• 한국식품영양과학회지
• /
• 제40권2호
• /
• pp.229-234
• /
• 2011

본 연구에서는 4년근 인삼의 활용도를 높이기 위하여 효소적 가수분해 조건에 따른 품질 특성을 조사하였다. 인삼은 증숙 후 분쇄하여 가수분해 효소제 A, B, C 및 D 4종에 처리에 따른 품질특성을 조사한 결과 pH 5.5~5.6, 당도 4.0~4.33으로 큰 차이가 없었다. 조사포닌 함량은 D 효소제에서 가장 높았으며, B, C 및 A 순으로 나타났다. D 효소제의 농도 0.3%(w/w)까지 조사포닌, 환원당 및 총당 함량이 증가하였으며 이후에는 농도에 따른 차이는 없었다. 가수분해시간이 경과함에 따라 유효성분이 증가하였으나 3시간 이후 큰 변화는 없었으며, $60^{\circ}C$로 처리하였을 때 조사포닌 함량이 높게 나타났다. 이상의 실험결과 D 효소제, 효소제 농도 0.3% (w/w)로 $60^{\circ}C$에서 3시간의 조건이 가장 적합한 나타났으며 이때 환원당, 총당 및 조사포닌 함량은 각각 18.11, 36.21 및 4.23 mg/g으로 확인되었다. 따라서 효소적 가수분해 방법은 4년근 인삼의 유효성분 증가에 효과적으로 다양한 활용 방법이 기대되었다.

• 전기화학회지
• /
• 제2권3호
• /
• pp.123-129
• /
• 1999

리튬이온전지용 $LiCoO_2$ 전극의 super s black 도전재료의 함량에 따른 초기 충방전 특성을 1 mol/l $LiPF_6/EC+DEC(1:3\;by\;w/w)$의 전해액에서 리튬기준전극에 대하여 4.3 V에서 2.0 V의 전위 구간에 대하여 C/4 및 C/2율로 충방전하여 측정하였다. 최초의 충전과정에서 high impedance충전 특성을 보였으며, super s black도전재료를 $3\%w/w$ 사용한 경우, $0.5 mA/cm^2$ 전류밀도의 충전에서 high impedance의 해소에 따라 $3.82\;{\Omega}\;{\cdot}\;g-LiCoCo_2$의 저항 감소를 나타내었으며, $0.728\;{\Omega}{\cdot}g-LiCoCo_2$의 전극저항과 비교하여 약 7배 높은 값을 나타내었다. 제2차 충전에의 high impedance해소는 약 $63\;{\Omega}{\cdot}g-LiCoCo_2$으로서 전극저항의 $12\%$ 정도이며, 제1차 충전의 high impedance해소에 비하여 $1.7\%$의 수준으로 감소하였다. 제1차 충전 및 방전 비용량은 C/4방전율에서 각각 160-161 및 $153\~155mAh/g-LiCoO_2$으로, 쿨롱효율은 $95.4\~96.4\%$였으며, 비가역 비용량은 약 6 mAh/g-$LiCoO_2$였다. 충전종료 지점에서 측정한 비저항은 도전재료 함량 $2\~7\%w/w$범위에서 낮은 값을 나타내어 비가역 비용량 특성의 변화와 일치하였다. 도전재료의 함량 증가에 따라 용량밀도가 감소하였으며, C/4율 방전에서 super s black함량 $2\%w/w$와 $2.9\%w/w$의 도전재료를 사용한 전극의 용량밀도는 각각 447mAh/ml 및 431 mAh/ml였다

• 한국의류학회지
• /
• 제21권3호
• /
• pp.536-543
• /
• 1997

The subjects wearing cool clothing (C group) or warm clothing (W stoup) in daily life from September to February of the following year were tested to examine whether cold acclimatization takes place by clothing habits. Subjects rested at 25$\pm$1$^{\circ}C$, then were exposed to 15$\pm$1$^{\circ}C$, 50$\pm$5% R.H. for 90 min in September, November, December, and February. Rectal temperature (Tre) of C group after 90 min cold exposure did not drop below the Tre in $25^{\circ}C$ throughout the study. W group's Tre, however, dropped below the temperature in 25t from December. Shivering stopped after December in C group while W group continued to show it for the whole study. In resting, C group showed higher heat production than W group in February, and the rate of increase in heat production during cold exposure was smaller in C group than W group in February. C group showed less cold sensation than W group in the same coldness. These results suggest that the level of cold acclimatization may be improved by the habits wearing less clothes in daily life.

• 동력기계공학회지
• /
• 제10권3호
• /
• pp.51-57
• /
• 2006

The effect of grain size on corrosion resistance and high temperature oxidation behavior was studied in 22Cr-15Ni-5W super austenitic stainless steels for desulfurization equipment as a heat power station. In the high temperature oxidation test, oxidation rate was increased as the temperature increased from $600^{\circ}C\;to\;800^{\circ}C$. In vapor, oxidation rate was faster than that in air. Because the vapor was inhibited nucleation of $Cr_2O_3$ film. And the high temperature oxidation resistance at $600^{\circ}C{\sim}800^{\circ}C$ was excellent from all specimens and specimen of the smallest grain size was the most excellent. Because increasing of diffusion course through the grain-boundary was promoted nucleation and growth of $Cr_2O_3$ film. In the test temperature at $600^{\circ}C{\sim}800^{\circ}C$, Cr rich round particle oxide was formed in air, whereas Fe rich needle type oxide was developed in vapor.

• 조명전기설비학회논문지
• /
• 제14권3호
• /
• pp.38-42
• /
• 2000

플라즈마 중합박막은 내정전 플라즈마 중합장치에 의해서 제조되었다. 중칙률을 4O[W]에서 100[W] 사이에서 최대값을 나타내었다. ESCA 분석에샤는 285.4와 285.5[eV]에서 -CH2, -C-를 나타내는 피크들을 보였다. 무시할 수 없는 양으로 산소와 그룹화 되어 있는 532.8[eV]에서의 C-O와 533.8[eV)에서의 C-O[C/O=8]를 확인하였다. ESR 분석에서 강한 진폭이 나타나는 곡선은 매우 약한 방전전력에 영향을 받은 포화상태를 나타낸다. 알림기를 함유한 -CH-CH=CH- 구조로 사료된다. 제조된 플라즈마 중합박막은 100[Hz]~200[kHz]의 주파수에서 비유전율이 3,5정도를 보이고 유전정접은 0.08의 낮은 값올 냐타내었다.

• 한국농공학회지
• /
• 제16권4호
• /
• pp.3611-3616
• /
• 1974

Alluvial plain of the coast of Kum river tail were found as being mostly consisted of weak foundation. The settlement of the ground, density and change of moisture content which were formed by the load due the construction of earth works were disclossed by the field investigations and laboratory tests. The results are as follow, 1) Banking materials are SM and soft soil stratum is CL. 2) Field moisture content; Wf=19-1.37c c; percentage of clay (less than 0.005mm) 3) optimum water content and maximum density of banking materials; rt=2.15$\mid$0.0165W(12%24%) 4) Density and moisture coutent of banking materials; rt=2.146-0.0095W (8%50%) 5) Density and moisture content of weak foundation; rt=2.06-0. 007W After construction (20%50%) Befor construction (40%60%) 6) Load and settlement of weak foundation; Everage settlement ratio; 12% of actual load p Maximum settlement ratio; 19% of actual load p Minimum settlement ratio: 5% of actual load p 7) Relation of cohesion and unconfined compression test value; c=1/2qu (qu<0.5kg/$\textrm{cm}^2$) c=1/3qu (qu<0.5kg/$\textrm{cm}^2$)

• 전자공학회논문지A
• /
• 제33A권3호
• /
• pp.117-125
• /
• 1996

The variation of the interfacial and the electrical properties of SiO$_{2}$TiW layers as a function of anneal temperature was extensively investigated. During the deposition of SiO$_{2}$ on TiW chemical bonds such as SiO$_{2}$, TiW, WO$_{3}$, WO$_{2}$ TiO$_{2}$ Ti$_{2}$O$_{5}$ has been created at the SiO$_{2}$/TiW interface. At the anneal temperature of 300$^{\circ}C$, WO$_{3}$ and TiO$_{2}$ bonds started to break due to the reduction phenomena of W and Ti and simultaneously the metallic W and Ti bonds started to create. Above 500$^{\circ}C$, a part of Si-O bonds was broken and consequently Ti/W silicide was formed. Form the current-voltage characteristics of Al/Sico$_{2}$(220$\AA$)/TiW antifuse structure, it was found that the breakdown voltage of antifuse device wzas decreased with increasing annealing temperature for SiO$_{2}$(220$\AA$)/TiW layer. When r, the insulating property of antifuse device of the deterioration of intermetallic SiO$_{2}$ film, caused by the influw of Ti and W.W.

• Tribology and Lubricants
• /
• 제15권1호
• /
• pp.77-82
• /
• 1999

The processing conditions fur the synthesis of platelet W $S_2$ lubricant powder through a solid-gas reaction were optimized. The mixture of tungsten and sulfur powders were sealed in a vacuum of 10$^{-6}$ torr, prior to heat-treating at 85$0^{\circ}C$ fur 8 days. The reaction product showed a well-developed platelet W $S_2$ powder with an average size of 3.8 ${\mu}{\textrm}{m}$. The TGA/DTA analysis of the synthesized W $S_2$ powder was performed up to 120$0^{\circ}C$ at a rate of 1$0^{\circ}C$/min in flowing air (100 ${\mu}{\textrm}{m}$/min) atmosphere. The weight loss was about 6% up to 120$0^{\circ}C$ compared to the original weight. A rapid weight loss of about 5% occurred in the temperature range of 44$0^{\circ}C$ to 66$0^{\circ}C$ and an exothermic peak observed due to the transition of W $S_2$ to W $O_3$. The synthesized W $S_2$powder was coated on the commercial deep grooved ball bearing (No. 6203) to examine the effect of W $S_2$, coating layer on the noise and endurance of the ball bearing. The level of noise obtained from W $S_2$, coated-ball bearing (56 ㏈) was higher. than the value (32 ㏈) occurred in the case of greece lubrication. The endurance of the ball-bearing assembled after the coating of W $S_2$ powder onto each part increased 50 times compared to the non-coated ball-bearing..

• 한국식품저장유통학회지
• /
• 제16권5호
• /
• pp.656-660
• /
• 2009

품질이 균일한 돔배기를 제조하기 위하여 염농도와 절임온도를 달리하여 상어육을 염절임하는 동안 품질변화를 측정하였다. 염농도를 1, 2, 3%로 조정하고 $4^{\circ}C$와 $18^{\circ}C$에서 절임한 상어육의 품질변화를 비교한 결과, 수분함량은 $4^{\circ}C$, 3%의 염농도에서 절임시 64.2%로 가장 높았으며, 염함량은 $18^{\circ}C$와 3%의 염농도로 절임 하였을 때 높게 나타났고, 보수력은 저온과 높은 염농도로 절임 하였을 때 높은 것으로 나타났다. 수분활성도는 고온에서 염농도가 높을수록 낮았으며, 색차는 저온과 높은 염농도로 절임 하였을 때 낮아 외관의 변화가 적었음을 알 수 있었다. 탄력성과 강도는 저온과 높은 염농도로 절임하였을 때 높게 나타났다. 따라서 직간법으로 상어육을 염절임할 때, 높은 농도에서 염절임한 상어육의 품질이 더 우수한 것으로 나타났으며, 염절임한 상어육이 염함량을 제외하고는 $4^{\circ}C$에서 절임한 상어육의 품질이 더 우수한 것으로 나타났다.

• 한국분말재료학회지
• /
• 제9권5호
• /
• pp.307-314
• /
• 2002

The high temperature deformation behavior of the activated sintered W powder compacts was investigated. The W compact showed the relative density of 94% with the average W grain size of $23\mutextrm{m}$ by activated sintering at $1400^{\circ}C$ for 1 hour. Compression tests were carried out in the temperature range of $900-1100^{\circ}C$ at the strain rate range of $10^{0}$/sec - $10^{-3}$/sec. True stress-strain curve and microstructure exhibited the grain boundary brittleness which was dependent on the compression test temperature. The activated sintered W compact showed that the maximum stress as well as the strain at the maximum stress was abruptly decreased as the test temperature increase from $900^{\circ}C$ to 1000 and $1100^{\circ}C$ regardless of the strain rate. The discrepancy of the microstructure in the specimen center was obviously observed with the increase of the test temperature. After compression test at $900^{\circ}C$ the W grain was severely deformed normally against the compression axis. However, after compression test at $1000^{\circ}C$ and $1100^{\circ}C$ the W grain was not deformed, but the microcrack was formed in the W grain boundary. The Ni-rich second phase segregated along the W grain boundary could be partly unstable over $900^{\circ}C$ and affect the poor mechanical property of the activated sintered W compact.