• Journal of Korea Port Economic Association
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• v.25 no.4
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• pp.107-130
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• 2009

Future of Busan New Port may depend even on the efficient use of the port hinterland. Accordingly, selection of which industry according to which standard in the port hinterland is another task. In order to solve this problem, it analyzed the structure in international division of labor with China and Japan, which are possessing considerable portion in the trading volume with our country, and the export-import structure of Busan Port against China and Japan, by using RCA index and GL index as well as export-import results. In addition to this, the proper industry was selected on the basis of 10 strategic industries for development in Busan. According to the analytical results, the industries, which will be induced in the hinterland of Busan New Port, include textile clothing, pulp printing matter, jewelry, basic metal nonmetallic product, machine lectric product, automobile, shipbuilding, optics accurate machinery medical treatment musical instrument, nano material, fuel battery, aerospace and intelligent robot.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1754-1759
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• 2008

To produce plastic parts that have fine pattern through conventional injection molding, a lot of difficulties follow. Therefore, rapid heating and cooling methods are good candidates for manufacturing injection-molded parts with micro/nano patterns. In this study, we adopted the E-Mold patent technology. The mold for E-Mold technology has a separate heated core with micro heaters. It is very important to optimize the lay-out of the heaters in heated core because it influences both control and distribution of mold temperature. We developed a optimization method of heating line lay-out by using commercial softwares and compared the output with the experimental results. We used Pro-Engineer Wildfire 2.0 for the mold design, ICEMCFD for mesh generation, and FLUENT for heat transfer simulation. The simulation results showed the temperature profile from $60^{\circ}C$ to $120^{\circ}C$ or $180^{\circ}C$ during heating and cooling process which were compared with the injection molding experiments. We concluded that the simulation could well explain the experimental results. It was shown that the E-Mold optimization design for heater lay-out could be available through the simulation.

• Polymer(Korea)
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• v.28 no.5
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• pp.382-390
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• 2004

One of the significant natural bioactive materials is demineralized bone particle (DBP) whose has a powerful induce. of new bone growth. In this study, we developed the DBP loaded poly-lactide (PLA) and poly(L-lactide-co-glycolide) (PLGA) scaffolds for the possibility of the application of the tissue engineered bone. PLA/DBP and PLGA/DBP scaffolds were prepared by solvent casting/salt leaching method and were characterized by porosimeter, scanning electron microscopy. BMSCs were stimulated by osteogenic medium and characterized by histological stained Wright-Giemsa, Alizarin red, von Kossa, and alkaline phosphate activity (ALP). DBP impregnated scaffolds with BMSCs were implanted into the back of athymic nude mouse to observe the effect of DBP on the osteoinduction compared with control scaffolds. It can be observed that the porosity was above $90.2\%$ and the pore size was above 69.1$\mu$m. BMSCs could be differentiated into osteoprogenitor cells as result of wright-giemsa, alizarin red, von Kossa and ALP staining. In in vivo study, we could observed calcification region in PLA/DBP and PLGA/DBP groups, but calcification did not occur almost in control scaffolds. From these results, it seems that DBP as well as BMSCs play an important role for bone induction in PLA/DBP and PLGA/DBP scaffolds.

• Polymer(Korea)
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• v.29 no.5
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• pp.451-456
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• 2005

In the field of designing of nano-fillers of polyimide nanocomposites, the two strategic points are the heat-resistance and compatibility with polyimide, a matrix polymer. In this study, we designed oligo(amic acid) having alkyl side chains and terminal amine groups to satisfy previous requirements and studied the modification of surface of layered silicates. Oligo(amic acid)s were prepared by the reaction of diamine monomers and PMDA and their molecular weight was controlled in about 2000g/mol. After that, acidification and ion exchange reaction led to the high-temperature organophilic layered silicate (OLS). XRD pauerns of OLS showed the more increased gallery spacing by $4{\AA}$ than that of the pristine layered silicate and the initial decomposition temperatures of OLS were in above $280^{\circ}C$. The polyimide nanocomposite films based on heat resistant OLS showed that the OLSs were well dispersed through the matrix and their CTEs showed a decrease of $26\%$ compared with pristine polyimide films.

• Journal of the Korean Vacuum Society
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• v.20 no.3
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• pp.225-232
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• 2011

Reactive ion etching (RIE) technique for maskless surface texturing of mc-silicon solar wafers has been applied and succeed in fabricating a grass-like black-silicon with an average reflectance of $4{\pm}1%$ in a wavelength range of 300~1,200 nm. In order to investigate the optimized texturing conditions for mass production of high quantum efficiency solar cell Surface characteristics such as the spatial distribution of average reflectance, micrscopic surface morphology and minority carrier lifetime were monitored for samples from saw-damaged $15.6{\times}15.6\;cm^2$ bare wafer to key-processed wafers as well as the mc-Si solar cells. We observed that RIE textured wafers reveal lower average reflectance along from center to edges by 1% and referred the origin to the non-uniform surface structures with a depth of 2 times deeper and half-maximum width of 3 times. Samples with anti-reflection coating after forming emitter layer also revealed longer minority carrier lifetime by 40% for the edge compared to wafer center due to size effects. As results, mc-Si solar cells with RIE-textured surface also revealed higher efficiency by 2% and better external quantum efficiency by 15% for edge positions with higher height.

• Journal of the Korean Vacuum Society
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• v.19 no.6
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• pp.442-452
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• 2010

Our team carried out a new program for public engagement on nanotechnology in Korea. We chose 22 monitors, who majored in science or technology and graduated from universities long time ago. Most of them were married and housewives. This 'focus group' had not only general knowledge about science or technology but also much interest in social activities. The 167 nanoproducts to be monitored were for daily life, e.g. home appliances (washing machine, refrigerator, water purifier, etc), clothing, cosmetics, food, toy, and others. And the period of it was one month. The monitors had a sheet with 10 questions, and filled them out in essay form. All of them submitted 2~3 sheets every weekend to our team. Before monitoring, our team had a meeting for introduction and explanation about the potential risk of nanotechnology as well as benefits from it. Another meeting was held after finishing monitoring to share their experience one another. The main results of the monitoring were as follows: the number of nanoproducts describing both the definition of 'nano' and the size of nanomaterials was just 2 (1.2%) the number of them explaining the technical methods enough was 15 (9/0%) the number of them accounting for the reason of functional improvement enough was 14(8.4%); the number of them doubtful as if there would be exaggeration or false knowledge was 27 (16.2%); the number of them commenting potential hazards to human health or environment was almost zero; the number of them describing about safety certification acceptable was 9 (5.4%). The monitors made a proposal containing recommendation to Government and industry. The contents were as follows: industry should make the manual in detail and correctly, Describe Certificate detailed and correctly, Do research on risk and toxicity continually, Educate employee about nanoproducts at consumer's center; Government should make indication of nanoproducts compulsory, Appoint Certificate Authority and make Certificate Mark guaranteeing the safety on nanoproducts, Make detailed explanation about nanoproducts compulsory.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.97-97
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• 2013

Recently, Cu2ZnSn(S,Se)4 (CZTSS), which is one of the In- and Ga- free absorber materials, has been attracted considerable attention as a new candidate for use as an absorber material in thin film solar cells. The CZTSS-based absorber material has outstanding characteristics such as band gap energy of 1.0 eV to 1.5 eV, high absorption coefficient on the order of 104 cm-1, and high theoretical conversion efficiency of 32.2% in thin film solar cells. Despite these promising characteristics, research into CZTSS based thin film solar cells is still incomprehensive and related reports are quite few compared to those for CIGS thin film solar cells, which show high efficiency of over 20%. I will briefly overview the recent technological development of CZTSS thin film solar cells and then introduce our research results mainly related to sputter based process. CZTSS thin film solar cells are prepared by sulfurization of stacked both metallic and sulfide precursors. Sulfurization process was performed in both furnace annealing system and rapid thermal processing system using S powder as well as 5% diluted H2S gas source at various annealing temperatures ranging from $520^{\circ}C$ to $580^{\circ}C$. Structural, optical, microstructural, and electrical properties of absorber layers were characterized using XRD, SEM, TEM, UV-Vis spectroscopy, Hall-measurement, TRPL, etc. The effects of processing parameters, such as composition ratio, sulfurization pressure, and sulfurization temperature on the properties of CZTSS absorber layers will be discussed in detail. CZTSS thin film solar cell fabricated using metallic precursors shows maximum cell efficiency of 6.9% with Jsc of 25.2 mA/cm2, Voc of 469 mV, and fill factor of 59.1% and CZTS thin film solar cell using sulfide precursors shows that of 4.5% with Jsc of 19.8 mA/cm2, Voc of 492 mV, and fill factor of 46.2%. In addition, other research activities in our lab related to the formation of CZTS absorber layers using solution based processes such as electro-deposition, chemical solution deposition, nano-particle formation will be introduced briefly.

• Applied Chemistry for Engineering
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• v.31 no.2
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• pp.179-186
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• 2020

In this study, chitosan/zeolite composites were prepared by using basalt-based zeolite impregnated with aqueous chitosan solution for the adsorptive separation of CO₂. The prepared composites were characterized by scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption analysis. In addition, the adsorption equilibrium isotherms for CO₂ and N₂ were measured at 298 K using a volumetric adsorption system, and the results were analyzed by applying adsorption isotherm equations (Langmuir, Freundlich, and Sips) and energy distribution function. It was found that CO₂ adsorption capacities were well correlated with the structural characteristics of chitosan and zeolite, and the ratio of elements [N/C, Al/(Si + Al)] formed on the surface of the composite. Moreover, the CO₂/N₂ adsorption selectivity was calculated under the mixture conditions of 15 V : 85 V, 50 V : 50 V, and 85 V : 15 V using the Langmuir equation and the ideal adsorption solution theory (IAST).

• YAKHAK HOEJI
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• v.50 no.4
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• pp.272-277
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• 2006

This study was undertaken to determine whether the 9 herbal complex induces apoptosis in human breast cancer MCF-7 cells and adriamycin-resistant MCF7/adR cells. Ethanol extracts of Bojungbangamtang (BBTE) and acidic polysaccharide of Red Ginseng (GIN) induced cell death in both MCF-7 and MCF7/adR cells. Ethanol extracts of Bojungbangamtang and acidic polysaccharide of Red Ginseng also induced $G_2/M$ cell cycle arrest and increased TUNEL positive cells in MCF7/adR cells. In addition, flow cytometric analysis revealed the decreased expression of P-glycoprotein (P-gp) in ethanol extracts of Bojungbangamtang and acidic polysaccharide of Red Ginseng treated MCF7/adR cells. Similarly, decreased protein levels of P-glycoprotein and multidrug resistance associated proteins-1 were also determined by immunocytometry in ethanol extracts of Bojungbangamtang treated MCF7/adR cells. Taken together these data indicate that ethanol extracts of Bojungbangamtang and acidic polysaccharide of Red Ginseng inhibit the function of ABC transporters such as multi drug resistance associated proteins (MRPs) and P-glycoprotein as well as induce apoptosis in MCF7/adR cells. Thus, these data suggest that ethanol extracts of Bojungbangamtang and polysaccharide of Red Ginseng can be candidates for the treatment of multidrug-resistant MCF7/adR cells.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.6
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• pp.559-569
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• 2018

Catalytic supports made of carbon have many advantages, such as high coking resistance, tailorable pore and surface structures, and ease of recycling of waste catalysts. Moreover, they do not require pre-reduction. In this study, ash-free coal (AFC) was obtained by the thermal extraction of carbonaceous components from raw coal and its performance as a carbon catalytic support was compared with that of well-known activated carbon (AC). Nickel was dispersed on the carbon supports and the resulting catalysts were applied to the steam reforming of toluene (SRT), a model compound of biomass tar. Interestingly, nickel catalysts dispersed on AFC, which has a very small surface area (${\sim}0.13m^2/g$), showed higher activity than those dispersed on AC, which has a large surface area ($1,173A/cm^2$). X-ray diffraction (XRD) analysis showed that the particle size of nickel deposited on AFC was smaller than that deposited on AC, with the average values on AFC ${\approx}11nm$ and on AC ${\approx}23nm$. This proved that heteroatomic functional groups in AFC, such as carboxyls, can provide ion-exchange or adsorption sites for the nano-scale dispersion of nickel. In addition, the pore structure, surface morphology, chemical composition, and chemical state of the prepared catalysts were analyzed using Brunauer-Emmett-Taylor (BET) analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, and temperature-programmed reduction (TPR).