• Journal of the Korean Society of Industry Convergence
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• v.27 no.2_2
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• pp.371-375
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• 2024

Epoxy resins are widely used in various fields due to their high adhesion, mechanical strength, and solvent resistance. However, as the volume decreases during the hardening process and the cooling process after hardening, stress is generated and when an external force is applied, the brittle material exhibits destruction behavior. To complement this, research has been conducted using inorganic nanofillers such as halloysite nanotube(HNT). HNT has a nanotube structure with the chemical formula of Al₂Si₂O₅(OH)₄·nH₂O and is a natural sediment of aluminosilicate. It has been used as additive to improve the mechanical properties of epoxy composites with exchange of amine group as a terminal functional group. In order to simplify complicated procedures of common wet method, a dry coating machine was designed and used for amine group exchange in previous research. In this study, they were applied as filler in epoxy composites, and mechanical properties such as tensile strength and flexural strength of composites were examined.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.239-240
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• 2008

As semiconductor devices are scaled down for better performance and more functionality, the Cu-based interconnects suffer from the increase of the resistivity of the Cu wires. The resistivity increase, which is attributed to the electron scattering from grain boundaries and interfaces, needs to be addressed in order to further scale down semiconductor devices [1]. The increase in the resistivity of the interconnect can be alleviated by increasing the grain size of electroplating (EP)-Cu or by modifying the Cu surface [1]. Another possible solution is to maximize the portion of the EP-Cu volume in the vias or damascene structures with the conformal diffusion barrier and seed layer by optimizing their deposition processes during Cu interconnect fabrication, which are currently ionized physical vapor deposition (IPVD)-based Ta/TaN bilayer and IPVD-Cu, respectively. The use of in-situ etching, during IPVD of the barrier or the seed layer, has been effective in enlarging the trench volume where the Cu is filled, resulting in improved reliability and performance of the Cu-based interconnect. However, the application of IPVD technology is expected to be limited eventually because of poor sidewall step coverage and the narrow top part of the damascene structures. Recently, Ru has been suggested as a diffusion barrier that is compatible with the direct plating of Cu [2-3]. A single-layer diffusion barrier for the direct plating of Cu is desirable to optimize the resistance of the Cu interconnects because it eliminates the Cu-seed layer. However, previous studies have shown that the Ru by itself is not a suitable diffusion barrier for Cu metallization [4-6]. Thus, the diffusion barrier performance of the Ru film should be improved in order for it to be successfully incorporated as a seed layer/barrier layer for the direct plating of Cu. The improvement of its barrier performance, by modifying the Ru microstructure from columnar to amorphous (by incorporating the N into Ru during PVD), has been previously reported [7]. Another approach for improving the barrier performance of the Ru film is to use Ru as a just seed layer and combine it with superior materials to function as a diffusion barrier against the Cu. A RulTaN bilayer prepared by PVD has recently been suggested as a seed layer/diffusion barrier for Cu. This bilayer was stable between the Cu and Si after annealing at $700^{\circ}C$ for I min [8]. Although these reports dealt with the possible applications of Ru for Cu metallization, cases where the Ru film was prepared by atomic layer deposition (ALD) have not been identified. These are important because of ALD's excellent conformality. In this study, a bilayer diffusion barrier of Ru/TaCN prepared by ALD was investigated. As the addition of the third element into the transition metal nitride disrupts the crystal lattice and leads to the formation of a stable ternary amorphous material, as indicated by Nicolet [9], ALD-TaCN is expected to improve the diffusion barrier performance of the ALD-Ru against Cu. Ru was deposited by a sequential supply of bis(ethylcyclopentadienyl)ruthenium [Ru$(EtCp)_2$] and $NH_3$plasma and TaCN by a sequential supply of $(NEt_2)_3Ta=Nbu^t$ (tert-butylimido-trisdiethylamido-tantalum, TBTDET) and $H_2$ plasma. Sheet resistance measurements, X-ray diffractometry (XRD), and Auger electron spectroscopy (AES) analysis showed that the bilayer diffusion barriers of ALD-Ru (12 nm)/ALD-TaCN (2 nm) and ALD-Ru (4nm)/ALD-TaCN (2 nm) prevented the Cu diffusion up to annealing temperatures of 600 and $550^{\circ}C$ for 30 min, respectively. This is found to be due to the excellent diffusion barrier performance of the ALD-TaCN film against the Cu, due to it having an amorphous structure. A 5-nm-thick ALD-TaCN film was even stable up to annealing at $650^{\circ}C$ between Cu and Si. Transmission electron microscopy (TEM) investigation combined with energy dispersive spectroscopy (EDS) analysis revealed that the ALD-Ru/ALD-TaCN diffusion barrier failed by the Cu diffusion through the bilayer into the Si substrate. This is due to the ALD-TaCN interlayer preventing the interfacial reaction between the Ru and Si.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.3
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• pp.174-186
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• 2007

Amphora coffeaeformis and Achnanthes longipes are commonly found as dominant benthic microalgae in Jeju coastal water throughout the year. In order to investigate pharmaceutical uses of these diatoms, each single species was isolated with micropipette under phase contrast microscope and subcultured with synthetic seawater media which was enriched with F/2 media, trace metal solution and $Na_2SiO_3$). Growth characteristics of these species were also determined with different combination of salinity, nutrients concentration and temperature. Thereafter, mass culture of each species was done based on the maximum growth condition. Biomass was collected after two weeks of mass culture and freeze dried for antioxidant study. The antioxidant properties of different fractions (n-hexane, chloroform and ethylacetate) obtained by solvent fractionation of 80% methanolic extract of two microalgae were investigated for free radical, reactive oxygen species scavenging (Super oxide, Hydrogen peroxide, Hydroxyl radical and Nitric oxide), metal chelating and lipid peroxidation inhibition activities. All fractions of A. longipes showed higher $DPPH^{\cdot}$ (free radical) scavenging activities (n-hexane: 89.0%, Chloroform: 76.0%, Ethylacetate: 66.0%, Methanol: 90.6% and aqueous residue: 63.0%). N-hexane fraction of A. longipes showed significantly higher activity (49.0%) on nitric-oxide. Ethylacetate fraction of A. longipes and aqueous residue of A. coffeaeformis exhibited 64.0% and 75.6% metal chelating activity which was higher than commercial antioxidants (${\alpha}$-tocopherol: 18.0% and BHT: 16.0%). The n-hexane fraction of A. coffeaeformis had 67.5% activity on $DPPH^{\cdot}$. Chloroform and n-hexane fractions of A. coffeaeformis exhibited 46.2% and 47.6% $H_2O_2$ scavenging effects which were closely similar to commercial antioxidants (${\alpha}$-tocopherol: 49.2% and BHT: 58.6%). Chloroform and ethylacetate fractions of A. longipes and fraction of n-hexane and chloroform of A. coffeaeformis showed better lipid peroxidation activities than ${\alpha}$-tocopherol. These data suggest that both organic and aqueous fractions have good antioxidative compounds with different antioxidant properties.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.54-54
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• 1999

다이아몬드 합성시 질소 첨가는 Cn 화합물의 합성가능성을 비롯하여 다이아몬드의 질소 도핑, 성장 속도 및 결정성 변화 등 다양한 관점에서 중요한 의미를 가지고 있다. 본 연구에서는 다이아몬드의 일반적인 합성조건에서 질소를 첨가하여 합성된 막의 형상 및 상 변화에 대해 고찰하였다. 막은 다이아몬드 전처리시킨 Si 기판위에 microwave plasma CVD 장치를 이용하여 합성하였다. 유입되는 혼합가스(CH4+H2+N2)에서 N2 첨가량을 0-95%까지 변화시켰다. 이때 CH4 농도는 5%로 고정하였고, 합성온도는 90$0^{\circ}C$-115$0^{\circ}C$까지 변화시켰다. 이와 같이 합성된 막의 표면조직 및 성장 두께를 측정하기 위해 주사전자현미경을 이용하였다. 상의 분석은 Raman, XRD 및 TEM 분석을 이용하였으며, 조성분석을 위해 XPS 및 AES를 사용하였다. 질소 첨가량에 따라 합성된 막은 첨가하지 않은 경우에 다이아몬드 결정에서 시작하여 질소첨가에 따라 결정면이 깨지는 것으로 나타났다. 그러나 30%, 45%의 경우는 다시 결정면이 나타났다. 다량의 질소가 첨가되었을 때, 다시 결정면을 보이는 다이아몬드가 합성된 것은 매우 흥미로운 결과이다. 한편 질소와 메탄만의 기체하에서는 다시 결정면이 관찰되지 않았다. 이들 상의 구조는 XRD 및 TED 분석을 통해 모두 다이아몬드로 확인되었다. 기체내의 질소의 첨가에 관계없이 고상내에 질소는 확인되지 않았다. 따라서 이방법에 의한 CN 화합물의 합성은 힘든 것으로 보여진다. 이들 실험 결과를 근거로 온도 및 조성에 따른 기체의 열역학적 계산을 통하여 합성거동과의 연관성을 검토하였다. anode는 매우 높은 충전용량을 갖는데 첫 번째 방전시에 Li2O를 생성하여 비가역적 반응을 나타내고 계속되는 충방전 동안 Li-Sn 합금이 생성되어 2차전지의 가역적 반응을 가능하게 한다. SnO2 는 대기중에서 Li 금속보다 안정하기 때문에 전지의 제작 공정 및 사용 면에서 매우 우수한 물질이지만 아직까지 SnO2 구조적 특성과 전지의 충, 방전 특성에 대한 관계의 규명을 위한 정확한 정설은 제시되고 있지 못하다. 본 연구에서는 TFSB anode 물질로써 SnOx박막을 상온에서 여러 전도성 콜렉터 위에 증착하여 그 충, 방전 특성을 보고하였다. 증착된 SnOx박막의 표면은 SEM, AFM으로 분석하였으며 구조의 분석은 XR와 Auger electron spectroscope로 하였다. 충, 방전 특성을 분석하기 위하여 리늄 foil을 대극과 참조 전극으로 하여 EC:DMC=1:1, 1M LiPF6 액체 전해질을 사용한 Half-Cell를 구성하여 100회 이상의 정전류 충, 방전 시험을 행하였다. Half-Cell test 결과 박막의 구조, 콜렉터의 종류 및 Sn/O비에 따라 서로 다른 충, 방전 거동을 나타내었다.다. 거의 없었다. 5mTorr 일 때가 가장 좋았다.수 있음을 알 수 있었다. 그러므로, RNA바이러스의 하나인 BVDV의 viral replicon을 이용하여 다양한 종류의 포유동물 세포에 유전자 발현벡터로써 사용할 수 있음으로 post-genomics시대에 다양한 종류의 단백질 기능연구에 맡은 도움이 되리라 기대한다.다양한 기능을 가진 신소재 제조에 있다. 또한 경제적인 측면에서도 고부가 가치의 제품 개발에 따른 새로운 수요 창출과 수익률 향상, 기존의 기능성 안료를 나노(na

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.4
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• pp.347-355
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• 1986

The Sonakdong river is very important water source not only for agricultural water of Kimhae field but also for fishery water. Recently the middle and lower areas of the river have the tendency to be heavily contaminated by domestic sewage and agricultural chemicals. Fifty six water samples were collected from 8 stations from July to December in 1985 for the experiment (Fig. 1). To evaluate the water quality, pH, water temperature, electrical conductivity, chloride ion, nutrients ($NO^{-}_{2}-N,\;NO^{-}_{3}-N,\;NH^{+}_{4}-N,\;PO^{3-}_{4}-P,\;SiO_2-Si$), total coliform, fecal coliform, and fecal streptococcus were determined. Range and mean value of the samples were as follows; pH $6.3{\sim}9.4$, 7.91; water temperature $6.1{\sim}34.8^{\circ}C,\;23.88^{\circ}C$; electrical conductivity (from St. A to G) $1.575{\times}10^2{\sim}30.50{\times}10^2{\mu}{\mho}/cm,\;6.57{\times}10^2{\mu}{\mho}/cm$; chloride ion $23.5{\sim}14,300mg/l$, 770.0mg/l; nitrite-nitrogen $0.007{\sim}0.110mg/l$, 0.053mg/l; nitrate-nitrogen $0.001{\sim}1.638mg/l$, 0.649 mg/l; ammonia-nitrogen $0.017{\sim}4.200mg/l$, 0.497mg/l; phosphate-phoshorus $0.011{\sim}0.281mg/l$, 0.086mg/l; and silicate-silicious $2.4{\sim}6.5mg/l$, 4.43mg/l. Electrical conductivity and chloride ion of the station F(Chomanpo) were $2.676{\times}10^2{\mu}{\Omega}cm$ and 123.99mg/l which were lower than those of others. Among the analyzed nutrients, silicate-silicious concentration was the highest through all the samples. The bacterial density of the samples ranged $36{\sim}110,000/100ml$ for total coliform, $15{\sim}46,000/100ml$ for fecal coliform and $3.6{\sim}15,000/100ml$ for fecal streptococcus. The range and the mean of the TC/FC ratio were $3.0{\sim}9.6$, 5.51 and those of the FC/FS ratio were $1.1{\sim}9.2$, 6.19, respectively. On the other hand, fecal coliform was not detected in about $78\%$ of the water samples examined. Composition of coliform was $52\%$ Escherichia coli group, $3\%$ Citrobacter freundii group, $13\%$ Enterobacter aerogenes group and $31\%$ others.

• Clean Technology
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• v.6 no.1
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• pp.61-69
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• 2000

In this study, generation process and properties of inorganic industrial waste which can be used in cement industry were investigated. The scheme of recycling to use the selected waste as raw materials, mineralizer and flux, admixture and raw materials for special cement was decided and then various experiments were carried out. The experimental results were as follows ; In the use of industrial waste as raw materials, ferrous materials could be substituted by Cu-slag, Zn-slag, electric arc furnace or convertor furnace slag etc., and a siliceous material could be substituted by sand from cast-iron industry. By-products from sugar or fertilizer industry, which has $CaF_2$ as the main component, and jarosite from Zn refinery enabled clinker phases to be formed at lower temperature by $100{\sim}150^{\circ}C$. Adding Cu slag and STS sludge in proper proportion to cement improved properties of cement. Fly ash and limestone powder as admixture had the same effect on cement. As a raw material for special cement, aluminium waste sludge could be used in making ultra early strength cement, which had the compressive strength of $300kg/cm^2$ within 2hours. And two different ashes from municipal incinerator could be raw materials of the cement which was mainly composed of $C_3S$ and $C_{11}A_7{\cdot}CaCl_2$ as clinker phases.

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.645-652
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• 1991

The stability constants$(K_f)$ of the complexes of some transition and post-transition metal ions (Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ), Zn(Ⅱ), Cd(Ⅱ), Pb(Ⅱ), Hg(Ⅱ)) with $N_2O_3$-donor macrocyclic ligand, 1,15-diaza-3,4 : 12,13-dibenzo-5,8,11-trioxacyclooctadecane ($NtnOdienH_4$), have been determined by potentiometry in aqueous solution at $25^{\circ}C$. Log $K_f$ values of the complexes were : Co(Ⅱ): 3.83, Ni(Ⅱ) : 4.56, Cu(Ⅱ) : 7.74, Zn(Ⅱ) : 4.98, Cd(Ⅱ) : 3.91, Pb(Ⅱ) : 6.65, and Hg(Ⅱ) : 14.87. The order of stabilities of transition metal complexes was the same as the natural order of stability proposed by Williams-Irving. In post-transition metal complexes, the order of stabilities was Cd(Ⅱ) < Pb(Ⅱ) < Hg(Ⅱ), and the covalent character in metal ion-donor atoms bonds appeared a dominant factor in the stability. In methanol solution, each metal ion forms 1 : 1 complex, while Ni(Ⅱ) ion forms both 1 : 1 and 1 : 2 complexes. It was confirmed by $^1H-$ and $^{13}C-$NMR spectral study that the nitrogen atoms in the ligand were major contributors for the complexation of post-transition metal ions with the ligand. It was shown, by elementry analysis, electrical conductivity and magnetic susceptibility measurements, and spectral analysis, that solid Cu(Ⅱ)-and Zn(Ⅱ)-complexes have a distorted octahedral and a tetrahedral structure, respectively.

• Applied Biological Chemistry
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• v.7
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• pp.15-19
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• 1966

In order to investigate the stability of the major component of malathion E.C. product, dimethyl S-(1, 2-dicarboxyethoxyethyl) dithiophosphate, toward the quality of glasswares as container, the amount of extractable inorganic components, change of pH and decomposition of the major component of the product were examined during the storage in brown-colored bottles of 100 ml. volume from 3 different companies in comparison with that in a Pyrex flask. 1. Malathion E.C. product was put in three containers A,B and C, and any changes occurring in storage were analyzed at three intervals of 60, 120 and 240 days. 2. It was shown that the amounts of Si, Mg, K, Ca, and Na extracted during these periods of storage differed markedly depending on the qualify of container. Container A revealed ten times higher extraction of Na and Ca than container B and C in a 8-month period. 3. Three commercial containers revealed the shift of pH from 6.5 to alkaline reaction in the storage whereas the Pyrex flask did not show any detectable change. In particular, the pH in container A changed to 9.2 in 60 days and 9.9 in 240 days. 4. The decomposition of malathion was the greatest in container A which showed the decomposition of 7.37% in 240 days. On the other hand, 0.5% was decomposed in the Pyrex flask. 5. The decemposition of malathion had a high correlation with the change of pH of water· in the same container, $r^2$ being 0.899. From the above results, it is concluded that about 10% of malathion E.C. product is decomposed in a year due to the alkaline metallic salts extracted from the container when it is stored in glassware bottles of lower quality.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.2
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• pp.123-129
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• 2006

A long-term experiment was carried out to examine the effects of compost on the long-term trends and synergy effects with chemical fertilizer and saving the chemical fertilizers of paddy cropping. The experiment was conducted for the past 36 years with constant amounts of N, P, K and compost in a paddy field at Milyang, South Korea. Grain yield was significantly increased in the plots with compost application. Twenty five years after the compost treatment, grain yield was significantly increased and it reached almost 90% of NPK plots. The effect of rice straw compost on grain yield was not clear during the early cropping years about 60%, but it slightly increased there after about 95% during the late five years. In compost plots, soil organic matter content, K and $SiO_2$ was greater in the compost applied plots than with application of recommended doses of NPK. However, soil pH was reduced in compost applied plots and Ca, and Mg were remained unchanged when compared to the application of recommended doses NPK. Soil nutrient contents were less in compost applied plots than with the application of recommended doses of NPK along with compost but was found to be increased than that of un-fertilized plots. The present study indicated that the application of rice straw compost with NPK is the best of all and followed by NPK and Compost. However, treatment of Compost is time consuming and hard working desired and eventually non economical practice in mechanized agricultural systems, even though Compost is very useful source of improving the soil fertility and its physical characteristics and also the application of inorganic N and P are essential for sustaining high yield.

• Ocean and Polar Research
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• v.26 no.3
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• pp.401-414
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• 2004

Temperature, salinity, alkalinity, pH, nutrient, chlorophyll, and iron were measured within the upper 250m water column around the Antarctic Polar Front in the Scotia Sea from late November to early December 2001. Temperature and salinity showed a rapid change across the Polar Front, and the temperature minimum layer existed only in the southern area of the Polar Front. Total $CO_2$ and nutrient concentrations were relatively high and increased rapidly with water depth in the southern area of the Polar Front, which was resulted from upwelling of the Antarctic deep water containing high concentrations of total $CO_2$ and nutrient. ${\Delta}C:{\Delta}N:{\Delat}P$ ratios measured in the norhem and southern areas of the Polar Front were 75:11.4:1 and 84:12.5:1, respectively, which were lower than the Redfield ratio. ${\Delta}Si:{\Delta}N$ ratio (3.65) measured in the southern area of the Polar Front was two times higher than that (1.95) in the northern area. These two ratios were higher than the ratio (1.0) measured in the temperate and tropical oceans. Chlorophyll concentrations were extremely high in the area of $59^{\circ}{\sim}60^{\circ}S$, which was attributed to favorable environmental conditions for phytoplankton growth in this area, such as sufficient iron, high water column stability, and high silicate concentration.