nm-thick SBTN films. This results show that 2Pr values of the UV irradiated and rapid thermal annealed SBTN thin films at the applied voltage of 5 V were about 57% higher than those of no additional processed SBTN thin films. thin films.lms.s.s.

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.740-744
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• 2005

Perovskite-type oxide $La_{1-x}Sr_xCo_{1-y}Fe_yO_{3-{\delta}}$ sols were prepared by sol-gel method using $La(NO_3)_3{\cdot}xH_2O$, $Sr(NO_3)_2$, $Co(NO_3)_2{\cdot}6H_2O$ and $Fe(NO_3)_3{\cdot}9H_2O$ as starting materials. The properties of the perovskite-type oxide sols were investigated by viscometer, FT-IR, TG-DTA and XRD. The prepared sols showed 1.16 cp in average viscosity, and a strong acidic condition of pH 0.5, irrespective of composition of the starting materials. The viscosity of sols at the same volume decreases, but the gelation time of sols, at which the sol viscosity increases rapidly, increases when increasing La concentration in composition of starting materials.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.101-108
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• 2005

Because the stone cultural properties located outdoors, they have been altered and deteriorated in external appearance due to environmental factors such as acid rain, extreme change in temperature, and salts. Damage to stone cultural properties is accelerated particularly due to recent industrial development and environmental pollution. An experimental study was conducted to evaluate the effect of environmental contaminants on the weathering of granite. And as part of the developing of conservation method, $TiO_2$ catalyst was prepared and tested. When fresh granite was dipped into the salt and acid solutions, dissolution rate of eight minerals (Si, Mg, Ca, Na, K, Fe, Mn, Al) are abruptly increased at initial stage of reaction and then increased steadily until 100 cycles. After salt and acid solution experiments, the mineral compositions of the granite surface were lower then that of the fresh granite and density of the weathered granite was steadily decreased from $2.60\;g/cm^3$ to $2.56\;g/cm^3$, but Poissions ratio and absorption ratio were slightly increased. It was expected at stone cultural assets could be weathered by salts and acid rain. In the case of $TiO_2$ was coated to the granite, the dissolution rate of minerals and absorption ratio of $TiO_2$ coated granite were decreased. Therefore, the $TiO_2$ coating method tested in this study considered to be a viable method to assist in the conservation of stone cultural properties from environmental contaminants.

• The Journal of the Korea Contents Association
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• v.14 no.4
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• pp.389-396
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• 2014

This study was conducted as the basic research for the replacement of Blast Furnace Slag, Red Mud, Silica Fume, etc., with cement as a solution to the problems arising from the global warming caused by the generation of $CO_2$, and conducted the experimental review to examine the feasibility of matrix having properties identical to those of cement by using the Blast Furnace slag, Red mud, Silica fume, and alkali-activator. For this, by using the the inorganic binder, such as Blast Furnace Slag, Red Mud, Silica Fume, etc., and NaOH, $Na_2SiO_3$ and others as the cement substitute material, the strength characteristic according to the mixture time variation was performed in the tentative experiment. Based on the preceding experiment, this study performed the experiment to analyze the strength properties of hardener through the curing by air-dry temperature, curing by temperature in water, coating curing, and Korean paper curing. For the water curing at $80^{\circ}C$, the compressive strength and flexural strength were found to be the most excellent at the age of the 28th day, and furthermore, it was found that the non-cement hardener could be made, which is considered to affect the production of eco-friendly concrete.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.6
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• pp.277-281
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• 2009

Superhydrophobic $SiO_2$ thin films were successfully fabricated on a glass substrate by sol-gel method. To fabricate $SiO_2$ thin film with a high roughness, $SiO_2$ nano particles were added into tetraethoxysilane (TEOS) solution. The prepared $SiO_2$ thin film without an addition of $SiO_2$ nano particles showed a very flat surface with ca. 1.27 nm of root mean square (RMS) roughness. Otherwise, the $SiO_2$ thin films fabricated by using coating solutions added $SiO_2$ nano particles of 1.0, 2.0 and 3.0 wt% showed a RMS roughness of ca. 44.10 nm, ca. 69.58 nm, ca. 80.66 nm, respectively. To modify the surfaces of $SiO_2$ thin films to hydrophobic surface, a hydrophobic treatment was carried out using a fluoroalkyltrimethoxysilane (FAS). The $SiO_2$ thin films with a high rough surface were changed from hydrophilic to hydrophobic surface after the FAS treatment. Especially, the prepared $SiO_2$ thin film with a RMS roughness of 80.66 nm showed a water contact angle of $163^{\circ}$.

• Journal of the Korean Ceramic Society
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• v.41 no.2
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• pp.170-175
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• 2004

The ferroelectric (Y $b_{x}$ $Y_{1-x}$)Mn $O_3$ thin films were fabricated by sol-gel method using Y-acetate, Yb-acetate, and Mn-acetate as raw materials. The stable (Y $b_{x}$ $Y_{1-x}$)Mn $O_3$ precursor solution (sol) was prepared through the reflux process with acetylaceton as a catalyst and coated on Si(100) substrate by spin coating. The heat treatment temperature and, Rw ($H_2O$/alkoxide moi ratio) dependence on crystallinity of thin films were studied. The lowest temperature for obtaining YbMn $O_3$phase and the optimum heat-treatment conditions were proved as at 7$50^{\circ}C$ and 80$0^{\circ}C$, respectively. The hexagonal YbMn $O_3$with c-axis preferred orientation could be obtained at Rw=1 condition. The remanent polarization for the thin films of x=0 or 1 was about 200 nC/㎤ while, for the specimens ot 0< x< 1, were 50∼100 nC/$\textrm{cm}^2$.