• Korean Journal of Food Science and Technology
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• v.37 no.2
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• pp.312-317
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• 2005

Chemical composition, and mineral and heavy metal contents of Yeomsan and Baekso sun-dried salts (1-5-year-old) were determined. Moisture contents (Yeomsan, 6.07-17.02%; Baekso, 4.29-16.15%) and pH (Yeomsan, 5.92-6.31; Baekso, 5.52-6.23) decreased as age of salts increased, while NaCl contents (Yeomsan, 80.35-92.74%; Baekso, 81.06-94.58%) increased with increasing storage period of salts. Older salts had lower content of water-insoluble matters. Nitrate content was not affected by aging of salts, whereas nitrite content was lower in older salts. Sulfate content of sun-dried salt decreased with aging of salt. Average concentrations (ppm wet weight) of major minerals in Yeomsan and Baekso sun-dried salts were: Mg, Mg, 1002-119; K, 1062-3411; Ca, 1503-3437; Li, 25-101; Ge, 8.35-0.21; Si, 43.99-6.48; and Mn, 6.79-1.55. Mineral content generally decreased with salt aging. Among heavy metals, Hg was not detected in all salts, and Cd (0.02-0.04ppm) was not affected by storage period. Pb was not detected in 5-year-old salts. Older salts showed brighter color than younger ones.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.211-211
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• 1999

Titanium nitride (TiN) thin films have useful properties including high hardness, good electrical conductivity, high melting point, and chemical inertness. The applications have included wear-resistant hard coatings on machine tools and bearings, decorative coating making use of the golden color, thermal control coatings for widows, and erosion resistant coatings for spacecraft plasma probes. For all these applications as feature sizes shrink and aspect ratios grow, the issue of good step coverage becomes increasingly important. It is therefore essential to manufacture conformal coatings of TiN. The growth of TiN thin films by chemical vapor deposition (CVD) is of great interest for achieving conformal deposition. The most widely used precursor for TiN is TiCl4 and NH3. However, chlorine impurity in the as-grown films and relatively high deposition temperature (>$600^{\circ}C$) are considered major drawbacks from actual device fabrication. To overcome these problems, recently, MOCVD processes including plasma assisted have been suggested. In this study, therefore, we have doposited Ti(C, N) thin films on Si(100) and D2 steel substrates in the temperature range of 150-30$0^{\circ}C$ using tetrakis diethylamido titanium (TDEAT) and titanium isopropoxide (TIP) by pulsed DC plamsa enhanced metal-organic chemical vapor deposition (PEMOCVD) method. Polycrystalline Ti(C, N) thin films were successfully grown on either D2 steel or Si(100) surfaces at temperature as low as 15$0^{\circ}C$. Compositions of the as-grown films were determined with XPS and RBS. From XPS analysis, thin films of Ti(C, N) with low oxygen concentration were obtained. RBS data were also confirmed the changes of stoichiometry and microhardness of our films. Radical formation and ionization behaviors in plasma are analyzed by optical emission spectroscopy (OES) at various pulsed bias and gases conditions. H2 and He+H2 gases are used as carrier gases to compare plasma parameter and the effect of N2 and NH3 gases as reactive gas is also evaluated in reduction of C content of the films. In this study, we fond that He and H2 mixture gas is very effective in enhancing ionization of radicals, especially N resulting is high hardness. The higher hardness of film is obtained to be ca. 1700 HK 0.01 but it depends on gas species and bias voltage. The proper process is evident for H and N2 gas atmosphere and bias voltage of 600V. However, NH3 gas highly reduces formation of CN radical, thereby decreasing C content of Ti(C, N) thin films in a great deal. Compared to PVD TiN films, the Ti(C, N) film grown by PEMOCVD has very good conformability; the step coverage exceeds 85% with an aspect ratio of more than 3.

• Journal of Electrical Engineering and Technology
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• v.1 no.3
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• pp.366-370
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• 2006

We investigated the negative differential resistance (NDR) property of self-assembled 4,4-di(ethynylphenyl)-2'-nitro-l-(thioacetyl)benzene ('nitro-benzene'), which has been well known as a conducting molecule [1], Self-assembly monolayers (SAMs) were prepared on Au (111), which had been thermally deposited onto pre-treated $(H_2SO_4: H_2O_2=3:1)$ Si, The Au substrate was exposed to a 1mM solution of 1-dodecanethiol in ethanol for 24 hours to form a monolayer. After thorough rinsing of the sample, it was exposed to a $0.1{\mu}M$ solution of nitro-benzene in dimethylformamide (DMF) for 30 min and kept in the dark during immersion to avoid photo-oxidation. Following the assembly, the samples were removed from the solutions, rinsed thoroughly with methanol, acetone, and $CH_2Cl_2$, and finally blown dry with $N_2$. Under these conditions, we measured the electrical properties of SAMs using ultra high vacuum scanning tunneling microscopy (UHV-STM) and scanning tunneling spectroscopy (STS) [2]. As a result, we confirmed the properties of NDR in between the positive and negative region.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.199-203
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• 2001

온양온천지구의 13개 온천공에서 채취한 온천수의 수질 자료를 이용하여 심부 온천수와 천부 지하수의 혼합비를 추정하였다. 온천수의 pH, EC, 및 주요 이온의 농도는 40~54$^{\circ}C$의 범위를 나타내는 온천수의 온도와 뚜렷한 선형의 비례관계를 나타내며, 수온이 낮아질수록 천부 지하수의 수질 특성에 가까워지는 특성을 보인다. pH, $K^{+}$, F$^{-}$, 및 Si는 온도와 정(+)의 비례관계를, $Ca^{2+}$, $Mg^{2+}$, Cl$^{-}$, HCO$_3$$^{-}$, SO$_4$$^{2-}$ , NO$_3$$^{-}$ 및 EC는 부(-)의 비례관계를 나타낸다. 온천수의 온도와 수질과의 이러한 상관성은 수질 특성이 상이한 고온의 심부 온천수와 저온의 천부 지하수가 각 온천공에서 서로 다른 비율로 혼합되어 나타난 결과로 해석된다. 최고 온도를 나타내는 온천수와 온천지구 내 지하수의 수질을 끝 성분(end member)으로 가정하고 혼합비를 계산한 결과, 온천지구에서 현재 채수되는 온천수에는 20% 내외의 천부 지하수가 혼합되고 있는 것으로 나타났다. 온천수와 지하수의 수질 자료를 파이퍼 다이어그램에 도시한 결과 $Na^{+}$-HCO$_3$$^{-}$의 유형을 나타내는 13개 온천수는 전체적으로 직선 상에 분포하는 경향을 보였으며, $Ca^{2+}$-HCO$_3$$^{-}$의 유형을 나타내는 지하수는 직선의 연장선상에 분포하여 온천수와 지하수의 혼합이 일어나고 있음을 보여준다. 온천공 수질 검층 결과, 심도 145m를 경계로 지하수와 온천수가 상하부에 부존되어 있으며, 경계부에서 혼합이 발생하고 있는 것으로 추정된다.

• Journal of the Korean Society for Heat Treatment
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• v.2 no.4
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• pp.1-10
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• 1989

To investigate the influence of temperature on the TiN film, it was deposited on the STC-3 steel and Si-wafer from $TiCl_4/N_2/H_2$ gas mixture by using the radio frequency plasma assisted chemical vapor deposition. The deposition was performed at temperature of $400^{\circ}C-500^{\circ}C$. The results showed that crystalline TiN film was deposited over $480^{\circ}C$, and all specimens showed the crystalline TiN X-ray diffraction peaks after vacuum heat treatment for 3 hrs, at $1000^{\circ}C$, $10^{-5}torr$. While the film thickness was increased above $480^{\circ}C$, it was decreased under $480^{\circ}C$ as temperature increased. And the contents of titanium were increased and it of chlorine were decreased as temperature increased. Because temperature increase was attributed to the increase in the density of TiN film, surface hardness of TiN film was increased with temperature.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.3
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• pp.213-236
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• 2001

The ionic composition of soil solution is related to a nutrient uptake by plant. Many models for estimating ionic composition of solution have been developed, and most of them have been used for calculating a content of mineral and ionic species in a geochemical point of view. An approximation model considering both cation and anion in soil solution was developed. Variables such as pH, Eh, EC, cations(K, Ca, Mg. Na, Fe, Mn, Al, $NH_4{^+}$), anions(Si, S, P, CY, $NO_3{^-}$, $HCO_3{^-}$ and chemical equilibria of ionic species in soil solution were input into Excel sheet. The activities of soluble ion, ionpairs and complexes of input element were estimated by Newton-Raphson method using conditional equilibrium constant calculated by Davies equation and special models. Equilibrium contents of insoluble minerals and complexes were also calculated.

• Korean Journal of Materials Research
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• v.11 no.4
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• pp.251-257
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• 2001

A present semiconductor cleaning technology is based upon RCA cleaning, high temperature process which consumes vast chemicals and ultra Pure water(UPW). This technology gives rise to the many environmental issues, therefore some alternatives have been studied. In this study, intentionally contaminated Si wafers were cleaned using the electrolyzed water(EW). The EW was generated by an electrolysis equipment which was composed of anode. cathode, and toddle chambers. Oxidative water and reductive water were obtained in anode and cathode chambers, respectively. In case $NH_4$Cl electrolyte, the oxidation-reduction potential(ORP) and pH for anode water(AW) and cathode water(CW) were measured to be +1050mV and 4.7, and -750mV and 9.8, respectively. For cleaning metallic impurities, AW was confirmed to be more effective than that of CW, and the particle distribution after various particle removal processes was shown to be same distribution.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.139-139
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• 2016

반도체 다마신배선용 도금용 구리도금첨가제는 대표적으로 accelerator, suppressor 및 leveler 첨가제를 사용하여 다마신 패턴을 채우고 평탄화를 시킬 수 있다. Si 반도체 공정기술에 기반한 정확한 구조분석을 통해 각각의 첨가제의 기능이 비교적 체계적으로 연구되었으며, 최근에는 유속영향을 많이 받는 것으로 알려진 leveler 첨가제에 대한 연구가 활발히 진행되고 있다. 본 연구는 대표적 leveler 첨가제의 하나인 Janus Green B(JGB, $C_{30}H_{31}ClN_6$)를 0 ~ 1 mM을 첨가하여 Si 기판위에 증착된 Cu 씨드층 상의 도금후 표면상태 및 불순물의 농도를 분석하고, 이 박막층들의 결정립 성장 경향성을 electron backscattered diffraction(EBSD) 분석을 통해 진행하였다. C, H, N 등의 불순물이 JGB 농도와 선형적 관계를 가지고 증가하는 것을 알 수 있었으며, S와 O의 불순물도 JGB 농도 증가에 따라 증가하는 것을 알 수 있었다. 또한 0.1 mM 첨가한 경우에 60% 정도 결정립 성장이 진행된 것을 알 수 있었으며, 0.2 mM을 넣은 경우에는 결정립 성장이 일어나지 않은 것을 알 수 있었다. 흥미로운 점은 4 point probe를 통한 면저항 측정을 통해 EBSD를 통한 결정립성장이 관찰되지 않은 0.2 mM JGB를 첨가한 경우에 대해서도 면저항의 감소가 관찰되며, 오히려 JGB 농도가 높을수록 이러한 면저항의 감소가 빠르게 시작되는 것을 관찰할 수 있었다. 이는 JGB 농도 증가에 따라 박막층의 불순물의 농도가 증가하고 막내에 존재하는 불순물의 농도가 증가하면 내부응력장이 커짐으로 인해 더욱 빠른 속도로 불순물의 재배치가 일어난 것으로 보인다. 이러한 불순물이 결정립계면에 편석되는 경우에 pinning을 통해 결정립계면의 이동을 저하시킬 수 있으므로 결정립의 성장 억제가 가능해진 것으로 판단된다.

• Korean Journal of Materials Research
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• v.20 no.3
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• pp.167-173
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• 2010

In this study, we used activated carbon (AC) and titanium oxysulfate as a titanium precursor to prepare carbon/titania composites. We then mixed it with bentonite in different ratios to make a carbon/titania/bentonite monolith for use in architecture bricks by using Phenolic rosin (PR) as a bonding agent. The physicochemical properties of the prepared composites were analyzed by BET surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), self-cleaning effect and bactericidal tests. The BET surface areas increased as the ratio of carbon/titania composites increased. The SEM microscopy showed that the $TiO_2$ and bentonite were coated on the surface of the AC. The XRD patterns showed a mixture structure of anatase and rutile of $TiO_2$ with a clear $SiO_2$ structure. The EDX spectra of the carbon/titania/bentonite monolith confirmed the presence of various elements, namely C, O, Ti and Si, as well as other, impure elements. Moreover, to determine the self-cleaning effect of the carbon/titania/bentonite monolith, we used methylene blue (MB, $C_{16}H_{18}N_3S{\cdot}Cl{\cdot}3H_2O$) in an aqueous solution under the irradiation of visible light. Accordingly, all of the samples had excellent degradation of the MB solution. Furthermore, it was observed that the composites with sunlight irradiation had a greater effect on E. coli than any other experimental conditions.

• Microbiology and Biotechnology Letters
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• v.42 no.1
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• pp.18-24
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• 2014

This study was conducted to investigate optimum conditions for the production of cellulose-degrading crude enzymes by an isolated marine bacterium. A marine microorganism producing an extracellular cellulose-degrading enzyme was isolated from the red seaweed, Grateloupia elliptica Holmes. The isolated bacterium was identified as Cellulophaga lytica by 16S ribosomal RNA gene sequence analysis and physiological profiling and designated as Cellulophaga lytica PKA 1005. The optimum conditions for the growth of Cellulophaga lytica PKA 1005 were pH 7, 2% NaCl, and $30^{\circ}C$ with 36 h incubation time. To obtain the crude enzyme, the culture medium of the strain was centrifuged for 30 min at $12,000{\times}g$ and $4^{\circ}C$, and the supernatant was used as crude enzyme. The optimum conditions for the production of the cellulose-degrading crude enzyme were pH 8, $35^{\circ}C$, 8% carboxyl methyl cellulose, and 60 h reaction time.