• Journal of Microbiology and Biotechnology
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• 제33권4호
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• pp.552-558
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• 2023

Levulinic acid (LA) is a valuable chemical used in fuel additives, fragrances, and polymers. In this study, we proposed possible biosynthetic pathways for LA production from lignin and poly(ethylene terephthalate). We also created a genetically encoded biosensor responsive to LA, which can be used for screening and evolving the LA biosynthesis pathway genes, by employing an LvaR transcriptional regulator of Pseudomonas putida KT2440 to express a fluorescent reporter gene. The LvaR regulator senses LA as a cognate ligand. The LA biosensor was first examined in an Escherichia coli strain and was found to be non-functional. When the host of the LA biosensor was switched from E. coli to P. putida KT2440, the LA biosensor showed a linear correlation between fluorescence intensity and LA concentration in the range of 0.156-10 mM LA. In addition, we determined that 0.156 mM LA was the limit of LA detection in P. putida KT2440 harboring an LA-responsive biosensor. The maximal fluorescence increase was 12.3-fold in the presence of 10 mM LA compared to that in the absence of LA. The individual cell responses to LA concentrations reflected the population-averaged responses, which enabled high-throughput screening of enzymes and metabolic pathways involved in LA biosynthesis and sustainable production of LA in engineered microbes.

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2001년도 Korean Environmental Mutagen Society
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• pp.43-44
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• 2001

• 복식
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• 제65권3호
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• pp.28-46
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• 2015

The aim of this research is to classify the concept expressed in the mobility of la diff${\acute{e}}$rant play, and supplement logic, which is process of the changeability of fashion style. The specific research questions are as follows: first question deals with the relationship between changeability and la diff${\acute{e}}$rant images, and how la diff${\acute{e}}$rant images are divided by each phase and how their circumduction play is proceeded. The second question is about the important features of the mobility of la diff${\acute{e}}$rant play and the method of la diff${\acute{e}}$rance play. The last topic of this study covers the supplement logic and the condition, and how supplement logic has been applied in the process of changeability of fashion style. This paper deploys a qualitative research method providing a systematic review of the previous studies. To sum it up, the mobility of la diff${\acute{e}}$rant play is the root of power, which is controlling the changeability of fashion style, and the objective of the play is to outline new la diff${\acute{e}}$rant images through spatialization of time. In addition, supplement logicis the method of la diff${\acute{e}}$rant play and the purpose of the logic is to harmonize 'ultimate la diff${\acute{e}}$rant image', which is the phenomenological construction stratum in the state of sub-conscious changeability, and 'immediate la diff${\acute{e}}$rant image', which is the structural construction level stratum in the state of external changeability. This research proves that the intrinsic attribute of changeability is contained the mobility of la diff${\acute{e}}$rant play and supplement logic.

• 대한화학회지
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• 제45권6호
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• pp.507-512
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• 2001

1,2-Bis(4-pyridyl)ethane 존재 하에서, $La(NO_3)_3{\cdot}6H_2O$와 benzene-1,3-dicarboxylic acid($H_2$BDC)가 수열반응하여 〔$La_4$$(BDC)_6$$($H_2$O)_5$〕($H_2$O) (1) 실험식을 갖는 2차원 lanthanum-BDC 배위 고분자가 합성되었다. 화합물의 1의 구조 분석 결과, 이 고분자는 분명히 구별되는 4개의 La금속들을 함유하고 있었다. 3개의 La금속들은 7-배위를 하고 있으며, 이들은 "모자 씌운(capped)"삼각 프리즘, "모자 씌운" 정팔면체, 그리고 오각쌍뿔등의 다른 구조들을 가지고 있다. 나머지 La금속은 8-배위, 사각 반프리즘 (antiprismatic)구조를 가지고 있다.

• 한국식품영양과학회지
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• 제41권3호
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• pp.310-319
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• 2012

본 연구에서는 기능적 특성이 우수한 우유 단백질 소재를 개발하여 식품산업에 응용하고자 우유 ${\alpha}$-La의 영양생리학적 특성에 대하여 분석하였다. 우유 ${\alpha}$-La의 기능성을 향상 시키려는 시도로써 MTGase의 첨가가 이 단백질의 이화학적 및 면역학적 특성에 미치는 영향을 조사하고, 수종의 암세포주의 생육에 대한 억제 효과를 탐색하였으며, ${\alpha}$-La의 구조적 상태에 따라 항암활성의 관련성을 검토하였다. ${\alpha}$-La에 반응한 MTGase에 의해 생성된 중합체는 인체 내 가수분해효소에 의해 분해가 용이한 것으로 확인되었다. 위암 세포주에 ${\alpha}$-La을 10 mg/mL 농도로 처리한 경우 높은 세포독성을 나타냈다. ${\alpha}$-La과 올레산의 복합체인 BAMLET은 간암 세포주에서 ${\alpha}$-La에 비해 더 강한 활성을 보였다. BAMLET은 apo 상태로 상당량의 이차구조를 지니고 있지만, 소수성 중심부는 느슨하게 형성된 MG와 같은 형태를 지니고 있을 것으로 추정되었다. NMR 분석 결과, BAMLET은 1.2 ppm과 0.8 ppm에서 지방산 보조인자인 올레산과 상호 작용하는 것으로 분석되었다.

• 한국결정성장학회지
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• 제5권3호
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• pp.233-239
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• 1995

$La_{1/3}NbO_3$와 $La_{1/3}TaO_3$의 대형 단결정을 적외선 용융대역법으로 제작하여 A-자리 공공이 유전 특성에 미치는 영향에 대하여 조사하였다. Weissenberg 및 Precession 사진에서 $La_{1/3}TaO_3$ 결정의 대칭성은 tetragonal 이며, 격자정수는 a $\approx$ 0.397, b $\approx$ 0.397, c $\approx$ 0.775이다. 유전이상은 $2/3La^{3+}$ 이온이 공공자리로의 이동에 기인한 것으로 추측하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.701-704
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• 2001

The dielectric and sintering properties of LaAlO$_3$ceramics synthesised with La$_2$O$_3$-Al$_2$O$_3$(LAO) and La$_2$O$_3$-Al(OH)$_3$(LAH) were investigated. In case of LAH samples, a single phase of LaAlO$_3$powders was formed at 100$0^{\circ}C$, density of the ceramics sintered at 140$0^{\circ}C$ was 6.41g/㎤, and the dielectric constant and loss were 22.4 and 0.003, respectively. In case of LAO samples, a single phase of LaAlO$_3$powders was formed at 130$0^{\circ}C$, density of the ceramics sintered at 150$0^{\circ}C$ was 6.35g/㎤, and the dielectric constant and loss were 22.16 and 0.009, respectively.

• 한국분말재료학회지
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• 제8권3호
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• pp.201-206
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• 2001

$>LaMnO_3$$(La, Sr)MO_3$, and $(La, Sr)MO_3/YSZ$ gel films were deposited by spin-coating technique on scandium-doped zirconia (YSZ) substrate using the precursor solution prepared from $La(O-i-C_3H_7)_3$, $Co(CH_3COO)_2$or $Mn(O-i-C_3H_7)_2$,2-methoxyethanol, and polyethylene glycol. By heat-treating the gel films, the electrochemical cells, $(La, Sr)MnO_3{\mid}ScSZ{\mid}Pt$ were fabricated. The effect of polyethylene glycol on the microstructure evolution of $$LaCoO_3and $LaMnO_3$thin films was investigated, and NOx decomposition characteristics of the electrochemical cells were investigated at $500^{\circ}C$ to $600^{\circ}C$. By applying a direct current to the $(La, Sr)MnO_3{\mid}ScSZ{\mid}Pt$ electrochemical cell, good NOx conversion rate could be obtained relatively at low current value even if excess oxygen is included in the reaction gas mixture.

• 한국재료학회지
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• 제7권12호
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• pp.1058-1062
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• 1997

강유전체 전계효과를 관찰하기 위해 LaCoO$_{3}$/Pb(Zr, Ti)O$_{3}$(La, Sr)CoO$_{3}$ 다층구조를 LcOo$_{3}$가 기판 위에 pulsed laser deposition(PLD)법으로 에피택셜하게 성장시켰다. 이러한 다층구조에서는 전도성 채널층으로 Si대신 반도성 LaCoO$_{3}$가 사용 되었다. LaCoO$_{3}$(LCO)의 비저항은 산소 분위기에 의하여 변화되었는데 특히 증착시 산소 분위기에 의존함을 보였다. LCO의 비저항은 0.1-100Ωcm범위에서 변화되었다. LCO층에 유도되는 강유전체 전계효과는 Pb(Zr, Ti)O$_{3}$(PZT)의 분극 상태에 따른 LCO의 저항 변화를 측정함으로써 관찰되었는데 1020$\AA$ 두께를 가진 LCO층에서는 4%의 저항 변화를 얻었으며 680$\AA$의 LCO에서는 9%의 증가된 저항 변화를 얻었다. DC 바이어스(-5V)를 가한 후에는 저항 변화가 45%까지 증가하였다. 이러한 결과는 적당한 비저항을 갖는 LCO를 사용한 LCO/PZT/LSCO다층구조가 강유전체 전계효과 트랜지스터로 사용될 수 있다는 가능성을 제시하고 있다.

• 한국전기전자재료학회논문지
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• 제11권11호
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• pp.969-974
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• 1998

The effects of $La_2O_3$on the microstructure and electrical characteristics of Pr-based ZnO varistors were investigated. The average grain size increased in the range of 21.9~56.3$\mu$ m with increasing $La_2O_3$additive content(0.0~2.0 mol%). La was, of course grain boundary, largely segregated at the nodal point. As $La_2O_3$additive content increases, threshold voltage and nonlinear coefficient decreased and leakage current increased. In particular, 2.0 mol% $La_2O_3$-added varistor exhibited low threshold voltage 17.0V/mm and nonlinear coefficient of about 6. Based on these results, this varistor can be said to be used as low-voltage varistor, if nonlinear coefficient is somewhat improved forward.