• Title/Summary/Keyword: stabilizers

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The Effects of Stabilizers on Adhesion of Electroless Copper Deposits on Alumina (Alumina 소지상의 무전해 동도금층의 밀착력에 미치는 안정제의 영향)

  • 최순돈;이희록
    • Journal of the Korean institute of surface engineering
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    • v.29 no.2
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    • pp.109-119
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    • 1996
  • In order to improve adhesion of electroless copper deposits on alumina substrates, some stabilizers such as 2-Mercapto Benzothiazole, thiourea and NaCN were added over a wide range of concentrations. The adhesion tests of the deposits were performed by using the cellophane tape and the push-pull scale. With the minor addition of the stabilizers, 2-MBT having a large molecular size gives poor adhesion, together with a finer grain structure, whereas Thiourea and NaCN show a high mechanical strength of the deposits. The high mechanical strength is supposed to be due to the easy desorption of hydrogen gas generated from the electroless reactions. A large amount of the three stabilizers decreases the adhesion for all the cases, resulting from strong adsorption of the stabilizers to the substrates.

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Feasibility Test for Phytoremediation of Heavy Metals-Contaminated Soils using Various Stabilizers (중금속 오염토양에 대한 안정화 및 식물상 정화공법의 동시 적용연구)

  • Jeon, Jongwon;Bae, Bumhan;Kim, Younghun
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.3
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    • pp.59-70
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    • 2012
  • In this study, to select the best stabilizer for the heavy metals-contaminated soil from a smelter area during phytoremediation, a plant uptake experiment and a soil stabilization were simultaneously applied using Pteris multifida Poir. and five pre-screened stabilizers(zeolite, Mn dioxide, slag, Ca oxide, and magnetite). The extracted heavy metal was measured and compared using a 3 step sequential extraction for the soil samples. The growth rate of the plant was also evaluated. The stabilizers stabilized heavy metals in soil and reduced the extraction rate. Magnetite and calcium oxide showed better results than other stabilizers. The stabilizers enhanced the growth of the plant. All the heavy metals except for arsenic were concentrated in roots while arsenic was concentrated in leaves of the plant. It is concluded that the stabilizers can minimize the heavy metal release from the contaminated soil during phytoremediation and stimulated the growth of plant. These effects of stabilizers could compensate for some weak points of phytoremediation such as reaching of heavy metals by rainwater.

Analysis of Hypoxia-Inducible Factor Stabilizers by a Modified QuEChERS Extraction for Antidoping Analysis

  • Kim, Si Hyun;Lim, Nu Ri;Min, Hophil;Sung, Changmin;Oh, Han Bin;Kim, Ki Hun
    • Mass Spectrometry Letters
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    • v.11 no.4
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    • pp.118-124
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    • 2020
  • An analytical method was developed for hypoxia-inducible factor (HIF) stabilizers based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) sample preparation and liquid chromatography-high resolution mass spectrometry analysis. HIF stabilizers potentially enhance the performance of athletes, and hence, they have been prohibited. However, the analysis of urinary HIF stabilizers is not easy owing to their unique structure and characteristics. Hence, we developed the QuEChERS preparation technique for a complementary method and optimized the pH, volume of extraction solvent, and number of extractions. We found that double extraction with 1% of formic acid in acetonitrile provided the highest recovery of HIF stabilizers. Moreover, the composition of the mobile phase was also optimized for better separation of molidustat and IOX4. The developed method was validated in terms of its precision, detection limit, matrix effect, and recovery for ISO accreditation. To the best of our knowledge, this is the first demonstration of the application of the QuEChERS method, which is suitable as a complementary analytical method, in antidoping.

Aerodynamic stabilization of central stabilizers for box girder suspension bridges

  • Ge, Yaojun;Zou, Xiaojie;Yang, Yongxin
    • Wind and Structures
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    • v.12 no.4
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    • pp.285-298
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    • 2009
  • For long-span suspension bridges with their intrinsic limit in flutter, some counter measures, for example, central stabilizers, should be adopted to improve aerodynamic stability to meet with the appropriate wind resistance requirements. The present paper introduces aerodynamic stabilization for long-span suspension bridges with box girders by using central stabilizers based on Xihoumen Bridge with the main span of 1650 m. The aerodynamic stabilization study covers experimental investigation of sectional model testing, comprehensive evaluation of three central stabilizers and theoretical analysis of stabilizing mechanism related to flutter derivatives, aerodynamic damping and degree participation.

Degradation Behavior of Nylon 4 in the Presence of Newly Synthesized Thermal Stabilizers (합성 열안정제에 의한 나일론 4의 분해거동)

  • Jang, Geunseok;Kim, Jongho;Kim, Daigeun;Kim, Young Jun;Lee, Taek Seung
    • Polymer(Korea)
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    • v.38 no.3
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    • pp.314-319
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    • 2014
  • Three kinds of thermal stabilizers for nylon 4 were synthesized to incorporate both hindered amine groups and methylene units with various lengths. It is expected that the hindered amine groups play a role in the capture of degradation-triggering species. Considering sequence rules, hydrogen bonding formed between nylon 4 and the stabilizers is optimized to alter the lengths of the methylene units in the stabilizers. As a result, it was found that a tetramethylene unit in the stabilizer is an optimal length for hydrogen bonding in terms of isothermal thermogravimetric analysis (TGA). Considering the slight and often negligible improvement of thermal stability of nylon 4 containing commercially-available nylon 6 stabilizers, retardation of thermal degradation has been substantially improved upon.

Efficiency of Heavy Metal Stabilizers in Various Soils (토양 특성에 따른 중금속 안정화 효율 평가)

  • Kim, Young Hyun;Oh, Se Jin;Kum, Donghyuk;Shin, Minhwan;Kim, Dongjin;Lee, Sang Soo
    • Korean Journal of Environmental Agriculture
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    • v.40 no.3
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    • pp.231-238
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    • 2021
  • BACKGROUND: Metal contamination of farmlands nearby abandoned mines is a serious environmental problem. This study was conducted to evaluate the efficiency of stabilizers on different type of the soils contaminated with metals. METHODS AND RESULTS: The texture of silt loam soil initially contaminated with heavy metal was artificially adjusted to loam and sandy loam by adding sand, and the soil organic matter content (1.5%) was also altered by adding peat to the soils at 3.5 and 8.0%. The soils were mixed with 3% (w/w) of each limestone, dolomite, and steel slag. For the soils with different textures, the bioavailability of As was found to be the lowest in sandy loam compared to others metals such as Cu, Pb, and Zn. The efficacy of limestone and dolomite was not significantly different compared to the soils having different organic matter contents, but the stabilization efficiency of steel slag increased as the soil organic matter content increased. Moreover, stabilizers showed inhibition effect on the uptake of metals to plant. CONCLUSION: The stabilizers were found as effective materials to immobilize metals in soil and to decrease plant uptake of metals. Studies are needed to deeply elucidate the interaction between influencing factors and various stabilizers.

Changes of Rheological Properties of Yoghurt by Different Kinds Stabilizers (Yoghurt의 안정제 종류에 따른 물성 변화)

  • 최순호;장운기;정종국;오동규;이부웅
    • Food Science of Animal Resources
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    • v.18 no.1
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    • pp.35-41
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    • 1998
  • The objective of this study was to examine the changes of physical properties by additions of different kinds of stabilizers milk proteins concentration, when stored at 4$^{\circ}C$ or 20$^{\circ}C$ for yoghurt. the results were summarized as follows: 1. Addition of 2% carboxyl methyl cellulose and carrageenan, gelation 0.4%, pectin and starch 0.6%, and carrageenan & pectin 0.8% in the manufacture of yoghurt increased the viscosity, water-holding capacity and protein hydration of yoghurt. 2. Addition of 3% skim milk powder, Ca-caseinate or Na-caseinate 0.6% increased the viscosity, water-holding capacity and protein hydration of yoghurt. 3. Twenty five percent of evaporation of milk promoted to build up the optimal structure of the micelles of yoghurt and improved viscosity, water-holding capacity and protein hydration of yoghurt. 4. Addition of stabilizers to yoghurt showed an increase of viscosity, water-holding capacity and protein hydration when compared with non-addition of stabilizers to yoghurt at 4$^{\circ}C$, 20$^{\circ}C$ storage for 12hrs, 96hrs followed by the decrease of it.

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Effect of Chemical Stabilizers in Silver Nanoparticle Suspensions on Nanotoxicity

  • Bae, Eun-Joo;Park, Hee-Jin;Park, Jun-Su;Yoon, Je-Yong;Kim, Young-Hun;Choi, Kyung-Hee;Yi, Jong-Heop
    • Bulletin of the Korean Chemical Society
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    • v.32 no.2
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    • pp.613-619
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    • 2011
  • Colloidal silver nanoparticles (AgNPs) have been commercialized as the typically stabilized form via the addition of a variety of surfactants or polymers. Herein, to examine the effects of stabilizing AgNPs in suspension, we modified the surface of bare AgNPs with four type of surfactants (NaDDBS, SDS, TW80, CTAB) and polymers (PVP, PAA, PAH, CMC). The modified AgNPs was applied to compare suspension stability and nanotoxicity test using Escherichia coli (E. coli) as a model organism. Modification of AgNPs surface using chemical stabilizer may be not related with molecular weight, but chemical structure such as ionic state and functional group of stabilizer. In this study, it is noteworthy that AgNPs modified with a cationic stabilizer (CTAB, PAH) were importantly toxic to E. coli, rather than anionic stabilizers (NaDDBS, SDS). Comparing similar anionic stabilizer, i.e., NaDDBS and SDS, the result showed that lipophilicity of chemical structure can affect on E. coli, because NaDDBS, which contains a lipophilic benzene ring, accelerated the cytotoxicity of AgNPs. Interestingly, none of the stabilizers tested, including biocompatible nonionic stabilizers (i.e., TW80 and cellulose) caused a reduction in AgNP toxicity. This showed that toxicity of AgNPs cannot be reduced using stabilizers.

A Study on the Design-parameter of Mixed Ground by Using Cement-type Stabilizer (시멘트계 고화재에 의해 혼합처리된 지반의 설계정수에 관한 연구)

  • 천병식;임해식;전진규
    • Journal of the Korean Geotechnical Society
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    • v.16 no.2
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    • pp.79-89
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    • 2000
  • The application of stabilization method has increased because of short construction periods, no environmental problems with dumped and replaced soil, assurance of required strength and economical effect with mid to small size construction. The unconfined and triaxial(UU-condition) compression tests were executed with each mixing sample for the study of the improvement effects and the effect of design-parameters by the stabilization methods. Three typical stabilizers, which are representative in Korea, were applied in this study, and three common soils(very soft clay, general weathered soil, common clay), which are common in Korea, were used in this study. In this study, the effect of engineering factors(soils, stabilizers and water contents, etc.) which are important parameters for the improvement effects of mixed ground by stabilizers, was analyzed. As results, the tendencies of design-parameters(unconfined compression strength, deformation modulus and strength parameter) are presented and the criteria of the application of stabilization methods are suggested.

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Drug-Drug Interactions : Mood Stabilizers and Anti-Anxiety Drugs (약물상호작용 : 기분안정제와 항불안제)

  • Kim, Young Hoon;Rhee, Jung Goo
    • Korean Journal of Biological Psychiatry
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    • v.7 no.1
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    • pp.34-45
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    • 2000
  • Pharmacotherapy of bipolar disorder is a rapidly evolving field. Mood stabilizers and anticonvulsants have varying biochemical profiles which may predispose them to different adverse effects and drug-drug interactions. Several of the new anticonvulsants appear less likely to have the problems with drug-drug interaction. To provide more effective combination pharmacotherapies, clinicians should be allowed to anticipate and avoid pharmacokinetic and pharmacodynamic drug-drug interactions. We reviewed the role of cytochrome P450 isozymes in the metabolism of the drugs and their interactions. The drug-drug interactions of several classes of drugs which used as mood stabilizers and new anticonvulsants, some of which may have psychotropic profiles, are discussed mainly in this article. Finally, potential pharmacokinetic interactions between the benzodiazepines and other coadministered drugs are discussed briefly.

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