• Title/Summary/Keyword: $O(^1D_2)$

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Saponins from the Fructus of Kochia scoparia

  • Whang, Wan-Kyunn;Hahn, Dug-Ryong
    • Archives of Pharmacal Research
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    • v.14 no.2
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    • pp.176-180
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    • 1991
  • Two new triterpenoidal saponins B(1) and C(2) were isolated from the fructus of Kochia scoparia. On the basis of chemico-spectral evidences, the structures of 1 and 2 were elucidated as oleanolic acid 3-O-$\beta$-D-ribopyranosyl-(1$\rightarrow$2)-.betha.-D-glucuronopyranoside and 3-O-$\beta$-D-xylopyranosyl-(1$\rightarrow$3)-$\beta$-D-glucuronopyranosyl-olean-12-en-28-O-$\beta$-D-glucopyranosyl ester, respectively.

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A Finite Element Analysis of Elastomeric O-ring Performance and Structure when subjected to Foreign Objects (유한요소해석을 이용한 이물질이 고무오링과 구조물에 미치는 영향과 성능 연구)

  • Pack, Inseok;Rhee, Heejang;Lee, Seoksoon
    • Journal of Aerospace System Engineering
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    • v.11 no.1
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    • pp.28-34
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    • 2017
  • Elastomeric o-ring performance and structure when subjected to a foreign object is studied using finite element analysis (FEA). Elastomeric o-rings have been studied using 2D analysis for a long time. Contact pressure is an important factor in o-ring design. When contact pressure is lower than applied pressure, leaking, vibration, and noise can occur; resulting in decreased output. In this study, we compared 2D and 3D analyses of elastomeric o-rings. Similar results were shown for 2D and 3D contact pressure. However, when an o-ring encounters foreign object matter, 3D analysis is required because contact pressure in every direction needs to be considered. We determined the influence of foreign matter on o-ring performance and structure by analyzing 10 cases with different clearances in a 3D model. Therefore, an o-ring encountering foreign object matter must be analyzed in 3D with the result included in the o-ring design.

Isolation of Flavonoid Glycosides with Cholinesterase Inhibition Activity and Quantification from Stachys japonica

  • Nugroho, Agung;Choi, Jae Sue;Seong, Su Hui;Song, Byong-Min;Park, Kyoung-Sik;Park, Hee-Juhn
    • Natural Product Sciences
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    • v.24 no.4
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    • pp.259-265
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    • 2018
  • The three flavone glycosides, 4'-O-methylisoscutellarein 7-O-(6'''-O-acetyl)-${\beta}$-D-allopyranosyl(1${\rightarrow}$2)-${\beta}$-D-glucopyranoside (1), isoscutellarein 7-O-(6'''-O-acetyl)-${\beta}$-D-allopyranosyl(1${\rightarrow}$2)-${\beta}$-D-glucopyranoside (3), and isoscutellarein 7-O-${\beta}$-D-allopyranosyl(1${\rightarrow}$2)-${\beta}$-D-glucopyranoside (4) in addition to a flavonol glycoside, kaempferol 3-O-${\beta}$-D-glucopyranoside (astragalin, 2), were isolated from Stachys japonica (Lamiaceae). In cholinesterase inhibition assay, compound 1 significantly inhibited aceylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities ($IC_{50}s$, $39.94{\mu}g/ml$ for AChE and $86.98{\mu}g/ml$ for BChE). The content of isolated compounds were evaluated in this plant extract by HPLC analysis. Our experimental results suggest that the flavonoid glycosides of S. japonica could prevent the memory impairment of Alzheimer's disease.

A Novel 3D Polypseudo-rotaxane Metal-organic Framework Based on a Flexible Bis-pyridyl-bis-amide Ligand

  • Wang, Xiu-Li;Han, Na;Lin, Hong-Yan;Xu, Chuang;Luan, Jian;Liu, Guo-Cheng
    • Bulletin of the Korean Chemical Society
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    • v.33 no.11
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    • pp.3793-3796
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    • 2012
  • A novel 3D compound $\{[Cu(L)(H_2O)_4][Cu_2(SIP)_2(L)_2]\}{\cdot}2H_2O$ (1) (L = N,N-bis(4-pyridinecarboxamide)-1,4-butane, SIP = 5-sulfoisophthalate) is hydrothermally synthesized. X-ray diffraction analysis reveals that compound 1 is composed of 2D anionic $[Cu_2(SIP)_2(L)_2]_n{^{2n-}}$ double-layers and discrete 1D cationic $[CuL(H_2O)_4]_n{^{2n+}}$ polymeric chains, which represents a rare 3D polypseudo-rotaxane MOF from intercalation of 1D and 2D framework. In addition, the luminescent property and electrochemical behavior of compound 1 have been investigated.

Electrochemical Characteristics of $MnO_2$ coated electrodes as a function of manufacturing method (제조방법에 따른 $MnO_2$ coating 전극의 전기화학적 특성)

  • Kim, Hyun-Sik;Lee, Hae-Yon;Huh, Jeong-Seob;An, Yong-Woon;Kim, Jong-Ryung;Park, Hye-Young
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.1740-1742
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    • 2004
  • 산소 과전압이 낮은 $MnO_2$를 촉매로 사용하여 반도체 산화물계의 산소선택성 전극을 제조하고 산화물 코팅층의 미세구조와 전기화학적 특성을 분석하였다. Ti 기판에 열분해 법을 이용하여 $MnO_2$ 피막을 형성하였고, 또한 binder를 이용한 코팅 방법을 이용하여 Ti, Fb 기판에 $MnO_2$ 피막층을 형성하였다. 450$^{\circ}C$에서 1시간 열분해하여 약 1 ${\mu}m$$MnO_2$ 피막층을 형성 시켰으나 Ti 기판과의 접착력이 약하여 피막자체에 대한 전기화학적 특성은 관찰할 수 없었다. PVDF : $MnO_2$의 함량비가 1:1에서 1:6 까지는 DMF의 함량에 무관하게 전극 특성이 나타나지 않았지만 20:1 이상의 조성에서는 균일한 C-V 특성을 나타냈고, 산소 발생 과전압도 약 1.4V 정도로 감소되었다. 그러나 Ti 기판의 경우 열분해법을 이용하여 제조된 전극과 같이 낮은 기판과의 접착력 때문에 $MnO_2$ 피막층의 촉매효과가 현저하게 감소하였다.

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A Study for the Norms of Audiometric Tests in Koreans (정상한국인의 청력검사치에 관한 연구)

  • 오혜경;서장수;이근해;김희남;김영명;권영화;서옥기
    • Proceedings of the KOR-BRONCHOESO Conference
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    • 1981.05a
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    • pp.38.1-38
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    • 1981
  • Currently in the otologic field, there are various methods of special audiometric examinations, such as, tone decay, SISI, and impedance audiometry and only a few studies has been done in these fields sporadically in Korea. The purpose of this paper is to establish norms of various special audiometric tests, so we have performed the special audiometric tests on 100 male medical students in good physical condition and the follow results were obtained. 1. All cases showed over 90% of PB scores. The mean and its 2 S.D. were 98$\pm$4.9% in the right ear and 97$\pm$5.6% in the left ear. 2. The mean and its 2 S.D. of MCL(most comfortable level) were 45$\pm$15.4 dB in the right ear and 46$\pm$17.9 dB in the left ear, and its range was 12$\pm$12.2 dB in the right ear and 13$\pm$12.6 dB in the left ear. 3. The mean and its 2 S.D. of UCL (uncomfortable level) were 102$\pm$7.9 dB in the right ear and 102$\pm$7.9 dB in the left ear and about an half in cases showed over 106 dB of UCL. 4. In 95% of cases, SISIs(short increment sensitivity index) at 1, 000 Hz and 4000 Hz was below 45% in the right ear in both frequencies and below 55% and 75% in the left ear, respectively. 5. In 95% of cases, tone decays at 2, 000 Hz and 4, 000 Hz was below 10 dB in both ears. 6. The difference between SRT and PTA (speech reception threshold minus pure tone average) was 4$\pm$9.2 dB in the right ear and 4$\pm$10.0 dB in the left ear. 7. The dynamic range(uncomfortable level minus speech reception threshold) was 98$\pm$13.5 dB in the right ear and 99$\pm$13.5 dB in the left ear. We had trouble in estimating the dynamic range in about an half in cases, in which we couldn't estimate the UCL with our conventional audiometry. 8. The results of impedance audiometric tests were as follow: A. In the tympanogram, all cases were of A type with one exception of B type in the left ear. The mean and its 2 S.D. of its peak level were 22.8$\pm$32.94mm $H_2O$ in the right ear and 23.9$\pm$29. 81mm $H_2O$ in the left ear. B. The mean and its 2 S.D. of the compliance were 0.6$\pm$0.54cc in the right ear and 0.6$\pm$0.53cc in the left ear. C. The results of stapedial reflex: a. The mean and its 2 S.D. of the controlateral stapedial reflex at 500Hz, 1, 000Hz, 2, 000Hz, 4, 000Hz were 99$\pm$17.7 dB, 87$\pm$14.4 dB, 79$\pm$13.7 dB, 77$\pm$20.0 dB in the right ear and 99$\pm$15.9 dB, 88$\pm$13.9 dB, 79$\pm$13.7 dB, 77$\pm$21.3 dB in the left ear. Depending on the tested frequencies, the stapedial reflex wasn't generated in 6 cases in the right ear and 11 cases in the left ear. b. The mean and its 2 S.D. of the ipsilateral stapedial reflex at 1, 000Hz, and 2, 000Hz were 89$\pm$16.3 dB, 82$\pm$15.9 dB in the right ear and 89$\pm$18.0 dB, 83$\pm$18.9 dB in the left ear. Depending on the tested frequencies, the stapedial reflex wans't generated in 1 case in the right ear and 2 cases in the left ear. 9. Eustachian tube function using with impedance audiometry was malfunctioned in21 cases depending on the tested pressure and the range of peak level of tympanogram was 14$\pm$26.9mm $H_2O$(tested pressure:+250mm $H_2O$), 8$\pm$21.9mm $H_2O$ (tested pressure:-250mm $H_2O$) in the right ear and 11 cases depending on the tested pressure and the range of the peak level of tympanogram was 12$\pm$22.5mm $H_2O$ (tested pressure: +250 mm $H_2O$, 9$\pm$17.3mm $H_2O$(tested pressure: -250mm $H_2O$) in the left ear.

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Constituents of Sanguisorba hakusanensis Leaves (산오이풀 잎의 성분)

  • Kwon, Won-Jun;Whang, Wan-Kyunn;Kim, Il-Hyuk
    • YAKHAK HOEJI
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    • v.40 no.3
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    • pp.262-272
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    • 1996
  • The constituents of Sanguisorba hakusanensis leaves (Rosaceae), of which the roots have been used as an astringent, hemostatics and antiphlogistics, were studied phytoche mically. From water fraction of the MeOH extract, gallic acid 3-O-${\beta}$-D-(6'-O-galloyl)-glucopyranoside(I), quercetin-3-O-${\beta$-D-galactopyranoside(II), quercetin-3-O-${\alpha}$-L-arabinopyranoside(III) and $2{\alpha},\;3{\beta},\;19{\alpha}$, 23-tetrahydroxyurs-12-en-28-oic acid 28-O-${\beta}$-D-glucopyranoside(IV) were isolated by column chromatographic separation using Amberlite XAD-2, ODS-gel and Sephadex LH-20. The structure of these compounds were elucidated by spectroscopic parameters of $^1H$-NMR, $^{13}C$-NMR, $^1H-^1H$ COSY, $^{13}C-^1H$ COSY, EI-Mass, FAB-Mass, IR, UV and by comparison with authentic samples.

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Two-Dimensional Nickel Coordination Polymers: Ni(OBC)(bipyen)]·H2O and [Ni(NDC)(bipyen)(H2O)] (NDC = 2,6-Naphthalenedicarboxylate; OBC = 4,4'-Oxybis(benzoate); bipyen = trans-1,2-Bis(4-pyridyl)ethylene)

  • Lee, Yeon-Kyoung;Lee, Soon W.
    • Bulletin of the Korean Chemical Society
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    • v.24 no.7
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    • pp.906-910
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    • 2003
  • Hydrothermal reactions of Ni(NO₃)₂· 6H₂O with trans-1,2-bis(4-pyridyl)ethylene (bipyen), in the presence of a linear 2,6-naphthalene dicarboxylic acid (NDCH₂) and a bent 4,4'-oxybis(benzoic acid) (OBCH₂), gave a 2-D coordination polymer [Ni(NDC)(bipyen)(H₂O)] (1) and also a 2-D coordination polymer [Ni(OBC)(bipyen)]· H₂O (2), respectively. A reversible de-coordination and re-coordination of an aqua ligand was observed for polymer 1. Polymer 2 has an undulated 2-D network based on 50-membered rectangular grids, each of which has the dimension of 13.61 × 13.17 Å.

Application of Layered Perovskites Substituted with Co and Ti as Electrodes in SOFCs (Co 및 Ti가 치환된 Layered perovskite의 SOFC 전극에 대한 적용성 연구)

  • Kim, Chan Gyu;Shin, Tae Ho;Nam, Jung Hyun;Kim, Jung Hyun
    • New & Renewable Energy
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    • v.18 no.2
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    • pp.40-49
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    • 2022
  • In this study, the phase and electrochemical properties of Co and Ti substituted layered perovskites SmBaCo2-xTixO5+d (x=0.5, 0.7, 1.0, 1.1, 1.3, and 1.5) were analyzed, and their application as electrodes in solid oxide fuel cells (SOFCs) were evaluated. After calcination at 1300℃ for 6 h, a single phase was observed for two compositions of the SmBaCo2-xTixO5+d oxide system, SmBaCoTiO5+d (x=1.0) and SmBaCo0.9Ti1.1O5+d (x=1.1). However, the phases of SmBaCoTiO5+d (SBCTO) and SmTiO3 coexisted for compositions with x≥1.3 (Ti content). In contrast, for compositions of x≤0.7, the SmBaCo2O5+d phase was observed instead of the SmTiO3 phase. To evaluate the applicability of these materials as SOFC electrodes, the electrical conductivities were measured under various atmospheres (air, N2, and H2). SBCTO exhibited stable semi-conductor electrical conductivity behavior in an air and N2 atmosphere. However, SBCTO showed insulator behavior at temperatures above 600℃ in a H2 atmosphere. Therefore, SBCTO may only be used as cathode materials. Moreover, SBCTO had an area specific resistance (ASR) value of 0.140 Ω·cm2 at 750℃.

Phenolic Compounds from Seeds of Astragalus sinicus and Its Antioxidative Activities (자운영(Astragalus sinicus)종자의 페놀성 화합물 및 항산화 활성)

  • Yeom, Seung-Hwan;Kim, Min-Kee;Kim, Hyun-Jung;Shim, Jae-Geul;Lee, Jae-Hee;Lee, Min-Won
    • Korean Journal of Pharmacognosy
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    • v.34 no.4 s.135
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    • pp.344-351
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    • 2003
  • Phytochemical examination of seeds of Astragalus sinicus has led to the isolation and characterization of kaempferol $3-O-{\beta}-D-apiofuranosyl-(1{\rightarrow}2)-{\alpha}-L-rhamnopyranosyl-(1{\rightarrow}6)-{\beta}-D-glucopyranoside$ (1), quercetin $3-O-{\beta}-D-xylopyranosyl-(1{\rightarrow}2)-{\beta}-D-glucopyranoside$ (2), ampelopsin (3), ampelopsin $3'-O-{\beta}-D-xylopyranoside$ (4), ampelopsin $3'-O-{\beta}-Dxylopyranoside$ (5), myricetin (6), myricetin $3'-O-{\beta}-D-glucopyranoside$ (7), myricetin $3'-O-{\beta}-D-xylopyranoside$ (8). Antioxidative activity of these compounds was determined by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. Flavanonols(3,4, and 5) showed potent antioxidative activity.