• Title/Summary/Keyword: ${\chi}$ phase

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Isolation and Quantitative Determination of Patchouli alcohol from Pogostemon cablin Benth. (광곽향(Pogostemon cablin Benth.)으로부터 Patchouli alchol의 분리 및 함량분석)

  • Kim, Ju-Sun;Chi, Hyung-Joon;Won, Do-Hee;Kang, Sam-Sik
    • Korean Journal of Pharmacognosy
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    • v.29 no.1
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    • pp.18-21
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    • 1998
  • A method for isolation and quantitative determination of patchouli alcohol from Pogostemonis Herba (Pogostemon cablin) has been developed. Isolation of patchouli alcohol was achieved by column chromatography employing the normal-phase gradient separation system n-hexane-ether on silica gel column. The GC method for quantitative determination of patchouli alcohol provided a method for standardization of the raw drug. It suggested that the average content of patchouli alcohol in Pogostemonis Herba is about 0.26%.

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A Study on the Definition of Korean Medicine (한의학의 정의에 관한 연구)

  • Chi, Gyoo Yong
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.33 no.5
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    • pp.261-266
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    • 2019
  • In order to cope with various issues about access to public health system of Korean medicine and reformation of college curriculum and argument of pseudoscience on Korean medicine etc., a new definition of Korean medicine was devised. Two ways of approach were tried through analysis of precedent cases of definition on traditional medicine firstly and analysis on concept and logic of Korean medicine secondly. As a result, Korean medicine can be defined as a science of theories and application techniques for maintaining health and diagnosing, treating and preventing conditions、causes、prognosis of diseases or damages based on the correlative and complicated understanding about the structure and function of mind and body out of human lives under the environment and society. This definition can be used as a basis to derive legal rights or scope in area of research and education policies and social institutions of the Korean medicine and to confront scientification criticism hereafter.

Compact, Wavelength-selectable, Energy-ratio Variable Nd:YAG Laser at Mid-ultraviolet for Chemical Warfare Agent Detection

  • Kim, Jae-Ihn;Cho, Ki Ho;Lee, Jae-Hwan;Ha, Yeon-Chul
    • Current Optics and Photonics
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    • v.3 no.3
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    • pp.243-247
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    • 2019
  • We have developed a compact, wavelength-selectable, Q-switched Nd:YAG laser at mid ultraviolet for chemical warfare agent detection. The fundamental wave at 1064 nm is delivered by a pulsed solid state laser incorporating with a square-type Nd:YAG rod in a resonator closed by two crossed Porro prisms for environmental reliability. The output energy at 213 nm ($5{\omega}$) and 266 nm ($4{\omega}$) by ${\chi}^{(2)}$ process in the sequentially disposed BBO crystals are measured to be 6.8 mJ and 15.1 mJ, respectively. The output wavelength is selected for $5{\omega}$ and $4{\omega}$ by a motorized wavelength switch. The energy ratio of the $5{\omega}$ to the $4{\omega}$ is varied from 0.05 to 0.85 by controlling the phase matching temperature of the nonlinear crystal for sum-frequency generation without change of the output pulse parameters.

High throughput approaches to predicting drug absorption potential using the immobilized artificial membrane phosphatidylcholine column and molar volume

  • Yoon, Chi-Ho;Shin, Beom-Soo;Chang, Hyun-Sook;Yoo, Sun-Dong
    • Proceedings of the PSK Conference
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    • 2003.10b
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    • pp.239.2-239.2
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    • 2003
  • The purpose of this study was to evaluate the predictability of the fraction of drug absorbed in humans using the immobilized artificial membrane phosphatidylcholine column (IAMPC) under optimized conditions in comparison with a conventional IAMPC method. Twenty commercial drugs, both acidic and basic in nature, were used in the study, Drugs were dissolved in acetonitrile:water (50:50, v/v) at a concentration of 100 mg/ml, and were injected on HPLC/UVD at a mobile phase (acetonitrile:DPBS = 10:90,v/v) with a flow rate of 0.5 ml/min equilibrated at 37$^{\circ}C$. (omitted)

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Microwave Dielectric Characteristics of Ba(Mg1/3Nb2/3)O3-La(Mg2/3Nb1/3)O3 Ceramics with Crystal Structure (결정 구조에 따른 Ba(Mg1/3Nb2/3)O3-La(Mg2/3Nb1/3)O3세라믹스의 마이크로파 유전 특성)

  • Paik, Jong-Hoo;Lim, Eun-Kyeong;Lee, Mi-Jae;Jee, Mi-Jung;Choi, Byung-Hyun;Kim, Sei-Ki
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.1
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    • pp.30-37
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    • 2005
  • The microwave dielectric properties and their related structural characteristics in solid solutions of (1-$\chi$) Ba($Mg_{1/3}$Nb$_{2/3}$) $O_3$-$\chi$La(Mg$_{2/3}$Nb$_{1}$3) $O_3$(BLMN) have been investigated by measuring the dielectric constant($\varepsilon$r), Q value and temperature coefficient of resonant frequency($\tau$f) and by observing the crystal structure using high resolution transmission electron microscopy (HRTEM). Microwave dielectric properties showed characteristic features for specific composition. Dielectric constant($\varepsilon$$_{r}$) showed maximum value at the composition which corresponds to the phase boundary between 1 : 2 ordered and 1 : 1 ordered structure. The increase in $\varepsilon$$_{r}$ may be caused by the rattling of ions by incorporating smaller ions and the disordered structure. The variation of temperature coefficient of resonant frequency($\tau$$_{f}$) was investigated in terms of oxygen octahedra tilting.dra tilting.

Separation Characteristics of Ibuprofen in Kromasil HPLC Column (Kromasil HPLC 칼럼을 이용한 Ibuprofen의 분리특성 연구)

  • Park Joon Sub;Kim Byung Lip;Yoon Tae Ho;Kim In Ho
    • KSBB Journal
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    • v.20 no.3
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    • pp.244-249
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    • 2005
  • Chiral separation of racemic ibuprofen was achieved on a Kromasil KR100-5CHI-TBB column. Some chromatographic parameters (resolution, number of theoretical plates, HETP, capacity factor) are calculated under different separation conditions such as change of mobile phase compositions (hexane / t-BME : 85 / 15, 75 / 15, 65 / 35, 55 /45) as well as acetic acid concentrations for adjusting pH (0.1 to 1 $v/v\%$). Flow rate versus number of theoretical plates and HETP were compared to evaluate column efficiency. To determine the adsorption isotherms, PIM (Pulsed Input Method) was carried out. At concentrations of racemic ibuprofen between 0.1 and 0.3 mg/ml, S- and R-ibuprofen have the same retention time of 4.48 and 5.81 min. Ibuprofen isotherms show a linear form under concentrations of 0.3 mg/ml with eluent (hexane / t-BME = 55 / 45).

Synthesis, Structure and Magnetic Properties of Mn12 Single Molecule Magnet Containing 4-(Methylthio)benzoate as Peripheral Ligands

  • Lim, Jin-Mook;Do, Young-Kyu;Kim, Jin-Kwon
    • Bulletin of the Korean Chemical Society
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    • v.26 no.7
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    • pp.1065-1070
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    • 2005
  • $[Mn_{12}O_{12}(O_2CPh-4-SMe)_{16}(H_2O)_4]{\cdot}7CH_2Cl_2$ (1), a new single-molecule magnet complex has been successfully synthesized by substitution of acetate ligand of Mn12ac with 4-(methylthio)benzoic acid. Complex 1 crystallizes into triclinic P$\overline{1}$ with a = 18.321(3) $\AA$, b = 19.011(3) $\AA$, c = 27.230(4) $\AA$, $\alpha$ = 86.973(3)$^{\circ}$, $\beta$ = 76.919(3)$^{\circ}$, $\gamma$ = 87.613(3)$^{\circ}$, and Z = 2. In complex 1, one Mn(III) ion has an abnormal Jahn-Teller elongation axis oriented at an oxide ion. Complex 1 has two out-of-phase ac susceptibility peaks in the 2-4 K and 4-7 K regions. Effective anisotropy energy barrier and pre-exponential factor are $U_{eff}$ = 45.95 K, 1/$\tau$0 = 8.6 ${\times}\;10^9s^{-1}\;for\;{\chi}_M$'' peaks in the lower temperature region and $U_{eff}$ = 59.45 K, 1/$\tau_0$ = 2.2 ${\times}\;10^8\;s^{-1}$ for $\chi_M$'' peaks in the higher temperature region. The parameters of S = 10, g = 1.87, D = -0.40 $cm^{-1}$, and E = 0.00034 $cm^{-1}$ were obtained from the M/N${\mu}_B$ vs. H/T plot of complex 1.

Establishment of Rebar Quantity Estimation in BIM-based Initial Design Phase (BIM기반 초기 설계 단계 철근 물량 산출 프로세스 구축)

  • Song, Chi-Ho;Kim, Chee-Kyeong;Lee, Si Eun;Choi, Hyunchul
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.5
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    • pp.447-454
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    • 2016
  • In the meantime, looking at the present status of how to estimationte the quantity of rebar based on 3D BIM getting the limelight in these days, commercial BIM tools provide rebar modeling functions however it takes a vast amount of modeling time for modeling of rebar in use of that function hence there is no BIM software at present for practical use. Therefore, in this study, we organized and presented a practical rebar quantity estimationtion process in BIM-based design work-site and intended to develop a program named Rebar Automatic Arrangement Program - hereinafter called RAAP - which enables automatic rebar arrangement based on much more precise cross-sectional information of bars in column, beam, slab and wall than the one from existing 2D method under the conditions without any cross-sectional information in the initial design phase. In addition, we intended to establish rebar quantity estimationtion process in the initial design phase through interworking of modeling & quantity estimationtion functions in consideration of joint, anchoring length of BuilderHUB as a BIM software with RAAP. The results from this study are practical in developing a technology that is able to estimationte quantity with more improved reliability than the one from existing 2D-based methods with less effort when the quantity of framework is estimationted in the uncompleted state of cross-sectional design for structural members in the initial design phase of a construction project. And it is expected that it could be utilized as a basic study from which a reasonable quantity estimationtion program can be established in the initial design phase.

Study of Hydrotrope Action and Liquid Crystal Behavior of Concentrated Liquid Detergents (농축세정제의 액정 상거동과 하이드로트로프 작용에 대한 연구)

  • Chi, Gyeong-Yup
    • Applied Chemistry for Engineering
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    • v.27 no.5
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    • pp.516-520
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    • 2016
  • Concentrated liquid detergents have 2~3 times higher surfactant contents [35~45% (w/w)] compared to those of normal type detergents. In general, a single surfactant forms a lyotropic liquid crystal (LC) phase when the concentration is in the region of 30~60% (w/w). Whereas the concentrated liquid detergent at about 40% (w/w) concentration in a mixed surfactant system shows an opaque appearance of gel or LC. In order to meet consumer needs and preference for product appearance, we applied hydrotropes and various surfactants systems in concentrated liquid detergents to obtain an opaque gel-phase and also a clear transparent phase at even below zero $^{\circ}C$ temperature. The more effective hydrotropes for making concentrated liquid detergents are 1,6-hexanediol, adipic acid and dipropylene glycol (DPG) which have two hydrophilic groups in both terminated positions. In order to prepare an excellent concentrated liquid detergent, good hydrotropes alongside secondary type surfactants like LAS and SAS were used. The formation of LC phase of concentrated liquid detergents at about 40% (w/w) concentration could be prevented by the use of both hydrotropes and secondary type surfactants. The result indicate that concentrated detergents having excellent low temperature stability and controlled viscosity can be prepared.