• 한국초지조사료학회지
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• 제38권3호
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• pp.175-179
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• 2018

Humic substances that can be obtained from coal resources such as leonardite in a bulk scale have been employed as crop stimulators and soil conditioners. The polymeric organics containing a variety of aromatic and aliphatic structures are known to activate plants in a multifunctional way, thus resulting in enhanced germination rate and abiotic stress resistance concomitant with induction of numerous genes and proteins. Although detailed structural-functional relationship of humic substances for plant stimulations has not been deciphered yet, cutting-edge analytical tools have unraveled critical features of humic architectures that could be linked to the action mechanisms of their plant stimulations. In this review article, we introduce key findings of humic structures and related biological functions that boost plant growth and abiotic stress resistance. Oxygen-based functional groups and plant hormone-like structures combined with labile and recalcitrant carbon backbones are believed to be critical moieties to induce plant stimulations. Some proteins such as HIGH-AFFINITY $K^+$ TRANSPORTER 1, phospholipase A2 and $H^+$-ATPase have been also recognized as key players that could be critically involved in humic substance-driven changes in plant physiology.

• 한국도서관정보학회지
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• 제39권4호
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• pp.377-395
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• 2008

본 연구의 목적은 Burton & Kebler의 문헌이용률 감소법칙을 적용하여 과학기술분야 학술잡지의 이용가능기간 즉 시간이 경과함에 따른 이용확률을 밝혀냄으로써 과학기술분야 잡지의 가치를 측정하고, 도서관이 이용자가 필요로 하는 정보를 제공하기 위해서는 어떤 잡지의 무슨 연도, 무슨 권호까지 소장해야 하는가를 결정하는데 도움이 되고자 하는 것이다. 국내 연구자들이 1991-2005년(15년간) 동안에 SCI 학술지에 발표한 과학기술분야 논문 126,425편 중에서 인용문헌 2,351,419건을 대상으로 과학기술 4개 주제(수학 4개, 물리학 12개, 화학 12개, 공학 14개)분야로 나누어 분석하였다. 분석 결과, 인용나이는 수학이 20-29년, 물리학, 화학, 공학이 각각 8-11년이었다. 평균 반감기는 수학이 11.22년, 물리학이 7.5년, 화학이 8.4년, 공학이 8.88년이었다.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.833-838
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• 2014

The energy- and time-dependent branching to the competing dissociation paths are studied by theory for coupled unimolecular dissociations of the o-, m-, and p-chlorotoluene radical cations to $C_7{H_7}^+$ (benzylium and tropylium). There are four different paths to $C_7{H_7}^+$, three to the benzylium ion and one to the tropylium ion, and all of them are coupled together. The branching to the multiple paths leads to the multiexponential decay of reactant with the branching ratio depending on both internal energy and time. To gain insights into the multipath branching, we study the detailed kinetics as a function of time and internal energy on the basis of ab inito/RRKM calculations. The number of reaction steps to $C_7{H_7}^+$ is counted for each path. Of the three isomers, the meta mostly goes through the coupling, whereas the para proceeds with little or no coupling. In the beginning, some reactants with high internal energy decay fast to the benzylium ion without any coupling and others rearrange to the other isomers. Later on all three isomers dissociate to the products via long-lived intermediates. Thus, the reactant shows a multiexponential decay and the branching ratio varies with time as the average internal energy decreases with time. The reciprocal of the effective lifetime is taken as the rate constant. The resulting rate-energy curves are in line with experiments. The present results suggest that the coupling between the stable isomers is thermodynamically controlled, whereas the branching to the product is kinetically controlled.

• 공업화학
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• 제20권6호
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• pp.593-602
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• 2009

오랫동안 슈퍼옥사이드 음이온 라디칼(superoxide anion radical)은 활성산소(reactive oxygen species, ROS) 화학종으로서 물리화학적 기초 연구에서부터 생명과학(혹은 생명공학) 분야에 이르기까지 상당한 관심의 대상이었다. 최근에는 고도산화공정(advanced oxidation processes, AOP, 혹은 advanced oxidation technologies, AOT)을 이용하는 오염물 제어 분야뿐만 아니라 나노물질에 의한 유해성을 평가하는데 있어서 슈퍼옥사이드 음이온 라디칼이 중요한 화학종으로 주목을 받고 있다. 그럼에도 불구하고 슈퍼옥사이드 음이온 라디칼에 대한 명확한 이해가 부족하여 관련 연구자들 사이에서 불필요한 논쟁과 혼동을 일으키고 있으며 슈퍼옥사이드 음이온 라디칼의 물리화학적 성질에 대한 오해를 가중시키고 있다. 이 글에서는 기존 연구에서 행해진 슈퍼옥사이드 음이온 라디칼의 물리화학적 특성 및 그 반응성에 대해 정리하였고 고도산화공정, 나노물질 및 생명공학 분야 등에서 슈퍼옥사이드 음이온 라디칼이 갖는 중요성을 서술하였다.

• 셀메드
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• 제5권3호
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• pp.17.1-17.22
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• 2015

Apart from being used as food, seed oils have also been used traditionally as medicinal products by several communities. However, the full medicinal potential of many seed oil plants is yet to be properly reviewed, particularly for their antimicrobial and antioxidant properties. North-East India has rich resources of seed oil plants. The availability of detailed information on these plants is quite limited. This review aims to explore and evaluate these seed oil plants of the North-East India with particular emphasis on their antimicrobial and antioxidant activities as well as chemical compositions. A comprehensive literature search on seed oil plants of this region has been performed. Seed oil yielding plants of this region can be categorized into two categories: plants that are used traditionally as sources of edible or medicinal oils and plants that are used for purposes other than as sources of oils. Many seed oil plants of this region have been reported to possess antimicrobial and antioxidant properties, and to produce various types of compounds. This review also highlights the importance of these plants in contributing to the local as well as the national economy of India.

• Journal of Microbiology and Biotechnology
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• 제28권12호
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• pp.2106-2112
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• 2018

Concanavalin A (ConA) interacts with carbohydrates as a lectin, and recent reports proposed its application for detecting a diversity of viruses and pathogens. Structural studies have detailed the interaction between ConA and carbohydrates and the metal coordination environment with manganese and calcium ions (Mn-Ca-ConA). In this study, ConA was crystallized with a cadmium-containing precipitant, and the refined structure indicates that $Mn^{2+}$ was replaced by $Cd^{2+}$ (Cd-Ca-ConA). The structural comparison with ConA demonstrates that the metal-coordinated residues of Cd-Ca-ConA, that is Glu8, Asp10, Asn14, Asp19, and His24, do not have conformational shifts, but residues for sugar binding, including Arg228, Tyr100, and Leu99, reorient their side chains, slightly. Previous studies demonstrated that excess cadmium ions can coordinate with other residues, including Glu87 and Glu183, which were not coordinated with $Cd^{2+}$ in this study. The trimeric ConA in this study coordinated $Cd^{2+}$ with other residues, including Asp80 and Asp82, for complex generation. The monomer does not have specific interaction near interface regions with the other monomer, but secondary cadmium coordinated with two aspartates (Asp80 and Asp82) from monomer 1 and one aspartate (Asp16) from monomer 2. This study demonstrated that complex generation was induced via coordination with secondary $Cd^{2+}$ and showed the application potential regarding the design of complex formation for specific interactions with target saccharides.

• Natural Product Sciences
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• 제13권3호
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• pp.214-219
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• 2007

The roots of Pseudarthria viscida (L.) Wight and Arnott. (Leguminosae) are used against various disorders in Indian systems of medicine, namely as anthelmintic, anti-inflammatory, cardiotonic, aphrodisiac, rejuvenating, tonic and as a remedy for cough, asthma, tuberculosis, diarrhoea and alternate fever. The present communication deals with the detailed pharmacognostical evaluation of the root sample using light and confocal microscopy, WHO recommended physico-chemical determinations and authentic phytochemical procedures. he physico-chemical, morphological and histological parameters presented in this paper may be proposed as parameters to establish the authenticity of P. viscida root and may possibly help to differentiate the drug from its other species.

• Journal of Mechanical Science and Technology
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• 제15권4호
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• pp.510-521
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• 2001

A nonlinear acoustic instability of subcritical liquid-oxygen droplet flames burning in gaseous hydrogen environment are investigated numerically. Emphases are focused on the effects of finite-rate kinetics by employing a detailed hydrogen-oxygen chemistry and of the phase change of liquid oxygen. Results show that if nonlinear harmonic pressure oscillations are imposed, larger flame responses occur during the period that the pressure passes its temporal minimum, at which point flames are closer to extinction condition. Consequently, the flame response function, normalized during one cycle of pressure oscillation, increases nonlinearly with the amplitude of pressure perturbation. This nonlinear response behavior can be explained as a possible mechanism to produce the threshold phenomena for acoustic instability, often observed during rocket-engine tests.

• 한국자동차공학회논문집
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• 제13권3호
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• pp.74-79
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• 2005

The Homogeneous Charge Compression Ignition(HCCI) combustion is currently under intensive investigation because of its potential to increase thermal efficiency while greatly decreasing NOx and p.M. In order to account for the thermal boundary layer effects, the two-zone model has been developed to analyze the combustion characteristics of HCCI engine. The detailed chemistry are represented by the GRI mechanism 3.0 involving 53 species and 325reactions. The present combustion model has been validated against the experimental results. Computations are also made for the wide-range operating conditions of HCCI engine.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.511-514
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• 2011

The impact of greenhouse gas (GHG) emissions is the global issue over the world. Korean government has presented various policies to induce GHG reduction for the industries with high energy consumption such as power generation and chemistry. Construction sector has produced a large amount of GHG emissions resulted in the energy consumption of heavy equipments and the use of materials. This study aims to suggest the QA (Quality Assurance) and QC (Quality Control) method to identify and quantify the GHG emissions released from heavy equipments in the railroad construction sector. Generally, the accuracy and reliability of GHG inventory is dependent on the data collection. Therefore, it is necessary to mange the detailed statements for the fuel consumption of heavy equipments and the quantity of work in the field. Also, the breakdown of GHG emission sources should be recorded from the design step of railroad infrastructures. Based on these data, the GHG reduction technologies and polices can be applied in railroad construction sector.