• Journal of Life Science
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• v.28 no.11
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• pp.1339-1346
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• 2018

In Korea, edible mushrooms are produced largely on commercial artificial media, so the annual production of spent mushroom substrate (SMS), as a by-product of the mushroom industry, is estimated at over 200 million tons. This SMS is assumed to contain abundant fungal mycelia and pre-fruiting bodies, as well as various nutritive and bioactive compounds that are presently discarded. This study examined the physico-chemical, nutritional, and enzymatic characteristics of uninoculated sterilized medium (USM) and SMS of shiitake mushrooms with the aim of developing a high-value added product from SMS. The contents of crude protein, crude lipid, and ash were higher after the third SMS harvest ($SMS-A-3^{rd}$) than in USM or $SMS-A-1^{st}$. The contents of Ca, Mg, and P in $SMS-A-3^{rd}$ were 2.95, 2.35, and 2.1-fold higher compared than in USM. No As or Cd was detected in USM or SMS. The pH, Brix, and acidity were 4.6, 20.0, and 1.4, respectively in $SMS-A-3^{rd}$, but 5.6, 6.0, and 0.0, respectively, in USM. These results suggest a highly active production of soluble components and organic acids in $SMS-A-3^{rd}$. The distinct color differences noted for USM, $SMS-A-1^{st}$, and $SMS-A-3^{rd}$ could be used as a mycelial growth indicator. Enzyme activity assays using the APIZYM system showed that SMS is a potent source of hydrolysis-related enzymes, especially esterase (C4) and ${\beta}$-glucuronidase. Our results suggested that the SMS of shiitake has a high potential for use in environmental, agricultural, and stock-breeding industries, for example, as active ingredients for sewage treatment, waste-polymer degradation, and feed additives.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.4
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• pp.14-20
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• 1993

비조질강은 1970년대 초반 독일에서 개발된 이래 열처리(Quenching & Tempering)가 필요없는 에너지절약형 강재로서 유럽과 일본의 자동차업계를 중심으로 그 적용량이 지속적으로 증가되고 있다. 열간단조용 비조질강의 물성은 가열온도, 단조온도 및 냉각속도 등 단조공정변수의 영향을 크게 받는다. 본 고에서는 승용차엔진용 크랭크축에의 적용을 위해 SM50C에 V을 0.15% 첨가한 비조질강의 가열온도와 냉각속도에 따른 기계적 성질과 미세조직의 변화를 파악하여 최적단조공정을 정립하고, 크랭크 축시제품을 제작하여 그물성과 내구강도를 평가하고자 한다.

• Journal of the Korean Society of Safety
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• v.8 no.1
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• pp.13-20
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• 1993

It is well known that mechanisms of fracture and fatigue crack propagation depend upon various characteristics such as environmental condition. crack geometry. heat treatment and mechanical properties. It seems to be important for the detailed evaluation of structural integrity to investigate the effects of the above factors on the behavior of structural components which contain flaws. In this paper. it is studied that the fatigue crack propagation of partly heat treated medium carbon steel (SM45C) by high frequency heat treatment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.2
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• pp.210-216
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• 2008

Leuconostoc mesenteroides SM isolated from a raw carrot was used for the fermentation of carrot juice (CJ). Lactic acid fermentation of CJ was performed at $25^{\circ}C$ for 24 hr with $0{\sim}20%$ sucrose concentration, resulting in the production of mucilage. The fermented CJ showed the complete conversion of sugar into dextran after fermentation for 24 hr in the presence of sucrose below 15% concentration. With 15% sucrose, the fermented CJ had pH 3.8, 0.9% acidity, consistency index of $3.5\;Pa{\cdot}s^n$. After cold storage for 3 weeks, fermented CJ showed slight increase in acidity and relatively constant value in pH; however, the consistency index, red color value and viable cell counts were slightly decreased for 3 weeks. The ${\beta}-carotene$ content in CJ was drastically decreased by lactic acid fermentation for 24 hr, indicating $72\;{\mu}g/mL$ as compared to $142\;{\mu}g/mL$. The fermented CJ had improved body texture, red color and stability without sedimentation.

• Korean Journal of Microbiology
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• v.20 no.1
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• pp.11-20
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• 1982

A study was undertaken to examine the effect of curing agents on the stability, curing and segregation of R plasmid pSL100. And also the stability, transfer frequency, and recombination of its segregants obtained from curing agent treatment were studied. Ethidium bromide, acridine orange, and mitomycin-C were used as curing agent. The results obtained were as follows ; 1. The curing agent ethidium bromide, acridine orange, and mitomycin-C were not effective for curing the multiple antibiotic resistant determinant of pSL100 in Salmonella typhimurium and Escherichia coli. However, they induced plasmid segregation with high frequency in S.typhimuruim LT-2strains. TcApSmCm, TcSmCmKm, TcApCm, TcAp, TcKm, Tc segregants were obtained. 2. The resistant markers of the segregents were transferred to S.typhimurium LT-2 strains with high frequencies whereas they were transferred to E.coli K-12 only with low frequencies. 3. The transconjugants obtained from conjugation between two different S.typhimurium segregants were similar to the phenotype of the original R factor pSL100 and the resistant markers were transferred to the S.typhimurium LT-2 or E.coli strain with equal frequencies, indicating that they are recombinants. 4. The transconjugants obtained from conjugation between pSL100 segrgants and pKM101, or pBR322 possessed the resistant markers of the two parental plasmids and they were transferred to both S.typhimurium and E.coli K-12 strains with the same frequencies and maintained stably, suggesting that they are also recombinants. 5. The recombinant pSL100 could be also obtained in rec A-strains of E.coli, suggesting that the gene function of rec A is required for the recombination of pSL100 segregants in E.coli.

• Journal of the Korean Chemical Society
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• v.44 no.2
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• pp.95-101
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• 2000

Macroacyclic transition metal complexes such as $Cu(H_2L[A]).H_2O$, $Cu(H_2L[B]).H_2O$, CuFe(L[A]($NO_3$).$4H_2O$, CuFe(L[B])($NO_3$).$4H_2O$, [$CuGd(H_2L[A])(NO_3)_2](NO_3).2CH_3OH$, [CuGd($H_2L$[B])($NO_3)_2$]($NO_3).2CH_3OH were prepared from the corresponding hexadentate compartmental ligands, $H_4L[A]$ and $H_4L[B]$, which were obtained by the condensation of 2-hydroxy-3-hydroxymethy1-5-methyIbenzaldehyde(HHNNB) and ethylenediamine or l,3-diaminopropane. Ln-macrocyclic([20]DOTA) complexes,[Ln([20]DOTA)($NO_3)(H_2O)$]($NO_3$)2.$xH_2O${Ln(III)=Pr, Sm, Gd, Dy, which had been synthesized from 2,6-diformyl-p-cresol(DFPC), was placed in methanol for 2 days, and [Ln([20] DOTA)($NO_3)(CH_3OH)]^{2+}$ was formed The equilibrium constants (k) for the substitution of coordinated $CH_3OH$ in the Ln-[20]DOTA complexes by various bidentate auxiliary ligands, $L_a$(=o-phenylenediamine,1,10-phenanthroline, ethylenediamine,oxalicacid, malonic acid, acethylacetone) were determined by spectroscopic method at $25^{\circ}C$ and 0.1M $NaClO_4$.The pKa of auxiliary ligands is in the order of o-phenylenediamine < 1,10-phenanthroline < ethylene-diamine, oxalic acid < malonic acid < acethylacetone. However, the equilibrium constant(K) has shown thetrend of ethyleneiamine < 1,10-phenanthroline < o-phenylenediamine, acethylacetone < malonic acid < oxalic acid.

• The Korean Journal of Zoology
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• v.6 no.2
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• pp.21-27
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• 1963

This study is concerned with alterations in chromosomes (numbers and morphology) when the culture of Chinese hamster cells (FAF-28 strain) was treated by steroids, testosterone and DOC. 1. In 200 cells of normal untreated cells as control population the chromosome of stemline was decided as which was contained in 158 cells ; that is , in 79 percent of the population. The average chromosome number in above 20 cells observed was calculated as 23.95 with minimum limit at 20 and maximum limit at 70. 2. Many different chromosome numbers, ranging from 19 to 352 were observed in the 200 cells treated by testosterone. The diploid number of 22 showed the peak of variation curve was counted in 71 cells (35.5%) and an average chromosome number of stemline was 22 which was counted in 74 cells (37%). While all of the chromosome number of stemline was 22 which was counted in 74 cells (37%). While all of the chromosome numbers in the 200 cells observed ranged from 20 to 181 , an average chromosome number was also found to be 30.09. 4. The chromosome component in the cultured normal FAF-28 cells with 22 diploid chromosomeswas as follows ; 9a) 2 paris were long and metacentric (LM), (b) 3 pairs were medium length and metacentric (MM), (c) 3 pairs were small and subtelocentric (SS) and (d) 3 pairs were small and metacentric (SM). 5. The twenty cells with 44 chromosomes were selected at random from each cell population treated with testosterone and DOC , so that chromosome idiogram and morphology could be studies. In the twenty cells of the testosterone treated population the average ratio of above four groups, LM ; MM;Ss:SM, was found to be 8.6 : 10.8:13.5:10.7. On the other hand, the average ratio in the same number of cells of the DOC treated one was 7.7 :11.4:12.5:12.7. 6. The five types of the altered chromosomes morphologically in the hundred cells selected at random from each cell population treated by testosterone and DOC were observed (Type I-V). The thirty-one altered chromosomes were found to be in the testosterone treated cell population and the sixteen in DOC treated.

• Journal of Magnetics
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• v.20 no.1
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• pp.31-39
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• 2015

Macroscopic hysteresis loops and microscopic magnetic moment distributions have been determined by a three-dimensional (3D) model for exchange-coupled Sm-Co/${\alpha}-Fe$/Sm-Co trilayers with in-plane collinear easy axes. These results are carefully compared with the popular one-dimensional (1D) micromagnetic models and recent experimental data. It is found that the results obtained from the two methods match very well, especially for the remanence and coercivity, justifying the calculations. Both nucleation and coercive fields decrease monotonically as the soft layer thickness $L^s$ increases while the largest maximum energy product (roughly 50 MGOe) occurs when the thicknesses of hard and soft layers are 5 nm and 15 nm, respectively. Moreover, the calculated angular distributions in the thickness direction for the magnetic moments are similar. Nevertheless, the calculated nucleation and pinning fields as well as the energy products by 3D OOMMF are systematically smaller than those given by the 1D model, due mainly to the stray fields at the corners of the films. These demagnetization fields help the magnetic moments at the corners to deviate from the previous saturation state and facilitate the nucleation. Such an effect enhances as $L^s$ increases. When the thicknesses of hard and soft layers are 10 nm and 20 nm, respectively, the pinning field difference is as large as 30%, while the nucleation fields have opposite signs.

• Progress in Superconductivity
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• v.11 no.2
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• pp.83-86
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• 2010

There are theoretical and experimental evidences for the pseudo-gap in electron doped cuprates being due to interaction between electrons and anti-ferromagnetism(AFM). A remaining issue is on how AFM correlates with pseudo-gap, and eventually with superconductivity. To elucidate the issue, we have performed temperature dependent angle-resolved photoemission studies of an e-doped cuprate superconductor $Sm_{2-x}Ce_xCuO_4$(SCCO) x=0.18 at 20K and 150K. In the case of $Nd_{2-x}Ce_xCuO_4$, the most well known e-doped cuprate, pseudo-gap disappears at around 100 K for x=0.17. Our experimental result reveals that the pseudo-gap of SCCO exists even at 150K for x=0.18. This result implies that the AFM of SCCO survives even in x=0.18, which agrees with previously reported phase diagram of SCCO. Yet, the superconductivity disappears around x=0.18 for both NCCO and SCCO in spite of the difference in the magnetic order. This result sheds a light on the disappearance of superconductivity on the over-doped side.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.167-167
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• 2013

최근에 산화물 형광체는 황화물 형광체에 비해 높은 화학적 안정성을 나타내기 때문에 백색 발광 다이오드, 전계방출 디스플레이와 플라즈마 디스플레이 패널에 그 응용성을 넓히고 있다. 마그네슘 니오베이트(magnesium niobate, MgNb2O6)는 우수한 유전 특성(상대 유전상수=18.4)을 나타내기 때문에 마이크로파 유전체로 응용 가능하며, 단일상 릴랙서 페라브스카이트(relaxor perovskite) Pb(Mg1/3Nb2/3)O3을 합성하기 위한 전구체 (precursor)로 널리 사용되고 있으며, 나이오븀산염 이온에서 다양한 색상을 방출하는 활성제 이온으로 효율적인 에너지 전달이 일어남으로써 Sm3+, Dy3+, Eu3+와 같은 희토류 이온의 좋은 모체 격자로 개발할 수 있다. 본 연구에서는 마그네슘 니오베이트 MgNb2O6 모체 결정에 다양한 활성제 이온, 즉 Eu3+, Sm3+, Dy3+, Tb3+를 선택적으로 주입하여 발광 효율이 높은 천연색 형광체를 합성하고자 한다. 특히, 모체 결정에 주입되는 활성제 이온 주위의 국소적인 환경이 반전 대칭에서 변형되는 척도를 조사하여 활성제의 주 발광 파장의 세기가 최대가 되는 최적의 조건을 결정하고자 한다. Mg1-1.5xNb2O6:REx3+ 형광체 분말 시료는 초기 물질 MgO, Nb2O5와 희토류 이온을 화학 반응식에 맞게 정밀 저울로 측량하여 플라스틱 용기에 ZrO2 볼과 함께 넣고, 소정의 에탄올을 채운 뒤 밀봉하고서, 300 rpm의 속도로 20시간 볼밀 (ball-mill) 작업을 수행하였다. 그 후, 체(sieve)로 ZrO2 볼을 걸러낸 다음에 혼합된 용액을 각 비커에 담아서 $40^{\circ}C$의 건조기에서 24시간 건조하였고, 건조된 시료를 막자 사발에 넣고 잘게 갈고 80 ${\mu}m$의 체로 걸러낸 후에, 알루미나 도가니에 활성제 이온별로 각각 담아, 전기로에 장입하여 매분당 $5^{\circ}C$의 비율로 온도를 상승시켜 $350^{\circ}C$에서 5시간 동안 하소 공정을 실시한 후에, 온도를 계속 일정한 율로 증가시켜 $1,200^{\circ}C$에서 5시간 동안 소성하여 합성하였다. 합성된 형광체 분말의 결정 구조는 $Cu-K{\alpha}$ 복사선(파장: 1.5406)을 사용하여 X-선회절장치로 측정하였으며, 형광체의 표면 형상은 전계형 주사전자현미경으로 관측하였다. 흡광와 발광스펙트럼은 제논 램프를 광원으로 갖는 형광 광도계를 사용하여 측정하였다. 모체 결정에 활성제 이온 Eu3+, Sm3+, Dy3+, Tb3+가 도핑된 형광체 분말은 각각 적색, 주황색, 황색, 녹색 발광이 관측되었다. 각 발광 스펙트럼과 결정 입자의 크기와 형상 사이의 상호 관계를 조사하였다. 실험 결과로부터, 각 형광체의 발광 파장은 활성제 이온의 종류 와 서로 밀접하게 관련되어 있으며, 형광체 시료 합성시 활성제 이온의 농도를 선택적으로 조절함으로써 발광의 세기를 제어할 수 있음을 확인하였다.