• Bulletin of the Korean Chemical Society
• /
• 제19권3호
• /
• pp.340-344
• /
• 1998

A facile synthesis of 4,5-(1',2'-diphenylethylenedithio)-1,3-dithiole-2-thione (dPhEDT-DTT) is carried out via a Diels-Alder type [2+4] cycloaddition reaction of 1,3-dithiol-2,4,5-trithione oligomer and t-stilbene. Molecular structure of dPhEDT-DTT is determined by x-ray crystallography: space group P1, a=11.694(3) Å, b=12.117(3) Å, c=14.688(3) Å, α=113.12(2)°, β=102.23(2)°, γ=107.02(2)°, V= 1699.1(7) Å3, Z=2. It turns out that dPhEDT-DTT crystallizes as a racemic compound consisting of (R,R) and (S,S) enantiomers. Coupling reaction of dPhEDT-DTO undergone in neat P(OEt)3 yields TTF(SEt)4 instead of ET derivative. When PR3 (R=OEt, OPh, Ph) is used in benzene, toluene or xylene, however, dPhEDT-DTO is decomposed.

• 한국인구학
• /
• 제29권1호
• /
• pp.157-183
• /
• 2006

우리 사회에서 여성 고학력자의 취업 기회는 어떠한가? 이 연구는 여성 고학책자 혹은 전문 직종에서 여성 취업 기회에 대한 구체적인 이해를 위해 생화학이라는 최근 주목받고 있는 분야에서 여성 학위자의 교수 임용과 이에 영향을 주는 요인들을 분석했다. 지금까지 이 연구의 분석 결과를 요약하면 다음과 같다. 첫째, 박사 취득시 연령이 높을수록, 그리고 출생 코호트가 최근일수록 교수 임용 가능성이 높다. 특히 출생 코호트 분석을 통해서 시간이 지나면서 우리 사회에서 전반적인 여성 지위 개선과 함께 최근 국공립여교수채용목표제와 같은 정책과 더불어 여성 교수 임용 가능성의 향상 가능성을 살펴보았다. 둘째, 이 연구는 지금까지 교수 임용에 대한 연구와 달리, 단지 연구 업적의 양이 아니라, 연구 업적의 발표 학술지 유형(science citation index 등재 학술지 여부), 경력기간 내에서의 발표시점, 그리고 업적의 질적 측면을 보여주는 인용 횟수를 구별해서 분석했다. 결과적으로 교수 임용에 유리한 결과를 주는 것은 대학원 재학 시기에는 등재지에 실린 논문의 인용 횟수이고, 졸업 후 시기에는 등재지 논문 수라는 것을 제시했다. 이는 교수 임용 과정에서 해당 학자 평가 과정이 복합적으로 이루어진다는 것을 나타낸다. 이 연구는 앞으로 여성 학자의 교수 임용 기회향상을 위한 방안을 마련하기 위해서 학자에 대한 평가가 이루어지는 과정에 대한 다차원적인 분석틀이 필요하다는 것을 제시한다.

• 기술혁신연구
• /
• 제7권1호
• /
• pp.124-150
• /
• 1999

This study examines the personal characteristics, organizational attitudes, technical performances, and reward preferences of R&D professionals with Ph.D. degree in large private companies in Korea. Based on survey data from 887 professionals in nine different R&D organizations, the following results are found; 1) R&D professionals with Ph.D. degree exhibit higher autonomy preference, need for achievement, self-efficacy, technical career orientation, and performance proficiency than other R&D professionals; 2) As their organizational tenure increases, performance proficiency and transfer career orientation increases but their socialized level of organizational goals and values does not change; 3) They produce more technical publications and exhibit more positive organizational attitude than other R&D professionals; 4) They are more likely to prefer job content, professional, and job security rewards. These empirical findings suggest several theoretical and practical implications for the management of R&D professionals with Ph.D. degree in the large Korean firms.

• BMB Reports
• /
• 제54권2호
• /
• pp.112-117
• /
• 2021

Phospholipase D2 (PLD2) has been implicated in the tyrosine kinase-mediated signaling pathways, but the regulation events are yet to be identified. Herein, we demonstrate that pleckstrin homology (PH) domain of PLD2 (PLD2-PH) exerts an antitumorigenic effect via the suppression of PLD2 and focal adhesion kinase (FAK). The kinase domain of FAK interacts with PLD2-PH and induces tyrosine phosphorylation and activation of PLD2. Furthermore, PLD2 increased tyrosine phosphorylation of FAK. However, ectopic expression of the PLD2-PH competes for binding to FAK and reduces the interaction between PLD2 and FAK, thereby suppressing FAK-induced PLD activation and tyrosine phosphorylation of FAK. The PLD2-PH suppressed the migration and invasion of glioblastoma cells, as well as tumor formation in a xenograft mouse model. This study uncovers a novel role of PLD2-PH as a negative regulator of PLD2 and FAK.

• 한국기계가공학회지
• /
• 제17권2호
• /
• pp.83-88
• /
• 2018

Additive manufacturing (AM) technologies have attracted wide attention as key technologies for the next industrial revolution. Among AM technologies using various materials, powder bed fusion (PBF) processes and direct energy deposition (DED) are representative of the metal 3-D printing process. Both of these processes have a common feature that the laser is used as a heat source to fabricate the 3-D shape through melting of the metal powder and solidification. However, the material properties of the deposited metals differ when produced by different process conditions and methods. 17-4 precipitation-hardening stainless steel (17-4PH SS) is widely used in the field of aircraft, chemical, and nuclear industries because of its good mechanical properties and excellent corrosion resistance. In this study, we investigated the differences in microstructure and mechanical properties of deposited 17-4PH SS by PBF and DED processes, including the heat treatment effect.

• 한국해양공학회지
• /
• 제3권2호
• /
• pp.535-535
• /
• 1989

• 한국광학회:학술대회논문집
• /
• 한국광학회 2007년도 하계학술발표회 논문집
• /
• pp.319-320
• /
• 2007

We report on the fabrication of two-dimensional Silicon On Insulator (SOI) photonic crystal (PhC) superprism. To optimize the design of 2-D SOI PhC superprism, the photonic band structures (TE-polarization) for triangular lattices and the dispersion surfaces were calculated and analyzed by the plane wave expansion method. Dense 2-D SOI PhC superprism nanostructures with taper input and output waveguide microstructures were successfully fabricated by nanoimprint lithography, followed by inductively coupled plasma (ICP) etching.

• Restorative Dentistry and Endodontics
• /
• 제23권1호
• /
• pp.269-277
• /
• 1998

This in vitro study compared the microleakage of 4 lining conditions when used with Gallium alloy GF II and Valiant PhD. Class V cavity was prepared on both buccal and lingual surface of 80 extracted human premolar & molar teeth with one margin in enamel and another in dentin. Before restoration, prepared cavities were applied to no-liner, cavity varnish, Scotchbond multipurpose, and Superbond D-liner II plus according to manufacture's instructions. The restored teeth were stored in saline for 1 week, then thermocycled for 100 times, stained with 0.5% basic fuchsin dye for 1 day, sectioned, and observed using a light microscope. Following results were obtained. 1. The leakage value of Superbond-lined group showed significantly lower than that of nolined group on both margins of Valiant PhD(p<0.05). 2; There was no significant difference between the 4 lining conditions in Gallium alloy GF II (p>0.05). 3. When We make a comparison between Gallium alloy GF II and Valiant PhD under same lining conditions, the microleakage value of Gallium alloy GF II showed lower than that of Valiant PhD on occlusal & gingival margin(p<0.05) except for Superbond-lined group(p>0.05).

• 보존과학연구
• /
• 통권19호
• /
• pp.3-22
• /
• 1998

The effect of pH on degradation of paper by some fungi, which able to degrade cellulose, was investigated. Trichoderma koningii, Aspergillus nigerand Penicillium nigulosum were cultured at $28^{\circ}C$ for 16 days in the selective medium (PH3, PH4, PH5, PH6, PH7, PH8, PH9, PH10, PHC) containing paper as substrate. Each paper was pretreated with each pH buffer (pH 3∼pH 10, D.W.)prior to addition to the selective medium. Enzyme activities in the each culture medium were measured spectroph to metrically using C.M.C., Avicel, PNPG as the substrates for endoglucanase, exoglucanase and $\beta$-glucosidase, respectively. In all experimental fungi, the enzyme activities of PH3 and PH9 medium were usually much higher than those of other experimental groups. However in the PH6medium, enzyme activity was lower than other groups. To analyze the concentration and pattern of protein in the each culture medium, the medium was concentrated by lyophilization. The protein concentration of PH3 and PH9 medium were relatively high (T.koningii; 6.31mg, 6,19mg, A.niger; 1.62mg, 1.96mg, P.nigulosum;2.50mg, 2.73mg, respectively), but that of PH6 was relatively low. The protein pattern of each medium was analyzed by using SDS-PAGE and VDS Image Master Analysis Program. The concentrations of bands in the each lane were usually high at lane2 (PH3) and lane8 (PH9) and low at lane5 (PH6). Therefore, the incresed cellulolytic activity of fungus against acidified paper could be result of structural change and deterioration of paper caused by being acidified.

• 유통과학연구
• /
• 제21권4호
• /
• pp.47-56
• /
• 2023

Purpose: the research aims to analyze the impact of the distribution of knowledge through online learning on the intellectual potential of PhD students and produce recommendations for policy to improve intellectual capacity. During the literature review, it was determined that a large number of studies examined the impact of online learning on the quality of education at different levels. Research design, data and methodology: the research methodology is based on subjective assessment and studying the students' opinions. The basis of the study was a comprehensive analysis of primary data obtained through a sociological survey of PhD students. 324 respondents from humanitarian, medical and natural faculties participated in the survey. Results: the study revealed that online learning helps increase students' intellectual potential. PhD students had a positive attitude towards the transition from traditional education to online learning. It should be noted that, according to the results, the most popular gadgets were laptops and smartphones, which were characterized by high mobility and ease of use. Based on the obtained results, recommendations were developed for the formation of online learning with a focus on increasing students' intellectual potential. Conclusions: based on the results of the assessment of educational and innovative potential, policy recommendations and further research in this area were proposed.