• 대한화학회지
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• 제36권2호
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• pp.191-196
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• 1992

$CHCl_3,\;CHCl_3 : CH_2Cl_2$(1:1) 및 $CH_2Cl_2$ 용매 중에서 N,N-dimethylaniline(N,N-DMA)과 iodine간의 반응을 전도도법을 이용하여 속도론적으로 조사하였다. 유사 1차반응 속도상수($k_{obs}$) 및 2차반응 속도상수($k_{obs}$/[N,N-DMA])가 N,N-DMA 농도 의존성을 보였다. 실험적으로 구한 2차반응 속도상수는 N,N-DMA 농도 증가와 더불어 증가하였다. 이러한 결과를 반응 중간 생성물로서 charge tranfer complex의 생성에 기인하는 것으로 보고, 반응 scheme의 설정과 속도상수식의 유도로부터 complex 생성에 따른 평형상수와 변환에 따른 활성화 파라미터를 계산하였다. 평형상수는 용매의 유전상수의 증가와 더불어 감소하였으며, 1.9${\sim}$4.2$M^{-1}$의 값을 보였다. 또한 변환의 빠르기는 용매의 극성에 크게 의존하였으며, ${\Delta}H^{\neq}$값은 6.3-12.6kJ/mol, ${\Delta}S^{\neq}$값은 약 -234J/mol K의 큰 음의 값을 나타내었다.

• Food Science and Biotechnology
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• 제15권3호
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• pp.404-408
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• 2006

Feasibility of surface plasmon resonance (SPR) method to evaluate soybean frying oil quality was evaluated. Free fatty acid value, p-anisidine value, conjugated dienoic acid content, conjugated trienoic acid content, peroxide value, iodine value, total polar compound (TPC), ratio of unsaturated fatty acid to saturated fatty acid, refractive index, dielectric constant, smoking point, and L, a, and b of Hunter color system were selected as parameters related to conventional evaluation of soybean frying oil quality. SPR scale mapped with conventional quality parameters well described free fatty acid value, conjugated dienoic acid content, dielectric constant, TPC, and b of Hunter color system, as shown by correlation and linear regression analyses.

• Natural Product Sciences
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• 제11권4호
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• pp.225-228
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• 2005

four varieties of ground nut (Arechis hypogea) were collected from different areas of Pakistan (Tillagang, Gujar khan, Hanoi and Pipplan) from Punjab province. The oils were extracted for the evaluation of lipid. Physico-chemical values of oils were determined like refractive index, peroxide value, unsaponifiable matter, acid value, iodine value, free fatty acid and ester value. The lipid profile as indicated by GLC showed that Palmitic acid ranged from 8.2-8.8%, proportions of oleic acid and linoleic acid varied from 57.8-59.87% and 22.5-24.1% respectively. Gujar khan variety of peanut has higher % age of oil (56.79). The higher yield of oil in this variety is not at the cost of any nutritional quality of peanut oil.

• 한국식품조리과학회지
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• 제18권3호
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• pp.340-348
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• 2002

Changes in the physicochemical properties of frying oil after single or repeated use in foodservice establishments were studied. The experiment was designed to simulate the practical frying practice based on a survey from the dieticians in the food service establishments. Used oils came from the single frying of mackerel and the sequential frying of 1) potato and mackerel, 2) battered pork and mackerel, and 3) potato, battered pork, and mackerel. The used oil samples were analyzed and compared with the fresh one. Oil quality parameters such as acid value, peroxide value, thiobarbituric acid value, iodine value, viscosity, and color were measured at each step of deep-fat frying. The physicochemical properties of the frying oils have been more or less affected by the frying conditions. However, the used oils resulted from the experimental trials were within the range of acceptance as indicated by the acid and peroxide values.

• 한국산학기술학회논문지
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• 제12권8호
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• pp.3572-3578
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• 2011

양전자방출단층촬영에서 표준섭취계수는 종양의 진단에 사용이 되는 지표이다. 표준섭취계수는 여러 인자에 의해 변화한다. 본 연구에서는 Philips사의 GEMINI TF PET/CT를 이용하여 물질에 따른 영상의 왜곡 및 표준섭취계수의 변화에 대하여 실험하였다. 물질별 표준섭취계수의 변화는 스테인레스보정물은 1.8, 스텐트는 1.4, 요오드성조영제는 2.4, 황산바륨은 2.6, 석고는 1.6, 파라핀은 1.4 이였다. 황산바륨 일수록 농도가 높을수록 영상의 왜곡은 크게 나타났다. 실험의 결과 원자번호가 낮은 금속성 물질이나 농도가 낮은 조영제의 경우 큰 영향은 없었다. 그러나 검사전 반드시 금속성 물질을 제거하거나 조영제의 유무를 확인하여 영상의 왜곡 및 표준섭취계수의 변화를 최소화 해야할 것이다.

• 공업화학
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• 제9권6호
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• pp.835-841
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• 1998

활성탄제조에 적합한 유연탄과 무연탄을 선정하여 활성탄을 제조하고, 유연탄과 무연탄의 혼합비율을 달리하였을 때 나타나는 물리적 특성을 규명하였다. 유연탄에 무연탄인 Dandong탄을 25, 50, 75 wt.%로 혼합하여 활성탄을 제조할 경우 활성탄 수율은 Dandong탄의 함량 증가에 따라 증가되었으나 겉보기 밀도는 유연탄의 성상에 관계없이 일정하게 나타났고, 흡착력을 나타내는 요오드가는 반대로 감소되었다. Fushun탄과 Dandong탄을 75:25 wt.%로 혼합한 후 활성화조건에 따른 기공특성을 관찰한 결과 기공분포는 활성화온도 $850{\sim}900^{\circ}C$에서 $20{\AA}$ 이하의 미세기공이 발달되었고, $830^{\circ}C$와 $950^{\circ}C$에서는 중간기공이 발달되었다. 또한 제조된 석탄혼합 활성탄의 성능을 고찰하기 위해 상용화된 제품과 실험을 통해 흡착성능을 비교하였는데 경쟁력있는 흡착력을 갖는 것으로 확인되었다. 따라서 활성탄 제조시 탄화 및 활성화 과정에서 여러 가지 조업변수와 원료탄 혼합효과에 의해 그 특성이 달라짐이 확인되었다.

• 한국식품과학회지
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• 제27권2호
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• pp.205-209
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• 1995

국내에서 생산된 정제 대두유의 열, 산화 안정성을 향상시키고 풍미, 물성의 개량과 이용도를 높이기 위하여 수소첨가에 의한 식용경화 대두유 제조시 반응 조건을 달리하여 주요 지방산 조성, 옥소가 및 trans 이성체의 생성에 미치는 영향을 조사하였다. $180^{\circ}C$의 반응조건에서 trans 산의 생성은 압력 $3.0{\;}kg/cm^{2}H_{2}$에서 $0.5{\;}kg/cm^{2}H_{2}$에서 보다 6.2배 증가하였고 linolenic acid는 감소하였다. 그러나 경화온도 $200^{\circ}C$의 경우 압력 $0.5{\;}kg/cm^{2}H_{2}$에서 $3.0{\;}kg/cm^{2}H_{2}$보다 trans 이성체 생성이 4.6%가 많았으며, linolenic acid, linoleic acid함량은 각각 0.51%, 2.5%가 감소하였다. 경화온도 $180^{\circ}C$, 압력 $3.0{\;}kg/cm^{2}H_{2}$와 sulphur 4 ppm을 첨가한 조건에서 옥소가와 linolenic acid가 감소하여 유리하였으나, trans 이성체의 생성이 가장 많아 불량하였다. 그러나 경화온도 $200^{\circ}C$, 압력 $0.5kg/cm^{2}H_{2}$와 $3.0kg/cm^{2}H_{2}$의 조건하에서 trans 이성체의 생성이 비교적 적게 생성되었고, 옥소가와 linolenic acid도 감소되어 최적 조건이라 생각된다.

• 한국재료학회지
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• 제20권10호
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• pp.535-542
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• 2010

In this study, we used coal-based activated carbons and charcoal as startingmaterials, phenolic resin (PR) as a binder, and TOS as a titanium source to prepare $TiO_2$ combining spherical shaped activated carbon photocatalysts. The textural properties of the activated carbon photocatalysts (SACP) were characterized by specific surface area (BET), energy dispersive X-ray spectroscopy (XRD), scanning electron microscopy (SEM), iodine adsorption, strength intensity, and pressure drop. The photocatalytic activities of the SACPs were characterized by degradation of the organic dyes Methylene Blue (MB), Methylene Orange (MO), and Rhodamine B (Rh. B) and a chemical oxygen demand (COD) experiment. The surface properties are shown by SEM. The XRD patterns of the composites showed that the SACP composite contained a typical single, clear anatase phase. The EDX spectro for the elemental indentification showed the presence of C and O with Ti peaks. According to the results, the spherical activated carbon photocatalysts sample of AOP prepared with activated carbon formed the best spherical shape, a high BET surface area, iodine adsorption capability and strength value, and the lowest pressure drop, and the photocatalytic activity was better than samples prepared with charcoal. We compared the degradation effects among three kinds of dyes. MB solution degraded with the SACP is better than any other dye solutions.

• Bulletin of the Korean Chemical Society
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• 제18권12호
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• pp.1274-1280
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• 1997

The photodissociation dynamics of CH2I2 has been studied at 304 nm by state-selective photofragment translational spectroscopy. Velocity distributions, anisotropy parameters, and relative quantum yields are obtained for the ground I(2P3/2) and spin-orbit excited state I*(2P1/2) iodine atoms, which are produced from photodissociation of CH2I2 at this wavelength. These processes are found to occur via B1 ← A1 type electronic transitions. The quantum yield of I*(2P1/2) is determined to be 0.25, indicating that the formation of ground state iodine is clearly the favored dissociation channel in the 304 nm wavelength region. From the angular distribution of dissociation products, the anisotropy parameters are determined to be β(I)=0.4 for the I(2P3/2) and β(I*)=0.55 for the I*(2P1/2) which substantially differ from the limiting value of 1.13. The positive values of anisotropy parameter, however, show that the primary processes for I and I* formation channels proceed dominantly via a transition which is parallel to I-I axis. The above results are interpreted in terms of dual path formation of iodine atoms from two different excited states, i.e., a direct and an indirect dissociation via curve crossing between these states. The translational energy distributions of recoil fragments reveal that a large fraction of the available energy goes into the internal excitation of the CH2I photofragment; < Eint > /Eavl=0.80 and 0.82 for the I and I* formation channels, respectively. The quantitative analysis for the energy partitioning of available energy into the photofragments is used to compare the experimental results with the prediction of direct impulsive model for photodissociation dynamics.

• 한국조리학회지
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• 제24권2호
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• pp.79-86
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• 2018

The purpose of current study was to evaluate the oxidative stability of soybean oil after frying according to storage temperature. The soybean oil after 10 times deep fat frying with potato sticks (10% w/w of oil) were stored during 10 days at 30, 60 and $90^{\circ}C$ and chemical properties were determined. The acid value and peroxide value were the highest and the iodine value were the lowest when the oil stored at $90^{\circ}C$. Expecially, the production rate of peroxide was fast at over $60^{\circ}C$. According to the results, frying oil should not be stored for more than 6 days at $30^{\circ}C$ after use. Since the oil used had already produced unstable peroxides, oxidation could proceed relatively quickly even at low temperatures. Therefore, it is desirable to keep the used oil at a temperature as low as possible.