• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.6
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• pp.816-822
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• 2012

Volatile components of acorn crude starches and gel powder created from them were analyzed by Gas Chromatograph-Ion Mobility Mass Spectrometry (GC-IMS). Crude starches were obtained from acorns harvested in South Korea (KAS), China (CAS), and North Korea (NAS). The principal component analysis (PCA) of each volatile component exhibited a significant contribution of PC 1 showing up to 60.5%. The acorn crude starch from KAS could be distinguished from crude starch from China by PC 1 (p<0.05). However, NAS and CAS could not be segregated statistically by the PC 1 component. PC 2, which exhibited 22.8% contribution, of KAS, also showed a meaningful difference (p<0.05) from those of CAS and NAS, making it possible to distinguish domestic acorn starch from imports.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.187-194
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• 2005

A PC-based 8-channel seismic system has been developed and applied for bedrock mapping in near shore environment. The system is composed of an analog signal processor and an A/D converter installed on the computer, and a streamer with the group interval of 5 meters. The system is accomplished with a data acquisition program which controls the system and a data processing software. With the PC-based shallow marine seismic survey system high-resolution 2-D marine seismic profiles which have high S/N ratios can be obtained after appropriate data processing.

• Macromolecular Research
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• v.17 no.12
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• pp.1021-1024
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• 2009

We successfully prepared high-flow polycarbonate (PC) by blending commercial PC with a low molecular weight PC oligomer. The oligomer was synthesized by the addition of a large quantity of mono functional phenol groups, and the chain end group was reacted with p-tertiary butyl phenol (PTBP) to block the reactivity. The viscosity average molecular weight ($M_v$) for the oligomer was about 4,000-5,000 g/mol, compared to ~19,000 g/mol for the PC blend obtained by blending 10 wt% of the prepared oligomer with the commercial grade PC ($M_v$ of 21,000 g/mol). The blended PC had a melt flow index of 45, which is 2.5 times higher, and a processing temperature that was $20^{\circ}C$ lower, than that of commercial grade PC having a similar $M_v$.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.4
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• pp.515-521
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• 2004

The catalytic oxidation of volatile organic compounds (methanol. acetaldehyde) has been characterized using the copper phthalocyanine catalyst in a fixed bed flow reactor under atmospheric pressure. The catalytic activity for pretreatment conditions was examined by this reaction system. The catalytic activity was ordered as follows: metal free-PC＜Cu ($\alpha$)-PC＜Cu ($\beta$)-PC The formaldehyde, carbon monoxide as a partial oxidation product of methanol and acetaldehyde over Cu ($\alpha$)-PC catalyst were detected and the conversions of methanol and acetaldehyde were accomplished above 95% over Cu ($\alpha$) -PC, Cu ($\beta$) - PC catalyst at 35$0^{\circ}C$. The pretreated metal free -PC, Cu($\alpha$)-PC, Cu($\beta$)-PC catalysts have been characterised by TGA, EA and XRD analysis. The catalytic activity pretreated with air and $CH_3$OH mixture (P-4) or air only (P-5) was very excellent. XRD and EA results showed that Cu($\alpha$)-PC, Cu($\beta$)-PC were destroyed an(1 new metal oxide such as CuO were formed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.177-178
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• 2020

In the construction industry, expectations for the Precast Concrete(PC) construction method are rising due to demands for high quality and productivity and social and environmental issues. However, although technical problems that occurred in the early stages of technology introduction have been solved, research related to proper construction management for PC construction methods has been relatively neglected and the advantages of PC construction methods have not been fully utilized. In this study, each group involved in PC works was surveyed to identify important management tasks affecting productivity of PC works to improve PC contruction management system. Based on factor analysis, 22 tasks were calssified into 5 management groups. The results of this study will be used to present a framework for the application of automation and information technology to improve the productivity of PC works.

• Macromolecular Research
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• v.14 no.4
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• pp.456-460
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• 2006

The electrical, morphological, and mechanical properties of poly carbonate (PC)/multi-walled carbon nan-otube (MWNT) composites were studied by electrical conductivity, electromagnetic interference shielding efficiency (EMI SE), scanning electron microscopy, and tensile strength measurements. In the electrical property analysis of the PC/MWNT composites, the percolation threshold of the PC/MWNT composites was observed between 1.5 and 2.5 wt% MWNT content. From the electrical conductivity and EMI SE studies, the theoretical values of the EMI SE were in good agreement with the experimental values of the EMI SE. From the morphology of the PC/MWNT composites, it was observed that MWNT is dispersed homogenously in the PC matrix. From the electrical conductivity and morphological studies, it was suggested that the percolation threshold of the PC/MWNT composites is related with the morphological results in that MWNT is apparently interconnected to form an electrical pathway. The mechanical properties of the PC/MWNT composites peaked at the MWNT content of 2.5 wt%.

• Membrane Journal
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• v.26 no.2
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• pp.126-134
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• 2016

To produce renewable biomethane from biogas, the properties of physical absorbents such as water, methanol, 1-methyl-2-pyrrolidone (NMP), poly(ethylene glycol) dimethylether (PEGDME), and propylene carbonate (PC) were studied, and PC was applied to membrane contactor systems. Among physical absorbents, PC exhibited a high contact angle of $58.3^{\circ}$ on polypropylene surface, and a PC/water mixture (5 wt%) increased the contact angle to $90^{\circ}$. Furthermore, the PC/water mixture presented higher $CO_2$ absorption capacities (0.148-0.157 mmol/g) than that of water (0.121 mmol/g), demonstrating a good property as an absorbent for membrane contactors. Actual operations in membrane contactors using the PC/water mixture resulted in $CO_2$ removal of 98.0-97.8% with biomethane purities of 98.5-98.3%, presenting a strong potential for biogas treatment. However, the PC/water mixture yielded moderate improved in $CO_2$ removal and methane recovery, as compared with water in the membrane contactor operation. This is originated from insufficient desorption processes to reuse absorbent and low $CO_2$ flux of the PC/water absorbent. Thus, it is requiring optimizations of membrane contactor technology including development of absorbent and improvement of operation process.

• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.284-293
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• 2000

For the artificial removal of air pollutants such as pesticides, environmental toxicants, and pathogenic microorganisms in the greenhouse or the living environment, the accelerated photodegradation and the biocidal effects of some photosensitizers (PS)/photocatalysts (PC) were tested under the sunlight and/or artificial light. The selected photosensitizers/photocatalysts included the semiconductors (PC-1 and PC-2), the oxidizers (PC-3, PC-4, PC-5 and PC-6), the aromatic ketone (PS-7) and the aromatic amine (PS-8). In the case of dichlorvos, all the photocatalysts selected showed more accelerated photodegradation than the control without photocatalysts under both the sunlight and artificial light. Whereas, only the photocatalyst PC-1 accelerated the degradation of methyl tert-butyl ether about 17 times more than the control under both the sunlight and artificial light. Procymidone was much more degraded by the photosensitizer PS-8 and the two photocatalysts (PC-1, PC-6) than by PS-7. In the preliminary experiments to diminish the population of the microorganisms in the air, the photocatalyst PC-1 added to the suspensions of Pseudomonas putida, Phytophthora capsici, and Salmonella typhimurium obviously inhibited the microbial growth under the artificial light. The photocatalyst PC-1 showed a bactericidal activity against Salmonella typhimurium spread on the nutrient broth agar medium. These results suggest that the photosensitizers/photocatalysis under the light can remove some air pollutants and hence they can be used to reduce the exposure of the workers in the horticultural facilities and/or the public in the environment to the harmful pollutants.

• The Korean Journal of Quaternary Research
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• v.25 no.2
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• pp.17-24
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• 2011

We investigated the variation of $CaCO_3$ contents in cores PC1 and PC2 recovered from the continental slope area of the Ulleung Basin in the East Sea. $CaCO_3$ contents of cores PC1 and PC2 varied between 0.6 and 17.2% and between 0.3 and 43.0%, respectively. $CaCO_3$ contents in the upper part of core PC1 corresponding to MIS 1 are less than 5%, whereas those in the lower part of MIS 2 are more than 10%. Such variation of $CaCO_3$ contents in core PC1 confirms the previous results of $CaCO_3$ studies in the East Sea. In core PC2, $CaCO_3$ contents of the upper part are similar to those of core PC1. However, $CaCO_3$ contents in the lower part of core PC2 are more than 40%. According to XRD operation and SEM examination, the high $CaCO_3$ contents in the lower part of core PC2 are more attributable to the authigenic carbonate minerals rather than the biogenic carbonate composition. Such abundant authigenic carbonate minerals are closely related to the dissociation of methan hydrates which were observed in the Ulleung Basin.

• Magazine of the Korea Concrete Institute
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• v.23 no.5
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• pp.49-51
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• 2011