• Korean Journal of Soil Science and Fertilizer
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• v.26 no.4
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• pp.225-229
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• 1993

The objective of this research was to characterize the effect of ammonium thiosulfate(ATS) on soil urease activity and the influence of temperature and soil pH on inhibition of urea hydrolysis by ATS. The results obtained are summarized as follows. 1. Percent inhibition of urea hydrolysis ranged from 1.5~14.3% with 5% addition of ATS to urea to 7.6~20.5% with 10% inclusion at $25^{\circ}C$, which levels were lower than that of thiourea. 2. The effect of ATS on urease inhibition was greater in low temperature han high temperature. The addition of 10% ATS resulted in 62.6% and 41.7% inhibition of urea hydrolysis at $10^{\circ}C$ and $15^{\circ}C$, respectively. 3. The inhibitory effects of ATS were found rapidly or slowly at different soil pH. The inhibition of urease activity was showed after 24 hours at pH 6.0 and 6.5, while the hydrolysis of urea was inhibited by ATS after 48 hourse at pH 5.0, 7.0 and 7.5. Urea hydrolysis inhibitions after 72 hours incubation were similar at all pH tested. Therefore effects of ATS did not correlate with soil pH.

• Korean Journal of Weed Science
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• v.7 no.3
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• pp.257-264
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• 1987

Effect of various physical and chemical treatments on dark germination of Oenothera lamarckiana seeds were primarily investigated to find out factors affecting germination. Germination of seeds which did not germinate in the constant temperature and darkness was induced by several physical treatments such as sonification, wetting and drying, freezing and thawing, and removal of seed coat. Pretreatment of chilling ($4^{\circ}C$), freezing ($-10^{\circ}C$) and incubation at high temperature ($80^{\circ}C$) induced dark germination of seeds which did not germinate in the constant temperature ranges of 15 to $40^{\circ}C$ under darkness. Alternating temperature also had a stimulatory effect on dark germination of Oenothera lamarckiana seeds. Sensing of seeds to alternating temperature appeared to be completed during the first two days after imbibition. The minimum difference of temperature required for dark germination was $5^{\circ}C$ in the range of $15-25^{\circ}C$. A thiourea (1.0%) treatment induced dark germination, but GA, IAA, BA and Ethrel failed to do so.

• Korean Journal of Weed Science
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• v.18 no.4
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• pp.295-303
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• 1998

The seed dormancy is one of the peculiar characteristics of a number of weed species and it makes difficulties in weed control. To clarify the mechanism of seed dormancy, several chemicals such as $KNO_3$, KOH, thiourea, and $H_2O_2$ and phytohormone($GA_3$) were treated to dormant seeds. Among the species treated with several chemicals, the germination percentages of Setaria glauca, Ambrosia trifida and Ranunculus sceleratus were increased with $KNO_3$ and those of S. glauca, R sceleratus were increased with thiourea. Hydrogen peroxide promoted the germination of Setaria viridis and S. glauca. Germination percentages of S. viridis, S. glauca and Cyperus saraguinolentus were increased with enzyme treatment using pectinase. GA treatment enhanced the geim.ination of Eleusine indica and R sceleratus but the other species were affected slightly. Especially. E. indica showed linearity in the relationship between germination percentage and GA concentration. So, It seemed that E. indica can be used as a bioassy material for GA. Considering the phenological habits of weed species, the seeds were buried under soil for long time(more than 1 month) over winter. When seeds were buried in soil, the degree of dormancy was drastically decreased. Especially, germination of seeds buried were increased under alternating temperature. The germination rates of Persicaria ssp. and Chenopodium ssp. were increased by 50% order alternating temperature after burial for seven weeks.

• Journal of the Mineralogical Society of Korea
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• v.27 no.3
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• pp.115-124
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• 2014

In order to leach Au and Ag from gold-silver bearing sulfide concentrate, the sulfide concentrate was ground in a ball mill for a dry pre-treatment and a wet pre-treatment process. Mineralogical studies and thiourea leaching experiments were carried out with the pre-treated sulfide concentrate. The results of the pre-treatment with the concentrate samples showed the mean particle size and iso-electrical potential was smaller in the dry pre-treatment sample than in the concentrate sample, and the contents was lower in the wet pre-treatment sample than in the dry pre-treatment sample. In XRD analysis, amorphous properties were only shown in the wet pretreatment sample. The results of the concentrate sample leaching experiments showed that the best Au, Ag leaching parameters were when the addition of thiourea was at a 1.0 g concentration, ferric sulfate was 1.0 M, sulfuric acid was 2.0 M and the leaching temperature was at $60^{\circ}C$. The Au, Ag leaching rate was always much greater and faster with the wet pre-treatment samples than with the dry pre-treatment samples. Accordingly, it is expected that more Au, Ag can be leached in an eco-friendly methodology using wet pre-treatment. The pre-treatment could be improved with an optimized grinding additive reagent and through researching grinding time in future non-cyanide processes.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1195-1200
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• 2011

The catalytic enantioselective Mannich-type reaction promoted by chiral binaphthyl-modified bifunctional organocatalysts is described. The treatment of ${\alpha}$-fluoro-${\beta}$-ketoesters with N-Boc imines under mild reaction conditions afforded the corresponding ${\beta}$-aminated ${\alpha}$-fluoro-${\beta}$-ketoesters with excellent enantioselectivities (up to 98% ee).

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.331-335
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• 1999

Electroless plating nickel has superior mechanical property to electroplated nickel. Furthermore nickel can be coated on nonconducting substrate. In this research, electroless plating of nickel were conducted in different bath condition to find optimum conditions of electroless nickel plating for MEMS applications. The selectivity of activation method on several substrates was investigated. The effects of nickel concentration, reducing agent concentration and inhibitor on deposition rate were investigated. The effect of pH on deposition rate and content of phosphorous in deposited nickel was also investigated.

• Bulletin of the Korean Chemical Society
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• v.4 no.5
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• pp.217-219
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• 1983

A precise EDTA titrimetric method involving a weight titration of major portion with solid reagent followed by titration of the remainder with a very dilute standard solution has been developed for the determination of bismuth. When the end point is determined by means of amperometry with a rotating mercury electrode, the error in bismuth analysis is less than 0.01 % even when $Pb^{2+}$, $Zn^{2+}$, or $Cd^{2+}$ is present. However, copper interferes appreciably and masking with thiourea gives too low results.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.130.1-130.1
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• 2003

The metabolism of a novel anticancer agent 1-{3- [3-(4-Cyano -benzyl)-3H-imidazol-4-yl]-propyl }-3-(6-methoxy-pyridin-3-yl)-1-(2-trifluoromethyl-benzyl)-thiourea (YH3945) were investigated in the Sprague-Dawley rat after single oral and i.v. administration of [14C]-YH3945. Bile, feces, urine and plasma were collected and analyzed by an HPLC system equipped with multiple detectors. (omitted)

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.356.2-356.2
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• 2002

The structure of 1-phenyl-2-substituted thiourea derivatives have been studied and optimized for their cytotoxic activity. The three dimensional quantitative structure activity relationship (3D-QSAR) was investigated using comparative molecular field analysis (CoMFA). The result suggested that electrostatic and steric factors of 2-alkylureido-1-phenyl propanol derivatives were correlated well with cytotoxic activity. (omitted)

• Archives of Pharmacal Research
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• v.15 no.1
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• pp.104-108
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• 1992

2, 3-Diphenyl-6-formyl-5-methoxyindole reacts with ethyl cyano acetate to yield the arylidene derivative which forms with urea and thiourea the corresponding pyrimidine derivatives. The arylidene derivatives react with hydrazines and with active methylenes to form the respective pyrazole derivatives and the $\alpha, \;\beta$-disubstituted acrylonitriles. Seven new compounds were tested for their effects on the arterial blood pressure of rats and analgesic activity.