• 한국식품영양과학회지
• /
• 제32권6호
• /
• pp.840-846
• /
• 2003

참외피클을 제조하고자 해양심층수염, 천일염 및 정제염을 사용하여 참외의 절임시 이화학적, 관능적 특성에 대해 조사하였다. 참외의 절임기간 동안 중량, 수축률, 염도 및 pH의 변화는 소금의 종류에 따른 차이가 거의 없었다. 절임염수의 탁도는 천일염을 사용한 구에서 가장 높게 나타났으며, 해양심층수염과 정제염은 거의 변화가 없었다. 절임염수의 가용성 고형물 함량은 천일염을 사용한 것에서 정제염과 해양심층수염에서 보다 높게 나타났다. 절 임기간 동안 참외의 칼슘 함량은 해양심층수염과 천일염에서 절임 2일째에 약 4.3배, 3.7배까지 증가하였다. 심층수, 천일염을 사용한 참외 조직 감의 변화는 hardness가 정제염보다 다소 높게 나타났다. 관능검사 결과 해양심층수염을 절임염수로 사용한 참외의 색, 향, 맛, 물성 및 전반적인 기호도가 절임기간이 증가함에 따라 다른 천일염이나 정제염으로 절임한 참외보다 우수한 관능평점을 나타내었다.

• Bulletin of the Korean Chemical Society
• /
• 제35권8호
• /
• pp.2257-2262
• /
• 2014

$C_{60}$ is widely investigated because of its unique structure. But its applications in solid propellant seem to be relatively neglected. $C_{60}$ has more outstanding features than carbon black which is widely used as a catalyst ingredient of solid propellant. To combine the advantages of fullerene and lead salts, another good composite in propellant catalysts, we synthesized a kind of fullerene phenylalanine lead salt (FPL) and explored its thermal performances by differential thermal analysis (DTA) and thermogravimetry analysis (TGA). The results show it undergoes four exothermic processes started from 408 K. Combined TGA and X-ray diffractometer (XRD), the decomposition mechanism of FPL was derived by TG-IR and comparing IR spectra of FPL and its residues after burned to $327^{\circ}C$, $376^{\circ}C$ and $424^{\circ}C$, respectively. Effect of FPL on the decomposition characteristic of hexogen (RDX), a type of explosive in propellant, has been investigated using DTA at different heating rate, which shows the decomposition temperatures of the explosive are all reduced by more than 20 K. The corresponding activation energy ($E_a$) is decreased by $30kJ{\cdot}mol^{-1}$. So FPL has potential application as a combustion catalyst in solid propellant.

• 한국농공학회지
• /
• 제45권1호
• /
• pp.63-73
• /
• 2003

The settling of the dredged soil may vary with mineral composition, grain size distribution, initial water content and salt concentration of suspension of the site. A series of settling column test was performed to investigate the behaviour of solid suspension material from dredging and reclamation. Settling mode was divided into four types from the observation of interface and settling curves of clay minerals and marine clay samples, and the relationship charts of salt concentration and the initial water content were established to use in the dredging operation with any salt concentration. The critical initial water content which was defined as a threshold of zone settling and the consolidation settling was varied with salt concentration of water and was proportional to the plasticity of soil in sea water.

• 한국대기환경학회지
• /
• 제16권2호
• /
• pp.113-120
• /
• 2000

Effects of sea-salts on the properties of aerosol collected in a coastal region were studied by applying a gas-particle equilibrium model SCAPE to the measurement data from Korea Cheju Island in summer 1994. It was found that the observed higher ammonium concentrations in fine particles (PM2.5) than in TSP were caused by forced evaporation of ammonium in coarse fraction of aerosol by sea-salts and the degree of evaporation was quantified through an application of SCAPE. By subtracting the sea-salt fraction from the measured concentra-tions the changes of aerosol property were also studied. The concentrations of nitrate at both TSP and PM2.5 decreased when alkaline sea-salt fraction was removed from the measured data. Estimates of aerosol acidity increased for most samples with sea salt loadings, However in some cases with high mass fractions of sea-salt components the aerosol acidity of PM2.5 decreased slightly. This is though to be related with the formation of solid salt with the removal of sea-salts.

• 한국세라믹학회지
• /
• 제23권4호
• /
• pp.62-68
• /
• 1986

$(Pb_{1-x} La_x)(Zr_{0.65} Ti_{0.35})_{1-x/4}O_3$ (PLZT X/65/35) powders were prepared by molten salt synthesis using NaCl-K Cl and conventional calcining of oxides. The effects of molten salt on formation and charactrization of PLZT powder and on dielectric piezolectric and optical properties of PLZT ceramics were studied, The completed PLZT powder formation in the presence of fused salt was attained at 50-10$0^{\circ}C$ lower temperature than that in solid state reaction and the particle size of the powder made by molten salt synthesis was markedly increased with increasing calcining temperature. The substitution of Na and/or K ions in NaCl-KCl for Pb ion in process of molten salt synthesis was increased with increasing La concentration Z. These substituted Na and/or K ions were identified as the origins of decreasing coupl-ing factor and optical transmittance of PLZT ceramics.

• 한국재료학회지
• /
• 제11권11호
• /
• pp.991-996
• /
• 2001

This study is the manufacture of solid lubricant oilless bearing using sintered parts. PTFE was as organic solid lubricant and $MoS_2$ as inorganic solid lubricant, and its characteristics were studied. Thickness of lubricant was suited 25~$100\mu\textrm{m}$ for lubricant characteristics. Curring temperature of MoS_2$ film was 12$0^{\circ}C$, 2 hours and that of PTFE film was $260^{\circ}C$, 20 minutes. The solid weight and solid volume of $MoS_2$ film was 51.7% and 27.4%, and that of PTFE was 44.9% and 24.3%. Chemical resistant of PTFE solid lubricant oilless bearing was excellent as salt test was 520hours, and usable temperature range was $-200~+280 ^{\circ}C$. Conduction of electricity can be increase by addition of graphite or $$\alpha$- PbO_2$. The electric conductivity was 100~180$\Omega$.

• 한국식품과학회지
• /
• 제34권1호
• /
• pp.1-7
• /
• 2002

여름무 품종별 무의 절임 특성을 알아보기 위해, 절임 염수(소금 농도: 15%) $(2{\times}2{\times}2\;cm)$로 절단한 3 품종('백봉', '관동', '92343')의 여름 무를 2배의 절임 염수에 넣어 $15^{\circ}C$에서 절이면서 절임 중 깍두기 무의 염도, 중량, 수분함량, 가용성 고형물 함량 및 경도(TPA)를 알아보았다. 3 품종의 깍뚜기 무 모두 절임 시간이 경과 될수록 염도, 가용성 고형물 함량은 증가하였으며, 중량 및 수분함량은 감소하는 경향을 나타내었고, texture analyser에 의한 경도는 감소하는 경향을 나타내었다. 깍두기 무의 소금 농도가 3%에 달할 때까지의 절임 염수의 소금 농도에 따른 최적 절임 시간은 '백봉'은 3시간, '관동' 및 '92343'은 4시간이 적당하였다. 절이는 동안 중량 감소율은 '백봉'이 약간 컸고, '관동' 및 '92343'은 비슷하였다. '관동'과 '92343'은 '백봉'에 비해 수분함량이 적었고, 가용성 고형물 함량이 많았으며 경도가 높았으며 '백봉'은 수분함량이 많고 가용성 고형물 함량이 적었고 경도가 낮았다. 한편, 절임무의 계절별 특성을 알아보고자 '백봉' 및 '백관' 2 품종에 대해 10% 또는 15%의 절임 염수에서 절이는 동안의 깍두기 무중의 염도가 3%에 달하였을때의 절임무 특성을 계절별로 알아본 결과, '백봉'은 염침투 속도, 중량 감소정도, 가용성 고형물 함량 및 경도가, '백광'은 염침투 속도, 중량 감소정도 및 경도가 가을이 봄 및 여름에 비해 높게 나타났으며, 수분 함량은 두 품종 모두 봄 및 여름이 가을에 비해 높게 나타났다.

• 한국환경과학회:학술대회논문집
• /
• 한국환경과학회 2003년도 International Symposium on Clean Environment
• /
• pp.135-138
• /
• 2003

Based on solid phase extraction, gas chromatography and mass spectrometry procedure for determining phenol and its derivatives in natural water was presented. In solid phase extraction, three types of techniques using solid phase adsorption material were treated with acid and salt, and converted second portion of acetyl derivatives. Under the these condition, extraction efficiency and detection ability dependent on extraction methods were discussed. Obtained results using optimized solid phase extraction techniques showed more convenience, simplifier and lower cost than the conventional analytical methods with holding wide dynamic range and lower detection limits.

• 한국식품영양과학회지
• /
• 제22권3호
• /
• pp.317-322
• /
• 1993

배추의 염절임(5$0^{\circ}C$, 25% 소금용액)및 탈염(5$0^{\circ}C$, 증류수)과정중 침지시간에 따른 물질이동을 수분흡수 또는 유출, 소금유출 또는 흡수 및 환원당유출로써 조사하였다. 염절임 과정중 수분유출과 소금흡수는 초기 6시간 침지과정에서 빠르게 이루어진 후 증가현상이 둔화되었다. 24시간 염절임 과정 후 초기 100g 배추무게당 수분유출과 소금흡수는 각각 33.35g과 6.26g이었다. 염절임과정중 수분함량은 94.29%에서 83.11%로 줄어들었다. 환원당농도 역시 29.2mg/$m\ell$에서 6.5mg/$m\ell$로 낮아졌으며, 침지시간(hr) 의 평방근을 이용한 직선식은 Y=30.1841-5.0269√t이었다. 24시간 염절임 한후 탈염과정에서의 수분흡수와 소금유출은 초기 4시간 침지과정에서 빠르게 이루어진 후 직선적으로 계속적인 증가현상을 나타내었다. 12시간 탈염과정 후 초기 100g배추 무게당 수분흡수는 20.82g이 었으며, 소금유출은 9.14g이었다. 탈염과정에서의 소금유출이 염절임과정의 소금흡수보다 높은 이유는 염절임 및 탈염과정에서 배추의 고형분 유출에 기인된 것이었다. 12시간의 탈염공정으로 김치 제조시 배추의 적정 소금농도인 3%로 낮출수 있었다. 이때의 환원당농도는 1.6mg/$m\ell$로 낮아졌으며, 침지시간의 평방근을 이용한 직선식은 Y=6.7854-1.5992√t로써 염절임 공정의 기울기값 (-5.0269)과 비교할때 탈염공정에서의 환원당 겉보기 유출속도는 낮았다.

• 한국전기화학회:학술대회논문집
• /
• 한국전기화학회 2002년도 추계총회 및 학술발표회
• /
• pp.61-61
• /
• 2002