• Journal of Korean Society of Environmental Engineers
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• v.35 no.8
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• pp.586-591
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• 2013

This experiment was performed to enhance $CH_4$ purity of landfill gas by applying gas separator membrane for purified nitrogen gas production. 1:6 area ratios of $1^{st}$ to $2^{nd}$ membrane module was suitable for $CH_4$ recovery. After separation membrane system was installed, 249 tries were performed. Average permeability for $CH_4$ was 28.4% and for $CO_2$ was 94.3%. This can explain nitrogen gas separator membrane can be applied to collect $CH_4$ from LFG. However, nitrogen permeability only reached up to 16.5%. Therefore, the final purified landfill gas concentration was rounded up to 69.7% for $CH_4$, 4.3% for $CO_2$ and 26.0% for $N_2$. For the high degree of $CH_4$ purity, $N_2$ should be kept at least under 2.0% by controlling air inflow to landfill.

• Biomedical Science Letters
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• v.28 no.2
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• pp.109-119
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• 2022

Histone proteins can be modified by the addition of acetyl group or methyl group to specific amino acids. The modifications have different distribution patterns in chromatin. Recently, histone modifications are studied based on ChIP-seq data, which requires reasonable analysis of sequencing data depending on their distribution patterns. Here we have analyzed histone H3K27ac and H3K27me3 ChIP-seq data and it showed that the H3K27ac is enriched at narrow regions while H3K27me3 distributes broadly. To properly analyze the ChIP-seq data, we called peaks for H3K27ac and H3K27me3 using MACS2 (narrow option and broad option) and SICER methods, and compared propriety of the peaks using signal-to-background ratio. As results, H3K27ac-enriched regions were well identified by both methods while H3K27me3 peaks were properly identified by SICER, which indicates that peak calling method is more critical for histone modifications distributed broadly. When ChIP-seq data were compared in different sequencing depth (15, 30, 60, 120 M), high sequencing depth caused high false-positive rate in H3K27ac peak calling, but it reflected more properly the broad distribution pattern of H3K27me3. These results suggest that sequencing depth affects peak calling from ChIP-seq data and high sequencing depth is required for H3K27me3. Taken together, peak calling tool and sequencing depth should be chosen depending on the distribution pattern of histone modification in ChIP-seq analysis.

• Bulletin of the Korean Chemical Society
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• v.26 no.4
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• pp.553-557
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• 2005

The formation of striped phases of unsymmetric hexyl octadecyl disulfide ($CH_3(CH_2)_5SS(CH_2)_{17}CH_3$, HOD) and 1-hydroxyundecyl octadecyl disulfide ($CH_3(CH_2)_{17}SS(CH_2)_{11}$OH, HUOD) on Au(111) and graphite has been investigated by scanning tunneling microscopy (STM) to understand the self-assembly processes of dialkyl disulfides. STM imaging clearly shows the formation of striped phases having corrugation periodicities that are nearly consistent with the molecular length of alkanethiolate moieties formed after the S-S bond cleavage of dialkyl disulfide on a gold surface. On the other hand, self-assembled monolayers (SAMs) of dialkyl disulfides on a graphite surface displayed long-range, well-ordered monolayers with one striped pattern that shows periodicity as a function of molecular length via nondissociative adsorption. From a nonoscopic viewpoint, we have clearly demonstrated that dialkyl disulfide SAMs on gold form via S-S bond cleavage of disulfide.

• Korean Journal of Materials Research
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• v.6 no.3
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• pp.324-332
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• 1996

DLC 박막을 RF 플라즈마 화학증착법(PECVD)을 이용하여 CH4와 CO2기체로부터 합성하였다. 증착압력, CH4와 CO2가스의 조성비, 바이어스 전압(-VB) 등의 증착조건 변화에 따른 증착속도는 증착층의 두께를 알파스텝으로 측정하여 결정하였으며, 박막의 구조 변화에 따른 증착속도는 증착층의 두께를 알파스텝으로 측정하여 결정하였으며, 박막의 구조 변화는 FTIR 분광분석을 이용하여 분석을 행하였다. 이 연구로부터 얻은 실험 결과는 다음과 같다: 1) 증착속도는 증착압력 및 바이어스 전압의 증가에 따라 증가한다. 2)바이어스 전압 300V이상에서, CO2량 증가는 순증착속도를 증가 시킨다. 3) 순수한 CH4가스를 사용할 경우에는 바이어스전압(-VB)이 증가함에 따라 박막내 수소의 함량과 sp3/sp2비는 감소하는 경향을 나타낸다. 4)증착압력이 증가함에 따라 박막내 수소함량은 증가하며, sp3/sp2비는 감소한다. 5)50mTorr의 증착압력에 증착시, CH4-+Co2 혼합가스에서 이산화탄소의 부피분율에 따라서는 박막내 수소함량은 감소하며, sp3/sp2비는 증가한다.

• Journal of the Korean Chemical Society
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• v.39 no.3
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• pp.218-223
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• 1995

A simple and efficient synthesis of new kind of Morindaparvin A derivatives (2~8) containing $-N(CH_3)_2,\;-OMe,\;-NH_2,\;-COOH,\;-CHClC(O)NH_2,\;-CHClCH_2OH\;and\;-CHClC(O)CH_3$ was completed with the reported 1,2-dihydroxyanthraquinone derivatives (9, 10).

• Bulletin of the Korean Chemical Society
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• v.20 no.11
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• pp.1295-1298
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• 1999

Novel platinum(IV) complexes with asymmetric chiral diamine ligands cis,cis,trans-A2PtCl2(X)2 (X = OH, OCOCH3, OCOC2H5, A2 =NH2CH(CH3)CH2NH(c-C6H11)(apcha), NH2CH(CH3)CH2NH(c-C5H9)(apcpa)) have been prepared. One of the platinum(IV) complexes, (apcpa)PtCl2(OCOC2H5)2(6), was subjected to X-ray crystallographic analysis. The crystal structure of (apcpa)PtCl2(OCOC2H5)2 (monoclinic, P21 (No. 4), a = 9.1391(1), b = 22.2517(1), c = 10.0687(1)Å, β= 109.105(1)。 , V = 1934.80(3)Å3 , Z = 4, R1 = 0.0532) exhibits that the platinum atom achieves a typical octahedral arrangement with two nitrogen atoms in cis positions and two carboxylato group in trans positions. The spectroscopic data disclose that these platinum(IV) complexes are stable and their molecular structures are retained in aqueous solution. The title complexes are highly cytotoxic in vitro but do not exhibit oral anticancer activity in vivo.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.394-400
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• 2023

In this study, the tuning phenomena, gas storage capacity, and thermal expansion behaviors of binary (cyclopentylamine + CH₄) and (cyclopropylamine + CH₄) clathrate hydrates were investigated for the potential applications of clathrate hydrates to gas storage. To understand the tuning behaviors of binary (cyclopentylamine + CH₄) and (cyclopropylamine + CH₄) clathrate hydrates, ¹³C solid-state NMR spectroscopy was used, and the results confirmed that maximum tuning factors for the binary (cyclopentylamine + CH₄) and (cyclopropylamine + CH₄) clathrate hydrates were achieved at 0.5 mol% and 1.0 mol% of guest concentration, respectively. The gas storage capacity of binary (cyclopentylamine + CH₄) and (cyclopropylamine + CH₄) clathrate hydrates were also checked, and the results showed the CH₄ capacity of our hydrate systems was superior to that of binary (tetrahydrofuran + CH₄) and (cyclopentane + CH₄) clathrate hydrates. The synchrotron diffraction patterns of these hydrates collected at 100, 150, 200, and 250 K confirmed the formation of a cubic Fd-3m hydrate. In addition, the lattice constant of clathrate hydrates with cyclopentylamine and methane were larger than that with cyclopropylamine and methane due to the effects of molecular size and shape.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.1
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• pp.111-122
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• 1995

12 populatiDns of Ch indicum L. and it's variation antogenous in Tforea were selected throughout the country and their morphological characteristics were studied in this paper. The results are as follows. 1) The mean of the plant height is 97.3cm. Ch. indicunl is 76.5cm and Ch. boreale is 116. 6cm in height. The number of nodes is 58 on the average. The color of the stem is generally black-red in the case of Ch. indicum and is green for Ch. boreale. 2) The leaves of Ch. inficum are smaller In size and thicker than chose of Ch. boreale, and it has a stipule. This fact enables us to distinguish one species from the other, however, the Gyukpo-population of Ch. indicum has a large leaf, and Byunsan-population of Ch. boreale has a stipule so that the above fact is not an exact criterion on which to base one classification. 3) The size of the capitulum is 24.9mm for Ch. indicum and 15.6mm in the case of Ch. boreaje so that the difference between species is admitted. It was confirmed hat the size of the capitulum has positive correlation to that of the pedicel and has egative correlation to the number of flowers, so that of inflorescence, Ch. indicumhas corymb, and Ch. boreale has crowed corymb or umbel-type.The number of ligulates is 19 on the average, which no the difference being founnd between species and populations.4) The cluster analysis of morphological characteristics showed that Ch. indicum wasdivided into two groups, which was shown thought to be due to the difference of speciesbetween Ch. indicum and Ch. boreale. However, it could not be shown that their morphological characteristics explain a geographical relationship between populations

• Journal of the Korean Society of Combustion
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• v.5 no.1
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• pp.7-18
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• 2000

Numerical simulations of counterflow non-premixed $CH_4/C_2HCl_3/Air$ flames added 8%(by volume) C2HCl3 on the fuel side are conducted at atmospheric pressure using a detailed chemical reaction mechanism in order to understand the effect of strain rates. A detailed sensitivity analysis is also performed in order to assess the relative influence of each reaction on the flame established at a strain rate of 200s-1. The structure of flames (i.e., temperature, velocity, and concentration of species) established at both a strain rate of 150s-1 and 300s-1 are investigated. As the strain rate increases, the "flame zone" is restricted to a narrower range and the position of maximum temperature is shifted to the fuel side. The concentrations of major species, H2O, CO, H2, HCl, Cl2, and Cl are decreased with increased strain rate. The reaction involving chlorine, CH4 + Cl $\rightarrow$ CH3 + HCl, instead of the reaction, CH4 + H $\rightarrow$ CH3 + H2 influences the consumption of methane. C2HCl3 + OH $\rightarrow$ CHCl2 + CHOCl and HCl + OH $\rightarrow$ H2O + Cl, are major reactions, through which OH radicals are consumed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.3
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• pp.38-42
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• 2000

Plasma polymerized thin films were manufactured inter-electrode coupled plasma polymerization apparatus. The deposition rate reached its maximum between 40[W] and 100[W]. In the ESCA analysis, peaks revealing -CH2, -CH, -C- were present at 285.4 and 285.5[eV] respectively. The C=O peak at 532.8[eV] and the C-O peak at 533.8[eV], which were grouped with an unignorable amount of oxygen were conformed. In ESR analysis, the curve revealing strong amplification was in saturation, which was affected by weak power. This is considered as a -CH-Ch=Ch- structure containing the Allyl group. The relative permittivity of the plasma polymerized thin films was about 3.5 at a frequency of 100[Hz]∼200[kHz]. The dissipation factor showed allow value of 0.008.