• Nuclear Engineering and Technology
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• v.10 no.4
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• pp.223-229
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• 1978

A typical abnormal standard dose response curve of nearly convex form. often encountered in insulin radioimmunoassay (IRIA) has been analyzed by varying incubation conditions. The cause of such abnormality has been turned out to be the results of an incomplete equilibrium between the two reactants. By careful control of the temperature of serum sample an immediate cause of sharp deviation of B/F value of tile sample tube from the measurable range in the standard curve has also been investigated. The two main troubles have been proven to be stemed from incubation conditions. Incubation at 4$^{\circ}C$ for 48 hrs is emphasized for IRIA.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.446-450
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• 1996

To investigate the effect of heating conditions on the polymerization of methyl linoleate, the esters were heated at $60^{\circ}C,\;90^{\circ}C,\;120^{\circ}C$ and $150^{\circ}C$, respectively, with sparging oxygen for different periods of time. On the basis of the peroxide curve obtained at each of the four temperatures, four heating times were chosen for the analysis of the polymers and total oxidation products. Significant linear relationships were found between polymer contents and total oxidation product contents. The contents of polymers and their linkage types were analyzed by High Performance Size Exclusion Chromatography. The polymers formed at four temperatures were qualitatively identified as dimers. The dimers with peroxide linkages were detected from methyl linoleate oxidized at $60^{\circ}C\;and\;90^{\circ}C$ but they were not detected from methyl linoleate oxidized at $120^{\circ}C\;and\;150^{\circ}C$. Therefore, all dimers formed at $120^{\circ}C\;and\;150^{\circ}C$ seemed to be the ones with ether linkage or carbon to carbon linkage. The degradation rate of the dimers with peroxide linkages at $90^{\circ}C$ was faster than at $60^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.19 no.2
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• pp.176-180
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• 1987

The sorption characteristics of dried garlic flakes stored at various relative humidity and storage temperature were studied. At low relative humidity below RH 51%, the sorption equilibrium was easily attained, whereas at higher relative humidity above RH 67%, the flakes were browned by higher equilibrium moisture content. The flakes were browned at relative humidity above 67% at $20^{\circ}C$ and $35^{\circ}C$, above 84% at $5^{\circ}C$, respectively. The moisture contents of monolayer value for the flakes were ranging from 5.80% to 6.20% (DB) with varying temperatures. And the necessity of moisture-proof packaging material suggested for the long term storage of the flakes because the lower moisture content and storage temperature, the higher driving force of wetting. Regression equation for browning rate prediction with relative humidity and storage temperature of the flakes was determined.

• Fire Science and Engineering
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• v.10 no.3
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• pp.3-9
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• 1996

The Polyimide thin films based on PMDA and 4,$4^{\circ}$'-DDE were fabricated by VDPM, and their heat resistance characteristics were invastigated by TGA(Thermogravimetry Analyzer). It was found that deposition rate decreased with increasing substrate temperature and the thin films were not fabricated over the substrate temperature of $70^{\circ}$. $T_{TG}$ of weight loss temperature is $565^{\circ}$, $397^{\circ}$ and $210^{\circ}$ at the substrate temperature of $20^{\circ}$, $40^{\circ}$ and $70^{\circ}$, respectively. It is realized that the endurace temperature for 20,000 hour of thin films fabricated at $20^{\circ}$ and $40^{\circ}$ is $230^{\circ}$ and $200^{\circ}$, respectively.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.4 no.1
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• pp.11-19
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• 2008

Groundwater flow in confined aquifer and heat transport in underground geologic media are using same governing equation(line source) like well fuction. Therefore the conventional slope method using only later data obtained from in-situ thermal response test to determine the thermal conductivity of vertical geothermal heat exchanger(GHEX) is basically identical with one of Theis straight line method of aquifer test under artesian condition. In case that the pumping rate(Q, $m^3$/d) and drawdown(s,m) which are used for input data of existing hydrogeologic computer programs for aquifer test are replaced and converted to supplying heat energy per unit length of bore hole(Q/L,w/m or Kcal/h.m) and temperatures (T,$^{\circ}C$)measured at in and out-let of GHEX as in put data respectively, thermal conductivity around geothermal heat exchanger can be easily estimated without any special modification of the existing hydrogeologic computer program. Two numbers of time series temperature variation data obtained from in situ geothermal response test are analized using Theismethods(standard curve and straight line method) by using existing aquifer test program and conventional Slope method proposed by ASHRAE. The results show that thermal conductivity values estimated by two straight methods are identical and the difference of estimated values between standard curve methods and Slope method are also within acceptable ranges. In general,the thermal conductivity estimated from Theis straight linemethod gives more accurate value than the one of Slope method due to that Slope method uses only visual matching otherwise Theis method uses automatic curve matching estimation with reducing RSS.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.462-462
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• 2017

유량은 기후적 요인과 인간활동 요인에 의하여 변동된다. 특히 우리나라는 지난 30년 동안 전지구적인 기후변화와 특정지역에서의 인간활동의 변화가 급격하게 진행된 바 있으므로, 합리적인 수자원 계획을 수립하기 위해서는 두 가지 요소들로 인한 유량의 변동량을 정량적으로 분리하여 분석할 필요가 있다. 또한 우리나라와 같이 연강수량의 대부분이 특정 계절에 집중되는 국가나 유역에서는 월별, 계절별 및 년별로 구분된 수문분석을 시행하여야 보다 실질적인 수자원 관리계획을 수립할 수 있다. 그러나 유량의 변동량을 특정 원인별로 구분하여 분석하고자 하는 연구는 기존의 홍수나 가뭄 자체에 관한 연구에 비해 미미한 형편이며, 다양한 시간단위를 이용한 원인별 유량 변동량의 산정에 관한 연구는 더욱 찾아보기 힘들다. 따라서 본 연구에서는 기후변화로 및 인간활동으로 인한 유량 변동량을 정량적으로 분리하기 위하여 수문모형(hydrological model)을 이용한 방법과 수문학적 민감도 (hydrological sensitivity) 분석 방법을 소양강 상류유역 및 섬강 유역에 대해 적용하고 유량 변동량의 결과를 월별, 분기별 및 년별로 구분하여 제시하였다. 먼저 두 유역에 대한 기후변화 및 인간활동의 양상을 강수, 온도, 유량, 인구변화, 불투수층 변화의 추세를 통해 파악하였으며, 인간활동으로 인해 발생되는 급진적인 변동점을 탐색하기 위해 이중누가곡선, Pettitt 검정 및 베이지안 변동점 (Bayesian change point) 분석을 시행하였다. 탐색된 변동점을 활용하여 수문모형에 의한 유량 변동량을 정량화하기 위하여 변동점 이전 구간에 대해 보정 및 검증된 SWAT모형을 사용하였으며, 6가지의 Budyko 곡선 함수들로부터 각각 유량 변동량을 산정하여 수문모형에 의한 유량 변동량을 검증하였다. 최종적으로 수문모형을 이용한 방법을 통해 두 유역에 대한 기후변화 및 인간활동으로 인한 유량 변동량을 정량화하였다. 소양강 상류유역은 기후변화로 인한 유량 변동량이 인간활동으로 인한 유량변동량보다 상대적으로 크게 산정되었으며, 섬강 유역은 소양강 유역과 반대의 결과를 보이는 것으로 분석되었다. 특히 본 연구에서는 해당 분석결과를 월별 및 분기별로 구분하여 제시함으로써, 향후 특정 지역 및 시기에서의 합리적인 수자원 관리계획의 수립에 활용될 수 있는 기초적인 자료를 제공하였다.

• Journal of Korean Society of Forest Science
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• v.60 no.1
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• pp.30-36
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• 1983

Plywood, the representative interior decorative or structural material, is so inflammable that it may cause big fires. Therefore, it is required inevitably to manufacture the "Fire retardant treated plywood", and it will be a study on the redrying of treated plywood that we ought to solve. This study was carried out to investigate the absorption of 20% $(NH_4)_2HPO_4$ solution into the soaked plywoods by hot/cold soaking for 3/3, 6/3, 9/3 and 12/3 hours and to study drying process with drying curves and drying rates by press-drying at the platen temperature of 130, 145, 160 and $175^{\circ}C$. Solution absorption of plywoods in hot/cold soaking method increased steadily with the prolonged soaking time, and water absorption is higher than DAP absorption, and then chemical retention (DAP) exceeded the minimum retention [$1.125kg/(30cm)^3$] even in the shortest soaking treatment. Drying curves of water-soaked plywoods inclined more steeply than those of DAP soaked plywoods. And the drying proceeded rapidly with the increase in platen temperature and terminated in 2.5-4 minutes at the temperature of 160 and $170^{\circ}C$. Drying rate also increased generally with the increase of platen temperature. So it was at $175^{\circ}C$ in DAP-soaking and at $160^{\circ}C$ in water-soaking when the drying rate became above 10%/min.

• Solar Energy
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• v.16 no.2
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• pp.113-122
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• 1996

This study presents experimental results of heat transfer characteristics of P.C.M. during outward melting process in a vertical cylinder. The experiment was carried out in six conditions, i. e., three different inlet temperature($7^{\circ}C,\;4^{\circ}C\;and\;1^{\circ}C$) and two directions of working fluid(upward and downward). Melting P.C.M. produced a bell-shaped phase change interface. When the inlet temperature was $7^{\circ}C$, the lower region remained at $4^{\circ}C$ until the temperature of upper region reached $4^{\circ}C$. This was due to the state of maximum density of the lower region. When the direction of the working fluid in the case of $7^{\circ}C$, inlet temperature, was upward, the rate of melting and the total melting energy were higher than when it's direction was downward. But the rate of melting and the total melting energy appeared higher value as it's direction was downward when the inlet temperature is $4^{\circ}C$ and $1^{\circ}C$.

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.350-355
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• 2018

In this study, the effect of biomass torrefaction on the thermal and catalytic pyrolysis of cork oak was investigated. The thermal and catalytic pyrolysis behavior of cork oak (CO) and torrefied CO (TCO) were evaluated by comparing their thermogravimetric (TG) analysis results and product distributions of bio-oils obtained from the fast pyrolysis using a fixed bed reactor. TG and differential TG (DTG) curves of CO and TCO revealed that the elimination amount of hemicellulose in CO increased by applying the higher torrefaction temperature and longer torrefaction time. CO torrefaction also decreased the oil yield but increased that of solid char during the pyrolysis because the contents of cellulose and lignin in CO increased due to the elimination of hemicellulose during torrefaction. Selectivities of the levoglucosan and phenolics in TCO pyrolysis oil were higher than those in CO pyrolysis oil. The content of aromatic hydrocarbons in bio-oil increased by applying the catalytic pyrolysis of CO and TCO over HZSM-5 ($SiO_2/Al_2O_3=30$). Compared to CO, TCO showed the higher efficiency on the formation of aromatic hydrocarbons via the catalytic pyrolysis over HZSM-5 and the efficiency was maximized by applying the higher torrefaction and catalytic pyrolysis reaction temperatures of 280 and $600^{\circ}C$, respectively.

• Journal of the Korean Chemical Society
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• v.38 no.12
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• pp.880-884
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• 1994

An indirect spectrophotometric method, presumably heretofore unmentioned, for the rapid determination of COD in the presence of chloride of high concentration is described. The alkaline sample is refluxed to react with a definite amount of permanganate, present in excess. A photometric measurement at 535 nm for the extent of the fading of the permanganate color after refluxing completes the procedure. The optimum conditions which give the absorbance-concentration plot the maximum linearity and slope in the range of 0∼5 ppm COD are as follows: reflux at $100\circC$ for 10 min in the presence of 0.15 mM permanganate and 0.2% NaOH with a sample size of 5 ml. An overall running time was less than 15 min. The t-test reveals that the proposed method is not significantly different from the official method.