• The Korean Journal of Pesticide Science
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• v.8 no.1
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• pp.30-37
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• 2004

This study estimated the correlation between surface area/weight ratios and pesticide residues in two varieties of tomato, mini tomato and tomato. The ratios of surface area/weight of mini tomato and tomato were $2.15cm^2g^{-1}$ and $1.00cm^2g^{-1}$ respectively. Pesticide residues were measured with four kinds of pesticide, chlorothalonil WP, chlorothalonil SC, oxadixyl WP, thiophanate-methyl WP. Ie residue amount of mini tomato was $1.4\sim2.4$ times higher than those in tomato regardless of the application date and frequency. The ratios of surface area/weight on tomato varieties played a key role for determining pesticide residue.

• Korean Journal of Agricultural Science
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• v.45 no.2
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• pp.265-282
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• 2018

The purpose of this research was to produce symmetric (Saturated-Unsaturated-Saturated, SUS) triacylglycerol (TAG) using palm stearin fraction oil (PSFO) and high oleic sunflower oil (HOSO) as substrates to replace cocoa butter. PSFO was blended with HOSO (1 : 2 weight ratio), and $lipozyme^{(R)}$ TLIM (20 weight % of the substrate) was added. Interesterification was carried out in a shaking water bath at $55^{\circ}C$ at 220 rpm for 6 hours. The response surface methodology (RSM) through the central composite face design was employed to observe the optimized SUS-TAG. The independent factors were the reaction temperature ($X_1$: 65, 75 and $85^{\circ}C$), reaction time ($X_2$: 1, 3 and 5 hours) and ratio of TLIM ($X_3$: 10, 15 and 20 weight %). The dependent variables were $Y_1$ = Saturated-Unsaturated-Unsaturated (SUU, area %), $Y_2=SUS$ (area %), $Y_3$ = Saturated-Saturated-Unsaturated (SSU, area %), $Y_4$ = Unsaturated-Unsaturated-Unsaturated (UUU, area %), and $Y_5=sn-2$ unsaturated fatty acid (area %). The optimal conditions from the central composite face design minimized acyl migration while maximizing the presence of unsaturated fatty acid at the sn-2 position (73.43 area %). The optimal conditions were $X_1=65^{\circ}C$, $X_2=1hour$, and $X_3=20weight%$. As a result of the response surface analysis, the lack of fits was found as $Y_1=0.622$, $Y_2=0.438$, $Y_3=0.264$, $Y_4=0.526$, and $Y_5=0.215$, and their $R^2$ were 0.897, 0.944, 0.826, 0.857, and 0.867, respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.86-89
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• 2003

It is recognized that reinforcement corrosion is the main distress behind the present concern regarding concrete durability. In this study, to confirm corrosion of reinforced concrete affected by thickness of cover, kinds of surface coating, measured electric potential, ratio of corrosion area, weight reduction, corrosion velocity of steel bar under environment of complex deterioration. The results showed that an increase in age also increases corrosion of steel bar. Ratio of corrosion area is largely related to ratio of weight reduction. as well, corrosion of steel bar by thickness of cover is superior to l0mm thick than 20mm thick. It showed that an increase in thickness of cover prevent steel bar from deteriorating. The results of this study showed that corrosion velocity was affected by thickness of cover, kinds of surface coating. data on the development of corrosion velocity made with none, organic B, organic A, inorganic B, and inorganic A is shown.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.2
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• pp.249-255
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• 2011

It is complicate problem to optimize removing natural organic matter (NOM) by activated carbon in drinking water treatment because the activated carbon has heterogeneous surface area and pore structure. Seven different coals based activated carbons which have different pore structures were used in the study. Sand filtered effluents which normally used as GAC adsorber influent were used. The molecular weight distribution showed that most of the NOM was bigger than 10,000Da. In this study, systematical approaches such as characteristics of surface area and pore volume were evaluated on NOM adsorption. Especially, the adsorption capacities for NOM were evaluated by effect of micro-pores and meso-pores in surface area and pore structure. The results show that the higher ratio of meso-pore compare to the micro-pore has not only the better adsorption capacities for NOM but also the higher strongly-adsorbable fraction. Therefore, the overall adsorption capacity is increased with higher meso-pore ratio with existing of reasonable micro-pore surface area and volume.

• Journal of the Korean Society of Tobacco Science
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• v.5 no.2
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• pp.33-38
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• 1983

This experiment was conducted to investigate effects of fertilizers on leaf surface lipid(LSL) , and relationship between growth characteristics and LSL of aromatic tobacco, cv. Sohyang, grown in pots with 3 rates of N, P and K. With increasing the amount of applied nitrogen from 3 to 6kg110a, the contents of LSL per plant and per leaf area were decreased For maximum LSL Per plant and per leaf area nitrogen of 3kg/10a was required ,There were lit tie affected by P and K. Leaf weight per plant and mean leaf area were correlated significantly and positively with LSL per plant, but thickness of largest leaf negatively. Specific leaf weight and leaf dry weight /leaf fresh weight ratio were correlated significantly and positively with LSL per leaf area, but mean leaf area negatively.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.3
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• pp.100-107
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• 2001

Miro propulsion device is a literally very small propulsion system The reason why such a small propulsion system is required is that micro satellites are considered as substitutions for conventional satellites to reduce cost; the fabrication of micro satellites enables us to produce mass production Microrockets have relatively high values of thrust/weight ratio due to the cube law; weight is proportional to volume and thrust is proportional to area. Accordingly, downsizing makes the ratio of thrust/weight ratio high However, conventionally ignorable facts are not negligible any more in small scale systems. for chemical micro rockets, downsizing causes lots of heat loss as surface to volume ratio increases, which results in the destruction of radical ions. For thrusters using plasma, the generation of strong magnetic field for plasma is very difficult. Also, in the aspect of flow dynamics, the effects of drag and viscosity are important parameters in low Re flows. When these problems are solved, micro propulsion systems can be commercialized and result in spin-off effects in many fields.

• Carbon letters
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• v.10 no.3
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• pp.217-220
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• 2009

In this study, porous electrospun carbon fibers were prepared by electrospinning with PAN and $MgCl_2$, as a MgO precursor. MgO was selected as a substrate because of its chemical and thermal stability, no reaction with carbon, and ease of removal after carbonization by dissolving out in acidic solutions. $MgCl_2$ was mixed with polyacrylonitrile (PAN) solution as a precursor of MgO with various weight ratios of $MgCl_2$/PAN. The average diameter of porous electrospun carbon fibers increased from 1.3 to 3 ${\mu}m$, as the $MgCl_2$ to PAN weight ratio increased. During the stabilization step, $MgCl_2$ was hydrolyzed to MgOHCl by heat treatment. At elevated temperature of 823 K for carbonization step, MgOHCl was decomposed to MgO. Specific surface area and pore structure of prepared electrospun carbon fibers were decided by weight ratio of $MgCl_2$/PAN. The amount of hydrogen storage increased with increase of specific surface area and micropore volume of prepared electrospun carbon fibers.

• Bulletin of the Korean Chemical Society
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• v.16 no.6
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• pp.498-503
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• 1995

The adsorption behaviors of two major components purified, endo Ⅱ and exo Ⅱ, from Trichoderma viride were investigated using microcrystalline cellulose with different specific surface area as substrates. Adsorption was found to apparently obey the Langmuir isotherm and the thermodynamic parameters, ΔH, ΔS, and ΔG, were calculated from adsorption equilibrium constant,K. The adsorption process was found to be endothermic and an adsorption entropy-controlled reaction. The amount of adsorption of cellulase components increased with specific surface area and decreased with temperature and varied with a change in composition of the cellulase components. The maximum synergistic degradation occurred at the specific weight ratio of the cellulase components at which the maximum affinity of cellulase components obtains. The adsorption entropy and enthalpy for respective enzyme system increased with specific surface area increase. The adsorption entropy was shown to have a larger value with enzyme mixture.

• The Korean Journal of Food And Nutrition
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• v.17 no.2
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• pp.220-228
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• 2004

Dynamic headspace purge conditions were investigated to obtain minimum loss of high volatile compounds by breakthrough and maximum recovery of low volatile components of roasted perilla seed oil (RPSO). A response surface methodology was applied to evaluate the effect of purge temperature, purge time, and sample weight on $\ell$ n (total peak area), breakthrough ratio, and peak area of perilla ketone the least volatile component of RPSO. Sample weight was the most important factor on the $\ell$ n (total peak area) but it did not affect peak area of perilla ketone. All process variables significantly influenced breakthrough ratio. The optimum condition was determined by superimposing contour plots at purge temperature of 48$^{\circ}C$ for 12 min purge time at sample weight of 0.60 g. 2-Propanone, 2-butanone, acetic acid, 2-methyl propanal were main breakthrough compounds in RPSO flavor.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.8
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• pp.334-340
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• 2006

Copper is widely used in electric wire, cable, conductor in electric devices. As the demand for electric power is increasing rapidly, electric power devices are getting amazingly bigger and complicated. The using of light-weight conductor can reduce the size and making cost of the electric devices. In high-frequency application, Electric current in a conductor tends to shift to the surface of the conductor, resulting in an uneven current distribution in the inner conductor. In the extreme case the current may essentially concentrate in the 'skin' of the inner conductor as a surface current. In high frequency application, therefore, inner area of copper conductor may replace with aluminum conductor, which reduces the weight of conductor. This paper describes the manufacture and evaluation of composite conductors made of copper and aluminum. The optimum extruding ratio was 16 at $300^{\circ}C$. The electrical resistance of manufactured composite bus bar was $57{\mu}{\Omega}$ at DC and $49.5{\mu}\{Omega}$ at 300Hz.