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        검색결과 21

        2.
        2022.05 구독 인증기관·개인회원 무료
        Complexation of actinides and lanthanides with carboxylic organic ligands is known to facilitate migration of radionuclides from deep geological disposal systems of spent nuclear fuel. In order to examine the ligand-dependent structures of trivalent actinides and lanthanides, a series of Eu(III)-aliphatic dicarboxylate compounds, Eu2(oxalate)3(H2O)6, Eu2(malonate)3(H2O)6, and Eu2(succinate)3(H2O)2, were synthesized and characterized by using X-ray crystallography and time-resolved laser fluorescence spectroscopy. Powder X-ray diffraction results captured the transition of the coordination modes of aliphatic dicarboxylate ligands from side-on to end-on binding as the carbon chain length increases. This transition is illustrated in malonate bindings involving a combination of side-on and end-on modes. Strongly enhanced luminescence of these solid compounds, especially on the hypersensitive peak, indicates a low site symmetry of these solid compounds. Luminescence lifetimes of the compounds were measured to be increased, which is ascribed to the displacement of water molecules in the innersphere of Eu center upon bindings of the organic ligands. The numbers of remaining bound water molecules estimated from the increased luminescence lifetimes were in good agreement with crystal structures. The excitation-emission matrix spectra of these crystalline polymers suggest that oxalate ligands promote the sensitized luminescence of Eu(III), especially in the UV region. In the case of malonate and succinate ligands, charge transfer occurs in the opposite direction from Eu(III) to the ligands under UV excitation, resulting in weaker luminescence.
        4.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper examines a simple one-step and catalyst-free method for synthesizing carbon nanoparticles from aliphatic alcohols and n-hexane with linear molecule formations by using a stable solution plasma process with a bipolar pulse and an external resistor. When the external resistor is adopted, it is observed that the current spikes are dramatically decreased, which induced production of a more stable discharge. Six aliphatic linear alcohols (methanol- hexanol) containing carbon with oxygen sources are studied as possible precursors for the massive production of carbon nanoparticles. Additional study is also carried out with the use of n-hexane containing many carbons without an oxygen source in order to enhance the formation of carbon nanoparticles and to eliminate unwanted oxygen effects. The obtained carbon nanoparticles are characterized with field emission-scanning electron microscopy, energy dispersive X-ray spectroscopy, and Raman spectroscopy. The results show that with increasing carbon ratios in alcohol content, the synthesis rate of carbon nanoparticles is increased, whereas the size of the carbon nanoparticles is decreased. Moreover, the degree of graphitization of the carbon nanoparticles synthesized from 1-hexanol and n-hexane with a high carbon (C)/oxygen (O) ratio and low or no oxygen is observed to be greater than that of the carbon nanoparticles synthesized from the corresponding materials with a low C/O ratio.
        4,000원
        5.
        2015.05 구독 인증기관·개인회원 무료
        분리막을 이용한 투과증발법은 에너지 소모가 적고 경제적이며 환경친화적이기 때문에 분자스케일 액체/액체 분리에 있어서 매우 주목 받고 있는 기술이다. 방향족 화합물과 지방족 화합물을 분리하는 공정은 석유정제, 석유화학공정 등에서 특히 중요한 분리공정 중의 하나이다. 본 연구에서는 벤젠에 대한 고선택성을 나타내는 PEG가 함유된 폴리이미드 공중합체를 합성하였고, 1H-NMR 스펙트럼과 FT-IR 스펙트럼에서 PEG 특성 피크의 확인을 통하여 PEG가 도입되었음을 확인 하였다. 혼합물 분리를 위한 투과증발 실험 장치를 제작하여 PEG 함량이 다른 막을 제조하여 벤젠 조성 변화에 따른 투과증발 실험을 실시하였으며, 그에 따른 투과유량 및 투과도를 계산하여 투과특성을 확인하였다.
        6.
        2015.05 구독 인증기관·개인회원 무료
        연료로부터 벤젠 또는 톨루엔과 같은 유독한 방향족 성분의 제거 및 분리는 최대 허용 농도의 감소로 인해 점점 더 많이 주목 받고 있다. 그 중에서도 가솔린의 벤젠 함량은 지금 법률상으로 유럽에서 1% 이하로 제한되고 있다. 이러한 분리공정에 있어서 에너지의 소모를 줄이고 분리효율을 높일 수 있는 투과증발 공정이 각광을 받고 있다. 본 연구에서는 벤젠에 대한 고선택성을 나타내는 sulfonated SEBS 공중합체를 합성하였고, 1H-NMR과 FT-IR 분석을 통해 술폰화가 되었음을 확인 하였다. 혼합물 분리를 위한 투과증발 실험 장치를 제작하여 sulfonated SEBS막을 제조하여 벤젠 조성 변화에 따른 투과증발 실험을 실시하였으며, 그에 따른 투과유량 및 투과도를 계산하여 투과특성을 확인하였다.
        7.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        폴리이미드 기체 분리막의 기체 분리 성능을 향상시키기 위해서 2,3,5,6-Tetramethyl-1,4-phenylenediamine (TMPD) 구조를 지닌 폴리이미드를 1,2-Diaminoethane (DAE)과 1,6-Diaminohexane (DAH)으로 가교시켜 분리막을 제조하였다. Fourier transform infrared spectroscopy (FT-IR)를 이용해 가교 후 이미드 고리가 아미드 그룹으로 전환됨을 확인하였다.폴리이미드의 열분해 온도는 가교 후 감소하였으며, 이는 가교제의 알킬기 분해 때문이다. 가교된 폴리이미드 분리막의 d-spacing은 가교 시간이 증가함에 따라 감소하였다. 가교 후 CH4, N2, O2, CO2 기체의 투과도는 가교 전 보다 감소하였으며,DAH로 가교된 분리막이 DAE보다 더 높은 투과도를 나타냈다. 투과도와 달리 CO2/CH4, CO2/N2, O2/N2 기체 선택도 모두 가교 시간이 길어질수록 증가된 결과가 나타났다. CO2/CH4 기체의 선택도는 DAE로 6분 가교 시 최대 증가치를 나타냈으며 39.5%까지 증가하였다. O2/N2 선택도 또한 DAE로 6분 가교 시 최대 증가치를 가지며 20.5%까지 증가하였다. 이를 통해서DAE가 DAH보다 선택도 증가에 적합한 가교제임을 예상할 수 있으며 이와 달리 CO2/N2 선택도는 DAE로 3분 가교 시 감소해 CO2/N2 분리에는 적합하지 않은 결과가 나타났다.
        4,000원
        8.
        2012.10 구독 인증기관·개인회원 무료
        The pinewood nematode, Bursaphelenchus xylophilus is a serious forest pathogen in many countries including Japan, China and Korea. To minimize the environmental problems caused by synthetic chemicals broadly utilized in the control of B. xylophilus, we estimated the nematicidal potency of 63 aliphatic compounds against B. xylophilus by measuring their inhibition activity against acetylcholinesterases (ACE, EC 3.1.1.7) of B. xylophilus (BxACEs). In the primary inhibition assay using B. xylophilus crude protein, C6, C9, C10 2E-alkenal C12 alkanoic acid were observed the > 45% BxACE inhibition rate and they were subsequently estimated the inhibition rate against three recombinant BxACEs. Whole compounds showed the high inhibition rate against BxACE-1 and BxACE-2. Interestingly, C6 2E-alkenal and C12 alkanoic acid exhibited the high inhibition rate against BxACE-3 which would be insensitive to ACE inhibitors.
        9.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polyurethane adhesive is used in various fields as flexible packaging materials including a food packaging field. Therefore, the purpose of this study is synthesis of polyurethane adhesive which uses aliphatic isocyanate, and compares with aromatic isocyanate. The isocyanates for this test are toluene-2,4-diisocyanate(TDI), hexamethylene diisocyanate(HDI), 4,4-dicyclohexyl ethane diisocyanate(H12MDI), and isophorone diisocyanate(IPDI). And, the effect of any other diisocyanate are evaluated by several methods as for curing rate test, accelerate weathering test, and peel strength test. The polyurethane adhesive using curing catalyst and HDI has adhesion strength of about 560 g/15 mm between aluminium foil and nylon, about 1,520 g/15 mm between nylon and CPP. Those parameters are similar to polyurethane adhesive with TDI. Also, in case of curing rate, those are similar to TDI type polyurethane adhesive. Moreover, data of δE as color variation by QUV tester is equal to 4.12, as 48% against those of TDI type.
        4,000원
        10.
        2009.05 구독 인증기관·개인회원 무료
        Nematicidal activity of aliphatic compounds was tested against pien wood nematode, Bursaphelenchus xylophilus. There was a significant difference in nematicidal activity among function groups. In a test with alkanols and 2-alkenols, compounds with C8-C11 chain length showed 100% nematicidal activity at 0.5 mg/mL concentration. C6-C10 2-alkenals exhibited >95% nematicidal activity, but the other compounds with C11-C14 chain length showed weak activity. Nematicidal activity of alkanoic acids with C7-C11 chain length was strong. Whole compounds belonging to hydrocarbons, alkanals and alkanoic acetate showed weak nematicidal activity at 0.5 mg/mL concentration. Nematicidal activity of compounds which showed strong nematicidal activity at 0.5 mg/mL concentration was tested at a lower concentration. At 0.25 mg/mL concentration, whole compounds except C8 alkanol, C8 2-alkenol and C7 alkanoic acid showed >80% nematicidal activity. C9-C11 alkanols, C10-C11 2-alkenols, C8-C9 2-alkenals and C9-C10 alkanoic acids showed >80% nematicidal activity at 0.125 mg/mL concentration. Only C11 alkanol exhibited strong nematicidal activity at 0.0625 mg/mL concentration
        11.
        2007.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was aimed not only to develop the gill net and trap made of biodegradable monofilaments in order to prevent a ghost fishing and to protect marine ecosystem, but also to analyze their spinning process and physical properties. Results showed that the spinning speed of biodegradable polybutylene succinate(PBS) monofilament was estimated to be approximately 100m/min when spinning temperature and cooling water temperature were adjusted at 180℃ and 3℃, respectively. The breaking loads of PBS monofilaments were estimated to be 35.3kg/mm2 at Φ0.2mm, 46.5kg/mm2 at Φ0.3mm, and 49.7kg/mm2 at Φ0.4mm in the dry condition, respectively. However, its breaking loads in the wet condition were reduced by 2.4-5.5%, compared to those in the dry condition. The knotted strength of PBS monofilament at Φ0.2mm was estimated to be 98.6% of PE in the dry condition. The breaking load of PBS monofilament at Φ0.3mm was evaluated to be 81.8% of PA, and its softness showed 3 times less than that of PA in the wet condition. The breaking load of PBS monofilament at Φ0.4mm was 95.3% of PA, and its softness showed 1.6 times less than that of PA in the wet state. However, the load elastic elongations of two kinds of monofilaments were estimated to be 1% higher than that of PA.
        4,000원
        12.
        2002.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Two PU flame-retardant coatings, 2,3-DBPO/N-l00 (DBPON) and 2,3-DBPO/IL (DBPOI), were prepared by curing 2,3-dibromo modified polyester (2,3-DBPO) with isocyanate curing agent Desmodur N-l00 (or Desmodur IL) at room temperature. The physical properties and flame-retardancy of the two coatings were tested and compared. As a result, the pot-life, yellowness index, lightness index difference, 60˚ specular gloss, cross-hatch adhesion, viscosity, and accelerated weathering resistance of DBPON were better than those of DBPOI; the fineness of grind of the two coatings were the same; and the drying time, hardness, and abrasion resistance of DBPOI were better than those of DBPON. The flame retardancy of the flame-retardant coatings increased with the content of the flame retarding component, 2,3-dibromopropanoic acid (2,3-DBP); and the LOI values of the two coatings were in a range of 27~29% when the content of 2,3-DBP was 30wt%.
        4,000원
        14.
        1999.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        소포제의 주성분으로 소수성 알킬기 탄산수가 12에서 18까지의 고급지방알코올, 고급지방산, 고급지방산에스테르를 사용하였다. 제조한 소포제의 입도분포, 온도, 농도에 대한 소포 특성을 1L/min의 유속하의 ASTM 방식의 Air Injection Method로 측정하였고, 표면장력과 유화력을 측정하였다. 이들 소포제의 입도분포에 대한 소포특성은 입도분포가 5.5~6.8μm 범위인 소포제 조성물이 우수한 소포제 특성을 보였다. 묽은 수용액상에서 소포제의 표면장력은 농도가 10-2wt%에서 33~34 mN/m 범위였고, 고급 지방산 알코올을 사용한 소포제 조성물의 유화력이 우수하였다.
        4,000원
        15.
        1994.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        MDABM and MDAEW, as a accelerating weight loss agents, were prepared by adding water to myristyldimethylbenzylammonium bromide(MDAB) and myristyldimethylethylammonium ethyl sulfate (MDAE) synthesized. As a result of weight loss finishing of the MDABW and MDAEW with NaOH on PET fiber, the ratio of weight loss of MDABW was very larger than that of MDAEW. This result showed that quaternary ammonium bromide had higher weight loss effect than quaternary ammonium sulfate, and the ratio of weight loss was greatly varied with the kind of quaternary ammonium salts used. In these conditions, proper treatment concentration, treatment time, and treatment bath ratio were about 8g/l, 6O~90min, and 40:1~50:1, respectively.
        4,000원
        16.
        1991.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The reactions of semicarbazide hydrochloride with aliphatic and alicyclic ketones were studied kinetically at 15, 25, 35 and 45℃ in 20% ethanol solution buffered at pH 2.9. The rate of cyclohexanone semicarbazone formation is 5.5 times as fast as that of cyclopentanone semicarbazone, while 3-pentanone semicarbazone is 4.7 times as slow as that of 2-pentanone, The activation energy of cyclohexanone, 2-pentanone, 2 hexanone, cyclopentanone, 4-methyl-2-pentanone and 3-pentanone semicarbazone formation are calculated 5.08, 7.52, 8.79, 9.59, 9.49, 11.59, respectively. It is concluded from the effect of ionic strength that the reaction is affected by not ion but neutral molecules being progressed hydrogen bond between oxygen atom of carbonyl group and hydrogen atom of acid-catalyst and concerted nucleophilic attack of free base on the carbonly compound. Dependence on pH of the rate of 2-pentanone semicarbozone formation is linear relationship below pH 4.60 and above pH 5.60. As a result of studing citric acid catalysis, second order constants increase linearly with citric acid concentration. As the catalyst concentration is varied from 0.025 to 0.10 mol/1 at pH 2.90, the rate constants increase 1.4 times, but slight increase is observed at pH 5.60. Conclusively, the rate-determining step is formation of tetrahedral interemediate below pH 4.65 and dehydration between pH 5.60 and pH 7.11. It is concluded that the formation reaction of cyclohexanone semicarbazone is faster than cyclopentanone semicarbazone due to the steric strain in the process of forming tetrahedral intermediate.
        4,000원
        17.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        Glucosinolates (GSLs), beneficial secondary metabolites for human health are abundantly present in radish vegetable. Radish is a member of Brassicaceae family and its seed, leaf and root contain very important GSLs. The objective of this study was to determine the variation of individual and total GSL contents in leaves and roots of 44 radish (Raphanus spp.) germplasm (26 R. sativus L., 3 R. raphanistrum, and 15 R. sativus L. var. raphanistroides Makino), and compare the GSL contents between leaves and roots among three Raphanus species. Thirteen GSLs were identified, being the glucoraphasatin (GRS) and glucobrassicin (GBS) the most abundant aliphatic and indolyl GSLs in both the leaves and roots. Variation in individual and total GSL contents was found among the germplasm of three Raphanus species. The GRS content was higher in roots than that of leaves in all three Raphanus species but the GBS content was higher in leaves than roots. GRS was represented 87.0%, 92.7% and 94.7% of the total GSL in roots of R. sativus L., R. raphanistrum and R. sativus L. var. raphanistroides (Makino) germplasm, respectively. Germplasm of R. raphanistrum exhibited the highest (average, 79.5 μmol/g dw) total GSL with a ranged from 62.7 to 92.9 μmol/g dw. The germplasm IT119288, Joseonmu and IT119262 from R. sativus L., RA 504 and K046542 from R. raphanistrum, and Gyeongju-2003-32 (G2003-32) and IT302373 from R. sativus L. var. raphanistroides (Makino) had high total GSL contents and these could be good candidates for developing the functional compounds-rich varieties in radish breeding program.
        18.
        2014.07 서비스 종료(열람 제한)
        Glucosinolates (GLS) are secondary metabolites commonly occurring in Brassica crops and more than 130 different GLS have been reported in diverse plants. Recent studies have indicated that isothiocyanate (ITC) derived from GLS by hydrolysis had a potential for anticancer activity against several rumor cells on human. In addition, it was found that glucoraphenin (GRE) and glucoraphasatin (GRH) were abundant and differently regulated in radish plant, depending upon organs and developmental stages. Microspores isolated from flower buds of radish were cultured in vitro to obtain doubled haploid (DH; but homozygous) lines in a short time period. The present study was conducted to determine the concentration of GRE and GRH, an immediate precursor of ITC from DH lines of radish plant. Total 41 DH lines were selected based on flow cytometry analysis. The seeds, obtained by bud pollination from the DH lines, were planted and 3-weeks-old young seedlings were used for the major aliphatic GLS analysis. Amounts of GRH were highly variable from the DH lines ranging from 2.3 to 31.5 mg·g-1 dry weight (DW). The donor plant (DP) contained 18.4 mg·g-1 DW. It was noticed that there were 6-fold differences in the amounts of GRE between the highest and lowest DH lines. Among 41 lines tested, 14 DH lines of radish plant were significantly reduced in the amount of sum of GRH and GRE compared those of the donor plant (P<0.05), whereas only three lines increased. The results obtained in the present study will lend to select genotypes with low and high GLS contents of radish plant. In addition, those DH lines will aid to elucidate a biosynthetic pathway of the aliphatic GLS in radish plant, which remain for the most part unsolved.
        19.
        2002.09 KCI 등재 서비스 종료(열람 제한)
        This study was performed : 1) to establish the experimental analysis conditions for the sorption and desorption of toxic organic contaminants to/from the activated sludge, sediment, and clay, and 2) to determine the sorption and desorption equilibrium coefficients of some representative halogenated aliphatic compounds. Through the preliminary sorption test using Azo dye, a setting of quantitative experimental conditions to determine the sorption and desorption characteristics was decided as follows; equilibration time of 180 minutes, centrifuge for 15 minutes at 5000×g, and 500㎎/ℓ of TOC concentration. The sorption and desorption characteristics of halogenated aliphatic compounds onto activated sludge, sediment and clay could be described very well using the Freundlich isotherm. The preference of the average sorption capacity of the overall compounds showed in the sequence sediment 0.26㎎/g, clay 0.23㎎/g, and activated sludge 0.11㎎/g. The desorption rate of the sorbed compounds onto activated sludge, sediment and clay was approximately 89.8%, 35.3%, and 66.4%, respectively.
        20.
        2002.07 KCI 등재 서비스 종료(열람 제한)
        Sorption and desorption is an important phenomenon to determine the fate of halogenated aliphatic hydrocarbons in the aqueous phase. This study was conducted to develope a predictive equation capable of estimating the sorption and desorption potentials of halogenated aliphatic hydrocarbons onto the sludge from activated process, sediment, and clay. It has shown that the sorption and desorption parameters can be accurately estimated using Quantitative Structural Activity Relationship(QSAR) models based on molecular connectivity indexes of test compounds. The QSAR model could be applied to predict the sorption and desorption capacity of the other halogenated aliphatic hydrocarbons. The QSAR modeling would provide a useful tool to predict the sorption and desorption capacity without time-consuming experiments.
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