• 제목/요약/키워드: Model compound

검색결과 876건 처리시간 0.031초

Mechanisms of Lignin Biodegradation by Ligninase, Phanerochaete Chrysosporium Burds

  • Hwang, Byung-Ho
    • Journal of Forest and Environmental Science
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    • 제6권1호
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    • pp.45-60
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    • 1989
  • 리그닌 생분해의 분해경로 및 매카니즘에 관한 연구가 최근 Kirk와 Higuchi 등에 의하여 활발히 연구되고 있다. 특히, Phanerochaete chrysosporium이 생산해내는 Lignlnase를 이용하여 매우 가치있는 연구 결과를 얻고 있다. 본 총설에서는 Kirk와 Higuchi의 허가를 얻어서 그들의 논문을 중심으로 리그닌의 중요한 결합 양식 별로 즉, ${\beta}$-O-4, ${\beta}$-5, ${\beta}$-1, ${\beta}$-6, 5-5 등의 결합 모델 화합물들의 분해경로 및 매카니즘에 관하여 조사 정리하였다.

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Synthesis and Cyclization of Aromatic Polyhydroxyamides. 1. Model Compound Study

  • Kim, Hae-Young;Kim, Myung-Kyoon;Baik, Doo-Hyun;Simon Kantor
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 1998년도 가을 학술발표회논문집
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    • pp.37-40
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    • 1998
  • Aromatic polybenzoxazoles have been known since 1964 as a class of aromatic heterocyclic polymers that exhibit excellent thermal stability. Polyhydroxyamides (PHA), precursor polymers to PBO, can cyclize to farm stable heterocyclic polymers with the simultaneous release of small molecules, which can be expected to act as a fire quencher. (omitted)

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Active/Reactive Compound Compensation in Distribution System

  • Sul, Yong-Tae
    • Journal of Electrical Engineering and information Science
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    • 제2권4호
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    • pp.46-52
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    • 1997
  • In this paper th use of compensation based on a combination of active plus reactive power at distribution model system is proposed. The basic voltage-power relationships for the linearized case on an infinite bus are used and the compensation angle is defined based on the voltage magnitude response to small power injection. Compensation is supplied at several locations, and the system is subjected to varying fault scenarios, with its response observed under different system conditions. As number of control issues for a storage-based active/reactive power compensator as a bus voltage regulator are explored to compare the effectiveness of active/reactive again reactive-only compensation.

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The Bonding of Interstitial Hydrogen in the NiTi Intermetallic Compound

  • Kang, Dae-Bok
    • Bulletin of the Korean Chemical Society
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    • 제27권12호
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    • pp.2045-2050
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    • 2006
  • The interstitial hydrogen bonding in NiTi solid and its effect on the metal-to-metal bond is investigated by means of the EH tight-binding method. Electronic structures of octahedral clusters $Ti_4Ni_2$ with and without hydrogen in their centers are also calculated using the cluster model. The metal d states that interact with H 1s are mainly metal-metal bonding. The metal-metal bond strength is diminished as the new metal-hydrogen bond is formed. The causes of this bond weakening are analyzed in detail.

PHA 및 그 유도체의 열적 고리화 거동 고리화 거동(I) - 모델화합물 연구 - (Thermal Cyclization of PHA and its Derivatives(I) - Model compound study -)

  • Kim, Eun-Kyoung;Kim, Myung-Kyoon;Baik, Doo-Hyun
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 2001년도 가을 학술발표회 논문집
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    • pp.361-363
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    • 2001
  • Aromatic pelybenzoxazoles(PBOs) display excellent thermal stability plus good solvent and chemical resistance. Wholly aromatic PBOs, in fact, are soluble only in strong acids(e.g., sulfuric, rmethanesulfonic, triflic, and polyphosphoric acids). However, fully heterocyclized polymers have shown some drawbacks in solubility and processing. This problem of processing is currently being exploited to obtain unusual combinations of physical properties in fibers and films. (omitted)

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명사 brigram 모델을 이용한 한국어 복합명사 분해 (Korean Compound Noun Decomposition using Noun Bigram Model)

  • 강민규;강승식
    • 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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    • 한국정보과학회언어공학연구회 2010년도 제22회 한글 및 한국어 정보처리 학술대회
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    • pp.9-14
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    • 2010
  • 본 논문에서는 명사의 띄어쓰기 bigram과 단일명사 정보를 이용하여 복합명사를 분해하는 방법을 제시한다. 붙여쓰기와 띄어쓰기를 모두 허용하는 복합명사의 특징에 따라 띄어쓰기 bigram으로 후보를 선정할 경우, 분해시간과 후보의 수를 크게 줄일 수 있으며, 긴 음절의 복합명사도 bigram의 chain을 통해 빠르게 후보 조합이 가능하다. 분해 후보가 복수일 경우, 명사 간 bigram 확률을 계산하여 최적의 분해 후보를 선정한다.

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The Photoaddition Reaction of 1,4-Diphenyl-1,3-butadiyne with 5-Fluorouracil

  • Shim, Sang-Chul;Lee, Tae-Suk;Kim, Sung-Sik
    • Bulletin of the Korean Chemical Society
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    • 제7권3호
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    • pp.228-230
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    • 1986
  • Diacetylene compound, 1,4-diphenyl-1,3-butadiyne, was photolyzed with 5-fluorouracil as a model reaction of the phototoxic conjugated poly-ynes with DNA or RNA and obtained a [2 + 2] photocycloadduct. The structure of the photoadduct was determined by spectral methods and compared with the [2 + 2] photoadducts of 1,4-diphenyl-1,3-butadiyne with tetramethylethylene and dimethyl fumarate.

RBL-2H3 비만세포와 동물병태모댈에서 소청룡탕(小靑龍湯)의 항알레르기 효과 (Anti-allergic Effects of Socheongyoug-tang on RBL-2H3 Mast Cell and Mice-mediated Allergy Model)

  • 김경렬;이종화;김영준;최성열;김태헌;류영수;강형원
    • 동의생리병리학회지
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    • 제21권5호
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    • pp.1260-1270
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    • 2007
  • The discovery of drugs on the treatment of mast cell-mediated allergic disease is a very important subject in human heath. The Socheongyoug-tang(SCYT) has been used for centruries as a traditional medicine in Korea and is known to have an anti-inflammatory effect. However, its specific mechanism of action is still unknown. In this report, we investigated the effect of hot water extract from SCYT on RBL-2H3 mast cell-mediated allergic reaction and studied its possible mechanism of action. SCYT inhibited compound 48/80-induced systemic anaphylaxis and serum histamine release in mice. SCYT decreased the passive cutaneous anaphylaxis reaction activated by Anti-lgE antibody-HSA. SCYT dose-dependently reduced histamine release from mice peritoneal mast cells activated by Anti-lgE antibody-HSA. SCYT increased cAMP and decreased compound 48/80-induced intracellular $Ca^{2+}$ levels. Our findings provide evidence that SCYT inhibits mast-derived allergic reactions, and also demonstrate the involvement of cAMP and intracellular $Ca^{2+}$ in these effects.

Near-Infrared Laser Stimulation of the Auditory Nerve in Guinea Pigs

  • Guan, Tian;Wang, Jian;Yang, Muqun;Zhu, Kai;Wang, Yong;Nie, Guohui
    • Journal of the Optical Society of Korea
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    • 제20권2호
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    • pp.269-275
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    • 2016
  • This study has investigated the feasibility of 980-nm low-energy pulsed near-infrared laser stimulation to evoke auditory responses, as well as the effects of radiant exposure and pulse duration on auditory responses. In the experiments, a hole was drilled in the basal turn of the cochlea in guinea pigs. An optical fiber with a 980-nm pulsed infrared laser was inserted into the hole, orientating the spiral ganglion cells in the cochlea. To model deafness, the tympanic membrane was mechanically damaged. Acoustically evoked compound action potentials (ACAPs) were recorded before and after deafness, and optically evoked compound action potentials (OCAPs) were recorded after deafness. Similar spatial selectivity between optical and acoustical stimulation was found. In addition, OCAP amplitudes increased with radiant exposure, indicating a photothermal mechanism induced by optical stimulation. Furthermore, at a fixed radiant exposure, OCAP amplitudes decreased as pulse duration increased, suggesting that optical stimulation might be governed by the time duration over which the energy is delivered. Thus, the current experiments have demonstrated that a 980-nm pulsed near-infrared laser with low energy can evoke auditory neural responses similar to those evoked by acoustical stimulation. This approach could be used to develop optical cochlear implants.