• 동아시아식생활학회지
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• 제3권2호
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• pp.99-106
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• 1993

The aim of this study is to elevate the efficiency of salting with low salt concentration in order to improve the quality of salted Chinese cabbage. The efficiency of salting was tested with various sub-atmosphere(760mmHg to 0mmHg), temperature(20$^{\circ}C$ and 30$^{\circ}C$), and concentration of salt(3%, 5% and 10%). The salting efficiency was estimated by amounts of juice, calcium elution, sodium penetration and the state of tissue. The amunts of juice eleuted from Chinese cabbage was increased significantly with the decrease of atmosphere and the time to reach the highest amounts was reduced. This tendency was promoted, with increase of salinigy(from 3% to 10%)and the increase of temperature(more juice at 30$^{\circ}C$ than 20$^{\circ}C$). The amounts of eluted calcium from Chinese cabbage tissue during salting under sub-atmosphere was directly proportional to amounts of juice and was inversely proportional to penetrated sodium. The salting time was reduced with elevation of sub-atmosphere. It was desirable to take between 5.5 and 9 hours to salt under the condition of 3% of salting, 20$^{\circ}C$, and 560-0mmHg. It took between 4.4 and 5 hours under 5% of salt and between 4 and 4.5 hours under 10% of salt. However, it was undesirable because the drying phenomenon and the transparency of tissue appeared under 30$^{\circ}C$ and 160-0mmHg.

• 한국식품과학회지
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• 제13권1호
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• pp.25-29
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• 1981

생아스파라가스의 저장기간을 연장하기 위하여, 아스파라가스(Viking variety)를 정상대기 저장과 C.A. 저장을 하였다. 이때, 밑부분을 물에 담근것과 물에 담그지 않은 것으로 나누어 처리하였다. CA저장은 아스파라가스의 경우 박테리아에 의한 무름병이 발생하는 것을 현저하게 감소시켰으며, 밑부분을 물에 담그어 CA저장을 한결과 무름병 없이 3주일이나 저장할 수 있었다. 섬유질의 분석과 인스트론(Instron)을 이용하여 저장한 아스파라가스의 조직변화를 관찰하였는바, 저장기간이 늘어남에 따라 차츰 질겨지는 것을 볼 수 있었다. 아스파라가스의 섬유질함량은 CA저장에 의하여 그 증가폭이 훨씬 둔화되었고, 밑 부분을 담그어 CA저장을 한 경우 섬유질이 양은 줄어드는 것으로 나타났다. CA 저장에 의한 경우 정상 대기 저장에 비하여 아스파라가스 중의 엽록소 파괴는 훨씬 적게 나타났으며, Reflectance color value와 엽록소 양과는 서로 유의성 있는 상관관계를 나타내고 있다. 저장한 아스파라가스의 품질을 변화시키는 여러 가지 요인을 고려할 때 밑부분을 물에 담그어 CA저장을 하는 것이 아스파라가스의 품질을 3주일 이상 유지시켜 주는 가장 좋은 방법이라 할 수 있겠다.

• 한국결정성장학회지
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• 제19권6호
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• pp.318-323
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• 2009

본 실험에서는 로터리 킬른으로 제조되는 인공경량골재의 실험실적 제어 가능성을 찾고자 여러 가지 소성조건에서 석탄 화력발전소에서 발생되는 바닥재와 준설토를 이용하여 인공경량골재를 제조하였다. 인공경량골재 조성은 바닥재 70 wt%와 준설토 30 wt%의 무게비로 성형하였고, 산화 분위기, 불활성 분위기, 환원 분위기에서 각각 $1150^{\circ}C$, $1200^{\circ}C$에서 소성하여 제조된 인공경량골재는 산화 분위기에서 명확한 블랙코어와 껍질(shell)간의 경계를 보이나, 불활성 분위기에서는 질소량이 증가할수록 그리고 소성온도가 증가할수록 경계가 없어지는 경향을 보이며, 환원 분위기에서는 단면 전체가 진회색을 띄게 된다. 로터리 킬른의 분위기와 가장 근접한 소성 분위기는 불활성분위기였으며 밀도나 흡수율 또한 그것과 유사하였다. 이러한 결과로 소형 전기로에서 로터리 킬른의 환경과 유사하게 조건을 제어할 수 있고, 물성을 예측할 수 있는 실험이 가능할 것으로 생각된다.

• Journal of Ginseng Research
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• 제22권2호
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• pp.73-81
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• 1998

In order to stabilize the price of fresh ginseng by extension of seasonal variation and marketing structure, and to reduce the cost of production by works of intensive and short term, studies were carried out. As fresh ginseng of 4 years old by the MA (modified atmosphere storage) and CA (controlled atmosphere storage) was stored for 12 week at 4$^{\circ}C$, samples were collected after every 1, 2, 3, 4, 6, 8, 12 weeks for processing red ginseng. Chemical characteristics on ginseng steamed red for the quality evaluation are summarized as follows. The composition of free sugar was consisted of fructose, glucose, sucrose, and maltose in fresh ginseng. And small change was revealed in free sugar composition during the storage period. Glucose and sucrose were largely increased in both treatments of MA (modified atmosphere storage) and CA (controlled atmosphere storage) after 4 week, wherein maltose was decreased. Fifteen different amino acids were identified, and total amount of histamine and arginine were over 40%. Phenylalanine was slightly decreased. As the volatile components in control red ginseng, six different ones including triisopropyl benzene were detected. B-1 ($CO_2$ : $O_2$ : N2=6 : 4.90, DF-100) of CA and E-1 (CPP, DF-100) of MA did not shown triisopropyl benzene as the volatile components. And ${\gamma}$-muurolene, guaiaene, and beta-patchoulene were reduced, but the other components showed the trend of increase.

• 한국전기전자재료학회논문지
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• 제26권1호
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• pp.22-26
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• 2013

PTCR ceramics of $(Ba_{0.998}Sm_{0.002})TiO_3+0.001MnCO_3+xSiO_2$ (x=1, 2, 3, 4, 5, 6 mol%) were fabricated by solid state method. Disk samples of diameter 5 mm and thickness about 1mm were sintered at $1,290^{\circ}C$ for 2 h in reduced atmosphere of $5%H_2-95%N_2$ followed by re-oxidation at $600^{\circ}C$ for 30 min. in $20%O_2-80%N_2$.and their microstructures and electrical properties were investigated with SEM and Multimeter. The color of sintered samples was strongly dependent on $SiO_2$ content showing that the color of samples with $SiO_2$ of 1~2 mol% was gray but that of samples with $SiO_2$ of 4~6 mol% was changed from gray to blue, which seems to be related with the reduction of samples due to the oxygen vacancies created during the sintering in reduced atmosphere. $SiO_2$ content had a great influence on the microstructure and the electrical properties. With increasing $SiO_2$ content, the grain size of samples increased and the resistivity as well as the resistivity jump ($R_{285}/R_{min}$) decreased, which is considered to be attributed to the resistivity change at grain interior and grain boundary due to the fast mass transfer through $SiO_2$ liquide phase during the sintering. Samples with 2 mol% $SiO_2$ has the resistivity of $202{\Omega}cm$ and the resistivity jump of 3.28. It is expected that $SiO_2$ doped $BaTiO_3$ based PTC ceramics can be used for multilayered PTC thermistor due to the resistance to the sintering in reduced atmosphere.

• Journal of Advanced Marine Engineering and Technology
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• 제26권6호
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• pp.661-669
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• 2002

Rapid tooling technique enables us to make dies and molds that produce prototype parts with the correct material at a substantially reduced cost and time. In this study, experiments on selective laser sintering of tungsten carbide-cobalt mixture were carried out to find optimal sintering conditions that will be applied to rapid metal tooling. The experiments were carried out within an air, an argon and a nitrogen atmosphere. Coupons of single layer were sintered at various laser powers, scanning speeds and scan spacings. Very severe oxidation took place within an air atmosphere. The oxidation is reduced significantly within an argon and a nitrogen atmosphere. The thickness of the sintered coupons is increased as the energy density, the laser energy Per unit scanned area, is increased. Several multi-layer sintering experiments were also carried out.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 추계학술대회 논문집
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• pp.269-274
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• 2001

This paper describes the experimental results on direct selective laser sintering of WC-Co mixture. The experiments were carried out within an air, argon and nitrogen atmosphere. The main problem occurred during sintering within an air atmosphere was oxidation of WC-Co mixture. As the power of laser is increased and scanning speed is decreased, more severe oxidation takes place. Within an argon and nitrogen atmosphere the oxidation is reduced significantly. As the energy density is increased the thickness of the sintered layer is increased.

• 한국세라믹학회지
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• 제51권1호
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• pp.25-31
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• 2014

New green phosphor is synthesized by reducing $LiAlO_2:xEu^{3+}$ phosphors in a low pressure $H_2$ atmosphere. The $LiAlO_2:xEu^{3+}$ prepared by a solid state reaction method is reported as red phosphor. The effect of the reduction treatment on the $LiAlO_2:xEu^{3+}$ on the crystalline phase change and photoluminescence (PL) property are characterized. The reduced phosphor had a broad green light spectrum centered at 524 nm. The PL intensity of the reduced phosphor increased to a maximum at the reduction temperature of $1100^{\circ}C$. The PL intensity decreased with a further increase in the reduction temperature. The crystalline phase constituting the reduced phosphor varied with the temperature. A new crystalline phase $Li_2Al_4O_7$ was observed at $1100^{\circ}C$. The origin of the green-light emission is discussed in relation to the crystalline phase change.

• 한국지구과학회:학술대회논문집
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• 한국지구과학회 2005년도 춘계학술발표회 논문집
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• pp.115-125
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• 2005

Carbon isotopic composition of a stream (Odaecheon Stream) monitored over 7 months from July 2004 to January 2005 in Gangweon Province ranges from -9.24 to -4.69‰. Strong negative correlation between ${\delta}^{13}C_{DIC}$ and water temperature suggests that temperature is a dominant factor controlling ${\delta}^{13}C_{DIC}$ in the Odaecheon Stream. The variation pattern of ${\delta}^{13}C_{DIC}$ was thought to be caused by fractionation of C isotope between stream water and atmosphere and more fractionation at reduced temperature. More fractionation of C isotope between stream water and atmosphere at reduced temperature resulted in increase of ${\delta}^{13}C_{DIC}$ of stream water in winter compared to summer. Photosynthesis and respiration of aqueous biota seem to affect little in ${\delta}^{13}C_{DIC}$ as indicated by little variation of dissolved oxygen and reverse variation pattern of Eh in the stream and scarce aqueous biota in stream water. pH seems to be controlled by $CO_2{2}$ exchange between stream water and atmosphere. During summer more $CO_2{2}$ exchange between stream water and atmosphere resulted in decrease in pH value.

• 한국세라믹학회지
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• 제26권3호
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• pp.381-389
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• 1989

Effects of annealing temperature, time, and atmospehre on the flow characteristics of Atmospheric Pressure Chemical Vapor Deposition-borophosphosilicate glass were investigated. Stable step coverage can be obtained by annealing the BPSG film at 90$0^{\circ}C$ for 30 minutes in N2 atmosphere, but further heat treatment isnot effective. Flow characteristics of the BPSG film was better in steam atmosphere than in N2 atmosphere, and the factors which cause it were analyzed. The concentration of boron in the BPSG film was measured pretty accurately by FTIR spectrum. Boron content in the BPSG film was reduced by annealing treatment. The decrement of boron was greater in steam atmosphere than in the N2 atmosphere. Also it was found from the FTIR spectroscopic analysis that PH3 inhibited the oxidation of B2H6.