• 한국염색가공학회지
• /
• 제6권1호
• /
• pp.1-7
• /
• 1994

A low-temperature dyeing system for silk fabrics based on a redox system has been investigated. Some factors affecting dyeing of silk fabrics with levelling acid dyes in the absence and presence of certain redox system were investigated under different conditions. The variables studied were; type and concentration of redox system, dyeing conditions, i. e. temperature and time, dye concentration, material-to-liquor ration(LR) and colour fastness. The colour strength(K/S value) is outstandingly higher in the presence than in the absence of redox system. A comparison between the colour strength values of such dyeings abtained the three redox system would call for the following order ; Glyoxal/hydrogen peroxide>thiourea/hydrogen peroxide>glucose/hydrgen peroxide> nothing. In the presence of redox system, free radicals are supposed to be formed in both the fiber and the dye and the interaction between these free radicals bring about covalent fixation beside the usual electrostatic bonds, hydrogen bonds and Van der Waals forces.

• 분석과학
• /
• 제14권6호
• /
• pp.530-534
• /
• 2001

Effect of stripping solutions on the Duolite GT-73 chelating resin for ten elements, Ag(I), Al(III), Ca(II), Cd(II), Cu(II), Fe(II), Hg(II), Mn(II), Pb(II), and Zn(II), was investigated. Relation between affinities of the metal ions and solubility products of metal sulfides was studied. The smaller the solubility product of metal sulfideis, the larger the affinitie with the ionsis. The ions which have the solubility products larger than $10^{-23}$ could be effectively desorbed with nitric acid. Complexation with chloride ion enhanced the desorption efficiencies of the ions having moderately strong affinity with the resin. The ions which have very strong affinity by the chelating resin can be desorbed by complextion with thiourea and hydrochloric acid.

• 한국표면공학회지
• /
• 제38권3호
• /
• pp.112-117
• /
• 2005

In this paper, CdS thin films, which were widely used as a window layer of the CdS/CdTe and the $CdS/CuInSe_2$heterojunction solar cell, were grown by chemical bath deposition, and the structural, optical and electrical properties of the films on reaction temperatures were investigated. Cadmium acetate and thiourea were used as cadmium and sulfur source, respectively. And Ammonium acetate was used as the buffer solution. As the reaction temperatures were increased, the deposition rate of CdS fllms prepared by CBD was increased and the grain size was large due to increasing reaction rate in solution, also optical transmittance of the films in visible lights was increased on rising reaction temperatures.

• Journal of Industrial and Engineering Chemistry
• /
• 제68권
• /
• pp.33-41
• /
• 2018

The manuscript reports synthesis of exceptionally stable gold nanoparticles (GNPs) using Momordica charantia fruit extract. The synthesis approach was optimized by refining three experimental variables including source of the fruit extract (peel, seed, and seed coat), pH of the solution, and temperature of the reaction medium. As synthesized GNPs showed excellent stability against various thiolated compounds (e.g., thioglycolic acid, thiourea, ${\text\tiny{L}}-cystine$, 1-dodecanethiol, and cysteamine hydrochloride). Moreover, these nanoparticles showed distinctive colorimetric responses against $Cd^{2+}$ and thiophenol (TP) from their potential interferences. The limit of detection (LOD) values for $Cd^{2+}$ and TP were determined as 0.186 and $0.154{\mu}M$, respectively.

• Bulletin of the Korean Chemical Society
• /
• 제20권7호
• /
• pp.819-823
• /
• 1999

Antioxidant activities of various mushroom fruiting bodies were investigated in vitro. Among the mushroom extracts examined, Armillariella mellea, Daedalea dickinsi, Fomitella fraxinea and Pleurotus cornusopiae markedly exhibited inhibition on lipid peroxidaton of rat liver microsomes. Ergosterol peroxide (5,8-epidioxy-5α,8α-ergosta-6,22E-dien-3β-ol), antioxidant from A. mellea, was isolated by solvent extraction, silica gel column chromatography and recrystallization. The structure of the compound was determined by NMR, GC/MS and X-ray crystallography. Ergosterol peroxide showed potent inhibition on lipid peroxidation and exhibited higher antioxidant activity than well-known antioxidants, α-tocopherol and thiourea.

• Bulletin of the Korean Chemical Society
• /
• 제17권3호
• /
• pp.228-234
• /
• 1996

The rates of solvolysis of 1-(4-methoxyphenyl)-1-aryl-2,2,2-trifluoroethyl chlorides[I] in a variety of solvents were measured by an electroconductometric method. LArSR relationships (Yukawa-Tsuno eq.)were found to give a linear plot, log(k/ko)=-1.84[σo+0.918(σ+-σo)], in 80% aqueous ethanol. Small |ρ| and r values in comparison with 1-aryl-1-(trifluoromethyl)ethyl tosylate(ρ=-6.09, r=1.59) suggested that the carbocationic charge in the transition state was dispersed by a strong p-π donor, p-methoxy group. Linear mY plots with m 0.90 for all of the substituents in aqueous acetone and m=0.60-0.82 for those of aqueous ethanol indicate that this solvolysis proceeds via an SN1 mechanism with nucleophilic solvent assistance. Thiourea effects and isokinetic temperatures for the rate of solvolysis also can prove the above mechanism.

• Bulletin of the Korean Chemical Society
• /
• 제5권5호
• /
• pp.175-178
• /
• 1984

Two series of membranes have been prepared by postcrosslinking highly syndiotactic and isotactic poly (2-hydroxyethyl methacrylate), P(HEMA). The crosslinker used was hexamethylene diisocyante (HMDIC). The distribution coefficients (K$_{D2}$) of the model solutes such as urea (and thiourea), their derivatives, homologous alcohol series and amide sreies in water-swollen tactic P(HEMA) membranes at $25^{\circ}C$ were mesaured. In addition, the concentration effects of acetamide and butyramid were also measured. On the basis of hydrophobic interaction and the structural factors of tactic P(HEMA) membranes, the hydrophobic adsorption of the solutes in the polymer matrix were discussed. The results showed that the more hydrphobic the solute is, the higher the $K_{D2}$ value is. And the polymer conformation also affects the distribution of solvents.

• Archives of Pharmacal Research
• /
• 제12권3호
• /
• pp.181-185
• /
• 1989

When 3-acetyl coumarin derivatives are treated with bromine, 3-(w-bromoacetyl) coumarin derivatives are obtained. The reaction of 3-(w-bromoacetyl)coumarin derivatives with thiourea or with amines for two hours leads to the formation of 2-Amino-4-(3-coumarinyl) thiazole or 3-(w-aminoacetyl) coumarin derivatives, respectively. While 3-(w-bromoacetyl) coumarin derivatives react with amines for 5-8 hours to yield imino derivatives of 3-(w-aminoacetyl) coumarin. The antimicrobial activity of Ia-b, IIa-c, IVc-f, IVh and V$_{c}$, f, h, k, m, and q was studied.d.

• 한국식품과학회지
• /
• 제11권1호
• /
• pp.42-49
• /
• 1979

꽃잎맨드라미 anthocyanin을 식용색소(食用色素)로 이용할 목적으로 모델시스템하에서 anthocyanin 안정성(安定性)에 미치는 온도, pH, 당류(糖類) 및 그 분해산물(分解産物), ascorbic acid, quercetin, sodium pyrophosphate, thiouea 그리고 금속(金屬) 이온들의 영향을 조사한 결과는 다음과 같다. 1. pH가 8.0에서 1.0으로 낮아짐에 따라 anthocyanin의 파괴(破壞)가 지연되였는데 pH 2.0에서는 초기의 anthocyanin 파괴(破壞)가 pH 2.0, 3.0에서 보다 더 빨랐다. 2. 수용액내에서 가열 $(80^{\circ}C)$시 pH 2.0에서의 anthocyanin잔존량(殘存量)이 다른 pH수준에서보다 더 많았으며 저장온도가 상승함에 따라 색소(色素)의 파괴(破壞)가 크게 촉진되었는데 $40^{\circ}C$의 암소(暗笑)에서 10일후 19%정도 $2^{\circ}C$에서는 90%정도 남아 있었고 $2^{\circ}C$에서의 반감기(半減期)는 63일이었으나 $40^{\circ}C$에서는 1.7일로 떨어졌다. 이 색소파괴(色素破壞) 반응(反應)의 활성화(活性化)에너지는 18.93kcal/mole였다. 3. AA의 농도가 15 mg/100 ml에서 50 mg/100 ml로 증가함에 따라 반면에 색소잔존량(色素殘存量)은 줄어 들었다. 4. Anthocyanin의 파괴(破壞)에 대한 glucose와 fructose영향사이에 뚜렷한 차이가 없었으며 당류분해물(糖類分解物)중에서는 formic acid, levulinic acid, furfural 순으로 색소잔존율(色素殘存率)이 감소하였으며 furfural anthocyanin 파괴작용(破壞作用)이 가장 심하였다. 5. Ascorbic acid 공존하(共存下)에서 quercetin, sodium pyrophosphate 다같이 anthocyanin에 대한 보호작용을 인정할 수 없었으나 thiourea가 50 및 100 mg/100 ml인 처리구에서는 색소손실량(色素損失量)이 상당히 줄어 들었다. 6. 금속(金屬) 이온들중 $Hg^{2+}$과 $Cu^{2+}$은 30 ppm에서 기타 금속(金屬)이온들에 비하여 anthocyanin의 파괴(破壞)를 촉진시켰다.

• 폴리머
• /
• 제27권4호
• /
• pp.330-339
• /
• 2003

폴리(스티렌-co-디비닐벤젠) 수지 페닐고리의 클로로메틸화를 통해 메틸렌티올기를 도입한 수지 (I), 폴리(스티렌-co-메틸 메타아크릴레이트-co-디비닐벤젠) 공중합체의 페닐고리와 에스터기에 클로로메틸화 반응을 거쳐 각각 메틸렌티올기를 도입하여 중금속 이온들과의 배위결합에 필요한공간개념을 배려한 수지(II) 및 폴리(스티렌-co-디비닐벤젠) 수지의 페닐고리를 클로로설폰화한 후, 소디움하이드로술파이드로 티오설폰산화한 수지 (III) 등 3가지 종류의 티올계 구상형 수지들을 합성하였다. 이어, 이들 킬레이트 수지들에 대한 중금속 이온의 흡착경향을 평가한 결과, 티올기 함유 I형 킬레이트 수지는 Hg$^{2＋}$에 대해서만 선택적 흡착성을 보였고, 티올기 함유 II형 킬레이트 수지는 Hg$^{2＋}$에 대한 흡착성능이 보다 향상되었으며, Cu$^{2＋}$, Pb$^{2＋}$, C$d^{2＋}$ 및 Cr$^{3+}$ 등의 몇몇 중금속 이온들에 대해서도 약간의 흡착능을 보였다. 다른 한편으로, 친수성의 티오설폰산기 함유 III형 킬레이트 수지는 효율적 흡착체로서 Hg$^{2＋}$, Cu$^{2＋}$, Ni$^{2＋}$, Co$^{2＋}$ 및 Cr$^{3+}$ 등의 중금속 이온들은 물론, 특히 C$d^{2＋}$ 및 Pb$^{2＋}$에 높은 흡착능을 보였다.