• Applied Biological Chemistry
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• v.27 no.2
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• pp.86-94
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• 1984

The changes of the volatiles from apple fruits were examined with Mallus pumila Miller var. Fuji, Ralls Janet and Jonathan harvested at the preclimacteric stage and stored under the normal atmospheric pressure of 760mmHg and subatmospheric pressure of 380mmHg at the temperature of 1 and $20^{\circ}C$ each. The production of the volatites in the normal storage temperature increased markedly up to around 30 days on storage and then decreased rapidly, whereas that of the volatiles in the low storage temperature increased slowly before decreasing. The changing pattern of volatiles from apples during storage at the normal atmospheric pressure was more remarkable than that of volatiles produced at the subatmospheric pressure. During storage, most of flavoring materials were increased, and the decrease of the content of esters was more rapid than that of alcohols and aldehydes among the volatiles. The amounts of the volatiles in Fuji apples during ripening at $20^{\circ}C$ after removing from the subatmospheric pressure storage for 90 days at $1^{\circ}C$ were nearly maximum at 3 days on ripening.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.369-376
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• 2017

Maturation of distilled spirit can generate diverse flavors and tastes. Rice Soju was matured in oak casks (MSO) and stainless steel containers (MSS) for one year at ambient temperature. Ipguk (Aspergillus luchuensis) and Saccharomyces cerevisiae Y88-4 were used, and reduced pressure ($110{\pm}20Torr$) distillation was applied to brew Soju. Acidity and conductivity were increased in both MSO and MSS. MSO reduced alcohol content (from 43 to 40%) and volume (from 18,000 to 12,730 mL), and significantly altered yellowness (from 0.2 to 30.2). Furthermore, MSO increased the isoamyl alcohol (from 276.7 to $339.2{\mu}g/mL$) and isobutyl alcohol (from 122.3 to $144.2{\mu}g/mL$) content. Gas chromatography-mass spectrometry was used to detect volatile compounds in Soju, which included 20 esters, 7 alcohols, 2 acids, and 5 miscellaneous compounds. Oak lactone was detected only in MSO and was considered as a specific flavor component associated with oak maturation. Thus, maturation materials contribute to the physicochemical property of distilled spirits.

• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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• pp.153-156
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• 2004

광 전송 마이크로 셀룰라 시스템과 부반송파 다중 송신 시스템 같은 마이크로파 광 전송기술을 이용한 시스템들은 송신기의 비선형성에 의해서 발생하는 많은 왜곡 성분들, 특히 레이저 다이오드에서 발생한 왜곡 성분들에 의해서 많은 성능의 제한을 받는다. 이러한 왜곡 성분들을 제거하기 위해서 광 피드포워드 방식을 이용한 광 송신기를 제안하였다. 제작된 피드포워드 선형화 아날로그 광 송신기는 2.1 GHz 투톤 실험에서 38 dB의 IMD 개선 효과를 보였다. 여기에서 위상 천이기와 전압 가변 감쇄기는 신호 크기 허용오차를 0.1 dB, 위상 허용오차 $1^{\circ}$범위 이내에서 설계하였다. 이를 위해서 세밀한 위상과 크기의 조정이 가능한 위상 천이기와 전압 가변 감쇄기를 제작하였고, 측정한 결과, 전압 가변에 따른 위상 변화량과 크기 변화량은 각각 위상 천이기는 $90^{\circ}$, 전압 가변 감쇄기는 14 dB를 기록하였다.

• Journal of Food Hygiene and Safety
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• v.6 no.1
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• pp.49-56
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• 1991

Physico-chemical properties were investigated on ginseng leaf tea which was decontaminated by the current ethylene oxide fumigation and gamma irradiation, respectively. Chemical components such as soluble matter, saponin and polyphenols were found to be stable to both treatments, while ascorbic acid and chlorophylls were relatively labile to fumigation and irradiation more than 5 kGy. Instrumental analysis has shown that EO fumigation causes apparent changes in pH and color of extracts and volatile profile of the sample, as compared to negligible changes in the irradiated sample at a decontaminating dose, 5 kGy.

• Food Science and Preservation
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• v.8 no.4
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• pp.442-448
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• 2001

The citrus juice obtained from Jeju mandarines, Citru unshiu, was filtered to remove 20% of its original volume through the hollow fiber ultrafiltration systems equipped with various pore sizes of membranes. As the results of ultrafiltration, the contents of total acids, ascorbic acid, ascorbic acid, free sugars and neohesperidin in retentate showed the tendencies of gradual decreases with the increase of membrane pore sizes from 10K to 100K daltons, but tendencies were inverted when the membrane with 500k was used. The changes of color, soluble solids, total nitrogen, amino-nitrogen, naringin and hesperidin were not consistent with the membrane pore size. Considering all the data obtained using various pen sizes of membranes, the filtration system with NMWC 500K daltons was the most effective to produce citrus juices with hither quality.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2003.07a
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• pp.83-83
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• 2003

우리 전통주의 질적인 향상과 저장성이 우수한 무증자 발효주를 제조하기 위하여 쌀과 옥분의 배합 비율을 쌀 100%, 쌀 80%＋옥분 20%, 쌀 60%＋옥분 40%, 쌀 40%＋옥분60%, 쌀 20%＋옥분 80%로 달리하여 무증자로 담금한 발효주와 쌀 100%로 증자하여 발효시킨 주류의 물리화학적인 변화 및 성분함량을 측정하였으며 관능검사를 병행하여 비교 검토하여 다음과 같은 결론을 얻었다. 1) 술덧의 온도변화는 발효 초기 30 에서 시간의 경과에 따라 서서히 감소하여 발효중기 27.5 를 거쳐 발효 종료 시 모두 26.5 였다. 2) 술덧의 주정도 변화는 옥분의 양을 첨가할수록 낮아지는 경향을 보였으며 16∼18.3v/v% 였다. 3) 유기산은 무증자주는 쌀 100%일 때 0.6 g/dl로 증자주 0.49g/dl보다 높았으며 옥분을 첨가한 무증자주에서는 옥분이 첨가될수록 차즘 감소하여 80%일 때 0.34 g/dl 였다. 4) 유리아미노산 함량은 옥분이 40% 첨가되면서부터 leucine의 함량이 쌀 100% 증자주에 비해 2배 이상 증가하였으며 leucine>arginine>lysine의 순이었다. 5) 유리당 함량은 무증자로 옥분을 첨가할수록 증가하여 옥분 80%에서는 9.81mg/dl였다. 6) 휴젤유는 278.6ppm∼441.6ppm으로 쌀100% 무증자에 비해 옥분이 첨가될수록 감소하여 옥분 80%일때 가장 적은 278.6ppm이었다. 7) 휘발성 향기성분중 ester함량은 100% 무증자주에서 총 9종류가 검출되었으나 옥분이 첨가되면서 10∼12 종으로 많아졌다. Ethyl octanoate는 옥분 60%첨가 무증자주에서 19.26%로 많이 나타났으며 ethyl acetate는 옥분이 첨가되면서 증가하였다. 특히 옥분 80% 무증자주는 총 ester류함량은 적었으나 isoamyl acetate, phenylethyl acetate, ethyl octanoate, ethyl acetate의 함량이 비교적 많이 검출되어 독특한 향기를 기대할 수 있었다. 8) GC/O를 사용하여 향기성분을 동정한 결과 무증자 발효주 시험구에서는 옥분을 첨가할수록 sweet 및 warm note가 강하게 나타나는 현상을 보였다. 9) 발효주의 색도를 측정한 결과 밝기에서는 무증자구가, 적색도에서는 옥분 첨가량이 증가할수록 강하였으며 황색은 증자주보다는 무증자주의 옥분 첨가량의 증가에 따라 높아지는 경향을 보였다. 10) 관능검사 결과 쓴맛, 미묘한 맛, 좋은 맛, 떫은 맛, 신맛 그리고 좋은 맛에 대한 전체 적인 평가를 종합하면 쌀 100% 증자발효주가 가장 점수가 낮아 무증자 발효주에 비하여 기호도가 떨어지는 것으로 나타났으며 특히 옥분 첨가량 80%와 60%의 무증자주가 기호도 면에서 유의적으로 가장 높게 평가되었다.

• Journal of Astronomy and Space Sciences
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• v.19 no.1
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• pp.75-88
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• 2002

The climatological characteristics of the polar ionosphere is examined in terms of the ionospheric conductance and electric field. For this purpose, 109 days of measurements from the Sondrestrom incoherent scatter radar are utilized. By combining these two quantities, it is possible to deduce the overhead ionospheric current distributions. The ionospheric current density thus obtained is compared with the corresponding ground magnetic disturbance. Also examined is the effect of the field-aligned current on the ground magnetic disturbance, particularly on the D component Several interesting climatological characteristics about the ionosphere over the Sonderstrom are apparent from this study. (1) The conductance distribution is mainly due to solar EUV radiation during day-time On the other hand, the conductance distribution during the night-time is very low. (2) The conductance distribution one. the polar cap region during the day-time is controlled mostly by the solar EUV radiation, while it is extremely low during night-time wish the Hall and Pedersen conductances being 1.6 and 1.2 siemen, respectively (3) The region of the maximum N-S electric field tend to locate in the dayside sector. The E-W component of the electric field is stronger than that over Chatanika (4) The E-W auroal inospheric current (J/sub E/) is more important in the sunlit hemisphere than the night hemisphere. And a strong southward current is noted in the prenoon sector (5) There is a significant correlation between the overhead ionospheric current and the simultaneously observed ground magnetic disturbance. However, the assumption for the infinite sheet current approximation is far from realistic, underestimating the current density. And the correlation between ${\Delta}H$ and J/sub E/ is higher than the one between ${\Delta}D$ and J/sub N/ , indicating that field-aligned current affects significantly ${\Delta}D$.

• Journal of Korea Foresty Energy
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• v.24 no.2
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• pp.1-9
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• 2005

After manufacturing fermentation system for degrading pig manure using environmentally friendly technique, performance of the system and characteristics of wood chips and pig manure fermented in the system were analyzed. Results from this study shows that proper fermentation temperature($55{\sim}60^{\circ}C$) reached 3days after the system started and degradation rate, which expresses fermentation performance of system, was $180{\iota}$/day. Even as progressing the fermentation of wood chips and pig manure mixture, the amount of extractives drawn out by alkali, and alcohol-benzene and lignin content was not varied. However, ash content in wood was increased. The inorganic compounds in pig manure seem to be transferred into wood chip. On the other hand holocellulose contents in wood were decreased a little. Holocellulose seems to be consumed as the second carbon source in fermentation process. Results through analysis of inorganic- and heavy metal elements contents in wood chips and pig manure fermented in long term process shows that inorganic elements($Ca^{2+},\;Mg^{2+},\;K^+,\;Na^+$ etc.) contents were increased with fermentation time and heavy metal elements(Cd, As, Cu etc.) which cause environmental pollution were not detected. Number of microorganisms including bacteria, actinomycetes, and fungi, the number of C.F.U(Colony Forming Unit) was increased while temperature in fermentation system was abruptly increased.

• Journal of the Korea Concrete Institute
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• v.20 no.6
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• pp.797-807
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• 2008

For this study, the semi-adiabatic temperature rising test is accomplished by using ternary system cement (OPC, BFS, FA) reducing temperature crack. Two tests are conducted; one is for the paste test, and the other is for the concrete test. As the results of paste tests, using fly ash is better to reduce hydration temperature than doing blast furnace slag. In the case of the paste mixed ternary system cement, the more fly ash is mixed and the less blast furnace slag is used, the lower the temperature is. The less the mixture ratio of blast furnace slag is and the more the mixture ratio of fly ash is, the later the temperature rising velocity and descending velocity are. Besides, the temperature is lower if water/binder ratio is high. The use of ternary system cement has the retardation effect of temperature rising because the time to reach the maximum temperature is in the order of OPC100, binary system cement, and ternary system cement. From the test, the maximum temperature of concrete used ternary system cement is $8{\sim}11^{\circ}C$ lower than that of concrete used OPC100. Moreover, temperatures rising velocity and descending velocity of ternary system cement range $47{\sim}51%$ and $37{\sim}42%$ compared with OPC100. The specimen of concrete shows remarkable low internal temperature and slow temperature rising velocity and descending velocity compared with the specimen of paste because it is that temperature loss of concrete is much more than paste specimen according to aggregates.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.5
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• pp.33-39
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• 2008

We have experimentally demonstrated the transmission performance of a feedforward optical transmitter using an external light injection technique. The feedforward compensation method shows 31 dB intermodulation distortion suppression and 2.2 dB noise reduction. A high side-mode suppression ratio exceeding 35 dB of the wavelength of the locked Fabry-Perot laser diode was obtained over 12 nm ranges. The suppression characteristics of the intermodulation distortion for various wavelength differences and transmission lengths were measured and analyzed as the evaluation criteria for the system performance in WDM/SCM based radio-over-fiber systems.