액정의 윤활제로서의 응용에 관한 연구

민지홍,임윤철 연세대학교 산업기술연구소 1991 논문집 Vol.23 No.1

The velocity and pressure field are analyzed numerically for the thin wedge type liquid crystal film. Galerkin's weighted residual method is employed to solve momentum and continuity equations. Two of the characteristics of liquid crystal, permeability and splay effect, are treated in terms of body force and are investigated as well as the effect of the dislocations of layered crystal. A plane slider bearing is chosen to evaluate the load characteristics when liquid crystal is applied as a lubricant. The bearing load is increased compared to the conventional hydrodynamic lubrication theory. Numerical results are obtained up to the dimensionless permeability 0.5 due to the numerical instability.

영어 사역동사 보충절의 통사구조

황규홍,민지영 東亞大學校 2005 東亞論叢 Vol.42 No.-

This paper aims to investigate the syntax of causative verb clausal complements of make, have, let, and help in English within the minimalist framework outlined in Chomsky (1999, 2000, 2001), by emphasizing their constituency and categorial status. Generally, those syntactic causative verbs select bare infinitives as their complements, even though help also exceptionally takes another type of complements : to-infinitives. I put forward the proposals: i ) such causative verb clausal complements are single constituents, by examining a variety of constituency tests : coordination, reflexives, and expletives, and ii ) their categories are TPs whose head T is defective, lacking ∮ -complete.

강상판교의 다단계 최적설계

조효남,정지승,민대홍 漢陽大學校 工學技術硏究所 1999 工學技術論文集 Vol.8 No.1

최근 도심지의 극심한 교통체증의 해소를 위한 방안으로 강상판교의 채택이 증가하고 있다. 그 주된 이유는 신속한 시공과 콘크리트덱에 비하여 자중의 감소효과가 크고 보다 큰 강도와 효율적인 가설이 가능하기 때문이다. 본 연구의 목적은 최적설계프로그램을 이용한 강상판교의 가장 합리적인 형식결정에 관한 연구이다. 최적화의 목적함수는 최소 초기비용으로 정식화하였다. 설계 제약조건은 도로교시방서의 ASD설계기준에 맞추어 정식화하였으며 최적설계과정은 두 단계로 이루어져 있다. 첫 번째 단계는 박스 또는 플레이트주형에 대한 강상판교의 최적설계가 수행된다. 그리고 두 번째 단계에서 개단면 또는 폐단면리브를 갖는 강상판에 대하여 최적설계를 한다. 최적설계 프로그램의 구조해석은 주형에 대하여 격자해석 모델링을 이용하였고 강상판에 대해서는 Pelican-Esslinger법을 사용하였다. 최적화 기법은 SQP를 이용하였다. 적용예의 각 형식별 강상판교의 최적설계 결과의 비교를 통하여 비용의 효율성을 검토하였고 폐단면리브를 가지는 직선 형상의 박스거더 형식이 가장 효율적이고 경제적으로 판단된다. Recently, more and more othotropic steel plate deck bridges have been adopted as a solution against traffic congestion in urban area, mainly because of fast construction, reduced self-weight, higher stiffness and efficient erection compared to that of concrete decks. The main objective is to study on the most effective optimal type and proportioning of a rational othotropic steel plate deck bridges. The objective function for the optimization is formulated as a minimum cost design problem. The behavior and design constraints are formulated based on the ASD criteria of the Korean Bridge Design Code. The optimum design program developed in this study consists of two steps - the first step for the optimization of the steel box or plate girder viaducts, and the second step for the optimum design of the steel-decks with closed or open ribs. A grid model is used as a structure analysis model for the optimization of the main girder system, while the analysis of the deck system is based on the Pelican-Esslinger method. The SQP(Sequential Quadratic Program) is used as the optimization technique for the constrained optimization. By using a set of application examples, the rational type related to the optimized steel-deck system designs is investigated by comparing the cost effectiveness of each type. Based on the results of the investigation it may be concluded that the optimal linear box girder and deck system with closed ribs may be utilized as one of the most rational and economical viaducts.

신뢰성 제약조건을 가지는 강상형교의 최적설계

조효남,정지승,민대홍 漢陽大學校 工學技術硏究所 1999 工學技術論文集 Vol.8 No.1

구조물의 설계에는 재료의 불확실성, 시공오차 등과 같은 많은 불확실량이 포함되어 있어서, 설계되는 구조물에 절대적인 안정성을 부여한다는 것은 어려우므로 구조물의 설계시 확률적인 방법을 이용해 체계적인 설계를 할 필요가 있다. 또한 점차로 구조설계의 불확실성에 대한 고려의 필요성이 널리 인식되어 가고있는 현실이다. 따라서 신뢰성에 기초한 최적설계는 실질적인 최적설계 결과를 위한 의미 있고 합리적인 접근이라 할 수 있다. 이에 본 논문에서는 허용응력설계법(ASD)과 하중저항계수법(LRFD) 그리고 신뢰성에 기초한 최적설계를 수행하였다. 그리고 이에 따른 각각의 결과치를 비교 검토함으로서 각 설계법에 대한 최적설계의 타당성 여부를 논의하였다. 방법론을 말하자면 신뢰성 해석 알고리즘에는 개선된 1계 2차모멘트법(AFOSM)을 적용하였고, 강상형교량의 한계상태모형은 von Mises 조합음력 기준을 근거로한 BS시방서 기준을 사용하였다. 신뢰성에 기초한 최적설계의 제약조건으로는 ASD 기준들을 근거로 하였고, ASD, LRFD에 기초한 최적설계는 각각의 설계기준 들을 근거로 하였다. LRFD의 경우, AASHOTO 와 도로교시방서 각각의 경우에 대하여 고려를 하였다 LRFD에 기초한 최적화결과는 ASD에 대한 최적치보다 경제적이며 신뢰성에 기초한 최적치와도 큰 차이가 없는 것으로 나타났다. The results of optimum design by the deterministic approach heavily depend upon the safety levels adopted in the current design codes. However, it is now generally recognized that structural design problems are non-deterministic and, thus, optimum structural design must cope with uncertainties involved in the design of structures. Therefore, it may be positively stated that reliability-based optimum design is more meaningful and rational approach to obtain a real optimum design solution. In the paper, a systematic procedure for reliability-based optimum design is presented as a rational approach for the optimum structural design of steel box girder bridges. Optimum design problems of steel box girder bridges are formulated respectively based on the ASD, LRFD and reliability constraints. An advanced first-order second moment method is used as a practical tool for the reliability analysis in the reliability-based optimization algorithm. Uncertainties in the structural strength and loading due to inherent variability as well as modeling and prediction errors are included in the failure limit state of combined bending and shear. For the more precise modelling of the optimization of continuous steel box girder bridges, an interactive non-linear limit state model is formulated based on the von Mises combined stress yield criterion. The ASD criteria are used for the optimum design of box girder bridges under reliability constraints whereas both ASD and LRFD criteria are used for the codified deterministic optimization. And then, this study comparatively shows the results of the optimum designs for various criteria of design codes. In addition, the results of reliability-based optimization are compared with those of codified optimizations. It has been observed that the LRFD-based optimization provides more economical results compared to the ASD-based optimization, while the reliability-based optimization is not significantly different from the LRFD-based optimization as expected.

Escherichia coli 패혈증 환자에 합병된 대칭적 하지 말단 괴사증 1예

남해성,유진홍,권순석,민준기,조현선,박민경,심병주,남유정,이지인,김진수,길욱현,조근종,신완식 대한감염학회 2005 감염과 화학요법 Vol.37 No.6

We have encountered a rare case of symmetrical peripheral gangrene complicating Escherichia coli sepsis in a 47-years-old male. He was successfully treated with antibiotics, anticoagulants, and vasodilator. To our knowledge, this is the first report on symmetrical peripheral gangrene complicating E. coli sepsis in Korea.

Hop Extract Produces Antinociception by Acting on Opioid System in Mice

Park, Soo-Hyun,Sim, Yun-Beom,Kang, Yu-Jung,Kim, Sung-Su,Kim, Chea-Ha,Kim, Su-Jin,Seo, Jee-Young,Lim, Su-Min,Suh, Hong-Won The Korean Society of Pharmacology 2012 The Korean Journal of Physiology & Pharmacology Vol.16 No.3

In the present study, the antinociceptive profiles of hop extract were characterized in ICR mice. Hop extract administered orally (from 25 to 100 mg/kg) showed an antinociceptive effect in a dose-dependent manner as measured in the acetic acid-induced writhing test. Antinociceptive action of hop extract was maintained at least for 60 min. Moreover, cumulative response time of nociceptive behaviors induced with intraplantar formalin injection was reduced by hop extract treatment during the 2nd phases. Furthermore, the cumulative nociceptive response time for intrathecal injection of substance P ($0.7{\mu}g$) or glutamate ($20{\mu}g$) was diminished by hop extract. Intraperitoneal pretreatment with naloxone (an opioid receptor antagonist) attenuated antinociceptive effect induced by hop extract in the writhing test. However, methysergide (a 5-HT serotonergic receptor antagonist) or yohimbine (an ${\alpha}_2$-adrenergic receptor antagonist) did not affect antinociception induced by hop extract in the writhing test. Our results suggest that hop extract shows an antinociceptive property in various pain models. Furthermore, the antinociceptive effect of hop extract may be mediated by opioidergic receptors, but not serotonergic and ${\alpha}_2$-adrenergic receptors.

대황의 항산화 효과 및 타이로시네이즈 저해 활성

김정은 ( Jung Eun Kim ),박찬하 ( Chan Ha Park ),오대석 ( Dae Seok Oh ),이승연 ( Seung Yeon Lee ),장세훈 ( Se Hun Jang ),홍지연 ( Jee Yeon Hong ),민혜진 ( Hye Jin Min ),박수아 ( Su Ah Park ),원두현 ( Doo Hyun Won ),박수남 ( Soo Nam 대한화장품학회 2011 대한화장품학회지 Vol.37 No.4

본 연구에서는 대황 추출물의 항산화 활성, 타이로시네이즈(tyrosinase) 저해 활성을 확인하였다. 대황의 50 % 에탄올 추출물, 에틸아세테이트(ethyl acetate) 분획, 아글리콘(aglycone) 분획으로 실험을 진행하였다. 대황 추출물들의 DPPH (1,1-diphenyl-2-picrylhydrazyl) 소거활성(FSC₅₀)은 대표적인 항산화제인 (+)-α-tocopherol보다 낮은 것으로 나타났다. Luminol 발광법을 이용한 Fe³⁺-EDTA/H₂O₂ 계에서 생성된 활성산소종에 대한 아글리콘 분획의 소거활성(총 항산화능, OSC₅₀)은 0.265 μg/mL로 매우 큰 활성을 나타내었다. 대황 추출물의 rose-bengal로 증감된 ¹O₂에 의한 적혈구 파괴에 대한 세포보호 효과는 모든 분획에서 농도 의존적(1∼50 μg/mL)으로 증가하였으며, 특히 아글리콘 분획은 10 μg/mL 농도에서 τ₅₀이 757.0 min으로 높은 세포 보호 활성을 나타내었다. 대황 추출물 중 아글리콘 분획의 타이로시네이즈 저해활성(IC₅₀)은 11.20 μg/mL으로 226.88 μg/mL인 알부틴(arbutin)보다 큰 활성을 보여주었다. 이상의 결과들로부터 대황 추출물은 활성산소종을 소거하는 항산화제로 이용가능하며, 특히 아글리콘 분획의 현저한 항산화 작용 및 큰 타이로시네이즈 저해 효과로부터 이들 분획 또한 화장품원료로서 응용 가능성이 큼을 알 수 있었다. In this study, the antioxidative effects and inhibitory activities on tyrosinase of Rheum undulatum (R. undulatum) L. extracts were investigated. 50 % ethanol extract, ethyl acetate and aglycone fractions of R. undulatum L. were used in experiments. The DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activities (FSC₅₀) of R. undulatum L. extracts was lower than (+)-α-tocopherol, known as a typical antioxidant. Reactive oxygen species (ROS) scavenging activities (OSC₅₀) of aglycone fraction on ROS generated in Fe³⁺-EDTA/H₂O₂ system using the luminol-dependent chemiluminescence assay showed the most prominent effect at a concentration of 0.265 μg/mL. The cellular protective effects of extract/fractions of R. undulatum L. on the rose-bengal sensitized photohemolysis of human erythrocytes were increased in a concentration dependent manner (1 ~ 50 μg/mL). Especially, aglycone fraction in 10 μg/mL concentration showed the most protective effect among extracts (τ₅₀, 757.0 min). The inhibitory effects (IC₅₀, 11.20 μg/mL) on tyrosinase of aglycone fraction was much higher than arbutin (226.88 μg/mL), known as a whitening agent. These results indicate that R. undulatum L. extracts can be used as antioxidant. Particularly, aglycone fraction of R. undulatum L. showed superior antioxdative activity and high inhibitory effect on tyrosinase. Therefore, aglycone fraction of R. undulatum L. could be applicable to new functional cosmetics.

Complete mitochondrial genome of Camponotus atrox (Hymenoptera: Formicidae): a new tRNA arrangement in Hymenoptera

Min Jee Kim,Eui Jeong Hong,Iksoo Kim 한국응용곤충학회 2015 한국응용곤충학회 학술대회논문집 Vol.2015 No.10

We sequenced the complete mitochondrial (mt) genome of Camponotus atrox (Hymenoptera: Formicidae) that is distributed only in Korea. This genome is 16,540 bp in size, contains typical sets of genes (13 protein-coding genes, 22 tRNAs, and two rRNAs). The C. atrox A+T-rich region is the longest in the sequenced ants as 1,402 bp and is comprised of an identical tandem repeat consisting of six 100-bp copies and one 96-bp copy. A total of 315 bp of intergenic-spacer sequences were spread over 23 regions. An attempt to align spacer sequences in ants turned out that alignment was mostly feasible among congeneric species, with a substantial sequence divergence, indicating the potential of these sequences as congeneric molecular markers. The A/T content in first and second codon positions of PCGs are similar in ants including C. atrox (73.9 vs. 72.3% on average). Estimation of degree of genetic divergence (e.g. non-synonymous substitution rate) with an increased taxon sampling among hymenopteran superfamilies indicated the presence of different rates of divergence between the suborders Symphyta and Apocrita as has previously been reported. The C. atrox mt genome has a unique gene arrangement, trnI-trnM-trnQ at the A+T-rich region and ND2 junction (underline for inverted gene), possibly originated from tandem duplication of trnM-trnI, resulting in trnM-trnI-trnM-trnI-trnQ and loss of first trnM and second trnI, resulting in trnI-trnM-trnQ.

Determination of the Absolute Configuration of Khellactone Esters from <i>Peucedanum japonicum</i> Roots

Hong, Min Jee,Kim, Jinwoong American Society of Pharmacognosy 2017 Journal of natural products Vol.80 No.5

<P>Sixteen new angular dihydropyranocoumarins.(1-16) and 24 known compounds were isolated from the roots of Peucedanum japonicum Thunb. The absolute configuration of diacylkhellactone was established by partial hydrolysis, the Mosher method, and X-ray crystallography. In addition, ECD spectroscopy was used to assign the absolute configurations of several of the angular dihydropyranocoumarins. Enantiomers were detected by RP-HPLC using MTPA esters while acyl migration of the substituents was observed in cis-monoacylkhellact ones.</P>

The Complete DNA Sequence and Genome Organization of the Mitochondrial Genome of the White-spotted Flower Chafer, Protaetia brevitarsis (Coleoptera: Cetoniidae)

Min Jee Kim,Mee Yeon Hong,Byung Rae Jin,Man Il Kim,Iksoo Kim 한국응용곤충학회 2009 한국응용곤충학회 학술대회논문집 Vol.2009 No.05

The complete nucleotide sequences of the mitochondrial genome (mitogenome) from the white-spotted flower chafer, Protaetia brevitarsis (Coleoptera: Cetoniidae) was determined. The 20,319-bp long circular genome is the longest among the completely sequenced arthropods. This extraordinary length of the genome stemmed from 5,654-bp long A+T-rich region composed of twenty-eight 117-bp tandem repeats, seven 82-bp tandem repeats, and each two 19-bp and 38-bp tandem repeats. The P. brevitarsis contains a typical gene complement, order, and arrangement identical to most common type found in insects. The P. brevitarsis COI gene does not have typical ATN codon. Thus, we also designated it as AAC (asparagine), which is found in the start context of all sequenced Polyphaga within Coleoptera. All tRNAs showed stable canonical clover-leaf structure of other mt tRNAs, except for tRNASer (AGN), DHU arm of which could not form stable stem-loop structure. The 5bp-long motif sequence (TAGTA) that has been suggested to be the possible binding site for the transcription termination peptide for the major-strand also was found betweent RNASer (UCN) and ND1, as have been detected in all sequenced coleopteran insects.