• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.231-240
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• 2016

The change in chemical compositions of leachate and medium density fiberboard (MDF) from a laboratory-scale simulated landfill which constructed in a plastic container containing alternating layers of soil and MDF was investigated to evaluate decomposing of MDF in soil. Four treatments were conducted: 1) MDF in soil, 2) MDF only, 3) cured UF resin in soil, and 4) soil only. Molecular weight (MW) distribution of compounds in leachate from soil only treatment did not change over time. In UF resin in soil treatment, the MW distribution shifted to a lower MW distribution over time, while the peak shifted to the left indicated changing to higher MW distribution in leachate from treatment 1 and 2 contained MDF. Higher percent nitrogen in leachate was observed in MDF containing treatments due to the UF resin in the MDF. The percent carbon slightly increased in MDF only while that greatly decreased in MDF in soil treatment maybe due to bacterial activity. The percent of extractable materials from the MDF decreased greatly on day 35 compare to day 0, and subsequently did not change much on day 77. In contrast, percent holocellulose and lignin did not change much over time. No structural change of the wood fiber in MDF occurs during the study. Water-soluble materials from MDF in soil contributed the change in chemical composition of leachate.

• 한국식품영양과학회지
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• 제26권6호
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• pp.1116-1121
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• 1997

Effects of gamma irradiation onf the activity and the properties(amino acid compositions, in vitro digestibility and SDS-PAGE pattern) of proteolytic enzymes were investigated. The proteolytic activity of soluble human serine protease, enzyme in kiwi and pineapple decreased 10% and 30~65% by 5 kGy and 30 kGy, respectively. In dried pancreatin and lysozyme, the proteolytic and antimicrobial activities decreased 6~14% and 10~20% by 5kGy and 40kGy, respectively. The analysis of above 10kGy-irradiated soluble human serine protease by SDS-PAGE revealed radiolysis of the enzyme into protein or peptides of lower molecular weights. The irradiation of skim milk, hammastein casein, and lysozyme up to 40kGy had no deleterious effect on either the in vitro digestibility or amino acid compositions.

• Journal of Nutrition and Health
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• 제8권2호
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• pp.19-26
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• 1975

The role of fat is important from nutritional standpoint. The physiological functions of fat are energy yielding as well as the carrier of fat soluble vitamins, with special activities of essential fatty acids. It is fortunate that Korean families prefer to use vegetable oils rather than those from animal origin. But the problems are focused on better qaulity of food oils with attempt to exploit the available resources. This study was undertaken to inevestigate the fatty acid compositions of Korean origin both from conventional and unconventional resources of gas-liquid chromatography. The results obtained are as follows. 1. The total lipid contents of seeds of red pepper, Korean squash, sesame, perilla (var Japonica), and Korean pine nuts and walnuts were 24.3%, 56.6%, 56.4%, 46.9%, 69.8%, and 67.2%, respectively. 2. The saponification numbers of samples ranged from 190 to 200. It showed that the mean molecular weights of fatty acids composing the lipids were very much closed each other. 3. Iodine numbers of varing seed oils ranged from 96.5 of Korean squash seed oil to 124.6 of walnut oil. Oils obtained from squash seeds and sesame seeds showed significantly lower value, while others ranged from 122 to 125. 4. In the fatty acid compositions, squash seed oil was composed mainly of unsaturated fatty acids, 74.9% of which was oleic acid, whereas red pepper seed oil, pine nut oil, and sesame oil contained linoleic acid as a major component showing 64.4%, 56%, 48.8%, and 47.8%, respectively. In perilla seed oil, the amounts of linoleic and linolenic acids were 14.1% and 58%, respectively which meant nearly three-fourths of the total fatty acidsbeing the unsaturated essential fatty acids. This study will encourage the use of these conventional and unconventional vegetable oils which have highr ratios of polyunsaturated to saturated fatty acids.

• 천문학회보
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• 제46권2호
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• pp.66.3-67
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• 2021

Low-mass stars form by the gravitational collapse of dense molecular cores. Observations and theories of low-mass protostars both suggest that accretion bursts happen in timescales of ~100 years with high accretion rates, so called episodic accretion. One mechanism that triggers accretion bursts is infalling fragments from the outer disk. Such fragmentation happens when the disk is massive enough, preferentially activated during the embedded phase of star formation (Class 0 and I). Most observations and models focus on the gas structure of the protostars undergoing episodic accretion. However, the dust and ice composition are poorly understood, but crucial to the chemical evolution through thermal and energetic processing via accretion burst. During the burst phase, the surrounding material is heated up, and the chemical compositions of gas and ice in the disk and envelope are altered by sublimation of icy molecules from grain surfaces. Such alterations leave imprints in the ice composition even when the temperature returns to the pre-burst level. Thus, chemical compositions of gas and ice retain the history of past bursts. Infrared spectral observations of the Spitzer and AKARI revealed a signature caused by substantial heating, toward many embedded protostars at the quiescent phase. We present the AKARI IRC 2.5-5.0 ㎛ spectra for embedded protostars to trace down the characteristics of accretion burst across the evolutionary stages. The ice compositions obtained from the absorption features therein are used as a clock to measure the timescale after the burst event, comparing the analyses of the gas component that traced the burst frequency using the different refreeze-out timescales. We discuss ice abundances, whose chemical change has been carved in the icy mantle, during the different timescales after the burst ends.

• 한국수정란이식학회지
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• 제31권3호
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• pp.235-242
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• 2016

This study tested the association between genotypes of the single nucleotide polymorphism (SNP) marker, rs81437607 and capric acid (FA_C10_0) compositions in longissimus dorsi muscle in pigs. Eighteen fatty acid (FA) compositions were measured in a total of 974 $F_2$ animals among 1,106 $F_2$ progeny produced between Landrace and Jeju Black Pig (JBP). Among FA compositions tested, we identified a cluster of highly significant SNPs for capric acid compositions on 58 Mb position of Sus scrofa chromosome 12 (SSC12) using genome-wide association study (GWAS) with $F_2$ genotypes from SNP panel analysis. GWAS results showed that the rs81437607 was the highest trait-related SNP marker with capric acid levels. Three genotypes (C/C, C/T and T/T) of rs81437607 marker were found in $F_2$ population by further pyrosequencing. Association analysis results showed the significant differences between rs81437607 genotypes and capric acid compositions (P<0.05). The $F_2$ pigs harboring rs81437607 C/C ($0.119{\pm}0.002%$) and C/T ($0.116{\pm}0.002%$) genotypes showed additively higher levels of capric acid content than those of T/T homozygotes ($0.109{\pm}0.002%$) ($P=1.30{\times}10^{-12}$). These results suggested that the genetic variations of rs81437607 may be helpful to find causative variants and assist as molecular genetic markers for improving the capric acid contents in longissimus dorsi muscle in pigs.

• 공업화학
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• 제4권4호
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• pp.709-714
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• 1993

세탄가는 디이젤 연료의 점화 특성, 특히 점화 지연의 측정인 동시에 동력학적 현상의 엔진측정값이다. 이러한 동력학적인 행동인 연료의 점화특성과 그 분자구조 즉 탄소 유형별 구조적 조성 사이에는 관련이 있다. 분자구조를 세부적으로 평가하고 세탄가를 예측하는데는 Group Additivity Rule이 사용된다. 본 연구에서는 표준 세탄 평가 엔진으로 세탄가들이 측정된 디이젤 연료들에 대하여 분자구조 측정방법 중 하나인 $^{13}C-NMR$ 분광법과 Group Additivity Rule을 사용하여 세탄가를 연료의 탄소 유형별 구조적 조성과 관련시켜 예측하고 세탄가에 대한 이들 분자구조의 영향에 관하여 고찰하였다.

• 접착 및 계면
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• 제5권4호
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• pp.17-23
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• 2004

본 연구에서는 무정형의 폴리카보네이트를 bisphenol-A 및 disphenyl carbonate를 원료로 하여 융용중합방법에 의해 분자량 별로 합성하고 표면처리에 의한 결정화 거동을 살펴보았다. 사용된 결정화 방법으로는 용매 결정화 방법이 사용되었다. 용매의 종류 및 혼합용매의 조성, 온도, 분자량 등에 따른 결정도 및 용융온도의 차이를 DSC, XRD, SEM 등을 이용하여 관찰하였다. 폴리카보네이트의 분자량이 낮음에 따라, 용매 결정화 온도가 높아짐에 따라 용매 결정화에 의한 결정화도가 증가함을 확인할 수 있었으며, 용매 결정화 온도 및 농도가 높아짐에 따라 상대적으로 균일한 결정이 얻어짐을 확인하였다. 또한 혼합용매를 사용함으로써 원하는 표면적을 지닌 결정성 폴리카보네이트를 제조할 수 있었으며, 용매/비용매 비율이 10/90인 혼합용매를 사용한 경우 표면적이 큰 폴리카보네이트를 얻을 수 있었다.

• 한국재료학회지
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• 제22권4호
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• pp.185-189
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• 2012

We report plasma-assisted molecular beam epitaxy of $In_XGa_{1-X}N$ films on c-plane sapphire substrates. Prior to the growth of $In_XGa_{1-X}N$ films, GaN film was grown on the nitride c-plane sapphire substrate by two-dimensional (2D) growth mode. For the growth of GaN, Ga flux of $3.7{\times}10^{-8}$ torr as a beam equivalent pressure (BEP) and a plasma power of 150 W with a nitrogen flow rate of 0.76 sccm were fixed. The growth of 2D GaN growth was confirmed by $in-situ$ reflection high-energy electron diffraction (RHEED) by observing a streaky RHEED pattern with a strong specular spot. InN films showed lower growth rates even with the same growth conditions (same growth temperature, same plasma condition, and same BEP value of III element) than those of GaN films. It was observed that the growth rate of GaN is 1.7 times higher than that of InN, which is probably caused by the higher vapor pressure of In. For the growth of $In_xGa_{1-x}N$ films with different In compositions, total III-element flux (Ga plus In BEPs) was set to $3.7{\times}10^{-8}$ torr, which was the BEP value for the 2D growth of GaN. The In compositions of the $In_xGa_{1-x}N$ films were determined to be 28, 41, 45, and 53% based on the peak position of (0002) reflection in x-ray ${\theta}-2{\theta}$ measurements. The growth of $In_xGa_{1-x}N$ films did not show a streaky RHEED pattern but showed spotty patterns with weak streaky lines. This means that the net sticking coefficients of In and Ga, considered based on the growth rates of GaN and InN, are not the only factor governing the growth mode; another factor such as migration velocity should be considered. The sample with an In composition of 41% showed the lowest full width at half maximum value of 0.20 degree from the x-ray (0002) omega rocking curve measurements and the lowest root mean square roughness value of 0.71 nm.

• 분석과학
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• 제12권2호
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• pp.94-98
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• 1999

Quadrupole Mass Spectrometer를 이용하여 핵연료봉으로부터 포집된 1기업이하 소량의 기체들로부터 그들의 조성과 동위원소비를 구하는 방법을 검토하였다. He, $N_2$, $O_2$, Ar, Kr, Xe의 개별기체와 혼합기체를 이용하여 기체압력과 조성비에 따른 검정곡선의 직선성을 조사하였다. Sample chamber와 analyser chamber 사이에 부착된 molecular leak의 영향을 조사하였으며, 시료와 유사한 조성을 갖는 혼합표준기체로부터 각 기체의 감도를 얻은 후 동일조건에서 시료를 분석하였다. 측정압력 범위에서 Kr과 Xe의 동위원소간 감도차는 크게 나타나지 않았다.

• Journal of Microbiology and Biotechnology
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• 제20권1호
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• pp.138-145
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• 2010

A bacterial strain isolated from soil for its potential to control the anthracnose disease caused by Colletotrichum gloeosporioides was identified as a Bacillus subtilis. Bacillus subtilis CMB32 produced antifungal agents on M9 broth at $30^{\circ}C$. Biosurfactant lipopeptides produced by Bacillus subtilis CMB32 were precipitated by adjusting to pH 2 and extracting using chloroform/methanol, and then were purified using column chromatography and reverse-phase HPLC. The molecular masses of the lipopeptides were estimated by MALDI-TOF mass spectrometry as (a) 1,080, (b) 1,486, and (c) 1,044 Da, respectively. They had cyclic structures and amino acid compositions of (a) Pro, Asx, Ser, Tyr, Glx, (b) Glx, Tyr, Thr, Ala, Pro, lie, and (c) Glx, Leu, Val, Asx, respectively. Further analysis revealed that Bacillus subtilis CMB32 produced three antifungal lipopeptides: (a) iturin A, (b) fengycin, and (c) surfactin A.