• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.1
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• pp.75-84
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• 2012

Mechanized operation model and mechanical cultivation technology for winter barley, rye, Italian ryegrass and sudan grass wrap silage production system at the paddy field for cropping system was developed. Also, a series of experiment were performed and lots of data were collected and analyzed to develope mechanical technology, coverage area, and optimum size of the farm (break-even point) for wrap silage production system. The coverage area for winter barley or rye wrap-silage production system is determined around 61.9, 73.4, 77.5, 88.2 ha in the case of drill seeding and different ripening species by tractor power 50, 75, 100, 130 ps, respectably. The break-even point of the farming size is analyzed as 20 ha and its production cost is estimated around 367, 383, 430, 443 won/TDN-kg in the case of winter barley wrap-silage by tractor power 50, 75, 100, 130 ps, respectably. The break-even point of the farming size is analyzed as coverage area and its production cost is estimated around 237, 215 won/TDN-kg in the case of winter barley wrap silage and sudan grass by the tractor power 50, 100 ps, respectably.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.880-885
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• 2008

Spray pyrolysis was applied to prepare spherical silica particles with mesopores of a regular structure. The physical properties such as surface area, pore size, pore structure, particle size, and morphology were studied by BET, SEM, SAXS, and DLS analysis. At a fixed gas flow rate, the BET surface area changed from 200 to $1,290m^2/g$ as changing the CTAB/TEOS molar ratio from 0.05 to 0.3. At a fixed CTAB/TEOS ratio, the surface area of silica particles was varied from 1,062 to $1,305m^2/g$ with changing the gas flow rate from 10 to 40 l/min. The average pore size measured by BJH desorption was about $21{\sim}23{\AA}$ and not significantly influenced by the CTAB/TEOS ratio and the gas flow rate. Finally, the highest surface area which was $1,305m^2/g$ were obtained when the CTAB/TEOS ratio and the gas flow rate were 0.2 and 20 l/min, respectively. According to SAXS analysis, the prepared silica particles showed a strong peak at $2{\theta}=2.6^{\circ}$ and two minor peaks around $2{\theta}=4.4^{\circ}$ and $5.1^{\circ}$, which are due to regular mesopores of hexagonal structure. The morphology of silica particles prepared were spherical shape and the average particle size was $1.0{\mu}m$.

• Resources Recycling
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• v.25 no.6
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• pp.41-49
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• 2016

The present study was intended to prepare cobalt oxide ($Co_3O_4$) powder of average particle size 50 nm or less by spray pyrolysis reaction using the raw cobalt chloride ($CoCl_2$) solution, in order to identify the change in the nature of the particles according to the change in the nozzle tip size. When the nozzle tip was 1 mm, it turned out that most of the droplets were spherical and the surface showed very tight structure. The average particle size of the finally formed particles was 20-30 nm. When the nozzle tip size was 2 mm, some of the droplets formed were spherical, but a considerable part of them showed severely disrupted form. particles formed showed an average particle size of 30 - 40 nm. For the nozzle tip size of 5 mm, spherical droplets were almost non-existent and most were in badly fragmented state. The tightness of surface structure of the droplets has greatly been reduced compared with other nozzle tip sizes. Average size of the formed particles was about 25 nm. As the nozzle tip size increased from 1 mm to 2 mm and 3 mm, the intensities of the XRD peaks have changed little, but significantly been reduced when the nozzle tip size increased to 5mm. As the nozzle tip size increased from 1 mm to 2 mm, the specific surface area of the particles decreased, but the nozzle tip size increased to 5mm, the specific surface area remarkably increased.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2007.05a
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• pp.61-64
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• 2007

Fe-PC와 Fe-TCPC를 합성하여 암모니아 탈착에 따른 촉매의 특성과 황화합물 및 아민류의 흡착실험을 수행하여 다음과 같은 결론을 얻었다. 1) FT-IR로 분석한 결과, Fe-TCPC는 Fe-PC에 비해 카르복실기의 특성 스펙트럼이 관찰되었고, SEM/EDS로 관찰한 결과 카르복실기의 영향으로 Fe의 비율이 낮고 산소의 량은 높게 나타났으므로 표면에 카르복실기가 존재하고 있음을 알 수 있었다. 2) TPD 실험에서 철 프탈로시아닌 유도체는 두 개의 피크가 저온부와 고온부에서 나타나 약산점과 강산점이 존재하고 있음을 확인 할 수 있었으며, 탈착량은 Fe-TCPC가 Fe-PC보다 고온부에서 강산량점량이 많았고 저온부에서 약산점량은 적게 나타난 것으로 보아 Fe-TCPC가 표면에 카르복실기의 화학적흡착 영향으로 강산점에서 많은 탈착이 일어났음을 의미한다. 3) Fe-TCPC는 Fe-PC보다 비표면적과 세공부피가 많았고, 과산화수소의 분해효율이 높아 촉매적 성질이 우수하였으며, 또한 입자의 크기도 작았음을 확인하였다. 이는 모든 조건에서 Fe-TCPC가 Fe-PC보다 흡착능력이 우수한 것으로 예측된다. 4)카르복실기가 치환된 철 프탈로시아닌 유도체의 제거효율은 아민화합물이 우수하지만 황화합물에서 다소 낮게 나타났다. 이 결과로 보아 아민류에 효과가 있는 카르복실 철 프탈로시아닌을 착색제로 사용하면 탈취 기능을 가진 안료가 될 것으로 생각된다.

• Food Science and Preservation
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• v.18 no.2
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• pp.199-207
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• 2011

Physico-chemical characteristics such as width, weight, color and aroma compounds of garlic from 9 different areas were analyzed. Also, antimicrobial activity was tested for their juices. Width of garlic bulb was larger in growing worm-season garlics (Jeju, Namhae, Hapcheon, Hampyeong and Muan) than those of cool-season garlics (Taean, Seosan, Uiseoung) and imported from China. But numbers of nuts were smaller in growing cool-season garlics than others. L color levels of garlics were 80.73~87.40 and a color level have not significantly difference in all samples, b color level was lower in growing Namhae ($20.79{\pm}1.20$) and Muan ($20.91{\pm}1.62$). 25~30 peaks obtained from aroma compounds analysis of various garlics. Among these compounds, 17 kinds of aroma compounds were identified by GC-MS. And, we showed that 15 kinds of compounds were sulfur containing aroma compounds. Diallyl disulfide was contained 34.90~60.54% in various garlic and the highest contents than other compounds in total compounds. It was detected the highest in China garlic but the lowest in growing Muan garlic. All of garlic samples showed antimicrobial activity against Strep. mutans, B. subtilis, E. coli. V. parahaemolyticus, Asp. flavus, and C. albicans. Especially antimicrobial activity was stronger against E. coli, and C. albicans. Antimicrobial activity was enhanced by sample addition volume and the highest in Namhae garlic sample.

• Applied Chemistry for Engineering
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• v.29 no.1
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• pp.122-126
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• 2018

Mesoporous molecular sieves were prepared by the reaction of $Na_2SiO_3$ and $H_2SiF_6$ using nonionic micelle templates in an aqueous solution. Well-crystalline mesoporous molecular sieves were obtained after several seconds at atmospheric conditions. Powder samples exhibited d-spacing of 3.8-5.1 nm with the sharpness of the d00l peak, showing well-crystalline mesoporous molecular sieves, pore size distributions of 2.5-3.1 nm and large specific surface areas of $290-1,018m^2/g$, depending on types of surfactants. SEM images of samples showed well-divided spherical particles with an uniform size of ${\sim}0.5{\mu}m$ and TEM images demonstrated uniform pores with a worm hole shape.

• Korean Journal of Food Science and Technology
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• v.26 no.2
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• pp.162-166
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• 1994

A rapid gas chromatographic (GC) profiling method for the simultaneous analysis of volatile and nonvolatile organic acids was applied to alcoholic beverages (white wine, red wine, brandy, and beer). It involves the solid-phase extraction of organic acids using Chromosorb P as the sorbent and diethyl ether as the eluent with subsequent triethylamine treatment. The resulting triethylammonium salts of acids were directly converted to volatile tert.-butyldimethylsilyl derivatives, which were analyzed by dual-capillary column GC and GC-mass spectrometry. From the alcoholic beverages studied, more than 29 organic acids were detected. When the simplified retention infer (RI) spectra of organic acids, and the direct comparisor method between alcoholic beverages and a test sample were attempted to identify a test sample, it was quickly recognized to be a red wine with the 998 ppt match quality value.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.291-299
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• 2004

DLC films were deposited using the ECR-PECVD method with the fixed deposition condition, such as ECR power, methane and hydrogen gas-flow rates and deposition time, for various substrate bias voltage. We have investigated the ion bombardment effect induced by the substrate bias voltage on films during the deposition of film. The characteristic of the films were analyzed using the FTIR, Raman, and UV/Vis spectroscopy analysis shows that the amount of dehydrogenation in films was increased with the increase of substrate bias voltage and films thickness was decreased. Raman scattering analysis shows that integrated intensity ratio(ID/IG) of the D and G peak was increased as the substrate bias voltage increased and films hardness was increased. Optical transmittances of DLC film were decreased with increasing deposition time and substrate bias voltage. From these results, it can be concluded that films deposited at this experimental have the enhanced characteristics of DLC because of the ion bombardment effect on films during the deposition of film.

• Korean Journal of Optics and Photonics
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• v.33 no.3
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• pp.106-112
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• 2022

A two-dimensional optical code division multiple access (OCDMA) encoder/decoder, which is composed of add/drop filters and all-pass filters for delay operation, is proposed. An example design is presented, and its feasibility is illustrated through numerical simulations. The chip area of the proposed OCDMA encoder/decoder could be about one-third that of a previous OCDMA device employing delay waveguides. Its performance is numerically investigated using the transfer-matrix method combined with the fast Fourier transform. The autocorrelation peak level over the maximum cross-correlation level for incorrect wavelength hopping and spectral phase code combinations is greater than 3 at the center of the correctly decoded pulse, which assures a bit error rate lower than 10^-3, corresponding to the forward error-correction limit.

• Journal of Food Hygiene and Safety
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• v.22 no.4
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• pp.243-247
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• 2007

A selective analytical method of headspace-GC/MS has been applied to determine levels of benzene in beverages. Food samples were 85 including 2 fruit juices, 6 fruit beverages, 11 carbonated beverages, 55 mixed beverages, and 4 beverage concentrations, and 7 extracted beverages. For phase equilibration of headspace, sample was stirred at $40^{\circ}C$ for 30 min. The oven temperature was $60^{\circ}C$ and elevated to $180^{\circ}C$ at $15^{\circ}C/min$. The internal standard was benzene-d6. The identification was done by the selected target ions such as m/z 51, 77, and 78 and the confirmation was done by the response ratio of m/z 77 to m/z 78 between sample and standard. The overall recoveries were ranged from 91% to 101% and the limit of quantification was $1{\mu}g/kg$. The average level of benzene were $5{\mu}g/kg$ for fruit beverages, $2{\mu}g/kg$ for carbonated beverages, $7{\mu}g/kg$ for mixed beverages and $7{\mu}g/kg$ for extracted beverages.