• Korean Journal of Soil Science and Fertilizer
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• v.31 no.3
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• pp.271-276
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• 1998

This experiment was carried out to investigate the changes on nutrient uptake and yields of onion when it was applied with urea and ammonium sulfate as nitrogen fertilizer types; potassium chloride and potasssium sulfate as potassium fertilizer types and lime requirement and phosphorus absorption coefficient controlled 5% as soil improvement index. The variety of onion used was CheonJuHwang and the soil used was Yonggye series in the Jeonnam Muan area. The amounts of N, P and K uptake were higher in the mixed application plot of ammonium sulfate and potassium sulfate than in the plot of urea or potassium chloride. The sulfate content of soil was higher in the period of plant growth than in the harvest stage. The sulfate content of plant was highest in the harvest stage and this content was higher in the stem and in the leaf than in the bulb. The sugar content of onion was 7.43~8.23 Brix content was higher in the large bulb than in the small bulb. The weight of dry matter and the rate of good quality were high in the mixed application plot of ammonium sulfate and potassium sulfate, so the yield of onion was increased 2~6% compared with control.

• Resources Recycling
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• v.29 no.2
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• pp.69-77
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• 2020

With rapid increasing production and installation, recycling of photovoltaic modules has become the main issue. According to the research, the accumulation of waste modules will reach to 8600 tons in 2030. Moreover, Crystalline-silicon (c-Si) Photovoltaic modules account for more than 90% of the waste. C-Si PV modules contain 1.3% of weight of photovoltaic ribbon inside which contains the most of lead, tin and copper in the PV modules, which would cause environmental and humility problem. This study provided a valuable metal separation process for PV ribbons. Ribbons content 82.1% of Cu, 8.9% of Sn, 5.2% of Pb, and 3.1% of Ag. All of them were leached by 3M of hydrochloric acid in the optimal condition. Ag was halogenated to AgCl and precipitated. Cu ion was extracted and separated from Pb and Sn by Lix984N then stripped by 3M H2SO4. The effect of the optimal parameters of extraction was also studied in this essay. The maximum extraction efficiency of Cu ion was 99.64%. The separation condition of Pb and Sn were obtained by adjusting the pH value to 4 thought ammonia to precipitate and separate Pb and Sn. The recovery of Pb and Sn can reach 99%.

• Fire Science and Engineering
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• v.32 no.3
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• pp.88-94
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• 2018

Fingerprints deposited on paper found at a fire scene are important evidence for determining a suspect's identity. On the other hand, because the temperature at the fire scene is very high, there are many difficulties in developing fingerprints. This study compared the effectiveness of ninhydrin, DFO, and silver nitrate to develop fingerprints deposited on paper exposed to high temperatures. Using a dry heat press, heat was applied to the paper at $200^{\circ}C$ for various times. Silver nitrate was found to be superior to the others under all conditions. Ninhydrin developed fingerprints weakly compared to DFO and silver nitrate. In addition, the sensitivity of DFO decreased with increasing exposure time. Therefore, it is recommended silver nitrate be used to develop fingerprints deposited on paper found at a fire scene.

• Journal of the Korean Chemical Society
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• v.44 no.1
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• pp.17-23
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• 2000

Electrodes of the polycationic film with electropolymerized $[Ru(v-bpy)_3]^{2+}$ having about 1:1 ratio of $PF6^-/ClO_4^-$as the doped counter ions, were modified with xylenol orange and diethylditbiocarbamate by ion exchange which had stability constant as 38.6 and 17.5 respectively. These electrodes were employed in the quantitative multiple determination of U(W) in solution. The working electrode of electrochemical cell for the analytical signal was Pt/p-$[Ru(v-bpy)_3]^{2+}$, ligand, U(VI) with Ag/AgCl reference elecrode. In the stripping voltammetry. electrode process was electron transfer controlled one and calibration curves at the ranges of $1.0{\times}10^{-3}{\sim}1.0{\times}10^{-7}$ M had excellent relationship as 0.99 and relative standard deviation as 5${\sim}$8%.

• Journal of the Korean Chemical Society
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• v.25 no.1
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• pp.7-12
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• 1981

Solvolysis of $p-CH_3, p-H, p-Cl and p-NO_2$-benzenesulfonyl chlorides have heen studied in MeOH-MeCN mixtures. A nonlinear Hammett plot with a ratio order of p-NO_2 > p-CH_3 > p-H > p-Cl was obtained; the reaction was thought to proceed by an S_N1-S_N2 borderline mechanism. In all cases the reactivity was a maximum at 90∼95%(v) methanol, whereas methanol monomer selectivity defined as fi = \frac{k1}{ki}i (k1; observed pseudo-first order rate constant: ki; hypothetical rate constant for MeOH solution having the same polymer structure as in the pure MeOH) was a maximum at 80% methanol with a decreasing order of fi as p-NO_2 > p-Cl > p-H > p-CH_3.$ This was interpreted as the decrease in tightness of transition state; the larger the fi, the tighter is the MeOH attached to the substrate, and hence the more susceptible the substrate becomes to the approaching monomer methanol.

• Resources Recycling
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• v.17 no.3
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• pp.29-34
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• 2008

Solvent extraction behaviors of iron(III) from chloride solution at high ionic strength condition between Alamine336 and TBP were compared by using MaCabe-Thiele diagram. Extraction isotherms of iron by the two extractants were obtained by calculating the equilibrium concentrations of iron in both phases from the initial extraction conditions. In calculating the equilibrium concentration of iron, chemical equilibria in the aqueous phase and mass balance together with the solvent extraction reaction were considered. MaCabe-Thiele diagram of iron by 1M Alamine336 indicated that two extraction stages could lead to complete extraction of 0.5M iron from 3M HCl solution at an A/O ratio of 6/5. The extraction power of 1M Alamine336 was found to be the same as 2-3M TBP. MaCabe-Thiele diagram together with the physical properties of the two extractants indicated that Alamine336 is superior to TBP in extracting ferric iron from chloride solution.

• Journal of the Korean Chemical Society
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• v.37 no.8
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• pp.695-701
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• 1993

Rate constants of solvolysis of 2-thiophenesulfonyl chloride were determined in aqueous binary mixtures with methanol, ethanol, acetone in water and in methanol. These data are interpreted using the equation of Grunwald-Winstein and Kivinen relationship. Also, kinetic solvent isotope effects in water and in methanol and product selectivities in alcohol-water mixtures were determined. Kinetic solvent isotope effect for hydrolysis of 2-thiopenesulfonyl chloride was 2.24 and 1.47 for methanol and water, respectively. Selectivity values for formation of ester relative to acid in ethanol-water mixtures show maximum S value. From kinetic solvent isotope effect in methanol and water, selectivity data in aqueous alcoholic solvents and solvent effects, it is proposed that the reaction channel favoured in low polarity solvents is general-base catalysis and/or is possibly addition elimination (S$_A$N) reaction pathway and in high polarity solvents iS S$_N$2 reaction mechanism.

• Journal of the Korean Chemical Society
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• v.65 no.4
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• pp.260-267
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• 2021

Increasing the needs for eco-friendly natural materials, much attention on natural dyes has been attracted. Curcumin, one of abundant natural dyes available in nature, is an eco-friendly molecule found in turmeric. In this study, the colorimetric sensing behavior characteristics of ammonia and hydrogen chloride gases was analyzed using curcumin ink-printed paper and cotton fabric by inkjet printing method. The fabricated paper and fabric were utilized as a colorimetric sensor that can track food spoilage. The color changes of the samples printed on the paper and cotton upon exposure to the toxic gases, the reversibility of the color changes, and the water resistance were investigated. Both samples showed reversible reactions with NH3 and HCl, and small amount of ammonia produced by food spoilage was successfully sensed with naked eyes, confirming its capability to warn food spoilage in our daily life.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2002.04a
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• pp.66-69
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• 2002

온실의 피복자재는 소재에 따라 분진의 오염정도가 다르다. 또한 세척을 하는 방법도 소재의 특성에 따라 다르게 하여야 한다. 즉 폴리에틸렌이나 염화비닐과 같은 플라스틱 필름 종류는 강산이나 강염기의 특성을 가진 세척제나 염소와 황이 포함된 유기인제를 포함한 세척제를 사용할 경우 내구성이 급격히 떨어져 파손의 우려가 있을 뿐만 아니라 토양오염의 원인이 되기도 한다. 반면에 인력이 많이 소모되는 손세척방법은 농가에서 쉽게 이용하기가 곤란하다. (중략)

• Journal of Environmental Health Sciences
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• v.9 no.1
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• pp.63-76
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• 1983

중금속은 해수에서보다 해수중의 생물계에 그 농도가 더 높은 것으로 알려져 있으며 수은도 무기형으로 생물계에 존재하다가 생물활동으로 인해 알킬형으로 변한다. food chain이 미량금속 축적의 주통로로 알려져 있으나 그외 몇가지 방법이 제시되고 잇다. 특히 연체동물은 미량금속의 축적현상이 온도, 폭로시간, 시간, 생리적 활동에 다라 상당히 달라진다. 또한 유기알킬 수은이 무기수은보다 비교적 낮은 독성을 나타내지만 후자의 피해도 무시할 수는 없다. 굴(crassostrea virginica)은 염화수은농도가 비교적 낮은 상태에서도 상\ulcorner량의 축적현상을 보여주었다. 두개의 compartment system을 연계적인 상태에서 보면 첫 compartment에서의 초기축적은 가역적이었으나 둘째 Compartment에서 측정된 원실율로 보아 비가역적 축적이상을 확인해 주었다. 뿐만 아니라 미량금속이 아가미와 외부 근육에서 가장 높은 축적률을 보인것은 flow system의 regression moder과 매우 흡사함을 암시하며 농도가 낮은 상태에서의 축적이상에 중요한 의미를 부여하였다.